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Sample records for activated high gain

  1. High power VCSEL device with periodic gain active region

    Ning, Y. Q., II; Qin, L.; Sun, Y. F.; Li, T.; Cui, J. J.; Peng, B.; Liu, G. Y.; Zhang, Y.; Liu, Y.; Wang, L. J.; Cui, D. F.; Xu, Z. Y.

    2007-11-01

    High power vertical cavity surface emitting lasers with large aperture have been fabricated through improving passivation, lateral oxidation and heat dissipation techniques. Different from conventional three quantum well structure, a periodic gain active region with nine quantum wells was incorporated into the VCSEL structure, with which high efficiency and high power operation were expected. The nine quantum wells were divided into three groups with each of them located at the antinodes of the cavity to enhance the coupling between the optical field and the gain region. Large aperture and bottom-emitting configuration was used to improve the beam quality and the heat dissipation. A maximum output power of 1.4W was demonstrated at CW operation for a 400μm-diameter device. The lasing wavelength shifted to 995.5nm with a FWHM of 2nm at a current of 4.8A due to the internal heating and the absence of active water cooling. A ring-shape farfield pattern was induced by the non-homogeneous lateral current distribution in large diameter device. The light intensity at the center of the ring increased with increasing current. A symmetric round light spot at the center and single transverse mode operation with a divergence angle of 16° were observed with current beyond 4.8A.

  2. Photon-activated charge domain in high-gain photoconductive switches

    Wei Shi(施卫); Huiying Dai(戴慧莹); Xiaowei Sun(孙小卫)

    2003-01-01

    We report our experimental observation of charge domain oscillation in semi-insulating GaAs photoconductive semiconductor switches (PCSSs). The high-gain PCSS is intrinsically a photon-activated charge domain device. It is the photon-activated carriers that satisfy the requirement of charge domain formation on carrier concentration and device length product of 1012 cm-2. We also show that, because of the repeated process of domain formation, the domain travels with a compromised speed of electron saturation velocity and the speed of light. As a result, the transit time of charge domains in PCSS is much shorter than that of traditional Gunn domains.

  3. Instrumentation amplifier implements second-order active low-pass filter with high gain factor

    A single-ended second-order active low-pass filter can simultaneously provide high gain factor and dc voltage subtraction. This makes it possible to reduce the number of components and signal processing stages needed in an application where small voltage changes are measured on the top of large dc voltage masked by a large amplitude oscillating carrier. The filter described in this paper is constructed from a conventional 3-op-amp instrumentation amplifier and five passive circuit elements. (technical design note)

  4. Arctigenin Inhibits Adipogenesis by Inducing AMPK Activation and Reduces Weight Gain in High-Fat Diet-Induced Obese Mice.

    Han, Yo-Han; Kee, Ji-Ye; Park, Jinbong; Kim, Hye-Lin; Jeong, Mi-Young; Kim, Dae-Seung; Jeon, Yong-Deok; Jung, Yunu; Youn, Dong-Hyun; Kang, JongWook; So, Hong-Seob; Park, Raekil; Lee, Jong-Hyun; Shin, Soyoung; Kim, Su-Jin; Um, Jae-Young; Hong, Seung-Heon

    2016-09-01

    Although arctigenin (ARC) has been reported to have some pharmacological effects such as anti-inflammation, anti-cancer, and antioxidant, there have been no reports on the anti-obesity effect of ARC. The aim of this study is to investigate whether ARC has an anti-obesity effect and mediates the AMP-activated protein kinase (AMPK) pathway. We investigated the anti-adipogenic effect of ARC using 3T3-L1 pre-adipocytes and human adipose tissue-derived mesenchymal stem cells (hAMSCs). In high-fat diet (HFD)-induced obese mice, whether ARC can inhibit weight gain was investigated. We found that ARC reduced weight gain, fat pad weight, and triglycerides in HFD-induced obese mice. ARC also inhibited the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα) in in vitro and in vivo. Furthermore, ARC induced the AMPK activation resulting in down-modulation of adipogenesis-related factors including PPARγ, C/EBPα, fatty acid synthase, adipocyte fatty acid-binding protein, and lipoprotein lipase. This study demonstrates that ARC can reduce key adipogenic factors by activating the AMPK in vitro and in vivo and suggests a therapeutic implication of ARC for obesity treatment. J. Cell. Biochem. 117: 2067-2077, 2016. © 2016 Wiley Periodicals, Inc. PMID:26852013

  5. Review of High Gain FELs

    For understanding on basic radiation mechanism of the high-gain FEL based on SASE, the author presents electron-crystal interpretation of FEL radiation. In the electron-crystal, electrons are localized at regularly spaced multi-layers, which represents micro-bunching, whose spacing is equal to the radiation wavelength, and the multi-layers are perpendicular to beam axis, thus, diffracted wave creates Bragg's spots in forward and backward directions. Due to the Doppler's effect, frequency of the back-scattered wave is up-converted, generates forwardly focused X-ray. The Bragg's effect contributes focusing the X-ray beam into a spot, thus peak power becomes extremely higher by factor of typically 107. This is the FEL radiation. As well known, the total numbers of scattered photons in Bragg's spots is equal to the total elastic scattering photons from the atoms contained in the crystal. Therefore, total power in the FEL laser is same as the spontaneous radiation power from the undulator for the same beam parameter. The FEL radiation phenomenon is simple interference effect. In today's presentations, we use the laser pointer, and we frequently experience difficulty in pointing precisely or steadily in one place on the screen, since the laser spot is very small and does not spread. Exactly same to this, X-ray FEL is a highly focused beam, and pointing stability dominates productivity of experiment, thus we need special care on beam stability from linear accelerator

  6. High current gain transistor laser

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-06-01

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge.

  7. Active Microwave Metamaterials Incorporating Ideal Gain Devices

    Hao Xin

    2010-12-01

    Full Text Available Incorporation of active devices/media such as transistors for microwave and gain media for optics may be very attractive for enabling desired low loss and broadband metamaterials. Such metamaterials can even have gain which may very well lead to new and exciting physical phenomena. We investigate microwave composite right/left-handed transmission lines (CRLH-TL incorporating ideal gain devices such as constant negative resistance. With realistic lumped element values, we have shown that the negative phase constant of this kind of transmission lines is maintained (i.e., left-handedness kept while gain can be obtained (negative attenuation constant of transmission line simultaneously. Possible implementation and challenging issues of the proposed active CRLH-TL are also discussed.

  8. High-Performance 1.55-µm Superluminescent Diode Based on Broad Gain InAs/InGaAlAs/InP Quantum Dash Active Region

    Khan, Mohammed Zahed Mustafa

    2014-08-01

    We report on the high-performance characteristics from superluminescent diodes (SLDs) based on four-stack InAs/InGaAlAs chirped-barrier thickness quantum dash (Qdash) in a well structure. The active region exhibits a measured broad gain spectrum of 140 nm, with a peak modal gain of ~41 cm-1. The noncoated two-section gainabsorber broad-area and ridge-waveguide device configuration exhibits an output power of > 20 mW and > 12 mW, respectively. The corresponding -3-dB bandwidths span ~82 nm and ~72 nm, with a small spectral ripple of <; 0.2 dB, related largely to the contribution from dispersive height dash ensembles of the highly inhomogeneous active region. These C-L communication band devices will find applications in various cross-disciplinary fields of optical metrology, optical coherent tomography, etc.

  9. Progress in high gain inertial confinement fusion

    The author reviews the progress in laboratory high gain inertial confinement fusion (ICF), including ICF capsule physics, high-energy-density science, inertial fusion energy, the National Ignition Facility (NIF) and its design of ignition targets and the peta watt laser breakthrough. High power laser, particle beam, and pulsed power facilities around the world have established the new laboratory field of high-energy- density plasma physics and have furthered development of inertial fusion. New capabilities such as those provided by high-brightness peta watt lasers have enabled the study of matter feasible in conditions previously unachievable on earth. Science and technology developed in inertial fusion research have found near-term commercial use and have enabled steady progress toward the goal of fusion ignition and high gain in the laboratory, and have opened up new fields of study for the 21 st century

  10. Gain measurement of high power FEL

    We have developed a novel method to measure a gain of a free electron laser (FEL) with a modulation spectroscopy. An an intensity of a FEL grows over eight order from spontaneous radiation to saturation, we use a silicon (Si) bolometer which shows a linear response to this large intensity region. The Si bolometer measures the integrated intensity, energy of the FEL macropulse generated with changing the number of amplifications repeatedly in two steps, then a simple Fourier analysis of this measured energy finds values synchronized to the modulation and including the energy, the power and the gain of the FEL macropulse. This measurement and analysis are continued with the number of amplification increased, so we derive the FEL gain variation with time and the developments of the FEL energy and power. Today, the THz-FEL of ISIR, Osaka Univ. has generated a high power FEL with electron bunches have four times charges of the conventional FEL mode. We measure the gain of this mode with the new method as the one of the evaluation of the specification. The measured gain variation shows its maximum value, ∼200% and a falling process because of the FEL saturation. (author)

  11. AN OVERVIEW OF THE DEVELOPMENT OF LOW GAIN FEEDBACK AND LOW-AND-HIGH GAIN FEEDBACK

    Zongli LIN

    2009-01-01

    Low gain feedback refers to certain families of stabilizing state feedback gains that are parameterized in a scalar and go to zero as the scalar decreases to zero. Low gain feedback was initially proposed to achieve semi-global stabilization of linear systems subject to input saturation. It was then combined with high gain feedback in different ways for solving various control problems. The resulting feedback laws are referred to as low-and-high gain feedback. Since the introduction of low gain feedback in the context of semi-global stabilization of linear systems subject to input saturation,there has been effort to develop alternative methods for low gain design, to characterize key features of low gain feedback, and to explore new applications of the low gain and low-and-high gain feedback.This paper reviews the developments in low gain and low-and-high gain feedback designs.

  12. Visual Contrast Sensitivity Improvement by Right Frontal High-Beta Activity Is Mediated by Contrast Gain Mechanisms and Influenced by Fronto-Parietal White Matter Microstructure.

    Quentin, Romain; Elkin Frankston, Seth; Vernet, Marine; Toba, Monica N; Bartolomeo, Paolo; Chanes, Lorena; Valero-Cabré, Antoni

    2016-06-01

    Behavioral and electrophysiological studies in humans and non-human primates have correlated frontal high-beta activity with the orienting of endogenous attention and shown the ability of the latter function to modulate visual performance. We here combined rhythmic transcranial magnetic stimulation (TMS) and diffusion imaging to study the relation between frontal oscillatory activity and visual performance, and we associated these phenomena to a specific set of white matter pathways that in humans subtend attentional processes. High-beta rhythmic activity on the right frontal eye field (FEF) was induced with TMS and its causal effects on a contrast sensitivity function were recorded to explore its ability to improve visual detection performance across different stimulus contrast levels. Our results show that frequency-specific activity patterns engaged in the right FEF have the ability to induce a leftward shift of the psychometric function. This increase in visual performance across different levels of stimulus contrast is likely mediated by a contrast gain mechanism. Interestingly, microstructural measures of white matter connectivity suggest a strong implication of right fronto-parietal connectivity linking the FEF and the intraparietal sulcus in propagating high-beta rhythmic signals across brain networks and subtending top-down frontal influences on visual performance. PMID:25899709

  13. High gain observer for embedded Acrobot

    Anderle, Milan; Čelikovský, Sergej

    Cape Town: IFAC, 2014, s. 2818-2823. ISBN 978-3-902823-62-5. [The 19th World Congress of the IFAC /2014/. Cape Town (ZA), 24.08.2014-29.08.2014] R&D Projects: GA ČR(CZ) GAP103/12/1794 Institutional support: RVO:67985556 Keywords : Underactuated mechanical systems * Embedding * High gain observer Subject RIV: BC - Control Systems Theory

  14. Ignition and high gain with ultrapowerful lasers

    Ultrahigh intensity lasers can potentially be used in conjunction with conventional fusion lasers to ignite inertial confinement fusion (ICF) capsules with a total energy of a few tens of kilojoules of laser light, and can possibly lead to high gain with as little as 100 kJ. A scheme is proposed with three phases. First, a capsule is imploded as in the conventional approach to inertial fusion to assemble a high-density fuel configuration. Second, a hole is bored through the capsule corona composed of ablated material, as the critical density is pushed close to the high-density core of the capsule by the ponderomotive force associated with high-intensity laser light. Finally, the fuel is ignited by suprathermal electrons, produced in the high-intensity laser--plasma interactions, which then propagate from critical density to this high-density core. This new scheme also drastically reduces the difficulty of the implosion, and thereby allows lower quality fabrication and less stringent beam quality and symmetry requirements from the implosion driver. The difficulty of the fusion scheme is transferred to the technological difficulty of producing the ultrahigh-intensity laser and of transporting this energy to the fuel

  15. Physical Activity and Gestational Weight Gain in Hispanic Women

    Chasan-Taber, Lisa; Silveira, Marushka; Lynch, Kristine E.; Pekow, Penelope; Solomon, Caren G.; Markenson, Glenn

    2013-01-01

    Objective Hispanic women have high rates of excessive and inadequate gestational weight gain (GWG) according to Institute of Medicine (IOM) guidelines. Observational studies suggest that physical activity may be associated with GWG but have been conflicting and were largely conducted in non-Hispanic white populations. Design and Methods We prospectively evaluated the association between physical activity and compliance with GWG guidelines, total GWG, and rate of GWG among 1,276 Hispanic parti...

  16. Physical Activity and Gestational Weight Gain in Hispanic Women

    Chasan-Taber, Lisa; Silveira, Marushka; Lynch, Kristine E.; Pekow, Penelope; Solomon, Caren G.; Markenson, Glenn

    2013-01-01

    Objective: Hispanic women have high rates of excessive and inadequate gestational weight gain (GWG) according to Institute of Medicine (IOM) guidelines. Observational studies suggest that physical activity may be associated with GWG but have been conflicting and were largely conducted in non-Hispanic white populations. Design and Methods We prospectively evaluated the association between physical activity and compliance with GWG guidelines, total GWG, and rate of GWG among 1,276 Hispanic part...

  17. High-Gain High-Field Fusion Plasma

    Li, Ge

    2015-10-01

    A Faraday wheel (FW)—an electric generator of constant electrical polarity that produces huge currents—could be implemented in an existing tokamak to study high-gain high-field (HGHF) fusion plasma, such as the Experimental Advanced Superconducting Tokamak (EAST). HGHF plasma can be realized in EAST by updating its pulsed-power system to compress plasma in two steps by induction fields; high gains of the Lawson trinity parameter and fusion power are both predicted by formulating the HGHF plasma. Both gain rates are faster than the decrease rate of the plasma volume. The formulation is checked by earlier ATC tests. Good agreement between theory and tests indicates that scaling to over 10 T at EAST may be possible by two-step compressions with a compression ratio of the minor radius of up to 3. These results point to a quick new path of fusion plasma study, i.e., simulating the Sun by EAST.

  18. Physical activity and weight gain during pregnancy

    Haakstad, Lene Annette Hagen

    2010-01-01

    A low level of daily PA and regular recreational exercise was shown in the present study of pregnant women in Oslo. There was a decline in exercise intensity, duration and frequency from before pregnancy and throughout the course of pregnancy. Walking was the most common exercise mode. The results of the multivariate analysis showed that women who decreased regular exercise in the 3rd trimester had higher weight gain and reported to have no social role models with respect to ex...

  19. Gain and noise in very high gain avalanche photodiodes: Theory and experiment

    Large area silicon avalanche photodiodes (APDs) have been fabricated with maximum avalanche gains exceeding 10,000 and excellent signal to noise ratios. A model of device performance has been developed in which previously developed general expressions are numerically integrated using actual fabrication parameters. The gain, statistical fluctuations in the gain, electronic noise, and total peak broadening have been computed using this model. The results are in good agreement with measurements. The parameter keff was found to be 7.2 x 10-4, allowing a high signal to noise ratio at gains of several thousand

  20. Extended High-Gain Observer for Mars Entry Guidance

    Pingyuan Cui

    2013-02-01

    Full Text Available To deliver a Mars entry vehicle to the prescribed parachute deployment point, active entry guidance is essential. This paper addresses the problem of Mars atmospheric entry guidance through drag tracking method with extended high gain observer. First, an extended high gain observer combined with feedback linearization is applied in drag tracking for Mars entry longitudinal guidance.  The observer estimates the drag and drag rate for drag tracking, estimates the perturbation due to model uncertainty and disturbance, and compensate for the perturbation by canceling its estimate. Then, bank reversal is adopted in the lateral plane to reduce the cross-range error. Finally, Mars entry simulation is performed to assess the performance of the adaptive guidance law. The results demonstrate that the proposed guidance law exhibits good performance.

  1. High gain durable anti-reflective coating

    Maghsoodi, Sina; Brophy, Brenor L.; Colson, Thomas E.; Gonsalves, Peter R.; Abrams, Ze' ev R.

    2016-07-26

    Disclosed herein are polysilsesquioxane-based anti-reflective coating (ARC) compositions, methods of preparation, and methods of deposition on a substrate. In one embodiment, the polysilsesquioxane of this disclosure is prepared in a two-step process of acid catalyzed hydrolysis of organoalkoxysilane followed by addition of tetralkoxysilane that generates silicone polymers with >40 mol % silanol based on Si-NMR. These high silanol siloxane polymers are stable and have a long shelf-life in polar organic solvents at room temperature. Also disclosed are low refractive index ARC made from these compositions with and without additives such as porogens, templates, thermal radical initiator, photo radical initiators, crosslinkers, Si--OH condensation catalyst and nano-fillers. Also disclosed are methods and apparatus for applying coatings to flat substrates including substrate pre-treatment processes, coating processes and coating curing processes including skin-curing using hot-air knives. Also disclosed are coating compositions and formulations for highly tunable, durable, highly abrasion-resistant functionalized anti-reflective coatings.

  2. Nonlinear Gain Saturation in Active Slow Light Photonic Crystal Waveguides

    Chen, Yaohui; Mørk, Jesper

    2013-01-01

    We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated.......We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated....

  3. Simulation of Nonlinear Gain Saturation in Active Photonic Crystal Waveguides

    Chen, Yaohui; Mørk, Jesper

    2012-01-01

    In this paper we present a theoretical analysis of slowlight enhanced traveling wave amplification in an active semiconductor Photonic crystal waveguides. The impact of group index on nonlinear modal gain saturation is investigated.......In this paper we present a theoretical analysis of slowlight enhanced traveling wave amplification in an active semiconductor Photonic crystal waveguides. The impact of group index on nonlinear modal gain saturation is investigated....

  4. A wide range and high speed automatic gain control

    Automatic gain control (AGC) techniques have been largely used since the beginning of electronics, but in most of the applications the dynamic response is slow compared with the carrier frequency. The problem of developing an automatic gain control with high dynamic response and wide control range simultaneously is analyzed in this work. An ideal gain control law, with the property that the total loop gain remains constant independent of the carrier amplitude, is obtained. The resulting AGC behavior is compared by computer simulations with a linear multiplier AGC. The ideal gain control law can be approximated using a transconductance amplifier. A practical circuit that has been used at CERN in the radio frequency loops of the Booster Synchrotron is presented. The circuit has high speed and 80-dB gain control range

  5. Study on high gain broadband optical parametric chirped pulse amplification

    Optical parametric chirped pulse amplification has apparent advantages over the current schemes for high energy ultrashort pulse amplification. High gain in a single pass amplification, small B-integral, low heat deposition, high contrast ratio and, especially the extremely broad gain bandwidth with large-size crystals available bring people new hope for over multi-PW level at which the existing Nd:glass systems suffered difficulties. In this paper we present simulation and experimental studies for a high gain optical parametric chirped pulse amplification system which may be used as a preamplifier to replace the current complicated regenerative system or multi-pass Ti:sapphire amplifiers. Investigations on the amplification bandwidth and gain with BBO are performed. Analysis and discussions are also given. (author)

  6. Recent Progress in High-Gain FEL Theory

    High-gain free electron lasers (FEL) are being developed as extremely bright x-ray sources of a next-generation radiation facility. In this paper, we review the basic theory and the recent progress in understanding the startup, the exponential growth and the saturation of the high-gain process, emphasizing the self-amplified spontaneous emission (SASE). We will also discuss how the FEL performance may be affected by various errors and wakefield effects in the undulator

  7. Design of a high-gain flux-compression generator

    The current gain of a high-gain, high-explosive helical magnetic-flux-compression generator (HEG) is limited both by nonuniformities in stator expansion and by armature-stator misalignment. The authors report on their work to achieve three goals: first, an output current of at least 2 MA with a current gain greater than 1000 to drive a 150-to 300-nH load; second, a generator with an acceptably small volume and length; and finally, generator output of a reliable magnitude. To achieve these performance goals, the authors had to pay careful attention to design aspects of mechanical tolerances. They increased the diameter of the armature winding wire to limit the action integral at a given location along it to a value below the surface melting point

  8. Radiation Response of Emerging High Gain, Low Noise Detectors

    Becker, Heidi N.; Farr, William H; Zhu, David Q.

    2007-01-01

    Data illustrating the radiation response of emerging high gain, low noise detectors are presented. Ionizing dose testing of silicon internal discrete avalanche photodiodes, and 51-MeV proton testing of InGaAs/InAlAs avalanche photodiodes operated in Geiger mode are discussed.

  9. Best Practices for Achieving High, Rapid Reading Gains

    Carbo, Marie

    2008-01-01

    The percentage of students who read at the proficient level on the National Assessment of Educational Progress (NAEP) has not improved, and is appallingly low. In order for students to achieve high reading gains and become life-long readers, reading comprehension and reading enjoyment must be the top two goals. This article presents several…

  10. Design of a high linearity and high gain accuracy analog baseband circuit for DAB receiver

    An analog baseband circuit of high linearity and high gain accuracy for a digital audio broadcasting receiver is implemented in a 0.18-μm RFCMOS process. The circuit comprises a 3rd-order active-RC complex filter (CF) and a programmable gain amplifier (PGA). An automatic tuning circuit is also designed to tune the CF's pass band. Instead of the class-A fully differential operational amplifier (FDOPA) adopted in the conventional CF and PGA design, a class-AB FDOPA is specially employed in this circuit to achieve a higher linearity and gain accuracy for its large current swing capability with lower static current consumption. In the PGA circuit, a novel DC offset cancellation technique based on the MOS resistor is introduced to reduce the settling time significantly. A reformative switching network is proposed, which can eliminate the switch resistor's influence on the gain accuracy of the PGA. The measurement result shows the gain range of the circuit is 10–50 dB with a 1-dB step size, and the gain accuracy is less than ±0.3 dB. The OIP3 is 23.3 dBm at the gain of 10 dB. Simulation results show that the settling time is reduced from 100 to 1 ms. The image band rejection is about 40 dB. It only draws 4.5 mA current from a 1.8 V supply voltage. (semiconductor integrated circuits)

  11. Ultra-high gain diffusion-driven organic transistor

    Torricelli, Fabrizio; Colalongo, Luigi; Raiteri, Daniele; Kovács-Vajna, Zsolt Miklós; Cantatore, Eugenio

    2016-02-01

    Emerging large-area technologies based on organic transistors are enabling the fabrication of low-cost flexible circuits, smart sensors and biomedical devices. High-gain transistors are essential for the development of large-scale circuit integration, high-sensitivity sensors and signal amplification in sensing systems. Unfortunately, organic field-effect transistors show limited gain, usually of the order of tens, because of the large contact resistance and channel-length modulation. Here we show a new organic field-effect transistor architecture with a gain larger than 700. This is the highest gain ever reported for organic field-effect transistors. In the proposed organic field-effect transistor, the charge injection and extraction at the metal-semiconductor contacts are driven by the charge diffusion. The ideal conditions of ohmic contacts with negligible contact resistance and flat current saturation are demonstrated. The approach is general and can be extended to any thin-film technology opening unprecedented opportunities for the development of high-performance flexible electronics.

  12. Interleukin-18 activates skeletal muscle AMPK and reduces weight gain and insulin resistance in mice

    Madsen, Birgitte Lindegaard; Matthews, Vance B; Brandt, Claus;

    2013-01-01

    receptor (IL-18R(-/-)), fed a standard chow or high fat diet (HFD). We next performed gain of function experiments in skeletal muscle, in vitro, ex vivo and in vivo. We show that IL-18 is implicated in metabolic homeostasis, inflammation and insulin resistance via mechanisms involving the activation of......-18 into skeletal muscle activated AMPK and concomitantly inhibited high fat diet-induced weight gain. In summary IL-18 enhances AMPK signaling and lipid oxidation in skeletal muscle implicating IL-18 in metabolic homeostasis....

  13. 20 CFR 416.972 - What we mean by substantial gainful activity.

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false What we mean by substantial gainful activity... Activity § 416.972 What we mean by substantial gainful activity. Substantial gainful activity is work... or profit, whether or not a profit is realized. (c) Some other activities. Generally, we do...

  14. 20 CFR 404.1572 - What we mean by substantial gainful activity.

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false What we mean by substantial gainful activity... Activity § 404.1572 What we mean by substantial gainful activity. Substantial gainful activity is work... or profit, whether or not a profit is realized. (c) Some other activities. Generally, we do...

  15. High-gain, high-bandwidth, rail-to-rail, constant-gm CMOS operational amplifier

    Huang, Hong-Yi; Wang, Bo-Ruei

    2013-01-01

    This study presents a high-gain, high-bandwidth, constant-gm , rail-to-rail operational amplifier (op-amp). The constant transconductance is improved with a source-to-bulk bias control of an input pair. A source degeneration scheme is also adapted to the output stage for receiving wide input range without degradation of the gain. Additionally, several compensation schemes are employed to enhance the stability. A test chip is fabricated in a 0.18 µm complementary metal-oxide semiconductor process. The active area of the op-amp is 181 × 173 µm2 and it consumes a power of 2.41 mW at a supply voltage of 1.8 V. The op-amp achieves a dc gain of 94.3 dB and a bandwidth of 45 MHz when the output capacitive load is connected to an effective load of 42.5 pF. A class-AB output stage combining a slew rate (SR) boost circuit provides a sinking current of 6 mA and an SR of 17 V/µs.

  16. Slow-light-enhanced gain in active photonic crystal waveguides

    Ek, Sara; Hansen, Per Lunnemann; Chen, Yaohui;

    2014-01-01

    , which would have interesting application prospects, for example enabling ultra-compact optical amplifiers for integration in photonic chips. Here we experi- mentally investigate the gain of a photonic crystal membrane structure with embedded quantum wells. We find that by solely changing the photonic...... crystal structural parameters, the maximum value of the gain coefficient can be increased compared with a ridge waveguide structure and at the same time the spectral position of the peak gain be controlled. The experimental results are in qualitative agreement with theory and show that gain values similar...

  17. Balancing high gain and bandwidth in multilayer organic photodetectors with tailored carrier blocking layers

    We present detailed studies of the high photocurrent gain behavior in multilayer organic photodiodes containing tailored carrier blocking layers we reported earlier in a Letter [W. T. Hammond and J. Xue, Appl. Phys. Lett. 97, 073302 (2010)], in which a high photocurrent gain of up to 500 was attributed to the accumulation of photogenerated holes at the anode/organic active layer interface and the subsequent drastic increase in secondary electron injection from the anode. Here, we show that both the hole-blocking layer structure and layer thickness strongly influence the magnitude of the photocurrent gain. Temporal studies revealed that the frequency response of such devices is limited by three different processes with lifetimes of 10 μs, 202 μs, and 2.72 ms for the removal of confined holes, which limit the 3 dB bandwidth of these devices to 1.4 kHz. Furthermore, the composition in the mixed organic donor-acceptor photoactive layer affects both gain and bandwidth, which is attributed to the varying charge transport characteristics, and the optimal gain-bandwidth product is achieved with approximately 30% donor content. Finally, these devices show a high dynamic range of more than seven orders of magnitude, although the photocurrent shows a sublinear dependence on the incident optical power

  18. High-gain nonlinear observer for simple genetic regulation process

    Torres, L. A.; Ibarra-Junquera, V.; Escalante-Minakata, P.; Rosu, H. C.

    2007-07-01

    High-gain nonlinear observers occur in the nonlinear automatic control theory and are in standard usage in chemical engineering processes. We apply such a type of analysis in the context of a very simple one-gene regulation circuit. In general, an observer combines an analytical differential-equation-based model with partial measurement of the system in order to estimate the non-measured state variables. We use one of the simplest observers, that of Gauthier et al., which is a copy of the original system plus a correction term which is easy to calculate. For the illustration of this procedure, we employ a biological model, recently adapted from Goodwin's old book by De Jong, in which one plays with the dynamics of the concentrations of the messenger RNA coding for a given protein, the protein itself, and a single metabolite. Using the observer instead of the metabolite, it is possible to rebuild the non-measured concentrations of the mRNA and the protein.

  19. Development of high gain photodiode array based on commercial CMOS process

    Developing photodiodes in commercial CMOS process and integrating it with readout electronics without any process modification involves formidable challenges. Due to low resistivity of the wafer used in commercial CMOS process, the junction capacitance per area of the PN junction is quite large thereby limiting the size of the active area of the photodiode leading to degradation in high speed response. On the contrary, the sensitivity and quantum efficiency of the optical detector tends to improve with increase in active area of the detector. The major challenge in designing high gain photodiode in sub micron CMOS technology is to avoid the premature perimeter edge breakdown or the soft breakdown. This paper reports two different design approaches of high gain photodiode arrays in commercial 0.35 um CMOS technology and HV CMOS process

  20. Recent progress in high gain InAs avalanche photodiodes (Presentation Recording)

    Bank, Seth; Maddox, Scott J.; Sun, Wenlu; Nair, Hari P.; Campbell, Joe C.

    2015-08-01

    InAs possesses nearly ideal material properties for the fabrication of near- and mid-infrared avalanche photodiodes (APDs), which result in strong electron-initiated impact ionization and negligible hole-initiated impact ionization [1]. Consequently, InAs multiplication regions exhibit several appealing characteristics, including extremely low excess noise factors and bandwidth independent of gain [2], [3]. These properties make InAs APDs attractive for a number of near- and mid-infrared sensing applications including remote gas sensing, light detection and ranging (LIDAR), and both active and passive imaging. Here, we discuss our recent advances in the growth and fabrication of high gain, low noise InAs APDs. Devices yielded room temperature multiplication gains >300, with much reduced (~10x) lower dark current densities. We will also discuss a likely key contributor to our current performance limitations: silicon diffusion into the intrinsic (multiplication) region from the underlying n-type layer during growth. Future work will focus on increasing the intrinsic region thickness, targeting gains >1000. This work was supported by the Army Research Office (W911NF-10-1-0391). [1] A. R. J. Marshall, C. H. Tan, M. J. Steer, and J. P. R. David, "Electron dominated impact ionization and avalanche gain characteristics in InAs photodiodes," Applied Physics Letters, vol. 93, p. 111107, 2008. [2] A. R. J. Marshall, A. Krysa, S. Zhang, A. S. Idris, S. Xie, J. P. R. David, and C. H. Tan, "High gain InAs avalanche photodiodes," in 6th EMRS DTC Technical Conference, Edinburgh, Scotland, UK, 2009. [3] S. J. Maddox, W. Sun, Z. Lu, H. P. Nair, J. C. Campbell, and S. R. Bank, "Enhanced low-noise gain from InAs avalanche photodiodes with reduced dark current and background doping," Applied Physics Letters, vol. 101, no. 15, pp. 151124-151124-3, Oct. 2012.

  1. High gain/broadband oxide glasses for next generation Raman amplifiers

    Rivero, Clara A.

    Interest in Raman amplification has undergone a revival due to the rapidly increasing bandwidth requirements for communications transmission, both for long haul and local area networks, and recent developments in the telecom fiber industry and diode laser technology. In contrast to rare earth doped fiber amplifiers, for which the range of wavelengths is fixed and limited, Raman gain bandwidths are larger and the operating wavelength is fixed only by the pump wavelength and the bandwidth of the Raman active medium. In this context, glasses are the material of choice for this application due to their relatively broad spectral response, and ability of making them into optical fiber. This dissertation summarizes findings on different oxide-based glasses that have been synthesized and characterized for their potential application as Raman gain media. Two main glass families were investigated: phosphate-based glass matrices for broadband Raman gain application and TeO2-based glasses for high Raman gain amplification. A phosphate network was preferred for the broadband application since the phosphate Raman active modes can provide amplification above 1000 cm-1, whilst TeO2-based glasses were selected for the high gain application due to their enhanced nonlinearities and polarizabilities among the other oxide-based network formers. The results summarized in this dissertation show that phosphate-based glasses can provide Raman amplification bandwidths of up to 40 THz, an improvement of almost 5 times the bandwidth of SiO2. On the other hand, tellurite-based glasses appear to be promising candidates for high gain discrete Raman applications, providing peak Raman gain coefficients of up to 50 times higher than SiO 2, at 1064 nm. Although, visible spontaneous Raman scattering cross-section measurement is the most frequently used tool for estimating the strength and spectral distribution of Raman gain in materials, especially glasses, there are some issues that one needs to be

  2. Stability in high gain plasmas in DIII-D

    Fusion power gain has been increased by a factor of 3 in DIII-D plasmas through the use of strong discharge shaping and tailoring of the pressure and current density profiles. H-mode plasmas with weak or negative central magnetic shear are found to have neoclassical ion confinement throughout most of the plasma volume. Improved MHD stability is achieved by controlling the plasma pressure profile width. The highest fusion power gain Q (ratio of fusion power to input power) in deuterium plasmas was 0.0015, which extrapolates to an equivalent Q of 0.32 in a deuterium-tritium plasma and is similar to values achieved in tokamaks of larger size and magnetic fields

  3. Stability in High Gain Plasmas in DIII-D

    Lazarus, E. A.; Hong, R. M. [Oak Ridge National Lab., TN (United States); Navratil, G. A.; Sabbagh, S. [Columbia Univ., New York, NY (United States); Strait, E. J.; Rice, B. W. [Lawrence Livermore National Lab., CA (United States); Ferron, J. R.; Greenfield, C. M.; Austin, M. E. [Maryland Univ., College Park, MD (United States); Chan, V. S.; DeBoo, J. C.; Doyle, E. J. [California Univ., Los Angeles, CA (United States; Durst, R. [Wisconsin Univ., Madison, WI (United States); Forest, C. B. [California Univ., Irvine, CA (United States); Leonard, A. W. [Oak Ridge Associated Universities, Inc., TN (United States); Schissel, D. P. [JET Joint Undertaking, Abingdon (United Kingdom)

    1997-01-01

    Fusion power gain has been increased by a factor of 3 in DIII-D plasmas through the use of strong discharge shaping and tailoring of the pressure and current density profiles. H-mode plasmas with weak or negative central magnetic shear are found to have neoclassical ion confinement throughout most of the plasma volume. Improved MHD stability is achieved by controlling the plasma pressure profile width. The highest fusion power gain Q (ratio of fusion power to input power) in deuterium plasmas was 0.0015. which extrapolates to an equivalent Q of 0.32 in a deuterium-tritium plasma and is similar to values achieved in tokamaks of larger size and magnetic fields.

  4. High Gain and High Directive of Antenna Arrays Utilizing Dielectric Layer on Bismuth Titanate Ceramics

    F. H. Wee

    2012-01-01

    Full Text Available A high gain and high directive microstrip patch array antenna formed from dielectric layer stacked on bismuth titanate (BiT ceramics have been investigated, fabricated, and measured. The antennas are designed and constructed with a combination of two-, four-, and six-BiT elements in an array form application on microwave substrate. For gain and directivity enhancement, a layer of dielectric was stacked on the BiT antenna array. We measured the gain and directivity of BiT array antennas with and without the dielectric layer and found that the gain of BiT array antenna with the dielectric layer was enhanced by about 1.4 dBi of directivity and 1.3 dB of gain over the one without the dielectric layer at 2.3 GHz. The impedance bandwidth of the BiT array antenna both with and without the dielectric layer is about 500 MHz and 350 MHz, respectively, which is suitable for the application of the WiMAX 2.3 GHz system. The utilization of BiT ceramics that covers about 90% of antenna led to high radiation efficiency, and small-size antennas were produced. In order to validate the proposed design, theoretical and measured results are provided and discussed.

  5. SIW HIGH GAIN SLOT ANTENNA FOR WLAN/WIMAX APPLICATION

    Neda Akbari; Javad Nourinia; Ch. Ghobadi

    2014-01-01

    In this paper with using substrate integrated waveguide technology and slot antenna, an antenna array with 8 (2×4) elements has been designed. The antenna substrate is ROGERs 4003 with two different thickness. In lower substrate with 0.5 mm thickness fed network of antenna is putted and upper substrate with 1.5 mm thickness slot in order to radation is embedded. The proposed antenna is designed in C band for WLAN/WiMAX application. Pattern of antenna is directive with peak gain about...

  6. The Gain Properties of 1-D Active Photonic Crystal

    2003-01-01

    The terminology 'ID frequency'(w ID) is proposed after analyzing the 1D active photonic crystal based on the transfer matrix method. The relationship between wID and the structure parameters of the photonic crystal is investigated.

  7. Spontaneous physical activity protects against fat mass gain

    Teske, Jennifer A.; Billington, Charles J.; Kuskowski, Michael A.; Kotz, Catherine M.

    2011-01-01

    It is unclear whether elevated spontaneous physical activity (SPA, very low-intensity physical activity) positively influences body composition long-term. Objective We determined whether SPA and caloric intake were differentially related to the growth curve trajectories of body weight, FM and FFM between obesity resistant and Sprague-Dawley rats at specific age intervals. Design and Subjects Body composition, SPA and caloric intake were measured in selectively-bred obesity resistant and out-b...

  8. SIW HIGH GAIN SLOT ANTENNA FOR WLAN/WIMAX APPLICATION

    Neda Akbari

    2014-01-01

    Full Text Available In this paper with using substrate integrated waveguide technology and slot antenna, an antenna array with 8 (2×4 elements has been designed. The antenna substrate is ROGERs 4003 with two different thickness. In lower substrate with 0.5 mm thickness fed network of antenna is putted and upper substrate with 1.5 mm thickness slot in order to radation is embedded. The proposed antenna is designed in C band for WLAN/WiMAX application. Pattern of antenna is directive with peak gain about 18dBi. In feed netowork is used from new method of feeding with using of aperture couple and cavity resonator method.

  9. Software reconfigurable highly flexible gain switched optical frequency comb source.

    Pascual, M Deseada Gutierrez; Zhou, Rui; Smyth, Frank; Anandarajah, Prince M; Barry, Liam P

    2015-09-01

    The authors present the performance and noise properties of a software reconfigurable, FSR and wavelength tunable gain switched optical frequency comb source. This source, based on the external injection of a temperature tuned Fabry-Pérot laser diode, offers quasi-continuous wavelength tunability over the C-band (30nm) and FSR tunability ranging from 6 to 14GHz. The results achieved demonstrate the excellent spectral quality of the comb tones (RIN ~-130dB/Hz and low phase noise of 300kHz) and its outstanding stability (with fluctuations of the individual comb tones of less than 0.5dB in power and 5pm in wavelength, characterized over 24hours) highlighting its suitability for employment in next generation flexible optical transmission networks. PMID:26368425

  10. Gains of ubiquitylation sites in highly conserved proteins in the human lineage

    Kim Dong Seon

    2012-11-01

    Full Text Available Abstract Background Post-translational modification of lysine residues of specific proteins by ubiquitin modulates the degradation, localization, and activity of these target proteins. Here, we identified gains of ubiquitylation sites in highly conserved regions of human proteins that occurred during human evolution. Results We analyzed human ubiquitylation site data and multiple alignments of orthologous mammalian proteins including those from humans, primates, other placental mammals, opossum, and platypus. In our analysis, we identified 281 ubiquitylation sites in 252 proteins that first appeared along the human lineage during primate evolution: one protein had four novel sites; four proteins had three sites each; 18 proteins had two sites each; and the remaining 229 proteins had one site each. PML, which is involved in neurodevelopment and neurodegeneration, acquired three sites, two of which have been reported to be involved in the degradation of PML. Thirteen human proteins, including ERCC2 (also known as XPD and NBR1, gained human-specific ubiquitylated lysines after the human-chimpanzee divergence. ERCC2 has a Lys/Gln polymorphism, the derived (major allele of which confers enhanced DNA repair capacity and reduced cancer risk compared with the ancestral (minor allele. NBR1 and eight other proteins that are involved in the human autophagy protein interaction network gained a novel ubiquitylation site. Conclusions The gain of novel ubiquitylation sites could be involved in the evolution of protein degradation and other regulatory networks. Although gains of ubiquitylation sites do not necessarily equate to adaptive evolution, they are useful candidates for molecular functional analyses to identify novel advantageous genetic modifications and innovative phenotypes acquired during human evolution.

  11. ASE suppression in high-gain solid-state amplifiers by a leak method

    A leak method was developed to suppress amplified spontaneous emission (ASE) in large-aperture high-gain solid-state amplifiers. The gain medium edges are processed into an arris. The ASE ray will undergo reflection several times at the arris surface when it propagates to the gain medium edges, and most of its power will leak out. This leak method was tested in an experiment, in which a piece of commonly used gain medium was processed for contrast. The maximal increase of the gain value was 5.26% with the maximal pump power. (paper)

  12. ASE suppression in high-gain solid-state amplifiers by a leak method

    Zhang, Yongliang; Ye, Haixian; Li, Mingzhong; Zheng, Jiangang; Wei, Xiaofeng; Gao, Song; Deng, Qinghua; Jiang, Xinying; Yan, Xiongwei; Wang, Zhenguo

    2013-07-01

    A leak method was developed to suppress amplified spontaneous emission (ASE) in large-aperture high-gain solid-state amplifiers. The gain medium edges are processed into an arris. The ASE ray will undergo reflection several times at the arris surface when it propagates to the gain medium edges, and most of its power will leak out. This leak method was tested in an experiment, in which a piece of commonly used gain medium was processed for contrast. The maximal increase of the gain value was 5.26% with the maximal pump power.

  13. High Gain Patch Antenna for 2.4GHz using Metamaterial Superstrate

    Kyu-Chang; LEE; Seung-In; YANG

    2010-01-01

    <正>A patch antenna and our proposed metamaterial patch antenna are simulated and compared. A high gain patch antenna using a single layer metamaterial superstrate with a near to zero refractive index(n)is proposed.The simulation results provide that the gain of the proposed antenna is increased by about 7dB. Consequently,the high gain antenna can be easily obtained by using our metamaterial superstrate.

  14. 20 CFR 220.29 - Work that is considered substantial gainful activity.

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Work that is considered substantial gainful... RAILROAD RETIREMENT ACT DETERMINING DISABILITY Disability Under the Railroad Retirement Act for Any Regular Employment § 220.29 Work that is considered substantial gainful activity. Work is considered to...

  15. High school athletes and athletic leaders gain higher test scores

    Yeung, Ryan

    2015-01-01

    Does participating in high school athletics programs help or hinder students from getting good grades? In new research, Ryan Yeung finds a link between academic achievement and athletic participation in high school. Using data from a study begun in 1980, he finds that those students who were athletes or athletic leaders had grades between 8 and 13 percent higher than those that were non-athletes. He argues that the skills developed as a participant or leader on an athletic team...

  16. A kind of micro-FEL device with super-high gain

    In this paper the author has studied the gain characteristic of a FEL and found that there is a kind of micro-FEL device with super-high gain. This FEL device lies on the far infrared spectrum, it consists of a rf-linac and the electron beam of high brightness, a microwiggler and a capillary waveguide

  17. High gain durable anti-reflective coating with oblate voids

    Maghsoodi, Sina; Brophy, Brenor L.; Colson, Thomas E.; Gonsalves, Peter R.; Abrams, Ze' ev

    2016-06-28

    Disclosed herein are single layer transparent coatings with an anti-reflective property, a hydrophobic property, and that are highly abrasion resistant. The single layer transparent coatings contain a plurality of oblate voids. At least 1% of the oblate voids are open to a surface of the single layer transparent coatings.

  18. HGTF - laser facility for high thermonuclear target gain investigations

    George, E.V.; Kuzubov, A.S.; Storm, E. [Lawrence Livermore National Lab., CA (United States); Il`kaev, R.I.; Kirillov, G.A.; Kochemasov, G.G.; Kulikov, S.M.; Pevny, S.N.; Ryabev, L.D.; Sukharev, S.A.

    1995-05-01

    This document deals with laser thermonuclear fusion and the demonstration of self-sustained DT fuel thermonuclear burning. It presents experimental results obtained at VNIIEF on iodine lasers and a concept of a high-power laser facility producing 10 MJ shown at VNIIEF and LLNL, using explosive pump sources, a multi-sectional SBS mirror and multi-pass frequency converters. (TEC). 7 refs., 11 figs.

  19. Heavily Tm3+-Doped Silicate Fiber for High-Gain Fiber Amplifiers

    Yin-Wen Lee; Han-Wei Chien; Che-Hung Cho; Ju-Zhe Chen; Juin-Shin Chang; Shibin Jiang

    2013-01-01

    We report on investigation the potential of a 7 wt% (8.35 × 1020 Tm3+/cm3) doped silicate fibers for high-gain fiber amplifiers. Such a high ion concentration significantly reduces the required fiber length of high-power 2 μm fiber laser systems and allows the high-repetition rate operation in 2 μm mode-locked fiber lasers. To evaluate the feasibility of extracting high gain-per-unit-length from this gain medium, we measure several key material properties of the silicate fiber, including the ...

  20. High energy gain electron beam acceleration by 100TW laser

    A laser wakefield acceleration experiment using a 100TW laser is planed at JAERI-Kansai. High quality and short pulse electron beams are necessary to accelerate the electron beam by the laser. Electron beam - laser synchronization is also necessary. A microtron with a photocathode rf-gun was prepared as a high quality electron injector. The quantum efficiency (QE) of the photocathode of 2x10-5 was obtained. A charge of 100pC from the microtron was measured. The emittance and pulse width of the electron beam was 6π mm-mrad and 10ps, respectively. In order to produce a short pulse electron beam, and to synchronize between the electron beam and the laser pulse, an inverse free electron laser (IFEL) is planned. One of problems of LWFA is the short acceleration length. In order to overcome the problem, a Z-pinch plasma waveguide will be prepared as a laser wakefield acceleration tube for 1 GeV acceleration. (author)

  1. Effects of high CO2 levels on dynamic photosynthesis: carbon gain, mechanisms, and environmental interactions.

    Tomimatsu, Hajime; Tang, Yanhong

    2016-05-01

    Understanding the photosynthetic responses of terrestrial plants to environments with high levels of CO2 is essential to address the ecological effects of elevated atmospheric CO2. Most photosynthetic models used for global carbon issues are based on steady-state photosynthesis, whereby photosynthesis is measured under constant environmental conditions; however, terrestrial plant photosynthesis under natural conditions is highly dynamic, and photosynthetic rates change in response to rapid changes in environmental factors. To predict future contributions of photosynthesis to the global carbon cycle, it is necessary to understand the dynamic nature of photosynthesis in relation to high CO2 levels. In this review, we summarize the current body of knowledge on the photosynthetic response to changes in light intensity under experimentally elevated CO2 conditions. We found that short-term exposure to high CO2 enhances photosynthetic rate, reduces photosynthetic induction time, and reduces post-illumination CO2 burst, resulting in increased leaf carbon gain during dynamic photosynthesis. However, long-term exposure to high CO2 during plant growth has varying effects on dynamic photosynthesis. High levels of CO2 increase the carbon gain in photosynthetic induction in some species, but have no significant effects in other species. Some studies have shown that high CO2 levels reduce the biochemical limitation on RuBP regeneration and Rubisco activation during photosynthetic induction, whereas the effects of high levels of CO2 on stomatal conductance differ among species. Few studies have examined the influence of environmental factors on effects of high levels of CO2 on dynamic photosynthesis. We identified several knowledge gaps that should be addressed to aid future predictions of photosynthesis in high-CO2 environments. PMID:27094437

  2. Avalanche effect and gain saturation in high harmonic generation

    Serrat, Carles; Budesca, Josep M; Seres, Jozsef; Seres, Enikoe; Aurand, Bastian; Hoffmann, Andreas; Namba, Shinichi; Kuehl, Thomas; Spielmann, Christian

    2015-01-01

    Optical amplifiers in all ranges of the electromagnetic spectrum exhibit two essential characteristics: i) the input signal during the propagation in the medium is multiplied by the avalanche effect of the stimulated emission to produce exponential growth and ii) the amplification saturates at increasing input signal. We demonstrate that the strong-field theory in the frame of high harmonic generation fully supports the appearance of both the avalanche and saturation effects in the amplification of extreme ultraviolet attosecond pulse trains. We confirm that the amplification takes place only if the seed pulses are perfectly synchronized with the driving strong field in the amplifier. We performed an experimental study and subsequent model calculation on He gas driven by intense 30-fs-long laser pulses, which was seeded with an attosecond pulse train at 110 eV generated in a separated Ne gas jet. The comparison of the performed calculations with the measurements clearly demonstrates that the pumped He gas med...

  3. High gain and high spatial resolution optical parametric amplification imaging under continuous-wave laser irradiation

    This paper presents a novel design for non-collinear optical parametric amplification imaging where an intense ultrashort light pulse chain is used to pump and thereby amplify a continuous-wave (CW) illuminating laser. The setup needs no temporal synchronization between the pump and the CW signal, so it is simple and compact. This design allows us to realize optical imaging for different spectral demands by flexibly changing the CW (tunable) illuminating laser sources, meanwhile with high gain and broad spatial bandwidth, by using an ultrashort pulse laser system as pump. Experimentally, a wavelength-shifted image is achieved with optical gain up to 106 and a two-dimensional space-bandwidth product of more than 20 000 based on this design. (paper)

  4. High speed (<= 250 ps) high gain X-ray shutter camera

    A high speed X-ray shutter tube has been developed for laser induced plasma imaging. The limiting exposure time is in the 250 ps range and 5 images can be recorded on the same, laser shot, in order to provide a 5 spectral channel analysis of the plasma. A high light gain is obtained from a microchannel plate inserted in the 50Ω transmission line, which provide the adapted structure to reach such a time exposure. We present the main performances of this camera

  5. The Design of High-Q Sallen-Key Biquads with Unity-Gain Buffer Amplifiers

    Gaunholt, Hans; Guldbrandsen, Birthe

    1997-01-01

    and to implement the Sallen- Key biquad even in the high-Q case with reasonable sensitivities. The method is based on the unity gain version of the biquad and as unity gain buffer amplifiers are readily manufactured in integrated circuit technology the results may be very useful in the fabrication of integrated...

  6. Whey protein reduces early life weight gain in mice fed a high-fat diet

    Tranberg, Britt; Hellgren, Lars; Lykkesfeldt, Jens;

    2013-01-01

    reduced weight gain in young C57BL/6 mice fed a high-fat diet compared to casein. Although the effect on weight gain ceased, whey alleviated glucose intolerance, improved insulin sensitivity and reduced plasma cholesterol. These findings could not be explained by changes in food intake or gut microbiota...

  7. Muscle activity during functional coordination training: implications for strength gain and rehabilitation

    Jørgensen, Marie Birk; Andersen, Lars Louis; Kirk, Niels;

    2010-01-01

    The purpose of this study was to evaluate if different types, body positions, and levels of progression of functional coordination exercises can provide sufficiently high levels of muscle activity to improve strength of the neck, shoulder, and trunk muscles. Nine untrained women were familiarized...... coordination training can be performed with a muscle activity sufficient for strength gain. Functional coordination training may therefore be a good choice for prevention or rehabilitation of musculoskeletal pain or injury in the neck, shoulder, or trunk muscles.......The purpose of this study was to evaluate if different types, body positions, and levels of progression of functional coordination exercises can provide sufficiently high levels of muscle activity to improve strength of the neck, shoulder, and trunk muscles. Nine untrained women were familiarized...... with 7 functional coordination exercises 12 times during 4 weeks before testing. Surface electromyographic (EMG) activity was obtained from rectus abdominus, erector spinae, obliquus externus, and trapezius during the exercises with 2-4 levels of progression. Electromyography was normalized to the...

  8. Angular spectrum characters of high gain non-critical phase match optical parametric oscillators

    Liu Jian-Hui; Liu Qiang; Gong Ma-Li

    2011-01-01

    The angular spectrum gain characters and the power magnification characters of high gain non-walk-off colinear optical parametric oscillators have been studied using the non-colinear phase match method for the first time. The experimental results of the KTiOAsO4 and the KTiOPO4 crystals are discussed in detail. At the high energy single resonant condition, low reflective ratio of the output mirror for the signal and long non-linear crystal are beneficial for small divergence angles. This method can also be used for other high gain non-walk-off phase match optical parametric processes.

  9. Low-noise pseudomorphic dual-gate cascode HEMT's with extremely high gain

    Wenger, J.; Narozny, P.; Daembkes, H.; Splettstoesser, J.; Werres, C.

    1992-02-01

    Quarter-micron InGaAs-GaAs dual-gate HEMTs connected as a cascode MMIC in a compact manner have been fabricated and investigated. The devices show a high output impedance and a very low feedback capacitance, resulting in a high-voltage gain factor gm/gd of 125 and a Cgs/Cgd ratio of 45. The current gain cutoff frequency fT is 45 GHz and the maximum stable gain is 23.5 dB at 10 GHz and 19 dB at 20 GHz. The pseudomorphic cascode HEMTs show a low-noise figure of 1.1 dB with an associated gain of 22 dB at 10 GHz, at 18 GHz the minimum noise figure is 1.9 dB with 16-dB gain.

  10. Operation regimes, gain dynamics and highly stable operation points of Ho:YLF regenerative amplifiers

    Kroetz, Peter; Calendron, Anne-Laure; Chatterjee, Gourab; Cankaya, Huseyin; Murari, Krishna; Kaertner, Franz X; Hartl, Ingmar; Miller, R J Dwayne

    2016-01-01

    We present a comprehensive study of laser pulse amplification with respect to operation regimes, gain dynamics, and highly stable operation points of Ho:YLF regenerative amplifiers (RAs). The findings are expected to be more generic than for this specific case. Operation regimes are distinguished with respect to pulse energy and the appearance of pulse instability as a function of the repetition rate, seed energy, and pump intensity. The corresponding gain dynamics are presented, identifying highly stable operation points related to high gain build -up during pumping and high gain depletion during pulse amplification. These operation points are studied numerically and experimentally as a function of several parameters, thereby achieving, for our Ho:YLF RA, highly stable output pulses with measured fluctuations of only 0.19% (standard deviation).

  11. Phase and gain control policies for robust active vibration control of flexible structures

    Zhang, Kai; Scorletti, Gérard; Ichchou, Mohamed; Mieyeville, F.

    2013-01-01

    The interest of this paper is to develop a general and systematic robust control methodology for active vibration control of flexible structures. For this purpose, first phase and gain control policies are proposed to impose qualitative frequency-dependent requirements on the controller to consider a complete set of control objectives. Then the proposed control methodology is developed by employing phase and gain control policies in the dynamic output feedback H∞ control: according to the set...

  12. Role of nonexercise activity thermogenesis in resistance to fat gain in humans.

    Levine, J A; Eberhardt, N L; Jensen, M D

    1999-01-01

    Humans show considerable interindividual variation in susceptibility to weight gain in response to overeating. The physiological basis of this variation was investigated by measuring changes in energy storage and expenditure in 16 nonobese volunteers who were fed 1000 kilocalories per day in excess of weight-maintenance requirements for 8 weeks. Two-thirds of the increases in total daily energy expenditure was due to increased nonexercise activity thermogenesis (NEAT), which is associated with fidgeting, maintenance of posture, and other physical activities of daily life. Changes in NEAT accounted for the 10-fold differences in fat storage that occurred and directly predicted resistance to fat gain with overfeeding (correlation coefficient = 0.77, probability activation of NEAT dissipates excess energy to preserve leanness and that failure to activate NEAT may result in ready fat gain. PMID:9880251

  13. Very High Gain and Low Noise Near Infrared Single Photon Counting Detectors and Arrays Project

    National Aeronautics and Space Administration — Amplification Technologies Inc ("ATI") proposes to develop the enabling material and device technology for the design of ultra low noise, high gain and low...

  14. Brightness and coherence of synchrotron radiation and high-gain free electron lasers

    The characteristics of synchrotron radiation are reviewed with particular attention to its phase-space properties and coherence. The transition of the simple undulator radiation to more intense, more coherent high-gain free electron lasers, is discussed

  15. Investigation of the avalanche photodiodes for the CMS electromagnetic calorimeter operated at high gain

    Deiters, K; Godinovic, N; Ingram, Q; Longo, E; Montecchi, M; Musienko, Yu V; Nicol, S; Patel, B; Renker, D; Reucroft, S; Rusack, R W; Sakhelashvili, T M; Singovsky, A V; Soric, I; Swain, J D; Vikas, P

    2001-01-01

    Avalanche photodiodes (APD) with improved characteristics were developed by Hamamatsu Photonics for the electromagnetic calorimeter of the CMS experiment. This report presents measurements of the latest generation of APDs, which are capable to operate at high gains (~2000). (5 refs).

  16. Gain media edge treatment to suppress amplified spontaneous emission in a high power laser

    Hackel, Lloyd A.; Soules, Thomas F.; Fochs, Scott N.; Rotter, Mark D.; Letts, Stephan A.

    2008-12-09

    A novel method and apparatus for suppressing ASE and parasitic oscillation modes in a high average power laser is introduced. By roughening one or more peripheral edges of a solid-state crystal or ceramic laser gain media and by bonding such edges using a substantially high index bonding elastomer or epoxy to a predetermined electromagnetic absorbing arranged adjacent to the entire outer surface of the peripheral edges of the roughened laser gain media, ASE and parasitic oscillation modes can be effectively suppressed.

  17. Brightness and coherence of radiation from undulators and high-gain free electron lasers

    The purpose of this paper is to review the radiation characteristics of undulators and high-gain free electron lasers (FELs). The topics covered are: a phase-space method in wave optics and synchrotron radiation, coherence from the phase-space point of view, discussions of undulator performances in next-generation synchrotron radiation facility and the characteristics of the high-gain FELs and their performances

  18. Gain stabilization of scintillation and Cerenkov spectrometers at high counting rates

    A photomultiplier gain stabilization system, capable of operation at rates well over 5x104 pulses/s, is described. Pile-up and dead-time effects, which hamper conventional systems at such rates, are minimized through the use of a fast-gated charge sensitive integrator directly coupled to the photomultiplier anode. Deviations in the time-averaged response to a reference light pulser are fed back to control the high-voltage supply. Rapid fluctuations due to variations in average dynode current are reduced through the use of active voltage divider chains. Stability, tested with a large NaI(Tl) crystal viewed by five photomultiplier tubes, is better than 0.7% over 24 h, and for counting rates changing from a few hundred counts/s to over 2x105 counts/s. (Auth.)

  19. Modeling of gain saturation effects in active semiconductor photonic crystal waveguides

    Chen, Yaohui; Mørk, Jesper

    2012-01-01

    In this paper, we present a theoretical analysis of slow-light enhanced light amplification in an active semiconductor photonic crystal line defect waveguide. The impact of enhanced light-matter interactions on carrier-depletion-induced modal gain saturation is investigated.......In this paper, we present a theoretical analysis of slow-light enhanced light amplification in an active semiconductor photonic crystal line defect waveguide. The impact of enhanced light-matter interactions on carrier-depletion-induced modal gain saturation is investigated....

  20. Loop gain stabilizing with an all-digital automatic-gain-control method for high-precision fiber-optic gyroscope.

    Zheng, Yue; Zhang, Chunxi; Li, Lijing; Song, Lailiang; Chen, Wen

    2016-06-10

    For a fiber-optic gyroscope (FOG) using electronic dithers to suppress the dead zone, without a fixed loop gain, the deterministic compensation for the dither signals in the control loop of the FOG cannot remain accurate, resulting in the dither residuals in the FOG rotation rate output and the navigation errors in the inertial navigation system. An all-digital automatic-gain-control method for stabilizing the loop gain of the FOG is proposed. By using a perturbation square wave to measure the loop gain of the FOG and adding an automatic gain control loop in the conventional control loop of the FOG, we successfully obtain the actual loop gain and make the loop gain converge to the reference value. The experimental results show that in the case of 20% variation in the loop gain, the dither residuals are successfully eliminated and the standard deviation of the FOG sampling outputs is decreased from 2.00  deg/h to 0.62  deg/h (sampling period 2.5 ms, 10 points smoothing). With this method, the loop gain of the FOG can be stabilized over the operation temperature range and in the long-time application, which provides a solid foundation for the engineering applications of the high-precision FOG. PMID:27409016

  1. Performance studies of high gain photomultiplier having Z-configuration of microchannel plates

    Lo, C. C.; Leskovar, B.

    1980-11-01

    The characteristics of a high gain type ITT F4129 photomultiplier having three microchannel plates in cascade for electron multiplications were investigated. These plates are in the Z-configuration. Measurements are given of the gain dark current, cathode quantum efficiency, anode pulse linearity, electron transit time, single and multiphoton time spreads, fatigue, and pulse height resolution. The gain as a function of transverse magnetic field was measured and discussed. Photomultiplier characteristics as a function of the input pulse repetition frequency were also investigated and discussed.

  2. Calculation of the gain coefficient in cryogenically cooled Yb : YAG disks at high heat generation rates

    Vadimova, O L; Mukhin, I B; Kuznetsov, I I; Palashov, O V; Perevezentsev, E A; Khazanov, Efim A [Institute of Applied Physics, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

    2013-03-31

    We have calculated the stored energy and gain coefficient in disk gain elements cooled to cryogenic temperatures. The problem has been solved with allowance for intense heat generation, amplified spontaneous emission and parasitic lasing, without averaging over any spatial coordinate. The numerical simulation results agree well with experimental data, in particular at high heat generation rates. Experimental data and theoretical analysis indicate that composite disk gain elements containing an undoped region can store considerably more energy due to suppression of amplified spontaneous emission and parasitic lasing. (extreme light fields and their applications)

  3. Calculation of the gain coefficient in cryogenically cooled Yb : YAG disks at high heat generation rates

    We have calculated the stored energy and gain coefficient in disk gain elements cooled to cryogenic temperatures. The problem has been solved with allowance for intense heat generation, amplified spontaneous emission and parasitic lasing, without averaging over any spatial coordinate. The numerical simulation results agree well with experimental data, in particular at high heat generation rates. Experimental data and theoretical analysis indicate that composite disk gain elements containing an undoped region can store considerably more energy due to suppression of amplified spontaneous emission and parasitic lasing. (extreme light fields and their applications)

  4. Shock ignition: a new approach to high gain inertial confinement fusion on the national ignition facility.

    Perkins, L J; Betti, R; LaFortune, K N; Williams, W H

    2009-07-24

    Shock ignition, an alternative concept for igniting thermonuclear fuel, is explored as a new approach to high gain, inertial confinement fusion targets for the National Ignition Facility (NIF). Results indicate thermonuclear yields of approximately 120-250 MJ may be possible with laser drive energies of 1-1.6 MJ, while gains of approximately 50 may still be achievable at only approximately 0.2 MJ drive energy. The scaling of NIF energy gain with laser energy is found to be G approximately 126E (MJ);{0.510}. This offers the potential for high-gain targets that may lead to smaller, more economic fusion power reactors and a cheaper fusion energy development path. PMID:19659364

  5. Utilizing wideband AMC structures for high-gain inkjet-printed antennas on lossy paper substrate

    Cook, Benjamin Stassen

    2013-01-01

    Significant gain and bandwidth improvement of inkjet-printed antennas with integrated artificial magnetic conductor (AMC) is achieved by utilizing wideband ground-backed frequency selective surfaces (FSSs) to overcome the high losses of organic substrates such as paper. A microstrip-fed monopole mounted on an artificial magnetic conductor is demonstrated to improve the gain by 5 dB over previous works and exhibit much wider impedance bandwidth while maintaining a thin antenna profile and a 20% electrical size reduction. The effect of AMC bandwidth on substrate losses and the gain reduction caused by finite AMC array effects are investigated in an effort to produce high-gain, miniaturized, low-cost wearable and structure mount antennas. © 2013 IEEE.

  6. 3-D numerical analysis of a high-gain free-electron laser

    We present a novel approach to the 3-dimensional high-gain free- electron laser amplifier problem. The method allows us to write the laser field as an integral equation which can be efficiently and accurately evaluated on a small computer. The model is general enough to allow the inclusion of various initial electron beam distributions to study the gain reduction mechanism and its dependence on the physical parameters. 16 refs., 8 figs., 1 tab

  7. Entanglement, EPR correlations and mesoscopic quantum superposition by the high-gain quantum injected parametric amplification

    Caminati, Marco; De Martini, Francesco; Perris, Riccardo; Sciarrino, Fabio; Secondi, Veronica

    2006-01-01

    We investigate the multiparticle quantum superposition and the persistence of multipartite entanglement of the quantum superposition generated by the quantum injected high-gain optical parametric amplification of a single photon. The physical configuration based on the optimal universal quantum cloning has been adopted to investigate how the entanglement and the quantum coherence of the system persists for large values of the nonlinear parametric gain g.

  8. High performance quantum cascade lasers: Loss, beam stability, and gain engineering

    Bouzi, Pierre Michel

    Quantum Cascade (QC) lasers are semiconductor devices emitting in the mid-infrared (3-30 micron) and terahertz (30-300 micron) regions of the electromagnetic spectrum. Since their first demonstration by Jerome Faist et. al. in 1994, they have evolved very quickly into high performance devices and given rise to many applications such as trace-gas sensing, medical diagnosis, free-space communication, and light detection and ranging (LIDAR). In this thesis, we investigate a further increase of the performance of QC devices and, through meticulous device modeling and characterizations, gain a deeper understanding of several of their unique characteristics, especially their carrier transport and lifetime, their characteristic temperature, their waveguide loss and modal gain, their leakage current, and their transverse mode profile. First, in our quest to achieve higher performance, we investigate the effect of growth asymmetries on device transport characteristics. This investigation stems from recent studies on the role of interface roughness on intersubband scattering and device performance. Through a symmetric active core design, we find that interface roughness and ionized impurity scattering induced by dopant migration play a significant role in carrier transport through the device. Understanding how interface roughness affects intersubband scattering, in turn, we engineer the gain in QC devices by placing monolayer barriers at specific locations within the device band structure. These strategically placed additional thin barrier layers introduce roughness scattering into the device active region, thereby selectively decreasing the lower laser state lifetime and increasing population inversion necessary for laser action. Preliminary measurement results from modified devices reveal a 50% decrease in the emission broadening compared to the control structures, which should lead to a two-fold increase in gain. A special class of so-called "strong coupling" QC lasers

  9. Graphene/GaSe-Nanosheet Hybrid: Towards High Gain and Fast Photoresponse

    Lu, Rongtao; Liu, Jianwei; Luo, Hongfu; Chikan, Viktor; Wu, Judy Z.

    2016-01-01

    While high photoconductive gain has been recently achieved in graphene-based hybrid phototransistors using semiconductor two-dimensional transition/post-transition metal dichalcogenides or quantum dots sensitizers, obtaining fast photoresponse simutaneously remains a challenge that must be addressed for practical applications. In this paper we report a graphene/GaSe nanosheets hybrid photodetector, in which GaSe nanosheets provide a favorable geometric link to graphene conductive layer through van Der Waals force. After a vacuum annealing process, a high gain in exceeding 107 has been obtained simitaneously with a dynamic response time of around 10 ms for both light on and off. We attribute the high performance to the elimination of possible deep charge traps, most probably at the graphene/GaSe nanosheets interface. This result demonstrates high photoconductive gain and fast photoresponse can be achieved simultaneously and a clean interface is the key to the high performance of these hybrid devices.

  10. Achievement of public health recommendations for physical activity and prevention of gains in adiposity in adults

    Grøntved, A.

    2013-01-01

    Physical activity (PA) is considered a cornerstone in weight control and public health guidelines recommend regular participation to prevent gains in adiposity. It may therefore come as a surprise that the cumulative evidence from observational studies to support this is not strong. A weakness of...

  11. Enhanced optical precursors by Doppler effect via active Raman gain process.

    Peng, Yandong; Niu, Yueping; Zhang, Lida; Yang, Aihong; Jiang, Lin; Gong, Shangqing

    2012-08-15

    A scheme for enhancing precursor pulse by Doppler effect is proposed in a room-temperature active-Raman-gain medium. Due to abnormal dispersion between two gain peaks, main fields are advanced and constructively interfere with optical precursors, which leads to enhancement of the transient pulse at the rise edge of the input. Moreover, after Doppler averaging, the abnormal dispersion intensifies and the constructive interference between precursors and main fields is much strengthened, which boosts the transient spike. Simulation results demonstrate that the peak intensity of precursors could be enhanced nearly 20 times larger than that of the input. PMID:23381248

  12. Angular spectrum characters of high gain non-critical phase match optical parametric oscillators

    The angular spectrum gain characters and the power magnification characters of high gain non-walk-off colinear optical parametric oscillators have been studied using the non-colinear phase match method for the first time. The experimental results of the KTiOAsO4 and the KTiOPO4 crystals are discussed in detail. At the high energy single resonant condition, low reflective ratio of the output mirror for the signal and long non-linear crystal are beneficial for small divergence angles. This method can also be used for other high gain non-walk-off phase match optical parametric processes. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  13. Development of low read noise high conversion gain CMOS image sensor for photon counting level imaging

    Seo, Min-Woong; Kawahito, Shoji; Kagawa, Keiichiro; Yasutomi, Keita

    2016-05-01

    A CMOS image sensor with deep sub-electron read noise and high pixel conversion gain has been developed. Its performance is recognized through image outputs from an area image sensor, confirming the capability of photoelectroncounting- level imaging. To achieve high conversion gain, the proposed pixel has special structures to reduce the parasitic capacitances around FD node. As a result, the pixel conversion gain is increased due to the optimized FD node capacitance, and the noise performance is also improved by removing two noise sources from power supply. For the first time, high contrast images from the reset-gate-less CMOS image sensor, with less than 0.3e- rms noise level, have been generated at an extremely low light level of a few electrons per pixel. In addition, the photon-counting capability of the developed CMOS imager is demonstrated by a measurement, photoelectron-counting histogram (PCH).

  14. Gain optimization in fiber optical parametric amplifiers by combining standard and high-SBS threshold highly nonlinear fibers

    Da Ros, Francesco; Rottwitt, Karsten; Peucheret, Christophe

    2012-01-01

    Combining Al-doped and Ge-doped HNLFs as gain media in FOPAs is proposed and optimized, resulting in efficient SBS mitigation while circumventing the additional loss of the high SBS threshold Al-doped fiber.......Combining Al-doped and Ge-doped HNLFs as gain media in FOPAs is proposed and optimized, resulting in efficient SBS mitigation while circumventing the additional loss of the high SBS threshold Al-doped fiber....

  15. Multi-Level DC-DC Converter for High Gain Applications

    Girish Ganesan R

    2013-12-01

    Full Text Available The output voltage from most renewable energy sources like photovoltaic arrays and fuel cells will be at low level. This must be stepped up considerably for practical utilization or grid connection. The presented multilevel boost converter DC-DC converter topology consists of the conventional boost converter and voltage doubler stages to provide high voltage gain. The proposed topology uses only one switch along with one inductor, (2N-1 diodes and (2N-1 capacitors for obtaining an output which is N times the conventional boost converter. In this topology, each device blocks only one voltage level. The main advantages of this topology are continuous input current, large gain without high duty cycle or transformer, modularity and use of devices with low voltage ratings. Experimental results obtained from the 100W prototype demonstrate the voltage gain capability of the converter and validates the converter design.

  16. Inkjet Printing of Paper-Based Wideband and High Gain Antennas

    Cook, Benjamin

    2011-12-07

    This thesis represents a major contribution to wideband and high gain inkjet-printed antennas on paper. This work includes the complete characterization of the inkjet printing process for passive microwave devices on paper substrate as well as several ultra-wideband and high gain antenna designs. The characterization work includes the electrical characterization of the permittivity and loss tangent for paper substrate through 10 GHz, ink conductivity data for variable sintering conditions, and minimum feature sizes obtainable by today’s current inkjet processes for metallic nanoparticles. For the first time ever, inkjet-printed antennas are demonstrated that operate over the entire UWB band and demonstrate gains up to 8dB. This work also presents the first fractal-based inkjet-printed antennas with enhanced bandwidth and reduced production costs, and a novel slow wave log periodic dipole array which shows minimizations of 20% in width over conventional log periodic antennas.

  17. Improvement on a 2 × 2 Elements High-Gain Circularly Polarized Antenna Array

    C. Liu

    2015-01-01

    Full Text Available A novel antipodal Vivaldi antenna with tapering serrated structure at the edges is proposed. Compared with traditional Vivaldi antennas without serrated structure, the gain of the designed antenna is significantly improved in the desired frequency band (4.5–7.5 GHz. In addition, a 2 × 2 Vivaldi antenna array with an orthorhombic structure is designed and fabricated to achieve a circular polarization (CP characteristic. With this configuration, the 3 dB axial ratio bandwidth of the array reaches about 42% with respect to the center frequency of 6 GHz and a high gain is achieved as well. The novel Vivaldi antenna and CP antenna array both have ultrawide band (UWB and high-gain characteristics, which may be applied to the field of commercial communication, remote sensing, and so forth.

  18. Comparative analysis of the intrinsic voltage gain and unit gain frequency between SOI and bulk FinFETs up to high temperatures

    Oliveira, Alberto Vinicius de; Agopian, Paula Ghedini Der; Martino, Joao Antonio; Simoen, Eddy; Claeys, Cor; Collaert, Nadine; Thean, Aaron

    2016-09-01

    This paper presents an experimental analysis of the analog application figures of merit: the intrinsic voltage gain (AV) and unit gain frequency, focusing on the performance comparison between silicon triple gate pFinFET devices, which were processed on both Si and Silicon-On-Insulator (SOI) substrates. The high temperature (from 25 °C to 150 °C) influence and different channel lengths and fin widths were also taken into account. While the temperature impact on the intrinsic voltage gain (AV) is limited, the unit gain frequency was strongly affected due to the carrier mobility degradation at higher temperatures, for both p- and n-type FinFET structures. In addition, the pFinFETs showed slightly larger AV values compared to the n-type counterparts, whereby the bulk FinFETs presented a higher dispersion than the SOI FinFETs.

  19. Ultra-high gain in an Yb3+-doped dielectric waveguide

    Geskus, D.; Aravazhi, S.; Garcia Blanco, S.M.; Pollnau, M.

    2011-01-01

    Thanks to high dopant concentration, large transition cross-sections, and strong light confinement, modal gain of ~1000 dB/cm, comparable to semiconductor optical amplifiers, is demonstrated in a large-refractive-index-contrast KGd0.535Yb0.475(WO4)2 channel waveguide on a KY(WO4)2 substrate.

  20. Quantum limited noise figure operation of high gain erbium doped fiber amplifiers

    Lumholt, Ole; Povlsen, Jørn Hedegaard; Schüsler, Kim;

    1993-01-01

    Performance improvements obtained by using an isolator as an amplified-spontaneous-emission-suppressing component within erbium-doped fibers are evaluated. Simultaneous high-gain and near-quantum-limited noise figures can be obtained by such a scheme. The noise figure improves for input signal po...

  1. Magnetically coupled high-gain Y-source isolated DC/DC converter

    Siwakoti, Yam P.; Loh, Poh Chiang; Blaabjerg, Frede;

    2014-01-01

    A new form of magnetically coupled DC/DC converter is proposed for medium power applications (250 W to 2 kW), requiring a high-voltage gain, short inductive charging time and galvanic isolation. The proposed converter can be realised using a unique Y-source impedance network and a two-switch push...

  2. High-Current Gain Two-Dimensional MoS₂-Base Hot-Electron Transistors.

    Torres, Carlos M; Lan, Yann-Wen; Zeng, Caifu; Chen, Jyun-Hong; Kou, Xufeng; Navabi, Aryan; Tang, Jianshi; Montazeri, Mohammad; Adleman, James R; Lerner, Mitchell B; Zhong, Yuan-Liang; Li, Lain-Jong; Chen, Chii-Dong; Wang, Kang L

    2015-12-01

    The vertical transport of nonequilibrium charge carriers through semiconductor heterostructures has led to milestones in electronics with the development of the hot-electron transistor. Recently, significant advances have been made with atomically sharp heterostructures implementing various two-dimensional materials. Although graphene-base hot-electron transistors show great promise for electronic switching at high frequencies, they are limited by their low current gain. Here we show that, by choosing MoS2 and HfO2 for the filter barrier interface and using a noncrystalline semiconductor such as ITO for the collector, we can achieve an unprecedentedly high-current gain (α ∼ 0.95) in our hot-electron transistors operating at room temperature. Furthermore, the current gain can be tuned over 2 orders of magnitude with the collector-base voltage albeit this feature currently presents a drawback in the transistor performance metrics such as poor output resistance and poor intrinsic voltage gain. We anticipate our transistors will pave the way toward the realization of novel flexible 2D material-based high-density, low-energy, and high-frequency hot-carrier electronic applications. PMID:26524388

  3. INSIGHTS GAINED AS A RESULT OF A HIGH SCHOOL SOCIAL STUDIES COURSE.

    LALOR, IDA B.

    A STUDY ATTEMPTED TO DETERMINE WHETHER HIGH SCHOOL STUDENTS WHO HAVE GAINED KNOWLEDGE AND UNDERSTANDING OF CONCEPTS IN ANTHROPOLOGY WOULD--(1) ACHIEVE GREATER SELF-INSIGHT, (2) BECOME LESS ETHNOCENTRIC IN THEIR ATTITUDES TOWARD OTHERS, AND (3) INCREASE THEIR ABILITY TO THINK CRITICALLY ABOUT SOCIAL PROBLEMS. A 1-YEAR EXPERIMENTAL COURSE ON WORLD…

  4. High-Current Gain Two-Dimensional MoS 2 -Base Hot-Electron Transistors

    Torres, Carlos M.

    2015-12-09

    The vertical transport of nonequilibrium charge carriers through semiconductor heterostructures has led to milestones in electronics with the development of the hot-electron transistor. Recently, significant advances have been made with atomically sharp heterostructures implementing various two-dimensional materials. Although graphene-base hot-electron transistors show great promise for electronic switching at high frequencies, they are limited by their low current gain. Here we show that, by choosing MoS2 and HfO2 for the filter barrier interface and using a noncrystalline semiconductor such as ITO for the collector, we can achieve an unprecedentedly high-current gain (α ∼ 0.95) in our hot-electron transistors operating at room temperature. Furthermore, the current gain can be tuned over 2 orders of magnitude with the collector-base voltage albeit this feature currently presents a drawback in the transistor performance metrics such as poor output resistance and poor intrinsic voltage gain. We anticipate our transistors will pave the way toward the realization of novel flexible 2D material-based high-density, low-energy, and high-frequency hot-carrier electronic applications. © 2015 American Chemical Society.

  5. 75 FR 61228 - Board Meeting: Technical Lessons Gained From High-Level Nuclear Waste Disposal Efforts

    2010-10-04

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR WASTE TECHNICAL REVIEW BOARD Board Meeting: Technical Lessons Gained From High-Level Nuclear Waste Disposal Efforts Pursuant to its authority under section 5051 of Public Law 100-203, Nuclear Waste Policy Amendments Act...

  6. High-precision gas gain and energy transfer measurements in Ar–CO2 mixtures

    Ar–CO2 is a Penning mixture since a fraction of the energy stored in Ar 3p53d and higher excited states can be transferred to ionize CO2 molecules. In the present work, concentration and pressure dependence of Penning transfer rate and photon feedback parameter in Ar–CO2 mixtures have been investigated with recent systematic high-precision gas gain measurements which cover the range 1–50% CO2 at 400, 800, 1200, 1800 hPa and gas gain from 1 to 5×105

  7. High-precision gas gain and energy transfer measurements in Ar–CO2 mixtures

    Şahin, Özkan; Veenhof, Rob

    2014-01-01

    Ar–CO2 is a Penning mixture since a fraction of the energy stored in Ar 3p53d3p53d and higher excited states can be transferred to ionize CO2 molecules. In the present work, concentration and pressure dependence of Penning transfer rate and photon feedback parameter in Ar–CO2 mixtures have been investigated with recent systematic high-precision gas gain measurements which cover the range 1–50% CO2 at 400, 800, 1200, 1800 hPa and gas gain from 1 to 5×105.

  8. Design on X-band Wideband and High-gain Multi-layer Microstrip Antenna

    Soufian LAKRIT

    2014-07-01

    Full Text Available In this paper, a wide-band and high-gain microstrip antenna with mullti-layer microstrip patch and an aperture-coupled feeding is proposed. The antenna has a condensed structure where the dimension is about 8.5mm by 7.5mm by 4.662mm leading to good bandwidths covering 8.05 GHz to 12.01 GHz (39.48%, and the gain is up to 5.23dB. The low expenses of this profile and its simple configuration allows for an its easy fabrication, with appropriation with wireless and satellite communication.

  9. On the high gain operation of low-pressure microdot gas avalanche chambers

    Microdot avalanche chambers (MDOT) equipped with thin semitransparent Cr photocathodes, were characterized with UV photons at low gas pressure. Gains superior to 104 were reached with gas multiplication at the dots. In a mode where preamplification in the gas volume precedes the additional dot multiplication, gains superior to 106 were measured at 30-60 torr of propane. The fast amplification mechanism results in narrow high amplitude pulses with 2-3 ns rise time, visible with no further electronic amplification means. We present here our preliminary results and briefly discuss potential applications. (orig.)

  10. Phase and gain control policies for robust active vibration control of flexible structures

    The interest of this paper is to develop a general and systematic robust control methodology for active vibration control of flexible structures. For this purpose, first phase and gain control policies are proposed to impose qualitative frequency-dependent requirements on the controller to consider a complete set of control objectives. Then the proposed control methodology is developed by employing phase and gain control policies in the dynamic output feedback H∞ control: according to the set of control objectives, phase and gain control policies incorporate necessary weighting functions and determine them in a rational and systematic way; on the other hand, with the appropriate weighting functions efficient H∞ control algorithms can automatically realize phase and gain control policies and generate a satisfactory H∞ controller. The proposed control methodology can be used for both SISO and MIMO systems with collocated or non-collocated sensors and actuators. In this paper, it is validated on a non-collocated piezoelectric cantilever beam. Both numerical simulations and experimental results demonstrate the effectiveness of the proposed control methodology. (paper)

  11. An Active Gain-control System for Avalanche Photo-Diodes under Moderate Temperature Variations

    Kataoka, J; Ikagawa, T; Kotoku, J; Kuramoto, Y; Tsubuku, Y; Saitô, T; Yatsu, Y; Kawai, N; Ishikawa, Y; Kawabata, N

    2006-01-01

    Avalanche photodiodes (APDs) are promising light sensor for various fields of experimental physics. It has been argued, however, that variation of APD gain with temperature could be a serious problem preventing APDs from replacing traditional photomultiplier tubes (PMTs) in some applications. Here we develop an active gain-control system to keep the APD gain stable under moderate temperature variations. As a performance demonstration of the proposed system, we have tested the response of a scintillation photon detector consisting of a 5x5 mm^2 reverse-type APD optically coupled with a CsI(Tl) crystal. We show that the APD gain was successfully controlled under a temperature variation of DT = 20deg, within a time-cycle of 6000 sec. The best FWHM energy resolution of 6.1+-0.2 % was obtained for 662 keV gamma-rays, and the energy threshold was as low as 6.5 keV, by integrating data from +20deg - 0deg cycles. The corresponding values for -20deg - 0deg cycles were 6.9+-0.2 % and 5.2 keV, respectively. These result...

  12. Pregnant women's perceptions of weight gain, physical activity, and nutrition using Theory of Planned Behavior constructs.

    Whitaker, Kara M; Wilcox, Sara; Liu, Jihong; Blair, Steven N; Pate, Russell R

    2016-02-01

    A better understanding of women's perceptions of weight gain and related behaviors during pregnancy is necessary to inform behavioral interventions. We used the Theory of Planned Behavior (TPB) to examine pregnant women's perceptions and intentions toward weight gain, physical activity (PA), and nutrition using a mixed methods study design. Women between 20 and 30 weeks gestation (n = 189) were recruited to complete an Internet-based survey. Salient beliefs toward weight gain, PA, and nutrition were captured through open-ended responses and content analyzed into themes. TPB constructs (attitude, subjective norm, perceived behavioral control, intentions) were examined using Pearson correlations and hierarchical linear regression models. Salient beliefs were consistent with the existing literature in non-pregnant populations, with the addition of many pregnancy-specific beliefs. TPB constructs accounted for 23-39 % of the variance in weight gain, PA, and nutrition intentions, and made varying contributions across outcomes. The TPB is a useful framework for examining women's weight-related intentions during pregnancy. Study implications for intervention development are discussed. PMID:26335313

  13. Limiting Excess Weight Gain in Healthy Pregnant Women: Importance of Energy Intakes, Physical Activity, and Adherence to Gestational Weight Gain Guidelines

    Tamara R. Cohen

    2013-01-01

    Full Text Available Few studies have investigated if compliance with energy intakes, physical activity, and weight gain guidelines attenuate postpartum weight retention (PPWR in mothers attending prenatal classes. We investigated whether (a daily energy intakes within 300 kcal of estimated energy requirements (EERs, (b walking more than 5000 steps/day, (c targeting the recommended weight gain goals for prepregnancy BMI, and/or (d achieving weekly or total gestational weight gain (GWG recommendations minimized PPWR in 54 women attending prenatal classes in Montreal/Ottawa, Canada. Participants completed a validated pregnancy physical activity questionnaire (PPAQ, 3 telephone-validated 24-hr dietary recalls, and wore a pedometer for one week. PPWR was measured 6 weeks after delivery. Results showed that 72% had healthy prepregnancy BMIs. However, 52% consumed >300 kcal/day in excess of their EER, 54% exceeded recommended GWG, and more overweight (93% than normal weight women (38% cited nonrecommended GWG targets. Following delivery, 33% were classified as overweight, and 17% were obese. Multiple logistic regressions revealed that women targeting “recommended weight gain advice” were 3 times more likely to meet total GWG recommendations (OR: 3.2, P<0.05; women who complied with weekly GWG goals minimized PPWR (OR: 4.2, P<0.02. In conclusion, appropriate GWG targets, lower energy intakes, and physical activity should be emphasized in prenatal education programs.

  14. Millimeter Wave Fabry-Perot Resonator Antenna Fed by CPW with High Gain and Broadband

    Xue-Xia Yang

    2016-01-01

    Full Text Available A novel millimeter wave coplanar waveguide (CPW fed Fabry-Perot (F-P antenna with high gain, broad bandwidth, and low profile is reported. The partially reflective surface (PRS and the ground form the F-P resonator cavity, which is filled with the same dielectric substrate. A dual rhombic slot loop on the ground acts as the primary feeding antenna, which is fed by the CPW and has broad bandwidth. In order to improve the antenna gain, metal vias are inserted surrounding the F-P cavity. A CPW-to-microstrip transition is designed to measure the performances of the antenna and extend the applications. The measured impedance bandwidth of S11 less than −10 dB is from 34 to 37.7 GHz (10.5%, and the gain is 15.4 dBi at the center frequency of 35 GHz with a 3 dB gain bandwidth of 7.1%. This performance of the antenna shows a tradeoff among gain, bandwidth, and profile.

  15. Simulation of DARMSTADT Free Electron Laser and a comparison of high gain Free Electron Laser

    Massey, Daniel S.

    2000-01-01

    The Free Electron Laser, with its wavelength tunability unlike any other laser, may be used in numerous future applications. These applications range from high energy laser weapons to surgical lasers for medical use. This thesis covers three separate topics concerning the FEL: the height of the separatrix for a tapered undulator, use of dimensionless parameters in a simple model and description for several high gain free electron lasers, and simulations of the Darmstadt free electron laser. T...

  16. Adaptive high gain observer based output feedback predictive controller for induction motor

    Hadj Saïd, S.; M'Sahli, F.; Mimouni, F; Farza, Mondher

    2013-01-01

    An accurate estimation of both rotor and stator resistances is usually required to achieve high performance control in induction machine drive systems. In our study, an output feedback predictive controller which is adaptive with respect to these parameters uncertainties is proposed. Such design attempts to a fully decoupling in speed and flux magnitude when conjoint estimation of the state and the critical parameters is performed. Precisely, two-stage of high gain observer are used to provid...

  17. Allele specific gain-of-function activity of p53 mutants in lung cancer cells

    Vaughan, Catherine A.; Frum, Rebecca; Pearsall, Isabella; Singh, Shilpa; Windle, Brad; Yeudall, Andrew; Deb, Swati P.; Deb, Sumitra

    2012-01-01

    p53 mutations are mostly single amino acid changes resulting in expression of a stable mutant protein with “gain of function” (GOF) activity having a dominant oncogenic role rather than simple loss of function of wild-type p53. Knock-down of mutant p53 in human lung cancer cell lines with different endogenous p53 mutants results in loss of GOF activity as shown by lowering of cell growth rate. Two lung cancer cell lines, ABC1 and H1437 carrying endogenous mutants p53–P278S and –R267P, both sh...

  18. Broadband optical gain in the normally dispersive region of a high-birefringence photonic crystal fiber

    Based on a designed high-birefringence photonic crystal fiber (HB-PCF) with two zero-dispersion wavelengths (ZDWs), the effect of pump parameters and Raman scattering on the modulation instability (MI) gain is comprehensively analyzed in this paper. An interesting result is found, in that only when the pump wavelength lies within an approximately 10 nm range of the zero-dispersion points in the normal dispersion region of the HB-PCF does a broadband gain characteristic appear. The Raman effect results in a combination of the gain spectra from the Stokes and anti-Stokes band, which finally promotes the formation of broadband amplification. Moreover, there exist an optimal pump wavelength and a suitable pump power along the fast axis or the slow axis of the fiber. With these optimal pump parameters, the total MI gain bandwidth finally reaches 159 nm for the fiber fast axis and 162 nm for the fiber slow axis. (paper)

  19. A differential low-voltage high gain current-mode integrated RF receiver front-end

    A differential low-voltage high gain current-mode integrated RF front end for an 802.11b WLAN is proposed. It contains a differential transconductance low noise amplifier (Gm-LNA) and a differential current-mode down converted mixer. The single terminal of the Gm-LNA contains just one MOS transistor, two capacitors and two inductors. The gate-source shunt capacitors, Cx1 and Cx2, can not only reduce the effects of gate-source Cgs on resonance frequency and input-matching impedance, but they also enable the gate inductance Lg1,2 to be selected at a very small value. The current-mode mixer is composed of four switched current mirrors. Adjusting the ratio of the drain channel sizes of the switched current mirrors can increase the gain of the mixer and accordingly increase the gain of RF receiver front-end. The RF front-end operates under 1 V supply voltage. The receiver RFIC was fabricated using a chartered 0.18 μm CMOS process. The integrated RF receiver front-end has a measured power conversion gain of 17.48 dB and an input referred third-order intercept point (IIP3) of -7.02 dBm. The total noise figure is 4.5 dB and the power is only 14 mW by post-simulations. (semiconductor integrated circuits)

  20. Design of a high-power, high-gain, 2nd harmonic, 22.848 GHz gyroklystron

    Veale, M.; P. Purohit; Lawson, W.

    2013-01-01

    In this paper we consider the design of a four-cavity, high-gain K-band gyroklystron experiment for high gradient structure testing. The frequency doubling gyroklystron utilizes a beam voltage of 500 kV and a beam current of 200 A from a magnetron injection gun (MIG) originally designed for a lower-frequency device. The microwave circuit features input and gain cavities in the circular TE011 mode and penultimate and output cavities that operate at the second harmonic in the TE021 mode. We inv...

  1. First lasing of a high-gain harmonic generation free-electron laser experiment

    We report on the first lasing of a high-gain harmonic generation (HGHG) free-electron laser (FEL). The experiment was conducted at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory (BNL). This is a BNL experiment in collaboration with the Advanced Photon Source (APS) at Argonne National Laboratory. A preliminary measurement gives a high-gain harmonic generation (HGHG) pulse energy that is 2 x 107 times larger than the spontaneous radiation, In a purely self-amplified spontaneous emission (SASE) mode of operation, the signal was measured as 10 times larger than the spontaneous radiation in the same distance (approximately2 m) through the same wiggler. This means the HGHG signal is 2 x 106 times larger than the SASE signal. To obtain the same saturated output power by the SASE process, the radiator would have to be 3 times longer (6 m)

  2. First lasing of a high-gain harmonic generation free- electron laser experiment

    We report on the first lasing of a high-gain harmonic generation (HGHG) free-electron laser (FEL). The experiment was conducted at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory (BNL). This is a BNL experiment in collaboration with the Advanced Photon Source (APS) at Argonne National Laboratory. A preliminary measurement gives a high-gain harmonic generation (HGHG) pulse energy that is 2x107 times larger than the spontaneous radiation. In a purely self-amplified spontaneous emission (SASE) mode of operation, the signal was measured as 10 times larger than the spontaneous radiation in the same distance (∼2 m) through the same wiggler. This means the HGHG signal is 2x106 times larger than the SASE signal. To obtain the same saturated output power by the SASE process, the radiator would have to be 3 times longer (6 m)

  3. Synchronization and secure communication of chaotic systems via robust adaptive high-gain fuzzy observer

    This paper proposes an alternative robust adaptive high-gain fuzzy observer design scheme and its application to synchronization and secure communication of chaotic systems. It is assumed that their states are immeasurable and their parameters are unknown. The structure of the proposed observer is represented by Takagi-Sugeno fuzzy model and has the integrator of the estimation error. It improves the performance of high-gain observer and makes the proposed observer robust against noisy measurements, uncertainties and parameter perturbations as well. Using Lyapunov stability theory, an adaptive law is derived to estimate the unknown parameters and the stability of the proposed observer is analyzed. Some simulation result of synchronization and secure communication of chaotic systems is given to present the validity of theoretical derivations and the performance of the proposed observer as an application.

  4. Mode control in a high gain relativistic klystron amplifier with 3 GW output power

    Higher mode excitation is very serious in the relativistic klystron amplifier, especially for the high gain relativistic amplifier working at tens of kilo-amperes. The mechanism of higher mode excitation is explored in the PIC simulation and it is shown that insufficient separation of adjacent cavities is the main cause of higher mode excitation. So RF lossy material mounted on the drift tube wall is adopted to suppress higher mode excitation. A high gain S-band relativistic klystron amplifier is designed for the beam current of 13 kA and the voltage of 1 MV. PIC simulation shows that the output power is 3.2 GW when the input power is only 2.8 kW. (authors)

  5. Microlens array-based high-gain screen design for direct projection head-up displays

    Hedili, M. Kıvanç; Ürey, Hakan; Freeman, Mark O.

    2013-01-01

    Microlens array-based high-gain screen design for direct projection head-up displays M. Kivanc Hedili,1 Mark O. Freeman,2 and Hakan Urey1,* 1Optical Microsystems Laboratory, Koc University, Rumelifeneri Yolu, Sarıyer, İstanbul 34450, Turkey 2Lost Lake Technology LLC, 21623 W. Lost Lake Rd., Snohomish, Washington 98296, USA *Corresponding author: Received 2 October 2012; revised 28 December 2012; accepted 29 December 2012; posted 18 January 2013 (Doc. ID 17...

  6. A Vehicle Haptic Steering by Wire System Based on High Gain GPI Observers

    A. Rodriguez-Angeles; H. Sira-Ramirez; J. A. Garcia-Antonio

    2014-01-01

    A vehicle steering by wire (SBW) haptic system based on high gain generalized proportional integral (GPI) observers is introduced. The observers are considered for the estimation of dynamic perturbations that are present at the tire and steering wheel. To ensure efficient tracking between the commanded steering wheel angle and the tire orientation angle, the estimated perturbations are on line canceled. As to provide a haptic interface with the driver, the estimated dynamic effects at the st...

  7. Gain reduction due to space charge at high counting rates in multiwire proportional chambers

    Measurements with a small MWPC of gas gain reduction, due to ion space charge at high counting rates, have been compared with theoretical predictions. The quantity ln(q/q0)/(q/q0), where (q/q0) is the relative reduced avalanche charge, has been found to be closely proportional to count rate, as predicted. The constant of proportionality is in good agreement with calculations made with a modified version of the original, simplified theory

  8. Nanoparticle-assisted high photoconductive gain in polymer/fullerene matrix

    Chen, Hsiang-Yu; Lo, Michael K. F.; Yang, Guanwen; Harold G. Monbouquette; Yang, Yang

    2008-01-01

    Polymer/inorganic nanocrystal composites1–10 offer an attractive means to combine the merits of organic and inorganic materials into novel electronic and photonic systems. However, many applications of these composites are limited by the solubility11 and distribution of nanocrystals (NCs) in polymer matrices. Here, a high photoconductive gain has been achieved by blending cadmium telluride (CdTe) nanoparticles (NPs) into a polymer/fullerene matrix followed by a solvent annealing12 process. Th...

  9. Design and frequency-domain analysis of linear high-gain integral-derivative observer

    Wang, Xinhua

    2015-01-01

    In this paper, a slimple linear high-gain integral-derivative observer is presented based on singular perturbation technique. The proposed integral-derivative observer can estimate synchronously the multiple integrals and derivatives of a signal. The merits of the presented integral-derivative observer include its synchronous estimation of integrals and derivatives, simple implementation, sufficient stochastic noises rejection and almost no drift phenomenon. The theoretical results are confir...

  10. Optimization of single-step tapering amplitude and energy detuning for high-gain FELs

    Li, He-Ting; Jia, Qi-Ka

    2015-01-01

    We put forward a method to optimize the single-step tapering amplitude of undulator strength and initial energy tuning of electron beam to maximize the saturation power of high gain free-electron lasers (FELs), based on the physics of longitudinal electron beam phase space. Using the FEL simulation code GENESIS, we numerically demonstrate the accuracy of the estimations for parameters corresponding to the linac coherent light source and the Tesla test facility.

  11. Longitudinal Coherence Preservation and Chirp Evolution in a High Gain Laser Seeded Free Electron Laser Amplifier

    Murphy, J.B.; /BNL, NSLS; Wu, Juhao; /SLAC; Wang, X.J.; Watanabe, T.; /BNL, NSLS

    2006-06-07

    In this letter we examine the start-up of a high gain free electron laser in which a frequency-chirped coherent seed laser pulse interacts with a relativistic electron beam. A Green function formalism is used to evaluate the initial value problem. We have fully characterized the startup and evolution through the exponential growth regime. We obtain explicit expressions for the pulse duration, bandwidth and chirp of the amplified light and show that the FEL light remains fully longitudinally coherent.

  12. Nonlinear high-gain observers with integral action: Application to bioreactors

    Rodríguez-Mata, A.; Torres-Munoz, J.; Domínguez, A.R.; Hernandez-Villagran, D.; Čelikovský, Sergej

    Merida City: IEEE, 2011, s. 1-6. ISBN 978-1-4577-1011-7. [The 8th International Conference on Electrical Engineering, Computing Science and Automatic Control 2011 (CCE 2011). Merida City (MX), 26.10.2011-28.10.2011] Institutional research plan: CEZ:AV0Z10750506 Keywords : High-gain observers * integral action * microalgae Subject RIV: BC - Control Systems Theory http://www.ieee.org/conferences_events/conferences/conferencedetails/index.html?Conf_ID=19270

  13. A high voltage gain quasi Z-source isolated DC/DC converter

    Siwakoti, Yam P.; Blaabjerg, Frede; Loh, Poh Chiang;

    2014-01-01

    A compact quasi-Z-source DC/DC converter is presented with high voltage gain, isolated output, and improved efficiency. The improvements in size and performance were achieved by using a square wave inverter with only two output switches driving an isolating transformer in push-pull mode, followed...... constructed and tested. The efficiency at full load varied from 89.0% to 97.4% as the input voltage changed from 44 V to 82 V....

  14. High energy gain, high quality laser particle accelerator development at JAERI-APR

    Recent activities related to laser-plasma acceleration at Advanced Photon Research Center, Japan Atomic Energy Research Institute are presented. Gas density measurements of a pulsed gas valve and wakefield measurements have been performed with two types of interferometers. A wakefield of 20 GV/m excited in the gas-jet plasma has been obtained at a plasma density of 7x1017 cm-3. We have shown by 1D-3V particle-in-cell simulation that a high quality electron beam with a transverse emittance of 0.3 π mm-mrad and with an energy of 7.0±0.5 MeV can be produced using a colliding optical injection. Our proposed experiments using a 100 TW laser beam and a 150 MeV electron beam are also presented

  15. Multiwavelength Dispersion-Tuned Actively Mode-Locked Erbium-Doped Fibre Ring Laser with Gain Competition Suppression

    PAN Shi-Long; LOU Cai-Yun

    2006-01-01

    Multiwavelength dispersion-tuned actively mode-locked erbium-doped fibre ring laser is demonstrated by incorporating a section of highly nonlinear fibre (HNLF) in the laser cavity. The HNLF and the time gate element (modulator) in the fibre laser successfully suppress the gain competition in the erbium-doped fibre, and thus enable multiwavelength operation. Simultaneous generation of 10 GHz pulses up to eight different wavelengths is achieved. Wavelength, spacing and modes number tuning are investigated by changing fibre cavity length, dispersion, and erbium-doped fibre amplifier power, respectively.

  16. Pregnant women’s perceptions of weight gain, physical activity, and nutrition using Theory of Planned Behavior constructs

    Whitaker, Kara M.; Wilcox, Sara; Liu, Jihong; Blair, Steven N; Russell R. Pate

    2015-01-01

    A better understanding of women’s perceptions of weight gain and related behaviors during pregnancy is necessary to inform behavioral interventions. We used the Theory of Planned Behavior (TPB) to examine pregnant women’s perceptions and intentions toward weight gain, physical activity (PA), and nutrition using a mixed methods study design. Women between 20 and 30 weeks gestation (n = 189) were recruited to complete an Internet-based survey. Salient beliefs toward weight gain, PA, and nutriti...

  17. Design of high-gain, wideband antenna using microwave hyperbolic metasurface

    Zhao, Yan

    2016-05-01

    In this work, we apply hyperbolic metasurfaces (HMSs) to design high-gain and wideband antennas. It is shown that HMSs formed by a single layer of split-ring resonators (SRRs) can be excited to generate highly directive beams. In particular, we suggest two types of the SRR-HMS: a capacitively loaded SRR (CLSRR)-HMS and a substrate-backed double SRR (DSRR)-HMS. Both configurations ensure that the periodicity of the structures is sufficiently small for satisfying the effective medium theory. For the antenna design, we propose a two-layer-stacked configuration for the 2.4 GHz frequency band based on the DSRR-HMS excited by a folded monopole. Measurement results confirm numerical simulations and demonstrate that an antenna gain of more than 5 dBi can be obtained for the frequency range of 2.1 - 2.6 GHz, with a maximum gain of 7.8 dBi at 2.4 GHz.

  18. Design of high-gain, wideband antenna using microwave hyperbolic metasurface

    Yan Zhao

    2016-05-01

    Full Text Available In this work, we apply hyperbolic metasurfaces (HMSs to design high-gain and wideband antennas. It is shown that HMSs formed by a single layer of split-ring resonators (SRRs can be excited to generate highly directive beams. In particular, we suggest two types of the SRR-HMS: a capacitively loaded SRR (CLSRR-HMS and a substrate-backed double SRR (DSRR-HMS. Both configurations ensure that the periodicity of the structures is sufficiently small for satisfying the effective medium theory. For the antenna design, we propose a two-layer-stacked configuration for the 2.4 GHz frequency band based on the DSRR-HMS excited by a folded monopole. Measurement results confirm numerical simulations and demonstrate that an antenna gain of more than 5 dBi can be obtained for the frequency range of 2.1 - 2.6 GHz, with a maximum gain of 7.8 dBi at 2.4 GHz.

  19. dc SQUID electronics based on adaptive noise cancellation and a high open-loop gain controller

    A low-noise SQUID readout electronics with a high slew rate and an automatic gain control feature has been developed. Flux noise levels of 5x10-7Φ0/√Hz at 1 kHz and 2x10-6Φ0/√Hz at 1 Hz have been measured with this readout scheme. The system tolerates sinusoidal disturbances having amplitudes up to 140 Φ0 at 1 kHz without loosing lock. The electronics utilizes a cooled GaAs FET to control the cancellation of the voltage noise of the room temperature amplifier, a PI3/2 controller to provide a high open-loop gain at low frequencies, and a square-wave flux and offset voltage modulation to enable automatic control of the noise reduction. The cutoff frequency of the flux-locked-loop is 300 kHz and the feedback gain is more than 130 dB at 10 Hz. (orig.)

  20. Olanzapine-high potency antipsychotic drug inducing significant weight gain: A case report

    Marić Nađa P.

    2008-01-01

    Full Text Available INTRODUCTION Olanzapine is a second generation antipsychotic (SGA with a high level of therapeutic effectiveness in schizophrenia and other psychotic disorders. Along with the positive therapeutic effects, an increase of the body weight frequently occurs. According to the literature, the average weight gain is about 6-7 kg during several months of treatment. This could be valued as a moderate weight increase. CASE OUTLINE This article presents a case of a young female with schizophrenia, without clinical improvement with several antipsychotics (clozapine, risperidone, haloperidol and with the occurrence of significant neurological side effects. The treatment started with olanzapine (baseline was associated with good initial response (PANSS reduction 20% in the first two weeks and the improvement was maintained further on (PANSS reduction 50% after 16 weeks. Significant increase (20 kg, 40% in weight appeared during the following 16 weeks (BMI at baseline 17.9 kg/m2; BMI 16 weeks later 25.1 kg/m2. CONCLUSION High effectiveness of olanzapine in schizophrenia symptoms reduction was accompanied by a significant weight gain. However, this drug leads to impaired glucoregulation, dyslipidaemia etc. It also increases the risk of diabetes and cardio-vascular diseases, i.e. the main causes of mortality in schizophrenia after a suicide. Therefore, clinicians are suggested to focus on possible predictors of weight gain during olanzapine therapy, and act accordingly in order to prevent serious health consequences.

  1. A Vehicle Haptic Steering by Wire System Based on High Gain GPI Observers

    A. Rodriguez-Angeles

    2014-01-01

    Full Text Available A vehicle steering by wire (SBW haptic system based on high gain generalized proportional integral (GPI observers is introduced. The observers are considered for the estimation of dynamic perturbations that are present at the tire and steering wheel. To ensure efficient tracking between the commanded steering wheel angle and the tire orientation angle, the estimated perturbations are on line canceled. As to provide a haptic interface with the driver, the estimated dynamic effects at the steering rack are fed back to the steering wheel, yielding a master-slave haptic system with bilateral communication. For implementation purposes few sensors and minimum knowledge of the dynamic model are required, which is a major advantage compared to other approaches. Only position tracking errors are fed back, while all other signals are estimated by the high gain GPI observers. The scheme is robust to uncertainty on the input gain and cancels dynamic perturbation effects such as friction and aligning forces on the tire. Experimental results are presented on a prototype platform.

  2. A bootstrapped, low-noise, and high-gain photodetector for shot noise measurement

    We presented a low-noise, high-gain photodetector based on the bootstrap structure and the L-C (inductance and capacitance) combination. Electronic characteristics of the photodetector, including electronic noise, gain and frequency response, and dynamic range, were verified through a single-frequency Nd:YVO4 laser at 1064 nm with coherent output. The measured shot noise of 50 μW laser was 13 dB above the electronic noise at the analysis frequency of 2 MHz, and 10 dB at 3 MHz. And a maximum clearance of 28 dB at 2 MHz was achieved when 1.52 mW laser was illuminated. In addition, the photodetector showed excellent linearities for both DC and AC amplifications in the laser power range between 12.5 μW and 1.52 mW

  3. High gain broadband amplification of ultraviolet pulses in optical parametric chirped pulse amplifier.

    Wnuk, Paweł; Stepanenko, Yuriy; Radzewicz, Czesław

    2010-04-12

    We report on a high gain amplification of broadband ultraviolet femtosecond pulses in an optical parametric chirped pulse amplifier. Broadband ultraviolet seed pulses were obtained by an achromatic frequency doubling of the output from a femtosecond Ti:Sapphire oscillator. Stretched seed pulses were amplified in a multipass parametric amplifier with a single BBO crystal pumped by a ns frequency quadrupled Nd:YAG laser. A noncollinear configuration was used for a broadband amplification. The total (after compression) amplification of 2.510(5) was achieved, with compressed pulse energy of 30 microJ and pulse duration of 24 fs. We found that the measured gain was limited by thermal effects induced by the absorption of the pump laser by color centers created in the BBO crystal. PMID:20588633

  4. Inkjet printing of novel wideband and high gain antennas on low-cost paper substrate

    Cook, Benjamin Stassen

    2012-09-01

    A complete characterization of the inkjet printing process using metallic nanoparticle inks on a paper substrate for microwave frequencies up to 12.5 GHz as well as its application to low-cost, high gain and wideband antenna design are demonstrated in this work. Laser and heat sintering of metallic nanoparticles are compared on paper substrate for the first time which demonstrate immense cost and time benefits of laser sintering. The antennas fabricated using the characterized process include a Vivaldi for the UWB band which exhibits a significantly higher gain of up to 8 dBi as compared to the currently published inkjet printed antennas, and a novel slow-wave log periodic dipole array which employs a new miniaturization technique to show 20% width reduction. © 1963-2012 IEEE.

  5. Design of high-gain, wideband antenna using microwave hyperbolic metasurface

    Yan Zhao

    2016-01-01

    In this work, we apply hyperbolic metasurfaces (HMSs) to design high-gain and wideband antennas. It is shown that HMSs formed by a single layer of split-ring resonators (SRRs) can be excited to generate highly directive beams. In particular, we suggest two types of the SRR-HMS: a capacitively loaded SRR (CLSRR)-HMS and a substrate-backed double SRR (DSRR)-HMS. Both configurations ensure that the periodicity of the structures is sufficiently small for satisfying the effective medium theory. Fo...

  6. A new Design for an High Gain Vacuum Photomultiplier: The Silicon PMT Used as Amplification Stage

    Photons detection will continue to be a channel of great interest in the High Energy Physics and Astroparticle Physics fields for medium and big scale experiments in the next future. Thus, new solutions for photon detectors, that overcome the current limits of classical photomultipliers, are welcomed. We propose an innovative design for a hybrid, modern, high gain Vacuum Silicon Photomultiplier Tube (VSiPMT) which is boosted by the recent Geiger-mode avalanche silicon photodiode (G-APD) for which a massive production is today available.

  7. Modeling and Analysis of Transformerless High Gain Buck-boost DC-DC Converters

    Vu Tran

    2014-12-01

    Full Text Available This paper proposes a transfomerless switched capacitor buck boost converter model, which provides higher voltage gain and higher efficiency when compared to the conventional buck boost converter. The averaged model based on state-space description is analyzed in the paper. The simulation results are presented to confirm the capability of the converter to generate high voltage ratios. The comparison between the proposed model and the traditional model is also provided to reveal the improvement. The proposed converter is suitable for for a wide application which requires high step-up DC-DC converters such as DC micro-grids and solar electrical energy.

  8. Effects of bandwidth, compression speed, and gain at high frequencies on preferences for amplified music.

    Moore, Brian C J

    2012-09-01

    This article reviews a series of studies on the factors influencing sound quality preferences, mostly for jazz and classical music stimuli. The data were obtained using ratings of individual stimuli or using the method of paired comparisons. For normal-hearing participants, the highest ratings of sound quality were obtained when the reproduction bandwidth was wide (55 to 16000 Hz) and ripples in the frequency response were small (less than ± 5 dB). For hearing-impaired participants listening via a simulated five-channel compression hearing aid with gains set using the CAM2 fitting method, preferences for upper cutoff frequency varied across participants: Some preferred a 7.5- or 10-kHz upper cutoff frequency over a 5-kHz cutoff frequency, and some showed the opposite preference. Preferences for a higher upper cutoff frequency were associated with a shallow high-frequency slope of the audiogram. A subsequent study comparing the CAM2 and NAL-NL2 fitting methods, with gains slightly reduced for participants who were not experienced hearing aid users, showed a consistent preference for CAM2. Since the two methods differ mainly in the gain applied for frequencies above 4 kHz (CAM2 recommending higher gain than NAL-NL2), these results suggest that extending the upper cutoff frequency is beneficial. A system for reducing "overshoot" effects produced by compression gave small but significant benefits for sound quality of a percussion instrument (xylophone). For a high-input level (80 dB SPL), slow compression was preferred over fast compression. PMID:23172008

  9. High gain observer synchronization for a class of time-delay chaotic systems. Application to secure communications.

    Cherrier, Estelle; M'Saad, Mohammed; Farza, Mondher

    2010-01-01

    This work investigates high gain observer design to synchronize a time-delay chaotic system. It is shown that the underlying class of nonlinear systems can be put into the canonical observable form, and thus high gain observer design framework can be extended to chaotic synchronization problem. Our approach is motivated by its simplicity of implementation: the observer gain synthesis relies on the explicit resolution of a time-invariant algebraic Lyapunov equation, which leads to a single par...

  10. High gain observer based synchronization for a class of time-delay chaotic systems: application to secure communications.

    Cherrier, Estelle; M'Saad, Mohammed

    2009-01-01

    This work investigates high gain observer design to synchronize a time-delay chaotic system. It is shown that the underlying class of nonlinear systems can be put into the canonical observable form, and thus high gain observer design framework can be extended to chaotic synchronization problem. Our approach is motivated by its simplicity of implementation: the observer gain synthesis relies on the explicit resolution of a time-invariant algebraic Lyapunov equation, which leads to a single par...

  11. Design of High Gain and Broadband Antennas at 60 GHz for Underground Communications Systems

    Yacouba Coulibaly

    2012-01-01

    Full Text Available A new broadband and high gain dielectric resonator antenna for millimeter wave is presented. The investigated antenna configuration consists of a periodic square ring frequency selective surfaces on a superstrate, an aperture-coupled scheme feed, an intermediate substrate, and a cylindrical dielectric resonator. This antenna is designed to cover the ISM frequency band at 60 GHz (57 GHz–64 GHz. It was numerically designed using CST microwave Studio simulation software package. Another prototype with a plain dielectric superstrate is also studied for comparison purposes. A bandwidth of 13.56% at the centered frequency of 61.34 GHz and a gain of 11 dB over the entire ISM band have been achieved. A maximum gain of 14.26 dB is obtained at 60 GHz. This is an enhancement of 9 dB compared to a single DRA. HFSS is used to validate our antenna designs. Good agreement between the results of the two softwares is obtained. With these performances, these antennas promise to be useful in the design of future wireless underground communication systems operating in the unlicensed 60 GHz frequency band.

  12. High-Gain Textile Antenna Array System for Off-Body Communication

    Maria Lucia Scarpello

    2012-01-01

    Full Text Available A novel high-gain textile antenna array system, fully integrated into a rescue-worker’s vest and operating in the Industrial, Scientific, and Medical wireless band (2.4–2.4835 GHz, is presented. The system comprises an array consisting of four tip-truncated equilateral triangular microstrip patch antennas (ETMPAs, a power divider, line stretchers, and coaxial cables. The array is vertically positioned on the human torso to produce a narrow beam in elevation, as such reducing fading and allowing to steer the maximum gain in a small angular sector centered around the broadside direction. To allow simple low-cost beam steering, we specifically minimize mutual coupling by using a relative large distance between the patches and by selecting the ETMPA element as the most suited topology from three potential patch geometries. Moreover, we investigate the stability of return loss and mutual coupling characteristics under different relative humidity conditions, when bending the array, when placing the system on-body, and when covering it by different textile layers. Reflection coefficient and gain patterns are simulated and measured for the antenna system in free space and placed on the human body.

  13. A differential low-voltage high gain current-mode integrated RF receiver front-end

    Wang Chunhua; Ma Minglin; Sun Jingru; Du Sichun; Guo Xiaorong; He Haizhen, E-mail: wch1227164@sina.com [School of Information Science and Technology, Hunan University, Changsha 410082 (China)

    2011-02-15

    A differential low-voltage high gain current-mode integrated RF front end for an 802.11b WLAN is proposed. It contains a differential transconductance low noise amplifier (G{sub m}-LNA) and a differential current-mode down converted mixer. The single terminal of the G{sub m}-LNA contains just one MOS transistor, two capacitors and two inductors. The gate-source shunt capacitors, C{sub x1} and C{sub x2}, can not only reduce the effects of gate-source C{sub gs} on resonance frequency and input-matching impedance, but they also enable the gate inductance L{sub g1,2} to be selected at a very small value. The current-mode mixer is composed of four switched current mirrors. Adjusting the ratio of the drain channel sizes of the switched current mirrors can increase the gain of the mixer and accordingly increase the gain of RF receiver front-end. The RF front-end operates under 1 V supply voltage. The receiver RFIC was fabricated using a chartered 0.18 {mu}m CMOS process. The integrated RF receiver front-end has a measured power conversion gain of 17.48 dB and an input referred third-order intercept point (IIP3) of -7.02 dBm. The total noise figure is 4.5 dB and the power is only 14 mW by post-simulations. (semiconductor integrated circuits)

  14. Broadband microwave phase shifter based on high speed cross gain modulation in quantum dot semiconductor optical amplifiers

    Chen, Yaohui; Mørk, Jesper

    2009-01-01

    We present a scheme to achieve tunable ~180 degrees microwave phase shifts at frequencies exceeding 100 GHz based on high speed cross gain modulation in quantum dot semiconductor optical amplifiers.......We present a scheme to achieve tunable ~180 degrees microwave phase shifts at frequencies exceeding 100 GHz based on high speed cross gain modulation in quantum dot semiconductor optical amplifiers....

  15. Individual Differences in Striatum Activity to Food Commercials Predict Weight Gain in Adolescents

    Yokum, Sonja; Gearhardt, Ashley N.; Harris, Jennifer L.; Brownell, Kelly D.; Stice, Eric

    2014-01-01

    Objective Adolescents view thousands of food commercials annually, but little is known about how individual differences in neural response to food commercials relate to weight gain. To add to our understanding of individual risk factors for unhealthy weight gain and environmental contributions to the obesity epidemic, we tested the associations between reward region (striatum and orbitofrontal cortex [OFC]) responsivity to food commercials and future change in Body Mass Index (BMI). Design and Methods Adolescents (N = 30) underwent a scan session at baseline while watching a television show edited to include 20 food commercials and 20 non-food commercials. BMI was measured at baseline and 1-year follow-up. Results Activation in the striatum, but not OFC, in response to food commercials relative to non-food commercials and in response to food commercials relative to the television show was positively associated with change in BMI over 1-year follow-up. Baseline BMI did not moderate these effects. Conclusions The results suggest that there are individual differences in neural susceptibility to food advertising. These findings highlight a potential mechanism for the impact of food marketing on adolescent obesity. PMID:25155745

  16. Ultranarrow linewidth and high gain of an optical cavity with enhanced self-Kerr nonlinearity in quantum dot molecules

    The enhanced self-Kerr nonlinearity of quantum dot molecules may be used to realize optical cavities with an ultranarrow linewidth and high gain. The resonant tunneling induces constructive interference for the self-Kerr nonlinearity, and then a narrow gain window with large normal dispersion appears with frequency detuning. The competition between linear and nonlinear dispersion leads to strong normal dispersion of the total susceptibility, which significantly narrows the cavity linewidth; the nonlinear gain introduces the total gain effects contributing to high transmission. Simulation results show that the cavity linewidth could be narrowed by nearly 30 times and the transmission peak enhanced about 40 times compared with a linear case. (letters)

  17. 110-GHz High-gain Flip-chip InP HEMT Amplifier with Resin Encapsulation on an Organic Substrate

    Masuda, Satoshi; Kira, Hidehiko; Hirose, Tatsuya

    2004-01-01

    A high-gain amplifier monolithic microwave integrated circuit (MMIC) was developed using InP HEMT technology with inverted microstrip lines. The six-stage amplifier demonstrated a gain of 30 dB at 110 GHz. We also fabricated a resin-sealed flip-chip MMIC on a highly isolated cost-effective glass-epoxy substrate, achieving a gain of 28 dB at 110 GHz. To the best of our knowledge, this is the highest gain in the W-band for a flip-chip MMIC sealed with resin.

  18. Sub-Poissonian shot noise of a high internal gain injection photon detector.

    Memis, Omer Gokalp; Katsnelson, Alex; Kong, Soon-Cheol; Mohseni, Hooman; Yan, Minjun; Zhang, Shuang; Hossain, Tim; Jin, Niu; Adesida, Ilesanmi

    2008-08-18

    The noise performance of an infrared injection photon detector with very high internal gain was investigated at a wavelength of 1.55 mum. The devices showed sub-Poissonian shot noise with Fano factors around 0.55 at 0.7 V at room temperature. Optical to electrical conversion factors of 3000 electrons per absorbed photon were recorded at 0.7 V. The change in noise-equivalent power with respect to bias voltage was evaluated. The optical to electrical conversion factor and Fano factor were measured under increasing illumination and compared to theoretical expectations. PMID:18711508

  19. High-gain textile antenna array system for off-body communication

    Dries Vande Ginste; Hendrik Rogier; Luigi Vallozzi; Maria Lucia Scarpello

    2012-01-01

    A novel high-gain textile antenna array system, fully integrated into a rescue-worker’s vest and operating in the Industrial, Scientific, and Medical wireless band (2.4–2.4835 GHz), is presented. The system comprises an array consisting of four tip-truncated equilateral triangular microstrip patch antennas (ETMPAs), a power divider, line stretchers, and coaxial cables. The array is vertically positioned on the human torso to produce a narrow beam in elevation, as such reducing fading and allo...

  20. Self-Seeded FEL Wavelength Extension with High-Gain Harmonic Generation

    Zeng, Ling; Zhao, Gang; Huang, Senlin; Ding, Yuantao; Huang, Zhirong; Marcus, Gabriel; Liu, Kexin

    2016-01-01

    We study a self-seeded high-gain harmonic generation (HGHG) free-electron laser (FEL) scheme to extend the wavelength of a soft X-ray FEL. This scheme uses a regular self-seeding monochromator to generate a seed laser at the wavelength of 1.52 nm, followed by a HGHG configuration to produce coherent, narrow-bandwidth harmonic radiations at the GW level. The 2nd and 3rd harmonic radiation are investigated with start-to-end simulations. Detailed studies on the FEL performance and shot-to-shot fluctuations are presented.

  1. High Gain Antenna System Deployment Mechanism Integration, Characterization, and Lessons Learned

    Parong, Fil; Russell, Blair; Garcen, Walter; Rose, Chris; Johnson, Chris; Huber, Craig

    2014-01-01

    The integration and deployment testing of the High Gain Antenna System for the Global Precipitation Measurement mission is summarized. The HGAS deployment mechanism is described. The gravity negation system configuration and its influence on vertical, ground-based, deployment tests are presented with test data and model predictions. A focus is made on the late discovery and resolution of a potentially mission degrading deployment interference condition. The interaction of the flight deployment mechanism, gravity negation mechanism, and use of dynamic modeling is described and lessons learned presented.

  2. Analysis of FEL-based CeC amplification at high gain limit

    An analysis of Coherent electron Cooling (CeC) amplifier based on 1D Free Electron Laser (FEL) theory was previously performed with exact solution of the dispersion relation, assuming electrons having Lorentzian energy distribution. At high gain limit, the asymptotic behavior of the FEL amplifier can be better understood by Taylor expanding the exact solution of the dispersion relation with respect to the detuning parameter. In this work, we make quadratic expansion of the dispersion relation for Lorentzian energy distribution and investigate how longitudinal space charge and electrons@@@ energy spread affect the FEL amplification process.

  3. Method and system for modulation of gain suppression in high average power laser systems

    Bayramian, Andrew James

    2012-07-31

    A high average power laser system with modulated gain suppression includes an input aperture associated with a first laser beam extraction path and an output aperture associated with the first laser beam extraction path. The system also includes a pinhole creation laser having an optical output directed along a pinhole creation path and an absorbing material positioned along both the first laser beam extraction path and the pinhole creation path. The system further includes a mechanism operable to translate the absorbing material in a direction crossing the first laser beam extraction laser path and a controller operable to modulate the second laser beam.

  4. Measurements of enthalpy-stimulated-scattering gain in the active medium of an iodine photodissociation laser

    Korol' kov, K.S.; Krylov, A.IU.; Nosach, O.IU.; Orlov, E.P. (Fizicheskii Institut, Moscow (USSR))

    1990-07-01

    A method is developed for determining the absolute gain of the nonstationary enthalpy stimulated scattering (NESS) of laser radiation by temperature waves by means of direct measurements of fundamental and impurity beam gains in the laser amplifier. The NESS gain is investigated as a function of the working gas mixture pressure in iodine photodissociation lasers. 11 refs.

  5. Thermoregulation of water foraging honeybees--balancing of endothermic activity with radiative heat gain and functional requirements.

    Kovac, Helmut; Stabentheiner, Anton; Schmaranzer, Sigurd

    2010-12-01

    Foraging honeybees are subjected to considerable variations of microclimatic conditions challenging their thermoregulatory ability. Solar heat is a gain in the cold but may be a burden in the heat. We investigated the balancing of endothermic activity with radiative heat gain and physiological functions of water foraging Apis mellifera carnica honeybees in the whole range of ambient temperatures (T(a)) and solar radiation they are likely to be exposed in their natural environment in Middle Europe. The mean thorax temperature (T(th)) during foraging stays was regulated at a constantly high level (37.0-38.5 °C) in a broad range of T(a) (3-30 °C). At warmer conditions (T(a)=30-39 °C) T(th) increased to a maximal level of 45.3 °C. The endothermic temperature excess (difference of T(body)-T(a) of living and dead bees) was used to assess the endogenously generated temperature elevation as a correlate of energy turnover. Up to a T(a) of ∼30 °C bees used solar heat gain for a double purpose: to reduce energetic expenditure and to increase T(th) by about 1-3 °C to improve force production of flight muscles. At higher T(a) they exhibited cooling efforts to get rid of excess heat. A high T(th) also allowed regulation of the head temperature high enough to guarantee proper function of the bees' suction pump even at low T(a). This shortened the foraging stays and this way reduced energetic costs. With decreasing T(a) bees also reduced arrival body weight and crop loading to do both minimize costs and optimize flight performance. PMID:20705071

  6. Technology developments and first measurements of Low Gain Avalanche Detectors (LGAD) for high energy physics applications

    This paper introduces a new concept of silicon radiation detector with intrinsic multiplication of the charge, called Low Gain Avalanche Detector (LGAD). These new devices are based on the standard Avalanche Photo Diodes (APD) normally used for optical and X-ray detection applications. The main differences to standard APD detectors are the low gain requested to detect high energy charged particles, and the possibility to have fine segmentation pitches: this allows fabrication of microstrip or pixel devices which do not suffer from the limitations normally found [1] in avalanche detectors. In addition, a moderate multiplication value will allow the fabrication of thinner devices with the same output signal of standard thick substrates. The investigation of these detectors provides important indications on the ability of such modified electrode geometry to control and optimize the charge multiplication effect, in order to fully recover the collection efficiency of heavily irradiated silicon detectors, at reasonable bias voltage, compatible with the voltage feed limitation of the CERN High Luminosity Large Hadron Collider (HL-LHC) experiments [2]. For instance, the inner most pixel detector layers of the ATLAS tracker will be exposed to fluences up to 2×1016 1 MeV neq/cm2, while for the inner strip detector region fluences of 1×1015 neq/cm2 are expected. The gain implemented in the non-irradiated devices must retain some effect also after irradiation, with a higher multiplication factor with respect to standard structures, in order to be used in harsh environments such those expected at collider experiments

  7. Lossless Airy Surface Polaritons in a Metamaterial via Active Raman Gain

    Zhang, Qi; Huang, Guoxiang

    2016-01-01

    We propose a scheme to realize a lossless propagation of linear and nonlinear Airy surface polaritons (SPs) via active Raman gain (ARG). The system we suggest is a planar interface superposed by a negative index metamaterial (NIMM) and a dielectric, where three-level quantum emitters are doped. By using the ARG from the quantum emitters and the destructive interference effect between the electric and magnetic responses from the NIMM, we show that not only the Ohmic loss of the NIMM but also the light absorption of the quantum emitters can be completely eliminated. As a result, non-diffractive Airy SPs may propagate for very long distance without attenuation. We also show that the Kerr nonlinearity of the system can be largely enhanced due to the introduction of the quantum emitters and hence lossless Airy surface polaritonic solitons with very low power can be generated in the system.

  8. Operating synchrotron light sources with a high gain free electron laser

    Di Mitri, S.; Cornacchia, M.

    2015-11-01

    Since the 1980s synchrotron light sources have been considered as drivers of a high repetition rate (RR), high gain free electron laser (FEL) inserted in a by-pass line or in the ring itself. As of today, the high peak current required by the laser is not deemed to be compatible with the standard multi-bunch filling pattern of synchrotrons, and in particular with the operation of insertion device (ID) beamlines. We show that this problem can be overcome by virtue of magnetic bunch length compression in a ring section, and that, after lasing, the beam returns to equilibrium conditions without beam quality disruption. Bunch length compression brings a double advantage: the high peak current stimulates a high gain FEL emission, while the large energy spread makes the beam less sensitive to the FEL heating and to the microwave instability in the ring. The beam’s large energy spread at the undulator is matched to the FEL energy bandwidth through a transverse gradient undulator. Feasibility of lasing at 25 nm is shown for the Elettra synchrotron light source at 1 GeV, and scaling to shorter wavelengths as a function of momentum compaction, beam energy and transverse emittance in higher energy, larger rings is discussed. For the Elettra case study, a low (100 Hz) and a high (463 kHz) FEL RR are considered, corresponding to an average FEL output power at the level of ∼1 W (∼1013 photons per pulse) and ∼300 W (∼1011 photons per pulse), respectively. We also find that, as a by-product of compression, the ∼5 W Renieri’s limit on the average FEL power can be overcome. Our conclusion is that existing and planned synchrotron light sources may be made compatible with this new hybrid IDs-plus-FEL operational mode, with little impact on the standard beamlines functionality.

  9. Monopole Charge Domain in High-Gain Gallium Arsenide Photoconductive Switches

    施卫; 陈二柱; 张显斌; 李琦

    2002-01-01

    Considering that semi-insulating gallium arsenide photoconductive switches can be triggered into the high gain mode and no reliable theories can account for the observed transient characteristics, we propose the monopole charge domain model to explain the peculiar switching phenomena occurring in the high gain mode and we discuss the requirements for the lock-on switching. During operation on this mode, the applied field across the switch and the lock-on field are all larger than the Gunn threshold field. Our developed monopole charge domain is based on the transferred-electron effect, but the domain is only composed of large numbers of electrons piled up due to the negative differential mobility. Using the model and taking the physical mechanism of the avalanche impact ionization and recombination radiation into consideration, we interpret the typical phenomena of the lock-on effect, such as the time delay between the beginning of optical illumination and turning-on of the switch, and the conduction mechanism of the sustaining phase. Under different conditions of bias field intensity and incident light energy, the time delay of the switching is calculated. The results show that the physical mechanisms of impact ionization and recombination radiation occurring in the monopole charge domain are responsible for the lock-on switching.

  10. Polarization beam combination technique for gain saturation effect compensation in high-energy systems

    Chen, Junchi; Peng, Yujie; Su, Hongpeng; Leng, Yuxin

    2016-06-01

    To compensate for the gain saturation effect in the high-energy laser amplifier, a modified polarization beam combination (PBC) method is introduced to reshape temporal waveform of the injected laser pulse to obtain a controlled high-energy laser pulse shape after amplification. One linearly polarized beam is divided into two orthogonal polarized beams, which spatially recombine together collinearly after propagating different optical paths with relative time delay in PBC structure. The obtained beam with polarization direction being rotated by the following half wave plate is divided and combined again to reform a new beam in another modified polarization beam structure. The reformed beam is injected into three cascaded laser amplifiers. The amplified pulse shape can be controlled by the incident pulse shape and amplifier gain, which is agreeable to the simulation by the Frank-Nodvik equations. Based on the simple method, the various temporal waveform of output pulse with tunable 7 to 20 ns pulse duration can be obtained without interferometric fringes.

  11. Relative contributions of energy expenditure on physical activity, body composition and weight gain to the evolution of impaired glucose tolerance to Frank diabetes

    In modem technological societies the requirement for physical work is diminished and access to food is unrestricted. Under these circumstances a large proportion of the population will gain weight and develop obesity and diabetes. At the individual level, genetic and behavioural factors must combine to lead to an imbalance between energy intake and its expenditure. Weight gain, especially rapid weight gain in a population appears to increase the risk of diabetes sharply. Thus understanding the route to weight gain and obesity, and the modulatory effects of physical activity on development of glucose intolerance is critical to credible intervention strategies to reverse or prevent diabetes in populations especially those in transitional societies. In this proposal we will examine the quantitative importance of non-resting energy expenditure (EE) in populations with rising levels of obesity and high prevalence of diabetes. (author)

  12. High gain x-ray lasers pumped by transient collisional excitation

    Dunn, J., LLNL

    1998-06-16

    We present recent results of x-ray laser amplification of spontaneous emission in Ne-like and Ni-like transient collisional excitation schemes. The plasma formation, ionization and collisional excitation can be optimized using two laser pulses of 1 ns and 1 ps duration at table-top energies of 5 J in each beam. High gain of 35 cm{sup -1} has been measured on the 147 {Angstrom} 4d{r_arrow}4p J=0{r_arrow}1 transition of Ni-like Pd and is a direct consequence of the nonstationary population inversion produced by the high intensity picosecond pulse. We report the dependence of the x-ray laser line intensity on the laser plasma conditions and compare the experimental measurements with hydrodynamic and atomic kinetics simulations for Ne-like and Ni-like lasing.

  13. High-pass filtering and dynamic gain regulation enhance vertical bursts transmission along the mossy fiber pathway of cerebellum

    Jonathan Mapelli

    2010-05-01

    Full Text Available Signal elaboration in the cerebellum mossy fiber input pathway presents controversial aspects, especially concerning gain regulation and the spot-like (rather than beam-like appearance of granular-to-molecular layer transmission. By using voltage-sensitive dye (VSD imaging in rat cerebellar slices (Mapelli et al., 2010, we found that mossy fiber bursts optimally excited the granular layer above ~50 Hz and the overlaying molecular layer above ~100 Hz, thus generating a cascade of high-pass filters. NMDA receptors enhanced transmission in the granular, while GABA-A receptors depressed transmission in both the granular and molecular layer. Burst transmission gain was controlled through a dynamic frequency-dependent involvement of these receptors. Moreover, while high-frequency transmission was enhanced along vertical lines connecting the granular to molecular layer, no high-frequency enhancement was observed along the parallel fiber axis in the molecular layer. This was probably due to the stronger effect of Purkinje cell GABA-A receptor-mediated inhibition occurring along the parallel fibers than along the granule cell axon ascending branch. The consequent amplification of burst responses along vertical transmission lines could explain the spot-like activation of Purkinje cells observed following punctuate stimulation in vivo .

  14. Small sized high-gain PHEMT high-power amplifiers for X-BAND applications

    Hek, A.P. de; Hunneman, P.A.H.

    2000-01-01

    The development of two small sized broadband X-band high-power amplifiers is discussed. The amplifiers are realised with the help of the pseudomorphic HEMT technology of the Fraunhofer Institute for Applied Solid State Physics (FhG-IAF). With the help of this technology the feasibility of integrating a driver and high-power amplifier on a single, small sized, chip is demonstrated. This integration will reduce the number of chips necessary in a Transmit/Receive (T/R) module used in e.g. a phas...

  15. Design of a high-power, high-gain, 2nd harmonic, 22.848 GHz gyroklystron

    In this paper we consider the design of a four-cavity, high-gain K-band gyroklystron experiment for high gradient structure testing. The frequency doubling gyroklystron utilizes a beam voltage of 500 kV and a beam current of 200 A from a magnetron injection gun (MIG) originally designed for a lower-frequency device. The microwave circuit features input and gain cavities in the circular TE011 mode and penultimate and output cavities that operate at the second harmonic in the TE021 mode. We investigate the MIG performance and study the behavior of the circuit for different values of perpendicular to parallel velocity ratio (α= V⊥/ Vz). This microwave tube is expected to be able to produce at least 20 MW of power in 1μs pulses at a repetition rate of at least 120 Hz. A maximum efficiency of 26% and a large signal gain of 58 dB under zero-drive stable conditions were simulated for a velocity ratio equal to 1.35.

  16. Design of a high-power, high-gain, 2nd harmonic, 22.848 GHz gyroklystron

    Veale, M.; Purohit, P.; Lawson, W.

    2013-08-01

    In this paper we consider the design of a four-cavity, high-gain K-band gyroklystron experiment for high gradient structure testing. The frequency doubling gyroklystron utilizes a beam voltage of 500 kV and a beam current of 200 A from a magnetron injection gun (MIG) originally designed for a lower-frequency device. The microwave circuit features input and gain cavities in the circular TE011 mode and penultimate and output cavities that operate at the second harmonic in the TE021 mode. We investigate the MIG performance and study the behavior of the circuit for different values of perpendicular to parallel velocity ratio (α = V⊥ / Vz). This microwave tube is expected to be able to produce at least 20 MW of power in 1μs pulses at a repetition rate of at least 120 Hz. A maximum efficiency of 26% and a large signal gain of 58 dB under zero-drive stable conditions were simulated for a velocity ratio equal to 1.35.

  17. Design of a high-power, high-gain, 2nd harmonic, 22.848 GHz gyroklystron

    M. Veale

    2013-08-01

    Full Text Available In this paper we consider the design of a four-cavity, high-gain K-band gyroklystron experiment for high gradient structure testing. The frequency doubling gyroklystron utilizes a beam voltage of 500 kV and a beam current of 200 A from a magnetron injection gun (MIG originally designed for a lower-frequency device. The microwave circuit features input and gain cavities in the circular TE011 mode and penultimate and output cavities that operate at the second harmonic in the TE021 mode. We investigate the MIG performance and study the behavior of the circuit for different values of perpendicular to parallel velocity ratio (α = V⊥ / Vz. This microwave tube is expected to be able to produce at least 20 MW of power in 1μs pulses at a repetition rate of at least 120 Hz. A maximum efficiency of 26% and a large signal gain of 58 dB under zero-drive stable conditions were simulated for a velocity ratio equal to 1.35.

  18. Design of a high-power, high-gain, 2nd harmonic, 22.848 GHz gyroklystron

    Veale, M. [University of California, Berkeley, CA, 24720 (United States); Purohit, P. [Qualcomm Technologies, Inc. USA (United States); Lawson, W. [University of Maryland, College Park, MD 20742 (United States)

    2013-08-15

    In this paper we consider the design of a four-cavity, high-gain K-band gyroklystron experiment for high gradient structure testing. The frequency doubling gyroklystron utilizes a beam voltage of 500 kV and a beam current of 200 A from a magnetron injection gun (MIG) originally designed for a lower-frequency device. The microwave circuit features input and gain cavities in the circular TE{sub 011} mode and penultimate and output cavities that operate at the second harmonic in the TE{sub 021} mode. We investigate the MIG performance and study the behavior of the circuit for different values of perpendicular to parallel velocity ratio (α= V{sub ⊥}/ V{sub z}). This microwave tube is expected to be able to produce at least 20 MW of power in 1μs pulses at a repetition rate of at least 120 Hz. A maximum efficiency of 26% and a large signal gain of 58 dB under zero-drive stable conditions were simulated for a velocity ratio equal to 1.35.

  19. Taxing away M&A : the effect of corporate capital gains taxes on acquisition activity

    Feld, Lars P.; Ruf, Martin; Schreiber, Ulrich; Todtenhaupt, Maximilian; Voget, Johannes

    2016-01-01

    Taxing capital gains is an important obstacle to the efficient allocation of resources because it imposes a transaction cost on the vendor which locks in appreciated assets by raising the vendor's reservation price in prospective transactions. For M&As, this effect has been intensively studied with regard to share-holder taxation, whereas empirical evidence on the effect of capital gains taxes paid by corporations is scarce. This paper analyzes how corporate level taxation of capital gains af...

  20. Gain Evaluation of Micro-Channel-Plate Photomultipliers in the Upgraded High-B Test Facility at Jefferson Lab

    Barber, Corinne; DIRC at EIC Collaboration

    2015-10-01

    The High-B test facility at Thomas Jefferson National Accelerator Facility allows researchers to evaluate the gain of compact photon sensors, such as Micro-Channel-Plate Photomultipliers (MCP-PMTs), in magnetic fields up to 5 T. These ongoing studies support the development of a Detector of Internally Reflected Cherenkov light (DIRC) to be used in an Electron Ion Collider (EIC). Here, we present our summer 2015 activities to upgrade and improve the facility, and we show results for MCP-PMT gain changes in high B-fields. To monitor the light stability delivered to the MCP-PMTs being tested, we implemented a Silicon Photomultiplier (SiPM) in the setup and calibrated the ADC reading this sensor. A 405-nm Light-Emitting Diode (LED) housed in an optical tube compatible with neutral density filters was also installed. The filters provide an alternative way of reducing the light output of the LED to operate the MCP-PMTs in a single-photon mode. We calibrated a set of filters by means of a photodiode and measured the photon flux at multiple positions relative to the LED. This information helped us to design 3D-printed holders unique to each MCP-PMT so that the photocathode receives the greatest amount of light. The improvements to the setup allow for more precise PMT gain evaluation. This team includes 7 collaborators/co-authors besides myself: Yordanka Ilieva, Kijun Park, Greg Kalicy, Carl Zorn, Pawel Nadel-Turonski, Tongtong Cao, and Lee.

  1. New results of the high-gain harmonic generation free-electron laser experiment

    We report on the experimental investigation of high-gain harmonic generation carried out at the Accelerator Test Facility at Brookhaven National Laboratory. A seed CO2 laser at a wavelength of 10.6 μm was used to generate FEL output at a 5.3-μm wavelength. The duration of the output pulse was measured using a second-harmonic intensity autocorrelator, and the coherence length was measured using an interferometer. We also measured the energy distribution of the electron beam after it exited the second undulator, observing behavior consistent with that is expected at saturation. The intensity of the harmonic components of the output at 2.65 and 1.77 μm was determined relative to that of the 5.3-μm fundamental. Finally, using a corrector magnet upstream of the radiator, steering effects on the trajectories of the electron and light beams were studied

  2. Single-Phase Z-source Matrix Converter with High Voltage Gain

    A.Gopi

    2013-02-01

    Full Text Available This paper proposes a new type of converter called Single Phase Z-source Matrix Converter (SPZMC. The SPZMC is an ac-to-ac converter device. Simulated using diode bridge bidirectional switch cell. The simulation is performed in different loads with fixed input and variable output frequency. Pulse Width Modulation (PWM switching strategy is used to obtain the variable frequency. The Z-sourcenetwork provided the good voltage regulation with change in load conditions. The proposed converter presented improvements in power factor and achieved low total harmonic distortion (THD level. AndSPZMC also improves the output waveform quality with high voltage gain.. The simulation results are verified with the prototype hardware model. The results are presented to verify the operation.

  3. Photovoltaic Response Characteristics of GaAs Photoconductive Switches Under High Gain Mode

    DAI Hui-ying; SHI Wei

    2007-01-01

    Given is the experiment results in which the laser pulses of 1 046 nm and 532 nm are used to trigger the semi-insulation GaAs photoconductive semiconductor switch(PCSS) with an electrode distance of 4 mm. And made is an analysis of the switch's photovoltaic response characteristics under the high gain mode when the biased field is bigger than the Geng effect field. Also a theory is presented that the main reason for the photovoltaic pulse response delay is the transmission of charge domain, caused by the presence of EL2 energy level in the chip material. Finally, the transmission time of charge domain is calculated and a result that inosculates with the experiment is attained.

  4. Gestational weight gain by reduced brain melanocortin activity affects offspring energy balance in rats

    Heinsbroek, A. C. M.; van Dijk, G.

    2009-01-01

    Introduction: Excessive gestational body weight gain of mothers may predispose offspring towards obesity and metabolic derangements. It is difficult to discern the effects of maternal obesogenic factors-such as diet and/or thrifty genetic predisposition-from gestational weight gain per se. Methods:

  5. A Coherent Compton Backscattering High Gain FEL using an X-Band Microwave Undulator

    Pellegrini, C; Travish, G

    2005-01-01

    We describe a proposed high-gain FEL using an X-band microwave undulator and operating at a wavelength of about 0.5 μm. The FEL electron beam energy is 65 MeV. The beam is produced by the NLCTA X-band linac at SLAC, using an S-band high-brightness photoinjector. The undulator consists of a circular waveguide with an rf wave counter-propagating with respect to the electron beam. The undulator is powered with two high-power X-band klystrons and a dual-moded pulse compressor recently developed at SLAC. This system is capable of delivering flat-top rf pulses of up to 400 ns and a few hundred megawatts. The equivalent undulator period is 1.4 cm, the radius of the circular pipe is 1 cm, and the undulator parameter is about 0.4 for a helical undulator configuration, obtained using two cross-polarized TE modes, or larger for a planar configuration, using one rf polarization. The undulator is about four meters long. The FEL will reach saturation within this distance when operated in a SASE mode. We describe t...

  6. Fluorene- and benzofluorene-cored oligomers as low threshold and high gain amplifying media

    Kazlauskas, Karolis, E-mail: karolis.kazlauskas@ff.vu.lt; Kreiza, Gediminas; Bobrovas, Olegas; Adomėnienė, Ona; Adomėnas, Povilas; Juršėnas, Saulius [Institute of Applied Research, Vilnius University, Saulėtekio 9-III, LT-10222 Vilnius (Lithuania); Jankauskas, Vygintas [Department of Solid State Electronics, Vilnius University, Saulėtekio 9-III, LT-10222 Vilnius (Lithuania)

    2015-07-27

    Deliberate control of intermolecular interactions in fluorene- and benzofluorene-cored oligomers was attempted via introduction of different-length alkyl moieties to attain high emission amplification and low amplified spontaneous emission (ASE) threshold at high oligomer concentrations. Containing fluorenyl peripheral groups decorated with different-length alkyl moieties, the oligomers were found to express weak concentration quenching of emission, yet excellent carrier drift mobilities (close to 10{sup −2} cm{sup 2}/V/s) in the amorphous films. Owing to the larger radiative decay rates (>1.0 × 10{sup 9 }s{sup −1}) and smaller concentration quenching, fluorene-cored oligomers exhibited down to one order of magnitude lower ASE thresholds at higher concentrations as compared to those of benzofluorene counterparts. The lowest threshold (300 W/cm{sup 2}) obtained for the fluorene-cored oligomers at the concentration of 50 wt % in polymer matrix is among the lowest reported for solution-processed amorphous films in ambient conditions, what makes the oligomers promising for lasing application. Great potential in emission amplification was confirmed by high maximum net gain (77 cm{sup −1}) revealed for these compounds. Although the photostability of the oligomers was affected by photo-oxidation, it was found to be comparable to that of various organic lasing materials including some commercial laser dyes evaluated under similar excitation conditions.

  7. A new high-gain vacuum photomultiplier based upon the amplification of a Geiger-mode p-n junction

    The future astroparticle experiments will study both energetic phenomena and extremely rare events from astrophysical sources. Since most of these families of experiments are carried out by using scintillation phenomena, Cherenkov or fluorescence radiation, the development of photosensitive detectors seems to be the right way to increase the experimental sensitivity. We therefore propose an innovative design for a modern, high gain, silicon-based Vacuum Silicon Photomultiplier Tube (VSiPMT), which combines three fully established and well-understood technologies: the manufacture of hemispherical vacuum tubes with the possibility of very large active areas, the photocathode glass deposition and the recent Geiger-mode avalanche silicon photodiode (G-APD) for which a mass production is today available. This new design, based on G-APD as the electron multiplier, allows overcoming the limits of the classical PMT dynode chain

  8. All AlGaN epitaxial structure solar-blind avalanche photodiodes with high efficiency and high gain

    Wu, Hualong; Wu, Weicong; Zhang, Hongxian; Chen, Yingda; Wu, Zhisheng; Wang, Gang; Jiang, Hao

    2016-05-01

    Solar-blind avalanche photodiodes were fabricated with an all AlGaN-based epitaxial structure on sapphire by metal–organic chemical vapor deposition. The devices demonstrate a maximum responsivity of 114.1 mA/W at 278 nm and zero bias, corresponding to an external quantum efficiency (EQE) of 52.7%. The EQE improves to 64.8% under a bias of ‑10 V. Avalanche gain higher than 2 × 104 was obtained at a bias of ‑140 V. The high performance is attributed to the all AlGaN-based p–i–n structure comprised of undoped and Si-doped n-type Al0.4Ga0.6N on a high quality AlN layer and highly conductive p-type AlGaN grown with In-surfactant-assisted Mg-delta doping.

  9. Whey protein reduces early life weight gain in mice fed a high-fat diet

    Tranberg, Britt; Hellgren, Lars; Lykkesfeldt, Jens; Sejrsen, Kristen; Jeamet, Aymeric; Rune, Ida; Ellekilde, Merete; Nielsen, Dennis Sandris; Hansen, Axel Kornerup

    2013-01-01

    An increasing number of studies indicate that dairy products, including whey protein, alleviate several disorders of the metabolic syndrome. Here, we investigated the effects of whey protein isolate (whey) in mice fed a high-fat diet hypothesising that the metabolic effects of whey would be...... associated with changes in the gut microbiota composition. Five-week-old male C57BL/6 mice were fed a high-fat diet ad libitum for 14 weeks with the protein source being either whey or casein. Faeces were collected at week 0, 7, and 13 and the fecal microbiota was analysed by denaturing gradient gel...... weight gain was similar resulting in a 15% lower final body weight in the whey group relative to casein (34.0±1.0 g vs. 40.2±1.3 g, P<0.001). Food intake was unaffected by protein source throughout the study period. Fasting insulin was lower in the whey group (P<0.01) and glucose clearance was improved...

  10. Inertial Confinement Fusion: steady progress towards ignition and high gain (summary talk)

    Most important recent advances in inertial confinement fusion (ICF) are highlighted. With the construction of the NIF and LMJ facilities, and a number of improvements in the target design, the conventional indirect-drive approach is making a steady progress towards demonstration of ignition and high gain. The development of the polar direct-drive concept made also the prospects for direct-drive ignition on the NIF extremely favorable. A substantial progress has been reported from the Institute of Laser Engineering in Osaka on exploration of the fast-ignition approach to ICF. Parallel to that, multi-wire Z-pinches have become a competitive driver option for achieving ignition at a lowest possible cost. In heavy ion fusion, experiments have been devoted so far to studying the generation, transport, and final focusing of high-current ion beams. A new concept for a power plant with a heavy-ion driver, based on a cylindrical direct-drive target compressed and ignited (in the fast-ignition mode) by two separate beams of very energetic (Ei > or ∼ 0.5 GeV/u) heavy ions, has been proposed. (author)

  11. A scalable-low cost architecture for high gain beamforming antennas

    Bakr, Omar

    2010-10-01

    Many state-of-the-art wireless systems, such as long distance mesh networks and high bandwidth networks using mm-wave frequencies, require high gain antennas to overcome adverse channel conditions. These networks could be greatly aided by adaptive beamforming antenna arrays, which can significantly simplify the installation and maintenance costs (e.g., by enabling automatic beam alignment). However, building large, low cost beamforming arrays is very complicated. In this paper, we examine the main challenges presented by large arrays, starting from electromagnetic and antenna design and proceeding to the signal processing and algorithms domain. We propose 3-dimensional antenna structures and hybrid RF/digital radio architectures that can significantly reduce the complexity and improve the power efficiency of adaptive array systems. We also present signal processing techniques based on adaptive filtering methods that enhance the robustness of these architectures. Finally, we present computationally efficient vector quantization techniques that significantly improve the interference cancellation capabilities of analog beamforming architectures. © 2010 IEEE.

  12. Individual Differences in Striatum Activity to Food Commercials Predict Weight Gain in Adolescents

    Yokum, Sonja; Gearhardt, Ashley N; Harris, Jennifer L.; Brownell, Kelly D.; Stice, Eric

    2014-01-01

    Objective Adolescents view thousands of food commercials annually, but little is known about how individual differences in neural response to food commercials relate to weight gain. To add to our understanding of individual risk factors for unhealthy weight gain and environmental contributions to the obesity epidemic, we tested the associations between reward region (striatum and orbitofrontal cortex [OFC]) responsivity to food commercials and future change in Body Mass Index (BMI). Design an...

  13. A novel 4H-SiC lateral bipolar junction transistor structure with high voltage and high current gain

    Deng, Yong-Hui; Xie, Gang; Wang, Tao; Sheng, Kuang

    2013-09-01

    In this paper, a novel structure of a 4H-SiC lateral bipolar junction transistor (LBJT) with a base field plate and double RESURF in the drift region is presented. Collector-base junction depletion extension in the base region is restricted by the base field plate. Thin base as well as low base doping of the LBJT therefore can be achieved under the condition of avalanche breakdown. Simulation results show that thin base of 0.32 μm and base doping of 3 × 1017 cm-3 are obtained, and corresponding current gain is as high as 247 with avalanche breakdown voltage of 3309 V when the drift region length is 30 μm. Besides, an investigation of a 4H-SiC vertical BJT (VBJT) with comparable breakdown voltage (3357 V) shows that the minimum base width of 0.25 μm and base doping as high as 8 × 1017 cm-3 contribute to a maximum current gain of only 128.

  14. Studies of relative gain and timing response of fine-mesh photomultiplier tubes in high magnetic fields

    Sulkosky, V; Barber, C; Cao, T; Ilieva, Y; Jin, K; Kalicy, G; Park, K; Ton, N; Zheng, X

    2016-01-01

    We investigated the use of Hamamatsu fine-mesh photomultiplier tube assemblies H6152-70 and H6614-70 with regards to their gain and timing resolution in magnetic fields up to 1.9 T. Our results show that the H6614-70 assembly can operate reliably in magnetic fields exceeding 1.5 T, while preserving a reasonable timing resolution even with a gain reduction of a factor of approximately 100. The reduction of the relative gain of the H6152-70 is similar to the H6614-70's near 1.5 T, but its timing resolution worsens considerably at this high field.

  15. Studies of relative gain and timing response of fine-mesh photomultiplier tubes in high magnetic fields

    Sulkosky, Vincent A. [Univ. of Virginia, Charlottesville, VA (United States); Allison-Russell, Lyndsey L. [Hampton Univ., Hampton, VA (United States); Barber, Corinne C. [Univ. of South Carolina, Columbia, SC (United States); Cao, Tongtong [Univ. of South Carolina, Columbia, SC (United States); Ilieva, Yordanka [Univ. of South Carolina, Columbia, SC (United States); Jin, Kai [Univ. of Virginia, Charlottesville, VA (United States); Kalicy, Grzegorz [Old Dominion Univ., Norfolk, VA (United States); Park, K. [Old Dominion Univ., Norfolk, VA (United States); Ton, N. [Univ. of Virginia, Charlottesville, VA (United States); Zheng, Xiaochao [Univ. of Virginia, Charlottesville, VA (United States)

    2016-05-01

    We investigated the use of Hamamatsu fine-mesh photomultiplier tube assemblies H6152-70 and H6614-70 with regards to their gain and timing resolution in magnetic fields up to 1.9 T. Our results show that the H6614-70 assembly can operate reliably in magnetic fields exceeding 1.5 T, while preserving a reasonable timing resolution even with a gain reduction of a factor of ~100. The reduction of the relative gain of the H6152-70 is similar to the H6614-70's near 1.5 T, but its timing resolution worsens considerably at this high field.

  16. Integrated Three-Voltage-Booster DC-DC Converter to Achieve High Voltage Gain with Leakage-Energy Recycling for PV or Fuel-Cell Power Systems

    Chih-Lung Shen; Hong-Yu Chen; Po-Chieh Chiu

    2015-01-01

    In this paper, an integrated three-voltage-booster DC-DC (direct current to direct current) converter is proposed to achieve high voltage gain for renewable-energy generation systems. The proposed converter integrates three voltage-boosters into one power stage, which is composed of an active switch, a coupled-inductor, five diodes, and five capacitors. As compared with conventional high step-up converters, it has a lower component count. In addition, the features of leakage-energy recycling...

  17. Spacecraft Angular Rates Estimation with Gyrowheel Based on Extended High Gain Observer.

    Liu, Xiaokun; Yao, Yu; Ma, Kemao; Zhao, Hui; He, Fenghua

    2016-01-01

    A gyrowheel (GW) is a kind of electronic electric-mechanical servo system, which can be applied to a spacecraft attitude control system (ACS) as both an actuator and a sensor simultaneously. In order to solve the problem of two-dimensional spacecraft angular rate sensing as a GW outputting three-dimensional control torque, this paper proposed a method of an extended high gain observer (EHGO) with the derived GW mathematical model to implement the spacecraft angular rate estimation when the GW rotor is working at large angles. For this purpose, the GW dynamic equation is firstly derived with the second kind Lagrange method, and the relationship between the measurable and unmeasurable variables is built. Then, the EHGO is designed to estimate and calculate spacecraft angular rates with the GW, and the stability of the designed EHGO is proven by the Lyapunov function. Moreover, considering the engineering application, the effect of measurement noise in the tilt angle sensors on the estimation accuracy of the EHGO is analyzed. Finally, the numerical simulation is performed to illustrate the validity of the method proposed in this paper. PMID:27089347

  18. Spacecraft Angular Rates Estimation with Gyrowheel Based on Extended High Gain Observer

    Xiaokun Liu

    2016-04-01

    Full Text Available A gyrowheel (GW is a kind of electronic electric-mechanical servo system, which can be applied to a spacecraft attitude control system (ACS as both an actuator and a sensor simultaneously. In order to solve the problem of two-dimensional spacecraft angular rate sensing as a GW outputting three-dimensional control torque, this paper proposed a method of an extended high gain observer (EHGO with the derived GW mathematical model to implement the spacecraft angular rate estimation when the GW rotor is working at large angles. For this purpose, the GW dynamic equation is firstly derived with the second kind Lagrange method, and the relationship between the measurable and unmeasurable variables is built. Then, the EHGO is designed to estimate and calculate spacecraft angular rates with the GW, and the stability of the designed EHGO is proven by the Lyapunov function. Moreover, considering the engineering application, the effect of measurement noise in the tilt angle sensors on the estimation accuracy of the EHGO is analyzed. Finally, the numerical simulation is performed to illustrate the validity of the method proposed in this paper.

  19. High speed gain coupled DFB laser diode integrated with MQW electroabsorption modulator

    Kim, M G; Park, S S; Oh, D K; Lee, H T; Kim, H M; Pyun, K E

    1998-01-01

    We have demonstrated stable modulation characteristics of the gain coupled distributed feedback(GC-DFB) laser diode integrated with butt-coupled InGaAsP/InGaAsP strain compensated MQW(multiple-Quantum-well) modulator for high speed optical transmission. For this purpose, we have adopted the InGaAsP/InGaAsP strain compensated MQW structure for the EA modulator and n-doped InGaAs absorptive grating for DFB laser. The typical threshold current and slope efficiency were about 15 mA and 0.1 mW/mA, respectively. The extinction ratio of fabricated integrated device was about 15 dB at -2 V, and the small signal bandwidth was shown to be around 17GHz. We also found that the alpha parameter becomes negative at below a -0.6 V bias voltage. We transmitted 10 Gbps NRZ electrical signal over 90 km of standard single mode optical fiber (SMF). A clearly opened eye diagram was observed in the modulated output.

  20. High speed gain coupled DFB laser diode integrated with MQW electroabsorption modulator

    We have demonstrated stable modulation characteristics of the gain coupled distributed feedback(GC-DFB) laser diode integrated with butt-coupled InGaAsP/InGaAsP strain compensated MQW(multiple-Quantum-well) modulator for high speed optical transmission. For this purpose, we have adopted the InGaAsP/InGaAsP strain compensated MQW structure for the EA modulator and n-doped InGaAs absorptive grating for DFB laser. The typical threshold current and slope efficiency were about 15 mA and 0.1 mW/mA, respectively. The extinction ratio of fabricated integrated device was about 15 dB at -2 V, and the small signal bandwidth was shown to be around 17GHz. We also found that the α parameter becomes negative at below a -0.6 V bias voltage. We transmitted 10 Gbps NRZ electrical signal over 90 km of standard single mode optical fiber (SMF). A clearly opened eye diagram was observed in the modulated output

  1. Design parameters of the high gain harmonic generation experiment using Cornell undulator A at the ATF

    The authors present the design parameters of a high gain harmonic generation (HGHG) FEL experiment to be carried out at the accelerator test facility (ATF) at BNL, in collaboration with APS. This experiment is a proof-of-principle experiment for the DUV-FEL at BNL. In the HGHG experiment they plan to double the frequency of a CO2 seed laser by utilizing a 0.76 m long 9 period undulator (named the Mini Undulator), a 2 m long 60 period undulator (named the Cornell Undulator A), and a 0.3 m electromagnet chicane (the dispersive section). The first undulator will be used in conjunction with the CO2 seed laser to generate a ponderomotive force that will bunch the electron beam. The bunching will then be enhanced by the dispersion section. The second undulator, the Cornell Undulator A, tuned to the second harmonic of the seed laser will serve as the radiator. In the beginning of the radiator the bunched beam will produce coherent emission (characterized by a quadratic growth of the radiated power), then the radiation will be amplified exponentially. They plan to study the evolution of the various radiation growth mechanisms as well as the coherence of the doubled, exponentially amplified radiation

  2. Progress towards a high-gain and robust target design for heavy ion fusion

    Henestroza, Enrique; Grant Logan, B.

    2012-07-01

    Recently [E. Henestroza et al., Phys. Plasmas 18, 032702 (2011)], a new inertial-fusion target configuration, the X-target, using one-sided axial illumination has been explored. This class of target uses annular and solid-profile heavy ion beams to compress and ignite deuterium-tritium (DT) fuel that fills the interior of metal cases that have side-view cross sections in the shape of an "X." X-targets using all-DT-filled metal cases imploded by three annular ion beams resulted in fuel densities of ˜50 g/cm3 at peak compression, and fusion gains of ˜50, comparable to heavy ion driven hohlraum targets [D. A. Callahan-Miller and M. Tabak, Phys. Plasmas 7, 2083 (2000)]. This paper discusses updated X-target configurations that incorporate inside the case a propellant (plastic) and a pusher (aluminum) surrounding the DT fuel. The updated configurations are capable of assembling higher fuel areal densities ˜2 g/cm2 using two annular beams to implode the target to peak DT densities ˜100 g/cm3, followed by a fast-ignition solid ion beam which heats the high-density fuel to thermonuclear temperatures in ˜200 ps to start the burn propagation, obtaining gains of ˜300. These targets have been modeled using the radiation-hydrodynamics code HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] in two- and three- dimensions to study the properties of the implosion as well as the ignition and burn propagation phases. At typical Eulerian mesh resolutions of a few microns, the aluminum-DT interface shows negligible Rayleigh-Taylor (RT) and Richtmyer-Meshkov instability growth; also, the shear flow of the DT fuel as it slides along the metal X-target walls, which drives the RT and Kelvin Helmholtz instabilities, does not have a major effect on the burning rate. An analytic estimate of the RT instability process at the Al-DT interface shows that the aluminum spikes generated during the pusher deceleration phase would not reach the ignition zone in time to affect the burning

  3. Progress towards a high-gain and robust target design for heavy ion fusion

    Henestroza, Enrique; Grant Logan, B. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2012-07-15

    Recently [E. Henestroza et al., Phys. Plasmas 18, 032702 (2011)], a new inertial-fusion target configuration, the X-target, using one-sided axial illumination has been explored. This class of target uses annular and solid-profile heavy ion beams to compress and ignite deuterium-tritium (DT) fuel that fills the interior of metal cases that have side-view cross sections in the shape of an 'X.' X-targets using all-DT-filled metal cases imploded by three annular ion beams resulted in fuel densities of {approx}50 g/cm{sup 3} at peak compression, and fusion gains of {approx}50, comparable to heavy ion driven hohlraum targets [D. A. Callahan-Miller and M. Tabak, Phys. Plasmas 7, 2083 (2000)]. This paper discusses updated X-target configurations that incorporate inside the case a propellant (plastic) and a pusher (aluminum) surrounding the DT fuel. The updated configurations are capable of assembling higher fuel areal densities {approx}2 g/cm{sup 2} using two annular beams to implode the target to peak DT densities {approx}100 g/cm{sup 3}, followed by a fast-ignition solid ion beam which heats the high-density fuel to thermonuclear temperatures in {approx}200 ps to start the burn propagation, obtaining gains of {approx}300. These targets have been modeled using the radiation-hydrodynamics code HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] in two- and three- dimensions to study the properties of the implosion as well as the ignition and burn propagation phases. At typical Eulerian mesh resolutions of a few microns, the aluminum-DT interface shows negligible Rayleigh-Taylor (RT) and Richtmyer-Meshkov instability growth; also, the shear flow of the DT fuel as it slides along the metal X-target walls, which drives the RT and Kelvin Helmholtz instabilities, does not have a major effect on the burning rate. An analytic estimate of the RT instability process at the Al-DT interface shows that the aluminum spikes generated during the pusher deceleration phase

  4. Effects of gain ripples in semiconductor optical amplifiers on very high speed lightwave systems

    In this paper, the authors report on experimental and theoretical investigations of an 11 Gbit/s lightwave system employing a 1500 nm traveling wave amplifier with gain ripples of larger than 1.7 dB. They found that at 11 Gbits/s, severe system degradations in the form of intersymbol interference and large extinction ratio penalty occur as the gain ripple increases, particularly for laser wavelengths located on the positive slope of the gain curve. Complete eye closure can occur in the worst situation. The InGaAsP traveling-wave semiconductor amplifier employed in the experiment is a buried-heterostructure device 500 μm long with a gain peak at 1551 nm, fabricated with 9 degrees angle facets with ZrO2 anti-reflection coating on both sides

  5. Gaining A Geological Perspective Through Active Learning in the Large Lecture Classroom

    Kapp, J. L.; Richardson, R. M.; Slater, S. J.

    2008-12-01

    NATS 101 A Geological Perspective is a general education course taken by non science majors. We offer 600 seats per semester, with four large lecture sections taught by different faculty members. In the past we have offered optional once a week study groups taught by graduate teaching assistants. Students often feel overwhelmed by the science and associated jargon, and many are prone to skipping lectures altogether. Optional study groups are only attended by ~50% of the students. Faculty members find the class to be a lot of work, mainly due to the grading it generates. Activities given in lecture are often short multiple choice or true false assignments, limiting the depth of understanding we can evaluate. Our students often lack math and critical thinking skills, and we spend a lot of time in lecture reintroducing ideas students should have already gotten from the text. In summer 2007 we were funded to redesign the course. Our goals were to 1) cut the cost of running the course, and 2) improve student learning. Under our redesign optional study groups were replaced by once a week mandatory break out sessions where students complete activities that have been introduced in lecture. Break out sessions substitute for one hour of lecture, and are run by undergraduate preceptors and graduate teaching assistants (GTAs). During the lecture period, lectures themselves are brief with a large portion of the class devoted to active learning in small groups. Weekly reading quizzes are submitted via the online course management system. Break out sessions allow students to spend more time interacting with their fellow students, undergraduate preceptors, and GTAs. They get one on one help in break out sessions on assignments designed to enhance the lecture material. The active lecture format means less of their time is devoted to listening passively to a lecture, and more time is spent peer learning an interacting with the instructor. Completing quizzes online allows students

  6. SOFT X-RAY FEL BY CASCADING STAGES OF HIGH GAIN HARMONIC GENERATION.

    YU,L.H.

    2003-04-17

    Short wavelength Free-Electron Lasers are perceived as the next generation of synchrotron light sources. In the past decade, significant advances have been made in the theory and technology of high brightness electron beams and single pass FELs. These developments facilitate the construction of practical VUV FELs and make x-ray FELs possible. Self-Amplified Spontaneous Emission (SASE) and High Gain Harmonic Generation (HGHG)[17-19] are the two leading candidates for x-ray FELs. The first lasing of HGHG proof-of-principle experiment succeeded in August, 1999 in Brookhaven National Laboratory. The experimental results agree with the theory prediction. Compared with SASE FEL, the following advantages of HGHG FEL were confirmed; (1) Better longitudinal coherence, and hence, much narrower bandwidth than SASE. (2) More stable central wavelength, (3) More stable output energy. In this introduction, we will first briefly describe the principle of HGHG in Section A. Then in Section B, we give a general description about how to produce soft x-ray by cascading HGHG scheme. In section 2, we give a detailed description of the system design. Then, in section 3, we give a description of an analytical estimate for the HGHG process, and the calculation of the parameters of different parts of the system. The estimate is found to agree with simulation within about a factor 2 for most cases we studied. The stability issue, the sensitivity to parameter variation, the harmonic contents of the final output, and the noise degradation issue of such HGHG scheme are discussed in Section 4. The results are presented in Section 4. Finally, in Section 5, we will give some discussion of the challenges in development of the system. The conclusion is given in Section 6.

  7. Dynamic Sliding Mode Evolution PWM Controller for a Novel High-Gain Interleaved DC-DC Converter in PV System

    Taizhou Bei

    2014-01-01

    Full Text Available Considering the disadvantages of the traditional high-gain DC-DC converter such as big size, high voltage stress of switches, and large input current ripple, a novel high-gain interleaved boost converter with coupled-inductor and switched-capacitor was proposed correspondingly and the operation principle together with the steady-state analysis of this converter was also described. Besides, a new control approach-dynamic sliding mode evolution PWM controller (DSME PWM for the novel topological converter based on both dynamic evolution and sliding mode control was also presented. From the simulation results and experimental validation the proposed converter can fulfill high-gain boost, low ripple of both the input current and the output voltage. Furthermore, MPPT technique can be also achieved in a short time by simulation. The efficiency and stability of the converter proposed in this paper can be improved.

  8. The Effects of Activity and Gain Based Virtual Material on Student's Success, Permanency and Attitudes towards Science Lesson

    Tas, Erol

    2015-01-01

    The main objective of this study is to research the effects of a student gains and activity based virtual material on students' success, permanence and attitudes towards science lesson, developed for science and technology lesson 6th grade "Systems in our body" unit. The study, which had a quasi-experimental design, was conducted with…

  9. Liver Fatty Acid Binding Protein Gene-ablation Exacerbates Weight Gain in High-Fat Fed Female Mice

    McIntosh, Avery L.; Atshaves, Barbara P.; Landrock, Danilo; Landrock, Kerstin K.; Martin, Gregory G.; Storey, Stephen M.; Kier, Ann B.; Schroeder, Friedhelm

    2013-01-01

    Loss of liver fatty acid binding protein (L-FABP) decreases long chain fatty acid uptake and oxidation in primary hepatocytes and in vivo. On this basis, L-FABP gene ablation would potentiate high-fat diet-induced weight gain and weight gain/energy intake. While this was indeed the case when L-FABP null (−/−) mice on the C57BL/6NCr background were pair-fed high fat diet, whether this would also be observed under high-fat diet fed ad libitum was not known. Therefore, this possibility was exami...

  10. The role of diet and physical activity in post-transplant weight gain after renal transplantation

    Zelle, Dorien M.; Kok, Trijntje; Dontje, Manon L.; Danchell, Eva I.; Navis, Gerjan; van Son, Willem J.; Bakker, Stephan J. L.; Corpeleijn, Eva

    2013-01-01

    Background Long-term survival of renal transplant recipients (RTR) has not improved over the past 20yr. The question rises to what extent lifestyle factors play a role in post-transplant weight gain and its associated risks after transplantation. Methods Twenty-six RTR were measured for body weight,

  11. Noticeable positive Doppler effect on optical bistability in an N-type active Raman gain atomic system

    Chang Zeng-Guang; Niu Yue-Ping; Zhang Jing-Tao; Gong Shang-Qing

    2012-01-01

    We theoretically investigate the Doppler effect on optical bistability in an N type active Raman gain atomic system inside an optical ring cavity.It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region,which has been known as the positive Doppler effect on optical bistability.In addition,we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type.

  12. Noticeable positive Doppler effect on optical bistability in an N-type active Raman gain atomic system

    We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region, which has been known as the positive Doppler effect on optical bistability. In addition, we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type

  13. Can physical activity reduce excessive gestational weight gain? Findings from a Chinese urban pregnant women cohort study

    Jiang Hong; Qian Xu; Li Mu; Lynn Henry; Fan Yanyan; Jiang Hongyi; He Fengling; He Gengsheng

    2012-01-01

    Abstract Background Excessive gestational weight gain (GWG) poses negative impact on mothers and their children. It is important to understand the modifiable lifestyle factors associated with excessive GWG during pregnancy to guide future public health practice. Aim To investigate the association between physical activity during pregnancy and GWG of Chinese urban pregnant women. Methods A pregnant women cohort was established between 2005 and 2007 in Changzhou, China. Physical activity levels...

  14. Designing Gain- and Loss-Framed Messages to Increase Physical Activity among University Students Living in two Different Cultures

    Pelin Ozgur Polat

    2015-01-01

    BACKGROUND Widespread evidence indicates that physical activity has positive effects on physical health in long-run. Therefore, adopting exercising habits at early ages is essential for reducing risk of developing chronic diseases. As a result, prevention studies frequently focus on informing young people about possible consequences of engaging or not engaging in physical activity to encourage them to develop a healthy lifestyle. Gain- and loss-framed health messages (Rothman & Salove...

  15. A PMT-like high gain avalanche photodiode based on GaN/AlN periodical stacked structure

    Zheng, Ji-yuan; Yang, Di; Yu, Jia-dong; Meng, Xiao; E, Yan-xiong; Wu, Chao; Hao, Zhi-biao; Sun, Chang-zheng; Xiong, Bing; Luo, Yi; Han, Yan-jian; Wang, Jian; Li, Hong-tao; Brault, Julien; Matta, Samuel; Khalfioui, Mohamed Al; Yan, Jian-chang; Wei, Tong-bo; Zhang, Yun; Wang, Jun-xi

    2016-01-01

    Avalanche photodiode (APD) has been intensively investigated as a promising candidate to replace photomultiplier tubes (PMT) for weak light detection. However, in conventional APDs, a large portion of carrier energy drawn from the electric field is thermalized, and the multiplication efficiencies of electron and hole are low and close. In order to achieve high gain, the device should work under breakdown bias, where carrier multiplication proceeds bi-directionally to form a positive feedback multiplication circle. However, breakdown is hard to control, in practice, APDs should work under Geiger mode as a compromise between sustainable detection and high gain. The complexity of system seriously restricts the application. Here, we demonstrate an avalanche photodiode holding high gain without breakdown, which means no quenching circuit is needed for sustainable detection. The device is based on a GaN/AlN periodically-stacked-structure (PSS), wherein electron holds much higher efficiency than hole to draw energy ...

  16. Risperidone-induced weight gain and reduced locomotor activity in juvenile female rats: The role of histaminergic and NPY pathways.

    Lian, Jiamei; De Santis, Michael; He, Meng; Deng, Chao

    2015-01-01

    Second generation antipsychotic drugs (SGAs) such as risperidone are increasingly prescribed (mostly for off-label use) to children and adolescents for treating various mental disorders. SGAs cause serious weight gain/obesity and other metabolic side-effects. This study aimed to establish an animal model of risperidone-induced weight gain in female juvenile rats, and to investigate the effects of risperidone on the expression of hypothalamic histaminergic H1 receptors (H1R) and neuropeptides, and their association with weight gain. Female Sprague Dawley rats were treated orally with risperidone (0.3mg/kg, 3 times/day) or vehicle (control) starting from postnatal day (PD) 23 (±1 day) for 3 weeks (a period corresponding to the childhood-adolescent period in humans). In the female juvenile rats, risperidone treatment increased food intake and body weight gain, which started to appear after 12 days' treatment. Risperidone also significantly decreased the locomotor activity of the female rats. Consistently, risperidone significantly elevated mRNA expression of hypothalamic H1R, neuropeptide Y (NPY), and agouti-related peptide (AgRP) compared to controls, and H1R and NPY levels were correlated with risperidone enhanced weight gain and food intake in the female juvenile rats. However, risperidone did not affect hypothalamic proopiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) mRNA expression. Therefore, these results suggested that risperidone elevated appetite and body weight gain in juveniles via regulation of the hypothalamic H1R, NPY and AgRP pathways, as well as by reducing activity. PMID:25782398

  17. An ultra-low voltage high gain operational transconductance amplifier for biomedical applications

    Bautista, F.; Martınez, S.O.; Dieck, G.; Rossetto, O.

    2007-01-01

    A novel differential-input single-output Operational Transconductance Amplifier (OTA) is presented in this paper. The topology proposed consists of an input stage based on a folded cascoded amplifier, and an output stage based on a current source amplifier and a bulk-driven current mirror. The simulations show that the amplifier has a 1.94¹W power dissipation, 92dB open-loop DC gain, a unit gain-bandwidth of 390KHz, a low noise between 537Hz to 390KHz and operates at 0.5V rail-to-rail supply ...

  18. UV x-ray free electron lasers through high-gain single pass amplifier: Basic principles and issues

    The author reviews the basic principles of high gain free electron laser amplifier in single pass configuration for generation of intense, tunable radiation for wavelength shorter than 1,000 angstrom. Two schemes are discussed: for wavelength region between 1,000--100 angstrom, the high gain harmonic generation of a coherent input radiation can be used. For x-ray wavelength as short as a few angstrom, the self-amplified spontaneous emission is currently the only known free electron laser scheme. The author also presents a brief introduction of various key issues in realizing these schemes, which will be discussed in detail in other papers in these proceedings

  19. High Dietary Fat Exacerbates Weight Gain and Obesity in Female Liver Fatty Acid Binding Protein Gene-Ablated Mice

    Atshaves, Barbara P.; McIntosh, Avery L.; Storey, Stephen M.; Landrock, Kerstin K.; Kier, Ann B.; Schroeder, Friedhelm

    2009-01-01

    Since liver fatty acid binding protein (L-FABP) facilitates uptake/oxidation of long-chain fatty acids in cultured transfected cells and primary hepatocytes, loss of L-FABP was expected to exacerbate weight gain and/or obesity in response to high dietary fat. Male and female wild-type (WT) and L-FABP gene-ablated mice, pair-fed a defined isocaloric control or high fat diet for 12 weeks, consumed equal amounts of food by weight and kcal. Male WT mice gained weight faster than their female WT c...

  20. Moderate volume of high relative training intensity produces greater strength gains compared with low and high volumes in competitive weightlifters.

    González-Badillo, Juan José; Izquierdo, Mikel; Gorostiaga, Esteban M

    2006-02-01

    The purpose of this study was to examine the effect of 3 volumes of heavy resistance, average relative training intensity (expressed as a percentage of 1 repetition maximum that represented the absolute kilograms lifted divided by the number of repetitions performed) programs on maximal strength (1RM) in Snatch (Sn), Clean & Jerk (C&J), and Squat (Sq). Twenty-nine experienced (>3 years), trained junior weightlifters were randomly assigned into 1 of 3 groups: low-intensity group (LIG; n = 12), moderate-intensity group (MIG; n = 9), and high-intensity group (HIG; n = 8). All subjects trained for 10 weeks, 4-5 days a week, in a periodized routine using the same exercises and training volume (expressed as total number of repetitions performed at intensities equal to or greater than 60% of 1RM), but different programmed total repetitions at intensities of >90-100% of 1RM for the entire 10-week period: LIG (46 repetitions), MIG (93 repetitions), and HIG (184 repetitions). During the training period, MIG and LIG showed a significant increase (p < 0.01-0.05) for C&J (10.5% and 3% for MIG and LIG, respectively) and Sq (9.5% and 5.3% for MIG and LIG, respectively), whereas in HIG the increase took place only in Sq (6.9%, p < 0.05). A calculation of effect sizes revealed greater strength gains in the MIG than in HIG or LIG. There were no significant differences between LIG and HIG training volume-induced strength gains. All the subjects in HIG were unable to fully accomplish the repetitions programmed at relative intensities greater than 90% of 1RM. The present results indicate that short-term resistance training using moderate volumes of high relative intensity tended to produce higher enhancements in weightlifting performance compared with low and high volumes of high relative training intensities of equal total volume in experienced, trained young weightlifters. Therefore, for the present population of weightlifters, it may be beneficial to use the MIG training protocol to

  1. High-temporal contrast using low-gain optical parametric amplification

    Shah, Rahul C [Los Alamos National Laboratory; Johnson, Randall P [Los Alamos National Laboratory; Shimada, Tsutomu [Los Alamos National Laboratory; Flippo, Kirk A [Los Alamos National Laboratory; Fernandez, Juan C [Los Alamos National Laboratory; Hegelich, Bjorn M [Los Alamos National Laboratory

    2008-01-01

    We demonstrate the use of low-gain optical parametric amplification (OPA) as a means of improving temporal contrast to a detection-limited level 10{sup -10}. 250 {mu}J, 500 fs pulses of 1053 nm are frequency doubled and subsequently restored to the original wavelength by OPA with >10% efficiency.

  2. Gain-scheduled Linear Quadratic Control of Wind Turbines Operating at High Wind Speed

    Østergaard, Kasper Zinck; Stoustrup, Jakob; Brath, Per

    then interpolated linearly to get a control law for the entire operating envelope. A nonlinear state estimator is designed as a combination of two unscented Kalman filters and a linear disturbance estimator. The gain-scheduling variable (wind speed) is then calculated from the output of these state...

  3. Transgenic Rescue of Adipocyte Glucose-dependent Insulinotropic Polypeptide Receptor Expression Restores High Fat Diet-induced Body Weight Gain

    Ugleholdt, Randi; Pedersen, Jens; Bassi, Maria Rosaria;

    2011-01-01

    The glucose-dependent insulinotropic polypeptide receptor (GIPr) has been implicated in high fat diet-induced obesity and is proposed as an anti-obesity target despite an uncertainty regarding the mechanism of action. To independently investigate the contribution of the insulinotropic effects and...... the direct effects on adipose tissue, we generated transgenic mice with targeted expression of the human GIPr to white adipose tissue or beta-cells, respectively. These mice were then cross-bred with the GIPr knock-out strain. The central findings of the study are that mice with GIPr expression...... targeted to adipose tissue have a similar high fat diet -induced body weight gain as control mice, significantly greater than the weight gain in mice with a general ablation of the receptor. Surprisingly, this difference was due to an increase in total lean body mass rather than a gain in total fat mass...

  4. Modified unscented Kalman filter using modified filter gain and variance scale factor for highly maneuvering target tracking

    Changyun Liu; Penglang Shui; Gang Wei; Song Li

    2014-01-01

    To improve the low tracking precision caused by lagged filter gain or imprecise state noise when the target highly maneu-vers, a modified unscented Kalman filter algorithm based on the improved filter gain and adaptive scale factor of state noise is pre-sented. In every filter process, the estimated scale factor is used to update the state noise covariance Qk, and the improved filter gain is obtained in the filter process of unscented Kalman filter (UKF) via predicted variance Pk|k-1, which is similar to the standard Kalman filter. Simulation results show that the proposed algorithm provides better accuracy and ability to adapt to the highly maneu-vering target compared with the standard UKF.

  5. High-gain KY(WO4)2:Yb3+ planar waveguide laser at the zero-phonon line

    Geskus, D.; Aravazhi, S.; Wörhoff, K.; Pollnau, M.

    2010-01-01

    When pumping at a short wavelength of 932 nm, the high gain obtained at the 981-nm zero-phonon line of a KY(WO4)2:Gd3+, Lu3+, Yb3+ planar waveguide resulted in efficient laser emission in an open cavity configuration.

  6. High-power gain-switched Tm(3+)-doped fiber laser.

    Tang, Yulong; Xu, Lin; Yang, Yi; Xu, Jianqiu

    2010-10-25

    Gain-switched by a 1.914-µm Tm:YLF crystal laser, a two-stage Tm(3+) fiber laser has been achieved 100-W level ~2-µm pulsed laser output with a slope efficiency of ~52%. With the 6-m length of Tm fiber, the laser wavelength was centered at 2020 nm with a bandwidth of ~25 nm. Based on an acousto-optic switch, the pulse repetition rate can be modulated from 500 Hz to 50 kHz, and the laser pulse width can be tuned between 75 ns and ~1 µs. The maximum pulse energy was over 10 mJ, and the maximum pulse peak power was 138 kW. By using the fiber-coiling-induced mode-filtering effect, laser beam quality of M2 = 1.01 was obtained. Further scaling the pulse energy and average power from such kind of gain-switched fiber lasers was also discussed. PMID:21164635

  7. High Adherence Is Necessary to Realize Health Gains from Water Quality Interventions

    Brown, J.; Clasen, T

    2012-01-01

    BACKGROUND: Safe drinking water is critical for health. Household water treatment (HWT) has been recommended for improving access to potable water where existing sources are unsafe. Reports of low adherence to HWT may limit the usefulness of this approach, however. METHODS AND FINDINGS: We constructed a quantitative microbial risk model to predict gains in health attributable to water quality interventions based on a range of assumptions about pre-treatment water quality; treatment effective...

  8. High-Cost Domestic Joint Ventures and International Competition: Do Domestic Firms Gain?

    Ruth R. Raubitschek; Barbara J. Spencer

    1994-01-01

    This paper develops the idea that when markets are imperfectly competitive, final producers may gain from a joint venture that produces part of their input requirements even though marginal cost exceeds the input's market price. Production by the joint venture lowers the market price of the input and this can raise profits sufficiently from final product sales to make the joint venture worthwhile. Also, use of a joint venture internalizes the positive externality from a lower input price. The...

  9. A High-gain and Low-scattering Waveguide Slot Antenna of Artificial Magnetic Conductor Octagonal Ring Arrangement

    X. Liu

    2016-04-01

    Full Text Available A novel design of high-gain and low-scattering waveguide slot antenna is proposed in this paper. Firstly the scattering pattern of artificial magnetic conductor (AMC composite surface is estimated by array factor analysis method. The comparison between octagonal ring arrangement and chessboard arrangement proves that the former arrangement has the characteristic of diffuseness-like and expands the bandwidth of radar cross section (RCS reduction. Secondly, the metal surface of waveguide slot antenna (WSA is replaced by the octagonal ring arrangement composite surface (ORACS. The gain is improved because of spurious radiation units which are around the slot. At the same time using the phase cancellation principle, a backscatter null achieves RCS reduction in the vertical direction. Experimental results show that the novel antenna after loading with the ORACS, the gain is improved by 5dB; the bandwidth of RCS reduction (reduction greater than 10dB is 5.24-5.92 GHz.

  10. Seasonal Variations of Polarization Diversity Gain in a Vegetated Area considering High Elevation Angles and a Nomadic User

    Milan Kvicera

    2015-01-01

    Full Text Available Seasonal variations of the polarization diversity gain are addressed for a nomadic user in a vegetated area taking high elevation angles and nongeostationary satellites into consideration. Corresponding experimental data were obtained at a frequency of 2.0 GHz at Stromovka Park in Prague, the Czech Republic, within the full in-leaf and out-of-leaf periods of 2013 and 2014, respectively. By detecting copolarized and cross-polarized components of the transmitted left- and right-handed circularly polarized signals, the corresponding diversity gain was obtained for multiple-input single-output (MISO, single-input multiple-output (SIMO, and combined MISO/SIMO cases. It was found that tree defoliation results in a significant decrease of the polarization diversity gain achieved for low time percentages in particular scenarios.

  11. Wideband and flat-gain amplifier based on high concentration erbium-doped fibres in parallel double-pass configuration

    A wideband and flat gain erbium-doped fibre amplifier (EDFA) is demonstrated using a hybrid gain medium of a zirconiabased erbium-doped fibre (Zr-EDF) and a high concentration erbium-doped fibre (EDF). The amplifier has two stages comprising a 2-m-long ZEDF and 9-m-long EDF optimised for C- and L-band operations, respectively, in a double-pass parallel configuration. A chirp fibre Bragg grating (CFBG) is used in both stages to ensure double propagation of the signal and thus to increase the attainable gain in both C- and L-band regions. At an input signal power of 0 dBm, a flat gain of 15 dB is achieved with a gain variation of less than 0.5 dB within a wide wavelength range from 1530 to 1605 nm. The corresponding noise figure varies from 6.2 to 10.8 dB within this wavelength region.

  12. Activities for gaining insight into IASCC and continuous evaluation of in-service inspection data

    The report is a documentation of the important results of various international studies conducted to gain insight into the occurrence, mechanisms, and characteristic features of irradiation-assisted stress corrosion cracking, IASCC, as well as measures preventing IASCC in light water reactors. The major information can be summarised as follows: the number of cases of damage clearly induced by IASCC is low, as compared to the damage induced by intergranular stress corrosion cracking, IGSCC. In fact, recent information from a review of documented stress corrosion cracking damage of BWR type reactor internals reveals that an increasing number of cracks formerly thought to have been caused by IASCC now can be attributed to ICSCC as the most probable cause. Generally speaking, current knowledge of the impact of ionizing radiation on the corrosion resistance of LWR materials is rather insufficient. (orig./CB)

  13. Does Structured Quizzing with Process Specific Feedback Lead to Learning Gains in an Active Learning Geoscience Classroom?

    Palsole, S.; Serpa, L. F.

    2013-12-01

    There is a great realization that efficient teaching in the geosciences has the potential to have far reaching effects in outreach to decision and policy makers (Herbert, 2006; Manduca & Mogk, 2006). This research in turn informs educators that the geosciences by the virtue of their highly integrative nature play an important role in serving as an entry point into STEM disciplines and helping developing a new cadre of geoscientists, scientists and a general population with an understanding of science. Keeping these goals in mind we set to design introductory geoscience courses for non-majors and majors that move away from the traditional lecture models which don't necessarily contribute well to knowledge building and retention ((Handelsman et al., 2007; Hake, 1997) to a blended active learning classroom where basic concepts and didactic information is acquired online via webquests, lecturettes and virtual field trips and the face to face portions of the class are focused on problem solving exercises. The traditional way to ensure that students are prepared for the in-class activity is to have the students take a quiz online to demonstrate basic competency. In the process of redesign, we decided to leverage the technology to build quizzes that are highly structured and map to a process (formation of divergent boundaries for example) or sets of earth processes that we needed the students to know before in-class activities. The quizzes can be taken multiple times and provide process specific feedback, thus serving as a heuristic to the students to ensure they have acquired the necessary competency. The heuristic quizzes were developed and deployed over a year with the student data driving the redesign process to ensure synchronicity. Preliminary data analysis indicates a positive correlation between higher student scores on in-class application exercises and time spent on the process quizzes. An assessment of learning gains also indicate a higher degree of self

  14. Improvement on a 2 × 2 Elements High-Gain Circularly Polarized Antenna Array

    Liu, C; Yan, A; Yu, C.; Xu, T.

    2015-01-01

    A novel antipodal Vivaldi antenna with tapering serrated structure at the edges is proposed. Compared with traditional Vivaldi antennas without serrated structure, the gain of the designed antenna is significantly improved in the desired frequency band (4.5–7.5 GHz). In addition, a 2 × 2 Vivaldi antenna array with an orthorhombic structure is designed and fabricated to achieve a circular polarization (CP) characteristic. With this configuration, the 3 dB axial ratio bandwidth of the array rea...

  15. Characteristics of trap-filled gallium arsenide photoconductive switches used in high gain pulsed power applications

    The electrical properties of semi-insulating (SI) Gallium Arsenide (GaAs) have been investigated for some time, particularly for its application as a substrate in microelectronics. Of late this material has found a variety of applications other than as an isolation region between devices, or the substrate of an active device. High resistivity SI GaAs is increasingly being used in charged particle detectors and photoconductive semiconductor switches (PCSS). PCSS made from these materials operating in both the linear and non-linear modes have applications such as firing sets, as drivers for lasers, and in high impedance, low current Q-switches or Pockels cells. In the non-linear mode, it has also been used in a system to generate Ultra-Wideband (UWB) High Power Microwaves (HPM). The choice of GaAs over silicon offers the advantage that its material properties allow for fast, repetitive switching action. Furthermore photoconductive switches have advantages over conventional switches such as improved jitter, better impedance matching, compact size, and in some cases, lower laser energy requirement for switching action. The rise time of the PCSS is an important parameter that affects the maximum energy transferred to the load and it depends, in addition to other parameters, on the bias or the average field across the switch. High field operation has been an important goal in PCSS research. Due to surface flashover or premature material breakdown at higher voltages, most PCSS, especially those used in high power operation, need to operate well below the inherent breakdown voltage of the material. The lifetime or the total number of switching operations before breakdown, is another important switch parameter that needs to be considered for operation at high bias conditions. A lifetime of ∼ 104 shots has been reported for PCSS's used in UWB-HPM generation [5], while it has exceeded 108 shots for electro-optic drivers. Much effort is currently being channeled in the study

  16. Heuristic use of mental map information gained from behavioural inspection of routines in daily activities (HUMMINGBIRDS)

    HANNES, Els; JANSSENS, Davy; Wets, Geert

    2007-01-01

    This research project aims at identifying the critical spatial factors in an individual’s mental map which influence daily activity travel behaviour in order to improve the agent-based modelling of activity travel behaviour by means of a computational process model. A qualitative travel survey and in depth interviews are used to identify the spatial factors that appear in the destination and travel mode choice heuristics of experts when discussing their activity space. Recorded interviews are...

  17. Determinants of Developmental Gain in Daily Activities in Young Children with Cerebral Palsy.

    Kruijsen-Terpstra, Anne J A; Ketelaar, Marjolijn; Verschuren, Olaf; Smits, Dirk-Wouter; Jongmans, Marian J; Gorter, Jan Willem

    2014-09-18

    ABSTRACT The aim of this study was to examine which child and family characteristics at the child's age of 2 years are determinants of development of self-care and mobility activities over a period of 2 years in young children with cerebral palsy (CP). Longitudinal data of 92 children, representing all levels of the Gross Motor Function Classification System (GMFCS), were analyzed. Children's self-care and mobility activities were assessed with the Functional Skills Scale of the Pediatric Evaluation of Disability Inventory. Development of self-care and mobility activities was related to several child determinants but no family determinants. GMFCS, type of CP, intellectual capacity, and epilepsy were related to the development of self-care and mobility activities, while manual ability and spasticity were related to development of mobility activities. Multivariate analysis indicated that GMFCS and intellectual capacity were the strongest determinants of development of self-care activities, and GMFCS was the strongest determinant of development of mobility activities. The change in self-care and mobility activities was less favorable in severely affected children with severe disability. Knowledge of GMFCS level and intellectual capacity is important in anticipating change over time and goal setting in young children with CP. PMID:25232647

  18. Operation of proportional counters under high gas gain, high working gas pressure in mixed field of radiation

    It was noted that gas gain depends on type of detected radiation and for beta particle is higher by 6–8 % than for X-ray . Over some value of current flowing through the counter (IC—critical current) the reduction in gas gain due to space charge defined by the time of evacuation of positive ions is observed. The value of IC for different counter geometries and different mixture pressures was measured. It limits the rate capability of the detector for fixed gas gain. Over some value of gas gain (AC—critical value of gas gain) non-proportionality due to self inducted space charge effect is observed. The value of AC was measured as a function of working gas pressure for different counter geometries. Measurements were made for gas compositions Ar+20% CO2 and Ar+6.4% CO2+2.5% N2, for mixture pressures from 0.05 to 0.65 MPa and for different counter geometries

  19. Alkali-activated fly ash. Relationship between mechanical strength gains and initial ash chemistry

    Palomo, A.

    2008-09-01

    Full Text Available Alkali-activated fly ash is the primary component of a new generation of high-strength, durable binders with excellent mechanical properties and durability (on occasion bettering traditional Portland cement performance. Moreover, development of these cements may contribute to mitigating CO2 emissions, since the base material is an industrial by-product. The present study was conducted to determine the effect of the composition of the initial materials (SiO2/Al2O3 and Na2O/Al2O3 ratios on the mechanical properties, nature and composition of the reaction products. The results obtained indicate that there is no linear relationship between these ratios and mechanical strength, but rather a series of optimal values above and below which strength declines. In the specific case of the ratios studied in the present paper, these values were: SiO2/Al2O3= 4.0 and Na2O/Al2O3= 1.0 (molar ratios.Las cenizas volantes activadas alcalinamente constituyen la base de una nueva generación de cementos con muy interesantes propiedades mecánicas, adherentes y durables (a veces incluso mejores que las de los cementos Portland tradicionales. Adicionalmente el desarrollo de estos cementos podría contribuir a mitigar las emisiones de CO2 a la atmósfera, ya que el material base de los mismos puede estar formado por subproductos industriales. En la presente investigación se realizó un estudio para determinar la influencia de la composición de los materiales iniciales (ratios SiO2/Al2O3 y Na2O/Al2O3 en las propiedades mecánicas y en la naturaleza y composición de los productos de reacción. Los resultados obtenidos indican que no existe una relación lineal de dichas ratios con las resistencias mecánicas, sino que existen unos valores óptimos, por encima y debajo de los cuales las resistencias mecánicas disminuyen. En el caso concreto de las ratios estudiadas en el presente trabajo estos valores serian: SiO2/Al2O3= 4,0 y Na2O/Al2O3= 1,0 (relaciones molares

  20. High-gain inertial confinement fusion by volume ignition, avoiding the complexities of fusion detonation fronts of spark ignition

    The main approach to Inertial Confinement Fusion (ICF) uses a high-temperature, low-density core and a high-density, low-temperature outer region of the laser- (or ion beam-)compressed deuterium-tritium (D-T) fuel, in order to ignite a fusion detonation wave at the interface. This is an extremely delicate, unstable configuration which is very difficult to achieve, even with a carefully programmed time dependence of the deposition of the driver energy. This approach was devised in order to reach the high gains needed for low-efficiency lasers. Since 1978, several teams have developed an alternative scheme using volume ignition, where a natural and simple adiabatic compression, starting from a low initial temperature of 3 keV or less, is used. The high gains are obtained by self-heating due to the fusion reaction products plus self-absorption of Bremsstrahlung. Fortunately, a strong deviation from LTE occurs at ion temperatures above 100 keV, with much lower electron and even lower radiation temperatures. The authors report here how the gains calculated by different groups are relatively large, and despite detailed differences in the stopping power models, do not differ greatly. The high gain can be explained by introducing an effective value for the density-radius (ρR) product, where the volume ignition process increases the usual value of about 3 g-cm-2 to an effective value of 12 g-cm-2 or more, due to the self-generated additional heating that occurs for beam input energies > MJ and compression over 1,000 times solid state. This result is valid for direct drive as well as for indirect drive

  1. Driving high-gain shock-ignited inertial confinement fusion targets by green laser light

    Standard direct-drive inertial confinement fusion requires UV light irradiation in order to achieve ignition at total laser energy of the order of 1 MJ. The shock-ignition approach opens up the possibility of igniting fusion targets using green light by reducing the implosion velocity and laser-driven ablation pressure. An analytical model is derived, allowing to rescale UV-driven targets to green light. Gain in the range 100–200 is obtained for total laser energy in the range 1.5–3 MJ. With respect to the original UV design, the rescaled targets are less sensitive to irradiation asymmetries and hydrodynamic instabilities, while operating in the same laser-plasma interaction regime.

  2. High gain-production efficiency and large brightness X-UV laser at Palaiseau

    Jaeglé, P.; Carillon, A.; Dhez, P.; Goedtkindt, P.; Jamelot, G.; Klisnick, A.; Rus, B.; Zeitoun, Ph.; Jacquemot, S.; Mazataud, D.; Mens, A.; Chauvineau, J. P.

    1995-05-01

    A large gain has been measured for the J=0-1 line of neonlike Zn at λ=21.2 nm. The time evolutions and the localization of emission zones of the J=0-1 and J=2-1 lines are compared. It is shown that a train of very small prepulses before the main pulse has an important role in the J=0=1 emission. A half-cavity has been successfully used to attain a nearly saturated intensity with a 2 cm long plasma. The X-UV pulse energy is of 400 μJ, the laser power of 5 MW. The driving laser is the 0.4 KJ, 600 ps laser of LULI.

  3. A novel broadband and high-gain microstrip reflectarray antenna with variable polarization

    Zhihang WU; Wenxun ZHANG; Zhenguo LIU; Wei SHEN

    2008-01-01

    This article proposes a new kind of microstrip reflectarray antenna, of which the polarization could be reconfigured among all the polarization states instead of some fixed states in a dual- or multi-polarized antenna. The mechanism for polarized variability is so simple that only mechanical rotation is needed. Theoretical analysis shows that the refected polarization covers all states and that the dual- or multi-layered unit structure sandwiched with air-gaps can broaden the bandwidth efficiently. Moreover, it is demonstrated that adopting more elements can enhance antenna gain. With these advanta-geous features, this kind of antenna has the potential significance for engineering applications in radar, com-munication, etc. In this article, a complete theoretical analysis as well as a specific design sample is given to verify this method.

  4. High temperature and wavelength dependence of avalanche gain of AlAsSb avalanche photodiodes.

    Sandall, Ian C; Xie, Shiyu; Xie, Jingjing; Tan, Chee Hing

    2011-11-01

    The evolution of the dark currents and breakdown at elevated temperatures of up to 450  K are studied using thin AlAsSb avalanche regions. While the dark currents increase rapidly as the temperature is increased, the avalanche gain is shown to only have a weak temperature dependence. Temperature coefficients of breakdown voltage of 0.93 and 1.93  mV/K were obtained from the diodes of 80 and 230  nm avalanche regions (i-regions), respectively. These values are significantly lower than for other available avalanche materials at these temperatures. The wavelength dependence of multiplication characteristics of AlAsSb p-i-n diodes has also been investigated, and it was found that the ionization coefficients for electrons and holes are comparable within the electric field and wavelength ranges measured. PMID:22048393

  5. A multifunctional switched-capacitor programmable gain amplifier for high-definition video analog front-ends

    A multifunctional programmable gain amplifier (PGA) that provides gain and offset adjusting abilities for high-definition video analog front-ends (AFE) is presented. With a switched-capacitor structure, the PGA also acts as a sample and holder of the analog-to-digital converter (ADC) in the AFE to reduce the power consumption and chip area of the whole AFE. Furthermore, the PGA converts the single-ended video signal into differential signal for the following ADC to reject common-mode noise and interferences. The 9-bit digital-to-analog converter (DAC) for gain and offset adjusting is embedded into the switched capacitor networks of the PGA. A video AFE integrated circuit based on the proposed PGA is fabricated in a 0.18-μm process. Simulation and measurement results show that the PGA achieves a gain control range of 0.90 to 2.34 and an offset control range of −220 to 220 mV while consuming 10.1 mA from a 1.8 V power supply. (paper)

  6. A multifunctional switched-capacitor programmable gain amplifier for high-definition video analog front-ends

    Hong, Zhang; Jie, Zhang; Mudan, Zhang; Xue, Li; Jun, Cheng

    2015-03-01

    A multifunctional programmable gain amplifier (PGA) that provides gain and offset adjusting abilities for high-definition video analog front-ends (AFE) is presented. With a switched-capacitor structure, the PGA also acts as a sample and holder of the analog-to-digital converter (ADC) in the AFE to reduce the power consumption and chip area of the whole AFE. Furthermore, the PGA converts the single-ended video signal into differential signal for the following ADC to reject common-mode noise and interferences. The 9-bit digital-to-analog converter (DAC) for gain and offset adjusting is embedded into the switched capacitor networks of the PGA. A video AFE integrated circuit based on the proposed PGA is fabricated in a 0.18-μm process. Simulation and measurement results show that the PGA achieves a gain control range of 0.90 to 2.34 and an offset control range of -220 to 220 mV while consuming 10.1 mA from a 1.8 V power supply. Project supported by the National Natural Science Foundation of China (No. 61106027), and the Science and Technology Project of Shanxi Province (No. 2014K05-14).

  7. High magnetic shear gain in a liquid sodium stable couette flow experiment A prelude to an alpha - omega dynamo

    Colgate, Stirling [Los Alamos National Laboratory; Li, Jui [Los Alamos National Laboratory; Finn, John [Los Alamos National Laboratory; Pariev, Vladimir [Los Alamos National Laboratory; Beckley, Howard [NM INSTIT. OF MINING AND TECH; Si, Jiahe [NM INSTIT. OF MINING AND TECH.; Martinic, Joe [NM INSTIT. OF MINING AND TECH.; Westpfahl, David [NM INSTIT. OF TECH.; Slutz, James [NM INSTIT. OF MINING AND TECH.; Westrom, Zeb [NM INSTIT. OF TECH.; Klein, Brianna [NM INSTIT. OF MINING AND TECH.

    2010-11-08

    The {Omega}-phase of the liquid sodium {alpha}-{Omega} dynamo experiment at NMIMT in cooperation with LANL has successfully demonstrated the production of a high toroidal field, B{sub {phi}} {approx_equal} 8 x B{sub r} from the radial component of an applied poloidal magnetic field, B{sub r}. This enhanced toroidal field is produced by rotational shear in stable Couette Row within liquid sodium at Rm {approx_equal} 120. The small turbulence in stable Taylor-Couette Row is caused by Ekman Row where ({delta}v/v){sup 2} {approx} 10{sup -3}. This high {Omega}-gain in low turbulence flow contrasts with a smaller {Omega}-gain in higher turbulence, Helmholtz-unstable shear flows. This result supports the ansatz that large scale astrophysical magnetic fields are created within semi-coherent large scale motions in which turbulence plays a diffusive role that enables magnetic flux linkage.

  8. Interplay of the Chirps and Chirped Pulse Compression in a High-gain Seeded Free-electron Laser

    Wu, Juhao; /SLAC; Murphy, J.B.; /LBNL, ALS; Emma, P.J.; /SLAC; Wang, X.J.; Watanabe, T.; /LBNL, ALS; Zhong, Xinming; /Beijing Normal U.

    2007-01-03

    In a seeded high-gain Free-electron Laser (FEL), where a coherent laser pulse interacts with an ultra-relativistic electron beam, the seed laser pulse can be frequency chirped, and the electron beam can be energy chirped. Besides these two chirps, the FEL interaction introduces an intrinsic frequency chirp in the FEL even if the above mentioned two chirps are absent. In this paper we examine the interplay of these three chirps. The problem is formulated as an initial value problem, and solved via a Green function approach. Besides the chirp evolution, we also give analytical expressions for the pulse duration and bandwidth of the FEL, which remains fully longitudinally coherent in the high gain exponential growth regime. Because the chirps are normally introduced for a final compression of the FEL pulse, some conceptual issues are discussed. We show that in order to get a short pulse duration, an energy chirp in the electron beam is necessary.

  9. General and persistent effects of high-intensity sweeteners on body weight gain and caloric compensation in rats

    Swithers, Susan E.; Baker, Chelsea R.; Davidson, T.L.

    2009-01-01

    In four experiments, we assessed the generality of previous findings (Swithers & Davidson, 2008) that increased caloric intake, body weight gain, and reduced caloric compensation are exhibited by rats that consume a diet containing a nonnutritive, high intensity sweetener. In this earlier work, rats consumed a diet in which saccharin was mixed in low-fat yogurt, and animals were provided with a fixed amount of the yogurt. The present experiments showed that the effects of saccharin on energy ...

  10. Seasonal Variations of Polarization Diversity Gain in a Vegetated Area considering High Elevation Angles and a Nomadic User

    Milan Kvicera; Pavel Pechac

    2015-01-01

    Seasonal variations of the polarization diversity gain are addressed for a nomadic user in a vegetated area taking high elevation angles and nongeostationary satellites into consideration. Corresponding experimental data were obtained at a frequency of 2.0 GHz at Stromovka Park in Prague, the Czech Republic, within the full in-leaf and out-of-leaf periods of 2013 and 2014, respectively. By detecting copolarized and cross-polarized components of the transmitted left- and right-handed circularl...

  11. Improving of Multivariable PI Controller with a High Gain Structure for an Irregular System by Genetic Algorithm

    Seyyed Abed Hosseini

    2015-07-01

    Full Text Available This paper describes an optimal design for multivariable PI controller with a high gain structure for an irregular system by genetic algorithm. PI controllers with a high gain structure leads to the asymptotic decomposition of the fast and slow modes in the closed loop system that have unique characteristics. The slow modes are asymptotically uncontrollable and unobservable; therefore, they have not role in input and output behavior. The closed-loop response is affected only from rapid poles; therefore, the system response will have quick behavior. An essential requirement of this design is that the first Markov parameter of multivariable system (the matrix product CB must have full rank. If the CB matrix is not full rank, the measurement matrix (M is used with internal feedback. In this structure, the measurement matrix is chosen using genetic algorithm in order to reach the stable closed-loop system and minimize interference between outputs. The research is implemented on the two kind of different systems. The results show that the response time of PI controller with a high gain structure by genetic algorithms has good behavior in comparison with other methods.

  12. Determinants of developmental gain in daily activities in young children with cerebral palsy

    Kruijsen-Terpstra, Anne JA; Ketelaar, Marjolijn; Verschuren, Olaf; Smits, Dirk-Wouter; Jongmans, Marian J; Gorter, Jan Willem

    2015-01-01

    The aim of this study was to examine which child and family characteristics at the child's age of 2 years are determinants of development of self-care and mobility activities over a period of 2 years in young children with cerebral palsy (CP). Longitudinal data of 92 children, representing all level

  13. Determinants of Developmental Gain in Daily Activities in Young Children with Cerebral Palsy

    Kruijsen-Terpstra, Anne J A; Ketelaar, Marjolijn; Verschuren, Olaf; Smits, Dirk-Wouter; Jongmans, Marian J; Gorter, Jan Willem

    2015-01-01

    The aim of this study was to examine which child and family characteristics at the child's age of 2 years are determinants of development of self-care and mobility activities over a period of 2 years in young children with cerebral palsy (CP). Longitudinal data of 92 children, representing all level

  14. The Design of High-Q Sallen-Key Biquads with Unity-Gain Buffer Amplifiers

    Gaunholt, Hans; Guldbrandsen, Birthe

    1997-01-01

    In the design of active biquads with negative feedback frequently referred to as Sallen-Key networks the assumption of a low quality- or Q-factor is recommended in order to keep the active sensitivities at a reasonable low value. In this paper it will be shown that it is possible to design and to...

  15. Overexpression of Jazf1 reduces body weight gain and regulates lipid metabolism in high fat diet

    Highlights: • The expression of Jazf1 in the liver suppressed lipid accumulation. • Jazf1 significantly increases transcription of fatty acid synthase. • Jazf1 plays a critical role in the regulation of energy and lipid homeostasis. • Jazf1 associates the development of metabolic disorder. • Jazf1 may provide a new therapeutic target in the management of metabolic disorder. - Abstract: Jazf1 is a 27 kDa nuclear protein containing three putative zinc finger motifs that is associated with diabetes mellitus and prostate cancer; however, little is known about the role that this gene plays in regulation of metabolism. Recent evidence indicates that Jazf1 transcription factors bind to the nuclear orphan receptor TR4. This receptor regulates PEPCK, the key enzyme involved in gluconeogenesis. To elucidate Jazf1’s role in metabolism, we fed a 60% fat diet for up to 15 weeks. In Jazf1 overexpression mice, weight gain was found to be significantly decreased. The expression of Jazf1 in the liver also suppressed lipid accumulation and decreased droplet size. These results suggest that Jazf1 plays a critical role in the regulation of lipid homeostasis. Finally, Jazf1 may provide a new therapeutic target in the management of obesity and diabetes

  16. A megajoule class krypton fluoride amplifier for single shot, high gain ICF application

    A design study is underway to define the optimal architecture for a KrF laser system which will deliver 10 MJ of 248-nm light to an ICF target. The authors present one approach which incorporates final power amplifiers in the megajoule class, achieving 10 MJ with only four final amplifiers. Each double-pass laser amplifier employs two-sided electron-beam pumping of the laser gas medium. Analysis of the design is based on a Monte-Carlo electron-beam deposition code, a one-dimensional, time-dependent kinetics code, and pulsed power circuit modeling. Linear dimensions of the amplifier's extracted gain volume are 6.25 m in height and length and 5.12 m in width. Each amplifier handles 160 angularly multiplexed laser channels. The one-amagat, krypton-rich laser medium is e-beam pumped at 60 kW cm/sup -3/ (4 MA at 3.3 MV) over the 2-microsecond duration of the laser beam pulse train

  17. A megajoule class krypton fluoride amplifier for single shot, high gain ICF application

    A design study is underway to define the optimal architecture for a KrF laser system which will deliver 10 MJ of 248-nm light to an ICF target. We present one approach which incorporates final power amplifiers in the megajoule class, achieving 10 MJ with four final amplifiers. Each double-pass laser amplifier employs two-sided electron-beam pumping of the laser gas medium. Details of the design are based on a Monte-Carlo electron-beam deposition code, a one-dimensional, time-dependent kinetics code, and pulsed power circuit modeling. Linear dimensions of the amplifier's extracted gain volume are 6.25 m in height and length and 5.12 m in width. Each amplifier handles 160 angularly multiplexed laser channels. The one-amagat, krypton-rich laser medium is e-beam pumped at 60-kW cm/sup /minus/3/ (4-MA at3.3-MV) over the 2-microsecond duration of the laser beam pulse train. 5 refs., 4 figs

  18. Overexpression of Jazf1 reduces body weight gain and regulates lipid metabolism in high fat diet

    Jang, Woo Young; Bae, Ki Beom; Kim, Sung Hyun; Yu, Dong Hun; Kim, Hei Jung; Ji, Young Rae; Park, Seo Jin; Park, Si Jun; Kang, Min-Cheol; Jeong, Ja In [School of Life Science and Biotechnology, Kyungpook National University, 1370 Sankyuk-dong, Buk-ku, Daegu 702-701 (Korea, Republic of); Park, Sang-Joon [College of Veterinary Medicine, Kyungpook National University, 1370 Sankyuk-dong, Buk-ku, Daegu 702-701 (Korea, Republic of); Lee, Sang Gyu [School of Life Science and Biotechnology, Kyungpook National University, 1370 Sankyuk-dong, Buk-ku, Daegu 702-701 (Korea, Republic of); Lee, Inkyu [School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 700-842 (Korea, Republic of); Kim, Myoung Ok [School of Animal BT Sciences, Sangju Campus, Kyungpook National University, 386 Gajang-dong, Sangju, Gyeongsangbuk-do 742-211 (Korea, Republic of); Yoon, Duhak, E-mail: dhyoon@knu.ac.kr [School of Animal BT Sciences, Sangju Campus, Kyungpook National University, 386 Gajang-dong, Sangju, Gyeongsangbuk-do 742-211 (Korea, Republic of); Ryoo, Zae Young, E-mail: jaewoong64@hanmail.net [School of Life Science and Biotechnology, Kyungpook National University, 1370 Sankyuk-dong, Buk-ku, Daegu 702-701 (Korea, Republic of)

    2014-02-14

    Highlights: • The expression of Jazf1 in the liver suppressed lipid accumulation. • Jazf1 significantly increases transcription of fatty acid synthase. • Jazf1 plays a critical role in the regulation of energy and lipid homeostasis. • Jazf1 associates the development of metabolic disorder. • Jazf1 may provide a new therapeutic target in the management of metabolic disorder. - Abstract: Jazf1 is a 27 kDa nuclear protein containing three putative zinc finger motifs that is associated with diabetes mellitus and prostate cancer; however, little is known about the role that this gene plays in regulation of metabolism. Recent evidence indicates that Jazf1 transcription factors bind to the nuclear orphan receptor TR4. This receptor regulates PEPCK, the key enzyme involved in gluconeogenesis. To elucidate Jazf1’s role in metabolism, we fed a 60% fat diet for up to 15 weeks. In Jazf1 overexpression mice, weight gain was found to be significantly decreased. The expression of Jazf1 in the liver also suppressed lipid accumulation and decreased droplet size. These results suggest that Jazf1 plays a critical role in the regulation of lipid homeostasis. Finally, Jazf1 may provide a new therapeutic target in the management of obesity and diabetes.

  19. Regulation of Nucleotide Metabolism by Mutant p53 Contributes to its Gain-of-Function Activities

    Kollareddy, Madhusudhan; Dimitrova, Elizabeth; Vallabhaneni, Krishna C.; Chan, Adriano; Le, Thuc; Chauhan, Krishna M.; Zunamys I. Carrero; Ramakrishnan, Gopalakrishnan; Watabe, Kounosuke; Haupt, Ygal; Haupt, Sue; Pochampally, Radhika; Boss, Gerard R.; Romero, Damian G.; Radu, Caius G.

    2015-01-01

    SUMMARY Mutant p53 (mtp53) is an oncogene that drives cancer cell proliferation. Here we report that mtp53 associates with the promoters of numerous nucleotide metabolism genes (NMG). Mtp53 knockdown reduces NMG expression and substantially depletes nucleotide pools, which attenuates GTP dependent protein (GTPase) activity and cell invasion. Addition of exogenous guanosine or GTP restores the invasiveness of mtp53 knockdown cells, suggesting that mtp53 promotes invasion by increasing GTP. Add...

  20. The Development of a Digital Marketing Strategy to Gain Active Mobile Game Users in Japan

    Rönkkö, Makiyo

    2014-01-01

    Japan is the world’s biggest spender on mobile apps. This makes it an attractive market, but entering the Japan market is very difficult for Finnish mobile software developers. The goal of this thesis is to identify possible constraints that limit mobile game companies in the Japanese market, and analyze the means of increasing brand awareness and acquiring active game players. The focus is on finding the key elements required for building a digital marketing strategy targeted towards Japanes...

  1. Reduced sympathetic nervous activity. A potential mechanism predisposing to body weight gain.

    Spraul, M.; Ravussin, E.; Fontvieille, A M; Rising, R; Larson, D. E.; Anderson, E. A.

    1993-01-01

    The sympathetic nervous system is recognized to play a role in the etiology of animal and possibly human obesity through its impact on energy expenditure and/or food intake. We, therefore, measured fasting muscle sympathetic nerve activity (MSNA) in the peroneal nerve and its relationship with energy expenditure and body composition in 25 relatively lean Pima Indian males (means +/- SD; 26 +/- 6 yr, 82 +/- 19 kg, 28 +/- 10% body fat) and 19 Caucasian males (29 +/- 5 yr, 81 +/- 13 kg, 24 +/- 9...

  2. High Gain Multiband Loaded Inverted-F Antennas for Mobile WiMAX, Wi-Fi, Bluetooth and WLAN Operation

    Debabrata Kumar Karmokar, Khaled Mahbub Morshed, Abu Md. Numan-Al-Mobin & A. N. M. Enamul Kabir

    2010-08-01

    Full Text Available Multiband loaded inverted-F antennas (LIFA’s suitable to be applied in aportable device as an internal antenna having high gain property for mobileWiMAX, Wi-Fi, Bluetooth and WLAN operation are presented. The proposedantennas are directly feed by 50 Ω coaxial connector. The antenna armseffectively control the excited resonant modes for the required operation. Totalareas occupied by the antennas are 24 × 37 and 29 × 37 mm2 in case of slightlyloaded IFA (SLIFA and moderately loaded IFA (MLIFA respectively. Theantennas contain an incredibly high peak gains of 8.31, 8.88 and 6.32 dBi and8.48, 8.67 and 6.89 dBi for 2.3 GHz mobile WiMAX, 2.4 GHz WLAN/Bluetoothand 5.8 GHz Wi-Fi operation for SLIFA and MLIFA respectively, with less than0.84 and 1.8 dBi gain variation at lower and upper operating band within the 10dB return loss bandwidth. In addition, the antennas have achievable bandwidth,return loss and radiation characteristics.

  3. High-gain amplification in Yb:CaF2 crystals pumped by a high-brightness Yb-doped 976 nm fiber laser

    We report on high single-pass gain in Yb:CaF2 crystal longitudinally pumped with a 40 W high-brightness fiber laser source based on an ytterbium-doped ultra-large core photonic crystal rod-type fiber operating at 976 nm. A single-pass small-signal gain of 3.2 has been achieved in a 6 % Yb-doped 10-mm-long CaF2 crystal at room temperature, outperforming any CW-diode-pumped scheme and paving the way towards very promising innovative lasers and amplifiers schemes merging the Yb-doped solid state and fiber technologies. (authors)

  4. Modified High Gain APDs for Multi-beam Ladar Instrumentation Project

    National Aeronautics and Space Administration — In this effort, Radiation Monitoring Devices, Inc (RMD) addresses NASA's request for sensitive, high quantum efficiency (QE) optical detectors for space- and...

  5. Replacing Non-Active Video Gaming by Active Video Gaming to Prevent Excessive Weight Gain in Adolescents

    Monique Simons; Johannes Brug; Mai J M Chinapaw; Michiel de Boer; Jaap Seidell; Emely de Vet

    2015-01-01

    OBJECTIVE: The aim of the current study was to evaluate the effects of and adherence to an active video game promotion intervention on anthropometrics, sedentary screen time and consumption of sugar-sweetened beverages and snacks among non-active video gaming adolescents who primarily were of healthy weight. METHODS: We assigned 270 gaming (i.e. ≥2 hours/week non-active video game time) adolescents randomly to an intervention group (n = 140) (receiving active video games and encouragement to ...

  6. Analog time-reversed ultrasonically encoded (TRUE) optical focusing inside scattering media with high power gain (Conference Presentation)

    Ma, Cheng; Xu, Xiao; Wang, Lihong V.

    2016-03-01

    Focusing light deep inside scattering media plays a key role in such biomedical applications as high resolution optical imaging, control, and therapy. In recent years, wavefront shaping technologies have come a long way in controlling light propagation in complex media. A prominent example is time-reversed ultrasonically encoded (TRUE) focusing, which allows noninvasive introduction of "guide stars" inside biological tissue to guide light focusing. By measuring the optical wavefront emanating from an ultrasound focus created at the target location, TRUE determines the desired wavefront non-iteratively, and achieves focusing at the target position via a subsequent optical time reversal. Compared to digital counterparts that employ slow electronic spatial light modulators and cameras, analog TRUE focusing relies on nonlinear photorefractive crystals that inherently accommodate more spatial modes and eliminate the troublesome alignment and data transfer required by digital approaches. However, analog TRUE focusing suffers from its small gain, defined as the energy or power ratio between the focusing and probing beams in the focal volume. Here, by implementing a modified analog TRUE focusing scheme that squeezes the duration of the time-reversed photon packet below the carrier-recombination-limited hologram decay time of the crystal, we demonstrated a photon flux amplification much greater than unity at a preset focal voxel in between two scattering layers. Although the energy gain was still below unity, the unprecedented power gain will nevertheless benefit new biomedical applications.

  7. Toward the realization of erbium-doped GaN bulk crystals as a gain medium for high energy lasers

    Sun, Z. Y.; Li, J.; Zhao, W. P.; Lin, J. Y.; Jiang, H. X.

    2016-08-01

    Er-doped GaN (Er:GaN) is a promising candidate as a gain medium for solid-state high energy lasers (HELs) at the technologically important and eye-safe 1.54 μm wavelength window, as GaN has superior thermal properties over traditional laser gain materials such as Nd:YAG. However, the attainment of wafer-scale Er:GaN bulk or quasi-bulk crystals is a prerequisite to realize the full potential of Er:GaN as a gain medium for HELs. We report the realization of freestanding Er:GaN wafers of 2-in. in diameter with a thickness on the millimeter scale. These freestanding wafers were obtained via growth by hydride vapor phase epitaxy in conjunction with a laser-lift-off process. An Er doping level of 1.4 × 1020 atoms/cm3 has been confirmed by secondary ion mass spectrometry measurements. The freestanding Er:GaN wafers exhibit strong photoluminescent emission at 1.54 μm with its emission intensity increasing dramatically with wafer thickness under 980 nm resonant excitation. A low thermal quenching of 10% was measured for the 1.54 μm emission intensity between 10 K and 300 K. This work represents a significant step in providing a practical approach for producing Er:GaN materials with sufficient thicknesses and dimensions to enable the design of gain media in various geometries, allowing for the production of HELs with improved lasing efficiency, atmosphere transmission, and eye-safety.

  8. Fructose-induced leptin resistance exacerbates weight gain in response to subsequent high-fat feeding

    Shapiro, Alexandra; Mu, Wei; Roncal, Carlos; Cheng, Kit-Yan; Richard J Johnson; Scarpace, Philip J.

    2008-01-01

    It has been suggested that increased fructose intake is associated with obesity. We hypothesized that chronic fructose consumption causes leptin resistance, which subsequently may promote the development of obesity in response to a high-fat diet. Sprague-Dawley rats were fed a fructose-free control or 60% fructose diet for 6 mo and then tested for leptin resistance. Half of the rats in each group were then switched to high-fat diet for 2 wk, while the other half continued on their respective ...

  9. Whey Protein Reduces Early Life Weight Gain in Mice Fed a High-Fat Diet

    Tranberg, Britt; Hellgren, Lars; Lykkesfeldt, Jens; Sejrsen, Kristen; Jeamet, Aymeric; Rune, Ida; Ellekilde, Merete; Nielsen, Dennis Sandris; Hansen, Axel Kornerup

    2013-01-01

    An increasing number of studies indicate that dairy products, including whey protein, alleviate several disorders of the metabolic syndrome. Here, we investigated the effects of whey protein isolate (whey) in mice fed a high-fat diet hypothesising that the metabolic effects of whey would be associated with changes in the gut microbiota composition. Five-week-old male C57BL/6 mice were fed a high-fat diet ad libitum for 14 weeks with the protein source being either whey or casein. Faeces were ...

  10. Whey protein reduces early life weight gain in mice fed a high-fat diet.

    Britt Tranberg; Hellgren, Lars I; Jens Lykkesfeldt; Kristen Sejrsen; Aymeric Jeamet; Ida Rune; Merete Ellekilde; Nielsen, Dennis S.; Axel Kornerup Hansen

    2013-01-01

    An increasing number of studies indicate that dairy products, including whey protein, alleviate several disorders of the metabolic syndrome. Here, we investigated the effects of whey protein isolate (whey) in mice fed a high-fat diet hypothesising that the metabolic effects of whey would be associated with changes in the gut microbiota composition. Five-week-old male C57BL/6 mice were fed a high-fat diet ad libitum for 14 weeks with the protein source being either whey or casein. Faeces were ...

  11. Insights Gained from Modeling High-Grade Glioma in the Mouse

    Rankin, Sherri L; Zhu, Guo; Baker, Suzanne J.

    2012-01-01

    High grade gliomas (HGG) are devastating primary brain tumors with universally poor prognoses. Advances toward effective treatments require improved understanding of pathogenesis and relevant model systems for preclinical testing. Mouse models for HGG provide physiologically relevant experimental systems for analysis of HGG pathogenesis. There are advantages and disadvantages to the different methodologies used to generate such models, including implantation, genetic engineering or somatic ge...

  12. Detailed theoretical and experimental investigation of high-gain erbium-doped fiber amplifier

    Pedersen, Bo; Dybdal, Kristen; Dam-Hansen, Carsten;

    1990-01-01

    A full-scale numerical model for the erbium-doped fiber amplifier has been developed that incorporates realistic index and erbium-concentration profiles as well as the spectral distribution of amplified spontaneous emission (ASE). The high accuracy of the model is demonstrated by comparison with a...

  13. Energy gain and spectral tailoring of ion beams using ultra-high intensity laser beams

    Prasad, Rajendra; Swantusch, Marco; Cerchez, Mirela; Spickermann, Sven; Auorand, Bastian; Wowra, Thomas; Boeker, Juergen; Willi, Oswald

    2015-11-01

    The field of laser driven ion acceleration over the past decade has produced a huge amount of research. Nowadays, several multi-beam facilities with high rep rate system, e.g. ELI, are being developed across the world for different kinds of experiments. The study of interaction dynamics of multiple beams possessing ultra-high intensity and ultra-short pulse duration is of vital importance. Here, we present the first experimental results on ion acceleration using two ultra-high intensity beams. Thanks to the unique capability of Arcturus laser at HHU Düsseldorf, two almost identical, independent beams in laser parameters such as intensity (>1020 W/cm2), pulse duration (30 fs) and contrast (>1010), could be accessed. Both beams are focused onto a 5 μm thin Ti target. While ensuring spatial overlap of the two beams, at relative temporal delay of ~ 50 ps (optimum delay), the proton and carbon ion energies were enhanced by factor of 1.5. Moreover, strong modulation in C4+ions near the high energy cut-off is observed later than the optimum delay for the proton enhancement. This offers controlled tailoring of the spectral content of heavy ions.

  14. Highly Sensitive, Encapsulated MoS2 Photodetector with Gate Controllable Gain and Speed.

    Kufer, Dominik; Konstantatos, Gerasimos

    2015-11-11

    Semiconducting, two-dimensional molybdenum disulfide (MoS2) is considered a promising new material for highly sensitive photodetection, because of its atomically thin profile and favorable bandgap. However, reported photodetectors to date show strong variation in performance due to the detrimental and uncontrollable effects of environmental adsorbates on devices due to large surface to volume ratio. Here, we report on highly stable and high-performance monolayer and bilayer MoS2 photodetectors encapsulated with atomic layer deposited hafnium oxide. The protected devices show enhanced electronic properties by isolating them from the ambience as strong n-type doping, vanishing hysteresis, and reduced device resistance. By controlling the gate voltage the responsivity and temporal response can be tuned by several orders of magnitude with R ∼ 10-10(4) A/W and t ∼ 10 ms to 10 s. At strong negative gate voltage, the detector is operated at higher speed and simultaneously exhibits a low-bound, record sensitivity of D* ≥ 7.7 × 10(11) Jones. Our results lead the way for future application of ultrathin, flexible, and high-performance MoS2 detectors and prompt for further investigation in encapsulated transition metal dichalcogenide optoelectronics. PMID:26501356

  15. Output-feedback load-following control of nuclear reactors based on a dissipative high gain filter

    Highlights: ► The separation principle for the dissipative high gain filter (DHGF) is proved. ► The dynamic output feedback power control based on the DHGF is given for a nuclear reactor. ► This controller gurantees the globally asymptotic closed-loop stability. ► Numerical simulation show the feasibility of this power-level controller. - Abstract: Due to the existing serious climate and environment problems caused by burning fossil fuels, nuclear energy is now under rapid development. It is clear that power-level control technique for nuclear reactors is significant for not only regular operation but also vital safety issues. Nowadays, most of the existing nuclear power plants are regulated by the conventional control system. However, the development in computer technology, information processing, and control theory in the past decades allow the applications of advanced controllers with higher performance. In this paper, the separation principle for the recently established dissipative high gain filter (DHGF) is presented, which guarantees the closed-loop stability of the system interconnected with a state-feedback controller and the DHGF. Moreover, the feasibility of applying the DHGF to the load-following control of nuclear reactors is verified. Finally, the DHGF with a well designed state-feedback power-level controller has been successfully applied to realize the load-following control for a nuclear heating reactor (NHR). Numerical simulation results show the high performance of the DHGF and the feasibility of the DHGF-based dynamic output feedback controller, and influence of the observer gain to the control and observation performance is also analyzed.

  16. Replacing non-active video gaming by active video gaming to prevent excessive weight gain in adolescents

    Simons, M.; Brug, J.; Chinapaw, M.J.M.; Boer, M. de; Seidell, J.; Vet, E. de

    2015-01-01

    Objective: The aim of the current study was to evaluate the effects of and adherence to an active video game promotion intervention on anthropometrics, sedentary screen time and consumption of sugar-sweetened beverages and snacks among non-active video gaming adolescents who primarily were of health

  17. Replacing Non-Active Video Gaming by Active Video Gaming to Prevent Excessive Weight Gain in Adolescents

    Simons, Monique; Brug, Johannes; Chinapaw, Mai J M; de Boer, Michiel; Seidell, Jaap; de Vet, Emely

    2015-01-01

    OBJECTIVE: The aim of the current study was to evaluate the effects of and adherence to an active video game promotion intervention on anthropometrics, sedentary screen time and consumption of sugar-sweetened beverages and snacks among non-active video gaming adolescents who primarily were of health

  18. Replacing Non-Active Video Gaming by Active Video Gaming to Prevent Excessive Weight Gain in Adolescents

    Simons, M.; Brug, J.; Chinapaw, M.J.M.; Boer, de M.; Seidell, J.; Vet, de E.

    2015-01-01

    Objective - The aim of the current study was to evaluate the effects of and adherence to an active video game promotion intervention on anthropometrics, sedentary screen time and consumption of sugar-sweetened beverages and snacks among non-active video gaming adolescents who primarily were of healt

  19. Design of cascading two stages of high gain harmonic generation scheme based on Shanghai deep ultraviolet free electron laser

    DENG Hai-Xiao; DAI Zhi-Min

    2008-01-01

    Cascading stages of high gain harmonic generation free electron laser (FEL) seem to be a feasible way to generate short wavelength radiation. With help of the analytical estimates, we design a two-stage cascading scheme to achieve 131 nm DUV radiation on the basis of the Shanghai deep ultraviolet free electron laser test facility. Detailed studies on the FEL performance, the stability and the sensitivity of the output power to parameter variation have been achieved by GENESIS1.3, and design of the lattice structure is presented.

  20. High-gain adaptive regulator for a string equation with uncertain harmonic disturbance under boundary output feedback control

    Baozhu GUO; Wei GUO

    2003-01-01

    This paper considers the boundary stabilization and parameter estimation of a one-dimensional wave equation in the case when one end is fixed and control and harmonic disturbance with uncertain amplitude are input at another end. A high-gain adaptive regulator is designed in terms of measured collocated end velocity. The existence and uniqueness of the classical solution of the closed-loop system is proven. It is shown that the state of the system approaches the standstill as time goes to infitv and meanwhile, the estimated parameter converges to the unknown parameter.

  1. Statistical properties of radiation power levels from a high-gain free-electron laser at and beyond saturation

    We investigate the statistical properties (e.g., shot-to-shot power fluctuations) of the radiation from a high-gain free-electron laser (FEL) operating in the nonlinear regime. We consider the case of an FEL amplifier reaching saturation whose shot-to-shot fluctuations in input radiation power follow a gamma distribution. We analyze the corresponding output power fluctuations at and beyond first saturation, including beam energy spread effects, and find that there are well-characterized values of undulator length for which the fluctuation level reaches a minimum

  2. Simplification of Sun Tracking Mode to Gain High Concentration Solar Energy

    Omar Aliman

    2007-01-01

    Full Text Available Power conversion from solar thermal energy to electrical energy is still very cost-intensive. Serious effort has to be given in the development of the concentrator or heliostat structure expenditure which contributing the most expensive component in a central receiver solar power plant. With current development to find alternatives and lower down the capital, a new mode of sun tracking has been developed and feasibility tested. As it applies a single stage collector replacing conventional double stages structure, the new technique has significantly benefits use in high temperature and high concentration solar energy applications. Meanwhile, the stationary or fixed target (receiver offers more convenient working environment for various applications. Large and heavy solar powered Stirling Engine could be placed at the stationary location. On the other advantage offers by the new technique, the optical alignment was reasonably easier and less time consuming.

  3. Development of high-gain gaseous photomultipliers for the visible spectral range

    Lyashenko, A. V.; Breskin, A.; Chechik, R.; Santos, J. M. F. dos; Amaro, F. D.; Veloso, J. F. C. A.

    2009-01-01

    We summarize the development of visible-sensitive gaseous photomultipliers, combining a semitransparent bi-alkali photocathode with a state-of-the-art cascaded electron multiplier. The latter has high photoelectron collection efficiency and a record ion blocking capability. We describe in details the system and methods of photocathode production and characterization, their coupling with the electron multiplier and the gaseous-photomultiplier operation and characterization in a continuous mode...

  4. Origin of high photoconductive gain in fully transparent heterojunction nanocrystalline oxide image sensors and interconnects.

    Jeon, Sanghun; Song, Ihun; Lee, Sungsik; Ryu, Byungki; Ahn, Seung-Eon; Lee, Eunha; Kim, Young; Nathan, Arokia; Robertson, John; Chung, U-In

    2014-11-01

    A technique for invisible image capture using a photosensor array based on transparent conducting oxide semiconductor thin-film transistors and transparent interconnection technologies is presented. A transparent conducting layer is employed for the sensor electrodes as well as interconnection in the array, providing about 80% transmittance at visible-light wavelengths. The phototransistor is a Hf-In-Zn-O/In-Zn-O heterostructure yielding a high quantum-efficiency in the visible range. PMID:25219518

  5. Ultrahigh gain AlGaN/GaN high energy radiation detectors

    Howgate, J.D.; Schoell, S.J.; Schaefer, S.; Stutzmann, M.; Sharp, I.D. [Walter Schottky Institut and Physik Department, Technische Universitaet Muenchen, Am Coulombwall 4, 85748 Garching (Germany); Hofstetter, M.; Schmid, M.; Thalhammer, S. [Helmholtz Zentrum Muenchen, Ingolstaedter Landstrasse 1, 85764 Neuherberg (Germany); Zizak, I. [Helmholtz Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Hable, V.; Greubel, C.; Dollinger, G. [Institut fuer Angewandte Physik und Messtechnik LRT2, Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany)

    2012-08-15

    Due to its remarkable tolerance to high energy ionizing radiation, GaN has recently attracted attention as a promising material for dosimetry applications. However, materials issues that lead to persistent photoconductivity, poor sensitivity, and requirements for large operational voltages have been hurdles to realization of the full potential of this material. Here we demonstrate that the introduction of a two-dimensional electron gas channel, through the addition of AlGaN/GaN heterointerfaces, can be used to create intrinsic amplification of the number of electrons that can be collected from single ionization events, yielding exceptionally large sensitivities in ultralow dose rate regimes. Furthermore, anomalous photo-responses, which severely limit response times of GaN-based devices, can be eliminated using these heterostructures. Measurements using focused monochromatic synchrotron radiation at 1-20 keV, as well as focused 20 MeV protons, reveal that these devices provide the capability for high sensitivity and resolution real time monitoring, which is competitive with and complementary to state-of-the-art detectors. Therefore, AlGaN/GaN heterostructure devices are extremely promising for future applications in fields ranging from high energy physics to medical imaging. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. High gain, low noise, fully complementary logic inverter based on bi-layer WSe2 field effect transistors

    In this article, first, we show that by contact work function engineering, electrostatic doping and proper scaling of both the oxide thickness and the flake thickness, high performance p- and n-type WSe2 field effect transistors (FETs) can be realized. We report record high drive current of 98 μA/μm for the electron conduction and 110 μA/μm for the hole conduction in Schottky barrier WSe2 FETs. Then, we combine high performance WSe2 PFET with WSe2 NFET in double gated transistor geometry to demonstrate a fully complementary logic inverter. We also show that by adjusting the threshold voltages for the NFET and the PFET, the gain and the noise margin of the inverter can be significantly enhanced. The maximum gain of our chemical doping free WSe2 inverter was found to be ∼25 and the noise margin was close to its ideal value of ∼2.5 V for a supply voltage of VDD = 5.0 V.

  7. Results of innovative communication processes on productivity gains in a high technology environment

    Kelly, B. J.

    1985-01-01

    The technology which resulted in performance breakthroughs at engineering and management services is discussed. As a result of the innovative approaches of communicating productivity concepts to the employees, specific outcomes can now be pinpointed at all levels of the organization such as: (1) employee-headed program; (2) performance feedback processes; and (3) an investigative approach to creating leadership. The Lockheed Corporation began the innovative trend in 1974 when they became the first company to introduce quality circles in America. Although some of Lockheed-EMSCO's processes may sound different from traditional improvement processes, the context out of which those to be presented evolved has sustained more than 10 years of positive results through employee involvement activities.

  8. Solidification of highly active wastes

    This document contains the annual reports for the contracts: (A) Glass Technology; (B) Calcination of Highly Active Waste Liquors; (C) Formation and Trapping of Volatile Ruthenium; (D) Deposition of Ruthenium; (E) Enhancement of Off-Gas Aerosol Collection; (F) Volatilisation of Cs, Tc and Te in High Level Waste Vitrification. (author)

  9. Yield gains of coffee plants from phosphorus fertilization may not be generalized for high density planting

    Samuel Vasconcelos Valadares

    2014-06-01

    Full Text Available Inconclusive responses of the adult coffee plant to phosphorus fertilization have been reported in the literature, especially when dealing with application of this nutrient in high density planting systems. Thus, this study was carried out for the purpose of assessing the response of adult coffee plants at high planting density in full production (in regard to yield and their biennial cycle/stability to the addition of different sources and application rates of P in the Zona da Mata region of Minas Gerais, Brazil. The experiment with coffee plants of the Catucaí Amarelo 6/30 variety was carried out over four growing seasons. Treatments were arranged in a full factorial design [(4 × 3 + 1] consisting of four P sources (monoammonium phosphate, simple superphosphate, natural reactive rock phosphate from Algeria (Djebel-Onk, and FH 550®, three P rates (100, 200, and 400 kg ha-1 year-1 of P2O5, and an additional treatment without application of the nutrient (0 kg ha-¹ year-¹. A randomized block experimental design was used with three replicates. The four seasons were evaluated as subplots in a split plot experiment. The P contents in soil and leaves increased with increased rates of P application. However, there was no effect from P application on the yield and its biennial cycle/stability regardless of the source used over the four seasons assessed.

  10. Spectral Analysis of Quantum-Dash Lasers: Effect of Inhomogeneous Broadening of the Active-Gain Region

    Khan, Mohammed Zahed Mustafa

    2012-05-01

    The effect of the active region inhomogeneity on the spectral characteristics of InAs/InP quantum-dash (Qdash) lasers is examined theoretically by solving the coupled set of carrier-photon rate equations. The inhomogeneity due to dash size or composition fluctuation is included in the model by considering dispersive energy states and characterized by a Gaussian envelope. In addition, the technique incorporates multilongitudinal photon modes and homogeneous broadening of the optical gain. The results predict a red shift in the central lasing wavelength of Qdash lasers on increasing the inhomogeneous broadening either explicitly or implicitly, which supports various experimental observations. The threshold current density and the lasing bandwidth are also found to increase. © 2012 IEEE.

  11. A High-Gain Passive UHF-RFID Tag with Increased Read Range.

    Zuffanelli, Simone; Aguila, Pau; Zamora, Gerard; Paredes, Ferran; Martin, Ferran; Bonache, Jordi

    2016-01-01

    In this work, a passive ultra-high frequency radio-frequency identification UHF-RFID tag based on a 1.25 wavelengths thin dipole antenna is presented for the first time. The length of the antenna is properly chosen in order to maximize the tag read range, while maintaining a reasonable tag size and radiation pattern. The antenna is matched to the RFID chip by means of a very simple matching network based on a shunt inductance. A tag prototype, based on the Alien Higgs-3 chip, is designed and fabricated. The overall dimensions are 400 mm × 14.6 mm, but the tag width for most of its length is delimited by the wire diameter (0.8 mm). The measured read range exhibits a maximum value of 17.5 m at the 902-928 MHz frequency band. This represents an important improvement over state-of-the-art passive UHF-RFID tags. PMID:27455274

  12. Sensitivity Gains, Linearity, and Spectral Reproducibility in Nonuniformly Sampled Multidimensional MAS NMR Spectra of High Dynamic Range.

    Suiter, Christopher L.; Paramasivam, Sivakumar; Hou, Guangjin; Sun, Shangjin; Rice, David M.; Hoch, Jeffrey C.; Rovnyak, David S.; Polenova, Tatyana E.

    2014-04-22

    Recently, we have demonstrated that considerable inherent sensitivity gains are attained in MAS NMR spectra acquired by nonuniform sampling (NUS) and introduced maximum entropy interpolation (MINT) processing that assures the linearity of transformation between the time and frequency domains. In this report, we examine the utility of the NUS/MINT approach in multidimensional datasets possessing high dynamic range, such as homonuclear 13C–13C correlation spectra. We demonstrate on model compounds and on 1–73-(U-13C,15N)/74–108-(U-15N) E. coli thioredoxin reassembly, that with appropriately constructed 50 % NUS schedules inherent sensitivity gains of 1.7–2.1-fold are readily reached in such datasets. We show that both linearity and line width are retained under these experimental conditions throughout the entire dynamic range of the signals. Furthermore, we demonstrate that the reproducibility of the peak intensities is excellent in the NUS/MINT approach when experiments are repeated multiple times and identical experimental and processing conditions are employed. Finally, we discuss the principles for design and implementation of random exponentially biased NUS sampling schedules for homonuclear 13C–13C MAS correlation experiments that yield high quality artifact-free datasets.

  13. High elastic polyurethane/carbon nanotube composite laminate for structure health monitoring by gain shifting of antenna sensing element

    Olejnik, Robert; Slobodian, Petr; Matyas, Jiri; Gorakh Babar, Dipak

    2016-03-01

    The composite of carbon nanotubes and polyurethane (PU) was prepared by simple filtration technique. The PU nonwoven filtration membrane was prepared by electrospinning. A layer of carbon nanotubes was prepared by vacuum filtration on the surface of PU membrane. The resulting composite was subsequently placed on highly elastic polyurethane substrate. The contribution shows an efficient method of preparing the sensing element for monitoring the state of strain of loaded structures by using highly elastic polyurethane / carbon nanotubes composite. This sensor has been involved as passive antenna with stable resonance frequency of 650 MHz. When it is get deformed in the range from 0 to 3.5% the sensor gain was changing from -39 dB to - 19.45 dB. But if it is get deformed by 15% and again measured strain from 0 to 3.5%, sensor gain was changing from -33 dB to -12.3 dB, which clearly indicates the damage of structure.

  14. Adaptive Robust Output Feedback Control for a Marine Dynamic Positioning System Based on a High-Gain Observer.

    Du, Jialu; Hu, Xin; Liu, Hongbo; Chen, C L Philip

    2015-11-01

    This paper develops an adaptive robust output feedback control scheme for dynamically positioned ships with unavailable velocities and unknown dynamic parameters in an unknown time-variant disturbance environment. The controller is designed by incorporating the high-gain observer and radial basis function (RBF) neural networks in vectorial backstepping method. The high-gain observer provides the estimations of the ship position and heading as well as velocities. The RBF neural networks are employed to compensate for the uncertainties of ship dynamics. The adaptive laws incorporating a leakage term are designed to estimate the weights of RBF neural networks and the bounds of unknown time-variant environmental disturbances. In contrast to the existing results of dynamic positioning (DP) controllers, the proposed control scheme relies only on the ship position and heading measurements and does not require a priori knowledge of the ship dynamics and external disturbances. By means of Lyapunov functions, it is theoretically proved that our output feedback controller can control a ship's position and heading to the arbitrarily small neighborhood of the desired target values while guaranteeing that all signals in the closed-loop DP control system are uniformly ultimately bounded. Finally, simulations involving two ships are carried out, and simulation results demonstrate the effectiveness of the proposed control scheme. PMID:25769172

  15. Review: insights gained from modelling high-grade glioma in the mouse.

    Rankin, S L; Zhu, G; Baker, S J

    2012-06-01

    High-grade gliomas (HGGs) are devastating primary brain tumours with poor outcomes. Advances towards effective treatments require improved understanding of pathogenesis and relevant model systems for preclinical testing. Mouse models for HGG provide physiologically relevant experimental systems for analysis of HGG pathogenesis. There are advantages and disadvantages to the different methodologies used to generate such models, including implantation, genetic engineering or somatic gene transfer approaches. This review highlights how mouse models have provided insights into the contribution of specific mutations to tumour initiation, progression and phenotype, the influence of tumour micro-environment, and the analysis of cell types that can give rise to glioma. HGGs are a heterogeneous group of tumours, and the complexity of diverse mutations within common signalling pathways as well as the developmental and cell-type context of transformation contributes to the overall diversity of glioma phenotype. Enhanced understanding of the mutations and cell types giving rise to HGG, along with the ability to design increasingly complex mouse models that more closely simulate the process of human gliomagenesis will continue to provide improved experimental systems for dissecting mechanisms of disease pathogenesis and for preclinical testing. PMID:22035336

  16. Replacing Non-Active Video Gaming by Active Video Gaming to Prevent Excessive Weight Gain in Adolescents.

    Monique Simons

    Full Text Available The aim of the current study was to evaluate the effects of and adherence to an active video game promotion intervention on anthropometrics, sedentary screen time and consumption of sugar-sweetened beverages and snacks among non-active video gaming adolescents who primarily were of healthy weight.We assigned 270 gaming (i.e. ≥ 2 hours/week non-active video game time adolescents randomly to an intervention group (n = 140 (receiving active video games and encouragement to play or a waiting-list control group (n = 130. BMI-SDS (SDS = adjusted for mean standard deviation score, waist circumference-SDS, hip circumference and sum of skinfolds were measured at baseline, at four and ten months follow-up (primary outcomes. Sedentary screen time, physical activity, consumption of sugar-sweetened beverages and snacks, and process measures (not at baseline were assessed with self-reports at baseline, one, four and ten months follow-up. Multi-level-intention to treat-regression analyses were conducted.The control group decreased significantly more than the intervention group on BMI-SDS (β = 0.074, 95%CI: 0.008;0.14, and sum of skinfolds (β = 3.22, 95%CI: 0.27;6.17 (overall effects. The intervention group had a significantly higher decrease in self-reported non-active video game time (β = -1.76, 95%CI: -3.20;-0.32 and total sedentary screen time (Exp (β = 0.81, 95%CI: 0.74;0.88 than the control group (overall effects. The process evaluation showed that 14% of the adolescents played the Move video games every week ≥ 1 hour/week during the whole intervention period.The active video game intervention did not result in lower values on anthropometrics in a group of 'excessive' non-active video gamers (mean ~ 14 hours/week who primarily were of healthy weight compared to a control group throughout a ten-month-period. Even some effects in the unexpected direction were found, with the control group showing lower BMI-SDS and skin folds than the intervention

  17. Weight gain and inflammation regulate aromatase expression in male adipose tissue, as evidenced by reporter gene activity.

    Polari, L; Yatkin, E; Martínez Chacón, M G; Ahotupa, M; Smeds, A; Strauss, L; Zhang, F; Poutanen, M; Saarinen, N; Mäkelä, S I

    2015-09-01

    Obesity and white adipose tissue (WAT) inflammation are associated with enhanced aromatization in women, but little is known about the regulation of aromatase (CYP19A1) gene expression in male WAT. We investigated the impact of weight gain and WAT inflammation on the regulation of CYP19A1 in males, by utilizing the hARO-Luc aromatase reporter mouse model containing a >100-kb 5'-region of the human CYP19A1 gene. We show that hARO-Luc reporter activity is enhanced in WAT of mice with increased adiposity and inflammation. Dexamethasone and TNFα, as well as forskolin and phorbol 12-myristate 13-acetate, upregulate hARO-Luc activity, suggesting the involvement of promoters I.4 and I.3/II. Furthermore, we show that diet enriched with antioxidative plant polyphenols attenuates WAT inflammation and hARO-Luc activity in obese males. In conclusion, our data suggest that obesity-associated WAT inflammation leads to increased peripheral CYP19A1 expression in males, and that polyphenol-enriched diet may have the potential to attenuate excessive aromatization in WAT of obese men. PMID:26054748

  18. A new design methodology of obtaining wide band high gain broadband parametric source for infrared wavelength applications

    Maji, Partha Sona; Roy Chaudhuri, Partha

    2016-03-01

    In this article, we have presented a new design methodology of obtaining wide band parametric sources based on highly nonlinear chalcogenide material of As2S3. The dispersion profile of the photonic crystal fiber (PCF) has been engineered wisely by reducing the diameter of the second air-hole ring to have a favorable higher order dispersion parameter. The parametric gain dependence upon fiber length, pump power, and different pumping wavelengths has been investigated in detail. Based upon the nonlinear four wave mixing phenomenon, we are able to achieve a wideband parametric amplifier with peak gain of 29 dB with FWHM of ≈2000 nm around the IR wavelength by proper tailoring of the dispersion profile of the PCF with a continuous wave Erbium (Er3+)-doped ZBLAN fiber laser emitting at 2.8 μm as the pump source with an average power of 5 W. The new design methodology will unleash a new dimension to the chalcogenide material based investigation for wavelength translation around IR wavelength band.

  19. Criterion of transverse coherence of self-amplified spontaneous emission in high gain free electron laser amplifiers

    In a high gain free electron laser amplifier based on Self-Amplified Spontaneous Emission (SASE) the spontaneous radiation generated by an electron beam near the undulator entrance is amplified many orders of magnitude along the undulator. The transverse coherence properties of the amplified radiation depends on both the amplification process and the coherence of the seed radiation (the undulator radiation generated in the first gain length or so). The evolution of the transverse coherence in the amplification process is studied based on the solution of the coupled Maxwell-Vlasov equations including higher order transverse modes. The coherence of the seed radiation is determined by the number of coherent modes in the phase space area of the undulator radiation. We discuss the criterion of transverse coherence and identify governing parameters over a broad range of parameters. In particular we re-examine the well known emittance criterion for the undulator radiation, which states that full transverse coherence is guaranteed if the rms emittance is smaller than the wavelength divided by 4π. It is found that this criterion is modified for SASE because of the different optimization conditions required for the electron beam. Our analysis is a generalization of the previous study by Yu and Krinsky for the case of vanishing emittance with parallel electron beam. Understanding the transverse coherence of SASE is important for the X-ray free electron laser projects now under consideration at SLAC and DESY

  20. Multi-mode theory of pulsed twin beams generation using a high gain fiber optical parametric amplifier

    Guo, Xueshi; Liu, Nannan; Ou, Z Y

    2013-01-01

    Using the Bogoliubov transformation in multi-frequency modes to describe the evolution of the non-degenerate signal and idler twin beams, we theoretically investigate the quantum noise properties of the pulse pumped high gain fiber optical parametric amplifiers (FOPA). The results show that the noise figure of the FOPA is generally greater than the 3 dB quantum limit unless the joint spectral function is factorable and the spectrum of the input signal well matches the gain spectrum in the signal band. However, the intensity difference noise of the twin beams, which weakly depends on the joint spectral function, can be significantly less than the shot-noise limit when the temporal modes of the pump and the input signal are properly matched. Moreover, to closely resemble the real experimental condition, the quantum noise of twin beams generated from a broadband FOPA is numerically studied by taking the various kinds of experimental imperfections into account. Our study is not only useful for developing a compac...

  1. Telmisartan prevents weight gain and obesity through activation of peroxisome proliferator-activated receptor-delta-dependent pathways

    He, Hongbo; Yang, Dachun; Ma, Liqun;

    2010-01-01

    -gamma expression, whereas neither candesartan nor losartan affected PPAR-delta expression. In vivo, long-term administration of telmisartan significantly reduced visceral fat and prevented high-fat diet-induced obesity in wild-type mice and hypertensive rats but not in PPAR-delta knockout mice. Administration of...

  2. Theory of quantum frequency conversion and type-II parametric down-conversion in the high-gain regime

    Frequency conversion (FC) and type-II parametric down-conversion (PDC) processes serve as basic building blocks for the implementation of quantum optical experiments: type-II PDC enables the efficient creation of quantum states such as photon-number states and Einstein–Podolsky–Rosen (EPR)-states. FC gives rise to technologies enabling efficient atom–photon coupling, ultrafast pulse gates and enhanced detection schemes. However, despite their widespread deployment, their theoretical treatment remains challenging. Especially the multi-photon components in the high-gain regime as well as the explicit time-dependence of the involved Hamiltonians hamper an efficient theoretical description of these nonlinear optical processes. In this paper, we investigate these effects and put forward two models that enable a full description of FC and type-II PDC in the high-gain regime. We present a rigorous numerical model relying on the solution of coupled integro-differential equations that covers the complete dynamics of the process. As an alternative, we develop a simplified model that, at the expense of neglecting time-ordering effects, enables an analytical solution. While the simplified model approximates the correct solution with high fidelity in a broad parameter range, sufficient for many experimental situations, such as FC with low efficiency, entangled photon-pair generation and the heralding of single photons from type-II PDC, our investigations reveal that the rigorous model predicts a decreased performance for FC processes in quantum pulse gate applications and an enhanced EPR-state generation rate during type-II PDC, when EPR squeezing values above 12 dB are considered. (paper)

  3. Transmission Enhancement of High-$k$ Waves through Metal-InGaAsP Multilayers Calculated via Scattering Matrix Method with Semi-Classical Optical Gain

    Smalley, Joseph S T; Shahin, Shiva; Kanté, Boubacar; Fainman, Yeshaiahu

    2015-01-01

    We analyze the steady-state transmission of high-momentum (high-$k$) electromagnetic waves through metal-semiconductor multilayer systems with loss and gain in the near-infrared (NIR). Using a semi-classical optical gain model in conjunction with the scattering matrix method (SMM), we study indium gallium arsenide phosphide (InGaAsP) quantum wells as the active semiconductor, in combination with the metals, aluminum-doped zinc oxide (AZO) and silver (Ag). Under moderate external pumping levels, we find that NIR transmission through Ag/InGaAsP systems may be enhanced by several orders of magnitude relative to the unpumped case, over a large angular and frequency bandwidth. Conversely, transmission enhancement through AZO/InGaAsP systems is orders of magnitude smaller, and has a strong frequency dependence. We discuss the relative importance of Purcell enhancement on our results and validate analytical calculations based on the SMM with numerical finite-difference time domain simulations.

  4. Study of the output pulse stability of a cascaded high-gain harmonic generation free-electron laser

    Wang, Zhen; Feng, Chao; Gu, Qiang; Zhao, Zhentang

    2016-06-01

    Cascading stages of high-gain harmonic generation (HGHG) have been demonstrated to be a promising candidate for producing fully coherent soft X-ray radiation directly from UV seed sources. However, the large shot-to-shot output pulse energy fluctuation may still be a serious problem for its user applications. In this paper, we study the effects of various electron beam parameters jitters on the output pulse energy fluctuations of a two-stage HGHG. Theoretical calculations and intensive simulations have been performed and the results demonstrate that the relative timing jitter between the electron bunch and the seed laser pulse is mainly responsible for the large output pulse energy fluctuation. Several methods that may be helpful to improve the FEL stability have also been discussed.

  5. Parameter Analysis For A High-Gain Harmonic Generation FEL By Numerical Calculation Based On 1D Theory

    Li, Yuhui; Zhang, Shancai

    2004-01-01

    The high-gain harmonic generation (HGHG) free-electron laser (FEL) is an important candidate for a fourth-generation light source. Lots of theoretical work has been performed. Recently a further 1D theory about HGHG FEL has been developed. It considers the effects of different parameters for the whole process. An initial program based on this theory has been made. In this paper, a brief comparison of the results from this 1D program and from TDA (3D code) is discussed. It also analyses the parameters for Shanghai deep ultra violate free-electron laser source (SDUV-FEL), including electron beam energy spread, seed laser power, strength of dispersion section etc.

  6. Scaling theory and hydrodynamically equivalent design. Scenario for proof of principle of high gain inertial confinement fusion

    The EPOC (Equivalent Physics Of Confinement) scenario for the proof of principle of high gain inertial confinement fusion is presented, with the concept of 'hydrodynamically equivalent implosions' playing a key role. Scaling laws on the target and confinement parameters are derived by applying the Lie group analysis to the PDE (Partially Differential Equations) chain of the hydrodynamic system. The results shows that the conventional scaling law based on adiabatic approximation differs significantly from the scaling law that considers electron heat conduction and other energy-transport effects. Confinement plasma parameters of the hot spot, such as the central temperature and the areal mass density at peak compression, are obtained with a self-similar solution for spherical implosions. Ignition energy scaling in terms of the implosion velocity and the isentrope parameter is also discussed by reviewing several recent works. (author)

  7. Design and Analysis of Parabolic Reflector with High Gain Pencil Beam and Low side lobes by Varying feed

    Prabhakar.Telagarapu

    2011-09-01

    Full Text Available The far field radiation pattern from a parabolic reflector depends on the primary radiation pattern which is the radiation pattern of the feed element placed and also on the type and dimensions of reflector used. Therefore in this paper first analysis of the primary patterns of different elements like dipole, horn is done by considering different dimensions. In addition the beam efficiency and the dipole multiplication patterns for different lengths were also calculated. . A parabolic reflector has been selected as the reflector because it produces high gain pencil beam with low side lobes. Using general and aperture approximation methods the radiation patterns have been plotted in both the azimuth and elevation planes. The comparison of dipole, square corner and horn feeds based on the characteristics like intensity, directivity has also been done and the resultant patterns were obtained.

  8. Implosion scaling and hydro dynamically equivalent target design - Strategy for proof of principle of high gain inertial fusion

    Scaling laws for hydro dynamically similar implosions are derived by applying Lie group analysis to the set of partial differential equations for the hydrodynamic system. Physically this implies that any fluid system belonging to a common similarity group evolves quite in the same manner including hydrodynamic instabilities. The scalings strongly depend on the description of the energy transport, i.e., whether the fluid system is heat conductive or adiabatic. Under a fully specified group transformation including prescriptions on the laser wavelength and the ionization state, the hydrodynamic similarity can still be preserved even when the system is cooperated with such other energy sources as classical laser absorption, hot electrons, local alpha heating, and bremsstrahlung loss. The results are expected to give the basis of target design and diagnostics for scaled high gain experiments in future. (author)

  9. Gimbals Drive and Control Electronics Design, Development and Testing of the LRO High Gain Antenna and Solar Array Systems

    Chernyakov, Boris; Thakore, Kamal

    2010-01-01

    Launched June 18, 2009 on an Atlas V rocket, NASA's Lunar Reconnaissance Orbiter (LRO) is the first step in NASA's Vision for Space Exploration program and for a human return to the Moon. The spacecraft (SC) carries a wide variety of scientific instruments and provides an extraordinary opportunity to study the lunar landscape at resolutions and over time scales never achieved before. The spacecraft systems are designed to enable achievement of LRO's mission requirements. To that end, LRO's mechanical system employed two two-axis gimbal assemblies used to drive the deployment and articulation of the Solar Array System (SAS) and the High Gain Antenna System (HGAS). This paper describes the design, development, integration, and testing of Gimbal Control Electronics (GCE) and Actuators for both the HGAS and SAS systems, as well as flight testing during the on-orbit commissioning phase and lessons learned.

  10. Instructional practices among science departments with high, moderate, and low gains on the Connecticut Academic Performance Test

    Kachergis, Theodora R.

    The purpose of this study was to ascertain whether the instructional practices of performance-based, inquiry-based, and authentic-based learning strategies, and rubric use are related to improvement on the science portion of the Connecticut Academic Performance Test [CAPT], as indicated by CAPT gains from 1995--2001. Data were collected for this study by a survey/interview of 63 Connecticut high schools and their 118 certified biology teachers, who had participated in the science CAPT administration within that same school district during 1995--2001. Results from the analysis of the data indicate a significant relationship between strategy and rubric use and CAPT science score outputs. Those schools having the highest levels of strategy and rubric use also demonstrated high CAPT gains and increasing CAPT scores, over time. It was also determined that a strong relationship exists between the percentage of the ERG's goal for CAPT index and those ERGs, using strategies and/or rubrics proficiently. The major findings of the study reveal that teachers demonstrate a confusion of strategy/rubric meaning, as indicated by the low proficiency levels of their submitted strategy and rubric samples, despite high indicators of use for the three learning strategies and rubrics. In addition, rubrics are rated highly by the sample, but are not employed at the high levels of reported favorability. Further analysis determines that objective forms of assessment are used more frequently than strategy and rubric use, and may be implicated for the decreased use of rubrics. Although survey data indicate that 90% of the sample reported "Satisfactory" to "Excellent" levels of annual score updates within their respective districts, teachers requested a need for increased pre- and in-service professional development in the use of all three strategies and rubrics: particularly non-tenured teachers expressed a need for basic CAPT information and samples of strategy and rubric use, while

  11. Submonolayer InGaAs/GaAs quantum-dot lasers with high modal gain and zero-linewidth enhancement factor

    Xu, Zhangcheng; Birkedal, Dan; Juhl, Michael; Hvam, Jørn Märcher

    2004-01-01

    The gain spectra of a submonolayer (SML) InGaAs/GaAs quantum dot (QD) laser working at 30°C were measured using the Hakki–Paoli method. It is found that the maximum modal gain of QD ground states is as high as 44 cm–1 and no gain saturation occurs below the threshold at the lasing wavelength of 964.......1 nm. When the injection current is about 0.98 times the threshold, the gain spectrum becomes symmetric with respect to the lasing wavelength, and zero-linewidth enhancement factor is observed. These properties are attributed to the high density and the high uniformity of SML QDs in our laser diode....

  12. High-power diode side-pumped Nd:YAG laser on the low gain three lines near 1.1 μm

    Wang, Z.; Bo, Y.; Xie, S.; Li, C.; Xu, Y.; Yang, F.; Xu, J.; Peng, Q.; Zhang, J.; Cui, D.; Xu, Z.

    2011-07-01

    We demonstrate a high-power diode side-pumped Nd:YAG laser on the low gain three lines near 1.1 μm. By tuning the tilting angle of a solid etalon in the cavity, the laser can be selectively operated at 1112, 1116 and 1123 nm either in continuous-wave (CW) mode or in actively Q-switched (QS) mode, respectively. The highest average CW output powers were 75, 47 and 71 W at 1112, 1116 and 1123 nm, respectively. The transmittances of the etalon were calculated to analyze the performance of the laser at the three lines. Furthermore, a computational model of a three-wavelength laser based on rate equations was employed to examine the line selectivity of the three lines near 1.1 μm at different tilting angles of the etalon.

  13. Consumption of clarified grapefruit juice ameliorates high-fat diet induced insulin resistance and weight gain in mice.

    Rostislav Chudnovskiy

    Full Text Available To determine the metabolic effects of grapefruit juice consumption we established a model in which C57Bl/6 mice drank 25-50% sweetened GFJ, clarified of larger insoluble particles by centrifugation (cGFJ, ad libitum as their sole source of liquid or isocaloric and sweetened water. cGFJ and control groups consumed similar amounts of liquids and calories. Mice fed a high-fat diet and cGFJ experienced a 18.4% decrease in weight, a 13-17% decrease in fasting blood glucose, a three-fold decrease in fasting serum insulin, and a 38% decrease in liver triacylglycerol values, compared to controls. Mice fed a low-fat diet that drank cGFJ experienced a two-fold decrease in fasting insulin, but not the other outcomes observed with the high-fat diet. cGFJ consumption decreased blood glucose to a similar extent as the commonly used anti-diabetic drug metformin. Introduction of cGFJ after onset of diet-induced obesity also reduced weight and blood glucose. A bioactive compound in cGFJ, naringin, reduced blood glucose and improved insulin tolerance, but did not ameliorate weight gain. These data from a well-controlled animal study indicate that GFJ contains more than one health-promoting neutraceutical, and warrant further studies of GFJ effects in the context of obesity and/or the western diet.

  14. A 71 dB Gain, High Efficiency Relativistic Klystron using a High Current Linear Accelerator Traveling Wave Buncher Output Structure

    After five years of operation, the 17 GHz MKII relativistic klystron in service at the MIT Plasma Science and Fusion Center was upgraded with a new output structure to provide a common source of high peak power for continuing operation of the 17 GHz linac, for RF gun testing and for energizing a recently developed circularly polarized beam deflection RF system to evaluate the ultra short electron bunch performance of the linac. The salient features of the impedance and phase velocity tapered new traveling wave output structure designed for high gain and stability are described; and initial high power test results of the 17 GHz relativistic klystron are presented. The output structure was designed as a beam driven bunching and phase shifting 2π/3 mode circuit using codes that were developed over a 40 year period designing, fabricating and testing high current traveling wave linac bunchers. The electrical length of the new (MKIII) output circuit was extended to 1200 degrees using a group to phase velocity harmonic mean ratio of 0.124 to provide total skin losses of less than 5 percent and a phase/frequency sensitivity of only 0.6 degree/MHz. A dual feed racetrack shaped output cavity having a decelerating gradient of 150 kV/cm and beam apertures substantially larger than λ0/2, to allow reduction of space charge debunching forces, are added advantages of this 25 MW, 71 dB gain RF amplifier

  15. Integrated Three-Voltage-Booster DC-DC Converter to Achieve High Voltage Gain with Leakage-Energy Recycling for PV or Fuel-Cell Power Systems

    Chih-Lung Shen

    2015-09-01

    Full Text Available In this paper, an integrated three-voltage-booster DC-DC (direct current to direct current converter is proposed to achieve high voltage gain for renewable-energy generation systems. The proposed converter integrates three voltage-boosters into one power stage, which is composed of an active switch, a coupled-inductor, five diodes, and five capacitors. As compared with conventional high step-up converters, it has a lower component count. In addition, the features of leakage-energy recycling and switching loss reduction can be accomplished for conversion efficiency improvement. While the active switch is turned off, the converter can inherently clamp the voltage across power switch and suppress voltage spikes. Moreover, the reverse-recovery currents of all diodes can be alleviated by leakage inductance. A 200 W prototype operating at 100 kHz switching frequency with 36 V input and 400 V output is implemented to verify the theoretical analysis and to demonstrate the feasibility of the proposed high step-up DC-DC converter.

  16. High-power active devices

    Carroll, E

    2006-01-01

    Very high-power (HP) electronics represents a small part of the electronics market. In semiconductor terms, HP represents a world device market of 600 million euros out of a total 200 billion euros for all semiconductors—a mere 0.3 per cent. At the multi-megawatt spectral end, the numbers are even smaller, so that it is quite common for electronics engineers to be unaware of developments in Very High Power (VHP). In this presentation we discuss the categories of VHP active devices, the basic topologies in which they operate, and the trend towards higher voltage and current. New press-pack technologies are introduced and the salient differences between Insulated Gate Bipolar Transistors (IGBTs) and Integrated Gate Commutated Thyristors (IGCTs) are compared. Finally, recent developments in turn-off ratings for both these devices are presented.

  17. Parameter analysis for a high-gain harmonic generation FEL using a recently developed 3D polychromatic code

    Biedron, S G; Yu, L H

    2000-01-01

    One possible design for a fourth-generation light source is the high-gain harmonic generation (HGHG) free-electron laser (FEL). Here, a coherent seed with a wavelength at a subharmonic of the desired output radiation interacts with the electron beam in an energy-modulating section. This energy modulation is then converted into spatial bunching while traversing a dispersive section (a three-dipole chicane). The final step is passage through an undulator tuned to the desired higher harmonic output wavelength. The coherent seed serves to suppress and can be at a much lower subharmonic of the output radiation. Recently, a 3D code that includes multiple frequencies, multiple undulators (both in quantity and/or type), quadrupole magnets, and dipole magnets was developed to easily simulate HGHG. Here, a brief review of the HGHG theory, the code development, the Accelerator Test Facility's (ATF) HGHG FEL experimental parameters, and the parameter analysis from simulations of this specific experiment will be discussed...

  18. Parameter analysis for a high-gain harmonic generation FEL using a recently developed 3D polychromatic code

    One possible design for a fourth-generation light source is the high-gain harmonic generation (HGHG) free-electron laser (FEL). Here, a coherent seed with a wavelength at a subharmonic of the desired output radiation interacts with the electron beam in an energy-modulating section. This energy modulation is then converted into spatial bunching while traversing a dispersive section (a three-dipole chicane). The final step is passage through a radiative section, an undulator tuned to the desired higher harmonic output wavelength. The coherent seed serves to remove noise and can be at a much lower subharmonic of the output radiation, thus eliminating the concerns found in self-amplified spontaneous emission (SASE) and seeded FELs, respectively. Recently, a 3D code that includes multiple frequencies, multiple undulatory (both in quantity and/or type), quadruple magnets, and dipole magnets was developed to easily simulate HGHG. Here, a brief review of the HGHG theory, the code development, the Accelerator Test Facility's (ATF) HGHG FEL experimental parameters, and the parameter analysis from simulations of this specific experiment will be discussed

  19. Parameter analysis for a high-gain harmonic generation FEL using a recently developed 3D polychromatic code

    One possible design for a fourth-generation light source is the high-gain harmonic generation (HGHG) free-electron laser (FEL). Here, a coherent seed with a wavelength at a subharmonic of the desired output radiation interacts with the electron beam in an energy-modulating section. This energy modulation is then converted into spatial bunching while traversing a dispersive section (a three-dipole chicane). The final step is passage through an undulator tuned to the desired higher harmonic output wavelength. The coherent seed serves to suppress and can be at a much lower subharmonic of the output radiation. Recently, a 3D code that includes multiple frequencies, multiple undulators (both in quantity and/or type), quadrupole magnets, and dipole magnets was developed to easily simulate HGHG. Here, a brief review of the HGHG theory, the code development, the Accelerator Test Facility's (ATF) HGHG FEL experimental parameters, and the parameter analysis from simulations of this specific experiment will be discussed

  20. Fuzzy PI Controller Based Fault Analysis and Recovery in Sensorless BLDC Motor using High Gain Hybrid Converter (HGHC

    R. Jayanthi

    2014-12-01

    Full Text Available Renewable Energy Sources (RES has been widely used in various applications due to increase in power demand. In this study, a High Gain Hybrid Converter (HGHC has been used to utilize maximum power from PV panel and to control the battery mode of operation such as charging/discharging in an efficient manner. In the load side, sensor less BLDC motor has been used in this study. After the back EMF is generated in the load side BLDC motor, it is taken as feedback to the HGHC. So, this will act as the main supply and thus, more power can be saved. Moreover, this research study also focuses on the transient analysis of the BLDC motor. The inverter in BLDC motor plays a vital role as it is responsible for flux generation and fixing up of angle ‘θ’ to the motor for its operation. So, the failures in the switches of the inverter would greatly affect the overall functioning of the BLDC motor. Thus, this research study focuses on the failure analysis of these switches in the inverter. In order to analyze and recover these faults, error controllers have been used in this proposed study. The simulations are carried out in MATLAB r2011a and the results are taken. The results show the significant performance of the proposed model.

  1. Wavelength-Dependent Transient Characteristics Caused by Gain Saturation in Highly Nonlinear Fiber-Based Raman Amplifiers

    Shinobu; Tamaoki; Tetsufumi; Tsuzaki; Motoki; Kakui; Masayuki; Shigematsu

    2003-01-01

    We have investigated the transient characteristics of discrete Raman Amplifiers and found that the response time caused by gain saturation is dependent upon the wavelength, which corresponds to the effective length of the pump light.

  2. Positive Effect of Severe Nakagami-m Fading on the Performance of Multiuser TAS/MRC Systems with High Selection Gain

    Chia-Chun Hung

    2012-01-01

    Full Text Available This paper investigates the positive effect of severe Nakagami-m fading on the performance of multiuser transmit antenna selection/maximal-ratio combining (TAS/MRC systems with high selection gain. Both amount of fading (AF and symbol error rate (SER of M-QAM are derived as closed-form expressions for integer m. For arbitrary m, the AF and the SER are expressible as a single infinite series of Gamma function and Gauss hypergeometric function, respectively. The analytical results lead to the following observations. First, the SER performance can demonstrate the positive effect of severe Nakagami-m fading on multiuser TAS/MRC systems with high selection gain. Second, the AF performance only exhibits the negative impact of severe fading regardless of high selection gain. Last, the benefit of severe fading to the system performance diminishes at high signal-to-noise ratio (SNR.

  3. Spontaneous Activity, Economy of Activity, and Resistance to Diet-Induced Obesity in Rats Bred for High Intrinsic Aerobic Capacity

    Novak, Colleen M.; Escande, Carlos; Burghardt, Paul R.; Zhang, Minzhi; Barbosa, Maria Teresa; Chini, Eduardo N.; Britton, Steven L.; Koch, Lauren G.; Akil, Huda; James A Levine

    2010-01-01

    Though obesity is common, some people remain resistant to weight gain even in an obesogenic environment. The propensity to remain lean may be partly associated with high endurance capacity along with high spontaneous physical activity and the energy expenditure of activity, called non-exercise activity thermogenesis (NEAT). Previous studies have shown that high-capacity running rats (HCR) are lean compared to low-capacity runners (LCR), which are susceptible to cardiovascular disease and meta...

  4. A Simple Low-Cost Shared-Aperture Dual-Band Dual-Polarized High Gain Antenna for Synthetic Aperture Radars

    Qin, Fan; Gao, Steven; Qi, Luo; Mao, Chunxu; Gu, Chao; Wei, Gao; Xu, Jiadong; Li, Jianzhou; Wu, Changying; Zheng, Kuisong; Zheng, Shufeng

    2016-01-01

    This paper presents a novel shared-aperture dual-band dual-polarized high-gain antenna for potential applications in synthetic aperture radars (SAR). To reduce the complexity of SAR antennas, a dual-band dual-polarized high gain antenna based on the concept of Fabry-Perot resonant cavity is designed. This antenna operates in both C and X bands with a frequency ratio of 1:1.8. To form two separate resonant cavities, two frequency selective surface (FSS) layers are employed, leading to high fle...

  5. Inhibitory effects of Leonurus sibiricus on weight gain after menopause in ovariectomized and high-fat diet-fed mice.

    Kim, Jangseon; Kim, Mi Hye; Choi, You Yeon; Hong, Jongki; Yang, Woong Mo

    2016-07-01

    Leonurus sibiricus, also called motherwort, is a well-known functional food and medicinal herb. It has been known to possess beneficial properties for women's health, especially for aged women. Estrogen deficiency in the menopause could induce lipid metabolic abnormalities in body fat, resulting in obesity. In this study, the inhibitory effects of L. sibiricus on obesity after the menopause were investigated. Female C57BL/6 mice were ovariectomized and fed high-fat diet (HFD) for 12 weeks. Following an induction period, aqueous extracts of L. sibiricus (LS) were orally administrated for 6 weeks. The body, uterine, and visceral fat weights were measured immediately after the animals were killed. Histological analysis was performed to monitor fat and liver. Serum levels of glucose, triglyceride, total cholesterol, and LDL-cholesterol were evaluated. In addition, the expression of lipases was analyzed. Total body weight was significantly decreased by LS treatment. Histological changes in adipocyte size were shown along with a decrease of visceral fat weight in the LS-treated group. In addition, the fat infiltration of liver was reduced by LS administration. LS-treated mice experienced decreases of serum triglyceride, total cholesterol, and LDL-cholesterol levels. The expression of HSL and ATGL was significantly increased by LS treatment. These results suggest that LS could regulate the lipid metabolism via an increase of lipases expression in ovariectomized and HFD-fed mice. LS might be a novel candidate for a functional food to inhibit weight gain after the menopause. PMID:26899238

  6. Effect of computer mouse gain and visual demand on mouse clicking performance and muscle activation in a young and elderly group of experienced computer users

    Sandfeld, Jesper; Jensen, Bente R.

    2005-01-01

    The present study evaluated the specific effects of motor demand and visual demands on the ability to control motor output in terms of performance and muscle activation. Young and elderly subjects performed multidirectional pointing tasks with the computer mouse. Three levels of mouse gain and th...... only to a minor degree influenced by mouse gain (and target sizes) indicating that stability of the forearm/hand is of significance during computer mouse control. The study has implications for ergonomists, pointing device manufacturers and software developers....

  7. ACTIVE MEDIA: Gain dynamics in a pulsed laser amplifier on CO-He, CO-N2 and CO-O2 gas mixtures

    Vetoshkin, S. V.; Ionin, Andrei A.; Klimachev, Yu M.; Kozlov, A. Yu; Kotkov, A. A.; Rulev, O. A.; Seleznev, L. V.; Sinitsyn, D. V.

    2007-02-01

    Small-signal gain (SSG) dynamics G(t) in the active medium of a pulsed laser amplifier operating on the v+1→vP(J) vibrational-rotational transitions of the CO molecule, including high (v > 15) vibrational transitions, is studied experimentally. It is demonstrated that as the vibrational number increases from 7 to 31, G changes with time slower, while Gmax decreases in this case by three times. It is found that at a fixed value of v the rate of the SSG rise increases with increasing the rotational number J > 6. It is shown that in oxygen-containing gas mixtures (CO:O2 = 1:19) the value of Gmax at low vibrational levels (for v < 13) can substantially exceed Gmax in mixtures containing nitrogen (CO:N2 = 1:19) instead of oxygen. It is found that the efficiency (47%) of a CO laser on mixtures with a high concentration of oxygen considerably exceeds the efficiency (30%) of a CO laser operating on a nitrogen-containing mixture.

  8. Gain of function AMP-activated protein kinase γ3 mutation (AMPKγ3R200Q) in pig muscle increases glycogen storage regardless of AMPK activation.

    Scheffler, Tracy L; Park, Sungkwon; Roach, Peter J; Gerrard, David E

    2016-06-01

    Chronic activation of AMP-activated protein kinase (AMPK) increases glycogen content in skeletal muscle. Previously, we demonstrated that a mutation in the ryanodine receptor (RyR1(R615C)) blunts AMPK phosphorylation in longissimus muscle of pigs with a gain of function mutation in the AMPKγ3 subunit (AMPKγ3(R200Q)); this may decrease the glycogen storage capacity of AMPKγ3(R200Q) + RyR1(R615C) muscle. Therefore, our aim in this study was to utilize our pig model to understand how AMPKγ3(R200Q) and AMPK activation contribute to glycogen storage and metabolism in muscle. We selected and bred pigs in order to generate offspring with naturally occurring AMPKγ3(R200Q), RyR1(R615C), and AMPKγ3(R200Q) + RyR1(R615C) mutations, and also retained wild-type littermates (control). We assessed glycogen content and parameters of glycogen metabolism in longissimus muscle. Regardless of RyR1(R615C), AMPKγ3(R200Q) increased the glycogen content by approximately 70%. Activity of glycogen synthase (GS) without the allosteric activator glucose 6-phosphate (G6P) was decreased in AMPKγ3(R200Q) relative to all other genotypes, whereas both AMPKγ3(R200Q) and AMPKγ3(R200Q) + RyR1(R615C) muscle exhibited increased GS activity with G6P. Increased activity of GS with G6P was not associated with increased abundance of GS or hexokinase 2. However, AMPKγ3(R200Q) enhanced UDP-glucose pyrophosphorylase 2 (UGP2) expression approximately threefold. Although UGP2 is not generally considered a rate-limiting enzyme for glycogen synthesis, our model suggests that UGP2 plays an important role in increasing flux to glycogen synthase. Moreover, we have shown that the capacity for glycogen storage is more closely related to the AMPKγ3(R200Q) mutation than activity. PMID:27302990

  9. Design of High-Gain and Beam Steering Antennas Using a New Planar Folded-Line Metamaterial Structure

    Minh Thuy Le; Quoc Cuong Nguyen; Tan Phu Vuong

    2014-01-01

    In the last few years, there has been growing interest in employing metamaterials (MTMs) to enhance antenna gain. In this paper we proposed a novel structure of planar folded-line left-handed metamaterial (FL-LHM) and applied it to improve the gain of three 5.8 GHz microstrip antenna types: a circularly polarized patch antenna, an antenna array, and a beam steering antenna. The planar FL-LHM structure was designed based on transmission line analysis. Their scattering parameters were obtained ...

  10. DNA polymorphisms and transcript abundance of PRKAG2 and phosphorylated AMP-activated protein kinase in the rumen are associated with gain and feed intake in beef steers

    Beef steers with variation in feed efficiency phenotypes were evaluated previously on a high density SNP panel. Ten markers from rs110125325-rs41652818 on bovine chromosome 4 were associated with average daily gain (ADG). To identify the gene(s) in this 1.2Mb region responsible for variation in AD...

  11. Physical Activity and Dietary Behaviors Associated With Weight Gain and Impaired Glucose Tolerance Among Pregnant Latinas123

    Chasan-Taber, Lisa

    2012-01-01

    Pregnancy has been proposed as a critical period for the development of subsequent maternal overweight and/or obesity. Excessive gestational weight gain is, in turn, associated with maternal complications such as cesarean delivery, hypertension, preeclampsia, impaired glucose tolerance, and gestational diabetes mellitus. Although there is substantial evidence that targeting at-risk groups for type 2 diabetes prevention is effective if lifestyle changes are made, relatively little attention ha...

  12. An novel analog programmable power supply for active gain control of the Multi-Pixel Photon Counter (MPPC)

    Li, Zhengwei; Xu, Yupeng; Yan, Bo; Li, Yanguo; Lu, Xuefeng; Li, Xufang; Zhang, Shuo; Chang, Zhi; Li, Jicheng; Zhang, Yifei; Zhao, Jianling

    2016-01-01

    Silicon Photo-Multipliers (SiPM) are regarded as novel photo-detector to replace conventional Photo-Multiplier Tubes (PMTs). However, the breakdown voltage dependence on the ambient temperature results in a gain variation of $\\sim$3$\\% /^{\\circ} \\mathrm C$. This can severely limit the application of this device in experiments with wide range of operating temperature, especially in space telescope. An experimental setup in dark condition was established to investigate the temperature and bias voltage dependence of gain for the Multi-Pixel Photon Counter (MPPC), one type of the SiPM developed by Hamamatsu. The gain and breakdown voltage dependence on operating temperature of an MPPC can be approximated by a linear function, which is similar to the behavior of a zener diode. The measured temperature coefficient of the breakdown voltage is $(59.4 \\pm 0.4$ mV)$/^{\\circ} \\mathrm C$. According to this fact, a programmable power supply based on two zener diodes and an operational amplifier was designed with a positiv...

  13. A high conversion-gain Q-band InP DHBT subharmonic mixer using LO frequency doubler

    Johansen, Tom Keinicke; Vidkjær, Jens; Krozer, Viktor;

    2008-01-01

    (DHBT) technology using coplanar waveguide structures. To the best of our knowledge, this is the first demonstration of an SHM using InP DHBT technology at millimeter-wave frequencies. The measured results demonstrate a conversion gain of 10.3 dB at 45 GHz with an LO power of only 1 mW. The fundamental...

  14. High-throughput FACS-based mutant screen identifies a gain-of-function allele of the Fusarium graminearum adenylyl cyclase causing deoxynivalenol over-production.

    Blum, Ailisa; Benfield, Aurélie H; Stiller, Jiri; Kazan, Kemal; Batley, Jacqueline; Gardiner, Donald M

    2016-05-01

    Fusarium head blight and crown rot, caused by the fungal plant pathogen Fusarium graminearum, impose a major threat to global wheat production. During the infection, plants are contaminated with mycotoxins such as deoxynivalenol (DON), which can be toxic for humans and animals. In addition, DON is a major virulence factor during wheat infection. However, it is not fully understood how DON production is regulated in F. graminearum. In order to identify regulators of DON production, a high-throughput mutant screen using Fluorescence Activated Cell Sorting (FACS) of a mutagenised TRI5-GFP reporter strain was established and a mutant over-producing DON under repressive conditions identified. A gain-of-function mutation in the F. graminearum adenylyl cyclase (FAC1), which is a known positive regulator of DON production, was identified as the cause of this phenotype through genome sequencing and segregation analysis. Our results show that the high-throughput mutant screening procedure developed here can be applied for identification of fungal proteins involved in diverse processes. PMID:26932301

  15. Giant enhancement of optical high-order sideband generation and their control in a dimer of two cavities with gain and loss

    Li, Jiahui; Li, Jiahua; Xiao, Qian; Wu, Ying

    2016-06-01

    Parity-time (PT ) symmetric systems, which rely on the balanced gain-loss condition and render the Hamiltonian non-Hermitian, have provided a new platform to engineer effective light-matter interactions in recent years. Here we explore the high-order sideband features of the output fields obtained from a PT -symmetric optical system consisting of a passive nonlinear cavity coupled to an active linear cavity. By employing a perturbation technique, we derive analytic formulas used to determine the nonlinear transmission coefficient of optical second-order sideband in this structure. Using experimentally achievable parameters, it is clearly shown that the efficiency of the second-order sideband generation can be greatly enhanced in the PT -symmetric dimer, extremely in the vicinity of the transition point from unbroken- to broken-PT regimes. Moreover, we further analyzed the influences of the system parameters, including the photon-tunneling rate between two cavities, Kerr nonlinearity strength, and optical detuning, on the second-order sideband generation. Subsequently we investigate the higher-order sideband output spectrum by numerical simulations, where the sideband amplitude also is largely enhanced in the PT -symmetric arrangement, compared with the passive-passive double-cavity system. Our obtained results provide a new avenue for acquiring optical high-order sidebands and operating light, which may inspire further applications in chip-scale optical communications and optical frequency combs.

  16. Underrepresented minority high school and college students report STEM-pipeline sustaining gains after participating in the Loma Linda University Summer Health Disparities Research Program.

    Lorena M Salto

    Full Text Available An urgent need exists for graduate and professional schools to establish evidence-based STEM (science, technology, engineering, and math pipeline programs to increase the diversity of the biomedical workforce. An untapped yet promising pool of willing participants are capable high school students that have a strong STEM interest but may lack the skills and the guided mentoring needed to succeed in competitive STEM fields. This study evaluates and compares the impact of the Loma Linda University (LLU Summer Health Disparities Research Program on high school (HS and undergraduate (UG student participants. The primary focus of our summer research experience (SRE is to enhance the research self-efficacy of the participants by actively involving them in a research project and by providing the students with personalized mentoring and targeted career development activities, including education on health disparities. The results of our study show that our SRE influenced terminal degree intent and increased participant willingness to incorporate research into future careers for both the HS and the UG groups. The quantitative data shows that both the HS and the UG participants reported large, statistically significant gains in self-assessed research skills and research self-efficacy. Both participant groups identified the hands-on research and the mentor experience as the most valuable aspects of our SRE and reported increased science skills, increased confidence in science ability and increased motivation and affirmation to pursue a science career. The follow-up data indicates that 67% of the HS participants and 90% of the UG participants graduated from college with a STEM degree; for those who enrolled in graduate education, 61% and 43% enrolled in LLU, respectively. We conclude that structured SREs can be highly effective STEM strengthening interventions for both UG and HS students and may be a way to measurably increase institutional and biomedical

  17. Underrepresented minority high school and college students report STEM-pipeline sustaining gains after participating in the Loma Linda University Summer Health Disparities Research Program.

    Salto, Lorena M; Riggs, Matt L; Delgado De Leon, Daisy; Casiano, Carlos A; De Leon, Marino

    2014-01-01

    An urgent need exists for graduate and professional schools to establish evidence-based STEM (science, technology, engineering, and math) pipeline programs to increase the diversity of the biomedical workforce. An untapped yet promising pool of willing participants are capable high school students that have a strong STEM interest but may lack the skills and the guided mentoring needed to succeed in competitive STEM fields. This study evaluates and compares the impact of the Loma Linda University (LLU) Summer Health Disparities Research Program on high school (HS) and undergraduate (UG) student participants. The primary focus of our summer research experience (SRE) is to enhance the research self-efficacy of the participants by actively involving them in a research project and by providing the students with personalized mentoring and targeted career development activities, including education on health disparities. The results of our study show that our SRE influenced terminal degree intent and increased participant willingness to incorporate research into future careers for both the HS and the UG groups. The quantitative data shows that both the HS and the UG participants reported large, statistically significant gains in self-assessed research skills and research self-efficacy. Both participant groups identified the hands-on research and the mentor experience as the most valuable aspects of our SRE and reported increased science skills, increased confidence in science ability and increased motivation and affirmation to pursue a science career. The follow-up data indicates that 67% of the HS participants and 90% of the UG participants graduated from college with a STEM degree; for those who enrolled in graduate education, 61% and 43% enrolled in LLU, respectively. We conclude that structured SREs can be highly effective STEM strengthening interventions for both UG and HS students and may be a way to measurably increase institutional and biomedical workforce

  18. Measurements and simulations of the optical gain and anti-reflection coating modal reflectivity in quantum cascade lasers with multiple active region stacks

    We report spectrally resolved gain measurements and simulations for quantum cascade lasers (QCLs) composed of multiple heterogeneous stacks designed for broadband emission in the mid-infrared. The measurement method is first demonstrated on a reference single active region QCL based on a double-phonon resonance design emitting at 7.8 μm. It is then extended to a three-stack active region based on bound-to-continuum designs with a broadband emission range from 7.5 to 10.5 μm. A tight agreement is found with simulations based on a density matrix model. The latter implements exhaustive microscopic scattering and dephasing sources with virtually no fitting parameters. The quantitative agreement is furthermore assessed by measuring gain coefficients obtained by studying the threshold current dependence with the cavity length. These results are particularly relevant to understand fundamental gain mechanisms in complex semiconductor heterostructure QCLs and to move towards efficient gain engineering. Finally, the method is extended to the measurement of the modal reflectivity of an anti-reflection coating deposited on the front facet of the broadband QCL

  19. Measurements and simulations of the optical gain and anti-reflection coating modal reflectivity in quantum cascade lasers with multiple active region stacks

    Bidaux, Y.; Terazzi, R.; Bismuto, A.; Gresch, T.; Blaser, S.; Muller, A.; Faist, J.

    2015-09-01

    We report spectrally resolved gain measurements and simulations for quantum cascade lasers (QCLs) composed of multiple heterogeneous stacks designed for broadband emission in the mid-infrared. The measurement method is first demonstrated on a reference single active region QCL based on a double-phonon resonance design emitting at 7.8 μm. It is then extended to a three-stack active region based on bound-to-continuum designs with a broadband emission range from 7.5 to 10.5 μm. A tight agreement is found with simulations based on a density matrix model. The latter implements exhaustive microscopic scattering and dephasing sources with virtually no fitting parameters. The quantitative agreement is furthermore assessed by measuring gain coefficients obtained by studying the threshold current dependence with the cavity length. These results are particularly relevant to understand fundamental gain mechanisms in complex semiconductor heterostructure QCLs and to move towards efficient gain engineering. Finally, the method is extended to the measurement of the modal reflectivity of an anti-reflection coating deposited on the front facet of the broadband QCL.

  20. Novel design of inherently gain-flattened discrete highly nonlinear photonic crystal fiber Raman amplifier and dispersion compensation using a single pump in C-band.

    Varshney, Shailendra; Fujisawa, Takeshi; Saitoh, Kunimasa; Koshiba, Masanori

    2005-11-14

    In this paper, we report, for the first time, an inherently gain-flattened discrete highly nonlinear photonic crystal fiber (HNPCF) Raman amplifier (HNPCF-RA) design which shows 13.7 dB of net gain (with +/-0.85-dB gain ripple) over 28-nm bandwidth. The wavelength dependent leakage loss property of HNPCF is used to flatten the Raman gain of the amplifier module. The PCF structural design is based on W-shaped refractive index profile where the fiber parameters are well optimized by homely developed genetic algorithm optimization tool integrated with an efficient vectorial finite element method (V-FEM). The proposed fiber design has a high Raman gain efficiency of 4.88 W(-1) . km(-1) at a frequency shift of 13.1 THz, which is precisely evaluated through V-FEM. Additionally, the designed module, which shows ultra-wide single mode operation, has a slowly varying negative dispersion coefficient (-107.5 ps/nm/km at 1550 nm) over the operating range of wavelengths. Therefore, our proposed HNPCF-RA module acts as a composite amplifier with dispersion compensator functionality in a single component using a single pump. PMID:19503154

  1. Overexpression of Elafin in Ovarian Carcinoma Is Driven by Genomic Gains and Activation of the Nuclear Factor κB Pathway and Is Associated with Poor Overall Survival

    Adam Clauss

    2010-02-01

    Full Text Available Ovarian cancer is a leading cause of cancer mortality in women. The aim of this study was to elucidate whether whey acidic protein (WAP genes on chromosome 20q13.12, a region frequently amplified in this cancer, are expressed in serous carcinoma, the most common form of the disease. Herein, we report that a trio of WAP genes (HE4, SLPI, and Elafin is overexpressed and secreted by serous ovarian carcinomas. To our knowledge, this is the first report linking Elafin to ovarian cancer. Fluorescence in situ hybridization analysis of primary tumors demonstrates genomic gains of the Elafin locus in a majority of cases. In addition, a combination of peptidomimetics, RNA interference, and chromatin immunoprecipitation experiments shows that Elafin expression can be transcriptionally upregulated by inflammatory cytokines through activation of the nuclear factor κB pathway. Importantly, using a clinically annotated tissue microarray composed of late-stage, high-grade serous ovarian carcinomas, we show that Elafin expression correlates with poor overall survival. These results, combined with our observation that Elafin is secreted by ovarian tumors and is minimally expressed in normal tissues, suggest that Elafin may serve as a determinant of poor survival in this disease.

  2. The Effect of Length of Exposure to Computer-based Vocabulary Activities on Young Iranian EFL Learners’ Vocabulary Gain

    Karim Sadeghi; Masoumeh Dousti

    2014-01-01

    In recent years, research in the area of CALL and its role on teaching foreign languages has gained a strong foothold. This study was anattempt to explore the effectiveness of CALL technology in comparison to traditional book-based approach in teaching vocabulary to young Iranian EFL learners. As this study addressed young learners in an EFL context, it was supposed that time factor would play a crucial role in this regard. Hence, attending to the possible role of length of exposure to CALL t...

  3. Design of High-Gain and Beam Steering Antennas Using a New Planar Folded-Line Metamaterial Structure

    Minh Thuy Le

    2014-01-01

    Full Text Available In the last few years, there has been growing interest in employing metamaterials (MTMs to enhance antenna gain. In this paper we proposed a novel structure of planar folded-line left-handed metamaterial (FL-LHM and applied it to improve the gain of three 5.8 GHz microstrip antenna types: a circularly polarized patch antenna, an antenna array, and a beam steering antenna. The planar FL-LHM structure was designed based on transmission line analysis. Their scattering parameters were obtained using a numerical model; the negative effective permittivity and permeability were then calculated from these parameters for the assessment of negative refraction index region. The S11 and radiation patterns of three fabricated antennas were measured; these results matched well with the simulation. We observed that the gain was increased up to 3 dBi for all the antennas. In addition, we were also able to maintain the circular polarization as well as the steering of the antenna without changing its dimensions.

  4. Active video games as a tool to prevent excessive weight gain in adolescents: rationale, design and methods of a randomized controlled trial

    2014-01-01

    Background Excessive body weight, low physical activity and excessive sedentary time in youth are major public health concerns. A new generation of video games, the ones that require physical activity to play the games –i.e. active games- may be a promising alternative to traditional non-active games to promote physical activity and reduce sedentary behaviors in youth. The aim of this manuscript is to describe the design of a study evaluating the effects of a family oriented active game intervention, incorporating several motivational elements, on anthropometrics and health behaviors in adolescents. Methods/Design The study is a randomized controlled trial (RCT), with non-active gaming adolescents aged 12 – 16 years old randomly allocated to a ten month intervention (receiving active games, as well as an encouragement to play) or a waiting-list control group (receiving active games after the intervention period). Primary outcomes are adolescents’ measured BMI-SDS (SDS = adjusted for mean standard deviation score), waist circumference-SDS, hip circumference and sum of skinfolds. Secondary outcomes are adolescents’ self-reported time spent playing active and non-active games, other sedentary activities and consumption of sugar-sweetened beverages. In addition, a process evaluation is conducted, assessing the sustainability of the active games, enjoyment, perceived competence, perceived barriers for active game play, game context, injuries from active game play, activity replacement and intention to continue playing the active games. Discussion This is the first adequately powered RCT including normal weight adolescents, evaluating a reasonably long period of provision of and exposure to active games. Next, strong elements are the incorporating motivational elements for active game play and a comprehensive process evaluation. This trial will provide evidence regarding the potential contribution of active games in prevention of excessive weight gain in

  5. Single crystalline Er2O3:sapphire films as potentially high-gain amplifiers at telecommunication wavelength

    Single crystalline thin films of Er2O3, demonstrating efficient 1.5 μm luminescence of Er3+ at room temperature were grown on Al2O3 substrate by molecular beam epitaxy. The absorption coefficient at 1.536 μm was found to reach 270 cm−1 translating in a maximal possible gain of 1390 dBcm−1. In conjunction with the 10% higher refractive index as compared to Al2O3, this opens the possibility to use Er2O3:sapphire films as short-length waveguide amplifiers in telecommunication

  6. Improving proliferation resistance of high breeding gain generation 4 reactors using blankets composed of light water reactor waste

    Hellesen, C.; Grape, S.; Haakanson, A.; Jacobson Svaerd, S.; Jansson, P. [Division of Applied Nuclear Physics, Uppsala University, Aangstroemlaboratoriet Laegerhyddsvaegen 1, 751 20 Uppsala (Sweden)

    2013-07-01

    Fertile blankets can be used in fast reactors to enhance the breeding gain as well as the passive safety characteristics. However, such blankets typically result in the production of weapons grade plutonium. For this reason they are often excluded from Generation IV reactor designs. In this paper we demonstrate that using blankets manufactured directly from spent light water (LWR) reactor fuel it is possible to produce a plutonium product with non-proliferation characteristics on a par with spent LWR fuel of 30-50 MWd/kg burnup. The beneficial breeding and safety characteristics are retained. (authors)

  7. Solidification of highly active wastes

    Final reports are presented on work on the following topics: glass technology; enhancement of off-gas aerosol collection; formation and trapping of volatile ruthenium; volatilisation of caesium, technetium and tellurium in high-level waste vitrification; deposition of ruthenium; and calcination of high-level waste liquors. (author)

  8. Increasing weight-bearing physical activity and calcium-rich foods to promote bone mass gains among 9–11 year old girls: outcomes of the Cal-Girls study

    Hannan Peter

    2005-07-01

    Full Text Available Abstract Background A two-year, community-based, group-randomized trial to promote bone mass gains among 9–11 year-old girls through increased intake of calcium-rich foods and weight-bearing physical activity was evaluated. Methods Following baseline data collection, 30 5th-grade Girl Scout troops were randomized to a two-year behavioral intervention program or to a no-treatment control group. Evaluations were conducted at baseline, one year, and two years. Measures included bone mineral content, density, and area (measured by DXA, dietary calcium intake (24-hour recall, and weight-bearing physical activity (physical activity checklist interview. Mixed-model regression was used to evaluate treatment-related changes in bone mineral content (g for the total body, lumbar spine (L1-L4, proximal femur, one-third distal radius, and femoral neck. Changes in eating and physical activity behavioral outcomes were examined. Results Although the intervention was implemented with high fidelity, no significant intervention effects were observed for total bone mineral content or any specific bone sites. Significant intervention effects were observed for increases in dietary calcium. No significant intervention effects were observed for increases in weight-bearing physical activity. Conclusion Future research needs to identify the optimal dosage of weight-bearing physical activity and calcium-rich dietary behavior change required to maximize bone mass gains in pre-adolescent and adolescent girls.

  9. High-power 1.25 µm InAs QD VECSEL based on resonant periodic gain structure

    Albrecht, Alexander R.; Rotter, Thomas J.; Hains, Christopher P.; Stintz, Andreas; Xin, Guofeng; Wang, Tsuei-Lian; Kaneda, Yushi; Moloney, Jerome V.; Malloy, Kevin J.; Balakrishnan, Ganesh

    2011-03-01

    We compare an InAs quantum dot (QD) vertical external-cavity surface-emitting laser (VECSEL) design consisting of 4 groups of 3 closely spaced QD layers with a resonant periodic gain (RPG) structure, where each of the 12 QD layers is placed at a separate field antinode. This increased the spacing between the QDs, reducing strain and greatly improving device performance. For thermal management, the GaAs substrate was thinned and indium bonded to CVD diamond. A fiber-coupled 808 nm diode laser was used as pump source, a 1% transmission output coupler completed the cavity. CW output powers over 4.5 W at 1250 nm were achieved.

  10. Experimental Setup and Commissioning of a Test Facility for Gain Evaluation of Microchannel-Plate Photomultipliers in High Magnetic Field at Jefferson Lab

    Bringley, Eric; Cao, Tongtong; Ilieva, Yordonka; Nadel-Turonski, Pawel; Park, Kijun; Zorn, Carl

    2014-09-01

    At the Thomas Jefferson National Accelerator Facility (JLab) a research and development project for a Detector of Internally-Reflected Cherenkov light for the upcoming Electron Ion Collider is underway. One goal is the development of a compact readout camera that can operate in high magnetic fields. Small-size photon sensors, such as Microchannel-Plate Photomultipliers (MCP-PMT), are key components of the readout. Here we present our work to set up and commission a dedicated test facility at JLab where MCP-PMT gain is evaluated in magnetic fields of up to 5 T, and to develop a test procedure and analysis software to determine the gain. We operate the setup in a single-photon mode, where a light-emitting diode delivers photons to the sensor's photocathode. The PMT spectrum is measured with a flash Analog-to-Digital converter (fADC). We model the spectrum as a sum of an exponential background and a convolution of Poisson and Gaussian distributions of the pedestal and multiple photoelectron peaks, respectively. We determine the PMT's gain from the position of the single-photoelectron peak obtained by fitting the fADC spectrum to the model. Our gain uncertainty is <10%. The facility is now established and will have a long-lasting value for sensor tests and beyond-nuclear-physics applications.

  11. A Wideband High-Gain Dual-Polarized Slot Array Patch Antenna for WiMAX Applications in 5.8 GHz

    Amir Reza Dastkhosh

    2012-01-01

    Full Text Available A low-cost, easy-to-fabricate, wideband and high-gain dual-polarized array antenna employing an innovative microstrip slot patch antenna element is designed and fabricated. The design parameters of the antenna are optimized using commercial softwares (Microwave Office and Zeland IE3D to get the suitable -parameters and radiation patterns. Finally, the simulation results are compared to the experimental ones and a good agreement is demonstrated. The antenna has an approximately bandwidth of 14% (5.15–5.9 GHz which covers Worldwide Interoperability Microwave Access (WiMAX/5.8. It also has the peak gain of 26 dBi for both polarizations and high isolation between two ports over a wide bandwidth.

  12. A key issue for next generation diode pumped solid state laser drivers for IFE: amplified spontaneous emission in large size, high gain Yb:YAG slabs

    Albach, D; Assemat, F; Bahbah, S; Bourdet, G; Chanteloup, J-C; Piatti, P; Pluvinage, M; Vincent, B; Touze, G L [LULI, Ecole Polytechnique, CNRS, CEA, UPMC, Route de Saclay, 91128, Palaiseau (France)], E-mail: daniel.albach@polytechnique.edu

    2008-05-15

    Amplified Spontaneous Emission (ASE) is one of the key issues to be addressed when designing a diode pumped laser with a large transverse size / high gain amplifier. A 3D model using the Monte-Carlo method computing the effect of ASE in the quasi-three-level system of Yb{sup 3+}:YAG is actually under development for the Lucia-project. This work is performed within the Lucia project.

  13. A key issue for next generation diode pumped solid state laser drivers for IFE: amplified spontaneous emission in large size, high gain Yb:YAG slabs

    Amplified Spontaneous Emission (ASE) is one of the key issues to be addressed when designing a diode pumped laser with a large transverse size / high gain amplifier. A 3D model using the Monte-Carlo method computing the effect of ASE in the quasi-three-level system of Yb3+:YAG is actually under development for the Lucia-project. This work is performed within the Lucia project

  14. Ultrahigh-sensitivity high-linearity photodetection system using a low-gain avalanche photodiode with an ultralow-noise readout circuit

    Akiba, Makoto; Fujiwara, Mikio; Sasaki, Masahide

    2005-01-01

    A highly sensitive photodetection system with a detection limit of 1 photon/s was developed. This system uses a commercially available 200-mm-diameter silicon avalanche photodiode (APD) and an in-house-developed ultralow-noise readout circuit, which are both cooled to 77 K. When the APD operates at a low gain of about 10, it has a high-linearity response to the number of incident photons and a low excess noise factor. The APD also has high quantum efficiency and a dark current of less than 1 ...

  15. Amorphous silicon germanium carbide photo sensitive bipolar junction transistor with a base-contact and a continuous tunable high current gain

    Bablich, A., E-mail: andreas.bablich@uni-siegen.de [Department of Electrical and Computer Engineering, Institute for Microsystem Technologies, University of Siegen, Hoelderlinstrasse 3, 57076 Siegen (Germany); Merfort, C., E-mail: merfort@imt.e-technik.uni-siegen.de [Department of Electrical and Computer Engineering, Institute for Microsystem Technologies, University of Siegen, Hoelderlinstrasse 3, 57076 Siegen (Germany); Eliasz, J., E-mail: jacek.eliasz@student.uni-siegen.de [Department of Electrical and Computer Engineering, Institute for Microsystem Technologies, University of Siegen, Hoelderlinstrasse 3, 57076 Siegen (Germany); Schäfer-Eberwein, H., E-mail: heiko.schaefer@uni-siegen.de [Department of Electrical and Computer Engineering, Institute of High Frequency and Quantum Electronics, University of Siegen, Hoelderlinstrasse 3, 57076 Siegen (Germany); Haring-Bolivar, P., E-mail: peter.haring@uni-siegen.de [Department of Electrical and Computer Engineering, Institute of High Frequency and Quantum Electronics, University of Siegen, Hoelderlinstrasse 3, 57076 Siegen (Germany); Boehm, M., E-mail: markus.boehm@uni-siegen.de [Department of Electrical and Computer Engineering, Institute for Microsystem Technologies, University of Siegen, Hoelderlinstrasse 3, 57076 Siegen (Germany)

    2014-05-02

    , the device presented in this paper obtains no optical gain with an incident light power of 0.31 μW and 578 nm wavelength. The PS-BJT exhibits promising characteristics with a maximum current density greater than 65 μA μm{sup −1} and a tunable high current gain β. Possible applications exist in fields of control and drive circuits, in display and image devices, in photo interrupters, in photo sensitive matrices or in optoelectronic switches. - Highlights: • Current controllable a-Si:H phototransistor • Controllable high current gain • Current and phototunable transistor.

  16. Amorphous silicon germanium carbide photo sensitive bipolar junction transistor with a base-contact and a continuous tunable high current gain

    light power of 0.31 μW and 578 nm wavelength. The PS-BJT exhibits promising characteristics with a maximum current density greater than 65 μA μm−1 and a tunable high current gain β. Possible applications exist in fields of control and drive circuits, in display and image devices, in photo interrupters, in photo sensitive matrices or in optoelectronic switches. - Highlights: • Current controllable a-Si:H phototransistor • Controllable high current gain • Current and phototunable transistor

  17. A C-band 55%PAE high gain two-stage power amplifier based on AlGaN/GaN HEMT

    郑佳欣; 马晓华; 卢阳; 赵博超; 张宏鹤; 张濛; 曹梦逸; 郝跃

    2015-01-01

    A C-band high efficiency and high gain two-stage power amplifier based on AlGaN/GaN high electron mobility transistor (HEMT) is designed and measured in this paper. The input and output impedances for the optimum power-added efficiency (PAE) are determined at the fundamental and 2nd harmonic frequency ( f0 and 2 f0). The harmonic manipulation networks are designed both in the driver stage and the power stage which manipulate the second harmonic to a very low level within the operating frequency band. Then the inter-stage matching network and the output power combining network are calculated to achieve a low insertion loss. So the PAE and the power gain is greatly improved. In an operation frequency range of 5.4 GHz–5.8 GHz in CW mode, the amplifier delivers a maximum output power of 18.62 W, with a PAE of 55.15%and an associated power gain of 28.7 dB, which is an outstanding performance.

  18. Designing Gain- and Loss-Framed Messages to Increase Physical Activity among University Students Living in two Different Cultures

    Pelin Ozgur Polat

    2015-10-01

    The primary aim of this project is to gather information through using different methods and investigate the determinants of message persuasiveness in university students from the British and Turkish cultures in order to design effective physical activity messages leading intention, attitude and behaviour change. The results of the finalized studies showed the importance of using both qualitative and quantitative methods in message design process.

  19. Auto-digital gain balancing: a new detection scheme for high-speed chemical species tomography of minor constituents

    In many dynamic gas-phase reaction processes, there is great interest to measure the distribution of minor constituents, i.e. −3 by volume (1000 ppm). One such case is the after-treatment of automotive gasoline engine exhaust by catalytic conversion, where a characteristic challenge is to image the distribution of 10 ppm (average) of carbon monoxide (CO) at 1000 frames per second across a 50 mm diameter exhaust pipe; this particular problem has been pursued as a case study. In this paper, we present a novel electronic scheme that achieves the required measurement of around 10−3 absorption with 10−4 precision at kHz bandwidth. This was not previously achievable with any known technology. We call the new scheme Auto-Digital Gain Balancing. It is amenable to replication for many simultaneous measurement channels, and it permits simultaneous measurement of multiple species, in some circumstances. Experimental demonstrations are presented in the near-infrared. In single scans of a tunable diode laser, measurements of both CO and CO2 have been made with 20 dB signal-to-noise ratio at peak absorption. This work paves the way for chemical species tomography of minor constituents in many dynamic gas-phase systems

  20. Gaining Insights from a Case Study of High School Student Performance in Dual-Credit College Chemistry Courses

    White, Jacob; Hopkins, Robert; Shockley, Denise

    2014-01-01

    This report describes student performance in a state-level initiative that provided first-year college coursework in chemistry to high school students. Upon successful completion of the coursework, students received both high school and college credit. In this initiative, high school teachers team taught college-level chemistry courses in…

  1. Vitrification of high active waste

    The main stream of high level radioactive materials generated as wastes by the reprocessing of spent nuclear fuel is composed of fission products solutions. The storage of these liquids has been operated until now in stainless steel tanks almost everywhere. From a general standpoint, it is now assumed that these solutions, in which long-life actinides are also present, must be solidified owing to the hazards related to a long term disposal. Vitrification has generally been taken more into consideration than other processes owing to a relatively simple implementation and mainly because glass is a medium flexible enough to house the various elements bound to be present in the radioactive liquids without inducing drastic changes in the physicochemical properties. Among these properties a particular attention is paid to the ones connected to the fabrication: corrosiveness, volatilization, viscosity as well as to the interim storage and long term disposal: thermal stability, chemical stability versus #betta# #betta# and α irradiation including the subsequent effects of helium build up. Investigations in those fields have been carried out principally on borosilicate and aluminoborosilicate glasses. The manufacture techniques under development are numerous. Some of them are continuous processes, other are batch ones. Both can involve either a one stage or a two stage fabrication. The most advanced technique is a 2 stages continuous process involving calcination in a rotary tube and vitrification in a metallic melter. (orig./HW)

  2. High exposure hardware removal activity readiness evaluation

    This document comprises the Readiness Evaluation Plan for the High Exposure Rate Hardware (HERH) Removal Activity planned for the N Basin area at the Hanford Reservation in Richland Washington. This activity will consist of collecting hardware, depositing hardware in stainless-steel fuel element storage baskets, placing baskets in specially fabricated steel grout pipe, and encasing the contents in a high-slump grout

  3. Laser diode-pumped dual-cavity high-power fiber laser emitting at 1150  nm employing hybrid gain.

    Chen, Yizhu; Xiao, Hu; Xu, Jiangming; Leng, Jinyong; Zhou, Pu

    2016-05-10

    We demonstrate a laser diode-pumped dual-cavity high-power fiber laser emitting at 1150 nm. The laser employs Yb and Raman gains simultaneously. The fiber laser with a simple structure achieves high-efficiency operation while efficiently suppressing the amplified spontaneous emission and parasitic oscillation. The maximum output power at 1150 nm is 110.8 W, with an optical-to-optical efficiency of 57%. Further power scaling at 1150 nm is expected with the optimization of the system design. PMID:27168299

  4. A High-Gain Three-Port Power Converter with Fuel Cell, Battery Sources and Stacked Output for Hybrid Electric Vehicles and DC-Microgrids

    Ching-Ming Lai; Ming-Ji Yang

    2016-01-01

    This paper proposes a novel high-gain three-port power converter with fuel cell (FC), battery sources and stacked output for a hybrid electric vehicle (HEV) connected to a dc-microgrid. In the proposed power converter, the load power can be flexibly distributed between the input sources. Moreover, the charging or discharging of the battery storage device can be controlled effectively using the FC source. The proposed converter has several outputs in series to achieve a high-voltage output, wh...

  5. Three Months of High-Fructose Feeding Fails to Induce Excessive Weight Gain or Leptin Resistance in Mice

    Tillman, Erik J.; Morgan, Donald A.; Kamal Rahmouni; Swoap, Steven J.

    2014-01-01

    High-fructose diets have been implicated in obesity via impairment of leptin signaling in humans and rodents. We investigated whether fructose-induced leptin resistance in mice could be used to study the metabolic consequences of fructose consumption in humans, particularly in children and adolescents. Male C57Bl/6 mice were weaned to a randomly assigned diet: high fructose, high sucrose, high fat, or control (sugar-free, low-fat). Mice were maintained on their diets for at least 14 weeks. Wh...

  6. Comparative Study on  Paralleled vs. Scaled Dc-dc Converters  in High Voltage Gain Applications

    Klimczak, Pawel; Munk-Nielsen, Stig

    2008-01-01

    Today power converters are present in many commercial, medical and industrial applications. A lot of them are high power and high current applications. In order to increase power handling capability several transistors or diodes are paralleled often. However such paralleling may lead to converter...

  7. A gain-coefficient switched Alexandrite laser

    Lee, Chris J.; van der Slot, Peter J. M.; Boller, Klaus-J.

    2012-01-01

    We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.

  8. A gain-coefficient switched Alexandrite laser

    Lee, C. J.; van der Slot, P. J. M.; Boller, K. J.

    2013-01-01

    We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ

  9. Gain-of-function analogs of the pore-forming peptide melittin selected by orthogonal high-throughput screening

    Krauson, Aram J.; He, Jing; Wimley, William C.

    2012-01-01

    We recently developed an orthogonal, high-throughput assay to identify peptides that self-assemble into potent, equilibrium pores in synthetic lipid bilayers. Here, we use this assay as a high-throughput screen to select for highly potent pore-forming peptides from a 7,776-member rational combinatorial peptide library based on the sequence of the natural pore-forming peptide toxin melittin. In the library we varied ten critical residues in the melittin sequence, chosen to test specific struct...

  10. Influence of RZ and NRZ signal format on the high-speed performance of gain-clamped semiconductor optical amplifiers

    Fjelde, Tina; Wolfson, David; Kloch, Allan

    2000-01-01

    High-speed experiments show that the influence from the limited relaxation frequency of GC-SOAs that severely degrades the performance for NRZ signals is reduced by using RZ signals, thus resulting in a higher input power dynamic range.......High-speed experiments show that the influence from the limited relaxation frequency of GC-SOAs that severely degrades the performance for NRZ signals is reduced by using RZ signals, thus resulting in a higher input power dynamic range....

  11. Significant progression of load on the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using the Anatoly Gravitational System, in a 10-week training period

    Burke DT

    2013-10-01

    Full Text Available David T Burke,1 David Tran,1 Di Cui,1 Daniel P Burke,2 Samir Al-Adawi,3 Atsu SS Dorvlo41Emory University Medical School, Atlanta, GA, USA; 2Georgia College and State University, GA, USA; 3Department of Behavioral Medicine, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman; 4Department of Mathematics and Statistics, College of Science, Sultan Qaboos University, Muscat, OmanAbstract: In an age of increasing numbers of lifestyle diseases and plasticity of longevity, exercise and weight training have been increasingly recognized as both preventing and mitigating the severity of many illnesses. This study was designed to determine whether significant weight-lifting gains could be realized through the Anatoly Gravitational System. Specifically, this study sought to determine whether this once-weekly weight-training system could result in significant weekly strength gains during a 10-week training period. A total of 50 participants, ranging in age from 17 to 67 years, completed at least 10 weekly 30-minute training sessions. The results suggest participants could, on average, double their weight-lifting capacity within 10 sessions. This preliminary study, which would require further scrutiny, suggests the Anatoly Gravitational System provides a rather unique opportunity to load the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using only short weekly training sessions. More studies are warranted to scrutinize these findings.Keywords: Anatoly Gravitational System, weight training, musculoskeletal system

  12. Caplanar Stripline Fed Triple-Band High-Gain Microstrip Antenna%共面带状线馈电三频高增益微带天线

    周鋆; 杨雪霞; 吕艳青

    2011-01-01

    介绍一种工作于2.4,3.5和5.8 GHz的三频微带天线,采用共面带状线(coplanar stripline,CPS)馈电,结构简单且具有较高的增益.采用在菱形环结构中添加小环的方式实现多频工作,并在介质基板底部添加反射板以提高整体增益.为实现实测和满足更多应用需求,设计CPS至微带线的巴伦.实测结果与仿真结果较一致,均达到实际应用的要求,并且各频点增益都在10dB以上.%A microstrip antenna fed by a coplanar stripline (CPS) working at 2.4, 3.5 and 5.8 GHz with a simple structure and a high gain is proposed. Multi-frequency operation is realized by introducing a pair of small hoops in the center of the rhombic structure. The gain is improved by placing a metal reflector beneath the substrate. A CPS to microstrip Balun is designed for measurements and more applications.The measuring results agree well with simulation, which meet the demand of practical applications. Gains of all operating frequencies are higher than 10 dB.

  13. High-fat-diet-induced weight gain ameliorates bone loss without exacerbating AβPP processing and cognition in female APP/PS1 mice

    Yunhua ePeng

    2014-08-01

    Full Text Available Osteoporosis is negatively correlated with body mass, whereas both osteoporosis and weight loss occur at higher incidence during the progression of Alzheimer’s disease (AD than the age-matched non-dementia individuals. Given that there is no evidence that overweight associated with AD-type cognitive dysfunction, we hypothesized that moderate weight gain might have a protective effect on the bone loss in AD without exacerbating cognitive dysfunction. In the present study, feeding a high-fat-diet (HFD, 45% calorie from fat to female APP/PS1 transgenic mice, an AD animal model, induced weight gain. The bone mineral density, microarchitecture, and biomechanical properties of the femurs were then evaluated. The results showed that the middle-aged female APP/PS1 transgenic mice were susceptible to osteoporosis of the femoral bones and that weight gain significantly enhanced bone mass and mechanical properties. Notably, HFD was not detrimental to brain insulin signaling and AβPP processing, as well as to exploration ability and working, learning and memory performance of the transgenic mice measured by T maze and water maze, compared with the mice fed a normal fat diet (10% calorie from fat. In addition, the circulating levels of leptin but not estradiol were remarkably elevated in HFD-treated mice. These results suggest that a body weight gain induced by the HFD feeding regimen significantly improved bone mass in female APP/PS1 mice with no detriments to exploration ability and spatial memory, most likely via the action of elevated circulating leptin.

  14. Coupled Isothermal Continuous Preferential Crystallization (CIC-PC) – A Novel Promising Technology for Gaining Pure Enantiomers with High Productivity

    Seidel-Morgenstern, A.; M. Elsner

    2010-01-01

    The recognition of differences in the pharmacological activity of enantiomeric molecules has induced the necessity to administer them as isolated enantiomers in order to ensure the desired optimum therapeutic effect. Driven by the becoming more and more restrictive policy of regulatory authorities such as US Food and Drug Administration and the EU Committee for Proprietary Medical Products the production of pure enantiomers is considerably increasing in several industrial branches, e. g. phar...

  15. High effective silica fume alkali activator

    Vladimír Živica

    2004-04-01

    Growing demands on the engineering properties of cement based materials and the urgency to decrease unsuitable ecologic impact of Portland cement manufacturing represent significant motivation for the development of new cement corresponding to these aspects. One category represents prospective alkali activated cements. A significant factor influencing their properties is alkali activator used. In this paper we present a new high effective alkali activator prepared from silica fume and its effectiveness. According to the results obtained this activator seems to be more effective than currently used activators like natrium hydroxide, natrium carbonate, and water glass.

  16. Antagonism of T-type calcium channels inhibits high-fat diet–induced weight gain in mice

    Uebele, Victor N.; Gotter, Anthony L.; Nuss, Cindy E.; Kraus, Richard L.; Doran, Scott M.; Garson, Susan L.; Reiss, Duane R.; Li, Yuxing; Barrow, James C.; Reger, Thomas S.; Yang, Zhi-Qiang; Ballard, Jeanine E.; Tang, Cuyue; Metzger, Joseph M.; Wang, Sheng-Ping

    2009-01-01

    The epidemics of obesity and metabolic disorders have well-recognized health and economic burdens. Pharmacologic treatments for these diseases remain unsatisfactory with respect to both efficacy and side-effect profiles. Here, we have identified a potential central role for T-type calcium channels in regulating body weight maintenance and sleep. Previously, it was shown that mice lacking CaV3.1 T-type calcium channels have altered sleep/wake activity. We found that these mice were also resist...

  17. Impact of Korean pine nut oil on weight gain and immune responses in high-fat diet-induced obese mice

    Park, Soyoung; Lim, Yeseo; Shin, Sunhye; Han, Sung Nim

    2013-01-01

    Korean pine nut oil (PNO) has been reported to have favorable effects on lipid metabolism and appetite control. We investigated whether PNO consumption could influence weight gain, and whether the PNO-induced effect would result in an improvement of immune function in high-fat diet (HFD)-induced obese mice. C57BL/6 mice were fed control diets with 10% energy fat from either PNO or soybean oil (SBO), or HFDs with 45% energy fat from 10% PNO or SBO and 35% lard, 20% PNO or SBO and 25% lard, or ...

  18. Repetition-rate-selectable high-speed optical gating in a VO2 thin film based on gain modulation of optical amplifier

    In this research, we investigated the dependence of the saturation-induced gain modulation (SIGM) on the modulation frequency of the input signal in an erbium-doped fiber amplifier (EDFA). By finding and incorporating the modulation frequency invariance of the SIGM realizable within some frequency range, we demonstrated a repetition-rate-selectable high-speed optical gating in two-terminal electrical devices based on vanadium-dioxide thin films. In the implemented optical gating system, the repetition rate could be freely chosen as an arbitrary frequency between 0.27 and 10 kHz without any degradation of the gating speed and the signal-to-noise ratio.

  19. High-Resolution Three-Dimensional Structural Data Quantify the Impact of Photoinhibition on Long-Term Carbon Gain in Wheat Canopies in the Field.

    Burgess, Alexandra J; Retkute, Renata; Pound, Michael P; Foulkes, John; Preston, Simon P; Jensen, Oliver E; Pridmore, Tony P; Murchie, Erik H

    2015-10-01

    Photoinhibition reduces photosynthetic productivity; however, it is difficult to quantify accurately in complex canopies partly because of a lack of high-resolution structural data on plant canopy architecture, which determines complex fluctuations of light in space and time. Here, we evaluate the effects of photoinhibition on long-term carbon gain (over 1 d) in three different wheat (Triticum aestivum) lines, which are architecturally diverse. We use a unique method for accurate digital three-dimensional reconstruction of canopies growing in the field. The reconstruction method captures unique architectural differences between lines, such as leaf angle, curvature, and leaf density, thus providing a sensitive method of evaluating the productivity of actual canopy structures that previously were difficult or impossible to obtain. We show that complex data on light distribution can be automatically obtained without conventional manual measurements. We use a mathematical model of photosynthesis parameterized by field data consisting of chlorophyll fluorescence, light response curves of carbon dioxide assimilation, and manual confirmation of canopy architecture and light attenuation. Model simulations show that photoinhibition alone can result in substantial reduction in carbon gain, but this is highly dependent on exact canopy architecture and the diurnal dynamics of photoinhibition. The use of such highly realistic canopy reconstructions also allows us to conclude that even a moderate change in leaf angle in upper layers of the wheat canopy led to a large increase in the number of leaves in a severely light-limited state. PMID:26282240

  20. A High Gain & Wide Band Rectangular Microstrip Patch Antenna loaded with “Interconnected SRR” Metamaterial Structure

    Pramod Singhal; Bimal Garg

    2012-01-01

    Communication applications require wide band and highly directive planner antennas. For such requirement this work deals with the analysis and simulation of a rectangular microstrip patch antenna loaded with “INTERCONNECTED SRR” metamaterial structure at a height of 3.2mm from the ground plane. The work also investigates the potential properties of the proposed metamaterial structure. The proposed Antenna is designed at a operating frequency of 2.75GHz to meet S-Band (2-4GHz) applications. By...

  1. Co-regulation analysis of closely linked genes identifies a highly recurrent gain on chromosome 17q25.3 in prostate cancer

    Transcriptional profiling of prostate cancer (PC) has unveiled new markers of neoplasia and allowed insights into mechanisms underlying this disease. Genomewide analyses have also identified new chromosomal abnormalities associated with PC. The combination of both classes of data for the same sample cohort might provide better criteria for identifying relevant factors involved in neoplasia. Here we describe transcriptional signatures identifying distinct normal and tumoral prostate tissue compartments, and the inference and demonstration of a new, highly recurrent copy number gain on chromosome 17q25.3. We have applied transcriptional profiling to tumoral and non-tumoral prostate samples with relatively homogeneous epithelial representations as well as pure stromal tissue from peripheral prostate and cultured cell lines, followed by quantitative RT-PCR validations and immunohistochemical analysis. In addition, we have performed in silico colocalization analysis of co-regulated genes and validation by fluorescent in situ hybridization (FISH). The transcriptomic analysis has allowed us to identify signatures corresponding to non-tumoral luminal and tumoral epithelium, basal epithelial cells, and prostate stromal tissue. In addition, in silico analysis of co-regulated expression of physically linked genes has allowed us to predict the occurrence of a copy number gain at chromosomal region 17q25.3. This computational inference was validated by fluorescent in situ hybridization, which showed gains in this region in over 65% of primary and metastatic tumoral samples. Our approach permits to directly link gene copy number variations with transcript co-regulation in association with neoplastic states. Therefore, transcriptomic studies of carefully selected samples can unveil new diagnostic markers and transcriptional signatures highly specific of PC, and lead to the discovery of novel genomic abnormalities that may provide additional insights into the causes and mechanisms

  2. Ultrahigh-sensitivity high-linearity photodetection system using a low-gain avalanche photodiode with an ultralow-noise readout circuit

    Akiba, M; Sasaki, M; Akiba, Makoto; Fujiwara, Mikio; Sasaki, Masahide

    2005-01-01

    A highly sensitive photodetection system with a detection limit of 1 photon/s was developed. This system uses a commercially available 200-mm-diameter silicon avalanche photodiode (APD) and an in-house-developed ultralow-noise readout circuit, which are both cooled to 77 K. When the APD operates at a low gain of about 10, it has a high-linearity response to the number of incident photons and a low excess noise factor. The APD also has high quantum efficiency and a dark current of less than 1 e/s at 77 K. This photodetection system will shorten the measurement time and enable higher spatial and wavelength resolution for near-field scanning optical microscopes.

  3. Strongly asymmetric waveguide laser diodes for high brightness picosecond optical pulses generation by gain switching at GHz repetition rates

    Rate equations analysis, supported by travelling wave simulations, is used to show that a diode laser design with a very low (<1%) confinement factor is optimal for generating streams of high energy optical pulses for nonlinear applications by large-signal modulation with both existing and potentially improved ac current generators. An asymmetric waveguide laser design is proposed to realize this low confinement factor while simultaneously maintaining good beam properties in a single transverse mode. The rate equations model complemented by transport equations is used to quantify the effects of transport in the broad optical confinement layer(s) on the laser dynamics, and it is shown that in the proposed laser construction the detrimental effects of transport are weak. (paper)

  4. Mechanical design, materials selection, fabrication and assembly of ultraclean, high-gain Nd: glass disk laser amplifiers

    A major system design constraint is maximization of focusable peak power per dollar. This yields disk amplifiers that have high internal radiation densities (to approximately 20 J/cm2) from the flashlamps. This flashlamp radiation interacts with particulates (some of which it produces) to form up to three types of opaque spot that introduce diffraction rings into the laser beam. The energy in these rings is not useable, at best, and causes extensive component damage, at worst. The particles that cause evanescent opacities can be eliminated by using appropriate clean rooms and associated techniques during assembly. Most of the particles that cause permanent opacities can be eliminated by eliminating rubbing, such as occurs during mating of threaded parts. We have achieved the best results with 304 stainless steel that, after part fabrication, is buffed, then electropolished, then chemically polished

  5. The Study of Electromagnetic Wave Propogation in Photonic Crystals Via Planewave Based Transfer (Scattering) Matrix Method with Active Gain Material Applications

    Ming LI

    2007-12-01

    In this dissertation, a set of numerical simulation tools are developed under previous work to efficiently and accurately study one-dimensional (1D), two-dimensional(2D), 2D slab and three-dimensional (3D) photonic crystal structures and their defects effects by means of spectrum (transmission, reflection, absorption), band structure (dispersion relation), and electric and/or magnetic fields distribution (mode profiles). Furthermore, the lasing property and spontaneous emission behaviors are studied when active gain materials are presented in the photonic crystal structures. Various physical properties such as resonant cavity quality factor, waveguide loss, propagation group velocity of electromagnetic wave and light-current curve (for lasing devices) can be obtained from the developed software package.

  6. A High-Gain Three-Port Power Converter with Fuel Cell, Battery Sources and Stacked Output for Hybrid Electric Vehicles and DC-Microgrids

    Ching-Ming Lai

    2016-03-01

    Full Text Available This paper proposes a novel high-gain three-port power converter with fuel cell (FC, battery sources and stacked output for a hybrid electric vehicle (HEV connected to a dc-microgrid. In the proposed power converter, the load power can be flexibly distributed between the input sources. Moreover, the charging or discharging of the battery storage device can be controlled effectively using the FC source. The proposed converter has several outputs in series to achieve a high-voltage output, which makes it suitable for interfacing with the HEV and dc-microgrid. On the basis of the charging and discharging states of the battery storage device, two power operation modes are defined. The proposed power converter comprises only one boost inductor integrated with a flyback transformer; the boost and flyback circuit output terminals are stacked to increase the output voltage gain and reduce the voltage stress on the power devices. This paper presents the circuit configuration, operating principle, and steady-state analysis of the proposed converter, and experiments conducted on a laboratory prototype are presented to verify its effectiveness.

  7. Chrysobalanus icaco L. Leaves Normalizes Insulin Sensitivity and Blood Glucose and Inhibits Weight Gain in High-Fat Diet-Induced Obese Mice.

    White, Pollyanna A S; Araújo, Jessica M D; Cercato, Luana M; Souza, Lucas A; Barbosa, Ana Paula Oliveira; Quintans-Junior, Lucindo José; Machado, Ubiratan F; Camargo, Enilton A; Brito, Luciana C; Santos, Marcio Roberto V

    2016-02-01

    Chrysobalanus icaco L. is a medicinal plant present in the Brazilian coastline and known for its hypoglicemic and antioxidant properties. Here, we assessed the beneficial metabolic effects of the aqueous extract of C. icaco (AECI) leaves in diet-induced obese mice. Swiss mice were fed standard chow (SC used as controls) or high-fat diet (HFD) to induce obesity. After 10 weeks, mice on each diet were divided into two groups with one group used as control while the other group treated with AECI for 4 weeks resulting in four groups of mice: SC; SC treated with AECI (SC + AECI); HFD; and HFD treated with AECI (HFD + AECI). AECI was administered drinking water at about 200 mg/kg. AECI was able to normalize insulin (13,682 ± 1090 vs. 9828 ± 485 AU, P < .05) and fasting blood glucose (192.8 ± 14.2 vs. 132.3 ± 6.4 mg/dL, P < .05) and inhibit weight gain (39 ± 5.7%) and fat storage in liver (72.60 ± 3.83%, P < .0001), despite the high-fat intake. These findings reinforce the use of AECI in hyperglycemia and highlight the potential extract's effect in preventing weight gain and fat accumulation in liver of diet-induced obese mice. PMID:26854845

  8. Experimental studies of high order soliton compression effect and gain characteristics in femtosecond laser pulses Er3+-doped fiber amplifier

    刘东峰; 陈国夫; 白晋涛; 王贤华

    2000-01-01

    Seed laser pulses with average power of 146 pW and pulse duration of 480 fs were amplified to 14.5 mW. The pulse duration was compressed to 260 fs using 6 m high concentration Er3+ -doped fiber under forward pumping. The amplified signal pulse energy was 0.691 nJ (corresponding to a peak power of 2 657.7 W) and the repetition rate was 20.84 MHz. Spectrum breakup was observed simultaneously. The spectrum of pulses amplified by 3 m Er3+ -doped fiber remains a single peak under different pump power. The amplified pulse duration was compressed abnormally with the increasing pump power using the backward pumping; that is, the amplified pulses were compressed with the increasing pump power under low pump power. When the pump power reached 38 mW, the shortest amplified pulse duration was 309 fs. With further increase in pump power, the amplified pulses began broadening, accompanied by a single peak spectrum under different pump power.

  9. A flexible and high-performance bidirectional optical amplifier with all optical gain control using ASE noise path through multi-port circulators

    An Vu Tran; Chang-Joon Chae; Rodney S. Tucker

    2003-01-01

    We report a flexible all-optical gain controlled bidirectional optical amplifier. The device achieves constant gain and low noise figure over a large input power range. Moreover, the device removes Rayleigh backscattered light and amplifier noise.

  10. High d(+)-fructose diet adversely affects testicular weight gain in weaning rats─protection by moderate d(+)-glucose diet.

    Shibata, Katsumi; Fukuwatari, Tsutomu

    2013-01-01

    The use of high D(+)-fructose corn syrup has increased over the past several decades in the developed countries, while overweight and obesity rates and the related diseases have risen dramatically. However, we found that feeding a high D(+)-fructose diet (80% D(+)-fructose as part of the diet) to weaning rats for 21 days led to reduced food intake (50% less, P fructose diet. We also challenged a minimum requirement of dietary D(+)-glucose for preventing the adverse effects of D(+)-fructose, such as lower food intake and reduction of body weight and testicular weight; the minimum requirement of D(+)-glucose was ≈23% of the diet. This glucose amount may be the minimum requirement of exogenous glucose for reducing weight gain. PMID:23935370

  11. Whey-reduced weight gain is associated with a temporary growth reduction in young mice fed a high-fat diet

    Tranberg, Britt; Madsen, Andreas N.; Hansen, Axel K.;

    2015-01-01

    Whey protein consumption reportedly alleviates parameters of the metabolic syndrome. Here, we investigated the effects of whey protein isolate (whey) in young mice fed a high-fat diet. We hypothesized that whey as the sole protein source reduced early weight gain associated with retarded growth...... and decreased concentration of insulin-like growth factor-1. Moreover, we hypothesized that these changes were explained by increased nitrogen loss via elevated urea production and/or increased energy expenditure. Male 5-week-old C57BL/6 mice were fed high-fat diets with the protein source being either whey......, casein or a combination of both for 5 weeks. After 1, 3 or 5 weeks, respectively, the mice were subjected to a meal challenge with measurements of blood and urinary urea before and 1 and 3 h after eating a weighed meal of their respective diets. In a subset of mice, energy expenditure was measured...

  12. Gain ranging amplifier

    A gain ranging amplifier system is provided for use in the acquisition of data. Voltage offset compensation is utilized to correct errors in the gain ranging amplifier system caused by thermal drift and temperature dependent voltage offsets, both of which are associated with amplifiers in the gain ranging amplifier system

  13. High-capacity neutron activation analysis facility

    A high-capacity neutron activation analysis facility, the Reactor Activation Facility, was designed and built and has been in operation for about a year at one of the Savannah River Plant's production reactors. The facility determines uranium and about 19 other elements in hydrogeochemical samples collected in the National Uranium Resource Evaluation program, which is sponsored and funded by the United States Department of Energy, Grand Junction Office. The facility has a demonstrated average analysis rate of over 10,000 samples per month, and a peak rate of over 16,000 samples per month. Uranium is determined by cyclic activation and delayed neutron counting of the U-235 fission products; other elements are determined from gamma-ray spectra recorded in subsequent irradiation, decay, and counting steps. The method relies on the absolute activation technique and is highly automated for round-the-clock unattended operation

  14. Gain-of-function mutations in the Toll-like Receptor pathway: TPL2-mediated ERK1/ERK2 MAPK activation, a path to tumorigenesis in lymphoid neoplasms?

    Simon eRousseau

    2016-05-01

    Full Text Available Lymphoid neoplasms form a family of cancers affecting B-cells, T-cells and NK cells. The Toll-Like Receptor (TLR signalling adapter molecule MYD88 is the most frequently mutated gene in these neoplasms. This signalling adaptor relays signals from TLRs to downstream effector pathways such as the Nuclear Factor kappa B (NFB and Mitogen Activated Protein Kinase (MAPK pathways to regulate innate immune responses (Kawai and Akira, 2010. Gain-of-function mutations such as MYD88[L265P] activate downstream signalling pathways in absence of cognate ligands for TLRs, resulting in increased cellular proliferation and survival. This article reports an analysis of non-synonymous somatic mutations found in the TLR signaling network in lymphoid neoplasms. In accordance with previous reports, mutations map to MYD88 pro-inflammatory signaling and not TRIF-mediated Type I IFN production. Interestingly, the analysis of somatic mutations found downstream of the core TLR-signaling network uncovered a strong association with the ERK1/2 MAPK cascade. In support of this analysis, heterologous expression of MYD88[L265P] in HEK 293 cells led to ERK1/2 MAPK phosphorylation in addition to NFB activation. Moreover, this activation is dependent on the protein kinase Tumour Promoting Locus-2 (TPL-2, activated downstream of the IKK complex. Activation of ERK1/2 would then lead to activation, amongst others, of MYC and hnRNP A1, two proteins previously shown to contribute to tumour formation in lymphoid neoplasms. Taken together, this analysis suggests that TLR-mediated tumorigenesis occurs via the TPL2-mediated ERK1/2 activation. Therefore, the hypothesis proposed is that inhibition of ERK1/2 MAPK activation would prevent tumour growth downstream of MYD88[L265]. It will be interesting to test whether pharmacological inhibitors of this pathway show efficacy in primary tumour cells derived from hematologic malignancies such as Waldenstrom’s Macroglobulinemia, where the

  15. Gain-of-Function Mutations in the Toll-Like Receptor Pathway: TPL2-Mediated ERK1/ERK2 MAPK Activation, a Path to Tumorigenesis in Lymphoid Neoplasms?

    Rousseau, Simon; Martel, Guy

    2016-01-01

    Lymphoid neoplasms form a family of cancers affecting B-cells, T-cells, and NK cells. The Toll-Like Receptor (TLR) signaling adapter molecule MYD88 is the most frequently mutated gene in these neoplasms. This signaling adaptor relays signals from TLRs to downstream effector pathways such as the Nuclear Factor kappa B (NFκB) and Mitogen Activated Protein Kinase (MAPK) pathways to regulate innate immune responses. Gain-of-function mutations such as MYD88[L265P] activate downstream signaling pathways in absence of cognate ligands for TLRs, resulting in increased cellular proliferation and survival. This article reports an analysis of non-synonymous somatic mutations found in the TLR signaling network in lymphoid neoplasms. In accordance with previous reports, mutations map to MYD88 pro-inflammatory signaling and not TRIF-mediated Type I IFN production. Interestingly, the analysis of somatic mutations found downstream of the core TLR-signaling network uncovered a strong association with the ERK1/2 MAPK cascade. In support of this analysis, heterologous expression of MYD88[L265P] in HEK293 cells led to ERK1/2 MAPK phosphorylation in addition to NFκB activation. Moreover, this activation is dependent on the protein kinase Tumor Promoting Locus 2 (TPL2), activated downstream of the IKK complex. Activation of ERK1/2 would then lead to activation, amongst others, of MYC and hnRNPA1, two proteins previously shown to contribute to tumor formation in lymphoid neoplasms. Taken together, this analysis suggests that TLR-mediated ERK1/2 activation via TPL2 may be a novel path to tumorigenesis. Therefore, the hypothesis proposed is that inhibition of ERK1/2 MAPK activation would prevent tumor growth downstream of MYD88[L265]. It will be interesting to test whether pharmacological inhibitors of this pathway show efficacy in primary tumor cells derived from hematologic malignancies such as Waldenstrom's Macroglobulinemia, where the majority of the cells carry the MYD88[L265P

  16. Lower weight gain and hepatic lipid content in hamsters fed high fat diets supplemented with white rice protein, brown rice protein, soy protein, and their hydrolysates.

    Zhang, Huijuan; Bartley, Glenn E; Mitchell, Cheryl R; Zhang, Hui; Yokoyama, Wallace

    2011-10-26

    The physiological effects of the hydrolysates of white rice protein (WRP), brown rice protein (BRP), and soy protein (SP) hydrolyzed by the food grade enzyme, alcalase2.4 L, were compared to the original protein source. Male Syrian Golden hamsters were fed high-fat diets containing either 20% casein (control) or 20% extracted proteins or their hydrolysates as the protein source for 3 weeks. The brown rice protein hydrolysate (BRPH) diet group reduced weight gain 76% compared with the control. Animals fed the BRPH supplemented diet also had lower final body weight, liver weight, very low density lipoprotein cholesterol (VLDL-C), and liver cholesterol, and higher fecal fat and bile acid excretion than the control. Expression levels of hepatic genes for lipid oxidation, PPARα, ACOX1, and CPT1, were highest for hamsters fed the BRPH supplemented diet. Expression of CYP7A1, the gene regulating bile acid synthesis, was higher in all test groups. Expression of CYP51, a gene coding for an enzyme involved in cholesterol synthesis, was highest in the BRPH diet group. The results suggest that BRPH includes unique peptides that reduce weight gain and hepatic cholesterol synthesis. PMID:21913675

  17. Enclosure for handling high activity materials

    One of the most important problems that are met at the laboratories producing and handling radioisotopes is that of designing, building and operating enclosures suitable for the safe handling of active substances. With this purpose in mind, an enclosure has been designed and built for handling moderately high activities under a shielding made of 150 mm thick lead. In this report a description is given of those aspects that may be of interest to people working in this field. (Author)

  18. Enclosure for handling high activity materials

    Jimeno de Osso, F.

    1977-07-01

    One of the most important problems that are met at the laboratories producing and handling radioisotopes is that of designing, building and operating enclosures suitable for the safe handling of active substances. With this purpose in mind, an enclosure has been designed and built for handling moderately high activities under a shielding made of 150 mm thick lead. In this report a description is given of those aspects that may be of interest to people working in this field. (Author)

  19. Plasma Switch for High-Power Active Pulse Compressor

    Hirshfield, Jay L. [Omega-P, Inc.

    2013-11-04

    Results are presented from experiments carried out at the Naval Research Laboratory X-band magnicon facility on a two-channel X-band active RF pulse compressor that employed plasma switches. Experimental evidence is shown to validate the basic goals of the project, which include: simultaneous firing of plasma switches in both channels of the RF circuit, operation of quasi-optical 3-dB hybrid directional coupler coherent superposition of RF compressed pulses from both channels, and operation of the X-band magnicon directly in the RF pulse compressor. For incident 1.2 ?s pulses in the range 0.63 ? 1.35 MW, compressed pulses of peak powers 5.7 ? 11.3 MW were obtained, corresponding to peak power gain ratios of 8.3 ? 9.3. Insufficient bakeout and conditioning of the high-power RF circuit prevented experiments from being conducted at higher RF input power levels.

  20. Size exclusion chromatography to gain insight into the complex formation of carrot pectin methylesterase and its inhibitor from kiwi fruit as influenced by thermal and high-pressure processing.

    Jolie, Ruben P; Duvetter, Thomas; Verlinde, Philippe H C J; Van Buggenhout, Sandy; Van Loey, Ann M; Hendrickx, Marc E

    2009-12-01

    A size exclusion chromatography (HPSEC) method was implemented to study complex formation between carrot pectin methylesterase (PME) and its inhibitor (PMEI) from kiwi fruit in the context of traditional thermal and novel high-pressure processing. Evidence was gained that both thermal and high-pressure treatments of PME give rise to two distinct enzyme subpopulations: a catalytically active population, eluting from the size exclusion column, and an inactive population, aggregated and excluded from the column. When mixing a partly denatured PME sample with a fixed amount of PMEI, a PME-PMEI complex peak was observed on HPSEC, of which the peak area was highly correlated with the residual enzyme activity of the corresponding PME sample. This observation indicates complex formation to be restricted to the active PME fraction. When an equimolar mixture of PME and PMEI was subjected to either a thermal or a high-pressure treatment, marked differences were observed. At elevated temperature, enzyme and inhibitor remained united and aggregated as a whole, thus gradually disappearing from the elution profile. Conversely, elevated pressure caused the dissociation of the PME-PMEI complexes, followed by a separate action of pressure on enzyme and inhibitor. Remarkably, PMEI appeared to be pressure-resistant when compressed at acidic pH (ca. 4). PMID:19908835

  1. Tunable Plasmonic Nanoparticles with Catalytically Active High-Index Facets

    Jing, Hao; Large, Nicolas; Zhang, Qinfeng; Nordlander, Peter; Wang, Hui

    2015-03-01

    Noble metal nanoparticles have been of tremendous interest due to their intriguing size- and shape-dependent plasmonic and catalytic properties. Combining tunable plasmon resonances with superior catalytic activities on the same metallic nanoparticle, however, has long been challenging because nanoplasmonics and nanocatalysis typically require nanoparticles in two drastically different size regimes. Here, we demonstrate that creation of high-index facets on subwavelength metallic nanoparticles provides a unique approach to the integration of desired plasmonic and catalytic properties on the same nanoparticle. Through site-selective surface etching of metallic nanocuboids whose surfaces are dominated by low-index facets, we have controllably fabricated nanorice and nanodumbbell shaped particles, which exhibit drastically enhanced catalytic activities arising from the catalytically active high-index facets abundant on the particle surfaces. The nanorice and nanodumbbell particles also possess appealing tunable plasmonic properties that allow us to gain quantitative insights into nanoparticle-catalyzed reactions with unprecedented sensitivity and detail through time-resolved plasmon-enhanced spectroscopic measurements. Past affiliation: Rice University.

  2. Relative contributions of energy expenditure on physical activity, body composition and weight gain to the evolution of impaired glucose tolerance to Frank diabetes

    The effect of obesity on glucose intolerance is a mixture of impact of body composition on glucose-insulin relationships as well as the modulation of this metabolism by physical activity. In this project, we seek to measure the energy expenditure on activity, the rate of weight gain and changes in body composition in a free-living population, and to relate these variables to changes in glucose tolerance and insulin sensitivity. We have enrolled a cohort of 280 adults in Idikan, a poor urban community in lbadan, Nigeria, selected by simple random sampling from a population database. In this communication, we report characteristics of the study cohort, findings on evaluation of a physical activity questionnaire and changes in body size, body composition and measures of insulin resistance over a one-year period. Mean age of the men is 49.7 (SD 12.7) years and of the women 44.7 (SD 10.7) years. Mean fasting blood glucose was 4.57 (SD 4.75) mmol/L among men and 3.54 (SD 1.02) mmol/L among women. The modified HIP physical activity (PA) questionnaire was evaluated in a subset of participants for whom scale reliability coefficients of 0.57 and 0.33 were obtained for the occupational and leisure scales of HIP respectively. Two-week test-retest intraclass correlation coefficient was 0.53. On validation against doubly-labelled water measurements, the HIP occupational score showed a positive correlation (r=0.37, p=0.01) with activity energy expenditure per kg body weight (AEE per kg) and a similar correlation of 0. 37 with physical activity level (PAL). Thus, the HIP occupational scale showed adequate consistency, good test-retest reliability and good correlations with measures of physical activity by doubly-labelled water. Over a one-year follow-up period, the participants showed increases in weight, BMI, waist circumferences, fat mass, fasting insulin and insulin-to-glucose ratio. However, HOMA-IR did not significantly change. Overweight increased from 21.3% to 23.9% while

  3. A new Methodology for achieving MMIC Bandpass Active Filters at High Frequencies

    Darcel, L.; Duême, P.; Funck, R.; Alquié, G.

    2004-01-01

    This paper presents a new methodology based on actively coupled resonators, for achieving microwave active filters. In this method, which lends itself to narrowband and wideband filtering applications, we associate core cells with different resonance frequencies, adjusted separately, to synthesise a Butterworth, Chebyshev or other all-pole approximation. Two 1-pole bandpass filters centred at 9GHz, with 3dB bandwidth of 500 MHz, high gain of 17 dB and 21 dB, including ...

  4. High active waste (HAW) data report

    This report is a supplement to the first data report on High Active Waste (HAW; ECN-PB--89-6). It contains the graphs of a number of calculated values for the period November 1988 through April 1989. (A.S.). 4 figs

  5. Change, Gain and Loss

    Fu Mengzi

    2006-01-01

    @@ Five years have passed since the September 11 terrorist attacks occurred. America's counter-terrorism campaign is still on the way.Besides the momentary monumental significance of the fifth anniversary, five years is still too short in regard to the long-term counter-terrorism campaign. Yet, America's president's tenure is eight years at best; most of Bush's presidency time has passed. Five years ago, the U. S. encountered the most serious terrorist attack; the whole nation formed a consensus that counter-terrorism is its utmost priority. President Bush once enjoyed a support rate as high as 90% for over 16 months. But five years later, the trend changes. People can not help but ask: what are the gains and losses of the Republican Party in dealing with national security affairs?

  6. IAEA high temperature gas cooled reactor activities

    IAEA activities on high temperature gas cooled reactors are conducted with the review and support of Member States, primarily through the International Working Group on Gas Cooled Reactors (IWGGCR). This paper summarises the results of the IAEA gas cooled reactor project activities in recent years along with ongoing current activities through a review of Co-ordinated Research Projects (CRPs), meetings and other international efforts. A series of three recently completed CRPs have addressed the key areas of reactor physics for LEU fuel, retention of fission products, and removal of post shutdown decay heat through passive heat transport mechanisms. These activities along with other completed and ongoing supporting CRPs and meetings are summarised with reference to detailed documentation of the results. (author)

  7. Activity-based Costing (ABC and Activity-based Management(ABMImplementation – Is This the Solution for Organizations to Gain Profitability?

    Ildikó Réka CARDOS

    2011-06-01

    Full Text Available Adherents of ABC/ABM systems claimed traditional management accounting systems generated misleading costs in a contemporary, tumultuous, often changing business environment and implementing ABC/ABM would remedy this. That is why activity-based costing (ABC and activity-based management (ABM represents the symbol of improved competitiveness and efficiency in every organization.The purpose of this article – after analyzing the existing literature in the field – is to emphasize that new cost systems such as ABC and ABM could be a strong couple that assures competitiveness and efficiency for each company. Another objective is to present that, besides its disadvantages, firms implement the ABC/ABM system because it permits better tracing of costs to objects, superior allocation of overheads to cost objects, financial and non-financial analysis and measures useful to managers and management accountants in the decision-making process.

  8. 一种新型的高增益低剖面天线%A Novel Low-Profile High-Gain Antenna

    杨奋华; 汤炜

    2013-01-01

    A novel antenna with low profile and high gain is proposed, thus to solve the low-gain and narrow-band problems of conventional antenna. The antenna adopts an AMC (artificial magnetic conductor) ground plane as its reflecting surface, and the traditional printed bow-tie antenna is oriented horizontally over the AMC surface consisted of 5×7 square plum-shaped patches unit. The optimized antenna, with a center frequency of 3.85GHz and a relative bandwidth of 11.63%, covers the LTE (Long Term Evolution) range from 2.5GHz to 2.69GHz. Moreover, the composite antenna has an overall height of 9.5mm, one-twelfth of the wavelength at the center frequency. In addition, the peak gain of the composite antenna is close to 9.7dBi, and this confirms the feasibility of this new antenna.%  为了解决传统天线低增益、窄频带和大尺寸的问题,提出了一种新型的高增益低剖面天线.该天线采用人工磁导体(AMC)作为反射面,具体结构是将双面印刷蝶形天线作为辐射天线悬置在5×7梅花单元反射面上.经优化,该天线的中心频率为2.58 GHz,相对带宽为11.63%,覆盖了LTE(长期演进)中的2500~2690 MHz频段,且天线的总体高度仅为9.5 mm,相当于自由空间波长的1/12.此外,该天线的峰值增益达到9.7 dBi,证实了新型天线的可行性.

  9. Effect of Myostatin Depletion on Weight Gain, Hyperglycemia, and Hepatic Steatosis during Five Months of High-Fat Feeding in Mice

    Burgess, Kerri; Xu, Tianshun; Brown, Roger; Han, Bajin; Welle, Stephen

    2011-01-01

    The marked hypermuscularity in mice with constitutive myostatin deficiency reduces fat accumulation and hyperglycemia induced by high-fat feeding, but it is unclear whether the smaller increase in muscle mass caused by postdevelopmental loss of myostatin activity has beneficial metabolic effects during high-fat feeding. We therefore examined how postdevelopmental myostatin knockout influenced effects of high-fat feeding. Male mice with ubiquitous expression of tamoxifen-inducible Cre recombin...

  10. VECSEL gain characterization

    Mangold, Mario; Wittwer, Valentin J; Sieber, Oliver D.; Hoffmann, Martin; Krestnikov, Igor L; Livshits, Daniil A.; Golling, Matthias; Südmeyer, Thomas; Keller, Ursula

    2012-01-01

    We present the first full gain characterization of two vertical external cavity surface emitting laser (VECSEL) gain chips with similar designs operating in the 960-nm wavelength regime. We optically pump the structures with continuous-wave (cw) 808-nm radiation and measure the nonlinear reflectivity for 130-fs and 1.4-ps probe pulses as function of probe pulse fluence, pump power, and heat sink temperature. With this technique we are able to measure the saturation behavior for VECSEL gain ch...

  11. Autoregressive-model-based fluorescence-lifetime measurements by phase-modulation fluorometry using a pulsed-excitation light source and a high-gain photomultiplier tube.

    Iwata, Tetsuo; Ito, Ritsuki; Mizutani, Yasuhiro; Araki, Tsutomu

    2009-11-01

    We propose a novel method for measuring fluorescence lifetimes by use of a pulsed-excitation light source and an ordinary or a high-gain photomultiplier tube (PMT) with a high-load resistor. In order to obtain the values of fluorescence lifetimes, we adopt a normal data-processing procedure used in phase-modulation fluorometry. We apply an autoregressive (AR)-model-based data-analysis technique to fluorescence- and reference-response time-series data obtained from the PMT in order to derive plural values of phase differences at a repetition frequency of the pulsed-excitation light source and its harmonic ones. The connection of the high-load resistor enhances sensitivity in signal detection in a certain condition. Introduction of the AR-model-based data-analysis technique improves precision in estimating the values of fluorescence lifetimes. Depending on the value of the load resistor and that of the repetition frequency, plural values of fluorescence lifetimes are obtained at one time by utilizing the phase information of harmonic frequencies. Because the proposed measurement system is simple to construct, it might be effective when we need to know approximate values of fluorescence lifetimes readily, such as in the field of biochemistry for a screening purpose. PMID:19891834

  12. Production of high specific activity silicon-32

    Phillips, D.R. [Los Alamos National Lab., NM (United States); Brzezinski, M.A. [Univ. of California, Santa Barbara, CA (United States). Marine Biotechnology Center

    1998-12-31

    This is the final report of a three-year, Laboratory Directed Research and Development Project (LDRD) at Los Alamos National Laboratory (LANL). There were two primary objectives for the work performed under this project. The first was to take advantage of capabilities and facilities at Los Alamos to produce the radionuclide {sup 32}Si in unusually high specific activity. The second was to combine the radioanalytical expertise at Los Alamos with the expertise at the University of California to develop methods for the application of {sup 32}Si in biological oceanographic research related to global climate modeling. The first objective was met by developing targetry for proton spallation production of {sup 32}Si in KCl targets and chemistry for its recovery in very high specific activity. The second objective was met by developing a validated field-useable, radioanalytical technique, based upon gas-flow proportional counting, to measure the dynamics of silicon uptake by naturally occurring diatoms.

  13. Production of high specific activity silicon-32

    This is the final report of a three-year, Laboratory Directed Research and Development Project (LDRD) at Los Alamos National Laboratory (LANL). There were two primary objectives for the work performed under this project. The first was to take advantage of capabilities and facilities at Los Alamos to produce the radionuclide 32Si in unusually high specific activity. The second was to combine the radioanalytical expertise at Los Alamos with the expertise at the University of California to develop methods for the application of 32Si in biological oceanographic research related to global climate modeling. The first objective was met by developing targetry for proton spallation production of 32Si in KCl targets and chemistry for its recovery in very high specific activity. The second objective was met by developing a validated field-useable, radioanalytical technique, based upon gas-flow proportional counting, to measure the dynamics of silicon uptake by naturally occurring diatoms

  14. Geotech Smart24 data acquisition system input terminated noise seismic response adjusted test : StreckeisenSTS2-low and high gain, Guralp CMG3T and Geotech GS13 seismometers.

    Rembold, Randy Kai; Hart, Darren M.; Harris, James Mark

    2008-08-01

    Sandia National Laboratories has tested, evaluated and reported on the Geotech Smart24 data acquisition system with active Fortezza crypto card data signing and authentication in SAND2008-. One test, Input Terminated Noise, allows us to characterize the self-noise of the Smart24 system. By computing the power spectral density (PSD) of the input terminated noise time series data set and correcting for the instrument response of different seismometers, the resulting spectrum can be compared to the USGS new low noise model (NLNM) of Peterson (1996), and determine the ability of the matched system of seismometer and Smart24 to be quiet enough for any general deployment location. Four seismometer models were evaluated: the Streckeisen STS2-Low and High Gain, Guralp CMG3T and Geotech GS13 models. Each has a unique pass-band as defined by the frequency band of the instrument corrected noise spectrum that falls below the new low-noise model.

  15. Moderate resistance training volume produces more favorable strength gains than high or low volumes during a short-term training cycle.

    González-Badillo, Juan J; Gorostiaga, Esteban M; Arellano, Raúl; Izquierdo, Mikel

    2005-08-01

    The purpose of this study was to examine the effects of 3 resistance training volumes on maximal strength in the snatch (Sn), clean & jerk (C&J), and squat (Sq) exercises during a 10-week training period. Fifty-one experienced (>3 years), trained junior lifters were randomly assigned to one of 3 groups: a low-volume group (LVG, n = 16), a moderate-volume group (MVG, n = 17), and a high-volume group (HVG, n = 18). All subjects trained 4-5 days a week with a periodized routine using the same exercises and relative intensities but a different total number of sets and repetitions at each relative load: LVG (1,923 repetitions), MVG (2,481 repetitions), and HVG (3,030 repetitions). The training was periodized from moderate intensity (60- 80% of 1 repetition maximum [1RM]) and high number of repetitions per set (2-6) to high intensity (90-100% of 1RM) and low number of repetitions per set (1-3). During the training period, the MVG showed a significant increase for the Sn, C&J, and Sq exercises (6.1, 3.7, and 4.2%, respectively, p < 0.01), whereas in the LVG and HVG, the increase took place only with the C&J exercise (3.7 and 3%, respectively, p < 0.05) and the Sq exercise (4.6%, p < 0.05, and 4.8%, p < 0.01, respectively). The increase in the Sn exercise for the MVG was significantly higher than in the LVG (p = 0.015). Calculation of effect sizes showed higher strength gains in the MVG than in the HVG or LVG. There were no significant differences between the LVG and HVG training volume-induced strength gains. The present results indicate that junior experienced lifters can optimize performance by exercising with only 85% or less of the maximal volume that they can tolerate. These observations may have important practical relevance for the optimal design of strength training programs for resistance-trained athletes, since we have shown that performing at a moderate volume is more effective and efficient than performing at a higher volume. PMID:16095427

  16. Characterising highly active nuclear waste simulants

    Paul, N; Biggs, S.; Edmondson, M; Hunter, TN; Hammond, RB

    2013-01-01

    Reprocessing of spent nuclear fuel produces a highly active liquor (HAL) waste stream, which is typically stored over extended periods of many years in waste tanks equipped with extensive heat exchange capability. Over time, particulates are known to precipitate from the HAL within these tanks. Particle simulants provide a route for understanding the physical behaviour of these HAL solids under different agitation and transfer conditions. Particle and dispersion characterisation techniques ar...

  17. Relational Information Gain

    Lippi, Marco; Jaeger, Manfred; Frasconi, Paolo;

    2011-01-01

    We introduce relational information gain, a refinement scoring function measuring the informativeness of newly introduced variables. The gain can be interpreted as a conditional entropy in a well-defined sense and can be efficiently approximately computed. In conjunction with simple greedy general...

  18. Health gain versus equity.

    Scott-Samuel, A

    1992-05-01

    A new organisation, the Association for Public Health, has just been formed 'to help deliver real health gain for the population'. Alex Scott-Samuel suggests that the concept of 'health gain' is counter to health equality and needs wider debate. PMID:1624317

  19. Should I Gain Weight?

    ... Can I Help a Friend Who Cuts? Should I Gain Weight? KidsHealth > For Teens > Should I Gain Weight? Print A A A Text Size ... Healthy Habits Matter en español ¿Debería ganar peso? "I want to play hockey, like I did in ...

  20. High energy activation data library (HEAD-2009)

    A proton activation data library for 682 nuclides from 1H to 210Po in the energy range from 150 MeV up to 1 GeV was developed. To calculate proton activation data, the MCNPX 2.6.0 and CASCADE/INPE codes were chosen. Different intranuclear cascade, preequilibrium, and equilibrium nuclear reaction models and their combinations were used. The optimum calculation models have been chosen on the basis of statistical correlations for calculated and experimental proton data taken from the EXFOR library of experimental nuclear data. All the data are written in ENDF-6 format. The library is called HEPAD-2008 (High-Energy Proton Activation Data). A revision of IEAF-2005 neutron activation data library has been performed. A set of nuclides for which the cross-section data can be (and were) updated using more modern and improved models is specified, and the corresponding calculations have been made in the present work. The new version of the library is called IEAF-2009. The HEPAD-2008 and IEAF-2009 are merged to the final HEAD-2009 library.

  1. Rice koji reduced body weight gain, fat accumulation, and blood glucose level in high-fat diet-induced obese mice

    Yumiko Yoshizaki

    2014-08-01

    Full Text Available Rice koji is considered a readily accessible functional food that may have health-promoting effects. We investigated whether white, yellow, and red koji have the anti-obesity effect in C57BL/6J mice fed a high-fat diet (HFD, which is a model for obesity. Mice were fed HFD containing 10% (w/w of rice koji powder or steamed rice for 4 weeks. Weight gain, epididymal white adipose tissue, and total adipose tissue weight were significantly lower in all rice koji groups than in the HFD-rice group after 4 weeks. Feed efficiency was significantly reduced in the yellow koji group. Blood glucose levels were significantly lower in the white and red koji groups with HOMA-R and leptin levels being reduced in the white koji group. White and red koji increased glucose uptake and GLUT4 protein expression in L6 myotube cells. These results showed that all rice koji have the anti-obesity or anti-diabetes effects although the mechanisms may differ depending on the type of rice koji consumed.

  2. High Internal Gain Axial SiOx-In2-xO3-y/Au Heterostructure Nanocolumnar Array Based Schottky Detector for Broad Band Recognition.

    Singh, Naorem Khelchand; Mondal, Aniruddha

    2015-08-01

    Glancing angle deposition (GLAD) was employed to fabricate the SiOx-In2-xO3-y axial heterostructure nanocolumn. The fabricated heterostructure nanocolumn was annealed at 550 °C for 1 hour at open air condition. The XRD analysis revealed the polycrystalline nature of the annealed SiOx-In2-xO3-y nanocolumn. The emission at 378 nm (~3.3 eV, FWHM 39.101 nm) from Photoluminescence (PL), corresponds to main band gap of In2O3. The In2-xO3-y-SiOx nanocolumn based Schottky detector processed maximum photoresponsivity of 199 A/W at 375 nm, as well as UV-Vis broad band detection. The high internal gain of ~659 at UV region (375 nm) was calculated for the device. The detector exhibited increase in photoresponsivity with decrease in room temperature upto 160 K, which further reduced at low temperature. A very sharp rise time (~1.82 s) and decay time (~1.78 s) was recorded at the applied potential of -2 V and -3 V. PMID:26369205

  3. Associations of neonatal high birth weight with maternal pre-pregnancy body mass index and gestational weight gain: a case–control study in women from Chongqing, China

    Peng, Rong; Han, Lingli; Zhou, Xiaoli; Xiong, Zhengai; Zhang, Yuan; Li, Junnan; Yao, Ruoxue; Li, Tingyu; Zhao, Yong

    2016-01-01

    Objectives To examine the associations of maternal pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) with neonatal high birth weight (HBW) in a sample of Chinese women living in southwest China. Methods A hospital-based case–control study was conducted in Chongqing, China. A total of 221 mothers who delivered HBW babies (>4.0 kg) were recruited as cases and 221 age-matched (2-year interval) mothers with normal birth weight babies (2.5–4.0 kg) were identified as controls. ORs were estimated using conditional logistic regression analysis. For the analysis, pre-pregnancy BMI was categorised as underweight/normal weight/overweight and obesity and GWG was categorised as inadequate/appropriate/excessive. Results Among the cases, mean pre-pregnancy BMI was 21.8±2.8 kg/m2, mean GWG was 19.7±5.1 kg and mean neonatal birth weight was 4.2±0.2 kg. In the controls, the corresponding values were 21.1±3.1 kg/m2, 16.4±5.0 kg and 3.3±0.4 kg, respectively. More cases than controls gained excessive weight during pregnancy (80.1% vs 48.4%, p0.05). GWG was positively related to HBW after adjustment for gravidity, gestational age, newborns' gender and family income (OR=1.18, 95% CI 1.12 to 1.25; p<0.001). The adjusted OR of delivering HBW babies was 5.39 (95% CI 2.94 to 9.89; p<0.001) for excessive GWG versus appropriate GWG. This OR was strengthened among pre-pregnancy normal weight women (OR=10.27, 95% CI 3.20 to 32.95; p<0.001). Conclusions Overall, the findings suggest a significantly positive association between GWG and HBW. However, pre-pregnancy BMI shows no independent relationship with HBW. PMID:27531723

  4. Differences in the Gained Results of the Male Students’ Achievements in First Year in Sport and Sport’s Activities Schooling

    Mitrevski, Viktor; Georgiev, Georgi; Klincarov, Ilija; Popeska, Biljana

    2009-01-01

    The research conducted above 353 male and female high school students from few cities in Macedonia, needs three sub-examples of those examinee students. Those subexamples are all males and their number is 81 from first grade who regularly were attending the sport and sport’s activities schooling in different working conditions. With multi-variance and univariance analysis(MANOVA, ANOVA) there are differences among the achievements of the students, expressed by numerical mark grades in f...

  5. Proteasome inhibitors and IMiDs can overcome some high-risk cytogenetics in multiple myeloma but not gain 1q21

    Nahi, Hareth; Våtsveen, Thea Kristin; Lund, Johan;

    2015-01-01

    ), that is, del(13q), del(17p), t(4,14), and/or (14;16), and 123 patients with no aberrations (NA). The groups were compared in terms of overall survival (OS), time to progression (TTP), and response. The 3-yr OS for patients with gain 1q21 was 60% compared to patients with OA 74% and NO 82% (gain 1q21 vs...

  6. On capital gain taxation

    Anton Miglo

    2008-01-01

    This note provides an explanation for why tax rates on capital gains are usually lower than ordinary income tax rates based on manager's agency problem related to "empire-building" or the underinvestment problem.

  7. The effect of gain saturation in a gain compensated perfect lens

    Andresen, Marte P Hatlo; Haakestad, Magnus W; Krogstad, Harald E; Skaar, Johannes

    2010-01-01

    The transmission of evanescent waves in a gain-compensated perfect lens is discussed. In particular, the impact of gain saturation is included in the analysis, and a method for calculating the fields of such nonlinear systems is developed. Gain compensation clearly improves the resolution; however, a number of nonideal effects arise as a result of gain saturation. The resolution associated with the lens is strongly dependent on the saturation constant of the active medium.

  8. Tunability of optical gain (SWIR region) in type-II In0.70Ga0.30As/GaAs0.40Sb0.60 nano-heterostructure under high pressure

    Nirmal, H. K.; Yadav, Nisha; Dalela, S.; Rathi, Amit; Siddiqui, M. J.; Alvi, P. A.

    2016-06-01

    The interest in applying an external pressure on a nano-heterostructure is to attempt to extract more information about the electronic structure through distortion of the electronic structure. This paper reports the tunability of the optical gain under the high pressure effect in M-shaped type-II In0.70Ga0.30As/GaAs0.40Sb0.60 symmetric lasing nano-heterostructure designed for SWIR generation. In order to simulate the optical gain, the heterostructure has been modeled with the help of six band k.p method. The 6×6 diagonalized k.p Hamiltonian has been solved to evaluate the valence sub-bands (i.e. light and heavy hole energies); and then optical matrix elements and optical gain within TE (Transverse Electric) mode has been calculated. For the injected carrier density of 5×1012/cm2, the optimized optical gain within TE mode is as high as ~9000/cm at the wavelength of ~1.95 μm, thus providing a very important alternative material system for the generation of SWIR wavelength region. The application of very high pressure (2, 5 and 8 GPa) on the structure along [110] direction shows that the gain as well as lasing wavelength both approach to higher values. Thus, the structure can be tuned externally by the application of high pressure within the SWIR region.

  9. Concrete with Highly Active Rice Husk Ash

    FENG Qing-ge; LIN Qing-yu; YU Qi-jun; ZHAO San-ying; YANG Lu-feng; Shuichi Sugita

    2004-01-01

    The overall aim was to investigate the effect of highly active rice husk ash (RHA) produced by an industrial furnace on some properties of concrete. The strength, pore volume and pore distribution of concrete and the Ca(OH)2 content in concrete were investigated by JIS A 1108 (Method of test for compressive strength of concrete), a mercury instrument porosimeter, and the thermogravimetric analysis, respectively. The results show that,with RHA replacement of cement,the compressive strength of concrete is increased evidently;the average pore radius of concrete is greatly decreased, especially the portion of the pores greater than 20nm in radius is decreased while the amount of smaller pores is increased, and the more the RHA replacement, the less the amount of Ca(OH)2 in concrete. The latter two results are the main reasons for the strength enhancement of concrete.

  10. High gain L-band erbium-doped fiber amplifier with two-stage double-pass configuration

    S W Harun; N Tamchek; P Poopalan; H Ahmad

    2003-07-01

    An experiment on gain enhancement in the long wavelength band erbium-doped fiber amplifier (L-band EDFA) is demonstrated using dual forward pumping scheme in double-pass system. Compared to a single-stage single-pass scheme, the small signal gain for 1580 nm signal can be improved by 13.5 dB. However, a noise figure penalty of 2.9 dB was obtained due to the backward C-band ASE from second stage and the already amplified signal from the first pass that extracting energy from the forward C-band ASE. The maximum gain improvement of 13.7 dB was obtained at a signal wavelength of 1588 nm while signal and total pump powers were fixed at -30 dBm and 92 mW, respectively.

  11. Gaining Mindshare and Timeshare : Marketing Public Libraries

    Paul, Johnson; Kua, Lena; Narayanan, N. Varaprasad

    2005-01-01

    This presentation is an examination of how the National Library Board had successfully gained market share by redefining its market space and remaking the image of libraries and librarians. Libraries were repositioned to gain mindshare and timeshare among Singaporeans, competing against the cinema, TV, video games and other leisure activities, becoming the Third Place after home and work for many.

  12. Receiver Gain Modulation Circuit

    Jones, Hollis; Racette, Paul; Walker, David; Gu, Dazhen

    2011-01-01

    A receiver gain modulation circuit (RGMC) was developed that modulates the power gain of the output of a radiometer receiver with a test signal. As the radiometer receiver switches between calibration noise references, the test signal is mixed with the calibrated noise and thus produces an ensemble set of measurements from which ensemble statistical analysis can be used to extract statistical information about the test signal. The RGMC is an enabling technology of the ensemble detector. As a key component for achieving ensemble detection and analysis, the RGMC has broad aeronautical and space applications. The RGMC can be used to test and develop new calibration algorithms, for example, to detect gain anomalies, and/or correct for slow drifts that affect climate-quality measurements over an accelerated time scale. A generalized approach to analyzing radiometer system designs yields a mathematical treatment of noise reference measurements in calibration algorithms. By treating the measurements from the different noise references as ensemble samples of the receiver state, i.e. receiver gain, a quantitative description of the non-stationary properties of the underlying receiver fluctuations can be derived. Excellent agreement has been obtained between model calculations and radiometric measurements. The mathematical formulation is equivalent to modulating the gain of a stable receiver with an externally generated signal and is the basis for ensemble detection and analysis (EDA). The concept of generating ensemble data sets using an ensemble detector is similar to the ensemble data sets generated as part of ensemble empirical mode decomposition (EEMD) with exception of a key distinguishing factor. EEMD adds noise to the signal under study whereas EDA mixes the signal with calibrated noise. It is mixing with calibrated noise that permits the measurement of temporal-functional variability of uncertainty in the underlying process. The RGMC permits the evaluation of EDA by

  13. Active interrogation of highly enriched uranium

    Fairrow, Nannette Lea

    Safeguarding special nuclear material (SNM) in the Department of Energy Complex is vital to the national security of the United States. Active and passive nondestructive assays are used to confirm the presence of SNM in various configurations ranging from waste to nuclear weapons. Confirmation measurements for nuclear weapons are more challenging because the design complicates the detection of a distinct signal for highly enriched uranium. The emphasis of this dissertation was to investigate a new nondestructive assay technique that provides an independent and distinct signal to confirm the presence of highly enriched uranium (HEU). Once completed and tested this assay method could be applied to confirmation measurements of nuclear weapons. The new system uses a 14-MeV neutron source for interrogation and records the arrival time of neutrons between the pulses with a high efficiency detection system. The data is then analyzed by the Feynman reduced variance method. The analysis determined the amount of correlation in the data and provided a unique signature of correlated fission neutrons. Measurements of HEU spheres were conducted at Los Alamos with the new system. Then, Monte Carlo calculations were performed to verify hypothesis made about the behavior of the neutrons in the experiment. Comparisons of calculated counting rates by the Monte Carlo N-Particle Transport Code (MCNP) were made with the experimental data to confirm that the measured response reflected the desired behavior of neutron interactions in the highly enriched uranium. In addition, MCNP calculations of the delayed neutron build-up were compared with the measured data. Based on the results obtained from this dissertation, this measurement method has the potential to be expanded to include mass determinations of highly enriched uranium. Although many safeguards techniques exist for measuring special nuclear material, the number of assays that can be used to confirm HEU in shielded systems is

  14. A 3.8 GHz programmable gain amplifier with a 0.1 dB gain step

    A broadband programmable gain amplifier (PGA) with a small gain step and low gain error has been designed in 0.13 μm CMOS technology. The PGA was implemented with open-loop architecture to provide wide bandwidth. A two-stage gain control method, which consists of a resistor ladder attenuator and an active fine gain control stage, provides the small gain step. A look-up table based gain control method is introduced in the fine gain control stage to lower the gain error. The proposed PGA shows a decibel-linear variable gain from −4 to 20 dB with a gain step of 0.1 dB and a gain error less than ±0.05 dB. The 3-dB bandwidth and maximum IIP3 are 3.8 GHz and 17 dBm, respectively. (semiconductor integrated circuits)

  15. High performance composites with active stiffness control.

    Tridech, Charnwit; Maples, Henry A; Robinson, Paul; Bismarck, Alexander

    2013-09-25

    High performance carbon fiber reinforced composites with controllable stiffness could revolutionize the use of composite materials in structural applications. Here we describe a structural material, which has a stiffness that can be actively controlled on demand. Such a material could have applications in morphing wings or deployable structures. A carbon fiber reinforced-epoxy composite is described that can undergo an 88% reduction in flexural stiffness at elevated temperatures and fully recover when cooled, with no discernible damage or loss in properties. Once the stiffness has been reduced, the required deformations can be achieved at much lower actuation forces. For this proof-of-concept study a thin polyacrylamide (PAAm) layer was electrocoated onto carbon fibers that were then embedded into an epoxy matrix via resin infusion. Heating the PAAm coating above its glass transition temperature caused it to soften and allowed the fibers to slide within the matrix. To produce the stiffness change the carbon fibers were used as resistance heating elements by passing a current through them. When the PAAm coating had softened, the ability of the interphase to transfer load to the fibers was significantly reduced, greatly lowering the flexural stiffness of the composite. By changing the moisture content in PAAm fiber coating, the temperature at which the PAAm softens and the composites undergo a reduction in stiffness can be tuned. PMID:23978266

  16. Photosynthetically active sunlight at high southern latitudes.

    Frederick, John E; Liao, Yixiang

    2005-01-01

    A network of scanning spectroradiometers has acquired a multiyear database of visible solar irradiance, covering wavelengths from 400 to 600 nm, at four sites in the high-latitude Southern Hemisphere, from 55 degrees S to 90 degrees S. Monthly irradiations computed from the hourly measurements reveal the character of the seasonal cycle and illustrate the role of cloudiness as functions of latitude. Near summer solstice, the combined influences of solar elevation and the duration of daylight would produce a monthly irradiation with little latitude dependence under clear skies. However, the attenuation associated with local cloudiness varies geographically, with the greatest effect at the most northern locations, Ushuaia, Argentina and Palmer Station on the Antarctic Peninsula. Near summer solstice, the South Pole experiences the largest monthly irradiation of the sites studied, where relatively clear skies contribute to this result. Scaling factors derived from radiative-transfer calculations combined with the measured 400-600 nm irradiances allow estimating irradiances integrated over the wavelength band 400-700 nm. This produces a climatology of photosynthetically active radiation for each month of the year at each site. PMID:15689179

  17. High-Throughput Analysis of Enzyme Activities

    Guoxin Lu

    2007-12-01

    High-throughput screening (HTS) techniques have been applied to many research fields nowadays. Robot microarray printing technique and automation microtiter handling technique allows HTS performing in both heterogeneous and homogeneous formats, with minimal sample required for each assay element. In this dissertation, new HTS techniques for enzyme activity analysis were developed. First, patterns of immobilized enzyme on nylon screen were detected by multiplexed capillary system. The imaging resolution is limited by the outer diameter of the capillaries. In order to get finer images, capillaries with smaller outer diameters can be used to form the imaging probe. Application of capillary electrophoresis allows separation of the product from the substrate in the reaction mixture, so that the product doesn't have to have different optical properties with the substrate. UV absorption detection allows almost universal detection for organic molecules. Thus, no modifications of either the substrate or the product molecules are necessary. This technique has the potential to be used in screening of local distribution variations of specific bio-molecules in a tissue or in screening of multiple immobilized catalysts. Another high-throughput screening technique is developed by directly monitoring the light intensity of the immobilized-catalyst surface using a scientific charge-coupled device (CCD). Briefly, the surface of enzyme microarray is focused onto a scientific CCD using an objective lens. By carefully choosing the detection wavelength, generation of product on an enzyme spot can be seen by the CCD. Analyzing the light intensity change over time on an enzyme spot can give information of reaction rate. The same microarray can be used for many times. Thus, high-throughput kinetic studies of hundreds of catalytic reactions are made possible. At last, we studied the fluorescence emission spectra of ADP and obtained the detection limits for ADP under three different

  18. Metabolic Activity of Bacteria at High Pressure

    Picard, A.; Daniel, I.; Oger, P.

    2008-12-01

    Over the last 20 years, there has been increasing evidence for the presence of a large number of microbes in the oceanic subsurface. Such a habitat has a very low energy input because it is deprived of light. A few meters below the sediment surface, conditions are already anoxic in most cases, sulfate reduction and/or methanogenesis becoming thus the primary respiratory reactions of organic matter. Neither the fate of methanogenesis, nor the fate of Dissimilatory Metal-Reduction (DMR) has been investigated so far as a function of pressure. For this reason, we measured experimentally the pressure limits of microbial anaerobic energetic metabolism. In practice, we measured in situ the kinetics of selenite respiration by the bacterial model Shewanella oneidensis MR-1 under high hydrostatic pressure (HHP) between 0 and 150 MPa at 30°C. MR-1 stationary-phase cells were used in Luria-Bertani (LB) medium amended with lactate as an additional electron donor and sodium selenite as an electron acceptor. In situ measurements were performed by X- ray Absorption Near-Edge Structure (XANES) spectroscopy in both a diamond-anvil cell and an autoclave. A red precipitate of amorphous Se(0) was virtually observed at any pressure to 150 MPa. A progressive reduction of selenite Se(IV) into selenium Se(0) was also observed in the evolution of XANES spectra with time. All kinetics between 0.1 and 150 MPa can be adjusted to a first order kinetic law. MR-1 respires all available selenite up to 60 MPa. Above 60 MPa, the respiration yield decreases linearly as a function of pressure and reaches 0 at 155 ±5 MPa. This indicates that selenite respiration by Shewanella oneidensis MR-1 stops at about 155 MPa, whereas its growth is arrested at 50 MPa. Hence, the present results show that the respiration of selenium by the strain MR-1 occurs efficiently up to 60 MPa and 30°C, i.e. from the surface of a continental sediment to an equivalent depth of about 2 km, or beneath a 5-km water column and

  19. Selective High Impedance Surface Active Region Loading of Archimedean Spiral Antenna

    Mohamad, Sarah; Cahill, Robert; Fusco, Vincent

    2014-01-01

    We show that a significant increase in the gain and front-to-back ratio is obtained when different high impedance surface (HIS) sections are placed below the active regions of an Archimedean spiral antenna. The principle of operation is demonstrated at 3, 6, and 9 GHz for an antenna design that employs a ground plane composed of two dissimilar HISs. The unit cells of the HISs are collocated and resonant at the same frequency as the 3- and 6-GHz active regions of the wideband spiral. It is sho...

  20. Active video games as a tool to prevent excessive weight gain in adolescents : rationale, design and methods of a randomized controlled trial

    Simons, Monique; Mai J M Chinapaw; van de Bovenkamp, Maaike; de Boer, Michiel R; Jacob C Seidell; Brug, Johannes; Vet, Emely

    2014-01-01

    Background: Excessive body weight, low physical activity and excessive sedentary time in youth are major public health concerns. A new generation of video games, the ones that require physical activity to play the games -i.e. active games- may be a promising alternative to traditional non-active games to promote physical activity and reduce sedentary behaviors in youth. The aim of this manuscript is to describe the design of a study evaluating the effects of a family oriented active game inte...

  1. Gain Shift Corrections at Chi-Nu

    Brown, Tristan Brooks [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Massachusetts, Lowell, MA (United States). Dept. of Physics and Applied Physics; Devlin, Matthew James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-30

    Ambient conditions have the potential to cause changes in liquid scintillator detector gain that vary with time and temperature. These gain shifts can lead to poor resolution in both energy as well as pulse shape discrimination. In order to correct for these shifts in the Chi-Nu high energy array, a laser system has been developed for calibration of the pulse height signals.

  2. Carnosic acid-rich rosemary (Rosmarinus officinalis L.) leaf extract limits weight gain and improves cholesterol levels and glycaemia in mice on a high-fat diet

    Chiralt Boix, Mª Amparo; Cases, Julien; Coussaert, Aurélie Coussaert; Roller, Marc; Ripoll, Christophe

    2011-01-01

    Rosemary (Rosmarinus officinalis L.) extracts (RE) are natural antioxidants that are used in food, food supplements and cosmetic applications; exert anti-inflammatory and anti-hyperglycaemic effects; and promote weight loss, which can be exploited to develop new preventive strategies against metabolic disorders. Therefore, the aim of the present study was to evaluate the preventive effects of rosemary leaf extract that was standardised to 20 % carnosic acid (RE) on weight gain, glucose levels...

  3. Targeting Binge Eating for the Prevention of Excessive Weight Gain: Interpersonal Psychotherapy for Adolescents at High-Risk for Adult Obesity

    Tanofsky-Kraff, Marian; Wilfley, Denise E.; Young, Jami F.; Mufson, Laura; Yanovski, Susan Z.; Glasofer, Deborah R.; Salaita, Christine G.

    2007-01-01

    The most prevalent disordered eating pattern described in overweight youth is loss of control (LOC) eating, during which individuals experience an inability to control the type or amount of food they consume. LOC eating is associated cross-sectionally with greater adiposity in children and adolescents, and appears to predispose youth to gain weight or body fat above that expected during normal growth, thus likely contributing to obesity in susceptible individuals. No prior studies have examin...

  4. Ablation of TRPM5 in Mice Results in Reduced Body Weight Gain and Improved Glucose Tolerance and Protects from Excessive Consumption of Sweet Palatable Food when Fed High Caloric Diets.

    Marie H Larsson

    Full Text Available The calcium activated cation channel transient receptor potential channel type M5 (TRPM5 is part of the downstream machinery of the taste receptors and have been shown to play a central role in taste signalling. In addition it is also found in other types of chemosensory cells in various parts of the body as well as in pancreatic β-cells. The aim of this study was to investigate the effects of TRPM5 gene ablation on body weight, insulin sensitivity and other metabolic parameters in long-term high caloric diet induced obesity. Trpm5-/- mice gained significantly less body weight and fat mass on both palatable carbohydrate and fat rich cafeteria diet and 60% high fat diet (HFD and developed less insulin resistance compared to wild type mice. A main finding was the clearly improved glucose tolerance in Trpm5-/- mice compared to wild type mice on cafeteria diet, which was independent of body weight. In addition, it was shown that Trpm5-/- mice consumed the same amount of calories when fed a HFD only or a HFD in combination with a palatable chocolate ball, which is in contrast to wild type mice that increased their caloric intake when fed the combination, mainly due to excessive consumption of the chocolate ball. Thus the palatable sugar containing diet induced overeating was prevented in Trpm5-/- mice. This indicates that sweet taste induced overeating may be a cause for the increased energy intake and glucose intolerance development seen for wild type mice on a sugar and high fat rich cafeteria diet compared to when on a high fat diet. This study point to an important role for the taste signalling system and TRPM5 in diet induced glucose intolerance.

  5. A low-power high-performance configurable auto-gain control loop for a digital hearing aid SoC

    A low-power, configurable auto-gain control loop for a digital hearing aid system on a chip (SoC) is presented. By adopting a mixed-signal feedback control structure and peak detection and judgment, it can work in automatic gain or variable gain control modes through a digital signal processing unit. A noise-reduction and dynamic range (DR) improvement technique is also used to ensure the DR of the circuit in a low-voltage supply. The circuit is implemented in an SMIC 0.13 μm 1P8M CMOS process. The measurement results show that in a 1 V power supply, 1.6 kHz input frequency and 200 mVp—p, the SFDR is 74.3 dB, the THD is 66.1 dB, and the total power is 89 μW, meeting the application requirements of hearing aid SoCs. (semiconductor integrated circuits)

  6. Active video games as a tool to prevent excessive weight gain in adolescents : rationale, design and methods of a randomized controlled trial

    Simons, Monique; Chinapaw, Mai J M; van de Bovenkamp, Maaike; de Boer, Michiel R; Seidell, Jacob C; Brug, Johannes; de Vet, Emely

    2014-01-01

    BACKGROUND: Excessive body weight, low physical activity and excessive sedentary time in youth are major public health concerns. A new generation of video games, the ones that require physical activity to play the games--i.e. active games--may be a promising alternative to traditional non-active gam

  7. Active video games as a tool to prevent excessive weight gain in adolescents: Rationale, design and methods of a randomized controlled trial

    Simons, M.; Chinapaw, M.J.; Bovenkamp, M. van de; Boer, M.R. de; Seidell, J.C.; Brug, J.; Vet, E. de

    2014-01-01

    Background: Excessive body weight, low physical activity and excessive sedentary time in youth are major public health concerns. A new generation of video games, the ones that require physical activity to play the games -i.e. active games- may be a promising alternative to traditional non-active gam

  8. Active video games as a tool to prevent excessive weight gain in adolescents: rationale, design and methods of a randomized controlled trial

    Simons, M.; Chinapaw, M.J.M.; Bovenkamp, van de M.; Boer, de M.R.; Seidell, J.C.; Brug, J.; Vet, de E.

    2014-01-01

    Background Excessive body weight, low physical activity and excessive sedentary time in youth are major public health concerns. A new generation of video games, the ones that require physical activity to play the games –i.e. active games- may be a promising alternative to traditional non-active game

  9. Theoretical investigation of the more suitable rare earth to achieve high gain in waveguide based on silica containing silicon nanograins doped with either Nd3+ or Er3+ ions

    Fafin, Alexandre; Dufour, Christian; Gourbilleau, Fabrice

    2014-01-01

    We present a comparative study of the gain achievement in a waveguide whose active layer is constituted by a silica matrix containing silicon nanograins acting as sensitizer of either neodymium ions (Nd3+) or erbium ions (Er3+). By means of an auxiliary differential equation and finite difference time domain (ADE-FDTD) approach that we developed, we investigate the steady states regime of both rare earths ions and silicon nanograins levels populations as well as the electromagnetic field for different pumping powers ranging from 1 to 104 mW/mm2. Moreover, the achievable gain has been estimated in this pumping range. The Nd3+ doped waveguide shows a higher gross gain per unit length at 1064 nm (up to 30 dB/cm) than the one with Er3+ doped active layer at 1532 nm (up to 2 dB/cm). Taking into account the experimental background losses we demonstrate that a significant positive net gain can only be achieved with the Nd3+ doped waveguide.

  10. Coupled-inductor-boost high voltage gain converter with a nondissipative LC snubber%基于 LC 吸收电路的耦合电感高升压增益变换器

    陈章勇; 许建平; 吴建雪

    2015-01-01

    A Coupled-Inductor-Boost high voltage gain converter with a nondissipative LC snubber was presented . By utilizing a snubber circuit composed of capacitor, inductor and diode, leakage inductance energy was recycled and voltage spike stress of the power switch was suppressed. Compared with active clamp circuit or lossless snubber circuit, the proposed converter maintains the characteristics of continu-ous input current and therefore makes it easy to design electromagnetic interference (EMI) filter. Mean-while, the converter with single power switch and high voltage gain, has appropriate candidate for photo-voltaic, fuel cells and other renewable energy system application. Steady state analysis of the converter and operating characteristics was developed. Finally, experimental results from a 100W 45V/ 200V proto-type were presented to verify the analysis of the proposed converter.%提出一种带无源无损 LC 吸收电路的耦合电感高增益升压变换器,采用电容、电感和二极管组成的无源吸收电路网络,回收了变换器中漏感能量,同时抑制了开关管两端的电压尖峰,从而减小了开关管的电压应力。与传统有源箝位或无源吸收电路相比,具有 LC 吸收电路的耦合电感Boost 变换器的输入电流连续,简化了输入滤波器的设计。同时,该变换器仅有一个开关管,且通过调节耦合电感变比可实现高升压增益特性,在新能源领域具有广泛的应用前景。文中详细分析了该变换器的工作原理及工作特性,最后通过搭建一台100 W、45 V/200 V 的实验样机,验证了理论分析的正确性。

  11. Broadband high efficiency active integrated antenna

    Qin, Yi

    2007-01-01

    Active integrated antenna (MA) is a very popular topic of research during recent decades. This is mostly due to its advantages, such as compact size, multiple functions and low cost, etc. The MA system can be regarded as an active microwave circuit which the output or input port is free space instead of a conventional 50-ohm interface. The major drawbacks of the conventional MA include narrow bandwidth, low efficiency, etc. An experimental investigation on broadband slot-coupled antenna is ca...

  12. Gaining Relational Competitive Advantages

    Hu, Yimei; Zhang, Si; Li, Jizhen;

    2015-01-01

    Establishing strategic technological partnerships (STPs) with foreign partners is an increasingly studied topic within the innovation management literature. Partnering firms can jointly create sources of relational competitive advantage. Chinese firms often lack research and development (R......&D) capabilities but are increasingly becoming preferred technological partners for transnational corporations. We investigate an STP between a Scandinavian and a Chinese firm and try to explore how to gain relational competitive advantage by focusing on its two essential stages: relational rent generation and...... appropriation. Based on an explorative case study, we develop a conceptual framework that consists of process, organizational alliance factors, and coordination modes that we propose lead to relational competitive advantage....

  13. Graphene as Gain Medium for Broadband Lasers

    Jago, Roland; Winzer, T.; Knorr, A.; Malic, Ermin

    2014-01-01

    Efficient nonradiative carrier recombination strongly counteracts the appearance of optical gain in graphene. Based on a microscopic and fully quantum-mechanical study of the coupled carrier, phonon, and photon dynamics in graphene, we present a strategy to obtain a long-lived gain: Integrating graphene into a high quality photonic crystal nanocavity and applying a high-dielectric substrate suppresses the nonradiative recombination channels and gives rise to pronounced coherent light emission...

  14. [Fast food promotes weight gain].

    Stender, Steen; Dyerberg, Jørn; Astrup, Arne V

    2007-05-01

    The total amounts of fat in a fast food menu consisting of French fries and fried Chicken Nuggets from McDonald's and KFC, respectively, bought in 35 different countries vary from 41 to 71 gram. In most countries the menu contained unacceptably high amounts of industrially-produced trans fat which contributes to an increased risk of ischaemic heart disease, weight gain, abdominal fat accumulation and type 2 diabetes. The quality of the ingredients in fast food ought to be better and the size of the portions smaller and less energy-dense so that frequent fast food meals do not increase the risk of obesity and diseases among customers. PMID:17537359

  15. Gaining and sustaining schistosomiasis control

    Ezeamama, Amara E; He, Chun-La; Shen, Ye;

    2016-01-01

    strategies. RESULTS: These studies of different treatment schedules with PZQ will provide the most comprehensive data thus far on the optimal frequency and continuity of PCT for schistosomiasis infection and morbidity control. CONCLUSIONS: We expect that the study outcomes will provide data for decision...... 2009, SCORE held a series of meetings to specify empirical questions and design studies related to different schedules of PCT for schistosomiasis control in communities with high (gaining control studies) and moderate (sustaining control studies) prevalence of Schistosoma infection among school...

  16. Gain optimization method of a DQW superluminescent diode with broad multi-state emission

    Dimas, Clara E.

    2010-01-01

    Optimizing gain through systematic methods of varying current injection schemes analytically is significant to maximize experimentally device yield and evaluation. Various techniques are used to calculate the amplified spontaneous emission (ASE) gain for light emitting devices consisting of single-section and multiple-sections of even length. Recently double quantum well (DQW) superluminescent diodes (SLD) have shown a broad multi-state emission due to mutlielectrodes of non-equal lengths and at high non-equal current densities. In this study, we adopt an improved method utilizing an ASE intensity ratio to calibrate a gain curve based on the sum of the measured ASE spectra to efficiently estimate the gain. Although the laser gain for GaAs/AlGaAs material is well studied, the ASE gain of SLD devices has not been systematically studied particular to further explain the multiple-state emission observed in fabricated devices. In addition a unique gain estimate was achieved where the excited state gain clamps prior to the ground state due to approaching saturation levels. In our results, high current densities in long sectioned active regions achieved sufficient un-truncated gain that show evidence of excited state emission has been observed.

  17. Single crystalline Er{sub 2}O{sub 3}:sapphire films as potentially high-gain amplifiers at telecommunication wavelength

    Kuznetsov, A. S.; Sadofev, S.; Schäfer, P.; Kalusniak, S.; Henneberger, F., E-mail: fh@physik.hu-berlin.de [Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin (Germany)

    2014-11-10

    Single crystalline thin films of Er{sub 2}O{sub 3}, demonstrating efficient 1.5 μm luminescence of Er{sup 3+} at room temperature were grown on Al{sub 2}O{sub 3} substrate by molecular beam epitaxy. The absorption coefficient at 1.536 μm was found to reach 270 cm{sup −1} translating in a maximal possible gain of 1390 dBcm{sup −1}. In conjunction with the 10% higher refractive index as compared to Al{sub 2}O{sub 3}, this opens the possibility to use Er{sub 2}O{sub 3}:sapphire films as short-length waveguide amplifiers in telecommunication.

  18. Application of Mathematical Modeling Activities in Costarican High School Education

    Karen Porras-Lizano

    2015-01-01

    Full Text Available This paper describes the experience gained in implementing mathematical modeling activities as a methodological strategy in teaching issues such as proportions, with a group of eighth year of an academic-day-school, located in the province of San Jose, Costa Rica in 2012. Different techniques for gathering information were applied, such as participant observation and questionnaires. Among the relevant results are the cyclical development of mathematical thinking of students in the stages of mathematical modeling (description, manipulation, prediction and validation for solving the problem; developing of teamwork skills; and appreciation of mathematics as a useful and effective discipline. To resolve the activities proposed in this study, social interactions such as sharing information, thoughts and ideas, were generated, stimulating the zone of proximal development of the participating students. Likewise, the mathematical modeling activities allowed students to have a positive role in mathematics classes, stimulating, in turn, a different attitude compared to regular classes.

  19. Sudden gains in psychotherapy

    Auður Sjöfn Þórisdóttir 1986

    2014-01-01

    Verkefni þetta samanstendur af fræðilegu yfirliti og rannsóknagrein til birtingar í vísindatímarit. Verkefnið fjallar um tiltekið mynstur breytinga á einkennum geðraskana í sálfræðimeðferð, sem kallast skyndiframfarir (e. sudden gains) og þekkist af skyndilegum og miklum breytingum á einkennum milli tveggja meðferðartíma. Í fræðilega yfirlitinu er farið yfir hvernig þetta breytingamynstur hefur verið skilgreint og skýrt og sagt frá helstu niðurstöðum rannsókna á þessu sviði. Fjallað er um ann...

  20. Active noise control for high frequencies

    Kaymak, E; Atherton, MA; Rotter, KRG; Millar, B.

    2006-01-01

    There are many applications that can benefit from Active Noise Control (ANC) such as in aircraft cabins and air conditioning ducts, i.e. in situations where technology interferes with human hearing in a harmful way or disrupts communication. Headsets with analogue ANC circuits have been used in the armed forces for attenuating frequencies below 1 kHz, which when combined with passive filtering offers protection across the whole frequency range of human hearing. A dental surgery is also a nois...

  1. Gain control mechanisms in spinal motoneurons

    Michael David Johnson

    2014-07-01

    Full Text Available Motoneurons provide the only conduit for motor commands to reach muscles. For many years, motoneurons were in fact considered to be little more than passive wires. Systematic studies in the past 25 years however have clearly demonstrated that the intrinsic electrical properties of motoneurons are under strong neuromodulatory control via multiple sources. The discovery of potent neuromodulation from the brainstem and its ability to change the gain of motoneurons shows that the passive view of the motor output stage is no longer tenable. A mechanism for gain control at the motor output stage makes good functional sense considering our capability of generating an enormous range of forces, from very delicate (e.g. putting in a contact lens to highly forceful (emergency reactions. Just as sensory systems need gain control to deal with a wide dynamic range of inputs, so to might motor output need gain control to deal with the wide dynamic range of the normal movement repertoire. Two problems emerge from the potential use of the brainstem monoaminergic projection to motoneurons for gain control. First, the projection is highly diffuse anatomically, so that independent control of the gains of different motor pools is not feasible. In fact, the system is so diffuse that gain for all the motor pools in a limb likely increases in concert. Second, if there is a system that increases gain, probably a system to reduce gain is also needed. In this review, we summarize recent studies that show local inhibitory circuits within the spinal cord, especially reciprocal and recurrent inhibition, have the potential to solve both of these problems as well as constitute another source of gain modulation.

  2. Assess the key physics that underpins high-hydro coupling-efficiency in NDCX-II experiments and high-gain heavy ion direct drive target designs using proven hydro codes like HYDRA

    Barnard, J. J.; Hay, M. J.; Logan, B. G.; Ng, S. F.; Perkins, L. J.; Veitzer, S.; Yu, S. S.

    2010-07-01

    also used for ID (planar) and 2D (r,z) simulations of potential experiments. We have also explored whether similar physics could be studied using an energy ramp (i.e., a velocity tilt) rather than two separate pulses. We have shown that an optimum occurs in the macropulse duration (with fixed velocity tilt) that maximizes the shock strength. In the area of IFE target design we have continued to explore direct drive targets composed of deuterium-tritium fuel and ablator layers. We have extended our previous target designs at 0.44 MJ drive energy, gain 50, (50 MeV foot, 500 MeV main pulse, Rb ion, which requires a large number of beams due to a high beam space charge constraint) to a power plant scale 3.7 MJ drive energy, gain {approx}150 (220 MeV foot, 2.2 GeV main pulse, Hg ion) that eases requirements on the accelerator. We have studied the effects of two important design choices on ICF target performance. We have shown that increasing the number of foot pulses may reduce the target's in-flight adiabat and consequently improve its compressibility and fusion yield. As in the case of laser drive, the first three shocks are the most important to the target's performance, with additional shocks contributing only marginally to compression and burn. We have also demonstrated that ion range lengthening during the main pulse can further reduce the target adiabat and improve the efficiency with which beam energy is coupled into the target. (Ion range lengthening using two different kinetic energies for the foot and main pulse has previously proven effective in the design of high gain targets).

  3. Relative contributions of energy expenditure on physical activity, body composition and weight gain to the evolution of impaired glucose tolerance to Frank diabetes. Highlights and achievements

    The effect of obesity on glucose intolerance is a mixture of the impact of body composition on glucose-insulin relationships as well as the modulation of this metabolism by physical activity. Populations of the African diaspora in the Caribbean and the United States have higher levels of obesity, glucose intolerance and diabetes than the ancestral population in West Africa. This is most likely a consequence of lifestyle changes, including an apparent decline in physical activity and dietary changes

  4. Development of CNS Active Target for Deuteron Induced Reactions with High Intensity Exotic Beam

    Ota, Shinsuke; Tokieda, H.; Lee, C. S.; Kojima, R.; Watanabe, Y. N.; Corsi, A.; Dozono, M.; Gibelin, J.; Hashimoto, T.; Kawabata, T.; Kawase, S.; Kubono, S.; Kubota, Y.; Maeda, Y.; Matsubara, H.; Matsuda, Y.; Michimasa, S.; Nakao, T.; Nishi, T.; Obertelli, A.; Otsu, H.; Santamaria, C.; Sasano, M.; Takaki, M.; Tanaka, Y.; Leung, T.; Uesaka, T.; Yako, K.; Yamaguchi, H.; Zenihiro, J.; Takada, E.

    An active target system called CAT, has been developed aiming at the measurement of deuteron induced reactions with high intensity beams in inverse kinematics. The CAT consists of a time projection chamber using THGEM and an array of Si detectors or NaI scintilators. The effective gain for the recoil particle is deisgned to be 5 - 10 × 103, while one for the beam is reduced by 102 using mesh grid to match the amplified signal to the dynamic range same as the one for recoil particle. The structure of CAT and the effect of the mesh grid are reported.

  5. Relative contributions of energy expenditure on physical activity, body composition and weight gain to the evolution of impaired glucose tolerance to Frank diabetes. Highlights and achievements

    There is a gradient of diabetes prevalence among populations of the African Diaspora. HYPOTHESIS: The risk of diabetes in transitional populations of the African diaspora is directly related to the rate of anthropornetric change and physical activity. AIMS: - To determine whether risk of incident diabetes and impaired glucose tolerance is related to physical activity in two populations of the African Diaspora with widely different levels of obesity; - To determine whether risk of incident diabetes and impaired glucose tolerance is related to rate of rise in body weight and change in body composition

  6. Teacher-and child-managed academic activities in preschool and kindergarten and their influence on children's gains in emergent academic skills

    De Haan, Annika K E; Elbers, Ed; Leseman, Paul P M

    2014-01-01

    The aim of this study was to assess whether children's development benefited from teacher-and child-managed academic activities in the preschool and kindergarten classroom. Extensive systematic observations during four half-days in preschool (n = 8) and kindergarten (n = 8) classrooms revealed that

  7. Cash and in-kind transfers lead to excess weight gain in a population of women with a high prevalence of overweight in rural Mexico.

    Leroy, Jef L; Gadsden, Paola; González de Cossío, Teresa; Gertler, Paul

    2013-03-01

    There is a growing concern that food or cash transfer programs may contribute to overweight and obesity in adults. We studied the impact of Mexico's Programa de Apoyo Alimentario (PAL), which provided very poor rural households with cash or in-kind transfers, on women's body weight. A random sample of 208 rural communities in southern Mexico was randomly assigned to 1 of 4 groups: food basket with or without health and nutrition education, cash with education, or control. The impact on women's weight was estimated in a cohort of 3010 women using a difference-in-difference model. We compared the impact between the food basket and cash groups and evaluated whether the impact was modified by women's BMI status at baseline. With respect to the control group, the program increased women's weight in the food basket (550 ± 210 g; P = 0.004) and the cash group (420 ± 230 g; P = 0.032); this was equivalent to 70 and 53% increases in weight gain, respectively, over that observed in the control group in a 23-mo time period. The greatest impact was found in already obese women: 980 ± 290 g in the food basket group (P = 0.001) and 670 ± 320 g in the cash group (P = 0.019). Impact was marginally significant in women with a preprogram BMI between 25 and 30 kg/m2: 490 ± 310 g (P = 0.055) and 540 ± 360 g (P = 0.067), respectively. No program impact was found in women with a BMI programs such as PAL and to help beneficiaries choose healthy diets that improve the nutritional status of all family members. PMID:23343672

  8. Obesity-prone high-fat-fed rats reduce caloric intake and adiposity and gain more fat-free mass when allowed to self-select protein from carbohydrate:fat intake.

    Azzout-Marniche, Dalila; Chalvon-Demersay, Tristan; Pimentel, Grégory; Chaumontet, Catherine; Nadkarni, Nachiket A; Piedcoq, Julien; Fromentin, Gilles; Tomé, Daniel; Gaudichon, Claire; Even, Patrick C

    2016-06-01

    We tested the hypothesis that, for rats fed a high-fat diet (HFD), a prioritization of maintaining protein intake may increase energy consumption and hence result in obesity, particularly for individuals prone to obesity ("fat sensitive," FS, vs. "fat resistant," FR). Male Wistar rats (n = 80) first received 3 wk of HFD (protein 15%, fat 42%, carbohydrate 42%), under which they were characterized as being FS (n = 18) or FR (n = 20) based on body weight gain. They then continued on the same HFD but in which protein (100%) was available separately from the carbohydrate:fat (50:50%) mixture. Under this second regimen, all rats maintained their previous protein intake, whereas intake of fat and carbohydrate was reduced by 50%. This increased protein intake to 26% and decreased fat intake to 37%. Adiposity gain was prevented in both FR and FS rats, and gain in fat-free mass was increased only in FS rats. At the end of the study, the rats were killed 2 h after ingestion of a protein meal, and their tissues and organs were collected for analysis of body composition and measurement of mRNA levels in the liver, adipose tissue, arcuate nucleus, and nucleus accumbens. FS rats had a higher expression of genes encoding enzymes involved in lipogenesis in the liver and white adipose tissue. These results show that FS rats strongly reduced food intake and adiposity gain through macronutrient selection, despite maintenance of a relatively high-fat intake and overexpression of genes favoring lipogenesis. PMID:27030668

  9. Cationic zinc enolates as highly active catalysts for acrylate polymerization.

    Garner, Logan E; Zhu, Hongping; Hlavinka, Mark L; Hagadorn, John R; Chen, Eugene Y-X

    2006-11-22

    Unprecedented cationic zinc enolates have been generated by a novel activation route involving the amido to imino ligand transformation with B(C6F5)3, structurally characterized, and utilized as highly active catalysts for the production of high molecular weight polyacrylates at ambient temperature. PMID:17105289

  10. Gain modulation by graphene plasmons in aperiodic lattice lasers

    Chakraborty, S.; Marshall, O. P.; Folland, T. G.; Kim, Y.-J.; Grigorenko, A. N.; Novoselov, K. S.

    2016-01-01

    Two-dimensional graphene plasmon-based technologies will enable the development of fast, compact, and inexpensive active photonic elements because, unlike plasmons in other materials, graphene plasmons can be tuned via the doping level. Such tuning is harnessed within terahertz quantum cascade lasers to reversibly alter their emission. This is achieved in two key steps: first, by exciting graphene plasmons within an aperiodic lattice laser and, second, by engineering photon lifetimes, linking graphene’s Fermi energy with the round-trip gain. Modal gain and hence laser spectra are highly sensitive to the doping of an integrated, electrically controllable, graphene layer. Demonstration of the integrated graphene plasmon laser principle lays the foundation for a new generation of active, programmable plasmonic metamaterials with major implications across photonics, material sciences, and nanotechnology.

  11. Reducing gain shifts in photomultiplier tubes

    Cohn, Charles E.

    1976-01-01

    A means is provided for reducing gain shifts in multiplier tubes due to varying event count rates. It includes means for limiting the number of cascaded, active dynodes of the multiplier tube to a predetermined number with the last of predetermined number of dynodes being the output terminal of the tube. This output is applied to an amplifier to make up for the gain sacrificed by not totally utilizing all available active stages of the tube. Further reduction is obtained by illuminating the predetermined number of dynodes with a light source of such intensity that noise appearing at the output dynode associated with the illumination is negligible.

  12. Noise Temperature Characteristics and Gain-control of Avalanche Photodiodes for Laser Radar

    CAI Xi-ping; SHANG Hong-Bo; BAI Ji-yuan; YANG Shuang; WANG Li-na

    2008-01-01

    Avalanche photodiodes(APDs) are promising light sensors with high quantum efficiency and low noise. It has been extensively used in radiation detection, laser radar and other weak signal detection fields. Unlike other photodiodes, APD is a very sensitive light detector with very high internal gain. The basic theory shows that the gain of APD is related to the temperature. The internal gain fluctuates with the variation of temperature. Investigated was the influence of the variation of the gain induced by the fluctuation of temperature on the output from APD for a very weak laser pulse input in laser radar. An active reverse-biased voltage compensation method is used to stabilize the gain of APD. An APD model is setup to simulate the detection of light pulse signal. The avalanche process, various noises and temperature's effect are all included in the model. Our results show that for the detection of weak light signal such as in laser radar, even a very small fluctuation of temperature could cause a great effect on APD's gain. The results show that the signal-to-noise ratio of the APD's output could be improved effectively with the active gain-control system.

  13. Asthma Triggers: Gain Control

    ... comes from car exhaust, smoke, road dust and factory emissions. Outdoor air quality is also affected by pollen from plants, crops and weeds. Particle pollution can be high any time of year and ...

  14. Gain Flattening Filter Canceling Temperature Dependence of EDFA s gain

    M.; Ohmura; Y.; Ishizawa; H.; Nakaji; K.; Hashimoto; T.; Shibata; M.; Shigehara; A.; Inoue

    2003-01-01

    We have developed a gain flattening filter (GFF) for an erbium doped fiber (EDF) without temperature control systems. This GFF, which consists of temperature-sensitive long period gratings (LPGs) and a temperature compensated slanted fiber Bragg grating (SFBG), follows the gain shift of EDF with temperature. Gain variation of the EDFA less than 0.25dBp-p was achieved with the bandwidth of 37nm, and the temperature range 0-65℃ without any temperature control systems.

  15. Relative contributions of energy expenditure on physical activity, body composition and weight gain to the evolution of impaired glucose to tolerance to Frank diabetes

    There is a gradient of diabetes prevalence among populations of the African Diaspora, with a rate of about 1% in West Africa, 12% in Jamaica and 16% in the United States. A population-based survey was conducted in an urban community in Jamaica to document the risk factors for the evolution of impaired glucose tolerance to frank diabetes. In a sample of 614 adults, 239 men and 375 women, oral glucose tolerance tests and examinations were conducted at Baseline and after 4-years of Follow-Up. There were significant increases in virtually all weight and adiposity variables for both men and women. Energy expenditure was also measured in a subset of participants at Follow-Up and was related significantly to glucose tolerance status. Among men, baseline age, weight, fat mass, body fat, waist circumference, and change in waist circumference were predictive of worsening glucose tolerance status. Among women, only age and change in waist circumference was a significant predictor. No physical activity parameter was predictive of change in tolerance status. These results provide support for the need to decrease adiposity as an important mechanism to control the rise in diabetes prevalence. (author)

  16. Gain and energy storage in holmium YLF

    Storm, Mark E.; Deyst, John P.

    1991-01-01

    It is demonstrated that Q-switched holmium lasers are capable of high-gain and high-energy operation at 300 K. Small-signal gain coefficients of 0.50 and 0.12/cm have been measured in YLF and YAG, respectively. Small-signal gains of 0.50/cm are comparable to those achievable in Nd:YAG and are not typical of low-gain materials. This large gain in the Ho:YLF material is made possible by operating the amplifier in the ground state depletion mode. The amplifier performance data and associated analysis presented demonstrate that efficient energy storage is possible with very high excited state ion densities of the Ho 5I7 upper laser level. This is an important result since upconversion can limit the 5I7 population. Although upconversion was still present in this experiment, it was possible to achieve efficient energy storage, demonstrating that the problem is manageable even at high excitation densities in YLF.

  17. Lower weight gain and hepatic lipid content in hamsters fed high fat diets supplemented with white rice protein, brown rice protein, and soy protein and their hydrolysates

    The physiological effects of the hydrolysates from white rice, brown rice, and soy isolate were compared to the original protein source. White rice, brown rice, and soy protein were hydrolyzed with the food grade enzyme, alcalase2.4 L®. Male Syrian hamsters were fed high-fat diets containing eithe...

  18. High resolution radar rainfall for urban pluvial flood managementmanagement: Lessons learnt from 10 pilots in North-West Europe within the RainGain project

    Ten Veldhuis, J.A.E.; Ochoa-Rodriguez, S.; Bruni, G.; Gires, A.; Van Assel, J.; Ichaba, A.; Kroll, S.; Wang, L.P.; Tchiguirinskaia, I.; Giangola Murzyn, A.; Richard, J.; Schertzer, D.; Willems, P.

    2014-01-01

    Precipitation and catchment information needs to be available at high resolution to reliably predict hydrological response and potential flooding in urban catchments. While recent advances have been made in weather radar technology and availability of DTM for urban flood modelling, the question is w

  19. Saving and gaining energy

    In this interview with Dirk U. Hindrichs from the Schueco International KG company, differences between ecological and economical points of view in general are discussed, as is the world's energy consumption and the visions held by the Schueco company in this respect. The importance of building facades, windows and photovoltaics for his business is discussed, as are solar thermal systems for the production of heat and cold. Further, energy-efficiency and examples of buildings realised internationally are discussed and co-operation with important players in the climate protection area is noted. Hindrichs' opinion, that pro-active actions must be taken by entrepreneurs, is noted.

  20. Intraperitoneal Injection of Clodronate Liposomes Eliminates Visceral Adipose Macrophages and Blocks High-fat Diet-induced Weight Gain and Development of Insulin Resistance

    Bu, Le; Gao, Mingming; Qu, Shen; Liu, Dexi

    2013-01-01

    Macrophage infiltration in adipose tissue is strongly correlated with obesity. The exact role of macrophage in the development of obesity, however, has not been fully understood. In this study, using intraperitoneal injection of clodronate liposomes, we tissue-specifically depleted visceral adipose tissue macrophages (VATMs) and explored their roles in initiation and progression of obesity. Two sets of experiments were conducted, using mice on a high-fat diet as the animal model. Mice were in...

  1. Gains in QTL detection using an ultra-high density SNP map based on population sequencing relative to traditional RFLP/SSR markers.

    Huihui Yu

    Full Text Available Huge efforts have been invested in the last two decades to dissect the genetic bases of complex traits including yields of many crop plants, through quantitative trait locus (QTL analyses. However, almost all the studies were based on linkage maps constructed using low-throughput molecular markers, e.g. restriction fragment length polymorphisms (RFLPs and simple sequence repeats (SSRs, thus are mostly of low density and not able to provide precise and complete information about the numbers and locations of the genes or QTLs controlling the traits. In this study, we constructed an ultra-high density genetic map based on high quality single nucleotide polymorphisms (SNPs from low-coverage sequences of a recombinant inbred line (RIL population of rice, generated using new sequencing technology. The quality of the map was assessed by validating the positions of several cloned genes including GS3 and GW5/qSW5, two major QTLs for grain length and grain width respectively, and OsC1, a qualitative trait locus for pigmentation. In all the cases the loci could be precisely resolved to the bins where the genes are located, indicating high quality and accuracy of the map. The SNP map was used to perform QTL analysis for yield and three yield-component traits, number of tillers per plant, number of grains per panicle and grain weight, using data from field trials conducted over years, in comparison to QTL mapping based on RFLPs/SSRs. The SNP map detected more QTLs especially for grain weight, with precise map locations, demonstrating advantages in detecting power and resolution relative to the RFLP/SSR map. Thus this study provided an example for ultra-high density map construction using sequencing technology. Moreover, the results obtained are helpful for understanding the genetic bases of the yield traits and for fine mapping and cloning of QTLs.

  2. Fetal Programming of Obesity: Maternal Obesity and Excessive Weight Gain

    Seray Kabaran

    2014-01-01

    The prevalence of obesity is an increasing health problem throughout the world. Maternal pre-pregnancy weight, maternal nutrition and maternal weight gain are among the factors that can cause childhood obesity. Both maternal obesity and excessive weight gain increase the risks of excessive fetal weight gain and high birth weight. Rapid weight gain during fetal period leads to changes in the newborn body composition. Specifically, the increase in body fat ratio in the early periods is associat...

  3. High-Throughput Screening for Streptomyces Antibiotic Biosynthesis Activators

    Li CHEN; Wang, Yemin; Guo, Hang; Xu, Min; Deng, Zixin; Tao, Meifeng

    2012-01-01

    A genomic cosmid library of Streptomyces clavuligerus was constructed and transferred efficiently by conjugation to Streptomyces lividans, and 12 distinct groups of overlapping cosmid clones that activated the silent actinorhodin biosynthesis gene cluster were identified. This generally applicable high-throughput screening procedure greatly facilitates the identification of antibiotic biosynthesis activators.

  4. Murine erythrocytes contain high levels of lysophospholipase activity

    Kamp, J.A.F. op den; Roelofsen, B.; Sanderink, G.; Middelkoop, E.; Hamer, R.

    1984-01-01

    Murine erythrocytes were found to be unique in the high levels of lysophospholipase activity in the cytosol of these cells. The specific activity of the enzyme in the cytosol of the murine cells is 10-times higher than in the cytosol of rabbit erythrocytes and approximately three orders of magnitude

  5. Moderate doses of conjugated linoleic acid reduce fat gain, maintain insulin sensitivity without impairing inflammatory adipose tissue status in mice fed a high-fat diet

    Serra Francisca

    2010-01-01

    Full Text Available Abstract Background The enrichment of diet with nutrients with potential benefits on body composition is a strategy to combat obesity. Conjugated linoleic acid (CLA due its beneficial effects on body composition and inflammatory processes becomes an interesting candidate, since the promotion and impairment of obesity is closely linked to a low-grade inflammation state of adipose tissue. Previously we reported the favourable effects of moderate doses of CLA mixture on body composition and inflammatory status of adipose tissue in mice fed a standard-fat diet. In the present study we assessed the potential beneficial effects of CLA mixture (cis-9, trans-11 and trans-10, cis-12, 50:50 in mice fed a high-fat diet. Methods Two doses were assayed: 0.15 g (CLA1 and 0.5 g CLA/kg body weight (CLA2 for the first 30 days of the study and then animals received a double amount for another 35 days. Results The lowest dose (CLA1 had minor effects on body composition, plasma parameters and gene expression. However, a clear reduction in fat accumulation was achieved by CLA2, accompanied by a reduction in leptin, adiponectin and non-esterified fatty acids (NEFA plasma concentrations. Insulin sensitivity was maintained despite a slight increase in fasting glucose and insulin plasma concentrations. The study of gene expression both in adipocytes and in the stromal vascular fraction (SVF suggested that CLA may reduce either the infiltration of macrophages in adipose tissue or the induction of expression of pro-inflammatory cytokines. Conclusion In conclusion, the use of moderate doses of an equimolar mix of the two main CLA isomers reduces body fat content, improves plasma lipid profile, maintains insulin sensitivity (despite a moderate degree of hyperinsulinaemia without the promotion of inflammatory markers in adipose tissue of mice fed a high-fat diet.

  6. Drug-induced weight gain.

    Ness-Abramof, Rosane; Apovian, Caroline M

    2005-01-01

    Drug-induced weight gain is a serious side effect of many commonly used drugs leading to noncompliance with therapy and to exacerbation of comorbid conditions related to obesity. Improved glycemic control achieved by insulin, insulin secretagogues or thiazolidinedione therapy is generally accompanied by weight gain. It is a problematic side effect of therapy due to the known deleterious effect of weight gain on glucose control, increased blood pressure and worsening lipid profile. Weight gain may be lessened or prevented by adherence to diet and exercise or combination therapy with metformin. Weight gain is also common in psychotropic therapy. The atypical antipsychotic drugs (clozapine, olanzepine, risperidone and quetiapine) are known to cause marked weight gain. Antidepressants such as amitriptyline, mirtazapine and some serotonin reuptake inhibitors (SSRIs) also may promote appreciable weight gain that cannot be explained solely by improvement in depressive symptoms. The same phenomenon is observed with mood stabilizers such as lithium, valproic acid and carbamazepine. Antiepileptic drugs (AEDs) that promote weight gain include valproate, carbamazepine and gabapentin. Lamotrigine is an AED that is weight-neutral, while topiramate and zonisamide may induce weight loss. PMID:16341287

  7. Evaluation of groundwater residence time in a high mountain aquifer system (Sacramento Mountains, USA): insights gained from use of multiple environmental tracers

    Land, Lewis; Timmons, Stacy

    2016-06-01

    The New Mexico Bureau of Geology and Mineral Resources (USA) has conducted a regional investigation of groundwater residence time within the southern Sacramento Mountains aquifer system using multiple environmental tracers. Results of the tracer surveys indicate that groundwater in the southern Sacramento Mountains ranges in age from less than 1 year to greater than 50 years, although the calculated ages contain uncertainties and vary significantly depending on which tracer is used. A distinctive feature of the results is discordance among the methods used to date groundwater in the study area. This apparent ambiguity results from the effects of a thick unsaturated zone, which produces non-conservative behavior among the dissolved gas tracers, and the heterogeneous character and semi-karstic nature of the aquifer system, which may yield water from matrix porosity, fractures, solution-enlarged conduits, or a combination of the three. The data also indicate mixing of groundwater from two or more sources, including recent recharge originating from precipitation at high elevations, old groundwater stored in the matrix, and pre-modern groundwater upwelling along fault zones. The tracer data have also been influenced by surface-water/groundwater exchange via losing streams and lower elevation springs (groundwater recycling). This study highlights the importance of using multiple tracers when conducting large-scale investigations of a heterogeneous aquifer system, and sheds light on characteristics of groundwater flow systems that can produce discrepancies in calculations of groundwater age.

  8. Evaluation of groundwater residence time in a high mountain aquifer system (Sacramento Mountains, USA): insights gained from use of multiple environmental tracers

    Land, Lewis; Timmons, Stacy

    2016-04-01

    The New Mexico Bureau of Geology and Mineral Resources (USA) has conducted a regional investigation of groundwater residence time within the southern Sacramento Mountains aquifer system using multiple environmental tracers. Results of the tracer surveys indicate that groundwater in the southern Sacramento Mountains ranges in age from less than 1 year to greater than 50 years, although the calculated ages contain uncertainties and vary significantly depending on which tracer is used. A distinctive feature of the results is discordance among the methods used to date groundwater in the study area. This apparent ambiguity results from the effects of a thick unsaturated zone, which produces non-conservative behavior among the dissolved gas tracers, and the heterogeneous character and semi-karstic nature of the aquifer system, which may yield water from matrix porosity, fractures, solution-enlarged conduits, or a combination of the three. The data also indicate mixing of groundwater from two or more sources, including recent recharge originating from precipitation at high elevations, old groundwater stored in the matrix, and pre-modern groundwater upwelling along fault zones. The tracer data have also been influenced by surface-water/groundwater exchange via losing streams and lower elevation springs (groundwater recycling). This study highlights the importance of using multiple tracers when conducting large-scale investigations of a heterogeneous aquifer system, and sheds light on characteristics of groundwater flow systems that can produce discrepancies in calculations of groundwater age.

  9. Experimental studies of high order soliton compression effect and gain characteristics in femtosecond laser pulses E3+r-doped fiber amplifier

    2000-01-01

    Seed laser pulses with average power of 146 μW and pulse duration of 480 fs were amplified to 14.5 mW. The pulse duration was compressed to 260 fs using 6 m high concentration E3+r-doped fiber under forward pumping. The amplified signal pulse energy was 0.691 nJ (corresponding to a peak power of 2 657.7 W) and the repetition rate was 20.84 MHz. Spectrum breakup was observed simultaneously. The spectrum of pulses amplified by 3 m E3+r-doped fiber remains a single peak under different pump power. The amplified pulse duration was compressed abnormally with the increasing pump power using the backward pumping; that is, the amplified pulses were compressed with the increasing pump power under low pump power. When the pump power reached 38 mW, the shortest amplified pulse duration was 309 fs. With further increase in pump power, the amplified pulses began broadening, accompanied by a single peak spectrum under different pump power.

  10. Contribution to the development of numerical tools for the hardening of electronic devices to the neutronic and electromagnetic environment induced by a high power gain shot

    When fusion ignition will be attained inside the target chambers of high energy laser facilities (LMJ-France and NIF-Usa), a harsh environment, composed of nuclear particles and an electromagnetic pulse (EMP) will be induced. All electronic devices located in the vicinity will be sensitive to this environment. In the first part of this work, a simulation method has been developed to evaluate transient currents that will be induced in coaxial cables. The relevance of this model is then discussed thanks to comparisons with experimental results. In a second part, the possibility to simulate the propagation of the EMP, inside and outside such a big structure as a target chamber, using the finite difference in time and domain (FDTD) method is evaluated. The use of a classic FDTD method is impossible for this kind of simulation because of the huge computer resources needed. It is the reason why a 3-dimensional space-time sub-grid method for FDTD has been developed and some massively parallel FDTD calculations have also been performed. (author)

  11. NOX Activity in Brain Aging: Exacerbation by High Fat Diet

    Bruce-Keller, Annadora J.; White, Christy L.; Gupta, Sunita; Knight, Alecia G.; Pistell, Paul J.; Ingram, Donald K.; Morrison, Christopher D.; Keller, Jeffrey N.

    2010-01-01

    This study describes how age and high fat diet affect the profile of NADPH oxidase (NOX). Specifically, NOX activity and subunit expression were evaluated in the frontal cerebral cortex of 7-, 16-, and 24-month old mice following a 4-month exposure to either Western diet (WD, 41% calories from fat) or very high fat lard diet (VHFD, 60% calories from fat). Data reveal a significant effect of age in on NOX activity, and show that NOX activity was only increased by VHFD, and only in 24-month old...

  12. Gain Flattening Filter Canceling Temperature Dependence of EDFA's gain

    M. Ohmura; Y. Ishizawa; H. Nakaji; K. Hashimoto; T. Shibata; M. Shigehara; A. Inoue

    2003-01-01

    We have developed a gain flattening filter(GFF) for an erbium doped fiber (EDF) without temperature control systems. This GFF, which consists of temperature-sensitive long period gratings (LPGs)and a temperature compensated slanted fiber Bragg grating (SFBG), follows the gain shift of EDF with temperature. Gain variation of the EDFA less than 0.25dBp-p was achieved with the bandwidth of 37nm,and the temperature range 0-65℃ without and temperature control systems.

  13. Active Galactic Nuclei as High-Energy Neutrino Sources

    Murase, Kohta

    2015-01-01

    Active galactic nuclei (AGN) are believed to be promising candidates of extragalactic cosmic-ray accelerators and sources, and associated high-energy neutrino and hadronic gamma-ray emission has been studied for many years. We review models of high-energy neutrino production in AGN, and discuss their implications for the latest IceCube observation of the diffuse neutrino intensity.

  14. High physical activity in young children suggests positive effects by altering autoantigen-induced immune activity.

    Carlsson, E; Ludvigsson, J; Huus, K; Faresjö, M

    2016-04-01

    Physical activity in children is associated with several positive health outcomes such as decreased cardiovascular risk factors, improved lung function, enhanced motor skill development, healthier body composition, and also improved defense against inflammatory diseases. We examined how high physical activity vs a sedentary lifestyle in young children influences the immune response with focus on autoimmunity. Peripheral blood mononuclear cells, collected from 55 5-year-old children with either high physical activity (n = 14), average physical activity (n = 27), or low physical activity (n = 14), from the All Babies In Southeast Sweden (ABIS) cohort, were stimulated with antigens (tetanus toxoid and beta-lactoglobulin) and autoantigens (GAD65 , insulin, HSP60, and IA-2). Immune markers (cytokines and chemokines), C-peptide and proinsulin were analyzed. Children with high physical activity showed decreased immune activity toward the autoantigens GAD65 (IL-5, P < 0.05), HSP60 and IA-2 (IL-10, P < 0.05) and also low spontaneous pro-inflammatory immune activity (IL-6, IL-13, IFN-γ, TNF-α, and CCL2 (P < 0.05)) compared with children with an average or low physical activity. High physical activity in young children seems to have positive effects on the immune system by altering autoantigen-induced immune activity. PMID:25892449

  15. Speech perception of noise with binary gains

    Wang, DeLiang; Kjems, Ulrik; Pedersen, Michael Syskind;

    2008-01-01

    For a given mixture of speech and noise, an ideal binary time-frequency mask is constructed by comparing speech energy and noise energy within local time-frequency units. It is observed that listeners achieve nearly perfect speech recognition from gated noise with binary gains prescribed by the i...... by the ideal binary mask. Only 16 filter channels and a frame rate of 100 Hz are sufficient for high intelligibility. The results show that, despite a dramatic reduction of speech information, a pattern of binary gains provides an adequate basis for speech perception....

  16. Issues and design concepts for high-activity liquid packaging

    The tank waste pretreatment process involves the separation of low-level and high-level constituents. The liquid high-level defense production waste will be vitrified into thousands of glass logs at the US DOE sites and then transported to a high-level repository for final disposal. Pretreatment and vitrification technology will need to be developed and tested to assess cost-effectiveness. The appropriate pretreatment strategy for complex high-activity liquid will depend on proving a competent process. As technology development matures, actual liquid will be substituted for simulants, and pilot scale plants will replace laboratory scale process demonstrations. Development of this strategy depends on tank waste sample analyses and a high-activity liquid supply for process testing. However, high-activity liquid transportation beyond DOE site boundaries is limited to Type B quantities in volumes less than 50 mL; no licensed packaging exists for greater than 50 mL quantities. The following paper summarizes the need for a high-activity liquid packaging, and identifies the agencies effecting packaging design and transportation. The high-activity liquid packaging concept retrofits licensed spent fuel casks by replacing the spent fuel basket with a sturdy containment vessel appropriate for the chemical nature of the liquid. A Nuclear Packaging (Pacific Nuclear's NuPat trademark 125-B) spent fuel cask was hypothetically retrofitted with a containment vessel filled with liquid source term, the radionuclide inventory contained in the liquid. The structural, thermal, dose rate, and criticality consequences of retrofitting the cask body were evaluated based on data in the 125-B Cask Safety Analysis Report for Packaging. In addition, future packaging development work is discussed

  17. Optical gain by a simple photoisomerization process.

    Gallego-Gómez, Francisco; del Monte, Francisco; Meerholz, Klaus

    2008-06-01

    Organic holographic materials are pursued as versatile and cheap data-storage materials. It is generally assumed that under steady-state conditions, only photorefractive holographic media exhibit a non-local response to a light-intensity pattern, which results in an asymmetric two-beam coupling or 'gain', where intensity is transferred from one beam to the other as a measure of writing efficiency. Here, we demonstrate non-local holographic recording in a non-photorefractive material. We demonstrate that reversible photoisomerization gratings recorded in a non-photorefractive azo-based material exhibit large optical gain coefficients beyond 1,000 cm(-1), even for polarization gratings. The grating characteristics differ markedly from classical photorefractive features, but can be modelled by considering the influence of the Poynting vector on the photoisomerization. The external control of the Poynting vector enables manipulation of the gain coefficient, including its sign (the direction of energy exchange), a novel phenomenon we refer to as 'gain steering'. A very high sensitivity of about 100 cm(2) J(-1) was achieved. This high sensitivity, combined with a high spatial resolution, suggests a great technical advantage for applications in image processing and phase conjugation. PMID:18454152

  18. Gain control mechanisms in the nociceptive system.

    Treede, Rolf-Detlef

    2016-06-01

    The "gate control theory of pain" of 1965 became famous for integrating clinical observations and the understanding of spinal dorsal horn circuitry at that time into a testable model. Although it became rapidly clear that spinal circuitry is much more complex than that proposed by Melzack and Wall, their prediction of the clinical efficacy of transcutaneous electrical nerve stimulation and spinal cord stimulation has left an important clinical legacy also 50 years later. In the meantime, it has been recognized that the sensitivity of the nociceptive system can be decreased or increased and that this "gain control" can occur at peripheral, spinal, and supraspinal levels. The resulting changes in pain sensitivity can be rapidly reversible or persistent, highly localized or widespread. Profiling of spatio-temporal characteristics of altered pain sensitivity (evoked pain to mechanical and/or heat stimuli) allows implications on the mechanisms likely active in a given patient, including peripheral or central sensitization, intraspinal or descending inhibition. This hypothesis generation in the diagnostic process is an essential step towards a mechanism-based treatment of pain. The challenge now is to generate the rational basis of multimodal pain therapy algorithms by including profile-based stratification of patients into studies on efficacy of pharmacological and nonpharmacological treatment modalities. This review outlines the current evidence base for this approach. PMID:26817644

  19. Active Snubber Circuit for High Power Inverter Leg

    Rasmussen, Tonny Wederberg; Johansen, Morten Holst

    2009-01-01

    Abstract— High power converters in the conventional 6 pulse configuration with 6 switching elements IGBTs (Insulated Gate Bipolar Transistor) are pushed to the limit of power. Especially the switching loss is high. This reduces the switching frequency due to cooling problems. Passive snubber...... circuits have been introduced to reduce the loss even though some of the loss is removed from the IGBT to the snubber resistance. This paper takes also the next step to introduce the active Undeland snubber which in principle is lossless. The paper describes this solution together with some simulations...... indicating that the switching loss is reduced. Comparison between hard switched, passive and active snubber is done....

  20. Highly Active Rutile TiO2 for Photocatalysis

    Junping Yan; Zilong Tang; Zhongtai Zhang; Zhigang Zhou

    2006-01-01

    Nanocrystalline titania was prepared by the homogeneous-precipitation method at temperature lower than 120℃.The properties of powders were identified by XRD, TEM and diffuse reflection spectra. The results showed that rutile titania formed at 70℃ without calcination in air. Nanometer rutile TiO2 had good crystalline and small particle size. The formation mechanism of rutile was also discussed. The photocatalytic activity of the prepared particles was tested for the degradation of methyl orange. The photocatalytic activity of rutile TiO2 was higher than those obtained from Degussa P-25 TiO2. The reasons for high photocatalytic activity of rutile were discussed.