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structural evolution-enabled BiFeO3 modulated by strontium doping with enhanced dielectric,optical and superparamagnetic properties by a modified sol-gel method

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Chinese Physics B 2023年第3期32卷 521-530页

作者： sharon V s Veena Gopalan e Malini K A Department of Physics Vimala College Thrissur-9 KeralaIndia

Multiferroic(BFO)nanoparticles doped with strontium with the general formula Bi1-xsrx FeO3(x=0,0.3,0.5,0.7)were synthesized using a modified sol-gel auto-combustion *** structural,electrical,optical,and magnetic properties of the samples are *** structural analysis,carried out using the x-ray powder diffraction technique,shows a structural transition from rhombohedral(R-3c)to cubic(Pm-3m)for the doping amount of strontium(sr)equal to x=*** analysis of the prepared samples were carried out using scanning electron microscopy(seM).Frequency-dependent dielectric constant and ac conductivity were *** doped samples,with improved dielectric properties,can be used to fabricate different optoelectronic *** dielectric dis.e.sion and broad relaxation were exhibited by all the ***–Cole plots were employed as an effective tool to study the dis.e.sion parameters,namely,the optical dielectric constant,static dielectric constant,relaxation time,and spreading *** activation energy was calculated from the relaxation peaks and Cole–Cole plots,which were found to be compatible with each *** bandgap of the samples was calculated using diffuse reflectance s.e.tral(DRs)*** and strong photolumines.e.ce in the IR region was observed in the samples,similar to ZnO,which was reported for the first ***-temperature and low-temperature magnetization studies point towards the superparamagnetic nature of the samples,with an improvement in magnetic properties with *** antiferromagnetic behavior of bulk bismuth ferrite transforms to superparamagnetic in nature for both pure and sr-substituted bismuth ferrite nanoparticles due to the close dimensions of crystallite size with magnetic domains leading to the break-down of the frustrated spin cycloidal moment.

关键词： multiferroics sol-gel process x-ray s.e.tra optical and dielectric properties

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Grid Voltage sensor-less Protection sche.e for One Cycle-Controlled single-phase Photovoltaic Inverter sys.e.s

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Cs.e.Journal of Power and energy sys.e.s 2022年第6期8卷 1720-1729页

作者： Venkata R.Reddy s.e.raj e.s. are with National Institute of Technology Goa Farmagudi Ponda 403401India

One-cycle-controlled(OCC)inverters are suitable for small single-phase photovoltaic distributed-generator sys.e.s because of their simplicity,phase-locked-loop free structure,grid voltage sensor-less operation,and *** voltage sensor-less control helps reduce cost and increases reliability in *** various sensors are used for implementation of a protection *** this paper,a grid voltage sensorless protection sche.e for OCC based single-phase inverter sys.e.s is *** estimated value of voltage at point of common coupling(VPCC)is used for protecting the sys.e. during over/under voltage conditions of the grid,implementing of voltage ride through conditions,and for disconnecting the grid during islanded *** VPCC is.e.timated from the measured inverter current,switching pulses,and the measured dc-link voltage using a second-order *** and experimental studies are performed to verify the efficacy of the proposed voltage sensor-less protection mechanism triggered using estimated VPCC.

关键词： One cycle control photovoltaic sys.e.s voltage sensorless voltage protection over/under voltage protection islanding detection

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Approximate analytical solutions and mean energies of stationary schrodinger equation for general molecular potential

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Chinese Physics B 2021年第7期30卷 116-131页

作者： eyube e s Rawen B O Ibrahim N Department of Physics School of Physical SciencesModibbo Adama University of TechnologyP M B 2076 YolaAdamawa StateNigeria Directorate of Basic and Remedial studies Abubakar Tafawa Balewa University(ATBU)P M B 750001BauchiBauchi StateNigeria Department of Physics Faculty of ScienceP M B 1069MaiduguriBorno StateNigeria

The schrodinger equation is solved with general molecular potential via the improved quantization *** for bound state energy eigenvalues,radial eigenfunctions,mean kinetic energy,and potential energy are obtained in compact *** modeling the centrifugal term of the effective potential,a Pekeris-like approximation sche.e is ***,we use the Hellmann–Feynman theorem to derive the relation for expectation *** state energy eigenvalues,wave functions and meanenergies of Woods–saxon potential,Morse potential,Mobius squared and Tietz–Hua oscillators are deduced from the general molecular *** addition,we use our equations to compute the bound state energy eigenvalues and expectation values for four diatomic molecules viz.H_(2),CO,HF,and O_(2).Results obtained are in perfect agreement with the data available from the literature for the potentials and *** also show that as the vibrational quantum number increases,the mean kinetic energy for the sys.e. in a Tietz–Hua potential increases slowly to a threshold value and then *** in a Morse potential,the mean kinetic energy increases linearly with vibrational quantum number increasing.

关键词： general molecular potential schrodinger equation improved quantization rule

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exact solutions of Kolmogorov-Petrovskii-Piskunov equation Using the Modified simple equation Method

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Acta Mathematicae Applicatae sinica 2014年第3期30卷 749-754页

作者： e.M.e.Zayed s.A.Hoda Ibrahim Mathematics Department Faculty of ScienceZagazig University

The modified simple equation method is.e.ployed to find the exact solutions of the nonlinear Kolmogorov-Petrovskii-Piskunov （KPP） equation. When certain parameters of the equations are chosen to be s.e.ial values, the solitary wave solutions are derived from the exact solutions. It is shown that the modified simple equation method provides an effective and powerful mathematical tool for solving nonlinear evolution equations in mathematical physics.

关键词： modified simple equation method Kolmogorov-Petrovskii-Piskunov equation exact solutions solitary wave solutions

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应用体外胃蛋白酶法测定饲料可利用氨基酸的研究

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农业生物技术学报 1994年第2期 103-109页

作者：计成,戎易,sche.ermann,s.e.,许万根北京农业大学北京农业大学北京农业大学中国农科院畜牧所北京100094 北京100094 北京100094 北京100094

本文对体外胃蛋白酶法测定饲料干物质、粗蛋白质消化率的主要影响因素进行了研究。建立了应用体外胃蛋白酶测定饲料氨基酸消化率的方法。结果表明:在保持消化液中底物浓度为0.5％,培养温度为40℃的情况下,选择胃蛋白酶浓度为0.4％(相当... 详细信息

本文对体外胃蛋白酶法测定饲料干物质、粗蛋白质消化率的主要影响因素进行了研究。建立了应用体外胃蛋白酶测定饲料氨基酸消化率的方法。结果表明:在保持消化液中底物浓度为0.5％,培养温度为40℃的情况下,选择胃蛋白酶浓度为0.4％(相当于11.4U·mL-1消化液)、pH=1.50、培养时间为6h,对秘鲁鱼粉干物质、粗蛋白质的消化基本完全。通过测定来消化残渣部分的氨基酸含量,计算出秘鲁鱼粉的氨基酸平均消化率是94.0％。用该方法对10种不同来源、不同处理的常规蛋白质饲料氨基酸消化率测定结果,与公鸡体内法测定结果呈显著的相关（R=0.96）。

关键词：胃蛋白酶氨基酸消化率测定方法

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Numerical investigation of Reynolds number and scaling effects in microchannels flows

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Journal of Hydrodynamics 2017年第4期29卷 647-658页

作者： s.A.si salah e.G.Filali s.Djellouli Faculty of Mechanical and Process.e.gineering Houari Boumedienne University

Compared with conventional channels, experiments of microchannel often exhibit some controversial findings and sometimes.e.en opposite trends, most notably the effects of the Reynolds number and the scaled channel height on the Poiseuille number. The experimental method has still been constrained by two key facts, firstly the current ability to machine microstructures and secondly the limitation of measurement of parameters related to the Poiseuille number. As a consequence, numerical method was adopted in this study in order to analyze a flow in two-dimensional rectangular microchannels using water as working fluid. Results are obtained by the solution of the s.e.dy laminar incompressible Navier-stokes.e.uations using control volume finite element method（CVFeM） without pressure correction. The computation was made for channel height ranging from 50 ？m to 4.58 ？m and Reynolds number varying from 0.4 to 1 600. The effect of Reynolds number and channel heights on flow characteristics was investigated. The results showed that the Poiseuille numbers agree fairly well with the experimental measurements proving that there is no scale effect at small channel height. This scaling effect has been confirmed by two additional simulations being carried out at channel heights of 2.5 ？m and 0.5 ？m, res.e.tively and the range of Reynolds number was.e.tended from 0.01 up to 1 600. This study confirm that the conventional analysis approach can be employed with confidence for predicting flow behavior in microchannels when coupled with carefully matche. entrance and boundary conditions in the dimensional range considered here.

关键词： Rectangular microchannel Poiseuille number control volume finite element method(CVFeM) laminar flow minichannels

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Mid/far-infrared photo-detectors based on graphene asymmetric quantum wells

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Chinese Physics B 2016年第9期25卷 573-580页

作者： e Ben salem R Chaabani s Jaziri Institut Preparatoire aux etudes d'Ingenieurs de Tunis 2 Rue Jawaher Lel Nahrou Monfleury 1089 Tunisie Laboratoire de Physique de la Matiere Condensee Departement de Physique Faculte des Sciences de Tunis Campus Universitaire 2092 Tunisie Departement de Physique Faculte des Sciences de Bizerte Jarzouna 7021 Bizerte

We conducted a theoretical study on the electronic properties of a single-layer graphene asymmetric quantum *** of energy levels is limited by electron–hole conversion at the barrier interfaces and free-electron ***–hole conversion at the barrier interfaces can be controlled by introducing an asymmetry between barriers and taking into account the effect of the interactions of the graphene s.e.t with the *** interaction with the substrate induces an effective mass to carriers,allowing observation of Fabry–P′erot resonances under normal incidence and extinction of Klein *** asymmetry,between barriers creates a transmission gap between confined states and free-electron continuum,allowing the large graphene asymmetric quantum well to be exploited as a photo-detector operating at mid-and far-infrared frequency regimes.

关键词： graphene quantum wells reflection coefficient photo-detector

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Power Prediction of VLsI Circuits Using Machine Learning

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Computers, Materials & Continua 2023年第1期74卷 2161-2177页

作者： e.Poovannan s.Karthik Department of eCe College of Engineering and TechnologySRM Institute of Science and TechnologyVadapalani CampusChennai600026TNIndia

The difference between circuit design stage and time requirements has broadened with the increasing complexity of the circuit.A big database is needed to undertake important analytical work like statistical method,heat research,and IR-drop research that results in extended running *** unit focuses on the as.e.s.e.t of test *** of the enormous number of successful designs for currentmodels and the unnecessary time required for every test,maximum energy ratings with all tests cannot be ***,test safety is important for producing trustworthy findings to avoid loss of output and harm to the ***,effective power as.e.s.e.t is only possible in a limited sample of pre-selected ***,a key objective is to find the experiments that might give the worst situations again for testing *** offers a machine-based circuit power estimation(MLCPe)sys.e. for the selection of *** distinct techniques of predicting are ***,to find testings with power dissipation,it forecasts the behavior of ***,the changemovement and energy data are linked to the semiconductor design,identifying small problem *** types of algorithms are *** particular,the methods *** findings show great accuracy and efficiency in *** enables such methods suitable for selecting the worst s.e.ario.

关键词： Power estimation Machine learning circuit simulation VLsI implementation

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spatio-temporal evolution and influencing factors of urban green development efficiency in China

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Journal of Geographical sciences 2020年第5期30卷 724-742页

作者： ZHOU Liang ZHOU che.ghu che.Lei WANG Bao Faculty of Geomatics Lanzhou Jiaotong UniversityLanzhou 730070China state Key Laboratory of Resources and environmental Information sys.e. Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China school of Architecture and Urban Planning Nanjing UniversityNanjing 210093China Northwest Institute of eco-environment and Resources CASLanzhou 730000China

To resolve conflicts between development and the preservation of the natural environment,enable economic transformation,and achieve the global sustainable development goals(sDGs),green development(GD)is gradually becoming a major strategy in the construction of an ecological civilization and the ideal of building a"beautiful China",alongside the transformation and reconstruction of the global *** on a combination of the concept and implications of GD,we first used the slacks Based Model with undesirable outputs(sBM-Undesirable),the Theil index,and the spatial Markov chain to measure the spatial patterns,regional differences,and spatio-temporal evolution of urban green development efficiency(UGDe)in China from 2005 to ***,by coupling natural and human factors,the mechanism influencing UGDe was quantitatively investigated under the framework of the human-environment *** results showed that:(1)from 2005 to 2015,the UGDe increased from 0.475 to 0.523,i.e.,an overall increase of 10%.In terms of temporal variation,there was a staged increase,with its.e.olution having the characteristics of a"W-shaped"pattern.(2)The regional differences in UGDe followed a pattern of eas.e.n>central>*** different types of urban agglomeration,the UGDe had inverted pyramid clus.e. growth characteristics that followed a pattern of"national level>regional level>local level",forming a stable hierarchical scale structure of"super cities>mega cities>big cities>medium cities>small cities".(3)UGDe in China has developed with significant spatial agglomeration ***-efficiency type cities have positive spillover effects,while low-efficiency cities have negative *** types of urban evolution proces.e. have a path dependence,and a spatial club convergence phenomenon exists,in which areas with high UGDe are concentrated and drive low UGDe elsewhere.(4)Under the framework of regional human-environment interaction,the degree of human and soc

关键词： green development efficiency green city green economy spatial scale sustainable development goals(sDGs)

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Determination of a Reasonable Percentage for ecological Water-Use in the Haihe River Basin, China

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Pedosphere 2006年第1期16卷 33-42页

作者： XIA Jun FeNG Hua-Li ZHAN che.s.e.g NIU Cun-Wen Key Laboratory of Water Cycle ＆ Related Land surface Proces.e. Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Science Beijing 100101 （China）. state Key Laboratory of Water Resources ＆ Hydropower engineering sciences Wuhan University Wuhan 430072（China） Nanjing Hydraulic Research Institute Nanjing 210029 （China）

An investigation was conducted to study problems of determining a reasonable percentage for ecological water-use in the Haihe River Basin of China. Three key as.e.ts for the ecological water requirement （eWR） were analyzed, involving i） the eWR for river sys.e., ii） the eWR for wetlands and lakes, and iii） the eWR for discharge into the sea to maintain the estuary ecological balance of the Haihe River. The Montana method and related water level-flow relationships, and the statistic approach based on hydrological records were applied to estimate different components of eWR. The results showed that the total ecological water demand in the region, was about 3.47-14.56 billion m^3. Considering flow regime change and uncertainty, the ecological water demand could be estimated by the hydrological frequency approach. Preliminary analysis showed that for different annual runoff under the frequencies of 20%, 50%, 75% and 95%, the ecological water demand approache. 12%-50%, 18%-74%, 24%-103%, 35%-148% and 16%-66%, res.e.tively. By further analysis to balance ecological water-use and socioeconomic water-use, the rational percentage of ecological water-use was.e.timated as 35%-74%, that provides useful information to judge whether the allocation of water resources is reasonable, and was proved to be satisfactory by comparing with the practical condition.

关键词： ecological water requirement ecological water-use Haihe River Basin

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