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Magnetic phase transition and continuous spin switching in a high-entropy orthoferrite single crystal

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Frontiers of physics 2024年第2期19卷 157-167页

作者： Wanting Yang Shuang Zhu Xiong Luo Xiaoxuan Ma Chenfei Shi Huan Song Zhiqiang Sun Yefei Guo yuriy Dedkov Baojuan Kang Jin-Ke Bao Shixun Cao Department of Physics Shanghai UniversityShanghai 200444China Materials Genome Institute and International Center for Quantum and Molecular Structures Shanghai UniversityShanghai 200444China School of Physics Southeast UniversityNanjing 211189China Shanghai Key Laboratory of High Temperature Superconductors Shanghai UniversityShanghai 200444China

Rare-earth orthoferrite REFeO_(3)(where RE is a rare-earth ion)is gaining *** created a high-entropy orthoferrite(Tm_(0.2)Nd_(0.2)Dy_(0.2)Y_(0.2)Yb_(0.2))FeO_(3)(HEOR)by doping five RE ions in equimolar ratios and grew the single crystal by optical floating zone *** strongly tends to form a single-phase structure stabilized by high configurational *** the low-temperature region(11.6‒14.4 K),the spin reorientation transition(SRT)ofΓ_(2)(F_(x),C_(y),G_(z))‒Γ_(24)‒Γ_(4)(G_(x),A_(y),F_(z))*** weak ferromagnetic(FM)moment,which comes from the Fe sublattices distortion,rotates from the a-to *** two-step dynamic processes(Γ_(2)‒Γ_(24)‒Γ_(4))are identified by AC susceptibility *** in HEOR can be tuned in the range of 50‒60000 Oe,which is an order of magnitude larger than that of orthoferrites in the peer system,making it a candidate for high-field spin *** spin-switching(SSW)and continuous spin-switching(CSSW)effects occur under low magnetic fields due to the strong interactions between RE‒Fe *** CSSW effect is tunable between 20‒50 Oe,and hence,HEOR potentially can be applied to spin modulation ***,because of the strong anisotropy of magnetic entropy change()and refrigeration capacity(RC)based on its high configurational entropy,HEOR is expected to provide a novel approach for refrigeration by altering the orientations of the crystallographic axes(anisotropic configurational entropy).

关键词： high-entropy oxide rare-earth orthoferrite spin reorientation transition spin switching magnetocaloric effect

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统计预测中的鲁棒性

国外科技新书评介 2014年第9期 4-4页

作者： yuriy kharin 张志斌不详中国科学院计算技术研究所

统计预测在包括工程、经济、金融、医药、环境等很多应用领域有着广泛的应用。对于多数的统计方法来说，评价效果的标准一般是基于预测与真实结果之间的平方差。因此在研究一种新的统计预测方法时往往是基于最小化平方差来进行设计。然... 详细信息

统计预测在包括工程、经济、金融、医药、环境等很多应用领域有着广泛的应用。对于多数的统计方法来说，评价效果的标准一般是基于预测与真实结果之间的平方差。因此在研究一种新的统计预测方法时往往是基于最小化平方差来进行设计。然而，在现实中的真实数据往往会偏离我们的理论假设。比如观测误差有可能不是高斯分布，数据中可能包含着异常值或者有缺失等等。

关键词：统计预测方法鲁棒性统计方法高斯分布观测误差平方差最小化异常值

基于平均方法的三体绳系系统末端星体姿态控制

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宇航学报 2024年第8期45卷 1261-1268页

作者：张莹王长青 ZABOLOTNOV yuriy ISHKOV Sergei 高辛西北工业大学自动化学院西安710129 萨马拉国家研究型大学萨马拉443086 航天推进技术研究院西安710100

针对三体绳系卫星系统展开过程星体姿态稳定问题,提出了动力学分析解与控制器设计相结合的控制策略。通过对三体绳系卫星系统中子星姿态振动的动力学方程应用平均方法,获得末端星体姿态振动的解析解,为控制器设计奠定了基础。基于化简... 详细信息

针对三体绳系卫星系统展开过程星体姿态稳定问题,提出了动力学分析解与控制器设计相结合的控制策略。通过对三体绳系卫星系统中子星姿态振动的动力学方程应用平均方法,获得末端星体姿态振动的解析解,为控制器设计奠定了基础。基于化简后的动力学方程设计了一种滑模控制律来抑制子星姿态振动,并利用李雅普诺夫理论证明了闭环系统的渐近稳定性。通过仿真实验验证了所提出方法的可行性和有效性,仿真结果不仅证明了理论分析解的准确性,还验证了控制器的有效性。

关键词：绳系卫星系统卫星姿态平均方法滑模控制

Trilayer anisotropic structure versus randomly oriented structure in heart valve leaflet tissue engineering

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Bio-Design and Manufacturing 2023年第4期6卷 423-438页

作者： yuriy Snyder Soumen Jana Department of Bioengineering University of MissouriColumbiaMO 65211USA

It has been hypothesized that leaflet substrates with a trilayer structure and anisotropicmechanical properties could be useful for the production of functional and long-lasting tissue-engineered *** investigate the influence of the anisotropic structural and mechanical characteristics of a substrate on cells,in this study,we electrospun trilayer anisotropic fibrous substrates and randomly oriented isotropic fibrous substrates(used as controls)from polycaprolactone ***,the random substrates had higher radial and lower circumferential tensile properties than the trilayer substrates;however,they had similar flexural *** valvular interstitial cells cultured on both substrates produced random and trilayer cell-cultured constructs,*** trilayer cell-cultured constructs had more anisotropic mechanical properties,17%higher cellular proliferation,14%more extracellular matrix(i.e.,collagen and glycosaminoglycan)production,and superior gene and protein expression,suggesting that more cells were in a growth state in the trilayer constructs than in the random ***,the random and radial layers of the trilayer constructs had more vimentin,collagen,transforming growth factor-beta 1(TGF-ß1),transforming growth factor-beta 3(TGF-ß3)gene expression than in the circumferential layer of the *** study verifies that the differences in structural,tensile,and anisotropic properties of the trilayer and random substrates influence the characteristics of the cells and ECM in the constructs.

关键词： Heart valve leaflet Trilayer Tissue engineering Fiber Electrospinning

Geothermal Model of the Fore-Yenisey Sedimentary Basin——Transitional Structure between the Ancient Siberian Platform and the Young West Siberian Plate

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Acta Geologica Sinica(English Edition) 2022年第2期96卷 582-590页

作者： Dmitriy NOVIKOV Fedor DULTSEV yuriy FILIPPOV Trofimuk Institute of Petroleum Geology and Geophysics SB RASNovosibirsk 630090Russia Novosibirsk State University Novosibirsk 630090Russia

Results of the investigation into the geothermal regime of the Fore-Yenisey sedimentary basin, formed during the collision and subsidence of the Kas-Turukhan microcontinent and the western margin of the Siberian craton in the late Neoproterozoic and early Paleozoic are reported. It was established that the structural and geothermal conditions of the upper Precambrian–Paleozoic sections are similar to those in the western regions of the Siberian platform and are characterized by rather low geothermal gradients(12.5–25.5 ℃/km). In the western parts of the basin, formation temperatures in the uppermost pre-Jurassic sediments are 50℃–85℃, decreasing eastward to 30℃–55℃. For the first time, the detailed geothermal model of the basin sedimentary fill was developed. This model allows predictions of the geothermal conditions of Earth’s interior.

关键词： geothermal model formation temperature Fore-Yenisey sedimentary basin West Siberia

Optical absorption and photoelectron collection properties of silicon wafers with conical quantum nanocrystals structure

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Nano-Micro Letters 2010年第3期2卷 149-153页

作者： yuriy Vashpanov Jae-Il Jeong Electrical and Computer Engineering Division of Hanyang Institute of Technology Hanyang University

A conical form of nano-sized quantum cluster was formed on the surface of p-type crystalline silicon [111] wafer by anode electrochemical etching in HF-based *** conical surface is highly effective in absorbing sunlight and transporting photoelectrons to semiconductor *** are because each cone has a graded band gap with the energy level in the range from 1.1 to 3 eV which can be considered as consisting of quantum dots in different *** the boron concentration on the surface of each cone gradually decreases from top to bottom,a continuously varying electrical field is created along the cone *** electric field is forcing photoelectrons generated in the cone to move rapidly to the direction perpendicular to wafer *** the drift time of photoelectrons can be less than their recombination time within the thin layer close to the bottom of the cone.

关键词： Silicon Nanocrystals Electrochemical etching Solar cells

Influence of polyolefin fibers on the strength and deformability properties of road pavement concrete

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Journal of Traffic and Transportation Engineering(English Edition) 2019年第4期6卷 407-417页

作者： Olga Smirnova Alexey Kharitonov yuriy Belentsov Department of Constructing Mining Enterprises and Underground Structures Saint-Petersburg Mining UniversitySaint Petersburg 199106Russia Department of Technology of Building Materials and Metrology Saint-Petersburg State University of Architecture and Civil EngineeringSaint Petersburg 190005Russia Department of Building Materials and Technologies Emperor Alexander I St.Petersburg State Transport UniversitySaint Petersburg 190031Russia

Influence of the type and quantity of polyolefin fibers on the strength properties(compression strength, tensile strength in bending, strength in uniaxial tension), the deformation properties(elastic modulus, Poisson’s coefficient) and the abrasion resistance of cement concrete with water-to-cement ratio within 0.31 e0.55 were stated in the *** ways of fibers introduction into fresh concrete were investigated. It was shown that the fibers introduction method and procedure of mixing are the ways to improve the fibers uniform distribution in fresh concrete. The increase of the bending tensile strength and the uniaxial tensile strength of concrete with fibers reinforcement in comparison with the reference concrete was observed with the water-to-cement ratio decrease. The increase of uniaxial tensile strength at age of 28 days for concrete with macrofibers in amount of4.5 kg/m^3 was 23% and 29%;for macrofibers in quantity of 3 kg/m^3 was 19% and 26% with water-cement ratio equal to 0.49 and 0.31, respectively. The maximum reduction of abrasion in the range of 7.5%e10% was observed in concrete with water-to-cement ratio within0.44 e0.55 for all investigated types of fibers. The influence of fibers on the concrete abrasion with lower W/C ratio was negligible. The results can contribute to the rational use of modified polyolefin fibers in road pavement concrete.

关键词： Road pavement concrete Polyolefin fibers Strength Elastic modulus Abrasion Water-to-cement ratio

Ectomycorrhiza of Larix sibirica Ledeb. along the gradients of main ecological factors and elevation at the Northern and Subpolar Urals

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Journal of Mountain Science 2018年第12期15卷 2603-2613页

作者： SIZONENKO Tatyana Alexandrovna DUBROVSKIY yuriy Alexandrovich Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Sciences Russia SyktyvkarKommunistieheskaya str28Syktyvkar167000Russian Federation

Siberian larch(Larix sibirica Ledeb.) forests cover the largest areas in the Eurasian boreal zone, but there are insufficient data on its root system including the structure and functional traits of ectomycorrhizas(EM). The aim of this research is to find out if the morphological parameters of Larix sibirica EMs responded to the changes in elevation and main ecological factors(soil humidity, soil richness, soil acidity and habitat illumination). Using light microscopy, we studied EM diameter, root diameter, mantle width, and mantle volume share, share of tannin cells layers, EM density and EM length of Larix sibirica in two main types of plant communities along the elevation gradient at the Northern and Subpolar Urals. Differences in the environment were traced using phytoindication approach and the Ellenberg ecological scales. All the studied traits depend on the elevation and studied ecological factors. The diversity of fungal mantles is low, and the proportion of unstructured and pseudoparenchymatous mantles is high in response to the deterioration of the humidity, soil nitrogen content and acidity at higher-altitude habitats. Results of EM quantitative parameters measurements confirmed this pattern. We found a decline in the EM linear dimensions accompanied by a compensatory growth of the EM density with the raised elevation and the deterioration of environmental conditions.

关键词： Ectomycorrhiza Larix sibirica Anatomy Fungal mantles diversity Elevation Urals

Thermal Stresses and Theorem on Decomposition

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Transactions of Nanjing University of Aeronautics and Astronautics 2014年第2期31卷 175-179页

作者： Valeriy Lokhov yuriy Nyashin Department of Theoretical Mechanics and Biomechanics Perm National Research Polytechnic University

The thermal expansion strain is considered as a special case of *** authors proved the theorem on decomposition of eigenstrain existing in a body into two constituents:Impotent eigenstrain(not causing stress in any point of a body)and nilpotent eigenstrain(not causing strain in any point of a body).According to this theorem,the thermal stress can be easily found through the nilpotent *** the eigenstrain is an impotent one,the thermal stress *** this case,the eigenstrain must be *** authors suggest a new approach to measure of eigenstrain incompatibility and hence to estimate of thermal stresses.

关键词： eigenstrain thermal stresses decomposition impotent eigenstrain nilpotent eigenstrain functional space