Sample records for type tunnel lengthm

  1. Passivated Tunneling Contacts to N-Type Wafer Silicon and Their Implementation into High Performance Solar Cells: Preprint

    SciTech Connect (OSTI)

    Stradins, P.; Essig, S.; Nemeth, W.; Lee, B. G.; Young, D.; Norman, A.; Liu, Y.; Luo, J.-W.; Warren, E.; Dameron, A.; LaSalvia, V.; Page, M.; Rohatgi, A.; Upadhyaya, A.; Rounsaville, B.; Ok, Y.-W.; Glunz, S.; Benick, J.; Feldmann, F.; Hermle, M.

    2014-12-01T23:59:59.000Z

    We present a case that passivated contacts based on a thin tunneling oxide layer, combined with a transport layer with properly selected work function and band offsets, can lead to high efficiency c-Si solar cells. Passivated contacts contribute to cell efficiency as well as design flexibility, process robustness, and a simplified process flow. Material choices for the transport layer are examined, including transparent n-type oxides and n+-doped poly-Si. SiO2/n+-poly-Si full-area, induced-junction back surface field contacts to n-FZ and n-Cz Si are incorporated into high efficiency cells with deep, passivated boron emitters.

  2. Tunneling study on HTS -digest version-

    E-Print Network [OSTI]

    Tonouchi, Masayoshi

    Tunneling study on HTS -digest version- Tunneling study on HTS -digest version- #12;Type contact tunneling #12;Tunneling spectra observed with different types of probes. (a):600Ê mÓ Pt wire, (b):200Ê mÓ Ag wire of coil shaped and (c):30Ê mÓ Au wire probes. The corresponding surface SEM image were

  3. Type B Accident Investigation Board Report on the August 5, 1998, Load Haul Dump Accident at U16b Tunnel, Nevada Test Site

    Broader source: Energy.gov [DOE]

    Thisis theType B Accident Investigation Board report of an industrial accident at the Nevada Test site (NTS), U16b tunnel in which a Bechtel Nevada (BN) employee suffered a compressed skull fracture as a result of being struck onthe head by a valve and fitting assembly on the end of a hose whichhad been broken from a water pipe by a moving piece of construction equipment.

  4. Channel tunnel

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    Jacques Lemley, américain et "chief executif" parle du projet de l'Eurotunnel - tunnel sous la manche

  5. Effect of unitary impurities on non-STM types of tunneling in high-T-c superconductors

    E-Print Network [OSTI]

    Zhu, JX; Ting, CS; Hu, Chia-Ren.

    2000-01-01T23:59:59.000Z

    ?4 or twin5 boundary. These MS?s form an ??essentially dispersionless?? branch of elementary excitations, in the PRB 620163-1829/2000/62~9!/6027~10!/$15.00 s of tunneling in high-Tc superconductors d C. S. Ting , University of Houston, Houston, Texas... that HTSC?s are DWSC?s, and isolated unitary impurities do pos- sess near-zero energy resonant states which can be observed as a ZBCP-like feature by STM/S in the close vicinity of PRB 62, AND CHIA-REN HU such an impurity, can any concentration of a...

  6. Property:Maximum Wave Length(m) | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere I Geothermal PwerPerkins County, Nebraska:PrecourtOid JumpEligSysSize JumpTechDsc Jump to:" Showing 18

  7. Dynamical tunneling and control

    E-Print Network [OSTI]

    Srihari Keshavamurthy

    2011-07-25T23:59:59.000Z

    This article summarizes the recent work on the influence of dynamical tunneling on the control of quantum systems. Specifically, two examples are discussed. In the first, it is shown that the bichromatic control of tunneling in a driven double well system is hampered by the phenomenon of chaos-assisted tunneling. The bichromatic control landscape exhibits several regions indicating lack of control with every such region involving chaos-assisted tunneling. The second example illustrates the failure of controlling the dissociation dynamics of a driven Morse oscillator due to the phenomenon of resonance-assisted tunneling. In particular, attempts to control the dissociation dynamics by rebuilding local phase space barriers are foiled due to resonance-assisted tunneling.

  8. Ti-substituted tunnel-type Na0.44MnO2 oxide as a negative electrode for aqueous sodium-ion batteries

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wang, Yuesheng [Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics (IHEP); Liu, Jue [Brookhaven National Lab. (BNL), Upton, NY (United States); Lee, Byungju [Seoul National Univ. (Korea, Republic of); Qiao, Ruimin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source; Yang, Zhenzhong [Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics (IHEP); Xu, Shuyin [Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics (IHEP); Yu, Xiqian [Brookhaven National Lab. (BNL), Upton, NY (United States)] (ORCID:000000018513518X); Gu, Lin [Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics (IHEP); Hu, Yong-Sheng [Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics (IHEP)] (ORCID:0000000284306474); Yang, Wanli [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source] (ORCID:0000000306668063); Kang, Kisuk [Seoul National Univ. (Korea, Republic of); Li, Hong [Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics (IHEP)] (ORCID:000000028659086X); Yang, Xiao-Qing [Brookhaven National Lab. (BNL), Upton, NY (United States); Chen, Liquan [Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics (IHEP); Huang, Xuejie [Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics (IHEP)

    2015-03-25T23:59:59.000Z

    The aqueous sodium-ion battery system is a safe and low-cost solution for large-scale energy storage, due to the abundance of sodium and inexpensive aqueous electrolytes. Although several positive electrode materials, e.g., Na0.44MnO2, were proposed, few negative electrode materials, e.g., activated carbon and NaTi2(PO4)3, are available. Here we show that Ti-substituted Na0.44MnO2 (Na0.44[Mn1-xTix]O2) with tunnel structure can be used as a negative electrode material for aqueous sodium-ion batteries. This material exhibits superior cyclability even without the special treatment of oxygen removal from the aqueous solution. Atomic-scale characterizations based on spherical aberration-corrected electron microscopy and ab initio calculations are utilized to accurately identify the Ti substitution sites and sodium storage mechanism. Ti substitution tunes the charge ordering property and reaction pathway, significantly smoothing the discharge/charge profiles and lowering the storage voltage. Both the fundamental understanding and practical demonstrations suggest that Na0.44[Mn1-xTix]O2 is a promising negative electrode material for aqueous sodium-ion batteries.

  9. Ti-substituted tunnel-type Na0.44MnO2 oxide as a negative electrode for aqueous sodium-ion batteries

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wang, Yuesheng; Liu, Jue; Lee, Byungju; Qiao, Ruimin; Yang, Zhenzhong; Xu, Shuyin; Yu, Xiqian; Gu, Lin; Hu, Yong-Sheng; Yang, Wanli; et al

    2015-03-25T23:59:59.000Z

    The aqueous sodium-ion battery system is a safe and low-cost solution for large-scale energy storage, due to the abundance of sodium and inexpensive aqueous electrolytes. Although several positive electrode materials, e.g., Na0.44MnO2, were proposed, few negative electrode materials, e.g., activated carbon and NaTi2(PO4)3, are available. Here we show that Ti-substituted Na0.44MnO2 (Na0.44[Mn1-xTix]O2) with tunnel structure can be used as a negative electrode material for aqueous sodium-ion batteries. This material exhibits superior cyclability even without the special treatment of oxygen removal from the aqueous solution. Atomic-scale characterizations based on spherical aberration-corrected electron microscopy and ab initio calculations are utilized to accuratelymore »identify the Ti substitution sites and sodium storage mechanism. Ti substitution tunes the charge ordering property and reaction pathway, significantly smoothing the discharge/charge profiles and lowering the storage voltage. Both the fundamental understanding and practical demonstrations suggest that Na0.44[Mn1-xTix]O2 is a promising negative electrode material for aqueous sodium-ion batteries.« less

  10. Tunneling of Polymer Particles

    E-Print Network [OSTI]

    A. Martín-Ruiz; E. Chan-López; A. Carbajal-Domínguez; J. Bernal

    2014-08-28T23:59:59.000Z

    In this paper we study the tunneling using a background independent (polymer) quantization scheme. We show that at low energies, for the tunneling through a single potential barrier, the polymer transmission coefficient and the polymer tunneling time converge to its quantum-mechanical counterparts in a clear fashion. As the energy approaches the maximum these polymer quantities abruptly decrease to zero. We use the transfer matrix method to study the tunneling through a series of identical potential barriers. We obtain that the transmission coefficients (polymer and quantum-mechanical) behave qualitatively in a similar manner, as expected. Finally we show that the polymer tunneling time exhibits anomalous peaks compared with the standard result. Numerical results are also presented.

  11. Ultrafast scanning tunneling microscopy

    SciTech Connect (OSTI)

    Botkin, D.A. [California Univ., Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley Lab., CA (United States)

    1995-09-01T23:59:59.000Z

    I have developed an ultrafast scanning tunneling microscope (USTM) based on uniting stroboscopic methods of ultrafast optics and scanned probe microscopy to obtain nanometer spatial resolution and sub-picosecond temporal resolution. USTM increases the achievable time resolution of a STM by more than 6 orders of magnitude; this should enable exploration of mesoscopic and nanometer size systems on time scales corresponding to the period or decay of fundamental excitations. USTM consists of a photoconductive switch with subpicosecond response time in series with the tip of a STM. An optical pulse from a modelocked laser activates the switch to create a gate for the tunneling current, while a second laser pulse on the sample initiates a dynamic process which affects the tunneling current. By sending a large sequence of identical pulse pairs and measuring the average tunnel current as a function of the relative time delay between the pulses in each pair, one can map the time evolution of the surface process. USTM was used to measure the broadband response of the STM`s atomic size tunnel barrier in frequencies from tens to hundreds of GHz. The USTM signal amplitude decays linearly with the tunnel junction conductance, so the spatial resolution of the time-resolved signal is comparable to that of a conventional STM. Geometrical capacitance of the junction does not appear to play an important role in the measurement, but a capacitive effect intimately related to tunneling contributes to the measured signals and may limit the ultimate resolution of the USTM.

  12. Risk analysis for tunneling projects

    E-Print Network [OSTI]

    Sousa. Rita L

    2010-01-01T23:59:59.000Z

    Tunnel construction is increasing world wide. Although the majority of tunnel construction projects have been completed safely, there have been several incidents that have resulted in delays, cost overruns, and sometimes ...

  13. Multiple percolation tunneling staircase in metal-semiconductor nanoparticle composites

    SciTech Connect (OSTI)

    Mukherjee, Rupam; Huang, Zhi-Feng; Nadgorny, Boris [Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201 (United States)

    2014-10-27T23:59:59.000Z

    Multiple percolation transitions are observed in a binary system of RuO{sub 2}-CaCu{sub 3}Ti{sub 4}O{sub 12} metal-semiconductor nanoparticle composites near percolation thresholds. Apart from a classical percolation transition, associated with the appearance of a continuous conductance path through RuO{sub 2} metal oxide nanoparticles, at least two additional tunneling percolation transitions are detected in this composite system. Such behavior is consistent with the recently emerged picture of a quantum conductivity staircase, which predicts several percolation tunneling thresholds in a system with a hierarchy of local tunneling conductance, due to various degrees of proximity of adjacent conducting particles distributed in an insulating matrix. Here, we investigate a different type of percolation tunneling staircase, associated with a more complex conductive and insulating particle microstructure of two types of non-spherical constituents. As tunneling is strongly temperature dependent, we use variable temperature measurements to emphasize the hierarchical nature of consecutive tunneling transitions. The critical exponents corresponding to specific tunneling percolation thresholds are found to be nonuniversal and temperature dependent.

  14. Scanning tunneling microscope nanoetching method

    DOE Patents [OSTI]

    Li, Yun-Zhong (West Lafayette, IN); Reifenberger, Ronald G. (West Lafayette, IN); Andres, Ronald P. (West Lafayette, IN)

    1990-01-01T23:59:59.000Z

    A method is described for forming uniform nanometer sized depressions on the surface of a conducting substrate. A tunneling tip is used to apply tunneling current density sufficient to vaporize a localized area of the substrate surface. The resulting depressions or craters in the substrate surface can be formed in information encoding patterns readable with a scanning tunneling microscope.

  15. Ferroelectric tunneling element and memory applications which utilize the tunneling element

    DOE Patents [OSTI]

    Kalinin, Sergei V. (Knoxville, TN) [Knoxville, TN; Christen, Hans M. (Knoxville, TN) [Knoxville, TN; Baddorf, Arthur P. (Knoxville, TN) [Knoxville, TN; Meunier, Vincent (Knoxville, TN) [Knoxville, TN; Lee, Ho Nyung (Oak Ridge, TN) [Oak Ridge, TN

    2010-07-20T23:59:59.000Z

    A tunneling element includes a thin film layer of ferroelectric material and a pair of dissimilar electrically-conductive layers disposed on opposite sides of the ferroelectric layer. Because of the dissimilarity in composition or construction between the electrically-conductive layers, the electron transport behavior of the electrically-conductive layers is polarization dependent when the tunneling element is below the Curie temperature of the layer of ferroelectric material. The element can be used as a basis of compact 1R type non-volatile random access memory (RAM). The advantages include extremely simple architecture, ultimate scalability and fast access times generic for all ferroelectric memories.

  16. ANDREW W. TUNNELL

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy China 2015ofDepartmentDepartment of2 of 5) ALARA TrainingANDREW W. TUNNELL t: (205)

  17. Gravitational Tunneling Radiation

    E-Print Network [OSTI]

    Mario Rabinowitz

    2002-12-11T23:59:59.000Z

    The isolated black hole radiation of both Hawking and Zel'dovich are idealized abstractions as there is always another body to distort the potential. This is considered with respect to both gravitational tunneling, and black hole "no-hair" theorems. The effects of a second body are to lower the gravitational barrier of a black hole and to give the barrier a finite rather than infinite width so tha a particle can escape by tunneling (as in field emission) or over the top of the lowered barrier (as in Schottky emission). Thus radiation may be emitted from black holes in a process differing from that of Hawking radiation, P SH, which has been undetected for over 24 years. The radiated power from a black hole derived here is PR e ^2__ PSH, where e ^2__ is he ransmission probability for radiation through the barrier. This is similar to electric field emission of electrons from a metal in that the emission can in principle be modulated and beamed. The temperature and entropy of black holes are reexamined. Miniscule black holes herein may help explain the missing mass of the universe, accelerated expansion of the universe, and anomalous rotation of spiral galaxies. A gravitational interference effect for black hole radiation similar to the Aharonov-Bohm effect is also examined.

  18. Two tunnels to inflation

    SciTech Connect (OSTI)

    Aguirre, Anthony; Johnson, Matthew C. [Department of Physics, University of California, Santa Cruz, California 95064 (United States)

    2006-06-15T23:59:59.000Z

    We investigate the formation via tunneling of inflating (false-vacuum) bubbles in a true-vacuum background, and the reverse process. Using effective potentials from the junction condition formalism, all true- and false-vacuum bubble solutions with positive interior and exterior cosmological constant, and arbitrary mass are catalogued. We find that tunneling through the same effective potential appears to describe two distinct processes: one in which the initial and final states are separated by a wormhole (the Farhi-Guth-Guven mechanism), and one in which they are either in the same hubble volume or separated by a cosmological horizon. In the zero-mass limit, the first process corresponds to the creation of an inhomogenous universe from nothing, while the second mechanism is equivalent to the nucleation of true- or false-vacuum Coleman-De Luccia bubbles. We compute the probabilities of both mechanisms in the WKB approximation using semiclassical Hamiltonian methods, and find that--assuming both process are allowed--neither mechanism dominates in all regimes.

  19. Flatback airfoil wind tunnel experiment.

    SciTech Connect (OSTI)

    Mayda, Edward A. (University of California, Davis, CA); van Dam, C.P. (University of California, Davis, CA); Chao, David D. (University of California, Davis, CA); Berg, Dale E.

    2008-04-01T23:59:59.000Z

    A computational fluid dynamics study of thick wind turbine section shapes in the test section of the UC Davis wind tunnel at a chord Reynolds number of one million is presented. The goals of this study are to validate standard wind tunnel wall corrections for high solid blockage conditions and to reaffirm the favorable effect of a blunt trailing edge or flatback on the performance characteristics of a representative thick airfoil shape prior to building the wind tunnel models and conducting the experiment. The numerical simulations prove the standard wind tunnel corrections to be largely valid for the proposed test of 40% maximum thickness to chord ratio airfoils at a solid blockage ratio of 10%. Comparison of the computed lift characteristics of a sharp trailing edge baseline airfoil and derived flatback airfoils reaffirms the earlier observed trend of reduced sensitivity to surface contamination with increasing trailing edge thickness.

  20. Relativistic tunneling through opaque barriers

    SciTech Connect (OSTI)

    De Leo, Stefano; Leonardi, Vinicius [Department of Applied Mathematics, State University of Campinas, SP 13083-970, Campinas (Brazil)

    2011-02-15T23:59:59.000Z

    We propose an analytical study of relativistic tunneling through opaque barriers. We obtain a closed formula for the phase time. This formula is in excellent agreement with the numerical simulations and corrects the standard formula obtained by the stationary phase method. An important result is found when the upper limit of the incoming energy distribution coincides with the upper limit of the tunneling zone. In this case, the phase time is proportional to the barrier width.

  1. Scanning Tunneling Microscopy currents on locally disordered graphene

    E-Print Network [OSTI]

    Tsai, Shan-Wen; Peres, Nuno M. R.; Santos, J. E.; Ribeiro, R. M.

    2009-01-01T23:59:59.000Z

    Scanning Tunneling Microscopy currents on locally disorderedcharacteristic curves of Scanning Tunneling Microscopy (STM)for the calculation of Scanning Tunneling Microscopy (STM)

  2. Scanning Tunneling Spectroscopy of Graphene and Magnetic Nanostructures

    E-Print Network [OSTI]

    Brar, Victor Watson

    2010-01-01T23:59:59.000Z

    C. J. Chen, Introduction to Scanning Tunneling Microscopy (Scanning Tunneling Spectroscopy of Graphene and MagneticAli Javey Fall 2010 Scanning Tunneling Spectroscopy of

  3. Development of a wireless sensor unit for tunnel monitoring

    E-Print Network [OSTI]

    Cheekiralla, Sivaram M. S. L., 1980-

    2004-01-01T23:59:59.000Z

    In this thesis we describe the development of a wireless sensor module for tunnel monitoring. The tunnel in question is a part of the London Underground system. Construction of a new tunnel beneath the existing tunnel is ...

  4. Tunnel ventilation effectiveness in fire scenarios 

    E-Print Network [OSTI]

    Colella, Francesco; Rein, Guillermo; Carvel, Ricky O; Torero, Jose L

    2010-01-01T23:59:59.000Z

    Throughout most of a tunnel network the ventilation behaviour may be approximated with a simple 1D flow model. However, there are some important - but relatively small - regions of the tunnel that require CFD analysis. The multi-scale model...

  5. Monolithic interconnected module with a tunnel junction for enhanced electrical and optical performance

    DOE Patents [OSTI]

    Murray, Christopher S. (Bethel Park, PA); Wilt, David M. (Bay Village, OH)

    2000-01-01T23:59:59.000Z

    An improved thermophotovoltaic (TPV) n/p/n device is provided. Monolithic Interconnected Modules (MIMS), semiconductor devices converting infrared radiation to electricity, have been developed with improved electrical and optical performance. The structure is an n-type emitter on a p-type base with an n-type lateral conduction layer. The incorporation of a tunnel junction and the reduction in the amount of p-type material used results in negligible parasitic absorption, decreased series resistance, increased voltage and increased active area. The novel use of a tunnel junction results in the potential for a TPV device with efficiency greater than 24%.

  6. Two types of the relation between the intensity and the life time of photoluminescence of core/shell semiconductor quantum dots: Important role of Coulomb field and tunneling transitions

    SciTech Connect (OSTI)

    Osad'ko, I. S., E-mail: osadko@isan.troitsk.ru [Institute for spectroscopy RAS, Troitsk, 142190 Moscow (Russian Federation)

    2014-10-28T23:59:59.000Z

    It has been recently found [Gh. Galland, Y. Ghosh, A. Steinbrück, M. Sykora, J. A. Hollingsworth, and V. I. Klimov, Nature (London) 479, 203 (2011)] that semiconductor core/shell nanocrystals (NCs) with blinking photoluminescence (PL) can be of “A” or “B” type. NCs of A-type exhibit correlation between the intensity of PL and the life time. In NCs of B-type such correlation is absent. Simple model based on combination of the charging model and the two-level system model is proposed for describing emissive properties of NCs of both types. The model invokes fluctuations of emission ability ?{sub em} of NC to explain the emissive properties of NCs of B-type. Our combined model is also in agreement with anticorrelation between the duration ?{sub off} of off intervals and PL life time t{sub off} in off intervals found recently for NCs of A-type in the experiment [A. A. Cordones, T. J. Bixby, and S. R. Leone, Nano Lett. 11, 3366 (2011)].

  7. High Tunnels: A First Years Experience Ron Goldy, MSUE and

    E-Print Network [OSTI]

    ). This is a report on our experience. Tunnel Construction The tunnel consists of pipe, hardware, wire, plastic in tunnel plants went a foot or more over the stake and had more lateral growth. `Mt. Spring' total fruit

  8. Superconducting Tunnel Junctions as Direct Detectors for Submillimeter Astronomy

    E-Print Network [OSTI]

    Superconducting Tunnel Junctions as Direct Detectors for Submillimeter Astronomy A Dissertation 2008 by John Daniel Teufel. All rights reserved. #12;Abstract Superconducting Tunnel Junctions on the of performance of superconducting tunnel junctions (STJ) as direct detectors for submillimeter radiation. Over

  9. MASON LAB B-7 WIND TUNNEL OPERATING INSTRUCTIONS Our wind tunnel is a low speed tunnel with a test section 15"x24" It has a digital controller

    E-Print Network [OSTI]

    Haller, Gary L.

    MASON LAB B-7 WIND TUNNEL OPERATING INSTRUCTIONS Our wind tunnel is a low speed tunnel with a test up to a maximum velocity of about 39M/s (~130 feet/s , 88mph) We have a 2 axis force balance that can measure lift (~25 N) and drag (~8 N) PRECAUTIONS: ALL OBJECTS MUST BE SECURED BEFORE STARTING WIND TUNNEL

  10. A Historical Evaluation of the U16a Tunnel, Nevada National Security Site, Nye County, Nevada Volume 2

    SciTech Connect (OSTI)

    Jones, Roberrt C [DRI; Drollinger, Harold [DRI

    2013-06-01T23:59:59.000Z

    This report presents a historical evaluation of the U16a Tunnel on the Nevada National Security Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency. The U16a Tunnel was used for underground nuclear weapons effects tests in Shoshone Mountain in Area 16 of the Nevada National Security Site. Six nuclear tests were conducted in the U16a Tunnel from 1962 to 1971. These tests are Marshmallow, Gum Drop, Double Play, Ming Vase, Diamond Dust, and Diamond Mine. The U.S. Department of Defense Threat Reduction Agency, with participation from Lawrence Livermore National Laboratory and Las Alamos National Laboratory, sponsored the tests. Fifteen high explosives tests were also conducted at the tunnel. Two were calibration tests during nuclear testing and the remaining were U.S. Department of Defense, Defense Threat Reduction Agency tunnel defeat tests. The U16a Tunnel complex is on the top and slopes of Shoshone Mountain, encompassing an area of approximately 16.7 hectares (41.1 acres). Major modifications to the landscape are a result of three principal activities, road construction and maintenance, mining activities related to development of the tunnel complex, and site preparation for activities related to testing. Forty-seven cultural features were recorded at the portal and on the slopes of Shoshone Mountain. At the portal area, features relate to the mining, construction, testing, and general every day operational support activities within the tunnel. These include concrete foundations for buildings, equipment pads, and rail lines. Features on the slopes above the tunnel relate to tunnel ventilation, borehole drilling, and data recording. Feature types include soil-covered bunkers, concrete foundations, instrument cable holes, drill holes, and ventilation shafts. The U16a Tunnel complex is eligible to the National Register of Historic Places under criteria a and c, consideration g of 36 CFR Part 60.4 as a historic landscape. Scientific research conducted at the tunnel has made significant contributions to the broad patterns of our history, particularly in regard to the Cold War era that was characterized by competing social, economic, and political ideologies between the former Soviet Union and the United States. The tunnel also possesses distinctive construction and engineering methods for conducting underground nuclear tests. The Desert Research Institute recommends that the U16a Tunnel area be left in place in its current condition and that the U16a Tunnel historic landscape be included in the Nevada National Security Site monitoring program and monitored on a regular basis.

  11. A Historical Evaluation of the U16a Tunnel, Nevada National Security Site, Nye County, Nevada Volume 1

    SciTech Connect (OSTI)

    Jones, robert C [DRI; Drollinger, Harold [DRI; Bullard, Thomas F [DRI; Ashbaugh, Laurence J [DRI; Griffin, Wayne R [DRI

    2013-06-01T23:59:59.000Z

    This report presents a historical evaluation of the U16a Tunnel on the Nevada National Security Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency. The U16a Tunnel was used for underground nuclear weapons effects tests in Shoshone Mountain in Area 16 of the Nevada National Security Site. Six nuclear tests were conducted in the U16a Tunnel from 1962 to 1971. These tests are Marshmallow, Gum Drop, Double Play, Ming Vase, Diamond Dust, and Diamond Mine. The U.S. Department of Defense Threat Reduction Agency, with participation from Lawrence Livermore National Laboratory and Las Alamos National Laboratory, sponsored the tests. Fifteen high explosives tests were also conducted at the tunnel. Two were calibration tests during nuclear testing and the remaining were U.S. Department of Defense, Defense Threat Reduction Agency tunnel defeat tests. The U16a Tunnel complex is on the top and slopes of Shoshone Mountain, encompassing an area of approximately 16.7 hectares (41.1 acres). Major modifications to the landscape are a result of three principal activities, road construction and maintenance, mining activities related to development of the tunnel complex, and site preparation for activities related to testing. Forty-seven cultural features were recorded at the portal and on the slopes of Shoshone Mountain. At the portal area, features relate to the mining, construction, testing, and general every day operational support activities within the tunnel. These include concrete foundations for buildings, equipment pads, and rail lines. Features on the slopes above the tunnel relate to tunnel ventilation, borehole drilling, and data recording. Feature types include soil-covered bunkers, concrete foundations, instrument cable holes, drill holes, and ventilation shafts. The U16a Tunnel complex is eligible to the National Register of Historic Places under criteria a and c, consideration g of 36 CFR Part 60.4 as a historic landscape. Scientific research conducted at the tunnel has made significant contributions to the broad patterns of our history, particularly in regard to the Cold War era that was characterized by competing social, economic, and political ideologies between the former Soviet Union and the United States. The tunnel also possesses distinctive construction and engineering methods for conducting underground nuclear tests. The Desert Research Institute recommends that the U16a Tunnel area be left in place in its current condition and that the U16a Tunnel historic landscape be included in the Nevada National Security Site monitoring program and monitored on a regular basis.

  12. Enhancement of tunnel magnetoresistance in magnetic tunnel junction by a superlattice barrier

    SciTech Connect (OSTI)

    Chen, C. H.; Hsueh, W. J., E-mail: hsuehwj@ntu.edu.tw [Nanomagnetism Group, Department of Engineering Science and Ocean Engineering, National Taiwan University, 1, Sec. 4, Roosevelt Road, Taipei 10660, Taiwan (China)

    2014-01-27T23:59:59.000Z

    Tunnel magnetoresistance of magnetic tunnel junction improved by a superlattice barrier composed of alternate layers of a nonmagnetic metal and an insulator is proposed. The forbidden band of the superlattice is used to predict the low transmission range in the superlattice barrier. By forbidding electron transport in the anti-parallel configuration, the tunnel magnetoresistance is enhanced in the superlattice junction. The results show that the tunnel magnetoresistance ratio for a superlattice magnetic tunnel junction is greater than that for traditional single or double barrier junctions.

  13. Design and Commissioning of a Wind Tunnel for Integrated Physical...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Commissioning of a Wind Tunnel for Integrated Physical and Chemical Measurements of PM Dispersing Plume of Heavy Duty Diesel Truck Design and Commissioning of a Wind Tunnel for...

  14. A New Interpretation of the Scanning Tunneling Microscope Image...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Interpretation of the Scanning Tunneling Microscope Image of Graphite. A New Interpretation of the Scanning Tunneling Microscope Image of Graphite. Abstract: In this work,...

  15. Ivar Giaever, Tunneling, and Superconductors

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your Home as Ready for Summer as You Are?Ivar Giaever, Tunneling,

  16. Iowa High Tunnel Fruit and Vegetable

    E-Print Network [OSTI]

    Goodman, Robert M.

    Introduction to High Tunnels 3 Site Selection 10 Soil Management and Fertility 13 High Tunnel Selection 23 High by a competitive grant from the Marketing and Food Systems Initiative of the Leopold Center for Sustainable Center for Sustainable Agriculture. For more information, go to www.leopold.iastate.edu, or call (515

  17. Quantitative tunneling spectroscopy of nanocrystals

    SciTech Connect (OSTI)

    First, Phillip N; Whetten, Robert L; Schaaff, T Gregory

    2007-05-25T23:59:59.000Z

    The proposed goals of this collaborative work were to systematically characterize the electronic structure and dynamics of 3-dimensional metal and semiconducting nanocrystals using scanning tunneling microscopy/spectroscopy (STM/STS) and ballistic electron emission spectroscopy (BEES). This report describes progress in the spectroscopic work and in the development of methods for creating and characterizing gold nanocrystals. During the grant period, substantial effort also was devoted to the development of epitaxial graphene (EG), a very promising materials system with outstanding potential for nanometer-scale ballistic and coherent devices ("graphene" refers to one atomic layer of graphitic, sp2 -bonded carbon atoms [or more loosely, few layers]). Funding from this DOE grant was critical for the initial development of epitaxial graphene for nanoelectronics

  18. Influence of pair coherence on charge tunneling through a quantum dot connected to a superconducting lead

    E-Print Network [OSTI]

    Domanski, Tadeusz

    Influence of pair coherence on charge tunneling through a quantum dot connected the temperature below T* larger than Tc the single particle states become gradually depleted over a certain energy to a close neighborhood to the Mott insulating state, or because of competition with some other types

  19. SUPERCONDUCTING TUNNEL JUNCTION BOLOMETERS J. CLARKE, G. I. HOFFER and P. L. RICHARDS

    E-Print Network [OSTI]

    Boyer, Edmond

    69 SUPERCONDUCTING TUNNEL JUNCTION BOLOMETERS J. CLARKE, G. I. HOFFER and P. L. RICHARDS DepartmentIioration possible de ces performances. Abstract. 2014 Two new types of superconducting infrared bolometer doped germanium, are widely used as sensitive broadband infrared detectors. Superconducting bolometers

  20. Modeling direct interband tunneling. I. Bulk semiconductors

    SciTech Connect (OSTI)

    Pan, Andrew, E-mail: pandrew@ucla.edu [Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, California 90095 (United States); Chui, Chi On [Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, California 90095 (United States); California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095 (United States)

    2014-08-07T23:59:59.000Z

    Interband tunneling is frequently studied using the semiclassical Kane model, despite uncertainty about its validity. Revisiting the physical basis of this formula, we find that it neglects coupling to other bands and underestimates transverse tunneling. As a result, significant errors can arise at low and high fields for small and large gap materials, respectively. We derive a simple multiband tunneling model to correct these defects analytically without arbitrary parameters. Through extensive comparison with band structure and quantum transport calculations for bulk InGaAs, InAs, and InSb, we probe the accuracy of the Kane and multiband formulas and establish the superiority of the latter. We also show that the nonlocal average electric field should be used when applying either of these models to nonuniform potentials. Our findings are important for efficient analysis and simulation of bulk semiconductor devices involving tunneling.

  1. Josephson scanning tunneling microscopy -- a local and direct probe of the superconducting order parameter

    E-Print Network [OSTI]

    Kimura, Hikari

    2010-01-01T23:59:59.000Z

    Title Josephson scanning tunneling microscopy – a local andthe sample using a novel scanning tunneling microscope (STM)discussed. I. INTRODUCTION Scanning tunneling microscopy (

  2. Le LHC, un tunnel cosmique

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    Et si la lumière au bout du tunnel du LHC était cosmique ? En d?autres termes, qu?est-ce que le LHC peut nous apporter dans la connaissance de l?Univers ? Car la montée en énergie des accélérateurs de particules nous permet de mieux appréhender l?univers primordial, chaud et dense. Mais dans quel sens dit-on que le LHC reproduit des conditions proches du Big bang ? Quelles informations nous apporte-t-il sur le contenu de l?Univers ? La matière noire est-elle détectable au LHC ? L?énergie noire ? Pourquoi l?antimatière accumulée au CERN est-elle si rare dans l?Univers ? Et si le CERN a bâti sa réputation sur l?exploration des forces faibles et fortes qui opèrent au sein des atomes et de leurs noyaux, est-ce que le LHC peut nous apporter des informations sur la force gravitationnelle qui gouverne l?évolution cosmique ? Depuis une trentaine d?années, notre compréhension de l?univers dans ses plus grandes dimensions et l?appréhension de son comportement aux plus petites distances sont intimement liées : en quoi le LHC va-t-il tester expérimentalement cette vision unifiée ? Tout public, entrée libre / Réservations au +41 (0)22 767 76 76

  3. Method of fabricating a solar cell with a tunnel dielectric layer

    DOE Patents [OSTI]

    Dennis, Tim; Harrington, Scott; Manning, Jane; Smith, David; Waldhauer, Ann

    2012-12-18T23:59:59.000Z

    Methods of fabricating solar cells with tunnel dielectric layers are described. Solar cells with tunnel dielectric layers are also described.

  4. Method of fabricating a solar cell with a tunnel dielectric layer

    DOE Patents [OSTI]

    Dennis, Tim; Harrington, Scott; Manning, Jane; Smith, David D; Waldhauer, Ann

    2014-04-29T23:59:59.000Z

    Methods of fabricating solar cells with tunnel dielectric layers are described. Solar cells with tunnel dielectric layers are also described.

  5. Fabrication of magnetic tunnel junctions with epitaxial and textured ferromagnetic layers

    DOE Patents [OSTI]

    Chang, Y. Austin (Middleton, WI); Yang, Jianhua Joshua (Madison, WI)

    2008-11-11T23:59:59.000Z

    This invention relates to magnetic tunnel junctions and methods for making the magnetic tunnel junctions. The magnetic tunnel junctions include a tunnel barrier oxide layer sandwiched between two ferromagnetic layers both of which are epitaxial or textured with respect to the underlying substrate upon which the magnetic tunnel junctions are grown. The magnetic tunnel junctions provide improved magnetic properties, sharper interfaces and few defects.

  6. Axial SiGe Heteronanowire Tunneling Field-Effect Transistors...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    tunneling field-effect transistors (TFETs), where on-state tunneling occurs in the Ge drain section, while off-state leakage is dominated by the Si junction in the source. Our...

  7. Multiscale Modelling of Tunnel Ventilation Flows and Fires 

    E-Print Network [OSTI]

    Colella, Francesco

    Tunnels represent a key part of world transportation system with a role both in people and freight transport. Past events show that fire poses a severe threat to safety in tunnels. Indeed in the past decades over four ...

  8. ACCEPTOR COMPLEXES IN GERMANIUM: SYSTEMS WITH TUNNELING HYDROGEN

    E-Print Network [OSTI]

    Haller, E.E.

    2012-01-01T23:59:59.000Z

    SYSTEMS WIT! l 7UNNELING HYDROGEN E. E. Haller, B. Joos andSYSTEMS WITH TUNNELING HYDROGEN E. E. Haller, B. Joos and L.SYSTEMS WITH TUNNELING HYDROGEN E. E. Haller, B. Jo6s and L.

  9. Design and Construction of a Low Temperature Scanning Tunneling Microscope

    E-Print Network [OSTI]

    Chen, Chi

    2010-10-12T23:59:59.000Z

    A low temperature scanning tunneling microscope (LTSTM) was built that we could use in an ultra high vacuum (UHV) system. The scanning tunneling microscope (STM) was tested on an existing 3He cryostat and calibrated at room, liquid nitrogen...

  10. Chiral tunneling in single and bilayer graphene

    E-Print Network [OSTI]

    T. Tudorovskiy; K. J. A. Reijnders; M. I. Katsnelson

    2011-06-15T23:59:59.000Z

    We review chiral (Klein) tunneling in single-layer and bilayer graphene and present its semiclassical theory, including the Berry phase and the Maslov index. Peculiarities of the chiral tunneling are naturally explained in terms of classical phase space. In a one-dimensional geometry we reduced the original Dirac equation, describing the dynamics of charge carriers in the single layer graphene, to an effective Schr\\"odinger equation with a complex potential. This allowed us to study tunneling in details and obtain analytic formulas. Our predictions are compared with numerical results. We have also demonstrated that, for the case of asymmetric n-p-n junction in single layer graphene, there is total transmission for normal incidence only, side resonances are suppressed.

  11. Electron tunneling studies of Mn12-Acetate

    E-Print Network [OSTI]

    Ma, Lianxi

    2008-10-10T23:59:59.000Z

    ]. . . . . . . . . . . . . . . . 24 10 Frame for rotating the tunneling wires in the PLD chamber during deposition. The two black posts are brass that were wrapped with shrink tubing so that the wires can be attached to them and still be insulated from one another. The two white... copper posts that are made from 0.010” diameter bare copper wires. The tunneling wires are first wrapped around the copper posts and then fixed in position with PbSn solder. Although silver print and silver epoxy have also been used to connect the wires...

  12. Optical realization of two-boson tunneling dynamics

    E-Print Network [OSTI]

    Stefano Longhi

    2011-11-15T23:59:59.000Z

    An optical realization of the tunneling dynamics of two interacting bosons in a double-well potential, based on light transport in a four-core microstructured fiber, is proposed. The optical setting enables to visualize in a purely classical system the entire crossover from Rabi oscillations to correlated pair tunneling and to tunneling of a fragmented pair in the fermionization limit.

  13. Comparison of Ornithopter Wind Tunnel Force Measurements with Free Flight

    E-Print Network [OSTI]

    Fearing, Ron

    Comparison of Ornithopter Wind Tunnel Force Measurements with Free Flight Cameron Rose and Ronald S flight force model from wind tunnel data is a practical approach. In this work, we compare the flight, to measured wind tunnel force and moment values. We compare the two data sets at equilibrium as a metric

  14. Josephson inplane and tunneling currents in bilayer quantum Hall system

    SciTech Connect (OSTI)

    Ezawa, Z. F. [Nishina Center, RIKEN, Saitama 351-0198 (Japan); Tsitsishvili, G. [Georgia Department of Physics, Tbilisi State University, Tbilisi 0179 (Georgia); Sawada, A. [Research Center for Low Temperature and Materials Sciences, Kyoto University, Kyoto 606-8501 (Japan)

    2013-12-04T23:59:59.000Z

    A Bose-Einstein condensation is formed by composite bosons in the quantum Hall state. A composite boson carries the fundamental charge (–e). We investigate Josephson tunneling of such charges in the bilayer quantum Hall system at the total filling ? = 1. We show the existence of the critical current for the tunneling current to be coherent and dissipationless in tunneling experiments with various geometries.

  15. Spin-polarized tunneling in MgO-based tunnel junctions with superconducting electrodes

    E-Print Network [OSTI]

    Schebaum, Oliver

    We prepared magnetic tunnel junctions with one ferromagnetic and one superconducting Al–Si electrode. Pure cobalt electrodes were compared with a Co–Fe–B alloy and the Heusler compound Co[subscript 2]FeAl. The polarization ...

  16. A Historical Evaluation of the U12n Tunnel, Nevada national Security Site, Nye County, Nevada Part 2 of 2

    SciTech Connect (OSTI)

    Drollinger, Harold [DRI; Jones, Robert C [DRI; Bullard, Thomas F [DRI; Ashbaugh, Laurence J [DRI; Griffin, Wayne R

    2011-06-01T23:59:59.000Z

    This report presents a historical evaluation of the U12n Tunnel on the Nevada National Security Site (NNSS) in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12n Tunnel was one of a series of tunnels used for underground nuclear weapons effects tests in Rainier and Aqueduct Mesas. A total of 22 nuclear tests were conducted in the U12n Tunnel from 1967 to 1992. These tests include Midi Mist, Hudson Seal, Diana Mist, Misty North, Husky Ace, Ming Blade, Hybla Fair, Mighty Epic, Diablo Hawk, Miners Iron, Huron Landing, Diamond Ace, Mini Jade, Tomme/Midnight Zephyr, Misty Rain, Mill Yard, Diamond Beech, Middle Note, Misty Echo, Mineral Quarry, Randsburg, and Hunters Trophy. DTRA sponsored all tests except Tomme and Randsburg which were sponsored by the Lawrence Livermore National Laboratory. Midnight Zephyr, sponsored by DTRA, was an add on experiment to the Tomme test. Eleven high explosive tests were also conducted in the tunnel and included a Stemming Plan Test, the Pre-Mill Yard test, the two seismic Non-Proliferation Experiment tests, and seven Dipole Hail tests. The U12n Tunnel complex is composed of the portal and mesa areas, encompassing a total area of approximately 600 acres (240 hectares). Major modifications to the landscape have resulted from four principal activities. These are road construction and maintenance, mining activities related to development of the tunnel complex, site preparation for activities related to testing, and construction of retention ponds. A total of 202 cultural features were recorded for the portal and mesa areas. At the portal area, features relate to the mining, construction, testing, and general everyday operational support activities within the tunnel. These include concrete foundations for buildings, ventilation equipment, air compressors, communications equipment, mining equipment, rail lines, retention ponds to impound tunnel effluent, and storage containers. Features on the mesa above the tunnel generally relate to tunnel ventilation and cooling, borehole drilling, and data recording facilities. Feature types include concrete foundations, instrument cable holes, drill holes, equipment pads, ventilation shafts, and ventilation equipment. The U12n Tunnel complex is eligible to the National Register of Historic Places under criteria a and c, consideration g of 36 CFR Part 60.4 as a historic landscape. Scientific research conducted at the tunnel has made significant contributions to the broad patterns of our history, particularly in regard to the Cold War era that was characterized by competing social, economic, and political ideologies between the former Soviet Union and the United States. The tunnel also possesses distinctive construction and engineering methods for conducting underground nuclear tests. The Desert Research Institute recommends that the U12n Tunnel area be left in place in its current condition and that the U12n Tunnel historic landscape be included in the NNSS monitoring program and monitored for disturbances or alterations on a regular basis.

  17. A Historical Evaluation of the U12n Tunnel, Nevada National Security Site, Nye County, Nevada Part 1

    SciTech Connect (OSTI)

    Drollinger, Harold [DRI; Jones, Robert C [DRI; Bullard, Thomas F [DRI; Ashbaugh, Laurence J [DRI; Griffin, Wayne R [DRI

    2011-06-01T23:59:59.000Z

    This report presents a historical evaluation of the U12n Tunnel on the Nevada National Security Site (NNSS) in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12n Tunnel was one of a series of tunnels used for underground nuclear weapons effects tests in Rainier and Aqueduct Mesas. A total of 22 nuclear tests were conducted in the U12n Tunnel from 1967 to 1992. These tests include Midi Mist, Hudson Seal, Diana Mist, Misty North, Husky Ace, Ming Blade, Hybla Fair, Mighty Epic, Diablo Hawk, Miners Iron, Huron Landing, Diamond Ace, Mini Jade, Tomme/Midnight Zephyr, Misty Rain, Mill Yard, Diamond Beech, Middle Note, Misty Echo, Mineral Quarry, Randsburg, and Hunters Trophy. DTRA sponsored all tests except Tomme and Randsburg which were sponsored by the Lawrence Livermore National Laboratory. Midnight Zephyr, sponsored by DTRA, was an add on experiment to the Tomme test. Eleven high explosive tests were also conducted in the tunnel and included a Stemming Plan Test, the Pre-Mill Yard test, the two seismic Non-Proliferation Experiment tests, and seven Dipole Hail tests. The U12n Tunnel complex is composed of the portal and mesa areas, encompassing a total area of approximately 600 acres (240 hectares). Major modifications to the landscape have resulted from four principal activities. These are road construction and maintenance, mining activities related to development of the tunnel complex, site preparation for activities related to testing, and construction of retention ponds. A total of 202 cultural features were recorded for the portal and mesa areas. At the portal area, features relate to the mining, construction, testing, and general everyday operational support activities within the tunnel. These include concrete foundations for buildings, ventilation equipment, air compressors, communications equipment, mining equipment, rail lines, retention ponds to impound tunnel effluent, and storage containers. Features on the mesa above the tunnel generally relate to tunnel ventilation and cooling, borehole drilling, and data recording facilities. Feature types include concrete foundations, instrument cable holes, drill holes, equipment pads, ventilation shafts, and ventilation equipment. The U12n Tunnel complex is eligible to the National Register of Historic Places under criteria a and c, consideration g of 36 CFR Part 60.4 as a historic landscape. Scientific research conducted at the tunnel has made significant contributions to the broad patterns of our history, particularly in regard to the Cold War era that was characterized by competing social, economic, and political ideologies between the former Soviet Union and the United States. The tunnel also possesses distinctive construction and engineering methods for conducting underground nuclear tests. The Desert Research Institute recommends that the U12n Tunnel area be left in place in its current condition and that the U12n Tunnel historic landscape be included in the NNSS monitoring program and monitored for disturbances or alterations on a regular basis.

  18. DNA Sequencing via Electron Tunneling Michael Zwolak

    E-Print Network [OSTI]

    Zwolak, Michael

    DNA Sequencing via Electron Tunneling Michael Zwolak Department of Physics Oregon State University-cost DNA sequencing methods would revolutionize medicine: a person could have his/her full genome sequenced of "personalized medicine" is hampered today by the high cost and slow speed of DNA sequencing methods. We

  19. Inelastic Tunneling Spectroscopy in Unconventional Superconductors

    E-Print Network [OSTI]

    Inelastic Tunneling Spectroscopy in Unconventional Superconductors Molecular Vibration and Single Superconductors ­ p.1/13 #12;Old Results R.C. Jaklevic and J. Lambe, Phys. Rev. Lett. 17, 1139-1140 (1966 in Unconventional Superconductors ­ p.2/13 #12;STM observation of local inelastic mode B.C. Stipe, M.A Rezaei, and W

  20. Vector particles tunneling from BTZ black holes

    E-Print Network [OSTI]

    Ge-Rui Chen; Shiwei Zhou; Yong-Chang Huang

    2014-09-21T23:59:59.000Z

    In this paper we investigate vector particles' Hawking radiation from a BTZ black hole. By applying the WKB approximation and the Hamilton-Jacobi Ansatz to the Proca equation, we obtain the tunneling spectrum of vector particles. The expected Hawking temperature is recovered.

  1. Scanning Josephson Tunneling Microscopy of Single Crystal Bi2Sr2CaCu2O8+delta with a Conventional Superconducting Tip

    E-Print Network [OSTI]

    Kimura, H.

    2010-01-01T23:59:59.000Z

    Title) Scanning Josephson Tunneling Microscopy of Singlea conventional superconducting scanning tunneling microscopeabstract} (Body) Remarkable scanning tunneling microscopy (

  2. Simulation of Enhanced-Explosive Devices in Chambers and Tunnels

    SciTech Connect (OSTI)

    Bell, J B; Kuhl, A L; Beckner, V E

    2007-06-05T23:59:59.000Z

    Introduction: Shock-dispersed fuel (SDF) explosives use a small chemical charge to disperse a combustible fuel that burns in the post-detonation environment. The energy released in the combustion process has the potential for generating higher pressures and temperatures than conventional explosives. However, the development of these types of novel explosive systems requires a detailed understanding of all of the modes of energy release. Objective: The objective of this project is develop a simulation capability for predicting explosion and combustion phase of SDF charges and apply that capability to quantifying the behavior of these types of explosives. Methodology: We approximate the dynamics of an SDF charge using high Reynolds number, fast chemistry model that effectively captures the thermodynamic behavior of SDF charges and accurately models the key modes of energy release. The overall computational model is combined with Adaptive Mesh Refinement (AMR) , implemented in a parallel adaptive framework suited to the massively parallel computer systems. Results: We have developed a multiphase version of the model and used it to simulate an SDF charge in which the dispersed fuel is aluminum flakes. Flow visualizations show that the combustion field is turbulent for the chamber and tunnel cases studied. During the 3 milli-seconds of simulation, over 90% of the Al fuel was consumed for the chamber case, while about 40% was consumed in the tunnel case in agreement with Al-SDF experiments. Significance to DoD: DoD has a requirement to develop enhanced energetic materials to support future military systems. The SDF charges described here utilize the combustion mechanism to increase energy per gram of fuel by a factor of 7 to 10 over conventional (detonating) charges, and increase the temperature of the explosion cloud to 2,000-4,000 K (depending on the SDF fuel). Accurate numerical simulation of such SDF explosions allows one to understand the energy release mechanism, and thereby design full-scale systems with greatly improved explosive efficiency.

  3. Scanning tunneling microscope assembly, reactor, and system

    DOE Patents [OSTI]

    Tao, Feng; Salmeron, Miquel; Somorjai, Gabor A

    2014-11-18T23:59:59.000Z

    An embodiment of a scanning tunneling microscope (STM) reactor includes a pressure vessel, an STM assembly, and three spring coupling objects. The pressure vessel includes a sealable port, an interior, and an exterior. An embodiment of an STM system includes a vacuum chamber, an STM reactor, and three springs. The three springs couple the STM reactor to the vacuum chamber and are operable to suspend the scanning tunneling microscope reactor within the interior of the vacuum chamber during operation of the STM reactor. An embodiment of an STM assembly includes a coarse displacement arrangement, a piezoelectric fine displacement scanning tube coupled to the coarse displacement arrangement, and a receiver. The piezoelectric fine displacement scanning tube is coupled to the coarse displacement arrangement. The receiver is coupled to the piezoelectric scanning tube and is operable to receive a tip holder, and the tip holder is operable to receive a tip.

  4. The Emergent Universe scheme and tunneling

    SciTech Connect (OSTI)

    Labraña, Pedro [Departamento de Física, Universidad del Bío-Bío, Avenida Collao 1202, Casilla 5-C, Concepción, Chile and Departament d'Estructura i Constituents de la Matèria and Institut de Ciències del Cosmos, Universitat (Spain)

    2014-07-23T23:59:59.000Z

    We present an alternative scheme for an Emergent Universe scenario, developed previously in Phys. Rev. D 86, 083524 (2012), where the universe is initially in a static state supported by a scalar field located in a false vacuum. The universe begins to evolve when, by quantum tunneling, the scalar field decays into a state of true vacuum. The Emergent Universe models are interesting since they provide specific examples of non-singular inflationary universes.

  5. Influence of growth and annealing conditions on low-frequency magnetic 1/f noise in MgO magnetic tunnel junctions

    SciTech Connect (OSTI)

    Feng Jiafeng; Diao Zhu; Kurt, Huseyin; Singh, A.; Coey, J. M. D. [CRANN and School of Physics, Trinity College, Dublin 2 (Ireland); Stearrett, Ryan; Nowak, Edmund R. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States)

    2012-11-01T23:59:59.000Z

    Magnetic 1/f noise is compared in magnetic tunnel junctions with electron-beam evaporated and sputtered MgO tunnel barriers in the annealing temperature range 350 - 425 Degree-Sign C. The variation of the magnetic noise parameter ({alpha}{sub mag}) of the reference layer with annealing temperature mainly reflects the variation of the pinning effect of the exchange-bias layer. A reduction in {alpha}{sub mag} with bias is associated with the bias dependence of the tunneling magnetoresistance. The related magnetic losses are parameterized by a phase lag {epsilon}, which is nearly independent of bias especially below 100 mV. The similar changes in magnetic noise with annealing temperature and barrier thickness for two types of MgO magnetic tunnel junctions indicate that the barrier layer quality does not affect the magnetic losses in the reference layer.

  6. Time Evolution of Tunneling in Thermal Medium -- Environment-driven Excited Tunneling --

    E-Print Network [OSTI]

    Sh. Matsumoto; M. Yoshimura

    2003-07-18T23:59:59.000Z

    Time evolution of tunneling phenomena proceeding in thermal medium is studied using a standard model of environment interaction. A semiclassical probability formula for the particle motion in a metastable state of one dimensional system put in thermal medium is combined with the formula of quantum penetration factor through a potential barrier, to derive the tunneling rate in medium. Effect of environment, its influence on time evolution in particular, is clarified in a real-time formalism. A nonlinear resonance effect is shown to enhance the tunneling rate at finite times of order $2/\\eta $, with $\\eta $ the friction coefficient. In the linear approximation this effect has relevance to the parametric resonance. This effect enhances the possibility of early termination of the cosmological phase transition much prior to the typical Hubble time.

  7. Interference effects in tunnelling of "cat" wave packet states

    E-Print Network [OSTI]

    D. Sokolovski

    2015-02-26T23:59:59.000Z

    We analyse tunnelling of a single particle, whose initial state is given by a superposition of spatially separated wave packet modes. It is shown that "pile up" of different components the scatterer may change the tunnelling probabilities, making such states a convenient tool for probing the barrier's scattering times. Interference effects arising in resonance tunnelling in are studied in detail. The analysis allows us to gain further insight into the origin of interference effects in scattering of several identical particles.

  8. Calculation of tunneling rates across a barrier with continuous potential

    E-Print Network [OSTI]

    Sina Khorasani

    2011-04-10T23:59:59.000Z

    Here, approximate, but accurate expressions for calculation of wavefunctions and tunneling rates are obtained using the method of uniform asymptotic expansion.

  9. Tunneling in Polymer Quantization and the Quantum Zeno Effect

    E-Print Network [OSTI]

    Durmus Ali Demir; Ozan Sargin

    2014-09-25T23:59:59.000Z

    As an application of the polymer quantization scheme, in this work we investigate the one dimensional quantum mechanical tunneling phenomenon from the perspective of polymer representation of a non-relativistic point particle and derive the transmission and reflection coefficients. Since any tunneling phenomenon inevitably evokes a tunneling time we attempt an analytical calculation of tunneling times by defining an operator well suited in discrete spatial geometry. The results that we come up with hint at appearance of the Quantum Zeno Effect in polymer framework.

  10. DEVELOPMENT AND APPLICATION OF A FAST-RUNNING TOOL TO CHARACTERIZE SHOCK DAMAGE WITHIN TUNNEL STRUCTURES

    SciTech Connect (OSTI)

    Glascoe, L; Morris, J; Glenn, L; Krnjajic, M

    2009-03-31T23:59:59.000Z

    Successful but time-intensive use of high-fidelity computational capabilities for shock loading events and resultant effects on and within enclosed structures, e.g., tunnels, has led to an interest in developing more expedient methods of analysis. While several tools are currently available for the general study of the failure of structures under dynamic shock loads at a distance, presented are a pair of statistics- and physics-based tools that can be used to differentiate different types of damage (e.g., breach versus yield) as well as quantify the amount of damage within tunnels for loads close-in and with standoff. Use of such faster running tools allows for scoping and planning of more detailed model and test analysis and provides a way to address parametric sensitivity over a large multivariate space.

  11. Penn Small Water Tunnel | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to: navigation, searchOfRoseConcernsCompanyPCN TechnologyFrance) JumpPearsonCollegeTunnel

  12. Bifurcation tunneling dynamics in the water trimer Frank N. Keutscha)

    E-Print Network [OSTI]

    Cohen, Ronald C.

    details of the hydrogen bond tunneling dynamics in the water trimer through excitation of intermolecular­6 and for a detailed molecular description of the associated hydrogen bond rear- rangement dynamics.7­35 Ultimately, weBifurcation tunneling dynamics in the water trimer Frank N. Keutscha) and Richard J. Saykallyb

  13. TBM tunnel friction values for the Grizzly Powerhouse Project

    SciTech Connect (OSTI)

    Stutsman, R.D. [Ensign & Buckley Consulting Engineers, Larkspur, CA (United States); Rothfuss, B.D. [Pacific Gas and Electric Co., San Francisco, CA (United States)

    1995-12-31T23:59:59.000Z

    Tunnel boring machine (TBM) driven water conveyance tunnels are becoming increasingly more common. Despite advances in tunnel engineering and construction technology, hydraulic performance data for TBM driven tunnels remains relatively unavailable. At the Grizzly Powerhouse Project, the TBM driven water conveyance tunnel was designed using friction coefficients developed from a previous PG&E project. A range of coefficients were selected to bound the possible hydraulic performance variations of the water conveyance system. These friction coefficients, along with the water conveyance systems characteristics, and expected turbine characteristics, were used in a hydraulic transient analysis to determine the expected system pressure fluctuations, and surge chamber performance. During startup test data, these performance characteristics were measured to allow comparison to the original design assumptions. During construction of the tunnel, plaster casts were made of the actual excavated tunnel unlined and fiber reinforced shotcrete lined surfaces. These castings were used to measure absolute roughness of the surfaces so that a friction coefficient could be developed using the Moody diagram and compare them against the design values. This paper compares the assumed frictional coefficient with computed coefficients from headlosses measured during startup testing, and plaster cast measurement calculations. In addition, a comparison of coefficients will be presented for an other TBM driven water conveyance tunnel constructed in the 1980`s.

  14. Radio-frequency scanning tunnelling microscopy U. Kemiktarak1

    E-Print Network [OSTI]

    LETTERS Radio-frequency scanning tunnelling microscopy U. Kemiktarak1 , T. Ndukum3 , K. C. Schwab3 measurementsinmesoscopicelectronicsandmechanics. Broadband noise measurements across the tunnel junction using this radio-frequency STM available from nanoscale optical and electrical displacement detection tech- niques, and the radio

  15. Tunneling of Graphene Massive Dirac Fermions through a Double Barrier

    E-Print Network [OSTI]

    Hocine Bahlouli; El Bouazzaoui Choubabi; Ahmed Jellal; Miloud Mekkaoui

    2011-10-04T23:59:59.000Z

    We study the tunneling of Dirac fermions in graphene through a double barrier potential allowing the carriers to have an effective mass inside the barrier as generated by a lattice miss-match with the boron nitride substrate. The consequences of this gap opening on the transmission are investigated. The realization of resonant tunneling conditions is also analyzed.

  16. Long-term behaviour of twin tunnels in London clay

    E-Print Network [OSTI]

    Laver, Richard George

    2011-03-15T23:59:59.000Z

    Offset of maximum horizontal displacement from tunnel cen- treline ARS Coefficient in relative settlement equation, see equation (8.19) AT Cross-sectional area of tunnel Atw Multiple of i defining extent of full trough width B Pore pressure coefficient...

  17. High Tunnel Crop Production Tips Lewis W. Jett

    E-Print Network [OSTI]

    Goodman, Robert M.

    . Specifically, high tunnels are passively vented, solar greenhouses covered with 1-2 layers of greenhouse perpendicular (at right angles) to the prevailing winds on your farm. Generally, this is a north-south direction supplemental heating systems? High tunnels should be designed and managed as passively vented and solar heated

  18. Computational Role of Multiqubit Tunneling in a Quantum Annealer

    E-Print Network [OSTI]

    Sergio Boixo; Vadim N. Smelyanskiy; Alireza Shabani; Sergei V. Isakov; Mark Dykman; Vasil S. Denchev; Mohammad Amin; Anatoly Smirnov; Masoud Mohseni; Hartmut Neven

    2015-02-20T23:59:59.000Z

    Quantum tunneling, a phenomenon in which a quantum state traverses energy barriers above the energy of the state itself, has been hypothesized as an advantageous physical resource for optimization. Here we show that multiqubit tunneling plays a computational role in a currently available, albeit noisy, programmable quantum annealer. We develop a non-perturbative theory of open quantum dynamics under realistic noise characteristics predicting the rate of many-body dissipative quantum tunneling. We devise a computational primitive with 16 qubits where quantum evolutions enable tunneling to the global minimum while the corresponding classical paths are trapped in a false minimum. Furthermore, we experimentally demonstrate that quantum tunneling can outperform thermal hopping along classical paths for problems with up to 200 qubits containing the computational primitive. Our results indicate that many-body quantum phenomena could be used for finding better solutions to hard optimization problems.

  19. Tunnel-injection GaN quantum dot ultraviolet light-emitting diodes

    SciTech Connect (OSTI)

    Verma, Jai; Kandaswamy, Prem Kumar; Protasenko, Vladimir; Verma, Amit; Grace Xing, Huili; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)] [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)

    2013-01-28T23:59:59.000Z

    We demonstrate a GaN quantum dot ultraviolet light-emitting diode that uses tunnel injection of carriers through AlN barriers into the active region. The quantum dot heterostructure is grown by molecular beam epitaxy on AlN templates. The large lattice mismatch between GaN and AlN favors the formation of GaN quantum dots in the Stranski-Krastanov growth mode. Carrier injection by tunneling can mitigate losses incurred in hot-carrier injection in light emitting heterostructures. To achieve tunnel injection, relatively low composition AlGaN is used for n- and p-type layers to simultaneously take advantage of effective band alignment and efficient doping. The small height of the quantum dots results in short-wavelength emission and are simultaneously an effective tool to fight the reduction of oscillator strength from quantum-confined Stark effect due to polarization fields. The strong quantum confinement results in room-temperature electroluminescence peaks at 261 and 340 nm, well above the 365 nm bandgap of bulk GaN. The demonstration opens the doorway to exploit many varied features of quantum dot physics to realize high-efficiency short-wavelength light sources.

  20. Instanton solutions mediating tunneling between the degenerate vacua in curved space

    SciTech Connect (OSTI)

    Lee, Bum-Hoon; Lee, Wonwoo [Department of Physics and BK21 Division, and Center for Quantum Spacetime, Sogang University, Seoul 121-742 (Korea, Republic of); Lee, Chul H. [Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of); Oh, Changheon [Department of Physics, Hanyang University, Seoul 133-791 (Korea, Republic of); Principal Researcher Center, Technovation Partners, Seoul 135-824 (Korea, Republic of)

    2010-07-15T23:59:59.000Z

    We investigate the instanton solution between the degenerate vacua in curved space. We show that there exist O(4)-symmetric solutions not only in de Sitter but also in both flat and anti-de Sitter space. The geometry of the new type of solutions is finite and preserves the Z{sub 2} symmetry. The nontrivial solution corresponding to the tunneling is possible only if gravity is taken into account. The numerical solutions as well as the analytic computations using the thin-wall approximation are presented. We expect that these solutions do not have any negative mode as in the instanton solution.

  1. Massless neutrino oscillations via quantum tunneling

    E-Print Network [OSTI]

    Zhao, Hai-Long

    2015-01-01T23:59:59.000Z

    In order for different kinds of neutrino to transform into each other, the eigenvalues of energy of neutrino must be different. In the present theory of neutrino oscillations, this is guaranteed by the mass differences between the different eigenstates of neutrino. Thus neutrino cannot oscillate if it is massless. We suggest an explanation for neutrino oscillations by analogy with the oscillation of quantum two-state system, where the flipping of one state into the other may be regarded as a process of quantum tunneling and the required energy difference between the two eigenstates comes from the barrier potential energy. So neutrino with vanishing mass can also oscillate. One of the advantages of the explanation is that neutrino can still be described with Weyl equation within the framework of standard model.

  2. Massless neutrino oscillations via quantum tunneling

    E-Print Network [OSTI]

    Hai-Long Zhao

    2015-02-03T23:59:59.000Z

    In order for different kinds of neutrino to transform into each other, the eigenvalues of energy of neutrino must be different. In the present theory of neutrino oscillations, this is guaranteed by the mass differences between the different eigenstates of neutrino. Thus neutrino cannot oscillate if it is massless. We suggest an explanation for neutrino oscillations by analogy with the oscillation of quantum two-state system, where the flipping of one state into the other may be regarded as a process of quantum tunneling and the required energy difference between the two eigenstates comes from the barrier potential energy. So neutrino with vanishing mass can also oscillate. One of the advantages of the explanation is that neutrino can still be described with Weyl equation within the framework of standard model.

  3. Wavevector Selective Metasurfaces and Tunnel Vision Filters

    E-Print Network [OSTI]

    Fedotov, Vassili A; Walther, Markus; Perino, Mauro; Papasimakis, Nikitas; Zheludev, Nikolay I

    2015-01-01T23:59:59.000Z

    Metasurfaces offer unprecedented flexibility in the design and control of light propagation, replacing bulk optical components and exhibiting exotic optical effects. One of the basic properties of the metasurfaces, which renders them as frequency selective surfaces, is the ability to transmit or reflect radiation within a narrow spectral band that can be engineered on demand. Here we introduce and demonstrate experimentally in the THz domain the concept of wavevector selective surfaces -- metasurfaces transparent only within a narrow range of light propagation directions operating effectively as tunnel vision filters. Practical implementations of the new concept include applications in wavefront manipulation, observational instruments, vision and free-space communication in light-scattering environments, as well as passive camouflage.

  4. Resonant tunneling of fluctuation Cooper pairs

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Galda, Alexey; Mel'nikov, A. S.; Vinokur, V. M.

    2015-02-09T23:59:59.000Z

    Superconducting fluctuations have proved to be an irreplaceable source of information about microscopic and macroscopic material parameters that could be inferred from the experiment. According to common wisdom, the effect of thermodynamic fluctuations in the vicinity of the superconducting transition temperature, Tc, is to round off all of the sharp corners and discontinuities, which otherwise would have been expected to occur at Tc. Here we report the current spikes due to radiation-induced resonant tunneling of fluctuation Cooper pairs between two superconductors which grow even sharper and more pronounced upon approach to Tc. This striking effect offers an unprecedented tool formore »direct measurements of fluctuation Cooper pair lifetime, which is key to our understanding of the fluctuation regime, most notably to nature of the pseudogap state in high-temperature superconductors. Our finding marks a radical departure from the conventional view of superconducting fluctuations as a blurring and rounding phenomenon.« less

  5. Neuroreceptor Activation by Vibration-Assisted Tunneling

    E-Print Network [OSTI]

    Hoehn, Ross D; Neven, Hartmut; Kais, Sabre

    2015-01-01T23:59:59.000Z

    G protein-coupled receptors (GPCRs) constitute a large family of receptor proteins that sense molecular signals on the exterior of a cell and activate signal transduction pathways within the cell. Modeling how an agonist activates such a receptor is fundamental for an understanding of a wide variety of physiological processes and it is of tremendous value for pharmacology and drug design. Inelastic electron tunneling spectroscopy (IETS) has been proposed as a model for the mechanism by which olfactory GPCRs are activated by a bound agonist. We apply this hypothesis to GPCRs within the mammalian nervous system using quantum chemical modeling. We found that non-endogenous agonists of the serotonin receptor share a particular IET spectral aspect both amongst each other and with the serotonin molecule: a peak whose intensity scales with the known agonist potencies. We propose an experiential validation of this model by utilizing lysergic acid dimethylamide (DAM-57), an ergot derivative, and its deuterated isotopo...

  6. Modeling direct interband tunneling. II. Lower-dimensional structures

    SciTech Connect (OSTI)

    Pan, Andrew, E-mail: pandrew@ucla.edu [Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, California 90095 (United States); Chui, Chi On [Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, California 90095 (United States); California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095 (United States)

    2014-08-07T23:59:59.000Z

    We investigate the applicability of the two-band Hamiltonian and the widely used Kane analytical formula to interband tunneling along unconfined directions in nanostructures. Through comparisons with k·p and tight-binding calculations and quantum transport simulations, we find that the primary correction is the change in effective band gap. For both constant fields and realistic tunnel field-effect transistors, dimensionally consistent band gap scaling of the Kane formula allows analytical and numerical device simulations to approximate non-equilibrium Green's function current characteristics without arbitrary fitting. This allows efficient first-order calibration of semiclassical models for interband tunneling in nanodevices.

  7. Computational modeling of electrophotonics nanomaterials: Tunneling in double quantum dots

    SciTech Connect (OSTI)

    Vlahovic, Branislav, E-mail: vlahovic@nccu.edu; Filikhin, Igor, E-mail: vlahovic@nccu.edu [Department of Physics, North Carolina Central University, 1801 Fayetteville Street, Durham, North Carolina 27707 (United States)

    2014-10-06T23:59:59.000Z

    Single electron localization and tunneling in double quantum dots (DQD) and rings (DQR) and in particular the localized-delocalized states and their spectral distributions are considered in dependence on the geometry of the DQDs (DQRs). The effect of violation of symmetry of DQDs geometry on the tunneling is studied in details. The cases of regular and chaotic geometries are considered. It will be shown that a small violation of symmetry drastically affects localization of electron and that anti-crossing of the levels is the mechanism of tunneling between the localized and delocalized states in DQRs.

  8. Response of continuous pipelines to tunnel induced ground deformations

    E-Print Network [OSTI]

    Ieronymaki, Evangelia S

    2011-01-01T23:59:59.000Z

    This thesis develops analytical solutions for estimating the bending moments and axial loads in a buried pipeline due to ground movements caused by tunnel construction in soft ground. The solutions combine closed-form, ...

  9. Hawking Radiation as Tunneling: the D-dimensional rotating case

    E-Print Network [OSTI]

    M. Nadalini; L. Vanzo; S. Zerbini

    2005-11-24T23:59:59.000Z

    The tunneling method for the Hawking radiation is revisited and applied to the $D$ dimensional rotating case. Emphasis is given to covariance of results. Certain ambiguities afflicting the procedure are resolved.

  10. Hydrogen adsorption on Ru(001) studied by Scanning Tunneling Microscopy

    E-Print Network [OSTI]

    Tatarkhanov, Mous; Rose, Franck; Fomin, Evgeny; Ogletree, D. Frank; Salmeron, Miquel

    2008-01-01T23:59:59.000Z

    001) and first hydrogen adsorption structure with (?3×?3)R30Hydrogen adsorption on Ru(001) studied by Scanning TunnelingCA 94720 Keywords: STM, Adsorption, Dissociation; Hydrogen,

  11. Effect of anisotropy in ground movements caused by tunnelling

    E-Print Network [OSTI]

    Zymnis, Despina Maria

    This paper presents closed-form analytical solutions for estimating far-field ground deformations caused by shallow tunnelling in a linear elastic soil mass with cross-anisotropic stiffness properties. The solutions describe ...

  12. Effect of existing building on tunneling-induced ground movements

    E-Print Network [OSTI]

    Law, Rachel Hoi-chee

    2012-01-01T23:59:59.000Z

    The goal of this thesis is to assess the influence of an existing structure on tunneling-induced ground movements. This is accomplished through 2D numerical simulations that are compared with similar prior studies reported ...

  13. Scanning Tunneling Microscopy and Theoretical Study of Water...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and Theoretical Study of Water Adsorption on Fe3O4: Implications for Catalysis. Scanning Tunneling Microscopy and Theoretical Study of Water Adsorption on Fe3O4: Implications...

  14. Computational design and analysis of flatback airfoil wind tunnel experiment.

    SciTech Connect (OSTI)

    Mayda, Edward A. (University of California, Davis, CA); van Dam, C.P. (University of California, Davis, CA); Chao, David D. (University of California, Davis, CA); Berg, Dale E.

    2008-03-01T23:59:59.000Z

    A computational fluid dynamics study of thick wind turbine section shapes in the test section of the UC Davis wind tunnel at a chord Reynolds number of one million is presented. The goals of this study are to validate standard wind tunnel wall corrections for high solid blockage conditions and to reaffirm the favorable effect of a blunt trailing edge or flatback on the performance characteristics of a representative thick airfoil shape prior to building the wind tunnel models and conducting the experiment. The numerical simulations prove the standard wind tunnel corrections to be largely valid for the proposed test of 40% maximum thickness to chord ratio airfoils at a solid blockage ratio of 10%. Comparison of the computed lift characteristics of a sharp trailing edge baseline airfoil and derived flatback airfoils reaffirms the earlier observed trend of reduced sensitivity to surface contamination with increasing trailing edge thickness.

  15. Resonant spin tunneling in randomly oriented nanospheres of Mn?? acetate

    SciTech Connect (OSTI)

    Lendinez, S. [Univ. de Barcelona, Barcelona, Spain (Europe); Billinge, S. J. L. [Columbia Univ., New York, NY (United States); Zarzuela, R. [Univ. de Barcelona, Barcelona, Spain (Europe); Tejada, J. [Univ. de Barcelona, Barcelona, Spain (Europe); Terban, M. W. [Columbia Univ., New York, NY (United States); Espin, J. [Univ. Autonoma Barcelona, Barcelona, Spain (Europe); Imaz, I. [Univ. Autonoma Barcelona, Barcelona, Spain (Europe); Maspoch, D. [Univ. Autonoma Barcelona, Barcelona, Spain (Europe); Chudnovsky, E. M. [City Univ. of New York, Bronx, NY (United States)

    2015-01-01T23:59:59.000Z

    We report measurements and theoretical analysis of resonant spin tunneling in randomly oriented nanospheres of a molecular magnet. Amorphous nanospheres of Mn?? acetate have been fabricated and characterized by chemical, infrared, TEM, X-ray, and magnetic methods. Magnetic measurements have revealed sharp tunneling peaks in the field derivative of the magnetization that occur at the typical resonant field values for the Mn?? acetate crystal in the field parallel to the easy axis.Theoretical analysis is provided that explains these observations. We argue that resonant spin tunneling in a molecular magnet can be established in a powder sample, without the need for a single crystal and without aligning the easy magnetization axes of the molecules. This is confirmed by re-analyzing the old data on a powdered sample of non-oriented micron-size crystals of Mn?? acetate. Our findings can greatly simplify the selection of candidates for quantum spin tunneling among newly synthesized molecular magnets.

  16. Vacuum gaps with small tunnel currents at large electric field...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Vacuum gaps with small tunnel currents at large electric field and its potential applications for energy storage, charge storage and power supplies. Friday, May 27, 2011 - 4:00pm...

  17. Tunneling from super- to normal-deformed minima in nuclei.

    SciTech Connect (OSTI)

    Khoo, T. L.

    1998-01-08T23:59:59.000Z

    An excited minimum, or false vacuum, gives rise to a highly elongated superdeformed (SD) nucleus. A brief review of superdeformation is given, with emphasis on the tunneling from the false to the true vacuum, which occurs in the feeding and decay of SD bands. During the feeding process the tunneling is between hot states, while in the decay it is from a cold to a hot state. The {gamma} spectra connecting SD and normal-deformed (ND) states provide information on several physics issues: the decay mechanism; the spin/parity quantum numbers, energies and microscopic structures of SD bands; the origin of identical SD bands; the quenching of pairing with excitation energy; and the chaoticity of excited ND states at 2.5-5 MeV. Other examples of tunneling in nuclei, which are briefly described, include the possible role of tunneling in {Delta}I = 4 bifurcation in SD bands, sub-barrier fusion and proton emitters.

  18. UNSTEADY WIND TUNNEL CONTROL OF STABILITY AND TRANSITION

    E-Print Network [OSTI]

    Fluid Mechanics #12;UNSTEADY WIND TUNNEL 3-D BOUNDARY LAYERS · CROSSFLOW ­ Swept Wing ­ Rotating Disk INSTABILITY MECHANISMS · Leading-edge contamination · Streamwise instabilities · Crossflow instabilities AT ASU · BASIC CROSSFLOW EXPERIMENT with Ray Dagenhart 1988, 1989 isolate crossflow mechanism from T

  19. annular josephson tunnel: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of an order of magnitude and the corresponding lifetime of about seven decades. R. Yamapi; G. Filatrella 2014-06-24 458 Emergent Universe by Tunneling HEP - Theory (arXiv)...

  20. One Hair Postulate for Hawking Radiation as Tunneling Process

    E-Print Network [OSTI]

    H. Dong; Qing-yu Cai; X. F. Liu; C. P. Sun

    2009-07-13T23:59:59.000Z

    For Hawking radiation, treated as a tunneling process, the no-hair theorem of black hole together with the law of energy conservation is utilized to postulate that the tunneling rate only depends on the external qualities (e.g., the mass for the Schwarzschild black hole) and the energy of the radiated particle. This postulate is justified by the WKB approximation for calculating the tunneling probability. Based on this postulate, a general formula for the tunneling probability is derived without referring to the concrete form of black hole metric. This formula implies an intrinsic correlation between the successive processes of the black hole radiation of two or more particles. It also suggests a kind of entropy conservation and thus resolves the puzzle of black hole information loss in some sense.

  1. Hawking Radiation as Tunnelling in Static Black Holes

    E-Print Network [OSTI]

    Wenbiao Liu

    2005-12-16T23:59:59.000Z

    Hawking radiation can usefully be viewed as a semi-classical tunnelling process that originates at the black hole horizon. The conservation of energy implies the effect of self-gravitation. For a static black hole, a generalized Painleve coordinate system is introduced, and Hawking radiation as tunnelling under the effect of self-gravitation is investigated. The corrected radiation is consistent with the underlying unitary theory.

  2. Hawking Radiation as Tunnelling in Static Black Holes

    E-Print Network [OSTI]

    Liu, W

    2005-01-01T23:59:59.000Z

    Hawking radiation can usefully be viewed as a semi-classical tunnelling process that originates at the black hole horizon. The conservation of energy implies the effect of self-gravitation. For a static black hole, a generalized Painleve coordinate system is introduced, and Hawking radiation as tunnelling under the effect of self-gravitation is investigated. The corrected radiation is consistent with the underlying unitary theory.

  3. Fabrication of a gated gallium arsenide heterostructure resonant tunneling diode 

    E-Print Network [OSTI]

    Kinard, William Brian

    1989-01-01T23:59:59.000Z

    ) William Brian Kinard, B. S, Texas A&M University Chair of Advisory Committee: Mark H. Weichold The objective of this research was to design and fabricate a device capable of electrically contrulhng current through a vertical resonant tunneling diode.... Addi- tionally, this modulation of current must not aB'ect the normal cperation of the resonant tunneling diode such as shifting resonant bias. Device arrays of various sizes were successfully 1'abricated for the first time utilizing unique...

  4. Computational Role of Collective Tunneling in a Quantum Annealer

    E-Print Network [OSTI]

    Sergio Boixo; Vadim N. Smelyanskiy; Alireza Shabani; Sergei V. Isakov; Mark Dykman; Vasil S. Denchev; Mohammad Amin; Anatoly Smirnov; Masoud Mohseni; Hartmut Neven

    2015-02-19T23:59:59.000Z

    Quantum tunneling is a phenomenon in which a quantum state traverses energy barriers above the energy of the state itself. Tunneling has been hypothesized as an advantageous physical resource for optimization. Here we present the first experimental evidence of a computational role of multiqubit quantum tunneling in the evolution of a programmable quantum annealer. We develop a theoretical model based on a NIBA Quantum Master Equation to describe the multiqubit dissipative tunneling effects under the complex noise characteristics of such quantum devices. We start by considering a computational primitive, an optimization problem consisting of just one global and one false minimum. The quantum evolutions enable tunneling to the global minimum while the corresponding classical paths are trapped in a false minimum. In our study the non-convex potentials are realized by frustrated networks of qubit clusters with strong intra-cluster coupling. We show that the collective effect of the quantum environment is suppressed in the "critical" phase during the evolution where quantum tunneling "decides" the right path to solution. In a later stage dissipation facilitates the multiqubit tunneling leading to the solution state. The predictions of the model accurately describe the experimental data from the D-Wave Two quantum annealer at NASA Ames. In our computational primitive the temperature dependence of the probability of success in the quantum model is opposite to that of the classical paths with thermal hopping. Specifically, we provide an analysis of an optimization problem with sixteen qubits, demonstrating eight qubit tunneling that increases success probabilities. Furthermore, we report results for larger problems with up to 200 qubits that contain the primitive as subproblems.

  5. Theory of Extrinsic and Intrinsic Tunnelling in Cuprate Superconductors

    E-Print Network [OSTI]

    J. Beanland; A. S. Alexandrov

    2010-05-03T23:59:59.000Z

    A theory capable of explaining intrinsic and extrinsic tunnelling conductance in underdoped cuprates has been devised that accounts for the existence of two energy scales, their temperature and doping dependencies. The asymmetry and inhomogeneity seen in extrinsic (normal metal - superconductor (NS)) tunnelling and the normal-state gapped intrinsic (SS) conductance is explained, as well as the superconducting gap and normal state pseudogap and the temperature dependence of the full gap.

  6. High Pressure Scanning Tunneling Microscopy and High Pressure X-ray Photoemission Spectroscopy Studies of Adsorbate Structure, Composition and Mobility during Catalytic Reactions on A Model Single Crystal

    E-Print Network [OSTI]

    Montano, M.O.

    2006-01-01T23:59:59.000Z

    Guntherodt, H. -J. , Eds. Scanning Tunneling Microscopy III;157. Chapter 7 : High-Pressure Scanning Tunneling Microscopypressure high-temperature scanning tunneling microscope and

  7. Two-Color Ultrafast Photoexcited Scanning Tunneling Microscopy

    SciTech Connect (OSTI)

    Camillone, N.; Dolocan, A.; Acharya, D.P.; Zahl, P.; Sutter, P.

    2011-05-26T23:59:59.000Z

    We report on two-color two-photon photoexcitation of a metal surface driven by ultrafast laser pulses and detected with a scanning tunneling microscope (STM) tip as a proximate anode. Results are presented for two cases: (i) where the tip is retracted from the surface far enough to prohibit tunneling, and (ii) where the tip is within tunneling range of the surface. A delay-modulation technique is implemented to isolate the two-color photoemission from concurrent one-color two-photon photoemission and provide subpicosecond time-resolved detection. When applied with the tip in tunneling range, this approach effectively isolates the two-photon photoexcited current signal from the conventional tunneling current and enables subpicosecond time-resolved detection of the photoexcited surface electrons. The advantage of the two-color approach is highlighted by comparison with the one-color case where optical interference causes thermal modulation of the STM tip length, resulting in tunneling current modulations that are orders of magnitude larger than the current due to photoexcitation of surface electrons. By completely eliminating this interference, and thereby avoiding thermal modulation of the STM tip length, the two-color approach represents an important step toward the ultimate goal of simultaneous subnanometer and subpicosecond measurements of surface electron dynamics by ultrafast-laser-excited STM.

  8. Neuroreceptor Activation by Vibration-Assisted Tunneling

    E-Print Network [OSTI]

    Ross D. Hoehn; David Nichols; Hartmut Neven; Sabre Kais

    2015-03-24T23:59:59.000Z

    G protein-coupled receptors (GPCRs) constitute a large family of receptor proteins that sense molecular signals on the exterior of a cell and activate signal transduction pathways within the cell. Modeling how an agonist activates such a receptor is fundamental for an understanding of a wide variety of physiological processes and it is of tremendous value for pharmacology and drug design. Inelastic electron tunneling spectroscopy (IETS) has been proposed as a model for the mechanism by which olfactory GPCRs are activated by a bound agonist. We apply this hypothesis to GPCRs within the mammalian nervous system using quantum chemical modeling. We found that non-endogenous agonists of the serotonin receptor share a particular IET spectral aspect both amongst each other and with the serotonin molecule: a peak whose intensity scales with the known agonist potencies. We propose an experiential validation of this model by utilizing lysergic acid dimethylamide (DAM-57), an ergot derivative, and its deuterated isotopologues; we also provide theoretical predictions for comparison to experiment. If validated our theory may provide new avenues for guided drug design and elevate methods of in silico potency/activity prediction.

  9. 2-dimensional hyperbolic medium for electrons and photons based on the array of tunnel-coupled graphene nanoribbons

    E-Print Network [OSTI]

    Iorsh, Ivan

    2015-01-01T23:59:59.000Z

    We study the electronic band structure and optical conductivity of an array of tunnel-coupled array of graphene nanoribbons. We show that due to the coupling of electronic edge states for the zigzag nanoribbon structure, the Fermi surface can become a hyperbola similarly to the case of the layered metal-dielectric structures, where the hyperbolic isofrequency contours originate from the coupling of localized surface plasmon polaritons. Moreover, we show that for both types of the ribbon edge, the optical response of the structure can be characterized by a uniaxial conductivity tensor, having principal components of the different signs. Therefore, the tunnel-coupled nanoribbon array can be regarded as a tunable hyperbolic metasurface.

  10. Tunneling study of epitaxial YBa sub 2 Cu sub 3 O sub x superconducting films

    SciTech Connect (OSTI)

    Boguslavsky, Y.M.; Rudenko, E.M.; Mukhortov, V.M. (Inst. of Metal Physics, Ukrainian Academy of Sciences, 36 Vernadsky str. 252142, Kiev-142 (SU))

    1991-03-01T23:59:59.000Z

    This paper presents planar and edge-type tunnel junctions YBa{sub 2}Cu{sub 3}O{sub x}-metal (Pb,Pt,In) based on epitaxial Y-Ba-Cu-O films. Features of conductance characteristics of these junctions, mainly conductance zero bias anomalies, have been considered. We have observed the difference between the R{sub d}(V) dependences for two types of the contacts at low bias voltages V {approx lt}5 mV. This difference probably linked with an anisotropy of the states density N ({epsilon}) in near-contact region of YBa{sub 2}Cu{sub 3}O{sub x}. Existence of the correlation in the temperature dependences of the states density of YBa{sub 2}Cu{sub 3}O{sub x} along the Cu-O planes and perpendicularly to them have been observed.

  11. Ventilation and Suppression Systems in Road Tunnels: Some Issues regarding their Appropriate Use in a Fire Emergency 

    E-Print Network [OSTI]

    Carvel, Ricky O; Rein, Guillermo; Torero, Jose L

    Two important tunnel safety technologies are addressed. The majority of long road tunnels have ventilation systems. In the event of a fire in a tunnel, such systems will influence fire development in a number of different ...

  12. Baker-Barry Tunnel Lighting: Evaluation of a Potential GATEWAY Demonstrations Project

    SciTech Connect (OSTI)

    Tuenge, Jason R.

    2011-06-28T23:59:59.000Z

    The U.S. Department of Energy is evaluating the Baker-Barry Tunnel as a potential GATEWAY Demonstrations project for deployment of solid-state lighting (SSL) technology. The National Park Service views this project as a possible proving ground and template for implementation of light-emitting diode (LED) luminaires in other tunnels, thereby expanding the estimated 40% energy savings from 132 MWh/yr to a much larger figure nationally. Most of the energy savings in this application is attributable to the instant-restrike capability of LED products and to their high tolerance for frequent on/off switching, used here to separately control either end of the tunnel during daytime hours. Some LED luminaires rival or outperform their high-intensity discharge (HID) counterparts in terms of efficacy, but options are limited, and smaller lumen packages preclude true one-for-one equivalence. However, LED products continue to improve in efficacy and affordability at a rate unmatched by other light source technologies; the estimated simple payback period of eight years (excluding installation costs and maintenance savings) can be expected to improve with time. The proposed revisions to the existing high-pressure sodium (HPS) lighting system would require slightly increased controls complexity and significantly increased luminaire types and quantities. In exchange, substantial annual savings (from reduced maintenance and energy use) would be complemented by improved quantity and quality of illumination. Although advanced lighting controls could offer additional savings, it is unclear whether such a system would prove cost-effective; this topic may be explored in future work.

  13. H-CANYON AIR EXHAUST TUNNEL INSPECTION VEHICLE DEVELOPMENT

    SciTech Connect (OSTI)

    Minichan, R.; Fogle, R.; Marzolf, A.

    2011-05-24T23:59:59.000Z

    The H-Canyon at Savannah River Site is a large concrete structure designed for chemical separation processes of radioactive material. The facility requires a large ventilation system to maintain negative pressure in process areas for radioactive contamination control and personnel protection. The ventilation exhaust is directed through a concrete tunnel under the facility which is approximately five feet wide and 8 feet tall that leads to a sand filter and stack. Acidic vapors in the exhaust have had a degrading effect on the surface of the concrete tunnels. Some areas have been inspected; however, the condition of other areas is unknown. Experience from historical inspections with remote controlled vehicles will be discussed along with the current challenge of inspecting levels below available access points. The area of interest in the exhaust tunnel must be accessed through a 14 X 14 inch concrete plug in the floor of the hot gang valve corridor. The purpose for the inspection is to determine the condition of the inside of the air tunnel and establish if there are any structural concerns. Various landmarks, pipe hangers and exposed rebar are used as reference points for the structural engineers when evaluating the current integrity of the air tunnel.

  14. Calculation and design of tunnel ventilation systems using a two-scale modelling approach 

    E-Print Network [OSTI]

    Colella, Francesco; Rein, Guillermo; Borchiellini, Romano; Carvel, Ricky O; Torero, Jose L; Verda, Vittorio

    This paper develops a novel modelling approach for ventilation flow in tunnels at ambient conditions (i.e. cold flow). The complexity of full CFD models of low in tunnels or the inaccuracies of simplistic assumptions are avoided by efficiently...

  15. Analysis of the ventilation systems in the Dartford tunnels using a multiscale modelling approach 

    E-Print Network [OSTI]

    Colella, Francesco; Rein, Guillermo; Carvel, Ricky O; Reszka, Pedro; Torero, Jose L

    2010-01-01T23:59:59.000Z

    The capabilities of the ventilation systems in the two road tunnels at Dartford (London, UK) are analysed using a multi-scale modelling approach. Both tunnels have complex semi-transverse ventilation systems with jet fans to control longitudinal...

  16. EFFECT OF PREPARATION PARAMETERS ON LIGHT SENSITIVITY IN SUPERCONDUCTIVE TUNNEL JUNCTIONS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    , Italy Résumé. 2014 Des jonctions « tunnel » supraconductrices utilisant du sulfure de cadmium et du al. [17] have considered semiconductor barriers for low capacitance tunnel junctions. Light can be depo- sited in ultra high vacuum systems without fear of contamination. Work

  17. The contribution of asphalt road surfaces to fire risk in tunnel fires: Preliminary findings 

    E-Print Network [OSTI]

    Carvel, Ricky O; Torero, Jose L

    2006-04-19T23:59:59.000Z

    Most fire experiments carried out in tunnels to date have focussed on the burning behaviour and smoke production of liquid pool fires and vehicle fires. Other combustible surfaces, commonly found in tunnels, have not ...

  18. Development of the resource model for the Decision Aids for Tunneling (DAT)

    E-Print Network [OSTI]

    Min, Sangyoon, 1973-

    2008-01-01T23:59:59.000Z

    The Decision Aids for Tunneling (DAT) are a computer based method with which distributions of tunnel construction time and cost as well as required and produced resources can be estimated considering uncertainties in ...

  19. Internal Image Potential in Semiconductors - Effect on Scanning-Tunneling-Microscopy

    E-Print Network [OSTI]

    HUANG, ZH; WEIMER, M.; Allen, Roland E.

    1993-01-01T23:59:59.000Z

    The tunneling of electrons from a semiconductor surface to a metal tip, across a vacuum gap, is influenced by two image interactions: an attractive image potential in the vacuum region, which lowers the apparent tunneling barrier, and a repulsive...

  20. Photon induced tunneling of electron through a graphene electrostatic barrier

    SciTech Connect (OSTI)

    Biswas, R. [Department of Physics, P.K. College, Contai, Purba Medinipur, West Bengal 721401 (India)] [Department of Physics, P.K. College, Contai, Purba Medinipur, West Bengal 721401 (India); Sinha, C. [Department of Theoretical Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)] [Department of Theoretical Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

    2013-11-14T23:59:59.000Z

    The influence of an external intense laser field on the tunneling transport (ballistic) of the Dirac fermions through a monolayer graphene electrostatic barrier is studied in the framework of the Floquet approach for a continuous wave, linearly polarized, monochromatic laser. The Klein tunneling is shown to be suppressed by the irradiation of a strong laser field, arising due to breaking of chiral symmetry. The symmetric nature of the field free angular transmission spectrum around the normal to the well-barrier interface is destroyed due to the additional coupling between the pseudo-spin and the time dependent vector potential. The energy distribution of the tunneling spectrum displays Fano resonance which is absent for a laser assisted conventional electrostatic barrier but similar to the case of quantum well structures, providing an optical tool to identify field free quasi bound states inside the graphene nanostructures.

  1. Axial SiGe Heteronanowire Tunneling Field-Effect Transistors

    SciTech Connect (OSTI)

    Le, Son T.; Jannaty, P.; Luo, Xu; Zaslavsky, A.; Perea, Daniel E.; Dayeh, Shadi A.; Picraux, Samuel T.

    2012-10-31T23:59:59.000Z

    We present silicon-compatible tri-gated p-Ge/i-Si/n-Si axial heteronanowire tunneling field-effect transistors (TFETs), where on-state tunneling occurs in the Ge drain section, while off-state leakage is dominated by the Si junction in the source. Our TFETs have high ION ~ 2 µA/µm, fully suppressed ambipolarity, and a sub-threshold slope SS ~ 140 mV/decade over 4 decades of current with lowest SS ~ 50 mV/decade. Device operation in the tunneling mode is confirmed by three-dimensional TCAD simulation. Interestingly, in addition to the TFET mode, our devices work as standard nanowire FETs with good ION/IOFF ratio when the source-drain junction is forward-biased. The improved transport in both biasing modes confirms the benefits of utilizing bandgap engineered axial nanowires for enhancing device performance.

  2. Decoherence on Quantum Tunneling in the Multi-Dimensional Wave Function Approach

    E-Print Network [OSTI]

    Takahiro Tanaka

    1994-10-07T23:59:59.000Z

    We consider fundamental problems on the understanding of the tunneling phenomena in the context of the multi-dimensional wave function. In this paper, we reconsider the quantum state after tunneling and extend our previous formalism to the case when the quantum state before tunneling is in a squeezed state. Through considering this problem, we reveal that the quantum decoherence plays a crucial role to allow us of the concise description of the quantum state after tunneling.

  3. Programming Wireless Sensor Networks with Logical Neighborhoods: A Road Tunnel Use Case

    E-Print Network [OSTI]

    Picco, Gian Pietro

    on sensed data, the system operates a variety of devices, such as ventilation fans inside the tunnel

  4. Tunneling properties of nonplanar molecules in a gas medium

    SciTech Connect (OSTI)

    Bahrami, Mohammad [Department of Chemistry, Sharif University of Technology, P.O. Box 11365-9516, Tehran (Iran, Islamic Republic of); The Abdus Salam ICTP, Strada Costiera 11, I-34151 Trieste (Italy); Bassi, Angelo [Department of Physics, University of Trieste, Strada Costiera 11, I-34151 Trieste (Italy); Istituto Nazionale di Fisica Nucleare, Trieste Section, Via Valerio 2, I-34127 Trieste (Italy)

    2011-12-15T23:59:59.000Z

    We propose a simple, general, and accurate formula for analyzing the tunneling between classical configurations of a nonplanar molecule in a gas medium, as a function of the thermodynamic parameters of the gas. We apply it to two interesting cases: (i) the shift to zero frequency of the inversion line of ammonia, upon an increase in the pressure of the gas; and (ii) the destruction of the coherent tunneling of D{sub 2}S{sub 2} molecules in a He gas. In both cases, we compare our analysis with previous theoretical and experimental results.

  5. Quality factors and dynamical tunneling in annular microcavities

    E-Print Network [OSTI]

    Arnd Bäcker; Roland Ketzmerick; Steffen Löck; Jan Wiersig; Martina Hentschel

    2009-06-02T23:59:59.000Z

    The key characteristic of an optical mode in a microcavity is its quality factor describing the optical losses. The numerical computation of this quantity can be very demanding for present-day devices. Here we show for a certain class of whispering-gallery cavities that the quality factor is related to dynamical tunneling, a phenomenon studied in the field of quantum chaos. We extend a recently developed approach for determining dynamical tunneling rates to open cavities. This allows us to derive an analytical formula for the quality factor which is in very good agreement with full solutions of Maxwell's equations.

  6. Horizons and Tunneling in the Euclidean False Vacuum

    E-Print Network [OSTI]

    Kate Marvel; Neil Turok

    2007-12-17T23:59:59.000Z

    In the thin-wall approximation, the decay of a gravitating false vacuum to a lower-energy state is affected by the cosmological horizon structure in both spaces. The nucleation radius of a bubble of true vacuum depends on the surface tension of its boundary and equals the false vacuum cosmological horizon at a critical tension. We argue that there is no tunneling instanton solution beyond the critical tension and argue that there is therefore a bound on allowed membrane tension in theories which rely on semiclassical tunneling to relax the cosmological constant.

  7. Are the tunnel ventilation systems adapted for the different risk situations?

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Are the tunnel ventilation systems adapted for the different risk situations? B. TRUCHOT * INERIS Tunnels, France ABSTRACT The ventilation design criteria for both road and rail tunnel is based of such an approach is that it considers only the impact on the safety ventilation of the smoke propagation

  8. Vibration-Induced Kondo Tunneling through Metal-Organic Complexes with Even Electron Occupation Number

    E-Print Network [OSTI]

    - neling Hamiltonian H Hmol Hres Htun: (1) Here Hmol includes the 3d electron levels in a ligand field of the cage electrons, the molecular orbitals of these ligands, as well as interactions within the 3d shell with tunneling electrons (vibration assisted tunneling) [8­13] and modulation of the tunnel barriers (shuttling

  9. Developing a Practical Wind Tunnel Test Engineering Course for Undergraduate Aerospace Engineering Students

    E-Print Network [OSTI]

    Recla, Benjamin Jeremiah

    2013-04-19T23:59:59.000Z

    This thesis describes the development and assessment of an undergraduate wind tunnel test engineering course utilizing the 7ft by 10ft Oran W. Nicks Low Speed Wind Tunnel (LSWT). Only 5 other universities in the United States have a wind tunnel...

  10. Molecularly Resolved Images of Peptide-Functionalized Gold Surfaces by Scanning Tunneling Microscopy

    E-Print Network [OSTI]

    Webb, Lauren J.

    Molecularly Resolved Images of Peptide-Functionalized Gold Surfaces by Scanning Tunneling propargylglycine unnatural functional groups 20 Å apart and an alkanethiol self-assembled monolayer (SAM) on a gold-terminated surfaces were imaged by scanning tunneling microscopy (STM) using a low tunneling current of 10 p

  11. Observation of Turbulent Intermittency Scaling with Magnetic Helicity in an MHD Plasma Wind Tunnel

    E-Print Network [OSTI]

    Brown, Michael R.

    . An unstable spheromak injected into the MHD wind tunnel of the Swarthmore Spheromak Experiment displays-tunnel configuration of the Swarthmore Spheromak Experiment (SSX) [16,17] explores this possible relationship between indices. The scan is conducted on the wind-tunnel configuration of the Swarthmore Spheromak Experiment

  12. REVIEW OF SCIENTIFIC INSTRUMENTS 82, 033510 (2011) Calibrated cylindrical Mach probe in a plasma wind tunnel

    E-Print Network [OSTI]

    Brown, Michael R.

    2011-01-01T23:59:59.000Z

    wind tunnel X. Zhang,1,a) D. Dandurand,1 T. Gray,1 M. R. Brown,1 and V. S. Lukin2 1 Department probe is described along with an independent calibration procedure in a magnetized plasma wind tunnel calibration method based on magnetic time-of-flight in a magnetized wind tunnel is pre- sented and a particle

  13. Ris-R-999(EN) Wind Tunnel Test of the RIS-1

    E-Print Network [OSTI]

    Risø-R-999(EN) Wind Tunnel Test of the RISØ-1 Airfoil Peter Fuglsang, Ioannis Antoniou, Christian Bak, Helge Aa. Madsen Risø National Laboratory, Roskilde May 1998 #12;Abstract Wind tunnel tests with approximately 2d flow were carried out for the RISØ-1 airfoil in the VELUX open jet wind tunnel. The airfoil

  14. Tunneling processes in asymmetric double barrier magnetic tunnel junctions with a thin top MgO layer

    SciTech Connect (OSTI)

    Li, D. L.; Feng, J. F. [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); CRANN and School of Physics, Trinity College, Dublin 2 (Ireland); Yu, G. Q.; Guo, P.; Wei, H. X.; Han, X. F., E-mail: xfhan@aphy.iphy.ac.cn [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Chen, J. Y.; Coey, J. M. D. [CRANN and School of Physics, Trinity College, Dublin 2 (Ireland)

    2013-12-07T23:59:59.000Z

    Dynamic conductance dI/dV and inelastic electron tunneling spectroscopy (IETS) d{sup 2}I/dV{sup 2} have been measured at different temperatures for double barrier magnetic tunnel junctions with a thin top MgO layer. The resistance in the antiparallel state exhibits a normal tunnel-like behavior, while the resistance in the parallel state shows metallic-like transport, indicating the presence of pinholes in the thin top MgO layer. Three IETS peaks are the zero-bias anomaly, interface magnons, and barrier phonons in both the parallel and antiparallel states. The zero-bias anomaly is the strongest peak in the parallel state and its intensity decreases with temperature. The magnon has the largest intensity in the antiparallel state and its intensity also decreases with temperature. The origins of the dips and peaks in the dI/dV-V curve are also discussed.

  15. Very low 1/f barrier noise in sputtered MgO magnetic tunnel junctions with high tunneling magnetoresistance

    SciTech Connect (OSTI)

    Feng, J. F.; Chen, J. Y.; Kurt, H.; Coey, J. M. D. [CRANN and School of Physics, Trinity College, Dublin 2 (Ireland)

    2012-12-15T23:59:59.000Z

    Low frequency 1/f barrier noise has been investigated in sputtered MgO magnetic tunnel junctions (MTJs) with a tunneling magnetoresistance ratio of up to 330% at room temperature. The lowest normalized noise parameter {alpha} of the tunnel barrier reaches 2.5 Multiplication-Sign 10{sup -12}-2.1 Multiplication-Sign 10{sup -11} {mu}m{sup 2}, which is comparable to that found in MTJs with the MgO barrier grown by MBE or electron-beam evaporation. This normalized barrier noise is almost bias independent in the voltage range of up to {+-}1.2 V. The low noise level and high voltage stability may reflect the high quality of the sputtered MgO with a uniform distribution of defects in the MgO layer.

  16. Analysis of the energy distribution of interface traps related to tunnel oxide degradation using charge pumping techniques for 3D NAND flash applications

    SciTech Connect (OSTI)

    An, Ho-Myoung; Kim, Hee-Dong; Kim, Tae Geun, E-mail: tgkim1@korea.ac.kr

    2013-12-15T23:59:59.000Z

    Graphical abstract: The degradation tendency extracted by CP technique was almost the same in both the bulk-type and TFT-type cells. - Highlights: • D{sub it} is directly investigated from bulk-type and TFT-type CTF memory. • Charge pumping technique was employed to analyze the D{sub it} information. • To apply the CP technique to monitor the reliability of the 3D NAND flash. - Abstract: The energy distribution and density of interface traps (D{sub it}) are directly investigated from bulk-type and thin-film transistor (TFT)-type charge trap flash memory cells with tunnel oxide degradation, under program/erase (P/E) cycling using a charge pumping (CP) technique, in view of application in a 3-demension stackable NAND flash memory cell. After P/E cycling in bulk-type devices, the interface trap density gradually increased from 1.55 × 10{sup 12} cm{sup ?2} eV{sup ?1} to 3.66 × 10{sup 13} cm{sup ?2} eV{sup ?1} due to tunnel oxide damage, which was consistent with the subthreshold swing and transconductance degradation after P/E cycling. Its distribution moved toward shallow energy levels with increasing cycling numbers, which coincided with the decay rate degradation with short-term retention time. The tendency extracted with the CP technique for D{sub it} of the TFT-type cells was similar to those of bulk-type cells.

  17. Tunnel junction multiple wavelength light-emitting diodes

    DOE Patents [OSTI]

    Olson, Jerry M. (Lakewood, CO); Kurtz, Sarah R. (Golden, CO)

    1992-01-01T23:59:59.000Z

    A multiple wavelength LED having a monolithic cascade cell structure comprising at least two p-n junctions, wherein each of said at least two p-n junctions have substantially different band gaps, and electrical connector means by which said at least two p-n junctions may be collectively energized; and wherein said diode comprises a tunnel junction or interconnect.

  18. Topeka’s “Green Light Tunnel” Saves Fuel and Time

    Broader source: Energy.gov [DOE]

    Topeka, Kansas is saving their motorists time and gasoline through the use of a real-time, adaptive "green light tunnel". A traffic signal system that synchronizes traffic lights in order to create a series of green lights that result in fewer stops and less travel time.

  19. Tunnel junction multiple wavelength light-emitting diodes

    DOE Patents [OSTI]

    Olson, J.M.; Kurtz, S.R.

    1992-11-24T23:59:59.000Z

    A multiple wavelength LED having a monolithic cascade cell structure comprising at least two p-n junctions, wherein each of said at least two p-n junctions have substantially different band gaps, and electrical connector means by which said at least two p-n junctions may be collectively energized; and wherein said diode comprises a tunnel junction or interconnect. 5 figs.

  20. Surface Science Letters Scanning tunneling microscopy study of the anatase

    E-Print Network [OSTI]

    Diebold, Ulrike

    ; Surface structure, morphology, roughness, and topography; Low index single crystal surfaces The structureSurface Science Letters Scanning tunneling microscopy study of the anatase (1 0 0) surface NancyO2 anatase (1 0 0) surface. Natural single crystals of anatase were employed; and after several

  1. SCANNING TUNNELING MICROSCOPE ASSEMBLY INSTRUCTIONS FOR NANOSCOPE II

    E-Print Network [OSTI]

    SCANNING TUNNELING MICROSCOPE ASSEMBLY INSTRUCTIONS FOR NANOSCOPE II 1) Set monitor #1 on top side of the able. 3) Set the keyboard on top and front of the computer. 4) Set the scanning head on gel into the scanning head. 12) Suspend bungee cords, as necessary, from a secure point in the ceiling. 13) Fasten onto

  2. INFLATABLE PLUG FOR THREAT MITIGATION IN TRANSPORTATION TUNNELS

    E-Print Network [OSTI]

    Barbero, Ever J.

    INFLATABLE PLUG FOR THREAT MITIGATION IN TRANSPORTATION TUNNELS Xavier Martinez1 , Julio Davalos2 and government entities. Fires, noxious fumes, deadly gasses, and flooding threats have occurred in major are of difficult and limited accessibility, but also because most of the potential threats, such as fires, flooding

  3. Tunnel MOS Heterostructure Field Effect Transistor for RF Switching Applications

    E-Print Network [OSTI]

    Rezanezhad Gatabi, Iman

    2013-06-06T23:59:59.000Z

    6 dry etching on the trap density and trap state energy of AlGaN surface are investigated using the GP/w- w method. Various tunneling mechanisms at different biases are then characterized in samples and compared with each other. To improve...

  4. Extraction of the tunnel magnetocapacitance with two-terminal measurements

    E-Print Network [OSTI]

    Lin, Minn-Tsong

    Extraction of the tunnel magnetocapacitance with two-terminal measurements Yin-Ming Chang,1 Kai in the four-terminal measurement with high frequency operation, two-terminal approach was developed circuit analy- sis with four-terminal complex impedance measurements. Aside from their conclusion

  5. Losses in superconducting Niobium Films caused by Interface Tunnel Exchange

    E-Print Network [OSTI]

    Junginger, Tobias; Welsch, Carsten

    2012-01-01T23:59:59.000Z

    Identifying the loss mechanisms of niobium film cavities enables an accurate determination of applications for future accelerator projects and points to research topics required to mitigate their limitations. Measurements on samples show that the electric field is a dominant loss mechanism for niobium films, acting through interface tunneling between localized states in surface oxides and delocalized states in the superconducting niobium.

  6. area lhc tunnel: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Keith 2006-01-01 9 A High Luminosity e+e- Collider in the LHC tunnel to study the Higgs Boson HEP - Experiment (arXiv) Summary: We consider the possibility of a 120x120 GeV e+e-...

  7. Tunneling control using classical non-linear oscillator

    SciTech Connect (OSTI)

    Kar, Susmita [Department of Physical Chemistry, Indian Association for the Cultivation of Science, Kolkata -700032 (India); Bhattacharyya, S. P., E-mail: pcspb@chem.iitb.ac.in [Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai- 400076 (India)

    2014-04-24T23:59:59.000Z

    A quantum particle is placed in symmetric double well potential which is coupled to a classical non-linear oscillator via a coupling function. With different spatial symmetry of the coupling and under various controlling fashions, the tunneling of the quantum particle can be enhanced or suppressed, or totally destroyed.

  8. Exercice session Cargse, October 2008 Klein tunneling in graphene

    E-Print Network [OSTI]

    Paris-Sud 11, Université de

    Exercice session Cargèse, October 2008 Klein tunneling in graphene Pierre Allain and Jean-Noël Fuchs 1 Introduction : plane wave The goal is to compute the probability transmission T of a graphene 1 = n2 sin 2 for an electron in graphene and show that the optical index n is proportional

  9. Particle production related to the tunneling in false vacuum decay

    E-Print Network [OSTI]

    Michael Maziashvili

    2003-02-15T23:59:59.000Z

    Motivated by the work of Mersini, the particle production related to the tunneling in false vacuum decay is carefully investigated in the thin-wall approximation. It is shown that in this case the particle production is exponentially suppressed even when the momentum is comparable to the curvature scale of the bubble. The number of created particles is ultraviolet finite.

  10. Macroscopic quantum tunneling and the 'cosmic' Josephson effect

    SciTech Connect (OSTI)

    Barone, A. [Dipartimento di Scienze Fisiche, Universita di Napoli 'Federico II', CNR-SPIN, Piazzale Tecchio 21, 80125 Napoli (Italy); Gasperini, M. [Dipartimento di Fisica, Universita di Bari, Via G. Amendola 173, 70126 Bari (Italy); INFN, Sezione di Bari, Bari (Italy); Rotoli, G. [Dipartimento di Ingegneria dell'Informazione, Seconda Universita di Napoli (SUN), Via Roma 29, 81031 Aversa (CE) (Italy)

    2010-10-15T23:59:59.000Z

    We discuss the possible influence of a cosmic magnetic field on the macroscopic quantum tunneling process associated, in a cosmological context, to the decay of the 'false vacuum'. We find a close analogy with the effects of an external magnetic field applied to a Josephson junction in the context of low-temperature/high-temperature superconducting devices.

  11. Wind and saltation driven particle resuspension in a wind tunnel

    SciTech Connect (OSTI)

    Fairchild, C.I.; Tillery, M.I.; Wheat, L.D.; Redmond, D.J.

    1985-01-01T23:59:59.000Z

    To determine parameters of primary importance in wind and saltation driven resuspension of fine particles from surfaces, wind tunnel experiments were conducted to study the resuspension of small polydisperse particles (diameter <10 ..mu..m) by monodisperse saltation particles (diameter >80 ..mu..m). The experiments were designed to simulate the atmospheric boundary layer resuspension of fine particles. 3 refs., 1 tab.

  12. Simulation of localized barrier defects in resonant tunneling diodes

    E-Print Network [OSTI]

    Stoneberg, Jason Neal

    1995-01-01T23:59:59.000Z

    Much research has been devoted to understanding the resonant tunneling diode in the last two decades, but some aspects of current conduction in this device are still not well understood. At Texas A&M University, Weichold, et al., have proposed...

  13. Tunnel MOS Heterostructure Field Effect Transistor for RF Switching Applications 

    E-Print Network [OSTI]

    Rezanezhad Gatabi, Iman

    2013-06-06T23:59:59.000Z

    structure called “Tunnel MOS Heterostructure FET (TMOSHFET)” is introduced which has lower ON-state resistance and faster switching speed compared to conventional AlGaN/GaN HEMTs. In the switch ON process, the channel of this device is charged up by electron...

  14. Anisotropic Kantowski-Sachs Universe from Gravitational Tunneling and its Observational Signatures

    E-Print Network [OSTI]

    Julian Adamek; David Campo; Jens C. Niemeyer

    2010-09-07T23:59:59.000Z

    In a landscape of compactifications with different numbers of macroscopic dimensions, it is possible that our universe has nucleated from a vacuum where some of our four large dimensions were compact while other, now compact, directions were macroscopic. From our perspective, this shapeshifting can be perceived as an anisotropic background spacetime. As an example, we present a model where our universe emerged from a tunneling event which involves the decompactification of two dimensions compactified on the two-sphere. In this case, our universe is of the Kantowski-Sachs type and therefore homogeneous and anisotropic. We study the deviations from statistical isotropy of the Cosmic Microwave Background induced by the anisotropic curvature, with particular attention to the anomalies. The model predicts a quadrupolar power asymmetry with the same sign and acoustic oscillations as found by WMAP. The amplitude of the effect is however too small given the current estimated bound on anisotropic curvature derived from the quadrupole.

  15. Anisotropic Kantowski-Sachs Universe from Gravitational Tunneling and its Observational Signatures

    E-Print Network [OSTI]

    Adamek, Julian; Niemeyer, Jens C

    2010-01-01T23:59:59.000Z

    In a landscape of compactifications with different numbers of macroscopic dimensions, it is possible that our universe has nucleated from a vacuum where some of our four large dimensions were compact while other, now compact, directions were macroscopic. From our perspective, this shapeshifting can be perceived as an anisotropic background spacetime. As an example, we present a model where our universe emerged from a tunneling event which involves the decompactification of two dimensions compactified on the two-sphere. In this case, our universe is of the Kantowski-Sachs (KS) type and therefore homogeneous and anisotropic. We study the deviations from statistical isotropy of the Cosmic Microwave Background (CMB) induced by the RxS2-topology of the KS universe and present a preliminary discussion of their observability if inflation was sufficiently short.

  16. Polarization-engineered GaN/InGaN/GaN tunnel diodes

    E-Print Network [OSTI]

    Sriram Krishnamoorthy; Digbijoy N. Nath; Fatih Akyol; Pil Sung Park; Michele Esposto; Siddharth Rajan

    2010-08-24T23:59:59.000Z

    We report on the design and demonstration of polarization-engineered GaN/InGaN/GaN tunnel junction diodes with high current density and low tunneling turn-on voltage. Wentzel-Kramers-Brillouin (WKB) calculations were used to model and design tunnel junctions with narrow bandgap InGaN-based barrier layers. N-polar p-GaN/In0.33Ga0.67N/n-GaN heterostructure tunnel diodes were grown using molecular beam epitaxy. Efficient zero bias tunneling turn-on with a high current density of 118 A/cm2 at a reverse bias of 1V, reaching a maximum current density up to 9.2 kA/cm2 were obtained. These results represent the highest current density reported in III-nitride tunnel junctions, and demonstrate the potential of III-nitride tunnel devices for a broad range of optoelectronic and electronic applications.

  17. Award Types

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProductsAlternativeOperationalAugust AugustInstruments on theAward Types Types of

  18. SciTech Connect: Passivated Tunneling Contacts to N-Type Wafer...

    Office of Scientific and Technical Information (OSTI)

    Golden, CO. Sponsoring Org: USDOE Office of Energy Efficiency and Renewable Energy Solar Energy Technologies Office Country of Publication: United States Language: English...

  19. Merguerian, Charles; and Ozdemir, Levent, 2003, Rock Mass Properties and Hard Rock TBM Penetration Rate Investigations, Queens Tunnel Complex, NYC Water Tunnel #3, Stage 2: p.

    E-Print Network [OSTI]

    Merguerian, Charles

    Merguerian, Charles; and Ozdemir, Levent, 2003, Rock Mass Properties and Hard Rock TBM Penetration Properties and Hard Rock TBM Penetration Rate Investigations, Queens Tunnel Complex, NYC Water Tunnel #3 quantification that the rock mass exhibited an unusually high degree of toughness and rock directional properties

  20. Tunnel and Subsurface Void Detection and Range to Target Measurement

    SciTech Connect (OSTI)

    Phillip B. West

    2009-06-01T23:59:59.000Z

    Engineers and technicians at the Idaho National Laboratory invented, designed, built and tested a device capable of detecting and measuring the distance to, an underground void, or tunnel. Preliminary tests demonstrated positive detection of, and range to, a void thru as much as 30 meters of top-soil earth. Device uses acoustic driving point impedance principles pioneered by the Laboratory for well-bore physical properties logging. Data receipts recorded by the device indicates constructive-destructive interference patterns characteristic of acoustic wave reflection from a downward step-change in impedance mismatch. Prototype tests demonstrated that interference patterns in receipt waves could depict the patterns indicative of specific distances. A tool with this capability can quickly (in seconds) indicate the presence and depth/distance of a void or tunnel. Using such a device, border security and military personnel can identify threats of intrusion or weapons caches in most all soil conditions including moist and rocky.

  1. Analysis of different tunneling mechanisms of In{sub x}Ga{sub 1?x}As/AlGaAs tunnel junction light-emitting transistors

    SciTech Connect (OSTI)

    Wu, Cheng-Han [Graduate Institute of Electronics Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan (China); Wu, Chao-Hsin, E-mail: chaohsinwu@ntu.edu.tw [Graduate Institute of Electronics Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan (China); Graduate Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan (China)

    2014-10-27T23:59:59.000Z

    The electrical and optical characteristics of tunnel junction light-emitting transistors (TJLETs) with different indium mole fractions (x?=?5% and 2.5%) of the In{sub x}Ga{sub 1?x}As base-collector tunnel junctions have been investigated. Two electron tunneling mechanisms (photon-assisted or direct tunneling) provide additional currents to electrical output and resupply holes back to the base region, resulting in the upward slope of I-V curves and enhanced optical output under forward-active operation. The larger direct tunneling probability and stronger Franz-Keldysh absorption for 5% TJLET lead to higher collector current slope and less optical intensity enhancement when base-collector junction is under reverse-biased.

  2. Hanford facility dangerous waste permit application, PUREX storage tunnels

    SciTech Connect (OSTI)

    Haas, C. R.

    1997-09-08T23:59:59.000Z

    The Hanford Facility Dangerous Waste Permit Application is considered to be a single application organized into a General Information Portion (document number DOE/RL-91-28) and a Unit-Specific Portion. The scope of the Unit-Specific Portion is limited to Part B permit application documentation submitted for individual, `operating` treatment, storage, and/or disposal units, such as the PUREX Storage Tunnels (this document, DOE/RL-90-24).

  3. Nanopillar Spin Filter Tunnel Junctions with Manganite Barriers

    E-Print Network [OSTI]

    Prasad, Bhagwati; Egilmez, Mehmet; Schoofs, Frank; Fix, Thomas; Vickers, Mary E; Zhang, Wenrui; Jian, Jie; Wang, Haiyan; Blamire, Mark G

    2014-04-17T23:59:59.000Z

    of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK ‡ Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, 77843-3128, USA KEYWORDS: Spin filter, Nano... magnetic memories, reprogrammable logic and quantum computers.1,2 These devices rely on the generation of highly spin-polarized currents. Spin filter tunnel junction (SFTJ) has emerged as a promising alternative for this purpose. A possible way...

  4. A 233 km tunnel for lepton and hadron colliders

    SciTech Connect (OSTI)

    Summers, D. J.; Cremaldi, L. M.; Datta, A.; Duraisamy, M.; Luo, T.; Lyons, G. T. [Dept. of Physics and Astronomy, University of Mississippi-Oxford, University, MS 38677 (United States)

    2012-12-21T23:59:59.000Z

    A decade ago, a cost analysis was conducted to bore a 233 km circumference Very Large Hadron Collider (VLHC) tunnel passing through Fermilab. Here we outline implementations of e{sup +}e{sup -}, pp-bar , and {mu}{sup +}{mu}{sup -} collider rings in this tunnel using recent technological innovations. The 240 and 500 GeV e{sup +}e{sup -} colliders employ Crab Waist Crossings, ultra low emittance damped bunches, short vertical IP focal lengths, superconducting RF, and low coercivity, grain oriented silicon steel/concrete dipoles. Some details are also provided for a high luminosity 240 GeV e{sup +}e{sup -} collider and 1.75 TeV muon accelerator in a Fermilab site filler tunnel. The 40 TeV pp-bar collider uses the high intensity Fermilab p-bar source, exploits high cross sections for pp-bar production of high mass states, and uses 2 Tesla ultra low carbon steel/YBCO superconducting magnets run with liquid neon. The 35 TeV muon ring ramps the 2 Tesla superconducting magnets at 9 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 1.75 to 17.5 TeV in 63 orbits with 71% survival, and mitigates neutrino radiation with phase shifting, roller coaster motion in a FODO lattice.

  5. Subbarrier fusion reactions and many-particle quantum tunneling

    E-Print Network [OSTI]

    K. Hagino; N. Takigawa

    2012-10-17T23:59:59.000Z

    Low energy heavy-ion fusion reactions are governed by quantum tunneling through the Coulomb barrier formed by a strong cancellation of the repulsive Coulomb force with the attractive nuclear interaction between the colliding nuclei. Extensive experimental as well as theoretical studies have revealed that fusion reactions are strongly influenced by couplings of the relative motion of the colliding nuclei to several nuclear intrinsic motions. Heavy-ion subbarrier fusion reactions thus provide a good opportunity to address a general problem on quantum tunneling in the presence of couplings, which has been a popular subject in the past decades in many branches of physics and chemistry. Here we review theoretical aspects of heavy-ion subbarrier fusion reactions from the view point of quantum tunneling in systems with many degrees of freedom. Particular emphases are put on the coupled-channels approach to fusion reactions, and the barrier distribution representation for multi-channel penetrability. We also discuss an application of the barrier distribution method to elucidation of the mechanism of dissociative adsorption of H$_2$ melecules in surface science.

  6. Baker-Barry Tunnel Lighting: Evaluation of a Potential GATEWAY Demonstrations Project

    SciTech Connect (OSTI)

    Tuenge, Jason R.

    2011-06-01T23:59:59.000Z

    The U.S. Department of Energy (DOE) is evaluating the Baker-Barry Tunnel as a potential GATEWAY Demonstrations project for deployment of solid-state lighting (SSL) technology. The National Park Service (NPS) views this project as a possible proving ground and template for implementation of light-emitting diode (LED) luminaires in other NPS tunnels, thereby expanding the estimated 40% energy savings from 132 MWh/yr for this tunnel to a much larger figure national

  7. GaAsSb-based heterojunction tunnel diodes for tandem solar cell interconnects

    SciTech Connect (OSTI)

    Zolper, J.C.; Klem, J.F.; Plut, T.A.; Tigges, C.P.

    1995-01-01T23:59:59.000Z

    We report a new approach to tunnel junctions that employs a pseudomorphic GaAsSb layer to obtain a band alignment at a InGaAs or InAlAs p-n junction favorable for forward bias tunneling. Since the majority of the band offset between GaAsSb and InGaAs or InAlAs is in the valence band, when an GaAsSb layer is placed at an InGaAs or InAlAs p-n junction the tunneling distance is reduced and the tunneling current is increased. For all doping levels studied, the presence of the GaAsSb-layer enhanced the forward tunneling characteristics. In fact, in a InGaAs/GaAsSb tunnel diode a peak tunneling current sufficient for a 1000 sun intercell interconnect was achieved with p = 1.5{times}l0{sup 18} cm{sup -3} while a similarly doped all-InGaAs diode was rectifying. This approach affords a new degree of freedom in designing tunnel junctions for tandem solar cell interconnects. Previously only doping levels could be varied to control the tunneling properties. Our approach relaxes the doping requirements by employing a GaAsSb-based heterojunction.

  8. Evaluation of PM10 and Total Suspended Particulate Sampler Performance Through Wind Tunnel Testing

    E-Print Network [OSTI]

    Thelen, Mary Katherine

    2011-10-21T23:59:59.000Z

    .................................................... 86 APPENDIX F SHARP-EDGE ORIFICE METER CALIBRATION PROCEDURE ................................................................................ 89 APPENDIX G TEXAS A&M WIND TUNNEL OPERATION PROCEDURE ... 92 APPENDIX H MALVER MASTERSIZER 2000...

  9. Department of Mechanical and Nuclear Engineering Spring 2011 Wind Tunnel Automation Project

    E-Print Network [OSTI]

    Demirel, Melik C.

    PENNSTATE Department of Mechanical and Nuclear Engineering Spring 2011 Wind Tunnel Automation Project Phase II - Automated Bike Turret Mount Overview SYNERGE LLC is a consulting company working

  10. Vital Alert's C1000 mine and tunnel radios use magnetic induction...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and tunnel radios use magnetic induction, advanced digital communications techniques and ultra-low frequency transmission to wirelessly provide reliable 2-way voice, text, or data...

  11. Comment on "Direct space-time observation of pulse tunneling in an electromagnetic band gap"

    E-Print Network [OSTI]

    G. Nimtz; A. A. Stahlhofen

    2008-01-13T23:59:59.000Z

    The investigation presented by Doiron, Hache, and Winful [Phys. Rev. A 76, 023823 (2007)] is not valid for the tunneling process as claimed in the paper.

  12. Automatic signal processing of front monitor radar for tunneling machines

    SciTech Connect (OSTI)

    Sato, Toru [Kyoto Univ. (Japan). Dept. of Electronics and Communication] [Kyoto Univ. (Japan). Dept. of Electronics and Communication; Takeda, Kenya [NTT Co. Ltd., Chiba (Japan)] [NTT Co. Ltd., Chiba (Japan); Nagamatsu, Takashi [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)] [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan); Wakayama, Toshio [Mitsubishi Electric Corp., Kamakura, Kanagawa (Japan)] [Mitsubishi Electric Corp., Kamakura, Kanagawa (Japan); Kimura, Iwane [Osaka Inst. of Tech., Hirakata, Osaka (Japan)] [Osaka Inst. of Tech., Hirakata, Osaka (Japan); Shinbo, Tetsuya [Komatsu Co. Ltd., Kanagawa (Japan)] [Komatsu Co. Ltd., Kanagawa (Japan)

    1997-03-01T23:59:59.000Z

    It is planned to install a front monitoring impulse radar on the surface of the rotating drill of tunneling machines in order to detect obstacles such as casing pipes of vertical borings. The conventional aperture synthesis technique can no more be applied to such cases because the radar image of a pipe dies not constituent a hyperbola as is the case for linear scanning radars. The authors have developed a special purpose signal processing algorithm with the aid of the discrete model fitting method, which can be used for any pattern of scanning. The details of the algorithm are presented together with the results of numerical simulations and test site experiments.

  13. Observation of diamond turned OFHC copper using Scanning Tunneling Microscopy

    SciTech Connect (OSTI)

    Grigg, D.A.; Russell, P.E.; Dow, T.A.

    1988-12-01T23:59:59.000Z

    Diamond turned OFHC copper samples have been observed within the past few months using the Scanning Tunneling Microscope. Initial results have shown evidence of artifacts which may be used to better understand the diamond turning process. The STM`s high resolution capability and three dimensional data representation allows observation and study of surface features unobtainable with conventional profilometry systems. Also, the STM offers a better quantitative means by which to analyze surface structures than the SEM. This paper discusses findings on several diamond turned OFHC copper samples having different cutting conditions. Each sample has been cross referenced using STM and SEM.

  14. A DONOR COMPLEX WITH TUNNELING HYDROGEN IN PURE GERMANIUM

    SciTech Connect (OSTI)

    Joos, B.; Haller, E.E.; Falicov, L.M.

    1980-02-01T23:59:59.000Z

    A shallow donor complex observed by several authors in ultrapure germanium grown in a hydrogen atmosphere is attributed to an oxygen-hydrogen system. Photoconductivity data under stress are presented. An abrupt transition in the spectra at a well-defined stress (2.1 x 10{sup 8} dyn cm{sup -2}) is found. It is explained by a theory which involves dynamic tunneling of the hydrogen in the vicinity of an oxygen center. The comparison with other complex donors and acceptors supports the model.

  15. Fabrication of a gated gallium arsenide heterostructure resonant tunneling diode

    E-Print Network [OSTI]

    Kinard, William Brian

    1989-01-01T23:59:59.000Z

    , . ' 'CONTACT PAD' PLANAR I ZED POLYAM I DE RECTIFYI CONTACT N DBHS Pig. 2. f'utavvay vieiv of a gated gallium arsenide heterostructure resonant tunneling diode 1018 graded from 10 18 io" 10? (lightly doped) units=cm 8 ?graded from 10 to 18...FABRICATION OF A GATED GALLIL". tl ARSEXIDE HETEROSTRL CTL RF. RESONANT TF'XXELI'XG DIODE A Thesis bt ttrILLIAAI BRIA'. s KI'iARD Subnut ted to the Office of Graduate Studies of Texas AE;M Eniverstty tn partial fulfillment of the requirements...

  16. Air flow through common type window openings

    E-Print Network [OSTI]

    Holleman, Theo Rufus

    1951-01-01T23:59:59.000Z

    surface pressures surrounding it? WIM O TA L E AIR WASHER LOUVERS- EXCELSIOR MAT WATER SPRAY ~-- ? EGG CRATE ~ ? CHEESE -CLOTH / Figure 4 Wind Tunnel (Flan and Section) Courtesy of Texas Engineering Exgerirent Station psgure 4-p Wind Tunnel...

  17. Wind Tunnel and Field Test of Three 2D Sonic Anemometers

    E-Print Network [OSTI]

    Stoffelen, Ad

    Wind Tunnel and Field Test of Three 2D Sonic Anemometers Wiel Wauben R&D Information and Observation Technology, KNMI September 17, 2007 #12;#12;Wind Tunnel and Field Test of Three 2D Sonic.....................................................................................................1 2. Wind sensors

  18. DETECTION OF GEOTHERMAL INTERFERENCE IN THE TUNNEL EXCAVATION USING MAGNETOTELLURICS TECHNIQUE

    E-Print Network [OSTI]

    Harinarayana, T.

    temperature of the hot springs is as high as 900 C at some places. Major civil construction sites such as dams, tunnels etc. need to be carefully planned to avoid the hot spring locations. For example, high temperature-engineers involved in tunnel construction in Himalayas is to know the possible interference of hot water regimes

  19. An ultrahigh vacuum fast-scanning and variable temperature scanning tunneling microscope for large scale imaging

    E-Print Network [OSTI]

    Pohl, Karsten

    An ultrahigh vacuum fast-scanning and variable temperature scanning tunneling microscope for large describe the design and performance of a fast-scanning, variable temperature scanning tunneling microscope of the scanner tube. The total scanning area is about 8 8 m2 . The sample temperature can be adjusted by a few

  20. Integrated micro-scanning tunneling microscope Y. Xu and N. C. MacDonald

    E-Print Network [OSTI]

    MacDonald, Noel C.

    Integrated micro-scanning tunneling microscope Y. Xu and N. C. MacDonald School of Electrical of micro-scanning tunneling microscopes micro-STMs have been fabricated. The integrated micro metal conductor on a silicon chip. © 1995 American Institute of Physics. Scanned-probe instruments have

  1. Instability of a nonequilibrium state of superconducting niobium films during tunneling injection of quasiparticles

    SciTech Connect (OSTI)

    Pan, V.M.; Rudenko, E.M.

    1981-07-20T23:59:59.000Z

    Experiments show that intense tunneling injection of quasiparticles may be accompanied by an instability of a nonequilibriun state in a niobium film. The threshold current for the instability, I/sub i/, has been found as a function of the bath temperature T/sub b/ and of the local temperature near the tunneling contact, T/sub l/.

  2. Influence of dimensionality on deep tunneling rates: A study based on the hydrogen-nickel system

    E-Print Network [OSTI]

    Zeiri, Yehuda

    Influence of dimensionality on deep tunneling rates: A study based on the hydrogen-nickel system hydrogen into a surface site of a nickel crystal is used to investigate deep tunneling phenomena. A method of a hydrogen atom in a nickel fcc crystal is studied. The atom is located in a subsurface interstitial site

  3. Lateral imaging of the superconducting vortex lattice using Doppler-modulated scanning tunneling microscopy

    E-Print Network [OSTI]

    Wei, John Y.T.

    Lateral imaging of the superconducting vortex lattice using Doppler-modulated scanning tunneling on the quasiparticle tunneling spectrum, we have laterally imaged the vortex lattice in superconducting 2H-NbSe2 that circulates along the sample edge. Above the lower critical field, field can penetrate into the superconductor

  4. Oxygen driven reconstruction dynamics of Ni,,977... measured by time-lapse scanning tunneling microscopy

    E-Print Network [OSTI]

    Sibener, Steven

    Oxygen driven reconstruction dynamics of Ni,,977... measured by time-lapse scanning tunneling-lapse scanning tunneling microscopy STM has been used to observe the oxygen induced reconstruction behavior of Ni for the merging of steps in the presence of small amounts of adsorbed oxygen, less than 2% of a monolayer. Point

  5. Assessment of Flow Efficiency Through a Closed Circuit Wind Tunnel with Recommendations for Improvements

    E-Print Network [OSTI]

    Guthery, John

    2013-12-02T23:59:59.000Z

    Wind tunnels are designed for a certain range of test velocities and model sizes. The Oran W. Nicks Low Speed Wind Tunnel (LSWT) at Texas A&M, was designed to reach 200 mph (M=0.26) with its original 1250 hp motor and 7 x 10 ft test section. In 2012...

  6. The development of a wind tunnel facility for the study of V/STOL noise

    E-Print Network [OSTI]

    Widnall, S. E.

    1972-01-01T23:59:59.000Z

    An open-jet wind tunnel operating within an anechoic chamber was developed for the purpose of the study of V/STOL noise mechanisms. An existing low-speed conventional hard-walled wind tunnel was modified to operate as an ...

  7. Attoclock time and exit momentum in strong-field tunnel ionization

    E-Print Network [OSTI]

    Teeny, Nicolas; Bauke, Heiko; Keitel, Christoph H

    2015-01-01T23:59:59.000Z

    Tunnel ionization belongs to the fundamental processes of atomic physics. The so-called two-step model, which describes the ionization as instantaneous tunneling at electric field maximum and classical motion afterwards, is commonly employed to describe tunnel ionization in adiabatic regimes. In this contribution, we first show by solving numerically the time-dependent Schr\\"odinger equation in one dimension that there is a time delay between the electric field maximum and the maximum of the ionization rate. This delay is identified as the response time needed by the wavefunction to react to the field maximum. Furthermore, there is a difference between the quantum momentum and the classical momentum from the two-step model after interaction with the driving electric field. Combining both results, we conclude that the electron has an effective initial momentum at the tunneling exit. Our results imply that the two-step model needs modification. The electron's initial momentum has to be incorporated, when tunnel...

  8. Tunneling Hamiltonian representation of false vacuum decay I. Comparison with the Bogomil'nyi inequality

    E-Print Network [OSTI]

    A. W. Beckwith

    2004-10-08T23:59:59.000Z

    The tunneling Hamiltonian has proven to be a useful method in many body physics to treat particle tunneling between different states represented as wave functions. Here we present a generalization of the tunneling Hamiltonian to quantum field theory, in which tunneling between states represented as wave functionals of a scalar quantum field is considered. We examine quantum decay of the false vacuum in the driven Sine-Gordon system, and show it is consistent with the tunneling formalism derived here and matches up with the soliton - anti soliton separation obtained from the Bogomil'nyi inequality. This inequality permits construction of a gaussian wave functional representation of soliton - anti soliton nucleated states and is consistent with respect to the false vacuum hypothesis

  9. Band Offsets of InGaP/GaAs Heterojunctions by Scanning Tunneling Spectroscopy Y. Dong and R. M. Feenstra

    E-Print Network [OSTI]

    Feenstra, Randall

    1 Band Offsets of InGaP/GaAs Heterojunctions by Scanning Tunneling Spectroscopy Y. Dong and R. M Abstract Scanning tunneling microscopy and spectroscopy are used to study InGaP/GaAs heterojunctions computation of the tunnel current. Curve fitting of theory to experiment is performed. Using an InGaP band gap

  10. Axial Ge/Si nanowire heterostructure tunnel FETs.

    SciTech Connect (OSTI)

    Dayeh, Shadi A. (Los Alamos National Laboratory); Gin, Aaron V.; Huang, Jian Yu; Picraux, Samuel Thomas (Los Alamos National Laboratory)

    2010-03-01T23:59:59.000Z

    Axial Ge/Si heterostructure nanowires (NWs) allow energy band-edge engineering along the axis of the NW, which is the charge transport direction, and the realization of asymmetric devices for novel device architectures. This work reports on two significant advances in the area of heterostructure NWs and tunnel FETs: (i) the realization of 100% compositionally modulated Si/Ge axial heterostructure NWs with lengths suitable for device fabrication and (ii) the design and implementation of Schottky barrier tunnel FETs on these NWs for high-on currents and suppressed ambipolar behavior. Initial prototype devices with 10 nm PECVD SiN{sub x} gate dielectric resulted in a very high current drive in excess of 100 {micro}A/{micro}m (I/{pi}D) and 10{sup 5} I{sub on}/I{sub off} ratios. Prior work on the synthesis of Ge/Si axial NW heterostructures through the VLS mechanism have resulted in axial Si/Si{sub 1-x}Ge{sub x} NW heterostructures with x{sub max} {approx} 0.3, and more recently 100% composition modulation was achieved with a solid growth catalyst. In this latter case, the thickness of the heterostructure cannot exceed few atomic layers due to the slow axial growth rate and concurrent radial deposition on the NW sidewalls leading to a mixture of axial and radial deposition, which imposes a big challenge for fabricating useful devices form these NWs in the near future. Here, we report the VLS growth of 100% doping and composition modulated axial Ge/Si heterostructure NWs with lengths appropriate for device fabrication by devising a growth procedure that eliminates Au diffusion on the NW sidewalls and minimizes random kinking in the heterostructure NWs as deduced from detailed microscopy analysis. Fig. 1 a shows a cross-sectional SEM image of epitaxial Ge/Si axial NW heterostructures grown on a Ge(111) surface. The interface abruptness in these Ge/Si heterostructure NWs is of the order of the NW diameter. Some of these NWs develop a crystallographic kink that is {approx}20{sup o} off the <111> axis at about 300 nm away from the Ge/Si interface. This provides a natural marker for placing the gate contact electrodes and gate metal at appropriate location for desired high-on current and reduced ambipolarity as shown in Fig. 2. The 1D heterostructures allow band-edge engineering in the transport direction, not easily accessible in planar devices, providing an additional degree of freedom for designing tunnel FETs (TFETs). For instance, a Ge tunnel source can be used for efficient electron/hole tunneling and a Si drain can be used for reduced back-tunneling and ambipolar behavior. Interface abruptness on the other hand (particularly for doping) imposes challenges in these structures and others for realizing high performance TFETs in p-i-n junctions. Since the metal-semiconductor contacts provide a sharp interface with band-edge control, we use properly designed Schottky contacts (aided by 3D Silvaco simulations) as the tunnel barriers both at the source and drain and utilize the asymmetry in the Ge/Si channel bandgap to reduce ambipolar transport behavior generally observed in TFETs. Fig. 3 shows the room-temperature transfer curves of a Ge/Si heterostructure TFET (H-TFET) for different V{sub DS} values showing a maximum on-current of {approx}7 {micro}A, {approx}170 mV/decade inverse subthreshold slope and 5 orders of magnitude I{sub on}/I{sub off} ratios for all V{sub DS} biases considered here. This high on-current value is {approx}1750 X higher than that obtained with Si p-i-n{sup +} NW TFETs and {approx}35 X higher than that obtained with CNT TFET. The I{sub on}/I{sub off} ratio and inverse subthreshold slope compare favorably to that of Si {approx} 10{sup 3} I{sub on}/I{sub off} and {approx} 800 mV/decade SS{sup -1} but lags behind those of CNT TFET due to poor PECVD nitride gate oxide quality ({var_epsilon}{sub r} {approx} 3-4). The asymmetry in the Schottky barrier heights used here eliminates the stringent requirements of abrupt doped interfaces used in p-i-n based TFETs, which is hard to achieve both in thin-film and

  11. Hawking radiation as tunneling from charged black holes in 0A string theory

    E-Print Network [OSTI]

    Hongbin Kim

    2011-07-22T23:59:59.000Z

    There has been much work on explaining Hawking radiation as a quantum tunneling process through horizons. Basically, this intuitive picture requires the calculation of the imaginary part of the action for outgoing particle. And two ways are known for achieving this goal: the null-geodesic method and the Hamilton-Jacobi method. We apply these methods to the charged black holes in 2D dilaton gravity which is originated from the low energy effective theory of type 0A string theory. We derive the correct Hawking temperature of the black holes including the effect of the back reaction of the radiation, and obtain the entropy by using the 1st law of black hole thermodynamics. For fixed-charge ensemble, the 0A black holes are free of phase transition and thermodynamically stable regardless of mass-charge ratio. We show this by interpreting the back reaction term as the inverse of the heat capacity of the black holes. Finally, the possibility of the phase transition in the fixed-potential ensemble is discussed.

  12. Radioactive air emissions notice of construction for deactivation of the PUREX storage tunnel number 2

    SciTech Connect (OSTI)

    JOHNSON, R.E.

    1999-10-11T23:59:59.000Z

    The Plutonium-Uranium Extraction (PUREX) Plant Storage Tunnel Number 2 (hereafter referred to as the PUREX Tunnel) was built in 1964. Since that time, the PUREX Tunnel has been used for storage of radioactive and mixed waste. In 1991, the PUREX Plant ceased operations and was transitioned to deactivation. The PUREX Tunnel continued to receive PUREX Plant waste material for storage during transition activities. Before 1995, a decision was made to store radioactive and mixed waste in the PUREX Tunnel generated from other onsite sources, on a case-by-case basis. This notice of construction (NOC) describes the activities associated with the reactivation of the PUREX Tunnel ventilation system and the transfer of up to 3.5 million curies (MCi) of radioactive waste to the PUREX Tunnel from any location on the Hanford Site. The unabated total effective dose equivalent (TEDE) estimated for the hypothetical offsite maximally exposed individual (MEI) is 5.6 E-2 millirem (mrem). The abated TEDE conservatively is estimated to account for 1.9 E-5 mrem to the MEI. The following text provides information requirements of Appendix A of Washington Administrative Code (WAC) 246-247 (requirements 1 through 18).

  13. Instability of superconducting state in Josephson tunnel junctions

    SciTech Connect (OSTI)

    Nevirkovets, I.P.; Rudenko, =.M.

    1984-02-01T23:59:59.000Z

    Experiments on low-resistance Josephson Sn--I--Sn tunnel junctions have shown the superconductor to exhibit an instability that manifests itself on the current--voltage characteristic (IVC) in the form of a jumplike decrease of the voltage when it reaches a value 2..delta../e. When a weak magnetic field H is applied parallel to the junction plane and suppresses the nonstationary Josephson effect, the negative-slope IVC section vanishes. The H-dependent instability-current component, as well as the dc component of the Josephson current near 2..delta../e, can be approximated by a function of H/sup -2/. The singularity observed is attributed to the presence of a maximum of the superconducting component, due to the Riedel singularity, at V = 2..delta../e.

  14. Relativistic tunneling picture of electron-positron pair creation

    E-Print Network [OSTI]

    Anton Wöllert; Michael Klaiber; Heiko Bauke; Christoph H. Keitel

    2015-03-19T23:59:59.000Z

    The common tunneling picture of electron-positron pair creation in a strong electric field is generalized to pair creation in combined crossed electric and magnetic fields. This enhanced picture, being symmetric for electrons and positrons, is formulated in a gauge-invariant and Lorentz-invariant manner for quasistatic fields. It may be used to infer qualitative features of the pair creation process. In particular, it allows for an intuitive interpretation of how the presence of a magnetic field modifies and, in particular cases, even enhances pair creation. The creation of electrons and positrons from the vacuum may be assisted by an energetic photon, which can also be incorporated into this picture of pair creation.

  15. Linear nanometric tunnel junction sensors with exchange pinned sensing layer

    SciTech Connect (OSTI)

    Leitao, D. C., E-mail: dleitao@inesc-mn.pt; Silva, A. V.; Cardoso, S. [INESC-MN and IN, Rua Alves Redol 9, 1000-029 Lisboa (Portugal); Instituto Superior Técnico (IST), Universidade de Lisboa, Av. Rovisco Pais, 1000-029 Lisboa (Portugal); Ferreira, R.; Paz, E.; Deepack, F. L. [INL, Av. Mestre Jose Veiga, 4715-31 Braga (Portugal); Freitas, P. P. [INESC-MN and IN, Rua Alves Redol 9, 1000-029 Lisboa (Portugal); INL, Av. Mestre Jose Veiga, 4715-31 Braga (Portugal)

    2014-05-07T23:59:59.000Z

    Highly sensitive nanosensors with high spatial resolution provide the necessary features for high accuracy imaging of isolated magnetic nanoparticles. In this work, we report the fabrication and characterization of MgO-barrier magnetic tunnel junction nanosensors, with two exchange-pinned electrodes. The perpendicular magnetization configuration for field sensing is set using a two-step annealing process, where the second annealing temperature was optimized to yield patterned sensors responses with improved linearity. The optimized circular nanosensors show sensitivities up to 0.1%/Oe, larger than previously reported for nanometric sensors and comparable to micrometric spin-valves. Our strategy avoids the use of external permanent biasing or demagnetizing fields (large for smaller structures) to achieve a linear response, enabling the control of the linear operation range using only the stack and thus providing a small footprint device.

  16. Heat engine driven by three-body photon tunneling

    E-Print Network [OSTI]

    Latella, Ivan; Rubi, J Miguel; Biehs, Svend-Age; Ben-Abdallah, Philippe

    2015-01-01T23:59:59.000Z

    Near-field heat engines are devices that convert the evanescent thermal field supported by a primary source into usable mechanical energy. By analyzing the thermodynamic performance of three-body near-field heat engines, we demonstrate that the power they supply can be substantially larger than that of two-body systems, showing so their strong potential for energy harvesting. Theoretical limits for energy and entropy fluxes in three-body systems are discussed and compared with their corresponding two-body counterparts. Such considerations confirm that the thermodynamic availability in energy-conversion processes driven by three-body photon tunneling can exceed the thermodynamic availability in two-body systems.

  17. Theory of multiphoton and tunnel ionization in a bichromatic field

    SciTech Connect (OSTI)

    Bagulov, D. S., E-mail: bagulov-denis@yandex.ru [Novosibirsk State University (Russian Federation); Kotelnikov, I. A., E-mail: I.A.Kotelnikov@inp.nsk.ru [Russian Academy of Sciences, Siberian Branch, Budger Institute of Nuclear Physics (Russian Federation)

    2013-01-15T23:59:59.000Z

    The imaginary-time method [6, 7] is used to calculate the multiphoton and tunnel ionization probabilities for atoms in a laser radiation field part of which is converted into the second harmonic. We assume that the first harmonic has a linear or elliptical polarization and the second harmonic is polarized linearly, with its polarization vector making an arbitrary angle with that of the first harmonic. The mean momentum of the photoelectrons knocked out from atoms is shown to depend on the phase shift between the first and second harmonics and their mutual polarization and to be identically equal to zero for a monochromatic field. An important difference between the case of elliptical polarization and the case of linear polarization of both harmonics is the absence of conditions under which the conditions for dominance of one of the two generation mechanisms considered here can be identified during the generation of terahertz radiation from the region of optical breakdown in a gas.

  18. Charge confinement and Klein tunneling from doping graphene

    E-Print Network [OSTI]

    C. Popovici; O. Oliveira; W. de Paula; T. Frederico

    2012-02-14T23:59:59.000Z

    In the present work, we investigate how structural defects in graphene can change its transport properties. In particular, we show that breaking of the sublattice symmetry in a graphene monolayer overcomes the Klein effect, leading to confined states of massless Dirac fermions. Experimentally, this corresponds to chemical bonding of foreign atoms to carbon atoms, which attach themselves to preferential positions on one of the two sublattices. In addition, we consider the scattering off a tensor barrier, which describes the rotation of the honeycomb cells of a given region around an axis perpendicular to the graphene layer. We demonstrate that in this case the intervalley mixing between the Dirac points emerges, and that Klein tunneling occurs.

  19. Isotope effect in tunnelling ionization of neutral hydrogen molecules

    E-Print Network [OSTI]

    Wang, X; Atia-Tul-Noor, A; Hu, B T; Kielpinski, D; Sang, R T; Litvinyuk, I V

    2015-01-01T23:59:59.000Z

    It has been recently predicted theoretically that due to nuclear motion light and heavy hydrogen molecules exposed to strong electric field should exhibit substantially different tunneling ionization rates (O.I. Tolstikhin, H.J. Worner and T. Morishita, Phys. Rev. A 87, 041401(R) (2013) [1]). We studied that isotope effect experimentally by measuring relative ionization yields for each species in a mixed H2/D2 gas jet interacting with intense femtosecond laser pulses. In a reaction microscope apparatus we detected ionic fragments from all contributing channels (single ionization, dissociation, and sequential double ionization) and determined the ratio of total single ionization yields for H2 and D2. The measured ratio agrees quantitatively with the prediction of the generalized weak-field asymptotic theory in an apparent failure of the frozen-nuclei approximation.

  20. High energy storage capacitor by embedding tunneling nano-structures

    DOE Patents [OSTI]

    Holme, Timothy P; Prinz, Friedrich B; Van Stockum, Philip B

    2014-11-04T23:59:59.000Z

    In an All-Electron Battery (AEB), inclusions embedded in an active region between two electrodes of a capacitor provide enhanced energy storage. Electrons can tunnel to/from and/or between the inclusions, thereby increasing the charge storage density relative to a conventional capacitor. One or more barrier layers is present in an AEB to block DC current flow through the device. The AEB effect can be enhanced by using multi-layer active regions having inclusion layers with the inclusions separated by spacer layers that don't have the inclusions. The use of cylindrical geometry or wrap around electrodes and/or barrier layers in a planar geometry can enhance the basic AEB effect. Other physical effects that can be employed in connection with the AEB effect are excited state energy storage, and formation of a Bose-Einstein condensate (BEC).

  1. An analysis of three nuclear events in P-Tunnel

    SciTech Connect (OSTI)

    Fourney, W.L.; Dick, R.D. [Maryland Univ., College Park, MD (United States); Taylor, S.R.; Weaver, T.A. [Los Alamos National Lab., NM (United States)

    1994-05-03T23:59:59.000Z

    This report examines experimental results obtained from three P Tunnel events -- Mission Cyber, Disko Elm, and Distant Zenith. The objective of the study was to determine if there were any differences in the explosive source coupling for the three events. It was felt that Mission Cyber might not have coupled well because the ground motions recorded for that event were much lower than expected based on experience from N Tunnel. Detailed examination of the physical and chemical properties of the tuff in the vicinity of each explosion indicated only minor differences. In general, the core samples are strong and competent out to at least 60 m from each working point. Qualitative measures of core sample strength indicate that the strength of the tuff near Mission Cyber may be greater than indicated by results of static testing. Slight differences in mineralogic content and saturation of the Mission Cyber tuff were noted relative to the other two tests, but probably would not result in large differences in ground motions. Examination of scaled free-field stress and acceleration records collected by Sandia National Laboratory (SNL) indicated that Disko Elm showed the least scatter and Distant Zenith the most scatter. Mission Cyber measurements tend to lie slightly below those of Distant Zenith, but still within two standard deviations. Analysis of regional seismic data from networks operated by Lawrence Livermore National Laboratory (LLNL) and SNL also show no evidence of Mission Cyber coupling low relative to the other two events. The overall conclusion drawn from the study is that there were no basic differences in the way that the explosions coupled to the rock.

  2. Atomic-scale Authentication Using Resonant Tunnelling Diodes

    E-Print Network [OSTI]

    J. Roberts; I. E. Bagci; M. A. M. Zawawi; J. Sexton; N. Hulbert; Y. J. Noori; M. P. Young; C. S. Woodhead; M. Missous; M. A. Migliorato; U. Roedig; R. J. Young

    2015-02-23T23:59:59.000Z

    The rapid development of technology has provided a wealth of resources enabling the trust of everyday interactions to be undermined. Authentication schemes aim to address this challenge by providing proof of identity. This can be achieved by using devices that, when challenged, give unique but reproducible responses. At present, these distinct signatures are commonly generated by physically unclonable functions, or PUFs. These devices provide a straightforward measurement of a physical characteristic of their structure that has inherent randomness, due to imperfections in the manufacturing process. These hard-to-predict physical responses can generate a unique identity that can be used for authentication without relying on the secrecy of stored data. However, the classical design of these devices limits both their size and security. Here we show that the extensively studied problematic fluctuations in the current-voltage measurements of resonant tunnelling diodes (RTDs) provide an uncomplicated, robust measurement that can function as a PUF without conventional resource limitations. This is possible due to quantum tunnelling within the RTD, and on account of these room temperature quantum effects, we term such devices QUFs - quantum unclonable functions. As a result of the current-voltage spectra being dependent on the atomic structure and composition of the nanostructure within the RTD, each device provides a high degree of uniqueness, whilst being impossible to clone or simulate, even with state-of-the-art technology. We have thus created PUF-like devices requiring the fewest resources which make use of quantum phenomena in a highly manufacturable electronic device operating at room temperature. Conventional spectral analysis techniques, when applied to our QUFs, will enable reliable generation of unpredictable unique identities which can be employed in advanced authentication systems.

  3. New Coordinates for BTZ Black Hole and Hawking Radiation via Tunnelling

    E-Print Network [OSTI]

    Wenbiao Liu

    2005-12-16T23:59:59.000Z

    Hawking radiation can usefully be viewed as a semi-classical tunnelling process that originates at the black hole horizon. For the stationary axisymmetric BTZ black hole, a generalized Painleve coordinate system (Painleve-BTZ coordinates) is introduced, and Hawking radiation as tunnelling under the effect of self-gravitation is investigated. The corrected radiation is obtained which is not precise thermal spectrum. The result is consistent with the underlying unitary theory. Moreover, Bekenstein-Hawking entropy of BTZ black hole is not necessarily corrected when we choose appropriate coordinate system to study the tunnelling effect.

  4. Imaging of buried phosphorus nanostructures in silicon using scanning tunneling microscopy

    SciTech Connect (OSTI)

    Oberbeck, Lars [Centre for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); TOTAL Marketing Services, New Energies, La Défense 10, 92069 Paris La Défense Cedex (France); Reusch, Thilo C. G.; Hallam, Toby; Simmons, Michelle Y., E-mail: n.curson@ucl.ac.uk, E-mail: michelle.simmons@unsw.edu.au [Centre for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); Schofield, Steven R. [Centre for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); London Centre for Nanotechnology, UCL, London WC1H 0AH (United Kingdom); Department of Physics and Astronomy, UCL, London WC1E 6BT (United Kingdom); Curson, Neil J., E-mail: n.curson@ucl.ac.uk, E-mail: michelle.simmons@unsw.edu.au [Centre for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); London Centre for Nanotechnology, UCL, London WC1H 0AH (United Kingdom); Department of Electronic and Electrical Engineering, UCL, London WC1E 7JE (United Kingdom)

    2014-06-23T23:59:59.000Z

    We demonstrate the locating and imaging of single phosphorus atoms and phosphorus dopant nanostructures, buried beneath the Si(001) surface using scanning tunneling microscopy. The buried dopant nanostructures have been fabricated in a bottom-up approach using scanning tunneling microscope lithography on Si(001). We find that current imaging tunneling spectroscopy is suited to locate and image buried nanostructures at room temperature and with residual surface roughness present. From these studies, we can place an upper limit on the lateral diffusion during encapsulation with low-temperature Si molecular beam epitaxy.

  5. The monitoring of an existing cast iron tunnel with distributed fibre optic sensing (DFOS)

    E-Print Network [OSTI]

    Gue, C. Y.; Wilcock, M.; Alhaddad, M. M.; Elshafie, M. Z. E. B.; Soga, K.; Mair, R. J.

    2015-03-29T23:59:59.000Z

    and the tunnel still remains closed. Since the Royal Mail tunnel is disused, it presented an ideal trial site for various state-of-the-art monitoring systems to be tested. 2.1.2 Mode of deformation One of the main uncertainties design engineers face when... lining tunnel in the longitudinal direction. (After Alhaddad et al. [1]) J Civil Struct Health Monit 123 risk of creep. Furthermore, having multiple protective layers and coatings increases the complexity of working with the cable on site, i.e. stripping...

  6. The effect of environmental coupling on tunneling of quasiparticles in Josephson junctions

    E-Print Network [OSTI]

    Mohammad H. Ansari; Frank K. Wilhelm; Urbasi Sinha; Aninda Sinha

    2013-11-07T23:59:59.000Z

    We study quasiparticle tunneling in Josephson tunnel junctions embedded in an electromagnetic environment. We identify tunneling processes that transfer electrical charge and couple to the environment in a way similar to that of normal electrons, and processes that mix electrons and holes and are thus creating charge superpositions. The latter are sensitive to the phase difference between the superconductor and are thus limited by phase diffusion even at zero temperature. We show that the environmental coupling is suppressed in many environments, thus leading to lower quasiparticle decay rates and thus better superconductor qubit coherence than previously expected. Our approach is nonperturbative in the environmental coupling strength.

  7. Assignment Types UTS LIBRARY

    E-Print Network [OSTI]

    University of Technology, Sydney

    Assignment Types UTS LIBRARY February 2013 Academic Writing Guide Part 2 ­ Assignment Types: This section outlines the basic types of written assignments, providing structural elements and examples. #12;2 II. Assignment Types 1. Essay Writing

  8. Evaluation of analytical methods to interpret ground deformations due to soft ground tunneling

    E-Print Network [OSTI]

    Zymnis, Despina M

    2009-01-01T23:59:59.000Z

    An in depth study was undertaken to evaluate the effectiveness of analytical solutions in describing ground movements induced by soft ground tunneling. The analytical solutions that were examined consider both isotropic ...

  9. Wind Tunnel and Flight Testing of Active Flow Control on a UAV

    E-Print Network [OSTI]

    Babbar, Yogesh

    2011-08-08T23:59:59.000Z

    Active flow control has been extensively explored in wind tunnel studies but successful in-flight implementation of an active flow control technology still remains a challenge. This thesis presents implementation of active flow control technology...

  10. A New Scanning Tunneling Microscope Reactor Used for High Pressure and High Temperature Catalysis Studies

    E-Print Network [OSTI]

    Tao, Feng

    2009-01-01T23:59:59.000Z

    bowl glued at the end of the scanning tube. The arrowbowl at the end of the scanning tube. FIG. 6. (a) STM imageA New Scanning Tunneling Microscope Reactor Used for High

  11. Common-path interference and oscillatory Zener tunneling in bilayer graphene p-n junctions

    E-Print Network [OSTI]

    Nandkishore, Rahul Mahajan

    Interference and tunneling are two signature quantum effects that are often perceived as the yin and yang of quantum mechanics: a particle simultaneously propagating along several distinct classical paths versus a particle ...

  12. Wind Tunnel Tests of Parabolic Trough Solar Collectors: March 2001--August 2003

    SciTech Connect (OSTI)

    Hosoya, N.; Peterka, J. A.; Gee, R. C.; Kearney, D.

    2008-05-01T23:59:59.000Z

    Conducted extensive wind-tunnel tests on parabolic trough solar collectors to determine practical wind loads applicable to structural design for stress and deformation, and local component design for concentrator reflectors.

  13. Fire Size and Fire Spread in Tunnels with Longitudinal Ventilation Systems. 

    E-Print Network [OSTI]

    Carvel, Ricky O; Beard, Alan; Jowitt, P W; Drysdale, Dougal

    2005-01-01T23:59:59.000Z

    The results and findings of three previous research projects are combined with new research to estimate the overall influence of longitudinal ventilation on fire size and spread in tunnels. Each of the three previous projects is briefly described...

  14. Propeller design optimization for tunnel bow thrusters in the bollard pull condition

    E-Print Network [OSTI]

    Wilkins, James R., IV

    2012-01-01T23:59:59.000Z

    Tunnel bow thrusters are often used by large ships to provide low-speed lateral maneuverability when docking. Required to provide high thrust while essentially at a standstill, the design point for these thrusters is the ...

  15. Instanton-noninstanton transition in nonintegrable tunneling processes: A renormalized perturbation approach

    E-Print Network [OSTI]

    Akira Shudo; Yasutaka Hanada; Teruaki Okushima; Kensuke S. Ikeda

    2015-03-02T23:59:59.000Z

    The instanton-noninstanton (I-NI) transition in the tunneling process, which has been numerically observed in classically nonintegrable quantum maps, can be described by a perturbation theory based on an integrable Hamiltonian renormalized so as to incorporate the integrable part of the map. The renormalized perturbation theory is successfully applied to the two quantum maps, the H\\'enon and standard maps. In spite of different nature of tunneling in the two systems, the I-NI transition exhibits very common characteristics. In particular, the manifestation of I-NI transition is obviously explained by a remarkable quenching of the renormalized transition matrix element. The enhancement of tunneling probability after the transition can be understood as a sudden change of the tunneling mechanism from the instanton to quite a different mechanism supported by classical flows just outside of the stable-unstable manifolds of the saddle on the top of the potential barrier.

  16. Titanium Silicide Islands on Atomically Clean Si(100): Identifying Single Electron Tunneling Effects

    E-Print Network [OSTI]

    Joseph L. Tedesco; J. E. Rowe; Robert J. Nemanich

    2010-07-28T23:59:59.000Z

    Titanium silicide islands have been formed by the ultrahigh vacuum deposition of thin films of titanium (electron tunneling (SET) according to the orthodox model of SET. Some of the islands formed are small enough (diameter reliability of future devices.

  17. Structural Fluctuations, Spin, Reorganization Energy, and Tunneling Energy Control of Intramolecular Electron Transfer

    E-Print Network [OSTI]

    Kurnikova, Maria

    calculations of electronic couplings, molecular dynamics simulations of molecular geometries, and Poisson exists to interpret electron-transfer (ET) reactions and their dependence upon molecular structure.1Structural Fluctuations, Spin, Reorganization Energy, and Tunneling Energy Control

  18. Investigation of the tunneling emitter bipolar transistor as spin-injector into silicon

    E-Print Network [OSTI]

    Van Veenhuizen, Marc Julien

    2010-01-01T23:59:59.000Z

    In this thesis is discussed the tunneling emitter bipolar transistor as a possible spin-injector into silicon. The transistor has a metallic emitter which as a spin-injector will be a ferromagnet. Spin-polarized electrons ...

  19. A Study of Fire Durability for a Road Tunnel: Comparing CFD and Simple Analytical Models 

    E-Print Network [OSTI]

    Reszka, Pedro; Steinhaus, Thomas; Biteau, Hubert; Carvel, Ricky O; Rein, Guillermo; Torero, Jose L

    The durability of various typical tunnel sections in the event of a prescribed 100 MW fire has been assessed. Cast-iron sections, pre-cast concrete sections and in-situ concrete cut and cover sections are all considered ...

  20. Tunnel determinants from spectral zeta functions. Instanton effects in quantum mechanics

    SciTech Connect (OSTI)

    Izquierdo, A. Alonso [Departamento de Matematica Aplicada and IUFFyM, Universidad de Salamanca (Spain); Guilarte, J. Mateos [Departamento de Fisica Fundamental and IUFFyM, Universidad de Salamanca (Spain)

    2014-07-23T23:59:59.000Z

    In this paper we develop an spectral zeta function regularization procedure on the determinants of instanton fluctuation operators that describe the semi-classical order of tunnel effects between degenerate vacua.

  1. Earth pressure balance (EPB) tunneling induced settlements in the Tren Urbano Project, Rio Piedras, Puerto Rico

    E-Print Network [OSTI]

    Abrams, Alejandro J

    2007-01-01T23:59:59.000Z

    Underground construction of the Rio Piedras section of the Tren Urbano project involved the construction of twin tunnels (6.3m diameter) with Earth Pressure Balance machines in weathered alluvial soil. The depth of the ...

  2. The tunneling hamiltonian representation of false vacuum decay: III. Application to nucleation of an inflationary universe

    E-Print Network [OSTI]

    A. W. Beckwith

    2004-07-12T23:59:59.000Z

    The tunneling hamiltonian has proven to be a useful method in many body physics to treat particle tunneling between different states represented as wave functions. Here we apply a generalization of a way we formed appropriate wave functionals in CDW to how to present nucleation of an inflationary universe . This allows us to make a generalization of the model used for inflation when the inflaton is trapped in a false vacuum and, after tunneling, makes a first order phase transition to initiate nucleation of an inflationary universe, in which tunneling between states which are wavefunctionals of a scalar quantum field are considered . We explain how we can have particle - anti particle pairs as a model for how nucleation occurs and construct a potential which satisfies the flat slow roll condition even while using a modified false vacuum construction to this problem

  3. Fire modeling for Building 221-T - T Plant Canyon Deck and Railroad Tunnel

    SciTech Connect (OSTI)

    Oar, D.L.

    1994-09-29T23:59:59.000Z

    This report was prepared by Hughes Associates, Inc. to document the results of fire models for building 221-T Canyon Deck and Railroad Tunnel. Backup data is contained in document No. WHC-SD-CP-ANAL-010, Rev. 0.

  4. Tunnel Boring Machine (TBM) performance in Singapore's Mass Rapid Transit (MRT) system

    E-Print Network [OSTI]

    Chong, Wanling

    2013-01-01T23:59:59.000Z

    Singapore's Mass Rapid Transit (MRT) network is one of the largest public works projects undertaken by the Singapore government. This thesis summarizes and evaluates the performance of Tunnel Boring Machine (TBM) construction ...

  5. An Updated Procedure for Tare and Interference Wind Tunnel Testing of Strut-Mounted Models

    E-Print Network [OSTI]

    Kutz, Douglas M

    2014-05-02T23:59:59.000Z

    to the presence of wind tunnel walls. The standard correction procedure adjusts for the presence of these boundaries using approximations based on linear potential flow theory. Separately,tare and interference removal involves the linear subtraction of mounting...

  6. Types of Costs Types of Cost Estimates

    E-Print Network [OSTI]

    Boisvert, Jeff

    · Types of Costs · Types of Cost Estimates · Methods to estimate capital costs MIN E 408: Mining% accuracy. ­ 2-5% of pre-production capital Types of Cost Estimates #12;3. Definitive ­ Based on definitive-even $ Production Level Fixed Cost Break-even $ Production Level Cost-Revenue Relationships · Capital Costs (or

  7. Preliminary studies of tunnel interface response modeling using test data from underground storage facilities.

    SciTech Connect (OSTI)

    Sobolik, Steven Ronald; Bartel, Lewis Clark

    2010-11-01T23:59:59.000Z

    In attempting to detect and map out underground facilities, whether they be large-scale hardened deeply-buried targets (HDBT's) or small-scale tunnels for clandestine border or perimeter crossing, seismic imaging using reflections from the tunnel interface has been seen as one of the better ways to both detect and delineate tunnels from the surface. The large seismic impedance contrast at the tunnel/rock boundary should provide a strong, distinguishable seismic response, but in practice, such strong indicators are often lacking. One explanation for the lack of a good seismic reflection at such a strong contrast boundary is that the damage caused by the tunneling itself creates a zone of altered seismic properties that significantly changes the nature of this boundary. This report examines existing geomechanical data that define the extent of an excavation damage zone around underground tunnels, and the potential impact on rock properties such as P-wave and S-wave velocities. The data presented from this report are associated with sites used for the development of underground repositories for the disposal of radioactive waste; these sites have been excavated in volcanic tuff (Yucca Mountain) and granite (HRL in Sweden, URL in Canada). Using the data from Yucca Mountain, a numerical simulation effort was undertaken to evaluate the effects of the damage zone on seismic responses. Calculations were performed using the parallelized version of the time-domain finitedifference seismic wave propagation code developed in the Geophysics Department at Sandia National Laboratories. From these numerical simulations, the damage zone does not have a significant effect upon the tunnel response, either for a purely elastic case or an anelastic case. However, what was discovered is that the largest responses are not true reflections, but rather reradiated Stoneley waves generated as the air/earth interface of the tunnel. Because of this, data processed in the usual way may not correctly image the tunnel. This report represents a preliminary step in the development of a methodology to convert numerical predictions of rock properties to an estimation of the extent of rock damage around an underground facility and its corresponding seismic velocity, and the corresponding application to design a testing methodology for tunnel detection.

  8. Shock-Dispersed-Fuel Charges: Combustion in Chambers and Tunnels

    SciTech Connect (OSTI)

    Neuwald, P; Reichenbach, H; Kuhl, A L

    2003-04-22T23:59:59.000Z

    In previous studies we have investigated after-burning effects of a fuel-rich explosive (TNT). In that case the detonation only releases about 30% of the available energy, but generates a hot cloud of fuel that can burn in the ambient air, thus evoking an additional energy release that is distributed in space and time. The current series of small-scale experiments can be looked upon as a natural generalization of this mechanism: a booster charge disperses a (non-explosive) fuel, provides mixing with air and, by means of the hot detonation products, the energy to ignite the fuel. The current version of our miniature Shock-Dispersed-Fuel (SDF) charges consists of a spherical booster charge of 0.5 g PETN, embedded in a paper cylinder of approximately 2.2 cm, which is filled with powdered fuel compositions. The main compositions studied up to now contain aluminum flakes, hydrocarbon powders like polyethylene or hexosen (sucrose) and/or carbon particles. These charges were studied in four different chambers: two cylindrical vessels of 6.6-1 and 40.5-1 volume with a height-to-diameter ratio of approximately 1, a rectangular chamber of 41 (10.5 x 10.5 x 38.6 cm) and a 299.6 cm long tunnel model with a cross section of 8 x 8 cm (volume 19.21) closed at both ends.

  9. Tunnel studies of niobium films containing excess quasiparticles

    SciTech Connect (OSTI)

    Pan, V.M.; Rudenko, E.M.; Nevirkovets, I.P.; Shaternik, V.E.

    1982-12-01T23:59:59.000Z

    The instability of the nonequilibrium state in superconducting niobium films is studied for wide-band (eV>3..delta..) and narrow-band (..delta..>>eV-3..delta..) sources of quasiparticles injected into the film. For a wide-band source, the critical instability current I/sub i/ was found to vary anomalously with the helium bath temperature. The pulse technique was used to measure the local heating temperature T/sub l/ in the neighborhood of a tunnel contact. The variation of I/sub i/ with T/sub l/ is not anomalous and is consistent with the theoretical temperature dependence ..beta../sub c/(T) of the critical power (V. F. Elesin, V. E. Kondrashov, and A. S. Sukhikh, Sov. Phys. Solid State 21, 1861 (1979)). Instability is found for a narrow-band source for the contacts having the lowest resistance. The instability current in this case decreases with falling temperature, in qualitative agreement with the theory of threshold instability in a superconductor.

  10. Klein tunneling and supercollimation of pseudospin-1 photons

    E-Print Network [OSTI]

    Fang, A; Louie, Steven G; Chan, C T

    2015-01-01T23:59:59.000Z

    Pseudospin plays a central role in many novel physical properties of graphene and other artificial systems which have pseudospins of 1/2. Here we show that in certain photonic crystals (PCs) exhibiting conical dispersions at k = 0, the eigenmodes near the "Dirac-like point" can be described by an effective spin-orbit Hamiltonian with a pseudospin of 1, treating wave propagations in the upper cone, the lower cone and a flat band (corresponding to zero refractive index) within a unified framework. The 3-component spinor gives rise to boundary conditions distinct from those of pseudospin-1/2, leading to new wave transport behaviors as manifested in Klein tunneling and supercollimation. For example, collimation can be realized more easily with pseudospin-1 than pseudospin-1/2. The special wave scattering properties of pseudospin-1 photons, coupled with the discovery that the effective photonic "potential" can be varied by a simple change of length scale, may offer new ways to control photon transport.

  11. Potential for tunneling based on rock and soil melting. Abstracts

    SciTech Connect (OSTI)

    Rowley, J.C.

    1985-01-01T23:59:59.000Z

    The rock-melting drill was invented at Los Alamos Scientific Laboratory in 1960. Electrically heated, laboratory-scale drills were subsequently shown to penetrate igneous rocks at usefully high rates, with moderate power consumptions. The development of compact nuclear reactors and of heat pipes now makes possible the extension of this technology to much larger melting penetrators, potentially capable of producing holes up to several meters in diameter and several tens of kilometers long or deep. Development of a rapid, versatile, economical method of boring large, long shafts and tunnels offers solutions to many of man's most urgent ecological, scientific, raw-materials, and energy-supply problems. A melting method appears to be the most promising and flexible means of producing such holes. It is relatively insensitive to the composition, hardness, structure, and temperature of the rock, and offers the possibilities of producing self-supporting, glass-lined holes in almost any formation and (using a technique called lithofracturing) of eliminating the debris-removal problem by forcing molten rock into cracks created in the bore wall. Large rock-melting penetrators, called Electric Subterrenes or Nuclear Subterrenes according to the energy source used, are discussed in this report, together with problems anticipated in their development. It is concluded that this development is within the grasp of present technology.

  12. An Scanning Tunneling Microscopy and Photoelectron Spectroscopy Study of Pattern Formation and Molecule Ordering under a Variety of Interactions

    E-Print Network [OSTI]

    Zhu, Yeming

    2013-01-01T23:59:59.000Z

    Chen, Introduction to Scanning Tunneling Microscopy, Oxfordvoltages to search the scanning area on the surface. Threecontrol system for scanning tun- neling microscope (STM)

  13. Types of Commissioning

    Broader source: Energy.gov [DOE]

    Several commissioning types exist to address the specific needs of equipment and systems across both new and existing buildings. The following commissioning types provide a good overview.

  14. Performance limits of tunnel transistors based on mono-layer transition-metal dichalcogenides

    SciTech Connect (OSTI)

    Jiang, Xiang-Wei, E-mail: xwjiang@semi.ac.cn; Li, Shu-Shen [State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-05-12T23:59:59.000Z

    Performance limits of tunnel field-effect transistors based on mono-layer transition metal dichalcogenides are investigated through numerical quantum mechanical simulations. The atomic mono-layer nature of the devices results in a much smaller natural length ?, leading to much larger electric field inside the tunneling diodes. As a result, the inter-band tunneling currents are found to be very high as long as ultra-thin high-k gate dielectric is possible. The highest on-state driving current is found to be close to 600??A/?m at V{sub g}?=?V{sub d}?=?0.5?V when 2?nm thin HfO{sub 2} layer is used for gate dielectric, outperforming most of the conventional semiconductor tunnel transistors. In the five simulated transition-metal dichalcogenides, mono-layer WSe{sub 2} based tunnel field-effect transistor shows the best potential. Deep analysis reveals that there is plenty room to further enhance the device performance by either geometry, alloy, or strain engineering on these mono-layer materials.

  15. Attoclock time and exit momentum in strong-field tunnel ionization

    E-Print Network [OSTI]

    Nicolas Teeny; Enderalp Yakaboylu; Heiko Bauke; Christoph H. Keitel

    2015-02-20T23:59:59.000Z

    Tunnel ionization belongs to the fundamental processes of atomic physics. The so-called two-step model, which describes the ionization as instantaneous tunneling at electric field maximum and classical motion afterwards, is commonly employed to describe tunnel ionization in adiabatic regimes. In this contribution, we first show by solving numerically the time-dependent Schr\\"odinger equation in one dimension that there is a time delay between the electric field maximum and the maximum of the ionization rate. This delay is identified as the response time needed by the wavefunction to react to the field maximum. Furthermore, there is a difference between the quantum momentum and the classical momentum from the two-step model after interaction with the driving electric field. Combining both results, we conclude that the electron has an effective initial momentum at the tunneling exit. Our results imply that the two-step model needs modification. The electron's initial momentum has to be incorporated, when tunneling times shall be determined in attoclock experiments.

  16. Types of Costs Types of Cost Estimates

    E-Print Network [OSTI]

    Boisvert, Jeff

    05-1 · Types of Costs · Types of Cost Estimates · Methods to estimate capital costs MIN E 408-Revenue Relationships · Capital Costs (or first cost or capital investment): ­ Expenditures made to acquire or develop capital assets ­ Three main classes of capital costs: 1. Depreciable Investment: · Investment allocated

  17. Near-Region Modification of Total Pressure Fluctuations by a Normal Shock Wave in a Low-Density Hypersonic Wind Tunnel

    E-Print Network [OSTI]

    Mai, Chi Luong Nhat

    2014-05-01T23:59:59.000Z

    -density hypersonic wind tunnel. Measurements were obtained with a fast-response Pitot pressure probe traversing in the freestream direction. The tunnel freestream noise level was characterized and served as the inflow/upstream condition to the interaction...

  18. Subthreshold-swing physics of tunnel field-effect transistors Wei Cao, Deblina Sarkar, Yasin Khatami, Jiahao Kang, and Kaustav Banerjee

    E-Print Network [OSTI]

    Subthreshold-swing physics of tunnel field-effect transistors Wei Cao, Deblina Sarkar, Yasin) Subthreshold-swing physics of tunnel field-effect transistors Wei Cao, Deblina Sarkar, Yasin Khatami, Jiahao

  19. Antenna-coupled Photon Emission from hexagonal Boron Nitride Tunnel Junctions

    E-Print Network [OSTI]

    Parzefall, Markus; Jain, Achint; Watanabe, Kenji; Taniguchi, Takashi; Novotny, Lukas

    2015-01-01T23:59:59.000Z

    The ultrafast conversion of electrical to optical signals at the nanoscale is of fundamental interest for data processing, telecommunication and optical interconnects. However, the modulation bandwidths of semiconductor LEDs are limited by the spontaneous recombination rate of electron-hole pairs and the footprint of electrically-driven ultrafast lasers is too large for practical on-chip integration. A metal-insulator-metal (MIM) tunnel junction approaches the ultimate size limit of electronic devices and its operating speed is fundamentally limited only by the tunneling time. Here we study the conversion of electron energy - localized in vertical gold-h-BN-gold tunnel junctions - into free space photons, mediated by resonant slot antennas. Optical antennas efficiently bridge the size-mismatch between nanoscale volumes and far-field radiation and strongly enhance the electron-photon conversion efficiency. We achieve polarized, directional and resonantly enhanced light emission from inelastic electron tunnelin...

  20. Intermediate-band photosensitive device with quantum dots having tunneling barrier embedded in organic matrix

    DOE Patents [OSTI]

    Forrest, Stephen R. (Ann Arbor, MI)

    2008-08-19T23:59:59.000Z

    A plurality of quantum dots each have a shell. The quantum dots are embedded in an organic matrix. At least the quantum dots and the organic matrix are photoconductive semiconductors. The shell of each quantum dot is arranged as a tunneling barrier to require a charge carrier (an electron or a hole) at a base of the tunneling barrier in the organic matrix to perform quantum mechanical tunneling to reach the respective quantum dot. A first quantum state in each quantum dot is between a lowest unoccupied molecular orbital (LUMO) and a highest occupied molecular orbital (HOMO) of the organic matrix. Wave functions of the first quantum state of the plurality of quantum dots may overlap to form an intermediate band.

  1. Large-scale fabrication of BN tunnel barriers for graphene spintronics

    SciTech Connect (OSTI)

    Fu, Wangyang; Makk, Péter; Maurand, Romain; Bräuninger, Matthias; Schönenberger, Christian [Department of Physics, University of Basel, Basel (Switzerland)

    2014-08-21T23:59:59.000Z

    We have fabricated graphene spin-valve devices utilizing scalable materials made from chemical vapor deposition (CVD). Both the spin-transporting graphene and the tunnel barrier material are CVD-grown. The tunnel barrier is realized by Hexagonal boron nitride, used either as a monolayer or bilayer and placed over the graphene. Spin transport experiments were performed using ferromagnetic contacts deposited onto the barrier. We find that spin injection is still greatly suppressed in devices with a monolayer tunneling barrier due to resistance mismatch. This is, however, not the case for devices with bilayer barriers. For those devices, a spin relaxation time of ?260 ps intrinsic to the CVD graphene material is deduced. This time scale is comparable to those reported for exfoliated graphene, suggesting that this CVD approach is promising for spintronic applications which require scalable materials.

  2. Self Excitation of the Tunneling Scalar Field in False Vacuum Decay

    E-Print Network [OSTI]

    Takashi Hamazaki; Misao Sasaki; Takahiro Tanaka; Kazuhiro Yamamoto

    1995-07-04T23:59:59.000Z

    A method to determine the quantum state of a scalar field after $O(4)$-symmetric bubble nucleation has been developed recently. The method has an advantage that it concisely gives us a clear picture of the resultant quantum state. In particular, one may interpret the excitations as a particle creation phenomenon just as in the case of particle creation in curved spacetime. As an application, we investigate in detail the spectrum of quantum excitations of the tunneling field when it undergoes false vacuum decay. We consider a tunneling potential which is piece-wise quadratic, hence is simple enough to allow us an analytical treatment. We find a strong dependence of the excitation spectrum upon the shape of the potential on the true vacuum side. We then discuss features of the excitation spectrum common to general tunneling potentials not restricted to our simple model.

  3. Hawking radiation as tunneling from a Vaidya black hole in noncommutative gravity

    SciTech Connect (OSTI)

    Mehdipour, S. Hamid [Islamic Azad University, Lahijan Branch, P. O. Box 1616, Lahijan (Iran, Islamic Republic of)

    2010-06-15T23:59:59.000Z

    In the context of a noncommutative model of coordinate coherent states, we present a Schwarzschild-like metric for a Vaidya solution instead of the standard Eddington-Finkelstein metric. This leads to the appearance of an exact (t-r) dependent case of the metric. We analyze the resulting metric in three possible causal structures. In this setup, we find a zero remnant mass in the long-time limit, i.e. an instable black hole remnant. We also study the tunneling process across the quantum horizon of such a Vaidya black hole. The tunneling probability including the time-dependent part is obtained by using the tunneling method proposed by Parikh and Wilczek in terms of the noncommutative parameter {sigma}. After that, we calculate the entropy associated to this noncommutative black hole solution. However, the corrections are fundamentally trifling; one could respect this as a consequence of quantum inspection at the level of semiclassical quantum gravity.

  4. Giant amplification of tunnel magnetoresistance in a molecular junction: Molecular spin-valve transistor

    SciTech Connect (OSTI)

    Dhungana, Kamal B.; Pati, Ranjit, E-mail: patir@mtu.edu [Department of Physics, Michigan Technological University, Houghton, Michigan 49931 (United States)

    2014-04-21T23:59:59.000Z

    Amplification of tunnel magnetoresistance by gate field in a molecular junction is the most important requirement for the development of a molecular spin valve transistor. Herein, we predict a giant amplification of tunnel magnetoresistance in a single molecular spin valve junction, which consists of Ru-bis-terpyridine molecule as a spacer between two ferromagnetic nickel contacts. Based on the first-principles quantum transport approach, we show that a modest change in the gate field that is experimentally accessible can lead to a substantial amplification (320%) of tunnel magnetoresistance. The origin of such large amplification is attributed to the spin dependent modification of orbitals at the molecule-lead interface and the resultant Stark effect induced shift in channel position with respect to the Fermi energy.

  5. Tunneling density of states of high Tc superconductors d-wave BCS model vs. SU(2) slave boson model

    E-Print Network [OSTI]

    Wen, Xiao-Gang

    Tunneling density of states of high Tc superconductors d-wave BCS model vs. SU(2) slave boson model conductance curves in the superconducting state at zero temperature. Comparing the two results obtained via Tunneling spectroscopy has been one of the funda- mental tools in studying the superconducting state

  6. International Journal of Rock Mechanics & Mining Sciences 45 (2008) 12111225 Consolidation settlements above deep tunnels in fractured

    E-Print Network [OSTI]

    2008-01-01T23:59:59.000Z

    and pore-pressure changes around the tunnel. This is a concern for the 57 km long Gotthard Base Tunnel several important concrete dams. Thus, the assessment and prediction of potential surface displacements, the explicit inclusion of geological structures in the distinct-element models enabled a better fit

  7. A Novel Si-Tunnel FET based SRAM Design for Ultra Low-Power 0.3V VDD Applications

    E-Print Network [OSTI]

    Yener, Aylin

    A Novel Si-Tunnel FET based SRAM Design for Ultra Low-Power 0.3V VDD Applications J. Singh, K-Band Tunnel Field Effect Transistors (TFETs) in SRAMs at ultra low supply voltages. The uni design using Si- TFETs for reliable operation with low leakage at ultra low voltages. We also demonstrate

  8. Far-infrared laser vibration-rotation-tunneling spectroscopy of the propane-water compkx: Torsional dynamics of the hydrogen

    E-Print Network [OSTI]

    Cohen, Ronald C.

    Far-infrared laser vibration-rotation-tunneling spectroscopy of the propane-water compkx: Torsional 1993) The far-infrared laservibration-rotation-tunneling (FIR-VRT) spectrumof the propane-water complex calculations. In the present paper and in its counterpart,13we present our results for the water-propane

  9. Role of midgap states in the inelastic tunneling between a d-wave superconductor and a normal metal

    E-Print Network [OSTI]

    Wei,Hongduo

    2002-01-01T23:59:59.000Z

    IT mediated by the phonons in the barrier or of the electrodes at the barrier. Unlike in N-N tunneling, where the excitable mode frequencies are revealed in d² I/d²V, here dI/dV is already sufficient to reveal the same. Comparing with N-S (s-wave) tunneling...

  10. Oxidized GaN(0001) Surfaces studied by Scanning Tunneling Microscopy and Spectroscopy and by First-Principles Theory

    E-Print Network [OSTI]

    Feenstra, Randall

    1 Oxidized GaN(0001) Surfaces studied by Scanning Tunneling Microscopy and Spectroscopy Abstract Oxidized Ga-polar GaN surfaces have been studied both experimentally and theoretically. For in tunneling spectroscopy revealed a surface band gap with size close to that of GaN, indicating that any

  11. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Overcoming tunnel vision: Redirecting the U.S. high-level nuclear waste program

    E-Print Network [OSTI]

    Kammen, Daniel M.

    permission. Overcoming tunnel vision: Redirecting the U.S. high-level nuclear waste program James Flynn

  12. A micrometer-size movable light emitting area in a resonant tunneling light emitting diode

    SciTech Connect (OSTI)

    Pettinari, G., E-mail: giorgio.pettinari@cnr.it [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); National Research Council (CNR), Institute for Photonics and Nanotechnologies (IFN-CNR), Via Cineto Romano 42, 00156 Roma (Italy); Balakrishnan, N.; Makarovsky, O.; Campion, R. P.; Patanè, A. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)] [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Polimeni, A.; Capizzi, M. [CNISM-Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma (Italy)] [CNISM-Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma (Italy)

    2013-12-09T23:59:59.000Z

    We report on the fabrication of a micrometer-size movable light emitting area in a GaAs/AlAs quantum well resonant tunneling p-i-n diode. The spatial position of the micrometer-size light emitting area shifts linearly with increasing applied bias, up to 30??m for a bias increment of 0.2?V. Also, the simultaneous resonant tunneling injection of both electrons and holes into the quantum well states is achieved at specific positions of the diode, thus resulting in a tenfold increase of the electroluminescence intensity.

  13. Reduced low frequency noise in electron beam evaporated MgO magnetic tunnel junctions

    SciTech Connect (OSTI)

    Diao, Z.; Feng, J. F.; Kurt, H.; Feng, G.; Coey, J. M. D. [CRANN and School of Physics, Trinity College, Dublin 2 (Ireland)

    2010-05-17T23:59:59.000Z

    We compare low frequency noise in magnetic tunnel junctions with MgO barriers prepared by electron-beam evaporation with those prepared by radiofrequency sputtering, both showing a high tunneling magnetoresistance. The normalized noise parameter in the parallel state of junctions with evaporated barriers is at least one order of magnitude lower than that in junctions with sputtered barriers, and exhibits a weaker bias dependence. The lowest normalized noise is in the 10{sup -11} mum{sup 2} range. A lower density of oxygen vacancies acting as charge trap states in the evaporated MgO is responsible for the lower noise.

  14. Tunneling characteristics in chemical vapor deposited graphene–hexagonal boron nitride–graphene junctions

    SciTech Connect (OSTI)

    Roy, T.; Hesabi, Z. R.; Joiner, C. A.; Vogel, E. M. [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, Georgia 30332 (United States); Liu, L.; Gu, G. [Department of Electrical Engineering and Computer Science, University of Tennessee, 1520 Middle Drive, Knoxville, Tennessee 37996 (United States); Barrera, S. de la; Feenstra, R. M. [Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213 (United States); Chakrabarti, B. [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, Georgia 30332 (United States); Department of Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Rd., Richardson, Texas 75080 (United States)

    2014-03-24T23:59:59.000Z

    Large area chemical vapor deposited graphene and hexagonal boron nitride was used to fabricate graphene–hexagonal boron nitride–graphene symmetric field effect transistors. Gate control of the tunneling characteristics is observed similar to previously reported results for exfoliated graphene–hexagonal boron nitride–graphene devices. Density-of-states features are observed in the tunneling characteristics of the devices, although without large resonant peaks that would arise from lateral momentum conservation. The lack of distinct resonant behavior is attributed to disorder in the devices, and a possible source of the disorder is discussed.

  15. Note: Long-range scanning tunneling microscope for the study of nanostructures on insulating substrates

    SciTech Connect (OSTI)

    Molina-Mendoza, Aday J., E-mail: aday.molina@uam.es [Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid (Spain); Rodrigo, José G.; Rubio-Bollinger, Gabino [Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid (Spain); Condensed Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia de Materiales “Nicolás Cabrera,” Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid (Spain); Island, Joshua; Burzuri, Enrique; Zant, Herre S. J. van der [Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft (Netherlands); Agraït, Nicolás [Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid (Spain) [Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid (Spain); Condensed Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia de Materiales “Nicolás Cabrera,” Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid (Spain); Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid (Spain)

    2014-02-15T23:59:59.000Z

    The scanning tunneling microscope (STM) is a powerful tool for studying the electronic properties at the atomic level, however, it is of relatively small scanning range and the fact that it can only operate on conducting samples prevents its application to study heterogeneous samples consisting of conducting and insulating regions. Here we present a long-range scanning tunneling microscope capable of detecting conducting micro and nanostructures on insulating substrates using a technique based on the capacitance between the tip and the sample and performing STM studies.

  16. Using tevatron magnets for HE-LHC or new ring in LHC tunnel

    SciTech Connect (OSTI)

    Piekarz, Henryk; /Fermilab

    2011-08-01T23:59:59.000Z

    Two injector accelerator options for HE-LHC of p{sup +} - p{sup +} collisions at 33 TeV cms energy are briefly outlined. One option is based on the Super-SPS (S-SPS) accelerator in the SPS tunnel, and the other one is based on the LER (Low-Energy-Ring) accelerator in the LHC tunnel. Expectations of performance of the main arc accelerator magnets considered for the construction of the S-SPS and of the LER accelerators are used to tentatively devise some selected properties of these accelerators as potential injectors to HE-LHC.

  17. Local tunneling characteristics near a grain boundary of a d-wave superconductor as probed by a normal-metal or a low-Tc-superconductor STM tip

    E-Print Network [OSTI]

    Zhao, Hongwei

    2005-08-29T23:59:59.000Z

    We studied the local single-particle tunneling characteristics [as observed with scanning tunnel microscopy (STM)] for N D and S D tunneling, where N is a normal metal, S is a s-wave superconductor, and D is a d-wave superconductor with a {100...

  18. Novel Contrast Mechanism in Cross-Sectional Scanning Tunneling Microscopy of GaSb/GaAs Type-II Nanostructures

    E-Print Network [OSTI]

    Feenstra, Randall

    very interesting both for fundamental physics23 and applications as e.g. charge storage devices24-II Nanostructures R. Timm,1, R. M. Feenstra,2 H. Eisele,1 A. Lenz,1 L. Ivanova,1 E. Lenz,3 and M. D¨ahne1 1, sharply defined contrast of the nanostructure at negative sample bias, but a smoothly broadened contrast

  19. Types of Reuse

    Broader source: Energy.gov [DOE]

    The following provides greater detail regarding the types of reuse pursued for LM sites. It should be noted that many actual reuses combine several types of the uses listed below.

  20. InGaAs tunnel diodes for the calibration of semi-classical and quantum mechanical band-to-band tunneling models

    SciTech Connect (OSTI)

    Smets, Quentin; Verreck, Devin; Vandervorst, Wilfried; Groeseneken, Guido; Heyns, Marc M. [Imec, Kapeldreef 75, 3001 Heverlee (Belgium); KULeuven, 3001 Leuven (Belgium); Verhulst, Anne S.; Rooyackers, Rita; Merckling, Clément; Simoen, Eddy; Collaert, Nadine; Thean, Voon Y. [Imec, Kapeldreef 75, 3001 Heverlee (Belgium); Van De Put, Maarten; Sorée, Bart [Imec, Kapeldreef 75, 3001 Heverlee (Belgium); Universiteit Antwerpen, 2020 Antwerpen (Belgium)

    2014-05-14T23:59:59.000Z

    Promising predictions are made for III-V tunnel-field-effect transistor (FET), but there is still uncertainty on the parameters used in the band-to-band tunneling models. Therefore, two simulators are calibrated in this paper; the first one uses a semi-classical tunneling model based on Kane's formalism, and the second one is a quantum mechanical simulator implemented with an envelope function formalism. The calibration is done for In{sub 0.53}Ga{sub 0.47}As using several p+/intrinsic/n+ diodes with different intrinsic region thicknesses. The dopant profile is determined by SIMS and capacitance-voltage measurements. Error bars are used based on statistical and systematic uncertainties in the measurement techniques. The obtained parameters are in close agreement with theoretically predicted values and validate the semi-classical and quantum mechanical models. Finally, the models are applied to predict the input characteristics of In{sub 0.53}Ga{sub 0.47}As n- and p-lineTFET, with the n-lineTFET showing competitive performance compared to MOSFET.

  1. Surface plasmon beam splitting by the photon tunneling through the plasmonic nanogap

    E-Print Network [OSTI]

    Park, Namkyoo

    Surface plasmon beam splitting by the photon tunneling through the plasmonic nanogap Seung-Yeol Lee Center for Active Plasmonics Application Systems, Inter-University Semiconductor Research Center, School that splits a surface plasmon beam by using double triangular prisms coated on a metal surface is proposed

  2. Modelling a Car Safety Controller in Road Tunnels using Hybrid Petri Nets A. Bobbio[1

    E-Print Network [OSTI]

    Horváth, András

    Modelling a Car Safety Controller in Road Tunnels using Hybrid Petri Nets A. Bobbio[1] , M this specific issue and proposes a hybrid modeling approach based on fluid Petri nets (FPN). An FPN is used that FPN is a valid paradigm to model the dynamics of a car in a detailed way. 1 Introduction In the last

  3. Seismic modeling and analysis of a prototype heated nuclear waste storage tunnel, Yucca Mountain, Nevada

    E-Print Network [OSTI]

    Snieder, Roel

    Seismic modeling and analysis of a prototype heated nuclear waste storage tunnel, Yucca Mountain was heated to replicate the effects of long-term storage of decaying nuclear waste and to study the effects for the long- term storage of high-level nuclear waste from reactors and decom- missioned atomic weapons

  4. Integrated Geophysical Examination of the CRREL Permafrost Tunnel's Fairbanks Silt Units, Fox, Alaska

    E-Print Network [OSTI]

    Stillman, David E.

    C41A-0429 Integrated Geophysical Examination of the CRREL Permafrost Tunnel's Fairbanks Silt Units report on a recent geophysical survey of the U.S. Army Corps of Engineers' Cold Region Research geophysical signatures of permanently frozen loess and massive wedge ice. We exploited the increasing path

  5. Measurement of the Equivalent Thermal Resistance of Rooftop Lawns in a Hot-Climate Wind Tunnel

    E-Print Network [OSTI]

    Meng, Q.; Zhang, Y.; Zhang, L.

    2006-01-01T23:59:59.000Z

    rooftop lawn. A hot-climate wind tunnel experiment was carried out in order to obtain and analyze the heat and moisture transport in the rooftop lawn. Furthermore, a calculation with the energy conservation equation was carried out using the results...

  6. Decay of the cosmological constant: Equivalence of quantum tunneling and thermal activation in two spacetime dimensions

    SciTech Connect (OSTI)

    Gomberoff, Andres; Henneaux, Marc; Teitelboim, Claudio [Centro de Estudios Cientificos (CECS), Valdivia (Chile); Physique Theorique et Mathematique, Universite Libre de Bruxelles and International Solvay Institutes, ULB Campus Plaine C.P. 231, B-1050 Brussels (Belgium); Centro de Estudios Cientificos (CECS), Valdivia (Chile); Centro de Estudios Cientificos (CECS), Valdivia (Chile)

    2005-03-15T23:59:59.000Z

    We study the decay of the cosmological constant in two spacetime dimensions through production of pairs. We show that the same nucleation process looks as quantum-mechanical tunneling (instanton) to one Killing observer and as thermal activation (thermalon) to another. Thus, we find another striking example of the deep interplay between gravity, thermodynamics and quantum mechanics which becomes apparent in presence of horizons.

  7. Benchmark of aerodynamic cycling helmets using a refined wind tunnel test protocol for helmet drag research

    E-Print Network [OSTI]

    Sidelko, Stephanie

    2007-01-01T23:59:59.000Z

    The study of aerodynamics is very important in the world of cycling. Wind tunnel research is conducted on most of the equipment that is used by a rider and is a critical factor in the advancement of the sport. However, to ...

  8. Wurtzite GaN Surface Structures Studied by Scanning Tunneling Microscopy and Reflection High Energy

    E-Print Network [OSTI]

    Feenstra, Randall

    Wurtzite GaN Surface Structures Studied by Scanning Tunneling Microscopy and Reflection High Energy studies of the surface reconstructions for both the Ga-face and the N-face of wurtzite GaN films grown a surface phenomenon. Although numerous surface studies of wurtzite GaN have been performed, progress

  9. Speech Enhancement of Noisy Speech Using Log-Spectral Amplitude Estimator and Harmonic Tunneling

    E-Print Network [OSTI]

    Wichmann, Felix

    Speech Enhancement of Noisy Speech Using Log-Spectral Amplitude Estimator and Harmonic Tunneling we present a two stage noise reduction algo- rithm for speech enhancement. The speech noise removal and decreases the performance of speech coding and speech recog- nition systems. In speech enhancement

  10. SCANNING TUNNELING MICROSCOPE Operating Instructions On How To Get Atomic Resolution Images

    E-Print Network [OSTI]

    SCANNING TUNNELING MICROSCOPE Operating Instructions On How To Get Atomic Resolution Images Do: STM Set-Up: Use either a scanning tip from the tip wire box (skip to the "While holding the tip wire a 45-degree cut on one end of the tip wire, which becomes the scanning tip. Hold the tip wire

  11. Simultaneous topographic and elemental chemical and magnetic contrast in scanning tunneling microscopy

    DOE Patents [OSTI]

    Rose, Volker; Preissner, Curt A; Hla, Saw-Wai; Wang, Kangkang; Rosenmann, Daniel

    2014-09-30T23:59:59.000Z

    A method and system for performing simultaneous topographic and elemental chemical and magnetic contrast analysis in a scanning, tunneling microscope. The method and system also includes nanofabricated coaxial multilayer tips with a nanoscale conducting apex and a programmable in-situ nanomanipulator to fabricate these tips and also to rotate tips controllably.

  12. CMOS Interface Circuits for Spin Tunneling Junction Based Magnetic Random Access Memories

    SciTech Connect (OSTI)

    Ganesh Saripalli

    2002-12-31T23:59:59.000Z

    Magneto resistive memories (MRAM) are non-volatile memories which use magnetic instead of electrical structures to store data. These memories, apart from being non-volatile, offer a possibility to achieve densities better than DRAMs and speeds faster than SRAMs. MRAMs could potentially replace all computer memory RAM technologies in use today, leading to future applications like instan-on computers and longer battery life for pervasive devices. Such rapid development was made possible due to the recent discovery of large magnetoresistance in Spin tunneling junction devices. Spin tunneling junctions (STJ) are composite structures consisting of a thin insulating layer sandwiched between two magnetic layers. This thesis research is targeted towards these spin tunneling junction based Magnetic memories. In any memory, some kind of an interface circuit is needed to read the logic states. In this thesis, four such circuits are proposed and designed for Magnetic memories (MRAM). These circuits interface to the Spin tunneling junctions and act as sense amplifiers to read their magnetic states. The physical structure and functional characteristics of these circuits are discussed in this thesis. Mismatch effects on the circuits and proper design techniques are also presented. To demonstrate the functionality of these interface structures, test circuits were designed and fabricated in TSMC 0.35{micro} CMOS process. Also circuits to characterize the process mismatches were fabricated and tested. These results were then used in Matlab programs to aid in design process and to predict interface circuit's yields.

  13. Observation of spin-dependent quantum well resonant tunneling in textured CoFeB layers

    SciTech Connect (OSTI)

    Teixeira, J. M., E-mail: jmteixeira@fc.up.pt; Costa, J. D.; Ventura, J.; Sousa, J. B. [IFIMUP and IN-Institute of Nanoscience and Nanotechnology, and Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Wisniowski, P. [Department of Electronics, AGH University of Science and Technology, 30-059 Krakow (Poland); Freitas, P. P. [INESC-MN and IN-Institute of Nanoscience and Nanotechnology, Rua Alves Redol, 9-1, 1000-029 Lisbon (Portugal)

    2014-03-17T23:59:59.000Z

    We report the observation of spin-dependent quantum well (QW) resonant tunneling in textured CoFeB free layers of single MgO magnetic tunnel junctions (MTJs). The inelastic electron tunneling spectroscopy spectra clearly show the presence of resonant oscillations in the parallel configuration, which are related with the appearance of majority-spin ?{sub 1} QW states in the CoFeB free layer. To gain a quantitative understanding, we calculated QW state positions in the voltage-thickness plane using the so-called phase accumulation model (PAM) and compared the PAM solutions with the experimental resonant voltages observed for a set of MTJs with different CoFeB free layer thicknesses (t{sub fl}?=?1.55, 1.65, 1.95, and 3.0?nm). An overall good agreement between experiment and theory was obtained. An enhancement of the tunnel magnetoresistance with bias is observed in a bias voltage region corresponding to the resonant oscillations.

  14. Close-in blasting at the TRI-MET light rail tunnels in Portland, Oregon

    SciTech Connect (OSTI)

    Revey, G.F.; Painter, D.Z.

    1995-12-31T23:59:59.000Z

    Frontier/Traylor Joint Venture is presently constructing a section of the Tri-County Metropolitan Transit District of Oregon`s (TRI-MET) Westside Light Rail System. This new section will extend Portland`s existing transit system to the western suburbs of Beaverton and Hillsboro. The drill-blast excavations at this project include 10,000 feet of 20 foot tunnel, 18 cross passages, three shafts, an underground railway station, and a U-wall open cut. From a blast designer`s perspective, this job has been extremely challenging. Blast vibration is limited to 0.5 ips at 200 feet or at the nearest structure, and airblast is limited to 129 dB--linear peak and 96 dB--C scale. The tunnels pass under heavily built up areas and have top of tunnel to surface cover distances as low as 70 feet. Surface blasting in the 26,000 cubic yard U-wall excavation was limited to five short nighttime periods due to its proximity to the very busy highway 26. This paper describes the techniques that were used to develop safe blasting designs for the TRI-MET Surface blasts and tunnel rounds. It also discusses the measures that were necessary to mitigate noise, vibration, and flyrock.

  15. advanced wind-tunnel instrumentation: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    advanced wind-tunnel instrumentation First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 REVIEW OF...

  16. Crossover from tunneling to meta.llic behavior in superconductofgsemiconductor contacts

    E-Print Network [OSTI]

    Woodall, Jerry M.

    -dominated transport at the superconductor-semiconductor contacts as Schottky barrier thickness decreases of such a crossover in a thin-film structure, and are of interest for investigations of hybrid superconductor-semiconductorCrossover from tunneling to meta.llic behavior in superconductofgsemiconductor contacts A. W

  17. Controlled Low-Temperature Molecular Manipulation of Sexiphenyl Molecules on Ag(111) Using Scanning Tunneling Microscopy

    E-Print Network [OSTI]

    Hla, Saw-Wai

    Controlled Low-Temperature Molecular Manipulation of Sexiphenyl Molecules on Ag(111) Using Scanning; published 11 November 2004) A novel scanning tunneling microscope manipulation scheme for a controlled displaced during imag- ing and often dragged with the STM tip [17]. Atomically controlled manipulation

  18. Natural Ventilation in Buildings: Measurement in a Wind Tunnel and Numerical Simulation with Large Eddy Simulation

    E-Print Network [OSTI]

    Chen, Qingyan "Yan"

    save energy consumed by the heating, ventilating, and air- conditioning systems in a building1 Natural Ventilation in Buildings: Measurement in a Wind Tunnel and Numerical Simulation@purdue.edu Abstract Natural ventilation in buildings can create a comfortable and healthy indoor environment, and can

  19. Thoughts on entropic gravity in the Parikh-Wilczek tunneling model of Hawking radiation

    E-Print Network [OSTI]

    Wen-Yu Wen

    2014-05-28T23:59:59.000Z

    In this letter, we use the Parikh-Wilczek tunneling model of Hawking radiation to illustrate that a reformulation of Verlinde's entropic gravity is needed to derive the Newton's law for a temperature-varying screen, demanded by the conservation of energy. Furthermore, the entropy stored in the holographic screen is shown to be additive and its temperature dependence can be obtained.

  20. CALCULATIONS OF FIRE SMOKE BEHAVIOUR IN LONG RAIL TUNNELS S. DARON, E. RUFFIN

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    2000-13 CALCULATIONS OF FIRE SMOKE BEHAVIOUR IN LONG RAIL TUNNELS S. DAÃ?RON, E. RUFFIN INERIS Parc in complex underground networks, we want to implement a coupling between a ID ventilation code and a CFD model or a zone model. The project consists in 3 main steps: the development of a ID ventilation code

  1. Tunneling between the giant gravitons in AdS5 x S5

    E-Print Network [OSTI]

    Julian Lee

    2001-04-05T23:59:59.000Z

    I consider the giant gravitons in AdS5 x S5. By numerical simulation, I show a strong indication that there is no instanton solution describing the direct tunneling between the giant graviton in the S5 and its dual counterpart in the AdS5. I argue that it supports the supersymmetry breaking scenario suggested in hep-th/0008015

  2. Measurement of the Equivalent Thermal Resistance of Rooftop Lawns in a Hot-Climate Wind Tunnel 

    E-Print Network [OSTI]

    Meng, Q.; Zhang, Y.; Zhang, L.

    2006-01-01T23:59:59.000Z

    rooftop lawn. A hot-climate wind tunnel experiment was carried out in order to obtain and analyze the heat and moisture transport in the rooftop lawn. Furthermore, a calculation with the energy conservation equation was carried out using the results...

  3. KS-UWT Building Plans 12 July 2006 TAMU Wind Tunnel Complex

    E-Print Network [OSTI]

    -scale boundary-layer measurements which are not feasible in larger tunnels · Originally from NASA-Glenn Research-turbulence, closed-return facility that can generate oscillatory flows · Maximum speed- 35 m/s, 1.4 x 1.4 x 4.9 m

  4. Spontaneous emission from a two--level atom tunneling in a double--well potential

    E-Print Network [OSTI]

    Daniel Braun; John Martin

    2007-10-26T23:59:59.000Z

    We study a two-level atom in a double--well potential coupled to a continuum of electromagnetic modes (black body radiation in three dimensions at zero absolute temperature). Internal and external degrees of the atom couple due to recoil during emission of a photon. We provide a full analysis of the problem in the long wavelengths limit up to the border of the Lamb-Dicke regime, including a study of the internal dynamics of the atom (spontaneous emission), the tunneling motion, and the electric field of the emitted photon. The tunneling process itself may or may not decohere depending on the wavelength corresponding to the internal transition compared to the distance between the two wells of the external potential, as well as on the spontaneous emission rate compared to the tunneling frequency. Interference fringes appear in the emitted light from a tunneling atom, or an atom in a stationary coherent superposition of its center--of--mass motion, if the wavelength is comparable to the well separation, but only if the external state of the atom is post-selected.

  5. Effect of the hydrogen tunnelling states of the acoustic wave propagation in niobium at low temperatures

    E-Print Network [OSTI]

    Boyer, Edmond

    L-387 Effect of the hydrogen tunnelling states of the acoustic wave propagation in niobium at low son à 200 MHz a été mesurée jusqu'à 50 mK dans des monocristaux de niobium contenant de l'oxygène et at 200 MHz has been measured down to 50 mK in single crystals of niobium doped with oxygen and hydrogen

  6. Wind-Tunnel Simulation of Pedestrian-Level Wind in Los Angeles Bruce R. White

    E-Print Network [OSTI]

    White, Bruce

    Wind-Tunnel Simulation of Pedestrian-Level Wind in Los Angeles Bruce R. White University-level winds within the South Coast Air Basin, a 6,000-square mile area that includes Orange County, most of Los Angeles and Riverside Counties. Working with the city of Los Angeles officials guidelines for wind

  7. Multi-field open inflation model and multi-field dynamics in tunneling

    SciTech Connect (OSTI)

    Sugimura, Kazuyuki; Yamauchi, Daisuke; Sasaki, Misao, E-mail: sugimura@yukawa.kyoto-u.ac.jp, E-mail: yamauchi@icrr.u-tokyo.ac.jp, E-mail: misao@yukawa.kyoto-u.ac.jp [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto (Japan)

    2012-01-01T23:59:59.000Z

    We consider a multi-field open inflation model, in which one of the fields dominates quantum tunneling from a false vacuum while the other field governs slow-roll inflation within the bubble nucleated from false vacuum decay. We call the former the tunneling field and the latter the inflaton field. In the limit of a negligible interaction between the two fields, the false vacuum decay is described by a Coleman-De Luccia instanton. Here we take into account the coupling between the two fields and construct explicitly a multi-field instanton for a simple quartic potential model. We also solve the evolution of the scalar fields within the bubble. We find our model realizes open inflation successfully. This is the first concrete, viable model of open inflation realized with a simple potential. We then study the effect of the multi-field dynamics on the false vacuum decay, specifically on the tunneling rate. We find the tunneling rate increases in general provided that the multi-field effect can be treated perturbatively.

  8. Resonant tunneling and the bimodal symmetric fission of sup 258 Fm

    SciTech Connect (OSTI)

    Bhandari, B.S. (Department of Physics, Faculty of Science, University of Garyounis, Benghazi, Libya (LY))

    1991-02-25T23:59:59.000Z

    The concept of resonant tunneling is invoked to explain the sharp drop in the measured spontaneous-fission half-life when going from {sup 256}Fm to {sup 258}Fm. Various consequences of such a suggestion on the other observed characteristics of the bimodal symmetric fission of {sup 258}Fm are briefly discussed.

  9. Systematic Approach for Computing Zero-Point Energy, Quantum Partition Function, and Tunneling Effect Based

    E-Print Network [OSTI]

    Minnesota, University of

    Systematic Approach for Computing Zero-Point Energy, Quantum Partition Function, and Tunneling, and a proton-transfer barrier modeled by the Eckart potential. The zero-point energy, quantum partition agreement with the ground-state energy (zero-point energy), and the position of the centroid potential

  10. Angular domain optical imaging of turbid media using enhanced micro-tunnel filter arrays

    E-Print Network [OSTI]

    Chapman, Glenn H.

    performed in tissue mimicking phantoms using a 2-cm thick optical cell with 0.25% IntralipidTM and a near infrared laser. This paper also presents experimental results of the angular domain imaging system employing novel micro-tunnel arrays with minimal internal reflection which can accept the non- scattered

  11. Selective Analysis of Molecular States by Functionalized Scanning Tunneling Microscopy Tips Z. T. Deng,1

    E-Print Network [OSTI]

    Gao, Hongjun

    . Deng,1 H. Lin,2 W. Ji,1 L. Gao,1 X. Lin,1 Z. H. Cheng,1 X. B. He,1 J. L. Lu,1 D. X. Shi,1 W. A. Hofer,2Selective Analysis of Molecular States by Functionalized Scanning Tunneling Microscopy Tips Z. T

  12. Tunneling characteristics in chemical vapor deposited graphene hexagonal boron nitride graphene junctions

    E-Print Network [OSTI]

    Feenstra, Randall

    1 Tunneling characteristics in chemical vapor deposited graphene ­ hexagonal boron nitride ­ graphene junctions T. Roy1 , L. Liu2 , S. de la Barrera,3 B. Chakrabarti1,4 , Z. R. Hesabi1 , C. A. Joiner1 Abstract: Large area chemical vapor deposited graphene and hexagonal boron nitride was used to fabricate

  13. Quantum corrected non-thermal radiation spectrum from the tunnelling mechanism

    E-Print Network [OSTI]

    Subenoy Chakraborty; Subhajit Saha; Christian Corda

    2015-05-28T23:59:59.000Z

    Tunnelling mechanism is today considered a popular and widely used method in describing Hawking radiation. However, in relation to black hole (BH) emission, this mechanism is mostly used to obtain the Hawking temperature by comparing the probability of emission of an outgoing particle with the Boltzmann factor. On the other hand, Banerjee and Majhi reformulated the tunnelling framework deriving a black body spectrum through the density matrix for the outgoing modes for both the Bose-Einstein distribution and the Fermi-Dirac distribution. In contrast, Parikh and Wilczek introduced a correction term performing an exact calculation of the action for a tunnelling spherically symmetric particle and, as a result, the probability of emission of an outgoing particle corresponds to a non-strictly thermal radiation spectrum. Recently, one of us (C. Corda) introduced a BH effective state and was able to obtain a non-strictly black body spectrum from the tunnelling mechanism corresponding to the probability of emission of an outgoing particle found by Parikh and Wilczek. The present work introduces the quantum corrected effective temperature and the corresponding quantum corrected effective metric is written using Hawking's periodicity arguments. Thus, we obtain further corrections to the non-strictly thermal BH radiation spectrum as the final distributions take into account both the BH dynamical geometry during the emission of the particle and the quantum corrections to the semiclassical Hawking temperature.

  14. Current Collapse in Tunneling Transport through Benzene M. H. Hettler,1

    E-Print Network [OSTI]

    Current Collapse in Tunneling Transport through Benzene M. H. Hettler,1 W. Wenzel,1 M. R. Wegewijs; published 20 February 2003) We investigate the electrical transport through a system of benzene coupled model for the electrons of the benzene is derived that includes general two-body interactions. After

  15. The benzene molecule as a molecular resonant-tunneling transistor M. Di Ventraa)

    E-Print Network [OSTI]

    Pantelides, Sokrates T.

    The benzene molecule as a molecular resonant-tunneling transistor M. Di Ventraa) and S. T of transport through a benzene-1, 4-dithiolate molecule with a third capacitive terminal gate . We find rectification was demonstrated in 1993.2 More recently, Reed et al. investigated the benzene-1, 4-dithiol rings

  16. Giant higher harmonic generation in mesoscopic metal wires and rings interrupted by tunnel junctions

    E-Print Network [OSTI]

    van Oudenaarden, Alexander

    Giant higher harmonic generation in mesoscopic metal wires and rings interrupted by tunnel 5046, 2600 GA Delft, The Netherlands Received 19 December 1997 Higher harmonic generation in mesoscopic is biased with a sinusoidal varying current, we observe giant higher harmon- ics in the conductance

  17. Cross-sectional Scanning Tunneling Microscopy and Spectroscopy of InGaP/GaAs Heterojunctions

    E-Print Network [OSTI]

    Feenstra, Randall

    1 Cross-sectional Scanning Tunneling Microscopy and Spectroscopy of InGaP/GaAs Heterojunctions Y Abstract Compositionally abrupt InGaP/GaAs heterojunctions grown by gas-source molecular beam epitaxy have the InGaP layer show non-uniform In and Ga distribution. About 1.5 nm of transition region

  18. Semiconductor lasers with broad tunnel-coupled waveguides, emitting at a wavelength of 980 nm

    SciTech Connect (OSTI)

    Zvonkov, N B; Ershov, A V; Zvonkov, B N; Maksimov, G A; Uskova, E A [Scientific-Research Physicotechnical Institute at the Nizhnii Novgorod State University, Nizhnii Novgorod (Russian Federation); Akhlestina, S A [Research Insitute of Chemistry, N.I. Lobachevskii Nizhnii Novgorod State University, Nizhnii Novgorod (Russian Federation)

    1999-03-31T23:59:59.000Z

    InGaP/GaAs/InGaAs semiconductor lasers with broad tunnel-coupled waveguides were developed and investigated experimentally. Output radiation power of 5.2 - 5.8 W was obtained from an emitting region 100 {mu}m wide with a 36{sup 0} divergence of the emitted radiation in a plane perpendicular to the p - n junction. (lasers)

  19. WIND-TUNNEL STUDY ON AERODYNAMIC PERFORMANCE OF SMALL VERTICAL-AXIS WIND TURBINES

    E-Print Network [OSTI]

    Leu, Tzong-Shyng "Jeremy"

    1 WIND-TUNNEL STUDY ON AERODYNAMIC PERFORMANCE OF SMALL VERTICAL-AXIS WIND TURBINES J. J. Miau*1 were carried out to study the aerodynamic performance of three vertical axis wind turbines (VAWTs. On the other hand, the characteristics of unsteady flow around the helical wind turbine were studied with a hot

  20. Molecular engineering of oligomerization and metabolite channeling through a molecular tunnel of carbamoyl phosphate synthetase

    E-Print Network [OSTI]

    Kim, Jungwook

    2004-09-30T23:59:59.000Z

    -23, and Gly-575 from the large subunit of CPS were substituted by mutagenesis with bulkier amino acids in an attempt to obstruct and/or hinder the passage of the unstable intermediate through the carbamate tunnel. The kinetic data are consistent...

  1. GROUND MOVEMENTS DUE TO SHALLOW TUNNELS IN SOFT GROUND: 1. ANALYTICAL SOLUTIONS

    E-Print Network [OSTI]

    Entekhabi, Dara

    use of numerical analyses, particularly non-linear finite element methods, over a period of more than. Deformation fields based on the superposition of fundamental, singularity solutions are shown to differ only of very shallow tunnels. The Authors demonstrate a simplified method to account for soil plasticity

  2. Policy Name: Golf Carts in Tunnels Originating/Responsible Department: Facilities Management and Planning

    E-Print Network [OSTI]

    Carleton University

    to their manager or department head all incidents involving injury to persons or damage to property. ReportingPolicy Name: Golf Carts in Tunnels Originating/Responsible Department: Facilities Management and Planning Approval Authority: Senior Management Committee Date of Original Policy: October 2008 Last Updated

  3. Magnetic tunnel junctions for magnetic field sensor by using CoFeB sensing layer capped with MgO film

    SciTech Connect (OSTI)

    Takenaga, Takashi, E-mail: takenaga@leap.or.jp; Tsuzaki, Yosuke; Yoshida, Chikako; Yamazaki, Yuichi; Hatada, Akiyoshi; Nakabayashi, Masaaki; Iba, Yoshihisa; Takahashi, Atsushi; Noshiro, Hideyuki; Tsunoda, Koji; Aoki, Masaki; Furukawa, Taisuke; Fukumoto, Hiroshi; Sugii, Toshihiro [Low-power Electronics Association and Project (LEAP), Tsukuba 305-8569 (Japan)

    2014-05-07T23:59:59.000Z

    We evaluated MgO-based magnetic tunnel junctions (MTJs) for magnetic field sensors with spin-valve-type structures in the CoFeB sensing layer capped by an MgO film in order to obtain both top and bottom interfaces of MgO/CoFeB exhibiting interfacial perpendicular magnetic anisotropy (PMA). Hysteresis of the CoFeB sensing layer in these MTJs annealed at 275?°C was suppressed at a thickness of the sensing layer below 1.2?nm by interfacial PMA. We confirmed that the CoFeB sensing layers capped with MgO suppress the thickness dependences of both the magnetoresistance ratio and the magnetic behaviors of the CoFeB sensing layer more than that of the MTJ with a Ta capping layer. MgO-based MTJs with MgO capping layers can improve the controllability of the characteristics for magnetic field sensors.

  4. Property:Channel/Tunnel/Flume | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to: navigation,PillarPublicationType Jump to: navigation, search This isCapRockAgeChallenges

  5. Typed Self-Optimization

    E-Print Network [OSTI]

    Brown, Matt

    2013-01-01T23:59:59.000Z

    type T y[O]. The operator IsIs is self-applicative, in thatargument t is any of Is[O] or IsIs, and otherwise behavesproof constant introduced by IsIs proves that the type of t

  6. Silicon field-effect transistor based on quantum tunneling J. FL Tucker, Chinlee Wang, and P. Scott Carney

    E-Print Network [OSTI]

    Bhargava, Rohit

    configuration, the gate could be offset in order to permit a shallow implant of the finished device to convert a commercial package, SEMICAD,' together with our own cal- culation of tunneling and thermionic emission

  7. Earth pressure balance (EPB) shield tunneling in Bangkok : ground response and prediction of surface settlements using artificial neural networks

    E-Print Network [OSTI]

    Suwansawat, Suchatvee, 1972-

    2002-01-01T23:59:59.000Z

    Although Earth Pressure Balance (EPB) shields have been used for several decades, very little information exists about the actual mechanisms of shield-ground interaction. The ground response mechanism induced by EPB tunneling ...

  8. Prediction of net bedload transport rates obtained in oscillating water tunnels and applicability to real surf zone waves

    E-Print Network [OSTI]

    Gonzalez-Rodriguez, David

    Experimental studies of sediment transport rates due to near shore waves are often conducted in oscillating water tunnels (OWTs). In an OWT, the oscillatory motion produced by the piston propagates almost instantaneously ...

  9. Your Guide to Diabetes: Type 1 and Type 2

    E-Print Network [OSTI]

    Rau, Don C.

    Your Guide to Diabetes: Type 1 and Type 2 National Diabetes Information Clearinghouse #12;#12;Your Guide to Diabetes: Type 1 and Type 2 #12;#12;Contents Learn about Diabetes ............................................................ 1 What is diabetes? .............................................................. 2 What

  10. A Historical Evaluation of the U12t Tunnel, Nevada Test Site, Nye County, Nevada, Volume 2 of 6

    SciTech Connect (OSTI)

    Harold Drollinger; Robert C. Jones; and Thomas F. Bullard; Desert Research Institute, Laurence J. Ashbaugh, Southern Nevada Courier Service and Wayne R. Griffin, Stoller-Navarro Joint Venture

    2009-02-01T23:59:59.000Z

    This report presents a historical evaluation of the U12t Tunnel on the Nevada Test Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12t Tunnel is one of a series of tunnels used for underground nuclear weapons effects tests on the east side of Rainier and Aqueduct Mesas. Six nuclear weapons effects tests, Mint Leaf, Diamond Sculls, Husky Pup, Midas Myth/Milagro, Mighty Oak, and Mission Ghost, and one high explosive test, SPLAT, were conducted within the U12t Tunnel from 1970 to 1987. All six of the nuclear weapons effects tests and the high explosive test were sponsored by DTRA. Two conventional weapons experiments, Dipole Knight and Divine Eagle, were conducted in the tunnel portal area in 1997 and 1998. These experiments were sponsored by the Defense Special Weapons Agency. The U12t Tunnel complex is composed of the Portal and Mesa Areas and includes an underground tunnel with a main access drift and nine primary drifts, a substantial tailings pile fronting the tunnel portal, a series of discharge ponds downslope of the tailings pile, and two instrumentation trailer parks and 16 drill holes on top of Aqueduct Mesa. A total of 89 cultural features were recorded: 54 at the portal and 35 on the mesa. In the Portal Area, cultural features are mostly concrete pads and building foundations; other features include the portal, rail lines, the camel back, ventilation and cooling system components, communication equipment, and electrical equipment. On the mesa are drill holes, a few concrete pads, a loading ramp, and electrical equipment.

  11. A Historical Evaluation of the U12t Tunnel, Nevada Test Site, Nye County, Nevada, Volume 4 of 6

    SciTech Connect (OSTI)

    Harold Drollinger; Robert C. Jones; and Thomas F. Bullard; Desert Research Institute, Laurence J. Ashbaugh, Southern Nevada Courier Service and Wayne R. Griffin, Stoller-Navarro Joint Venture

    2009-02-01T23:59:59.000Z

    This report presents a historical evaluation of the U12t Tunnel on the Nevada Test Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12t Tunnel is one of a series of tunnels used for underground nuclear weapons effects tests on the east side of Rainier and Aqueduct Mesas. Six nuclear weapons effects tests, Mint Leaf, Diamond Sculls, Husky Pup, Midas Myth/Milagro, Mighty Oak, and Mission Ghost, and one high explosive test, SPLAT, were conducted within the U12t Tunnel from 1970 to 1987. All six of the nuclear weapons effects tests and the high explosive test were sponsored by DTRA. Two conventional weapons experiments, Dipole Knight and Divine Eagle, were conducted in the tunnel portal area in 1997 and 1998. These experiments were sponsored by the Defense Special Weapons Agency. The U12t Tunnel complex is composed of the Portal and Mesa Areas and includes an underground tunnel with a main access drift and nine primary drifts, a substantial tailings pile fronting the tunnel portal, a series of discharge ponds downslope of the tailings pile, and two instrumentation trailer parks and 16 drill holes on top of Aqueduct Mesa. A total of 89 cultural features were recorded: 54 at the portal and 35 on the mesa. In the Portal Area, cultural features are mostly concrete pads and building foundations; other features include the portal, rail lines, the camel back, ventilation and cooling system components, communication equipment, and electrical equipment. On the mesa are drill holes, a few concrete pads, a loading ramp, and electrical equipment.

  12. A Historical Evaluation of the U12t Tunnel, Nevada Test Site, Nye County, Nevada, Volume 1 of 6

    SciTech Connect (OSTI)

    Harold Drollinger; Robert C. Jones; and Thomas F. Bullard; Desert Research Institute, Laurence J. Ashbaugh, Southern Nevada Courier Service and Wayne R. Griffin, Stoller-Navarro Joint Venture

    2009-02-01T23:59:59.000Z

    This report presents a historical evaluation of the U12t Tunnel on the Nevada Test Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12t Tunnel is one of a series of tunnels used for underground nuclear weapons effects tests on the east side of Rainier and Aqueduct Mesas. Six nuclear weapons effects tests, Mint Leaf, Diamond Sculls, Husky Pup, Midas Myth/Milagro, Mighty Oak, and Mission Ghost, and one high explosive test, SPLAT, were conducted within the U12t Tunnel from 1970 to 1987. All six of the nuclear weapons effects tests and the high explosive test were sponsored by DTRA. Two conventional weapons experiments, Dipole Knight and Divine Eagle, were conducted in the tunnel portal area in 1997 and 1998. These experiments were sponsored by the Defense Special Weapons Agency. The U12t Tunnel complex is composed of the Portal and Mesa Areas and includes an underground tunnel with a main access drift and nine primary drifts, a substantial tailings pile fronting the tunnel portal, a series of discharge ponds downslope of the tailings pile, and two instrumentation trailer parks and 16 drill holes on top of Aqueduct Mesa. A total of 89 cultural features were recorded: 54 at the portal and 35 on the mesa. In the Portal Area, cultural features are mostly concrete pads and building foundations; other features include the portal, rail lines, the camel back, ventilation and cooling system components, communication equipment, and electrical equipment. On the mesa are drill holes, a few concrete pads, a loading ramp, and electrical equipment.

  13. A Historical Evaluation of the U12t Tunnel, Nevada Test Site, Nye County, Nevada, Volume 6 of 6

    SciTech Connect (OSTI)

    Harold Drollinger; Robert C. Jones; and Thomas F. Bullard; Desert Research Institute, Laurence J. Ashbaugh, Southern Nevada Courier Service and Wayne R. Griffin, Stoller-Navarro Joint Venture

    2009-02-01T23:59:59.000Z

    This report presents a historical evaluation of the U12t Tunnel on the Nevada Test Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12t Tunnel is one of a series of tunnels used for underground nuclear weapons effects tests on the east side of Rainier and Aqueduct Mesas. Six nuclear weapons effects tests, Mint Leaf, Diamond Sculls, Husky Pup, Midas Myth/Milagro, Mighty Oak, and Mission Ghost, and one high explosive test, SPLAT, were conducted within the U12t Tunnel from 1970 to 1987. All six of the nuclear weapons effects tests and the high explosive test were sponsored by DTRA. Two conventional weapons experiments, Dipole Knight and Divine Eagle, were conducted in the tunnel portal area in 1997 and 1998. These experiments were sponsored by the Defense Special Weapons Agency. The U12t Tunnel complex is composed of the Portal and Mesa Areas and includes an underground tunnel with a main access drift and nine primary drifts, a substantial tailings pile fronting the tunnel portal, a series of discharge ponds downslope of the tailings pile, and two instrumentation trailer parks and 16 drill holes on top of Aqueduct Mesa. A total of 89 cultural features were recorded: 54 at the portal and 35 on the mesa. In the Portal Area, cultural features are mostly concrete pads and building foundations; other features include the portal, rail lines, the camel back, ventilation and cooling system components, communication equipment, and electrical equipment. On the mesa are drill holes, a few concrete pads, a loading ramp, and electrical equipment.

  14. A Historical Evaluation of the U12t Tunnel, Nevada Test Site, Nye County, Nevada, Volume 3 of 6

    SciTech Connect (OSTI)

    Harold Drollinger; Robert C. Jones; and Thomas F. Bullard; Desert Research Institute, Laurence J. Ashbaugh, Southern Nevada Courier Service and Wayne R. Griffin, Stoller-Navarro Joint Venture

    2009-02-01T23:59:59.000Z

    This report presents a historical evaluation of the U12t Tunnel on the Nevada Test Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA). The U12t Tunnel is one of a series of tunnels used for underground nuclear weapons effects tests on the east side of Rainier and Aqueduct Mesas. Six nuclear weapons effects tests, Mint Leaf, Diamond Sculls, Husky Pup, Midas Myth/Milagro, Mighty Oak, and Mission Ghost, and one high explosive test, SPLAT, were conducted within the U12t Tunnel from 1970 to 1987. All six of the nuclear weapons effects tests and the high explosive test were sponsored by DTRA. Two conventional weapons experiments, Dipole Knight and Divine Eagle, were conducted in the tunnel portal area in 1997 and 1998. These experiments were sponsored by the Defense Special Weapons Agency. The U12t Tunnel complex is composed of the Portal and Mesa Areas and includes an underground tunnel with a main access drift and nine primary drifts, a substantial tailings pile fronting the tunnel portal, a series of discharge ponds downslope of the tailings pile, and two instrumentation trailer parks and 16 drill holes on top of Aqueduct Mesa. A total of 89 cultural features were recorded: 54 at the portal and 35 on the mesa. In the Portal Area, cultural features are mostly concrete pads and building foundations; other features include the portal, rail lines, the camel back, ventilation and cooling system components, communication equipment, and electrical equipment. On the mesa are drill holes, a few concrete pads, a loading ramp, and electrical equipment.

  15. Spin Accumulation Encoded in Electronic Noise for Mesoscopic Billiards with Finite Tunneling Rates

    E-Print Network [OSTI]

    J. G. G. S. Ramos; A. L. R. Barbosa; D. Bazeia; M. S. Hussein

    2012-04-12T23:59:59.000Z

    We study the effects of spin accumulation (inside reservoirs) on electronic transport with tunneling and reflections at the gates of a quantum dot. Within the stub model, the calculation focus on the current-current correlation function for the flux of electrons injected into the quantum dot. The linear response theory used allows to obtain the noise power in the regime of thermal crossover as a function of parameters that reveal the spin polarization at the reservoirs. The calculation is performed employing diagrammatic integration within the universal groups (ensembles of Dyson) for a non-ideal, non-equilibrium chaotic quantum dot. We show that changes in the spin distribution determines significant alteration in noise behavior at values of the tunneling rates close to zero, in the regime of strong reflection at the gates.

  16. Influence of magnetic electrodes thicknesses on the transport properties of magnetic tunnel junctions with perpendicular anisotropy

    SciTech Connect (OSTI)

    Cuchet, Léa; Rodmacq, Bernard; Auffret, Stéphane; Sousa, Ricardo C.; Dieny, Bernard [SPINTEC, UMR 8191, CEA-INAC/CNRS/UJF-Grenoble 1/Grenoble-INP, 38054 Grenoble Cedex (France)

    2014-08-04T23:59:59.000Z

    The influence of the bottom and top magnetic electrodes thicknesses on both perpendicular anisotropy and transport properties is studied in (Co/Pt)/Ta/CoFeB/MgO/FeCoB/Ta magnetic tunnel junctions. By carefully investigating the relative magnetic moment of the two electrodes as a function of their thicknesses, we identify and quantify the presence of magnetically dead layers, likely localized at the interfaces with Ta, that is, 0.33?nm for the bottom electrode and 0.60?nm for the top one. Critical thicknesses (spin-reorientation transitions) are determined as 1.60 and 1.65?nm for bottom and top electrodes, respectively. The tunnel magnetoresistance ratio reaches its maximum value, as soon as both effective (corrected from dead layer) electrode thicknesses exceed 0.6?nm.

  17. Effect of the nature of the injection tunnel current on the inhomogeneous state of a superconductor

    SciTech Connect (OSTI)

    Nevirkovets, I.P.; Rudenko, E.M.

    1984-02-01T23:59:59.000Z

    Double tunnel junctions Sn--I--Sn--I--Sn are investigated. An inhomogeneous state of the Sn film, which arises due to the appearance of a second energy gap in addition to the primary one, is obtained in the regime of a narrow quasiparticle source (the voltage on the injector V/sub g/approx. =2..delta../e). The size of the gaps, which are related to the nonuniform state, decreases in a weak magnetic field. This result is explained by the decay of the constant component of the oscillatory Josephson current and by the replacement of the Josephson tunneling current at V/sub g/ = 2..delta../e by a quasiparticle current, which increases the density of nonequilibrium quasiparticles.

  18. Motion of fluxons in distributed two-dimensional Josephson tunnel junctions

    SciTech Connect (OSTI)

    Nevirkovets, I.P.; Rudenko, E.M.

    1984-01-01T23:59:59.000Z

    A strong asymmetry is observed in the current--voltage characteristics of distributed two-dimensional Sn--I--Sn, Sn--I--Pb tunnel junctions with dimensions L>>lambda/sub J/ when an external magnetic field is applied in the plane of the junction perpendicular to the L dimension for different orientations of the field. A resistive section in the form of an almost vertical step appears in the IVC in one orientation of the field and is absent in the opposite orientation. It is shown that the appearance of the steps is related to the conditions of motion of Josephson vortices in tunnel junctions under the action of the Lorentz force in the presence of a current domain at the edge of the distributed junction.

  19. Electrical characteristics and interface structure of magnetic tunnel junctions with hafnium oxyfluoride barrier

    SciTech Connect (OSTI)

    Yu, Y.Y.; Kim, D.S.; Char, K. [Center for Strongly Correlated Materials Research and School of Physics, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2004-12-01T23:59:59.000Z

    We have studied the effects of fluorine inclusion on the electrical transport characteristics and interface structure of the hafnium oxide barrier in a magnetic tunnel junction. The tunneling magnetoresistance (TMR) and resistance-area (RA) as a function of oxidation time show that the TMR ratio of the hafnium oxyfluoride barrier is higher (8.3%) than that of the hafnium oxide barrier (5.7%) at their optimum conditions, and the oxyfluoride barrier junctions maintain a high TMR ratio even when the RA product increases by three orders of magnitude. X-ray photoelectron spectroscopy analysis shows that the fluorine atoms in the oxyfluoride barrier play an important role in the formation of a barrier with uniform composition. We believe that the initial fluoride layer is causing the subsequent oxygen diffusion to slow down, resulting in the formation of a defect-free hafnium oxide layer. These results are consistent with what we have found for aluminum oxyfluoride barriers.

  20. Bohm-Aharonov and Kondo effects on tunneling currents in a mesoscopic ring

    SciTech Connect (OSTI)

    Davidovich, M.A. [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, Caixa Postal 38071, 22452-970 Rio de Janeiro, Rio de Janeiro, (Brasil)] [Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, Caixa Postal 38071, 22452-970 Rio de Janeiro, Rio de Janeiro, (Brasil); Anda, E.V. [Instituto de Fisica, Universidade Federal Fluminense, Niteroi, RJ Brasil, Avenida Litoranea s/n, Gragoata, 24210-340 Niteroi, Rio de Janeiro, (Brasil)] [Instituto de Fisica, Universidade Federal Fluminense, Niteroi, RJ Brasil, Avenida Litoranea s/n, Gragoata, 24210-340 Niteroi, Rio de Janeiro, (Brasil); Iglesias, J.R. [Instituto de Fisica, Univerisdade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970, Porto Alegre, Rio Grande do Sul, (Brasil)] [Instituto de Fisica, Univerisdade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970, Porto Alegre, Rio Grande do Sul, (Brasil); Chiappe, G. [Departamento de Fisica, Universidad de Buenos Aires, Caixa Postal 1428-Nunez, Buenos Aires (Argentina)] [Departamento de Fisica, Universidad de Buenos Aires, Caixa Postal 1428-Nunez, Buenos Aires (Argentina)

    1997-03-01T23:59:59.000Z

    We present an analysis of the Kondo effect on the Bohm-Aharonov oscillations of the tunneling currents in a mesoscopic ring with a quantum dot inserted in one of its arms. The system is described by an Anderson-impurity tight-binding Hamiltonian where the electron-electron interaction is restricted to the dot. The currents are obtained using nonequilibrium Green functions calculated through a cumulant diagrammatic expansion in the chain approximation. It is shown that at low temperature, even with the system out of resonance, the Kondo peak provides a channel for the electron to tunnel through the dot, giving rise to the Bohm-Aharonov oscillations of the current. At high temperature these oscillations are important only if the dot level is aligned to the Fermi level, when the resonance condition is satisfied. {copyright} {ital 1997} {ital The American Physical Society}

  1. Spin-orbit torque magnetization switching of a three-terminal perpendicular magnetic tunnel junction

    SciTech Connect (OSTI)

    Cubukcu, Murat; Boulle, Olivier; Drouard, Marc; Mihai Miron, Ioan; Gaudin, Gilles [SPINTEC, UMR 8191, CEA/CNRS/UJF/GINP, INAC, F-38054 Grenoble (France); Garello, Kevin; Onur Avci, Can; Gambardella, Pietro [Department of Materials, ETH Zurich, Hönggerbergring 64, CH-8093 Zürich (Switzerland); Langer, Juergen; Ocker, Berthold [Singulus Technologies, Hanauer Landstr, 103, 63796 Kahl am Main (Germany)

    2014-01-27T23:59:59.000Z

    We report on the current-induced magnetization switching of a three-terminal perpendicular magnetic tunnel junction by spin-orbit torque and its read-out using the tunnelling magnetoresistance (TMR) effect. The device is composed of a perpendicular Ta/FeCoB/MgO/FeCoB stack on top of a Ta current line. The magnetization of the bottom FeCoB layer can be switched reproducibly by the injection of current pulses with density 5?×?10{sup 11}?A/m{sup 2} in the Ta layer in the presence of an in-plane bias magnetic field, leading to the full-scale change of the TMR signal. Our work demonstrates the proof of concept of a perpendicular spin-orbit torque magnetic memory cell.

  2. Topological Quantum Computation by Manipulating Quantum Tunneling Effect of the Toric Codes

    E-Print Network [OSTI]

    Su-Peng Kou

    2008-06-10T23:59:59.000Z

    Quantum computers are predicted to utilize quantum states to perform memory and to process tasks far faster than those of conventional classical computers. In this paper we show a new road towards building fault tolerance quantum computer by tuning quantum tunneling effect of the degenerate quantum states in topological order, instead of by braiding anyons. Using a designer Hamiltonian - the Wen-Plaquette model as an example, we study its quantum tunneling effect of the toric codes and show how to control the toric code to realize topological quantum computation (TQC). In particular, we give a proposal to the measurement of TQC. In the end the realization of the Wen-Plaquette model in cold atoms is discussed.

  3. Vacuum Tunneling in an Electroweak Model in Extra Dimensions With an External Flux

    E-Print Network [OSTI]

    Aaron J. Roy

    2009-04-14T23:59:59.000Z

    With the standard system for an SU(2) Higgs field in M_4 X S_1, the top and bottom component of the Higgs spinor have exactly the same coeficients for the quadratic and quadric terms. This makes the vacuum degenerate and thus there are no tunneling effects to zeroth order in radiative corrections of the vector gauge felds in the standard model with this extra dimensional geometry. However, if we include an external magnetic flux that permeates our manifold, then the top component of the Higgs spinor will have an additional term in its coefficient due to this theoretical flux with the usual charge assignments for the standard model. This extra term gives rise to two nondegenerate vacuum states for the resulting potential. We will compute the tunneling probability per unit time per unit volume between these vacuum states for the zero modes of our system as well as investigate the masses for the fields of the model using the false vacuum.

  4. Laser control of free-carrier density in solids through field-enhanced multiphonon tunneling recombination

    SciTech Connect (OSTI)

    Zheltikov, A. M.; Voronin, A. A. [Department of Physics, International Laser Center, M.V. Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Shneider, M. N.; Miles, R. B. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263 (United States)

    2011-02-01T23:59:59.000Z

    Enhancement of multiphonon tunneling recombination of free carriers in strong laser fields is shown to offer a mechanism whereby ultrafast carrier-density dynamics in a semiconductor can be controlled by properly shaped laser pulses. This regime of laser-solid interaction enables an ultrafast switching of optical and electric properties of semiconductor materials, suggesting new strategies for laser micromachining and nanomachining, optical data processing, and ultrafast plasmonics.

  5. Coherent generation of nonclassical light on a chip via photon-induced tunneling and blockade

    E-Print Network [OSTI]

    Andrei Faraon; Ilya Fushman; Dirk Englund; Nick Stoltz; Pierre Petroff; Jelena Vuckovic

    2008-04-17T23:59:59.000Z

    We report the observation of nonclassical light generated via photon blockade in a photonic crystal cavity with a strongly coupled quantum dot. By tuning the frequency of the probe laser with respect to the cavity and quantum dot resonance we can probe the system in either photon blockade or photon-induced tunneling regime. The transition from one regime to the other is confirmed by the measurement of the second order correlation that changes from anti-bunching to bunching.

  6. Fejer-type inequalities

    E-Print Network [OSTI]

    Mitroi, F C

    2011-01-01T23:59:59.000Z

    The aim of this paper is to present some new Fejer-type results for convex functions. Improvements of Young's inequality (the arithmetic-geometric mean inequality) and other applications to special means are pointed as well.

  7. Document Type: Subject Terms

    E-Print Network [OSTI]

    Major, Arkady

    Title: Authors: Source: Document Type: Subject Terms: Abstract: Full Text Word Count: ISSN at creating team results. In fact, it's priceless. Managers in Western corporations have received a lifetime

  8. A Planar Quantum Transistor Based on 2D-2D Tunneling in Double Quantum Well Heterostructures

    SciTech Connect (OSTI)

    Baca, W.E.; Blount, M.A.; Hafich, M.J.; Lyo, S.K.; Moon, J.S.; Reno, J.L.; Simmons, J.A.; Wendt, J.R.

    1998-12-14T23:59:59.000Z

    We report on our work on the double electron layer tunneling transistor (DELTT), based on the gate-control of two-dimensional -- two-dimensional (2D-2D) tunneling in a double quantum well heterostructure. While previous quantum transistors have typically required tiny laterally-defined features, by contrast the DELTT is entirely planar and can be reliably fabricated in large numbers. We use a novel epoxy-bond-and-stop-etch (EBASE) flip-chip process, whereby submicron gating on opposite sides of semiconductor epitaxial layers as thin as 0.24 microns can be achieved. Because both electron layers in the DELTT are 2D, the resonant tunneling features are unusually sharp, and can be easily modulated with one or more surface gates. We demonstrate DELTTs with peak-to-valley ratios in the source-drain I-V curve of order 20:1 below 1 K. Both the height and position of the resonant current peak can be controlled by gate voltage over a wide range. DELTTs with larger subband energy offsets ({approximately} 21 meV) exhibit characteristics that are nearly as good at 77 K, in good agreement with our theoretical calculations. Using these devices, we also demonstrate bistable memories operating at 77 K. Finally, we briefly discuss the prospects for room temperature operation, increases in gain, and high-speed.

  9. Nonlinear tunneling of optical soliton in 3 coupled NLS equation with symbolic computation

    SciTech Connect (OSTI)

    Mani Rajan, M.S., E-mail: senthilmanirajanofc@gmail.com [Department of Physics, Anna University, Madurai Region, Ramanathapuram (India); Mahalingam, A. [Department of Physics, Anna University, Chennai - 600 025 (India); Uthayakumar, A. [Department of Physics, Presidency College, Chennai - 600 005 (India)

    2014-07-15T23:59:59.000Z

    We investigated the soliton solution for N coupled nonlinear Schrödinger (CNLS) equations. These equations are coupled due to the cross-phase-modulation (CPM). Lax pair of this system is obtained via the Ablowitz–Kaup–Newell–Segur (AKNS) scheme and the corresponding Darboux transformation is constructed to derive the soliton solution. One and two soliton solutions are generated. Using two soliton solutions of 3 CNLS equation, nonlinear tunneling of soliton for both with and without exponential background has been discussed. Finally cascade compression of optical soliton through multi-nonlinear barrier has been discussed. The obtained results may have promising applications in all-optical devices based on optical solitons, study of soliton propagation in birefringence fiber systems and optical soliton with distributed dispersion and nonlinearity management. -- Highlights: •We consider the nonlinear tunneling of soliton in birefringence fiber. •3-coupled NLS (CNLS) equation with variable coefficients is considered. •Two soliton solutions are obtained via Darboux transformation using constructed Lax pair. •Soliton tunneling through dispersion barrier and well are investigated. •Finally, cascade compression of soliton has been achieved.

  10. Calibration of tip and sample temperature of a scanning tunneling microscope using a superconductive sample

    SciTech Connect (OSTI)

    Stocker, Matthias; Pfeifer, Holger; Koslowski, Berndt, E-mail: berndt.koslowski@uni-ulm.de [Institute of Solid State Physics, University of Ulm, D-89069 Ulm (Germany)

    2014-05-15T23:59:59.000Z

    The temperature of the electrodes is a crucial parameter in virtually all tunneling experiments. The temperature not only controls the thermodynamic state of the electrodes but also causes thermal broadening, which limits the energy resolution. Unfortunately, the construction of many scanning tunneling microscopes inherits a weak thermal link between tip and sample in order to make one side movable. Such, the temperature of that electrode is badly defined. Here, the authors present a procedure to calibrate the tip temperature by very simple means. The authors use a superconducting sample (Nb) and a standard tip made from W. Due to the asymmetry in the density of states of the superconductor (SC)—normal metal (NM) tunneling junction, the SC temperature controls predominantly the density of states while the NM controls the thermal smearing. By numerically simulating the I-V curves and numerically optimizing the tip temperature and the SC gap width, the tip temperature can be accurately deduced if the sample temperature is known or measureable. In our case, the temperature dependence of the SC gap may serve as a temperature sensor, leading to an accurate NM temperature even if the SC temperature is unknown.

  11. The tunneling hamiltonian representation of false vacuum decay V. Application to cosmological constant question

    E-Print Network [OSTI]

    A. W. Beckwith

    2004-08-10T23:59:59.000Z

    The tunneling Hamiltonian has proven to be a useful method in many body physics to treat particle tunneling between different states represented as wavefunctions. Here we apply a generalization of the way we formed appropriate wave functionals for charge density waves to how to present nucleation of an inflationary universe. This allows us to make a first order phase transition to initiate nucleation of an inflationary universe, in which tunneling between states which are wave functionals of a scalar quantum field are considered. Our prior article showed us how we can have particle - anti particle pairs as a model of how nucleation occurs and construct a potential which may permit formation of dark matter, using Sherrers k essence model construction. This same construction permits a definitive analysis of when conditions for pure cosmological constant behavior but no growth of density pertubations occur, largely as a matter of change of slope of a soliton-anti soliton pair during the nucleation process of a new universe.

  12. Soil erosion rates caused by wind and saltating sand stresses in a wind tunnel

    SciTech Connect (OSTI)

    Ligotke, M.W.

    1993-02-01T23:59:59.000Z

    Wind erosion tests were performed in a wind tunnel in support of the development of long-term protective barriers to cap stabilized waste sites at the Hanford Site. Controlled wind and saltating sand erosive stresses were applied to physical models of barrier surface layers to simulate worst-case eolian erosive stresses. The goal of these tests was to provide information useful to the design and evaluation of the surface layer composition of an arid-region waste site barrier concept that incorporates a deep fine-soil reservoir. A surface layer composition is needed that will form an armor resistant to eolian erosion during periods of extreme dry climatic conditions, especially when such conditions result in the elimination or reduction of vegetation by water deprivation or wildfire. Because of the life span required of Hanford waste barriers, it is important that additional work follow these wind tunnel studies. A modeling effort is planned to aid the interpretation of test results with respect to the suitability of pea gravel to protect the finite-soil reservoir during long periods of climatic stress. It is additionally recommended that wind tunnel tests be continued and field data be obtained at prototype or actual barrier sites. Results wig contribute to barrier design efforts and provide confidence in the design of long-term waste site caps for and regions.

  13. The impact of disorder on charge transport in three dimensional quantum dot resonant tunneling structures

    SciTech Connect (OSTI)

    Puthen-Veettil, B., E-mail: b.puthen-veettil@unsw.edu.au; Patterson, R.; König, D.; Conibeer, G.; Green, M. A. [Australian Centre for Advanced Photovoltaics, UNSW, Sydney 2052 (Australia)

    2014-10-28T23:59:59.000Z

    Efficient iso-entropic energy filtering of electronic waves can be realized through nanostructures with three dimensional confinement, such as quantum dot resonant tunneling structures. Large-area deployment of such structures is useful for energy selective contacts but such configuration is susceptible to structural disorders. In this work, the transport properties of quantum-dot-based wide-area resonant tunneling structures, subject to realistic disorder mechanisms, are studied. Positional variations of the quantum dots are shown to reduce the resonant transmission peaks while size variations in the device are shown to reduce as well as broaden the peaks. Increased quantum dot size distribution also results in a peak shift to lower energy which is attributed to large dots dominating transmission. A decrease in barrier thickness reduces the relative peak height while the overall transmission increases dramatically due to lower “series resistance.” While any shift away from ideality can be intuitively expected to reduce the resonance peak, quantification allows better understanding of the tolerances required for fabricating structures based on resonant tunneling phenomena/.

  14. Conductance enhancement due to interface magnons in electron-beam evaporated MgO magnetic tunnel junctions with CoFeB free layer deposited at different pressure

    SciTech Connect (OSTI)

    Guo, P.; Yu, G. Q.; Wei, H. X.; Han, X. F., E-mail: jiafengfeng@aphy.iphy.ac.cn, E-mail: xfhan@aphy.iphy.ac.cn [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Li, D. L.; Feng, J. F., E-mail: jiafengfeng@aphy.iphy.ac.cn, E-mail: xfhan@aphy.iphy.ac.cn [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); CRANN and School of Physics, Trinity College, Dublin 2 (Ireland); Kurt, H. [CRANN and School of Physics, Trinity College, Dublin 2 (Ireland); Department of Engineering Physics, Istanbul Medeniyet University, 34720 Istanbul (Turkey); Chen, J. Y.; Coey, J. M. D. [CRANN and School of Physics, Trinity College, Dublin 2 (Ireland)

    2014-10-21T23:59:59.000Z

    Electron-beam evaporated MgO-based magnetic tunnel junctions have been fabricated with the CoFeB free layer deposited at Ar pressure from 1 to 4 mTorr, and their tunneling process has been studied as a function of temperature and bias voltage. By changing the growth pressure, the junction dynamic conductance dI/dV, inelastic electron tunneling spectrum d²I/dV², and tunneling magnetoresistance vary with temperature. Moreover, the low-energy magnon cutoff energy E{sub C} derived from the conductance versus temperature curve agrees with interface magnon energy obtained directly from the inelastic electron tunneling spectrum, which demonstrates that interface magnons are involved in the electron tunneling process, opening an additional conductance channel and thus enhancing the total conductance.

  15. Evaluate and characterize mechanisms controlling transport, fate, and effects of army smokes in the aerosol wind tunnel: Transport, transformations, fate, and terrestrial ecological effects of hexachloroethane obscurant smokes

    SciTech Connect (OSTI)

    Cataldo, D.A.; Ligotke, M.W.; Bolton, H. Jr.; Fellows, R.J.; Van Voris, P.; McVeety, B.D.; Li, Shu-mei W.; McFadden, K.M.

    1989-09-01T23:59:59.000Z

    The terrestrial transport, chemical fate, and ecological effects of hexachloroethane (HC) smoke were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on exposure scenarios, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of HC smoke/obscurants is establishing the importance of environmental parameters such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and two soil types. HC aerosols were generated in a controlled atmosphere wind tunnel by combustion of hexachloroethane mixtures prepared to simulate normal pot burn rates and conditions. The aerosol was characterized and used to expose plant, soil, and other test systems. Particle sizes of airborne HC ranged from 1.3 to 2.1 {mu}m mass median aerodynamic diameter (MMAD), and particle size was affected by relative humidity over a range of 20% to 85%. Air concentrations employed ranged from 130 to 680 mg/m{sup 3}, depending on exposure scenario. Chlorocarbon concentrations within smokes, deposition rates for plant and soil surfaces, and persistence were determined. The fate of principal inorganic species (Zn, Al, and Cl) in a range of soils was assessed.

  16. Spent Fuel Transportation Package Response to the Baltimore Tunnel Fire Scenario

    SciTech Connect (OSTI)

    Adkins, Harold E.; Cuta, Judith M.; Koeppel, Brian J.; Guzman, Anthony D.; Bajwa, Christopher S.

    2006-11-15T23:59:59.000Z

    On July 18, 2001, a freight train carrying hazardous (non-nuclear) materials derailed and caught fire while passing through the Howard Street railroad tunnel in downtown Baltimore, Maryland. The United States Nuclear Regulatory Commission (USNRC), one of the agencies responsible for ensuring the safe transportation of radioactive materials in the United States, undertook an investigation of the train derailment and fire to determine the possible regulatory implications of this particular event for the transportation of spent nuclear fuel by railroad. Shortly after the accident occurred, the USNRC met with the National Transportation Safety Board (NTSB, the U.S. agency responsible for determining the cause of transportation accidents), to discuss the details of the accident and the ensuing fire. Following these discussions, the USNRC assembled a team of experts from the National Institute of Standards and Technology (NIST), the Center for Nuclear Waste Regulatory Analyses (CNWRA), and Pacific Northwest National Laboratory (PNNL) to determine the thermal conditions that existed in the Howard Street tunnel fire and analyze the effects of this fire on various spent fuel transportation package designs. The Fire Dynamics Simulator (FDS) code, developed by NIST, was used to determine the thermal environment present in the Howard Street tunnel during the fire. The FDS results were used as boundary conditions in the COBRA-SFS and ANSYS® computer codes to evaluate the thermal performance of different package designs. The staff concluded that larger transportation packages resembling the HOLTEC Model No. HI STAR 100 and TransNuclear Model No. TN-68 would withstand a fire with thermal conditions similar to those that existed in the Baltimore tunnel fire event with only minor damage to peripheral components. This is due to their sizable thermal inertia and design specifications in compliance with currently imposed regulatory requirements. The staff also concluded that some components of smaller transportation packages resembling the NAC Model No. LWT, despite placement within an ISO container, could degrade. USNRC staff evaluated the radiological consequences of the package responses to the Baltimore tunnel fire. Though components in some packages heated up beyond their service temperatures, the staff determined that there would be no significant dose as a result of the fire for any of these and similar packages.

  17. Infrared detection with high-{Tc} bolometers and response of Nb tunnel junctions to picosecond voltage pulses

    SciTech Connect (OSTI)

    Verghese, S.

    1993-05-01T23:59:59.000Z

    Oxide superconductors with high critical temperature {Tc} make sensitive thermometers for several types of infrared bolometers. The authors built composite bolometers with YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thermometers on sapphire substrates which have higher sensitivity than competing thermal detectors which operate at temperatures above 77 K. A 1 x 1 mm bolometer with gold black serving as the radiation absorber has useful sensitivity for wavelengths 20--100 {mu}m. A 3 x 3 mm bolometer with a bismuth film as the absorber operates from 20--100 {mu}m. High-{Tc} bolometers which are fabricated with micromachining techniques on membranes of Si or Si{sub 3}N{sub 4} have potential application to large-format arrays which are used for infrared imaging. A nonisothermal high-{Tc} bolometer can be fabricated on a membrane of yttria-stabilized zirconia (YSZ) which is in thermal contact with the heat sink along the perimeter of the membrane. A thermal analysis indicates that the YSZ membrane bolometer can have improved sensitivity compared to the sapphire bolometer for spectrometer applications. The quasiparticle tunneling current in a superconductor-insulator-superconductor (SIS) junction is highly nonlinear in the applied voltage. The authors have made the first measurement of the linear response of the quasiparticle current in a Nb/AlO{sub x}/Nb junction over a broad bandwidth from 75--200 GHz. Nonlinear measurements made with these pulses may provide information about the quasiparticle lifetime. Preliminary data from such measurements are presented.

  18. Proposal for the award of a contract for dismantling, removal and packaging of the existing Heating, Ventilation and Air-Conditioning (HVAC) systems in the PS tunnel

    E-Print Network [OSTI]

    2012-01-01T23:59:59.000Z

    Proposal for the award of a contract for dismantling, removal and packaging of the existing Heating, Ventilation and Air-Conditioning (HVAC) systems in the PS tunnel

  19. Calculating electronic tunnel currents in networks of disordered irregularly shaped nanoparticles by mapping networks to arrays of parallel nonlinear resistors

    SciTech Connect (OSTI)

    Aghili Yajadda, Mir Massoud [CSIRO Manufacturing Flagship, P.O. Box 218, Lindfield NSW 2070 (Australia)

    2014-10-21T23:59:59.000Z

    We have shown both theoretically and experimentally that tunnel currents in networks of disordered irregularly shaped nanoparticles (NPs) can be calculated by considering the networks as arrays of parallel nonlinear resistors. Each resistor is described by a one-dimensional or a two-dimensional array of equal size nanoparticles that the tunnel junction gaps between nanoparticles in each resistor is assumed to be equal. The number of tunnel junctions between two contact electrodes and the tunnel junction gaps between nanoparticles are found to be functions of Coulomb blockade energies. In addition, the tunnel barriers between nanoparticles were considered to be tilted at high voltages. Furthermore, the role of thermal expansion coefficient of the tunnel junction gaps on the tunnel current is taken into account. The model calculations fit very well to the experimental data of a network of disordered gold nanoparticles, a forest of multi-wall carbon nanotubes, and a network of few-layer graphene nanoplates over a wide temperature range (5-300 K) at low and high DC bias voltages (0.001 mV–50 V). Our investigations indicate, although electron cotunneling in networks of disordered irregularly shaped NPs may occur, non-Arrhenius behavior at low temperatures cannot be described by the cotunneling model due to size distribution in the networks and irregular shape of nanoparticles. Non-Arrhenius behavior of the samples at zero bias voltage limit was attributed to the disorder in the samples. Unlike the electron cotunneling model, we found that the crossover from Arrhenius to non-Arrhenius behavior occurs at two temperatures, one at a high temperature and the other at a low temperature.

  20. A Modeling Study Evaluating the Thermal-Hydrological Conditions In and Near Waste Emplacement Tunnels At Yucca Mountain

    SciTech Connect (OSTI)

    J.T. Birkholzer; N. Halecky; S.W> Webb; P.F. Peterson; G.S. Bodvarsson

    2006-10-11T23:59:59.000Z

    In heated tunnels such as those designated for emplacement of radioactive waste at the proposed geologic repository at Yucca Mountain, temperature gradients cause natural convection processes that may significantly influence the moisture conditions in the tunnels and in the surrounding fractured rock. Large-scale convection cells in the heated tunnels would provide an effective mechanism for turbulent mixing and axial transport of vapor generated from evaporation of pore water in the nearby formation. As a result, vapor would be transported from the elevated-temperature sections of the tunnels into cool end sections (where no waste is emplaced), would condense there, and subsequently drain into underlying rock units. To study these processes, we have developed a new simulation method that couples existing tools for simulating thermal-hydrological (TH) conditions in the fractured formation with a module that approximates turbulent natural convection in heated emplacement drifts. The new method simultaneously handles (1) the flow and energy transport processes in the fractured rock, (2) the flow and energy transport processes in the cavity, and (3) the heat and mass exchange at the rock-cavity interface. An application is presented studying the future TH conditions within and near a representative waste emplacement tunnel at Yucca Mountain. Particular focus is on the potential for condensation along the emplacement section, a possible result of heat output differences between individual waste packages.

  1. Tunneling spectroscopy of superconducting MoN and NbTiN grown by atomic layer deposition

    SciTech Connect (OSTI)

    Groll, Nickolas R., E-mail: ngroll@anl.gov; Klug, Jeffrey A.; Claus, Helmut; Pellin, Michael J.; Proslier, Thomas, E-mail: proslier@anl.gov [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Cao, Chaoyue; Becker, Nicholas G.; Zasadzinski, John F. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, Illinois Institute of Technology, Chicago, Illinois 60616 (United States); Altin, Serdar [Fen Edebiyat Fakultesi, Fizik Bolumu, Inonu Universitesi, 44280 Malatya (Turkey)

    2014-03-03T23:59:59.000Z

    A tunneling spectroscopy study is presented of superconducting MoN and Nb{sub 0.8}Ti{sub 0.2}N thin films grown by atomic layer deposition (ALD). The films exhibited a superconducting gap of 2?meV and 2.4?meV, respectively, with a corresponding critical temperature of 11.5?K and 13.4?K, among the highest reported T{sub c} values achieved by the ALD technique. Tunnel junctions were obtained using a mechanical contact method with a Au tip. While the native oxides of these films provided poor tunnel barriers, high quality tunnel junctions with low zero bias conductance (below ?10%) were obtained using an artificial tunnel barrier of Al{sub 2}O{sub 3} on the film's surface grown ex situ by ALD. We find a large critical current density on the order of 4?×?10{sup 6}?A/cm{sup 2} at T?=?0.8T{sub c} for a 60?nm MoN film and demonstrate conformal coating capabilities of ALD onto high aspect ratio geometries. These results suggest that the ALD technique offers significant promise for thin film superconducting device applications.

  2. High-stability cryogenic scanning tunneling microscope based on a closed-cycle cryostat

    SciTech Connect (OSTI)

    Hackley, Jason D.; Kislitsyn, Dmitry A.; Beaman, Daniel K.; Nazin, George V., E-mail: gnazin@uoregon.edu [Department of Chemistry and Biochemistry, 1253 University of Oregon, Eugene, Oregon 97403 (United States); Ulrich, Stefan [RHK Technology, Inc., 1050 East Maple Road, Troy, Michigan 48083 (United States)

    2014-10-15T23:59:59.000Z

    We report on the design and operation of a cryogenic ultra-high vacuum (UHV) scanning tunneling microscope (STM) coupled to a closed-cycle cryostat (CCC). The STM is thermally linked to the CCC through helium exchange gas confined inside a volume enclosed by highly flexible rubber bellows. The STM is thus mechanically decoupled from the CCC, which results in a significant reduction of the mechanical noise transferred from the CCC to the STM. Noise analysis of the tunneling current shows current fluctuations up to 4% of the total current, which translates into tip-sample distance variations of up to 1.5 picometers. This noise level is sufficiently low for atomic-resolution imaging of a wide variety of surfaces. To demonstrate this, atomic-resolution images of Au(111) and NaCl(100)/Au(111) surfaces, as well as of carbon nanotubes deposited on Au(111), were obtained. Thermal drift analysis showed that under optimized conditions, the lateral stability of the STM scanner can be as low as 0.18 Å/h. Scanning Tunneling Spectroscopy measurements based on the lock-in technique were also carried out, and showed no detectable presence of noise from the closed-cycle cryostat. Using this cooling approach, temperatures as low as 16 K at the STM scanner have been achieved, with the complete cool-down of the system typically taking up to 12 h. These results demonstrate that the constructed CCC-coupled STM is a highly stable instrument capable of highly detailed spectroscopic investigations of materials and surfaces at the atomic scale.

  3. Dust around Type Ia supernovae

    E-Print Network [OSTI]

    Wang, Lifan

    2005-01-01T23:59:59.000Z

    Dust around Type Ia supernovae Lifan Wang 1,2 LawrenceIa. Subject headings: Supernovae: General, Dust, Extinctionline) bands for Type Ia supernovae. (a), upper panel, shows

  4. Tunneling and traversal of ultracold three-level atoms through vacuum-induced potentials

    SciTech Connect (OSTI)

    Badshah, Fazal; Irfan, Muhammad; Qamar, Shahid [Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650 (Pakistan); Qamar, Sajid [Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan)

    2011-09-15T23:59:59.000Z

    The passage of ultracold three-level atoms through the potential induced by the vacuum cavity mode is discussed using cascade atomic configuration. We study the tunneling or traversal time of the ultracold atoms via a bimodal high-Q cavity. It is found that the phase time, which may be considered as a measure for the time required to traverse the cavity, exhibits superclassical and subclassical behaviors. Further, the dark states and interference effects in cascade atomic configuration may influence the passage time of the atom through the cavity.

  5. Quantum tunneling in ^{277}112 and its alpha-decay chain

    E-Print Network [OSTI]

    C. Samanta; D. N. Basu; P. Roy Chowdhury

    2007-08-31T23:59:59.000Z

    The $\\alpha$-decay half lives of nuclei in the decay from element $^{277}112$ are calculated in a WKB framework using DDM3Y interaction and experimental Q-values. Theoretical estimation of half lives in the same quantum tunneling model, using Q-values from the mass formula of Muntian-Hofmann-Patyk-Sobiczewski, are also presented. Calculated results furnish corroborating evidence for the experimental findings at RIKEN and GSI. Certain discrepancies indicate necessity of a better mass formula. Further experimental data with higher statistics would also be useful.

  6. Eliashberg Function in an Amorphous Simple Metal Alloy Sn1-Xcux Determined by Electron-Tunneling

    E-Print Network [OSTI]

    WATSON, PW; Naugle, Donald G.

    1995-01-01T23:59:59.000Z

    PHYSICAL REVIEW B VOLUME 51, NUMBER 1 1 JANUARY 1995-I Eliashberg function in an amorphous simple metal alloy Sn1 Cu determined by electron tunneling P. W. Watson III NMT-5, MS E506, Los Alamos National Laboratory, Los Alamos, New Mexico 87545... frequencies which was identical to that of Berg- mann. For very short mean free paths (high-resistivity alloys) Meisel and Cote invoked the Pippard condition in an ad hoc fashion and predicted an co dependence. The microscopic models of the electron...

  7. Spent Fuel Transportation Cask Response to the Caldecott Tunnel Fire Scenario

    SciTech Connect (OSTI)

    Adkins, Harold E.; Koeppel, Brian J.; Cuta, Judith M.

    2007-01-01T23:59:59.000Z

    On April 7, 1982, a tank truck and trailer carrying 8,800 gallons of gasoline was involved in an accident in the Caldecott tunnel on State Route 24 near Oakland, California. The tank trailer overturned and subsequently caught fire. The United States Nuclear Regulatory Commission (USNRC), one of the agencies responsible for ensuring the safe transportation of radioactive materials in the United States, undertook analyses to determine the possible regulatory implications of this particular event for the transportation of spent nuclear fuel by truck. The Fire Dynamics Simulator (FDS) code developed by National Institute of Standards and Technology (NIST) was used to determine the thermal environment in the Caldecott tunnel during the fire. The FDS results were used to define boundary conditions for a thermal transient model of a truck transport cask containing spent nuclear fuel. The Nuclear Assurance Corporation (NAC) Legal Weight Truck (LWT) transportation cask was selected for this evaluation, as it represents a typical truck (over-the-road) cask, and can be used to transport a wide variety of spent nuclear fuels. Detailed analysis of the cask response to the fire was performed using the ANSYS® computer code to evaluate the thermal performance of the cask design in this fire scenario. This report describes the methods and approach used to assess the thermal response of the selected cask design to the conditions predicted in the Caldecott tunnel fire. The results of the analysis are presented in detail, with an evaluation of the cask response to the fire. The staff concluded that some components of smaller transportation casks resembling the NAC LWT, despite placement within an ISO container, could degrade significantly. Small transportation casks similar to the NAC LWT would probably experience failure of seals in this severe accident scenario. USNRC staff evaluated the radiological consequences of the cask response to the Caldecott tunnel fire. Although some components heated up beyond their service temperatures, the staff determined that there would be no significant release as a result of the fire for the NAC LWT and similar casks.

  8. Error propagation equations for estimating the uncertainty in high-speed wind tunnel test results

    SciTech Connect (OSTI)

    Clark, E.L.

    1994-07-01T23:59:59.000Z

    Error propagation equations, based on the Taylor series model, are derived for the nondimensional ratios and coefficients most often encountered in high-speed wind tunnel testing. These include pressure ratio and coefficient, static force and moment coefficients, dynamic stability coefficients, and calibration Mach number. The error equations contain partial derivatives, denoted as sensitivity coefficients, which define the influence of free-steam Mach number, M{infinity}, on various aerodynamic ratios. To facilitate use of the error equations, sensitivity coefficients are derived and evaluated for five fundamental aerodynamic ratios which relate free-steam test conditions to a reference condition.

  9. Dynamical properties of three terminal magnetic tunnel junctions: Spintronics meets spin-orbitronics

    SciTech Connect (OSTI)

    Tomasello, R. [Department of Computer Science, Modeling, Electronics and System Science, University of Calabria, Rende (CS) (Italy)] [Department of Computer Science, Modeling, Electronics and System Science, University of Calabria, Rende (CS) (Italy); Carpentieri, M., E-mail: m.carpentieri@poliba.it [Department of Electrical and Information Engineering, Politecnico of Bari, via E. Orabona 4, I-70125 Bari (Italy); Finocchio, G. [Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, C.da di Dio, I-98166 Messina (Italy)] [Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, C.da di Dio, I-98166 Messina (Italy)

    2013-12-16T23:59:59.000Z

    This Letter introduces a micromagnetic model able to characterize the magnetization dynamics in three terminal magnetic tunnel junctions, where the effects of spin-transfer torque and spin-orbit torque are taken into account. Our results predict that the possibility to separate electrically those two torque sources is very promising from a technological point of view for both next generation of nanoscale spintronic oscillators and microwave detectors. A scalable synchronization scheme based on the parallel connection of those three terminal devices is also proposed.

  10. Parametric excitation in a magnetic tunnel junction-based spin torque oscillator

    SciTech Connect (OSTI)

    Dürrenfeld, P.; Iacocca, E. [Department of Physics, University of Gothenburg, 412 96 Gothenburg (Sweden); Åkerman, J. [Department of Physics, University of Gothenburg, 412 96 Gothenburg (Sweden); Materials Physics, School of ICT, KTH-Royal Institute of Technology, Electrum 229, 164 40 Kista (Sweden); Muduli, P. K. [Department of Physics, University of Gothenburg, 412 96 Gothenburg (Sweden); Department of Physics, Indian Institute of Technology, Delhi, 110016 New Delhi (India)

    2014-02-03T23:59:59.000Z

    Using microwave current injection at room temperature, we demonstrate parametric excitation of a magnetic tunnel junction (MTJ)-based spin-torque oscillator (STO). Parametric excitation is observed for currents below the auto-oscillation threshold, when the microwave current frequency f{sub e} is twice the STO free-running frequency f{sub 0}. Above threshold, the MTJ becomes parametrically synchronized. In the synchronized state, the STO exhibits an integrated power up to 5 times higher and a linewidth reduction of two orders of magnitude, compared to free-running conditions. We also show that the parametric synchronization favors single mode oscillations in the case of multimode excitation.

  11. An analysis of the induced flow downstream between oscillating wings in a wind tunnel

    E-Print Network [OSTI]

    Morgan, Barry Erwin

    1970-01-01T23:59:59.000Z

    AN ANALYSIS OF THE INDUCED FLOW DOWNSTREAM BETWEEN OSCILLATING WINGS IN A WIND TIMBAL A Thesis by BARRY ERWIN MORGAN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER... OF SCIENCE May 1970 Major Subject; Aerospace Engineering AN ANALYSIS OF THE INDUCED FLOW DOWNSTREAM BETWEEN OSCILLATING WINGS IN A WIND TUNNEL A Thesis by BARRY ERWIN MORGAN Approved as to style and content by: rman of Committee) (Hea of Depart ent...

  12. Wolter type i LAMAR

    SciTech Connect (OSTI)

    Catura, R.C.; Joki, E.G.

    1981-11-01T23:59:59.000Z

    Observational objectives for the LAMAR and their influence on the instrument design are discussed. It is concluded that the most important design parameter is the angular resolution of the LAMAR modules since it so strongly influences sensitivity, optical identifications, source confusion, spectral resolution for objective gratings and the ability to resolve small extended sources. A high resolution Wolter Type I LAMAR module is described, its hardware status discussed, and the performance of a LAMAR observatory presented. A promising technique for enhancing the reflectivity of Wolter Type I X-ray optics in a selected bandpass at high energy has been investigated and the performance of the LAMAR module, utilizing this method, has been calculated.

  13. Rappels: 4) Piles Types abstraits de donnes (Abstract Data Type)

    E-Print Network [OSTI]

    Hamel, Sylvie

    Rappels: 4) Piles #12;Types abstraits de données (Abstract Data Type) IFT2015, A2009, Sylvie Hamel Université de Montréal 1Piles Type de données Un ensemble de valeurs Un ensemble d'opérations Structure de Université de Montréal 2Piles #12;Type abstrait de données PILE (§4.2) Garde en mémoire des objets

  14. Temporal and Dose Kinetics of Tunnel Relaxation of Non-Equilibrium Near-Interfacial Charged Defects in Insulators

    E-Print Network [OSTI]

    Zebrev, Gennady I

    2015-01-01T23:59:59.000Z

    This paper is devoted mainly to mathematical aspects of modeling and simulation of tunnel relaxation of nonequilibrium charged oxide traps located at/near the interface insulator - conductive channel, for instance in irradiated MOS devices. The generic form of the tunnel annealing response function was derived from the rate equation for the charged defect buildup and annealing as a linear superposition of the responses of different defects with different time constants. Using this linear response function, a number of important practical problems are analyzed and discussed. Combined tunnel and thermal or RICN annealing, power-like temporal relaxation after a single ion strike into the gate oxide, are described in context of general approach.

  15. The Tunneling Hamiltonian Representation of False Vacuum Decay: IV. Application to formation of Dark Matter in nucleating universe

    E-Print Network [OSTI]

    A. W. Beckwith

    2004-07-28T23:59:59.000Z

    The tunneling Hamiltonian has proven to be a useful method in many body physics to treat particle tunneling between different states represented as wavefunctions. Here, we apply a generalization of the way we formed appropriate wave functionals for CDW on how to present nucleation of an inflationary universe. This allows us to make a generalization of the model used for inflation where the infation is trapped in a false vacuum and, after tunning makes a first order phase transition to initiate nucleation of an inflationary universe, in which tunneling between states which are wave functionals between states which wavefunctionals of a scalar quantum field are considered.We explain how we can have particle-anti particle pairs as a model of how nucleation occurs and construct a potential which may permit formation of dark matter using Scherrers k-essence model construction.

  16. FULL-SCALE, WIND TUNNEL AND CFD WIND ENGINEERING STUDIES A variety of methods can be used to obtain wind engineering design information. These include

    E-Print Network [OSTI]

    Savory, Eric

    FULL-SCALE, WIND TUNNEL AND CFD WIND ENGINEERING STUDIES A variety of methods can be used to obtain wind engineering design information. These include codes of practice, full-scale, wind tunnel are listed in the table below: Table 1. Relative advantages and disadvantages of wind engineering techniques

  17. Atomic and electronic structure of monolayer graphene on 6H-SiC(0001)(3 3) : a scanning tunneling microscopy study.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Atomic and electronic structure of monolayer graphene on 6H-SiC(0001)(3 × 3) : a scanning tunneling of the atomic and electronic structure of graphene monolayer islands on the 6H-SiC(0001)(3×3) (SiC(3×3)) surface reconstruction using scanning tunneling microscopy (STM) and spectroscopy (STS). The orientation of the graphene

  18. Fabrication of multilayer single-electron tunneling devices E. H. Visscher, S. M. Verbrugh, J. Lindeman, P. Hadley, and J. E. Mooij

    E-Print Network [OSTI]

    Fabrication of multilayer single-electron tunneling devices E. H. Visscher, S. M. Verbrugh, J for the fabrication of multilevel single-electron tunneling SET devices. Using this process, we have fabricated SET. Lindeman, P. Hadley, and J. E. Mooij Department of Applied Physics and Delft Institute for Micro-Electronics

  19. Strong Room-temperature Negative Transconductance In An Axial Si/Ge Hetero-nanowire Tunneling Field-effect Transistor

    SciTech Connect (OSTI)

    Zhang, Peng; Le, Son T.; Hou, Xiaoxiao; Zaslavsky, A.; Perea, Daniel E.; Dayeh, Shadi A.; Picraux, Samuel T.

    2014-08-11T23:59:59.000Z

    We report on room-temperature negative transconductance (NTC) in axial Si/Ge hetero-nanowire tunneling field-effect transistors (TFETs). The NTC produces a current peak-to-valley ratio > 45, a high value for a Si-based device. We characterize the NTC characteristics over a range of gate VG and drain VD voltages, finding that NTC persists down to VD = –50 mV. The physical mechanism responsible for the NTC is the VG-induced depletion in the p-Ge section that eventually reduces the maximum electric field that triggers the tunneling ID, as confirmed via three-dimensional TCAD simulations.

  20. Manipulation of subsurface carbon nanoparticles in Bi?Sr?CaCu?O8+? using a scanning tunneling microscope

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Stollenwerk, A. J.; Gu, G.; Hurley, N.; Beck, B.; Spurgeon, K.; Kidd, T. E.

    2015-03-01T23:59:59.000Z

    We present evidence that subsurface carbon nanoparticles in Bi?Sr?CaCu?O8+? can be manipulated with nanometer precision using a scanning tunneling microscope. High resolution images indicate that most of the carbon particles remain subsurface after transport observable as a local increase in height as the particle pushes up on the surface. Tunneling spectra in the vicinity of these protrusions exhibit semiconducting characteristics with a band gap of approximately 1.8 eV, indicating that the incorporation of carbon locally alters the electronic properties near the surface.

  1. Weak-Light, Zero to -\\pi Lossless Kerr-Phase Gate in Quantum-well System via Tunneling Interference Effect

    E-Print Network [OSTI]

    Shi, Y L; Wu, J X; Zhu, C J; Xu, J P; Yang, Y P

    2015-01-01T23:59:59.000Z

    We examine a Kerr phase gate in a semiconductor quantum well structure based on the tunnelling interference effect. We show that there exist a specific signal field detuning, at which the absorption/amplification of the probe field will be eliminated with the increase of the tunnelling interference. Simultaneously, the probe field will acquire a -\\pi phase shift at the exit of the medium. We demonstrate with numerical simulations that a complete 180^\\circ phase rotation for the probe field at the exit of the medium is achieved, which may result in many applications in information science and telecommunication.

  2. Corrected entropy of the rotating black hole solution of the new massive gravity using the tunneling method and Cardy formula

    SciTech Connect (OSTI)

    Mirza, Behrouz; Sherkatghanad, Zeinab [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2011-05-15T23:59:59.000Z

    We study the AdS rotating black hole solution for the Bergshoeff-Hohm-Townsend massive gravity in three dimensions. The field equations of the asymptotically AdS black hole of the static metric can be expressed as the first law of thermodynamics, i.e. dE=TdS-PdV. The corrected Hawking-like temperature and entropy of the asymptotically AdS rotating black hole are calculated using the Cardy formula and the tunneling method. Comparison of these methods will help identify the unknown leading correction parameter {beta}{sub 1} in the tunneling method.

  3. Proximity detector circuits: an attractive alternative to tunnel diode oscillators for contactless measurements in pulsed magnetic fields

    SciTech Connect (OSTI)

    Altarawneh, Moaz M [Los Alamos National Laboratory; Mielke, Charles H [Los Alamos National Laboratory

    2009-01-01T23:59:59.000Z

    A new radio frequency oscillator circuit based on a proximity detector integrated circuit is described as an alternative for the traditional tunnel diode oscillator used for pulsed magnetic field measurements at low temperatures. The new circuit has been successfully applied to measure the superconducting upper critical field in Ba{sub 0.55}K{sub 0.45}Fe{sub 2}As{sub 2} single crystfl.ls up to 60 T. The new circuit design avoids many of the problems associated with tunnel diode circuits while keeping the advantages of contact less measurements in pulsed magnets.

  4. GaN-based vertical-cavity laser performance improvements using tunnel-junction-cascaded active regions

    SciTech Connect (OSTI)

    Piprek, Joachim, E-mail: piprek@nusod.org [NUSOD Institute LLC, P.O. Box 7204, Newark, Delaware 19714 (United States)

    2014-07-07T23:59:59.000Z

    This Letter investigates the output power enhancement achieved by tunnel junction insertion into the InGaN multi-quantum well (MQW) active region of a 410?nm vertical-cavity surface-emitting laser which enables the repeated use of carriers for light generation (carrier recycling). While the number of quantum wells remains unchanged, the tunnel junction eliminates absorption caused by the non-uniform MQW carrier distribution. The thermal resistance drops and the excess bias lead to a surprisingly small rise in self-heating.

  5. Low-temperature magnetic characterization of optimum and etch-damaged in-plane magnetic tunnel junctions

    SciTech Connect (OSTI)

    Kan, Jimmy J.; Gottwald, Matthias; Fullerton, Eric E. [Center for Magnetic Recording Research, University of California, San Diego, La Jolla, California 92093 (United States)] [Center for Magnetic Recording Research, University of California, San Diego, La Jolla, California 92093 (United States); Lee, Kangho; Kang, Seung H. [Advanced Technology, Qualcomm, Inc., San Diego, California 92121 (United States)] [Advanced Technology, Qualcomm, Inc., San Diego, California 92121 (United States)

    2013-09-21T23:59:59.000Z

    We describe low-temperature characterization of magnetic tunnel junctions (MTJs) patterned by reactive ion etching for spin-transfer-torque magnetic random access memory. Magnetotransport measurements of typical MTJs show increasing tunneling magnetoresistance (TMR) and larger coercive fields as temperature is decreased down to 10 K. However, MTJs selected from the high-resistance population of an MTJ array exhibit stable intermediate magnetic states when measured at low temperature and show TMR roll-off below 100 K. These non-ideal low-temperature behaviors arise from edge damage during the etch process and can have negative impacts on thermal stability of the MTJs.

  6. Mechanism for instability and formation of an inhomogeneous state in a superconductor with intensive tunnel injection

    SciTech Connect (OSTI)

    Nevirkovets, I.P.; Rudenko, E.M.

    1985-05-01T23:59:59.000Z

    The spatial distribution of the two-gap inhomogeneous state of superconducting tin films was investigated experimentally using a number of detectors at injection voltage V/sub i/approx. =2..delta../e. It was found that the initiation of the inhomogeneous state depended on how the current was fed into the generator. The spatial structure of the inhomogeneous state and the instability in the form of a negative voltage jump on the current-voltage characteristic of the generator, which leads to the inhomogeneous state, were found to be very sensitive to weak magnetic fields. The form of the current-voltage characteristic of low-resistance tunnel junctions for V/sub i/approx. =2..delta../e was very dependent on the dimensions of the junction and the transparency of the barrier. Instability was observed only for tunnel junctions whose dimensions exceeded the Josephson penetration depth of the magnetic field. The results are interpreted in terms of the presence in the junction of an inhomogeneous distribution of the constant component of the current, inherent in distributed Josephson junctions.

  7. Tunneling into black hole, escape from black hole, reflection from horizon and pair creation

    E-Print Network [OSTI]

    V. V. Flambaum

    2004-08-05T23:59:59.000Z

    Within classical general relativity, a particle cannot reach the horizon of a black hole during a finite time, in the reference frame of an external observer; a particle inside cannot escape from a black hole; and the horizon does not produce any reflection. We argue that these processes may possibly be allowed in the quantum world. It is known that quantum mechanics allows pair creation at the horizon (one particle inside, another particle outside) and Hawking radiation. One can extend this idea to propose other processes. Tunneling of an external particle inside black hole may be produced by the creation of a pair at the horizon, followed by the annihilation of one created particle with the initial particle outside, with the other created particle appearing inside. Escape of a particle from a black hole may result from the creation of a pair, followed by the annihilation of one created particle with the particle inside, with the other created particle appearing outside. The escape may allow the transfer of information to the outside.Finally, the reflection of an external particle from the horizon may be modelled by a combination of the two processes presented above. The relationship between these "pair creation-annihilation'' mechanisms and the "horizon tunneling" calculations [1-5] is discussed.

  8. Power and efficiency analysis of a realistic resonant tunneling diode thermoelectric

    SciTech Connect (OSTI)

    Agarwal, Akshay; Muralidharan, Bhaskaran, E-mail: bm@ee.iitb.ac.in [Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai-400076 (India)

    2014-07-07T23:59:59.000Z

    Low-dimensional systems with sharp features in the density of states have been proposed as a means for improving the efficiency of thermoelectric devices. Quantum dot systems, which offer the sharpest density of states achievable, however, suffer from low power outputs while bulk (3-D) thermoelectrics, while displaying high power outputs, offer very low efficiencies. Here, we analyze the use of a resonant tunneling diode structure that combines the best of both aspects, that is, density of states distortion with a finite bandwidth due to confinement that aids the efficiency and a large number of current carrying transverse modes that enhances the total power output. We show that this device can achieve a high power output (?0.3?MW?m{sup 2}) at efficiencies of ?40% of the Carnot efficiency due to the contribution from these transverse momentum states at a finite bandwidth of kT?2. We then provide a detailed analysis of the physics of charge and heat transport with insights on parasitic currents that reduce the efficiency. Finally, a comparison between the resonant tunneling diode and a quantum dot device with comparable bandwidth reveals that a similar performance requires ultra-dense areal quantum dot densities of ?10{sup 12}/cm{sup 2}.

  9. Patency of Femoral Tunneled Hemodialysis Catheters and Factors Predictive of Patency Failure

    SciTech Connect (OSTI)

    Burton, Kirsteen R. [University Health Network, University of Toronto, Department of Medical Imaging, Division of Vascular and Interventional Radiology (Canada); Guo, Lancia L. Q. [University of Calgary, Department of Radiology (Canada); Tan, Kong T.; Simons, Martin E.; Sniderman, Kenneth W.; Kachura, John R.; Beecroft, John R.; Rajan, Dheeraj K., E-mail: dheeraj.rajan@uhn.on.ca [University Health Network, University of Toronto, Department of Medical Imaging, Division of Vascular and Interventional Radiology (Canada)

    2012-12-15T23:59:59.000Z

    Purpose: To determine the patency rates of and factors associated with increased risk of patency failure in patients with femoral vein tunneled hemodialysis catheters. Methods: All femoral tunneled catheter insertions from 1996 to 2006 were reviewed, during which time 123 catheters were inserted. Of these, 66 were exchanges. Patients with femoral catheter failure versus those with femoral catheter patency were compared. Confounding factors, such as demographic and procedural factors, were incorporated and assessed using univariate and multivariable Cox proportional hazards regression analyses. Results: Mean catheter primary patency failure time was 96.3 days (SE 17.9 days). Primary patency at 30, 60, 90, and 180 days was 53.8%, 45.4%, 32.1%, and 27.1% respectively. Crude rates of risk of catheter failure did not suggest a benefit for patients receiving catheters introduced from one side versus the other, but more cephalad location of catheter tip was associated with improved patency. Multivariate analysis showed that patients whose catheters were on the left side (p = 0.009), were of increasing age at the time of insertion (p = 0.002) and that those who had diabetes (p = 0.001) were at significantly greater risk of catheter failure. The catheter infection rate was 1.4/1000 catheter days. Conclusion: Patients who were of a more advanced age and had diabetes were at greater risk of femoral catheter failure, whereas those who received femoral catheters from the right side were less at risk of catheter failure.

  10. Hanle measurements of electrodeposited Fe/GaAs spin tunnel contacts

    SciTech Connect (OSTI)

    Majumder, Sarmita; Hohertz, Donna; McNeil, James; Kavanagh, Karen L. [Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); SpringThorpe, Anthony [National Research Council, 1200 Montreal Rd, Ottawa, Ontario K1A 0R6 (Canada)

    2014-03-28T23:59:59.000Z

    We report spin transport in electrodeposited Fe/n-GaAs tunnel diodes via three-terminal Hanle measurements. For temperatures between 20?K and 150?K, the spin resistance was up to 20 times higher than expected from theoretical calculations and 1000 times larger compared to a vacuum-deposited counterpart. This higher spin resistance was correlated with a higher contact resistance, and a higher concentration of oxygen impurities in the electrodeposited Fe film and interface, as detected via x-ray photoelectron and Auger spectroscopies, and inferred from Fe film nucleation rates. These results can be explained via a small effective tunnel-contact area of 5%, but extra spin filtering via interfacial states or magnetic oxide layers cannot be ruled out. The spin diffusion times (8.5 ± 0.4?ns to 1.8 ± 0.4?ns, for 20?K to 150?K) extracted from Lorentzian fits were in good agreement with values obtained from earlier 4-terminal Hanle measurements (7.8 ± 0.4?ns to 3.2 ± 0.4?ns, for 25?K to 77?K), both 10 times slower than reported vacuum-deposited contacts.

  11. Tunneling probability for the birth of an asymptotically de Sitter universe

    SciTech Connect (OSTI)

    Acacio de Barros, J. [CSLI, 220 Panama Street, Stanford University, Stanford, California 94305-4115 (United States); Correa Silva, E. V.; Monerat, G. A.; Oliveira-Neto, G. [Departamento de Matematica e Computacao, Faculdade de Tecnologia, Universidade do Estado do Rio de Janeiro, Rodovia Presidente Dutra Km 298, Polo Industrial, CEP 27537-000, Resende-RJ (Brazil); Ferreira Filho, L. G. [Departamento de Mecanica e Energia, Faculdade de Tecnologia, Universidade do Estado do Rio de Janeiro, Rodovia Presidente Dutra Km 298, Polo Industrial, CEP 27537-000, Resende-RJ (Brazil); Romildo, P. Jr. [Departamento de Fisica, Instituto de Ciencias Exatas, Universidade Federal de Juiz de Fora, CEP 36036-330, Juiz de Fora, Minas Gerais (Brazil)

    2007-05-15T23:59:59.000Z

    In the present work, we quantize a closed Friedmann-Robertson-Walker model in the presence of a positive cosmological constant and radiation. It gives rise to a Wheeler-DeWitt equation for the scale factor which has the form of a Schroedinger equation for a potential with a barrier. We solve it numerically and determine the tunneling probability for the birth of a asymptotically DeSitter, inflationary universe, initially, as a function of the mean energy of the initial wave function. Then, we verify that the tunneling probability increases with the cosmological constant, for a fixed value of the mean energy of the initial wave function. Our treatment of the problem is more general than previous ones, based on the WKB approximation. That is the case because we take into account the fact that the scale factor (a) cannot be smaller than zero. It means that, one has to introduce an infinity potential wall at a=0, which forces any wave packet to be zero there. That condition introduces new results, in comparison with previous works.

  12. The tunneling model of laser-induced ionization and its failure at low frequencies

    E-Print Network [OSTI]

    H. R. Reiss

    2014-05-11T23:59:59.000Z

    The tunneling model of ionization applies only to longitudinal fields: quasistatic electric fields that do not propagate. Laser fields are transverse: plane wave fields that possess the ability to propagate. Although there is an approximate connection between the effects of longitudinal and transverse fields in a useful range of frequencies, that equivalence fails completely at very low frequencies. Insight into this breakdown is given by an examination of radiation pressure, which is a unique transverse-field effect whose relative importance increases rapidly as the frequency declines. Radiation pressure can be ascribed to photon momentum, which does not exist for longitudinal fields. Two major consequences are that the near-universal acceptance of a static electric field as the zero frequency limit of a laser field is not correct; and that the numerical solution of the dipole-approximate Schr\\"{o}dinger equation for laser effects is inapplicable as the frequency declines. These problems occur because the magnetic component of the laser field is very important at low frequencies, and hence the dipole approximation is not valid. Some experiments already exist that demonstrate the failure of tunneling concepts at low frequencies.

  13. Magnetotransport in MgO-based magnetic tunnel junctions grown by molecular beam epitaxy (invited)

    SciTech Connect (OSTI)

    Andrieu, S., E-mail: stephane.andrieu@univ-lorraine.fr; Bonell, F.; Hauet, T.; Montaigne, F. [Institut Jean Lamour, Nancy University/CNRS, Bd des Aiguillettes, BP239, 54506 Vandoeuvre-lès-Nancy (France); Calmels, L.; Snoeck, E. [CEMES, CNRS and Toulouse University, 29 rue Jeanne Marvig, 31055 Toulouse (France); Lefevre, P.; Bertran, F. [Synchrotron SOLEIL-CNRS, L'Orme des Merisiers, Saint-Aubin, BP48, 91192 Gif-sur-Yvette cedex (France)

    2014-05-07T23:59:59.000Z

    The strong impact of molecular beam epitaxy growth and Synchrotron Radiation characterization tools in the understanding of fundamental issues in nanomagnetism and spintronics is illustrated through the example of fully epitaxial MgO-based Magnetic Tunnel Junctions (MTJs). If ab initio calculations predict very high tunnel magnetoresistance (TMR) in such devices, some discrepancy between theory and experiments still exists. The influence of imperfections in real systems has thus to be considered like surface contaminations, structural defects, unexpected electronic states, etc. The influence of possible oxygen contamination at the Fe/MgO(001) interface is thus studied, and is shown to be not so detrimental to TMR as predicted by ab initio calculations. On the contrary, the decrease of dislocations density in the MgO barrier of MTJs using Fe{sub 1?x}V{sub x} electrodes is shown to significantly increase TMR. Finally, unexpected transport properties in Fe{sub 1?X}Co{sub x}/MgO/Fe{sub 1?X}Co{sub x} (001) are presented. With the help of spin and symmetry resolved photoemission and ab initio calculation, the TMR decrease for Co content higher than 25% is shown to come from the existence of an interface state and the shift of the empty ?1 minority spin state towards the Fermi level.

  14. Postdoc Appointment Types

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible forPortsmouth/Paducah Project Office Press ReleasesPost-Closure BenefitsAppointment Types

  15. Rappels: 4) Piles Types abstraits de donnes (Abstract Data Type)

    E-Print Network [OSTI]

    Hamel, Sylvie

    Rappels: 4) Piles Types abstraits de données (Abstract Data Type) IFT2015, A2009, Sylvie Hamel Université de Montréal 1Piles Type de données Un ensemble de valeurs Un ensemble d'opérations Structure de Université de Montréal 2Piles Type abstrait de données PILE (§4.2) Garde en mémoire des objets arbitraires

  16. InGaN/GaN tunnel junctions for hole injection in GaN light emitting diodes

    SciTech Connect (OSTI)

    Krishnamoorthy, Sriram, E-mail: krishnamoorthy.13@osu.edu, E-mail: rajan@ece.osu.edu; Akyol, Fatih [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Rajan, Siddharth, E-mail: krishnamoorthy.13@osu.edu, E-mail: rajan@ece.osu.edu [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)

    2014-10-06T23:59:59.000Z

    InGaN/GaN tunnel junction contacts were grown using plasma assisted molecular beam epitaxy (MBE) on top of a metal-organic chemical vapor deposition (MOCVD)-grown InGaN/GaN blue (450?nm) light emitting diode. A voltage drop of 5.3?V at 100?mA, forward resistance of 2 × 10{sup ?2} ? cm{sup 2}, and a higher light output power compared to the reference light emitting diodes (LED) with semi-transparent p-contacts were measured in the tunnel junction LED (TJLED). A forward resistance of 5?×?10{sup ?4} ? cm{sup 2} was measured in a GaN PN junction with the identical tunnel junction contact as the TJLED, grown completely by MBE. The depletion region due to the impurities at the regrowth interface between the MBE tunnel junction and the MOCVD-grown LED was hence found to limit the forward resistance measured in the TJLED.

  17. Direct observation of electron emission from the grain boundaries of chemical vapour deposition diamond films by tunneling atomic force microscopy

    E-Print Network [OSTI]

    Bristol, University of

    .1063/1.3475506 Direct observation of electron emission site on boron-doped polycrystalline diamond thin films using or energy harvesting devices. Electron emission studies usually use doped polycrystalline diamond films observation of the emission sites over a large area of polycrystalline diamond using tunneling atomic force

  18. A seasonal high tunnel is a temporary plastic supported structure, at least 6 feet in height, which modifies the cli-

    E-Print Network [OSTI]

    Netoff, Theoden

    resource concerns on private lands with structural and management conservation practices. Applications natural resource benefits from using tunnel struc- tures could include (1) improved plant quality, (2) improved soil quality, and (3) improved water quality through meth- ods such as reduced nutrient

  19. GaN(0001) Surface Structures Studied Using Scanning Tunneling Microscopy and First-Principles Total Energy Calculations

    E-Print Network [OSTI]

    occurring on the (0001) surface of wurtzite GaN are studied using scanning tunneling microscopy, electron and electronic properties of wurtzite GaN surfaces. Several prior studies have reported that these surfaces do reconstructions were identified, corresponding to the two inequivalent polar fac- es of wurtzite GaN, the (0001

  20. Wurtzite GaN surface structures studied by scanning tunneling microscopy and reflection high energy electron diffraction

    E-Print Network [OSTI]

    Wurtzite GaN surface structures studied by scanning tunneling microscopy and reflection high energy-face of wurtzite GaN films grown using molecular beam epitaxy. N-face reconstructions are primarily adatom numerous surface studies of wurtzite GaN have been performed, progress in determining the true surface

  1. Low Speed Virtual Wind Tunnel Simulation For Educational Studies In Introducing Computational Fluid Dynamics And Flow Visualization

    E-Print Network [OSTI]

    Yang, Cher-Chiang

    2008-05-05T23:59:59.000Z

    ............................................................................................................... 25 3.2.4. Starting FlowLab ...................................................................................................................... 26 3.2.5. Geometry Settings... OF THE PROGRAMMING....................................................................... 52 v List of Figures FIGURE 2.1 ? COST AND TIME RELATIONSHIP WITH RESPECT TO CFD AND WIND TUNNELS............................. 5 FIGURE 2.2 - BOEING 777 DESIGN...

  2. Patient-specific hemodynamic performance of Fontan conversion templates: Lateral tunnel vs. intra-atrial with fenestration

    E-Print Network [OSTI]

    Pekkan, Kerem

    . Results: Power loss inside the lateral tunnel Fontan appeared significantly higher than the intra-averaged power loss for both Fontan connections. Flow-structures within the intra-atrial conduit were notability connections: LT-to-IAC Fontan conversion resulted better hemodynamics with less power loss, pressure gradient

  3. Efficient 3D numerical prediction of the pressure wave generated by high-speed trains entering tunnels

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Efficient 3D numerical prediction of the pressure wave generated by high-speed trains entering in a tunnel. The movement of the train is made thanks to a technique of sliding meshes and a conservative-dimensional simulation, Cartesian mesh, Sliding grid, Non-reflecting boundary conditions, High-speed trains. 1

  4. The AFM was originally developed as an adaptation of another scanning probe microscopy technology, the scanning tunneling

    E-Print Network [OSTI]

    Van Vliet, Krystyn J.

    The AFM was originally developed as an adaptation of another scanning probe microscopy technology, the scanning tunneling microscope, to image nonconductive materials through direct physical contact between-scale displacement resolutions of the AFM enable the topographical scanning of mechanically compliant materials

  5. Graphene on Ru(0001) Moire Corrugation Studied by Scanning Tunneling Microscopy on Au/Graphene/Ru(0001) Heterostructures

    E-Print Network [OSTI]

    Ciobanu, Cristian

    Graphene on Ru(0001) Moire Corrugation Studied by Scanning Tunneling Microscopy on Au/Graphene on graphene/Ru(0001) were used to study the corrugation of the moire structure of graphene/Ru(0001 for the graphene/Ru(0001) moire is of structural nature rather than electronic. STM showed a large value

  6. J. CHEM. FARADAY TRANS., 1994, 90(12), 1715-1725 1715 Variational Transition-state Theory and Semiclassical Tunnelling

    E-Print Network [OSTI]

    Truhlar, Donald G

    calculations to the reaction path or swath. An alter- native is the direct dynamics method in which electronic and Semiclassical Tunnelling Calculations with Interpolated Corrections:A New Approach to Interfacing Electronic,H +CD, reactions are included. 1. Introduction The progress of electronic structure theory in providing

  7. Boundary-Layer Stability and Transition on a Flared Cone in a Mach 6 Quiet Wind Tunnel

    E-Print Network [OSTI]

    Hofferth, Jerrod William

    2013-05-15T23:59:59.000Z

    , but experiments relevant to flight require ground-test facilities with very low disturbance levels. To enable this work, a unique Mach 6 low-disturbance wind tunnel, previously of NASA Langley Research Center, is established within a new pressure-vacuum blow...

  8. Scanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Epitaxy

    E-Print Network [OSTI]

    on sapphire substrate [2]. Park et al. performed the growth of Cr doped GaN single crystal by sodium fluxScanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Orleans, New Orleans, LA 70148, USA Abstract: Cr doped GaN was grown by rf N-plasma molecular beam epitaxy

  9. Scanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Epitaxy

    E-Print Network [OSTI]

    doped MOCVD grown GaN on sapphire substrate [2]. Park et al. performed the growth of Cr doped GaN singleScanning Tunneling Microscopy Study of Cr-doped GaN Surface Grown by RF Plasma Molecular Beam Orleans, New Orleans, LA 70148, USA Abstract: Cr doped GaN was grown by rf N-plasma molecular beam epitaxy

  10. THE JOURNAL OF CHEMICAL PHYSICS 139, 244307 (2013) Electron tunneling characteristics of a cubic quantum dot, (PbS)32

    E-Print Network [OSTI]

    Pandey, Ravi

    distribution at the Fermi level seem to determine the tunneling characteristics of the system. © 2013 AIP been of a special interest due to their potential applications in IR photo-detection, photovoltaics-gap controlled PbS nanocrystals of various sizes were synthesized to study the effect of band- gap energy

  11. Concept tests: Wind tunnel tests in controlled wind Comparison tests: Free field comparison to 3D sonic anemometer

    E-Print Network [OSTI]

    comparable potential. Wind measurements on wind turbines in undisturbed wind, relative to nacelle anemometryConcept tests: Wind tunnel tests in controlled wind Comparison tests: Free field comparison to 3D" by CFD calculations Spinner AnemometrySpinner Anemometry -- An Innovative Wind Measurement Concept

  12. Atomic-resolution study of Mn tetramer clusters using scanning tunneling Rong Yang, Haiqiang Yang, and Arthur R. Smitha

    E-Print Network [OSTI]

    Atomic-resolution study of Mn tetramer clusters using scanning tunneling microscopy Rong Yang clusters is investigated. The clusters are composed of a quadrant array of Mn atoms forming a tetramer of manganese nitride, on which are stabilized peri- odic, self-organized array of MnN-bonded Mn tetramer clus

  13. Tunnel-injection quantum dot deep-ultraviolet light-emitting diodes with polarization-induced doping in III-nitride heterostructures

    SciTech Connect (OSTI)

    Verma, Jai, E-mail: jverma@nd.edu; Islam, S. M.; Protasenko, Vladimir; Kumar Kandaswamy, Prem; Xing, Huili; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

    2014-01-13T23:59:59.000Z

    Efficient semiconductor optical emitters in the deep-ultraviolet spectral window are encountering some of the most deep rooted problems of semiconductor physics. In III-Nitride heterostructures, obtaining short-wavelength photon emission requires the use of wide bandgap high Al composition AlGaN active regions. High conductivity electron (n-) and hole (p-) injection layers of even higher bandgaps are necessary for electrical carrier injection. This approach requires the activation of very deep dopants in very wide bandgap semiconductors, which is a difficult task. In this work, an approach is proposed and experimentally demonstrated to counter the challenges. The active region of the heterostructure light emitting diode uses ultrasmall epitaxially grown GaN quantum dots. Remarkably, the optical emission energy from GaN is pushed from 365?nm (3.4?eV, the bulk bandgap) to below 240?nm (>5.2?eV) because of extreme quantum confinement in the dots. This is possible because of the peculiar bandstructure and band alignments in the GaN/AlN system. This active region design crucially enables two further innovations for efficient carrier injection: Tunnel injection of carriers and polarization-induced p-type doping. The combination of these three advances results in major boosts in electroluminescence in deep-ultraviolet light emitting diodes and lays the groundwork for electrically pumped short-wavelength lasers.

  14. Electrical spin injection into InGaAs/GaAs quantum wells: A comparison between MgO tunnel barriers grown by sputtering and molecular beam epitaxy methods

    SciTech Connect (OSTI)

    Barate, P.; Zhang, T. T.; Vidal, M.; Renucci, P.; Marie, X.; Amand, T. [Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 avenue de Rangueil, 31077 Toulouse (France); Liang, S.; Devaux, X.; Hehn, M.; Mangin, S.; Lu, Y., E-mail: yuan.lu@univ-lorraine.fr [Institut Jean Lamour, UMR 7198, CNRS-Nancy Université, BP 239, 54506 Vandoeuvre (France); Frougier, J.; Jaffrès, H.; George, J. M. [Unité Mixte de Physique CNRS/Thales and Université Paris-Sud 11, 1 avenue A. Fresnel, 91767 Palaiseau (France); Xu, B.; Wang, Z. [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing 100083 (China); Zheng, Y. [Institut des NanoSciences de Paris, UPMC, CNRS UMR 7588, 4 place Jussieu, 75005 Paris (France); Tao, B. [Institut Jean Lamour, UMR 7198, CNRS-Nancy Université, BP 239, 54506 Vandoeuvre (France); Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190 (China); Han, X. F. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190 (China)

    2014-07-07T23:59:59.000Z

    An efficient electrical spin injection into an InGaAs/GaAs quantum well light emitting diode is demonstrated thanks to a CoFeB/MgO spin injector. The textured MgO tunnel barrier is fabricated by two different techniques: sputtering and molecular beam epitaxy. The maximal spin injection efficiency is comparable for both methods. Additionally, the effect of annealing is also investigated for the two types of samples. Both samples show the same trend: an increase of the electroluminescence circular polarization (P{sub c}) with the increase of annealing temperature, followed by a saturation of P{sub c} beyond 350?°C annealing. Since the increase of P{sub c} starts well below the crystallization temperature of the full CoFeB bulk layer, this trend could be mainly due to an improvement of chemical structure at the top CoFeB/MgO interface. This study reveals that the control of CoFeB/MgO interface is essential for an optimal spin injection into semiconductor.

  15. Health and safety evaluation of a modified tunnel-borer design for application to single-entry coal-mine development

    SciTech Connect (OSTI)

    Zimmerman, W. F.

    1982-02-15T23:59:59.000Z

    The health and safety analysis is part of an overall effort to identify and develop innovative underground coal extraction systems. The single-entry tunnel borer system was initially considered an innovative approach to underground mining because it exhibited a means of increasing the speed and efficiency of entry development by reducing the number of entries. However, to be considered a truly advanced system, the tunnel borer had to meet distinct safety criteria as well. The objective was to examine the tunnel borer design and determine whether it offset major health hazards, and satisfied the prescribed safety levels. As a baseline for comparison, the tunnel borer was compared against the continuous mining entry driving system. The results of the health analysis indicated that while the tunnel borer design offered improvements in dust control through the use of water sprays, a higher face ventilation rate, and the application of spalling rather than the conventional grinding process, it interjected an additional mutagenic is and toxic compound into the environment through the use of shotcrete. The tunnel borer system easily conformed with the prescribed fatality limit, but exceeded the required limits for disabling and overall injuries. It also exhibited projected disabling and overall injury rates considerably higher than existing continuous mining injury rates. Consequently, the tunnel borer system was not considered an advanced system.

  16. Evaluate and characterize mechanisms controlling transport, fate and effects of army smokes in an aerosol wind tunnel: Transport, transformations, fate and terrestrial ecological effects of fog oil obscurant smokes: Final report

    SciTech Connect (OSTI)

    Cataldo, D.A.; Van Voris, P.; Ligotke, M.W.; Fellows, R.J.; McVeety, B.D.; Li, Shu-mei W.; Bolton, H. Jr.; Fredrickson, J.K.

    1989-01-01T23:59:59.000Z

    The terrestrial transport, chemical fate, and ecological effects of fog oil (FO) smoke obscurants were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on an exposure scenario, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of fog oil smoke/obscurants is establishing the importance of environmental parameters, such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and three soil types. 29 refs., 35 figs., 32 tabs.

  17. Mechanism design with approximate types

    E-Print Network [OSTI]

    Zhu, Zeyuan Allen

    2012-01-01T23:59:59.000Z

    In mechanism design, we replace the strong assumption that each player knows his own payoff type exactly with the more realistic assumption that he knows it only approximately: each player i only knows that his true type ...

  18. Types of Farming in Texas.

    E-Print Network [OSTI]

    Bonnen, C. A.

    1960-01-01T23:59:59.000Z

    .......... .......-.----------------------. 8 Labor -..-.....-----...------------------------------------------------. 9 Land Tenure .--.----....---....--------------------------------- 9 Number and Size of Farms ....----...----.-._--------- 10 Capital... -------------...-------.---------------------------- 21 Hogs -......-....--------------------------------------------------- 22 Poultry .-.---.-.....--.-..------.---------------------------------- 22 Horses and Mules ---..-....---..--..------------------------ 23 Types of Farming and Type-of-farming...

  19. Bichromatic control of dynamical tunneling: influence of the irregular Floquet states

    E-Print Network [OSTI]

    Archana Shukla; Srihari Keshavamurthy

    2014-11-27T23:59:59.000Z

    Bichromatic control, in terms of the amplitude and relative phase of the second field as control knobs, is an useful approach for controlling a variety of quantum processes. In this context, understanding the features of the control landscape is important to assess the extent and efficiency of the control process. A key question is whether, for a given quantum process, one can have regions wherein there is a complete lack of control. In this work we show that such regions do exist and can be explained on the basis of the phase space nature of the quantum Floquet states. Specifically, we show that robust regions of no control arise due to the phenomenon of chaos-assisted tunneling. We also comment on the possible influence of such regions on the phenomenon of directed transport in quantum Hamiltonian ratchets.

  20. Method and apparatus for differential spectroscopic atomic-imaging using scanning tunneling microscopy

    DOE Patents [OSTI]

    Kazmerski, Lawrence L. (Lakewood, CO)

    1990-01-01T23:59:59.000Z

    A Method and apparatus for differential spectroscopic atomic-imaging is disclosed for spatial resolution and imaging for display not only individual atoms on a sample surface, but also bonding and the specific atomic species in such bond. The apparatus includes a scanning tunneling microscope (STM) that is modified to include photon biasing, preferably a tuneable laser, modulating electronic surface biasing for the sample, and temperature biasing, preferably a vibration-free refrigerated sample mounting stage. Computer control and data processing and visual display components are also included. The method includes modulating the electronic bias voltage with and without selected photon wavelengths and frequency biasing under a stabilizing (usually cold) bias temperature to detect bonding and specific atomic species in the bonds as the STM rasters the sample. This data is processed along with atomic spatial topography data obtained from the STM raster scan to create a real-time visual image of the atoms on the sample surface.

  1. In situ scanning tunneling microscope tip treatment device for spin polarization imaging

    DOE Patents [OSTI]

    Li, An-Ping [Oak Ridge, TN; Jianxing, Ma [Oak Ridge, TN; Shen, Jian [Knoxville, TN

    2008-04-22T23:59:59.000Z

    A tip treatment device for use in an ultrahigh vacuum in situ scanning tunneling microscope (STM). The device provides spin polarization functionality to new or existing variable temperature STM systems. The tip treatment device readily converts a conventional STM to a spin-polarized tip, and thereby converts a standard STM system into a spin-polarized STM system. The tip treatment device also has functions of tip cleaning and tip flashing a STM tip to high temperature (>2000.degree. C.) in an extremely localized fashion. Tip coating functions can also be carried out, providing the tip sharp end with monolayers of coating materials including magnetic films. The device is also fully compatible with ultrahigh vacuum sample transfer setups.

  2. Three-terminal magnetic tunneling junction device with perpendicular anisotropy CoFeB sensing layer

    SciTech Connect (OSTI)

    Honjo, H., E-mail: hr-honjou@aist.go.jp; Nebashi, R.; Tokutome, K.; Miura, S.; Sakimura, N.; Sugibayashi, T. [Green Platform Research Laboratories, NEC Corporation, Tsukuba (Japan); Fukami, S.; Kinoshita, K.; Murahata, M.; Kasai, N. [Center for Spintronics Integrated Systems, Tohoku University, Sendai (Japan); Ishihara, K. [Smart Energy Research Laboratories, NEC Corporation, Tsukuba (Japan); Ohno, H. [Center for Spintronics Integrated Systems, Tohoku University, Sendai (Japan); Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai (Japan); WPI Advanced Institute for Materials Research, Tohoku University, Sendai (Japan)

    2014-05-07T23:59:59.000Z

    We demonstrated read and write characteristics of a three terminal memory device with a perpendicular anisotropy-free layer of a strip of [Co/Ni] and a low-switching perpendicular-anisotropy CoFeB/MgO sensing layer. This new design of the cell results in a small cell area. The switching magnetic field of the sensing layer can be decreased by changing sputtering gas for the Ta-cap from Ar to Kr. An electron energy-loss spectroscopy analysis of the cross-section of the magnetic tunneling junction (MTJ) revealed that the boron content in CoFeB with a Kr-sputtered Ta-cap was smaller than that with an Ar-sputtered one. A change in resistance for the MTJ was observed that corresponded to the magnetic switching of the Co/Ni wire and its magnetoresistance ratio and critical current were 90% and 0.8?mA, respectively.

  3. Evidence of impurity assisted tunneling in SiGe/Si heterostructures

    SciTech Connect (OSTI)

    Zhukavin, R. Kh.; Bekin, N. A.; Lobanov, D. N.; Drozdov, M. N.; Drozdov, Yu. N.; Kozlov, D. V.; Pryakhin, D. A.; Shastin, V. N. [Institute for Physics of Microstructures RAS, 603950, Nizhny Novgorod, GSP-105 (Russian Federation); Shengurov, V. G. [Nizhny Novgorod State University, 603950, Nizhny Novgorod, Gagarina avenue, 23 (Russian Federation)

    2013-12-04T23:59:59.000Z

    The investigation of vertical transport in delta-doped SiGe/Si heterostructures has been presented. The asymmetrical triple barrier structure was grown by MBE technique. The delta layer of boron impurity was placed into the center of narrower quantum well. The growth procedure was followed by conventional processing including photolithography and plasma etching and magnetron sputtering. SIMS and X-rays diagnostics have been used to control the desired structure. The conductance of the structure has been measured at liquid helium temperature and analyzed. All pronounced resonances have been identified. The resonant feature near 60 mV has to be attributed to impurity-assisted tunneling that is supported by calculation of binding energy of the acceptor in the narrower quantum well.

  4. Tornado type wind turbines

    DOE Patents [OSTI]

    Hsu, Cheng-Ting (Ames, IA)

    1984-01-01T23:59:59.000Z

    A tornado type wind turbine has a vertically disposed wind collecting tower with spaced apart inner and outer walls and a central bore. The upper end of the tower is open while the lower end of the structure is in communication with a wind intake chamber. An opening in the wind chamber is positioned over a turbine which is in driving communication with an electrical generator. An opening between the inner and outer walls at the lower end of the tower permits radially flowing air to enter the space between the inner and outer walls while a vertically disposed opening in the wind collecting tower permits tangentially flowing air to enter the central bore. A porous portion of the inner wall permits the radially flowing air to interact with the tangentially flowing air so as to create an intensified vortex flow which exits out of the top opening of the tower so as to create a low pressure core and thus draw air through the opening of the wind intake chamber so as to drive the turbine.

  5. Microstructure and conductance-slope of InAs/GaSb tunnel diodes

    SciTech Connect (OSTI)

    Iutzi, Ryan M., E-mail: iutzi@mit.edu; Fitzgerald, Eugene A. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2014-06-21T23:59:59.000Z

    InAs/GaSb and similar materials systems have generated great interest as a heterojunction for tunnel field effect transistors (TFETs) due to favorable band alignment. However, little is currently understood about how such TFETs are affected by materials defects and nonidealities. We present measurements of the conductance slope for various InAs/GaSb heterojunctions via two-terminal electrical measurements, which removes three-terminal parasitics and enables direct study on the effect of microstructure on tunnelling. Using this, we can predict how subthreshold swings in TFETs can depend on microstructure. We also demonstrate growth and electrical characterization for structures grown by metalorganic chemical vapor deposition (MOCVD)—a generally more scalable process compared with molecular beam epitaxy (MBE). We determine that misfit dislocations and point defects near the interface can lead to energy states in the band-gap and local band bending that result in trap-assisted leakage routes and nonuniform band alignment across the junction area that lower the steepness of the conductance slope. Despite the small lattice mismatch, misfit dislocations still form in InAs on GaSb due to relaxation as a result of large strain from intermixed compositions. This can be circumvented by growing GaSb on InAs, straining the GaSb underlayer, or lowering the InAs growth temperature in the region of the interface. The conductance slope can also be improved by annealing the samples at higher temperatures, which we believe acts to annihilate point defects and average out major fluctuations in band alignment across the interface. Using a combination of these techniques, we can greatly improve the steepness of the conductance slope which could result in steeper subthreshold swings in TFETs in the future.

  6. On the valve nature of a monolayer of aligned molecular magnets in tunneling spin-polarized electrons: Towards organic molecular spintronics

    SciTech Connect (OSTI)

    Chakrabarti, Sudipto; Pal, Amlan J., E-mail: sspajp@iacs.res.in [Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

    2014-01-06T23:59:59.000Z

    We form a monolayer of magnetic organic molecules and immobilize their moments pointing either upwards or downwards with respect to the substrate through an electrostatic-binding process. Such a monolayer is probed with a scanning tunneling microscope tip, which is also magnetized with the magnetization vector pointing towards (or away from) apex of the tip. From spin-polarized tunneling current, we show that the current was higher when magnetization vectors of the tip and molecules were parallel as compared to that when they were anti-parallel. We show that for tunneling of spin-polarized electrons, aligned organic molecular magnets can act as a valve.

  7. A dependent nominal type theory

    E-Print Network [OSTI]

    Cheney, James

    2012-01-01T23:59:59.000Z

    Nominal abstract syntax is an approach to representing names and binding pioneered by Gabbay and Pitts. So far nominal techniques have mostly been studied using classical logic or model theory, not type theory. Nominal extensions to simple, dependent and ML-like polymorphic languages have been studied, but decidability and normalization results have only been established for simple nominal type theories. We present a LF-style dependent type theory extended with name-abstraction types, prove soundness and decidability of beta-eta-equivalence checking, discuss adequacy and canonical forms via an example, and discuss extensions such as dependently-typed recursion and induction principles.

  8. On the asymptotic homotopy type of inductive limit Type ...

    E-Print Network [OSTI]

    In this note we exhibit large classes of (projeetionless) stable, nuclear C*- algebras whose asymptotic homotopy type is determined by K-theoretical data.

  9. Danger of Tunnels on Al Aqsa Mosque Buildings For more than 40 years, the city of Jerusalem has faced accelerated historical transformation on

    E-Print Network [OSTI]

    Danger of Tunnels on Al Aqsa Mosque Buildings Abstract For more than 40 years, the city Aqsa Mosque, with the objective to pursue its dangerous influence on the structure of Islamic buildings

  10. Comment on: Direct space-time observation of pulse tunneling in an electromagnetic band gap, S.Doiron,A.Hache,H.Winful

    E-Print Network [OSTI]

    G. Nimtz; A. A. Stahlhofen

    2007-10-26T23:59:59.000Z

    The title of this article is misleading. The authors have investigated a resonator but not a tunneling barrier see also Refs.\\cite{Winful2} The measured superluminal group velocity and discussed is that studied on a Lorentz-Lorenz oscillator by Sommerfeld and Brillouin a hundred years ago \\cite{Brillouin}. It is similar to the faster than light experiment by Wang et al. based also on anomalous dispersion with a complex refractive index of a resonator \\cite{Wang}. Tunneling, however, is understood and performed by electromagnetic evanescent modes or by tunneling solutions of the Schr\\"odinger equation, which have purely imaginary wave numbers. The latter includes a purely imaginary refractive index. Signals with purely evanescent frequency components can travel at a superluminal velocity \\cite{NimtzH,Nimtz1}. Inside the barrier tunneling proceeds even instantaneously, i.e.by a process described by virtual photons \\cite{Stahlhofen}.

  11. Type of Space Bulb Type #/House Fixture Style Greenhouse #

    E-Print Network [OSTI]

    Pawlowski, Wojtek

    Type of Space Bulb Type #/House Fixture Style Greenhouse # 1 Lu 430/Lu 400 24 White box style 2 Lu No bulbs 0 N/A Seed harvest room F32 T8/TL 841 90 bulbs VIGS Room F032 /741/ECO 60 bulbs Chamber Model Bulb

  12. A new InGaP/GaAs tunneling heterostructure-emitter bipolar transistor (T-HEBT)

    SciTech Connect (OSTI)

    Tsai, Jung-Hui, E-mail: jhtsai@nknucc.nknu.edu.tw [National Kaohsiung Normal University, Department of Electronic Engineering, Taiwan (China); Lee, Ching-Sung [Feng Chia University, Department of Electronic Engineering, Taiwan (China); Lour, Wen-Shiung [National Taiwan Ocean University, Department of Electrical Engineering, Taiwan (China); Ma, Yung-Chun; Ye, Sheng-Shiun [National Kaohsiung Normal University, Department of Electronic Engineering, Taiwan (China)

    2011-05-15T23:59:59.000Z

    Excellent characteristics of an InGaP/GaAs tunneling heterostructure-emitter bipolar transistor (T-HEBT) are first demonstrated. The insertion of a thin n-GaAs emitter layer between tynneling confinement and base layers effectivelty eliminates the potential spike at base-emitter junction and reduces the collector-emitter offset voltage, while the thin InGaP tunneling confinement layer is employed to reduce the transporting time across emitter region for electrons and maintain the good confinement effect for holes. Experimentally, the studied T-HEBN exhibits a maximum current gain of 285, a relatively low offset voltage of 40 mW, and a current-gain cutoff frequency of 26.4 GHz.

  13. Constraining the Natural MSSM through tunneling to color-breaking vacua at zero and non-zero temperature

    E-Print Network [OSTI]

    J. E. Camargo-Molina; B. Garbrecht; B. O'Leary; W. Porod; F. Staub

    2014-09-01T23:59:59.000Z

    We re-evaluate the constraints on the parameter space of the minimal supersymmetric standard model from tunneling to charge- and/or color-breaking minima, taking into account thermal corrections. We pay particular attention to the region known as the Natural MSSM, where the masses of the scalar partners of the top quarks are within an order of magnitude or so of the electroweak scale. These constraints arise from the interaction between these scalar tops and the Higgs fields, which allows the possibility of parameter points having deep charge- and color-breaking true vacua. In addition to requiring that our electro-weak-symmetry-breaking, yet QCD- and electromagnetism-preserving vacuum has a sufficiently long lifetime at zero temperature, also demanding stability against thermal tunneling further restricts the allowed parameter space.

  14. Methane dissociative chemisorption and detailed balance on Pt(111): Dynamical constraints and the modest influence of tunneling

    SciTech Connect (OSTI)

    Donald, S. B.; Navin, J. K.; Harrison, I., E-mail: harrison@virginia.edu [Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319 (United States)

    2013-12-07T23:59:59.000Z

    A dynamically biased (d-) precursor mediated microcanonical trapping (PMMT) model of the activated dissociative chemisorption of methane on Pt(111) is applied to a wide range of dissociative sticking experiments, and, by detailed balance, to the methane product state distributions from the thermal associative desorption of adsorbed hydrogen with coadsorbed methyl radicals. Tunneling pathways were incorporated into the d-PMMT model to better replicate the translational energy distribution of the desorbing methane product from the laser induced thermal reaction of coadsorbed hydrogen and methyl radicals occurring near T{sub s} = 395 K. Although tunneling is predicted to be inconsequential to the thermal dissociative chemisorption of CH{sub 4} on Pt(111) at the high temperatures of catalytic interest, once the temperature drops to 395 K the tunneling fraction of the reactive thermal flux reaches 15%, and as temperatures drop below 275 K the tunneling fraction exceeds 50%. The d-PMMT model parameters of (E{sub 0} = 58.9?kJ/mol,?s = 2,??{sub v} = 0.40) describe the apparent threshold energy for CH{sub 4}/Pt(111) dissociative chemisorption, the number of surface oscillators involved in the precursor complex, and the efficacy of molecular vibrational energy to promote reaction, relative to translational energy directed along the surface normal. Molecular translations parallel to the surface and rotations are treated as spectator degrees of freedom. Transition state vibrational frequencies are derived from generalized gradient approximation-density functional theory electronic structure calculations. The d-PMMT model replicates the diverse range of experimental data available with good fidelity, including some new effusive molecular beam and ambient gas dissociative sticking measurements. Nevertheless, there are some indications that closer agreement between theory and experiments could be achieved if a surface efficacy less than one was introduced into the modeling as an additional dynamical constraint.

  15. Design of a high angle of attack robotic sting mount for tests in a low speed wind tunnel

    E-Print Network [OSTI]

    Kubler, Tommy Jack

    1989-01-01T23:59:59.000Z

    Page INTRODUCTION, . DESIGN DEVELOPMENT . . Tunnel Environment Preliminary Concepts Concept Development . . Preliminary Sizing . Aerodynamic Load Estimation Strut Sizing Wear Pad Design Fasteners . Drive Mechanism Drive Screws Motor... of TAMU LSWT small Langley sting. 20 15 Strut casing spacial restrictions. 21 16 Lower strut casing-to-casing clearance. 22 17 Simplified aircraft shape 18 Oblique view of front strut extension pivot joint. 19 Typical wear pad design 29 20 General...

  16. Entropy is conserved in Hawking radiation as tunneling: A revisit of the black hole information loss paradox

    SciTech Connect (OSTI)

    Zhang Baocheng [State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Cai Qingyu, E-mail: qycai@wipm.ac.cn [State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Zhan Mingsheng [State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071 (China); You Li [Department of Physics, Tsinghua University, Beijing 100084 (China)

    2011-02-15T23:59:59.000Z

    Research Highlights: > Information is found to be encoded and carried away by Hawking radiations. > Entropy is conserved in Hawking radiation. > We thus conclude no information is lost. > The dynamics of black hole may be unitary. - Abstract: We revisit in detail the paradox of black hole information loss due to Hawking radiation as tunneling. We compute the amount of information encoded in correlations among Hawking radiations for a variety of black holes, including the Schwarzchild black hole, the Reissner-Nordstroem black hole, the Kerr black hole, and the Kerr-Newman black hole. The special case of tunneling through a quantum horizon is also considered. Within a phenomenological treatment based on the accepted emission probability spectrum from a black hole, we find that information is leaked out hidden in the correlations of Hawking radiation. The recovery of this previously unaccounted for information helps to conserve the total entropy of a system composed of a black hole plus its radiations. We thus conclude, irrespective of the microscopic picture for black hole collapsing, the associated radiation process: Hawking radiation as tunneling, is consistent with unitarity as required by quantum mechanics.

  17. Resistive switching of a TaO{sub x}/TaON double layer via ionic control of carrier tunneling

    SciTech Connect (OSTI)

    Jeon, Heeyoung; Park, Jingyu; Kim, Hyunjung [Department of Nano-Scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Jang, Woochool; Song, Hyoseok [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Kang, Chunho [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); FAB Manufacturing Division, SK Hynix Inc., 2091, Gyeongchung-daero, Bubal-eub, Icheon-si, Gyeonggi-do 167-701 (Korea, Republic of); Seo, Hyungtak, E-mail: hseo@ajou.ac.kr [Department of Materials Science and Engineering and Department of Energy Systems Research, Ajou University, Suwon 443-739 (Korea, Republic of); Jeon, Hyeongtag, E-mail: hjeon@hanyang.ac.kr [Department of Nano-Scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2014-04-14T23:59:59.000Z

    Resistance random access memory (RRAM) is an attractive candidate for future non-volatile memory due to its superior features. As the oxide thickness is scaled down, the charge transport mechanism is also subject to the transition from hopping to tunneling dominant process, which is critically related to the interfacial electronic band structure. A TaO{sub x}/TaON double layer-based RRAM is fabricated and characterized in this work. Upon TaON insertion at the lower interface, the improved switching behavior is observed. The TaON at the bottom electrode interface blocks oxygen vacancy percolation due to strong N-O bonds and also modifies interfacial band alignment to lower the injected electron energy from bottom electrode due to higher tunneling barrier height than that of TaO{sub x}/Pt. This study suggested that a defect-minimized insertion layer like TaON with a proper interfacial band alignment is pivotal in RRAM for the effective ionic control of carrier tunneling resulting in non-linear I-V behavior with improved properties.

  18. New approaches for modeling type Ia supernovae

    E-Print Network [OSTI]

    Zingale, Michael; Almgren, Ann S.; Bell, John B.; Day, Marcus S.; Rendleman, Charles A.; Woosley, Stan

    2007-01-01T23:59:59.000Z

    runaway in Type Ia supernovae: How to run away? oIgnition in Type Ia Supernovae. II. A Three- dimensionalnumber modeling of type Ia supernovae. I. hydrodynamics.

  19. Design, fabrication, and analysis of p-channel arsenide/antimonide hetero-junction tunnel transistors

    SciTech Connect (OSTI)

    Rajamohanan, Bijesh, E-mail: bor5067@psu.edu; Mohata, Dheeraj; Hollander, Matthew; Datta, Suman [Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Zhu, Yan; Hudait, Mantu [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Jiang, Zhengping; Klimeck, Gerhard [Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47906 (United States)

    2014-01-28T23:59:59.000Z

    In this paper, we demonstrate InAs/GaSb hetero-junction (hetJ) and GaSb homo-junction (homJ) p-channel tunneling field effect transistors (pTFET) employing a low temperature atomic layer deposited high-? gate dielectric. HetJ pTFET exhibited drive current of 35 ?A/?m in comparison to homJ pTFET, which exhibited drive current of 0.3 ?A/?m at V{sub DS}?=??0.5?V under DC biasing conditions. Additionally, with pulsing of 1 ?s gate voltage, hetJ pTFET exhibited enhanced drive current of 85 ?A/?m at V{sub DS}?=??0.5?V, which is the highest reported in the category of III-V pTFET. Detailed device characterization was performed through analysis of the capacitance-voltage characteristics, pulsed current-voltage characteristics, and x-ray diffraction studies.

  20. YUCCA MOUNTAIN SITE CHARACTERIZATIONS PROJECT TUNNEL BORING MACHINE (TBM) SYSTEM SAFETY ANALYSIS

    SciTech Connect (OSTI)

    N /A

    1997-02-19T23:59:59.000Z

    The purpose of this analysis is to systematically identify and evaluate hazards related to the tunnel boring machine (TBM) used in the Exploratory Studies Facility (ESF) at the Yucca Mountain Site Characterization Project. This process is an integral part of the systems engineering process; whereby safety is considered during planning, design, testing, and construction. Since the TBM is an ''as built'' system, the M&O is conducting the System Safety Analysis during the construction or assembly phase of the TBM. A largely qualitative approach was used since a radiological System Safety Analysis is not required. The risk assessment in this analysis characterizes the accident scenarios associated with the TBM in terms of relative risk and includes recommendations for mitigating all identified risks. The priority for recommending and implementing mitigation control features is: (1) Incorporate measures to reduce risks and hazards into the system/subsystem/component design, (2) add safety features and capabilities to existing designs, and (3) develop procedures and conduct training to increase worker awareness of potential hazards, on methods to reduce exposure to hazards, and on the actions required to avoid accidents or correct hazardous conditions. The scope of this analysis is limited to the TBM during normal operations, excluding hazards occurring during assembly and test of the TBM or maintenance of the TBM equipment.

  1. A 30 mK, 13.5 T scanning tunneling microscope with two independent tips

    SciTech Connect (OSTI)

    Roychowdhury, Anita [Laboratory for Physical Sciences, College Park, Maryland 20742 (United States) [Laboratory for Physical Sciences, College Park, Maryland 20742 (United States); Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20740 (United States); Gubrud, M. A.; Dana, R.; Dreyer, M. [Laboratory for Physical Sciences, College Park, Maryland 20742 (United States)] [Laboratory for Physical Sciences, College Park, Maryland 20742 (United States); Anderson, J. R.; Lobb, C. J.; Wellstood, F. C. [Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20740 (United States)] [Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20740 (United States)

    2014-04-15T23:59:59.000Z

    We describe the design, construction, and performance of an ultra-low temperature, high-field scanning tunneling microscope (STM) with two independent tips. The STM is mounted on a dilution refrigerator and operates at a base temperature of 30 mK with magnetic fields of up to 13.5 T. We focus on the design of the two-tip STM head, as well as the sample transfer mechanism, which allows in situ transfer from an ultra high vacuum preparation chamber while the STM is at 1.5 K. Other design details such as the vibration isolation and rf-filtered wiring are also described. Their effectiveness is demonstrated via spectral current noise characteristics and the root mean square roughness of atomic resolution images. The high-field capability is shown by the magnetic field dependence of the superconducting gap of Cu{sub x}Bi{sub 2}Se{sub 3}. Finally, we present images and spectroscopy taken with superconducting Nb tips with the refrigerator at 35 mK that indicate that the effective temperature of our tips/sample is approximately 184 mK, corresponding to an energy resolution of 16 ?eV.

  2. Phase transitions and vacuum tunneling into charge- and color-breaking minima in the MSSM

    SciTech Connect (OSTI)

    Kusenko, A.; Langacker, P. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396 (United States)] [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396 (United States); [Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States); Segre, G. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396 (United States)] [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396 (United States)

    1996-11-01T23:59:59.000Z

    The scalar potential of the MSSM may have local and global minima characterized by nonzero expectation values of charged and colored bosons. Even if the true vacuum is not color and charge conserving, the early Universe is likely to occupy the minimum of the potential in which only the neutral Higgs fields have nonzero VEV{close_quote}s. The stability of this false vacuum with respect to quantum tunneling imposes important constraints on the values of the MSSM parameters. We analyze these constraints using some novel methods for calculating the false vacuum decay rate. Some regions of the MSSM parameter space are ruled out because the lifetime of the corresponding physically acceptable false vacuum is small in comparison to the present age of the Universe. However, there is a significant fraction of the parameter space that is consistent with the hypothesis that the Universe rests in the false vacuum that is stable on a cosmological time scale. {copyright} {ital 1996 The American Physical Society.}

  3. Field Wind Tunnel Assessment of the Potential for Wind Transport of Soils at Clean Slate 1

    SciTech Connect (OSTI)

    Lancaster, Nicholas [DRI; Gillespie, David [DRI; Hokett, Sam [DRI; Metzger, Steve [DRI

    2005-02-01T23:59:59.000Z

    Field wind tunnel studies conducted in May, June, and November 1997 on the remediated area at Clean Slate 1 provide information on the resuspension of dust from untreated surfaces and those stabilized with the co-polymer "Agrilok". A total of 24 valid datasets were obtained and provide information on the total flux of dust in a "worst case" scenario. The test conducted indicate that the surfaces treated with Agrilok are resistant to erosion and resuspension of fine particles by wind action in all but extreme cases. Most of the material emitted by these surfaces is probably derived from resuspension of dust deposited by natural processes with a minor contribution from disturbance during remediation activities. The concentration of 239Pu in in emitted dust was very low. In combination with the low dust fluxes from the treated surfaces, this resulted in a low activity flux of 239Pu from these surfaces. The results of this study strongly suggest that the techniques for remediating these surfaces are effective in minimizing the flux of dust that may contain 239Pu .

  4. Field Wind Tunnel Assessment of the Potential for Wind Transport of Soils

    SciTech Connect (OSTI)

    Lancaster, Nicholas [Desert Research Inst. (DRI), Reno, NV (United States); Metzger, Steve [Desert Research Inst. (DRI), Reno, NV (United States)

    2005-02-01T23:59:59.000Z

    This report documents a series of field experiments carried out in the Double Tracks area of the Tonopah Test Range in June, July, and August 1996 and March and July 1997. The aim of the experiments was to: (1) determine the wind speeds necessary to entrain surface particles from excavated surfaces in the study area and (2) determine dust emissions from surfaces that had been stabilized permanently by planted natural vegetation. This investigation assessed the potential for wind transport of surface soils, including resuspension and emission of dust sized particles from areas of surface heavy metal contamination, following site remediation, as well as the actual emissions from these areas. The remediation site is located in Area 73 of the Tonopah Test Range. The goal of the field experiments was to measure the velocities with which boundary layer winds might initiate dust emissions from the affected site, and to gage the effectiveness of surface stabilization procedures to prevent such emissions. Particle movement measurements were generated through the use of a portable wind tunnel laid directly on the excavated surface.

  5. Quantum dynamics and macroscopic quantum tunneling of two weakly coupled condensates

    E-Print Network [OSTI]

    René John Kerkdyk; S. Sinha

    2012-09-24T23:59:59.000Z

    We study the quantum dynamics of a Bose Josephson junction(BJJ) made up of two coupled Bose-Einstein condensates. Apart from the usual ac Josephson oscillations, two different dynamical states of BJJ can be observed by tuning the inter-particle interaction strength, which are known as '$\\pi$-oscillation' with relative phase $\\pi$ between the condensates and 'macroscopic self-trapped' (MST) state with finite number imbalance. By choosing appropiate intial state we study above dynamical branches quantum mechanically and compare with classical dynamics. The stability region of the '$\\pi$-oscillation' is separated from that of 'MST' state at a critical coupling strength. Also a significant change in the energy spectrum takes place above the critical coupling strength, and pairs of (quasi)-degenerate excited states appear. The original model of BJJ can be mapped on to a simple Hamiltonian describing quantum particle in an 'effective potential' with an effective Planck constant. Different dynamical states and degenerate excited states in the energy spectrum can be understood in this 'effective potential' approach. Also possible novel quantum phenomena like 'macroscopic quantum tunneling'(MQT) become evident from the simple picture of 'effective potential'. We study decay of metastable '$\\pi$-oscillation' by MQT through potential barrier. The doubly degenerate excited states in the energy spectrum are associated with the classically degenerate MST states with equal and opposite number imbalance. We calculate the energy splitting between these quasi-degenerate excited states due to MQT of the condensate between classically degenerate MST states.

  6. Scanning tunneling microscopy/spectroscopy of picene thin films formed on Ag(111)

    SciTech Connect (OSTI)

    Yoshida, Yasuo, E-mail: yyoshida@issp.u-tokyo.ac.jp; Yokosuka, Takuya; Hasegawa, Yukio, E-mail: hasegawa@issp.u-tokyo.ac.jp [The Institute of Solid State Physics, The University of Tokyo, Kashiwa 277-8581 (Japan); Yang, Hung-Hsiang [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Huang, Hsu-Sheng; Guan, Shu-You; Su, Wei-Bin; Chang, Chia-Seng [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Yanagisawa, Susumu [Department of Physics and Earth Science Department, University of the Ryukyus, 1 Nishihara, Okinawa 903-0213 (Japan); Lin, Minn-Tsong [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China); Hoffmann, Germar [The Institute of Solid State Physics, The University of Tokyo, Kashiwa 277-8581 (Japan); Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2014-09-21T23:59:59.000Z

    Using ultrahigh-vacuum low-temperature scanning tunneling microscopy and spectroscopy combined with first principles density functional theory calculations, we have investigated structural and electronic properties of pristine and potassium (K)-deposited picene thin films formed in situ on a Ag(111) substrate. At low coverages, the molecules are uniformly distributed with the long axis aligned along the [112{sup ¯}] direction of the substrate. At higher coverages, ordered structures composed of monolayer molecules are observed, one of which is a monolayer with tilted and flat-lying molecules resembling a (11{sup ¯}0) plane of the bulk crystalline picene. Between the molecules and the substrate, the van der Waals interaction is dominant with negligible hybridization between their electronic states; a conclusion that contrasts with the chemisorption exhibited by pentacene molecules on the same substrate. We also observed a monolayer picene thin film in which all molecules were standing to form an intermolecular ? stacking. Two-dimensional delocalized electronic states are found on the K-deposited ? stacking structure.

  7. Influence of hydrogen patterning gas on electric and magnetic properties of perpendicular magnetic tunnel junctions

    SciTech Connect (OSTI)

    Jeong, J. H., E-mail: juno@fris.tohoku.ac.jp [Graduate School of Engineering, Tohoku University, Sendai (Japan); Semiconductor R and D Center, Samsung Electronics Co., Ltd., Hwasung (Korea, Republic of); Endoh, T. [Graduate School of Engineering, Tohoku University, Sendai (Japan); Center for Innovative Integrated Electronic Systems, Tohoku University, Sendai (Japan); Kim, Y.; Kim, W. K.; Park, S. O. [Semiconductor R and D Center, Samsung Electronics Co., Ltd., Hwasung (Korea, Republic of)

    2014-05-07T23:59:59.000Z

    To identify the degradation mechanism in magnetic tunnel junctions (MTJs) using hydrogen, the properties of the MTJs were measured by applying an additional hydrogen etch process and a hydrogen plasma process to the patterned MTJs. In these studies, an additional 50?s hydrogen etch process caused the magnetoresistance (MR) to decrease from 103% to 14.7% and the resistance (R) to increase from 6.5?k? to 39?k?. Moreover, an additional 500?s hydrogen plasma process decreased the MR from 103% to 74% and increased R from 6.5?k? to 13.9?k?. These results show that MTJs can be damaged by the hydrogen plasma process as well as by the hydrogen etch process, as the atomic bonds in MgO may break and react with the exposed hydrogen gas. Compounds such as MgO hydrate very easily. We also calculated the damaged layer width (DLW) of the patterned MTJs after the hydrogen etching and plasma processes, to evaluate the downscaling limitations of spin-transfer-torque magnetic random-access memory (STT-MRAM) devices. With these calculations, the maximum DLWs at each side of the MTJ, generated by the etching and plasma processes, were 23.8?nm and 12.8?nm, respectively. This result validates that the hydrogen-based MTJ patterning processes cannot be used exclusively in STT-MRAMs beyond 20?nm.

  8. Direct experimental evidence for the reversal of carrier type upon hydrogen intercalation in epitaxial graphene/SiC(0001)

    SciTech Connect (OSTI)

    Rajput, S., E-mail: srajput@uwm.edu; Li, Y. Y.; Li, L. [Department of Physics, University of Wisconsin, Milwaukee, Wisconsin 53211 (United States)

    2014-01-27T23:59:59.000Z

    Raman spectroscopy and scanning tunneling microscopy/spectroscopy measurements are performed to determine the atomic structure and electronic properties of H-intercalated graphene/SiC(0001) obtained by annealing the as-grown epitaxial graphene in hydrogen atmosphere. While the as-grown graphene is found to be n-type with the Dirac point (E{sub D}) at 450 and 350?meV below Fermi level for the 1st and 2nd layer, the H-intercalated graphene is p-type with E{sub D} at 320 and 200?meV above. In addition, ripples are observed in the now quasi-free standing graphene decoupled from the SiC substrate. This causes fluctuations in the Dirac point that directly follow the undulations of the ripples, resulting in electron and hole puddles in the H-intercalated graphene/SiC(0001)

  9. Regular Type III and Type N Approximate Solutions

    E-Print Network [OSTI]

    Philip Downes; Paul MacAllevey; Bogdan Nita; Ivor Robinson

    2001-05-18T23:59:59.000Z

    New type III and type N approximate solutions which are regular in the linear approximation are shown to exist. For that, we use complex transformations on self-dual Robinson-Trautman metrics rather then the classical approach. The regularity criterion is the boundedness and vanishing at infinity of a scalar obtained by saturating the Bel-Robinson tensor of the first approximation by a time-like vector which is constant with respect to the zeroth approximation.

  10. P-type gallium nitride

    DOE Patents [OSTI]

    Rubin, Michael (Berkeley, CA); Newman, Nathan (Montara, CA); Fu, Tracy (Berkeley, CA); Ross, Jennifer (Pleasanton, CA); Chan, James (Berkeley, CA)

    1997-01-01T23:59:59.000Z

    Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5.times.10.sup.11 /cm.sup.3 and hole mobilities of about 500 cm.sup.2 /V-sec, measured at 250.degree. K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al.

  11. P-type gallium nitride

    DOE Patents [OSTI]

    Rubin, M.; Newman, N.; Fu, T.; Ross, J.; Chan, J.

    1997-08-12T23:59:59.000Z

    Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5{times}10{sup 11} /cm{sup 3} and hole mobilities of about 500 cm{sup 2} /V-sec, measured at 250 K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al. 9 figs.

  12. Resonant tunneling with high peak to valley current ratio in SiO{sub 2}/nc-Si/SiO{sub 2} multi-layers at room temperature

    SciTech Connect (OSTI)

    Chen, D. Y., E-mail: cdy7659@126.com [Department of Physics, Nanjing National Laboratory of Microstructures and Key Laboratory of Advanced Photonic and Electronic, materials, Nanjing University, Nanjing 210093 (China); Nanjing University of posts and Telecommunications, Nanjing 210046 (China); Sun, Y.; He, Y. J. [Nanjing University of posts and Telecommunications, Nanjing 210046 (China); Xu, L.; Xu, J. [Department of Physics, Nanjing National Laboratory of Microstructures and Key Laboratory of Advanced Photonic and Electronic, materials, Nanjing University, Nanjing 210093 (China)

    2014-01-28T23:59:59.000Z

    We have investigated carrier transport in SiO{sub 2}/nc-Si/SiO{sub 2} multi-layers by room temperature current-voltage measurements. Resonant tunneling signatures accompanied by current peaks are observed. Carrier transport in the multi-layers were analyzed by plots of ln(I/V{sup 2}) as a function of 1/V and ln(I) as a function of V{sup 1/2}. Results suggest that besides films quality, nc-Si and barrier sub-layer thicknesses are important parameters that restrict carrier transport. When thicknesses are both small, direct tunneling dominates carrier transport, resonant tunneling occurs only at certain voltages and multi-resonant tunneling related current peaks can be observed but with peak to valley current ratio (PVCR) values smaller than 1.5. When barrier thickness is increased, trap-related and even high field related tunneling is excited, causing that multi-current peaks cannot be observed clearly, only one current peak with higher PVCR value of 7.7 can be observed. While if the thickness of nc-Si is large enough, quantum confinement is not so strong, a broad current peak with PVCR value as high as 60 can be measured, which may be due to small energy difference between the splitting energy levels in the quantum dots of nc-Si. Size distribution in a wide range may cause un-controllability of the peak voltages.

  13. Actinide Sorption in Rainier Mesa Tunnel Waters from the Nevada Test Site

    SciTech Connect (OSTI)

    Zhao, P; Zavarin, M; Leif, R; Powell, B; Singleton, M; Lindvall, R; Kersting, A

    2007-12-17T23:59:59.000Z

    The sorption behavior of americium (Am), plutonium (Pu), neptunium (Np), and uranium (U) in perched Rainier Mesa tunnel water was investigated. Both volcanic zeolitized tuff samples and groundwater samples were collected from Rainier Mesa, Nevada Test Site, NV for a series of batch sorption experiments. Sorption in groundwater with and without the presence of dissolved organic matter (DOM) was investigated. Am(III) and Pu(IV) are more soluble in groundwater that has high concentrations of DOM. The sorption K{sub d} for Am(III) and Pu(IV) on volcanic zeolitized tuff was up to two orders of magnitude lower in samples with high DOM (15 to 19 mg C/L) compared to samples with DOM removed (< 0.4 mg C/L) or samples with naturally low DOM (0.2 mg C/L). In contrast, Np(V) and U(VI) sorption to zeolitized tuff was much less affected by the presence of DOM. The Np(V) and U(VI) sorption Kds were low under all conditions. Importantly, the DOM was not found to significantly sorb to the zeolitized tuff during these experiment. The concentration of DOM in groundwater affects the transport behavior of actinides in the subsurface. The mobility of Am(III) and Pu(IV) is significantly higher in groundwater with elevated levels of DOM resulting in potentially enhanced transport. To accurately model the transport behavior of actinides in groundwater at Rainier Mesa, the low actinide Kd values measured in groundwater with high DOM concentrations must be incorporated in predictive transport models.

  14. A continuum model with a percolation threshold and tunneling-assisted interfacial conductivity for carbon nanotube-based nanocomposites

    SciTech Connect (OSTI)

    Wang, Yang; Weng, George J., E-mail: weng@jove.rutgers.edu [Department of Mechanical and Aerospace Engineering, Rutgers University, New Brunswick, New Jersey 08903 (United States); Meguid, Shaker A. [Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8 (Canada); Hamouda, Abdel Magid [Department of Mechanical and Industrial Engineering, Qatar University, Doha (Qatar)

    2014-05-21T23:59:59.000Z

    A continuum model that possesses several desirable features of the electrical conduction process in carbon-nanotube (CNT) based nanocomposites is developed. Three basic elements are included: (i) percolation threshold, (ii) interface effects, and (iii) tunneling-assisted interfacial conductivity. We approach the first one through the selection of an effective medium theory. We approach the second one by the introduction of a diminishing layer of interface with an interfacial conductivity to build a 'thinly coated' CNT. The third one is introduced through the observation that interface conductivity can be enhanced by electron tunneling which in turn can be facilitated with the formation of CNT networks. We treat this last issue in a continuum fashion by taking the network formation as a statistical process that can be represented by Cauchy's probability density function. The outcome is a simple and yet widely useful model that can simultaneously capture all these fundamental characteristics. It is demonstrated that, without considering the interface effect, the predicted conductivity would be too high, and that, without accounting for the additional contribution from the tunneling-assisted interfacial conductivity, the predicted conductivity beyond the percolation threshold would be too low. It is with the consideration of all three elements that the theory can fully account for the experimentally measured data. We further use the developed model to demonstrate that, despite the anisotropy of the intrinsic CNT conductivity, it is its axial component along the CNT direction that dominates the overall conductivity. This theory is also proved that, even with a totally insulating matrix, it is still capable of delivering non-zero conductivity beyond the percolation threshold.

  15. Type Ia Supernova Explosion Models

    E-Print Network [OSTI]

    W. Hillebrandt; J. C. Niemeyer

    2000-06-21T23:59:59.000Z

    Because calibrated light curves of Type Ia supernovae have become a major tool to determine the local expansion rate of the Universe and also its geometrical structure, considerable attention has been given to models of these events over the past couple of years. There are good reasons to believe that perhaps most Type Ia supernovae are the explosions of white dwarfs that have approached the Chandrasekhar mass, M_ch ~ 1.39 M_sun, and are disrupted by thermonuclear fusion of carbon and oxygen. However, the mechanism whereby such accreting carbon-oxygen white dwarfs explode continues to be uncertain. Recent progress in modeling Type Ia supernovae as well as several of the still open questions are addressed in this review. Although the main emphasis will be on studies of the explosion mechanism itself and on the related physical processes, including the physics of turbulent nuclear combustion in degenerate stars, we also discuss observational constraints.

  16. TESLA-FEL 2007-02 Radiation dosimetry in FLASH Tunnel using

    E-Print Network [OSTI]

    the experimental methods and the results of neutron and gamma dosimetry/spectrometry performed with various types to characterise the radiation field in the FLASH environment. We have evaluated the neutron and gamma energy

  17. A variable-temperature nanostencil compatible with a low-temperature scanning tunneling microscope/atomic force microscope

    SciTech Connect (OSTI)

    Steurer, Wolfram, E-mail: wst@zurich.ibm.com; Gross, Leo; Schlittler, Reto R.; Meyer, Gerhard [IBM Research-Zurich, 8803 Rüschlikon (Switzerland)] [IBM Research-Zurich, 8803 Rüschlikon (Switzerland)

    2014-02-15T23:59:59.000Z

    We describe a nanostencil lithography tool capable of operating at variable temperatures down to 30 K. The setup is compatible with a combined low-temperature scanning tunneling microscope/atomic force microscope located within the same ultra-high-vacuum apparatus. The lateral movement capability of the mask allows the patterning of complex structures. To demonstrate operational functionality of the tool and estimate temperature drift and blurring, we fabricated LiF and NaCl nanostructures on Cu(111) at 77 K.

  18. Generation and diagnostics of atmospheric pressure CO{sub 2} plasma by laser driven plasma wind tunnel

    SciTech Connect (OSTI)

    Matsui, Makoto; Yamagiwa, Yoshiki [Department of Mechanical Engineering, Shizuoka University, 3-5-4 Johoku, Naka, Hamamatsu, 432-8561 Shizuoka (Japan); Tanaka, Kensaku; Arakawa, Yoshihiro [Department of Aeronautics and Astronautics, University of Tokyo, 7-3-1 Hongo, Bunkyo, 113-0033 Tokyo (Japan); Nomura, Satoshi; Komurasaki, Kimiya [Department of Advanced Energy, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8583 Chiba (Japan)

    2012-08-01T23:59:59.000Z

    Atmospheric pressure CO{sub 2} plasma was generated by a laser driven plasma wind tunnel. At an ambient pressure of 0.38 MPa, a stable plasma was maintained by a laser power of 1000 W for more than 20 min. The translational temperature was measured using laser absorption spectroscopy with the atomic oxygen line at 777.19 nm. The measured absorption profiles were analyzed by a Voigt function considering Doppler, Stark, and pressure-broadening effects. Under the assumption of thermochemical equilibrium, all broadening effects were consistent with each other. The measured temperature ranged from 8500 K to 8900 K.

  19. Tunneling between de Sitter and anti-de Sitter black holes in a noncommutative D{sub 3}-brane formalism

    SciTech Connect (OSTI)

    Kar, Supriya [Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, Trieste (Italy); Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India)

    2006-12-15T23:59:59.000Z

    We obtain de Sitter (dS) and anti-de Sitter (AdS) generalized Reissner-Nordstrom-like black hole geometries in a curved D{sub 3}-brane framework, underlying a noncommutative gauge theory on the brane world. The noncommutative scaling limit is explored to investigate a possible tunneling of an AdS vacuum in string theory to dS vacuum in its low energy gravity theory. The Hagedorn transition is invoked into its self-dual gauge theory to decouple the gauge nonlinearity from the dS geometry, which in turn is shown to describe a pure dS vacuum.

  20. Enhancement of band-to-band tunneling in mono-layer transition metal dichalcogenides two-dimensional materials by vacancy defects

    SciTech Connect (OSTI)

    Jiang, Xiang-Wei; Li, Shu-Shen [State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Gong, Jian [School of Physics Science and Technology, Inner Mongolia University, Hohhot 010021 (China); Xu, Nuo [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States); Zhang, Jinfeng; Hao, Yue [Key Laboratory of Wide Band Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi'an 710071 (China); Wang, Lin-Wang, E-mail: lwwang@lbl.gov [Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2014-01-13T23:59:59.000Z

    The band-to-band tunneling of monolayer transition metal dichalcogenides nano-junction is investigated using atomistic ab initio quantum transport simulations. From the simulation, it is found that the transition metal vacancy defect in the two-dimensional MX{sub 2} (M = Mo,W; X = S,Se) band-to-band tunneling diode can dramatically boost the on-state current up to 10 times while maintaining the device sub-threshold swing. The performance enhancement mechanism is discussed in detail by examining partial density of states of the system. It is found that the transition metal vacancy induces band-gap states, which reduce the effective length of the tunneling transition region.

  1. Influence of InGaN sub-quantum-well on performance of InAlN/GaN/InAlN resonant tunneling diodes

    SciTech Connect (OSTI)

    Chen, Haoran; Yang, Lin'an, E-mail: layang@xidian.edu.cn; Hao, Yue [State Key Discipline Laboratory of Wide Bandgap Semiconductor Technology, School of Microelectronics, Xidian University, Xi'an 710071 (China)

    2014-08-21T23:59:59.000Z

    The resonant tunneling mechanism of the GaN based resonant tunneling diode (RTD) with an InGaN sub-quantum-well has been investigated by means of numerical simulation. At resonant-state, Electrons in the InGaN/InAlN/GaN/InAlN RTD tunnel from the emitter region through the aligned discrete energy levels in the InGaN sub-quantum-well and GaN main-quantum-well into the collector region. The implantation of the InGaN sub-quantum-well alters the dominant transport mechanism, increase the transmission coefficient and give rise to the peak current and peak-to-valley current ratio. We also demonstrate that the most pronounced negative-differential-resistance characteristic can be achieved by choosing appropriately the In composition of In{sub x}Ga{sub 1?x}N at around x?=?0.06.

  2. Nonresonant tunneling in InGaP/lnAIP asymmetric double quantum wells 0. Buccafusca, J. L. A. Chilla, C. S. Menoni, J. J. Rocca, M. J. Hafich, L. M. Woods,

    E-Print Network [OSTI]

    Rocca, Jorge J.

    Nonresonant tunneling in InGaP/lnAIP asymmetric double quantum wells 0. Buccafusca, J. L. A. Chilla rates have been measured in InGaP/InAlP asymmetric double quantum-well structures for which optical and computing.g*`O Herein, we report the first tunneling measurements in InGaP/InAlP asymmetric double quan- tum

  3. Country Scotland Type Single malt

    E-Print Network [OSTI]

    Izzard, Rob

    Country Scotland Type Single malt Distillery Aberfeldy Region Highlands Age 12 years ABV 40% Cask, the perfume characteristics become more spicy, with a bitter hint of Seville oranges in a decidedly dry finish. Drying citrus/oak with a gentle spiciness, held in a warm embrace of cigar smoke, and a little vanilla

  4. Country Scotland Type Single malt

    E-Print Network [OSTI]

    Izzard, Rob

    Country Scotland Type Single malt Distillery Jura Region Island Name Prophecy ABV 46 Cask French airport Notes Limited annual release: 10,000 bottles only. Nose Some peat, aniseed, oily, dry, pungent, dried hay, and anise round things out. Palate Smoky and dry, a muscular, powerful Jura with notes

  5. Automatic Utterance Type Detection Using Suprasegmental Features 

    E-Print Network [OSTI]

    Wright, Helen

    that different types of utterances have different suprasegmental characteristics. The categorisation of these utterance types is based on the theory of conversation games and consists of 12 move types (e.g. reply to a question, wh-question, acknowledgement...

  6. LER-LHC injector workshop summary and super-ferric fast cycling injector in the SPS tunnel

    SciTech Connect (OSTI)

    Ambrosio, Giorgio; Hays, Steven; Huang, Yuenian; Johnstone, John; Kashikhin, Vadim; MacLachlan, James; Mokhov, Nikolai; Piekarz, Henryk; Sen, Tanaji; Shiltsev, Vladimir; /Fermilab; de Rijk, Gijsbert; /CERN

    2007-03-01T23:59:59.000Z

    A Workshop on Low Energy Ring (LER) in the LHC tunnel as main injector was convened at CERN on October 11-12, 2006. We present the outline of the LER based on the presentations, and respond to the raised questions and discussions including the post-workshop studies. We also outline the possibility of using the LER accelerator technologies for the fast cycling injector accelerator in the SPS tunnel (SF-SPS). A primary goal for the LER (Low Energy Ring) injector accelerator is to inject 1.5 TeV proton beams into the LHC, instead of the current injection scheme with 0.45 TeV beams from the SPS. At this new energy, the field harmonics [1] of the LHC magnets are sufficiently satisfactory to prevent the luminosity losses expected to appear when applying the transfer of the 0.45 TeV SPS beams. In addition, a feasibility study of batch slip stacking in the LER has been undertaken with a goal of increasing in this way the LHC luminosity by up to a factor of 4. A combined luminosity increase may, therefore, be in the range of an order of magnitude. In the long term, the LER injector accelerator would greatly facilitate the implementation of a machine, which doubles the LHC energy (DLHC).

  7. High-field electroluminescence in semiconductor tunnel junctions with a Mn-doped GaAs layer

    SciTech Connect (OSTI)

    Hai, Pham Nam [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-0033 (Japan); Yatsui, Takashi; Ohtsu, Motoichi; Tanaka, Masaaki [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nanophotonics Research Center, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2014-09-21T23:59:59.000Z

    We investigated high-field electroluminescence (EL) in semiconductor tunnel junctions with a Mn-doped GaAs layer (here, referred to as GaAs:Mn). Besides the band-gap emission of GaAs, the EL spectra show visible light emissions with two peaks at 1.94?eV and 2.19?eV, which are caused by d-d transitions of the Mn atoms excited by hot electrons. The threshold voltages for band-gap and visible light EL in the tunnel junctions with a GaAs:Mn electrode are 1.3?V higher than those of GaAs:Mn excited by hot holes in reserve biased p{sup +}-n junctions, which is consistent with the hot carrier transport in the band profiles of these structures. Our EL results at room temperature show that the electron temperature in GaAs:Mn can be as high as ?700?K for a low input electrical power density of 0.4?W/cm{sup 2}, while the lattice temperature of the GaAs:Mn layer can be kept at 340?K.

  8. Tridiagonal pairs of Krawtchouk type

    E-Print Network [OSTI]

    Ito, Tatsuro

    2007-01-01T23:59:59.000Z

    Let $K$ denote an algebraically closed field with characteristic 0 and let $V$ denote a vector space over $K$ with finite positive dimension. Let $A,A^*$ denote a tridiagonal pair on $V$ with diameter $d$. We say that $A,A^*$ has Krawtchouk type whenever the sequence $\\lbrace d-2i\\rbrace_{i=0}^d$ is a standard ordering of the eigenvalues of $A$ and a standard ordering of the eigenvalues of $A^*$. Assume $A,A^*$ has Krawtchouk type. We show that there exists a nondegenerate symmetric bilinear form $$ on $V$ such that $= $ and $= $ for $u,v\\in V$. We show that the following tridiagonal pairs are isomorphic: (i) $A,A^*$; (ii) $-A,-A^*$; (iii) $A^*,A$; (iv) $-A^*,-A$. We give a number of related results and conjectures.

  9. Abstract DNA-type systems

    E-Print Network [OSTI]

    Diederik Aerts; Marek Czachor

    2005-12-22T23:59:59.000Z

    An abstract DNA-type system is defined by a set of nonlinear kinetic equations with polynomial nonlinearities that admit soliton solutions associated with helical geometry. The set of equations allows for two different Lax representations: A von Neumann form and a Darboux-covariant Lax pair. We explain why non-Kolmogorovian probability models occurring in soliton kinetics are naturally associated with chemical reactions. The most general known characterization of soliton kinetic equations is given and a class of explicit soliton solutions is discussed. Switching between open and closed states is a generic behaviour of the helices. The effect does not crucially depend on the order of nonlinearity (i.e. types of reactions), a fact that may explain why simplified models possess properties occuring in realistic systems. We explain also why fluctuations based on Darboux transformations will not destroy the dynamics but only switch between a finite number of helical structures.

  10. Niger Delta play types, Nigeria

    SciTech Connect (OSTI)

    Akinpelu, A.O. [Chevron Nigeria Limited, Lagos (Nigeria)

    1995-08-01T23:59:59.000Z

    Exploration databases can be more valuable when sorted by play type. Play specific databases provide a system to organize E & P data used in evaluating the range of values of parameters for reserve estimation and risk assessment. It is important both in focusing the knowledge base and in orienting research effort. A play in this context is any unique combination of trap, reservoir and source properties with the right dynamics of migration and preservation that results in hydrocarbon accumulation. This definitions helps us to discriminate the subtle differences found with these accumulation settings. About 20 play types were identified around the Niger Delta oil province in Nigeria. These are grouped into three parts: (1) The proven plays-constituting the bulk of exploration prospects in Nigeria today. (2) The unproven or semi-proven plays usually with some successes recorded in a few tries but where knowledge is still inadequate. (3) The unproven or analogous play concept. These are untested but geologically sound ideas which may or may not have been tried elsewhere. With classification and sub grouping of these play types into specific databases, intrinsic attributes and uniqueness of each of them with respect to the four major risk elements and the eight parameters for reserve estimation can be better understood.

  11. Staircase and saw-tooth field emission steps from nanopatterned n-type GaSb surfaces

    SciTech Connect (OSTI)

    Kildemo, M.; Levinsen, Y. Inntjore; Le Roy, S.; Soenderga ring rd, E. [Department of Physics, Norwegian University of Science and Technology (NTNU), NO-7491 Trondlieim (Norway); Department of Physics, Norwegian University of Science and Technology (NTNU), NO-7491 Trondlieim, Norway and AB CERN, CH- 1211 Geneva 23 (Switzerland); Laboratoire Surface du Verre et Interfaces, UMR 125 Unite Mixte de Recherche CNRS/Saint-Gobain Laboratoire, 39 Quai Lucien Lefranc, F-93303 Aubervilliers Cedex (France)

    2009-09-15T23:59:59.000Z

    High resolution field emission experiments from nanopatterned GaSb surfaces consisting of densely packed nanocones prepared by low ion-beam-energy sputtering are presented. Both uncovered and metal-covered nanopatterned surfaces were studied. Surprisingly, the field emission takes place by regular steps in the field emitted current. Depending on the field, the steps are either regular, flat, plateaus, or saw-tooth shaped. To the author's knowledge, this is the first time that such results have been reported. Each discrete jump in the field emission may be understood in terms of resonant tunneling through an extended surface space charge region in an n-type, high aspect ratio, single GaSb nanocone. The staircase shape may be understood from the spatial distribution of the aspect ratio of the cones.

  12. Wind Tunnel Aerodynamic Tests of Six Airfoils for Use on Small Wind Turbines; Period of Performance: October 31, 2002--January 31, 2003

    SciTech Connect (OSTI)

    Selig, M. S.; McGranahan, B. D.

    2004-10-01T23:59:59.000Z

    Wind Tunnel Aerodynamic Tests of Six Airfoils for Use on Small Wind Turbinesrepresents the fourth installment in a series of volumes documenting the ongoing work of th University of Illinois at Urbana-Champaign Low-Speed Airfoil Tests Program. This particular volume deals with airfoils that are candidates for use on small wind turbines, which operate at low Reynolds numbers.

  13. Surface Plasmon and Geometry Enhanced Asymmetric Rectifying Tunneling Diodes Kwangsik Choi, Geunmin Ryu, Filiz Yesilkoy, Athanasios Chryssis, Mario Dagenais, Neil Goldsman and Martin

    E-Print Network [OSTI]

    Dagenais, Mario

    Surface Plasmon and Geometry Enhanced Asymmetric Rectifying Tunneling Diodes Kwangsik Choi, Geunmin Another scheme for obtaining high efficiency rectification employs surface plasmon resonances (SPRs) in nanoscale optical antennas. This is the emphasis of the work reported here. Surface plasmon (SP) waves can

  14. Heating-compensated constant-temperature tunneling measurements on stacks of Bi2Sr2CaCu2O8+x intrinsic junctions

    E-Print Network [OSTI]

    Lee, Hu-Jong

    measurements on a stack of intrinsic junctions IJs in a high-bias range are often susceptible to self-heating one to get rid of spurious tunneling effects arising from the self-heating. © 2005 American Institute. The poor thermal conductivity of the Bi-2212 IJs, how- ever, is known to cause serious local self-heating

  15. Atomic-Scale Investigation of Epitaxial Graphene Grown on 6H-SiC(0001) Using Scanning Tunneling Microscopy and Spectroscopy

    E-Print Network [OSTI]

    Kim, Sehun

    Atomic-Scale Investigation of Epitaxial Graphene Grown on 6H-SiC(0001) Using Scanning Tunneling ReceiVed: June 26, 2010 Graphene was epitaxially grown on a 6H-SiC(0001) substrate by thermal the evolution of the graphene growth as a function of the temperature. We found that the evaporation of Si

  16. A Model for Tunneling-Limited Breakdown in High-Power HEMTs Mark H. Somerville and Jes6s A. del Alamo

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    A Model for Tunneling-Limited Breakdown in High-Power HEMTs Mark H. Somerville and Jes6s A. del indicates that the cru- cial variables in determining the off-state breakdown volt- age of power HEMTs. Other design parameters have only secondary impact on the breakdown voltage for realistic device designs

  17. Effect of a magnetic field on the instability of the nonequilibrium state of superconducting Nb films in the case of tunnel injection of quasi-particles

    SciTech Connect (OSTI)

    Pan, V.; Rudenko, E.; Nevirkovets, I.; Shaternik, V.

    1981-11-01T23:59:59.000Z

    The effect of an external magnetic field on the instability of the nonequilibrium state of superconducting films of niobium when there is tunnel injection of quasi-particles has been studied and it was shown that increasing the magnetic field reduces the value of the instability current. (AIP)

  18. The thermoelectric properties of molecular junctions can now be investigated with scanning tunnelling microscopy. Such experiments provide insights into charge transport in single

    E-Print Network [OSTI]

    Heller, Eric

    The thermoelectric properties of molecular junctions can now be investigated with scanning . They used a scanning tunnelling microscope (STM) to investigate thermoelectricity -- the voltage generated that thermoelectric measurements by STM provide a solution to this problem MOLECULAR ELECTRONICS Charges feel the heat

  19. 1D to 1D Tunneling in a Dual Electron Waveguide Device C. C. Euaster, J. A. del Alamo,M. R. Mellocht, M. J. Rooks*

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    1D to 1D Tunneling in a Dual Electron Waveguide Device C. C. Euaster, J. A. del Alamo,M. R on a dual electron waveguide device. In this device, two closely spaced 1D channels are electrostati- cally have fabricated a variety of dual electron waveguide devices with different lengths L and widths W

  20. Comparison of decoherence and Zeno dynamics from the context of weak measurement for a two level atom tunneling through squeezed vacuum

    E-Print Network [OSTI]

    Samyadeb Bhattacharya

    2014-10-22T23:59:59.000Z

    Decay parameter of coherence and population inversion are calculated from the master equation of a two level atom tunneling through a squeezed vacuum. Using those parameters, the timescales for decoherence and zeno effect are calculated in the weak measurement scheme. By comparing those timescales, a certain condition has been found for sustainable coherent dynamics.

  1. Terahertz vibration-rotation-tunneling spectroscopy of the water tetramer-d8: Combined analysis of vibrational bands at 4.1 and 2.0 THz

    E-Print Network [OSTI]

    Cohen, Ronald C.

    Terahertz vibration-rotation-tunneling spectroscopy of the water tetramer-d8: Combined analysis in the global fit of the water trimer. The detailed understanding of the water tetramer evolving from this work calculated concentrations of water trimers, tetramers, and pentamers of 1012 , 1011 , and 1010 cm-3

  2. Terahertz Laser Vibration-Rotation Tunneling Spectroscopy of the Water Tetramer Jeff D. Cruzan, Mark R. Viant, Mac G. Brown, and Richard J. Saykally*

    E-Print Network [OSTI]

    Cohen, Ronald C.

    Terahertz Laser Vibration-Rotation Tunneling Spectroscopy of the Water Tetramer Jeff D. Cruzan, which increase nonlinearly with increasing J, were found in both D2O and H2O tetramer spectra. Evidence of 1% of the total stabilization energy of the tetramer and pentamer.12-21 Xantheas' recent MP2

  3. hal00270574, Testing Data Types Implementations from

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    is data type abstraction, testing a concrete implementation raises the issue of the gap betweenhal­00270574, version 1 ­ 6 Apr 2008 Testing Data Types Implementations from Algebraic Speci#12.legall@ibisc.univ-evry.fr Abstract. Algebraic speci#12;cations of data types provide a natural basis for testing data types

  4. XML Document XML Document Types and Validation

    E-Print Network [OSTI]

    Weber, Gregory D.

    XML Document Types and Validation IIM-I340 Objectives XML Document Types and Validation IIM-I340 April, 2010 #12;XML Document Types and Validation IIM-I340 Objectives Learning Objectives Understand: The need for validation Two ways to specify validity: Document Type Definitions (DTDs) XML Schemas #12;XML

  5. Electronic Phase Separation in Pr sub 1 sub x (Ca, Sr) sub x MnO sub 3 subdelta and Tunneling Magnetoresistance in Sr sub 2 FeMoO sub 6

    E-Print Network [OSTI]

    Niebieskikwiat, D G

    2003-01-01T23:59:59.000Z

    In this work, we approach two aspects of the physics of magnetic perovskites presenting colossal magnetoresistance (CMR). Firstly, we go deeply into the phase separation (PS) between the ferromagnetic (FM) metallic state and the antiferro-magnetic (AFM) charge ordered (CO) insulating state, in manganites of the type Pr sub 1 sub x (Ca,Sr) sub x MnO sub 3 subdelta. Secondly, and more briefly, we analyze the problem of the influence of the grain boundary insulating barriers on the tunneling magnetoresistance in the Sr sub 2 FeMoO sub 6 double perovskite.The use of different measurement techniques allowed us to make a complete characterization of the PS state in the compounds Pr sub 0.65Ca sub 0 sub . sub 3 sub 5 sub - sub y Sr sub y MnO sub 3 for 0 ) keeping constant the carrier concentration (x = 0.35). This material presents an evolution from a CO insulating phase for small (y =0), towards the FM metallic phase for large (y = 0.20). In t

  6. Wheel-type magnetic refrigerator

    DOE Patents [OSTI]

    Barclay, John A. (Los Alamos, NM)

    1983-01-01T23:59:59.000Z

    The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load.

  7. Wheel-type magnetic refrigerator

    DOE Patents [OSTI]

    Barclay, J.A.

    1982-01-20T23:59:59.000Z

    The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load.

  8. Wheel-type magnetic refrigerator

    DOE Patents [OSTI]

    Barclay, J.A.

    1983-10-11T23:59:59.000Z

    The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load. 7 figs.

  9. Error propagation equations and tables for estimating the uncertainty in high-speed wind tunnel test results

    SciTech Connect (OSTI)

    Clark, E.L.

    1993-08-01T23:59:59.000Z

    Error propagation equations, based on the Taylor series model, are derived for the nondimensional ratios and coefficients most often encountered in high-speed wind tunnel testing. These include pressure ratio and coefficient, static force and moment coefficients, dynamic stability coefficients, calibration Mach number and Reynolds number. The error equations contain partial derivatives, denoted as sensitivity coefficients, which define the influence of free-stream Mach number, M{infinity}, on various aerodynamic ratios. To facilitate use of the error equations, sensitivity coefficients are derived and evaluated for nine fundamental aerodynamic ratios, most of which relate free-stream test conditions (pressure, temperature, density or velocity) to a reference condition. Tables of the ratios, R, absolute sensitivity coefficients, {partial_derivative}R/{partial_derivative}M{infinity}, and relative sensitivity coefficients, (M{infinity}/R) ({partial_derivative}R/{partial_derivative}M{infinity}), are provided as functions of M{infinity}.

  10. Boron diffusion in magnetic tunnel junctions with MgO (001) barriers and CoFeB electrodes

    SciTech Connect (OSTI)

    Kurt, H.; Rode, K.; Oguz, K.; Coey, J. M. D. [School of Physics and CRANN, Trinity College, Dublin 2 (Ireland); Boese, M.; Faulkner, C. C. [Advanced Microscopy Laboratory, CRANN, Trinity College, Dublin 2 (Ireland)

    2010-06-28T23:59:59.000Z

    Boron diffusion out of the CoFeB layers in model systems with thick CoFeB and MgO layers grown by radiofrequency sputtering or electron-beam evaporation and in MgO-based magnetic tunnel junctions (MTJs) is probed after annealing by x-ray photoemission spectroscopy (XPS) and electron energy loss spectroscopy. Successive interfaces are exposed by ion milling the stacks, layer by layer, in the XPS system. Despite the presence of thick CoFeB and a high annealing temperature of 400 deg. C, we found no boron in the MgO or at the MgO/CoFe interfaces. Similar results are also obtained in the MTJs.

  11. DNA and RNA sequencing by nanoscale reading through programmable electrophoresis and nanoelectrode-gated tunneling and dielectric detection

    DOE Patents [OSTI]

    Lee, James W.; Thundat, Thomas G.

    2005-06-14T23:59:59.000Z

    An apparatus and method for performing nucleic acid (DNA and/or RNA) sequencing on a single molecule. The genetic sequence information is obtained by probing through a DNA or RNA molecule base by base at nanometer scale as though looking through a strip of movie film. This DNA sequencing nanotechnology has the theoretical capability of performing DNA sequencing at a maximal rate of about 1,000,000 bases per second. This enhanced performance is made possible by a series of innovations including: novel applications of a fine-tuned nanometer gap for passage of a single DNA or RNA molecule; thin layer microfluidics for sample loading and delivery; and programmable electric fields for precise control of DNA or RNA movement. Detection methods include nanoelectrode-gated tunneling current measurements, dielectric molecular characterization, and atomic force microscopy/electrostatic force microscopy (AFM/EFM) probing for nanoscale reading of the nucleic acid sequences.

  12. Effects of Be acceptors on the spin polarization of carriers in p-i-n resonant tunneling diodes

    SciTech Connect (OSTI)

    Awan, I. T.; Galvão Gobato, Y. [Departamento de Física, Universidade Federal de São Carlos (UFSCAR) 13560-905, São Carlos, SP (Brazil); Galeti, H. V. A. [Departamento de Engenharia Elétrica, Universidade Federal de São Carlos 13560-905, São Carlos, SP (Brazil); Brasil, M. J. S. P. [Institute of Physics Gleb Wataghin, UNICAMP, Campinas (Brazil); Taylor, D.; Henini, M. [School of Physics and Astronomy, Nottingham Nanotechnology and Nanoscience Centre, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

    2014-08-07T23:59:59.000Z

    In this paper, we have investigated the effect of Be acceptors on the electroluminescence and the spin polarization in GaAs/AlAs p-i-n resonant tunneling diodes. The quantum well emission comprise two main lines separated by ?20?meV attributed to excitonic and Be-related transitions, which intensities show remarkably abrupt variations at critical voltages, particularly at the electron resonant peak where it shows a high-frequency bistability. The circular-polarization degree of the quantum-well electroluminescence also shows strong and abrupt variations at the critical bias voltages and it attains relatively large values (of ??75% at 15?T). These effects may be explored to design novel devices for spintronic applications such as a high-frequency spin-oscillators.

  13. Optimization in the Parikh-Wilczek tunneling model of Hawking radiation for Kerr-Newman Black Holes

    E-Print Network [OSTI]

    Auttakit Chatrabhuti; Khem Upathambhakul

    2014-03-17T23:59:59.000Z

    In this short report, we investigate the mutual information hidden in the Parikh-Wilczek tunneling model of Hawking radiation for Kerr-Newman black holes. By assuming the radiation as an optimization process, we discuss its effect on time evolution of rotating (charged and uncharged) black holes. For uncharged rotating black holes evaporating under the maximum mutual information optimization, their scale invariant rotation parameter $a_*=a/M$ is almost constant at the early stage but rapidly increase at the very last stage of the evaluation process. The value of rotation parameter at the final state of evaporation depends on the initial condition of the black hole. We also found that the presence of electric charge can cause the black holes lose their angular momentum more rapidly than they lose mass. The charged-rotating black holes asymptotically approach a state which is described by $a_*= 0$ and $Q/M = 1$.

  14. Mixed quantum classical calculation of proton transfer reaction rates: From deep tunneling to over the barrier regimes

    SciTech Connect (OSTI)

    Xie, Weiwei; Xu, Yang; Zhu, Lili; Shi, Qiang, E-mail: qshi@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190 (China)] [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190 (China)

    2014-05-07T23:59:59.000Z

    We present mixed quantum classical calculations of the proton transfer (PT) reaction rates represented by a double well system coupled to a dissipative bath. The rate constants are calculated within the so called nontraditional view of the PT reaction, where the proton motion is quantized and the solvent polarization is used as the reaction coordinate. Quantization of the proton degree of freedom results in a problem of non-adiabatic dynamics. By employing the reactive flux formulation of the rate constant, the initial sampling starts from the transition state defined using the collective reaction coordinate. Dynamics of the collective reaction coordinate is treated classically as over damped diffusive motion, for which the equation of motion can be derived using the path integral, or the mixed quantum classical Liouville equation methods. The calculated mixed quantum classical rate constants agree well with the results from the numerically exact hierarchical equation of motion approach for a broad range of model parameters. Moreover, we are able to obtain contributions from each vibrational state to the total reaction rate, which helps to understand the reaction mechanism from the deep tunneling to over the barrier regimes. The numerical results are also compared with those from existing approximate theories based on calculations of the non-adiabatic transmission coefficients. It is found that the two-surface Landau-Zener formula works well in calculating the transmission coefficients in the deep tunneling regime, where the crossing point between the two lowest vibrational states dominates the total reaction rate. When multiple vibrational levels are involved, including additional crossing points on the free energy surfaces is important to obtain the correct reaction rate using the Landau-Zener formula.

  15. Double injection, resonant-tunneling recombination, and current-voltage characteristics in double-graphene-layer structures

    SciTech Connect (OSTI)

    Ryzhii, M. [Department of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Ryzhii, V. [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Institute of Ultra High Frequency Semiconductor Electronics, Russian Academy of Sciences, Moscow 111005 (Russian Federation); Otsuji, T. [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Maltsev, P. P. [Institute of Ultra High Frequency Semiconductor Electronics, Russian Academy of Sciences, Moscow 111005 (Russian Federation); Leiman, V. G. [Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700 (Russian Federation); Ryabova, N. [Department of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Center for Photonics and Infrared Engineering, Bauman Moscow State Technical University, Moscow 105005 (Russian Federation); Mitin, V. [Department of Electrical Engineering, University at Buffalo, Buffalo, New York 1460-1920 (United States)

    2014-01-14T23:59:59.000Z

    We evaluate the effect of the recombination associated with interlayer transitions in ungated and gated double-graphene-layer (GL) structures on the injection of electrons and holes. Using the proposed model, we derive analytical expressions for the spatial distributions of the electron and hole Fermi energies and the energy gap between the Dirac points in GLs as well as their dependences on the bias and gate voltages. The current-voltage characteristics are calculated as well. The model is based on hydrodynamic equations for the electron and hole transports in GLs under the self-consistent electric field. It is shown that in undoped double-GL structures with weak scattering of electrons and holes on disorder, the Fermi energies and the energy gap are virtually constant across the main portions of GLs, although their values strongly depend on the voltages and recombination parameters. In contrast, the electron and hole scattering on disorder lead to substantial nonuniformities. The resonant inter-GL tunneling enables N-shaped current-voltage characteristics provided that GLs are sufficiently short. The width of the current maxima is much larger than the broadening of the tunneling resonance. In the double-GL structures with relatively long GLs, the N-shaped characteristics transform into the Z-shaped characteristics. The obtained results are in line with the experimental observations [Britnell et al., Nat. Commun. 4, 1794–1799 (2013)] and might be useful for design and optimization of different devices based on double-GL structures, including field-effect transistors and terahertz lasers.

  16. Hydrogen in Type Ic Supernovae?

    E-Print Network [OSTI]

    David Branch; David J. Jeffery; Timothy R. Young; E. Baron

    2006-05-09T23:59:59.000Z

    By definition, a Type Ic supernova (SN Ic) does not have conspicuous lines of hydrogen or helium in its optical spectrum. SNe Ic usually are modelled in terms of the gravitational collapse of bare carbon-oxygen cores. We consider the possibility that the spectra of ordinary (SN 1994I-like) SNe Ic have been misinterpreted, and that SNe Ic eject hydrogen. An absorption feature usually attributed to a blend of Si II 6355 and C II 6580 may be produced by H-alpha. If SN 1994I-like SNe Ic eject hydrogen, the possibility that hypernova (SN 1998bw-like) SNe Ic, some of which are associated with gamma-ray bursts, also eject hydrogen should be considered. The implications of hydrogen for SN Ic progenitors and explosion models are briefly discussed.

  17. Proof and Definition in Logic and Type Theory Proof and Definition in Logic and Type Theory

    E-Print Network [OSTI]

    Adams, Robin

    Proof and Definition in Logic and Type Theory Proof and Definition in Logic and Type Theory Robin questions. #12;Proof and Definition in Logic and Type Theory Definition and Proof Definition and proof -- but they are not in predicate logic or type theory. #12;Proof and Definition in Logic and Type Theory Methods of Definition

  18. Archive Reference Buildings by Building Type: Supermarket

    Broader source: Energy.gov [DOE]

    Here you will find past versions of the reference buildings for new construction commercial buildings, organized by building type and location. A summary of building types and climate zones is...

  19. Archive Reference Buildings by Building Type: Warehouse

    Broader source: Energy.gov [DOE]

    Here you will find past versions of the reference buildings for new construction commercial buildings, organized by building type and location. A summary of building types and climate zones is...

  20. New approaches for modeling type Ia supernovae

    E-Print Network [OSTI]

    Zingale, Michael; Almgren, Ann S.; Bell, John B.; Day, Marcus S.; Rendleman, Charles A.; Woosley, Stan

    2007-01-01T23:59:59.000Z

    ich and J. Stein. On the thermonuclear runaway in Type IaSmall-Scale Stability of Thermonuclear Flames o in Type IaS. E. Woosley. The thermonuclear explosion of chandrasekhar

  1. Double field theory of type II strings

    E-Print Network [OSTI]

    Hohm, Olaf

    We use double field theory to give a unified description of the low energy limits of type IIA and type IIB superstrings. The Ramond-Ramond potentials fit into spinor representations of the duality group O(D, D) and ...

  2. Ideal bandpasses for type Ia supernova cosmology

    E-Print Network [OSTI]

    Davis, Tamara M.; Schmidt, Brian P.; Kim, Alex G.

    2005-01-01T23:59:59.000Z

    diversity of type Ia Supernovae, in preparation. Kim, A.error in measurements of supernovae depends on a periodicABSTRACT To use type Ia supernovae as standard candles for

  3. Overload permit rules applicable to H-type and HS-type bridges

    E-Print Network [OSTI]

    Litchfield, Stephen Charles

    1994-01-01T23:59:59.000Z

    This document defines standards for issuing permits for overweight vehicles crossing standard H-type and HS-type Texas highway bridges. A general formula and a bridge specific formula have been developed for simple spans of both bridge types...

  4. Rates and progenitors of type Ia supernovae

    E-Print Network [OSTI]

    Wood-Vasey, William Michael

    2004-01-01T23:59:59.000Z

    Supernovae . . . . . . . . . . . . . . . . . . . .Supernovae Found 5.1 Introduction . . . . . . . . . . . .1.2 Non-Type Ia Supernovae . . . . . . . . . . . . . . . 1.3

  5. Fuzzy Typing for Document Management Alison HUETTNER

    E-Print Network [OSTI]

    Wu, Dekai

    Fuzzy Typing for Document Management Alison HUETTNER Clairvoyance Corporation 5301 Fifth Avenue method of document analysis and management, based on a combination of techniques from NLP and fuzzy logic typing for document management. The fuzzy typing approach is general in scope and can be applied to many

  6. Department of Defense/Department of Energy joint demilitarization technology demonstration program executive summary of Phase II demonstrations: The low-pressure rocket motor burns in X-Tunnel

    SciTech Connect (OSTI)

    B. W. Bellow; A. E. Moeller; D. Steele; S. M. Williams; R. L. Heinle; C. O. Pruneda; C. A. Velsko; B. E. Watkins; C. J. Hewitt; H. Fry; J. A. Sanchez; J. R. Stephens; J. R. Carson; W. C. Gray; W. C. Thomas; T. J. Tope; S. W. Allendorf; L. R. Carrillo; H. H. Hirano; H. A. Johnsen; J. Lipkin; D. K. Ottesen; R. L. Peabody; C. R. Shaddix; J. C. Swearengen; R. F. Boehm; A. Smiecinski; K. J. Stetzenback

    1999-12-01T23:59:59.000Z

    Three low-pressure rocket motor burn tests were executed in May--June 1997 time frame at the X-tunnel complex located on the Department of Energy's Nevada Test Site.

  7. Nucleosynthesis in Type Ia Supernovae

    E-Print Network [OSTI]

    K. Nomoto; K. Iwamoto; N. Nakasato; F. -K. Thielemann; F. Brachwitz; T. Tsujimoto; Y. Kubo; N. Kishimoto

    1997-06-03T23:59:59.000Z

    Among the major uncertainties involved in the Chandrasekhar mass models for Type Ia supernovae are the companion star of the accreting white dwarf (or the accretion rate that determines the carbon ignition density) and the flame speed after ignition. We present nucleosynthesis results from relatively slow deflagration (1.5 - 3 % of the sound speed) to constrain the rate of accretion from the companion star. Because of electron capture, a significant amount of neutron-rich species such as ^{54}Cr, ^{50}Ti, ^{58}Fe, ^{62}Ni, etc. are synthesized in the central region. To avoid the too large ratios of ^{54}Cr/^{56}Fe and ^{50}Ti/^{56}Fe, the central density of the white dwarf at thermonuclear runaway must be as low as \\ltsim 2 \\e9 \\gmc. Such a low central density can be realized by the accretion as fast as $\\dot M \\gtsim 1 \\times 10^{-7} M_\\odot yr^{-1}$. These rapidly accreting white dwarfs might correspond to the super-soft X-ray sources.

  8. Type Ia Supernova Carbon Footprints

    E-Print Network [OSTI]

    Thomas, R C; Aragon, C; Antilogus, P; Bailey, S; Baltay, C; Bongard, S; Buton, C; Canto, A; Childress, M; Chotard, N; Copin, Y; Fakhouri, H K; Gangler, E; Hsiao, E Y; Kerschhaggl, M; Kowalski, M; Loken, S; Nugent, P; Paech, K; Pain, R; Pecontal, E; Pereira, R; Perlmutter, S; Rabinowitz, D; Rigault, M; Rubin, D; Runge, K; Scalzo, R; Smadja, G; Tao, C; Weaver, B A; Wu, C; Brown, P J; Milne, P A

    2011-01-01T23:59:59.000Z

    We present convincing evidence of unburned carbon at photospheric velocities in new observations of 5 Type Ia supernovae (SNe Ia) obtained by the Nearby Supernova Factory. These SNe are identified by examining 346 spectra from 124 SNe obtained before +2.5 d relative to maximum. Detections are based on the presence of relatively strong C II 6580 absorption "notches" in multiple spectra of each SN, aided by automated fitting with the SYNAPPS code. Four of the 5 SNe in question are otherwise spectroscopically unremarkable, with ions and ejection velocities typical of SNe Ia, but spectra of the fifth exhibits high-velocity (v > 20,000 km/s) Si II and Ca II features. On the other hand, the light curve properties are preferentially grouped, strongly suggesting a connection between carbon-positivity and broad band light curve/color behavior: Three of the 5 have relatively narrow light curves but also blue colors, and a fourth may be a dust-reddened member of this family. Accounting for signal-to-noise and phase, we ...

  9. Superconductivity: coherent "tunnelling" by a dielectric array of charge-carriers

    E-Print Network [OSTI]

    Johan F. Prins

    2006-07-25T23:59:59.000Z

    Superconduction manifests when a steady-state current flows through a material without an electric field being present. It is argued here that the absence of scattering of the charge-carriers, although absolutely necessary, is not sufficient to explain why an electric field is zero when a current flows between two contacts to a superconducting material. It is concluded that an electric field, and thus a resistance, must manifest unless (i) the charge-carriers form part of an array of dielectric charge centres, and (ii) the charge-carriers can increase their velocities without increasing their kinetic energies. A model is propoased which allows these requirements to manifest. The model is fitted to selected experimental results which have been published for low temperature metals, YBCO, and highly-doped p-type diamond. In each case a satisfactory description of the experimental results is demonstrated.

  10. Proposal to negotiate an amendment to an existing contract for the supply and installation of pipelines for the LHC accelerator tunnel

    E-Print Network [OSTI]

    2003-01-01T23:59:59.000Z

    This document concerns the proposal to negotiate an amendment to an existing contract for the supply and installation of pipelines for the LHC accelerator tunnel. For the reasons explained in this document, the Finance Committee is invited to approve an amendment to the existing contract for the supply and installation of pipelines for the LHC accelerator tunnel with the firm RENCO (IT) for an amount exceeding the previously approved amount of 21 995 304 Swiss francs by up to 5 000 000 Swiss francs, not subject to revision, bringing the total contract amount to a maximum amount of 26 995 304 Swiss francs, not subject to revision. The firm has declared the following origin of the equipment covered by this adjudication proposal: IT - 100%.

  11. Room temperature magnetoresistance in CoFeB/SrTiO{sub 3}/CoFeB magnetic tunnel junctions deposited by ion beam sputtering

    SciTech Connect (OSTI)

    Hassen, E. M. J. [CEA, LETI, MINATEC Campus, Grenoble (France); SPINTEC (UMR 8191 CEA-CNRS-UJF), CEA-INAC, 38054 Grenoble Cedex (France); Viala, B.; Cyrille, M. C.; Cartier, M.; Redon, O. [CEA, LETI, MINATEC Campus, Grenoble (France); Lima, P. [SPTS, Process Technology Systems, Ringland Way, Newport (United Kingdom); Belhadji, B.; Yang, H. X.; Chshiev, M. [SPINTEC (UMR 8191 CEA-CNRS-UJF), CEA-INAC, 38054 Grenoble Cedex (France); Velev, J. [Department of Physics, University of Puerto Rico, San Juan 00931 (Puerto Rico)

    2012-04-01T23:59:59.000Z

    Room temperature transport properties are reported in polycrystalline SrTiO{sub 3}-based magnetic tunnel junctions deposited by ion beam sputtering. The junctions comprise CoFeB electrodes and the SrTiO{sub 3} barrier with thickness varied between 0.9 and 1.9 nm. Resistance area product values between 3 {Omega}.{mu}m{sup 2} and 22 k{Omega}.{mu}m{sup 2} have been measured with a tunnel magnetoresistance ratio ranging from 3.1 to 13% at room temperature. At low barrier thickness (1.2 nm), ferromagnetic coupling between electrodes is observed, indicating the presence of defects in the structure. A post-oxidation step was found to improve transport properties at lower barrier thickness.

  12. GaAs, AlGaAs and InGaP Tunnel Junctions for Multi-Junction Solar Cells Under Concentration: Resistance Study

    SciTech Connect (OSTI)

    Wheeldon, Jeffrey F.; Valdivia, Christopher E.; Walker, Alex; Kolhatkar, Gitanja; Hall, Trevor J.; Hinzer, Karin [Centre for Research in Photonics, University of Ottawa, Ottawa, ON (Canada); Masson, Denis; Riel, Bruno; Fafard, Simon [Cyrium Technologies Inc., Ottawa, ON (Canada); Jaouad, Abdelatif; Turala, Artur; Ares, Richard; Aimez, Vincent [Centre de Recherche en Nanofabrication et en Nanocaracterisation CRN2, Universite de Sherbrooke, Sherbrooke, QC (Canada)

    2010-10-14T23:59:59.000Z

    The following four TJ designs, AlGaAs/AlGaAs, GaAs/GaAs, AlGaAs/InGaP and AlGaAs/GaAs are studied to determine minimum doping concentration to achieve a resistance of <10{sup -4} {omega}{center_dot}cm{sup 2} and a peak tunneling current suitable for MJ solar cells up to 1500-suns concentration (operating current of 21 A/cm{sup 2}). Experimentally calibrated numerical models are used to determine how the resistance changes as a function of doping concentration. The AlGaAs/GaAs TJ design is determined to require the least doping concentration to achieve the specified resistance and peak tunneling current, followed by the GaAs/GaAs, and AlGaAs/AlGaAs TJ designs. The AlGaAs/InGaP TJ design can only achieve resistances >5x10{sup -4} {omega}cm{sup 2}.

  13. n-Linear Algebra of type II

    E-Print Network [OSTI]

    W. B. Vasantha Kandasamy; Florentin Smarandache

    2009-02-01T23:59:59.000Z

    This book is a continuation of the book n-linear algebra of type I and its applications. Most of the properties that could not be derived or defined for n-linear algebra of type I is made possible in this new structure: n-linear algebra of type II which is introduced in this book. In case of n-linear algebra of type II we are in a position to define linear functionals which is one of the marked difference between the n-vector spaces of type I and II. However all the applications mentioned in n-linear algebras of type I can be appropriately extended to n-linear algebras of type II. Another use of n-linear algebra (n-vector spaces) of type II is that when this structure is used in coding theory we can have different types of codes built over different finite fields whereas this is not possible in the case of n-vector spaces of type I. Finally in the case of n-vector spaces of type II, we can obtain n-eigen values from distinct fields; hence, the n-characteristic polynomials formed in them are in distinct different fields. An attractive feature of this book is that the authors have suggested 120 problems for the reader to pursue in order to understand this new notion. This book has three chapters. In the first chapter the notion of n-vector spaces of type II are introduced. This chapter gives over 50 theorems. Chapter two introduces the notion of n-inner product vector spaces of type II, n-bilinear forms and n-linear functionals. The final chapter suggests over a hundred problems. It is important that the reader is well-versed not only with linear algebra but also n-linear algebra of type I.

  14. A Vision-based Method for On-Road Truck Height Measurement in Proactive Prevention of 2 Collision with Overpasses and Tunnels

    E-Print Network [OSTI]

    Dai, Fei; Park, Man-Woo; Sandidge, Matthew; Brilakis, Ioannis

    2014-11-26T23:59:59.000Z

    and Tunnels 2 Fei Dai a, Man-Woo Park b,*, Matthew Sandidge c, and Ioannis Brilakis d 3 a Department of Civil and Environmental Engineering, West Virginia University, 635 Engineering 4 Sciences Building, 395 Evansdale Drive, Morgantown, WV 26506, USA, Email... and luggage handling in airports. 473 474 6. Acknowledgement 475 This material is based upon work supported by West Virginia University, Myongji University, and 476 University of Cambridge. Any opinions, findings, and conclusions or recommendations...

  15. Phase-locking of an InP/InGaP/InGaAs resonant tunneling diode relaxation oscillator by direct optical injection

    E-Print Network [OSTI]

    Eisenstein, Gadi

    Phase-locking of an InP/InGaP/InGaAs resonant tunneling diode relaxation oscillator by direct relaxation oscillator is demonstrated. The diode is an Al-free InP/InGaP/InGaAs structure in the InP/InGaAs/InGaP aluminum-free material system, following the work of Cohen and Ritter [6

  16. Magnetic properties of epitaxial Fe{sub 3}O{sub 4} films with various crystal orientations and tunnel magnetoresistance effect at room temperature

    SciTech Connect (OSTI)

    Nagahama, Taro, E-mail: nagahama@eng.hokudai.ac.jp; Matsuda, Yuya; Tate, Kazuya; Kawai, Tomohiro; Takahashi, Nozomi; Hiratani, Shungo; Watanabe, Yusuke; Yanase, Takashi; Shimada, Toshihiro [Graduate School of Engineering, Hokkaido University, Kita13 Nishi8, Kitak-ku, Sapporo 060-8628 (Japan)

    2014-09-08T23:59:59.000Z

    Fe{sub 3}O{sub 4} is a ferrimagnetic spinel ferrite that exhibits electric conductivity at room temperature (RT). Although the material has been predicted to be a half metal according to ab-initio calculations, magnetic tunnel junctions (MTJs) with Fe{sub 3}O{sub 4} electrodes have demonstrated a small tunnel magnetoresistance (TMR) effect. Not even the sign of the tunnel magnetoresistance ratio has been experimentally established. Here, we report on the magnetic properties of epitaxial Fe{sub 3}O{sub 4} films with various crystal orientations. The films exhibited apparent crystal orientation dependence on hysteresis curves. In particular, Fe{sub 3}O{sub 4}(110) films exhibited in-plane uniaxial magnetic anisotropy. With respect to the squareness of hysteresis, Fe{sub 3}O{sub 4} (111) demonstrated the largest squareness. Furthermore, we fabricated MTJs with Fe{sub 3}O{sub 4}(110) electrodes and obtained a TMR effect of ?12% at RT. The negative TMR ratio corresponded to the negative spin polarization of Fe{sub 3}O{sub 4} predicted from band calculations.

  17. STORAGE OPERATORS and -POSITIVE TYPES in TTR TYPE Karim NOUR 1

    E-Print Network [OSTI]

    Nour, Karim

    STORAGE OPERATORS and -POSITIVE TYPES in TTR TYPE SYSTEM Karim NOUR 1 LAMA - Equipe de Logique the notion of storage operator to simulate "call by value" in the "call by name" strategy. J.L. Krivine has for the storage operators in AF2 type system. This paper studies the -positive types (the universal second order

  18. Process For Direct Integration Of A Thin-Film Silicon P-N Junction Diode With A Magnetic Tunnel Junction

    DOE Patents [OSTI]

    Toet, Daniel (Mountain View, CA); Sigmon, Thomas W. (Albuquerque, NM)

    2005-08-23T23:59:59.000Z

    A process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction for use in advanced magnetic random access memory (MRAM) cells for high performance, non-volatile memory arrays. The process is based on pulsed laser processing for the fabrication of vertical polycrystalline silicon electronic device structures, in particular p-n junction diodes, on films of metals deposited onto low temperature-substrates such as ceramics, dielectrics, glass, or polymers. The process preserves underlayers and structures onto which the devices are typically deposited, such as silicon integrated circuits. The process involves the low temperature deposition of at least one layer of silicon, either in an amorphous or a polycrystalline phase on a metal layer. Dopants may be introduced in the silicon film during or after deposition. The film is then irradiated with short pulse laser energy that is efficiently absorbed in the silicon, which results in the crystallization of the film and simultaneously in the activation of the dopants via ultrafast melting and solidification. The silicon film can be patterned either before or after crystallization.

  19. Process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction

    DOE Patents [OSTI]

    Toet, Daniel (Mountain View, CA); Sigmon, Thomas W. (Albuquerque, NM)

    2003-01-01T23:59:59.000Z

    A process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction for use in advanced magnetic random access memory (MRAM) cells for high performance, non-volatile memory arrays. The process is based on pulsed laser processing for the fabrication of vertical polycrystalline silicon electronic device structures, in particular p-n junction diodes, on films of metals deposited onto low temperature-substrates such as ceramics, dielectrics, glass, or polymers. The process preserves underlayers and structures onto which the devices are typically deposited, such as silicon integrated circuits. The process involves the low temperature deposition of at least one layer of silicon, either in an amorphous or a polycrystalline phase on a metal layer. Dopants may be introduced in the silicon film during or after deposition. The film is then irradiated with short pulse laser energy that is efficiently absorbed in the silicon, which results in the crystallization of the film and simultaneously in the activation of the dopants via ultrafast melting and solidification. The silicon film can be patterned either before or after crystallization.

  20. Process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction

    DOE Patents [OSTI]

    Toet, Daniel; Sigmon, Thomas W.

    2004-12-07T23:59:59.000Z

    A process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction for use in advanced magnetic random access memory (MRAM) cells for high performance, non-volatile memory arrays. The process is based on pulsed laser processing for the fabrication of vertical polycrystalline silicon electronic device structures, in particular p-n junction diodes, on films of metals deposited onto low temperature-substrates such as ceramics, dielectrics, glass, or polymers. The process preserves underlayers and structures onto which the devices are typically deposited, such as silicon integrated circuits. The process involves the low temperature deposition of at least one layer of silicon, either in an amorphous or a polycrystalline phase on a metal layer. Dopants may be introduced in the silicon film during or after deposition. The film is then irradiated with short pulse laser energy that is efficiently absorbed in the silicon, which results in the crystallization of the film and simultaneously in the activation of the dopants via ultrafast melting and solidification. The silicon film can be patterned either before or after crystallization.