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Local Well-Posedness for the Compressible Nematic liquid crystals Flow with Vacuum

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Analysis in Theory and Applications 2020年第4期36卷 497-509页

作者： Jishan Fan Fucai Li Gen Nakamura Department of Applied Mathematics Nanjing Forestry UniversityNanjingJiangsu 210037China Department of Mathematics Nanjing UniversityNanjingJiangsu 210093China Department of Mathematics Hokkaido UniversitySapporo 060-0810Japan

In this paper we prove the local well-posedness of strong solutions to the compressible nematic liquid crystals flow with vacuum in a bounded domainΩ■R3.

关键词： liquid crystals vacuum Local well-posedness strong solution.

High-Resolution Heat Transfer Coefficients Measurement for Jet Impingement Using Thermochromic liquid crystals

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Chinese Journal of Aeronautics 2001年第4期14卷 205-209页

作者：张靖周李立国 Coll. of Energy and Power Eng. Nanjing Univ. of Aero. and Astro. Nanjing 210016 China

A high-resolution testing technique named liquid crystal thermography is used for the experimental study on jet array impingement to map out the distribution of heat transfer coefficients on the cooling surface. Effects of the impingement distance, the impinging hole arrangement and the initial crossflow on heat transfer characteristics are investigated. The thermal images show truly the features of local heat transfer for each jet impingement cooling. The applications of thermochromic liquid crystal are successful in the qualitative and quantitative measurement for heat transfer coefficients distribution.

关键词： Cooling Flow visualization Heat transfer coefficients Jets liquid crystals Thermography (imaging)

The Freedericksz Transition and the Asymptotic Behavior in Nematic liquid crystals

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Journal of Partial Differential Equations 2012年第3期25卷 276-294页

作者： ARAMAKI Junichi Division of Science Faculty of Science and Engineering Tokyo Denki University Hatoyama-machi Saitama 350-0394 Japan.

We consider the stability of a specific nematic liquid crystal configuration under an applied magnetic field. We show that for some specific configuration there exist two critical values Hn and Hsh of applied magnetic field. When the intensity of the magnetic field is smaller than Hn, the configuration of the energy is only global minimizer, when the intensity is between Hn and Hsh, the configuration is not global minimizer, but is weakly stable, and when the intensity is larger than Hsh, the configuration is instable. Moreover, we also examine the asymptotic behavior of the global minimizer as the intensity tends to the infinity.

关键词： Freedricksz transition variational problem liquid crystals Landau-de Gennes functional.

Dithiophene Based X-Shaped Bolaamphiphiles:liquid crystals with Single Wall Honeycombs and Geometric Frustration

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Dithiophene Based X-Shaped Bolaamphiphiles:Liquid Crystals w...

Synthesis and Thermal Behaviour of Lanthanide Complexes of 4′[（Cholesteryloxy）Carbonyl]—Benzo—15—Crown—5

全国第十六届大环化学暨第八届超分子化学学术讨论会

作者：程晓红 Chemistry Department Yunnan University

＜正＞A series of 5,5’-diphenyl-2,2’-dithiophene based X-shaped polyphiles form square（p4mm and p4gm） and hexagonal（p6mm） columnar LC *** these mesophases the molecules organize into polygonal honeycombs where theπ-conjugated cores form the walls,fused at the edges by the hydrogen bonding networks between the glycerol units and filled by the lateral alkyl *** elongation of these chains a

关键词： liquid crystals thiophene polygonal honeycombs

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Journal of Rare Earths 2002年第4期20卷 249-255页

作者： KoenBinnemans BilgiCuendogan Dept. of Chem. Katholieke Univ. Leuven B-3001 Leuven Celestijnenlaan 200F Belgium

Lanthanide complexes of a steroid-substituted benzocrown ether were synthesised. The metal-to-ligand ratio of all the metal complexes is 1∶1. The ligand 4′-[(cholesteryloxy)carbonyl]-benzo-15-crown-5 is a monotropic liquid crystal, displaying a cholesteric mesophase. The lanthanide complexes with nitrate counter-ions form a highly viscous mesophase, decomposing at the clearing point. The transition temperatures change as a function of the lanthanide ion. The corresponding lanthanide complexes with dodecylsulphate (DOS) counter-ions do not form a mesophase. In both cases, the metal complexes have a much lower melting point than the parent ligand.

关键词： rare earths lanthanide compounds metallomesogens liquid crystals crown ether

Influence of Magnetic Field and Lighting during the Creation Process of Nanohybrid Semiconductor-Nematic Structures on Their Impedance and Photo Response

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Journal of Materials Science & Technology 2011年第11期27卷 973-978页

作者： Fedir Ivashchyshyn Ivan Grygorchak Olena Sudakova Igor Bordun Miroslav Micov Lviv Polytechnic National University 12 Bandera Str. Lviv 79013 Ukraine

In this work, for the first time, photosensitive nanostructures with alternate semiconductor and magnetic oriented nematic molecular nanolayers were obtained. The established dependency on the ordering type of kinetic and optical properties is deserving attention. For the first time, the notion of ＇rotary＇ polaron in such structures is introduced and microscopic model is created, which explains band structure transformation. The model is well coordinated with experimental optical data, which, at the same time, indicate the prospects of application of materials obtained due to the intercalation engineering for photoenergetics.

关键词： Nanocomposites Heterostructures Intercalation liquid crystals Impedancespectroscopy Photoelectromotive force

The Shackling Effect in Cyclic Azobenzene liquid Crystal

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Chinese Journal of Polymer Science 2022年第6期40卷 584-592页

作者： Yang Xiao Chong He Zi-Fan Yang Er-Qiang Chen Huan-Jun Lu Xiao-Hong Li Ying-Feng Tu State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of ChemistryPeking UniversityBeijing 100871China Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application School of Physical Science and TechnologySuzhou University of Science and TechnologySuzhou 215009China

We demonstrate here a novel method for the design of liquid crystals(LCs)via the cyclization of mesogens by flexible *** two azobenzene-4,4′-dicarboxylate derivatives,the cyclic dimer,cyclic bis(tetraethylene glycol azobenzene-4,4′-dicarboxylate)(CBTAD),shows LC properties with smectic A phase,while its linear counterpart,bis(2-(2′-hydroxyethyloxy))ethyl azobenzene-4,4′-dicarboxylate(BHAD),has no LC *** difference is ascribed to the shackling effect from the cyclic topology,which leads to the much smaller entropy change during phase transitions and increases the isotropic temperature greatly for *** addition,the trans-to-cis isomerization of azobenzene groups under UVlight is also limited in *** the reversible isomerization of azobenzene groups,CBTAD showed interesting isothermal phase transition behaviors,where the LC phase disappeared upon photoirradiation of 365 nm UV-light,and recovered when the UV-light was *** with the smectic LC nature,a novel UV-light tuned visible light regulator was designed,by simply placing CBTAD in two glass *** scattered phase of smectic LC was utilized as the“OFF”state for light passage,while the UV-light induced isotropic phase was utilized as the“ON”*** shackling effect outlined here should be applicable for the design of cyclic LC oligomers/polymers with special properties.

关键词： Azobenzene Cyclic liquid crystals Isothermal phase transition

Design and Fabrication of Reflective Phase Shifter for Two-Dimensional Terahertz Beam-Scanning Reflectarray

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Chinese Journal of Electronics 2022年第3期31卷 581-588页

作者： YANG Jun YIN Mingjun GAO Haoyu YIN Zhiping YE Yang DENG Guangsheng LU Hongbo Special Display and Imaging Technology Innovation Center of Anhui Province Academy of Opto-electric TechnologyHefei University of Technology Guangxi Key Laboratory of Wireless Wideband Communication and Signal Processing Guilin University of Electronic Technology Space Star Technology Co. Ltd.

A reflective phase shifter is proposed to realize the two-dimensional beam-scanning *** reflectarray is composed of double-dipole resonant elements in which the phase shift is implemented by applying a driving voltage to the liquid crystal(LC). A 30 ×30 phase shifter sample is fabricated on a quartz substrate with a 480 μm thickness and a 4 cm × 4 cm *** to the experimental results, 0 to 360° phase shift can be achieved within the bandwidth of 5 GHz. In order to accomplish two-dimensional beam-scanning and reduce the negative impact of driving lines on the reflectarray, a new LC driving method is developed. To verify the accuracy of the proposed approach, three samples of different driving line numbers are designed using the above-mentioned phase shifter, which all have achieved a0-360° phase shift in the bandwidth of 4 GHz. Considering the influence of LC anisotropy and inhomogeneity, an improved calculation result is obtained and compared with experimental data.

关键词： liquid crystals phase shifters above-mentioned phase shifter reflective phase shifter double-dipole resonant elements submillimetre wave antennas LC anisotropy two-dimensional terahertz beam-scanning reflectarray driving voltage dipole antenna arrays scanning antennas driving line numbers LC driving method reflectarray antennas

Measurements of heat transfer and pressure in a trailing edge cavity of a turbine blade

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Chinese Journal of Aeronautics 2013年第2期26卷 294-308页

作者： Wu Hong Liu Yusheng Xu Guoqiang National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics School of Energy and Power Engineering Beihang University

An experimental investigation is conducted to obtain the heat transfer and pressure drop data for an integral trailing edge cavity test section that simulates a novel turbine blade＇s internal cooling passage with bleed holes. Local heat transfer is measured on both the suction and pressure sides by a transient liquid crystal technique, while pressures at six positions are recorded by pressure calibrators. Moreover, flow characteristic and its effect on heat transfer are analyzed for conditions with or without bleed flow. The experimental results show that, in the cases with bleed flow, local heat transfer on the pressure side exceeds that on the suction side in the first and second channels. In the cases without bleed flow, in the first and third channels, local heat transfer on the suction side weakens whilst it increases significantly on the pressure side. For the second channel, non-bleed condition leads to a more balanced heat transfer distribution between the upstream and downstream channel. Besides, after the bleed holes are blocked, heat transfer in the first bend region on the suction side declines sharply, while the opposite phenomenon occurs for the second bend region on the pressure side. In both bleed and non-bleed cases, the total pressure of six measurement positions decreases continuously along the channel at the same Reynolds number and it promotes for higher Reynolds number. Among all the measurement points, under the same flow rate condition, the highest speed occurs at Position 5, which also shows the maximum difference between the total and static pressures. When the bleed holes are blocked, the total pressure at each measurement position appears to increase.

关键词： Bleed flow Cooling Gas turbines Heat transfer liquid crystals Transient