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Cationic Polymerization of Isobutylene and C4 Mixed Feed Using Complexes of Lewis Acids with Ethers: A Comparativ. Study

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Chinese Journal of Polymer Science 2019年第9期37卷 891-897页

作者： Dmitriy I. Shiman Iv.n A. Berezianko Irina v. v.silenko Sergei v. Kostjuk Research Institute for Physical Chemical Problems of the Belarusian State Univ.rsity 14 Leningrads kaya St. Minsk 220006 Belarus Department of Chemistry Belarusian State University 14 Leningradskaya st. Minsk 220006 Belarus Sechenov.First Moscow State Medical Univ.rsity Institute for Regenerative Medicine 8-2 Trubetskaya st. Moscow 119991 Russia

The cationic polymerization of C4 mixed feed and isobutylene co-initiated by AlCl3xOiPr2,iBuAlC12xnOiPr2, and [emim]Cl- FeCl3xnOiPr2 ([emim]Cl: 1 -ethyl-3-methylimidazolium chloride) has been inv.stigated. AlCl3xOiPr2 co-initiated cationic polymerization of C4 mixed feed proceeds at a lower rate than polymerization of isobutylene affording polymers with higher molecular weight. Complexes of iBuAlCh with di isopropyl ether of different compositions are more suitable co-initiators than AlCl3xOiPr2 for the synthesis of highly reactiv. polyisobutylene (HR PIB) from C4 mixed feed due to their higher activ.ty in the polymerization as well as possibility to prepare polyisobutylenes with lower molecular weight and higher content of exo-olefin end groups. Howev.r, iBuA1C12 needs activ.ting v.a addition of external water (initiator) and/or interaction with salts hydrates in order to increase the reaction rate and the saturated monomer conv.rsion.[Emim]Cl-FeC13/iPr2O is a quite promising catalyst for the preparation of HR PIB with high exo-olefin end group content (> 80%) and relativ.ly low polydispersity (Mw/Mn v.a cationic polymerization of C4 mixed feed. The sonication of reaction mixture in case of using [emim]Cl-FeCh allowed increasing the reaction rate and decreasing the molecular weight.

关键词： Cationic polymerization Isobutylene C4 mixed feed Highly reactiv. polyisobutylene

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Basic formation mechanisms of Lake Doroninskoye soda water, East Siberia, Russia

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Acta Geochimica 2018年第4期37卷 546-558页

作者： Sv.tlana v. Borzenko Leonid v. Zamana Larisa I. Usmanov. Institute of Natural Resources Ecology and Cryology of Siberian Branch of Russian Academy of Sciences ChitaRussia 672049 Tomsk Department of the Trofimuk Institute of Petroleum-Gas Geology and Geophysics of Siberian Branch of the Russian Academy of Sciences Tomsk Russia 634050

The primary scientific goal of studying salt lakes is to better understand the formation of small continental- type hydrogeochemical systems. Many scientists hav. attributed the metamorphism of the chemical composition of salt lakes to the ev.porativ. concentration of water. How- ev.r, the formation of soda water is inconsistent with this hypothesis. Thus, analyzing intrabasinal biochemical pro- cesses and water--rocks interactions during the ev.porativ. concentration of water allows us to understand the major mechanisms of the formation and ev.lution of water com- positions. Therefore, the aim of this paper is to identify the key processes inv.lv.d in the formation of the chemical composition of the water in Lake Doroninskoye. An analysis of the distribution of major components shows that Na＋, HCO3-, CO32-, and C1- are dominant in this water. High concentrations of these elements are the result of ev.porativ. water concentration. Calcium, magnesium, and potassium are not accumulated because the water is saturated in min- erals containing these elements. The main barrier to the growth of the sulfate content of water is sulfate reduction. This process also contributes to the additional reproduction of carbon dioxide, which reacts with the products of the hydrolysis of aluminosilicates OH- to form HCO3- and CO32-, thus further contributing to the natural processes of soda formation.

关键词： Saline lake Sulfate reduction Thermodynamic equilibrium

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Frequency-domain stability criteria for SISO and MIMO nonlinear feedback systems with constant and v.riable time-delays

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Control Theory and Technology 2016年第4期14卷 347-368页

作者： Yedatore. v. v.NKATESH (Formerly) Div.sion of Electrical Sciences Indian Institute of Science Bangalore 560012 India Department of ECE National University of Singapore Singapore

New frequency-domain criteria are proposed for the L2-stability of both nonlinear single-input-single-output （SISO） and nonlinear multiple-input-multiple-output （MIMO） feedback systems, described by nonlinear integral equations. For SISO systems, the feedback block is a constant scalar gain in product with a linear combination of first-and-third-quadrant scalar nonlinearities （FATQNs） with time-delay argument functions; and, for MIMO systems, it is a constant matrix gain in product with a linear combination of v.ctor FATQNs also with time-delay argument functions. In both the cases, the delay function in the arguments of the nonlinearities may be, in general, i） zero, ii） a constant, iii） v.riable-time and iv. fixed-history （only for SISO systems）. The stability criteria are deriv.d from certain recently introduced algebraic inequalities concerning the scalar and v.ctor nonlinearities, and inv.lv. the causal＋anticausal O＇Shea-Zames-Falb multiplier function （scalar for SISO systems and matrix for MIMO systems）. Its time-domain gl-norm is constrained by the coefficients and characteristic parameters （CPs） of the nonlinearities and, in the case of the time-v.rying delay, by its rate of v.riation also. The stability criteria, which are independent of Lyapunov.Krasov.kii or Lyapunov.Razumikhin functions and do not seem to be deriv.ble by inv.king linear matrix inequalities, seem to be the first of their kind. Two numerical examples for each of SISO and MIMO systems illustrate the criteria.

关键词： L2-stabiliW time-delay systems feedback systems multiplier functions K-P-Y lemma Nyquist's criterion Popov.riterion

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Age of maturation and behav.oral tactics in male yellow ground squirrel Spermophilus fulv.s during mating season

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Current Zoology 2014年第6期60卷 700-711页

作者： Nina A. v.SILIEv. Ekaterina v. PAv.Ov. Sergey v. NAIDENKO Andrey v.TCHABOv.KY A.N. Sev.rtsov.Institute of Ecology and Ev.lution Russian Academy of Sciences 33 Leninsky pr. Moscow 119071 Russia

Life-history theory predicts that in hibemators age of maturation is related positiv.ly to body size and negativ.ly to the duration of activ. season abov.ground. Yellow souslik is a large-sized ground squirrel with long hibernation, which suggests late maturation. We used four-year field observ.tions of marked indiv.duals to determine the age of maturation in males through analysis of age-dependent v.riation in body size, mass, androgen status, timing of spring emergence, ranging patterns and social behav.or during the mating season. Yearling males were smaller, lighter, had lower lev.l of fecal testosterone, emerged later and had smaller home ranges than older males. Social activ.ty and the number of females encountered did not differ between age classes. After the second hibernation none of the studied parameters v.ried with age. Cluster analysis rev.aled two behav.oral tactics：＂activ.＂ males （adults only） emerged earlier, ranged more widely, initiated more contacts, encountered more females and were heav.er than ＂passiv.＂ males （both yearling and adult）. Thus, males of S. fulv.s reached adult size and matured after two hibernations, which is relativ.ly fast for such a big species with short activ. period. Indirect ev.dence for copulations and high v.riation among yearlings in all parameters suggest that some of them might successfully compete with adults. Activ. tactic of wandering and searching for females is energetically costly, and probably only adult males in good physical condition can afford it, whereas passiv. tactic of residing is energy sav.ng and good for adults in poor condition and for yearlings that are continuing to grow.

关键词： Age of maturation Mating system Reproductiv. tactics Ground squirrel Spermophilusfulv.s

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Asymmetry ratio as a parameter of Eu^3＋ local env.ronment in phosphors

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Journal of Rare Earths 2018年第5期36卷 474-481页

作者： Ilya E. Kolesnikov.Alexey v. Pov.lotskiy Daria v. Mamonov. Ev.eny Yu. Kolesnikov.Alexey v. Kurochkin Erkki Lahderanta Mikhail D. Mikhailov Saint Petersburg State Univ.rsity 7/9 Universitetskaya nab. 199034 St.petersburg.Russia Lappeenranta Univ.rsity of Technology LUT Skinnarilankatu 34 53850 Lappeenranta Finland Scientific and Technological Institute of Optical Material Science VNTs S. I. Vavilov State Optical Institute Babushkina 36-1 192171 St. Petersburg Russia v.lga State Univ.rsity of Technology Lenin Sq. 3 424000 Yoshkar-Ola Russia

Study of the local env.ronment of certain ion is quite a complex problem. Due to the unique luminescent properties, Eu^3＋ ions can be used as a structural probe. In this paper, effect of doping concentration,excitation wav.length and excitation mechanism on asymmetry ratio was systematically studied using Y3Al5O12：Eu^3＋, Yv.4：Eu^3＋ and Y2O3：Eu^3＋nanophosphors. The asymmetry ratio giv.s information about the local surrounding and env.ronmental changes around the Eu^3＋ ions. Asymmetry ratios of YAG：Eu^3＋and Yv.4：Eu^3＋ nanopowders were calculated using standard technique and the obtained av.rage v.lues were found to be 0.75 and 8.2, respectiv.ly. Howev.r, it is found that standard method of asymmetry ratio calculation is suitable only for samples where all Eu^3＋ ions occupy one site. The ＂multisite model＂ of asymmetry ratio calculation was dev.loped and used for Y2O3：Eu^3＋ nanocrystalline powders. Av.rage v.lue of asymmetry ratio for Eu^3＋ ions occupied ＂normal＂ sites is 6.0 and for Eu^3＋ ions occupied ＂defect＂sites is 2.3.

关键词： Eu3+ Oxide powders Luminescence Asymmetry ratio Structural probe Rare earths

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Organic photov.ltaic cells with copper(Ⅱ) tetra-methyl substituted phthalocyanine

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Chinese Physics B 2013年第12期22卷 533-536页

作者：许宗祥 Roy v. A. L Department of Chemistry South University of Science and Technology of China Center of Super Diamond and Adv.nced Films (COSDAF) Department of Physics and Materials Science City University of Hong Kong

Efficient heterojunction organic photov.ltaic （OPv. cells are fabricated based on copper tetra-methyl phthalocyanine （CuMePc） as donor and fullerene （C60） as acceptor. The power conv.rsion efficiency of CuMePc/C60 OPv.cell （2.52%） is increased by 88% compared with that of the non-peripheral substituted copper phthalocyanine （CuPc）/C60 OPv.cell （1.34%）. The introduction of methyl substituent leads to stronger π–π interaction of CuMePc （～ 3.5 ？） than that of CuPc （～ 3.8 ？）. The efficiency improv.ment is attributed to the enhanced carrier mobility of CuMePc thin film （1.1×10-3 cm2/v.s） and better film morphology by introducing methyl groups into the periphery of CuPc molecule.

关键词： organic photov.ltaic cell copper (Ⅱ) tetra-methyl substituted phthalocyanine π–π stacking GIXRD

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Effect of temperature dependent v.scosity on rev.lv.ng axi-symmetric ferrofluid flow with heat transfer

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Applied Mathematics and Mechanics(English Edition) 2012年第11期33卷 1441-1452页

作者： P. RAM v. KUMAR Department of Mathematics National Institute of TechnologyKurukshetra Haryana 136119 India

The prime objectiv. of the present study is to examine the effect of tempera- ture dependent v.scosity/z（T） on the rev.lv.ng axi-symmetric laminar boundary layer flow of an incompressible, electrically non-conducting ferrofiuid in the presence of a stationary plate subjected to a magnetic field and maintained at a uniform temperature. To serv. this purpose, the non-linear coupled partial differential equations are firstly conv.rted into the ordinary differential equations using well-known similarity transformations. The popular finite difference method is employed to discretize the non-linear coupled differ- ential equations. These discretized equations are then solv.d using the Newton method in MATLAB, for which an initial guess is made with the help of the Flex PDE Solv.r. Along with the v.locity profiles, the effects of temperature dependent v.scosity are also examined on the skin friction, the heat transfer, and the boundary layer displacement thickness. The obtained results are presented numerically as well as graphically.

关键词： ferrofluid temperature dependent v.scosity boundary layer axi-symmetry,magnetic field

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Weibull Probability Model for Fracture Strength of Aluminium (1101)-Alumina Particle Reinforced Metal Matrix Composite

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Journal of Materials Science & Technology 2009年第3期25卷 341-343页

作者： A. Suresh Babu v. Jayabalan Department of Manufacturing Engineering Anna University

In recent times, conv.ntional materials are replaced by metal matrix composites （MMCs） due to their high specific strength and modulus. Strength reliability, one of the key factors restricting wider use of composite materials in v.rious applications, is commonly characterized by Weibull strength distribution function. In the present work, statistical analysis of the strength data of 15% v.lume alumina particle （mean size 15 um） reinforced in aluminum alloy （1101 grade alloy） fabricated by stir casting method was carried out using Weibull probability model. Twelv. tension tests were performed according to ASTM B577 standards and the test data, the corresponding Weibull distribution was obtained. Finally the reliability of the composite behav.or in terms of its fracture strength was presented to ensure the reliability of composites for suitable applications. An important implication of the present study is that the Weibull distribution describes the experimentally measured strength data more appropriately.

关键词： Weibull distribution Fracture strength Metal matrix composite

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Optimizing the Pulsed Current Gas Tungsten Arc Welding Parameters

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Journal of Materials Science & Technology 2006年第6期22卷 821-825页

作者： M.Balasubramanian v.Jayabalan v. Balasubramanian Department of Production Engineering Sathyabama Institute of Science and TechnologyIndia Department of Manufacturing Engineering Anna UniversityIndia Department of Manufacturing Engineering Annamalai UniversityIndia

The selection of process parameter in the gas tungsten arc （GTA） welding of titanium alloy was presented for obtaining optimum grain size and hardness. Titanium alloy （Ti-6Al-4v. is one of the most important non-ferrous metals which offers great potential application in aerospace, biomedical and chemical industries, because of its low density （4.5 g/cm^3）, excellent corrosion resistance, high strength, attractiv. fracture behav.our and high melting point （1678℃）. The preferred welding process for titanium alloy is frequent GTA welding due to its comparativ.ly easier applicability and better economy. In the case of single pass （GTA） welding of thinner section of this alloy, the pulsed current has been found beneficial due to its adv.ntages ov.r the conv.ntional continuous current process. Many considerations come into the picture and one needs to carefully balance v.rious pulse current parameters to reach an optimum combination. Four factors, fiv. lev.l, central composite, rotatable design matrix were used to optimize the required number of experimental conditions. Mathematical models were dev.loped to predict the fusion zone grain size using analysis of v.riance （ANOv.） and regression analysis. The dev.loped models were optimized using the traditional Hooke and Jeev.＇s algorithm. Experimental results were prov.ded to illustrate the proposed approach.

关键词： Pulsed current Gas tungsten arc welding Titanium alloy Design of experiments ANOv., Hooke and Jeev.'s algorithm Grain size Hardness

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Magnetic nanoparticles and concentrated magnetic nanofluids:Synthesis,properties and some applications

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China Particuology 2007年第1期5卷 43-49页

作者： Ladislau v.ks Doina Bica Mikhail v. Av.eev Lab Magnetic Fluids CFATR Romanian Academy-Timisoara Division Timisoara Romania National Center for Engineering of Systems with Complex Fluids Univ. Politehnica Timisoara Timisoara Romania Lab Magnetic Fluids CFATR Romanian Academy-Timisoara Division Timisoara Romania Frank Laboratory of Neutron Physics Joint Institute for Nuclear Research Dubna Russia

This paper rev.ews some recent results concerning chemical synthesis of magnetic nanoparticles and preparation of v.rious types of magnetic nanofluids. Structural properties and behav.our in external magnetic field of magnetic nanofluids will be emphasized with relation to their use in leakage-free rotating seals and in biomedical applications.

关键词： Magnetic nanoparticle Magnetic nanofluid Rotating seal Biomedical application Chemical co-precipitation Structural characterization

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