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304篇 您的检索式:作者名="KovalenkoE"
    题名 作者 年代 出处 被引量
1定向洛伦兹力对激光熔覆熔池排气的影响显示文摘采用稳态磁场和电场耦合形成定向洛伦兹力,基于多物理场耦合原理及网格变形法建立了定向洛伦兹力作用下的熔池模型,采用离散元法模拟了熔池内的气泡运动过程。与熔覆工艺条件相同但未施加外场时比较,结果显示,定向洛伦兹力具有优异的气孔调控能力。当洛伦兹力向上时,熔池的最高流速被抑制了62.5%,气泡运动方向向下偏转,熔覆层的气孔明显增多;当洛伦兹力向下时,熔池的最高流速被抑制了25%,但气泡因所受浮力增大而逸出加速,熔覆层无气孔。仿真结果与实验结果吻合良好,验证了仿真模型的可靠性。胡勇 王梁 李珏辉 张群莉 姚建华 Volodymyr Kovalenko 2018中国激光2018,45,8:14
2半导体直接输出激光加工系统开发与温度控制策略研究显示文摘针对大功率半导体直接输出激光加工系统的应用,本文搭建了由大功率半导体激光器、工控机、机械手运动系统、测温仪和WAGO通讯模块等组成的激光加工系统的硬件平台,提出了大功率半导体激光直接输出加工过程中激光加工温度的控制方法,设计了基于Lab Windows/CVI交互式软件开发环境的PID和模糊控制算法,并且通过现场实验对两种控制算法的各个参数进行了精确整定。整定后的PID和模糊的温度控制效果良好,PID控制的温度峰值时间只有0.45s,最大超调量为3.28%,稳态均方根误差为1.01℃;模糊控制的温度峰值时间为0.93s,最大超调量为1.5%,稳态均方根误差为2.22℃。为了对比两种控制策略的实际控制效果,以设定温度为1 250℃,启动功率为500 W,45#钢基体为实验条件,分别对整定后的PID控制和模糊控制以不同的扫描速度进行激光相变硬化实验,实验发现随着扫描速度的增加,PID控制与模糊控制的稳定性都有所降低,但是在相同扫描速度下,模糊控制的超调量较小,温度控制更稳定。因此模糊控制策略更适合于本控制系统,最终本系统采用模糊控制作为激光加工的温度控制策略。徐元飞 胡晓冬 姚建华 Volodymyr Kovalenko 2015应用激光2015,35,1:7
3液态二氧化碳对俄罗斯某油藏稠油的膨胀与萃取作用实验显示文摘利用俄罗斯某油藏稠油样品,通过实验分析稠油与液态CO_2混合后两者之间的质量传递作用以及混合物中重相(稠油和CO_2的混合物)和轻相(纯CO_2)的特性变化。研究表明,当混合物中CO_2浓度为10%时,稠油基本上不发生膨胀;当混合物中CO_2浓度高于26%时,由于稠油轻质组分的萃取量超过了CO_2在稠油中的饱和量导致重相体积减少,重相黏度呈指数增长,混合物中CO_2的浓度为26%时,有效降低重相黏度的作用最强;重相和轻相密度、体积系数、气体溶解度和闪蒸重相黏度均随着混合物中CO_2浓度的增加而变大;混合物中最佳的CO_2浓度是26%,此时稠油膨胀最大、重相的黏度值最小;混合物中CO_2的浓度为10%~26%时,轻相的体积最小,驱油效果最好。LOBANOV A A SHHEKOLDIN K A STRUCHKOV I A ZVONKOV M A HLAN M V PUSTOVA E J KOVALENKO V A ZOLOTUKHIN A B 2018石油勘探与开发2018,45,5:6
4超音速激光沉积Ti-6Al-4V合金结合界面特征数值模拟及试验验证显示文摘目的探究超音速激光沉积(SLD)过程中激光辐照温度和颗粒撞击速度对Ti-6Al-4V合金结合界面特征的影响规律,并通过试验对数值模拟结果进行验证。方法基于Johnson-cook材料模型,利用ABAQUS 2017软件并采用欧拉-拉格朗日耦合CEL(Coupled Euler-Lagrange)计算模型和Lagrange计算模型,进行Ti-6Al-4V单颗粒和多颗粒的撞击行为数值模拟,并结合超音速激光沉积试验验证模拟结果。采用扫描电镜(SEM)和光镜(OM)对涂层的界面结合特征进行观察和分析。结果单颗粒撞击温度场模拟结果表明,当激光辐照温度为1073 K时,随着撞击速度的增加,颗粒界面结合温度不断升高。当撞击速度为800 m/s和900 m/s时,颗粒与基体局部最高温度分别为1876.7 K和1874.8 K,界面发生微熔。800 m/s时,颗粒压缩率为34.3%,扁平率为1.27,有效塑性应变为2.6,基体的凹坑深度为7.88μm,该参数下的超音速激光沉积涂层界面结合良好。多颗粒撞击温度场模拟结果表明,当撞击速度为800 m/s时,随着激光辐照温度的升高,孔隙逐渐减少。激光辐照温度为1073 K时,颗粒撞击界面的温度高达3463.7 K,但颗粒内部的温度还未达到熔点并保留在1073~1676.8 K。随着激光功率的升高,钛合金涂层的孔隙率降低为0.67%(SLD 700W),约为同条件下CS涂层孔隙率(8.31%)的1/12。结论激光辐照的热能使颗粒与基体以及颗粒间界面处的温度达到了材料熔点,实现颗粒表面微熔形成冶金结合。冷喷涂Ti-6Al-4V涂层中,颗粒与基体以及颗粒间均存在明显的孔隙,超音速激光沉积Ti-6Al-4V涂层颗粒与基体以及颗粒间的界面结合良好,试验结果与数值模拟结果大致吻合。汪伟林 吴丽娟 李波 Volodymyr Kovalenko 张群莉 姚建华 2020表面技术2020,49,8:5
5硅酸盐-盐(硫酸盐)流体不混溶:蒙古南部Mushugai-Khuduk含火成碳酸岩杂岩体矿物中的熔体包裹体研究显示文摘Crystalline and melt inclusions were studied in garnet,diopside,potassium feldspar,and sphene from the garnet syenite porphyry of the carbonatite-bearing complex Mushugai-Khuduk,southern Mongolia.Phlogopite,clinopyroxene,albite,potassium feldspar,spheric,wollastonite,magnetite,Ca and Sr sulfates,fluorite,and apatite were identified among the crystalline inclusions. The melt inclusions were homogenized at 1010~1080℃and analyzed on an electron microprobe.Silicate,salt,and combined silicate- salt melt inclusions were found.Silicate melts show considerable variations in SiO_2 concentration(56 to 66wt% ),high Na_2O+K_2O (up to 17wt% ),and elevated Zr,F,and C1 contents.In terms of bulk rock chemistry,the silicate melts are alkali syenites.During thermometric experiments,salt melt inclusions quenched into homogeneous glasses of predominantly sulfate compositions containing no more than 1.3wt% SiO_2.These melts are enriched in alkalis,Ba,Sr,P,F,and C1.The investigation of the silicate and salt melt inclusions in minerals of the garnet syenite porphyries indicate that these rocks were formed under influence of the processes of crystallization differentiation and magma separation into immiscible silicate and salt(sulfate)liquids.Irina A. Andreeva Vyacheslav I. Kovalenko Vladimir B. Naumov 2007岩石学报2007,23,1:5
6基于改进BP神经网络算法的激光相变硬化层深度的研究显示文摘采用实验与神经网络预测相结合的方法,对基于温度控制的激光相变硬化工艺参数进行了研究。首先,使用基于温度可控的大功率半导体直接输出激光加工系统对45~#钢进行设定温度下的激光相变硬化实验。然后,通过改进的BP神经网络算法构建神经网络模型,并采用所获得的实验样本数据训练该人工神经网络模型。模型中所采用的改进BP神经网络算法是遗传算法和基于新型误差函数的批量训练神经网络算法相结合的混合算法。为验证改进算法的性能,在Lab Windows/CVI软件上应用C编程语言实现了该算法。通过运行程序发现,采用此算法的收敛速度比传统算法提高了约80%,预测输出的指标与实际值之间的偏差小于4%。易金鑫 胡晓冬 姚建华 黄利安 Kovalenko Volodymyr 2017应用激光2017,37,1:5
7Synthesis of cyclic carbonates from epoxides or olefins and CO_2 catalyzed by metal-organic frameworks and quaternary ammonium salts显示文摘Catalytic properties of the metal-organic framework Cr-MIL-101 in solvent-free cycloaddition of CO2to epoxides to produce cyclic carbonates using tetrabutylammonium bromide as co-catalyst have been explored under mild reaction conditions (8 bar CO2, 25C). Styrene and propylene carbonates were formed with high yields (95% and 82%, respectively). Catalytic performance of Cr-MIL-101 was compared with other MOFs: Fe-MIL-101, Zn-MOF-5 and HKUST-1. The catalytic properties of different quaternary ammonium bromides, Cr-MIL-101 as well as PW 12 /Cr-MIL-101 composite material have been assessed in oxidative carboxylation of styrene in the presence of both tert-butyl hydroperoxide and H2O2 as oxidants at 8 100 bar CO2and 25 80C with selectivity to styrene carbonate up to 44% at 57% substrate conversion.Olga V. Zalomaeva Nataliya V. Maksimchuk Andrey M. Chibiryaev Konstantin A. Kovalenko Vladimir P. Fedin Bair S. Balzhinimaev 2013Journal of Energy Chemistry2013,22,1:5
8Frequency-multiplexed entanglement for continuous-variable quantum key distribution显示文摘Quantum key distribution with continuous variables already uses advantageous high-speed single-mode homodyne detection with low electronic noise at room temperature.Together with continuous-variable information encoding to nonclassical states,the distance for secure key transmission through lossy channels can approach 300 km in current optical fibers.Such protocols tolerate higher channel noise and also limited data processing efficiency compared to coherent-state protocols.The secret key rate can be further increased by increasing the system clock rates,and,further,by a suitable frequency-mode-multiplexing of optical transmission channels.However,the multiplexed modes couple together in the source or any other part of the protocol.Therefore,multiplexed communication will experience cross talk and the gain can be minuscule.Advantageously,homodyne detectors allow solving this cross-talk problem by proper data processing.It is a potential advantage over protocols with single-photon detectors,which do not enable similar data processing techniques.We demonstrate the positive outcome of this methodology on the experimentally characterized frequency-multiplexed entangled source of femtosecond optical pulses with natural cross talk between eight entangled pairs of modes.As the main result,we predict the almost 15-fold higher secret key rate.This experimental test and analysis of frequencymultiplexed entanglement source open the way for the field implementation of high-capacity quantum key distribution with continuous variables.OLENA KOVALENKO YOUNG-SIK RA YIN CAI VLADYSLAV C.USENKO CLAUDE FABRE NICOLAS TREPS RADIM FILIP 2021Photonics Research2021,9,12:3
9铺粉厚度对选区激光熔化316L沉积层致密度与表面形貌的影响显示文摘目的 为了解决选区激光熔化增材再制造时出现的首层铺粉粉层厚度不均的问题,研究首层粉层厚度为400μm时选区激光熔化成形工艺。方法 采用倾斜基板预置楔形粉层,在粉层上进行不同激光功率的激光扫描实验,研究楔形粉层对沉积的影响规律。然后在水平放置的基板上分别预置50、100、200、300、400μm厚度粉层,在粉层上进行激光扫描实验,研究粉层厚度对沉积的影响规律。最后做首层400μm层厚,后续5层每层50μm的多层沉积实验,研究厚粉层对后续SLM成形的影响规律。结果 在倾斜上表面采用选区激光熔化技术进行修复,铺粉厚度的增加会导致沉积层致密度变差且表面起伏增大。通过提高激光能量密度的方式,采用300 W、800 mm/s的工艺参数在400μm大层厚下激光扫描,可改善沉积层与基板的结合情况并减小沉积层上表面的起伏轮廓,同时该参数也能在小层厚时得到致密的沉积层。在首层400μm层厚的基础上进行SLM成形时,需用首层沉积的工艺沉积5层作为过渡区,后续可按正常的SLM成形工艺进行沉积。结论 用SLM技术进行零件修复时,虽然首层会出现厚度不均的楔形粉层。当粉层最厚区域不超过400μm时,需提高激光功率密度进行沉积。在高功率密度参数下沉积5层后可以采用正常SLM工艺进行后续成形。张杰 杨高林 徐侠 姚建华 Volodymyr Kovalenko 2022表面技术2022,51,3:2
10热障涂层后处理技术研究进展显示文摘热障涂层是一种降低航空发动机热端部件表面温度、提高发动机推力和效率的热防护技术,但其服役于高温、高压、高交变应力等恶劣环境而易脱落失效.对热障涂层的后处理技术进行了阐述,论述了真空热处理、热等静压处理、激光重熔、激光上釉、激光熔覆等后处理技术的方法和原理,并对比了不同工艺的优缺点.最后,展望了激光表面改性技术的应用前景和未来发展趋势.李灿锋 张盼盼 姚建华 张群莉 Volodymyr Kovalenko 2022材料研究与应用2022,16,1:2
11MAP3K-related kinase involved in NF-kappaB induction by TNF,CD95 and IL-1显示文摘Malinin NL Bldin MP Kovalenko AV 1997Nature1997,385,:1
12Problems in treating in-fluenza and acute respiratory infection in children 显示文摘Romantsov MG Ershov FI Kovalenko AL 2011Eksp KlinFarmakol2011,74,6:1
13Electro- chemical modification of lignins 显示文摘Kovalenko E l Popova O V Aleksandrov A A 2000Russian Journal of Electro- chemistry2000,36,7:1
14Expression of MMP-9 in mesangial cells and its changes in anti-GBM glomerulonephritis in WKY rats显示文摘Kuroda T Yoshida Y Kamiie J Kovalenko P Nameta M Fujinaka H Yaoita E Endo T Ishizuka S Nakabayashi K Yamada A Nagasawa T Yamamoto T 2004Clin Exp Nephrol2004,8,:1
15Endometrial pathomorphology in bacterial vaginosis associated with chronic endo- metritis显示文摘Kovalenko VL Voropaeva EE Kozachkov EL 2008Arkh Patol2008,70,:1
16Dynamics of Gas Release from a Coal Seam in Driving a Working显示文摘Yu. F. Kovalenko V. I. Karev 2001Journal of Mining Science2001,,1:1
17A major constituent of brown algae for use in high-capacity Li-ion batteries显示文摘Kovalenko I 2011Science2011,334,:1
18Evidence for extrapla- eental sources of circulating angiogenic growth effeetors in human pregnancy 显示文摘Zamudio S Kovalenko O Ecbalar L 2013Placenta2013,34,12:1
19Changingthepathogeneticroadmapofliverfibrosis?Wherediditstart;wherewillitgo?显示文摘GressnerOA RizkMS KovalenkoE etal 2008JGastroenterolHepatol2008,23,71:1
20Prospects of colloidal nanocrystals for electronic and op- toelectronicapplications显示文摘Dmitri V Talapin Jong-Soo Lee Maksym V Kovalenko 2010Chem Rev2010,110,:1
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