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Journal of Advanced Dielectrics 2021年第4期11卷 37-45页

作者： Abdul Manan Maqbool Ur Rehman Atta Ullah arbab Safeer Ahmad Yaseen iqbal ibrahim Qazi Murad Ali Khan Hidayat Ullah Shah Arshad Hussain Wazir Laboratory for Research in Advanced Materials Department of Physics University of Science and Technology BannuTownship Bannu 28100 Khyber PakhtunkhwaPakistan Center for Material Science Islamia College Peshawar Peshawar25120 Khyber PakhtunkhwaPakistan Materials Research Laboratory Department of Physics University of Peshawar25120 KPPakistan§Department of Materials Science and EngineeringInstitute of Space Technology Islamabad44000 IslamabadPakistan Department of Chemistry University of Science and Technology Bannu 28100 Khyber PakhtunkhwaPakistan

Ceramics-based capacitors with excellent energy storage characteristics,fast charging/discharge rate,and high efficiency have received significant *** this work,Na0.73Bi0.09NbO3(NBN)ceramics were processed through solid-state sintering *** investigated ceramics were crystallized in a single perovskite *** microstructure,with small average grain size(~0.92 mm)is obtained for the investigated ceramics.A high dielectric constant>1000 accompanied by a low dielectric loss was achieved for these ceramics at ambient temperature.A recoverable energy density~0.92 J/cm3 and ultra-high efficiency of 96.33%at 138 kV/cm were obtained at room ***,a lower discharging time of 0.14 ms was also *** material is a suitable candidate for power pulsed applications.

关键词： Polarization energy density capacitor efficiency

Dynamic responses of a sediment-filled valley with a fluid layer subject to incident waves

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Earthquake Engineering and Engineering Vibration 2011年第2期10卷 175-185页

作者： Wen-i Liao Taipei University of Technology (NTUT)

The diffraction of elastic waves by a sedimentary valley in a homogeneous elastic half-space is studied in this paper. The sediment-filled valley is composed of a fluid layer over a soft soil deposit whose characteristics may be significant and should be carefully considered when designing long span bridges with high piers. The method of analysis adopted in the paper is to decompose the problem into an interior region and an exterior region. in the exterior region, the scattered wave fields are constructed with the linear combinations of two independent sets of Lamb＇s singular solutions, i.e., the integral solutions for two concentrated surface loads in two directions; and their derivatives are used to represent the scattered wave fields. A technique is proposed to calculate the integrals in the wave-number domain based on the method of steepest descent. For the interior region, the wave fields for the fluid layer and soft soil deposit are expressed in terms of wave functions which satisfy the equation of motion. The continuity condition at the interface of the media is satisfied in the least square sense. The effects of geometric topography, soil amplification and fluid layer subject to different types of incident harmonic plane waves are analyzed and discussed..

关键词： sedimentary valley scattered wave least square

influence of the chromium and ytterbium co-doping on the photoluminescence of zinc selenide crystals

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Journal of Rare Earths 2014年第10期32卷 938-945页

作者： i.Radevici Wihuri Physical Laboratory Department of Physics and AstronomyUniversity of Turku Faculty of Physics and Engineering Moldova State University

The luminescent properties of ZnSe, ZnSe：Cr（0.05 at.% Cr）, ZnSe：Yb（0.03 at.% Yb） and ZnSe：Cr：Yb（0.05 at.% Cr, 0.05 at.% Yb） crystals, doped during the growth process by the chemical vapor transport method, were studied within the temperature interval of 6–300 K. At the 6 K temperature in the visible spectral range 2 bands were observed： a band in the excitonic spectral region and a band of self-activated luminescence. it was shown that co-doping of zinc selenide crystals with the chromium and ytterbium led to the combination of the impurities influence on the photoluminescent properties. At the liquid helium temperature in the middle infrared range of the spectra of the ytterbium and chromium co-doped crystal a band with the maximum localized at 1.7μm was observed, which was overlapped with a complex band in the middle-iR spectral range, characteristic for the chromium doped ZnSe crystals. On the basis of obtained data an interaction mechanism of the chromium and ytterbium co-doping impurities was proposed. Guided by the existent model of the ytterbium ion incorporation in the selenide sublattice of the ZnSe crystals, an assumption about stabilization of single charged chromium ions in the zinc sublattice crystal nodes, by means of formation of the local charge compensating clusters, was made. it was assumed that the resonant energy transfer from one chromium ion to another,which led to the concentration quenching of the iR emission in the ZnSe：Cr PL spectra, would lead to the broadening of the iR emission in the spectra of ytterbium and chromium co-doped zinc selenide crystals.g

关键词： ZnSe luminescence co-doping defects Cr Yb rare earths

Crossover of large to small radius polaron in ionic crystals

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Chinese Physics B 2016年第11期25卷 434-440页

作者： M i Umo Department of Physics University of Calabar PMB 1115 Nigeria

The crossover of large to small radius polaron is studied in terms of the inverse-relaxation time and *** is found that the small radius polaron exists at higher temperature than the large radius polaron.A formula which relates the inverse-relaxation time to the ratio of arbitrary temperature and Debye temperature of the crystal is *** polaron crossover temperatures in NaCl and KBr are found from plotted *** straight line emerging at the Debye temperature T_d of a graph reflects the increase of the inverse relaxation time for increasing temperature up to the collapse of the small radius *** relationship between the small and large radius polarons is found and known ratios of the effective and the bare masses of the electrons for the two substances are used to validate our *** small radius polaron＇s mass is later compared with the mass obtained from the hopping formula and is found to be approximately ***,we point out that the crossover temperature is material-specific since it depends on the Debye and the effective dielectric function.

关键词： relaxation radius crossover inverse straight ionic validate arbitrary phonon dielectric

Optimal Combined Heat and Power Economic Dispatch Using Stochastic Fractal Search Algorithm

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Journal of Modern Power Systems and Clean Energy 2020年第2期8卷 276-286页

作者： Muwaffaq i.Alomoush the Department of Electrical Power Engineering Hijjawi Faculty for Engineering TechnologyYarmouk UniversityIrbidJordan

Combined heat and power(CHP)generation is a valuable scheme for concurrent generation of electrical and thermal *** interdependency of power and heat productions in CHP units introduces complications and non-convexities in their modeling and *** paper uses the stochastic fractal search(SFS)optimization technique to treat the highly non-linear CHP economic dispatch(CHPED)problem,where the objective is to minimize the total operation cost of both power and heat from generation units while fulfilling several operation interdependent limits and *** CHPED problem has bounded feasible operation regions and many local *** SFS,which is a recent metaheuristic global optimization solver,outranks many current reputable *** constraints of the CHPED is achieved by employing external penalty parameters,which penalize infeasible solution during the iterative *** confirm the strength of this algorithm,it has been tested on two different test systems that are regularly *** obtained outcomes are compared with former outcomes achieved by many different methods reported in literature of *** results of this work affirm that the SFS algorithm can achieve improved near-global solution and compare favorably with other commonly used global optimization techniques in terms of the quality of solution,handling of constraints and computation time.

关键词： Combined heat and power(CHP) economic dispatch global optimization metaheuristic algorithms non-convex optimization problem power systems stochastic fractal search

Selective catalytic reduction of NOX with ethanol and other C1-4 oxygenates over Ag/Al2O3 catalysts: A review

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Frontiers of Chemical Science and Engineering 2020年第4期14卷 471-491页

作者： Pavlo i.Kyriienko L.V.Pisarzhevskii institute of Physical Chemistry of the NAS of Ukraine Kyiv 03028Ukraine

Research results regarding selective catalytic reduction(SCR)of NOx with ethanol and other C1-4 oxygenates as reductants over silver-alumina catalysts are *** aspects of the process mechanism,nature of active sites,role of alumina and silver(especially in the formation of bifunctional active sites),effects of reductants and reaction conditions are *** has been determined that key stages of the process include formation of reactive enolic species,their interaction with NOx and formation of nitroorganic compounds which transform to NCOads species and further to *** results obtained over various silver-alumina catalysts demonstrate the perspectives of their application for reducing the level of nitrogen oxides in engine emissions,including in the presence of water vapor and sulfur *** to improve the catalysts for the SCR of NOx with C1-4 oxygenates are outined.

关键词： SCR nitrogen oxides silver-alumina catalyst silver species ethanol oxygenates

Explosive-Emission Plasma Dynamics in ion Diode in Double-Pulse Mode

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Plasma Science and Technology 2011年第6期13卷 698-701页

作者： Alexander i.PUSHKAREV Yulia i.iSAKOVA Tomsk Polytechnic University

The results of an experimental investigation of explosive-emission plasma dynamics in an ion diode with self-magnetic insulation are presented. The investigations were accomplished at the TEMP-4M accelerator set in a mode of double pulse formation. Plasma behaviour in the anode-cathode gap was analyzed according to both the current-voltage characteristics of the diode （time resolution of 0.5 ns） and thermal imprints on a target （spatial resolution of 0.8 mm）. it was shown that when plasma formation at the potential electrode was complete, and up until the second （positive） pulse, the explosive-emission plasma expanded across the anode-cathode gap with a speed of 1.3±0.2 cm/μs. After the voltage polarity at the potential electrode was reversed （second pulse）, the plasma erosion in the anode-cathode gap （similar to the effect of a plasma opening switch） occurred. During the generation of an ion beam the size of the anode-cathode gap spacing was determined by the thickness of the plasma layer on the potential electrode and the layer thickness of the electrons drifting along the grounded electrode.

关键词： ion beams graphite cathodes plasma speed self-magnetic insulation

Could androgens maintain specific domains of mental health in aging men by preserving hippocampal neurogenesis

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Neural Regeneration Research 2012年第28期7卷 2227-2239页

作者： Mark i Ransome Florey Neurosciences institute Melbourne Brain Centre the University of Melbourne

interest surrounds the role of sex-hormones in regulating brain function outside of reproductive behaviour. Declining androgen production in aging males has been associated with cognitive impairment, depression and increased risk of developing Alzheimer＇s disease. indication for testosterone replacement therapy is based on biochemically determined low circulating testosterone combined with manifest symptoms. However, which aspects of age-related cognitive decline are attributable to low circulating testosterone remain ambiguous. Studies examining cognition in aging men receiving testosterone replacement therapy have yielded equivocal results. The exact role of testosterone in maintaining cognitive function and the underlying neural mechanisms are largely unknown, though it would appear to be domain specific. Cladty in this area will provide clinical direction toward addressing an increasing healthcare burden of mental health decline coincident with increasing longevity. The premise that androgens contribute to maintaining aspects of mental health in aging men by preserving hippocampal neurogenesis will be used as a forum in this review to discuss current knowledge and the need for further studies to better define testosterone replacement strategies for aging male health.

关键词： androgen hippocampus neurogenesis aging cognition male testosterone

Optimized guided mode resonant structure as thermooptic sensor and liquid crystal tunable filter

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Chinese Optics Letters 2009年第8期7卷 667-670页

作者： i.Abdulhalim Department of Electrooptic Engineering Ben Gurion University of the Negev

Applicability of guided mode resonant structures to tunable optical filtering and sensing is demonstrated using nematic liquid crystals. As a sensor, a minimum refractive index detectivity of 10^-5 is demonstrated while as a tunable filter, tunability range of few tens of nanometers with 2-nm bandwidth is presented. The optimum design is achieved by maximizing the evanescent field region in the analyte which maximizes the overlap integral. The device can be operated in reflection or transmission modes at normal incidence. it can also be operated at a single wavelength by measuring the angular profile of the light beam.

关键词： mode Optimized guided mode resonant structure as thermooptic sensor and liquid crystal tunable filter

Test measurements for accuracy of absolute and relative GPS positioning

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中国有色金属学会会刊：英文版 2005年第S1期15卷 299-303页

作者： i. Havasi University of Miskolc Hungary

The paper, after the introduction, briefly outlines the principles of both absolute and relative GPS positioning. it deals with factors and error resources affecting the accuracy of these surveying procedures. it reviews the geodetic determination of a reference point and a base line used for the test measurements. The study describes the completed test measurements, and on the basis of results, it draws the conclusions for the accuracy of the investigated surveying methods. Finally, considering these accuracy measures, their possible application in mine surveying is also mentioned very shortly.

关键词： GPS surveying methods factors and errors test measurements accuracy