检索结果-南通市图书馆

Facet-dependent electro-optical properties of cholesteric liquid crystals doped with Cu2O nanocrystals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2018年第9期11卷 4836-4845页

作者： Dongyu Zhao Lihong Xu Yang Shang Xiaoxia Li Lin Guo Key Laboratory of Bio-lnspired Smart Interfacial Science and Technology Ministry of Education School of Chemistry Beijing Advanced Innovation Center for Biomedical Engineering Beihang University Beijing 100191 China Key Laboratory of Micro-Nano Measurement-Manipulation and Physics Ministry of Education School of Physics and Nuclear Energy Engineering Beihang University Beijing 100191 China

Excellent electro-optical （E-O） performances are essential for high-quality reflective cholesteric liquid crystal （LC） displays, but are often limited by the high driving voltages required by these displays. Dispersing functional nanomaterials into the LCs has emerged as a promising approach to achieve outstanding E-O properties. In this work, we report the facet-controlled E-O properties of a chiral nematic LC （N＊LC） doped with cubic, octahedral, and rhornbic dodecahedral Cu20. The outstanding E-O properties of the doped systems are related to the interaction between the liquid crystals and Cu20 dopants with different exposed crystal planes. Doping with octahedral and rhombic dodecahedral Cu20 reduces the stability of the planar state, as a result of both the surface abundance of active Cu atoms that interact with the polarized LC molecules, and the large amounts of vertexes and edges on the crystal surfaces, which accelerate the transition from the planar to the focal conic state under an applied electric field. Rhombic Cu20 is the most effective dopant for improving the E-O properties of the present LCs, resulting in a 65.31% reduction of the threshold voltage. The facet and morphology effects highlighted in this work provide a new pathway to develop excellent energy-saving meso-materials with exposed high-reactivity facets, improving their potential applications in electro-optical technologies and information displays.

关键词： Cu2O nanocrystals liquid crystals electro-optical properties host-guest systems facet-dependence

Effects of CuInS_(2)nanoparticles on the alignment control of liquid crystals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2022年第8期15卷 7542-7548页

作者： Dongyu Zhao Yuanyuan Guo Weihua Bi Xin Li Ran Duan Lin Guo Beijing Advanced Innovation Center for Biomedical Engineering School of ChemistryBeihang UniversityBeijing 100191China

liquid crystal-nanoparticle composite systems have attracted particular attention for both academic interests and applications in inducing macroscopic alignment,altering electro-optic response of the liquid crystal hosts,and generating ordered,tunable soft ***,the synthesis of two shapes of CuInS_(2)nanoparticles,tremelliform-like CuInS_(2)and frame-like CuInS_(2),and their utilization in producing uniform homeotropic alignment of liquid crystals are *** exploring the mechanism in detail,the crystal structures of CuInS_(2)nanoparticles were found to rely heavily on the reaction solvents during the growth process,which in turn play a significant role on the anchor of liquid crystal *** achieved homeotropic alignment shows high thermal stability,owing to the outstanding stability of the CuInS_(2)*** addition,combining this feasible method with parallel-aligning technique,variable pretilt angles in a range of~0.9°to~7.2°could be continuously achieved.

关键词： CuInS_(2)nanoparticles morphology liquid crystals alignment pretilt angle

Monodomain liquid crystals of Two-Dimensional Sheets by Boundary-Free Sheargraphy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2022年第12期14卷 14-26页

作者： Min Cao Senping Liu Qingli Zhu Ya Wang Jingyu Ma Zeshen Li Dan Chang Enhui Zhu Xin Ming Yingjun Liu Yanqiu Jiang Zhen Xu Chao Gao MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringKey Laboratory of Adsorption and Separation Materials and Technologies of Zhejiang ProvinceZhejiang University38 Zheda RoadHangzhou 310027People’s Republic of China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering TaiyuanPeople’s Republic of China State Key Lab of Chemical Engineering College of Chemical and Biological EngineeringZhejiang University38 Zheda RoadHangzhou 310027People’s Republic of China

Eliminating topological defects to achieve monodomain liquid crystals is highly significant for the fundamental studies of soft matter and building long-range ordered ***,liquid crystals are metastable and sensitive to external stimuli,such as flow,confinement,and electromagnetic fields,which cause their intrinsic polycrystallinity and topological ***,we achieve the monodomain liquid crystals of graphene oxide over 30 cm through boundary-free *** obtained monodomain liquid crystals exhibit large-area uniform alignment of sheets,which has the same optical polarized angle and *** monodomain liquid crystals provide bidirectionally ordered skeletons,which can be applied as lightweight thermal management materials with bidirectionally high thermal and electrical ***,we extend the controllable topology of two-dimensional colloids by introducing singularities and disclinations in monodomain liquid *** structures with defect strength from−2 to+2 were *** work provides a facile methodology to study the structural order of soft matter at a macroscopic level,facilitating the fabrication of metamaterials with tunable and highly anisotropic architectures.

关键词： Monodomain liquid crystals Graphene oxide Boundary-free sheargraphy Topological structure

Solitons and defects in nematic liquid crystals under a simple shear flow and in a static external magnetic field

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2008年第7期17卷 2600-2609页

作者：罗开富蒋秀丽杨玉良 Department of Macromolecular Science Key Laboratory of Molecular Engineering of Polymers of State Ministry EducationFudan University

Under a simple shear flow and in a static external magnetic field, the production of defects in the director-aligning regime of nematic liquid crystals has been investigated in terms of the Leslie-Ericksen theory. The equation of motion of the nematic director, which conforms to the driven over-damped sine-Gordon equation, has a soliton solution of the amplitude w. We show that the stationary state with the director uniformly oriented at a Leslie angle is only a metastable state and the potential, which governs the motion of the director, has a nmnber of stable stationary states. For a strong magnetic field, the higher energy barrier between the stable and unstable states leads the director to be locked along the magnetic field direction. However, at the appropriate shear rate and magnetic field the defects, which appear as a stable solitary solution, can be nucleated from a uniformly aligned nematic liquid crystal. We have calculated the stationary travelling velocity of the solitary waves and the distance between a pair of defects.

关键词： liquid crystals defects solitons

Effect of dichroic azo-dye doped on ferroelectric liquid crystals

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2008年第11期6卷 858-860页

作者：冯亚云凌志华 Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033 Graduate University of Chinese Academy of Sciences Beijing 100049

In order to study the effect of mixing dye in ferroelectric liquid crystal （FLC） materials, the phase transition temperature and electro-optical properties of azo dye doped FLC samples have been investigated. All the properties have been found to be changed drastically. The results have revealed that not only the SmC^＊- SmA^＊ transition temperature decreased markedly by the addition of azo-dye, but also dye-doped FLC had lower threshold voltage and saturation voltage than the pure FLC.

关键词： Azo dyes Crystallography Ferroelectric materials Ferroelectricity Light sources liquid crystals Materials properties Optical properties Superconducting transition temperature

The stress field and energy of screw dislocation in smectic A liquid crystals and the mistakes of the classical solution

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第4期23卷 422-426页

作者：范天佑李显方 School of Physics Beijing Institute of Technology Department of Engineering Mechanics Central South University

The mistakes in the classical solution of a screw dislocation in smectic A liquid crystals are pointed out. A serious problem with the well-known theory is pointed, which may be named de Gennes-Kleman-Pershan paradox and has existed for many decades in the scientific community of liquid crystal study. The correct solution is given in this paper by a simplest, elementary, and straight forward method. In connection with this, the stress field and energy of dislocation are discussed in detail. The present article provides the correct stress field and dislocation energy as well.

关键词： liquid crystals dislocation exact solution

Amide as Terminal Groups： Synthesis and Properties as New Tolane-Type liquid crystals

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2015年第7期33卷 771-776页

作者： Hong Zhang Fengying Hong Dezhao Zhu Zhengce Xia Hongxiang Wu Hui Wang Zhuo Zeng College of Chemistry & Environment South China Normal University Guangzhou Guangdong 510006 China Key Laboratory of Organofluorine Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China

A series of novel tolane-type liquid crystals with amide group as terminal group have been prepared. The terminal amide groups were modified, and the influence of these structural parameters on liquid crystal phases was investigated by polarizing optical microscope （POM） and differential scanning calorimetry （DSC）. Three of these new compounds exhibit nematic phase, good thermal stabilities. In general, these liquid crystals with amide as end groups have high melting points and phase transition temperatures, which result from the hydrogen bonds. Based on theoretical calculations, these new molecules with strong electron donating amide as end group have narrower HOMO-LUMO energy gap and higher dipole moment than tolane.

关键词： amides liquid crystals mesophase phase transition

Topological Structure of Knotted Vortex Lines in liquid crystals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2007年第6期47卷 1129-1134页

作者： DUAN Yi-Shi ZHAO Li ZHANG Xin-Hui Institute of Theoretical Physics Lanzhou University Lanzhou 730000 China

In this paper, a novel decomposition expression for the U（1） gauge field in liquid crystals （LCs） is derived. Using this decomposition expression and the b-mapping topological current theory, we investigate the topological structure of the vortex lines in LCs in detail. A topological invariant, i.e., the Chern-Simons （CS） action for the knotted vortex lines is presented, and the CS action is shown to be the total sum of all the self-linking and linking numbers of the knot family. Moreover, it is pointed out that the CS action is preserved in the branch processes of the knotted vortex lines.

关键词： knotted vortex lines liquid crystals Chern-Simons action branch processes

ON GLOBAL BEHAVIOR OF WEAK SOLUTIONS OF COMPRESSIBLE FLOWS OF NEMATIC liquid crystals

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2015年第3期35卷 650-672页

作者：王伟伟 College of Mathematics and Computer Science Fuzhou University

In this article, we investigate the global behavior of weak solutions of a simplified Ericksen-Leslie system for compressible flows of nematic liquid crystals in time in a bounded three-dimension domain-arbitrary forces. By adapting the arguments for the compressible Navier-Stokes equations, and carefully analyzing the direction field of liquid crystals in the equations of angular momentum, we show the existence of bounded absorbing sets, global bounded trajectories, and global attractors to weak solutions of compressible flows of nematic liquid crystals with the adiabatic constant γ〉5/3.

关键词： liquid crystals weak solutions bounded absorbing set bounded trajectories attractor