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1

Pulses inside the pulse mode of operation at RF Gun  

E-Print Network (OSTI)

Pulses inside the pulse mode of operation at RF Gun V. Vogel, V. Ayvazyan, K. Floettmann, D. Lipka a PiP mode of operation at RF Gun · What we need, to operate FLASH in the PiP mode · PiP study-Universitaet Bochum) Alternative: SC GUN DC GUN Cold GUN in PiP mode Cold Traveling wave GUN Why we need a PiP mode

2

Study of the Glauber correlation functions in a pulsed mode  

Science Journals Connector (OSTI)

A method for measuring the Glauber correlation functions in a pulsed mode is proposed. The effect of the detector dead time on the shape of a measured correlation function is analyzed. The second-order intensi...

I. N. Agafonov; T. Sh. Iskhakov; M. V. Chekhova

2007-07-01T23:59:59.000Z

3

Control and generation of localized pulses in passively mode-locked semiconductor lasers  

E-Print Network (OSTI)

We show experimentally and theoretically that localized pulses can be generated from an electrically biased $200\\,\\mu$m multi-transverse mode Vertical-Cavity Surface-Emitting Laser. The device is passively mode-locked using optical feedback from a distant Resonant Saturable Absorber Mirror and it is operated below threshold. We observe multistability between the off solution and a large variety of pulsating solutions with different number and arrangements of pulses per round-trip, thus indicating that the mode-locked pulses are localized, i.e. mutually independent. We show that a modulation of the bias current allows controlling the number of the pulses travelling within the cavity, thus suggesting that our system can be operated as an arbitrary pattern generator of 10 ps pulses and 1 W peak power.

Marconi, M; Camelin, P; Chaparro, D; Balle, S; Giudici, M

2015-01-01T23:59:59.000Z

4

Graphene mode-locked Cr:ZnS laser with 41 fs pulse duration  

Science Journals Connector (OSTI)

We report the ultrashort-pulse Cr:ZnS laser mode-locked by graphene-based saturable absorber mirror. Using the combination of bulk material and a chirped mirror, we demonstrate the...

Tolstik, Nikolai; Sorokin, Evgeni; Sorokina, Irina T

2014-01-01T23:59:59.000Z

5

Cladding-pumped passively mode-locked fiber laser generating femtosecond and picosecond pulses  

Science Journals Connector (OSTI)

Passively mode-locked fiber lasers cladding pumped by broad-area diode-laser arrays are described. With a dispersion-compenstated erbiumytterbium fiber oscillator, 200-fs pulses with...

Fermann, M E; Minelly, J D; Vienne, G G; Harter, D

1996-01-01T23:59:59.000Z

6

Modes in a pulse-modulated radio-frequency dielectric-barrier glow discharge  

SciTech Connect

This letter reports an experimental study of a pulse-modulated radio-frequency dielectric-barrier discharge in atmospheric helium. By controlling the duty cycle at a modulation frequency of 10 and 100 kHz, the 13.56 MHz discharge is shown to operate in three different glow modes: the continuum mode, the discrete mode, and the transition mode. By investigating plasma ignition, residual electrons during power off are found to affect different glow modes. Duty cycle dependences of power density, gas temperature, optical emission intensities at 706 and 777 nm are used to capture clearly the characteristics of the three glow modes.

Shi, J. J.; Zhang, J.; Qiu, G. [College of Science, Donghua University, Shanghai 201620 (China); Walsh, J. L.; Kong, M. G. [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)

2008-07-28T23:59:59.000Z

7

Modes in a pulse-modulated radio-frequency dielectric-barrier glow discharge  

Science Journals Connector (OSTI)

This letter reports an experimental study of a pulse-modulated radio-frequency dielectric-barrier discharge in atmospheric helium. By controlling the duty cycle at a modulation frequency of 10 and 100 kHz the 13.56 MHz discharge is shown to operate in three different glow modes: the continuum mode the discrete mode and the transition mode. By investigating plasma ignition residual electrons during power off are found to affect different glow modes. Duty cycle dependences of power density gas temperature optical emission intensities at 706 and 777 nm are used to capture clearly the characteristics of the three glow modes.

J. J. Shi; J. Zhang; G. Qiu; J. L. Walsh; M. G. Kong

2008-01-01T23:59:59.000Z

8

Synchronization of InP Colliding Pulse Mode Locked Laser by Electrical Subharmonic Modulation  

E-Print Network (OSTI)

to an InP-InGaAsP wafer. The CPM laser includes a saturable absorber (SA) placed in the middle of the laser-short pulses without self- pulsing commonly seen in regular mode locked lasers [1-2,4]. The MOCVD grown InP-InGaAsP deeper into absorption saturation for more stable and effective pulse-shaping for generating ultra

Kolner, Brian H.

9

All-Fiber Pulsed Lasers Passively Mode-Locked by Transferable Vertically Aligned Carbon Nanotube Film  

E-Print Network (OSTI)

All-Fiber Pulsed Lasers Passively Mode-Locked by Transferable Vertically Aligned Carbon Nanotube of Tokyo, Tokyo 113-8656, Japan An all-fiber passive laser mode locking is realized with a vertically aligned single-walled carbon nanotube film that can be transferred onto an arbitrary substrate using only

Maruyama, Shigeo

10

Electron cyclotron resonance plasma production by using pulse mode microwaves and dependences of ion beam current and plasma parameters on the pulse condition  

SciTech Connect

We measure the ion beam current and the plasma parameters by using the pulse mode microwave operation in the first stage of a tandem type ECRIS. The time averaged extracted ion beam current in the pulse mode operation is larger than that of the cw mode operation with the same averaged microwave power. The electron density n{sub e} in the pulse mode is higher and the electron temperature T{sub e} is lower than those of the cw mode operation. These plasma parameters are considered to cause in the increase of the ion beam current and are suitable to produce molecular or cluster ions.

Kiriyama, Ryutaro; Takenaka, Tomoya; Kurisu, Yousuke; Nozaki, Dai; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki [Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan)

2012-02-15T23:59:59.000Z

11

Design and optimization of 6li neutron-capture pulse mode ion chamber  

E-Print Network (OSTI)

The purpose of this research is to design and optimize the performance of a unique, inexpensive 6Li neutron-capture pulse-mode ion chamber (LiPMIC) for neutron detection that overcomes the fill-gas contamination stemming from outgas of detector...

Chung, Kiwhan

2009-05-15T23:59:59.000Z

12

Transition dynamics for multi-pulsing in mode-locked lasers  

E-Print Network (OSTI)

laser," Opt. Lett. 23, 123-125 (1998). 5. M. E. Fermann and J. D. Minelly, "Cladding-pumped passiveTransition dynamics for multi-pulsing in mode-locked lasers Brandon G. Bale1, Khanh Kieu2, J.bale@aston.ac.uk Abstract: We consider experimentally and theoretically a refined parameter space in a laser system near

Kieu, Khanh

13

Enhanced production of ECR plasma by using pulse mode microwaves on a large bore ECRIS with permanent magnets  

SciTech Connect

In order to enhance the efficiency of an electron cyclotron resonance (ECR) plasma for a broad and dense ion beam source at low pressure, the magnetic field configuration is constructed by all permanent magnets. By using the pulse mode, we aim at the generation of plasma with parameters that cannot be achieved in the CW mode at microwave frequencies of 11-13GHz, under the constraint of the same average incident microwave powers. It is found that the total beam currents are increased by the pulse mode operation compared with the case of the CW mode. According to probe measurements of the ECR plasma, it is found that the electron density in the pulse mode is larger than that in the CW mode, while the electron temperatures in the pulse mode are lower than that in the CW mode. These results are discussed from the viewpoint of relaxation times obtained on plasma parameters and ECR efficiency. The cause of the beam current increment and operational windows spread due to the pulse mode are also discussed on these parameters suitable to production of molecular/cluster ions.

Kato, Yushi; Kiriyama, Ryutaro; Takenaka, Tomoya; Kurisu, Yosuke; Nozaki, Dai; Yano, Keisuke; Sato, Fuminobu; Iida, Toshiyuki [Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka Univ., 2-1 Ymadaoka, Suita-shi, Osaka, 565-0871 (Japan)

2012-11-06T23:59:59.000Z

14

Ultrashort-pulse generation in excimer lasers by fast mode locking using electrooptic deflector  

SciTech Connect

A novel method for ultrashort-pulse (USP) generation in excimer lasers employing fast mode locking with the use of an electrooptic deflector (EOD) is investigated numerically. In this method, a USP is formed by a train of very short high-contrast-ratio transmission windows produced in a cavity by a modulator composed of an EOD and a diaphragm. The potential of this method and fundamental properties of USP generation with its use are demonstrated taking a KrF laser as an example. It is shown that the application of the EOD driven with both sine and square wave of voltage enables one to obtain high-contrast-ratio light pulses of duration in the range 1--10 ps at the gain duration of only 50--100 ns. The pulses produced with this method are two orders of magnitude shorter than those attainable with conventional mode locking. The method is capable of being an efficient way for USP generation also in other short-gain-duration lasers.

Badziak, J.; Jablonski, S. [Inst. of Plasma Physics and Laser Microfusion, Warsaw (Poland)] [Inst. of Plasma Physics and Laser Microfusion, Warsaw (Poland)

1997-03-01T23:59:59.000Z

15

Operation of terahertz quantum-cascade lasers at 164 K in pulsed mode and at 117 K in continuous-wave mode.  

SciTech Connect

We report the demonstration of a terahertz quantum-cascade laser that operates up to 164 K in pulsed mode and 117 K in continuous-wave mode at approximately 3.0 THz. The active region was based on a resonant-phonon depopulation scheme and a metal-metal waveguide was used for modal confinement. Copper to copper thermocompression wafer bonding was used to fabricate the waveguide, which displayed improved thermal properties compared to a previous indium-gold bonding method.

Kumar, Sushil (Massachusetts Institute of Technology, Cambridge, MA); Williams, Benjamin S. (Massachusetts Institute of Technology, Cambridge, MA); Hu, Qing (Massachusetts Institute of Technology, Cambridge, MA); Reno, John Louis

2005-04-01T23:59:59.000Z

16

Role of locked mode in the effectiveness of pulsed poloidal current drive regime in the reversed-field pinch  

SciTech Connect

The close relationship between the locked mode (LM) and pulsed poloidal current drive (PPCD) regime in a reversed-field pinch device is described. If the modes lock close to the shell gap then the LM is enhanced and there is a high probability that the PPCD will not improve plasma performance. The physical reason will be discussed. If the position of the locked mode is far from the shell gap then the PPCD is effective with a high probability. LM energy is reduced and the more the LM energy decreases, the better the plasma performance.

Frassinetti, L.; Yagi, Y.; Koguchi, H.; Shimada, T.; Hirano, Y.; Sakakita, H. [National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

2005-10-01T23:59:59.000Z

17

Numerical and simulation study of terahertz radiation generation by laser pulses propagating in the extraordinary mode in magnetized plasma  

SciTech Connect

A one-dimensional numerical model for studying terahertz radiation generation by intense laser pulses propagating, in the extraordinary mode, through magnetized plasma has been presented. The direction of the static external magnetic field is perpendicular to the polarization as well as propagation direction of the laser pulse. A transverse electromagnetic wave with frequency in the terahertz range is generated due to the presence of the magnetic field. Further, two-dimensional simulations using XOOPIC code show that the THz fields generated in plasma are transmitted into vacuum. The fields obtained via simulation study are found to be compatible with those obtained from the numerical model.

Jha, Pallavi; Kumar Verma, Nirmal [Department of Physics, University of Lucknow, Lucknow-226007 (India)

2014-06-15T23:59:59.000Z

18

Abnormal electron-heating mode and formation of secondary-energetic electrons in pulsed microwave-frequency atmospheric microplasmas  

SciTech Connect

The formation of secondary energetic electrons induced by an abnormal electron-heating mode in pulsed microwave-frequency atmospheric microplasmas was investigated using particle-in-cell simulation. We found that additional high electron heating only occurs during the first period of the ignition phase after the start of a second pulse at sub-millimeter dimensions. During this period, the electrons are unable to follow the abruptly retreating sheath through diffusion alone. Thus, a self-consistent electric field is induced to drive the electrons toward the electrode. These behaviors result in an abnormal electron-heating mode that produces high-energy electrons at the electrode with energies greater than 50?eV.

Kwon, H. C. [Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of) [Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Research and Development Division, SK Hynix Semiconductor Inc., Icheon 467-701 (Korea, Republic of); Jung, S. Y. [Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of)] [Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Kim, H. Y.; Won, I. H.; Lee, J. K., E-mail: jkl@postech.ac.kr [Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

2014-03-15T23:59:59.000Z

19

Eye-safe single-frequency single-mode polarized all-fiber pulsed laser with peak power of 361??W  

Science Journals Connector (OSTI)

An all-fiber, single-frequency, single-mode linearly polarized, high peak power pulsed laser at 1540nm for coherent Doppler wind lidar is demonstrated. A narrow-linewidth seed...

Zhang, Xin; Diao, Weifeng; Liu, Yuan; Zhu, Xiaopeng; Yang, Yan; Liu, Jiqiao; Hou, Xia; Chen, Weibiao

2014-01-01T23:59:59.000Z

20

Omega?to?the?one?third term in dispersion relation for acoustic pulse propagation through turbulence  

Science Journals Connector (OSTI)

The authors earlier formulation of pulse propagation through turbulence required a somewhat ad hoc separation of the effects of large scale and small scale turbulence with the selection of a cut?off turbulentwave number k c that separates the two regimes. A neater?cleaner formulation proceeds with the premise that the frequency dispersion of pulses is caused by that part of the turbulence spectrum which lies in the inertial range originally predicted by Kolmogoroff. The acoustic propagating waves dispersion relation has the acoustic wave number being of the form k=(?/c)+F(?) where c is a spatially averaged sound speed and where for mechanical turbulence the extra term F(?) must depend on only the angular frequency ? the sound speedc and the turbulent energy dissipation ? per unit fluid mass and per unit time. If the turbulence is weak then the quantity F(?) has to be of second order in the portions of the turbulent fluid velocity in the intertial range so following Kolmogoroffs reasoning it must vary with ? as ?2/3. Simple dimensional analysis then reveals that F(?) is K?2/3 c ?7/3?1/3 the latter factor being as announced in the title of this abstract and K being a universal dimensionless complex constant. A similar result holds for thermal turbulence. The analysis showing that the separating?out of the effects of turbulence in the inertial regime is in fact possible yields K=?0.37e i?/3. The dispersion is typically small but has an accumulative effect that leads to a sizable pulse distortion over large propagation distances. [Work supported by NASA Langley Research Center.

Allan D. Pierce

1995-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Free Energy and Specific Heat in Ferroelectric Phase Transition in Terms of a Single-Mode Anharmonic Oscillator Model  

Science Journals Connector (OSTI)

...Copyright (c) 1971 Progress of Theoretical Physics March 1971 letter Letters to the Editor Free Energy and Specific Heat in Ferroelectric Phase Transition in Terms of a Single-Mode Anharmonic Oscillator Model Yositaka Onodera Department......

Yositaka Onodera

1971-03-01T23:59:59.000Z

22

Free Energy and Specific Heat in Ferroelectric Phase Transition in Terms of a Single-Mode Anharmonic Oscillator Model  

Science Journals Connector (OSTI)

...Copyright (c) 1976 Progress of Theoretical Physics March 1976 correction Errata Free Energy and Specific Heat in Ferroelectric Phase Transition in Terms of a Single-Mode Anharmonic Oscillator Model Yositaka Onodera The......

Yositaka Onodera

1976-03-01T23:59:59.000Z

23

High-frequency acousto-optic mode locker for picosecond pulse generation  

Science Journals Connector (OSTI)

We modeled, designed, and built a 500-MHz acousto-optic mode locker with a diffraction efficiency of 28% per 1 W drive power. The transducer is zinc oxide sputtered onto a sapphire...

Keller, U; Weingarten, K J; Gerstenberger, D C; Li, K D; Khuri-Yakub, B T; Bloom, D M

1990-01-01T23:59:59.000Z

24

Final Technical Progress Report Long term risk from actinides in the environment: Modes of mobility  

SciTech Connect

The key source of uncertainty in assessing actinide mobility is the relative importance of transport by: (1) wind erosion, (2) water erosion, and (3) vertical migration. Each of these three processes depends on several environmental factors and they compete with one another. A scientific assessment of the long-term risks associated with actinides in surface soils depends on better quantifying each of these three modes of mobility. The objective from our EMSP study was to quantify the mobility of soil actinides by wind erosion, water erosion, and vertical migration at three semiarid sites where actinide mobility is a key technical, social and legal issue. This EMSP project was the first to evaluate all three factors at a site. The approach has been to investigate both short- and long-term issues based on field and lab studies and model comparisons. Our results demonstrate the importance of incorporating threshold responses into a modeling framework that accounts for environmental factors and natural disturbances that trigger large changes in actinide mobility. The study measured erosional losses of sediment and fallout cesium (an actinide analogue) from field plots located near WIPP in 1998. The results highlight the large effect of burning as a disturbance on contaminant transport and mobility via runoff and erosion. The results show that runoff, erosion, and actinide transport are (1) strongly site specific-differences in radionuclide transport between WIPP and Rocky Flats differed by a factor of twelve because of soil and vegetation differences, and (2) are strongly impacted by disturbances such as fire, which can increase runoff, erosion, and actinide transport by more than an order of magnitude. In addition, a laboratory experiment using soil columns was conducted to investigate the vertical transport of contaminants in sandy soils. Nine columns of soil collected from the vicinity of the WIPP site were prepared. The column consisted of a piece of PVC pipe 20 cm in diameter and approximately 22 cm long. A thin ''marker layer'' of white soil was added to the top of each column followed by a thin layer of soil that had been spiked with 137Cs, cerium and lanthanum was applied to the surface. Approximately 900 cm of water (the equivalent of about 30 years of rainfall) was then applied at a rate of 3.2 L d-1. All of the activity contained in the soil core appeared to be in the top few mm of soil, i.e. there was virtually no movement of the 134Cs labeled particles. Finally, a library of object-oriented model components was created using Visual Basic to support the construction of contaminant transport models. These components greatly simplify the task of building 1- to 3- dimensional simulation models for risk assessment. The model components created under this funding were subsequently applied to help answer questions regarding risks from irrigation associated with potential releases from the Yucca Mountain waste repository.

Thomas B. Kirchner

2002-03-22T23:59:59.000Z

25

Long-Term Safety of Pulsed Irrigation Evacuation (PIE) Use with Chronic Bowel Conditions  

Science Journals Connector (OSTI)

We wanted to determine the long-term effects ofpulsed irrigation evacuation on the colon.Sigmoidoscopy/colonoscopy was performed on four patientswith spinal cord injuries who have used this procedure an averag...

Terry Gramlich; Terry Puet

26

Microsoft PowerPoint - Arseneau_EIA_ShortTermDriversofEnergyPrices.ppt [Compatibility Mode]  

U.S. Energy Information Administration (EIA) Indexed Site

SHORT-TERM ENERGY PRICES: SHORT-TERM ENERGY PRICES: WHAT DRIVERS MATTER MOST? DAVID M. ARSENEAU FEDERAL RESERVE BOARD U.S. Energy Information Administration & Johns Hopkins University - SAIS FEDERAL RESERVE BOARD Johns Hopkins University SAIS 2010 Energy Conference Washington, D.C., U.S.A. A il 6 2010 April 6, 2010 BROAD COMMODITY PRICES SINCE 2000 Short-term Energy Prices: What Drivers Matters Most? BROAD COMMODITY PRICES SINCE 2000 April 6, 2010 Seminar: 2010 EIA/SAIS Energy Conference 2 A (GROSSLY OVERSIMPLIFIED) FRAMEWORK Short-term Energy Prices: What Drivers Matters Most? A (GROSSLY OVERSIMPLIFIED) FRAMEWORK ...  Two candidate explanations:  "Fundamentals"  Fundamentals  Trend price movements appear broadly interpretable through lens of fundamental market developments...

27

Long-term risk from actinides in the environment: Modes of mobility. 1998 annual progress report  

SciTech Connect

'The mobility of actinides in surface soils is a key issue of concern at several DOE facilities in arid and semiarid environments, including Rocky Flats, Hanford, Nevada Test Site, Idaho National Engineering Laboratory, and Los Alamos National Laboratory and the Waste Isolation Pilot Plant (WIPP). Key sources of uncertainty in assessing Pu mobility are the magnitudes of mobility resulting from three modes of transport: (1) wind erosion, (2) water erosion, and (3) vertical migration. Each of these three processes depend on numerous environmental factors and they compete with one another, particularly for actinides in very shallow soils ({approximately} 1 \\265m). The overall goal of the study is to quantify the mobility of soil actinides from all three modes. The authors study is using field measurements, laboratory experiments, and ecological modeling to address these three processes at three DOE facilities where actinide kinetics are of concern: WIPP, Rocky Flats, and Hanford. Wind erosion is being measured with suite of monitoring equipment, water erosion is being studied with rainfall simulation experiments, vertical migration is being studied in controlled laboratory experiments, and the three processes are being integrated using ecological modeling. Estimates for clean up of soil actinides for the extensive tracts of DOE land range to hundreds of billion $ in the US Without studies of these processes, unnecessary clean-up of these areas may waste billions of dollars and cause irreparable ecological damage through the soil removal. Further, the outcomes of litigation against DOE are dependent on quantifying the mobility of actinides in surface soils. This report provides a summary of work for the first year of a 3-year project; subcontracts to collaborating institutions (Colorado State University and New Mexico State University) were not in place until late December 1997, and hence this report focuses on the results of the 5 months from January through May 1998. The major result to date is a review of literature on the potential for using soil concentrations of {sup 137}Cs and {sup 241}Am as tracers for plutonium in soil. Measurements of {sup 239}Pu contamination in the environment are expensive and time consuming, requiring radiochemical analysis and alpha spectroscopy. They evaluated the literature for measurements of {sup 137}Cs and {sup 241}Am, both of which are more cost-effectively measured by gamma spectrometry, as tracers for Pu in soil. Their results indicate that: significant positive correlation exists between Pu, Cs, and Am in soils and sediments at several locations including Rocky Flats, Los Alamos, and Hanford; atmospheric transport of Pu and Cs from worldwide fallout is essentially the same; the attachment of Pu and Cs to soil particles of various size is very similar; both Pu and Cs movement in the environment correlate well with soil and sediment particle movements; a significant correlation between Pu, Cs, and Am was found in soil as a function of depth, indicating similar vertical migration behavior (most of the activity of these radionuclides is confined to the top 10--20 cm of soil at virtually all locations); most Pu and Cs are strongly absorbed onto clay and organic matter in soils and there is essentially very little leaching of Pu, Am and Cs through soil columns. Based on the above information, they believe that {sup 137}Cs and {sup 241}Am are excellent tracers for both {sup 239}Pu and soil particle transport processes in clay, mineral bearing and/or organic soils. Therefore, Cs and Am would be good tracers for the proposed water erosion and vertical migration work, at least for both Rocky Flats and Hanford. The correlation between Pu and Cs may not be as strong in sandy soil (e.g. WIPP site), however, examination of more data is needed.'

Breshears, D.D.; Whicker, J.J. [Los Alamos National Lab., NM (US); Ibrahim, S.A.; Whicker, F.W.; Hakonson, T.E. [Colorado State Univ., Fort Collins, CO (US); Kirchner, T. [New Mexico State Univ., Las Cruces, NM (US)

1998-06-01T23:59:59.000Z

28

Long-Term Monitoring of Polarization-Mode Dispersion of Aerial Optical Cables With Respect to Line Availability  

Science Journals Connector (OSTI)

Physical and technical limits become important when trying to increase data transfer rates to tens of gigabits and higher for already installed optical cables. Polarization-mode...

Nellen, Philipp M; Brnnimann, Rolf; Held, Marcel; Sennhauser, Urs

2004-01-01T23:59:59.000Z

29

The Theta Laser A Low Noise Chirped Pulse Laser  

E-Print Network (OSTI)

The Theta Laser A Low Noise Chirped Pulse Laser Dimitrios Mandridis dmandrid@creol.ucf.edu April 29, 2011 CREOL Affiliates Day 2011 #12;2 Objective: Frequency Swept (FM) Mode-locked Laser · Develop a frequency swept laser, · linear f-sweep, · uniform-intensity, · low noise, · with long-term stability

Van Stryland, Eric

30

Comparison of a quantum cascade laser used in both cw and pulsed modes. Application to the study of SO2 lines around 9?m  

Science Journals Connector (OSTI)

The same quantum cascade laser spectrometer working around 9?m was used ... modes to compare their own characteristics. The laser emitting in continuous-wave mode was mainly...2...ro-vibrational lines. This work...

B. Grouiez; B. Parvitte; L. Joly; D. Courtois; V. Zeninari

2008-02-01T23:59:59.000Z

31

Analysis and experimental study on formation conditions of large-scale barrier-free diffuse atmospheric pressure air plasmas in repetitive pulse mode  

SciTech Connect

Atmospheric air diffuse plasmas have enormous application potential in various fields of science and technology. Without dielectric barrier, generating large-scale air diffuse plasmas is always a challenging issue. This paper discusses and analyses the formation mechanism of cold homogenous plasma. It is proposed that generating stable diffuse atmospheric plasmas in open air should meet the three conditions: high transient power with low average power, excitation in low average E-field with locally high E-field region, and multiple overlapping electron avalanches. Accordingly, an experimental configuration of generating large-scale barrier-free diffuse air plasmas is designed. Based on runaway electron theory, a low duty-ratio, high voltage repetitive nanosecond pulse generator is chosen as a discharge excitation source. Using the wire-electrodes with small curvature radius, the gaps with highly non-uniform E-field are structured. Experimental results show that the volume-scaleable, barrier-free, homogeneous air non-thermal plasmas have been obtained between the gap spacing with the copper-wire electrodes. The area of air cold plasmas has been up to hundreds of square centimeters. The proposed formation conditions of large-scale barrier-free diffuse air plasmas are proved to be reasonable and feasible.

Li, Lee, E-mail: leeli@mail.hust.edu.cn; Liu, Lun; Liu, Yun-Long; Bin, Yu; Ge, Ya-Feng; Lin, Fo-Chang [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electric and Electronic Engineering, HuaZhong University of Science and Technology (HUST), Wuhan 430074 (China)

2014-01-14T23:59:59.000Z

32

Pulsed-neutron monochromator  

DOE Patents (OSTI)

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The waves are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

Mook, H.A. Jr.

1984-01-01T23:59:59.000Z

33

Pulsed-neutron monochromator  

DOE Patents (OSTI)

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The wave are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

Mook, Jr., Herbert A. (Oak Ridge, TN)

1985-01-01T23:59:59.000Z

34

Pickup for pulse NMR spectrometer  

SciTech Connect

This paper describes a single-coil pickup for a pulse NMR spectrometer. The pickup is alternately connected by rf diode switches to the transmitter (in transmit mode) and to the receiver (in receive mode). The dead time of a receiver with this pickup is less than or equal to 10 usec.

Zaitsev, V.N.; Podsekin, A.K.

1985-01-01T23:59:59.000Z

35

Efficient, high-speed ablation of soft tissue with few-microjoule, femtosecond pulse bursts  

E-Print Network (OSTI)

Femtosecond pulses hold great promise for high-precision tissue removal. However, ablation rates are severely limited by the need to keep average laser power low to avoid collateral damage due to heat accumulation. Furthermore, previously reported pulse energies preclude delivery in flexible fibers, hindering in vivo operation. Both of these problems can be addressed through use of groups of high-repetition-rate pulses, or bursts. Here, we report a novel fiber laser and demonstrate ultrafast burst-mode ablation of brain tissue at rates approaching 1 mm$^3$/min, an order of magnitude improvement over previous reports. Burst mode operation is shown to be superior in terms of energy required and avoidance of thermal effects, compared to uniform repetition rates. These results can pave the way to in vivo operation at medically relevant speeds, delivered via flexible fibers to surgically hard-to-reach targets, or with simultaneous magnetic resonance imaging.

Kerse, Can; Kalayc?o?lu, Hamit; A??k, Mehmet D; Akaalan, nder; Ilday, F mer

2014-01-01T23:59:59.000Z

36

Single-cycle radio-frequency pulse generation by an optoelectronic  

E-Print Network (OSTI)

Single-cycle radio-frequency pulse generation by an optoelectronic oscillator Etgar C. Levy,1-locking of an optoelectronic oscillator which generates a single-cycle radio-frequency pulse train. The measured pulse to pulse by a passive mode-locked oscillator. The passive mode-locked optoelectronic oscillator is important

Horowitz, Moshe

37

Pulse combustion  

Science Journals Connector (OSTI)

Pulse combustion has been gaining increased interest because of its potential for higher combustion efficiency greater combustion intensity and lower pollutant emissions. Unsteady combustion causes increased mass momentum and heat transfer. As a result reactants mix faster heat release is accelerated and heat transfer is enhanced in unsteady reacting flows. Many of these phenomena were discovered long ago by engineers looking for the cause of often detrimental combustion instabilities. Much more recently some of these enhanced transfer properties have been used to design efficient and compact pulse combustors. Although to date successful commercialization on a large scale has been limited to home heating units (e.g. the Lenox Pulse Furnace) highly efficient pulse spray dryers (Bepex Unison Dryer) pulse calciners and pulse waste incinerators have been designed. Pulsations have also been applied to carbon black fluidized bed gasifiers. Not all these designs will become economically viable. However the development of tunable pulse combustors that can be acoustically matched to the changing resonance frequency of these pulse processes have made many of them more promising. Recent findings that pulsation can enhance burning even in turbulent flows lend further encouragement to the developers of novel pulse combustion devices.

Jechiel I. Jagoda

2000-01-01T23:59:59.000Z

38

Properties of dielectric-barrier-free atmospheric pressure microplasma driven by submicrosecond dc pulse voltage  

SciTech Connect

Atmospheric pressure microplasma driven by dc pulse is developed. This device has a simple structure comprised of a flowing helium (He) feed gas and dielectric-free metal electrodes without an external current limiting resistor. It is shown that a stable glow mode plasma can be sustained without arc runaway by limiting the voltage pulse width to shorter than 300 ns. The properties of the device are reported in terms of discharge current waveforms, rotational temperature of N{sub 2}{sup +}, and spatiotemporally resolved optical emission characteristics.

Ha, Chang-Seung; Choi, Joon-Young; Kim, Dong-Hyun; Park, Chung-Hoo; Lee, Hae June; Lee, Ho-Jun [Department of Electrical Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)

2009-08-10T23:59:59.000Z

39

The Homopolar Pulse Billet Heating Process  

E-Print Network (OSTI)

The use of homopolar generators operated in the pulse mode to heat forging billets offers several possible advantages over present heating methods. Because heating is uniform throughout the entire cross section, billets can safely be heated...

Keith, R. E.; Weldon, W. F.

1982-01-01T23:59:59.000Z

40

Storage Ring Operation Modes  

NLE Websites -- All DOE Office Websites (Extended Search)

Longitudinal bunch profile and Up: APS Storage Ring Parameters Longitudinal bunch profile and Up: APS Storage Ring Parameters Previous: Source Parameter Table Storage Ring Operation Modes Standard Operating Mode, top-up Fill pattern: 102 mA in 24 singlets (single bunches) with a nominal current of 4.25 mA and a spacing of 153 nanoseconds between singlets. Lattice configuration: Low emittance lattice with effective emittance of 3.1 nm-rad and coupling of 1%. Bunch length (rms): 33.5 ps. Refill schedule: Continuous top-up with single injection pulses occurring at a minimum of two minute intervals, or a multiple of two minute intervals. Special Operating Mode - 324 bunches, non top-up Fill pattern: 102 mA in 324 uniformly spaced singlets with a nominal single bunch current of 0.31 mA and a spacing of 11.37 nanoseconds between singlets.

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Pulse stretcher  

DOE Patents (OSTI)

Apparatus (20) for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse. The apparatus (20) uses a White cell (10) having a plurality of optical delay paths (18a-18d) of successively increasing number of passes between the field mirror (13) and the objective mirrors (11 and 12). A pulse (26) from a laser (27) travels through a multi-leg reflective path (28) between a beam splitter (21) and a totally reflective mirror (24) to the laser output (37). The laser pulse (26) is also simultaneously injected through the beam splitter (21) to the input mirrors (14a-14d) of the optical delay paths (18a-18d). The pulses from the output mirrors (16a-16d) of the optical delay paths (18a-18d) go simultaneously to the laser output (37) and to the input mirrors ( 14b-14d) of the longer optical delay paths. The beam splitter (21) is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output (37).

Horton, James A. (Livermore, CA)

1994-01-01T23:59:59.000Z

42

Pulsed Laser Deposition | EMSL  

NLE Websites -- All DOE Office Websites (Extended Search)

Pulsed Laser Deposition Pulsed Laser Deposition EMSL's pulsed laser deposition (PLD) system is designed for epitaxial growth of oxide, ceramic, or synthetic mineral thin films and...

43

Pulsed hydrojet  

DOE Patents (OSTI)

An underwater pulsed hydrojet propulsion system is provided for accelerating and propelling a projectile or other vessel. A reactant, such as lithium, is fluidized and injected into a water volume. The resulting reaction produces an energy density in a time effective to form a steam pocket. Thrust flaps or baffles direct the pressure from the steam pocket toward an exit nozzle for accelerating a water volume to create thrust. A control system regulates the dispersion of reactant to control thrust characteristics.

Bohachevsky, I.O.; Torrey, M.D.

1986-06-10T23:59:59.000Z

44

Note: Emittance measurements of intense pulsed proton beam for different pulse length and repetition rate  

SciTech Connect

The high intensity ion source (SILHI), in operation at CEA-Saclay, has been used to produce a 90 mA pulsed proton beam with pulse length and repetition rates suitable for the European Spallation Source (ESS) linac. Typical r-r{sup '} rms normalized emittance values smaller than 0.2{pi} mm mrad have been measured for operation in pulsed mode (0.01 < duty cycle < 0.15 and 1 ms < pulse duration < 10 ms) that are relevant for the design update of the Linac to be used at the ESS in Lund.

Miracoli, R. [ESS Bilbao, Vizcaya (Spain); INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Gammino, S.; Celona, L.; Mascali, D. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Castro, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); Universita degli studi di Catania, Dipartimento di Fisica e Astronomia, V. S. Sofia 64, 95123 Catania (Italy); Gobin, R.; Delferriere, O.; Adroit, G.; Senee, F. [CEA-IRFU, Gif sur Yvette Cedex (France); Ciavola, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, 95123 Catania (Italy); CNAO, Str. Pr. Campeggi, Pavia (Italy)

2012-05-15T23:59:59.000Z

45

Tapered pulse tube for pulse tube refrigerators  

DOE Patents (OSTI)

Thermal insulation of the pulse tube in a pulse-tube refrigerator is maintained by optimally varying the radius of the pulse tube to suppress convective heat loss from mass flux streaming in the pulse tube. A simple cone with an optimum taper angle will often provide sufficient improvement. Alternatively, the pulse tube radius r as a function of axial position x can be shaped with r(x) such that streaming is optimally suppressed at each x.

Swift, Gregory W. (Sante Fe, NM); Olson, Jeffrey R. (San Mateo, CA)

1999-01-01T23:59:59.000Z

46

High-power pulse modulator with ignitron discharger  

SciTech Connect

The high-power pulse modulator described here is used to produce spatial gaseous discharges and has an improved, controllable charging circuit, which permits a type ITR-4 ignitron discharger to be employed in a frequency mode as the basic commutator. The modulator is utilized in two modes: at a pulse repetition frequency of 50 Hz pulses are formed that have a duration of 25 usec and energies up to 3.5 kJ and at a frequency of 200 Hz, the pulses have a duration of -2 usec and energies up to 600 J. In all conditions the modulator operated stably with a wide range of load changes.

Anisimova, T.E.; Akkuratov, E.V.; Artemov, V.A.; Gromovenko, V.M.; Kalinin, V.P.; Nikonov, V.P.

1985-10-01T23:59:59.000Z

47

Theory of passive harmonic mode-locking using waveguide arrays  

E-Print Network (OSTI)

laser," Opt. Lett. 23, 123-125 (1998). 3. M. E. Fermann and J. D. Minelly, "Cladding-pumped passive theoretical treatment is given of the phe- nomenon of harmonic mode-locking in a laser cavity mode Optical Society of America OCIS codes: (140.4050) Mode-locked lasers; (060.5530) Pulse propagation

48

Long Pulse Physics via International Stellarator Collaboration  

E-Print Network (OSTI)

Long Pulse Physics via International Stellarator Collaboration G. A. Wurden & the US stellarator University 9 ­ New York University 10 ­ Los Alamos National Laboratory #12;US Collaboration on overseas plasmas to long pulses. · Stable commitment to long term collaborations with Germany and Japan

49

Fast pulsed excitation wiggler or undulator  

DOE Patents (OSTI)

A fast pulsed excitation, electromagnetic undulator or wiggler, employing geometrically alternating substacks of thin laminations of ferromagnetic material, together with a single turn current loop excitation of the composite assembly, of such shape and configuration that intense, spatially alternating, magnetic fields are generated; for use as a pulsed mode undulator or wiggler radiator, for use in a Free Electron Laser (FEL) type radiation source or, for use in an Inverse Free Electron Laser (IFEL) charged particle accelerator.

van Steenbergen, Arie (Shoreham, NY)

1990-01-01T23:59:59.000Z

50

Techniques for increasing output power from mode-locked semiconductor lasers  

SciTech Connect

Mode-locked semiconductor lasers have drawn considerable attention as compact, reliable, and relatively inexpensive sources of short optical pulses. Advances in the design of such lasers have resulted in vast improvements in pulsewidth and noise performance, at a very wide range of repetition rates. An attractive application for these lasers would be to serve as alternatives for large benchtop laser systems such as dye lasers and solid-state lasers. However, mode-locked semiconductor lasers have not yet approached the performance of such systems in terms of output power. Different techniques for overcoming the problem of low output power from mode-locked semiconductor lasers will be discussed. Flared and arrayed lasers have been used successfully to increase the pulse saturation energy limit by increasing the gain cross section. Further improvements have been achieved by use of the MOPA configuration, which utilizes a flared semiconductor amplifier s amplify pulses to energies of 120 pJ and peak powers of nearly 30W.

Mar, A.; Vawter, G.A.

1996-02-01T23:59:59.000Z

51

Microwave and Pulsed Power  

SciTech Connect

The goals of the Microwave and Pulsed Power thrust area are to identify realizable research and development efforts and to conduct high-quality research in those pulse power and microwave technologies that support existing and emerging programmatic requirements at Lawrence Livermore National Laboratory (LLNL). Our main objective is to work on nationally important problems while enhancing our basic understanding of enabling technologies such as component design and testing, compact systems packaging, exploratory physics experiments, and advanced systems integration and performance. During FY-92, we concentrated our research efforts on the six project areas described in this report. (1) We are investigating the superior electronic and thermal properties of diamond that may make it an ideal material for a high-power, solid-state switch. (2) We are studying the feasibility of using advanced Ground Penetrating Imaging Radar technology for reliable non-destructive evaluation of bridges and other high-value concrete structures. These studies include conceptual designs, modeling, experimental verifications, and image reconstruction of simulated radar data. (3) We are exploring the efficiency of pulsed plasma processing techniques used for the removal of NO{sub x} from various effluent sources. (4) We have finished the investigation of the properties of a magnetically delayed low-pressure gas switch, which was designed here at LLNL. (5) We are applying statistical electromagnetic theory techniques to help assess microwave effects on electronic subsystems, by using a mode stirred chamber as our measurement tool. (6) We are investigating the generation of perfluoroisobutylene (PFIB) in proposed CFC replacement fluids when they are subjected to high electrical stresses and breakdown environments.

Freytag, E.K.

1993-03-01T23:59:59.000Z

52

Isolated trigger pulse generator  

DOE Patents (OSTI)

A trigger pulse generation system capable of delivering a multiplicity of isolated 100 kV trigger pulses with picosecond simultaneity. 2 figs.

Aaland, K.

1980-02-19T23:59:59.000Z

53

Optical time of flight studies of lithium plasma in double pulse laser ablation: Evidence of inverse Bremsstrahlung absorption  

SciTech Connect

The early stage of formation of lithium plasma in a collineardouble pulse laser ablation mode has been studied using optical time of flight (OTOF) spectroscopy as a function of inter-pulse delay time, the distance from the target surface and the fluence of the ablation lasers. The experimental TOF measurements were carried out for lithium neutral (670.8?nm and 610.3?nm), and ionic (548.4?nm and 478.8?nm) lines. These experimental observations have been compared with that for single pulse laser ablation mode. It is found that depending on the fluence and laser pulse shape of the first pre-ablation laser and the second main ablation laser, the plasma plume formation and its characteristic features can be described in terms of plume-plume or laser-plume interaction processes. Moreover, the enhancement in the intensity of Li neutral and ionic lines is observed when the laser-plume interaction is the dominant process. Here, we see the evidence of the role of inverse Bremsstrahlung absorption process in the initial stage of formation of lithium plasma in this case.

Sivakumaran, V.; Joshi, H. C.; Singh, R. K.; Kumar, Ajai, E-mail: ajai@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

2014-06-15T23:59:59.000Z

54

Preliminary Design of a Pulsed Detonation Based Combined Cycle Engine Ramakanth Munipalli*  

E-Print Network (OSTI)

1 Preliminary Design of a Pulsed Detonation Based Combined Cycle Engine Ramakanth Munipalli combined cycle engine using periodic detonation waves are presented here. Four modes of operation are used detonation rocket for take off to moderate supersonic Mach numbers (2) A pulsed normal detonation wave mode

Texas at Arlington, University of

55

Direct coupling of pulsed radio frequency and pulsed high power in novel pulsed power system for plasma immersion ion implantation  

SciTech Connect

A novel power supply system that directly couples pulsed high voltage (HV) pulses and pulsed 13.56 MHz radio frequency (rf) has been developed for plasma processes. In this system, the sample holder is connected to both the rf generator and HV modulator. The coupling circuit in the hybrid system is composed of individual matching units, low pass filters, and voltage clamping units. This ensures the safe operation of the rf system even when the HV is on. The PSPICE software is utilized to optimize the design of circuits. The system can be operated in two modes. The pulsed rf discharge may serve as either the seed plasma source for glow discharge or high-density plasma source for plasma immersion ion implantation (PIII). The pulsed high-voltage glow discharge is induced when a rf pulse with a short duration or a larger time interval between the rf and HV pulses is used. Conventional PIII can also be achieved. Experiments conducted on the new system confirm steady and safe operation.

Gong Chunzhi; Tian Xiubo; Yang Shiqin [State Key Laboratory of Advanced Welding Production and Technology, School of Materials Science and Engineering, Harbin Institute of Technology, 150001 Harbin (China); Fu, Ricky K. Y.; Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

2008-04-15T23:59:59.000Z

56

Modes of Operation Encryption with Block Ciphers: Modes of Operation  

E-Print Network (OSTI)

(ECB) · Cipher Block Chaining mode (CBC) · Output Feedback mode (OFB) · Cipher Feedback mode (CFB) · Cipher Feedback mode (CFB) · Counter mode (CTR) · Galois Counter Mode (GCM) · All of the 6 modes have one

57

Optically pulsed electron accelerator  

DOE Patents (OSTI)

An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

Fraser, J.S.; Sheffield, R.L.

1985-05-20T23:59:59.000Z

58

Optically pulsed electron accelerator  

DOE Patents (OSTI)

An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

Fraser, John S. (Los Alamos, NM); Sheffield, Richard L. (Los Alamos, NM)

1987-01-01T23:59:59.000Z

59

Designation of Mode Mix in Orthotropic Composite Delamination Problems  

Science Journals Connector (OSTI)

In interfacial fracture modeling of composite delamination, mode mix is typically specified in terms of energy release rates. Other near-tip quantities can be used to designate mode mix, however. This paper consi...

S.H. Narayan; J.L. Beuth

60

Method and means of transmitting and receiving broad-band unipolar, ultrasonic pulses for ultrasonic inspection  

DOE Patents (OSTI)

The invention includes a means and method for transmitting and receiving broadband, unipolar, ultrasonic pulses for ultrasonic inspection. The method comprises generating a generally unipolar ultrasonic stress pulse from a low impedance voltage pulse transmitter along a low impedance electrical pathway to an ultrasonic transducer, and receiving the reflected echo of the pulse by the transducer, converting it to a voltage signal, and passing it through a high impedance electrical pathway to an output. The means utilizes electrical components according to the method. The means and method allow a single transducer to be used in a pulse/echo mode, and facilitates alternatingly transmitting and receiving the broadband, unipolar, ultrasonic pulses. 25 figures.

Thompson, D.O.; Hsu, D.K.

1993-12-14T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Pulsed dc self-sustained magnetron sputtering  

SciTech Connect

The magnetron sputtering has become one of the commonly used techniques for industrial deposition of thin films and coatings due to its simplicity and reliability. At standard magnetron sputtering conditions (argon pressure of {approx}0.5 Pa) inert gas particles (necessary to sustain discharge) are often entrapped in the deposited films. Inert gas contamination can be eliminated during the self-sustained magnetron sputtering (SSS) process, where the presence of the inert gas is not a necessary requirement. Moreover the SSS process that is possible due to the high degree of ionization of the sputtered material also gives a unique condition during the transport of sputtered particles to the substrate. So far it has been shown that the self-sustained mode of magnetron operation can be obtained using dc powering (dc-SSS) only. The main disadvantage of the dc-SSS process is its instability related to random arc formation. In such case the discharge has to be temporarily extinguished to prevent damaging both the magnetron source and power supply. The authors postulate that pulsed powering could protect the SSS process against arcs, similarly to reactive pulsed magnetron deposition processes of insulating thin films. To put this concept into practice, (i) the high enough plasma density has to be achieved and (ii) the type of pulsed powering has to be chosen taking plasma dynamics into account. In this article results of pulsed dc self-sustained magnetron sputtering (pulsed dc-SSS) are presented. The planar magnetron equipped with a 50 mm diameter and 6 mm thick copper target was used during the experiments. The maximum target power was about 11 kW, which corresponded to the target power density of {approx}560 W/cm{sup 2}. The magnetron operation was investigated as a function of pulse frequency (20-100 kHz) and pulse duty factor (50%-90%). The discharge (argon) extinction pressure level was determined for these conditions. The plasma emission spectra (400-410 nm range) and deposition rates were observed for both dc and pulsed dc self-sustained sputtering processes. The pulse characteristics of the voltage and current of the magnetron source during pulsed dc-SSS operation are shown. The presented results illustrate that a stable pulsed dc-SSS process can be obtained at a pulsing frequency in the range of 60-90 kHz and duty factor of 80%-90%.

Wiatrowski, A.; Posadowski, W. M.; Radzimski, Z. J. [Faculty of Microsystems, Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, 50-372 Wroclaw (Poland); Silicon Quest International, Santa Clara, California (United States)

2008-09-15T23:59:59.000Z

62

High voltage pulse conditioning  

DOE Patents (OSTI)

Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.

Springfield, Ray M. (Sante Fe, NM); Wheat, Jr., Robert M. (Los Alamos, NM)

1990-01-01T23:59:59.000Z

63

Plasma parameters of pulsed-dc discharges in methane used to deposit diamondlike carbon films  

SciTech Connect

Here we approximate the plasma kinetics responsible for diamondlike carbon (DLC) depositions that result from pulsed-dc discharges. The DLC films were deposited at room temperature by plasma-enhanced chemical vapor deposition (PECVD) in a methane (CH{sub 4}) atmosphere at 10 Pa. We compared the plasma characteristics of asymmetric bipolar pulsed-dc discharges at 100 kHz to those produced by a radio frequency (rf) source. The electrical discharges were monitored by a computer-controlled Langmuir probe operating in time-resolved mode. The acquisition system provided the intensity-voltage (I-V) characteristics with a time resolution of 1 mus. This facilitated the discussion of the variation in plasma parameters within a pulse cycle as a function of the pulse waveform and the peak voltage. The electron distribution was clearly divided into high- and low-energy Maxwellian populations of electrons (a bi-Maxwellian population) at the beginning of the negative voltage region of the pulse. We ascribe this to intense stochastic heating due to the rapid advancing of the sheath edge. The hot population had an electron temperature T{sub e}{sup hot} of over 10 eV and an initial low density n{sub e}{sup hot} which decreased to zero. Cold electrons of temperature T{sub e}{sup cold}approx1 eV represented the majority of each discharge. The density of cold electrons n{sub e}{sup cold} showed a monotonic increase over time within the negative pulse, peaking at almost 7x10{sup 10} cm{sup -3}, corresponding to the cooling of the hot electrons. The plasma potential V{sub p} of approx30 V underwent a smooth increase during the pulse and fell at the end of the negative region. Different rates of CH{sub 4} conversion were calculated from the DLC deposition rate. These were explained in terms of the specific activation energy E{sub a} and the conversion factor x{sub dep} associated with the plasma processes. The work deepens our understanding of the advantages of using pulsed power supplies for the PECVD of hard metallic and protective coatings for industrial applications (optics, biomedicine, and electronics).

Corbella, C.; Rubio-Roy, M.; Bertran, E.; Andujar, J. L. [FEMAN Group, IN2UB, Departament de Fisica Aplicada i Optica, Universitat de Barcelona, c/Marti i Franques 1, E-08028 Barcelona (Spain)

2009-08-01T23:59:59.000Z

64

Accelerated guided atomic pulse  

Science Journals Connector (OSTI)

The deleterious effects of dispersion on a propagating coherent atomic pulse, along the axis of a traveling-wave laser beam, can be ameliorated by the nonlinear self-interacting force due to dipole-dipole coupling between atoms. We show that a wide atomic pulse with a particular profile can retain its shape during propagation and, moreover, the momentum of the pulse increases due to photon absorption. For the wide soliton case, we demonstrate analytically that the self-interacting atomic force scales inversely with the third power of the pulse width.

S. Dyrting; Weiping Zhang; B. C. Sanders

1997-09-01T23:59:59.000Z

65

Photonic generation of UWB pulses with pulse position modulation  

E-Print Network (OSTI)

Photonic generation of UWB pulses with pulse position modulation H. Mu and J. Yao A novel photonic approach to generating ultra-wideband (UWB) signals with pulse position modulation (PPM) is proposed delay-line filter for UWB monocycle pulse generation, the second subsystem being a pulse

Yao, Jianping

66

Kink modes in pedestal  

SciTech Connect

Kink modes are investigated in pedestal for shaped tokamaks. An analytic combining criterion is presented. It lies on the middle of the sufficient criterion of Lortz and necessary criterion of Mercier giving a more restricted necessary criterion. Growth rates and mode structure are calculated. For large poloidal mode number, the modes are highly localized in both poloidal and radial directions. The modes increase rapidly when they approach to the resonant surface. They are typical of edge localized modes (ELMs). It is assumed that the modes vanish inside the next resonant surface, then, there seems to be a second stable region. Several mitigation methods for controlling ELMs are proposed.

Wang, Z. T. [Southwestern Institute of Physics, Chengdu 610041 (China) [Southwestern Institute of Physics, Chengdu 610041 (China); College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China); He, Z. X.; Dong, J. Q.; Wang, Z. H.; Xu, M. [Southwestern Institute of Physics, Chengdu 610041 (China)] [Southwestern Institute of Physics, Chengdu 610041 (China); Xu, X. L.; Mou, M. L.; Sun, T. T.; Huang, J.; Chen, S. Y.; Tang, C. J. [College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China)] [College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China)

2014-03-15T23:59:59.000Z

67

MHK Technologies/Pulse Stream 100 | Open Energy Information  

Open Energy Info (EERE)

Pulse Stream 100 Pulse Stream 100 < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Pulse Stream 100.jpg Technology Profile Primary Organization Pulse Tidal Ltd Project(s) where this technology is utilized *MHK Projects/Pulse Stream 100 Demonstration Project Technology Resource Click here Wave Technology Type Click here Oscillating Wave Surge Converter Technology Readiness Level Click here TRL 5/6: System Integration and Technology Laboratory Demonstration Technology Description The 100kW Humber prototype system uses tidal streams to oscillate horizontal blades rather than extracting energy in the same way as a wind turbine through rotary blades. This mode of operation is the key to the device's unique access to shallow water and has so far shown that it can harness enough energy to power 70 homes. The device is connected to the national grid through nearby industrial process plant Millennium Inorganic Chemicals and Ethernet connected through neighbouring resin manufacturing company Cray Valley.

68

Chaotic Pulse Trains  

E-Print Network (OSTI)

We study a third-order nonlinear ordinary differential equation whose solutions, under certain specific conditions, are individual pulses. These correspond to homoclinic orbits in the phase space of the equation and we study the possible pulse types in some detail. Sufficiently close to the conditions under which a homoclinic orbit exists, the solutions take the form of trains of well-separated pulses. A measure of closeness to homoclinic conditions provides a small parameter for the development of an asymptotic solution consisting of superposed, isolated pulses. The solvability condition in the resulting singular perturbation theory is a {\\its timing map} relating successive pulse spacings. This map of the real line onto itself, together with the known form of the homoclinic orbit, provides a concise and accurate solution of the equation.

N. J. Balmforth; G. R. Ierley; E. A. Spiegel

1993-09-08T23:59:59.000Z

69

Are "EIT Waves" Fast-Mode MHD Waves?  

E-Print Network (OSTI)

We examine the nature of large-scale, coronal, propagating wave fronts (``EIT waves'') and find they are incongruous with solutions using fast-mode MHD plane-wave theory. Specifically, we consider the following properties: non-dispersive single pulse manifestions, observed velocities below the local Alfven speed, and different pulses which travel at any number of constant velocities, rather than at the ``predicted'' fast-mode speed. We discuss the possibility of a soliton-like explanation for these phenomena, and show how it is consistent with the above-mentioned aspects.

M. J. Wills-Davey; C. E. DeForest; J. O. Stenflo

2007-04-23T23:59:59.000Z

70

Pulsed High Duty-Cycle Operation of ? ~ 8m Quantum Cascade Lasers  

Science Journals Connector (OSTI)

We report on high duty-cycle pulsed and burst-mode operation of ?~8m quantum cascade lasers under ambient conditions for photo-acoustic spectroscopy. An optimum in average optical...

Ko, Tiffany; Liu, Zhijun; Gmachl, Claire

71

Loan Terms  

Energy.gov (U.S. Department of Energy (DOE))

The following terms are important to understand and use confidently as you discuss, negotiate, and finalize details of the clean energy loan product with the selected financial institution partners. You will need to negotiate loan origination procedures, interest rates, loan tenors, underwriting guidelines, and other terms outlined below.

72

Pulse measurement apparatus and method  

DOE Patents (OSTI)

An embodiment of the invention is directed to a pulse measuring system that measures a characteristic of an input pulse under test, particularly the pulse shape of a single-shot, nano-second duration, high shape-contrast optical or electrical pulse. An exemplary system includes a multi-stage, passive pulse replicator, wherein each successive stage introduces a fixed time delay to the input pulse under test, a repetitively-gated electronic sampling apparatus that acquires the pulse train including an entire waveform of each replica pulse, a processor that temporally aligns the replicated pulses, and an averager that temporally averages the replicated pulses to generate the pulse shape of the pulse under test. An embodiment of the invention is directed to a method for measuring an optical or an electrical pulse shape. The method includes the steps of passively replicating the pulse under test with a known time delay, temporally stacking the pulses, and temporally averaging the stacked pulses. An embodiment of the invention is directed to a method for increasing the dynamic range of a pulse measurement by a repetitively-gated electronic sampling device having a rated dynamic range capability, beyond the rated dynamic range of the sampling device; e.g., enhancing the dynamic range of an oscilloscope. The embodied technique can improve the SNR from about 300:1 to 1000:1. A dynamic range enhancement of four to seven bits may be achieved.

Marciante, John R. (Webster, NY); Donaldson, William R. (Pittsford, NY); Roides, Richard G. (Scottsville, NY)

2011-10-25T23:59:59.000Z

73

Sub-100 fs pulses at watt-level powers from a dissipative-soliton fiber laser  

E-Print Network (OSTI)

with cladding pumping for high average power. The laser generates 31 nJ chirped pulses at 70 MHz repetition rate of double-clad (DC) gain fiber is common, and there are a few reports of mode-locked lasers that employ DCSub-100 fs pulses at watt-level powers from a dissipative-soliton fiber laser K. Kieu,* W. H

Kieu, Khanh

74

Increasing the Magnetic Helicity Content of a Plasma by Pulsing a Magnetized Source  

Science Journals Connector (OSTI)

By operating a magnetized coaxial gun in a pulsed mode it is possible to produce large voltage pulses of duration ?500????s while reaching a few kV, giving a discrete input of helicity into a spheromak. In the sustained spheromak physics experiment (SSPX), it is observed that pulsing serves to nearly double the stored magnetic energy and double the temperature. We discuss these results by comparison with 3D MHD simulations of the same phenomenon.

S. Woodruff; B. W. Stallard; H. S. McLean; E. B. Hooper; R. Bulmer; B. I. Cohen; D. N. Hill; C. T. Holcomb; J. Moller; R. D. Wood

2004-11-12T23:59:59.000Z

75

Yb-doped Large Pitch Fiber with 105m Mode Field Diameter  

Science Journals Connector (OSTI)

We present an active Yb-doped Large Pitch Fiber with 105m mode field diameter. It was tested in a fiber CPA system delivering <500fs, 2mJ pulses with 3.8GW peak power. The...

Jansen, Florian; Stutzki, Fabian; Eidam, Tino; Rothhardt, Jan; Hdrich, Steffen; Carstens, Henning; Jauregui, Cesar; Limpert, Jens; Tnnermann, Andreas

76

Beat note stabilization of mode-locked lasers for quantum information processing  

Science Journals Connector (OSTI)

We stabilize a chosen radio frequency beat note between two optical fields derived from the same mode-locked laser pulse train in order to coherently manipulate quantum information....

Islam, R; Campbell, W C; Choi, T; Clark, S M; Conover, C W S; Debnath, S; Edwards, E E; Fields, B; Hayes, D; Hucul, D; Inlek, I V; Johnson, K G; Korenblit, S; Lee, A; Lee, K W; Manning, T A; Matsukevich, D N; Mizrahi, J; Quraishi, Q; Senko, C; Smith, J; Monroe, C

2014-01-01T23:59:59.000Z

77

Pulse-burst  

NLE Websites -- All DOE Office Websites (Extended Search)

Pulse-burst laser systems for fast Thomson scattering "invited... a... D. J. Den Hartog, 1,2,b J. R. Ambuel, 3 M. T. Borchardt, 1 A. F. Falkowski, 1 W. S. Harris, 1 D. J. Holly,...

78

Pulsed Neutron Powder Diffraction  

Science Journals Connector (OSTI)

The nature and scope of powder diffraction with a white, pulsed beam of neutrons is discussed. Analysis of the data by the Rietveld profile technique is described in brief, and a range of applications in solid...

A. K. Cheetham

1988-01-01T23:59:59.000Z

79

Pulse charging device  

SciTech Connect

This paper describes a device for pulse charging of capacitor storage devices of high-power nanosecond generators. The charging voltage reaches 30 kV, the charged capacitance is 2-100 nF, the charging time is 5-10 usec, the pulse frequency reaches 10 kHz, and the average power of the device is 15 kW. The device uses two-section oscillatory charging of the capacitors from a dc supply through high-speed thyristors and a pulse transformer. The described device is intended for use as part of a test bench for high-power nanosecond pulse generators for pumping gas lasers and their components.

Butakov, L.D.; Dubich, V.K.; Lashuk, N.A.; Shubkin, N.G.; Vizir', V.A.

1986-03-01T23:59:59.000Z

80

Drop shaping by laser-pulse impact  

E-Print Network (OSTI)

We study the hydrodynamic response of a falling drop hit by a laser pulse. Combining high-speed with stroboscopic imaging we report that a millimeter-sized dyed water drop hit by a milli-Joule nanosecond laser-pulse deforms and propels forward at several meters per second, until it eventually fragments. We show that the drop motion results from the recoil momentum imparted at the drop surface by water vaporization. We measure the propulsion speed and the time-deformation law of the drop, complemented by boundary integral simulations. We explain the drop propulsion and shaping in terms of the laser pulse energy and drop surface tension. These findings are crucial for the generation of extreme ultraviolet (EUV) light in lithography machines.

Klein, Alexander L; Visser, Claas Willem; Lhuissier, Henri; Sun, Chao; Snoeijer, Jacco H; Villermaux, Emmanuel; Lohse, Detlef; Gelderblom, Hanneke

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Pulse magnetic welder  

DOE Patents (OSTI)

A welder is described for automated closure of fuel pins by a pulsed magnetic process in which the open end of a length of cladding is positioned within a complementary tube surrounded by a pulsed magnetic welder. Seals are provided at each end of the tube, which can be evacuated or can receive tag gas for direct introduction to the cladding interior. Loading of magnetic rings and end caps is accomplished automatically in conjunction with the welding steps carried out within the tube.

Christiansen, D.W.; Brown, W.F.

1984-01-01T23:59:59.000Z

82

Singular Modes of the Electromagnetic Field  

E-Print Network (OSTI)

We show that the mode corresponding to the point of essential spectrum of the electromagnetic scattering operator is a vector-valued distribution representing the square root of the three-dimensional Dirac's delta function. An explicit expression for this singular mode in terms of the Weyl sequence is provided and analyzed. An essential resonance thus leads to a perfect localization (confinement) of the electromagnetic field, which in practice, however, may result in complete absorption.

Neil V. Budko; Alexander B. Samokhin

2006-06-15T23:59:59.000Z

83

Singular Modes of the Electromagnetic Field  

E-Print Network (OSTI)

We show that the mode corresponding to the point of essential spectrum of the electromagnetic scattering operator is a vector-valued distribution representing the square root of the three-dimensional Dirac's delta function. An explicit expression for this singular mode in terms of the Weyl sequence is provided and analyzed. An essential resonance thus leads to a perfect localization (confinement) of the electromagnetic field, which in practice, however, may result in complete absorption.

Budko, N V; Budko, Neil V.; Samokhin, Alexander B.

2006-01-01T23:59:59.000Z

84

Pulse shaping with transmission lines  

DOE Patents (OSTI)

A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

Wilcox, Russell B. (Oakland, CA)

1987-01-01T23:59:59.000Z

85

Photoconductive circuit element pulse generator  

DOE Patents (OSTI)

A pulse generator for characterizing semiconductor devices at millimeter wavelength frequencies where a photoconductive circuit element (PCE) is biased by a direct current voltage source and produces short electrical pulses when excited into conductance by short laser light pulses. The electrical pulses are electronically conditioned to improve the frequency related amplitude characteristics of the pulses which thereafter propagate along a transmission line to a device under test.

Rauscher, Christen (Alexandria, VA)

1989-01-01T23:59:59.000Z

86

HydroPulse Drilling  

SciTech Connect

Tempress HydroPulse{trademark} tool increases overbalanced drilling rates by generating intense suction pulses at the drill bit. This report describes the operation of the tool; results of pressure drilling tests, wear tests and downhole drilling tests; and the business case for field applications. The HydroPulse{trademark} tool is designed to operate on weighted drilling mud at conventional flow rates and pressures. Pressure drilling tests confirm that the HydroPulse{trademark} tool provides 33% to 200% increased rate of penetration. Field tests demonstrated conventional rotary and mud motor drilling operations. The tool has been operated continuous for 50 hours on weighted mud in a wear test stand. This level of reliability is the threshold for commercial application. A seismic-while-drilling version of the tool was also developed and tested. This tool was used to demonstrate reverse vertical seismic profiling while drilling an inclined test well with a PDC bit. The primary applications for the HydroPulse{trademark} tool are deep onshore and offshore drilling where rate of penetration drives costs. The application of the seismic tool is vertical seismic profiling-while-drilling and look-ahead seismic imaging while drilling.

J.J. Kolle

2004-04-01T23:59:59.000Z

87

To Expected Charge Fluctuations Data from the long pulse run 17-Feb-2002  

E-Print Network (OSTI)

Te if possible - button BPMs equipped with electronics from the undulator - additional stripline BPM BIS long pulse operation mode in analysis mode reentrant BPM Protvino BPM dogleg +vertical steerers stripline BPM button BPMs button BPM beamdump 25 MeV beam, 8mA@10 Hz #12;Resolution of the Injector

88

Laser pulse sampler  

DOE Patents (OSTI)

The Laser Pulse Sampler (LPS) measures temporal pulse shape without the problems of a streak camera. Unlike the streak camera, the laser pulse directly illuminates a camera in the LPS, i.e., no additional equipment or energy conversions are required. The LPS has several advantages over streak cameras. The dynamic range of the LPS is limited only by the range of its camera, which for a cooled camera can be as high as 16 bits, i.e., 65,536. The LPS costs less because there are fewer components, and those components can be mass produced. The LPS is easier to calibrate and maintain because there is only one energy conversion, i.e., photons to electrons, in the camera. 5 figs.

Vann, C.

1998-03-24T23:59:59.000Z

89

Laser pulse sampler  

DOE Patents (OSTI)

The Laser Pulse Sampler (LPS) measures temporal pulse shape without the problems of a streak camera. Unlike the streak camera, the laser pulse directly illuminates a camera in the LPS, i.e., no additional equipment or energy conversions are required. The LPS has several advantages over streak cameras. The dynamic range of the LPS is limited only by the range of its camera, which for a cooled camera can be as high as 16 bits, i.e., 65,536. The LPS costs less because there are fewer components, and those components can be mass produced. The LPS is easier to calibrate and maintain because there is only one energy conversion, i.e., photons to electrons, in the camera.

Vann, Charles (Fremont, CA)

1998-01-01T23:59:59.000Z

90

Pulse power linac  

DOE Patents (OSTI)

A linear acceleration for charged particles is constructed of a plurality of transmission line sections that extend between a power injection region and an accelerating region. Each line section is constructed of spaced plate-like conductors and is coupled to an accelerating gap located at the accelerating region. Each gap is formed between a pair of apertured electrodes, with all of the electrode apertures being aligned along a particle accelerating path. The accelerating gaps are arranged in series, and at the injection region the line sections are connected in parallel. At the injection region a power pulse is applied simultaneously to all line sections. The line sections are graduated in length so that the pulse reaches the gaps in a coordinated sequence whereby pulse energy is applied to particles as they reach each of the gaps along the accelerating path.

Villa, Francesco (Alameda, CA)

1990-01-01T23:59:59.000Z

91

SNMR pulse sequence phase cycling  

DOE Patents (OSTI)

Technologies applicable to SNMR pulse sequence phase cycling are disclosed, including SNMR acquisition apparatus and methods, SNMR processing apparatus and methods, and combinations thereof. SNMR acquisition may include transmitting two or more SNMR pulse sequences and applying a phase shift to a pulse in at least one of the pulse sequences, according to any of a variety cycling techniques. SNMR processing may include combining SNMR from a plurality of pulse sequences comprising pulses of different phases, so that desired signals are preserved and indesired signals are canceled.

Walsh, David O; Grunewald, Elliot D

2013-11-12T23:59:59.000Z

92

Passively harmonic mode locked erbium doped fiber soliton laser with carbon nanotubes based  

E-Print Network (OSTI)

Passively harmonic mode locked erbium doped fiber soliton laser with carbon nanotubes based. Tokumoto, H. Kataura, and Y. Achiba, "Sub-200-fs pulsed erbium- doped fiber laser using a carbon nanotube fs erbium-doped fiber laser mode locked with a cellulose polymer film containing single-wall carbon

Turitsyn, Sergei K.

93

Coupled-Oscillator Arrays for Millimeter-Wave Power-Combining and Mode-Locking  

E-Print Network (OSTI)

. 1. INTRODUCTION Obtaining useful levels of power from solid-state millimeter- wave systems trains of high-energy pulses. This new operation is based on a mode- locking technique similarIF1 P-1 Coupled-Oscillator Arrays for Millimeter-Wave Power-Combining and Mode-Locking Robert A

York, Robert A.

94

Spectral characteristics of ultra-short laser pulses in plasma amplifiers  

SciTech Connect

Amplification of laser pulses based on the backscattering process in plasmas can be performed using either the response of an electron plasma wave or an ion-acoustic wave. However, if the pulse durations become very short and the natural spread in frequency a substantial amount of the frequency itself, the Raman and Brillouin processes start to mix. Kinetic simulations show the transition from a pure amplification regime, in this case strong-coupling Brillouin, to a regime where a considerable downshift of the frequency of the amplified pulse takes place. It is conjectured that in the case of very short pulses, multi-modes are excited which contribute to the amplification process.

Riconda, C. [LULI, Universit Pierre et Marie CurieEcole PolytechniqueCNRSCEA, 75252 Paris (France)] [LULI, Universit Pierre et Marie CurieEcole PolytechniqueCNRSCEA, 75252 Paris (France); Weber, S. [IZEST, Ecole PolytechniqueCEA, 91128 Palaiseau (France) [IZEST, Ecole PolytechniqueCEA, 91128 Palaiseau (France); Institute of Physics of the ASCR, ELI-Beamlines, 18221 Prague (Czech Republic); Lancia, L. [SAPIENZA, University of Rome, Dip. SBAI, 00161 Rome (Italy) [SAPIENZA, University of Rome, Dip. SBAI, 00161 Rome (Italy); INFNSez. RomaSAPIENZA, University of Rome, 00185 Rome (Italy); Marqus, J.-R.; Fuchs, J. [LULI, CNRSEcole PolytechniqueUniversit Pierre et Marie CurieCEA, 91128 Palaiseau (France)] [LULI, CNRSEcole PolytechniqueUniversit Pierre et Marie CurieCEA, 91128 Palaiseau (France); Mourou, G. A. [IZEST, Ecole PolytechniqueCEA, 91128 Palaiseau (France)] [IZEST, Ecole PolytechniqueCEA, 91128 Palaiseau (France)

2013-08-15T23:59:59.000Z

95

Downhole pulse tube refrigerators  

SciTech Connect

This report summarizes a preliminary design study to explore the plausibility of using pulse tube refrigeration to cool instruments in a hot down-hole environment. The original motivation was to maintain Dave Reagor`s high-temperature superconducting electronics at 75 K, but the study has evolved to include three target design criteria: cooling at 30 C in a 300 C environment, cooling at 75 K in a 50 C environment, cooling at both 75 K and 30 C in a 250 C environment. These specific temperatures were chosen arbitrarily, as representative of what is possible. The primary goals are low cost, reliability, and small package diameter. Pulse-tube refrigeration is a rapidly growing sub-field of cryogenic refrigeration. The pulse tube refrigerator has recently become the simplest, cheapest, most rugged and reliable low-power cryocooler. The authors expect this technology will be applicable downhole because of the ratio of hot to cold temperatures (in absolute units, such as Kelvin) of interest in deep drilling is comparable to the ratios routinely achieved with cryogenic pulse-tube refrigerators.

Swift, G.; Gardner, D. [Los Alamos National Lab., NM (United States). Condensed Matter and Thermal Physics Group

1997-12-01T23:59:59.000Z

96

Mode Initialization for On-line Estimation of Power System Electromechanical Modes  

SciTech Connect

Measurement-based mode estimation methods are utilized to estimate electromechanical modes of a power system using phasor measurement units (PMU) data. These methods need to extract a certain amount of information before they can give useable mode estimation. Traditionally, the information is gathered solely from measurement data. Priori mode information from other resources (e.g. model eigenvalue analysis, engineering knowledge) are not fully utilized. For real time application, this means that mode estimation takes time to converge. By adding a mode regularization term in the objective function, this paper proposes a mode initialization method to include priori mode information in a regularized robust recursive least squares (R3LS) algorithm for on-line mode estimation. The proposed method is tested using a simple model, a 17 machine model and is shown to be able to shorten the convergence period of the R3LS algorithm. The proposed method is also applied on the measurement data recorded right before a major power outage in the western North American Grid on August 10th 1996 to show its potential applica-tion in detecting an approaching small signal stability problem.

Zhou, Ning; Trudnowski, Daniel; Pierre, John W.

2009-03-18T23:59:59.000Z

97

Architecture AddressingModes  

E-Print Network (OSTI)

MIPS R2000 Architecture and Assembly (Part 1) 1. CPU Registers 2. Byte Order 3. AddressingModes 4­endian byte order 3 2 1 0 0 1 2 3 Or Byte number #12; AddressingModes . MIPS is a load/store architecture . RICS -- Load/Store architecture -- All instructions have equal length of 4 bytes -- Every register can

Nguyen, Dat H.

98

Micropulse slippage and optical mode distortion in the Boeing APLE amplifier  

Science Journals Connector (OSTI)

In the Boeing Average Power Laser Experiment (APLE), the free electron laser (FEL) oscillator produces short optical pulses for input to the amplifier section. Micropulse slippage can become significant in the amplifier, competing with the effects of high gain and optical mode distortion. A two-dimensional simulation is used to study pulse slippage, and a three-dimensional simulation is used to study mode distortion. A four-dimensional simulation is used to simultaneously study these effects, and to look at the sensitivity of the efficiency to changes in various FEL parameters. We find that high gain and mode distortion effects dominate the pulse slippage effects. The amplifier is fairly insensitice to beam quality degradation and changes in the initial optical field, but a significant improvement in efficiency could be achieved by shortening the electron pulse.

J. Blau; D.J. Frost; W.B. Colson

1993-01-01T23:59:59.000Z

99

Multi-Pulse SCR Rectifiers.  

E-Print Network (OSTI)

??This thesis presents the introduction, analysis and experimental verification of the six-pulse SCR rectifier and multi-pulse SCR rectifiers. As a fundamental three-phase controllable ac-dc converter, (more)

Li, Mei

2005-01-01T23:59:59.000Z

100

Sequentially pulsed traveling wave accelerator  

DOE Patents (OSTI)

A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

Caporaso, George J. (Livermore, CA); Nelson, Scott D. (Patterson, CA); Poole, Brian R. (Tracy, CA)

2009-08-18T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Superluminal transmission of light pulses through optically opaque barriers  

Science Journals Connector (OSTI)

Using simple considerations of causal electrodynamics we analyze the occurrence of superluminal transmission of light pulses through optically opaque barriers. We find that the phenomenon appears whenever the main frequency components of the pulse are confined to frequency regions where the presence of the barrier decreases the density of states of the electromagnetic modes of the system. We also show that these frequency regions correspond to the transmission gaps of sufficiently wide barriers. We discuss a simple theory for the density of states of the barrier system and compare the results of such a theory with exact numerical calculations.

V. Romero-Rochn; R. P. Duarte-Zamorano; S. Nilsen-Hofseth; R. G. Barrera

2001-01-23T23:59:59.000Z

102

High energy mode locked fiber oscillators for high contrast, high energy petawatt laser seed sources  

SciTech Connect

In a high-energy petawatt laser beam line the ASE pulse contrast is directly related to the total laser gain. Thus a more energetic input pulse will result in increased pulse contrast at the target. We have developed a mode-locked fiber laser with high quality pulses and energies exceeding 25nJ. We believe this 25nJ result is scalable to higher energies. This oscillator has no intra-cavity dispersion compensation, which yields an extremely simple, and elegant laser configuration. We will discuss the design of this laser, our most recent results and characterization of all the key parameters relevant to it use as a seed laser. Our oscillator is a ring cavity mode-locked fiber laser [1]. These lasers operate in a self-similar pulse propagation regime characterized by a spectrum that is almost square. This mode was found theoretically [2] to occur only in the positive dispersion regime. Further increasing positive dispersion should lead to increasing pulse energy [2]. We established that the positive dispersion required for high-energy operation was approximately that of 2m of fiber. To this end, we constructed a laser cavity similar to [1], but with no gratings and only 2m of fiber, which we cladding pumped in order to ensure sufficient pump power was available to achieve mode-locked operation. A schematic of the laser is shown in figure 1 below. This laser produced low noise 25nJ pulses with a broad self similar spectrum (figure 2) and pulses that could be de-chirped to <100fs (figure 3). Pulse contrast is important in peta-watt laser systems. A major contributor to pulse contrast is amplified spontaneous emission (ASE), which is proportional to the gain in the laser chain. As the oscillator strength is increased, the required gain to reach 1PW pulses is decreased, reducing ASE and improving pulse contrast. We believe these lasers can be scaled in a stable fashion to pulse energies as high as 100nJ and have in fact seen 60nJ briefly in our lab, which is work still in progress. At this level, even if the pulses are not perfect, post-oscillator pulse cleaning can be used to create a clean high energy pulse for injection into a peta-watt laser beam line.

Dawson, J W; Messerly, M J; An, J; Kim, D; Barty, C J

2006-06-15T23:59:59.000Z

103

Mode-locked terahertz quantum cascade laser by direct phase synchronization  

SciTech Connect

Mode-locking of a terahertz quantum cascade laser is achieved using multimode injection seeding. Contrary to standard methods that rely on gain modulation, here a fixed phase relationship is directly imprinted to the laser modes. In this work, we demonstrate the generation of 9 ps phase mode-locked pulses around 2.75 THz. A direct measurement of the emitted field phase shows that it results from the phase of the initial injection.

Maussang, K.; Maysonnave, J.; Jukam, N.; Freeman, J. R.; Cavali, P.; Dhillon, S. S.; Tignon, J. [Laboratoire Pierre Aigrain, Ecole Normale Suprieure, CNRS (UMR 8551), Universit P. et M. Curie, Universit D. Diderot, 75005 Paris (France); Khanna, S. P.; Linfield, E. H.; Davies, A. G. [School of Electronic and Electrical Engineering, University of Leeds, Leeds LS9 2JT (United Kingdom); Beere, H. E.; Ritchie, D. A. [University of Cambridge, Cavendish Lab, Cambridge CB3 0HE (United Kingdom)

2013-12-04T23:59:59.000Z

104

Numerical investigation of pulse-modulated atmospheric radio frequency discharges in helium under different duty cycles  

SciTech Connect

Experiments observed that the pulse duty cycle has effects on the plasma homogeneity in pulse-modulated radio frequency (rf) discharges. In this paper, pulse-modulated rf (13.56 MHz) helium discharges are theoretically investigated using a two dimensional fluid model. With the pulse period being fixed to 15 {mu}s, it is found that when the pulse-on duration is over 4 {mu}s, i.e., the duty cycle is larger than approximately 27%, the discharge transits from an inhomogeneous to a homogeneous mode in every specific part of each pulse cycle under currently-used simulation parameters. More quantitative analysis shows that the discharge becomes more homogeneous as the duty cycle is increased but does not reach complete homogeneity. Possible reasons for the homogeneity improvement are discussed.

Sun Jizhong; Ding Zhengfen; Li Xuechun; Wang Dezhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China); Wang Qi [Dalian Institute of Semiconductor Technology, School of Electronics Science and Technology, Dalian University of Technology, Dalian 116023 (China)

2011-12-15T23:59:59.000Z

105

Mixed-mode oscillations in chemical systems Valery Petrov  

E-Print Network (OSTI)

, leading to correspondingly more complete Devil's staircases. An ex- actly comparable scenario is shown. The relative extents of the mixed-mode and nonmixed- mode forms are summarized in terms of a Devil's staircase. The completeness of the staircase as a second parameter is varied is discussed. The mechanisms by which the system

Showalter, Kenneth

106

Instrument performance study on the short and long pulse options of the second Spallation Neutron Source target station  

SciTech Connect

The Spallation Neutron Source (SNS) facility at the Oak Ridge National Laboratory is designed with an upgrade option for a future low repetition rate, long wavelength second target station. This second target station is intended to complement the scientific capabilities of the 1.4 MW, 60 Hz high power first target station. Two upgrade possibilities have been considered, the short and the long pulse options. In the short pulse mode, proton extraction occurs after the pulse compression in the accumulator ring. The proton pulse structure is thus the same as that for the first target station with a pulse width of ?0.7 ?s. In the long pulse mode, protons are extracted as they are produced by the linac, with no compression in the accumulator ring. The time width of the uncompressed proton pulse is ?1 ms. This difference in proton pulse structure means that neutron pulses will also be different. Neutron scattering instruments thus have to be designed and optimized very differently for these two source options which will directly impact the overall scientific capabilities of the SNS facility. In order to assess the merits of the short and long pulse target stations, we investigated a representative suit of neutron scattering instruments and evaluated their performance under each option. Our results indicate that the short pulse option will offer significantly better performance for the instruments and is the preferred choice for the SNS facility.

Zhao, J. K.; Herwig, Kenneth W.; Robertson, J. L.; Gallmeier, Franz X.; Riemer, Bernard W. [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2013-10-15T23:59:59.000Z

107

Excimer emission from pulsed microhollow cathode discharges in xenon  

SciTech Connect

Direct current (dc) microhollow cathode discharge (MHCD) is an intense source for excimer radiation in vacuum ultraviolet at a wavelength of 172 nm in a high pressure xenon (Xe) gas. The concentration of precursors for the excimer formation, i.e., excited and ionized gas atoms, increases significantly by applying high voltage pulse onto the dc MHCD over the pulse duration range from 20 to 100 ns. The intensity of the excimer emission for the voltage pulse of 20 ns duration exceeds that of the emission intensity obtained from the same MHCD operated only in the dc mode, by one order of magnitude. In addition, the emission intensity increases by one order of magnitude over the pulse duration range from 20 to 100 ns. It can be assumed that the emission intensity of the MHCD source increases as long as the duration of the high voltage pulse is shorter than the electron relaxation time. For the high voltage pulse of 100 ns duration, the emission intensity has been found to be further enhanced by a factor of three when the gas pressure is increased from 200 to 800 mbar.

Lee, B.-J.; Nam, S. H. [Pohang Accelerator Laboratory, Pohang, Kyungbuk 790-784 (Korea, Republic of)] [Pohang Accelerator Laboratory, Pohang, Kyungbuk 790-784 (Korea, Republic of); Rahaman, H. [CSIRCEERI Pilani, Rajasthan 333031 (India)] [CSIRCEERI Pilani, Rajasthan 333031 (India); Iberler, M.; Jacoby, J. [Institute of Applied Physics, Goethe University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany)] [Institute of Applied Physics, Goethe University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Frank, K. [Physics Department 1, University of Erlangen Nuremberg, 91058 Erlangen (Germany)] [Physics Department 1, University of Erlangen Nuremberg, 91058 Erlangen (Germany)

2013-12-15T23:59:59.000Z

108

Petawatt pulsed-power accelerator  

DOE Patents (OSTI)

A petawatt pulsed-power accelerator can be driven by various types of electrical-pulse generators, including conventional Marx generators and linear-transformer drivers. The pulsed-power accelerator can be configured to drive an electrical load from one- or two-sides. Various types of loads can be driven; for example, the accelerator can be used to drive a high-current z-pinch load. When driven by slow-pulse generators (e.g., conventional Marx generators), the accelerator comprises an oil section comprising at least one pulse-generator level having a plurality of pulse generators; a water section comprising a pulse-forming circuit for each pulse generator and a level of monolithic triplate radial-transmission-line impedance transformers, that have variable impedance profiles, for each pulse-generator level; and a vacuum section comprising triplate magnetically insulated transmission lines that feed an electrical load. When driven by LTD generators or other fast-pulse generators, the need for the pulse-forming circuits in the water section can be eliminated.

Stygar, William A. (Albuquerque, NM); Cuneo, Michael E. (Albuquerque, NM); Headley, Daniel I. (Albuquerque, NM); Ives, Harry C. (Albuquerque, NM); Ives, legal representative; Berry Cottrell (Albuquerque, NM); Leeper, Ramon J. (Albuquerque, NM); Mazarakis, Michael G. (Albuquerque, NM); Olson, Craig L. (Albuquerque, NM); Porter, John L. (Sandia Park, NM); Wagoner; Tim C. (Albuquerque, NM)

2010-03-16T23:59:59.000Z

109

mode | OpenEI  

Open Energy Info (EERE)

mode mode Dataset Summary Description Supplemental Table 46 of EIA AEO 2011 Early Release Source EIA Date Released December 08th, 2010 (4 years ago) Date Updated Unknown Keywords AEO Annual Energy Outlook EIA Energy Information Administration Fuel mode TEF transportation Transportation Energy Futures Data text/csv icon Transportation_Sector_Energy_Use_by_Fuel_Type_Within_a_Mode.csv (csv, 144.3 KiB) Quality Metrics Level of Review Some Review Comment Temporal and Spatial Coverage Frequency Annually Time Period 2008-2035 License License Open Data Commons Public Domain Dedication and Licence (PDDL) Comment Rate this dataset Usefulness of the metadata Average vote Your vote Usefulness of the dataset Average vote Your vote Ease of access Average vote Your vote Overall rating Average vote Your vote

110

High-speed pulse-shape generator, pulse multiplexer  

DOE Patents (OSTI)

The invention combines arbitrary amplitude high-speed pulses for precision pulse shaping for the National Ignition Facility (NIF). The circuitry combines arbitrary height pulses which are generated by replicating scaled versions of a trigger pulse and summing them delayed in time on a pulse line. The combined electrical pulses are connected to an electro-optic modulator which modulates a laser beam. The circuit can also be adapted to combine multiple channels of high speed data into a single train of electrical pulses which generates the optical pulses for very high speed optical communication. The invention has application in laser pulse shaping for inertial confinement fusion, in optical data links for computers, telecommunications, and in laser pulse shaping for atomic excitation studies. The invention can be used to effect at least a 10.times. increase in all fiber communication lines. It allows a greatly increased data transfer rate between high-performance computers. The invention is inexpensive enough to bring high-speed video and data services to homes through a super modem.

Burkhart, Scott C. (Livermore, CA)

2002-01-01T23:59:59.000Z

111

Spectrally tailored supercontinuum generation from single-mode-fiber amplifiers  

SciTech Connect

Spectral filtering of an all-normal-dispersion Yb-doped fiber laser was demonstrated effective for broadband supercontinuum generation in the picosecond time region. The picosecond pump pulses were tailored in spectrum with 1 nm band-pass filter installed between two single-mode fiber amplifiers. By tuning the spectral filter around 1028?nm, four-wave mixing was initiated in a photonic crystal fiber spliced with single-mode fiber, as manifested by the simultaneous generation of Stokes wave at 1076?nm and anti-Stokes wave at 984?nm. Four-wave mixing took place in cascade with the influence of stimulated Raman scattering and eventually extended the output spectrum more than 900?nm of 10?dB bandwidth. This technique allows smooth octave supercontinuum generation by using simple single-mode fiber amplifiers rather than complicated multistage large-mode-area fiber amplifiers.

Hao, Qiang; Guo, Zhengru; Zhang, Qingshan [Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System (Ministry of Education), School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093 (China); Liu, Yang; Li, Wenxue [State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 Zhongshan North Road, Shanghai 200062 (China); Zeng, Heping, E-mail: hpzeng@phy.ecnu.edu.cn [Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System (Ministry of Education), School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093 (China); State Key Laboratory of Precision Spectroscopy, East China Normal University, 3663 Zhongshan North Road, Shanghai 200062 (China)

2014-05-19T23:59:59.000Z

112

Coiled transmission line pulse generators  

DOE Patents (OSTI)

Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

McDonald, Kenneth Fox (Columbia, MO)

2010-11-09T23:59:59.000Z

113

Long Pulse EBW Start-up Experiments in MAST  

E-Print Network (OSTI)

The non-solenoid start-up technique reported here relies on a double mode conversion for electron Bernstein wave (EBW) excitation. It consists of the mode conversion of the ordinary mode, entering the plasma from the low field side of the tokamak, into the extraordinary (X) mode at a mirror-polarizer located at the high field side. The X mode propagates back to the plasma, passes through electron cyclotron resonance and experiences a subsequent X to EBW mode conversion near the upper hybrid resonance. Finally the excited EBW mode is totally absorbed at the Doppler shifted electron cyclotron resonance. The absorption of EBW remains high even in cold rarefied plasmas. Furthermore, EBW can generate significant plasma current giving the prospect of a fully solenoid-free plasma start-up. First experiments using this scheme were carried out on MAST [V. Shevchenko et al, Nuclear Fusion 50, 022004 (2010)]. Plasma currents up to 33 kA have been achieved using 28 GHz 100kW 90ms RF pulses. Recently experimental results ...

Shevchenko, V F; Caughman, J B; Diem, S; Mailloux, J; Brien, M R O; Peng, M; Saveliev, A N; Takase, Y; Tanaka, H; Taylor, G

2015-01-01T23:59:59.000Z

114

Pulsed Zeeman spectroscopy  

E-Print Network (OSTI)

wheel was attached to the wavei( ngth indicator and was used to interrupt the light striking a small photodiode. The output voltage from the photodiode was used to provide calibration points on the recorder. Photomultiplier An Amperex 56UVP... Vertical: 2 mv/cm Horizontal: 5 microseconds/cm 23 Phc tographic Measurements ~A. Ald t p t 1 pbd. db spectra of ruby as in Fig. l. A photodiode with a risetime of four nanoseconds was used to position the magneti. c field pulse in order...

Cullen, Raymond Paul

2012-06-07T23:59:59.000Z

115

Green Light Pulse Oximeter  

DOE Patents (OSTI)

A reflectance pulse oximeter that determines oxygen saturation of hemoglobin using two sources of electromagnetic radiation in the green optical region, which provides the maximum reflectance pulsation spectrum. The use of green light allows placement of an oximetry probe at central body sites (e.g., wrist, thigh, abdomen, forehead, scalp, and back). Preferably, the two green light sources alternately emit light at 560 nm and 577 nm, respectively, which gives the biggest difference in hemoglobin extinction coefficients between deoxyhemoglobin, RHb, and oxyhemoglobin, HbO.sub.2.

Scharf, John Edward (Oldsmar, FL)

1998-11-03T23:59:59.000Z

116

Deriving a mode logic using failure modes and effects analysis  

Science Journals Connector (OSTI)

Modes are widely used to structure the behaviour of control systems. However, derivation and verification of a mode logic for complex systems is challenging due to a large number of modes and intricate mode transitions. In this paper, we propose an approach to deriving, formalising and verifying consistency of a mode logic for fault-tolerant control systems. We propose to use failure modes and effects analysis (FMEA) to systematically derive the fault tolerance part of the mode logic. We formalise the mode logic and define mode consistency properties for layered systems with reconfigurable components. We use our formalisation to develop and verify a mode-rich system by refinement in Event-B.

Yuliya Prokhorova; Linas Laibinis; Elena Troubitsyna; Kimmo Varpaaniemi; Timo Latvala

2012-01-01T23:59:59.000Z

117

Classical and Quantum Dynamics of Free Electromagnetic Laser Pulses  

E-Print Network (OSTI)

We discuss the use of a class of exact finite energy solutions to the vacuum source free Maxwell equations as models for multi- and single cycle laser pulses in classical interaction with relativistic charged point particles. These solutions are classified in terms of their chiral content and their influence on particular charge configurations in space. The results of such classical interactions motivate a particular quantum description of a freely propagating laser pulse in terms of an effective quantum Hamiltonian. The classical chiral states that evolve according to the classical vacuum Maxwell equations are now replaced by quantized bi-qutrit elements satisfying the Schrodinger equation. This description may offer a means to control and manipulate qu-trit states encoded into such laser pulses.

Goto, S; Walton, T J

2015-01-01T23:59:59.000Z

118

Compensated pulsed alternator  

DOE Patents (OSTI)

This invention relates to an electromechanical energy converter with inertial energy storage. The device, a single phase, two or multi-pole alternator with stationary field coils, and a rotating armature is provided. The rotor itself may be of laminated steel for slower pulses or for faster pulses should be nonmagnetic and electrically nonconductive in order to allow rapid penetration of the field as the armature coil rotates. The armature coil comprises a plurality of power generating conductors mounted on the rotor. The alternator may also include a stationary or counterrotating compensating coil to increase the output voltage thereof and to reduce the internal impedance of the alternator at the moment of peak outout. As the machine voltage rises sinusoidally, an external trigger switch is adapted to be closed at the appropriate time to create the desired output current from said alternator to an external load circuit, and as the output current passes through zero a self-commutating effect is provided to allow the switch to disconnect the generator from the external circuit.

Weldon, William F. (Austin, TX); Driga, Mircea D. (Austin, TX); Woodson, Herbert H. (Austin, TX)

1980-01-01T23:59:59.000Z

119

Switching power pulse system  

DOE Patents (OSTI)

A switching system for delivering pulses of power from a source to a load using a storage capacitor charged through a rectifier, and maintained charged to a reference voltage level by a transistor switch and voltage comparator. A thyristor is triggered to discharge the storage capacitor through a saturable reactor and fractional turn saturable transformer having a secondary to primary turn ratio N of n:l/n = n[sup 2]. The saturable reactor functions as a soaker'' while the thyristor reaches saturation, and then switches to a low impedance state. The saturable transformer functions as a switching transformer with high impedance while a load coupling capacitor charges, and then switches to a low impedance state to dump the charge of the storage capacitor into the load through the coupling capacitor. The transformer is comprised of a multilayer core having two secondary windings tightly wound and connected in parallel to add their output voltage and reduce output inductance, and a number of single turn windings connected in parallel at nodes for the primary winding, each single turn winding linking a different one of the layers of the multilayer core. The load may be comprised of a resistive beampipe for a linear particle accelerator and capacitance of a pulse forming network. To hold off discharge of the capacitance until it is fully charged, a saturable core is provided around the resistive beampipe to isolate the beampipe from the capacitance until it is fully charged. 5 figs.

Aaland, K.

1983-08-09T23:59:59.000Z

120

Bipolar pulse forming line  

DOE Patents (OSTI)

A bipolar pulse forming transmission line module for linear induction accelerators having first, second, third, fourth, and fifth planar conductors which form an interleaved stack with dielectric layers between the conductors. Each conductor has a first end, and a second end adjacent an acceleration axis. The first and second planar conductors are connected to each other at the second ends, the fourth and fifth planar conductors are connected to each other at the second ends, and the first and fifth planar conductors are connected to each other at the first ends via a shorting plate adjacent the first ends. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short a high voltage from the first end of the third planar conductor to the first end of the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

Rhodes, Mark A. (Pleasanton, CA)

2008-10-21T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Ultra-short pulse generator  

DOE Patents (OSTI)

An inexpensive pulse generating circuit is disclosed that generates ultra-short, 200 picosecond, and high voltage 100 kW, pulses suitable for wideband radar and other wideband applications. The circuit implements a nonlinear transmission line with series inductors and variable capacitors coupled to ground made from reverse biased diodes to sharpen and increase the amplitude of a high-voltage power MOSFET driver input pulse until it causes non-destructive transit time breakdown in a final avalanche shock wave diode, which increases and sharpens the pulse even more. 5 figures.

McEwan, T.E.

1993-12-28T23:59:59.000Z

122

Ultra-short pulse generator  

DOE Patents (OSTI)

An inexpensive pulse generating circuit is disclosed that generates ultra-short, 200 picosecond, and high voltage 100 kW, pulses suitable for wideband radar and other wideband applications. The circuit implements a nonlinear transmission line with series inductors and variable capacitors coupled to ground made from reverse biased diodes to sharpen and increase the amplitude of a high-voltage power MOSFET driver input pulse until it causes non-destructive transit time breakdown in a final avalanche shockwave diode, which increases and sharpens the pulse even more.

McEwan, Thomas E. (Livermore, CA)

1993-01-01T23:59:59.000Z

123

Deterministic passive mode locking of solid-state lasers  

SciTech Connect

An additional passive modulation is inserted in the cavity of a passive mode-locked Nd:glass laser in order to provide the conditions for a complete selectivity of the system. A rate equation approach shows that a stationary condition is reached in which only one pulse of the original fluctuation pattern is left. Computed simulations and experimental results are also shown confirming the theoretical predictions.

Martinez, O.E.; Spinelli, L.A.

1981-12-01T23:59:59.000Z

124

Photon detection efficiency of Geiger-mode avalanche photodiodes  

E-Print Network (OSTI)

The photon detection efficiencies of multi-pixel Geiger-mode avalanche photodiodes manufactured by different produ cers are estimated. A new fit method of the response spectra to low-intensity light, taking into ac count after-pulse and cross-talk effects is proposed to yield the initial number of photons. The value of photon detection efficiency is calculated using a calibrated photodetector as a reference.

Simonetta Gentile; Ekaterina Kuznetsova; Franco Meddi

2010-06-16T23:59:59.000Z

125

A current driven electromagnetic mode in sheared and toroidal configurations  

E-Print Network (OSTI)

The induced electric field in a tokamak drives a parallel electron current flow. In an inhomogeneous, finite beta plasma, when this electron flow is comparable to the ion thermal speed, the Alfven mode wave solutions of the electromagnetic gyrokinetic equation can become nearly purely growing kink modes. Using the new "low-flow" version of the gyrokinetic code GS2 developed for momentum transport studies [Barnes et al 2013 Phys. Rev. Lett. 111, 055005], we are able to model the effect of the induced parallel electric field on the electron distribution to study the destabilizing influence of current on stability. We identify high mode number kink modes in GS2 simulations and make comparisons to analytical theory in sheared magnetic geometry. We demonstrate reassuring agreement with analytical results both in terms of parametric dependences of mode frequencies and growth rates, and regarding the radial mode structure.

Pusztai, Istvn; Parra, Felix I; Barnes, Michael

2013-01-01T23:59:59.000Z

126

High Average Power, High Energy Short Pulse Fiber Laser System  

SciTech Connect

Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the issues associated chirped pulse amplification in optical fiber amplifier systems.

Messerly, M J

2007-11-13T23:59:59.000Z

127

Mevva ion source operated in purely gaseous mode  

SciTech Connect

We have operated a vacuum arc ion source in such a way as to form beams of purely gaseous ions. The vacuum arc configuration that is conventionally used to produce intense beams of metal ions was altered so as to form gaseous ion beams, with only minimal changes to the external circuitry and no changes at all internally to the ion source. In our experiments we formed beams from oxygen (O{sup +} and O{sub 2}{sup +}), nitrogen (N{sup +} and N{sub 2}{sup +}), argon (Ar{sup +}) and carbon dioxide (C{sup +}, CO{sub 2}{sup +}, O{sup +} and O{sub 2}{sup +}) at extraction voltage of 2 to 50 kV. We used a pulsed mode of operation, with beam pulses approximately 50 milliseconds long and repetition rate 10 pulses per second, for a duty cycle of about 50%. Downstream ion beam current as measured by a 5 cm diameter Faraday cup was typically 0.5 mA pulse or about 250 {micro}A time averaged. This time averaged beam current is very similar to that obtained for metal ions when the source is operated in the usual vacuum arc mode. Here we describe the modifications made to the source and the results of our investigations.

Yushkov, G.Y.; MacGill, R.A.; Brown, I. G.

2003-03-27T23:59:59.000Z

128

Influence of frequency scanning on the operation of pulsed lasers with external signal injection  

SciTech Connect

An analysis is made of the influence of variation of the detuning of the frequency of a resonator mode from that of an external injected signal on the operation of pulsed gas lasers. It is found when the detuning is varied with time there is an increase in the width of the locking region of a resonator mode in pulsed lasers. The results are given of numerical calculations of the dependences of the locking efficiency on the parameters on the injected signal and of the laser active medium.

Gapotchenko, N.I.; Likhanskii, V.V.; Napartovich, A.P.

1985-10-01T23:59:59.000Z

129

Hydraulic Pulse Drilling  

NLE Websites -- All DOE Office Websites (Extended Search)

REV DATE DESCRIPTION ORIGINATOR REVIEWED DATE REV DATE DESCRIPTION ORIGINATOR REVIEWED DATE 0 4/13/2004 Final Report Author: J. Kolle Hunter/Theimer 4/13/2004 Document No.: TR- 053 HydroPulse(tm) Drilling Final Report Prepared by J.J. Kolle April 2004 U.S. Department of Energy Cooperative Development Agreement No. DE-FC26-FT34367 Tempress Technologies, Inc. 18858 - 72 ND Ave S. Kent, WA 98032 Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not

130

Two stroke homogenous charge compression ignition engine with pulsed air supplier  

DOE Patents (OSTI)

A two stroke homogenous charge compression ignition engine includes a volume pulsed air supplier, such as a piston driven pump, for efficient scavenging. The usage of a homogenous charge tends to decrease emissions. The use of a volume pulsed air supplier in conjunction with conventional poppet type intake and exhaust valves results in a relatively efficient scavenging mode for the engine. The engine preferably includes features that permit valving event timing, air pulse event timing and injection event timing to be varied relative to engine crankshaft angle. The principle use of the invention lies in improving diesel engines.

Clarke, John M. (Chillicothe, IL)

2003-08-05T23:59:59.000Z

131

Switching power pulse system  

DOE Patents (OSTI)

A switching system for delivering pulses of power from a source (10) to a load (20) using a storage capacitor (C3) charged through a rectifier (D1, D2), and maintained charged to a reference voltage level by a transistor switch (Q1) and voltage comparator (12). A thyristor (22) is triggered to discharge the storage capacitor through a saturable reactor (18) and fractional turn saturable transformer (16) having a secondary to primary turn ratio N of n:l/n=n.sup.2. The saturable reactor (18) functions as a "soaker" while the thyristor reaches saturation, and then switches to a low impedance state. The saturable transformer functions as a switching transformer with high impedance while a load coupling capacitor (C4) charges, and then switches to a low impedance state to dump the charge of the storage capacitor (C3) into the load through the coupling capacitor (C4). The transformer is comprised of a multilayer core (26) having two secondary windings (28, 30) tightly wound and connected in parallel to add their output voltage and reduce output inductance, and a number of single turn windings connected in parallel at nodes (32, 34) for the primary winding, each single turn winding linking a different one of the layers of the multilayer core. The load may be comprised of a resistive beampipe (40) for a linear particle accelerator and capacitance of a pulse forming network (42). To hold off discharge of the capacitance until it is fully charged, a saturable core (44) is provided around the resistive beampipe (40) to isolate the beampipe from the capacitance (42) until it is fully charged.

Aaland, Kristian (Livermore, CA)

1983-01-01T23:59:59.000Z

132

Pulsed atmospheric fluidized bed combustion  

SciTech Connect

The general specifications for a Pulsed Atmospheric Fluidized Bed Combustor Design Report (PAFBC) plant are presented. The design tasks for the PAFBC are described in the following areas: Coal/Limestone preparation and feed system; pulse combustor; fluidized bed; boiler parts; and ash handling system.

Not Available

1992-08-01T23:59:59.000Z

133

Precision digital pulse phase generator  

DOE Patents (OSTI)

A timing generator comprises a crystal oscillator connected to provide an output reference pulse. A resistor-capacitor combination is connected to provide a variable-delay output pulse from an input connected to the crystal oscillator. A phase monitor is connected to provide duty-cycle representations of the reference and variable-delay output pulse phase. An operational amplifier drives a control voltage to the resistor-capacitor combination according to currents integrated from the phase monitor and injected into summing junctions. A digital-to-analog converter injects a control current into the summing junctions according to an input digital control code. A servo equilibrium results that provides a phase delay of the variable-delay output pulse to the output reference pulse that linearly depends on the input digital control code. 2 figs.

McEwan, T.E.

1996-10-08T23:59:59.000Z

134

Precision digital pulse phase generator  

DOE Patents (OSTI)

A timing generator comprises a crystal oscillator connected to provide an output reference pulse. A resistor-capacitor combination is connected to provide a variable-delay output pulse from an input connected to the crystal oscillator. A phase monitor is connected to provide duty-cycle representations of the reference and variable-delay output pulse phase. An operational amplifier drives a control voltage to the resistor-capacitor combination according to currents integrated from the phase monitor and injected into summing junctions. A digital-to-analog converter injects a control current into the summing junctions according to an input digital control code. A servo equilibrium results that provides a phase delay of the variable-delay output pulse to the output reference pulse that linearly depends on the input digital control code.

McEwan, Thomas E. (Livermore, CA)

1996-01-01T23:59:59.000Z

135

Distortionless optical pulse propagation in a three-level medium  

Science Journals Connector (OSTI)

We report on computer-generated solutions to the coupled matter-field equations which provide the first evidence for distortionless optical pulse propagation in an absorbing medium of three-level atoms. The associated phenomenon represents the three-level equivalent of self-induced transparency in two-level atoms. Results have application to the propagation of short, coherent optical pulses in a medium in which the atoms have two distinct transition frequencies in near resonance with the pulse carrier frequency. We relate in particular to the case of pulse propagation in a magnetically perturbed sodium vapor where the pulse carrier frequency is tuned near the frequencies of the well-known sodium D lines. Here we obtain particular solutions corresponding to three and five peak pulses with "areas" of approximately 6? and 10?, respectively. The solutions are strongly supported by a number of analytical results. In particular, simple algebraic relations are found which give the populations of the levels in terms of the field variables.

J. Higginbotham; R. T. Deck; D. G. Ellis

1977-11-01T23:59:59.000Z

136

Quantitative determination of energy enhanced interlayer transport in pulsed laser deposition of SrTiO3  

Science Journals Connector (OSTI)

We show that the analysis of single-shot surface x-ray diffraction transients in terms of time-dependent coverages allows quantitative determination of interlayer transport in pulsed-laser deposition of SrTiO3. The fast interlayer transport during and immediately after the arrival of the laser plume and before crystallization represents the dominant mechanism for redistribution of the deposited material that is completed on a ?s-range or faster time scale. Following crystallization interlayer transport is more than four orders of magnitude slower because it is driven only by sluggish thermally activated processes, which represent a small fraction of total interlayer transport that decreases with increasing laser repetition rate. The analysis of growth kinetics shows that it is fast interlayer transport driven by hyperthermal energy species and not thermal annealing that governs layer completion that determines the growth mode and the formation of atomically sharp interfaces in pulsed-laser deposition of epitaxial oxide films and similar energy-enhanced growth processes.

Gyula Eres; J. Z. Tischler; C. M. Rouleau; P. Zschack; H. M. Christen; B. C. Larson

2011-11-28T23:59:59.000Z

137

Dual-Mode Hybrid/Two-Mode Hybrid Accomplishment  

NLE Websites -- All DOE Office Websites (Extended Search)

Dual-Mode Hybrid/Two-Mode Hybrid Accomplishment Dual-Mode Hybrid/Two-Mode Hybrid Accomplishment DOE-funded research, in collaboration with Allison Buses and General Motors Corporation has led to the commercialization of a dramatically different hybrid transmission system for heavy-duty and light-duty applications. The Dual-Mode or Two-Mode hybrid system is an infinitely variable speed hybrid transmission that works with the engine and battery system and automatically chooses to operate in a parallel or series hybrid path to maximize efficiency and minimize emissions, fuel consumption and noise. Parallel and Series hybrid configurations are found on most hybrid vehicles today, both with their own pluses and minuses. The Dual- Mode/Two-Mode systems uses the positive characteristics from both systems to maximize fuel

138

Analysis of spectra of acoustic signals generated by high-power pulsed laser radiation propagating in the atmosphere. I. Spectra of local plasma formations  

Science Journals Connector (OSTI)

Results of theoretical and experimental investigations into the spectra of acoustic signals generated by high-power pulsed laser radiation propagating in the atmosphere in the breakdown mode are given in ... of a...

S. V. Shamanaev; L. G. Shamanaeva

2005-11-01T23:59:59.000Z

139

Optimizing the parameters of a system for pulsed pneumatic transportation of ash from electric precipitators at thermal power stations and putting this system into operation  

Science Journals Connector (OSTI)

Results from analysis of the effect of changes in the ash layer structure on the layers physical parameters are presented. Principles of designing a system for pneumatic transportation of ash in a pulsed mode...

V. K. Konovalov; O. V. Yashkin; V. V. Ermakov

2009-05-01T23:59:59.000Z

140

Resonance Excitation of Longitudinal High Order Modes in Project X Linac  

SciTech Connect

Results of simulation of power loss due to excitation of longitudinal high order modes (HOMs) in the accelerating superconducting RF system of CW linac of Project X are presented. Beam structures corresponding to the various modes of Project X operation are considered: CW regime for 3 GeV physics program; pulsed mode for neutrino experiments; and pulsed regime, when Project X linac operates as a driver for Neutrino Factory/Muon Collider. Power loss and associated heat load due to resonance excitation of longitudinal HOMs are shown to be small in all modes of operation. Conclusion is made that HOM couplers can be removed from the design of superconducting RF cavities of Project X linac.

Khabiboulline, T.N.; Sukhanov, A.AUTHOR = Awida, M.; Gonin, I.; Lunin, A.AUTHOR = Solyak, N.; Yakovlev, V.; /Fermilab

2012-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Fast Pulsing Neutron Generators for Security Application  

E-Print Network (OSTI)

FAST PULSING NEUTRON GENERATORS FOR SECURITY APPLICATION* Q.time/fast pulsing neutron generator is needed primarily forA compact neutron generator, currently being developed in

Ji, Q.

2010-01-01T23:59:59.000Z

142

Pulsed ion beam source  

DOE Patents (OSTI)

An improved pulsed ion beam source is disclosed having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center. 12 figs.

Greenly, J.B.

1997-08-12T23:59:59.000Z

143

A mechanical mode-stirred reverberation chamber with chaotic geometry  

E-Print Network (OSTI)

A previous research on multivariate approach to the calculation of reverberation chamber correlation matrices is used to calculate the number of independent positions in a mode-stirred reverberation chamber. Anomalies and counterintuitive behavior are observed in terms of number of correlated matrix elements with respect to increasing frequency. This is ascribed to the regular geometry forming the baseline cavity (screened room) of a reverberation chamber, responsible for localizing energy and preserving regular modes (bouncing ball modes). Smooth wall deformations are introduced in order to create underlying Lyapunov instability of rays and then destroy survived regular modes. Numerical full-wave simulations are performed for a reverberation chamber with corner hemispheres and (off-)center wall spherical caps. Field sampling is performed by moving a mechanical carousel stirrer. It is found that wave-chaos inspired baseline geometries improve chamber performances in terms of lowest usable frequencies and number of independent cavity realizations of mechanical stirrers.

Gabriele Gradoni; Franco Moglie; Valter Mariani Primiani

2014-07-06T23:59:59.000Z

144

Prefire identification for pulse power systems  

DOE Patents (OSTI)

Prefires in a high-power, high-frequency, multi-stage pulse generator are detected by a system having an EMI shielded pulse timing transmitter associated with and tailored to each stage of the pulse generator. Each pulse timing transmitter upon detection of a pulse triggers a laser diode to send an optical signal through a high frequency fiber optic cable to a pulse timing receiver which converts the optical signal to an electrical pulse. The electrical pulses from all pulse timing receivers are fed through an OR circuit to start a time interval measuring device and each electrical pulse is used to stop an individual channel in the measuring device thereby recording the firing sequence of the multi-stage pulse generator.

Longmire, Jerry L. (Los Alamos, NM); Thuot, Michael E. (Espanola, NM); Warren, David S. (Los Alamos, NM)

1985-01-01T23:59:59.000Z

145

Prefire identification for pulse-power systems  

DOE Patents (OSTI)

Prefires in a high-power, high-frequency, multi-stage pulse generator are detected by a system having an EMI shielded pulse timing transmitter associated with and tailored to each stage of the pulse generator. Each pulse timing transmitter upon detection of a pulse triggers a laser diode to send an optical signal through a high frequency fiber optic cable to a pulse timing receiver which converts the optical signal to an electrical pulse. The electrical pulses from all pulse timing receivers are fed through an OR circuit to start a time interval measuring device and each electrical pulse is used to stop an individual channel in the measuring device thereby recording the firing sequence of the multi-stage pulse generator.

Longmire, J.L.; Thuot, M.E.; Warren, D.S.

1982-08-23T23:59:59.000Z

146

Slow modes in Keplerian disks  

E-Print Network (OSTI)

Low-mass disks orbiting a massive body can support "slow" normal modes, in which the eigenfrequency is much less than the orbital frequency. Slow modes are lopsided, i.e., the azimuthal wavenumber m=1. We investigate the properties of slow modes, using softened self-gravity as a simple model for collective effects in the disk. We employ both the WKB approximation and numerical solutions of the linear eigenvalue equation. We find that all slow modes are stable. Discrete slow modes can be divided into two types, which we label g-modes and p-modes. The g-modes involve long leading and long trailing waves, have properties determined by the self-gravity of the disk, and are only present in narrow rings or in disks where the precession rate is dominated by an external potential. In contrast, the properties of p-modes are determined by the interplay of self-gravity and other collective effects. P-modes involve both long and short waves, and in the WKB approximation appear in degenerate leading/trailing pairs. Disks support a finite number---sometimes zero---of discrete slow modes, and a continuum of singular modes.

Scott Tremaine

2000-11-30T23:59:59.000Z

147

Ultrasonic flowmetering with reflected pulses  

E-Print Network (OSTI)

A transit time type ultrasonic flowmeter was tested with two different reflected pulse trajectories in flowing air at ambient conditions against an orifice meter. The flowmeter was designed to be highly accurate, to require ...

Hoyle, David C.

1984-01-01T23:59:59.000Z

148

Method and apparatus for improved efficiency in a pulse-width-modulated alternating current motor drive  

DOE Patents (OSTI)

A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements. 6 figs.

Konrad, C.E.; Boothe, R.W.

1996-01-23T23:59:59.000Z

149

Method and apparatus for improved efficiency in a pulse-width-modulated alternating current motor drive  

DOE Patents (OSTI)

A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements.

Konrad, Charles E. (Roanoke, VA); Boothe, Richard W. (Roanoke, VA)

1996-01-01T23:59:59.000Z

150

Method and apparatus for improved efficiency in a pulse-width-modulated alternating current motor drive  

DOE Patents (OSTI)

A scheme for optimizing the efficiency of an AC motor drive operated in a pulse-width-modulated mode provides that the modulation frequency of the power furnished to the motor is a function of commanded motor torque and is higher at lower torque requirements than at higher torque requirements.

Konrad, Charles E. (Roanoke, VA); Boothe, Richard W. (Roanoke, VA)

1994-01-01T23:59:59.000Z

151

Femtosecond laser pulse generation with a fiber taper embedded in carbon  

E-Print Network (OSTI)

Femtosecond laser pulse generation with a fiber taper embedded in carbon nanotube/polymer composite and demonstrate a new saturable absorber based on a fiber taper embedded in a carbon nanotube/polymer composite absorber. Using an embedded fiber-taper saturable absorber, we built an all-fiber mode-locked ring laser

Kieu, Khanh

152

Time resolved measurements of gratings photo-induced by femtosecond pulses in a  

E-Print Network (OSTI)

gratings with suppressed cladding modes made in SMF-28 with a femtosecond IR laser and a phase mask," IEEE on the formation of gratings photo-induced by femtosecond laser pulses in SF59 glass. Depending on the number. We demonstrate that the grating formation is not instantaneous and is produced by laser

Paris-Sud XI, Université de

153

A new procedure for static RAM evaluation under x-ray pulses  

SciTech Connect

An original method, to identify the initial patterns that are the most favorable to obtain upsets under X-ray pulses, has been developed on Static RAMs in the standby mode. The results obtained with these initial patterns are interesting in order to analyze the radiation induced failures.

Marec, R.; Gaillard, R. (Nucletudes S.A., Les Ulis (France)); Mary, P.; Fairbank, X. (LRBA, Vernon (France)); Ferrant, R. (Thomson-CSF Semiconducteurs Specifiques, Saint Egreve (France)); Palau, J.M.; Gasiot, J. (Univ. Montpellier (France). Centre Electronique de Montpellier)

1994-12-01T23:59:59.000Z

154

Void Detection in Foam with Knit Lines Using THz Pulse Interrogation H. T. Banks 1  

E-Print Network (OSTI)

Columbia. The detection of voids inside the Sprayed on Foam Insulation (SOFI) belonging to the ThermalVoid Detection in Foam with Knit Lines Using THz Pulse Interrogation H. T. Banks 1 and N. L. Gibson­8205 February 4, 2006 Abstract We model electromagnetic interrogation of a polyurethane foam using the TE mode

155

Lithium batteries for pulse power  

SciTech Connect

New designs of lithium batteries having bipolar construction and thin cell components possess the very low impedance that is necessary to deliver high-intensity current pulses. The R D and understanding of the fundamental properties of these pulse batteries have reached an advanced level. Ranges of 50--300 kW/kg specific power and 80--130 Wh/kg specific energy have been demonstrated with experimental high-temperature lithium alloy/transition-metal disulfide rechargeable bipolar batteries in repeated 1- to 100-ms long pulses. Other versions are designed for repetitive power bursts that may last up to 20 or 30 s and yet may attain high specific power (1--10 kW/kg). Primary high-temperature Li-alloy/FeS{sub 2} pulse batteries (thermal batteries) are already commercially available. Other high-temperature lithium systems may use chlorine or metal-oxide positive electrodes. Also under development are low-temperature pulse batteries: a 50-kW Li/SOCl{sub 2} primary batter and an all solid-state, polymer-electrolyte secondary battery. Such pulse batteries could find use in commercial and military applications in the near future. 21 refs., 8 figs.

Redey, L.

1990-01-01T23:59:59.000Z

156

Vacuum electron acceleration by using two variable frequency laser pulses  

SciTech Connect

A method is proposed for producing a relativistic electron bunch in vacuum via direct acceleration by using two frequency-chirped laser pulses. We consider the linearly polarized frequency-chiped Hermit-Gaussian 0, 0 mode lasers with linear chirp in which the local frequency varies linearly in time and space. Electron motion is investigated through a numerical simulation using a three-dimensional particle trajectory code in which the relativistic Newton's equations of motion with corresponding Lorentz force are solved. Two oblique laser pulses with proper chirp parameters and propagation angles are used for the electron acceleration along the z-axis. In this way, an electron initially at rest located at the origin could achieve high energy, ?=319 with the scattering angle of 1.02{sup ?} with respect to the z-axis. Moreover, the acceleration of an electron in different initial positions on each coordinate axis is investigated. It was found that this mechanism has the capability of producing high energy electron microbunches with low scattering angles. The energy gain of an electron initially located at some regions on each axis could be greatly enhanced compared to the single pulse acceleration. Furthermore, the scattering angle will be lowered compared to the acceleration by using laser pulses propagating along the z-axis.

Saberi, H.; Maraghechi, B. [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)] [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)

2013-12-15T23:59:59.000Z

157

Short-Term Energy Outlook  

Gasoline and Diesel Fuel Update (EIA)

(83/3Q) (83/3Q) Short-Term Energy Outlook iuarterly Projections August 1983 Energy Information Administration Washington, D.C. 20585 t rt jrt- .ort- iort- iort- iort- nort- lort- '.ort- ort- Tt- .-m .erm -Term -Term -Term -Term -Term -Term -Term -Term -Term -Term -Term -Term Term .-Term -Term xrm Energy Energy Energy Energy Energy Energy Energy Energy Energy Energy Energy Energy Energy Energy Energy Energy Energy Energy Energy Energy Energy ^nergy -OJ.UUK Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Outlook Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term Short-Term

158

Control of Analyte Electrolysis in Electrospray Ionization Mass Spectrometry Using Repetitively Pulsed High Voltage  

SciTech Connect

Analyte electrolysis using a repetitively pulsed high voltage ion source was investigated and compared to that using a regular, continuously operating direct current high voltage ion source in electrospray ionization mass spectrometry. The extent of analyte electrolysis was explored as a function of the length and frequency of the high voltage pulse using the model compound reserpine in positive ion mode. Using +5 kV as the maximum high voltage amplitude, reserpine was oxidized to its 2, 4, 6 and 8-electron oxidation products when direct current high voltage was employed. In contrast, when using a pulsed high voltage, oxidation of reserpine was eliminated by employing the appropriate high voltage pulse length and frequency. This effect was caused by inefficient mass transport of the analyte to the electrode surface during the duration of the high voltage pulse and the subsequent relaxation of the emitter electrode/ electrolyte interface during the time period when the high voltage was turned off. This mode of ESI source operation allows for analyte electrolysis to be quickly and simply switched on or off electronically via a change in voltage pulse variables.

Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

2011-01-01T23:59:59.000Z

159

EAST ion cyclotron resonance heating system for long pulse operation  

Science Journals Connector (OSTI)

Abstract Radio frequency (RF) power in the ion cyclotron range of frequencies (ICRF) is one of the primary auxiliary heating techniques for Experimental Advanced Superconducting Tokamak (EAST). The ICRF system for EAST has been developed to support long-pulse high-? advanced tokamak fusion physics experiments. The ICRF system is capable of delivering 12MW 1000-s RF power to the plasma through two antennas. The phasing between current straps of the antennas can be adjusted to optimize the RF power spectrum. The main technical features of the ICRF system are described. Each of the 8 ICRF transmitters has been successfully tested to 1.5MW for a wide range of frequency (2570MHz) on a dummy load. Part of the ICRF system was in operation during the EAST 2012 spring experimental campaign and a maximum power of 800kW (at 27MHz) lasting for 30s has been coupled for long pulse H mode operation.

Y.P. Zhao; X.J. Zhang; Y.Z. Mao; S. Yuan; D.Y. Xue; X. Deng; L. Wang; S.Q. Ju; Y. Cheng; C.M. Qin; G. Chen; Y. Lin; J.G. Li; B.N. Wan; Y.T. Song; F. Braun; R. Kumazawa; S. Wukitch

2014-01-01T23:59:59.000Z

160

Experimental observation and simulation of mode-locking phenomena in coupled-oscillator arrays  

E-Print Network (OSTI)

of operation. This has beenreferred to as a "mode-locked" system,after an anal- ogous situation in lasers.2 Further experimentation on this system has revealed that the pulse train is effectively scannedabovethe beenused to model complicated biological and neural activity, and have proved useful in power

York, Robert A.

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Helium Refrigerator Design for Pulsed Heat Load in Tokamaks  

SciTech Connect

Nuclear fusion reactors of the Tokamak type will be operated in a pulsed mode requiring the helium refrigerator to remove periodically large heat loads in time steps of approximately one hour. What are the necessary steps for a refrigerator to cope with such load variations?A series of numerical simulations has been performed indicating the possibility of an active refrigerator control with low exergetic losses. A basic comparison is made between the largest existing refrigerator sizes and the size required to service for example the ITER requirements.

Kuendig, A.; Schoenfeld, H. [Linde Kryotechnik AG, Dattlikonerstrasse 5, CH-8422 Pfungen (Switzerland)

2006-04-27T23:59:59.000Z

162

Scattering of coherent pulses on a two-level system  

E-Print Network (OSTI)

In this work, we consider a two-level system (TLS) coupled to a one-dimensional continuum of bosonic modes in a transmission line. Using the master equation approach, a method for determining the photon number distribution of the scattered field is outlined. Specifically, results for the reflected field when driving the TLS with a coherent pulse are given. While the one-photon probability is enhanced compared to the incident coherent field, the system is still not a good deterministic single-photon source. Extending the system to contain two separate transmission lines, however, output fields with one-photon probabilities close to unity can be reached.

Joel Lindkvist; Gran Johansson

2014-01-15T23:59:59.000Z

163

Impossibility of faithfully storing single photons with the three-pulse photon echo  

SciTech Connect

The three-pulse photon echo is a well-known technique to store intense light pulses in an inhomogeneously broadened atomic ensemble. This protocol is attractive because it is relatively simple and it is well suited for the storage of multiple temporal modes. Furthermore, it offers very long storage times, greater than the phase relaxation time. Here, we consider the three-pulse photon echo in both two- and three-level systems as a potential technique for the storage of light at the single-photon level. By explicit calculations, we show that the ratio between the echo signal corresponding to a single-photon input and the noise is smaller than one. This severely limits the achievable fidelity of the quantum state storage, making the three-pulse photon echo unsuitable for single-photon quantum memory.

Sangouard, Nicolas; Minar, Jiri; Afzelius, Mikael; Gisin, Nicolas; Riedmatten, Hugues de [Group of Applied Physics, University of Geneva, Geneva (Switzerland); Simon, Christoph; Tittel, Wolfgang [Institute for Quantum Information Science and Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Chaneliere, Thierry; Le Goueet, Jean-Louis [Laboratoire Aime Cotton, CNRS-UPR 3321, Universite Paris-Sud, F-91405 Orsay cedex (France)

2010-06-15T23:59:59.000Z

164

Flexure modes in carbon nanotubes  

Science Journals Connector (OSTI)

Phonons are calculated for single wall carbon nanotubes. Eigenvalues and eigenvectors are presented for armchair and zig-zag tubes. The model contains just three adjustable spring constants: two for first and second nearest neighbor directed bonds, and a third for radial bond-bending interactions. There are four low frequency modes at long wavelength: a longitudinal acoustical, a torsional mode, and two flexure modes.

G. D. Mahan and Gun Sang Jeon

2004-08-09T23:59:59.000Z

165

Pulse combustor with controllable oscillations  

DOE Patents (OSTI)

A pulse combustor having thermally induced pulse combustion in a continuously flowing system is described. The pulse combustor is fitted with at lease one elongated ceramic body which significantly increases the heat transfer area in the combustion chamber of the combustor. The ceramic body or bodies possess sufficient mass and heat capacity to ignite the fuel-air charge once the ceramic body or bodies are heated by conventional spark plug initiated combustion so as to provide repetitive ignition and combustion of sequentially introduced fuel-air charges without the assistance of the spark plug and the rapid quenching of the flame after each ignition in a controlled manner so as to provide a selective control over the oscillation frequency and amplitude. Additional control over the heat transfer in the combustion chamber is provided by employing heat exchange mechanisms for selectively heating or cooling the elongated ceramic body or bodies and/or the walls of the combustion chamber.

Richards, George A. (Morgantown, WV); Welter, Michael J. (Columbiana, OH); Morris, Gary J. (Morgantown, WV)

1992-01-01T23:59:59.000Z

166

Mach 5 bow shock control by a nanosecond pulse surface dielectric barrier discharge  

SciTech Connect

Bow shock perturbations in a Mach 5 air flow, produced by low-temperature, nanosecond pulse, and surface dielectric barrier discharge (DBD), are detected by phase-locked schlieren imaging. A diffuse nanosecond pulse discharge is generated in a DBD plasma actuator on a surface of a cylinder model placed in air flow in a small scale blow-down supersonic wind tunnel. Discharge energy coupled to the actuator is 7.3-7.8 mJ/pulse. Plasma temperature inferred from nitrogen emission spectra is a few tens of degrees higher than flow stagnation temperature, T = 340 {+-} 30 K. Phase-locked Schlieren images are used to detect compression waves generated by individual nanosecond discharge pulses near the actuator surface. The compression wave propagates upstream toward the baseline bow shock standing in front of the cylinder model. Interaction of the compression wave and the bow shock causes its displacement in the upstream direction, increasing shock stand-off distance by up to 25%. The compression wave speed behind the bow shock and the perturbed bow shock velocity are inferred from the Schlieren images. The effect of compression waves generated by nanosecond discharge pulses on shock stand-off distance is demonstrated in a single-pulse regime (at pulse repetition rates of a few hundred Hz) and in a quasi-continuous mode (using a two-pulse sequence at a pulse repetition rate of 100 kHz). The results demonstrate feasibility of hypersonic flow control by low-temperature, repetitive nanosecond pulse discharges.

Nishihara, M.; Takashima, K.; Rich, J. W.; Adamovich, I. V. [Michael A. Chaszeyka Nonequilibrium Thermodynamics Laboratories, Department of Mechanical and Aerospace Engineering, Ohio State University, Columbus, Ohio 43210 (United States)

2011-06-15T23:59:59.000Z

167

Mode propagation and absorption loss in metal-clad periodic optical waveguides  

SciTech Connect

In terms of the mode eigenvalue equations are field distributions, calculations are performed for Au/InGaAsP/InP, air/Au/InGaAsP/InP, and Au/DiO{sub 2}InGaAsP/InP periodic optical waveguides. On the basis of the computed results, the coupling property in the periodic structure is analyzed, the mode split and the mode band formation of both TE and TM guided modes are described, and the effects of the thickness of the metal cladding and the oxide buffer layer on mode propagation and absorption loss are discussed for TE and TM guided modes as well as for the TM surface-plasma mode. Furthermore, the conversion from the surface-plasma wave to the guided wave for the TM mode is explained for Au/SiO{sub 2}/InGaAsP/InP periodic structures. 27 refs., 8 figs.

Chunsheng Ma [Jilin Univ., Changchun (China)

1996-02-01T23:59:59.000Z

168

Mode Order Converter Using Tapered Multi-mode Interference Couplers  

E-Print Network (OSTI)

, and modes of guided light is essential for flexibility in photonic integrated circuit (PIC) design.3120) Integrated optics devices; (130.2790) Guided waves 1. Introduction Accommodating various sizes, shapes indices. One can define Am0 as the transmission of the fundamental mode in the output guide when exciting

Texas at Austin, University of

169

Standard Test Method for Measuring Dose for Use in Linear Accelerator Pulsed Radiation Effects Tests  

E-Print Network (OSTI)

1.1 This test method covers a calorimetric measurement of the total dose delivered in a single pulse of electrons from an electron linear accelerator or a flash X-ray machine (FXR, e-beam mode) used as an ionizing source in radiation-effects testing. The test method is designed for use with pulses of electrons in the energy range from 10 to 50 MeV and is only valid for cases in which both the calorimeter and the test specimen to be irradiated arethin compared to the range of these electrons in the materials of which they are constructed. 1.2 The procedure described can be used in those cases in which (1) the dose delivered in a single pulse is 5 Gy (matl) (500 rd (matl)) or greater, or (2) multiple pulses of a lower dose can be delivered in a short time compared to the thermal time constant of the calorimeter. Matl refers to the material of the calorimeter. The minimum dose per pulse that can be acceptably monitored depends on the variables of the particular test, including pulse rate, pulse uniformity...

American Society for Testing and Materials. Philadelphia

2011-01-01T23:59:59.000Z

170

Deterministic source of a train of indistinguishable single-photon pulses with single-atom-cavity system  

E-Print Network (OSTI)

We present a mechanism to produce indistinguishable single-photon pulses on demand from an optical cavity. The sequences of two laser pulses generate, at the two Raman transitions of a four-level atom, the same cavity-mode photons without repumping of the atom between photon generations. Photons are emitted from the cavity with near-unit efficiency in well-defined temporal modes of identical shapes controlled by the laser fields. The second order correlation function reveals the single-photon nature of the proposed source. A realistic setup for the experimental implementation is presented.

A. Gogyan; S. Gurin; H. -R. Jauslin; Yu. Malakyan

2010-05-01T23:59:59.000Z

171

Control of focusing fields in laser-plasma accelerators using higher-order modes E. Cormier-Michel,1,* E. Esarey,1  

E-Print Network (OSTI)

of intense laser pulses in plasma channels [1] has many applications, including x-ray lasers [2], highControl of focusing fields in laser-plasma accelerators using higher-order modes E. Cormier-order laser modes are analyzed as a method to control focusing forces and improve the electron bunch quality

Geddes, Cameron Guy Robinson

172

CHEMICAL ENGINEERING Fall Term Spring Term  

E-Print Network (OSTI)

to Engineering (FYE) 2 CHEM 112 General Chemistry 3 CHEM 111 General Chemistry 3 CHEG 112 Introduction I 3 CHEG 345 Chemical Engineering Laboratory I 3 CHEM 333 Organic Chemistry Laboratory 1 CHEM 332CHEMICAL ENGINEERING CURRICULUM FALL 2010 Fall Term Spring Term EGGG 101 Introduction

Lee, Kelvin H.

173

CHEMICAL ENGINEERING Fall Term Spring Term  

E-Print Network (OSTI)

CHEG 332 Chemical Engineering Kinetics 3 CHEG 342 Heat and Mass Transfer 3 CHEG 341 Fluid Mechanics 3CHEMICAL ENGINEERING CURRICULUM Fall Term Spring Term EGGG 101 Introduction to Engineering (FYE) 2 CHEG 112 Introduction to Chemical Engineering 3 CHEM 111 General Chemistry 3 CHEM 112 General Chemistry

Lee, Kelvin H.

174

Early-stage Power Grid Analysis for Uncertain Working Modes  

E-Print Network (OSTI)

Early-stage Power Grid Analysis for Uncertain Working Modes Haifeng Qian Department of ECE circuits are now reaching the 100-plus watt regime, and power delivery and power grid signal integrity have and Design Aids General Terms Algorithms, Performance, Design, Reliability Keywords Power grid, Supply

Sapatnekar, Sachin

175

Dynamic Modes of Nanoparticle Motion During Nanoprobe-based Manipulation  

E-Print Network (OSTI)

Dynamic Modes of Nanoparticle Motion During Nanoprobe-based Manipulation Afshin Tafazzoli and Metin -- In this paper, dynamic behavior of nanoparticle motion during nanoprobe-based manipulation is investigated behavior of nanoparticles. This would benefit us on tribological characterization of materials. Index Terms

Sitti, Metin

176

Cooperative pulses Technologieangebot /Technology offer  

E-Print Network (OSTI)

on issues from the national and international research and technology transfer. To market the patentsCooperative pulses Technologieangebot /Technology offer Referenz /Reference 2010-04E04 Branche at the TUM TUM ForTe Forschungsförderung & Technologie- transfer Patent- und Lizenzbüro Arcisstra?e 2180333

177

Mode-locked solid state lasers using diode laser excitation  

DOE Patents (OSTI)

A mode-locked laser employs a coupled-polarization scheme for efficient longitudinal pumping by reshaped laser diode bars. One or more dielectric polarizers are configured to reflect a pumping wavelength having a first polarization and to reflect a lasing wavelength having a second polarization. An asymmetric cavity provides relatively large beam spot sizes in gain medium to permit efficient coupling to a volume pumped by a laser diode bar. The cavity can include a collimation region with a controlled beam spot size for insertion of a saturable absorber and dispersion components. Beam spot size is selected to provide stable mode locking based on Kerr lensing. Pulse durations of less than 100 fs can be achieved in Yb:KGW.

Holtom, Gary R. (Boston, MA)

2012-03-06T23:59:59.000Z

178

Graphene saturable absorber for diode pumped Yb:Sc2SiO5 mode-locked laser  

Science Journals Connector (OSTI)

Abstract High-quality monolayer graphene was successfully fabricated by chemical vapor deposition technology. By using the graphene as a saturable absorber, the Yb:Sc2SiO5 crystal passively mode-locked laser was demonstrated for the first time. Stable mode-locked laser pulses were obtained with a repetition rate of 90.7MHz and an average output power of 480mW at the center wavelength of 1062.8nm. The maximum single pulse energy and the maximum peak power were 5.3nJ and 378W, respectively.

Wei Cai; Shouzhen Jiang; Shicai Xu; Yaqi Li; Jie Liu; Chun Li; Lihe Zheng; Liangbi Su; Jun Xu

2015-01-01T23:59:59.000Z

179

Dispersion compensation in chirped pulse amplification systems  

DOE Patents (OSTI)

A chirped pulse amplification system includes a laser source providing an input laser pulse along an optical path. The input laser pulse is characterized by a first temporal duration. The system also includes a multi-pass pulse stretcher disposed along the optical path. The multi-pass pulse stretcher includes a first set of mirrors operable to receive input light in a first plane and output light in a second plane parallel to the first plane and a first diffraction grating. The pulse stretcher also includes a second set of mirrors operable to receive light diffracted from the first diffraction grating and a second diffraction grating. The pulse stretcher further includes a reflective element operable to reflect light diffracted from the second diffraction grating. The system further includes an amplifier, a pulse compressor, and a passive dispersion compensator disposed along the optical path.

Bayramian, Andrew James; Molander, William A.

2014-07-15T23:59:59.000Z

180

Novette pulse-power-system description  

SciTech Connect

This paper is a summary of the pulse power systems for Novette; the flashlamp power system, the pulsers for the various optical shutters and the pulse power control system.

Gritton, D.G.; Christie, D.J.; Holloway, R.W.; Merritt, B.T.; Oicles, J.A.; Whitham, K.; Wilcox, R.B.

1983-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

ULTRASHORT LASER PULSE PROPAGATION IN WATER  

E-Print Network (OSTI)

We simulate ultrashort pulse propagation through water by numerical methods, which is a kind of optical communication research. Ultrashort pulses have been known to have non Beer-Lambert behavior, whereas continuous waves (CW) obey the Beer...

Byeon, Joong-Hyeok

2010-01-16T23:59:59.000Z

182

Ultrashort Pulse Propagation in the Linear Regime  

E-Print Network (OSTI)

First, we investigate the Bouguer-Lambert-Beer (BLB) law as applied to the transmission of ultrashort pulses through water in the linear absorption regime. We present a linear theory for propagation of ultrashort laser pulses, and related...

Wang, Jieyu

2010-07-14T23:59:59.000Z

183

Toward single-cycle optical pulses  

E-Print Network (OSTI)

Single-cycle optical pulses, the never-before-achieved regime, have a great potential for attosecond science and phase-sensitive nonlinear optics. To achieve single-cycle optical pulses by active synchronization, three ...

Kim, Jung-Won, 1976-

2004-01-01T23:59:59.000Z

184

Parametric doppler effect for laser pulses  

Science Journals Connector (OSTI)

Transformation of a light pulse reflected from an inhomogeneity moving in a medium with a frequency dispersion is analyzed. For a quasimonochromatic light pulse (with a narrow spectrum), simple expressions are...

N. N. Rosanov

2010-07-01T23:59:59.000Z

185

Progress In Understanding The Enhanced Petestal H-mode In NSTX  

SciTech Connect

ThIS paper describes the enhanced pedestal (EP) H-mode observed in the National Spherical Torus Experiment (NSTX). The defining characteristics of EP H-mode are given, namely i)transition after the L- to H-mode transition, ii) region of very steep ion temperature gradient, and iii) associated region of strong rotational shear. A newly observed long-pulse EP H-mode example shows quiescent behavior for as long as the heating and current drive sources are maintained. Cases are shown where the region of steep ion temperature gradient is located at the very edge, and cases where it is shifted up to 10 cm inward from the plasma edge; these cases are united by a common dependence of the ion temperature gradient on the toroidal rotation frequency shear. EP H-mode examples have been observed across a wide range of q95 and pedestal collisionality. No strong changes in the fluctuation amplitudes have been observed following the eP H-mode transition, and transport analysis indicates that the ion t hermal transport is comparable to or less than anticipated from a simple neoclassical transport model. Cases are shown where EP H-modes were reliably generated, through these low-q95 examples were difficult to sustain. A case where an externally triggered ELM precipitates the transition to EP H-mode is also shown, though an initial experiment designed to trigger EP-H-modes in this fashion was successful.

none,

2014-06-26T23:59:59.000Z

186

Recent advances in long-pulse high-confinement plasma operations in Experimental Advanced Superconducting Tokamak  

SciTech Connect

A long-pulse high confinement plasma regime known as H-mode is achieved in the Experimental Advanced Superconducting Tokamak (EAST) with a record duration over 30?s, sustained by Lower Hybrid wave Current Drive (LHCD) with advanced lithium wall conditioning and divertor pumping. This long-pulse H-mode plasma regime is characterized by the co-existence of a small Magneto-Hydrodynamic (MHD) instability, i.e., Edge Localized Modes (ELMs) and a continuous quasi-coherent MHD mode at the edge. We find that LHCD provides an intrinsic boundary control for ELMs, leading to a dramatic reduction in the transient power load on the vessel wall, compared to the standard Type I ELMs. LHCD also induces edge plasma ergodization, broadening heat deposition footprints, and the heat transport caused by ergodization can be actively controlled by regulating edge plasma conditions, thus providing a new means for stationary heat flux control. In addition, advanced tokamak scenarios have been newly developed for high-performance long-pulse plasma operations in the next EAST experimental campaign.

Guo, H. Y. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China) [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China); Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688 (United States); Li, J.; Wan, B. N., E-mail: bnwan@ipp.ac.cn; Gong, X. Z.; Xu, G. S.; Zhang, X. D.; Ding, S. Y.; Gan, K. F.; Hu, J. S.; Hu, L. Q.; Liu, S. C.; Qian, J. P.; Sun, Y. W.; Wang, H. Q.; Wang, L.; Xia, T. Y.; Xiao, B. J.; Zeng, L.; Zhao, Y. P. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China)] [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China); and others

2014-05-15T23:59:59.000Z

187

Submicrosecond pulsed atmospheric glow discharges sustained without dielectric barriers at kilohertz frequencies  

SciTech Connect

In this letter, the authors report the experimental observation of a large-volume atmospheric glow discharge sustained without dielectric barriers at 1 kHz. This barrier-free mode of operation is made possible with a submicrosecond pulsed excitation instead of the usual sinusoidal excitation. Its current-voltage characteristics are shown to be very different from conventional atmospheric dielectric barrier discharges, and its generation mechanism is studied with nanosecond resolved optical emission spectroscopy. The pulsed barrier-free atmospheric plasma is shown to produce very intense atomic oxygen emission line at 777 nm, up to one magnitude more intensive than that of a comparable atmospheric dielectric barrier discharge.

Walsh, J. L.; Shi, J. J.; Kong, M. G. [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)

2006-10-16T23:59:59.000Z

188

Response of C(60) and C(n) to ultrashort laser pulses  

E-Print Network (OSTI)

reliable numerical simulations. 0163-1829/2001/64~15!/153105~4!/$20.00 64 153105- ultrashort laser pulses Suhai,2 Th. Frauenheim,3 and R. E. Allen1 Physics, College Station, Texas 77843 re Biophysik, D-69120 Heidelberg, Germany retische Physik, D...-33098 Paderborn, Germany d 22 June 2001; published 21 September 2001! s of nonadiabatic processes, including the e of C60 and carbon chains to laser pulses demon- . For example, in C60 the pentagonal-pinch mode t at high fluence, and dimers...

Torralva, B.; Niehaus, TA; Elstner, M.; Suhai, S.; Frauenheim, T.; Allen, Roland E.

2001-01-01T23:59:59.000Z

189

PARAMETRIC CYCLE ANALYSIS FOR PULSE DETONATION ENGINES  

E-Print Network (OSTI)

PARAMETRIC CYCLE ANALYSIS FOR PULSE DETONATION ENGINES by HAIDER HEKIRI Presented to the Faculty, in particular, pulse detonation engines. Dr. Wilson taught me the basics of propulsion and made me enjoy #12;iii ABSTRACT PARAMETRIC CYCLE ANALYSIS FOR PULSE DETONATION ENGINES Publication No. ______ Haider

Texas at Arlington, University of

190

External kink modes as a model for MHD activity associated with ELMs  

SciTech Connect

Tokamak plasmas in the high confinement mode of operation are known to exhibit edge localized activity referred to as ELMs. A model is proposed for the underlying cause in terms of the external kink mode. The build up of the current density near the plasma edge is shown to decrease the shear in the safety-factor, q, profile and lead to destabilization of the kink mode. The role of the plasma geometry and equilibrium profiles is discussed.

Manickam, J.

1992-01-01T23:59:59.000Z

191

Mode synthesizing atomic force microscopy and mode-synthesizing sensing  

DOE Patents (OSTI)

A method of analyzing a sample that includes applying a first set of energies at a first set of frequencies to a sample and applying, simultaneously with the applying the first set of energies, a second set of energies at a second set of frequencies, wherein the first set of energies and the second set of energies form a multi-mode coupling. The method further includes detecting an effect of the multi-mode coupling.

Passian, Ali; Thundat, Thomas George; Tetard, Laurene

2013-05-17T23:59:59.000Z

192

Localized defect modes in graphene  

Science Journals Connector (OSTI)

We study the properties of localized vibrational modes associated with structural defects in a sheet of graphene. For the examples of the Stone-Wales defects, one- and two-atom vacancies, many-atom linear vacancies, and adatoms in a honeycomb lattice, we demonstrate that the local defect modes are characterized by stable oscillations with the frequencies lying outside the linear frequency bands of an ideal graphene. In the frequency spectral density of thermal oscillations, such localized defect modes lead to the additional peaks from the right side of the frequency band of the ideal sheet of graphene, which indicate the presence of defects in the graphene flakes.

Alexander V. Savin and Yuri S. Kivshar

2013-09-11T23:59:59.000Z

193

Pulsed Power for Solid-State Lasers  

SciTech Connect

Beginning in the early 1970s, a number of research and development efforts were undertaken at U.S. National Laboratories with a goal of developing high power lasers whose characteristics were suitable for investigating the feasibility of laser-driven fusion. A number of different laser systems were developed and tested at ever larger scale in pursuit of the optimum driver for laser fusion experiments. Each of these systems had associated with it a unique pulsed power option. A considerable amount of original and innovative engineering was carried out in support of these options. Ultimately, the Solid-state Laser approach was selected as the optimum driver for the application. Following this, the Laser Program at the Lawrence Livermore National Laboratory and the University of Rochester undertook aggressive efforts directed at developing the technology. In particular, at Lawrence Livermore National Laboratory, a series of laser systems beginning with the Cyclops laser and culminating in the present with the National Ignition Facility were developed and tested. As a result, a large amount of design information for solid-state laser pulsed power systems has been documented. Some of it is in the form of published papers, but most of it is buried in internal memoranda, engineering reports and LLNL annual reports. One of the goals of this book is to gather this information into a single useable format, such that it is easily accessed and understood by other engineers and physicists for use with future designs. It can also serve as a primer, which when seriously studied, makes the subsequent reading of original work and follow-up references considerably easier. While this book deals only with the solid-state laser pulsed power systems, in the bibliography we have included a representative cross section of papers and references from much of the very fine work carried out at other institutions in support of different laser approaches. Finally, in recent years, there has been a renewed interest in high-average-power solid-state glass lasers. Much of the prime power technology developed in support of this has definite applications in the long term for fusion power plant scenarios.

Gagnon, W; Albrecht, G; Trenholme, J; Newton, M

2007-04-19T23:59:59.000Z

194

Modelica Landing Gear Modelling and On-Ground Trajectory Tracking with Sliding Mode Control  

Science Journals Connector (OSTI)

A control system for an aircraft taxiing on ground based on sliding mode has been developed. The controller is capable to track the trajectory assigned in terms of longitudinal velocity and yaw rate and to dri...

Fabrizio Re

2011-01-01T23:59:59.000Z

195

Bearing Fault Detection in DFIG-Based Wind Turbines Using the First Intrinsic Mode Function  

E-Print Network (OSTI)

Bearing Fault Detection in DFIG-Based Wind Turbines Using the First Intrinsic Mode Function Y for bearing fault detection in DFIG-based wind turbines. The proposed method uses the first Intrinsic Mode Terms--Wind turbine, Doubly Fed Induction Generator (DFIG), fault detection, bearings, signal processing

Boyer, Edmond

196

Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems  

E-Print Network (OSTI)

Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems B. Beltran, T. Ahmed power generation in variable speed wind energy conversion systems (VS-WECS). These systems have two variations. Index Terms--Wind energy conversion system, power generation control, sliding mode control

Boyer, Edmond

197

Single-pulse Raman scattering study of triaminotrinitrobenzene under shock compression  

SciTech Connect

Pulsed-laser-excited Raman scattering methods have been used to examine the dynamic molecular-level response of an explosive molecule (triaminotrinitrobenzene, TATB) to sustained shock loading at a fused silica window interface. The anomalous behavior of Raman modes associated with nitro groups in the molecule (the 881-cm/sup /minus/1/ NO/sub 2/ deformation mode, the 1146 cm/sup /minus/1/ symmetric C-NO/sub s/ stretching mode, and the 1170-cm/sup /minus/1/ totally symmetric NO/sub 2/ stretching mode) is compared to results obtained under static high pressure. The shock compression data indicate that elevated temperatures act to restrain pressure-enhanced coupling of NO/sub 2/ and NH/sub 2/ groups in the molecule. Differences in the spectra obtained under static and dynamic high-pressure conditions are discussed in relation to the known insensitivity of TATB to shock initiation.

Trott, W.M.; Renlund, A.M.

1988-10-20T23:59:59.000Z

198

Unsplit bipolar pulse forming line  

DOE Patents (OSTI)

A bipolar pulse forming transmission line module and system for linear induction accelerators having first, second, third, and fourth planar conductors which form a sequentially arranged interleaved stack having opposing first and second ends, with dielectric layers between the conductors. The first and second planar conductors are connected to each other at the first end, and the first and fourth planar conductors are connected to each other at the second end via a shorting plate. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short at the first end a high voltage from the third planar conductor to the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

Rhodes, Mark A. (Pleasanton, CA)

2011-05-24T23:59:59.000Z

199

Ion Acceleration by Short Chirped Laser Pulses  

E-Print Network (OSTI)

Direct laser acceleration of ions by short frequency-chirped laser pulses is investigated theoretically. We demonstrate that intense beams of ions with a kinetic energy broadening of about 1 % can be generated. The chirping of the laser pulse allows the particles to gain kinetic energies of hundreds of MeVs, which is required for hadron cancer therapy, from pulses of energies of the order of 100 J. It is shown that few-cycle chirped pulses can accelerate ions more efficiently than long ones, i.e. higher ion kinetic energies are reached with the same amount of total electromagnetic pulse energy.

Li, Jian-Xing; Keitel, Christoph H; Harman, Zoltn

2015-01-01T23:59:59.000Z

200

Peeling mode relaxation ELM model  

SciTech Connect

This paper discusses an approach to modelling Edge Localised Modes (ELMs) in which toroidal peeling modes are envisaged to initiate a constrained relaxation of the tokamak outer region plasma. Relaxation produces both a flattened edge current profile (which tends to further destabilise a peeling mode), and a plasma-vacuum negative current sheet which has a counteracting stabilising influence; the balance that is struck between these two effects determines the radial extent (rE) of the ELM relaxed region. The model is sensitive to the precise position of the mode rational surfaces to the plasma surface and hence there is a 'deterministic scatter' in the results that has an accord with experimental data. The toroidal peeling stability criterion involves the edge pressure, and using this in conjunction with predictions of rE allows us to evaluate the ELM energy losses and compare with experiment. Predictions of trends with the edge safety factor and collisionality are also made.

Gimblett, C. G. [EURATOM/UKAEA Fusion Association, Culham Science Centre Abingdon, Oxon, OX14 3DB (United Kingdom)

2006-11-30T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Solid state pulsed power generator  

DOE Patents (OSTI)

A power generator includes one or more full bridge inverter modules coupled to a semiconductor opening switch (SOS) through an inductive resonant branch. Each module includes a plurality of switches that are switched in a fashion causing the one or more full bridge inverter modules to drive the semiconductor opening switch SOS through the resonant circuit to generate pulses to a load connected in parallel with the SOS.

Tao, Fengfeng; Saddoughi, Seyed Gholamali; Herbon, John Thomas

2014-02-11T23:59:59.000Z

202

Microwave pulse compression from a storage cavity with laser-induced switching  

DOE Patents (OSTI)

A laser-induced switch and a multiple cavity configuration are disclosed for producing high power microwave pulses. The microwave pulses are well controlled in wavelength and timing, with a quick rise time and a variable shape and power of the pulse. In addition, a method of reducing pre-pulse leakage to a low level is disclosed. Microwave energy is directed coherently to one or more cavities that stores the energy in a single mode, represented as a standing wave pattern. In order to switch the stored microwave energy out of the main cavity and into the branch waveguide, a laser-actuated switch is provided for the cavity. The switch includes a laser, associated optics for delivering the beam into the main cavity, and a switching gas positioned at an antinode in the main cavity. When actuated, the switching gas ionizes, creating a plasma, which becomes reflective to the microwave energy, changing the resonance of the cavity, and as a result the stored microwave energy is abruptly switched out of the cavity. The laser may directly pre-ionize the switching gas, or it may pump an impurity in the switching gas to an energy level which switches when a pre-selected cavity field is attained. Timing of switching the cavities is controlled by varying the pathlength of the actuating laser beam. For example, the pathlengths may be adjusted to output a single pulse of high power, or a series of quick lower power pulses.

Bolton, Paul R. (Menlo Park, CA)

1992-01-01T23:59:59.000Z

203

Existence of Metastable Kinetic Modes  

SciTech Connect

The nonlinear evolution of resonantly driven systems, such as suprathermal particle driven modes in magnetically confined plasmas, is shown to strongly depend on the existence and nature of an underlying damping mechanism. When background resonant damping is present, subcritical states can take place. In particular, purely nonlinear steady-state regimes are found, whose destabilization threshold and saturation levels are calculated and validated using numerical simulations. This nonlinear behavior can be of relevance for acoustic modes in magnetically confined plasmas.

Nguyen, C.; Luetjens, H.; Garbet, X.; Grandgirard, V.; Lesur, M. [Centre de Physique Theorique, CNRS-Ecole Polytechnique, Palaiseau (France); CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); JAEA, Higashi-Ueno 6-9-3, Taitou, Tokyo, 110-0015 (Japan)

2010-11-12T23:59:59.000Z

204

Phase space theory of Bose-Einstein condensates and time-dependent modes  

E-Print Network (OSTI)

A phase space theory approach for treating dynamical behaviour of Bose-Einstein condensates applicable to situations such as interferometry with BEC in time-dependent double well potentials is presented. Time-dependent mode functions are used, chosen so that one, two,.. highly occupied modes describe well the physics of interacting condensate bosons in time dependent potentials at well below the transition temperature. Time dependent mode annihilation, creation operators are represented by time dependent phase variables, but time independent total field annihilation, creation operators are represented by time independent field functions. Two situations are treated, one (mode theory) is where specific mode annihilation, creation operators and their related phase variables and distribution functions are dealt with, the other (field theory) is where only field creation, annihilation operators and their related field functions and distribution functionals are involved. The paper focuses on the hybrid approach, where the modes are divided up between condensate (highly occupied) modes and non-condensate (sparsely occupied) modes. It is found that there are extra terms in the Ito stochastic equations both for the stochastic phases and stochastic fields, involving coupling coefficients defined via overlap integrals between mode functions and their time derivatives. For the hybrid approach both the Fokker-Planck and functional Fokker-Planck equations differ from those derived via the correspondence rules, the drift vectors are unchanged but the diffusion matrices contain additional terms involving the coupling coefficients. Results are also presented for the combined approach where all the modes are treated as one set.

B. J. Dalton

2012-07-20T23:59:59.000Z

205

Theoretical aspects of the use of pulsed reflectometry in a spheromak plasma  

Science Journals Connector (OSTI)

Pulsed reflectometry using both ordinary (O) and extraordinary (X) modes has the potential of providing time- and space-resolved measurements of the electron density the magnitude of the magnetic field and the magnetic shear as a function of radius. Such a diagnostic also yields the current profile from the curl of the magnetic field. This research addresses theoretical issues associated with the use of reflectometry in the Sustained Spheromak Physics Experimentspheromakexperiment at the Lawrence Livermore National Laboratory. We have extended a reflectometry simulation model to accommodate O- and X-mode mixed polarization and linear mode conversion between the two polarizations. A WentzelKramersBrillouinJeffreys (WKBJ) formula for linear mode conversion agrees reasonably well with direct numerical solutions of the wave equation and we have reconstructed the magnetic pitchangle profile by matching the results of the WKBJ formula with the mode conversion data observed in simulations using a least-squares determination of coefficients in trial functions for the profile. The reflectometry data also yield information on fluctuations. Instrumental issues e.g. the effects of microwave mixers and filters on model reflectometry pulses have been examined to optimize the performance of the reflectometrydiagnostics.

Bruce I. Cohen; E. Bickford Hooper; M. C. Spang; C. W. Domier

1999-01-01T23:59:59.000Z

206

December 1985 / Vol. 10, No. 12 / OPTICS LETTERS 609 Picosecond pulse shaping by spectral phase and amplitude  

E-Print Network (OSTI)

The temporal profile of ultrashort optical pulses may be tailored by physically manipulating the phase, with a repetition rate of 100 MHz, are coupled into a 400-m length of single- mode, polarization-preserving optical.9 psec by using a double-pass grating pair.3'4 After a single pass, through the grating pair (grating

Purdue University

207

Evaluation of Some Blockcipher Modes of Operation  

E-Print Network (OSTI)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4. CBC, CFB, and OFB Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 5. CTR; many are widely used. The modes under consideration are the encryption schemes ECB, CBC, CFB, OFB, CTR

Rogaway, Phillip

208

Evaluation of Some Blockcipher Modes of Operation  

E-Print Network (OSTI)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4. CBC, CFB, and OFB Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 5. CTR are widely used. The modes under consideration are the encryption schemes ECB, CBC, CFB, OFB, CTR, and XTS

Rogaway, Phillip

209

Occupant satisfaction in mixed-mode buildings.  

E-Print Network (OSTI)

Strategies for Mixed-Mode Buildings, Summary Report, CenterCBE). 2006. Website: Mixed-Mode Building Case Studies.Department of Environmental Building Research Establishment

Brager, Gail; Baker, Lindsay

2008-01-01T23:59:59.000Z

210

Occupant satisfaction in mixed-mode buildings  

E-Print Network (OSTI)

Environmental Quality in Green Buildings. Indoor Air; 14 (Strategies for Mixed-Mode Buildings, Summary Report, CenterCBE). 2006. Website: Mixed-Mode Building Case Studies.

Brager, Gail; Baker, Lindsay

2009-01-01T23:59:59.000Z

211

Prospects of coherent control in turbid media: Bounds on focusing broadband laser pulses  

SciTech Connect

We study the prospects of controlling transmission of broadband and bichromatic laser pulses through turbid samples. The ability to focus transmitted broadband light is limited via both the scattering properties of the medium and the technical characteristics of the experimental setup. There are two time scales given by pulse stretching in the near- and far-field regions which define the maximum bandwidth of a pulse amenable to focusing. In the geometric-optics regime of wave propagation in the medium, a single setup can be optimal for focusing light at frequencies {omega} and n{omega} simultaneously, providing the basis for the 1+n coherent quantum control. Beyond the regime of geometric optics, we discuss a simple solution for the shaping, which provides the figure of merit for one's ability to simultaneously focus several transmission modes.

Shapiro, Evgeny A.; Drane, Thomas M. [Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1 (Canada); Milner, Valery [Department of Physics, The University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1 (Canada)

2011-11-15T23:59:59.000Z

212

Terms and Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

Terms and Conditions Terms and Conditions Terms and Conditions As a premier national research and development laboratory, LANL seeks to do business with qualified companies that offer value and high quality products and services. Contact Small Business Office (505) 667-4419 Email Use information below as guideline to doing business An "Appendix SFA-1" contains FAR and DEAR Clauses that are incorporated by reference into a particular subcontract. "Exhibit A General Conditions" are the general terms and conditions applicable to a particular subcontract. Note: The contents of the SFA-1 and Exhibit A (below) are not the only terms and conditions that will be in a LANS subcontract but represent the terms that generally do not change in a particular type of procurement. The

213

Development of an Ultra High Frequency Gyrotron with a Pulsed Magnet  

SciTech Connect

An ultra-high frequency gyrotron is being developed as a THz radiation source by using a pulsed magnet. We have achieved the highest field intensity of 20.2 T. High frequency operation at the second harmonic will achieve 1.01 THz; the corresponding cavity mode is TE6,11,1. On the other hand, an ultra-high power gyrotron with a pulsed magnet is also being developed as a millimeter to submillimeter wave radiation source. The gyrotron is a large orbit gyrotron (LOG) using an intense relativistic electron beam (IREB). A pulsed power generator 'ETIGO-IV' is applied for generation of the IREB. A prototype relativistic LOG was constructed for fundamental operation. The output of the LOG will achieve 144 GHz and 9 MW; the corresponding cavity mode is TE1,4,1. Cavities for 2nd and 4th harmonic operations were designed by numerical simulation for achievement of higher frequency. The progress of development for prototype high frequency gyrotrons with pulsed magnets is presented.

Idehara, T.; Kamada, M.; Tsuchiya, H.; Hayashi, T.; Agusu, La; Mitsudo, S.; Ogawa, I. [Research Center for Development of Far Infrared Region, University of Fukui, Bunkyo 3-9-1, Fukui-shi 910-8507 (Japan); Manuilov, V. N. [Research Center for Development of Far Infrared Region, University of Fukui, Bunkyo 3-9-1, Fukui-shi 910-8507 (Japan); Radiophysical Department of Nizhny Novgorod State University, 690005, Gagarin av., 23, Nizhny Novgorod (Russian Federation); Naito, K.; Yuyama, T.; Jiang, W.; Yatsui, K. [Extreme Energy-Density Research Institute, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka-shi, Niigata 940-2188 (Japan)

2006-01-03T23:59:59.000Z

214

Long-Term Surveillance  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Long-Term Surveillance Long-Term Surveillance Operations and Maintenance Fiscal Year 2013 Year-End Summary Report September 2013 LMS/ESL/S10692 ESL-RPT-2013-03 This page intentionally left blank LMS/ESL/S10692 ESL-RPT-2013-03 Long-Term Surveillance Operations and Maintenance Fiscal Year 2013 Year-End Summary Report September 2013 This page intentionally left blank U.S. Department of Energy Long-Term Surveillance Operations and Maintenance FY 2013 Year-End Summary Report September 2013 Doc. No. S10692 Page i Contents Abbreviations .................................................................................................................................. ii 1.0 Introduction ............................................................................................................................1

215

BPD Privacy Terms  

Energy.gov (U.S. Department of Energy (DOE))

The Building Performance Database Privacy Terms. This document must be reviewed and accepted when submitting data for use in the BPD.

216

Terms and Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

Testbed Results Current Testbed Research Proposal Process Terms and Conditions Dark Fiber Testbed Performance (perfSONAR) Software & Tools Development Partnerships...

217

Chaotic carrier pulse position modulation communication system and method  

DOE Patents (OSTI)

A chaotic carrier pulse position modulation communication system and method is disclosed. The system includes a transmitter and receiver having matched chaotic pulse regenerators. The chaotic pulse regenerator in the receiver produces a synchronized replica of a chaotic pulse train generated by the regenerator in the transmitter. The pulse train from the transmitter can therefore act as a carrier signal. Data is encoded by the transmitter through selectively altering the interpulse timing between pulses in the chaotic pulse train. The altered pulse train is transmitted as a pulse signal. The receiver can detect whether a particular interpulse interval in the pulse signal has been altered by reference to the synchronized replica it generates, and can therefore detect the data transmitted by the receiver. Preferably, the receiver predicts the earliest moment in time it can expect a next pulse after observation of at least two consecutive pulses. It then decodes the pulse signal beginning at a short time before expected arrival of a pulse.

Abarbanel, Henry D. I. (Del Mar, CA); Larson, Lawrence E. (Del Mar, CA); Rulkov, Nikolai F. (San Diego, CA); Sushchik, Mikhail M. (San Diego, CA); Tsimring, Lev S. (San Diego, CA); Volkovskii, Alexander R. (San Diego, CA)

2001-01-01T23:59:59.000Z

218

Two-pulse stimulated echo in magnets  

E-Print Network (OSTI)

The results of experimental study of two-pulse stimulated echo in ferromagnets of two types are presented. Ferromagnet Co and half-metal Co MnSi 2, in which a single-pulse echo formed by the distortion mechanism of the fronts of exciting pulse is also observed, are classified among the first type. Lithium ferrite and intermetal compound MnSb characterized by the absence of single-pulse echo in them - belong to the second type. For signals of two-pulse stimulated echo in the materials of the first type a short time and a long time of relaxations are observed. The short time is about the order of value shorter less than the spin-spin relaxation time. The long time is close to the transverse relaxation time of single-pulse echo formed by the distortion mechanism. The mechanisms that provide the possible interpretations of the peculiarities of the processes of nuclear magnetic relaxation are discussed.

Zviadadze, M D; Gegechkori, T O; Akhalkatsi, A M; Gavasheli, T A

2012-01-01T23:59:59.000Z

219

Sensing mode atomic force microscope  

DOE Patents (OSTI)

An atomic force microscope utilizes a pulse release system and improved method of operation to minimize contact forces between a probe tip affixed to a flexible cantilever and a specimen being measured. The pulse release system includes a magnetic particle affixed proximate the probe tip and an electromagnetic coil. When energized, the electromagnetic coil generates a magnetic field which applies a driving force on the magnetic particle sufficient to overcome adhesive forces exhibited between the probe tip and specimen. The atomic force microscope includes two independently displaceable piezo elements operable along a Z-axis. A controller drives the first Z-axis piezo element to provide a controlled approach between the probe tip and specimen up to a point of contact between the probe tip and specimen. The controller then drives the first Z-axis piezo element to withdraw the cantilever from the specimen. The controller also activates the pulse release system which drives the probe tip away from the specimen during withdrawal. Following withdrawal, the controller adjusts the height of the second Z-axis piezo element to maintain a substantially constant approach distance between successive samples.

Hough, Paul V. C. (Port Jefferson, NY); Wang, Chengpu (Upton, NY)

2003-01-01T23:59:59.000Z

220

Vibrational Modes of Adsorbed Atoms  

E-Print Network (OSTI)

for AronXe B. Neon Ar The lowest surface m ver g.ur ace mode branc mo d o' td 'th es of the " rin " ce e wit an adsorbate of modes assoc' tia ed with th e; there are for the ads stion, the bra h sorbate atoms I c 1.ons ranch labeled 2H s. n... , are the real ads teristic force con t tons ants for ad is evident that in Fi . 2 t "heavier" than th ig. the adsorbate is n e substrate M & terpretation b M, ) in tkis in- ecause the weaknes th l' ht ofth ds o ke adsorbate atoms (m, &m, IBRATIQNAI...

LAWRENCE, WR; Allen, Roland E.

1977-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Train of high-power femtosecond pulses: Probe wave in a gas of prepared atoms  

E-Print Network (OSTI)

We present a new method for generating a regular train of ultrashort optical pulses in a prepared two-level medium. The train develops from incident monochromatic probe radiation travelling in a medium of atoms, which are in a quantum mechanical superposition of dressed internal states. In the frame of used linear theory for the probe radiation, the energy of individual pulses is an exponentially growing function of atom density and of interaction cross section. Pulse repetition rate is determined by the generalized Rabi frequency and can be around 1 THz and greater. We also show that the terms, extra to the dipole approximation, endow the gas by a new property: non-saturating dependence of refractive index on the dressing monochromatic field intensity. Contribution of these nonsaturating terms can be compatible with the main dipole approximation in the wavelength region of about ten micrometers (the range of CO_2 laser) or larger.

Gevorg Muradyan; A. Zh. Muradyan

2009-08-21T23:59:59.000Z

222

PULSE DRYING EXPERIMENT AND BURNER CONSTRUCTION  

SciTech Connect

Non steady impingement heat transfer is measured. Impingement heating consumes 130 T-BTU/Yr in paper drying, but is only 25% thermally efficient. Pulse impingement is experimentally shown to enhance heat transfer by 2.8, and may deliver thermal efficiencies near 85%. Experimental results uncovered heat transfer deviations from steady theory and from previous investigators, indicating the need for further study and a better theoretical framework. The pulse burner is described, and its roll in pulse impingement is analyzed.

Robert States

2006-07-15T23:59:59.000Z

223

A pulse power source for tacitron photomultipliers  

SciTech Connect

The circuit of a pulse power supply for a photomultiplier with partial discharge of a capacitor through a divider is described. A TGU1-60/7 hydrogen tacitron is used as a commutator. The circuit parameters are: pulse amplitude, 3-6 kV; duration, 5-50 usec; and the photomultiplier divider current, 100 A. The circuit was used to pulse power an FEU-30 photomultiplier in the single-pulsemode and showed high reliability and simplicity in operation.

Aduev, B.P.; Salomatin, V.I.; Shkatov, V.T.

1985-10-01T23:59:59.000Z

224

Pulsed source ion implantation apparatus and method  

DOE Patents (OSTI)

A new pulsed plasma-immersion ion-implantation apparatus that implants ions in large irregularly shaped objects to controllable depth without overheating the target, minimizing voltage breakdown, and using a constant electrical bias applied to the target. Instead of pulsing the voltage applied to the target, the plasma source, for example a tungsten filament or a RF antenna, is pulsed. Both electrically conducting and insulating targets can be implanted.

Leung, Ka-Ngo (Hercules, CA)

1996-01-01T23:59:59.000Z

225

Pulsed source ion implantation apparatus and method  

DOE Patents (OSTI)

A new pulsed plasma-immersion ion-implantation apparatus that implants ions in large irregularly shaped objects to controllable depth without overheating the target, minimizing voltage breakdown, and using a constant electrical bias applied to the target. Instead of pulsing the voltage applied to the target, the plasma source, for example a tungsten filament or a RF antenna, is pulsed. Both electrically conducting and insulating targets can be implanted. 16 figs.

Leung, K.N.

1996-09-24T23:59:59.000Z

226

Microcomputer-controlled two-pulse generator  

SciTech Connect

The two-pulse generator generates trains of pulses whose parameters are specified by an Elektronika D3-28 microcomputer. The pulse durations are 1-128 usec, the intervals are 1-2048 usec, and the repetition periods are from 4 msec to 16 sec. In conjunction with an automated system, the generator allows automatic measurement of spin-spin and spin-lattice relaxation times in nuclear quadrupole resonance, setting of optimum pulse-train parameters (90-180 degrees), etc.

Boguslavskii, A.A.; Ermilov, V.V.; Pechenov, V.V.; Semin, G.K.; Shapiro, G.Y.

1986-07-01T23:59:59.000Z

227

bia-pulse | netl.doe.gov  

NLE Websites -- All DOE Office Websites (Extended Search)

4 Industrial Carbon Capture and Storage Clean Coal Power Initiative Power Plant Improvement Initiative Clean Coal Technology Demonstration Program FutureGen Pulse Combustor Design...

228

One-dimensional full wave simulation on XB mode conversion in electron cyclotron heating  

SciTech Connect

The XB mode conversion in electron cyclotron resonance frequency heating has been studied in detail through 1D full wave simulation. The field pattern depends on the density scale length, and the wave absorption near upper hybrid resonance is maximized beyond the R(X) mode cutoff density for optimized density scale length. The simulated mode conversion efficiency has been compared with that of an analytic formula, showing good agreements except for the phase dependent term of the X wave. The mode conversion efficiency is calculated for oblique injections as well, and it is found that the efficiency decreases as the injection angles increases. Short magnetic field scale length is confirmed to relax the short density scale length condition maximizing the XB mode conversion efficiency. Finally, the simulation code is used to analyze the mode conversion and power absorption of a pre-ionization plasma in versatile experiment spherical torus.

Kim, S. H., E-mail: shkim95@kaeri.re.kr [Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Lee, H. Y.; Jo, J. G.; Hwang, Y. S. [Seoul National University, Seoul 151-742 (Korea, Republic of)

2014-06-15T23:59:59.000Z

229

Brief Communication High temperature pulses decrease indirect chilling injury and elevate ATP levels  

E-Print Network (OSTI)

Brief Communication High temperature pulses decrease indirect chilling injury and elevate ATP: Received 20 December 2009 Accepted 8 March 2010 Available online 15 March 2010 Keywords: ATP Energy supply by determining survival rates and ATP levels for flies that had undergone continuous long-term exposure at 0 °C

Lee Jr., Richard E.

230

Coexistence of mixed mode multipactor  

SciTech Connect

Multipactor is a vacuum discharge based on secondary electron emission, and can manifest in many resonant and non-resonant modes. Where two or more types of multipactor coexist in the same device, it is found analytically that the one with the highest yield or the lowest order dominates.

Kishek, R. A. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States)

2012-12-15T23:59:59.000Z

231

The Light Curve and Internal Magnetic Field of the Mode-Switching Pulsar PSR B0943+10  

E-Print Network (OSTI)

A number of radio pulsars exhibit intriguing mode-switching behavior. Recent observations of PSR B0943+10 revealed correlated radio and X-ray mode switches, providing a new avenue for understanding this class of objects. The large X-ray pulse fraction observed during the radio quiet phase (Q mode) was previously interpreted as a result of changing obscuration of X-rays by dense magnetosphere plasma. We show that the large X-ray pulse fraction can be explained by including the beaming effect of a magnetic atmosphere, while remaining consistent with the dipole field geometry constrained by radio observations. We also explore a more extreme magnetic field configuration, where a magnetic dipole displaced from the center of the star produces two magnetic polar caps of different sizes and magnetic field strengths. These models are currently consistent with data in radio and X-rays and can be tested or constrained by future X-ray observations.

Storch, Natalia I; Lai, Dong; Bogdanov, Slavko; Heinke, Craig O

2014-01-01T23:59:59.000Z

232

Single-mode nonclassicality criteria via Holstein-Primakoff transformation  

E-Print Network (OSTI)

Recently, two quantifications for nonclassicality of a single-mode field are shown to be equivalent; (i) the rank of entanglement it can generate by a beam-splitter and (ii) the number of terms needed to expand it as superposition of coherent states. We show that nonclassicality criteria can be obtained with an alternative approach. The rank of two-mode entanglement among 2-level identical particles converges to the rank of single-mode nonclassicality within the Holstein-Primakoff transformation, at the large particle number limit. In particular, we show that the entanglement criterion of Hillery & Zubairy converges to the Mandel's $Q$-parameter which is used to reveal nonclassicality, and spin-squeezing criterion of S{\\o}rensen et al. converges to single-mode squeezing condition. We obtain additional nonclassicality criteria not existing in the literature. We also discuss if single-mode nonclassicality can be visualized as the entanglement of space generating the photons. Moreover, in a forthcoming study...

Tasgin, Mehmet Emre

2015-01-01T23:59:59.000Z

233

FY07 LDRD Final Report Precision, Split Beam, Chirped-Pulse, Seed Laser Technology  

SciTech Connect

The goal of this LDRD ER was to develop a robust and reliable technology to seed high-energy laser systems with chirped pulses that can be amplified to kilo-Joule energies and recompressed to sub-picosecond pulse widths creating extremely high peak powers suitable for petawatt class physics experiments. This LDRD project focused on the development of optical fiber laser technologies compatible with the current long pulse National Ignition Facility (NIF) seed laser. New technologies developed under this project include, high stability mode-locked fiber lasers, fiber based techniques for reduction of compressed pulse pedestals and prepulses, new compact stretchers based on chirped fiber Bragg gratings (CFBGs), new techniques for manipulation of chirped pulses prior to amplification and new high-energy fiber amplifiers. This project was highly successful and met virtually all of its goals. The National Ignition Campaign has found the results of this work to be very helpful. The LDRD developed system is being employed in experiments to engineer the Advanced Radiographic Capability (ARC) front end and the fully engineered version of the ARC Front End will employ much of the technology and techniques developed here.

Dawson, J W; Messerly, M J; Phan, H H; Crane, J K; Beach, R J; Siders, C W; Barty, C J

2009-11-12T23:59:59.000Z

234

Laser system using ultra-short laser pulses  

DOE Patents (OSTI)

A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

Dantus, Marcos (Okemos, MI); Lozovoy, Vadim V. (Okemos, MI); Comstock, Matthew (Milford, MI)

2009-10-27T23:59:59.000Z

235

Quantum-path control and isolated-attosecond-pulse generation using H2+ molecules with moving nuclei in few-cycle laser pulses  

Science Journals Connector (OSTI)

We theoretically investigate the high-order harmonic generation (HHG) and isolated-attosecond-pulse generation from a full one-dimensional (1D) model of H2+ molecule in 3-fs, 800-nm laser pulses by using numerical solutions of the non-Born-Oppenheimer time-dependent Schrdinger equation (TDSE). The numerical results with moving nuclei and the static nuclei are demonstrated. The harmonic spectrum from the 22nd to the cutoff becomes smooth and fewer modulations and an isolated-attosecond pulse with duration 129 as is generated when we consider the nuclear motion. We investigate the emission time of harmonics in terms of the time-frequency analysis, which shows that, with moving nuclei, the long trajectory is suppressed, and the short trajectories is enhanced. We apply the nuclear and electronic probability density and the simulation of classical electron trajectory to illustrate the physical mechanism of HHG.

Xin-Lei Ge; Tian Wang; Jing Guo; Xue-Shen Liu

2014-02-20T23:59:59.000Z

236

Complete radiative terms for the electron/electronic energy equation  

SciTech Connect

A derivation of the radiative terms in the electron/electronic energy equation is presented, properly accounting for the effects of absorption and emission of radiation on the individual energy modes of the gas. This electron/electronic energy equation with the complete radiative terms has successfully been used to model the radiation-dominated precursor ahead of the bow shock of a hypersonic vehicle entering the Earth`s atmosphere. 8 refs.

Stanley, S.A.; Carlson, L.A. [Univ of California, San Diego, CA (United States)

1994-10-01T23:59:59.000Z

237

Strong excitation of emitters in an impedance matched cavity: the area theorem, ?-pulse and self-induced transparency  

E-Print Network (OSTI)

I theoretically study the behavior of strong pulses exciting emitters inside a cavity. The ensemble is supposed to be inhomogeneously broadened and the cavity matched finding application in quantum storage of optical or RF photons. My analysis is based on energy and pulse area conservation rules predicting important distortions for specific areas. It is well supported by numerical simulations. I propose a qualitative interpretation in terms of slow-light. The analogy with the free space situation is remarkable.

Thierry Chanelire

2014-02-16T23:59:59.000Z

238

Terms and Conditions | EMSL  

NLE Websites -- All DOE Office Websites (Extended Search)

usage, consumables, materials, and EMSL staff travel. Under the terms of the DOE class waiver, users engaged in proprietary research are obligated to pay the full-cost recovery...

239

Document Type: Subject Terms  

E-Print Network (OSTI)

Title: Authors: Source: Document Type: Subject Terms: Abstract: Full Text Word Count: ISSN the department back on track. The action is to call a meeting of the team leaders and stress the urgency o

Major, Arkady

240

Terms and Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

Terms and Conditions Terms and Conditions R&D Overview 100G Testbed Testbed Description Testbed Results Current Testbed Research Proposal Process Terms and Conditions Virtual Circuits (OSCARS) Performance (perfSONAR) Tools Development Green Networking Authentication & Trust Federation (ATF) Partnerships Contact Us Technical Assistance: 1 800-33-ESnet (Inside the US) 1 800-333-7638 (Inside the US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: trouble@es.net Provide Web Site Feedback: info@es.net Terms and Conditions Researchers must provide ESnet copies of any articles, presentations, and publications based on testbed research for posting on the ESnet Testbed web site. All publications based on work conducted on the testbed must include the following statement:

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

High reliability low jitter pulse generator  

DOE Patents (OSTI)

A method and concomitant apparatus for generating pulses comprising providing a laser light source, disposing a voltage electrode between ground electrodes, generating laser sparks using the laser light source via laser spark gaps between the voltage electrode and the ground electrodes, and outputting pulses via one or more insulated ground connectors connected to the voltage electrode.

Savage, Mark E.; Stoltzfus, Brian S.

2013-01-01T23:59:59.000Z

242

PERFORMANCE ENHANCEMENTS ON A PULSED DETONATION ROCKET  

E-Print Network (OSTI)

PERFORMANCE ENHANCEMENTS ON A PULSED DETONATION ROCKET The members of the Committee approve #12;To Grandma and Grandpa #12;PERFORMANCE ENHANCEMENTS ON A PULSED DETONATION ROCKET by JASON MATTHEW DETONATION ROCKET Publication No. Jason Matthew Meyers, M.S. The University of Texas at Arlington, 2002

Texas at Arlington, University of

243

Coherence as ultrashort pulse train generator  

E-Print Network (OSTI)

Intense, well-controlled regular light pulse trains start to play a crucial role in many fields of physics. We theoretically demonstrate a very simple and robust technique for generating such periodic ultrashort pulses from a continuous probe wave which propagates in a dispersive thermal gas media.

Gevorg Muradyan; Mariam Hovhannisyan

2010-07-08T23:59:59.000Z

244

Pulse Combustion Characteristics of Various Gaseous Fuels  

Science Journals Connector (OSTI)

Pulse combustion performance of fuels with low and high heating values is also compared. ... Selected gaseous fuels such as low molecular weight hydrocarbons, high molecular weight hydrocarbons, biofuels, and mixed fuels are tested for pulse combustion, and their operational properties are presented and compared. ... Heat transfer data for several exptl. ...

Wu Zhonghua; Arun S. Mujumdar

2008-02-06T23:59:59.000Z

245

Heart Physiology Lab Part 1: Pulse Rate  

E-Print Network (OSTI)

Heart Physiology Lab Part 1: Pulse Rate Measure your pulse in each of the following conditions (in in the class. You may use Table 1 in the Heart Physiology Worksheet for this, if you wish. Once you have all of the class averages for each measurement. You may use Graph 1 in the Heart Physiology Worksheet for this

Loughry, Jim

246

Harmonic generation with temporally focused ultrashort pulses  

E-Print Network (OSTI)

Harmonic generation with temporally focused ultrashort pulses Dan Oron and Yaron Silberberg of harmonic generation with temporally focused ultrashort pulses are explored both theoreti- cally and experimentally. Analyzing the phase-matching conditions for harmonic generation we find a corre- spondence

Silberberg, Yaron

247

Infrared pulse characterization using four-wave mixing inside a few cycle pulse filament in air  

SciTech Connect

We demonstrate a four-wave mixing (FWM) technique to measure near- and mid-infrared (IR) laser pulse shapes in time domain. Few cycle 800?nm laser pulses were synchronized with the IR pulse and focused colinearly to generate a plasma filament in air. Second harmonic radiation around 400?nm was generated through FWM, with a yield proportional to the IR pulse intensity. Excellent signal to noise ratio was observed from 2.1??m to 18??m. With proper phase stabilization of the IR beam, this technique is a promising step toward direct electric field sensing of near-IR pulses in air.

Marceau, Claude, E-mail: claude.marceau.2@ulaval.ca; Thomas, Steven; Kassimi, Yacine; Gingras, Guillaume; Witzel, Bernd [Centre d'Optique, Photonique et Laser, Pavillon d'optique-photonique Qubec (Qubec), Universit Laval, Qubec G1V 0A6 (Canada)

2014-02-03T23:59:59.000Z

248

Digital gate pulse generator for cycloconverter control  

DOE Patents (OSTI)

The present invention provides a digital gate pulse generator which controls the output of a cycloconverter used for electrical power conversion applications by determining the timing and delivery of the firing pulses to the switching devices in the cycloconverter. Previous gate pulse generators have been built with largely analog or discrete digital circuitry which require many precision components and periodic adjustment. The gate pulse generator of the present invention utilizes digital techniques and a predetermined series of values to develop the necessary timing signals for firing the switching device. Each timing signal is compared with a reference signal to determine the exact firing time. The present invention is significantly more compact than previous gate pulse generators, responds quickly to changes in the output demand and requires only one precision component and no adjustments.

Klein, Frederick F. (Monroeville, PA); Mutone, Gioacchino A. (Pleasant Hills, PA)

1989-01-01T23:59:59.000Z

249

AN UPDATE ON NIF PULSED POWER  

SciTech Connect

The National Ignition Facility (NIF) is a 192-beam laser fusion driver operating at Lawrence Livermore National Laboratory. NIF relies on three large-scale pulsed power systems to achieve its goals: the Power Conditioning Unit (PCU), which provides flashlamp excitation for the laser's injection system; the Power Conditioning System (PCS), which provides the multi-megajoule pulsed excitation required to drive flashlamps in the laser's optical amplifiers; and the Plasma Electrode Pockels Cell (PEPC), which enables NIF to take advantage of a fourpass main amplifier. Years of production, installation, and commissioning of the three NIF pulsed power systems are now complete. Seven-day-per-week operation of the laser has commenced, with the three pulsed power systems providing routine support of laser operations. We present the details of the status and operational experience associated with the three systems along with a projection of the future for NIF pulsed power.

Arnold, P A; James, G F; Petersen, D E; Pendleton, D L; McHale, G B; Barbosa, F; Runtal, A S; Stratton, P L

2009-06-22T23:59:59.000Z

250

Higher mode stability in spheromak equilibria  

Science Journals Connector (OSTI)

Spheromak equilibria with current profiles varying from peaked to hollow are analyzed for higher mode stability using a linear magnetohydrodynamic(MHD) code. For a cylindrical flux conserver with a radius equal to length the n=2 m=2 mode is found to be marginally unstable for the same hollow current profile as the n=1 m=1 mode. While the growth rate for this n=2 mode is much lower than the n=1 mode the presence of the n=2 mode may explain experimentally observed relaxation phenomena involving short wavelength turbulence in spheromak equilibria with sufficiently hollow current profiles.

U. Shumlak; T. R. Jarboe

1999-01-01T23:59:59.000Z

251

Cloud point determination using a thickness shear mode resonator  

SciTech Connect

Crude oils and crude oil products contain substantial amounts of petroleum waxes, consisting of a distribution of high molecular weight hydrocarbons. These waxes or paraffins have limited solubility in oil and tend to precipitate out at a temperature determined by the concentration and constituents of the wax. Precipitation and deposition of wax results in narrowing of pipelines, making crude oil recovery difficult. A parameter of practical importance is the wax precipitation temperature, traditionally known as the cloudpoint, at which visible crystallization occurs. Deposition problems arise in oil field operations at or below this temperature. Several techniques can be used to determine the cloud point: (1) visual observation, (2) viscosity measurement, (3) differential thermal analysis, and (4) pulsed nuclear magnetic resonance. This report describes a method for determination of cloud point with the use of a thickness shear mode resonator.

Spates, J.J. [Ktech Corp., Albuquerque, NM (United States); Martin, S.J.; Mansure, A.J. [Sandia National Lab., Albuquerque, NM (United States); Germer, J.W. [Petrolite Corp., St. Louis, MO (United States)

1995-12-31T23:59:59.000Z

252

Relationship Between Onset Thresholds, Trigger Types, and Rotation Shear for the m/n=2/1 Neoclassical Tearing Mode in a High-? Spherical Torus  

SciTech Connect

The onset conditions for the m/n=2/1 neoclassical tearing mode (NTM) are studied in terms of neoclassical drive, triggering instabilities, and toroidal rotation or rotation shear, in the spherical torus NSTX [M. Ono, et al., Nuclear Fusion 40, 557 (2000)]. There are three typical onset conditions for these modes, given in order of increasing neoclassical drive required for mode onset: triggering by energetic particle modes, triggering by edge localized modes, and cases where the modes appear to grow without a trigger. In all cases, the required drive increases with toroidal rotation shear, implying a stabilizing effect from the shear.

Gerhardt, S. P.; Brennan, D. P.; Buttery, R.; La Haye, R. J.; Sabbagh, S.; Strait, E.; Bell, M.; Bell, R.; Fredrickson, E.; Gates, D.; LeBlanc, B.; Menard, J.; Stutman, D.; Tritz, K.; Yuh, H.

2009-02-24T23:59:59.000Z

253

Behavior of reflected extraordinary mode in the fundamental electron cyclotron heating and current drive in JT-60U  

Science Journals Connector (OSTI)

Unwanted X-mode behavior in the fundamental harmonic electron cyclotron (EC) wave launching from the low field side with an oblique toroidal injection angle is experimentally studied on JT-60U by changing the poloidal injection angle. It is found that there is a critical region in the poloidal injection angle to cause the rise in vacuum pressure at the NBI port adjacent to the ECRF antenna port. The typical EC beam power is about 1 MW and the pulse length is 3 s in this experiment. The ray-trace calculation indicates that the X-mode launched from the low field side is guided into the NBI port after reflection at the cut-off layer for the critical poloidal injection angle. The results suggest that the O-mode injection with quite high mode purity, that is, with a very low fraction of X-mode is required for the avoidance of the overheat of the in-vessel components due to the reflected X-mode in the case of the EC beam launching from the low field side, especially for long pulse operation.

K. Kajiwara; S. Moriyama; K. Takahashi; Y. Ikeda; M. Seki; T. Fujii

2003-01-01T23:59:59.000Z

254

Real-time multi-mode neutron multiplicity counter  

DOE Patents (OSTI)

Embodiments are directed to a digital data acquisition method that collects data regarding nuclear fission at high rates and performs real-time preprocessing of large volumes of data into directly useable forms for use in a system that performs non-destructive assaying of nuclear material and assemblies for mass and multiplication of special nuclear material (SNM). Pulses from a multi-detector array are fed in parallel to individual inputs that are tied to individual bits in a digital word. Data is collected by loading a word at the individual bit level in parallel, to reduce the latency associated with current shift-register systems. The word is read at regular intervals, all bits simultaneously, with no manipulation. The word is passed to a number of storage locations for subsequent processing, thereby removing the front-end problem of pulse pileup. The word is used simultaneously in several internal processing schemes that assemble the data in a number of more directly useable forms. The detector includes a multi-mode counter that executes a number of different count algorithms in parallel to determine different attributes of the count data.

Rowland, Mark S; Alvarez, Raymond A

2013-02-26T23:59:59.000Z

255

Block Cipher Modes Cetin Kaya Koc  

E-Print Network (OSTI)

Confidentiality Modes Five confidentiality modes: ECB, CBC, CFB, OFB, and CTR ECB: Electronic Codebook CBC: Cipher Block Chaining CFB: Cipher Feedback OFB: Output Feedback CTR: Counter Ko�c (http

256

Distinct Modes of Internal Variability in the Global Meridional Overturning Circulation Associated with the Southern Hemisphere Westerly Winds  

Science Journals Connector (OSTI)

The internal variability of the global meridional overturning circulation (GMOC) in long-term integration of the earth system model Community Earth System Models (COSMOS) is examined in this study. Two distinct modes of the GMOC, which are closely ...

Wei Wei; Gerrit Lohmann; Mihai Dima

2012-05-01T23:59:59.000Z

257

Pulsed laser irradiation of metal multilayers.  

SciTech Connect

Vapor-deposited, exothermic metal-metal multilayer foils are an ideal class of materials for detailed investigations of pulsed laser-ignited chemical reactions. Created in a pristine vacuum environment by sputter deposition, these high purity materials have well-defined reactant layer thicknesses between 1 and 1000 nm, minimal void density and intimate contact between layers. Provided that layer thicknesses are made small, some reactive metal-metal multilayer foils can be ignited at a point by laser irradiation and exhibit subsequent high-temperature, self-propagating synthesis. With this presentation, we describe the pulsed laser-induced ignition characteristics of a single multilayer system (equiatomic Al/Pt) that exhibits self-propagating synthesis. We show that the thresholds for ignition are dependent on (i) multilayer design and (ii) laser pulse duration. With regard to multilayer design effects on ignition, there is a large range of multilayer periodicity over which ignition threshold decreases as layer thicknesses are made small. We attribute this trend of decreased ignition threshold to reduced mass transport diffusion lengths required for rapid exothermic mixing. With regard to pulse duration effects, we have determined how ignition threshold of a single Al/Pt multilayer varies with pulse duration from 10{sup -2} to {approx} 10{sup -13} sec (wavelength and spot size are held constant). A higher laser fluence is required for ignition when using a single laser pulse {approx} 100 fs or 1 ps compared with nanosecond or microsecond exposure, and we attribute this, in part, to the effects of reactive material being ablated when using the shorter pulse durations. To further understand these trends and other pulsed laser-based processes, our discussion concludes with an analysis of the heat-affected depths in multilayers as a function of pulse duration.

Adams, David Price; McDonald, Joel Patrick

2010-11-01T23:59:59.000Z

258

System for generating shaped optical pulses and measuring optical pulses using spectral beam deflection (SBD)  

DOE Patents (OSTI)

A temporally shaped or modified optical output pulse is generated from a bandwidth-encoded optical input pulse in a system in which the input pulse is in the form of a beam which is spectrally spread into components contained within the bandwidth, followed by deflection of the spectrally spread beam (SBD) thereby spatially mapping the components in correspondence with the temporal input pulse profile in the focal plane of a lens, and by spatially selective attenuation of selected components in that focal plane. The shaped or modified optical output pulse is then reconstructed from the attenuated spectral components. The pulse-shaping system is particularly useful for generating optical pulses of selected temporal shape over a wide range of pulse duration, such pulses finding application in the fields of optical communication, optical recording and data storage, atomic and molecular spectroscopy and laser fusion. An optical streak camera is also provided which uses SBD to display the beam intensity in the focal plane as a function of time during the input pulse. 10 figures.

Skupsky, S.; Kessler, T.J.; Letzring, S.A.

1993-11-16T23:59:59.000Z

259

Optical waveguides having flattened high order modes  

DOE Patents (OSTI)

A deterministic methodology is provided for designing optical fibers that support field-flattened, ring-like higher order modes. The effective and group indices of its modes can be tuned by adjusting the widths of the guide's field-flattened layers or the average index of certain groups of layers. The approach outlined here provides a path to designing fibers that simultaneously have large mode areas and large separations between the propagation constants of its modes.

Messerly, Michael Joseph; Beach, Raymond John; Heebner, John Edward; Dawson, Jay Walter; Pax, Paul Henry

2014-08-05T23:59:59.000Z

260

Nox reduction system utilizing pulsed hydrocarbon injection  

DOE Patents (OSTI)

Hydrocarbon co-reductants, such as diesel fuel, are added by pulsed injection to internal combustion engine exhaust to reduce exhaust NO.sub.x to N.sub.2 in the presence of a catalyst. Exhaust NO.sub.x reduction of at least 50% in the emissions is achieved with the addition of less than 5% fuel as a source of the hydrocarbon co-reductants. By means of pulsing the hydrocarbon flow, the amount of pulsed hydrocarbon vapor (itself a pollutant) can be minimized relative to the amount of NO.sub.x species removed.

Brusasco, Raymond M. (Livermore, CA); Penetrante, Bernardino M. (San Ramon, CA); Vogtlin, George E. (Fremont, CA); Merritt, Bernard T. (Livermore, CA)

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Vehicle Technologies Office: Long-Term Exploratory Research  

NLE Websites -- All DOE Office Websites (Extended Search)

Long-Term Exploratory Research Long-Term Exploratory Research Long-term research addresses the chemical instabilities that impede the development of advanced batteries. Researchers focus on synthesizing novel components into battery cells and determining failure modes, while maintaining strengths in materials synthesis and evaluation, advanced diagnostics, and improved electrochemical model development. Goals include developing a better understanding of why systems fail, creating models that predict system failure and permit system optimization, and investigating new and promising materials. The work concentrates on six research areas: Advanced cell chemistry, Non-carbonaceous anodes, New electrolytes, Novel cathode materials, Advanced diagnostics and analytical methods, and Phenomenological modeling.

262

Predicting non-isometric fatigue induced by electrical stimulation pulse trains as a function of pulse duration  

E-Print Network (OSTI)

electrical stimulation pulse trains as a function of pulseelectrical stimulation pulse trains as a function of pulsestimulation parameters (train duration, interpulse interval,

Marion, M Susan; Wexler, Anthony S; Hull, Maury L

2013-01-01T23:59:59.000Z

263

Pruning Simply Typed -terms  

Science Journals Connector (OSTI)

......looking for the smallest pout > r /) 6out > //_ gout > B,, c/) pout > p such that: pout...and pout h ^out . Bout b y minimaiKy o f tout gout pout w e deduce; 6out gout gout^ pout < pout Pruning Simply Typed A-terms......

STEFANO BERARDI

1996-10-01T23:59:59.000Z

264

Nonlinear evolution of the resistive interchange mode in the cylindrical spheromak  

Science Journals Connector (OSTI)

Results are presented of a study of various aspects of the single helicity nonlinear development of the resistive interchange mode in the cylindrical spheromak. A formulation of the helically symmetric resistive magnetohydrodynamic (MHD) equations that partially separates the ideal MHD characteristics is developed. Mode saturation can occur because of the quasilinear flattening of the pressure profile in the vicinity of the mode rational surface. However this saturation process is defeated when the plasma overheats and in regions of the plasma where the shear is low. Finite fluid compression has significant and optimistic consequences on the long?term nonlinear behavior of this mode. For a tearing mode stable cylindrical spheromak equilibrium configuration with an axial beta value of 6% complete overlap of the m=1 islands occurs in about 3% of the resistive skin time for a magnetic Reynolds number of S=105. For typical parameters of the S?1 device at Princeton this time corresponds to nearly one millisecond.

J. DeLucia; S. C. Jardin

1984-01-01T23:59:59.000Z

265

Vibration modes of giant gravitons  

Science Journals Connector (OSTI)

We examine the spectrum of small vibrations of giant gravitons when the gravitons expand in antide Sitter space and when they expand on the sphere. For any given angular harmonic, the modes are found to have frequencies related to the curvature length scale of the background; these frequencies are independent of radius (and hence angular momentum) of the brane itself. This implies that the holographic dual theory must have, in a given R charge sector, low-lying non-BPS excitations with level spacings independent of the R charge.

Sumit R. Das; Antal Jevicki; Samir D. Mathur

2000-12-21T23:59:59.000Z

266

Fundamental oscillation modes of neutron stars: validity of universal relations  

E-Print Network (OSTI)

We study the $f$-mode frequencies and damping times of nonrotating neutron stars (NS) in general relativity (GR) by solving the linearized perturbation equations, with the aim to establish "universal" relations that depend only weakly on the equations of state (EOS). Using a more comprehensive set of EOSs, we re-examine some proposed linearizations that describe the $f$-mode parameters in terms of mass and radius of the neutron star (NS), and we test a more recent proposal for expressing the $f$-mode parameters as quadratic functions of the effective compactness. Our extensive results for each equation of state considered allow us to study the accuracy of each proposal. In particular, we find that the damping time deviates quite considerably from the proposed linearization. We introduce a new universal relation for the product of the $f$-mode frequency and damping time as a function of the (ordinary) compactness, which proved to be more accurate. The relations using the effective compactness on the other hand...

Chirenti, Cecilia; Kastaun, Wolfgang

2015-01-01T23:59:59.000Z

267

Heat pulse propagation studies in TFTR  

SciTech Connect

The time scales for sawtooth repetition and heat pulse propagation are much longer (10's of msec) in the large tokamak TFTR than in previous, smaller tokamaks. This extended time scale coupled with more detailed diagnostics has led us to revisit the analysis of the heat pulse propagation as a method to determine the electron heat diffusivity, chi/sub e/, in the plasma. A combination of analytic and computer solutions of the electron heat diffusion equation are used to clarify previous work and develop new methods for determining chi/sub e/. Direct comparison of the predicted heat pulses with soft x-ray and ECE data indicates that the space-time evolution is diffusive. However, the chi/sub e/ determined from heat pulse propagation usually exceeds that determined from background plasma power balance considerations by a factor ranging from 2 to 10. Some hypotheses for resolving this discrepancy are discussed. 11 refs., 19 figs., 1 tab.

Fredrickson, E.D.; Callen, J.D.; Colchin, R.J.; Efthimion, P.C.; Hill, K.W.; Izzo, R.; Mikkelsen, D.R.; Monticello, D.A.; McGuire, K.; Bell, J.D.

1986-02-01T23:59:59.000Z

268

Optimal arbitrarily accurate composite pulse sequences  

E-Print Network (OSTI)

Implementing a single-qubit unitary is often hampered by imperfect control. Systematic amplitude errors ?, caused by incorrect duration or strength of a pulse, are an especially common problem. But a sequence of imperfect ...

Low, Guang Hao

269

Ultrasonic unipolar pulse/echo instrument  

DOE Patents (OSTI)

An ultrasonic unipolar pulse/echo instrument uses active switches and a timing and drive circuitry to control electrical energy to a transducer, the discharging of the transducer, and the opening of an electrical pathway to the receiving circuitry for the returning echoes. The active switches utilize MOSFET devices along with decoupling circuitry to insure the preservation of the unipolar nature of the pulses, insure fast transition times, and maintain broad band width and time resolution. A housing contains the various circuitry and switches and allows connection to a power supply and a movable ultrasonic transducer. The circuitry maintains low impedance input to the transducer during transmitting cycles, and high impedance between the transducer and the receiving circuit during receive cycles to maintain the unipolar pulse shape. A unipolar pulse is valuable for nondestructive evaluation, a prime use for the present instrument.

Hughes, M.J.; Hsu, D.K.; Thompson, D.O.; Wormley, S.J.

1993-04-06T23:59:59.000Z

270

First gaseous boronization during pulsed discharge cleaning  

NLE Websites -- All DOE Office Websites (Extended Search)

6 2 keV, and a pulse length of 60 ms. The vertical equilibrium field is provided by the image currents inside the 50 mm thick, high-conductivity aluminum (6061-T6) vacuum vessel...

271

The ESRF Miniature Pulsed Magnetic Field System  

SciTech Connect

We have developed a portable system to provide pulsed magnetic fields on the ESRF X-ray beamlines. The complete system consists of a power supply, liquid Helium and liquid Nitrogen dewars with a siphon each, control electronics and a double cryostat for separate coil and sample cooling. The liquid nitrogen cooled solenoids reach a maximum field of 30 Tesla for a total pulse duration of one milisecond. They are constructed for optimised cooling rate after the pulse to obtain a high duty cycle, the repetition rate is five pulses per minute at maximum field. The sample is cooled in an independent Helium flow cryostat which is inserted into the bore of the magnet. The flow cryostat has a temperature range from 5 to 250 Kelvin with a direct contact between the sample and Helium flow. This overview gives a general presentation of the system and we will show recent results.

Linden, Peter J. E. M. van der; Strohm, Cornelius; Roth, Thomas; Detlefs, Carsten; Mathon, Olivier [ESRF, 6 rue Jules Horowitz, F-38043 Grenoble (France)

2010-06-23T23:59:59.000Z

272

MagLab - Pulsed Field Program  

NLE Websites -- All DOE Office Websites (Extended Search)

research: magneto-optics (IR through UV), magnetization and magneto-transport from 350 mK to 300K; GHz conductivity, MHz conductivity, pulse echo ultra-sound spectroscopy,...

273

Pulse Pressure Forming of Lightweight Materials, Development...  

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

Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. lm015smith2010o.pdf More Documents & Publications Pulse-Pressure Forming of Lightweight Metals...

274

Theory of Bernstein modes in graphene  

Science Journals Connector (OSTI)

We present a theoretical description of Bernstein modes that arise as a result of the coupling between plasmonlike collective excitations (upper-hybrid mode) and inter-Landau-level excitations, in graphene in a perpendicular magnetic field. These modes, which are apparent as avoided level crossings in the spectral function obtained in the random-phase approximation, are described to great accuracy in a phenomenological model. Bernstein modes, which may be measured in inelastic light-scattering experiments or in photoconductivity spectroscopy, are a manifestation of the Coulomb interaction between the electrons and may be used for a high-precision measurement of the upper-hybrid mode at small nonzero wave vectors.

R. Roldn; M. O. Goerbig; J.-N. Fuchs

2011-05-17T23:59:59.000Z

275

Electromagnetic or other directed energy pulse launcher  

DOE Patents (OSTI)

The physical realization of new solutions of wave propagation equations, such as Maxwell's equations and the scaler wave equation, produces localized pulses of wave energy such as electromagnetic or acoustic energy which propagate over long distances without divergence. The pulses are produced by driving each element of an array of radiating sources with a particular drive function so that the resultant localized packet of energy closely approximates the exact solutions and behaves the same.

Ziolkowski, Richard W. (Livermore, CA)

1990-01-01T23:59:59.000Z

276

Multiple laser pulse ignition method and apparatus  

DOE Patents (OSTI)

Two or more laser light pulses with certain differing temporal lengths and peak pulse powers can be employed sequentially to regulate the rate and duration of laser energy delivery to fuel mixtures, thereby improving fuel ignition performance over a wide range of fuel parameters such as fuel/oxidizer ratios, fuel droplet size, number density and velocity within a fuel aerosol, and initial fuel temperatures. 18 figs.

Early, J.W.

1998-05-26T23:59:59.000Z

277

Multiple laser pulse ignition method and apparatus  

DOE Patents (OSTI)

Two or more laser light pulses with certain differing temporal lengths and peak pulse powers can be employed sequentially to regulate the rate and duration of laser energy delivery to fuel mixtures, thereby improving fuel ignition performance over a wide range of fuel parameters such as fuel/oxidizer ratios, fuel droplet size, number density and velocity within a fuel aerosol, and initial fuel temperatures.

Early, James W. (Los Alamos, NM)

1998-01-01T23:59:59.000Z

278

Pulse width modulation inverter with battery charger  

DOE Patents (OSTI)

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

Slicker, James M. (Union Lake, MI)

1985-01-01T23:59:59.000Z

279

Concentration Distributions during Pulse Jet Mixing  

SciTech Connect

Obtaining real-time, in situ slurry concentration measurements during unsteady mixing can provide increased understanding into mixer performance. During recent tests an ultrasonic attenuation sensor was inserted into a mixing vessel to measure the slurry concentration during unsteady mixing in real time during pulse jet mixer operation. These pulse jet mixing tests to suspend noncohesive solids in Newtonian liquid were conducted at three geometric scales. To understand the solids suspension process and resulting solids distribution, the concentration of solids in the cloud was measured at various elevations and radial positions during the pulse jet mixer cycle. In the largest scale vessel, concentration profiles were measured at three radial locations: r = 0, 0.5 and 0.9 R where R is the vessel radius. These radial concentration data are being analyzed to provide a model for predicting concentration as a function of elevation. This paper describes pulse jet mixer operation, provides a description of the concentration probe, and presents transient concentration data obtained at three radial positions: in the vessel center (O R), midway between the center and the wall (0.5 R) and near the vessel wall (0.9 R) through out the pulse to provide insight into pulse jet mixer performance.

Bamberger, Judith A.; Meyer, Perry A.

2010-08-05T23:59:59.000Z

280

Glossary Term - Neptune  

NLE Websites -- All DOE Office Websites (Extended Search)

Mole Mole Previous Term (Mole) Glossary Main Index Next Term (Neutrino) Neutrino Neptune Neptune as seen by the Voyager II spacecraft on August 14, 1989. Neptune is the eighth planet from the sun and takes 165 years to orbit the sun once. Neptune is about 4 times larger than the Earth and is about 17 times as massive. Neptune was discovered on September 23, 1846 based on calculations done by the French astronomer Urbain LeVerrier and the English astronomer John Adams. Neptune is also the Roman name for Poseidon, the god of the sea and earthquakes. Neptune was the son of Chronus and Rhea and carries the trident, a three pronged spear. Planetary Data Distance from Sun Length of Day Length of Year Radius Mass 30.069 AU 16.1 hours 164.79 years 24,764 km 1.02*1026 kg Known Satellites

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281

Glossary Term - Beta Decay  

NLE Websites -- All DOE Office Websites (Extended Search)

Avogadro's Number Avogadro's Number Previous Term (Avogadro's Number) Glossary Main Index Next Term (Beta Particle) Beta Particle Beta Decay Beta decay results in the emission of an electron and antineutrino, or a positron and neutrino. Beta decay is one process that unstable atoms can use to become more stable. There are two types of beta decay, beta-minus and beta-plus. During beta-minus decay, a neutron in an atom's nucleus turns into a proton, an electron and an antineutrino. The electron and antineutrino fly away from the nucleus, which now has one more proton than it started with. Since an atom gains a proton during beta-minus decay, it changes from one element to another. For example, after undergoing beta-minus decay, an atom of carbon (with 6 protons) becomes an atom of nitrogen (with 7 protons).

282

Glossary Term - Electron Capture  

NLE Websites -- All DOE Office Websites (Extended Search)

Electron Electron Previous Term (Electron) Glossary Main Index Next Term (Electron Volt (eV)) Electron Volt (eV) Electron Capture After electron capture, an atom contains one less proton and one more neutron. Electron capture is one process that unstable atoms can use to become more stable. During electron capture, an electron in an atom's inner shell is drawn into the nucleus where it combines with a proton, forming a neutron and a neutrino. The neutrino is ejected from the atom's nucleus. Since an atom loses a proton during electron capture, it changes from one element to another. For example, after undergoing electron capture, an atom of carbon (with 6 protons) becomes an atom of boron (with 5 protons). Although the numbers of protons and neutrons in an atom's nucleus change

283

Glossary Term - Ceres  

NLE Websites -- All DOE Office Websites (Extended Search)

Catalyst Catalyst Previous Term (Catalyst) Glossary Main Index Next Term (Cloud Chamber) Cloud Chamber Ceres Ceres is an asteroid located between the orbits of Mars and Jupiter. Discovered on January 1, 1801 by Giuseppi Piazzi, Ceres was the first asteroid ever discovered. With a diameter of 1025 kilometers (637 miles), Ceres is also the largest known asteroid. Ceres is also the Roman name for the Greek goddess Demeter, the elder sister of Zeus and daughter of Cronus and Rhea. Demeter was the goddess of grain and helped the crops grow. One day her daughter, Persephone, was abducted by Hades. While Demeter searched for her missing daughter, no crops grew and people starved. Persephone was eventually found, but Hades refused to let her leave the underworld. As a compromise, Persephone is

284

Long Term Innovative Technologies  

NLE Websites -- All DOE Office Websites (Extended Search)

DOE's Hydrogen and DOE's Hydrogen and Fuel Cell Technologies, Fuel Cell Presolicitation Workshop Bryan Pivovar With Input/Feedback from Rod Borup (LANL), Debbie Myers (ANL), DOE and others as noted in presentation Lakewood, CO March 16, 2010 Long Term Innovative Technologies National Renewable Energy Laboratory Innovation for Our Energy Future Innovative/Long Term and RELEVANT Mission of DOE Mission of EERE (Applied Program) Mission of HFCT To enable the widespread commercialization of hydrogen and fuel cells in diverse sectors of the economy-with emphasis on applications that will most effectively strengthen the nation's energy security and improve our stewardship of the environment-through research, development, and demonstration of critical improvements in the technologies, and through diverse activities to overcome

285

Glossary Term - Uranus  

NLE Websites -- All DOE Office Websites (Extended Search)

Tritium Tritium Previous Term (Tritium) Glossary Main Index Next Term (Van de Graaff Generator) Van de Graaff Generator Uranus Uranus as seen by the Voyager II spacecraft. Uranus is the seventh planet from the sun and takes 84 years to orbit the sun once. Uranus is about 4 times larger than the Earth and is about 14.5 times as massive. Uranus was discovered on March 13, 1781 by William Herschel. In greek mythology, Uranus was Father Sky. Planetary Data Distance from Sun Length of Day Length of Year Radius Mass 19.191 AU 17.2 hours 84.01 years 25,559 km 8.68*1025 kg Known Satellites Name Distance from Uranus Rotational Period Orbital Period Radius Cordelia 49,770 km -unknown- 0.335034 days 21 km Ophelia 53,790 km -unknown- 0.376400 days 23 km Bianca 59,170 km -unknown- 0.434579 days 27 km

286

Efficient Cherenkov emission of broadband terahertz radiation from an ultrashort laser pulse in a sandwich structure with nonlinear core  

SciTech Connect

A scheme for efficient generation of broadband terahertz radiation by a femtosecond laser pulse propagating in a planar sandwichlike structure is proposed. The structure consists of a thin nonlinear core cladded with prisms made of a material with low terahertz absorption. The focused into a line laser pulse propagates in the core as a leaky or waveguide mode and emits Cherenkov wedge of terahertz waves in the cladding. We developed a theory that describes terahertz generation in such a structure and calculated spatial distribution of the generated terahertz field, its energy spectrum and optical-to-terahertz conversion efficiency. The developed theory predicts the conversion efficiency of up to several percent in a 1 cm long and 1 cm wide Si-LiNbO{sub 3}-Si sandwich structure with a 20 {mu}m thick nonlinear layer pumped by 8.5 {mu}J Ti:sapphire laser with pulse duration of 100 fs.

Bodrov, S. B. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); University of Nizhny Novgorod, Nizhny Novgorod 603950 (Russian Federation); Bakunov, M. I. [University of Nizhny Novgorod, Nizhny Novgorod 603950 (Russian Federation); Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Hangyo, M. [Laser Terahertz Division, Institute of Laser Engineering, Osaka University, Osaka (Japan)

2008-11-01T23:59:59.000Z

287

Stretching dependence of the vibration modes of a single-molecule Pt-H2-Pt bridge  

Science Journals Connector (OSTI)

A conducting bridge of a single hydrogen molecule between Pt electrodes is formed in a break junction experiment. It has a conductance near the quantum unit, G0=2e2?h, carried by a single channel. Using point-contact spectroscopy three vibration modes are observed and their variation upon isotope substitution is obtained. The stretching dependence for each of the modes allows uniquely classifying them as longitudinal or transversal modes. The interpretation of the experiment in terms of a Pt-H2-Pt bridge is verified by density-functional theory calculations for the stability, vibrational modes, and conductance of the structure.

D. Djukic; K. S. Thygesen; C. Untiedt; R. H. M. Smit; K. W. Jacobsen; J. M. van Ruitenbeek

2005-04-20T23:59:59.000Z

288

A Summary of Taxonomies of Digital System Failure Modes Provided by the DigRel Task Group  

SciTech Connect

Recently, the CSNI directed WGRisk to set up a task group called DIGREL to initiate a new task on developing a taxonomy of failure modes of digital components for the purposes of PSA. It is an important step towards standardized digital I&C reliability assessment techniques for PSA. The objective of this paper is to provide a comparison of the failure mode taxonomies provided by the participants. The failure modes are classified in terms of their levels of detail. Software and hardware failure modes are discussed separately.

Chu T. L.; Yue M.; Postma, W.

2012-06-25T23:59:59.000Z

289

Experimental characterization of a self-filtering unstable resonator applied to a short pulse XeCl laser  

SciTech Connect

A self-filtering unstable resonator with magnification ZMZ = 5 has beenapplied to a pulsed UV-preionized XeCl excimer laser. In agreement withnumerical results it is experimentally shown that less than two cavity roundtrips are needed to establish a steady state lowest-order mode. Adiffraction-limited laser beam with a brightness of 1.5 /times/ 10/sup 13/ Wcm/sup /minus/2/ Sr/sup /minus/1/ has been obtained.

Luches, A.; Nassisi, V.; Perrone, M. R.

1989-06-01T23:59:59.000Z

290

Inter-individual difference of one type of pulsed sounds produced by beluga whales (Delphinapterus leucas)  

Science Journals Connector (OSTI)

Belugas often exchange one type of broadband pulsed sounds (termed PS1 calls) which possibly functions as a contact calls (Morisaka et al. 2013). Here we investigate how belugas embed their signature information into the PS1 calls. PS1 calls were recorded from each of five belugas including both sexes and various ages at the Port of Nagoya Public Aquarium using a broadband recording system when in isolation. Temporal and spectral acoustic parameters of PS1 calls were measured and compared among individuals. Kruskal-Wallis test revealed that inter-pulse intervals (IPIs) the number of pulses and pulse rates of PS1 calls had significant differences among individuals but duration did not (?2?=?76.7 p<0.0001; ?2?=?26.2 p<0.0001; ?2?=?45.3 p<0.0001; and ?2?=?4.7 p?=?0.316 respectively). The contours depicted by the IPIs as a function of pulse order were also individually different and only the contours of a calf fluctuated over time. Four belugas except a juvenile had individually distinctive power spectra. These results suggest that several acoustic parameters of PS1 calls may hold individual information. We found PS1-like calls from the other captive belugas (Yokohama Hakkeijima Sea Paradise) suggested that the PS1 call is not the specific call for one captive population but the basic call type for belugas.

2014-01-01T23:59:59.000Z

291

Two-pulse driving of D + D nuclear fusion within a single Coulomb exploding nanodroplet  

Science Journals Connector (OSTI)

This paper presents a computational study of D + D fusion driven by Coulomb explosion (CE) within a single homonuclear deuterium nanodroplet subjected to double-pulse ultraintense laser irradiation. This irradiation scheme results in the attainment (by the first weaker pulse) of a transient inhomogeneous density profile which serves as a target for the driving (by the second superintense pulse) of nonuniform CE that triggers overrun effects and induces intrananodroplet (INTRA) D + D fusion. Scaled electron and ion dynamics simulations were utilized to explore the INTRA D + D fusion yields for double-pulse near-infrared laser irradiation of deuterium nanodroplets. The dependence of the INTRA yield on the nanodroplet size and on the parameters of the two laser pulses was determined establishing the conditions for the prevalence of efficient INTRA fusion. The INTRA fusion yields are amenable to experimental observation within an assembly of nanodroplets. The INTRA D + D fusion can be distinguished from the concurrent internanodroplet D + D fusion reaction occurring in the macroscopic plasma filament and outside it in terms of the different energies of the neutrons produced in these two channels.

Isidore Last; Fabio Peano; Joshua Jortner; Luis O. Silva

2010-01-01T23:59:59.000Z

292

2342 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 39, NO. 12, DECEMBER 2004 A 4-A Quiescent-Current Dual-Mode Digitally  

E-Print Network (OSTI)

2342 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 39, NO. 12, DECEMBER 2004 A 4-A Quiescent voltage compatibility between a single-cell lithium-ion battery voltage and a low-voltage integrated with each full charge of the battery, pulse frequency modulation (PFM) mode is preferred for light load

Sanders, Seth

293

Representation of Ideal Magnetohydrodynamic Modes  

SciTech Connect

One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through ? ? = ? X (xi X B) ensures that ? B ? ? = 0 at a resonance, with ? labelling an equilibrium flux surface. Also useful for the analysis of guiding center orbits in a perturbed field is the representation ? ? = ? X ?B. These two representations are equivalent, but the vanishing of ? B ?? at a resonance is necessary but not sufficient for the preservation of field line topology, and a indiscriminate use of either perturbation in fact destroys the original equilibrium flux topology. It is necessary to find the perturbed field to all orders in xi to conserve the original topology. The effect of using linearized perturbations on stability and growth rate calculations is discussed

Roscoe B. White

2013-01-15T23:59:59.000Z

294

Laser triggering of water switches in terrawatt-class pulse power accelerators.  

SciTech Connect

Focused Beams from high-power lasers have been used to command trigger gas switches in pulse power accelerators for more than two decades. This Laboratory-Directed Research and Development project was aimed at determining whether high power lasers could also command trigger water switches on high-power accelerators. In initial work, we determined that focused light from three harmonics of a small pulsed Nd:YAG laser at 1064 nm, 532 nm, and 355 nm could be used to form breakdown arcs in water, with the lowest breakdown thresholds of 110 J/cm{sup 2} or 14 GW/cm{sup 2} at 532 nm in the green. In laboratory-scale laser triggering experiments with a 170-kV pulse-charged water switch with a 3-mm anode-cathode gap, we demonstrated that {approx}90 mJ of green laser energy could trigger the gap with a 1-{sigma} jitter of less than 2ns, a factor of 10 improvement over the jitter of the switch in its self breaking mode. In the laboratory-scale experiments we developed optical techniques utilizing polarization rotation of a probe laser beam to measure current in switch channels and electric field enhancements near streamer heads. In the final year of the project, we constructed a pulse-power facility to allow us to test laser triggering of water switches from 0.6- MV to 2.0 MV. Triggering experiments on this facility using an axicon lens for focusing the laser and a switch with a 740 kV self-break voltage produced consistent laser triggering with a {+-} 16-ns 1-{sigma} jitter, a significant improvement over the {+-} 24-ns jitter in the self-breaking mode.

Woodworth, Joseph Ray; Johnson, David Lee (Titan Pulse Sciences, San Leandro, CA); Wilkins, Frank (Bechtel Nevada, Las Vegas, NV); Van De Valde, David (EG& G Technical Services, Albuquerque, NM); Sarkisov, Gennady Sergeevich (Ktech Corporation, Albuquerque, NM); Zameroski, Nathan D.; Starbird, Robert L. (Bechtel Nevada, Las Vegas, NV)

2005-12-01T23:59:59.000Z

295

Injection locked oscillator system for pulsed metal vapor lasers  

DOE Patents (OSTI)

An injection locked oscillator system for pulsed metal vapor lasers is disclosed. The invention includes the combination of a seeding oscillator with an injection locked oscillator (ILO) for improving the quality, particularly the intensity, of an output laser beam pulse. The present invention includes means for matching the first seeder laser pulses from the seeding oscillator to second laser pulses of a metal vapor laser to improve the quality, and particularly the intensity, of the output laser beam pulse.

Warner, Bruce E. (Livermore, CA); Ault, Earl R. (Dublin, CA)

1988-01-01T23:59:59.000Z

296

Hydrodynamic Efficiency of Ablation Propulsion with Pulsed Ion Beam  

SciTech Connect

This paper presents the hydrodynamic efficiency of ablation plasma produced by pulsed ion beam on the basis of the ion beam-target interaction. We used a one-dimensional hydrodynamic fluid compressible to study the physics involved namely an ablation acceleration behavior and analyzed it as a rocketlike model in order to investigate its hydrodynamic variables for propulsion applications. These variables were estimated by the concept of ablation driven implosion in terms of ablated mass fraction, implosion efficiency, and hydrodynamic energy conversion. Herein, the energy conversion efficiency of 17.5% was achieved. In addition, the results show maximum energy efficiency of the ablation process (ablation efficiency) of 67% meaning the efficiency with which pulsed ion beam energy-ablation plasma conversion. The effects of ion beam energy deposition depth to hydrodynamic efficiency were briefly discussed. Further, an evaluation of propulsive force with high specific impulse of 4000s, total impulse of 34mN and momentum to energy ratio in the range of {mu}N/W was also analyzed.

Buttapeng, Chainarong; Yazawa, Masaru; Harada, Nobuhiro [Department of Electrical Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan); Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi [Extreme Energy-Density Research Institute, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan)

2006-05-02T23:59:59.000Z

297

CVD Diamond Detectors for Current Mode Neutron Time-of-Flight Spectroscopy at OMEGA/NIF  

SciTech Connect

We have performed pulsed neutron and pulsed laser tests of a CVD diamond detector manufactured from DIAFILM, a commercial grade of CVD diamond. The laser tests were performed at the short pulse UV laser at Bechtel Nevada in Livermore, CA. The pulsed neutrons were provided by DT capsule implosions at the OMEGA laser fusion facility in Rochester, NY. From these tests, we have determined the impulse response to be 250 ps fwhm for an applied E-field of 500 V/mm. Additionally, we have determined the sensitivity to be 2.4 mA/W at 500 V/mm and 4.0 mA/W at 1000 V/mm. These values are approximately 2 to 5x times higher than those reported for natural Type IIa diamond at similar E-field and thickness (1mm). These characteristics allow us to conceive of a neutron time-of-flight current mode spectrometer based on CVD diamond. Such an instrument would sit inside the laser fusion target chamber close to target chamber center (TCC), and would record neutron spectra fast enough such that backscattered neutrons and x-rays from the target chamber wall would not be a concern. The acquired neutron spectra could then be used to extract DD fuel areal density from the downscattered secondary to secondary ratio.

G. J. Schmid; V. Yu. Glebov; A. V. Friensehner; D. R. Hargrove; S. P. Hatchett; N. Izumi; R. A. Lerche; T. W. Phillips; T. C. Sangster; C. Silbernagel; C. Stoecki

2001-07-01T23:59:59.000Z

298

Seismic pulse propagation with constant Q and stable probability distributions  

E-Print Network (OSTI)

The one-dimensional propagation of seismic waves with constant Q is shown to be governed by an evolution equation of fractional order in time, which interpolates the heat equation and the wave equation. The fundamental solutions for the Cauchy and Signalling problems are expressed in terms of entire functions (of Wright type) in the similarity variable and their behaviours turn out to be intermediate between those for the limiting cases of a perfectly viscous fluid and a perfectly elastic solid. In view of the small dissipation exhibited by the seismic pulses, the nearly elastic limit is considered. Furthermore, the fundamental solutions for the Cauchy and Signalling problems are shown to be related to stable probability distributions with index of stability determined by the order of the fractional time derivative in the evolution equation.

Francesco Mainardi; Massimo Tomirotti

2010-08-07T23:59:59.000Z

299

Flu Terms Defined  

NLE Websites -- All DOE Office Websites (Extended Search)

Flu Terms Defined Flu Terms Defined H1N1 Influenza is a respiratory disease of pigs caused by type A influenza viruses that causes regular outbreaks in pigs. People do not normally get H1N1 flu, but human infections can and do happen. H1N1 flu viruses have been reported to spread from person-to-person, but in the past, this transmission was limited and not sustained beyond three people. Avian flu (AI) is caused by influenza viruses that occur naturally among wild birds. Low pathogenic AI is common in birds and causes few problems. Highly pathogenic H5N1 is deadly to domestic fowl, can be transmitted from birds to humans, and is deadly to humans. There is virtually no human immunity and human vaccine availability is very limited. Pandemic flu is virulent human flu that causes a global outbreak, or pandemic, of serious illness. Because there is little natural immunity, the disease can spread easily from person to person. Currently, there is no pandemic flu.

300

Generation of a beam of fast electrons by tightly focusing a radially polarized ultrashort laser pulse  

SciTech Connect

The generation of an electron beam through longitudinal field acceleration from a tightly focused radially polarized (TM{sub 01}) laser mode is reported. The longitudinal field is generated by focusing a TM{sub 01} few-cycle laser pulse (1.8 {mu}m, 550 {mu}J, 15 fs) with a high numerical aperture parabola. The created longitudinal field in the focal region is intense enough to ionize atoms and accelerate electrons to 23 keV of energy from a low density oxygen gas. The characteristics of the electron beam are presented.

Payeur, S.; Fourmaux, S.; Schmidt, B. E.; MacLean, J. P.; Tchervenkov, C.; Legare, F.; Kieffer, J. C. [ALLS Facility, Institut National de la Recherche Scientifique Energie, Materiaux et Telecommunications (INRS-EMT), 1650, boul. Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada); Piche, M. [Centre d'Optique, Photonique et Laser (COPL), 2375 rue de la Terrasse, Universite Laval, Quebec G1V 0A6 (Canada)

2012-07-23T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Pulsed electrospark deposition of MAX phase Cr2AlC based coatings on titanium alloy  

Science Journals Connector (OSTI)

Abstract Coatings with a high amount of MAX phase were obtained onto Ti substrate using the pulsed electrospark deposition (PED) technique and Cr2AlC electrode material (??). The structure and phase formation of the coatings generated at different modes were studied. It was found, that a layer of titanium carbide was formed during the initial stage of the deposition at the interface as a result of chemical reaction between Cr2AlC electrode and Ti substrate which further acts as a diffusion barrier.

E.I. Zamulaeva; E.A. Levashov; T.A. Sviridova; N.V. Shvyndina; M.I. Petrzhik

2013-01-01T23:59:59.000Z

302

Thyristor stack for pulsed inductive plasma generation  

SciTech Connect

A thyristor stack for pulsed inductive plasma generation has been developed and tested. The stack design includes a free wheeling diode assembly for current reversal. Triggering of the device is achieved by a high side biased, self supplied gate driver unit using gating energy derived from a local snubber network. The structure guarantees a hard firing gate pulse for the required high dI/dt application. A single fiber optic command is needed to achieve a simultaneous turn on of the thyristors. The stack assembly is used for switching a series resonant circuit with a ringing frequency of 30 kHz. In the prototype pulsed power system described here an inductive discharge has been generated with a pulse duration of 120 {mu}s and a pulse energy of 50 J. A maximum power transfer efficiency of 84% and a peak power of 480 kW inside the discharge were achieved. System tests were performed with a purely inductive load and an inductively generated plasma acting as a load through transformer action at a voltage level of 4.1 kV, a peak current of 5 kA, and a current switching rate of 1 kA/{mu}s.

Teske, C.; Jacoby, J.; Schweizer, W.; Wiechula, J. [Plasmaphysics Group, Institute of Applied Physics, Johann-Wolfgang-Goethe University, 60438 Frankfurt am Main (Germany)

2009-03-15T23:59:59.000Z

303

Three-dimensional photodissociation in strong laser fields: Memory-kernel effective-mode expansion  

SciTech Connect

We introduce a method for the efficient computation of non-Markovian quantum dynamics for strong (and time-dependent) system-bath interactions. The past history of the system dynamics is incorporated by expanding the memory kernel in exponential functions thereby transforming in an exact fashion the non-Markovian integrodifferential equations into a (larger) set of ''effective modes'' differential equations (EMDE). We have devised a method which easily diagonalizes the EMDE, thereby allowing for the efficient construction of an adiabatic basis and the fast propagation of the EMDE in time. We have applied this method to three-dimensional photodissociation of the H{sub 2}{sup +} molecule by strong laser fields. Our calculations properly include resonance-Raman scattering via the continuum, resulting in extensive rotational and vibrational excitations. The calculated final kinetic and angular distribution of the photofragments are in overall excellent agreement with experiments, both when transform-limited pulses and when chirped pulses are used.

Li Xuan [Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3 (Canada); Thanopulos, Ioannis [Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Athens 11635 (Greece); Shapiro, Moshe [Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3 (Canada); Department of Chemical Physics, Weizmann Institute, Rehovot 76100 (Israel)

2011-03-15T23:59:59.000Z

304

Graphene sustained nonlinear modes in dielectric waveguides  

Science Journals Connector (OSTI)

We discuss the existence of nonlinear modes sustained by graphene layers in dielectric waveguides. Taking advantage of the almost two dimensional nature of graphene, we introduce the...

Auditore, Aldo; De Angelis, Costantino; Locatelli, Andrea; Boscolo, Stefano; Midrio, Michele; Romagnoli, Marco; Capobianco, Antonio-Daniele; Nalesso, Gianfranco

2013-01-01T23:59:59.000Z

305

FMEA (Failure Mode and Effects Analysis)  

Science Journals Connector (OSTI)

FMEA (Failure Mode and Effects Analysis; Fehlermglichkeits- und Einflussanalyse) als universelles Methodenmodell folgt dem Grundgedanken einer prventiven Fehlervermeidung anstelle einer nachsorgenden Fehler...

A. Gbel

2014-01-01T23:59:59.000Z

306

Pulse shaping effects on weld porosity in laser beam spot welds : contrast of long- & short- pulse welds.  

SciTech Connect

Weld porosity is being investigated for long-pulse spot welds produced by high power continuous output lasers. Short-pulse spot welds (made with a pulsed laser system) are also being studied but to a much small extent. Given that weld area of a spot weld is commensurate with weld strength, the loss of weld area due to an undefined or unexpected pore results in undefined or unexpected loss in strength. For this reason, a better understanding of spot weld porosity is sought. Long-pulse spot welds are defined and limited by the slow shutter speed of most high output power continuous lasers. Continuous lasers typically ramp up to a simmer power before reaching the high power needed to produce the desired weld. A post-pulse ramp down time is usually present as well. The result is a pulse length tenths of a second long as oppose to the typical millisecond regime of the short-pulse pulsed laser. This study will employ a Lumonics JK802 Nd:YAG laser with Super Modulation pulse shaping capability and a Lasag SLS C16 40 W pulsed Nd:YAG laser. Pulse shaping will include square wave modulation of various peak powers for long-pulse welds and square (or top hat) and constant ramp down pulses for short-pulse welds. Characterization of weld porosity will be performed for both pulse welding methods.

Ellison, Chad M. (Honeywell FM& T, Kansas City, MO); Perricone, Matthew J. (R.J. Lee Group, Inc., Monroeville, PA); Faraone, Kevin M. (BWX Technologies, Inc., Lynchburg, VA); Norris, Jerome T.

2007-10-01T23:59:59.000Z

307

ARE PULSING SOLITARY WAVES RUNNING INSIDE THE SUN?  

SciTech Connect

A precise sequence of frequencies-detected four independent ways-is interpreted as a system of solitary waves below the Sun's convective envelope. Six future observational or theoretical tests of this idea are suggested. Wave properties (rotation rates, radial energy distribution, nuclear excitation strength) follow from conventional dynamics of global oscillation modes after assuming a localized nuclear term strong enough to perturb and hold mode longitudes into alignments that form 'families'. To facilitate future tests, more details are derived for a system of two dozen solitary waves 2 {<=} l {<=} 25. Wave excitation by {sup 3}He and {sup 14}C burning is complex. It spikes by factors M{sub 1} {<=} 10{sup 3} when many waves overlap in longitude but its long-time average is M{sub 2} {<=} 10. Including mixing can raise overall excitation to {approx}50 times that in a standard solar model. These spikes cause tiny phase shifts that tend to pull wave rotation rates toward their ideal values {proportional_to}[l(l + 1)]{sup -1}. A system like this would generate some extra nuclear energy in two spots at low latitude on opposite sides of the Sun. Each covers about 20 Degree-Sign of longitude. Above a certain wave amplitude, the system starts giving distinctly more nuclear excitation to some waves (e.g., l = 9, 14, and 20) than to neighboring l values. The prominence of l = 20 has already been reported. This transition begins at temperature amplitudes {Delta}T/T = 0.03 in the solar core for a typical family of modes, which corresponds to {delta}T/T {approx} 0.001 for one of its many component oscillation modes.

Wolff, Charles L., E-mail: charles.l.wolff@nasa.gov [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2012-09-10T23:59:59.000Z

308

Thermal performance testing of two Thales 9310 pulse-tube cryocoolers for PHyTIR  

SciTech Connect

PHyTIR is a NASA-funded technology demonstration for a near-term earth-observing instrument in the thermal infrared spectrum, intended for use in the HyspIRI mission. PHyTIR will use two Thales 9310 single-stage pulse tube cryocoolers, one to directly cool the FPA, the other to simulate a passive radiator. We report performance measurements for the two Thales 9310 cryocoolers intended for inclusion in the PHyTIR demonstrator.

Paine, Christopher G. [Jet Propulsion Laboratory, California Institute of Technology 4800 Oak Grove Drive, Pasadena CA 91109 (United States)

2014-01-29T23:59:59.000Z

309

Multipacting saturation in parallel plate and micro-pulse electron gun  

E-Print Network (OSTI)

A novel parallel plate model is proposed that divided the electron cloud into three parts at saturation, and it is studied in detail using both an analytical approach and PIC (Particle In Cell) code simulations. As one part of the electron cloud, ribbons modes are suggested by tracking the trajectory of individual particle, and the aim of this mode form is to simplify the progress of multipacting effect in the parallel plate so as to be eliminated by optimizing RF parameters. The micro-pulse electron gun (MPG) has demonstrated the potential to address the need for high peak and average current electron beams, hence studying the multipacting in MPG is essential. On the basis of multipacting studying in the parallel plate, it is clear that increasing the cavity voltage is of interest in yielding high quality beams in the gun.

Liao, Lang; Zhao, Minghua

2014-01-01T23:59:59.000Z

310

Initial Structure and Growth Dynamics of YBa2Cu3O7-? during Pulsed Laser Deposition  

Science Journals Connector (OSTI)

The initial heteroepitaxial growth of YBa2Cu3O7-? films on SrTiO3(001) substrates during pulsed laser deposition shows a growth-mode transition and a change of growth unit. The growth starts with two blocks, each two-thirds the size of the complete unit cell. The first of these blocks grows in a step-flow fashion, whereas the second grows in the layer-by-layer mode. Subsequent deposition occurs layer-by-layer of complete unit cells. These results suggest that the surface diffusion in the heteroepitaxial case is strongly influenced by the competition with formation energies, which is important for the fabrication of heteroepitaxial devices on the unit cell scale.

V. Vonk; K. J. I. Driessen; M. Huijben; G. Rijnders; D. H. A. Blank; H. Rogalla; S. Harkema; H. Graafsma

2007-11-09T23:59:59.000Z

311

Pulsed-laser-excited Raman spectra of shock-compressed triaminotrinitrobenzene  

SciTech Connect

Pulsed-laser-excited Raman scattering methods have been used to examine sustained shock compression of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) at an optical window interface. Records of vibrational frequency shifts and line shape changes have been obtained under variable and well-controlled shock loading using a 63-mm-diameter compressed gas gun to provide a planar impact geometry. To facilitate interpretation of the shock data. Raman spectra of TATB samples at elevated temperatures and ambient pressure have also been acquired. Raman modes identified with the nitro and amino groups in TATB exhibit complex behavior arising from interactions associated with the extensive intra- and intermolecular hydrogen bonding network in this material. The distinct (and frequently competing) effects of pressure and temperature on these modes are discussed in relation to the known insensitivity of TATB to shock initiation. 20 refs., 9 figs.

Trott, W.M.; Renlund, A.M. (Sandia National Labs., Albuquerque, NM (USA))

1989-01-01T23:59:59.000Z

312

Role of laser pre-pulse wavelength and inter-pulse delay on signal enhancement in collinear double-pulse laser-induced  

E-Print Network (OSTI)

used in laser-produced plasma (LPP) for x-ray [20,21] and EUV emission enhancement [22,23]. The DP applications in the fields of microscopy, lithography and x-ray laser. Compared to single-pulse LIBS, DPLIBSRole of laser pre-pulse wavelength and inter-pulse delay on signal enhancement in collinear double

Harilal, S. S.

313

Long-Term Risk From Actinides in the Environment: Modes of Mobility  

SciTech Connect

Laboratory soil column experiments were conducted to investigate the migration of plutonium in soils from the Waste Isolation Pilot Plant (WIPP) and the Rocky Flats Environmental Technology Site.

Shawki Ibrahim, Ph.D.

2001-05-24T23:59:59.000Z

314

Preliminary design of atlas pulsed power machine. Final report  

SciTech Connect

During the contract period from March 95 to March 96 I participated in the preliminary design of the Atlas pulsed power machine. As part of this task I performed of the order of 1000 circuit simulations for many different bank configurations, opening switches, and loads, and about 100 electrostatic field calculations. Results of the calculations were provided at regular Atlas design meetings or in the form of memorandums. I have almost completed the development of a 2D disk transmission line code to more accurately calculate asymmetric transient current and voltage caused by azimuthal variations, including switch timing jitter and local arc faults. This code is attached as a subroutine to the circuit simulation program. The purpose for most of the simulations was to provide information on bank damping requirements and load energy ranges for the different circuit configurations. A minimum transmission line insulation depth was determined from calculating the maximum expected dynamic load back voltage (I{times}{sup dL}/{sub dt}). Other simulations included fault effects, transmission line heating effects (including diffusion, melting, vaporization, ionization), and transmission line transients under various conditions. The line fault simulations using a lumped constant approximation to the 2D disk line provided useful information but even with about 600 elements, it has an upper limit on mode frequencies and tends to exaggerate some modes. Electrostatic (2D) field calculations were used to estimate fields of the transmission lines, insulators, and rail gap switches. Design of conductor surface contours to minimize the field near an insulator stack was one result of these calculations. Effects of biasing and insulator modifications of the rail gap switch was determined.

Gribble, R.F.

1996-04-03T23:59:59.000Z

315

A Self-Biasing Pulsed Depressed Collector  

SciTech Connect

Depressed collectors have been utilized successfully for many years to improve the electrical efficiency of vacuum electron devices. Increasingly, pulsed, high-peak power accelerator applications are placing a premium on electrical efficiency. As RF systems are responsible for a large percentage of the overall energy usage at accelerator laboratories, methods to improve upon the state-of-the-art in pulsed high-power sources are desired. This paper presents a technique for self-biasing the stages in a multistage depressed collector. With this technique, the energy lost during the rise and fall times of the pulse can be recovered, separate power supplies are not needed, and existing modulators can be retrofitted. Calculations show that significant cost savings can be realized with the implementation of this device in high-power systems. In this paper, the technique is described along with experimental demonstration. (auth)

Kemp, Mark A.; Jensen, Aaron; Neilson, Jeff; /SLAC

2014-05-29T23:59:59.000Z

316

Pulsed pyroelectric crystal-powered gamma source  

SciTech Connect

A compact pulsed gamma generator is being developed to replace radiological sources used in commercial, industrial and medical applications. Mono-energetic gammas are produced in the 0.4 - 1.0 MeV energy range using nuclear reactions such as {sup 9}Be(d,n{gamma}){sup 10}B. The gamma generator employs an RF-driven inductively coupled plasma ion source to produce deuterium ion current densities up to 2 mA/mm{sup 2} and ampere-level current pulses can be attained by utilizing an array extraction grid. The extracted deuterium ions are accelerated to approximately 300 keV via a compact stacked pyroelectric crystal system and then bombard the beryllium target to generate gammas. The resulting microsecond pulse of gammas is equivalent to a radiological source with curie-level activity.

Chen, A. X.; Antolak, A. J.; Leung, K.-N.; Raber, T. N.; Morse, D. H. [Sandia National Laboratories, Livermore, CA 94550 (United States)

2013-04-19T23:59:59.000Z

317

Independent Component Analysis Applied to Pulse Oximetry in the Estimation of the Arterial Oxygen Saturation (SpO2)  

E-Print Network (OSTI)

and construction of small, discrete, and low-power pulse oximeter devices. 2) Digital signal processing of discreteness and long-term compat- ibility, and battery powered Light Emitting Diodes (LEDs). 3) Integration of these new technologies which typically features telehealth solutions into the established health care system

318

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Tailored Terahertz Pulses from a Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Wednesday, 29 November 2006 00:00 Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. Interaction of the ALS electron beam with a femtosecond laser pulse as they co-propagate through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration as the laser pulse. This causes a dispersion of the electron trajectories, and the bunch develops a hole that emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. The technique allows tremendous flexibility in shaping the terahertz pulses by appropriate modulation of the laser pulse.

319

Pulsed Laser Deposition of Photoresponsive Two-Dimensional GaSe Nanosheet Networks  

SciTech Connect

Here we explore pulsed laser deposition (PLD), a well known and versatile synthesis method principally used for epitaxial oxide thin film growth, for the synthesis of functional metal chalcogenide (GaSe) nanosheet networks by stoichiometric transfer of laser vaporized material from bulk GaSe targets in Ar background gas. Uniform coverage of interconnected, crystalline, few-layer, photoresponsive GaSe nanosheets in both in-plane and out-of-plane orientations were achieved under different ablation plume conditions over ~1.5 cm2 areas. Plume propagation was characterized by in situ ICCD-imaging. High (1 Torr) Ar background gas pressures were found to be crucial for the stoichiometric growth of GaSe nanosheet networks. Individual 1-3 layer GaSe triangular nanosheets of ~ 200 nm domain size were formed within 30 laser pulses, coalescing to form nanosheet networks in as few as 100 laser pulses. The thickness of the deposited networks increased linearly with pulse number, adding layers in a two-dimensional (2D) growth mode while maintaining a surface roughness of 2 GaSe layers for increasing overall thickness. Field effect transistors using these interconnected crystalline GaSe networks showed p-type semiconducting characteristics with mobilities reaching as high as 0.1 cm2V-1s-1. Spectrally-resolved photoresponsivities and external quantum efficiencies ranged from 0.4 AW-1 and 100% at 700 nm, to 1.4 AW-1 and 600 % at 240 nm, respectively. Pulsed laser deposition under these conditions appears to provide a versatile and rapid approach to stoichiometrically transfer and deposit photoresponsive networks of 2D nanosheets with digital thickness control and substrate-scale uniformity for a variety of applications.

Mahjouri-Samani, Masoud [ORNL; Gresback, Ryan G [ORNL; Tian, Mengkun [ORNL; Puretzky, Alexander A [ORNL; Rouleau, Christopher M [ORNL; Eres, Gyula [ORNL; Ivanov, Ilia N [ORNL; Xiao, Kai [ORNL; McGuire, Michael A [ORNL; Duscher, Gerd [University of Tennessee, Knoxville (UTK); Geohegan, David B [ORNL

2014-01-01T23:59:59.000Z

320

Pulsed Power Technology at Sandia National Laboratories  

NLE Websites -- All DOE Office Websites (Extended Search)

Z-Machine Time-exposure photograph of electrical flashover arcs produced over the surface of the water in the accelerator tank as a byproduct of Z operation. These flashovers are much like strokes of lightning Related links Electromagnetic Technology at Sandia National Laboratories Pulsed Power Technology Published Papers Inertial Fusion Energy C. L. Olson, "Inertial Fusion Energy with Pulsed Power," 2000 Codes: ALEGRA K. C. Cochrane, "Aluminum Equation of State Validation and Verification for the ALEGRA HEDP Simulation Code," 2006 T. Trucano, "ALEGRA-HEDP Validation Strategy," 2005 C. Garasi , "Multi-dimensional high energy density physics modeling and simulation of wire array z-pinch physics," 2003 Equation of State (EOS)

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Fuselage disbond inspection procedure using pulsed thermography  

Science Journals Connector (OSTI)

One use of pulsed thermography that has shown promise in aircraft inspection for some time is an inspection for disbonds in metallic structures. The FAA has funded research at Wayne State University in this area and Boeing identified a specific inspection requirement for disbonds on Boeing 747 aircraft. Laboratory and subsequent field testing monitored by the AANC has demonstrated the reliability of this type of inspection. As a result Boeing expects to approve a general fuselage disbond inspection procedure using pulsed thermography in the 2nd Quarter of 2001.

Mike Ashbaugh; Jeffrey G. Thompson

2002-01-01T23:59:59.000Z

322

Dispersion compensation for attosecond electron pulses  

SciTech Connect

We propose a device to compensate for the dispersion of attosecond electron pulses. The device uses only static electric and magnetic fields and therefore does not require synchronization to the pulsed electron source. Analogous to the well-known optical dispersion compensator, an electron dispersion compensator separates paths by energy in space. Magnetic fields are used as the dispersing element, while a Wien filter is used for compensation of the electron arrival times. We analyze a device with a size of centimeters, which can be applied to ultrafast electron diffraction and microscopy, and fundamental studies.

Hansen, Peter; Baumgarten, Cory; Batelaan, Herman; Centurion, Martin [Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States)

2012-08-20T23:59:59.000Z

323

Evanescent-wave coupled right angled buried waveguide: Applications in carbon nanotube mode-locking  

SciTech Connect

We present an evanescent-field device based on a right-angled waveguide. This consists of orthogonal waveguides, with their points of intersection lying along an angled facet of the chip. Light guided along one waveguide is incident at the angled dielectric-air facet at an angle exceeding the critical angle, so that the totally internally reflected light is coupled into the second waveguide. By depositing a nanotube film on the angled surface, the chip is then used to mode-lock an Erbium doped fiber ring laser with a repetition rate of 26?MHz, and pulse duration of 800?fs.

Mary, R.; Thomson, R. R.; Kar, A. K., E-mail: a.k.kar@hw.ac.uk [Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Brown, G. [Optoscribe Ltd, 0/14 Alba Innovation Centre, Alba Campus, Livingston EH54 7GA (United Kingdom)] [Optoscribe Ltd, 0/14 Alba Innovation Centre, Alba Campus, Livingston EH54 7GA (United Kingdom); Beecher, S. J. [Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ (United Kingdom)] [Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ (United Kingdom); Popa, D.; Sun, Z.; Torrisi, F.; Hasan, T.; Milana, S.; Bonaccorso, F.; Ferrari, A. C. [Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA (United Kingdom)] [Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA (United Kingdom)

2013-11-25T23:59:59.000Z

324

Chamber transport of ''foot'' pulses for heavy-ion fusion  

SciTech Connect

Indirect-drive targets for heavy-ion fusion must initially be heated by ''foot'' pulses that precede the main heating pulses by tens of nanoseconds. These pulses typically have a lower energy and perveance than the main pulses, and the fusion-chamber environment is different from that seen by later pulses. The preliminary particle-in-cell simulations of foot pulses here examine the sensitivity of the beam focusing to ion-beam perveance, background-gas density, and pre-neutralization by a plasma near the chamber entry port.

Sharp, W.M.; Callahan-Miller, D.A.; Tabak, M.; Yu, S.S.; Peterson, P.F.

2002-02-20T23:59:59.000Z

325

Mode I - mode II delamination fractrue toughness of a unidirectional graphite/epoxy composite  

E-Print Network (OSTI)

MODE I - MODE II DELAMINATION FRACTURE TOUGHNESS OF A UNIDIRECTIONAL GRAPHITE/EPOXY COMPOSITE A Thesis by PETER STEPHEN VANDERKLEY Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE Demember 1981 Najor Subject: Mechanical Engineering MODE I - MODE II DELAMINATION FRACTURE TOUGHNESS OF A UNIDIRECTIONAL GRAPHITE/EPOXY COMPOSITE A Thesis by PETER STEPHEN VANDERKLEY Approved as to style and content by...

Vanderkley, Peter Stephen

2012-06-07T23:59:59.000Z

326

New proofs for old modes Mark Wooding  

E-Print Network (OSTI)

the standard block cipher modes of operation: CBC, CFB, and OFB and analyse their security. We don't look in (full­width) CFB and OFB modes and that generalized counters encrypted using the block cipher (with Ciphertext feedback (CFB) en­ cryption 19 4.1 Description . . . . . . . . . 19 4.2 Sliding strings

327

New proofs for old modes Mark Wooding  

E-Print Network (OSTI)

the standard block cipher modes of operation: CBC, CFB, and OFB and analyse their security. We don't look in (full-width) CFB and OFB modes and that generalized counters encrypted using the block cipher (with Ciphertext feedback (CFB) en- cryption 19 4.1 Description . . . . . . . . . 19 4.2 Sliding strings

328

Deuteron as a Skyrmion with a generalized mass term  

SciTech Connect

We calculate the energies of the B=1 and B=2 Skyrmions with a generalized mass term proposed in [V. B. Kopeliovich, B. Piette, and W. J. Zakrzewski, Phys. Rev. D 73, 014006 (2006).], allowing for (iso-)rotational deformations within the axially-symmetric ansatz. We show that this modification of the chiral symmetry breaking term is not sufficient to accommodate for the experimental value of the binding energy of the deuteron. Also, a computation of the different vibrational modes and energies reveals how the deuteron rigidity is affected as a function of the mass parameter D.

Bonenfant, Eric; Marleau, Luc [Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec, G1K 7P4 (Canada)

2009-12-01T23:59:59.000Z

329

The Normal Modes of the Earth Lapo Boschi (lapo@erdw.ethz.ch)  

E-Print Network (OSTI)

) is given by Newton's law of gravitation, ¨u(r, t) = V r - r |r - r|3 G(r )d3 r , (1) with G denoting Newton, with associated eigenfrequencies: the normal modes (free oscillations) of the Earth. Self-Gravitation to the gravity field caused by the Earth's deformation u(r, t) itself ("self-gravitation"). Those terms, how

Boschi, Lapo

330

A NEW METHOD OF PULSE-WISE SPECTRAL ANALYSIS OF GAMMA-RAY BURSTS  

SciTech Connect

Time-resolved spectral analysis, though a very promising method to understand the emission mechanism of gamma-ray bursts (GRBs), is difficult to implement in practice because of poor statistics. We present a new method for pulse-wise time-resolved spectral study of the individual pulses of GRBs, using the fact that many spectral parameters are either constants or smooth functions of time. We use this method for the two pulses of GRB 081221, the brightest GRB with separable pulses. We choose, from the literature, a set of possible models that includes the Band model, blackbody with a power law (BBPL), and a collection of blackbodies with a smoothly varying temperature profile, along with a power law (mBBPL), and two blackbodies with a power law (2BBPL). First, we perform a time-resolved study to confirm the spectral parameter variations, and then we construct the new model to perform a joint spectral fit. We find that any photospheric emission in terms of blackbodies is required mainly in the rising parts of the pulses and the falling part can be adequately explained in terms of the Band model, with the low-energy photon index within the regime of synchrotron model. Interestingly, we find that 2BBPL is comparable or sometimes even better, though marginally, than the Band model, in all episodes. Consistent results are also obtained for the brightest GRB of Fermi era-GRB 090618. We point out that the method is generic enough to test any spectral model with well-defined parameter variations.

Basak, Rupal; Rao, A. R., E-mail: rupalb@tifr.res.in, E-mail: arrao@tifr.res.in [Tata Institute of Fundamental Research, Mumbai-400005 (India)

2013-05-10T23:59:59.000Z

331

2009 Raj JainCSE571SWashington University in St. Louis Modes ofModes of  

E-Print Network (OSTI)

, CFB, CTR 2. Privacy+Integrity 3. DES Attacks 4. 3DES and its design Ref: Chapter 4 of textbook. #12. Electronic Code Book (ECB) 2. Cipher Block Chaining (CBC) 3. Cipher Feedback Mode (CFB) 4. Output Feedback University in St. Louis 4. k4. k--Bit Cipher Feedback Mode (CFB)Bit Cipher Feedback Mode (CFB) ! Key Stream

Jain, Raj

332

Vibration modes and acoustic noise in a 4-phase switched reluctance motor  

SciTech Connect

Acoustic noise in the switched reluctance motor is caused primarily by the deformation of the stator lamination stack. Acoustic noise is most severe when the periodic excitation of the SRM phases excites a natural vibration mode of the stack. The natural vibration modes and frequencies of a 4-phase, 8/6 switched reluctance motor are examined. Structural finite element analysis is used to compute the natural modes and frequencies. Impulse tests on the stator stack verify the calculations and show which modes are excited. Heuristic arguments are developed to predict the operating conditions that will excite the natural modes. Measurement of vibration while the machine is under load shows which operating conditions excite the natural modes and verifies the predictions. An approximate formula is derived to predict the frequency of the fundamental vibration mode in terms of lamination dimensions and material properties. The formula is validated by comparison with finite element calculations for several laminations, and hence is shown to be useful in design trade-off studies.

Colby, R.S. [United Technologies Research Center, East Hartford, CT (United States); Mottier, F. [Mottier (Francois), West Hartford, CT (United States); Miller, T.J.E. [Univ. of Glasgow (United Kingdom). Dept. of Electronics and Electrical Engineering

1995-12-31T23:59:59.000Z

333

Performance Assessment of Single Electrode-Supported Solid Oxide Cells Operating in the Steam Electrolysis Mode  

SciTech Connect

An experimental study is under way to assess the performance of electrode-supported solid-oxide cells operating in the steam electrolysis mode for hydrogen production. Results presented in this paper were obtained from single cells, with an active area of 16 cm{sup 2} per cell. The electrolysis cells are electrode-supported, with yttria-stabilized zirconia (YSZ) electrolytes ({approx}10 {mu}m thick), nickel-YSZ steam/hydrogen electrodes ({approx}1400 {mu}m thick), and modified LSM or LSCF air-side electrodes ({approx}90 {mu}m thick). The purpose of the present study is to document and compare the performance and degradation rates of these cells in the fuel cell mode and in the electrolysis mode under various operating conditions. Initial performance was documented through a series of voltage-current (VI) sweeps and AC impedance spectroscopy measurements. Degradation was determined through long-term testing, first in the fuel cell mode, then in the electrolysis mode. Results generally indicate accelerated degradation rates in the electrolysis mode compared to the fuel cell mode, possibly due to electrode delamination. The paper also includes details of an improved single-cell test apparatus developed specifically for these experiments.

X. Zhang; J. E. O'Brien; R. C. O'Brien; N. Petigny

2011-11-01T23:59:59.000Z

334

Pulse radiolysis of solutions of sodium tetraphenylborate  

SciTech Connect

Pulse radiolysis of solutions of sodium tetraphenylborate (NaBPh/sub 4/) indicates that the absorption observed in organic amides with lambda/sub max/ in the range 650-724 nm is not due to Na/sup -/, an electron adduct to BPh/sub 4//sup -/, a triplet excited state, or a proton-donating solvent cation. Experiments in aqueous solution are described in which the reactions of selected radicals with NaBPh/sub 4/ are studied. One-electron oxidation of NaBPh/sub 4/ by N/sub 3//sup .-/ radicals yields a species, assumed to be NaBPh/sub 4//sup ./, with absorption maxima at 335 and 800 nm. A similar spectrum is observed on pulse radiolysis of solutions of NaBPh/sub 4/ in tetramethylurea (TMU), but the long-wavelength absorption is shifted to 725 nm. The formation of an oxidizing radical in irradiated TMU was confirmed by the observation of I/sub 2//sup .-/ on pulse radiolysis of solutions of KI in this solvent. Pulse radiolysis of solution of NaBPh/sub 4/ and KI in TMU demonstrated that these solutes compete for the oxidizing intermediate.

Liu, K.J.; Langan, J.R.; Salmon, G.A.; Holton, D.M.; Edwards, P.P.

1988-05-05T23:59:59.000Z

335

Pressure wave charged repetitively pulsed gas laser  

DOE Patents (OSTI)

A repetitively pulsed gas laser in which a system of mechanical shutters bracketing the laser cavity manipulate pressure waves resulting from residual energy in the cavity gas following a lasing event so as to draw fresh gas into the cavity and effectively pump spent gas in a dynamic closed loop.

Kulkarny, Vijay A. (Redondo Beach, CA)

1982-01-01T23:59:59.000Z

336

E-Print Network 3.0 - army pulse radiation Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

. This communication scheme is based upon chaotic signals in the form of pulse trains where intervals between... the pulses are determined by chaotic dynamics of a pulse...

337

Gravitational-wave modes from precessing black-hole binaries  

E-Print Network (OSTI)

Gravitational waves from precessing black-hole binaries exhibit features that are absent in nonprecessing systems. The most prominent of these is a parity-violating asymmetry that beams energy and linear momentum preferentially along or opposite to the orbital angular momentum, leading to recoil of the binary. The asymmetry will appear as amplitude and phase modulations at the orbital frequency. For strongly precessing systems, it accounts for at least 3% amplitude modulation for binaries in the sensitivity band of ground-based gravitational-wave detectors, and can exceed 50% for massive systems. Such asymmetric features are also clearly visible when the waves are decomposed into modes of spin-weighted spherical harmonics, and are inherent in the waves themselves---rather than resulting from residual eccentricity in numerical simulations, or from mode-mixing due to precession. In particular, there is generically no instantaneous frame for which the mode decomposition will have any symmetry. We introduce a method to simplify the expressions for waveforms given in analytical relativity, which can be used to combine existing high-order waveforms for nonprecessing systems with expressions for the precessing contributions, leading to improved accuracy and a unified treatment of precessing and nonprecessing binaries. Using this method, it is possible to clarify the nature and the origins of the asymmetries and show the effects of asymmetry on recoils more clearly. We present post-Newtonian (PN) expressions for the waveform modes that include these terms, complete to the relative 2PN level in spin (proportional to $v^4/c^4$ times a certain combination of the spins). Comparing the results of those expressions to numerical results, we find good qualitative agreement. We also demonstrate how these expressions can be used to efficiently calculate waveforms for gravitational-wave astronomy.

Michael Boyle; Lawrence E. Kidder; Serguei Ossokine; Harald P. Pfeiffer

2014-09-15T23:59:59.000Z

338

Femtosecond laser pulse shaping by use of microsecond radio-frequency pulses  

Science Journals Connector (OSTI)

We demonstrate a new pulse-shaping technique, using an acousto-optic modulator as a spatial modulator in a zero-dispersion delay line. Compared with existing techniques, this approach...

Hillegas, C W; Tull, J X; Goswami, D; Strickland, D; Warren, W S

1994-01-01T23:59:59.000Z

339

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. Interaction of the ALS electron beam with a femtosecond laser pulse as they co-propagate through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration as the laser pulse. This causes a dispersion of the electron trajectories, and the bunch develops a hole that emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. The technique allows tremendous flexibility in shaping the terahertz pulses by appropriate modulation of the laser pulse.

340

Sensitivity Enhancement System for Pulse Compression Weather Radar  

Science Journals Connector (OSTI)

The use of low-power solid state transmitters in weather radar to keep costs down requires pulse compression technique in order to maintain an adequate minimum detectable signal. However, wide-band pulse compression filters will partly reduce the ...

Cuong M. Nguyen; V. Chandrasekar

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Frequency content of current pulses in slapper detonator bridges  

SciTech Connect

DFT amplitudes are obtained for digital current pulse files. The frequency content of slapper detonator bridge current pulses is obtained. The frequencies are confined well within the passband of the CVR used to sample them.

Carpenter, K H

2006-12-18T23:59:59.000Z

342

A forevacuum pulse arc-discharge-based plasma electron source  

Science Journals Connector (OSTI)

An arc-discharge-based electron source is described, which is designed for forming a pulsed wideaperture electron beam in the forevacuum pressure range (4...2 in the submillisecond range of pulse durations. The c...

A. V. Kazakov; V. A. Burdovitsin; A. V. Medovnik

2013-11-01T23:59:59.000Z

343

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. Interaction of the ALS electron beam with a femtosecond laser pulse as they co-propagate through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration as the laser pulse. This causes a dispersion of the electron trajectories, and the bunch develops a hole that emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. The technique allows tremendous flexibility in shaping the terahertz pulses by appropriate modulation of the laser pulse.

344

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. Interaction of the ALS electron beam with a femtosecond laser pulse as they co-propagate through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration as the laser pulse. This causes a dispersion of the electron trajectories, and the bunch develops a hole that emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. The technique allows tremendous flexibility in shaping the terahertz pulses by appropriate modulation of the laser pulse.

345

Time-domain squeezing and quantum distributions in the pulsed regime  

SciTech Connect

We investigate time-dependent properties of Einstein-Podolsky-Rosen (EPR) light beams generated in a nondegenerate optical parametric oscillator (NOPO) driven by a sequence of laser pulses with Gaussian time-dependent envelopes. This investigation continues our previous analysis [H. H. Adamyan and G. Yu. Kryuchkyan, Phys. Rev. A 74, 023810 (2006)] and involves problems of two-mode quadrature squeezing as well as intensity-difference squeezing in the time domain. The peculiarities of EPR beams are also discussed in the framework of phase-space quantum distributions. Two kinds of non-Gaussian Wigner functions, for the reduced one-mode state of periodically pulsed NOPO and for EPR beams which are combined on a one-half beam splitter are calculated numerically. We also investigate the Wigner functions of intensity-correlated twin beams following the conditional photon state-preparation scheme. It is demonstrated that the Wigner functions involve negative values in parts of the phase space for the schemes with one, two, and three photons.

Adamyan, N. H. [Yerevan State University, 1 A Manoogian, 375049 Yerevan (Armenia); Adamyan, H. H. [Institute for Physical Research, National Academy of Sciences, Ashtarak-2, 378410 (Armenia); Kryuchkyan, G. Yu. [Yerevan State University, 1 A Manoogian, 375049 Yerevan (Armenia); Institute for Physical Research, National Academy of Sciences, Ashtarak-2, 378410 (Armenia)

2008-02-15T23:59:59.000Z

346

Guiding Center Equations for Ideal Magnetohydrodynamic Modes  

SciTech Connect

Guiding center simulations are routinely used for the discovery of mode-particle resonances in tokamaks, for both resistive and ideal instabilities and to find modifications of particle distributions caused by a given spectrum of modes, including large scale avalanches during events with a number of large amplitude modes. One of the most fundamental properties of ideal magnetohydrodynamics is the condition that plasma motion cannot change magnetic topology. The conventional representation of ideal magnetohydrodynamic modes by perturbing a toroidal equilibrium field through ?~B = ? X (? X B) however perturbs the magnetic topology, introducing extraneous magnetic islands in the field. A proper treatment of an ideal perturbation involves a full Lagrangian displacement of the field due to the perturbation and conserves magnetic topology as it should. In order to examine the effect of ideal magnetohydrodynamic modes on particle trajectories the guiding center equations should include a correct Lagrangian treatment. Guiding center equations for an ideal displacement ? are derived which perserve the magnetic topology and are used to examine mode particle resonances in toroidal confinement devices. These simulations are compared to others which are identical in all respects except that they use the linear representation for the field. Unlike the case for the magnetic field, the use of the linear field perturbation in the guiding center equations does not result in extraneous mode particle resonances.

Roscoe B. White

2013-02-21T23:59:59.000Z

347

Arrangement for studying pulsed cold emission of electrons  

SciTech Connect

An arrangement is presented for studying pulsed, cold electron emission which is composed of the following components: a generator unit for high-voltage rectangular pulses that permits a series of pulses of negative and positive polarity to be obtained in which the duration can be smoothly varied from 5 usec to 5 sec at amplitudes from 0 to 38 kV, and also a sensitive circuit for registering weak pulses of the emission currents.

Egorov, N.V.; Kallistov, K.O.; Kharitonov, O.A.

1985-10-01T23:59:59.000Z

348

Control of XeF laser output by pulse injecton  

SciTech Connect

Injection locking is investigated as a means for control of optical pulse duration and polarization in a XeF laser. Intense short-pulse generation in the ultraviolet is achieved by injection of a low-level 1-ns optical pulse into a XeF oscillator. Control of laser output polarization by injection locking is demonstrated and studied as a function of injected signal level. Enhancement of XeF electric-discharge laser efficiency by injection pulse ''priming'' is observed.

Pacala, T.J.; Christensen, C.P.

1980-04-15T23:59:59.000Z

349

Photon statistics of atomic fluorescence after {pi}-pulse excitation  

SciTech Connect

The photon statistics of atomic fluorescence after {pi}-pulse excitation is investigated in a system in which the input and output ports are connected to an atom. Since spontaneous decay during input pulse excitation occurs, the output pulse generally contains a multiphoton component with a certain probability. We quantitatively evaluate the probability of the output pulse containing multiple photons and determine the conditions for ideal single-photon generation.

Yoshimi, Kazuyoshi [College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa, Chiba 272-0827 (Japan); Koshino, Kazuki [College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa, Chiba 272-0827 (Japan); PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan)

2010-09-15T23:59:59.000Z

350

Optimization of Weld Bead Penetration in Pulsed Gas Metal Arc Welding using Genetic Algorithm  

E-Print Network (OSTI)

Abstract The weld quality is highly influenced by various process parameters involved in the process. This can be achieved by meeting quality requirements of bead geometry. Inadequate depth of penetration will contribute to failure of the welded structure. This paper presents the development of genetic algorithm model for the optimization of depth of penetration of weld bead geometry in pulsed gas metal arc welding process. The model is based on experimental data. The thickness of the plate, pulse frequency, wire feed rate, wire feed rate/travel speed ratio, and peak current have been considered as the process parameters to maximize the bead penetration depth. Optimization of process parameters was done using GA. The developed model is then compared with experimental results and it is found that the results obtained from genetic algorithm model are accurate. The optimal process parameters gave a value of 5.314 for depth of penetration which demonstrates an accuracy of 1.33 % and thus the effectiveness of the model presented. The obtained results help in selecting quickly the process parameters to achieve the desired quality. KeywordsGenetic algorithm, Pulsed GMA welding, Welding parameters, Depth of penetration, Regression mode I.

K. Manikya Kanti; P. Srinivasa Rao; G. Ranga Janardhana

351

Long-Term Stewardship Study  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Office of Long Term Stewardship Office of Long Term Stewardship LONG-TERM STEWARDSHIP STUDY Volume I - Report Prepared to comply with the terms of a settlement agreement: Natural Resources Defense Council, et al. v. Richardson, et al., Civ. No. 97-936 (SS) (D.D.C. Dec. 12, 1998). Final Study October 2001 - i - Foreword The Department of Energy (DOE) has prepared this Long-term Stewardship Study ("Study" or "Final Study") to comply with the terms of a settlement agreement between DOE, the Natural Resources Defense Council, and 38 other plaintiffs [Natural Resources Defense Council, et al. v. Richardson, et al., Civ. No. 97-936 (SS) (D.D.C. Dec. 12, 1998)]. The Study describes and analyzes several issues and a variety of information associated with long-term stewardship. The Study

352

Mixed Mode Fuel Injector And Injection System  

DOE Patents (OSTI)

A fuel injector includes a homogenous charge nozzle outlet set and a conventional nozzle outlet set that are controlled respectively by first and second three way needle control valves. Each fuel injector includes first and second concentric needle valve members. One of the needle valve members moves to an open position for a homogenous charge injection event, while the other needle valve member moves to an open position for a conventional injection event. The fuel injector has the ability to operate in a homogenous charge mode with a homogenous charge spray pattern, a conventional mode with a conventional spray pattern or a mixed mode.

Stewart, Chris Lee (Normal, IL); Tian, Ye (Bloomington, IL); Wang, Lifeng (Normal, IL); Shafer, Scott F. (Morton, IL)

2005-12-27T23:59:59.000Z

353

TRANSIENT FLOW ANALYSIS OF FILLING IN PULSE DETONATION  

E-Print Network (OSTI)

TRANSIENT FLOW ANALYSIS OF FILLING IN PULSE DETONATION ENGINE by VEERA VENKATA SUNEEL JINNALA. November 20, 2009 #12;iv ABSTRACT TRANSIENT FLOW ANALYSIS OF FILLING IN PULSE DETONATION ENGINE Veera The Pulse Detonation Engine (PDE) is considered to be a propulsion system of future air vehicles

Texas at Arlington, University of

354

MICROSECOND-SCALE ELECTRIC FIELD PULSES IN CLOUD LIGHTNING FLASHES  

E-Print Network (OSTI)

-149- 30F3 MICROSECOND-SCALE ELECTRIC FIELD PULSES IN CLOUD LIGHTNING FLASHES Y. Villanueva, V tape-recorded data) for ground flashes by Rakov et al. [5]. Note that the K process in a lightning-scale pulses in different stages of cloud flashes in Florida and New Mexico are analyzed. The pulse occurrence

Florida, University of

355

Transportable automated ammonia sensor based on a pulsed thermoelectrically cooled  

E-Print Network (OSTI)

Transportable automated ammonia sensor based on a pulsed thermoelectrically cooled quantum single-frequency, thermoelectrically cooled, pulsed quantum-cascade laser with an embedded distributed absorption spectroscopy with a pulsed QC DFB laser was reported in Ref. 3, where wavelength modulation

356

The jamming avoidance response in gymnotoid pulse-species: A mechanism to minimize the probability of pulse-train coincidence  

Science Journals Connector (OSTI)

Gymnotoid electric fish with pulse-type electric organ discharges (EODs) shorten (lengthen) their EOD intervals as pulses of a slightly slower ... coincidence by transient accelerations (decelerations) of their EOD

Walter Heiligenberg; Curtis Baker; Joseph Bastian

1978-01-01T23:59:59.000Z

357

Field Quantization, Photons and Non-Hermitean Modes  

E-Print Network (OSTI)

Field quantization in three dimensional unstable optical systems is treated by expanding the vector potential in terms of non-Hermitean (Fox-Li) modes in both the cavity and external regions. The cavity non-Hermitean modes (NHM) are treated using the paraxial and monochromaticity approximations. The NHM bi-orthogonality relationships are used in a standard canonical quantization procedure based on introducing generalised coordinates and momenta for the electromagnetic (EM) field. The quantum EM field is equivalent to a set of quantum harmonic oscillators (QHO), associated with either the cavity or the external region NHM. This confirms the validity of the photon model in unstable optical systems, though the annihilation and creation operators for each QHO are not Hermitean adjoints. The quantum Hamiltonian for the EM field is the sum of non-commuting cavity and external region contributions, each of which is sum of independent QHO Hamiltonians for each NHM, but the external field Hamiltonian also includes a coupling term responsible for external NHM photon exchange processes. Cavity energy gain and loss processes is associated with the non-commutativity of cavity and external region operators, given in terms of surface integrals involving cavity and external region NHM functions on the cavity-external region boundary. The spontaneous decay of a two-level atom inside an unstable cavity is treated using the essential states approach and the rotating wave approximation. Atomic transitions leading to cavity NHM photon absorption have a different coupling constant to those leading to photon emission, a feature resulting from the use of NHM functions. Under certain conditions the decay rate is enhanced by the Petermann factor.

S. A. Brown; B. J. Dalton

2001-09-10T23:59:59.000Z

358

Performance degradation of Geiger-mode APDs at cryogenic temperatures  

E-Print Network (OSTI)

Two-phase Cryogenic Avalanche Detectors (CRADs) with THGEM multipliers, optically read out with Geiger-mode APDs (GAPDs), were proposed as potential technique for charge recording in rare-event experiments. In this work we report on the degradation of the GAPD performance at cryogenic temperatures revealed in the course of the study of two-phase CRAD in Ar, with combined THGEM/GAPD-matrix multiplier; the GAPDs recorded secondary scintillation photons from the THGEM holes in the Near Infrared. The degradation effect, namely the loss of the GAPD pulse amplitude, depended on the incident X-ray photon flux. The critical counting rate of photoelectrons produced at the 4.4 mm2 GAPD, degrading its performance at 87 K, was estimated as 10000 per second. This effect was shown to result from the considerable increase of the pixel quenching resistor of this CPTA-made GAPD type. Though not affecting low-rate rare-event experiments, the observed effect may impose some limitations on the performance of CRADs with GAPD-base...

Bondar, A; Dolgov, A; Shekhtman, L; Shemyakina, E; Sokolov, A; Breskin, A; Thers, D

2014-01-01T23:59:59.000Z

359

Differential rotation of nonlinear r-modes  

Science Journals Connector (OSTI)

The differential rotation of r-modes is investigated within the nonlinear theory up to second order in the mode amplitude in the case of a slowly rotating, Newtonian, barotropic, perfect-fluid star. We find a nonlinear extension of the linear r-mode, which represents differential rotation that produces large scale drifts of fluid elements along stellar latitudes. This solution includes a piece induced by first-order quantities and another one that is a pure second-order effect. Since the latter is stratified on cylinders, it cannot cancel differential rotation induced by first-order quantities, which is not stratified on cylinders. It is shown that, unlike the situation in the linearized theory, r-modes do not preserve the vorticity of fluid elements at second order. It is also shown that the physical angular momentum and energy of the perturbation are, in general, different from the corresponding canonical quantities.

Paulo M. S

2004-04-02T23:59:59.000Z

360

PLASTIC DEFORMATIONPLASTIC DEFORMATION Modes of Deformation  

E-Print Network (OSTI)

PLASTIC DEFORMATIONPLASTIC DEFORMATION Modes of Deformation The Uniaxial Tension Test Mechanisms underlying Plastic Deformation Strengthening mechanisms Mechanical Metallurgy George E Dieter McClick here to know about all the mechanisms by which materials fail #12;Slip (Dislocation motion) Plastic

Subramaniam, Anandh

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Whispering-gallery-mode-based seismometer  

SciTech Connect

A whispering-gallery-mode-based seismometer provides for receiving laser light into an optical fiber, operatively coupling the laser light from the optical fiber into a whispering-gallery-mode-based optical resonator, operatively coupling a spring of a spring-mass assembly to a housing structure; and locating the whispering-gallery-mode-based optical resonator between the spring-mass assembly and the housing structure so as to provide for compressing the whispering-gallery-mode-based optical resonator between the spring-mass assembly and the housing structure responsive to a dynamic compression force from the spring-mass assembly responsive to a motion of the housing structure relative to an inertial frame of reference.

Fourguette, Dominique Claire; Otugen, M Volkan; Larocque, Liane Marie; Ritter, Greg Aan; Meeusen, Jason Jeffrey; Ioppolo, Tindaro

2014-06-03T23:59:59.000Z

362

Rotary Mode Core Sample System availability improvement  

SciTech Connect

The Rotary Mode Core Sample System (RMCSS) is used to obtain stratified samples of the waste deposits in single-shell and double-shell waste tanks at the Hanford Site. The samples are used to characterize the waste in support of ongoing and future waste remediation efforts. Four sampling trucks have been developed to obtain these samples. Truck I was the first in operation and is currently being used to obtain samples where the push mode is appropriate (i.e., no rotation of drill). Truck 2 is similar to truck 1, except for added safety features, and is in operation to obtain samples using either a push mode or rotary drill mode. Trucks 3 and 4 are now being fabricated to be essentially identical to truck 2.

Jenkins, W.W.; Bennett, K.L.; Potter, J.D. [Westinghouse Hanford Co., Richland, WA (United States); Cross, B.T.; Burkes, J.M.; Rogers, A.C. [Southwest Research Institute (United States)

1995-02-28T23:59:59.000Z

363

Two-Mode Theory of BEC Interferometry  

E-Print Network (OSTI)

A theory of BEC interferometry in an unsymmetrical double-well trap has been developed for small boson numbers, based on the two-mode approximation. The bosons are initially in the lowest mode of a single well trap, which is split into a double well and then recombined. Possible fragmentations into separate BEC states in each well during the splitting/recombination process are allowed for. The BEC is treated as a giant spin system, the fragmented states are eigenstates of S^2 and Sz. Self-consistent sets of equations for the amplitudes of the fragmented states and for the two single boson mode functions are obtained. The latter are coupled Gross-Pitaevskii equations. Interferometric effects may be measured via boson numbers in the first excited mode

B J Dalton

2007-02-03T23:59:59.000Z

364

Texas Feedgrain Flows and Transportation Modes, 1974.  

E-Print Network (OSTI)

ELEVATO RS AND FEEDMILLS . . . Destinations ............................ . .... . . . Modes of Transpo rtation of Grain Shipments ... .. . Destinations of Intraregi on and Interregion S Modes o f Transportation of Intraregion and Interregion Shipments.... Texas feedyards, receiving almost 31 per cent of the grain sorghum shipments of the elevators, ranked as the second most important market outlet. The remainder of the shipments was to out-of-state destinations (6.4 percent) and other Texas elevators...

Fuller, Stephen W.; Knudson, L. Bruce

1977-01-01T23:59:59.000Z

365

Electroweak strings, zero modes and baryon number  

Science Journals Connector (OSTI)

The Dirac equations for leptons and quarks in the background of an electroweak Zstring have zero mode solutions. If two loops of electroweak string are linked, the zero modes on one of the loops interacts with the other loop via an Aharanov-Bohm interaction. The effects of this interaction are briefly discussed and it is shown that the fermions induce a baryon number on linked loops of Zstring.

Tanmay Vachaspati

1995-01-01T23:59:59.000Z

366

Pulse Combustor Design, A DOE Assessment  

NLE Websites -- All DOE Office Websites (Extended Search)

Pulse Combustor Design Pulse Combustor Design A DOE Assessment DOE/NETL-2003/1190 July 2003 U.S. Department of Energy National Energy Technology Laboratory P.O. Box 880, 3610 Collins Ferry Road Morgantown, WV 26507-0880 P.O. Box 10940, 626 Cochrans Mill Road Pittsburgh, PA 15236-0940 West Third Street, Suite 1400 Tulsa, OK 74103-3519 website: www.netl.doe.gov 2 Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or

367

Sandia National Laboratories: Z Pulsed Power Facility  

NLE Websites -- All DOE Office Websites (Extended Search)

Z-Machine Z-Machine About Z Z Research Z News Contact Us Facebook Twitter YouTube Flickr RSS Z-Machine Z Pulsed Power Facility Science serving the nation Created to validate nuclear weapons models, the Z machine is also in the race for viable fusion energy. Z-Machine From Earth's Core to Black Holes Contributing to discovery science by studying matter at conditions found nowhere else on Earth Center of Z About Z Sandia's Z machine is the world's most powerful and efficient laboratory radiation source. It uses high magnetic fields associated with high electrical currents to produce high temperatures, high pressures, and powerful X-rays for research in high energy density science. The Z machine creates conditions found nowhere else on Earth. Z is part of Sandia's Pulsed Power program, which began in the 1960s.

368

Pulsed Power Technology at Sandia National Laboratories  

NLE Websites -- All DOE Office Websites (Extended Search)

News and Reviews News and Reviews Pulsed Power in the News Nuclear fusion simulation shows high-gain energy output (March 2012) Rapid-fire pulse brings Sandia Z method closer to goal of high-yield fusion reactor (April 2007) Ice created in nanoseconds by Sandia's Z machine (March 2007) Z-Machine Shockwaves Melt Diamond (November 2006) Phase diagram of water revised by Sandia researchers (October 2006) Z fires objects faster than Earth moves through space (June 6, 2005) Sandia imagists view imploding wire arrays on Z (November 10, 2004) Z's $61.7 million refurbishment to advance capabilities (October 21, 2004) Z produces fusion neutrons (April 7, 2003) Former shock physics manager (Asay) elected to NAE (February 20, 2003) Z-Beamlet image shows Z evenly compresses pellet (August 30, 2001)

369

A method to synchronize signals from multiple patient monitoring devices through a single input channel for inclusion in list-mode acquisitions  

SciTech Connect

Purpose: This technical note documents a method that the authors developed for combining a signal to synchronize a patient-monitoring device with a second physiological signal for inclusion into list-mode acquisition. Our specific application requires synchronizing an external patient motion-tracking system with a medical imaging system by multiplexing the tracking input with the ECG input. The authors believe that their methodology can be adapted for use in a variety of medical imaging modalities including single photon emission computed tomography (SPECT) and positron emission tomography (PET). Methods: The authors insert a unique pulse sequence into a single physiological input channel. This sequence is then recorded in the list-mode acquisition along with the R-wave pulse used for ECG gating. The specific form of our pulse sequence allows for recognition of the time point being synchronized even when portions of the pulse sequence are lost due to collisions with R-wave pulses. This was achieved by altering our software used in binning the list-mode data to recognize even a portion of our pulse sequence. Limitations on heart rates at which our pulse sequence could be reliably detected were investigated by simulating the mixing of the two signals as a function of heart rate and time point during the cardiac cycle at which our pulse sequence is mixed with the cardiac signal. Results: The authors have successfully achieved accurate temporal synchronization of our motion-tracking system with acquisition of SPECT projections used in 17 recent clinical research cases. In our simulation analysis the authors determined that synchronization to enable compensation for body and respiratory motion could be achieved for heart rates up to 125 beats-per-minute (bpm). Conclusions: Synchronization of list-mode acquisition with external patient monitoring devices such as those employed in motion-tracking can reliably be achieved using a simple method that can be implemented using minimal external hardware and software modification through a single input channel, while still recording cardiac gating signals.

OConnor, J. Michael; Pretorius, P. Hendrik; Johnson, Karen; King, Michael A., E-mail: Michael.King@umassmed.edu [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States)

2013-12-15T23:59:59.000Z

370

Adaptive second order sliding mode control of doubly fed induction generator in wind energy conversion system  

Science Journals Connector (OSTI)

A dynamic synchronous d-q reference frame based modeling and a novel adaptive higher order sliding mode control theory for doubly fed induction generator (DFIG) based wind energy conversion system (WECS) have been proposed in this paper. As depicted from the literature the sliding mode control strategy involving computation of converter currents introduces some inaccuracies for optimal extraction of the power references of the DFIG. On the contrary the proposed method contributes with some important features such as chatter-free performance and heftiness in terms of transient response of the non-linear systems subjected to dynamic conditions such as lower and higher wind speeds. Consequently a higher order sliding mode controller using the active and reactive power of the DFIG as controller inputs has been proposed in this paper. As compared with the other two methods the proposed higher order sliding mode power control souvenirs a significantly improved as well as stable performance of the DFIG based WECS in terms of reduced settling time as well as quickly damping out the oscillations exhibited by the system. The robustness and stability of the proposed control strategy has been validated in MATLAB environment in terms of the comparison of its performance with traditional proportional-integral and existing first-order sliding mode controller (employing converter current as input) subjected to a wide range of disturbances for sub and super synchronous mode of operation of the DFIG subjected to lower and higher wind speeds along with the available practical wind speed data as depicted in the simulation and result section.

2014-01-01T23:59:59.000Z

371

Modes of storage ring coherent instabilities  

SciTech Connect

Longitudinal impedance in a beam and various modes of longitudinal coherent instabilities are discussed. The coasting beam coherent instability, microwave instability, and single-bunch longitudinal coherent instabilities are considered. The Vlasov equation is formulated, and a method of solving it is developed. The synchrotron modes are treated, which take the possible bunch shape distortion fully into consideration. A method of treating the synchrotron mode coupling in the case of a small bunch is discussed which takes advantage of the fact that only a few of the synchrotron modes can contribute in such a case. The effect of many bunches on the coherent motion of the beam and the longitudinal symmetric coupled bunch modes are discussed. The transverse impedance is then introduced, and the transverse coasting beam instability is discussed. Various bunched beam instabilities are discussed, including both single bunch instabilities and coupled bunch instabilities. The Vlasov equation for transverse as well as longitudinal motion of particles is introduced as well as a method of solving it within a linear approximation. Head-tail modes and short bunch instabilities and strong coupling instabilities in the long bunch case are covered. (LEW)

Wang, J.M.

1986-12-01T23:59:59.000Z

372

Laser cooling with ultrafast pulse trains  

E-Print Network (OSTI)

We propose a new laser cooling method for atomic species whose level structure makes traditional laser cooling difficult. For instance, laser cooling of hydrogen requires vacuum-ultraviolet laser light, while multielectron atoms need laser light at many widely separated frequencies. These restrictions can be eased by laser cooling on two-photon transitions with ultrafast pulse trains. Laser cooling of hydrogen, antihydrogen, and carbon appears feasible, and extension of the technique to molecules may be possible.

David Kielpinski

2003-06-14T23:59:59.000Z

373

Pulsed atmospheric fluidized bed combustor apparatus  

DOE Patents (OSTI)

A pulsed atmospheric fluidized bed reactor system is disclosed and claimed along with a process for utilization of same for the combustion of, e.g. high sulfur content coal. The system affords a economical, ecologically acceptable alternative to oil and gas fired combustors. The apparatus may also be employed for endothermic reaction, combustion of waste products, e.g., organic and medical waste, drying materials, heating air, calcining and the like.

Mansour, Momtaz N. (Columbia, MD)

1993-10-26T23:59:59.000Z

374

Term Appointments | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Term Appointments Term Appointments Term Appointments A term appointment is a non-permanent time limited appointment for a period of more than 1 year but not more than 4 years. The appointment allows eiligibility for benefits and retirement coverage. Reasons for making a term appointment include but are not limited to: project work, extraordinary workload, scheduled abolishment, reorganization, uncertainty of future funding, or the need to maintain permanent positions for placement of employees who would otherwise be displaced from other parts of the organization. OPM may authorize exceptions beyond the 4-year limit when the extension is appropriately justifiable. For example, if the deadline of a major project is extended and the employee's term appointment is at the end of its time

375

The Slow Manifold of a Five-Mode Model  

Science Journals Connector (OSTI)

The slow manifold of an inviscid five-mode model introduced by Lorenz is investigated. When the influence of the gravity modes on the Rossby modes is neglected, the analytical solution given by Lorenz and Krishnamurthy is generalized. When ...

John P. Boyd

1994-04-01T23:59:59.000Z

376

D-3 FALL TERM TERM CR. COURSE DEPARTMENT  

E-Print Network (OSTI)

Community Oral Health Dr. P.N. Gregory 2 PDCH 302 Pediatric Dental Clinic* Pediatric Dentistry Dr. H.K. Sharp 1 PDCH 304 Patient Centered Dentistry Pediatric Dentistry Ms. M. Seeberg 2 PERI 301 Basic *Continues through Spring Term D-3 SPRING TERM 1 DSOM 305 Advanced Dental Radiology Oral Maxillofacial

Cui, Yan

377

D-3 FALL TERM TERM CR COURSE DEPARTMENT  

E-Print Network (OSTI)

Community Oral Health Dr. P.N. Gregory 2 PDCH 302 Pediatric Dental Clinic* Pediatric Dentistry Dr. H.K. Sharp 1 PDCH 304 Patient Centered Dentistry Pediatric Dentistry Ms. M. Seeberg 2 PERI 301 Basic *Continues through Spring Term D-3 SPRING TERM 1 DSOM 305 Advanced Dental Radiology Oral Maxillofacial

Cui, Yan

378

Microsoft Word - BPD Privacy Terms  

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

Data Privacy Terms (Updated 2014-12) Your company or organization (PROVIDER) has agreed to provide PROPRIETARY DATA regarding building energy performance to the Buildings...

379

Compressed Wannier modes found from an $L_1$ regularized energy functional  

E-Print Network (OSTI)

We propose a method for calculating Wannier functions of periodic solids directly from a modified variational principle for the energy, subject to the requirement that the Wannier functions are orthogonal to all their translations ("shift-orthogonality"). Localization is achieved by adding an $L_1$ regularization term to the energy functional. This approach results in "compressed" Wannier modes with compact support, where one parameter $\\mu$ controls the trade-off between the accuracy of the total energy and the size of the support of the Wannier modes. Efficient algorithms for shift-orthogonalization and solution of the variational minimization problem are demonstrated.

Farzin Barekat; Ke Yin; Russel E. Caflisch; Stanley J. Osher; Rongjie Lai; Vidvuds Ozolins

2014-03-26T23:59:59.000Z

380

Low-energy octupole modes in the A=2454 region  

Science Journals Connector (OSTI)

When the low-energy octupole state and low-energy octupole resonance are considered as a single composite mode in A=2454 even-even nuclei, a regular pattern for the energy centroids is found. The location of the energy centroid as a function of nuclear mass can be explained in terms of the effects of shell structure on collective octupole excitations. It is predicted that the energy of the centroid of the composite mode in the stable isotope Cr50, where it has not yet been measured, is 5.70.4 MeV.

P. D. Cottle and K. W. Kemper

1990-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

A single chip pulse processor for nuclear spectroscopy  

SciTech Connect

A high performance digital pulse processor, integrated into a single gate array microcircuit, has been developed for spaceflight applications. The new approach takes advantage of the latest CMOS high speed A/D flash converters and low-power gated logic arrays. The pulse processor measures pulse height, pulse area and the required timing information (e.g. multi detector coincidence and pulse pile-up detection). The pulse processor features high throughput rate (e.g. 0.5 Mhz for 2 usec gausssian pulses) and improved differential linearity (e.g. + or - 0.2 LSB for a + or - 1 LSB A/D). Because of the parallel digital architecture of the device, the interface is microprocessor bus compatible. A satellite flight application of this module is presented for use in the X-ray imager and high energy particle spectrometers of the PEM experiment on the Upper Atmospheric Research Satellite.

Hilsenrath, F.; Bakke, J.C.; Voss, H.D.

1985-02-01T23:59:59.000Z

382

Infrared nanosecond laser-metal ablation in atmosphere: Initial plasma during laser pulse and further expansion  

SciTech Connect

We have investigated the dynamics of the nanosecond laser ablated plasma within and after the laser pulse irradiation using fast photography. A 1064 nm, 15 ns laser beam was focused onto a target made from various materials with an energy density in the order of J/mm{sup 2} in atmosphere. The plasma dynamics during the nanosecond laser pulse were observed, which could be divided into three stages: fast expansion, division into the primary plasma and the front plasma, and stagnation. After the laser terminated, a critical moment when the primary plasma expansion transited from the shock model to the drag model was resolved, and this phenomenon could be understood in terms of interactions between the primary and the front plasmas.

Wu, Jian; Wei, Wenfu; Li, Xingwen; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)

2013-04-22T23:59:59.000Z

383

Ablation driven by hot electrons generated during the ignitor laser pulse in shock ignition  

SciTech Connect

An analytical model for the ablation driven by hot electrons is presented. The hot electrons are assumed to be generated during the high intensity laser spike used to produce the ignitor shock wave in the shock ignition driven inertial fusion concept, and to carry on the absorbed laser energy in its totality. Efficient energy coupling requires to keep the critical surface sufficiently close to the ablation front and this goal can be achieved for high laser intensities provided that the laser wavelength is short enough. Scaling laws for the ablation pressure and the other relevant magnitudes of the ablation cloud are found in terms of the laser and target parameters. The effect of the preformed plasma assembled by the compression pulse, previous to the ignitor, is also discussed. It is found that a minimum ratio between the compression and the ignitor pulses would be necessary for the adequate matching of the corresponding scale lengths.

Piriz, A. R.; Rodriguez Prieto, G. [E.T.S.I. Industriales, Universidad de Castilla-La Mancha and Instituto de Investigaciones Energeticas, 13071 Ciudad Real (Spain); Tahir, N. A. [GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany); Zhang, Y. [School of Physics and Optoelectronic Technology, Dalian University of Technology, 116024 Dalian (China); Liu, S. D.; Zhao, Y. T. [Institute of Modern Physics, Chinese Academy of Science, 730000 Lanzhou (China)

2012-12-15T23:59:59.000Z

384

Transient X-ray pulsar V0332+53: pulse phase-resolved spectroscopy and the reflection model  

E-Print Network (OSTI)

We present the results of the pulse phase- and luminosity-resolved spectroscopy of the transient X-ray pulsar V0332+53, performed for the first time in a wide luminosity range (1-40)x10^{37} erg/s during a giant outburst observed by the RXTE observatory in Dec 2004 - Feb 2005. We characterize the spectra quantitatively and built the detailed "three-dimensional" picture of spectral variations with pulse phase and throughout the outburst. We show that all spectral parameters are strongly variable with the pulse phase, and the pattern of this variability significantly changes with luminosity directly reflecting the associated changes in the structure of emission regions and their beam patterns. Obtained results are qualitatively discussed in terms of the recently developed reflection model for the formation of cyclotron lines in the spectra of X-ray pulsars.

Lutovinov, A A; Suleimanov, V F; Mushtukov, A A; Doroshenko, V; Nagirner, D I; Poutanen, J

2015-01-01T23:59:59.000Z

385

Mixed-mode diesel HCCI with External Mixture Formation: Preliminary...  

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

Mixed-mode diesel HCCI with External Mixture Formation: Preliminary Results Mixed-mode diesel HCCI with External Mixture Formation: Preliminary Results 2003 DEER Conference...

386

Modeling Combustion Control for High Power Diesel Mode Switching  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

and Emissions Research Conference 2010 Modeling Combustion Control for High Power Diesel Mode Switching P-20 Motivation * High power LTC-diesel mode operation * Transient...

387

Modeling Combustion Control for High Power Diesel Mode Switching...  

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

Combustion Control for High Power Diesel Mode Switching Modeling Combustion Control for High Power Diesel Mode Switching Poster presentation given at the 16th Directions in...

388

Unregulated Emissions from High-Efficiency Clean Combustion Modes...  

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

Unregulated Emissions from High-Efficiency Clean Combustion Modes - ORNL-FEERC Unregulated Emissions from High-Efficiency Clean Combustion Modes - ORNL-FEERC Poster presentation at...

389

Fact #636: August 16, 2010 Transportation Energy Use by Mode...  

Energy Savers (EERE)

by Mode, 2008 Bar graph showing the transportation energy use by mode (buses, rail, pipeline, water, air, mediumheavy trucks, and light vehicles) for 2008. For more detailed...

390

Analysis of electromagnetic modes excited in overmoded structure terahertz source  

SciTech Connect

A method on electromagnetic mode analysis in overmoded structure terahertz source is studied in this paper. This mode analysis method is based on Fourier-Bessel series and the particle-in-cell simulation. The result of mode analysis shows that there are TM{sub 02} and TM{sub 03} modes present in the waveguide motivated by mode change in the discontinuity. The mode content keeps stable when the device starts to work. The magnetic field and the voltage of beam do not change the mode content to some extent. The parameters of diode affect the mode content significantly.

Li, Xiaoze; Xiao, Renzhen; Wang, Guangqiang; Zhang, Lijun; Zhang, Yuchuan; Ye, Hu [Northwest Institute of Nuclear Technology, P. O. Box 69-1, Xi'an 710024 (China)] [Northwest Institute of Nuclear Technology, P. O. Box 69-1, Xi'an 710024 (China); Wang, Jianguo [Northwest Institute of Nuclear Technology, P. O. Box 69-1, Xi'an 710024 (China) [Northwest Institute of Nuclear Technology, P. O. Box 69-1, Xi'an 710024 (China); School of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an 710049 (China)

2013-08-15T23:59:59.000Z

391

Noise-like pulse based on dissipative four-wave-mixing with photonic crystal fiber filled by reduced graphene oxide  

E-Print Network (OSTI)

A noise-like pulse based on dissipative four-wave-mixing in a fiber cavity with photonic crystal fiber filled by reduced graphene oxide is proposed. Due to large evanescent field provided by 3 cm photonic crystal fiber and ultrahigh nonlinearity of reduced graphene oxide, this mixed structure provides excellent saturable absorption and high nonlinearity, which are necessary for generating four-wave-mixing (FWM). We experimentally prove that the mode-locked laser transfers its energy from center wavelength to sidebands through degenerate FWM, and new frequencies are generated via cascaded FWM among those sidebands. During this process, the frequencies located in various orders of longitudinal modes of the ring cavity are supported, and others are suppressed due to destructive interference. As the longitudinal modes of the cavity with a spacing of 6.874 MHz are partially supported, the loosely fixed phase relationship results in noise-like pulse with a coherent peak of 530 fs locating on a pedestal of 730.693 p...

Gao, Lei; Huang, Wei

2014-01-01T23:59:59.000Z

392

Radiative Decay Modes of the Muon  

Science Journals Connector (OSTI)

A 5-in. freon bubble chamber was used to search for the following decay modes of the ?+ meson: (1)?+?e++?, (2)?+?e++e-+e+, (3)?+?e++?0+?0+?, (4)?+?e++?0+?0+e++e-. Two exposures were made at the Carnegie Institute of Technology synchrocyclotron. A total of 200 000 pictures were taken yielding 3.3105 ?+ meson decays.A total of 3105 ?+ decays were examined for mode (1). No decays consistent with this mode were found. The upper limit on the branching ratio Rrad was found to be Rrad=(?+?e++?)(?+?e++?0+?0)<2.510-5.A total of 3.3105 ?+ decays were scanned for mode (2) and no such decays were observed. The limit on the branching ratio R3e was found to be R3e=(?+?e++e-+e+)(?+?e++?0+?0)<410-6.The internal bremsstrahlung rate (mode 3) was measured for two values of E?0 (the minimum photon energy detected). The results were RIB=(?+?e++?0+?0+?)(?+?e++?0+?0), RIB=(1.40.4)10-2,E?0=10Mev, RIB=(3.31.3)10-3,E?0=20Mev.The rate of internal conversion of internal bremsstrahlung [mode (4)] was found to be RIC=(?+?e++?0+?0+e++e-)(?+?e++?0+?0)=(2.21.5)10-5,E0=10Mev, where E0 is the minimum energy of the internally converted ? ray.A summary is given of previous experiments on these decay modes and results are discussed with special reference to the intermediate boson scheme of weak four-fermion interactions.

R. R. Crittenden; W. D. Walker; J. Ballam

1961-03-15T23:59:59.000Z

393

Effects of carbon nanotubes and graphene oxide absorbers on the noise of mode-locked fiber lasers  

E-Print Network (OSTI)

Phase noise is very important for the ultrafast pulse application in telecommunication, ultrafast diagnose, material science, and biology. In this paper, two types of carbon nano-materials, single-wall carbon nanotube and graphene oxide, are investigated for noise suppression in ultrafast photonics. Various properties of the wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the phase noise of the ultrafast pulses. A reduced-noise femtosecond fiber laser is experimentally demonstrated by optimizing the above parameters of carbon material based SAs. The phase noise reduction more than 10 dB at 10 kHz can be obtained in the experiments. To our knowledge, this is the first time that the relationship between different carbon material based SAs and the phase noise of mode-locked lasers has been investigated. This work will pave the way to get a high-quality ultrashort pulse in passively mode-locked fiber lasers.

Li, Xiaohui; Yu, Xuechao; Wang, Yonggang; Wang, Yishan; Meng, Bo; Tang, Yulong; Yu, Xia; Zhang, Ying; Sun, Zhipei; Shum, Perry Ping; Wang, Qi Jie

2014-01-01T23:59:59.000Z

394

Detachment-induced electron production in the early afterglow of pulsed cc-rf oxygen plasmas  

SciTech Connect

Line integrated electron densities are measured by 160.28 GHz Gaussian beam microwave interferometry in a 10 Hz pulsed (50% duty cycle) cc-rf oxygen discharge, operating at 13.56 MHz. Depending on the processing parameters, the oxygen rf discharge displays two different operation modes regarding its electronegativity. For higher rf power with negative self-bias voltage above -220 V, the oxygen discharge acts as electropositive plasma (n{sub -}/n{sub e} Much-Less-Than 1), whereas at lower rf power and self-bias voltage the plasma becomes strongly electronegative (n{sub -}/n{sub e}>2). In the latter mode, a significant electron density increase is measured in the early afterglow (<100 {mu}s) within a pressure range from 20 to 100 Pa. By use of a simple rate equation model, the temporal behavior of the electron density could be reproduced for both modes of electronegativity. The electron production in the early afterglow is mainly caused due to the detachment of negative atomic oxygen ions by metastable oxygen molecules.

Kuellig, C.; Dittmann, K.; Meichsner, J. [University of Greifswald, Institute of Physics, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany)

2012-07-15T23:59:59.000Z

395

Shortterm solar effects  

Science Journals Connector (OSTI)

...J. L. Culhane and J. C. R. Hunt Short-term solar effects Richard A. Harrison Space Science and Technology...OX11 0QX, UK Short-term transient events in the solar atmosphere, namely solar flares and coronal mass ejections, can have a direct...

2003-01-01T23:59:59.000Z

396

Long-Term Environmental Stewardship  

NLE Websites -- All DOE Office Websites (Extended Search)

Long-Term Environmental Stewardship Long-Term Environmental Stewardship The Long-Term Environmental Stewardship Program ensures protection of human health and the environment, following site remediations. Contact Environmental Communication & Public Involvement P.O. Box 1663 MS M996 Los Alamos, NM 87545 (505) 667-0216 Email Continuing environmental commitment Long-term stewardship activities are designed to prevent exposures to residual contamination and waste including groundwater monitoring ongoing pump-and-treatment activities maintenance of barriers and other contaminant structures periodic inspections control of site access posted signs Long-term environmental stewardship (LTES) data access DOE requires that data used to make decisions concerning LTES conditions be readily accessible to the public. To accomplish this, sample analysis data

397

A Non-radial Oscillation Mode in an Accreting Millisecond Pulsar?  

Science Journals Connector (OSTI)

We present results of targeted searches for signatures of non-radial oscillation modes (such as r- and g-modes) in neutron stars using RXTE data from several accreting millisecond X-ray pulsars (AMXPs). We search for potentially coherent signals in the neutron star rest frame by first removing the phase delays associated with the star's binary motion and computing fast Fourier transform power spectra of continuous light curves with up to 230 time bins. We search a range of frequencies in which both r- and g-modes are theoretically expected to reside. Using data from the discovery outburst of the 435Hz pulsar XTE J1751305 we find a single candidate, coherent oscillation with a frequency of 0.5727597 ? ?spin = 249.332609Hz, and a fractional Fourier amplitude of 7.46 ? 104. We estimate the significance of this feature at the 1.6 ? 103 level, slightly better than a 3? detection. Based on the observed frequency we argue that possible mode identifications include rotationally modified g-modes associated with either a helium-rich surface layer or a density discontinuity due to electron captures on hydrogen in the accreted ocean. In the latter case the presence of sufficient hydrogen in this ultracompact system with a likely helium-rich donor would present an interesting puzzle. Alternatively, the frequency could be identified with that of an inertial mode or a core r-mode modified by the presence of a solid crust; however, the r-mode amplitude required to account for the observed modulation amplitude would induce a large spin-down rate inconsistent with the observed pulse timing measurements. For the AMXPs XTE J1814338 and NGC6440 X2 we do not find any candidate oscillation signals, and we place upper limits on the fractional Fourier amplitude of any coherent oscillations in our frequency search range of 7.8 ? 104 and 5.6 ? 103, respectively. We briefly discuss the prospects and sensitivity for similar searches with future, larger X-ray collecting area missions.

Tod Strohmayer; Simin Mahmoodifar

2014-01-01T23:59:59.000Z

398

Spatiotemporal reconstruction of list-mode PET data  

SciTech Connect

We describe a method for computing a continuous time estimate of tracer density using list-mode positron emission tomography data. The rate function in each voxel is modeled as an inhomogeneous Poisson process whose rate function can be represented using a cubic B-spline basis. The rate functions are estimated by maximizing the likelihood of the arrival times of detected photon pairs over the control vertices of the spline, modified by quadratic spatial and temporal smoothness penalties and a penalty term to enforce nonnegativity. Randoms rate functions are estimated by assuming independence between the spatial and temporal randoms distributions. Similarly, scatter rate functions are estimated by assuming spatiotemporal independence and that the temporal distribution of the scatter is proportional to the temporal distribution of the trues. A quantitative evaluation was performed using simulated data and the method is also demonstrated in a human study using 11C-raclopride.

Nichols, Thomas E.; Qi, Jinyi; Asma, Evren; Leahy, Richard M.

2002-03-01T23:59:59.000Z

399

Generation of high power pulsed terahertz radiation using a plasmonic photoconductive emitter array with logarithmic spiral antennas  

SciTech Connect

An array of 3??3 plasmonic photoconductive terahertz emitters with logarithmic spiral antennas is fabricated on a low temperature (LT) grown GaAs substrate and characterized in response to a 200 fs optical pump from a Ti:sapphire mode-locked laser at 800?nm wavelength. A microlens array is used to split and focus the optical pump beam onto the active area of each plasmonic photoconductive emitter element. Pulsed terahertz radiation with record high power levels up to 1.9 mW in the 0.12 THz frequency range is measured at an optical pump power of 320 mW. The record high power pulsed terahertz radiation is enabled by the use of plasmonic contact electrodes, enhancing the photoconductor quantum efficiencies, and by increasing the overall device active area, mitigating the carrier screening effect and thermal breakdown at high optical pump power levels.

Berry, Christopher W. [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Hashemi, Mohammad R.; Jarrahi, Mona [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States)

2014-02-24T23:59:59.000Z

400

Single transverse mode selectively oxidized vertical cavity lasers  

SciTech Connect

Vertical cavity surface emitting lasers (VCSELs) which operate in multiple transverse optical modes have been rapidly adopted into present data communication applications which rely on multi-mode optical fiber. However, operation only in the fundamental mode is required for free space interconnects and numerous other emerging VCSEL applications. Two device design strategies for obtaining single mode lasing in VCSELs based on mode selective loss or mode selective gain are reviewed and compared. Mode discrimination is attained with the use of a thick tapered oxide aperture positioned at a longitudinal field null. Mode selective gain is achieved by defining a gain aperture within the VCSEL active region to preferentially support the fundamental mode. VCSELs which exhibit greater than 3 mW of single mode output power at 850 nm with mode suppression ratio greater than 30 dB are reported.

CHOQUETTE,KENT D.; GEIB,KENT M.; BRIGGS,RONALD D.; ALLERMAN,ANDREW A.; HINDI,JANA JO

2000-04-26T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Benchmarking kinetic calculations of resistive wall mode stability  

SciTech Connect

Validating the calculations of kinetic resistive wall mode (RWM) stability is important for confidently predicting RWM stable operating regions in ITER and other high performance tokamaks for disruption avoidance. Benchmarking the calculations of the Magnetohydrodynamic Resistive SpectrumKinetic (MARS-K) [Y. Liu et al., Phys. Plasmas 15, 112503 (2008)], Modification to Ideal Stability by Kinetic effects (MISK) [B. Hu et al., Phys. Plasmas 12, 057301 (2005)], and Perturbed Equilibrium Nonambipolar Transport (PENT) [N. Logan et al., Phys. Plasmas 20, 122507 (2013)] codes for two Solov'ev analytical equilibria and a projected ITER equilibrium has demonstrated good agreement between the codes. The important particle frequencies, the frequency resonance energy integral in which they are used, the marginally stable eigenfunctions, perturbed Lagrangians, and fluid growth rates are all generally consistent between the codes. The most important kinetic effect at low rotation is the resonance between the mode rotation and the trapped thermal particle's precession drift, and MARS-K, MISK, and PENT show good agreement in this term. The different ways the rational surface contribution was treated historically in the codes is identified as a source of disagreement in the bounce and transit resonance terms at higher plasma rotation. Calculations from all of the codes support the present understanding that RWM stability can be increased by kinetic effects at low rotation through precession drift resonance and at high rotation by bounce and transit resonances, while intermediate rotation can remain susceptible to instability. The applicability of benchmarked kinetic stability calculations to experimental results is demonstrated by the prediction of MISK calculations of near marginal growth rates for experimental marginal stability points from the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)].

Berkery, J. W.; Sabbagh, S. A. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)] [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States); Liu, Y. Q. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)] [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Wang, Z. R.; Logan, N. C.; Park, J.-K.; Manickam, J. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Betti, R. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)] [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

2014-05-15T23:59:59.000Z

402

2007 Raj JainCSE571SWashington University in St. Louis Modes ofModes of  

E-Print Network (OSTI)

, CFB, CTR 2. Privacy+Integrity 3. DES Attacks 4. 3DES and its design Ref: Chapter 4 of textbook. #12. Electronic Code Book (ECB) 2. Cipher Block Chaining (CBC) 3. Cipher Feedback Mode (CFB) 4. Output Feedback be used #12;6-10 ©2007 Raj JainCSE571SWashington University in St. Louis kk--Bit Cipher Feedback Mode (CFB

Jain, Raj

403

Detecting individual gravity modes in the Sun  

E-Print Network (OSTI)

Many questions are still open regarding the structure and the dynamics of the solar core. By constraining more this region in the solar evolution models, we can reduce the incertitudes on some physical processes and on momentum transport mechanisms. A first big step was made with the detection of the signature of the dipole-gravity modes in the Sun, giving a hint of a faster rotation rate inside the core. A deeper analysis of the GOLF/SoHO data unveils the presence of a pattern of peaks that could be interpreted as dipole gravity modes. In that case, those modes can be characterized, thus bringing better constraints on the rotation of the core as well as some structural parameters such as the density at these very deep layers of the Sun interior.

Garcia, R A; Eff-Darwich, A; Garrido, R; Jimenez, A; Mathis, S; Moya, A; Palle, P L; Regulo, C; Salabert, D; Suarez, J C; Turck-Chieze, S

2009-01-01T23:59:59.000Z

404

Contained Modes In Mirrors With Sheared Rotation  

SciTech Connect

In mirrors with E B rotation, a fixed azimuthal perturbation in the lab frame can appear as a wave in the rotating frame. If the rotation frequency varies with radius, the plasma-frame wave frequency will also vary radially due to the Doppler shift. A wave that propagates in the high rotation plasma region might therefore be evanescent at the plasma edge. This can lead to radially localized Alfven eigenmodes with high azimuthal mode numbers. Contained Alfven modes are found both for peaked and non-peaked rotation profiles. These modes might be useful for alpha channeling or ion heating, as the high azimuthal wave number allows the plasma wave frequency in the rotating frame to exceed the ion cyclotron frequency. __________________________________________________

Abraham J. Fetterman and Nathaniel J. Fisch

2010-10-08T23:59:59.000Z

405

Do I like my ICON? Determining preferences for firms' mode of strategic focus  

Science Journals Connector (OSTI)

Whether they intend to or not, firms adopt a strategic mode of focus, a way of directing efforts towards markets, products, both or neither. However, in a fast changing environment, such as South Africa, little information exists on whether managers within these organisations feel that the archetype they have adopted will be appropriate for survival in the near mid-term future. This paper reports on the results of a study that identified the modes of focus of South African firms as perceived by senior marketing managers. It then matches these to the strategic mode that the managers see as most likely to guarantee the future success of their firms. Limitations of the study are identified, implications for management highlighted and avenues for future research discussed.

Leyland F. Pitt; Pierre Berthon; Melani Prinsloo; Deon Nel

2007-01-01T23:59:59.000Z

406

Optimal signal recovery for pulsed balanced detection  

Science Journals Connector (OSTI)

We demonstrate a tool for filtering technical and electronic noises from pulses of light, especially relevant for signal processing methods in quantum optics experiments as a means to achieve the shot-noise level and reduce strong technical noise by means of a pattern function. We provide the theory of this pattern-function filtering based on balance detection. Moreover, we implement an experimental demonstration where 10 dB of technical noise is filtered after balance detection. Such filter can readily be used for probing magnetic atomic ensembles in environments with strong technical noise.

Yannick A. de Icaza Astiz; Vito Giovanni Lucivero; R. de J. Len-Montiel; Morgan W. Mitchell

2014-09-10T23:59:59.000Z

407

Stabilization of Ballooning Modes by Nonparaxial Cells  

SciTech Connect

An analysis is made of the effect of high-curvature stabilizing nonparaxial elements (cells) on the MHD plasma stability in open confinement systems and in confinement systems with closed magnetic field lines. It is shown that the population of particles trapped in such cells has a stabilizing effect not only on convective (flute) modes but also on ballooning modes, which govern the maximum possible {beta} value. In the kinetic approach, which distinguishes between the effects of trapped and passing particles, the maximum possible {beta} values consistent with stability can be much higher than those predicted by the MHD model.

Arsenin, V.V.; Zvonkov, A.V.; Skovoroda, A.A. [Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, pl. Kurchatova 1, Moscow, 123182 (Russian Federation)

2005-01-15T23:59:59.000Z

408

Self-Similar Modes of Coherent Diffusion  

E-Print Network (OSTI)

Self-similar solutions of the coherent diffusion equation are derived and measured. The set of real similarity solutions is generalized by the introduction of a nonuniform phase surface, based on the elegant Gaussian modes of optical diffraction. In an experiment of light storage in a gas of diffusing atoms, a complex initial condition is imprinted, and its diffusion dynamics is monitored. The self-similarity of both the amplitude and the phase pattern is demonstrated, and an algebraic decay associated with the mode order is measured. Notably, as opposed to a regular diffusion spreading, a self-similar contraction of a special subset of the solutions is predicted and observed.

O. Firstenberg; P. London; D. Yankelev; R. Pugatch; M. Shuker; N. Davidson

2010-08-16T23:59:59.000Z

409

Nonlinear mode coupling analysis in the Tevatron  

SciTech Connect

Increased demand for higher luminosities from Fermilab proton-antiproton collider requires higher intensities and increased number of bunches. The performance of existing 6 x 6 and the proposed 36 x 36 collider is often limited by the non-linear effects arising from beam-beam interactions, in particular for high intensity beams. The tune shifts and spread from increased long range interactions combined with higher order multipoles complicates the frequency spectrum of the particle motions. TEAPOT simulation program is used to generate turn by turn data that could be used in the nonlinear mode spectrums analysis. Bispectral mode analysis is discussed.

Assadi, S.; Mishra, C.S.

1995-08-01T23:59:59.000Z

410

Single molecule imaging with longer x-ray laser pulses  

E-Print Network (OSTI)

In serial femtosecond crystallography, x-ray laser pulses do not need to outrun all radiation damage processes because Bragg diffraction exceeds the damage-induced background scattering for longer pulses ($\\sim$ 50--100 fs). This is due to a "self-gating pulse" effect whereby damage terminates Bragg diffraction prior to the pulse completing its passage through the sample, as if that diffraction were produced by a shorter pulse of equal fluence. We show here that a similar gating effect applies to single molecule diffraction with respect to spatially uncorrelated damage processes like ionization and ion diffusion. The effect is clearly seen in calculations of the diffraction contrast, by calculating the diffraction of average structure separately to the diffraction from statistical fluctuations of the structure due to damage ("damage noise"). Our results suggest that sub-nanometer single molecule imaging with longer pulses, like those produced at currently operating facilities, should not yet be ruled out. The...

Martin, Andrew V; Caleman, Carl; Quiney, Harry M

2015-01-01T23:59:59.000Z

411

Evolution of fast magnetoacoustic pulses in randomly structured coronal plasmas  

E-Print Network (OSTI)

Magnetohydrodynamic waves interact with structured plasmas and reveal the internal magnetic and thermal structures therein, thereby having seismological applications in the solar atmosphere. We investigate the evolution of fast magnetoacoustic pulses in randomly structured plasmas, in the context of large-scale propagating waves in the solar atmosphere. We perform one dimensional numerical simulations of fast wave pulses propagating perpendicular to a constant magnetic field in a low-$\\beta$ plasma with a random density profile across the field. Both linear and nonlinear regimes are considered. We study how the evolution of the pulse amplitude and width depends on their initial values and the parameters of the random structuring. A randomly structured plasma acts as a dispersive medium for a fast magnetoacoustic pulse, causing amplitude attenuation and broadening of the pulse width. After the passage of the main pulse, secondary propagating and standing fast waves appear in the plasma. Width evolution of both...

Yuan, D; Nakariakov, V M; Li, B; Keppens, R

2014-01-01T23:59:59.000Z

412

Method of estimating pulse response using an impedance spectrum  

DOE Patents (OSTI)

Electrochemical Impedance Spectrum data are used to predict pulse performance of an energy storage device. The impedance spectrum may be obtained in-situ. A simulation waveform includes a pulse wave with a period greater than or equal to the lowest frequency used in the impedance measurement. Fourier series coefficients of the pulse train can be obtained. The number of harmonic constituents in the Fourier series are selected so as to appropriately resolve the response, but the maximum frequency should be less than or equal to the highest frequency used in the impedance measurement. Using a current pulse as an example, the Fourier coefficients of the pulse are multiplied by the impedance spectrum at corresponding frequencies to obtain Fourier coefficients of the voltage response to the desired pulse. The Fourier coefficients of the response are then summed and reassembled to obtain the overall time domain estimate of the voltage using the Fourier series analysis.

Morrison, John L; Morrison, William H; Christophersen, Jon P; Motloch, Chester G

2014-10-21T23:59:59.000Z

413

Method and apparatus for ultrasonic doppler velocimetry using speed of sound and reflection mode pulsed wideband doppler  

DOE Patents (OSTI)

According to the present invention, a method and apparatus rely upon tomographic measurement of the speed of sound and fluid velocity in a pipe. The invention provides a more accurate profile of velocity within flow fields where the speed of sound varies within the cross-section of the pipe. This profile is obtained by reconstruction of the velocity profile from the local speed of sound measurement simultaneously with the flow velocity. The method of the present invention is real-time tomographic ultrasonic Doppler velocimetry utilizing a to plurality of ultrasonic transmission and reflection measurements along two orthogonal sets of parallel acoustic lines-of-sight. The fluid velocity profile and the acoustic velocity profile are determined by iteration between determining a fluid velocity profile and measuring local acoustic velocity until convergence is reached.

Shekarriz, Alireza (Kennewick, WA); Sheen, David M. (Richland, WA)

2000-01-01T23:59:59.000Z

414

Modes of Operation: Der Cipher Feedback Steffen Reith  

E-Print Network (OSTI)

Modes of Operation: Der Cipher Feedback Mode (CFB) Steffen Reith 7. Mai 2005 Der CFB-Mode wird Shiftr Bits Shift ic r Bitsr Bits rn n r n n r r Der CFB-Mode 1 Dies ist mit Hilfe der Abbildung leicht

Vollmer, Heribert

415

Head-Tail Modes for Strong Space Charge  

SciTech Connect

Head-tail modes are described here for the space charge tune shift significantly exceeding the synchrotron tune. General equation for the modes is derived. Spatial shapes of the modes, their frequencies, and coherent growth rates are explored. The Landau damping rates are also found. Suppression of the transverse mode coupling instability by the space charge is explained.

Burov, Alexey

2008-12-01T23:59:59.000Z

416

Observation of picosecond superfluorescent pulses in rubidium atomic vapor pumped by 100-fs laser pulses  

E-Print Network (OSTI)

We study the superfluorescence (SF) from a gas of rubidium atoms. The atoms of a dense vapor are excited to the 5D state from the 5S state by a two-photon process driven by 100-fs laser pulses. The atoms decay to the 6P state and then to the 5S...

Ariunbold, Gombojav O.; Kash, Michael M.; Sautenkov, Vladimir A.; Li, Hebin; Rostovtsev, Yuri V.; Welch, George R.; Scully, Marlan O.

2010-01-01T23:59:59.000Z

417

Subsidiary-absorption spin-wave-instability processes in yttrium iron garnet thin films: Coupled lateral standing modes, critical modes, and the kink effect  

Science Journals Connector (OSTI)

Subsidiary-absorption butterfly curves of the spin-wave-instability threshold microwave-field-amplitude versus static field H, for an in-plane magnetized 1.1 mm 2.0 mm, 7-?m-thick yttrium iron garnet film rectangle at 9.4 GHz, and with the linearly polarized microwave field perpendicular to the static field H and also in-plane, are found to show significant changes when H is changed from along the long edge to along the short edge of the rectangle. This effect is explained by a theory for the first-order spin-wave-instability threshold in magnetic films, which takes into acocunt the coupled standing spin-wave modes across the lateral dimensions of the film. This theory is a modification of a previous theory, which considered the standing modes across the film cross section only. The theory is able to reproduce the orientation effect found experimentally and give good fits to the butterfly-curve data. In contrast with previous results, it is not necessary to introduce ad hoc spin-wave angle ?K terms into the spin-wave linewidth to obtain these fits. The theory also yields critical-mode wave numbers in the kink region which are in the 5104 cm-1 range, which agree with previous fine-structure and Brillouin light-scattering measurements. A key parameter in the analysis is a mode spacing parameter ??K, which contains a factor of the form sin(2?K)/K, where K is the mode wave number and ?K is the mode in-plane angle relative to H. These dependences are the key to the match with experiment. They are also general, and not limited to the thin-film geometry.

G. Wiese; P. Kabos; C. E. Patton

1995-06-01T23:59:59.000Z

418

Localisation of light and spectral broadening of femtosecond laser pulses in a fibre with a minimal-microstructure cladding  

SciTech Connect

Microstructure optical fibres with a cladding consisting of a single cycle of air holes and the minimum core diameter of 1 {mu}m have been fabricated and studied. Guided modes supported by this fibre are characterised by a high light localisation degree and display the C{sub 6{nu}} point-group spatial symmetry of the transverse field distribution. A high refractive index step between the core and the cladding in the created fibres strongly confines the light field in the fibre core. The spectral broadening of low-power femtosecond laser pulses in the fibre of this type is experimentally studied. (nonlinear optical phenomena)

Zheltikov, Aleksei M [Department of Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation); Zhou, Ping; Temnov, V V; Tarasevitch, A P; Linde, D von der [Institut fur Laser- und Plasmaphysik, Universitat Essen, Essen (Germany); Kondrat'ev, Yu N; Shevandin, V S; Dukel'skii, K V; Khokhlov, A V [All-Russian Scientific Centre 'S.I. Vavilov State Optical Institute', St Petersburg (Russian Federation); Bagayev, S N [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Smirnov, Valerii B [Russian Center of Laser Physics, St. Petersburg State University, St. Petersburg (Russian Federation)

2002-06-30T23:59:59.000Z

419

Short-Term Energy Outlook  

U.S. Energy Information Administration (EIA) Indexed Site

Chart Gallery for February 2015 Short-Term Energy Outlook U.S. Energy Information Administration Independent Statistics & Analysis 0 20 40 60 80 100 120 140 160 180 200 220 Jan...

420

Device For Trapping Laser Pulses In An Optical Delay Line  

DOE Patents (OSTI)

A device for maintaining a high-energy laser pulse within a recirculating optical delay line for a period time to optimize the interaction of the pulse with an electron beam pulse train comprising closely spaced electron micropulses. The delay line allows a single optical pulse to interact with many of the electron micropulses in a single electron beam macropulse in sequence and for the introduction of additional optical pulses to interact with the micropulses of additional electron beam macropulses. The device comprises a polarization-sensitive beam splitter for admitting an optical pulse to and ejecting it from the delay line according to its polarization state, a Pockels cell to control the polarization of the pulse within the delay line for the purpose of maintaining it within the delay line or ejecting it from the delay line, a pair of focusing mirrors positioned so that a collimated incoming optical pulse is focused by one of them to a focal point where the pulse interacts with the electron beam and then afterwards the pulse is recollimated by the second focusing mirror, and a timing device which synchronizes the introduction of the laser pulse into the optical delay line with the arrival of the electron macropulse at the delay line to ensure the interaction of the laser pulse with a prescribed number of electron micropulses in sequence. In a first embodiment of the invention, the principal optical elements are mounted with their axes collinear. In a second embodiment, all principal optical elements are mounted in the configuration of a ring.

Yu, David U. L. (Rancho Palos Verdes, CA); Bullock, Donald L. (Los Angeles, CA)

1997-12-23T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Pulse Transformer Design for Magnet Powering in Particle Accelerators  

E-Print Network (OSTI)

This paper presents an optimal design procedure for pulse transformers fed by power converters for supplying pulsed current magnets in particle accelerators. Usually their volume must be minimized because of limited space available in the accelerator tunnel. Analytical and numerical models are presented as well as an experimental validation and a real case study where the design tool is exploited to derive a wide variety of solutions depending on the pulse transformers location with respect to the magnet position.

Aguglia, D

2014-01-01T23:59:59.000Z

422

Spatial and spectral effects in subcritical system pulsed experiments  

SciTech Connect

Accurate neutronic models are needed for the interpretation of pulsed experiments in subcritical systems. In this work, the extent of spatial and spectral effects in the pulse propagation phenomena is investigated and the analysis is applied to the GUINEVERE experiment. The multigroup cross section data is generated by the Monte Carlo SERPENT code and the neutronic evolution following the source pulse is simulated by a kinetic diffusion code. The results presented show that important spatial and spectral aspects need to be properly accounted for and that a detailed energy approach may be needed to adequately capture the physical features of the system to the pulse injection. (authors)

Dulla, S.; Nervo, M.; Ravetto, P. [Politecnico di Torino, Dipartimento Energia, Corso Duca degli Abruzzi, 24, 10129 Torino (Italy); Carta, M. [ENEA - C.R. CASACCIA, UTFISSM-PRONOC, Via Anguillarese, 301, 00123 S. Maria di Galeria (Italy)

2013-07-01T23:59:59.000Z

423

Transient heat transfer properties in a pulse detonation combustor .  

E-Print Network (OSTI)

??The heat transfer along the axis of a pulse detonation combustor has been characterized for various frequencies and fill fractions at 2.5 atmospheres of pressure (more)

Fontenot, Dion G.

2011-01-01T23:59:59.000Z

424

Investigation of transient plasma ignition for a Pulse Detonation Engine .  

E-Print Network (OSTI)

??Elimination or reduction of auxiliary oxygen use in Pulse Detonation Engines (PDEs) is necessary if the technology is to compete with existing Ramjet systems. This (more)

Rodriguez, Joel.

2005-01-01T23:59:59.000Z

425

Original articles: Intelligent multichannel sensors for pulse wave analysis  

Science Journals Connector (OSTI)

Aortic pulse wave velocity is an independent predictive indicator for all cause mortality and cardiovascular morbidity. Unfortunately it is only invasively accessible and thus the A. carotis-A. femoralis pulse wave velocity (cfPWV) is recommended as ... Keywords: Arterial stiffness, BP, Cardiovascular risk, ECG, Electrocardiography, FIR, ICA, INA, Idxao, Idxo, Idxs, LED, PTT, PW, PWV, Pulse transit time, Pulse wave velocity, SD, cfPWV, dBP, p'(Idxo), p'(Idxs), p(Idxo), p(Idxs), sBP

S. Rosenkranz; C. Mayer; J. Kropf; S. Wassertheurer

2011-11-01T23:59:59.000Z

426

Pulsed Laser Ignition Thresholds of Energetic Multilayer Foils  

Science Journals Connector (OSTI)

Ignition thresholds for energetic multilayer foils comprised of aluminum (Al) and platinum (Pt) layers are presented as a function of foil properties for laser pulse durations of 100...

McDonald, Joel P; Picard, Yoosuf N; Yalisove, Steven M; Adams, David P

427

Saturable inductor and transformer structures for magnetic pulse compression  

DOE Patents (OSTI)

Saturable inductor and transformer for magnetic compression of an electronic pulse, using a continuous electrical conductor looped several times around a tightly packed core of saturable inductor material.

Birx, Daniel L. (Londonderry, NH); Reginato, Louis L. (Orinda, CA)

1990-01-01T23:59:59.000Z

428

A modified parallel HVDC convertor for 24 pulse operation  

SciTech Connect

A new concept of convertor design is proposed suitable for large current ratings, such as used in back-to-back HVDC interconnections. It consists of a parallel 12-pulse configuration involving two phase shifted bridges and a thyristor-tapped interphase reactor. The dc. ripple present across the interphase reactor is used to derive a current waveform which, when added to the original phase currents, effectively doubles the converters pulse number. It is shown theoretically and experimentally that the use of dc.-ripple reinjection achieves 24-pulse operations from a conventional 12-pulse HVDC converter configuration.

Arrillaga, J.; Villablanca, M. (Canterbury Univ., Christchurch (New Zealand))

1991-01-01T23:59:59.000Z

429

Mode testing via the excess mass estimate  

Science Journals Connector (OSTI)

......right when b i = w i + 1. For the new combined mode rede fi ne the quantities a i and b i as in (A1) except that we...outer bracketing minimisers ' in place of w i and w i + 1. Then rede fi ne E i as E i = P b i a i { f (x) ? l i } + dx, where......

N. I. Fisher; J. S. Marron

2001-06-01T23:59:59.000Z

430

Do red giants have short mode lifetimes?  

E-Print Network (OSTI)

We show evidence that the red giant star ksi Hya has an oscillation mode lifetime, tau, of about 2 days significantly shorter than predicted by theory (tau = 17 days, Houdek & Gough 2002). If this is a general trend of red giants it would limit the prospects of asteroseismology on these stars because of poor coherence of the oscillations.

D. Stello; H. Kjeldsen; T. R. Bedding; D. Buzasi

2005-10-18T23:59:59.000Z

431

Thermionic converter in load-switching mode  

SciTech Connect

An electrical equivalent circuit is proposed for a thermionic electrogenerating element. It is suitable for calculation of transients in load-switching mode. Formulas are given for estimating circuit parameters. A sample numerical calculation is given for the transient between no-load and short-circuit regimes. The results may be employed to identify experimental data in the frequency domain.

Mendel'baum, M.A.; Es'kov, V.D.

1983-01-01T23:59:59.000Z

432

HYDROGEN LOCAL VIBRATIONAL MODES IN COMPOUND SEMICONDUCTORS  

E-Print Network (OSTI)

HYDROGEN LOCAL VIBRATIONAL MODES IN COMPOUND SEMICONDUCTORS M.D. MCCLUSKEY* University) spectroscopy of hydrogen and deuterium in GaP, AlSb, ZnSe, and GaN has provided important information about the structures of dopant- hydrogen complexes and their interaction with the host lattice. In GaN:Mg, for example

McCluskey, Matthew

433

Triangular-profile single-mode fiber  

Science Journals Connector (OSTI)

A low-loss triangular-profile single-mode fiber is reported. The fiber loss at 1.31.55-?m wavelengths is below 0.4 dB/km, and its zero-chromatic-dispersion wavelength is 1.402 ?m.

Saifi, M A; Cohen, L G; Stone, J; Jang, S J

1982-01-01T23:59:59.000Z

434

Two-gigawatt burst-mode operation of the intense microwave prototype (IMP) free-electron laser (FEL) for the microwave tokamak experiment (MTX)  

SciTech Connect

The MTX explored the plasma heating effects of 140 GHz microwaves from both Gyrotrons and from the IMP FEL wiggler. The Gyrotron was long pulse length (0.5 seconds maximum) and the FEL produced short-pulse length, high-peak power, single and burst modes of 140 GHZ microwaves. Full-power operations of the IMP FEL wiggler were commenced in April of 1992 and continued into October of 1992. The Experimental Test Accelerator H (ETA-II) provided a 50-nanosecond, 6-MeV, 2--3 kAmp electron beam that was introduced co-linear into the IMP FEL with a 140 GHz Gyrotron master oscillator (MO). The FEL was able to amplify the MO signal from approximately 7 kW to peaks consistently in the range of 1--2 GW. This microwave pulse was transmitted into the MTX and allowed the exploration of the linear and non-linear effects of short pulse, intense power in the MTX plasma. Single pulses were used to explore and gain operating experience in the parameter space of the IMP FEL, and finally evaluate transmission and absorption in the MTX. Single-pulse operations were repeatable. After the MTX was shut down burst-mode operations were successful at 2 kHz. This paper will describe the IMP FEL, Microwave Transmission System to MTX, the diagnostics used for calorimetric measurements, and the operations of the entire Microwave system. A discussion of correlated and uncorrelated errors that affect FEL performance will be made Linear and non-linear absorption data of the microwaves in the MTX plasma will be presented.

Felker, B.; Allen, S.; Bell, H. [and others

1993-10-06T23:59:59.000Z

435

The effect of applied electric field on pulsed radio frequency and pulsed direct current plasma jet array  

SciTech Connect

Here we compare the plasma plume propagation characteristics of a 3-channel pulsed RF plasma jet array and those of the same device operated by a pulsed dc source. For the pulsed-RF jet array, numerous long life time ions and metastables accumulated in the plasma channel make the plasma plume respond quickly to applied electric field. Its structure similar as 'plasma bullet' is an anode glow indeed. For the pulsed dc plasma jet array, the strong electric field in the vicinity of the tube is the reason for the growing plasma bullet in the launching period. The repulsive forces between the growing plasma bullets result in the divergence of the pulsed dc plasma jet array. Finally, the comparison of 309 nm and 777 nm emissions between these two jet arrays suggests the high chemical activity of pulsed RF plasma jet array.

Hu, J. T.; Liu, X. Y.; Liu, J. H.; Xiong, Z. L.; Liu, D. W.; Lu, X. P. [National State Key Lab of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, WuHan, Hubei 430074 (China); Iza, F.; Kong, M. G. [Department of Electronic and Electrical Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom)

2012-06-15T23:59:59.000Z

436

Generation of zonal flows by ion-temperature-gradient and related modes in the presence of neoclassical viscosity  

SciTech Connect

Generation of zonal flows by primary waves that are more complex than those considered in the standard drift-wave model is studied. The effects of parallel ion velocity and ion perturbed temperature and the part of the nonlinear mode interaction proportional to the ion pressure are taken into account. This generalization of the standard model allows the analysis of generation of zonal flows by a rather wide variety of primary modes, including ion temperature gradients, ion sound, electron drift, and drift-sound modes. All the listed effects, which are present in the slab geometry model, are complemented by effects of neoclassical viscosity inherent to toroidal geometry. We show that the electrostatic potential of secondary small-scale modes is expressed in terms of a nonlinear shift of the mode frequency and interpret this shift in terms of the perpendicular and parallel Doppler, nonlinear Kelvin-Helmholtz (KH), and nonlinear ion-pressure-gradient effects. A basic assumption of our model is that the primary modes form a nondispersive monochromatic wave packet. The analysis of zonal-flow generation is performed following an approach similar to that of convective-cell theory. Neoclassical zonal-flow instabilities are separated into fast and slow ones, and these are divided into two varieties. The first of them is independent of the nonlinear KH effect, while the second one is sensitive to it.

Mikhailovskii, A.B.; Smolyakov, A.I.; Kovalishen, E.A.; Shirokov, M.S.; Tsypin, V.S.; Galvao, R.M.O. [Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation) and Nonlinear Physics Laboratory, Moscow Institute of Physics and Technology, Institutskii per. 9, Dolgoprudnyi 141700, Moscow Region (Russian Federation); University of Saskatchewan, 116 Science Place, Saskatoon, S7N 5E2 (Canada) and Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation); Nonlinear Physics Laboratory, Moscow Institute of Physics and Technology, Institutskii per. 9, Dolgoprudnyi 141700, Moscow Region (Russian Federation) and Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation); Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation) and Moscow Engineering Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Physics Institute, University of Sao Paulo, Cidade Universitaria, 05508-900 Sao Paulo (Brazil); Physics Institute, University of Sao Paulo, Cidade Universitaria, 05508-900 Sao Paulo (Brazil) and Brazilian Center for Research in Physics, Rua Xavier Sigaud, 150, 22290-180 Rio de Janeiro (Brazil)

2006-05-15T23:59:59.000Z

437

Radiative corrections in 5D and 6D expanding in winding modes  

Science Journals Connector (OSTI)

We compute radiative corrections in five- and six-dimensional field theories, using winding modes in mixed momentum-coordinate space. This method provides a simple way of finding UV divergencies, finite corrections and localized terms when the space is compactified on orbifolds. As an application we compute the finite piece of scalar masses, the logarithmic contributions to the couplings and the effect of localized parallel and perpendicular kinetic terms. We apply it to get a two loop effective potential that can stabilize large extra dimensions.

Leandro Da Rold

2004-05-20T23:59:59.000Z

438

The VLF fingerprint of elves: Step-like and long-recovery early VLF perturbations caused by powerful CG lightning EM pulses  

E-Print Network (OSTI)

of a causative cloud-to-ground (CG) lightning flash, thus the term "early" signifies a direct lightning effect the initial causative CG flash [Haldoupis et al., 2006]. Early events are distinct from "lightning by powerful ±CG lightning EM pulses Christos Haldoupis,1 Morris Cohen,2 Enrico Arnone,3 Benjamin Cotts,4

439

Dielectric tensor and plasmon-phonon modes in semiconductors with anisotropic conduction valleys  

Science Journals Connector (OSTI)

The wavevector- and frequency-dependent self-consistent field approximation dielectric tensor of an n-type semiconductor with anisotropic, multi-valley and parabolic conduction band is derived taking into account the optical phonon contribution. The high-frequency and long-wavelength form of this tensor, calculated in the degenerate plasma limit, is used for the normal mode analysis. The dispersion equation for the plasmon-phonon modes with long wavelength is found to have an isotropic-like form, epsilon 1(q, omega )=0, except for the case of the lower-frequency mode in the strongly anisotropic, very dense conduction band plasma; epsilon 1(q, omega ) is the appropriate wave-vector-direction-dependent longitudinal dielectric function. The plasmon-phonon modes dispersion relation is established up to terms quadratic in the wavevector and the dependence of the frequencies on the propagation direction is discussed. The dispersibility of the lower-frequency mode has a maximum close to the point where the phonon frequency omega LO is equal to the plasma frequency omega p. Special attention is paid to lead salts and numerical estimates are made for PbTe.

S Goettig

1981-01-01T23:59:59.000Z

440

Viscosity of neutron star matter and $r$-modes in rotating pulsars  

E-Print Network (OSTI)

We study viscosity of the neutron star matter and $r$-mode instability in rotating neutron stars. Contributions to the shear and bulk viscosities from various processes are calculated with account of in-medium modifications of the nucleon-nucleon interaction. A softening of the pion mode and a possibility of the pion condensation are included. The nucleon pairing is incorporated. In the shear viscosity we include the lepton contribution calculated with account of the Landau damping in the photon exchange, the nucleon contribution described by the medium-modified one pion exchange, and other terms, such as the novel phonon contribution in the 1S$_0$ superfluid neutron phase, and the neutrino term in the neutrino opacity region. The nucleon shear viscosity depends on the density rather moderately and proves to be much less than the lepton term. Among the terms contributing to the bulk viscosity, the term from the medium modified Urca reactions possesses strongest density dependence because of the pion softening...

Kolomeitsev, E E

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Surface instability on a metal target from multi-pulse KrF laser ablation  

SciTech Connect

Aluminum targets were ablated by focusing a KrF excimer laser down to a spot size of 0.05 cm{sup 2} with a fluence of approximately 4.9 J/cm{sup 2}. After a few tens of pulses, surface irregularities (corrugations and pits) progressively emerge, with size 1--100 {micro}m which is much larger than the laser wavelength. After hundreds of laser pulses, large scale wavelike patterns, on the order of 20 {micro}m, are observed on the aluminum surface. The authors propose that these wave patterns are caused by the Kelvin-Helmholtz instability at the interface of the molten aluminum and the plasma plume. A parametric study is given in terms of the molten layer`s thickness and of the spatial extent and kinetic energy density in the laser-produced plasma plume. Also included is an estimate of the cumulative growth in a multi-pulse laser ablation experiment. These estimates indicate that the Kelvin-Helmholtz instability is a viable mechanism for the formation of the large scale structures. Once formed, these large scale surface roughness causes multiple reflections of the laser light, and may increase the absorption coefficient over a pristine, flat surface by an order of magnitude.

Ang, L.K.; Lau, Y.Y.; Gilgenbach, R.M.; Kovaleski, S.D. [Univ. of Michigan, Ann Arbor, MI (United States); Spindler, H.L. [Boeing Corp., Seattle, WA (United States); Lash, J.S. [Sandia National Lab., Albuquerque, NM (United States)

1998-12-31T23:59:59.000Z

442

Precision lifetime measurements of a single trapped ion with ultrafast laser pulses  

E-Print Network (OSTI)

We report precision measurements of the excited state lifetime of the $5p$ $^2P_{1/2}$ and $5p$ $^2P_{3/2}$ levels of a single trapped Cd$^+$ ion. The ion is excited with picosecond laser pulses from a mode-locked laser and the distribution of arrival times of spontaneously emitted photons is recorded. The resulting lifetimes are 3.148 $\\pm$ 0.011 ns and 2.647 $\\pm$ 0.010 ns for $^2P_{1/2}$ and $^2P_{3/2}$ respectively. With a total uncertainty of under 0.4%, these are among the most precise measurements of any atomic state lifetimes to date.

D. L. Moehring; B. B. Blinov; D. W. Gidley; R. N. Kohn Jr.; M. J. Madsen; T. D. Sanderson; R. S. Vallery; C. Monroe

2005-05-15T23:59:59.000Z

443

Precision lifetime measurements of a single trapped ion with ultrafast laser pulses  

SciTech Connect

We report precision measurements of the excited state lifetime of the 5p {sup 2}P{sub 1/2} and 5p {sup 2}P{sub 3/2} levels of a single trapped Cd{sup +} ion. Combining ion trap and ultrafast laser technologies, the ion is excited with picosecond laser pulses from a mode-locked laser and the distribution of arrival times of spontaneously emitted photons is recorded. The resulting lifetimes are 3.148{+-}0.011 ns and 2.647{+-}0.010 ns for {sup 2}P{sub 1/2} and {sup 2}P{sub 3/2} respectively. With a total uncertainty of under 0.4%, these are among the most precise measurements of any atomic state lifetimes to date.

Moehring, D. L.; Blinov, B. B.; Gidley, D. W.; Kohn, R. N. Jr.; Madsen, M. J.; Sanderson, T. D.; Vallery, R. S.; Monroe, C. [FOCUS Center and Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)

2006-02-15T23:59:59.000Z

444

A Gyrokinetic 1D Scrape-Off Layer Model of an ELM Heat Pulse  

E-Print Network (OSTI)

We have applied an electrostatic gyrokinetic-based model to simulate parallel plasma transport in the scrape-off layer to a divertor plate. We focus on a test problem that has been studied previously, using parameters chosen to model a heat pulse driven by an edge localized mode (ELM) in JET. Previous work has used direct particle-in-cell equations with full dynamics, or Vlasov or fluid equations with only parallel dynamics. With the use of the gyrokinetic quasineutrality equation and logical sheath boundary conditions, spatial and temporal resolution requirements are no longer set by the electron Debye length and plasma frequency, respectively. This test problem also helps illustrate some of the physics contained in the Hamiltonian form of the gyrokinetic equations and some of the numerical challenges in developing an edge gyrokinetic code.

Shi, E L; Hammett, G W

2014-01-01T23:59:59.000Z

445

Effect of Nuclear Motion on Molecular High-Order Harmonics and on Generation of Attosecond Pulses in Intense Laser Pulses  

SciTech Connect

We calculate harmonic spectra and shapes of attosecond-pulse trains using numerical solutions of Non-Born-Oppenheimer time-dependent Shroedinger equation for 1D H{sub 2} molecules in an intense laser pulse. A very strong signature of nuclear motion is seen in the time profiles of high-order harmonics. In general the nuclear motion shortens the part of the attosecond-pulse train originating from the first electron contribution, but it may enhance the second electron contribution for longer pulses. The shape of time profiles of harmonics can thus be used for monitoring the nuclear motion.

Bandrauk, Andre D.; Chelkowski, Szczepan; Kawai, Shinnosuke; Lu, Huizhong [Departement de Chimie, Universite de Sherbrooke, Sherbrooke, Qc, J1K 2R1 (Canada)

2008-10-10T23:59:59.000Z

446

Ultra-wideband short-pulse radar with range accuracy for short range detection  

DOE Patents (OSTI)

An ultra-wideband (UWB) radar transmitter apparatus comprises a pulse generator configured to produce from a sinusoidal input signal a pulsed output signal having a series of baseband pulses with a first pulse repetition frequency (PRF). The pulse generator includes a plurality of components that each have a nonlinear electrical reactance. A signal converter is coupled to the pulse generator and configured to convert the pulsed output signal into a pulsed radar transmit signal having a series of radar transmit pulses with a second PRF that is less than the first PRF.

Rodenbeck, Christopher T; Pankonin, Jeffrey; Heintzleman, Richard E; Kinzie, Nicola Jean; Popovic, Zorana P

2014-10-07T23:59:59.000Z

447

EPAct Transportation Regulatory Activities: Key Terms  

NLE Websites -- All DOE Office Websites (Extended Search)

Key Terms Key Terms to someone by E-mail Share EPAct Transportation Regulatory Activities: Key Terms on Facebook Tweet about EPAct Transportation Regulatory Activities: Key Terms on Twitter Bookmark EPAct Transportation Regulatory Activities: Key Terms on Google Bookmark EPAct Transportation Regulatory Activities: Key Terms on Delicious Rank EPAct Transportation Regulatory Activities: Key Terms on Digg Find More places to share EPAct Transportation Regulatory Activities: Key Terms on AddThis.com... Home About Covered Fleets Compliance Methods Alternative Fuel Petitions Resources Guidance Documents Statutes & Regulations Program Annual Reports Fact Sheets Newsletter Case Studies Workshops Tools Key Terms FAQs Key Terms The Energy Policy Act (EPAct) includes specific terminology related to

448

Long Term World Oil Supply  

Gasoline and Diesel Fuel Update (EIA)

0 0 Notes: The following pages summarize a recent EIA presentation on estimates of the world conventional oil resource base and the year when production from it will peak and then begin to decline. A version of this presentation was given by former EIA Administrator Jay Hakes to the April 18, 2000 meeting of the American Association of Petroleum Geologists in New Orleans, Louisiana. Specific information about this presentation may be obtained from John Wood (john.wood@eia.doe.gov), Gary Long (gary.long@eia.doe.gov) or David Morehouse (david.morehouse@eia.doe.gov). Long Term World Oil Supply http://www.eia.doe.gov/pub/oil_gas/petroleum/presentations/2000/long_term_supply/sld001.htm [8/10/2000 4:56:23 PM] Slide 2 of 20 http://www.eia.doe.gov/pub/oil_gas/petroleum/presentations/2000/long_term_supply/sld002.htm [8/10/2000 4:56:24 PM]

449

Experimental investigation of dielectric barrier discharge plasma actuators driven by repetitive high-voltage nanosecond pulses with dc or low frequency sinusoidal bias  

SciTech Connect

Experimental studies were conducted of a flow induced in an initially quiescent room air by a single asymmetric dielectric barrier discharge driven by voltage waveforms consisting of repetitive nanosecond high-voltage pulses superimposed on dc or alternating sinusoidal or square-wave bias voltage. To characterize the pulses and to optimize their matching to the plasma, a numerical code for short pulse calculations with an arbitrary impedance load was developed. A new approach for nonintrusive diagnostics of plasma actuator induced flows in quiescent gas was proposed, consisting of three elements coupled together: the schlieren technique, burst mode of plasma actuator operation, and two-dimensional numerical fluid modeling. The force and heating rate calculated by a plasma model was used as an input to two-dimensional viscous flow solver to predict the time-dependent dielectric barrier discharge induced flow field. This approach allowed us to restore the entire two-dimensional unsteady plasma induced flow pattern as well as characteristics of the plasma induced force. Both the experiments and computations showed the same vortex flow structures induced by the actuator. Parametric studies of the vortices at different bias voltages, pulse polarities, peak pulse voltages, and pulse repetition rates were conducted experimentally. The significance of charge buildup on the dielectric surface was demonstrated. The charge buildup decreases the effective electric field in the plasma and reduces the plasma actuator performance. The accumulated surface charge can be removed by switching the bias polarity, which leads to a newly proposed voltage waveform consisting of high-voltage nanosecond repetitive pulses superimposed on a high-voltage low frequency sinusoidal voltage. Advantages of the new voltage waveform were demonstrated experimentally.

Opaits, Dmitry F.; Likhanskii, Alexandre V.; Neretti, Gabriele; Zaidi, Sohail; Shneider, Mikhail N.; Miles, Richard B. [Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Macheret, Sergey O. [Lockheed Martin Aeronautics Company, Palmdale, California 93599 (United States)

2008-08-15T23:59:59.000Z

450

Bipolar pulse field for magnetic refrigeration  

DOE Patents (OSTI)

A magnetic refrigeration apparatus includes first and second steady state magnets, each having a field of substantially equal strength and opposite polarity, first and second bodies made of magnetocaloric material disposed respectively in the influence of the fields of the first and second steady state magnets, and a pulsed magnet, concentric with the first and second steady state magnets, and having a field which cycles between the fields of the first and second steady state magnets, thereby cyclically magnetizing and demagnetizing and thus heating and cooling the first and second bodies. Heat exchange apparatus of suitable design can be used to expose a working fluid to the first and second bodies of magnetocaloric material. A controller is provided to synchronize the flow of working fluid with the changing states of magnetization of the first and second bodies. 2 figs.

Lubell, M.S.

1994-10-25T23:59:59.000Z

451

Supergiant Pulses from Extragalactic Neutron Stars  

E-Print Network (OSTI)

We evaluate the hypothesis that extragalactic radio bursts originate from neutron stars. These could be active pulsars or dormant, slowly spinning objects, but the different population distances for these two classes require correspondingly different contributions to burst dispersion measures from any host or intervening galaxies combined with the intergalactic medium. The large, apparent burst rate $\\sim 10^4~$ sky$^{-1}~$ day$^{-1}$ is comparable to the core-collapse supernova rate in a Hubble volume and can be accommodated by a single burst per object in the resulting large reservoir of $\\sim 10^{17}~$ neutron stars. A smaller population distance requires more bursts per object but the likelihood of seeing repeated bursts from any single object is extremely low on human timescales. Gravitational microlensing could play a role for high redshift sources. Extrapolation of the Crab pulsar's giant pulses --- exemplars of coherent, high brightness temperature radiation --- to a rate of one per $10^3~$yr yields a...

Cordes, J M

2015-01-01T23:59:59.000Z

452

Pulse combusted acoustic agglomeration apparatus and process  

DOE Patents (OSTI)

An improved apparatus and process for removal of particulates entrained in a gas stream are provided. The removal process employs a pulse combustor to provide an acoustic pressure wave to acoustically enhance agglomeration of particulates which may be collected and removed using a conventional separation apparatus. The apparatus may be employed as a direct fired system for improved operation of gas-operated equipment such as a gas turbine, or may, alternatively, be employed as an add-on subsystem for combustion exhaust clean-up. Additionally, added particulates may include a sorbent for effecting sorption of other contaminants such as sulfur. Various other particulates for contaminant removal may also be introduced into the system as exemplified by alkali-gettering agents.

Mansour, Momtaz N. (Columbia, MD); Chandran, Ravi (Ellicott City, MD)

1994-01-01T23:59:59.000Z

453

Pulse combusted acoustic agglomeration apparatus and process  

DOE Patents (OSTI)

An improved apparatus and process for removal of particulates entrained in a gas stream are provided. The removal process employs a pulse combustor to provide an acoustic pressure wave to acoustically enhance bimodal agglomeration of particulates which may be collected and removed using a conventional separation apparatus. A particulate having a size different from the size of the particulate in the gas stream to be cleaned is introduced into the system to effectuate the bimodal process. The apparatus may be employed as a direct fired system for improved operation of gas-operated equipment such as a gas turbine, or may, alternatively, be employed as an add-on subsystem for combustion exhaust clean-up. Additionally, the added particulate may be a sorbent for effecting sorption of other contaminants such as sulfur. Various other particulates for contaminant removal may also be introduced into the system as exemplified by alkali-gettering agents.

Mansour, Momtaz N. (Columbia, MD)

1993-01-01T23:59:59.000Z

454

Mode-synthesizing atomic force microscopy and mode-synthesizing sensing  

DOE Patents (OSTI)

A method of analyzing a sample that includes applying a first set of energies at a first set of frequencies to a sample and applying, simultaneously with the applying the first set of energies, a second set of energies at a second set of frequencies, wherein the first set of energies and the second set of energies form a multi-mode coupling. The method further includes detecting an effect of the multi-mode coupling.

Passain, Ali; Thundat, Thomas George; Tetard, Laurene

2014-07-22T23:59:59.000Z

455

Ultrashort-pulse laser generated nanoparticles of energetic materials  

DOE Patents (OSTI)

A process for generating nanoscale particles of energetic materials, such as explosive materials, using ultrashort-pulse laser irradiation. The use of ultrashort laser pulses in embodiments of this invention enables one to generate particles by laser ablation that retain the chemical identity of the starting material while avoiding ignition, deflagration, and detonation of the explosive material.

Welle, Eric J. (Niceville, NM); Tappan, Alexander S. (Albuquerque, NM); Palmer, Jeremy A. (Albuquerque, NM)

2010-08-03T23:59:59.000Z

456

Experimental study of a pulse detonation rocket with Shchelkin spiral  

E-Print Network (OSTI)

Experimental study of a pulse detonation rocket with Shchelkin spiral F.K. Lu, J.M. Meyers, and D There is much recent interest in the development of propulsion systems using high- frequency pulsed detonations detonations in a short distance. The direct initiation of detonation requires an inordinate amount of energy

Texas at Arlington, University of

457

Development of a Large Pulse Detonation Engine Demonstrator  

E-Print Network (OSTI)

Development of a Large Pulse Detonation Engine Demonstrator Frank K. Lu, J. David Carter and constructed to study pulse detonation engine (PDE) operations under a broad range of test parameters to facilitate deflagration-to-detonation transition. The main sections of the combustor were fitted with fully

Texas at Arlington, University of

458

Perfect image segmentation using pulse coupled neural networks  

Science Journals Connector (OSTI)

This paper describes a method for segmenting digital images using pulse coupled neural networks (PCNN). The pulse coupled neuron (PCN) model used in PCNN is a modification of the cortical neuron model of Eckhorn et al. (1990). A single layered laterally ...

G. Kuntimad; H. S. Ranganath

1999-05-01T23:59:59.000Z

459

Optical fiber based ultrashort pulse multispectral nonlinear optical microscopy  

E-Print Network (OSTI)

broadband sub-10-fs pulses. An all-mirror dispersion-compensation setup is used to correct for quadratic and cubic phase distortions induced within the NLOM. Mouse tail tendon was used to characterize sub-10-fs pulses by interferometric autocorrelation...

Larson, Adam Michael

2009-05-15T23:59:59.000Z

460

RICE UNIVERSITY Pulsed Dye Laser For Excitation Of Strontium  

E-Print Network (OSTI)

RICE UNIVERSITY Pulsed Dye Laser For Excitation Of Strontium by Priya Gupta A Thesis Submitted April, 2004 #12;2 #12;#12;iii ABSTRACT Pulsed Dye Laser For Excitation Of Strontium by Priya Gupta that is used to make ultracold strontium plasma. In order to make ultracold plasma, we cool and trap strontium

Killian, Thomas C.

Note: This page contains sample records for the topic "term pulse mode" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Beams 92: Proceedings. Volume 1: Invited papers, pulsed power  

SciTech Connect

This report contains papers on the following topics: Ion beam papers; electron beam, bremsstrahlung, and diagnostics papers; radiating Z- pinch papers; microwave papers; electron laser papers; advanced accelerator papers; beam and pulsed power applications papers; pulsed power papers; and these papers have been indexed separately elsewhere.

Mosher, D.; Cooperstein, G. [eds.] [Naval Research Lab., Washington, DC (United States)

1993-12-31T23:59:59.000Z

462

Raman Amplification of Laser Pulses in Microcapillary Plasmas  

E-Print Network (OSTI)

of overcoming the power limit of current chirped-pulse-amplification (CPA) CP641, X-Ray Lasers 2002: 8th International Conference on X-Ray Lasers, edited by J. J. Rocca et al. > 2002American Institute of Physics 0 of the optics. Such Raman amplifiers can be useful to produce ultra-intense laser pulses for pumping soft x-ray

463

Short pulse evolution in the Boeing APLE oscillator  

Science Journals Connector (OSTI)

The Boeing average power laser experiment (APLE) oscillator is investigated using two- and three-dimensional simulations. The evolution of optical pulses in the presence of an electron pulse energy slew is examined. The most stable operation of the oscillator is found for larger values of desynchronism where the electron energy spread is minimized in preparation for input into the high power amplifier.

K.A. Sturgess; D.J. Frost; W.B. Colson

1993-01-01T23:59:59.000Z

464

CenterPulse Wisconsin National Primate Research Center  

E-Print Network (OSTI)

CenterPulse Wisconsin National Primate Research Center University of Wisconsin-Madison Contents Welcome to our year in review, CenterPulse. We hope you enjoy the new format. In making our news more Affiliates 3 Just Published 7 In the news 7 WIMR Opening and Board Tour 8 Reduced Diet Thwarts Aging 10 Kate

Wisconsin at Madison, University of

465

Electron acceleration by Z-mode and whistler-mode waves  

SciTech Connect

We carried out a series of particle simulations to study electron acceleration by Z-mode and whistler-mode waves generated by an electron ring distribution. The electron ring distribution leads to excitations of X-mode waves mainly in the perpendicular direction, Z-mode waves in the perpendicular and parallel directions, and whistler-mode waves mainly in the parallel direction. The parallel Z- and whistler-mode waves can lead to an effective acceleration of ring electrons. The electron acceleration is mainly determined by the wave amplitude and phase velocity, which in turn is affected by the ratio of electron plasma to cyclotron frequencies. For the initial kinetic energy ranging from 100 to 500 keV, the peak energy of the accelerated electrons is found to reach 28 times the initial kinetic energy. We further study the acceleration process by test-particle calculations in which electrons interact with one, two, or four waves. The electron trajectories in the one-wave case are simple diffusion curves. In the multi-wave cases, electrons are accelerated simultaneously by counter-propagating waves and can have a higher final energy.

Lee, K. H. [Institute of Space Science, National Central University, Zhongli, Taiwan (China)] [Institute of Space Science, National Central University, Zhongli, Taiwan (China); Omura, Y. [Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto (Japan)] [Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto (Japan); Lee, L. C. [Institute of Space Science, National Central University, Zhongli, Taiwan (China) [Institute of Space Science, National Central University, Zhongli, Taiwan (China); Institute of Earth Science, Academia Sinica, Nankang, Taiwan (China)

2013-11-15T23:59:59.000Z

466

MHK Technologies/Pulse-Stream 120 | Open Energy Information  

Open Energy Info (EERE)

Pulse-Stream 120 Pulse-Stream 120 < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Technology Profile Primary Organization Pulse Tidal Ltd Technology Resource Click here Wave Technology Type Click here Oscillating Wave Surge Converter Technology Description Building on the success of the Pulse-Stream 100 which was installed in 2009, Pulse Tidal has formed a large technical team and secured a European Union grant for development of a commercial scale product. This device will be installed in Scotland in 2012. Mooring Configuration Secured to the seabed with drilled and grouted pin-piles Optimum Marine/Riverline Conditions 2.5m/s flow-rate. Depth average 60ft. Technology Dimensions Length (m) 10 Width (m) 45 Height (m) 13

467

Attenuation structure of Coso geothermal area, California, from wave pulse  

Open Energy Info (EERE)

structure of Coso geothermal area, California, from wave pulse structure of Coso geothermal area, California, from wave pulse widths Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Attenuation structure of Coso geothermal area, California, from wave pulse widths Details Activities (1) Areas (1) Regions (0) Abstract: Pulse width data are used to invert for attenuation structure in the Coso geothermal area, California. The dataset consists of pulse width measurements of 838 microseismic events recorded on a seismic array of 16 downhole stations between August 1993 and March 1994. The quality factor Q correlates well with surface geology and surface heat flow observations. A broad region of low Q (≈ 30 to 37) is located at 0.5 to 1.2 km in depth below Devil's Kitchen, Nicol Prospects, and Coso Hot Springs. A vertical,

468

High-voltage air-core pulse transformers  

SciTech Connect

General types of air core pulse transformers designed for high voltage pulse generation and energy transfer applications are discussed with special emphasis on pulse charging systems which operate up to the multi-megavolt range. The design, operation, dielectric materials, and performance are described. It is concluded that high voltage air core pulse transformers are best suited to applications outside the normal ranges of conventional magnetic core transformers. In general these include charge transfer at high power levels and fast pulse generation with comparatively low energy. When properly designed and constructed, they are capable of delivering high energy transfer efficiency and have demonstrated superior high voltage endurance. The principal disadvantage of high voltage air core transformers is that they are not generally available from commercial sources. Consequently, the potential user must become thoroughly familiar with all aspects of design, fabrication and system application before he can produce a high performance transformer system. (LCL)

Rohwein, G. J.

1981-01-01T23:59:59.000Z

469

Molecular spinning by a chiral train of short laser pulses  

E-Print Network (OSTI)

We provide a detailed theoretical analysis of molecular rotational excitation by a chiral pulse train -- a sequence of linearly polarised pulses with the polarisation direction rotating from pulse to pulse by a controllable angle. Molecular rotation with a preferential rotational sense (clockwise or counter-clockwise) can be excited by this scheme. We show that the directionality of the rotation is caused by quantum interference of different excitation pathways. The chiral pulse train is capable of selective excitation of molecular isotopologues and nuclear spin isomers in a mixture. We demonstrate this using 14N2 and 15N2 as examples for isotopologues, and para- and ortho-nitrogen as examples for nuclear spin isomers.

Johannes Flo; Ilya Sh. Averbukh

2012-10-31T23:59:59.000Z

470

Plasma Switch for High-Power Active Pulse Compressor  

SciTech Connect

Results are presented from experiments carried out at the Naval Research Laboratory X-band magnicon facility on a two-channel X-band active RF pulse compressor that employed plasma switches. Experimental evidence is shown to validate the basic goals of the project, which include: simultaneous firing of plasma switches in both channels of the RF circuit, operation of quasi-optical 3-dB hybrid directional coupler coherent superposition of RF compressed pulses from both channels, and operation of the X-band magnicon directly in the RF pulse compressor. For incident 1.2 ?s pulses in the range 0.63 ? 1.35 MW, compressed pulses of peak powers 5.7 ? 11.3 MW were obtained, corresponding to peak power gain ratios of 8.3 ? 9.3. Insufficient bakeout and conditioning of the high-power RF circuit prevented experiments from being conducted at higher RF input power levels.

Hirshfield, Jay L. [Omega-P, Inc.] [Omega-P, Inc.

2013-11-04T23:59:59.000Z

471

Modifying molecule-surface scattering by ultrashort laser pulses  

SciTech Connect

In recent years it has become possible to align molecules in free space using ultrashort laser pulses. Here we explore two schemes for controlling molecule-surface scattering processes and which are based on laser-induced molecular alignment. In the first scheme, a single ultrashort nonresonant laser pulse is applied to a molecular beam hitting the surface. This pulse modifies the angular distribution of the incident molecules and causes the scattered molecules to rotate with a preferred sense of rotation (clockwise or counterclockwise). In the second scheme, two properly delayed laser pulses are applied to a molecular beam composed of two chemically close molecular species (isotopes, or nuclear-spin isomers). As the result of the double-pulse excitation, these species are selectively scattered to different angles after the collision with the surface. These effects may provide new means for the analysis and separation of molecular mixtures.

Khodorkovsky, Yuri; Averbukh, Ilya Sh. [Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100 (Israel); Manson, J. R. [Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634 (United States)

2011-11-15T23:59:59.000Z

472

OBSERVED DAMPING OF THE SLOW MAGNETOACOUSTIC MODE  

SciTech Connect

Spectroscopic and stereoscopic imaging observations of slow magnetoacoustic wave propagation within a coronal loop are investigated to determine the decay length scale of the slow magnetoacoustic mode in three dimensions and the density profile within the loop system. The slow wave is found to have an e-folding decay length scale of 20,000{sup +4000}{sub -3000} km with a uniform density profile along the loop base. These observations place quantitative constraints on the modeling of wave propagation within coronal loops. Theoretical forward modeling suggests that magnetic field line divergence is the dominant damping factor and thermal conduction is insufficient, given the observed parameters of the coronal loop temperature, density, and wave mode period.

Marsh, M. S.; Walsh, R. W. [Jeremiah Horrocks Institute for Astrophysics and Supercomputing, University of Central Lancashire, Preston PR1 2HE (United Kingdom); De Moortel, I., E-mail: mike.s.marsh@gmail.com, E-mail: mmarsh@uclan.ac.uk [School of Mathematics and Statistics, University of St Andrews, St Andrews KY16 9SS (United Kingdom)

2011-06-20T23:59:59.000Z

473

Geodesic stability, Lyapunov exponents and quasinormal modes  

E-Print Network (OSTI)

Geodesic motion determines important features of spacetimes. Null unstable geodesics are closely related to the appearance of compact objects to external observers and have been associated with the characteristic modes of black holes. By computing the Lyapunov exponent, which is the inverse of the instability timescale associated with this geodesic motion, we show that, in the eikonal limit, quasinormal modes of black holes in any dimensions are determined by the parameters of the circular null geodesics. This result is independent of the field equations and only assumes a stationary, spherically symmetric and asymptotically flat line element, but it does not seem to be easily extendable to anti-de Sitter spacetimes. We further show that (i) in spacetime dimensions greater than four, equatorial circular timelike geodesics in a Myers-Perry black hole background are unstable, and (ii) the instability timescale of equatorial null geodesics in Myers-Perry spacetimes has a local minimum for spacetimes of dimension d > 5.

Vitor Cardoso; Alex S. Miranda; Emanuele Berti; Helvi Witek; Vilson T. Zanchin

2009-03-12T23:59:59.000Z

474

Tensor modes on the string theory landscape  

E-Print Network (OSTI)

We attempt an estimate for the distribution of the tensor mode fraction $r$ over the landscape of vacua in string theory. The dynamics of eternal inflation and quantum tunneling lead to a kind of democracy on the landscape, providing no bias towards large-field or small-field inflation regardless of the class of measure. The tensor mode fraction then follows the number frequency distributions of inflationary mechanisms of string theory over the landscape. We show that an estimate of the relative number frequencies for small-field vs large-field inflation, while unattainable on the whole landscape, may be within reach as a regional answer for warped Calabi-Yau flux compactifications of type IIB string theory.

Alexander Westphal

2012-12-22T23:59:59.000Z

475

??? Decay Mode of Neutral K Mesons  

Science Journals Connector (OSTI)

The decay K??++?-+?, ??e++e- has been observed in the film of the UCRL 72-in. hydrogen bubble chamber exposed to a beam of 1325-MeV/c momentum negative pions. This event unambiguously fits only the decay mode K??+?+?, but because the K's life span is almost exactly one K10 lifetime it is impossible to say whether it is a direct ??? or inner bremsstrahlung accompanying normal K10?2? decay.

D. Stern

1962-10-01T23:59:59.000Z

476

Stabilizing windings for tilting and shifting modes  

DOE Patents (OSTI)

This invention relates to passive conducting loops for stabilizing a plasma ring against unstable tilting and/or shifting modes. To this end, for example, plasma ring in a spheromak is stabilized by a set of four figure-8 shaped loops having one pair on one side of the plasma and one pair on the other side with each pair comprising two loops whose axes are transverse to each other.

Jardin, Stephen C. (Princeton, NJ); Christensen, Uffe R. (Princeton, NJ)

1984-01-01T23:59:59.000Z

477

Long-term earthquake clustering  

Science Journals Connector (OSTI)

......81, 1280-1283. Smalley R. F. Jr , Chatelain J. L., Turcotte...77, 868-876. Wallace R. E. , Davis J. F., Mcnally K. C., 1984. Terms for expressing...Acad. Sci. USA, Smalley, R. F., Jr, Chatelain, J.-L., Turcotte......

Yan Y. Kagan; David D. Jackson

478

Calendar Year study term 1  

E-Print Network (OSTI)

planet is in need of clean and renewable sources of energy such as wind, solar, geothermal, tidal and Renewable Energy Sources Electrical Power Engineering Study Term 6 Probability and Statistics Systems and biomass. Carleton University's program in Sustainable and Renewable Energy Engineering provides you

Dawson, Jeff W.

479

Dynamics of local micro-breakdown in the Geiger mode of avalanche photodiodes  

SciTech Connect

Mathematical modeling methods were used to study the dynamics of micro-breakdown development in structures of silicon avalanche photodiodes. The constructed model considers the locality of the avalanchexs multiplication region appearing during single photon absorption and the delay of the avalanchexs current spreading over the rear electrode of the diode. The calculations showed two different phases of transient process of the formation of the electrical signal, i.e., the rapid and slow ones due to current spreading and ordinary RC recharge, respectively. The load resistances required to implement the pulsed mode of operation of the structures of the avalanche photodiode were calculated for a series of actual diode capacitances and spreading resistances of the rear electrode.

Verhovtseva, A. V., E-mail: alevteena@gmail.com; Gergel, V. A. [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Russian Federation)], E-mail: gergel@mail.cplire.ru

2009-07-15T23:59:59.000Z

480

Comparison of H-Mode Plasmas Diverted to Solid and Liquid Lithium Surfaces  

SciTech Connect

Experiments were conducted with a Liquid Lithium Divertor (LLD) in NSTX. Among the goals was to use lithium recoating to sustain deuterium (D) retention by a static liquid lithium surface, approximating the ability of flowing liquid lithium to maintain chemical reactivity. Lithium evaporators were used to deposit lithium on the LLD surface. Improvements in plasma edge conditions were similar to those with lithiated graphite plasma-facing components (PFCs), including an increase in confinement over discharges without lithiumcoated PFCs and ELM reduction during H-modes. With the outer strike point on the LLD, the D retention in the LLD was about the same as that for solid lithium coatings on graphite, or about two times that achieved without lithium PFC coatings. There were also indications of contamination of the LLD surface, possibly due erosion and redeposition of carbon from PFCs. Flowing lithium may thus be needed for chemically active PFCs during long-pulse operation.

R. Kaita, et. al.

2012-07-20T23:59:59.000Z

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481

Long?term variations of ice breaking noise in Antarctica  

Science Journals Connector (OSTI)

Numerous low frequency transient signals arriving from Antarctica have been detected in five?year sea noise recordings in 2002?2006 at the hydroacoustic listening station deployed off Cape Leeuwin in Western Australia as part of the International Monitoring System of the Comprehensive Nuclear?Test?Ban Treaty. The majority of these signals consist of a single arrival of mode 1 which dominates the higher modes and undergoes strong frequency dispersion due to long?range propagation in the polar ocean environment. These signals are believed to be emitted primarily by ice rifting and breaking events on the Antarctic shelf. Several regions along the Antarctic coast associated with certain glaciers and ice tongues were found to persistently be much more active in generatingicenoise than other parts of the Antarctic shelf. An analysis of long?term changes in the frequency of occurrence of ice events showed noticeable seasonal cycles but did not reveal any significant interannual variations against the background of short?term fluctuations. Some of the ice events detected at the Cape Leeuwin station were also identified in sea noise recordings made on autonomous acoustic loggers deployed on the Antarctic shelf which allowed us to investigate characteristics of the acoustic signals from ice events near their origins.

Alexander Gavrilov; Binghui Li

2008-01-01T23:59:59.000Z

482

Pulse radiolysis of liquid water using picosecond electron pulses produced by a table-top terawatt laser system  

E-Print Network (OSTI)

Pulse radiolysis of liquid water using picosecond electron pulses produced by a table-top terawatt into a supersonic helium gas jet are used to ionize liquid water. The decay of the hydrated electrons produced electron generator is shown, for the first time, to produce sufficient charge to conduct time resolved

Umstadter, Donald

483

Spectral Broadening of Femtosecond Mid-IR Pulses Coupled Into Quantum Cascade Lasers  

Science Journals Connector (OSTI)

Femtosecond 4.72 ?m Mid-IR pulses are coupled into a pulsed biased, room temperature 4.72 ?m QCL, resulting in 2X spectra broadening of the input pulses.

Liu, Sheng; Cai, Hong; Lalanne, Elaine; Liu, Peter Q; Cheng, Xiaojun; Gmachl, Claire; Johnson, Anthony M

484

Increasing the CO tolerance of PEM fuel cells via current pulsing and self-oxidation  

E-Print Network (OSTI)

An investigation was conducted to determine and compare the effect of cell current pulsing and "self-oxidation" in increasing the CO tolerance of a PEM fuel cell. The most effective pulsing parameter values were also determined. Current pulsing...

Thomason, Arthur Hugh

2004-09-30T23:59:59.000Z

485

Scaling up the energy of THz pulses created by optical rectification  

Science Journals Connector (OSTI)

The possibility for up-scaling the energy of sub-ps THz pulses generated by tilted pulse front excitation is demonstrated. Using 150-fs-long 500 ?J optical pump pulses at 800 nm up...

Stepanov, A; Kuhl, J; Kozma, I; Riedle, E; Almsi, G; Hebling, J

2005-01-01T23:59:59.000Z

486

The impact of pulsed irradiation upon neutron activation calculations for inertial and magnetic fusion energy power plants  

SciTech Connect

Inertial fusion energy (IFE) and magnetic fusion energy (MFE) power plants will probably operate in a pulsed mode. The two different schemes, however, will have quite different time periods. Typical repetition rates for IFE power plants will be 1-5 Hz. MFE power plants will ramp up in current for about 1 hour, shut down for several minutes, and repeat the process. Traditionally, activation calculations for IFE and MFE power plants have assumed continuous operation and used either the ``steady state`` (SS) or ``equivalent steady state`` (ESS) approximations. It has been suggested recently that the SS and ESS methods may not yield accurate results for all radionuclides of interest. The present work expands that of Sisolak, et al. by applying their formulae to conditions which might be experienced in typical IFE and MFE power plants. In addition, complicated, multi-step reaction/decay chains are analyzed using an upgraded version of the ACAB radionuclide generation/depletion code. Our results indicate that the SS method is suitable for application to MFE power plant conditions. We also find that the ESS method generates acceptable results for radionuclides with half-lives more than a factor of three greater than the time between pulses. For components that are subject to 0.05 Hz (or more frequent) irradiation (such as coolant), use of the ESS method is recommended. For components or materials that are subject to less frequent irradiation (such as high-Z target materials), pulsed irradiation calculations should be used.

Latkowski, J.F. [Lawrence Livermore National Lab., CA (United States); Sanz, J. [Universidad Politecnica de Madrid (Spain); Vujic, J.L. [California Univ., Berkeley, CA (United States)

1996-06-26T23:59:59.000Z

487

A battery-operated, stabilized, high-energy pulsed electron gun for the production of rare gas excimers  

SciTech Connect

We report on the design of a new type of hot-filament electron gun delivering fairly high current (a few hundreds of {mu} A) at high voltage (up to 100 kV) in continuous or pulsed mode. Its novel features are that the filament is heated by means of a pack of rechargeable batteries floated atop the high-voltage power supply in order to get rid of bulky isolation transformers, and that the filament current and, hence, the electron gun current, is controlled by a feedback circuit including a superluminescent diode decoupled from the high voltage by means of an optical fiber. This electron gun is intended for general purposes, although we have especially developed it to meet the needs of our experiment on the infrared emission spectroscopy of rare gas excimers. Our experiment requires that the charge injection into the sample is pulsed and constant and stable in time. The new electron gun can deliver several tens of nC per pulse of electrons of energy up to 100 keV into the sample cell. The new design also eliminates ripples in the emission current and ensures up to 12 h of stable performance.

Barcellan, L.; Carugno, G. [INFN Section, Padua (Italy); Berto, E.; Galet, G.; Galeazzi, G. [Department of Physics, University of Padua (Italy); Borghesani, A. F. [INFN Section, Padua (Italy); CNISM Unit, Department of Physics, University of Padua (Italy)

2011-09-15T23:59:59.000Z

488

Tunable THz Generation by the Interaction of a Super-luminous Laser Pulse with Biased Semiconductor Plasma  

SciTech Connect

Terahertz (THz) radiation is electromagnetic radiation in the range between several hundred and a few thousand GHz. It covers the gap between fast-wave electronics (millimeter waves) and optics (infrared). This spectral region offers enormous potential for detection of explosives and chemical/biological agents, non-d