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1.
The dynamics of π-cell liquid crystal displays was studied by detailed computer simulation. The time evolution of the director configuration and the velocity of flow reveals the mechanism of the fast response of π-cells. The effect of pretilt angle on the dynamics of π-cells was also studied. 相似文献
2.
New unconventional T-shaped non-symmetrical dimeric liquid crystalline compounds have been synthesised and their thermotropic properties studied on the hot-stage of a polarising microscope. These compounds consist of an azo-ester mesogenic unit with a range of terminal substituents (–CH3, –OCH3, –NO2 or –Cl) at one end, interconnected by a flexible spacer (n?=?4, 5 or 10) via ether and ester linking units to a biphenyl moiety at the lateral hydroxyl position of the azo-ester. All the compounds were characterised using a combination of elemental analysis and standard spectroscopic methods. The compounds were found to exhibit enantiotropic nematic and smectic mesophases. The effect of different terminal substituents on mesomorphism is discussed. 相似文献
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I.IntroductionItisimportanttoresearchnon-symmetricalquestionsofshallowcollicalshellsintheoryoronapplication.Asonekindofpressurevessel'sparts,shallowconicalshellsareverycommonlyusedillellgineerillgpractice,becausethedifficultyofmanul\lctul.illgthemis'small.AlthotlghwelookupmanyChineseandtbreignperiodicalswhicharctlblctobefound,wehavenotyeth'ulldarticlesanddocumentsfornon-symmetricalandnolllinearquestionsofshitllowconictllshells.Oval'rccelltyears,ProlbssorWangXinzhiandhiscolleagueshavedonealot… 相似文献
5.
Roman Klimkiewicz Hanna Grabowska Ludwik Syper 《Reaction Kinetics and Catalysis Letters》2000,69(1):137-143
The catalytic conversion of esters and mixtures of alcohols and aldehydes in the gas phase over iron oxide has been studied. The method allows for effective synthesis of non-symmetrical ketones. 相似文献
6.
We have proposed a novel noncontact ultrasonic motor based on
non-symmetrical electrode driving. The configuration of this
electrode and the fabrication process of rotors are presented. Its vibration
characteristics are computed and analysed by using the finite element
method and studied
experimentally. Good agreement between them is obtained. Moreover,
it is also shown that this noncontact ultrasonic motor is operated in
antisymmetric radial vibration mode of $B_{21}$ mode. The maximum revolution
speed for three-blade and six-blade rotors are 5100 and 3700\,r/min at an
input voltage of 20V, respectively. Also, the noncontact high-speed
revolution of the rotors can be realized by the parts of I, III of the
electrode or
II, IV of the electrode. The levitation distance between the stator and
rotor is
about 140$\mu $m according to the theoretical calculation and the experimental
measurement. 相似文献
7.
本文根据板的基本理论,在文献 ̄[1]的基础上对因接圆环板在集中力作用下进行了求解,进而提出计算固接圆环板在非对称载荷作用下应力与应变的方法,并编制了计算程序。本文中还进行了有限元分析,二者符合较好。本文的方法和程序可用于有关的工程计算设计。 相似文献
8.
magnetohydrodynamic (MHD) power generator system involves several subjects such as magnetohydrodynamics, plasma physics, material science, and structure mechanics. Therefore, the performance of the MHD power generator is affected by many factors, among which the load coefficient k is of great importance. This paper reveals the effect of some system parameters on the performance by three-dimensional (3D) numerical simulation for a Faraday type MHD power generator using He/Xe as working plasma. The results show that average electrical conductivity increases first and then decreases with the addition of magnetic field intensity. Electrical conductivity reaches the maximum value of 11.05 S/m, while the applied magnetic field strength is B = 1.75 T. When B > 3T, the ionization rate along the midline well keeps stable, which indicates that the ionization rate and three-body recombination rate (three kinds of particles combining to two kinds of particles) are approximately equal, and the relatively stable plasma structure of the mainstream is preserved. Efficiency of power generation of the Faraday type channel increases with an increment of the load factor. However, enthalpy extraction first increases to a certain value, and then decreases with the load factor. The enthalpy extraction rate reaches the maximum when the load coefficient k equals 0.625, which is the best performance of the power generator channel with the maximum electricity production. 相似文献
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A new optically active chiral moiety, (S)‐1‐propyloxy‐2‐propanol, was designed and synthesized by the treatment of 1‐propanol with (S)‐propylene oxide under basic conditions. Its derivatives, the (R)‐1‐propyloxy‐2‐propyl 4‐[4‐(4‐alkoxyphenyl)phenoyloxy]benzoates, PPmPPB (m = 8–12), were prepared for the investigation of mesomorphic properties. All of the chiral materials displayed enantiotropic SmA? and SmC? phases, and the shorter alkyl chain members (m = 8–11) displayed an additional unidentified SmX? phase. The switching current, spontaneous polarization, tilt angle, dielectric constant and electro‐optical response for the materials in the ferroelectric SmC? phase were measured. The electro‐optic responses in polyimide film‐coated homogeneously aligned cells exhibit thresholdless, V‐shaped switching in the ferroelectric phase. 相似文献