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Highly transparent ytterbium doped yttrium lanthanum oxide ceramics

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Journal of Rare Earths 2014年第3期32卷 254-258页

作者： m.Ivanov Yu.Kopylov V.kravchenko 李江 A.medvedev 潘裕柏 Institute of Electrophysics UrB of RAS 106Amundsena 620016 Ekaterinburg Russia Institute of Radioengineering and Electronics named after V.A. Kotelnikov RAS Vvedensky Sq. 1 Fryazino Moscow region 141120 Russia Shanghai Institute of Ceramics Chinese Academy of Science Ural Federal University 19 Mira 620002 Ekaterinburg Russia

To prepare ytterbium doped lanthania yttria nanopowder a method of laser evaporation of mixed oxides was used. After calcinations of the powder at 1200 ℃ a pure single-phase solid solution yb3＋：（LaxY1-x）2O3 was formed in the nanoparticles. Influence of lanthanum oxide as an isovalent additive on the yttria structure was investigated. The lanthanium ions were proved to be a good aid to sinter yttria ceramics doped with Yb3＋ at moderate temperatures about 1650 ℃. The ceramics with relative density higher than 99.99% and grain size about 40 μm were fabricated. Full transmittance of 1.8 mm thick Yb0.11 La0.23Y1.66O3 ceramics reached 82.5% at 800 nm. This material could be a good gain medium for ytterbium high power pulse lasers.

关键词： RE-doped ceramics nanopowders ytterbium oxide transparency

mollisols Properties and Changes in Ukraine and China

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Chinese Geographical Science 2011年第3期21卷 257-266页

作者： Yuri S kravchenko ZHANG Xingyi LIU Xiaobing SONG Chunyu Richard m CRUSE Key Laboratory of mollisols Agroecology Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Harbin 150081 China National University of Life and Environmental Sciences of Ukraine Kyiv 03041 Ukraine Department of Agronomy Iowa State University Ames 500011 IA USA

Soils are the foundation of civilizations and the basis for human food *** in Ukraine and Northeast China are two out of the four major mollisol regions in the *** natural areas from which mollisols developed are the prairies and steppes that experience temperate and freezing *** review paper introduces the general climate,vegetation,and topography of mollisols regions in Ukraine and Northeast China,analyzes their properties,including soil texture,soil organic matter content,soil bulk density,pH,cation exchange capacity and other chemical properties,and compares the property changes and management practices of mollisols in relation to sustainable grain production.

关键词： mollisols soil properties soil organic matter tillage mollisols management

multiband emission from single β-NaYF_(4)(Yb,Er) nanoparticles at high excitation power densities and comparison to ensemble studies

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Nano Research 2021年第11期14卷 4107-4115页

作者： Florian Frenzel Christian Würth oleksii Dukhno Frédéric Przybilla Lisa mWiesholler Verena muhr Thomas Hirsch Yves mély Ute Resch-Genger Federal Institute for materials Research and Testing(BAm) Division 1.2 BiophotonicsRichard-Willstaetter-Str.1112489BerlinGermany Laboratory of Biomaging and Pathologies UMR 7021 CNRSUniversity of Strasbourg67000StrasbourgFrance Institute of Analytical Chemistry Chemo-and BiosensorsUniversity of Regensburg93040RegensburgGermany Institut für Physik and IRIS Adlershof Humboldt-Universität zu BerlinNewtonstraße 1512489BerlinGermany

Ensemble and single particle studies of the excitation power density (P)-dependent upconversion luminescence (UCL) of core and core-shell β-NaYF_(4):Yb,Er upconversion nanoparticles (UCNPs) doped with 20% Yb^(3+) and 1% or 3% Er^(^(3+)) performed over a P regime of 6 orders of magnitude reveal an increasing contribution of the emission from high energy Er^(3+) levels at P > 1 kW/cm^(2). This changes the overall emission color from initially green over yellow to white. While initially the green and with increasing P the red emission dominate in ensemble measurements at P m^(2), the increasing population of higher Er^(^(3+)) energy levels by multiphotonic processes at higher P in single particle studies results in a multitude of emission bands in the ultraviolet/visible/near infrared (UV/vis/NIR) accompanied by a decreased contribution of the red luminescence. Based upon a thorough analysis of the P-dependence of UCL, the emission bands activated at high P were grouped and assigned to 2–3, 3–4, and 4 photonic processes involving energy transfer (ET), excited-state absorption (ESA), cross-relaxation (CR), back energy transfer (BET), and non-radiative relaxation processes (nRP). This underlines the P-tunability of UCNP brightness and color and highlights the potential of P-dependent measurements for mechanistic studies required to manifest the population pathways of the different Er^(3+) levels.

关键词： upconversion luminescence single nanoparticle study high power excitation emission color luminescence decay kinetics

Growth of skyrmionic mnSi nanowires on Si： Critical importance of the SiO2 layer

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Nano Research 2014年第12期7卷 1788-1796页

作者： Siwei Tang Ivan kravchenko Jieyu Yi Guixin cao Jane Howe David mandrus Zheng Gai Department of materials Science and Engineering University of Tennessee Knoxville TN 37996 USA Center for Nanophase materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA Hitachi High Technologies Inc. Rexdale ON M9W 6A4 Canada

mnSi in the B20 structure is a prototypical helimagnet that forms a skyrmion lattice, a vortex-like spin texture under applied magnetic field. We have systematically explored the synthesis of single crystal mnSi nanowires via controlled oxide-assisted chemical vapor deposition and observed a characteristic signature of skyrmion magnetic ordering in the mnSi nanowires. The thickness of the SiO2 layer on the Si substrate plays the key role in obtaining a high yield of B20 mnSi skyrmion nanowires. A growth mechanism was proposed that is consistent with the existence of an optimum SiO2 thickness. A growth phase diagram was constructed based on the extensive studies of various growth conditions for various mnSi nanostructures. The persistence of both the helicoidal and skyrmion magnetic ordering in the one-dimensional wires was directly revealed by ac and dc magnetic measurements.

关键词： skyrmion spintronics oxide-assisted growth nanowires magnetic materials

Rapid prototyping of a polymer mEmS dropletdispenser by laser-assisted 3D printing

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microsystems & Nanoengineering 2023年第4期9卷 211-221页

作者： Rémi Courson oleksii Bratash Ali maziz CloéDesmet Ricardo Alvarado meza Loïc Leroy Elodie Engel Arnaud Buhot Laurent malaquin Thierry Leïchlé LAAS-CNRS Universitéde ToulouseCNRS31400 ToulouseFrance UniversitéGrenoble Alpes CNRSCEAIRIGSyMMES38000 GrenobleFrance Georgia Tech−CNRS International Research Laboratory AtlantaGA 30332USA

In this work, we introduce a polymer version of a previously developed silicon mEmS drop deposition tool for surfacefunctionalization that consists of a microcantilever integrating an open fluidic channel and a reservoir. The device isfabricated by laser stereolithography, which offers the advantages of low-cost and fast prototyping. Additionally,thanks to the ability to process multiple materials, a magnetic base is incorporated into the cantilever for convenienthandling and attachment to the holder of a robotized stage used for spotting. Droplets with diameters ranging from∼50 μm to ∼300 μm are printed upon direct contact of the cantilever tip with the surface to pattern. Liquid loading isachieved by fully immersing the cantilever into a reservoir drop, where a single load results in the deposition of morethan 200 droplets. The influences of the size and shape of the cantilever tip and the reservoir on the printing outcomeare studied. As a proof-of-concept of the biofunctionalization capability of this 3D printed droplet dispenser,microarrays of oligonucleotides and antibodies displaying high specificity and no cross-contamination are fabricated,and droplets are deposited at the tip of an optical fiber bundle.

关键词： cantilever reservoir printing

Switching O-O bond formation mechanism between WNA and I2m pathways by modifying the Ru-bda backbone ligands of water-oxidation catalysts

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Journal of Energy Chemistry 2021年第3期30卷 815-821页

作者： Biaobiao Zhang Shaoqi Zhan Tianqi Liu Linqin Wang A.Ken Inge Lele Duan Brian J.J.Timmer Oleksandr kravchenko Fei Li marten S.G.Ahlquist Licheng Sun Department of Chemistry KTH Royal Institute of Technology10044 StockholmSweden Department of Theoretical Chemistry&Biology School of Engineering Sciences in Chemistry Biotechnology and HealthKTH Royal Institute of Technology10691 StockholmSweden Department of materials and Environmental Chemistry Stockholm University10691 StockholmSweden Department of Chemistry Southern University of Science and Technology(SUSTech)Shenzhen 518055GuangdongChina State Key Laboratory of Fine Chemicals Institute of Artificial PhotosynthesisDUT–KTH Joint Education and Research Center on Molecular DevicesDalian University of Technology(DUT)Dalian 116024LiaoningChina

Understanding the seven coordination and O-O coupling pathway of the distinguished Ru-bda catalysts is essential for the development of next generation efficient water-oxidation catalysts based on earthabundant *** work reports the synthesis,characterization and catalytic properties of a monomeric ruthenium catalyst Ru-bnda(H2 bnda=2,2’-bi(nicotinic acid)-6,6’-dicarboxylic acid)featuring steric hindrance and enhanced hydrophilicity on the *** experimental evidence with systematic density functional theory calculations on the Ru-bnda and related catalysts Ru-bda(H_(2)bda=2,2’-bipyridine-6,6’-dicarboxylic acid),Ru-pda(H_(2)pda=1,10-phenanthroline-2,9-dicarboxylic acid),and Ru-biqa(H_(2)biqa=(1,1’-biisoquinoline)-3,3’-dicarboxylic acid),we emphasized that seven coordination clearly determines presence of Ru^(Ⅴ)=O with high spin density on the ORu^(Ⅴ)=O atom,*** with radical properties,which is one of the necessary conditions for reacting through the O-O coupling ***,an additional factor to make the condition sufficient is the favorable intermolecular faceto-face interaction for the generation of the pre-reactive[Ru^(Ⅴ)=O…O=Ru^(Ⅴ)],which may be significantly influenced by the secondary coordination *** work provides a new understanding of the structure-activity relationship of water-oxidation catalysts and their potential to adopt I2m pathway for O-O bond formation.

关键词： Water oxidation Oxygen evolution Ruthenium O-O bond formation

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深海蓝绿--绿色公寓

室内设计与装修 2017年第4期 30-35页

作者： oleksii Venediktov Antonina Venediktova 文同

绿色公寓（GREENAPARTmENT）是PECIALPROJECTVENEDIKTOV在2016年最新完成的一座公寓，项目位于乌克兰基辅一栋高层建筑的30楼，可以俯瞰城市的美景，也可以欣赏到第聂伯河的壮丽与优雅。公寓面积约为160m2。一对年轻的夫妇买下了这套公... 详细信息

绿色公寓（GREENAPARTmENT）是PECIALPROJECTVENEDIKTOV在2016年最新完成的一座公寓，项目位于乌克兰基辅一栋高层建筑的30楼，可以俯瞰城市的美景，也可以欣赏到第聂伯河的壮丽与优雅。公寓面积约为160m2。一对年轻的夫妇买下了这套公寓，希望设计师可以根据需求，创建一个以极简的斯堪的纳维亚风格为基调的住宅，并通过个性化的装饰让生活空间变得令人印象深刻。

关键词：公寓深海斯堪的纳维亚高层建筑生活空间乌克兰设计师个性化

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典型黑土区村级尺度侵蚀沟演变

中国水土保持科学 2012年第2期10卷 21-28页

作者：李浩张兴义刘爽 Yury kravchenko Kateryna Ivanova 李续峰陈强中国科学院东北地理与农业生态研究所哈尔滨150081 中国科学院研究生院北京100049 乌克兰国立生命与环境科学大学基辅乌克兰03041

侵蚀沟的演变是东北水土流失过程的重要方面。利用1968和2009年亚米级遥感影像,获取典型黑土区村级尺度的侵蚀沟分布、耕地垄向和土地利用数据,基于1∶1万地形图获取等高线、坡度、坡长和垄向坡度数据,在地理信息系统和遥感技术的支持下... 详细信息

侵蚀沟的演变是东北水土流失过程的重要方面。利用1968和2009年亚米级遥感影像,获取典型黑土区村级尺度的侵蚀沟分布、耕地垄向和土地利用数据,基于1∶1万地形图获取等高线、坡度、坡长和垄向坡度数据,在地理信息系统和遥感技术的支持下,分析典型黑土区41 a村级尺度侵蚀沟的动态变化及其影响因素。结果表明:1)41 a间,典型黑土区侵蚀沟密度有明显增加的趋势,基于分辨率为亚米级遥感影像解译的侵蚀沟密度较以往研究结果大幅增加;2)自然坡度0.25°～1.5°范围内为该区域侵蚀沟密度变化最大的区域,8°以上区域由于实施退耕还林措施,侵蚀沟密度降低;3)300～500 m坡长区域侵蚀沟密度出现极值;4)由于实施改垄措施,41 a后垄向坡度在0～0.25°范围内耕地面积增加,大于0.25°范围内耕地面积均减少。

关键词：侵蚀沟密度演变黑土区

一种新型简易心脏mRI评分系统（PE2RT）预测Takotsubo综合征预后

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国际医学放射学杂志 2023年第5期 625-625页

作者： A.Isaak J.Bratz D.kravchenko N.mesropyan I.Eckardt L.m.Bischof 许振华

摘要目的探索与Takotsubo综合征（TTS）主要不良心血管事件（mACE）相关的简易心脏mRI(CmR)影像特征。方法回顾性分析2007—2021年期间行CmR检查的TTS病

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