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Composition-tailor induced electrocaloric effect near room temperature in(Pb,Ba)HfO_(3)films

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Journal of Materiomics 2023年第3期9卷 502-509页

作者： Xian-Xiong Huang peng-zu ge Tian-Fu Zhang Qiu-Xiang Liu Yan-Ping Jiang Zhen-Hua Tang Xiao-Bin Guo Xin-Gui Tang School of Physics&Optoelectric Engineering Guangdong University of TechnologyGuangzhou510006China Jewelry Institute Guangzhou Panyu PolytechnicGuangzhou511483China School of Materials Science and Engineering Harbin Institute of TechnologyShenzhenGuangdong518055China

More and more researchers start to pay attention to the electrocaloric temperature change(DT)in polar materials,which is caused by an applied electric *** this paper,Ba-doped PbHfO_(3)(PBH)films were prepared by sol-gel *** components,microstructures,dielectric polarization and electro-caloric effects(ECEs)were *** the addition of Ba^(2+),PBH films went from antiferroelectric(AFE)to ferroelectric(FE).At the same time,their dielectric peaks shifted toward lower *** maximum DT obtained in Pb_(0.8)Ba_(0.2)HfO_(3)FE film is 41.1 K,which is an order of magnitude larger than PbHfO_(3)film(△Tge polarization change and high△T,which is needed in solid-state cooling devices.

关键词： Ferroelectric Electrocaloric effects Landau-Devonshire theory Solid-state cooling

Excellent energy storage properties realized in novel BaTiO_(3)-based lead-free ceramics by regulating relaxation behavior

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Journal of Materiomics 2023年第5期9卷 910-919页

作者： peng-zu ge Zhi-Gang Liu Xian-Xiong Huang Xin-Gui Tang Zhen-Hua Tang Shui-Feng Li Qiu-Xiang Liu Yan-Ping Jiang Xiao-Bin Guo School of Physics&Optoelectric Engineering Guangdong University of TechnologyGuangzhou Higher Education Mega CenterGuangzhou510006China Guangzhou Panyu Polytechnic Guangzhou511483China

BaTiO_(3)(BT)has attracted extensive attention among advanced lead-free ferroelectric materials due to its unique dielectric and ferroelectric ***,the enormous remanent polarization and coercive field severely impede the improvement of its energy storage ***,the BaTiO_(3)e-Bi(Zn_(0.5)Hf_(0.5))O_(3)(BT-BZH)ceramics with high breakdown field strength and remarkable relaxation characteristics can be obtained by introducing the composite component BZH in BT to regulate the phase structure and grain size of the *** findings demonstrate that the improvement of energy storage performance is related to the increase of relaxation behavior.A large energy storage density(Wrec~3.62 J/cm^(3))along with superior energy storage efficiency(h~88.5%)is achieved in 0.88BT-0.12BZH relaxor ceramics only at 240 kV/*** addition,the sample suggests superior thermal stability and frequency stability within 25e115℃and 1e500 Hz,***,the outstanding chargedischarge properties with an ultrafast discharge time(100 ns),large discharged energy density(1.2 J/cm^(3)),impressive current density(519.4 A/cm^(2))and power density(31.1 MW/cm^(3))under the electric field of 120 kV/cm are achieved in studied *** excellent energy storage performance of BT-BZH ceramics provides a promising platform for the application of lead-free energy-storage materials.

关键词： BT-based ceramics Relaxor Energy storage Charge-discharge

Composition dependence of giant electrocaloric effect in PbxSr1-xTiO_(3) ceramics for energy-related applications

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Journal of Materiomics 2019年第1期5卷 118-126页

作者： peng-zu ge Xiao-Dong Jian Xiong-Wei Lin Xin-Gui Tang Zhi Zhu Qiu-Xiang Liu Yan-Ping Jiang Tian-Fu Zhang Sheng-Guo Lu School of Physics and Optoelectric Engineering Guangdong University of TechnologyGuangzhou Higher Education Mega CentreGuangzhou510006China School of Materials and Energy Guangdong University of TechnologyGuangzhou Higher Education Mega CentreGuangzhou510006China

Pb_(x)Sr_(1-x)TiO_(3)(x=0.30,0.35,0.40,0.45,0.50 and 0.55)ceramics were fabricated by a solid-state reaction *** diffraction data at room temperature show PST samples shift from cubic to tetragonal phase with the increase of Pb^(2+) *** microstructures were observed by scanning electron *** measurement was employed to investigate the ferroelectriceparaelectric phase transition *** dependent polarizationeelectric field hysteresis loops were conducted to study the electrocaloric effect(ECE)of the ferroelectric ceramics by indirect methods over a wide temperature *** measurement of temperature change(DT)at room temperature for all samples can achieve 0.79e1.86 ***'s more,a giant ECE(△T=2.05 K,EC strength(△T/△E)=0.51×10^(-6) K m/V,under 40 kV/cm)was obtained in the sample of x=0.35 near phase transition *** results suggest that the ceramics are promising cooling materials with excellent EC properties for energy related applications.

关键词： Pb_(x)Sr_(1-x)TiO_(3)ceramics Electrocaloric effect Phase transition Energy applications

基于马尔可夫链的COVID-19流行病患病区域变化趋势预测

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陕西科技大学学报 2025年第1期43卷 211-218页

作者：王鑫王令戈师鹏柔陕西科技大学电子信息与人工智能学院陕西西安710021

在COVID-19疫情环境下,为精准预测不同症状状态的人群人数和区域级别的发展趋势,以SIR传染病模型为基础,基于马尔可夫链预测时空相关的特性,设计了感染人群状态与管控措施相关的K-SIRD传染病预测模型.根据COVID-19疫情人群之间传染性的... 详细信息

在COVID-19疫情环境下,为精准预测不同症状状态的人群人数和区域级别的发展趋势,以SIR传染病模型为基础,基于马尔可夫链预测时空相关的特性,设计了感染人群状态与管控措施相关的K-SIRD传染病预测模型.根据COVID-19疫情人群之间传染性的特征及受距离影响造成有效传染数R e的变化而导致不同的症状状态改变的转移规律,实时精准预测了不同状态的人员人数变化,并根据同一区域人群症状状态分布情况不同,针对不同级别的区域采用不同等级的管控措施.

关键词： K-SIRD模型 COVID-19 马尔可夫链有效繁殖数

Effect of^3B Group in Rings on Special Dispersion of B2O3-SiO2-ZrO2-Ta2O5-Na2O System Glass

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Journal of Wuhan University of Technology(Materials Science) 2018年第5期33卷 1032-1038页

作者： XU Xiaodian WANG Yanhang zu Chengkui ZHOU peng China Building Materials Academy Beijing 100024China

Borosilicate glasses,with x B2O3-（60-x）SiO2-8ZrO2-8Ta2O5-24Na2O（7≤x≤59 mol%）composition,were fabricated by melt-quenching ***,UV-Vis,Raman and IR spectroscopic studies were utilized to investigate the structure of fabricated *** NMR spectrum was deconvoluted into five Gaussian bands,assigned to ^4B（0B,4Si）,^4B（1B,3Si）,^4B（2B,2Si）,^3B（rings）and ^3B（loose）,to get their quantitative *** relative dispersion deviation？P（g,F） was attributed to the relative quantity of ^3B（rings）but not all ^3B groups,and B2O3 existed mainly as[BO3]in rings firstly,and then as[BO3]in loose *** UV-Vis spectra revealed that the quantity of non-bridging oxygen increased firstly and then decreased with increasing concentration of *** as complementary techniques,Raman and IR measurements revealed that four-coordinated boron and silica mainly existed as ^4B-O-B,and Si-O-Si in Q^2,respectively,as chain structure but not framework structure,and[B？4]units prefered connections with borate rather than with silicate entities of the glass network in these studied *** addition,the conclusion also certified that ^3B in＂loose＂condition located in lower wavenumbers between 1 200-1 600 cm^-1 in Raman spectra.

关键词： borosilicate glass structure NMR Raman relative dispersion deviation

Periodic Solutions to a Kind of Second Order Neutral Functional Differential Equation in the Critical Case

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Acta Mathematica Sinica,English Series 2005年第5期21卷 1149-1158页

作者： Shi Ping LU Wei Gao ge zu Xiu ZHENG Department of Mathematics Anhui Normal University Wuhu 241000 P. R. China Department of Applied Mathematics Beijing Institute of Technology Beijing 100081 P. R. China Department of Mathematics Anhui University Hefei 230039 P. R. China

In this paper, the authors consider the existence of periodic solutions for a kind of second neutral functional differential equation as follows：（x（t） - cx（t -τ）＂ = g（t, x（t - μ（t）））＋ e（t）,in the critical case ｜c｜ = 1. By employing Mawhin＇s continuation theorem and some analysis techniques, some new results are obtained.

关键词： Periodic solution Mawhin's continuation theorem Neutral functional differential equation in the critical case

Adaptive fuze-warhead coordination method based on BP artificial neural network

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Defence Technology（防务技术） 2023年第11期29卷 117-133页

作者： peng Hou Yang Pei Yu-xue ge School of Aeronautics Northwestern Polytechnical UniversityXi'an710072ShaanxiChina

The appropriate fuze-warhead coordination method is important to improve the damage efficiency of air defense missiles against aircraft targets. In this paper, an adaptive fuze-warhead coordination method based on the Back Propagation Artificial Neural Network(BP-ANN) is proposed, which uses the parameters of missile-target intersection to adaptively calculate the initiation delay. The damage probabilities at different radial locations along the same shot line of a given intersection situation are calculated, so as to determine the optimal detonation position. On this basis, the BP-ANN model is used to describe the complex and highly nonlinear relationship between different intersection parameters and the corresponding optimal detonating point position. In the actual terminal engagement process, the fuze initiation delay is quickly determined by the constructed BP-ANN model combined with the missiletarget intersection parameters. The method is validated in the case of the single-shot damage probability evaluation. Comparing with other fuze-warhead coordination methods, the proposed method can produce higher single-shot damage probability under various intersection conditions, while the fuzewarhead coordination effect is less influenced by the location of the aim point.

关键词： Aircraft vulnerability Fuze-warhead coordination BP artificial neural network Damage probability Initiation delay

Comparison of Controlling Parameters for Near-Equatorial Tropical Cyclone Formation between Western North Pacific and North Atlantic

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Journal of Meteorological Research 2021年第4期35卷 623-634页

作者： Changhao LU Xuyang ge Melinda peng Key Laboratory of Meteorological Disaster of Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China University of Colorado Colorado SpringColorado 80918USA

In this study,the differences in spatial distribution and controlling parameters for the formation of near-equatorial tropical cyclones(NETCs)between the western North Pacific(WNP)and the North Atlantic(NA)are *** exhibit distinctive spatial variabilities in different *** the past few decades,the majority of NETCs took place in WNP while none was observed in *** mechanism behind such a distinguishing spatial distribution difference is analyzed by using statistical *** is noted that the dynamical variables such as low-level relative vorticity and vertical wind shear(VWS)are likely the primary controlling *** with NA,larger low-level vorticity and smaller VWS appear over *** increase of vorticity attributes a lot to the turning of northeast trade *** in WNP tend to occur in the areas with VWS less than 9 m s^(-1),while the VWS in NA generally exceeds 10 m s^(-1).On the other hand,the sea surface temperature in the near-equatorial region of both of the two oceans exceeds 26.5℃and the difference of mid-level moisture is not significant;thus,thermal factors have little contribution to the distinction of NETC activities between WNP and *** oscillation(ISO)and synoptic-scale disturbances in WNP are also shown to be more favorable for NETC *** NETCs were generated in ISO active ***-scale disturbances in WNP obtain more energy from the mean flows through the barotropic energy conversion *** overall unfavorable thermal and dynamic conditions lead to the absence of NETCs in NA.

关键词： near-equatorial tropical cyclone(NETC) cyclogenesis genesis potential index(GPI)

Terminal attitude selection method of missile attack aircraft

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Chinese Journal of Aeronautics 2024年第2期37卷 385-400页

作者： peng HOU Yang PEI Yuxue ge Mengjie ZHU School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Research Department Shanghai Electro-Mechanical Engineering InstituteShanghai 201108China

The appropriate terminal attitude of missile is important to improve the damage effectiveness of fragmentation warhead against aircraft *** this paper,three missile terminal attitude selection methods are proposed to solve the problem of terminal attitude selection in different situations according to their respective evaluation *** MVE-based method uses the damage probability of each detonation point around the aircraft at a given attitude of missile to calculate the Mean Volume of Effectiveness(MVE)at the corresponding attitude,and then uses the MVE for different attitudes to select the terminal strike *** detonation position-based method addresses the case where the missile detonation position can be assessed in *** the effects of missile guidance errors and fuze activation position errors,Monte Carlo simulations are used to calculate the damage probability of aircraft with different strike attitudes,from which the terminal strike attitude is *** BP-ANN model-based method uses the constructed Back Propagation Artificial Neural Network(BP-ANN)model instead of simulation to calculate the evaluation indexes in the corresponding cases of MVE-based method and Detonation position-based method,which can improve the efficiency of attitude *** are conducted for different scenarios to verify the feasibility and effectiveness of the proposed method.

关键词： Aircraft vulnerability Attitude selection BP-ANN Damage probability Damage effectiveness