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1前言在两相分离中,液一液两相的分离是最困难的。主要是两相密度差较小且物性较为接近,在多相流体手册山等理论参考书中尚没涉及到液一液分离这个领域,随着近海及海上油田的开发生产及环保的要求,人们对油水二次分离提出了更高要求,工业上油水分离多采用浮选和重力沉降的方法,不适于近海及海上油水分离的情况,旋流分离技术具有体积小,重量轻,处理时间短,任意取向,不受振动影响等优点,因而开展低密度差液一液两相旋流分离的研究具有学术意义和工程应用背景。ZI质流程及试验方法工质流程为油水两相均匀的混合物由水箱用泵抽出,… 相似文献
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电流变液的研究进展及应用前景 总被引:3,自引:0,他引:3
电场致流变液体(电流变液)是一些高介电小颗粒和低介电油液的混合体,它在高电场作用下呈现液体与固体间的变换,变换时间为几毫秒,而且变换可逆。阐明了电流变液的原理,综述了电流变液在机制、材料及应用等方面的研究现状,并介绍了电流变液在技术和工业上广泛的应用前景。 相似文献
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研究了纳米二氧化钛包覆高岭土和钇掺杂钛酸钡两种电流变液的微波反射行为.实验发现,在垂直于微波传播方向电场作用下,两种电流变液微波反射系数均随电场强度的增大而增大;钇掺杂钛酸钡电流变液微波反射系数变化幅度比二氧化钛包覆高岭土电流变液宽,并且电场调节的能力随浓度的增加有减弱的趋势.对钇掺杂钛酸钡电流变液存在一个临界浓度,低于这个浓度,电场的调控能力随电场强度的增加而增大,高于这个浓度,电场的调控能力随电场的增加先增大后减小.另外,二氧化钛包覆高岭土电流变液反射回波相位随电场强度的增大出现最大值后逐渐减小趋于平
关键词:
电流变液
微波反射
相位 相似文献
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Jason M. Porter Jay B. Jeffries Ronald K. Hanson 《Journal of Quantitative Spectroscopy & Radiative Transfer》2009,110(18):2135-2147
Quantitative absorption spectra for several hydrocarbon fuels in the liquid phase at are presented. Measurements of toluene, n-dodecane, n-decane, and three samples of gasoline were made over the spectral region 2700–3200 to support the development of mid-infrared laser-absorption diagnostics for measurements of fuel vapor in the presence of liquid films and aerosols. A procedure for quantitative Fourier transform infrared (FTIR) absorption measurements of strongly absorbing liquids is described and the resulting absorption spectra are compared with previously measured absorption spectra in the vapor phase. The measured absorption spectra for liquid gasoline are shown to scale with the volume percent of olefin, alkane, and aromatic hydrocarbons in each sample. Finally, the observed frequency shift of in the spectra of vapor and liquid hydrocarbons is discussed, including the potential for measurements of fuel vapor in the presence of liquid films. 相似文献
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介绍了EAST 装置离子回旋加热系统中的两种实现阻抗匹配的方式, 用三支节液态调配器取代传统的滑竿式三支节调配器和用液态相移器与单支节液态调配器相结合组成液态阻抗匹配系统。通过对液态阻抗匹配系统的分析, 表明这两种方式都能够较好地实现阻抗匹配。 相似文献
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Summary The nematic planar anchoring is usually explained by using simple elastic models: the surface easy axis corresponds to the
surface direction that minimizes the excess of nematic elastic energy. When anisotropic rough substrates are used to align
nematic liquid crystals, due to the complex surface morphology, usual elastic models are not directly applicable. This paper
presents quantitative topographical data of rough substrates, obtained with oblique SiO evaporation under vacuum for nematic
planar anchoring. Experimental data are obtained by means of Atomic Force Microscopy and they are used to demonstrate the
self-affine nature of these substrates and to relate the nematic anchoring with the anisotropy of the local fractal properties
of the substrate itself.
Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994. 相似文献
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A. L. Alexe-Ionescu 《Il Nuovo Cimento D》1993,15(12):1489-1506
Summary The elastic deformations in nematic liquid crystals are analysed in one and two dimensions. The influence of the flexoelectric
polarization on the elastic properties of the medium is studied. It is shown that for one-dimensional deformations, the presence
of the flexoelectric polarization introduces a renormalization of the elastic constants. On the contrary in the bidimensional
case, the effect of the flexoelectricity is not a simple renormalization of the elastic constants. The profiles of the electric
potential and of the tilt angle are evaluated for the cases in which the substrate is an insulating or conducting material.
The validity of the calculations is discussed by considering the value of Debye's screening length of the nematic liquid crystal. 相似文献
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Summary A single domain nematic liquid crystal undergoes first- or second-order transitions when placed in an external field (Fréedericksz
transition). A new type of transition, giving rise to a periodic distortion of the mean molecular direction, within particular
ranges of the elastic-constant ratio, has been recently studied. In this paper we show that, in a particular situation involving
an electric and a magnetic field, both perpendicular to the director, and nonsymmetric boundary conditions, the periodic Fréedericksz
transition is forbidden for any value of the elastic-constant ratio.
Riassunto Un cristallo liquido nematico orientato in modo uniforme subisce una transizione orientazionale del primo o del secondo ordine quando è sottoposto ad un campo esterno (transizione di Fréedericksz). Recentemente è stato studiato un nuovo tipo di transizione che, per particolari valori del rapporto delle costanti elastiche, consiste in una distorsione periodica della direzione molecolare media. In questo lavoro si mostra che quando sono presenti due campi, elettrico e magnetico, incrociati e perpendicolari all’orientazione indisturbata del nematico, e le condizioni al contorno non sono simmetriche (ancoraggio forte/debole), non si ha piú transizione periodica di Freédericksz, per qualunque valore del rapporto tra le costanti elastiche.
Резюме Однодоменный нематический жидкий кристалл претерпевает переходы первого или второго порядка во внешнем поле (переход Фрпдерикса). Недавно был исследован новый тип перехода, вызывающий периодическую дисторсию среднего молекулярного направления в некоторых областях отношения упругих постоянных. В этой системе мы показываем, что для определен электрических и магнитных полей, перпендикулярных директоры, и несимметричных граничных условий периодический переход Фридерикса оказывается запрещенным для любых значений отношения упругих постоянных.相似文献
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Summary The current understanding of the problems concerning the fog phase structure organization based upon experimental results
of our group is presented. The correspondence between theoretical models and experimental results is discussed.
Work presented at the second USSR-Italy Bilateral Meeting on Liquid Crystals held in Moscow, September 15–21, 1988. 相似文献
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Summary Langmuir-Blodgett films of a number of native proteins have been prepared and their activities confirmed. The possibility
of exploiting these layers in immunosensing structures is also reported.
Work presented at the second USSR-Italy Bilateral Meeting on Liquid Crystals held in Moscow, September 15–21, 1988. 相似文献
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Summary By means of a phenomenological approach, we demonstrate that the mixed splay-bend elastic constantK
13 in the free energy density of nematic liquid crystals must be considered zero, unless the bulk contributions of the squares
of the distortion second-order derivatives are taken into account, together with the squares of the first-order derivatives
times the second-order derivatives, and with the fourth powers of the first-order derivatives. Such contributions just reduce
to one in the presence of—and close to—a threshold. Furthermore, the saddle-splayK
24-term instead is shown always to play an essential role, as the bulk first-order elasticity, in determining the distortion
free energy of nematics with weak anchoring subjected to spatial deformations. Finally, the new surfacelike elastic constants
are shown to have a nilpotent character: thus they behave as well asK
24 from the point of view of the variational calculus.
Work presented at the second USSR-Italy Bilateral Meeting on Liquid Crystals held in Moscow, September 15–21, 1988. 相似文献
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G. Bossi B. Dubini P. Mariani M. G. Ponzi Bossi F. Rustichelli R. S. Phadke 《Il Nuovo Cimento D》1990,12(9):1293-1308
Summary We report a thermodynamical and structural investigation on the effect of a dicarboxylic acid, the azelaic acid, on a synthetic
phosophatidylcholine in excess water condition. The results indicate that the drug interacts with the lipid headgroup region,
near to the hydrocarbon chains: in particular, at higher concentrations investigated, an interdigitated ?gel phase?, with
rigid chains, stiff and perpendicular to the lamellar planes, is induced. The experimental electron density profiles, obtained
for samples containing low and high quantity of azelaic acid, support the proposed interaction. Moreover, step electron density
models, used to confirm the selected sign combination of the observed structure factors, show the best agreement with the
experimental data when the chain terminal methyl groups are frozen in fixed position.
Work presented at the second USSR-Italy Bilateral Meeting on Liquid Crystals held in Moscow, September 15–21, 1988. 相似文献
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Summary Close to the interface between a nematic liquid crystal (NLC) and another medium, the elastic constants become functions of
distancez from the interface and of angle θ between the directorn and the unit vectork orthogonal to the interface. Furthermore, due to the breaking of the translation symmetry at the interface, a lot of new
subsurface elastic contributions can appear. In a previous paper we investigated these subsurface anomalies by using a simple
molecular model based on induced-dipole-induced-dipole interactions and by making numerical calculations in the special case
of a planar director distortion. In this way, only the numerical values of some effective subsurface elastic constants that
characterise planar director distortions could be obtained. In this paper we make a more complete analytical calculation of
all the subsurface elastic constants by using a microscopic model and a more general theoretical procedure. The microscopic
interaction energy is written in a general form that allows us to investigate different kinds of intermolecular interactions
(induced diple-induced dipole, quadrupole-quadrupole and so on). Both thez-dependence and the θ-dependence of the subsurface elastic constants are obtained in a closed analytical form. In the special
case of induced-dipole-induced-dipole interactions and for planar director distortions, our analytical results are shown to
agree with the previous numerical results. The important macroscopic effect of these elastic subsurface anomalies is discussed. 相似文献