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Impact of lanthanum on the modification of HfO_2 films structure

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Journal of Rare Earths 2015年第8期33卷 857-862页

作者： T.P.Smirnova L.v.Yakovkina v.O.borisov Nikolaev Institute of Inorganic Chemistry SB RAS

LaxHf1-xOy thin films with various concentrations of La, homogeneous and nonhomogeneous distributions of elements throughout the films thickness was purposefully grown by CvD. The composition of the films and their chemical structures were characterized throughout the films thickness by X-ray photoelectron spectroscopy （XPS） and energy-dispersive X-ray spectrometry （EDXA）. A full picture of the film crystallinity was provided by the combination of grazing incidence X-ray diffraction （GIXRD） synchrotron radiation （SR） and high resolution transmission electron microscopy （HR TEM）. It was shown that La acted as ＂molar volume modulator＂ and stabilized the nonequilibrium at T≤1300 ℃ cubic phases. The samples with La content in range of 7 at.%〈CLa〈22 at.% were materials with fluorite-type （Fm-3m） structure. The pyroehlore phase formation was observed at -18 at.% La content. The correlation between the La-doped content and the films microstructure was revealed.

关键词： Hf1-xLaxOy films solid solutions X-ray diffraction microstructure rare earths

Physical vapor transport growth and morphology of Bi2Se3 microcrystals

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Particuology 2016年第3期14卷 118-122页

作者： v.v. Atuchin S.v. borisov T.A. Gavrilova K.A. Kokh N.v. Kuratieva N.v. Pervukhina Laboratory of Optical Materials and Structures Institute of Semiconductor Physics SB RAS Novosibirsk 630090 Russia Functional Electronics Laboratory Tomsk State University Tomsk 634050 Russia Laboratory of Semiconductor and Dielectric Materials Novosibirsk State University Novosibirsk 630090 Russia Laboratory of Crystul Chemistry Institute of Inorganic Chemistry SB RAS Novosibirsk 630090 Russia Laboratory of Nanodiagnostics and Nanolithography Institute of Semiconductor Physics SB RAS Novosibirsk 630090 Russia Laboratory of Crystal Growth Institute of Geology and Mineralogy SB RAS Novosibirsk 630090 Russia Geology and Mineralogy Department Novosibirsk State University Novosibirsk 630090 Russia Spintronics Laboratory Saint Petersburg State University Saint Petersburg 198504 Russia Laboratory of Research Methods of Composition and Structure of Functional Materials Novosibirsk State University Novosibirsk 630090 Russia

High-quality Bi2Se3 microcrystals were grown by the physical vapor transport （PvT） method without using a foreign transport agent. The microplate crystals grown under the optimal temperature gradient are well faceted and have dimensions up to -200 μm, The growth proceeds by the layer-by-layer mecha- nism with the formation of flat low-growth rate facets. The phase composition of the grown crystals was identified by the X-ray single crystal structure analysis in space group R3m, a = 4.1356（3）, C= 28.634（5）A, Z=3 （R=0.0147）. The most probable twin planes in the tetradymite structure were evaluated by the pseudo translational sublattice merhad.

关键词： Bi2Se3 Physical vapor transport Structure Twin

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

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

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

Photoluminescence properties of Eu3+-doped MgAl2O4 nanoparticles in various surrounding media

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Journal of Rare Earths 2019年第8期37卷 806-811,I0001页

作者： I.E.Kolesnikov E.v.Golyeva E.v.borisov E.Yu Kolesnikov E.Lahderanta A.v.Kurochkin M.D.Mikhailov St.Petersburg State University St.PetersburgRussia Lappeenranta University of Technology LUT LappeenrantaFinland Peter the Great St.Petersburg Polytechnic University St.PetersburgRussia Scientific and Technological Institute of Optical Material Science VNTs S.I.Vavilov State Optical InstituteSt.PetersburgRussia volga State University of Technology Yoshkar-OlaRussia

Eu3+-doped MgAl2O4 nanoparticles were prepared by modified Pechini method.X-ray diffraction analysis shows pure tetragonal spinel phase without any *** average size of synthesized nanoparticles was determined to be about 50-60 nm using scanning electron microscopy and static light scattering *** and excitation spectra as well as lifetimes of MgAl2O4:Eu3+ nanophosphors were explored in surrounding media with different refractive *** medium does not affect luminescence bands position,whereas 5D0 lifetime monotonically decreases along with increase of medium refractive *** of surrounding media on radiative and nonradiative decay rates,which were calculated using 4f-4f intensity theory,was studied and *** factor of prepared nanoparticles is defined using both radiative and observed lifetimes.

关键词： Eu3+ Nanoparticles Filling factor Luminescence Lifetime Rare earths