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51.
在一300×2600mm二维双射流流化床中,采用多路压力信号采集装置,详细研究了射流气速、射流喷口管间距离、静床高度、物性参数对双射流流化床射流流动特性的影响,发现双射流从单独存在到两射流在其射流区内发生射流合并可由压力波动时间序列的功率谱主频和Hurst指数的变化定量确定,结果还表明,双射流流化床管间距减小时,射流在射流区发生合并的射流气速降低;而管间距相同时,静床高变大,射流在射流区发生合并的射流气速也降低;对于相同粒径的固体颗粒,颗粒密度增大使得射流在射流区发生合并的射流气速变大。 相似文献
52.
双金属复合氧化物的结构与紫外阻隔性能 总被引：7，自引：1，他引：7
双金属复合氧化物（ＣＬＤＨ）是一类发展迅速的无机层状材料的煅烧产物,在催化、吸附等领域已获长足进展［１］,但作为紫外阻隔材料的性能研究尚鲜见报道．本文研究了不同双金属复合氧化物的紫外阻隔性能,结果发现二价金属离子为锌离子的ＣＬＤＨ具有良好的紫外阻隔性能．实验所用试剂均为分析纯．ＣＬＤＨ由ＮａＯＨ,Ｎａ２ＣＯ３,ＭｇＳＯ４·７Ｈ２Ｏ,ＺｎＳＯ４·７Ｈ２Ｏ,Ａｌ２（ＳＯ４）３·１８Ｈ２Ｏ为原料,按文献［２］方法制备．ＺｎＯ＋Ａｌ２Ｏ３复配物是按一定比例机械混合后,研磨,并在与ＣＬＤＨ相同的条件下煅烧… 相似文献
53.
N. N. Zemlyanskii I. V. Borisova A. K. Shestakova Yu. A. Ustynyuk E. A. Chernyshev 《Russian Chemical Bulletin》1998,47(3):469-474
The first stable dibenzosilafulvene, 9-{[8-(dimethylaminomethyl)-1-naphthyl]phenylsil-1-ylium}fluoren-9-ide (7a), was obtained in one step from 9-fluorenyllithium and chloro[8-(dimethylaminomethyl)-1-naphthyl]phenylsilane as a stable
solvate with THF. The structure of the zwitterionic compound7a was established by1H,13C, and29Si NMR in solution and in the solid state. The reactions of compound7a with crotonaldehyde, ethanol, and triethylethylidenephosphorane are described. The data on the synthesis of alkoxy- and alkylthiochloro-9-fluorenylsilanes
and their phosphonium salts are given.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 486–491, March, 1998. 相似文献
54.
Calixarenesareregardedasthethirdgenerationofh0stmoleculesbecauseoftheirinclusionabilitytocati0ns,anionsandneutralmoleculesI'2.Duringthepastdecademosteff0rtshavebeentakenonthefunctionalizati0n0fcalixareness0thattheycanbeappliedn0tonlyastheionoph0resintheextractionprocess','andassensitivematerialsforionelectrodes"',butalsoastheenZymemimicscatalyzingthecleavageofphosphatediesters"'.Inordertoenablethemtoincludeandrecognizelargerchemicalspecies,manyappr0acheshavebeenusedtoc0nstructoIigo-calixarene… 相似文献
55.
Effects of double substitution on the thermodynamic stabilities of nitrogen radicals 总被引：1，自引：0，他引：1
Ｓｔｕｄｉｅｓｏｎｋｉｎｅｔｉｃｓｏｆｒａｄｉｃａｌｒｅａｃｔｉｏｎｓ[1]ａｎｄｏｎＣＨｂｏｎｄｄｉｓｓｏｃｉａｔｉｏｎｅｎｅｒｇｉｅｓ(ＢＤＥ)[2]ｈａｖｅｓｈｏｗｎｔｈａｔｃａｒｂｏｎｒａｄｉｃａｌｓａｒｅｓｔａｂｉｌｉｚｅｄｂｙｅｉｔｈｅｒａｎｅｌｅｃｔｒｏｎｄｏｎａｔｉｎｇｇｒｏｕｐ(ＥＤＧ)ｏｒａｎｅｌｅｃｔｒｏｎｗｉｔｈｄｒａｗｉｎｇｇｒｏｕｐ(ＥＷＧ),ａｎｄｔｈａｔｉｆａｃａｒｂｏｎｒａｄｉｃａｌｉｓｓｕｂｓｔｉｔｕｔｅｄｗｉｔｈｂｏｔｈａｎＥＤＧａｎｄａｎＥＷＧａｔｔｈｅｓａｍｅｃｅｎ… 相似文献
56.
The starting electrophoretic motion of a porous, uniformly charged, spherical particle, which models a solvent-permeable and ion-penetrable polyelectrolyte coil or floc of nanoparticles, in an arbitrary electrolyte solution due to the sudden application of an electric field is studied for the first time. The unsteady Stokes/Brinkman equations with the electric force term governing the fluid velocity fields are solved by means of the Laplace transform. An analytical formula for the electrophoretic mobility of the porous sphere is obtained as a function of the dimensionless parameters , , , and , where a is the radius of the particle, κ is the Debye screening parameter, λ is the reciprocal of the square root of the fluid permeability in the particle, ρp and ρ are the mass densities of the particle and fluid, respectively, ν is the kinematic viscosity of the fluid, and t is the time. The electrophoretic mobility normalized by its steady-state value increases monotonically with increases in and , but decreases monotonically with an increase in , keeping the other parameters unchanged. In general, a porous particle with a high fluid permeability trails behind an identical porous particle with a lower permeability and a corresponding hard particle in the growth of the normalized electrophoretic mobility The normalized electrophoretic acceleration of the porous sphere decreases monotonically with an increase in the time and increases with an increase in from zero at . 相似文献
57.
Sohail Nadeem Mishal Nayab Kiani Anber Saleem Alibek Issakhov 《Electrophoresis》2020,41(13-14):1198-1205
The present paper addresses microvascular blood flow with heat and mass transfer in complex wavy microchannel modulated by electroosmosis. Investigation is carried out with joule heating and chemical reaction effects. Further, viscous dissipation is also considered. Using Debye–Huckel, lubrication theory, and long wavelength approximations, analytical solutions of dimensionless boundary value problems are obtained. The impacts of different parameters are examined for temperature and concentration profile. Furthermore, nature of pressure rise is also investigated to analyze the pumping characteristics. Important results of flow phenomena are explored by means of graphs. 相似文献
58.
Nikita O. Shaparenko Nikolay B. Kompan'kov Marina G. Demidova Alexander I. Bulavchenko 《Electrophoresis》2020,41(18-19):1592-1599
The structure and conductivity of AOT (sodium bis(2-ethylhexyl) sulfosuccinate) solutions (2.5 × 10−4–2.5 × 10−1 M) in n-hexadecane-chloroform mixture at the chloroform concentration from 50 to 100 vol% were studied. The diffusion ordered spectroscopy NMR study revealed that in the indicated range, the observed hydrodynamic diameter of micelles depends only on the AOT concentration and does not depend on the chloroform content. Molar fractions of free AOT molecules and those aggregated into micelles were calculated using the Lindman's law: at concentrations above 2.5 × 10−1 М, the solutions contain mostly the micelles, whereas at concentrations below 2.5 × 10−4 M, the solutions contain AOT molecules. The transition region contains both the AOT molecules and the micelles. Conductivity measurements were used to determine free charge carriers in the bulk of solutions and their contributions to conductivity. 相似文献
59.
Ali Pourjavadi Maryam Tavakolizadeh Seyed Hassan Hosseini Navid Rabiee Mojtaba Bagherzadeh 《Journal of polymer science. Part A, Polymer chemistry》2020,58(15):2062-2073
A number of synthetic hydrogels suffer from low mechanical strength. Despite of the recent advances in the fabrication of tough hydrogels, it is still a great challenge to simultaneously construct high stretchability, and self-adhesive and self-healing capability in a hydrogel. Herein, a new type of double network hydrogel was prepared based on irreversible cross-linking of polyacrylamide chains and Schiff-base reversible cross-linking between glycidyl methacrylate-grafted ethylenediamine and oxidized sodium alginate (OSA). The combination of both cross-linkings and their synergistic effect provided a novel hydrogel with high strength, stretchable, rapid self-healing, and self-adhesiveness to different material. Besides, the hydrogels with diverse OSA content could maintain their original shapes after loading–unloading tensile test. The resulting hydrogel has a great potential in various fields for supporting and load-bearing substance. 相似文献
60.
Sabine Apelt Susanne Höhne Petra Uhlmann Ute Bergmann 《Surface and interface analysis : SIA》2020,52(12):1150-1155
Active deicing of technical surfaces, such as for wind turbines and heat exchangers, currently requires the usage of heat or chemicals. Passive coating strategies that postpone the freezing of covering water would be beneficial in order to save costs and energy. One hypothesis is that pyroelectric active materials can achieve this because of the surface charges generated on these materials when they are subject to a temperature change. High-quality poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) thin films with a high crystallinity, prefererd edge-on orientation, low surface roughness, and comprised of the β-analogous ferroelectric phase were deposited by spin-coating. Freezing experiments with a cooling rate of 1 K min−1 were made on P(VDF-TrFE) coatings in order to separate the effect of different parameters such as the poling direction, film thickness, used solvent, deposition process, underlying substrate, and annealing temperature on the achievable supercooling. The topography and the underlying substrate significantly changed the distribution of freezing temperatures of water droplets in contact with these thin films. In contrast, no significant effect of the thickness, morphology, or pyroelectric effect of the as-prepared domain-state on the freezing temperatures was found. 相似文献