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Enhanced electric-field induced strain in Eu^(3+) doped 0.67BiFeO_(3)-0.33BaTiO_(3) lead-free piezoelectric ceramics

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Journal of Rare Earths 2024年第9期42卷 1747-1754,I0004页

作者： Wei Li Tongxiang Liang Xiang He vyunov oleg Dongfang Pang Shan Wu College of Rare Earths Jiangxi University of Science and TechnologyGanzhou341000China Key Laboratory of High Performance Ceramics and Ultrastructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai201800China

Lead-free ferroelectric ceramics,0.67Bi_(1-x)Eu_(x)FeO_(3)-0.33BaTiO_(3)(BF-BT-xEu,x=0-0.02),were prepared via a solid-state reaction,The effect of Eu^(3+) doping on the microstructure,dielectric properties,ferroelectric properties,and electric-field-induced strain was *** X-ray diffraction(XRD) results indicate the presence of a mixed phase of tetragonal and rhombohedral at the morphotropic phase boundary(MPB).Doping with an appropriate amount of Eu^(3+) reduces the Fe^(3+) content and decreases the leakage current in the binary system.A converse piezoelectric coefficient(d_(33)*) of 392 pm/v is obtained at BF-BT-0.003Eu under an electric field of 60 kv/cm at room temperature,which has a Curie temperature(T_(C)) of 414℃,The unipolar strain and d_(33)* of BF-BT-0.003Eu ceramics increase to 0.438%and 730 pm/v at 125℃ The field-induced strain response of the BF-BT-0.003Eu ceramics is greater than that of 0.67BF-0.33BT,mainly due to its optimal grain size,reduction of leakage current,and coexistence of ferroelectric-relaxation phases,BF-BT-0.003Eu ceramic is a lead-free candidate for high-temperature actuator applications.

关键词： Ferroelectric Field-induced strain Ceramics Lead-free Rare earths

CCD/EMCCD光电参数测试系统的设计与应用

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中国光学（中英文） 2024年第3期17卷 693-703页

作者：沈吉 vIACHESLAv v.Zabudsky 常维静那启跃简云飞 oleg v.Rikhalsky OLEKSANDR G.Golenkov vOLODYMYR P.Reva 华东光电集成器件研究所江苏苏州215263 乌克兰科学院v.E.Lashkaryov半导体物理研究所乌克兰基辅01001 乌克兰科学院Bogomoletz生理学研究所乌克兰基辅01001

本文开发了一种用于测量CCD和EMCCD(电子倍增CCD)芯片光电参数的测试系统。该测试系统通过自动模式或手动模式间的切换,测量器件的暗电流、读出放大器的响应度、电荷转移效率、电荷容量和其他参数。该测试系统可以针对不同规格和结构的C... 详细信息

本文开发了一种用于测量CCD和EMCCD(电子倍增CCD)芯片光电参数的测试系统。该测试系统通过自动模式或手动模式间的切换,测量器件的暗电流、读出放大器的响应度、电荷转移效率、电荷容量和其他参数。该测试系统可以针对不同规格和结构的CCD/EMCCD器件,实现CCD晶圆或封装好的成品的参数测试,实现576×288、640×512、768×576、1024×1024、1280×1024 CCD/EMCCD的测试和筛选。

关键词： CCD EMCCD 测试系统光电参数

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Recent theoretical progress in the development of perovskite photovoltaic materials

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Journal of Energy Chemistry 2018年第3期27卷 637-649页

作者： Xin Zhou Joanna Jankowska Hao Dong oleg v.Prezhdo College of Environment and Chemical Engineering Dalian University.Dalian 116622.LiaoningChina Department of Chemistry University of Southern CaliforniaLos Angeles 90089California.United States Institute of Physics.Polish Academy of Sciences Warsaw 02-668.Poland School of Chemistry and Chemical Engineering Liaoning Normal UniversityDalian 116029LiaoningChina

Since the seminal work by Kojima et al. in 2009, solar cells based on hybrid organic-inorganic perovskites have attracted considerable attention and experienced an exponential growth, with photovoltaic efficiencies as of today reaching above 22%. Despite such an impressive development, some key scientific issues of these materials, including the presence of toxic lead, the poor long-term device stability under heat and humidity conditions, and the anomalous hysteresis of the current-voltage curves shown by various solar cell devices, still remain unsolved and constitute an important focus of experimental and theoretical researchers throughout the world. Density functional theory calculations have been successfully applied to exploring structural and electronic properties of semiconductors, complementing the experimental results in search and discovery of novel functional materials. In this review, we summarize the current progress in perovskite photovoltaic materials from a theoretical perspective. We discuss design of lead-free perovskite materials, humidity-induced degradation mechanisms and possible origins for the observed solar cell hysteresis, and assess future research directions for advanced perovskite solar cells based on computational materials design and theoretical understanding of intrinsic properties.

关键词： Solar cells Perovskite materials Density functional theory

Chemical passivation of methylammonium fragments eliminates traps,extends charge lifetimes,and restores structural stability of CH_(3)NH_(3)PbI_(3) perovskite

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Nano Research 2022年第5期15卷 4765-4772页

作者： Xi Zhao Wei-Hai Fang Run Long oleg v.Prezhdo College of Chemistry Key Laboratory of Theoretical&Computational Photochemistry of Ministry of EducationBeijing Normal UniversityBeijing 100875China Department of Chemistry University of Southern CaliforniaLos AngelesCalifornia 90089USA

Hybrid organic-inorganic perovskites are currently considered the most promising next-generation photovoltaic ***,poor stability,arising from structural degradation under exposure to moisture,heat,and strong current,remains a critical challenge for their device *** ab initio nonadiabatic molecular dynamics,we demonstrate that methylamine fragments deriving from the dissociation of the methylammonium cation can undermine structural stability,produce deep hole traps,and decrease charge carrier lifetimes by 1-3 orders of *** stability and charge lifetime can be restored by methylamine passivation with chlorines,which withdraw electrons from the lone electron pair of methylamine and bring the trap levels down into the valence *** charge lifetime of the passivated system is even longer than that of the pristine *** simulations reveal the detailed microscopic mechanism underlying deterioration of perovskite performance due to molecular defects,and demonstrate an effective defect passivation strategy to obtain highly efficient and stable perovskite solar cells.

关键词： hybrid organic-inorganic perovskites structural stability methylammonium dissociation chlorine passivation time-domain density functional theory nonadiabati cmolecular dynamics

Eye movement prediction by oculomotor plant Kalman filter with brainstem control

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控制理论与应用（英文版） 2009年第1期7卷 14-22页

作者： oleg v.KOMOGORTSEv Javed I.KHAN Department of Computer Science Texas State University-San Marcos Department of Computer Science Kent State University

Our work addresses one of the core issues related to Human Computer Interaction （HCI） systems that use eye gaze as an input. This issue is the sensor, transmission and other delays that exist in any eye tracker-based system, reducing its performance. A delay effect can be compensated by an accurate prediction of the eye movement trajectories. This paper introduces a mathematical model of the human eye that uses anatomical properties of the Human visual System to predict eye movement trajectories. The eye mathematical model is transformed into a Kalman filter form to provide continuous eye position signal prediction during all eye movement types. The model presented in this paper uses brainstem control properties employed during transitions between fast （saccade） and slow （fixations, pursuit） eye movements. Results presented in this paper indicate that the proposed eye model in a Kalman filter form improves the accuracy of eye movement prediction and is capable of a real-time performance. In addition to the HCI systems with the direct eye gaze input, the proposed eye model can be immediately applied for a bit-rate/computational reduction in real-time gaze-contingent systems

关键词： Eye movement prediction Bio engineering Human computer interaction

Dormant stages of crustaceans as a mechanism of propagation in the extreme and unpredictable environment in the Crimean hypersaline lakes

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Chinese Journal of Oceanology and Limnology 2015年第6期33卷 1362-1367页

作者： Nickolai v.SHADRIN Elena v.ANUFRIIEvA Francisco AMAT oleg Yu.EREMIN MLR Key Laboratory of Saline Lake Resources and Environments Institute of Mineral Resources Institute of Marine Biological Research of RAS Instituto de Acuicultura de Torre de la Sal (CSIC)

A pool of dormant stages of planktonic organisms in saline lakes is a substantial component in the plankton communities;we need to take it into account to understand plankton *** water bodies in Crimea,the largest peninsula in the Black Sea,constitute a very characteristic and peculiar habitat type in the *** examined the presence of crustacean resting stages in sediments of dried up sites of the Crimean hypersaline *** samples were taken in 9 different *** performed on the hatching of these resting stages showed the presence of Moina salina(Cladocera),parthenogenetic Artemia and Artemia urmiana(Anostraca),Eucypris mareotica( inflata)(Ostracoda),and Cletocamptus retrogressus(Harpacticoida).Comparing the experimental results obtained with clean dried brine shrimp cysts and those kept in sediment samples,it was noted that clean cysts hatched much faster than those from sediments *** components in bottom sediments slow down and desynchronize hatching from resting eggs in different groups of *** sediments of different lakes inhibited the nauplii output from Artemia and ostracod resting eggs to different *** data are needed before we can discuss the reasons of this *** nonsynchronous output of active stages from the bottom resting ones may be an adaptation that allows crustacean species to exist in extreme and unpredictably changing environments,avoiding the risk that all may emerge at once under unsuitable conditions.

关键词： resting stages hypersaline waters Crustacea Crimea sediment

Argo floats revealing bimodality of large-scale mid-depth circulation in the North Atlantic

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Acta Oceanologica Sinica 2008年第2期27卷 1-10页

作者： CHU Peter C IvANOv Leonid M MELNICHENKO oleg v LI Rongfeng Department of Oceanography Naval Postgraduate School Monterey California USA International Pacific Research Center University of Hawaii at Manoa Hawaii USA Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

Analysis of Argo float trajectories at 1 000 m and temperature at 950 m in the North Atlantic between November 2003 and January 2005 demonstrates the existence of two different circulation modes with fast transition between them. Each mode has a pair of cyclonic - anticyclonic gyres. The difference is the location of the cyclonic gyre. The cyclonic gyre stretches from southeast to northwest in the first mode and from the southwest to the northeast in the second mode. The observed modes strongly affect the heat and salt transport in the North Atlantic. In particular, the second mode slows down the westward transport of the warm and saline water from the Mediterranean Sea.

关键词： Argo trajectory data Atlantic Ocean biomodality mid-depth circulation optimal spectral decomposition

Numerical 3D-modeling of spall and shear fractures in shells of austenitic 12Kh18N10T steel and 30KhGSA steel under their spherical and quasi-spherical explosive loading

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International Journal of Modeling, Simulation, and Scientific Computing 2015年第1期6卷 173-211页

作者： Evgeny A.Kozlov oleg v.Ol’khov Ekaterina v.Shuvalova Russian Federal Nuclear Center–Zababakhin Research Institute of Technical Physics Snezhinsk Russia Russian Federal Nuclear Center–Research Institute of Experimental Physics Sarov Russia

To pursue vNIIEF–vNIITF joint investigations,this paper briefly describes the experimental setup and provides numerical 3D-computation results(LEGAK-3D technique)on special features in the convergence dynamics of steel shells under their quasi-spherical explosive loading in the system with the 40-mm outer radius of the explosive *** computation results were compared with the data experimentally registered for shells of the 30KhGSA steel,both as-received and quenched to HRC 35...40,and the austenitic 12Kh18N10T stainless *** comparison was also made with laserinterferometry results obtained directly under explosive loading,as well as with gammatomography and scanning electron microscopy investigations of the recovered shells.

关键词： Convergence dynamics of shell spall and shear damages explosive loading

Efficient passivation of DY center in CH_(3)NH_(3)PbBr_(3) by chlorine:Quantum molecular dynamics

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Nano Research 2022年第3期15卷 2112-2122页

作者： Ran Shi Wei-Hai Fang Andrey S.vasenko Run Long oleg v.Prezhdo College of Chemistry Key Laboratory of Theoretical&Computational Photochemistry of Ministry of EducationBeijing Normal UniversityBeijing 100875China National Research University Higher School of Economics(HSE)University 101000 MoscowRussia Donostia International Physics Center(DIPC) Paseo Manuel de Lardizabal 4San Sebastián/Donostia20018 Basque CountrySpain Department of Chemistry University of Southern CaliforniaLos AngelesCA 90089USA

MAPbBr_(3)(MA=CH_(3)NH_(3)^(+))doping with bismuth increases electric conductivity,charge carrier density and photostability,reduces toxicity,and expands light ***,Bi doping shortens excited-state lifetimes due to formation of DY−charge recombination *** nonadiabatic molecular dynamics and time-domain density functional theory,we demonstrate that the DY−center forms a deep,highly localized hole trap,which accelerates nonradiative relaxation ten-fold and is responsible for 90%of carrier *** trapping occurs by coupling between the valence band and the trap state,facilitated by the Br atoms surrounding the Bi *** of the DY−center with chlorines heals the local geometry distortion,eliminates the trap state,and makes the carrier lifetimes longer than even in pristine MAPbBr_(3).The decreased charge recombination arises from reduced nonadiabatic coupling and shortened coherence time,due to diminished electron–hole overlap around the passivated *** study demonstrates accelerated nonradiative recombination in Bi-doped MAPbBr_(3),suggests a strategy for defect passivation and reduction of nonradiative energy losses,and provides atomistic insights into unusual defect properties of metal halide perovskites needed for rational design of high-performance perovskite solar cells and optoelectronic devices.

关键词： Hybrid organic-inorganic perovskite DY−center and Cl passivation charge trapping and recombination nonadiabatic molecular dynamics time-domain density functional theory.