Science.gov

Sample records for 1-2 ghz system

  1. Low Cost 1.2 to 116 GHz Receivers for the ngVLA

    NASA Astrophysics Data System (ADS)

    Weinreb, Sander; Soliman, Ahmed; Mani, Hamdi

    2017-01-01

    The next-generation VLA (ngVLA) is a major new radio telescope that is being considered for implementation is the southwest US in the 2020 decade. The general parameters which have been discussed in science and technology workshops in the past 18 months are an array with 10 times the sensitivity and resolution of the current JVLA and operating in the 1.2 to 116 GHz range which is the approximate frequency gap between the SKA and ALMA. This can be implemented with 256 x 18m antennas at fixed locations within a 300km maximum baseline.A major requirement for this instrument is affordable capital and operating cost. This poster addresses a receiver design to minimize these costs. A goal is an operating cost no larger than the current JVLA. An important parameter in the operating cost both for electric power and maintenance is the number of cryogenic coolers and vacuum dewars. The JVLA has 8 such systems on 27 telescopes and our goal is 1 cryogenic dewar on each of the 256 telescopes to give approximately the same total number of cryogenic systems.Key questions are the number and frequency range of the receivers packaged as one system. Much work has been done in the past several years on wideband antenna feeds and low noise amplifiers and the important question is the sensitivity as measured by effective area divided by system noise compared to this figure of merit for narrow band receivers. We consider that the 70-116 GHz range will be covered by one conventional bandwidth receiver, the 50 to 70 GHz range range will be skipped due to atmospheric oxygen absorption, and 1.2 to 50 GHz will be covered by 3 to 5 receivers depending upon performance studies and science needs.This poster presents constraints on the reflector shaped Gregorian optics to allow the feeds to be completely cooled in one package, possible layout of the cryogenic dewar, cooling power requirements, and a current estimate of performance.

  2. 10-GHz 1:2 switch MMIC for the communication and radar applications

    NASA Astrophysics Data System (ADS)

    Mokerov, V. G.; Gnatyuk, D. L.; Nalbandov, B. G.; Ovcharenko, E. N.; Lisitskii, A. P.

    2004-05-01

    Advances in microwave electronics result in development of more and more sophisticated devices. For all complicated microwave systems it is necessary to have the switch of the signals. It refers to the transceivers, the multi-channel systems, the control systems and many other civil and military applications. In this article the development of the 10 GHz 1:2 switch for use in the communication and radar systems is reported. Switch is designed for realization as MMIC on GaAs heterostructure substrates. It incorporates a hybrid design with directional couplers. As variable impedance elements, the field effect transistors, connected to the directional coupler arms in parallel to the channel, are used. Tuning and optimization of the circuit was performed using Microwave Office software by Applied Wave Research, Inc.

  3. 1.2-GHz gated single-photon detector with simple filtering

    NASA Astrophysics Data System (ADS)

    Liu, Junliang; Zhang, Chunfang; Li, Yongfu; Wang, Zuqiang

    2014-10-01

    A 1.2-GHz gated infrared single-photon detector based on InGaAs/InP avalanche photodiode (APD) is designed. The APD is working in Geiger mode, gated by 1.2-GHz pseudo-sine wave signal, cooled by a 4-stage Peltier cooler with fancooling. A group of simple 9th order Bessel LC low-pass filters are used to suppress the transient response of the APD by 60 dB. The typical detection efficiency, dark-count probability and afterpulse probability of the detector were 15.1%, 3.76×10-6 /gate and 1.26%, respectively. The detector is based on commercially available inexpensive devices and can be manufactured easily.

  4. 600-GHz Electronically Tunable Vector Measurement System

    NASA Technical Reports Server (NTRS)

    Dengler, Robert; Maiwald, Frank; Siegel, Peter

    2007-01-01

    A compact, high-dynamic-range, electronically tunable vector measurement system that operates in the frequency range from approximately 560 to approximately 635 GHz has been developed as a prototype of vector measurement systems that would be suitable for use in nearly-real-time active submillimeter-wave imaging. As used here, 'vector measurement system" signifies an instrumentation system that applies a radio-frequency (RF) excitation to an object of interest and measures the resulting amplitude and phase response, relative to either the applied excitatory signal or another reference signal related in a known way to applied excitatory signal.

  5. 47 CFR 101.525 - 24 GHz system operations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false 24 GHz system operations. 101.525 Section 101.525 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES 24 GHz Service and Digital Electronic Message Service § 101.525 24 GHz...

  6. 47 CFR 101.525 - 24 GHz system operations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false 24 GHz system operations. 101.525 Section 101.525 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES 24 GHz Service and Digital Electronic Message Service § 101.525 24 GHz...

  7. 47 CFR 101.525 - 24 GHz system operations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false 24 GHz system operations. 101.525 Section 101.525 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES 24 GHz Service and Digital Electronic Message Service § 101.525 24 GHz...

  8. 47 CFR 101.525 - 24 GHz system operations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false 24 GHz system operations. 101.525 Section 101.525 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES 24 GHz Service and Digital Electronic Message Service § 101.525 24 GHz...

  9. 47 CFR 101.525 - 24 GHz system operations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false 24 GHz system operations. 101.525 Section 101.525 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES 24 GHz Service and Digital Electronic Message Service § 101.525 24 GHz...

  10. The 94 GHz MMW imaging radar system

    NASA Technical Reports Server (NTRS)

    Alon, Yair; Ulmer, Lon

    1993-01-01

    The 94 GHz MMW airborne radar system that provides a runway image in adverse weather conditions is now undergoing tests at Wright-Patterson Air Force Base (WPAFB). This system, which consists of a solid state FMCW transceiver, antenna, and digital signal processor, has an update rate of 10 times per second, 0.35x azimuth resolution and up to 3.5 meter range resolution. The radar B scope (range versus azimuth) image, once converted to C scope (elevation versus azimuth), is compatible with the standard TV presentation and can be displayed on the Head Up Display (HUD) or Head Down Display (HDD) to aid the pilot during landing and takeoff in limited visibility conditions.

  11. The 30/20 GHz communications system functional requirements

    NASA Technical Reports Server (NTRS)

    Siperko, C. M.; Frankfort, M.; Markham, R.; Wall, M.

    1981-01-01

    The characteristics of 30/20 GHz usage in satellite systems to be used in support of projected communication requirements of the 1990's are defined. A requirements analysis which develops projected market demand for satellite services by general and specialized carriers and an analysis of the impact of propagation and system constraints on 30/20 GHz operation are included. A set of technical performance characteristics for the 30/20 GHz systems which can serve the resulting market demand and the experimental program necessary to verify technical and operational aspects of the proposed systems is also discussed.

  12. Advanced system characterizes antennas to 65 GHz

    NASA Astrophysics Data System (ADS)

    Francis, Michael H.; Kremer, Douglas P.; Repjar, Andrew G.

    1990-03-01

    The antenna measurement service offered by the National Institute of Standards and Technology provides radiation-pattern, on-axis gain, and polarization measurements to 65 GHz using planar near-field and extrapolation techniques. It is pointed out that measurements of millimeter-wave antennas are both difficult and costly to make and that such measurements require low-noise, high-power signal sources and exceptionally stable and repeatable connections. The process of the three-antenna extrapolation technique and subsequent measurements of dual-port circularly polarized antennas and swept-frequency gain measurements are analyzed, and antenna standards are noted. Insertion-loss measurements and attenuator calibration are discussed, and measurement uncertainties and far-field patterns are analyzed.

  13. Single-Chip T/R Module for 1.2 GHz

    NASA Technical Reports Server (NTRS)

    Moussessian, Alina; Mojarradi, Mohammad; Johnson, Travis; Davis, John; Grigorian, Edwin; Hoffman, James; Caro, Edward; Kuhn, William

    2006-01-01

    A single-chip CMOS-based (complementary-metal-oxide-semiconductorbased) transmit/receive (T/R) module is being developed for L-band radar systems. Previous T/R module implementations required multiple chips employing different technologies (GaAs, Si, and others) combined with off-chip transmission lines and discrete components including circulators. The new design eliminates the bulky circulator, significantly reducing the size and mass of the T/R module. Compared to multi-chip designs, the single-chip CMOS can be implemented with lower cost. These innovations enable cost-effective realization of advanced phased array and synthetic aperture radar systems that require integration of thousands of T/R modules. The circulator is a ferromagnetic device that directs the flow of the RF (radio frequency) power during transmission and reception. During transmission, the circulator delivers the transmitted power from the amplifier to the antenna, while preventing it from damaging the sensitive receiver circuitry. During reception, the circulator directs the energy from the antenna to the low-noise amplifier (LNA) while isolating the output of the power amplifier (PA). In principle, a circulator could be replaced by series transistors acting as electronic switches. However, in practice, the integration of conventional series transistors into a T/R chip introduces significant losses and noise. The prototype single-chip T/R module contains integrated transistor switches, but not connected in series; instead, they are connected in a shunt configuration with resonant circuits (see figure). The shunt/resonant circuit topology not only reduces the losses associated with conventional semiconductor switches but also provides beneficial transformation of impedances for the PA and the LNA. It provides full singlepole/ double-throw switching for the antenna, isolating the LNA from the transmitted signal and isolating the PA from the received signal. During reception, the voltage on

  14. The 20/30 GHz satellite systems technology needs assessment

    NASA Technical Reports Server (NTRS)

    Stevens, G.; Wright, D.

    1978-01-01

    Rain attenuation in the 20/30 GHz bands, and the resultant impact on system user costs were estimated for a variety of satellite communication system concepts. Results of previous and current NASA Lewis contractual and in-house studies on system design are reported as well as market studies conducted to evaluate the concepts and test their relevancy against forecasted market needs. The 20/30 GHz bands appear attractive economically and, with certain technology, appear to offer a virtually unlimited spectrum resource. This attractiveness is especially relevant to high density trunking where there is sufficient traffic to justify dual-station site diversity.

  15. Characterization of a 300-GHz Transmission System for Digital Communications

    NASA Astrophysics Data System (ADS)

    Hudlička, Martin; Salhi, Mohammed; Kleine-Ostmann, Thomas; Schrader, Thorsten

    2017-08-01

    The paper presents the characterization of a 300-GHz transmission system for modern digital communications. The quality of the modulated signal at the output of the system (error vector magnitude, EVM) is measured using a vector signal analyzer. A method using a digital real-time oscilloscope and consecutive mathematical processing in a computer is shown for analysis of signals with bandwidths exceeding that of state-of-the-art vector signal analyzers. The uncertainty of EVM measured using the real-time oscilloscope is open to analysis. Behaviour of the 300-GHz transmission system is studied with respect to various modulation schemes and different signal symbol rates.

  16. Modeling of NASA's 30/20 GHz satellite communications system

    NASA Technical Reports Server (NTRS)

    Kwatra, S. C.; Maples, B. W.; Stevens, G. A.

    1984-01-01

    NASA is in the process of developing technology for a 30/20 GHz satellite communications link. Currently hardware is being assembled for a test transponder. A simulation package is being developed to study the link performance in the presence of interference and noise. This requires developing models for the components of the system. This paper describes techniques used to model the components for which data is available. Results of experiments performed using these models are described. A brief overview of NASA's 30/20 GHz communications satellite program is also included.

  17. System calibration of the 1.4 GHz and 5 GHz radiometers for soil moisture remote sensing

    NASA Technical Reports Server (NTRS)

    Wang, J.; Shiue, J.; Gould, W.; Fuchs, J.; Hirschmann, E.; Glazar, W.

    1980-01-01

    Two microwave radiometers at the frequencies of 1.4 GHz and 5 GHz were mounted on a mobile tower and used for a remote sensing of soil moisture experiment at a Beltsville Agriculture Research Center test site. The experiment was performed in October 1979 over both bare field and fields covered with grass, soybean, and corn. The calibration procedure for the radiometer systems which forms the basis of obtaining the final radiometric data product is described. It is estimated from the calibration results that the accuracy of the 1.4 GHz radiometric measurements is about + or - 3 K. The measured 5 GHz brightness temperatures over bare fields with moisture content greater than 10 percent by dry weight are about 8 K lower than those taken simultaneously at 1.4 GHz. This could be due to either (1) a 5 GHz antenna side lobe seeing the cold brightness of the sky, or (2) the thermal microwave emission from a soil being less sensitive to surface roughness at 5 GHz than at 1.4 GHz.

  18. Passive 350 GHz Video Imaging Systems for Security Applications

    NASA Astrophysics Data System (ADS)

    Heinz, E.; May, T.; Born, D.; Zieger, G.; Anders, S.; Zakosarenko, V.; Meyer, H.-G.; Schäffel, C.

    2015-10-01

    Passive submillimeter-wave imaging is a concept that has been in the focus of interest as a promising technology for personal security screening for a number of years. In contradiction to established portal-based millimeter-wave scanning techniques, it allows for scanning people from a distance in real time with high throughput and without a distinct inspection procedure. This opens up new possibilities for scanning, which directly address an urgent security need of modern societies: protecting crowds and critical infrastructure from the growing threat of individual terror attacks. Considering the low radiometric contrast of indoor scenes in the submillimeter range, this objective calls for an extremely high detector sensitivity that can only be achieved using cooled detectors. Our approach to this task is a series of passive standoff video cameras for the 350 GHz band that represent an evolving concept and a continuous development since 2007. Arrays of superconducting transition-edge sensors (TES), operated at temperatures below 1 K, are used as radiation detectors. By this means, background limited performance (BLIP) mode is achieved, providing the maximum possible signal to noise ratio. At video rates, this leads to a temperature resolution well below 1 K. The imaging system is completed by reflector optics based on free-form mirrors. For object distances of 5-25 m, a field of view up to 2 m height and a diffraction-limited spatial resolution in the order of 1-2 cm is provided. Opto-mechanical scanning systems are part of the optical setup and capable of frame rates of up to 25 frames per second.

  19. MIMO based 3D imaging system at 360 GHz

    NASA Astrophysics Data System (ADS)

    Herschel, R.; Nowok, S.; Zimmermann, R.; Lang, S. A.; Pohl, N.

    2016-05-01

    A MIMO radar imaging system at 360 GHz is presented as a part of the comprehensive approach of the European FP7 project TeraSCREEN, using multiple frequency bands for active and passive imaging. The MIMO system consists of 16 transmitter and 16 receiver antennas within one single array. Using a bandwidth of 30 GHz, a range resolution up to 5 mm is obtained. With the 16×16 MIMO system 256 different azimuth bins can be distinguished. Mechanical beam steering is used to measure 130 different elevation angles where the angular resolution is obtained by a focusing elliptical mirror. With this system a high resolution 3D image can be generated with 4 frames per second, each containing 16 million points. The principle of the system is presented starting from the functional structure, covering the hardware design and including the digital image generation. This is supported by simulated data and discussed using experimental results from a preliminary 90 GHz system underlining the feasibility of the approach.

  20. 39 GHz Interferometer System for Measuring Detonation Velocity

    SciTech Connect

    Ross, Patrick W.; Tran, Vu; Waltman, Thomas B.; Tringe, Joe; May, Chadd; Cradick, Jerry; Hodgin, Ralph; Kane, Ron

    2015-05-13

    A new 39 GHz RF interferometer system is presented for use in velocity measurements of high explosives (HE) detonations. The frequency was chosen to compliment the currently available suite, and provide more spatial information. An RF signal is generated and coupled to a waveguide adapter serving as an antenna. The HE is initially transparent to the RF. When the HE detonates, the detonation front becomes reflective to the RF. This reflection is picked up by the waveguide adapter and mixed with an unperturbed RF signal to give a low frequency signal which can be digitized with an oscilloscope. By comparing the signal with a reference signal, velocity information can be obtained using Fourier Transforms and wavelet models. Bench test results using a “slapper” are shown. The 39 GHz microwave interferometer is used in Deflagration to Detonation shots. The signal is reflected off a moving surface, and the Doppler shift of the reflected signal is used to calculate the velocity.

  1. Few-hundred GHz carbon nanotube nanoelectromechanical systems (NEMS).

    PubMed

    Island, J O; Tayari, V; McRae, A C; Champagne, A R

    2012-09-12

    We study 23-30 nm long suspended single-wall carbon nanotube quantum dots and observe both their stretching and bending vibrational modes. We use low-temperature DC electron transport to excite and measure the tubes' bending mode by making use of a positive feedback mechanism between their vibrations and the tunneling electrons. In these nanoelectromechanical systems (NEMS), we measure fundamental bending frequencies f(bend) ≈ 75-280 GHz and extract quality factors Q ∼ 10(6). The NEMS's frequencies can be tuned by a factor of 2 with tension induced by mechanical breakjunctions actuated by an electrostatic force or tension from bent suspended electrodes.

  2. The 18/30 GHz fixed communications system service demand assessment. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Gabriszeski, T.; Reiner, P.; Rogers, J.; Terbo, W.

    1979-01-01

    The total demand for voice, video, and data communications services, and satellite transmission services at the 4/6 GHz, 12/14 GHz, and 18/30 GHz frequencies is discussed. Major study objectives, overall methodology, results, and general observations about a satellite systems market characteristics and trends are summarized.

  3. A 35 GHz vector system for non destructive applications

    NASA Astrophysics Data System (ADS)

    Glay, D.; Lasri, T.; Mamouni, A.; Leroy, Y.

    2000-05-01

    It has been demonstrated that microwave techniques are well suited for nondestructive testing (NDT) of materials. The challenge now is to propose systems that can compete, in terms of reliability, precision and fabrication cost, with those already existing. Microwaves are expected to play a fundamental role if we are able to develop both methods and systems to fulfill the increasing demand of characterization in this dynamic field. We have developed devices operating at 2.45 and 10 GHz that have been used successfully for layer thickness and material parameters (permittivity, moisture,…) measurement. In order to tackle other problems met by the NDT community, that need to operate at higher frequencies we have conceived a sensor for the determination of the material under test reflection coefficient (magnitude and phase) at 35 GHz. This system conceived around a complex correlator (or IQ demodulator), made in microstrip technology, is used for the detection of flaws inside dielectric materials or on surface conductors. These investigations concern defects with various shapes, sizes, and dielectric properties.

  4. Modeling Results for Proposed NSTX 28 GHz and EBWH System

    SciTech Connect

    Taylor, G; Ellis, R A; Fredd, E; Greenough, N; Hosea, J C; Wilgen, J B; Harvey, R W; Smirnov, A P; Preinhaelter, J; Urban, J; Ram, A K

    2008-03-20

    A 28 GHz electron cyclotron heating (ECH) and electron Bernstein wave heating (EBWH) system has been proposed for installation on the National Spherical Torus Experiment (NSTX). A 350 kW gyrotron connected to a fixed horn antenna is proposed for ECH-assisted solenoid-free plasma startup. Modeling predicts strong first pass on-axis EC absorption, even for low electron temperature, Te ~ 20 eV, Coaxial Helicity Injection (CHI) startup plasmas. ECH will heat the CHI plasma to Te ~ 300 eV, providing a suitable target plasma for 30 MHz high-harmonic fast wave heating. A second gyrotron and steered O-X-B mirror launcher is proposed for EBWH experiments. Radiometric measurements of thermal EBW emission detected via B-X-O coupling on NSTX support implementation of the proposed system. 80% B-X-O coupling efficiency was measured in L-mode plasmas and 60% B-X-O coupling efficiency was recently measured in H-mode plasmas conditioned with evaporated lithium. Modeling predicts local on-axis EBW heating and current drive using 28 GHz power in β ~ 20% NSTX plasmas should be possible, with current drive efficiencies ~ 40 kA/MW.

  5. 110 GHz ECH on DIII-D: System overview and initial operation

    SciTech Connect

    Cary, W.P.; Allen, J.C.; Callis, R.W.; Doane, J.L.; Harris, T.E.; Moeller, C.P.; Nerem, A.; Prater, R.; Remsen, D.

    1991-11-01

    A new high power electron cyclotron heating (ECH) system has been introduced on D3-D. This system is designed to operate at 110 GHz with a total output power of 2 MW. The system consists of four Varian VGT-8011 gyrotrons, (output power of 500 kW), and their associated support equipment. All components have been designed for up to a 10 second pulse duration. The 110 GHz system is intended to further progress in rf current drive experiments on D3-D when used in conjunction with the existing 60 GHz ECH (1.6 MW), and the 30--60 MHz ICH (2 MW) systems. H-mode physics, plasma stabilization experiments and transport studies are also to be conducted at 110 GHz. The present system design philosophy was based on experience gained from the existing 60 GHz ECH system. The consequences of these design decisions will be addressed as will the actual performance of various 110 GHz components.

  6. Spacecraft multibeam antenna system for 30/20 GHz

    NASA Technical Reports Server (NTRS)

    Roberts, T. E.; Scott, W. F.

    1984-01-01

    The major technical tasks that led to the definitions of operational and demonstration multiple beam antenna (MBA) flight systems and a proof of concept model (POC) are described. Features of the POC Model and its measured performance are presented in detail. Similar MBA's are proposed for transmitting and receiving with the POC Model representing the 20 GHz transmitting antenna. This POC MBA is a dual shaped-surface reflector system utilizing a movable free array to simulate complete CONUS coverage. The beam forming network utilizes ferrite components for switching from one beam to another. Measured results for components, subsystems and the complete MBA confirm the feasibility of the approach and also show excellent correlation with calculated values.

  7. Control system renewal for efficient operation in RIKEN 18 GHz electron cyclotron resonance ion source

    SciTech Connect

    Uchiyama, A. Ozeki, K.; Higurashi, Y.; Kidera, M.; Komiyama, M.; Nakagawa, T.

    2016-02-15

    A RIKEN 18 GHz electron cyclotron resonance ion source (18 GHz ECRIS) is used as an external ion source at the Radioactive Ion Beam Factory (RIBF) accelerator complex to produce an intense beam of medium-mass heavy ions (e.g., Ca and Ar). In most components that comprise the RIBF, the control systems (CSs) are integrated by the Experimental Physics and Industrial Control System (EPICS). On the other hand, a non-EPICS-based system has hardwired controllers, and it is used in the 18 GHz ECRIS CS as an independent system. In terms of efficient and effective operation, the 18 GHz ECRIS CS as well as the RIBF CS should be renewed using EPICS. Therefore, we constructed an 18 GHz ECRIS CS by using programmable logic controllers with embedded EPICS technology. In the renewed system, an operational log system was developed as a new feature, for supporting of the 18 GHz ECRIS operation.

  8. Control system renewal for efficient operation in RIKEN 18 GHz electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Uchiyama, A.; Ozeki, K.; Higurashi, Y.; Kidera, M.; Komiyama, M.; Nakagawa, T.

    2016-02-01

    A RIKEN 18 GHz electron cyclotron resonance ion source (18 GHz ECRIS) is used as an external ion source at the Radioactive Ion Beam Factory (RIBF) accelerator complex to produce an intense beam of medium-mass heavy ions (e.g., Ca and Ar). In most components that comprise the RIBF, the control systems (CSs) are integrated by the Experimental Physics and Industrial Control System (EPICS). On the other hand, a non-EPICS-based system has hardwired controllers, and it is used in the 18 GHz ECRIS CS as an independent system. In terms of efficient and effective operation, the 18 GHz ECRIS CS as well as the RIBF CS should be renewed using EPICS. Therefore, we constructed an 18 GHz ECRIS CS by using programmable logic controllers with embedded EPICS technology. In the renewed system, an operational log system was developed as a new feature, for supporting of the 18 GHz ECRIS operation.

  9. A 90GHz Bolometer Camera Detector System for the Green

    NASA Technical Reports Server (NTRS)

    Benford, Dominic J.; Allen, Christine A.; Buchanan, Ernest; Chen, Tina C.; Chervenak, James A.; Devlin, Mark J.; Dicker, Simon R.; Forgione, Joshua B.

    2004-01-01

    We describe a close-packed, two-dimensional imaging detector system for operation at 90GHz (3.3 mm) for the 100m Green Bank Telescope (GBT). This system will provide high sensitivity (less than 1mJy in 1s) rapid imaging (15'x15' to 150 micron Jy in 1 hr) at the world's largest steerable aperture. The heart of this camera is an 8x8 close-packed, Nyquist-sampled array of superconducting transition edge sensor (TES) bolometers. We have designed and are producing a functional superconducting bolometer array system using a monolithic planar architecture and high-speed multiplexed readout electronics. With an NEP of approximately 2 x 10(exp -17) W/square root of Hz, the TES bolometers will provide fast, linear, sensitive response for high performance imaging. The detectors are read out by an 8x8 time domain SQUID multiplexer. A digital/analog electronics system has been designed to enable read out by SQUID multiplexers. First light for this instrument on the GBT is expected within a year.

  10. A 90GHz Bolometer Camera Detector System for the Green

    NASA Technical Reports Server (NTRS)

    Benford, Dominic J.; Allen, Christine A.; Buchanan, Ernest; Chen, Tina C.; Chervenak, James A.; Devlin, Mark J.; Dicker, Simon R.; Forgione, Joshua B.

    2004-01-01

    We describe a close-packed, two-dimensional imaging detector system for operation at 90GHz (3.3 mm) for the 100m Green Bank Telescope (GBT). This system will provide high sensitivity (less than 1mJy in 1s) rapid imaging (15'x15' to 150 micron Jy in 1 hr) at the world's largest steerable aperture. The heart of this camera is an 8x8 close-packed, Nyquist-sampled array of superconducting transition edge sensor (TES) bolometers. We have designed and are producing a functional superconducting bolometer array system using a monolithic planar architecture and high-speed multiplexed readout electronics. With an NEP of approximately 2 x 10(exp -17) W/square root of Hz, the TES bolometers will provide fast, linear, sensitive response for high performance imaging. The detectors are read out by an 8x8 time domain SQUID multiplexer. A digital/analog electronics system has been designed to enable read out by SQUID multiplexers. First light for this instrument on the GBT is expected within a year.

  11. The DIII-D 3 MW, 110 GHz ECH System

    SciTech Connect

    Callis, R.W.; Lohr, J.; Ponce, D.; O'Neill, R.C.; Prater, R.; Luce, T.C.

    1999-07-01

    Three 110 GHz gyrotrons with nominal output power of 1 MW each have been installed and are operational on the DIII-D tokamak. One gyrotron is built by Gycom and has a nominal rating of 1 MW and a 2 s pulse length, with the pulse length being determined by the maximum temperature allowed on the edge cooled Boron Nitride window. The second and third gyrotrons were built by Communications and Power Industries (CPI). The first CPI gyrotron uses a double disc FC-75 cooled sapphire window which has a pulse length rating of 0.8 s at 1 MW, 2s at 0.5 MW and 10s at 0.35 MW. The second CPI gyrotron, utilizes a single disc chemical-vapor-deposition diamond window, that employs water cooling around the edge of the disc. Calculation predict that the diamond window should be capable of full 1 MW cw operation. All gyrotrons are connected to the tokamak by a low-loss-windowless evacuated transmission line using circular corrugated waveguide for propagation in the HEl 1 mode. Each waveguide system incorporates a two mirror launcher which can steer the rf beam poloidally from the center to the outer edge of the plasma. Central current drive experiments with the two gyrotrons with 1.5 MW of injected power drove about 0.17 MA. Results from using the three gyrotron systems will be reported as well as the plans to upgrade the system to 6 MW.

  12. The 60 GHz antenna system analyses for intersatellite links, phase B

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The purpose of this study is first to investigate, classify, and compare applicable antenna systems capable of establishing and maintaining intersatellite links at 60 GHz and secondly to select the most applicable system for a detailed conceptual design. The results are to be applicable to the development of intersatellite links at 60 GHz for future programs. Design goals are listed.

  13. A deep/wide 1-2 GHz snapshot survey of SDSS Stripe 82 using the Karl G. Jansky Very Large Array in a compact hybrid configuration

    NASA Astrophysics Data System (ADS)

    Heywood, I.; Jarvis, M. J.; Baker, A. J.; Bannister, K. W.; Carvalho, C. S.; Hardcastle, M.; Hilton, M.; Moodley, K.; Smirnov, O. M.; Smith, D. J. B.; White, S. V.; Wollack, E. J.

    2016-08-01

    We have used the Karl G. Jansky Very Large Array to image ˜100 deg2 of SDSS Stripe 82 at 1-2 GHz. The survey consists of 1026 snapshot observations of 2.5 min duration, using the hybrid CnB configuration. The survey has good sensitivity to diffuse, low surface brightness structures and extended radio emission, making it highly synergistic with existing 1.4 GHz radio observations of the region. The principal data products are continuum images, with 16 × 10 arcsec resolution, and a catalogue containing 11 782 point and Gaussian components resulting from fits to the thresholded Stokes-I brightness distribution, forming approximately 8948 unique radio sources. The typical effective 1σ noise level is 88 μJy beam-1. Spectral index estimates are included, as derived from the 1 GHz of instantaneous bandwidth. Astrometric and photometric accuracy are in excellent agreement with existing narrowband observations. A large-scale simulation is used to investigate clean bias, which we extend into the spectral domain. Clean bias remains an issue for snapshot surveys with the VLA, affecting our total intensity measurements at the ˜1σ level. Statistical spectral index measurements are in good agreement with existing measurements derived from matching separate surveys at two frequencies. At flux densities below ˜35σ the median in-band spectral index measurements begin to exhibit a bias towards flatness that is dependent on both flux density and the intrinsic spectral index. In-band spectral curvature measurements are likely to be unreliable for all but the very brightest components. Image products and catalogues are publicly available via an FTP server.

  14. A 94/183 GHz aircraft radiometer system for Project Storm Fury

    NASA Technical Reports Server (NTRS)

    Gagliano, J. A.; Stratigos, J. A.; Forsythe, R. E.; Schuchardt, J. M.; Welch, J. M.; Gallentine, D. O.

    1980-01-01

    A radiometer design suitable for use in NASA's WB-57F aircraft to collect data from severe storm regions was developed. The design recommended was a 94/183 GHz scanning radiometer with 3 IF channels on either side of the 183.3 GHz water vapor line and a single IF channel for a low loss atmospheric window channel at 94 GHz. The development and construction of the 94/183 GHz scanning radiometer known as the Advanced Microwave Moisture Sounder (AMMS) is presented. The radiometer scans the scene below the aircraft over an angle of + or - 45 degrees with the beamwidth of the scene viewed of approximately 2 degrees at 94 GHz and 1 degree at 183 GHz. The AMMS data collection system consists of a microcomputer used to store the radiometer data on the flight cartridge recorder, operate the stepper motor driven scanner, and collect housekeeping data such as thermistor temperature readings and aircraft time code.

  15. A 94/183 GHz aircraft radiometer system for Project Storm Fury

    NASA Astrophysics Data System (ADS)

    Gagliano, J. A.; Stratigos, J. A.; Forsythe, R. E.; Schuchardt, J. M.; Welch, J. M.; Gallentine, D. O.

    1980-04-01

    A radiometer design suitable for use in NASA's WB-57F aircraft to collect data from severe storm regions was developed. The design recommended was a 94/183 GHz scanning radiometer with 3 IF channels on either side of the 183.3 GHz water vapor line and a single IF channel for a low loss atmospheric window channel at 94 GHz. The development and construction of the 94/183 GHz scanning radiometer known as the Advanced Microwave Moisture Sounder (AMMS) is presented. The radiometer scans the scene below the aircraft over an angle of + or - 45 degrees with the beamwidth of the scene viewed of approximately 2 degrees at 94 GHz and 1 degree at 183 GHz. The AMMS data collection system consists of a microcomputer used to store the radiometer data on the flight cartridge recorder, operate the stepper motor driven scanner, and collect housekeeping data such as thermistor temperature readings and aircraft time code.

  16. 146-GHz millimeter-wave radio-over-fiber photonic wireless transmission system.

    PubMed

    Fice, M J; Rouvalis, E; van Dijk, F; Accard, A; Lelarge, F; Renaud, C C; Carpintero, G; Seeds, A J

    2012-01-16

    We report the experimental implementation of a wireless transmission system with a 146-GHz carrier frequency which is generated by optical heterodyning the two modes from a monolithically integrated quantum dash dual-DFB source. The monolithic structure of the device and the inherent low noise characteristics of quantum dash gain material allow us to demonstrate the transmission of a 1 Gbps ON-OFF keyed data signal with the two wavelengths in a free-running state at 146-GHz carrier wave frequency. The tuning range of the device fully covers the W-band (75 - 110 GHz) and the F-band (90 - 140 GHz).

  17. The new 1.2 T{endash}14.5 GHz Caprice source of multicharged ions: Results with metallic elements

    SciTech Connect

    Hitz, D.; Bourg, F.; Delaunay, M.; Ludwig, P.; Melin, G.; Pontonnier, M.; NGuyen, T.K.

    1996-03-01

    The 1.2 T{endash}14.5 GHz ECR Caprice source is an upgrade version of previous Caprice sources where the three main ingredients of an ECR ion source of multicharged ions have been optimized: (i) the magnetic configuration has higher axial fields (1.4{endash}1.45 T at the mirror throats) and radial field (1.05 T at the wall inside the plasma chamber) as well as higher mirror ratios, (ii) the 14.5 GHz rf frequency is convenient to higher magnetic fields, and (iii) more efficient electron sources allow the electron density to reach higher values, and thus high extracted ion currents (both first stage and wall coating). Emphasis is given to the metallic elements, the source is able to produce 10 e{mu}A of Ca{sup 14+}, 3 e{mu}A of Fe{sup 17+} and Ni{sup 20+}, 1 e{mu}A of U{sup 37+}, while being able to deliver 1130 e{mu}A of O{sup 6+}, 190 e{mu}A of O{sup 7+}, and 100 e{mu}A of Ar{sup 12+}. {copyright} {ital 1996 American Institute of Physics.}

  18. Propagation effects on satellite systems at frequencies below 10 GHz: A handbook for satellite systems design

    NASA Technical Reports Server (NTRS)

    Flock, Warren L.

    1987-01-01

    Frequencies below 10 GHz continue to be used for a large portion of satellite service, and new applications, including mobile satellite service and the global positioning system, use frequencies below 10 GHz. As frequency decreases below 10 GHz, attenuation due to precipitation and gases decreases and ionospheric effects increase. Thus the ionosphere, which can be largely neglected above 10 GHz, receives major attention. Although attenuation and depolarization due to rain are less severe below 10 GHz than above, they are nevertheless still important and constitute another major topic. The handbook emphasizes the propagation effects on satellite communications but material that is pertinent to radio navigation and positioning systems and deep-space telecommunications is included as well. Chapter 1 through 7 describe the various propagation impairments, and Chapter 9 is devoted to the estimation or calculation of the magnitudes of these effects for use in system design. Chapter 10 covers link power budget equations and the role of propagation effects in these equations. Chapter 8 deals with the complex subject of interference between space and terrestrial systems.

  19. 47 CFR 15.252 - Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz. 15.252 Section 15.252 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission...

  20. 47 CFR 15.252 - Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz. 15.252 Section 15.252 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission...

  1. 47 CFR 15.252 - Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz. 15.252 Section 15.252 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission...

  2. 47 CFR 15.252 - Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz. 15.252 Section 15.252 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission...

  3. 47 CFR 15.252 - Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Operation of wideband vehicular radar systems within the bands 16.2-17.7 GHz and 23.12-29.0 GHz. 15.252 Section 15.252 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission...

  4. Market capture by 30/20 GHz satellite systems. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Gamble, R. B.; Saporta, L.

    1981-01-01

    Demand for 30/20 GHz satellite systems over the next two decades is projected. Topics include a profile of the communications market, switched, dedicated, and packet transmission modes, deferred and real-time traffic, quality and reliability considerations, the capacity of competing transmission media, and scenarios for the growth and development of 30/20 GHz satellite communications.

  5. A Compact 600 GHz Electronically Tunable Vector Measurement System for Submillimeter Wave Imaging

    NASA Technical Reports Server (NTRS)

    Dengler, Robert; Maiwald, Frank; Siegel, Peter H.

    2006-01-01

    The design of a complete vector measurement system being tested over 560-635 GHz is presented. The topics include: 1) Current State-of-the-Art in Vector Measurements; 2) Submillimeter Active Imaging Requirements; 3) 600 GHz Vector Measurement System; 4) 450 MHz IF Signal; 5) 450 MHz IF signal @ 1 kHz Res. BW; 6) 450 MHz IF Signal Mixed with Shifted 450 MHz Reference Signal; 7) Reference Signal Offset Generator; 8) Cavity Bandpass Filter; 9) Miniature Multistage Helical Filter; 10) X36 450 MHz Multiplier; 11) 600 GHz Test Setup; 12) 600 GHz Transmit Module; 13) 600 GHz Receive Module; 14) Performance Tests: Amplitude Stability & Dynamic Range; 15) Performance Tests: Phase Stability; 16) Stability at Imaging Bandwidths; 17) Phase Measurement Verification; and 18) The Next Step: Imaging.

  6. Electromagnetic radiation from ingested sources in the human intestine between 150 MHz and 1.2 GHz.

    PubMed

    Chirwa, Lawrence C; Hammond, Paul A; Roy, Scott; Cumming, David R S

    2003-04-01

    The conventional method of diagnosing disorders of the human gastro-intestinal (GI) tract is by sensors embedded in cannulae that are inserted through the anus, mouth, or nose. However, these cannulae cause significant patient discomfort and cannot be used in the small intestine. As a result, there is considerable ongoing work in developing wireless sensors that can be used in the small intestine. The radiation characteristics of sources in the GI tract cannot be readily calculated due to the complexity of the human body and its composite tissues, each with different electrical characteristics. In addition, the compact antennas used are electrically small, making them inefficient radiators. This paper presents radiation characteristics for sources in the GI tract that should allow for the optimum design of more efficient telemetry systems. The characteristics are determined using the finite-difference time-domain method with a realistic antenna model on an established fully segmented human body model. Radiation intensity outside the body was found to have a Gaussian-form relationship with frequency. Maximum radiation occurs between 450 and 900 MHz. The gut region was found generally to inhibit vertically polarized electric fields more than horizontally polarized fields.

  7. The effects of rain on system performance for the NASA 30/20 GHz Experimental Satellite

    NASA Technical Reports Server (NTRS)

    Ippolito, L. J.

    1982-01-01

    A 30/20 GHz Experimental Communications Satellite System is presently under study by NASA to evaluate system technology and high data rate multi-beam communications techniques. In this paper the expected system performance for the 30/20 GHz Satellite is presented, for both trunking and customer premise service (CPS) modes, with particular emphasis on the effects of severe rain events on link reliability. A rain attenuation prediction model technique is described and path and two-way link availabilities are developed for the various modes of operation. The results indicate that acceptable link availabilities can be expected on the 30/20 GHz system for both the trunking and CPS modes, and the experimental satellite system can form the basis for verification of system performance for operational 30/20 GHz systems.

  8. Microwave ablation using 915-MHz and 2.45-GHz systems: what are the differences?

    PubMed Central

    Simo, Kerri A; Tsirline, Victor B; Sindram, David; McMillan, Matthew T; Thompson, Kyle J; Swan, Ryan Z; McKillop, Iain H; Martinie, John B; Iannitti, David A

    2013-01-01

    Objectives This study was conducted to evaluate differences between 915-MHz and 2.45-GHz microwave ablation (MWA) systems in the ablation of hepatic tumours. Methods A retrospective analysis of patients undergoing hepatic tumour MWA utilizing two different systems over a 10-month period was carried out. Results Data for a total of 48 patients with a mean age of 58 ± 1.24 years were analysed. A total of 124 tumours were ablated; 72 tumours were ablated with a 915-MHz system and 52 with a 2.45-GHz system. Mean tumour diameters were 1.7 ± 0.1 cm in the 915-MHz group and 2.5 ± 0.2 cm in the 2.45-GHz group (P < 0.01). Mean ablation time per burn was 8.1 ± 0.3 min in the 915-MHz group and 4.0 ± 0.1 min in the 2.45-GHz group (P < 0.01). The mean number of burns per lesion was 2.0 ± 0.1 in the 915-MHz group and 1.7 ± 0.1 in the 2.45-GHz group (P < 0.05). The mean ablation time per lesion was 9.7 ± 0.7 min in the 915-MHz group, and 6.6 ± 0.6 min in the 2.45-GHz group (P < 0.01). The 2.45-GHz system demonstrated a better correlation between ablation time and tumour size (r2 = 0.6222) than the 915-MHz system; (r2 = 0.0696). Mean total energy applied per lesion, and energy applied per cm, were greater with the 915-MHz system (P < 0.05 and P < 0.01, respectively). Total energy applied per lesion was similarly correlated for the 2.45-GHz (r2 = 0.6263) and 915-MHz (r2 = 0.7012) systems. Mean total energy applied per cm/min was greater with the 2.45-GHz system (P < 0.05). Conclusions Both 915-MHz and 2.45-GHz MWA systems achieve reproducible hepatic tumour ablation. The 2.45-GHz system achieves equivalent, but more predictable and faster ablations using a single antenna system. PMID:23490330

  9. The 30/20 GHz fixed communications systems service demand assessment. Volume 3: Appendices

    NASA Technical Reports Server (NTRS)

    Gabriszeski, T.; Reiner, P.; Rogers, J.; Terbo, W.

    1979-01-01

    The market analysis of voice, video, and data 18/30 GHz communications systems services and satellite transmission services is discussed. Detail calculations, computer displays of traffic, survey questionnaires, and detailed service forecasts are presented.

  10. Concepts for 18/30 GHz satellite communication system, volume 1

    NASA Technical Reports Server (NTRS)

    Jorasch, R.; Baker, M.; Davies, R.; Cuccia, L.; Mitchell, C.

    1979-01-01

    Concepts for 18/30 GHz satellite communication systems are presented. Major terminal trunking as well as direct-to-user configurations were evaluated. Critical technologies in support of millimeter wave satellite communications were determined.

  11. The 30/20 GHz flight experiment system, phase 2. Volume 2: Experiment system description

    NASA Technical Reports Server (NTRS)

    Bronstein, L.; Kawamoto, Y.; Ribarich, J. J.; Scope, J. R.; Forman, B. J.; Bergman, S. G.; Reisenfeld, S.

    1981-01-01

    A detailed technical description of the 30/20 GHz flight experiment system is presented. The overall communication system is described with performance analyses, communication operations, and experiment plans. Hardware descriptions of the payload are given with the tradeoff studies that led to the final design. The spacecraft bus which carries the payload is discussed and its interface with the launch vehicle system is described. Finally, the hardwares and the operations of the terrestrial segment are presented.

  12. The 18/30 GHz fixed communications system service demand assessment. Volume 2: Main text

    NASA Technical Reports Server (NTRS)

    Gabriszeski, T.; Reiner, P.; Rogers, J.; Terbo, W.

    1979-01-01

    The total demand for communications services, and satellite transmission services at the 4/6 GHz, 12/14 GHz, and 18/30 GHz frequencies is assessed. The services are voice, video, and data services. Traffic demand, by service, is distributed by geographical regions, population density, and distance between serving points. Further distribution of traffic is made among four major end user groups: business, government, institutions and private individuals. A traffic demand analysis is performed on a typical metropolitan city to examine service distribution trends. The projected cost of C and Ku band satellite systems are compared on an individual service basis to projected terrestrial rates. Separation of traffic between transmission systems, including 18/30 GHz systems, is based on cost, user, and technical considerations.

  13. Inter-spin distance determination using L-band (1-2 GHz) non-adiabatic rapid sweep electron paramagnetic resonance (NARS EPR)

    NASA Astrophysics Data System (ADS)

    Kittell, Aaron W.; Hustedt, Eric J.; Hyde, James S.

    2012-08-01

    Site-directed spin-labeling electron paramagnetic resonance (SDSL EPR) provides insight into the local structure and motion of a spin probe strategically attached to a molecule. When a second spin is introduced to the system, macromolecular information can be obtained through measurement of inter-spin distances either by continuous wave (CW) or pulsed electron double resonance (ELDOR) techniques. If both methodologies are considered, inter-spin distances of 8-80 Å can be experimentally determined. However, there exists a region at the upper limit of the conventional X-band (9.5 GHz) CW technique and the lower limit of the four-pulse double electron-electron resonance (DEER) experiment where neither method is particularly reliable. The work presented here utilizes L-band (1.9 GHz) in combination with non-adiabatic rapid sweep (NARS) EPR to address this opportunity by increasing the upper limit of the CW technique. Because L-band linewidths are three to seven times narrower than those at X-band, dipolar broadenings that are small relative to the X-band inhomogeneous linewidth become observable, but the signal loss, due to the frequency dependence of the Boltzmann factor, has made L-band especially challenging. NARS has been shown to increase sensitivity by a factor of five, and overcomes much of this loss, making L-band distance determination more feasible [1]. Two different systems are presented, and distances of 18-30 Å have been experimentally determined at physiologically relevant temperatures. Measurements are in excellent agreement with a helical model and values determined by DEER.

  14. Inter-spin distance determination using L-band (1-2 GHz) non-adiabatic rapid sweep electron paramagnetic resonance (NARS EPR)

    PubMed Central

    Kittell, Aaron W.; Hustedt, Eric J.; Hyde, James S.

    2014-01-01

    Site-directed spin-labeling electron paramagnetic resonance (SDSL EPR) provides insight into the local structure and motion of a spin probe strategically attached to a molecule. When a second spin is introduced to the system, macromolecular information can be obtained through measurement of inter-spin distances either by continuous wave (CW) or pulsed electron double resonance (ELDOR) techniques. If both methodologies are considered, inter-spin distances of 8 to 80 Å can be experimentally determined. However, there exists a region at the upper limit of the conventional X-band (9.5 GHz) CW technique and the lower limit of the four-pulse double electron-electron resonance (DEER) experiment where neither method is particularly reliable. The work presented here utilizes L-band (1.9 GHz) in combination with non-adiabatic rapid sweep (NARS) EPR to address this opportunity by increasing the upper limit of the CW technique. Because L-band linewidths are three to seven times narrower than those at X-band, dipolar broadenings that are small relative to the X-band inhomogeneous linewidth become observable, but the signal loss due to the frequency dependence of the Boltzmann factor, has made L-band especially challenging. NARS has been shown to increase sensitivity by a factor of five, and overcomes much of this loss, making L-band distance determination more feasible [1]. Two different systems are presented and distances of 18–30 Å have been experimentally determined at physiologically relevant temperatures. Measurements are in excellent agreement with a helical model and values determined by DEER. PMID:22750251

  15. High-Frequency Wireless Communications System: 2.45-GHz Front-End Circuit and System Integration

    ERIC Educational Resources Information Center

    Chen, M.-H.; Huang, M.-C.; Ting, Y.-C.; Chen, H.-H.; Li, T.-L.

    2010-01-01

    In this article, a course on high-frequency wireless communications systems is presented. With the 145-MHz baseband subsystem available from a prerequisite course, the present course emphasizes the design and implementation of the 2.45-GHz front-end subsystem as well as system integration issues. In this curriculum, the 2.45-GHz front-end…

  16. High-Frequency Wireless Communications System: 2.45-GHz Front-End Circuit and System Integration

    ERIC Educational Resources Information Center

    Chen, M.-H.; Huang, M.-C.; Ting, Y.-C.; Chen, H.-H.; Li, T.-L.

    2010-01-01

    In this article, a course on high-frequency wireless communications systems is presented. With the 145-MHz baseband subsystem available from a prerequisite course, the present course emphasizes the design and implementation of the 2.45-GHz front-end subsystem as well as system integration issues. In this curriculum, the 2.45-GHz front-end…

  17. Active wideband 350GHz imaging system for concealed-weapon detection

    NASA Astrophysics Data System (ADS)

    Sheen, David M.; Hall, Thomas E.; Severtsen, Ronald H.; McMakin, Douglas L.; Hatchell, Brian K.; Valdez, Patrick L. J.

    2009-05-01

    A prototype active wideband 350 GHz imaging system has been developed to address the urgent need for standoff concealed-weapon detection. This system is based on a wideband, heterodyne, frequency-multiplier-based transceiver system coupled to a quasi-optical focusing system and high-speed conical scanner. This system is able to quickly scan personnel for concealed weapons. Additionally, due to the wideband operation, this system provides accurate ranging information, and the images obtained are fully three-dimensional. Waves in the microwave, millimeter-wave, and terahertz (3 GHz to 1 THz) frequency bands are able to penetrate many optical obscurants, and can be used to form the basis of high-resolution imaging systems. Waves in the sub-millimeter-wave band (300 GHz to 1 THz) are particularly interesting for standoff concealed-weapon detection at ranges of 5 - 20+ meters, due to their unique combination of high resolution and clothing penetration. The Pacific Northwest National Laboratory (PNNL) has previously developed portal screening systems that operate at the lower end of the millimeter-wave frequency range around 30 GHz. These systems are well suited for screening within portals; however, increasing the range of these systems would dramatically reduce the resolution due to diffraction at their relatively long wavelength. In this paper, the standoff 350 GHz imaging system is described in detail and numerous imaging results are presented.

  18. Design of a 300 GHz Band TWT with a Folded Waveguide Fabricated by Microelectromechanical Systems

    NASA Astrophysics Data System (ADS)

    Tsutaki, Kunio; Neo, Yoichiro; Mimura, Hidenori; Masuda, Norio; Yoshida, Mitsuru

    2016-12-01

    For future broadband wireless links, we have designed a 300 GHz band traveling wave tube (TWT) with a folded waveguide fabricated by microelectromechanical systems (MEMS). The TWT operates at a beam voltage of 12 kV and a beam current of 8.3 mA. The classical large signal simulation code predicts the output power greater than 1 W and gain larger than 20 dB over the bandwidth from 280 to 300 GHz.

  19. The 30/20 GHz flight experiment system, phase 2. Volume 4: Experiment system development plan

    NASA Technical Reports Server (NTRS)

    Bronstein, L.; Kawamoto, Y.; Riberich, J. J.; Scope, J. R.; Forman, B. J.; Bergman, S. G.; Reisenfeld, S.

    1981-01-01

    The development plan for the 30/20 GHz flight experiment system is presented. A master program schedule with detailed development plans for each subsystem is planned with careful attention given to how technology items to ensure a minimal risk. The work breakdown structure shows the organization of the program management with detailed task definitions. The ROM costs based on the development plan are also given.

  20. 20/30 GHz satellite systems technology needs assessment. [for domestic communications

    NASA Technical Reports Server (NTRS)

    Stevens, G.; Wright, D.

    1978-01-01

    The paper surveys the system and market work done at NASA-Lewis with regard to exploring the potential of the 20/30 GHz bands for domestic satellite communications. The 20/30 GHz bands appear attractive economically and, with certain technology advances, appear to offer a virtually unlimited spectrum resource. This attractiveness is especially relevant to high density trunking where there is sufficient traffic to justify dual-station site diversity. Ongoing system and market studies actively involve satellite system suppliers and carriers as well as the government in a cooperative, mutually beneficial effort. It is considered that this is the approach most likely to result in a spectrum-efficient acceptable-risk high-capacity 30/30 GHz satellite system which is relevant to anticipated markets.

  1. A novel ultra-wideband 80 GHz FMCW radar system for contactless monitoring of vital signs.

    PubMed

    Wang, Siying; Pohl, Antje; Jaeschke, Timo; Czaplik, Michael; Köny, Marcus; Leonhardt, Steffen; Pohl, Nils

    2015-01-01

    In this paper an ultra-wideband 80 GHz FMCW-radar system for contactless monitoring of respiration and heart rate is investigated and compared to a standard monitoring system with ECG and CO(2) measurements as reference. The novel FMCW-radar enables the detection of the physiological displacement of the skin surface with submillimeter accuracy. This high accuracy is achieved with a large bandwidth of 10 GHz and the combination of intermediate frequency and phase evaluation. This concept is validated with a radar system simulation and experimental measurements are performed with different radar sensor positions and orientations.

  2. 2 × 2 MIMO radio-over-fiber system at 60 GHz employing frequency domain equalization.

    PubMed

    Lin, Chun-Ting; Ng'oma, Anthony; Lee, Wei-Yuan; Wei, Chia-Chien; Wang, Chih-Yun; Lu, Tsung-Hung; Chen, Jyehong; Jiang, Wen-Jr; Ho, Chun-Hung

    2012-01-02

    This work experimentally demonstrates the efficacy of the 2 × 2 multiple-input multiple-output (MIMO) technique for capacity improvement of a 60-GHz radio-over-fiber (RoF) system employing single-carrier modulation format. We employ frequency domain equalization (FDE) to estimate the channel response, including frequency response of the 60 GHz RoF system and the MIMO wireless channel. Using FDE and MIMO techniques, we experimentally demonstrate the doubling the of wireless data capacity of a 60 GHz RoF system to 27.15 Gb/s using 16-QAM modulation format, with transmission over 25 km of standard single-mode fiber and 3 m wireless distance.

  3. Generating multi-mode entangled coherent W and GHZ states via optical system based fusion mechanism

    NASA Astrophysics Data System (ADS)

    Zang, Xue-Ping; Yang, Ming; Wu, Wei-Feng; Fan, Hong-Yi

    2017-05-01

    Fusion technology has been demonstrated to be a good method for generating a large-scale entangled coherent W or GHZ state from two small ones in QED system. It is of importance to study how to fuse small-scale entangled coherent W or GHZ states via optical system. In this paper, we present a scheme for generating larger entangled coherent W or GHZ state in an optical system by virtue of fusion technology. The key fusion mechanism is realized by photon detectors and a Mach-Zehnder interferometer with its two arms immersed in Kerr media, by which an n-mode entangled coherent W state and an m-mode entangled coherent W state can be probabilistically fused into an (n+m-2)-mode entangled coherent W state. This fusion scheme applies to entangled coherent GHZ state too but with a unit probability of success. Feasibility analysis indicates that our fusion scheme may be realized with current experimental technology. Large-scale entangled coherent W and GHZ states may find new applications in quantum communication.

  4. Lyapunov-Based Feedback Preparation of GHZ Entanglement of N-Qubit Systems.

    PubMed

    Liu, Yanan; Kuang, Sen; Cong, Shuang

    2016-07-09

    The Greenberger-Horne-Zeilinger (GHZ) entangled states are a typical class of entangled states in multiparticle systems and play an important role in the applications of quantum communication and quantum computation. For a general quantum system of N qubits, degenerate measurement operators are often met, which cause the convergence obstacle in the state preparation or stabilization problem. This paper first generalizes the traditional quantum state continuous reduction theory to the case of a degenerate measurement operator and chooses a measurement operator for an arbitrarily given target GHZ entangled state, then presents a state stabilization control strategy based on the Lyapunov method and achieves the feedback preparation of the target GHZ state. In our stabilization strategy, we separate the target GHZ state and all the other GHZ states that often form the equilibrium points of the closed-loop system by dividing the state space into several different regions; and formally design a switching control law between the regions, which contains the control Hamiltonians to be constructed. By analyzing the stability of the closed-loop system in the different regions, we propose a systematic method for constructing the control Hamiltonians and solve the convergence problem caused by the degenerate measurement operator. The global stability of the whole closed-loop stochastic system is strictly proved. Also, we perform some simulation experiments on a three-qubit system and prepare a three-qubit GHZ entangled state. At the same time, the simulation results show the effectiveness of the switching control law and the construction method for the control Hamiltonians proposed in this paper.

  5. Magnetic dimers and trimers in the disordered S =3/2 spin system BaTi1/2Mn1/2O3

    NASA Astrophysics Data System (ADS)

    Garcia, F. A.; Kaneko, U. F.; Granado, E.; Sichelschmidt, J.; Hölzel, M.; Duque, J. G. S.; Nunes, C. A. J.; Amaral, R. P.; Marques-Ferreira, P.; Lora-Serrano, R.

    2015-06-01

    We report a structural-magnetic investigation by x-ray absorption spectroscopy (XAS), neutron diffraction, dc susceptibility (χdc), and electron spin resonance (ESR) of the 12R-type perovskite BaTi1/2Mn1/2O3 . Our structural analysis by neutron diffraction supports the existence of structural trimers with chemically disordered occupancy of Mn4+ and Ti4+ ions, with the valence of the Mn ions confirmed by the XAS measurements. The magnetic properties are explored by combining dc-susceptibility and X -band (9.4 GHz) electron spin resonance, both in the temperature interval of 2 ≤T ≤1000 K. A scenario is presented under which the magnetism is explained by considering magnetic dimers and trimers, with exchange constants Ja/kB=200 (2 ) K and Jb/kB=130 (10 ) K, and orphan spins. Thus, BaTi1/2Mn1/2O3 is proposed as a rare case of an intrinsically disordered S =3/2 spin gap system with a frustrated ground state.

  6. The 30/20 GHz fixed communications systems service demand assessment. Volume 3: Annex

    NASA Technical Reports Server (NTRS)

    Gamble, R. B.; Seltzer, H. R.; Speter, K. M.; Westheimer, M.

    1979-01-01

    A review of studies forecasting the communication market in the United States is given. The applicability of these forecasts to assessment of demand for the 30/20 GHz fixed communications system is analyzed. Costs for the 30/20 satellite trunking systems are presented and compared with the cost of terrestrial communications.

  7. Market capture by 30/20 GHz satellite systems, volume 2

    NASA Technical Reports Server (NTRS)

    Gamble, R. B.; Saporta, L.

    1981-01-01

    Results of a telecommunications demand study are presented. Forecasts of demand for 30/20 GHz satellite systems, and the expected build up of traffic on these systems are given as a function of time for each of several operational scenarios.

  8. Status of KSTAR 170 GHz, 1 MW Electron Cyclotron Heating and Current Drive System

    SciTech Connect

    Joung, M.; Bae, Y. S.; Jeong, J. H.; Park, S.; Kim, H. J.; Yang, H. L.; Park, H.; Cho, M. H.; Namkung, W.; Hosea, J.; Ellis, R.; Sakamoto, K.; Kajiwara, K.; Doane, J.

    2011-12-23

    A 170 GHz Electron Cyclotron Heating and Current Drive (ECH/CD) system on KSTAR is designed to launch total 2.4 MW of power for up to 300 sec into the plasma. At present the first 1 MW ECH/CD system is under installation and commissioning for 2011 KSTAR campaign. The 170 GHz, 1 MW, 300 sec gyrotron and the matching optics unit (MOU) will be provided from JAEA under collaboration between NFRI and JAEA. The transmission line consists of MOU and 70 m long 63.5 mm ID corrugated waveguides with the eight miter bends. The 1 MW, 10 sec launcher is developed based on the existing two-mirror front-end launcher in collaboration with Princeton Plasma Physics Laboratory and Pohang University of Science and Technology, and is installed on the low field side in the KSTAR equatorial plane. The mirror pivot is located at 30 cm below from the equatorial plane. 3.6 MVA power supply system is manufactured and now is under commissioning to meet the triode gun operation of JAEA gyrotron. The power supply consists of 66 kV/55 A cathode power supply, mode-anode system, and 50 kV/160 mA body power supply. In this paper, the current status of KSTAR 170 GHz, 1 MW ECH/CD system will be presented as well as the experimental plan utilizing 170 GHz new ECH/CD system.

  9. Wireless Channel Characterization in the 5 GHz Microwave Landing System Extension Band for Airport Surface Areas

    NASA Technical Reports Server (NTRS)

    Matolak, David W.

    2007-01-01

    In this project final report, entitled "Wireless Channel Characterization in the 5 GHz Microwave Landing System Extension Band for Airport Surface Areas," we provide a detailed description and model representation for the wireless channel in the airport surface environment in this band. In this executive summary, we review report contents, describe the achieved objectives and major findings, and highlight significant conclusions and recommendations.

  10. Design studies of the output system of a 95 GHz, 100 kW, CW gyrotron

    SciTech Connect

    Vamshi Krishna, P.; Kartikeyan, M.V. E-mail: kartik@iitr.ernet.in; Thumm, M.

    2011-07-01

    This paper presents the design studies of the output system of a 95 GHz, 100 kW, CW gyrotron for ECRH7ECRIS applications. During this course, the design studies of an advanced dimpled-wall quasi optical launcher, non-linear taper and RF window will be carried out. (author)

  11. An FDMA system concept for 30/20 GHz high capacity domestic satellite service

    NASA Technical Reports Server (NTRS)

    Berk, G.; Jean, P. N.; Rotholz, E.; White, B. E.

    1982-01-01

    The paper summarizes a feasibility study of a multibeam FDMA satellite system operating in the 30/20 GHz band. The system must accommodate a very high volume of traffic within the restrictions of a 5 kW solar cell array and a 2.5 GHz bandwidth. Multibeam satellite operation reduces the DC power demand and allows reuse of the available bandwidth. Interferences among the beams are brought to acceptable levels by appropriate frequency assignments. A transponder design is presented; it is greatly simplified by the application of a regional concept. System analysis shows that MSK modulation is appropriate for a high-capacity system because it conserves the frequency spectrum. Rain attenuation, a serious problem in this frequency band, is combatted with sufficient power margins and with coding. Link budgets, cost analysis, and weight and power calculations are also discussed. A satellite-routed FDMA system compares favorably in performance and cost with a satellite-switched TDMA system.

  12. Physics Design of a 28 GHz Electron Heating System for the National Spherical Torus Experiment Upgrade

    SciTech Connect

    2013-07-09

    A megawatt-level, 28 GHz electron heating system is being designed to support non-inductive (NI) plasma current (I{sub p}) start-up and local heating and current drive (CD) in H-mode discharges in the National Spherical Torus Experiment Upgrade (NSTX-U). The development of fully NI I{sub p} start-up and ramp-up is an important goal of the NSTX-U research program. 28 GHz electron cyclotron (EC) heating is predicted to rapidly increase the central electron temperature (T{sub e}(0)) of low density NI plasmas generated by Coaxial Helicity Injection (CHI). The increased T{sub e}(0) will significantly reduce the Ip decay rate of CHI plasmas, allowing the coupling of fast wave heating and neutral beam injection. Also 28 GHz electron Bernstein wave (EBW) heating and CD can be used during the I{sub p} flat top in NSTX-U discharges when the plasma is overdense. Ray tracing and Fokker-Planck numerical simulation codes have been used to model EC and EBW heating and CD in NSTX-U. This paper presents a pre-conceptual design for the 28 GHz heating system and some of the results from the numerical simulations.

  13. Customer premise service study for 30/20 GHz satellite system

    NASA Technical Reports Server (NTRS)

    Milton, R. T.; Ross, D. P.; Harcar, A. R.; Freedenberg, P.; Schoen, D.

    1983-01-01

    Satellite systems in which the space segment operates in the 30/20 GHz frequency band are defined and compared as to their potential for providing various types of communications services to customer premises and the economic and technical feasibility of doing so. Technical tasks performed include: market postulation, definition of the ground segment, definition of the space segment, definition of the integrated satellite system, service costs for satellite systems, sensitivity analysis, and critical technology. Based on an analysis of market data, a sufficiently large market for services is projected so as to make the system economically viable. A large market, and hence a high capacity satellite system, is found to be necessary to minimize service costs, i.e., economy of scale is found to hold. The wide bandwidth expected to be available in the 30/20 GHz band, along with frequency reuse which further increases the effective system bandwidth, makes possible the high capacity system. Extensive ground networking is required in most systems to both connect users into the system and to interconnect Earth stations to provide spatial diversity. Earth station spatial diversity is found to be a cost effective means of compensating the large fading encountered in the 30/20 GHz operating band.

  14. Concepts for 18/30 GHz satellite communication system study. Executive summary

    NASA Technical Reports Server (NTRS)

    Baker, M.; Davies, R.; Cuccia, L.; Mitchell, C.

    1979-01-01

    An examination of a multiplicity of interconnected parameters ranging from specific technology details to total system economic costs for satellite communication systems at the 18/30 GHz transmission bands are presented. It was determined that K sub A band systems can incur a small communications outage during very heavy rainfall periods and that reducing the outage to zero would lead to prohibitive system costs. On the other hand, the economics of scale, ie, one spacecraft accommodating 2.5 GHz of bandwidth coupled with multiple beam frequency reuse, leads to very low costs for those users who can tolerate the 5 to 50 hours per year of downtime. A multiple frequency band satellite network can provide the ultimate optimized match to the consumer performance/economics demands.

  15. Standoff concealed weapon detection using a 350 GHz radar imaging system

    SciTech Connect

    Sheen, David M.; Hall, Thomas E.; Severtsen, Ronald H.; McMakin, Douglas L.; Hatchell, Brian K.; Valdez, Patrick LJ

    2010-04-01

    The Pacific Northwest National Laboratory is currently developing a 350 GHz, active, wideband, three-dimensional, radar imaging system to evaluate the feasibility of active sub-mm imaging for standoff concealed weapon detection. The prototype radar imaging system is based on a wideband, heterodyne, frequency-multiplier-based transceiver system coupled to a quasi-optical focusing system and high-speed rotating conical scanner. The wideband operation of this system provides accurate ranging information, and the images obtained are fully three-dimensional. Recent improvements to the system include increased imaging speed using improved balancing techniques, wider bandwidth, and image display techniques.

  16. Optical-fiber-connected 300-GHz FM-CW radar system

    NASA Astrophysics Data System (ADS)

    Kanno, Atsushi; Sekine, Norihiko; Kasamatsu, Akifumi; Yamamoto, Naokatsu; Kawanishi, Tetsuya

    2017-05-01

    300-GHz frequency-modulated continuous-wave (FM-CW) radar system operated by radio over fiber technologies is configured and demonstrated. Centralized signal generator, which is based on an optical frequency comb generation, provides high-precise FM-CW radar signal. The optical signal is easy to be transported to radar heads through an optical fiber network. Optical-modulator-based optical frequency comb generator is utilized as an optical frequency multiplier from a microwave signal to a 300-GHz terahertz signal by an optical modulation technique. In the study, we discuss the configuration of the network, signal generator and remote radar head for terahertz-wave multi-static radar system.

  17. A Novel 24 Ghz One-Shot Rapid and Portable Microwave Imaging System (Camera)

    NASA Technical Reports Server (NTRS)

    Ghasr, M.T.; Abou-Khousa, M.A.; Kharkovsky, S.; Zoughi, R.; Pommerenke, D.

    2008-01-01

    A novel 2D microwave imaging system at 24 GHz based on MST techniques. Enhanced sensitivity and SNR by utilizing PIN diode-loaded resonant slots. Specific slot and array design to increase transmission and reduce cross -coupling. Real-time imaging at a rate in excess of 30 images per second. Reflection as well transmission mode capabilities. Utility and application for electric field distribution mapping related to: Nondestructive Testing (NDT), imaging applications (SAR, Holography), and antenna pattern measurements.

  18. An automated 60 GHz open resonator system for precision dielectric measurement

    NASA Astrophysics Data System (ADS)

    Afsar, Mohammed N.; Li, Xiaohui; Chi, Hua

    1990-12-01

    An automated open resonator system was designed and constructed for precision measurement of the loss tangent and dielectric permittivity of low absorbing materials at 60 GHz. The use of a high-Q hemispherical Fabry-Perot cavity together with highly stabilized synthesized phase-locked Gunn oscillator sources and a superheterodyne receiver made it possible to measure loss tangent values as low as 10 microrad. Both cavity length variation and frequency variation techniques were utilized to provide precise data.

  19. Gas spectroscopy system with 245 GHz transmitter and receiver in SiGe BiCMOS

    NASA Astrophysics Data System (ADS)

    Schmalz, Klaus; Rothbart, Nick; Borngräber, Johannes; Yilmaz, Selahattin Berk; Kissinger, Dietmar; Hübers, Heinz-Wilhelm

    2017-02-01

    The implementation of an integrated mm-wave transmitter (TX) and receiver (RX) in SiGe BiCMOS or CMOS technology offers a path towards a compact and low-cost system for gas spectroscopy. Previously, we have demonstrated TXs and RXs for spectroscopy at 238 -252 GHz and 495 - 497 GHz using external phase-locked loops (PLLs) with signal generators for the reference frequency ramps. Here, we present a more compact system by using two external fractional-N PLLs allowing frequency ramps for the TX and RX, and for TX with superimposed frequency shift keying (FSK) or reference frequency modulation realized by a direct digital synthesizer (DDS) or an arbitrary waveform generator. The 1.9 m folded gas absorption cell, the vacuum pumps, as well as the TX and RX are placed on a portable breadboard with dimensions of 75 cm x 45 cm. The system performance is evaluated by high-resolution absorption spectra of gaseous methanol at 13 Pa for 241 - 242 GHz. The 2f (second harmonic) content of the absorption spectrum of the methanol was obtained by detecting the IF power of RX using a diode power sensor connected to a lock-in amplifier. The reference frequency modulation reveals a higher SNR (signal-noise-ratio) of 98 within 32 s acquisition compared to 66 for FSK. The setup allows for jumping to preselected frequency regions according to the spectral signature thus reducing the acquisition time by up to one order of magnitude.

  20. Feasibility of an EHF (40/50 GHz) mobile satellite system using highly inclined orbits

    NASA Technical Reports Server (NTRS)

    Falciasecca, G.; Paraboni, A.; Ruggieri, M.; Valdoni, F.; Vatalaro, F.

    1990-01-01

    The pan-European L-band terrestrial cellular system (GSM) is expected to provide service to more than 10 million users by the year 2000. Discussed here is the feasibility of a new satellite system at EHF (40/50 GHz) to complement, at the end of the decade, the GSM system or its decendants in order to provide additional services at 64 kbits/s, or so. The main system aspects, channel characteristics, technology issues, and both on-board and earth terminal architectures are highlighted. Based on the performed analyses, a proposal was addressed to the Italian Space Agency (ASI), aimed at the implementation of a national plan.

  1. The 30/20 GHz demonstration system SSUS-D/BSE

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The systems consisting of a 30/20 GHz communication satellite featuring a multiple fixed beam and scanning beam antenna, SS-TDMA, onboard processing and high power TWT's and IMPATT amplifiers, a trunking space-diversity Earth station, a customer premise system (CPS) portable Earth station and a Master Control Station. Hardware, software and personnel are included to build and launch one satellite and to carry on a two year experimentation and demonstration period of advanced Ka-band systems concepts and technology. Included are first level plans identifying all tasks, a schedule for system development and an assessment of critical technology and risk and a preliminary experiments plan.

  2. A 12 GHz wavelength spacing multi-wavelength laser source for wireless communication systems

    NASA Astrophysics Data System (ADS)

    Peng, P. C.; Shiu, R. K.; Bitew, M. A.; Chang, T. L.; Lai, C. H.; Junior, J. I.

    2017-08-01

    This paper presents a multi-wavelength laser source with 12 GHz wavelength spacing based on a single distributed feedback laser. A light wave generated from the distributed feedback laser is fed into a frequency shifter loop consisting of 50:50 coupler, dual-parallel Mach-Zehnder modulator, optical amplifier, optical filter, and polarization controller. The frequency of the input wavelength is shifted and then re-injected into the frequency shifter loop. By re-injecting the shifted wavelengths multiple times, we have generated 84 optical carriers with 12 GHz wavelength spacing and stable output power. For each channel, two wavelengths are modulated by a wireless data using the phase modulator and transmitted through a 25 km single mode fiber. In contrast to previously developed schemes, the proposed laser source does not incur DC bias drift problem. Moreover, it is a good candidate for radio-over-fiber systems to support multiple users using a single distributed feedback laser.

  3. The 94 GHz Cloud Radar System on a NASA ER-2 Aircraft

    NASA Technical Reports Server (NTRS)

    Li, Lihua; Heymsfield, Gerald M.; Racette, Paul E.; Tian, Lin; Zenker, Ed

    2003-01-01

    The 94-GHz (W-band) Cloud Radar System (CRS) has been developed and flown on a NASA ER-2 high-altitude (20 km) aircraft. The CRS is a fully coherent, polarimeteric Doppler radar that is capable of detecting clouds and precipitation from the surface up to the aircraft altitude in the lower stratosphere. The radar is especially well suited for cirrus cloud studies because of its high sensitivity and fine spatial resolution. This paper describes the CRS motivation, instrument design, specifications, calibration, and preliminary data &om NASA s Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE) field campaign. The unique combination of CRS with other sensors on the ER-2 provides an unprecedented opportunity to study cloud radiative effects on the global energy budget. CRS observations are being used to improve our knowledge of atmospheric scattering and attenuation characteristics at 94 GHz, and to provide datasets for algorithm implementation and validation for the upcoming NASA CloudSat mission that will use a 94-GHz spaceborne cloud radar to provide the first direct global survey of the vertical structure of cloud systems.

  4. The Surprising Complexity of Diffuse and Translucent Clouds Toward SGR B2: Diatomics and COMs from 4 GHz to 1.2 THz

    NASA Astrophysics Data System (ADS)

    McGuire, Brett A.; Corby, Joanna F.; Martin-Drumel, Marie-Aline; Schilke, P.; McCarthy, Michael C.; Remijan, Anthony

    2017-06-01

    Many diffuse and translucent clouds lie along the line of sight between Earth and the Galactic Center that can be probed through molecular absorption at characteristic velocities. We highlight results of a study of diffuse and translucent clouds along the line of sight to Sgr B2, including SOFIA observations of SH near 1.4 THz and GBT PRIMOS observations from 4 to 50 GHz. We find significant variation in the chemical conditions within these clouds, and the abundances do not appear to correlate with the total optical depth. Additionally, from the GBT observations, we report the first detections of multiple complex organic molecules (COMs) in diffuse and translucent clouds, including CH_3CN, HC_3N, CH_3CHO, and NH_2CHO. We compare the GBT results to complementary observations of SH, H_2S, and others at mm, sub-mm, and THz frequencies from the NRAO 12m, Herschel HIFI, and SOFIA facilities, and comment on the insights into interstellar sulfur chemistry which is currently not well constrained.

  5. Seamless integration of 100-G wire line and 100-GHz wireless link system

    NASA Astrophysics Data System (ADS)

    Dong, Ze; Yu, Jianjun; Li, Xinying; Chi, Nan

    2013-01-01

    In this invited paper, we experimentally demonstrate a seamlessly integrated fiber-wireless system that delivers 108-Gb/s signal through 80-km fiber and 1-m wireless transport over free-space at 100 GHz, adopting polarization-divisionmultiplexing quadrature-phase-shift-keying (PDM-QPSK) modulation and heterodyning coherent detection. The X- and Y-polarization baseband components of the optical PDM-QPSK are simultaneously up-converted to 100-GHz wireless carriers by optical polarization-diversity heterodyne beating, and then independently transmitted and received by two pairs of transmitter and receiver antennas, which forms a 2x2 multiple-input multiple-output (MIMO) wireless link. At the wireless receiver, two-stage down conversion is performed with firstly done in analog domain based on balanced mixer and sinusoidal radio frequency (RF) signal, and then in digital domain based on digital signal processing (DSP). MIMO signal de-multiplexing combined with optical polarization multiplexing and free space MIMO crosstalk is realized by constant modulus algorithm (CMA) in digital signal processing (DSP) part at the receiver. The bit-error ratio (BER) for the 108-Gb/s PDM-QPSK signal is less than the pre-forward-error-correction (pre-FEC) threshold of 3.8x10-3 after both 1-m wireless delivery at 100 GHz and 80-km single-mode fiber-28 (SMF-28) transmission. To our knowledge, this is the first demonstration to realize 100-Gb/s signal delivery through both fiber and wireless links at 100GHz.

  6. An 8.4-GHz dual-maser front-end system for Parkes reimplementation

    NASA Astrophysics Data System (ADS)

    Trowbridge, D. L.; Loreman, J. R.; Brunzie, T. J.; Quinn, R.

    1990-02-01

    An 8.4-GHz front-end system consisting of a feedhorn, a waveguide feed assembly, dual masers, and downconverters was reimplemented at Parkes as part of the Parkes Canberra Telemetry Array for the Voyager Neptune encounter. The front-end system was originally assembled by the European Space Agency and installed on the Parkes antenna for the Giotto project. It was also used on a time-sharing basis by the Deep Space Network as part of the Parkes Canberra Telemetry Array to enhance the data return from the Voyager Uranus encounter. At the conclusion of these projects in 1986, part of the system was then shipped to JPL on loan for reimplementation at Parkes for the Voyager Neptune encounter. New design and implementation required to make the system operable at Parkes included new microwave front-end control cabinets, closed-cycle refrigeration monitor system, noise-adding radiometer system, front-end controller assembly, X81 local oscillator multiplier, and refurbishment of the original dual 8.4-GHz traveling-wave masers and waveguide feed system. The front-end system met all requirements during the encounter and was disassembled in October 1989 and returned to JPL.

  7. An 8.4-GHz dual-maser front-end system for Parkes reimplementation

    NASA Technical Reports Server (NTRS)

    Trowbridge, D. L.; Loreman, J. R.; Brunzie, T. J.; Quinn, R.

    1990-01-01

    An 8.4-GHz front-end system consisting of a feedhorn, a waveguide feed assembly, dual masers, and downconverters was reimplemented at Parkes as part of the Parkes Canberra Telemetry Array for the Voyager Neptune encounter. The front-end system was originally assembled by the European Space Agency and installed on the Parkes antenna for the Giotto project. It was also used on a time-sharing basis by the Deep Space Network as part of the Parkes Canberra Telemetry Array to enhance the data return from the Voyager Uranus encounter. At the conclusion of these projects in 1986, part of the system was then shipped to JPL on loan for reimplementation at Parkes for the Voyager Neptune encounter. New design and implementation required to make the system operable at Parkes included new microwave front-end control cabinets, closed-cycle refrigeration monitor system, noise-adding radiometer system, front-end controller assembly, X81 local oscillator multiplier, and refurbishment of the original dual 8.4-GHz traveling-wave masers and waveguide feed system. The front-end system met all requirements during the encounter and was disassembled in October 1989 and returned to JPL.

  8. The 18 and 30 GHz fixed service communications satellite system study. [to determine the cost and performance characteristics

    NASA Technical Reports Server (NTRS)

    Bronstein, L. M.

    1979-01-01

    The use of the 18 and 30 GHz bands for fixed service satellite communications is examined. The cost and performance expected of 18 and 30 GHz hardware is assessed, selected trunking and direct to user concepts are optimized, and the cost of these systems are estimated. The effect of rain attenuation on the technical and economic viability of the system and methods circumventing the problem are discussed. Technology developments are investigated and cost estimates of these developments are presented.

  9. A Compact 600 GHz Electronically Tunable Vector Measurement System for Submillimeter Wave Imaging

    NASA Technical Reports Server (NTRS)

    Dengler, Robert J.; Maiwald, Frank; Siegel, Peter H.

    2006-01-01

    A compact submillimeter wave transmission / reflection measurement system has been demonstrated at 560-635 GHz, with electronic tuning over the entire band. Maximum dynamic range measured at a single frequency is 90 dB (60 dB typical), and phase noise is less than +/- 2(deg). By using a frequency steerable lens at the source output and mixer input, the frequency agility of the system can be used to scan the source and receive beams, resulting in near real-time imaging capability using only a single pixel.

  10. Optical-network-connected multi-channel 96-GHz-band distributed radar system

    NASA Astrophysics Data System (ADS)

    Kanno, Atsushi; Kuri, Toshiaki; Kawanishi, Tetsuya

    2015-05-01

    The millimeter-wave (MMW) radar is a promising candidate for high-precision imaging because of its short wavelength and broad range of available bandwidths. In particular in the frequency range of 92-100 GHz, which is regulated for radiolocation, an atmospheric attenuation coefficient less than 1 dB/km limits the imaging range. Therefore, a combination of MMW radar and distributed antenna system directly connected to optical fiber networks can realize both high-precision imaging and large-area surveillance. In this paper, we demonstrate a multi-channel MMW frequency-modulated continuous-wave distributed radar system connected to an analog radio-over-fiber network.

  11. The 30/20 GHz flight experiment system, phase 2. Volume 1: Executive summary

    NASA Astrophysics Data System (ADS)

    Bronstein, L.; Kawamoto, Y.; Ribarich, J. J.; Scope, J. R.; Forman, B. J.; Bergman, S. G.; Reisenfeld, S.

    1981-07-01

    Summary information on the final communication system design, communication payload, space vehicle, and development plan for the 30/20 GHz flight experiment will be installed on the LEASAT spacecraft which will be placed into orbit from the space shuttle cargo bay. The communication concept has two parts: a truck service and a customer premise service (CPS). The trucking system serves four spot beams which are interconnected in a satellite switched time division multiple access mode by an IF switch matrix. The CPS covers two large areas of the eastern United States with a pair of scanning beams.

  12. A Compact 600 GHz Electronically Tunable Vector Measurement System for Submillimeter Wave Imaging

    NASA Technical Reports Server (NTRS)

    Dengler, Robert J.; Maiwald, Frank; Siegel, Peter H.

    2006-01-01

    A compact submillimeter wave transmission / reflection measurement system has been demonstrated at 560-635 GHz, with electronic tuning over the entire band. Maximum dynamic range measured at a single frequency is 90 dB (60 dB typical), and phase noise is less than +/- 2(deg). By using a frequency steerable lens at the source output and mixer input, the frequency agility of the system can be used to scan the source and receive beams, resulting in near real-time imaging capability using only a single pixel.

  13. A system analysis of the 13.3 GHz scatterometer. [antenna patterns and signal transmission

    NASA Technical Reports Server (NTRS)

    Wang, J. R.

    1977-01-01

    The performance of the 13.3 GHz airborne scatterometer system which is used as a microwave remote sensor to detect moisture content of soil is analyzed with respect to its antenna pattern, the signal flow in the receiver data channels, and the errors in the signal outputs. The operational principle and the sensitivity of the system, as well as data handling are also described. The dielectric property of the terrain surface, as far as the scatterometer is concerned, is contained in the assumed forms of the functional dependence of the backscattering coefficient of the incident angle.

  14. A 230-GHz radiometer system employing a second-harmonic mixer

    NASA Technical Reports Server (NTRS)

    Goldsmith, P. F.; Plambeck, R. L.

    1976-01-01

    A radiometer system for use in the 1.3 mm region has been constructed and used for radio astronomical observations. A second-harmonic mixer employing a single Schottky diode downconverts the incident power to an IF frequency of about 1400 MHz. The measured double-sideband system noise temperature is 6000 K (noise figure = 13 dB) and the double-sideband mixer conversion loss is calculated to be 10 dB. The mixer is tunable over a range of at least 15 GHz.

  15. The 30/20 GHz flight experiment system, phase 2. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Bronstein, L.; Kawamoto, Y.; Ribarich, J. J.; Scope, J. R.; Forman, B. J.; Bergman, S. G.; Reisenfeld, S.

    1981-01-01

    Summary information on the final communication system design, communication payload, space vehicle, and development plan for the 30/20 GHz flight experiment will be installed on the LEASAT spacecraft which will be placed into orbit from the space shuttle cargo bay. The communication concept has two parts: a truck service and a customer premise service (CPS). The trucking system serves four spot beams which are interconnected in a satellite switched time division multiple access mode by an IF switch matrix. The CPS covers two large areas of the eastern United States with a pair of scanning beams.

  16. Lewis Investigates Frequency Sharing Between Future NASA Space Systems and Local Multipoint Distribution Systems in the 27-GHz Band

    NASA Technical Reports Server (NTRS)

    1997-01-01

    At the request of the Federal Communications Commission (FCC), the NASA Lewis Research Center undertook an intensive study to examine the feasibility of frequency sharing between future NASA space services and proposed Local Multipoint Distribution Systems (LMDS) in the 25.25- to 27.5-GHz band. This follows NASA's earlier involvement in the FCC's 1994 Negotiated Rule Making Committee which studied frequency sharing between Ka-band Fixed Satellite Services and LMDS in the 27.5- to 29.5-GHz band. LMDS is a terrestrial, cellular, wireless communication service primarily intended to provide television distribution from hub stations located within relatively small cells to fixed subscriber receivers. Some proposed systems, however, also plan to offer interactive services via subscriber-to-hub transmissions. LMDS providers anticipate that their systems will be a cost-effective alternative to cable television systems, especially in urban areas. LMDS proponents have expressed an interest in using frequencies below 27.5 GHz. NASA, however, plans to operate three types of space systems below 27.5 GHz. The H, I, and J follow-on satellites for the Tracking and Data Relay Satellite System (TDRSS), which are planned for launch beginning in 1999, are designed to receive high-data-rate transmissions (up to 800 Mbps) from low-Earth orbiting "user" spacecraft in the 25.25- to 27.5-GHz band. In this case, the potential interference is the aggregate interference from LMDS transmitters (both hubs and subscribers) into the TDRSS tracking receive beams as they sweep over the Earth's surface while tracking lower altitude user spacecraft.

  17. Ground-based atmospheric water vapor monitoring system with spectroscopy of radiation in 20-30 GHz and 50-60 GHz bands

    NASA Astrophysics Data System (ADS)

    Nagasaki, Takeo; Tajima, Osamu; Araki, Kentaro; Ishimoto, Hiroshi

    2016-07-01

    We propose a novel ground-based meteorological monitoring system. In the 20{30 GHz band, our system simultaneously measures a broad absorption peak of water vapor and cloud liquid water. Additional observation in the 50{60 GHz band obtains the radiation of oxygen. Spectral results contain vertical profiles of the physical temperature of atmospheric molecules. We designed a simple method for placing the system atop high buildings and mountains and on decks of ships. There is a simple optical system in front of horn antennas for each frequency band. A focused signal from a reflector is separated into two polarized optical paths by a wire grid. Each signal received by the horn antenna is amplified by low-noise amplifiers. Spectra of each signal are measured as a function of frequency using two analyzers. A blackbody calibration source is maintained at 50 K in a cryostat. The calibration signal is led to each receiver via the wire grid. The input path of the signal is selected by rotation of the wire grid by 90°, because the polarization axis of the reflected path and axis of the transparent path are orthogonal. We developed a prototype receiver and demonstrated its performance using monitoring at the zenith.

  18. ECH system using an 88 GHz gyrotron for the WT-3 Tokamak

    SciTech Connect

    Maekawa, T.; Terumichi, Y.; Yoshimura, S.; Matsunaga, K.

    1996-02-01

    A new ECH/ECCD system using an 88GHz gyrotron for the WT-3 Tokamak ({ital R}{sub 0}=65{ital cm}, {ital a}=20{ital cm}, {ital B}{sub {ital T}0}{le}1.75{ital T}) is under making. Taking advantage of a relatively short wavelength and the Gaussian beam output mode, we plan ECH/ECCD experiments with a strongly focused beam in order to achieve local modification of the electron temperature and current profiles for investigation of MHD instabilities. {copyright} {ital 1996 American Institute of Physics.}

  19. A 20 GHz low noise, low cost receiver for digital satellite communication system, ground terminal applications

    NASA Technical Reports Server (NTRS)

    Allen, Glen

    1988-01-01

    A 45 month effort for the development of a 20 GHz, low-noise, low-cost receiver for digital, satellite communication system, ground terminal applications is discussed. Six proof-of-concept receivers were built in two lots of three each. Performance was generally consistent between the two lots. Except for overall noise figure, parameters were within or very close to specification. While noise figure was specified as 3.5 dB, typical performance was measured at 3.0 to 5.5 dB, over the full temperature range of minus 30 C to plus 75 C.

  20. A cooperative transponder system for improved traffic safety, localizing road users in the 5 GHz band

    NASA Astrophysics Data System (ADS)

    Schaffer, B.; Kalverkamp, G.; Chaabane, M.; Biebl, E. M.

    2012-09-01

    We present a multi-user cooperative mobile transponder system which enables cars to localize pedestrians, bicyclists and other road users in order to improve traffic safety. The system operates at a center frequency of 5.768 GHz, offering the ability to test precision localization technology at frequencies close to the newly designated automotive safety related bands around 5.9 GHz. By carrying out a roundtrip time of flight measurement, the sensor can determine the distance from the onboard localization unit of a car to a road user who is equipped with an active transponder, employing the idea of a secondary radar and pulse compression. The onboard unit sends out a pseudo noise coded interrogation pulse, which is answered by one or more transponders after a short waiting time. Each transponder uses a different waiting time in order to allow for time division multiple access. We present the system setup as well as range measurement results, achieving an accuracy up to centimeters for the distance measurement and a range in the order of hundred meters. We also discuss the effect of clock drift and offset on distance accuracy for different waiting times and show how the system can be improved to further increase precision in a multiuser environment.

  1. 3 MW, 110 GHz ECH system for the DIII-D tokamak

    SciTech Connect

    Callis, R.W.; Lohr, J.; Ponce, D.; Harris, T.E.; O`Neill, R.C.; Remsen, D.B.; Prater, R.; Luce, T.C.

    1998-07-01

    To support the Advanced Tokamak (AT) operating regimes in the DIII-D tokamak, methods need to be developed to control the current and pressure profiles across the plasma discharge. In particular, AT plasmas require substantial off-axis current in contrast to normal tokamak discharges where the current peaks on-axis. An effort is under way to use Electron Cyclotron Current Drive (ECCD) as a method of sustaining the off-axis current in AT plasmas. The first step in this campaign is the installation of three megawatts of electron cyclotron heating power. This involves the installation of three rf systems operating at 110 GHz, the second harmonic resonance frequency on DIII-D, with each system generating nominally 1 MW. The three systems will use one GYCOM (Russian) gyrotron and two CPI (formerly Varian) gyrotrons, all with windowless evacuated corrugated low loss transmission lines. The first two of three 1 MW ECH systems is operating routinely at DIII-D with injected power at 110 GHz of approximately 1.5 MW with good power accountability. Transport experiments using modulated ECH have been performed confirming the power deposition location. On-axis and off-axis current drive experiments have been successfully performed with on-axis ECCD currents of 170 kA being observed.

  2. Orbital diversity in resource-shared satellite communication systems above 10 GHz

    NASA Astrophysics Data System (ADS)

    Matricciani, Emilio

    1987-05-01

    The paper discusses orbital diversity (OD) used as the common resource in a satellite communication adaptive system affected by rain attenuation. To give quantitative results, a simulation at 20/30 GHz is performed with a mathematical model; also, some experimental results are shown. OD performance for a single site is first discussed. Then the probabilistic theory for adaptive systems is built up and applied to the simulated system. System reconfigurability and switchover are discussed, considering only transfer medium propagation characteristics, without addressing the important overall economic aspects. The comparison to frequency diversity employed in the same system shows that OD may be competitive if it is used in conjunction with radio links with unequal power margins, and a low i/S ratio (number of spare channels over number of assisted stations) is required.

  3. Higher-order modulations of fs laser pulses for GHz frequency domain photon migration system.

    PubMed

    Lin, Huang-Yi; Cheng, Nanyu; Tseng, Sheng-Hao; Chan, Ming-Che

    2014-02-24

    Except the fundamental modulation frequency, by higher-order-harmonic modulations of mode-locked laser pulses and a simple frequency demodulation circuit, a novel approach to GHz frequency-domain-photon-migration (FDPM) system was reported. With this novel approach, a wide-band modulation frequency comb is available without any external modulation devices and the only electronics to extract the optical attenuation and phase properties at a selected modulation frequency in FDPM systems are good mixers and lock-in devices. This approach greatly expands the frequency range that could be achieved by conventional FDPM systems and suggests that our system could extract much more information from biological tissues than the conventional FDPM systems. Moreover, this demonstration will be beneficial for discerning the minute change of tissue properties.

  4. Quasi-optical 140 GHz ECRH system on the advanced W VII-AS stellarator

    SciTech Connect

    Henle, W.; Kasparek, W.; Kumric, H.; Mueller, G.A.; Schueller, P.G.; Thumm, M. ); Erckmann, V. )

    1989-07-01

    A design is presented of a 140 GHz 2nd harmonic electron cyclotron resonance heating (ECRH) system to be used on the advanced stellarator W VII-AS at IPP Garching. The primary objectives of these ECRH experiments will be (1) to extend the density range for ECRH and for combined heating (NBI and/or ICRH), (2) to investigate the local electron heat transport in high density plasmas by the heat-wave technique, (3) to develop new millimeter-wave transmission line concepts and antenna systems for reactor-compatible multi-megawatt heating of future large-size stellarators. The planned 140 GHz ECRH facility will use a 200 kW/100 to 200 ms TEO3-mode gyrotron from KfK Karlsruhe combined with a quasi-optical fundamental Gaussian-mode transmission system employing focusing metallic mirrors as phase correcting elements. The unpolarized gyrotron output mode will be converted directly into the linearly polarized Gaussian free-space beam with the help of a quasi-optical coupler. A universal quasi-optical polarizer will provide the optimum polarization state in order to get the best accessibility conditions to the plasma.

  5. NASA's climate data system primer, version 1.2

    NASA Technical Reports Server (NTRS)

    Closs, James W.; Reph, Mary G.; Olsen, Lola M.

    1989-01-01

    This is a beginner's manual for NASA's Climate Data System (NCDS), an interactive scientific information management system that allows one to locate, access, manipulate, and display climate-research data. Additional information on the use of the system is available from the system itself.

  6. The 60 GHz antenna system analyses for intersatellite links, phase A

    NASA Technical Reports Server (NTRS)

    1984-01-01

    A tradeoff study for 60 GHz antenna systems applicable to an advanced Tracking and Data Acquisition System is also discussed. A conceptual design of a preferred antenna system is also discussed. The tradeoff results for four types of antenna systems are presented: (1) Reflector/fixed feed, (2) Mechanical scan, (3) Electronic scan; and (4) Hybrid mechanical/electronic scan. The 12 candidate antennas were assessed on the basis of a preliminary design and a performance analysis then were scored against 15 weighted parameters. This process resulted in the ranking of the 12 candidates for the two applications, namely, for the geostationary TDAS only with a narrow field of view and for low orbit user satellites with a wide field of view.

  7. A Megawatt-level 28z GHz Heating System For The National Spherical Torus Experiment Upgrade

    SciTech Connect

    Taylor, Gary

    2014-04-01

    The National Spherical Torus Experiment Upgrade (NSTX-U) will operate at axial toroidal fields of < 1 T and plasma currents, Ip < 2 MA. The development of non-inductive (NI) plasmas is a major long-term research goal for NSTX-U. Time dependent numerical simulations of 28 GHz electron cyclotron (EC) heating of low density NI start-up plasmas generated by Coaxial Helicity Injection (CHI) in NSTX-U predict a significant and rapid increase of the central electron temperature (Te(0)) before the plasma becomes overdense. The increased Te(0) will significantly reduce the Ip decay rate of CHI plasmas, allowing the coupling of fast wave heating and neutral beam injection. A megawatt-level, 28 GHz electron heating system is planned for heating NI start-up plasmas in NSTX-U. In addition to EC heating of CHI start-up discharges, this system will be used for electron Bernstein wave (EBW) plasma start-up, and eventually for EBW heating and current drive during the Ip flattop.

  8. A Megawatt-level 28z GHz Heating System For The National Spherical Torus Experiment Upgrade

    SciTech Connect

    Taylor, Gary

    2014-04-01

    The National Spherical Torus Experiment Upgrade (NSTX-U) will operate at axial toroidal fields of < 1 T and plasma currents, Ip < 2 MA. The development of non-inductive (NI) plasmas is a major long-term research goal for NSTX-U. Time dependent numerical simulations of 28 GHz electron cyclotron (EC) heating of low density NI start-up plasmas generated by Coaxial Helicity Injection (CHI) in NSTX-U predict a significant and rapid increase of the central electron temperature (Te(0)) before the plasma becomes overdense. The increased Te(0) will significantly reduce the Ip decay rate of CHI plasmas, allowing the coupling of fast wave heating and neutral beam injection. A megawatt-level, 28 GHz electron heating system is planned for heating NI start-up plasmas in NSTX-U. In addition to EC heating of CHI start-up discharges, this system will be used for electron Bernstein wave (EBW) plasma start-up, and eventually for EBW heating and current drive during the Ip flattop.

  9. A 28 GHz ECH/EBW System for the Proto-MPEX plasma source

    NASA Astrophysics Data System (ADS)

    Bigelow, Tim; Caughman, John; Campbell, Ian; Diem, Stephanie; Dukes, Carl; Goulding, Richard; Killough, Stephen; Rapp, Juergen

    2015-11-01

    The Prototype Materials Plasma Exposure Experiment (Proto-MPEX) is a linear high-intensity RF plasma source that requires plasma electron heating in overdense conditions to provide target parameters in the density and temperature range needed for plasma facing material studies. In Proto-MPEX, a dense helicon plasma is produced by 13.56 MHz RF power and is further heated by 28 GHz microwaves via Electron Bernstein Waves (EBW). A 28 GHz 200 kW cw gyrotron system from earlier experiments at ORNL provides the microwave power and has been successful to date at generating >150 kW in short pulses into a dummy load and >100 kW into the plasma via a 88.9 mm corrugated waveguide system and compact launcher near the plasma edge. For successful coupling via EBW into an overdense plasma, the launcher must be optimized and if possible have adjustable launch angle to maximize the efficiency. Modeling of the EBW coupling has been performed using the GENRAY-C code for the expected plasma profile in order to determine the best beam profile and polarization requirements. A compact HE11 mode waveguide launch with adjustable launch angle has been installed that is tightly coupled to the plasma. The submitted manuscript has been authored by a contractor of the U.S. Government under contract DE-AC05-00OR22725.

  10. Classical models of the spin 1/2 system

    NASA Astrophysics Data System (ADS)

    Salazar-Lazaro, Carlos H.

    We proposed a Quaternionic mechanical system motivated by the Foucault pendulum as a classical model for the dynamics of the spin ½ system. We showed that this mechanical system contains the dynamics of the spin state of the electron under a uniform magnetic field as it is given by the Schrodinger-Pauli-Equation (SPE). We closed with a characterization of the dynamics of this generalized classical system by showing that it is equivalent with the dynamics of the Schrodinger Pauli Equation as long as the solutions to the generalized classical system are roots of the Lagrangian, that is the condition L = 0 holds.

  11. LARP LHC 4.8 GHZ Schottky System Initial Commissioning with Beam

    SciTech Connect

    Pasquinelli, Ralph J.; Jansson, Andreas; Jones, O.Rhodri; Caspers, Fritz; /CERN

    2011-03-18

    The LHC Schottky system consists for four independent 4.8 GHz triple down conversion receivers with associated data acquisition systems. Each system is capable of measuring tune, chromaticity, momentum spread in either horizontal or vertical planes; two systems per beam. The hardware commissioning has taken place from spring through fall of 2010. With nominal bunch beam currents of 10{sup 11} protons, the first incoherent Schottky signals were detected and analyzed. This paper will report on these initial commissioning results. A companion paper will report on the data analysis curve fitting and remote control user interface of the system. The Schottky system for the LHC was proposed in 2004 under the auspices of the LARP collaboration. Similar systems were commissioned in 2003 in the Fermilab Tevatron and Recycler accelerators as a means of measuring tunes noninvasively. The Schottky detector is based on the stochastic cooling pickups that were developed for the Fermilab Antiproton Source Debuncher cooling upgrade completed in 2002. These slotted line waveguide pickups have the advantage of large aperture coupled with high beam coupling characteristics. For stochastic cooling, wide bandwidths are integral to cooling performance. The bandwidth of slotted waveguide pickups can be tailored by choosing the length of the pickup and slot spacing. The Debuncher project covered the 4-8 GHz band with eight bands of pickups, each with approximately 500 MHz of bandwidth. For use as a Schottky detector, bandwidths of 100-200 MHz are required for gating, resulting in higher transfer impedance than those used for stochastic cooling. Details of hardware functionality are reported previously.

  12. Radiofrequency testing of satellite segment of simulated 30/20 GHz satellite communications system

    NASA Technical Reports Server (NTRS)

    Leonard, R. F.; Kerczewski, R.

    1985-01-01

    A laboratory communications system has been developed that can serve as a test bed for the evaluation of advanced microwave (30/20 GHz) components produced under NASA technology programs. The system will ultimately permit the transmission of a stream of high-rate (220 Mbps) digital data from the originating user, through a ground terminal, through a hardware-simulated satellite, to a receiving ground station, to the receiving user. This report contains the results of radiofrequency testing of the satellite portion of that system. Data presented include output spurious responses, attainable signal-to-noise ratios, a baseline power budget, usable frequency bands, phase and amplitude response data for each of the frequency bands, and the effects of power level variation.

  13. Power Accountability with 1 MW 110 GHz Gyrotron System on the DIII--D Tokamak

    NASA Astrophysics Data System (ADS)

    Zhang, Daqing; Lohr, John; Tooker, J. W.; Ponce, Dan; Callis, R. W.

    1996-11-01

    A new gyrotron system (110 GHz, 1 MW, 2 sec) has been built for the DIII--D tokamak. Before the ECH physics experiments were carried out on DIII--D, the power produced by the gyrotron was measured carefully as well as the power absorbed by parts of the system such as in the gyrotron window, mirror optics unit, miter bends, and dummy loads, for different pulse durations. The maximum output power achieved up to now is 885 kW for 500 msec pulse length. The gyrotron generation efficiency is 37%, very close to the optimum operation parameters, and the whole system's efficiency is 29%. The output mode and frequency of the gyrotron was also measured. Detailed experimental results will be presented.

  14. Radiofrequency testing of satellite segment of simulated 30/20 GHz satellite communications system

    NASA Astrophysics Data System (ADS)

    Leonard, R. F.; Kerczewski, R.

    1985-11-01

    A laboratory communications system has been developed that can serve as a test bed for the evaluation of advanced microwave (30/20 GHz) components produced under NASA technology programs. The system will ultimately permit the transmission of a stream of high-rate (220 Mbps) digital data from the originating user, through a ground terminal, through a hardware-simulated satellite, to a receiving ground station, to the receiving user. This report contains the results of radiofrequency testing of the satellite portion of that system. Data presented include output spurious responses, attainable signal-to-noise ratios, a baseline power budget, usable frequency bands, phase and amplitude response data for each of the frequency bands, and the effects of power level variation.

  15. Terahertz MMICs and Antenna-in-Package Technology at 300 GHz for KIOSK Download System

    NASA Astrophysics Data System (ADS)

    Tajima, Takuro; Kosugi, Toshihiko; Song, Ho-Jin; Hamada, Hiroshi; El Moutaouakil, Amine; Sugiyama, Hiroki; Matsuzaki, Hideaki; Yaita, Makoto; Kagami, Osamu

    2016-12-01

    Toward the realization of ultra-fast wireless communications systems, the inherent broad bandwidth of the terahertz (THz) band is attracting attention, especially for short-range instant download applications. In this paper, we present our recent progress on InP-based THz MMICs and packaging techniques based on low-temperature co-fibered ceramic (LTCC) technology. The transmitter MMICs are based on 80-nm InP-based high electron mobility transistors (HEMTs). Using the transmitter packaged in an E-plane split-block waveguide and compact lens receiver packaged in LTCC multilayered substrates, we tested wireless data transmission up to 27 Gbps with the simple amplitude key shifting (ASK) modulation scheme. We also present several THz antenna-in-packaging solutions based on substrate integrated waveguide (SIW) technology. A vertical hollow (VH) SIW was applied to a compact medium-gain SIW antenna and low-loss interconnection integrated in LTCC multi-layer substrates. The size of the LTCC antennas with 15-dBi gain is less than 0.1 cm3. For feeding the antenna, we investigated an LTCC-integrated transition and polyimide transition to LTCC VH SIWs. These transitions exhibit around 1-dB estimated loss at 300 GHz and more than 35 GHz bandwidth with 10-dB return loss. The proposed package solutions make antennas and interconnections easy to integrate in a compact LTCC package with an MMIC chip for practical applications.

  16. A 60GHz-Band 3-Dimensional System-in-Package Transmitter Module with Integrated Antenna

    NASA Astrophysics Data System (ADS)

    Suematsu, Noriharu; Yoshida, Satoshi; Tanifuji, Shoichi; Kameda, Suguru; Takagi, Tadashi; Tsubouchi, Kazuo

    A low cost, ultra small Radio Frequency (RF) transceiver module with integrated antenna is one of the key technologies for short range millimeter-wave wireless communication. This paper describes a 60GHz-band transmitter module with integrated dipole antenna. The module consists of three pieces of low-cost organic resin substrate. These substrates are vertically stacked by employing Cu ball bonding 3-dimensional (3-D) system-in-package (SiP) technology and the MMIC's are mounted on each organic substrates by using Au-stud bump bonding (SBB) technique. The planer dipole antenna is fabricated on the top of the stacked organic substrate to avoid the influence of the grounding metal on the base substrate. At 63GHz, maximum actual gain of 6.0dBi is obtained for fabricated planar dipole antenna. The measured radiation patterns are agreed with the electro-magnetic (EM) simulated result, therefore the other RF portion of the 3-D front-end module, such as flip chip mounted IC's on the top surface of the module, does not affect the antenna characteristics. The results show the feasibility of millimeter-wave low cost, ultra small antenna integrated module using stacked organic substrates.

  17. RF system for a 30 GHz, 5 TeV linear collider based on conventional technology

    SciTech Connect

    Wilson, P.B.; Raubenheimer, T.; Ruth, R.D.

    1997-07-01

    In order that it may be built within a reasonable length and with reasonable ac power consumption, a 5 TeV linear collider must employ an accelerating gradient and rf frequency which are both higher than for present 1 TeV collider designs. The required rf power per meter, which will also be higher than for 1 TeV designs, can be provided either by relatively conventional rf technology or by a two-beam scheme such as that proposed for CLIC. In this paper the first alternative, a 30 GHz rf system employing microwave tube power sources together with rf pulse compression, is described which produces an accelerating gradient on the order of 200 MV per meter. Limitations on the peak power that can be obtained from conventional klystrons as a function of frequency are discussed; it is found that such klystrons are only marginally adequate as a power source at 30 GHz. Several alternative rf sources, such as multiple-beam klystrons, sheet-beam klystrons, gyroklystrons and annular-beam ubitrons are described which are capable of providing the required power, after pulse compression, of about 600 MW per meter.

  18. Inter-BSs virtual private network for privacy and security enhanced 60 GHz radio-over-fiber system

    NASA Astrophysics Data System (ADS)

    Zhang, Chongfu; Chen, Chen; Zhang, Wei; Jin, Wei; Qiu, Kun; Li, Changchun; Jiang, Ning

    2013-06-01

    A novel inter-basestations (inter-BSs) based virtual private network (VPN) for the privacy and security enhanced 60 GHz radio-over-fiber (RoF) system using optical code-division multiplexing (OCDM) is proposed and demonstrated experimentally. By establishing inter-BSs VPN overlaying the network structure of a 60 GHz RoF system, the express and private paths for the communication of end-users under different BSs can be offered. In order to effectively establish the inter-BSs VPN, the OCDM encoding/decoding technology is employed in the RoF system. In each BS, a 58 GHz millimeter-wave (MMW) is used as the inter-BSs VPN channel, while a 60 GHz MMW is used as the common central station (CS)-BSs communication channel. The optical carriers used for the downlink, uplink and VPN link transmissions are all simultaneously generated in a lightwave-centralized CS, by utilizing four-wave mixing (FWM) effect in a semiconductor optical amplifier (SOA). The obtained results properly verify the feasibility of our proposed configuration of the inter-BSs VPN in the 60 GHz RoF system.

  19. A 60GHz RoF(radio-over-fiber) transmission system based on PM modulator

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Liu, Yi; Wang, Wen-Ting

    2016-11-01

    As one of the most important applications of microwave photonic ROF (Radio over Fiber) system which combines the advantages of optical communication and wireless communication is a good candidate for broadband mobile Communication In this paper, we built and simulation a 60GHz RoF(Radio-over-Fiber) transmission system based on PM modulator. First, we introduce the PM-IM(Phase modulation to intensity modulation) modulation mechanisms by the breaking the phase balanced approach. This method solves the problem that the constant envelope (phase modulation signal) generated by the phase modulator can not be directly detected by a photo detector. A standard single-mode fiber (SMF) is connected input to the F-P(Fabry-Perot) optical filter, which is to achieve the PM-IM modulation conversion by changing the wavelength of the laser or the frequency of the modulation factor of the F-P optical filter to adapt to different fiber lengths and the signal transmission rate. These two methods which changing the phase relationship between the optical carrier and the optical side band can realize the ideal phase transition to obtain efficient and low loss modulation conversion. Finally, the simulation results show that different fiber lengths and the signal transmission rate configuration of different wavelength of the laser or the frequency of the modulation factor of the F-P optical filter, the BER performance and the eye diagram of the 60GHz RoF transmission system signals have been improved based on these PM-IM modulation methods.

  20. Conception and realization of a semiconductor based 240 GHz full 3D MIMO imaging system

    NASA Astrophysics Data System (ADS)

    Weisenstein, Christian; Kahl, Matthias; Friederich, Fabian; Haring Bolívar, Peter

    2017-02-01

    Multiple-input multiple-output (MIMO) imaging systems in the terahertz frequency range have a high potential in the field of non-destructive testing (NDT). With such systems it is possible to detect defects in composite materials, for example cracks or delaminations in fiber composites. To investigate mass-produced products it is necessary to study the objects in close to real-time on a conveyor without affecting the production cycle time. In this work we present the conception and realization of a 3D MIMO imaging system for in-line investigation of composite materials and structures. To achieve a lateral resolution of 1 mm, in order to detect such small defects in composite materials with a moderate number of elements, precise sensor design is crucial. In our approach we use the effective aperture concept. The designed sparse array consists of 32 transmitters and 30 receivers based on planar semiconductor components. High range resolution is achieved by an operating frequency between 220 GHz and 260 GHz in a stepped frequency continuous wave (SFCW) setup. A matched filter approach is used to simulate the reconstructed 3D image through the array. This allows the evaluation of the designed array geometry in regard of resolution and side lobe level. In contrast to earlier demonstrations, in which synthetic reconstruction is only performed in a 2D plane, an optics-free full 3D recon- struction has been implemented in our concept. Based on this simulation we designed an array geometry that enables to resolve objects with a resolution smaller than 1mm and moderate side lobe level.

  1. A 1 watt GaAs power amplifier for the NASA 30/20 GHz communication system

    NASA Technical Reports Server (NTRS)

    Goel, J.; Oransky, G.; Yuan, S.; Osullivan, P.; Burch, J.

    1982-01-01

    A multistage GaAs FET power amplifier, employing cascaded balanced stages using state-of-the-art 1/4, 1/2, and 1 watt devices, has been developed. A linear gain of 30 dB with 1.25 watts output has been achieved over a 17.7 to 19.4 GHz frequency band. The development and performance of the amplifier and its components are discussed.

  2. A multiple beam antenna concept for a 30/20 GHz satellite communications system

    NASA Technical Reports Server (NTRS)

    Forman, B. J.; Ohta, H. H.; Bronstein, L. M.

    1982-01-01

    Design and operational performance features of a NASA planned 30/30 GHz flight experiment communications system multiple-beam antenna (MBA) are described. The MBA is a shared aperture offset Cassegrain type with a main reflector diameter of 3 m and physically separated transmit and receive feeds. A planar frequency selective surface is employed which is transmissive to the receive signals and reflective to the transmit signals. Trade-offs and constraints in the MBA feed design are explored, noting the higher feed loss and complexity due to choosing variable power dividers for the beam forming network. Doublet beam coverage of the east coast of the continental U.S. is shown to be possible with a triangular lattice array of feed horns with aperture diameters and element spacings of two wavelengths. The doublet configuration requires ten times the components as a singlet array.

  3. Pierce-Wiggler electron beam system for 250 GHz GYRO-BWO: Final report

    SciTech Connect

    Pirkle, D.R.; Alford, C.W.; Anderson, M.H.; Garcia, R.F.; Legarra, J.R.; Nordquist, A.L.

    1989-01-01

    This final report summarizes the design and performance of the VUW-8028 Pierce-Wiggler electron beam systems, which can be used to power high frequency gyro-BWO's. The operator's manual for this gyro-BWO beamstick is included as appendix A. Researchers at Lawrence Livermore National Laboratory (LLNL) are developing a gyro-BWO with a center frequency of 250 GHz, 6% bandwidth, and 10 kV peak output power. The gyro-BWO will be used to drive a free electron laser amplifier at LLNL. The electron beam requirements of the gyro-BWO application are: Small beam size, .100 inch at 2500 gauss axial magnetic field; a large fraction of the electron energy in rotational velocity; ability to vary the electrons' axial velocity easily, for electronic tuning; and low velocity spread i.e. little variation in the axial velocities of the electrons in the interaction region. 1 ref., 13 figs.

  4. High capacity digital radio system family for the 18 GHz band

    NASA Astrophysics Data System (ADS)

    Otremba, K.; Steinkamp, J.; Thaler, H.-J.; Vogel, K.

    A highly modular family of large-capacity radio relay systems designed for the channel allocation plans of the 18-GHz band is presented. It makes use of 16-QAM and cochannel operation and provides high spectrum efficiency up to 6.8 b/s/Hz. Indirect modulation with spectrum shaping at IF based on a highly sophisticated SAW filter technology is combined with a multiple IF carrier approach, so that a transmission capacity of up to 1.12 Gb/s per RF and a maximum band capacity of 4.5 Gb/s is achieved. The intended use of this family is the extension of optical filter routes and application in densely meshed trunk and regional networks, especially where frequency coordination problems must be solved.

  5. The MTX computer control system for the 400 kilowatt 140 GHz gyrotron

    NASA Astrophysics Data System (ADS)

    Jackson, M. C.; Ferguson, S. W.; Petersen, D. E.

    1991-09-01

    A 400 kilowatt, 140 GHz gyrotron is employed on MTX as a source of direct plasma heating and, additionally, as a driver for a free electron laser, which is used for plasma heating. The control system that operates this gyrotron uses a new graphics oriented software system called TACL (Thaumaturgic Automated Control Logic) developed by the Continuous Electron Beam Accelerator Facility (CEBAF) and owned by DOE. This control language does not require a software specialist, but is easily handled by the engineer or technician working on the system. All control logic and custom displays are entered via graphics oriented editors and no actual lines of code need to be written. The graphics displays make the gyrotron operation quite simple and allow individual users to define displays to meet their own needs or develop one for a specific set of tests to be run. The system, additionally, can be used for logging functions, which have been found quite useful in tracking long term trends in vacion current and calorimetry of gyrotron cooling circuits. The system is composed of one computer (HP 9000 series 300) controlling multiple CAMAC crates located at the various components used in the system. A second series 300 computer is used as a supervisor and is located in the main tokamak control room. This supervisory computer provides remote operation of the gyrotron, and also provides a link to the microwave transport vacuum control (also TACL). The supervisory computer, additionally, is used as a subsystem status summary point for permissives to the gyrotron control system.

  6. Distribution of high-stability 10 GHz local oscillator over 100 km optical fiber with accurate phase-correction system.

    PubMed

    Wang, Siwei; Sun, Dongning; Dong, Yi; Xie, Weilin; Shi, Hongxiao; Yi, Lilin; Hu, Weisheng

    2014-02-15

    We have developed a radio-frequency local oscillator remote distribution system, which transfers a phase-stabilized 10.03 GHz signal over 100 km optical fiber. The phase noise of the remote signal caused by temperature and mechanical stress variations on the fiber is compensated by a high-precision phase-correction system, which is achieved using a single sideband modulator to transfer the phase correction from intermediate frequency to radio frequency, thus enabling accurate phase control of the 10 GHz signal. The residual phase noise of the remote 10.03 GHz signal is measured to be -70  dBc/Hz at 1 Hz offset, and long-term stability of less than 1×10⁻¹⁶ at 10,000 s averaging time is achieved. Phase error is less than ±0.03π.

  7. 76 FR 35176 - Operation of Radar Systems in the 76-77 GHz Band

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-16

    ... enhanced vehicular radar technologies in the 76-77 GHz band to improve collision avoidance and driver... August 1, 2011. FOR FURTHER INFORMATION CONTACT: Aamer Zain, Office of Engineering and Technology, (202... vehicular radar technologies in the 76-77 GHz band to improve collision avoidance and driver...

  8. Design, Development & Functional Validation of Magnets system in support of 42 GHz Gyrotron in India

    NASA Astrophysics Data System (ADS)

    Pradhan, S.; Raj, P.; Prasad, U.; Ghate, M.; Khristi, Y.; Panchal, A.; Bhavsar, D.; Banudha, M.; Kedia, S.; Sharma, A. N.; Kanabar, D.; Parghi, B.

    2017-07-01

    A multi institutional initiative is underway towards the development of 42 GHz, 200 kW gyrotron system in India under the frame work of Department of Science and Technology, Government of India. Indigenous realization comprising of design, fabrication, prototypes and functional validations of an appropriate Magnet System is one of the primary technological objective of these initiatives. The 42 GHz gyrotron magnet system comprises of a warm gun magnet, a NbTi/Cu based high homogenous superconducting cavity magnet and three warm collector magnets. The superconducting cavity magnet has been housed inside a low loss cryostat. The magnet system has been designed in accordance with gyrotron physics and engineering considerations respecting highly homogenous spatial field profile as well as maintaining steep gradient as per the compression and velocity ratios between the emission and resonator regions. The designed magnet system further ensures the co-linearity of the magnetic axis with that of the beam axis with custom winding techniques apart from a smooth collection of beam with the collector magnet profiles. The designed magnets have been wound after several R & D validations. The superconducting magnet has been housed inside a low loss designed cryostat with in-built radial and axial alignment flexibilities to certain extent. The cryostat further houses liquid helium port, liquid nitrogen ports, current communication ports, ports for monitoring helium level and other instrumentations apart from over-pressure safety intensive burst disks etc. The entire magnet system comprising of warm and superconducting magnets has been installed and integrated in the Gyrotron test set-up. The magnet system has been aligned in both warm and when the superconducting cavity magnet is cold. The integrated geometric axes have been experimentally ensured as well as the field profiles have been measured with the magnets being charged. Under experimental conditions, all magnets including

  9. Design of the Collective Thomson scattering (CTS) system by using 170-GHz gyrotron in the KSTAR

    NASA Astrophysics Data System (ADS)

    Park, Min; Kim, Sun-Ho; Kim, Sung-Kyu; Lee, Kyu-Dong; Wang, Son-Jong

    2014-10-01

    The physics of energetic ions is one of the primary subjects to be understood toward the realization of a nuclear fusion power plant. Collective Thomson scattering (CTS) offers the possibility to diagnose the fast ions and the alpha particles in burning plasmas. Spatially- and temporally-resolved one-dimensional velocity distributions of the fast ions can be obtained from the scattered radiation with fewer geometric constraints by utilizing millimeter waves from a high-power gyrotron as a probe beam. We studied the feasibility of CTS fast-ion measurements in the KSTAR by calculating the spectral density functions. Based on that, we suggest a design for the CTS system that uses the currently-operating 170-GHz gyrotron for electron cyclotron heating (ECH) and electron cyclotron current drive (ECCD) in the KSTAR. The CTS system is presented as two subsystems: the antenna system and the heterodyne receiver system. The design procedure for an off-axis ellipsoidal mirror is described, and the CTS system requirements are discussed.

  10. A Novel 24 GHz One-Shot, Rapid and Portable Microwave Imaging System

    NASA Technical Reports Server (NTRS)

    Ghasr, M. T.; Abou-Khousa, M. A.; Kharkovsky, S.; Zoughi, R.; Pommerenke, D.

    2008-01-01

    Development of microwave and millimeter wave imaging systems has received significant attention in the past decade. Signals at these frequencies penetrate inside of dielectric materials and have relatively small wavelengths. Thus. imaging systems at these frequencies can produce images of the dielectric and geometrical distributions of objects. Although there are many different approaches for imaging at these frequencies. they each have their respective advantageous and limiting features (hardware. reconstruction algorithms). One method involves electronically scanning a given spatial domain while recording the coherent scattered field distribution from an object. Consequently. different reconstruction or imaging techniques may be used to produce an image (dielectric distribution and geometrical features) of the object. The ability to perform this accuratev and fast can lead to the development of a rapid imaging system that can be used in the same manner as a video camera. This paper describes the design of such a system. operating at 2-1 GHz. using modulated scatterer technique applied to 30 resonant slots in a prescribed measurement domain.

  11. A 90GHz Bolometer Camera Detector System for the Green Bank Telescope

    NASA Technical Reports Server (NTRS)

    Benford, Dominic J.; Allen, Christine A.; Buchanan, Ernest D.; Chen, Tina C.; Chervenak, James A.; Devlin, Mark J.; Dicker, Simon R.; Forgione, Joshua B.

    2004-01-01

    We describe a close-packed, two-dimensional imaging detector system for operation at 90GHz (3.3mm) for the 100 m Green Bank Telescope (GBT) This system will provide high sensitivity (<1mjy in 1s rapid imaging (15'x15' to 250 microJy in 1 hr) at the world's largest steerable aperture. The heart of this camera is an 8x8 close packed, Nyquist-sampled array of superconducting transition edge sensor bolometers. We have designed and are producing a functional superconducting bolometer array system using a monolithic planar architecture and high-speed multiplexed readout electronics. With an NEP of approx. 2.10(exp 17) W/square root Hz, the TES bolometers will provide fast linear sensitive response for high performance imaging. The detectors are read out by and 8x8 time domain SQUID multiplexer. A digital/analog electronics system has been designed to enable read out by SQUID multiplexers. First light for this instrument on the GBT is expected within a year.

  12. A 90GHz Bolometer Camera Detector System for the Green Bank Telescope

    NASA Technical Reports Server (NTRS)

    Benford, Dominic J.; Allen, Christine A.; Buchanan, Ernest D.; Chen, Tina C.; Chervenak, James A.; Devlin, Mark J.; Dicker, Simon R.; Forgione, Joshua B.

    2004-01-01

    We describe a close-packed, two-dimensional imaging detector system for operation at 90GHz (3.3mm) for the 100 m Green Bank Telescope (GBT) This system will provide high sensitivity (<1mjy in 1s rapid imaging (15'x15' to 250 microJy in 1 hr) at the world's largest steerable aperture. The heart of this camera is an 8x8 close packed, Nyquist-sampled array of superconducting transition edge sensor bolometers. We have designed and are producing a functional superconducting bolometer array system using a monolithic planar architecture and high-speed multiplexed readout electronics. With an NEP of approx. 2.10(exp 17) W/square root Hz, the TES bolometers will provide fast linear sensitive response for high performance imaging. The detectors are read out by and 8x8 time domain SQUID multiplexer. A digital/analog electronics system has been designed to enable read out by SQUID multiplexers. First light for this instrument on the GBT is expected within a year.

  13. A 280GHz single-channel millimeter-wave interferometer system for KSTARa)

    NASA Astrophysics Data System (ADS)

    Nam, Y. U.; Lee, K. D.

    2008-10-01

    A 280GHz single-channel horizontal millimeter-wave interferometer system has been fabricated and installed for plasma electron density measurements on the Korea Superconducting Tokamak Advanced Research (KSTAR). A retractable cassette system has been adopted for deep positioning of the interferometer system on large cryostat. The cassette system contains a pneumatic vacuum window shutter and a beam focusing module. The focusing module consists of antennas and aluminum concave mirrors, where an incident beam is reflected on a specially designed carbon inner-wall tile. The module enhances receiving beam power and reduces phase errors due to unexpected beam reflections on a vacuum vessel. Microwave components such as oscillators and mixers are located 2m away from cryostat with a shielding box. Intermediate frequency signals generated by mixers are transmitted to a diagnostics room, and the phase difference between these signals is measured using a multifringe counting phase comparator. A beam path analysis has been performed for a triangular beam path geometry. An effective line-integrated density can be deduced from measured line-integrated density with these results. A beam path length error due to plasma refraction effect has been determined with various plasma conditions.

  14. Dual polarization VLBI observations of stellar binary systems at 5 GHz

    NASA Astrophysics Data System (ADS)

    Mutel, R. L.; Lestrade, J. F.; Preston, R. A.; Phillips, R. B.

    1985-02-01

    The binary systems Sigma CrB, SZ Psc, HR 1099, UX Ari, HR 5110, Algol, and Cyg X-1 are characterized in terms of marcsec-scale radio structure on the basis of dual-polarization observations at 4.969-4.997 GHz, obtained with an international VLBI array comprising the 100-m Effelsberg, 36-m Haystack, 42-m Green Bank, 26-m Fort Davis, 130-m-equivalent VLA, and 40-m Owens Valley telescopes (system temperatures 40-70 K) at 22-14 h UT on July 26-27, 1983. The data are presented in graphs and tables and discussed in detail. Single Gaussian brightness distributions with theta(FWHM) = 0.5-2.0 marcsec and brightness temperatures (2-200) x 10 to the 8th K are determined for four sources; core-halo structures are found for UX Ari and Algol; and an upper limit of 50 microarcsec is established for the angular separation of the regions of left and right circular polarization. The gross features seen in RS CVn systems are explained in terms of a simple expanding-coronal-loop model of flare events.

  15. Test and Commissioning of 82.6 GHz ECRH system on SST-1

    NASA Astrophysics Data System (ADS)

    Bora, D.; Sathyanarayana, K.; Shukla, B. K.; Chattopadhyay, Prabal; Srinivas, Y. S. S.; Khilar, P. L.; Kushwah, Mahesh; Rajnish, Kumar; Sugandhi, Ritesh; Singh, Manoj; Babu, Rajan; P, Jatin; G, Agrajit; Biswas, Prabal; D, Pragnesh; Kadia, B. R.; V, Chetan; Patel, Harshida; P, Dharmesh; Kirit, P.; Parmar, K. G.; Makwana, A. R.; Harsha, M.; Soni, Jignesh; Yadav, Vipin; Shmelev, M.; Belousov, V.; Kurbatov, V.; Belov, Yu; Tai, E.

    2005-01-01

    Electron Cyclotron Resonance Heating (ECRH) system will play an important role in plasma formation, heating and current drive in the Superconducting Steady state Tokamak (SST-1). Commissioning activity of the machine has been initiated. Many of the sub-systems have been prepared for the first plasma discharge. A radial and a top port have been allotted for low field side (LFS) and high field side (HFS) launch of O and X- modes in the plasma. The system is based on a gyrotron source operating at a frequency of 82.6±0.1GHz (GLGD-82.6/0.2) and capable of delivering 0.2 MW / 1000s with 17% duty cycle. The transmission line consisting of ~15 meters length 63.5mm corrugated wave guide, DC break, wave guide switch, mitre bend, polariser, bellows that terminates with a vacuum barrier CVD window. A beam launching system used to steer the microwave beam in the plasma volume is connected between the end of the transmission line and the tokamak radial and top ports. A VME based real time data acquisition and control (DAC) system is used for monitoring, acquisition and control. Hard-wired interlock operates a rail-gap based crowbar system in less than 10µs under any fault condition. Burn patterns are recorded at various stages in the transmission line. The gyrotron is tested for ~200 kW / 1000s operation on a water dummy load. Transmission line is tested at various power levels for long pulse operation. The paper highlights the experimental results of successful commissioning of the system.

  16. Design of 220 GHz electronically scanned reflectarrays for confocal imaging systems

    NASA Astrophysics Data System (ADS)

    Hedden, Abigail S.; Dietlein, Charles R.; Wikner, David A.

    2012-09-01

    The authors analyze properties of a 220 GHz imaging system that uses a scanned reflectarray to perform electronic beam scanning of a confocal imager for applications including imaging meter-sized fields of view at 50 m standoff. Designs incorporating reflectarrays with confocal imagers have not been examined previously at these frequencies. We examine tradeoffs between array size, overall system size, and number of achievable image pixels resulting in a realistic architecture capable of meeting the needs of our application. Impacts to imaging performance are assessed through encircled energy calculations, beam pointing accuracy, and examining the number and intensity of quantization lobes that appear over the scan ranges of interest. Over the desired scan range, arrays with 1 and 2-bit phase quantization showed similar array main beam energy efficiencies. Two-bit phase quantization is advantageous in terms of pointing angle error, resulting in errors of at most 15% of the diffraction-limited beam size. However, both phase quantization cases considered resulted in spurious returns over the scan range of interest and other array layouts should be examined to eliminate potential imaging artifacts.

  17. Development of the 3.7 GHz LHCD system on HL-2A

    NASA Astrophysics Data System (ADS)

    Lu, B.; Huang, M.; Zeng, H.; Bai, X. Y.; Mao, X. H.; Lu, Z. H.; Liang, J.; Kang, Z. H.; Wang, M. W.; Feng, K.; Wang, H.; Wang, C.; Wang, J. Q.; Wei, S.; Yao, T.; Bu, Y. N.; Feng, J.; Cheng, G. Y.; Song, S. D.; Xia, D. H.; Rao, J.

    2014-10-01

    A 2 MW-3.7 GHz lower hybrid current drive (LHCD) system is under development for physics experiments on the HL-2A device. The RF Power is generated by four TH2103A klystron amplifiers and propagates in the TE10 mode through WR284 waveguides. The transmission lines with a length of 20 m to 30 m are pressurized with 2 bars of nitrogen to decrease the possibility of arcing. The launcher, based on the passive-active multi-junction (PAM) concept, has been developed and is currently being realized. It was designed for a power spectrum peaked at N|| = 2.75 with good coupling properties over a wide range of plasma parameters. The four klystrons are fed by a high-voltage power supply (HVPS) based on the pulse step modulation (PSM) concept with a fast switch-off time of less than ten μs. This system is expected to be in operation within 1 years and will explore many international thermonuclear experimental reactor (ITER) related LH experiments in the following years.

  18. 64-GHz millimeter-wave photonic generation with a feasible radio over fiber system

    NASA Astrophysics Data System (ADS)

    Al-Dabbagh, Rasha K.; Al-Raweshidy, Hamed S.

    2017-02-01

    A full-duplex radio over fiber (RoF) link with the generation of a 64-GHz millimeter wave (mm-wave) is investigated. This system is proposed as a solution to cope with the demands of a multi-Gb/s data transmission in the fifth generation (5G) and beyond for small cell networks. Cost reduction and performance improvement are achieved by simplifying the mm-wave generation method with an RoF technique. High-frequency radio signals are considered challenging in the electrical generation domain; therefore, our photonic generation method is introduced and examined. RoF design is proposed for mm-wave generation using both phase modulation and the effect of stimulated Brillouin scattering in the optical fiber for the first time. RoF system with transmission rates of 5 Gb/s is successfully achieved. In our scheme, one laser source is utilized and a fiber Bragg grating is used for wavelength reuse for the uplink connection. Stable mm-wave RoF link is successfully achieved in up to a 100-km fiber link length with high quality carrier. Simulation results show a reduction in fiber nonlinearity effects and the mm-wave signal has low noise equal to -75 dBm. This study ensures a practical mm-wave RoF link, and it could be appropriate for small cell 5G networks by reducing the installation cost.

  19. On the performance of telemedicine system using 17-GHz orthogonally polarized microwave links under the influence of heavy rainfall.

    PubMed

    Fong, Bernard; Fong, A C M; Hong, G Y

    2005-09-01

    This paper describes the design of a telemedicine system based on next-generation wireless local area networks (WLANs) operating at 17 GHz. Seventeen gigahertz is proposed for next-generation WLAN services offering numerous advantages over traditional IEEE 802.11 networks that operate in the range of 2.4-5 GHz. Orthogonal polarization is often used to increase spectrum efficiency by utilizing signal paths of horizontal and vertical polarization. Radio waves exceeding 10 GHz are particularly vulnerable to signal degradation under the influence of rain which causes an effective reduction in isolation between polarized signal paths. This paper investigates the influence of heavy rain in a tropical region on wide-band microwave signals at 17 GHz using two links provided by a fixed broad-band wireless access system for two-way data exchange between paramedics attending an accident scene and the hospital via microwave equipment installed in the ambulance. We also study the effects of cross polarization and phase rotation due to persistent heavy rainfall in tropical regions.

  20. Tunable Twin Matching Frequency (fm1/fm2) Behavior of Ni1-xZnxFe2O4/NBR Composites over 2-12.4 GHz: A Strategic Material System for Stealth Applications

    NASA Astrophysics Data System (ADS)

    Saini, Lokesh; Patra, Manoj Kumar; Jani, Raj Kumar; Gupta, Goutam Kumar; Dixit, Ambesh; Vadera, Sampat Raj

    2017-03-01

    The gel to carbonate precipitate route has been used for the synthesis of Ni1-xZnxFe2O4 (x = 0, 0.25, 0.5 and 0.75) bulk inverse spinel ferrite powder samples. The optimal zinc (50%) substitution has shown the maximum saturation magnetic moment and resulted into the maximum magnetic loss tangent (tanδm) > -1.2 over the entire 2-10 GHz frequency range with an optimum value ~-1.75 at 6 GHz. Ni0.5Zn0.5Fe2O4- Acrylo-Nitrile Butadiene Rubber (NBR) composite samples are prepared at different weight percentage (wt%) of ferrite loading fractions in rubber for microwave absorption evaluation. The 80 wt% loaded Ni0.5Zn0.5Fe2O4/NBR composite (FMAR80) sample has shown two reflection loss (RL) peaks at 5 and 10 GHz. Interestingly, a single peak at 10 GHz for 3.25 mm thickness, can be scaled down to 5 GHz by increasing the thickness up to 4.6 mm. The onset of such twin matching frequencies in FMAR80 composite sample is attributed to the spin resonance relaxation at ~5 GHz (fm1) and destructive interference at λm/4 matched thickness near ~10 GHz (fm2) in these composite systems. These studies suggest the potential of tuning the twin frequencies in Ni0.5Zn0.5Fe2O4/NBR composite samples for possible microwave absorption applications.

  1. Tunable Twin Matching Frequency (fm1/fm2) Behavior of Ni1−xZnxFe2O4/NBR Composites over 2–12.4 GHz: A Strategic Material System for Stealth Applications

    PubMed Central

    Saini, Lokesh; Patra, Manoj Kumar; Jani, Raj Kumar; Gupta, Goutam Kumar; Dixit, Ambesh; Vadera, Sampat Raj

    2017-01-01

    The gel to carbonate precipitate route has been used for the synthesis of Ni1−xZnxFe2O4 (x = 0, 0.25, 0.5 and 0.75) bulk inverse spinel ferrite powder samples. The optimal zinc (50%) substitution has shown the maximum saturation magnetic moment and resulted into the maximum magnetic loss tangent (tanδm) > −1.2 over the entire 2–10 GHz frequency range with an optimum value ~−1.75 at 6 GHz. Ni0.5Zn0.5Fe2O4- Acrylo-Nitrile Butadiene Rubber (NBR) composite samples are prepared at different weight percentage (wt%) of ferrite loading fractions in rubber for microwave absorption evaluation. The 80 wt% loaded Ni0.5Zn0.5Fe2O4/NBR composite (FMAR80) sample has shown two reflection loss (RL) peaks at 5 and 10 GHz. Interestingly, a single peak at 10 GHz for 3.25 mm thickness, can be scaled down to 5 GHz by increasing the thickness up to 4.6 mm. The onset of such twin matching frequencies in FMAR80 composite sample is attributed to the spin resonance relaxation at ~5 GHz (fm1) and destructive interference at λm/4 matched thickness near ~10 GHz (fm2) in these composite systems. These studies suggest the potential of tuning the twin frequencies in Ni0.5Zn0.5Fe2O4/NBR composite samples for possible microwave absorption applications. PMID:28294151

  2. Tunable Twin Matching Frequency (fm1/fm2) Behavior of Ni1-xZnxFe2O4/NBR Composites over 2-12.4 GHz: A Strategic Material System for Stealth Applications.

    PubMed

    Saini, Lokesh; Patra, Manoj Kumar; Jani, Raj Kumar; Gupta, Goutam Kumar; Dixit, Ambesh; Vadera, Sampat Raj

    2017-03-15

    The gel to carbonate precipitate route has been used for the synthesis of Ni1-xZnxFe2O4 (x = 0, 0.25, 0.5 and 0.75) bulk inverse spinel ferrite powder samples. The optimal zinc (50%) substitution has shown the maximum saturation magnetic moment and resulted into the maximum magnetic loss tangent (tanδm) > -1.2 over the entire 2-10 GHz frequency range with an optimum value ~-1.75 at 6 GHz. Ni0.5Zn0.5Fe2O4- Acrylo-Nitrile Butadiene Rubber (NBR) composite samples are prepared at different weight percentage (wt%) of ferrite loading fractions in rubber for microwave absorption evaluation. The 80 wt% loaded Ni0.5Zn0.5Fe2O4/NBR composite (FMAR80) sample has shown two reflection loss (RL) peaks at 5 and 10 GHz. Interestingly, a single peak at 10 GHz for 3.25 mm thickness, can be scaled down to 5 GHz by increasing the thickness up to 4.6 mm. The onset of such twin matching frequencies in FMAR80 composite sample is attributed to the spin resonance relaxation at ~5 GHz (fm1) and destructive interference at λm/4 matched thickness near ~10 GHz (fm2) in these composite systems. These studies suggest the potential of tuning the twin frequencies in Ni0.5Zn0.5Fe2O4/NBR composite samples for possible microwave absorption applications.

  3. Compact Modules for Wireless Communication Systems in the E-Band (71-76 GHz)

    NASA Astrophysics Data System (ADS)

    Montero-de-Paz, Javier; Oprea, Ion; Rymanov, Vitaly; Babiel, Sebastian; García-Muñoz, Luis Enrique; Lisauskas, Alvydas; Hoefle, Matthias; Jimenez, Álvaro; Cojocari, Oleg; Segovia-Vargas, Daniel; Palandöken, Merih; Tekin, Tolga; Stöhr, Andreas; Carpintero, Guillermo

    2013-04-01

    The millimeter-wave spectrum above 70 GHz provides a cost-effective solution to increase the wireless communications data rates by increasing the carrier wave frequencies. We report on the development of two key components of a wireless transmission system, a high-speed photodiode (HS-PD) and a Schottky Barrier Diode (SBD). Both components operate uncooled, a key issue in the development of compact modules. On the transmitter side, an improved design of the HS-PD allows it to deliver an output RF power exceeding 0 dBm (1 mW). On the receiver side, we present the design process and achieved results on the development of a compact direct envelope detection receiver based on a quasi-optical SDB module. Different resonant (meander dipole) and broadband (Log-Spiral and Log-Periodic) planar antenna solutions are designed, matching the antenna and Schottky diode impedances at high frequency. Impedance matching at baseband is also provided by means of an impedance transition to a 50 Ohm output. From this comparison, we demonstrate the excellent performance of the broadband antennas over the entire E-band by setting up a short-range wireless link transmitting a 1 Gbps data signal.

  4. A new exposure system for the in vitro detection of GHz field effects on neuronal networks.

    PubMed

    Koester, Philipp; Sakowski, Jan; Baumann, Werner; Glock, Hans-Walter; Gimsa, Jan

    2007-01-01

    The possible effects of high-frequency electromagnetic fields (EMF) on biological systems are a subject of public concern and scientific discussion. It is generally accepted that the absorption of part of the field energy may cause a temperature rise in biological tissue. Nevertheless, our setup aims to detect possible athermal effects on the electric activity of neuronal in vitro networks. Such networks were formed by primary neurons derived from the murine frontal cortex and cultivated on micro-sensor chips. The action potentials of the neurons were detected in real time by an integrated, electrically passive microelectrode array. For EMF exposure, the chips were introduced into a rectangular wave-guide that could be operated in the propagating or standing wave modes. The drive signals were either continuous waves (1.9-2.2 GHz) or a generic mobile phone signal (UMTS-standard) of up to approximately 8 W. An on-chip sensor allowed the temperature progression to be recorded. In addition, ISFETs and Clark-like electrodes were integrated for the on-chip detection of pH and O(2), respectively.

  5. DPAL pump system exceeding 3kW at 766nm and 30 GHz bandwidth

    NASA Astrophysics Data System (ADS)

    Koenning, Tobias; McCormick, Dan; Irwin, David; Stapleton, Dean; Guiney, Tina; Patterson, Steve

    2016-03-01

    Due to their low quantum defect, diode pumped alkali metal vapor lasers (DPALs) offer the promise of scalability to very high average power levels while maintaining excellent beam quality. Research on DPALs has progressed to ever increasing power levels across multiple gain media species over the last years, necessitating pump power in the kW range. Each material requires a specific pump wavelength: near 852nm for cesium, 780nm for rubidium, 766nm for potassium, and 670nm for lithium atoms. The shorter pump wavelength below 800nm are outside the typical wavelength range for pump diodes developed for diode pumped solid state lasers (DPSS). The biggest challenge in pumping these materials efficiently is the need for maintaining the narrow gain media absorption band of approximately 0.01nm while greatly increasing power. Typical high power diode lasers achieve spectral widths around 3nm (FWHM) in the near infrared spectrum, but optical gratings may be used internal or external to the cavity to reduce the spectral width. Recently, experimental results have shown yet narrower line widths ranging from picometers at very low power levels to sub-100 picometers for water cooled stacks around 1kW of output power. The focus of this work is the development of a fiber-based pump system for potassium DPAL. The individual tasks are the development of high power 766nm chip material, a fiber-coupled module as a building block, and a scalable system design to address power requirements from hundreds of watts to tens of kilowatts. Results for a 3kW system achieving ~30GHz bandwidth at 766nm will be shown. Approaches for power-scaling and size reduction will be discussed.

  6. High Resolution GHZ and Thz (ftir) Spectroscopy and Theory of Parity Violation and Tunneling for 1,2-DITHIINE (C4H4S2) as a Candidate for Measuring the Parity Violating Energy Difference Between Enantiomers of Chiral Molecules

    NASA Astrophysics Data System (ADS)

    Albert, Sieghard; Bolotova, Irina; Chen, Ziqiu; Fábri, Csaba; Horny, Lubos; Quack, Martin; Seyfang, Georg; Zindel, Daniel

    2016-06-01

    We report high resolution spectroscopic results for 1,2-dithiine-(1,2-dithia-3,5-cyclohexadiene,C4H4S2) in the Gigahertz and Terahertz spectroscopic ranges and exploratory theoretical calculations of parity violation and tunneling processes in view of a possible experimental determination of the parity violating energy difference ΔpvE in this chiral molecule. Theory predicts that the parity violating energy difference in the ground state (ΔpvE≃11x10-11(hc) wn)is in principle measurable as it is much larger than the calculated tunneling splitting for the symmetrical potential Δ±E≃10-24(hc) wn. With a planar transition state for stereomutation at about 2500 wn tunneling splittings become appreciable above 2300 wn. This makes levels of well defined parity accessible to parity selection by available powerful infrared lasers and thus useful for one of the existing experimental approaches towards molecular parity violation. The new GHz spectra lead to greatly improved ground state rotational parameters for 1,2-dithiine. These are used as starting point for the first successful analyses of high resolution interferometric Fourier Transform Infrared (FTIR, THz) spectra for the fundamentals ν17 (1308.873 wn or 39.23903 THz), ν22 (623.094 wn or 18.67989 THz) and ν3 (1544.900 wn or 46.314937 THz) for which highly accurate spectroscopic parameters are reported. The results are discussed in relation to current efforts to measure ΔpvE.a-. M. Quack , Fundamental Symmetries and Symmetry Violations from High-resolution Spectroscopy, Handbook of High Resolution Spectroscopy, M. Quack and F. Merkt eds.,John Wiley & Sons Ltd, Chichester, New York, 2001, vol. 1, ch. 18, pp. 659-722 S. Albert, I. Bolotova, Z. Chen, C. Fábri, L. Horny, M. Quack, G. Seyfang and D. Zindel,Proceedings of the 20th Symposium on Atomic, Cluster and Surface Physics (SASP 2016), Innsbruck University Press, 2016, pp. 127-130, ISBN:978-3-903122-04-8. and to be published P. Dietiker, E. Miloglyadov, M

  7. Use of the 30/20 GHz band by multipurpose satellite systems

    NASA Technical Reports Server (NTRS)

    Mcneil, Stephen; Mimis, Vassilios; Sahay, Vishnu; Bowen, Robert

    1993-01-01

    The World Administrative Radio Conference (WARC) held in 1992 allocated the bands 19.7-20.2 GHz and 29.5-30.0 GHz to both the Mobile Satellite Service (MSS) and the Fixed Satellite Service (FSS) on a co-primary basis. An economic and flexible solution for the provision of both services is to place both payloads on one spacecraft. Some of the proposed applications of such a hybrid satellite network are described. It also examines the facility for spectrum sharing between the various applications and discusses the impact on coordination. It is concluded that the coordination process would not be more onerous than traditional FSS inter-satellite coordination.

  8. Controlled Quantum Teleportation via the GHZ Entangled Ions in the Ion-Trapped System

    NASA Astrophysics Data System (ADS)

    Xu, Xiong; Wang, Xiaoxue

    2016-08-01

    In this paper, we present a controlled quantum teleportation protocol. In the protocol, quantum information of an unknown state is faithfully transmitted from a sender (Alice) to a remote receiver (Bob) via the GHZ entangled ions under the control of the supervisor Charlie. The apparent Bell-state measurements that Alice should perform in order to teleport her ions are not needed.

  9. 77 FR 48097 - Operation of Radar Systems in the 76-77 GHz Band

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-13

    ... general public. 3. The 76-77 GHz band, which is allocated to the Radio Astronomy service (RAS) and the... interference to RAS operations. Because the radio astronomy observatories typically have control over access to... jointly by representatives from the radio astronomy community and several vehicular radar...

  10. Violation of local realism by a system with N spin-(1/2) particles

    SciTech Connect

    Wu, Xiao-Hua; Zong, Hong-Shi

    2003-09-01

    Recently, it was found that Mermin's inequalities may not always be optimal for the refutation of a local realistic description [Phys. Rev. Lett. 88, 210402 (2002)]. To complete this work, we derive an inequality for the Greenberger-Horne-Zeilinger-type pure state for a system with N spin-(1/2) particles and the violation of the inequality can be shown for all the non product pure states. Mermin's inequality for a system of N spin-(1/2) particles and Gisin's theorem for a system of two spin-(1/2) particles are both included in our inequality.

  11. Bidirectional 60-GHz radio-over-fiber systems with downstream OFDMA and wavelength reuse upstream SC-FDMA.

    PubMed

    Zhang, Cheng; Duan, Jun; Li, Juhao; Hu, Weiwei; Li, Hongbin; Wu, Hequan; Chen, Zhangyuan

    2010-08-30

    We have proposed and experimentally demonstrated a 60-GHz bidirectional radio-over-fiber system with downstream orthogonal frequency division multiplexing address (OFDMA) and wavelength reuse upstream single-carrier frequency division multiple address (SC-FDMA). In the downstream, a 3-dB optical coupler is used for two-carrier injection-locking a distributed feedback (DFB) laser in order to realize the single-sideband modulation. In the upstream, the weakly modulated one of the two downstream carriers is filtered out for wavelength reuse. Transmission of 9.65-Gb/s 16-QAM downstream OFDMA on 60-GHz carrier and 5-Gb/s QPSK upstream SC-FDMA (2.5 Gb/s for each user) are both successfully demonstrated over 53-km standard single mode fiber without chromatic dispersion compensation. The crosstalk between the downstream OFDMA and the upstream SC-FDMA can be neglected.

  12. Design and RF measurements of a 5 GHz 500 kW window for the ITER LHCD system

    NASA Astrophysics Data System (ADS)

    Hillairet, J.; Achard, J.; Bae, Y. S.; Bernard, J. M.; Dechambre, N.; Delpech, L.; Ekedahl, A.; Faure, N.; Goniche, M.; Kim, J.; Larroque, S.; Magne, R.; Marfisi, L.; Namkung, W.; Park, H.; Park, S.; Poli, S.; Vulliez, K.

    2014-02-01

    CEA/IRFM is conducting R&D efforts in order to validate the critical RF components of the 5 GHz ITER LHCD system, which is expected to transmit 20 MW of RF power to the plasma. Two 5 GHz 500 kW BeO pill-box type window prototypes have been manufactured in 2012 by the PMB Company, in close collaboration with CEA/IRFM. Both windows have been validated at low power, showing good agreement between measured and modeling, with a return loss better than 32 dB and an insertion loss below 0.05 dB. This paper reports on the window RF design and the low power measurements. The high power tests up to 500kW have been carried out in March 2013 in collaboration with NFRI. Results of these tests are also reported.

  13. Synthesis of the new ring system bispyrido[4',3':4,5]pyrrolo [1,2-a:1',2'-d]pyrazine and its deaza analogue.

    PubMed

    Parrino, Barbara; Spanò, Virginia; Carbone, Anna; Barraja, Paola; Diana, Patrizia; Cirrincione, Girolamo; Montalbano, Alessandra

    2014-08-29

    Derivatives of the new ring systems bispyrido[4',3':4,5]pyrrolo[1,2-a:1',2'-d] pyrazine-6,13-dione and its deaza analogue pyrido[4'',3'':4',5']pyrrolo-[1',2':4,5]pyrazino [1,2-a]indole-6,13-dione were conveniently synthesized through a four-step sequence. Symmetrical derivatives of the former ring system were obtained through self condensation. On the other hand, condensation of 6-azaindole carboxylic acid with indole 2-carboxylic acid afforded the deaza analogue ring system. Derivatives of the title ring system were tested by the National Cancer Institute (Bethesda, MD, USA) and four of them exhibited modest activity against MCF7 (a breast cancer cell line) and/or UO-31 (a renal cancer cell line).

  14. Conceptual communications system design in the 25.25-27.5 and 37.0-40.5 GHz frequency bands

    NASA Technical Reports Server (NTRS)

    Thompson, Michael W.

    1993-01-01

    Future space applications are likely to rely heavily on Ka-band frequencies (20-40 GHz) for communications traffic. Many space research activities are now conducted using S-band and X-band frequencies, which are becoming congested and require a degree of pre-coordination. In addition to providing relief from frequency congestion, Ka-band technologies offer potential size, weight, and power savings when compared to lower frequency bands. The use of the 37.0-37.5 and 40.0-40.5 GHz bands for future planetary missions was recently approved at the 1992 World Administrative Radio Conference (WARC-92). WARC-92 also allocated the band 25.25-27.5 GHz to the Intersatellite Service on a primary basis to accommodate Data Relay Satellite return link requirements. Intersatellite links are defined to be between artificial satellites and thus a communication link with the surface of a planetary body, such as the moon, and a relay satellite orbiting that body are not permitted in this frequency band. This report provides information about preliminary communications system concepts for forward and return links for earth-Mars and earth-lunar links using the 37.0-37.5 (return link) and 40.0-40.5 (forward link) GHz frequency bands. In this study we concentrate primarily on a conceptual system for communications between earth and a single lunar surface terminal (LST), and between earth and a single Mars surface terminal (MST). Due to large space losses, these links have the most stringent link requirements for an overall interplanetary system. The earth ground station is assumed to be the Deep Space Network (DSN) using either 34 meter or 70 meter antennas. We also develop preliminary communications concepts for a space-to-space system operating at near 26 GHz. Space-to-space applications can encompass a variety of operating conditions, and we consider several 'typical' scenarios described in more detail later in this report. Among these scenarios are vehicle-to-vehicle communications

  15. Absence of exponential sensitivity to small perturbations in nonintegrable systems of spins 1/2

    NASA Astrophysics Data System (ADS)

    Fine, B. V.; Elsayed, T. A.; Kropf, C. M.; de Wijn, A. S.

    2014-01-01

    We show that macroscopic nonintegrable lattices of spins 1/2, which are often considered to be chaotic, do not exhibit the basic property of classical chaotic systems, namely, exponential sensitivity to small perturbations. We compare chaotic lattices of classical spins and nonintegrable lattices of spins 1/2 in terms of their magnetization responses to an imperfect reversal of spin dynamics known as Loschmidt echo. In the classical case, magnetization is exponentially sensitive to small perturbations with a characteristic exponent equal to twice the value of the largest Lyapunov exponent of the system. In the case of spins 1/2, magnetization is only power-law sensitive to small perturbations.

  16. Comparative study of FDMA, TDMA and hybrid 30/20 GHz satellite communications systems for small users

    NASA Technical Reports Server (NTRS)

    Berk, G.; Jean, P. N.; Rotholz, E.

    1982-01-01

    This study compares several satellite uplink and downlink accessing schemes for a Customer Premises Service. Four conceptual system designs are presented: Satellite-Routed FDMA, Frequency-Routed TDMA, Satellite-Switched TDMA, and Processor-Routed TDMA, operating in the 30/20 GHz band. The designs are compared on the basis of estimated satellite weight, power consumption, and cost. The system capacities are analyzed for a fixed multibeam coverage of CONUS. Analysis shows that the system capacity is limited by the available satellite resources and by the terminal size and cost.

  17. RF Behavior of Cylindrical Cavity Based 240 GHz, 1 MW Gyrotron for Future Tokamak System

    NASA Astrophysics Data System (ADS)

    Kumar, Nitin; Singh, Udaybir; Bera, Anirban; Sinha, A. K.

    2017-07-01

    In this paper, we present the RF behavior of conventional cylindrical interaction cavity for 240 GHz, 1 MW gyrotron for futuristic plasma fusion reactors. Very high-order TE mode is searched for this gyrotron to minimize the Ohmic wall loading at the interaction cavity. The mode selection process is carried out rigorously to analyze the mode competition and design feasibility. The cold cavity analysis and beam-wave interaction computation are carried out to finalize the cavity design. The detail parametric analyses for interaction cavity are performed in terms of mode stability, interaction efficiency and frequency. In addition, the design of triode type magnetron injection gun is also discussed. The electron beam parameters such as velocity ratio and velocity spread are optimized as per the requirement at interaction cavity. The design studies presented here confirm the realization of CW, 1 MW power at 240 GHz frequency at TE46,17 mode.

  18. 14 CFR Sec. 1-2 - Waivers from this system of accounts and reports.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED AIR CARRIERS General Accounting Provisions Sec. 1-2 Waivers from this system of accounts and reports... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Waivers from this system of accounts and...

  19. 14 CFR Sec. 1-2 - Waivers from this system of accounts and reports.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS UNIFORM SYSTEM OF ACCOUNTS AND REPORTS FOR LARGE CERTIFICATED AIR CARRIERS General Accounting Provisions Sec. 1-2 Waivers from this system of accounts and reports... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Waivers from this system of accounts and...

  20. Developments of 60 ghz antenna and wireless interconnect inside multi-chip module for parallel processor system

    NASA Astrophysics Data System (ADS)

    Yeh, Ho-Hsin

    In order to carry out the complicated computation inside the high performance computing (HPC) systems, tens to hundreds of parallel processor chips and physical wires are required to be integrated inside the multi-chip package module (MCM). The physical wires considered as the electrical interconnects between the processor chips, however, have the challenges on placements and routings because of the unequal progress between the semiconductor and I/O size reductions. The primary goal of the research is to overcome package design challenges---providing a hybrid computing architecture with implemented 60 GHz antennas as the high efficient wireless interconnect which could generate over 10 Gbps bandwidth on the data transmissions. The dissertation is divided into three major parts. In the first part, two different performance metrics, power loss required to be recovered ( PRE) and wireless link budget, on evaluating the antenna's system performance within the chip to chip wireless interconnect are introduced to address the design challenges and define the design goals. The second part contains the design concept, fabrication procedure and measurements of implemented 60 GHz broadband antenna in the application of multi-chip data transmissions. The developed antenna utilizes the periodically-patched artificial magnetic conductor (AMC) structure associated with the ground-shielded conductor in order to enhance the antenna's impedance matching bandwidth. The validation presents that over 10 GHz -10 dB S11 bandwidth which indicates the antenna's operating bandwidth and the horizontal data transmission capability which is required by planar type chip to chip interconnect can be achieved with the design concept. In order to reduce both PRE and wireless link budget numbers, a 60 GHz two-element array in the multi-chip communication is developed in the third part. The third section includes the combined-field analysis, the design concepts on two-element array and feeding

  1. Phenotyping of Nod1/2 double deficient mice and characterization of Nod1/2 in systemic inflammation and associated renal disease.

    PubMed

    Stroo, Ingrid; Butter, Loes M; Claessen, Nike; Teske, Gwen J; Rubino, Stephen J; Girardin, Stephen E; Florquin, Sandrine; Leemans, Jaklien C

    2012-12-15

    It is indispensable to thoroughly characterize each animal model in order to distinguish between primary and secondary effects of genetic changes. The present study analyzed Nod1 and Nod2 double deficient (Nod1/2 DKO) mice under physiological and inflammatory conditions. Nod1 and Nod2 are members of the Nucleotide-binding domain and Leucine-rich repeat containing Receptor (NLR) family. Several inflammatory disorders, such as Crohn's disease and asthma, are linked to genetic changes in either Nod1 or Nod2. These associations suggest that Nod1 and Nod2 play important roles in regulating the immune system.Three-month-old wildtype (Wt) and Nod1/2 DKO mice were sacrificed, body and organ weight were determined, and blood was drawn. Except for lower liver weight in Nod1/2 DKO mice, no differences were found in body/organ weight between both strains. Leukocyte count and composition was comparable. No significant changes in analyzed plasma biochemical markers were found. Additionally, intestinal and vascular permeability was determined. Nod1/2 DKO mice show increased susceptibility for intestinal permeability while vascular permeability was not affected. Next we induced septic shock and organ damage by administering LPS+PGN intraperitoneally to Wt and Nod1/2 DKO mice and sacrificed animals after 2 and 24 hours. The systemic inflammatory and metabolic response was comparable between both strains. However, renal response was different as indicated by partly preserved kidney function and tubular epithelial cell damage in Nod1/2 DKO at 24 hours. Remarkably, renal inflammatory mediators Tnfα, KC and Il-10 were significantly increased in Nod1/2 DKO compared with Wt mice at 2 hours.Systematic analysis of Nod1/2 DKO mice revealed a possible role of Nod1/2 in the development of renal disease during systemic inflammation.

  2. Safety of a preservative system containing 1,2-hexanediol and caprylyl glycol.

    PubMed

    Levy, Stanley B; Dulichan, Anthony M; Helman, Michael

    2009-01-01

    To study the potential for delayed Type IV dermal sensitivity of a new preservative system containing 1,2-hexanediol and caprylyl glycol, 200-subject repeat insult patch tests were performed with a 15% mixture of 1,2-hexanediol and caprylyl glycol (equal parts of the 2 ingredients) in carbomer gel and a cosmetic formulation at an actual use concentration. No delayed Type IV hypersensitivity reactions were observed.

  3. Analysis of surface error correction capability of 1.2m active support system

    NASA Astrophysics Data System (ADS)

    Han, Yu; Fan, Bin; Li, Chaoqiang; Liu, Haitao

    2016-10-01

    The surface error correction ability is one of the important indicators to measure the performance of the active support system. In this paper, the correction force algorithm for the active support system of 1.2m thin meniscus mirror is introduced. Based on this algorithm, a simulation analysis is made. The simulation results show that the 1.2m active support system has excellent correction ability for Zernike polynomials term 4, 5, 6, 10 and 11, and has a good effect on the Zernike polynomials term 7 and 8.

  4. Determining potential 30/20 GHz domestic satellite system concepts and establishment of a suitable experimental configuration

    NASA Technical Reports Server (NTRS)

    Stevens, G. H.; Anzic, G.

    1979-01-01

    Issues and results in a NASA study of the potential concepts and markets for a multibeam 30/20 GHz domestic satellite system in the 1990s are presented. Issues considered include the reduction of signal attenuation due to rain, beam-beam interference isolation in the multibeam system, the method of access/modulation (FDMA, TDMA or hybrid) and the market for reduced reliability and wideband services. A hypothetical demonstration payload configuration which would attempt to resolve these issues is illustrated. The communications payload would employ a system of seven contiguous coverage spots in order to demonstrate a typical cell in a contiguous beam system having extensive frequency re-use, as in a direct-to-user system, and a single spot, typical of a trunking system, to determine signal isolation. The payload could be carried on several existing buses and is illustrated on an MMS bus.

  5. Determining potential 30/20 GHZ domestic satellite system concepts and establishment of a suitable experimental configuration

    NASA Technical Reports Server (NTRS)

    Stevens, G. H.; Anzic, G.

    1979-01-01

    NASA is conducting a series of millimeter wave satellite communication systems and market studies to: (1) determine potential domestic 30/20 GHz satellite concepts and market potential, and (2) establish the requirements for a suitable technology verification payload which, although intended to be modest in capacity, would sufficiently demonstrate key technologies and experimentally address key operational issues. Preliminary results and critical issues of the current contracted effort are described. Also included is a description of a NASA-developed multibeam satellite payload configuration which may be representative of concepts utilized in a technology flight verification program.

  6. Design, analysis, and transmission system performance of a 41 GHz silicon photonic modulator.

    PubMed

    Patel, David; Ghosh, Samir; Chagnon, Mathieu; Samani, Alireza; Veerasubramanian, Venkat; Osman, Mohamed; Plant, David V

    2015-06-01

    The design and characterization of a slow-wave series push-pull traveling wave silicon photonic modulator is presented. At 2 V and 4 V reverse bias, the measured -3 dB electro-optic bandwidth of the modulator with an active length of 4 mm are 38 GHz and 41 GHz, respectively. Open eye diagrams are observed up to bitrates of 60 Gbps without any form of signal processing, and up to 70 Gbps with passive signal processing to compensate for the test equipment. With the use of multi-level amplitude modulation formats and digital-signal-processing, the modulator is shown to operate below a hard-decision forward error-correction threshold of 3.8×10-3 at bitrates up to 112 Gbps over 2 km of single mode optical fiber using PAM-4, and over 5 km of optical fiber with PAM-8. Energy consumed solely by the modulator is also estimated for different modulation cases.

  7. A feasibility study on image-based control of surgical robot using a 60-GHz wireless communication system.

    PubMed

    Takizawa, Kenichi; Omori, Shigeru; Harada, Hideo; Nakamura, Ryoichi; Muragaki, Yoshihiro; Iseki, Hiroshi

    2009-01-01

    This paper presents an evaluation study on the feasibility of introducing wireless connection into a neurosurgical robot, which is controlled by an image-based navigation system. The wireless connection introduced into the robotic system is based on amplitude shift keying (ASK) at 60 GHz. With this wireless connection, data transmission at the bit-rate of 1 Gbps or more is possible, and here high-definition video images (1080i/1080p) can be transmitted. Such a wireless connection system is implemented in the surgical robot replaces the cable connection between the digital video camera and the controller. In this study, the wireless robotic surgical system is evaluated in terms of its accuracy of navigation using the transmitted video images. The results of a wireless connection test under a line-of-sight (LOS) environment show that navigation accuracy observed when using this wireless surgical robot is comparable to that when using a wired robotic system.

  8. Estimation of Transmitting Power to Compensate for Rain Attenuation for a Broadcasting Satellite System in the 21-GHz Band

    NASA Astrophysics Data System (ADS)

    Minematsu, Fumiaki; Tanaka, Shoji; Nakagawa, Hitoshi; Kawaguchi, Yutaka

    2002-01-01

    1. INTRODUCTION Rain attenuation in the 21-GHz band is much larger than that in the conventionally used 12-GHz band and the rain attenuation causes more serious program interruptions compared with that in the 12-GHz band. We are now studying an advanced broadcasting satellite in the 21-GHz band that enables adaptive compensation for heavy rain area by boosted beams using an on-board phased-array-transmitting antenna. To know the scale of this satellite system, it is important to estimate transmitting power needed to compensate for rain attenuation. Rain attenuation has so close association with rainfall that it is possible to estimate rain attenuation by measured rainfall. Japan meteorological agency is measuring 1-hour rainfalls for about 1300 locations in Japan. In this study, 1-hour rainfall data accumulated at more than 1000 locations over a period of 20 years were used statistically to grasp rainfall distribution throughout Japan and the transmitting power for compensation was estimated by use of these data. 2. CALCULATION MODEL FOR TRANSMITTING POWER ESTIMATION Assumed rain attenuation compensation area for Japanese archipelago was divided into 112 square areas. A size of each square was 0.1 degree in terms of azimuth and elevation angle for the beam direction of satellite transmitting antenna. For calculation, the link margin of 3.5 dB for clear sky was given to the area where 1-hour rainfall not larger than 3 mm was detected. For other square areas where 1-hour rainfall larger than 3 mm was detected, the link margin of 12 dB was given. The former link margin corresponds to the service availability of 99 % and the latter does to that of 99.9 % in an average year in Tokyo. A total system efficiency included radiation efficiency of the transmitting antenna of 1.0 was assumed. As modulation scheme, trellis coded 8-PSK (TC8PSK) was assumed. The required reception CN ratio for TC8PSK is 10.7 dB. As to TC8PSK, the baud rate of 57.72 Mbaud gives more than 100 Mbps

  9. [National system of protection against electromagnetic fields 0 Hz-300 GHz in the light of current legal regulations].

    PubMed

    Aniołczyk, Halina

    2006-01-01

    Exposure to electromagnetic fields (EMF) occurs when man is exposed to the effect of electric, magnetic and electromagnetic fields and contact currents different from those resulting from physiological processes in the organism or other natural phenomena. In Poland, the system of protection against EMF has been functioning for over 35 years. In 2001, when the Minister of Labor and Social Policy issued the regulation introducing the maximum admissible intensities (MAI) for electromagnetic fields and radiation within the range of 0 Hz-300 GHz, the system was directed mainly towards evaluation of exposure to EMF occurring in the occupational environment. The system is linked via MAI values with human protection in the natural environment. In this paper, the background, principles and the range of the national system of protection against EMF and its monitoring are presented. The project of implementation of EU directives, following Poland's accession to the European Union is also discussed.

  10. Multi-megawatt 110 GHz ECH system for the DIII-D tokamak

    SciTech Connect

    Callis, R.W.; Lohr, J.; O`Neill, R.C.; Ponce, D.; Prater, R.

    1997-11-01

    Two 110 GHz gyrotrons with nominal output power of 1 MW each have been installed on the DIII-D tokamak. The first 110 GHz gyrotron built by Gycom has a nominal rating of 1 MW and a 2s pulse length, with the pulse length being determined by the maximum temperature allowed on the edge cooled boron nitride window. This gyrotron was first operated into the DIII-D tokamak in late 1996. The second gyrotron was built by Communications and Power Industries (CPI) was commissioned during the spring of 1997. The CPI gyrotron uses a double disc FC-75 cooled sapphire window which has a pulse length rating of 0.8s at 1 MW, 2s at 0.5 MW and 10s at 0.2 MW. Both gyrotrons are connected to the tokamak by a low-loss-windowless evacuated transmission line using circular corrugated waveguide for propagation in the HE(11) mode. Using short pulse lengths to avoid breakdown inside the air filled waveguide, the microwave beam has been measured inside the DIII-D vacuum vessel using a paper target and an IR camera. The resultant microwave beam was found to be well focused with a spot size of approximately 8 cm. The beam can be steered poloidially from the center to the outer edge of the plasma. The initial operation of the Gycom gyrotron with about 0.5 MW delivered to a low density plasma for 0.5 s showed good central electron heating, with peak temperature in excess of 10 keV. A third gyrotron, being built by CPI, will be installed later this year. Progress with the first CPI tube will also be discussed and future plans for the ECH installation and physics experiments will be presented.

  11. Sensing glucose concentrations at GHz frequencies with a fully embedded Biomicro-electromechanical system (BioMEMS).

    PubMed

    Birkholz, M; Ehwald, K-E; Basmer, T; Kulse, P; Reich, C; Drews, J; Genschow, D; Haak, U; Marschmeyer, S; Matthus, E; Schulz, K; Wolansky, D; Winkler, W; Guschauski, T; Ehwald, R

    2013-06-28

    The progressive scaling in semiconductor technology allows for advanced miniaturization of intelligent systems like implantable biosensors for low-molecular weight analytes. A most relevant application would be the monitoring of glucose in diabetic patients, since no commercial solution is available yet for the continuous and drift-free monitoring of blood sugar levels. We report on a biosensor chip that operates via the binding competition of glucose and dextran to concanavalin A. The sensor is prepared as a fully embedded micro-electromechanical system and operates at GHz frequencies. Glucose concentrations derive from the assay viscosity as determined by the deflection of a 50 nm TiN actuator beam excited by quasi-electrostatic attraction. The GHz detection scheme does not rely on the resonant oscillation of the actuator and safely operates in fluidic environments. This property favorably combines with additional characteristics-(i) measurement times of less than a second, (ii) usage of biocompatible TiN for bio-milieu exposed parts, and (iii) small volume of less than 1 mm(3)-to qualify the sensor chip as key component in a continuous glucose monitor for the interstitial tissue.

  12. Sensing glucose concentrations at GHz frequencies with a fully embedded Biomicro-electromechanical system (BioMEMS)

    NASA Astrophysics Data System (ADS)

    Birkholz, M.; Ehwald, K.-E.; Basmer, T.; Kulse, P.; Reich, C.; Drews, J.; Genschow, D.; Haak, U.; Marschmeyer, S.; Matthus, E.; Schulz, K.; Wolansky, D.; Winkler, W.; Guschauski, T.; Ehwald, R.

    2013-06-01

    The progressive scaling in semiconductor technology allows for advanced miniaturization of intelligent systems like implantable biosensors for low-molecular weight analytes. A most relevant application would be the monitoring of glucose in diabetic patients, since no commercial solution is available yet for the continuous and drift-free monitoring of blood sugar levels. We report on a biosensor chip that operates via the binding competition of glucose and dextran to concanavalin A. The sensor is prepared as a fully embedded micro-electromechanical system and operates at GHz frequencies. Glucose concentrations derive from the assay viscosity as determined by the deflection of a 50 nm TiN actuator beam excited by quasi-electrostatic attraction. The GHz detection scheme does not rely on the resonant oscillation of the actuator and safely operates in fluidic environments. This property favorably combines with additional characteristics—(i) measurement times of less than a second, (ii) usage of biocompatible TiN for bio-milieu exposed parts, and (iii) small volume of less than 1 mm3—to qualify the sensor chip as key component in a continuous glucose monitor for the interstitial tissue.

  13. Product operator theory for IS (I=1/2 S=3/2) spin system

    NASA Astrophysics Data System (ADS)

    Dasgin, Hacer; Saka, Irfan

    2017-02-01

    In Nuclear Magnetic Resonance (NMR) experiments for weakly coupled spin system, product operator theory is widely used for analytical descriptions and experimental suggestions. Interaction with weakly coupled of IS (I=3/2, S=1/2) spin systems have 64 product operators. Changing of these operators named as evolution and 12 of these evolutions under the spin-spin coupling Hamiltonian of product operators were derived in this study.

  14. Propagation effects on satellite systems at frequencies below 10 GHz, a handbook for satellite systems design, 1st edition

    NASA Technical Reports Server (NTRS)

    Flock, W. L.

    1983-01-01

    Satellite communications below about 6 GHz may need to contend with ionospheric effects, including Faraday rotation and ionospheric scintillation, which become increasingly significant with decreasing frequency. Scintillation is most serious in equatorial, auroral, and polar latitudes; even the 4 to 6 GHz frequency range turns out to be subject to scintillation to a significant degree of equatorial latitudes. Faraday rotation, excess range or time delay, phase advance, Doppler frequency fluctuations, and dispersion are proportional to total electron content (TEC) or its variation along the path. Tropospheric refraction and fading affects low angle satellite transmissions as well as terrestrial paths. Attenuation and depolarization due to rain become less important with decreasing frequency but need consideration for frequencies of about 4 GHz and higher. Empirically derived relations are useful for estimating the attenuation expected due to rain for particular percentages of time. Aeronautical, maritime, and land mobile satellite services are subject to fading due to multipath propagation.

  15. Digital predistortion of 75-110 GHz W-band frequency multiplier for fiber wireless short range access systems.

    PubMed

    Zhao, Ying; Deng, Lei; Pang, Xiaodan; Yu, Xianbin; Zheng, Xiaoping; Zhang, Hanyi; Monroy, Idelfonso Tafur

    2011-12-12

    We present a W-band fiber-wireless transmission system based on a nonlinear frequency multiplier for high-speed wireless short range access applications. By implementing a baseband digital signal predistortion scheme, intensive nonlinear distortions induced in a sextuple frequency multiplier can be effectively pre-compensated. Without using costly W-band components, a transmission system with 26 km fiber and 4 m wireless transmission operating at 99.6 GHz is experimentally validated. Adjacent-channel power ratio (ACPR) improvements for IQ-modulated vector signals are guaranteed and transmission performances for fiber and wireless channels are studied. This W-band predistortion technique is a promising candidate for applications in high capacity wireless-fiber access systems.

  16. High power system for ECRH at 140Ghz, 2MW, 0.5s on FTU tokamak

    SciTech Connect

    Sozzi, C.; Bozzi, R.; Bruschi, A.; Cirant, S.; Gandini, F.; Granucci, G.; Mellera, V.; Muzzini, V.; Nardone, A.; Simonetto, A.; Spinicchia, N.; Berardi, B.; Ciccone, G.; DiGiovenale, S.; Iannone, F.; Lupini, S.; Mantovani, S.; Pesci, E.

    1999-09-20

    The 140GHz, 2MW, 0.5s ECRH system on FTU tokamak integrates closed waveguide transmission lines ({approx_equal}30 m) with quasi optical systems at both ends for efficient coupling from the 4 gyrotrons to the 4 waveguides and from these to the plasma through a single access port. Poloidal and toroidal control of the beam's launching angles and polarization is performed without movable components close to the plasma. Most of the components of each generation and transmission system were designed to operate at a power level higher than 0.5 MW, and a possible up-grade to a full 1 MW, 0.5 s capability is discussed.

  17. Integrated 222-GHz corner-reflector antennas

    NASA Astrophysics Data System (ADS)

    Gearhart, Steven S.; Ling, Curtis C.; Rebeiz, Gabriel M.

    1991-01-01

    A high-gain monolithic millimeter-wave antenna has been designed, fabricated, and tested at 222 GHz. The structure consists of a traveling-wave antenna integrated on a 1.2-micron dielectric membrane and suspended in a longitudinal cavity etched in a silicon wafer. A new traveling-wave antenna design yields a wideband input impedance and a low cross-polarization component in the E- and quasi-H-plane patterns. A directivity of 17.7 dB and a main-beam efficiency of 88.5 percent are calculated from the 222-GHz pattern measurements. The integrated corner-reflector antenna is well suited for millimeter- and submillimeter-wave imaging applications in large f-number systems.

  18. Robust control system for the new 1.2-m telescopes of the Geneva Observatory

    NASA Astrophysics Data System (ADS)

    Russiniello, Giovanni B.; Huguenin, Daniel; Wildi, Francois P.

    2000-06-01

    This paper presents the distributed hardware and software architecture of this 1.2-meter telescope control system, entirely designed and built by the Geneva Observatory. The modular concept and the choices of hardware tested in industrial automation made it possible to obtain great operational robustness and guarantee for long-term maintenance. The adopted solution is based on a transputer tree-network. The interactions between telescope and observer are transparent and completely integrated in the observation software of the attached instrument.

  19. Student understanding of the time dependence of spin-1/2 systems

    NASA Astrophysics Data System (ADS)

    Passante, Gina

    2016-03-01

    Time dependence is one of the most difficult concepts in quantum mechanics and one that is relevant throughout instruction. In this talk I will explore student responses to written questions regarding the time dependence for spin-1/2 systems after lecture instruction and again after a tutorial on the topic. These questions were asked in a junior-level quantum mechanics course that is taught using a spins-first curriculum.

  20. Test results of 3.7 GHz 500kW CW klystron for SST1 LHCD system

    NASA Astrophysics Data System (ADS)

    Sharma, Promod Kumar; Ambulkar, Kiran K.; Dalakoti, Shefali; Rajan Babu, N.; Parmar, Pramod R.; Virani, Chetan G.; Thakur, Arvind L.

    2012-10-01

    A 3.7 GHz, LHCD system aims to driving non inductive plasma current for SST1 machine. Its capability has been enhanced up to 2 MW by adding two additional klystrons, each rated for 500kW, CW power. The additional klystrons are installed and commissioned at site, for rated power, for more than 1000 seconds, before connecting them to main LHCD system. The auxiliary systems, like supporting power supply system (magnet, filament, ion pump, etc.), active heat management system, slow and fast interlock system, transmission line pressurization system, low power rf drive system, etc. are inter-connected with klystron system through VME based data acquisition and control system for remote CW operation of klystron at rated power. The calorimetric measurements, employing Pt-100 sensors, suggests that the maximum rf power (˜500kW CW) extracted from klystron is dissipated on water cooled dummy loads. The unspent DC power (˜800 kW CW) is dissipated in collector which is heavily cooled with water flowing at ˜1300 litres/min (lpm). The power loss in the klystron body remained within 20 kW. The cavity temperature, measured using J-type thermocouple, remained below 150 ^oC. The output rf power, sampled through directional couplers and measured by rf detectors shows good agreement with calorimetric measurements. A detailed description of the klystron test set up and the test results obtained during its commissioning is presented in this paper.

  1. Construction and (13) C hyperpolarization efficiency of a 180 GHz dissolution dynamic nuclear polarization system.

    PubMed

    Kiswandhi, Andhika; Niedbalski, Peter; Parish, Christopher; Ferguson, Sarah; Taylor, David; McDonald, George; Lumata, Lloyd

    2017-09-01

    Dynamic nuclear polarization (DNP) via the dissolution method has become one of the rapidly emerging techniques to alleviate the low signal sensitivity in nuclear magnetic resonance (NMR) spectroscopy and imaging. In this paper, we report on the development and (13) C hyperpolarization efficiency of a homebuilt DNP system operating at 6.423 T and 1.4 K. The DNP hyperpolarizer system was assembled on a wide-bore superconducting magnet, equipped with a standard continuous-flow cryostat, and a 180 GHz microwave source with 120 mW power output and wide 4 GHz frequency tuning range. At 6.423 T and 1.4 K, solid-state (13) C polarization P levels of 64% and 31% were achieved for 3 M [1-(13) C] sodium acetate samples in 1 : 1 v/v glycerol:water glassing matrix doped with 15 mM trityl OX063 and 40 mM 4-oxo-TEMPO, respectively. Upon dissolution, which takes about 15 s to complete, liquid-state (13) C NMR signal enhancements as high as 240 000-fold (P=21%) were recorded in a nearby high resolution (13) C NMR spectrometer at 1 T and 297 K. Considering the relatively lower cost of our homebuilt DNP system and the relative simplicity of its design, the dissolution DNP setup reported here could be feasibly adapted for in vitro or in vivo hyperpolarized (13) C NMR or magnetic resonance imaging at least in the pre-clinical setting. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  2. Underwater Communications for Video Surveillance Systems at 2.4 GHz

    PubMed Central

    Sendra, Sandra; Lloret, Jaime; Jimenez, Jose Miguel; Rodrigues, Joel J.P.C.

    2016-01-01

    Video surveillance is needed to control many activities performed in underwater environments. The use of wired media can be a problem since the material specially designed for underwater environments is very expensive. In order to transmit the images and videos wirelessly under water, three main technologies can be used: acoustic waves, which do not provide high bandwidth, optical signals, although the effect of light dispersion in water severely penalizes the transmitted signals and therefore, despite offering high transfer rates, the maximum distance is very small, and electromagnetic (EM) waves, which can provide enough bandwidth for video delivery. In the cases where the distance between transmitter and receiver is short, the use of EM waves would be an interesting option since they provide high enough data transfer rates to transmit videos with high resolution. This paper presents a practical study of the behavior of EM waves at 2.4 GHz in freshwater underwater environments. First, we discuss the minimum requirements of a network to allow video delivery. From these results, we measure the maximum distance between nodes and the round trip time (RTT) value depending on several parameters such as data transfer rate, signal modulations, working frequency, and water temperature. The results are statistically analyzed to determine their relation. Finally, the EM waves’ behavior is modeled by a set of equations. The results show that there are some combinations of working frequency, modulation, transfer rate and temperature that offer better results than others. Our work shows that short communication distances with high data transfer rates is feasible. PMID:27782095

  3. VLBI observations of the RS Canum Venaticorum binary systems UX Arietis and HR 1099 at 1.65 GHz

    NASA Technical Reports Server (NTRS)

    Mutel, R. L.; Doiron, D. J.; Phillips, R. B.; Lestrade, J. F.

    1984-01-01

    VLBI observations of the RS CVn binaries UX Arietis and HR 1099 have been made at 1.65 GHz using a three-element array with a minimum fringe spacing of 11.5 milli-arcsec. Both sources were found to be unresolved within measurement uncertainties. In both cases, the derived upper limit to the source size was comparable to the overall size of each binary system. The lower limits to the brightness temperature were 1.4 x 10 to the 10th K for UX Arietis and 2.9 x 10 to the 10th K for HR 1099. Simultaneous polarization measurements at the VLA showed 4-8 percent circular polarization and less than 2 percent linear polarization. It is found that the data are consistent with gyrosynchrotron emission from a power-law energy distribution of electrons in a magnetic field B less than or approximately equal to 6 gauss.

  4. VLBI observations of the RS Canum Venaticorum binary systems UX Arietis and HR 1099 at 1.65 GHz

    NASA Technical Reports Server (NTRS)

    Mutel, R. L.; Doiron, D. J.; Phillips, R. B.; Lestrade, J. F.

    1984-01-01

    VLBI observations of the RS CVn binaries UX Arietis and HR 1099 have been made at 1.65 GHz using a three-element array with a minimum fringe spacing of 11.5 milli-arcsec. Both sources were found to be unresolved within measurement uncertainties. In both cases, the derived upper limit to the source size was comparable to the overall size of each binary system. The lower limits to the brightness temperature were 1.4 x 10 to the 10th K for UX Arietis and 2.9 x 10 to the 10th K for HR 1099. Simultaneous polarization measurements at the VLA showed 4-8 percent circular polarization and less than 2 percent linear polarization. It is found that the data are consistent with gyrosynchrotron emission from a power-law energy distribution of electrons in a magnetic field B less than or approximately equal to 6 gauss.

  5. Wireless Channel Characterization: Modeling the 5 GHz Microwave Landing System Extension Band for Future Airport Surface Communications

    NASA Technical Reports Server (NTRS)

    Matolak, D. W.; Apaza, Rafael; Foore, Lawrence R.

    2006-01-01

    We describe a recently completed wideband wireless channel characterization project for the 5 GHz Microwave Landing System (MLS) extension band, for airport surface areas. This work included mobile measurements at large and small airports, and fixed point-to-point measurements. Mobile measurements were made via transmission from the air traffic control tower (ATCT), or from an airport field site (AFS), to a receiving ground vehicle on the airport surface. The point-to-point measurements were between ATCT and AFSs. Detailed statistical channel models were developed from all these measurements. Measured quantities include propagation path loss and power delay profiles, from which we obtain delay spreads, frequency domain correlation (coherence bandwidths), fading amplitude statistics, and channel parameter correlations. In this paper we review the project motivation, measurement coordination, and illustrate measurement results. Example channel modeling results for several propagation conditions are also provided, highlighting new findings.

  6. 60-GHz optical/wireless MIMO system integrated with optical subcarrier multiplexing and 2x2 wireless communication.

    PubMed

    Lin, Chi-Hsiang; Lin, Chun-Ting; Huang, Hou-Tzu; Zeng, Wei-Siang; Chiang, Shou-Chih; Chang, Hsi-Yu

    2015-05-04

    This paper proposes a 2x2 MIMO OFDM Radio-over-Fiber scheme based on optical subcarrier multiplexing and 60-GHz MIMO wireless transmission. We also schematically investigated the principle of optical subcarrier multiplexing, which is based on a dual-parallel Mach-Zehnder modulator (DP-MZM). In our simulation result, combining two MIMO OFDM signals to drive DP-MZM gives rise to the PAPR augmentation of less than 0.4 dB, which mitigates nonlinear distortion. Moreover, we applied a Levin-Campello bit-loading algorithm to compensate for the uneven frequency responses in the V-band. The resulting system achieves OFDM signal rates of 61.5-Gbits/s with BER of 10(-3) over 25-km SMF transmission followed by 3-m wireless transmission.

  7. 30 GHz Commercial Satellite Receivers

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Ponchak, George E.; Romanofsky, Robert R.

    1989-01-01

    NASA's research and development work in satellite communications for the past 10 years has included a major technology thrust aimed at opening the Ka frequency band to commercial exploitation. This has included the development and testing of advanced system network architectures, on-board switching and processing, multibeam and phased array antennas, and satellite and ground terminal RF and digital hardware. Development work in system hardware has focused on critical components including power amplifiers, satellite IF switch matrices, low noise receivers, baseband processors, and high data rate bandwidth efficient modems. This paper describes NASA's work in developing and testing 30 GHz low noise satellite receivers for commercial space communications uplink applications. Frequencies allotted for fixed service commercial satellite communications in the Ka band are 27.5 - 30.0 GHz for uplink transmission and 17.7 - 20.2 GHz for downlink transmission. The relatively large 2.5 GHz bandwidth lends itself to wideband, high data rate digital transmission applications.

  8. Technical specification for the Product Evaluation Management Information System (PREMIS) Version 1. 1. 2

    SciTech Connect

    Eaton, D.S.; Hall, R.C.; Orman, J.L.; Klamerus, J.

    1990-06-01

    This document contains the technical specifications and implementation details for the Product Evaluation Management Information System (PREMIS) Version 1.1.2. This document does not include the requirements analysis or design information and is not intended as a user's guide. The INGRES Applications-by-Forms (ABF) software development tool was used to specify and define the modules and screens which comprise the PREMIS application. Several external procedures are called by the ABF procedures; these have been written in VAX/VMS DCL (Digital Command Language) and SQL (Standard Query Language). These specifications together with the PREMIS information model and corresponding database definition constitute the PREMIS Version 1.1.2 technical specification and implementation description presented herein.

  9. Extraction systems using bis-1,2-dicarbollylcobaltate and polyoxonium compounds for lanthanide separations

    SciTech Connect

    Vanura, P.; Jedinakova-Krizova, V. )

    1992-12-01

    The extraction of rare earths (lanthanides, Y, Sc) by voluminous bis-1,2-dicarbollylcobaltate anions dissolved in nitrobenzene and in a nitrobenzene - carbon tetrachloride mixture has been investigated and the exchange extraction constants for both solvents, individual extraction constants and [Delta]G[sup 0] for ion transfer across the water - nitrobenzene phase boundary has been determined. Extraction decreases with increasing atomic number of the lanthanide. The influence of several polyoxonium compounds on the distribution ratios and the extraction selectivity has been investigated. In the extraction systems with bis-1,2-dicarbollylcobaltate - 18-crown-6 in nitrobenzene, synergism was found for the light lanthanides but antagonism was observed for the heavy ones. The overall separation factor is [alpha][sub La/Lu] [approx]10 compared to [alpha][sub La/Lu] [approx]2 in the absence of crown. 17 refs., 4 figs., 1 tab.

  10. Implementation and Analysis of ISM 2.4 GHz Wireless Sensor Network Systems in Judo Training Venues.

    PubMed

    Lopez-Iturri, Peio; Aguirre, Erik; Azpilicueta, Leyre; Astrain, José Javier; Villadangos, Jesús; Falcone, Francisco

    2016-08-06

    In this work, the performance of ISM 2.4 GHz Wireless Sensor Networks (WSNs) deployed in judo training venues is analyzed. Judo is a very popular martial art, which is practiced by thousands of people not only at the competition level, but also as part of physical education programs at different school levels. There is a great variety of judo training venues, and each one has specific morphological aspects, making them unique scenarios in terms of radio propagation due to the presence of furniture, columns, equipment and the presence of human beings, which is a major issue as the person density within this kind of scenarios could be high. Another key aspect is the electromagnetic interference created by other wireless systems, such as WiFi or other WSNs, which make the radio planning a complex task in terms of coexistence. In order to analyze the impact of these features on the radio propagation and the performance of WSNs, an in-house developed 3D ray launching algorithm has been used. The obtained simulation results have been validated with a measurement campaign carried out in the sport facilities of the Public University of Navarre. The analysis is completed with the inclusion of an application designed to monitor biological constants of judokas, aimed to improve their training procedures. The application, that allows the simultaneous monitoring of multiple judokas (collective workouts) minimizing the efforts of the coach and medical supervisor, is based on commercial off-the-shelf products. The presented assessment of the presence of interfering wireless systems and the presence of human beings within judo training venues shows that an in-depth radio planning is required as these issues can have a great impact in the overall performance of a ISM 2.4 GHz WSN, affecting negatively the potential applications supported by wireless channel.

  11. Implementation and Analysis of ISM 2.4 GHz Wireless Sensor Network Systems in Judo Training Venues

    PubMed Central

    Lopez-Iturri, Peio; Aguirre, Erik; Azpilicueta, Leyre; Astrain, José Javier; Villadangos, Jesús; Falcone, Francisco

    2016-01-01

    In this work, the performance of ISM 2.4 GHz Wireless Sensor Networks (WSNs) deployed in judo training venues is analyzed. Judo is a very popular martial art, which is practiced by thousands of people not only at the competition level, but also as part of physical education programs at different school levels. There is a great variety of judo training venues, and each one has specific morphological aspects, making them unique scenarios in terms of radio propagation due to the presence of furniture, columns, equipment and the presence of human beings, which is a major issue as the person density within this kind of scenarios could be high. Another key aspect is the electromagnetic interference created by other wireless systems, such as WiFi or other WSNs, which make the radio planning a complex task in terms of coexistence. In order to analyze the impact of these features on the radio propagation and the performance of WSNs, an in-house developed 3D ray launching algorithm has been used. The obtained simulation results have been validated with a measurement campaign carried out in the sport facilities of the Public University of Navarre. The analysis is completed with the inclusion of an application designed to monitor biological constants of judokas, aimed to improve their training procedures. The application, that allows the simultaneous monitoring of multiple judokas (collective workouts) minimizing the efforts of the coach and medical supervisor, is based on commercial off-the-shelf products. The presented assessment of the presence of interfering wireless systems and the presence of human beings within judo training venues shows that an in-depth radio planning is required as these issues can have a great impact in the overall performance of a ISM 2.4 GHz WSN, affecting negatively the potential applications supported by wireless channel. PMID:27509501

  12. Hub-filament System in IRAS 05480+2545: Young Stellar Cluster and 6.7 GHz Methanol Maser

    NASA Astrophysics Data System (ADS)

    Dewangan, L. K.; Ojha, D. K.; Baug, T.

    2017-07-01

    To probe the star formation (SF) process, we present a multi-wavelength study of IRAS 05480+2545 (hereafter I05480+2545). Analysis of Herschel data reveals a massive clump (M clump ˜ 1875 {M}⊙ ; peak N(H2) ˜ 4.8 × 1022 cm-2 A V ˜ 51 mag) containing the 6.7 GHz methanol maser and I05480+2545, which is also depicted in a temperature range of 18-26 K. Several noticeable parsec-scale filaments are detected in the Herschel 250 μm image and seem to be radially directed to the massive clump. It resembles more of a “hub-filament” system. Deeply embedded young stellar objects (YSOs) have been identified using the 1-5 μm photometric data, and a significant fraction of YSOs and their clustering are spatially found toward the massive clump, revealing the intense SF activities. An infrared counterpart (IRc) of the maser is investigated in the Spitzer 3.6-4.5 μm images. The IRc does not appear as a point-like source and is most likely associated with the molecular outflow. Based on the 1.4 GHz and Hα continuum images, the ionized emission is absent toward the IRc, indicating that the massive clump harbors an early phase of a massive protostar before the onset of an ultracompact H ii region. Together, the I05480+2545 is embedded in a very similar “hub-filament” system to those seen in the Rosette Molecular Cloud. The outcome of the present work indicates the role of filaments in the formation of the massive star-forming clump and cluster of YSOs, which might help channel material to the central hub configuration and the clump/core.

  13. Frequency sharing between passive sensors and aeronautical radionavigation systems employing ground transponders in the band 4.2 - 4.4 GHz

    NASA Technical Reports Server (NTRS)

    Degroot, N. F.

    1982-01-01

    The 4.2 to 4.4 GHz band is reserved for radio altimeters aboard aircraft and for associated transponders on the ground. A radar altimeter system which utilizes associated ground transponders is described and the feasibility of co-channel operation of such a system with a typical passive sensor is analyzed.

  14. Development and Preliminary Commissioning Results of a Long Pulse 140 GHz ECRH System on EAST Tokamak (Invited)

    NASA Astrophysics Data System (ADS)

    Xu, Handong; Wang, Xiaojie; Liu, Fukun; Zhang, Jian; Huang, Yiyun; Shan, Jiafang; Wu, Dajun; Hu, Huaichuan; Li, Bo; Li, Miaohui; Yang, Yong; Feng, Jianqiang; Xu, Weiye; Tang, Yunying; Wei, Wei; Xu, Liqing; Liu, Yong; Zhao, Hailin; Lohr, J.; A. Gorelov, Y.; P. Anderson, J.; Ma, Wendong; Wu, Zege; Wang, Jian; Zhang, Liyuan; Guo, Fei; Sun, Haozhang; Yan, Xinsheng; East Team

    2016-04-01

    A long pulse electron cyclotron resonance heating (ECRH) system has been developed to meet the requirements of steady-state operation for the EAST superconducting tokamak, and the first EC wave was successfully injected into plasma during the 2015 spring campaign. The system is mainly composed of four 140 GHz gyrotron systems, 4 ITER-Like transmission lines, 4 independent channel launchers and corresponding power supplies, a water cooling, control & inter-lock system etc. Each gyrotron is expected to deliver a maximum power of 1 MW and be operated at 100-1000 s pulse lengths. The No.1 and No.2 gyrotron systems have been installed. In the initial commissioning, a series of parameters of 1 MW 1 s, 900 kW 10 s, 800 kW 95 s and 650 kW 753 s have been demonstrated successfully on the No.1 gyrotron system based on calorimetric dummy load measurements. Significant plasma heating and MHD instability suppression effects were observed in EAST experiments. In addition, high confinement (H-mode) discharges triggered by ECRH were obtained. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2011GB102000, 2012GB103000 and 2015GB103000)

  15. Federal Emergency Management Information System (FEMIS) system administration guide. Version 1.2

    SciTech Connect

    Burford, M.J.; Burnett, R.A.; Curtis, L.M.

    1996-05-01

    The Federal Emergency Management Information System (FEMIS) is an emergency management planning and analysis tool that is being developed under the direction of the US Army Chemical biological Defense Command. The FEMIS System Administration Guide defines FEMIS hardware and software requirements and gives instructions for installing the FEMIS system package. System administrators, database administrators, and general users can use this guide to install, configure, and maintain the FEMIS client software package. This document provides a description of the FEMIS environment; distribution media; data, communications, and electronic mail servers; user workstations; and system management.

  16. Quantum simulation of Abelian Wu–Yang monopoles in spin-1/2 systems

    NASA Astrophysics Data System (ADS)

    Zhang, Ze-Lin; Chen, Ming-Feng; Wu, Huai-Zhi; Yang, Zhen-Biao

    2017-04-01

    With the help of the Berry curvature and the first Chern number (C 1), we both analytically and numerically investigate and thus simulate artificial magnetic monopoles formed in parameter space of the Hamiltonian of a driven superconducting qubit. The topological structure of a spin-1/2 system (qubit) can be captured by the distribution of Berry curvature, which describes the geometry of eigenstates of the Hamiltonian. Degenerate points in parameter space act as sources (C 1  =  1, represented by quantum ground state manifold) or sinks (C 1  =  ‑1, represented by quantum excited state manifold) of the magnetic field. We note that the strength of the magnetic field (described by Berry curvature) has an apparent impact on the quantum states during the process of topological transition. It exhibits an unusual property that the transition of the quantum states is asymmetric when the degenerate point passes from outside to inside and again outside the manifold spanned by system parameters. Our results also pave the way to explore intriguing properties of Abelian Wu–Yang monopoles in other spin-1/2 systems.

  17. Ultrahigh capacity 2 × 2 MIMO RoF system at 60  GHz employing single-sideband single-carrier modulation.

    PubMed

    Lin, Chun-Ting; Ho, Chun-Hung; Huang, Hou-Tzu; Cheng, Yu-Hsuan

    2014-03-15

    This article proposes and experimentally demonstrates a radio-over-fiber system employing single-sideband single-carrier (SSB-SC) modulation at 60 GHz. SSB-SC modulation has a lower peak-to-average-power ratio than orthogonal frequency division multiplex (OFDM) modulation; therefore, the SSB-SC signals provide superior nonlinear tolerance, compared to OFDM signals. Moreover, multiple-input multiple-output (MIMO) technology was used extensively to enhance spectral efficiency. A least-mean-square-based equalizer was implemented, including MIMO channel estimation, frequency response equalization, and I/Q imbalance compensation to recover the MIMO signals. Thus, using 2×2 MIMO technology and 64-QAM SSB-SC signals, we achieved the highest data rate of 84 Gbps with 12  bit/s/Hz spectral efficiency using the 7-GHz license-free band at 60 GHz.

  18. Broadband Upgrade for the 1.668-GHz (L-Band) Radio Astronomy Feed System on the DSN 70-m Antennas

    NASA Astrophysics Data System (ADS)

    Hoppe, D.; Khayatian, B.; Lopez, B.; Torrez, T.; Long, E.; Sosnowski, J.; Franco, M.; Teitelbaum, L.

    2015-08-01

    Currently, each of the three Deep Space Network (DSN) 70-m antennas provides a narrowband, 1.668-GHz (L-band) receive capability for radio astronomy observations. This capability is delivered by a large feedhorn mounted on the exterior of one of the feedcones. It provides a single polarization into a pair of redundant low-noise amplifiers. Recently, funding was obtained to upgrade this system to wideband (1.4-1.9 GHz) dual-polarization operation. This required development of a new feedhorn, polarizer, orthomode transducer (OMT), and waveguide transitions. In this article, we describe the design and laboratory testing of these components.

  19. A network control concept for the 30/20 GHz communication system baseband processor

    NASA Technical Reports Server (NTRS)

    Sabourin, D. J.; Hay, R. E.

    1982-01-01

    The architecture and system design for a satellite-switched TDMA communication system employing on-board processing was developed by Motorola for NASA's Lewis Research Center. The system design is based on distributed processing techniques that provide extreme flexibility in the selection of a network control protocol without impacting the satellite or ground terminal hardware. A network control concept that includes system synchronization and allows burst synchronization to occur within the system operational requirement is described. This concept integrates the tracking and control links with the communication links via the baseband processor, resulting in an autonomous system operational approach.

  20. Nonlinear quantum-mechanical system associated with Sine-Gordon equation in (1 + 2) dimensions

    SciTech Connect

    Zarmi, Yair

    2014-10-15

    Despite the fact that it is not integrable, the (1 + 2)-dimensional Sine-Gordon equation has N-soliton solutions, whose velocities are lower than the speed of light (c = 1), for all N ≥ 1. Based on these solutions, a quantum-mechanical system is constructed over a Fock space of particles. The coordinate of each particle is an angle around the unit circle. U, a nonlinear functional of the particle number-operators, which obeys the Sine-Gordon equation in (1 + 2) dimensions, is constructed. Its eigenvalues on N-particle states in the Fock space are the slower-than-light, N-soliton solutions of the equation. A projection operator (a nonlinear functional of U), which vanishes on the single-particle subspace, is a mass-density generator. Its eigenvalues on multi-particle states play the role of the mass density of structures that emulate free, spatially extended, relativistic particles. The simplicity of the quantum-mechanical system allows for the incorporation of perturbations with particle interactions, which have the capacity to “annihilate” and “create” solitons – an effect that does not have an analog in perturbed classical nonlinear evolution equations.

  1. Molecular hydrogen and excitation in the HH 1-2 system

    NASA Technical Reports Server (NTRS)

    Noriega-Crespo, A.; Garnavich, P. M.

    1994-01-01

    We present a series of molecular hydrogen images of the Herbig-Haro 1-2 system in the 1-0 S(1) transition at 2.121 microns, with a spatial resolution of approximately 2 sec. The distribution of H2 is then compared with that of the excitation, given by the (S II) 6717+6731 to H-alpha line ratio. We find that most optical condensations in the HH 1-2 system, including the VLA 1 jet, have H2 counterparts. H2 emission is detected in most low excitation knots, as expected for low velocity shocks (50 km/s less than), but also in high excitation regions, like in HH 1F and HH 2A min. For these latter objects, the H2 emission could be due to the interaction of the preionizing flux, produced by 150-200 km/s shocks, with the surrounding interstellar matter, i.e., fluorescence. The lack fluorescent lines in the ultraviolet (UV), however, suggest a different mechanism. H2 is detected at the tip of the VLA 1 jet, where the knot morphology suggests the presence of a second bow shock. H2 is detected also SE of HH 2E and SW of HH 1F, in regions with known NH3 emission.

  2. Molecular hydrogen and excitation in the HH 1-2 system

    NASA Technical Reports Server (NTRS)

    Noriega-Crespo, A.; Garnavich, P. M.

    1994-01-01

    We present a series of molecular hydrogen images of the Herbig-Haro 1-2 system in the 1-0 S(1) transition at 2.121 microns, with a spatial resolution of approximately 2 sec. The distribution of H2 is then compared with that of the excitation, given by the (S II) 6717+6731 to H-alpha line ratio. We find that most optical condensations in the HH 1-2 system, including the VLA 1 jet, have H2 counterparts. H2 emission is detected in most low excitation knots, as expected for low velocity shocks (50 km/s less than), but also in high excitation regions, like in HH 1F and HH 2A min. For these latter objects, the H2 emission could be due to the interaction of the preionizing flux, produced by 150-200 km/s shocks, with the surrounding interstellar matter, i.e., fluorescence. The lack fluorescent lines in the ultraviolet (UV), however, suggest a different mechanism. H2 is detected at the tip of the VLA 1 jet, where the knot morphology suggests the presence of a second bow shock. H2 is detected also SE of HH 2E and SW of HH 1F, in regions with known NH3 emission.

  3. Quantum refrigeration cycles using spin-1/2 systems as the working substance.

    PubMed

    He, Jizhou; Chen, Jincan; Hua, Ben

    2002-03-01

    The cycle model of a quantum refrigerator composed of two isothermal and two isomagnetic field processes is established. The working substance in the cycle consists of many noninteracting spin-1/2 systems. The performance of the cycle is investigated, based on the quantum master equation and semigroup approach. The general expressions of several important performance parameters, such as the coefficient of performance, cooling rate, and power input, are given. Especially, the case at high temperatures is analyzed in detail. The results obtained are further generalized and discussed, so that they may be directly used to describe the performance of the quantum refrigerator using spin-J systems as the working substance. Finally, the optimum characteristics of the quantum Carnot refrigerator are derived simply.

  4. Weather monitor station and 225 GHz radiometer system installed at Sierra Negra: the Large Millimeter Telescope site

    NASA Astrophysics Data System (ADS)

    Ferrusca, D.; Contreras R., J.

    2014-07-01

    The Large Millimeter Telescope (LMT) is a 50-m dish antenna designed to observe in the wavelength range of 0.85 to 4 mm at an altitude of 4600 m on the summit of Sierra Negra Puebla, Mexico. The telescope has a new atmospheric monitoring system that allows technical staff and astronomers to evaluate the conditions at the site and have enough information to operate the antenna in safe conditions, atmospheric data is also useful to schedule maintenance activities and conduct scientific observations, opacity data is used to calibrate the astronomical data and evaluate the quality of the sky at millimeter wavelengths. In this paper we describe the integration of a weather atmospheric monitoring system and a 225 GHz radiometer to the facilities around the telescope and also describe the hardware integration of these systems and the software methodology used to save and process the data and then make it available in real time to the astronomers and outside world through an internet connection. Finally we present a first set of atmospheric measurements and statistics taken with this new equipment during the wet and dry seasons of 2013/2014.

  5. Single-chip electron spin resonance detectors operating at 50 GHz, 92 GHz, and 146 GHz

    NASA Astrophysics Data System (ADS)

    Matheoud, Alessandro V.; Gualco, Gabriele; Jeong, Minki; Zivkovic, Ivica; Brugger, Jürgen; Rønnow, Henrik M.; Anders, Jens; Boero, Giovanni

    2017-05-01

    We report on the design and characterization of single-chip electron spin resonance (ESR) detectors operating at 50 GHz, 92 GHz, and 146 GHz. The core of the single-chip ESR detectors is an integrated LC-oscillator, formed by a single turn aluminum planar coil, a metal-oxide-metal capacitor, and two metal-oxide semiconductor field effect transistors used as negative resistance network. On the same chip, a second, nominally identical, LC-oscillator together with a mixer and an output buffer are also integrated. Thanks to the slightly asymmetric capacitance of the mixer inputs, a signal at a few hundreds of MHz is obtained at the output of the mixer. The mixer is used for frequency down-conversion, with the aim to obtain an output signal at a frequency easily manageable off-chip. The coil diameters are 120 μm, 70 μm, and 45 μm for the U-band, W-band, and the D-band oscillators, respectively. The experimental frequency noises at 100 kHz offset from the carrier are 90 Hz/Hz1/2, 300 Hz/Hz1/2, and 700 Hz/Hz1/2 at 300 K, respectively. The ESR spectra are obtained by measuring the frequency variations of the single-chip oscillators as a function of the applied magnetic field. The experimental spin sensitivities, as measured with a sample of α,γ-bisdiphenylene-β-phenylallyl (BDPA)/benzene complex, are 1 × 108 spins/Hz1/2, 4 × 107 spins/Hz1/2, 2 × 107 spins/Hz1/2 at 300 K, respectively. We also show the possibility to perform experiments up to 360 GHz by means of the higher harmonics in the microwave field produced by the integrated single-chip LC-oscillators.

  6. MMIC Amplifiers for 90 to 130 GHz

    NASA Technical Reports Server (NTRS)

    Samoska, Lorene; Pukala, David; Peralta, Alejandro; Bryerton, Eric; Morgan, Matt; Boyd, T.; Hu, Ming; Schmitz, Adele

    2007-01-01

    This brief describes two monolithic microwave integrated-circuit (MMIC) amplifier chips optimized to function in the frequency range of 90 to 130 GHz, covering nearly all of F-band (90 - 140 GHz). These amplifiers were designed specifically for local-oscillator units in astronomical radio telescopes such as the Atacama Large Millimeter Array (ALMA). They could also be readily adapted for use in electronic test equipment, automotive radar systems, and communications systems that operate between 90 and 130 GHz.

  7. A 90-GHz Photoinjector

    SciTech Connect

    Palmer, D.T.; Hogan, M.J.; Ferrario, M.; Serafini, L.; /Frascati /INFN, Milan

    2005-09-12

    Photocathode rf guns depend on mode locked laser systems to produce an electron beam at a given phase of the rf. In general, the laser pulse is less than {sigma}{sub z} = 10{sup o} of rf phase in length and the required stability is on the order of {Delta}{phi} = 1{sup o}. At 90 GHz (W-band), these requirements correspond to {sigma}{sub z} = 333 fsec and {Delta}{phi} = 33 fsec. Laser system with pulse lengths in the fsec regime are commercially available, the timing stability is a major concern. We propose a multi-cell W-band photoinjector that does not require a mode locked laser system. Thereby eliminating the stability requirements at W-band. The laser pulse is allowed to be many rf periods long. In principle, the photoinjector can now be considered as a thermionic rf gun. Instead of using an alpha magnet to compress the electron bunch, which would have a detrimental effect on the transverse phase space quality due to longitudinal phase space mixing, we propose to use long pulse laser system and a pair of undulators to produce a low emittance, high current, ultra-short electron bunch for beam dynamics experiments in the 90 GHz regime.

  8. A large size ion beam figuring system for 1.2m astronomical telescopes fabrication

    NASA Astrophysics Data System (ADS)

    Xie, Xuhui; Yang, Bing; Zhou, Lin; Song, Ci; Hu, Hao

    2016-07-01

    An ion beam figuring system (KDIBF2000) for final figuring of large size optics has been designed and built by National University of Defense Technology in China. It can figure optics up to the maximum dimensions of 2.0m×2.0m×0.4m with five axes of servo-motion used to control ion source movement. For operational facility, there are two vacuum chambers with main work chamber and a small supplementary chamber isolated by a flapper valve. The main chamber has two work zones, which can meantime hold a large optics with Φ1.5m and a small optics with 0.4m. The small optics can be transferred through supplementary chamber with a moving vehicle. By this way, it is very convenient and economical to gain the material removal function and check the system's process performance. Now, this system has been gone into running to figure large SiC off-axis aspheric optics. Next step, a 1.2m SiC aspheric primary mirror will be figure by this system.

  9. Multifrequency resonances in multiple-pulse NMR on a spin-1/2 system

    SciTech Connect

    Furman, G.B.; Goren, S.D.; Meerovich, V.M.; Sokolovsky, V.L.; Kibrik, G.E.; Polyakov, A.Yu.

    2003-12-01

    We have observed multifrequency resonances in a system with a spin 1/2 located in dc magnetic field and irradiated simultaneously by a multiple-pulse radio frequency sequence and a low-frequency field swept in the range 0-80 kHz. The used excitation scheme allowed us to measure the effective field of the radio frequency sequence. A peculiarity of this scheme is that the intensity of the resonance lines decreases slowly with the mode number. The theoretical description of the effect is presented using both the rotating frame approximation and the Floquet theory. Both approaches give identical results at the calculation of the resonance frequencies, transition probabilities, and shifts of resonance frequency. The calculated magnetization vs the frequency of the low-frequency field agrees well with the obtained experimental data. The multifrequency spectra give a way for studying slow atomic motion in solids.

  10. Ecological optimization of an irreversible quantum Carnot heat engine with spin-1/2 systems

    NASA Astrophysics Data System (ADS)

    Liu, Xiaowei; Chen, Lingen; Wu, Feng; Sun, Fengrui

    2010-02-01

    A model of a quantum heat engine with heat resistance, internal irreversibility and heat leakage and many non-interacting spin-1/2 systems is established in this paper. The quantum heat engine cycle is composed of two isothermal processes and two irreversible adiabatic processes and is referred to as a spin quantum Carnot heat engine. Based on the quantum master equation and the semi-group approach, equations of some important performance parameters, such as power output, efficiency, entropy generation rate and ecological function (a criterion representing the optimal compromise between exergy output rate and exergy loss rate), for the irreversible spin quantum Carnot heat engine are derived. The optimal ecological performance of the heat engine in the classical limit is analyzed with numerical examples. The effects of internal irreversibility and heat leakage on ecological performance are discussed in detail.

  11. YAC 1.2.0: new aspects for coupling software in Earth system modelling

    NASA Astrophysics Data System (ADS)

    Hanke, Moritz; Redler, René; Holfeld, Teresa; Yastremsky, Maxim

    2016-08-01

    A lightweight software library has been developed to realise the coupling of Earth system model components. The software provides parallelised two-dimensional neighbourhood search, interpolation, and communication for the coupling between any two model components. The software offers flexible coupling of physical fields defined on regular and irregular grids on the sphere without a priori assumptions about grid structure or grid element types. All supported grids can be combined with any of the supported interpolations. We describe the new aspects of our approach and provide an overview of the implemented functionality and of some algorithms we use. Preliminary performance measurements for a set of realistic use cases are presented to demonstrate the potential performance and scalability of our approach. YAC 1.2.0 is now used for the coupling of the model components in the Icosahedral Nonhydrostatic (ICON) general circulation model.

  12. Triple quantum filtered spectroscopy of homonuclear three spin-1/2 systems employing isotropic mixing

    NASA Astrophysics Data System (ADS)

    Kirwai, Amey; Chandrakumar, N.

    2016-08-01

    We report the design and performance evaluation of novel pulse sequences for triple quantum filtered spectroscopy in homonuclear three spin-1/2 systems, employing isotropic mixing (IM) to excite triple quantum coherence (TQC). Our approach involves the generation of combination single quantum coherences (cSQC) from antisymmetric longitudinal or transverse magnetization components employing isotropic mixing (IM). cSQC's are then converted to TQC by a selective 180° pulse on one of the spins. As IM ideally causes magnetization to evolve under the influence of the spin coupling Hamiltonian alone, TQC is generated at a faster rate compared to sequences involving free precession. This is expected to be significant when the spins have large relaxation rates. Our approach is demonstrated experimentally by TQC filtered 1D spectroscopy on a 1H AX2 system (propargyl bromide in the presence of a paramagnetic additive), as well as a 31P linear AMX system (ATP in agar gel). The performance of the IM-based sequences for TQC excitation are compared against the standard three pulse sequence (Ernst et al., 1987) and an AX2 spin pattern recognition sequence (Levitt and Ernst, 1983). The latter reaches the unitary bound on TQC preparation efficiency starting from thermal equilibrium in AX2 systems, not considering relaxation. It is shown that in systems where spins relax rapidly, the new IM-based sequences indeed perform significantly better than the above two known TQC excitation sequences, the sensitivity enhancement being especially pronounced in the case of the proton system investigated. An overview of the differences in relaxation behavior is presented for the different approaches. Applications are envisaged to Overhauser DNP experiments and to in vivo NMR.

  13. A New Solid/Liquid Hypergolic System: 3-amino 1,2,4-triazine and Nitric Acid

    DTIC Science & Technology

    2016-04-01

    ARL-TN-0750 ● APR 2016 US Army Research Laboratory A New Solid/Liquid Hypergolic System: 3- amino -1,2,4-triazine and Nitric Acid ...APR 2016 US Army Research Laboratory A New Solid/Liquid Hypergolic System: 3- amino -1,2,4-triazine and Nitric Acid by William M...

  14. Scanning beam antenna conceptual design for 20/30 GHz satellite systems

    NASA Technical Reports Server (NTRS)

    Smetana, J.; Sorbello, R.; Crosswell, W. F.

    1983-01-01

    The configuration described is one of four antenna system configurations developed using a variety of monolithic microwave integrated circuit module arrangements and optical systems. A parametric analysis is expected to produce a data base for the selection of design points for a variety of applications. Soon to be accomplished is the design concept of the active (lens) array, which will take into consideration such factors as, coupling effects, the space-fed power divider network design, input bias and control layout, investigation of thermal distribution, and analysis of module failure (graceful degradation).

  15. Propagation effects handbook for satellite systems design. A summary of propagation impairments on 10 to 100 GHz satellite links with techniques for system design

    NASA Technical Reports Server (NTRS)

    Ippolito, Louis J.

    1989-01-01

    The NASA Propagation Effects Handbook for Satellite Systems Design provides a systematic compilation of the major propagation effects experienced on space-Earth paths in the 10 to 100 GHz frequency band region. It provides both a detailed description of the propagation phenomenon and a summary of the impact of the effect on the communications system design and performance. Chapter 2 through 5 describe the propagation effects, prediction models, and available experimental data bases. In Chapter 6, design techniques and prediction methods available for evaluating propagation effects on space-Earth communication systems are presented. Chapter 7 addresses the system design process and how the effects of propagation on system design and performance should be considered and how that can be mitigated. Examples of operational and planned Ku, Ka, and EHF satellite communications systems are given.

  16. Biodegradation of cis-1,2-Dichloroethene in Simulated Underground Thermal Energy Storage Systems.

    PubMed

    Ni, Zhuobiao; van Gaans, Pauline; Smit, Martijn; Rijnaarts, Huub; Grotenhuis, Tim

    2015-11-17

    Underground thermal energy storage (UTES) use has showed a sharp rise in numbers in the last decades, with aquifer thermal energy storage (ATES) and borehole thermal energy storage (BTES) most widely used. In many urban areas with contaminated aquifers, there exists a desire for sustainable heating and cooling with UTES and a need for remediation. We investigated the potential synergy between UTES and bioremediation with batch experiments to simulate the effects of changing temperature and liquid exchange that occur in ATES systems, and of only temperature change occurring in BTES systems on cis-DCE reductive dechlorination. Compared to the natural situation (NS) at a constant temperature of 10 °C, both UTES systems with 25/5 °C for warm and cold well performed significantly better in cis-DCE (cis-1,2-dichloroethene) removal. The overall removal efficiency under mimicked ATES and BTES conditions were respectively 13 and 8.6 times higher than in NS. Inoculation with Dehalococcoides revealed that their initial presence is a determining factor for the dechlorination process. Temperature was the dominating factor when Dehalococcoides abundance was sufficient. Stimulated biodegradation was shown to be most effective in the mimicked ATES warm well because of the combined effect of suitable temperature, sustaining biomass growth, and regular cis-DCE supply.

  17. The 20 and 30 GHz MMIC technology for future space communication antenna system

    NASA Technical Reports Server (NTRS)

    Anzic, G.; Connolly, D. J.

    1984-01-01

    The development of fully monolithic gallium arsenide receive and transmit modules is described. These modules are slated for phased array antenna applications in future 30/20 gigahertz communications satellite systems. Performance goals and various approaches to achieve them are discussed. The latest design and performance results of components, submodules and modules are presented.

  18. A comparative evaluation of bracket bonding with 1-, 2-, and 3-component adhesive systems.

    PubMed

    Faltermeier, Andreas; Behr, Michael; Müssig, Dieter

    2007-08-01

    Today, 1- and 2-component adhesives are available for bracket bonding that could diminish the possibility of contamination during the bonding procedure and save the clinician chair-side time. Our aim in this study was to compare the shear bond strengths and the adhesive remnant index (ARI) scores of 1-, 2-, and 3-component adhesives after thermocycling. Fifty stainless steel brackets (10 per adhesive group) were bonded to extracted third molars with 5 adhesives. Group 1 was a 1-component adhesive, RelyX Unicem (3M Espe, Seefeld, Germany). Group 2 was a 1-component adhesive, Maxcem (Kerr, Orange, Calif). Group 3 was a self-conditioning 2-component adhesive system, Multilink (Ivoclar-Vivadent, Schaan, Liechtenstein). Group 4 was a 2-component adhesive system, Transbond Plus primer (self-etching) and Transbond XT adhesive (3M Unitek, Monrovia, Calif). Group 5 (control group) was a conventional 3-component adhesive system consisting of an etchant, Transbond XT primer, and XT adhesive (3M Unitek). All samples were thermocycled (6000 x 5 degrees C/55 degrees C) in a mastication device before shear bond strength testing and evaluation with the ARI. No significant differences of shear bond strength between the 2- and 3-component adhesive systems were found. Significant decreases of shear bond strength were observed with 1-component adhesives, RelyX Unicem and Maxcem, compared with 2- and 3-component systems. The ARI scores indicated no significant differences between the groups. With enhanced shear bond strength, 1- component adhesives have the potential to compete successfully with 2- or 3-component adhesives.

  19. Antennas in the 20/30 GHz band for the ground segment of the Italsat system

    NASA Astrophysics Data System (ADS)

    Adamou, A.; Pagana, E.; Saitto, A.; Vatalaro, F.

    A description is given of two antenna standards that were assessed to be capable of assuring the required service quality and availability. Both antennas have an offset configuration with three reflectors. The main reflector is a paraboloid which is realized with carbon-fiber multilayered materials. The two shaped metallic subreflectors and a specially designed feed system incorporating a frequency selective surface allow a compact antenna structure design that provides high gain, low sidelobes, and good cross-polarization performance.

  20. The Upgrade of the DIII-D GHz ECH System to 6 MW

    SciTech Connect

    Cary, W.P.; Callis, R.W.; Lohr, J.M.; Ponce, D.; Legg, R.A.

    1999-11-01

    ECH power has proven capabilities to both heat and drive current in energetic plasmas. Recent developments in high power sources have made the use of these capabilities in energetic plasmas feasible. For the second phase of ECH power on DIII-D, there will be three 1 MW sources added to the existing 3 MW for a total generated power of 6 MW. The upgrade is based on the use of single disc CVD (chemical vapor deposition) diamond windows on 1 MW gyrotrons developed by CPI. AU gyrotrons are connected to the tokamak by low-loss-windowless evacuated transmission lines using circular corrugated waveguide for propagation in the HE{sub 11} mode. Each waveguide system incorporates a two-mirror launcher which can steer the rf beam poloidally from the center to the outer edge of the plasma and toroidally for either co- or counter-current drive. The total system overview and integration with existing systems will be discussed along with the new aspects of the upgrade from building modifications to the new launchers. Much of the upgrade is comprised of existing designs, which will need only slight modifications, while some components have required new designs because of longer pulse lengths.

  1. Design and Implementation of a 200kW, 28GHz gyrotron system for the Compact Toroidal Hybrid Experiment

    NASA Astrophysics Data System (ADS)

    Hartwell, G. J.; Knowlton, S. F.; Ennis, D. A.; Maurer, D. A.; Bigelow, T.

    2016-10-01

    The Compact Toroidal Hybrid (CTH) is an l = 2 , m = 5 torsatron/tokamak hybrid (R0 = 0.75 m, ap 0.2 m, and | B | <= 0.7 T). It can generate its highly configurable confining magnetic fields solely with external coils, but typically operates with up to 80 kA of ohmically-generated plasma current for heating. New studies of edge plasma transport in stellarator geometries will benefit from CTH operating as a pure torsatron with a high temperature edge plasma. Accordingly, a 28 GHz, 200 kW gyrotron operating at 2nd harmonic for ECRH is being installed to supplement the existing 15 kW klystron system operating at the fundamental frequency; the latter will be used to initially generate the plasma. Ray-tracing calculations that guide the selection of launching position, antenna focal length, and beam-steering characteristics of the ECRH have been performed with the TRAVIS code [ 1 ] . The calculated absorption is up to 95.7% for vertically propagating rays, however, the absorption is more sensitive to magnetic field variations than for a side launch where the field gradient is tokamak-like. The design of the waveguide path and components for the top-launch scenario will be presented. This work is supported by U.S. Department of Energy Grant No. DE-FG02-00ER54610.

  2. A propagation effects handbook for satellite systems design. A summary of propagation impairments on 10-100 GHz satellite links, with techniques for system design. [tropospheric scattering

    NASA Technical Reports Server (NTRS)

    Kaul, R.; Wallace, R.; Kinal, G.

    1980-01-01

    This handbook provides satellite system engineers with a concise summary of the major propagation effects experienced on Earth-space paths in the 10 to 100 GHz frequency range. The dominant effect, attenuation due to rain, is dealt with in terms of both experimental data from measurements made in the U.S. and Canada, and the mathematical and conceptual models devised to explain the data. Rain systems, rain and attenuation models, depolarization and experimental data are described. The design techniques recommended for predicting propagation effects in Earth-space communications systems are presented. The questions of where in the system design process the effects of propagation should be considered, and what precautions should be taken when applying the propagation results are addressed in order to bridge the gap between the propagation research data and the classical link budget analysis of Earth-space communications system.

  3. Design of 2-4 GHz Equalizers for the Antiproton Accumulator Stacktail System

    SciTech Connect

    Deibele, C.; /Wisconsin U., Madison

    1999-01-01

    The antiproton source at Fermilab requires storage of antiprotons during the production of antiprotons. A fundamental part of the storage process involves stochastic cooling, which requires that the frequency spectrum from the pickups has notches at the revolution frequency and harmonics of the revolution frequency of the antiprotons in the storage ring. A system has been developed for broadband notches but suffers from dispersion. The dispersion inhibits the cooling process and therefore an equalizer is required. The process for designing the equalizers is described and results shown.

  4. An Optimized 2.4GHz RF Power Amplifier Performance for WLAN System

    NASA Astrophysics Data System (ADS)

    Ali, Mohammed H.; Chakrabarty, C. K.; Abdalla, Ahmed N.; Hock, Goh C.

    2013-06-01

    Recently, the design of RF power amplifiers (PAs) for modern wireless systems are faced with a difficult tradeoff for example, cellphone; battery lifetime is largely determined by the power efficiency of the PA and high spectral efficiency which have ability to transmit data at the highest possible rate for a given channel bandwidth. This paper presents the design a multi stage class AB power Amplifier with high power added efficiency (PAE) and acceptable linearity for the WLAN applications. The open-circuited third harmonic control circuit enhances the efficiency of the PA without deteriorating the linearity of class-AB mode of the PA. The voltage and current waveforms are simulated to evaluate the appropriate operation for the modes. The effectiveness of the proposed controller has been verified by comparing proposed method with another methods using simulation study under a variety of conditions. The proposed circuit operation for a WLAN signals delivers a power-added efficiency (PAE) of 37.6% is measured at 31.6-dBm output power while dissipating 34.61 mA from a 1.8V supply. Finally, the proposed PA is show a good and acceptable result for the WLAN system.

  5. Alternative laser system for cesium magneto-optical trap via optical injection locking to sideband of a 9-GHz current-modulated diode laser.

    PubMed

    Diao, Wenting; He, Jun; Liu, Zhi; Yang, Baodong; Wang, Junmin

    2012-03-26

    By optical injection of an 852-nm extended-cavity diode laser (master laser) to lock the + 1-order sideband of a ~9-GHz-current-modulated diode laser (slave laser), we generate a pair of phase-locked lasers with a frequency difference up to ~9-GHz for a cesium (Cs) magneto-optical trap (MOT) with convenient tuning capability. For a cesium MOT, the master laser acts as repumping laser, locked to the Cs 6S₁/₂ (F = 3) - 6P₃/₂ (F' = 4) transition. When the + 1-order sideband of the 8.9536-GHz-current-modulated slave laser is optically injection-locked, the carrier operates on the Cs 6S₁/₂ (F = 4) - 6P₃/₂ (F' = 5) cooling cycle transition with -12 MHz detuning and acts as cooling/trapping laser. When carrying a 9.1926-GHz modulation signal, this phase-locked laser system can be applied in the fields of coherent population trapping and coherent manipulation of Cs atomic ground states.

  6. Studying integrated silicon-lens antennas for radio communication systems operated in the 60 GHz frequency band

    NASA Astrophysics Data System (ADS)

    Artemenko, A. A.; Mal'tsev, A. A.; Maslennikov, R. O.; Sevastyanov, A. G.; Ssorin, V. N.

    2013-01-01

    We consider the development of an integrated lens antenna for LAN radio communication systems operated in the 60 GHz frequency band. The antenna is an extended hemispherical silicon lens. On its flat surface, a microstrip antenna element is located. The use of silicon, which has a dielectric permittivity ɛ = 11.7, as the lens material ensures the maximum range of scanning angles for the minimum axial size of the lens. The approximate analytical formulas, which are used for initial calculations of the lens parameters, allow one to evaluate the basic parameters of the lens antenna integrated with the microstrip antenna element. For further optimizing the parameters of the lens and the antenna element, 3D simulation of the electromagnetic-field distribution was performed. Based on its results, we have developed and manufactured extended hemispherical silicon lenses, which had radii of 6 and 12 mm. The planar microstrip antenna element was manufactured by the low temperature co-fired ceramics (LTCC) technology. The results of simulation and experimental studies of the manufactured prototypes demonstrate that the developed lens antennas has directivities of 17.6 and 23.1 dBi for lenses with radii of 6 and 12 mm, respectively. In this case, the maximum beam deflection angle is achieved, which is equal to 55°, while the permissible decrease in the directivity is no more than 6 dBi compared with the case of a non-deflected beam. The obtained results show that the developed integrated lens antennas can find applications in high-speed radio communication systems operated in the millimeter-wave range.

  7. Mixed aggregate formation in gemini surfactant/1,2-dialkyl-sn-glycero-3-phosphoethanolamine systems.

    PubMed

    Akbar, Javed; Tavakoli, Naser; Marangoni, D Gerrard; Wettig, Shawn D

    2012-07-01

    An evaluation of the physical interactions between gemini surfactants, DNA, and 1,2-dialkyl-sn-glycero-3-phosphoethanolamine helper lipid is presented in this work. Complexation between gemini surfactants and DNA was first investigated using surface tensiometry where the surface tension profiles obtained were found to be consistent with those typically observed for mixed surfactant-polymer systems; that is, there is a synergistic lowering of the surface tension, followed by a first (CAC) and second (CMC) break point in the plot. The surfactant alkyl tail length was observed to exhibit a significant effect on the CAC, thus demonstrating the importance of hydrophobic interactions during complexation between gemini surfactants and DNA. The second study presented is an investigation of the mixing interactions between gemini surfactants and DOPE using Clint's, Rubingh's, and Motomura's theories for mixed micellar formation. The mixing interactions between the 16-3-16/16-7-16/16-12-16/16-7NH-16 gemini surfactants and DOPE were observed to be antagonistic, where the strength of antagonism was found to be dependent upon the gemini surfactant spacer group and the solution composition. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Rotationally Invariant Proof of Bell's Theorem Without Inequalities for 4k-Dimensional (k = 1,2,...) Systems

    NASA Astrophysics Data System (ADS)

    Liang, Lin-Mei; Li, Cheng-Zu

    2004-12-01

    We present rotationally invariant proof of Bell's theorem without inequalities for spin-(2N+1)/2 system (N = 2k-1, k = 1,2,3,4...) with only two particles, which is a generalization of Cabello's study [Phys. Rev. A 67 (2003) 032107].

  9. Compact and portable 100-GHz microresonator-based optical frequency comb generation system for dense wavelength division multiplexing fiber optic communication

    NASA Astrophysics Data System (ADS)

    Chuang, Yi-Chen; Liu, Tze-An; Ting, Wei-Jo; Chen, Hsin-Feng; Cheng, Yuh-Chuan; Hsu, Po-Er; Peng, Jin-Long

    2016-10-01

    A compact and portable microresonator-based optical frequency comb generation system was developed to provide an array of multiwavelength laser sources for dense wavelength division multiplexing (DWDM) fiber optic communication. The reported comb generation system was capable of producing comb lines after 7 km of travel without environmental control, indicating the effectiveness of the packaging. The comb spacing is about 98.3 GHz (i.e., ˜0.79 nm around 1553 nm), thus the comb line frequencies coincide nicely with 100-GHz DWDM channel frequencies, assuming the suggested channel bandwidth is 0.3 nm. The quality of selected comb lines was evaluated individually based on error vector magnitude (EVM) measurements along with RF spectrum measurements. An average EVM value observed is as low as 3.8%, close to typical EVM values of less than 3% used for fiber optic communication.

  10. Using a 1.2 GHz bandwidth reflective semiconductor optical amplifier with seeding light by 64-quadrature amplitude modulation orthogonal frequency division multiplexing modulation to achieve a 10-gbits/s upstream rate in long-reach passive optical network access

    NASA Astrophysics Data System (ADS)

    Yeh, Chien-Hung; Chen, Hsing-Yu; Chow, Chi-Wai; Wu, Yu-Fu

    2012-01-01

    We use a commercially available 1.2 GHz bandwidth reflective semiconductor optical amplifier (RSOA)--based optical network unit (ONU) to achieve 10-gbits/s upstream traffic for an optical orthogonal frequency division multiplexing (OFDM) long-reach passive optical network (LR-PON). This is the first time the 64--quadrature amplitude modulation (QAM) OFDM format has been applied to RSOA-ONU to achieve a 75 km fiber transmission length. In the proposed LR-PON, the upstream power penalty of 5.2 dB at the bit error rate of 3.8×10-3 is measured by using a 64-QAM OFDM modulation after the 75 km fiber transmission without dispersion compensation.

  11. Department of Defense (DOD) Automated Biometric Identification System (ABIS) Version 1.2: Initial Operational Test and Evaluation Report

    DTIC Science & Technology

    2015-05-01

    v1.2 did not experience any system aborts or failures exceeding 15 minutes duration during the 27 days of record test in the IOT&E; hence, the system...Desk operations. Although no system aborts were recorded during the 27 days of record test, 17 Essential Function Failures (EFF) required system...Failures that count against MTBF are termed system aborts . Essential Function Failures (EFF) that are at least 15 minutes in duration as termed system

  12. Feasibility study of microprocessor systems suitable for use in developing a real-time for the 4.75 GHz scatterometer

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A class of signal processors suitable for the reduction of radar scatterometer data in real time was developed. The systems were applied to the reduction of single polarized 13.3 GHz scatterometer data and provided a real time output of radar scattering coefficient as a function of incident angle. It was proposed that a system for processing of C band radar data be constructed to support scatterometer system currently under development. The establishment of a feasible design approach to the development of this processor system utilizing microprocessor technology was emphasized.

  13. Side mode suppression and dispersion compensation analysis of a 60 GHz radio-over-fibre system based on a gain switched laser

    NASA Astrophysics Data System (ADS)

    Martin, Eamonn; Barry, Liam

    2014-02-01

    The research and technical community have designated a band of 7 GHz between 57 and 64 GHz for short-range wireless communications. This paper utilizes a simple and cost effective technique for generating a 60 GHz millimeter-wave (mm-wave) signal using an optical comb source based on a gain-switched laser (GSL). This research investigates the effects unwanted comb lines have on the overall system performance with 2.5 Gb/s data transmission. To do this, a programmable optical filter is used to suppress the unwanted comb lines to varying levels. Bit-error rate (BER) measurements were carried out against received optical power to demonstrate the detrimental effects the unwanted comb lines have on the modulated mm-wave signal when not sufficiently suppressed. As chromatic dispersion is a limiting factor to the system's transmission distance, this work also investigates pre-compensation for dispersion utilizing the programmable group delay capabilities of the programmable optical filter, demonstrating the ability to extend the transmission distance by 12 km. All experimental results obtained are reinforced through simulation.

  14. 180-GHz Interferometric Imager

    NASA Technical Reports Server (NTRS)

    Kangaslahti, Pekka P.; Lim, Boon H.; O'Dwyer, Ian J.; Soria, Mary M.; Owen, Heather R.; Gaier, Todd C.; Lambrigtsen, Bjorn, H.; Tanner, Alan B.; Ruf, Christopher

    2011-01-01

    A 180-GHz interferometric imager uses compact receiver modules, combined high- and low-gain antennas, and ASIC (application specific integrated circuit) correlator technology, enabling continuous, all-weather observations of water vapor with 25-km resolution and 0.3-K noise in 15 minutes of observation for numerical weather forecasting and tropical storm prediction. The GeoSTAR-II prototype instrument is broken down into four major subsystems: the compact, low-noise receivers; sub-array modules; IF signal distribution; and the digitizer/correlator. Instead of the single row of antennas adopted in GeoSTAR, this version has four rows of antennas on a coarser grid. This dramatically improves the sensitivity in the desired field of view. The GeoSTAR-II instrument is a 48-element, synthetic, thinned aperture radiometer operating at 165-183 GHz. The instrument has compact receivers integrated into tiles of 16 elements in a 4x4 arrangement. These tiles become the building block of larger arrays. The tiles contain signal distribution for bias controls, IF signal, and local oscillator signals. The IF signals are digitized and correlated using an ASIC correlator to minimize power consumption. Previous synthetic aperture imagers have used comparatively large multichip modules, whereas this approach uses chip-scale modules mounted on circuit boards, which are in turn mounted on the distribution manifolds. This minimizes the number of connectors and reduces system mass. The use of ASIC technology in the digitizers and correlators leads to a power reduction close to an order of magnitude.

  15. Self-adjoint extensions of Coulomb systems in 1, 2 and 3 dimensions

    SciTech Connect

    Oliveira, Cesar R. de Verri, Alessandra A.

    2009-02-15

    We study the nonrelativistic quantum Coulomb hamiltonian (i.e., inverse of distance potential) in R{sup n}, n=1,2,3. We characterize their self-adjoint extensions and, in the unidimensional case, present a discussion of controversies in the literature, particularly the question of the permeability of the origin. Potentials given by fundamental solutions of Laplace equation are also briefly considered.

  16. CMMI Version 1.2 and Beyond Systems and Software Technology Conference

    DTIC Science & Technology

    2008-04-29

    more of the enterprise or potential partnering organizations — adapts model features to fit non-developmental efforts 11 CMMI Update: V1.2 and Beyond...competencies identified in the SLA BOK is underway, with a release planned for 2008 • Exam development will follow industry standards for assessment...34single level" approach • Improve acquisition organizations ’ understanding of the meaning of high maturity (levels 4 and 5) and equivalent staging

  17. Pumped helium system for cooling positron and electron traps to 1.2 K

    NASA Astrophysics Data System (ADS)

    Wrubel, J.; Gabrielse, G.; Kolthammer, W. S.; Larochelle, P.; McConnell, R.; Richerme, P.; Grzonka, D.; Oelert, W.; Sefzick, T.; Zielinski, M.; Borbely, J. S.; George, M. C.; Hessels, E. A.; Storry, C. H.; Weel, M.; Müllers, A.; Walz, J.; Speck, A.

    2011-06-01

    Extremely precise tests of fundamental particle symmetries should be possible via laser spectroscopy of trapped antihydrogen ( H¯) atoms. H¯ atoms that can be trapped must have an energy in temperature units that is below 0.5 K—the energy depth of the deepest magnetic traps that can currently be constructed with high currents and superconducting technology. The number of atoms in a Boltzmann distribution with energies lower than this trap depth depends sharply upon the temperature of the thermal distribution. For example, ten times more atoms with energies low enough to be trapped are in a thermal distribution at a temperature of 1.2 K than for a temperature of 4.2 K. To date, H¯ atoms have only been produced within traps whose electrode temperature is 4.2 K or higher. A lower temperature apparatus is desirable if usable numbers of atoms that can be trapped are to eventually be produced. This report is about the pumped helium apparatus that cooled the trap electrodes of an H¯ apparatus to 1.2 K for the first time. Significant apparatus challenges include the need to cool a 0.8 m stack of 37 trap electrodes separated by only a mm from the substantial mass of a 4.2 K Ioffe trap and the substantial mass of a 4.2 K solenoid. Access to the interior of the cold electrodes must be maintained for antiprotons, positrons, electrons and lasers.

  18. Low-energy spin dynamics of the s = 1/2 kagome system herbertsmithite.

    PubMed

    Nilsen, G J; de Vries, M A; Stewart, J R; Harrison, A; Rønnow, H M

    2013-03-13

    The low-energy (ε = ħω < 1 meV), low-temperature (T = 0.05 K) spin dynamics of the s = 1/2 kagome candidate herbertsmithite are probed in the presence of magnetic fields up to 2.5 T. The zero-field spectra reveal a very weak continuum of scattering at T = 10 K and a broad inelastic peak centred at ε(max) = 0.2 meV at lower temperatures, T < 1 K. The broad peak is found to be strongly damped, with a liquid-like structure factor implying correlations at length scales up to r = 6 Å. The field dependence of the peak appears to follow the Zeeman splitting of s = 1/2 excitations, consistent with the weakly split 'doublets' observed in low-temperature specific heat. A possible explanation of these observations is a short-range correlated state involving defect spins between the kagome planes and moments in the kagome layers.

  19. Propagation effects handbook for satellite systems design. A summary of propagation impairments on 10 to 100 GHz satellite links with techniques for system design

    NASA Technical Reports Server (NTRS)

    Ippolito, L. J.; Kaul, R. D.; Wallace, R. G.

    1983-01-01

    This Propagation Handbook provides satellite system engineers with a concise summary of the major propagation effects experienced on Earth-space paths in the 10 to 100 GHz frequency range. The dominant effect, attenuation due to rain, is dealt with in some detail, in terms of both experimental data from measurements made in the U.S. and Canada, and the mathematical and conceptual models devised to explain the data. In order to make the Handbook readily usable to many engineers, it has been arranged in two parts. Chapters 2-5 comprise the descriptive part. They deal in some detail with rain systems, rain and attenuation models, depolarization and experimental data. Chapters 6 and 7 make up the design part of the Handbook and may be used almost independently of the earlier chapters. In Chapter 6, the design techniques recommended for predicting propagation effects in Earth-space communications systems are presented. Chapter 7 addresses the questions of where in the system design process the effects of propagation should be considered, and what precautions should be taken when applying the propagation results.

  20. Integrated Safety Management System Phase I Verification for the Plutonium Finishing Plant (PFP) [VOL 1 & 2

    SciTech Connect

    SETH, S.S.

    2000-01-10

    U.S. Department of Energy (DOE) Policy 450.4, Safety Management System Policy commits to institutionalizing an Integrated Safety Management System (ISMS) throughout the DOE complex as a means of accomplishing its missions safely. DOE Acquisition Regulation 970.5204-2 requires that contractors manage and perform work in accordance with a documented safety management system.

  1. Effect on the immune system of mice exposed chronically to 50 Hz amplitude-modulated 2.45 GHz microwaves

    SciTech Connect

    Elekes, E.; Thuroczy, G.; Szabo, L.D.

    1996-12-01

    The effect of continuous (CW; 2.45 GHz carrier frequency) or amplitude-modulated (AM; 50 Hz square wave) microwave radiation on the immune response was tested. CW exposures (6 days, 3 h/day) induced elevations of the number of antibody-producing cells in the spleen of male Balb/c mice (+37%). AM microwave exposure induced elevation of the spleen index (+15%) and antibody-producing cell number (+55%) in the spleen of male mice. No changes were observed in female mice. It is concluded that both types of exposure conditions induced moderate elevation of antibody production only in male mice.

  2. Systemic angiopoietin-1/2 dysregulation following cardiopulmonary bypass in adults

    PubMed Central

    Charbonney, Emmanuel; Wilcox, Elizabeth; Shan, Yuexin; d'Empaire, Pablo Perez; Duggal, Abhijit; Rubenfeld, Gordon D; Liles, Conrad; Santos, Claudia Dos

    2017-01-01

    Aim: Vascular leakage following cardiopulmonary bypass contributes to morbidity. Angiopoietin-1 and -2 are biomarkers of endothelial dysfunction. Our aim was to characterize Ang-1 and -2 association with clinical characteristics and outcomes. Methods: Observational cohort study measuring Ang-1/-2 with a panel of cytokines in adults undergoing cardiopulmonary bypass. Results: Ang-2 levels increased immediately postop whereas Ang-1 levels decreased over time. No significant correlation was found with other inflammatory mediators. High correlation was found between the hospital length of stay and Ang-2 increase at 24 h (rho = 0.590; p < 0.0001). The predictors of Ang-2 increase were female gender, cross clamp time, transfusion of blood and absence of angiotensin-converting enzyme inhibitor as a pre-op medication. Conclusion: Angiopoietins can detect vascular leakage early and could impact patient's management to decrease length of stay after cardiac surgery. PMID:28344829

  3. The Electron-Optical System of a Gyrotron with an Operating Frequency of 263 GHz for Spectroscopic Research

    NASA Astrophysics Data System (ADS)

    Kuftin, A. N.; Manuilov, V. N.

    2016-07-01

    We describe specific features of modeling numerically the operation of magnetron-injection guns, which form high-quality helical electron beams in gyrotrons operated in the short-wave part of the millimeter-wave band (at a wavelength of 1 mm). As an example, we consider the gun of a gyrotron having an operating frequency of 263 GHz designed for spectroscopic research. It is shown that there are good reasons to perform calculations and optimization of the magnetroninjection un in two steps. At the first step, a simplest two-dimensional model can be used, which allows only for the influence of the field of the electrodes and the intrinsic space charge of the beam on the beam parameters. At the second, final stage one should allow for such factors as roughness of the emitting surface and thermal velocities of electrons. The electron distribution function in oscillatory velocities and the coefficient of electron reflection from the magnetic mirror should be calculated. It is demonstrated that the magnetron-injection gun, which is optimized by the method presented, is sufficiently universal and can be operated both at the first and second cyclotron-frequency harmonics. This opens up the possibility of developing gyrotrons for spectroscopy applications at frequencies of 263 and 526 GHz, respectively, which are required for biological and medical research.

  4. The Future RFI Environment Above 30 GHz

    NASA Astrophysics Data System (ADS)

    Clegg, Andrew W.

    1995-12-01

    Encompassing 30 - 300 GHz, the millimeter wave (mmW) band offers relief from spectrum crowding at lower frequencies, large available bandwidth, favorable propagation characteristics for certain applications, and relatively high directivity with small antennas. The FCC has recently proposed regulatory changes to foster commercial development of the mmW band. Impending actions include: Designating the 46.7-46.9 GHz and 76-77 GHz bands for unlicensed vehicular radar systems. Potentially tens of millions of vehicles will be equipped with radars to provide ``intelligent cruise control" capability and driver blind-spot warnings. Unwanted emissions from vehicular radar systems may produce harmful interference to passive systems operating in protected bands. Opening the 59-64 GHz band, in which propagation is limited to short distances due to high atmospheric attenuation, to general unlicensed devices. A likely application for this band is wireless local area computer networks. The neighboring bands of 58.2 - 59 and 64 - 65 GHz are allocated to the passive services. Changes still under consideration include: Opening the 116 - 117 GHz band, co-located with an existing passive allocation, for licensed (116 - 116.5 GHz) and general unlicensed (116.5 - 117 GHz) devices. The opening (for licensed and unlicensed services) of nearly 5 GHz of additional spectrum space which neighbors passive allocations and poses a potential interference problem from out-of-band emissions. The status of the FCC's actions concerning the mmW band will be updated. An attempt will be made to predict the RFI environment in the mmW band assuming the likely applications for each of the reallocated bands. Particular emphasis will be placed on the impact of the FCC's actions on current and planned remote sensing and radio astronomy operations.

  5. What Elements of the Inflammatory System Are Necessary for Epileptogenesis In Vitro?(1,2).

    PubMed

    Park, Kyung-Il; Dzhala, Volodymyr; Saponjian, Yero; Staley, Kevin J

    2015-01-01

    Epileptogenesis in vivo can be altered by manipulation of molecules such as cytokines and complement that subserve intercellular signaling in both the inflammatory and central nervous systems. Because of the dual roles of these signaling molecules, it has been difficult to precisely define the role of systemic inflammation in epileptogenesis. Organotypic hippocampal brain slices can be maintained in culture independently of the systemic inflammatory system, and the rapid course of epileptogenesis in these cultures supports the idea that inflammation is not necessary for epilepsy. However, this preparation still retains key cellular inflammatory mediators. Here, we found that rodent hippocampal organotypic slice cultures depleted of T lymphocytes and microglia developed epileptic activity at essentially the same rate and to similar degrees of severity as matched control slice cultures. These data support the idea that although the inflammatory system, neurons, and glia share key intercellular signaling molecules, neither systemic nor CNS-specific cellular elements of the immune and inflammatory systems are necessary components of epileptogenesis.

  6. Synthesis, optical and electrochemical study of bipolar heterocyclic systems, including 1,2,4-oxadiazole moiety

    NASA Astrophysics Data System (ADS)

    Selivanova, D. G.; Mayorova, O. A.; Gorbunov, A. A.; Vasyanin, A. N.; Dmitriev, M. V.; Shklyaeva, E. V.; Abashev, G. G.

    2016-12-01

    Two new 3,5-dihetarylsubstituted 1,2,4- oxadiazoles 8 a,b, including N-alkyl substituted carbazole and thiophene moieties, were synthesized as potential components of materials for organic electronics devices. Optical and electrochemical properties of all new compounds were investigated. On the basis of the experimental UV absorption data, the values of bandgap energies equal to 3.44 eV (8a) and 3.05 eV (8b) were determined. The values of their ionization potentials, HOMO levels (-5.62 eV for 8a, -5.46 eV - for 8b), as well as their electron affinity levels, LUMO levels (-2.2 eV for 8a, -2.4 eV - for 8b), were calculated from the results of electrochemical studies. The energy of the triplet excited states of 8 a,b was defined with the help of time-dependent density functional theory (TD-DFT), comprising 2.68 eV (8a) and 2.32 eV (8b), where the greatest value of this parameter was for the compound with a shorter conjugation chain.

  7. NASA Electronic Library System (NELS) database schema, version 1.2

    NASA Technical Reports Server (NTRS)

    Melebeck, Clovis J.

    1991-01-01

    The database tables used by NELS version 1.2 are discussed. To provide the current functional capability offered by NELS, nineteen tables were created with ORACLE. Each table lists the ORACLE table name and provides a brief description of the tables intended use or function. The following sections cover four basic categories of tables: NELS object classes, NELS collections, NELS objects, and NELS supplemental tables. Also included in each section is a definition and/or relationship of each field to other fields or tables. The primary key(s) for each table is indicated with a single asterisk (*), while foreign keys are indicated with double asterisks (**). The primary key(s) indicate the key(s) which uniquely identifies a record for that table. The foreign key(s) is used to identify additional information in other table(s) for that record. The two appendices are the command which is used to construct the ORACLE tables for NELS. Appendix A contains the commands which create the tables which are defined in the following sections. Appendix B contains the commands which build the indices for these tables.

  8. SPITZER OBSERVATIONS OF THE HH 1/2 SYSTEM: THE DISCOVERY OF THE COUNTERJET

    SciTech Connect

    Noriega-Crespo, A.; Raga, A. C.

    2012-05-10

    We present unpublished Spitzer IRAC observations of the HH 1/2 young stellar outflow processed with a high angular resolution deconvolution algorithm that produces subarcsecond ({approx}0.''6-0.''8) images. In the resulting mid-infrared images, the optically invisible counterjet is detected for the first time. The counterjet is approximately half as bright as the jet at 4.5 {mu}m (the IRAC band that best traces young stellar outflows) and has a length of {approx}10''. The NW optical jet itself can be followed back in the mid-IR to the position of the exciting VLA 1 source. An analysis of the IRAC colors indicates that the jet/counterjet emission is dominated by collisionally excited H{sub 2} pure rotational lines arising from a medium with a neutral hydrogen gas density of {approx}1000-2000 cm{sup -3} and a temperature of {approx} 1500 K. The observed jet/counterjet brightness asymmetry is consistent with an intrinsically symmetric outflow with extinction from a dense, circumstellar structure of {approx}6'' size (along the outflow axis), and with a mean visual extinction, A{sub V} {approx} 11 mag.

  9. Contactless Investigations of Yeast Cell Cultivation in the 7 GHz and 240 GHz Ranges

    NASA Astrophysics Data System (ADS)

    Wessel, J.; Schmalz, K.; Gastrock, G.; Cahill, B. P.; Meliani, C.

    2013-04-01

    Using a microfluidic system based on PTFE tubes, experimental results of contactless and label-free characterization techniques of yeast cell cultivation are presented. The PTFE tube has an inner diameter of 0.5 mm resulting in a sample volume of 2 μ1 for 1 cm sample length. Two approaches (at frequencies around 7 GHz and 240 GHz) are presented and compared in terms of sensitivity and applicability. These frequency bands are particularly interesting to gain information on the permittivity of yeast cells in Glucose solution. Measurements from 240 GHz to 300 GHz were conducted with a continuous wave spectrometer from Toptica. At 7 GHz band, measurements have been performed using a rat-race based characterizing system realized on a printed circuit board. The conducted experiments demonstrate that by selecting the phase as characterization parameter, the presented contactless and label-free techniques are suitable for cell cultivation monitoring in a PTFE pipe based microfluidic system.

  10. Federal Emergency Management Information system (FEMIS) data management guide. Version 1.2

    SciTech Connect

    Burnett, R.A.; Downing, T.R.; Gaustad, K.L.; Johnson, S.M.; Loveall, R.M.; Winters, C.

    1996-05-01

    The Federal Emergency Management Information System (FEMIS) is an emergency management planning and analysis tool that is being developed under the direction of the US Army Chemical and Biological Defense Command. The FEMIS Data Management Guide provides the background, as well as the operations and procedures needed to generate and maintain the data resources in the system. Database administrators, system administrators, and general users can use this guide to manage the data files and database that support the administrative, user-environment, database management, and operational capabilities of FEMIS. This document provides a description of the relational and spatial information present in FEMIS. It describes how the data was assembled, how it is loaded, and how it is managed while the system is in operation.

  11. A Reflection on the Fate of Chiral 1,2,4-Triazole Fungicides in Biological Systems

    EPA Science Inventory

    In biological systems, stereoisomers of chiral compounds can exhibit significantly different pharmacokinetics (absorption, distribution, metabolism, and elimination) and pharmacodynamics (physiological effects). Pharmacokinetic processes (i.e., what the body does to the chemical)...

  12. A Reflection on the Fate of Chiral 1,2,4-Triazole Fungicides in Biological Systems

    EPA Science Inventory

    In biological systems, stereoisomers of chiral compounds can exhibit significantly different pharmacokinetics (absorption, distribution, metabolism, and elimination) and pharmacodynamics (physiological effects). Pharmacokinetic processes (i.e., what the body does to the chemical)...

  13. Coastal Storm Surge Analysis: Computational System, Report 2: Intermediate Submission No. 1.2

    DTIC Science & Technology

    2011-03-01

    Figure 2.15 Data sources utilized to define mesh bathymetry and topography. Nodes shaded in green utilized DEM elevations, those in magenta used the...complete end-to-end modeling system, with all required forcing inputs, for updating the floodplain levels for coastal and inland watershed communities ...Geographic Information System (GIS) tools to facilitate archiving, distribution, and analysis of the various storm surge data products Under the

  14. Integrated radwaste treatment system lessons learned from 2{1/2} years of operation

    SciTech Connect

    Baker, M.N.; Fussner, R.J.

    1997-05-01

    The Integrated Radwaste Treatment System (IRTS) at the West Valley Demonstration Project (WVDP) is a pretreatment scheme to reduce the amount of salts in the high-level radioactive waste (vitrification) stream. Following removal of cesium-137 (Cs-137) by ion-exchange in the Supernatant Treatment System (STS), the radioactive waste liquid is volume-reduced by evaporation. Trace amounts of Cs-137 in the resulting distillate are removed by ion-exchange, then the distillate is discharged to the existing plant water treatment system. The concentrated product, 37 to 41 percent solids by weight, is encapsulated in cement producing a stable, low-level waste form. The Integrated Radwaste Treatment System (IRTS) operated in this mode from May 1988 through November 1990, decontaminating 450,000 gallons of high-level waste liquid; evaporating and encapsulating the resulting concentrates into 10,393 71-gallon square drums. A number of process changes and variations from the original operating plan were required to increase the system flow rate and minimize waste volumes. This report provides a summary of work performed to operate the IRTS, including system descriptions, process highlights, and lessons learned.

  15. Liquid Effluent Monitoring Information System test plans release 1.2

    SciTech Connect

    Adams, R.T.

    1994-10-11

    The Liquid Effluent Monitoring Information System (LEMIS) is being developed as the organized information repository facility in support of the liquid effluent monitoring requirements of the Tri-Party Agreement. It is necessary to provide an automated repository into which the results from liquid effluent sampling will be placed. This repository must provide for effective retention, review, and retrieval of selected sample data by authorized persons and organizations. This System Architecture document is the aggregation of the DMR P+ methodology project management deliverables. Together they represent a description of the project and its plan through four Releases, corresponding to the definition and prioritization of requirements defined by the user.

  16. Hydrogen Macro System Model User Guide, Version 1.2.1

    SciTech Connect

    Ruth, M.; Diakov, V.; Sa, T.; Goldsby, M.; Genung, K.; Hoseley, R.; Smith, A.; Yuzugullu, E.

    2009-07-01

    The Hydrogen Macro System Model (MSM) is a simulation tool that links existing and emerging hydrogen-related models to perform rapid, cross-cutting analysis. It allows analysis of the economics, primary energy-source requirements, and emissions of hydrogen production and delivery pathways.

  17. Amplitude Linearizers for PEP-II 1.2 MW Klystrons and LLRF Systems

    SciTech Connect

    Van Winkle, D.; Browne, J.; Fox, J.D.; Mastorides, T.; Rivetta, C.; Teytelman, D.; /SLAC

    2006-07-18

    The PEP-II B-factory has aggressive current increases planned for luminosity through 2008. At 2.2A (HER) on 4A (LER) currents, we estimate that longitudinal growth rates will be comparable to the damping rates currently achieved in the existing low level RF and longitudinal feedback systems. Prior to having a good non-linear time domain model [1] it was postulated that klystron small signal gain non-linearity may be contributing to measured longitudinal growth rates being higher than linearly predicted growth rates. Five prototype klystron amplitude modulation linearizers have been developed to explore improved linearity in the LLRF system. The linearizers operate at 476 MHz with 15 dB dynamic range and 1 MHz linear control bandwidth. Results from lab measurements and high current beam tests are presented. Future development plans, conclusions from beam testing and ideas for future use of this linearization technique are presented.

  18. Automated Procurement System (APS): Project management plan (DS-03), version 1.2

    NASA Technical Reports Server (NTRS)

    Murphy, Diane R.

    1994-01-01

    The National Aeronautics and Space Administration (NASA) Marshall Space Flight Center (MSFC) is implementing an Automated Procurement System (APS) to streamline its business activities that are used to procure goods and services. This Project Management Plan (PMP) is the governing document throughout the implementation process and is identified as the APS Project Management Plan (DS-03). At this point in time, the project plan includes the schedules and tasks necessary to proceed through implementation. Since the basis of APS is an existing COTS system, the implementation process is revised from the standard SDLC. The purpose of the PMP is to provide the framework for the implementation process. It discusses the roles and responsibilities of the NASA project staff, the functions to be performed by the APS Development Contractor (PAI), and the support required of the NASA computer support contractor (CSC). To be successful, these three organizations must work together as a team, working towards the goals established in this Project Plan. The Project Plan includes a description of the proposed system, describes the work to be done, establishes a schedule of deliverables, and discusses the major standards and procedures to be followed.

  19. Systems Biology Graphical Notation: Activity Flow language Level 1 Version 1.2.

    PubMed

    Mi, Huaiyu; Schreiber, Falk; Moodie, Stuart; Czauderna, Tobias; Demir, Emek; Haw, Robin; Luna, Augustin; Le Novère, Nicolas; Sorokin, Anatoly; Villéger, Alice

    2015-09-04

    The Systems Biological Graphical Notation (SBGN) is an international community effort for standardized graphical representations of biological pathways and networks. The goal of SBGN is to provide unambiguous pathway and network maps for readers with different scientific backgrounds as well as to support efficient and accurate exchange of biological knowledge between different research communities, industry, and other players in systems biology. Three SBGN languages, Process Description (PD), Entity Relationship (ER) and Activity Flow (AF), allow for the representation of different aspects of biological and biochemical systems at different levels of detail. The SBGN Activity Flow language represents the influences of activities among various entities within a network. Unlike SBGN PD and ER that focus on the entities and their relationships with others, SBGN AF puts the emphasis on the functions (or activities) performed by the entities, and their effects to the functions of the same or other entities. The nodes (elements) describe the biological activities of the entities, such as protein kinase activity, binding activity or receptor activity, which can be easily mapped to Gene Ontology molecular function terms. The edges (connections) provide descriptions of relationships (or influences) between the activities, e.g., positive influence and negative influence. Among all three languages of SBGN, AF is the closest to signaling pathways in biological literature and textbooks, but its well-defined semantics offer a superior precision in expressing biological knowledge.

  20. Bacterial Cyclic β-(1,2)-Glucan Acts in Systemic Suppression of Plant Immune Responses[W

    PubMed Central

    Rigano, Luciano Ariel; Payette, Caroline; Brouillard, Geneviève; Marano, Maria Rosa; Abramowicz, Laura; Torres, Pablo Sebastián; Yun, Maximina; Castagnaro, Atilio Pedro; Oirdi, Mohamed El; Dufour, Vanessa; Malamud, Florencia; Dow, John Maxwell; Bouarab, Kamal; Vojnov, Adrian Alberto

    2007-01-01

    Although cyclic glucans have been shown to be important for a number of symbiotic and pathogenic bacterium–plant interactions, their precise roles are unclear. Here, we examined the role of cyclic β-(1,2)-glucan in the virulence of the black rot pathogen Xanthomonas campestris pv campestris (Xcc). Disruption of the Xcc nodule development B (ndvB) gene, which encodes a glycosyltransferase required for cyclic glucan synthesis, generated a mutant that failed to synthesize extracellular cyclic β-(1,2)-glucan and was compromised in virulence in the model plants Arabidopsis thaliana and Nicotiana benthamiana. Infection of the mutant bacterium in N. benthamiana was associated with enhanced callose deposition and earlier expression of the PATHOGENESIS-RELATED1 (PR-1) gene. Application of purified cyclic β-(1,2)-glucan prior to inoculation of the ndvB mutant suppressed the accumulation of callose deposition and the expression of PR-1 in N. benthamiana and restored virulence in both N. benthamiana and Arabidopsis plants. These effects were seen when cyclic glucan and bacteria were applied either to the same or to different leaves. Cyclic β-(1,2)-glucan–induced systemic suppression was associated with the transport of the molecule throughout the plant. Systemic suppression is a novel counterdefensive strategy that may facilitate pathogen spread in plants and may have important implications for the understanding of plant–pathogen coevolution and for the development of phytoprotection measures. PMID:17601826

  1. Graphene based GHz detectors

    NASA Astrophysics Data System (ADS)

    Boyd, Anthony K.; El Fatimy, Abdel; Barbara, Paola; Nath, Anindya; Campbell, Paul M.; Myers-Ward, Rachael; Daniels, Kevin; Gaskill, D. Kurt

    Graphene demonstrates great promise as a detector over a wide spectral range especially in the GHz range. This is because absorption is enhanced due to the Drude contribution. In the GHz range there are viable detection mechanisms for graphene devices. With this in mind, two types of GHz detectors are fabricated on epitaxial graphene using a lift off resist-based clean lithography process to produce low contact resistance. Both device types use asymmetry for detection, consistent with recent thoughts of the photothermoelectric effect (PTE) mechanism. The first is an antenna coupled device. It utilizes two dissimilar contact metals and the work function difference produces the asymmetry. The other device is a field effect transistor constructed with an asymmetric top gate that creates a PN junction and facilitates tuning the photovoltaic response. The response of both device types, tested from 100GHz to 170GHz, are reported. This work was sponsored by the U.S. Office of Naval Research (Award Number N000141310865).

  2. Systemic chemotherapy with FOLFOX in metastatic grade 1/2 neuroendocrine cancer

    PubMed Central

    Faure, Marjorie; Niccoli, Patricia; Autret, Aurelie; Cavaglione, Gerard; Mineur, Laurent; Raoul, Jean-Luc

    2017-01-01

    Neuroendocrine tumors (NETs) comprise a heterogeneous group of malignancies with various clinical presentations and evolution. NETs are often diagnosed at a late stage, when they are already metastatic. Treatment is currently based on traditional chemotherapies, such as streptozocin, with serious side effects. The favorable toxicity profile of the combination of 5-fluorouracil with oxaliplatin, together with its significant antitumor activity in several gastrointestinal malignancies, led to the evaluation of its efficacy and tolerability in patients with advanced grade 1/2 (G1/G2) NETs. The endpoints of the study were tumor response (according to the Response Evaluation Criteria in Solid Tumors 1.1), overall survival (OS), progression-free survival (PFS) and symptom improvement. From January, 2013 to January, 2015, during our Regional Multidisciplinary Tumor Board dedicated to NETs (RENATEN network), FOLFOX was recommended for the treatment of metastatic NETs as first-line therapy or after failure of other therapies. The inclusion criteria were metastatic, well-differentiated G1/G2 NETs, progressing within the last 3 months. Cases with previous antitumor therapy were allowed. The patients received modified FOLFOX-6 and were assessed every 3 months by computed tomography or magnetic resonance imaging examinations. A total of 31 patients were included. The median follow-up was 20 months [95% confidence interval (CI): 15–27]. Nine patients (29%) exhibited a partial response, and 13 (41%) achieved stable disease; the disease control rate was 70%. A total of 9 patients exhibited disease progression. The control rate was 78% for pancreatic and 65% for extrapancreatic NETs. The median OS was not reached; the 1- and 2-year OS rates were 89 and 70%, respectively (Fig. 1). No significant difference in OS was observed between the <5 and 5–20% Ki-67 subgroups (P=0.41) (Fig. 2A) or according to primary tumor location (P=0.71) (Fig. 2B). The median PFS was 14.1 months (95

  3. User`s guide to the META-Net economic modeling system. Version 1.2

    SciTech Connect

    Lamont, A.

    1994-11-24

    In a market economy demands for commodities are met through various technologies and resources. Markets select the technologies and resources to meet these demands based on their costs. Over time, the competitiveness of different technologies can change due to the exhaustion of resources they depend on, the introduction of newer, more efficient technologies, or even shifts in user demands. As this happens, the structure of the economy changes. The Market Equilibrium and Technology Assessment Network Modelling System, META{center_dot}Net, has been developed for building and solving multi-period equilibrium models to analyze the shifts in the energy system that may occur as new technologies are introduced and resources are exhausted. META{center_dot}Net allows a user to build and solve complex economic models. It models` a market economy as a network of nodes representing resources, conversion processes, markets, and end-use demands. Commodities flow through this network from resources, through conversion processes and market, to the end-users. META{center_dot}Net then finds the multiperiod equilibrium prices and quantities. The solution includes the prices and quantities demanded for each commodity along with the capacity additions (and retirements) for each conversion process, and the trajectories of resource extraction. Although the changes in the economy are largely driven by consumers` behavior and the costs of technologies and resources, they are also affected by various government policies. These can include constraints on prices and quantities, and various taxes and constraints on environmental emissions. META{center_dot}Net can incorporate many of these mechanisms and evaluate their potential impact on the development of the economic system.

  4. Thermal transport study of S = 1/2 kagome frustrated system Volborthite

    NASA Astrophysics Data System (ADS)

    Watanabe, Daiki; Yamashita, Minoru; Shimozawa, Masaaki; Suzuki, Yoshitaka; Ishikawa, Hajime; Hiroi, Zenji; Matsuda, Yuji

    2015-03-01

    The nature of spin liquid states of 2D frustrated magnetic systems has been discussed over decades. Recently, some candidate materials of 2D quantum spin liquid have been reported from the absence of long range order in low temperatures. However, the elementary excitations which characterize the ground state have yet to be observed. It is suggested that thermal Hall measurement is a powerful probe to identify the elementary excitations of 2D quantum spin liquids. Here we report the results of thermal-transport measurements of Volborthite (Cu3V2O7(OH)2 . 2H2O) which possesses the 2D kagome planes. We observed double anomalies in the thermal conductivity around 1K. These anomalies correspond magnetic orderings reported by the NMR measurements and the specific heat measurements. We will also talk about our thermal Hall measurements above the ordering temperature.

  5. Collective uncertainty in partially polarized and partially decohered spin-(1)/(2) systems

    NASA Astrophysics Data System (ADS)

    Baragiola, Ben Q.; Chase, Bradley A.; Geremia, Jm

    2010-03-01

    It has become common practice to model large spin ensembles as an effective pseudospin with total angular momentum J=Nj, where j is the spin per particle. Such approaches (at least implicitly) restrict the quantum state of the ensemble to the so-called symmetric Hilbert space. Here, we argue that symmetric states are not generally well preserved under the type of decoherence typical of experiments involving large clouds of atoms or ions. In particular, symmetric states are rapidly degraded under models of decoherence that act identically but locally on the different members of the ensemble. Using an approach [Phys. Rev. A 78, 052101 (2008)] that is not limited to the symmetric Hilbert space, we explore potential pitfalls in the design and interpretation of experiments on spin-squeezing and collective atomic phenomena when the properties of the symmetric states are extended to systems where they do not apply.

  6. Orbit-spectrum sharing between the fixed-satellite and broadcasting-satellite services with applications to 12 GHz domestic systems

    NASA Technical Reports Server (NTRS)

    Reinhart, E. E.

    1974-01-01

    A systematic, tutorial analysis of the general problem of orbit-spectrum sharing among inhomogeneous satellite system is presented. Emphasis is placed on extrapolating and applying the available data on rain attenuation and on reconciling differences in the results of various measurements of the subjective effects of interference on television picture quality. An analytic method is presented for determining the approximate values of the intersatellite spacings required to keep mutual interference levels within prescribed limits when many dissimilar satellites share the orbit. A computer model was developed for assessing the interference compatibility of arbitrary configurations of large numbers of geostationary satellite systems. It is concluded that the band from 11.7 c GHz can be shared effectively by broadcasting-satellite and fixed-satellite systems. Recommendations for future study are included.

  7. Screened spin-1 and -1/2 Kondo effect in a triangular quantum dot system with interdot Coulomb repulsion

    NASA Astrophysics Data System (ADS)

    Xiong, Yong-Chen; Wang, Wei-Zhong; Luo, Shi-Jun; Yang, Jun-Tao; Huang, Hai-Ming

    2017-03-01

    By means of the numerical renormalization group (NRG) technique, we study the low temperature transport property and the phase transition for a triangular triple quantum dot system, including two centered dots (dot 1 and 2) and one side dot (dot 3). We focus on the effect of interdot repulsion V between two centered dots in a wide range of the interdot hopping tij (i,j = 1,2,3). When the hoppings between the centered dot and the side dot are symmetric, i.e., t13 = t23, and that between two centered dots t12 is small, two centered dots form a spin triplet when V is absent, and a totally screened spin-1 Kondo effect is observed. In this case, one has a spin 1 that is partially screened by the leads as in the usual spin-1 Kondo model, and the remaining spin 1/2 degree of freedom forms a singlet with the side dot. As V is large enough, one of the centered dots is singly occupied, while the other one is empty. The spin-1/2 Kondo effect is found when t13 is small. For large t12, two centered dots form a spin singlet when V = 0, leading to zero conductance. As V is large enough, the spin-1/2 Kondo effect is recovered in the case of small t13. For asymmetric t13≠t23 and small t12, a crossover is found as V increases in comparison with a first order quantum phase transition for the symmetric case. In the regime of large V, the spin-1/2 Kondo effect could also be found when both t13 and t23 are small. We demonstrate the present model is similar to the side-coupled double dot system in some appropriate regimes, and it appears as a possible realization of side-controllable molecular electronics and spintronics devices.

  8. Photon polarization version of the GHz-Mermin Gedanken

    NASA Technical Reports Server (NTRS)

    Kiess, Thomas E.

    1992-01-01

    We have defined a photon polarization analog of the Greenberger, Horne, and Zeilinger (GHZ) experiment that was initially proposed for spin-1/2 quanta. Analogs of the ket states and Pauli spin matrix operators are presented.

  9. Intelligent Engine Systems Work Element 1.2: Malfunction and Operator Error Reduction

    NASA Technical Reports Server (NTRS)

    Wiseman, Matthew

    2005-01-01

    Jet engines, although highly reliable and safe, do experience malfunctions that cause flight delays, passenger stress, and in some cases, in conjunction with inappropriate crew response, contribute to airplane accidents. On rare occasions, the anomalous engine behavior is not recognized until it is too late for the pilots to do anything to prevent or mitigate the resulting engine malfunction causing in-flight shutdowns (IFSDs), aborted takeoffs (ATOs), or loss of thrust control (LOTC). In some cases, the crew response to a myriad of external stimuli and existing training procedures is the source of the problem mentioned above. The problem is the reduction of jet engine malfunctions (IFSDs, ATOs, and LOTC) and inappropriate crew response (PSM+ICR) through the use of evolving and advanced technologies. The solution is to develop the overall system health maintenance architecture, detection and accommodation technologies, processes, and enhanced crew interfaces that would enable a significant reduction in IFSDs, ATOs, and LOTC. This program defines requirements and proposes a preliminary design concept of an architecture that enables the realization of the solution.

  10. Aerodynamic characteristics of the National Launch System (NLS) 1 1/2 stage launch vehicle

    NASA Technical Reports Server (NTRS)

    Springer, A. M.; Pokora, D. C.

    1994-01-01

    The National Aeronautics and Space Administration (NASA) is studying ways of assuring more reliable and cost effective means to space. One launch system studied was the NLS which included the l l/2 stage vehicle. This document encompasses the aerodynamic characteristics of the 1 l/2 stage vehicle. To support the detailed configuration definition two wind tunnel tests were conducted in the NASA Marshall Space Flight Center's 14x14-Inch Trisonic Wind Tunnel during 1992. The tests were a static stability and a pressure test, each utilizing 0.004 scale models. The static stability test resulted in the forces and moments acting on the vehicle. The aerodynamics for the reference configuration with and without feedlines and an evaluation of three proposed engine shroud configurations were also determined. The pressure test resulted in pressure distributions over the reference vehicle with and without feedlines including the reference engine shrouds. These pressure distributions were integrated and balanced to the static stability coefficients resulting in distributed aerodynamic loads on the vehicle. The wind tunnel tests covered a Mach range of 0.60 to 4.96. These ascent flight aerodynamic characteristics provide the basis for trajectory and performance analysis, loads determination, and guidance and control evaluation.

  11. Renormalized theory of the two-dimensional S = 1 / 2 dilute spin-wave systems at low temperatures

    NASA Astrophysics Data System (ADS)

    Chang, Chih-Chun; Lin, Lee

    2009-01-01

    Due to strong fluctuations, conventional approaches to handling repulsive spin-1/2 spin-waves in three dimensions do not work in low dimensions at temperature T ≠ 0 . We have constructed a renormalized theory for the two-dimensional spin-1/2 anisotropic quantum Heisenberg model by means of exact mappings between spin-1/2 systems and their corresponding hard-core Bose-Hubbard systems. With the t-matrix method, hard-core Bose-Hubbard systems can be effectively described by the corresponding soft-core Bose-Hubbard Hamiltonians at low energy. The method of running coupling constant in field theory is used to fix the infrared divergence due to long wavelength fluctuations in low dimensions at T ≠ 0 . Our results agree well with previous analytical and numerical works. The method dealing with infinities used by others in 3D is a special case of our renormalization scheme. Our approach works in both two and three dimensions at T = 0 and T > 0 . We think that our renormalization scheme is a more general and systematic approach in condensed matter physics.

  12. Further Characterization of 394-GHz Gyrotron FU CW GII with Additional PID Control System for 600-MHz DNP-SSNMR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ueda, Keisuke; Matsuki, Yoh; Fujiwara, Toshimichi; Tatematsu, Yoshinori; Ogawa, Isamu; Idehara, Toshitaka

    2016-09-01

    A 394-GHz gyrotron, FU CW GII, has been designed at the University of Fukui, Japan, for dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) experiments at 600-MHz 1H resonant frequency. After installation at the Institute for Protein Research (IPR), Osaka University, Japan, a PID feedback control system was equipped to regulate the electron gun heater current for stabilization of the electron beam current, which ultimately achieved stabilization of output power when operating in continuous wave (CW) mode. During exploration to further optimize operating conditions, a continuous tuning bandwidth of approximately 1 GHz was observed by varying the operating voltage at a fixed magnetic field. In the frequency range required for positive DNP enhancement, the output power was improved by increasing the magnetic field and the operating voltage from their initial operational settings. In addition, fine tuning of output frequency by varying the cavity cooling water temperature was demonstrated. These operating conditions and ancillary enhancements are expected to contribute to further enhancement of SSNMR signal.

  13. Distinct Neurochemical Profiles of Spinocerebellar Ataxias 1, 2, 6, and Cerebellar Multiple System Atrophy

    PubMed Central

    Öz, Gülin; Iltis, Isabelle; Hutter, Diane; Thomas, William; Bushara, Khalaf O.; Gomez, Christopher M.

    2011-01-01

    Hereditary and sporadic neurodegenerative ataxias are movement disorders that affect the cerebellum. Robust and objective biomarkers are critical for treatment trials of ataxias. In addition, such biomarkers may help discriminate between ataxia subtypes because these diseases display substantial overlap in clinical presentation and conventional MRI. Profiles of 10–13 neurochemical concentrations obtained in vivo by high field proton magnetic resonance spectroscopy (1H MRS) can potentially provide ataxia-type specific biomarkers. We compared cerebellar and brainstem neurochemical profiles measured at 4 T from 26 patients with spinocerebellar ataxias (SCA1, N=9; SCA2, N=7; SCA6, N=5) or cerebellar multiple system atrophy (MSA-C, N=5) and 15 age-matched healthy controls. The Scale for the Assessment and Rating of Ataxia (SARA) was used to assess disease severity. The patterns of neurochemical alterations relative to controls differed between ataxia types. Myo-inositol levels in the vermis, myo-inositol, total N-acetylaspartate, total creatine, glutamate, glutamine in the cerebellar hemispheres and myo-inositol, total N-acetylaspartate, glutamate in the pons were significantly different between patient groups (Bonferroni corrected p<0.05). The best MRS predictors were selected by a tree classification procedure and lead to 89% accurate classification of all subjects while the SARA scores overlapped considerably between patient groups. Therefore, this study demonstrated multiple neurochemical alterations in SCAs and MSA-C relative to controls and the potential for these neurochemical levels to differentiate ataxia types. Studies with higher numbers of patients and other ataxias are warranted to further investigate the clinical utility of neurochemical levels as measured by high-field MRS as ataxia biomarkers. PMID:20838948

  14. Process Test Evaluation Report Waste Retrieval Sluicing System Emissions Collection (Phase 1 - 2 and 3)

    SciTech Connect

    PARKMAN, D.B.

    1999-12-29

    During sluicing of the first batch of sludge from tank 241-C-106 on November 18, 1998, an unexpected high concentration of volatile organic compounds was measured in the 296-C-006 ventilation stack. Eleven workers reported irritation related symptoms and were sent to Hanford Environmental Health Foundation (HEHF) and Kadlec Hospital for medical evaluations. No residual health effects were reported. As a result of the unexpectedly high concentrations of volatile organic compounds encountered during this November sluicing event, a phased process test designed to characterize the emission constituents was conducted on December 16, 1998, March 7, 1999, and March 28, 1999. The primary focus of this evaluation was to obtain samples of the 296-C-006 ventilation stack effluent and surrounding areas at elevated levels of volatile organic compounds initiated by sluicing. Characterization of the emission constituents was necessary to establish appropriate procedural and administrative exposure controls for continued sluicing. Additionally, this information would be used to evaluate the need for engineered equipment to mitigate any further potential chemical stack emissions. This evaluation confirms that the following actions taken during Phase I, Phase II, and Phase III of the Waste Retrieval Sluicing System Emissions Collection Process Test were conservative and appropriate for continued sluicing: Implement stack limit of 500 ppm volatile organic compounds, with lower administrative limits; Ensure worker involvement through enhanced planning; Continue using the existing fenced boundary location; Continue using pressure demand fresh air respiratory protection inside the C-Farm as recommended by Industrial Hygiene; Continue using the existing respiratory protection/ take cover requirements outside the C-Farm boundary as recommended by Industrial Hygiene; Continue using existing anti-contamination clothing; Minimize the number of workers exposed to emissions; Maintain the

  15. Gene/protein expression of CAPN1/2-CAST system members is associated with ERK1/2 kinases activity as well as progression and clinical outcome in human laryngeal cancer.

    PubMed

    Starska, Katarzyna; Forma, Ewa; Jóźwiak, Paweł; Lewy-Trenda, Iwona; Danilewicz, Marian; Stasikowska-Kanicka, Olga; Skóra, Michał; Kolary, Katarzyna; Miazga, Jakub; Krześlak, Anna; Bryś, Magdalena

    2016-10-01

    Recent evidence indicates the involvement of calpains (CAPNs), a family of cysteine proteases, in cancer development and progression, as well as the insufficient response to cancer therapies. The contribution of CAPNs and regulatory calpastatin (CAST) and ERK1/2 kinases to aggressiveness, disease course, and outcome in laryngeal cancer remains elusive. This study was aimed to evaluate the CAPN1/2-CAST-ERK1/2 enzyme system mRNA/protein level and to investigate whether they can promote the dynamic of tumor growth and prognosis. The mRNA expression of marker genes was determined in 106 laryngeal cancer (SCLC) cases and 73 non-cancerous adjacent mucosa (NCLM) controls using quantitative real-time PCR. The level of corresponding proteins was analyzed by Western Blot. SLUG expression, as indicator of pathological advancement was determined using IHC staining. Significant increases of CAPN1/2-CAST-ERK1/2 levels of mRNA/protein were noted in SCLC compared to NCLM (p < 0.05). As a result, a higher level of CAPN1 and ERK1 genes was related to larger tumor size, more aggressive and deeper growth according to TFG scale and SLUG level (p < 0.05). There were also relationships of CAPN1/2 and ERK1 with incidences of local/nodal recurrences (p < 0.05). An inverse association for CAPN1/2, CAST, and ERK1/2 transcripts was determined with regard to overall survival (p < 0.05). In addition, a higher CAPN1 and phospho-ERK1 protein level was related to higher grade and stage (p < 0.05) and was found to promote worse prognosis. This is the first study to show that activity of CAPN1/2- CAST-ERK1/2 axis may be an indicator of tumor phenotype and unfavorable outcome in SCLC.

  16. Generation of a three-qudit GHZ state with diamond defect spins

    NASA Astrophysics Data System (ADS)

    Hebbache, M.

    2016-07-01

    Diamond defect spins have emerged as potential qudits (d-dimensional quantum bit) in quantum information and quantum computing. A new scheme is proposed for realizing entangled states of GHZ (Greenberger-Horne-Zeilinger) class in a 3-qudit solid-state register. The qudits are the electron spin-1 carried by the negatively charged nitrogen-vacancy color center (NV-1) in diamond and the nuclear spin-\\frac{1}{2} of two carbon-13 impurities in the first neighbour shell. Multipartite entanglements between qudits are obtained by bringing the spin system in the vicinity of a level anticrossing. The degree of entanglement between all three qudits is quantified rigorously. GHZ and GHZ-like entangled states have applications in quantum communication and computation protocols.

  17. Cryogenic 160-GHz MMIC Heterodyne Receiver Module

    NASA Technical Reports Server (NTRS)

    Samoska, Lorene A.; Soria, Mary M.; Owen, Heather R.; Dawson, Douglas E.; Kangaslahti, Pekka P.; Gaier, Todd C.; Voll, Patricia; Lau, Judy; Sieth, Matt; Church, Sarah

    2011-01-01

    A cryogenic 160-GHz MMIC heterodyne receiver module has demonstrated a system noise temperature of 100 K or less at 166 GHz. This module builds upon work previously described in Development of a 150-GHz MMIC Module Prototype for Large-Scale CMB Radiation (NPO-47664), NASA Tech Briefs, Vol. 35, No. 8 (August 2011), p. 27. In the original module, the local oscillator signal was saturating the MMIC low-noise amplifiers (LNAs) with power. In order to suppress the local oscillator signal from reaching the MMIC LNAs, the W-band (75 110 GHz) signal had to be filtered out before reaching 140 170 GHz. A bandpass filter was developed to cover 120 170 GHz, using microstrip parallel-coupled lines to achieve the desired filter bandwidth, and ensure that the unwanted W-band local oscillator signal would be sufficiently suppressed. With the new bandpass filter, the entire receiver can work over the 140 180-GHz band, with a minimum system noise temperature of 460 K at 166 GHz. The module was tested cryogenically at 20 K ambient temperature, and it was found that the receiver had a noise temperature of 100 K over an 8-GHz bandwidth. The receiver module now includes a microstrip bandpass filter, which was designed to have a 3-dB bandwidth of approximately 120-170 GHz. The filter was fabricated on a 3-mil-thick alumina substrate. The filter design was based on a W-band filter design made at JPL and used in the QUIET (Q/U Imaging ExperimenT) radiometer modules. The W-band filter was scaled for a new center frequency of 150 GHz, and the microstrip segments were changed accordingly. Also, to decrease the bandwidth of the resulting scaled design, the center gaps between the microstrip lines were increased (by four micrometers in length) compared to the gaps near the edges. The use of the 150-GHz bandpass filter has enabled the receiver module to function well at room temperature. The system noise temperature was measured to be less than 600 K (at room temperature) from 154 to 168 GHz

  18. A calibration system for the Green Bank Telescope 4mm receiver: On-telescope, RFI-free calibration for 68-92 GHz observations

    NASA Astrophysics Data System (ADS)

    Watts, Galen

    2012-11-01

    Calibration for spectral line observations covering 68-92 GHz on the Green Bank Telescope uses a different calibration scheme than lower frequency receivers. In addition and extremely important is that any calibration scheme must not generate radio frequency interference (RFI) to other experiments ongoing at the Green Bank Observatory. An asynchronous logic network interfaces between the telescope control system, a brushless AC motor and three bit position encoding to place or remove reflectors, absorber or a quarter wave plate in the beam of the feeds to enable observers to calibrate their data during observations or configure the receiver for Very Long Baseline Interferometer network observations. This system is free of RFI that schemes utilizing more commonly available technology create.

  19. Fractional Quantum Hall Effect at ν = 1 / 2 in Hole Systems Confined to GaAs Wide Quantum Wells

    NASA Astrophysics Data System (ADS)

    Hasdemir, Sukret; Liu, Yang; Graninger, Aurelius; Shayegan, Mansour; Pfeiffer, Loren; West, Ken; Baldwin, Kirk; Winkler, Roland

    2014-03-01

    We observe fractional quantum Hall effect (FQHE) at the even-denominator Landau level filling factor ν = 1 / 2 in two-dimensional hole systems confined to GaAs quantum wells of width 30 to 50 nm and having bilayer-like charge distributions. The ν = 1 / 2 FQHE is stable when the charge distribution is symmetric and only in a range of intermediate densities, qualitatively similar to what is seen in two-dimensional electron systems confined to approximately twice wider GaAs quantum wells. Despite the complexity of the hole Landau level structure, originating from the coexistence and mixing of the heavy- and light-hole states, we find the hole ν = 1 / 2 FQHE to be consistent with a two-component, Halperin-Laughlin (Ψ331) state. We acknowledge support through the DOE BES (DE-FG02-00-ER45841) for measurements, and the Gordon and Betty Moore Foundation (Grant GBMF2719), Keck Foundation, and the NSF (DMR-0904117, DMR-1305691 and MRSEC DMR-0819860) for sample fabrication. Work at Arg.

  20. Preliminary Bremstrahlung Measurements on VENUS at 18 and 28 GHz

    SciTech Connect

    Lyneis, C.M.; Leitner, D.

    2005-03-15

    The bremstrahlung produced by the VENUS ECR ion source at 18 GHz and 28 GHz in the axial direction has been measured with a germanium detector. The bremstrahlung spectrum goes out beyond 1 MeV at 28 GHz and this complicates analysis of the data and the design of the collimators and detection system. Preliminary spectra and the geometry of the detection system will be described.

  1. A 10 GHz bandwidth, single transient, digitized oscilloscope with 20 GHz capability

    SciTech Connect

    Hudson, C.L.; Kocimski, S.M.; Spector, J.; Thomas, J.B.; Woodstra, R.R.

    1993-12-31

    EG&G/EM has developed an oscilloscope with a {minus}3 dB bandwidth greater than 10 GHz. Its rolloff characteristics are such that single-transient data greater than 20 GHz may be captured. A demountable CCD camera records the oscilloscope trace and is provided with PC-compatible capture and data processing software. The capabilities of the oscilloscope, camera, and its processing software are described and examples of the system`s performance is shown.

  2. Transverse magnetization transfer under planar mixing conditions in spin systems consisting of three coupled spins 1/2.

    PubMed

    Luy, Burkhard; Glaser, Steffen J

    2003-10-01

    Polarization transfer under planar mixing conditions is a widely used tool in modern NMR-experiments. In the case of two coupled spins 1/2 or a chain of three or more spins 1/2 with only nearest neighbor couplings, it is only possible to transfer a single magnetization component (longitudinal magnetization in the principle axis system of the planar coupling tensors). However, if all couplings in a three-spin system are non-zero, it turns out that all magnetization components can be efficiently transferred even under strictly planar mixing conditions. In this article a detailed theoretical analysis is presented based on analytical transverse coherence transfer functions and on the underlying commutator algebra. In addition, transverse magnetization transfer is demonstrated experimentally. The results show that in highly coupled spin systems, as for example in the case of partially aligned samples with many residual dipolar couplings, special care has to be taken to avoid phase distortions if planar mixing steps are used.

  3. Synthesis and antiproliferative activity of the ring system [1,2]oxazolo[4,5-g]indole.

    PubMed

    Barraja, Paola; Caracausi, Libero; Diana, Patrizia; Spanò, Virginia; Montalbano, Alessandra; Carbone, Anna; Parrino, Barbara; Cirrincione, Girolamo

    2012-11-01

    Brand new ring: A series of 27 derivatives of the new ring system [1,2]oxazolo[4,5-g]indole were conveniently prepared and tested at the NCI for antiproliferative studies. Several of them showed good inhibitory activity toward all tested cell lines, reaching GI50 values generally at the micromolar and sub-micromolar levels and in some cases at nanomolar concentrations. The mean GI50 values, calculated on the full panel, were in the range 0.25-7.08 μM.

  4. OSIRISv1.2: A named entity recognition system for sequence variants of genes in biomedical literature

    PubMed Central

    Furlong, Laura I; Dach, Holger; Hofmann-Apitius, Martin; Sanz, Ferran

    2008-01-01

    Background Single Nucleotide Polymorphisms, among other type of sequence variants, constitute key elements in genetic epidemiology and pharmacogenomics. While sequence data about genetic variation is found at databases such as dbSNP, clues about the functional and phenotypic consequences of the variations are generally found in biomedical literature. The identification of the relevant documents and the extraction of the information from them are hampered by the large size of literature databases and the lack of widely accepted standard notation for biomedical entities. Thus, automatic systems for the identification of citations of allelic variants of genes in biomedical texts are required. Results Our group has previously reported the development of OSIRIS, a system aimed at the retrieval of literature about allelic variants of genes . Here we describe the development of a new version of OSIRIS (OSIRISv1.2, ) which incorporates a new entity recognition module and is built on top of a local mirror of the MEDLINE collection and HgenetInfoDB: a database that collects data on human gene sequence variations. The new entity recognition module is based on a pattern-based search algorithm for the identification of variation terms in the texts and their mapping to dbSNP identifiers. The performance of OSIRISv1.2 was evaluated on a manually annotated corpus, resulting in 99% precision, 82% recall, and an F-score of 0.89. As an example, the application of the system for collecting literature citations for the allelic variants of genes related to the diseases intracranial aneurysm and breast cancer is presented. Conclusion OSIRISv1.2 can be used to link literature references to dbSNP database entries with high accuracy, and therefore is suitable for collecting current knowledge on gene sequence variations and supporting the functional annotation of variation databases. The application of OSIRISv1.2 in combination with controlled vocabularies like MeSH provides a way to

  5. The design of an active support control system for a thin 1.2m primary mirror

    NASA Astrophysics Data System (ADS)

    Liu, Rong; Li, Xiaojin; Liu, Haitao; Wang, Hongqiao

    2014-09-01

    Active support system is a low-frequency wavefront error correction system, which is often used to correct the mirror deformation resulting from gravity, temperature, wind load, manufacture, installation and other factors. In addition, the active support technology can improve the efficiency of grinding and polishing by adjusting the surface shape in the process of manufacturing large mirrors. This article describes the design of an active support control system for a thin 1.2m primary mirror. The support system consists of 37 axial pneumatic actuators. And in order to change the shape of thin primary mirror we need to precisely control the 37 pneumatic actuators. These 37 pneumatic actuators are divided into six regions. Each region is designed with a control circuit board to realize force closed-loop control for the pneumatic actuators, and all control panels are connected to the PC by CAN bus. The control panels have to support: receive commands from the host PC; control the actuators; periodically return result of control. The whole control system is composed by hardware and control algorithm and communication program.

  6. Radiometric Measurements of Powerline Cables at 94 GHz

    DTIC Science & Technology

    2001-02-01

    ARMY RESEARCH LABORATORY Radiometric Measurements of Powerline Cables at 94 GHz David A. Wikner and Thomas J. Pizzillo ARL-TR-837 February 2001...MD 20783-1197 ARL-TR-837 February 2001 Radiometric Measurements of Powerline Cables at 94 GHz David A. Wikner and Thomas J. Pizzillo Sensors and...collision avoidance system," Proc. SPIE 3088 (April 1997), pp 57-63. 5. D. Wikner and T. Pizzillo, "Measurement of nadir and near-nadir 94-GHz

  7. Ba3Cr2O8, a new non-Cu based quantum s=1/2 spin singlet system

    NASA Astrophysics Data System (ADS)

    Kofu, Maiko

    2009-03-01

    Field-induced condensation of magnons has been experimentally observed in several weakly coupled quantum (s = 1/2) dimer systems that are based on Cu^2+ ions, such as TlCuCl3 and BaCuSi2O6, and it has been adequately described by the Bose-Einstein condensation (BEC) theory. However, the robustness of such descriptions can only be truly evaluated with investigation into complementary materials, in particular materials that are based on non-Cu^2+ ions. Recently, a new spin dimer system, Ba3Cr2O8 has been found, where Cr^5+ (s=1/2) ion with the unusual 5+ electronic valence forms quantum dimers along the c-axis and a frustrating triangular lattice in the ab-plane. Using elastic and inelastic neutron scattering measurements on single crystals and a powder sample, we have characterized the magnetic interactions to show that Ba3Cr2O8 is indeed an excellent model system of weakly coupled quantum dimers [1]. We have also investigated the field-induced condensation of magnons in this compound, using specific heat, bulk magnetization, and elastic neutron scattering measurements under an external magnetic field. The experimental results and comparison to the theories will be discussed. *This work is in collaboration with J.-H. Kim, S. Ji, S.-H. Lee (University of Virginia), H. Ueda, Y. Ueda (ISSP, University of Tokyo), H. Nojiri (IMR, Tohoku University), B. Lake, K. Rule (Helmholtz Centre Berlin). [4pt] [1] M. Kofu et al., cond-mat/0809.5069 (2008).

  8. Experimental Investigation of Plume-Induced Flow Separation on the National Launch System 1 1/2-Stage Launch Vehicle

    NASA Technical Reports Server (NTRS)

    Springer, A.

    1994-01-01

    An experimental investigation of plume-induced flow separation on the National Launch System (NLS) 1 1/2-stage launch vehicle was done. This investigation resulted from concerns raised about the flow separation that was encountered on the Saturn 5. A large similarity exists between configurations and nominal trajectories. The study involved the use of solid plume simulators to simulate the base pressure encountered by the vehicle due to engine exhaust plumes at predetermined critical Mach numbers based on Saturn 5 flight plume effects. The solid plume was varied in location, resulting in a parametric study of base pressure effects on flow separation. In addition to the parametric study of arbitrary plume locations, the base pressure resulting from the nominal trajectory was tested. This analysis was accomplished through two wind tunnel tests run at NASA Marshall Space Flight Center's 14 x 14-inch Trisonic Wind Tunnel during 1992. The two tests were a static stability and a pressure test each using a 0.004-scale NLS 1 1/2-stage model. This study verified that flow separation is present at Mach 2.74 and 3.48 for predicted flight base pressures at nominal or higher levels. The flow separation at the predicted base pressure is only minor and should not be of great concern. It is not of the magnitude of the flow separation that was experienced on the Saturn 5. If the base pressure exceeds these nominal conditions, the flow separation can drastically increase, and is of concern.

  9. Possible solution to the riddle of HD 82943 multiplanet system: the three-planet resonance 1:2:5?

    NASA Astrophysics Data System (ADS)

    Baluev, Roman V.; Beaugé, Cristian

    2014-03-01

    We carry out a new analysis of the published radial velocity data for the planet-hosting star HD 82943. We include the recent Keck/HIRES measurements as well as the aged but much more numerous CORALIE data. We find that the CORALIE radial velocity measurements are polluted by a systematic annual variation which affected the robustness of many previous results. We show that after purging this variation, the residuals still contain a clear signature of an additional ˜1100 d periodicity. The latter variation leaves significant hints in all three independent radial velocity subsets that we analysed: the CORALIE data, the Keck data acquired prior to a hardware upgrade and the Keck data taken after the upgrade. We mainly treat this variation as a signature of a third planet in the system, although we cannot rule out other interpretations, such as long-term stellar activity. We find it easy to naturally obtain a stable three-planet radial velocity fit close to the three-planet mean-motion resonance 1:2:5, with the two main planets (those in the 1:2 resonance) in an aligned apsidal corotation. The dynamical status of the third planet is still uncertain: it may reside in as well as slightly out of the 5:2 resonance. We obtain the value of about 1075 d for its orbital period and ˜0.3MJup for its minimum mass, while the eccentric parameters are uncertain.

  10. GHz repetition rate tabletop X-band photoinjector for free-electron laser applications

    SciTech Connect

    Le Sage, G.P.; Fochs, S.N.; Feng, H.X.C.

    1995-12-31

    A 1-1/2 cell {pi}-mode X-bend (8.568 GHz) photoinjector system capable of producing trains of up to one hundred, 1 nC, 1ps, 5 MeV, {epsilon}{sub n} < 2.5 {pi} mm-mrad photoelectron bunches, at a micropulse repetition rate of 1-10 Hz, is currently under development at LLNL, in the UC Davis DAS coherent millimeter-wave group. The system is powered by a 20 MW, 8.568 GHz SLAC development klystron. The system also uses a Cs{sub 2}Te (Cesium Telluride) photocathode which has a quantum efficiency > 5% in the UV (210 nm). The compact UV laser system is composed of a synchronously modelocked AlGaAs semiconductor laser oscillator which produces pulses with a duration of 250 fs and 100 pJ energy at 830 nm, at a repetion rate of 2.142 GHz with less 400 is jitter, a 5 GHz bandwidth Lithium Niobate Mach-Zender fiber modulator, an 8-pass, 10{sup 6} gain, TiAl{sub 2}O{sub 3} (Titanium:Sapphire) chirped pulse amplifier, and 2 BBO frequency doublers in series to quadruple the laser frequency into the UV (207 nm).

  11. Low-temperature ordered phases of the spin-1/2 XXZ chain system Cs2CoCl4

    NASA Astrophysics Data System (ADS)

    Breunig, O.; Garst, M.; Rosch, A.; Sela, E.; Buldmann, B.; Becker, P.; Bohatý, L.; Müller, R.; Lorenz, T.

    2015-01-01

    In this study the magnetic order of the spin-1/2 XXZ chain system Cs2CoCl4 in a temperature range from 50 mK to 0.5 K and in applied magnetic fields up to 3.5 T is investigated by high-resolution measurements of the thermal expansion and the specific heat. Applying magnetic fields along a or c suppresses TN completely at about 2.1 T. In addition, we find an adjacent intermediate phase before the magnetization saturates close to 2.5 T. For magnetic fields applied along b , a surprisingly rich phase diagram arises. Two additional transitions are observed at critical fields μ0HS F 1≃0.25 T and μ0HS F 2≃0.7 T , which we propose to arise from a two-stage spin-flop transition.

  12. [Measurement and study report as a part of the control system for human safety and health protection against electromagnetic fields and electromagnetic radiation (0 Hz-300 GHz)].

    PubMed

    Aniołczyk, Halina

    2007-01-01

    The National Control System for safety and health protection against electromagnetic fields (EMF) and electromagnetic radiation (EMR) (0 Hz-300 GHz) is constantly analyzed in view of Directive 2004/40/EC. Reports on the effects of investments (at the designing stage or at the stage of looking for their localization) on the environment and measurement and study reports on the objects already existing or being put into operation are important elements of this system. These documents should meet both national and European Union's legislation requirements. The overriding goal of the control system is safety and health protection of humans against electromagnetic fields in the environment and in occupational settings. The author pays a particular attention to provisions made in directives issued by relevant ministers and to Polish standards, which should be documented in measurement and study reports published by the accredited laboratories and relating to the problems of human safety and health protection. Similar requirements are valid for the Reports. Therefore, along with measurement outcomes, the reports should include data on the EMF exposure classification at work-posts and the assessment of occupational risk resulting from EMF exposure or at least thorough data facilitating such a classification.

  13. Feasibility demonstration of booster cross-over system for 3 1/2 inch SRB/MLP frangible nut system

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Recent testing of the SRB/MLP Frangible Nut System (SOS Part Number 114850-9/Boosters P/N 114848-3) at NASA indicated a need to reduce the function time between boosters (2) within a single frangible nut. These boosters are initiated separately by electrical impulse(s). Coupling the output of each detonator with an explosive cross-over would reduce the function time between boosters (independent of electrical impulse) while providing additional redundancy to the system. The objectives of this program were to: provide an explosive cross-over between boosters, reduce function time between boosters to less than one (1) millisecond within a given nut, reduce cost of boosters, be compatible with the existing frangible nut system, and meet requirements of USBI Spec's (nut 10SPC-0030, booster 10SPC-0031).

  14. Mobile measurement setup according to IEC 62220-1-2 for DQE determination on digital mammography systems

    NASA Astrophysics Data System (ADS)

    Greiter, Matthias B.; Hoeschen, Christoph

    2010-04-01

    The international standard IEC 62220-1-2 defines the measurement procedure for determination of the detective quantum efficiency (DQE) of digital x-ray imaging devices used in mammography. A mobile setup complying to this standard and adaptable to most current systems was constructed in the Helmholtz Zentrum München to allow for an objective technical comparison of current full field digital mammography units employed in mammography screening in Germany. This article demonstrates the setup's capabilities with a focus on the measurement uncertainties of all quantities contributing to DQE measurements. Evaluation of uncertainties encompasses results from measurements on a Sectra Microdose Mammography in clinical use, as well as on a prototype of a Fujifilm Amulet system at various radiation qualities. Both systems have a high spatial resolution of 50 μm × 50 μm. The modulation transfer function (MTF), noise power spectrum (NPS) and DQE of the Sectra MDM are presented in comparison to results previously published by other authors.

  15. Improving RF Transmit Power and Received Signal Strength in 2.4 GHz ZigBee Based Active RFID System with Embedded Method

    NASA Astrophysics Data System (ADS)

    Po'ad, F. A.; Ismail, W.; Jusoh, J. F.

    2017-08-01

    This paper describes the experiments and analysis conducted on 2.4 GHz embedded active Radio Frequency Identification (RFID) - Wireless Sensor Network (WSN) based system that has been developed for the purposes of location tracking and monitoring in indoor and outdoor environments. Several experiments are conducted to test the effectiveness and performance of the developed system and two of them is by measuring the Radio Frequency (RF) transmitting power and Received Signal Strength (RSS) to prove that the embedded active RFID tag is capable to generate higher transmit power during data transmission and able to provide better RSS reading compared to standalone RFID tag. Experiments are carried out on two RFID tags which are active RFID tag embedded with GPS and GSM (ER2G); and standalone RFID tag communicating with the same active RFID reader. The developed ER2G contributes 12.26 % transmit power and 6.47 % RSS reading higher than standalone RFID tag. The results conclude that the ER2G gives better performance compared to standalone RFID tag and can be used as guidelines for future design improvements.

  16. IDH1/2 gene hotspot mutations in central nervous system tumours: analysis of 922 Chinese patients.

    PubMed

    Chen, Ni; Yu, Tianpin; Gong, Jing; Nie, Ling; Chen, Xueqin; Zhang, Mengni; Xu, Miao; Tan, Junya; Su, Zhengzheng; Zhong, Jinjing; Zhou, Qiao

    2016-12-01

    Mutations of isocitrate dehydrogenase 1 (IDH1) or 2 (IDH2) genes have been identified as early molecular events in the development of astrocytomas and oligodendrogliomas. Data regarding the status and prevalence of IDH1/2 mutations in Chinese patients are limited. Herein we report our data from West China Hospital, a major Chinese medical centre. IDH1(R132H) mutation was analysed by immunohistochemistry with the mutation-specific IDH1(R132H) antibody in 1011 patients, including 922 central nervous system (CNS) tumours and 89 non-neoplastic CNS lesions, and PCR-based direct sequencing of IDH1/2 gene mutation in 570 of these samples. Correlation with clinicopathological features and immunohistochemical expression of p53, EGFR, PTEN and Ki-67 was examined. Our data showed that IDH1/2 mutation was present in oligodendrogliomas, anaplastic oligodendrogliomas, diffuse or anaplastic astrocytomas, and glioblastomas, with decreasing frequency, but not in other types of CNS tumours or non-neoplastic lesions examined. IDH1(R132) mutation was most frequent in oligodendrogliomas (57/62, 91.9%), with IDH1(R132H) mutation as the most frequent mutation form. Only one case for each of the rare mutations (R132C, R132G, R132L, and R132S) was identified in the 570 samples analysed by sequencing. Younger age, low expression of p53 and low Ki-67 index were significantly correlated with IDH1 mutation status (p=0.000). All tumours with IDH1(R132) mutations were supratentorial, with frontal lobe as the most frequent site for IDH-mutated gliomas. Only three IDH2(R172) mutation cases were detected in this series. Univariate survival analysis in 459 glioma patients with diffusely infiltrating gliomas showed that IDH1 mutations as well as the more classical prognosticators (age, WHO grade, p53 and Ki-67 index) were of prognostic significance. Multivariate analysis by Cox proportional hazard regression model demonstrated that lack of IDH1 mutation was an independent prognostic factor for both

  17. A 30 GHz monolithic receive module

    NASA Technical Reports Server (NTRS)

    Mondal, J.; Contolatis, T.; Geddes, J.; Bauhahn, P.; Sokolov, V.

    1990-01-01

    The technical achievements and deliveries made during the duration of the program to develop a 30 GHz monolithic receive module for communication feed array applications and to deliver submodules and 30 GHz monolithic receive modules for experimental evaluation are discussed. Key requirements include an overall receive module noise figure of 5 dB, a 30 dB RF-to-RF gain with six levels of intermediate gain control, a five bit phase shifter, and a maximum power consumption of 250 mW. In addition, the monolithic receive module design addresses a cost goal of less than one thousand dollars (1980 dollars) per module in unit buys of 5,000 or more, and a mechanical configuration that is applicable to a spaceborne phase array system. An additional task for the development and delivery of 32 GHz phase shifter integrated circuit (IC) for deep space communication is also described.

  18. Characteristics associated with genetic counseling referral and BRCA1/2 testing among women in a large integrated health system.

    PubMed

    Bellcross, Cecelia A; Peipins, Lucy A; McCarty, Frances A; Rodriguez, Juan L; Hawkins, Nikki A; Hensley Alford, Sharon; Leadbetter, Steven

    2015-01-01

    Evidence shows underutilization of cancer genetics services. To explore the reasons behind this underutilization, this study evaluated characteristics of women who were referred for genetic counseling and/or had undergone BRCA1/2 testing. An ovarian cancer risk perception study stratified 16,720 eligible women from the Henry Ford Health System into average-, elevated-, and high-risk groups based on family history. We randomly selected 3,307 subjects and interviewed 2,524 of them (76.3% response rate). Among the average-, elevated-, and high-risk groups, 2.3, 10.1, and 20.2%, respectively, reported genetic counseling referrals, and 0.8, 3.3, and 9.5%, respectively, reported having undergone BRCA testing. Personal breast cancer history, high risk, and perceived ovarian cancer risk were associated with both referral and testing. Discussion of family history with a doctor predicted counseling referral, whereas belief that family history influenced risk was the strongest BRCA testing predictor. Women perceiving their cancer risk as much higher than other women their age were twice as likely (95% confidence interval: 2.0-9.6) to report genetic counseling referral. In a health system with ready access to cancer genetic counseling and BRCA testing, women who were at high risk underutilized these services. There were strong associations between perceived ovarian cancer risk and genetic counseling referral, and between a belief that family history influenced risk and BRCA testing.

  19. Propagation handbook, frequencies above 10 GHz

    NASA Technical Reports Server (NTRS)

    Ippolito, Louis J.

    1988-01-01

    The progress and accomplishments in the developmet of the Fourth Edition of the NASA Propagation Effects Handbook for Satellite Systems Design, for frequencies 10 to 100 GHz, NASA Reference Publication 1082(04), dated May 1988, prepared by Westighouse Electric Corporation for the Jet Propulsion Laboratory are discussed.

  20. 44/20 GHz Ground Terminal.

    DTIC Science & Technology

    1987-08-01

    contract was awarded to Andrew Antenna Co., Whitby , Ontario to design and construct the (44/20) GHz feed system. The design (Fig. 1) also included the...Receive 1.5 max. Power Rating (10 - 100) watts Axial ratios VSWR, and primary patterns (Appendix A) were measured at the Whitby Plant and supplied

  1. Environmental assessment for the Satellite Power System (SPS): studies of honey bees exposed to 2. 45 GHz continuous-wave electromagnetic energy

    SciTech Connect

    Gary, N E; Westerdahl, B B

    1980-12-01

    A system for small animal exposure was developed for treating honey bees, Apis mellifera L., in brood and adult stages, with 2.45 GHz continuous wave microwaves at selected power densities and exposure times. Post-treatment brood development was normal and teratological effects were not detected at exposures of 3 to 50 mw/cm/sup 2/ for 30 minutes. Post-treatment survival, longevity, orientation, navigation, and memory of adult bees were also normal after exposures of 3 to 50 mw/cm/sup 2/ for 30 minutes. Post-treatment longevity of confined bees in the laboratory was normal after exposures of 3 to 50 mw/cm/sup 2/ for 24 hours. Thermoregulation of brood nest, foraging activity, brood rearing, and social interaction were not affected by chronic exposure to 1 mw/cm/sup 2/ during 28 days. In dynamic behavioral bioassays the frequency of entry and duration of activity of unrestrained, foraging adult bees was identical in microwave-exposed (5 to 40 mw/cm/sup 2/) areas versus control areas.

  2. An SIS Waveguide heterodyne Reciever for 600 GHz - 635 GHz

    NASA Technical Reports Server (NTRS)

    Salez, Morvan; Febvre, Pascal; McGrath, William R.; Bumble, Bruce; LeDuc, Henry G.

    1994-01-01

    A waveguide SIS heterodyne receiver using a Nb/A10xNb junction has been built for astronomical observations of molecular tranitions in the frequency range 600GHz - 635GHZ, and has been successfully used at the Caltech Submillimeter Observatory (CSO).

  3. Synthesis of 1,2,4-Triazines and the Triazinoisoquinolinedione DEF Ring System of Noelaquinone†‡

    PubMed Central

    Cao, Liming; Maciejewski, John P.; Elzner, Stephan; Amantini, David

    2012-01-01

    The intramolecular Staudinger aza-Wittig reaction is used for a general synthesis of 1,2,5,6-tetrahydro-1,2,4-triazines, a structural motif reported for the natural product noelaquinone. The DEF moiety of noelaquinone was obtained in 13 steps and 2% overall yield, and the structure of the synthetic product was confirmed by x-ray analysis. PMID:22473572

  4. Klystron Linearizer for Use with 1.2 MW 476 MHz Klystrons in PEP-II RF Systems

    SciTech Connect

    Fox, J.; Mastorides, T.; Teytelman, D.; Van Winkle, D.; Zhou, Y.; Gallo, A.; /Frascati

    2005-06-15

    The direct and comb loop feedback around the RF cavities in PEP-II is critical in reducing longitudinal instabilities driven by the cavity impedance. The non-linear 1.2 MW klystron is in the signal path for these feedback loops. As a result, the effective small-signal gain of the klystron at 85% saturation reduces the impedance control by factors of 5 to 20 as compared to a linear power amplifier. A klystron linearizer circuit has been developed which operates in series with the power amplifier and acts to equalize the small and large signal gains through the combination. The technique must implement a 1 MHz linear control bandwidth over roughly 15 dB of RF signal level variation. The dynamics of this system is operating point dependent, and the channel must have dynamic gain compensation to keep the linearity compensation loop stable over changes in operating point. The design of this non-linear signal processing channel (incorporating RF and DSP techniques) and measured results from full-power klystron testing are presented.

  5. Fiber-wireless transmission system of 108  Gb/sdata over 80 km fiber and 2×2multiple-input multiple-output wireless links at 100 GHz W-band frequency.

    PubMed

    Li, Xinying; Dong, Ze; Yu, Jianjun; Chi, Nan; Shao, Yufeng; Chang, G K

    2012-12-15

    We experimentally demonstrate a seamlessly integrated fiber-wireless system that delivers a 108  Gb/s signal through 80 km fiber and 1 m wireless transport over free space at 100 GHz adopting polarization-division-multiplexing quadrature-phase-shift-keying (PDM-QPSK) modulation and heterodyning coherent detection. The X- and Y-polarization components of the optical PDM-QPSK baseband signal are simultaneously upconverted to 100 GHz wireless carrier by optical polarization-diversity heterodyne beating, and then independently transmitted and received by two pairs of transmitter and receiver antennas, which form a 2×2 multiple-input multiple-output wireless link. At the wireless receiver, two-stage downconversion is performed firstly in the analog domain based on balanced mixer and sinusoidal radio frequency signal, and then in the digital domain based on digital signal processing (DSP). Polarization demultiplexing is realized by the constant modulus algorithm in the DSP part at the receiver. The bit-error ratio for the 108  Gb/s PDM-QPSK signal is less than the pre-forward-error-correction threshold of 3.8×10(-3) after both 1 m wireless delivery at 100 GHz and 80 km single-mode fiber-28 transmission. To our knowledge, this is the first demonstration to realize 100  Gb/s signal delivery through both fiber and wireless links at 100 GHz.

  6. Spacecraft in switch matrix for wide band service applicatons in 30/20 GHz communications satellite systems

    NASA Technical Reports Server (NTRS)

    Cory, B. J.

    1982-01-01

    Bandwidth, switching speed, off-state isolation, and reliability over a ten-year mission were factors in determining the optimum available technology for satellite communications switching in 1982. A proof of concept model for a 20 x 20 coupled crossbar switch matrix designed with FET devices for microwave switching and with high speed CMOS LIS for switch crosspoint addressing was fabricated and tested. Results show the design is feasible for application in a multichannel SS-TDMA communications system. Expandibility can readily be achieved with this design. A conceptual design study for a 100 x 100 switch matrix utilizing a coupled crossbar architecture implemented with a monolithic microwave integrated circuits revealed technology needs for high capacity switch matrices.

  7. Development of a 20/30 GHz Receiving Station for Propagation Experiments with L-SAT.

    DTIC Science & Technology

    1984-10-25

    EXPERIMENTS WITH L-SAT ~ Angel Cardama Universidad Politdcnica de Barcelona Escuela Tdcnica Superior • de Ingenieros de Telecomunicaci6n 08034 - Barcelona...reflexion and transmission modes. The operating options available in our laboratory, 2 - 20 GHz automa tic vector system, 36 GHz manual scalar for...to 20 GHz, manual scalar ceflection and transmission benches at 36 GHz and vector reflection system at the same frequency, will be com- pleted with a

  8. Cost-effective 33-Gbps intensity modulation direct detection multi-band OFDM LR-PON system employing a 10-GHz-based transceiver

    NASA Astrophysics Data System (ADS)

    Hsu, Dar-Zu; Wei, Chia-Chien; Chen, Hsing-Yu; Li, Wei-Yuan; Chen, Jyehong

    2011-08-01

    We develop a dynamic multi-band OFDM subcarrier allocation scheme to fully utilize the available bandwidth under the restriction of dispersion- and chirp-related power fading. The experimental results successfully demonstrate an intensity-modulation-direct-detection 34.78-Gbps OFDM signal transmissions over 100-km long-reach (LR) passive-optical networks (PONs) based on a cost-effective 10-GHz EAM and a 10-GHz PIN. Considering 0--100-km transmission bandwidth of a 10-GHz EAM, the narrowest bandwidth is theoretically evaluated to occur at ~40 km, instead of 100 km. Consequently, the performances of 20--100-km PONs are experimentally investigated, and at least 33-Gbps capacity is achieved to support LR-PONs of all possible 20--100-km radii.

  9. 14/12-GHz-band satellite communication services

    NASA Astrophysics Data System (ADS)

    Hayashi, Kunihiro; Nagaki, Kiyoaki; Mori, Yasuo

    1990-01-01

    Three new systems for integrated TV-relay services have been developed: Satellite Video Comunication Service (SVCS) and Satellite Digital Communication Service (SDCS), with Japan's 14/12-GHz-band commercial communication satellites. These systems have been in commercial use since May 1989. Usually SVCS and SDCS have been provided using Ka-band (30/20 GHz-band) of CS-2 and Cs-3. This paper provides an overview of the design, the performance, and the systems of the new 14/12-GHz-band satellite communication services.

  10. 177-207 GHz Radiometer Front End: Single Sideband Measurements

    NASA Technical Reports Server (NTRS)

    Galin, I.; Schnitzer, C. A.; Dengler, R. J.; Quintero, O.

    1999-01-01

    Twenty years of progress in 200 GHz receivers for spaceborne remote sensing has yielded a 180-220 GHz technology with maturing characteristics, as evident by increasing availability of relevant hardware, paralleled by further refinement in receiver performance requirements at this spectrum band. The 177-207 GHz superheterodyne receiver, for the Earth observing system (EOS) microwave limb sounder (MLS), effectively illustrates such technology developments. This MLS receiver simultaneously detects six different signals, located at sidebands below and above its 191.95 GHZ local-oscillator (LO). The paper describes the MLS 177-207 GHz receiver front-end (RFE), and provides measured data for its lower and upper sidebands. Sideband ratio data is provided as a function of IF frequency, at different LO power drive, and for variation in the ambient temperature.

  11. BaV3O8: A possible Majumdar-Ghosh system with S = (1)/(2)

    NASA Astrophysics Data System (ADS)

    Chakrabarty, T.; Mahajan, A. V.; Gippius, A. A.; Tkachev, A. V.; Büttgen, N.; Kraetschmer, W.

    2013-07-01

    BaV3O8 contains magnetic V4+(S=1/2) ions and also nonmagnetic V5+(S=0) ions. The V4+ ions are arranged in a coupled Majumdar-Ghosh chainlike network. A Curie-Weiss fit of our magnetic susceptibility χ(T) data in the temperature region of 80-300 K yields a Curie constant C=0.39 cm3K/mole V4+ and an antiferromagnetic Weiss temperature θ=-26K. The χ(T) curve shows a broad maximum at T≃25 K indicative of short-range order (SRO) and an anomaly corresponding to long-range order (LRO) at TN˜6 K. The value of the “frustration parameter” (f=|θ/TN|˜5) suggests that the system is moderately frustrated. Above the LRO temperature, the experimental magnetic susceptibility data match well with the coupled Majumdar-Ghosh (or Jnn-Jnnn Heisenberg) chain model with the ratio of the nnn (next-nearest neighbor) to nn (nearest neighbor) magnetic coupling α=2 and Jnnn/kB=40 K. In a mean-field approach when considering the interchain interactions, we obtain the total interchain coupling to be about 16 K. The LRO anomaly at TN is also observed in the specific heat CP(T) data and is not sensitive to an applied magnetic field up to 90 kOe. A 51V NMR signal corresponding to the nonmagnetic vanadium was observed. Anomalies at 6 K were observed in the variation with temperature of the 51V NMR linewidth and the spin-lattice relaxation rate 1/T1 indicating that they are sensitive to the LRO onset and fluctuations at the magnetic V sites. The existence of two components (one short and another long) is observed in the spin-spin relaxation rate 1/T2 data in the vicinity of TN. The shorter component seems to be intimately connected with the magnetically ordered state. We suggest that both magnetically ordered and nonlong-range-ordered (non-LRO) regions coexist in this compound below the long-range-ordering temperature.

  12. 11H-Pyrido[3',2':4,5]pyrrolo[3,2-c]cinnoline and pyrido[3',2':4,5]pyrrolo[1,2-c][1,2,3]benzotriazine: two new ring systems with antitumor activity.

    PubMed

    Parrino, Barbara; Carbone, Anna; Muscarella, Marina; Spanò, Virginia; Montalbano, Alessandra; Barraja, Paola; Salvador, Alessia; Vedaldi, Daniela; Cirrincione, Girolamo; Diana, Patrizia

    2014-11-26

    Derivatives of new ring systems 11H-pyrido[3',2':4,5]pyrrolo[3,2-c]cinnoline and pyrido[3',2':4,5]pyrrolo[1,2-c][1,2,3]benzotriazine have been prepared from the key intermediates 2-(1H-pyrrolo[2,3-b]pyridin-2-yl)anilines in excellent yields (94-99%) and screened by the National Cancer Institute (Bethesda, MD) on about 60 human tumor cell lines derived from nine cancer cell types. The tested compounds exhibited antiproliferative activity against all the human cell lines, showing comparable MG_MID (mean graph midpoint) values in the range of 0.74-1.15 μM. A particular efficacy was observed against the leukemia subpanel (GI50 = 0.73-0.0090 μM). Flow cytometric analysis of the cell cycle demonstrated an increase in the percentage of cells in the G2/M phase. The compounds caused apoptosis of the cells, mitochondrial depolarization, generation of reactive oxygen species, and activation of caspase-3, caspase-8, and caspase-9. Moreover, they acted as topoisomerase I inhibitors.

  13. Design of the Core 2-4 GHz Betatron Equalizer

    SciTech Connect

    Deibele, C.; /Fermilab

    2000-01-01

    The core betatron equalizer in the Accumulator in the Antiproton Source at Fermilab needed to be upgraded. The performance could be rated as only circa 650 MHz when the system was a 2 GHz system. The old equalizer did not correct for the strong phase mismatch for the relatively strong gain of the system slightly below 2 GHz. The design corrects this phase mismatch and is relatively well matched both in and out of band.

  14. Cosmic Microwave Background Observations with a Compact Heterogeneous 150 GHz Interferometer in Chile

    NASA Astrophysics Data System (ADS)

    Fowler, J. W.; Doriese, W. B.; Marriage, T. A.; Tran, H. T.; Aboobaker, A. M.; Dumont, C.; Halpern, M.; Kermish, Z. D.; Loh, Y.-S.; Page, L. A.; Staggs, S. T.; Wesley, D. H.

    2005-01-01

    We report on the design, first observing season, and analysis of data from a new prototype millimeter-wave interferometer, MINT. MINT consists of four 145 GHz SIS mixers operating in double-sideband mode in a compact heterogeneous configuration. The signal band is subdivided by a monolithic channelizer, after which the correlations between antennas are performed digitally. The typical receiver sensitivity in a 2 GHz band is 1.4 mK s1/2. The primary beams are 0.45d and 0.30d FWHM, with fringe spacing as small as 0.1d. MINT observed the cosmic microwave background (CMB) from Cerro Toco, in the Chilean Altiplano. The site quality at 145 GHz is good, with median nighttime atmospheric temperature of 9 K at zenith (exclusive of the CMB). Repeated observations of Mars, Jupiter, and a telescope-mounted calibration source establish the phase and magnitude stability of the system. MINT is the first interferometer dedicated to CMB studies to operate above 50 GHz. The same type of system can be used to probe the Sunyaev-Zel'dovich effect in galaxy clusters near the SZ null at 217 GHz. We give the essential features of MINT and present an analysis of sideband-separated, digitally sampled data recorded by the array. Based on 215 hours of data taken in late 2001, we set an upper limit on the CMB anisotropy in a band of width Δl=700 around l=1540 of δT<105 μK (95% confidence). Increased sensitivity can be achieved with more integration time, greater bandwidth, and more elements.

  15. The Canadian approach to the development of communications by satellite in the 12-GHz band

    NASA Astrophysics Data System (ADS)

    Bowen, R. R.

    1981-08-01

    WARC-79 made significant changes to how the 12-GHz band will be used in Region 2. In particular, it decided that the 12-GHz band in Region 2 will extend upwards the 12.7 GHz, and that the upper portion of the overall band (11.7 to 12.7 GHz), will be planned at the 1983 Regional Conference. The paper describes these allocation changes and how satellite systems are being developed in Canada under these new regulations.

  16. Electron-beam buncher to operate over the frequency range 1-4 GHz

    SciTech Connect

    Goldberg, D.A.; Arthur, A.A.; Flood, W.S.; Voelker, F.

    1983-03-01

    We present a description of an electron buncher to be installed in the terminal of a Van de Graaff, which is to produce a modulated beam over the frequency range 1-4 GHz. The modulator geometry has been optimized so that the modulation amplitude should be nearly constant over the frequency ranges 1-2 GHz and 2-4 GHz. Preliminary results indicate the device works as predicted.

  17. Photostability and Performance of Polystyrene Films Containing 1,2,4-Triazole-3-thiol Ring System Schiff Bases.

    PubMed

    Ali, Gassan Q; El-Hiti, Gamal A; Tomi, Ivan Hameed R; Haddad, Raghad; Al-Qaisi, Alaa J; Yousif, Emad

    2016-12-09

    Series of 4-(4-substituted benzylideneamino)-5-(3,4,5-trimethoxyphenyl)-4H-1,2,4-triazole-3-thiols were synthesized and their structures were confirmed. The synthesized Schiff bases were used as photostabilizers for polystyrene against photodegradation. Polystyrene polymeric films containing synthesized Schiff bases (0.5% by weight) were irradiated (λmax = 365 nm and light intensity = 6.43 × 10(-9) ein·dm(-3)·s(-1)) at room temperature. The photostabilization effect of 1,2,4-triazole-3-thiols Schiff bases was determined using various methods. All the additives used enhanced the photostability of polystyrene films against irradiation compared with the result obtained in the absence of Schiff base. The Schiff bases can act as photostabilizers for polystyrene through the direct absorption of UV radiation and/or radical scavengers.

  18. Spin-(1)/(2) XXZ Chain System Cs2CoCl4 in a Transverse Magnetic Field

    NASA Astrophysics Data System (ADS)

    Breunig, O.; Garst, M.; Sela, E.; Buldmann, B.; Becker, P.; Bohatý, L.; Müller, R.; Lorenz, T.

    2013-11-01

    Comparing high-resolution specific heat and thermal expansion measurements to exact finite-size diagonalization, we demonstrate that Cs2CoCl4 for a magnetic field along the crystallographic b axis realizes the spin-(1)/(2) XXZ chain in a transverse field. Exploiting both thermal as well as virtual excitations of higher crystal-field states, we find that the spin chain is in the XY limit with an anisotropy Jz/J⊥≈0.12, substantially smaller than previously believed. A spin-flop Ising quantum phase transition occurs at a critical field of μ0Hbcr≈2T before around 3.5 T the description in terms of an effective spin-(1)/(2) chain becomes inapplicable.

  19. Spin-1/2 XXZ chain system Cs2CoCl4 in a transverse magnetic field.

    PubMed

    Breunig, O; Garst, M; Sela, E; Buldmann, B; Becker, P; Bohatý, L; Müller, R; Lorenz, T

    2013-11-01

    Comparing high-resolution specific heat and thermal expansion measurements to exact finite-size diagonalization, we demonstrate that Cs(2)CoCl(4) for a magnetic field along the crystallographic b axis realizes the spin-1/2 XXZ chain in a transverse field. Exploiting both thermal as well as virtual excitations of higher crystal-field states, we find that the spin chain is in the XY limit with an anisotropy J(z)/J[perpindicular] ≈ 0.12, substantially smaller than previously believed. A spin-flop Ising quantum phase transition occurs at a critical field of μ(0)H(b)(cr) ≈ 2 T before around 3.5 T the description in terms of an effective spin-1/2 chain becomes inapplicable.

  20. A systems-level model reveals that 1,2-Propanediol utilization microcompartments enhance pathway flux through intermediate sequestration

    PubMed Central

    Jakobson, Christopher M.; Slininger, Marilyn F.

    2017-01-01

    The spatial organization of metabolism is common to all domains of life. Enteric and other bacteria use subcellular organelles known as bacterial microcompartments to spatially organize the metabolism of pathogenicity-relevant carbon sources, such as 1,2-propanediol. The organelles are thought to sequester a private cofactor pool, minimize the effects of toxic intermediates, and enhance flux through the encapsulated metabolic pathways. We develop a mathematical model of the function of the 1,2-propanediol utilization microcompartment of Salmonella enterica and use it to analyze the function of the microcompartment organelles in detail. Our model makes accurate estimates of doubling times based on an optimized compartment shell permeability determined by maximizing metabolic flux in the model. The compartments function primarily to decouple cytosolic intermediate concentrations from the concentrations in the microcompartment, allowing significant enhancement in pathway flux by the generation of large concentration gradients across the microcompartment shell. We find that selective permeability of the microcompartment shell is not absolutely necessary, but is often beneficial in establishing this intermediate-trapping function. Our findings also implicate active transport of the 1,2-propanediol substrate under conditions of low external substrate concentration, and we present a mathematical bound, in terms of external 1,2-propanediol substrate concentration and diffusive rates, on when active transport of the substrate is advantageous. By allowing us to predict experimentally inaccessible aspects of microcompartment function, such as intra-microcompartment metabolite concentrations, our model presents avenues for future research and underscores the importance of carefully considering changes in external metabolite concentrations and other conditions during batch cultures. Our results also suggest that the encapsulation of heterologous pathways in bacterial

  1. A systems-level model reveals that 1,2-Propanediol utilization microcompartments enhance pathway flux through intermediate sequestration.

    PubMed

    Jakobson, Christopher M; Tullman-Ercek, Danielle; Slininger, Marilyn F; Mangan, Niall M

    2017-05-01

    The spatial organization of metabolism is common to all domains of life. Enteric and other bacteria use subcellular organelles known as bacterial microcompartments to spatially organize the metabolism of pathogenicity-relevant carbon sources, such as 1,2-propanediol. The organelles are thought to sequester a private cofactor pool, minimize the effects of toxic intermediates, and enhance flux through the encapsulated metabolic pathways. We develop a mathematical model of the function of the 1,2-propanediol utilization microcompartment of Salmonella enterica and use it to analyze the function of the microcompartment organelles in detail. Our model makes accurate estimates of doubling times based on an optimized compartment shell permeability determined by maximizing metabolic flux in the model. The compartments function primarily to decouple cytosolic intermediate concentrations from the concentrations in the microcompartment, allowing significant enhancement in pathway flux by the generation of large concentration gradients across the microcompartment shell. We find that selective permeability of the microcompartment shell is not absolutely necessary, but is often beneficial in establishing this intermediate-trapping function. Our findings also implicate active transport of the 1,2-propanediol substrate under conditions of low external substrate concentration, and we present a mathematical bound, in terms of external 1,2-propanediol substrate concentration and diffusive rates, on when active transport of the substrate is advantageous. By allowing us to predict experimentally inaccessible aspects of microcompartment function, such as intra-microcompartment metabolite concentrations, our model presents avenues for future research and underscores the importance of carefully considering changes in external metabolite concentrations and other conditions during batch cultures. Our results also suggest that the encapsulation of heterologous pathways in bacterial

  2. Unusual transformation of the diarylmethanol derivative into an unknown 1,2,3,6,7,10-hexahydroxylated anthracene system.

    PubMed

    Bałczewski, Piotr; Koprowski, Marek; Bodzioch, Agnieszka; Marciniak, Bernard; Rózycka-Sokołowska, Ewa

    2006-03-31

    10-Benzyloxy-1,2,3-trimethoxy-6,7-(methylene-1,3-dioxy)anthracene as a potential material for molecular electronics was synthesized from the O-benzyl-protected diarylmethanol derivative containing the 1,3-dioxyethylene acetal function via a one-pot procedure under acidic conditions (1 N HCl, methanol, 60 h) in 60% yield. The replacement of methanol for benzene resulted in hydrolysis of the acetal function in 96% yield.

  3. Description and evaluation of tropospheric chemistry and aerosols in the Community Earth System Model (CESM1.2)

    DOE PAGES

    Tilmes, S.; Lamarque, J. -F.; Emmons, L. K.; ...

    2015-01-01

    The Community Atmosphere Model (CAM), version 5, is now coupled to extensive tropospheric and stratospheric chemistry, called CAM5-chem, and is available in addition to CAM4-chem in the Community Earth System Model (CESM) version 1.2. The main focus of this paper is to compare the performance of configurations with internally derived "free running" (FR) meteorology and "specified dynamics" (SD) against observations from surface, aircraft, and satellite, as well as understand the origin of the identified differences. We focus on the representation of aerosols and chemistry. All model configurations reproduce tropospheric ozone for most regions based on in situ and satellite observations.more » However, shortcomings exist in the representation of ozone precursors and aerosols. Tropospheric ozone in all model configurations agrees for the most part with ozonesondes and satellite observations in the tropics and the Northern Hemisphere within the variability of the observations. Southern hemispheric tropospheric ozone is consistently underestimated by up to 25%. Differences in convection and stratosphere to troposphere exchange processes are mostly responsible for differences in ozone in the different model configurations. Carbon monoxide (CO) and other volatile organic compounds are largely underestimated in Northern Hemisphere mid-latitudes based on satellite and aircraft observations. Nitrogen oxides (NOx) are biased low in the free tropical troposphere, whereas peroxyacetyl nitrate (PAN) is overestimated in particular in high northern latitudes. The present-day methane lifetime estimates are compared among the different model configurations. These range between 7.8 years in the SD configuration of CAM5-chem and 8.8 years in the FR configuration of CAM4-chem and are therefore underestimated compared to observational estimations. We find that differences in tropospheric aerosol surface area between CAM4 and CAM5 play an important role in controlling the burden of

  4. Description and evaluation of tropospheric chemistry and aerosols in the Community Earth System Model (CESM1.2)

    SciTech Connect

    Tilmes, S.; Lamarque, J. -F.; Emmons, L. K.; Kinnison, D. E.; Ma, P. -L.; Liu, X.; Ghan, S.; Bardeen, C.; Arnold, S.; Deeter, M.; Vitt, F.; Ryerson, T.; Elkins, J. W.; Moore, F.; Spackman, J. R.; Val Martin, M.

    2015-01-01

    The Community Atmosphere Model (CAM), version 5, is now coupled to extensive tropospheric and stratospheric chemistry, called CAM5-chem, and is available in addition to CAM4-chem in the Community Earth System Model (CESM) version 1.2. The main focus of this paper is to compare the performance of configurations with internally derived "free running" (FR) meteorology and "specified dynamics" (SD) against observations from surface, aircraft, and satellite, as well as understand the origin of the identified differences. We focus on the representation of aerosols and chemistry. All model configurations reproduce tropospheric ozone for most regions based on in situ and satellite observations. However, shortcomings exist in the representation of ozone precursors and aerosols. Tropospheric ozone in all model configurations agrees for the most part with ozonesondes and satellite observations in the tropics and the Northern Hemisphere within the variability of the observations. Southern hemispheric tropospheric ozone is consistently underestimated by up to 25%. Differences in convection and stratosphere to troposphere exchange processes are mostly responsible for differences in ozone in the different model configurations. Carbon monoxide (CO) and other volatile organic compounds are largely underestimated in Northern Hemisphere mid-latitudes based on satellite and aircraft observations. Nitrogen oxides (NOx) are biased low in the free tropical troposphere, whereas peroxyacetyl nitrate (PAN) is overestimated in particular in high northern latitudes. The present-day methane lifetime estimates are compared among the different model configurations. These range between 7.8 years in the SD configuration of CAM5-chem and 8.8 years in the FR configuration of CAM4-chem and are therefore underestimated compared to observational estimations. We find that differences in tropospheric aerosol surface area between CAM4 and CAM5 play an important role in controlling the

  5. Design of the 0.5 - 1 GHz Planar Recycler Pickup and Kicker Antennas

    SciTech Connect

    Deibele, C.; /Fermilab

    1999-01-01

    The stochastic cooling system in the Recycler ring at Fermilab required the addition of a 0.5-1 GHz cooling system. This requirement dictated the design of a new antenna for this band of the system. The design problem is defined, method of design is illustrated, and the measurement data are reported. The Recycler is a storage ring comprised of mostly permanent magnets located in the tunnel of the Main Injector at Fermilab. The goal for the construction of the Recycler is to collect and store unused antiprotons from collisions in the Tevatron for use in future collisions in the Tevatron. It will both stochastically and electron cool these unused antiprotons before another collision experiment is possible in the Tevatron. By reusing the antiprotons the luminosity of the experiment can be increased faster. The Recycler will use three bands for its stochastic cooling system. It will reuse the existing designs from the Antiproton Source for the 1-2 GHz and 2-4 GHz systems, and it requires a new design for an additional lower frequency band for the 0.5-1 GHz system. Since the existing designs were fabricated using a microstrip topology it was desired that the new design use a similar topology so that the vacuum tank designs and supporting hardware be identical for all three bands. A primary difference between the design of the pickups/kickers of the Antiproton Source and the Recycler is a different aperture in the machine itself. The Recycler has a bigger aperture and consequently reusing the designs for the existing Antiproton Source pickups/kickers is not electrically optimal but is cost efficient. Measurements will be shown later in this paper for the design of the 0.5-1 GHz system showing the effect of the aperture on the antenna performance. A mockup of the Recycler tank was manufactured for designing and testing the 0.5-1 GHz pickups/kickers. The design procedure was an iterative process and required both a constant dialogue and also a strong relationship with a

  6. Olympus 20/30 GHz communications payload

    NASA Astrophysics Data System (ADS)

    Sartini, Lamberto; Sassorossi, Tiziano

    The 20/30 GHz communications payload, the first system of its type scheduled to operate in the Ka band, is designed to provide for communications systems test at 20/30 GHz over an area as large as Europe. To this end, two directive antennas with steerable beams, about one meter in diameter and connected to a transparent transponder, capable of supporting two narrow band channels (40 MHz) and one wideband channel (700 MHz), have been installed onboard the Olympus satellite. Experiments carried by the payload are described, including both point-to-point and multipoint teleconference services, a tele-education experiment, a transcommunications experiment with wideband signals, and a connection by digital transmission at 2048 Mbit/sec between small stations in Western Europe. Operating modes for the payload are outlined and the main results of the acceptance tests obtained on the first flight model are provided. A block diagram is included.

  7. Compact 0.3-to-1.125 GHz self-biased phase-locked loop for system-on-chip clock generation in 0.18 µm CMOS

    NASA Astrophysics Data System (ADS)

    Zhang, Zhao; Liu, Liyuan; Feng, Peng; Liu, Jian; Wu, Nanjian

    2016-04-01

    In this paper, we propose a compact ring-oscillator-based self-biased phase-locked loop (SBPLL) for system-on-chip (SoC) clock generation. It adopts the proposed triple-well NMOS source degeneration voltage-to-current (V-I) converter instead of the operational amplifier (OPAMP) based V-I converter and a proposed simple start-up circuit with a negligible area to save power and area. The SBPLL is implemented in the 0.18 µm CMOS process, and it occupies 0.048 mm2 active core. The measurement results show the SBPLL can generate output frequency in a wide range from 300 MHz to 1.125 GHz with a constant loop bandwidth that is around 5 MHz and a relatively low jitter performance that is less than 4.9 mUI over the entire covered frequency range. From -20 to 70 °C the rms jitter variation and loop bandwidth variation at 1.125 GHz are 0.2 ps and 350 kHz, respectively. The rms jitter performance variation of all covered frequency points is less than 10% in the supply range from 1.5 to 1.7 V. Such SBPLL shows robustness over environmental variation. The maximum power consumption is 5.6 mW with 1.6 V supply at an output frequency of 1.125 GHz.

  8. 16 channel GHz low noise SWIR photoreceivers

    NASA Astrophysics Data System (ADS)

    Bai, Xiaogang; Yuan, Ping; McDonald, Paul; Boisvert, Joseph; Chang, James; Woo, Robyn; Labios, Eduaro; Sudharsanan, Rengarajan; Krainak, Michael; Yang, Guangning; Sun, Xiaoli; Lu, Wei; McIntosh, Dion; Zhou, Qiugui; Campbell, Joe

    2012-06-01

    Future NASA light detection and ranging (LIDAR) mapping systems require multi-channel receivers with high sensitivity and bandwidth operating at 1-1.5 μm wavelengths. One of the ways to improve the system performance is to improve the sensitivity of photoreceiver. InGaAs avalanche photodiode (APD) sensor technology is considered for this wavelength region because of high reliability. However, commercially available InGaAs APDs have low sensitivity due to the high excess-noise of InP material. Spectrolab has been developing low excess noise InGaAs avalanche photodiodes (APDs) with impact ionization engineering (I2E) structures and recently, APDs with excess noise factor of 0.15 have been demonstrated using an I2E design. Single channel photoreceivers built using low noise I2E APDs show a noise equivalent power (NEP) of 150 fW/rt(Hz) over a bandwidth of 1 GHz, a record for InGaAs based APDs. A 16 channel GHz SWIR photoreceiver was designed and built at Spectrolab. The photoreceiver was designed to work with a custom fiber bundle which couples the light from telescope to detectors. The photoreceiver shows a system level NEP less than 300 fW/rt(Hz) with 1 GHz bandwidth.

  9. High efficiency IMPATT diodes for 60 GHz intersatellite link applications

    NASA Technical Reports Server (NTRS)

    Haugland, E. J.

    1984-01-01

    Intersatellite links are expected to play an increasingly important role in future satellite systems. Improved components are required to properly utilize the wide bandwidth allocated for intersatellite link applications around 60 GHz. IMPATT diodes offer the highest potential performance as solid state power sources for a 60 GHz transmitter. Presently available devices do not have the desired power and efficiency. High efficiency, high power IMPATT diodes for intersatellite link applications are being developed by NASA and other government agencies. This paper describes the development of high efficiency 60 GHz IMPATT diodes by NASA. These programs are cofunded by the U.S. Air Force, Space Division.

  10. High efficiency IMPATT diodes for 60 GHz intersatellite link applications

    NASA Technical Reports Server (NTRS)

    Haugland, E. J.

    1984-01-01

    Intersatellite links are expected to play an increasingly important role in future satellite systems. Improved components are required to properly utilize the wide bandwidth allocated for intersatellite link applications around 60 GHz. IMPATT diodes offer the highest potential performance as solid state power sources for a 60 GHz transmitter. Presently available devices do not have the desired power and efficiency. High efficiency, high power IMPATT diodes for intersatellite link applications are being developed by NASA and other government agencies. The development of high efficiency 60 GHz IMPATT diodes by NASA is described.

  11. ATS-6 attenuation diversity measurements at 20 and 30 GHz

    NASA Technical Reports Server (NTRS)

    Vogel, W. J.; Straiton, A. W.; Fannin, B. M.; Wagner, N. K.

    1975-01-01

    The results of data obtained at The University of Texas at Austin in conjunction with the ATS-6 millimeter wave experiment are presented. Attenuation measurements at 30 GHz and sky noise data at 20 GHz were obtained simultaneously at each of two sites separated by 11 km. Space diversity reduces outage time for a system in Austin, Texas with a 10 dB fade margin at 30 GHz from 15 hours to 16 minutes per year. The maximum cloud height shows a good correlation to the maximum attenuations measured.

  12. Microwave spectrum of 1,2-propanediol

    NASA Astrophysics Data System (ADS)

    Lovas, F. J.; Plusquellic, D. F.; Pate, Brooks H.; Neill, Justin L.; Muckle, Matthew T.; Remijan, Anthony J.

    2009-09-01

    The microwave spectrum of the sugar alcohol 1,2-propanediol (CH 3CHOHCH 2OH) has been measured over the frequency range 6.5-25.0 GHz with several pulsed-beam Fourier-transform microwave spectrometers. Seven conformers of 1,2-propanediol have been assigned and ab initio electronic structure calculations of the 10 lowest energy forms have been calculated. Stark effect measurements were carried out on several of the lowest energy conformers to provide accurate determinations of the dipole moment components and assist in conformer assignment.

  13. Signaling through ERK1/2 controls myelin thickness during myelin repair in the adult central nervous system.

    PubMed

    Fyffe-Maricich, Sharyl L; Schott, Alexandra; Karl, Molly; Krasno, Janet; Miller, Robert H

    2013-11-20

    Oligodendrocytes, the myelin-forming cells of the CNS, exquisitely tailor the thickness of individual myelin sheaths to the diameter of their target axons to maximize the speed of action potential propagation, thus ensuring proper neuronal connectivity and function. Following demyelinating injuries to the adult CNS, newly formed oligodendrocytes frequently generate new myelin sheaths. Following episodes of demyelination such as those that occur in patients with multiple sclerosis, however, the matching of myelin thickness to axon diameter fails leaving remyelinated axons with thin myelin sheaths potentially compromising function and leaving axons vulnerable to damage. How oligodendrocytes determine the appropriate thickness of myelin for an axon of defined size during repair is unknown and identifying the signals that regulate myelin thickness has obvious therapeutic implications. Here, we show that sustained activation of extracellular-regulated kinases 1 and 2 (ERK1/2) in oligodendrocyte lineage cells results in accelerated myelin repair after injury, and is sufficient for the generation of thick myelin sheaths around remyelinated axons in the adult mouse spinal cord. Our findings suggest a model where ERK1/2 MAP kinase signaling acts as a myelin thickness rheostat that instructs oligodendrocytes to generate axon-appropriate quantities of myelin.

  14. Development of 30/20 GHz satellite antenna structures

    NASA Astrophysics Data System (ADS)

    Minomo, M.; Yasaka, T.

    1986-08-01

    An antenna structural design for a large capacity communication satellite using 13 beams in the 30/20GHz frequency bands is discussed. This design is to be utilized in developing a more cost effective domestic satellite communication system for Japan. This system requires 2 high precision deployable antennas with projected aperture diameters of 3.5m at 20GHz and 2.5m at 30GHz. The in-orbit demonstration will use the ETS-6 satellite. Based on experience in the development of spaceborne antennas for 30/20GHz bands (e.g., for the CS-2 and CS-3 satellites) activities in structural design of high precision deployable antennas show the truss reflector structure is promising for achieving required structural properties.

  15. New fluorescent heterocyclic systems from imidazo[1,2-a]pyridine: Design, synthesis, spectral studies and quantum-chemical investigations

    NASA Astrophysics Data System (ADS)

    Pordel, Mehdi; Chegini, Hamed; Ramezani, Shirin; Daee, Mohammadreza

    2017-02-01

    Two new fluorescent heterocyclic systems dipyrido[1‧,2‧:1,2]imidazo[4,5-b:4,5-e]pyridine-13-carbonitrile and pyrido[1‧,2‧:1,2]imidazo[4,5-b]pyrido[2‧,1‧:2,3]imidazo[4,5-e]pyridine-13-carbonitrile were synthesized by one-pot reaction of imidazo[1,2-a]pyridine with 2-(imidazo[1,2-a]pyridin-3-yl)acetonitrile and 2-(imidazo[1,2-a]pyridin-2-yl)acetonitrile, respectively, in MeOH/KOH solution via the nucleophilic substitution of hydrogen in high yields. Spectral and analytical data have confirmed the structures of the synthesized dyes. The optical and solvatochromic properties of the compounds were investigated and the results showed that they exhibited interesting photophysical properties. Density functional theory (DFT) calculations of fluorescent dyes were performed to provide the optimized geometries and relevant frontier orbitals by using the B3LYP hybrid functional and the 6-311 ++ G(d,p) basis set. Calculated electronic absorption spectra were also obtained by time-dependent density functional theory (TD-DFT) method. In addition, electron density iso-surface map, intra- and intermolecular interactions of these fluorescent heterocyclic systems were evaluated by AIM (Atoms in Molecules) analysis.

  16. A novel class of extended pi-conjugated systems: one-pot synthesis of bis-3-aminoimidazo[1,2-a]pyridines, pyrimidines and pyrazines.

    PubMed

    Shaabani, Ahmad; Soleimani, Ebrahim; Maleki, Ali; Moghimi-Rad, Jafar

    2009-05-01

    Bis-3-aminoimidazo[1, 2-a] pyridines, pyrimidines and pyrazines as extended pi-conjugated systems were synthesized for the first time by a novel pseudo five-component condensation of 2-aminopyridine pyrimidines and pyrazines derivatives with terephthalaldehyde or isoph-thalaldehyde and isocyanides in the presence of p-toluene-sulfonic acid in methanol.

  17. Neutron scattering study in the spin-1/2 ladder system: Sr{sub 14}Cu{sub 24}O{sub 41}

    SciTech Connect

    Matsuda, M.; Katsumata, K.; Shapiro, S.M.; Shirane, G.

    1996-10-01

    Inelastic neutron scattering measurements were performed on the S=1/2 quasi-one-dimensional system Sr{sub 14}Cu{sub 24}O{sub 41}, which has both simple chains and two-leg ladders of copper ions. We have observed that both the chain and the ladder exhibit a spin gap, which originates from a dimerized state.

  18. The 8-18 GHz radar spectrometer

    NASA Technical Reports Server (NTRS)

    Bush, T. F.; Ulaby, F. T.

    1973-01-01

    The design, construction, testing, and accuracy of an 8-18 GHz radar spectrometer, an FM-CW system which employs a dual antenna system, is described. The antennas, transmitter, and a portion of the receiver are mounted at the top of a 26 meter hydraulic boom which is in turn mounted on a truck for system mobility. HH and VV polarized measurements are possible at incidence angles ranging from 0 deg. to 80 deg. Calibration is accomplished by referencing the measurements against a Luneberg lens of known radar cross section.

  19. 140 GHz microwave FEL experiments using ELF-II

    SciTech Connect

    Throop, A.L.; Jong, R.A.; Atkinson, D.P.; Clark, J.C.; Felker, B.; Ferguson, S.W.; Makowski, M.A.; Nexsen, W.E.; Stallard, B.W.; Stever, R.D.; Turner, W.C.

    1989-09-01

    We describe the modeling, the experimental facility, and the initial operating results for ELF-II, an induction-linac based free-electron laser designed to produce up to 2 GW of peak power at 140 GHz. ELF-II is the initial configuration of an FEL system which will eventually produce up to 2 MW of average power at a frequency of 250 GHz, for use in plasma heating experiments in the Microwave Tokamak Experiment. 6 refs., 9 figs.

  20. Pole STAR: An 810 GHz Array Receiver for AST/RO

    NASA Astrophysics Data System (ADS)

    Groppi, C.; Walker, C.; Hungerford, A.; Kulesa, C.; Jacobs, K.; Kooi, J.

    We are constructing a 4-channel receiver at 810 GHz for use on the Antarctic Submillimeter Telescope and Remote Observatory located at the South Pole (AST/RO). The 810 GHz mixers and junctions for the array are being provided by KOSMA. The mixers are housed in a hybrid cryostat located in a warm Coude' room just below the 1.7 m telescope. A pair of parabolic mirrors will be used to reimage the telescope's focal plane through a Martin-Puplett LO diplexer onto a 2x2 array of lenses. The lenses efficiently couple the telescope to each mixer's corrugated feedhorn. The SIS junction is matched to the waveguide by an on-chip tuner and a single, fixed backshort. The 1-2 GHz IF output of each mixer is fed into a low-noise, balanced, HEMT amplifier. All bias signals are provided by a computer controlled bias system, which is fully optically isolated from the control computer. This system provides automated adjustment and optimization of bias levels with web based monitoring. The IF outputs are further processed at room temperature and fed into a 4-channel array AOS constructed by KOSMA. A Gunn oscillator (J. Carlstrom) and multiplier (Erickson & Narayanan) are used to drive the array.

  1. Structural and magnetic phase transition in samarium hydrogen system SmH{sub x} (x=1, 2, 3)

    SciTech Connect

    Priyanga, G. Sudha; Rajeswarapalanichamy, R.; Santhosh, M.; Iyakutti, K.

    2015-06-24

    We report ab-initio calculations for the structural and magnetic phase transition of SmH{sub x} (x= 1, 2, 3) using the Vienna ab-initio simulation package (VASP). The non-spin polarized (NSP) and spin polarized (SP) calculations are performed for these hydrides at normal and high pressure. It is found that these compounds are stable in ferromagnetic state at normal pressure. The calculated lattice parameters and bulk modulus of these hydrides are in good agreement with the available experimental results. A pressure-induced structural phase transition from cubic to hexagonal phase in SmH and SmH{sub 2} and hexagonal to cubic phase in SmH{sub 3} is predicted. A pressure-induced ferromagnetic to nonmagnetic phase transition is observed in SmH, SmH{sub 2} and SmH{sub 3} at the pressures of 104 GPa, 76 GPa and 81 GPa respectively. Ferromagnetism is quenched in mono, di and tri hydrides at high pressures.

  2. Effects, in an in-vivo model system, of 1,2,3,4-tetrahydroisoquinoline on glioma.

    PubMed

    Kang, Gyong-Suk; Wang, Xiang Di; Mohler, Michael L; Kirichenko, Oleg V; Patil, Renukadevi; Orr, William E; Miller, Duane D; Geisert, Eldon E

    2008-10-01

    The effects of 1-(biphenyl-4-ylmethyl)-1,2,3,4-tetrahydroisoquinoline-6,7-diol (EDL-155) on the growth of glioma was tested in vitro and in vivo. Normal cultured rat astrocytes and C6 rat glioma were used as a differential screen to test the effects of EDL-155. The compound was preferentially cytotoxic for C6 glioma (EC50=1.5 micromol/l) relative to cultured neonatal astrocytes (EC50=27.4 micromol/l). When compared with a standard chemotherapeutic agent, carmustine (1,3-bis[2-chloroethyl]-1-nitrosourea), or temozolomide, EDL-155 was more selective and more potent in our differential tissue culture assay. The effect of EDL-155 was also tested in an animal model in which C6 glioma was transplanted into the brains of Sprague-Dawley rats. EDL-155 was delivered directly onto the tumor by an osmotic minipump directly into the brain or by intraperitoneal injection. Animals treated with EDL-155 had significantly smaller tumors than did control animals treated with carrier solution. We observed anatomical changes in cultured glioma cells treated with EDL-155 that were consistent with selective destruction of mitochondria and the induction of autophagy. These changes were not observed in normal astrocytes cultured from rat pups. The selective killing of glioma in tissue culture and in the rat brain models indicates that EDL-155 has potential therapeutic value in treating this type of brain cancer.

  3. cis-1,2-Dichloroethylene

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 09 / 006 F www.epa.gov / iris TOXICOLOGICAL REVIEW OF cis - 1,2 - DICHLOROETHYLENE and trans - 1,2 - DICHLOROETHYLENE ( CAS Nos . cis : 156 - 59 - 2 ; trans : 156 - 60 - 5 ; mixture : 540 - 59 - 0 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS )

  4. System Critical Design Audit (CDA). Books 1, 2 and 3; [Small Satellite Technology Initiative (SSTI Lewis Spacecraft Program)

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Small Satellite Technology Initiative (SSTI) Lewis Spacecraft Program is evaluated. Spacecraft integration, test, launch, and spacecraft bus are discussed. Payloads and technology demonstrations are presented. Mission data management system and ground segment are also addressed.

  5. Critical behavior of AC antiferromagnetic and ferromagnetic susceptibilities of a spin-1/2 > metamagnetic Ising system

    NASA Astrophysics Data System (ADS)

    Gulpinar, Gul; Vatansever, Erol

    2012-03-01

    In this study, the temperature variations of the equilibrium and the non-equilibrium antiferromagnetic and ferromagnetic susceptibilities of a metamagnetic system are examined near the critical point. The kinetic equations describing the time dependencies of the total and staggered magnetizations are derived by utilizing linear response theory. In order to obtain dynamic magnetic relaxation behavior of the system, the stationary solutions of the kinetic equations in existence of sinusoidal staggered and physical external magnetic fields are performed. In addition, the static and dynamical mean field critical exponents are calculated in order to formulate the critical behavior of antiferromagnetic and ferromagnetic magnetic response of a metamagnetic system. Finally, a comparison of the findings of this study with previous theoretical and experimental studies is represented and it is shown that a good agreement is found with our results.

  6. One GHz digitizer for space based laser altimeter

    NASA Technical Reports Server (NTRS)

    Staples, Edward J.

    1991-01-01

    This is the final report for the research and development of the one GHz digitizer for space based laser altimeter. A feasibility model was designed, built, and tested. Only partial testing of essential functions of the digitizer was completed. Hybrid technology was incorporated which allows analog storage (memory) of the digitally sampled data. The actual sampling rate is 62.5 MHz, but executed in 16 parallel channels, to provide an effective sampling rate of one GHz. The average power consumption of the one GHz digitizer is not more than 1.5 Watts. A one GHz oscillator is incorporated for timing purposes. This signal is also made available externally for system timing. A software package was also developed for internal use (controls, commands, etc.) and for data communication with the host computer. The digitizer is equipped with an onboard microprocessor for this purpose.

  7. Imaging, Doppler, and spectroscopic radars from 95 to 700 GHz

    NASA Astrophysics Data System (ADS)

    Cooper, Ken B.

    2016-05-01

    Imaging, Doppler, and spectroscopic radars from 95 to 700 GHz, all using the frequency-modulated continuous-wave technique, are in various stages of development for both defense and science applications at the Jet Propulsion Laboratory. For standoff security screening, a 340 GHz imaging radar now achieves an 8.3 Hz frame, and it has been tested using power-efficient MMIC-based active multiplier sources into its front end. That system evolved from a 680 GHz security radar platform, which has also been modified to operate in a Doppler mode for probing the dynamics of blowing sand and sensing small-amplitude target vibrations. Meanwhile, 95 and 183 GHz radars based on similar RF architectures are currently being developed to probe cometary jets in space and, using a differential absorption technique, humidity inside upper-tropospheric clouds.

  8. A 20-GHz IMPATT transmitter

    NASA Technical Reports Server (NTRS)

    Chan, J. L.; Sun, C.

    1983-01-01

    The engineering development of a solid state transmitter amplifier operating in the 20 GHz frequency band. The development effort involved a variety of disciplines including IMPATT device development, circulator design, simple and multiple diode circuits designs, and amplifier integration and test.

  9. Integration of 100 GHz and 50 GHz spectral bandwidth wavelength demultiplexer using 2D photonic crystal

    NASA Astrophysics Data System (ADS)

    Balaji, V. R.; Murugan, M.; Robinson, S.

    2017-06-01

    The paper deals with the photonic crystal based demultiplexer that has been designed to separate the 100 GHz and 50 GHz channels in a single device. The proposed demultiplexer is designed to drop four unique wavelengths. The demultiplexer is consisted of bus waveguide, rectangular resonant cavity (RRC) and four dropping waveguide; the transmission of 100 GHz and 50 GHz channels are dropped separately. The operating wavelength range of the device lies between 1551nm to 1552nm for 0.4 nm channel spacing and 1554nm to 1559 for 0.8 nm channel spacing. This new methodology is expected to be applied in the future for the dual systems and the footprint and cost of the networking will also be significantly reduced.

  10. Federal Emergency Management Information System (FEMIS). Bill of Materials (BOM), FEMIS: Phase I, Version 1.2

    SciTech Connect

    Coonelly, T.F.; Gerhardstein, L.H.; Hucks, J.A.

    1995-07-01

    This paper describes the Bill of Materials (BOM) for the Federal Emergency Management Information System (FEMIS) for release 1.1. FEMIS runs on two computer platforms: A UNIX platform, employed as a data server, and a personal computer (PC) using a Windows NT operating environment. FEMIS will support the use of commercial off-the-shelf software (COTS) software applications and tools. The hardware set includes a UNIX data server, a PC Communications server (at the source of MET data only), and a number of PC Client workstations, peripheral devices and network support equipment as described in this document. Servers and PCs require the operating system, utility software, communications and other internal cards also listed in the following sections. Several configuration are possible at a CSEPP Site. In this description, a Site is understood to be comprised of several installations, including the depot, surrounding Immediate Response Zone (IRZ) and Protective Action Zone (PAZ) counties, and the state EOC. In general, the main differences between possible configurations are the number of users at an installation, the location of the UNIX data server, and the WAN link between installations. Two typical installation configurations are With Data Server and Without Data Server. The number of PC workstations may vary at an installation.

  11. Magnetic specific heat studies of two Ising spin 1/2 chain systems M(N3)2(bpy)

    NASA Astrophysics Data System (ADS)

    Hamida, Youcef; Danilovic, Dusan; Yuen, Tan; Li, Kunhao; Li, Jing

    2012-04-01

    M(N3)2(bpy) [where M = Cu(II), Co(II), N3 = azide, and bpy = 4,4'-bipyridine] are two newly synthesized metal-organic framework (MOF) systems, in which the divalent M ions are connected though the azide ligands forming almost ideal magnetic 1 D chains. Specific heat measurements were performed on these compounds and the magnetic specific heats were deduced using appropriate methods for estimating the lattice specific heat. The magnetic specific heat data were analyzed and fit to the Ising model. The exchange interaction J/kB values of 13.1 K for Cu(N3)2(bpy) and 8.2 K for Co(N3)2(bpy) were obtained and compared to the J values from fitting the measured magnetic susceptibility data.

  12. An inductorless CMOS programmable-gain amplifier with a > 3 GHz bandwidth for 60 GHz wireless transceivers

    NASA Astrophysics Data System (ADS)

    Wei, Zhu; Baoyong, Chi; Lixue, Kuang; Wen, Jia; Zhihua, Wang

    2014-10-01

    An inductorless wideband programmable-gain amplifier (PGA) for 60 GHz wireless transceivers is presented. To attain wideband characteristics, a modified Cherry—Hooper amplifier with a negative capacitive neutralization technique is employed as the gain cell while a novel circuit technique for gain adjustment is adopted; this technique can be universally applicable in wideband PGA design and greatly simplifying the design of wideband PGA. By cascading two gain cells and an output buffer stage, the PGA achieves the highest gain of 30 dB with the bandwidth much wider than 3 GHz. The PGA has been integrated into one whole 60 GHz wireless transceiver and implemented in the TSMC 65 nm CMOS process. The measurements on the receiver front-end show that the receiver front-end achieves an 18 dB variable gain range with a > 3 GHz bandwidth, which proves the proposed PGA achieves an 18 dB variable gain range with a bandwidth much wider than 3 GHz. The PGA consumes 10.7 mW of power from a 1.2-V supply voltage with a core area of only 0.025 mm2.

  13. Phase Diagrams for the ν = 1/2 Fractional Quantum Hall Effect in Electron Systems Confined to Symmetric, Wide GaAs Quantum Wells

    NASA Astrophysics Data System (ADS)

    Pfeiffer, L. N.; Shabani, J.; Liu, Y.; Shayegan, M.; West, K. W.; Baldwin, K. W.

    2014-03-01

    We report an experimental investigation of fractional quantum Hall effect (FQHE) at the even-denominator Landau level filling factor ν = 1/2 in high quality wide GaAs quantum wells. The quasi-two-dimensional electron systems we study are confined to GaAs quantum wells with widths, W, ranging from 41 to 96 nm and have variable densities in the range of 4 ×1010 to 4 ×1011 cm-2 . We present several experimental phase diagrams for the stability of the ν = 1/2 FQHE in these quantum wells. We find that the densities at which the ν = 1/2 FQHE is stable are larger for narrower quantum wells. Moreover, even a slight charge distribution asymmetry destabilizes the ν = 1/2 FQHE and turns the electron system into a compressible state. We also present a plot of the subband separation (ΔSAS), which characterizes the interlayer tunneling, vs density for various W. Finally, we summarize the experimental data in a diagram that takes into account the relative strengths of the inter-layer and intra-layer Coulomb interactions and ΔSAS. We compare this experimental phase diagram of normalized inter-layer distance vs tunneling to recent theoretical calculations which have been used to conclude a two-component origin for the ν = 1/2 FQHE. A portion of this work was performed at the National High Magnetic Field Laboratory which is supported by NSF Cooperative Agreement No. DMR-1157490, the State of Florida and the US DOE.

  14. User's manual for the upper Delaware River riverine environmental flow decision support system (REFDSS), Version 1.1.2

    USGS Publications Warehouse

    Talbert, Colin; Maloney, Kelly O.; Holmquist-Johnson, Chris; Hanson, Leanne

    2014-01-01

    Between 2002 and 2006, the Fort Collins Science Center (FORT) at the U.S. Geological Survey (USGS) conducted field surveys, organized workshops, and performed analysis of habitat for trout and shad in the Upper Delaware River Basin. This work culminated in the development of decision support system software (the Delaware River DSS–DRDSS, Bovee and others, 2007) that works in conjunction with the Delaware River Basin Commission’s reservoir operations model, OASIS, to facilitate comparison of the habitat and water-delivery effects of alternative operating scenarios for the Basin. This original DRDSS application was developed in Microsoft Excel and is available to all interested parties through the FORT web site (http://www.fort.usgs.gov/Products/Software/DRDSS/). Initial user feedback on the original Excel-based DSS highlighted the need for a more user-friendly and powerful interface to effectively deliver the complex data and analyses encapsulated in the DSS. In order to meet this need, the USGS FORT and Northern Appalachian Research Branch (NARB) developed an entirely new graphical user interface (GUI) application. Support for this research was through the DOI WaterSmart program (http://www.doi.gov/watersmart/html/index.php) of which the USGS component is the National Water Census (http://water.usgs.gov/watercensus/WaterSMART.html). The content and methodology of the new GUI interface emulates those of the original DSS with a few exceptions listed below. Refer to Bovee and others (2007) for the original information. Significant alterations to the original DSS include: • We moved from Excel-based data storage and processing to a more powerful database back end powered by SQLite. The most notable effect of this is that the previous maximum temporal extent of 10 years has been replaced by a dynamic extent that can now cover the entire period of record for which we have data (1928–2000). • We incorporated interactive geographic information system (GIS

  15. Ab Initio Investigation of the Structure of the X2A', A2A″ (1 2Π) Spectral System of HCO: Investigation of the Magnetic Hyperfine Effects

    NASA Astrophysics Data System (ADS)

    Staikova, M.; Peric, M.; Engels, B.; Peyerimhoff, S. D.

    1994-08-01

    Results of an ab initio study of the hyperfine structure of the X2A', A2A″ (1 2Π) system of the formyl radical are presented. Special attention is paid to the analysis of the interplay between the vibronic and magnetic hyperfine effects. The results of computations are in very good agreement with the available experimental findings. The values for the hyperfine coupling constants in lower bending levels of both electronic species are predicted.

  16. Performance of Versions 1,2 and 3 of the Goddard Earth Observing System (GEOS) Chemistry-Climate Model (CCM)

    NASA Technical Reports Server (NTRS)

    Pawson, Steven; Stolarski, Richard S.; Nielsen, J. Eric; Duncan, Bryan N.

    2008-01-01

    Version 1 of the Goddard Earth Observing System Chemistry-Climate Model (GEOS CCM) was used in the first CCMVa1 model evaluation and forms the basis for several studies of links between ozone and the circulation. That version of the CCM was based on the GEOS-4 GCM. Versions 2 and 3 of the GEOS CCM are based on the GEOS-5 GCM, which retains the "Lin-Rood" dynamical core but has a totally different set of physical parameterizatiOns to GEOS-4. In Version 2 of the GEOS CCM the Goddard stratospheric chemistry module is retained. Difference between Versions 1 and 2 thus reflect the physics changes of the underlying GCMs. Several comparisons between these two models are made, several of which reveal improvements in Version 2 (including a more realistic representation of the interannual variability of the Antarctic vortex). In Version 3 of the GEOS CCM, the stratospheric chemistry mechanism is replaced by the "GMI COMBO" code that includes tropospheric chemistry and different computational approaches. An advantage of this model version. is the reduction of high ozone biases that prevail at low chlorine loadings in Versions 1 and 2. This poster will compare and contrast various aspects of the three model versions that are relevant for understanding interactions between ozone and climate.

  17. SOFish ver. 1.2 - A Decision Support System for Fishery Managers in Managing Complex Fish Stocks

    NASA Astrophysics Data System (ADS)

    Supriatna, A. K.; Sholahuddin, A.; Ramadhan, A. P.; Husniah, H.

    2016-01-01

    Sustainability is an important issue in a fishery industry. A manager of the fishery industry is responsible in deciding the best harvest that is able to sustain the industry while it should also guarantee the profitability of the industry. The most used concept in determining the best harvest in many fisheries industries is the Maximum Sustainable Yield (MSY). It represents the maximum amount of biomass that can be taken out from the fish population without harming the sustainability of the fishery. In other words, it is used to keep the population size stay over a threshold value of population level whenever harvesting activities is going on until indefinite time. In this paper we discuss a Decision Support System (DSS) for fishery managers in estimating the best harvest in a fishery industry. The best harvest is known as the Maximum Sustainable Yield (MSY) of the fishery. The DSS produces the MSY based on the discretization of some mathematical models of population growth, including the most popular models, such as Verhulst, Gompertz and Richards models. We also adding a biological complexity into the models, i.e. the presence of various degree of intra-specific competition of the population, which enhances the realism of the model and the DSS.

  18. Performance of Versions 1,2 and 3 of the Goddard Earth Observing System (GEOS) Chemistry-Climate Model (CCM)

    NASA Technical Reports Server (NTRS)

    Pawson, Steven; Stolarski, Richard S.; Nielsen, J. Eric; Duncan, Bryan N.

    2008-01-01

    Version 1 of the Goddard Earth Observing System Chemistry-Climate Model (GEOS CCM) was used in the first CCMVa1 model evaluation and forms the basis for several studies of links between ozone and the circulation. That version of the CCM was based on the GEOS-4 GCM. Versions 2 and 3 of the GEOS CCM are based on the GEOS-5 GCM, which retains the "Lin-Rood" dynamical core but has a totally different set of physical parameterizatiOns to GEOS-4. In Version 2 of the GEOS CCM the Goddard stratospheric chemistry module is retained. Difference between Versions 1 and 2 thus reflect the physics changes of the underlying GCMs. Several comparisons between these two models are made, several of which reveal improvements in Version 2 (including a more realistic representation of the interannual variability of the Antarctic vortex). In Version 3 of the GEOS CCM, the stratospheric chemistry mechanism is replaced by the "GMI COMBO" code that includes tropospheric chemistry and different computational approaches. An advantage of this model version. is the reduction of high ozone biases that prevail at low chlorine loadings in Versions 1 and 2. This poster will compare and contrast various aspects of the three model versions that are relevant for understanding interactions between ozone and climate.

  19. Terephthalate 1,2-dioxygenase system from Comamonas testosteroni T-2: purification and some properties of the oxygenase component.

    PubMed Central

    Schläfli, H R; Weiss, M A; Leisinger, T; Cook, A M

    1994-01-01

    Comamonas testosteroni T-2, grown in terephthalate (TER)-salts medium, synthesizes inducible enzymes that convert TER to (1R,2S)-dihydroxy-3,5-cyclohexadiene-1,4-dicarboxylic acid (DCD) and protocatechuate (PC). Anion-exchange chromatography of cell extracts yielded two sets of fractions, R and Z, that were necessary for oxygenation of TER to DCD; we termed this activity the TER dioxygenase system (TERDOS). An NAD(+)-dependent DCD dehydrogenase, which converted DCD to PC, overlapped all fractions R. No significant purification from fraction R, which contained an NADH-dependent reductase function(s) of TERDOS, was attained. Fraction Z, at the end of the gradient, contained essentially one protein, which was further purified by hydrophobic interaction chromatography. This component, Z, had the UV-visible spectrum and electron paramagnetic resonance characteristics of a Rieske [2Fe-2S] protein and was considered to be the oxygenase. M(r)s of about 126,000 for oxygenase Z under native conditions were observed. Oxygenase Z consisted of two subunits, alpha and beta, with M(r)s of 49,000 and 18,000, respectively, under denaturing conditions. We presume that this oxygenase has an alpha 2 beta 2 structure. The sequences of the N-terminal amino acids of each subunit were determined. The activity of the purified enzyme was enhanced about fivefold by addition of Fe2+. In the presence of O2, NADH, and fraction R, component Z catalyzed the stoichiometric transformation of TER to PC, with the intermediate formation of DCD. The reaction was confirmed as a dioxygenation when we observed incorporation of two oxygen atoms from 18O2 into PC. The substrate range of TERDOS appeared to be narrow; apart from TER, only 2,5-dicarboxypyridine and 1,4-dicarboxynaphthalene (of 11 compounds tested) were converted to a product. Images PMID:7961417

  20. Electric-field-temperature phase diagram of the ferroelectric relaxor system (1 - x)Bi1/2Na1/2TiO3 - xBaTiO3 doped with manganese

    NASA Astrophysics Data System (ADS)

    Sapper, Eva; Novak, Nikola; Jo, Wook; Granzow, Torsten; Rödel, Jürgen

    2014-05-01

    The electric-field-temperature phase diagram for the lead-free relaxor material (1 - x)(Bi1/2Na1/2)TiO3 - xBaTiO3 (x = 0.03, 0.06, and 0.09) doped with 0.5 mol% Mn (BNT-100xBT:Mn) was established. Transition lines between ergodic or nonergodic relaxor states and the field-induced ferroelectric state were determined at constant temperatures with electric-field-dependent measurements of the polarization as well as of the piezoelectric coefficient and permittivity. Near the depolarization temperature Td, the switching between two ferroelectric poling directions occurs in two steps via an intermediate relaxor state. This effect is closely related to the pinching of the ferroelectric hysteresis loop.

  1. Astrometry at 24 and 43 GHz

    NASA Technical Reports Server (NTRS)

    Lanyi, Gabor E.; Boboltz, D.; Charlot, P.; Fey, A.; Fomalont, E.; Gordon, D.; Jacobs, C. S.; Ma, C. - C.; Naudet, C. J.; Sovers, O. J.; Zhang, L. D.

    2003-01-01

    We describe the goals and initial results of a collaboration formed to survey extragalactic objects at radio frequencies of 24 and 43 GHz This survey is for extending the International Celestial Reference Frame (ICRF) that is the current coordinate system for astrometry and wh ich is the angular inertial frame of deep space navigation. In princ iple, the extension should lead to a more stable reference frame. We report upon our initial three 24-hour observing sessions involving about 100 radio sources at the VLBA.

  2. New JVLA observations at 3 GHz and 5.5 GHz of the "Kite" radio source in Abell 2626

    NASA Astrophysics Data System (ADS)

    Ignesti, A.; Gitti, M.; Brunetti, G.; Feretti, L.; Giovannini, G.

    2017-07-01

    Context. We report on new Karl Jansky Very Large Array (JVLA) observations performed at 3 GHz and 5.5 GHz of Abell 2626. The cluster has been the object of several studies in recent years due to its peculiar radio emission, which shows a complex system of symmetric radio arcs characterized by a steep spectrum. The origin of these radio sources is still unclear. Due to their mirror symmetry toward the center, it has been proposed that they may be created by pairs of precessing jets powered by the inner active galactic nuclei (AGN). Aims: The new JVLA observations were requested with the specific aim of detecting extended emission on frequencies higher than 1.4 GHz, in order to constrain the jet-precession model by analyzing the spectral index and radiative age patterns along the arcs. Methods: We performed a standard data reduction of the JVLA datasets with the software CASA. By combining the new 3 GHz data with the archival 1.4 GHz VLA dataset we produced a spectral index map of the extended emission, and then estimated the radiative age of the arcs by assuming that the plasma was accelerated in moving hot-spots tracing the arcs. Results: Thanks to the high sensitivity of the JVLA, we achieve the detection of the arcs at 3 GHz and extended emission at 5.5 GHz. We measure a mean spectral index <- 2.5 for the arcs up to 3 GHz. No clear trend in spectral index or radiative age is detected across the arcs, which may challenge the interpretation based on precession or put strong constraints on the jet-precession period. In particular, by analyzing the radiative age distribution along the arcs, we were able to provide for the first time a timescale <26 Myr of the jet-precession period.

  3. 32-GHz Wideband Maser Amplifier

    NASA Technical Reports Server (NTRS)

    Shell, J. S.; Neff, D. E.

    1990-01-01

    High-gain, wideband, microwave amplifier based on ruby cooled by liquid helium. Features include low input equivalent noise temperature and 400-MHz bandwidth. Design basically extension of previous reflected-wave masers built for frequency range of 18 to 26 GHz. Maser amplifier includes eight stages connected in reflected-wave configuration. Particularly useful for detection of weak microwave signals in radio astronomy and communications.

  4. 338-GHz Semiconductor Amplifier Module

    NASA Technical Reports Server (NTRS)

    Samoska, Lorene A.; Gaier, Todd C.; Soria, Mary M.; Fung, King Man; Rasisic, Vesna; Deal, William; Leong, Kevin; Mei, Xiao Bing; Yoshida, Wayne; Liu, Po-Hsin; Uyeda, Jansen; Lai, Richard

    2010-01-01

    Research findings were reported from an investigation of new gallium nitride (GaN) monolithic millimeter-wave integrated circuit (MMIC) power amplifiers (PAs) targeting the highest output power and the highest efficiency for class-A operation in W-band (75-110 GHz). W-band PAs are a major component of many frequency multiplied submillimeter-wave LO signal sources. For spectrometer arrays, substantial W-band power is required due to the passive lossy frequency multipliers.

  5. 32-GHz Wideband Maser Amplifier

    NASA Technical Reports Server (NTRS)

    Shell, J. S.; Neff, D. E.

    1990-01-01

    High-gain, wideband, microwave amplifier based on ruby cooled by liquid helium. Features include low input equivalent noise temperature and 400-MHz bandwidth. Design basically extension of previous reflected-wave masers built for frequency range of 18 to 26 GHz. Maser amplifier includes eight stages connected in reflected-wave configuration. Particularly useful for detection of weak microwave signals in radio astronomy and communications.

  6. Sixty GHz IMPATT diode development

    NASA Technical Reports Server (NTRS)

    Ma, Y. E.; Chen, J.; Benko, E.; Barger, M. J.; Nghiem, H.; Trinh, T. Q.; Kung, J.

    1985-01-01

    The objective of this program is to develop 60 GHz GaAs IMPATT Diodes suitable for communications applications. The performance goal of the 60 GHz IMPATT is 1W CW output power with a conversion efficiency of 15 percent and 10 year life time. During the course of the program, double drift (DD) GaAs IMPATT Diodes have been developed resulting in the state of the art performance at V band frequencies. A CW output power of 1.12 W was demonstrated at 51.9 GHz with 9.7 percent efficiency. The best conversion efficiency achieved was 15.3 percent. V band DD GaAs IMPATTs were developed using both small signal and large signal analyses. GaAs wafers of DD flat, DD hybrid, and DD Read profiles using molecular beam epitaxy (MBE) were developed with excellent doping profile control. Wafer evaluation was routinely made by the capacitance versus voltage (C-V) measurement. Ion mass spectrometry (SIMS) analysis was also used for more detailed profile evaluation.

  7. Highly Asymmetric Phase Diagram of a Poly(1,2-octylene oxide)-Poly(ethylene oxide) Diblock Copolymer System Comprising a Brush-Like Poly(1,2-octylene oxide) Block.

    PubMed

    Hamley, Ian W; O'Driscoll, Ben M D; Lotze, Gudrun; Moulton, Claire; Allgaier, Jürgen; Frielinghaus, Henrich

    2009-12-16

    The phase diagram of a series of poly(1,2-octylene oxide)-poly(ethylene oxide) (POO-PEO) diblock copolymers is determined by small-angle X-ray scattering. The Flory-Huggins interaction parameter was measured by small-angle neutron scattering. The phase diagram is highly asymmetric due to large conformational asymmetry that results from the hexyl side chains in the POO block. Non-lamellar phases (hexagonal and gyroid) are observed near f(PEO)  = 0.5, and the lamellar phase is observed for f(PEO)  ≥ 0.5.

  8. Zeno effect in degree of polarization of a single photon or quantum-state purity of a spin-1/2 system

    NASA Astrophysics Data System (ADS)

    Luis, Alfredo; Gonzalo, Isabel; Porras, Miguel A.

    2013-06-01

    We describe a version of the Zeno effect where the monitored physical property cannot be represented by a standard operator in the system space and the evolution to be prevented by observation is not unitary. This is the case of quantum-state purity of a spin-1/2 system, which is equivalent to the degree of polarization of a single photon. By a suitable embedding of the system (say, a single photon) in an enlarged space of a pair of photons, pure and fully mixed components lead to orthogonal subspaces, with lack of purity becoming equivalent to entanglement. By imposing desirable properties the representation of the system in the enlarged space is unique. We show that the Zeno effect is possible, and experimentally feasible, in the enlarged space. The peculiarity that photons in identical polarization states are involved in pairs to observe the dynamics of each photon allows us to refer it as the self-Zeno effect or Narcissus effect.

  9. 47 CFR 25.143 - Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz mobile-satellite...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Space Stations § 25.143 Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz... satellites, the blanket license will cover a specified number of space stations to operate in a specified... Requirements—(1) General Requirements. Each application for a space station system authorization in the 1.6/2.4...

  10. 47 CFR 25.143 - Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz mobile-satellite...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Space Stations § 25.143 Licensing provisions for the 1.6/2.4 GHz mobile-satellite service and 2 GHz... satellites, the blanket license will cover a specified number of space stations to operate in a specified... Requirements—(1) General Requirements. Each application for a space station system authorization in the 1.6/2.4...

  11. Ferrielectric phase in the (Bi1/2Na1/2)TiO3-Ba(Mg1/3Nb2/3)O3 system

    NASA Astrophysics Data System (ADS)

    Kitanaka, Yuuki; Makisumi, Kohei; Oshima, Yumiko; Noguchi, Yuji; Miyayama, Masaru; Torii, Shuki; Kamiyama, Takashi

    2015-10-01

    We have investigated the crystal structure of (1 - x)(Bi1/2Na1/2)TiO3-xBa(Mg1/3Nb2/3)O3 (BNT-BMN) by high-resolution neutron powder diffraction (NPD) analysis. Our NPD study combined with polarization hysteresis measurements for ceramics reveals that a boundary between rhombohedral R3c and tetragonal P4bm phases exists at x = 4-5%. The Rietveld analysis of the NPD data shows that the crystal structure with x = 10% has a single-phase tetragonal structure in space group P4bm, as has been reported for BNT-7%BaTiO3. The P4bm structure exhibits antiparallel displacements of A- and B-site cations, which results in a small spontaneous polarization (Ps) of 13.3 µC/cm2 (estimated from the refined structural parameters). The results obtained for BNT-10%BMN ceramics strongly suggest ferrielectric features; the application of electric fields induces a transition from the P4bm phase with a small Ps to other ferroelectric phases with a large Ps.

  12. Effect of pesticide 1-[6-chloro-3-methyl-pyridyl-8-nitro-7-methyl-1 2 3 5 6 7-hexahydro imidazo (1,2a)]-pyridine when responding to a wheat plant's antioxidant defense system.

    PubMed

    Wang, P; Yang, X; Huang, W W; Zhang, M; Lu, W H; Zhao, H T; Wang, J; Liu, H L; Dong, A J; Zhang, H; Xu, R B; Zou, P; Cheng, C L; Zhang, Y C; Jing, J

    2014-03-01

    The purpose of this research was to establish an analytical method for analysing the 1-[6-chloro-3-methyl-pyridyl-8-nitro-7-methyl-1 2 3 5 6 7-hexahydro imidazo-(1,2a)]-pyridine (IPP) residue levels and to evaluate the difference in plant growth and its physical condition. A high performance liquid chromatography connected to a diode array detector (HPLC-DAD) was also employed. The results showed that the content of protein and water soluble carbohydrate (WSC) treated by IPP were initially higher with a significant delayed decrease. The biomarker response showed, even at a lower dose rate, exposure to the IPP caused stress effects and modified the activity of superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT) and polyphenol oxidase (PPO). Different patterns of biomarker responses were observed by an increase in SOD and malondialdehyde (MDA), and differential effects for antioxidant enzymes with a decrease in CAT, POD and PPO. The conclusions show that this profile of biomarker variation could represent a useful method to characterise exposure to IPP in a wheat plant. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Studies of extraction and transport system for highly charged ion beam of 18 GHz superconducting electron cyclotron resonance ion source at Research Center for Nuclear Physics

    NASA Astrophysics Data System (ADS)

    Yorita, T.; Hatanaka, K.; Fukuda, M.; Ueda, H.; Yasuda, Y.; Morinobu, S.; Tamii, A.; Kamakura, K.

    2014-02-01

    An 18 GHz superconducting electron cyclotron resonance ion source is installed to increase beam currents and to extend the variety of ions especially for highly charged heavy ions which can be accelerated by cyclotrons of Research Center for Nuclear Physics (RCNP), Osaka University. The beam production developments of several ions from B to Xe have been already done [T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 79, 02A311 (2008) and T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 81, 02A332 (2010)] and the further studies for those beam extraction and its transport have been done in order to increase the beam current more. The plasma electrode, extraction electrode, and einzel lens are modified. Especially extraction electrode can be applied minus voltage for the beam extraction and it works well to improve the extracted beam current. The extraction voltage dependences of transmission and emittance also have been studied for beam current improvement which is injected into azimuthally varying field cyclotron at RCNP.

  14. Studies of extraction and transport system for highly charged ion beam of 18 GHz superconducting electron cyclotron resonance ion source at Research Center for Nuclear Physics

    SciTech Connect

    Yorita, T. Hatanaka, K.; Fukuda, M.; Ueda, H.; Yasuda, Y.; Morinobu, S.; Tamii, A.; Kamakura, K.

    2014-02-15

    An 18 GHz superconducting electron cyclotron resonance ion source is installed to increase beam currents and to extend the variety of ions especially for highly charged heavy ions which can be accelerated by cyclotrons of Research Center for Nuclear Physics (RCNP), Osaka University. The beam production developments of several ions from B to Xe have been already done [T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 79, 02A311 (2008) and T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 81, 02A332 (2010)] and the further studies for those beam extraction and its transport have been done in order to increase the beam current more. The plasma electrode, extraction electrode, and einzel lens are modified. Especially extraction electrode can be applied minus voltage for the beam extraction and it works well to improve the extracted beam current. The extraction voltage dependences of transmission and emittance also have been studied for beam current improvement which is injected into azimuthally varying field cyclotron at RCNP.

  15. Studies of extraction and transport system for highly charged ion beam of 18 GHz superconducting electron cyclotron resonance ion source at Research Center for Nuclear Physics.

    PubMed

    Yorita, T; Hatanaka, K; Fukuda, M; Ueda, H; Yasuda, Y; Morinobu, S; Tamii, A; Kamakura, K

    2014-02-01

    An 18 GHz superconducting electron cyclotron resonance ion source is installed to increase beam currents and to extend the variety of ions especially for highly charged heavy ions which can be accelerated by cyclotrons of Research Center for Nuclear Physics (RCNP), Osaka University. The beam production developments of several ions from B to Xe have been already done [T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 79, 02A311 (2008) and T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 81, 02A332 (2010)] and the further studies for those beam extraction and its transport have been done in order to increase the beam current more. The plasma electrode, extraction electrode, and einzel lens are modified. Especially extraction electrode can be applied minus voltage for the beam extraction and it works well to improve the extracted beam current. The extraction voltage dependences of transmission and emittance also have been studied for beam current improvement which is injected into azimuthally varying field cyclotron at RCNP.

  16. 47 CFR 25.136 - Licensing provisions for user transceivers in the 1.6/2.4 GHz, 1.5/1.6 GHz, and 2 GHz Mobile...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the 1.6/2.4 GHz, 1.5/1.6 GHz, and 2 GHz Mobile Satellite Services. 25.136 Section 25.136..., 1.5/1.6 GHz, and 2 GHz Mobile Satellite Services. In addition to the technical requirements specified in § 25.213, earth stations operating in the 1.6/2.4 GHz and 1.5/1.6 GHz Mobile Satellite...

  17. 47 CFR 25.136 - Licensing provisions for user transceivers in the 1.6/2.4 GHz, 1.5/1.6 GHz, and 2 GHz Mobile...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... the 1.6/2.4 GHz, 1.5/1.6 GHz, and 2 GHz Mobile Satellite Services. 25.136 Section 25.136..., 1.5/1.6 GHz, and 2 GHz Mobile Satellite Services. In addition to the technical requirements specified in § 25.213, earth stations operating in the 1.6/2.4 GHz and 1.5/1.6 GHz Mobile Satellite Services...

  18. 47 CFR 25.136 - Licensing provisions for user transceivers in the 1.6/2.4 GHz, 1.5/1.6 GHz, and 2 GHz Mobile...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... the 1.6/2.4 GHz, 1.5/1.6 GHz, and 2 GHz Mobile-Satellite Services. 25.136 Section 25.136..., 1.5/1.6 GHz, and 2 GHz Mobile-Satellite Services. In addition to the technical requirements specified in § 25.213, earth stations operating in the 1.6/2.4 GHz and 1.5/1.6 GHz Mobile-Satellite Services...

  19. Dynamics of the two-dimensional S=1/2 dimer system (C5H6N2F)2CuCl4

    SciTech Connect

    Hong, Tao; Gvasaliya, S. N.; Herringer, S.; Turnbull, M. M.; Landee, C.; Regnault, L.-P.; Boehm, Martin; Zheludev, A

    2011-01-01

    Inelastic neutron scattering was used to study a quantum S=1/2 antiferromagnetic Heisenberg system Bis(2-amino-5-fluoropyridinium) Tetrachlorocuprate(II). The magnetic excitation spectrum was shown to be dominated by long-lived excitations with an energy gap 1.07(3) meV. The measured dispersion relation is consistent with a simple two-dimensional square lattice of weakly-coupled spin dimers. Comparing the data to a random phase approximation treatment of this model gives the intra-dimer and inter-dimer exchange constants J=1.45(2) meV and J =0.31(3) meV, respectively.

  20. Microwave interferometer using 94-GHz solid-state sources

    SciTech Connect

    Coffield, F.E.; Thomas, S.R.; Lang, D.D.; Stever, R.D.

    1983-11-14

    A 94-GHz microwave interferometer has been designed for the Tandem Mirror Experiment Upgrade and the Mirror Fusion Test Facility to replace the 140-GHz system. The new system is smaller and has modular single-channel units designed for high reliability. It is magnetically shielded and can be mounted close to the machine, which allows the use of lower power solid-state sources. Test results of the 94-GHz prototype indicate that the phase resolution is better than 1/sup 0/, the Impatt FM noise is 5 MHz wide, and the Gunn FM noise is 6 kHz wide. This paper presents the antenna designs along with the test results and discusses the unique problems associated with diagnosing a high electron temperature plasma in the presence of electron cyclotron resonant heating.

  1. 47 CFR 25.143 - Licensing provisions for the 1.6/2.4 GHz Mobile-Satellite Service and 2 GHz Mobile-Satellite...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... a proposed system in the 1.6/2.4 GHz MSS frequency bands employs a non-geostationary constellation or constellations of satellites; (ii) That a system proposed to operate using non-geostationary...

  2. Optimization of the preconcentration system of cadmium with 1(2-thiazolylazo)-p-cresol using a knotted reactor and flame atomic absorption spectrometric detection.

    PubMed

    Cerutti, S; Ferreira, S L C; Gásquez, J A; Olsina, R A; Martinez, L D

    2004-08-30

    The present paper proposes an on-line preconcentration procedure for cadmium determination in drinking water samples. It is based on the precipitation of cadmium(II) ions on a knotted reactor (KR) using 1(2-thiazolylazo)-p-cresol (TAC) as complexing reagent. The optimization step was performed using a full factorial design involving the variables: pH, eluent concentration (nitric acid) and TAC concentration. The results of this experiment demonstrated that these variables at chosen levels are not statistically significant. Under optimized experimental established conditions, analytical parameters for the preconcentration method were: a detection limit of 40.0 ng/l, precision as relative standard deviation (RSD) of 1.2 and 1.0%, for cadmium concentration of 2.5 and 20.0 microg/l, respectively. The preconcentration factor considering the slopes of the analytical curves with and without preconcentration is 23 for a sample volume of 10 ml. This system shows a sampling frequency of 25 h(-1). In order to check the accuracy, the standard reference material, NIST SRM 1643d trace elements in water was analyzed. A comparison, using t-test demonstrates that there is not significant difference among the achieved results with proposed method and the certified values. The addition/recovery experiments in the samples analyzed demonstrated the accuracy and applicability of the system developed for cadmium determination in water samples.

  3. Transmission of Duobinary Signal in Optical 40 GHz Millimeter-Wave Radio-Over-Fiber Systems Utilizing Dual-Arm LiNbO3 Mach-Zehnder Modulator for Downstream

    NASA Astrophysics Data System (ADS)

    Dong-Nhat, Nguyen; Malekmohammadi, Amin

    2016-06-01

    In this paper, for the first time transmission of 2.5 Gb/s duobinary signal is investigated for the downlink direction in 40 GHz optical millimeter-wave generation or up-conversion, utilizing a dual-arm LiNb{O}_3 Mach-Zehnder modulator based on different modulation schemes, namely double- and single-sideband (DSB and SSB) and optical carrier suppression (OCS). The up-converted optical millimeter-wave employing OCS modulation scheme indicates the highest back-to-back received optical power and the smallest power penalty after long propagation in the single-mode fiber, in comparison to DSB and SSB. Directly modulated laser in association with OCS modulation scheme has been used to generate duobinary optical millimeter-wave signal in order to minimize the cost and complexity of the system.

  4. A 492 GHz cooled Schottky receiver for radio-astronomy

    NASA Technical Reports Server (NTRS)

    Hernichel, J.; Schieder, R.; Stutzki, J.; Vowinkel, B.; Winnewisser, G.; Zimmermann, Peter

    1992-01-01

    We developed a 492 GHz cooled GaAs Schottky receiver driven by a solid state local oscillator with a DSB noise temperature of 550 K measured at the telescope. The receiver-bandwidth is approx. equal to 1.0 GHz. Quasi-optical mirrors focus the sky and local oscillator radiation into the mixer. Stability analysis via the Allan variance method shows that the total system including a 1 GHz bandwidth acousto-optical spectrometer built in Cologne allows integration times up to 100 sec per half switching cycle. We successfully used the receiver at the KOSMA 3 m telescope on Gornergrat (3150m) located in the central Swiss Alps near Zermatt during January-February 1992 for observations of the 492 GHz, (CI) (3)P1 to (3)P0 fine structure line in several galactic sources. These observations confirm that Gornergrat is an excellent winter submillimeter site in accordance with previous predictions based on the atmospheric opacity from KOSMA 345 GHz measurements.

  5. Chronic exposure to a 1.439 GHz electromagnetic field used for cellular phones does not promote N-ethylnitrosourea induced central nervous system tumors in F344 rats.

    PubMed

    Shirai, Tomoyuki; Kawabe, Mayumi; Ichihara, Toshio; Fujiwara, Osamu; Taki, Masao; Watanabe, So-ichi; Wake, Kanako; Yamanaka, Yukio; Imaida, Katsumi; Asamoto, Makoto; Tamano, Seiko

    2005-01-01

    The present study was designed to evaluate whether a 2 year exposure to an electromagnetic field (EMF) equivalent to that generated by cellular phones can accelerate tumor development in the central nervous system (CNS) of rats. Brain tumorigenesis was initiated by an intrauterine exposure to N-ethylnitrosourea (ENU) on gestational day 18. A total of 500 pups were divided into five groups, each composed of 50 males and 50 females: Group 1, untreated control; Group 2, ENU alone; Groups 3-5, ENU + EMF (sham exposure and 2 exposure levels). A 1.439 GHz time division multiple access (TDMA) signal for the Personal Digital Cellular (PDC), Japanese standard cellular system was used for the exposure of the rat head starting from 5 weeks of age, 90 min a day, 5 days a week, for 104 weeks. Brain average specific absorption rate (SAR) was 0.67 and 2.0 W/kg for low and high exposures, respectively: whole body average SAR was less than 0.4 W/kg. There were no inter-group differences in body weights, food consumption, and survival rates. No increase in the incidences or numbers per group of brain and/or spinal cord tumors, either in the males or females, was detected in the EMF exposed groups. In addition, no clear changes in tumor types were evident. Thus, under the present experimental conditions, 1.439 GHz EMF exposure to the heads of rats for a 2 year period was not demonstrated to accelerate or affect ENU initiated brain tumorigenesis. 2004 Wiley-Liss, Inc.

  6. High sensitivity broadband 360GHz passive receiver for TeraSCREEN

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Oldfield, Matthew; Maestrojuán, Itziar; Platt, Duncan; Brewster, Nick; Viegas, Colin; Alderman, Byron; Ellison, Brian N.

    2016-05-01

    TeraSCREEN is an EU FP7 Security project aimed at developing a combined active, with frequency channel centered at 360 GHz, and passive, with frequency channels centered at 94, 220 and 360 GHz, imaging system for border controls in airport and commercial ferry ports. The system will include automatic threat detection and classification and has been designed with a strong focus on the ethical, legal and practical aspects of operating in these environments and with the potential threats in mind. Furthermore, both the passive and active systems are based on array receivers with the active system consisting of a 16 element MIMO FMCW radar centered at 360 GHz with a bandwidth of 30 GHz utilizing a custom made direct digital synthesizer. The 16 element passive receiver system at 360 GHz uses commercial Gunn diode oscillators at 90 GHz followed by custom made 90 to 180 GHz frequency doublers supplying the local oscillator for 360 GHz sub-harmonic mixers. This paper describes the development of the passive antenna module, local oscillator chain, frequency mixers and detectors used in the passive receiver array of this system. The complete passive receiver chain is characterized in this paper.

  7. 1,2-Dichloropropane

    Integrated Risk Information System (IRIS)

    1,2 - Dichloropropane ; CASRN 78 - 87 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  8. 1,2-Dibromoethane

    Integrated Risk Information System (IRIS)

    1,2 - Dibromoethane ; CASRN 106 - 93 - 4 ( 07 / 29 / 2004 ) Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessment

  9. 1,2-Dichlorobenzene

    Integrated Risk Information System (IRIS)

    1,2 - Dichlorobenzene ; CASRN 95 - 50 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  10. 1,2-Dichloroethane

    Integrated Risk Information System (IRIS)

    1,2 - Dichloroethane ; CASRN 107 - 06 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  11. 1,2-Diphenylhydrazine

    Integrated Risk Information System (IRIS)

    1,2 - Diphenylhydrazine ; CASRN 122 - 66 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcin

  12. Purification and some properties of 2-halobenzoate 1,2-dioxygenase, a two-component enzyme system from Pseudomonas cepacia 2CBS.

    PubMed Central

    Fetzner, S; Müller, R; Lingens, F

    1992-01-01

    The two components of the inducible 2-halobenzoate 1,2-dioxygenase from Pseudomonas cepacia 2CBS were purified to homogeneity. Yellow component B is a monomer (Mr, 37,500) with NADH-acceptor reductase activity. Ferricyanide, 2,6-dichlorophenol indophenol, and cytochrome c acted as electron acceptors. Component B was identified as an iron-sulfur flavoprotein containing 0.8 mol of flavin adenine dinucleotide, 1.7 mol of iron, and 1.7 mol of acid-labile sulfide per mol of enzyme. The isoelectric point was estimated to be pH 4.2. Component B was reduced by the addition of NADH. Red-brown component A (Mr, 200,000 to 220,000) is an iron-sulfur protein containing 5.8 mol of iron and 6.0 mol of acid-labile sulfide. The isoelectric point was within the range of pH 4.5 to 5.3. Component A could be reduced by dithionite or by NADH plus catalytic amounts of component B. Component A consisted of nonidentical subunits alpha (Mr, 52,000) and beta (Mr, 20,000). It contained approximately equimolar amounts of alpha and beta, and cross-linking studies suggested an alpha 3 beta 3 subunit structure of component A. The NADH- and Fe(2+)-dependent enzyme system was named 2-halobenzoate 1,2-dioxygenase, because it catalyzes the conversion of 2-fluoro-, 2-bromo-, 2-chloro-, and 2-iodobenzoate to catechol. 2-Halobenzoate 1,2-dioxygenase exhibited a very broad substrate specificity, but benzoate analogs with electron-withdrawing substituents at the ortho position were transformed preferentially. Images PMID:1370284

  13. Distinct roles of two cytoplasmic thioredoxin reductases (Trr1/2) in the redox system involving cysteine synthesis and host infection of Beauveria bassiana.

    PubMed

    Zhang, Long-Bin; Tang, Li; Ying, Sheng-Hua; Feng, Ming-Guang

    2016-12-01

    Two thioredoxin (Trx) reductases (Trr1/2) are known to play overlapping roles in the yeast Trx-Trr redox system but are generally unexplored in filamentous fungi, which possess multiple Trx homologues. This study seeks to characterize the functions of Trr1 and Trr2 in Beauveria bassiana, a filamentous fungal insect pathogen, and to probe their Trx partners. Both Trr1 and Trr2 were evidently localized in the cytoplasm of B. bassiana, unlike the two yeast homologues that have been reported to localize in the cytoplasm and mitochondria, respectively. Most of the six trx genes were greatly upregulated at the transcriptional level in the absence of trr1 instead of trr2 in B. bassiana, in which the trr1/2 double deletion failed in many attempts. Deletion of trr1 resulted in increased Trx activity, severe cysteine auxotrophy, and drastically reduced activities of peroxidases and superoxide dismutases under normal or oxidative conditions despite little change in catalase activity. Such changes disappeared in the absence of trr2 and were completely restored by complementation of trr1/2 or overexpression of trx1/6 in the Δtrr1 mutant, but were not restored at all by overexpression of trx2/3/4/5 or trr2 in the same mutant. All of these mutants exhibited similar trends of changes in the antioxidant response, conidiation, germination, thermotolerance, UV-B resistance, and virulence. Taken together, the findings indicate that Trr1 could reduce Trx2-5 and hence dominate the intracellular redox state, profoundly affecting the potential of B. bassiana against arthropod pests. Trr2 could reduce Trx1/6 but function only in the absence of Trr1.

  14. 324GHz CMOS VCO Using Linear Superimposition Technique

    NASA Technical Reports Server (NTRS)

    Daquan, Huang; LaRocca, Tim R.; Samoska, Lorene A; Fung, Andy; Chang, Frank

    2007-01-01

    Terahertz (frequencies ranged from 300GHz to 3THz) imaging and spectroscopic systems have drawn increasing attention recently due to their unique capabilities in detecting and possibly analyzing concealed objects. The generation of terahertz signals is nonetheless nontrivial and traditionally accomplished by using either free-electron radiation, optical lasers, Gunn diodes or fundamental oscillation by using III-V based HBT/HEMT technology[1-3]... We have substantially extended the operation range of deep-scaled CMOS by using a linear superimposition method, in which we have realized a 324GHz VCO in 90nm digital CMOS with 4GHz tuning range under 1V supply voltage. This may also pave the way for ultra-high data rate wireless communications beyond that of IEEE 802.15.3c and reach data rates comparable to that of fiber optical communications, such as OC768 (40Gbps) and beyond.

  15. Low-noise 6-8 GHz receiver

    NASA Astrophysics Data System (ADS)

    Pandian, J. D.; Baker, L.; Cortes, G.; Goldsmith, P. F.; Deshpande, A. A.; Ganesan, R.; Hagen, J.; Locke, L.; Wadefalk, N.; Weinreb, S.

    2006-12-01

    The combination of the traveling wave OMT device and the ultra-low-noise MMIC amplifiers has allowed us to develop a broadband 6-8 GHz receiver with a noise temperature of around 10 K. The combination of receiver noise and the additional noise contributions by the telescope optics gives an overall receiver temperature of around 28 K and 34 K in the two polarizations. The large collecting area of the telescope gives rise to a system equivalent flux density of around 4.5 Jy at 7 GHz.

  16. A 32 GHz microstrip array antenna for microspacecraft application

    NASA Technical Reports Server (NTRS)

    Huang, J.

    1994-01-01

    JPL/NASA is currently developing microspacecraft systems for future deep space applications. One of the frequency bands being investigated for microspacecraft is the Ka-band (32 GHz), which can be used with smaller equipment and provides a larger bandwidth. This article describes the successful development of a circularly polarized microstrip array with 28 dBic of gain at 32 GHz. This antenna, which is thin, flat, and small, can be surface-mounted onto the microspacecraft and, hence, takes very little volume and mass of the spacecraft. The challenges in developing this antenna are minimizing the microstrip antenna's insertion loss and maintaining a reasonable frequency bandwidth.

  17. An oil-absorber-bioscrubber system to stabilize biotreatment of pollutants present in waste gas. Fluctuating loads of 1,2-dichloroethane.

    PubMed

    Koutinas, Michalis; Martin, James; Peeva, Ludmila G; Mantalaris, Athanasios; Livingston, Andrew G

    2006-01-15

    Biotreatment technologies offer a cost-effective and efficient method for dealing with point-source releases of solvents. However, a major problem hampering these technologies is the fluctuating pollutant loads, which is especially critical for inhibitory pollutants. Provision of biotreatment systems able to cope with this problem is a significant technological and environmental challenge. This study investigates the potential for an absorber to act as buffer for shock loadings of inhibitory pollutants in waste-gas streams undergoing biological treatment. 1,2-Dichloroethane (DCE) was used as an example of a toxic and inhibitory organic pollutant. The stability of a combined oil-absorber-bioscrubber (OAB) system was compared to that of a bioscrubber only (BO) system when each was subjected to shock loads of DCE. The BO system was inoculated with Xanthobacter autotrophicus strain GJ10 and was submitted to sharp, sequential pulses in DCE inlet load, which caused system instability. Complete inhibition of the BO process occurred for a 3 h DCE pulse, leading to 9125 g of DCE m(-3)bioscrubber total organic discharged (TODDCE). Following the pulse, fluorescence in situ hybridization (FISH) showed that the active strain GJ10 was effectively washed-out. In contrast, the performance of the OAB system was stable during DCE shock loads. The carbon dioxide production remained stable, and low levels of effluent DCE and total organic carbon concentrations were found. For the 3 h pulse TODDCE was only 173 g of DCE m(-3)bioscrubber, and FISH indicated that the GJ10 strain remained active. We conclude that the OAB system offers an effective solution to the biological treatment of waste-gas containing fluctuating pollutant concentrations.

  18. Investigations Into Accumulator 4-8 GHz Pickup Loop / Combiner Board Performance

    SciTech Connect

    Vander Meuler, D.; /Fermilab

    2000-04-17

    A set of pickup measurements performed in August of 1999 (see Pbar note 618) indicated problems with the pickup sensitivity for frequencies above {approx}4.8 GHz. This note describes the effort made to determine if the problems with system performance were due to the design of the 4-8 GHz circuit board.

  19. New space research frequency band proposals in the 20- to 40.5-GHz range

    NASA Technical Reports Server (NTRS)

    Bishop, D. F.

    1991-01-01

    Future space research communications systems may require spectra above 20 GHz. Frequency bands above 20 GHz are identified that are suitable for space research. The selection of the proper bands depends on consideration of interference with other radio services, adequate bandwidths, link performance, and technical requirements for practical implementation.

  20. Characteristics of ocular temperature elevations after exposure to quasi- and millimeter waves (18-40 GHz)

    NASA Astrophysics Data System (ADS)

    Kojima, Masami; Suzuki, Yukihisa; Tsai, Cheng-Yu; Sasaki, Kensuke; Wake, Kanako; Watanabe, Soichi; Taki, Masao; Kamimura, Yoshitsugu; Hirata, Akimasa; Sasaki, Kazuyuki; Sasaki, Hiroshi

    2015-04-01

    In order to investigate changes in ocular temperature in rabbit eyes exposed to different frequencies (18 to 40 GHz) of quasi-millimeter waves, and millimeter waves (MMW). Pigmented rabbits were anesthetized with both general and topical anesthesia, and thermometer probes (0.5 mm in diameter) were inserted into their cornea (stroma), lens (nucleus) and vitreous (center of vitreous). The eyes were exposed unilaterally to 200 mW/cm2 by horn antenna for 3 min at 18, 22 and 26.5 GHz using a K band exposure system or 26.5, 35 and 40 GHz using a Ka band exposure system. Changes in temperature of the cornea, lens and vitreous were measured with a fluoroptic thermometer. Since the ocular temperatures after exposure to 26.5 GHz generated by the K band and Ka band systems were similar, we assumed that experimental data from these 2 exposure systems were comparable. The highest ocular temperature was induced by 40 GHz MMW, followed by 35 GHz. The 26.5 and 22 GHz corneal temperatures were almost the same. The lowest temperature was recorded at 18 GHz. The elevation in ocular temperature in response to exposure to 200 mW/cm2 MMW is dependent on MMW frequency. MMW exposure induced heat is conveyed not only to the cornea but also the crystalline lens.

  1. Erratum: Factors predicting non-sentinel lymph node metastasis in T1-2 invasive breast cancer with 1-2 axillary sentinel lymph node metastases:Presentation of Ondokuz Mayis scoring system.

    PubMed

    Kuru, Bekir; Sullu, Yurdanur; Yuruker, Savas; Koray Bayrak, Ilkay; Ozen, Necati

    2016-01-01

    In this article published in Volume 21, issue 5, the Results section of the Pubmed abstract appeared as: "There were 68 (33%) and 108 (52%) patients with a the score of ? 4 (predicted probability of ?10%) with a false negative rate (FNR% of 4.4%, and ?5 (predicted probability of ?15%) with a FNR of 7.4%, respectively. The area under the curve (AUC) value for the Ondokuz Mayis scoring system was 0.88 (95% CI 0.83-0.93%)." The correct Results section of the abstract is: "There were 68 (33%) and 108 (52%) patients with a the score of ≤4 (predicted probability of ≤10%) with a false negative rate (FNR) of 4.4%, and ≤5 (predicted probability of ≤15%) with a FNR of 7.4%, respectively. The area under the curve (AUC) value for the Ondokuz Mayis scoring system was 0.88 (95% CI 0.83-0.93)." This error appeared only in the PubMed database and not in the print form of the Journal.

  2. Cross-impact study of foreign satellite communications on NASA's 30/20 GHz program

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A comprehensive traffic demand forecast and a scenario for the transition process from current satellite systems to more advanced systems of the 1990's are presented. Systems configurations with and without the use of 30/20 GHz are described and these two alternatives are compared. It is concluded that: (1) the use of 30/20 GHz will result in increased satellite capacity, which will be needed to satisfy demand; (2) the use of 30/20 GHz will decrease the transmission cost, especially for broadband communications; (3) in some areas, particularly Europe and Japan but also the U.S., 30/20 GHz is the only available frequency band for customer premise Earth stations because of the dense terrestrial microwave networks; and (4) the development of 30/20 GHz technology will improve U.S. markets for equipment and satellites in many world regions.

  3. Cross-impact study of foreign satellite communications on NASA's 30/20 GHz program

    NASA Astrophysics Data System (ADS)

    1980-08-01

    A comprehensive traffic demand forecast and a scenario for the transition process from current satellite systems to more advanced systems of the 1990's are presented. Systems configurations with and without the use of 30/20 GHz are described and these two alternatives are compared. It is concluded that: (1) the use of 30/20 GHz will result in increased satellite capacity, which will be needed to satisfy demand; (2) the use of 30/20 GHz will decrease the transmission cost, especially for broadband communications; (3) in some areas, particularly Europe and Japan but also the U.S., 30/20 GHz is the only available frequency band for customer premise Earth stations because of the dense terrestrial microwave networks; and (4) the development of 30/20 GHz technology will improve U.S. markets for equipment and satellites in many world regions.

  4. Operation of the SUPARAMP at 33GHz

    NASA Technical Reports Server (NTRS)

    Chiao, R. Y.; Parrish, P. T.

    1975-01-01

    A 9mm degenerate parametric amplifier was constructed using a linear, series array of unbiased Josephson junctions as the active, nonlinear element. A balanced diode mixer was used as a synchronous detector, with a single source serving both as the pump and as the mixer local oscillator. A stable, net gain of 15 dB in an instantaneous bandwith (FWHM) of 3.4 GHz was achieved. A system noise temperature of 220 K + or - 5 K (DSB) was measured with a SUPARAMP contribution of only 20 K x or - 10 K. Output saturation was observed and complicates the interpretation of the noise temperature measurements and may render them upper limits. A comparison was made with the results of an earlier 3 cm suparamp. The data is in substantial agreement with theoretical predictions.

  5. The HUT 93 GHz airborne imaging radiometer

    SciTech Connect

    Kemppinen, M.; Auer, T.; Pallonen, J.; Mononen, I.

    1996-10-01

    The 93 GHz conically scanning dual-channel Airborne Imaging Radiometer, AIR-93, was completed at the Helsinki University of Technology in April 1995. It was designed for Bell JetRanger platform, but modified to be compatible with the HUT remote sensing airplane in few weeks after the completion. Test and service flight experiences aboard both platforms brought up improvement ideas, whose realization was considered easier aboard the HUT airplane. The new features include (a) rebuilding the electronics unit,(b) the use of an attitude-dGPS instrument to produce gyro data for radiometer beam active stabilization, (c) an improved version of the airborne, liquid nitrogen cooled cold calibration target, and (d) the digital, computationally stabilized, position oriented optical comparison image system. 9 refs., 7 figs., 1 tab.

  6. The 5/15 GHz scattering study

    NASA Astrophysics Data System (ADS)

    Crane, Robert K.

    1991-05-01

    Received signal level and multipath delay spread measurements were made at 5 and 16 GHz on a 161 km tropospheric scatter path over moderately rough terrain from Prospect Hill in Waltham, MA to Mt. Tug in Lebanon, NH. The measurement campaign spanned the summer months of May through Aug. 1989. The signal level data were processed to obtain hourly median values for the estimation of the cumulative distribution function (cdf) of received signal level for use in troposcatter communication system design. Multipath delay spread observations were made at the higher frequency. These data were also processed to obtain the sample cdf of the hourly median values of the two sigma multipath delay spread estimates.

  7. Measurement of homonuclear magnetic dipole-dipole interactions in multiple 1/2-spin systems using constant-time DQ-DRENAR NMR.

    PubMed

    Ren, Jinjun; Eckert, Hellmut

    2015-11-01

    A new pulse sequence entitled DQ-DRENAR (Double-Quantum based Dipolar Recoupling Effects Nuclear Alignment Reduction) was recently described for the quantitative measurement of magnetic dipole-dipole interactions in homonuclear spin-1/2 systems involving multiple nuclei. As described in the present manuscript, the efficiency and performance of this sequence can be significantly improved, if the measurement is done in the constant-time mode. We describe both the theoretical analysis of this method and its experimental validation of a number of crystalline model compounds, considering both symmetry-based and back-to-back (BABA) DQ-coherence excitation schemes. Based on the combination of theoretical analysis and experimental results we discuss the effect of experimental parameters such as the chemical shift anisotropy (CSA), the spinning rate, and the radio frequency field inhomogeneity upon its performance. Our results indicate that constant-time (CT-) DRENAR is a method of high efficiency and accuracy for compounds with multiple homonuclear spin systems with particular promise for the analysis of stronger-coupled and short T2 spin systems. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Observation of anomalous dielectric properties in low-dimensional spin 1/2 α-Cu2V2O7 magnetic system

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Jen; Chandrasekhar, Kakarla-Devi; Fan, Ko-Jung; Lin, Jiunn-Yuan; Lee, Jenn-Min; Chen, Jin-Ming; Yang, Hung-Duen

    Recently, low-dimensional magnetic systems have received much attention from both theoretical and experimental physics point of view due to their fascinating physical properties. In general, Cu2V2O7 can stabilize at least two sibling polymorphs named as α and β phases. In α phase, Cu2V2O7 crystallized in orthorhombic with Fdd2 space groups. The complex magnetic exchange interaction between the Cu-O-Cu ion within the intra and interchain creates the Dzyaloshinskii-Moriya interaction that leads to weak ferromagnetism below the magnetic transition temperature TN = 34 K. In this study, we present the results of multiple dielectric anomalies observed in the low dimensional spin 1/2 α-Cu2V2O7 magnetic system. The observed dielectric signatures can be ascribed to the complex magnetic interaction α-Cu2V2O7 system. Further, the chemical doping effect on the magnetic and multiferroic properties of α-Cu2V2O7 is underway.

  9. Measurement of homonuclear magnetic dipole-dipole interactions in multiple 1/2-spin systems using constant-time DQ-DRENAR NMR

    NASA Astrophysics Data System (ADS)

    Ren, Jinjun; Eckert, Hellmut

    2015-11-01

    A new pulse sequence entitled DQ-DRENAR (Double-Quantum based Dipolar Recoupling Effects Nuclear Alignment Reduction) was recently described for the quantitative measurement of magnetic dipole-dipole interactions in homonuclear spin-1/2 systems involving multiple nuclei. As described in the present manuscript, the efficiency and performance of this sequence can be significantly improved, if the measurement is done in the constant-time mode. We describe both the theoretical analysis of this method and its experimental validation of a number of crystalline model compounds, considering both symmetry-based and back-to-back (BABA) DQ-coherence excitation schemes. Based on the combination of theoretical analysis and experimental results we discuss the effect of experimental parameters such as the chemical shift anisotropy (CSA), the spinning rate, and the radio frequency field inhomogeneity upon its performance. Our results indicate that constant-time (CT-) DRENAR is a method of high efficiency and accuracy for compounds with multiple homonuclear spin systems with particular promise for the analysis of stronger-coupled and short T2 spin systems.

  10. Systemic injection of TLR1/2 agonist improves adoptive antigen-specific T cell therapy in glioma-bearing mice.

    PubMed

    Zhang, Yufei; Luo, Feifei; Li, Anning; Qian, Jiawen; Yao, Zhenwei; Feng, Xiaoyuan; Chu, Yiwei

    2014-09-01

    Adoptive immunotherapy is an attractive strategy for glioma treatment. However, some obstacles still need be overcome. In this study, GL261-bearing mice treated with adoptively transferred antigen-specific T cells and systemic injection of bacterial lipoprotein (BLP), a TLR1/2 agonist, got a long-term survival and even immune protection. By analyzing adoptive T cells, it was found that BLP maintained T cell survival, proliferation and anti-tumor efficacy in the brains of tumor-bearing hosts. Moreover, tumor microenvironment was modified by up-regulating IFN-γ-secreting CD8+ T cells and down-regulating MDSC, which might be related with high CXCL10 and low CCL2 expression. In addition, TLR2 deficiency abrogated therapeutic effect with increased MDSC accumulation and decreased IFN-γ-secreting CD8+ T cells in the brains. Thus, the systemic injection of BLP could improve the adoptive T cell therapy by maintaining T cell persistence, modifying the tumor microenvironment and even inducing systemic anti-tumor immunity, which might offer a clinically promising immunotherapeutic strategy for glioma.

  11. A 150 GHz Receiver Module for Astronomical Observations

    NASA Astrophysics Data System (ADS)

    Voll, Patricia; Lau, J.; Sieth, M.; Church, S.; Samoska, L. A.; Kangaslahti, P. P.; Soria, M.; Gaier, T. C.; Van Winkle, D.; Tantawi, S.

    2011-01-01

    A compact, wide-band, heterodyne amplifier module has been designed to operate in the 150 GHz atmospheric window using High Electron Mobility Transistor (HEMT) amplifier technology. This frequency range is important for many astrophysical science applications, including spectral line studies, separating the cosmic microwave background (CMB) radiation from foregrounds, and detecting the hot gas around galaxy clusters using the Sunyaev-Zeldovich effect. HEMT-based receiver arrays with excellent noise and scalability are already being manufactured around 100 GHz, but recent advances have made it possible to extend this technology to even higher frequencies. The prototype 150 GHz module housing utilizes Monolithic Millimeter-Wave Integrated Circuit (MMIC) InP Low Noise Amplifiers (LNAs). These amplifiers, along with a second harmonic mixer, bias circuitry, and connectors, are contained in a single, split-block housing approximately one inch cubed in size. Preliminary cryogenic tests have measured a system noise temperature of 150 K over a bandwidth of 25 GHz with a minimum noise temperature of less than 100 K at 168 GHz. The minimum noise temperature is less than 100 K at 168 GHz. Module improvements for the second phase are expected to reduce the noise temperature to the minimum allowed by the device limit. Development of a 4-element array to demonstrate the scalability of these receivers is currently underway, and will serve as a prototype for much larger, 100-element arrays for astrophysical applications. In the future, a space mission incorporating an array of these modules could be used to detect the curl modes (B-modes) of the CMB polarization, which is important for the search for the signature of inflation.

  12. 2-GHz frequency-domain fluorometer

    NASA Astrophysics Data System (ADS)

    Lakowicz, Joseph R.; Laczko, Gabor; Gryczynski, Ignacy

    1986-10-01

    We developed a frequency-domain fluorometer which operates from 4 to 2000 MHz. The modulated excitation is provided by the harmonic content of a laser pulse train (3.76 MHz, 5 ps) from a synchronously pumped and cavity dumped dye laser. The phase angle and modulation of the emission are measured with a microchannel-plate photomultiplier (PMT). Cross-correlation detection is performed outside the PMT. The high-frequency signals for cross correlation were obtained by multiplication of the output from a 500-MHz frequency synthesizer. The performance was verified in several ways, including measurement of known time delays and examination of standard fluorophores. The detector displayed no detectable color effect, with the 300-600-nm difference being less than 5 ps. The precision of the measurements is adequate to detect differences of 20 ps for decay times of 500 ps. A correlation time of 53 ps was found for indole in water at 20 °C. The shortest correlation time we measured was 15 ps for indole in methanol/water (75/25) at 40 °C. Also, the 2-GHz data reveal the time-dependent ((t)1/2) terms found in the presence of collisional quenching. The degree of random error is about 0.3° of phase and 0.005 in modulation throughout the frequency range.

  13. American Telephone and Telegraph System V/MLS Release 1.1.2 Running on Unix System V Release 3.1.1

    DTIC Science & Technology

    1989-10-18

    Cartridge bss NOT USED Available Expansion RAM Card 800000 NVRAM FEE001 FIGURE 2. THE 630 MTG MEMORY LAYOUT 19 October 18, 1989 Final Evaluation...that the firmware can be modified and thus grow in size. The Non-Volatile Read-Access Memory ( NVRAM ) is battery backed and holds terminal setup data...two cases: either the root or firmware password is lost, or the system battery is weak and parts of the system Non-Volatile RAM ( NVRAM ) become

  14. TOUGH+HYDRATE v1.2 User's Manual: A Code for the Simulation of System Behavior in Hydrate-Bearing Geologic Media

    SciTech Connect

    Moridis, George J.; Kowalsky, Michael B.; Pruess, Karsten

    2012-08-01

    TOUGH+HYDRATE v1.2 is a code for the simulation of the behavior of hydratebearing geologic systems, and represents the second update of the code since its first release [Moridis et al., 2008]. By solving the coupled equations of mass and heat balance, TOUGH+HYDRATE can model the non-isothermal gas release, phase behavior and flow of fluids and heat under conditions typical of common natural CH4-hydrate deposits (i.e., in the permafrost and in deep ocean sediments) in complex geological media at any scale (from laboratory to reservoir) at which Darcy’s law is valid. TOUGH+HYDRATE v1.2 includes both an equilibrium and a kinetic model of hydrate formation and dissociation. The model accounts for heat and up to four mass components, i.e., water, CH4, hydrate, and water-soluble inhibitors such as salts or alcohols. These are partitioned among four possible phases (gas phase, liquid phase, ice phase and hydrate phase). Hydrate dissociation or formation, phase changes and the corresponding thermal effects are fully described, as are the effects of inhibitors. The model can describe all possible hydrate dissociation mechanisms, i.e., depressurization, thermal stimulation, salting-out effects and inhibitor-induced effects. TOUGH+HYDRATE is a member of TOUGH+, the successor to the TOUGH2 [Pruess et al., 1991] family of codes for multi-component, multiphase fluid and heat flow developed at the Lawrence Berkeley National Laboratory. It is written in standard FORTRAN 95/2003, and can be run on any computational platform (workstation, PC, Macintosh) for which such compilers are available.

  15. Teleportation of a 3-dimensional GHZ State

    NASA Astrophysics Data System (ADS)

    Cao, Hai-Jing; Wang, Huai-Sheng; Li, Peng-Fei; Song, He-Shan

    2012-05-01

    The process of teleportation of a completely unknown 3-dimensional GHZ state is considered. Three maximally entangled 3-dimensional Bell states function as quantum channel in the scheme. This teleportation scheme can be directly generalized to teleport an unknown d-dimensional GHZ state.

  16. Connection between Fermi contours of zero-field electrons and ν =1/2 composite fermions in two-dimensional systems

    NASA Astrophysics Data System (ADS)

    Ippoliti, Matteo; Geraedts, Scott D.; Bhatt, R. N.

    2017-07-01

    We investigate the relation between the Fermi sea (FS) of zero-field carriers in two-dimensional systems and the FS of the corresponding composite fermions which emerge in a high magnetic field at filling ν =1/2 , as the kinetic energy dispersion is varied. We study cases both with and without rotational symmetry and find that there is generally no straightforward relation between the geometric shapes and topologies of the two FSs. In particular, we show analytically that the composite Fermi liquid (CFL) is completely insensitive to a wide range of changes to the zero-field dispersion which preserve rotational symmetry, including ones that break the zero-field FS into multiple disconnected pieces. In the absence of rotational symmetry, we show that the notion of "valley pseudospin" in many-valley systems is generically not transferred to the CFL, in agreement with experimental observations. We also discuss how a rotationally symmetric band structure can induce a reordering of the Landau levels, opening interesting possibilities of observing higher-Landau-level physics in the high-field regime.

  17. Antitumor activity of amidino-substituted benzimidazole and benzimidazo[1,2-a]quinoline derivatives tested in 2D and 3D cell culture systems.

    PubMed

    Brajša, Karmen; Vujasinović, Ines; Jelić, Dubravko; Trzun, Marija; Zlatar, Ivo; Karminski-Zamola, Grace; Hranjec, Marijana

    2016-12-01

    Due to a poor clinical predictive power of 2D cell cultures, standard tool for in vitro assays in drug discovery process, there is increasing interest in developing 3D in vitro cell cultures, biologically relevant assay feasible for the development of robust preclinical anti-cancer drug screening platforms. Herein, we tested amidino-substituted benzimidazoles and benzimidazo[1,2-a]quinolines as a small platform for comparison of antitumor activity in 2D and 3D cell culture systems and correlation with structure-activity relationship. 3D cell culture method was applied on a human cancer breast (SK-BR-3, MDA-MB-231, T-47D) and pancreatic cancer cells (MIA PaCa-2, PANC-1). Results obtained in 2D and 3D models were highly comparable, but in some cases we have observed significant disagreement indicating that some prominent compounds can be discarded in early phase of researching because of compounds with false positive result. To confirm which of cell culture systems is more accurate, in vivo profiling is needed.

  18. Corrosion in quench systems of entrained slagging gasifiers: a laboratory study. Final report. [1 1/4Cr-1/2Mo(T-11)

    SciTech Connect

    Bhattacharyya, S.

    1985-11-01

    The objective of this program was to conduct laboratory autoclave tests simulating environments of the gray water system of an entrained slagging gasifier plant. Five tests (one 200-h and four 1000-h) were conducted using ferritic steel material 1 1/4Cr-1/2Mo (T-11) and 14% silicon cast iron; austenitic stainless steels 304L, 316, 321, and Sanicro 28; duplex stainless steel 2205; and Incoloy 825. In the vapor phase with autoclave solution pH in the 4.5 to 4.8 range, 304L SS, 316 SS, 321 SS, and Incoloy 825 double U-bends suffered significant intergranular SCC. Some crevice-assisted cracking is suspected. Pitting corrosion, as measured by maximum pit depth, may become serious since the rate of growth is not known. At the pit base, preferential dissolution was identified similar to grain- and twin-boundary preferential corrosion. General corrosion of the stainless steels was low, but T-11 and 14% silicon cast iron cannot be used unprotected. High acidic pH (6.2 and 6.4) and lower total chloride levels eliminated SCC problems and reduced pitting and corrosion. Of the two phases in a quench system, the vapor phase poses more danger to the materials of construction, particularly to the internal attachments and extensions where welding is required. 13 refs., 31 figs., 4 tabs.

  19. FINAL REPORT TESTS ON THE DURAMELTER 1200 HLW PILOT MELTER SYSTEM USING AZ-101 HLW SIMULANTS VSL-02R0100-2 REV 1 2/17/03

    SciTech Connect

    KRUGER AA; MATLACK KS; KOT WK; BARDAKCI T; GONG W; D'ANGELO NA; SCHATZ TR; PEGG IL

    2011-12-29

    This document provides the final report on data and results obtained from a series of nine tests performed on the one-third scale DuraMelter{trademark} 1200 (DM1200) HLW Pilot Melter system that has been installed at VSL with an integrated prototypical off-gas treatment system. That system has replaced the DM1000 system that was used for HLW throughput testing during Part B1 [1]. Both melters have similar melt surface areas (1.2 m{sup 2}) but the DM1200 is prototypical of the present RPP-WTP HLW melter design whereas the DM1000 was not. These tests were performed under a corresponding RPP-WTP Test Specification and associated Test Plans. The nine tests reported here were preceded by an initial series of short-duration tests conducted to support the start-up and commissioning of this system. This report is a followup to the previously issued Preliminary Data Summary Reports. The DM1200 system was deployed for testing and confirmation of basic design, operability, flow sheet, and process control assumptions as well as for support of waste form qualification and permitting. These tests include data on processing rates, off-gas treatment system performance, recycle stream compositions, as well as process operability and reliability. Consequently, this system is a key component of the overall HLW vitrification development strategy. The primary objective of the present series of tests was to determine the effects of a variety of parameters on the glass production rate in comparison to the RPP-WTP HL W design basis of 400 kg/m{sup 2}/d. Previous testing on the DMIOOO system [1] concluded that achievement of that rate with simulants of projected WTP melter feeds (AZ-101 and C-106/AY-102) was unlikely without the use of bubblers. As part of those tests, the same feed that was used during the cold-commissioning of the West Valley Demonstration Project (WVDP) HLW vitrification system was run on the DM1000 system. The DM1000 tests reproduced the rates that were obtained at the

  20. Lorentz detuning and tuning system study of 3+1/2cell DC-SC photo-injector for PKU-FEL

    NASA Astrophysics Data System (ADS)

    Xu, Wen-Can; Quan, Sheng-Wen; Zhao, Kui; Zhu, Feng

    2008-03-01

    A 3+1/2cell DC-SC photo-injector for PKU-FEL facility is under development, which is an upgrade design of the successful 1+1/2cell DC-SC photo-injector. The Lorentz detuning and tuning structure for the 3+1/2cell superconducting cavity is presented in this paper. The Lorentz force detuning coefficient is 1.2 Hz/(MV/m)2 with double stiffening rings for the half cell and single stiffening rings between the adjacent TESLA cells. With the special stiffening structure, the 3+1/2cell whole cavity needs only one tuner. The influences of the tuning on frequency shift, field flatness and average gradient are discussed in this paper. The simulation results show that the stiffening rings' design is successful. Supported by Major State Basic Research Development Program of China (2002CB713600)

  1. NucliSens EasyQ HIV-1 V1.2 system: Detection of human plasma-derived background signal.

    PubMed

    van Zyl, G U; Korsman, S N J; Maree, L; Preiser, W

    2010-05-01

    Until recently the NucliSens EasyQ HIV-1 V1.2 system has been used throughout South Africa as part of the national antiretroviral roll-out programme for the monitoring of HIV-1 RNA load in patients on antiretroviral treatment. Shortly after changing to a new assay lot number an increased proportion of patient specimens, showing detectable but low viral loads, was observed (<200 IU/ml). The test runs remained valid as the lysis buffer-only no-template controls (NTCs) remained negative. Contamination with amplification product was excluded. Subsequently the same phenomenon was observed in at least three other South African laboratories across different assay lot numbers. When testing aliquots of plasma, freshly obtained from HIV-negative donors, at two of these laboratories, 33/134 aliquots showed detectable values (range 26-370, median: 64 IU/ml), while all NTCs remained negative. These findings emphasize the importance of appropriate specimen controls in all diagnostic assays. In this case HIV-negative human plasma should be included routinely in addition to NTCs, which would allow rapid detection of a background signal.

  2. Solid state synthesis, structural, physicochemical and optical properties of an inter-molecular compound: 2-hydroxy-1, 2-diphenylethanone-4-nitro-o-phenylenediamine system

    NASA Astrophysics Data System (ADS)

    Rai, U. S.; Singh, Manjeet; Rai, R. N.

    2017-09-01

    The phase diagram of 2-hydroxy-1, 2-diphenylethanone (HDPE)-4-nitro-o-phenylenediamine (NOPDA) system, determined by the thaw-melt method, gives two eutectics E1 (m p = 66.0 °C) and E2 (m p = 155.0 °C) with 0.30 and 0.55 mol fractions of NOPDA, respectively, and an 1:1 inter-molecular compound (IMC) (m p 162.0 °C). This IMC was synthesized by adopting the green synthetic method of solid state reaction. While its formation and structure were confirmed by the X-ray diffraction and spectroscopic methods, the ORTEP view gives mode of crystal packing, C‒H…O, C‒H…N, π-π stacking and the inter-molecular hydrogen bonding in the compound. The single crystal of the IMC shows 53% transmission and emits significantly higher dual fluorescence, and the band gap was computed to be 3.04 eV. The values of solubility of the IMC, measured in the temperature range 304-322 K, satisfy the mole fraction (X) and temperature equation: Xeq= 5.1324 × 10-7 e 0.01356T.

  3. The influence of temperature and pressure on primary mirror surface figure and image quality of the 1.2m colorful Schlieren system

    NASA Astrophysics Data System (ADS)

    Xu, Songbo; Wang, Peng; Chen, Lei; Wang, Jing; Xie, Yong-jun

    2017-02-01

    In this paper, a colorful schlieren system without any protecting windows was introduced which results in that the 1.2m primary mirror would directly be confronted with the pressure and temperature variation from the wind tunnel test. To achieve a good schlieren image under the wind tunnel test working condition of a wide temperature fluctuation range (-10° to 50°) as well as a pressure (2kPa), a new flexible support method of the primary mirror was strategically designed. A finite element model of the primary mirror combined with its supporting structures was built up to approach the surface figure of the primary mirror under the complex working conditions as gravity, temperature variation, and pressure. The schlieren images due to the change of the primary mirror surface figure were simulated by Light-tools software. It was found that the temperature changing and pressure would lead to the variation of the surface figure of the primary mirror surface figure and therefore, results in the changing of the quality of simulated schlieren images.

  4. FIA-automated system used to electrochemically measure nitrite and its interfering chemicals through a 1-2 DAB / Au electrode: gain of sensitivity at upper potentials

    NASA Astrophysics Data System (ADS)

    Almeida, F. L.; dos Santos Filho, S. G.; Fontes, M. B. A.

    2013-03-01

    The measurement of nitrite and its interfering-chemicals (paracetamol, ascorbic acid and uric acid) was performed employing a Flow-injection Analysis (FIA) system, which was automated using solenoid valves and air-pump. It is very important to quantify nitrite from river water, food and biologic fluids due to its antibacterial capacity in moderated concentrations, or its toxicity for human health even at low concentrations (> 20 μmol L-1 in blood fluids). Electrodes of the electrochemical planar sensor were defined by silk-screen technology. The measuring electrode was made from gold paste covered with 1-2 cis Diaminobenzene (DAB), which allowed good selectivity, linearity, repeatability, stability and optimized gain of sensitivity at 0.5 VAg/AgCl Nafion®117 (6.93 μA mol-1 L mm-2) compared to 0.3 VAg/AgCl Nafion® 117. The reference electrode was obtained from silver/palladium paste modified with chloride and covered with Nafion® 117. The auxiliary electrode was made from platinum paste. It was noteworthy that nitrite response adds to the response of the studied interfering-chemicals and it is predominant for concentrations lower than 175 μmol L-1.

  5. 3-Monochloro-1,2-propanediol (3-MCPD) induces apoptosis via mitochondrial oxidative phosphorylation system impairment and the caspase cascade pathway.

    PubMed

    Peng, Xiaoli; Gan, Jing; Wang, Qian; Shi, Zhenqiang; Xia, Xiaodong

    2016-11-30

    3-Monochloro-1,2-propanediol (3-MCPD) is the most toxic chloropropanols compounds in foodstuff which mainly generated during thermal processing. Kidney is one of the primary target organs for 3-MCPD. Using human embryonic kidney cell (HEK293FT) as an in vitro model, we found that 3-MCPD caused concentration-dependent increase in cytoxicity as assessed by dye uptake, lactatedehydrogenase (LDH) leakage and MTT assays. HEK293FT cell treated with 3-MCPD suffered the decrease of mitochondrial membrane potential and the impairment of mitochondrial oxidative phosphorylation system, especially the reduced amount of mRNA expression and protein synthesis of electron transport chain complex II, complex IV, and complex III. More importantly, energy release (ATP synthesis) was significantly inhibited by 3-MCPD resulting from the down regulation expressions of ATP synthase (ATP6 and ATP8), as well as the loss of transmembrane potential required for synthesis of ATP. The decreased ratio of mitochondrial apoptogenic factors Bax/Bcl-2 and the cytochrome-c release from mitochondria to cytosol followed by the activation of apoptotic initiators caspase 9 and apoptotic executioners (caspase 3, caspase 6 and caspase 7) leading to apoptosis. The activation of caspase 8 and caspase 2 implied that there were probably other factors to induce the caspase-dependent apoptosis.

  6. 110 GHz, 1 MW Gyrotron Design Upgrades

    NASA Astrophysics Data System (ADS)

    Cauffman, Steve; Felch, Kevin; Borchard, Philipp; Cahalan, Pat; Chu, Sam; Dubrule, Craig

    1999-11-01

    Communications and Power Industries has incorporated a number of design changes into its most recent series of 110 GHz 1 MW gyrotrons, for use in ECH and ECCD experiments on the DIII-D tokamak. Two development gyrotrons previously installed at DIII-D used a modulating-anode electron gun design and output windows consisting of double-disk face-cooled sapphire on one system and an edge-cooled CVD diamond disk on the other. Three new systems presently in fabrication and test employ (a) a single-anode electron gun to avoid excitation of spurious modes during turn-on and turn-off and to simplify power supply requirements, (b) a modified TE_22,6 cavity to reduce competition from neighboring modes, (c) a two inch aperture edge-cooled CVD diamond window to allow transmission of a 1 MW Gaussian output beam, (d) a superconducting magnet system with a cryo-cooler to reduce liquid helium consumption, and (e) a number of internal and external plumbing simplifications to make cooling system connections more straightforward. Initial test results, if available, will be presented.

  7. Laboratory Heterodyne Spectrometers Operating at 100 and 300 GHZ

    NASA Astrophysics Data System (ADS)

    Maßen, Jakob; Wehres, Nadine; Hermanns, Marius; Lewen, Frank; Heyne, Bettina; Endres, Christian; Graf, Urs; Honingh, Netty; Schlemmer, Stephan

    2017-06-01

    Two new laboratory heterodyne emission spectrometers are presented that are currently used for high-resolution rotational spectroscopy of complex organic molecules. The room temperature heterodyne receiver operating between 80-110 GHz, as well as the SIS heterodyne receiver operating between 270-370 GHz allow access to two very important frequency regimes, coinciding with Bands 3 and 7 of the ALMA (Atacama Large Millimeter Array) telescope. Taking advantage of recent progresses in the field of mm/submm technology, we build these two spectrometers using an XFFFTS (eXtended Fast Fourier Transform Spectrometer) for spectral acquisition. The instantaneous bandwidth is 2.5 GHz in a single sideband, spread over 32768 channels. Thus, the spectral resolution is about 76 kHz per channel and thus comparable to high resolution spectra from telescopes. Both receivers are operated in double sideband mode resulting in a total instantaneous bandwidth of 5 GHz. The system performances, in particular the noise temperatures and stabilities are presented. Proof-of-concept is demonstrated by showing spectra of methyl cyanide obtained with both spectrometers. While the transition frequencies for this molecule are very well known, intensities of those transitions can also be determined with high accuracy using our new instruments. This additional information shall be exploited in future measurements to improve spectral predictions for astronomical observations. Other future prospects concern the study of more complex organic species, such as ethyl cyanide. These aspects of the new instruments as well as limitations of the two distinct receivers will be discussed.

  8. Locoregional Recurrence Risk for Patients With T1,2 Breast Cancer With 1-3 Positive Lymph Nodes Treated With Mastectomy and Systemic Treatment

    SciTech Connect

    McBride, Andrew; Allen, Pamela; Woodward, Wendy; Kim, Michelle; Kuerer, Henry M.; Drinka, Eva Katherine; Sahin, Aysegul; Strom, Eric A.; Buzdar, Aman; Valero, Vicente; Hortobagyi, Gabriel N.; Hunt, Kelly K.; Buchholz, Thomas A.

    2014-06-01

    Purpose: Postmastectomy radiation therapy (PMRT) has been shown to benefit breast cancer patients with 1 to 3 positive lymph nodes, but it is unclear how modern changes in management have affected the benefits of PMRT. Methods and Materials: We retrospectively analyzed the locoregional recurrence (LRR) rates in 1027 patients with T1,2 breast cancer with 1 to 3 positive lymph nodes treated with mastectomy and adjuvant chemotherapy with or without PMRT during an early era (1978-1997) and a later era (2000-2007). These eras were selected because they represented periods before and after the routine use of sentinel lymph node surgery, taxane chemotherapy, and aromatase inhibitors. Results: 19% of 505 patients treated in the early era and 25% of the 522 patients in the later era received PMRT. Patients who received PMRT had significantly higher-risk disease features. PMRT reduced the rate of LRR in the early era cohort, with 5-year rates of 9.5% without PMRT and 3.4% with PMRT (log-rank P=.028) and 15-year rates 14.5% versus 6.1%, respectively; (Cox regression analysis: adjusted hazard ratio [AHR] 0.37, P=.035). However, PMRT did not appear to benefit patients treated in the later cohort, with 5-year LRR rates of 2.8% without PMRT and 4.2% with PMRT (P=.48; Cox analysis: AHR 1.41, P=.48). The most significant factor predictive of LRR for the patients who did not receive PMRT was the era in which the patient was treated (AHR 0.35 for later era, P<.001). Conclusion: The risk of LRR for patients with T1,2 breast cancer with 1 to 3 positive lymph nodes treated with mastectomy and systemic treatment is highly dependent on the era of treatment. Modern treatment advances and the selected use of PMRT for those with high-risk features have allowed for identification of a cohort at very low risk for LRR without PMRT.

  9. Spacecraft IF switch matrix for wideband service applications in 30/20 GHz communications satellite systems: Proof-of-concept model, executive summary

    NASA Technical Reports Server (NTRS)

    Ho, P. T.; Coban, E.; Pelose, J.

    1983-01-01

    The design and development of a unique coupler crossbar 20 x 20 microwave switch matrix are described. The test results of the proof of concept model that meets the requirements for a high speed satellite switched, time division multiple access (SS-TDMA) system are presented.

  10. High power testing of a 17 GHz photocathode RF gun

    SciTech Connect

    Chen, S.C.; Danly, B.G.; Gonichon, J.

    1995-12-31

    The physics and technological issues involved in high gradient particle acceleration at high microwave (RF) frequencies are under study at MIT. The 17 GHz photocathode RF gun has a 1 1/2 cell ({pi} mode) room temperature cooper cavity. High power tests have been conducted at 5-10 MW levels with 100 ns pulses. A maximum surface electric field of 250 MV/m was achieved. This corresponds to an average on-axis gradient of 150 MeV/m. The gradient was also verified by a preliminary electron beam energy measurement. Even high gradients are expected in our next cavity design.

  11. Exact Product Operator Evolution of Weakly Coupled Spin- {1}/{2} I mS n Systems during Arbitrary RF Irradiation of the I Spins

    NASA Astrophysics Data System (ADS)

    Skinner, Thomas E.; Bendall, M. Robin

    1999-12-01

    In this article, we consider the evolution of weakly coupled ImSn systems of spin-{1}/{2} nuclei during arbitrary RF irradiation of the I spins. Exact solutions are presented for the time dependence of the density operator in terms of its constituent product operator components for a complete set of initial states derived from polarization of either the I or the S spin. The solutions extend the range of applications that are accessible to the product operator formalism and its associated vector picture of nuclear spin evolution. This marriage of quantum mechanics and a literal vector description of spin dynamics during RF irradiation supports physical intuition and has led to simple pulses for selective coherence transfer, among other new applications. The evolution of initial states that are free of transverse S-spin components can be described by classical precession of the I-spin components about effective fields defined by the interaction between the coupling and RF fields. Although there is no analogue involving classical rotations for the evolution of initial states composed of Sx or Sy, a vector description is still possible, and the solutions completely characterize the nature of J-coupling modulation during RF pulses. We emphasize the Cartesian product operator basis in the present treatment, but the solutions are readily obtained in any other basis that might prove suitable in analyzing an experiment. For a system of N coupled spins, standard exact methods involving diagonalization and multiplication of the 2N × 2N matrices that represent the system require on the order of (2N)3 operations to calculate the system response to a general RF waveform at each point in the time domain. By contrast, the efficiency of the present method scales linearly with the number of spins. Since the formalism presented also accommodates the absence of either RF irradiation or the coupling, the solutions provide an efficient means of general pulse sequence simulation

  12. NASA 60 GHz intersatellite communication link definition study. Baseline document

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The overall system and component concepts for a 60 GHz intersatellite communications link system (ICLS) are described. The ICLS was designed to augment the capabilities of the current Tracking and Data Relay Satellite System (TDRSS), providing a data rate capacity large enough to accommodate the expected rates for user satellites (USAT's) in the post-1995 timeframe. The use of 60 GHz for the anticipated successor to TDRSS, the Tracking and Data Acquisition System (TDAS), was selected because of current technology development that will enable multigigibit data rates. Additionally, the attenuation of the earth's atmosphere at 60 GHz means that there is virtually no possibility of terrestrially generated interference (intentional or accidental) or terrestrially based intercept. The ICLS includes the following functional areas: (1) the ICLS payload package on the GEO TDAS satellite that communicates simultaneously with up to five LEO USAT's; (2) the payload package on the USAT that communicates with the TDAS satellite; and (3) the crosslink payload package on the TDAS satellite that communicates with another TDAS satellite. Two methods of data relay on-board the TDAS spacecraft were addressed. One is a complete baseband system (demod and remod) with a bi-directional 2 Gbps data stream; the other is a channelized system wherein some of the channels are baseband and others are merely frequency translated before re-transmission. Descriptions of the TDAS antenna, transmitter, receiver, and mechanical designs are presented.

  13. NASA 60 GHz intersatellite communication link definition study. Baseline document

    NASA Astrophysics Data System (ADS)

    1986-09-01

    The overall system and component concepts for a 60 GHz intersatellite communications link system (ICLS) are described. The ICLS was designed to augment the capabilities of the current Tracking and Data Relay Satellite System (TDRSS), providing a data rate capacity large enough to accommodate the expected rates for user satellites (USAT's) in the post-1995 timeframe. The use of 60 GHz for the anticipated successor to TDRSS, the Tracking and Data Acquisition System (TDAS), was selected because of current technology development that will enable multigigibit data rates. Additionally, the attenuation of the earth's atmosphere at 60 GHz means that there is virtually no possibility of terrestrially generated interference (intentional or accidental) or terrestrially based intercept. The ICLS includes the following functional areas: (1) the ICLS payload package on the GEO TDAS satellite that communicates simultaneously with up to five LEO USAT's; (2) the payload package on the USAT that communicates with the TDAS satellite; and (3) the crosslink payload package on the TDAS satellite that communicates with another TDAS satellite. Two methods of data relay on-board the TDAS spacecraft were addressed. One is a complete baseband system (demod and remod) with a bi-directional 2 Gbps data stream; the other is a channelized system wherein some of the channels are baseband and others are merely frequency translated before re-transmission. Descriptions of the TDAS antenna, transmitter, receiver, and mechanical designs are presented.

  14. Distilling perfect GHZ states from two copies of non-GHZ-diagonal mixed states

    NASA Astrophysics Data System (ADS)

    Wang, Xin-Wen; Tang, Shi-Qing; Yuan, Ji-Bing; Zhang, Deng-Yu

    2017-06-01

    It has been shown that a nearly pure Greenberger-Horne-Zeilinger (GHZ) state could be distilled from a large (even infinite) number of GHZ-diagonal states that can be obtained by depolarizing general multipartite mixed states (non-GHZ-diagonal states) through sequences of (probabilistic) local operations and classical communications. We here demonstrate that perfect GHZ states can be extracted, with certain probabilities, from two copies of non-GHZ-diagonal mixed states when some conditions are satisfied. This result implies that it is not necessary to depolarize these entangled mixed states to the GHZ-diagonal type, and that they are better than GHZ-diagonal states for distillation of pure GHZ states. We find a wide class of multipartite entangled mixed states that fulfill the requirements. Moreover, we display that the obtained result can be applied to practical noisy environments, e.g., amplitude-damping channels. Our findings provide an important complementarity to conventional GHZ-state distillation protocols (designed for GHZ-diagonal states) in theory, as well as having practical applications.

  15. Early life exposure to 2.45GHz WiFi-like signals: effects on development and maturation of the immune system.

    PubMed

    Sambucci, Manolo; Laudisi, Federica; Nasta, Francesca; Pinto, Rosanna; Lodato, Rossella; Lopresto, Vanni; Altavista, Pierluigi; Marino, Carmela; Pioli, Claudio

    2011-12-01

    The development of the immune system begins during embryogenesis, continues throughout fetal life, and completes its maturation during infancy. Exposure to immune-toxic compounds at levels producing limited/transient effects in adults, results in long-lasting or permanent immune deficits when it occurs during perinatal life. Potentially harmful radiofrequency (RF) exposure has been investigated mainly in adult animals or with cells from adult subjects, with most of the studies showing no effects. Is the developing immune system more susceptible to the effects of RF exposure? To address this question, newborn mice were exposed to WiFi signals at constant specific absorption rates (SAR) of 0.08 or 4 W/kg, 2h/day, 5 days/week, for 5 consecutive weeks, starting the day after birth. The experiments were performed with a blind procedure using sham-exposed groups as controls. No differences in body weight and development among the groups were found in mice of both sexes. For the immunological analyses, results on female and male newborn mice exposed during early post-natal life did not show any effects on all the investigated parameters with one exception: a reduced IFN-γ production in spleen cells from microwaves (MW)-exposed (SAR 4 W/kg) male (not in female) mice compared with sham-exposed mice. Altogether our findings do not support the hypothesis that early post-natal life exposure to WiFi signals induces detrimental effects on the developing immune system.

  16. Beyond G-band : a 235 GHz InP MMIC amplifier

    NASA Technical Reports Server (NTRS)

    Dawson, Douglas; Samoska, Lorene; Fung, A. K.; Lee, Karen; Lai, Richard; Grundbacher, Ronald; Liu, Po-Hsin; Raja, Rohit

    2005-01-01

    We present results on an InP monolithic millimeter- wave integrated circuit (MMIC) amplifier having 10-dB gain at 235 GHz. We designed this circuit and fabricated the chip in Northrop Grumman Space Technology's (NGST) 0.07- m InP high electron mobility transistor (HEMT) process. Using a WR3 (220-325 GHz) waveguide vector network analyzer system interfaced to waveguide wafer probes, we measured this chip on-wafer for -parameters. To our knowledge, this is the first time a WR3 waveguide on-wafer measurement system has been used to measure gain in a MMIC amplifier above 230 GHz.

  17. Beyond G-band : a 235 GHz InP MMIC amplifier

    NASA Technical Reports Server (NTRS)

    Dawson, Douglas; Samoska, Lorene; Fung, A. K.; Lee, Karen; Lai, Richard; Grundbacher, Ronald; Liu, Po-Hsin; Raja, Rohit

    2005-01-01

    We present results on an InP monolithic millimeter- wave integrated circuit (MMIC) amplifier having 10-dB gain at 235 GHz. We designed this circuit and fabricated the chip in Northrop Grumman Space Technology's (NGST) 0.07- m InP high electron mobility transistor (HEMT) process. Using a WR3 (220-325 GHz) waveguide vector network analyzer system interfaced to waveguide wafer probes, we measured this chip on-wafer for -parameters. To our knowledge, this is the first time a WR3 waveguide on-wafer measurement system has been used to measure gain in a MMIC amplifier above 230 GHz.

  18. Satellites using the 30/20 GHz band

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.

    1980-01-01

    A review of the future options open to satellite system planners focuses attention on the use of the 30/20 GHz band. Very broad bandwidths available, coupled with a primary allocation for fixed satellite service, make the band very attractive. NASA, in concert with the system and service supplier industries, is planning a research and development program aimed at flight demonstration of 30/20 satellite systems which it is hoped will lead to operational system use in the early 1990's. The communication system concepts and the spacecraft systems necessary to support these for operational use in 1990 and beyond are discussed.

  19. Dielectric relaxation in complex systems: quality sensing and dielectric properties of honeydew melons from 10 MHz to 1.8 GHz

    NASA Astrophysics Data System (ADS)

    Nigmatullin, R. R.; Arbuzov, A. A.; Nelson, S. O.; Trabelsi, S.

    2006-10-01

    Based on new data treatment methods, it is possible to identify the fitting function for the complex permittivity ɛ(jω) measured for a complex system representing plant tissues of honeydew melons in the frequency range (107 to 1.8×109 Hz) at 25°C. The identified fitting function contains 9 fitting parameters and well describes the plant tissue permittivity. These parameters vary for different tissues; their correlation behavior with respect to soluble solids content (SSC), tissue density (TD) and moisture content (MC) are found by a new approach based on the statistics of the fractional moments (SFM). These correlation dependencies expressed in the form of correlation functions can be used for quality sensing of different complex systems, in particular, for ripe fruits and vegetables, where direct relationships between molecular and fitting parameters are not easy to find. These correlation functions can be used for practical purposes to construct a desired calibration curve with respect to quality factors, as for example, moisture content or degree of maturity, expressed in terms of SSC value. The discovered common ``universality'' in dielectric behavior of such complex materials as plant tissues opens a possibility to use dielectric spectroscopy as a nondestructive method of control in analysis of electrical behavior (measured in the form of complex permittivity or impedance) for other complex materials.

  20. A co-coculture system reveals the involvement of intercellular pathways as mediators of the lutropin receptor (LHR)-stimulated ERK1/2 phosphorylation in Leydig cells

    PubMed Central

    Shiraishi, Koji; Ascoli, Mario

    2007-01-01

    Co-cultures of lutropin receptor (LHR) positive and negative Leydig cells were used to test the hypothesis that the LHR provokes phosphorylation of the extracellular regulated kinases (ERK1/2) using intracellular and intercellular pathways. Addition of hCG to MA-10 cells (LHR positive) stimulates phosphorylation of the EGF receptor (EGFR) and ERK1/2 whereas addition of hCG to I-10 cells (LHR negative) does not. Addition of hCG to co-cultures of MA-10 and I-10 cells rapidly stimulates the phosphorylation of the EGFR and ERK1/2 in I-10 cells, however. Transfection of interfering constructs show that the LHR-mediated activation of Fyn in MA-10 cells is necessary for the phosphorylation of the EGFR and ERK1/2 in I-10 cells. This pathway can also be demonstrated in MA-10 cells but the phosphorylation of ERK1/2 in MA-10 cells also involves a second pathway mediated by protein kinase A (PKA). We propose that the LHR-mediated stimulation of the ERK1/2 cascade in Leydig cells depends on two independent pathways. One is intracellular and is mediated by PKA. The second is mediated by Fyn and it involves the release of soluble factors that act to phosphorylate the EGFR in an autocrine/paracrine fashion. PMID:17727840

  1. Physical Processes Associated with Heavy Flooding Rainfall in Nashville, Tennessee, and Vicinity during 1-2 May 2010: The Role of an Atmospheric River and Mesoscale Convective Systems

    NASA Astrophysics Data System (ADS)

    Moore, B. J.; Neiman, P. J.; Ralph, F. M.; Barthold, F. E.

    2011-12-01

    A multi-scale analysis is conducted in order to examine the physical processes that resulted in prolonged heavy rainfall and devastating flash flooding across western and central Tennessee and Kentucky on 1-2 May 2010, during which Nashville, Tennessee, received 344.7 mm of rainfall and incurred 11 flood-related fatalities. On the synoptic scale, heavy rainfall was supported by a persistent corridor of strong water vapor transport rooted in the Tropics that was manifested as an atmospheric river (AR). This AR developed as water vapor was extracted from the eastern tropical Pacific and the Caribbean Sea and transported into the central Mississippi Valley by a strong southerly low-level jet (LLJ) positioned between a persistent lee trough along the eastern Mexico coast and a broad, stationary subtropical ridge positioned over the southeastern U.S. and the subtropical Atlantic. The AR, associated with substantial water vapor content and moderate convective available potential energy, supported the successive development of two quasi-stationary mesoscale convective systems (MCSs) on 1 May and 2 May, respectively. These MCSs were both linearly organized and exhibited back building and echo training, processes which afforded the repeated movement of convective cells over the same area of western and central Tennessee and Kentucky, resulting in a narrow band of rainfall totals of 200-400 mm. Mesoscale analyses reveal that the MCSs developed on the warm side of a slow-moving cold front and that the interaction between the southerly LLJ and convectively generated surface outflow boundaries was fundamental for repeatedly generating convection.

  2. The Low Band Observatory (LOBO): Expanding the VLA Low Frequency Commensal System for Continuous, Broad-band, sub-GHz Observations

    NASA Astrophysics Data System (ADS)

    Kassim, Namir E.; Clarke, Tracy E.; Helmboldt, Joseph F.; Peters, Wendy M.; Brisken, Walter; Hyman, Scott D.; Polisensky, Emil; Hicks, Brian

    2015-01-01

    The Naval Research Laboratory (NRL) and the National Radio Astronomy Observatory (NRAO) are currently commissioning the VLA Low Frequency Ionosphere and Transient Experiment (VLITE) on a subset of JVLA antennas at modest bandwidth. Its bounded scientific goals are to leverage thousands of JVLA on-sky hours per year for ionospheric and transient studies, and to demonstrate the practicality of a prime-focus commensal system on the JVLA. Here we explore the natural expansion of VLITE to a full-antenna, full-bandwidth Low Band Observatory (LOBO) that would follow naturally from a successful VLITE experience. The new Low Band JVLA receivers, coupled with the existing primary focus feeds, can access two frequency bands: 4 band (54 - 86 MHz) and P band (236-492 MHz). The 4 band feeds are newly designed and now undergoing testing. If they prove successful then they can be permanently mounted at the primary focus, unlike their narrow band predecessors. The combination of Low Band receivers and fixed, primary-focus feeds could provide continuous, broad-band data over two complimentary low-frequency bands. The system would also leverage the relatively large fields-of-view of ~10 degrees at 4 band, and ~2.5 degrees at P band, coupling an excellent survey capability with a natural advantage for serendipitous discoveries. We discuss the compelling science case that flows from LOBO's robust imaging and time domain capabilities coupled with thousands of hours of wide-field, JVLA observing time each year. We also touch on the possibility to incorporate Long Wavelength Array (LWA) stations as additional 'dishes' through the LOBO backend, to improve calibration and sensitivity in LOBO's 4 band.

  3. Small-signal characterization and modelling of 55 nm SiGe BiCMOS HBT up to 325 GHz

    NASA Astrophysics Data System (ADS)

    Deng, Marina; Quémerais, Thomas; Bouvot, Simon; Gloria, Daniel; Chevalier, Pascal; Lépilliet, Sylvie; Danneville, François; Dambrine, Gilles

    2017-03-01

    This paper presents a small-signal characterization work on a recently developed 55 nm SiGe BiCMOS technology from STMicroelectronics. The SiGe HBT from a prototype BiCMOS 55 nm process was investigated up to 325 GHz. The full S-parameters from DC to 325 GHz under multiple bias conditions are presented for the first time for a SiGe HBT. A usual and simple approach for the off-wafer calibration associated to an on-wafer de-embedding procedure was used and remained valid up to 325 GHz thanks to a size reduction of the test structures. The extracted 300/325 GHz fT/fMAX couple, reached at 14 mA/μm2 collector density and 1.2 V collector-emitter voltage, was validated up to 325 GHz.

  4. Inhibition of ERK1/2 Pathway Suppresses Adiponectin Secretion via Accelerating Protein Degradation by Ubiquitin-Proteasome System: Relevance to Obesity-related Adiponectin Decline

    PubMed Central

    Gu, Dongfang; Wang, Zhigang; Dou, Xiaobing; Zhang, Ximei; Li, Songtao; Vu, Lyndsey; Yao, Tong; Song, Zhenyuan

    2013-01-01

    Objective Predominantly secreted by adipose tissue, adiponectin possesses insulin-sensitizing, anti-atherogenic, anti-inflammatory, and anti-angiogenic properties. Paradoxically, obesity is associated with declined plasma adiponectin levels; however, the underlying mechanisms remain elusive. In this study, we investigated the mechanistic involvement of MEK/ERK1/2 pathway in obesity-related adiponectin decrease. Materials/Methods C57 BL/6 mice exposed to a high-fat diet (HFD) were employed as animal obesity model. Both fully-differentiated 3T3-L1 and mouse primary adipocytes were used in the in vitro experiments. Results Obesity and plasma adiponectin decline induced by prolonged HFD exposure was associated with suppressed ERK1/2 activation in adipose tissue. In adipocytes, specific inhibition of MEK/ERK1/2 pathway decreased intracellular and secretory adiponectin levels, whereas adiponectin gene expression was increased, suggesting that MEK/ERK1/2 inhibition may promote adiponectin protein degradation. Cycloheximide (CHX)-chase assay revealed that MEK/ERK1/2 inhibition accelerated adiponectin protein degradation, which was prevented by MG132, a potent proteasome inhibitor. Immunoprecipitation assay showed that intracellular MEK/ERK1/2 activity was negatively associated with ubiqutinated adiponectin protein levels. Consistently, long-term HFD feeing in mice increased ubiquitinated adiponectin levels in the epididymal fat pads. Conclusions Adipose tissue MEK/ERK1/2 activity can differentially regulates adiponectin gene expression and protein abundance and its suppression in obesity may play a mechanistic role in obesity-related plasma adiponectin decline. PMID:23490586

  5. The Implications of ACTS Technology on the Requirements of Rain Attenuation Modeling for Communication System Specification and Analysis at 30/20 GHz and Beyond

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    1996-01-01

    The advent of the use of the Ka-Band for space communications, coupled with the introduction of digital modulation techniques as well as multiple-beam methodology for satellites, has deemed it necessary to reassess the plethora of rain attenuation prediction models in use. The Advanced Communication Technology Satellite (ACTS) Project, undertaken by the National Aeronautics and Space Administration in 1983, offered such challenges to rain attenuation prediction modeling. Up to 1983, no such single modeling formalism existed that could fill such requirements. Not even the work done by the NASA Propagation Experimenters (NAPEX) Group had envisioned such requirements, so no dynamic Ka-Band data existed from which one could draw conclusions. In this paper, the basic rudiments of what has become to be known as the 'ACTS Rain Attenuation Prediction Model' will be presented. The concept of rain fade mitigation control availability will be introduced. A new evaluation is then presented for the performance of satellite communication systems, in particular, those to be operating within the Ka-Band and above, that will necessarily employ some type of dynamic rain fade mitigation procedure.

  6. Submillimeter Spectroscopy with a 500-1000 GHz SIS Receiver

    NASA Technical Reports Server (NTRS)

    Zmuidzinas, J.

    1997-01-01

    Sub-millimeter Spectroscopy with a 500-1000 GHz SIS Receiver, which extended over the period October 1, 1991 through January 31, 1997. The purpose of the grant was to fund the development and construction of a sensitive heterodyne receiver system for the submillimeter band (500-1000 GHz), using our newly-developed sensitive superconducting (SIS) detectors, and to carry out astronomical observations with this system aboard the NASA Kuiper Air- borne Observatory (a Lockheed C-141 aircraft carrying a 91 cm telescope). A secondary purpose of the grant was to stimulate the continued development of sensitive submillimeter detectors, in order to prepare for the next-generation airborne observatory, SOFIA, as well as future space missions (such as the ESA/NASA FIRST mission).

  7. Future mobile satellite communication concepts at 20/30 GHz

    NASA Astrophysics Data System (ADS)

    Barton, S. K.; Norbury, J. R.

    The outline of a design of a system using ultra small earth stations (picoterminals) for data traffic at 20/30 GHz is discussed. The picoterminals would be battery powered, have an RF transmitter power of 0.5 W, use a 10 cm square patch antenna, and have a receiver G/T of about -8 dB/K. Spread spectrum modulation would be required (due to interference consideration) to allow a telex type data link (less than 200 bit/s data rate) from the picoterminal to the hub station of the network and about 40 kbit/s on the outbound patch. An Olympus type transponder at 20/30 GHz could maintain several thousand simultaneous picoterminal circuits. The possibility of demonstrating a picoterminal network with voice traffic using Olympus is discussed together with fully mobile systems based on this concept.

  8. Future mobile satellite communication concepts at 20/30 GHz

    NASA Technical Reports Server (NTRS)

    Barton, S. K.; Norbury, J. R.

    1990-01-01

    The outline of a design of a system using ultra small earth stations (picoterminals) for data traffic at 20/30 GHz is discussed. The picoterminals would be battery powered, have an RF transmitter power of 0.5 W, use a 10 cm square patch antenna, and have a receiver G/T of about -8 dB/K. Spread spectrum modulation would be required (due to interference consideration) to allow a telex type data link (less than 200 bit/s data rate) from the picoterminal to the hub station of the network and about 40 kbit/s on the outbound patch. An Olympus type transponder at 20/30 GHz could maintain several thousand simultaneous picoterminal circuits. The possibility of demonstrating a picoterminal network with voice traffic using Olympus is discussed together with fully mobile systems based on this concept.

  9. MMIC DHBT Common-Base Amplifier for 172 GHz

    NASA Technical Reports Server (NTRS)

    Paidi, Vamsi; Griffith, Zack; Wei, Yun; Dahlstrom, Mttias; Urteaga, Miguel; Rodwell, Mark; Samoska, Lorene; Fung, King Man; Schlecht, Erich

    2006-01-01

    Figure 1 shows a single-stage monolithic microwave integrated circuit (MMIC) power amplifier in which the gain element is a double-heterojunction bipolar transistor (DHBT) connected in common-base configuration. This amplifier, which has been demonstrated to function well at a frequency of 172 GHz, is part of a continuing effort to develop compact, efficient amplifiers for scientific instrumentation, wide-band communication systems, and radar systems that will operate at frequencies up to and beyond 180 GHz. The transistor is fabricated from a layered structure formed by molecular beam epitaxy in the InP/InGaAs material system. A highly doped InGaAs base layer and a collector layer are fabricated from the layered structure in a triple mesa process. The transistor includes two separate emitter fingers, each having dimensions of 0.8 by 12 m. The common-base configuration was chosen for its high maximum stable gain in the frequency band of interest. The input-matching network is designed for high bandwidth. The output of the transistor is matched to a load line for maximum saturated output power under large-signal conditions, rather than being matched for maximum gain under small-signal conditions. In a test at a frequency of 172 GHz, the amplifier was found to generate an output power of 7.5 mW, with approximately 5 dB of large-signal gain (see Figure 2). Moreover, the amplifier exhibited a peak small-signal gain of 7 dB at a frequency of 176 GHz. This performance of this MMIC single-stage amplifier containing only a single transistor represents a significant advance in the state of the art, in that it rivals the 170-GHz performance of a prior MMIC three-stage, four-transistor amplifier. [The prior amplifier was reported in "MMIC HEMT Power Amplifier for 140 to 170 GHz" (NPO-30127), NASA Tech Briefs, Vol. 27, No. 11 (November 2003), page 49.] This amplifier is the first heterojunction- bipolar-transistor (HBT) amplifier built for medium power operation in this

  10. Microwave ablation at 10.0 GHz achieves comparable ablation zones to 1.9 GHz in ex vivo bovine liver.

    PubMed

    Luyen, Hung; Gao, Fuqiang; Hagness, Susan C; Behdad, Nader

    2014-06-01

    We demonstrate the feasibility of using high-frequency microwaves for tissue ablation by comparing the performance of a 10 GHz microwave ablation system with that of a 1.9 GHz system. Two sets of floating sleeve dipole antennas operating at these frequencies were designed and fabricated for use in ex vivo experiments with bovine livers. Combined electromagnetic and transient thermal simulations were conducted to analyze the performance of these antennas. Subsequently, a total of 16 ablation experiments (eight at 1.9 GHz and eight at 10.0 GHz) were conducted at a power level of 42 W for either 5 or 10 min. In all cases, the 1.9 and 10 GHz experiments resulted in comparable ablation zone dimensions. Temperature monitoring probes revealed faster heating rates in the immediate vicinity of the 10.0 GHz antenna compared to the 1.9 GHz antenna, along with a slightly delayed onset of heating farther from the 10 GHz antenna, suggesting that heat conduction plays a greater role at higher microwave frequencies in achieving a comparably sized ablation zone. The results obtained from these experiments agree very well with the combined electromagnetic/thermal simulation results. These simulations and experiments show that using lower frequency microwaves does not offer any significant advantages, in terms of the achievable ablation zones, over using higher frequency microwaves. Indeed, it is demonstrated that high-frequency microwave antennas may be used to create reasonably large ablation zones. Higher frequencies offer the advantage of smaller antenna size, which is expected to lead to less invasive interstitial devices and may possibly lead to the development of more compact multielement arrays with heating properties not available from single-element antennas.

  11. Effect of benzoic acid on the removal of 1,2-dichloroethane by a siderite-catalyzed hydrogen peroxide and persulfate system.

    PubMed

    Li, Shengpin; Li, Mengjiao; Luo, Ximing; Huang, Guoxin; Liu, Fei; Chen, Honghan

    2016-01-01

    Benzoic acid can affect the iron-oxide mineral dissolution and react with hydroxyl radical. This study investigated its effect on 1,2-dichloroethane removal process by siderite-catalyzed hydrogen peroxide and persulfate. The variation of benzoic acid concentrations can affect pH value and soluble iron concentrations; when benzoic acid varied from 0 to 0.5 mmol/L, pH increased while Fe(2+) and Fe(3+) concentrations decreased, resulting in 1,2-dichloroethane removal efficiency which decreased from 91.2 to 5.0%. However, when benzoic acid varied from 0.5 to 10 mmol/L, pH decreased while Fe(2+) and Fe(3+) concentrations increased, resulting in 1,2-dichloroethane removal efficiency which increased from 5.0 to 83.4%.

  12. Design of a 60 GHz beam waveguide antenna positioner

    NASA Technical Reports Server (NTRS)

    Emerick, Kenneth S.

    1989-01-01

    A development model antenna positioner mechanism with an integral 60 GHz radio frequency beam waveguide is discussed. The system features a 2-ft diameter carbon-fiber reinforced epoxy antenna reflector and support structure, and a 2-degree-of-freedom elevation over azimuth mechanism providing hemispherical field of view. Emphasis is placed on the constraints imposed on the mechanism by the radio frequency subsystems and how they impacted the mechanical configuration.

  13. 160 Gbit/s photonics wireless transmission in the 300-500 GHz band

    NASA Astrophysics Data System (ADS)

    Yu, X.; Jia, S.; Hu, H.; Galili, M.; Morioka, T.; Jepsen, P. U.; Oxenløwe, L. K.

    2016-11-01

    To accommodate the ever increasing wireless traffic in the access networks, considerable efforts have been recently invested in developing photonics-assisted wireless communication systems with very high data rates. Superior to photonic millimeter-wave systems, terahertz (THz) band (300 GHz-10 THz) provides a much larger bandwidth and thus promises an extremely high capacity. However, the capacity potential of THz wireless systems has by no means been achieved yet. Here, we successfully demonstrate 160 Gbit/s wireless transmission by using a single THz emitter and modulating 25 GHz spaced 8 channels (20 Gbps per channel) in the 300-500 GHz band, which is the highest bitrate in the frequency band above 300 GHz, to the best of our knowledge.

  14. Initial Testing of a 140 GHz 1 MW Gyrotron

    NASA Astrophysics Data System (ADS)

    Cauffman, Stephen; Felch, Kevin; Blank, Monica; Borchard, Philipp; Cahalan, Pat; Chu, Sam; Jory, Howard

    2001-10-01

    CPI has completed the fabrication of a 140 GHz 1 MW CW gyrotron to be used on the W7-X stellarator at IPP Greifswald. Testing of the initial build of this gyrotron had just begun when this abstract was prepared, and was expected to finish in September, at which time a planned rebuild of the device was scheduled to begin. This poster will summarize the gyrotron design, present results of initial testing, and outline any design changes planned as a consequence of these results. This gyrotron's design employs a number of advanced features, including a diode electron gun for simplified operation, a single-stage depressed collector to enhance overall efficiency, a CVD diamond output window, an internal mode converter that converts the excited TE28,7 cavity mode to a Gaussian output beam, and a high-voltage layout that locates all external high voltage below the superconducting magnet system without requiring an oil tank for insulation. Similar features are being used for an 84 GHz 500 kW system being built for the KSTAR tokamak program and for a 110 GHz 1.5 MW system being designed in collaboration with MIT, UMd, UW, GA, and Calabazas Creek Research with funding provided by DOE.

  15. Calibration of a 35-GHz Airborne Cloud Radar: Lessons Learned and Intercomparison with a 94-GHz Airborne Cloud Radar

    NASA Astrophysics Data System (ADS)

    Ewald, Florian; Gross, Silke; Hagen, Martin; Hirsch, Lutz; Delanoë, Julien

    2017-04-01

    Clouds play an important role in the climate system since they have a profound influence on Earth's radiation budget and the water cycle. Uncertainties associated with their spatial characteristics as well as their microphysics still introduce large uncertainties in climate change predictions. In recent years, our understanding of the inner workings of clouds has been greatly advanced by the deployment of cloud profiling microwave radars from ground as well as from space like CloudSat or the upcoming EarthCARE satellite mission. In order to validate and assess the limitations of these spaceborne missions, a well-calibrated, airborne cloud radar with known sensitivity to clouds is indispensable. Within this context, the German research aircraft HALO was equipped with the high-power (30kW peak power) cloud radar operating at 35 GHz and a high spectral resolution lidar (HSRL) system at 532 nm. During a number of flight experiments over Europe and over the tropical and extra-tropical North-Atlantic, several radar calibration efforts have been made using the ocean surface backscatter. Moreover, CloudSat underflights have been conducted to compare the radar reflectivity and measurement sensitivity between the air- and spaceborne instruments. Additionally, the influence of different radar wavelengths was explored with joint flights of HALO and the French Falcon 20 aircraft, which was equipped with the RASTA cloud radar at 94 GHz and a HSRL at 355 nm. In this presentation, we will give an overview of lessons learned from different calibration strategies using the ocean surface backscatter. Additional measurements of signal linearity and signal saturation will complement this characterization. Furthermore, we will focus on the coordinated airborne measurements regarding the different sensitivity for clouds at 35 GHz and 94 GHz. By using the highly sensitive lidar signals, we show if the high-power cloud radar at 35 GHz can be used to validate spaceborne and airborne

  16. ASUR -- An airborne SIS receiver for atmospheric measurements of trace gases at 625--760 GHz

    SciTech Connect

    Mees, J.; Stadt, H. van de; Panhuyzen, R.A.; Crewell, S.; Nett, H.; Lange, G. de; Kuipers, J.J.

    1995-11-01

    A heterodyne receiver making use of a SIS waveguide mixer with integrated horn and single backshort tuner has been built. It has been used for a series of airborne measurements of atmospheric trace gases, such as HCl and ClO, above northern Europe during the winter of 1993 and 1994. The receiver is suitable for measurements in the range of 625--760 GHz and shows stable operation in the airplane together with high sensitivity. Best achieved noise temperature are T{sub DSB} = 310 K at 708 GHz in the laboratory and T{sub SSB} = 1,500 K at 625 GHz for the complete system in the airplane.

  17. 77 GHz radar for first responders

    NASA Astrophysics Data System (ADS)

    Kosowsky, L. H.; Aronoff, A. D.; Ferraro, R.; Alland, S.; Fleischman, E.

    2017-02-01

    First responders have the dangerous task of responding to emergency situations in firefighting scenarios involving homes and offices. The importance of this radar is its ability to see through walls and into adjacent areas to provide the first responder with information to assess the status of a building fire, its occupants, and to supplement his thermal camera which is obstructed by the wall. For the firefighter looking into an adjacent room containing unknown objects including humans, the challenge is to recognize what is in that room, the configuration of the room, and potential escape routes. We have just concluded a series of experiments to illustrate the performance of 77GHz radar in buildings. The experiments utilized the Delphi Automotive radar as the mm wave sensor and included display software developed by L. H. Kosowsky and Associates. The system has demonstrated the capability of seeing through walls consisting of sheetrock separated by two by four pieces of wood. It has demonstrated the ability to see into the adjacent room and to display the existence of persons and furniture Based on published data, the radar will perform well in a smoke, haze, and/or fog environment.

  18. 47 CFR 15.251 - Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz, and 3.358-3.6 GHz.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz, and 3.358-3.6 GHz. 15.251 Section 15.251 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission...

  19. 47 CFR 15.251 - Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz, and 3.358-3.6 GHz.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz, and 3.358-3.6 GHz. 15.251 Section 15.251 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission...

  20. 47 CFR 15.251 - Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz, and 3.358-3.6 GHz.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz, and 3.358-3.6 GHz. 15.251 Section 15.251 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission...

  1. 47 CFR 15.251 - Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz, and 3.358-3.6 GHz.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz, and 3.358-3.6 GHz. 15.251 Section 15.251 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission...

  2. 47 CFR 15.251 - Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz, and 3.358-3.6 GHz.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz, and 3.358-3.6 GHz. 15.251 Section 15.251 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission...

  3. Extended depth of field imaging at 94 GHz

    NASA Astrophysics Data System (ADS)

    Mait, Joseph N.; Wikner, David A.; Mirotznik, Mark S.; van der Gracht, Joseph; Behrmann, Gregory P.; Good, Brandon L.; Mathews, Scott A.

    2008-04-01

    We describe a computational imaging technique to extend the depth-of field of a 94-GHz imaging system. The technique uses a cubic phase element in the pupil plane of the system to render system operation relatively insensitive to object distance. However, the cubic phase element also introduces aberrations but, since these are fixed and known, we remove them using post-detection signal processing. We present experimental results that validate system performance and indicate a greater than four-fold increase in depth-of-field from 17" to greater than 68".

  4. First Results of the Superconducting ECR Ion Source Venus with 28 GHz

    SciTech Connect

    Leitner, D.; Lyneis, C.M.; Abbott, S.R.; Dwinell, R.D.; Collins, D.; Leitner, M.

    2005-03-15

    VENUS (Versatile ECR ion source for NUclear Science) is a next generation superconducting ECR ion source, designed to produce high current, high charge state ions for the 88-Inch Cyclotron at the Lawrence Berkeley National Laboratory. VENUS also serves as the prototype ion source for the RIA (Rare Isotope Accelerator) front end. The magnetic confinement configuration consists of three superconducting axial coils and six superconducting radial coils in a sextupole configuration. The nominal design fields of the axial magnets are 4T at injection and 3T at extraction; the nominal radial design field strength at the plasma chamber wall is 2T, making VENUS the world most powerful ECR plasma confinement structure. From the beginning, VENUS has been designed for optimum operation at 28 GHz with high power (10 kW).In 2003 the VENUS ECR ion source was commissioned at 18 GHz, while preparations for 28 GHz operation were being conducted. During this commissioning phase with 18 GHz, tests with various gases and metals have been performed with up to 2000 W RF power. At the initial commissioning tests at 18 GHz, 1100 e{mu}A of O6+, 160 e{mu}A of Xe20+, 160 e{mu}A of Bi25+ and 100 e{mu}A of Bi30+ and 11 e{mu}A of Bi41+ were produced.In May 2004 the 28 GHz microwave power has been coupled into the VENUS ECR ion source. At initial operation more than 320 e{mu}A of Xe20+ (twice the amount extracted at 18 GHz), 240 e{mu}A of Bi24+ and Bi25+, and 245 e{mu}A of Bi29+ were extracted. The paper briefly describes the design of the VENUS source, the 28 GHz microwave system and its beam analyzing system. First results at 28 GHz including emittance measurements are presented.

  5. A Deterministic and Random Propagation Study with the Design of an Open Path 320 GHz to 340 GHz Transmissometer

    NASA Astrophysics Data System (ADS)

    Scally, Lawrence J.

    This program was implemented by Lawrence J. Scally for a Ph.D. under the EECE department at the University of Colorado at Boulder with most funding provided by the U.S. Army. Professor Gasiewski is the advisor and guider for the entire program; he has a strong history decades ago in this type of program. This program is developing a more advanced than previous years transmissometer, called Terahertz Atmospheric and Ionospheric Propagation, Absorption and Scattering System (TAIPAS), on an open path between the University of Colorado EE building roof and the mesa on owned by National Institute of Standards and Technology (NIST); NIST has invested money, location and support for the program. Besides designing and building the transmissometer, that has never be accomplished at this level, the system also analyzes the atmospheric propagation of frequencies by scanning between 320 GHz and 340 GHz, which includes the peak absorption frequency at 325.1529 GHz due to water absorption. The processing and characterization of the deterministic and random propagation characteristics of the atmosphere in the real world was significantly started; this will be executed with varies aerosols for decades on the permanently mounted system that is accessible 24/7 via a network over the CU Virtual Private Network (VPN).

  6. Snow backscatter in the 1-8 GHz region

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T.

    1976-01-01

    The 1-8 GHz microwave active spectrometer system was used to measure the backscatter response of snow covered ground. The scattering coefficient was measured for all linear polarization combinations at angles of incidence between nadir and 70 deg. Ground truth data consisted of soil moisture, soil temperature profile, snow depth, snow temperature profile, and snow water equivalent. The radar sensitivity to snow water equivalent increased in magnitude with increasing frequency and was almost angle independent for angles of incidence higher than 30 deg, particularly at the higher frequencies. In the 50 deg to 70 deg angular range and in the 6 to 8 GHz frequency range, the sensitivity was typically between -0.4 dB/.1 g/sq cm and -0.5 dB/,1 g/sq cm, and the associated linear correlation coefficient had a magnitude of about 0.8.

  7. Millimeter wave absorption in the nonhuman primate eye at 35 GHz and 94 GHz.

    PubMed

    Chalfin, Steven; D'Andrea, John A; Comeau, Paul D; Belt, Michael E; Hatcher, Donald J

    2002-07-01

    The purpose of this study was to evaluate anterior segment bioeffects of pulsed 35 GHz and 94 GHz microwave exposure in the nonhuman primate eye. Five juvenile rhesus monkeys (Macaca mulatta) underwent baseline anterior segment ocular assessment consisting of slit lamp examination, corneal topography, specular microscopy, and pachymetry. These studies were repeated after exposure of one eye to pulsed 35 GHz or 94 GHz microwaves at varied fluences, with the other eye serving as a control. The mean fluence required to produce a threshold corneal lesion (faint epithelial edema and fluorescein staining) was 7.5 J cm(-2) at 35 GHz and 5 J cm(-2) at 94 GHz. Transient changes in corneal topography and pachymetry were noted at these fluences. Endothelial cell counts remained unchanged. Threshold corneal injury from 35 GHz and 94 GHz microwave exposure is produced at fluences below those previously reported for CO2 laser radiation. These data may help elucidate the mechanism of thermal injury to the cornea, and resolve discrepancies between IEEE C95.1 (1999), NCRP (1986), and ICNIRP (1998) safety standards for exposure to non-ionizing radiation at millimeter wavelengths.

  8. Architecture for a 1-GHz Digital RADAR

    NASA Technical Reports Server (NTRS)

    Mallik, Udayan

    2011-01-01

    An architecture for a Direct RF-digitization Type Digital Mode RADAR was developed at GSFC in 2008. Two variations of a basic architecture were developed for use on RADAR imaging missions using aircraft and spacecraft. Both systems can operate with a pulse repetition rate up to 10 MHz with 8 received RF samples per pulse repetition interval, or at up to 19 kHz with 4K received RF samples per pulse repetition interval. The first design describes a computer architecture for a Continuous Mode RADAR transceiver with a real-time signal processing and display architecture. The architecture can operate at a high pulse repetition rate without interruption for an infinite amount of time. The second design describes a smaller and less costly burst mode RADAR that can transceive high pulse repetition rate RF signals without interruption for up to 37 seconds. The burst-mode RADAR was designed to operate on an off-line signal processing paradigm. The temporal distribution of RF samples acquired and reported to the RADAR processor remains uniform and free of distortion in both proposed architectures. The majority of the RADAR's electronics is implemented in digital CMOS (complementary metal oxide semiconductor), and analog circuits are restricted to signal amplification operations and analog to digital conversion. An implementation of the proposed systems will create a 1-GHz, Direct RF-digitization Type, L-Band Digital RADAR--the highest band achievable for Nyquist Rate, Direct RF-digitization Systems that do not implement an electronic IF downsample stage (after the receiver signal amplification stage), using commercially available off-the-shelf integrated circuits.

  9. Studying Star Formation in the Central Molecular Zone using 22 GHz Water and 6.7 GHz Methanol Masers

    NASA Astrophysics Data System (ADS)

    Rickert, Matthew; Yusef-Zadeh, Farhad; Ott, Juergen; Meier, David S.; SWAG

    2016-01-01

    The inner 400 pc of our Galaxy, or the so-called the central molecular zone (CMZ), has a unique environment with a large mass of dense, warm molecular gas. One of the premier questions is how star formation (SF) differs in this unique environment from elsewhere in the Galaxy. We intend to address this issue by identifying improved numbers and locations of early sites of SF. We have conducted high resolution surveys of the CMZ, looking for early SF indicators such as 22 GHz water and 6.7 GHz methanol masers. We present the initial water maser results from the SWAG survey and methanol results from the first full VLA survey of 6.7 GHz methanol masers in the CMZ. These surveys span beyond the inner 1.2ο x 0.5ο of the Galaxy, including Sgr B through Sgr C. The improved spatial and spectral resolutions (~26" and 2 km s-1) and sensitivity (RMS ~10 mJy beam-1) of our ATCA observations have allowed us to identify over 140 water maser candidates in the SWAG survey. This is a factor of 3 more than detected from prior surveys of the CMZ. The preliminary distribution of these candidates appears to be uniform along Galactic longitude. Should this distribution persist for water masers associated with star formation (as opposed to those produced by evolved stars), then this result would imply a more uniform distribution of recent SF activity in the CMZ. Prior works have shown that 2/3 of the molecular gas mass is located at positive Galactic longitudes, and young stellar objects (YSOs) identified by IR SEDs are located predominantly at negative Galactic longitudes. A combination of these results can provide insight on the evolution of SF within the CMZ. We are currently comparing the water maser positions to other catalogs (ex. OH/IR stars) in order to distinguish between the mechanisms producing these masers. We are also currently working on determining the distribution of 6.7 GHz methanol masers. These masers do not contain the same ambiguity as water masers as to their source

  10. Lightning and 85-GHz MCSs in the Global Tropics

    NASA Technical Reports Server (NTRS)

    Toracinta, E. Richard; Zipser, E. J.

    1999-01-01

    Numerous observations of tropical convection show that tropical continental mesoscale convective systems (MCSs) are much more prolific lightning producers than their oceanic counterparts. Satellite-based climatologies using 85-GHz passive microwave ice-scattering signatures from the Special Sensor Microwave/Imager (SSM/I) indicate that MCSs of various size and intensity are found throughout the global tropics. In contrast, global lightning distributions show a strong land bias with an order of magnitude difference between land and ocean lightning. This is somewhat puzzling, since 85-GHz ice-scattering and the charge separation processes that lead to lightning are both thought to depend upon the existence of large graupel particles. The fact that low 85-GHz brightness temperatures are observed in tropical oceanic MCSs containing virtually no lightning leads to the postulate that tropical oceanic and tropical continental MCSs have fundamentally different hydrometeor profiles through the mixed phase region of the cloud (0 C <= T <= 20 C). Until recently, validation of this postulate has not been practicable on a global scale. Recent deployment of the Tropical Rainfall Measuring Mission (TRMM) satellite presents a unique opportunity for MCS studies. The multi-sensor instrument ensemble aboard TRMM, including a multi-channel microwave radiometer, the Lightning Imaging Sensor (LIS), and the first space-borne radar, facilitates high-resolution case studies of MCS structure throughout the global tropics. An important precursor, however, is to better understand the distribution of MCSs and lightning in the tropics. With that objective in mind, this research undertakes a systematic comparison of 85-GHz-defined MCSs and lightning over the global tropics for a full year, as an initial step toward quantifying differences between land and ocean convective systems.

  11. Lightning and 85-GHz MCSs in the Global Tropics

    NASA Technical Reports Server (NTRS)

    Toracinta, E. Richard; Zipser, E. J.

    1999-01-01

    Numerous observations of tropical convection show that tropical continental mesoscale convective systems (MCSs) are much more prolific lightning producers than their oceanic counterparts. Satellite-based climatologies using 85-GHz passive microwave ice-scattering signatures from the Special Sensor Microwave/Imager (SSM/I) indicate that MCSs of various size and intensity are found throughout the global tropics. In contrast, global lightning distributions show a strong land bias with an order of magnitude difference between land and ocean lightning. This is somewhat puzzling, since 85-GHz ice-scattering and the charge separation processes that lead to lightning are both thought to depend upon the existence of large graupel particles. The fact that low 85-GHz brightness temperatures are observed in tropical oceanic MCSs containing virtually no lightning leads to the postulate that tropical oceanic and tropical continental MCSs have fundamentally different hydrometeor profiles through the mixed phase region of the cloud (0 C <= T <= 20 C). Until recently, validation of this postulate has not been practicable on a global scale. Recent deployment of the Tropical Rainfall Measuring Mission (TRMM) satellite presents a unique opportunity for MCS studies. The multi-sensor instrument ensemble aboard TRMM, including a multi-channel microwave radiometer, the Lightning Imaging Sensor (LIS), and the first space-borne radar, facilitates high-resolution case studies of MCS structure throughout the global tropics. An important precursor, however, is to better understand the distribution of MCSs and lightning in the tropics. With that objective in mind, this research undertakes a systematic comparison of 85-GHz-defined MCSs and lightning over the global tropics for a full year, as an initial step toward quantifying differences between land and ocean convective systems.

  12. Supplement Analysis for the Transmission System Vegetation Management Program FEIS (DOE/EIS-0285/SA-146-Custer-Ingledow No. 1 & 2)

    SciTech Connect

    Shurtliff, Aaron

    2003-04-29

    Vegetation Management for portion of the Custer-Ingledow No.1&2 500 kV transmission line located from tower structure 1/4 to 9/6. BPA proposes to clear unwanted vegetation in the rights-of-ways and around tower structures that may impede the operation and maintenance of the subject transmission line. Also, access road clearing will be conducted.

  13. 47 CFR 25.143 - Licensing provisions for the 1.6/2.4 GHz Mobile-Satellite Service and 2 GHz Mobile-Satellite...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... information specified in § 25.114. Non-U.S. licensed systems shall comply with the provisions of § 25.137. (2... within the described geographic area; (iii) That a system proposed to operate using non-geostationary... service within U.S. territorial geographic areas, and the amount of unused system capacity. 2 GHz Mobile...

  14. The 4-8 GHz Microwave Active and Passive Spectrometer (MAPS). Volume 1: Radar section

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T.

    1973-01-01

    The performance characteristics of the radar section of the prototype 4-8 GHz Microwave Active and Passive Spectrometer system are reported. Active and passive spectral responses were measured of natural, cultivated, and human-made surfaces over the 4-18 GHz region of frequencies for look angles between zero and 70 degrees and for all possible linear polarization combinations. Soil and plant samples were collected to measure their dielectric properties and moisture content. The FORTRAN program for area calculation is provided.

  15. 140-GHz pulsed Fourier transform microwave spectrometer

    NASA Astrophysics Data System (ADS)

    Kolbe, W. F.; Leskovar, B.

    1985-01-01

    A pulsed microwave spectrometer operating in the vicinity of 140 GHz for the detection of rotational transitions in gaseous molecules is described. The spectrometer incorporates a tunable Fabry-Perot cavity and a subharmonically pumped superheterodyne receiver for the detection of the molecular emission signals. A 70-GHz source supplying a high-efficiency frequency doubler which is pulse modulated at 30 MHz produces sidebands of sufficient power at 140 GHz to excite the molecules. The cavity is tuned to one of the modulation sidebands. The operation of the spectrometer is illustrated by the detection of emission signals from the 6(2, 4)-6(1, 5) transition of SO2 gas. The generation of the electric dipole analog of nuclear-magnetic-resonance (NMR) ``spin-echo'' signals by a π/2-π pulse sequence is also described.

  16. Low noise amplifiers above 18 GHz

    NASA Astrophysics Data System (ADS)

    Kennan, W.; Chye, P.

    Noise reduction in ground stations operating above 18 GHz are explored in terms of current limitations in device, measurement and circuit technology and progress on a low noise amplifier. GaAs FETs have, as of 1982, reached a level of 1.55 dB noise and 12.3 dB gain. The devices include a 75 micron gate width and sub-quarter micron gate length. The noise figures are thus far determined in the 20-22 GHz range. A balanced microstrip circuit 0.65 x 0.51 cm in size featuring Lange couplers, input and output matching circuits, quarter wavelength bias chokes and TaN resistor bias networks has been developed for VSWR and cascading stages applications. The amplifier, in a two-stage configuration, has furnished a bandwidth of 12-22 GHz.

  17. A 12 GHz broadband latching circulator

    NASA Astrophysics Data System (ADS)

    Katoh, Y.; Konishi, H.; Sakamoto, K.

    The two kinds of latching circulators, external return path and internal return path, are defined, noting the advantages (faster switching speed, lower switching energy, less complicated fabrication) offered by the internal configuration. It is noted, however, that this kind of circulator is difficult to make broadband because the return paths do not seem to act as part of the ferrite junction. The development of a 12-GHz broadband, internal return path circulator with impedance matching transformer and in-phase adjustment screws designed using eigenvalue measurement is described. In describing the operating characteristics, it is noted that more than 25 dB isolation over 11 GHz to 13.5 GHz and 0.25 dB insertion loss is obtained.

  18. Characterization of Power MESFETs at 21 GHz.

    DTIC Science & Technology

    1981-09-15

    constructed for use between 12 and 24 GHz based on a microwave- diplexer filter. The bias-tee is constructed using air and teflon- loaded coaxial transmission...FREQUENCY 21 GHz GAIN (dB) VDe 6.5 V 8 I = 139 mnA AT RF MAX 7 28- D 6 z171 mnA no RF 5 4 -186 mnA AT 22.9 24 -dBmn OUTImI 2020 ~16- 14 12 12 88 4 4

  19. 17 GHz High Gradient Accelerator Research

    SciTech Connect

    Temkin, Richard J.; Shapiro, Michael A.

    2013-07-10

    This is a report on the MIT High Gradient Accelerator Research program which has included: Operation of the 17 GHz, 25 MeV MIT/Haimson Research Corp. electron accelerator at MIT, the highest frequency, stand-alone accelerator in the world; collaboration with members of the US High Gradient Collaboration, including the design and test of novel structures at SLAC at 11.4 GHz; the design, construction and testing of photonic bandgap structures, including metallic and dielectric structures; the investigation of the wakefields in novel structures; and the training of the next generation of graduate students and postdoctoral associates in accelerator physics.

  20. The 60 GHz solid state power amplifier

    NASA Technical Reports Server (NTRS)

    Mcclymonds, J.

    1991-01-01

    A new amplifier architecture was developed during this contract that is superior to any other solid state approach. The amplifier produced 6 watts with 4 percent efficiency over a 2 GHz band at 61.5 GHz. The unit was 7 x 9 x 3 inches in size, 5.5 pounds in weight, and the conduction cooling through the baseplate is suitable for use in space. The amplifier used high efficiency GaAs IMPATT diodes which were mounted in 1-diode circuits, called modules. Eighteen modules were used in the design, and power combining was accomplished with a proprietary passive component called a combiner plate.

  1. 95 GHz gyrotron with ferroelectric cathode.

    PubMed

    Einat, M; Pilossof, M; Ben-Moshe, R; Hirshbein, H; Borodin, D

    2012-11-02

    Ferroelectric cathodes were reported as a feasible electron source for microwave tubes. However, due to the surface plasma emission characterizing this cathode, operation of millimeter wave tubes based on it remains questionable. Nevertheless, the interest in compact high power sources of millimeter waves and specifically 95 GHz is continually growing. In this experiment, a ferroelectric cathode is used as an electron source for a gyrotron with the output frequency extended up to 95 GHz. Power above a 5 kW peak and ~0.5 μs pulses are reported; a duty cycle of 10% is estimated to be achievable.

  2. Generic fixed point model for pseudo-spin-1/2 quantum dots in nonequilibrium: Spin-valve systems with compensating spin polarizations

    NASA Astrophysics Data System (ADS)

    Göttel, Stefan; Reininghaus, Frank; Schoeller, Herbert

    2015-07-01

    We study a pseudo-spin-1/2 quantum dot in the cotunneling regime close to the particle-hole symmetric point. For a generic tunneling matrix we find a fixed point with interesting nonequilibrium properties, characterized by effective reservoirs with compensating spin orientation vectors weighted by the polarizations and the tunneling rates. At large bias voltage we study the magnetic field dependence of the dot magnetization and the current. The fixed point can be clearly identified by analyzing the magnetization of the dot. We characterize the universal properties for the case of two reservoirs and discuss deviations from the fixed point model in experimentally realistic situations.

  3. GHz low noise short wavelength infrared (SWIR) photoreceivers

    NASA Astrophysics Data System (ADS)

    Bai, Xiaogang; Yuan, Ping; McDonald, Paul; Boisvert, Joseph; Chang, James; Woo, Robyn; Labios, Eduardo; Sudharsanan, Rengarajan; Krainak, Michael; Yang, Guangning; Sun, Xiaoli; Lu, Wei; McIntosh, Dion; Zhou, Qiugui; Campbell, Joe

    2011-06-01

    Next generation LIDAR mapping systems require multiple channels of sensitive photoreceivers that operate in the wavelength region of 1.06 to 1.55 microns, with GHz bandwidth and sensitivity less than 300 fW/√Hz. Spectrolab has been developing high sensitivity photoreceivers using InAlAs impact ionization engineering (I2E) avalanche photodiodes (APDs) structures for this application. APD structures were grown using metal organic vapor epitaxy (MOVPE) and mesa devices were fabricated using these structures. We have achieved low excess noise at high gain in these APD devices; an impact ionization parameter, k, of about 0.15 has been achieved at gains >20 using InAlAs/InGaAlAs as a multiplier layer. Electrical characterization data of these devices show dark current less than 2 nA at a gain of 20 at room temperature; and capacitance of 0.4 pF for a typical 75 micron diameter APD. Photoreceivers were built by integrating I2E APDs with a low noise GHz transimpedance amplifier (TIA). The photoreceivers showed a bandwidth of 1 GHz and a noise equivalent power (NEP) of 150 fW/rt(Hz) at room temperature.

  4. 47 CFR 25.136 - Licensing provisions for user transceivers in the 1.6/2.4 GHz, 1.5/1.6 GHz, and 2 GHz Mobile...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Applications and Licenses Earth Stations § 25.136 Licensing provisions for user transceivers in the 1.6/2.4 GHz... specified in § 25.213, earth stations operating in the 1.6/2.4 GHz and 1.5/1.6 GHz Mobile Satellite Services... aircraft unless the earth station has a direct physical connection to the aircraft cabin or...

  5. Detection of 183 GHz H2O megamaser emission towards NGC 4945

    NASA Astrophysics Data System (ADS)

    Humphreys, E. M. L.; Vlemmings, W. H. T.; Impellizzeri, C. M. V.; Galametz, M.; Olberg, M.; Conway, J. E.; Belitsky, V.; De Breuck, C.

    2016-08-01

    Aims: The aim of this work is to search Seyfert 2 galaxy NGC 4945, a well-known 22 GHz water megamaser galaxy, for H2O (mega)maser emission at 183 GHz. Methods: We used APEX SEPIA Band 5 (an ALMA Band 5 receiver on the APEX telescope) to perform the observations. Results: We detected 183 GHz H2O maser emission towards NGC 4945 with a peak flux density of ~3 Jy near the galactic systemic velocity. The emission spans a velocity range of several hundred km s-1. We estimate an isotropic luminosity of >1000 L⊙, classifying the emission as a megamaser. A comparison of the 183 GHz spectrum with that observed at 22 GHz suggests that 183 GHz emission also arises from the active galactic nucleus (AGN) central engine. If the 183 GHz emission originates from the circumnuclear disk, then we estimate that a redshifted feature at 1084 km s-1 in the spectrum should arise from a distance of 0.022 pc from the supermassive black hole (1.6 × 105 Schwarzschild radii), i.e. closer than the water maser emission previously detected at 22 GHz. This is only the second time 183 GHz maser emission has been detected towards an AGN central engine (the other galaxy being NGC 3079). It is also the strongest extragalactic millimetre/submillimetre water maser detected to date. Conclusions: Strong millimetre 183 GHz H2O maser emission has now been shown to occur in an external galaxy. For NGC 4945, we believe that the maser emission arises, or is dominated by, emission from the AGN central engine. Emission at higher velocity, i.e. for a Keplerian disk closer to the black hole, has been detected at 183 GHz compared with that for the 22 GHz megamaser. This indicates that millimetre/submillimetre H2O masers can indeed be useful for tracing out more of AGN central engine structures and dynamics than previously probed. Future observations using ALMA Band 5 should unequivocally determine the origin of the emission in this and other galaxies.

  6. Development of 24GHz Rectenna for Receiving and Rectifying Modulated Waves

    NASA Astrophysics Data System (ADS)

    Shinohara, Naoki; Hatano, Ken

    2014-11-01

    In this paper, we show experimental results of RF-DC conversion with modulated 24GHz waves. We have already developed class-F MMIC rectenna with resonators for higher harmonics at no modulated 24GHz microwave for RF energy transfer. Dimensions of the MMIC rectifying circuit is 1 mm × 3 mm on GaAs. Maximum RF-DC conversion efficiency is measured 47.9% for a 210 mW microwave input of 24 GHz with a 120 Ω load. The class-F rectenna is based on a single shunt full-wave rectifier. For future application of a simultaneous energy and information transfer system or an energy harvesting from broadcasting waves, input microwave will be modulated. In this paper, we show an experimental result of RF-DC conversion of the class-F rectenna with 24GHz waves modulated by 16QAM as 1st modulation and OFDM as 2nd modulation.

  7. 3.5 Year Monitoring of 225 GHz Opacity at the Summit of Greenland

    NASA Astrophysics Data System (ADS)

    Matsushita, Satoki; Asada, Keiichi; Martin-Cocher, Pierre L.; Chen, Ming-Tang; Ho, Paul T. P.; Inoue, Makoto; Koch, Patrick M.; Paine, Scott N.; Turner, David D.

    2017-02-01

    We present the 3.5 years monitoring results of 225 GHz opacity at the summit of the Greenland ice sheet (Greenland Summit Camp) at an altitude of 3200 m using a tipping radiometer. We chose this site as our submillimeter telescope (Greenland Telescope) site, because conditions are expected to have low submillimeter opacity and because its location offers favorable baselines to existing submillimeter telescopes for global-scale Very Long Baseline Interferometry. The site shows a clear seasonal variation with the average opacity lower by a factor of two during winter. The 25%, 50%, and 75% quartiles of the 225 GHz opacity during the winter months of November through April are 0.046, 0.060, and 0.080, respectively. For the winter quartiles of 25% and 50%, the Greenland site is about 10%-30% worse than the Atacama Large Millimeter/submillimeter Array (ALMA) or the South Pole sites. Estimated atmospheric transmission spectra in winter season are similar to the ALMA site at lower frequencies (\\lt 450 GHz), which are transparent enough to perform astronomical observations almost all of the winter time with opacities \\lt 0.5, but 10%-25% higher opacities at higher frequencies (\\gt 450 GHz) than those at the ALMA site. This is due to the lower altitude of the Greenland site and the resulting higher line wing opacity from pressure-broadened saturated water lines in addition to higher dry air continuum absorption at higher frequencies. Nevertheless, half of the winter time at the Greenland Summit Camp can be used for astronomical observations at frequencies between 450 GHz and 1000 GHz with opacities \\lt 1.2, and 10% of the time show \\gt 10 % transmittance in the THz (1035 GHz, 1350 GHz, and 1500 GHz) windows. Summer season is good for observations at frequencies lower than 380 GHz. One major advantage of the Greenland Summit Camp site in winter is that there is no diurnal variation due to the polar night condition, and therefore the durations of low-opacity conditions

  8. The 20 GHz GaAs monolithic power amplifier module development

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The development of a 20 GHz GaAs FET monlithic power amplifier module for advanced communication applications is described. Four-way power combing of four 0.6 W amplifier modules is used as the baseline approach. For this purpose, a monolithic four-way traveling-wave power divider/combiner was developed. Over a 20 GHz bandwidth (10 to 30 GHz), an insertion loss of no more than 1.2 dB was measured for a pair of back-to-back connected divider/combiners. Isolation between output ports is better than 20 dB, and VSWRs are better than 21:1. A distributed amplifier with six 300 micron gate width FETs and gate and drain transmission line tapers has been designed, fabricated, and evaluated for use as an 0.6 W module. This amplifier has achieved state-of-the-art results of 0.5 W output power with at least 4 dB gain across the entire 2 to 21 GHz frequency range. An output power of 2 W was achieved at a measurement frequency of 18 GHz when four distributed amplifiers were power-combined using a pair of traveling-wave divider/combiners. Another approach is the direct common-source cascading of three power FET stages. An output power of up to 2W with 12 dB gain and 20% power-added efficiency has been achieved with this approach (at 17 GHz). The linear gain was 14 dB at 1 W output. The first two stages of the three-stage amplifier have achieved an output power of 1.6 W with 9 dB gain and 26% power-added efficiency at 16 GHz.

  9. A 670 GHz gyrotron with record power and efficiency

    NASA Astrophysics Data System (ADS)

    Glyavin, M. Yu.; Luchinin, A. G.; Nusinovich, G. S.; Rodgers, J.; Kashyn, D. G.; Romero-Talamas, C. A.; Pu, R.

    2012-10-01

    A 670 GHz gyrotron with record power and efficiency has been developed in joint experiments of the Institute of Applied Physics, Russian Academy of Sciences (Nizhny Novgord, Russia), and the University of Maryland (USA) teams. The magnetic field of 27-28 T required for operation at the 670 GHz at the fundamental cyclotron resonance is produced by a pulsed solenoid. The pulse duration of the magnetic field is several milliseconds. A gyrotron is driven by a 70 kV, 15 A electron beam, so the beam power is on the order of 1 MW in 10-20 ms pulses. The ratio of the orbital to axial electron velocity components is in the range of 1.2-1.3. The gyrotron is designed to operate in the TE31,8-mode. Operation in a so high-order mode results in relatively low ohmic losses (less than 10% of the radiated power). Achieved power of the outgoing radiation (210 kW) and corresponding efficiency (about 20%) represent record numbers for high-power sources of sub-THz radiation.

  10. Plant response to microwaves at 2.45 GHz

    NASA Astrophysics Data System (ADS)

    Skiles, J. W.

    2006-03-01

    The solar power satellites (SPS) concept envisions an array of satellites in Earth orbit where they will collect solar energy and beam it to Earth. One transmission method is to use microwaves at 2.45 GHz. It is uncertain what the long-term effects will be of continuous microwave energy illumination of the biosphere. An experiment was done that exposed alfalfa to continuous microwave energy at 2.45 GHz with intensities of 0.5-1.2 mW/cm 2. The hypothesis was that plants exposed to microwaves would be no different from those plants not exposed to microwaves. A tray of growing plants was illuminated with microwaves while control plants were grown behind a microwave-opaque shield. Test plants and the control plants were subjected to the same environment otherwise. The experiment was designed so that the only variable to which the test plants were subjected was microwave exposure. Precise, non-destructive measurements were taken weekly of leaf chlorophyll concentration. After 7 weeks the plants were harvested and fresh weight and dry weight were measured. Gross plant variables such as stem length and internodal distance were measured, and overall plant vigor was assessed. In all measured variables there was no difference between the control and the microwave treatment plants.

  11. Efficient synthesis of 6-O-palmitoyl-1,2-O-isopropylidene-α-D-glucofuranose in an organic solvent system by lipase-catalyzed esterification.

    PubMed

    Kobayashi, Takashi; Ehara, Taro; Mizuoka, Takanori; Adachi, Shuji

    2010-11-01

    In order to synthesize a sugar ester at high concentration, 1,2-O-isopropylidene-α-D-glucofuranose (IpGlc), which is one of the sugar acetals and is more hydrophobic than unmodified glucose, was esterified with palmitic acid at 40°C using immobilized lipase from Candida antarctica in some organic solvents or their mixtures. Acetone + t-butyl alcohol (3:1 v/v) improved both the initial reaction rate and yield after 80 h: the product reached its maximum value (240 mmol/kg solvent; ca. 110 g/kg solvent) when 400 mmol IpGlc/kg solvent and 1,200 mmol palmitic acid/kg solvent were used in this solvent mixture.

  12. A Langmuir film approach to elucidating interactions in lipid membranes: 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine/cholesterol/metal cation systems.

    PubMed

    Korchowiec, Beata; Paluch, Maria; Corvis, Yohann; Rogalska, Ewa

    2006-01-01

    The interactions between two membrane lipids, 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) and cholesterol (CHOL), were studied in Langmuir films using surface pressure isotherms and Brewster angle microscopy. The DPPE/CHOL interactions were probed for chosen monolayer and subphase (Na(+), Ca(2+)) composition at 20, 25, and 30 degrees C. The results obtained show that DPPE and CHOL are miscible for the cholesterol mol fractions x(CHOL)=0.3-0.5. Cholesterol induces condensation of the DPPE monolayers. The most significant condensation of the DPPE/CHOL monolayers was observed in the presence of Ca(2+) ions in the subphase at x(CHOL)=0.4. The negative deviation of the molecular surface area (MMA) additivity from the ideal behavior together with negative values of excess free enthalpy of mixing in the monolayers were interpreted in terms of attractive interactions between lipid molecules.

  13. Heterospin systems constructed from [Cu2Ln]3+ and [Ni(mnt)2]1-,2- Tectons: First 3p-3d-4f complexes (mnt = maleonitriledithiolato).

    PubMed

    Madalan, Augustin M; Avarvari, Narcis; Fourmigué, Marc; Clérac, Rodolphe; Chibotaru, Liviu F; Clima, Sergiu; Andruh, Marius

    2008-02-04

    New heterospin complexes have been obtained by combining the binuclear complexes [{Cu(H(2)O)L(1)}Ln(O(2)NO)(3)] or [{CuL(2)}Ln(O(2)NO)(3)] (L(1) = N,N'-propylene-di(3-methoxysalicylideneiminato); L(2) = N,N'-ethylene-di(3-methoxysalicylideneiminato); Ln = Gd(3+), Sm(3+), Tb(3+)), with the mononuclear [CuL(1)(2)] and the nickel dithiolene complexes [Ni(mnt)(2)](q)- (q = 1, 2; mnt = maleonitriledithiolate), as follows: (1)infinity[{CuL(1)}(2)Ln(O(2)NO){Ni(mnt)(2)}].Solv.CH(3)CN (Ln = Gd(3+), Solv = CH(3)OH (1), Ln = Sm(3+), Solv = CH(3)CN (2)) and [{(CH(3)OH)CuL(2)}(2)Sm(O(2)NO)][Ni(mnt)(2)] (3) with [Ni(mnt)2]2-, [{(CH(3)CN)CuL(1)}(2)Ln(H(2)O)][Ni(mnt)(2)]3.2CH(3)CN (Ln = Gd(3+) (4), Sm(3+) (5), Tb(3+) (6)), and [{(CH(3)OH)CuL(2)}{CuL(2)}Gd(O(2)NO){Ni(mnt)(2)}][Ni(mnt)(2)].CH(2)Cl(2) (7) with [Ni(mnt))(2]*-. Trinuclear, almost linear, [CuLnCu] motifs are found in all the compounds. In the isostructural 1 and 2, two trans cyano groups from a [Ni(mnt)2]2- unit bridge two trimetallic nodes through axial coordination to the Cu centers, thus leading to the establishment of infinite chains. 3 is an ionic compound, containing discrete [{(CH(3)OH)CuL(2)}(2)Sm(O(2)NO)](2+) cations and [Ni(mnt)(2)](2-) anions. Within the series 4-6, layers of discrete [CuLnCu](3+) motifs alternate with stacks of interacting [Ni(mnt)(2)](*-) radical anions, for which two overlap modes, providing two different types of stacks, can be disclosed. The strength of the intermolecular interactions between the open-shell species is estimated through extended Hückel calculations. In compound 7, [Ni(mnt)(2)](*-) radical anions coordinate group one of the Cu centers of a trinuclear [Cu(2)Gd] motif through a CN, while discrete [Ni(mnt)(2)](*-) units are also present, overlapping in between, but also with the coordinated ones. Furthermore, the [Cu(2)Gd] moieties dimerize each other upon linkage by two nitrato groups, both acting as chelate toward the gadolinium ion from one unit and monodentate toward a

  14. Development of a 150-GHz MMIC Module Prototype for Large-Scale CMB Radiation

    NASA Technical Reports Server (NTRS)

    Kangaslahti, Pekka P.; Samoska, Lorene A.; Gaier, Todd C.; Soria, Mary M.; Lau, Judy M.; Sieth, Matthew M.; VanWinkle, Daniel; Tantawi, Sami

    2011-01-01

    HEMT-based receiver arrays with excellent noise and scalability are already starting to be manufactured at 100 GHz, but the advances in technology should make it possible to develop receiver modules with even greater operation frequency up to 200 GHz. A prototype heterodyne amplifier module has been developed for operation from 140 to 170 GHz using monolithic millimeter-wave integrated circuit (MMIC) low-noise InP high electron mobility transistor (HEMT) amplifiers. The compact, scalable module is centered on the 150-GHz atmospheric window using components known to operate well at these frequencies. Arrays equipped with hundreds of these modules can be optimized for many different astrophysical measurement techniques, including spectroscopy and interferometry. This module is a heterodyne receiver module that is extremely compact, and makes use of 35-nm InP HEMT technology, and which has been shown to have excellent noise temperatures when cooled cryogenically to 30 K. This reduction in system noise over prior art has been demonstrated in commercial mixers (uncooled) at frequencies of 160-180 GHz. The module is expected to achieve a system noise temperature of 60 K when cooled. An MMIC amplifier module has been designed to demonstrate the feasibility of expanding heterodyne amplifier technology to the 140 to 170-GHz frequency range for astronomical observations. The miniaturization of many standard components and the refinement of RF interconnect technology have cleared the way to mass-production of heterodyne amplifier receivers, making it a feasible technology for many large-population arrays. This work furthers the recent research efforts in compact coherent receiver modules, including the development of the Q/U Imaging ExperimenT (QUIET) modules centered at 40 and 90 GHz, and the production of heterodyne module prototypes at 90 GHz.

  15. AMMONIA AND CO OBSERVATIONS TOWARD LOW-LUMINOSITY 6.7 GHz METHANOL MASERS

    SciTech Connect

    Wu, Y. W.; Xu, Y.; Yang, J.; Zhang, S. B.; Pandian, J. D.; Henkel, C.; Menten, K. M.

    2010-09-01

    To investigate whether distinctions exist between low- and high-luminosity Class II 6.7 GHz methanol masers, we have undertaken multi-line mapping observations of various molecular lines, including the NH{sub 3} (1,1), (2,2), (3,3), (4,4), and {sup 12}CO (1-0) transitions, toward a sample of nine low-luminosity 6.7 GHz masers and {sup 12}CO (1-0) observations toward a sample of eight high-luminosity 6.7 GHz masers, for which we already had NH{sub 3} spectral line data. Emission in the NH{sub 3} (1,1), (2,2), and (3,3) transitions was detected in eight out of nine low-luminosity maser sources, in which 14 cores were identified. We derive densities, column densities, temperatures, core sizes, and masses of both low- and high-luminosity maser regions. A comparative analysis of the physical quantities reveals marked distinctions between the low-luminosity and high-luminosity groups: in general, cores associated with high-luminosity 6.7 GHz masers are larger and more massive than those traced by low-luminosity 6.7 GHz masers; regions traced by the high-luminosity masers have larger column densities but lower densities than those of the low-luminosity maser regions. Further, strong correlations between 6.7 GHz maser luminosity and NH{sub 3} (1,1) and (2,2) line widths are found, indicating that internal motions in high-luminosity maser regions are more energetic than those in low-luminosity maser regions. A {sup 12}CO (1-0) outflow analysis also shows distinctions in that outflows associated with high-luminosity masers have wider line wings and larger sizes than those associated with low-luminosity masers.

  16. A 20 GHz Active Receive Slot Array

    NASA Technical Reports Server (NTRS)

    Tulintseff, A. N.; Lee, K.; Sukamto, L.; Chew, W.

    1994-01-01

    A 20 GHz active receive slot array has been developed for operation in the downlink frequency band of NASA's Advanced Communication Technology Satellite (ACTS) for the ACTS Mobile Terminal (AMT) project. The AMT is to demonstrate voice and data communication between a mobile terminal in Los Angeles, California, and a fixed terminal in Cleveland, Ohio, via the ACTS satellite.

  17. A 20 GHz Active Receive Slot Array

    NASA Technical Reports Server (NTRS)

    Tulintseff, A. N.; Lee, K.; Sukamto, L.; Chew, W.

    1994-01-01

    A 20 GHz active receive slot array has been developed for operation in the downlink frequency band of NASA's Advanced Communication Technology Satellite (ACTS) for the ACTS Mobile Terminal (AMT) project. The AMT is to demonstrate voice and data communication between a mobile terminal in Los Angeles, California, and a fixed terminal in Cleveland, Ohio, via the ACTS satellite.

  18. 60 GHz Tapered Transmission Line Resonators

    DTIC Science & Technology

    2008-09-15

    DARPA TEAM program (contract no. DAAB07-02-1- L428 ), Motorola, and the UC-Micro program. 60 GHz Tapered Transmission Line Resonators by...0403427, wafer fabrication donation by STMicroelectronics, DARPA TEAM program (con- tract no. DAAB07-02-1- L428 ), Motorola, and the UC-Micro program. 1

  19. The Zeeman Effect in the 44 GHz Class I Methanol Maser Line toward DR21(OH)

    NASA Astrophysics Data System (ADS)

    Momjian, E.; Sarma, A. P.

    2017-01-01

    We report detection of the Zeeman effect in the 44 GHz Class I methanol maser line, toward the star-forming region DR21(OH). In a 219 Jy beam‑1 maser centered at an LSR velocity of 0.83 km s‑1, we find a 20-σ detection of zBlos = 53.5 ± 2.7 Hz. If 44 GHz methanol masers are excited at n ∼ 107–8 cm‑3, then the B versus n1/2 relation would imply, from comparison with Zeeman effect detections in the CN(1 ‑ 0) line toward DR21(OH), that magnetic fields traced by 44 GHz methanol masers in DR21(OH) should be ∼10 mG. Combined with our detected zBlos = 53.5 Hz, this would imply that the value of the 44 GHz methanol Zeeman splitting factor z is ∼5 Hz mG‑1. Such small values of z would not be a surprise, as the methanol molecule is non-paramagnetic, like H2O. Empirical attempts to determine z, as demonstrated, are important because there currently are no laboratory measurements or theoretically calculated values of z for the 44 GHz CH3OH transition. Data from observations of a larger number of sources are needed to make such empirical determinations robust.

  20. Commissioning of the superconducting ECR ion source VENUS at 18 GHz

    SciTech Connect

    Leitner, Daniela; Abbott, Steven R.; Dwinell, Roger D.; Leitner, Matthaeus; Taylor, Clyde E.; Lyneis, Claude M.

    2004-06-01

    During the last year, the VENUS ECR ion source was commissioned at 18 GHz and preparations for 28 GHz operation are now underway. During the commissioning phase with 18 GHz, tests with various gases and metals have been performed with up to 2000 W RF power. The ion source performance is very promising [1,2]. VENUS (Versatile ECR ion source for Nuclear Science) is a next generation superconducting ECR ion source, designed to produce high current, high charge state ions for the 88-Inch Cyclotron at the Lawrence Berkeley National Laboratory. VENUS also serves as the prototype ion source for the RIA (Rare Isotope Accelerator) front end. The goal of the VENUS ECR ion source project as the RIA R&D injector is the production of 240e{micro}A of U{sup 30+}, a high current medium charge state beam. On the other hand, as an injector ion source for the 88-Inch Cyclotron the design objective is the production of 5e{micro}A of U{sup 48+}, a low current, very high charge state beam. To meet these ambitious goals, VENUS has been designed for optimum operation at 28 GHz. This frequency choice has several design consequences. To achieve the required magnetic confinement, superconducting magnets have to be used. The size of the superconducting magnet structure implies a relatively large plasma volume. Consequently, high power microwave coupling becomes necessary to achieve sufficient plasma heating power densities. The 28 GHz power supply has been delivered in April 2004.