1,186 research outputs found

    Electrochemical and optical studies on photoactive BiVO4-TiO2/poly 3,4-ethylenedioxythiophene assemblies in gel electrolyte: Role of inorganic/organic interfaces in surface functionalization

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    Inorganic/organic interface assemblies were created from poly 3,4-ethylenedioxythio­phene (PEDOT) interfaced with amorphous BiVO4 and with BiVO4-TiO2. Electrochemical cells-based thermoplastic gel electrolytes containing KI/I2 were used to study the photoelectrochemical behavior of the Inorganic/organic interface electrodes. Optical studies show that doping BiVO4 with TiO2 narrowed the optical band gap to allow more absorption in the visible region and increases solar energy conversion. Evidence for both direct and indirect band gaps was observed. Refractive index data indicates that BiVO4 and BiVO4/TiO2 obey the anomalous dispassion multiple-oscillator model. Chronoampero­metry of these assemblies shows the phenomena of dark current, which correlates to the presence of random electron/hole generation in the depletion layer. PEDOT enhances the photoactivity of BiVO4 only. Electrochemical impedance spectroscopy studies indicated that both kinetic and diffusional control at high and low frequencies, respectively. Furthermore, studies show that as frequency increases, the conductivity increases due to dispersion and charge carrier hopping. All photoactivity outcomes were reproducible

    Biological Control of Brown Leaf Spot Disease Caused by Curvularia Lunata and Field Application Method on Rice Variety IR66 in Cambodia

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    Curvularia lunata was found to cause a serious rice brown leaf spot in Cambodia. This is the first report of brown leaf spot on rice in Cambodia. All isolates were tested for pathogenicity. Dual culture antagonistic tests showed that Chaetomium cupreum inhibited sporulation of C. lunata when compared to the control. In a pot experiment, C. cupreum significantly reduced the incidence of brown leaf spot caused by C. lunata. After application of a spore suspension of C. cupreum, Chaetomium-biofungicide and chemical fungicide (tebuconazole) to rice seedlings inoculated with C. lunata, the disease was reduced by 68.79 %, 75.80 % and 72.41 %, respectively. In a field trial, the chemical method gave the best results in all plant parameters, followed by the good agricultural practice (GAP) and organic methods. The chemical method gave the highest panicle/plant, panicle length, panicle weight, grain weight/plant which were different from the GAP and organic methods. The chemical method also gave the best results in filled grain panicle-1, unfilled grain panicle-1, grain weight plot-1, dry hay weight plot-1, biomass weight plot-1 and harvest index, and was significantly better than the GAP and organic methods

    Mean Drift Length During a Semi Wave of the CW Radio-Frequency Field

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    In this work we study mean drift length during a semi wave of the CW radiofrequency field the behavior of the diffusion particles in the pure Helium gas whose plays important role in production of the lam ps such as glow lamps and gas lasers through the calculation of the transport parameters which are w, μ, and D by solving numerically transport equation and feeding it to computer program which is construction to calculate the following parameters: E/P300, S, DN, Dp, n, c , l, w, a, SE, (fn1P), (fn1P)-1, w/p and p/w for energy ranges 0.121´10-18 £ E/N £ 0.303 ´10-16 V.cm2 at temperature 300°K. These parameters represented as functions for their variables whose shows a good agreement with experimental and theoretical data

    The role of death-associated protein 3 in apoptosis, anoikis and human cancer

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    Death-associated protein 3 (DAP3) is a molecule with a significant role in the control of both apoptosis and anoikis. Apoptosis is the predominant type of programmed cell death (PCD) which may occur in response to irreparable damage to DNA, or in response to induction by inflammatory cells. Anoikis is subset of apoptosis which occurs in epithelial cells in response to detachment from the surrounding matrix. Both apoptosis and anoikis are of interest in the context of carcinogenesis. In this review, we shall discuss apoptosis and anoikis, and the recent literature regarding the role of DAP3 in both these pathways

    The status of GEO 600

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    The GEO 600 laser interferometer with 600m armlength is part of a worldwide network of gravitational wave detectors. GEO 600 is unique in having advanced multiple pendulum suspensions with a monolithic last stage and in employing a signal recycled optical design. This paper describes the recent commissioning of the interferometer and its operation in signal recycled mode

    Improving the sensitivity to gravitational-wave sources by modifying the input-output optics of advanced interferometers

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    We study frequency dependent (FD) input-output schemes for signal-recycling interferometers, the baseline design of Advanced LIGO and the current configuration of GEO 600. Complementary to a recent proposal by Harms et al. to use FD input squeezing and ordinary homodyne detection, we explore a scheme which uses ordinary squeezed vacuum, but FD readout. Both schemes, which are sub-optimal among all possible input-output schemes, provide a global noise suppression by the power squeeze factor, while being realizable by using detuned Fabry-Perot cavities as input/output filters. At high frequencies, the two schemes are shown to be equivalent, while at low frequencies our scheme gives better performance than that of Harms et al., and is nearly fully optimal. We then study the sensitivity improvement achievable by these schemes in Advanced LIGO era (with 30-m filter cavities and current estimates of filter-mirror losses and thermal noise), for neutron star binary inspirals, and for narrowband GW sources such as low-mass X-ray binaries and known radio pulsars. Optical losses are shown to be a major obstacle for the actual implementation of these techniques in Advanced LIGO. On time scales of third-generation interferometers, like EURO/LIGO-III (~2012), with kilometer-scale filter cavities, a signal-recycling interferometer with the FD readout scheme explored in this paper can have performances comparable to existing proposals. [abridged]Comment: Figs. 9 and 12 corrected; Appendix added for narrowband data analysi

    Search for gravitational wave bursts in LIGO's third science run

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    We report on a search for gravitational wave bursts in data from the three LIGO interferometric detectors during their third science run. The search targets subsecond bursts in the frequency range 100-1100 Hz for which no waveform model is assumed, and has a sensitivity in terms of the root-sum-square (rss) strain amplitude of hrss ~ 10^{-20} / sqrt(Hz). No gravitational wave signals were detected in the 8 days of analyzed data.Comment: 12 pages, 6 figures. Amaldi-6 conference proceedings to be published in Classical and Quantum Gravit

    Upper limits on the strength of periodic gravitational waves from PSR J1939+2134

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    The first science run of the LIGO and GEO gravitational wave detectors presented the opportunity to test methods of searching for gravitational waves from known pulsars. Here we present new direct upper limits on the strength of waves from the pulsar PSR J1939+2134 using two independent analysis methods, one in the frequency domain using frequentist statistics and one in the time domain using Bayesian inference. Both methods show that the strain amplitude at Earth from this pulsar is less than a few times 102210^{-22}.Comment: 7 pages, 1 figure, to appear in the Proceedings of the 5th Edoardo Amaldi Conference on Gravitational Waves, Tirrenia, Pisa, Italy, 6-11 July 200

    Quantum state preparation and macroscopic entanglement in gravitational-wave detectors

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    Long-baseline laser-interferometer gravitational-wave detectors are operating at a factor of 10 (in amplitude) above the standard quantum limit (SQL) within a broad frequency band. Such a low classical noise budget has already allowed the creation of a controlled 2.7 kg macroscopic oscillator with an effective eigenfrequency of 150 Hz and an occupation number of 200. This result, along with the prospect for further improvements, heralds the new possibility of experimentally probing macroscopic quantum mechanics (MQM) - quantum mechanical behavior of objects in the realm of everyday experience - using gravitational-wave detectors. In this paper, we provide the mathematical foundation for the first step of a MQM experiment: the preparation of a macroscopic test mass into a nearly minimum-Heisenberg-limited Gaussian quantum state, which is possible if the interferometer's classical noise beats the SQL in a broad frequency band. Our formalism, based on Wiener filtering, allows a straightforward conversion from the classical noise budget of a laser interferometer, in terms of noise spectra, into the strategy for quantum state preparation, and the quality of the prepared state. Using this formalism, we consider how Gaussian entanglement can be built among two macroscopic test masses, and the performance of the planned Advanced LIGO interferometers in quantum-state preparation
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