| Contact Versus Noncontact Cell Electroporation |
28-May-2009 |
14 pages |
| Authors:
David French; Michael Uhler; R M Gilgenbach; Y Y Lau; MICHIGAN UNIV ANN ARBOR
|
 | In this research, experiments and simulations were performed to determine the effects of capacitive VS conductive coupling for the electroporation of cells. The experiment is performed with a fast risetime pulser to expose samples of cells to electric fields at peak voltage of 24.4 kV, 0.6 ns risetime, and 1.6 ns FWHM. Experiments performed compare the direct-conductive connection of the cell suspension versus a capacitively coupled cell suspension. The main ... |
|
| Q-Switched and Mode Locked Short Pulses from a Diode Pumped, YB-Doped Fiber Laser |
26-Mar-2009 |
115 pages |
| Authors:
Seth M Swift; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| A diode-pumped, ytterbium (Yb)-doped fiber laser system was designed and demonstrated to operate in continuous wave (cw), passively Q-switched and possibly passively mode locked operation. To our knowledge, this was the first fiber laser oscillator built at the Air Force Institute of Technology. A Cr4+:YAG (Chromium: Ytterbium Aluminum Garnett) crystal was used as a saturable absorber to generate Q-switched pulses. Attempts to mode lock the laser were performed using a ... |
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| Electrostatic Discharge Properties of Irradiated Nanocomposites |
Mar-2009 |
121 pages |
| Authors:
Joshua D McGary; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT/DEPT OF ENGINEERING PHYSICS
|
| Modernization in space systems requires employment of new light-weight, high performance composite materials that reduce bulk weight and increase structural integrity. This thesis explored the behavior of one such material prior to and following a 35-year simulated space radiation life-cycle. Select electrical properties of nickel nanostrand(TradeMark)-carbon composites in seven configurations were characterized prior to electron irradiation via surface and bulk resistivity measurements and contact electrostatic discharge (ESD) measurements. Following irradiation ... |
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| Mid-Infrared Optically Pumped, Unstable Resonator Lasers (Postprint) |
19 JUN 2007 |
5 pages |
| Authors:
A. P. Ongstad; R. Kaspi; G. C. Dente; M. L. Tilton; J. Chavez; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| The authors describe high-brightness, broad area midinfrared semiconductor lasers. These devices were fabricated in the authors laboratory using a commercial solid-source molecular beam epitaxial system. The laser structures incorporated 14 type-II quantum wells embedded in thick waveguide/ absorber regions composed of In0.2Ga0.8As0.18Sb0.82. The optically pumped devices achieved higher brightness operation as unstable resonators. Each unstable resonator was realized by polishing a diverging cylindrical mirror at one of the facets. For ... |
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| Mid-Infrared Optically Pumped, Unstable Resonator Lasers (Preprint) |
31 MAY 2007 |
13 pages |
| Authors:
A. P. Ongstad; AIR FORCE RESEARCH LAB KIRTLAND AFB NM DIRECTED ENERGY DIRECTORATE
|
| The authors describe high-brightness, broad area midinfrared semiconductor lasers. These devices were fabricated in the authors laboratory using a commercial solid-source molecular beam epitaxial system. The laser structures incorporated 14 type-II quantum wells embedded in thick waveguide/ absorber regions composed of In0.2 Ga0.8 As0.18 Sb0.82. The optically pumped devices achieved higher brightness operation as unstable resonators. Each unstable resonator was realized by polishing a diverging cylindrical mirror at one of ... |
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| High Brightness from an Unstable Resonator Mid-IR Semiconductor (Postprint) |
13 JUN 2006 |
6 pages |
| Authors:
A. P. Ongstad; G. C. Dente; M. L. Tilton; J. C. Chavez; Jr Gianardi D. M.; AIR FORCE RESEARCH LAB KIRTLAND AFB NM
|
| We describe high-brightness, broad-area mid-IR semiconductor lasers. The optically pumped devices achieved higher brightness operation as unstable resonators. Each unstable resonator was realized by polishing or etching a diverging cylindrical mirror at one of the facets. For several mid-IR unstable resonator devices experimental near- and far-fields near threshold are shown, as well as at many times threshold. For an unstable resonator semiconductor laser operating at 4.6 micrometer and at a ... |
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| Developing a Methodology for Elaborating a Pulsed Optical Safety Area for High Power Laser Diodes |
JUN 2006 |
27 pages |
| Authors:
Plamen Yankov; Y AND S COMPANY SOFIA (BULGARIA)
|
| The laser diodes are efficient sources of optical radiation. The maximum optical peak power depends on the pulse duration of the driving current pulse - reducing the pulse duration the safety peak power is increased. The aim of the study is to elaborate a methodology to determine the safety operation area of the high power laser diodes designed for CW operation. Using this methodology, the designer of certain laser devices ... |
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| Pulsed Current Static Electrical Contact Experiment |
MAY 2006 |
11 pages |
| Authors:
Harry N. Jones; Jesse M. Neri; Craig N. Boyer; Khershed P. Cooper; Robert A. Meger; NAVAL RESEARCH LAB WASHINGTON DC
|
| Railguns involve both static and sliding electrical contacts, which must transmit the large transient electrical currents necessary to impart high forces onto a projectile for acceleration to hypervelocity. Static electrical contacts between metals initially take place through small asperities, or "a-spots", distributed over the contact area. The voltage developed across the interface is directly related to the contact temperature and pressure, the number of a-spots, the thermophysical and mechanical properties ... |
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| Evaluation of 10 kV, 80 kA Si SGTO Switching Components for Army Pulsed Power Applications |
May-2006 |
5 pages |
| Authors:
Tim Crowley; Heather O'Brien; William Shaheen; Stephen B Bayne; ARMY RESEARCH LAB ADELPHI MD
|
| The U.S. Army Research Lab (ARL) is investigating the switching capabilities of advanced silicon devices for high current pulsed power applications. These solid state switches are intended to replace more traditional vacuum switches. The benefits of these switches are higher dI/dt, peak power levels and current densities, increased reliability and lifetime, and smaller switch volume. The peak current achieved by the device was 83.3 kA, with a 10% to 90% ... |
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| Pulse Discharge Characteristics of Surface Mount Capacitors |
May-2006 |
5 pages |
| Authors:
W J Carey; A J Wiebe; L L Altgilbers; W C Nunnally; ARC TECHNOLOGY WHITEWATER KS
|
| ARC Technology is developing pulse generators for extremely compact geometries requiring megawatts of power and milliJoule to Joule of total energy. These devices are to be constructed with surface mount components and circuit board fabrication techniques to minimize volume, cost, and production time. Clearly, the components in these circuits are operating well beyond their design specifications. Therefore, this paper examines the energy storage and peak power capabilities of various surface ... |
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| Evaluation of a 10 kV, 400 kA Si SGTO at High dI/dt |
May-2006 |
5 pages |
| Authors:
Heather O'Brien; William Shaheen; Stephen B Bayne; Timothy Crowley; ARMY RESEARCH LAB ADELPHI MD BERKELEY RESEARCH ASSOCIATES
|
| The evaluation of each 10 kV, 400 kA Si SGTO included a visual inspection and high-potting of each component module prior to pulsing. The complete unit was then switched in a low inductance RLC circuit to test voltage and current capabilities and maximize dI/dt. Devices were switched as many as 70 times without failure. Voltage sharing between the layers was within plus or minus 2%, and current sharing between the ... |
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| Evaluation of a 4 mm x 4 mm SiC GTO at Temperatures up to 150 degs C and Varying Pulse Width |
May-2006 |
5 pages |
| Authors:
Heather O'Brien; William Shaheen; Stephen B Bayne; ARMY RESEARCH LAB ADELPHI MD
|
| The U. S. Army Research Laboratory (ARL) is evaluating silicon carbide Super GTOs (SGTOs) [1] to determine the extent of silicon carbide's capabilities as a possible replacement for silicon in future pulsed switching applications. Individual SiC die measuring 4 mm x 4 mm were pulsed at high temperatures and varying pulse widths. These SGTOs were switched in an RLC circuit at temperatures up to 150 deg C. At this peak ... |
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| Z-Pinch Plasma Neutron Sources |
24 MAR 2006 |
54 pages |
| Authors:
A. L. Velikovich; R. W. Clark; J. Davis; Y. K. Chono; C. Deeney; C. A. Coverdale; C. Ruiz; G. Cooper; J. Franklin; L. I. Rudakov; SANDIA NATIONAL LABS ALBUQUERQUE NM
|
| A deuterium gas-puff load imploded by a multi-MA current driver, from a large initial diameter could be a powerful source of fusion neutrons, a plasma neutron source. Unlike the beam-target neutrons produced in Z-pinch plasmas in the 1950s and deuterium-fiber experiments in the 1980s, the neutrons generated in deuterium gas-puffs, with current levels achieved in recent experiments on the SNL Z facility, could contain a substantial fraction of thermonuclear origin. ... |
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| Acceleration of Dielectric Charging in RF MEMS Capacitive Switches (Preprint) |
MAR 2006 |
10 pages |
| Authors:
Xiaobin Yuan; James C. Hwang; David I. Forehand; Charles L. Goldsmith; MEMTRONICS PLANO TX
|
| To design and validate accelerated life tests of RF MEMS capacitive switches, acceleration factors of charging effects in switch dielectric were quantitatively characterized. From the measured charging and discharging transient currents at different temperatures and control voltages, densities and time constants of dielectric traps were extracted. A charging model was constructed to predict the amount of charge injected into the dielectric and the corresponding shift in actuation voltage under different ... |
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| A New Coupled Quantum Well Switching Laser (Preprint) |
MAR 2006 |
5 pages |
| Authors:
J. Cai; H. Opper; R. Bascilica; R. Garber; G. W. Taylor; OPEL INC STOORS MANSFIELD CT
|
| A new thyristor VCSEL is reported. It incorporates two independent sets of modulation-doped quantum wells. Threshold currents for 12-micrometer and 8-micrometer apertures are 2.2 mA and 1.6 mA, respectively, with corresponding peak powers of 1.7 mW and 0.16 mW. |
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| Ablation Study in a Capillary Sustained Discharge |
2006 |
11 pages |
| Authors:
Michael Keidar; Iain D. Boyd; Anthony Williams; Richard Beyer; MICHIGAN UNIV ANN ARBOR DEPT OF AEROSPACE ENGINEERING
|
| Electrothermal-chemical (ETC) ignition systems have been demonstrated in gun systems to provide desirable characteristics including reproducible shorter ignition delays. The optimum combination of capillary tube and fuse wire properties has not been identified yet. We present a combined theoretical and experimental study of the capillary discharge with an aim to develop a capillary plasma source with efficient energy conversion. The major emphasis in the present capillary discharge model is the ... |
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| No Effect of Moderate Hypohydration or Hyperthermia on Anaerobic Exercise Performance |
2006 |
6 pages |
| Authors:
S. N. Cheuvront; R. Carter; E. M. Haymes; M. N. Sawka; ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA THERMAL AND MOUNTAIN MEDICINE DIVISION
|
| Purpose: This study examined the effects of hypohydration and moderate hyperthermia (core temperature elevation) on anaerobic exercise performance in a temperate environment. Methods: Eight active males completed two passive heat exposure trials (180-min, 45 degrees C, 50%rh) with (EUH) and without (HYP) fluid replacement. A single 15-s Wingate Anaerobic Test (WAnT) was used to assess anaerobic performance (peak power, mean power, and fatigue index) before (-180-min) and again a three ... |
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| Diode Laser Efficiency Increases Enable > 400-W Peak Power From 1-cm Bars and Show Clear Path to Peak Powers in Excess of 1-kW |
2006 |
11 pages |
| Authors:
Paul Crump; Jun Wang; Steve Patterson; Damian Wise; Alex Basauri; Mark DeFranza; Sandrio Elim; Weimin Dong; Shiguo Zhang; Mike Bougher; NLIGHT PHOTONICS CORP VANCOUVER WA
|
| Peak optical power from single 1-cm diode laser bars is advancing rapidly across all commercial wavelengths. Progress in material performance is reviewed and we show that current trends imply there is no fundamental barrier to achieving peak powers of 1-kW per 1-cm diode laser bar. For bars with such high peak powers. commercially available reliable devices would be expected to deliver ~300-W per bar. Progress to date has allowed us ... |
|
| Self-Activated Micro Direct-Methanol Fuel Cell (muDMFC) at Near Room Temperature |
15 JUN 2005 |
53 pages |
| Authors:
|
| This research project was focused on the development and testing of Micro Direct-Methanol Fuel Cells (Micro DMFC). A Si-based Micro DMFC was developed and its electrochemical characteristics studied. The peak power density reached 50 mW/sq cm at 60 deg C. A new MEA design was successfully developed to mitigate MeOH crossover without requiring novel membranes. A Micro DMFC was also fabricated by using photochemically etched stainless steel bipolar plates and ... |
|
| A Counterpulsed, Solid-State Opening Switch |
JUN 2005 |
48 pages |
| Authors:
Michael Graham; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Railguns have great potential in military roles; however, they currently lack a fieldable power supply. Recent advances in the state of low voltage power storage devices may enable practical Pulse Forming Inductive Network power supplies to be developed if a suitable current interruption device is developed. A solid-state device in a counterpulsed opening switch configuration is a possible solution. A demonstration counterpulsed solid-state opening switch was constructed and successfully tested. ... |
|
| Renewable Energy Analysis For Strategic Responsiveness 3 (REASR 3) |
JUN 2005 |
65 pages |
| Authors:
Hugh W. Jones; CENTER FOR ARMY ANALYSIS FORT BELVOIR VA
|
| Army installations require electric power to perform the missions assigned to them whether or not the power is used at the main post or at remote locations at the installation. Providing electric power to the main post is accomplished through the local electric company. However, for remote locations the usual source of electric power is diesel generated 1.5 kW to 200 kW power from generators using diesel fuel as the ... |
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| Cellular, Molecular Signaling and Genetic Alterations After High-Peak Power Pulsed and Ultrawideband Radio Frequency Radiation Exposure |
22 FEB 2005 |
21 pages |
| Authors:
Martin L. Meltz; Bijaya Nayak; Mohan Natarajan; TEXAS UNIV HEALTH SCIENCE CENTER AT SANANTONIO
|
| The most significant finding occurred after exposure of human 244B lymphoblastoid cells to a high-peak power pulsed ultrawideband transmitted electric field (UWB TEMF) signal, which had given a wide array of largely negative results. The UWB TEMF exposure (average peak power, 100 kV/m; average pulse width, 780 ps) duration was 90 min (intermittent). The UWB TEMF did not cause an alteration in cell cycle distribution, stabilization of the p53 target ... |
|
| High Efficiency Class-F MMIC Power Amplifiers at Ku-Band |
2005 |
5 pages |
| Authors:
Matthew T. Ozalas; MITRE CORP BEDFORD MA
|
| Two high efficiency Ku-band pHEMT power amplifier MMICs are presented in this paper. A single, stage, high efficiency amplifier provides a peak power added efficiency of 57.6% with 10.5 dB associated gain and 26.5 dBm output power into a 50 Ohms load at 14 GHz. Additionally, a dual stage, high gain amplifier provides a peak power added efficiency of 50.4% with 19.7 dB associated gain and 27.5 dBm output power ... |
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| Novel THz-Frequency Spectrometers by Integrating Widely-Tunable Monochromatic THz Sources and Detectors, or Arrays of Emitters and Detectors, with Photonic Bandgap Crystals |
16 NOV 2004 |
10 pages |
| Authors:
Yuliya B. Zotova; ARKLIGHT CENTER VALLEY PA
|
| We have successfully carried out our Phase-I research by achieving most of the Phase-I objectives. First, we have significantly extended the tuning range of our THz source and increased the output peak powers. Second, we have used our tunable THz source to measure the absorption spectra of several chemicals in the vapor phase, and therefore, we have demonstrated the feasibility of fingerprinting molecules. Third, we have used our tunable THz ... |
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| Terahertz Devices: Tunable and Mode-Locked p-Ge THz Laser |
05 MAY 2004 |
11 pages |
| Authors:
J. Fredricksen; R. E. Peale; ZAUBERTEK INC ORLANDO FL
|
| This Phase II STTR project developed and demonstrated a corn pact, turn-key, cryogen-free, p-type germanium laser, tunable over the range 1.5A.2 THz (70-200 micron wavelength), with I Watt peak power. A new type of intracavity gain modulator with potential application to active mode locking was discovered. improvement in the gain of the active p-Ge crystal by homogeneous neutron transmutation doping was experimentally shown. An alternative means of gain improvement, which ... |
|
| Barrel Wear Reduction in Rail Guns: An Investigation of Silver Paste Liquid-Metal Interface |
DEC 2002 |
62 pages |
| Authors:
Michael W. Smith Jr; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis tests the effects a commercial silver paste has on the damage at the projectile-rail interface of a 4" long rail gun test section. Projectiles (0.635 x 0.635 x 0.953 cm) were pushed through the rail test section at 34 plus or minus 19 m/s, while average current densities of 18 - 32 kA/cm2 was passed through the projectile - rail interface material. The specific objective is to examine ... |
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| PAVE PAWS Radiation Decays Exponentially in Lossy Materials |
09 SEP 2002 |
54 pages |
| Authors:
Thomas Roberts; AIR FORCE RESEARCH LAB HANSCOM AFB MA SENSORS DIRECTORATE
|
| Dr. Rick Jostes asked me to give a talk for a National Research Council committee that is investigating aspects of a phased-array radar named PAVE PAWS. Dr. Jostes suggested that I discuss the relation of statements by Prof. Kurt Oughstun to my recent work on exponential decay of radiation in lossy materials. With that incentive, I found that most of the 88-years' of precursor literature is irrelevant to PAVE PAWS. ... |
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| A Gyrotron-Traveling-Wave Tube Amplifier Experiment with a Ceramic Loaded Interaction Region |
JUN 2002 |
|
| Authors:
Morag Garven; Jeffrey P. Calame; Bruce G. Danly; Khanh T. Nguyen; Baruch Levush; NAVAL RESEARCH LAB WASHINGTON DC VACUUM ELECTRONICS BRANCH
|
 | The design and experimental study of a 35-GHz gyrotron-traveling-wave tube (gyro-TWT) amplifier operating in the circular TE01 mode at the fundamental cyclotron harmonic are presented. The interaction circuit in this experiment consisted of a new type of ceramic loading that provided the required loss for stable operation. A saturated peak power of 137 kW was measured at 34.1 GHz, corresponding to a saturated gain of 47.0 dB and an efficiency ... |
|
| Semiconductor Laser for the 2-5 Micrometers and 7-9 Micrometers Region/ Quantum Cascade Lasers |
JUN 2002 |
12 pages |
| Authors:
M. Razeghi; S. Slivken; Z. Huang; A. Evans; NORTHWESTERN UNIV EVANSTON IL CENTER FOR QUANTUM DEVICES
|
| The quantum cascade laser is one of the strong candidates for a portable mid-infrared light source for a variety of DoD applications We have seen dramatic improvements in high temperature performance at long wavelengths, including threshold current densities as low as 1.4 kA/cm(2) and peak power outputs greater than 7 W for a single 20 mm aperture. Along with the significant design improvements, we have also demonstrated laser operation at ... |
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| Radiated Pulses Decay Exponentially in Materials in the Far Fields of Antennas |
28 FEB 2002 |
3 pages |
| Authors:
Thomas M. Roberts; AIR FORCE RESEARCH LAB HANSCOM AFB MA SENSORS DIRECTORATE
|
| There has been recent interest in using short-pulse radar to detect targets in lossy clutter. The analysis presented here shows that the energy and peak-power densities of pulses decay exponentially with depth in homogeneous, lossy, dispersive materials, provided the frequency bands of the pulses are separated from DC. Many numerical examples verify the analytical results. |
|
| Barrier Roughness Effects in Resonant Interband Tunnel Diodes |
15 DEC 2001 |
6 pages |
| Authors:
R. Magno; A. S. Bracker; B. R. Bennett; B. Z. Nosho; L. J. Whitman; NAVAL RESEARCH LAB WASHINGTON DC PLASMA PHYSICS DIV
|
| Peak current densities of InAs/AlSb/GaSb/AlSb/InAs resonant interband tunneling diodes (RITD) grown by molecular beam epitaxy have been measured as a function of the growth temperature. The growth procedures were designed to produce nominally identical AlSb tunneling barriers. The variations observed in the peak current for positive bias are consistent with the barrier on the substrate side of the RITD becoming effectively thicker for diodes grown at high temperatures. Plan-view in ... |
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| Resonant Interband Tunnel Diodes with AlGaSb Barriers |
15 MAY 2001 |
|
| Authors:
R. Magno; A. S. Bracker; B. R. Bennett; NAVAL RESEARCH LAB WASHINGTON DC
|
| The peak current density of InAs/AlSb/GaSb/AlSb/InAs resonant interband tunneling diodes (RITDs) has been enhanced by replacing the AlSb barriers with Al(1-x)Ga(x)Sb that has a narrower band gap. The devices were grown by molecular beam epitaxy and tested at room temperature. Diodes with nominally identical 7-ML-thick ternary alloy barriers with x=0.35 are found to have peak current densities three times larger than those with AlSb barriers. The peak-to-valley current ratio decreases ... |
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| Proton Irradiation of InAs/AlSb/GaSb Resonant Interband Tunneling Diodes |
23 APR 2001 |
|
| Authors:
R. Magno; B. D. Weaver; A. S. Bracker; B. R. Bennett; NAVAL RESEARCH LAB WASHINGTON DC
|
| Room temperature current voltage measurements have been made on InAs/AlSb/GaSb resonant interband tunnel diodes (RITDs) irradiated with 2 MeV protons to determine the effect of displacement damage on the negative resistance peak current I(sub p) and the peak-to-valley current ratio P/V. Diodes with 5 and 13 ML AlSb barrier thickness were irradiated and measured several times until the total fluences reached 1 x 10(exp 15) and 2 x 10(exp 14) ... |
|
| Design of a Ka-Band Gyro-TWT for Radar Applications |
JAN 2001 |
|
| Authors:
Khanh T. Nguyen; Jeffrey P. Calame; Dean E. Pershing; Bruce G. Danly; Morag Garven; NAVAL RESEARCH LAB WASHINGTON DC VACUUM ELECTRONICS BRANCH
|
| The design of a Ka-band gyrotron traveling wave tube (TWT) amplifier capable of operating over a wide range of peak powers and bandwidths is presented. The amplifier operates in the TE11 mode at the fundamental cyclotron harmonic. Instantaneous bandwidths in the range of 2.5 to 3.9 GHz (at 1 dB below saturation) with corresponding peak powers between 92.2 and 57.9 kW can be achieved by simply adjusting the mod-anode voltage ... |
|
| Fourier Transform THz-Wave Spectrometer Using THz-Wave Parametric Generator |
29 SEP 2000 |
4 pages |
| Authors:
Jun-ichi Shikata; Kodo Kawase; Tetsuo Taniuchi; Hiromasa Ito; TOHOKU UNIV SENDAI (JAPAN) RESEARCH INST OF ELECTRICAL COMMUNICATION
|
| We have developed a THz-wave spectrometer with the combination of a bright THz-wave source of THz-wave parametric generator (TPG) and a Martin- Puplett interferometer. The TPG output was optimized by studying various configurations with LiNbO3 crystals. THz-waves which span the 1-2THz region were emitted with the peak power of 280 micro W. The whole system, including the nitrogen-purge unit, was constructed in a table-top size. By use of the THz-wave ... |
|
| Reliable, Intense, Ultrafast and Compact Guided-Wave Laser for Cloud Penetration, Remote Sensing, and Active Imaging |
SEP 2000 |
46 pages |
| Authors:
Philippe Bado; CLARK-MXR INC DEXTER MI
|
| The goal of this program is to develop reliable, ultrafast, high peak-power lasers. These lasers will be used in the military for cloud penetration, reconnaissance, remote sensing, and active illumination; in the microelectronic industry for repair of photomasks and for memory yield improvement; in the automotive industry for sensors and fuel injector machining; and in the aerospace industry for turbine blade machining. We met all of our Phase I objectives. ... |
|
| Herriott Cell Interferometer for Density Measurements in Small-Scale Length Plasmas |
JUN 2000 |
21 pages |
| Authors:
Erik Antonsen; Rodney Burton; Scott Engelman; Greg Spanjers; ILLINOIS UNIV AT URBANA-CHAMPAIGN SAVOYAVIATION RESEARCH LAB
|
| The introduction of a Herriott cell into a standard quadrature heterodyne interferometer is evaluated and demonstrated to increase the resolution of the system. Measurements of electron and neutral density during and after the current pulse are sought for modeling purposes for spacecraft contamination from Pulsed Plasma Thrusters. Testing is performed on the UIUC PPT-4, a coaxial electrothermal Pulsed Plasma Thruster pulsing at 20 J. Analytical and experimental analysis is conducted ... |
|
| Global/Local Design Optimization of A Power Distribution System |
31 MAR 2000 |
27 pages |
| Authors:
Zafer Gurdal; Scott Ragon; Douglas Lindner; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF ENGINEERING SCIENCE AND MECHANICS
|
| A mathematical optimization technique is used to design several components of a power distribution system for next generation aircraft. A simple interconnected system consisting of an input filter and a DC-Dc buck converter is used as the prototype for the optimization demonstration. The components are designed for minimum weight subject to performance, stability, and peak voltage constraints. Optimized designs for each of the individual subsystems and for the integrated system ... |
|
| Electrical Properties and Power Considerations of a Piezoelectric Actuator |
FEB 2000 |
9 pages |
| Authors:
T. Jordan; Z. Ounaies; J. Tripp; P. Tcheng; INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA
|
| This paper assesses the electrical characteristics of piezoelectric wafers for use in aeronautical applications such as active noise control in aircraft. Determination of capacitive behavior and power consumption is necessary to optimize the system configuration and to design efficient driving electronics. Empirical relations are developed from experimental data to predict the capacitance and loss tangent of a PZT5A ceramic as nonlinear functions of both applied ... |
|
| First Stroke Peak Current Characteristics for the United States |
06 OCT 1999 |
290 pages |
| Authors:
Gary Russell Huffines; TEXAS A AND M UNIV COLLEGE STATION
|
| The first stroke peak currents of over 105 million cloud to ground lightning flashes from 1995-1998 were analyzed over the continental Unites States (U.S.) landmass. The peak currents exhibit a variation based on season and geography, but positive flashes have different features than negative flashes. Several factors are considered when examining the peak current variations including latitudinal dependence, sensor separation in the National Lightning ... |
|
| Data Fusion in Large Arrays of Microsensors (Sensorweb) |
SEP 1999 |
6 pages |
| Authors:
John Lavery; ARMY RESEARCH OFFICE RESEARCH TRIANGLEPARK NC
|
| Distributed sensing by organized or self-organizing arrays of large numbers of geographically dispersed miniature sensors of various modalities is increasingly recognized as a key to battlefield surveillance. To date, research on data fusion in distributed sensing has often neglected physical constraints, including those on energy reserves, bandwidth, latency, processing capability and peak transmitter power. Fundamental limitations on data fusion and optimal strategies within these limitations, even under relative mild assumptions, ... |
|
| Progress in Red Vertical Cavity Surface Emitting Lasers |
18 JUN 1999 |
6 pages |
| Authors:
J. A. Lott; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH
|
| The development of red vertical cavity surface emitting lasers with peak emission wavelengths from 620 tn 690 nm is reviewed. The performance characteristics of state-of-the-art gain guided and selectively oxidized device structures are presented. |
|
| Anti-Ship Missile Defense and the Free Electron Laser |
DEC 1998 |
80 pages |
| Authors:
Paul A. Herbert; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| In order to improve ship self-defense against sea-skimming missiles, several concepts, such as the free electron laser, high-power microwaves, and the Phalanx gun system are reviewed and evaluated in this thesis. Phalanx computer simulations show that Phalanx is an inadequate means of protection. High-power microwaves are found to damage electronics, but calculations show limitations due to diffraction and the possibility of shielding. This thesis evaluates several damage mechanisms caused by ... |
|
| Subtle Measurement of Behavior Effects of Microwave Radiation |
NOV 1998 |
34 pages |
| Authors:
John Ziriax; OPERATIONAL TECHNOLOGIES CORP SAN ANTONIO TX
|
| The growing application of microwave (RF) technology has increased the potential for hazardous human exposures. The potential hazard posed by this expanding use of RF technology requires an ongoing study of RF bioeffects to keep pace with new applications and technologies. Furthermore, exposures to new and future sources are likely to involve RF power levels and exposure parameters (e.g., frequency, pulse width, peak power, etc.) which ... |
|
| A Comparative Analysis of Total Lighting Observations and Cloud-to-CloudLighting Observations in the Southeastern United States Region |
27 OCT 1998 |
97 pages |
| Authors:
Keith M. Hugo; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH
|
| A comparison was performed employing lightning data collected by the Optical Transient Detector (OTD) satellite and the National Lightning Detection Network (NLDN). The feasibility of using total lightning flash data, both intracloud (IC) and cloud-to-ground (CG), collected from the OTD satellite in conjunction with CG lightning flashes detected by the NLDN was demonstrated. The IC and CG lightning flashes were determined for the period from 1 ... |
|
| Method for Launching Projectiles with Hydrogen Gas. |
04 AUG 1998 |
|
| Authors:
Woodrow W. Lee; Richard D. Ford; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A method for propelling a projectile by applying a high power pulse of electrical current to a metal fuel element (of Al. Al-Li, or Al-Mg) causing the element to explode dispersing molten metal fuel into water with which it reacts to rapidly generate hydrogen gas at high pressure, the hydrogen gas is used to push the projectile. After the peak current is reached, an inductive electrical energy source drives the ... |
|
| Nd:YLF Laser System for the Study of Termolecular Reactions and Metastable Isomers of Polyatomic Molecules |
31 DEC 97 |
4 pages |
| Authors:
Robert E. Continetti; CALIFORNIA UNIV SAN DIEGO LA JOLLA DEPT OF CHEMISTRY
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| The DURIP grant F49620-97-1-0255 has supported acquisition of a state-of-the-art regeneratively amplified Ti:Sapphire laser system. This laser system is the primary laser for our new multi-particle photoelectron photofragment coincidence spectrometer, and is currently being used to carry out experiments on three-body dissociation dynamics in clusters of oxygen and ozone. These experiments make use of a new particle detector built in our laboratory capable of recording the ... |
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| Compound-Cavity, High-Power, Modelocked Semiconductor Laser. |
OCT 1996 |
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| Authors:
Lew Goldberg; DEPARTMENT OF THE NAVY WASHINGTON DC
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| The invention is for a new type of an efficient and compact laser system, based on semiconductor gain medium, which produces high peak power. The laser system comprises: a compound cavity laser defined by first and second reflective elements; a developing structure, having a first end containing the first reflective element and a second end, being disposed in the compound cavity laser and being responsive to an RF frequency signal ... |
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| (AASERT-93), Tailored Group Velocity Dispersion Using Periodic Structures |
26 AUG 96 |
77 pages |
| Authors:
Kamil Agi; Kevin J. Malloy; NEW MEXICO UNIV ALBUQUERQUE CENTER FOR HIGH TECHNOLOGY MATERIALS
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| Photonic crystals are three- or lower-dimensional dielectric structure that exhibits overlapping stop bands in all directions. The focus of this work has been the design and characterization of a novel face-centered- cubic photonic crystal. The characterization was done in four parts. The first was a simple microwave network analyzer measurement where horn antennas were used transmit and receive CW microwave radiation. The second characterization was a direct time-domain characterization using ... |
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| Inverted Optical Modulators for Communications Networks |
JUL 96 |
31 pages |
| Authors:
N. Peyghambarian; ARIZONA BOARD OF REGENTS TUCSON
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| The design and fabrication of a Kerr Lens Modelocked (KLM) chromium- doped forsterite laser is described. The KLM forsterite laser allows the study of ultrafast optical and electronic properties of materials in the near-IR with femtosecond time resolution. In particular, the laser produces sub-200 femtosecond pulses (tunable between 1240 and 1285 nm) with 2 kw of peak power at a 93 MHz repetition rate. The KLM forsterite laser was used ... |
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