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Sample records for fast decomposed ga

  1. Dynamic strategy based fast decomposed GA coordinated with FACTS devices to enhance the optimal power flow

    Energy Technology Data Exchange (ETDEWEB)

    Mahdad, Belkacem, E-mail: bemahdad@yahoo.f [University of Biskra, Department of Electrical Engineering, Biskra 07000 (Algeria); Bouktir, T. [Oum El Bouaghi, Department of Electrical Engineering, Oum El Bouaghi 04000 (Algeria); Srairi, K. [University of Biskra, Department of Electrical Engineering, Biskra 07000 (Algeria); EL Benbouzid, M. [Laboratoire Brestois de Mecanique et des Systemes, University of Brest (France)

    2010-07-15

    Under critical situation the main preoccupation of expert engineers is to assure power system security and to deliver power to the consumer within the desired index power quality. The total generation cost taken as a secondary strategy. This paper presents an efficient decomposed GA to enhance the solution of the optimal power flow (OPF) with non-smooth cost function and under severe loading conditions. At the decomposed stage the length of the original chromosome is reduced successively and adapted to the topology of the new partition. Two sub problems are proposed to coordinate the OPF problem under different loading conditions: the first sub problem related to the active power planning under different loading factor to minimize the total fuel cost, and the second sub problem is a reactive power planning designed based in practical rules to make fine corrections to the voltage deviation and reactive power violation using a specified number of shunt dynamic compensators named Static Var Compensators (SVC). To validate the robustness of the proposed approach, the proposed algorithm tested on IEEE 30-Bus, 26-Bus and IEEE 118-Bus under different loading conditions and compared with global optimization methods (GA, EGA, FGA, PSO, MTS, MDE and ACO) and with two robust simulation packages: PSAT and MATPOWER. The results show that the proposed approach can converge to the near solution and obtain a competitive solution at critical situation and with a reasonable time.

  2. Self-assembly of Silver Nanoparticles and Multiwall Carbon Nanotubes on Decomposed GaAs Surfaces

    Directory of Open Access Journals (Sweden)

    Unnikrishnan NV

    2010-01-01

    Full Text Available Abstract Atomic Force Microscopy complemented by Photoluminescence and Reflection High Energy Electron Diffraction has been used to study self-assembly of silver nanoparticles and multiwall carbon nanotubes on thermally decomposed GaAs (100 surfaces. It has been shown that the decomposition leads to the formation of arsenic plate-like structures. Multiwall carbon nanotubes spin coated on the decomposed surfaces were mostly found to occupy the depressions between the plates and formed boundaries. While direct casting of silver nanoparticles is found to induce microdroplets. Annealing at 300°C was observed to contract the microdroplets into combined structures consisting of silver spots surrounded by silver rings. Moreover, casting of colloidal suspension consists of multiwall carbon nanotubes and silver nanoparticles is observed to cause the formation of 2D compact islands. Depending on the multiwall carbon nanotubes diameter, GaAs/multiwall carbon nanotubes/silver system exhibited photoluminescence with varying strength. Such assembly provides a possible bottom up facile way of roughness controlled fabrication of plasmonic systems on GaAs surfaces.

  3. Fast and ultrafast processes in AlGaN/GaN channels

    Energy Technology Data Exchange (ETDEWEB)

    Matulionis, A.; Liberis, J.; Ardaravicius, L.; Ramonas, M.; Zubkute, T.; Matulioniene, I. [Semiconductor Physics Institute, A. Goitauto 11, Vilnius 2600 (Lithuania); Eastman, L.F.; Shealy, J.R. [Cornell University, 425 Phillips Hall, Ithaca, NY 14853 (United States); Smart, J. [RF Micro Devices, 10420 Harris Oaks Blvd., Charlotte, NC 28269 (United States); Pavlidis, D.; Hubbard, S. [University of Michigan, 1301 Beal Avenue, Ann Arbor, MI 48109-2122 (United States)

    2002-12-01

    Extrapolated experimental dependence of electron energy relaxation time is used to treat hot-electron sharing by the adjacent Al{sub 0.15}Ga{sub 0.85}N and GaN layers in Al{sub 0.15}Ga{sub 0.85}N/GaN. The results fit the available experimental data on microwave noise when hot-phonon effect on the energy relaxation time is taken into account. The relaxation time of the occupancy fluctuations of the shared states is estimated to be 6 ps at 80 K lattice temperature. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  4. Reduction of fast surface states on p-type GaAs

    Science.gov (United States)

    Ahrenkiel, R. K.; Wagner, R. S.; Pattillo, S.; Dunlavy, D.; Jervis, T.; Kazmerski, L. L.; Ireland, P. J.

    1982-04-01

    Native oxides and oxyfluorides were grown on GaAs by a glow discharge plasma process. Analysis of metal-insulator-semiconductor structures based on oxyfluoride dielectrics indicated vastly different interface properties compared to pure oxide dielectrics. Whereas oxide structures showed high densities of fast surface states, oxyfluorides showed no evidence of such effects.

  5. Time-resolved photo and radio-luminescence studies demonstrate the possibility of using InGaN/GaN quantum wells as fast scintillators.

    Science.gov (United States)

    Balakrishnan, G

    2015-03-06

    In the recent publication by Hospodková et al, the authors investigate III-N quantum well structures as potential fast scintillators (Hospodková et al 2014 Nanotechnology 25 455501). The InGaN/GaN quantum well structures are grown using metal organic vapour phase epitaxy on a sapphire substrate and the fast carrier decay times are characterized by time resolved photo and radioluminescence.

  6. Fast and simple preparation of 68Ga-citrate for routine clinical PET

    DEFF Research Database (Denmark)

    Nielsen, Karin M; Kaufmann, Jens; Mewis, Dennis;

    2013-01-01

    , and the results are presented herein. By eliminating the use of organic solvents, the previously required quality control testing of the final product by gas chromatography can be abandoned. This novel, high-yielding method allows for a more efficient synthesis of ⁶⁸Ga citrate with both shorter production time......, it also provides better quality images whose high resolution permits quantitative analyses, thus improving the management of patients suffering from infections or inflammation. The purpose of our study was to develop a fast and reliable synthesis protocol for the preparation of ⁶⁸Ga citrate under good...

  7. Fast and simple preparation of 68Ga-citrate for routine clinical PET

    DEFF Research Database (Denmark)

    Nielsen, Karin M; Kaufmann, Jens; Mewis, Dennis;

    , and the results are presented herein. By eliminating the use of organic solvents, the previously required quality control testing of the final product by gas chromatography can be abandoned. This novel, high-yielding method allows for a more efficient synthesis of ⁶⁸Ga citrate with both shorter production time......, it also provides better quality images whose high resolution permits quantitative analyses, thus improving the management of patients suffering from infections or inflammation. The purpose of our study was to develop a fast and reliable synthesis protocol for the preparation of ⁶⁸Ga citrate under good...

  8. InGaN/GaN multiple quantum well for fast scintillation application: radioluminescence and photoluminescence study

    Science.gov (United States)

    Hospodková, Alice; Nikl, Martin; Pacherová, Oliva; Oswald, Jiří; Brůža, Petr; Pánek, Dalibor; Foltynski, Bartosz; Hulicius, Eduard; Beitlerová, Alena; Heuken, Michael

    2014-11-01

    We prepare InGaN/GaN multiple quantum well (MQW) structure by metal-organic vapour phase epitaxy and characterize it by fine XRD measurements. We demonstrate its suitability for scintillator application including a unique measurement of wavelength-resolved scintillation response under nanosecond pulse soft x-ray source in extended dynamical and time scales. The photoluminescence and radioluminescence were measured: we have shown that the ratio of the intensity of quantum well (QW) exciton luminescence to the intensity of the yellow luminescence (YL) band IQW/IYL depends strongly on the type and intensity of excitation. Slower scintillation decay measured at YL band maximum confirmed the presence of several radiative recombination centres responsible for wide YL band, which also partially overlap with the QW peak. Further improvements of the structure are suggested, but even the presently reported decay characteristics of the excitonic emission in MQW are better compared to the currently widely used single crystal YAP:Ce or YAG:Ce scintillators. Thus, such a type of a semiconductor scintillator is highly promising for fast detection of soft x-ray and related beam diagnostics.

  9. InGaN/GaN multiple quantum well for fast scintillation application: radioluminescence and photoluminescence study.

    Science.gov (United States)

    Hospodková, Alice; Nikl, Martin; Pacherová, Oliva; Oswald, Jiří; Brůža, Petr; Pánek, Dalibor; Foltynski, Bartosz; Hulicius, Eduard; Beitlerová, Alena; Heuken, Michael

    2014-11-14

    We prepare InGaN/GaN multiple quantum well (MQW) structure by metal-organic vapour phase epitaxy and characterize it by fine XRD measurements. We demonstrate its suitability for scintillator application including a unique measurement of wavelength-resolved scintillation response under nanosecond pulse soft x-ray source in extended dynamical and time scales. The photoluminescence and radioluminescence were measured: we have shown that the ratio of the intensity of quantum well (QW) exciton luminescence to the intensity of the yellow luminescence (YL) band IQW/IYL depends strongly on the type and intensity of excitation. Slower scintillation decay measured at YL band maximum confirmed the presence of several radiative recombination centres responsible for wide YL band, which also partially overlap with the QW peak. Further improvements of the structure are suggested, but even the presently reported decay characteristics of the excitonic emission in MQW are better compared to the currently widely used single crystal YAP:Ce or YAG:Ce scintillators. Thus, such a type of a semiconductor scintillator is highly promising for fast detection of soft x-ray and related beam diagnostics.

  10. Decomposable Effectivity Functions

    NARCIS (Netherlands)

    Otten, G.J.M.

    1995-01-01

    Decomposable effectivity functions are introduced as an extension of additive effectivity functions. Whereas additive effectivity functions are determined by pairs of additive TU-games, decomposable effectivity functions are generated by pairs of TU-games that need not be additive. It turns out that

  11. Fast and high light yield scintillation in the Ga2O3 semiconductor material

    Science.gov (United States)

    Yanagida, Takayuki; Okada, Go; Kato, Takumi; Nakauchi, Daisuke; Yanagida, Satoko

    2016-04-01

    We report the distinct scintillation properties of the well-known Ga2O3 semiconductor material. Under UV excitation, the photoluminescence (PL) emission peak appeared near a wavelength of 380 nm with a quantum yield of 6%, and fast decays of 8 and 793 ns were observed. In contrast, the X-ray-induced scintillation spectrum showed an intense emission band near a wavelength of 380 nm, whose decay curve was reproduced using two exponential decay components with time constants of 8 and 977 ns. The pulse height spectrum of 137Cs γ-rays measured using Ga2O3 showed a clear photoabsorption peak with a light yield of 15000 ± 1500 photons/MeV.

  12. GA-Based Autonomous Design of Robust Fast and Precise Positioning Considering Machine Stand Vibration Suppression

    Science.gov (United States)

    Ito, Kazuaki; Nagata, Ryo; Iwasaki, Makoto; Matsui, Nobuyuki

    This paper presents a novel Genetic Algorithm (GA)-based autonomous compensator design and position command shaping considering the stand vibration suppression for the fast-response and high-precision positioning of mechatronic systems. The positioning system is mainly composed of a robust 2-degrees-of-freedom (2DOF) controller based on the coprime factorization description. The feedback compensator based on H∞ design framework in the 2DOF controller ensures the robustness against the variations of resonant vibration mode. The feedforward compensator and position command, on the other hand, can be autonomously designed by the optimization capability of GA, in order to achieve the desired positioning performance and to suppress the machine stand vibration. The effectiveness of the proposed optimal design has been verified by experiments using a table drive system with ball screw.

  13. Radiation damage in InGaAs photodiodes by 1 MeV fast neutrons

    CERN Document Server

    Ohyama, H; Vanhellemont, J; Takami, Y; Sunaga, H

    1998-01-01

    Irradiation damage in In sub 0 sub . sub 5 sub 3 Ga sub 0 sub . sub 4 sub 7 As p-i-n photodiodes by 1 MeV fast neutrons has been studied as a function of fluence for the first time, and the results are discussed in this paper. The degradation of the electrical and optical performance of diodes increases with increasing fluence. The induced lattice defects in the In sub 0 sub . sub 5 sub 3 Ga sub 0 sub . sub 4 sub 7 As epitaxial layers and the InP substrate are studied by Deep Level Transient Spectroscopy (DLTS) methods. In the In sub 0 sub . sub 5 sub 3 Ga sub 0 sub . sub 4 sub 7 As epitaxial layers, hole and electron capture levels are induced by irradiation. The influence of the type of radiation source on the device degradation is then discussed by comparison to 1 MeV electrons with respect to the numbers of knock-on atoms and the nonionizing energy loss (NIEL). The radiation source dependence of performance degradation is attributed to the difference of mass between the two irradiating particles and the p...

  14. Decomposing the Current

    DEFF Research Database (Denmark)

    Hansen, Tim

    The field of molecular electronics have been shown to span a huge range of properties. In an effort to extract the parameters of the system that governs these properties, a number of methods that decomposes the current have been developed. These methods function not just as tools for data...... extraction, but also serves as the foundation upon which to gain insights into the physics that governs the molecular properties. As such, the understanding of the applicability and the development of new methods to decompose the current may be a goal in it self. In this thesis we will explore some...... of these methods, and use the insights from this study to develop new methods. First, we will compare two methods that decompose the current into the transmission from a single conducting level of the molecular device, by extracting level position and broadening. In general we see that the method that relies on I...

  15. Decomposing the Current

    DEFF Research Database (Denmark)

    Hansen, Tim

    The field of molecular electronics have been shown to span a huge range of properties. In an effort to extract the parameters of the system that governs these properties, a number of methods that decomposes the current have been developed. These methods function not just as tools for data...... extraction, but also serves as the foundation upon which to gain insights into the physics that governs the molecular properties. As such, the understanding of the applicability and the development of new methods to decompose the current may be a goal in it self. In this thesis we will explore some...... of these methods, and use the insights from this study to develop new methods. First, we will compare two methods that decompose the current into the transmission from a single conducting level of the molecular device, by extracting level position and broadening. In general we see that the method that relies on I...

  16. Decomposing generalized quantifiers

    NARCIS (Netherlands)

    Westerståhl, D.

    2008-01-01

    This note explains the circumstances under which a type <1> quantifier can be decomposed into a type <1, 1> quantifier and a set, by fixing the first argument of the former to the latter. The motivation comes from the semantics of Noun Phrases (also called Determiner Phrases) in natural languages, b

  17. Decomposing generalized quantifiers

    NARCIS (Netherlands)

    Westerståhl, D.

    2008-01-01

    This note explains the circumstances under which a type <1> quantifier can be decomposed into a type <1, 1> quantifier and a set, by fixing the first argument of the former to the latter. The motivation comes from the semantics of Noun Phrases (also called Determiner Phrases) in natural languages,

  18. Ozone decomposing filter

    Science.gov (United States)

    Simandl, Ronald F.; Brown, John D.; Whinnery, Jr., LeRoy L.

    1999-01-01

    In an improved ozone decomposing air filter carbon fibers are held together with a carbonized binder in a perforated structure. The structure is made by combining rayon fibers with gelatin, forming the mixture in a mold, freeze-drying, and vacuum baking.

  19. Improvement of luminescence properties of GaN buffer layer for fast nitride scintillator structures

    Science.gov (United States)

    Hubáček, T.; Hospodková, A.; Oswald, J.; Kuldová, K.; Pangrác, J.

    2017-04-01

    We have optimized technology of GaN buffer layer growth with respect to the application in fast scintillation structures. The deep defect luminescence so called yellow band (YB) with decay time up to tens of microseconds is undesired for these applications and should be suppressed or at least the ratio of intensities of excitonic to YB maximum has to be considerably increased. The required photoluminescence properties were achieved by optimization of growth parameters of nucleation and coalescence layer on sapphire substrate. We have shown that decrease of NH3 flow, decrease of coalescence temperature, increase of nucleation time and nucleation pressure lead to improvement of the structure and luminescence properties of the buffer layer. Results indicate a significant increased ratio of excitonic/YB luminescence intensity.

  20. Efficient carrier relaxation and fast carrier recombination of N-polar InGaN/GaN light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Shih-Wei, E-mail: swfeng@nuk.edu.tw; Liao, Po-Hsun [Department of Applied Physics, National University of Kaohsiung, No. 700, Kaohsiung University Rd., Nan Tzu Dist., 811 Kaohsiung, Taiwan (China); Leung, Benjamin; Han, Jung [Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520 (United States); Yang, Fann-Wei [Department of Electronic Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan (China); Wang, Hsiang-Chen [Graduate Institute of Opto-Mechatronics and Advanced Institute of Manufacturing with High-Tech Innovations (AIM-HI), National Chung Cheng University, Chia-Yi, Taiwan (China)

    2015-07-28

    Based on quantum efficiency and time-resolved electroluminescence measurements, the effects of carrier localization and quantum-confined Stark effect (QCSE) on carrier transport and recombination dynamics of Ga- and N-polar InGaN/GaN light-emitting diodes (LEDs) are reported. The N-polar LED exhibits shorter ns-scale response, rising, delay, and recombination times than the Ga-polar one does. Stronger carrier localization and the combined effects of suppressed QCSE and electric field and lower potential barrier acting upon the forward bias in an N-polar LED provide the advantages of more efficient carrier relaxation and faster carrier recombination. By optimizing growth conditions to enhance the radiative recombination, the advantages of more efficient carrier relaxation and faster carrier recombination in a competitive performance N-polar LED can be realized for applications of high-speed flash LEDs. The research results provide important information for carrier transport and recombination dynamics of an N-polar InGaN/GaN LED.

  1. Fast response of the optical nonlinearity in a GaAs/AlGaAs asymmetric triple quantum well structure

    CERN Document Server

    Ahn, S H; Sawaki, N

    1999-01-01

    The time response of the optical nonlinear behavior in a GaAs/AlGaAs asymmetric triple quantum well structure is estimated by using a picosecond pump-probe method at 77 K. From the results of the transmission of the probe pulse as a function of the delay time at the excitation wavelengths, a rise time of 5 approx 10 ps and a fall time of 8 approx 16 ps are obtained. The nonlinear behavior is attributed to the triple resonance of the electronic states due to the build-up of the internal field induced by the separation of photo-excited electrons and holes. It is found that the rise time is determined by the tunneling transfer time of the electrons in the narrowest well to an adjacent well separated by a thin potential barrier.

  2. Fast synthesis and bioconjugation of (68) Ga core-doped extremely small iron oxide nanoparticles for PET/MR imaging.

    Science.gov (United States)

    Pellico, Juan; Ruiz-Cabello, Jesús; Saiz-Alía, Marina; Del Rosario, Gilberto; Caja, Sergio; Montoya, María; Fernández de Manuel, Laura; Morales, M Puerto; Gutiérrez, Lucia; Galiana, Beatriz; Enríquez, Jose A; Herranz, Fernando

    2016-05-01

    Combination of complementary imaging techniques, like hybrid PET/MRI, allows protocols to be developed that exploit the best features of both. In order to get the best of these combinations the use of dual probes is highly desirable. On this sense the combination of biocompatible iron oxide nanoparticles and 68Ga isotope is a powerful development for the new generation of hybrid systems and multimodality approaches. Our objective was the synthesis and application of a chelator-free 68Ga-iron oxide nanotracer with improved stability, radiolabeling yield and in vivo performance in dual PET/MRI. We carried out the core doping of iron oxide nanoparticles, without the use of any chelator, by a microwave-driven protocol. The synthesis allowed the production of extremely small (2.5 nm) 68Ga core-doped iron oxide nanoparticles. The microwave approach allowed an extremely fast synthesis with a 90% radiolabeling yield and T1 contrast in MRI. With the same microwave approach the nano-radiotracer was functionalized in a fast and efficient way. We finally evaluated these dual targeting nanoparticles in an angiogenesis murine model by PET/MR imaging. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Decomposing Multifractal Crossovers

    Science.gov (United States)

    Nagy, Zoltan; Mukli, Peter; Herman, Peter; Eke, Andras

    2017-01-01

    Physiological processes—such as, the brain's resting-state electrical activity or hemodynamic fluctuations—exhibit scale-free temporal structuring. However, impacts common in biological systems such as, noise, multiple signal generators, or filtering by transport function, result in multimodal scaling that cannot be reliably assessed by standard analytical tools that assume unimodal scaling. Here, we present two methods to identify breakpoints or crossovers in multimodal multifractal scaling functions. These methods incorporate the robust iterative fitting approach of the focus-based multifractal formalism (FMF). The first approach (moment-wise scaling range adaptivity) allows for a breakpoint-based adaptive treatment that analyzes segregated scale-invariant ranges. The second method (scaling function decomposition method, SFD) is a crossover-based design aimed at decomposing signal constituents from multimodal scaling functions resulting from signal addition or co-sampling, such as, contamination by uncorrelated fractals. We demonstrated that these methods could handle multimodal, mono- or multifractal, and exact or empirical signals alike. Their precision was numerically characterized on ideal signals, and a robust performance was demonstrated on exemplary empirical signals capturing resting-state brain dynamics by near infrared spectroscopy (NIRS), electroencephalography (EEG), and blood oxygen level-dependent functional magnetic resonance imaging (fMRI-BOLD). The NIRS and fMRI-BOLD low-frequency fluctuations were dominated by a multifractal component over an underlying biologically relevant random noise, thus forming a bimodal signal. The crossover between the EEG signal components was found at the boundary between the δ and θ bands, suggesting an independent generator for the multifractal δ rhythm. The robust implementation of the SFD method should be regarded as essential in the seamless processing of large volumes of bimodal fMRI-BOLD imaging data for

  4. Decomposing Multifractal Crossovers

    Directory of Open Access Journals (Sweden)

    Zoltan Nagy

    2017-07-01

    Full Text Available Physiological processes—such as, the brain's resting-state electrical activity or hemodynamic fluctuations—exhibit scale-free temporal structuring. However, impacts common in biological systems such as, noise, multiple signal generators, or filtering by transport function, result in multimodal scaling that cannot be reliably assessed by standard analytical tools that assume unimodal scaling. Here, we present two methods to identify breakpoints or crossovers in multimodal multifractal scaling functions. These methods incorporate the robust iterative fitting approach of the focus-based multifractal formalism (FMF. The first approach (moment-wise scaling range adaptivity allows for a breakpoint-based adaptive treatment that analyzes segregated scale-invariant ranges. The second method (scaling function decomposition method, SFD is a crossover-based design aimed at decomposing signal constituents from multimodal scaling functions resulting from signal addition or co-sampling, such as, contamination by uncorrelated fractals. We demonstrated that these methods could handle multimodal, mono- or multifractal, and exact or empirical signals alike. Their precision was numerically characterized on ideal signals, and a robust performance was demonstrated on exemplary empirical signals capturing resting-state brain dynamics by near infrared spectroscopy (NIRS, electroencephalography (EEG, and blood oxygen level-dependent functional magnetic resonance imaging (fMRI-BOLD. The NIRS and fMRI-BOLD low-frequency fluctuations were dominated by a multifractal component over an underlying biologically relevant random noise, thus forming a bimodal signal. The crossover between the EEG signal components was found at the boundary between the δ and θ bands, suggesting an independent generator for the multifractal δ rhythm. The robust implementation of the SFD method should be regarded as essential in the seamless processing of large volumes of bimodal f

  5. Decomposable log-linear models

    DEFF Research Database (Denmark)

    Eriksen, Poul Svante

    can be characterized by a structured set of conditional independencies between some variables given some other variables. We term the new model class decomposable log-linear models, which is illustrated to be a much richer class than decomposable graphical models.It covers a wide range of non...

  6. Fast Tuneable InGaAsP DBR Laser Using Quantum-Confined Stark-Effect-Induced Refractive Index Change

    OpenAIRE

    Pantouvaki, M.; Renaud, C. C.; Cannard, P; Robertson, M. J.; Gwilliam, R; Seeds, A. J.

    2007-01-01

    We report a monolithically integrated InGaAsP DBR ridge waveguide laser that uses the quantum-confined Stark effect (QCSE) to achieve fast tuning response. The laser incorporates three sections: a forward-biased gain section, a reverse-biased phase section, and a reverse-biased DBR tuning section. The laser behavior is modeled using transmission matrix equations and tuning over similar to 8 nm is predicted. Devices were fabricated using post-growth shallow ion implantation to reduce the loss ...

  7. Forensic entomology of decomposing humans and their decomposing pets.

    Science.gov (United States)

    Sanford, Michelle R

    2015-02-01

    Domestic pets are commonly found in the homes of decedents whose deaths are investigated by a medical examiner or coroner. When these pets become trapped with a decomposing decedent they may resort to feeding on the body or succumb to starvation and/or dehydration and begin to decompose as well. In this case report photographic documentation of cases involving pets and decedents were examined from 2009 through the beginning of 2014. This photo review indicated that in many cases the pets were cats and dogs that were trapped with the decedent, died and were discovered in a moderate (bloat to active decay) state of decomposition. In addition three cases involving decomposing humans and their decomposing pets are described as they were processed for time of insect colonization by forensic entomological approach. Differences in timing and species colonizing the human and animal bodies were noted as was the potential for the human or animal derived specimens to contaminate one another at the scene.

  8. Fast atom diffraction from a β-Ga{sub 2}O{sub 3}(100) surface

    Energy Technology Data Exchange (ETDEWEB)

    Busch, M.; Meyer, E.; Winter, H. [Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, D-12489 Berlin (Germany); Irmscher, K.; Galazka, Z. [Leibniz-Institut für Kristallzüchtung, Max-Born-Straße 2, D-12489 Berlin (Germany); Gärtner, K. [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, D-07743 Jena (Germany)

    2014-08-04

    Fast H, He atoms, and H{sub 2} molecules with projectile energies ranging from 200 eV up to 3 keV were scattered under a grazing angle of incidence from a clean and flat β-Ga{sub 2}O{sub 3}(100) surface. The bulk single crystal was grown by the Czochralski method and prepared via annealing under ultra-high vacuum conditions. For scattering along low-index directions, we observed defined diffraction patterns in the angular distributions for scattered projectiles. From the analysis of diffraction patterns, we derive the surface unit cell in good accord with the parameters b and c for the lattice of the bulk crystal and derive information on the termination of the surface.

  9. Decomposing change in life expectancy

    DEFF Research Database (Denmark)

    Vaupel, James W.; Canudas Romo, Vladimir

    2003-01-01

    We extend Nathan Keyfitz's research on continuous change in life expectancy over time by presenting and proving a new formula for decomposing such change. The formula separates change in life expectancy over time into two terms. The first term captures the general effect of reduction in death rates...... at all ages, and the second term captures the effect of heterogeneity in the pace of improvement in mortality at different ages. We extend the formula to decompose change in life expectancy into age-specific and cause-specific components, and apply the methods to analyze changes in life expectancy...

  10. Characterization and simulation of fast neutron detectors based on surface-barrier VPE GaAs structures with polyethylene converter

    Science.gov (United States)

    Chernykh, A. V.; Chernykh, S. V.; Baryshnikov, F. M.; Didenko, S. I.; Burtebayev, N.; Britvich, G. I.; Kostin, M. Yu.; Chubenko, A. P.; Nassurlla, Marzhan; Nassurlla, Maulen; Kerimkulov, Zh.; Zholdybayev, T.; Glybin, Yu. N.; Sadykov, T. Kh.

    2016-12-01

    Fast neutron detectors with an active area of 80 mm2 based on surface-barrier VPE GaAs structures were fabricated and tested. Polyethylene with density of 0.90 g/cm3 was used as a converter layer. The recoil-proton surface-barrier sensor was fabricated on high purity VPE GaAs epilayers with a thickness of 50 μm. The neutron detection efficiency measured with a 241Am-Be source was 1.30 · 10-3 puls./neutr. for the PE converter thickness of 670 μm. The signal-to-gamma-background ratio was at the level of 50. Simulation of the detector characteristics with Geant4 toolkit has showed good correlation with the experimental data and allowed to estimate the maximal theoretical detection efficiency of the detector which is determined by the PE converter and equals to 1.37 · 10-3 puls./neutr. The difference between the measured and simulated values of the detection efficiency is due to the fact that the events with energies below 0.5 MeV were not taken into account during the measurements.

  11. The response of a fast phosphor screen scintillator (ZnO:Ga) to low energy ions (0-60 keV)

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Rey, D. [Centro de Micro-Analisis de Materiales, Universidad Autonoma de Madrid, C/ Faraday 3, Campus de Cantoblanco, E-28049 Madrid (Spain); Zurro, B.; Baciero, A.; Navarro, M. [Laboratorio Nacional de Fusion, Asociacion Euratom-CIEMAT, Av. Complutense 22, E-28040 Madrid (Spain); Rodriguez-Barquero, L. [Laboratorio de Metrologia de Radiaciones lonizantes, CIEMAT, Av. Complutense 22, E-28040 Madrid (Spain)

    2010-10-15

    ZnO:Ga is a promising, high time resolution candidate for use as a fast-ion-loss detector in TJ-II. We compare its ionoluminescence with that of the standard fast-ion-loss detector material, SrGa{sub 2}S{sub 4}:Eu (also known as TG-Green), when irradiated by H{sup +} ions with a range of energies E{<=}60 keV using a dedicated laboratory setup. It is found that ZnO:Ga is a reasonably good candidate for detecting low energy (E<60 keV) ions as it has excellent time resolution; however, its sensitivity is about 100 times lower than TG-Green, potentially limiting it to applications with high energy ion loss signals.

  12. Fast and simple preparation of 68Ga-citrate for routine clinical PET

    DEFF Research Database (Denmark)

    Nielsen, Karin M; Kaufmann, Jens; Mewis, Dennis

    2013-01-01

    cartridge (7.48 ± 1.23%) and in the waste vial (0.47 ± 0.28%). The radiochemical purity of the product determined by instant thin-layer chromatography was greater than 99%. The products have been proven to be sterile and pyrogen-free. Variations were made in several critical synthesis parameters......, and the results are presented herein. By eliminating the use of organic solvents, the previously required quality control testing of the final product by gas chromatography can be abandoned. This novel, high-yielding method allows for a more efficient synthesis of ⁶⁸Ga citrate with both shorter production time...

  13. Fast and simple one-step preparation of Ga-68 citrate for routine clinical PET

    DEFF Research Database (Denmark)

    Jensen, Svend B.; Nielsen, Karin M.; Mewis, Dennis

    2013-01-01

    , and the rest on the cation exchange cartridge (7.48 +/- 1.23 and in the waste vial (0.47 +/- 0.28. The radiochemical purity of the product determined by instant thin-layer chromatography was greater than 99 The products have been proven to be sterile and pyrogen-free. Variations were made in several critical...... synthesis parameters, and the results are presented herein. By eliminating the use of organic solvents, the previously required quality control testing of the final product by gas chromatography can be abandoned. This novel, high-yielding method allows for a more efficient synthesis of Ga-68 citrate...

  14. Fast and simple preparation of 68Ga-citrate for routine clinical PET

    DEFF Research Database (Denmark)

    Nielsen, Karin M; Kaufmann, Jens; Mewis, Dennis

    cartridge (7.48 ± 1.23%) and in the waste vial (0.47 ± 0.28%). The radiochemical purity of the product determined by instant thin-layer chromatography was greater than 99%. The products have been proven to be sterile and pyrogen-free. Variations were made in several critical synthesis parameters......, and the results are presented herein. By eliminating the use of organic solvents, the previously required quality control testing of the final product by gas chromatography can be abandoned. This novel, high-yielding method allows for a more efficient synthesis of ⁶⁸Ga citrate with both shorter production time...

  15. Self-Powered Solar-Blind Photodetector with Fast Response Based on Au/β-Ga2O3 Nanowires Array Film Schottky Junction.

    Science.gov (United States)

    Chen, Xing; Liu, Kewei; Zhang, Zhenzhong; Wang, Chunrui; Li, Binghui; Zhao, Haifeng; Zhao, Dongxu; Shen, Dezhen

    2016-02-17

    Because of the direct band gap of 4.9 eV, β-Ga2O3 has been considered as an ideal material for solar-blind photodetection without any bandgap tuning. Practical applications of the photodetectors require fast response speed, high signal-to-noise ratio, low energy consumption and low fabrication cost. Unfortunately, most reported β-Ga2O3-based photodetectors usually possess a relatively long response time. In addition, the β-Ga2O3 photodetectors based on bulk, the individual 1D nanostructure, and the film often suffer from the high cost, the low repeatability, and the relatively large dark current, respectively. In this paper, a Au/β-Ga2O3 nanowires array film vertical Schottky photodiode is successfully fabricated by a simple thermal partial oxidation process. The device exhibits a very low dark current of 10 pA at -30 V with a sharp cutoff at 270 nm. More interestingly, the 90-10% decay time of our device is only around 64 μs, which is much quicker than any other previously reported β-Ga2O3-based photodetectors. Besides, the self-powering, the excellent stability and the good reproducibility of Au/β-Ga2O3 nanowires array film photodetector are helpful to its commercialization and practical applications.

  16. Bounds for Completely Decomposable Jacobians

    CERN Document Server

    Duursma, Iwan

    2010-01-01

    A curve over the field of two elements with completely decomposable Jacobian is shown to have at most six rational points and genus at most 26. The bounds are sharp. The previous upper bound for the genus was 145. We also show that a curve over the field of $q$ elements with more than $q^{m/2}+1$ rational points has at least one Frobenius angle in the open interval $(\\pi/m,3\\pi/m)$. The proofs make use of the explicit formula method.

  17. Effect of the nitrogen incorporation and fast carrier dynamics in (In,Ga)AsN/GaP self-assembled quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Gauthier, J.-P.; Almosni, S.; Léger, Y.; Perrin, M.; Even, J.; Cornet, C., E-mail: charles.cornet@insa-rennes.fr; Durand, O. [UMR FOTON, CNRS, INSA-Rennes, F-35708 Rennes (France); Robert, C. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland); Balocchi, A.; Carrère, H.; Marie, X. [Université de Toulouse, INSA-CNRS-UPS, LPCNO, F-31077 Toulouse (France)

    2014-12-15

    We report on the structural and optical properties of (In,Ga)AsN self-assembled quantum dots grown on GaP (001) substrate. A comparison with nitrogen free (In,Ga)As system is presented, showing a clear modification of growth mechanisms and a significant shift of the photoluminescence spectrum. Low temperature carrier recombination dynamics is studied by time-resolved photoluminescence, highlighting a drastic reduction of the characteristic decay-time when nitrogen is incorporated in the quantum dots. Room temperature photoluminescence is observed at 840 nm. These results reveal the potential of (In,Ga)AsN as an efficient active medium monolithically integrated on Si for laser applications.

  18. FAST

    DEFF Research Database (Denmark)

    Zuidmeer-Jongejan, Laurian; Fernandez-Rivas, Montserrat; Poulsen, Lars K.

    2012-01-01

    ABSTRACT: The FAST project (Food Allergy Specific Immunotherapy) aims at the development of safe and effective treatment of food allergies, targeting prevalent, persistent and severe allergy to fish and peach. Classical allergen-specific immunotherapy (SIT), using subcutaneous injections with aqu......ABSTRACT: The FAST project (Food Allergy Specific Immunotherapy) aims at the development of safe and effective treatment of food allergies, targeting prevalent, persistent and severe allergy to fish and peach. Classical allergen-specific immunotherapy (SIT), using subcutaneous injections...... with aqueous food extracts may be effective but has proven to be accompanied by too many anaphylactic side-effects. FAST aims to develop a safe alternative by replacing food extracts with hypoallergenic recombinant major allergens as the active ingredients of SIT. Both severe fish and peach allergy are caused...... in depth serological and cellular immune analyses will be performed, allowing identification of novel biomarkers for monitoring treatment efficacy. FAST aims at improving the quality of life of food allergic patients by providing a safe and effective treatment that will significantly lower their threshold...

  19. Composing and decomposing data types

    DEFF Research Database (Denmark)

    Bahr, Patrick

    2014-01-01

    Wouter Swierstra's data types à la carte is a technique to modularise data type definitions in Haskell. We give an alternative implementation of data types à la carte that offers more flexibility in composing and decomposing data types. To achieve this, we refine the subtyping constraint, which...... is at the centre of data types à la carte. On the one hand this refinement is more general, allowing subtypings that intuitively should hold but were not derivable beforehand. This aspect of our implementation removes previous restrictions on how data types can be combined. On the other hand our refinement is more...... data types and to define extensible functions on data types in an ad hoc manner. The implementation makes essential use of closed type families in Haskell. The use of closed type families instead of type classes comes with a set of trade-offs, which we review in detail. Finally, we show that our...

  20. Ligand "Brackets" for Ga-Ga Bond.

    Science.gov (United States)

    Fedushkin, Igor L; Skatova, Alexandra A; Dodonov, Vladimir A; Yang, Xiao-Juan; Chudakova, Valentina A; Piskunov, Alexander V; Demeshko, Serhiy; Baranov, Evgeny V

    2016-09-06

    The reactivity of digallane (dpp-Bian)Ga-Ga(dpp-Bian) (1) (dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) toward acenaphthenequinone (AcQ), sulfur dioxide, and azobenzene was investigated. The reaction of 1 with AcQ in 1:1 molar ratio proceeds via two-electron reduction of AcQ to give (dpp-Bian)Ga(μ2-AcQ)Ga(dpp-Bian) (2), in which diolate [AcQ](2-) acts as "bracket" for the Ga-Ga bond. The interaction of 1 with AcQ in 1:2 molar ratio proceeds with an oxidation of the both dpp-Bian ligands as well as of the Ga-Ga bond to give (dpp-Bian)Ga(μ2-AcQ)2Ga(dpp-Bian) (3). At 330 K in toluene complex 2 decomposes to give compounds 3 and 1. The reaction of complex 2 with atmospheric oxygen results in oxidation of a Ga-Ga bond and affords (dpp-Bian)Ga(μ2-AcQ)(μ2-O)Ga(dpp-Bian) (4). The reaction of digallane 1 with SO2 produces, depending on the ratio (1:2 or 1:4), dithionites (dpp-Bian)Ga(μ2-O2S-SO2)Ga(dpp-Bian) (5) and (dpp-Bian)Ga(μ2-O2S-SO2)2Ga(dpp-Bian) (6). In compound 5 the Ga-Ga bond is preserved and supported by dithionite dianionic bracket. In compound 6 the gallium centers are bridged by two dithionite ligands. Both 5 and 6 consist of dpp-Bian radical anionic ligands. Four-electron reduction of azobenzene with 1 mol equiv of digallane 1 leads to complex (dpp-Bian)Ga(μ2-NPh)2Ga(dpp-Bian) (7). Paramagnetic compounds 2-7 were characterized by electron spin resonance spectroscopy, and their molecular structures were established by single-crystal X-ray analysis. Magnetic behavior of compounds 2, 5, and 6 was investigated by superconducting quantum interference device technique in the range of 2-295 K.

  1. Decomposability queueing and computer system applications

    CERN Document Server

    Courtois, P J

    1977-01-01

    Decomposability: Queueing and Computer System Applications presents a set of powerful methods for systems analysis. This 10-chapter text covers the theory of nearly completely decomposable systems upon which specific analytic methods are based.The first chapters deal with some of the basic elements of a theory of nearly completely decomposable stochastic matrices, including the Simon-Ando theorems and the perturbation theory. The succeeding chapters are devoted to the analysis of stochastic queuing networks that appear as a type of key model. These chapters also discuss congestion problems in

  2. Catalysts for decomposing ozone tail gas

    Institute of Scientific and Technical Information of China (English)

    LIU Chang-an; SUN De-zhi; WANG Hui; LI Wei

    2003-01-01

    The preparation of immobilizing-catalysts for decomposing ozone by using dipping method was studied. XRD, XPS and TEM were used to characterize the catalysts. The three kinds of catalysts were selected preferentially, and their catalytic activities were investigated. The results showed that the catalyst with activated carbon dipping acetate (active components are Mn: Cu = 3:2, active component proportion in catalyst is 15%, calcination temperature is 200℃ ) has the best catalytic activity for ozone decomposing. One gram of catalyst can decompose 17.6 g ozone at initial ozone concentration of 2.5 g/m3 and the residence time in reactor of 0.1 s. The experimental results also indicated that humidity of reaction system had negative effect on catalytic activity.

  3. Recursively arbitrarily vertex-decomposable suns

    Directory of Open Access Journals (Sweden)

    Olivier Baudon

    2011-01-01

    Full Text Available A graph \\(G = (V,E\\ is arbitrarily vertex decomposable if for any sequence \\(\\tau\\ of positive integers adding up to \\(|V|\\, there is a sequence of vertex-disjoint subsets of \\(V\\ whose orders are given by \\(\\tau\\, and which induce connected graphs. The aim of this paper is to study the recursive version of this problem on a special class of graphs called suns. This paper is a complement of [O. Baudon, F. Gilbert, M. Woźniak, Recursively arbitrarily vertex-decomposable graphs, research report, 2010].

  4. On decomposing languages defined by parallel devices

    DEFF Research Database (Denmark)

    Skyum, Sven

    1975-01-01

    In this paper we give a method for decomposing subclasses of different families of languages, into other possibly smaller families. This method can be used to produce languages not in a family by using known examples of languages not belonging to other families....

  5. Scalable Domain Decomposed Monte Carlo Particle Transport

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Matthew Joseph [Univ. of California, Davis, CA (United States)

    2013-12-05

    In this dissertation, we present the parallel algorithms necessary to run domain decomposed Monte Carlo particle transport on large numbers of processors (millions of processors). Previous algorithms were not scalable, and the parallel overhead became more computationally costly than the numerical simulation.

  6. On p-adic decomposable form inequalities

    NARCIS (Netherlands)

    Liu, Junjiang

    2015-01-01

    The main concern of this thesis is the number of the solutions $N_F(m)$ of Decomposable form inequalities $F(x) \\leq m$. In 2001, Thunder proved a conjecture of W.M. Schmidt, stating that, under suitable finiteness conditions, one has $N_F(m) \\ll m^{n/d}$ where the implicit constant depends only on

  7. On Decomposable Measures Induced by Metrics

    Directory of Open Access Journals (Sweden)

    Dong Qiu

    2012-01-01

    Full Text Available We prove that for a given normalized compact metric space it can induce a σ-max-superdecomposable measure, by constructing a Hausdorff pseudometric on its power set. We also prove that the restriction of this set function to the algebra of all measurable sets is a σ-max-decomposable measure. Finally we conclude this paper with two open problems.

  8. Decomposing Achievement Gaps among OECD Countries

    Science.gov (United States)

    Zhang, Liang; Lee, Kristen A.

    2011-01-01

    In this study, we use decomposition methods on PISA 2006 data to compare student academic performance across OECD countries. We first establish an empirical model to explain the variation in academic performance across individuals, and then use the Oaxaca-Blinder decomposition method to decompose the achievement gap between each of the OECD…

  9. The Ratio of Estimated Average Glucose to Fasting Plasma Glucose Level Is Superior to Glycated Albumin, Hemoglobin A1c, Fructosamine, and GA/A1c Ratio for Assessing β-Cell Function in Childhood Diabetes

    Directory of Open Access Journals (Sweden)

    Ji Eun Lee

    2014-01-01

    Full Text Available Objective. This study investigated the use of the estimated average glucose to fasting plasma glucose ratio (eAG/fPG ratio to screen for β-cell function in pediatric diabetes. Methods. Glycated hemoglobin (HbA1c, glycated albumin (GA, fructosamine, insulin, and C-peptide levels were measured. The ratio of GA to HbA1c (GA/A1c ratio was calculated, and the homeostasis model assessment of β-cell function (HOMA-β was determined. Results. Median values of C-peptide, insulin, and HOMA-β levels were significantly higher in patients with an increased eAG/fPG ratio than in those with a decreased eAG/fPG ratio. C-peptide and HOMA-β levels were more closely correlated with the eAG/fPG ratio than with GA, HbA1c, the GA/A1c ratio, and fructosamine. In contrast, body mass index was significantly associated with GA, GA/A1c ratio, and fructosamine, but not with the eAG/fPG ratio and HbA1c levels. To test the diagnostic accuracies of the eAG/fPG ratio for identifying HOMA-β > 30.0% in patients with type 2 diabetes, the area under the ROC curve of the eAG/fPG ratio was significantly larger than that of the GA/A1c ratio [0.877 (95% CI, 0.780–0.942 versus 0.775 (95% CI, 0.664–0.865, P=0.039]. Conclusions. A measurement of the eAG/fPG ratio may provide helpful information for assessing β-cell function in pediatric patients with diabetes.

  10. The ratio of estimated average glucose to fasting plasma glucose level is superior to glycated albumin, hemoglobin A1c, fructosamine, and GA/A1c ratio for assessing β-cell function in childhood diabetes.

    Science.gov (United States)

    Lee, Ji Eun; Lee, Ji Woo; Fujii, Tatsuyoshi; Fujii, Noriyoshi; Choi, Jong Weon

    2014-01-01

    This study investigated the use of the estimated average glucose to fasting plasma glucose ratio (eAG/fPG ratio) to screen for β-cell function in pediatric diabetes. Glycated hemoglobin (HbA1c), glycated albumin (GA), fructosamine, insulin, and C-peptide levels were measured. The ratio of GA to HbA1c (GA/A1c ratio) was calculated, and the homeostasis model assessment of β-cell function (HOMA-β) was determined. Median values of C-peptide, insulin, and HOMA-β levels were significantly higher in patients with an increased eAG/fPG ratio than in those with a decreased eAG/fPG ratio. C-peptide and HOMA-β levels were more closely correlated with the eAG/fPG ratio than with GA, HbA1c, the GA/A1c ratio, and fructosamine. In contrast, body mass index was significantly associated with GA, GA/A1c ratio, and fructosamine, but not with the eAG/fPG ratio and HbA1c levels. To test the diagnostic accuracies of the eAG/fPG ratio for identifying HOMA-β>30.0% in patients with type 2 diabetes, the area under the ROC curve of the eAG/fPG ratio was significantly larger than that of the GA/A1c ratio [0.877 (95% CI, 0.780-0.942) versus 0.775 (95% CI, 0.664-0.865), P=0.039]. A measurement of the eAG/fPG ratio may provide helpful information for assessing β-cell function in pediatric patients with diabetes.

  11. Decomposed Implicit Models of Piecewise - Linear Networks

    Directory of Open Access Journals (Sweden)

    J. Brzobohaty

    1992-05-01

    Full Text Available The general matrix form of the implicit description of a piecewise-linear (PWL network and the symbolic block diagram of the corresponding circuit model are proposed. Their decomposed forms enable us to determine quite separately the existence of the individual breakpoints of the resultant PWL characteristic and their coordinates using independent network parameters. For the two-diode and three-diode cases all the attainable types of the PWL characteristic are introduced.

  12. Recursively arbitrarily vertex-decomposable graphs

    Directory of Open Access Journals (Sweden)

    Olivier Baudon

    2012-01-01

    Full Text Available A graph \\(G = (V;E\\ is arbitrarily vertex decomposable if for any sequence \\(\\tau\\ of positive integers adding up to \\(|V|\\, there is a sequence of vertex-disjoint subsets of \\(V\\ whose orders are given by \\(\\tau\\, and which induce connected graphs. The main aim of this paper is to study the recursive version of this problem. We present a solution for trees, suns, and partially for a class of 2-connected graphs called balloons.

  13. Combined experimental and theoretical study of fast atom diffraction on the β2(2×4) reconstructed GaAs(001) surface

    Science.gov (United States)

    Debiossac, M.; Zugarramurdi, A.; Khemliche, H.; Roncin, P.; Borisov, A. G.; Momeni, A.; Atkinson, P.; Eddrief, M.; Finocchi, F.; Etgens, V. H.

    2014-10-01

    A grazing incidence fast atom diffraction (GIFAD or FAD) setup, installed on a molecular beam epitaxy chamber, has been used to characterize the β2(2×4) reconstruction of a GaAs(001) surface at 530∘C under an As4 overpressure. Using a 400-eV 4He beam, high-resolution diffraction patterns with up to eighty well-resolved diffraction orders are observed simultaneously, providing a detailed fingerprint of the surface structure. Experimental diffraction data are in good agreement with results from quantum scattering calculations based on an ab initio projectile-surface interaction potential. Along with exact calculations, we show that a straightforward semiclassical analysis allows the features of the diffraction chart to be linked to the main characteristics of the surface reconstruction topography. Our results demonstrate that GIFAD is a technique suitable for measuring in situ the subtle details of complex surface reconstructions. We have performed measurements at very small incidence angles, where the kinetic energy of the projectile motion perpendicular to the surface can be reduced to less than 1 meV. This allowed the depth of the attractive van der Waals potential well to be estimated as -8.7 meV in very good agreement with results reported in literature.

  14. A new construction for vertex decomposable graphs

    Directory of Open Access Journals (Sweden)

    Nasser Hajisharifi

    2016-09-01

    Full Text Available Let G be a finite simple graph on the vertex set V(G and let S⊆V(G. Adding a whisker to G at x means adding a new vertex y and edge xy to G where x∈V(G. The graph G∪W(S is obtained from G by adding a whisker to every vertex of S. We prove that if G∖S is either a graph with no chordless cycle of length other than 3 or 5, chordal graph or C5, then G∪W(S is a vertex decomposable graph.

  15. Multiple Decomposability of Probabilities on Contractible Locally Compact Groups

    Indian Academy of Sciences (India)

    Wilfried Hazod; Katrin Kosfeld

    2013-05-01

    Operator decomposable probabilities on vector spaces – generalizing (semi-)stable and self-decomposable laws – are well known. Here we are concerned with multiple decomposability on locally compact groups. In fact, as it turned out that contraction properties play an essential role, throughout we concentrate on contractible locally compact groups.

  16. Challenges in Decomposing Encodings of Verification Problems

    Directory of Open Access Journals (Sweden)

    Peter Schrammel

    2016-07-01

    Full Text Available Modern program verifiers use logic-based encodings of the verification problem that are discharged by a back end reasoning engine. However, instances of such encodings for large programs can quickly overwhelm these back end solvers. Hence, we need techniques to make the solving process scale to large systems, such as partitioning (divide-and-conquer and abstraction. In recent work, we showed how decomposing the formula encoding of a termination analysis can significantly increase efficiency. The analysis generates a sequence of logical formulas with existentially quantified predicates that are solved by a synthesis-based program analysis engine. However, decomposition introduces abstractions in addition to those required for finding the unknown predicates in the formula, and can hence deteriorate precision. We discuss the challenges associated with such decompositions and their interdependencies with the solving process.

  17. Supporting Knowledge Transfer through Decomposable Reasoning Artifacts

    Energy Technology Data Exchange (ETDEWEB)

    Pike, William A.; May, Richard A.; Turner, Alan E.

    2007-01-03

    Technology to support knowledge transfer and cooperative inquiry must offer its users the ability to effectively interpret knowledge structures produced by collaborators. Communicating the reasoning processes that underlie a finding is one method for enhancing interpretation, and can result in more effective evaluation and application of shared knowledge. In knowledge management tools, interpretation is aided by creating knowledge artifacts that can expose their provenance to scrutiny and that can be transformed into diverse representations that suit their consumers’ perspectives and preferences. We outline the information management needs of inquiring communities characterized by hypothesis generation tasks, and propose a model for communication, based in theories of hermeneutics, semiotics, and abduction, in which knowledge structures can be decomposed into the lower-level reasoning artifacts that produced them. We then present a proof-of-concept implementation for an environment to support the capture and communication of analytic products, with emphasis on the domain of intelligence analysis.

  18. Decomposability and mental representation of French verbs

    Directory of Open Access Journals (Sweden)

    Gustavo Lopez Estivalet

    2015-01-01

    Full Text Available In French, regardless of stem regularity, inflectional verbal suffixes are extremely regular and paradigmatic. Considering the complexity of the French verbal system, we argue that all French verbs are polymorphemic forms that are decomposed during visual recognition independently of their stem regularity. We conducted a behavioural experiment in which we manipulated the surface and cumulative frequencies of verbal inflected forms and asked participants to perform a visual lexical decision task. We tested four types of verbs with respect to their stem variants: a. fully regular (parler ‘to speak’, [parl-]; b. phonological change e/E verbs with orthographic markers (répéter ‘to repeat’, [répét-] and [répèt-]; c. phonological change o/O verbs without orthographic markers (adorer ‘to adore’, [ador-] and [adOr-]; and d. idiosyncratic (boire ‘to drink’, [boi-] and [buv-]. For each type of verb, we contrasted four conditions, forms with high and low surface frequencies and forms with high and low cumulative frequencies. Our results showed a significant cumulative frequency effect for the fully regular and idiosyncratic verbs, indicating that different stems within idiosyncratic verbs (such as [boi-] and [buv-] have distinct representations in the mental lexicon as different fully regular verbs. For the phonological change verbs, we found a significant cumulative frequency effect only when considering the two forms of the stem together ([répét-] and [répèt-], suggesting that they share a single abstract and underspecified phonological representation. Our results also revealed a significant surface frequency effect for all types of verbs, which may reflect the recombination of the stem lexical representation with the functional information of the suffixes. Overall, these results indicate that all inflected verbal forms in French are decomposed during visual recognition and that this process could be due to the regularities of

  19. DCMDSM: a DICOM decomposed storage model.

    Science.gov (United States)

    Savaris, Alexandre; Härder, Theo; von Wangenheim, Aldo

    2014-01-01

    To design, build, and evaluate a storage model able to manage heterogeneous digital imaging and communications in medicine (DICOM) images. The model must be simple, but flexible enough to accommodate variable content without structural modifications; must be effective on answering query/retrieval operations according to the DICOM standard; and must provide performance gains on querying/retrieving content to justify its adoption by image-related projects. The proposal adapts the original decomposed storage model, incorporating structural and organizational characteristics present in DICOM image files. Tag values are stored according to their data types/domains, in a schema built on top of a standard relational database management system (RDBMS). Evaluation includes storing heterogeneous DICOM images, querying metadata using a variable number of predicates, and retrieving full-content images for different hierarchical levels. When compared to a well established DICOM image archive, the proposal is 0.6-7.2 times slower in storing content; however, in querying individual tags, it is about 48.0% faster. In querying groups of tags, DICOM decomposed storage model (DCMDSM) is outperformed in scenarios with a large number of tags and low selectivity (being 66.5% slower); however, when the number of tags is balanced with better selectivity predicates, the performance gains are up to 79.1%. In executing full-content retrieval, in turn, the proposal is about 48.3% faster. DCMDSM is a model built for the storage of heterogeneous DICOM content, based on a straightforward database design. The results obtained through its evaluation attest its suitability as a storage layer for projects where DICOM images are stored once, and queried/retrieved whenever necessary. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  20. Decomposing the misery index: A dynamic approach

    Directory of Open Access Journals (Sweden)

    Ivan K. Cohen

    2014-12-01

    Full Text Available The misery index (the unweighted sum of unemployment and inflation rates was probably the first attempt to develop a single statistic to measure the level of a population’s economic malaise. In this letter, we develop a dynamic approach to decompose the misery index using two basic relations of modern macroeconomics: the expectations-augmented Phillips curve and Okun’s law. Our reformulation of the misery index is closer in spirit to Okun’s idea. However, we are able to offer an improved version of the index, mainly based on output and unemployment. Specifically, this new Okun’s index measures the level of economic discomfort as a function of three key factors: (1 the misery index in the previous period; (2 the output gap in growth rate terms; and (3 cyclical unemployment. This dynamic approach differs substantially from the standard one utilised to develop the misery index, and allow us to obtain an index with five main interesting features: (1 it focuses on output, unemployment and inflation; (2 it considers only objective variables; (3 it allows a distinction between short-run and long-run phenomena; (4 it places more importance on output and unemployment rather than inflation; and (5 it weights recessions more than expansions.

  1. Wishart distributions for decomposable covariance graph models

    CERN Document Server

    Khare, Kshitij; 10.1214/10-AOS841

    2011-01-01

    Gaussian covariance graph models encode marginal independence among the components of a multivariate random vector by means of a graph $G$. These models are distinctly different from the traditional concentration graph models (often also referred to as Gaussian graphical models or covariance selection models) since the zeros in the parameter are now reflected in the covariance matrix $\\Sigma$, as compared to the concentration matrix $\\Omega =\\Sigma^{-1}$. The parameter space of interest for covariance graph models is the cone $P_G$ of positive definite matrices with fixed zeros corresponding to the missing edges of $G$. As in Letac and Massam [Ann. Statist. 35 (2007) 1278--1323], we consider the case where $G$ is decomposable. In this paper, we construct on the cone $P_G$ a family of Wishart distributions which serve a similar purpose in the covariance graph setting as those constructed by Letac and Massam [Ann. Statist. 35 (2007) 1278--1323] and Dawid and Lauritzen [Ann. Statist. 21 (1993) 1272--1317] do in ...

  2. Integrated boiler, superheater, and decomposer for sulfuric acid decomposition

    Science.gov (United States)

    Moore, Robert; Pickard, Paul S.; Parma, Jr., Edward J.; Vernon, Milton E.; Gelbard, Fred; Lenard, Roger X.

    2010-01-12

    A method and apparatus, constructed of ceramics and other corrosion resistant materials, for decomposing sulfuric acid into sulfur dioxide, oxygen and water using an integrated boiler, superheater, and decomposer unit comprising a bayonet-type, dual-tube, counter-flow heat exchanger with a catalytic insert and a central baffle to increase recuperation efficiency.

  3. Quantum dynamical semigroups and non-decomposable positive maps

    Energy Technology Data Exchange (ETDEWEB)

    Benatti, Fabio; Floreanini, Roberto; Piani, Marco

    2004-06-07

    We study dynamical semigroups of positive, but not completely positive maps on finite-dimensional bipartite systems and analyze properties of their generators in relation to non-decomposability and bound-entanglement. An example of non-decomposable semigroup leading to a (4x4)-dimensional bound-entangled density matrix is explicitly obtained.

  4. 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.

  5. MOVPE of n-doped GaAs and modulation doped GaAs/AlGaAs nanowires

    Science.gov (United States)

    Sladek, K.; Klinger, V.; Wensorra, J.; Akabori, M.; Hardtdegen, H.; Grützmacher, D.

    2010-02-01

    Two different fabrication approaches were compared to obtain conductive GaAs nanowires: on one hand by modulation doping of GaAs/AlGaAs core/shell nanowires, on the other hand by Si-doping of GaAs nanowires. Modulation doped GaAs/AlGaAs core-shell nanowires were grown by selective area metal organic vapor phase epitaxy (MOVPE) on GaAs (1 1 1) substrates. The influences of growth parameters and mask design on aspect ratio of the core structures were investigated. The specialty of this study was that the growth mode was switched from vertical GaAs wire growth to the AlGaAs conformal shell overgrowth by intentionally changing the growth chemistry from the use of a more stable group III source - trimethylgallium (TMGa) to more easily decomposed sources - the alternative sources triethylgallium (TEGa) and dimethylethylaminealane (DMEAAl). It was found that the diameter and length of the core structures strongly depend on the arsenic partial pressure and growth temperature as well as mask design. The uniformity of shell growth is also influenced by the mask design. Additionally an alternative approach for the production of conductive GaAs nanowires was under study. To this end, the influence of Si-doping on GaAs core growth was investigated. It was found that doping has a detrimental impact on growth morphology leading to an undesirable enhanced growth rate on the nanowire side facets.

  6. Patterned growth of InGaN/GaN quantum wells on freestanding GaN grating by molecular beam epitaxy

    OpenAIRE

    Wang Yongjin; Hu Fangren; Hane Kazuhiro

    2011-01-01

    Abstract We report here the epitaxial growth of InGaN/GaN quantum wells on freestanding GaN gratings by molecular beam epitaxy (MBE). Various GaN gratings are defined by electron beam lithography and realized on GaN-on-silicon substrate by fast atom beam etching. Silicon substrate beneath GaN grating region is removed from the backside to form freestanding GaN gratings, and the patterned growth is subsequently performed on the prepared GaN template by MBE. The selective growth takes place wit...

  7. Fluidic Integration of Nanophotonic Devices Using Decomposable Polymers

    CERN Document Server

    Hosseini, Ehsan Shah; Kohl, Paul; Adibi, Ali

    2015-01-01

    Polynorbornene-based decomposable polymer which can be patterned with ultraviolet or electron-beam radiation is used to create micrometer-scale fluidic channels. Silicon nitride substrates are used to fabricate nanophotonic wavegide and resonators operating in the visible range of the spectrum. Fluidic channels generated by thermally decomposing the polymer through the oxide cladding is used to deliver ultra-small amounts of florescent samples to the optical sensors.

  8. Particle-based Full-band Approach for Fast Simulation of Charge Transport in Si, GaAs, and InP

    Directory of Open Access Journals (Sweden)

    Marco Saraniti

    2002-01-01

    Full Text Available We discuss the application of the fullband cellular automaton (CA method for the simulation of charge transport in several semiconductors. Basing the selection of the state after scattering on simple look-up tables, the approach is physically equivalent to the full band Monte Carlo (MC approach but is much faster. Furthermore, the structure of the pre-tabulated transition probabilities naturally allows for an extension of the model to fully anisotropic scattering without additional computational burden. Simulation results of transport of electrons and holes in several materials are discussed, with particular emphasis on the transient response of photo-generated carriers in InP and GaAs. Finally, a discussion on parallel algorithms is presented, for the implementation of the code on workstation clusters.

  9. Ultra-fast charge carrier dynamics across the spectrum of an optical gain media based on InAs/AlGaInAs/InP quantum dots

    Directory of Open Access Journals (Sweden)

    I. Khanonkin

    2017-03-01

    Full Text Available The charge carrier dynamics of improved InP-based InAs/AlGaInAs quantum dot (QD semiconductor optical amplifiers are examined employing the multi-wavelength ultrafast pump-probe measurement technique. The transient transmission response of the continuous wave probe shows interesting dynamical processes during the initial 2-3 ps after the pump pulse, when carriers originating from two photon absorption contribute the least to the recovery. The effects of optical excitations and electrical bias levels on the recovery dynamics of the gain in energetically different QDs are quantified and discussed. The experimental observations are validated qualitatively using a comprehensive finite-difference time-domain model by recording the time evolution of the charge carriers in the QDs ensemble following the pulse.

  10. Decomposing the sales promotion bump with store data

    NARCIS (Netherlands)

    van Heerde, H.J.; Leeflang, P.S.H.; Wittink, D.R.

    2004-01-01

    Sales promotions generate substantial short-term sales increases. To determine whether the sales promotion bump is truly beneficial from a managerial perspective, we propose a system of store-level regression models that decomposes the sales promotion bump into three parts: cross-brand effects (seco

  11. Catalytic activities of zeolite compounds for decomposing aqueous ozone.

    Science.gov (United States)

    Kusuda, Ai; Kitayama, Mikito; Ohta, Yoshio

    2013-12-01

    The advanced oxidation process (AOP), chemical oxidation using aqueous ozone in the presence of appropriate catalysts to generate highly reactive oxygen species, offers an attractive option for removing poorly biodegradable pollutants. Using the commercial zeolite powders with various Si/Al ratios and crystal structures, their catalytic activities for decomposing aqueous ozone were evaluated by continuously flowing ozone to water containing the zeolite powders. The hydrophilic zeolites (low Si/Al ratio) with alkali cations in the crystal structures were found to possess high catalytic activity for decomposing aqueous ozone. The hydrophobic zeolite compounds (high Si/Al ratio) were found to absorb ozone very well, but to have no catalytic activity for decomposing aqueous ozone. Their catalytic activities were also evaluated by using the fixed bed column method. When alkali cations were removed by acid rinsing or substituted by alkali-earth cations, the catalytic activities was significantly deteriorated. These results suggest that the metal cations on the crystal surface of the hydrophilic zeolite would play a key role for catalytic activity for decomposing aqueous ozone.

  12. A (de)composable theory of rhythm perception

    NARCIS (Netherlands)

    Desain, P.

    1992-01-01

    A definition is given of expectancy of events projected into the future by a complex temporal sequence. The definition can be decomposed into basic expectancy components projected by each time interval implicit in the sequence. A preliminary formulation of these basic curves is proposed and the

  13. Natural manganese deposits as catalyst for decomposing hydrogen peroxide

    NARCIS (Netherlands)

    Knol, A.H.; Lekkerkerker-Teunissen, K.; Van Dijk, J.C.

    2015-01-01

    Drinking water companies (are intending to) implement advanced oxidation processes (AOP) in their treatment schemes to increase the barrier against organic micropollutants (OMPs). It is necessary to decompose the excessive hydrogen peroxide after applying AOP to avoid negative effects in the

  14. Decomposing the sales promotion bump with store data

    NARCIS (Netherlands)

    van Heerde, H.J.; Leeflang, P.S.H.; Wittink, D.R.

    2004-01-01

    Sales promotions generate substantial short-term sales increases. To determine whether the sales promotion bump is truly beneficial from a managerial perspective, we propose a system of store-level regression models that decomposes the sales promotion bump into three parts: cross-brand effects

  15. [Allelopathy of decomposing pepper stalk on pepper growth].

    Science.gov (United States)

    Hou, Yongxia; Zhou, Baoli; Wu, Xiaoling; Fu, Yawen; Wang, Yueying

    2006-04-01

    With decomposing pepper stalk as test material, this paper studied its allelopathy on the growth of pepper plants. The results showed that after 60 days of decomposition, the decomposed pepper stalk could decrease the plant height, stem diameter, dry weights of above-and underground biomass, leaf area, and chlorophyll content of pepper plants by 0.0374 - 0.0646, 0.0020 - 0.0097, 0.0050 - 0.0355 and 0.0916 - 0.3584, 0.0016 - 0.0251, and 0.0043 - 0.0242 respectively. These inhibitory effects were enhanced after 120 days of decomposition, but the difference with CK was not significant. The root vigor and its SOD, POD and CAT activities of pepper plants were decreased, while the MDA content and relative conductivity were increased with the increasing concentration of decomposed pepper stalk and with the prolong of treating time. The allelopathic effects of decomposed pepper stalk on the physiological indices of pepper root activity ranged from 0.0163 to 0.6507, which was significantly higher than that of plant growth index.

  16. Decomposing preference shifts for meat and fish in the Netherlands.

    NARCIS (Netherlands)

    Mangen, M.J.J.; Burrell, A.M.

    2001-01-01

    The changing preferences of Dutch consumers for meat and fish are investigated using a switching almost ideal demand system. Structural change in demand between January 1994 and May 1998 is decomposed into underlying trends, temporarily irreversible preference shifts triggered by the BSE crisis of

  17. A (de)composable theory of rhythm perception

    NARCIS (Netherlands)

    Desain, P.

    1992-01-01

    A definition is given of expectancy of events projected into the future by a complex temporal sequence. The definition can be decomposed into basic expectancy components projected by each time interval implicit in the sequence. A preliminary formulation of these basic curves is proposed and the (de)

  18. Image processing for grazing incidence fast atom diffraction: the $\\beta_2$(2x4) reconstruction of the GaAs(001) surface

    CERN Document Server

    Debiossac, Maxime

    2015-01-01

    Grazing incidence fast atom diffraction (GIFAD, or FAD) has developed as a very sensitive technique most suited for well ordered crystalline surfaces. Such high quality surfaces are routinely fabricated in molecular beam epitaxy (MBE) chamber and a GIFAD setup has been installed allowing in situ operation. Focusing here on static condition, i.e. before or after the growth process, the paper describes in details the few steps needed to measure the relative intensities of the diffraction spots. Care is taken to outline the underlying physical assumptions.

  19. Spinors, strings, integrable models, and decomposed Yang-Mills theory

    Science.gov (United States)

    Ioannidou, Theodora; Jiang, Ying; Niemi, Antti J.

    2014-07-01

    This paper deals with various interrelations between strings and surfaces in three-dimensional ambient space, two-dimensional integrable models, and two-dimensional and four-dimensional decomposed SU(2) Yang-Mills theories. Initially, a spinor version of the Frenet equation is introduced in order to describe the differential geometry of static three-dimensional stringlike structures. Then its relation to the structure of the su_(2) Lie algebra valued Maurer-Cartan one-form is presented, while by introducing time evolution of the string a Lax pair is obtained, as an integrability condition. In addition, it is shown how the Lax pair of the integrable nonlinear Schrödinger equation becomes embedded into the Lax pair of the time extended spinor Frenet equation, and it is described how a spinor-based projection operator formalism can be used to construct the conserved quantities, in the case of the nonlinear Schrödinger equation. Then the Lax pair structure of the time extended spinor Frenet equation is related to properties of flat connections in a two-dimensional decomposed SU(2) Yang-Mills theory. In addition, the connection between the decomposed Yang-Mills and the Gauß-Codazzi equation that describes surfaces in three-dimensional ambient space is presented. In that context the relation between isothermic surfaces and integrable models is discussed. Finally, the utility of the Cartan approach to differential geometry is considered. In particular, the similarities between the Cartan formalism and the structure of both two-dimensional and four-dimensional decomposed SU(2) Yang-Mills theories are discussed, while the description of two-dimensional integrable models as embedded structures in the four-dimensional decomposed SU(2) Yang-Mills theory are presented.

  20. First-principles and thermodynamic analysis of trimethylgallium (TMG) decomposition during MOVPE growth of GaN

    Science.gov (United States)

    Sekiguchi, K.; Shirakawa, H.; Yamamoto, Y.; Araidai, M.; Kangawa, Y.; Kakimoto, K.; Shiraishi, K.

    2017-06-01

    We analyzed the decomposition mechanisms of trimethylgallium (TMG) used for the gallium source of GaN fabrication based on first-principles calculations and thermodynamic analysis. We considered two conditions. One condition is under the total pressure of 1 atm and the other one is under metal organic vapor phase epitaxy (MOVPE) growth of GaN. Our calculated results show that H2 is indispensable for TMG decomposition under both conditions. In GaN MOVPE, TMG with H2 spontaneously decomposes into Ga(CH3) and Ga(CH3) decomposes into Ga atom gas when temperature is higher than 440 K. From these calculations, we confirmed that TMG surely becomes Ga atom gas near the GaN substrate surfaces.

  1. Effects of NH3 Flow Rate During AlGaN Barrier Layer Growth on the Material Properties of AlGaN/GaN HEMT Heterostructure

    Science.gov (United States)

    Lumbantoruan, Franky J.; Wong, Yuen-Yee; Huang, Wei-Ching; Yu, Hung-Wei; Chang, Edward-Yi

    2017-10-01

    NH3 flow rate during AlGaN barrier layer growth not only affects the growth efficiency and surface morphology as a result of parasitic reactions but also influences the concentration of carbon impurity in the AlGaN barrier. Carbon, which decomposes from metal precursors, plays a role in electron compensation for AlGaN/GaN HEMT. No 2-dimensional electron gas (2-DEG) was detected in the AlGaN/GaN structure if grown with 0.5 slm of NH3 due to the presence of higher carbon impurity (2.6 × 1019 cm-2). When the NH3 flow rate increased to 6.0 slm, the carbon impurity reduced to 2.10 × 1018 atom cm-3 and the 2 DEG electron density recovered to 9.57 × 1012 cm-2.

  2. The -250G>A promoter variant in hepatic lipase associates with elevated fasting serum high-density lipoprotein cholesterol modulated by interaction with physical activity in a study of 16,156 Danish subjects

    DEFF Research Database (Denmark)

    Grarup, Niels; Andreasen, Camilla H; Andersen, Mette K;

    2008-01-01

    of variants in LIPC on metabolic traits and type 2 diabetes in a large sample of Danes. Because behavioral factors influence hepatic lipase activity, we furthermore examined possible gene-environment interactions in the population-based Inter99 study. DESIGN: The LIPC -250G>A (rs2070895) variant was genotyped...... Treatment in People with Screen Detected Diabetes in Primary Care study [0.038 mmol/liter per allele (95% CI 0.024-0.053); P = 2 x 10(-7)). The allelic effect on HDL-c was modulated by interaction with self-reported physical activity (P(interaction) = 0.002) because vigorous physically active homozygous A......-allele carriers had a 0.30 mmol/liter (95% CI 0.22-0.37) increase in HDL-c compared with homozygous G-allele carriers. CONCLUSIONS: We validate the association of LIPC promoter variation with fasting serum HDL-c and present data supporting an interaction with physical activity implying an increased effect on HDL...

  3. Decomposable medium conditions in four-dimensional representation

    CERN Document Server

    Lindell, Ismo V; Favaro, Alberto

    2011-01-01

    The well-known TE/TM decomposition of time-harmonic electromagnetic fields in uniaxial anisotropic media is generalized in terms of four-dimensional differential-form formalism by requiring that the field two-form satisfies an orthogonality condition with respect to two given bivectors. Conditions for the electromagnetic medium in which such a decomposition is possible are derived and found to define three subclasses of media. It is shown that the previously known classes of generalized Q-media and generalized P-media are particular cases of the proposed decomposable media (DCM) associated to a quadratic equation for the medium dyadic. As a novel solution, another class of special decomposable media (SDCM) is defined by a linear dyadic equation. The paper further discusses the properties of medium dyadics and plane-wave propagation in all the identified cases of DCM and SDCM.

  4. Decomposing Income Inequality and Policy Implications in Rural China

    Institute of Scientific and Technical Information of China (English)

    Lerong Yu; Renfu Luo; Linxiu Zhang

    2007-01-01

    Using village data from samples covering 6 provinces, 36 counties and 216 townships, the income inequalities within and between townships in rural China are assessed. The Theil index and the mean logarithmic deviation methods enable us to test income inequality at the township level, and to decompose it into intra-regional and inter-regional at county and provincial levels. In the present paper, we also decompose income inequalities between and within the nationally designated poor counties (NDPC). The results show that approximately two-thirds of the income inequality in rural China would be eliminated if measures and policies were targeted at the county level. This study also confirms the rationale that China's poverty alleviation strategy of focusing on poor counties based on the inequalities between NDPC and non-NDPC accounts for the most inter-province inequality.

  5. Decomposing Oriented Graphs into Six Locally Irregular Oriented Graphs

    DEFF Research Database (Denmark)

    Bensmail, Julien; Renault, Gabriel

    2016-01-01

    An undirected graph G is locally irregular if every two of its adjacent vertices have distinct degrees. We say that G is decomposable into k locally irregular graphs if there exists a partition E1∪E2∪⋯∪Ek of the edge set E(G) such that each Ei induces a locally irregular graph. It was recently co...

  6. Domain decomposed preconditioners with Krylov subspace methods as subdomain solvers

    Energy Technology Data Exchange (ETDEWEB)

    Pernice, M. [Univ. of Utah, Salt Lake City, UT (United States)

    1994-12-31

    Domain decomposed preconditioners for nonsymmetric partial differential equations typically require the solution of problems on the subdomains. Most implementations employ exact solvers to obtain these solutions. Consequently work and storage requirements for the subdomain problems grow rapidly with the size of the subdomain problems. Subdomain solves constitute the single largest computational cost of a domain decomposed preconditioner, and improving the efficiency of this phase of the computation will have a significant impact on the performance of the overall method. The small local memory available on the nodes of most message-passing multicomputers motivates consideration of the use of an iterative method for solving subdomain problems. For large-scale systems of equations that are derived from three-dimensional problems, memory considerations alone may dictate the need for using iterative methods for the subdomain problems. In addition to reduced storage requirements, use of an iterative solver on the subdomains allows flexibility in specifying the accuracy of the subdomain solutions. Substantial savings in solution time is possible if the quality of the domain decomposed preconditioner is not degraded too much by relaxing the accuracy of the subdomain solutions. While some work in this direction has been conducted for symmetric problems, similar studies for nonsymmetric problems appear not to have been pursued. This work represents a first step in this direction, and explores the effectiveness of performing subdomain solves using several transpose-free Krylov subspace methods, GMRES, transpose-free QMR, CGS, and a smoothed version of CGS. Depending on the difficulty of the subdomain problem and the convergence tolerance used, a reduction in solution time is possible in addition to the reduced memory requirements. The domain decomposed preconditioner is a Schur complement method in which the interface operators are approximated using interface probing.

  7. Fast chemical bath deposition of Zn(O,S) buffer layers for Cu(In,Ga)Se{sub 2} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Buffiere, M., E-mail: Marie.Buffiere@cnrs-imn.fr; Harel, S.; Arzel, L.; Deudon, C.; Barreau, N.; Kessler, J.

    2011-08-31

    In order to decrease the deposition time of chemical bath deposited (CBD) Zn(O,S) buffer layers in CIGSe solar cell, the alternative CBD route using H{sub 2}O{sub 2} as additional oxygen source has been investigated. The morphology and the optical properties of the Zn(O,S) thin films grown with and without additive have been compared through scanning electron microscopy (SEM) observations and UV-visible transmission T({lambda}) and reflectivity R({lambda}) measurements, respectively. It is observed that deposition time shorter than 5 min is sufficient to achieve films with similar properties to those deposited following the standard recipe in 15 min. The characteristics of CIGSe/Zn(O,S) structures for which the Zn(O,S) growth has been interrupted after different bath immersion durations have been investigated by XPS measurements. The evolution of the In3d and Zn2p{sub 3/2} signals reveals that after 2 min of deposition, the Zn(O,S) layer grown by the alternative process completely covers the CIGSe and suggests that the increase of the Zn(O,S) growth rate is most probably due to the acceleration of cluster mechanism growth. A comparative study of devices buffered with the so-called fast and standard Zn(O,S) shows similar efficiencies in either case after light soaking.

  8. Atomic-batched tensor decomposed two-electron repulsion integrals

    Science.gov (United States)

    Schmitz, Gunnar; Madsen, Niels Kristian; Christiansen, Ove

    2017-04-01

    We present a new integral format for 4-index electron repulsion integrals, in which several strategies like the Resolution-of-the-Identity (RI) approximation and other more general tensor-decomposition techniques are combined with an atomic batching scheme. The 3-index RI integral tensor is divided into sub-tensors defined by atom pairs on which we perform an accelerated decomposition to the canonical product (CP) format. In a first step, the RI integrals are decomposed to a high-rank CP-like format by repeated singular value decompositions followed by a rank reduction, which uses a Tucker decomposition as an intermediate step to lower the prefactor of the algorithm. After decomposing the RI sub-tensors (within the Coulomb metric), they can be reassembled to the full decomposed tensor (RC approach) or the atomic batched format can be maintained (ABC approach). In the first case, the integrals are very similar to the well-known tensor hypercontraction integral format, which gained some attraction in recent years since it allows for quartic scaling implementations of MP2 and some coupled cluster methods. On the MP2 level, the RC and ABC approaches are compared concerning efficiency and storage requirements. Furthermore, the overall accuracy of this approach is assessed. Initial test calculations show a good accuracy and that it is not limited to small systems.

  9. $Profiler$ - A Fast and Versatile New Program for Decomposing Galaxy Light Profiles

    CERN Document Server

    Ciambur, Bogdan C

    2016-01-01

    I introduce $Profiler$, a new, user-friendly program written in $Python$ and designed to analyse the radial surface brightness profiles of galaxies. With an intuitive graphical user interface, $Profiler$ can accurately model a wide range of galaxies and galaxy components, such as elliptical galaxies, the bulges of spiral and lenticular galaxies, nuclear sources, discs, bars, rings, spiral arms, etc., with a variety of parametric functions routinely employed in the field (S\\'ersic, core-S\\'ersic, exponential, Gaussian, Moffat and Ferrers). In addition to these, $Profiler$ can employ the broken exponential model (relevant for disc truncations or antitruncations) and two special cases of the edge-on disc model: namely along the major axis (in the disc plane) and along the minor axis (perpendicular to the disc plane). $Profiler$ is optimised to work with galaxy light profiles obtained from isophotal measurements which capture radial gradients in the ellipticity, position angle and Fourier harmonic profiles of the...

  10. Materials study supporting thermochemical hydrogen cycle sulfuric acid decomposer design

    Science.gov (United States)

    Peck, Michael S.

    Increasing global climate change has been driven by greenhouse gases emissions originating from the combustion of fossil fuels. Clean burning hydrogen has the potential to replace much of the fossil fuels used today reducing the amount of greenhouse gases released into the atmosphere. The sulfur iodine and hybrid sulfur thermochemical cycles coupled with high temperature heat from advanced nuclear reactors have shown promise for economical large-scale hydrogen fuel stock production. Both of these cycles employ a step to decompose sulfuric acid to sulfur dioxide. This decomposition step occurs at high temperatures in the range of 825°C to 926°C dependent on the catalysis used. Successful commercial implementation of these technologies is dependent upon the development of suitable materials for use in the highly corrosive environments created by the decomposition products. Boron treated diamond film was a potential candidate for use in decomposer process equipment based on earlier studies concluding good oxidation resistance at elevated temperatures. However, little information was available relating the interactions of diamond and diamond films with sulfuric acid at temperatures greater than 350°C. A laboratory scale sulfuric acid decomposer simulator was constructed at the Nuclear Science and Engineering Institute at the University of Missouri-Columbia. The simulator was capable of producing the temperatures and corrosive environments that process equipment would be exposed to for industrialization of the sulfur iodide or hybrid sulfur thermochemical cycles. A series of boron treated synthetic diamonds were tested in the simulator to determine corrosion resistances and suitability for use in thermochemical process equipment. These studies were performed at twenty four hour durations at temperatures between 600°C to 926°C. Other materials, including natural diamond, synthetic diamond treated with titanium, silicon carbide, quartz, aluminum nitride, and Inconel

  11. Simple Thermal Decompose Method for Synthesis of Nickel Disulfide Nanostructures

    Science.gov (United States)

    Seyghalkar, Hamideh; Sabet, Mohammad; Salavati-Niasari, Masoud

    2016-11-01

    In this work, a simple thermal decompose method was served to synthesize NiS2 nanostructures via a nickel complex. Also polyethylene glycol (PEG) was used as surfactant to increase the steric effect around nanostructure surfaces and decrease the particles size. The product was characterized with different analysis methods. The crystal structure of the product was studied by X-ray diffraction (XRD) pattern. The particle size and morphology were investigated by scanning electron microscopy (SEM). To study the nanostructures surface purity, Fourier transform infrared spectroscopy (FT-IR) was used. And finally to study the optical properties of the product photoluminescence (PL) spectroscopy was served.

  12. Tensor-decomposed vibrational coupled-cluster theory

    DEFF Research Database (Denmark)

    Madsen, Niels Kristian; Godtliebsen, Ian Heide; Christiansen, Ove

    can be reduced by decomposing the VCC amplitudes and error vectors to the CANDECOMP/PARAFAC (CP) tensor format. Using the CP format allows us to automatically adapt the size of the parameter space as well as the computational effort to the strength of the physical interactions in the molecule while...... maintaining the same accuracy as the standard VCC method. We have implemented our VCC algorithms and equation solvers such that the VCC equations can be solved without constructing any tensors in full dimension. The tensors are automatically recompressed during the summation of the many terms in the VCC...

  13. Micro-photoluminescence of GaAs/AlGaAs triple concentric quantum rings.

    Science.gov (United States)

    Abbarchi, Marco; Cavigli, Lucia; Somaschini, Claudio; Bietti, Sergio; Gurioli, Massimo; Vinattieri, Anna; Sanguinetti, Stefano

    2011-10-31

    A systematic optical study, including micro, ensemble and time resolved photoluminescence of GaAs/AlGaAs triple concentric quantum rings, self-assembled via droplet epitaxy, is presented. Clear emission from localized states belonging to the ring structures is reported. The triple rings show a fast decay dynamics, around 40 ps, which is expected to be useful for ultrafast optical switching applications.

  14. The -250G>A promoter variant in hepatic lipase associates with elevated fasting serum high-density lipoprotein cholesterol modulated by interaction with physical activity in a study of 16,156 Danish subjects.

    Science.gov (United States)

    Grarup, Niels; Andreasen, Camilla H; Andersen, Mette K; Albrechtsen, Anders; Sandbaek, Annelli; Lauritzen, Torsten; Borch-Johnsen, Knut; Jørgensen, Torben; Schmitz, Ole; Hansen, Torben; Pedersen, Oluf

    2008-06-01

    Hepatic lipase plays a pivotal role in the metabolism of high-density lipoprotein (HDL) and low-density lipoprotein by involvement in reverse cholesterol transport and the formation of atherogenic small dense low-density lipoprotein. The objective was to investigate the impact of variants in LIPC on metabolic traits and type 2 diabetes in a large sample of Danes. Because behavioral factors influence hepatic lipase activity, we furthermore examined possible gene-environment interactions in the population-based Inter99 study. The LIPC -250G>A (rs2070895) variant was genotyped in the Inter99 study (n = 6070), the Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen Detected Diabetes in Primary Care Denmark screening cohort of individuals with risk factors for undiagnosed type 2 diabetes (n = 8662), and in additional type 2 diabetic patients (n = 1,064) and glucose-tolerant control subjects (n = 360). In the Inter99 study, the A allele of rs2070895 associated with a 0.057 mmol/liter [95% confidence interval (CI) 0.039-0.075] increase in fasting serum HDL-cholesterol (HDL-c) (P = 8 x 10(-10)) supported by association in the Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen Detected Diabetes in Primary Care study [0.038 mmol/liter per allele (95% CI 0.024-0.053); P = 2 x 10(-7)). The allelic effect on HDL-c was modulated by interaction with self-reported physical activity (P(interaction) = 0.002) because vigorous physically active homozygous A-allele carriers had a 0.30 mmol/liter (95% CI 0.22-0.37) increase in HDL-c compared with homozygous G-allele carriers. We validate the association of LIPC promoter variation with fasting serum HDL-c and present data supporting an interaction with physical activity implying an increased effect on HDL-c in vigorous physically active subjects carrying the -250 A allele. This interaction may have potential implications for public health and disease prevention.

  15. Relative distribution of drugs in decomposed skeletal tissue.

    Science.gov (United States)

    Watterson, James H; Desrosiers, Nathalie A; Betit, Caroline C; Dean, Dorothy; Wyman, John F

    2010-10-01

    Skeletal tissues from a domestic pig exposed to amitriptyline, diazepam, and pentobarbital were analyzed to determine the relative distribution of these drugs in bone. Following drug exposure and euthanasia, remains were allowed to decompose outdoors to complete skeletonization between summer 2007 and fall 2009. Remains were recovered and separated according to bone type. Twelve different bone types were pulverized and sampled in triplicate. Each bone sample underwent methanolic extraction (96 h, 50 °C), followed by solid-phase extraction and gas chromatography-mass spectrometry in the selected ion monitoring mode. Mass-normalized assay responses underwent ANOVA with post-hoc testing, revealing bone type as a main effect for all three drugs, but not for the diazepam metabolite (nordiazepam). The assay response varied with respect to bone type by factors of 27, 39, and 20 for pentobarbital, diazepam, and amitriptyline, respectively. The relative distribution between bone type was qualitatively similar for the three administered drugs analyzed for, with the largest response obtained from rib for all three drugs. This is the first study, to the authors' knowledge, of the distribution of different drugs in various decomposed skeletal tissues in a controlled experiment using an animal model of comparable physiology to humans. These data have implications for the interpretive value of forensic drug measurements in skeletal tissues.

  16. Optical Properties and Carrier Dynamics of GaAs/GaInAs Multiple-Quantum-Well Shell Grown on GaAs Nanowire by Molecular Beam Epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kwangwook; Ravindran, Sooraj; Ju, Gun Wu; Min, Jung-Wook; Kang, Seokjin; Myoung, NoSoung; Yim, Sang-Youp; Jo, Yong-Ryun; Kim, Bong-Joong; Lee, Yong Tak

    2016-12-01

    GaAs/GaInAs multiple-quantum-well (MQW) shells having different GaInAs shell width formed on the surface of self-catalyzed GaAs core nanowires (NWs) are grown on (100) Si substrate using molecular beam epitaxy. The photoluminescence emission from GaAs/GaInAs MQW shells and the carrier lifetime could be varied by changing the width of GaInAs shell. Time-resolved photoluminescence measurements showed that the carrier lifetime had a fast and slow decay owing to the mixing of wurtzite and zinc-blende structures of the NWs. Furthermore, strain relaxation caused the carrier lifetime to decrease beyond a certain thickness of GaInAs quantum well shells.

  17. Decomposing the Unsteady Flow Routing in River Systems

    Science.gov (United States)

    Gomez Cunya, L. A.; Leon, A.; Gibson, N. L.; Vasylkivska, V.

    2014-12-01

    This work presents an optimization-based domain decomposition strategy for unsteady flow routing in complex river systems. This strategy couples the domain decomposition technique with a Precomputed Channel Hydraulics Ensemble approach, known also as HydraulicPerformance Graph (HPG), which utilizes precomputed solutions along reaches on a river system. These solutions are stored in a database. While efficient and robust, HPGs requires extensive memory allocation, especially for high resolution simulations. Decomposing the river system into subdomains reduces computer memory constraints as each sub-domain is solved independently. Further, an optimization method is used to couple the sub-domains using the stored precomputed solution. In turn, the computational efficiency of the HPG approach allows the optimization-based scheme to be competitive with a whole domain methodology. The combined strategy is expected to reduce the overall computational time for large-scale problems. This work discusses the results of the application to the Columbia River (Northwest USA).

  18. Balanced vertex decomposable simplicial complexes and their h-vectors

    CERN Document Server

    Biermann, Jennifer

    2012-01-01

    Given any finite simplicial complex \\Delta, we show how to construct a new simplicial complex \\Delta_{\\chi} that is balanced and vertex decomposable. Moreover, we show that the h-vector of the simplicial complex \\Delta_{\\chi} is precisely the f-vector, denoted f(\\Delta), of the original complex \\Delta. We deduce this result by relating f(\\Delta) with the graded Betti numbers of the Alexander dual of \\Delta_{\\chi}. Our construction generalizes the "whiskering" construction of Villarreal, and Cook and Nagel. As a corollary of our work, we add a new equivalent statement to a theorem of Bj\\"orner, Frankl, and Stanley that classifies the f-vectors of simplicial complexes. We also prove a special case of a conjecture of Cook and Nagel, and Constantinescu and Varbaro on the h-vectors of flag complexes.

  19. New light on Bergman complexes by decomposing matroid types

    CERN Document Server

    Dlugosch, Martin

    2011-01-01

    Bergman complexes are polyhedral complexes associated to matroids. Faces of these complexes are certain matroids, called matroid types, too. In order to understand the structure of these faces we decompose matroid types into direct summands. Ardila/Klivans proved that the Bergman Complex of a matroid can be subdivided into the order complex of the proper part of its lattice of flats. Beyond that Feichtner/Sturmfels showed that the Bergman complex can even be subdivided to the even coarser nested set complex. We will give a much shorter and more general proof of this fact. Generalizing formulas proposed by Ardila/Klivans and Feichtner/Sturmfels for special cases, we present a decomposition into direct sums working for faces of any of these complexes. Additionally we show that it is the finest possible decomposition for faces of the Bergman complex.

  20. 'Willpower' over the life span: decomposing self-regulation.

    Science.gov (United States)

    Mischel, Walter; Ayduk, Ozlem; Berman, Marc G; Casey, B J; Gotlib, Ian H; Jonides, John; Kross, Ethan; Teslovich, Theresa; Wilson, Nicole L; Zayas, Vivian; Shoda, Yuichi

    2011-04-01

    In the 1960s, Mischel and colleagues developed a simple 'marshmallow test' to measure preschoolers' ability to delay gratification. In numerous follow-up studies over 40 years, this 'test' proved to have surprisingly significant predictive validity for consequential social, cognitive and mental health outcomes over the life course. In this article, we review key findings from the longitudinal work and from earlier delay-of-gratification experiments examining the cognitive appraisal and attention control strategies that underlie this ability. Further, we outline a set of hypotheses that emerge from the intersection of these findings with research on 'cognitive control' mechanisms and their neural bases. We discuss implications of these hypotheses for decomposing the phenomena of 'willpower' and the lifelong individual differences in self-regulatory ability that were identified in the earlier research and that are currently being pursued.

  1. Thermally decomposed ricebran oil as a diesel fuel

    Directory of Open Access Journals (Sweden)

    Megahed, O. A.

    1998-04-01

    Full Text Available Ricebran oil; a non edible oil, was thermally decomposed using different loads of calcium oxide as catalyst. The fuel properties of the cracked product were evaluated as compared to those of diesel fuel. The considered properties included the calorific value, flash point, viscosity, pour point, distillation characteristics, cetane number in addition to some other fuel properties. The results had shown that the fuel properties of the decomposed oil were quite similar to those of standard diesel fuel. The calorific value was 80-90% that of diesel fuel and the viscosity was sligthy higher. The prepared fuel was advantageous over diesel fuel as the former was completely free from sulfur, which on fuel combustion produces corrosive gases of sulfur oxides.

    Aceite de germen de arroz, un aceite no comestible, fue descompuesto térmicamente usando diferentes cantidades de óxido cálcico como catalizador. Las propiedades combustibles del producto craqueado fueron evaluadas comparándolas con las del gasóleo. Las propiedades consideradas incluyeron el poder calorífico, punto de inflamación, viscosidad, temperatura de fluidez crítica, características de destilación, número de cetano y otras propiedades de los combustibles. Los resultados han mostrado que las propiedades combustibles del aceite descompuesto fueron bastantes similares a la de los gasóleos estándar. El poder calorífico fue del 80-90% de la del gasóleo y la viscosidad ligeramente mayor. El combustible preparado fue ventajoso sobre el gasóleo ya que el primero estaba completamente libre de sulfuro, el cual produce en la combustión del carburante gases corrosivos de óxido de azufre.

  2. An optically pumped GaN/AlGaN quantum well intersubband terahertz laser

    Science.gov (United States)

    Fu, Ai-Bing; Hao, Ming-Rui; Yang, Yao; Shen, Wen-Zhong; Liu, Hui-Chun

    2013-02-01

    We propose an optically pumped nonpolar GaN/AlGaN quantum well (QW) active region design for terahertz (THz) lasing in the wavelength range of 30 μm ~ 40 μm and operating at room temperature. The fast longitudinal optical (LO) phonon scattering in GaN/AlGaN QWs is used to depopulate the lower laser state, and more importantly, the large LO phonon energy is utilized to reduce the thermal population of the lasing states at high temperatures. The influences of temperature and pump intensity on gain and electron densities are investigated. Based on our simulations, we predict that with a sufficiently high pump intensity, a room temperature operated THz laser using a nonpolar GaN/AlGaN structure is realizable.

  3. Decomposing ERP time-frequency energy using PCA.

    Science.gov (United States)

    Bernat, Edward M; Williams, William J; Gehring, William J

    2005-06-01

    Time-frequency transforms (TFTs) offer rich representations of event-related potential (ERP) activity, and thus add complexity. Data reduction techniques for TFTs have been slow to develop beyond time analysis of detail functions from wavelet transforms. Cohen's class of TFTs based on the reduced interference distribution (RID) offer some benefits over wavelet TFTs, but do not offer the simplicity of detail functions from wavelet decomposition. The objective of the current approach is a data reduction method to extract succinct and meaningful events from both RID and wavelet TFTs. A general energy-based principal components analysis (PCA) approach to reducing TFTs is detailed. TFT surfaces are first restructured into vectors, recasting the data as a two-dimensional matrix amenable to PCA. PCA decomposition is performed on the two-dimensional matrix, and surfaces are then reconstructed. The PCA decomposition method is conducted with RID and Morlet wavelet TFTs, as well as with PCA for time and frequency domains separately. Three simulated datasets were decomposed. These included Gabor logons and chirped signals. All simulated events were appropriately extracted from the TFTs using both wavelet and RID TFTs. Varying levels of noise were then added to the simulated data, as well as a simulated condition difference. The PCA-TFT method, particularly when used with RID TFTs, appropriately extracted the components and detected condition differences for signals where time or frequency domain analysis alone failed. Response-locked ERP data from a reaction time experiment was also decomposed. Meaningful components representing distinct neurophysiological activity were extracted from the ERP TFT data, including the error-related negativity (ERN). Effective TFT data reduction was achieved. Activity that overlapped in time, frequency, and topography were effectively separated and extracted. Methodological issues involved in the application of PCA to TFTs are detailed, and

  4. Reduced Toxicity Fuel Satellite Propulsion System Including Catalytic Decomposing Element with Hydrogen Peroxide

    Science.gov (United States)

    Schneider, Steven J. (Inventor)

    2002-01-01

    A reduced toxicity fuel satellite propulsion system including a reduced toxicity propellant supply for consumption in an axial class thruster and an ACS class thruster. The system includes suitable valves and conduits for supplying the reduced toxicity propellant to the ACS decomposing element of an ACS thruster. The ACS decomposing element is operative to decompose the reduced toxicity propellant into hot propulsive gases. In addition the system includes suitable valves and conduits for supplying the reduced toxicity propellant to an axial decomposing element of the axial thruster. The axial decomposing element is operative to decompose the reduced toxicity propellant into hot gases. The system further includes suitable valves and conduits for supplying a second propellant to a combustion chamber of the axial thruster, whereby the hot gases and the second propellant auto-ignite and begin the combustion process for producing thrust.

  5. Differentiation between decomposed remains of human origin and bigger mammals.

    Science.gov (United States)

    Rosier, E; Loix, S; Develter, W; Van de Voorde, W; Cuypers, E; Tytgat, J

    2017-08-01

    This study is a follow-up study in the search for a human specific marker in the decomposition where the VOC-profile of decomposing human, pig, lamb and roe remains were analyzed using a thermal desorber combined with a gas chromatograph coupled to a mass spectrometer in a laboratory environment during 6 months. The combination of 8 previously identified human and pig specific compounds (ethyl propionate, propyl propionate, propyl butyrate, ethyl pentanoate, 3-methylthio-1-propanol, methyl(methylthio)ethyl disulfide, diethyl disulfide and pyridine) was also seen in these analyzed mammals. However, combined with 5 additional compounds (hexane, heptane, octane, N-(3-methylbutyl)- and N-(2-methylpropyl)acetamide) human remains could be separated from pig, lamb and roe remains. Based on a higher number of remains analyzed, as compared with the pilot study, it was no longer possible to rely on the 5 previously proposed esters to separate pig from human remains. From this follow-up study reported, it was found that pyridine is an interesting compound specific to human remains. Such a human specific marker can help in the training of cadaver dogs or in the development of devices to search for human remains. However, further investigations have to verify these results. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  6. Decomposing the aerodynamic forces of low-Reynolds flapping airfoils

    Science.gov (United States)

    Moriche, Manuel; Garcia-Villalba, Manuel; Flores, Oscar

    2016-11-01

    We present direct numerical simulations of flow around flapping NACA0012 airfoils at relatively small Reynolds numbers, Re = 1000 . The simulations are carried out with TUCAN, an in-house code that solves the Navier-Stokes equations for an incompressible flow with an immersed boundary method to model the presence of the airfoil. The motion of the airfoil is composed of a vertical translation, heaving, and a rotation about the quarter of the chord, pitching. Both motions are prescribed by sinusoidal laws, with a reduced frequency of k = 1 . 41 , a pitching amplitude of 30deg and a heaving amplitude of one chord. Both, the mean pitch angle and the phase shift between pitching and heaving motions are varied, to build a database with 18 configurations. Four of these cases are analysed in detail using the force decomposition algorithm of Chang (1992) and Martín Alcántara et al. (2015). This method decomposes the total aerodynamic force into added-mass (translation and rotation of the airfoil), a volumetric contribution from the vorticity (circulatory effects) and a surface contribution proportional to viscosity. In particular we will focus on the second, analysing the contribution of the leading and trailing edge vortices that typically appear in these flows. This work has been supported by the Spanish MINECO under Grant TRA2013-41103-P. The authors thankfully acknowledge the computer resources provided by the Red Española de Supercomputacion.

  7. Transformation rules for decomposing heterogeneous data into triples

    Directory of Open Access Journals (Sweden)

    Mrityunjay Singh

    2015-04-01

    Full Text Available In order to fulfill the vision of a dataspace system, it requires a flexible, powerful and versatile data model that is able to represent a highly heterogeneous mix of data such as databases, web pages, XML, deep web, and files. In literature, the triple model was found a suitable candidate for a dataspace system, and able to represent structured, semi-structured and unstructured data into a single model. A triple model is based on the decomposition theory, and represents variety of data into a collection of triples. In this paper, we have proposed a decomposition algorithm for expressing various heterogeneous data models into the triple model. This algorithm is based on the decomposition theory of the triple model. By applying the decomposition algorithm, we have proposed a set of transformation rules for the existing data models. The transformation rules have been categorized for structured, semi-structured, and unstructured data models. These rules are able to decompose most of the existing data models into the triple model. We have empirically verified the algorithm as well as the transformation rules on different data sets having different data models.

  8. Toxic effects of decomposing red algae on littoral organisms

    Science.gov (United States)

    Eklund, Britta; Svensson, Andreas P.; Jonsson, Conny; Malm, Torleif

    2005-03-01

    Large masses of filamentous red algae of the genera Polysiphonia, Rhodomela, and Ceramium are regularly washed up on beaches of the central Baltic Sea. As the algal masses start to decay, red coloured effluents leak into the water, and this tinge may be traced several hundred meters off shore. In this study, possible toxic effects of these effluents were tested on littoral organisms from different trophic levels. Effects on fertilisation, germination and juvenile survival of the brown seaweed Fucus vesiculosus were investigated, and mortality tests were performed on the crustaceans Artemia salina and Idotea baltica, as well as on larvae and adults of the fish Pomatoschistus microps. Fucus vesiculosus was the most sensitive species of the tested organisms to the red algal extract. The survival of F. vesiculosus recruits was reduced with 50% (LC50) when exposed to a concentration corresponding to 1.7 g l -1 dw red algae. The lethal concentration for I. baltica, A. salina and P. microps were approximately ten times higher. The toxicity to A. salina was reduced if the algal extract was left to decompose during two weeks but the decline in toxicity was not affected by different light or temperature conditions. This study indicates that the filamentous red algae in the central Baltic Sea may produce and release compounds with negative effects on the littoral ecosystem. The effects may be particularly serious for the key species F. vesiculosus, which reproduce in autumn when filamentous red algal blooms are most severe.

  9. Decomposability of Abstract and Path-Induced Convexities in Hypergraphs

    Directory of Open Access Journals (Sweden)

    Malvestuto Francesco Mario

    2015-08-01

    Full Text Available An abstract convexity space on a connected hypergraph H with vertex set V (H is a family C of subsets of V (H (to be called the convex sets of H such that: (i C contains the empty set and V (H, (ii C is closed under intersection, and (iii every set in C is connected in H. A convex set X of H is a minimal vertex convex separator of H if there exist two vertices of H that are separated by X and are not separated by any convex set that is a proper subset of X. A nonempty subset X of V (H is a cluster of H if in H every two vertices in X are not separated by any convex set. The cluster hypergraph of H is the hypergraph with vertex set V (H whose edges are the maximal clusters of H. A convexity space on H is called decomposable if it satisfies the following three properties:

  10. Decomposed characteristic of azo dyes by ozonization with ultrasonic enhancement

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Azo dyes have been used in many industries (textile mill, printing and dyeing mill, paper and pulp mill) and have caused great environmental pollution due to complicated constitution and high chemical stability. The construction of azo dyes can be destroyed by ozonization, but not thoroughly when the ozone dosage is controlled to a certain extent and the operating cost is higher. Ozonization decomposed ability with ultrasonic enhancement on azo dyes has been demonstrated in the study. The conclusion derived from this investigation may be summarized as follows: (1) The decoloration rate of arsenazoⅠsolutions during sonozone treatment is more rapid than the rate obtained with ozone alone because the complicated constitution has been destroyed by the O free radical from ozone decomposition. (2) The destructing pathway of arsenazoⅠby ozone with ultrasound is identical with that of by ozone alone: the breakdown of -N== N- bonds, the conversion of benzene ring to carboxylic acid, and -HSO3 bonds to H2SO4. So, pH value of the arsenazo Ⅰ solution continuously drops down to 3.2.

  11. Decomposing the effect of crime on population changes.

    Science.gov (United States)

    Foote, Andrew

    2015-04-01

    This article estimates the effect of crime on migration rates for counties in U.S. metropolitan areas and makes three contributions to the literature. First, I use administrative data on migration flows between counties, which gives me more precise estimates of population changes than data used in previous studies. Second, I am able to decompose net population changes into gross migration flows in order to identify how individuals respond to crime rate changes. Finally, I include county-level trends so that my identification comes from shocks away from the trend. I find effects that are one-fiftieth the size of the most prominent estimate in the literature; and although the long-run effects are somewhat larger, they are still only approximately one-twentieth as large. I also find that responses to crime rates differ by subgroups, and that increases in crime cause white households to leave the county, with effects almost 10 times as large as for black households.

  12. Communities of fungi in decomposed wood of oak and pine

    Directory of Open Access Journals (Sweden)

    Kwaśna Hanna

    2016-09-01

    Full Text Available The abundance and diversity of wood decomposing fungi were investigated by isolating and cultivating filamentous fungi from wood and by detection of fruit bodies of ascomycetous and basidiomycetous fungi. The objective was to study the impact of forest management on fungi in 100-year-old oak and 87-year-old Scots pine forests in Northern Poland. Fungi were found on coarse woody debris of decayed stumps and fallen logs, boughs and branches in each of the three (managed and unmanaged examined stands. In total, 226 species of Oomycota and fungi were recorded. Oak wood was colonized by one species of Oomycota and 141 species of fungi including Zygomycota (19 species, Ascomycota (103 species and Basidiomycota (19 species. Scots pine wood was also colonized by one species of Oomycota and 138 species of fungi including Zygomycota (19 species, Ascomycota (90 species and Basidiomycota (29 species. In the first, second and third stages of decomposition, the oak wood was colonized by 101, 89 and 56 species of fungi respectively and pine wood was colonized by 82, 103 and 47 species respectively. Eighty three of the observed species (37% occurred on both types of wood, while the other species displayed nutritional preferences. A decrease in the number of species with advancing decay indicates the necessity for a continuous supply of dead wood to the forest ecosystem.

  13. Patterned growth of InGaN/GaN quantum wells on freestanding GaN grating by molecular beam epitaxy

    Directory of Open Access Journals (Sweden)

    Wang Yongjin

    2011-01-01

    Full Text Available Abstract We report here the epitaxial growth of InGaN/GaN quantum wells on freestanding GaN gratings by molecular beam epitaxy (MBE. Various GaN gratings are defined by electron beam lithography and realized on GaN-on-silicon substrate by fast atom beam etching. Silicon substrate beneath GaN grating region is removed from the backside to form freestanding GaN gratings, and the patterned growth is subsequently performed on the prepared GaN template by MBE. The selective growth takes place with the assistance of nanoscale GaN gratings and depends on the grating period P and the grating width W. Importantly, coalescences between two side facets are realized to generate epitaxial gratings with triangular section. Thin epitaxial gratings produce the promising photoluminescence performance. This work provides a feasible way for further GaN-based integrated optics devices by a combination of GaN micromachining and epitaxial growth on a GaN-on-silicon substrate. PACS 81.05.Ea; 81.65.Cf; 81.15.Hi.

  14. Linkages between below and aboveground communities: Decomposer responses to simulated tree species loss are largely additive.

    Science.gov (United States)

    Becky A. Ball; Mark A. Bradford; Dave C. Coleman; Mark D. Hunter

    2009-01-01

    Inputs of aboveground plant litter influence the abundance and activities of belowground decomposer biota. Litter-mixing studies have examined whether the diversity and heterogeneity of litter inputs...

  15. Natural manganese deposits as catalyst for decomposing hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    A. H. Knol

    2015-01-01

    Full Text Available Drinking water companies more and more implement Advanced Oxidation Processes (AOP in their treatment schemes to increase the barrier against organic micropollutants (OMPs. It is necessary to decompose the excessive hydrogen peroxide after applying AOP to avoid negative effects in the following, often biological, treatment steps. A drinking water company in the western part of the Netherlands investigated decomposition of about 5.75 mg L−1 hydrogen peroxide in pre-treated Meuse river water with different catalysts on pilot scale. In down flow operation, the necessary reactor Empty Bed Contact Time (EBCT with the commonly used Granulated Activated Carbon (GAC and waste ground water filter gravel (MCFgw were the same with 149 s, corresponding with a conversion rate constant r of 0.021 s−1. The EBCT of the fine coating of ground water filter gravel (MC was significantly shorter with a little more than 10 s (r = 0.30 s−1. In up flow operation, with a flow rate of 20 m h−1, the EBCT of coating MC increased till about 100 s (r = 0.031 s−1, from which can be concluded, that the performance of this waste material is better compared with GAC, in both up and down flow operation. The necessary EBCT at average filtration rate of full scale dual layer filter material (MCFsw amounted to 209 s (r = 0.015 s−1. Regarding the average residence time in the full scale filters of 700 s, applying AOP in front of the filters could be an interesting alternative which makes a separate decomposition installation superfluous, on the condition that the primary functions of the filters are not affected.

  16. Nematophagous fungi from decomposing cattle faeces in Argentina.

    Science.gov (United States)

    Saumell, Carlos Alfredo; Fernández, Alicia Silvina; Fusé, Luis Alberto; Rodríguez, Manuela; Sagüés, María Federica; Iglesias, Lucía Emilia

    2015-01-01

    Biological control of gastrointestinal nematodes of ruminants by use of nematophagous fungi would become part of any livestock parasite integral control system. Identifying autochthonous species that could then be selected for mass production is an important phase in the practical use of biological control. To search for nematophagous fungi with potential use as biological control agents against gastrointestinal nematodes in Argentina. Decomposing cattle faeces sampled in different locations were incubated in water agar 2% with Panagrellus sp. The developed nematophagous fungi were transferred to new water agar 2% plates and then to corn meal agar plates in order to carry out their identification. Fungal diversity and richness were also assessed. Seventeen species from nine genera of nematophagous fungi were found. Twelve species were nematode-trapping fungi and three species plus two fungi identified to genus level corresponded to endoparasitic fungi. Arthrobotrys conoides, Arthrobotrys oligospora, Duddingtonia flagrans, Monacrosporium doedycoides, Arthrobotrys robusta and Drechmeria coniospora were the most frequently isolated species overall in the whole study (6.6%, 5.7%, 5.7%, 5.7%, 4.7% and 4.7%, respectively) although other species were more frequently recorded at local levels such as Arthrobotrys pyriformis (18.8%). Only A. conoides has been previously isolated from ruminant faecal samples in Argentina. Five nematode-trapping fungal species are mentioned for the first time in the Americas D. flagrans and A. conoides, both identified in the present study, are among the most promising ones as biological control agents against gastrointestinal nematodes of ruminants. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  17. Biogeochemical implications of decomposing jellyfish blooms in a changing climate

    Science.gov (United States)

    Chelsky, Ariella; Pitt, Kylie A.; Welsh, David T.

    2015-03-01

    Jellyfish often exhibit 'boom and bust' population dynamics whereby they proliferate rapidly and then die en masse and decompose. The few studies that have investigated post-bloom processes have not studied how changing ocean conditions will alter rates of decomposition. Climate change will result in warmer and more acidic waters, and studies therefore need to consider these factors in concert to determine their combined effect on decomposition processes. To quantify the effect, we measured oxygen consumption and nutrient regeneration rates during decomposition of Catostylus mosaicus in mesocosms at current average summer pH and temperature (pH 8.0 and 27 °C) as well as conditions projected for year 2100 (pH 7.8 and 30 °C) and compared these fluxes to control mesocosms without jellyfish over 12 days. We hypothesised that rates of jellyfish decomposition, as measured by oxygen demand and nutrient regeneration, would be accelerated in the end-of-century treatments, compared to present day treatments. Overall decomposition rates were only slightly elevated under end-of-century conditions, and the difference was only significant for ammonium fluxes from 19 h until 43 h after the experiment commenced. The difference between treatments was much smaller than would be expected due to the temperature increase, based on theoretical modelling of jellyfish decomposition which predicts a Q10 of 4.28, or a 1.5 fold increase in decomposition rates. This highlights the importance of investigating net effects on decomposition rates, as simultaneous shifts in temperature and pH may not follow patterns predicted due to one stressor alone. Ultimately, these results suggest that rates of oxygen consumption and nutrient regeneration resulting from collapsed jellyfish blooms may not change drastically over the next 100 years.

  18. Double-Resonance Facilitated Decomposion of Emission Spectra

    Science.gov (United States)

    Kato, Ryota; Ishikawa, Haruki

    2016-06-01

    Emission spectra provide us with rich information about the excited-state processes such as proton-transfer, charge-transfer and so on. In the cases that more than one excited states are involved, emission spectra from different excited states sometimes overlap and a decomposition of the overlapped spectra is desired. One of the methods to perform a decomposition is a time-resolved fluorescence technique. It uses a difference in time evolutions of components involved. However, in the gas-phase, a concentration of the sample is frequently too small to carry out this method. On the other hand, double-resonance technique is a very powerful tool to discriminate or identify a common species in the spectra in the gas-phase. Thus, in the present study, we applied the double-resonance technique to resolve the overlapped emission spectra. When transient IR absorption spectra of the excited state are available, we can label the population of the certain species by the IR excitation with a proper selection of the IR wavenumbers. Thus, we can obtain the emission spectra of labeled species by subtracting the emission spectra with IR labeling from that without IR. In the present study, we chose the charge-transfer emission spectra of cyanophenyldisilane (CPDS) as a test system. One of us reported that two charge-transfer (CT) states are involved in the intramolecular charge-transfer (ICT) process of CPDS-water cluster and recorded the transient IR spectra. As expected, we have succeeded in resolving the CT emission spectra of CPDS-water cluster by the double resonance facilitated decomposion technique. In the present paper, we will report the details of the experimental scheme and the results of the decomposition of the emission spectra. H. Ishikawa, et al., Chem. Phys. Phys. Chem., 9, 117 (2007).

  19. Linearity of photoconductive GaAs detectors to pulsed electrons

    Energy Technology Data Exchange (ETDEWEB)

    Ziegler, L.H.

    1995-12-31

    The response of neutron damaged GaAs photoconductor detectors to intense, fast (50 psec fwhm) pulses of 16 MeV electrons has been measured. Detectors made from neutron damaged GaAs are known to have reduced gain, but significantly improved bandwidth. An empirical relationship between the observed signal and the incident electron fluence has been determined.

  20. Experimental evidence that the Ornstein-Uhlenbeck model best describes the evolution of leaf litter decomposability.

    Science.gov (United States)

    Pan, Xu; Cornelissen, Johannes H C; Zhao, Wei-Wei; Liu, Guo-Fang; Hu, Yu-Kun; Prinzing, Andreas; Dong, Ming; Cornwell, William K

    2014-09-01

    Leaf litter decomposability is an important effect trait for ecosystem functioning. However, it is unknown how this effect trait evolved through plant history as a leaf 'afterlife' integrator of the evolution of multiple underlying traits upon which adaptive selection must have acted. Did decomposability evolve in a Brownian fashion without any constraints? Was evolution rapid at first and then slowed? Or was there an underlying mean-reverting process that makes the evolution of extreme trait values unlikely? Here, we test the hypothesis that the evolution of decomposability has undergone certain mean-reverting forces due to strong constraints and trade-offs in the leaf traits that have afterlife effects on litter quality to decomposers. In order to test this, we examined the leaf litter decomposability and seven key leaf traits of 48 tree species in the temperate area of China and fitted them to three evolutionary models: Brownian motion model (BM), Early burst model (EB), and Ornstein-Uhlenbeck model (OU). The OU model, which does not allow unlimited trait divergence through time, was the best fit model for leaf litter decomposability and all seven leaf traits. These results support the hypothesis that neither decomposability nor the underlying traits has been able to diverge toward progressively extreme values through evolutionary time. These results have reinforced our understanding of the relationships between leaf litter decomposability and leaf traits in an evolutionary perspective and may be a helpful step toward reconstructing deep-time carbon cycling based on taxonomic composition with more confidence.

  1. Screening of cellulose decomposing fungi in sandy dune soil of Horqin Sandy Land

    Institute of Scientific and Technical Information of China (English)

    ShaoKun Wang; XueYong Zhao; XiaoAn Zuo; XinPing Liu; Hao Qu; Wei Mao; JianYing Yun

    2015-01-01

    Cellulose decomposing fungi play an important role in litter decomposition and are decisive in nutrient cycling in sandy land ecosystems. Thirty-one strains were isolated to select efficient cellulose decomposers, and four efficient cellulose decomposing fungi (NM3-1, NM3-2, NM3-3, and NM3-4) were screened using a CMC (carboxymethyl cellulose) carbon source in dune soil of Horqin Sandy Land. They were identified as Asperigillus calidoustus, Fusarium oxysporum, Fusarium solani, and Hypocrea lixii by rDNA-ITS molecular biological methods. Cloth decomposition rates were 15.71%, 15.89%, 17.29%, and 17.89%by the four efficient decomposers incubated for 30 days, respectively. Screening of efficient cellulose decomposers can not only increase the dune soil functional microbe bank, but can also accelerate litter decom-position and available nutrient input in the Horqin Sandy Land.

  2. Crystal Structure of Garnet-Related Li-Ion Conductor Li7-3x Ga x La3Zr2O12: Fast Li-Ion Conduction Caused by a Different Cubic Modification?

    Science.gov (United States)

    Wagner, Reinhard; Redhammer, Günther J; Rettenwander, Daniel; Senyshyn, Anatoliy; Schmidt, Walter; Wilkening, Martin; Amthauer, Georg

    2016-03-22

    Li-oxide garnets such as Li7La3Zr2O12 (LLZO) are among the most promising candidates for solid-state electrolytes to be used in next-generation Li-ion batteries. The garnet-structured cubic modification of LLZO, showing space group Ia-3d, has to be stabilized with supervalent cations. LLZO stabilized with Ga(3+) shows superior properties compared to LLZO stabilized with similar cations; however, the reason for this behavior is still unknown. In this study, a comprehensive structural characterization of Ga-stabilized LLZO is performed by means of single-crystal X-ray diffraction. Coarse-grained samples with crystal sizes of several hundred micrometers are obtained by solid-state reaction. Single-crystal X-ray diffraction results show that Li7-3x Ga x La3Zr2O12 with x > 0.07 crystallizes in the acentric cubic space group I-43d. This is the first definite record of this cubic modification for LLZO materials and might explain the superior electrochemical performance of Ga-stabilized LLZO compared to its Al-stabilized counterpart. The phase transition seems to be caused by the site preference of Ga(3+). (7)Li NMR spectroscopy indicates an additional Li-ion diffusion process for LLZO with space group I-43d compared to space group Ia-3d. Despite all efforts undertaken to reveal structure-property relationships for this class of materials, this study highlights the potential for new discoveries.

  3. Photocatalytic Hydrogen and Oxygen Formation from Water over Ga-modified Zeolite

    Institute of Scientific and Technical Information of China (English)

    Chong Heng HE; O Bong YANG

    2004-01-01

    Water could be decomposed into hydrogen and oxygen over Ga-modified ZSM-5 zeolite under UV irradiation. The photocatalytic activity was elevated significantly by supporting the gallium species and was sensitive to the loading amount of gallium species on the ZSM-5 zeolites.

  4. Growth initiation processes for GaAs and AlGaAs in CBE

    CERN Document Server

    Hill, D

    2002-01-01

    'in-growth' reconstruction to stabilise. However unlike for TMGa, GaAs growth with TEGa proceeds by a non-self limiting growth mode and TEGa rapidly dissociates. The result of this is that TEGa decomposes on top of other TEGa molecules, or their fragments and due to the high flux rate this leads to a 'stacking-up' of Ga on the surface. The presence of excess Ga provides a rapid increase of surface reflectance and then its subsequent decay as the excess Ga is incorporated by the increasing As content of the surface. The average growth rate during the transient period is equal to that of subsequent 'post-transient' period. However it is not certain as to whether the growth rate is constant throughout the transient period. The aim of this work was to investigate the nature of the transient period found in reflectance anisotropy (RA) measurements of high III:V BEP ratio growth of gallium arsenide (GaAs) and aluminium gallium arsenide (AIGaAs) by chemical beam epitaxy (CBE). Growth at substrate temperatures betwee...

  5. Applying Decomposed Theory of Planned Behaviour towards a Comprehensive Understanding of Social Network Usage in Saudi Arabia

    National Research Council Canada - National Science Library

    Waleed A. Al-Ghaith

    2016-01-01

    .... For this purpose, the Decomposed Theory of Planned Behaviour is utilized. Data collected from a survey of 1100 participants and distilled to 657 usable sets has been analysed to assess the predictive power of Decomposed Theory of Planned Behaviour...

  6. Limited transfer of nitrogen between wood decomposing and ectomycorrhizal mycelia when studied in the field

    DEFF Research Database (Denmark)

    Wallander, Håkan; Lindahl, Björn D.; Nilsson, Lars Ola

    2006-01-01

    Transfer of 15N between interacting mycelia of a wood-decomposing fungus (Hypholoma fasciculare) and an ectomycorrhizal fungus (Tomentellopsis submollis) was studied in a mature beech (Fagus sylvatica) forest. The amount of 15N transferred from the wood decomposer to the ectomycorrhizal fungus...... was compared to the amount of 15N released from the wood-decomposing mycelia into the soil solution as 15N-NH4. The study was performed in peat-filled plastic containers placed in forest soil in the field. The wood-decomposing mycelium was growing from an inoculated wood piece and the ectomycorrhizal mycelium...... from an introduced root from a mature tree. The containers were harvested after 41 weeks when physical contact between the two foraging mycelia was established. At harvest, 15N content was analyzed in the peat (total N and 15NH4+) and in the mycorrhizal roots. A limited amount of 15N was transferred...

  7. Suppression of soil decomposers and promotion of long-lived, root herbivorous nematodes by climate change

    DEFF Research Database (Denmark)

    Stevnbak, Karen; Maraldo, Kristine; Georgieva, Slavka

    2012-01-01

    to climate change predictions for the coming decades. Removing precipitation for two summer months reduced all decomposer organisms assessed, i.e., microbial biomass, protozoa, bacteri- and fungivorous nematodes and enchytraeids, probably with negative effects on soil decomposition. Increasing temperature...

  8. Conversion efficiency in the shrimp, Metapenaeus monoceros (Fabricius), fed on decomposed mangrove leaves

    Digital Repository Service at National Institute of Oceanography (India)

    Sumitra-Vijayaraghavan; Ramadhas, V.

    Feeding experiments were carried out with Metapenaeus monoceros using mangrove leaves at different stages of decomposition, in combination with rice bran. Maximum conversion efficiency was found in shrimps fed completely decomposed mangrove leaves...

  9. Decomposing a planar graph into an independent set and a 3-degenerate graph

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2001-01-01

    We prove the conjecture made by O. V. Borodin in 1976 that the vertex set of every planar graph can be decomposed into an independent set and a set inducing a 3-degenerate graph. (C) 2001 Academic Press.......We prove the conjecture made by O. V. Borodin in 1976 that the vertex set of every planar graph can be decomposed into an independent set and a set inducing a 3-degenerate graph. (C) 2001 Academic Press....

  10. Crystal Structure of Garnet-Related Li-Ion Conductor Li7–3x Ga x La3Zr2O12: Fast Li-Ion Conduction Caused by a Different Cubic Modification?

    OpenAIRE

    Wagner, Reinhard; Redhammer, Günther J.; Rettenwander, Daniel; Senyshyn, Anatoliy; Schmidt, Walter; Wilkening, Martin; Amthauer, Georg

    2016-01-01

    Li-oxide garnets such as Li7La3Zr2O12 (LLZO) are among the most promising candidates for solid-state electrolytes to be used in next-generation Li-ion batteries. The garnet-structured cubic modification of LLZO, showing space group Ia-3d, has to be stabilized with supervalent cations. LLZO stabilized with Ga3+ shows superior properties compared to LLZO stabilized with similar cations; however, the reason for this behavior is still unknown. In this study, a comprehensive structural characteriz...

  11. Hydrogenation induced structure and property changes in GdGa

    Energy Technology Data Exchange (ETDEWEB)

    Nedumkandathil, Reji; Kranak, Verina F. [Department of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm (Sweden); Johansson, Robert [Department Physics and Astronomy, Uppsala University, Box 516, SE-75210 Uppsala (Sweden); Ångström, Jonas [Department of Chemistry - Ångström Laboratory, Uppsala University, Box 538, SE-75121 Uppsala (Sweden); Balmes, Oliver [MAX IV Laboratory, Lund University, Box 118, SE-22100 Lund (Sweden); Andersson, Mikael S.; Nordblad, Per [Department of Engineering Sciences, Uppsala University, Box 534, SE-75121 Uppsala (Sweden); Scheicher, Ralph H. [Department Physics and Astronomy, Uppsala University, Box 516, SE-75210 Uppsala (Sweden); Sahlberg, Martin [Department of Chemistry - Ångström Laboratory, Uppsala University, Box 538, SE-75121 Uppsala (Sweden); Häussermann, Ulrich [Department of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm (Sweden)

    2016-07-15

    Hydrides GdGaH{sub x} were obtained by exposing the Zintl phase GdGa with the CrB structure to a hydrogen atmosphere at pressures from 1.5 to 50 bar and temperatures from 50 to 500 °C. Structural analysis by powder X-ray diffraction suggests that conditions with hydrogen pressures in a range between 15 and 50 bar and temperatures below 500 °C afford a uniform hydride phase with the NdGaH{sub 1.66} structure (Cmcm, a=3.9867(7) Å, b=12.024(2) Å, c=4.1009(6) Å) which hosts H in two distinct positions, H1 and H2. H1 is coordinated in a tetrahedral fashion by Gd atoms, whereas H2 atoms are inserted between Ga atoms. The assignment of the NdGaH{sub 1.66} structure is corroborated by first principles DFT calculations. Modeling of phase and structure stability as a function of composition resulted in excellent agreement with experimental lattice parameters when x=1.66 and revealed the presence of five-atom moieties Ga-H2-Ga-H2-Ga in GdGaH{sub 1.66}. From in situ powder X-ray diffraction using synchrotron radiation it was established that hydrogenation at temperatures above 200 °C affords a hydride with x≈1.3, which is stable up to 500 °C, and that additional H absorption, yielding GdGaH{sub 1.66}, takes place at lower temperatures. Consequently, GdGaH{sub 1.66} desorbs H above T=200 °C. Without the presence of hydrogen, hydrides GdGaH{sub x} decompose at temperatures above 300 °C into GdH{sub 2} and an unidentified Gd-Ga intermetallics. Thus the hydrogenation of GdGa is not reversible. From magnetic measurements the Curie-Weiss constant and effective magnetic moment of GdGaH{sub 1.66} were obtained. The former indicates antiferromagnetic interactions, the latter attains a value of ~8 μ{sub B} which is typical for compounds containing Gd{sup 3+}ions. - Graphical abstract: Ferromagnetic GdGa absorbs hydrogen in two steps to yield antiferromagnetic GdGaH{sub 1.66}. Display Omitted - Highlights: • Elucidation of hydrogen uptake behavior of the rare earth gallide

  12. GaSe oxidation in air: from bulk to monolayers

    Science.gov (United States)

    Rahaman, Mahfujur; Rodriguez, Raul D.; Monecke, Manuel; Lopez-Rivera, Santos A.; Zahn, Dietrich R. T.

    2017-10-01

    Two-dimensional (2D) van derWaals semiconductors have been the subject of intense research due to their low dimensionality and tunable optoelectronic properties. However, the stability of these materials in air is one of the important issues that needs to be clarified, especially for technological applications. Here the time evolution of GaSe oxidation from monolayer to bulk is investigated by Raman spectroscopy, photoluminescence emission, and x-ray photoelectron spectroscopy. The Raman spectroscopy study reveals that GaSe monolayers become oxidized almost immediately after exposure to air. However, the oxidation is a self-limiting process taking roughly 5 h to penetrate up to 3 layers of GaSe. After oxidation, GaSe single-layers decompose into amorphous Se which has a strong Raman cross section under red excitation. The present study provides a clear picture of the stability of GaSe in air and will guide future research of GaSe from single- to few-layers for the appropriate development of novel technological applications for this promising 2D material.

  13. AlGaN/GaN based field effect transistors for terahertz detection and imaging

    Science.gov (United States)

    Sakowicz, M.; Lifshits, M. B.; Klimenko, O. A.; Coquillat, D.; Dyakonova, N.; Teppe, F.; Gaquière, C.; Poisson, M. A.; Delage, S.; Knap, W.

    2012-03-01

    AlGaN/GaN based FETs have great potential as sensitive and fast operating detectors because of their material advantages such as high breakdown voltage, high electron mobility, and high saturation velocity. These advantages could be exploited for resonant and non-resonant terahertz detection. We have designed, fabricated, and characterized AlGaN/GaN based FETs as single pixel terahertz detectors. This work focuses on non-resonant detection and imaging using GaN field plate FETs. To evaluate their performances as terahertz detectors, we have measured the responsivity as a function of gate voltage, the azimuthal angle between the terahertz electric field, the source-to-drain direction, and the temperature. A simple analytical model of the response is developed. It is based on plasma density perturbation in the transistor channel by the incoming terahertz radiation. The model shows how the non-resonant detection signal is related to static (dc) transistor characteristics and it fully describes the experimental results on the non-resonant sub-terahertz detection by the AlGaN/GaN based FETs. The imaging performances are evaluated by scanning objects in transmission mode and an example of application of terahertz imaging as new non-destructive technique for the quality control of materials is given. Results indicate that these FETs can be considered as promising devices for terahertz detection and imaging applications.

  14. Carbon and nitrogen status of decomposing roots in three adjacent coniferous plantations

    Directory of Open Access Journals (Sweden)

    Jaeyeob Jeong

    2014-07-01

    Full Text Available This study evaluated the carbon (C and nitrogen (N status of decomposing roots in three adjacent plantations consisting of one deciduous (larch: Larix leptolepis and two evergreen (red pine: Pinus densiflora; rigitaeda pine: P. rigitaeda species planted in the same year (1963 under similar site conditions. The mass loss rates and C and N status of three diameter classes of roots (UF < 2 mm, F 2-5 mm, CF 5-10 mm in diameter were examined in the upper 15 cm of the mineral soil using in situ buried root bags for 496 days.The remaining mass of decomposing roots was significantly higher for larch (69.0% than for red pine (59.6% or rigitaeda pine (59.1% over 496 days. The mass loss rates of decomposing roots did not differ significantly among the three root diameter classes, but the C and N status of decomposing roots was affected by the tree species. The larch roots showed low C concentrations but high N concentrations, C and N remaining compared to the pine roots over the study period. The results indicate that the substrate quality indicators of roots were not attributed to the mass loss rates, C and N status of decomposing roots in three coniferous tree species grown under similar environmental conditions.

  15. Carbon and nitrogen status of decomposing roots in three adjacent coniferous plantations

    Directory of Open Access Journals (Sweden)

    Jaeyeob Jeong

    2014-07-01

    Full Text Available This study evaluated the carbon (C and nitrogen (N status of decomposing roots in three adjacent plantations consisting of one deciduous (larch: Larix leptolepis and two evergreen (red pine: Pinus densiflora; rigitaeda pine: P. rigitaeda species planted in the same year (1963 under similar site conditions. The mass loss rates and C and N status of three diameter classes of roots (UF < 2 mm, F 2-5 mm, CF 5-10 mm in diameter were examined in the upper 15 cm of the mineral soil using in situ buried root bags for 496 days.The remaining mass of decomposing roots was significantly higher for larch (69.0% than for red pine (59.6% or rigitaeda pine (59.1% over 496 days. The mass loss rates of decomposing roots did not differ significantly among the three root diameter classes, but the C and N status of decomposing roots was affected by the tree species. The larch roots showed low C concentrations but high N concentrations, C and N remaining compared to the pine roots over the study period. The results indicate that the substrate quality indicators of roots were not attributed to the mass loss rates, C and N status of decomposing roots in three coniferous tree species grown under similar environmental conditions.

  16. Solid Phase Reactions of Ni-GaAs Alloys for High Mobility Ⅲ-Ⅴ MOSFET Applications

    Institute of Scientific and Technical Information of China (English)

    LU Li; CHANG Hu-Dong; SUN Bing; WANG Hong; XUE Bai-Qing; ZHAO We; LIU Hong-Gang

    2012-01-01

    The solid phase reactions of Ni with GaAs substrates are investigated.The experimental results reveal that the Ni-GaAs solid phase reaction forms a ternary phase of Ni2GaAs when annealing temperatures are in the range 250 300℃.As the annealing temperature increases to 400℃,the Ni2GaAs phase starts to decompose due to NiAs phase precipitation.Ni-GaAs alloys processed at 400℃ with a 3min annealing time demonstrate a sheet resistance of 30Ω/square after unreacted Ni removal in hot diluted-HCl solutions.Therefore,Ni-GaAs alloys formed by solid phase reaction could be promising metallic source/drain structures with significant low series resistance for high mobility Ⅲ-Ⅴ metal-oxide-semiconductor field effect transistor (MOSFET) applications.%The solid phase reactions of Ni with GaAs substrates are investigated. The experimental results reveal that the Ni-GaAs solid phase reaction forms a ternary phase of Ni2GaAs when annealing temperatures are in the range 250-300℃. As the annealing temperature increases to 400℃, the Ni2GaAs phase starts to decompose due to NiAs phase precipitation. Ni-GaAs alloys processed at 400℃ with a 3 min annealing time demonstrate a sheet resistance of 30Ω/square after unreacted Ni removal in hot diluted-HCl solutions. Therefore, Ni-GaAs alloys formed by solid phase reaction could be promising metallic source/drain structures with significant low series resistance for high mobility III-V metal-oxide-semiconductor field effect transistor (MOSFET) applications.

  17. EQUIVALENCE OF REFINED THEORY AND DECOMPOSED THEOREM OF AN ELASTIC PLATE

    Institute of Scientific and Technical Information of China (English)

    ZHAO Bao-sheng; WANG Min-zhong

    2005-01-01

    A connection between Cheng's refined theory and Gregory's decomposed theorem is analyzed. The equivalence of the refined theory and the decomposed theorem is given. Using operator matrix determinant of partial differential equation, Cheng gained one equation, and he substituted the sum of the general integrals of three differential equations for the solution of the equation. But he did not prove the rationality of substitute. There, a whole proof for the refined theory from Papkovich-Neuber solution was given. At first expressions were obtained for all the displacements and stress components in term of the midplane displacement and its derivatives. Using Lur'e method and the theorem of appendix,the refined theory was given. At last, using basic mathematic method, the equivalence between Cheng's refined theory and Gregory's decomposed theorem was proved, i.e.,Cheng' s bi-harmonic equation, shear equation and transcendental equation are equivalent to Gregory's interior state, shear state and Papkovich-Fadle state, respectively.

  18. Short-term responses of decomposers and vegetation to stump removal

    Energy Technology Data Exchange (ETDEWEB)

    Kataja-aho, S.

    2011-07-01

    Stump removal has become a common practice to produce raw material for bioenergy production. It was hypothesized that stump removal is an extensive and more intense disturbance for forest ecosystems (soil decomposer organisms and vegetation) compared to traditional site preparation after clear cutting. Therefore, the effects of stump harvesting on forest soil decomposers, vegetation and nutrient dynamics in undisturbed patches of the forest soil and in exposed mineral soil were compared to the effects of the traditional site preparation method, mounding. Nematodes and enchytraeids were the only decomposer groups that were directly affected (negatively) by the stump removal. Regardless of the treatment, the abundances of most of the decomposer groups were consistently lower in the exposed mineral soil than in the intact forest soil. There was 2-3 times more exposed mineral soil in stump removal sites compared to mounding sites. When this was taken into account, the decomposer community was negatively affected by the stump removal at the forest stand level. However, the greater soil disturbance at the stump harvesting sites enhanced CO{sub 2} production, net nitrogen mineralisation and nitrification. The increased N availability and the changes in microclimate due to the disturbance probably explained the vegetation increase at the stump harvested sites. Planted Norway spruce seedlings grew faster during the first two growing periods at the stump removal sites than at the mounding sites. The seedlings had high and similar ectomycorrhizal colonization rate in both treatments. In the short-term, it is probably not the resources removed in the stumps themselves, but the degree and amount of soil disturbance during the stump harvesting procedure that affects the decomposer community and its function in the clear-felled stands. (orig.)

  19. III-nitride grown on freestanding GaN nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yongjin; Zhu, Hongbo [Institute of Communication Technology, Nanjing University of Posts and Telecommunications, Nanjing, Jiang-Su 210003 (China); Hu, Fangren; Hane, Kazuhiro [Department of Nanomechanics, Tohoku University, Sendai 980-8579 (Japan)

    2012-03-15

    We report here the epitaxial growth of III-nitride on the freestanding GaN nanostructures by molecular beam epitaxy growth. Various GaN nanostructures are defined by electron beam lithography and realized on GaN-on-silicon substrate by fast atom beam etching. Silicon substrate beneath GaN nanostructures is removed from the backside to form the freestanding GaN slab, and the epitaxial growth of III-nitride by MBE is performed on the prepared GaN template. The selective growth takes place with the assistance of GaN nanostructures and generates hexagonal III-nitride pyramids. Thin epitaxial structures, depending on the shape and the size of GaN nanostructure, can produce the promising optical performance. This work opens the way to combine silicon micromachining with the epitaxial growth of III-nitride by MBE on GaN-on-silicon substrate for further integrated optics (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Application of the Stephan et al. Chest Radiograph Comparison Method to Decomposed Human Remains.

    Science.gov (United States)

    Isa, Mariyam I; Hefner, Joseph T; Markey, Michael A

    2017-09-01

    This manuscript describes the use of comparative radiography of the chest to facilitate positive identification of human remains in advanced stages of decomposition. The method reported by Stephan et al. for positive identification of dry, disarticulated skeletal elements was used on semifleshed, decomposing remains. Positive identification was established through multiple points of concordance observed in radiographs of the left and right clavicles and the C5-T1 vertebrae. This case study demonstrates the applicability of the Stephan et al.'s method in cases involving decomposing remains. © 2017 American Academy of Forensic Sciences.

  1. A discrimination-association model for decomposing component processes of the implicit association test.

    Science.gov (United States)

    Stefanutti, Luca; Robusto, Egidio; Vianello, Michelangelo; Anselmi, Pasquale

    2013-06-01

    A formal model is proposed that decomposes the implicit association test (IAT) effect into three process components: stimuli discrimination, automatic association, and termination criterion. Both response accuracy and reaction time are considered. Four independent and parallel Poisson processes, one for each of the four label categories of the IAT, are assumed. The model parameters are the rate at which information accrues on the counter of each process and the amount of information that is needed before a response is given. The aim of this study is to present the model and an illustrative application in which the process components of a Coca-Pepsi IAT are decomposed.

  2. Parameter Optimization Based on GA and HFSS

    Institute of Scientific and Technical Information of China (English)

    SUN Shu-hui; WANG Bing-zhong

    2005-01-01

    A new project based on genetic algorithm (GA) and high frequency simulation software (HFSS) is proposed to optimize microwave passive devices effectively. This project is realized with a general program named as optimization program. The program is compiled by Matlab and the macro language of HFSS which is a fast and effective way to accomplish tasks. In the paper, two examples are used to show the project's feasibility.

  3. Effects of decomposing Rhizophora apiculata leaves on larvae of the shrimp Penaeus monodon

    NARCIS (Netherlands)

    Roijackers, R.M.M.; Nghia, T.T.; Ut, V.N.; Scheffer, M.

    2006-01-01

    We studied the effects of different concentrations of decomposing Rhizophora apiculata leaves and their leachates on larvae of the shrimp Penaeus monodon under laboratory conditions. Shrimp mortality was highly dependent on the concentration of oxygen in the water, which in turn was strongly

  4. Characterization of Phosphate Solubilizing and Potassium Decomposing Strains and Study on their Effects on Tomato Cultivation

    OpenAIRE

    Tin Mar Lynn; Hlaing Swe Win; Ei Phyu Kyaw; Zaw Ko Latt; San San Yu

    2013-01-01

    Seven strains were collected for phosphate solubilizing and potassium decomposing activities from Microbiology Laboratory, Department of Biotechnology, Shweziwa Biofertilizer Plant. When phosphate solubilizing activity of selected strains was qualitatively determined, all strains except from B1 strain, gave clear zone formation on NBRIP media. But when quantitatively determined by spectrophotometric method, all strains solubilized insoluble tricalcium phosphate. Among seven strains, Ps strain...

  5. Effects of decomposing Rhizophora apiculata leaves on larvae of the shrimp Penaeus monodon

    NARCIS (Netherlands)

    Roijackers, R.M.M.; Nghia, T.T.; Ut, V.N.; Scheffer, M.

    2006-01-01

    We studied the effects of different concentrations of decomposing Rhizophora apiculata leaves and their leachates on larvae of the shrimp Penaeus monodon under laboratory conditions. Shrimp mortality was highly dependent on the concentration of oxygen in the water, which in turn was strongly correla

  6. Investigating the Sources of Teachers' Instructional Technology Use through the Decomposed Theory of Planned Behavior

    Science.gov (United States)

    Shiue, Ya-Ming

    2007-01-01

    Based on the decomposed theory of planned behavior, this study used path analysis to examine the relative strength of the factors that influence teachers' use of instructional technology. The study focused on teachers' use of word processors, spreadsheets, presentation software, e-mail, and Web browsers. A path analysis was performed on…

  7. Investigating the Sources of Teachers' Instructional Technology Use through the Decomposed Theory of Planned Behavior

    Science.gov (United States)

    Shiue, Ya-Ming

    2007-01-01

    Based on the decomposed theory of planned behavior, this study used path analysis to examine the relative strength of the factors that influence teachers' use of instructional technology. The study focused on teachers' use of word processors, spreadsheets, presentation software, e-mail, and Web browsers. A path analysis was performed on…

  8. The plant cell wall--decomposing machinery underlies the functional diversity of forest fungi

    Science.gov (United States)

    Daniel C. Eastwood; Dimitrios Floudas; Manfred Binder; Andrzej Majcherczyk; Patrick Schneider; Andrea Aerts; Fred O. Asiegbu; Scott E. Baker; Kerrie Barry; Mika Bendiksby; Melanie Blumentritt; Pedro M. Coutinho; Dan Cullen; Ronald P. de Vries; Allen Gathman; Barry Goodell; Bernard Henrissat; Katarina Ihrmark; Havard Kauserud; Annegret Kohler; Kurt LaButti; Alla Lapidus; Jose L. Lavin; Yong-Hwan Lee; Erika Lindquist; Walt Lilly; Susan Lucas; Emmanuelle Morin; Claude Murat; Jose A. Oguiza; Jongsun Park; Antonio G. Pisabarro; Robert Riley; Anna Rosling; Asaf Salamov; Olaf Schmidt; Jeremy Schmutz; Inger Skrede; Jan Stenlid; Ad Wiebenga; Xinfeng Xie; Ursula Kues; David S. Hibbett; Dirk Hoffmeister; Nils Hogberg; Francis Martin; Igor V. Grigoriev; Sarah C. Watkinson

    2011-01-01

    Brown rot decay removes cellulose and hemicelluloses from wood, residual lignin contributing up to 30% of forest soil carbon, and is derived from an ancestral white rot saprotrophy where both lignin and cellulose are decomposed. Comparative and functional genomics of the “dry rot” fungus Serpula lacrymans, derived from forest ancestors, demonstrated that the evolution...

  9. Natural manganese deposits as catalyst for decomposing hydrogen peroxide (discussion paper)

    NARCIS (Netherlands)

    Knol, A.H.; Lekkerkerker-Teunissen, K.; Van Dijk, J.C.

    2015-01-01

    Drinking water companies more and more implement Advanced Oxidation Processes (AOP) in their treatment schemes to increase the barrier against organic micropollutants (OMPs). It is necessary to decompose the excessive hydrogen peroxide after applying AOP to avoid negative effects in the following,

  10. Decomposing series-parallel graphs into paths of length 3 and triangles

    DEFF Research Database (Denmark)

    Merker, Martin

    2015-01-01

    An old conjecture by Jünger, Reinelt and Pulleyblank states that every 2-edge-connected planar graph can be decomposed into paths of length 3 and triangles, provided its size is divisible by 3. We prove the conjecture for a class of planar graphs including all 2-edge-connected series-parallel gra...

  11. The chemical convergence and decomposer control hypotheses explain solid cattle manure decomposition in production grasslands

    NARCIS (Netherlands)

    Rashid, Muhammad Imtiaz; Lantinga, Egbert A.; Brussaard, Lijbert; Goede, de Ron G.M.

    2017-01-01

    Recently, we reported for the first time that home field advantage (HFA) of litter decomposition also exists in agricultural production systems, in addition to earlier reports from natural ecosystems. Here, we provide evidence that adaptation of the soil decomposer community to differences in the ch

  12. DC Analysis of an Ideal Diode Network Using Its Decomposed Piecevise-Linear Model

    Directory of Open Access Journals (Sweden)

    Z. Kolka

    1994-09-01

    Full Text Available A new method of finding the operating points in circuits containing ideal diodes which utilizes the decomposed form of the state model of an one-dimensional piecewise-linear (PWL system is developed. The universal procedure shown gives all the existing solutions quite automatically.

  13. Acute toxicity of live and decomposing green alga Ulva (Enteromorpha) prolifera to abalone Haliotis discus hannai

    Institute of Scientific and Technical Information of China (English)

    WANG Chao; YU Rencheng; ZHOU Mingjiang

    2011-01-01

    From 2007 to 2009, large-scale blooms of green algae (the so-called "green tides")occurred every summer in the Yellow Sea, China. In June 2008, huge amounts of floating green algae accumulated along the coast of Qingdao and led to mass mortality of cultured abalone and sea cucumber. However, the mechanism for the mass mortality of cultured animals remains undetermined. This study examined the toxic effects of Ulva (Enteromorpha) prolifera, the causative species of green tides in the Yellow Sea during the last three years. The acute toxicity of fresh culture medium and decomposing algal effluent of U. prolifera to the cultured abalone Haliotis discus hannai were tested. It was found that both fresh culture medium and decomposing algal effluent had toxic effects to abalone, and decomposing algal effluent was more toxic than fresh culture medium. The acute toxicity of decomposing algal effluent could be attributed to the ammonia and sulfide presented in the effluent, as well as the hypoxia caused by the decomposition process.

  14. An optimality framework to predict decomposer carbon-use efficiency trends along stoichiometric gradients

    Science.gov (United States)

    Manzoni, S.; Capek, P.; Mooshammer, M.; Lindahl, B.; Richter, A.; Santruckova, H.

    2016-12-01

    Litter and soil organic matter decomposers feed on substrates with much wider C:N and C:P ratios then their own cellular composition, raising the question as to how they can adapt their metabolism to such a chronic stoichiometric imbalance. Here we propose an optimality framework to address this question, based on the hypothesis that carbon-use efficiency (CUE) can be optimally adjusted to maximize the decomposer growth rate. When nutrients are abundant, increasing CUE improves decomposer growth rate, at the expense of higher nutrient demand. However, when nutrients are scarce, increased nutrient demand driven by high CUE can trigger nutrient limitation and inhibit growth. An intermediate, `optimal' CUE ensures balanced growth at the verge of nutrient limitation. We derive a simple analytical equation that links this optimal CUE to organic substrate and decomposer biomass C:N and C:P ratios, and to the rate of inorganic nutrient supply (e.g., fertilization). This equation allows formulating two specific hypotheses: i) decomposer CUE should increase with widening organic substrate C:N and C:P ratios with a scaling exponent between 0 (with abundant inorganic nutrients) and -1 (scarce inorganic nutrients), and ii) CUE should increase with increasing inorganic nutrient supply, for a given organic substrate stoichiometry. These hypotheses are tested using a new database encompassing nearly 2000 estimates of CUE from about 160 studies, spanning aquatic and terrestrial decomposers of litter and more stabilized organic matter. The theoretical predictions are largely confirmed by our data analysis, except for the lack of fertilization effects on terrestrial decomposer CUE. While stoichiometric drivers constrain the general trends in CUE, the relatively large variability in CUE estimates suggests that other factors could be at play as well. For example, temperature is often cited as a potential driver of CUE, but we only found limited evidence of temperature effects

  15. Reaction mechanisms in the organometallic vapor phase epitaxial growth of GaAs

    Science.gov (United States)

    Larsen, C. A.; Buchan, N. I.; Stringfellow, G. B.

    1988-01-01

    The decomposition mechanisms of AsH3, trimethylgallium (TMGa), and mixtures of the two have been studied in an atmospheric-pressure flow system with the use of D2 to label the reaction products which are analyzed in a time-of-flight mass spectrometer. AsH3 decomposes entirely heterogeneously to give H2. TMGa decomposes by a series of gas-phase steps, involving methyl radicals and D atoms to produce CH3D, CH4, C2H6, and HD. TMGa decomposition is accelerated by the presence of AsH3. When the two are mixed, as in the organometallic vapor phase epitaxial growth of GaAs, both compounds decompose in concert to produce only CH4. A likely model is that of a Lewis acid-base adduct that forms and subsequently eliminates CH4.

  16. The Fate of Trace Elements in Yanshan Coal during Fast Pyrolysis

    Directory of Open Access Journals (Sweden)

    Jiatao Dang

    2016-04-01

    Full Text Available In this study, a high-sulfur and high-ash yield coal sample obtained from the Yanshan coalfield in Yunnan, China was analyzed. A series of char samples was obtained by pyrolysis at various temperatures (300, 400, 500, 600, 700, 800, and 900 °C and at a fast heating rate (1000 °C/min. A comprehensive investigation using inductively coupled plasma mass spectrometry (ICP-MS, a mercury analyzer, ion-selective electrode (ISE measurements, X-ray diffraction (XRD analysis, and Fourier transform infrared (FTIR spectroscopy was performed to reveal the effects of the pyrolysis temperature on the transformation behavior of trace elements (TEs and the change in the mineralogical characteristics and functional groups in the samples. The results show that the TE concentrations in the raw coal are higher than the average contents of Chinese coal. The concentrations of Be, Li, and U in the char samples are higher than those in raw coal, while the opposite was observed for As, Ga, Hg, and Rb. The F and Se concentrations are initially higher but decrease with pyrolysis temperature, which is likely caused by associated fracturing with fluoride and selenide minerals. Uranium shows the highest enrichment degree, and Hg shows the highest volatilization degree compared to the other studied TEs. As the temperature increases, the number of OH groups decreases, and the mineral composition changes; for example, pyrite decomposes, while oldhamite and hematite occur in the chars. It is suggested that the behavior and fate of TEs in coal during fast pyrolysis are synergistically influenced by self-characteristic modes of occurrence and mineralogical characteristics.

  17. (Asynchronous availabilities of N and P regulate the activity and structure of the microbial decomposer community

    Directory of Open Access Journals (Sweden)

    Nicolas eFanin

    2016-01-01

    Full Text Available Nitrogen (N and phosphorus (P availability both control microbial decomposers and litter decomposition. However, these two key nutrients show distinct release patterns from decomposing litter and are unlikely available at the same time in most ecosystems. Little is known about how temporal differences in N and P availability affect decomposers and litter decomposition, which may be particularly critical for tropical rainforests growing on old and nutrient-impoverished soils. Here we used three chemically contrasted leaf litter substrates and cellulose paper as a widely accessible substrate containing no nutrients to test the effects of temporal differences in N and P availability in a microcosm experiment under fully controlled conditions. We measured substrate mass loss, microbial activity (by substrate induced respiration, SIR as well as microbial community structure (using phospholipid fatty acids, PLFAs in the litter and the underlying soil throughout the initial stages of decomposition. We generally found a stronger stimulation of substrate mass loss and microbial respiration, especially for cellulose, with simultaneous NP addition compared to a temporally separated N and P addition. However, litter types with a relatively high N to P availability responded more to initial P than N addition and vice versa. A third litter species showed no response to fertilization regardless of the sequence of addition, likely due to strong C limitation. Microbial community structure in the litter was strongly influenced by the fertilization sequence. In particular, the fungi to bacteria ratio increased following N addition alone, a shift that was reversed with complementary P addition. Opposite to the litter layer microorganisms, the soil microbial community structure was more strongly influenced by the identity of the decomposing substrate than by fertilization treatments, reinforcing the idea that C availability can strongly constrain decomposer

  18. Growth and characterization of metamorphic InAs/GaSb tunnel heterojunction on GaAs by molecular beam epitaxy

    Science.gov (United States)

    Liu, Jheng-Sin; Clavel, Michael B.; Pandey, Rahul; Datta, Suman; Meeker, Michael; Khodaparast, Giti A.; Hudait, Mantu K.

    2016-06-01

    The structural, morphological, optical, and electrical transport characteristics of a metamorphic, broken-gap InAs/GaSb p-i-n tunnel diode structure, grown by molecular beam epitaxy on GaAs, were demonstrated. Precise shutter sequences were implemented for the strain-balanced InAs/GaSb active layer growth on GaAs, as corroborated by high-resolution X-ray analysis. Cross-sectional transmission electron microscopy and detailed micrograph analysis demonstrated strain relaxation primarily via the formation of 90° Lomer misfit dislocations (MDs) exhibiting a 5.6 nm spacing and intermittent 60° MDs at the GaSb/GaAs heterointerface, which was further supported by a minimal lattice tilt of 180 arc sec observed during X-ray analysis. Selective area diffraction and Fast Fourier Transform patterns confirmed the full relaxation of the GaSb buffer layer and quasi-ideal, strain-balanced InAs/GaSb heteroepitaxy. Temperature-dependent photoluminescence measurements demonstrated the optical band gap of the GaSb layer. Strong optical signal at room temperature from this structure supports a high-quality material synthesis. Current-voltage characteristics of fabricated InAs/GaSb p-i-n tunnel diodes measured at 77 K and 290 K demonstrated two bias-dependent transport mechanisms. The Shockley-Read-Hall generation-recombination mechanism at low bias and band-to-band tunneling transport at high bias confirmed the p-i-n tunnel diode operation. This elucidated the importance of defect control in metamorphic InAs/GaSb tunnel diodes for the implementation of low-voltage and high-performance tunnel field effect transistor applications.

  19. GA-Gammon

    DEFF Research Database (Denmark)

    Irineo-Fuentes, Oscar; Cruz-Cortes, Nareli; Rodriguez-Henriquez, Francisco

    2006-01-01

    of the best board positions during a game. Best GA-Gammon individuals so obtained were tested in separated 5000-game tournaments against Pubeval itself, and Fuzzeval, a fuzzy controller-based player. Our experimental results indicate that the best individuals generated by GA-Gammon show similar performance...

  20. Root-induced decomposer growth and plant N uptake are not positively associated among a set of grassland plants

    DEFF Research Database (Denmark)

    Saj, S.; Mikola, J.; Ekelund, Flemming

    2008-01-01

    lanceolata and a leguminous herb Lotus corniculatus. We further predicted that (2) in terms of litter-N uptake those plant species that induce lower abundance of decomposers benefit from sharing soil with species inducing higher decomposer abundance. To test this, we grew the three plant species in two....... corniculatus induced the highest abundance of decomposers, H. lanatus had the highest uptake of N from the litter, which refuted our first prediction. Since this prediction was falsified, we could not properly test the second one, but we found that litter-N uptake of H. lanatus and P. lanceolata were...... not significantly affected by the presence of L. corniculatus and the higher abundance of decomposers induced by L. corniculatus roots. Our results show that among the three plant species tested root-induced decomposer growth and plant N uptake from soil organic matter were not positively associated. It appears...

  1. A Semantic-Based Approach for Detecting and Decomposing God Classes

    CERN Document Server

    Lee, Junha; Kim, Dae-Kyoo; Park, Sooyong

    2012-01-01

    Cohesion is a core design quality that has a great impact on posterior development and maintenance. By the nature of software, the cohesion of a system is diminished as the system evolves. God classes are code defects resulting from software evolution, having heterogeneous responsibilities highly coupled with other classes and often large in size, which makes it difficult to maintain the system. The existing work on identifying and decomposing God classes heavily relies on internal class information to identify God classes and responsibilities. However, in object-oriented systems, responsibilities should be analyzed with respect to not only internal class information, but also method interactions. In this paper, we present a novel approach for detecting God classes and decomposing their responsibilities based on the semantics of methods and method interactions. We evaluate the approach using JMeter v2.5.1 and the results are promising.

  2. Estimating biological elementary flux modes that decompose a flux distribution by the minimal branching property

    DEFF Research Database (Denmark)

    Chan, Siu Hung Joshua; Solem, Christian; Jensen, Peter Ruhdal;

    2014-01-01

    MOTIVATION: Elementary flux mode (EFM) is a useful tool in constraint-based modeling of metabolic networks. The property that every flux distribution can be decomposed as a weighted sum of EFMs allows certain applications of EFMs to studying flux distributions. The existence of biologically...... infeasible EFMs and the non-uniqueness of the decomposition, however, undermine the applicability of such methods. Efforts have been made to find biologically feasible EFMs by incorporating information from transcriptional regulation and thermodynamics. Yet, no attempt has been made to distinguish...... reduced the solution space in which the decomposition is often unique. An experimental flux distribution from a previous study on mouse cardiomyocyte was decomposed using MBD. Comparison with decomposition by a minimum number of EFMs showed that MBD found EFMs more consistent with established biological...

  3. HOW DO DEGRADABLE/BIODEGRADABLE PLASTIC MATERIALS DECOMPOSE IN HOME COMPOSTING ENVIRONMENT?

    Directory of Open Access Journals (Sweden)

    Magdalena Vaverková

    2014-10-01

    Full Text Available This paper provides information about biodegradability of polymeric (biodegradable/degradable materials advertised as 100%-degradable or certified as compostable, which may be a part of biodegradable waste, in home composting conditions. It describes an experiment that took place in home wooden compost bins and contained 9 samples that are commonly available in retail chains in the Czech Republic and Poland. The experiment lasted for the period of 12 weeks. Based on the results thereof it can be concluded that polyethylene samples with additive (samples 2, 4, 7 have not decomposed, their color has not changed and that no degradation or physical changes have occurred. Samples 1, 3 and 5 certified as compostable have not decomposed. Sample 6 exhibited the highest decomposition rate. Samples 8, 9 (tableware exhibited high degree of decomposition. The main conclusion from this study is that degradable/biodegradable plastics or plastics certified as compostable are not suitable for home composting.

  4. Does nutrient enrichment compensate fungicide effects on litter decomposition and decomposer communities in streams?

    Science.gov (United States)

    Fernández, Diego; Tummala, Mallikarjun; Schreiner, Verena C; Duarte, Sofia; Pascoal, Cláudia; Winkelmann, Carola; Mewes, Daniela; Muñoz, Katherine; Schäfer, Ralf B

    2016-05-01

    Nutrient and pesticide pollution are widespread agricultural stressors. Fungicides may affect freshwater fungi, which play an important role in litter decomposition (LD), whereas moderate nutrient enrichment can stimulate LD. We examined potential interaction effects of nutrients and fungicides on decomposer communities and LD in a 14-day two-factorial (fungicide and nutrient treatments) mesocosm experiment. Fungicide exposure was limited to 4days to simulate episodic contamination. Only the microbial community responded significantly to the experimental factors, though non-significant increases >20% were found for invertebrate decomposer weight gain and LD under high-nutrient conditions. Fungal community structure responded more strongly to fungicides than sporulation. Sporulation responded strongest to nutrients. Bacterial community structure was affected by both factors, although only nutrients influenced bacterial density. Our results suggest effects from fungicides at field-relevant levels on the microbial community. Whether these changes propagate to invertebrate communities and LD remains unclear and should be analysed under longer and recurrent fungicide exposure.

  5. Conversion of organic carbon in the decomposable organic wastes in anaerobic lysimeters under different temperatures

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The quantitative fractions of conversion of organic carbon in the decomposable organic wastes with initial moisture of 70% sorted from municipal solid wastes(MSW) in lysimeters into biogas, leachate and solid residue were characterized, under temperatures of 25, 30 and 41℃, respectively, and circulation of leachate generated within the lysimeters. It is found that 27% of organic carbon in the wastes are conversed into gases, 0.8% into leachate, and the other 72% remained in the decomposable solid residues, after 180 days' degradation at 41℃. Higher temperature will lead to more rapid degradation and result to higher conversion of the organic carbon to biogas and lower to both solid residues and leachate, while the pollutant concentrations in leachate will be lower at a higher temperature and the values of COD are quite consistent with TOC.

  6. Why does Kevlar decompose, while Nomex does not, when treated with aqueous chlorine solutions?

    Science.gov (United States)

    Akdag, Akin; Kocer, Hasan B; Worley, S D; Broughton, R M; Webb, T R; Bray, Travis H

    2007-05-24

    Kevlar and Nomex are high-performance polymers which have wide varieties of applications in daily life. Recently, they have been proposed to be biocidal materials when reacted with household bleach (sodium hypochlorite solution) because they contain amide moieties which can be chlorinated to generate biocidal N-halamine functional groups. Although Nomex can be chlorinated without any significant decomposition, Kevlar decomposes under the same chlorination conditions. In this study, two mimics for each of the polymers were synthesized to simulate the carboxylate and diaminophenylene components of the materials. It was found that the p-diaminophenylene component of the Kevlar mimic is oxidized to a quinone-type structure upon treatment with hypochlorous acid, which then decomposes. However, such a mechanism for the Nomex mimic is not possible. In this paper, based upon these observations, a plausible answer will be provided to the title question.

  7. Different pathways but same result? Comparing chemistry and biological effects of burned and decomposed litter

    Science.gov (United States)

    Mazzoleni, Stefano; Bonanomi, Giuliano; Incerti, Guido; El-Gawad, Ahmed M. Abd; Sarker, Tushar Chandra; Cesarano, Gaspare; Saulino, Luigi; Saracino, Antonio; Castro Rego, Francisco

    2017-04-01

    Litter burning and biological decomposition are oxidative processes co-occurring in many terrestrial ecosystems, producing organic matter with different chemical properties and differently affecting plant growth and soil microbial activity. Here, we tested the chemical convergence hypothesis (i.e. materials with different initial chemistry tend to converge towards a common profile, with similar biological effects, as the oxidative process advances) for burning and decomposition. We compared the molecular composition of 63 organic materials - 7 litter types either fresh, decomposed for 30, 90, 180 days, or heated at 100, 200, 300, 400, 500 °C - as assessed by 13C NMR. We used litter water extracts (5% dw) as treatments in bioassays on plant (Lepidium sativum) and fungal (Aspergillus niger) growth, and a washed quartz sand amended with litter materials (0.5 % dw) to assess heterotrophic respiration by CO2 flux chamber. We observed different molecular variations for materials either burning (i.e. a sharp increase of aromatic C and a decrease of most other fractions above 200 °C) or decomposing (i.e. early increase of alkyl, methoxyl and N-alkyl C and decrease of O-alkyl and di-O-alkyl C fractions). Soil respiration and fungal growth progressively decreased with litter age and temperature. Plant growth underwent an inhibitory effect by untreated litter, more and less rapidly released over decomposing and burning materials, respectively. Correlation analysis between NMR and bioassay data showed that opposite responses for soil respiration and fungi, compared to plants, are related to essentially the same C molecular types. Our findings suggest a functional convergence of decomposed and burnt organic substrates, emerging from the balance between the bioavailability of labile C sources and the presence of recalcitrant and pyrogenic compounds, oppositely affecting different trophic levels.

  8. Geometry Theorem Proving by Decomposing Polynomial System into Strong Regular Sets

    Institute of Scientific and Technical Information of China (English)

    Yong-Bin Li; Wu Liu; Xiao-Lin Xiang

    2004-01-01

    This paper presents a complete method to prove geometric theorem by decomposing the corresponding polynomial system into strong regular sets, by which one can compute some components for which the geometry theorem is true and exclude other components for which the geometry theorem is false. Two examples are given to show that the geometry theorems are conditionally true for some components which are excluded by other methods.

  9. An algorithm for decomposing a polynomial system into normal ascending sets

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We present an algorithm to decompose a polynomial system into a finite set of normal ascending sets such that the set of the zeros of the polynomial system is the union of the sets of the regular zeros of the normal ascending sets. If the polynomial system is zero dimensional, the set of the zeros of the polynomials is the union of the sets of the zeros of the normal ascending sets.

  10. Decomposing productivity growth in OECD countries: domestic R&D vs. international technology diffusion

    OpenAIRE

    Jakub Growiec; Lukasz Marc; Dorota Pelle

    2009-01-01

    This paper decomposes productivity growth across highly developed OECD countries in the period 1972-2000 into components attributable to domestic R&D output, a catchup effect, and international technology diffusion via imports of hi-tech products. Two alternative specifications of “productivity growth” are considered: (i) increments of the conventional residual measure of total factor productivity (computed under the assumption that the production function takes both physical and human capita...

  11. Decomposing the Riskiness of Corporate Foreign Currency Lending: the Case of Hungary

    OpenAIRE

    Vonnák, Dzsamila

    2015-01-01

    I decompose the factors contributing to the riskiness of foreign currency borrowers. I compare counterfactual default probabilities of local and foreign currency borrowers estimated on disaggregated data. My results suggest that the currency mismatch with the depreciation of the local currency is the most important factor contributing to the riskiness of foreign currency borrowers, though boom-period excessive risk taking of banks is also concentrated in foreign currency lending.

  12. Vertical distribution of phosphorus and P-dissolving/decomposing bacteria in the sediment of Guanting reservoir

    Institute of Scientific and Technical Information of China (English)

    LI; Cui; YUAN; Hongli; HUANG; Huaizeng

    2005-01-01

    In this study, we determined pH, phosphorus content and the number of P-dis- solving/decomposing bacteria in relation to the depth in the sediment of Guanting reservoir in Beijing. The pH value was slightly increased from 8.0 in the surface to 8.5 in the bottle (69 cm in depth) of sediment. The highest P content, 1269 mg/kg, was detected in the 35 cm layer, followed by the 5 cm (993 mg/kg) and 69 cm (580 mg/kg) layers. The number of inorganic P-dissolving bacteria varied from 6(102 to 8(104 and the organic P-discomposing bacteria were from 1.9(103 to 6.3(104 per gram sediment in different depths, which were counted under 28℃ and 20℃ ( pH7.5 and 8.5. The number of P-dissolving/discomposing bacteria was directly correlated to the P content in each layer of sediments. The analysis of P-dissolving/decomposing ability of bacteria showed that some of these bacteria were also capable of accumulating P intracellularly. The intracellular P-accumulation was more efficient at lower temperature; in contrast, the activity of P-dissolving/decomposing was stronger at higher temperature. So the content of dissolved P in water body, or quality of water, could be affected by the change of temperature via the regulation of bacterial activity. On the basis of 16S rDNA sequencing, the 13 efficient P-dis- solving/decomposing bacteria were identified as Bacillus spp., Bacterium sp., Microbacterium sp., Paenibacillus sp. and Pseudomonas sp.

  13. Recurrently decomposable 2-D convolvers for FPGA-based digital image processing

    OpenAIRE

    Ma' Yang, De; Liu; Bharath, AA

    2016-01-01

    Two-dimensional (2-D) convolution is a widely used operation in image processing and computer vision, characterized by intensive computation and frequent memory accesses. Previous efforts to improve the performance of field-programmable gate array (FPGA) convolvers focused on the design of buffering schemes and on minimizing the use of multipliers. A recently proposed recurrently decomposable (RD) filter design method can reduce the computational complexity of 2-D convolutions by splitting th...

  14. An initial study of insect succession on decomposing rabbit carrions in Harare, Zimbabwe

    Institute of Scientific and Technical Information of China (English)

    Nyasha Mabika; Ron Masendu; Gilbert Mawera

    2014-01-01

    Objective: To investigate insects visiting sun exposed and shaded decomposing rabbit carcasses and to establish the relationship between insects and carcasses which may be of forensic importance in Harare. Methods: Two rabbits weighing 2.3 kg and 2.5 kg were killed by sharp blows on the head. One was exposed to the sun while the other was placed under shade. The carcasses were allowed to decompose and insects were collected twice a day for the first week and thereafter once a day up to the end of the 7 weeks. Maggots were also collected from the decomposing carcasses and reared.Results:Five dipteran families (Calliphoridae, Muscidae, Sarcophagidae, Phoridae and Drosophilidae) were identified from the sun-exposed carcass. Species collected included Luciliacuprina (L. cuprina), Chrysomya albiceps (C. albiceps), Musca domestica, Sarcophaga sp. and Drosophila sp. Four families (Calliphoridae, Muscidae, Phoridae, Anthomyiidae) were identified from the shaded carcass. Representatives of these families included L. cuprina, C. albiceps, Musca domestica, and Hydrotaea sp. Three Coleopteran families (Histeridae, Cleridae and Dermestidae) were identified from both carcasses. The observed species were Saprinus sp., Necrobia rufipes and Dermestes sp. Formicidae (Hymenoptera) was represented by only one species (Pheidole sp.). Flies which emerged from the rearing units were L. cuprina, Lucilia sp., C. albiceps, Sarcophaga sp. and Sepsis sp.). Conclusions: Of the dipteran species collected during the study, L. cuprina and C. albiceps could be important for further forensic studies since they were collected from the carcasses and also observed from the rearing units.

  15. Programmed cell death in Laminaria japonica (Phaeophyta) tissues infected with alginic acid decomposing bacterium

    Institute of Scientific and Technical Information of China (English)

    WANG Gaoge; LIN Wei; ZHANG Lijing; YAN Xiaojun; DUAN Delin

    2004-01-01

    TdT-mediated dUTP-biotin nick end labeling (TUNEL) is a sensitive and valid method for detecting DNA cleavage in programmed cell death (PCD). Using this method, DNA cleavage was observed in Laminaria japonica sporophytic tissues, which were infected with alginic acid decomposing bacterium. It was found that DNA cleavage occurred 5 min after the infection, the fragments with 3′-OH groups of cleaved nuclear DNA increased with time of infection and spread from the infection site. Although no typical DNA ladder (200 bp/180 bp) was detected by routine agarose gel electrophoresis, the cleavage of nuclear DNA fragments of 97~48.5 kb could be detected by pulsed field gel electrophoresis (PFGE). By using CaspGLOWTM fluorescein active caspase-3 staining method, caspase-3 activity has been detected in response to the infection of alginic acid decomposing bacterium. Our results are similar to the observations in hypersensitive response (HR) of higher plant, suggesting that the rapid cell death of L. Japonica infected by alginic acid decomposing bacterium might be involved in PCD, and indicating that the occurrence of PCD is an active defense process against the pathogen's infection.

  16. GaAs/GaSb nanowire heterostructures grown by MOVPE

    DEFF Research Database (Denmark)

    Jeppsson, Mattias; Dick, Kimberly A.; Wagner, Jakob Birkedal

    2008-01-01

    We report Au-assisted growth of GaAs/GaSb nanowire heterostructures on GaAs(1 1 1)B-substrates by metal-organic vapor phase epitaxy. The growth is studied at various precursor molar fractions and temperatures, in order to optimize the growth conditions for the GaSb nanowire segment. In contrast t...

  17. Study of piezoelectric field in GaN quantum discs embedded in AlGaN nanocolumns

    Energy Technology Data Exchange (ETDEWEB)

    Zamfirescu, Marian; Gurioli, Massimo; Vinattieri, Anna [CNISM, Dipartimento di Fisica and LENS, Universita' di Firenze, via Sansone 1, 50019, Sesto Fiorentino (Italy); Risti, J.; Calleja, E. [Dept. Ingenieria Electronica, ETSI Telecomunicacion-ISOM, Universidad Politecnica, Ciudad Universitaria, Madrid 28040 (Spain)

    2005-11-01

    We report on recombination kinetics, by means of time resolved photoluminescence technique, on GaN quantum discs embedded in strain free AlGaN nanocolumn. The emission of the 100 Aa QD shows a very long time decay (about 20 ns), denoting a small radiative rate; in contrast, fast decay time are observed in the case of 20 Aa disc ({proportional_to}450 ps). At the same time a large blue shift of the PL band is found in the 100 Aa QD when increasing the power excitation while the PL of the 20 Aa QD does not show any energy shift. The whole phenomenology can be interpreted in terms of piezoelectric polarization fields inside the strained GaN QDs embedded in relaxed AlGaN nanocolumn (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Flash chemistry: fast chemical synthesis by using microreactors.

    Science.gov (United States)

    Yoshida, Jun-ichi; Nagaki, Aiichiro; Yamada, Takeshi

    2008-01-01

    This concept article provides a brief outline of the concept of flash chemistry for carrying out extremely fast reactions in organic synthesis by using microreactors. Generation of highly reactive species is one of the key elements of flash chemistry. Another important element of flash chemistry is the control of extremely fast reactions to obtain the desired products selectively. Fast reactions are usually highly exothermic, and heat removal is an important factor in controlling such reactions. Heat transfer occurs very rapidly in microreactors by virtue of a large surface area per unit volume, making precise temperature control possible. Fast reactions often involve highly unstable intermediates, which decompose very quickly, making reaction control difficult. The residence time can be greatly reduced in microreactors, and this feature is quite effective in controlling such reactions. For extremely fast reactions, kinetics often cannot be used because of the lack of homogeneity of the reaction environment when they are conducted in conventional reactors such as flasks. Fast mixing using micromixers solves such problems. The concept of flash chemistry has been successfully applied to various organic reactions including a) highly exothermic reactions that are difficult to control in conventional reactors, b) reactions in which a reactive intermediate easily decomposes in conventional reactors, c) reactions in which undesired byproducts are produced in the subsequent reactions in conventional reactors, and d) reactions whose products easily decompose in conventional reactors. The concept of flash chemistry can be also applied to polymer synthesis. Cationic polymerization can be conducted with an excellent level of molecular-weight control and molecular-weight distribution control.

  19. Formation, atomic structure, and electronic properties of GaSb quantum dots in GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Timm, R.

    2007-12-14

    In this work, cross-sectional scanning tunneling microscopy and spectroscopy are used for the first time to study the shape, size, strain, chemical composition, and electronic properties of capped GaSb/GaAs QDs at the atomic scale. By evaluating such structural results on a variety of nanostructures built using different epitaxy methods and growth conditions, details on the underlying QD formation processes can be revealed. A cross-over from flat quantum wells (QWs) to optically active QDs can be observed in samples grown by metalorganic chemical vapor deposition (MOCVD) with increasing amount of GaSb, including self-assembled Sb accumulations within a still two-dimensional layer and tiny three-dimensional GaSb islands probably acting as precursor structures. The QWs consist of significantly intermixed material with stoichiometries of maximally 50% GaSb, additionally exhibiting small gaps filled with GaAs. A higher GaSb content up to nearly pure material is found in the QDs, being characterized by small sizes of up to 8 nm baselength and about 2 nm height. In spite of the intermixing, all nanostructures have rather abrupt interfaces, and no significant Sb segregation in growth direction is observed. This changes completely when molecular beam epitaxy (MBE) is used as growth method, in which case individual Sb atoms are found to be distributed over several nm above the nanostructures. Massive group-V atomic exchange processes are causing this strong inter-mixing and Sb segregation during GaAs overgrowth. In combination with the large strain inherent to GaSb/GaAs QDs, this segregation upon overgrowth is assumed to be the reason for a unique structural phenomenon: All MBE-grown QDs, independent of the amount of deposited GaSb, exhibit a ring structure, consisting of a ring body of high GaSb content and a more or less extended central gap filled with GaAs. These rings have formed in a self-assembled way even when the initial GaSb layer was overgrown considerably fast

  20. GaN HEMTs

    Science.gov (United States)

    Anderson, Jonathan W.; Lee, Kyoung-Keun; Piner, Edwin L.

    2012-03-01

    Gallium nitride (GaN) has enormous potential for applications in high electron mobility transistors (HEMTs) used in RF and power devices. Intrinsic device properties such as high electron mobility, high breakdown voltage, very high current density, electron confinement in a narrow channel, and high electron velocity in the 2-dimensional electron gas of the HEMT structure are due in large part to the wide band gap of this novel semiconductor material system. This presentation discusses the properties of GaN that make it superior to other semiconductor materials, and outlines the research that will be undertaken in a new program at Texas State University to advance GaN HEMT technology. This program's aim is to further innovate the exceptional performance of GaN through improved material growth processes and epitaxial structure design.

  1. An initial study of insect succession on decomposing rabbit carrions in Harare,Zimbabwe

    Institute of Scientific and Technical Information of China (English)

    Nyasha; Mabika; Ron; Masendu; Gilbert; Mawera

    2014-01-01

    Objective:To investigate insects visiting sun exposed and shaded decomposing rabbit carcasses and to establish the relationship between insects and carcasses which may be of forensic importance in Harare.Methods:Two rabbits weighing 2.3 kg and 2.5 kg were killed by sharp blows on the head.One was exposed to the sun while the other was placed under shade.The carcasses were allowed to decompose and insects were collected twice a day for the first week and thereafter once a day up to the end of the 7 weeks.Maggots were also collected from the decomposing carcasses and reared.Results:Five dipteran families(Galliphoridae,Muscidae,Sarcophagidae,Phoridae and Drosophilidae)were identified from the sun-exposed carcass.Species collected included Lucilia cuprina(L.cuprina),Chrysomya albiceps(C.albiceps),Musca domestica,Sarcophaga sp.and Drosophila sp.Four families(Calliphoridae,Muscidae,Phoridae,Anthomyiidae)were identified from the shaded carcass.Representatives of these families included L cuprina,C.albiceps,Musca domestica,and Hydrotaea sp.Three Coleopteran families(Histeridae,Cleridae and Dermestidae)were identified from hodt carcasses.The observed species were Saprinus sp,Necrobia rufipes and Dermestes sp.Fomicidae(Hymenoptera)was represented by only one species(Pheidoie sp.)Flies which emerged from the rearing units were L cuprina,Lucilia sp.,C.albiceps,Sarcophaga sp.and Sepsis sp.).Conclusions:Of the dipteran species collected during the study,L cuprina and C.albiceps could be important for further forensic studies since they were collected from the carcasses and also observed from the rearing units.

  2. ASSETS MANAGEMENT - A CONCEPTUAL MODEL DECOMPOSING VALUE FOR THE CUSTOMER AND A QUANTITATIVE MODEL

    Directory of Open Access Journals (Sweden)

    Susana Nicola

    2015-03-01

    Full Text Available In this paper we describe de application of a modeling framework, the so-called Conceptual Model Decomposing Value for the Customer (CMDVC, in a Footwear Industry case study, to ascertain the usefulness of this approach. The value networks were used to identify the participants, both tangible and intangible deliverables/endogenous and exogenous assets, and the analysis of their interactions as the indication for an adequate value proposition. The quantitative model of benefits and sacrifices, using the Fuzzy AHP method, enables the discussion of how the CMDVC can be applied and used in the enterprise environment and provided new relevant relations between perceived benefits (PBs.

  3. Decomposing Gender Equality along the Wage Distribution in Vietnam during the Period 2002–14

    OpenAIRE

    Tien Manh , VU; Hiroyuki, YAMADA

    2017-01-01

    In this paper, we decompose the gender wage gap along the wage distribution in Vietnam during the period 2002–14 and search for the presence of a glass ceiling/sticky floor in wages using the method proposed by Chernozhukov, Fernandez-Val, and Melly (2013). We focus on the formal sector and further divide the sample by educational level, age profile, occupational type, and industry. We find evidence for a total gender wage gap with the price of skills (the price gap) being the main contributo...

  4. Synthesis and Characterization of Cadmium Sulfide Nanoparticles via a Simple Thermal Decompose Method

    Science.gov (United States)

    Seyghalkar, Hamideh; Sabet, Mohammad; Salavati-Niasari, Masoud

    2016-11-01

    In this work, cadmium sulfide (CdS) nanoparticles were synthesized from a new Cd-octanoate complex via a simple thermal decompose method. The crystallinity of the product was obtained from X-ray diffraction (XRD) pattern. The morphology and product size were analyzed via scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Also Fourier transform infrared (FT-IR) spectroscopy was used to investigate the CdS surface purity. Finally, the optical properties of the product were obtained from photoluminescence (PL) spectroscopy.

  5. Decomposing highly edge-connected graphs into homomorphic copies of a fixed tree

    DEFF Research Database (Denmark)

    Merker, Martin

    2016-01-01

    The Tree Decomposition Conjecture by Barát and Thomassen states that for every tree T there exists a natural number k(T) such that the following holds: If G is a k(T)-edge-connected simple graph with size divisible by the size of T, then G can be edge-decomposed into subgraphs isomorphic to T. So...... far this conjecture has only been verified for paths, stars, and a family of bistars. We prove a weaker version of the Tree Decomposition Conjecture, where we require the subgraphs in the decomposition to be isomorphic to graphs that can be obtained from T by vertex-identifications. We call...

  6. A decomposing technique for scheelite concentrate and low-grade scheelite concentrate

    Institute of Scientific and Technical Information of China (English)

    HUO Guangsheng; SUN Peimei; LI Honggui; LI Yunjiao; ZHAO Zhongwei; SUN Zhaoming; LIU Maosheng

    2004-01-01

    The effect of different decomposition conditions on tungsten recovery for scheelite concentrate has been examined. The results show that tungsten recovery can be more than 98% under decomposing conditions as follows: the amount of caustic soda is 2.2 and 3.2 times of theoretical respectively, ratio of water and ore is 0.7-0.8, temperature is 160℃, and preservation time is 2.0 h for scheelite concentrate (63.21% WO3) and low grade scheelite concentrate (55.17% WO3).

  7. Multi-Temporal Decomposed Wind and Load Power Models for Electric Energy Systems

    Science.gov (United States)

    Abdel-Karim, Noha

    This thesis is motivated by the recognition that sources of uncertainties in electric power systems are multifold and may have potentially far-reaching effects. In the past, only system load forecast was considered to be the main challenge. More recently, however, the uncertain price of electricity and hard-to-predict power produced by renewable resources, such as wind and solar, are making the operating and planning environment much more challenging. The near-real-time power imbalances are compensated by means of frequency regulation and generally require fast-responding costly resources. Because of this, a more accurate forecast and look-ahead scheduling would result in a reduced need for expensive power balancing. Similarly, long-term planning and seasonal maintenance need to take into account long-term demand forecast as well as how the short-term generation scheduling is done. The better the demand forecast, the more efficient planning will be as well. Moreover, computer algorithms for scheduling and planning are essential in helping the system operators decide what to schedule and planners what to build. This is needed given the overall complexity created by different abilities to adjust the power output of generation technologies, demand uncertainties and by the network delivery constraints. Given the growing presence of major uncertainties, it is likely that the main control applications will use more probabilistic approaches. Today's predominantly deterministic methods will be replaced by methods which account for key uncertainties as decisions are made. It is well-understood that although demand and wind power cannot be predicted at very high accuracy, taking into consideration predictions and scheduling in a look-ahead way over several time horizons generally results in more efficient and reliable utilization, than when decisions are made assuming deterministic, often worst-case scenarios. This change is in approach is going to ultimately require new

  8. GaSbBi/GaSb quantum well laser diodes

    Science.gov (United States)

    Delorme, O.; Cerutti, L.; Luna, E.; Narcy, G.; Trampert, A.; Tournié, E.; Rodriguez, J.-B.

    2017-05-01

    We report on the structural and optical properties of GaSbBi single layers and GaSbBi/GaSb quantum well heterostructures grown by molecular beam epitaxy on GaSb substrates. Excellent crystal quality and room-temperature photoluminescence are achieved in both cases. We demonstrate laser operation from laser diodes with an active zone composed of three GaSb0.885Bi0.115/GaSb quantum wells. These devices exhibit continuous-wave lasing at 2.5 μm at 80 K, and lasing under pulsed operation at room-temperature near 2.7 μm.

  9. SFC Optimization for Aero Engine Based on Hybrid GA-SQP Method

    Science.gov (United States)

    Li, Jie; Fan, Ding; Sreeram, Victor

    2013-12-01

    This study focuses on on-line specific fuel consumption (SFC) optimization of aero engines. For solving this optimization problem, a nonlinear pneumatic and thermodynamics model of the aero engine is built and a hybrid optimization technique which is formed by combining the genetic algorithm (GA) and the sequential quadratic programming (SQP) is presented. The ability of standard GA and standard SQP in solving this type of problem is investigated. It has been found that, although the SQP is fast, very little SFC reductions can be obtained. The GA is able to solve the problem well but a lot of computational time is needed. The presented hybrid GA-SQP gives a good SFC optimization effect and saves 76.6% computational time when compared to the standard GA. It has been shown that the hybrid GA-SQP is a more effective and higher real-time method for SFC on-line optimization of the aero engine.

  10. Pemanfaatan Kompos Campuran Manure Ayam Broiler dan Limbah Kulit Kopi dengan Berbagai Dosis MOD (Microorganisme Decomposer) Terhadap Pertumbuhan Indigofera zollingeriana

    OpenAIRE

    Lubis, Putri Anggun Rumondang

    2017-01-01

    This study aims to determine effects of utilization of broilers chicken manure compost mixed and leather waste coffee with various dosage MOD (microorganisme decomposer) on production of indigofera zollingeriana. Research conducted at the farm experimental Faculty of Agriculture Departmen of Animal Husbandry University of North Sumatra in April-November 2016. The design used in the study was split plot design with four replications. First factor (M): dosage decomposer (liters/ton), M1= 1 and ...

  11. Epitaxial Growth of GeGaAs.

    Science.gov (United States)

    1981-06-01

    liquid solvent for epitaxial growth of Ge. Because of the finite solubility of GaAs in Pb (7 x 10-4 atomic fraction at 500°C) relatively fast initial...mixture of Pb and Sn was used as a melt. The solubility of Ge in a PbSn eutetic mixture is significantly higher than the solubility of Ge in pure Pb...shallow donor acceptor levels. Addition of a deep level to the crystal lat- tice at this point would further pin the fermi level near mid-gap

  12. Unintentional gallium incorporation in InGaN layers during epitaxial growth

    Science.gov (United States)

    Zhou, Kun; Ren, Huaijin; Ikeda, Masao; Liu, Jianping; Ma, Yi; Gao, Songxin; Tang, Chun; Li, Deyao; Zhang, Liquan; Yang, Hui

    2017-01-01

    Unintentional gallium incorporation was observed and investigated in the epitaxial growth of InGaN by metalorganic vapor phase epitaxy. InGaN was grown without intentional gallium precursor and the gallium incorporation rate was found not dependent on TEGa source but was significantly influenced by temperature and TMIn source flow. The source of the unintentional gallium incorporation is confirmed to be from the flow distributor of the reactor. The incorporation mechanism was analyzed to be the diffusion of resultant of transmetalation reaction between TMIn or its decomposed products (for example DMIn) and residual gallium. Due to the unintentional gallium incorporation, the growth rate and indium content of InGaN layer are determined by indium source, gallium source and the growth temperature.

  13. First-principles study of SF6 decomposed gas adsorbed on Au-decorated graphene

    Science.gov (United States)

    Zhang, Xiaoxing; Yu, Lei; Gui, Yingang; Hu, Weihua

    2016-03-01

    We theoretically investigated the decomposed gaseous components of sulfur hexafluoride (SF6), namely, H2S, SO2, SOF2, and SO2F2, adsorbed on pristine and Au-embedded graphene based on the revised Perdew-Burke-Ernzerhof calculation, which empirically includes a dispersion correction (DFT-D) for van der Waals interaction with standard generalized gradient approximation. Pristine graphene exhibits weak adsorption and absence of charge transfer, which indicates barely satisfactory sensing for decomposed components. The Au atom introduces magnetism to the pristine graphene after metal-embedded decoration as well as enhances conductivity. All four molecules induce certain hybridization between the molecules and Au-graphene, which results in chemical interactions. SOF2 and SO2F2 exhibit a strong chemisorption interaction with Au-graphene, while H2S and SO2 exhibit quasi-molecular binding effects. Only H2S exhibits n-type doping to Au-graphene, whereas the rest gases exhibit p-type doping. Magnetic moments fluctuate substantially in the original Au-graphene when H2S and SO2 are adsorbed. While the adsorption effects of SOF2 and SO2F2 generate magnetism quenching. The charge transfer mechanism is also discussed in this paper. These results will shed light on the valuable application of Au-embedded graphene for selective gas sensing and spintronics.

  14. Toenails as an alternative source material for the extraction of DNA from decomposed human remains.

    Science.gov (United States)

    Schlenker, Andrew; Grimble, Katelyn; Azim, Arani; Owen, Rebecca; Hartman, Dadna

    2016-01-01

    The DNA identification of decomposed human remains for coronial investigations at the Victorian Institute of Forensic Medicine routinely requires the retrieval and processing of a bone sample obtained from the deceased. Bone is a difficult sample type to work with as it requires surgical removal from the deceased, refrigerated storage, and additional processing steps prior to DNA analysis in comparison to other samples types such as buccal swabs or blood stains. In an attempt to overcome the issues posed by bone, a DNA extraction method utilising toenails as an alternate source material was optimised and trialled. Two DNA extraction methods were optimised for digestion of toenail material, with the method utilising the QIAGEN DNA Investigator Kit selected for a casework trial. Single source DNA profiles, matching those of the conventional samples taken, were obtained for toenail samples collected from 28 of 30 coronial cases available for this study. Of these, 26 toenail samples produced full profiles. Although the overall DNA profile quality from the toenails was less than that of the conventional sample, the profiles from toenails met the reporting requirements for identification. Based on the results obtained, the Victorian Institute of Forensic Medicine will be implementing toenails as the primary sample type for collection from decomposed remains when blood is not a suitable sample type. Crown Copyright © 2015. Published by Elsevier Ireland Ltd. All rights reserved.

  15. Decomposed fuzzy systems and their application in direct adaptive fuzzy control.

    Science.gov (United States)

    Hsueh, Yao-Chu; Su, Shun-Feng; Chen, Ming-Chang

    2014-10-01

    In this paper, a novel fuzzy structure termed as the decomposed fuzzy system (DFS) is proposed to act as the fuzzy approximator for adaptive fuzzy control systems. The proposed structure is to decompose each fuzzy variable into layers of fuzzy systems, and each layer is to characterize one traditional fuzzy set. Similar to forming fuzzy rules in traditional fuzzy systems, layers from different variables form the so-called component fuzzy systems. DFS is proposed to provide more adjustable parameters to facilitate possible adaptation in fuzzy rules, but without introducing a learning burden. It is because those component fuzzy systems are independent so that it can facilitate minimum distribution learning effects among component fuzzy systems. It can be seen from our experiments that even when the rule number increases, the learning time in terms of cycles is still almost constant. It can also be found that the function approximation capability and learning efficiency of the DFS are much better than that of the traditional fuzzy systems when employed in adaptive fuzzy control systems. Besides, in order to further reduce the computational burden, a simplified DFS is proposed in this paper to satisfy possible real time constraints required in many applications. From our simulation results, it can be seen that the simplified DFS can perform fairly with a more concise decomposition structure.

  16. Priming in the microbial landscape: periphytic algal stimulation of litter-associated microbial decomposers.

    Science.gov (United States)

    Kuehn, Kevin A; Francoeur, Steven N; Findlay, Robert H; Neely, Robert K

    2014-03-01

    Microbial communities associated with submerged detritus in aquatic ecosystems often comprise a diverse mixture of autotrophic and heterotrophic microbes, including algae, bacteria, protozoa, and fungi. Recent studies have documented increased rates of plant litter mass loss when periphytic algae are present. We conducted laboratory and field experiments to assess potential metabolic interactions between natural autotrophic and heterotrophic microbial communities inhabiting submerged decaying plant litter of Typha angustifolia and Schoenoplectus acutus. In the field, submerged plant litter was either exposed to natural sunlight or placed under experimental canopies that manipulated light availability and growth of periphytic algae. Litter was collected and returned to the laboratory, where algal photosynthesis was manipulated (light/dark incubation), while rates of bacterial and fungal growth and productivity were simultaneously quantified. Bacteria and fungi were rapidly stimulated by exposure to light, thus establishing the potential for algal priming of microbial heterotrophic decay activities. Experimental incubations of decaying litter with 14C- and 13C-bicarbonate established that inorganic C fixed by algal photosynthesis was rapidly transferred to and assimilated by heterotrophic microbial decomposers. Periphytic algal stimulation of microbial heterotrophs, especially fungal decomposers, is an important and largely unrecognized interaction within the detrital microbial landscape, which may transform our current conceptual understanding of microbial secondary production and organic matter decomposition in aquatic ecosystems.

  17. A timescale decomposed threshold regression downscaling approach to forecasting South China early summer rainfall

    Science.gov (United States)

    Song, Linye; Duan, Wansuo; Li, Yun; Mao, Jiangyu

    2016-09-01

    A timescale decomposed threshold regression (TSDTR) downscaling approach to forecasting South China early summer rainfall (SCESR) is described by using long-term observed station rainfall data and NOAA ERSST data. It makes use of two distinct regression downscaling models corresponding to the interannual and interdecadal rainfall variability of SCESR. The two models are developed based on the partial least squares (PLS) regression technique, linking SCESR to SST modes in preceding months on both interannual and interdecadal timescales. Specifically, using the datasets in the calibration period 1915-84, the variability of SCESR and SST are decomposed into interannual and interdecadal components. On the interannual timescale, a threshold PLS regression model is fitted to interannual components of SCESR and March SST patterns by taking account of the modulation of negative and positive phases of the Pacific Decadal Oscillation (PDO). On the interdecadal timescale, a standard PLS regression model is fitted to the relationship between SCESR and preceding November SST patterns. The total rainfall prediction is obtained by the sum of the outputs from both the interannual and interdecadal models. Results show that the TSDTR downscaling approach achieves reasonable skill in predicting the observed rainfall in the validation period 1985-2006, compared to other simpler approaches. This study suggests that the TSDTR approach, considering different interannual SCESR-SST relationships under the modulation of PDO phases, as well as the interdecadal variability of SCESR associated with SST patterns, may provide a new perspective to improve climate predictions.

  18. Studies on the interactions of bisphenols with anionic phospholipids of decomposer membranes in model systems.

    Science.gov (United States)

    Broniatowski, Marcin; Sobolewska, Katarzyna; Flasiński, Michał; Wydro, Paweł

    2016-04-01

    Bisphenol A (BPA) and other bisphenols constitute a class of organic pollutants, which because of their estrogenic properties, low dose activity and bioaccumulation pose considerable risk for public health as well as for the environment. Accumulated in the sediment bisphenols can endanger the decomposers' populations being incorporated into their cellular membranes; however, the mechanism of their membrane activity is unknown. Therefore, to study these phenomena we applied anionic phospholipid Langmuir monolayers as simple but versatile models of decomposers biomembranes. Phosphatidylglycerols and cardiolipins are not only the main components of bacterial membranes but also of crucial importance in mitochondrial and thylakoid membranes in eukaryotic cells. In our investigations we applied five compounds of the bisphenol class most commonly detected in the environment. To characterize the bisphenols-model membrane interactions we applied multiple mutually independent methods of physical chemistry; namely: the Langmuir monolayer technique, surface potential measurements, Brewster angle microscopy for the visualization of the monolayers' texture and grazing incidence X-ray diffraction for the discussion of the phospholipids packing within the monolayers. Our studies indicated that all the investigated bisphenols interact with the model membrane, but the strength of the interactions is dependent on the bisphenol structure and hydrophobicity and the fluidity of the model membranes. We proved that bisphenol S often treated as the least toxic BPA analog can also be incorporated to the model membranes changing their structure and fluidity.

  19. Gauge-invariant dynamical quantities of QED with decomposed gauge potentials

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Baohua [Institute of Theoretical Physics, Beijing University of Technology, Beijing 100124 (China); Huang Yongchang [Institute of Theoretical Physics, Beijing University of Technology, Beijing 100124 (China); Kavli Institute for Theoretical Physics China, CAS, Beijing 100080 (China); CCAST (World Lab.), P.O. Box 8730, Beijing 100080 (China)

    2011-09-15

    We discover an inner structure of the QED system; i.e., by decomposing the gauge potential into two orthogonal components, we obtain a new expansion of the Lagrangian for the electron-photon system, from which, we realize the orthogonal decomposition of the canonical momentum conjugate to the gauge potential with the canonical momentum's two components conjugate to the gauge potential's two components, respectively. Using the new expansion of Lagrangian and by the general method of field theory, we naturally derive the gauge invariant separation of the angular momentum of the electron-photon system from Noether theorem, which is the rational one and has the simplest form in mathematics, compared with the other four versions of the angular momentum separation available in literature. We show that it is only the longitudinal component of the gauge potential that is contained in the orbital angular momentum of the electron, as Chen et al. have said. A similar gauge invariant separation of the momentum is given. The decomposed canonical Hamiltonian is derived, from which we construct the gauge invariant energy operator of the electron moving in the external field generated by a proton [Phys. Rev. A 82, 012107 (2010)], where we show that the form of the kinetic energy containing the longitudinal part of the gauge potential is due to the intrinsic requirement of the gauge invariance. Our method provides a new perspective to look on the nucleon spin crisis and indicates that this problem can be solved strictly and systematically.

  20. Shared processing of perception and imagery of music in decomposed EEG.

    Science.gov (United States)

    Schaefer, Rebecca S; Desain, Peter; Farquhar, Jason

    2013-04-15

    The current work investigates the brain activation shared between perception and imagery of music as measured with electroencephalography (EEG). Meta-analyses of four separate EEG experiments are presented, each focusing on perception and imagination of musical sound, with differing levels of stimulus complexity. Imagination and perception of simple accented metronome trains, as manifested in the clock illusion, as well as monophonic melodies are discussed, as well as more complex rhythmic patterns and ecologically natural music stimuli. By decomposing the data with principal component analysis (PCA), similar component distributions are found to explain most of the variance in each experiment. All data sets show a fronto-central and a more central component as the largest sources of variance, fitting with projections seen for the network of areas contributing to the N1/P2 complex. We expanded on these results using tensor decomposition. This allows us to add in the tasks to find shared activation, but does not make assumptions of independence or orthogonality and calculates the relative strengths of these components for each task. The components found in the PCA were shown to be further decomposable into parts that load primarily on to the perception or imagery task, or both, thereby adding more detail. It is shown that the frontal and central components have multiple parts that are differentially active during perception and imagination. A number of possible interpretations of these results are discussed, taking into account the different stimulus materials and measurement conditions. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Chemical composition of decomposing stumps in successive rotation of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations

    Institute of Scientific and Technical Information of China (English)

    HUANG Zhiqun; XU Zhihong; BOYD Sue; WILLIAMS David

    2005-01-01

    Decomposition of stumps in successive rotation of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations was studied using a chronosequence approach. The results showed that decomposition rate constant of Chinese fir stump was 0.02695 as calculated from Olson's model. The N content of stump increased during the first two-year decomposition. When the dead stump C/N ratio was 463.2 ± 27.3, the stumps started to release N. The pattern of P release was similar to that for N. However, K content of stumps showed a consistent declining trend over time during the whole decomposition. 13C nuclear magnetic resonance spectroscopy with cross polarization and magic-angle spinning (13C CPMAS-NMR) was used to analyse organic carbon (C) components in decomposing stumps. The 13C CPMAS-NMR spectra of stumps displayed that stump was dominated by cellulose and hemicellulose. The spectra also showed the accumulation of intensity in alkyl C, aromatic C, and carboxyl C spectral regions, which was expected as the labile cellulose and hemicellulose components in O-alkyl C spectral region were selectively decomposed first.

  2. Mycorrhiza-mediated competition between plants and decomposers drives soil carbon storage.

    Science.gov (United States)

    Averill, Colin; Turner, Benjamin L; Finzi, Adrien C

    2014-01-23

    Soil contains more carbon than the atmosphere and vegetation combined. Understanding the mechanisms controlling the accumulation and stability of soil carbon is critical to predicting the Earth's future climate. Recent studies suggest that decomposition of soil organic matter is often limited by nitrogen availability to microbes and that plants, via their fungal symbionts, compete directly with free-living decomposers for nitrogen. Ectomycorrhizal and ericoid mycorrhizal (EEM) fungi produce nitrogen-degrading enzymes, allowing them greater access to organic nitrogen sources than arbuscular mycorrhizal (AM) fungi. This leads to the theoretical prediction that soil carbon storage is greater in ecosystems dominated by EEM fungi than in those dominated by AM fungi. Using global data sets, we show that soil in ecosystems dominated by EEM-associated plants contains 70% more carbon per unit nitrogen than soil in ecosystems dominated by AM-associated plants. The effect of mycorrhizal type on soil carbon is independent of, and of far larger consequence than, the effects of net primary production, temperature, precipitation and soil clay content. Hence the effect of mycorrhizal type on soil carbon content holds at the global scale. This finding links the functional traits of mycorrhizal fungi to carbon storage at ecosystem-to-global scales, suggesting that plant-decomposer competition for nutrients exerts a fundamental control over the terrestrial carbon cycle.

  3. Highly Polarized Electrons from GaAs-GaAsP and InGaAs-AlGaAs Strained Layer Superlattice Photocathodes

    CERN Document Server

    Nakanishi, T; Kuwahara, M; Naniwa, K; Nishitani, T; Okumi, S; Yamamoto, N; Yasui, K

    2004-01-01

    GaAs-GaAsP strained layer superlattice photocathode has been developed for highly polarized electron beams. This cathode achieved a maximum polarization of 92% with a quantum efficiency of 0.5%. Criteria for achieving the highest polarization together with high quantum efficiency using superlattice photocathodes are discussed based on experimental spin-resolved quantum efficiency spectra of GaAs-AlGaAs, InGaAs-AlGaAs and GaAs-GaAsP superlattice structures.

  4. GaN CVD Reactions: Hydrogen and Ammonia Decomposition and the Desorption of Gallium

    Energy Technology Data Exchange (ETDEWEB)

    Bartram, Michael E.; Creighton, J. Randall

    1999-05-26

    Isotopic labeling experiments have revealed correlations between hydrogen reactions, Ga desorption, and ammonia decomposition in GaN CVD. Low energy electron diffraction (LEED) and temperature programmed desorption (TPD) were used to demonstrate that hydrogen atoms are available on the surface for reaction after exposing GaN(0001) to deuterium at elevated temperatures. Hydrogen reactions also lowered the temperature for Ga desorption significantly. Ammonia did not decompose on the surface before hydrogen exposure. However, after hydrogen reactions altered the surface, N15H3 did undergo both reversible and irreversible decomposition. This also resulted in the desorption of N2 of mixed isotopes below the onset of GaN sublimation, This suggests that the driving force of the high nitrogen-nitrogen bond strength (226 kcal/mol) can lead to the removal of nitrogen from the substrate when the surface is nitrogen rich. Overall, these findings indicate that hydrogen can influence G-aN CVD significantly, being a common factor in the reactivity of the surface, the desorption of Ga, and the decomposition of ammonia.

  5. 2015 Lowndes County (GA) Lidar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — TASK NAME: NOAA OCM Lidar for Lowndes County, GA with the option to Collect Lidar in Cook and Tift Counties, GA Lidar Data Acquisition and Processing Production Task...

  6. FAST: FAST Analysis of Sequences Toolbox.

    Science.gov (United States)

    Lawrence, Travis J; Kauffman, Kyle T; Amrine, Katherine C H; Carper, Dana L; Lee, Raymond S; Becich, Peter J; Canales, Claudia J; Ardell, David H

    2015-01-01

    FAST (FAST Analysis of Sequences Toolbox) provides simple, powerful open source command-line tools to filter, transform, annotate and analyze biological sequence data. Modeled after the GNU (GNU's Not Unix) Textutils such as grep, cut, and tr, FAST tools such as fasgrep, fascut, and fastr make it easy to rapidly prototype expressive bioinformatic workflows in a compact and generic command vocabulary. Compact combinatorial encoding of data workflows with FAST commands can simplify the documentation and reproducibility of bioinformatic protocols, supporting better transparency in biological data science. Interface self-consistency and conformity with conventions of GNU, Matlab, Perl, BioPerl, R, and GenBank help make FAST easy and rewarding to learn. FAST automates numerical, taxonomic, and text-based sorting, selection and transformation of sequence records and alignment sites based on content, index ranges, descriptive tags, annotated features, and in-line calculated analytics, including composition and codon usage. Automated content- and feature-based extraction of sites and support for molecular population genetic statistics make FAST useful for molecular evolutionary analysis. FAST is portable, easy to install and secure thanks to the relative maturity of its Perl and BioPerl foundations, with stable releases posted to CPAN. Development as well as a publicly accessible Cookbook and Wiki are available on the FAST GitHub repository at https://github.com/tlawrence3/FAST. The default data exchange format in FAST is Multi-FastA (specifically, a restriction of BioPerl FastA format). Sanger and Illumina 1.8+ FastQ formatted files are also supported. FAST makes it easier for non-programmer biologists to interactively investigate and control biological data at the speed of thought.

  7. FAST: FAST Analysis of Sequences Toolbox

    Directory of Open Access Journals (Sweden)

    Travis J. Lawrence

    2015-05-01

    Full Text Available FAST (FAST Analysis of Sequences Toolbox provides simple, powerful open source command-line tools to filter, transform, annotate and analyze biological sequence data. Modeled after the GNU (GNU’s Not Unix Textutils such as grep, cut, and tr, FAST tools such as fasgrep, fascut, and fastr make it easy to rapidly prototype expressive bioinformatic workflows in a compact and generic command vocabulary. Compact combinatorial encoding of data workflows with FAST commands can simplify the documentation and reproducibility of bioinformatic protocols, supporting better transparency in biological data science. Interface self-consistency and conformity with conventions of GNU, Matlab, Perl, BioPerl, R and GenBank help make FAST easy and rewarding to learn. FAST automates numerical, taxonomic, and text-based sorting, selection and transformation of sequence records and alignment sites based on content, index ranges, descriptive tags, annotated features, and in-line calculated analytics, including composition and codon usage. Automated content- and feature-based extraction of sites and support for molecular population genetic statistics makes FAST useful for molecular evolutionary analysis. FAST is portable, easy to install and secure thanks to the relative maturity of its Perl and BioPerl foundations, with stable releases posted to CPAN. Development as well as a publicly accessible Cookbook and Wiki are available on the FAST GitHub repository at https://github.com/tlawrence3/FAST. The default data exchange format in FAST is Multi-FastA (specifically, a restriction of BioPerl FastA format. Sanger and Illumina 1.8+ FastQ formatted files are also supported. FAST makes it easier for non-programmer biologists to interactively investigate and control biological data at the speed of thought.

  8. Double decomposition: decomposing the variance in subcomponents of male extra-pair reproductive success.

    Science.gov (United States)

    Losdat, Sylvain; Arcese, Peter; Reid, Jane M

    2015-09-01

    1. Extra-pair reproductive success (EPRS) is a key component of male fitness in socially monogamous systems and could cause selection on female extra-pair reproduction if extra-pair offspring (EPO) inherit high value for EPRS from their successful extra-pair fathers. However, EPRS is itself a composite trait that can be fully decomposed into subcomponents of variation, each of which can be further decomposed into genetic and environmental variances. However, such decompositions have not been implemented in wild populations, impeding evolutionary inference. 2. We first show that EPRS can be decomposed into the product of three life-history subcomponents: the number of broods available to a focal male to sire EPO, the male's probability of siring an EPO in an available brood and the number of offspring in available broods. This decomposition of EPRS facilitates estimation from field data because all subcomponents can be quantified from paternity data without need to quantify extra-pair matings. Our decomposition also highlights that the number of available broods, and hence population structure and demography, might contribute substantially to variance in male EPRS and fitness. 3. We then used 20 years of complete genetic paternity and pedigree data from wild song sparrows (Melospiza melodia) to partition variance in each of the three subcomponents of EPRS, and thereby estimate their additive genetic variance and heritability conditioned on effects of male coefficient of inbreeding, age and social status. 4. All three subcomponents of EPRS showed some degree of within-male repeatability, reflecting combined permanent environmental and genetic effects. Number of available broods and offspring per brood showed low additive genetic variances. The estimated additive genetic variance in extra-pair siring probability was larger, although the 95% credible interval still converged towards zero. Siring probability also showed inbreeding depression and increased with male age

  9. Are Bulges and Disks Real? Decomposing Spectral Data Cubes Into Their Astrophysical Components

    Science.gov (United States)

    Merrifield, Michael; Tabor, Martha; Aragon-Salamanca, Alfonso; Cappellari, Michele; Johnston, Evelyn

    2016-01-01

    Decomposing galaxies photometrically into bulge and disk components is now a well-established technique, but it remains unclear how distinct and real these components are, and how they relate to each other. To address these questions, we have been developing novel techniques to extract the various structural components from integral field unit (IFU) spectral observations of galaxies, in order to study simultaneously their spectral and spatial properties.As a first approach, by spatially decomposing each wavelength in a spectral data cube, we can discover how much light comes from the separate components as a function of wavelength, and hence derive unprecedentedly high quality spectra of bulge and disk for detailed analysis of their stellar populations.In addition, we have decomposed spectral data cubes by fitting the spectrum at each location with the sum of two components, with the spectral properties left entirely free to fit both kinematic and stellar population properties, subject only to the constraint that the relative flux contributions match those of a conventional bulge-disk decomposition.Initial results applied to MaNGA and other IFU surveys show the power of these techniques when applied to such high quality data. The first method allows us to understand the formation sequence of bulges and disks, with, for example, bulges showing the younger stellar populations in S0 galaxies, implying that this was where the last gasp of star formation occurred. The second technique reveals subtle population gradients within individual components, but also confirms that the decomposition into separate components is a credible procedure, as the resulting bulges and disks have entirely plausible kinematic properties that are in no way imposed by the decomposition.Although our initial application of these decomposition techniques has been to studying bulges and disks in S0 galaxies, the methods have much wider application to the spectral data cubes that MaNGA and other

  10. Functional breadth and home-field advantage generate functional differences among soil microbial decomposers.

    Science.gov (United States)

    Fanin, Nicolas; Fromin, Nathalie; Bertrand, Isabelle

    2016-04-01

    In addition to the effect of litter quality (LQ) on decomposition, increasing evidence is demonstrating that carbon mineralization can be influenced by the past resource history, mainly through following two processes: (1) decomposer communities from recalcitrant litter environments may have a wider functional ability to decompose a wide range of litter species than those originating from richer environments, i.e., the functional breadth (FB) hypothesis; and/or (2) decomposer communities may be specialized towards the litter they most frequently encounter, i.e., the home-field advantage (HFA) hypothesis. Nevertheless, the functional dissimilarities among contrasting microbial communities, which are generated by the FB and the HFA, have rarely been simultaneously quantified in the same experiment, and their relative contributions over time have never been assessed. To test these hypotheses, we conducted a reciprocal transplant decomposition experiment under controlled conditions using litter and soil originating from four ecosystems along a land-use gradient (forest, plantation, grassland, and cropland) and one additional treatment using 13C-labelled flax litter allowing us to assess the priming effect (PE) in each ecosystem. We found substantial effects of LQ on carbon mineralization (more than two-thirds of the explained variance), whereas the contribution of the soil type was fairly low (less than one-tenth), suggesting that the contrasting soil microbial communities play only a minor role in regulating decomposition rates. Although the results on PE showed that we overestimated litter-derived CO2 fluxes, litter-microbe interactions contributed significantly to the unexplained variance observed in carbon mineralization models. The magnitudes of FB and HFA were relatively similar, but the directions of these mechanisms were sometimes opposite depending on the litter and soil types. FB and HFA estimates calculated on parietal sugar mass loss were positively

  11. Impact of decomposing Cinnamomum septentrionale leaf litter on the growth of Eucalyptus grandis saplings.

    Science.gov (United States)

    Huang, Weiwei; Hu, Tingxing; Chen, Hong; Wang, Qian; Hu, Hongling; Tu, Lihua; Jing, Liao

    2013-09-01

    A pot experiment was performed to study the impact of decomposing Cinnamomum septentrionale leaf litter on the growth of Eucalyptus grandis saplings. The experimental design scheme was 0 (CK), 40 (A1), 80 (A2) and 120 g pot(-1) (A3) of E. grandis leaves, and changes in the volatile oil chemical composition during litter decomposition were assessed in the present study. The results showed that C. septentrionale leaf litter inhibited the growth of E. grandis saplings, as determined by the height, basal diameter and chlorophyll content, after 69 d (T1). Five months after transplantation (T2), the height growth rate of the E. grandis saplings increased and then gradually reduced (A1: 40 g pot(-1) > A2: 80 g pot(-1) > A3: 120 g pot(-1) > CK: 0 g pot(-1)). After eleven months (T3), the variations in the height and basal diameter were the same as observed at T2, and the inhibition on leaf, branch, root and stem biomass increased with increasing leaf litter content. Gas chromatography-mass spectrometry (GC-MS) was used to identify the volatile compound composition. The results indicated that the C. septentrionale original leaf litter (S1) contained thirty-one volatile compounds, but the treated leaf litter S2 (which was mixed with soil for eleven months to simultaneously plant E. grandis saplings) only possessed fourteen volatile compounds, releasing many secondary metabolites in the soil during decomposition. Most of the volatile compounds were alcohols, monoterpenoids, sesquiterpenes, alkanes, alkene, esters and ketones. Most of the allelochemicals of C. septentrionale might be released during the initial decomposing process, inhibiting the growth of other plants, whereas some nutrients might be released later, promoting the height growth of plants. In conclusion, decomposing C. septentrionale leaf litter release of many allelochemicals in the soil that significantly inhibit the growth of E. grandis.

  12. Coulomb excitation of Ga-73

    NARCIS (Netherlands)

    Diriken, J.; Stefanescu, I.; Balabanski, D.; Blasi, N.; Blazhev, A.; Bree, N.; Cederkaell, J.; Cocolios, T. E.; Davinson, T.; Eberth, J.; Ekstrom, A.; Fedorov, D. V.; Fedosseev, V. N.; Fraile, L. M.; Franchoo, S.; Georgiev, G.; Gladnishki, K.; Huyse, M.; Ivanov, O. V.; Ivanov, V. S.; Iwanicki, J.; Jolie, J.; Konstantinopoulos, T.; Kroell, Th.; Kruecken, R.; Koester, U.; Lagoyannis, A.; Lo Bianco, G.; Maierbeck, P.; Marsh, B. A.; Napiorkowski, P.; Patronis, N.; Pauwels, D.; Reiter, P.; Seliverstov, M.; Sletten, G.; Van de Walle, J.; Van Duppen, P.; Voulot, D.; Walters, W. B.; Warr, N.; Wenander, F.; Wrzosek, K.

    2010-01-01

    The B(E2; I-i -> I-f) values for transitions in Ga-71(31)40 and Ga-73(31)42 were deduced from a Coulomb excitation experiment at the safe energy of 2.95 MeV/nucleon using post-accelerated beams of Ga-71,Ga-73 at the REX-ISOLDE on-line isotope mass separator facility. The emitted gamma rays were dete

  13. Fast approximate convex decomposition using relative concavity

    KAUST Repository

    Ghosh, Mukulika

    2013-02-01

    Approximate convex decomposition (ACD) is a technique that partitions an input object into approximately convex components. Decomposition into approximately convex pieces is both more efficient to compute than exact convex decomposition and can also generate a more manageable number of components. It can be used as a basis of divide-and-conquer algorithms for applications such as collision detection, skeleton extraction and mesh generation. In this paper, we propose a new method called Fast Approximate Convex Decomposition (FACD) that improves the quality of the decomposition and reduces the cost of computing it for both 2D and 3D models. In particular, we propose a new strategy for evaluating potential cuts that aims to reduce the relative concavity, rather than absolute concavity. As shown in our results, this leads to more natural and smaller decompositions that include components for small but important features such as toes or fingers while not decomposing larger components, such as the torso, that may have concavities due to surface texture. Second, instead of decomposing a component into two pieces at each step, as in the original ACD, we propose a new strategy that uses a dynamic programming approach to select a set of n c non-crossing (independent) cuts that can be simultaneously applied to decompose the component into n c+1 components. This reduces the depth of recursion and, together with a more efficient method for computing the concavity measure, leads to significant gains in efficiency. We provide comparative results for 2D and 3D models illustrating the improvements obtained by FACD over ACD and we compare with the segmentation methods in the Princeton Shape Benchmark by Chen et al. (2009) [31]. © 2012 Elsevier Ltd. All rights reserved.

  14. Long-term stabilization of organic solar cells using hydroperoxide decomposers as additives

    Science.gov (United States)

    Turkovic, Vida; Engmann, Sebastian; Tsierkezos, Nikos; Hoppe, Harald; Madsen, Morten; Rubahn, Horst-Günter; Ritter, Uwe; Gobsch, Gerhard

    2016-03-01

    Stability of organic solar cells (OPV) remains a big problem on the way to their commercialization. Different approaches are being investigated: development of intrinsically more photochemically stable materials, optimization of encapsulation, and implementation of getter and UV blocking layers. In this study, we investigate stabilization of OPV devices using hydroperoxide decomposers as stabilizing additives. A set of five commercially available additives of organophosphorus, organosulfur, Ni chelate, and blocked thiol type are compared, ternary blended into the active layer, under exposure to aging under ISOS-3 degradation conditions. Improvements in long-term performance of OPV devices were observed upon stabilization with Advapak NEO-1120, lifetime was prolonged by a factor of 1.7, and accumulated power generation increased by a factor of 1.4. The stabilizing mechanisms are discussed using spectroscopic and microscopic measurements.

  15. Experimentally simulated global warming and nitrogen enrichment effects on microbial litter decomposers in a marsh

    DEFF Research Database (Denmark)

    Flury, Sabine; Gessner, Mark

    2011-01-01

    obtained by denaturing gradient gel electrophoresis (DGGE) indicated that simulated global warming induced a shift in bacterial community structure. In addition, warming reduced fungal biomass, whereas bacterial biomass was unaffected. The mesh size of the litter bags and sampling date also had......Atmospheric warming and increased nitrogen deposition can lead to changes of microbial communities with possible consequences for biogeochemical processes. We used an enclosure facility in a freshwater marsh to assess the effects on microbes associated with decomposing plant litter under conditions...... of simulated climate warming and pulsed nitrogen supply. Standard batches of litter were placed in coarse-mesh and fine-mesh bags and submerged in a series of heated, nitrogen-enriched, and control enclosures. They were retrieved later and analyzed for a range of microbial parameters. Fingerprinting profiles...

  16. Decomposing race and gender differences in underweight and obesity in South Africa.

    Science.gov (United States)

    Averett, Susan L; Stacey, Nicholas; Wang, Yang

    2014-12-01

    Using data from the National Income Dynamics Study, we document differentials in both underweight and obesity across race and gender in post-Apartheid South Africa. Using a nonlinear decomposition method, we decompose these differences across gender within race and then across race within gender. Less than one third of the differences in obesity and underweight across gender are explained by differences in covariates. In contrast, at least 70% of the obesity differences across race are explained by differences in covariates. Behavioral variables such as smoking and exercise explain the largest part of the bodyweight differentials across gender. For bodyweight differentials across race within gender, however, socioeconomic status and background variables have the largest explanatory power for obesity differentials, while background variables play the key role in explaining the underweight differentials. These results indicate that eradicating obesity and underweight differentials will require targeting policies to specific groups.

  17. The plant cell wall decomposing machinery underlies the functional diversity of forest fungi

    Energy Technology Data Exchange (ETDEWEB)

    Eastwood, Daniel C.; Floudas, Dimitrios; Binder, Manfred; Majcherczyk, Andrzej; Schneider, Patrick; Aerts, Andrea; Asiegbu, Fred O.; Baker, Scott E.; Barry, Kerrie; Bendiksby, Mika; Blumentritt, Melanie; Coutinho, Pedro M.; Cullen, Dan; Vries, Ronald P. de; Gathman, Allen; Goodell, Barry; Henrissat, Bernard; Ihrmark, Katarina; Kauserud, Hä; vard,; Kohler, Annegret; LaButti, Kurt; Lapidus, Alla; Lavin, José; L.; Lee, Yong-Hwan; Lindquist, Erika; Lilly, Walt; Lucas, Susan; Morin, Emmanuelle; Murat, Claude; Oguiza, José; A.; Park, Jongsun; Pisabarro, Antonio G.; Riley, Robert; Rosling, Anna; Salamov, Asaf; Schmidt, Olaf; Schmutz, Jeremy; Skrede, Inger; Stenlid, Jan; Wiebenga, Ad; Xie, Xinfeng; Kü; es, Ursula; Hibbett, David S.; Hoffmeister, Dirk; Hö; gberg, Nils; Martin, Francis; Grigoriev, Igor V.; Watkinson, Sarah C.

    2011-05-01

    Brown rot decay removes cellulose and hemicellulose from wood?residual lignin contributing up to 30percent of forest soil carbon?and is derived from an ancestral white rot saprotrophy in which both lignin and cellulose are decomposed. Comparative and functional genomics of the ?dry rot? fungus Serpula lacrymans, derived from forest ancestors, demonstrated that the evolution of both ectomycorrhizal biotrophy and brown rot saprotrophy were accompanied by reductions and losses in specific protein families, suggesting adaptation to an intercellular interaction with plant tissue. Transcriptome and proteome analysis also identified differences in wood decomposition in S. lacrymans relative to the brown rot Postia placenta. Furthermore, fungal nutritional mode diversification suggests that the boreal forest biome originated via genetic coevolution of above- and below-ground biota

  18. Synthesis of Graphene-Based Sensors and Application on Detecting SF6 Decomposing Products: A Review.

    Science.gov (United States)

    Zhang, Xiaoxing; Cui, Hao; Gui, Yingang

    2017-02-13

    Graphene-based materials have aroused enormous focus on a wide range of engineering fields because of their unique structure. One of the most promising applications is gas adsorption and sensing. In electrical engineering, graphene-based sensors are also employed as detecting devices to estimate the operation status of gas insulated switchgear (GIS). This paper reviews the main synthesis methods of graphene, gas adsorption, and sensing mechanism of its based sensors, as well as their applications in detecting SF6 decomposing products, such as SO2, H2S, SO2F2, and SOF2, in GIS. Both theoretical and experimental researches on gas response of graphene-based sensors to these typical gases are summarized. Finally, the future research trend about graphene synthesis technique and relevant perspective are also given.

  19. Bacteria in decomposing wood and their interactions with wood-decay fungi.

    Science.gov (United States)

    Johnston, Sarah R; Boddy, Lynne; Weightman, Andrew J

    2016-11-01

    The fungal community within dead wood has received considerable study, but far less attention has been paid to bacteria in the same habitat. Bacteria have long been known to inhabit decomposing wood, but much remains underexplored about their identity and ecology. Bacteria within the dead wood environment must interact with wood-decay fungi, but again, very little is known about the form this takes; there are indications of both antagonistic and beneficial interactions within this fungal microbiome. Fungi are hypothesised to play an important role in shaping bacterial communities in wood, and conversely, bacteria may affect wood-decay fungi in a variety of ways. This minireview considers what is currently known about bacteria in wood and their interactions with fungi, and proposes possible associations based on examples from other habitats. It aims to identify key knowledge gaps and pressing questions for future research. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Synthesis of Graphene-Based Sensors and Application on Detecting SF6 Decomposing Products: A Review

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2017-02-01

    Full Text Available Graphene-based materials have aroused enormous focus on a wide range of engineering fields because of their unique structure. One of the most promising applications is gas adsorption and sensing. In electrical engineering, graphene-based sensors are also employed as detecting devices to estimate the operation status of gas insulated switchgear (GIS. This paper reviews the main synthesis methods of graphene, gas adsorption, and sensing mechanism of its based sensors, as well as their applications in detecting SF6 decomposing products, such as SO2, H2S, SO2F2, and SOF2, in GIS. Both theoretical and experimental researches on gas response of graphene-based sensors to these typical gases are summarized. Finally, the future research trend about graphene synthesis technique and relevant perspective are also given.

  1. Decomposing biodiversity data using the Latent Dirichlet Allocation model, a probabilistic multivariate statistical method.

    Science.gov (United States)

    Valle, Denis; Baiser, Benjamin; Woodall, Christopher W; Chazdon, Robin

    2014-12-01

    We propose a novel multivariate method to analyse biodiversity data based on the Latent Dirichlet Allocation (LDA) model. LDA, a probabilistic model, reduces assemblages to sets of distinct component communities. It produces easily interpretable results, can represent abrupt and gradual changes in composition, accommodates missing data and allows for coherent estimates of uncertainty. We illustrate our method using tree data for the eastern United States and from a tropical successional chronosequence. The model is able to detect pervasive declines in the oak community in Minnesota and Indiana, potentially due to fire suppression, increased growing season precipitation and herbivory. The chronosequence analysis is able to delineate clear successional trends in species composition, while also revealing that site-specific factors significantly impact these successional trajectories. The proposed method provides a means to decompose and track the dynamics of species assemblages along temporal and spatial gradients, including effects of global change and forest disturbances.

  2. May Ingestion of Leachate from Decomposed Corpses Cause Appendicitis? A Case Report

    Directory of Open Access Journals (Sweden)

    Maurício Domingues-Ferreira

    2011-01-01

    Full Text Available The general consensus is that appendicitis is basically provoked by fecaliths or lymphoid hyperplasic obstruction. Several studies based on histological diagnosis have not confirmed this hypothesis. On the contrary, obstruction has been proved in only a minority of cases. Diverse infections by parasites, bacteria, fungus, and noninfective agents have been associated with appendicitis in the medical literature. We describe a firefighter, who ingested a small quantity of leachate from decomposing corpses while working and developed enteritis a few hours later, which lasted several days and evolved to appendicitis. This case raises the possibility that the high quantity of bacteria concentration present in the leachate could have provoked enteritis and the subsequent appendicitis due to a direct effect of the bacteria on the appendix.

  3. May Ingestion of Leachate from Decomposed Corpses Cause Appendicitis? A Case Report

    Science.gov (United States)

    Domingues-Ferreira, Maurício; Saddi-Rosa, Pedro; dos Santos, André Luis

    2011-01-01

    The general consensus is that appendicitis is basically provoked by fecaliths or lymphoid hyperplasic obstruction. Several studies based on histological diagnosis have not confirmed this hypothesis. On the contrary, obstruction has been proved in only a minority of cases. Diverse infections by parasites, bacteria, fungus, and noninfective agents have been associated with appendicitis in the medical literature. We describe a firefighter, who ingested a small quantity of leachate from decomposing corpses while working and developed enteritis a few hours later, which lasted several days and evolved to appendicitis. This case raises the possibility that the high quantity of bacteria concentration present in the leachate could have provoked enteritis and the subsequent appendicitis due to a direct effect of the bacteria on the appendix. PMID:21541232

  4. The plant cell wall-decomposing machinery underlies the functional diversity of forest fungi.

    Science.gov (United States)

    Eastwood, Daniel C; Floudas, Dimitrios; Binder, Manfred; Majcherczyk, Andrzej; Schneider, Patrick; Aerts, Andrea; Asiegbu, Fred O; Baker, Scott E; Barry, Kerrie; Bendiksby, Mika; Blumentritt, Melanie; Coutinho, Pedro M; Cullen, Dan; de Vries, Ronald P; Gathman, Allen; Goodell, Barry; Henrissat, Bernard; Ihrmark, Katarina; Kauserud, Hävard; Kohler, Annegret; LaButti, Kurt; Lapidus, Alla; Lavin, José L; Lee, Yong-Hwan; Lindquist, Erika; Lilly, Walt; Lucas, Susan; Morin, Emmanuelle; Murat, Claude; Oguiza, José A; Park, Jongsun; Pisabarro, Antonio G; Riley, Robert; Rosling, Anna; Salamov, Asaf; Schmidt, Olaf; Schmutz, Jeremy; Skrede, Inger; Stenlid, Jan; Wiebenga, Ad; Xie, Xinfeng; Kües, Ursula; Hibbett, David S; Hoffmeister, Dirk; Högberg, Nils; Martin, Francis; Grigoriev, Igor V; Watkinson, Sarah C

    2011-08-05

    Brown rot decay removes cellulose and hemicellulose from wood--residual lignin contributing up to 30% of forest soil carbon--and is derived from an ancestral white rot saprotrophy in which both lignin and cellulose are decomposed. Comparative and functional genomics of the "dry rot" fungus Serpula lacrymans, derived from forest ancestors, demonstrated that the evolution of both ectomycorrhizal biotrophy and brown rot saprotrophy were accompanied by reductions and losses in specific protein families, suggesting adaptation to an intercellular interaction with plant tissue. Transcriptome and proteome analysis also identified differences in wood decomposition in S. lacrymans relative to the brown rot Postia placenta. Furthermore, fungal nutritional mode diversification suggests that the boreal forest biome originated via genetic coevolution of above- and below-ground biota.

  5. 2+1 flavor lattice QCD with Luscher's Domain-Decomposed HMC algorithm

    Science.gov (United States)

    Kuramashi, Yoshinobu

    2006-12-01

    We report on a study of 2+1 flavor lattice QCD with the O(a)-improved Wilson quarks on a 163 × 32 lattice at the lattice spacing 1/a ≈ 2GeV employing Lüscher's domain-decomposed HMC(LDDHMC) algorithm. This is dedicated to a preliminary study for the PACS-CS project which plans to complete the Wilson-clover N f = 2 + 1 program lowering the up-down quark masses close to the physical values as much as possible. We focus on three issues: (i) how light quark masses we can reach with LDDHMC, (ii) efficiency of the algorithm compared with the conventional HMC, (iii) parameter choice for the production runs on PACS-CS.

  6. Influence of NaCl-CaCl2 on Decomposing REPO4 with CaO

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The influence of NaCl-CaCl2 on thermal decomposition of REPO4 (RE: Ce, La, Nd, Th) with CaO was studied.The heat decomposing process of REPO4 was tested with TG-DTA experiments.The results showed that the decomposition temperature of REPO4 with CaO was reduced because of adding NaCl-CaCl2 mixture (NaCl:CaCl2=1:1).The influence of the addition of NaCl-CaCl2, roasting temperature and roasting time on decomposition ratio of REPO4 with CaO was studied.The results showed that the decomposition ratio of REPO4with CaO was 79% when the addition percentage of NaCl-CaCl2 was 10%, the roasting temperature was 750℃, and the roasting time was 1 h.

  7. The applications of a higher-dimensional Lie algebra and its decomposed subalgebras.

    Science.gov (United States)

    Yu, Zhang; Zhang, Yufeng

    2009-01-15

    With the help of invertible linear transformations and the known Lie algebras, a higher-dimensional 6 x 6 matrix Lie algebra smu(6) is constructed. It follows a type of new loop algebra is presented. By using a (2 + 1)-dimensional partial-differential equation hierarchy we obtain the integrable coupling of the (2 + 1)-dimensional KN integrable hierarchy, then its corresponding Hamiltonian structure is worked out by employing the quadratic-form identity. Furthermore, a higher-dimensional Lie algebra denoted by E, is given by decomposing the Lie algebra smu(6), then a discrete lattice integrable coupling system is produced. A remarkable feature of the Lie algebras smu(6) and E is used to directly construct integrable couplings.

  8. Trend Prediction and Decomposed Driving Factors of Carbon Emissions in Jiangsu Province during 2015–2020

    Directory of Open Access Journals (Sweden)

    Decai Tang

    2016-10-01

    Full Text Available According to the economic and energy consumption statistics in Jiangsu Province, we combined the GM (1, 1 grey model and polynomial regression to forecast carbon emissions. Historical and projected emissions were decomposed using the Logarithmic Mean Divisia Index (LMDI approach to assess the relative contribution of different factors to emission variability. The results showed that carbon emissions will continue to increase in Jiangsu province during 2015–2020 period and cumulative carbon emissions will increase by 39.5487 million tons within the forecast period. The growth of gross domestic product (GDP per capita plays the greatest positive role in driving carbon emission growth. Furthermore, the improvement of energy usage efficiency is the primary factor responsible for reducing carbon emissions. Factors of population, industry structure adjustment and the optimization of fuel mix also help to reduce carbon emissions. Based on the LMDI analysis, we provide some advice for policy-makers in Jiangsu and other provinces in China.

  9. Measuring and decomposing output gap: A production function approach of the USA and EU-27 countries

    Directory of Open Access Journals (Sweden)

    Domicián Máté

    2012-11-01

    Full Text Available The ICT-based techno-economic paradigm shift was sharpened by income inequalities in all over the world. The economic performance of USA and Europe were seemed to more different thanks to global economic events. The main purpose of this study is to estimate various macroeconomic variables such as GDP and labour for the period of 1993-2013. In order to indicate economic growth an alternative growth accounting method was used to decompose impacts of physical capital accumulation, technological changes and labour. Analysing the time series data of various OECD countries we could conclude that a large part of the variations in the output gap stem from the cyclical variations of total labour input and the total factor productivity (TFP. Hence, our results were reflected the relevance of technological progress.

  10. Microwave-supported preparation of (68)Ga bioconjugates with high specific radioactivity.

    Science.gov (United States)

    Velikyan, I; Beyer, G J; Långström, B

    2004-01-01

    The generator-produced positron-emitting (68)Ga (T(1/2) = 68 min) is of potential interest for clinical PET. (68)Ga as a metallic cation is suitable for complexation reactions with chelators, naked or conjugated, with peptides or other macromolecules. Large (68)Ga generator eluate volumes, metal traces from the generator column material, or reaction reagents, however, disturb a fast, reliable, and quantitative labeling procedure. In this paper we describe a simple technique, based on anion exchange, aiming first, to increase the (68)Ga concentration, second to purify it from competing impurities, and third to obtain a fast and quantitative (68)Ga-labeled peptide conjugate that can be applied in humans without further purification. Within 5 min one can obtain from the original 6 mL generator eluate a 200 microL (68)Ga preparation (volume reduction by a factor 30) that is suitable for direct and quantitative labeling of peptide conjugates. DOTATOC (DOTA-D-Phe(1)-Tyr(3)-octreotide, DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) was used as a test tracer for comparing the labeling properties of the different (68)Ga preparations. In combination with microwave heating, peptide conjugates of 0.5-1 nmol quantities could be labeled within 10 min with the full (68)Ga activity of a generator. Further purification of the (68)Ga-labeled peptide conjugate was no longer required since the nuclide incorporation was quantitative. The specific radioactivity (with respect to the peptide) was improved by a factor approximately 100 compared to the previously applied techniques using the original generator eluate. The commercial (68)Ge/(68)Ga generator from Obninsk in combination with this system for purification and concentration with an integrated microwave-supported labeling technology resulted in a kitlike technology for (68)Ga-tracer production. The first automated prototype using this technology is being tested.

  11. Different degradation behaviors of InGaN/GaN MQWs blue and violet LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Huang Liubing [State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Yu Tongjun, E-mail: tongjun@pku.edu.c [State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Chen Zhizhong; Qin Zhixin; Yang Zhijian; Zhang Guoyi [State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)

    2009-12-15

    InGaN/GaN multiple quantum wells (MQWs) blue and violet light-emitting diodes (LEDs) were stressed under the injection current density of 26.5 A/cm{sup 2} for about 400 h at room temperature. Degradation behaviors of blue and violet LEDs were compared. Two stages of degradation were identified in the blue and violet LEDs. At the initial stage, the violet LEDs degraded very fast, but the blue LEDs degraded relatively slow. At later stage, both blue and violet LEDs showed similar degradation rates. Analyses of the L-I and I-V characteristics revealed that the increase of effective nonradiative recombination centers in the active regions was responsible for both blue and violet LED degradations. Rapid degradation of violet LEDs at early stage resulted from dramatical increase of the effective nonradiative centers. More indium in the MQWs might be helpful for better reliability performance of blue LEDs.

  12. Climatic effects on decomposing litter and substrate chemistry along climatological gradients.

    Science.gov (United States)

    Berg, B.

    2009-04-01

    Climatic effects on decomposing litter and substrate chemistry along climatological gradients. B. Berg, Dipartimento Biologia Strutturale e Funzionale, Complesso Universitario, Monte San Angelo, via Cintia, I-80126 Napoli, Italy and Department of Forest Ecology, P.O. Box 27, University of Helsinki, FIN-00014, Helsinki, Finland. Studies of several processes, using climatic gradients do provide new information as compared with studies at e.g. a single site. Decomposition of plant litter in such gradients give response in decomposition rates to natural climate conditions. Thus Scots pine needle litter incubated in a climate gradient with annual average temperature (AVGT) ranging from -0.5 to 6.8oC had a highly significant increase in initial mass-loss rate with R2 = 0.591 (p<0.001) and a 5o increase in temperature doubled the mass-loss rate. As a contrast - needle litter of Norway spruce incubated in the same transect had no significant response to climate and for initial litter a 5o increase increased mass-loss rate c. 6%. For more decomposed Scots pine litter we could see that the effect of temperature on mass-loss rate gradually decreased until it disappeared. Long-term decomposition studies revealed differences in litter decomposition patterns along a gradient, even for the same type of litter. This could be followed by using an asymptotic function that gave, (i) a measure a maximum level of decomposition, (ii) the initial decomposition rate. Over a gradient the calculated maximum level of decomposition decreased with increasing AVGT. Other gradient studies revealed an effect of AVGT on litter chemical composition. Pine needle litter from stands under different climate conditions had nutrient concentrations related to AVGT. Thus N, P, K, and S were positively related to AVGT and Mn negatively, all of them significantly. This information may be used to explain the changing pattern in decomposition over the gradient.

  13. Contrasting patterns of litterfall seasonality and seasonal changes in litter decomposability in a tropical rainforest region

    Directory of Open Access Journals (Sweden)

    S. A. Parsons

    2014-06-01

    Full Text Available The seasonality of litter inputs in forests has important implications for understanding ecosystem processes and biogeochemical cycles. We quantified the drivers of seasonality in litterfall and leaf decomposability, using plots throughout the Australian wet tropical region. Litter fell mostly in the summer (wet, warm months in the region, but other peaks occurred throughout the year. Litterfall seasonality was modelled well with the level of deciduousness of the site (plots with more deciduous species had lower seasonality than evergreen plots, temperature (higher seasonality in the uplands, disturbance (lower seasonality with more early secondary species and soil fertility (higher seasonality with higher N : P/P limitation (SL total litterfall model 1 = deciduousness + soil N : P + early secondary sp: r2 = 0.63, n = 30 plots; model 2 = temperature + early secondary sp. + soil N : P: r2 = 0.54, n = 30; SL leaf = temperature + early secondary sp. + rainfall seasonality: r2 = 0.39, n = 30. Leaf litter decomposability was lower in the dry season than in the wet season, driven by higher phenolic concentrations in the dry, with the difference exacerbated particularly by lower dry season moisture. Our results are contrary to the global trend for tropical rainforests; in that seasonality of litterfall inputs were generally higher in wetter, cooler, evergreen forests, compared to generally drier, warmer, semi-deciduous sites that had more uniform monthly inputs. We consider this due to more diverse litter shedding patterns in semi-deciduous and raingreen rainforest sites, and an important consideration for ecosystem modellers. Seasonal changes in litter quality are likely to have impacts on decomposition and biogeochemical cycles in these forests due to the litter that falls in the dry being more recalcitrant to decay.

  14. Antibiotics as a chemical stressor affecting an aquatic decomposer-detritivore system.

    Science.gov (United States)

    Bundschuh, Mirco; Hahn, Torsten; Gessner, Mark O; Schulz, Ralf

    2009-01-01

    Recent evidence indicates that a variety of antibiotic residues may affect the integrity of streams located downstream from wastewater treatment plants. Aquatic communities comprising bacterial and fungal decomposers and invertebrate detritivores (shredders) play an important role in the decomposition of allochthonous leaf litter, which acts as a primary energy source for small running waters. The aim of the present study was to assess whether an antibiotic mixture consisting of sulfamethoxazole, trimethoprim, erythromycin-H2O, roxithromycin, and clarithromycin has an effect on such a decomposer-detritivore system. Leaf discs were exposed to these antibiotics (total concentration of 2 or 200 microg/L) for approximately 20 d before offering these discs and corresponding control discs to an amphipod shredder, Gammarus fossarum, in a food choice experiment. Gammarus preferred the leaf discs conditioned in the presence of the antibiotic mixture at 200 microg/L over the control discs (pair-wise t test; p = 0.006). A similar tendency, while not significant, was observed for leaves conditioned with antibiotics at a concentration of 2 microg/L. The number of bacteria associated with leaves did not differ between treatments at either antibiotic concentration (t test; p = 0.57). In contrast, fungal biomass (measured as ergosterol) was significantly higher in the 200 microg/L treatment (t test; p = 0.038), suggesting that the preference of Gammarus may be related to a shift in fungal communities. Overall these results indicate that mixtures of antibiotics may disrupt important ecosystem processes such as organic matter flow in stream ecosystems, although effects are likely to be weak at antibiotic concentrations typical of streams receiving wastewater treatment plant effluents.

  15. Temperature response of soil respiration is dependent on concentration of readily decomposable C

    Directory of Open Access Journals (Sweden)

    A. A. Larionova

    2007-12-01

    Full Text Available Temperature acclimation of soil organic matter (SOM decomposition is one of the major uncertainties in predicting soil CO2 efflux associated with the increase in global mean temperature. A reasonable explanation for an apparent acclimation proposed by Davidson and colleagues (2006 based on Michaelis-Menten kinetics suggests that temperature sensitivity decreases when both maximal activity of respiratory enzymes (Vmax and half-saturation constant (Ks cancel each other upon temperature increase. We tested the hypothesis of the canceling effect by the mathematical simulation of data obtained in incubation experiments with forest and arable soils. Our data support the hypothesis and suggest that concentration of readily decomposable C substrate (as glucose equivalents and temperature dependent substrate release are the important factors controlling temperature sensitivity of soil respiration. The highest temperature sensitivity of soil respiration was observed when substrate release was temperature dependent and C substrate concentration was much lower than Ks. Increase of substrate content to the half-saturation constant by glucose addition resulted in temperature acclimation associated with the canceling effect. Addition of the substrate to the level providing respiration at a maximal rate Vmax leads to the acclimation of the whole microbial community as such. However, growing microbial biomass was more sensitive to the temperature alterations. This study improves our understanding of the instability of temperature sensitivity of soil respiration under field conditions, attributing this phenomenon to changes in concentration of readily decomposable C substrate.

  16. Strategizing a Comprehensive Laboratory Protocol to Determine the Decomposability of Soil Organic Matter in Permafrost

    Science.gov (United States)

    Schaedel, C.; Ernakovich, J. G.; Harden, J. W.; Natali, S.; Richter, A.; Schuur, E.; Treat, C. C.

    2015-12-01

    Soil organic matter decomposition depends on physical, chemical, and biological factors, such as the amount and quality of the organic matter stored, abiotic conditions (such as soil temperature and moisture), microbial community dynamics, and physical protection by soil minerals. Soils store immense amounts of carbon with 1330-1580 Pg of carbon in the permafrost region alone. Increasing temperatures in the Arctic will thaw large amounts of previously frozen organic carbon making it available for decomposition. The rate at which carbon is being released from permafrost soils is crucial for understanding future changes in permafrost carbon storage and carbon flux to the atmosphere. The potential magnitude and form of carbon release (carbon dioxide or methane) from permafrost can be investigated using soil incubation studies. Over the past 20 years, many incubation studies have been published with soils from the permafrost zone and three recent syntheses have summarized current findings from aerobic and anaerobic incubation studies. However, the breadth of the incubation synthesis projects was hampered by incomplete meta-data and the use of different methods. Here, we provide recommendations to improve and standardize future soil incubation studies (which are not limited to permafrost soils) to make individual studies useful for inclusion in syntheses and meta-analyses, which helps to broaden their impact on our understanding of organic matter cycling. Additionally, we identify gaps in the understanding of permafrost carbon decomposability, that, when coupled with emerging knowledge from field observations and experiments, can be implemented in future studies to gain a better overview of the overall decomposability of permafrost carbon.

  17. Temperature sensitivity of soil respiration is dependent on readily decomposable C substrate concentration

    Directory of Open Access Journals (Sweden)

    A. A. Larionova

    2007-06-01

    Full Text Available Temperature acclimation of soil organic matter (SOM decomposition is one of the major uncertainties in predicting soil CO2 efflux by the increase in global mean temperature. A reasonable explanation for an apparent acclimation proposed by Davidson and colleagues (2006 based on Michaelis-Menten kinetics suggests that temperature sensitivity decreases when both maximal activity of respiratory enzymes (Vmax and half- saturation constant (Ks cancel each other upon temperature increase. We tested the hypothesis of the canceling effect by the mathematical simulation of the data obtained in the incubation experiments with forest and arable soils. Our data confirm the hypothesis and suggest that concentration of readily decomposable C substrate as glucose equivalent is an important factor controlling temperature sensitivity. The highest temperature sensitivity was observed when C substrate concentration was much lower than Ks. Increase of substrate content to the half-saturation constant resulted in temperature acclimation associated with the canceling effect. Addition of the substrate to the level providing respiration at a maximal rate Vmax leads to the acclimation of the whole microbial community as such. However, growing microbial biomass was more sensitive to the temperature alterations. This study improves our understanding of the instability of temperature sensitivity of soil respiration under field conditions, explaining this phenomenon by changes in concentration of readily decomposable C substrate. It is worth noting that this pattern works regardless of the origin of C substrate: production by SOM decomposition, release into the soil by rhizodeposition, litter fall or drying-rewetting events.

  18. Strategizing a comprehensive laboratory protocol to determine the decomposability of soil organic matter in permafrost

    Science.gov (United States)

    Schaedel, C.; Ernakovich, J. G.; Harden, J. W.; Natali, S.; Richter, A.; Schuur, E.; Treat, C. C.

    2016-12-01

    Soil organic matter decomposition depends on physical, chemical, and biological factors, such as the amount and quality of the organic matter stored, abiotic conditions (such as soil temperature and moisture), microbial community dynamics, and physical protection by soil minerals. Soils store immense amounts of carbon with 1330-1580 Pg of carbon in the permafrost region alone. Increasing temperatures in the Arctic will thaw large amounts of previously frozen organic carbon making it available for decomposition. The rate at which carbon is being released from permafrost soils is crucial for understanding future changes in permafrost carbon storage and carbon flux to the atmosphere. The potential magnitude and form of carbon release (carbon dioxide or methane) from permafrost can be investigated using soil incubation studies. Over the past 20 years, many incubation studies have been published with soils from the permafrost zone and multiple recent syntheses have summarized current findings from aerobic and anaerobic incubation studies. However, the breadth of the synthesis projects was hampered by incomplete meta-data and the use of different methods. Here, we provide recommendations to improve and standardize future soil incubation studies (which are not limited to permafrost soils) to make individual studies useful for inclusion in syntheses and meta-analyses, which helps to broaden their impact and our understanding of organic matter cycling. Additionally, we identify gaps in the understanding of permafrost carbon decomposability, that, when coupled with emerging knowledge from field observations and experiments, can be incorporated into future studies to gain a better overview of the overall decomposability of permafrost carbon.

  19. Fast Anisotropic Gauss Filtering

    NARCIS (Netherlands)

    Geusebroek, J.M.; Smeulders, A.W.M.; van de Weijer, J.; Heyden, A.; Sparr, G.; Nielsen, M.; Johansen, P.

    2002-01-01

    We derive the decomposition of the anisotropic Gaussian in a one dimensional Gauss filter in the x-direction followed by a one dimensional filter in a non-orthogonal direction phi. So also the anisotropic Gaussian can be decomposed by dimension. This appears to be extremely efficient from a computin

  20. Fast Anisotropic Gauss Filters

    NARCIS (Netherlands)

    Geusebroek, J.M.; Smeulders, A.W.M.; van de Weijer, J.

    2003-01-01

    We derive the decomposition of the anisotropic Gaussian in a one dimensional Gauss filter in the x-direction phi. So also the anisotropic Gaussian can be decomposed by dimension. This appears to be extremely efficient from a computing perspective. An implementation scheme for normal covolution and f

  1. A Quasi-Thermodynamic Model of MOVPE of InGaN

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A quasi-thermodynamic model of MOVPE growth of InxGa1-xN alloys has been proposed with TMGa, TMIn and ammonia as source materials. In this improved model, the effect of low decomposition rate of ammonia is considered and the number of moles is used to express the mass conservation constraints on element N, H, In and Ga. It is assumed that the alloy was synthesized by the reactions between ammonia and group Ⅲ elements. The equilibrium partial pressures over the InxGa1-xN have been calculated. For the InxCa1-xalloys the relationship between the input vapor and the deposited solid composition has been calculated and the results compared with the literature data. The good agreement on the compositions from calculation and the experiment shows that our improved model is suitable for applying to the In xGa1- xNalloys grown by MOVPE. It is difficult for InxGa1-xN alloy to grow, especially for high-indium alloys, because InxGa1-xN is an immiscible alloy and InN has a very high In vapor pressure. It is also shown that gallium has strong tendency of preferential incorporation into the InxGa1-xN alloy. In order to enhance the incorporation of indium into the InGaN, we should use the lower growth-temperature ,lower reactor pressure, higher input V/Ⅲ ratio and higher nitrogen fraction in the carrier gas, in addition, the decomposed fraction of ammonia should also be reduced. Indium droplets would be deoosed if the growing conditions were not selected properly.

  2. Internal luminescence efficiencies in InGaP/GaAs/Ge triple-junction solar cells evaluated from photoluminescence through optical coupling between subcells

    Science.gov (United States)

    Tex, David M.; Imaizumi, Mitsuru; Akiyama, Hidefumi; Kanemitsu, Yoshihiko

    2016-12-01

    In-situ characterization is one of the most powerful techniques to improve material quality and device performance. Especially in view of highly efficient tandem solar cells this is an important issue for improving the cost-performance ratio. Optical techniques are suitable characterization methods, since they are non-destructing and contactless. In this work, we measured the power dependence of photoluminescence (PL) from the InGaP and GaAs subcells of an industry-standard triple-junction solar cell. High luminescence yields enhance the luminescence coupling, which was directly verified by time-resolved PL measurements. We present a new method to determine the internal luminescence efficiencies of InGaP and GaAs subcells with the aid of luminescence coupling. High luminescence efficiencies of 90% for GaAs and more than 20% for InGaP were found, which suggest that the material quality of the grown GaAs layer is excellent while the intrinsic luminescence limit of InGaP is still not reached even for high excitation conditions. The PL method is useful for probing the intrinsic material properties of the subcells in flat band condition, without influence of transport. Since no calibration of absolute PL is required, a fast screening of the material quality is possible, which should be extremely helpful for the solar cell industry.

  3. Molecular sexing of tucuxi dolphins (Sotalia guianensis and Sotalia fluviatilis using samples from biopsy darting and decomposed carcasses

    Directory of Open Access Journals (Sweden)

    Haydée A. Cunha

    2007-01-01

    Full Text Available We tested the zinc-finger sex chromosome-linked genes Zfx/Zfy and the sex-determining region Y (Sry genes for gender determination of biopsy samples from marine and riverine tucuxi dolphins (Sotalia guianensis and S. fluviatilis. We also evaluated the performance of these genes with decomposed carcasses, for which sexing cannot rely on the direct examination of the reproductive tract. Both systems proved reliable for sexing 46 fresh and decomposed samples, making them especially useful when biopsy darting is coupled with photo-identification studies.

  4. MATLAB tensor classes for fast algorithm prototyping.

    Energy Technology Data Exchange (ETDEWEB)

    Bader, Brett William; Kolda, Tamara Gibson (Sandia National Laboratories, Livermore, CA)

    2004-10-01

    Tensors (also known as mutidimensional arrays or N-way arrays) are used in a variety of applications ranging from chemometrics to psychometrics. We describe four MATLAB classes for tensor manipulations that can be used for fast algorithm prototyping. The tensor class extends the functionality of MATLAB's multidimensional arrays by supporting additional operations such as tensor multiplication. The tensor as matrix class supports the 'matricization' of a tensor, i.e., the conversion of a tensor to a matrix (and vice versa), a commonly used operation in many algorithms. Two additional classes represent tensors stored in decomposed formats: cp tensor and tucker tensor. We descibe all of these classes and then demonstrate their use by showing how to implement several tensor algorithms that have appeared in the literature.

  5. Kinetics versus thermodynamics of the metal incorporation in molecular beam epitaxy of (InxGa1−x2O3

    Directory of Open Access Journals (Sweden)

    Patrick Vogt

    2016-08-01

    Full Text Available We present a detailed study of the reaction kinetics and thermodynamics of the plasma-assisted oxide molecular beam epitaxy of the ternary compound (InxGa1−x2O3 for 0 ≤ x ≤ 1. We measured the growth rate of the alloy in situ by laser reflectrometry as a function of growth temperature TG for different metal-to-oxygen flux ratios rMe, and nominal In concentrations xnom in the metal flux. We determined ex situ the In and Ga concentrations in the grown film by energy dispersive X-ray spectroscopy. The measured In concentration x shows a strong dependence on the growth parameters TG, rMe, and xnom whereas growth on different co-loaded substrates shows that in the macroscopic regime of ∼μm3 x does neither depend on the detailed layer crystallinity nor on crystal orientation. The data unveil that, in presence of In, Ga incorporation is kinetically limited by Ga2O desorption the same way as during Ga2O 3 growth. In contrast, In incorporation during ternary growth is thermodynamically suppressed by the presence of Ga due to stronger Ga–O bonds. Our experiments revealed that Ga adatoms decompose/etch the In–O bonds whereas In adatoms do not decompose/etch the Ga–O bonds. This result is supported by our thermochemical calculations. In addition we found that a low TG and/or excessively low rMe kinetically enables In incorporation into (InxGa1−x2O3. This study may help growing high-quality ternary compounds (InxGa1−x2O3 allowing band gap engineering over the range of 2.7–4.7 eV.

  6. TMR study of GaMnAs/AlGaAs:Be/GaMnAs trilayers

    Science.gov (United States)

    Hagmann, Joseph; Liu, Xinyu; Dobrowolska, Malgorzata; Furdyna, Jacek; Yoo, Taehee; Khym, Sungwon; Lee, Sanghoon

    2011-03-01

    GaMnAs/GaAs:Be/GaMnAs trilayers have recently demonstrated antiferromagnetic (AFM) coupling between the two ferromagnetic (FM) layers, mediated by holes in the spacer layer. In this work, GaMnAs/ Al x Ga 1-x :Be/GaMnAs trilayer samples with varying Al concentrations were fabricated into magnetic tunnel junction (MTJ) devices with range of pillar diameters to measure tunneling magnetoresistance (TMR) under various conditions. SQUID measurements were use to measure the magnetization of the samples, including switching fields for parallel and antiparallel magnetization alignments of the FM layers. TMR was observed in the sample with Al 0.22 Ga 0.78 As:Be spacer, but was massively suppressed in the samples with lower Al content. The presence of holes in the spacer layer is shown to suppress TMR. This illustrates the difference in conditions for TMR and for AFM interlayer coupling. Supported by NSF Grant DMR-1005851 and OISE-1015458.

  7. (68) Ga-labeled Ciprofloxacin Conjugates as Radiotracers for Targeting Bacterial Infection.

    Science.gov (United States)

    Satpati, Drishty; Arjun, Chanda; Krishnamohan, Repaka; Samuel, Grace; Banerjee, Sharmila

    2016-05-01

    With an aim of developing a bacteria-specific molecular imaging agent, ciprofloxacin has been modified with a propylamine spacer and linked to two common bifunctional chelators, p-SCN-Bz-DOTA and p-SCN-Bz-NOTA. The two ciprofloxacin conjugates, CP-PA-SCN-Bz-DOTA (1) and CP-PA-SCN-Bz-NOTA (2), were radiolabeled with (68)Ga in >90% radiochemical yield and were moderately stable in vitro for 4 h. The efficacy of (68)Ga-1 and (68)Ga-2 has been investigated in vitro in Staphylococcus aureus cells where bacterial binding of the radiotracers (0.9-1.0% for (68)Ga-1 and 1.6-2.3% for (68)Ga-2) could not be blocked in the presence of excess amount of unlabeled ciprofloxacin. However, uptake of radiotracers in live bacterial cells was significantly higher (p 68)Ga-1 and (68)Ga-2 was tested in vivo in rats where the infected muscle-to-inflamed muscle ((68)Ga-1: 2 ± 0.2, (68)Ga-2: 3 ± 0.5) and infected muscle-to-normal muscle ratios ((68)Ga-1: 3 ± 0.4, (68)Ga-2: 6.6 ± 0.8) were found to improve at 120 min p.i. Fast blood clearance and renal excretion was observed for both the radiotracers. The two (68)Ga-labeled infection targeting radiotracers could discriminate between bacterial infection and inflammation in vivo and are worthy of further detailed investigation as infection imaging agents at the clinical level.

  8. Environments of Ga in MFI-type Ga-silicates and their catalytic performance; MFI gata Ga-silicate chu no Ga no sonzai jotai to shokubai seino

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, H.; Takiyama, Y.; Higashida, K.; Otsuka, S.; Kishida, M.; Wakabayashi, K. [Kyushu University, Fukuoka (Japan); Shoji, H. [Maruzen Petrochemical Co. Ltd., Chiba (Japan)

    1998-07-01

    MFI-type Ga-silicates (GaS) of varying atomic Si/Ga ratio are synthesized from the gel stocks, to compare them one another for their properties and C4H10 conversion performance. GaS (M) synthesized by the Mobil method shows a broader Ga-MASNMR spectral peak relevant to the GaO4 tetrahedron and lower unit cell increase rate, when it contains a high proportion of Ga, than GaS (A) synthesized by the alkoxide method. It is therefore considered that GaS (M) has an increased content of the GaO4 tetrahedron of low symmetry, as Ga content increases. GaS (M) loses a larger quantity of Ga eluted out as a result of HCl treatment than GaS (A), indicating that the former contains the GaO4 tetrahedron of low symmetry under a less stable condition. GaS (M) gives a higher aromatic hydrocarbon yield in the C4H10 conversion than GaS (A), as its Ga content increases. This results from difference between their dehydrogenation performances, indicating that Ga in the GaO4 tetrahedron of lower symmetry has a higher dehydrogenation performance. 19 refs., 6 figs., 3 tabs.

  9. The Effect of Visual and Etymological Treatments on Learning Decomposable Idioms among EFL Learners

    Directory of Open Access Journals (Sweden)

    Nassim Golaghaei

    2015-09-01

    Full Text Available The present study endeavors to investigate the impact of visual and etymological treatments on learning idioms among English language learners. Seventy-nine intermediate students at Rooz Academy Language School in Babol were selected from among a total number of 116 learners based on their performances on the Longman complete course for the TOEFL test to fulfill the purpose of the study. The students were then assigned into three experimental groups. Initially, a pre-test of idiomatic expressions including 48 idiomatic items was administered to the participants in all groups. During the instructional period, the groups were taught a group of abnormally decomposable idioms through different treatments, namely, visual, etymological, and a combination of visual-etymological elaboration. At the end of the instructional period, the participants in all groups were given a posttest which was the same as the pretest. The design of this study is quasi-experimental. The data obtained was analyzed using one-way ANOVA analysis. The results of data analysis revealed that the etymological treatment was more effective than visual aids on learning idioms among intermediate English language learners. However, the visual-etymological treatment was the most effective one. The findings of this study have implications for EFL teachers, students, and materials developers. Keywords: Visualization, Etymology, Idiom, Dual coding theory

  10. Utility of forensic detection of rabies virus in decomposed exhumed dog carcasses

    Directory of Open Access Journals (Sweden)

    Wanda Markotter

    2015-03-01

    Full Text Available This report describes four suspected rabies cases in domestic dogs that were involved inhuman exposures. In all these cases, the animals were buried for substantial times beforerabies testing was performed. Animal rabies is endemic in South Africa and domestic dogsare the main vector for transmission to humans. Diagnosis of rabies in humans is complicated,and diagnosis in the animal vector can provide circumstantial evidence to support clinicaldiagnosis of rabies in humans. The gold standard diagnostic method, fluorescent antibodytest (FAT, only delivers reliable results when performed on fresh brain material and thereforedecomposed samples are rarely submitted for diagnostic testing. Severely decomposed brainmaterial was tested for the presence of rabies virus genomic material using a quantitativereal-time reverse transcription polymerase chain reaction (q-real-time RT-PCR assaywhen conventional molecular methods were unsuccessful. This may be a useful tool in theinvestigation of cases where the opportunity to sample the suspected animals post mortem wasforfeited and which would not be possible with conventional testing methodologies becauseof the decomposition of the material.

  11. Does drought modify the decomposability of grassland species ? An incubation study

    Science.gov (United States)

    Gouskov, B.; Heim, A.; Abiven, S.

    2009-04-01

    Climate projections in Europe predict an increase in length and frequency of droughts within the next decades. This might be particularly an issue in sensitive ecosystems that are considered as carbon sink, like for example alpine grasslands. A variation in moisture content directly affects both litter decomposition and biomass production. Additionally, drought may alsopotentially affect the biochemical quality of plant litter reaching the soil. Under water limiting conditions, significant modifications of plant tissues composition have been observed (for example an increase of the cutin content), which could modify decomposition dynamics of the litter layer. In this study, we followed the decomposition of three grassland species (Poa pratensis L., Lolium multiflorum et Trifolium repens L.) that grew i/ under real climate and ii/ during an artificial drought. These plants were sampled on an experimental site (Chamau, Switzerland) during a three-year drought simulation experiment. The biochemical characteristics of the different plants were estimated by C, N content, water-soluble C, Diffuse Reflectance Infrared Fourier Transform Spectroscopy and lignin CuO oxidation. We followed the microbial community structure before and after the decomposition study using a Biolog system. The decomposition of the organic matter was followed under controlled conditions (23°C, water level regularly adjusted). The decomposition dynamics were measured by CO2 trapping in NaOH. First results show that Trifolium litter that grew under drought decomposes more slowly than one that grew under regular conditions. No significant difference was found for the other species.

  12. Particle Communication and Domain Neighbor Coupling: Scalable Domain Decomposed Algorithms for Monte Carlo Particle Transport

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, M. J.; Brantley, P. S.

    2015-01-20

    In order to run Monte Carlo particle transport calculations on new supercomputers with hundreds of thousands or millions of processors, care must be taken to implement scalable algorithms. This means that the algorithms must continue to perform well as the processor count increases. In this paper, we examine the scalability of:(1) globally resolving the particle locations on the correct processor, (2) deciding that particle streaming communication has finished, and (3) efficiently coupling neighbor domains together with different replication levels. We have run domain decomposed Monte Carlo particle transport on up to 221 = 2,097,152 MPI processes on the IBM BG/Q Sequoia supercomputer and observed scalable results that agree with our theoretical predictions. These calculations were carefully constructed to have the same amount of work on every processor, i.e. the calculation is already load balanced. We also examine load imbalanced calculations where each domain’s replication level is proportional to its particle workload. In this case we show how to efficiently couple together adjacent domains to maintain within workgroup load balance and minimize memory usage.

  13. Advanced oxidation processes of decomposing dichloroacetic acid and trichloroacetic acid in water

    Institute of Scientific and Technical Information of China (English)

    WANG Kun-ping; GUO Jin-song; YANG Min; JUNJI Hirotsuji; DENG Rong-sen; LIU Wei

    2008-01-01

    We studied the decomposition of two haloacetic acids (HAAs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), in water by single oxidants ozone (O3) and ultraviolet radiation (UV) and the advanced oxidation processes (AOPs) constituted by the combinations of O3/UV, H2O2/UV, O3 /H2O2, and O3/H2O2/UV. The concentrations of HAAs were analyzed at specified time intervals to track their decomposition. Except for O3 and UV, the four combined oxidation processes remarkably enhance the decomposition of DCAA and TCAA owing to the generated very reactive hydroxyl radicals. The fastest decomposition process is O3/H2O2/UV, closely followed by O3/UV. DCAA is much easier to decompose than TCAA. The kinetics of HAA decomposition by O3/UV can be described well by a pseudo first-order reaction model under a constant initial dissolved O3 concentration and fixed UV radiation. Humic acids and HCO3- in the reaction system both decrease the decomposition rate constants for DCAA and TCAA. The amount of H2O2 accumulates in the presence of humic acids in the O3/UV process.

  14. Decomposing Dusty Galaxies. I. Multi-Component Spectral Energy Distribution Fitting

    CERN Document Server

    Marshall, J A; Armus, L; Charmandaris, V; Spoon, H W W; Bernard-Salas, J; Houck, J R

    2007-01-01

    We present a new multi-component spectral energy distribution (SED) decomposition method and use it to analyze the ultraviolet to millimeter wavelength SEDs of a sample of dusty infrared-luminous galaxies. SEDs are constructed from spectroscopic and photometric data obtained with the Spitzer Space Telescope, in conjunction with photometry from the literature. Each SED is decomposed into emission from populations of stars, an AGN accretion disk, PAHs, atomic and molecular lines, and distributions of graphite and silicate grains. Decompositions of the SEDs of the template starburst galaxies NGC7714 and NGC2623 and the template AGNs PG0804+761 and Mrk463 provide baseline properties to aid in quantifying the strength of star-formation and accretion in the composite systems NGC6240 and Mrk1014. We find that obscured radiation from stars is capable of powering the total dust emission from NGC6240, although we cannot rule out a contribution from a deeply embedded AGN visible only in X-rays. The decomposition of Mrk1...

  15. High-throughput nucleotide sequence analysis of diverse bacterial communities in leachates of decomposing pig carcasses

    Directory of Open Access Journals (Sweden)

    Seung Hak Yang

    2015-09-01

    Full Text Available The leachate generated by the decomposition of animal carcass has been implicated as an environmental contaminant surrounding the burial site. High-throughput nucleotide sequencing was conducted to investigate the bacterial communities in leachates from the decomposition of pig carcasses. We acquired 51,230 reads from six different samples (1, 2, 3, 4, 6 and 14 week-old carcasses and found that sequences representing the phylum Firmicutes predominated. The diversity of bacterial 16S rRNA gene sequences in the leachate was the highest at 6 weeks, in contrast to those at 2 and 14 weeks. The relative abundance of Firmicutes was reduced, while the proportion of Bacteroidetes and Proteobacteria increased from 3–6 weeks. The representation of phyla was restored after 14 weeks. However, the community structures between the samples taken at 1–2 and 14 weeks differed at the bacterial classification level. The trend in pH was similar to the changes seen in bacterial communities, indicating that the pH of the leachate could be related to the shift in the microbial community. The results indicate that the composition of bacterial communities in leachates of decomposing pig carcasses shifted continuously during the study period and might be influenced by the burial site.

  16. Utility of forensic detection of rabies virus in decomposed exhumed dog carcasses.

    Science.gov (United States)

    Markotter, Wanda; Coertse, Jessica; le Roux, Kevin; Peens, Joey; Weyer, Jacqueline; Blumberg, Lucille; Nel, Louis H

    2015-05-18

    This report describes four suspected rabies cases in domestic dogs that were involved inhuman exposures. In all these cases, the animals were buried for substantial times beforerabies testing was performed. Animal rabies is endemic in South Africa and domestic dogsare the main vector for transmission to humans. Diagnosis of rabies in humans is complicated,and diagnosis in the animal vector can provide circumstantial evidence to support clinicaldiagnosis of rabies in humans. The gold standard diagnostic method, fluorescent antibodytest (FAT), only delivers reliable results when performed on fresh brain material and thereforedecomposed samples are rarely submitted for diagnostic testing. Severely decomposed brainmaterial was tested for the presence of rabies virus genomic material using a quantitativereal-time reverse transcription polymerase chain reaction (q-real-time RT-PCR) assaywhen conventional molecular methods were unsuccessful. This may be a useful tool in theinvestigation of cases where the opportunity to sample the suspected animals post mortem wasforfeited and which would not be possible with conventional testing methodologies becauseof the decomposition of the material.

  17. Turning pyridoxine into a catalytic chain-breaking and hydroperoxide-decomposing antioxidant.

    Science.gov (United States)

    Singh, Vijay P; Poon, Jia-fei; Engman, Lars

    2013-02-15

    Vitamin B6 is involved in a variety of enzymatic transformations. Some recent findings also indicate an antioxidant role of the vitamin in biological systems. We set out to turn pyridoxine (1a) into a catalytic chain-breaking and hydroperoxide-decomposing antioxidant by replacing the 2-methyl substituent with an alkyltelluro group. Target molecules 12 and derivatives 14, 17, 18, and 20 thereof were accessed by subjecting suitably substituted 2-halopyridin-3-ols to aromatic substitution using sodium alkanetellurolates as nucleophiles and then LAH-reduction of ester groups. The novel pyridoxine compounds were found to inhibit azo-initiated peroxidation of linoleic acid an order of magnitude more efficiently than α-tocopherol in a water/chlorobenzene two-phase system containing N-acetylcysteine as a reducing agent in the aqueous phase. The most lipid-soluble pyridoxine derivative 20c was regenerable and could inhibit peroxidation for substantially longer time (>410 min) than α-tocopherol (87 min). The chalcogen-containing pyridoxines could also mimic the action of the glutathione peroxidase enzymes. Thus, compound 20a catalyzed reduction of hydrogen peroxide three times more efficiently than Ebselen in the presence of glutathione as a stoichiometric reducing agent.

  18. Factors Affecting Isfahanian Mobile Banking Adoption Based on the Decomposed Theory of Planned Behavior

    Directory of Open Access Journals (Sweden)

    Ali Kazemi

    2013-07-01

    Full Text Available Mobile banking is considered a new era in banking, in which banks are spending considerable amount of money to have it available to their customers and to cut their operations costs. The current exploratory study is an attempt to investigate the factors that influence Isfahanian’ intention to adopt mobile banking by extending the renowned framework of Decomposed Theory of Planned Behavior model (DTPB by additionally examining the effects of trust and perceived risk as components of attitude on behavioral intention. A self-administrated questionnaire had been developed and distributed in Isfahan city. Out of 400 questionnaires that have been distributed, 315 are returned (78.0%. Of these, five (5 responses had to be discarded due to invalid or incomplete data entries. Thus the sample comprising of a total of 310 respondents was used for analysis. The data was analyzed by AMOS software. Results of the study discovered that the decisive or crucial factors influencing mobile banking adoption are attitude and perceived behavioral control, However, social norms were the only factor found insignificant. The perceived usefulness, perceived ease of use ,compatibility, and trust under 'behavioral attitude' have positive effect on behavioral attitude; while perceived risk under 'behavioral attitude' has negative effect on behavioral attitude. the influence of the interpersonal influence under 'subjective norms' was also evident, while self-efficacy and facilitating condition under 'perceived behavioral control' are significant influential factors.

  19. The potential and limits of termites (Isoptera) as decomposers of waste paper products.

    Science.gov (United States)

    Lenz, Michael; Lee, Chow-Yang; Lacey, Michael J; Yoshimura, Tsuyoshi; Tsunoda, Kunio

    2011-02-01

    Termites (Isoptera) have often been proposed as decomposers oflignocellulosic waste, such as paper products, while termite biomass could be harvested for food supplements. Groups of Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe) were kept for 4 and 8 wk, respectively, in the laboratory and given up to 10 different types of paper as their food source. Paper consumption, survival, caste composition, and lipid content were recorded. Corrugated cardboard was by far the most consumed paper product, although survival on it was not necessarily favorable. In R. speratus, lipid reserves and neotenic numbers were quite high, but no breeding occurred. Cardboard may be the "junk food" equivalent for termites. Within the tested period, termites did not perform well on paper products that form the bulk of waste paper--corrugated cardboard, newsprint, and pamphlets and magazines. On all paper products (except recycled office paper), neotenic reproductives were formed, but larvae were observed only on kraft pulp and tissue paper. That all waste paper products contain lignocellulosic fibers does not automatically make them suitable for decomposition by termites. Each paper product has to be assessed on its own merit to see whether termites can reproduce on this diet, if it were to be a candidate for sustainable "termidegradation" and termite biomass production.

  20. Decomposing the Drivers of Past, Present, and Future Land Use Change

    Science.gov (United States)

    Calvin, K. V.; Wise, M. A.

    2015-12-01

    Over the past 500 years, global agricultural area has grown from 2 million km2 (1500) to 15 million km2 (2005), displacing forests and other natural ecosystems in the process (Hurtt et al., 2011). This expansion in area has been driven by changes in population, income, diet, and agricultural productivity. These factors will continue to evolve in the future; however, the effect of these changes on future land use, land cover, and emissions remains uncertain (e.g., Calvin et al., In Press). Additionally, future changes in land depend critically on the implementation of land-based mitigation options, such as bioenergy and afforestation (Wise et al., 2009; Reilly et al., 2012; Popp et al., 2013; Calvin et al., 2014). As all of these factors are uncertain in the future, the future evolution of land use and land cover is also uncertain. This presentation decomposes the drivers of past, present, and future land use change, characterizing the contribution of factors such as population, income, diet, agricultural productivity, and mitigation. In the historical period, we rely on a variety of land-based datasets (e.g., FAO, HYDE). For the future period, we analyze the integrated assessment modeling community's implementation of the Shared Socioeconomic Pathways (SSPs; O'Neill et al., In Press). The SSPs describe five different evolutions of socioeconomic development, varying several factors relevant to land use and land use change.

  1. A spectral analysis of the domain decomposed Monte Carlo method for linear systems

    Energy Technology Data Exchange (ETDEWEB)

    Slattery, Stuart R., E-mail: slatterysr@ornl.gov [Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831 (United States); Evans, Thomas M., E-mail: evanstm@ornl.gov [Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831 (United States); Wilson, Paul P.H., E-mail: wilsonp@engr.wisc.edu [University of Wisconsin - Madison, 1500 Engineering Dr., Madison, WI 53706 (United States)

    2015-12-15

    The domain decomposed behavior of the adjoint Neumann-Ulam Monte Carlo method for solving linear systems is analyzed using the spectral properties of the linear operator. Relationships for the average length of the adjoint random walks, a measure of convergence speed and serial performance, are made with respect to the eigenvalues of the linear operator. In addition, relationships for the effective optical thickness of a domain in the decomposition are presented based on the spectral analysis and diffusion theory. Using the effective optical thickness, the Wigner rational approximation and the mean chord approximation are applied to estimate the leakage fraction of random walks from a domain in the decomposition as a measure of parallel performance and potential communication costs. The one-speed, two-dimensional neutron diffusion equation is used as a model problem in numerical experiments to test the models for symmetric operators with spectral qualities similar to light water reactor problems. In general, the derived approximations show good agreement with random walk lengths and leakage fractions computed by the numerical experiments.

  2. Using decision models to decompose anxiety-related bias in threat classification.

    Science.gov (United States)

    White, Corey N; Skokin, Kimberly; Carlos, Brandon; Weaver, Alexandria

    2016-03-01

    Individuals with high levels of anxiety show preferential processing of threatening information, and this cognitive bias is thought to be an integral component of anxiety disorders. In threat classification tasks, this bias manifests as high-anxiety participants being more likely to classify stimuli as threatening than their low-anxiety counterparts. However, it is unclear which cognitive mechanisms drive this bias in threat classification. To better understand this phenomenon, threat classification data were analyzed with 2 decision models: a signal detection model and a drift-diffusion model. Signal detection models can dissociate measures of discriminability and bias, and diffusion models can further dissociate bias due to response preparation from bias due to stimulus evaluation. Individuals in the study completed a trait anxiety measure and classified threatening and neutral words based on whether they deemed them threatening. Signal detection analysis showed that high-anxiety participants had a bias driven by a weaker threat criterion than low-anxiety participants, but no differences in discriminability. Drift-diffusion analysis further decomposed the threat bias to show that it is driven by both an expectation bias that the threat response was more likely to be correct, and a stimulus bias driven by a weaker criterion for evaluating the stimuli under consideration. These model-based analyses provide valuable insight and show that multiple cognitive mechanisms underlie differential threat processing in anxiety. Implications for theories of anxiety are discussed.

  3. Adsorption performance of Rh decorated SWCNT upon SF6 decomposed components based on DFT method

    Science.gov (United States)

    Zhang, Xiaoxing; Cui, Hao; Dong, Xingchen; Chen, Dachang; Tang, Ju

    2017-10-01

    Transition metal decorated carbon nanotubes (CNTs) applied in the field of gas adsorption and storage have in recent years accepted considerable attentions because of their superior adsorbing performance. In electrical engineering, they are employed as adsorbents to remove the decomposed products of SF6 caused by partial discharge, for guaranteeing the insulation status of gas insulation switchgear (GIS). In this paper, Rh doped SWCNT is introduced to investigate its adsorption properties towards typical gases of SF6 based on density functional theory (DFT) method. Both single and double molecules adsorbing systems were performed to investigate the adsorption ability of proposed material. Results indicate that Rh-CNT, which has strong interaction with defined gas molecules, is a promising material for SF6 decompositions adsorption especially SO2 and SOF2 that exhibit topmost sensitivity to the modified surface. Therefore, we suggest the Rh-CNT to be an adsorbent to be applied in GIS for guaranteeing the operation state of such devices and even to be exploited as gas sensor to evaluate the insulation state of the power system. Our calculations would provide experimentalist with a first insight into physicochemical properties of this material.

  4. A phytotoxic active substance in the decomposing litter of the fern Gleichenia japonica.

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Saito, Yoshihumi; Ohno, Osamu; Suenaga, Kiyotake

    2015-03-15

    The fern Gleichenia japonica often dominates plant communities by forming large monospecific stands throughout the temperate to tropical Asia. The objective of this study was the investigation of allelopathic property and substances of the decomposing litter of the fern to evaluate the possible involvement of its allelopathy in the domination. An aqueous methanol extract of G. japonica litter inhibited the growth of garden cress (Lepidium sativum), lettuce (Lactuca sativa), barnyard grass (Echinochloa crus-galli), and ryegrass (Lolium multiflorum). This result suggests that G. japonica litter contains growth inhibitory substances. The extract was purified by chromatography while monitoring the inhibitory activity, and a growth inhibitory substance was isolated. The chemical structure of the substance was determined by spectral data to be a novel compound, 13-O-β-fucopyranosyl-3β-hydroxymanool. This compound inhibited root and shoot growth of garden cress and barnyard grass at concentrations ranging from 89.7 to 271 μM for 50% inhibition. In addition, the compound had potent growth inhibitory activity with the soil taken from near the colony. The concentration of the compound in soil under a pure colony of G. japonica was 790 μM, suggesting that the compound may contribute to the establishment of monocultural stands by this fern.

  5. Obesity inequality in Malaysia: decomposing differences by gender and ethnicity using quantile regression.

    Science.gov (United States)

    Dunn, Richard A; Tan, Andrew K G; Nayga, Rodolfo M

    2012-01-01

    Obesity prevalence is unequally distributed across gender and ethnic group in Malaysia. In this paper, we examine the role of socioeconomic inequality in explaining these disparities. The body mass index (BMI) distributions of Malays and Chinese, the two largest ethnic groups in Malaysia, are estimated through the use of quantile regression. The differences in the BMI distributions are then decomposed into two parts: attributable to differences in socioeconomic endowments and attributable to differences in responses to endowments. For both males and females, the BMI distribution of Malays is shifted toward the right of the distribution of Chinese, i.e., Malays exhibit higher obesity rates. In the lower 75% of the distribution, differences in socioeconomic endowments explain none of this difference. At the 90th percentile, differences in socioeconomic endowments account for no more than 30% of the difference in BMI between ethnic groups. Our results demonstrate that the higher levels of income and education that accrue with economic development will likely not eliminate obesity inequality. This leads us to conclude that reduction of obesity inequality, as well the overall level of obesity, requires increased efforts to alter the lifestyle behaviors of Malaysians.

  6. A decomposable silica-based antibacterial coating for percutaneous titanium implant

    Science.gov (United States)

    Wang, Jia; Wu, Guofeng; Liu, Xiangwei; Sun, Guanyang; Li, Dehua; Wei, Hongbo

    2017-01-01

    Although percutaneous titanium implants have become one of the best choices as retainers in the facial defects, peri-implantitis still occurs at a significant rate. This unwanted complication occurs due to adhesion of bacteria and subsequent biofilm formation. To solve this problem, we have developed a novel antibiotic nanodelivery system based on self-decomposable silica nanoparticles. In this study, silica-gentamycin (SG) nanoparticles were successfully fabricated using an innovative one-pot solution. The nanoparticles were incorporated within a gelatin matrix and cross-linked on microarc-oxidized titanium. To characterize the SG nanoparticles, their particle size, zeta potential, surface morphology, in vitro drug release, and decomposition process were sequentially evaluated. The antibacterial properties against the gram-positive Staphylococcus aureus, including bacterial viability, antibacterial rate, and bacteria morphology, were analyzed using SG-loaded titanium specimens. Any possible influence of released gentamycin on the viability of human fibroblasts, which are the main component of soft tissues, was investigated. SG nanoparticles from the antibacterial titanium coating continuously released gentamycin and inhibited S. aureus growth. In vitro investigation showed that the obtained nanodelivery system has good biocompatibility. Therefore, this design can be further investigated as a method to prevent infection around percutaneous implants. PMID:28123297

  7. Wavelet analysis to decompose a vibration simulation signal to improve pre-distribution testing of packaging

    Science.gov (United States)

    Griffiths, K. R.; Hicks, B. J.; Keogh, P. S.; Shires, D.

    2016-08-01

    In general, vehicle vibration is non-stationary and has a non-Gaussian probability distribution; yet existing testing methods for packaging design employ Gaussian distributions to represent vibration induced by road profiles. This frequently results in over-testing and/or over-design of the packaging to meet a specification and correspondingly leads to wasteful packaging and product waste, which represent 15bn per year in the USA and €3bn per year in the EU. The purpose of the paper is to enable a measured non-stationary acceleration signal to be replaced by a constructed signal that includes as far as possible any non-stationary characteristics from the original signal. The constructed signal consists of a concatenation of decomposed shorter duration signals, each having its own kurtosis level. Wavelet analysis is used for the decomposition process into inner and outlier signal components. The constructed signal has a similar PSD to the original signal, without incurring excessive acceleration levels. This allows an improved and more representative simulated input signal to be generated that can be used on the current generation of shaker tables. The wavelet decomposition method is also demonstrated experimentally through two correlation studies. It is shown that significant improvements over current international standards for packaging testing are achievable; hence the potential for more efficient packaging system design is possible.

  8. Purification and Some Properties of a Tetrathionate Decomposing Enzyme from Thiobacillus thiooxidans.

    Science.gov (United States)

    Tano, T; Kitaguchi, H; Harada, M; Nagasawa, T; Sugio, T

    1996-01-01

    A tetrathionate-decomposing enzyme that catalyzes the decomposition of tetrathionate into thiosulfate and sulfate was purified to homogeneity from tetrathionate-grown Thiobacillus thiooxidans. The enzyme had an apparent molecular weight of 104,000, and was composed of two identical subunits (MW = 58,000) as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme had an isoelectric point at 9.6 and was most active at pH 3.0-3.5 and 40°C. Enzyme activity was increased approximately 100-fold in the presence of 400 mm sulfate ion. The Michaelis constant of this enzyme for tetrathionate in the presence of 20, 50, and 200 mm of sulfate ion was 2.4 mm. Mercuric and ferric ions completely inhibited the enzyme activity at 1 mm. Though cupric ion up to 0.01 mm markedly stimulated the activity in the presence of 20 mm sulfate ion, a higher concentration (1 mm) rather strongly inhibited the activity. Ethylenediaminetetraacetic acid (EDTA) strongly inhibited the activity, but this inhibiton was completely restored by cupric ion.

  9. On spinors, strings, integrable models and decomposed Yang-Mills theory

    CERN Document Server

    Ioannidou, Theodora; Niemi, Antti J

    2014-01-01

    This paper deals with various interrelations between strings and surfaces in three dimensional ambient space, two dimensional integrable models and two dimensional and four dimensional decomposed SU(2) Yang-Mills theories. Initially, a spinor version of the Frenet equation is introduced in order to describe the differential geometry of static three dimensional string-like structures. Then its relation to the structure of the su(2) Lie algebra valued Maurer-Cartan one-form is presented; while by introducing time evolution of the string a Lax pair is obtained, as an integrability condition. In addition, it is show how the Lax pair of the integrable nonlinear Schroedinger equation becomes embedded into the Lax pair of the time extended spinor Frenet equation and it is described how a spinor based projection operator formalism can be used to construct the conserved quantities, in the case of the nonlinear Schroedinger equation. Then the Lax pair structure of the time extended spinor Frenet equation is related to ...

  10. Decomposing passenger transport futures : Comparing results of global integrated assessment models

    NARCIS (Netherlands)

    Edelenbosch, O. Y.|info:eu-repo/dai/nl/412493373; McCollum, D. L.; van Vuuren, Detlef|info:eu-repo/dai/nl/11522016X; Bertram, C.; Carrara, S.; Daly, H.; Fujimori, S.; Kitous, A.; Kyle, P.; Ó Broin, E.; Karkatsoulis, P.; Sano, F.

    The transport sector is growing fast in terms of energy use and accompanying greenhouse gas emissions. Integrated assessment models (IAMs) are used widely to analyze energy system transitions over a decadal time frame to help inform and evaluating international climate policy. As part of this, IAMs

  11. Properties of InGaAs quantum dot saturable absorbers in monolithic mode-locked lasers

    DEFF Research Database (Denmark)

    Thompson, M.G.; Marinelli, C.; Chu, Y.

    Saturable absorbers properties are characterised in monolithic mode-locked InGaAs quantum dot lasers. We analyse the impact of weak quantum confined Stark effect, fast absorber recovery time and low absorber saturation power on the mode-locking performance.......Saturable absorbers properties are characterised in monolithic mode-locked InGaAs quantum dot lasers. We analyse the impact of weak quantum confined Stark effect, fast absorber recovery time and low absorber saturation power on the mode-locking performance....

  12. Gas sensitivity and sensing mechanism studies on Au-doped TiO₂ nanotube arrays for detecting SF₆ decomposed components.

    Science.gov (United States)

    Zhang, Xiaoxing; Yu, Lei; Tie, Jing; Dong, Xingchen

    2014-10-17

    The analysis to SF6 decomposed component gases is an efficient diagnostic approach to detect the partial discharge in gas-insulated switchgear (GIS) for the purpose of accessing the operating state of power equipment. This paper applied the Au-doped TiO2 nanotube array sensor (Au-TiO2 NTAs) to detect SF6 decomposed components. The electrochemical constant potential method was adopted in the Au-TiO2 NTAs' fabrication, and a series of experiments were conducted to test the characteristic SF6 decomposed gases for a thorough investigation of sensing performances. The sensing characteristic curves of intrinsic and Au-doped TiO2 NTAs were compared to study the mechanism of the gas sensing response. The results indicated that the doped Au could change the TiO2 nanotube arrays' performances of gas sensing selectivity in SF6 decomposed components, as well as reducing the working temperature of TiO2 NTAs.

  13. Understanding E-Learning Adoption among Brazilian Universities: An Application of the Decomposed Theory of Planned Behavior

    Science.gov (United States)

    Dos Santos, Luiz Miguel Renda; Okazaki, Shintaro

    2013-01-01

    This study sheds light on the organizational dimensions underlying e-learning adoption among Brazilian universities. We propose an organizational e-learning adoption model based on the decomposed theory of planned behavior (TPB). A series of hypotheses are posited with regard to the relationships among the proposed constructs. The model is…

  14. Understanding E-Learning Adoption among Brazilian Universities: An Application of the Decomposed Theory of Planned Behavior

    Science.gov (United States)

    Dos Santos, Luiz Miguel Renda; Okazaki, Shintaro

    2013-01-01

    This study sheds light on the organizational dimensions underlying e-learning adoption among Brazilian universities. We propose an organizational e-learning adoption model based on the decomposed theory of planned behavior (TPB). A series of hypotheses are posited with regard to the relationships among the proposed constructs. The model is…

  15. Decomposing change in life expectancy : A bouquet of formulas in honor of Nathan Keyfitz's 90th birthday

    NARCIS (Netherlands)

    Vaupel, JW; Romo, VC

    2003-01-01

    We extend Nathan Keyfitz research on continuous change in life expectancy over time by presenting and proving a new formula for decomposing such change. The formula separates change in life expectancy over time into two terms. The first term captures the general effect of reduction in death rates at

  16. Contactless electroreflectance study of a GaAIAs/lnGaAs/ GaAs/GaAIAs step quantum well structure

    Science.gov (United States)

    Moneger, S.; Qiang, H.; Pollak, Fred H.; Noble, T. F.

    1995-10-01

    Using contactless electroreflectance at 300 and 77K, we have studied the inter-subband transitions from a GaAlAs/InGaAs/GaAs/GaALAs step quantum well structure (small well inside a large well) consisting of two layers A (InxGa1-xAs) and B (GaAs) with widths LA and LB, respectively, bounded by two thick barrier regions of Gax AlyAs. By comparison of the observed spectral features with an envelope function calculation, including the effects of strain, we have been able to characterize the potential profile of the structure, i.e., LA, LB, x, and y. There is very good agreement between experiment and the intended materials param-eters. Such configurations are of considerable importance since (a) they form the basis for pseudomorphic high electron mobility transistors, and (b) also have applications in optoelectronics due to their large Stark shifts.

  17. Transmission electron microscopy analysis of phase separation in GaInAsSb films grown on GaSb substrate.

    Science.gov (United States)

    Szczeszek, P; Amariei, A; Schöne, J; Zoulis, G; Vouroutzis, N; Polychroniadis, E K; Stróz, D

    2006-10-01

    The GaSb-based quaternary alloys are a good choice for thermophotovoltaic applications. The thermophotovoltaic cell converts infrared radiation to electricity, using the same principles as photovoltaic devices. The aim of the present work was the microstructural study of such an alloy, namely Ga(0.84)In(0.16)As(0.12)Sb(0.88). A thin film of the material was grown by metal organic vapour phase epitaxy on a (100)alpha-->[111]B (alpha = 2 degrees, 4 degrees, 6 degrees) GaSb substrate. The GaInAsSb alloy has an appropriate band gap, but suffers from a phase separation consisting of GaAs-rich and InSb-rich regions that is disadvantageous for cell efficiency. In this work, we employed a morphological approach to phase separation, with the use of conventional transmission electron microscopy and atomic force microscopy. The phase separation occurs in two different orientations: parallel to the growth direction (vertical) and inclined (lateral). After application of fast Fourier transformation filtering, the vertical periodicity was found to be lambda = 5 nm for the pair (black and white) of layers independently of the cut-off angle, whereas the lateral periodicity was related to it.

  18. HCUP Fast Stats

    Data.gov (United States)

    U.S. Department of Health & Human Services — HCUP Fast Stats provides easy access to the latest HCUP-based statistics for health information topics. HCUP Fast Stats uses visual statistical displays in...

  19. Fast food (image)

    Science.gov (United States)

    Fast foods are quick, reasonably priced, and readily available alternatives to home cooking. While convenient and economical for a busy lifestyle, fast foods are typically high in calories, fat, saturated ...

  20. Fast food tips (image)

    Science.gov (United States)

    ... challenge to eat healthy when going to a fast food place. In general, avoiding items that are deep ... challenge to eat healthy when going to a fast food place. In general, avoiding items that are deep ...

  1. Activation of Hydrogen-Passivated Mg in GaN-Based Light Emitting Diode Annealing with Minority-Carrier Injection

    Institute of Scientific and Technical Information of China (English)

    YANG Ling; HAO Yue; LI Pei-Xian; ZHOU Xiao-Wei

    2009-01-01

    We discuss an issue on the activation of p-GaN material under different annealing conditions and study the mechanism for the p-GaN activation. Under annealing in nitrogen, it is found that hydrogen cannot be completely removed from p-GaN. The experiments also indicate that rudimental hydrogen can exist stably in a certain state where hydrogen does not passivate the Mg acceptor in the sample annealing under bias. However, making additional annealing in nitrogen, we find that the steady state hydrogen can be decomposed and the Mg-H complex could generate again. Hydrogen remaining in the layer seems to play a major role in this reversible phenomenon.

  2. Si上GaN研究

    Institute of Scientific and Technical Information of China (English)

    陈裕权

    2004-01-01

    <正> 亚琛电磁研究所订购了一台Aixtron公司的AIX200/4 RF—S设备。这台设备将用来研究基于Si衬底的GaN淀积。预计低成本的Si衬底与GaN结构相结合会大大影响未来高功率RF器件的价格。亚琛电磁研究所将用AIX 200/4 RF—S设备淀积高品质的AlGaN/GaN层和器件

  3. Is fast food addictive?

    Science.gov (United States)

    Garber, Andrea K; Lustig, Robert H

    2011-09-01

    Studies of food addiction have focused on highly palatable foods. While fast food falls squarely into that category, it has several other attributes that may increase its salience. This review examines whether the nutrients present in fast food, the characteristics of fast food consumers or the presentation and packaging of fast food may encourage substance dependence, as defined by the American Psychiatric Association. The majority of fast food meals are accompanied by a soda, which increases the sugar content 10-fold. Sugar addiction, including tolerance and withdrawal, has been demonstrated in rodents but not humans. Caffeine is a "model" substance of dependence; coffee drinks are driving the recent increase in fast food sales. Limited evidence suggests that the high fat and salt content of fast food may increase addictive potential. Fast food restaurants cluster in poorer neighborhoods and obese adults eat more fast food than those who are normal weight. Obesity is characterized by resistance to insulin, leptin and other hormonal signals that would normally control appetite and limit reward. Neuroimaging studies in obese subjects provide evidence of altered reward and tolerance. Once obese, many individuals meet criteria for psychological dependence. Stress and dieting may sensitize an individual to reward. Finally, fast food advertisements, restaurants and menus all provide environmental cues that may trigger addictive overeating. While the concept of fast food addiction remains to be proven, these findings support the role of fast food as a potentially addictive substance that is most likely to create dependence in vulnerable populations.

  4. High breakdown voltage in AlGaN/GaN HEMTs using AlGaN/GaN/AlGaN quantum-well electron-blocking layers.

    Science.gov (United States)

    Lee, Ya-Ju; Yao, Yung-Chi; Huang, Chun-Ying; Lin, Tai-Yuan; Cheng, Li-Lien; Liu, Ching-Yun; Wang, Mei-Tan; Hwang, Jung-Min

    2014-01-01

    In this paper, we numerically study an enhancement of breakdown voltage in AlGaN/GaN high-electron-mobility transistors (HEMTs) by using the AlGaN/GaN/AlGaN quantum-well (QW) electron-blocking layer (EBL) structure. This concept is based on the superior confinement of two-dimensional electron gases (2-DEGs) provided by the QW EBL, resulting in a significant improvement of breakdown voltage and a remarkable suppression of spilling electrons. The electron mobility of 2-DEG is hence enhanced as well. The dependence of thickness and composition of QW EBL on the device breakdown is also evaluated and discussed.

  5. Decomposing variation in dairy profitability: the impact of output, inputs, prices, labour and management.

    Science.gov (United States)

    Wilson, P

    2011-08-01

    The UK dairy sector has undergone considerable structural change in recent years, with a decrease in the number of producers accompanied by an increased average herd size and increased concentrate use and milk yields. One of the key drivers to producers remaining in the industry is the profitability of their herds. The current paper adopts a holistic approach to decomposing the variation in dairy profitability through an analysis of net margin data explained by physical input-output measures, milk price variation, labour utilization and managerial behaviours and characteristics. Data are drawn from the Farm Business Survey (FBS) for England in 2007/08 for 228 dairy enterprises. Average yields are 7100 litres/cow/yr, from a herd size of 110 cows that use 0·56 forage ha/cow/yr and 43·2 labour h/cow/yr. An average milk price of 22·57 pence per litre (ppl) produced milk output of £1602/cow/yr, which after accounting for calf sales, herd replacements and quota leasing costs, gave an average dairy output of £1516/cow/yr. After total costs of £1464/cow/yr this left an economic return of £52/cow/yr (0·73 ppl) net margin profit. There is wide variation in performance, with the most profitable (as measured by net margin per cow) quartile of producers achieving 2000 litres/cow/yr more than the least profitable quartile, returning a net margin of £335/cow/yr compared to a loss of £361/cow/yr for the least profitable. The most profitable producers operate larger, higher yielding herds and achieve a greater milk price for their output. In addition, a significantly greater number of the most profitable producers undertake financial benchmarking within their businesses and operate specialist dairy farms. When examining the full data set, the most profitable enterprises included significantly greater numbers of organic producers. The most profitable tend to have a greater reliance on independent technical advice, but this finding is not statistically significant

  6. Robust AlGaN/GaN MMIC Receiver Components

    NARCIS (Netherlands)

    Heijningen, M. van; Janssen, J.P.B.; Vliet, F.E. van

    2009-01-01

    Apart from delivering very high output powers, GaN can also be used to realize robust receiver components, such as Low Noise Amplifiersand Switches. This paper presents the designand measurement results of two GaN X-band switch and LNA MMICs, designed for integration in a radar front end. The switch

  7. Evaluation on the decomposability of tropical forest peat soils after conversion to an oil palm plantation.

    Science.gov (United States)

    Sangok, Faustina E; Maie, Nagamitsu; Melling, Lulie; Watanabe, Akira

    2017-06-01

    To understand the variations in the decomposability of tropical peat soil following deforestation for an oil palm plantation, a field incubation experiment was conducted in Sarawak, Malaysia. Peat soils collected from three types of primary forest, namely Mixed Peat Swamp (MPS; Gonystylus-Dactylocladus-Neoscrotechinia association), Alan Batu (ABt; Shorea albida-Gonstylus-Strenonurus association), and Alan Bunga (ABg; Shorea albida association), were packed in polyvinyl chloride pipes and installed in an oil palm plantation. Carbon dioxide (CO2) and methane (CH4) fluxes from soil were monthly measured for 3years. Environmental variables including soil temperature, soil moisture content, and groundwater table were also monitored. The pH, loss on ignition, and total carbon (C) content were similar among the three soils, while total N content was larger in the MPS than in the ABg soils. Based on (13)C nuclear magnetic resonance (NMR) spectroscopy, C composition of the MPS and ABg soils was characterized by the largest proportion of C present as alkyl C and O-alkyl C, respectively. The C composition of the ABt soil was intermediate between the MPS and ABg soils. The CO2 fluxes from the three soils ranged from 78 to 625mgCm(-2)h(-1) with a negative correlation to groundwater level. The CH4 fluxes ranged from -67 to 653μgCm(-2)h(-1). Both total CO2 and CH4 fluxes were larger in the order ABg>ABt>MPS (P<0.05). Annual rate of peat decomposition as was estimated from cumulative C loss differed up to 2 times, and the rate constant in exponential decay model was 0.033y(-1) for the MPS soil and 0.066y(-1) for the ABg soil. The field incubation results of the three forest peat soils seem to reflect the difference in the labile organic matter content, represented by polysaccharides.

  8. Time-dependent VOC-profile of decomposed human and animal remains in laboratory environment.

    Science.gov (United States)

    Rosier, E; Loix, S; Develter, W; Van de Voorde, W; Tytgat, J; Cuypers, E

    2016-09-01

    A validated method using a thermal desorber combined with a gas chromatograph coupled to a mass spectrometer was used to identify the volatile organic compounds released in decomposed human and animal remains after 9 and 12 months in glass jars in a laboratory environment. This is a follow-up study on a previous report where the first 6 months of decomposition of 6 human and 26 animal remains was investigated. In the first report, out of 452 identified compounds, a combination of 8 compounds was proposed as human and pig specific. The goal of the current study was to investigate if these 8 compounds were still released after 9 and 12 months. The next results were noticed: 287 compounds were identified; only 9 new compounds were detected and 173 were no longer seen. Sulfur-containing compounds were less prevalent as compared to the first month of decomposition. The appearance of nitrogen-containing compounds and alcohols was increasingly evident during the first 6 months, and the same trend was seen in the following 6 months. Esters became less important after 6 months. From the proposed human and pig specific compounds, diethyl disulfide was only detected during the first months of decomposition. Interestingly, the 4 proposed human and pig specific esters, as well as pyridine, 3-methylthio-1-propanol and methyl(methylthio)ethyl disulfide were still present after 9 and 12 months of decomposition. This means that these 7 human and pig specific markers can be used in the development of training aids for cadaver dogs during the whole decomposition process. Diethyl disulfide can be used in training aids for the first month of decomposition. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Decomposing the effects of children's health on mother's labor supply: is it time or money?

    Science.gov (United States)

    Gould, Elise

    2004-06-01

    In this paper, I explore how children's health influences the wages and work hours of their mother. Some children have illnesses that require expensive medicine or treatment, but demand little parental time. Others require extraordinary amounts of time; and still others require care at unpredictable times of the day. I construct a theoretical model of mother's labor supply that explicitly incorporates the financial and time costs associated with the presence of unhealthy children. The model predicts that children with time-intensive illnesses and those with unpredictable illnesses negatively influence mother's labor supply, whereas children with illnesses with a strong financial component have a positive effect on mother's labor supply. In order to empirically test this, I organize a focus group of doctors to categorize illnesses and disabilities by the type of resources they require. Using the 1997 PSID Child Development Supplement, I estimate the effects of these requirements on mother's decision to work and work hours. After controlling for the financial burden of the illness, single mothers work fewer hours if their child has a time-intensive illness and married mothers are less likely to work and work fewer hours if their child has a severe condition with an unpredictable time component. These findings are consistent with the theoretical model and highlight the need to decompose the effects of child health on mother's work status. Model specifications that aggregate across illnesses are incapable of disentangling these effects and may therefore underestimate the welfare costs of having a sick child in the family. Copyright 2004 John Wiley & Sons, Ltd.

  10. Forest Gaps Alter the Total Phenol Dynamics in Decomposing Litter in an Alpine Fir Forest.

    Science.gov (United States)

    Li, Han; Xu, Liya; Wu, Fuzhong; Yang, Wanqin; Ni, Xiangyin; He, Jie; Tan, Bo; Hu, Yi

    2016-01-01

    The total phenol content in decomposing litter not only acts as a crucial litter quality indicator, but is also closely related to litter humification due to its tight absorption to clay particles. However, limited attention has been focused on the total phenol dynamics in foliar litter in relation to forest gaps. Here, the foliar litter of six representative tree species was incubated on the forest floor from the gap center to the closed canopy of an alpine Minjiang fir (Abies faxoniana) forest in the upper reaches of the Yangtze River and eastern Tibetan Plateau. The dynamics of total phenol concentration in the incubated litter was measured from November 2012 to October 2014. Over two-year incubation, 78.22% to 94.06% of total phenols were lost from the foliar litter, but 52.08% to 86.41% of this occurred in the first year. Forest gaps accelerated the loss of total phenols in the foliar litter in the winter, although they inhibited the loss of total phenols during the growing season in the first year. In comparison with the effects of forest gaps, the variations of litter quality among different species were much stronger on the dynamics of total phenols in the second year. Overall, the loss of total phenols in the foliar litter was slightly higher in both the canopy gap and the expanded gap than in the gap center and under the closed canopy. The results suggest that the predicted decline in snow cover resulting from winter warming or vanishing gaps caused by forest regeneration will retard the loss of total phenol content in the foliar litter of alpine forest ecosystems, especially in the first decomposition year.

  11. Clostridium algifaecis sp. nov., an anaerobic bacterial species from decomposing algal scum.

    Science.gov (United States)

    Wu, Yu-Fan; Zheng, Hui; Wu, Qing-Long; Yang, Hong; Liu, Shuang-Jiang

    2014-11-01

    Two anaerobic bacterial strains, MB9-7(T) and MB9-9, were isolated from decomposing algal scum and were characterized using a polyphasic approach. Phylogenetic analysis of 16S rRNA gene sequences showed that strains MB9-7(T) and MB9-9 are closely related to each other (99.7% similarity) and they are also closely related to Clostridium tyrobutyricum (96.5%). The two strains were Gram-stain positive and rod-shaped. Growth occurred at 20-45 °C, at pH 4.0-8.0 and at NaCl concentrations of up to 2% (w/v). Acid was produced from glucose, xylose and mannose. Products of fermentation in PYG medium were mainly butyrate, acetate, carbon dioxide and hydrogen. The predominant cellular fatty acids were C(14:0) and C(16:0). The cellular polar lipids comprised phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, two glycolipids, one phospholipid, one aminophospholipid and two aminolipids. The DNA G+C contents of strain MB9-7(T) and MB9-9 were 27.9 and 28.7 mol%, respectively. These results support the assignment of the new isolates to the genus Clostridium and also distinguish them from other species of the genus Clostridium. Hence, it is proposed that strains MB9-7(T) and MB9-9 represent a novel species of the genus Clostridium, with the suggested name Clostridium algifaecis sp. nov. The type strain is MB9-7(T) ( =CGMCC 1.5188(T) =DSM 28783(T)).

  12. Functional and Structural Succession of Soil Microbial Communities below Decomposing Human Cadavers.

    Directory of Open Access Journals (Sweden)

    Kelly L Cobaugh

    Full Text Available The ecological succession of microbes during cadaver decomposition has garnered interest in both basic and applied research contexts (e.g. community assembly and dynamics; forensic indicator of time since death. Yet current understanding of microbial ecology during decomposition is almost entirely based on plant litter. We know very little about microbes recycling carcass-derived organic matter despite the unique decomposition processes. Our objective was to quantify the taxonomic and functional succession of microbial populations in soils below decomposing cadavers, testing the hypotheses that a periods of increased activity during decomposition are associated with particular taxa; and b human-associated taxa are introduced to soils, but do not persist outside their host. We collected soils from beneath four cadavers throughout decomposition, and analyzed soil chemistry, microbial activity and bacterial community structure. As expected, decomposition resulted in pulses of soil C and nutrients (particularly ammonia and stimulated microbial activity. There was no change in total bacterial abundances, however we observed distinct changes in both function and community composition. During active decay (7 - 12 days postmortem, respiration and biomass production rates were high: the community was dominated by Proteobacteria (increased from 15.0 to 26.1% relative abundance and Firmicutes (increased from 1.0 to 29.0%, with reduced Acidobacteria abundances (decreased from 30.4 to 9.8%. Once decay rates slowed (10 - 23 d postmortem, respiration was elevated, but biomass production rates dropped dramatically; this community with low growth efficiency was dominated by Firmicutes (increased to 50.9% and other anaerobic taxa. Human-associated bacteria, including the obligately anaerobic Bacteroides, were detected at high concentrations in soil throughout decomposition, up to 198 d postmortem. Our results revealed the pattern of functional and compositional

  13. Sensitivity of laccase activity to the fungicide tebuconazole in decomposing litter.

    Science.gov (United States)

    Artigas, J; Rossi, F; Gerphagnon, M; Mallet, C

    2017-04-15

    The present study investigates the sensitivity of laccase activity to the fungicide tebuconazole (TBZ) in order to seek for new functional toxicity descriptors in aquatic microbial communities associated to decomposing litter. With this aim, we analyzed the sensitivity of laccase from the different microbial components (fungi and bacteria growing separately and in co-existence), as well as that of their corresponding enzyme fractions (cell bound and diffusible), forming microbial communities in Alnus glutinosa leaves. Results show that fungi are pivotal for laccase activity in leaves and that their activity is repressed when they co-exist with bacteria. The sensitivity of laccase activity to the TBZ was only detectable in leaves colonized by fungi separately (Alatospora acuminata populations), but absent in those colonized by bacteria separately and/or mixed fungi plus bacteria. Specifically, the increase of TBZ concentration enhances laccase activity in Alatospora acuminata populations but decreases ergosterol concentration as well as the amount of 18S RNA gene copies. This activity response suggests a detoxification mechanism employed by the fungus in order to reduce TBZ toxicity. Besides, enzyme fractioning showed that laccase activity in the cell bound fraction (76% of the total activity) was sensitive to the fungicide, but not that in the diffusible fraction (24% of total activity). Hence, TBZ would influence laccase activity in the presence of fungal cells but not in enzymes already synthesized in the extracellular space. The present study highlights the importance of the biological complexity level (i. e. population, community, ecosystem) when seeking for appropriate functional ecotoxicity descriptors in aquatic microbial communities. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Effect of alginic acid decomposing bacterium on the growth of Laminaria japonica (Phaeophyceae)

    Institute of Scientific and Technical Information of China (English)

    WANG You; TANG Xue-xi; YANG Zhen; YU Zhi-ming

    2006-01-01

    We collected the diseased blades of Laminaria japonica from Yantai Sea Farm from October to December 2002, and the alginic acid decomposing bacterium on the diseased blade was isolated and purified, and was identified as Alteromonas espejiana. This bacterium was applied as the causative pathogen to infect the blades of L. japonica under laboratory conditions. The aim of the present study was to identify the effects of the bacterium on the growth of L. japonica, and to find the possibly effective mechanism. Results showed that: (1)The blades of L.japonica exhibited symptoms of lesion,bleaching and deterioration when infected by the bacterium,and their growth and photosynthesis were dramatically suppressed. At the same time, the reactive oxygen species (ROS) generation enhanced obviously, and the relative membrane permeability increased significantly. The contents of malonaldehyde (MDA) and free fatty acid in the microsomol membrane greatly elevated, but the phospholipid content decreased. Result suggested an obvious peroxidation and deesterrification in the blades of L. japonica when infected by the bacterium. (2) The simultaneous assay on the antioxidant enzyme activities demonstrated that superoxide dismutase (SOD) and catalase (CAT) increased greatly when infected by the bacterium, but glutathione peroxidase (Gpx) and ascorbate peroxidase (APX) did not exhibit active responses to the bacterium throughout the experiment. (3) The histomorphological observations gave a distinctive evidence of the severity of the lesions as well as the relative abundance in the bacterial population on the blades after infection. The bacterium firstly invaded into the endodermis of L. japonica and gathered around there, and then resulted in the membrane damage, cells corruption and ultimately, the death of L.japonica.

  15. Litter dynamics in two Sierran mixed conifer forests. II. Nutrient release in decomposing leaf litter

    Science.gov (United States)

    Stohlgren, Thomas J.

    1988-01-01

    The factors influencing leaf litter decomposition and nutrient release patterns were investigated for 3.6 years in two mixed conifer forests in the southern Sierra Nevada of California. The giant sequoia–fir forest was dominated by giant sequoia (Sequoiadendrongiganteum (Lindl.) Buchh.), white fir (Abiesconcolor Lindl. & Gord.), and sugar pine (Pinuslambertiana Dougl.). The fir–pine forest was dominated by white fir, sugar pine, and incense cedar (Calocedrusdecurrens (Torr.) Florin). Initial concentrations of nutrients and percent lignin, cellulose, and acid detergent fiber vary considerably in freshly abscised leaf litter of the studied species. Giant sequoia had the highest concentration of lignin (20.3%) and the lowest concentration of nitrogen (0.52%), while incense cedar had the lowest concentration of lignin (9.6%) and second lowest concentration of nitrogen (0.63%). Long-term (3.6 years) foliage decomposition rates were best correlated with initial lignin/N (r2 = 0.94, p r2 = 0.92, p r2 = 0.80, p incense cedar immobilized N and to a lesser extent P, while sugar pine immobilized Ca. Strong linear or negative exponential relationships existed between initial concentrations of N, P, K, and Ca and percent original mass remaining of those nutrients after 3.6 years. This suggests efficient retention of these nutrients in the litter layer of these ecosystems. Nitrogen concentrations steadily increase in decomposing leaf litter, effectively reducing the C/N ratios from an initial range of 68–96 to 27–45 after 3.6 years.

  16. Seasonal Variability May Affect Microbial Decomposers and Leaf Decomposition More Than Warming in Streams.

    Science.gov (United States)

    Duarte, Sofia; Cássio, Fernanda; Ferreira, Verónica; Canhoto, Cristina; Pascoal, Cláudia

    2016-08-01

    Ongoing climate change is expected to affect the diversity and activity of aquatic microbes, which play a key role in plant litter decomposition in forest streams. We used a before-after control-impact (BACI) design to study the effects of warming on a forest stream reach. The stream reach was divided by a longitudinal barrier, and during 1 year (ambient year) both stream halves were at ambient temperature, while in the second year (warmed year) the temperature in one stream half was increased by ca. 3 °C above ambient temperature (experimental half). Fine-mesh bags containing oak (Quercus robur L.) leaves were immersed in both stream halves for up to 60 days in spring and autumn of the ambient and warmed years. We assessed leaf-associated microbial diversity by denaturing gradient gel electrophoresis and identification of fungal conidial morphotypes and microbial activity by quantifying leaf mass loss and productivity of fungi and bacteria. In the ambient year, no differences were found in leaf decomposition rates and microbial productivities either between seasons or stream halves. In the warmed year, phosphorus concentration in the stream water, leaf decomposition rates, and productivity of bacteria were higher in spring than in autumn. They did not differ between stream halves, except for leaf decomposition, which was higher in the experimental half in spring. Fungal and bacterial communities differed between seasons in both years. Seasonal changes in stream water variables had a greater impact on the activity and diversity of microbial decomposers than a warming regime simulating a predicted global warming scenario.

  17. Decomposing metaphor processing at the cognitive and neural level through functional magnetic resonance imaging.

    Science.gov (United States)

    Bambini, Valentina; Gentili, Claudio; Ricciardi, Emiliano; Bertinetto, Pier Marco; Pietrini, Pietro

    2011-10-10

    Prior neuroimaging studies on metaphor comprehension have tended to focus on the role of the right hemisphere, without reaching consensus and leaving aside the functional architecture of this process. The present work aimed to break down metaphor comprehension into its functional components. The study rationale is two-fold: on the one hand, the large-scale network model as emerging in cognitive neuroscience led us to a consideration of metaphor as supported by a distributed and bilateral network; on the other hand, we based on the accounts of figurative language put forward in pragmatics and cognitive science to postulate a decomposition of such a network into multiple sub-systems. During scanning, participants implicitly processed metaphorical (familiar and unfamiliar) and non-metaphorical passages, while being explicitly involved in an adjective matching task to be performed after reading the target passages. Several regions showed greater activity to metaphors as compared to non-metaphors, including left and right inferior frontal gyrus, right superior temporal gyrus, left angular gyrus, and anterior cingulate. This pattern of activations, markedly bilateral, can be decomposed into circumscribed functional sub-systems mediating different aspects of metaphor resolution, as foreseen in the pragmatic and cognitive literature: (a) the conceptual/pragmatic machinery in the bilateral inferior frontal gyrus and in the left angular gyrus, which supports the integration of linguistic material and world knowledge in context; (b) the attentional component in the anterior cingulate and prefrontal areas, which is set to monitor and filter for the relevant aspects of context and for the appropriate meanings; (c) the Theory of Mind system along the right superior temporal sulcus, which deals with the recognition of speakers' communicative intentions and is more extensively activated by unfamiliar metaphors. The results have several implications for the field of neuropragmatics

  18. Functional and Structural Succession of Soil Microbial Communities below Decomposing Human Cadavers

    Science.gov (United States)

    Cobaugh, Kelly L.; Schaeffer, Sean M.; DeBruyn, Jennifer M.

    2015-01-01

    The ecological succession of microbes during cadaver decomposition has garnered interest in both basic and applied research contexts (e.g. community assembly and dynamics; forensic indicator of time since death). Yet current understanding of microbial ecology during decomposition is almost entirely based on plant litter. We know very little about microbes recycling carcass-derived organic matter despite the unique decomposition processes. Our objective was to quantify the taxonomic and functional succession of microbial populations in soils below decomposing cadavers, testing the hypotheses that a) periods of increased activity during decomposition are associated with particular taxa; and b) human-associated taxa are introduced to soils, but do not persist outside their host. We collected soils from beneath four cadavers throughout decomposition, and analyzed soil chemistry, microbial activity and bacterial community structure. As expected, decomposition resulted in pulses of soil C and nutrients (particularly ammonia) and stimulated microbial activity. There was no change in total bacterial abundances, however we observed distinct changes in both function and community composition. During active decay (7 - 12 days postmortem), respiration and biomass production rates were high: the community was dominated by Proteobacteria (increased from 15.0 to 26.1% relative abundance) and Firmicutes (increased from 1.0 to 29.0%), with reduced Acidobacteria abundances (decreased from 30.4 to 9.8%). Once decay rates slowed (10 - 23 d postmortem), respiration was elevated, but biomass production rates dropped dramatically; this community with low growth efficiency was dominated by Firmicutes (increased to 50.9%) and other anaerobic taxa. Human-associated bacteria, including the obligately anaerobic Bacteroides, were detected at high concentrations in soil throughout decomposition, up to 198 d postmortem. Our results revealed the pattern of functional and compositional succession

  19. Antisites and anisotropic diffusion in GaAs and GaSb

    KAUST Repository

    Tahini, H. A.

    2013-10-02

    The significant diffusion of Ga under Ga-rich conditions in GaAs and GaSb is counter intuitive as the concentration of Ga vacancies should be depressed although Ga vacancies are necessary to interpret the experimental evidence for Ga transport. To reconcile the existence of Ga vacancies under Ga-rich conditions, transformation reactions have been proposed. Here, density functional theory is employed to calculate the formation energies of vacancies on both sublattices and the migration energy barriers to overcome the formation of the vacancy-antisite defect. Transformation reactions enhance the vacancy concentration in both materials and migration energy barriers indicate that Ga vacancies will dominate.

  20. Optical properties and band bending of InGaAs/GaAsBi/InGaAs type-II quantum well grown by gas source molecular beam epitaxy

    Science.gov (United States)

    Pan, Wenwu; Zhang, Liyao; Zhu, Liang; Li, Yaoyao; Chen, Xiren; Wu, Xiaoyan; Zhang, Fan; Shao, Jun; Wang, Shumin

    2016-09-01

    Photoluminescence (PL) properties of In0.2Ga0.8As/GaAs0.96Bi0.04/In0.2Ga0.8As quantum well (QW) grown on GaAs substrates by gas source molecular beam epitaxy were studied by varying excitation power and temperature, respectively. The type-II transition energy shifts from 1.149 eV to 1.192 eV when increasing the excitation power from 10 mW to 150 mW at 4.5 K, which was ascribed to the band-bending effect. On the other hand, the type-II PL quenches quickly along with fast redshift with the increasing temperature due to the relaxation of the band bending caused by the thermal excitation process. An 8 band k.p model was used to analyze the electronic properties and the band-bending effect in the type-II QW. The calculated subband levels and transition energy fit well with the experiment results, and two thermal activation energies of 8.7 meV and 50 meV, respectively, are deduced.

  1. Ramadan, fasting and pregnancy

    DEFF Research Database (Denmark)

    Ahmed, Urfan Zahoor; Lykke, Jacob Alexander

    2014-01-01

    In Islam, the month of Ramadan is a period of fasting lasting 29 or 30 days. Epidemiological studies among Muslims in Denmark have not been conducted, but studies show, that fasting among pregnant Muslim women is common. Fasting does not increase the risk of growth restriction or preterm delivery......, but there are reports of decreased foetal movements. Furthermore, the fasting may have long-term health consequences for the offspring, especially when they reach their middle age. According to Islam and the interpretation, pregnant and breast-feeding women are allowed to postpone the fasting of the month of Ramadan...

  2. DLTS measurements on GaSb/GaAs quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Hoegner, Annika; Nowozin, Tobias; Marent, Andreas; Bimberg, Dieter [Institut fuer Festkoerperphysik, TU Berlin (Germany); Tseng, Chi-Che [Institute of Photonics Technologies, NTHU (China); Lin, Shih-Yen [Institute of Optoelectronic Sciences, NTOU (China)

    2010-07-01

    Memory devices based on hole storage in self-organized quantum dots offer significant advantages with respect to storage time and scalability. Recently, we demonstrated a first prototype based on InAs/GaAs quantum dots at low temperatures. To enable feasible storage times at room temperature the localisation energy of the quantum dots has to be increased by using other material systems. A first step in this direction is the use of GaSb quantum dots within a GaAs matrix. We have characterized self-organized GaSb/GaAs quantum dots embedded into a n{sup +}p-diode structure. DLTS measurements on hole emission were conducted and yield a strong peak from which a mean emission energy of about 400 meV can be extracted. The reference sample without the quantum dots (containing only the wetting layer) shows no such peak.

  3. Growth and Optimization of 2 Micrometers InGaSb/AlGaSb Quantum-Well-Based VECSELs on GaAs/AlGaAs DBRs

    Science.gov (United States)

    2013-08-01

    optically pumped vertical-external-cavity surface-emitting lasers (VECSELs) based on InGaSb/AlGaSb quantum wells grown on GaAs/ AlGaAs distributed Bragg...cross-sectional transmission electron microscopy. The optical properties of the III-Sb active regions are characterized by time-resolved... optically pumped vertical- external-cavity surface-emitting lasers (VECSELs) based on InGaSb/AlGaSb quantum wells grown on GaAs/ AlGaAs distri- buted Bragg

  4. Effect of GaN buffer polarization on electron distribution of AlGaN/GaN heterostructure

    Energy Technology Data Exchange (ETDEWEB)

    He, Xiaoguang; Zhao, Degang, E-mail: dgzhao@red.semi.ac.cn; Liu, Wei; Yang, Jing; Li, Xiaojing; Li, Xiang

    2016-06-15

    The formation of 2DEG in AlGaN/GaN heterostructure is discussed in detail. A misunderstanding about the 2DEG sheet density expression is clarified. It is predicted by theoretical analysis and validated by self-consistent Schrodinger–Poisson numerical simulation that under the force of GaN polarization, large amounts of electrons will accumulate at the GaN/substrate interface in AlGaN/GaN/substrate HEMT structure. - Highlights: • The formation of 2DEG in AlGaN/GaN heterostructure is discussed in detail. • Self-consistent Schrodinger–Poisson numerical simulation is used to modulate the AlGaN/GaN/substrate structure. • It is predicted by that large amounts of electrons will accumulate at the GaN/substrate interface.

  5. Integrative Physiology of Fasting.

    Science.gov (United States)

    Secor, Stephen M; Carey, Hannah V

    2016-03-15

    Extended bouts of fasting are ingrained in the ecology of many organisms, characterizing aspects of reproduction, development, hibernation, estivation, migration, and infrequent feeding habits. The challenge of long fasting episodes is the need to maintain physiological homeostasis while relying solely on endogenous resources. To meet that challenge, animals utilize an integrated repertoire of behavioral, physiological, and biochemical responses that reduce metabolic rates, maintain tissue structure and function, and thus enhance survival. We have synthesized in this review the integrative physiological, morphological, and biochemical responses, and their stages, that characterize natural fasting bouts. Underlying the capacity to survive extended fasts are behaviors and mechanisms that reduce metabolic expenditure and shift the dependency to lipid utilization. Hormonal regulation and immune capacity are altered by fasting; hormones that trigger digestion, elevate metabolism, and support immune performance become depressed, whereas hormones that enhance the utilization of endogenous substrates are elevated. The negative energy budget that accompanies fasting leads to the loss of body mass as fat stores are depleted and tissues undergo atrophy (i.e., loss of mass). Absolute rates of body mass loss scale allometrically among vertebrates. Tissues and organs vary in the degree of atrophy and downregulation of function, depending on the degree to which they are used during the fast. Fasting affects the population dynamics and activities of the gut microbiota, an interplay that impacts the host's fasting biology. Fasting-induced gene expression programs underlie the broad spectrum of integrated physiological mechanisms responsible for an animal's ability to survive long episodes of natural fasting.

  6. Ivestigation of an InGaN - GaN nanowire heterstructure

    Energy Technology Data Exchange (ETDEWEB)

    Limbach, Friederich; Gotschke, Tobias; Stoica, Toma; Calarco, Raffaella; Gruetzmacher, Detlev [Institute of Bio- and Nanosystems (IBN-1), Research Center Juelich GmbH, Juelich (Germany); JARA-Fundamentals of Future Information Technology, Juelich (Germany); Sutter, Eli; Ciston, Jim [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY (United States); Cusco, Ramon; Artus, Luis [Institut Jaume Almera, Consell Superior d' Investigacions Cientifiques (CSIC), Barcelona, Catalonia (Spain); Kremling, Stefan; Hoefling, Sven; Worschech, Lukas [University Wurzburg, Wilhelm Conrad Rontgen Research Centre Complex Matter Systems, Wuerzburg (Germany)

    2011-07-01

    InGaN/GaN nanowire (NW) heterostructures grown by molecular beam epitaxy were studied in comparison to their GaN and InGaN counterparts. The InGaN/GaN heterostructure NWs are composed of a GaN NW, a thin InGaN shell, and a multi-faceted InGaN cap wrapping the top part of the GaN NW. Transmission electron microscopy images taken from different parts of a InGaN/GaN nanowire show a wurtzite structure of the GaN core and the epitaxial InGaN shell around it. Photoluminescence spectra of these heterostructure NW ensembles show an emission peak at 2.1 eV. However, {mu}-PL spectra measured on single nanowires reveal much sharper luminescence peaks. A Raman analysis reveals a variation of the In content between 20 % and 30 %, in agreement with PL and TEM investigations.

  7. FAST User Guide

    Science.gov (United States)

    Walatka, Pamela P.; Clucas, Jean; McCabe, R. Kevin; Plessel, Todd; Potter, R.; Cooper, D. M. (Technical Monitor)

    1994-01-01

    The Flow Analysis Software Toolkit, FAST, is a software environment for visualizing data. FAST is a collection of separate programs (modules) that run simultaneously and allow the user to examine the results of numerical and experimental simulations. The user can load data files, perform calculations on the data, visualize the results of these calculations, construct scenes of 3D graphical objects, and plot, animate and record the scenes. Computational Fluid Dynamics (CFD) visualization is the primary intended use of FAST, but FAST can also assist in the analysis of other types of data. FAST combines the capabilities of such programs as PLOT3D, RIP, SURF, and GAS into one environment with modules that share data. Sharing data between modules eliminates the drudgery of transferring data between programs. All the modules in the FAST environment have a consistent, highly interactive graphical user interface. Most commands are entered by pointing and'clicking. The modular construction of FAST makes it flexible and extensible. The environment can be custom configured and new modules can be developed and added as needed. The following modules have been developed for FAST: VIEWER, FILE IO, CALCULATOR, SURFER, TOPOLOGY, PLOTTER, TITLER, TRACER, ARCGRAPH, GQ, SURFERU, SHOTET, and ISOLEVU. A utility is also included to make the inclusion of user defined modules in the FAST environment easy. The VIEWER module is the central control for the FAST environment. From VIEWER, the user can-change object attributes, interactively position objects in three-dimensional space, define and save scenes, create animations, spawn new FAST modules, add additional view windows, and save and execute command scripts. The FAST User Guide uses text and FAST MAPS (graphical representations of the entire user interface) to guide the user through the use of FAST. Chapters include: Maps, Overview, Tips, Getting Started Tutorial, a separate chapter for each module, file formats, and system

  8. Spectroscopy of GaAs quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    West, L.C.

    1985-07-01

    A new type of optical dipole transition in GaAs quantum wells has been observed. The dipole occurs between two envelope states of the conduction band electron wavefunction, and is called a quantum well envelope state transition (QWEST). The QWEST is observed by infrared absorption in three different samples with quantum well thicknesses 65, 82, and 92 A and resonant energies of 152, 121, and 108 MeV, respectively. The oscillator strength is found to have values of over 12, in good agreement with prediction. The linewidths are seen as narrow as 10 MeV at room temperature and 7 MeV at low temperature, thus proving a narrow line resonance can indeed occur between transitions of free electrons. Techniques for the proper growth of these quantum well samples to enable observation of the QWEST have also been found using (AlGa)As compounds. This QWEST is considered to be an ideal material for an all optical digital computer. The QWEST can be made frequency matched to the inexpensive Carbon Dioxide laser with an infrared wavelength of 10 microns. The nonlinearity and fast relaxation time of the QWEST indicate a logic element with a subpicosecond switch time can be built in the near future, with a power level which will eventually be limited only by the noise from a lack of quanta to above approximately 10 microwatts. 64 refs., 35 figs., 6 tabs.

  9. Prostatic uptake of Ga-67

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, W.T.; Rosen, P.R.; Weiland, F.L.; Ritchey, M.L.

    1984-08-01

    Midline activity low in the pelvis seen on Ga-67 scans is frequently attributed to colonic excretion of radionuclide. Two cases of infectious prostatitis with focal uptake of Ga-67 within the prostate gland are described. A technique of using limited quantities of barium administered by enema and appropriate positional imaging, which localized pelvic activity to the prostate, is described.

  10. Wastes disposal on board a ship. Apparatus to decompose and annihilate wet refuses bionically; Senjo no haikibutsu shori. Namagomi no bio bunkai shometsuki

    Energy Technology Data Exchange (ETDEWEB)

    Takenaka, S.

    1996-07-25

    A bionic refuse disposing and annihilating apparatus for wet refuses produced on board a ship was developed, and introduced in this paper. This apparatus uses a system that biomass as a decomposing medium is maintained dry in a disposal tank, and wet refuses are decomposed and annihilated by the biomass working only with water contained in the wet refuses themselves. The system uses a decomposing medium composed of a mixture of different kinds of organic matters mixed with various nutrients, and automatically controls absorption and exhalation of decomposing water without using a heater. Almost all of wet refuses decomposes and annihilates in twelve hours after having been charged in their original forms. The decomposing medium can be used continuously for six months to a year. Because of complete annihilation by the bionic effect, no residue is created. This system uses a normal-temperature decomposing and annihilating bionic technology, whose minimum temperature required for decomposition and annihilation is 10{degree}C or higher, and the highest permissible temperature is 75{degree}C. Dry and cool environment at about 20{degree}C is most suitable. Deodorizing function of the biomass itself as the decomposing medium suppresses odor generation. 3 figs.

  11. FastPM: a new scheme for fast simulations of dark matter and halos

    CERN Document Server

    Feng, Yu; Seljak, Uros

    2016-01-01

    We introduce FastPM, a highly-scalable approximated particle mesh N-body solver, which implements the particle mesh (PM) scheme enforcing correct linear evolution via a cheap low resolution broadband correction at each time step. Employing a 2-dimensional domain decomposing scheme, FastPM scales extremely well with a very large number of CPUs. In contrast to COmoving-LAgrangian (COLA) approach, we do not require to split the force or track separately the 2LPT solution, reducing the code complexity and memory requirements. We compare FastPM with different number of steps ($N_s$) and force resolution factor ($B$) against 3 benchmarks: halo mass function from Friends of Friends halo finder, halo and dark matter power spectrum, and cross correlation coefficient (or stochasticity), relative to a high resolution TreePM simulation. We show that the broadband correction scheme reduces the halo stochasticity when compared to COLA with the same number of steps and force resolution. While increasing $N_s$ and $B$ improv...

  12. A preliminary report on the development of MATLAB tensor classes for fast algorithm prototyping.

    Energy Technology Data Exchange (ETDEWEB)

    Bader, Brett William; Kolda, Tamara Gibson (Sandia National Laboratories, Livermore, CA)

    2004-07-01

    We describe three MATLAB classes for manipulating tensors in order to allow fast algorithm prototyping. A tensor is a multidimensional or N-way array. We present a tensor class for manipulating tensors which allows for tensor multiplication and 'matricization.' We have further added two classes for representing tensors in decomposed format: cp{_}tensor and tucker{_}tensor. We demonstrate the use of these classes by implementing several algorithms that have appeared in the literature.

  13. Measuring and decomposing inequity in self-reported morbidity and self-assessed health in Thailand

    Directory of Open Access Journals (Sweden)

    Sidorenko Alexandra

    2007-12-01

    Full Text Available Abstract Background In recent years, interest in the study of inequalities in health has not stopped at quantifying their magnitude; explaining the sources of inequalities has also become of great importance. This paper measures socioeconomic inequalities in self-reported morbidity and self-assessed health in Thailand, and the contributions of different population subgroups to those inequalities. Methods The Health and Welfare Survey 2003 conducted by the Thai National Statistical Office with 37,202 adult respondents is used for the analysis. The health outcomes of interest derive from three self-reported morbidity and two self-assessed health questions. Socioeconomic status is measured by adult-equivalent monthly income per household member. The concentration index (CI of ill health is used as a measure of socioeconomic health inequalities, and is subsequently decomposed into contributing factors. Results The CIs reveal inequality gradients disadvantageous to the poor for both self-reported morbidity and self-assessed health in Thailand. The magnitudes of these inequalities were higher for the self-assessed health outcomes than for the self-reported morbidity outcomes. Age and sex played significant roles in accounting for the inequality in reported chronic illness (33.7 percent of the total inequality observed, hospital admission (27.8 percent, and self-assessed deterioration of health compared to a year ago (31.9 percent. The effect of being female and aged 60 years or older was by far the strongest demographic determinant of inequality across all five types of health outcome. Having a low socioeconomic status as measured by income quintile, education and work status were the main contributors disadvantaging the poor in self-rated health compared to a year ago (47.1 percent and self-assessed health compared to peers (47.4 percent. Residence in the rural Northeast and rural North were the main regional contributors to inequality in self

  14. Self-decomposable Fibrous Bridging Additives for Temporary Cementitious Fracture Sealers in EGS Wells

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Pyatina, T.; Gill, S.; Kisslinger, K.; Iverson, B.; Bour, D.

    2012-11-01

    potential as a self-decomposable bridging additive in the SSASC cement sealer.

  15. Modelling the dissipation and leaching of two herbicides in decomposing mulch of crop residues

    Science.gov (United States)

    Aslam, Sohaib; Iqbal, Akhtar; Lafolie, François; Recous, Sylvie; Benoit, Pierre; Garnier, Patricia

    2013-04-01

    greater leaching from mulch than S-metolachlor because of its lower adsorption coefficients to organic mulch. Moreover, simulated results showed a much faster degradation of glyphosate but greater non-extractable residue formation for S-metolachlor. Keywords: Mulch; Pesticides; Transport; Degradation; Modeling; Pastis-mulch References Findeling, A., Garnier, P., Coppens, F., Lafolie, F., Recous, S., 2007. Modelling water, carbon and nitrogen dynamics in soil covered with decomposing mulch. European Journal of Soil Science 58, 196-206. Lashermes, G., Zhang, Y., Houot, S., Barriuso, E., Steyer, J.P., Patureau, D., Garnier, P., 2013. A model coupling organic carbon and organic pollutant dynamics during composting. Journal of Environmental Quality. In Press.

  16. A decomposable silica-based antibacterial coating for percutaneous titanium implant

    Directory of Open Access Journals (Sweden)

    Wang J

    2017-01-01

    Full Text Available Jia Wang,1,* Guofeng Wu,2,* Xiangwei Liu,3,* Guanyang Sun,1 Dehua Li,3 Hongbo Wei3 1State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi’an, 2Department of Prosthodontics, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, 3State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Oral Implants, School of Stomatology, The Fourth Military Medical University, Xi’an, People’s Republic of China *These authors contributed equally to this work Abstract: Although percutaneous titanium implants have become one of the best choices as retainers in the facial defects, peri-implantitis still occurs at a significant rate. This unwanted complication occurs due to adhesion of bacteria and subsequent biofilm formation. To solve this problem, we have developed a novel antibiotic nanodelivery system based on self-decomposable silica nanoparticles. In this study, silica-gentamycin (SG nanoparticles were successfully fabricated using an innovative one-pot solution. The nanoparticles were incorporated within a gelatin matrix and cross-linked on microarc-oxidized titanium. To characterize the SG nanoparticles, their particle size, zeta potential, surface morphology, in vitro drug release, and decomposition process were sequentially evaluated. The antibacterial properties against the gram-positive Staphylococcus aureus, including bacterial viability, antibacterial rate, and bacteria morphology, were analyzed using SG-loaded titanium specimens. Any possible influence of released gentamycin on the viability of human fibroblasts, which are the main component of soft tissues, was investigated. SG nanoparticles from the

  17. How does litter quality and site heterogeneity interact on decomposer food webs of a semi-natural forest?

    DEFF Research Database (Denmark)

    Strandmark, Lisa Bjørnlund; Christensen, Søren

    2005-01-01

    canopies at two topographically different sites, above and below a slope, respectively, to cover variable environmental conditions. Litter was collected after 2, 4 and 9 months of decomposition. Extensive decay prevented analysis of ash after 9 months. Density of bacteria (CFU), active fungal mycelium (FDA...... in the decomposer food web, site effects were also detected and nematode functional groups responded more to site than to litter quality early on in the decomposition process.......The relative importance of litter quality and site heterogeneity on population dynamics of decomposer food webs was investigated in a semi-natural mixed deciduous forest in Denmark. Litterbags containing beech or ash leaves were placed in four plots. Plots were located within gaps and under closed...

  18. Point sets that minimize $(\\le k)$-edges, $3$-decomposable drawings, and the rectilinear crossing number of $K_{30}$

    CERN Document Server

    Cetina, M; Leaños, J; Villalobos, C

    2010-01-01

    There are two properties shared by all known crossing-minimizing geometric drawings of $K_n$, for $n$ a multiple of $3$. First, the underlying $n$-point set of these drawings has exactly $3\\binom{k+2}{2}$ $(\\le k)$-edges, for all $0\\le k < n/3$. Second, all such drawings have the $n$ points divided into three groups of equal size; this last property is captured under the concept of $3$-decomposability. In this paper we show that these properties are tightly related: every $n$-point set with exactly $3\\binom{k+2}{2}$ $(\\le k)$-edges for all $0\\le k < n/3$, is $3$-decomposable. As an application, we prove that the rectilinear crossing number of $K_{30}$ is $9726$.

  19. Distribution and enzymatic activity of heterotrophic bacteria decomposing selected macromolecular compounds in a Baltic Sea sandy beach

    Science.gov (United States)

    Podgórska, B.; Mudryk, Z. J.

    2003-03-01

    The potential capability to decompose macromolecular compounds, and the level of extracellular enzyme activities were determined in heterotrophic bacteria isolated from a sandy beach in Sopot on the Southern Baltic Sea coast. Individual isolates were capable of hydrolysing a wide spectrum of organic macromolecular compounds. Lipids, gelatine, and DNA were hydrolyzed most efficiently. Only a very small percentage of strains were able to decompose cellulose, and no pectinolytic bacteria were found. Except for starch-hydrolysis, no significant differences in the intensity of organic compound decomposition were recorded between horizontal and vertical profiles of the studied beach. Of all the studied extracellular enzymes, alkaline phosphatase, esterase lipase, and leucine acrylaminidase were most active; in contrast, the activity α-fucosidase, α-galactosidase and β-glucouronidase was the weakest. The level of extracellular enzyme activity was similar in both sand layers.

  20. Highly concentrated synthesis of copper-zinc-tin-sulfide nanocrystals with easily decomposable capping molecules for printed photovoltaic applications.

    Science.gov (United States)

    Kim, Youngwoo; Woo, Kyoohee; Kim, Inhyuk; Cho, Yong Soo; Jeong, Sunho; Moon, Jooho

    2013-11-07

    Among various candidate materials, Cu2ZnSnS4 (CZTS) is a promising earth-abundant semiconductor for low-cost thin film solar cells. We report a facile, less toxic, highly concentrated synthetic method utilizing the heretofore unrecognized, easily decomposable capping ligand of triphenylphosphate, where phase-pure, single-crystalline, and well-dispersed colloidal CZTS nanocrystals were obtained. The favorable influence of the easily decomposable capping ligand on the microstructural evolution of device-quality CZTS absorber layers was clarified based on a comparative study with commonly used oleylamine-capped CZTS nanoparticles. The resulting CZTS nanoparticles enabled us to produce a dense and crack-free absorbing layer through annealing under a N2 + H2S (4%) atmosphere, demonstrating a solar cell with an efficiency of 3.6% under AM 1.5 illumination.

  1. On the utility of the multi-level algorithm for the solution of nearly completely decomposable Markov chains

    Science.gov (United States)

    Leutenegger, Scott T.; Horton, Graham

    1994-01-01

    Recently the Multi-Level algorithm was introduced as a general purpose solver for the solution of steady state Markov chains. In this paper, we consider the performance of the Multi-Level algorithm for solving Nearly Completely Decomposable (NCD) Markov chains, for which special-purpose iteractive aggregation/disaggregation algorithms such as the Koury-McAllister-Stewart (KMS) method have been developed that can exploit the decomposability of the the Markov chain. We present experimental results indicating that the general-purpose Multi-Level algorithm is competitive, and can be significantly faster than the special-purpose KMS algorithm when Gauss-Seidel and Gaussian Elimination are used for solving the individual blocks.

  2. Technological transformation of chlorate decomposing tank%氯酸盐分解槽的工艺改造

    Institute of Scientific and Technical Information of China (English)

    封小洪; 蒲云彬

    2015-01-01

    介绍氯酸盐产生的原因及危害,分析分解槽分解效率不高的原因,给出工艺改进方案和采取的改造措施.%The formation causes and harm of chlorate were introduced. The causes of low decomposition rate of chlorate in decomposer were analyzed. Process improvement plans and reform measures taken were provided.

  3. 31% European InGaP/GaAs/InGaAs Solar Cells for Space Application

    Directory of Open Access Journals (Sweden)

    Campesato Roberta

    2017-01-01

    Full Text Available We report a triple junction InGaP/GaAs/InGaNAs solar cell with efficiency of ~31% at AM0, 25 °C fabricated using a combined molecular beam epitaxy (MBE and metal-organic chemical vapour deposition (MOCVD processes. The prototype cells comprise of InGaNAs (Indium Gallium Nitride Arsenide bottom junction grown on a GaAs (Gallium Arsenide substrate by MBE and middle and top junctions deposited by MOCVD. Repeatable cell characteristics and uniform efficiency pattern over 4-inch wafers were obtained. Combining the advantages offered by MBE and MOCVD opens a new perspective for fabrication of high-efficiency space tandem solar cells with three or more junctions. Results of radiation resistance of the sub-cells are also presented and critically evaluated to achieve high efficiency in EOL conditions.

  4. Efficient algorithms for solving the non-linear vibrational coupled-cluster equations using full and decomposed tensors.

    Science.gov (United States)

    Madsen, Niels K; Godtliebsen, Ian H; Christiansen, Ove

    2017-04-07

    Vibrational coupled-cluster (VCC) theory provides an accurate method for calculating vibrational spectra and properties of small to medium-sized molecules. Obtaining these properties requires the solution of the non-linear VCC equations which can in some cases be hard to converge depending on the molecule, the basis set, and the vibrational state in question. We present and compare a range of different algorithms for solving the VCC equations ranging from a full Newton-Raphson method to approximate quasi-Newton models using an array of different convergence-acceleration schemes. The convergence properties and computational cost of the algorithms are compared for the optimization of VCC states. This includes both simple ground-state problems and difficult excited states with strong non-linearities. Furthermore, the effects of using tensor-decomposed solution vectors and residuals are investigated and discussed. The results show that for standard ground-state calculations, the conjugate residual with optimal trial vectors algorithm has the shortest time-to-solution although the full Newton-Raphson method converges in fewer macro-iterations. Using decomposed tensors does not affect the observed convergence rates in our test calculations as long as the tensors are decomposed to sufficient accuracy.

  5. Litter type affects the activity of aerobic decomposers in a boreal peatland more than site nutrient and water level regimes

    Directory of Open Access Journals (Sweden)

    P. Straková

    2011-02-01

    Full Text Available Peatlands are carbon (C storage ecosystems sustained by a high water level (WL. High WL creates anoxic conditions that suppress the activity of aerobic decomposers and provide conditions for peat accumulation. Peatland function can be dramatically affected by WL drawdown caused by land-use and/or climate change. Aerobic decomposers are directly affected by WL drawdown through environmental factors such as increased oxygenation and nutrient availability. Additionally, they are indirectly affected via changes in plant community composition and litter quality. We studied the relative importance of direct and indirect effects of WL drawdown on aerobic decomposer activity in plant litter. We did this by profiling 11 extracellular enzymes involved in the mineralization of organic C, nitrogen, phosphorus and sulphur. Our study sites represented a three-stage chronosequence from pristine (undrained to short-term (years and long-term (decades WL drawdown conditions under two nutrient regimes. The litter types included reflected the prevalent vegetation, i.e., Sphagnum mosses, graminoids, shrubs and trees.

    WL drawdown had a direct and positive effect on microbial activity. Enzyme allocation shifted towards C acquisition, which caused an increase in the rate of decomposition. However, litter type overruled the direct effects of WL drawdown and was the main factor shaping microbial activity patterns. Our results imply that changes in plant community composition in response to persistent WL drawdown will strongly affect the C dynamics of peatlands.

  6. Effects of heat treatments on the properties of Cu(In,Ga)Se{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, SeJin; Kim, ChaeWoong; Yun, JaeHo; Lee, JeongChul; Yoon, KyungHoon [Solar Cells Research Center, Korea Institute of Energy Research, 71-2 Jang-dong, Yuseong-gu, Daejeon 305-343 (Korea)

    2007-11-23

    Effects of heat treatment in nitrogen or Se atmosphere on the properties of Cu(In,Ga)Se{sub 2} (CIGS) nanoparticles were investigated to extract optimum sintering conditions for fabrication of solar cell applicable CIGS absorber films. In nitrogen atmosphere, as the temperature increases from 100 to 400 C the intensity of X-ray diffraction (XRD) peaks corresponding to the (1 1 2), (2 2 0) and (3 1 2) planes of the chalcopyrite CIGS increases, and the peak positions shift to lower angle regions without any particle growth in scanning electron microscopy (SEM) analysis, which is in consistent with the significant In and Ga loss in the EDS data. When the temperature further goes up to 500 C, parts of CIGS are decomposed and Cu and CuSe{sub 2} phases are observed. From these results, the heat treatment in nitrogen atmosphere is found to have no beneficial effect on the sintering of the particles and only induces loss of In and Ga. On the other hand, heat treatment in Se atmosphere at a substrate temperature of 550 C with Se vapor evaporated at 250 and 450 C provided much enhanced growth of the particles, specially up to 500 nm at 450 C, and increased crystallinity without In or Ga loss, reflecting that Se supply played a critical role in the growth of the CIGS nanoparticles. (author)

  7. Optical detectors on GaSe and InSe layered crystals

    Science.gov (United States)

    Kyazym-Zade, A. G.; Agaeva, A. A.; Salmanov, V. M.; Mokhtari, A. G.

    2007-12-01

    Fast uncooled GaSe and InSe detectors that can record ultrashort (10-12 10-9 s) laser pulses in the visual and near-IR ranges are developed. The quick response of the detectors is due to rapid recombination channels with a high capture cross section present in the crystals.

  8. Interface properties and deep levels in InGaAsN/GaAs and GaAsN/GaAs heterojunctions

    Science.gov (United States)

    Polyakov, A. Y.; Smirnov, N. B.; Govorkov, A. V.; Botchkarev, Andrei E.; Nelson, Nicole N.; Fahmi, M. M. E.; Griffin, James A.; Khan, Arif; Noor Mohammad, S.; Johnstone, D. K.; Bublik, V. T.; Chsherbatchev, K. D.; Voronova, M. I.

    2002-12-01

    Interface properties of dilute slightly lattice mismatched GaAsN/GaAs (0.35 at.% N) and closely lattice matched InGaAsN (1 at.% In, 0.35 at.% N) heterojunctions (HJs) were studied by means of capacitance-voltage profiling, deep levels transient spectroscopy (DLTS) and current-voltage measurements. It is found that the lattice matched HJs show no electrical breakdown when the space charge region crosses the interface. The carrier concentration profiles in such HJ show, as expected, the accumulation region on the low-bandgap side and the depletion region on the high-bandgap side of the HJ. This is not the case for the GaAsN/GaAs (GaAsN layer on top) and the GaAs/GaAsN (GaAs layer on top) HJ. The density of deep traps in GaAsN, InGaAsN films and in GaAs films grown on GaAsN underlayers was very much higher than in epitaxial GaAs films. The dominant deep centers were the EL6 and the EL3 electron traps. The interface regions of the GaAs/GaAsN and the InGaAsN/GaAs HJs were shown to be enriched by EL3 traps, while for the GaAsN/GaAs HJ those regions were enriched by EL6 traps which was associated with the former films being Ga-rich and thus facilitating incorporation of oxygen on As sites.

  9. Performance improvement of GaN-based LEDs with step stage InGaN/GaN strain relief layers in GaN-based blue LEDs.

    Science.gov (United States)

    Jia, Chuanyu; Yu, Tongjun; Lu, Huimin; Zhong, Cantao; Sun, Yongjian; Tong, Yuzhen; Zhang, Guoyi

    2013-04-08

    The performance of nitride-based LEDs was improved by inserting dual stage and step stage InGaN/GaN strain relief layer (SRL) between the active layer and n-GaN template. The influences of step stage InGaN/GaN SRL on the structure, electrical and optical characteristics of GaN-based LEDs were investigated. The analysis of strain effect on recombination rate based k·p method indicated 12.5% reduction of strain in InGaN/GaN MQWs by inserting SRL with step stage InGaN/GaN structures. The surface morphology was improved and a smaller blue shift in the electroluminescence (EL) spectral with increasing injection current was observed for LEDs with step stage SRL compared with conventional LEDs. The output power of LEDs operating at 20 mA was about 15.3 mW, increased by more than 108% by using step stage InGaN/GaN SRL, which shows great potential of such InGaN/GaN SRL in modulating InGaN/GaN MQWs optical properties based on its strain relief function.

  10. Influence of GaAsP Insertion Layers on Performance of InGaAsP/InGaP/AlGaAs Quantum-Well Laser

    Institute of Scientific and Technical Information of China (English)

    CAO Yu-Lian; CHEN Liang-Hui; LIAN Peng; MA Wen-Quan; WANG Qing; WU Xu-Ming; HE Guo-Rong; LI Hui; WANG Xiao-Dong; SONG Guo-Feng

    2006-01-01

    @@ We report on the use of very thin GaAsP insertion layers to improve the performance of an InGaAsP/InGaP/AlGaAs single quantum-well laser structure grown by metal organic chemical vapour deposition.

  11. GaInNAs laser gain

    Energy Technology Data Exchange (ETDEWEB)

    CHOW,WENG W.; JONES,ERIC D.; MODINE,NORMAND A.; KURTZ,STEVEN R.; ALLERMAN,ANDREW A.

    2000-05-23

    The optical gain spectra for GaInNAs/GaAs quantum wells are computed using a microscopic laser theory. From these spectra, the peak gain and carrier radiative decay rate as functions of carrier density are determined. These dependences allow the study of the lasing threshold current density of GaInNAs/GaAs quantum well structures.

  12. A new simple multidomain fast multipole boundary element method

    Science.gov (United States)

    Huang, S.; Liu, Y. J.

    2016-09-01

    A simple multidomain fast multipole boundary element method (BEM) for solving potential problems is presented in this paper, which can be applied to solve a true multidomain problem or a large-scale single domain problem using the domain decomposition technique. In this multidomain BEM, the coefficient matrix is formed simply by assembling the coefficient matrices of each subdomain and the interface conditions between subdomains without eliminating any unknown variables on the interfaces. Compared with other conventional multidomain BEM approaches, this new approach is more efficient with the fast multipole method, regardless how the subdomains are connected. Instead of solving the linear system of equations directly, the entire coefficient matrix is partitioned and decomposed using Schur complement in this new approach. Numerical results show that the new multidomain fast multipole BEM uses fewer iterations in most cases with the iterative equation solver and less CPU time than the traditional fast multipole BEM in solving large-scale BEM models. A large-scale fuel cell model with more than 6 million elements was solved successfully on a cluster within 3 h using the new multidomain fast multipole BEM.

  13. Hydrogenation of GaSb/GaAs quantum rings

    Energy Technology Data Exchange (ETDEWEB)

    Hodgson, P. D., E-mail: pdhodgson@hotmail.co.uk; Hayne, M.; Zhuang, Q. D. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom); Ahmad Kamarudin, M. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom); Department of Physics, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Darul Ehsan (Malaysia); Birindelli, S.; Capizzi, M. [Dipartimento di Fisica, Sapienza Universita di Roma, Piazzale A. Moro 2, 00185 Roma (Italy)

    2014-08-25

    We present the results of photoluminescence measurements on hydrogenated type-II GaSb/GaAs quantum dot/ring (QD/QR) samples at temperatures ranging from 4.2 K to 400 K. Hydrogenation is found to suppress optically induced charge depletion (associated with the presence of carbon acceptors in this system). A redshift of the QD\\QR emission energy of a few tens of meV is observed at temperatures ≥300 K, consistent with a reduction in average occupancy by ∼1 hole. These effects are accompanied by a reduction in PL intensity post-hydrogenation. We conclude that although hydrogenation may have neutralized the carbon acceptors, multiple hole occupancy of type-II GaSb/GaAs QD/QRs is very likely a precondition for intense emission, which would make extending the wavelength significantly beyond 1300 nm at room temperature difficult.

  14. Low threshold all-optical crossbar switch on GaAs-GaAlAs channel waveguide arrays

    Science.gov (United States)

    Jannson, Tomasz; Kostrzewski, Andrew

    1994-09-01

    During the Phase 2 project entitled 'Low Threshold All-Optical Crossbar Switch on GaAs - GaAlAs Channel Waveguide Array,' Physical Optics Corporation (POC) developed the basic principles for the fabrication of all-optical crossbar switches. Based on this development. POC fabricated a 2 x 2 GaAs/GaAlAs switch that changes the direction of incident light with minimum insertion loss and nonlinear distortion. This unique technology can be used in both analog and digital networks. The applications of this technology are widespread. Because the all-optical network does not have any speed limitations (RC time constant), POC's approach will be beneficial to SONET networks, phased array radar networks, very high speed oscilloscopes, all-optical networks, IR countermeasure systems, BER equipment, and the fast growing video conferencing network market. The novel all-optical crossbar switch developed in this program will solve interconnect problems. and will be a key component in the widely proposed all-optical 200 Gb/s SONET/ATM networks.

  15. Ordered arrays of InGaN/GaN dot-in-a-wire nanostructures as single photon emitters

    Science.gov (United States)

    Lazić, Snežana; Chernysheva, Ekaterina; Gačević, Žarko; García-Lepetit, Noemi; van der Meulen, Herko P.; Müller, Marcus; Bertram, Frank; Veit, Peter; Christen, Jürgen; Torres-Pardo, Almudena; González Calbet, José M.; Calleja, Enrique; Calleja, José M.

    2015-03-01

    The realization of reliable single photon emitters operating at high temperature and located at predetermined positions still presents a major challenge for the development of solid-state systems for quantum light applications. We demonstrate single-photon emission from two-dimensional ordered arrays of GaN nanowires containing InGaN nanodisks. The structures were fabricated by molecular beam epitaxy on (0001) GaN-on-sapphire templates patterned with nanohole masks prepared by colloidal lithography. Low-temperature cathodoluminescence measurements reveal the spatial distribution of light emitted from a single nanowire heterostructure. The emission originating from the topmost part of the InGaN regions covers the blue-to-green spectral range and shows intense and narrow quantum dot-like photoluminescence lines. These lines exhibit an average linear polarization ratio of 92%. Photon correlation measurements show photon antibunching with a g(2)(0) values well below the 0.5 threshold for single photon emission. The antibunching rate increases linearly with the optical excitation power, extrapolating to the exciton decay rate of ~1 ns-1 at vanishing pump power. This value is comparable with the exciton lifetime measured by time-resolved photoluminescence. Fast and efficient single photon emitters with controlled spatial position and strong linear polarization are an important step towards high-speed on-chip quantum information management.

  16. Cholesky decomposed density matrices in Laplace transform Moeller-Plesset perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    Clin, Lucien Cyril

    2012-06-04

    The evaluation of correlation energies in the canonical formulation of second order Moeller-Plesset Perturbation Theory (MP2) is limited to systems of about 100 atoms, due to the method's steep O(N{sup 5}) scaling. In order to extend the method's applicability to larger systems, it is therefore imperative to develop alternative formulations that allow for efficient scaling reduction. One such approach is the Laplace transform formalism introduced by Almloef and Haeser, with which MP2 can be expressed in the basis of atom-centered orbitals (AO-MP2), whose local character allows to take advantage of the short range of correlation effects. The overall scaling can thus be reduced through the application of integral pre-selection schemes to discard all numerically irrelevant contributions to the energy. This dissertation is concerned with the study of Cholesky decomposed pseudo-density (CDD) matrices within this AO-MP2 scheme. For technical reasons, namely, the AO-MP2 implementation of Doser et al. is restricted to the evaluation of the opposite spin component of MP2, and is thus bound to the empirical scaled opposite spin parametrization procedure. Applying a Cholesky decomposition to the occurring pseudo-density matrices, the same spin component required for full MP2 energies is naturally included in the resulting CDD-MP2 method, whereby the ab initio character is restored. The investigation of the CDD-approach was further motivated by the fact that the orbitals generated by the decomposition are localized (for electronically non-delocalized systems), and thus allow for the pre-selection of only numerically significant integrals. However, although it could be shown on simple systems that the method does in principle scale linearly, its application to even moderately sized systems with large basis sets is yet hampered by severe technical and numerical difficulties, which are analysed and discussed in detail. Another closely related project has been to extend

  17. First 3D radiative transfer with scattering for domain-decomposed MHD simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hayek, W [Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston Creek ACT 2611 (Australia)], E-mail: hayek@mpa-garching.mpg.de

    2008-12-15

    This paper presents an implementation of the Gauss-Seidel solver for radiative transfer with scattering in the Oslo Stagger Code. It fully supports MPI parallelism through domain decomposition of the simulation box, enabling fast computation of radiative transfer at a high resolution. Continuum and line opacities are treated with either a multigroup method or opacity sampling. Line scattering probabilities are estimated using the van Regemorter approximation for de-excitation rates of electron collisions. A solar-type test simulation with continuum and line scattering exhibits a steeper temperature gradient due to decreased radiative heating above the optical surface when compared with the strict local thermodynamic equilibrium (LTE) case. The classical van Regemorter approximation may overestimate the importance of line scattering, implying that the true temperature structure will be in between the LTE case and the scattering case considered here. It is demonstrated that continuum scattering is unimportant in the case of the Sun.

  18. First 3D radiative transfer with scattering for domain-decomposed MHD simulations

    Science.gov (United States)

    Hayek, W.

    2008-12-01

    This paper presents an implementation of the Gauss Seidel solver for radiative transfer with scattering in the Oslo Stagger Code. It fully supports MPI parallelism through domain decomposition of the simulation box, enabling fast computation of radiative transfer at a high resolution. Continuum and line opacities are treated with either a multigroup method or opacity sampling. Line scattering probabilities are estimated using the van Regemorter approximation for de-excitation rates of electron collisions. A solar-type test simulation with continuum and line scattering exhibits a steeper temperature gradient due to decreased radiative heating above the optical surface when compared with the strict local thermodynamic equilibrium (LTE) case. The classical van Regemorter approximation may overestimate the importance of line scattering, implying that the true temperature structure will be in between the LTE case and the scattering case considered here. It is demonstrated that continuum scattering is unimportant in the case of the Sun.

  19. Impacts of SiN passivation on the degradation modes of AlGaN/GaN high electron mobility transistors under reverse-bias stress

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Wei; Ma, Xiao-Hua, E-mail: xhma@xidian.edu.cn, E-mail: yhao@xidian.edu.cn; Hou, Bin; Zhu, Jie-Jie [School of Advanced Materials and Nanotechnology, Xidian University, Xi' an 710071 (China); Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China); Chen, Yong-He; Zheng, Xue-Feng; Zhang, Jin-Cheng; Hao, Yue, E-mail: xhma@xidian.edu.cn, E-mail: yhao@xidian.edu.cn [Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China)

    2014-10-27

    Impacts of SiN passivation on the degradation modes of AlGaN/GaN high electron mobility transistors are investigated. The gate leakage current decreases significantly upon removing the SiN layer and no clear critical voltage for the sudden degradation of the gate leakage current can be observed in the reverse-bias step-stress experiments. Gate-lag measurements reveal the decrease of the fast-state surface traps and the increase of slow-state traps after the passivation layer removal. It is postulated that consistent surface charging relieves the electric field peak on the gate edge, thus the inverse piezoelectric effect is shielded.

  20. Fast growth in control

    NARCIS (Netherlands)

    Z. Rico (Zulay)

    2009-01-01

    textabstractThe focus of this paper is on the influence of the fast growth of organizations on the design process of management control systems. What are the management accounting and control problems that a fast growth organization encounters that can be ascribed to this growth. What are the circum

  1. Fast protein folding kinetics

    Science.gov (United States)

    Gelman, Hannah; Gruebele, Martin

    2014-01-01

    Fast folding proteins have been a major focus of computational and experimental study because they are accessible to both techniques: they are small and fast enough to be reasonably simulated with current computational power, but have dynamics slow enough to be observed with specially developed experimental techniques. This coupled study of fast folding proteins has provided insight into the mechanisms which allow some proteins to find their native conformation well less than 1 ms and has uncovered examples of theoretically predicted phenomena such as downhill folding. The study of fast folders also informs our understanding of even “slow” folding processes: fast folders are small, relatively simple protein domains and the principles that govern their folding also govern the folding of more complex systems. This review summarizes the major theoretical and experimental techniques used to study fast folding proteins and provides an overview of the major findings of fast folding research. Finally, we examine the themes that have emerged from studying fast folders and briefly summarize their application to protein folding in general as well as some work that is left to do. PMID:24641816

  2. Ramadan, faste og graviditet

    DEFF Research Database (Denmark)

    Ahmed, Urfan Zahoor; Lykke, Jacob Alexander

    2014-01-01

    , but there are reports of decreased foetal movements. Furthermore, the fasting may have long-term health consequences for the offspring, especially when they reach their middle age. According to Islam and the interpretation, pregnant and breast-feeding women are allowed to postpone the fasting of the month of Ramadan...

  3. Fast protein folding kinetics.

    Science.gov (United States)

    Gelman, Hannah; Gruebele, Martin

    2014-05-01

    Fast-folding proteins have been a major focus of computational and experimental study because they are accessible to both techniques: they are small and fast enough to be reasonably simulated with current computational power, but have dynamics slow enough to be observed with specially developed experimental techniques. This coupled study of fast-folding proteins has provided insight into the mechanisms, which allow some proteins to find their native conformation well fast folders also informs our understanding of even 'slow' folding processes: fast folders are small; relatively simple protein domains and the principles that govern their folding also govern the folding of more complex systems. This review summarizes the major theoretical and experimental techniques used to study fast-folding proteins and provides an overview of the major findings of fast-folding research. Finally, we examine the themes that have emerged from studying fast folders and briefly summarize their application to protein folding in general, as well as some work that is left to do.

  4. Optical and scintillation characteristics of Gd2YAl2Ga3O12:Ce and Lu2YAl2Ga3O12:Ce single crystals

    Science.gov (United States)

    Chewpraditkul, Warut; Sakthong, Ongsa; Pattanaboonmee, Nakarin; Chewpraditkul, Weerapong; Szczesniak, Tomasz; Swiderski, Lukasz; Moszynski, Marek; Kamada, Kei; Yoshikawa, Akira; Nikl, Martin

    2017-06-01

    The optical and scintillation characteristics of Gd2YAl2Ga3O12:Ce and Lu2YAl2Ga3O12:Ce single crystals are investigated. At 662 keV γ-rays, light yield (LY) of 37,900 ph/MeV and energy resolution of 7.0% obtained for Gd2YAl2Ga3O12:Ce are superior to those of 18,900 ph/MeV and 11.5% obtained for Lu2YAl2Ga3O12:Ce. Scintillation decays are measured using the time-correlated single photon counting technique. A fast component decay time of 45 ns with relative intensity of 88% obtained for Lu2YAl2Ga3O12:Ce is superior to that of 50 ns (65%) for Gd2YAl2Ga3O12:Ce. The linear attenuation coefficient at 662 keV γ-rays is also determined and discussed.

  5. An unambiguous identification of 2D electron gas features in the photoluminescence spectrum of AlGaN/GaN heterostructures

    Science.gov (United States)

    Jana, Dipankar; Sharma, T. K.

    2016-07-01

    A fast and non-destructive method for probing the true signatures of 2D electron gas (2DEG) states in AlGaN/GaN heterostructures is presented. Two broad features superimposed with interference oscillations are observed in the low temperature photoluminescence (PL) spectrum. The two features are identified as the ground and excited 2DEG states which are confirmed by comparing the PL spectra of as-grown and top barrier layer etched samples. Broad PL features disappear at a certain temperature along with the associated interference oscillations. Furthermore, the two broad PL features depicts specific temperature and excitation intensity dependencies which make them easily distinguishable from the bandedge excitonic or defect related PL features. The presence of strong interference oscillations associated with the 2DEG PL features is explained by considering the localized generation of PL signal at the AlGaN/GaN heterointerface. Finally, a large value of the polarization induced electric field of ~1.01 MV cm-1 is reported from PL measurements for AlGaN/GaN HEMT structures. It became possible only when the true identification of 2DEG features was made possible by the proposed method.

  6. Chemical beam epitaxy of GaAs1-xNx using MMHy and DMHy precursors, modeled by ab initio study of GaAs(100) surfaces stability over As2, H2 and N2

    Science.gov (United States)

    Valencia, Hubert; Kangawa, Yoshihiro; Kakimoto, Koichi

    2017-06-01

    Using ab initio calculations, a simple model for GaAs1-xNx vapor-phase epitaxy on (100) surface of GaAs was created. By studying As2 and H2 molecules adsorptions and As/N atom substitutions on (100) GaAs surfaces, we obtain a relative stability diagram of all stable surfaces under varying As2, H2, and N2 conditions. We previously proved that this model could describe the vapor-phase epitaxy of GaAs1-x Nx with simple, fully decomposed, precursors. In this paper, we show that in more complex reaction conditions using monomethylhydrazine (MMHy), and dimethylhydrazine (DMHy), it is still possible to use our model to obtain an accurate description of the temperature and pressure stability domains for each surfaces, linked to chemical beam epitaxy (CBE) growth conditions. Moreover, the different N-incorporation regimes observed experimentally at different temperature can be explain and predict by our model. The use of MMHy and DMHy precursors can also be rationalized. Our model should then help to better understand the conditions needed to obtain an high quality GaAs1-xNx using vapor-phase epitaxy.

  7. Fast ejendom III

    DEFF Research Database (Denmark)

    Munk-Hansen, Carsten

    Bogen er det tredje bind af tre planlagte bind om fast ejendom: I Overdragelsen, II Bolighandlen og III Ejerbeføjelsen. Fremstillingens giver et grundigt overblik over centrale områder af en omfattende regulering af fast ejendom, med angivelse af litteratur, hvor læseren kan søge yderligere...... oplysning. En ejer af fast ejendom er på særdeles mange områder begrænset i sin råden sammenlignet med ejeren af et formuegode i almindelighed. Fremstillingen tager udgangspunkt i ejerens perspektiv (fremfor samfundets eller myndighedernes). Både den privatretlige og offentligretlige regulering behandles......, eksempelvis ejendomsdannelsen, servitutter, naboretten, hævd, zoneinddelingen, den fysiske planlægning, beskyttelse af natur, beskyttelse af kultur, forurening fra fast ejendom, erstatning for forurening, jordforurening, ekspropriation, byggeri og adgang til fast ejendom....

  8. Islamic Fasting and Diabetes

    Directory of Open Access Journals (Sweden)

    Fereidoun Azizi

    2013-07-01

    Full Text Available The aim of this article is to review health-related aspects of Ramadan fasting in normal individuals and diabetics. During fasting days of Ramadan, glucose homeostasis is maintained by meal taken bepore dawn and by liver glycogen stores. Changes in serum lipids are variable and defend on the quality and quantity of food consumption and changes in weight. Compliant, well controlled type 2 diabetics may observe Ramadan fasting; but fasting is not recommended for type 1, non complaint, poorly controlled and pregnant diabetics. Although Ramadan fasting is safe for all healthy individuals and well controlled diabetics, those with uncontrolled diabetics and diabetics with complications should consult physicians and follow scientific recommendations.

  9. Fast Spectrum Reactors

    CERN Document Server

    Todd, Donald; Tsvetkov, Pavel

    2012-01-01

    Fast Spectrum Reactors presents a detailed overview of world-wide technology contributing to the development of fast spectrum reactors. With a unique focus on the capabilities of fast spectrum reactors to address nuclear waste transmutation issues, in addition to the well-known capabilities of breeding new fuel, this volume describes how fast spectrum reactors contribute to the wide application of nuclear power systems to serve the global nuclear renaissance while minimizing nuclear proliferation concerns. Readers will find an introduction to the sustainable development of nuclear energy and the role of fast reactors, in addition to an economic analysis of nuclear reactors. A section devoted to neutronics offers the current trends in nuclear design, such as performance parameters and the optimization of advanced power systems. The latest findings on fuel management, partitioning and transmutation include the physics, efficiency and strategies of transmutation, homogeneous and heterogeneous recycling, in addit...

  10. Adsorbate interactions on the GaN(0001) surface and their effect on diffusion barriers and growth morphology.

    Science.gov (United States)

    Chugh, Manjusha; Ranganathan, Madhav

    2017-01-18

    Studying the adsorbate interactions on a surface helps in understanding the growing surface morphologies and calculating the effective surface diffusion barriers. We study the interaction between Ga-Ga, N-N and Ga-N adatom pairs on the polar GaN(0001) surface using ab initio calculations based on density functional theory. The interaction energy between two adatoms on the surface does not seem to follow definite trends with increasing distance between the adatoms. The presence of a number of possible reconstructions on clean GaN(0001) and periodic effects due to the finite size complicate the analysis of the interactions. Various components of the total interaction energy are separated. We find that there is a large substrate lattice distortion caused due to Ga and N adatoms. The resulting elastic interaction is a major component of the interactions between the adatoms on the GaN(0001) surface. The dipolar interaction is much smaller in magnitude. We also evaluate the component of the interaction energy due to the substrate-mediated electronic interactions. The barriers for surface hopping of adatoms are significantly modified in the presence of other adatoms. We identify several possible surface hopping processes for Ga and N adatoms and calculate their barriers. In particular, we find that the N adatom has a lower barrier to move to an adjoining site on the other side of a neighboring Ga adatom. Kinetic Monte Carlo simulations are performed to see the effect of adatom interactions on the growing surface morphologies of GaN(0001). At the submonolayer growth stage, the fast diffusion of N adatoms located near Ga adatoms leads to more regular island features. In this way, we illustrate the role of adatom interactions in the initial surface nucleation and the morphologies of the growing GaN(0001) film.

  11. Quantitative and qualitative intrapatient comparison of 68Ga-DOTATOC and 68Ga-DOTATATE: net uptake rate for accurate quantification.

    Science.gov (United States)

    Velikyan, Irina; Sundin, Anders; Sörensen, Jens; Lubberink, Mark; Sandström, Mattias; Garske-Román, Ulrike; Lundqvist, Hans; Granberg, Dan; Eriksson, Barbro

    2014-02-01

    Quantitative imaging and dosimetry are crucial for individualized treatment during peptide receptor radionuclide therapy (PRRT). (177)Lu-DOTATATE and (68)Ga-DOTATOC/(68)Ga-DOTATATE are used, respectively, for PRRT and PET examinations targeting somatostatin receptors (SSTRs) in patients affected by neuroendocrine tumors. The aim of the study was to quantitatively and qualitatively compare the performance of (68)Ga-DOTATOC and (68)Ga-DOTATATE in the context of subsequent PRRT with (177)Lu-DOTATATE under standardized conditions in the same patient as well as to investigate the sufficiency of standardized uptake value (SUV) for estimation of SSTR expression. Ten patients with metastatic neuroendocrine tumors underwent one 45-min dynamic and 3 whole-body PET/CT examinations at 1, 2, and 3 h after injection with both tracers. The number of detected lesions, SUVs in lesions and normal tissue, total functional tumor volume, and SSTR volume (functional tumor volume multiplied by mean SUV) were investigated for each time point. Net uptake rate (Ki) was calculated according to the Patlak method for 3 tumors per patient. There were no significant differences in lesion count, lesion SUV, Ki, functional tumor volume, or SSTR volume between (68)Ga-DOTATOC and (68)Ga-DOTATATE at any time point. The detection rate was similar, although with differences for single lesions in occasional patients. For healthy organs, marginally higher uptake of (68)Ga-DOTATATE was observed in kidneys, bone marrow, and liver at 1 h. (68)Ga-DOTATOC uptake was higher in mediastinal blood pool at the 1-h time point (P = 0.018). The tumor-to-liver ratio was marginally higher for (68)Ga-DOTATOC at the 3-h time point (P = 0.037). Blood clearance was fast and similar for both tracers. SUV did not correlate with Ki linearly and achieved saturation for a Ki of greater than 0.2 mL/cm(3)/min, corresponding to an SUV of more than 25. (68)Ga-DOTATOC and (68)Ga-DOTATATE are suited equally well for staging and

  12. Detection of miniband formation in strain-balanced InGaAs/GaAsP quantum well solar cells by using a piezoelectric photothermal spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Aihara, Taketo; Fukuyama, Atsuhiko; Yokoyama, Yuki; Kojima, Michiya; Ikari, Tetsuo [Faculty of Engineering, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192 (Japan); Suzuki, Hidetoshi [Interdisciplinary Research Organization, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192 (Japan); Sugiyama, Masakazu [School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032 (Japan); Nakano, Yoshiaki [Research Center for Advanced Science and Technology, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032 (Japan)

    2014-07-28

    To investigate the effect of the miniband formation on the optical absorption spectrum, we adopted two non-destructive methodologies of piezoelectric photothermal (PPT) and photoreflectance (PR) spectroscopies for strain-balanced InGaAs/GaAsP multiple quantum-well (MQW) and superlattice (SL) structures inserted GaAs p-i-n solar cells. Because the barrier widths of the SL sample were very thin, miniband formations caused by coupling the wave functions between adjacent wells were expected. From PR measurements, a critical energy corresponding to the inter-subband transition between first-order electron and hole subbands was estimated for MQW sample, whereas two critical energies corresponding to the mini-Brillouin-zone center (Γ) and edge (π) were obtained for SL sample. The miniband width was calculated to be 19 meV on the basis of the energy difference between Γ and π. This coincided with the value of 16 meV calculated using the simple Kronig–Penney potential models. The obtained PPT spectrum for the SL sample was decomposed into the excitonic absorption and inter-miniband transition components. The latter component was expressed using the arcsine-like signal rise corresponding to the Γ point in the mini-Brillouin zone that was enhanced by the Sommerfeld factor. The usefulness of the PPT methodology for investigating the inserted MQW and/or SL structure inserted solar cells is clearly demonstrated.

  13. Diffusion-driven and excitation-dependent recombination rate in blue InGaN/GaN quantum well structures

    Energy Technology Data Exchange (ETDEWEB)

    Aleksiejūnas, R.; Gelžinytė, K.; Nargelas, S., E-mail: saulius.nargelas@ff.vu.lt; Jarašiūnas, K. [Department of Semiconductor Optoelectronics, Institute of Applied Research, Vilnius University, Saulėtekio 9–III, 10222 Vilnius (Lithuania); Vengris, M. [Laser Research Center, Vilnius University, Saulėtekio 10, 10223 Vilnius (Lithuania); Armour, E. A.; Byrnes, D. P.; Arif, R. A.; Lee, S. M.; Papasouliotis, G. D. [Veeco Instruments, Turbodisc Operations, 394 Elizabeth Avenue, Somerset, New Jersey 08873 (United States)

    2014-01-13

    We report on diffusion-driven and excitation-dependent carrier recombination rate in multiple InGaN/GaN quantum wells by using photoluminescence, light-induced absorption, and diffraction techniques. We demonstrate gradually increasing with excitation carrier diffusivity and its correlation with the recombination rate. At low carrier densities, an increase in radiative emission and carrier lifetime was observed due to partial saturation of non-radiative recombination centers. However, at carrier densities above ∼5 × 10{sup 18} cm{sup −3}, a typical value of photoluminescence efficiency droop, a further increase of diffusivity forces the delocalized carriers to face higher number of fast non-radiative recombination centers leading to an increase of non-radiative losses.

  14. Gibberellin biosynthesis in maize. Metabolic studies with GA{sub 15}, GA{sub 24}, GA{sub 25}, GA{sub 7}, and 2,3-dehydro-GA{sub 9}

    Energy Technology Data Exchange (ETDEWEB)

    Davis, G.; Kobayashi, Masatomo; Phinney, B.O.; Lange, T.; Croker, S.J.; Gaskin, P.; MacMillan, J.

    1999-11-01

    [17-{sup 14}C]-Labeled GA{sub 15}, GA{sub 24}, GA{sub 25}, GA{sub 7}, and 2,3-dehydro-GA{sub 9} were separately injected into normal, dwarf-1 (d1), and dwarf-5 (d5) seedlings of maize (Zea mays L.). Purified radioactive metabolites from the plant tissues were identified by sull-scan gas chromatography-mass spectrometry and Kovats retention index data. The metabolites from GA{sub 15} were GA{sub 44}, GA{sub 19}, GA{sub 20}, GA{sub 113}, and GA{sub 15}-15,16-ene (artifact?). GA{sub 24} was metabolized to GA{sub 19}, GA{sub 20}, and GA{sub 17}. The metabolites from GA{sub 25} were GA{sub 17}, GA{sub 25} 16{alpha},17-H{sub 2}-17-OH, and HO-GA{sub 25} (hydroxyl position not determined). GA{sub 7} was metabolized to GA{sub 30}, GA{sub 3}, isoGA{sub 3} (artifact?), and trace amounts of GA{sub 7}-diene-diacid (artifact?). 2,3-Dehydro-GA{sub 9} was metabolized to GA{sub 5}, GA{sub 7} (trace amounts), 2,3-dehydro-GA{sub 10} (artifact?), GA{sub 31}, and GA{sub 62}. Their results provide additional in vivo evidence of a metabolic grid in maize (i.e., pathway convergence). The grid connects members of a putative, non-early 3,130hydroxylation branch pathway to the corresponding members of the previously documented early 13-hydroxylation branch pathway. The inability to detect the sequence GA{sub 12}{r{underscore}arrow} GA{sub 15} {r{underscore}arrow} GA{sub 24} {r{underscore}arrow} GA{sub 9} indicates that the non-early 3,13-hydroxylation pathway probably plays a minor role in the origin of bioactive gibberellins in maize.

  15. Evolution of morphology and microstructure of GaAs/GaSb nanowire heterostructures.

    Science.gov (United States)

    Shi, Suixing; Zhang, Zhi; Lu, Zhenyu; Shu, Haibo; Chen, Pingping; Li, Ning; Zou, Jin; Lu, Wei

    2015-01-01

    In this paper, we successfully grow GaAs/GaSb core-shell heterostructure nanowires (NWs) by molecular beam epitaxy (MBE). The as-grown GaSb shell layer forms a wurtzite structure instead of the zinc blende structure that has been commonly reported. Meanwhile, a bulgy GaSb nanoplate also appears on top of GaAs/GaSb core-shell NWs and possesses a pure zinc blende phase. The growth mode for core-shell morphology and underlying mechanism for crystal phase selection of GaAs/GaSb nanowire heterostructures are discussed in detail.

  16. STR analysis of human DNA from maggots fed on decomposing bodies: Assessment of the time period for successful analysis

    Directory of Open Access Journals (Sweden)

    Daniel Gachuiri Njau

    2016-09-01

    Full Text Available Frequently, forensic entomology is applied in the use of insect maggots for the identification of specimens or remains of humans. Maggot crop analysis could be valuable in criminal investigations when maggots are found at a crime scene and a corpse is absent. Human short tandem repeat (STR has previously been used to support the association of maggots to a specific corpse but not in the period at which the body has been decomposing. The aim of this research was to assess the time period for successful STR analyses of human DNA from third instar maggots (Protophormia terraenovae obtained from decomposing human corpses as well as to investigate the human DNA turnover and degradation in the maggot crop after they are removed from food and/or are fed on a beef (a new/different food source. Results showed that the amount of human DNA recovered from maggots decreased with time in all cases. For maggots fed on beef, the human DNA could only be recovered up to day two and up to day four for the starved maggots. STR analyses of human DNA from maggots’ crop content using 16 loci generated profiles that matched those of reference samples although some of the alleles were not amplifiable therefore generating partial profiles for the samples starved for 4 days and those fed on beef. This may be due to nuclease activity present in the gut of larvae that may have caused degradation of DNA and consequently reduction in DNA yield. It was possible to identify the decomposing body using STRs as markers.

  17. Enhanced summer warming reduces fungal decomposer diversity and litter mass loss more strongly in dry than in wet tundra.

    Science.gov (United States)

    Christiansen, Casper T; Haugwitz, Merian S; Priemé, Anders; Nielsen, Cecilie S; Elberling, Bo; Michelsen, Anders; Grogan, Paul; Blok, Daan

    2017-01-01

    Many Arctic regions are currently experiencing substantial summer and winter climate changes. Litter decomposition is a fundamental component of ecosystem carbon and nutrient cycles, with fungi being among the primary decomposers. To assess the impacts of seasonal climatic changes on litter fungal communities and their functioning, Betula glandulosa leaf litter was surface-incubated in two adjacent low Arctic sites with contrasting soil moisture regimes: dry shrub heath and wet sedge tundra at Disko Island, Greenland. At both sites, we investigated the impacts of factorial combinations of enhanced summer warming (using open-top chambers; OTCs) and deepened snow (using snow fences) on surface litter mass loss, chemistry and fungal decomposer communities after approximately 1 year. Enhanced summer warming significantly restricted litter mass loss by 32% in the dry and 17% in the wet site. Litter moisture content was significantly reduced by summer warming in the dry, but not in the wet site. Likewise, fungal total abundance and diversity were reduced by OTC warming at the dry site, while comparatively modest warming effects were observed in the wet site. These results suggest that increased evapotranspiration in the OTC plots lowered litter moisture content to the point where fungal decomposition activities became inhibited. In contrast, snow addition enhanced fungal abundance in both sites but did not significantly affect litter mass loss rates. Across sites, control plots only shared 15% of their fungal phylotypes, suggesting strong local controls on fungal decomposer community composition. Nevertheless, fungal community functioning (litter decomposition) was negatively affected by warming in both sites. We conclude that although buried soil organic matter decomposition is widely expected to increase with future summer warming, surface litter decay and nutrient turnover rates in both xeric and relatively moist tundra are likely to be significantly restricted by

  18. GaAs-MnAs nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Sadowski, Janusz [MAX-Lab, Lund University, P.O. Box 118, 221 00 Lund (Sweden); Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warszawa (Poland); Siusys, Aloyzas; Wojciechowski, Tomasz; Reszka, Anna; Kowalski, Bogdan [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warszawa (Poland); Kovacs, Andras; Kasama, Takeshi [Center for Electron Nanoscopy, Technical University of Denmark, Kgs. Lyngby 2800 (Denmark); Dunin-Borkowski, Rafal E. [Center for Electron Nanoscopy, Technical University of Denmark, Kgs. Lyngby 2800 (Denmark); Institute for Microstructure Research, Peter Gruenberg Institute, Forschungszentrum Juelich, 52425 Juelich (Germany)

    2011-07-15

    Different strategies for obtaining nanowires (NWs) with ferromagnetic properties using the molecular beam epitaxy (MBE) grown nanostructures combining GaAs and Mn were investigated. Four types of structures have been studied: (i) self-catalyzed GaAs:Mn NWs grown at low temperatures on GaAs(100) substrates; (ii) GaAs:Mn NWs grown at high temperatures on Si(100) substrates; (iii) GaAs-GaMnAs core-shell NW structures; (iv) GaAs-MnAs core-shell NW structures grown on Si(100). Structures of types (i), (iii), and (iv) exhibit ferromagnetic properties. Right: Scanning electron microscopy image of Mn doped GaAs NWs with Ga droplets at the tops, grown by MBE on oxidized Si(100) substrate in the autocatalytic growth mode. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. FAST Construction Progress

    Science.gov (United States)

    Nan, R. D.; Zhang, H. Y.; Zhang, Y.; Yang, L.; Cai, W. J.; Liu, N.; Xie, J. T.; Zhang, S. X.

    2016-11-01

    The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is a Chinese mega-science project to build the largest single dish radio telescope in the world. A unique karst depression in Guizhou province has been selected as the site to build an active reflector radio telescope with a diameter of 500 m and three outstanding aspects, which enables FAST to have a large sky coverage and the ability of observing astronomical targets with a high precision. Chinese Academy of Sciences and Guizhou province are in charge of FAST construction. The first light of the telescope was expected on September 25, 2016.

  20. Fast Breeder Reactor studies

    Energy Technology Data Exchange (ETDEWEB)

    Till, C.E.; Chang, Y.I.; Kittel, J.H.; Fauske, H.K.; Lineberry, M.J.; Stevenson, M.G.; Amundson, P.I.; Dance, K.D.

    1980-07-01

    This report is a compilation of Fast Breeder Reactor (FBR) resource documents prepared to provide the technical basis for the US contribution to the International Nuclear Fuel Cycle Evaluation. The eight separate parts deal with the alternative fast breeder reactor fuel cycles in terms of energy demand, resource base, technical potential and current status, safety, proliferation resistance, deployment, and nuclear safeguards. An Annex compares the cost of decommissioning light-water and fast breeder reactors. Separate abstracts are included for each of the parts.

  1. Gas cooled fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1972-06-01

    Although most of the development work on fast breeder reactors has been devoted to the use of liquid metal cooling, interest has been expressed for a number of years in alternative breeder concepts using other coolants. One of a number of concepts in which interest has been retained is the Gas-Cooled Fast Reactor (GCFR). As presently envisioned, it would operate on the uranium-plutonium mixed oxide fuel cycle, similar to that used in the Liquid Metal Fast Breeder Reactor (LMFBR), and would use helium gas as the coolant.

  2. Environmental safety to decomposer invertebrates of azadirachtin (neem) as a systemic insecticide in trees to control emerald ash borer.

    Science.gov (United States)

    Kreutzweiser, David; Thompson, Dean; Grimalt, Susana; Chartrand, Derek; Good, Kevin; Scarr, Taylor

    2011-09-01

    The non-target effects of an azadirachtin-based systemic insecticide used for control of wood-boring insect pests in trees were assessed on litter-dwelling earthworms, leaf-shredding aquatic insects, and microbial communities in terrestrial and aquatic microcosms. The insecticide was injected into the trunks of ash trees at a rate of 0.2 gazadirachtin cm(-1) tree diameter in early summer. At the time of senescence, foliar concentrations in most (65%) leaves where at or below detection (emerald ash borer, resultant foliar concentrations in senescent leaf material are likely to pose little risk of harm to decomposer invertebrates.

  3. Decomposing wage distributions on a large data set - a quantile regression analysis of the gender wage gap

    DEFF Research Database (Denmark)

    Albæk, Karsten; Brink Thomsen, Lars

    in this paper. Decompositions show that most of the glass ceiling is related to segregation in the form of either composition effects or different returns to males and females. A counterfactual wage distribution without differences in the constant terms (or ‘discrimination’) implies substantial changes......This paper presents and implements a procedure that makes it possible to decompose wage distributions on large data sets. We replace bootstrap sampling in the standard Machado-Mata procedure with ‘non-replacement subsampling’, which is more suitable for the linked employer-employee data applied...... in gender wage differences in the lower part of the wage distribution....

  4. Highly concentrated synthesis of copper-zinc-tin-sulfide nanocrystals with easily decomposable capping molecules for printed photovoltaic applications

    Science.gov (United States)

    Kim, Youngwoo; Woo, Kyoohee; Kim, Inhyuk; Cho, Yong Soo; Jeong, Sunho; Moon, Jooho

    2013-10-01

    Among various candidate materials, Cu2ZnSnS4 (CZTS) is a promising earth-abundant semiconductor for low-cost thin film solar cells. We report a facile, less toxic, highly concentrated synthetic method utilizing the heretofore unrecognized, easily decomposable capping ligand of triphenylphosphate, where phase-pure, single-crystalline, and well-dispersed colloidal CZTS nanocrystals were obtained. The favorable influence of the easily decomposable capping ligand on the microstructural evolution of device-quality CZTS absorber layers was clarified based on a comparative study with commonly used oleylamine-capped CZTS nanoparticles. The resulting CZTS nanoparticles enabled us to produce a dense and crack-free absorbing layer through annealing under a N2 + H2S (4%) atmosphere, demonstrating a solar cell with an efficiency of 3.6% under AM 1.5 illumination.Among various candidate materials, Cu2ZnSnS4 (CZTS) is a promising earth-abundant semiconductor for low-cost thin film solar cells. We report a facile, less toxic, highly concentrated synthetic method utilizing the heretofore unrecognized, easily decomposable capping ligand of triphenylphosphate, where phase-pure, single-crystalline, and well-dispersed colloidal CZTS nanocrystals were obtained. The favorable influence of the easily decomposable capping ligand on the microstructural evolution of device-quality CZTS absorber layers was clarified based on a comparative study with commonly used oleylamine-capped CZTS nanoparticles. The resulting CZTS nanoparticles enabled us to produce a dense and crack-free absorbing layer through annealing under a N2 + H2S (4%) atmosphere, demonstrating a solar cell with an efficiency of 3.6% under AM 1.5 illumination. Electronic supplementary information (ESI) available: Experimental methods for CZTS nanocrystal synthesis, device fabrication, and characterization; the size distribution and energy dispersive X-ray (EDX) spectra of the synthesized CZTS nanoparticles; UV-vis spectra of the

  5. Enzymatic Strategies and Carbon Use Efficiency of a Litter-Decomposing Fungus Grown on Maize Leaves, Stems, and Roots.

    Science.gov (United States)

    Lashermes, Gwenaëlle; Gainvors-Claisse, Angélique; Recous, Sylvie; Bertrand, Isabelle

    2016-01-01

    Soil microorganisms can control the soil cycles of carbon (C), and depending on their C-use efficiency (CUE), these microorganisms either contribute to C stabilization in soil or produce CO2 when decomposing organic matter. However, little is known regarding the enzyme investment of microbial decomposers and the effects on their CUE. Our objective was to elucidate the strategies of litter-decomposing fungi as a function of litter quality. Fungal biosynthesis and respiration were accounted for by quantifying the investment in enzyme synthesis and enzyme efficiency. The basidiomycete Phanerochaete chrysosporium was grown on the leaves, stems, and roots of maize over 126 days in controlled conditions. We periodically measured the fungal biomass, enzyme activity, and chemical composition of the remaining litter and continuously measured the evolved C-CO2. The CUE observed for the maize litter was highest in the leaves (0.63), intermediate in the roots (0.40), and lowest in the stems (0.38). However, the enzyme efficiency and investment in enzyme synthesis did not follow the same pattern. The amount of litter C decomposed per mole of C-acquiring hydrolase activity was 354 μg C in the leaves, 246 μg C in the roots, and 1541 μg C in the stems (enzyme efficiency: stems > leaves > roots). The fungus exhibited the highest investment in C-acquiring enzyme when grown on the roots and produced 40-80% less enzyme activity when grown on the stems and leaves (investment in enzymes: roots > leaves > stems). The CUE was dependent on the initial availability and replenishment of the soluble substrate fraction with the degradation products. The production of these compounds was either limited because of the low enzyme efficiency, which occurred in the roots, or because of the low investments in enzyme synthesis, which occurred in the stems. Fungal biosynthesis relied on the ability of the fungus to invest in enzyme synthesis and the efficient interactions between the enzymes and

  6. An Extended Decomposed Theory of Planned Behaviour to Predict the Usage Intention of the Electric Car: A Multi-Group Comparison

    National Research Council Canada - National Science Library

    Ingrid Moons; Patrick De Pelsmacker

    2015-01-01

      An Extended Decomposed Theory of Planned Behaviour (DTPB) is developed that integrates emotions towards car driving and electric cars as well as car driving habits of the DTPB, and is empirically validated in a Belgian sample (n = 1023...

  7. MOCVD growth of GaAs on Si using (Al,In) GaAs/GaAs buffer layer

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, K.; Shiba, Y.; Asai, K. (Advanced Tech. Research Labs., Sumitomo Metal Industries, Ltd., Hyogo (Japan))

    1991-01-01

    GaAs was grown on Si using an (Al,In)GaAs/GaAs buffer layer. The etch pit density (EPD) revealed by molten KOH could be reduced by adding Al{sub x}Ga{sub 1-x}As or In{sub x}Ga{sub 1-x}As to the GaAs buffer layer, depending on the composition (x); the lowest EPD, 4x10{sup 6} cm{sup -2} was obtained when x was 0.3 in Al{sub x}Ga{sub 1-x}As. To understand the results, the initial growth stage of GaAs on Si was investigated by scanning electron microscopy. GaAs growth using an Al{sub 0.3}Ga{sub 0.7}As layer produced small islands at a sufficiently high density that the islands coalesced, unlike those without the layer. The dependence of EPD and island density on the composition (x) were almost the same. This result indicates that improvement of the quality of the GaAs layer is related to the coalescence of the GaAs island at an early stage of the growth of GaAs on Si. (orig.).

  8. Fast large scale structure perturbation theory using one-dimensional fast Fourier transforms

    Science.gov (United States)

    Schmittfull, Marcel; Vlah, Zvonimir; McDonald, Patrick

    2016-05-01

    The usual fluid equations describing the large-scale evolution of mass density in the universe can be written as local in the density, velocity divergence, and velocity potential fields. As a result, the perturbative expansion in small density fluctuations, usually written in terms of convolutions in Fourier space, can be written as a series of products of these fields evaluated at the same location in configuration space. Based on this, we establish a new method to numerically evaluate the 1-loop power spectrum (i.e., Fourier transform of the 2-point correlation function) with one-dimensional fast Fourier transforms. This is exact and a few orders of magnitude faster than previously used numerical approaches. Numerical results of the new method are in excellent agreement with the standard quadrature integration method. This fast model evaluation can in principle be extended to higher loop order where existing codes become painfully slow. Our approach follows by writing higher order corrections to the 2-point correlation function as, e.g., the correlation between two second-order fields or the correlation between a linear and a third-order field. These are then decomposed into products of correlations of linear fields and derivatives of linear fields. The method can also be viewed as evaluating three-dimensional Fourier space convolutions using products in configuration space, which may also be useful in other contexts where similar integrals appear.

  9. Intense terahertz emission from molecular beam epitaxy-grown GaAs/GaSb(001)

    Energy Technology Data Exchange (ETDEWEB)

    Sadia, Cyril P.; Laganapan, Aleena Maria; Agatha Tumanguil, Mae; Estacio, Elmer; Somintac, Armando; Salvador, Arnel [National Institute of Physics, University of the Philippines Diliman, Quezon City 1101 (Philippines); Que, Christopher T. [Physics Department, De La Salle University, 2401 Taft Avenue, Manila 1004 (Philippines); Yamamoto, Kohji; Tani, Masahiko [Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507 (Japan)

    2012-12-15

    Intense terahertz (THz) electromagnetic wave emission was observed in undoped GaAs thin films deposited on (100) n-GaSb substrates via molecular beam epitaxy. GaAs/n-GaSb heterostructures were found to be viable THz sources having signal amplitude 75% that of bulk p-InAs. The GaAs films were grown by interruption method during the growth initiation and using various metamorphic buffer layers. Reciprocal space maps revealed that the GaAs epilayers are tensile relaxed. Defects at the i-GaAs/n-GaSb interface were confirmed by scanning electron microscope images. Band calculations were performed to infer the depletion region and electric field at the i-GaAs/n-GaSb and the air-GaAs interfaces. However, the resulting band calculations were found to be insufficient to explain the THz emission. The enhanced THz emission is currently attributed to a piezoelectric field induced by incoherent strain and defects.

  10. A methodical 68Ga-labelling study of DO2A-(butyl-L-tyrosine)2 with cation-exchanger post-processed 68Ga: practical aspects of radiolabelling.

    Science.gov (United States)

    Riss, Patrick J; Burchardt, Carsten; Roesch, Frank

    2011-01-01

    Positron emission tomography (PET) with (68)Ga is a fast-growing field in molecular imaging, both in research and in clinical routine. The availability of (68)Ga via the (68)Ge/(68)Ga radionuclide generator facilitates the development and production of radiopharmaceuticals independent of a cyclotron. The presented work shows a complete (68) Ga labelling study exemplified on [(68)Ga]DO2A-(butyl-L-tyrosine)(2), a potential tumour tracer for PET. A methodical sequence is followed to optimize the (68)Ga-labelling reaction. Practical aspects are described and the different parameters contributing to the labelling yield are demonstrated. The influence of temperature, time, amount of labelling precursor and pH value on the radiochemical yields is demonstrated. A conventional heating method is compared with microwave irradiation as an alternative labelling method. Finally, purification of (68)Ga-labelled compounds via solid-phase extraction and quality control is shown. The procedure described in this manuscript may serve as a guideline for optimizing (68)Ga labelling reactions. Copyright © 2011 John Wiley & Sons, Ltd.

  11. FAST joins Breakthrough programme

    Science.gov (United States)

    Banks, Michael

    2016-11-01

    The 180m Five-hundred-meter Aperture Spherical radio Telescope (FAST) - the world's largest single-aperture radio receiver - has become part of the Breakthrough Listen programme, which launched in July 2015 to look for intelligent life beyond Earth.

  12. CMS Fast Facts

    Data.gov (United States)

    U.S. Department of Health & Human Services — CMS has developed a new quick reference statistical summary on annual CMS program and financial data. CMS Fast Facts includes summary information on total program...

  13. A new fast direct solver for the boundary element method

    Science.gov (United States)

    Huang, S.; Liu, Y. J.

    2017-04-01

    A new fast direct linear equation solver for the boundary element method (BEM) is presented in this paper. The idea of the new fast direct solver stems from the concept of the hierarchical off-diagonal low-rank matrix. The hierarchical off-diagonal low-rank matrix can be decomposed into the multiplication of several diagonal block matrices. The inverse of the hierarchical off-diagonal low-rank matrix can be calculated efficiently with the Sherman-Morrison-Woodbury formula. In this paper, a more general and efficient approach to approximate the coefficient matrix of the BEM with the hierarchical off-diagonal low-rank matrix is proposed. Compared to the current fast direct solver based on the hierarchical off-diagonal low-rank matrix, the proposed method is suitable for solving general 3-D boundary element models. Several numerical examples of 3-D potential problems with the total number of unknowns up to above 200,000 are presented. The results show that the new fast direct solver can be applied to solve large 3-D BEM models accurately and with better efficiency compared with the conventional BEM.

  14. FAST Maser Surveys

    Indian Academy of Sciences (India)

    J. S. Zhang

    2014-09-01

    FAST, the Five-hundred meter Aperture Spherical radio Telescope, will become the largest operating single-dish telescope in the coming years. It has many advantages: much better sensitivity for its largest collecting area; large sky coverage due to its innovative design of the active primary surface; extremely radio quiet from its unique location, etc. In this work, I will highlight the future capabilities of FAST to discover and observe both galactic and extragalactic masers.

  15. Fasting and Urinary Stones

    Directory of Open Access Journals (Sweden)

    Ali Shamsa

    2013-11-01

    Full Text Available Introduction: Fasting is considered as one of the most important practices of Islam, and according to Prophet Mohammad, fasting is obligatory upon Muslims. The aim of this study is to evaluate the effects of fasting on urinary stones. Materials and Methods: Very few studies have been carried out on urinary stones and the effect of Ramadan fasting. The sources of the present study are Medline and articles presented by local and Muslim researchers. Meanwhile, since we are acquainted with three well-known researchers in the field of urology, we contacted them via email and asked for their professional opinions. Results: The results of studies about the relationship of urinary stones and their incidence in Ramadan are not alike, and are even sometimes contradictory. Some believe that increased incidence of urinary stones in Ramadan is related not to fasting, but to the rise of weather temperature in hot months, and an increase in humidity. Conclusion: Numerous biological and behavioral changes occur in people who fast in Ramadan and some researchers believe that urinary stone increases during this month.

  16. Fasting and urinary stones

    Directory of Open Access Journals (Sweden)

    Ali Shamsa

    2013-12-01

    Full Text Available Introduction: Fasting is considered as one of the most important practices of Islam, and according to Prophet Mohammad, fasting is obligatory upon Muslims. The aim of this study is to evaluate the effects of fasting on urinary stones. Materials and Methods:Very few studies have been carried out on urinary stones and the effect of Ramadan fasting. The sources of the present study are Medline and articles presented by local and Muslim researchers. Meanwhile, since we are acquainted with three well-known researchers in the field  of urology, we contacted them via email and asked for their professional opinions. Results:The results of studies about the relationship of urinary stones and their incidence in Ramadan are not alike, and are even sometimes contradictory. Some believe that increased incidence of urinary stones in Ramadan is related not to fasting, but to the rise of weather temperature in hot months, and an increase in humidity. Conclusion: Numerous biological and behavioral changes occur in people who fast in Ramadan and some researchers believe that urinary stone increases during this month.

  17. Preparation and properties of gallaborane, GaBH(6): structure of the gaseous molecule H(2)Ga(mu-H)(2)BH(2) as determined by vibrational, electron diffraction, and ab initio studies, and structure of the crystalline solid at 110 K as determined by X-ray diffraction.

    Science.gov (United States)

    Downs, A J; Greene, T M; Johnsen, E; Brain, P T; Morrison, C A; Parsons, S; Pulham, C R; Rankin, D W; Aarset, K; Mills, I M; Page, E M; Rice, D A

    2001-07-02

    Gallaborane (GaBH(6), 1), synthesized by the metathesis of LiBH(4) with [H(2)GaCl](n) at ca. 250 K, has been characterized by chemical analysis and by its IR and (1)H and (11)B NMR spectra. The IR spectrum of the vapor at low pressure implies the presence of only one species, viz. H(2)Ga(mu-H)(2)BH(2), with a diborane-like structure conforming to C(2v) symmetry. The structure of this molecule has been determined by gas-phase electron diffraction (GED) measurements afforced by the results of ab initio molecular orbital calculations. Hence the principal distances (r(alpha) in A) and angles ( angle(alpha) in deg) are as follows: r(Ga.B), 2.197(3); r(Ga-H(t)), 1.555(6); r(Ga-H(b)), 1.800(6); r(B-H(t)), 1.189(7); r(B-H(b)), 1.286(7); angleH(b)-Ga-H(b), 71.6(4); and angleH(b)-B-H(b), 110.0(5) (t = terminal, b = bridging). Aggregation of the molecules occurs in the condensed phases. X-ray crystallographic studies of a single crystal at 110 K reveal a polymeric network with helical chains made up of alternating pseudotetrahedral GaH(4) and BH(4) units linked through single hydrogen bridges; the average Ga.B distance is now 2.473(7) A. The compound decomposes in the condensed phases at temperatures exceeding ca. 240 K with the formation of elemental Ga and H(2) and B(2)H(6). The reactions with NH(3), Me(3)N, and Me(3)P are also described.

  18. Recombination dynamics of type-II excitons in (Ga,In)As/GaAs/Ga(As,Sb) heterostructures

    Science.gov (United States)

    Gies, S.; Holz, B.; Fuchs, C.; Stolz, W.; Heimbrodt, W.

    2017-01-01

    (Ga,In)As/GaAs/Ga(As,Sb) multi-quantum well heterostructures have been investigated using continuous wave and time-resolved photoluminescence spectroscopy at various temperatures. A complex interplay was observed between the excitonic type-II transitions with electrons in the (Ga,In)As well and holes in the Ga(As,Sb) well and the type-I excitons in the (Ga,In)As and Ga(As,Sb) wells. The type-II luminescence exhibits a strongly non-exponential temporal behavior below a critical temperature of T c = 70 K. The transients were analyzed in the framework of a rate-equation model. It was found that the exciton relaxation and hopping in the localized states of the disordered ternary Ga(As,Sb) are the decisive processes to describe the dynamics of the type-II excitons correctly.

  19. Adsorption of SF6 decomposed gas on anatase (101) and (001) surfaces with oxygen defect: a density functional theory study.

    Science.gov (United States)

    Zhang, Xiaoxing; Chen, Qinchuan; Tang, Ju; Hu, Weihua; Zhang, Jinbin

    2014-04-23

    The detection of partial discharge by analyzing the components of SF6 gas in gas-insulated switchgears is important to the diagnosis and assessment of the operational state of power equipment. A gas sensor based on anatase TiO2 is used to detect decomposed gases in SF6. In this paper, first-principle density functional theory calculations are adopted to analyze the adsorption of SO2, SOF2, and SO2F2, the primary decomposition by-products of SF6 under partial discharge, on anatase (101) and (001) surfaces. Simulation results show that the perfect anatase (001) surface has a stronger interaction with the three gases than that of anatase (101), and both surfaces are more sensitive and selective to SO2 than to SOF2 and SO2F2. The selection of a defect surface to SO2, SOF2, and SO2F2 differs from that of a perfect surface. This theoretical result is corroborated by the sensing experiment using a TiO2 nanotube array (TNTA) gas sensor. The calculated values are analyzed to explain the results of the Pt-doped TNTA gas sensor sensing experiment. The results imply that the deposited Pt nanoparticles on the surface increase the active sites of the surface and the gas molecules may decompose upon adsorption on the active sites.

  20. Applying Decomposed Theory of Planned Behaviour towards a Comprehensive Understanding of Social Network Usage in Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Waleed A. Al-Ghaith

    2016-05-01

    Full Text Available This study examines the individuals‟ participation intentions and behaviour on Social Networking Sites. For this purpose, the Decomposed Theory of Planned Behaviour is utilized. Data collected from a survey of 1100 participants and distilled to 657 usable sets has been analysed to assess the predictive power of Decomposed Theory of Planned Behaviour‟ model via structural equation modelling. The results show that attitude and subjective norm have significant effect on the participation intention of adopters. Further, the results show that participation intention has significant effect on participation behaviour. However, the study findings also show that perceived behavioural control has no significant effect on participation intention or behaviour of adopters. The model adopted in this study explains 47% of the variance in “Participation Intentions” and 36% of the variance in “Participation Behaviour”. Participation of behavioural intention in the model‟ explanatory power was the highest amongst the constructs (able to explain 14.6% of usage behaviour. While, “attitude” explain around 9% of SNSs usage behaviour

  1. Can organic matter hide from decomposers in the labyrinth of soil aggregates? Micro-engineered Soil Chips challenging foraging fungi

    Science.gov (United States)

    Hammer, Edith C.; Aleklett, Kristin; Arellano Caicedo, Carlos G.; Bengtsson, Martin; Micaela Mafla Endara, Paola; Ohlsson, Pelle

    2017-04-01

    From the point of view of microorganisms, the soil environment is an enormously complex labyrinth with paths and dead-end streets, where resources and shelters are unevenly distributed. We study foraging strategies of soil organisms, especially fungi, and the possibility of physio-spatial stabilization of organic matter by "hiding" in occluded soil spaces. We manipulate growth habitat microstructure with lab-on-a-chip techniques, where we designed complex environments with channels and obstacle at dimensions of the size of hyphae, and construct them in the transparent, gas-permeable polymer PDMS. We fill those with different nutrient solutions or combine with mineral nutrient gradients, and inoculate them with soil organisms. We analyze organisms and substrates with microscopy, fluorescence microscopy and analytical chemistry. We compared different soil litter decomposers and an arbuscular mycorrhizal fungus for their ability to forage through complex air-gap structures and attempt to classify them into functional traits concerning their mycelium directionality, space-exploring approach and ability to grow through acute angles and narrow constrictions. We identified structures which are very difficult to penetrate for most species, and compounds located behind such features may thus be spatially unavailable for decomposers. We discuss our approach in comparison to soil pore space tomographic analyses and findings we made in the pore space of colonized wood biochar.

  2. Application of supercritical water to decompose brominated epoxy resin and environmental friendly recovery of metals from waste memory module.

    Science.gov (United States)

    Li, Kuo; Xu, Zhenming

    2015-02-03

    Waste Memory Modules (WMMs), a particular kind of waste printed circuit board (WPCB), contain a high amount of brominated epoxy resin (BER), which may bring a series of environmental and health problems. On the other hand, metals like gold and copper are very valuable and are important to recover from WMMs. In the present study, an effective and environmental friendly method using supercritical water (SCW) to decompose BER and recover metals from WMMs was developed instead of hydrometallurgy or pyrometallurgy simultaneously. Experiments were conducted under external-catalyst-free conditions with temperatures ranging from 350 to 550 °C, pressures from 25 to 40 MPa, and reaction times from 120 to 360 min in a semibatch-type reactor. The results showed that BER could be quickly and efficiently decomposed under SCW condition, and the mechanism was possibly free radical reaction. After the SCW treatments, the glass fibers and metal foils in the solid residue could be easily liberated and recovered, respectively. The metal recovery rate reached 99.80%. The optimal parameters were determined as 495 °C, 33 MPa, and 305 min on the basis of response surface methodology (RSM). This study provides an efficient and environmental friendly approach for WMMs recycling compared with electrolysis, pyrometallurgy, and hydrometallurgy.

  3. Stimulatory effects of biosurfactant produced by Pseudomonas aeruginosa BSZ-07 on rice straw decomposing[G1

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qiuzhuo; CAI Weimin; WANG Juan

    2008-01-01

    Biosurfactant, produced by Pseudomonas aeruginosa BSZ-07, was added to the rice straw decomposing process to enhance the production of reducing sugars. Observed by Fourier Transform InfraRed (FT-IR) and Nuclear Magnetic Resonance [G2](NMR) analysis, the purified biosurfactant was considered as a mixture of RL1 and RL2, which are two different types of rhamnolipids. Two different adding methods, adding the purified rhamnolipid and the on-site production of it were compared. The results showed that 0.5 g/L was the optimum concentration for adding purified rhamnolipid and the optimum temperature for on-site production was 30℃ for the first 48 h and 34℃ for the next 48 h. Under the optimum conditions, these two adding methods could improve the production of reducing sugar to 2.730 g/L and 2.504 g/L, which was 22.30% and 12.20% higher than that of the rhamnolipid-free sample, respectively, which indicated that both of them were more effective than any other kind of surfactant discussed in this article. As the on-site production of rhamnolipid could omit the purification process, thus reducing the production cost effectively, it seemed to be a prospective adding method of the biosurfactant for enhancing rice straw decomposing.

  4. High-pressure high-temperature decomposition of CeCoGa to the Laves phases CeCo{sub 0.58}Ga{sub 1.42}, CeCo{sub 0.72}Ga{sub 1.28}, and CeCo{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Niehaus, Oliver; Rodewald, Ute C.; Heying, Birgit; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Heymann, Gunter; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie

    2016-07-01

    The monoclinic intermediate-valent gallide CeCoGa decomposes under high-pressure (HP) (9.5 GPa) high-temperature (HT) (1470 K) conditions into the Laves phases CeCo{sub 0.58}Ga{sub 1.42} (MgCu{sub 2} type), CeCo{sub 0.72}Ga{sub 1.28} (MgZn{sub 2} type; major product phase), and CeCo{sub 2} (MgCu{sub 2} type). The structures of the ternary Laves phases were refined from single crystal X-ray diffractometer data: Fd anti 3m, a=778.3(1) pm, wR2=0.0310, 63 F{sup 2} values, five variables for CeCo{sub 0.58(3)}Ga{sub 1.42(3)} and P6{sub 3}/mmc, a=547.24(5), c=858.76(7) pm, wR2=0.1009, 195 F{sup 2} values, 13 variables for CeCo{sub 0.72(1)}Ga{sub 1.28(1)}. Partial substitution of cobalt by gallium leads to a significant increase of the distances within the tetrahedral network: 253 pm Co-Co in CeCo{sub 2} as compared to 275 pm in CeCo{sub 0.58(3)}Ga{sub 1.42(3)} and 265-277 pm in CeCo{sub 0.72(1)}Ga{sub 1.28(1)}. The crystal chemical consequences are briefly discussed.

  5. Fabrication of GaN-Based Heterostructures with an InAlGaN/AlGaN Composite Barrier

    Institute of Scientific and Technical Information of China (English)

    Ru-Dai Quan; Jin-Cheng Zhang; Jun-Shuai Xue; Yi Zhao; Jing Ning; Zhi-Yu Lin; Ya-Chao Zhang

    2016-01-01

    GaN-based heterostructures with an InAlGaN/AlGaN composite barrier on sapphire (0001) substrates are grown by a low-pressure metal organic chemical vapor deposition system.Compositions of the InAlGaN layer are determined by x-ray photoelectron spectroscopy,structure and crystal quality of the heterostructures are identified by high resolution x-ray diffraction,surface morphology of the samples are examined by an atomic force microscope,and Hall effect and capacitance-voltage measurements are performed at room temperature to evaluate the electrical properties of heterostructures.The Al/In ratio of the InAlGaN layer is 4.43,which indicates that the InAlGaN quaternary layer is nearly lattice-matched to the GaN channel.Capacitance-voltage results show that there is no parasitic channel formed between the InAlGaN layer and the AlGaN layer.Compared with the InAlGaN/GaN heterostructure,the electrical properties of the InAlGaN/AlGaN/GaN heterostructure are improved obviously.Influences of the thickness of the AlGaN layer on the electrical properties of the heterostructures are studied.With the optimal thickness of the AlGaN layer to be 5 nm,the 2DEG mobility,sheet density and the sheet resistance of the sample is 1889.61 cm2/V.s,1.44 × 1013 cm-2 and as low as 201.1 Ω/sq,respectively.

  6. High-resolution mirror temperature mapping in GaN-based diode lasers by thermoreflectance spectroscopy

    Science.gov (United States)

    Pierścińska, Dorota; Marona, Łucja; Pierściński, Kamil; Wiśniewski, Przemysław; Perlin, Piotr; Bugajski, Maciej

    2017-02-01

    In this paper accurate measurements of temperature distribution on the facet of GaN-based diode lasers are presented as well as development of the instrumentation for high-resolution thermal imaging based on thermoreflectance. It is shown that thermoreflectance can be successfully applied to provide information on heat dissipation in these devices. We demonstrate the quantitative measurements of the temperature profiles and high-resolution temperature maps on the front facet of nitride lasers and prove that thermoreflectance spectroscopy can be considered as the accurate and fast nondestructive tool for investigation of thermally induced degradation modes of GaN lasers.

  7. Structure of {sup 81}Ga populated from the {beta}{sup -} decay of {sup 81}Zn

    Energy Technology Data Exchange (ETDEWEB)

    Paziy, V.; Mach, H.; Fraile, L. M.; Olaizola, B.; Udias, J. M. [Grupo de Fisica Nuclear, Universidad Complutense, Madrid (Spain); Aprahamian, A.; Bucher, B. [Department of Physics, University of Notre Dame (United States); Bernards, C. [Institut fuer Kernphysik, Koeln, Germany. and Wright Nuclear Structure Laboratory, Yale University, New Haven, CT-06520 (United States); Briz, J. A. [Instituto de Estructura de la Materia, CSIC, Madrid (Spain); Chiara, C. J. [Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, USA. and Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Dlouhy, Z. [Nuclear Physics Institute of the ASCR, Rez (Czech Republic); Gheorghe, I.; Ghita, D.; Lica, R.; Marginean, N.; Marginean, R.; Stanoiu, M.; Stroe, L. [National Institute for Physics and Nuclear Engineering, Magurele (Romania); Hoff, P. [Department of Chemistry, University of Oslo, Oslo (Norway); Koester, U. [Institut Laue Langevin, 6 Rue Jules Horowitz, F-38042 Grenoble Cedex 9 (France); and others

    2013-06-10

    We report on the results of the {beta}-decay of {sup 81}Zn. The experiment was performed at the CERN ISOLDE facility in the framework of a systematic ultra-fast timing investigation of neutron-rich nuclei populated in the decay of Zn. The present analysis included {beta}-gated {gamma}-ray singles and {gamma}-{gamma} coincidences from the decay of {sup 81}Zn to {sup 81}Ga and leads to a new and much more extensive level scheme of {sup 81}Ga. A new half-life of {sup 81}Zn is provided.

  8. Investigation of InAs/GaSb-based superlattices by diffraction methods

    Energy Technology Data Exchange (ETDEWEB)

    Ashuach, Y.; Kauffmann, Y.; Lakin, E. [Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Zolotoyabko, E., E-mail: zloto@tx.technion.ac.i [Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Grossman, S.; Klin, O.; Weiss, E. [SCD, SemiConductor Devices, P. O. Box 2250, Haifa 31021 (Israel)

    2010-02-15

    We use high-resolution X-ray diffraction and high-resolution transmission electron microscopy in order to study the strain state, atomic intermixing and layer thicknesses in the MBE-grown GaSb/InSb/InAs/InSb superlattices. Simple and fast metrology procedure is developed, which allows us to obtain the most important technological parameters, such as the thicknesses of the GaSb, InAs and ultra-thin InSb sub-layers, the superlattice period and the fraction of atomic substitutions in the InSb sub-layers.

  9. Excitonic optical nonlinearities and transport in the layered compound semiconductor GaSe

    DEFF Research Database (Denmark)

    Mizeikis, V.; Vadim, Lyssenko; Østergaard, John Erland;

    1995-01-01

    Dephasing and transient grating experiments in the direct excitonic absorption region of GaSe at low temperatures show that a fast relaxation within the one-dimensionally disordered excitonic band results in band filling being the dominant mechanism of the optical nonlinearity. Correspondingly, we...... observe a blueshift of the nonlinear signal with excitation density. The temperature dependence of the exciton diffusion constant measured in directions parallel to the GaSe layer planes indicates that temperature-independent scattering (trapping) and scattering by acoustic phonons determine the exciton...

  10. Micromechanical sensors based on GaAs/AlGaAs

    OpenAIRE

    Fricke, K; Dehe, A.; SchuBler, M; Lee, W.Y.; Hartnagel, H.L.

    1994-01-01

    The combination of high temperature stable electro­nics with micromachining is a powerful means to de­velop a variety of intelligent sensors. Especially in the GaAs/AlGaAs material system all advantages fit to­gether to realize micromachined sensors with integrated high temperature electronics. The technology includes new ohmic and Schottky contacts with high stability at increased ambient temperature. A thermal sensor is pre­sented that can detect total pressure, gas type as well as gas velo...

  11. Optimized production and quality control of (68)Ga-EDTMP for small clinical trials.

    Science.gov (United States)

    Mirzaei, Alireza; Jalilian, Amir R; Badbarin, Ali; Mazidi, Mohammad; Mirshojaei, Fatemeh; Geramifar, Parham; Beiki, Davood

    2015-07-01

    Optimized production and quality control of gallium-68 labeled ethylenediamine tetramethylene phosphonate ((68)Ga-EDTMP) as an efficient PET radiotracer for bone scans have been presented. Efforts have been made to present a fast, efficient, cost-effective and facile protocol for (68)Ga-EDTMP productions for clinical trials. (68)Ga-EDTMP was prepared using generator-based (68)GaCl3 and EDTMP at optimized conditions for time, temperature, ligand amount, gallium content followed by proper formulation. The biodistribution of the tracer in rats was studied using tissue counting and PET/CT imaging up to 155 min. (68)Ga-EDTMP was prepared at optimized conditions in 5-10 min at 50-60 °C (radiochemical purity ≈99 ± 0.88 % ITLC, >99 % HPLC, specific activity: 15-18 GBq/mM). The biodistribution of the tracer demonstrated high bone uptake of the tracer in 10-20 min while yielding the best images in 2 h. The whole production and quality control of (68)Ga-EDTMP including labeling, purification, HPLC analysis, sterilization and LAL test took 18-20 min with significant specific activity for administration to limited number of patients in a PET center.

  12. Electrical Characteristics of InGaN/AlGaN and InGaN/GaN MQW Near UV-LEDs

    Institute of Scientific and Technical Information of China (English)

    MU Sen; YU Tong-Jun; HUANG Liu-Bing; JIA Chuan-Yu; PAN Yao-Bo; YANG Zhi-Jian; CHEN Zhi-Zhong; QIN Zhi-Xin; ZHANG Guo-Yi

    2007-01-01

    Electrical characteristics of Ino.05Gao.95N/AJo.07Gao.93N and Ino.05Gao.95N/GaN multiple quantum well (MQW) ultraviolet light-emitting diodes (UV-LEDs) at 400 nm wavelength are measured. It is found that for In-GaN/AlGaN MQW LEDs, both ideality factor and parallel resistance are similar to those of InGaN/GaN MQW LEDs, while series resistance is two times larger. It is suggested that the AJ0.07Ga0.93N barrier layer did not change crystal quality and electrical characteristic ofp-n junction either, but brought larger series resistance. As a result, InGaN/AlGaN MQW LEDs suffer more serious thermal dissipation problem although they show higher light output efficiency.

  13. Convenient preparation of 68Ga-based PET-radiopharmaceuticals at room temperature.

    Science.gov (United States)

    Velikyan, I; Maecke, H; Langstrom, B

    2008-02-01

    A straightforward labeling using generator produced positron emitting (68)Ga, which provides high quality images, may result in kit type production of PET radiopharmaceuticals and make PET examinations possible also at centers lacking accelerators. The introduction of macrocyclic bifunctional chelators that would provide fast (68)Ga-complexation at room temperature would simplify even further tracer preparation and open wide possibilities for (68)Ga-labeling of fragile and potent macromolecules. Gallium-68 has the potential to facilitate development of clinically practical PET and to promote PET technique for individualized medicine. The macrocyclic chelator, 1,4,7-triazacyclononanetriacetic acid (NOTA), and its derivative coupled to an eight amino acid residue peptide (NODAGA-TATE, [NODAGA (0), Tyr(3)]Octreotate) were labeled with (68)Ge/(68)Ga-generator produced positron emitting (68)Ga. Formation kinetics of (68)Ga-NOTA was studied as a function of pH and formation kinetics of (68)Ga-NODAGA-TATE was studied as a function of the bioconjugate concentration. The nearly quantitative radioactivity incorporation (RAI>95%) for (68)Ga-NOTA was achieved within less than 10 min at room temperature and pH 3.5. The concentrations of NODAGA-TATE required for RAI of >90% and >95% were, respectively, 2-5 and 10 microM. In both cases the purification of the (68)Ga-labeled products was not necessary since the radiochemical purity was >95% and the preparation buffer, 4-(2-hydroxyethyl) piperazine-1-ethanesulfonic acid (HEPES) is suitable for human use. In order to confirm the identity of the products, complexes comprising (nat)Ga were synthesized and analyzed by mass spectrometry. The complex was found to be stable in the reaction mixture, phosphate buffer, and human plasma during 4.5 h incubation. Free and peptide conjugated NOTA formed stable complexes with (68)Ga at room temperature within 10 min. This might be of special interest for the labeling of fragile and potent

  14. Thermal diffusion of Mn through GaAs overlayers on (Ga, Mn)As

    Energy Technology Data Exchange (ETDEWEB)

    Adell, J; Ulfat, I; Ilver, L; Kanski, J [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Gothenburg (Sweden); Sadowski, J [Institute of Physics, Polish Academy of Sciences, PL-02-668 Warsaw (Poland); Karlsson, K [Department of Life Sciences, University of Skoevde, SE-541 28 Skoevde (Sweden)

    2011-03-02

    Thermally stimulated diffusion of Mn through thin layers of GaAs has been studied by x-ray photoemission. (Ga, Mn)As samples with 5 at% Mn were capped with 4, 6 and 8 monolayer (ML) GaAs, and Mn diffusing through the GaAs was trapped on the surface by means of amorphous As. It was found that the out-diffusion is completely suppressed for an 8 ML thick GaAs film. The short diffusion length is attributed to an electrostatic barrier formed at the (Ga, Mn)As/GaAs interface.

  15. Multilayers of InGaAs Nanostructures Grown on GaAs(210 Substrates

    Directory of Open Access Journals (Sweden)

    Wang Zhiming

    2010-01-01

    Full Text Available Abstract Multilayers of InGaAs nanostructures are grown on GaAs(210 by molecular beam epitaxy. With reducing the thickness of GaAs interlayer spacer, a transition from InGaAs quantum dashes to arrow-like nanostructures is observed by atomic force microscopy. Photoluminescence measurements reveal all the samples of different spacers with good optical properties. By adjusting the InGaAs coverage, both one-dimensional and two-dimensional lateral ordering of InGaAs/GaAs(210 nanostructures are achieved.

  16. Thermal diffusion of Mn through GaAs overlayers on (Ga, Mn)As.

    Science.gov (United States)

    Adell, J; Ulfat, I; Ilver, L; Sadowski, J; Karlsson, K; Kanski, J

    2011-03-02

    Thermally stimulated diffusion of Mn through thin layers of GaAs has been studied by x-ray photoemission. (Ga, Mn)As samples with 5 at% Mn were capped with 4, 6 and 8 monolayer (ML) GaAs, and Mn diffusing through the GaAs was trapped on the surface by means of amorphous As. It was found that the out-diffusion is completely suppressed for an 8 ML thick GaAs film. The short diffusion length is attributed to an electrostatic barrier formed at the (Ga, Mn)As/GaAs interface.

  17. InGaAs/GaAs异质薄膜的MBE生长研究%The MBE growth research on InGaAs/GaAs heterofilms

    Institute of Scientific and Technical Information of China (English)

    罗子江; 周勋; 杨再荣; 贺业全; 何浩; 邓朝勇; 丁召

    2011-01-01

    This paper reports an experiment research which utilized of the molecular beam epitaxy technology to grow the InGaAs/GaAs film. The growth conditions was monitored through the RHEED patterns in real-time,the growth rate was measured and the composition of InGaAs film was determined by RHEED intensity oscillations,and a method was put forward to control the composition of In/Ga in InGaAs/GaAs film. According to the R HEED patterns, the surface of InGaAs film was (2 × 3) reconstructed. After growth, the sample was quenched down to room temperature then transferred into STM for scanning. A smooth,atomically flat surface of InGaAs/GaAs film was confirmed by the STM images.%利用分子束外延技术,在GaAs(001)基片上外延InGaAs/GaAs异质薄膜,通过RHEED图像演变实时监控薄膜生长状况,采用RHEED强度振荡测量薄膜生长速率,确定薄膜中In/Ga的组分比,并提出控制InGaAs薄膜中In/Ga组分比的生长方法.根据RHEED图像,指出获得的InGaAs薄膜处于(2×3)表面重构相.样品经过淬火至室温后对样品做STM扫描分析,证实样品为表面原子级平整的InGaAs/GaAs异质薄膜.

  18. Thermal Stability of Strained AlGaN/GaN Heterostructures

    Institute of Scientific and Technical Information of China (English)

    ZHANG Min; XIAO Hong-Di; LIN Zhao-Jun

    2006-01-01

    @@ The thermal stability of strained AlGaN/GaN heterostructures is characterized by comparing unannealed and 700℃ 30-min annealed Ni Schottky contacts prepared on strained AlGaN/GaN heterostructures. Using photoemission, capacitance-voltage measurements, and the self-consistent solution of Schrodinger's and Poisson's equations, it is found that after 700℃ 30-min thermal annealing the Schottky barrier height of Ni Schottky contacts on strained AlGaN/GaN heterostructures is increased, and the sheet density of polarization charges and the sheet density of two-dimensional electron gas (2DEG) electrons for the strained AlGaN/GaN heterostructures are reduced. These results are closely related to the performance of AlGaN/GaN HFETs at high temperature.

  19. Technology of integrated self-aligned E/D-mode n++GaN/InAlN/AlN/GaN MOS HEMTs for mixed-signal electronics

    Science.gov (United States)

    Blaho, M.; Gregušová, D.; Haščík, Š.; Seifertová, A.; Ťapajna, M.; Šoltýs, J.; Šatka, A.; Nagy, L.; Chvála, A.; Marek, J.; Carlin, J.-F.; Grandjean, N.; Konstantinidis, G.; Kuzmík, J.

    2016-06-01

    We describe the technology and performance of integrated enhancement/depletion (E/D)-mode n++GaN/InAlN/AlN/GaN HEMTs with a self-aligned metal-oxide-semiconductor (MOS) gate structure. An identical starting epi-structure was used for both types of devices without the additional need for a contacts regrowth. The n++GaN cap layer was etched away in the gate trenches of the E-mode HEMT while it was left intact for the D-mode HEMT. The plasma etching process was shown to be highly selective between the cap and the InAlN barrier and also to polish the InAlN surface. However, different GaN etching initiation times inside and outside the mesa region were obtained. Gate contacts were isolated using a dielectric layer deposited at low temperature through an e-beam resist to retain the self-aligned approach. Feasibility of the approach for future fast GaN-based mixed-signal electronic circuits was shown by obtaining alternative HEMT threshold voltage values of +0.8 V and -2.6 V, invariant maximal output current of ˜0.35 A mm-1 despite large source-to-drain distances and by demonstrating a functional logic invertor.

  20. Development of GaN/AlGaN Terahertz Quantum Cascade Laser

    Science.gov (United States)

    2008-11-19

    AFOSR-Taiwan Nanoscience Initiative Project Final Report Project Title Development of GaN /AlGaN Terahertz Quantum Cascade Laser...DATES COVERED 14-06-2007 to 13-06-2008 4. TITLE AND SUBTITLE Development of GaN -Based Terahertz Quantum Cascade Laser 5a. CONTRACT NUMBER...the GaN /AlGaN active region for terahertz quantum cascade lasers using MOCVD system based on the quantum cascade structure proposed by Prof. Greg Sun

  1. The fast code

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, L.N.; Wilson, R.E. [Oregon State Univ., Dept. of Mechanical Engineering, Corvallis, OR (United States)

    1996-09-01

    The FAST Code which is capable of determining structural loads on a flexible, teetering, horizontal axis wind turbine is described and comparisons of calculated loads with test data are given at two wind speeds for the ESI-80. The FAST Code models a two-bladed HAWT with degrees of freedom for blade bending, teeter, drive train flexibility, yaw, and windwise and crosswind tower motion. The code allows blade dimensions, stiffnesses, and weights to differ and models tower shadow, wind shear, and turbulence. Additionally, dynamic stall is included as are delta-3 and an underslung rotor. Load comparisons are made with ESI-80 test data in the form of power spectral density, rainflow counting, occurrence histograms, and azimuth averaged bin plots. It is concluded that agreement between the FAST Code and test results is good. (au)

  2. A fast friend

    Institute of Scientific and Technical Information of China (English)

    高怡

    2010-01-01

    我们都知道fast food的意思是“快餐”。那fast friend能解释为“快速或速成的朋友”吗?也许你会说:“什么是速成朋友呀?It doesn’t make sense.”没错,交朋友怎么会有速成的呢?原来;fast还有一个意思是“忠实的、牢固的”,所以a fast friend的真正意思是“可靠、忠实的朋友”。

  3. Fast Distributed Gradient Methods

    CERN Document Server

    Jakovetic, Dusan; Moura, Jose M F

    2011-01-01

    The paper proposes new fast distributed optimization gradient methods and proves convergence to the exact solution at rate O(\\log k/k), much faster than existing distributed optimization (sub)gradient methods with convergence O(1/\\sqrt{k}), while incurring practically no additional communication nor computation cost overhead per iteration. We achieve this for convex (with at least one strongly convex,) coercive, three times differentiable and with Lipschitz continuous first derivative (private) cost functions. Our work recovers for distributed optimization similar convergence rate gains obtained by centralized Nesterov gradient and fast iterative shrinkage-thresholding algorithm (FISTA) methods over ordinary centralized gradient methods. We also present a constant step size distributed fast gradient algorithm for composite non-differentiable costs. A simulation illustrates the effectiveness of our distributed methods.

  4. Chemistry and electrical properties of surfaces of GaN and GaN/AlGaN heterostructures

    OpenAIRE

    Hashizume, Tamotsu; Ootomo, Shinya; Oyama, Susumu; Konishi, Masanobu; Hasegawa, Hideki

    2001-01-01

    Chemical and electrical properties of the surfaces of GaN and GaN/AlGaN heterostructures were systematically investigated by x-ray photoelectron spectroscopy (XPS), capacitance–voltage, and current–voltage measurements. From in situ XPS study, relatively smaller band bending of 0.6 eV was seen at the GaN (2×2) surface grown by radio frequency-assisted molecular beam epitaxy on the metalorganic vapor phase epitaxy GaN template. After exposing the sample surface to air, strong band bending took...

  5. InGaN/GaN Tunnel Junctions For Hole Injection in GaN Light Emitting Diodes

    OpenAIRE

    Krishnamoorthy, Sriram; Akyol, Fatih; Rajan, Siddharth

    2014-01-01

    InGaN/GaN tunnel junction contacts were grown on top of an InGaN/GaN blue (450 nm) light emitting diode wafer using plasma assisted molecular beam epitaxy. The tunnel junction contacts enable low spreading resistance n-GaN top contact layer thereby requiring less top metal contact coverage on the surface. A voltage drop of 5.3 V at 100 mA, forward resistance of 2 x 10-2 ohm cm2 and a higher light output power are measured in tunnel junction LED. A low resistance of 5 x 10-4 ohm cm2 was measur...

  6. AlGaN/GaN High Electron Mobility Transistors with Multi-MgxNy/GaN Buffer

    Directory of Open Access Journals (Sweden)

    P. C. Chang

    2014-01-01

    Full Text Available We report the fabrication of AlGaN/GaN high electron mobility transistors with multi-MgxNy/GaN buffer. Compared with conventional HEMT devices with a low-temperature GaN buffer, smaller gate and source-drain leakage current could be achieved with this new buffer design. Consequently, the electron mobility was larger for the proposed device due to the reduction of defect density and the corresponding improvement of crystalline quality as result of using the multi-MgxNy/GaN buffer.

  7. Utilisation of GaN and InGaN/GaN with nanoporous structures for water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Benton, J.; Bai, J.; Wang, T., E-mail: t.wang@sheffield.ac.uk [Department of Electronic and Electrical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2014-12-01

    We report a cost-effective approach to the fabrication of GaN based nanoporous structure for applications in renewable hydrogen production. Photoelectrochemical etching in a KOH solution has been employed to fabricate both GaN and InGaN/GaN nanoporous structures with pore sizes ranging from 25 to 60 nm, obtained by controlling both etchant concentration and applied voltage. Compared to as-grown planar devices the nanoporous structures have exhibited a significant increase of photocurrent with a factor of up to four times. An incident photon conversion efficiency of up to 46% around the band edge of GaN has been achieved.

  8. Temperature coefficients for GaInP/GaAs/GaInNAsSb solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Aho, Arto; Isoaho, Riku; Tukiainen, Antti; Polojärvi, Ville; Aho, Timo; Raappana, Marianna; Guina, Mircea [Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, FIN-33101 Tampere (Finland)

    2015-09-28

    We report the temperature coefficients for MBE-grown GaInP/GaAs/GaInNAsSb multijunction solar cells and the corresponding single junction sub-cells. Temperature-dependent current-voltage measurements were carried out using a solar simulator equipped with a 1000 W Xenon lamp and a three-band AM1.5D simulator. The triple-junction cell exhibited an efficiency of 31% at AM1.5G illumination and an efficiency of 37–39% at 70x real sun concentration. The external quantum efficiency was also measured at different temperatures. The temperature coefficients up to 80°C, for the open circuit voltage, the short circuit current density, and the conversion efficiency were determined to be −7.5 mV/°C, 0.040 mA/cm{sup 2}/°C, and −0.09%/°C, respectively.

  9. Polarization-induced Zener tunnel diodes in GaN/InGaN/GaN heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Xiaodong; Li, Wenjun; Islam, S. M.; Pourang, Kasra; Fay, Patrick [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Xing, Huili; Jena, Debdeep, E-mail: djena@cornell.edu [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Departments of ECE and MSE, Cornell University, Ithaca, New York 14853 (United States)

    2015-10-19

    By the insertion of thin In{sub x}Ga{sub 1−x}N layers into Nitrogen-polar GaN p-n junctions, polarization-induced Zener tunnel junctions are studied. The reverse-bias interband Zener tunneling current is found to be weakly temperature dependent, as opposed to the strongly temperature-dependent forward bias current. This indicates tunneling as the primary reverse-bias current transport mechanism. The Indium composition in the InGaN layer is systematically varied to demonstrate the increase in the interband tunneling current. Comparing the experimentally measured tunneling currents to a model helps identify the specific challenges in potentially taking such junctions towards nitride-based polarization-induced tunneling field-effect transistors.

  10. Fast ejendom II

    DEFF Research Database (Denmark)

    Munk-Hansen, Carsten

    Fremstillingen påviser, at lov om forbrugerbeskyttelse ved erhvervelse af fast ejendom mv. lider af en række svagheder og at ankenævnspraksis bevæger sig væk fra retspraksis på en række områder.......Fremstillingen påviser, at lov om forbrugerbeskyttelse ved erhvervelse af fast ejendom mv. lider af en række svagheder og at ankenævnspraksis bevæger sig væk fra retspraksis på en række områder....

  11. Moms og fast ejendom

    DEFF Research Database (Denmark)

    Edlund, Hans Henrik

    1999-01-01

    I artiklen gives et overblik over, hvorledes fast ejendom behandles momsmæssigt. Derfor findes en kort skitsering af reglerne for moms på byggearbejder, afgrænsningen mellem momspligtig og momsfri udlejning, muligheden for frivillig registrering af udlejning samt opgørelse af reguleringsforpligte......I artiklen gives et overblik over, hvorledes fast ejendom behandles momsmæssigt. Derfor findes en kort skitsering af reglerne for moms på byggearbejder, afgrænsningen mellem momspligtig og momsfri udlejning, muligheden for frivillig registrering af udlejning samt opgørelse af...

  12. Fast Josephson vortex

    Energy Technology Data Exchange (ETDEWEB)

    Malishevskii, A.S.; Silin, V.P.; Uryupin, S.A

    2002-12-30

    For the magnetically coupled waveguide and long Josephson junction we gave the analytic description of two separate velocity domains where the free motion of traveling vortex (2{pi}-kink) exists. The role of the mutual influence of waveguide and long Josephson junction is discussed. It is shown the possibility of the fast vortex motion with the velocity much larger than Swihart velocity of Josephson junction and close to the speed of light in the waveguide. The excitation of motion of such fast Josephson vortex is described.

  13. ATLAS fast physics monitoring

    Indian Academy of Sciences (India)

    Karsten Köneke; on behalf of the ATLAS Collaboration

    2012-11-01

    The ATLAS experiment at the Large Hadron Collider is recording data from proton–proton collisions at a centre-of-mass energy of 7 TeV since the spring of 2010. The integrated luminosity has grown nearly exponentially since then and continues to rise fast. The ATLAS Collaboration has set up a framework to automatically process the rapidly growing dataset and produce performance and physics plots for the most interesting analyses. The system is designed to give fast feedback. The histograms are produced within hours of data reconstruction (2–3 days after data taking). Hints of potentially interesting physics signals obtained this way are followed up by physics groups.

  14. GaAsP/InGaP heterojunction bipolar transistors grown by MOCVD

    Science.gov (United States)

    Heidelberger, Christopher; Fitzgerald, Eugene A.

    2017-01-01

    Heterojunction bipolar transistors with GaAsxP1-x bases and collectors and InyGa1-yP emitters were grown on GaAs substrates via metalorganic chemical vapor deposition, fabricated using conventional techniques, and electrically tested. Four different GaAsxP1-x compositions were used, ranging from x = 0.825 to x = 1 (GaAs), while the InyGa1-yP composition was adjusted to remain lattice-matched to the GaAsP. DC gain close to or exceeding 100 is measured for 60 μm diameter devices of all compositions. Physical mechanisms governing base current and therefore current gain are investigated. The collector current is determined not to be affected by the barrier caused by the conduction band offset between the InGaP emitter and GaAsP base. While the collector current for the GaAs/InGaP devices is well-predicted by diffusion of electrons across the quasi-neutral base, the collector current of the GaAsP/InGaP devices exceeds this estimate by an order of magnitude. This results in higher transconductance for GaAsP/InGaP than would be estimated from known material properties.

  15. Rapid thermal annealing of InAs/GaAs quantum dots under a GaAs proximity cap

    Energy Technology Data Exchange (ETDEWEB)

    Babinski, Adam; Jasinski, J.; Boz(overdot)ek, R.; Szepielow, A.; Baranowski, J. M.

    2001-10-15

    The effect of postgrowth rapid thermal annealing (RTA) on GaAs proximity-capped structures with self-assembled InAs/GaAs quantum dots (QDs) is investigated using transmission electron microscopy (TEM) and photoluminescence (PL). As can be seen from the TEM images, QDs increase their lateral sizes with increasing annealing temperature (up to 700 C). QDs cannot be distinguished after RTA at temperature 800 C or higher, and substantial thickening of the wetting layer can be seen instead. The main PL peak blueshifts as a result of RTA. We propose that in the as-grown sample as well, as in samples annealed at temperatures up to 700 C, the peak is due to the QDs. After RTA at 800 C and higher the PL peak is due to a modified wetting layer. Relatively fast dissolution of QDs is explained in terms of strain-induced lateral Ga/In interdiffusion. It is proposed that such a process may be of importance in proximity-capped RTA, when no group-III vacancy formation takes place at the sample/capping interface.

  16. Contents, accumulation and release of energy in green, dead and decomposing plant materials in an upland grassland near Kamenicky, Czechoslovakia.

    Science.gov (United States)

    Ulehlová, B

    1980-01-01

    The energy content was studied in above-ground live plant material and in litter in a natural grassland ecosystem with dominant Nardus stricta L., defined phytosociologically as Polygalo-Nardetum strictae. PREISING 1950 corr. OBERDORFER 1957, and in two of its fertilized variants in the course of 1975 to 1977. Based on the determined production characteristics and data on decomposition processes, the amounts of energy accumulated by the green parts of the stands and the amount of energy released during decomposition from the litter were calculated. Changes in the energy content of litter in different stages of decomposition were determined. With progressing decomposition the energy content per gram ash-free decomposing plant litter increases.

  17. The algorithm of decomposing superimposed 2-D Poisson processes and its application to the extracting earthquake clustering pattern

    Institute of Scientific and Technical Information of China (English)

    裴韬; 周成虎; 杨明; 骆剑承; 李全林

    2004-01-01

    Aiming at the complexity of seismic gestation mechanism and spatial distribution, we hypothesize that the seismic data are composed of background earthquakes and anomaly earthquakes in a certain temporal-spatial scope. Also the background earthquakes and anomaly earthquakes both satisfy the 2-D Poisson process of different parameters respectively. In the paper, the concept of N-th order distance is introduced in order to transform 2-D superimposed Poisson process into 1-D mixture density function. On the basis of choosing the distance, mixture density function is decomposed to recognize the anomaly earthquakes through genetic algorithm. Combined with the temporal scanning of C value, the algorithm is applied to the recognition on spatial pattern of foreshock anomalies by examples of Songpan and Longling sequences in the southwest of China.

  18. Decorating multiwalled carbon nanotubes with zinc oxide nanoparticles by thermally decomposing Zn-oleate in an organic medium

    Institute of Scientific and Technical Information of China (English)

    LI ChenSha; QIAO YingJie; LI YuNing; WU YiLiang

    2009-01-01

    Carbon nanotubes decorated with zinc oxide nanoparticles were produced by thermally decomposing a Zn-oleate complex in an octadecene medium. The structure of the ZnO decorating nanotube surfaces was characterized by transmission electron microscopy, scanning electron microscopy and X-ray dif-fraction. The surfaces were shown to be densely and homogeneously covered by ZnO nanoparticles with a size below 10 nm. The nanoparticles had the wurtzite hexagonal crystal structure and showed good adhesion to the nanotubes. The carbon nanotubes decorated by metal oxide nanoparticles were synthesized at relatively low temperature and non-oxidation environment. Moreover, the large-scale production with low cost can be realized.

  19. Decorating multiwalled carbon nanotubes with zinc oxide nanoparticles by thermally decomposing Zn-oleate in an organic medium

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Carbon nanotubes decorated with zinc oxide nanoparticles were produced by thermally decomposing a Zn-oleate complex in an octadecene medium.The structure of the ZnO decorating nanotube surfaces was characterized by transmission electron microscopy,scanning electron microscopy and X-ray dif-fraction.The surfaces were shown to be densely and homogeneously covered by ZnO nanoparticles with a size below 10 nm.The nanoparticles had the wurtzite hexagonal crystal structure and showed good adhesion to the nanotubes.The carbon nanotubes decorated by metal oxide nanoparticles were synthesized at relatively low temperature and non-oxidation environment.Moreover,the large-scale production with low cost can be realized.

  20. Litter type affects the activity of aerobic decomposers in a boreal peatland more than site nutrient and water table regimes

    Directory of Open Access Journals (Sweden)

    P. Straková

    2011-09-01

    Full Text Available Peatlands are carbon (C storage ecosystems sustained by a high water table (WT. High WT creates anoxic conditions that suppress the activity of aerobic decomposers and provide conditions for peat accumulation. Peatland function can be dramatically affected by WT drawdown caused by climate and/or land-use change. Aerobic decomposers are directly affected by WT drawdown through environmental factors such as increased oxygenation and nutrient availability. Additionally, they are indirectly affected via changes in plant community composition and litter quality. We studied the relative importance of direct and indirect effects of WT drawdown on aerobic decomposer activity in plant litter at two stages of decomposition (incubated in the field for 1 or 2 years. We did this by profiling 11 extracellular enzymes involved in the mineralization of organic C, nitrogen (N, phosphorus (P and sulphur. Our study sites represented a three-stage chronosequence from pristine to short-term (years and long-term (decades WT drawdown conditions under two nutrient regimes (bog and fen. The litter types included reflected the prevalent vegetation: Sphagnum mosses, graminoids, shrubs and trees.

    Litter type was the main factor shaping microbial activity patterns and explained about 30 % of the variation in enzyme activities and activity allocation. Overall, enzyme activities were higher in vascular plant litters compared to Sphagnum litters, and the allocation of enzyme activities towards C or nutrient acquisition was related to the initial litter quality (chemical composition. Direct effects of WT regime, site nutrient regime and litter decomposition stage (length of incubation period summed to only about 40 % of the litter type effect. WT regime alone explained about 5 % of the variation in enzyme activities and activity allocation. Generally, enzyme activity increased following the long-term WT drawdown and the activity allocation turned from P

  1. Status and Advances of Researches on GA 20-oxidases

    Institute of Scientific and Technical Information of China (English)

    Li Wei; Chen Xiaoyang; Li Hui; Guo Hai

    2003-01-01

    GA 20-oxidase, the most important limiting enzyme, can catalyze a series of oxidization of GA biosynthesis pathwayfrom GA12 to GA9 and from GA53 to GA20 in the higher plants. This paper reviews the studies on the characters of GA 20-oxidase,the gene and the protein of GA 20-oxidase and the regulation of GA 20-oxidase gene expression in recent years. At the same time,the prospects for the gene transformation of GA 20-oxidase in agriculture, forestry and horticulture are also discussed.

  2. How do physicochemical properties influence the toxicity of silver nanoparticles on freshwater decomposers of plant litter in streams?

    Science.gov (United States)

    Batista, Daniela; Pascoal, Cláudia; Cássio, Fernanda

    2017-06-01

    AgNP physicochemical properties may affect AgNP toxicity, but their effects on plant litter decomposition and the species driving this key ecosystem process in freshwaters have been poorly investigated. We assessed the impacts of AgNPs with different size and surface coating (100nm PVP (polyvinylpyrrolidone)-dispersant, 50-60nm and 35nm uncoated) on freshwater decomposers of leaf litter by exposing leaf associated microbial assemblages to increasing concentrations of AgNPs (up to 200mgL(-1)) and of AgNO3 (up to 25mgL(-1)). We further conducted a feeding preference experiment with a common invertebrate shredder, Limnephilus sp., which was allowed to feed on microbially-colonized leaves previously exposed to AgNPs and AgNO3. Leaf decomposition and microbial activity and diversity were inhibited when exposed to increased concentrations of 100nm AgNPs (≥25mgL(-1)), while microbial activity was stimulated by exposure to 35nm AgNPs (≥100mgL(-1)). Invertebrate shredders preferred leaves exposed to 35nm AgNPs (25mgL(-1)) and avoided leaves exposed to AgNO3 (≥2mgL(-1)). Results from the characterization of AgNPs by dynamic light scattering revealed that AgNps with PVP-dispersant were more stable than the uncoated AgNPs. Our results highlight the importance of considering the physicochemical properties of NPs when assessing their toxicity to litter decomposers in freshwaters.

  3. Stoichiometric imbalances between terrestrial decomposer communities and their resources: mechanisms and implications of microbial adaptations to their resources

    Directory of Open Access Journals (Sweden)

    Maria eMooshammer

    2014-02-01

    Full Text Available Terrestrial microbial decomposer communities thrive on a wide range of organic matter types that rarely ever meet their elemental demands. In this review we synthesize the current state-of-the-art of microbial adaptations to resource stoichiometry, in order to gain a deeper understanding of the interactions between heterotrophic microbial communities and their chemical environment. The stoichiometric imbalance between microbial communities and their organic substrates generally decreases from wood to leaf litter and further to topsoil and subsoil organic matter. Microbial communities can respond to these imbalances in four ways: first, they adapt their biomass composition towards their resource in a non-homeostatic behaviour. Such changes are, however, only moderate, and occur mainly because of changes in microbial community structure and less so due to cellular storage of elements in excess. Second, microbial communities can mobilize resources that meet their elemental demand by producing specific extracellular enzymes, which, in turn, is restricted by the C and N requirement for enzyme production itself. Third, microbes can regulate their element use efficiencies (ratio of element invested in growth over total element uptake, such that they release elements in excess depending on their demand (e.g., respiration and N mineralization. Fourth, diazotrophic bacteria and saprotrophic fungi may trigger the input of external N and P to decomposer communities. Theoretical considerations show that adjustments in element use efficiencies may be the most important mechanism by which microbes regulate their biomass stoichiometry. This review summarizes different views on how microbes cope with imbalanced supply of C, N and P, thereby providing a framework for integrating and linking microbial adaptation to resource imbalances to ecosystem scale fluxes across scales and ecosystems.

  4. Low temperature formation of CuIn{sub 1−x}Ga{sub x}Se{sub 2} solar cell absorbers by all printed multiple species nanoparticulate Se + Cu-In + Cu-Ga precursors

    Energy Technology Data Exchange (ETDEWEB)

    Möckel, Stefan A., E-mail: Stefan.A.Moeckel@FAU.de [Department of Materials Science, Chair of Materials for Electronics and Energy Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Martensstr, 7, 91058 Erlangen (Germany); Wernicke, Tobias; Arzig, Matthias; Köder, Philipp [Department of Materials Science, Chair of Materials for Electronics and Energy Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Martensstr, 7, 91058 Erlangen (Germany); Brandl, Marco [Chair for Crystallography and Structural Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstr. 3, 91058 Erlangen (Germany); Ahmad, Rameez; Distaso, Monica; Peukert, Wolfgang [Institute of Particle Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058 Erlangen (Germany); Hock, Rainer [Chair for Crystallography and Structural Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstr. 3, 91058 Erlangen (Germany); Wellmann, Peter J. [Department of Materials Science, Chair of Materials for Electronics and Energy Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Martensstr, 7, 91058 Erlangen (Germany)

    2015-05-01

    In this work an all nanoparticulate precursor for application in Cu(In{sub 1−x}Ga{sub x})Se{sub 2} solar cell absorbers is presented. Binary Cu-In nanoparticles, Cu-Ga powder and elemental Se nanoparticles were mixed in dispersion and deposited on Mo-coated substrates. Research was focused on Cu(In{sub 1−x}Ga{sub x})Se{sub 2} layer formation kinetics, phase composition characterised by differential scanning calorimetry and in-situ X-ray diffraction (XRD). Furthermore phase composition and morphology were studied by ex-situ XRD, Raman spectroscopy and scanning electron microscopy. The results revealed a fast consumption of the precursor and the formation of CuInSe{sub 2} below 340 °C. Binary secondary phases were not observed at any temperature. - Highlights: • All printable precursor for CIGSe • Formation of Ga droplets • Complete consumption below 340 °C.

  5. Adsorption and decomposition mechanism of formic acid on the Ga2O3 surface by first principle studies

    Science.gov (United States)

    Liu, Yan; Li, Zhen Hua

    2017-02-01

    The adsorption and decomposition of formic acid (FA) on the Ga2O3(100) surface was studied with density functional theory. On the perfect Ga2O3(100) surface, the preferred adsorption state of FA is a monodentate configuration while the most stable adsorption state is a bridging configuration. Heating the surface would convert FA from monodentate to bridging configuration and further heating would decompose FA into CO2 and two surface hydroxyl groups. On the other hand, on the O(2)-defect Ga2O3(100) surface the preferred adsorption state of FA is a bridging formate with one O atom of formate filling the O(2) vacancy. Heating the surface would generate CO and two surface hydroxyl groups. If the Ga2O3(100) surface is used as decomposition catalyst, then at low temperature the formation of a small amount of CO2 can be observed. On the other hand, at high temperature continuous formation of CO and H2O can be observed. The active sites for FA decomposition are the O(2) defects on the surface formed in situ from the removal of water from surface hydroxyl groups. The strong dependence of mechanism on experimental conditions explains why no consensus has been reached in the previous experimental studies regarding the adsorption and decomposition mechanism of FA.

  6. Thermodynamics of GaN(s)-NH3(v)+N2(v)+H2(v) system - Electronic aspects of the processes at GaN(0001) surface

    Science.gov (United States)

    Kempisty, Pawel; Strak, Pawel; Sakowski, Konrad; Krukowski, Stanislaw

    2017-08-01

    Comprehensive analysis of GaN(0001) surface in equilibrium with ammonia/hydrogen mixture was undertaken using results of ab initio calculations. Adsorption energies of the species derived from ammonia and molecular hydrogen and their stable sites were obtained. It was shown that the adsorption process type and energy depend on the position of Fermi level at the surface. Hydrogen decomposes into two separate H atoms, always adsorbed in the positions on top of the surface Ga atoms (On-top). Ammonia adsorption at GaN(0001) surface proceeds molecularly to ammonia in the On-top position or dissociatively into NH2 radicals in bridge (NH2-bridge) or On-top positions or into NH radicals in H3 (NH-H3) site. Presence of these species affects Fermi level pinning at the surface due to creation of new surface states. The Fermi level pinning in function of the surface attached species concentration was determined using extended electron counting rule (EECR). Results of ab initio calculations fully proved validity of the EECR predictions. Thermodynamic analysis of the surface in equilibrium with molecular hydrogen and ammonia vapor mixture is made giving the range of ammonia and hydrogen pressures, corresponding to Fermi level pinned at Ga-broken bond state for NH-H3&H and NH3&H and NH2-bridge&H coverage and at VBM for NH3 & H coverage. As the region of Fermi level pinned at Ga broken bond state corresponds to very low pressures, at pressures close to normal, GaN(0001) surface is almost totally covered by H, NH3 and NH2 located in On-top positions. It is also shown however that dominant portion of the hydrogen and ammonia pressures corresponds to Fermi level not pinned. Among them are these corresponding to MOVPE and HVPE growth conditions in which the surface is almost fully covered by NH3, NH2 and H species in On-top positions.

  7. Handel med fast ejendom

    DEFF Research Database (Denmark)

    Edlund, Hans Henrik

    Bogen tilstræber at give et overblik over nogle af de vigtigste generelle problemområder på markedet for ejendomshandel, der jo bliver mere og mere kompliceret. Værket er opdelt i følgende hovedafsnit: Ejendomsbegrebet. Indgåelse af aftale om salg af fast ejendom. Begrænsninger i adgangen til...

  8. Not so fast

    DEFF Research Database (Denmark)

    Marras, Stefano; Noda, Takuji; Steffensen, John Fleng

    2015-01-01

    , it is an open question whether such supposedly very fast swimmers do use high-speed bursts when feeding on evasive prey, in addition to using their bill for slashing prey. Here, we measured the swimming behavior of sailfish by using high-frequency accelerometry and high-speed video observations during predator...

  9. Fast Passenger Tracks Network

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    China’s fast passenger tracks network consists of four parts:express rail- way with speeds between 300km/h and 350 kin/h,passenger rail lines with speeds between 200 km/h and 250 km/h,intercity high-speed railways that run

  10. Integral Fast Reactor concept

    Energy Technology Data Exchange (ETDEWEB)

    Till, C.E.; Chang, Y.I.

    1986-01-01

    The Integral Fast Reactor (IFR) is an innovative LMR concept, being developed at Argonne National Laboratory, that fully exploits the inherent properties of liquid metal cooling and metallic fuel to achieve breakthroughs in economics and inherent safety. This paper describes key features and potential advantages of the IFR concept, technology development status, fuel cycle economics potential, and future development path.

  11. Fast Air Temperature Sensors

    DEFF Research Database (Denmark)

    Hendricks, Elbert

    1998-01-01

    The note documents briefly work done on a newly developed sensor for making fast temperature measurements on the air flow in the intake ports of an SI engine and in the EGR input line. The work reviewed has been carried out in close cooperation with Civ. Ing. Michael Føns, the author (IAU...

  12. Parallel Fast Legendre Transform

    NARCIS (Netherlands)

    Alves de Inda, M.; Bisseling, R.H.; Maslen, D.K.

    2001-01-01

    We discuss a parallel implementation of a fast algorithm for the discrete polynomial Legendre transform We give an introduction to the DriscollHealy algorithm using polynomial arithmetic and present experimental results on the eciency and accuracy of our implementation The algorithms were implemente

  13. Foinaven fast track flowlines

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, L.H.; Mair, J.

    1996-12-31

    The decision by British Petroleum to develop offshore fields west of the Shetlands in water depths exceeding 500 meters within three and a half years of discovery posed a unique submarine pipeline installation challenge. This paper summarizes the salient features of a fast track program to install a diverless subsea pipeline system using rigid reeled pipe technology in an offshore frontier area.

  14. Fast food tips

    Science.gov (United States)

    ... Order smaller servings when you can. Split some fast-food items to reduce calories and fat. Ask for a "doggy bag." You can also leave the extra food on your plate. Your food choices can teach your children how to eat healthy, too. Choosing a variety ...

  15. Fast Fourier Orthogonalization

    NARCIS (Netherlands)

    Ducas, L.; Prest, T.; Abramov, S.A.; Zima, E.V.; Gao, X-S.

    2016-01-01

    The classical fast Fourier transform (FFT) allows to compute in quasi-linear time the product of two polynomials, in the {\\em circular convolution ring} R[x]/(x^d−1) --- a task that naively requires quadratic time. Equivalently, it allows to accelerate matrix-vector products when the matrix is *circ

  16. Tachycardia | Fast Heart Rate

    Science.gov (United States)

    ... SA) node --- the heart's natural pacemaker - sends out electrical signals faster than usual. The heart rate is fast, but the heart beats properly. Causes of sinus tachycardia A rapid heartbeat may be your body's response to common conditions such as: Fever Anxiety ...

  17. Linearly polarized single photon antibunching from a site-controlled InGaN quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Jemsson, Tomas; Machhadani, Houssaine; Karlsson, K. Fredrik; Hsu, Chih-Wei; Holtz, Per-Olof [Department of Physics, Chemistry, and Biology (IFM), Semiconductor Materials, Linköping University, S-58183 Linköping (Sweden)

    2014-08-25

    We report on the observation of linearly polarized single photon antibunching in the excitonic emission from a site-controlled InGaN quantum dot. The measured second order coherence function exhibits a significant dip at zero time difference, corresponding to g{sub m}{sup 2}(0)=0.90 under continuous laser excitation. This relatively high value of g{sub m}{sup 2}(0) is well understood by a model as the combination of short exciton life time (320 ps), limited experimental timing resolution and the presence of an uncorrelated broadband background emission from the sample. Our result provides the first rigorous evidence of InGaN quantum dot formation on hexagonal GaN pyramids, and it highlights a great potential in these dots as fast polarized single photon emitters if the background emission can be eliminated.

  18. Modeling and optimization of a double-well double-barrier GaN/AlGaN/GaN/AlGaN resonant tunneling diode

    Science.gov (United States)

    Liu, Yang; Gao, Bo; Gong, Min; Shi, Ruiying

    2017-06-01

    The influence of a GaN layer as a sub-quantum well for an AlGaN/GaN/AlGaN double barrier resonant tunneling diode (RTD) on device performance has been investigated by means of numerical simulation. The introduction of the GaN layer as the sub-quantum well turns the dominant transport mechanism of RTD from the 3D-2D model to the 2D-2D model and increases the energy difference between tunneling energy levels. It can also lower the effective height of the emitter barrier. Consequently, the peak current and peak-to-valley current difference of RTD have been increased. The optimal GaN sub-quantum well parameters are found through analyzing the electrical performance, energy band, and transmission coefficient of RTD with different widths and depths of the GaN sub-quantum well. The most pronounced electrical parameters, a peak current density of 5800 KA/cm2, a peak-to-valley current difference of 1.466 A, and a peak-to-valley current ratio of 6.35, could be achieved by designing RTD with the active region structure of GaN/Al0.2Ga0.8 N/GaN/Al0.2Ga0.8 N (3 nm/1.5 nm/1.5 nm/1.5 nm).

  19. Bio-oil production from palm fronds by fast pyrolysis process in fluidized bed reactor

    Science.gov (United States)

    Rinaldi, Nino; Simanungkalit, Sabar P.; Kiky Corneliasari, S.

    2017-01-01

    Fast pyrolysis process of palm fronds has been conducted in the fluidized bed reactor to yield bio-oil product (pyrolysis oil). The process employed sea sand as the heat transfer medium. The objective of this study is to design of the fluidized bed rector, to conduct fast pyrolysis process to product bio-oil from palm fronds, and to characterize the feed and bio-oil product. The fast pyrolysis process was conducted continuously with the feeding rate around 500 g/hr. It was found that the biomass conversion is about 35.5% to yield bio-oil, however this conversion is still minor. It is suggested due to the heating system inside the reactor was not enough to decompose the palm fronds as a feedstock. Moreover, the acids compounds ware mostly observed on the bio-oil product.

  20. Surface chemistry of new As precursors for MOVPE and MOMBE: phenylarsine and tertiarybutylarsine on GaAs(100)

    Science.gov (United States)

    Kaul, P.; Schütze, A.; Kohl, D.; Brauers, A.; Weyers, M.

    1992-10-01

    Surface reactions of PhAs and tBAs on unoxidized and thermally oxidized GaAs(100) were studied in an UHV chamber using a differentially pumped quadrupole mass spectrometer and a molecular beam nozzle. A special sample holder allowed periodic switching between an unoxidized and an oxidized surface to observe small differences in reactivity. The following assumptions are compatible with the experimental results: Adsorption of PhAs or tBAs on GaAs(100) followed by rupture of the As-H bonds is the first step. Most of the organometallic radicals desorb from the surface, a fraction decomposes further by rupture of the As-C bond. The organic radicals react with the surface hydrogen and desorb as benzene and butane or butene, respectively. Low values of the activation energies ( ≤ 0.4 eV) for the different reaction steps suggest a diffusion of PhAs or tBAs on the surface as the rate limiting step for the overall reaction. A comparison of oxidized and unoxidized surfaces exposed to a constant gas flux of PhAs or tBAs revealed a reduced reactivity on the oxidized surface. Thermodesorption experiments with oxidized GaAs(100) surfaces showed that the desorption temperature of GA 2O decreased from 862 K without tBAs to 835 K in a tBAs flux. During this annealing process a reaction between the surface oxide and organic radicals from the tBAs decomposition seems to form a highly stable contamination layer which was observed by X-ray photoelectron spectroscopy. This contamination of the surface can be avoided by annealing in UHV without any As-species present and monitoring the Ga 2O flux from the surface with a mass spectrometer because non-stoichiometric evaporation of GaAs occurs only after desorption of the oxide.

  1. Simulation of polarization effects in AlGaN/GaN heterojunction

    Institute of Scientific and Technical Information of China (English)

    LI; Na; ZHAO; Degang; YANG; Hui

    2004-01-01

    A method for introducing polarization effects in the simulation of GaN-based heterojunction devices is proposed. A δ doping layer is inserted at the interface of heterojunction and the ionized donors or acceptors act as polarization induced fixed charges. Thus polarization effects can be taken into account in a traditional device simulator. Ga-face and N-face single AlGaN/GaN heterostructures are simulated, and the simulation results show that carrier confinement takes place only in the former structure while not in the latter one. The sheet density of free electrons at the interface of Ga-face AlGaN/GaN increases with the Al composition and the thickness of AlGaN. The consistence of simulation results with the experiments and calculations reported elsewhere shows that this method can effectively introduce polarization effects in the simulation of GaN-based heterojunction devices.

  2. Gate Leakage Current Reduction With Advancement of Graded Barrier AlGaN/GaN HEMT

    Directory of Open Access Journals (Sweden)

    Palash Das

    2011-01-01

    Full Text Available The gate leakage current reduction solution of AlGaN/GaN HEMT device issue has been addressed in this paper with compositional grading of AlGaN barrier layer. This work is also conjugated with the critical thickness limitation of heterostructure material growth. Hence, critical thickness calculation of AlGaN over GaN has been kept in special view. 1D Schrodinger and Poisson solver was used to calculate the 2DEG concentration and effective location to use it in the ATLAS device simulator for the predictions. The proposed Al0.50Ga0.50N/Al0.35Ga0.65N/Al0.20Ga0.80N/GaN HEMT structure exhibits the leakage current of the order of around 15 nA/mm at gate voltage of 1 V.

  3. Titanium induced polarity inversion in ordered (In,Ga)N/GaN nanocolumns

    Science.gov (United States)

    Kong, X.; Li, H.; Albert, S.; Bengoechea-Encabo, A.; Sanchez-Garcia, M. A.; Calleja, E.; Draxl, C.; Trampert, A.

    2016-02-01

    We report on the formation of polarity inversion in ordered (In,Ga)N/GaN nanocolumns grown on a Ti-masked GaN-buffered sapphire substrate by plasma assisted molecular beam epitaxy. High-resolution transmission electron microscopy and electron energy-loss spectroscopy reveal a stacking fault-like planar defect at the homoepitaxial GaN interface due to Ti incorporation, triggering the generation of N-polar domains in Ga-polar nanocolumns. Density functional theory calculations are applied to clarify the atomic configurations of a Ti monolayer occupation on the GaN (0002) plane and to prove the inversion effect. The polarity inversion leads to an enhanced indium incorporation in the subsequent (In,Ga)N segment of the nanocolumn. This study provides a deeper understanding of the effects of Ti mask in the well-controlled selective area growth of (In,Ga)N/GaN nanocolumns.

  4. Effect of substrate offcut on AlGaN/GaN HFET structures on bulk GaN substrates

    Science.gov (United States)

    Leach, J. H.; Biswas, N.; Paskova, T.; Preble, E. A.; Evans, K. R.; Wu, M.; Ni, X.; Li, X.; Özgür, Ü.; Morkoç, H.

    2011-02-01

    Bulk GaN substrates promise to bring the full potential of nitride-based devices to bear since they offer a low thermal and lattice mismatched alternative to foreign substrates for epitaxial growth. However, due to the high cost and low availability of bulk GaN substrates, effects such as surface misorientation (offcut), surface polishing, and preparation of such substrates on subsequent epitaxy are still not well understood. As such, AlGaN/GaN heterostructures with nominal Al compositions of 25% were grown by MOCVD on semi-insulating bulk GaN substrates with offcuts ranging from 0.05 to 1.95° in the m-direction (10 10) to attempt to determine the optimal offcut for bulk GaN substrates for AlGaN-based HFET devices. X-ray diffraction (XRD) studies indicate that the Al composition does not vary with offcut, however reciprocal space mapping shows evidence of strain relaxation of the AlGaN in samples grown on substrates with offcut >1.1°. Additionally, we observed a minimum in sheet resistance of the 2DEGs for substrates with offcuts near 0.5°, arising from higher mobilities in these samples. Evidence of an optimal substrate misorientation is important for AlGaN-based devices grown on bulk GaN substrates.

  5. AlGaN/GaN high electron mobility transistors with selective area grown p-GaN gates

    Science.gov (United States)

    Yuliang, Huang; Lian, Zhang; Zhe, Cheng; Yun, Zhang; Yujie, Ai; Yongbing, Zhao; Hongxi, Lu; Junxi, Wang; Jinmin, Li

    2016-11-01

    We report a selective area growth (SAG) method to define the p-GaN gate of AlGaN/GaN high electron mobility transistors (HEMTs) by metal-organic chemical vapor deposition. Compared with Schottky gate HEMTs, the SAG p-GaN gate HEMTs show more positive threshold voltage (V th) and better gate control ability. The influence of Cp2Mg flux of SAG p-GaN gate on the AlGaN/GaN HEMTs has also been studied. With the increasing Cp2Mg from 0.16 μmol/min to 0.20 μmol/min, the V th raises from -0.67 V to -0.37 V. The maximum transconductance of the SAG HEMT at a drain voltage of 10 V is 113.9 mS/mm while that value of the Schottky HEMT is 51.6 mS/mm. The SAG method paves a promising way for achieving p-GaN gate normally-off AlGaN/GaN HEMTs without dry etching damage. Project supported by the National Natural Sciences Foundation of China (Nos. 61376090, 61306008) and the National High Technology Program of China (No. 2014AA032606).

  6. Simulating propagation of decomposed elastic waves using low-rank approximate mixed-domain integral operators for heterogeneous transversely isotropic media

    KAUST Repository

    Cheng, Jiubing

    2014-08-05

    In elastic imaging, the extrapolated vector fields are decomposed into pure wave modes, such that the imaging condition produces interpretable images, which characterize reflectivity of different reflection types. Conventionally, wavefield decomposition in anisotropic media is costly as the operators involved is dependent on the velocity, and thus not stationary. In this abstract, we propose an efficient approach to directly extrapolate the decomposed elastic waves using lowrank approximate mixed space/wavenumber domain integral operators for heterogeneous transverse isotropic (TI) media. The low-rank approximation is, thus, applied to the pseudospectral extrapolation and decomposition at the same time. The pseudo-spectral implementation also allows for relatively large time steps in which the low-rank approximation is applied. Synthetic examples show that it can yield dispersionfree extrapolation of the decomposed quasi-P (qP) and quasi- SV (qSV) modes, which can be used for imaging, as well as the total elastic wavefields.

  7. High gain GaAs photoconductive semiconductor switches for ground penetrating radar

    Energy Technology Data Exchange (ETDEWEB)

    Loubriel, G.M.; Aurand, J.F.; Buttram, M.T.; Zutavern, F.J.; Helgeson, W.D.; O`Malley, M.W. [Sandia National Labs., Albuquerque, NM (United States); Brown, D.J. [Ktech Corp., Albuquerque, NM (United States)

    1996-07-01

    The ability of high gain GaAs Photoconductive Semiconductor switches (PCSS) to deliver high peak power, fast risetime pulses when triggered with small laser diode arrays makes them suitable for their use in radars that rely on fast impulses. This type of direct time domain radar is uniquely suited for observation of large structures under ground because it can operate at low frequencies and at high average power. This paper will summarize the state-of-the-art in high gain GaAs switches and discuss their use in a radar transmitter. We will also present a summary of an analysis of the effectiveness of different pulser geometries that result in transmitted pulses with varying frequency content. To this end we developed a simple model that includes transmit and receive antenna response, attenuation and dispersion of the electromagnetic impulses by the soil, and target cross sections.

  8. Radar Waveform Pulse Analysis Measurement System for High-Power GaN Amplifiers

    Science.gov (United States)

    Thrivikraman, Tushar; Perkovic-Martin, Dragana; Jenabi, Masud; Hoffman, James

    2012-01-01

    This work presents a measurement system to characterize the pulsed response of high-power GaN amplifiers for use in space-based SAR platforms that require very strict amplitude and phase stability. The measurement system is able to record and analyze data on three different time scales: fast, slow, and long, which allows for greater detail of the mechanisms that impact amplitude and phase stability. The system is fully automated through MATLAB, which offers both instrument control capability and in-situ data processing. To validate this system, a high-power GaN HEMT amplifier operated in saturation was characterized. The fast time results show that variations to the amplitude and phase are correlated to DC supply transients, while long time characteristics are correlated to temperature changes.

  9. Ultraviolet Phototransistors on AlGaN/GaN Heterostructures

    Institute of Scientific and Technical Information of China (English)

    CHEN Chen; JIANG Wen-Hai; REN Chun-Jiang; LI Zhong-Hui; JIAO Gang; DONG Xun; CHEN Tang-Sheng

    2007-01-01

    We report on the fabrication and characterization of phototransistors based on AlGaN/GaN heterostructure grown over 6H-SiC substrates. The device has two functions: as a high electron mobility transistor (HEMT) and an ultraviolet photodetector at the same time. As an HEMT, its maximum transconductance is 170 mS/mm, while the minimum cutoff frequency fT and the maximum oscillation frequency fm axe 19 and 35 GHz, respectively.As a photodetector, the device is visible blind, with an ultraviolet/green contrast of three orders of magnitude,and a responsivity as high as 1700 A/W at the wavelength of 362nm.

  10. InGaN/GaN Nanowire LEDs and Lasers

    KAUST Repository

    Zhao, Chao

    2016-01-01

    The large specific surface, and the associated high density of surface states was found to limit the light output power and quantum efficiency of nanowire-array devices, despite their potential for addressing the “green-gap” and efficiency-droop issues. The phonon and carrier confinement in nanowires also led to junction heating, and reduced heat dissipation. In this paper, we will present our studies on effective surface states passivation in InGaN/GaN quantum-disks (Qdisks)-in-nanowire light-emitting diodes (LEDs) and lasers grown on silicon (Si), as well as our recent work on nanowires LEDs grown on bulk-metal, a non-conventional substrate.

  11. GaAs wafer overlay performance affected by annealing heat treatment: II

    Science.gov (United States)

    Liu, Ying; Black, Iain

    2002-07-01

    Further analysis on how wafer distortion affecting the overlay performance during annealing treatment in GaAs wafer fabrication was conducted quantitatively using MONO-LITH software. The experimental results were decomposed as wafer translation, scaling at X and Y direction, rotation and orthogonality. The grid residual was used to describe non- correctable distortion of the wafers, which fits the equations given below: Residual equals Measured - Modeled, which is not a modeled component. The Vector Map displays distribution of error vectors over the wafer or field for various components or overall effect. Based on the component analysis that the misalignment caused by translation and scaling can be compensated by heat treatment if the wafer is placed at a favorable orientation. This can help mitigate the effects of substrate quality in manufactory.

  12. 酿造细菌分解纤维素的初步研究%Cellulose decomposing capability of bacteria isolated from Luzhou-flavor liquor brewing environment

    Institute of Scientific and Technical Information of China (English)

    王怡; 何奉芹; 罗琳; 李龙彬; 游玲

    2011-01-01

    To detect the cellulose decomposing capability of bacteria isolated from Luzhou-flavor liquor brewing environment in Yibin region and explore grain cellulose decomposing caused by these bacteria, cellulose decomposing capability of 530 strains isolated from Luzhou-flavor liquor brewing environment in Yibin region were detected by plating method. The results showed that bacteria isolated from the koji room and fermentative grains had higher cellulose decomposing capability among all strains. The cellulose decomposing capability of Bacillus cereus, Bacillus methy-lotrophicus, Bacillus aryabhattai, Bacillus tequilensis, Bacillus thuringiensis were higher than other strains. The results indicated that the cellulose decomposing capability of bacteria were closely related to sources and species.%为了解宜宾浓香型白酒酿造环境中分离到的细菌对纤维素的分解能力,进而探讨其在固态发酵过程中对谷物纤维的分解情况,采用平板培养法,对分离自宜宾浓香型白酒产区的530株细菌分解纤维素的能力测试.结果表明分离自曲房、糟醅中的细菌可分解纤维素菌所占比例较高;Bacillus cereus、Bacillus methylotrophicus、Bacillus aryabhattai、Bacillus tequilensis、Bacillus thuringiensis5个种属的细菌分解纤维素能力较其他强.研究表明酿造细菌分解纤维素能力与来源和种属有密切的关系.

  13. Medium energy proton radiation damage to (AlGa)As-GaAs solar cells

    Science.gov (United States)

    Loo, R. Y.; Kamath, G. S.; Knechtli, R. C.

    1982-01-01

    The performance of (AlGa)As-GaAs solar cells irradiated by medium energy 2, 5, and 10 MeV protons was evaluated. The Si cells without coverglass and a number of GaAs solar cells with 12 mil coverglass were irradiated simultaneously with bare GaAs cells. The cell degradation is directly related to the penetration of depth of protons with GaAs. The influence of periodic and continuous thermal annealing on the GaAs solar cells was investigated.

  14. SEMICONDUCTOR DEVICES: AlGaN/GaN double-channel HEMT

    Science.gov (United States)

    Si, Quan; Yue, Hao; Xiaohua, Ma; Pengtian, Zheng; Yuanbin, Xie

    2010-04-01

    The fabrication of AlGaN/GaN double-channel high electron mobility transistors on sapphire substrates is reported. Two carrier channels are formed in an AlGaN/GaN/AlGaN/GaN multilayer structure. The DC performance of the resulting double-channel HEMT shows a wider high transconductance region compared with single-channel HEMT. Simulations provide an explanation for the influence of the double-channel on the high transconductance region. The buffer trap is suggested to be related to the wide region of high transconductance. The RF characteristics are also studied.

  15. Blue light emission from the heterostructured ZnO/InGaN/GaN

    OpenAIRE

    Wang, Ti; WU Hao; Wang, Zheng; Chen, Chao; Liu, Chang

    2013-01-01

    ZnO/InGaN/GaN heterostructured light-emitting diodes (LEDs) were fabricated by molecular beam epitaxy and atomic layer deposition. InGaN films consisted of an Mg-doped InGaN layer, an undoped InGaN layer, and a Si-doped InGaN layer. Current-voltage characteristic of the heterojunction indicated a diode-like rectification behavior. The electroluminescence spectra under forward biases presented a blue emission accompanied by a broad peak centered at 600 nm. With appropriate emission intensity r...

  16. Brittle-Ductile Relaxation Kinetics of Strained AlGaN/GaN

    Energy Technology Data Exchange (ETDEWEB)

    CHASON, E.; FLORO, JERROLD A.; FOLLSTAEDT, DAVID M.; HAN, JUNG; HEARNE, SEAN JOSEPH; LEE, STEPHEN R.; TSONG, I.S.T.

    1999-10-05

    The authors have directly measured the stress evolution during metal organic chemical vapor deposition of AlGaN/GaN heterostructures on sapphire. In situ stress measurements were correlated with ex situ microstructural analysis to directly determine a critical thickness for cracking and the subsequent relaxation kinetics of tensile-strained Al{sub x}Ga{sub 1{minus}x}N on GaN. Cracks appear to initiate the formation of misfit dislocations at the AlGaN/GaN interface, which account for the majority of the strain relaxation.

  17. Contactless Mobility, Carrier Density, and Sheet Resistance Measurements on Si, GaN, and AlGaN/GaN High Electron Mobility Transistor (HEMT) Wafers

    Science.gov (United States)

    2015-02-01

    Si, GaN, and AlGaN/GaN High Electron Mobility Transistor (HEMT) Wafers by Randy P Tompkins and Danh Nguyen Approved for...High Electron Mobility Transistor (HEMT) Wafers by Randy P. Tompkins Sensors and Electron Devices Directorate Danh Nguyen Lehighton...Resistance Measurements on Si, GaN, and AlGaN/GaN High Electron Mobility Transistor (HEMT) Wafers 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM

  18. Engineering of electric field distribution in GaN(cap)/AlGaN/GaN heterostructures: theoretical and experimental studies

    Science.gov (United States)

    Gladysiewicz, M.; Janicki, L.; Misiewicz, J.; Sobanska, M.; Klosek, K.; Zytkiewicz, Z. R.; Kudrawiec, R.

    2016-09-01

    Polarization engineering of GaN-based heterostructures opens a way to develop advanced transistor heterostructures, although measurement of the electric field in such heterostructures is not a simple task. In this work, contactless electroreflectance (CER) spectroscopy has been applied to measure the electric field in GaN-based heterostructures. For a set of GaN(d  =  0, 5, 15, and 30 nm)/AlGaN(20 nm)/GaN(buffer) heterostructures a decrease of electric field in the GaN(cap) layer from 0.66 MV cm-1 to 0.27 MV cm-1 and an increase of the electric field in the AlGaN layer from 0.57 MV cm-1 to 0.99 MV cm-1 have been observed with the increase in the GaN(cap) thickness from 5-30 nm. For a set of GaN(20 nm)/AlGaN(d  =  10, 20, 30, and 40 nm)/GaN(buffer) heterostructures a decrease of the electric field in the AlGaN layer from 1.77 MV cm-1 to 0.64 MV cm-1 and an increase of the electric field in the GaN layer from 0.57 MV cm-1 to 0.99 MV cm-1 were observed with the increase in the AlGaN thickness from 10-40 nm. To determine the distribution of the electric field in these heterostructures the Schrödinger and Poisson equations are solved in a self-consistent manner and matched with experimental data. It is shown that the built-in electric field in the GaN(cap) and AlGaN layers obtained from measurements does not reach values of electric field resulting only from polarization effects. The measured electric fields are smaller due to a screening of polarization effects by free carriers, which are inhomogeneously distributed across the heterostructure and accumulate at interfaces. The results clearly demonstrate that CER measurements supported by theoretical calculations are able to determine the electric field distribution in GaN-based heterostructures quantitatively, which is very important for polarization engineering in this material system.

  19. First-principles study of SF{sub 6} decomposed gas adsorbed on Au-decorated graphene

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoxing, E-mail: xiaoxing.zhang@outlook.com [State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Chongqing 400044 (China); Yu, Lei; Gui, Yingang [State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Chongqing 400044 (China); Hu, Weihua [Institute for Clean Energy & Advanced Materials, Southwest University, Chongqing 400715 (China)

    2016-03-30

    Graphical abstract: - Highlights: • We theoretically investigated the decomposed gaseous components of sulfur hexafluoride (SF{sub 6}), namely, H{sub 2}S, SO{sub 2}, SOF{sub 2}, and SO{sub 2}F{sub 2}, adsorbed on pristine and Au-embedded graphene based on DFT-D, in which the van der Waals effect is considered. • H{sub 2}S, SO{sub 2}, SOF{sub 2}, and SO{sub 2}F{sub 2} are chemisorption on Au-doped graphene, appreciably stronger than physisorption on pristine graphene in which the van der Waals dominates. • Only H{sub 2}S exhibits n-type doping to Au-graphene, whereas the rest gases exhibit p-type doping. The n-type and p-type sensing behaviors that Au-doped graphene displays to different gases play a crucial role in selective sensing application. • Magnetic moments fluctuate substantially in the original Au-graphene when H{sub 2}S and SO{sub 2} are adsorbed. While the adsorption effects of SOF{sub 2} and SO{sub 2}F{sub 2} generate magnetism quenching. The different changes of magnetic moments in every adsorption system provide another approach to selective detection. • The charge transfer mechanism is deeply discussed in this paper. - Abstract: We theoretically investigated the decomposed gaseous components of sulfur hexafluoride (SF{sub 6}), namely, H{sub 2}S, SO{sub 2}, SOF{sub 2}, and SO{sub 2}F{sub 2}, adsorbed on pristine and Au-embedded graphene based on the revised Perdew–Burke–Ernzerhof calculation, which empirically includes a dispersion correction (DFT-D) for van der Waals interaction with standard generalized gradient approximation. Pristine graphene exhibits weak adsorption and absence of charge transfer, which indicates barely satisfactory sensing for decomposed components. The Au atom introduces magnetism to the pristine graphene after metal-embedded decoration as well as enhances conductivity. All four molecules induce certain hybridization between the molecules and Au-graphene, which results in chemical interactions. SOF{sub 2} and SO

  20. Beyond Fast Mapping

    OpenAIRE

    Carey, Susan

    2010-01-01

    Since the seminal 1957 studies of word learning by Roger Brown, most experimental studies of lexical acquisition have concerned fast mapping: the process through which a new lexical entry is established, and through which representations of the linguistic context of a newly heard word interact with representations of its nonlinguistic context to fix an initial partial meaning. Here I focus on the subsequent extended process through which the adult meaning is approximated. Two factors lead to ...

  1. Fast Radio Bursts

    Indian Academy of Sciences (India)

    Akshaya Rane; Duncan Lorimer

    2017-09-01

    We summarize our current state of knowledge of fast radio bursts (FRBs) which were first discovered a decade ago. Following an introduction to radio transients in general, including pulsars and rotating radio transients, we discuss the discovery of FRBs. We then discuss FRB follow-up observations in the context of repeat bursts before moving on to review propagation effects on FRB signals, FRB progenitor models and an outlook on FRBs as potential cosmological tools.

  2. PHENIX Fast TOF

    Energy Technology Data Exchange (ETDEWEB)

    Soha, Aria [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Chiu, Mickey [Brookhaven National Lab. (BNL), Upton, NY (United States); Mannel, Eric [Brookhaven National Lab. (BNL), Upton, NY (United States); Stoll, Sean [Brookhaven National Lab. (BNL), Upton, NY (United States); Lynch, Don [Brookhaven National Lab. (BNL), Upton, NY (United States); Boose, Steve [Brookhaven National Lab. (BNL), Upton, NY (United States); Northacker, Dave [Brookhaven National Lab. (BNL), Upton, NY (United States); Alfred, Marcus [Howard Univ., Washington, DC (United States); Lindesay, James [Howard Univ., Washington, DC (United States); Chujo, Tatsuya [Univ. of Tsukuba (Japan); Inaba, Motoi [Univ. of Tsukuba (Japan); Nonaka, Toshihiro [Univ. of Tsukuba (Japan); Sato, Wataru [Univ. of Tsukuba (Japan); Sakatani, Ikumi [Univ. of Tsukuba (Japan); Hirano, Masahiro [Univ. of Tsukuba (Japan); Choi, Ihnjea [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2014-01-15

    This is a technical scope of work (TSW) between the Fermi National Accelerator Laboratory (Fermilab) and the experimenters of PHENIX Fast TOF group who have committed to participate in beam tests to be carried out during the FY2014 Fermilab Test Beam Facility program. The goals for this test beam experiment are to verify the timing performance of the two types of time-of-flight detector prototypes.

  3. Fast Air Temperature Sensors

    DEFF Research Database (Denmark)

    Hendricks, Elbert

    1998-01-01

    The note documents briefly work done on a newly developed sensor for making fast temperature measurements on the air flow in the intake ports of an SI engine and in the EGR input line. The work reviewed has been carried out in close cooperation with Civ. Ing. Michael Føns, the author (IAU......) and Spencer C. Sorenson (ET). The theory which decribes in detail the overall dynamic chracteristics of the sensor was developed at IAU, DTU....

  4. Internal quantum efficiency in yellow-amber light emitting AlGaN-InGaN-GaN heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Ngo, Thi Huong; Gil, Bernard; Valvin, Pierre [Laboratoire Charles Coulomb – UMR 5221, CNRS and University Montpellier, Case courier 074, 34095 Montpellier Cedex 5 (France); Damilano, Benjamin; Lekhal, Kaddour; De Mierry, Philippe [CRHEA-CNRS Centre de Recherche sur l' Hétéro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique, rue Bernard Gregory, 06560 Valbonne (France)

    2015-09-21

    We determine the internal quantum efficiency of strain-balanced AlGaN-InGaN-GaN hetero-structures designed for yellow-amber light emission, by using a recent model based on the kinetics of the photoluminescence decay initiated by Iwata et al. [J. Appl. Phys. 117, 075701 (2015)]. Our results indicate that low temperature internal quantum efficiencies sit in the 50% range and we measure that adding an AlGaN layer increases the internal quantum efficiency from 50% up to 57% with respect to the GaN-InGaN case. More dramatic, it almost doubles from 2.5% up to 4.3% at room temperature.

  5. ADT fast losses MD

    CERN Document Server

    Priebe, A; Dehning, B; Redaelli, S; Salvachua Ferrando, BM; Sapinski, M; Solfaroli Camillocci, M; Valuch, D

    2013-01-01

    The fast beam losses in the order of 1 ms are expected to be a potential major luminosity limitation for higher beam energies after the LHC long shutdown (LS1). Therefore a Quench Test is planned in the winter 2013 to estimate the quench limit in this timescale and revise the current models. This experiment was devoted to determination the LHC Transverse Damper (ADT) as a system for fast losses induction. A non-standard operation of the ADT was used to develop the beam oscillation instead of suppressing them. The sign flip method had allowed us to create the fast losses within several LHC turns at 450 GeV during the previous test (26th March 2012). Thus, the ADT could be potentially used for the studies of the UFO ("Unidentied Falling Object") impact on the cold magnets. Verification of the system capability and investigations of the disturbed beam properties were the main objectives of this MD. During the experiment, the pilot bunches of proton beam were excited independently in the horizontal and vertical ...

  6. Fast Light Optical Gyroscopes

    Science.gov (United States)

    Smith, David D.

    2015-01-01

    Next-generation space missions are currently constrained by existing spacecraft navigation systems which are not fully autonomous. These systems suffer from accumulated dead-reckoning errors and must therefore rely on periodic corrections provided by supplementary technologies that depend on line-of-sight signals from Earth, satellites, or other celestial bodies for absolute attitude and position determination, which can be spoofed, incorrectly identified, occluded, obscured, attenuated, or insufficiently available. These dead-reckoning errors originate in the ring laser gyros themselves, which constitute inertial measurement units. Increasing the time for standalone spacecraft navigation therefore requires fundamental improvements in gyroscope technologies. One promising solution to enhance gyro sensitivity is to place an anomalous dispersion or fast light material inside the gyro cavity. The fast light essentially provides a positive feedback to the gyro response, resulting in a larger measured beat frequency for a given rotation rate as shown in figure 1. Game Changing Development has been investing in this idea through the Fast Light Optical Gyros (FLOG) project, a collaborative effort which began in FY 2013 between NASA Marshall Space Flight Center (MSFC), the U.S. Army Aviation and Missile Research, Development, and Engineering Center (AMRDEC), and Northwestern University. MSFC and AMRDEC are working on the development of a passive FLOG (PFLOG), while Northwestern is developing an active FLOG (AFLOG). The project has demonstrated new benchmarks in the state of the art for scale factor sensitivity enhancement. Recent results show cavity scale factor enhancements of approx.100 for passive cavities.

  7. High-temperature characteristics of AixGa1-xN/GaN Schottky diodes

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiaoling; Li Fei; Lv Changzhi; Xie Xuesong; Li Ying; Mohammad S N

    2009-01-01

    High-temperature characteristics of the metal/AlxGa1_xN/GaN M/S/S (M/S/S) diodes have been studied with current-voltage (I-V) and capacitance-voltage (C-V) measurements at high temperatures. Due to the presence of the piezoelectric polarization field and a quantum well at the AIxGa1_xN/GaN interface, the AIxGa1_xN/GaNdiodes show properties distinctly different from those of the AIxGa1_xN diodes. For the AIxGa1_xN/GaN diodes, an increase in temperature accompanies an increase in barrier height and a decrease in ideality factor, while the AIxGa1_xN diodes are opposite. Furthermore, at room temperature, both reverse leakage current and reverse break-down voltage are superior for the AIxGa1_xN/GaN diodes to those for the AIxGa1_xN diodes.

  8. The GCKR rs780094 polymorphism is associated with elevated fasting serum triacylglycerol, reduced fasting and OGTT-related insulinaemia, and reduced risk of type 2 diabetes

    DEFF Research Database (Denmark)

    Sparsø, T; Andersen, G; Nielsen, T

    2007-01-01

    to metabolic traits (mainly fasting hypertriacylglycerolaemia) and traits related to pancreatic beta cell function. METHODS: The polymorphism was genotyped in 16,853 Danes using Taqman allelic discrimination. Association was analysed in case-control studies and quantitative trait analyses. We also analysed...... the possible interactive effect between the GCK -30G>A polymorphism and the GCKR rs780094 variant on metabolic traits. RESULTS: The minor GCKR A-allele of rs780094 is associated with an increased level of fasting serum triacylglycerol (p = 6 x 10(-14)), impaired fasting (p = 0.001) and OGTT-related insulin...... release (p = 3 x 10(-6)), reduced homeostasis model assessment of insulin resistance (p = 0.0004), WHO-defined dyslipidaemia (p = 6 x 10(-9)) and a modestly decreased risk of type 2 diabetes (p = 0.01). Significantly increased fasting serum insulin concentrations were demonstrated when analysing the GCK...

  9. L2 speakers decompose morphologically complex verbs: fMRI evidence from priming of transparent derived verbs.

    Science.gov (United States)

    De Grauwe, Sophie; Lemhöfer, Kristin; Willems, Roel M; Schriefers, Herbert

    2014-01-01

    In this functional magnetic resonance imaging (fMRI) long-lag priming study, we investigated the processing of Dutch semantically transparent, derived prefix verbs. In such words, the meaning of the word as a whole can be deduced from the meanings of its parts, e.g., wegleggen "put aside." Many behavioral and some fMRI studies suggest that native (L1) speakers decompose transparent derived words. The brain region usually implicated in morphological decomposition is the left inferior frontal gyrus (LIFG). In non-native (L2) speakers, the processing of transparent derived words has hardly been investigated, especially in fMRI studies, and results are contradictory: some studies find more reliance on holistic (i.e., non-decompositional) processing by L2 speakers; some find no difference between L1 and L2 speakers. In this study, we wanted to find out whether Dutch transparent derived prefix verbs are decomposed or processed holistically by German L2 speakers of Dutch. Half of the derived verbs (e.g., omvallen "fall down") were preceded by their stem (e.g., vallen "fall") with a lag of 4-6 words ("primed"); the other half (e.g., inslapen "fall asleep") were not ("unprimed"). L1 and L2 speakers of Dutch made lexical decisions on these visually presented verbs. Both region of interest analyses and whole-brain analyses showed that there was a significant repetition suppression effect for primed compared to unprimed derived verbs in the LIFG. This was true both for the analyses over L2 speakers only and for the analyses over the two language groups together. The latter did not reveal any interaction with language group (L1 vs. L2) in the LIFG. Thus, L2 speakers show a clear priming effect in the LIFG, an area that has been associated with morphological decomposition. Our findings are consistent with the idea that L2 speakers engage in decomposition of transparent derived verbs rather than processing them holistically.

  10. L2 speakers decompose morphologically complex verbs: fMRI evidence from priming of transparent derived verbs

    Directory of Open Access Journals (Sweden)

    Sophie eDe Grauwe

    2014-10-01

    Full Text Available In this fMRI long-lag priming study, we investigated the processing of Dutch semantically transparent, derived prefix verbs. In such words, the meaning of the word as a whole can be deduced from the meanings of its parts, e.g. wegleggen ‘put aside’. Many behavioral and some fMRI studies suggest that native (L1 speakers decompose transparent derived words. The brain region usually implicated in morphological decomposition is the left inferior frontal gyrus (LIFG. In non-native (L2 speakers, the processing of transparent derived words has hardly been investigated, especially in fMRI studies, and results are contradictory: Some studies find more reliance on holistic (i.e. non-decompositional processing by L2 speakers; some find no difference between L1 and L2 speakers. In this study, we wanted to find out whether Dutch transparent derived prefix verbs are decomposed or processed holistically by German L2 speakers of Dutch. Half of the derived verbs (e.g. omvallen ‘fall down’ were preceded by their stem (e.g. vallen ‘fall’ with a lag of 4 to 6 words (‘primed’; the other half (e.g. inslapen ‘fall asleep’ were not (‘unprimed’. L1 and L2 speakers of Dutch made lexical decisions on these visually presented verbs. Both ROI analyses and whole-brain analyses showed that there was a significant repetition suppression effect for primed compared to unprimed derived verbs in the LIFG. This was true both for the analyses over L2 speakers only and for the analyses over the two language groups together. The latter did not reveal any interaction with language group (L1 vs. L2 in the LIFG. Thus, L2 speakers show a clear priming effect in the LIFG, an area that has been associated with morphological decomposition. Our findings are consistent with the idea that L2 speakers engage in decomposition of transparent derived verbs rather than processing them holistically.

  11. Synthetic iron (hydr)oxide-glucose associations in subsurface soil: Effects on decomposability of mineral associated carbon.

    Science.gov (United States)

    Porras, R C; Hicks Pries, C E; Torn, M S; Nico, P S

    2017-09-13

    Soils are a globally important reservoir of organic carbon. There is a growing understanding that interactions with soil mineral phases contribute to the accumulation and retention of otherwise degradable organic matter (OM) in soils and sediments. However, the bioavailability of organic compounds in mineral-organic-associations (MOAs), especially under varying environmental conditions is not well known. To assess the impact of mineral association and warming on the decomposition of an easily respirable organic substrate (glucose), we conducted a series of laboratory incubations at different temperatures with field-collected soils from 10 to 20cm, 50-60cm, and 80-90cm depth. We added (13)C-labeled glucose either directly to native soil or sorbed to one of two synthetic iron (hydr)oxide phases (goethite and ferrihydrite) that differ in crystallinity and affinity for sorbing glucose. We found that: (1) association with the Fe (hydr)oxide minerals reduced the decomposition rate of glucose by >99.5% relative to rate of decomposition for free glucose in soil; (2) the respiration rate per gram carbon did not differ appreciably with depth, suggesting a similar degree of decomposability for native C across depths and that under the incubation conditions total carbon availability represents the principal limitation on respiration under these conditions as opposed to reduced abundance of decomposers or moisture and oxygen limitations; (3) addition of free glucose enhanced native carbon respiration at all soil depths with the largest effect at 50-60cm; (4) in general respiration of the organo-mineral complex (glucose and iron-(hydr)oxide) was less temperature sensitive than was respiration of native carbon; (5) the addition of organic free mineral decreased the rate of soil respiration in the intermediate 50-60cm depth soil. The results emphasize the key role of MOAs in regulating the fluxes of carbon from soils to the atmosphere and in turn the stocks of soil carbon

  12. Highly efficient single-junction GaAs thin-film solar cell on flexible substrate

    Science.gov (United States)

    Moon, Sunghyun; Kim, Kangho; Kim, Youngjo; Heo, Junseok; Lee, Jaejin

    2016-07-01

    There has been much interest in developing a thin-film solar cell because it is lightweight and flexible. The GaAs thin-film solar cell is a top contender in the thin-film solar cell market in that it has a high power conversion efficiency (PCE) compared to that of other thin-film solar cells. There are two common structures for the GaAs solar cell: n (emitter)-on-p (base) and p-on-n. The former performs better due to its high collection efficiency because the electron diffusion length of the p-type base region is much longer than the hole diffusion length of the n-type base region. However, it has been limited to fabricate highly efficient n-on-p single-junction GaAs thin film solar cell on a flexible substrate due to technical obstacles. We investigated a simple and fast epitaxial lift-off (ELO) method that uses a stress originating from a Cr/Au bilayer on a 125-μm-thick flexible substrate. A metal combination of AuBe/Pt/Au is employed as a new p-type ohmic contact with which an n-on-p single-junction GaAs thin-film solar cell on flexible substrate was successfully fabricated. The PCE of the fabricated single-junction GaAs thin-film solar cells reached 22.08% under air mass 1.5 global illumination.

  13. Metabolic Effects of Intermittent Fasting.

    Science.gov (United States)

    Patterson, Ruth E; Sears, Dorothy D

    2017-08-21

    The objective of this review is to provide an overview of intermittent fasting regimens, summarize the evidence on the health benefits of intermittent fasting, and discuss physiological mechanisms by which intermittent fasting might lead to improved health outcomes. A MEDLINE search was performed using PubMed and the terms "intermittent fasting," "fasting," "time-restricted feeding," and "food timing." Modified fasting regimens appear to promote weight loss and may improve metabolic health. Several lines of evidence also support the hypothesis that eating patterns that reduce or eliminate nighttime eating and prolong nightly fasting intervals may result in sustained improvements in human health. Intermittent fasting regimens are hypothesized to influence metabolic regulation via effects on (a) circadian biology, (b) the gut microbiome, and (c) modifiable lifestyle behaviors, such as sleep. If proven to be efficacious, these eating regimens offer promising nonpharmacological approaches to improving health at the population level, with multiple public health benefits.

  14. Neighborhood fast food availability and fast food consumption.

    Science.gov (United States)

    Oexle, Nathalie; Barnes, Timothy L; Blake, Christine E; Bell, Bethany A; Liese, Angela D

    2015-09-01

    Recent nutritional and public health research has focused on how the availability of various types of food in a person's immediate area or neighborhood influences his or her food choices and eating habits. It has been theorized that people living in areas with a wealth of unhealthy fast-food options may show higher levels of fast-food consumption, a factor that often coincides with being overweight or obese. However, measuring food availability in a particular area is difficult to achieve consistently: there may be differences in the strict physical locations of food options as compared to how individuals perceive their personal food availability, and various studies may use either one or both of these measures. The aim of this study was to evaluate the association between weekly fast-food consumption and both a person's perceived availability of fast-food and an objective measure of fast-food presence - Geographic Information Systems (GIS) - within that person's neighborhood. A randomly selected population-based sample of eight counties in South Carolina was used to conduct a cross-sectional telephone survey assessing self-report fast-food consumption and perceived availability of fast food. GIS was used to determine the actual number of fast-food outlets within each participant's neighborhood. Using multinomial logistic regression analyses, we found that neither perceived availability nor GIS-based presence of fast-food was significantly associated with weekly fast-food consumption. Our findings indicate that availability might not be the dominant factor influencing fast-food consumption. We recommend using subjective availability measures and considering individual characteristics that could influence both perceived availability of fast food and its impact on fast-food consumption. If replicated, our findings suggest that interventions aimed at reducing fast-food consumption by limiting neighborhood fast-food availability might not be completely effective.

  15. Optical and magnetotransport properties of InGaAs/GaAsSb/GaAs structures doped with a magnetic impurity

    Energy Technology Data Exchange (ETDEWEB)

    Kalentyeva, I. L., E-mail: vikhrova@nifti.unn.ru; Zvonkov, B. N.; Vikhrova, O. V.; Danilov, Yu. A.; Demina, P. B.; Dorokhin, M. V.; Zdoroveyshchev, A. V. [Lobachevsky State University of Nizhny Novgorod (Russian Federation)

    2015-11-15

    InGaAs/GaAsSb/GaAs bilayer quantum-well structures containing a magnetic-impurity δ-layer (Mn) at the GaAs/InGaAs interface are experimentally studied for the first time. The structures are fabricated by metal organic chemical-vapor deposition (MOCVD) and laser deposition on substrates of conducting (n{sup +}) and semi-insulating GaAs in a single growth cycle. The InGaAs-layer thickness is varied from 1.5 to 5 nm. The significant effect of a decrease in the InGaAs quantum-well thickness on the optical and magnetotransport properties of the structures under study is detected. Nonlinear magnetic-field dependence of the Hall resistance and negative magnetoresistance at temperatures of ≤30–40 K, circular polarization of the electroluminescence in a magnetic field, opposite behaviors of the photoluminescence and electroluminescence emission intensities in the structures, and an increase in the contribution of indirect transitions with decreasing InGaAs thickness are observed. Simulation shows that these effects can be caused by the influence of the δ-layer of acceptor impurity (Mn) on the band structure and the hole concentration distribution in the bilayer quantum well.

  16. Dynamics of dust-free cavities behind fast projectiles in a dusty plasma under microgravity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Caliebe, D.; Arp, O.; Piel, A. [Institut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet, Kiel (Germany)

    2011-07-15

    The penetration of a dusty plasma by fast charged projectiles is studied under microgravity conditions. The mass and charge of the projectiles are larger than those of the target particles. A projectile generates a dust-free cavity in its wake, whose shape strongly depends on the projectile velocity. The faster the projectile the more elongated becomes the cavity while its cross-section decreases. The opening time of the cavity is found independent of the projectile velocity. For supersonic projectiles, the dynamics of the cavity can be decomposed into an initial impulse and a subsequent elastic response that can be modeled by a damped harmonic oscillator.

  17. Serum Lipid Profile: Fasting or Non-fasting?

    OpenAIRE

    Nigam, P. K.

    2010-01-01

    Serum lipid profile has now become almost a routine test. It is usually done in fasting state due to certain limitations in non-fasting serum sample. In the recent past efforts have been made to simplify blood sampling by replacing fasting lipid profile with non-fasting lipid profile. However, fasting specimen is preferred if cardiovascular risk assessment is based on total cholesterol, LDL cholesterol or non-HDL cholesterol. A lot has yet to be done in this area. Till then we have to believe...

  18. Serum Lipid Profile: Fasting or Non-fasting?

    OpenAIRE

    Nigam, P. K.

    2010-01-01

    Serum lipid profile has now become almost a routine test. It is usually done in fasting state due to certain limitations in non-fasting serum sample. In the recent past efforts have been made to simplify blood sampling by replacing fasting lipid profile with non-fasting lipid profile. However, fasting specimen is preferred if cardiovascular risk assessment is based on total cholesterol, LDL cholesterol or non-HDL cholesterol. A lot has yet to be done in this area. Till then we have to believe...

  19. Role of fast ignitor in fast-shock ignition concept

    Directory of Open Access Journals (Sweden)

    S. A. Ghasemi

    2014-03-01

    Full Text Available This paper deals with the role of fast ignitor in fast-shock ignition (FSI concept. The semi-analytical model indicates that the FSI target gain is a function of fast ignitor laser wavelength. If the energy of fast ignitor driver is and the laser wavelength is less than 0.53 micron, then with a fuel mass about 2 mg the FSI has a considerable advantage over pure shock ignition and the figure of merit is better than 1.2. When the wavelength of fast ignitor becomes shorter, the approaches , and for wavelengths shorter than 0.25 micron no additional is advantage is obtained.

  20. Decomposing Nekrasov Decomposition

    CERN Document Server

    Morozov, A

    2015-01-01

    AGT relations imply that the four-point conformal block admits a decomposition into a sum over pairs of Young diagrams of essentially rational Nekrasov functions - this is immediately seen when conformal block is represented in the form of a matrix model. However, the q-deformation of the same block has a deeper decomposition - into a sum over a quadruple of Young diagrams of a product of four topological vertices. We analyze the interplay between these two decompositions, their properties and their generalization to multi-point conformal blocks. In the latter case we explain how Dotsenko-Fateev all-with-all (star) pair "interaction" is reduced to the quiver model nearest-neighbor (chain) one. We give new identities for q-Selberg averages of pairs of generalized Macdonald polynomials. We also translate the slicing invariance of refined topological strings into the language of conformal blocks and interpret it as abelianization of generalized Macdonald polynomials.

  1. Decomposing Nekrasov decomposition

    Science.gov (United States)

    Morozov, A.; Zenkevich, Y.

    2016-02-01

    AGT relations imply that the four-point conformal block admits a decomposition into a sum over pairs of Young diagrams of essentially rational Nekrasov functions — this is immediately seen when conformal block is represented in the form of a matrix model. However, the q-deformation of the same block has a deeper decomposition — into a sum over a quadruple of Young diagrams of a product of four topological vertices. We analyze the interplay between these two decompositions, their properties and their generalization to multi-point conformal blocks. In the latter case we explain how Dotsenko-Fateev all-with-all (star) pair "interaction" is reduced to the quiver model nearest-neighbor (chain) one. We give new identities for q-Selberg averages of pairs of generalized Macdonald polynomials. We also translate the slicing invariance of refined topological strings into the language of conformal blocks and interpret it as abelianization of generalized Macdonald polynomials.

  2. Decomposability for stable processes

    CERN Document Server

    Wang, Yizao; Roy, Parthanil

    2011-01-01

    We characterize all possible independent symmetric $\\alpha$-stable (S$\\alpha$S) components of a non--Gaussian S$\\alpha$S process, $0<\\alpha<2$. In particular, we characterize the independent stationary S$\\alpha$S components of a stationary S$\\alpha$S process. One simple consequence of our characterization is that all stationary components of the S$\\alpha$S moving average processes are trivial. As a main application, we show that the standard Brown--Resnick process has a moving average representation. This complements a result of Kabluchko et al. (2009), who obtained mixed moving average representations for these processes. We also develop a parallel characterization theory for max-stable processes.

  3. Contrastive topics decomposed

    Directory of Open Access Journals (Sweden)

    Michael Wagner

    2012-12-01

    Full Text Available The analysis of contrastive topics introduced in Büring 1997b and further developed in Büring 2003 relies on distinguishing two types of constituents that introduce alternatives: the sentence focus, which is marked by a FOC feature, and the contrastive topic, which is marked by a CT feature. A non-compositional rule of interpretation that refers to these features is used to derive a topic semantic value, a nested set of sets of propositions. This paper presents evidence for a correlation between the restrictive syntax of nested focus operators and the syntax of contrastive topics, a correlation which is unexpected under this analysis. A compositional analysis is proposed that only makes use of the flatter focus semantic values introduced by focus operators. The analysis aims at integrating insights from the original analysis while at the same time capturing the observed syntactic restrictions. http://dx.doi.org/10.3765/sp.5.8 BibTeX info

  4. Time-resolved characterization of InAs/InGaAs quantum dot gain material for 1.3 µm lasers on gallium arsenide

    DEFF Research Database (Denmark)

    Fiore, Andrea; Borri, Paola; Langbein, Wolfgang

    2000-01-01

    The time-resolved optical characterization of InAs/InGaAs quantum dots emitting at 1.3 ìm is presented. A photoluminescence decay time of 1.8 ns and a fast rise time of 10ps are measured close to room temperature.......The time-resolved optical characterization of InAs/InGaAs quantum dots emitting at 1.3 ìm is presented. A photoluminescence decay time of 1.8 ns and a fast rise time of 10ps are measured close to room temperature....

  5. A novel oxidation-based wet etching method for AlGaN/GaN heterostructures

    Institute of Scientific and Technical Information of China (English)

    Cai Jinbao; Wang Jinyan; Liu Yang; Xu Zhe; Wang Maojun; Yu Min; Xie Bing

    2013-01-01

    A novel wet etching method for AlGaN/GaN heterojunction structures is proposed using thermal oxidation followed by wet etching in KOH solution.It is found that an AlGaN/GaN heterostructure after high temperature oxidation above 700 ℃ could be etched off in a homothermal (70 ℃) KOH solution while the KOH solution had no etching effects on the region of the A1GaN/GaN heterostructure protected by a SiO2 layer during the oxidation process.A groove structure with 150 nm step depth on an AlGaN/GaN heterostructure was formed after 8 h thermal oxidation at 900 ℃ followed by 30 min treatment in 70 ℃ KOH solution.As the oxidation time increases,the etching depth approaches saturation and the roughness of the etched surface becomes much better.The physical mechanism of this phenomenon is also discussed.

  6. GaAsP solar cells on GaP/Si with low threading dislocation density

    Science.gov (United States)

    Yaung, Kevin Nay; Vaisman, Michelle; Lang, Jordan; Lee, Minjoo Larry

    2016-07-01

    GaAsP on Si tandem cells represent a promising path towards achieving high efficiency while leveraging the Si solar knowledge base and low-cost infrastructure. However, dislocation densities exceeding 108 cm-2 in GaAsP cells on Si have historically hampered the efficiency of such approaches. Here, we report the achievement of low threading dislocation density values of 4.0-4.6 × 106 cm-2 in GaAsP solar cells on GaP/Si, comparable with more established metamorphic solar cells on GaAs. Our GaAsP solar cells on GaP/Si exhibit high open-circuit voltage and quantum efficiency, allowing them to significantly surpass the power conversion efficiency of previous devices. The results in this work show a realistic path towards dual-junction GaAsP on Si cells with efficiencies exceeding 30%.

  7. GaN Bulk Growth and Epitaxy from Ca-Ga-N Solutions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR proposal addresses the liquid phase epitaxy (LPE) of gallium nitride (GaN) films using nitrogen-enriched metal solutions. Growth of GaN from solutions...

  8. Hispanics in Fast Food Jobs.

    Science.gov (United States)

    Charner, Ivan; Fraser, Bryna Shore

    A study examined the employment of Hispanics in the fast-food industry. Data were obtained from a national survey of employees at 279 fast-food restaurants from seven companies in which 194 (4.2 percent) of the 4,660 respondents reported being Hispanic. Compared with the total sample, Hispanic fast-food employees were slightly less likely to be…

  9. InGaAs quantum well-dots based GaAs subcell with enhanced photocurrent for multijunction GaInP/GaAs/Ge solar cells

    Science.gov (United States)

    Mintairov, S. A.; Kalyuzhnyy, N. A.; Maximov, M. V.; Nadtochiy, A. M.; Zhukov, A. E.

    2017-01-01

    MOCVD-grown GaAs single-junction solar cells (SC) with quantum well-dots (QWD) were fabricated and tested. The QWD were formed by the deposition of In0.4Ga0.6As layers separated with GaAs spacers. A remarkable improvement of photocurrent was achieved and the reduction of open-circuit voltage was partly suppressed by decreasing the spacers’ growth rate as well as increasing their thickness up to 40 nm. Based on the experimentally obtained characteristics of these single-junction SCs we estimated that using QWD media in the middle (GaAs-based) subcell can provide 1 abs. %, increasing the efficiency of the triple-junction GaInP/GaAs/Ge SCs.

  10. AlGaN nanocolumns and AlGaN/GaN/AlGaN nanostructures grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Ristic, J.; Sanchez-Garcia, M.A.; Ulloa, J.M.; Calleja, E. [Departamento de Ingenieria Electronica, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria, 28040 Madrid (Spain); Sanchez-Paramo, J.; Calleja, J.M. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Jahn, U.; Trampert, A.; Ploog, K.H. [Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)

    2002-12-01

    This work reports on the characterization of hexagonal, single crystal AlGaN nanocolumns with diameters in the range of 30 to 100 nm grown by molecular beam epitaxy on Si(111) substrates. The change of the flux ratio between the Al and the total III-element controls the alloy composition. The Al composition trend versus the Al flux is consistent both with the E{sub 2} phonon energy values measured by inelastic light scattering and the luminescence emission peaks position. High quality low dimensional AlGaN/GaN/AlGaN heterostructures with five GaN quantum discs, 2 and 4 nm thick, embedded into the AlGaN columns, were designed in order to study the quantum confinement effects. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  11. Theoretical and experimental studies of electric field distribution in N-polar GaN/AlGaN/GaN heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Gladysiewicz, M., E-mail: marta.gladysiewicz@pwr.edu.pl; Janicki, L.; Kudrawiec, R. [Faculty of Fundamental Problems of Technology, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław (Poland); Siekacz, M.; Cywinski, G. [Institute of High Pressure Physics, Polish Academy of Sciences, Sokołowska 29/37, 01-142 Warsaw (Poland); Skierbiszewski, C. [Institute of High Pressure Physics, Polish Academy of Sciences, Sokołowska 29/37, 01-142 Warsaw (Poland); TopGaN Sp. z o.o., Sokołowska 29/37, 01-142 Warsaw (Poland)

    2015-12-28

    Electric field distribution in N-polar GaN(channel)/AlGaN/GaN(buffer) heterostructures was studied theoretically by solving Schrodinger and Poisson equations in a self-consistent manner for various boundary conditions and comparing results of these calculations with experimental data, i.e., measurements of electric field in GaN(channel) and AlGaN layers by electromodulation spectroscopy. A very good agreement between theoretical calculations and experimental data has been found for the Fermi-level located at ∼0.3 eV below the conduction band at N-polar GaN surface. With this surface boundary condition, the electric field distribution and two dimensional electron gas concentration are determined for GaN(channel)/AlGaN/GaN(buffer) heterostructures of various thicknesses of GaN(channel) and AlGaN layers.

  12. A thermodynamic description of metastable c-TiAlZrN coatings with triple spinodally decomposed domains

    Directory of Open Access Journals (Sweden)

    Zhou J.

    2017-01-01

    Full Text Available A critical thermodynamic assessment of the metastable c-TiAlZrN coatings, which are reported to spinodally decompose into triple domains, i.e., c-TiN, c-AlN, and c-ZrN, was performed via the CALculation of PHAse Diagram (CALPHAD technique based on the limited experimental data as well as the first-principles computed free energies. The metastable c-TiAlZrN coatings were modeled as a pseudo-ternary phase consisting of c-TiN, c-AlN and c-ZrN species, and described using the substitutional solution model. The thermodynamic descriptions for the three boundary binaries were directly taken from either the CALPHAD assessment or the first-principles results available in the literature except for a re-adjustment of the pseudo-binary c-AlN/c-ZrN system based on the experimental phase equilibria in the pseudo-ternary system. The good agreement between the calculated phase equilibria and the experimental data over the wide temperature range was obtained, validating the reliability of the presently obtained thermodynamic descriptions for the c-TiAlZrN system. Based on the present thermodynamic description, different phase diagrams and thermodynamic properties can be easily predicted. It is anticipated that the present thermodynamic description of the metastable c-TiAlZrN coatings can serve as the important input for the later quantitative description of the microstructure evolution during service life.

  13. Density-Decomposed Orbital-Free Density Functional Theory for Covalent Systems and Application to Li-Si alloys

    Science.gov (United States)

    Xia, Junchao; Carter, Emily

    2014-03-01

    We propose a density decomposition scheme using a Wang-Govind-Carter (WGC)-based kinetic energy density functional (KEDF) to accurately and efficiently simulate covalent systems within orbital-free (OF) density functional theory (DFT). By using a local, density-dependent scale function, the total density is decomposed into a localized density within covalent bond regions and a flattened delocalized density, with the former described by semilocal KEDFs and the latter treated by the WGC KEDF. The new model predicts reasonable equilibrium volumes, bulk moduli, and phase ordering energies for various semiconductors compared to Kohn-Sham (KS) DFT benchmarks. The surface energy of Si(100) also agrees well with KSDFT. We further apply the model to study mechanical properties of Li-Si alloys, which have been recently recognized as a promising candidate for next-generation anodes of Li-ion batteries with outstanding capacity. We study multiple crystalline Li-Si alloys. The WGCD KEDF predicts accurate cell lattice vectors, equilibrium volumes, elastic moduli, electron densities, alloy formation and Li adsorption energies. Because of its quasilinear scaling, coupled with the level of accuracy shown here, OFDFT appears quite promising for large-scale simulation of such materials phenomena. Office of Naval Research, National Science Foundation, Tigress High Performance Computing Center.

  14. Transfer of N and P from intact or decomposing roots of pea to barley interconnected by an arbuscular mycorrhizal fungus

    DEFF Research Database (Denmark)

    Johansen, A.; Jensen, E.S.

    1996-01-01

    The role of arbuscular mycorrhizas in the transfer of N and P between pea (Pisum sativum L.) and barley (Hordeum vulgare L.) plants was studied in a controlled environment. The plants were grown together in PVC containers, either in symbiosis with Glomus intraradices Schenck and Smith or as non......-mycorrhizal controls, and with their root systems separated by an intermediate buffer zone (2 cm), confined by fine nylon mesh. The pea donor plants were supplied simultaneously with N-15 and P-32, using a split-root labelling technique, in order to follow the flow of N and P to the barley receiver plants during 60 d...... of growth. In half of the containers, the donor-plant shoot was removed 42 d after the start of labelling and the roots were left in the soil to decompose. The reverse transfer of N and P, from barley donor to pea receiver plants was also measured to allow calculation of the net transfer through hyphae...

  15. Aquatic hyphomycete communities associated with decomposing alder leaf litter in reference headwater streams of the Basque Country (northern Spain).

    Science.gov (United States)

    Pérez, Javier; Descals, Enrique; Pozo, Jesús

    2012-08-01

    The community of aquatic hyphomycetes associated with decomposing alder leaf litter was studied during autumn-winter in nine headwater reference streams of the Basque Country (northern Spain). In order to study the spatial variability in composition and community structure, three streams from each of three different river basins were compared. The colonization dynamics and community changes throughout the decomposition process were also followed in three of the rivers (one per basin). The taxonomic richness and community structure of these fungi varied among rivers, including similar streams of a given watershed. However, neither species diversity nor total abundance was statistically related to environmental variables. Only the conidial production of two of the species, Flagellospora curvula and Lunulospora curvula appeared to be enhanced by nitrate availability in the water. The taxonomic richness and the reproductive activity (sporulation rate) were positively related to the leaf litter decomposition rate. The changes in conidial production along the process were similar for all the streams and helped explain leaf litter quality dynamics.

  16. Function of terahertz spectra in monitoring the decomposing process of biological macromolecules and in investigating the causes of photoinhibition.

    Science.gov (United States)

    Qu, Yuangang; Zhang, Shuai; Lian, Yuji; Kuang, Tingyun

    2017-03-01

    Chlorophyll a and β-carotene play an important role in harvesting light energy, which is used to drive photosynthesis in plants. In this study, terahertz (THz) and visible range spectra of chlorophyll a and β-carotene and their changes under light treatment were investigated. The results show that the all THz transmission and absorption spectra of chlorophyll a and β-carotene changed upon light treatment, with the maximum changes at 15 min of illumination indicating the greatest changes of the collective vibrational mode of chlorophyll a and β-carotene. The absorption spectra of chlorophyll a in the visible light region decreased upon light treatment, signifying the degradation of chlorophyll a molecules. It can be inferred from these results that the THz spectra are very sensitive in monitoring the changes of the collective vibrational mode, despite the absence of changes in molecular configuration. The THz spectra can therefore be used to monitor the decomposing process of biological macromolecules; however, visible absorption spectra can only be used to monitor the breakdown extent of biological macromolecules.

  17. Predicting customers’ adoption of Islamic banking services in Tunisia:A Decomposed Theory of Planned Behaviour approach

    Directory of Open Access Journals (Sweden)

    Abdelghani Echchabi

    2015-04-01

    Full Text Available Objective -The main purpose of the study is to examine the willingness of the Tunisian customers to adopt Islamic banking services, and the factors that may influence their decision.Methods - A total of 100 questionnaires were randomly distributed to Tunisian banking customers, out of which 93 were properly filled and returned. Multiple regression and one sample t-test were subsequently applied.Results – The results showed that uncertainty, compatibility, awareness as well as subjective norm, have a significant impact on the attitude towards Islamic banking services in Tunisia. Likewise, normative belief was also found to have a significant influence on subjective norm, with particular reference to the parents, siblings, peers and colleagues, as the main referent groups. In addition, self-efficacy was found to have a significant influence on perceived behavioural control, and finally, attitude and subjective norm were found to have a significant impact on the intention to adopt Islamic banking services in Tunisia.Conclusions -Tunisian customers are willing to shift to Islamic banking services. Keywords: Tunisia, Islamic Bank, Decomposed theory of planned behaviour

  18. Effect of Land Use Pattern on Mineralization of Residual C and N from Plant Materials Decomposing Under Field Conditions

    Institute of Scientific and Technical Information of China (English)

    CHENGLILI; WENQIXIAO

    1998-01-01

    Four kinds of plant materials(astragalus,azolla,rice straw and water hyacinth) were allowed to decom-pose for 10 years in two soils with different mineralogical characteristics in fields under upland and submerged conditions.Greater amounts of C and N from azolla were retained in soils throughout the 10-year experi-mental period compared to those from the other plant materials.The residual C of all the plant materials in the two soils under upland conditions mineralized at rates corresponding to half-lives between 4.4-6.6 years,while the corresponding figures for those under submerge conditions were between 6.5-13.1 years,Minera-liztion of residual organic N followed the same pattern as residual C.Compared to residual C,however,the mineralization rates of residual organic N in most cases were significantly lower and the percentages of added N retained in soils were higher.More N from plant materials was retained in the yellow-brown soil than in the red soil,but no consistent differences in the amounts of C from plant materials and in the mineraliztion rates of both residual C and residual organic N between the wto soils could be folund.

  19. Decomposing the effect of social policies on population health and inequalities: an empirical example of unemployment benefits.

    Science.gov (United States)

    Ferrarini, Tommy; Nelson, Kenneth; Sjöberg, Ola

    2014-11-01

    The purpose of this study is to discuss and empirically contrast different conceptualizations and operationalizations of social policies in analysing health and educational differences in health cross-nationally. Country-level institutional and expenditure data on unemployment benefit schemes and individual-level data from the EU-SILC for 23 countries were used to analyse the association between unemployment benefits and self-assessed health for individuals with different educational attainment. The analyses indicate that higher coverage rate (i.e. the proportion of the relevant population eligible for benefits) is associated with better self-related health among both low- and high-educated individuals, but is not linked to smaller educational differences in health. In contrast, replacement rate (i.e. the amount of benefits received) in isolation is not related to self-assessed health. However, in countries where coverage rates are high, higher replacement rates are associated with better health among both low- and high-educated individuals and smaller educational differences in health. Decomposing unemployment benefit programmes into two main dimensions--the proportion in the labour force covered by such programmes and the replacement rate received in case of unemployment--may present further insights into institutional mechanisms linking macro-level social policies to individual-level health outcomes. © 2014 the Nordic Societies of Public Health.

  20. Evaluation of the infectivity and the persistence of Trichinella patagoniensis in muscle tissue of decomposing guinea pig (Cavia porcellus).

    Science.gov (United States)

    Fariña, F; Pasqualetti, M; Ilgová, J; Cardillo, N; Ercole, M; Aronowicz, T; Krivokapich, S; Kašný, M; Ribicich, M

    2017-01-01

    Trichinella patagoniensis, a new species of Trichinella, is widespread in Argentina. The success of parasite transmission depends, among other factors, on the resistance of L1 larvae present in the muscle tissue (ML) of dead hosts undergoing the decomposition process in different environmental conditions. The aim of the present work was to study the infectivity of T. patagoniensis muscle larvae in Cavia porcellus and the capability of the parasite to survive in decomposed muscle tissue of guinea pigs subjected to different environmental conditions. Thirty-two female Ssi:AL guinea pigs were orally inoculated with 2000 ML of T. patagoniensis (ISS2311). All the animals were sacrificed 42 days post-infection. Twenty-six animals were eviscerated, and carcasses were placed on the surface of soil inside plastic boxes that were exposed to environmental conditions in the summer 2014-2015 and autumn of 2015 in Buenos Aires, Argentina. Carcasses from six animals were placed into a plastic box inside the refrigerator at a temperature of 4 °C. The muscle tissue samples from the carcasses were examined weekly for the presence of larvae, and the infectivity of recovered ML was tested in BALB/c mice. Our results showed for the first time the ability of T. patagoniensis to complete its life cycle in guinea pigs, thus serving as a potential natural host. Also, larvae of T. patagoniensis remained infective in muscle tissue for several weeks while undergoing decomposition under different environmental conditions.