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Plasma Science and Technology 2017年第3期19卷 93-97页

作者： a f popovich V G RALCHENKO V K BALLA A K MALLIK A A KHOMICH A P BOLSHAKOV D N SOVYK E E ASHKINAZI V Yu YUROV Institute of Radio Engineering and Electronics of Russian Academy of Sciences Fryazino 141190 Russia General Physics Institute of Russian Academy of Sciences Moscow 119991 Russia Harbin Institute of Technology Harbin 150001 People's Republic of China National Research Nuclear University MEPhI Moscow 115409 Russia Central Glass and Ceramic Research Institute Kolkata 700 032 India

Polycrystalline diamond（PCD） films 100 mm in diameter are grown by 915 MHz microwave plasma chemical vapor deposition（MPCVD） at different process parameters,and their thermal conductivity（TC） is evaluated by a laser flash technique（LfT） in the temperature range of230-380 *** phase purity and quality of the films are assessed by micro-Raman spectroscopy based on the diamond Raman peak width and the amorphous carbon（a-C） presence in the *** and increasing dependencies for TC with temperature are found for high and low quality samples,***,as high as 1950 ± 230 W m-1 K-1 at room temperature,is measured for the most perfect material.A linear correlation between the TC at room temperature and the fraction of the diamond component in the Raman spectrum for the films is established.

关键词： thermal conductivity polycrystalline diamond microwave plasma chemical vapordeposition Raman spectroscopy

Kinetics and Structure of Refractory Compounds and Alloys Obtained by Mechanical Alloying

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Journal of Materials Science & Technology 2001年第1期17卷 63-64页

作者： A.A.popovich V.P.Reva T.A.popovich O.V Arestov far Eastern State Technical University 10 Pushkin Street 690600 VladivostokRussia

Refractory compounds are material with interesting properties for structural applications. However, the processing of Such material is a great challenge because of their high melting temperature and limited ductility. Mechanical alloying is a novel technique of producing refractory compounds with specific properties. Kinetical and structural peculiarities of refractory compounds and alloys obtained by mechanical alloying are discussed.

关键词： mechanical alloying specific properties melting temperature great challenge

Mossbauer Study of Mechanica Aloying fe-Ti and fe-Ti-N Alloys

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Journal of Materials Science & Technology 2001年第1期17卷 1-2页

作者： T.A.popovich O.V.Arestov A.A.popovich A.S.Kuchma far Eastern State Technical University 10 Pushkin St.

Mossbauer spectrometry was used to study the peculiarity of formation of nonequilibrium phase in fe-Ti and fe-Ti-N systems by mechanical alloying. Mossbauer spectra of powders show the formation of nonequilibrium crystalline phase and intermetallic compounds during a mechanical alloying process depending on the alloy composition and the milling time.

关键词： Ti fe ssbauer Study of Mechanical Alloying fe-Ti and fe-Ti-N Alloys

Corrosion and passive film characteristics of 3D-printed NiTi shape memory alloys in artificial saliva

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Rare Metals 2023年第9期42卷 3114-3129页

作者： Ming Liu Jia-Ning Zhu V.A.popovich E.Borisov J.M.C.Mol Y.Gonzalez-Garcia State Key Laboratory for Mechanical Behavior of Materials Center for Advancing Materials Performance from the Nanoscale(CAMP-Nano)Xi’an Jiaotong UniversityXi’an710049China Department of Materials Science and Engineering Delft University of TechnologyAA Delft2600The Netherlands Peter the Great Saint-Petersburg Polytechnic University Saint Petersburg195251Russia

Electrochemical tests and surface analysis were applied to study the corrosion behavior and passive film characteristics of three-dimensional-printed NiTi shape memory alloys fabricated by laser-powder bed fusion(LPBf) in artificial saliva at 37.C. The passivity of L-PBf NiTi shows to be influenced by the process parameters and resulting morphological and physicochemical surface properties. The results show that the defects at the surface of L-PBf Ni Ti can promote the passivation rate in the early stages of exposure but a slowly formed passive film shows the best corrosion protection. The thickness of the passive film is positively correlated with its corrosion protective performance. The L-PBf NiTi alloy prepared at a linear energy density of 0.2 J·m^(-1) and volumetric energy density of 56 J·mm^(-3) shows the least defects and best corrosion protection. An outer Ti-rich and inner Ni-rich dense passive film could be also obtained showing higher corrosion resistance.

关键词： NiTi Laser-powder bed fusion(L-PBf) Passive film Corrosion resistance Artificial saliva

Enrichment of the less polar ginsenoside (Rg3) from ginseng grown in New Zealand by post-harvest processing and extraction

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Traditional Medicine Research 2021年第4期6卷 136-149页

作者： Wei Chen Wen-Liang Xu Dan-Xia Shi Prabhu Balan David popovich School of food and Advanced Technology Massey UniversityPalmerston North 4442New Zealand Riddet Institute Massey UniversityPalmerston North 4442New Zealand

Background:Previous studies showed that New Zealand-grown ginseng contains an abundance of ginsenosides and that rare less polar ginsenosides,such as Rg3,exhibit more pharmacological activities than polar ginsenosides,which are the major components of ***:The ginsenoside profile of New Zealand-grown Panax ginseng was manipulated by treatment with acetic acid,sodium hydroxide,pH,and high *** abundance of 23 ginsenosides extracted by different treatments was quantified using high-performance liquid ***:Treatment with 0.5 mol/L acetic acid can stimulate the degradation of polar ginsenosides to less polar ginsenosides(5.6%Rg3 was accumulated,Pfurthermore,when ginseng root was treated at 121℃ for 100 min in a pH 3.0 acetic acid aqueous solution,the majority of the polar ginsenosides were converted into less polar ***,83.46±3.69%(P=0.0360)of the less polar ginsenosides and 41.01±2.39%(P=0.0412)of Rg3 were *** contrast,alkali treatment did not convert the polar ginsenosides into less polar ginsenosides at mild temperature and less conversion was observed compared with acid treatment at high ***:This is the first attempt to manipulate the ginsenoside profile of New Zealand-grown *** conditions(high temperature with low pH)may be modified to produce and enrich the less polar ginsenoside fraction(especially Rg3)from the total ginseng extract.

关键词： New Zealand grown ginseng Less polar ginsenoside Ginsenoside Rg3 Ginsenoside transformation

Mechanochemical method for producing iron-based nitrogen-containing nanocrystalline alloys

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广东有色金属学报 2005年第2期15卷 255-257页

作者： Anatoly A.popovich Pavel A. Nikiforov Vera A.popovich far-Eastern State Technical University Vladivostok Russia

Iron-based products account the main volume of powder metallurgy production. Nevertheless its strength and reliability are not enough in comparison with classical cast materials. So that is why making nanostructural powder materials allows to increase strength and extend the range of products. A principally new way of nanostructure production is possible by means of iron mechanical alloying with nitride-forming and nitrogen both at the same time. Unlike classical technology of internal nitrogenation, nitrogen saturation, in our case, occurs by whole volume at plastic deformation conditions. A review of experimental results of phase forming alloys in the fe-Ni, fe-Ni-Cr, fe-Ni-N, fe-Ni-Cr-N, fe-Cr-Ni systems prepared by mechanical alloying are given. The influence of the technological parameters of mechanical alloying, atmosphere of mechanical activation on nitrogen content and phase composition of examined alloys has been studied. Experimental results of the influence of mechanical alloying technological parameters on degree of ammonia dissociation and nitrogen content in examined alloys are presented. Heat treatment influence of mechanically alloyed, nitrogen-containing alloys on their phase composition and structure are investigated. It was shown that using mechanical alloying, it’s possible to prepare high-alloyed iron-based alloys containing more than 1% of nitrogen. It was established that technology of mechanical alloying in ammonia atmosphere allows to prepare austenitic steels with nanocrystalline structure, which affords high value of yield stress. Physico-chemical patterns of interaction between the nitrogen-containing atmosphere and nitride-forming elements under their mutual mechanical activation conditions were established in consequence of theoretical and experimental researches. Some scientific principles of nanocrystalline materials were gained by quantitative description of correlation between the mechanical dose, nitrogen potential, nitrogen conten

关键词：纳米晶体合金机械化学铁氮冶炼方法

山楂黄酮提取物的抗氧化活性和对癌细胞生长抑制作用

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食品科学 2010年第3期31卷 220-223页

作者：柳嘉 David Glen popovich 景浩中国农业大学食品科学与营养工程学院北京100083 新加坡国立大学化学系新加坡肯特岗117543

目的:研究山楂(Crataegus pinnatifida Bunge)黄酮提取物的抗氧化能力以及对人肝癌Hep-G2细胞和人肠癌Caco-2细胞生长抑制作用。方法:比较测定总黄酮含量的直接法和两种铝盐显色法,进一步采用硝酸铝盐显色法测定提取物总黄酮含量,ABTS法... 详细信息

目的:研究山楂(Crataegus pinnatifida Bunge)黄酮提取物的抗氧化能力以及对人肝癌Hep-G2细胞和人肠癌Caco-2细胞生长抑制作用。方法:比较测定总黄酮含量的直接法和两种铝盐显色法,进一步采用硝酸铝盐显色法测定提取物总黄酮含量,ABTS法和DPPH法分析提取物的抗氧化活性,MTT法评价山楂黄酮提取物对细胞生长的抑制效果。结果:山楂黄酮提取物中黄酮含量占干质量的98%,清除ABTS和DPPH自由基的能力随提取物剂量的增加而升高,EC50分别为88μg/mL和112μg/mL,而标准品Trolox的EC50清除ABTS和DPPH自由基的能力分别为111μg/mL和118μg/mL。山楂黄酮提取物能够有效地抑制癌细胞的生长,且对Hep-G2细胞的抑制效果更强,Hep-G2细胞和Caco-2细胞的IC50分别约为115μg/mL和376μg/mL。结论:山楂黄酮提取物黄酮含量高,抗氧化能力强,有抑制癌细胞的作用,是一种有效的天然抗氧化剂。

关键词：山楂黄酮提取物抗氧化 Hep-G2细胞 Caco-2细胞生长抑制

笃斯越橘花青素提取物对3T3-L1前脂肪细胞生长的抑制作用

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食品科学 2010年第15期31卷 248-252页

作者：柳嘉 David G.popovich 景浩中国农业大学食品科学与营养工程学院北京100083 新加坡国立大学化学系新加坡117543

目的:研究笃斯越橘花青素提取物对3T3-L1前脂肪细胞生长抑制作用及其作用机理。方法:采用MTT法观察细胞生长抑制并确定半数抑制浓度(IC50),LDH(lactate dehydrogenase)法评价提取物引起的细胞膜损伤,流式细胞计法测定细胞周期,荧光显微... 详细信息

目的:研究笃斯越橘花青素提取物对3T3-L1前脂肪细胞生长抑制作用及其作用机理。方法:采用MTT法观察细胞生长抑制并确定半数抑制浓度(IC50),LDH(lactate dehydrogenase)法评价提取物引起的细胞膜损伤,流式细胞计法测定细胞周期,荧光显微镜观察凋亡细胞的形态学特征。结果:笃斯越橘花青素提取物能够有效地抑制3T3-L1前脂肪细胞的生长且IC50约为214μg/mL;LDH实验表明细胞LDH释放率在24、48、72h分别为89.0%、85.2%、67.8%,72h时相对24h或48h明显降低(P<0.05),提取物对3T3-L1前脂肪细胞膜的通透性未见明显增加;笃斯越橘花青素提取物能够有效诱导细胞凋亡,同时在S或G0/G1期产生阻滞,但是对细胞的G2/M期未见明显影响,荧光显微镜观察细胞出现典型凋亡特征。结论:笃斯越橘花青素提取物能有效抑制3T3-L1前脂肪细胞生长的作用,具有开发为天然抗肥胖功能因子的潜在可能。

关键词：笃斯越橘花青素提取物 3T3-L1前脂肪细胞生长抑制细胞凋亡

Confidence Intervals for Assessing Sizes of Social Network Centralities

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Social Networking 2018年第4期7卷 220-242页

作者： Dawn Iacobucci Rebecca McBride Deidre L. popovich Maria Rouziou Vanderbilt University Nashville TN USA finance and Administration Development Deloitte New York NY USA Texas Tech University Lubbock TX USA

This research uses random networks as benchmarks for inferential tests of network structures. Specifically, we develop formulas for expected values and confidence intervals for four frequently employed social network centrality indices. The first study begins with analyses of stylized networks, which are then perturbed with increasing levels of random noise. When the indices achieve their values for fully random networks, the indices reveal systematic relationships that generalize across network forms. The second study then delves into the relationships between numbers of actors in a network and the density of a network for each of the centrality indices. In doing so, expected values are easily calculated, which in turn enable chi-square tests of network structure. furthermore, confidence intervals are developed to facilitate a network analyst’s understanding as to which patterns in the data are merely random, versus which are structurally significantly distinct.

关键词： Centrality Degree Closeness Betweenness Eigenvector Centrality Social Networks

60 GHz SIW Steerable Antenna Array in LTCC

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ZTE Communications 2012年第4期10卷 29-32页

作者： Bahram Sanadgol Sybille Holzwarth Peter Uhlig Alberto Milano Rafi popovich IMST GmbH Carl-friedrich-Gauss-Str. 2 47475 Kamp-Lintfort Germany Beam Networks 1 Ehad Ha'am 76248 RehovotIsrael

In this paper, we present a 60 GHz substrate-integrated waveguide fed-steerable low-temperature cofired ceramics array. The antenna is suitable for transmitting and receiving on the 60 GHz wireless personal area network frequency band. The wireless system can be used for HDTV, high-data-rate networking up to 4.5 GBit/s, security and surveillance, and similar applications.

关键词： substrate integrated waveguide(SIW) phase shifted injected push-push oscillator(PSIPPO) low temperature co-fired ceramic(LTCC) ~monolithic microwave integrated chip(MMIC) wireless personal area network(WPAN)