WorldWideScience

Sample records for activated high gain

  1. High power VCSEL device with periodic gain active region

    Science.gov (United States)

    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. New high-gain detectors for active imaging

    Science.gov (United States)

    Pistone, Frederic; Tribolet, P.; Lefoul, X.; Zecri, M.; Courtas, S.; Jenouvrier, P.; Rothman, Johan

    2009-05-01

    New applications require high sensitivity infrared (IR) sensors in order to detect very low incident fluxes. Laser gated imaging has, in particular, additional specific needs. IR sensors for this type of application are synchronized with eye-safe lasers, and have to detect a weak signal backscattered from the target on the order of 10 photons per pulse. They also have to be able to operate with a very short integration time, typically one hundred nanoseconds, to gate the backscattered signal around the target. In partnership with Sofradir, CEA/LETI, France) has developed high quality HgCdTe avalanche photodiodes satisfying these requirements. In parallel, specific studies have been carried out at the Read-Out Circuit level to develop optimized architectures. Thanks to these advances, a new Integrated Dewar Detector Cooler Assembly has been developed. This new product is the first step in a road-map to address low flux infrared sensors in the next few years.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Science.gov (United States)

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

    Science.gov (United States)

    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.

  6. Review of High Gain FELs

    International Nuclear Information System (INIS)

    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

  7. Sudden gains in behavioural activation for depression.

    Science.gov (United States)

    Masterson, Ciara; Ekers, David; Gilbody, Simon; Richards, David; Toner-Clewes, Benjamin; McMillan, Dean

    2014-09-01

    Sudden gains have been linked to improved outcomes in cognitive behaviour therapy for depression. The relationship between sudden gains and outcome is less clear in other treatment modalities, including interpersonal psychotherapy and supportive expressive therapy, which may indicate different mechanisms of change between treatment modalities. The current study examined sudden gains in adults meeting diagnostic criteria for depression (N = 40) offered up to 12 sessions of behavioural activation treatment. Sudden gains were found in 42.5% of the sample. Sudden gains occurred early (median pre-gain session 2) and were related to outcome: those who experienced a sudden gain had significantly lower post-treatment scores on the PHQ-9. Furthermore, the proportion meeting the reliable and clinically significant change criteria at end of treatment was higher in the sudden gain group. These findings highlight the importance of understanding the mechanisms by which sudden gains relate to therapy outcome in behavioural activation.

  8. High current gain transistor laser

    Science.gov (United States)

    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.

  9. Active Microwave Metamaterials Incorporating Ideal Gain Devices

    Directory of Open Access Journals (Sweden)

    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.

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

    KAUST Repository

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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. High-Gain High-Field Fusion Plasma

    Science.gov (United States)

    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.

  13. PBG Based High Gain Microstrip Stacked Antenna

    Directory of Open Access Journals (Sweden)

    Babulal Chaudhary

    2013-03-01

    Full Text Available In this paper, authors have proposed the analysis of a rectangular stacked patch antenna operates at the frequency of 2.4 GHz with a photonic band-gap structure (PBG and compared its performances with a conventional patch antenna. Due to the presence of the PBG structure in the dielectric substrate, proposed antenna shows a significant reduction in surface wave levels than a conventional patch antenna. As a result, the gain of the proposed antenna is found to be improved by 3.2 dB

  14. Extended High-Gain Observer for Mars Entry Guidance

    Directory of Open Access Journals (Sweden)

    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.

  15. A Unified Approach to High-Gain Adaptive Controllers

    Directory of Open Access Journals (Sweden)

    Ian A. Gravagne

    2009-01-01

    Full Text Available It has been known for some time that proportional output feedback will stabilize MIMO, minimum-phase, linear time-invariant systems if the feedback gain is sufficiently large. High-gain adaptive controllers achieve stability by automatically driving up the feedback gain monotonically. More recently, it was demonstrated that sample-and-hold implementations of the high-gain adaptive controller also require adaptation of the sampling rate. In this paper, we use recent advances in the mathematical field of dynamic equations on time scales to unify and generalize the discrete and continuous versions of the high-gain adaptive controller. We prove the stability of high-gain adaptive controllers on a wide class of time scales.

  16. High gain durable anti-reflective coating

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Prismatic louver active façades for natural illumination and thermal energy gain in high-rise and commercial buildings

    Science.gov (United States)

    Vlachokostas, A.; Volkmann, C.; Madamopoulos, N.

    2013-06-01

    High-rise and commercial buildings in urban centers present a great challenge in terms of their energy consumption. Due to maximization of rentable square footage, the preferred urban façade system over the past 50 years has been the "curtain wall", only a few inches thick and comprised of modular steel or aluminum framing and predominant glass infills. The perceived Achilles heel of these modern glass façade systems is their thermal inefficiency: They are inadequate thermal barriers and exhibit excessive solar gain. The excessive solar gain has a negative impact on lighting and cooling loads of the entire building. This negative impact will be further exacerbated with rising energy costs. However, rather than view the glass façade's uncontrolled solar gain merely as a weakness contributing to higher energy consumption, the condition could indeed be considered as related to an energy solution. These glass façades can be retrofitted to operate as a provider of daylight and energy for the rest of the building, taking advantage of the overexposure to the sun. With today's technology, the sun's abundant renewable energy can be the driving force for the energy transition of these building envelopes. Illumination, thermal energy, and electricity production can be directly supplied from the sun, and when correctly and efficiently managed, they can lead to a significantly less energy-intensive building stock. We propose a multi-purpose, prismatic, louver-based façade to perform both daylight and thermal energy harvesting with a goal of offering a better daylight environment for the occupants, and reduce the energy consumption and carbon footprint of the building. While decentralized air-conditioning units are commonly accepted as façade "plug-ins", such decentralization could be utilized with more benefits by passively managing the interior space conditions, without using any extra power. Just as living organisms respond and adapt to the environmental changes in

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

    DEFF Research Database (Denmark)

    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....

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

    DEFF Research Database (Denmark)

    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....

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

    Science.gov (United States)

    Li, Ma; Zhigong, Wang; Jian, Xu; Yiqiang, Wu; Junliang, Wang; Mi, Tian; Jianping, Chen

    2015-02-01

    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.

  1. A Novel High Gain DC-DC Step up Converter

    Directory of Open Access Journals (Sweden)

    M. Al Mamun

    2016-07-01

    Full Text Available High gain dc-dc converters are widely used to maximize the energy harvest for renewable energy systems, for example, photovoltaic systems and fuel cell. Conventional boost converters usually operates at extreme duty cycle to obtain high voltage gain. Operation at extreme duty cycle leads to reverse recovery problem at the switches, high conduction loss, electromagnetic interference etc. This paper proposes a very high gain dc-dc step up converter operating at very low duty cycle (i.e. duty cycle <0.5. The additional advantage of the proposed converter is that a single control signal is used for the switches which reduces the operation complexity. The steady-state theoretical analysis described in this paper is finally verified by simulation results

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    Passive photonic crystals have been shown to exhibit a multitude of interesting phenomena, including slow-light propagation in line-defect waveguides. It was suggested that by incorporating an active material in the waveguide, slow light could be used to enhance the effective gain of the material......, 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...... to those realized in state-of-the-art semiconductor optical amplifiers should be attainable in compact photonic integrated amplifiers...

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

    International Nuclear Information System (INIS)

    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

  4. SOFT-SWITCHED HIGH STEP-UP DC-DC CONVERTER WITH HIGH VOLTAGE GAIN

    Directory of Open Access Journals (Sweden)

    J.C. PAUL IMMANUEL

    2013-04-01

    Full Text Available This paper presents a new design of soft switched high step-up dc-dc converter with high voltage gain which is suitable for high power applications such as Uninterruptible Power System (UPS, Photo Voltaic system and hybrid electric vehicles. The emergence of this front-end converter is to improve the shape of active input current given to the system. This converter proposes Soft-Switching technique to achieve ZVS turn on of active switches and ZCS turn off of diodes using Lr - Cr resonance in the auxiliary circuit. Therefore reduces the switching losses. Comparatively the voltage conversion ratio of this converter is higher when compared with the ordinary boost converter. Hence the voltage gain of this converter is also higher. A simulation platform is created using MATLAB which illustrates the ZVS and ZCS operation of the switches and diodes. Open loop and closed loop controlled converter systems are modelled and simulated.

  5. Best Practices for Achieving High, Rapid Reading Gains

    Science.gov (United States)

    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…

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

    International Nuclear Information System (INIS)

    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)

  7. A High Gain Omnidirectional Antenna Using Negative Permeability Metamaterial

    Directory of Open Access Journals (Sweden)

    Hangfei Tang

    2013-01-01

    Full Text Available A high gain omnidirectional antenna with low profile is proposed and is investigated numerically and experimentally. Based on the conventional center-fed circular epsilon-negative (ENG zeroth-order resonator (ZOR antenna, dendritic structure negative permeability metamaterial (NPM is used as the substrate to enhance the gain of the omnidirectional antenna. The experimental results show that the gain of a center-fed circular ENG ZOR antenna with NPM substrate is enhanced about 2.2 dB, and the efficiency is enhanced about 38%, in the whole broad operating bandwidth as compared to that of the antenna without NPM substrate, which can be used to improve the reliability of wireless communications.

  8. A Scalable Deployable High Gain Antenna - DaHGR

    OpenAIRE

    Kelly, P. Keith

    2016-01-01

    MMA Design (MMA) has invented and is developing a revolutionary deployable antenna solution providing extremely high areal compaction for future microsatellite missions. Our solution combines the positive attributes of currently fielded antenna systems and will enable performance for microsatellites consistent with today’s large space craft payloads. The MMA patented and patent pending Deployable High Gain Reflectarray (DaHGR) antenna has both a wideband and a narrower band configuration. The...

  9. STARS A Two Stage High Gain Harmonic Generation FEL Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    M. Abo-Bakr; W. Anders; J. Bahrdt; P. Budz; K.B. Buerkmann-Gehrlein; O. Dressler; H.A. Duerr; V. Duerr; W. Eberhardt; S. Eisebitt; J. Feikes; R. Follath; A. Gaupp; R. Goergen; K. Goldammer; S.C. Hessler; K. Holldack; E. Jaeschke; Thorsten Kamps; S. Klauke; J. Knobloch; O. Kugeler; B.C. Kuske; P. Kuske; A. Meseck; R. Mitzner; R. Mueller; M. Neeb; A. Neumann; K. Ott; D. Pfluckhahn; T. Quast; M. Scheer; Th. Schroeter; M. Schuster; F. Senf; G. Wuestefeld; D. Kramer; Frank Marhauser

    2007-08-01

    BESSY is proposing a demonstration facility, called STARS, for a two-stage high-gain harmonic generation free electron laser (HGHG FEL). STARS is planned for lasing in the wavelength range 40 to 70 nm, requiring a beam energy of 325 MeV. The facility consists of a normal conducting gun, three superconducting TESLA-type acceleration modules modified for CW operation, a single stage bunch compressor and finally a two-stage HGHG cascaded FEL. This paper describes the faciliy layout and the rationale behind the operation parameters.

  10. 20 CFR 416.972 - What we mean by substantial gainful activity.

    Science.gov (United States)

    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...

  11. 20 CFR 404.1572 - What we mean by substantial gainful activity.

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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.

  13. Fast ignition integrated experiments and high-gain point design

    Energy Technology Data Exchange (ETDEWEB)

    Shiraga, H. [Osaka Univ., Osaka (Japan); Nagatomo, H. [Osaka Univ., Osaka (Japan); Theobald, W. [Univ. of Rochester, Rochester, NY (United States); Solodov, A. A. [Univ. of Rochester, Rochester, NY (United States); Tabak, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-04-17

    Here, integrated fast ignition experiments were performed at ILE, Osaka, and LLE, Rochester, in which a nanosecond driver laser implodes a deuterated plastic shell in front of the tip of a hollow metal cone and an intense ultrashort-pulse laser is injected through the cone to heat the compressed plasma. Based on the initial successful results of fast electron heating of cone-in-shell targets, large-energy short-pulse laser beam lines were constructed and became operational: OMEGA-EP at Rochester and LFEX at Osaka. Neutron enhancement due to heating with a ~kJ short-pulse laser has been demonstrated in the integrated experiments at Osaka and Rochester. The neutron yields are being analyzed by comparing the experimental results with simulations. Details of the fast electron beam transport and the electron energy deposition in the imploded fuel plasma are complicated and further studies are imperative. The hydrodynamics of the implosion was studied including the interaction of the imploded core plasma with the cone tip. Theory and simulation studies are presented on the hydrodynamics of a high-gain target for a fast ignition point design.

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

  16. 26 CFR 7.105-2 - Substantial gainful activity.

    Science.gov (United States)

    2010-04-01

    ....105-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) TEMPORARY INCOME TAX REGULATIONS UNDER THE TAX REFORM ACT OF 1976 § 7.105-2 Substantial gainful... minimum wage prescribed by section 6(a)(1) of the Fair Labor Standards Act of 1938, as amended, 29...

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

    Science.gov (United States)

    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

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

    DEFF Research Database (Denmark)

    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...... 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...... to the maximal EMG activity during maximal voluntary contractions, and a p value muscles reached sufficiently high levels of activity during the coordination exercises for strength gain (>60% of maximal EMG activity). Type of exercise played a significant role...

  19. Telescope considered as a very high gain antenna

    Science.gov (United States)

    Detaille, Michel; Houmault, Patrice

    1990-07-01

    A design concept for an optical-antenna telescope to be used in intersatellite communication (in the framework of the ESA SILEX project) is presented. The main technical requirements for a SILEX transmit-receive antennna telescope are reviewed, and a Cassegrain configuration based on a parabolic primary mirror, a hyperbolic secondary mirror, and a five-lense collimator (with baffles to limit stray light) is shown in diagrams and discussed in detail, with particular attention to local angular distortion and transmission-antenna gain. Results from tests on a breadboard version are presented in tables and graphs, including transmission of 92.6 percent at 820 nm, rms wavefront error less than lambda/28, optical gain 114.47 dB, backscattered energy 1.7 x 10 to the -6th at 838 nm, and stray-light intensity slightly above specification at sun aspect angles less than 4.5 deg.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  2. Spontaneous physical activity protects against fat mass gain

    OpenAIRE

    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...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  5. High gain 1.3-μm GaInNAs SOA with fast gain dynamics and enhanced temperature stability

    Science.gov (United States)

    Fitsios, D.; Giannoulis, G.; Iliadis, N.; Korpijärvi, V.-M.; Viheriälä, J.; Laakso, A.; Dris, S.; Spyropoulou, M.; Avramopoulos, H.; Kanellos, G. T.; Pleros, N.; Guina, M.

    2014-03-01

    Semiconductor optical amplifiers (SOAs) are a well-established solution of optical access networks. They could prove an enabling technology for DataCom by offering extended range of active optical functionalities. However, in such costand energy-critical applications, high-integration densities increase the operational temperatures and require powerhungry external cooling. Taking a step further towards improving the cost and energy effectiveness of active optical components, we report on the development of a GaInNAs/GaAs (dilute nitride) SOA operating at 1.3μm that exhibits a gain value of 28 dB and combined with excellent temperature stability owing to the large conduction band offset between GaInNAs quantum well and GaAs barrier. Moreover, the characterization results reveal almost no gain variation around the 1320 nm region for a temperature range from 20° to 50° C. The gain recovery time attained values as short as 100 ps, allowing implementation of various signal processing functionalities at 10 Gb/s. The combined parameters are very attractive for application in photonic integrated circuits requiring uncooled operation and thus minimizing power consumption. Moreover, as a result of the insensitivity to heating issues, a higher number of active elements can be integrated on chip-scale circuitry, allowing for higher integration densities and more complex optical on-chip functions. Such component could prove essential for next generation DataCom networks.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. High Gain Compact Strip and Slot UWB Sinuous Antennas

    Directory of Open Access Journals (Sweden)

    Elson Agastra

    2012-01-01

    Full Text Available Three ground-backed compact strip-and slot-sinuous antennas are analyzed. Proposed configuration allows for a single lobe, polarization-versatile, high efficiency, and ultrawide band antenna not needing a cumbersome lossy back cavity typical of conventional single-lobe sinuous antennas. Simulations show attained performances as well as tuning possibilities.

  8. 20 CFR 220.29 - Work that is considered substantial gainful activity.

    Science.gov (United States)

    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...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Avalanche effect and gain saturation in high harmonic generation

    CERN Document Server

    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...

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

    International Nuclear Information System (INIS)

    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

  12. Design and Analysis of High Gain Diode Pre-Distortion Linearizer for TWTA

    Directory of Open Access Journals (Sweden)

    Anuraag Misra

    2014-11-01

    Full Text Available This paper presents the design and analysis of a hi gh gain, broadband Schottky and PIN diode based RF pre-distortion linearizer for TWTA. The circuit is using ABCD matrix approach. The simulation is performed using Agilent ADS software. We have propo sed a new linearizer circuit which can achieve a high gain compared to existing linearizer designs.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    CERN Document Server

    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).

  15. New Primary-Parallel Boost Converter for High-Power High-Gain Applications

    DEFF Research Database (Denmark)

    Nymand, Morten; Andersen, Michael A. E.

    2009-01-01

    Abstract—A new simple and low cost method for paralleling multiple power stages in high-power high-gain isolated full-bridge boost converters is presented. A small current balancing transformer and serial connection of transformer secondary windings provides ideal current sharing between paralleled...... and manufacturing. Extension of the principle to other isolated boost converter topologies are demonstrated as well as extension to higher numbers of parallel operated power stages. Test results from a 3 kW experimental prototype converter are presented, verifying converter operation and demonstrating current...... sharing capability. Very high converter efficiency is achieved. Worst case efficiency at minimum input voltage and maximum power is 96.9 %. Maximum efficiency is 98 %....

  16. Gain and loss enhancement in active and passive particulate composite materials

    CERN Document Server

    Mackay, Tom G

    2015-01-01

    Two active dielectric materials may be blended together to realize a homogenized composite material (HCM) which exhibits more gain than either component material. Likewise, two dissipative dielectric materials may be blended together to realize an HCM which exhibits more loss than either component material. Sufficient conditions for such gain/loss enhancement were established using the Bruggeman homogenization formalism. Gain/loss enhancement arises when (i) the imaginary parts of the relative permittivities of both component materials are similar in magnitude and (ii) the real parts of the relative permittivities of both component materials are dissimilar in magnitude.

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

    International Nuclear Information System (INIS)

    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

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

    Data.gov (United States)

    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...

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

    CERN Document Server

    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).

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

    OpenAIRE

    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...

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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.

  3. High-Gain AlxGa1-xAs/GaAs Transistors For Neural Networks

    Science.gov (United States)

    Kim, Jae-Hoon; Lin, Steven H.

    1991-01-01

    High-gain AlxGa1-xAs/GaAs npn double heterojunction bipolar transistors developed for use as phototransistors in optoelectronic integrated circuits, especially in artificial neural networks. Transistors perform both photodetection and saturating-amplification functions of neurons. Good candidates for such application because structurally compatible with laser diodes and light-emitting diodes, detect light, and provide high current gain needed to compensate for losses in holographic optical elements.

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

    Science.gov (United States)

    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

  5. Polarization-insensitive optical gain characteristics of highly stacked InAs/GaAs quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Kita, Takashi; Suwa, Masaya; Kaizu, Toshiyuki; Harada, Yukihiro [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

    2014-06-21

    The polarized optical gain characteristics of highly stacked InAs/GaAs quantum dots (QDs) with a thin spacer layer fabricated on an n{sup +}-GaAs (001) substrate were studied in the sub-threshold gain region. Using a 4.0-nm-thick spacer layer, we realized an electronically coupled QD superlattice structure along the stacking direction, which enabled the enhancement of the optical gain of the [001] transverse-magnetic (TM) polarization component. We systematically studied the polarized electroluminescence properties of laser devices containing 30 and 40 stacked InAs/GaAs QDs. The net modal gain was analyzed using the Hakki-Paoli method. Owing to the in-plane shape anisotropy of QDs, the polarization sensitivity of the gain depends on the waveguide direction. The gain showing polarization isotropy between the TM and transverse-electric polarization components is high for the [110] waveguide structure, which occurs for higher amounts of stacked QDs. Conversely, the isotropy of the [−110] waveguide is easily achieved even if the stacking is relatively low, although the gain is small.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  8. DEMONSTRATION OF 3D EFFECTS WITH HIGH GAIN AND EFFICIENCY IN A UV FEL OSCILLATOR

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Benson; George Biallas; Keith Blackburn; James Boyce; Donald Bullard; James Coleman; Cody Dickover; David Douglas; Forrest Ellingsworth; Pavel Evtushenko; Carlos Hernandez-Garcia; Christopher Gould; Joseph Gubeli; David Hardy; Kevin Jordan; John Klopf; James Kortze; Robert Legg; Matthew Marchlik; Steven Moore; George Neil; Thomas Powers; Daniel Sexton; Michelle D. Shinn; Christopher Tennant; Richard Walker; Anne Watson; Gwyn Williams; Frederick Wilson; Shukui Zhang

    2011-03-01

    We report on the performance of a high gain UV FEL oscillator operating on an energy recovery linac at Jefferson Lab. The high brightness of the electron beam leads to both gain and efficiency that cannot be reconciled with a one-dimensional model. Three-dimensional simulations do predict the performance with reasonable precision. Gain in excess of 100% per pass and an efficiency close to 1/2NW, where NW is the number of wiggler periods, is seen. The laser mirror tuning curves currently permit operation in the wavelength range of 438 to 362 nm. Another mirror set allows operation at longer wavelengths in the red with even higher gain and efficiency.

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

    KAUST Repository

    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.

  10. High gain GaAs switches for impulse sources: Measurement of the speed of current filaments

    Energy Technology Data Exchange (ETDEWEB)

    Loubriel, G.M.; Zutavern, F.J.; O`Maliey, M.W.; Gallegos, R.R.; Helgeson, W.D.; Hjalmarson, H.P.; Baca, A.G.; Plut, T.A.

    1994-07-01

    A high peak power impulse pulser that is controlled with high gain, optically triggered GaAs Photoconductive Semiconductor Switches (PCSS) has been constructed and tested. The system has a short 50 ohm line that is charged to 100 kV and discharged through the switch when the switch is triggered with as little as 90 nJ of laser energy. The authors have demonstrated that the GaAs switches can be used to produce either a monocycle or a monopulse with a period of total duration of about 3 ns. For the monopulse, the voltage switched was above 100 kV, producing a peak power of about 48 MW to the 30 ohm load at a burst repetition rate of 1 kHz. The laser that is used is a small laser diode array whose output is delivered through a fiber to the switch. The current in the system has rise times of 430 ps and a pulse width of 1.4 ns when two laser diode arrays are used to trigger the switch. The small trigger energy and switch jitter are due to a high gain switching mechanism in GaAs. This experiment also shows a relationship between the rise time of the voltage across the switch and the required trigger energy and switch jitter. The time evolution of the current filaments in an optically triggered, high gain GaAs switch was studied by recording the infrared photoluminescence from the filaments. When the system is triggered with two laser diode arrays that are activated within 1 ns of each other, two current filaments are observed. By delaying one laser with respect to the other, the evolution of the filament was recorded in a time resolved fashion. The filament that is triggered first crosses the switch, the voltage drops and the other filament ceases to grow. By varying the delay between the trigger lasers, the tip velocity is measured to be up to 5.9 {+-} 1 {times} 10{sup 9} cm/s.

  11. Measurements of high gain and noise fluctuations in a SASE free electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, M.; Anderson, S.; Bishofberger, K.; Frigola, P.; Murokh, A.; Osmanov, N.; Pellegrini, C.; Reiche, S.; Rosenzweig, J.; Travish, G.; Tremaine, A.; Varfolomeev, A. [UCLA Department of Physics and Astronomy, Los Angeles, California (United States)

    1997-06-01

    We report measurements of large gain for a single pass Free Electron Laser operating in Self Amplified Spontaneous Emission (SASE) at 16 {mu}m starting from noise. We also report the first observation and analysis of intensity fluctuations of the SASE radiation intensity in the high gain regime. The results are compared with theoretical predictions and simulations. {copyright} {ital 1997 American Institute of Physics.}

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

    OpenAIRE

    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.

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

    Science.gov (United States)

    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

  14. Shock-Ignited High Gain/Yield Targets for the National Ignition Facility

    Science.gov (United States)

    Perkins, L. J.; Lafortune, K. N.; Bedrosiian, P.; Tabak, M.; Miles, A.; Dixit, S.; Betti, R.; Anderson, K.; Zhou, C.

    2006-10-01

    Shock-ignition, a new concept for ICF ignition [C.Zhou, R.Betti Bull APS, v50, 2005], is being studied as a future option for efficiently achieving high gains in large laser facilities such as NIF. Accordingly, this offers the potential for testing: (1)High yield (up to 200MJ), reactor-relevant targets for inertial fusion energy (2)High fusion yield targets for DOE NNSA stockpile application (3)Targets with appreciable gain at low laser drive energies (gains of 10's at 150kJ) (4)Ignition of simple, non-cryo (room temperature) single shell gas targets at (unity gain). By contrast to conventional hotspot ignition, we separate the assembly and ignition phases by initially imploding a massive cryogenic shell on a low adiabat (alpha 0.7) at low velocity (less than 2e7cm/s) using a direct drive pulse of modest total energy. The assembled fuel is then separately ignited by a strong, spherically convergent shock driven by a high intensity spike at the end of the pulse and timed to reach the center as the main fuel is stagnating and starting to rebound. Like fast ignition, shock ignition can achieve high gains with low drive energy, but has the advantages of requiring only a single laser with less demanding timing and spatial focusing requirements.

  15. 78 FR 74125 - Agency Information Collection Activities; Comment Request; Measuring Educational Gain in the...

    Science.gov (United States)

    2013-12-10

    ... Agency Information Collection Activities; Comment Request; Measuring Educational Gain in the National.... chapter 3501 et seq.), ED is proposing an extension of an existing information collection. DATES... submitted after the comment period will not be accepted. Written requests for information or...

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

    DEFF Research Database (Denmark)

    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....

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    of AMPK in skeletal muscle. IL-18R(-/-) mice display increased weight gain, and ectopic lipid deposition, inflammation and reduced AMPK signaling in skeletal muscle. Treating myotubes or skeletal muscle strips with IL-18 activated AMPK and increased fat oxidation. Moreover, in vivo electroporation of IL...

  18. Alumni networks-an untapped potential to gain and retain highly-skilled workers?

    NARCIS (Netherlands)

    David, Alexandra; Coenen, Frans

    2014-01-01

    In times of increasing skills shortage, regions and particularly non-core regions, need to attract highly-skilled workers. It is better for these regions to (re)-attract highly-skilled workers that gained knowledge and contacts elsewhere and because they once lived in the region for study have alrea

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

    Science.gov (United States)

    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).

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

    International Nuclear Information System (INIS)

    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)

  1. High-gain X-ray free electron laser by beat-wave terahertz undulator

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chao; Hei, DongWei [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi' an City 710024 (China); Institute of Energy, Tsinghua University, Beijing 100084 (China); Pellegrin, Claudio; Tantawi, Sami [SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94309 (United States)

    2013-12-15

    The THz undulator has a higher gain to realize a much brighter X-ray at saturation, compared with the optical undulator under the same undulator strength and beam quality. In order to fill the high-power THz gap and realize the THz undulator, two superimposed laser pulses at normal incidence to the electron-beam moving direction form an equivalent high-field THz undulator by the frequency difference to realize the high-gain X-ray Free electron laser. The pulse front tilt of lateral fed lasers is used to realize the electron-laser synchronic interaction. By PIC simulation, a higher gain and a larger X-ray radiation power by the beat wave THz undulator could be realized, compared with the optical undulator for the same electron beam parameters.

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

    DEFF Research Database (Denmark)

    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...... dilution bias and decreases the precision of the estimate of an association between PA and adiposity. Furthermore, because gains in adiposity often are caused by a small average daily energy imbalance over many years, following individuals for longer periods of time is essential to characterize...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    DEFF Research Database (Denmark)

    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....

  6. High-Directional Wave Propagation in Periodic Gain/Loss Modulated Materials

    CERN Document Server

    Kumar, N; Herrero, R; Loiko, Yu; Staliunas, K

    2012-01-01

    Amplification/attenuation of light waves in artificial materials with a gain/loss modulation on the wavelength scale can be sensitive to the propagation direction. We give a numerical proof of the high anisotropy of the gain/loss in two dimensional periodic structures with square and rhombic lattice symmetry by solving the full set of Maxwell's equations using the finite difference time domain method. Anisotropy of amplification/attenuation leads to the narrowing of the angular spectrum of propagating radiation with wavevectors close to the edges of the first Brillouin Zone. The effect provides a novel and useful method to filter out high spatial harmonics from noisy beams.

  7. Very high-accuracy calibration of radiation pattern and gain of a near-field probe

    DEFF Research Database (Denmark)

    Pivnenko, Sergey; Nielsen, Jeppe Majlund; Breinbjerg, Olav

    2014-01-01

    In this paper, very high-accuracy calibration of the radiation pattern and gain of a near-field probe is described. An open-ended waveguide near-field probe has been used in a recent measurement of the C-band Synthetic Aperture Radar (SAR) Antenna Subsystem for the Sentinel 1 mission of the Europ......In this paper, very high-accuracy calibration of the radiation pattern and gain of a near-field probe is described. An open-ended waveguide near-field probe has been used in a recent measurement of the C-band Synthetic Aperture Radar (SAR) Antenna Subsystem for the Sentinel 1 mission...

  8. Adaptive control of linear multivariable systems with high frequency gain matrix hurwitz

    Institute of Scientific and Technical Information of China (English)

    Ying ZHOU; Yuqiang WU; Shumin FEI

    2005-01-01

    A new adaptive control scheme is proposed for multivariable model reference adaptive control(MRAC) systems based on the nonlinear backstepping approach with vector form.The assumption on a priori knowledge of the high frequency gain matrix in existing results is relaxed and the new required condition for the high frequency gain matrix can be easily checked for certain plants so that the proposed method is widely applicable.This control scheme guarantees the global stability of the closed-loop systems and the tracking error can be arbitrary small.The simulation result for an application example shows the validity of the proposed nonlinear adaptive scheme.

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

    KAUST Repository

    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.

  10. Dynamic properties of a pulse-pumped fiber laser with a short, high-gain cavity

    Science.gov (United States)

    Yang, Chaolin; Guo, Junhong; Wei, Pu; Wan, Hongdan; Xu, Ji; Wang, Jin

    2016-09-01

    We demonstrate a pulsed high-gain all-fiber laser without intracavity modulators, where a short and heavily Erbium-doped fiber is used as the gain medium in a ring cavity. By pulsed-pumping this short high gain cavity and tuning an intracavity variable optical coupler, the laser generates optical pulses with a pulse-width of μs at a repetition rate in the order of kHz down to one-shot operation. Furthermore, dynamic properties of this laser are investigated theoretically based on a traveling-wave-model, in which an adaptive-discrete-grid-finite-difference-method is applied. The simulation results validate the experimental results. The demonstrated pulsed laser is compact, flexible and cost-effective, which will have great potential for applications in all-optical sensing and communication systems.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    DEFF Research Database (Denmark)

    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...

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

    Science.gov (United States)

    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

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

    NARCIS (Netherlands)

    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.

  17. 75 FR 61228 - Board Meeting: Technical Lessons Gained From High-Level Nuclear Waste Disposal Efforts

    Science.gov (United States)

    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 of 1987, the U.S. Nuclear Waste Technical...

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

    KAUST Repository

    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.

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

    DEFF Research Database (Denmark)

    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...

  20. Prior exercise training blunts short-term high-fat diet-induced weight gain.

    Science.gov (United States)

    Snook, Laelie A; MacPherson, Rebecca E K; Monaco, Cynthia M F; Frendo-Cumbo, Scott; Castellani, Laura; Peppler, Willem T; Anderson, Zachary G; Buzelle, Samyra L; LeBlanc, Paul J; Holloway, Graham P; Wright, David C

    2016-08-01

    High-fat diets rapidly cause weight gain and glucose intolerance. We sought to determine whether these changes could be mitigated with prior exercise training. Male C57BL/6J mice were exercise-trained by treadmill running (1 h/day, 5 days/wk) for 4 wk. Twenty-four hours after the final bout of exercise, mice were provided with a high-fat diet (HFD; 60% kcal from lard) for 4 days, with no further exercise. In mice fed the HFD prior to exercise training, the results were blunted weight gain, reduced fat mass, and a slight attenuation in glucose intolerance that was mirrored by greater insulin-induced Akt phosphorylation in skeletal muscle compared with sedentary mice fed the HFD. When ad libitum-fed sedentary mice were compared with sedentary high-fat fed mice that were calorie restricted (-30%) to match the weight gain of the previously trained high-fat fed mice, the same attenuated impairments in glucose tolerance were found. Blunted weight gain was associated with a greater capacity to increase energy expenditure in trained compared with sedentary mice when challenged with a HFD. Although mitochondrial enzymes in white adipose tissue and UCP-1 protein content in brown adipose tissue were increased in previously exercised compared with sedentary mice fed a HFD, ex vivo mitochondrial respiration was not increased in either tissue. Our data suggest that prior exercise training attenuates high-fat diet-induced weight gain and glucose intolerance and is associated with a greater ability to increase energy expenditure in response to a high-fat diet.

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

    International Nuclear Information System (INIS)

    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.)

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

    Directory of Open Access Journals (Sweden)

    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.

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

    CERN Document Server

    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.

  4. High-precision gas gain and energy transfer measurements in Ar–CO{sub 2} mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Şahin, Özkan, E-mail: osahin@uludag.edu.tr [Department of Physics, Uludağ University, 16059 Bursa (Turkey); Kowalski, Tadeusz Z. [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Kraków (Poland); Veenhof, Rob [Department of Physics, Uludağ University, 16059 Bursa (Turkey); RD51 collaboration, CERN, Genève (Switzerland)

    2014-12-21

    Ar–CO{sub 2} is a Penning mixture since a fraction of the energy stored in Ar 3p{sup 5}3d and higher excited states can be transferred to ionize CO{sub 2} molecules. In the present work, concentration and pressure dependence of Penning transfer rate and photon feedback parameter in Ar–CO{sub 2} mixtures have been investigated with recent systematic high-precision gas gain measurements which cover the range 1–50% CO{sub 2} at 400, 800, 1200, 1800 hPa and gas gain from 1 to 5×10{sup 5}.

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

    Directory of Open Access Journals (Sweden)

    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.

  6. High gain GaAs photoconductive semiconductor switches: Measurement of filament velocity and reduced trigger energy

    Energy Technology Data Exchange (ETDEWEB)

    Loubriel, G.M.; Zutavern, F.J.; O`Malley, M.W.; Helgeson, W.D.

    1994-11-01

    The time evolution of the current filaments in an optically triggered, high gain GaAs switch was studied by recording the infrared photoluminescence from the filaments. When the switch is triggered with two laser diode arrays (through a fiber optic) that are activated within 1 ns of each other, two current filaments are observed, each one emanating from the point of illumination. By delaying one laser with respect to the other, the evolution of the filament was recorded in a time resolved fashion. The first filament that is triggered crosses the switch, the voltage drops and the other filament ceases to grow. By varying the delay between the trigger lasers, the tip velocity is measured to be up to 5.9 {plus_minus} 1 {times} 10{sup 9} cm/s. This speed is 600 times larger than the peak drift velocity of carriers in GaAs. This observation supports switching models that rely on carrier generation at the tip of the filament. The filaments speed up as they cross the switch: for one voltage range initial speeds were 0.7 {plus_minus} 1 {times} 10{sup 9} cm/s and final speeds (the last 100 ps of motion) exceed 5.5 {plus_minus} 1 {times} 10{sup 9} cm/s. This experiment also shows a relationship between the rise time of the voltage across the switch and the required trigger energy and switch jitter.

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

    OpenAIRE

    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...

  8. Impact of gain saturation on the mode instability threshold in high-power fiber amplifiers

    DEFF Research Database (Denmark)

    Hansen, Kristian Rymann; Lægsgaard, Jesper

    2014-01-01

    We present a coupled-mode model of transverse mode instability in high-power fiber amplifiers, which takes the effect of gain saturation into account. The model provides simple semi-analytical formulas for the mode instability threshold, which are valid also for highly saturated amplifiers. The m....... The model is compared to recently published detailed numerical simulations of mode instability, and we find reasonably good agreement with our simplified coupled-mode model. (C) 2014 Optical Society of America...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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

  11. A low power high gain UWB LNA in 0.18-μm CMOS

    Institute of Scientific and Technical Information of China (English)

    Cai Li; Fu Zhongqian; Huang Lu

    2009-01-01

    A low power high gain differential UWB low noise amplifier (LNA) operating at 3-5 GHz is presented.A common gate input stage is used for wideband input matching; capacitor cross coupling (CCC) and current reuse techniques are combined to achieve high gain under low power consumption. The prototypes fabricated in 0.18-μm CMOS achieve a peak power gain of 17.5 dB with a -3 dB bandwidth of 2.8-5 GHz, a measured minimum noise figure (NF) of 3.35 dB and -12.6 dBm input-referred compression point at 5 GHz, while drawing 4.4 mA from a 1.8 V supply. The peak power gain is 14 dB under a 4.5 mW power consumption (3 mA from a 1.5 V supply). The proposed differential LNA occupies an area of 1.01 mm~2 including test pads.

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

    DEFF Research Database (Denmark)

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

    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...... 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...

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

    OpenAIRE

    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...

  14. Excess Folic Acid Increases Lipid Storage, Weight Gain, and Adipose Tissue Inflammation in High Fat Diet-Fed Rats

    Directory of Open Access Journals (Sweden)

    Karen B. Kelly

    2016-09-01

    Full Text Available Folic acid intake has increased to high levels in many countries, raising concerns about possible adverse effects, including disturbances to energy and lipid metabolism. Our aim was to investigate the effects of excess folic acid (EFA intake compared to adequate folic acid (AFA intake on metabolic health in a rodent model. We conducted these investigations in the setting of either a 15% energy low fat (LF diet or 60% energy high fat (HF diet. There was no difference in weight gain, fat mass, or glucose tolerance in EFA-fed rats compared to AFA-fed rats when they were fed a LF diet. However, rats fed EFA in combination with a HF diet had significantly greater weight gain and fat mass compared to rats fed AFA (p < 0.05. Gene expression analysis showed increased mRNA levels of peroxisome proliferator-activated receptor γ (PPARγ and some of its target genes in adipose tissue of high fat-excess folic acid (HF-EFA fed rats. Inflammation was increased in HF-EFA fed rats, associated with impaired glucose tolerance compared to high fat-adequate folic acid (HF-AFA fed rats (p < 0.05. In addition, folic acid induced PPARγ expression and triglyceride accumulation in 3T3-L1 cells. Our results suggest that excess folic acid may exacerbate weight gain, fat accumulation, and inflammation caused by consumption of a HF diet.

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

    International Nuclear Information System (INIS)

    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)

  16. High-energy electron induced gain degradation in bipolar junction transistors

    Energy Technology Data Exchange (ETDEWEB)

    Kulkarni, S.R. [Department of PG Studies in Physics, SBMJC, Jayanagar, Bangalore 560 011 (India)]. E-mail: srinivask24@hotmail.com; Ravindra, M. [Components Division, ICG, ISRO Satellite Centre, Airport Road, Bangalore 560 017 (India); Joshi, G.R. [Components Division, ICG, ISRO Satellite Centre, Airport Road, Bangalore 560 017 (India); Damle, R. [Department of Physics, Bangalore University, Bangalore 560 056 (India)]. E-mail: damleraju@yahoo.com

    2006-09-15

    This paper describes the effect of 8 MeV electron beam on the forward current gain of space borne commercial indigenous bipolar junction transistors 2N2219A (npn), 2N3019 (npn) and 2N2905A (pnp). The devices are exposed to 8 MeV electron in the biased condition. The collector characteristics and Gummel plots are obtained as a function of accumulated dose. An excess base current model as well as Messenger-Spratt equation have been used to account for the observed gain degradation. The results indicate that 8 MeV electrons of high dose rate induce gain degradation by increasing the base current as well as decrease in collector current. The current gain degradation appears to be predominantly due to displacement damage in the bulk of the transistor. Off-line measurements of the h {sub FE} of the irradiated transistors indicate that the displacement induced defect and recombination centers do not anneal even at 150 {sup o}C.

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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)

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

    CERN Document Server

    Yu, L H; Ben-Zvi, I; Di Mauro, Louis F; Doyuran, A; Graves, W; Johnson, E; Krinsky, S; Malone, R; Pogorelsky, I V; Skaritka, J; Rakowsky, G; Solomon, L; Wang, X J; Woodle, M; Yakimenko, V; Biedron, S G; Galayda, J N; Gluskin, E; Jagger, J; Sajaev, Vadim; Vasserman, I

    2000-01-01

    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 2x10 sup 7 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 (approx 2 m) through the same wiggler. This means the HGHG signal is 2x10 sup 6 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).

  20. Gain engineering for all-optical microwave and high speed pulse generation in mode-locked fiber lasers

    Science.gov (United States)

    Li, Fangxin; Helmy, Amr S.

    2014-03-01

    Pulsed sources based on approaches that employ only photonic components and no RF components will be discussed in this talk. Several technologies have been explored to generate actively mode-locked sources using electronically driven fiber ring cavities. However, for these sources the pulse repetition rate is usually limited by the bandwidth of the intracavity modulator. Filtering of highly-stable low repetition rate optical combs utilizing cavities such as Fabry-Perot etalons can be used to overcome this limitation. This scheme is not flexible as it requires highly precise control of ultrahigh finesse etalons which limits the repetition rate to the free spectral range of the filter. Pulsed sources based on semiconductor devices offer many advantages, including large gain bandwidth, rapid tunability, long-term stability. In this work we introduce a novel, simple method to generate optical clock with wavelength tunability using two continuous wave (CW) lasers. The lasers are injected into a conventional SOAs-based fiber ring laser. The beating signal generated by these two lasers causes the modulation of the SOA gain saturation inside the cavity. Thus, the SOA provides gain and functions as the modulator as well as the gain medium. When the lasing mode inside the cavity is amplified, it also results in gain-induced four wave mixing. The proposed technique is particularly versatile, overcoming the bandwidth limitation of other techniques, which require RF sources. Moreover, this technique provides the possibility for hybrid integration as it is comprised of semiconductor chips that can be heterogeneously integrated on a Si platform.

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

    OpenAIRE

    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...

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

    International Nuclear Information System (INIS)

    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

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

    OpenAIRE

    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...

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

    OpenAIRE

    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...

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

    OpenAIRE

    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...

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Zhou, Haijun; Yang, Wenhai; Li, Zhixiu; Li, Xuefeng; Zheng, Yaohui

    2014-01-01

    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.

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

    KAUST Repository

    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.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Haijun; Yang, Wenhai; Li, Zhixiu; Li, Xuefeng; Zheng, Yaohui, E-mail: yhzheng@sxu.edu.cn [State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China)

    2014-01-15

    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:YVO{sub 4} 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.

  14. Interpolating gain-scheduled H∞ loop shaping design for high speed ball screw feed drives.

    Science.gov (United States)

    Dong, Liang; Tang, WenCheng; Bao, DaFei

    2015-03-01

    This paper presents a method to design servo controllers for flexible ball screw drives with time-varying dynamics, which are mainly due to the time-varying table position and the workpiece mass. A gain-scheduled H∞ loop shaping controller is designed to achieve high tracking performance against the dynamic variations. H∞ loop shaping design procedure incorporates open loop shaping by a set of compensators to obtain performance/robust stability tradeoffs. The interpolating gain-scheduled controller is obtained by interpolating the state space model of the linear time-invariant (LTI) controllers estimated for fixed values of the scheduling parameters and a linear least squares problem can be solved. The proposed controller has been compared with P/PI with velocity and acceleration feedforward and adaptive backstepping sliding mode control experimentally. The experimental results indicate that the tracking performance has been improved and the robustness for time-varying dynamics has been achieved with the proposed scheme.

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

    Science.gov (United States)

    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

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

    OpenAIRE

    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...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    OpenAIRE

    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...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    DEFF Research Database (Denmark)

    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....

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

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

    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.

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

    OpenAIRE

    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...

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

    Science.gov (United States)

    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

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

    CERN Document Server

    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.

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

    Science.gov (United States)

    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.

  11. 110-GHz High-gain Flip-chip InP HEMT Amplifier with Resin Encapsulation on an Organic Substrate

    OpenAIRE

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Science.gov (United States)

    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.

  14. Design of a novel mixer with high gain and linearity improvement for DRM/DAB applications

    Institute of Scientific and Technical Information of China (English)

    Wu Yiqiang; Wang Zhigong; Xu Jian; Wang Jian; Zhang Ouli; Tang Lu

    2013-01-01

    This paper focuses on a new design of a down-conversion mixer for a low-IF wideband receiver.Based on the folded structure and differential multiple gated transistor (DMGTR) technique,a novel quadrature mixer with a high conversion gain,a moderate linearity,and a moderate NF is proposed.The mixer is designed and implemented in a 0.18-μm CMOS process,and can operate in a frequency range from 150 kHz to 1.5 GHz.The circuit performance is confirmed by both simulation and measurement results.The measurement results exhibit a peak conversion gain of 13.35 dB,a high third order input referred intercept point of 14.85 dBm,and a moderate single side band noise figure of 10.67 dB.Moreover,the whole quadrature mixer core occupies a compact die area of 0.122 mm2.It consumes a current of 3.96 mA (excluding the output buffers) under a single supply voltage of 1.8V.

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

    Science.gov (United States)

    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.

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

    CERN Document Server

    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.

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

    Science.gov (United States)

    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

  18. Current gain of 4H SiC high-voltage BJTs at reduced temperatures

    Science.gov (United States)

    Ivanov, P. A.; Levinshtein, M. E.; Palmour, J. W.; Agarwal, A. K.; Krishnaswami, S.

    2007-06-01

    The dependences of the common-emitter current gain β on the collector current IC have been measured at reduced temperatures in 3 kV 4H-SiC epitaxial-emitter npn bipolar junction transistors with implanted p+ base contact and base-emitter distances Lbe ranging from 3 to 15 µm. The collector-emitter voltage was fixed (at 100 V) to provide the active operation mode at any collector current in a wide range from 80 mA to 10 A (current densities of 3.5-445 A cm-2). The maximum current gain steadily grows with Lbe from 8 (Lbe = 3 µm) to 21 (Lbe = 15 µm) at room temperature. For all values of Lbe, β steadily increases as the temperature becomes lower; however, the smaller Lbe is, the weaker the effect produced by temperature lowering. As, for example, the temperature is lowered to -42 °C, β increases from 8 to 9 for structures with Lbe = 3 µm and from 21 to 31 for structures with Lbe = 15 µm. The phenomena observed have been accounted for by recombination at the p+-p base boundary.

  19. Actively phase-controlled coupling between plasmonic waveguides via in-between gain-assisted nanoresonator: nanoscale optical logic gates.

    Science.gov (United States)

    Ho, Kum-Song; Han, Yong-Ha; Ri, Chol-Song; Im, Song-Jin

    2016-08-15

    The development of nanoscale optical logic gates has attracted immense attention due to increasing demand for ultrahigh-speed and energy-efficient optical computing and data processing, however, suffers from the difficulty in precise control of phase difference of the two optical signals. We propose a novel conception of nanoscale optical logic gates based on actively phase-controlled coupling between two plasmonic waveguides via an in-between gain-assisted nanoresonator. Precise control of phase difference between the two plasmonic signals can be performed by manipulating pumping rate at an appropriate frequency detuning, enabling a high contrast between the output logic states "1" and "0." Without modification of the structural parameters, different logic functions can be provided. This active nanoscale optical logic device is expected to be quite energy-efficient with ideally low energy consumption on the order of 0.1 fJ/bit. Analytical calculations and numerical experiments demonstrate the validity of the proposed concept.

  20. High Gain Slot Array with Fabry-Perot Cavity Feeding Circuit

    Directory of Open Access Journals (Sweden)

    Halim Boutayeb

    2016-01-01

    Full Text Available A new approach for designing slot arrays using a Fabry-Perot cavity for the feeding circuit is presented. The proposed array has simpler and smaller feeding circuit compared to conventional feeding networks that have multiple dividers or combiners. The dividers and combiners are usually sources of losses. In addition, the profile of the proposed array is not limited by the half-wavelength resonance condition that exists for Fabry-Perot resonator antennas based on partially reflecting surfaces. The operating frequency is not sensitive to the profile of the antenna. A small profile can be achieved without the utilization of an artificial magnetic conductor or a substrate with high dielectric constant. To validate the proposed approach, full-wave numerical results are presented at 5.8 GHz showing good impedance matching, a high gain of about 22 dB, and an efficiency of 76%.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    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 .

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Spectral Phase Modulation and chirped pulse amplification in High Gain Harmonic Generation

    CERN Document Server

    Wu, Zilu; Krinsky, Sam; Loos, Henrik; Murphy, James; Shaftan, Timur; Sheehy, Brian; Shen, Yuzhen; Wang, Xijie; Yu Li Hua

    2004-01-01

    High Gain Harmonic Generation (HGHG), because it produces longitudinally coherent pulses derived from a coherent seed, presents remarkable possibilities for manipulating FEL pulses. If spectral phase modulation imposed on the seed modulates the spectral phase of the HGHG in a deterministic fashion, then chirped pulse amplification, pulse shaping, and coherent control experiments at short wavelengths become possible. In addition, the details of the transfer function will likely depend on electron beam and radiator dynamics and so prove to be a useful tool for studying these. Using the DUVFEL at the National Synchrotron Light Source at Brookhaven National Laboratory, we present spectral phase analyses of both coherent HGHG and incoherent SASE ultraviolet FEL radiation, applying Spectral Interferometry for Direct Electric Field Reconstruction (SPIDER), and assess the potential for employing compression and shaping techniques.

  10. High Gain and Frequency Ultra-Stable Integrators for ICC and Long Pulse ITER Applications

    Science.gov (United States)

    Miller, Kenneth; Ziemba, Timothy; Prager, James

    2012-10-01

    Eagle Harbor Technologies has developed a high gain and frequency ultra-stable integrator for small scale concept experiments and long pulse ITER applications. The Phase I integrator has a 10 μs RC time with a frequency response greater than 10 MHz. The device has been operated for the 3600 s with a drift error less than 600 μV, which exceeds the ITER specification. Longer period operation is also possible (> 30 hours). Additionally, this integrator has an extremely large dynamic range thereby increasing the effective bit depth of a digitizer. These integrators allow for both the fast and slow magnetic/plasma dynamics to be resolved with a single diagnostic. Data will be presented demonstrating the success of the Phase I program, and the Phase II work plan will be discussed. Work has begun to incorporate the integrators into legacy (CAMAC) and modern (National Instruments) DAQ systems.

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

    OpenAIRE

    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...

  12. Convergent Evolution towards High Net Carbon Gain Efficiency Contributes to the Shade Tolerance of Palms (Arecaceae.

    Directory of Open Access Journals (Sweden)

    Ren-Yi Ma

    Full Text Available Most palm species occur in the shaded lower strata of tropical rain forests, but how their traits relate to shade adaptation is poorly understood. We hypothesized that palms are adapted to the shade of their native habitats by convergent evolution towards high net carbon gain efficiency (CGEn, which is given by the maximum photosynthetic rate to dark respiration rate ratio. Leaf mass per area, maximum photosynthetic rate, dark respiration and N and P concentrations were measured in 80 palm species grown in a common garden, and combined with data of 30 palm species growing in their native habitats. Compared to other species from the global leaf economics data, dicotyledonous broad-leaved trees in tropical rainforest or other monocots in the global leaf economics data, palms possessed consistently higher CGEn, achieved by lowered dark respiration and fairly high foliar P concentration. Combined phylogenetic analyses of evolutionary signal and trait evolution revealed convergent evolution towards high CGEn in palms. We conclude that high CGEn is an evolutionary strategy that enables palms to better adapt to shady environments than coexisting dicot tree species, and may convey advantages in competing with them in the tropical forest understory. These findings provide important insights for understanding the evolution and ecology of palms, and for understanding plant shade adaptations of lower rainforest strata. Moreover, given the dominant role of palms in tropical forests, these findings are important for modelling carbon and nutrient cycling in tropical forest ecosystems.

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

    NARCIS (Netherlands)

    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:

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

    CERN Document Server

    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...

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    -pull circuit with voltage-doubling rectification. The converter's voltage gain is presently not matched by any other converter operating at the same switch duty ratio. The converter also has more degrees of freedom in design for setting the desired gain than other converters, and hence can better meet...

  16. Sensitivity- and effort-gain analysis: multilead ECG electrode array selection for activation time imaging.

    Science.gov (United States)

    Hintermüller, Christoph; Seger, Michael; Pfeifer, Bernhard; Fischer, Gerald; Modre, Robert; Tilg, Bernhard

    2006-10-01

    Methods for noninvasive imaging of electric function of the heart might become clinical standard procedure the next years. Thus, the overall procedure has to meet clinical requirements as an easy and fast application. In this paper, we propose a new electrode array which improves the resolution of methods for activation time imaging considering clinical constraints such as easy to apply and compatibility with routine leads. For identifying the body-surface regions where the body surface potential (BSP) is most sensitive to changes in transmembrane potential (TMP), a virtual array method was used to compute local linear dependency (LLD) maps. The virtual array method computes a measure for the LLD in every point on the body surface. The most suitable number and position of the electrodes within the sensitive body surface regions was selected by constructing effort gain (EG) plots. Such a plot depicts the relative attainable rank of the leadfield matrix in relation to the increase in number of electrodes required to build the electrode array. The attainable rank itself was computed by a detector criterion. Such a criterion estimates the maximum number of source space eigenvectors not covered by noise when being mapped to the electrode space by the leadfield matrix and recorded by a detector. From the sensitivity maps, we found that the BSP is most sensitive to changes in TMP on the upper left frontal and dorsal body surface. These sensitive regions are covered best by an electrode array consisting of two L-shaped parts of approximately 30 cm x 30 cm and approximately 20 cm x 20 cm. The EG analysis revealed that the array meeting clinical requirements best and improving the resolution of activation time imaging consists of 125 electrodes with a regular horizontal and vertical spacing of 2-3 cm.

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

    KAUST Repository

    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.

  18. Transportation-cyber-physical-systems-oriented engine cylinder pressure estimation using high gain observer

    Science.gov (United States)

    Li, Yong-Fu; Xiao-Pei, Kou; Zheng, Tai-Xiong; Li, Yin-Guo

    2015-05-01

    In transportation cyber-physical-systems (T-CPS), vehicle-to-vehicle (V2V) communications play an important role in the coordination between individual vehicles as well as between vehicles and the roadside infrastructures, and engine cylinder pressure is significant for engine diagnosis on-line and torque control within the information exchange process under V2V communications. However, the parametric uncertainties caused from measurement noise in T-CPS lead to the dynamic performance deterioration of the engine cylinder pressure estimation. Considering the high accuracy requirement under V2V communications, a high gain observer based on the engine dynamic model is designed to improve the accuracy of pressure estimation. Then, the analyses about convergence, converge speed and stability of the corresponding error model are conducted using the Laplace and Lyapunov method. Finally, results from combination of Simulink with GT-Power based numerical experiments and comparisons demonstrate the effectiveness of the proposed approach with respect to robustness and accuracy. Project supported by the National Natural Science Foundation of China (Grant No. 61304197), the Scientific and Technological Talents of Chongqing, China (Grant No. cstc2014kjrc-qnrc30002), the Key Project of Application and Development of Chongqing, China (Grant No. cstc2014yykfB40001), the Natural Science Funds of Chongqing, China (Grant No. cstc2014jcyjA60003), and the Doctoral Start-up Funds of Chongqing University of Posts and Telecommunications, China (Grant No. A2012-26).

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    CERN Document Server

    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.

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

    Science.gov (United States)

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

    2016-08-01

    We investigated the use of Hamamatsu fine-mesh photomultiplier tube assemblies H6152-70 and H6614-70 with regard 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.

  3. Transgenic rescue of adipocyte glucose-dependent insulinotropic polypeptide receptor expression restores high fat diet-induced body weight gain

    DEFF Research Database (Denmark)

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

    2011-01-01

    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. High indium content graded channel GainAs/AlinAs pseudomorphic MODFETs

    Science.gov (United States)

    Laskar, J.; Kolodzey, J.; Boor, S.; Hsieh, K. C.; Kalem, S.; Caracci, S.; Ketterson, A. A.; Brock, T.; Adesida, I.; Sivco, D.; Cho, A. Y.

    1990-03-01

    We report on the electrical and microstructural properties of InP/GaxIn 1 -xAs/Al0.48In0.52As modulation doped layers having compositionally graded active channels with different channel thicknesses. The layers were grown by solid source molecular beam epitaxy on Fe-doped InP substrates. The undoped GaInAs two dimensional electron gas channel layers were grown having indium compositions graded from x = 0.53 at the substrate buffer to x= 0.65 at the heterointerface by varying the Ga cell temperature during growth. Active channel thicknesses of 20 nm and 30 nm were compared with lattice matched layers. Transmission electron microscope image analysis indicates no misfit dislocations in these structures. Hall-effect measurements at 300 K show an increase in the mobility from 8,380 cm2/Vs for the lattice matched layer to 12,500 cm2/Vs for the 30 nm pseudomorphic layer. Small gate-length, 0.25 μn, MODFETs were fabricated to determine effective velocity values from transconductance ( g m ) and current gain ( h 21 ) measurements. The peak dc extrinsic g m increased from 367 mS/mm for the lattice matched layer to 668 mS/mm for the 30 nm pseudomorphic layer. The effective electron carrier velocity increased from 1.57 × 107 cm/s for the lattice matched layer to 1.88 × 107 cm/s for the 30 nm pseudomorphic layer. Our results show that compositional grading is a useful technique to obtain thick pseudomorphic layers with good transport properties.

  5. Electrical vagus nerve stimulation decreases food consumption and weight gain in rats fed a high-fat diet.

    Science.gov (United States)

    Gil, Krzysztof; Bugajski, A; Thor, P

    2011-12-01

    There is growing evidence that vagus nerve stimulation (VNS) has a suppressive effect on both short- and long-term feeding in animal models. We previously showed that long-term VNS (102 days) with low-frequency electrical impulses (0.05 Hz) decreased food intake and body weight in rats. In the present study, we investigated the effect of high frequency (10 Hz) VNS on feeding behavior and appetite in rats fed a high-fat diet; peptide secretion and other parameters were assessed as well. Adult male Wistar rats were each implanted subcutaneously with a microstimulator (MS) and fed a high-fat diet throughout the entire study period (42 days). The left vagus nerve was stimulated by rectangular electrical pulses (10 ms, 200 mV, 10 Hz, 12 h a day) generated by the MS. Body weight and food intake were measured each morning. At the end of the experimental period, animals were euthanized and blood samples were taken. Serum levels of ghrelin, leptin and nesfatin-1 were assessed using radioimmunoassays. Adipose tissue content was evaluated by weighing epididymal fat pads, which were incised at the time of sacrifice. To determine whether VNS activated the food-related areas of the brain, neuronal c-Fos induction in the nuclei of the solitary tract (NTS) was assessed. Chronic vagus nerve stimulation significantly decreased food intake, body weight gain and epididymal fat pad weight in animals that received VNS compared with control animals. Significant neuronal responses in the NTS were observed following VNS. Finally, serum concentrations of ghrelin were increased, while serum levels of leptin were decreased. Although not significant, serum nesfatin-1 levels were also elevated. These results support the theory that VNS leads to reductions in food intake, body weight gain and adipose tissue by increasing brain satiety signals conducted through the vagal afferents. VNS also evoked a feed-related hormonal response, including elevated blood concentrations of nesfatin-1.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

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

    2016-04-14

    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.

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

    Science.gov (United States)

    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

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

    International Nuclear Information System (INIS)

    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

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

    CERN Document Server

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    OpenAIRE

    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...

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

    Science.gov (United States)

    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

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

    DEFF Research Database (Denmark)

    Gaunholt, Hans; Guldbrandsen, Birthe

    1997-01-01

    analog filters in voltage-mode as well as current-mode technology. As an example we will choose the band-pass biquad as biquads of this type often has to be designed with high-Q values. The results in the band-pass case may readily be transferred to the low-pass and high-pass cases.......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...

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    The paper presents analysis and design of a Q-band subharmonic mixer (SHM) with high conversion gain. The SHM consists of a local oscillator (LO) frequency doubler, RF pre-amplifier, and single-ended mixer. The SHM has been fabricated in a high-speed InP double heterojunction bipolar transistor...

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

    Science.gov (United States)

    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…

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

    CERN Document Server

    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 ...

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

    NARCIS (Netherlands)

    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,

  20. Double-pass ytterbium-doped fiber amplifier with high gain coefficient and low noise figure

    Institute of Scientific and Technical Information of China (English)

    Anting Wang(王安廷); Meishu Xing(邢美术); Guanghui Chen(陈光辉); Wenkui Yang(杨文奎); Hai Ming(明海); Jianping Xie(谢建平); Yunxia Wu(吴云霞)

    2003-01-01

    We have proposed and demonstrated a double-pass ytterbium-doped fiber amplifier using an optical circulator and a fiber Bragg grating as reflector. When the signal has passed through the ytterbium-doped fiber once, it reflects off a 0.2-nm passive fiber Bragg grating filter. This reduces amplified spontaneous emission (ASE) noise from the first pass. The input signal light is amplified both forward and backward through ytterbium-doped fiber. With this double-pass configuration, 1053.15-nm unsaturated signal gain of 28 dB, gain coefficient of 1.1 dB/mW, and noise figure of less than 4 dB are achieved at 977-nm pump power of 68 mW. It is also found that this double-pass configure provides enhancing gain coefficient and improving noise figure by comparison with single-pass configuration.

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

    OpenAIRE

    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 ...

  2. Novel T-Z source inverter with high voltage gain and reduced transformer turn ratio

    DEFF Research Database (Denmark)

    Mostaan, Ali; Sharifi Malfejani, Saeed; Soltani, Mohsen;

    2015-01-01

    Novel voltage source inverter based on the Z source inverter structure is introduced in this paper. In this new inverter, two inductors of the impedance network in conventional Z source inverter are replaced with two transformers or coupled inductors, but unlike the T-Z source inverter that it......'s voltage gain is raised with increasing the transformers turn ratio, the voltage gain in the proposed inverter is raised with lowering the transformer turn ratio. Therefore, transformers with lower turn ratio are required in the proposed inverter in compare with T- Z source inverter that can lead to lower...

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    OpenAIRE

    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...

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

    OpenAIRE

    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...

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

    Institute of Scientific and Technical Information of China (English)

    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.

  7. Gain-of-function STAT1 mutations impair STAT3 activity in patients with chronic mucocutaneous candidiasis (CMC).

    Science.gov (United States)

    Zheng, Jie; van de Veerdonk, Frank L; Crossland, Katherine L; Smeekens, Sanne P; Chan, Chun M; Al Shehri, Tariq; Abinun, Mario; Gennery, Andrew R; Mann, Jelena; Lendrem, Dennis W; Netea, Mihai G; Rowan, Andrew D; Lilic, Desa

    2015-10-01

    Signal transducer and activator of transcription 3 (STAT3) triggered production of Th-17 cytokines mediates protective immunity against fungi. Mutations affecting the STAT3/interleukin 17 (IL-17) pathway cause selective susceptibility to fungal (Candida) infections, a hallmark of chronic mucocutaneous candidiasis (CMC). In patients with autosomal dominant CMC, we and others previously reported defective Th17 responses and underlying gain-of-function (GOF) STAT1 mutations, but how this affects STAT3 function leading to decreased IL-17 is unclear. We also assessed how GOF-STAT1 mutations affect STAT3 activation, DNA binding, gene expression, cytokine production, and epigenetic modifications. We excluded impaired STAT3 phosphorylation, nuclear translocation, and sequestration of STAT3 into STAT1/STAT3 heterodimers and confirm significantly reduced transcription of STAT3-inducible genes (RORC/IL-17/IL-22/IL-10/c-Fos/SOCS3/c-Myc) as likely underlying mechanism. STAT binding to the high affinity sis-inducible element was intact but binding to an endogenous STAT3 DNA target was impaired. Reduced STAT3-dependent gene transcription was reversed by inhibiting STAT1 activation with fludarabine or enhancing histone, but not STAT1 or STAT3 acetylation with histone deacetylase (HDAC) inhibitors trichostatin A or ITF2357. Silencing HDAC1, HDAC2, and HDAC3 indicated a role for HDAC1 and 2. Reduced STAT3-dependent gene transcription underlies low Th-17 responses in GOF-STAT1 CMC, which can be reversed by inhibiting acetylation, offering novel targets for future therapies.

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

    NARCIS (Netherlands)

    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.

  9. Quantum spatial correlations in high-gain parametric down-conversion measured by means of a CCD camera

    DEFF Research Database (Denmark)

    Jedrkiewicz, O.; Brambilla, E.; Bache, Morten;

    2006-01-01

    We consider travelling-wave parametric down-conversion in the high-gain regime and present the experimental demonstration of the quantum character of the spatial fluctuations in the system. In addition to showing the presence of sub-shot noise fluctuations in the intensity difference, we demonstr...

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

    DEFF Research Database (Denmark)

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

    2007-01-01

    This paper addresses state estimation and linear quadratic (LQ) control of variable speed variable pitch wind turbines. On the basis of a nonlinear model of a wind turbine, a set of operating conditions is identified and a LQ controller is designed for each operating point. The controller gains....... Simulation results are given that display good performance of the observers and comparisons with a controller designed by classical methods displays the potential of the method.  ...

  11. High Gain Superstrate Loaded Membrane Antenna Based on Substrate Integrated Waveguide Technology

    Directory of Open Access Journals (Sweden)

    Hamsakutty Vettikalladi

    2015-01-01

    Full Text Available The design and the results of a single slot coupled substrate integrated waveguide (SIW fed membrane antenna loaded with a superstrate layer are presented for 94 GHz communication system. The membrane antenna is designed using ANSYS HFSS and consists of 6 layers. The microstrip patch antenna (MPA placed on the top pyralux substrate layer is excited by means of a longitudinal rectangular slot placed over the SIW structure in the bottom pyralux substrate. The simulated antenna impedance bandwidth is found to be 5 GHz (91.5–96.5 GHz with a gain of 7 dBi. In order to improve the gain a superstrate layer is added above the membrane antenna. The maximum gain achieved is 14.4 dBi with an efficiency of 77.6% at 94 GHz. The results are verified using CST Microwave Studio and are found to be in good agreement.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    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.

  14. High gain CMOS image sensor design and fabrication on SOI and bulk technology

    Science.gov (United States)

    Zhang, Weiquan

    2000-12-01

    The CMOS imager is now competing with the CCD imager, which still dominates the electronic imaging market. By taking advantage of the mature CMOS technology, the CMOS imager can integrate AID converters, digital signal processing (DSP) and timing control circuits on the same chip. This low cost and high-density integration solution to the image capture is the strong driving force in industry. Silicon on insulator (SOI) is considered as the coming mainstream technology. It challenges the current bulk CMOS technology because of its reduced power consumption, high speed, radiation hardness etc. Moving the CMOS imager from the bulk to the SOI substrate will benefit from these intrinsic advantages. In addition, the blooming and the cross-talk between the pixels of the sensor array can be ideally eliminated, unlike those on the bulk technology. Though there are many advantages to integrate CMOS imager on SOI, the problem is that the top silicon film is very thin, such as 2000Å. Many photons can just pass through this layer without being absorbed. A good photo-detector on SOI is critical to integrate SOI CMOS imagers. In this thesis, several methods to make photo-detectors on SOI substrate are investigated. A floating gate MOSFET on SOI substrate, operating in its lateral bipolar mode, is photon sensitive. One step further, the SOI MOSFET gate and body can be tied together. The positive feedback between the body and gate enables this device have a high responsivity. A similar device can be found on the bulk CMOS technology: the gate-well tied PMOSFET. A 32 x 32 CMOS imager is designed and characterized using such a device as the light-sensing element. I also proposed the idea of building hybrid active pixels on SOI substrate. Such devices are fabricated and characterized. The work here represents my contribution on the CMOS imager, especially moving the CMOS imager onto the SOI substrate.

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

    OpenAIRE

    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...

  16. Attentional bias toward high-calorie food-cues and trait motor impulsivity interactively predict weight gain

    Directory of Open Access Journals (Sweden)

    Adrian Meule

    2016-05-01

    Full Text Available Strong bottom-up impulses and weak top-down control may interactively lead to overeating and, consequently, weight gain. In the present study, female university freshmen were tested at the start of the first semester and again at the start of the second semester. Attentional bias toward high- or low-calorie food-cues was assessed using a dot-probe paradigm and participants completed the Barratt Impulsiveness Scale. Attentional bias and motor impulsivity interactively predicted change in body mass index: motor impulsivity positively predicted weight gain only when participants showed an attentional bias toward high-calorie food-cues. Attentional and non-planning impulsivity were unrelated to weight change. Results support findings showing that weight gain is prospectively predicted by a combination of weak top-down control (i.e. high impulsivity and strong bottom-up impulses (i.e. high automatic motivational drive toward high-calorie food stimuli. They also highlight the fact that only specific aspects of impulsivity are relevant in eating and weight regulation.

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

    Science.gov (United States)

    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

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

    DEFF Research Database (Denmark)

    Xu, Zhangcheng; Birkedal, Dan; Juhl, Michael;

    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...

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

    OpenAIRE

    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...

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

    International Nuclear Information System (INIS)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Science.gov (United States)

    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. Excess Folic Acid Increases Lipid Storage, Weight Gain, and Adipose Tissue Inflammation in High Fat Diet-Fed Rats

    Science.gov (United States)

    Kelly, Karen B.; Kennelly, John P.; Ordonez, Marta; Nelson, Randal; Leonard, Kelly; Stabler, Sally; Gomez-Muñoz, Antonio; Field, Catherine J.; Jacobs, René L.

    2016-01-01

    Folic acid intake has increased to high levels in many countries, raising concerns about possible adverse effects, including disturbances to energy and lipid metabolism. Our aim was to investigate the effects of excess folic acid (EFA) intake compared to adequate folic acid (AFA) intake on metabolic health in a rodent model. We conducted these investigations in the setting of either a 15% energy low fat (LF) diet or 60% energy high fat (HF) diet. There was no difference in weight gain, fat mass, or glucose tolerance in EFA-fed rats compared to AFA-fed rats when they were fed a LF diet. However, rats fed EFA in combination with a HF diet had significantly greater weight gain and fat mass compared to rats fed AFA (p adipose tissue of high fat-excess folic acid (HF-EFA) fed rats. Inflammation was increased in HF-EFA fed rats, associated with impaired glucose tolerance compared to high fat-adequate folic acid (HF-AFA) fed rats (p < 0.05). In addition, folic acid induced PPARγ expression and triglyceride accumulation in 3T3-L1 cells. Our results suggest that excess folic acid may exacerbate weight gain, fat accumulation, and inflammation caused by consumption of a HF diet. PMID:27669293

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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).

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

    International Nuclear Information System (INIS)

    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)

  7. High Magnetic Shear Gain in a Liquid Sodium Stable Couette Flow Experiment; A Prelude to an alpha-Omega Dynamo

    CERN Document Server

    Colgate, Stirling A; Pariev, Vladimir; Finn, John; Beckley, Howard; Si, Jiahe; Martinic, Joe; Westpfahl, David; Slutz, James; Westrom, Cebastian; Klein, Brianna; Schendel, Paul; Scharle, Cletus; McKinney, Travis; Ginanni, Rocky; Bentley, Ian; Mickey, Timothy

    2010-01-01

    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, $B_{\\phi} \\simeq 8\\times B_r$ from the radial component of an applied poloidal magnetic field, $B_r$. This enhanced toroidal field is produced by rotational shear in stable Couette flow within liquid sodium at $Rm \\simeq 120$. The small turbulence in stable Taylor-Couette flow is caused by Ekman flow where $ (\\delta v/v)^2 \\sim 10^{-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 only a smaller diffusive role that enables magnetic flux linkage.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

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

    OpenAIRE

    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 ...

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

    Directory of Open Access Journals (Sweden)

    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. On the Fielding of a High Gain, Shock-Ignited Target on the National Ignitiion Facility in the Near Term

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, L J; Betti, R; Schurtz, G P; Craxton, R S; Dunne, A M; LaFortune, K N; Schmitt, A J; McKenty, P W; Bailey, D S; Lambert, M A; Ribeyre, X; Theobald, W R; Strozzi, D J; Harding, D R; Casner, A; Atzemi, S; Erbert, G V; Andersen, K S; Murakami, M; Comley, A J; Cook, R C; Stephens, R B

    2010-04-12

    Shock ignition, a new concept for igniting thermonuclear fuel, offers the possibility for a near-term ({approx}3-4 years) test of high gain inertial confinement fusion on the National Ignition Facility at less than 1MJ drive energy and without the need for new laser hardware. In shock ignition, compressed fusion fuel is separately ignited by a strong spherically converging shock and, because capsule implosion velocities are significantly lower than those required for conventional hotpot ignition, fusion energy gains of {approx}60 may be achievable on NIF at laser drive energies around {approx}0.5MJ. Because of the simple all-DT target design, its in-flight robustness, the potential need for only 1D SSD beam smoothing, minimal early time LPI preheat, and use of present (indirect drive) laser hardware, this target may be easier to field on NIF than a conventional (polar) direct drive hotspot ignition target. Like fast ignition, shock ignition has the potential for high fusion yields at low drive energy, but requires only a single laser with less demanding timing and spatial focusing requirements. Of course, conventional symmetry and stability constraints still apply. In this paper we present initial target performance simulations, delineate the critical issues and describe the immediate-term R&D program that must be performed in order to test the potential of a high gain shock ignition target on NIF in the near term.

  13. Quercetin decreases high-fat diet induced body weight gain and accumulation of hepatic and circulating lipids in mice.

    Science.gov (United States)

    Hoek-van den Hil, E F; van Schothorst, E M; van der Stelt, I; Swarts, H J M; Venema, D; Sailer, M; Vervoort, J J M; Hollman, P C H; Rietjens, I M C M; Keijer, J

    2014-09-01

    Dietary flavonoids may protect against cardiovascular diseases (CVD). Increased circulating lipid levels and hepatic lipid accumulation are known risk factors for CVD. The aim of this study was to investigate the effects and underlying molecular mechanisms of the flavonoid quercetin on hepatic lipid metabolism in mice with high-fat diet induced body weight gain and hepatic lipid accumulation. Adult male mice received a 40 energy% high-fat diet without or with supplementation of 0.33 % (w/w) quercetin for 12 weeks. Body weight gain was 29 % lower in quercetin fed mice (p lipid accumulation to 29 % of the amount present in the control mice (p lipid profiling revealed that the supplementation significantly lowered serum lipid levels. Global gene expression profiling of liver showed that cytochrome P450 2b (Cyp2b) genes, key target genes of the transcription factor constitutive androstane receptor (Car; official symbol Nr1i3), were downregulated. Quercetin decreased high-fat diet induced body weight gain, hepatic lipid accumulation and serum lipid levels. This was accompanied by regulation of cytochrome P450 2b genes in liver, which are possibly under transcriptional control of CAR. The quercetin effects are likely dependent on the fat content of the diet.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

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

    NARCIS (Netherlands)

    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

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

    NARCIS (Netherlands)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Data.gov (United States)

    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...

  1. Temperature dependency of the Ga/In distribution in Cu(In,Ga)Se2 absorbers in high temperature processes

    Science.gov (United States)

    Mueller, B. J.; Demes, T.; Lill, P. C.; Haug, V.; Hergert, F.; Zweigart, S.; Herr, U.

    2016-05-01

    The current article reports about the influence of temperature and glass substrate on Ga/In interdiffusion and chalcopyrite phase formation in the stacked elemental layer process. According to the Shockley-Queisser limit the optimum for single junction devices is near 1.4 eV, which is strongly coupled on the Ga/(Ga+In) ratio of Cu(In,Ga)Se2 thin film solar cells. To increase the Ga content in the active region of the Cu(In,Ga)Se2 a 70:30 CuGa alloy target is used. An increase of the selenization temperature leads to a more homogeneous Ga/In distribution and a less pronounced Ga agglomeration at the back contact. The Ga/In interdiffusion rates for different selenization temperatures and substrates were estimated with the model of a two layer system. At the highest selenization temperature used an absorber band gap of 1.12 eV was realized, which is similar to typical values of absorbers produced during the co-evaporation process. The Na diffusion into the Cu(In,Ga)Se2 is weakly temperature dependent but strongly influenced by the choice of the glass substrate composition.

  2. Cortical activation changes underlying stimulation-induced behavioural gains in chronic stroke.

    Science.gov (United States)

    Stagg, Charlotte Jane; Bachtiar, Velicia; O'Shea, Jacinta; Allman, Claire; Bosnell, Rosemary Ann; Kischka, Udo; Matthews, Paul McMahan; Johansen-Berg, Heidi

    2012-01-01

    Transcranial direct current stimulation, a form of non-invasive brain stimulation, is showing increasing promise as an adjunct therapy in rehabilitation following stroke. However, although significant behavioural improvements have been reported in proof-of-principle studies, the underlying mechanisms are poorly understood. The rationale for transcranial direct current stimulation as therapy for stroke is that therapeutic stimulation paradigms increase activity in ipsilesional motor cortical areas, but this has not previously been directly tested for conventional electrode placements. This study was performed to test directly whether increases in ipsilesional cortical activation with transcranial direct current stimulation are associated with behavioural improvements in chronic stroke patients. Patients at least 6 months post-first stroke participated in a behavioural experiment (n = 13) or a functional magnetic resonance imaging experiment (n = 11), each investigating the effects of three stimulation conditions in separate sessions: anodal stimulation to the ipsilesional hemisphere; cathodal stimulation to the contralesional hemisphere; and sham stimulation. Anodal (facilitatory) stimulation to the ipsilesional hemisphere led to significant improvements (5-10%) in response times with the affected hand in both experiments. This improvement was associated with an increase in movement-related cortical activity in the stimulated primary motor cortex and functionally interconnected regions. Cathodal (inhibitory) stimulation to the contralesional hemisphere led to a functional improvement only when compared with sham stimulation. We show for the first time that the significant behavioural improvements produced by anodal stimulation to the ipsilesional hemisphere are associated with a functionally relevant increase in activity within the ipsilesional primary motor cortex in patients with a wide range of disabilities following stroke.

  3. A novel 3-stage structure for a low-noise, high-gain and gain-flattened L-band erbium doped fiber amplifier

    Institute of Scientific and Technical Information of China (English)

    强则煊; 何赛灵; 张徐亮; 沈林放

    2004-01-01

    The configuration of the novel three-stage L-band erbium-doped fiber amplifier with very large and flat gain and very low noise figure presented in this paper uses the forward ASE (amplified spontaneous emission) from the first section of the EDF (erbium-doped fiber) and the backward ASE from the third section of the EDF (both serve as the secondary pump sources of energy) to pump the second EDF. To improve the pump efficiency, the power of the pump is split into two parts (with a ratio of e.g. 2:7). The characteristics of this L-band EDFA are studied on the basis of the Giles Model with ASE.

  4. A novel 3-stage structure for a low-noise, high-gain and gain-flattened L-band erbium doped fiber amplifier

    Institute of Scientific and Technical Information of China (English)

    强则煊; 何赛灵; 张徐亮; 沈林放

    2004-01-01

    The configuration of the novel three-stage L-band erbium-doped fiber amplifier with very large and flat gain and very low noise figure presented in this paper uses the forward ASE (amplified spontaneous emission) from the first section of the EDF (erbium-doped fiber) and the backward AS E from the third section of the EDF (both serve as the secondary pump sources of energy) to pump the second EDF. To improve the pump efficiency, the power of the pump is split into two parts(with a ratio of e.g. 2:7). The characteristics of this L-band EDFA are studied on the basis of the Giles Model with ASE.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    OpenAIRE

    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 ...

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

    OpenAIRE

    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. Excess Folic Acid Increases Lipid Storage, Weight Gain, and Adipose Tissue Inflammation in High Fat Diet-Fed Rats.

    Science.gov (United States)

    Kelly, Karen B; Kennelly, John P; Ordonez, Marta; Nelson, Randal; Leonard, Kelly; Stabler, Sally; Gomez-Muñoz, Antonio; Field, Catherine J; Jacobs, René L

    2016-01-01

    Folic acid intake has increased to high levels in many countries, raising concerns about possible adverse effects, including disturbances to energy and lipid metabolism. Our aim was to investigate the effects of excess folic acid (EFA) intake compared to adequate folic acid (AFA) intake on metabolic health in a rodent model. We conducted these investigations in the setting of either a 15% energy low fat (LF) diet or 60% energy high fat (HF) diet. There was no difference in weight gain, fat mass, or glucose tolerance in EFA-fed rats compared to AFA-fed rats when they were fed a LF diet. However, rats fed EFA in combination with a HF diet had significantly greater weight gain and fat mass compared to rats fed AFA (p high fat-excess folic acid (HF-EFA) fed rats. Inflammation was increased in HF-EFA fed rats, associated with impaired glucose tolerance compared to high fat-adequate folic acid (HF-AFA) fed rats (p fat accumulation, and inflammation caused by consumption of a HF diet. PMID:27669293

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

    OpenAIRE

    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 ...

  11. Normal hematopoiesis and lack of β-catenin activation in osteoblasts of patients and mice harboring Lrp5 gain-of-function mutations

    DEFF Research Database (Denmark)

    Galán-Díez, Marta; Isa, Adiba; Ponzetti, Marco;

    2016-01-01

    of hematopoiesis and leukemogenic properties of β-catenin activation in osteoblasts, that lead to development of acute myeloid leukemia (AML). Using mice with gain-of-function (GOF) Lrp5 alleles (Lrp5(A214V)) that recapitulate the human high bone mass (HBM) phenotype, as well as patients with the T253I HBM Lrp5......Osteoblasts are emerging regulators of myeloid malignancies since genetic alterations in them, such as constitutive activation of β-catenin, instigate their appearance. The LDL receptor-related protein 5 (LRP5), initially proposed to be a co-receptor for Wnt proteins, in fact favors bone formation...... patients showed normal hematopoiesis, normal percentage of myeloid cells, and lack of anemia. We conclude that Lrp5 GOF mutations do not activate β-catenin signaling in osteoblasts. As a result, myeloid lineage differentiation is normal in HBM patients and mice. This article is part of a Special Issue...

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

    DEFF Research Database (Denmark)

    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

    Science.gov (United States)

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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

  16. Ultrahigh gain AlGaN/GaN high energy radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    Simone Zuffanelli

    2016-07-01

    Full Text Available 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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    NARCIS (Netherlands)

    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

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

    NARCIS (Netherlands)

    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

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

    NARCIS (Netherlands)

    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

  8. Solidification of highly active wastes

    International Nuclear Information System (INIS)

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    KAUST Repository

    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.

  12. The effects of acute stress exposure on striatal activity during Pavlovian conditioning with monetary gains and losses.

    Science.gov (United States)

    Lewis, Andrea H; Porcelli, Anthony J; Delgado, Mauricio R

    2014-01-01

    Pavlovian conditioning involves the association of an inherently neutral stimulus with an appetitive or aversive outcome, such that the neutral stimulus itself acquires reinforcing properties. Across species, this type of learning has been shown to involve subcortical brain regions such as the striatum and the amygdala. It is less clear, however, how the neural circuitry involved in the acquisition of Pavlovian contingencies in humans, particularly in the striatum, is affected by acute stress. In the current study, we investigate the effect of acute stress exposure on Pavlovian conditioning using monetary reinforcers. Participants underwent a partial reinforcement conditioning procedure in which neutral stimuli were paired with high and low magnitude monetary gains and losses. A between-subjects design was used, such that half of the participants were exposed to cold stress while the remaining participants were exposed to a no stress control procedure. Cortisol measurements and subjective ratings were used as measures of stress. We observed an interaction between stress, valence, and magnitude in the ventral striatum, with the peak in the putamen. More specifically, the stress group exhibited an increased sensitivity to magnitude in the gain domain. This effect was driven by those participants who experienced a larger increase in circulating cortisol levels in response to the stress manipulation. Taken together, these results suggest that acute stress can lead to individual differences in circulating cortisol levels which influence the striatum during Pavlovian conditioning with monetary reinforcers.

  13. On high-speed cross-gain modulation without pattern effects in quantum dot semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Uskov, A.V.; Mørk, Jesper; Tromborg, Bjarne;

    2003-01-01

    In the regime with maximum linear gain in a quantum dot (QD) semiconductor optical amplifier (SOA), instantaneous gain modulation by change of the photon density is possible due to spectral hole burning effects. This, in turn, leads to the opportunity of ultrafast cross-gain modulation (XGM...

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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    CERN Document Server

    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...

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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)

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

    DEFF Research Database (Denmark)

    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...

  1. Modeling and output tracking of transverse flux permanent magnet machines using high gain observer and RBF neural network.

    Science.gov (United States)

    Karimi, H R; Babazadeh, A

    2005-10-01

    This paper deals with modeling and adaptive output tracking of a transverse flux permanent magnet machine as a nonlinear system with unknown nonlinearities by utilizing high gain observer and radial basis function networks. The proposed model is developed based on computing the permeance between rotor and stator using quasiflux tubes. Based on this model, the techniques of feedback linearization and Hinfinity control are used to design an adaptive control law for compensating the unknown nonlinear parts, such as the effect of cogging torque, as a disturbance is decreased onto the rotor angle and angular velocity tracking performances. Finally, the capability of the proposed method in tracking both the angle and the angular velocity is shown in the simulation results.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    CERN Document Server

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    CERN Document Server

    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...

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

  13. Sensor fault detection and isolation via high-gain observers: application to a double-pipe heat exchanger.

    Science.gov (United States)

    Escobar, R F; Astorga-Zaragoza, C M; Téllez-Anguiano, A C; Juárez-Romero, D; Hernández, J A; Guerrero-Ramírez, G V

    2011-07-01

    This paper deals with fault detection and isolation (FDI) in sensors applied to a concentric-pipe counter-flow heat exchanger. The proposed FDI is based on the analytical redundancy implementing nonlinear high-gain observers which are used to generate residuals when a sensor fault is presented (as software sensors). By evaluating the generated residual, it is possible to switch between the sensor and the observer when a failure is detected. Experiments in a heat exchanger pilot validate the effectiveness of the approach. The FDI technique is easy to implement allowing the industries to have an excellent alternative tool to keep their heat transfer process under supervision. The main contribution of this work is based on a dynamic model with heat transfer coefficients which depend on temperature and flow used to estimate the output temperatures of a heat exchanger. This model provides a satisfactory approximation of the states of the heat exchanger in order to allow its implementation in a FDI system used to perform supervision tasks.

  14. High-power active devices

    CERN Document Server

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    OpenAIRE

    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...

  18. Performance, carcass characteristics and gain cost of feedlot cattle fed a high level of concentrate and different feed additives

    Directory of Open Access Journals (Sweden)

    Érico Rodrigues

    2013-01-01

    Full Text Available The objective of this study was to evaluate the effects of feeding cattle with isoprotein and isoenergetic diets, with and without the addition of polyclonal antibody preparation (PAP, yeasts (YST or monensin sodium (MON on performance, carcass characteristics and gain cost in feedlot. Ninety-five 20-month old bullocks (323.3±21.8 kg were distributed in 25 pens. The completely randomized experimental design had a 2 × 2 + 1 factorial arrangement and the treatments were replicated 5 times. There was no effect of MON for DMI throughout the feedlot period; however, MON reduced the dry matter intake (DMI in g/kg of BW in the first 28 days when compared with the other treatments. The gain cost decreased with MON addition in relation to the other treatments. Inclusion of YST decreased average daily gain (ADG, final body weight, hot carcass weight, carcass weight, gain to feed ratio and DMI in g/kg body weight, worsening feed conversion and increasing the gain cost in the feeding periods. Inclusion of PAP increased ADG and decreased the gain cost, besides improving feed conversion. For MON and PAP, a difference was found for kidney-pelvic fat and kidney-pelvic fat per 100 kg of hot carcass weight. For MON and YST, there was a difference in ADG, feed conversion, gain cost and carcass yield and kidney-pelvic fat per 100 kg of hot carcass. Treatment YST worsened performance in relation to the non-supplemented treatments. Feeding PAP to animals did not influence performance and carcass characteristics of bullocks in feedlot negatively. Thus, PAP shows potential to substitute MON in cattle feeding using isoprotein and isoenergetic diets.

  19. Net Gains

    Science.gov (United States)

    Fielker, David

    2008-01-01

    The Easter conference 2008 had several activities which for the author raised the same questions on cube nets in some work with eight-year-olds some time ago. In this article, the author muses on some problems from the Easter conference regarding nets of shapes. (Contains 1 note.)

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

    Science.gov (United States)

    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

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

    OpenAIRE

    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...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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

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

    OpenAIRE

    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...

  8. 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

    Science.gov (United States)

    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...

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

    CERN Document Server

    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...

  10. High Gain Rectangular Microstrip Patch Antenna Employing FR4 Substrate for Wi-MAX, LMDS and MMDS Applications

    Directory of Open Access Journals (Sweden)

    Jaspreet Singh

    2016-06-01

    Full Text Available This paper presents an antenna for WiMAX, LMDS and MMDS system applications. FR4 material has been used as substrate having dielectric constant of 4.4. The Patch, Ground and feedline are made of copper. The proposed antenna is rectangular in shape which resonate at 3.42 GHz with a bandwidth of 45MHz (3.40GHz- 3.44GHz and corresponding return loss of -32.39 dB. The performance of the antenna has been analyzed in terms of return loss (dB, gain (dB, directivity (dBi, VSWR and impedance (ohms. The proposed antenna has directivity and gain of 7.2 dBi and 7.28 dB respectively

  11. High-gain complementary metal-oxide-semiconductor inverter based on multi-layer WSe2 field effect transistors without doping

    Science.gov (United States)

    Kang, Won-Mook; Cho, In-Tak; Roh, Jeongkyun; Lee, Changhee; Lee, Jong-Ho

    2016-10-01

    A high-gain complementary metal-oxide-semiconductor (CMOS) logic inverter was implemented by fabricating p- and n-type field effect transistors (FETs) based on multi-layer WSe2 on the same wafer. Au as a high work-function metal is contacted to WSe2 for the source/drain of the p-type FET. The n-type FET has an Al electrode contacted to WSe2 for the source/drain. Both FETs were designed to have similar on-current densities (>10-7 A μm-1) and high on/off current ratios (>106). The inverter shows excellent switching characteristics including relatively high voltage gains (>25) and high noise margins (>0.9) in the range of supply voltage from 2 V to 8 V. This work has a great significance in the realization of a CMOS logic gate based on WSe2 without an additional doping scheme.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. 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

    Directory of Open Access Journals (Sweden)

    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.

  14. High net modal gain (>100 cm(-1)) in 19-stacked InGaAs quantum dot laser diodes at 1000 nm wavelength band.

    Science.gov (United States)

    Tanoue, Fumihiko; Sugawara, Hiroharu; Akahane, Kouichi; Yamamoto, Naokatsu

    2013-07-01

    An InGaAs quantum dot (QD) laser diode with 19-stacked QDs separated by 20 nm-thick GaAs spacers was fabricated using an ultrahigh-rate molecular beam epitaxial growth technique, and the laser characteristics were evaluated. A 19-stacked simple broad area QD laser diode was lased at the 1000 nm waveband. A net modal gain of 103 cm(-1) was obtained at 2.25 kA/cm(2), and the saturated modal gain was 145.6 cm(-1); these are the highest values obtained to our knowledge. These results indicate that using this technique to highly stack QDs is effective for improving the net modal gain of QD lasers.

  15. Merged beam laser design for reduction of gain-saturation and two-photon absorption in high power single mode semiconductor lasers.

    Science.gov (United States)

    Lysevych, M; Tan, H H; Karouta, F; Fu, L; Jagadish, C

    2013-04-01

    In this paper we report a method to overcome the limitations of gain-saturation and two-photon absorption faced by developers of high power single mode InP-based lasers and semiconductor optical amplifiers (SOA) including those based on wide-waveguide or slab-coupled optical waveguide laser (SCOWL) technology. The method is based on Y-coupling design of the laser cavity. The reduction in gain-saturation and two-photon absorption in the merged beam laser structures (MBL) are obtained by reducing the intensity of electromagnetic field in the laser cavity. Standard ridge-waveguide lasers and MBLs were fabricated, tested and compared. Despite a slightly higher threshold current, the reduced gain-saturation in MBLs results in higher output power. The MBLs also produced a single spatial mode, as well as a strongly dominating single spectral mode which is the inherent feature of MBL-type cavity.

  16. Single crystalline Er2O3:sapphire films as potentially high-gain amplifiers at telecommunication wavelength

    International Nuclear Information System (INIS)

    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

  17. Improving proliferation resistance of high breeding gain generation 4 reactors using blankets composed of light water reactor waste

    Energy Technology Data Exchange (ETDEWEB)

    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)

  18. Broadband and high-speed swept external-cavity laser using a quantum-dot superluminescent diode as gain device

    Institute of Scientific and Technical Information of China (English)

    胡发杰; 金鹏; 吴艳华; 王飞飞; 魏恒; 王占国

    2015-01-01

    A wide wavelength tuning range swept external-cavity laser using an InAs/GaAs quantum-dot superluminescent diode as a gain device is demonstrated. The tunable filter consists of a polygon scanner and a grating in Littrow telescope-less configuration. The swept laser generates greater than 54-mW peak output power and up to 33-kHz sweep rate with a sweep range of 150 nm centered at 1155 nm. The effects of injection current and sweep rate on the sweep performance of the swept laser are studied.

  19. Solidification of highly active wastes

    International Nuclear Information System (INIS)

    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)

  20. Active video games as a tool to prevent excessive weight gain in adolescents: rationale, design and methods of a randomized controlled trial

    Science.gov (United States)

    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

  1. 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

    DEFF Research Database (Denmark)

    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...... targets and thus, this age group should avoid this combination. Decreasing target sizes (i.e. increasing visual demand) reduced performance in both groups despite that motor demand was maintained constant. Therefore, it is recommended to avoid small screen objects and letters. Forearm muscle activity...

  2. High-power 1.25 µm InAs QD VECSEL based on resonant periodic gain structure

    Science.gov (United States)

    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.

  3. Study and application of hole structures as gas gain devices for two dimensional high rate X-ray detectors

    Science.gov (United States)

    Sarvestani, A.; Besch, H. J.; Junk, M.; Meißner, W.; Sauer, N.; Stiehler, R.; Walenta, A. H.; Menk, R. H.

    1998-02-01

    Recent developments in hole structures seem to be a promising enrichment for gas-filled photon counters. Up to now, only few investigations of the performance and limitations of these structures have been carried out. In this work a micro-hole structure is presented together with investigations focused on applications with position sensitive pressurized X-ray detectors for synchrotron radiation. In particular, position resolution, gas gain, rate capability, drift field influence and pressure behavior have been studied. In addition, first two dimensional X-ray images have been measured using a gas amplifying micro-hole structure in combination with a resistive position encoding structure. Since different types of hole structures were tested, predictions of structure geometries adapted for specific applications were carried out.

  4. Eight week exposure to a high sugar high fat diet results in adiposity gain and alterations in metabolic biomarkers in baboons (Papio hamadryas sp.

    Directory of Open Access Journals (Sweden)

    Tejero M Elizabeth

    2010-10-01

    Full Text Available Abstract Background Baboons (Papio hamadryas Sp. develop features of the cardiometabolic syndrome and represent a clinically-relevant animal model in which to study the aetiology of the disorder. To further evaluate the baboon as a model for the study of the cardiometabolic syndrome, we developed a high sugar high fat diet and hypothesized that it could be used to induce adiposity gain and affect associated circulating biomarkers. Methods We developed a diet enriched with monosaccharides and saturated fatty acids that was composed of solid and liquid energy sources. We provided a group of baboons (n = 9 ad libitum access to this diet for 8 weeks. Concurrently, a control group (n = 6 was maintained with ad libitum access to a low sugar low fat baseline diet and normal water for 8 weeks. Body composition was determined by dual-energy X-ray absorptiometry and circulating metabolic biomarkers were measured using standard methodology before and after the 8 week study period. Results Neither body composition nor circulating biomarkers changed in the control group. Following the 8 weeks, the intervention group had a significant increase in fat mass (1.71 ± 0.98 vs. 3.23 ± 1.70 kg, p = 0.004, triglyceride (55 ± 13 vs. 109 ± 67 mg/dL, p = 0.006,, and leptin (1.19 ± 1.40 vs. 3.29 ± 2.32 ng/mL, p = 0.001 and a decline in adiponectin concentrations (33530 ± 9744 vs. 23330 ± 7863 ng/mL, p = 0.002. Percentage haemoglobin A1C (4.0 ± 0.3 vs. 6.0 ± 1.4, p = 0.002 also increased in the intervention group. Conclusions Our findings indicate that when exposed to a high sugar high fat diet, young adult male baboons develop increased body fat and triglyceride concentrations, altered adipokine concentrations, and evidence of altered glucose metabolism. Our findings are in keeping with observations in humans and further demonstrate the potential utility of this highly clinically-relevant animal model for studying diet-induced metabolic dysregulation.

  5. A Wideband High-Gain Dual-Polarized Slot Array Patch Antenna for WiMAX Applications in 5.8 GHz

    Directory of Open Access Journals (Sweden)

    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.

  6. 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

    Directory of Open Access Journals (Sweden)

    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.

  7. Amorphous silicon germanium carbide photo sensitive bipolar junction transistor with a base-contact and a continuous tunable high current gain

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Amorphous silicon germanium carbide photo sensitive bipolar junction transistor with a base-contact and a continuous tunable high current gain

    International Nuclear Information System (INIS)

    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

  9. A C-band 55%PAE high gain two-stage power amplifier based on AlGaN/GaN HEMT

    Institute of Scientific and Technical Information of China (English)

    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.

  10. Contradictions between the Virtual and Physical High School Classroom: A Third-Generation Activity Theory Perspective

    Science.gov (United States)

    Murphy, Elizabeth; Manzanares, Maria A. Rodriguez

    2008-01-01

    This paper uses a third-generation Activity Theory perspective to gain insight into the contradictions between the activity systems of the physical and virtual high school classroom from the perspective of teachers who had transitioned from one system to the other. Data collection relied on semi-structured interviews conducted with e-teachers as…

  11. Effect of betulin-containing extract from birch tree bark on α-amylase activity in vitro and on weight gain of broiler chickens in vivo.

    Science.gov (United States)

    Ilyina, Anna; Arredondo-Valdés, Roberto; Farkhutdinov, Salavat; Segura-Ceniceros, Elda Patricia; Martínez-Hernández, José Luis; Zaynullin, Radik; Kunakova, Rayhana

    2014-03-01

    In vitro effect of betulin-containing extract from Betula pendula Roth. bark on alpha-amylase activity was studied, the kinetic mechanism of interaction was proposed and in vivo effect of betulin-containing extract on weight gain and meat quality of broiler chickens was evaluated. The highest level of inhibitory activity (20%) was detected in extract concentration of 1,000 mg/L. Increased extract concentration did not lead to increased enzyme inhibition. Using Dixon and Cornish-Bowden coordinates, the competitive mechanism of inhibition was demonstrated. Calculated kinetic parameters were: Km equal to 0.6 mg/mL, Vmax equal to 2.6 and 2.1 mM/min from Lineweaver-Burk and Dixon coordinates, respectively and Ki equal to 3,670 ± 230 mg/mL. The partial inhibition of enzyme indicates the existence of low concentration of active inhibitory form, which reaches saturation level with increased extract concentration in applied suspension. Therefore, Ki has an apparent constant character. This partial inhibition of amylase activity observed in in vitro assay did not affect weight gain and meat quality of broiler chickens during in vivo assay. Rather, the tendency to increase the weight of edible parts and muscles compared to diet without additive suggests that the extract may be a potential food additive in poultry farming. Additionally, it could be a source for further pharmaceutical and pharmacological research.

  12. Auto-digital gain balancing: a new detection scheme for high-speed chemical species tomography of minor constituents

    International Nuclear Information System (INIS)

    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

  13. Auto-digital gain balancing: a new detection scheme for high-speed chemical species tomography of minor constituents

    Science.gov (United States)

    Pal, Sandip; McCann, Hugh

    2011-11-01

    In many dynamic gas-phase reaction processes, there is great interest to measure the distribution of minor constituents, i.e. 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.

  14. Gaining Insights from a Case Study of High School Student Performance in Dual-Credit College Chemistry Courses

    Science.gov (United States)

    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…

  15. Vitrification of high active waste

    International Nuclear Information System (INIS)

    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)

  16. Gain-of-function STAT1 mutations impair STAT3 activity in patients with chronic mucocutaneous candidiasis (CMC)

    NARCIS (Netherlands)

    Zheng, J.; Veerdonk, F.L. van de; Crossland, K.L.; Smeekens, S.P.; Chan, C.M.; Shehri, T. Al; Abinun, M.; Gennery, A.R.; Mann, J.; Lendrem, D.W.; Netea, M.G.; Rowan, A.D.; Lilic, D.

    2015-01-01

    Signal transducer and activator of transcription 3 (STAT3) triggered production of Th-17 cytokines mediates protective immunity against fungi. Mutations affecting the STAT3/interleukin 17 (IL-17) pathway cause selective susceptibility to fungal (Candida) infections, a hallmark of chronic mucocutaneo

  17. Remembering with gains and losses: effects of monetary reward and punishment on successful encoding activation of source memories.

    Science.gov (United States)

    Shigemune, Yayoi; Tsukiura, Takashi; Kambara, Toshimune; Kawashima, Ryuta

    2014-05-01

    The motivation of getting rewards or avoiding punishments reinforces learning behaviors. Although the neural mechanisms underlying the effect of rewards on episodic memory have been demonstrated, there is little evidence of the effect of punishments on this memory. Our functional magnetic resonance imaging (fMRI) study investigated the effects of monetary rewards and punishments on activation during the encoding of source memories. During encoding, participants memorized words (item) and locations of presented words (source) under 3 conditions (Reward, Punishment, and Control). During retrieval, participants retrieved item and source memories of the words and were rewarded or penalized according to their performance. Source memories encoded with rewards or punishments were remembered better than those without such encoding. fMRI data demonstrated that the ventral tegmental area and substantia nigra and nucleus accumbens activations reflected both the processes of reward and punishment, whereas insular activation increased as a linear function of punishment. Activation in the hippocampus and parahippocampal cortex predicted subsequent retrieval success of source memories. Additionally, correlations between these reward/punishment-related regions and the hippocampus were significant. The successful encoding of source memories could be enhanced by punishments and rewards, and interactions between reward/punishment-related regions and memory-related regions could contribute to memory enhancement by reward and/or punishment.

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

    Directory of Open Access Journals (Sweden)

    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. Three Months of High-Fructose Feeding Fails to Induce Excessive Weight Gain or Leptin Resistance in Mice

    OpenAIRE

    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...

  20. Ultra-thin single-layer transparent geometrical phase gradient metasurface and its application to high-gain circularly-polarized lens antenna

    Science.gov (United States)

    Li, Tang-Jing; Liang, Jian-Gang; Li, Hai-Peng; Liu, Ya-Qiao

    2016-09-01

    A new method to design an ultra-thin high-gain circularly-polarized antenna system with high efficiency is proposed based on the geometrical phase gradient metasurface (GPGM). With an accuracy control of the transmission phase and also the high transmission amplitude, the GPGM is capable of manipulating an electromagnetic wave arbitrarily. A focusing transmission lens working at Ku band is well optimized with the F/D of 0.32. A good focusing effect is demonstrated clearly by theoretical calculation and electromagnetic simulation. For further application, an ultra-thin single-layer transmissive lens antenna based on the proposed focusing metasurface operating at 13 GHz is implemented and launched by an original patch antenna from the perspective of high integration, simple structure, and low cost. Numerical and experimental results coincide well, indicating the advantages of the antenna system, such as a high gain of 17.6 dB, the axis ratio better than 2 dB, a high aperture efficiency of 41%, and also a simple fabrication process based on the convenient print circuit board technology. The good performance of the proposed antenna indicates promising applications in portable communication systems. Project supported by the National Natural Science Foundation of China (Grant No. 61372034).

  1. Ultra-thin single-layer transparent geometrical phase gradient metasurface and its application to high-gain circularly-polarized lens antenna

    Science.gov (United States)

    Li, Tang-Jing; Liang, Jian-Gang; Li, Hai-Peng; Liu, Ya-Qiao

    2016-09-01

    A new method to design an ultra-thin high-gain circularly-polarized antenna system with high efficiency is proposed based on the geometrical phase gradient metasurface (GPGM). With an accuracy control of the transmission phase and also the high transmission amplitude, the GPGM is capable of manipulating an electromagnetic wave arbitrarily. A focusing transmission lens working at Ku band is well optimized with the F/D of 0.32. A good focusing effect is demonstrated clearly by theoretical calculation and electromagnetic simulation. For further application, an ultra-thin single-layer transmissive lens antenna based on the proposed focusing metasurface operating at 13 GHz is implemented and launched by an original patch antenna from the perspective of high integration, simple structure, and low cost. Numerical and experimental results coincide well, indicating the advantages of the antenna system, such as a high gain of 17.6 dB, the axis ratio better than 2 dB, a high aperture efficiency of 41%, and also a simple fabrication process based on the convenient print circuit board technology. The good performance of the proposed antenna indicates promising applications in portable communication systems. Project supported by the National Natural Science Foundation of China (Grant No. 61372034).

  2. High exposure hardware removal activity readiness evaluation

    International Nuclear Information System (INIS)

    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. A High-Gain Three-Port Power Converter with Fuel Cell, Battery Sources and Stacked Output for Hybrid Electric Vehicles and DC-Microgrids

    OpenAIRE

    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...

  4. Gain-of-function analogs of the pore-forming peptide melittin selected by orthogonal high-throughput screening

    OpenAIRE

    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...

  5. Influence of RZ and NRZ signal format on the high-speed performance of gain-clamped semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    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....

  6. High signal-to-noise ratio sensing with Shack–Hartmann wavefront sensor based on auto gain control of electron multiplying CCD

    Science.gov (United States)

    Zhu, Zhao-Yi; Li, Da-Yu; Hu, Li-Fa; Mu, Quan-Quan; Yang, Cheng-Liang; Cao, Zhao-Liang; Xuan, Li

    2016-09-01

    High signal-to-noise ratio can be achieved with the electron multiplying charge-coupled-device (EMCCD) applied in the Shack–Hartmann wavefront sensor (S–H WFS) in adaptive optics (AO). However, when the brightness of the target changes in a large scale, the fixed electron multiplying (EM) gain will not be suited to the sensing limitation. Therefore an auto-gain-control method based on the brightness of light-spots array in S–H WFS is proposed in this paper. The control value is the average of the maximum signals of every light spot in an array, which has been demonstrated to be kept stable even under the influence of some noise and turbulence, and sensitive enough to the change of target brightness. A goal value is needed in the control process and it is predetermined based on the characters of EMCCD. Simulations and experiments have demonstrated that this auto-gain-control method is valid and robust, the sensing SNR reaches the maximum for the corresponding signal level, and especially is greatly improved for those dim targets from 6 to 4 magnitude in the visual band. Project supported by the National Natural Science Foundation of China (Grant Nos. 11174274, 61205021, and 61405194) and the State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences.

  7. 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

    Institute of Scientific and Technical Information of China (English)

    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.

  8. 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

    Directory of Open Access Journals (Sweden)

    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

  9. Coupled Isothermal Continuous Preferential Crystallization (CIC-PC) – A Novel Promising Technology for Gaining Pure Enantiomers with High Productivity

    OpenAIRE

    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...

  10. A gain-coefficient switched Alexandrite laser

    NARCIS (Netherlands)

    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

  11. JUNGFRAU 0.2: prototype characterization of a gain-switching, high dynamic range imaging system for photon science at SwissFEL and synchrotrons

    Science.gov (United States)

    Jungmann-Smith, J. H.; Bergamaschi, A.; Cartier, S.; Dinapoli, R.; Greiffenberg, D.; Johnson, I.; Maliakal, D.; Mezza, D.; Mozzanica, A.; Ruder, Ch; Schaedler, L.; Schmitt, B.; Shi, X.; Tinti, G.

    2014-12-01

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional pixel detector for photon science applications at free electron lasers and synchrotron light sources. It is developed for the SwissFEL currently under construction at the Paul Scherrer Institute, Switzerland. Characteristics of this application-specific integrating circuit readout chip include single photon sensitivity and low noise over a dynamic range of over four orders of magnitude of photon input signal. These characteristics are achieved by a three-fold gain-switching preamplifier in each pixel, which automatically adjusts its gain to the amount of charge deposited on the pixel. The final JUNGFRAU chip comprises 256 × 256 pixels of 75 × 75 μm2 each. Arrays of 2 × 4 chips are bump-bonded to monolithic detector modules of about 4 × 8 cm2. Multi-module systems up to 16 Mpixels are planned for the end stations at SwissFEL. A readout rate in excess of 2 kHz is anticipated, which serves the readout requirements of SwissFEL and enables high count rate synchrotron experiments with a linear count rate capability of > 20 MHz/pixel. Promising characterization results from a 3.6 × 3.6 mm2 prototype (JUNGFRAU 0.2) with fluorescence X-ray, infrared laser and synchrotron irradiation are shown. The results include an electronic noise as low as 100 electrons root-mean-square, which enables single photon detection down to X-ray energies of about 2 keV. Noise below the Poisson fluctuation of the photon number and a linearity error of the pixel response of about 1% are demonstrated. First imaging experiments successfully show automatic gain switching. The edge spread function of the imaging system proves to be comparable in quality to single photon counting hybrid pixel detectors.

  12. High-fat-diet-induced weight gain ameliorates bone loss without exacerbating AβPP processing and cognition in female APP/PS1 mice

    Directory of Open Access Journals (Sweden)

    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.

  13. Design of wideband high-gain circularly polarized Vivaldi antenna array%高增益宽带圆极化Vivaldi天线阵的设计

    Institute of Scientific and Technical Information of China (English)

    许唐红; 张弘; 王东; 朱海涛; 兰敏

    2013-01-01

    提出了一种由新型Vivaldi天线单元构成的2×2十字交叉圆极化天线阵.Vivaldi天线单元采用边缘渐变对拓的锯齿结构,提高了天线在4.7~7.0 GHz频带内的增益,其反射系数低于-10 dB的带宽为2.4~11.0 GHz,具有超宽带线极化特性.圆极化天线阵测量结果显示,在4.5~7.0 GHz频带范围内,其轴比均低于3 dB,且整个频带范围内增益达11~13 dBi.%A circularly polarized (CP) crossed antenna array with 2X2 elements based on a novel antipodal Vivaldi antenna is proposed. The Vivaldi antenna with tapering serrated structure at the edges, which is a ultra-wideband (UWB) linearly polarized antenna, has a high gain at 4. 7-7. 0 GHz, and a wide impedance bandwidth of 2. 4-11. 0 GHz when the reflection coefficient is smaller than -10 dB. The measured data of the antenna array show that the axial ratio is lower than 3 dB between 4. 5 GHz and 7. 0 GHz. A high antenna gain from 11 dBi to 13 dBi is also achieved at the whole bandwidth of the array. The proposed antenna element and array both own UWB and high-gain characteristics.

  14. Impact of Korean pine nut oil on weight gain and immune responses in high-fat diet-induced obese mice

    OpenAIRE

    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 ...

  15. High effective silica fume alkali activator

    Indian Academy of Sciences (India)

    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. Co-regulation analysis of closely linked genes identifies a highly recurrent gain on chromosome 17q25.3 in prostate cancer

    International Nuclear Information System (INIS)

    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

  17. Co-regulation analysis of closely linked genes identifies a highly recurrent gain on chromosome 17q25.3 in prostate cancer

    Directory of Open Access Journals (Sweden)

    Martínez-A Carlos

    2008-10-01

    Full Text Available Abstract Background 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. Methods 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. Results 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. Conclusion 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

  18. Strongly asymmetric waveguide laser diodes for high brightness picosecond optical pulses generation by gain switching at GHz repetition rates

    International Nuclear Information System (INIS)

    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)

  19. Mechanical design, materials selection, fabrication and assembly of ultraclean, high-gain Nd: glass disk laser amplifiers

    International Nuclear Information System (INIS)

    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

  20. Multipolar, time-dynamical model for the loss compensation and lasing of a spherical plasmonic nanoparticle spaser immersed in an active gain medium

    Science.gov (United States)

    Veltri, Alessandro; Chipouline, Arkadi; Aradian, Ashod

    2016-09-01

    The plasmonic response of a metal nanoparticle in the presence of surrounding gain elements is studied, using a space and time-dependent model, which integrates a quantum formalism to describe the gain and a classical treatment for the metal. Our model fully takes into account the influence of the system geometry (nanosphere) and offers for the first time, the possibility to describe the temporal evolution of the fields and the coupling among the multipolar modes of the particle. We calculate the lasing threshold value for all multipoles of the spaser, and demonstrate that the dipolar one is lowest. The onset of the lasing instability, in the linear regime, is then studied both with and without external field forcing. We also study the behaviour of the system below the lasing threshold, with the external field, demonstrating the existence of an amplification regime where the nanoparticle’s plasmon is strongly enhanced as the threshold is approached. Finally, a qualitative discussion is provided on later, non-linear stages of the dynamics and the approach to the steady-state of the spaser; in particular, it is shown that, for the considered geometry, the spasing is necessarily multi-modal and multipolar modes are always activated.

  1. Experimental studies of high order soliton compression effect and gain characteristics in femtosecond laser pulses Er3+-doped fiber amplifier

    Institute of Scientific and Technical Information of China (English)

    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.

  2. Low Noise Figure, High Gain Single LNA Cascaded with Cascoded LNA Amplifiers using Optimized Inductive Drain Feedback for Direct Conversion RF Front-end Receiver at Wireless Application

    Directory of Open Access Journals (Sweden)

    K. Pongot

    2014-04-01

    Full Text Available This study presents a design of low noise figure, high gain LNA at 5.8 GHz with cascaded and cascoded techniques using inductive drain feedback that is applicable for the WiMAX 802.16 standard. The amplifier uses Pseudomorphic High Electron Mobility Transistor FHX76LP super HEMT low noise FET. The Ansoft Designer SV as an Electromagnetic (EM simulator was used during the design process. The LNA was designed using the inductive drain feedback, inductive generation to the source and the T-network as a matching technique was used at the input and output terminal. The cascaded and cascoded Low Noise Amplifier (LNA produced a gain (S21 of 43.94 dB and the Noise Figure (NF of 0.61 dB. The input reflection (S11, output reflection (S22 and return loss (S12 are -10.65, -20.02 and -52.23 dB, respectively. The measured 3 dB bandwidth of 1.24 GHz has been achieved. The input sensitivity is -84 dBm exceeded the standards required by IEEE 802.16 has been observed.

  3. Low Noise Figure and High Gain Single Stage Cascoded LNA Amplifier With Optimized Inductive Drain Feedback for WiMAX Application

    Directory of Open Access Journals (Sweden)

    Othman A.R

    2013-06-01

    Full Text Available This project presents a low noise and high gain cascoded LNA amplifier for direct conversion RF front end receiver architecture, which operates at 5.8 GHz unlicensed band. The LNA used Transistor FHX76LP superHEMT low noise FET. This LNA was designed and used inductive feedback and T- matching network consisting of lump reactive at the input and output of the LNA circuit. A single cascoded LNA design was built to meet the standard of IEEE 802.16. The cascoded LNA produced low noise figure of 0.83 dB with high gain of 26.26 dB. The S-parameter for the input reflection S11, output reflection S22, and return loss S12 are of -11.05 dB, -10.5 dB and -30.92 dB respectively. The bandwidth measured is 1.56 GHz, while the input sensitivity is -82.6 dBm which is compliant WiMAX standards. The single stage LNA amplifier simulated using Ansoft Designer SV.

  4. Gut microbiota Modulated by Probiotics and Garcinia cambogia Extract Correlate with Weight Gain and Adipocyte Sizes in High Fat-Fed Mice

    Science.gov (United States)

    Heo, Jaeyoung; Seo, Minseok; Park, Hwanhee; Lee, Woon Kyu; Guan, Le Luo; Yoon, Joon; Caetano-Anolles, Kelsey; Ahn, Hyeonju; Kim, Se-Young; Kang, Yoon-Mo; Cho, Seoae; Kim, Heebal

    2016-01-01

    Results of recent studies on gut microbiota have suggested that obesogenic bacteria exacerbate obesity and metabolic dysfunction in the host when fed a high fat diet (HFD). In order to explore obesity-associated bacterial candidates and their response to diet, the composition of faecal bacterial communities was investigated by analyzing 16S rRNA gene sequences in mice. Dietary intervention with probiotics and Garcinia cambogia extract attenuated weight gain and adipocyte size in HFD-fed mice. To identify obesity-causative microbiota, two statistical analyses were performed. Forty-eight bacterial species were found to overlap between the two analyses, indicating the commonly identified species as diet-driven and obesity-associated, which would make them strong candidates for host-microbiome interaction on obesity. Finally, correlation based network analysis between diet, microbe, and host revealed that Clostridium aminophilum, a hyper-ammonia-producing bacterium, was highly correlated with obesity phenotypes and other associated bacteria, and shown to be suppressed by the combination of probiotics and Garcinia cambogia extract. Results of the present study suggest that probiotics and Garcinia cambogia extract alleviate weight gain and adiposity, in part via differentially modulating the composition of gut microbiota in HFD fed mice. PMID:27658722

  5. A High-Gain Three-Port Power Converter with Fuel Cell, Battery Sources and Stacked Output for Hybrid Electric Vehicles and DC-Microgrids

    Directory of Open Access Journals (Sweden)

    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.

  6. Chrysobalanus icaco L. Leaves Normalizes Insulin Sensitivity and Blood Glucose and Inhibits Weight Gain in High-Fat Diet-Induced Obese Mice.

    Science.gov (United States)

    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

  7. The Study of Electromagnetic Wave Propogation in Photonic Crystals Via Planewave Based Transfer (Scattering) Matrix Method with Active Gain Material Applications

    Energy Technology Data Exchange (ETDEWEB)

    LI, Ming [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    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.

  8. A flexible and high-performance bidirectional optical amplifier with all optical gain control using ASE noise path through multi-port circulators

    Institute of Scientific and Technical Information of China (English)

    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.

  9. A flexible and high-performance bidirectional optical amplifier with all-optical gain control using ASE noise path through multi-port circulators

    Institute of Scientific and Technical Information of China (English)

    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. Effects on weight gain and gut microbiota in rats given bacterial supplements and a high-energy-dense diet from fetal life through to 6 months of age.

    Science.gov (United States)

    Karlsson, Caroline L J; Molin, Göran; Fåk, Frida; Johansson Hagslätt, Marie-Louise; Jakesevic, Maja; Håkansson, Åsa; Jeppsson, Bengt; Weström, Björn; Ahrné, Siv

    2011-09-01

    The aim of the present study was to assess the long-term effects of a high-energy-dense diet, supplemented with Lactobacillus plantarum (Lp) or Escherichia coli (Ec), on weight gain, fattening and the gut microbiota in rats. Since the mother's dietary habits can influence offspring physiology, dietary regimens started with the dams at pregnancy and throughout lactation and continued with the offspring for 6 months. The weight gain of group Lp was lower than that of groups C (control) and Ec (P = 0·086). More retroperitoneal adipose tissue (P = 0·030) and higher plasma leptin (P = 0·035) were observed in group Ec compared with group Lp. The viable count of Enterobacteriaceae was higher in group Ec than in group Lp (P = 0·019), and when all animals were compared, Enterobacteriaceae correlated positively with body weight (r 0·428, P = 0·029). Bacterial diversity was lower in group Ec than in groups C (P ≤ 0·05) and Lp (P ≤ 0·05). Firmicutes, Bacteroidetes and Verrucomicrobia dominated in all groups, but Bacteroidetes were more prevalent in group C than in groups Lp (P = 0·036) and Ec (P = 0·056). The same five bacterial families dominated the microbiota of groups Ec and C, and four of these were also present in group Lp. The other five families dominating in group Lp were not found in any of the other groups. Multivariate data analysis pointed in the same directions as the univariate statistics. The present results suggest that supplementation of L. plantarum or E. coli can have long-term effects on the composition of the intestinal microbiota, as well as on weight gain and fattening.

  11. High d(+)-fructose diet adversely affects testicular weight gain in weaning rats─protection by moderate d(+)-glucose diet.

    Science.gov (United States)

    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

  12. Challenges for the Adaptive Gain Integrating Pixel Detector (AGIPD) design due to the high intensity photon radiation environment at the European XFEL

    CERN Document Server

    Becker, J; Göttlicher, P; Graafsma, H; Hirsemann, H; Jack, S; Klyuev, A; Marras, S Lange A; Trunk, U; Klanner, R; Schwandt, J; Zhang, J; Dinapoli, R; Greiffenberg, D; Henrich, B; Mozzanica, A; Schmitt, B; Shi, X; Gronewald, M; Krüger, H

    2013-01-01

    The European X-ray Free Electron Laser (XFEL) is a new research facility currently under construction in Hamburg, Germany. With a pulse length of less than 100 fs and an extremely high luminosity of 27000 flashes per second the European XFEL will have a unique time structure that demands the development of new detectors tailored to the requirements imposed by the experiments while complying with the machine specific operation parameters. The Adaptive Gain Integrating Pixel Detector (AGIPD) is one response to the need for large 2D detectors, able to cope with the 4.5 MHz frame rate, as well as with the high dynamic range needed by XFEL experiments ranging from single photons to more than 10$^4$ 12 keV photons per pixel per pulse. In addition it has to withstand doses of up to 1 GGy over three years.

  13. Whey-reduced weight gain is associated with a temporary growth reduction in young mice fed a high-fat diet

    DEFF Research Database (Denmark)

    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...

  14. 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.

    Science.gov (United States)

    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

  15. Tailoring Directive Gain for High-Contrast, Wide-Viewing-Angle Organic Light-Emitting Diodes Using Speckle Image Holograpy Metasurfaces.

    Science.gov (United States)

    Zhou, Lei; Ou, Qing-Dong; Shen, Su; Zhou, Yun; Fan, Yuan-Yuan; Zhang, Jun; Tang, Jian-Xin

    2016-08-31

    Holography metasurfaces have been used to control the propagation of light to an unprecedented level, exhibiting the immense potential for light steering in organic light-emitting diodes (OLEDs). Here, a new approach to tailoring directive gain for high contrast, wide-viewing-angle OLEDs is proposed by implementing a spcekle image holography (SIH) metasurface. The experimental and theoretical results provide the direct proofs that the SIH metasurface can play very important roles not only in releasing the trapped energy flow insides the devices but also in tailoring the wavefronts to the preferred patterns due to its "regional orientation" k-vectors patterns. The resulting power efficiency and external quantum efficiency of the OLEDs using a SIH metasurface are 1.97 and 1.95 times that of the reference device with a standard architecture. Furthermore, the wavefronts of emitted light are delicately modulated in a polarization-independent manner, yielding 2.5 times higher contrast ratio compared to the reference device. This unique engineered directive gain property is also well-retained for the viewing angles varing from normal to titled ±60° without spectral distortion. These results enrich the understanding of light wavefronts control in OLEDs and highlight its potential application in display as well as light steering for other optoelectronics.

  16. Tailoring Directive Gain for High-Contrast, Wide-Viewing-Angle Organic Light-Emitting Diodes Using Speckle Image Holograpy Metasurfaces.

    Science.gov (United States)

    Zhou, Lei; Ou, Qing-Dong; Shen, Su; Zhou, Yun; Fan, Yuan-Yuan; Zhang, Jun; Tang, Jian-Xin

    2016-08-31

    Holography metasurfaces have been used to control the propagation of light to an unprecedented level, exhibiting the immense potential for light steering in organic light-emitting diodes (OLEDs). Here, a new approach to tailoring directive gain for high contrast, wide-viewing-angle OLEDs is proposed by implementing a spcekle image holography (SIH) metasurface. The experimental and theoretical results provide the direct proofs that the SIH metasurface can play very important roles not only in releasing the trapped energy flow insides the devices but also in tailoring the wavefronts to the preferred patterns due to its "regional orientation" k-vectors patterns. The resulting power efficiency and external quantum efficiency of the OLEDs using a SIH metasurface are 1.97 and 1.95 times that of the reference device with a standard architecture. Furthermore, the wavefronts of emitted light are delicately modulated in a polarization-independent manner, yielding 2.5 times higher contrast ratio compared to the reference device. This unique engineered directive gain property is also well-retained for the viewing angles varing from normal to titled ±60° without spectral distortion. These results enrich the understanding of light wavefronts control in OLEDs and highlight its potential application in display as well as light steering for other optoelectronics. PMID:27525446

  17. High-capacity neutron activation analysis facility

    International Nuclear Information System (INIS)

    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

  18. Gain ranging amplifier

    International Nuclear Information System (INIS)

    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

  19. Enclosure for handling high activity materials

    Energy Technology Data Exchange (ETDEWEB)

    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)

  20. A High Gain Interleaved Coupled-inductor DC/DC Converter%一种高增益交错耦合电感直流变换器

    Institute of Scientific and Technical Information of China (English)

    胡雪峰; 龚春英; 陈杰; 王琳

    2014-01-01

    A novel high step-up interleaved dc-dc converter topology with two coupled-inductors is presented for low input voltage and high input current applications, such as photovoltaic and fuel cell generation systems. In the proposed converter, the primary currents of two coupled-inductors are interleaved in parallel at input, which reduces the input current ripple. The secondary sides of two coupled-inductors are connected in series with a capacitor for a double voltage cell to improve the voltage gain further. Moreover, this structure can also reduce the voltage/current stresses of active switches and diodes. The leakage energy can also be recycled by the two output capacitors, which are charged interleaving in parallel and discharged in series. In addition, the reverse-recovery problems of diodes are alleviated significantly by the leakage inductance. The operating principle and the steady-state characteristics are discussed in detail to show the merits of the presented converter and the corresponding model is also derived. Finally, a rating prototype system is constructed to verify the effectiveness of the proposed converter.%提出一种高增益交错耦合电感直流-直流升压变换器,适用于低输入电压、高输入电流的低压可再生能源发电系统应用场合,如光伏/燃料电池发电系统。该变换器在输入端把两个耦合电感的原边电流进行交错并联,减小了输入电流和输出电压纹波;两个耦合电感的副边串联后再与一电容相结合组成倍压单元,进一步提高变换器的电压增益。该电路结构中,使用两个交错串联的输出电容,它们既能回收利用耦合电感的漏感能量,又能钳位开关管的漏源电压,减小开关管电压应力,因此,有利于选择低导通电阻、高性能的开关器件以进一步减小功率管的开关和导通损耗。另外,耦合电感的漏感可使主开关管零电流开通,同时漏感也能控制二极管

  1. Gain-of-function mutations in the Toll-like Receptor pathway: TPL2-mediated ERK1/ERK2 MAPK activation, a path to tumorigenesis in lymphoid neoplasms?

    Directory of Open Access Journals (Sweden)

    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

  2. ApoE4-Driven Accumulation of Intraneuronal Oligomerized Aβ42 following Activation of the Amyloid Cascade In Vivo Is Mediated by a Gain of Function

    Directory of Open Access Journals (Sweden)

    Lia Zepa

    2011-01-01

    Full Text Available Activating the amyloid cascade by inhibiting the Aβ-degrading enzyme neprilysin in targeted replacement mice, which express either apoE4 or apoE3, results in the specific accumulation of oligomerized Aβ42 in hippocampal CA1 neurons of the apoE4 mice. We presently investigated the extent to which the apoE4-driven accumulation of Aβ42 and the resulting mitochondrial pathology are due to either gain or loss of function. This revealed that inhibition of neprilysin for one week triggers the accumulation of Aβ42 in hippocampal CA1 neurons of the apoE4 mice but not of either the corresponding apoE3 mice or apoE-deficient mice. At 10 days, Aβ42 also accumulated in the CA1 neurons of the apoE-deficient mice but not in those of the apoE3 mice. Mitochondrial pathology, which in the apoE4 mice is an early pathological consequence following inhibition of neprilyisn, also occurs in the apoE-deficient but not in the apoE3 mice and the magnitude of this effect correlates with the levels of accumulated Aβ42 and oligomerized Aβ42 in these mice. These findings suggest that the rate-limiting step in the pathological effects of apoE4 on CA1 neurons is the accumulation of intracellular oligomerized Aβ42 which is mediated via a gain of function property of apoE4.

  3. Generating Isolated Terawatt-Attosecond X-ray Pulses via a Chirped Laser Enhanced High-Gain Free-electron Laser

    CERN Document Server

    Wang, Zhen; Zhao, Zhentang

    2016-01-01

    A feasible method is proposed to generate isolated attosecond terawatt x-ray radiation pulses in high-gain free-electron lasers. In the proposed scheme, a frequency chirped laser pulse is employed to generate a gradually-varied spacing current enhancement of the electron beam and a series of spatiotemporal shifters are applied between the undulator sections to amplify a chosen ultra-short radiation pulse from self-amplified spontaneous emission. Three-dimensional start-to-end simulations have been carried out and the calculation results demonstrated that 0.15 nm x-ray pulses with peak power over 1TW and duration of several tens of attoseconds could be achieved by using the proposed technique.

  4. High active waste (HAW) data report

    International Nuclear Information System (INIS)

    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

    Institute of Scientific and Technical Information of China (English)

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

    International Nuclear Information System (INIS)

    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

  7. 一种新型的高增益低剖面天线%A Novel Low-Profile High-Gain Antenna

    Institute of Scientific and Technical Information of China (English)

    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.

  8. Achieving high-resolution soft-tissue imaging with cone-beam CT: a two-pronged approach for modulation of x-ray fluence and detector gain

    Science.gov (United States)

    Graham, S. A.; Siewerdsen, J. H.; Moseley, D. J.; Keller, H.; Shkumat, N. A.; Jaffray, D. A.

    2005-04-01

    Cone-beam computed tomography (CBCT) presents a highly promising and challenging advanced application of flat-panel detectors (FPDs). The great advantage of this adaptable technology is in the potential for sub-mm 3D spatial resolution in combination with soft-tissue detectability. While the former is achieved naturally by CBCT systems incorporating modern FPD designs (e.g., 200 - 400 um pixel pitch), the latter presents a significant challenge due to limitations in FPD dynamic range, large field of view, and elevated levels of x-ray scatter in typical CBCT configurations. We are investigating a two-pronged strategy to maximizing soft-tissue detectability in CBCT: 1) front-end solutions, including novel beam modulation designs (viz., spatially varying compensators) that alleviate detector dynamic range requirements, reduce x-ray scatter, and better distribute imaging dose in a manner suited to soft-tissue visualization throughout the field of view; and 2) back-end solutions, including implementation of an advanced FPD design (Varian PaxScan 4030CB) that features dual-gain and dynamic gain switching that effectively extends detector dynamic range to 18 bits. These strategies are explored quantitatively on CBCT imaging platforms developed in our laboratory, including a dedicated CBCT bench and a mobile isocentric C-arm (Siemens PowerMobil). Pre-clinical evaluation of improved soft-tissue visibility was carried out in phantom and patient imaging with the C-arm device. Incorporation of these strategies begin to reveal the full potential of CBCT for soft-tissue visualization, an essential step in realizing broad utility of this adaptable technology for diagnostic and image-guided procedures.

  9. Activity-based Costing (ABC and Activity-based Management(ABMImplementation – Is This the Solution for Organizations to Gain Profitability?

    Directory of Open Access Journals (Sweden)

    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.

  10. Production of high specific activity silicon-32

    International Nuclear Information System (INIS)

    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

  11. A high multivitamin diet fed to Wistar rat dams during pregnancy increases maternal weight gain later in life and alters homeostatic, hedonic and peripheral regulatory systems of energy balance.

    Science.gov (United States)

    Pannia, Emanuela; Cho, Clara E; Kubant, Ruslan; Sánchez-Hernández, Diana; Huot, Pedro S P; Chatterjee, Diptendu; Fleming, Alison; Anderson, G Harvey

    2015-02-01

    High multivitamin (10-fold, HV) and high folic acid (Fol) diets fed to pregnant Wistar rats increase body weight and characteristics of the metabolic syndrome in their offspring. Our objective was to determine the effects of a HV maternal diet on dams and whether methyl vitamins contribute to these effects. Pregnant Wistar rats were fed AIN-93G diets containing either (1) recommended multivitamins (RV, control), (2) HV, (3) HV with recommended Fol (HVRF; 1-fold Fol), or (4) RV with high methyl group vitamins (HMethyl; 10-fold Fol, vitamin B12 and B6). All groups were fed a RV diet during lactation until weaning and a RV high fat (HF; 60% fat) diet for 16 weeks post-weaning. The HV, HVRF and HMethyl diet fed dams gained 45% more weight from 2 to 15 weeks post-weaning and their weight gain (WG) was positively associated with cumulative post-weaning food intake (FI). However, only HV dams had a reduced preference for a sucrose solution, lower mesolimbic dopamine (DA) turnover in the nucleus accumbens (NAc), and higher expression of several genes involved in FI regulation in the arcuate nucleus of the hypothalamus (ARC). Energy conserving peroxisome proliferator-activated receptor (Ppar)-γ in adipose and -α in liver was also greater in these dams consistent with their WG. In conclusion, HV, HVRF and HMethyl maternal diets exacerbate maternal WG when dams are exposed to a HF diet post-weaning. However, the diets differed in their effects on central and peripheral regulatory systems of energy balance. PMID:25264184

  12. Should I Gain Weight?

    Science.gov (United States)

    ... 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 ...

  13. Health gain versus equity.

    Science.gov (United States)

    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

  14. 带开关电容网络的交错并联高增益Boost变换器%Interleaved High Gain Boost Converter With Switched Capacitor Network

    Institute of Scientific and Technical Information of China (English)

    陆治国; 郑路遥; 马召鼎; 刘捷丰; 秦煜森

    2012-01-01

    提出了一种新颖的带开关电容网络的交错并联高增益Boost变换器,对其工作原理和特性进行了详细分析。变换器的拓扑在传统两相交错并联Boost变换器的基础上增加了一个二极管和两个电容,并进行改进,构成了开关电容网络。与传统两相交错并联Boost变换器相比,新拓扑不仅输入电流纹波减小,而且在相同的占空比下实现了更高的电压增益,开关器件的电压应力得以减小。因此,新拓扑非常适合应用于低压输入、高压输出的场合,如燃料电池、光伏发电等系统。最后,通过实验验证了理论分析的正确性。%A novel interleaved high gain Boost converter with switched capacitor network is proposed in this paper. Operation principle and property of this converter are analyzed. Based on the traditional two phase interleaved Boost converter, a diode and two capacitors are added, and forms into a switched capacitor network. Compared with the traditional two phase interleaved Boost converter, the ripple of the input ripple current is still low, but the voltage gain is higher and the voltage stresses of the switches are reduced. Consequently, the new topology is very suitable for the application, such as the fuel cell power system and photovoltaic system, in which it has low input voltage but high output voltage. Finally, the experiment is built to verify the theoretical analysis.

  15. Rice koji reduced body weight gain, fat accumulation, and blood glucose level in high-fat diet-induced obese mice

    Directory of Open Access Journals (Sweden)

    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.

  16. Tetrahydro iso-alpha acids from hops improve glucose homeostasis and reduce body weight gain and metabolic endotoxemia in high-fat diet-fed mice.

    Directory of Open Access Journals (Sweden)

    Amandine Everard

    Full Text Available Obesity and related metabolic disorders such as insulin resistance and type 2 diabetes are associated with a low-grade inflammatory state possibly through changes in gut microbiota composition and the development of higher plasma lipopolysaccharide (LPS levels, i.e. metabolic endotoxemia. Various phytochemical compounds have been investigated as potential tools to regulate these metabolic features. Humulus lupulus L. (hops contains several classes of compounds with anti-inflammatory potential. Recent evidence suggests that hops-derived compounds positively impact adipocyte metabolism and glucose tolerance in obese and diabetic rodents via undefined mechanisms. In this study, we found that administration of tetrahydro iso-alpha acids (termed META060 to high-fat diet (HFD-fed obese and diabetic mice for 8 weeks reduced body weight gain, the development of fat mass, glucose intolerance, and fasted hyperinsulinemia, and normalized insulin sensitivity markers. This was associated with reduced portal plasma LPS levels, gut permeability, and higher intestinal tight junction proteins Zonula occludens-1 and occludin. Moreover, META060 treatment increased the plasma level of the anti-inflammatory cytokine interleukin-10 and decreased the plasma level of the pro-inflammatory cytokine granulocyte colony-stimulating factor. In conclusion, this research allows us to decipher a novel mechanism contributing to the positive effects of META060 treatment, and supports the need to investigate such compounds in obese and type 2 diabetic patients.

  17. 一种高增益缝隙定向天线设计%A high-gain slot directional antenna design

    Institute of Scientific and Technical Information of China (English)

    张长慧; 董胜; 赵宪臣

    2012-01-01

    In order to achieve a high-gain and low sidelobe antenna,a substrate integrated waveguide antenna array is designed. Choke Grooves are added between two neighboring radiation waveguides. Compared with traditional SIW slot antenna array, this improvement can greatly extend the operational bandwidth. SIW slot antenna array which meets both low side lobe and return loss requirement in desired bandwidth (8%)The experiments show that this antenna has good performance, and achieve the design requirement.%为实现高增益低旁瓣的定向天线,设计了一种采用介质基片集成波导实现缝隙天线阵,并在辐射缝隙两边增加扼流槽.与传统的介质基片集成波导相比,大幅增加了带宽。最后实现了一介质基片集成波导天线阵,其带宽增加了8%。实际测试表明该天线具有高增益,低旁瓣,达到了设计要求。

  18. High energy activation data library (HEAD-2009)

    International Nuclear Information System (INIS)

    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.

  19. 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

    Science.gov (United States)

    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

  20. Proteasome inhibitors and IMiDs can overcome some high-risk cytogenetics in multiple myeloma but not gain 1q21

    DEFF Research Database (Denmark)

    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...

  1. A low-power high-performance configurable auto-gain control loop for a digital hearing aid SoC

    Science.gov (United States)

    Chengying, Chen; Hainan, Liu; Yong, Hei; Jun, Fan; Xiaoyu, Hu

    2013-10-01

    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.

  2. High gain L-band erbium-doped fiber amplifier with two-stage double-pass configuration

    Indian Academy of Sciences (India)

    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.

  3. Concrete with Highly Active Rice Husk Ash

    Institute of Scientific and Technical Information of China (English)

    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.

  4. Active interrogation of highly enriched uranium

    Science.gov (United States)

    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

  5. Relational Information Gain

    DEFF Research Database (Denmark)

    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......-to-specific search algorithms such as FOIL, it yields an efficient and competitive algorithm in terms of predictive accuracy and compactness of the learned theory. In conjunction with the decision tree learner TILDE, it offers a beneficial alternative to lookahead, achieving similar performance while significantly...

  6. Receiver Gain Modulation Circuit

    Science.gov (United States)

    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

  7. Gaining Mindshare and Timeshare : Marketing Public Libraries

    OpenAIRE

    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.

  8. Photosynthetically active sunlight at high southern latitudes.

    Science.gov (United States)

    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

  9. High performance composites with active stiffness control.

    Science.gov (United States)

    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

  10. High-Throughput Analysis of Enzyme Activities

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Guoxin [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    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

  11. Metabolic Activity of Bacteria at High Pressure

    Science.gov (United States)

    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

  12. 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

    OpenAIRE

    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...

  13. Targeting Binge Eating for the Prevention of Excessive Weight Gain: Interpersonal Psychotherapy for Adolescents at High-Risk for Adult Obesity

    OpenAIRE

    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...

  14. A low-power high-performance configurable auto-gain control loop for a digital hearing aid SoC

    International Nuclear Information System (INIS)

    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)

  15. Selective High Impedance Surface Active Region Loading of Archimedean Spiral Antenna

    OpenAIRE

    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...

  16. 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.

    Directory of Open Access Journals (Sweden)

    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.

  17. Active video games as a tool to prevent excessive weight gain in adolescents : rationale, design and methods of a randomized controlled trial

    OpenAIRE

    Simons, Monique; Chinapaw, Mai J. M.; van de Bovenkamp, Maaike; de Boer, Michiel R.; Jacob C Seidell; 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 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...

  18. Gain Shift Corrections at Chi-Nu

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. The influence of gain nonlinearities on distortion in semiconductor lasers

    Science.gov (United States)

    Lysak, Vladimir V.; Schatz, Richard; Shulika, Aleksey V.; Sukhoivanov, Igor A.; Kjebon, O.

    2004-09-01

    The semiconductor laser is commonly used as a light source in fiber-optical telecommunication systems. In order to send as much information as possible in a short time, it is important that the laser has a large modulation bandwidth, i.e., the turn-on and turn-off time should be as short as possible. In analogue fiber optic systems for transmission of radio or television signals, it is also important that the light from the laser increases linearly with driving current even at high modulation frequencies. Otherwise, the transmitted signal will become distorted. The modulation bandwidth and the modulation distortion are dependent both on the laser structure and the gain characteristics of the active material. One of the most useful approaches for the time-domain description of the response of optoelectronic devices is the so-called "rate equation model," which has been widely used to describe laser performance. Commonly, laser models with simple gain expressions are used for simulation of laser dynamics. In these models the small-signal dynamic parameters like the differential gain and gain saturation parameter are extracted from modulation response measurements. However, we show that in order to correctly calculate distortion, an accurate model of the dependence of gain on carrier density, n, and photon density, s, is needed. Commonly used gain models, fitted to give exactly the same modulation response can give significantly different distortion behavior.

  20. A design of high-gain end-fire antenna based on split-ring resonator structures%一种基于开口谐振环的高增益端射天线设计∗

    Institute of Scientific and Technical Information of China (English)

    刘红喜; 高军; 曹祥玉; 刘艳芳; 张迪; 李思佳

    2015-01-01

    Vivaldi antennas have wide applications in practice due to the ultra-wide band properties;however, their gain and directivity are relatively low. In this paper, a new method is presented to improve the gain and directivity of Vivaldi antennas in a broad band using split-ring resonator (SRR). Based on the peculiar electromagnetic properties of SRR, a novel high-gain SRR-Vivaldi end-fire antenna in C and X bands is designed and fabricated. The size of the antenna is only 0.33λ× 0.33λ× 0.013λ, a significant miniaturization. Equivalent analysis method has been adopted to study the resonance characteristic of an SRR structure. By adding the SRR structures the singular metamaterials in the front of the Vivaldi antenna have an exponential taper slot, and the SRR structures can play a role as a director which has the ability to enhance the antenna’s directivity so that the surface currents will focus on the end-fire direction. The SRR structures have been analyzed, designed, and fabricated, which can be embedded into the original Vivaldi antenna smoothly and compactly. As a result, the gain of the SRR-Vivaldi antenna are enhanced effectively, while the size and bandwidth of the original antenna can be kept, with the reflection coeffcient less than−10 dB from 4 to 13.6 GHz after using SRR. The novel Vivaldi antenna based on the SRR has good features of high gain, high directivity, low return loss and low cross-polarization. Compared to the original Vivaldi antenna, the simulation and measured results demonstrate that the gain of the novel SRR-Vivaldi antenna in C band has been increased by an average value of 75.44% and the half-power beam width has been decreased by 20 degrees in xoy and xoz planes. Meanwhile, the gain has been increased by an average value of 24.46% in X band and the half-power beam width has been decreased by 25 degrees in xoz plane. Testing result of the fabricated antenna demonstrates the reliability of the design. A good agreement between

  1. Active video games as a tool to prevent excessive weight gain in adolescents: Rationale, design and methods of a randomized controlled trial

    NARCIS (Netherlands)

    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

  2. Active video games as a tool to prevent excessive weight gain in adolescents: rationale, design and methods of a randomized controlled trial

    NARCIS (Netherlands)

    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

  3. Active video games as a tool to prevent excessive weight gain in adolescents : rationale, design and methods of a randomized controlled trial

    NARCIS (Netherlands)

    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

  4. 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

    Institute of Scientific and Technical Information of China (English)

    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。

  5. 基于AMC加载的高增益60GHz天线%60GHz High Gain Antenna Based on Loading AMC

    Institute of Scientific and Technical Information of China (English)

    张奇; 朱华; 李秀萍

    2014-01-01

    To solve the problem of improving antenna gain without changing antenna structure, the method of loading AMC (Artificial Magnetic Conductor) is used. An antenna loading ring slot AMC is presented, then the AMC phase is optimized to achieve good performance of the antenna. The loaded antenna is consists of AMC and a 60GHz microstrip patch antenna. The bandwidth of antenna loading AMC is 10GHz (55GHz-65GHz) and the gain is 5.6dBi; Experimental results show that the bandwidth of loaded antenna has no change and the gain increases 2.9dBi, compared to the microstrip patch antenna.%针对如何在不改变天线结构的前提下增大天线增益的问题,采用了AMC(人工磁导体)加载的方法。设计一款圆环缝隙AMC加载的天线,通过对AMC相位的改变来优化天线。设计的加载天线包括AMC和60GHz微带贴片天线,该加载天线拥有10GHz(55GHz-65GHz)的带宽和5.6dBi的增益;实验结果表明,相比没有加载之前的天线,加载天线拥有相同的带宽,其增益提高了2.9dBi。

  6. A novel structure of a high current gain 4H-SiC BJT with a buried layer in the base

    Institute of Scientific and Technical Information of China (English)

    Zhang You-Run; Zhang Bo; Li Zhao-Ji; Deng Xiao-Chuan; Liu Xi-Ling

    2009-01-01

    In this paper,a new structure of a 4H-SiC bipolar junction transistor (BJT) with a buried layer (BL) in the base is presented. The current gain shows an approximately 100% increase compared with that of the conventional structure.This is attributed to the creation of a built-in electric field for the minority carriers to transport in the base which is explained based on 2D device simulations. The optimized design of the buried layer region is also considered by numeric simulations.

  7. Broadband high efficiency active integrated antenna

    OpenAIRE

    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...

  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.

    Science.gov (United States)

    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.

  9. Gaining Relational Competitive Advantages

    DEFF Research Database (Denmark)

    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....

  10. Activation of Plant Immune Responses by a Gain-of-Function Mutation in an Atypical Receptor-Like Kinase1[C][W][OA

    Science.gov (United States)

    Bi, Dongling; Cheng, Yu Ti; Li, Xin; Zhang, Yuelin

    2010-01-01

    Arabidopsis (Arabidopsis thaliana) suppressor of npr1-1, constitutive1 (snc1) contains a gain-of-function mutation in a Toll/interleukin receptor-nucleotide binding site-leucine-rich repeat Resistance (R) protein and it has been a useful tool for dissecting R-protein-mediated immunity. Here we report the identification and characterization of snc4-1D, a semidominant mutant with snc1-like phenotypes. snc4-1D constitutively expresses defense marker genes PR1, PR2, and PDF1.2, and displays enhanced pathogen resistance. Map-based cloning of SNC4 revealed that it encodes an atypical receptor-like kinase with two predicted extracellular glycerophosphoryl diester phosphodiesterase domains. The snc4-1D mutation changes an alanine to threonine in the predicted cytoplasmic kinase domain. Wild-type plants transformed with the mutant snc4-1D gene displayed similar phenotypes as snc4-1D, suggesting that the mutation is a gain-of-function mutation. Epistasis analysis showed that NON-RACE-SPECIFIC DISEASE RESISTANCE1 is required for the snc4-1D mutant phenotypes. In addition, the snc4-1D mutant phenotypes are partially suppressed by knocking out MAP KINASE SUBSTRATE1, a positive defense regulator associated with MAP KINASE4. Furthermore, both the morphology and constitutive pathogen resistance of snc4-1D are partially suppressed by blocking jasmonic acid synthesis, suggesting that jasmonic acid plays an important role in snc4-1D-mediated resistance. Identification of snc4-1D provides us a unique genetic system for analyzing the signal transduction pathways downstream of receptor-like kinases. PMID:20508139

  11. Does previous participation in high-impact training result in residual bone gain in growing girls? One year follow-up of a 9-month jumping intervention.

    Science.gov (United States)

    Kontulainen, S A; Kannus, P A; Pasanen, M E; Sievänen, H T; Heinonen, A O; Oja, P; Vuori, I

    2002-11-01

    The skeletal response to exercise and training on bone is exceptionally good during the growing years. However, it is not known whether the benefit of training on bone is maintained after the training. This 20-month follow-up study assessed the effect of a 9-month jumping intervention on bone gain and physical performance in 99 girls (mean age 12.5 +/- 1.5 years at the beginning of the study) one year after the end of the intervention. Both bone mineral content (BMC), by dual energy X-ray absorptiometry (DXA) at the lumbar spine and proximal femur, and physical performance parameters (standing long jump, leg extension strength, and shuttle run tests) were measured at baseline and at 20 months. A multivariate regression analysis was first used to determine the best predictors of the BMC accrual by time. Analysis showed that age at baseline and square of age, changes in height and weight, and pubertal development into Tanner stages 4 and 5 during the follow-up explained the majority of the BMC gain. Then, the effect of participation in the 9-month exercise intervention on BMC accrual and physical performance was analysed adding this variable (participation: yes/no) into the model. The regression analysis showed that the trainees (N = 50) had 4.9 % (95 % CI, 0.9 % to 8.8 %, p = 0.017) greater BMC increase in the lumbar spine than the controls (N = 49). The mean 20-month BMC increase in the lumbar spine was 28 % (SD 19) in the trainees compared to 22 % (12) increase in the controls. In the proximal femur, the trend was similar but the obtained 2 to 3 % higher BMC accrual in the trainees (compared to that in controls) were statistically insignificant. Among the performance variables, using the same model that best predicted the BMC accrual, the only statistically significant between-groups difference, in favour of the trainees, was the improvement in the standing long jump test (6.4 %, 95 % CI, 2.3 % to 10.4 %, p = 0.002). Improvements in the leg extension strength and

  12. Single crystalline Er{sub 2}O{sub 3}:sapphire films as potentially high-gain amplifiers at telecommunication wavelength

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Gaining and sustaining schistosomiasis control

    DEFF Research Database (Denmark)

    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...

  14. Cash and in-kind transfers lead to excess weight gain in a population of women with a high prevalence of overweight in rural Mexico.

    Science.gov (United States)

    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 <25 kg/m2. Providing households with a considerable amount of unrestricted resources led to excess weight gain in an already overweight population. Research is needed to develop cost-effective behavior change communication strategies to complement cash and in-kind transfer programs such as PAL and to help beneficiaries choose healthy diets that improve the nutritional status of all family members.

  15. Graphene as Gain Medium for Broadband Lasers

    OpenAIRE

    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...

  16. Active noise control for high frequencies

    OpenAIRE

    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...

  17. Sudden gains in psychotherapy

    OpenAIRE

    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...

  18. Gain optimization method of a DQW superluminescent diode with broad multi-state emission

    KAUST Repository

    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.

  19. Activities for gaining insight into IASCC and continuous evaluation of in-service inspection data; Arbeiten zu IASCC und Kontinuierliche Auswertung und Bewertung der Ergebnisse der wiederkehrenden Pruefungen

    Energy Technology Data Exchange (ETDEWEB)

    Huettner, F.; Weber, G.; Wuensch, G.

    1999-06-01

    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) [German] Ziel des Berichts ist es, die aus internationalen Untersuchungen bekannt gewordenen wichtigsten Erkenntnisse zu Umfang, Mechanismen, Charakterisierung und Vermeidung von IASCC in Leichtwasserreaktoren zusammenzufassen. Die Ergebnisse lassen sich wie folgt zusammenfassen: Die Zahl der eindeutig auf IASCC zurueckzufuehrenden Schadensfaelle ist gering im Vergleich zur Anzahl der Schaeden infolge interkristalliner Spannungsrisskorrosion (IGSCC). Insgesamt ist bei der Beurteilung von Risslorrosionsschaeden an RDB-Einbauten in SWR in juengerer Zeit die Tendenz zu verzeichnen, dass bei Rissbildungen, welche zunaechst ursaechlich der IASCC zugeordnet wurden, zunehmend interkristalline Spannungsrisskorrosion (IGSCC) als wahrscheinliche Schadensursache in Betracht gezogen wird. Insgesamt ist der Wissensstand ueber den Einfluss ionisierender Strahlung auf das Korrosionsverhalten von LWR-Werkstoffen noch lueckenhaft. (orig./MM)

  20. Gain control mechanisms in spinal motoneurons

    Directory of Open Access Journals (Sweden)

    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.

  1. Gain Efficient L-band EDFA With Dynamic Gain Equalization

    Institute of Scientific and Technical Information of China (English)

    Xiaoli Hui; Rujian Lin

    2003-01-01

    A gain efficient L-band erbium-doped fiber amplifier with dynamic gain equalization is presented. Using a single fiber Bragg grating and a static equalizer, the gain is clamped at 27dB with less than 0.5dB variations over 35nm.

  2. Low Dark-Current, High Current-Gain of PVK/ZnO Nanoparticles Composite-Based UV Photodetector by PN-Heterojunction Control

    Directory of Open Access Journals (Sweden)

    Sang-Won Lee

    2016-01-01

    Full Text Available We propose a solution-processable ultraviolet (UV photodetector with a pn-heterojunction hybrid photoactive layer (HPL that is composed of poly-n-vinylcarbazole (PVK as a p-type polymer and ZnO nanoparticles (NPs as an n-type metal oxide. To observe the effective photo-inducing ability of the UV photodetector, we analyzed the optical and electrical properties of HPL which is controlled by the doping concentration of n-type ZnO NPs in PVK matrix. Additionally, we confirmed that the optical properties of HPL dominantly depend on the ZnO NPs from the UV-vis absorption and the photoluminescence (PL spectral measurements. This HPL can induce efficient charge transfer in the localized narrow pn-heterojunction domain and increases the photocurrent gain. It is essential that proper doping concentration of n-type ZnO NPs in polymer matrix is obtained to improve the performance of the UV photodetector. When the ZnO NPs are doped with the optimized concentration of 3.4 wt.%, the electrical properties of the photocurrent are significantly increased. The ratio of the photocurrent was approximately 103 higher than that of the dark current.

  3. Low Dark-Current, High Current-Gain of PVK/ZnO Nanoparticles Composite-Based UV Photodetector by PN-Heterojunction Control.

    Science.gov (United States)

    Lee, Sang-Won; Cha, Seung-Hwan; Choi, Kyung-Jae; Kang, Byoung-Ho; Lee, Jae-Sung; Kim, Sae-Wan; Kim, Ju-Seong; Jeong, Hyun-Min; Gopalan, Sai-Anand; Kwon, Dae-Hyuk; Kang, Shin-Won

    2016-01-07

    We propose a solution-processable ultraviolet (UV) photodetector with a pn-heterojunction hybrid photoactive layer (HPL) that is composed of poly-n-vinylcarbazole (PVK) as a p-type polymer and ZnO nanoparticles (NPs) as an n-type metal oxide. To observe the effective photo-inducing ability of the UV photodetector, we analyzed the optical and electrical properties of HPL which is controlled by the doping concentration of n-type ZnO NPs in PVK matrix. Additionally, we confirmed that the optical properties of HPL dominantly depend on the ZnO NPs from the UV-vis absorption and the photoluminescence (PL) spectral measurements. This HPL can induce efficient charge transfer in the localized narrow pn-heterojunction domain and increases the photocurrent gain. It is essential that proper doping concentration of n-type ZnO NPs in polymer matrix is obtained to improve the performance of the UV photodetector. When the ZnO NPs are doped with the optimized concentration of 3.4 wt.%, the electrical properties of the photocurrent are significantly increased. The ratio of the photocurrent was approximately 10³ higher than that of the dark current.

  4. 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

    International Nuclear Information System (INIS)

    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

  5. Cash and in-kind transfers lead to excess weight gain in a population of women with a high prevalence of overweight in rural Mexico.

    Science.gov (United States)

    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

  6. Teacher-and child-managed academic activities in preschool and kindergarten and their influence on children's gains in emergent academic skills

    NARCIS (Netherlands)

    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. Cationic zinc enolates as highly active catalysts for acrylate polymerization.

    Science.gov (United States)

    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

  8. Gain modulation by graphene plasmons in aperiodic lattice lasers

    Science.gov (United States)

    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.

  9. Reducing gain shifts in photomultiplier tubes

    Science.gov (United States)

    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.

  10. Asthma Triggers: Gain Control

    Science.gov (United States)

    ... 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 ...

  11. Gain Flattening Filter Canceling Temperature Dependence of EDFA s gain

    Institute of Scientific and Technical Information of China (English)

    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.

  12. High resolution radar rainfall for urban pluvial flood managementmanagement: Lessons learnt from 10 pilots in North-West Europe within the RainGain project

    NARCIS (Netherlands)

    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

  13. 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

    Science.gov (United States)

    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...

  14. Noise Temperature Characteristics and Gain-control of Avalanche Photodiodes for Laser Radar

    Institute of Scientific and Technical Information of China (English)

    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.

  15. 大功率激光脉冲二极管触发高增益光导开关实验研究%Experimental study of high gain PCSS triggered by high-power pulse laser diode

    Institute of Scientific and Technical Information of China (English)

    王卫; 刘毅; 谌怡; 夏连胜; 杨超; 叶茂

    2016-01-01

    A new kind of high-power pulse laser diode has been researched,and it is mainly used for triggering high-gain gallium arsenide photoconductive semiconductor switch (GaAs PCSS)in experiments.The driver of the laser diode is based on RF MOSFET and it provides an ultra-fast pulse drive current for the laser diode,and the rise-time,FWHM and peak current of the drive current are 4 ns,20 ns and 130 A,respectively.The characteristics of the laser diode have been researched,including laser pulse waveform,energy,power,optical field distribution,and so on.In the Blumlein transmission line structure,the influences of bias voltage,laser spot size,laser energy and laser power on the on-state resistance and jitter of the GaAs PCSS are analyzed. Experiment shows that,lager and more uniform laser spot,higher laser energy and power all help to improve the performance of PCSS.%研究了一种新型大功率激光脉冲二极管的输出特性,该激光二极管主要用于触发工作在高增益模式下的砷化镓光导开关。研制了基于射频金属-氧化物半导体场效应管的激光二极管驱动电路,可以为激光二极管提供上升沿、半高宽和峰值电流分别为4 ns,20 ns 和130 A 的脉冲驱动电流。研究了激光二极管输出的激光脉冲波形、能量、功率、光场分布等特性,并在 Blumlein 传输线结构中,研究了该大功率激光脉冲二极管的输出特性对工作于高增益模式下的光导开关的导通电阻、开关抖动等主要导通性能参数的影响规律。实验结果表明,激光脉冲的能量和功率越大,光斑面积越大、分布越均匀,在相同偏置电压条件下,光导开关的导通性能越好。

  16. Intraperitoneal Injection of Clodronate Liposomes Eliminates Visceral Adipose Macrophages and Blocks High-fat Diet-induced Weight Gain and Development of Insulin Resistance

    OpenAIRE

    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...

  17. Gains in QTL detection using an ultra-high density SNP map based on population sequencing relative to traditional RFLP/SSR markers.

    Directory of Open Access Journals (Sweden)

    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.

  18. 78 FR 70567 - Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology; Final...

    Science.gov (United States)

    2013-11-26

    ... SECURITY Coast Guard Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology...) and Ultra High Frequency (UHF) Sound Navigation and Ranging (SONAR) Technology and Finding of No Significant Impact (FONSI). The USCG is proposing the nationwide use of active SONAR technologies that...

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

    International Nuclear Information System (INIS)

    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)

  20. 高频增益符号未知时的变结构模型参考自适应控制%Variable Structure Model Reference Adaptive Control with Unknown High Frequency Gain Sign

    Institute of Scientific and Technical Information of China (English)

    董文瀚; 孙秀霞; 林岩

    2007-01-01

    A variable structure model reference adaptive control for plants with relative degree greater than one and unknown high frequency gain sign is proposed. A switching scheme is introduced based on a monitoring function designed for the first auxiliary error of the close loop system. It is shown that under the supervision of the monitoring function, the switching stops after at most a finite number of switchings and the tracking error converges to a residual set that can be made arbitrarily small by appropriately choosing some design parameters.

  1. Metallomics for drug development: a further insight into intracellular activation chemistry of a ruthenium(III)-based anticancer drug gained using a multidimensional analytical approach.

    Science.gov (United States)

    Matczuk, Magdalena; Prządka, Monika; Aleksenko, Svetlana S; Czarnocki, Zbigniew; Pawlak, Katarzyna; Timerbaev, Andrei R; Jarosz, Maciej

    2014-01-01

    The mechanism by which the most relevant ruthenium anticancer drugs are activated in tumors to commence their tumor-inhibiting action remains one of the challenging research tasks of present-day metallomics. This contribution aims to capture and identify eventually more reactive species of one of two bis-indazole tetrachloridoruthenate(III) compounds that are progressing in clinical trials. In view of the fact that the transport of ruthenium into cancer cells is governed by transferrin receptors, the susceptibility of the Ru drug adduct with holo-transferrin to exposure by glutathione and ascorbic acid (at their cancer cytosol concentrations) was studied by inductively coupled plasma mass spectrometry (ICP-MS), following isolation of the reaction products by ultrafiltration. Next, capillary electrophoresis coupled to ICP-MS was applied to monitor changes in the Ru speciation both under simulated cancer cytosol conditions and in real cytosol and to assign the charge state of novel metal species. The latter were identified by using tandem electrospray ionization MS in the respective ion mode. The formation of ruthenium(II) species was for the first time revealed, in which the central metal is coordinated by the reduced (GSH) or the oxidized (GSSG) form of glutathione, i.e. [Ru(II)HindCl4(GSH)](2-) and [Ru(II)HindCl4(GSSG)](2-), respectively (Hind = indazole). Ascorbic acid released the ruthenium functionality from the protein-bound form in a different way, the products of adduct cleavage containing aqua ligands. Distribution of low-molecular mass species of Ru in human cytosol was found to have very much in common with the ruthenium speciation assayed under simulated cytosol conditions.

  2. Fetal Programming of Obesity: Maternal Obesity and Excessive Weight Gain

    OpenAIRE

    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. The V1 Population Gains Normalization

    NARCIS (Netherlands)

    Ganmor, Elad; Okun, Michael; Lampl, Ilan

    2009-01-01

    In this issue of Neuron, Busse et al. describe the population response to superimposed visual stimuli while Sit et al. examine the spatiotemporal evolution of cortical activation in response to small visual stimuli. Surprisingly, these two studies of V1 report that a single gain control model accoun

  4. High-Throughput Screening for Streptomyces Antibiotic Biosynthesis Activators

    OpenAIRE

    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.

  5. Murine erythrocytes contain high levels of lysophospholipase activity

    NARCIS (Netherlands)

    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

  6. Evaluation of groundwater residence time in a high mountain aquifer system (Sacramento Mountains, USA): insights gained from use of multiple environmental tracers

    Science.gov (United States)

    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.

  7. Experimental studies of high order soliton compression effect and gain characteristics in femtosecond laser pulses E3+r-doped fiber amplifier

    Institute of Scientific and Technical Information of China (English)

    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.

  8. Plasmonic modulator based on gain-assisted metal-semiconductor-metal waveguide

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia E.; Kulkova, Irina V.; Malureanu, Radu;

    2012-01-01

    We investigate plasmonic modulators with a gain material to be implemented as ultra-compact and ultra-fast active nanodevices in photonic integrated circuits. We analyze metal-semiconductor-metal (MSM) waveguides with InGaAsP-based active material layers as ultra-compact plasmonic modulators....... The modulation is achieved by changing the gain of the core that results in different transmittance through the waveguides. A MSM waveguide enables high field localization and therefore high modulation speed. Bulk semiconductor, quantum wells and quantum dots, arranged in either horizontal or vertical layout......, are considered as the core of the MSM waveguide. Dependences on the waveguide core size and gain values of various active materials are studied. The designs consider also practical aspects like n- and p-doped layers and barriers in order to obtain results as close to reality. The effective propagation constants...

  9. NOX Activity in Brain Aging: Exacerbation by High Fat Diet

    OpenAIRE

    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...

  10. Gain Flattening Filter Canceling Temperature Dependence of EDFA's gain

    Institute of Scientific and Technical Information of China (English)

    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.

  11. High physical activity in young children suggests positive effects by altering autoantigen-induced immune activity.

    Science.gov (United States)

    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

  12. Super-SERS-active and highly effective antimicrobial Ag nanodendrites

    Science.gov (United States)

    Li, H. B.; Liu, P.; Liang, Y.; Xiao, J.; Yang, G. W.

    2012-07-01

    We have developed simple and green electrochemistry to synthesize Ag nanostructures with high purity, good crystallinity and smooth surface for applications as super-SERS (surface-enhanced Raman scattering), SERS-active substrates and with highly effective antimicrobial activities. This synthesis takes place in a clean and slow reaction environment without any chemical additives, which ensures an ultrahigh active surface of the as-synthesized Ag nanostructures owing to their purity, good crystallinity and smooth morphology. Using this method, we synthesized nearly perfect Ag nanodendrites (NDs), which exhibit super-SERS sensitivity when they are used to detect the SERS spectra of rhodamine 6G at concentrations as low as 5 × 10-16 M, and have an ultrahigh electromagnetic (EM) enhancement factor of the order of 1013, breaking through the theoretical limit of EM enhancement. Meanwhile, the as-synthesized Ag NDs possess highly effective antimicrobial activities for Escherichia coli, Candida albicans and Staphylococcus aureus, which are over 10 times that of silver nanoparticles. Additionally, the basic physics and chemistry involved in the fabrication of Ag nanostructures are pursued. These investigations show that silver nanostructures with highly active surfaces can make the most of Ag nanostructures functioning as super-SERS-active substrates and multiple antibiotics.

  13. Speech perception of noise with binary gains

    DEFF Research Database (Denmark)

    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....

  14. Seasonal Variations of Cell Site Diversity Gain

    Directory of Open Access Journals (Sweden)

    Sharmini Enoch

    2016-08-01

    Full Text Available The broadband fixed wireless access (BFWA systems operate in microwave frequencies. In this frequency range, the wave propagation is highly influenced by precipitation caused especially by rain. With the use of cell site diversity (CSD, the rain attenuation effects can be mitigated. When the signal level falls below a certain threshold the subscriber station switches to another base station within the coverage area. This paper aims at demonstrating the performance improvements obtained with the use of cell site diversity during various seasons for measurements carried out from HYREX rain gauge network in UK. The parameters traditionally used to quantify cell site diversity are CSD gain and diversity improvement. This paper analyzes the CSD gain achieved. The gain increases with increasing frequency and distance. The link performance is compared for various seasons and the results show that the maximum attenuation occurs during summer, while the least attenuation occurs during winter. Therefore, maximum gain of up to 22 dB occurs at 54 GHz frequency during winter. The second observation is that when the angular separation between the diversity sites is 180° separation there is maximum gain for all seasons.

  15. A New Organic/Inorganic Hybrid with High Electrorheological Activity

    Science.gov (United States)

    Zhao, X. P.; Duan, X.

    In-situ sol-gel method to prepare colloidal hybrids of surfactant modified polysucchride and titanium oxide has been presented, and experiments indicated these highly ER active particles exhibited a remarkable ER effect. The static shear stress can be up to 37 k Pa (shear rate 5 S-1) under DC field of 4 kV/mm at root temperature, well above that of simple blends of starch and TiO2. In the meanwhile, temperature dependence and sedimentation stability were also greatly improved. Based on recent experimental facts, we find that dielectric properties and surface (interface) activity are two necessary conditions fulfilling the requirement of high ER activity. Adequate grinding of particles with oil can effectively enhance the shear stress, which may be owed to the decline of the activation energy needed for restructuring. It has provided us a new horizon for preparation of excellent ER materials and further studies should be continued to make.

  16. Polyol synthesis of highly active PtRu/C catalyst with high metal loading

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Shiyou; Sun, Gongquan; Tian, Juan; Jiang, Luhua; Qi, Jing; Xin, Qin [Direct Alcohol Fuel Cell Laboratory, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian (China)

    2006-12-01

    Highly loaded PtRu/C catalyst with high activity toward methanol electrooxidation was synthesized via a modified polyol process. XRD patterns indicated that the prepared catalyst was highly alloyed and TEM results showed that the metal nanoparticles were small and uniformly distributed on the carbon support despite the high metal loading. EDX results suggested that the two metals distributed uniformly in the catalyst. Electrochemical characterization and single cell test jointly showed that the prepared 40-20wt.%PtRu/C catalyst possessed high activity toward methanol electrooxidation. (author)

  17. Heritability of gestational weight gain

    DEFF Research Database (Denmark)

    Andersson, Elina Scheers; Silventoinen, Karri; Tynelius, Per;

    2015-01-01

    Gestational weight gain (GWG) is a complex trait involving intrauterine environmental, maternal environmental, and genetic factors. However, the extent to which these factors contribute to the total variation in GWG is unclear. We therefore examined the genetic and environmental influences...

  18. Low-temperature characteristics of the current gain of GaN/InGaN double-heterojunction bipolar transistors

    Science.gov (United States)

    Nishikawa, Atsushi; Kumakura, Kazuhide; Kasu, Makoto; Makimoto, Toshiki

    2009-05-01

    We investigated the temperature dependence of the current gain of npn-type GaN/InGaN double-heterojunction bipolar transistors (DHBTs) in the low-temperature region. The current gain increased with decrease in device temperature due to the reduction of the recombination current in the p-type base layer. The current gain reached as high as 5000 at 40 K, which is the highest among nitride-based HBTs. For conventional HBTs made of InP or GaAs, the current gain decreased with decreasing device temperature. However, no reduction of the current gain was observed in this study, suggesting that the minority carrier mobility in the p-type InGaN base layer has negative temperature dependence, presumably because the ionized impurity scattering is relatively unaffected owing to the carrier freezeout and the high activation energy of Mg in the p-InGaN base layer.

  19. Theaflavin Synthesized in a Selective, Domino-Type, One-Pot Enzymatic Biotransformation Method with Camellia sinensis Cell Culture Inhibits Weight Gain and Fat Accumulation to High-Fat Diet-Induced Obese Mice.

    Science.gov (United States)

    Takemoto, Masumi; Takemoto, Hiroaki; Saijo, Ryoyasu

    2016-08-01

    The polyphenolic compound theaflavin, which is the main red pigment present in black tea, is reported to elicit various physiological effects. Because of the extremely low concentration of theaflavin present in black tea, its extraction from black tea leaves in quantities sufficient for use in medical studies has been difficult. We have developed a simple, inexpensive, selective, domino-type, one-pot enzymatic biotransformation method for the synthesis of theaflavin that is suitable for use in medical studies. Subsequent administration of this synthetic theaflavin to high-fat diet-induced obese mice inhibited both body weight gain and visceral fat accumulation, with no significant difference in the amount of faeces between the experimental and control mice. PMID:27237789

  20. Recommendations of activity restriction in high-risk pregnancy scenarios

    DEFF Research Database (Denmark)

    Bendix, Jane; Hegaard, Hanne Kristine; Bergholt, Thomas;

    2015-01-01

    and the Danish Association of Midwives were asked to complete a tested, structured questionnaire. Results: We sent 1815 invitations; the overall response rate was 54%. A majority of clinicians recommended some form of activity restriction in the nine scenarios. The midwives recommended strict or moderate...... to the obstetricians, the midwives also reported that they expected the recommendation to be more effective. Most midwives and obstetricians reported that they thought strict activity restriction was associated with severe or moderate adverse effect, and recommended antithrombotic prophylaxis. Conclusions: Danish...... obstetricians and midwives prescribe activity restriction in most high-risk pregnancies. The degree of activity restriction and the presumed effect vary between clinicians. This may reflect different attitudes and lack of guidelines based on clinical studies of a possible benefit of activity restriction....

  1. Highly Active Rutile TiO2 for Photocatalysis

    Institute of Scientific and Technical Information of China (English)

    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.

  2. High lightning activity in maritime clouds near Mexico

    Directory of Open Access Journals (Sweden)

    B. Kucienska

    2012-01-01

    Full Text Available Lightning activity detected by the World Wide Lightning Location Network (WWLLN over oceanic regions adjacent to Mexico is often as high as that observed over the continent. In order to explore the possible cause of the observed high flash density over those regions, the relationships between lightning, rainfall, vertical hydrometeor profiles, latent heating, wind variability and aerosol optical thickness are analyzed. The characteristics of lightning and precipitation over four oceanic zones adjacent to Mexican coastlines are contrasted against those over the continent. In addition, we compare two smaller regions over the Tropical Pacific Ocean: one located within the Inter-Tropical Converge Zone and characterized by high rainfall and weak lightning activity and the other influenced by a continental jet and presenting high rainfall and strong lightning activity over the Gulf of Tehuantepec. Maritime precipitating clouds that develop within the region influenced by offshore winds exhibit similar properties to continental clouds: large content of precipitation ice and an increased height range of coexistence of precipitation ice and cloud water. During the rainy season, monthly distribution of lightning within the region influenced by the continental jet is contrary to that of rainfall. Moreover, the monthly variability of lightning is very similar to the variability of the meridional wind component and it is also related to the variability of aerosol optical depth. The analysis strongly suggests that the high lightning activity observed over the Gulf of Tehuantepec is caused by continental cloud condensation nuclei advected over the ocean.

  3. Developmental gains in visuospatial memory predict gains in mathematics achievement.

    Science.gov (United States)

    Li, Yaoran; Geary, David C

    2013-01-01

    Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4) were larger than gains in the capacity of the central executive (d = 1.6) that in turn were larger than gains in phonological memory span (d = 1.1). First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning.

  4. Developmental gains in visuospatial memory predict gains in mathematics achievement.

    Directory of Open Access Journals (Sweden)

    Yaoran Li

    Full Text Available Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4 were larger than gains in the capacity of the central executive (d = 1.6 that in turn were larger than gains in phonological memory span (d = 1.1. First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning.

  5. A high-fat diet impairs cooling-evoked brown adipose tissue activation via a vagal afferent mechanism.

    Science.gov (United States)

    Madden, Christopher J; Morrison, Shaun F

    2016-08-01

    In dramatic contrast to rats on a control diet, rats maintained on a high-fat diet (HFD) failed to activate brown adipose tissue (BAT) during cooling despite robust increases in their BAT activity following direct activation of their BAT sympathetic premotor neurons in the raphe pallidus. Cervical vagotomy or blockade of glutamate receptors in the nucleus of the tractus solitarii (NTS) reversed the HFD-induced inhibition of cold-evoked BAT activity. Thus, a HFD does not prevent rats from mounting a robust, centrally driven BAT thermogenesis; however, a HFD does alter a vagal afferent input to NTS neurons, thereby preventing the normal activation of BAT thermogenesis to cooling. These results, paralleling the absence of cooling-evoked glucose uptake in the BAT of obese humans, reveal a neural mechanism through which consumption of a HFD contributes to reduced energy expenditure and thus to weight gain. PMID:27354235

  6. High hydrostatic pressure treatment of porcine oocytes induces parthenogenetic activation

    DEFF Research Database (Denmark)

    Lin, Lin; Pribenszky, Csaba; Molnár, Miklós;

    2010-01-01

    An innovative technique called high hydrostatic pressure (HHP) treatment has recently been reported to improve the cryosurvival of gametes and embryos in certain mammalian species, including the mouse, pig, and cattle. In the present study the parthenogenetic activation (PA) of pig oocytes caused...

  7. Selection of quiescent Escherichia coli with high metabolic activity.

    Science.gov (United States)

    Sonderegger, Marco; Schümperli, Michael; Sauer, Uwe

    2005-01-01

    Sustained metabolic activity in non-growing, quiescent cells can increase the operational life-span of bio-processes and improve process economics by decoupling production from cell growth. Because of the ill-defined molecular nature of this phenotype, we developed selection protocols for the evolution of quiescent Escherichia coli mutants that exhibit high metabolic activity in ammonium starvation-induced stationary phase. The best enrichment procedures were continuously or discontinuously fed ammonium-limited chemostat cultures with a very low dilution rate of 0.03 h(-1). After 40 generations of selection, improved mutants with up to doubled catabolic rates in stationary phase were isolated. The metabolically most active clones were identified by screening for high specific glucose uptake rates during ammonium starvation-induced stationary phase in deep-well microtiter plates. PMID:15721805

  8. Design of a 16-element Broadband and High Gain Microstrip Array Antenna%一种宽频带高增益16单元微带天线阵设计*

    Institute of Scientific and Technical Information of China (English)

    倪国旗; 梁军; 余白平; 张涛

    2013-01-01

      设计了一个中心频率为6.52 GHz具有宽频带高增益特性的16单元微带天线阵。综合运用H型缝隙耦合馈电技术、插入空气层技术和在贴片天线上切角的方法展宽天线的带宽。该天线阵由两层介质板构成,采用反相馈电可抑制高次模的耦合,交叉极化电平低。使用三维电磁场仿真软件Ansoft HFSS对该天线阵进行仿真优化,并根据仿真结果做成实物加以验证。对实物的测量结果表明:天线阵仿真阻抗带宽(S11≤-10 dB)为21.5%,增益为19.85 dB;实测阻抗带宽(S11≤-10 dB)为22.5%,增益为18.8 dB。天线阵性能良好,能满足工程实际要求。%  A broadband and high gain 16-element microstrip array antenna working at 6.52 GHz is designed in this paper. The H-shaped aperture-coupled feeding,inserting the air layer technology and cutting down squares at the patch antenna are adopted to achieve wider bandwidths. The antenna array is consisted of double-layered substrates. The anti-phase feeding technique that contributes to suppress the higher order modes and decrease cross-polarization is also applied. A 3D electromagnetic software(Ansoft HFSS)is used to simulate and optimize the antenna. According to simulated and optimized results,antenna array is manufactured. The simulation results show that the impedance bandwidth of the microstrip array antenna is as good as 21.5%(S11≤ - 10 dB)and the gain is 19.85 dB. And the measured results is that the impedance bandwidth of the microstrip array antenna is as good as 22.5%(S11≤ - 10 dB)and the gain is 18.8 dB. Therefore,the antenna array with good perfor-mance can meet the practical requirements.

  9. Nitric oxide impacts on angiotensin AT2 receptor modulation of high-pressure baroreflex control of renal sympathetic nerve activity in anaesthetized rats

    OpenAIRE

    Abdulla, M H; Johns, E. J.

    2013-01-01

    Aim Nitric oxide (NO) interacts with the local brain renin-angiotensin system to modulate sympathetic outflow and cardiovascular homoeostasis. This study investigated whether NO influenced the ability of angiotensin AT2 receptor activation to modify the high-pressure baroreceptor regulation of renal sympathetic nerve activity (RSNA) and heart rate (HR). Methods Anaesthetized (chloralose/urethane) rats were prepared to allow generation of baroreflex gain curves for RSNA or HR following intrace...

  10. High efficiency cell-specific targeting of cytokine activity

    Science.gov (United States)

    Garcin, Geneviève; Paul, Franciane; Staufenbiel, Markus; Bordat, Yann; van der Heyden, José; Wilmes, Stephan; Cartron, Guillaume; Apparailly, Florence; de Koker, Stefaan; Piehler, Jacob; Tavernier, Jan; Uzé, Gilles

    2014-01-01

    Systemic toxicity currently prevents exploiting the huge potential of many cytokines for medical applications. Here we present a novel strategy to engineer immunocytokines with very high targeting efficacies. The method lies in the use of mutants of toxic cytokines that markedly reduce their receptor-binding affinities, and that are thus rendered essentially inactive. Upon fusion to nanobodies specifically binding to marker proteins, activity of these cytokines is selectively restored for cell populations expressing this marker. This ‘activity-by-targeting’ concept was validated for type I interferons and leptin. In the case of interferon, activity can be directed to target cells in vitro and to selected cell populations in mice, with up to 1,000-fold increased specific activity. This targeting strategy holds promise to revitalize the clinical potential of many cytokines.

  11. Review of actuators for high speed active flow control

    Institute of Scientific and Technical Information of China (English)

    WANG Lin; LUO ZhenBing; XIA ZhiXun; LIU Bing; DENG Xiong

    2012-01-01

    Actuators are one of the key points for the development of active flow control technology.Efficient methods of high speed flow control can provide enhanced propulsive efficiency and at the same time enable safe and maneuverable high speed flight.The development of high speed flight technology promotes the emergence of novel and robust actuators.This review introduces the state of the art in the development of actuators that can be used in high speed active flow control.The classification and different operation criteria of the actuators are discussed.The specifications,mechanisms and applications of various popular actuator types including fluidic,mechanical,and plasma actuators are described.Based on the realistic need of high speed flow control and the existing results of actuators,a new actuator design method is proposed.At last,the merits and drawbacks of the actuators are summarized and some suggestions on the development of active flow control technology are put forward.

  12. The snooze of lose: Rapid reaching reveals that losses are processed more slowly than gains.

    Science.gov (United States)

    Chapman, Craig S; Gallivan, Jason P; Wong, Jeremy D; Wispinski, Nathan J; Enns, James T

    2015-08-01

    Decision making revolves around weighing potential gains and losses. Research in economic decision making has emphasized that humans exercise disproportionate caution when making explicit choices involving loss. By comparison, research in perceptual decision making has revealed a processing advantage for targets associated with potential gain, though the effects of loss have been explored less systematically. Here, we use a rapid reaching task to measure the relative sensitivity (Experiment 1) and the time course (Experiments 2 and 3) of rapid actions with regard to the reward valence and probability of targets. We show that targets linked to a high probability of gain influence actions about 100 ms earlier than targets associated with equivalent probability and value of loss. These findings are well accounted for by a model of stimulus response in which reward modulates the late, postpeak phase of the activity. We interpret our results within a neural framework of biased competition that is resolved in spatial maps of behavioral relevance. As implied by our model, all visual stimuli initially receive positive activation. Gain stimuli can build off of this initial activation when selected as a target, whereas loss stimuli have to overcome this initial activation in order to be avoided, accounting for the observed delay between valences. Our results bring clarity to the perceptual effects of losses versus gains and highlight the importance of considering the timeline of different biasing factors that influence decisions. PMID:26097977

  13. Stacked Transformer for Driver Gain and Receive Signal Splitting

    Science.gov (United States)

    Driscoll, Kevin R.

    2013-01-01

    In a high-speed signal transmission system that uses transformer coupling, there is a need to provide increased transmitted signal strength without adding active components. This invention uses additional transformers to achieve the needed gain. The prior art uses stronger drivers (which require an IC redesign and a higher power supply voltage), or the addition of another active component (which can decrease reliability, increase power consumption, reduce the beneficial effect of serializer/deserializer preemphasis or deemphasis, and/or interfere with fault containment mechanisms), or uses a different transformer winding ratio (which requires redesign of the transformer and may not be feasible with high-speed signals that require a 1:1 winding ratio). This invention achieves the required gain by connecting the secondaries of multiple transformers in series. The primaries of these transformers are currently either connected in parallel or are connected to multiple drivers. There is also a need to split a receive signal to multiple destinations with minimal signal loss. Additional transformers can achieve the split. The prior art uses impedance-matching series resistors that cause a loss of signal. Instead of causing a loss, most instantiations of this invention would actually provide gain. Multiple transformers are used instead of multiple windings on a single transformer because multiple windings on the same transformer would require a redesign of the transformer, and may not be feasible with high-speed transformers that usually require a bifilar winding with a 1:1 ratio. This invention creates the split by connecting the primaries of multiple transformers in series. The secondary of each transformer is connected to one of the intended destinations without the use of impedance-matching series resistors.

  14. A highly sensitive chemosensor for solution based on organic semiconductor laser gain media%基于有机半导体激光材料的高灵敏度溶液检测传感器件∗

    Institute of Scientific and Technical Information of China (English)

    池浪; 费洪涛; 王腾; 易建鹏; 方月婷; 夏瑞东

    2016-01-01

    Laser has been widely applied in the scientific and engineering areas including communications, medical treatment, industry, and military due to its extremely strict monochromaticity, high coherence and high energy density. Organic laser based on solution processable polymer gain media has attracted considerable attention in various applications due to its easy fabrication, compact system and flexibility. At present, the chemosensors based on organic semiconductor laser have been widely developed. It has been reported to achieve solution monitoring by organic DFB (distributed feedback) laser. Although the method has its own advantages, there are still many operability and craftsmanship problems to be resolved. In this paper we introduce a new type of the real-time monitoring for various solution. The monitor is realized by using amplified spontaneous emission (ASE) from optically pumped organic semiconductor gain media. The gain media comprising blends of poly(9, 9-dioctylfluorene-co-benzothiadiazole) (F8BT) and poly(3-hexylthiophene) (P3HT) at a ratio of (15:85) wt.%is dissolved into toluene (25 mg/mL). Thin films (90 nm thickness) of P3HT/F8BT are obtained by spin coating (2000 r/min) from solution onto pre-cleaned quartz substrates. The P3HT/F8BT film demonstrates the absorption peak at 471 nm, the PL peak at 622 nm, and the ASE peak at 661 nm with FWHM (full-width-at-half-maximum) linewidth of∼10 nm under the stripe laser pumping. The thin films are, then, covered by droplet of solution to form planar waveguide structure with variable effective refractive index. Upon analyte binding, a change in refractive index at the P3HT/F8BT film surface results in a change in the effective refractive index of the planar waveguide and in turn induces shift of the ASE mode wavelength and variation of ASE threshold of the organic gain media. The changes in ASE wavelength and threshold can be monitored for sensing. The red shift of 4.5 nm in the ASE spectrum is from 661 to

  15. Enzyme-polymer composites with high biocatalytic activity and stability

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jungbae; Kosto, Timothy J.; Manimala, Joseph C.; Nauman, E B.; Dordick, Jonathan S.

    2004-08-22

    We have applied vacuum-spraying and electrospinning to incorporate an enzyme into a polymer matrix, creating a novel and highly active biocatalytic composite. As a unique technical approach, enzymes were co-dissolved in toluene with polymers, and the solvent was then rapidly removed by injecting the mixture into a vacuum chamber or by electrospinning. Subsequent crosslinking of the enzyme with glutaraldehyde resulted in stable entrapped enzyme within the polymeric matrices. For example, an amorphous composite of alpha-chymotrypsin and polyethylene showed no significant loss of enzymatic activity in aqueous buffer for one month. Nanofibers of alpha-chymotrypsin and polystyrene also showed no decrease in activity for more than two weeks. The normalized activity of amorphous composite in organic solvents was 3-13 times higher than that of native alpha-chymotrypsin. The activity of nanofibers was 5-7 times higher than that of amorphous composite in aqueous buffer solution. The composites of alpha-chymotrypsin and polymers demonstrate the feasibility of obtaining a wide variety of active and stable biocatalytic materials with many combinations of enzymes and polymers.

  16. Adsorption of naphthenic acids on high surface area activated carbons.

    Science.gov (United States)

    Iranmanesh, Sobhan; Harding, Thomas; Abedi, Jalal; Seyedeyn-Azad, Fakhry; Layzell, David B

    2014-01-01

    In oil sands mining extraction, water is an essential component; however, the processed water becomes contaminated through contact with the bitumen at high temperature, and a portion of it cannot be recycled and ends up in tailing ponds. The removal of naphthenic acids (NAs) from tailing pond water is crucial, as they are corrosive and toxic and provide a substrate for microbial activity that can give rise to methane, which is a potent greenhouse gas. In this study, the conversion of sawdust into an activated carbon (AC) that could be used to remove NAs from tailings water was studied. After producing biochar from sawdust by a slow-pyrolysis process, the biochar was physically activated using carbon dioxide (CO2) over a range of temperatures or prior to producing biochar, and the sawdust was chemically activated using phosphoric acid (H3PO4). The physically activated carbon had a lower surface area per gram than the chemically activated carbon. The physically produced ACs had a lower surface area per gram than chemically produced AC. In the adsorption tests with NAs, up to 35 mg of NAs was removed from the water per gram of AC. The chemically treated ACs showed better uptake, which can be attributed to its higher surface area and increased mesopore size when compared with the physically treated AC. Both the chemically produced and physically produced AC provided better uptake than the commercially AC. PMID:24766592

  17. A simple and highly effective process for the preparation of activated carbons with high surface area

    Energy Technology Data Exchange (ETDEWEB)

    Li Ying, E-mail: liyingjlu@163.com [College of Chemistry, Jilin University, Changchun 130012 (China); Ding Xuefeng; Guo Yupeng; Wang Lili; Rong Chunguang; Qu Yuning; Ma Xiaoyu [College of Chemistry, Jilin University, Changchun 130012 (China); Wang Zichen, E-mail: wangzc@jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130012 (China)

    2011-06-15

    Highlights: {yields} High surface area activated carbon can be prepared by rice husk H{sub 3}PO{sub 4} without pretreatment. {yields} The characteristics of the activated carbon were greatly influenced by post-processing method. {yields} The lower SiO{sub 2} content of the activated carbons, the higher pore volume the carbons had. {yields} Some silica in rice husk reacted with H{sub 3}PO{sub 4} to form SiP{sub 2}O{sub 7} which could be removed by post-process. - Abstract: Activated carbons with high surface area were prepared by phosphoric acid as activation agent and rice husks as precursors. It was found that the characteristics of the activated carbons were influenced not only by the preparation but also by the post-processing method. The high surface area of the activated carbons was prepared under the optimum condition (50% H{sub 3}PO{sub 4} with impregnation ratio of 5:1, activation temperature of 500 deg. C, activation time of 0.5 h, wash water temperature of 100 deg. C). SiO{sub 2} content could affect the surface area of activated carbons, either. The lower SiO{sub 2} content of the activated carbons, the higher pore volume the carbons had. The SiO{sub 2} content was 11.2% when used the optimum condition. The explanation was that silicon element in rice husks reacted with H{sub 3}PO{sub 4} to form silicon phosphate (SiP{sub 2}O{sub 7}), and it could be proved further by X-ray diffraction analysis, SiP{sub 2}O{sub 7} could be removed by post-process.

  18. Broadband circularly p olarized high-gain antenna design based on single-layer reflecting metasurface%基于单层反射超表面的宽带圆极化高增益天线设计∗

    Institute of Scientific and Technical Information of China (English)

    李唐景; 梁建刚; 李海鹏

    2016-01-01

    According to the Pancharatnam-Berry phase principle, a single-layer reflecting element is proposed for steering the phase of the electromagnetic wave. The structure of the element is composed of metabolic cross wire and copper ground sheet, which are separated by an FR4 dielectric substrate with a thickness of 3 mm. When the incident wave is circularly polarized, different rotary angles of the element are used to achieve the co-polarization reflection with high effciency in a broadband of 11–16 GHz. In the design of the focusing metasurface, the phase compensation for forming a constant aperture phase is provided by the individual reflected element with a different rotated angle. Remarkably, the size of the element is only 5 mm (0.23λ0), and then it can be more accurate to control the phase of the array. The focusing metasurface is composed of 15 × 15 elements with a focal length of 30 mm at 13.5 GHz. The designed sample is simulated in CST Microwave Studio. The results show that the incident circularly polarized plane wave is well transformed into a spherical wave in the band from 11 to 16 GHz, and the focal length is around 30 mm. For further application, a unidirectional Archimedean spiral antenna is located at the focal point of the metasurface. According to the reversibility principle of electromagnetic wave propagation, the spherical wave radiated by the feed antenna is converted into a plane wave by the reflecting metasurface, so that the antenna gain is remarkably enhanced. Through adjusting the distance between the feed antenna and the focusing metasurface, we find that 28 mm is the best distance. Finally, the feed antenna and the metasurface are fabricated, assembled and measured. Numerical and experimental results are in good agreement with each other, showing that the −1 dB gain bandwidth of the high-gain antenna is 12.5–16 GHz, and in this band the peak gains are all over 19 dBc and the axial ratio is better than 3 dB. In addition, the aperture

  19. Stress effects on framed decisions: there are differences for gains and losses

    Directory of Open Access Journals (Sweden)

    Stephan ePabst

    2013-10-01

    Full Text Available Recent studies have shown that acute stress can lead to riskier decision making. Yet, the underlying mechanisms of the stress effects on decisions under risk remain poorly understood. To gain a better understanding of decision-making processes and potential strategy application under stress, we investigated decision making in pure gain and loss domains with unequal expected values across alternatives. We conducted an experimental study with a 2 × 2 design (stress vs. no stress and gain domain vs. loss domain. The Trier Social Stress Test (TSST was utilized to induce acute stress. Controls performed the placebo-TSST. To validate the stress response we measured salivary cortisol and alpha amylase concentrations. We used a modified version of the Game of Dice Task (GDT to assess decision-making performance in a gain and a loss domain. Results showed that non-stressed participants of the gain domain decided less risky compared to those of the loss domain. This behavior is in accordance with previous studies and indicates the stability of the framing effect in even more complex tasks with changing expected values across alternatives. Stress did not alter risk taking behavior in the gain domain. Yet, in the loss domain stressed participants decided less risky compared to controls. Additionally, the data support earlier findings of longer reaction times in loss compared to gain domains due to higher cognitive effort for loss-framed decisions. It is discussed that stress may lead to reduced amygdala activation, which has been found to reduce riskier decisions in a loss domain. With respect to earlier results of riskier decisions in tasks that unite both gain and loss domains, it is discussed whether stress leads to a stronger evaluation of high gains and a neglect of losses.

  20. Heritability of gestational weight gain

    DEFF Research Database (Denmark)

    Andersson, Elina Scheers; Silventoinen, Karri; Tynelius, Per;

    2015-01-01

    Gestational weight gain (GWG) is a complex trait involving intrauterine environmental, maternal environmental, and genetic factors. However, the extent to which these factors contribute to the total variation in GWG is unclear. We therefore examined the genetic and environmental influences on the...