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Runaway electrons during subnanosecond breakdowns in high-pressure gases

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High Voltage 2016年第4期1卷 181-191页

作者： victor f.tarasen.o Mikhail I.Lomaev Dmitry V.Beloplotov Dmitry A.Sorokin Institute of High Current Electronics Siberian Branch Russian Academy of Science2/3 Akademicheskii Ave.Tomsk 634055Russia

The parameters of runaway electrons produced in nanosecond high-voltage discharges in different gases(air,nitrogen,sulphur hexafluoride,krypton,argon,methane,neon,hydrogen,helium)at atmospheric and higher pressure were *** optical analysis was also performed to investigate the ionisation dynamics in diffuse discharges in nitrogen and nitrogen-containing *** breakdown of a point-to-plane gap by nanosecond(≃2 ns)high-voltage(≃200 kV)pulses of negative voltage polarity and gas pressure above 0.1 MPa,a supershort avalanche electron beam(SAEB)was detected by a collector behind the flat *** pressure>0.1 MPa of nitrogen and other gases it is shown that the maximum pressure for SAEB registration decreases with increasing the voltage pulse rise ***,to detect a SAEB at atmospheric and higher gas pressure,one should use voltage pulses with an amplitude of hundred kilovolts and rise time of∼1 ns and *** experimental research in the dynamics of optical radiation from the discharge plasma shows that the breakdown in which runaway electrons are produced develops as an ionisation wave.

关键词： wave. gases fluoride

Galvanic and asymmetry effects on the local electrochemical behavior of the 2098-T351 alloy welded by friction stir welding

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Journal of Materials Science & Technology 2020年第10期42卷 162-175页

作者： Mariana X.Milagre Uyime Donatus Naga V.Mogili Rejane Maria PSilva Barbara victoria Gde Viveiros victor f.Pereira Renato A.Antunes Caruline S.CMachado Joao victor S.Araujo Isolda Costa Instituto de Pesquisas Energeticas e Nucleares IPEN/CNENAv.Prof.Lineu Prestes2242Sao PauloBrazil Laboratorio Nacional de Nanotecnologia LNNano/CNPENRua Giuseppe Maximo Scolfaro10.000Polo II deAlta Tecnologia de CampinasBrazil Centro de Engenharia Modelagem e Ciencias Sociais AplicadasUFABCAv.dos Estados 5001Santo AndreBrazil

Scanning electrochemical microscopy(SECM)and scanning vibrating electrode technique(SVET)were used to investigate the electrochemical behaviour of the top surface of the 2098-T351 alloy welded by friction stir welding(fSW).The SVET technique was efficient in identifying the cathodic and anodic weld *** welding joint(WJ),which comprises the thermomechanically affected zone(TMAZ)and the stir zone(SZ),was cathodic relative to the heated affected zone(HAZ)and the base metal(BM).The reactivities of the welding joint at the advancing side(AS)and the retreating side(RS)were analyzed and compared using SECM technique in the competition mode by monitoring the dissolved oxygen as a redox mediator in 0.005 mol L^-1 NaCl *** RS was more electrochemically active than the AS,and these results were correlated with the microstructural features of the welded alloy.

关键词： Aluminum alloys friction stir welding Localized corrosion

Novel virtual nasal endoscopy system based on computed tomography scans

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Virtual Reality & Intelligent Hardware 2022年第4期4卷 359-379页

作者： fábio de o.SoUSA Daniel S.da SILVA Tarique da S.CAVALCANTE Edson C.NETo victor JoséT.GoNDIM Ingrid C.NoGUEIRA Auzuir Ripardo de ALEXANDRIA victor Hugo C.de ALBUQUERQUE federal Institute of Ceará-IfCE Telecommunication Engineering ProgramBrazil Graduate Program on Teleinformatics Engineering Federal University of CearáFortaleza/CEBrazil Centro Universitário Christus-UniChristus Brazil Centro Universitário Sete de Setembro-Uni7 Brazil

Background Currently,many simulator systems for medical procedures are under *** systems can provide new solutions for training,planning,and testing medical practices,improve performance,and optimize the time of the ***,to achieve the best results,certain premises must be followed and applied to the model under development,such as usability,control,graphics realism,and interactive and dynamic *** This study presents a system for simulating a medical examination procedure in the nasal cavity for training and research purposes,using a patient′s accurate computed tomography(CT)as a *** pathologies that are used as a guide for the development of the system are ***,an overview of current studies covering bench medical mannequins,3D printing,animals,hardware,software,and software that use hardware to boost user interaction,is ***,a comparison with similar state-of-the-art studies is *** The main result of this work is interactive gamification techniques to propose an experience of simulation of an immersive exam by identifying pathologies present in the nasal cavity such as hypertrophy of turbinates,septal deviation adenoid hypertrophy,nasal polyposis,and tumor.

关键词： Virtual nasal endoscopy Computed tomography Gamification Endoscopy teaching

on periodic groups with prescribed orders of elements

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Science China Mathematics 2009年第2期52卷 311-317页

作者： MAZURoV victor Danilovich Sobolev Institute of Mathematics Siberian Branch of Russian Academy of Sciences

This is a survey of results and open problems concerning the structure of periodic group with prescribed orders of their elements. In particular, an outline of a proof of the following recent result is given: every pe... 详细信息

关键词： spectrum periodic group local finiteness 20f50

Hypolipidemic and Antioxidative Effects of African Star Apple Juice (Chrysophylum albidum) on Rats fed on Diets High in Cholesterol and oil

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food and Nutrition Sciences 2016年第10期7卷 825-843页

作者： Modupe f. Bobadoye oluwaseun o. Bamisi victor N. Enujiugha Department of food Science and Technology Federal University of Technology Akure Nigeria

This study investigated the possible hypolipidemic and antioxidative effects of Chrysophylum albidum juice in rats fed on highcholesterol and fatty diets (HfCD). The juice was expressed, pasteurized and frozen until needed. Diets were formulated by mixing at different ratios. Bio-assay of the blends was carried out for a period of 28 days. Twenty five male rats were divided into five groups of five each: a normal diet group, a high-cholesterol diet group, a high fat/Cholesterol diet with 3 ml of African Star Apple Juice group, a high fat/Cholesterol diet with 6 ml of African Star Apple Juice group, and a high fat/Cholesterol diet with 9 ml of African Star Apple Juice group. Blood serum, selected tissues and organs were collected and the serum lipid profile, organ histology and oxidative stress test were carried out at the end of the animal experimentation. The levels of total cholesterol, triglyceride, low density lipoprotein-cholesterol, very low density lipoprotein-cholesterol and artherogenic index obtained from rats treated with African star apple juice (3 ml, 6 ml and 9 ml) decreased significantly (P ≤ 0.05), compared respectively to the HfCD rats. The results also showed that treatment with African star apple (Chrysophylum albidum) positively changed plasma antioxidant enzyme activities and lipid profiles in cholesterol-fed rats, and thus may have potential hypolipidemic and antioxidant effects, and by inference, the antiatherogenic properties in male rats. African star apple (Chrysophylum albidum) juice could protect against oxidative stress linked atherosclerosis and decrease the atherogenic index, thereby supporting the local use of Chrysophylum albidum in the management of atherosclerosis and hypertensive conditions.

关键词： Chrysophyllum albidum Atherosclerosis Antioxidant Activity Hypolipidemic Effects oxidative Stress

The Cretaceous Turn of Geological Evolution: Key Evidence from East Asia

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Acta Geologica Sinica(English Edition) 2018年第5期92卷 1991-2003页

作者： victor P.NECHAEV DAI Shifeng f.Lin SUTHERLAND Ian T.GRAHAM Eugenia V.NECHAEVA far East Geological Institute Far Eastern Branch Russian Academy of Sciences Engineering School Far Eastern Federal University State Key Laboratory of Coal Resources and Safe Mining China University of Mining and Technology School of Resources and Geosciences China University of Mining and Technology Geoscience Australian Museum PANGEA Research Centre School of Biological Earth and Environmental Sciences University of New South Wales

this work focuses on one of the critical points of Earth＇s history when the Solar System passed through the most distant point of its galactic orbit. During this event, Earth may have suffered from maximum extension, associated with its relative proximity to the Sun at that time, followed by long-term contraction related to its later distancing. This paper is based on generalized data on the Cretaceous evolution of the Earth as a whole and of East Asia in particular. The evidence suggests that major geological processes at this time may be interpreted as transitional changes in the state of Earth. A liquid nature of its core may have reacted to the gravitational and electromagnetic transformations. When the cosmic changes took place at 135-120 Ma, more turbulent flows in the outer core would have favoured the rise of voluminous magmatic plumes and associated fluid flows. These would substantially transform the mantle, crust, hydrosphere, biosphere and atmosphere. In particular, plume-related melting of overlying subducting slabs and lower continental crust could have initiated numerous adakitic melts that formed the East Asian Adakitic Province. These and associated juvenile events produced numerous metallic ore, coal, gas and oil deposits. The Cretaceous is one of the most significant resource-producing periods.

关键词： Cretaceous geological evolution galactic orbit super plume adakitic rocks coal ore and petroleum resources

大气压空气纳秒脉冲板-板放电中逃逸电子产生机理

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物理学报 2023年第10期72卷 233-241页

作者：肖江平戴栋 victor f.tarasen.o 邵涛华南理工大学电力学院广州510641 俄罗斯科学院大电流研究所俄罗斯托木斯克634055 中国科学院电工研究所北京100190

经典放电理论(Townsend和流注理论)解释纳秒脉冲气体放电存在局限性,近年来基于高能电子逃逸的纳秒脉冲气体放电理论研究受到广泛关注.但是目前对大气压空气纳秒脉冲板-板放电中逃逸电子产生机理研究仍较少,严重阻碍了纳秒脉冲放电等离... 详细信息

经典放电理论(Townsend和流注理论)解释纳秒脉冲气体放电存在局限性,近年来基于高能电子逃逸的纳秒脉冲气体放电理论研究受到广泛关注.但是目前对大气压空气纳秒脉冲板-板放电中逃逸电子产生机理研究仍较少,严重阻碍了纳秒脉冲放电等离子体的应用发展.本文利用一维粒子模型,对幅值为20 kV的纳秒脉冲电压驱动下,间隙长为1 mm的板-板电极之间的大气压空气放电中逃逸电子的产生机理进行了数值模拟研究..结果表明,在空间电荷动力学行为的影响下,板-板电极之间出现了增强电场区域,使得电子可以满足电子逃逸判据而进入逃逸模式.此外,还观察到放电通道前逃逸电子的预电离效应导致了二次电子崩的产生,随着二次电子崩与放电通道不断汇聚,引导并加速了放电通道的发展,最终导致气隙击穿.本研究进一步揭示了纳秒脉冲板-板放电机理,拓展了纳秒脉冲气体放电基础理论,为纳秒脉冲放电等离子体的应用和发展开辟了新的机会.

关键词：纳秒脉冲放电逃逸电子增强电场预电离

Implicit large eddy simulation of unsteady cloud cavitation around a plane-convex hydrofoil

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Journal of Hydrodynamics 2015年第6期27卷 815-823页

作者： HIDALGo victor 罗先武 ESCALER Xavier 季斌 AGUINAGA Alvaro Beijing Key Laboratory of Co2 Utilization and Reduction Technology Tsinghua University CDIf Universitat Politècnica de Catalunya School of Power and Mechanical Engineering Wuhan University Mechanical Engineering Department Escuela Politecnica Nacional University

The present paper focuses on the erosive cavitation behavior around a plane convex hydrofoil. The Zwart-Gerber-Belamri cavitation model is implemented in a library form to be used with the openfoAM. The implicit large eddy simulation （ILES） is app- lied to analyze the three-dimensional unsteady cavitating flow around a plane convex hydrofoil. The numerical results in the cases under the hydrodynamic conditions, which were experimentally tested at the high speed cavitation tunnel of the l^cole Polytechnique f6d＆ale de Lausanne （EPfL）, clearly show the sheet cavitation development, the shedding and the collapse of vapor clouds. It is noted that the cavitation evolutions including the maximum vapor length, the detachment and the oscillation frequency, are captured fairly well. furthermore, the pressure pulses due to the cavitation development as well as the complex vortex structures are reasona- bly well predicted. Consequently, it may be concluded that the present numerical method can be used to investigate the unsteady cavitation around hydrofoils with a satisfactory accuracy.

关键词： implicit large eddy simulation (ILES) unsteady partial cavitation Zwart-Gerber-Belamri cavitation model openfoAM,Q - criterion

Impacts of degrading permafrost on streamflow in the source area of Yellow River on the Qinghai-Tibet Plateau,China

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Advances in Climate Change Research 2019年第4期10卷 225-239页

作者： MA Qiang JIN Hui-Jun victor f.BENSE LUo Dong-Liang Sergey S.MARCHENKo Stuart A.HARRIS LAN Yong-Chao State Key Laboratory of frozen Soils Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou730000China College of Resources and Environment University of Chinese Academy of SciencesBeijing100049China School of Civil Engineering Harbin Institute of TechnologyHarbin150090China Hydrology and Quantitative Water Management Group Department of Environmental SciencesWageningen UniversityWageningen6708PBthe Netherlands Geophysical Institute(GIPL) University of Alaska FairbanksFairbanks99775USA Department of Geography University of CalgaryCalgaryT3A 1E4Canada

Many observations in and model simulations for northern basins have confirmed an increased streamflow from degrading permafrost,while the streamflow has declined in the source area of the Yellow River(SAYR,above the Tanag hydrological station)on the northeastern Qinghai-Tibet Plateau,West *** and to what extent does the degrading permafrost change the flow in the SAYR?According to seasonal regimes of hydrological processes,the SAYR is divided intofour sub-basins with varied permafrost extents to detect impacts of permafrost degradation on the Yellow River *** show that permafrost degradation may have released appreciable meltwater for recharging *** potential release rate of ground-ice melt-water in the Sub-basin 1(the headwater area of the Yellow River(HAYR),above the Huangheyan hydrological station)is the highest(5.6 mm per year),contributing to 14.4%of the annual Yellow River streamflow at ***/intra-and annual shifts of streamflow,a possible signal for the marked alteration of hydrological processes by permafrost degradation,is observed in the HAYR,but the shifts are minor in other sub-basins in the *** hydraulic connectivity is expected to occur during and after certain degrees of permafrost *** impacts of permafrost degradation on the annual Yellow River streamflow in the SAYR at Tanag,i.e.,from the meltwater of ground-ice,is estimated at 4.9%that of the annual Yellow River discharge at Tanag,yet with a high uncertainty,due to neglecting of the improved hydraulic connections from permafrost degradation and the flow generation conditions for the ground-ice *** evapotranspiration,substantial weakening of the Southwest China Autumn Rain,and anthropogenic disturbances may largely account for the declined streamflow in the SAYR.

关键词： Streamflow Warming climate Permafrost degradation Streamflow patterns Source area of Yellow River(SAYR)