Investigation of transient photoresponse of WSSe ternary alloy crystals

Science.gov (United States)

Chauhan, Payal; Solanki, G. K.; Tannarana, Mohit; Pataniya, Pratik; Patel, K. D.; Pathak, V. M.

2018-05-01

Transition metal chalcogenides have been studied intensively in recent time due to their tunability of electronic properties by compositional change, alloying and by transforming bulk material into crystalline 2D structure. These changes lead to the development of verities of next generation opto-electronic device applications such as solar cells, FETs and flexible detectors etc. In present work, we report growth and characterization of crystalline ternary alloy WSSe by direct vapour transport technique. A photodetector is constructed using grown crystals to study its transient photoresponse under polychromatic radiation. The WSSe crystals are mechanically exfoliated to thickness of 3 µm and the lateral dimension of prepared sample is 2.25 mm2. The time-resolved photoresponse is studied under polychromatic illumination of power density ranging from 10 to 40 mW/cm2. The photo response is also studied under different bias voltages ranging from 0.1 V to 0.5 V. The typical photodetector parameters i.e. photocurrent, rise and fall time, responsivity and sensitivity are evaluated and discussed in light of the ternary alloy composition.

Ternary chalcopyrite semiconductors

CERN Document Server

Shay, J L; Pamplin, B R

2013-01-01

Ternary Chalcopyrite Semiconductors: Growth, Electronic Properties, and Applications covers the developments of work in the I-III-VI2 and II-IV-V2 ternary chalcopyrite compounds. This book is composed of eight chapters that focus on the crystal growth, characterization, and applications of these compounds to optical communications systems. After briefly dealing with the status of ternary chalcopyrite compounds, this book goes on describing the crystal growth of II-IV-V2 and I-III-VI2 single crystals. Chapters 3 and 4 examine the energy band structure of these semiconductor compounds, illustrat

Ternary fission in an effective liquid drop model

International Nuclear Information System (INIS)

Duarte, Sergio B.; Tavares, Odilon A.P.; Dimarco, A.; Goncalves, Marcello; Guzman, Fernando; Trallero-Herrera, Carlos; Rodriguez, Oscar; Garcia, Fermin

2001-01-01

Full text follows: The nuclear partition in three fragments has been observed in recent experiments for fission process of 252 Cf and 24 '0 Pu. We apply the Effective Liquid Drop Model (ELDM), successfully used for discussing binary cold fission and cluster emissions for a three center geometric shape parametrization, describing the quasi-molecular deformation which can lead to ternary fragmentation. A preliminary calculation for rates of these processes are performed and the results are compared to the rate of the dominant binary fission process. A large range of parent nuclei (spherical and deformed) is covered in the calculation. The purpose is to point out others possible ternary fission process experimentally measurable. (author)

Thermodynamic modeling of ternary and quaternary (liquid + liquid) systems containing water, FeCl3, HCl and diisopropyl ether

International Nuclear Information System (INIS)

Milosevic, Miran; Hendriks, Ilse; Smits, Ralph E.R.; Schuur, Boelo; Haan, André B. de

2013-01-01

Highlights: • Literature data from various sources was validated experimentally. • Ternary and quaternary (liquid + liquid) systems were successfully described with the NRTL model. • Some deflection at higher HCl concentrations between model and data. • Additional data verification proved correctness of the literature data. -- Abstract: Liquid–liquid extraction using ethers as solvents is a potentially energy saving alternative for the concentration of aqueous ferric chloride solutions. Adequate thermodynamic models that describe the behavior of the resulting quaternary systems (FeCl 3 , ether, acid and water) are not available in the literature. In this paper, the development of an equilibrium description applying the NRTL-model is presented, including experimental validation and fitting of the NRTL-parameters on the validated data. Equilibrium experiments were performed for the ternary systems (water + HCl + DiPE) and (water + FeCl 3 + DiPE) and the obtained data is in good agreement with the results from Maljkovic et al.[37] and Cambell et al.[39]. Experimental data of the quaternary system is taken from Maljkovic et al.[37]. The obtained binary interaction parameters to describe the (liquid + liquid) quaternary system (water + FeCl 3 + HCl + DiPE) and the constituting ternaries by the NRTL model are presented. Model predictions are in good agreement with the experimental data

Prediction of (liquid + liquid) equilibrium for binary and ternary systems containing ionic liquids with the bis[(trifluoromethyl)sulfonyl]imide anion using the ASOG method

International Nuclear Information System (INIS)

Robles, Pedro A.; Cisternas, Luis A.

2015-01-01

Highlights: • ASOG model was used to predict LLE data for ionic liquid systems. • Twenty five binary and seven ternary systems that include the NTf 2 anion were used. • New group interaction parameters were determined. • The results are satisfactory, with rms deviations of about 3%. - Abstract: Ionic liquids are neoteric, environmentally friendly solvents (as they do not produce emissions) composed of large organic cations and relatively small inorganic anions. They have favorable physical properties, such as negligible volatility and a wide range of liquid existence. (Liquid + liquid) equilibrium (LLE) data for systems including ionic liquids, although essential for the design, optimization and operation of separation processes, remain scarce. However, some recent studies have presented ternary LLE data involving several ionic liquids and organic compounds such as alkanes, alkenes, alkanols, ethers and aromatics, as well as water. In this work, the ASOG model for the activity coefficient is used to predict LLE data for 25 binary and 07 ternary systems at 101.3 kPa and several temperatures; all the systems are formed by ionic liquids including the bis[(trifluoromethyl)sulfonyl]imide (NTf 2 ) anion plus alkanes, alkenes, cycloalkanes, alkanols, water, thiophene and aromatics. New group interaction parameters were determined using a modified Simplex method, minimizing a composition-based objective function of experimental data obtained from the literature. The results are satisfactory, with rms deviations of approximately 3%

Phase equilibria in M-X-X' and M-Al-X ternary systems (M-transition metal, X,X'-B,C,N,Si) and crystal chemistry of ternary compounds

International Nuclear Information System (INIS)

Gusev, A.I.

1996-01-01

The data on phase equilibria in the M-X-X' and M-Al-X ternary systems (M-transition metal of 3 to 8 groups, X-B,C, N, Si) have been considered and summarized. modern oxygen-free advanced ceramics is based on these ternary systems. Phase diagrams of the 130 ternary systems have been discussed, more than two hundred ternary phases forming in these systems have been systematized and described. The typical crystal structures of ternary compounds and phase have been considered, the common and distinctive features of these structures have been analysed. It has been shown that the ternary compounds with octahedral atomic groups XM 6 have a regions of homogeneity. Refs. 240

Omnidirectional reflection in one-dimensional ternary photonic crystals and photonic heterostructures

Energy Technology Data Exchange (ETDEWEB)

Wang, Shiqi [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Yang, Xiangbo, E-mail: 20001038@m.scnu.edu.cn [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006 (China); Liu, Chengyi Timon [School of Physical Education and Sports Science, South China Normal University, Guangzhou 510006 (China)

2014-03-01

Designing dielectric systems to create omnidirectional band gaps (OBGs) is an attractive topic in the field of photonic band gap (PBG) structures. In this Letter, we propose a new approach to create OBGs by ternary photonic heterostructures (TPHs) composed of three kinds of materials with different refractive indices and obtain the formulae of the structures of TPHs, i.e., those of the thicknesses of materials and the number of sub-ternary photonic crystals. It may provide a powerful technique for designing the structures being able to produce OBGs by use of usual materials, lowcost materials, and materials with low refractive indices, etc.

Omnidirectional reflection in one-dimensional ternary photonic crystals and photonic heterostructures

International Nuclear Information System (INIS)

Wang, Shiqi; Yang, Xiangbo; Liu, Chengyi Timon

2014-01-01

Designing dielectric systems to create omnidirectional band gaps (OBGs) is an attractive topic in the field of photonic band gap (PBG) structures. In this Letter, we propose a new approach to create OBGs by ternary photonic heterostructures (TPHs) composed of three kinds of materials with different refractive indices and obtain the formulae of the structures of TPHs, i.e., those of the thicknesses of materials and the number of sub-ternary photonic crystals. It may provide a powerful technique for designing the structures being able to produce OBGs by use of usual materials, lowcost materials, and materials with low refractive indices, etc.

Studies on Molecular Interaction in Ternary Liquid Mixtures

Directory of Open Access Journals (Sweden)

R. Uvarani

2010-01-01

Full Text Available Ultrasonic velocity, density and viscosity for the ternary liquid mixtures of cyclohexanone with 1-propanol and 1-butanol in carbon tetrachloride were measured at 303 K. The acoustical parameters and their excess values were calculated. The trends in the variation of these excess parameters were used to discuss the nature and strength of the interactions present between the component molecules.

Solid-Liquid and Liquid-Liquid Equilibrium in the Ternary System Acetic Acid-Propanoic Acid-Formamide.

Czech Academy of Sciences Publication Activity Database

Sedláková, Zuzana; Malijevská, I.

2007-01-01

Roč. 261, 1-2 (2007) , s. 129-132 ISSN 0378-3812. [International Conference on Properties and Phase Equilibria for Product and Process Design PPEPPD 2007 /11./. Hersonissos, Crete, 20.05.2007-25.05.2007] Institutional research plan: CEZ:AV0Z40720504 Keywords : solid-liquid equilibrium * ternary system * solid adduct Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.506, year: 2007

(Liquid + liquid) equilibrium at T = 298.15 K for ternary mixtures of alkane + aromatic compounds + imidazolium-based ionic liquids

International Nuclear Information System (INIS)

Domínguez, Irene; Requejo, Patricia F.; Canosa, José; Domínguez, Ángeles

2014-01-01

Highlights: • The LLE ternary phase diagrams with 2 imidazolium-based ionic liquids were measured. • The LLE data were experimental determined at T = 298.15 K and p = 1 atm. • Mixtures of (octane or nonane) and (benzene or toluene or ethylbenzene) were studied. • LLE experimental data were correlated with NRTL and UNIQUAC thermodynamic models. - Abstract: Ionic liquids, with their unique and tunable properties, can be an advantageous alternative as extractive solvents in separation processes involving systems containing aliphatic and aromatic hydrocarbons. In this work, (liquid + liquid) equilibrium (LLE) data for the ternary systems {nonane (1) + benzene (2) + 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [BMim][NTf 2 ] (3)}, {octane (1) + benzene (2) + 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide, [PMim][NTf 2 ] (3)}, and {nonane (1) + aromatic compound (benzene or toluene or ethylbenzene) (2) + [PMim][NTf 2 ] (3)} were determined at T = 298.15 K and atmospheric pressure. Selectivity and solute distribution ratio, derived from the equilibrium data, were used to determine if this ionic liquid can be considered as a potential solvent for the separation of aromatic compounds (benzene, toluene, and ethylbenzene) from alkanes (octane and nonane). The experimental data were satisfactorily correlated with NRTL and UNIQUAC models

Enhanced thermal lens effect in gold nanoparticle-doped Lyotropic liquid crystal by nanoparticle clustering probed by Z-scan technique

International Nuclear Information System (INIS)

Gomez, S.L.; Lenart, V.M.

2015-01-01

This work presents an experimental study of the thermal lens effect in Au nanoparticles-doped lyotropic liquid crystals under cw 532 nm optical excitation. Spherical Au nanoparticles of about 12 nm were prepared by Turkevich’s method, and the lyotropic liquid crystal was a ternary mixture of SDS, 1-DeOH, and water that exhibits an isotropic phase at room temperature. The lyotropic matrix induces aggregation of the nanoparticles, leading to a broad and a red-shifted surface plasmon resonance. The thermal nonlinear optical refraction coefficient n 2 increases as a power of number density of nanoparticles, being possible to address this behavior to nanoparticle clustering. (author)

Enhanced thermal lens effect in gold nanoparticle-doped Lyotropic liquid crystal by nanoparticle clustering probed by Z-scan technique

Energy Technology Data Exchange (ETDEWEB)

Gomez, S.L.; Lenart, V.M., E-mail: sgomez@uepg.br [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil). Dept. de Fisica; Turchiello, R.T. [Universidade Federal Tecnologica do Parana (UFTPR), Ponta Grossa, PR (Brazil). Dept. de Fisica; Goya, G.F. [Department of Condensed Matter Physics, Aragon Institute of Nanoscience, Zaragoza (Spain)

2015-10-01

This work presents an experimental study of the thermal lens effect in Au nanoparticles-doped lyotropic liquid crystals under cw 532 nm optical excitation. Spherical Au nanoparticles of about 12 nm were prepared by Turkevich’s method, and the lyotropic liquid crystal was a ternary mixture of SDS, 1-DeOH, and water that exhibits an isotropic phase at room temperature. The lyotropic matrix induces aggregation of the nanoparticles, leading to a broad and a red-shifted surface plasmon resonance. The thermal nonlinear optical refraction coefficient n{sub 2} increases as a power of number density of nanoparticles, being possible to address this behavior to nanoparticle clustering. (author)

(Liquid + liquid) equilibria of (water + linalool + limonene) ternary system at T = (298.15, 308.15, and 318.15) K

International Nuclear Information System (INIS)

Gramajo de Doz, Monica B.; Cases, Alicia M.; Solimo, Horacio N.

2008-01-01

(Liquid + liquid) equilibrium (LLE) data for {water (1) + linalool (2) + limonene (3)} ternary system at T = (298.15, 308.15, and 318.15 ± 0.05) K are reported. The organic chemicals were quantified by gas chromatography using a flame ionisation detector while water was quantified using a thermal conductivity detector. The effect of the temperature on (liquid + liquid) equilibrium is determined and discussed. Experimental data for the ternary mixture are compared with values calculated by the NRTL and UNIQUAC equations, and predicted by means of the UNIFAC group contribution method. It is found that the UNIQUAC and NRTL models provide a good correlation of the solubility curve at these three temperatures, while comparing the calculated values with the experimental ones, the best fit is obtained with the NRTL model. Finally, the UNIFAC model provides poor results, since it predicts a greater heterogeneous region than experimentally observed

(Vapour + liquid) equilibria of ternary systems with ionic liquids using headspace gas chromatography

International Nuclear Information System (INIS)

Mokhtarani, Babak; Gmehling, Juergen

2010-01-01

(Vapour + liquid) equilibrium (VLE) data for the ternary systems (hexane + benzene), (hexane + cyclohexane), (benzene + cyclohexane), and (ethanol + water) with an ionic liquid as entrainer for extractive distillation were measured by headspace gas chromatography. As ionic liquids, 1-hexyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [HMIM][BTI], 1-octyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [OMIM][BTI], 1-octyl-3-methyl-imidazolium trifluoro-methanesulfonate [OMIM][OTF], and 1-butyl-3-methyl-imidazolium trifluoro-methanesulfonate [BMIM][OTF] were used. The experimental data show that the ionic liquids investigated have a great influence on the separation factors of the systems (hexane + benzene), (hexane + cyclohexane), and (benzene + cyclohexane). The experimental data were compared with the predicted results using mod. UNIFAC (Do). The predicted results are in good agreement with the experimental data.

(Vapour + liquid) equilibria of ternary systems with ionic liquids using headspace gas chromatography

Energy Technology Data Exchange (ETDEWEB)

Mokhtarani, Babak [Chemistry and Chemical Engineering Research Center of Iran, P.O. Box 14335-186, Tehran (Iran, Islamic Republic of); Gmehling, Juergen, E-mail: gmehling@tech.chem.uni-oldenburg.d [Carl von Ossietzky Universitaet Oldenburg, Technische Chemie, D-26111 Oldenburg (Germany)

2010-08-15

(Vapour + liquid) equilibrium (VLE) data for the ternary systems (hexane + benzene), (hexane + cyclohexane), (benzene + cyclohexane), and (ethanol + water) with an ionic liquid as entrainer for extractive distillation were measured by headspace gas chromatography. As ionic liquids, 1-hexyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [HMIM][BTI], 1-octyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [OMIM][BTI], 1-octyl-3-methyl-imidazolium trifluoro-methanesulfonate [OMIM][OTF], and 1-butyl-3-methyl-imidazolium trifluoro-methanesulfonate [BMIM][OTF] were used. The experimental data show that the ionic liquids investigated have a great influence on the separation factors of the systems (hexane + benzene), (hexane + cyclohexane), and (benzene + cyclohexane). The experimental data were compared with the predicted results using mod. UNIFAC (Do). The predicted results are in good agreement with the experimental data.

Refractive indices of ternary liquid mixtures containing aliphatic alcohols at several temperatures

Directory of Open Access Journals (Sweden)

Sovilj Milan N.

2005-01-01

Full Text Available The refractive indices of ternary liquid mixtures (2-propanol+2-butanol+ethanol and (chloroform+2-propanol+2-butanol were measured at 20, 25, 30, and 35°C, and atmospheric pressure. The results were used to calculate the refractive index deviations over the entire mole fraction range for the mixtures. The refractive index deviations for the ternary mixtures were further fitted to empirical correlations (Cibulka Nagata-Tamura, and Lopez et al to estimate the ternary fitting parameters. Standard deviations and average percentage deviations from the regression lines are shown. The best fit was obtained by the Nagata-Tamura empirical correlation. Some of the existing predictive equations for the refractive index deviations (Tsao-Smith, Köhler, and Colinet were tested.

Liquid Crystal Colloids

Science.gov (United States)

Smalyukh, Ivan I.

2018-03-01

Colloids are abundant in nature, science, and technology, with examples ranging from milk to quantum dots and the colloidal atom paradigm. Similarly, liquid crystal ordering is important in contexts ranging from biological membranes to laboratory models of cosmic strings and liquid crystal displays in consumer devices. Some of the most exciting recent developments in both of these soft matter fields emerge at their interface, in the fast-growing research arena of liquid crystal colloids. Mesoscale self-assembly in such systems may lead to artificial materials and to structures with emergent physical behavior arising from patterning of molecular order and nano- or microparticles into precisely controlled configurations. Liquid crystal colloids show exceptional promise for new discovery that may impinge on composite material fabrication, low-dimensional topology, photonics, and so on. Starting from physical underpinnings, I review the state of the art in this fast-growing field, with a focus on its scientific and technological potential.

Experimental investigation of the Ag–Bi–I ternary system and thermodynamic properties of the ternary phases

International Nuclear Information System (INIS)

Mashadieva, Leyla F.; Aliev, Ziya S.; Shevelkov, Andrei V.; Babanly, Mahammad B.

2013-01-01

Highlights: ► The self-consistent phase diagram of the Ag–Bi–I system is constructed. ► Ag 2 BiI 5 and AgBi 2 I 7 are the only ternary phases of the system. ► Standard thermodynamic functions of formation and the standard entropies of Ag 2 BiI 5 and AgBi 2 I 7 are calculated. - Abstract: The phase equilibriums in the Ag–Bi–I ternary system and thermodynamic properties of the ternary phases were experimentally determined by using DTA and XRD techniques and EMF measurements with the Ag 4 RbI 5 solid electrolyte. According to the obtained experimental results, the polythermal sections of the ternary phase diagram, its isothermal section at 300 K as well as the projection of the liquids surface have been revised. The fields of the primary crystallization and types and coordinates of nonvariant and monovariant equilibriums were determined. The partial molar functions of silver iodide and silver in the alloys as well as the standard thermodynamic functions of formation and the standard entropies of Ag 2 BiI 5 and AgBi 2 I 7 were calculated based on EMF measurements.

Liquid-liquid equilibria for binary and ternary systems containing glycols, aromatic hydrocarbons, and water: Experimental measurements and modeling with the CPA EoS

DEFF Research Database (Denmark)

Folas, Georgios; Kontogeorgis, Georgios; Michelsen, Michael Locht

2006-01-01

Liquid-liquid equilibrium data of four binary glycol + aromatic hydrocarbon systems and three ternary systems containing water have been measured at atmospheric pressure. The measured systems are monoethylene glycol (MEG) + benzene or toluene, triethylene glycol (TEG) + benzene or toluene, MEG...... + water + benzene, MEG + water + toluene, and TEG + water + toluene. The binary systems are correlated with the Cubic-Plus-Association (CPA) equation of state while the ternary systems are predicted from interaction parameters obtained from the binary systems. Very satisfactory liquid-liquid equilibrium...... correlations are obtained for the binary systems using temperature-independent interaction parameters, while adequate predictions are achieved for multicomponent water + glycol + aromatic hydrocarbons systems when accounting for the solvation between the aromatic hydrocarbons and glycols or water....

Thermoluminescence response of a mixed ternary alkali halide crystals exposed to gamma rays

International Nuclear Information System (INIS)

Rodriguez M, R.; Perez S, R.; Vazquez P, G.; Riveros, H.; Gonzalez M, P.

2014-08-01

Ionic crystals, mainly alkali halide crystals have been the subject of intense research for a better understanding of the luminescence properties of defects induced by ionizing radiation. The defects in crystals can be produced in appreciable concentration due to elastic stresses, radiation, and addition of impurities. These defects exhibit remarkable thermoluminescence properties. This work is concerned with the Tl properties of a ternary alkali halide crystal after being irradiated with gamma and beta rays. It has been found that the Tl glow peak of the crystal follows a rule of average associated to the Tl Temperatures of the components of the mixture, similarly to the response of europium doped binary mixed crystals KCl x KBr 1-x and KBr x RbBr 1-x . (Author)

Ternary systems

International Nuclear Information System (INIS)

Kagan, D.N.; Hubberstey, P.; Barker, M.G.

1985-01-01

The paper reviews the experimental and theoretical studies carried out on multicomponent alkali metal systems. Solid-liquid phase equilibria studies are mainly concerned with the systems Na-K-Rb and Na-K-Cs, and data on the liquidus temperatures in these systems are presented. The thermodynamic properties of the ternary Na-K-Cs eutectic system have been determined experimentally, and the enthalpy, heat capacity and excess functions of the alloy are given. An analysis of calculational methods used in determining thermodynamic functions of ternary liquid metals systems is described. Finally, data are tabulated for the density, compressibility, saturated vapour pressure, viscosity and thermal conductivity of the ternary Na-K-Cs eutectic system. (UK)

Physical Properties of Liquid Crystals

CERN Document Server

Gray, George W; Spiess, Hans W

1999-01-01

This handbook is a unique compendium of knowledge on all aspects of the physics of liquid crystals. In over 500 pages it provides detailed information on the physical properties of liquid crystals as well as the recent theories and results on phase transitions, defects and textures of different types of liquid crystals. An in-depth understanding of the physical fundamentals is a prerequisite for everyone working in the field of liquid crystal research. With this book the experts as well as graduate students entering the field get all the information they need.

Liquid-liquid phase equilibria for ternary systems of several polyethers with NaCl and H2O

NARCIS (Netherlands)

Milosevic, M.; Staal, K.J.J.; Schuur, Boelo; de Haan, A.B.

2014-01-01

Liquid–liquid extraction using polymers followed by induced phase separation is a potential energy reducing technology for water–salt separation. Ternary equilibrium data have been determined and reported for the (block co)poly ethers–sodium chloride–water systems at two different temperatures at

The sweet world of liquid crystals : The synthesis of non-amphiphilic carbohydrate-derived liquid crystals

NARCIS (Netherlands)

Smits, E

1998-01-01

The research in carbohydrate-derived liquid crystals was initiated by a review article by Jeffrey in 1986. This is rather late if one considers that the research on liquid crystals underwent a revival already in the 1960s after the discovery of the liquid crystal display (LCD). Carbohydrates were

Pressure sensor using liquid crystals

Science.gov (United States)

Parmar, Devendra S. (Inventor); Holmes, Harlan K. (Inventor)

1994-01-01

A pressure sensor includes a liquid crystal positioned between transparent, electrically conductive films (18 and 20), that are biased by a voltage (V) which induces an electric field (E) that causes the liquid crystal to assume a first state of orientation. Application of pressure (P) to a flexible, transparent film (24) causes the conductive film (20) to move closer to or farther from the conductive film (18), thereby causing a change in the electric field (E'(P)) which causes the liquid crystal to assume a second state of orientation. Polarized light (P.sub.1) is directed into the liquid crystal and transmitted or reflected to an analyzer (A or 30). Changes in the state of orientation of the liquid crystal induced by applied pressure (P) result in a different light intensity being detected at the analyzer (A or 30) as a function of the applied pressure (P). In particular embodiments, the liquid crystal is present as droplets (10) in a polymer matrix (12) or in cells (14) in a polymeric or dielectric grid (16) material in the form of a layer (13) between the electrically conductive films (18 and 20). The liquid crystal fills the open wells in the polymer matrix (12) or grid (16) only partially.

Thermoluminescence response of a mixed ternary alkali halide crystals exposed to gamma rays

Energy Technology Data Exchange (ETDEWEB)

Rodriguez M, R.; Perez S, R. [Universidad de Sonora, Departamento de Investigacion en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico); Vazquez P, G.; Riveros, H. [UNAM, Instituto de Fisica, Apdo. Postal 20-364, 01000 Mexico D. F. (Mexico); Gonzalez M, P., E-mail: mijangos@cifus.uson.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2014-08-15

Ionic crystals, mainly alkali halide crystals have been the subject of intense research for a better understanding of the luminescence properties of defects induced by ionizing radiation. The defects in crystals can be produced in appreciable concentration due to elastic stresses, radiation, and addition of impurities. These defects exhibit remarkable thermoluminescence properties. This work is concerned with the Tl properties of a ternary alkali halide crystal after being irradiated with gamma and beta rays. It has been found that the Tl glow peak of the crystal follows a rule of average associated to the Tl Temperatures of the components of the mixture, similarly to the response of europium doped binary mixed crystals KCl{sub x}KBr{sub 1-x} and KBr{sub x}RbBr{sub 1-x}. (Author)

Crystal chemistry and magnetic properties of ternary rare earth sulfides

International Nuclear Information System (INIS)

Plug, C.M.; Rijksuniversiteit Leiden

1977-01-01

The results of magnetic measurements on two groups of ternary rare earth sulphides are described, the MLnS 2 (M=Li, Na, K) type of compounds and the series Ln 2 ZrS 5 , where Ln denotes one of the rare earths. None of these compounds is metallic, excluding the possibility of RKKY-interaction. In chapter II a survey of the relevant theory on magnetic properties and crystal field splitting is given. In spite of the similarity in chemical properties of the rare earths, the crystal chemistry of their compounds is rather complex. This is due to the lanthanide contraction. The third chapter deals with the description and classification of the numerous crystal structures of both ternary and binary rare earth sulphides that have been observed. Rather simple relations between various structures are presented using a new method of structure classification. The magnetic interactions expected to be based on superexchange via the anions, which is usually very structure dependent. Experiments to study the crystallographic ordering, applying both X-ray and electron diffraction methods and the results of the magnetic measurements on the compounds MLnS 2 are reported in chapter IV. The compounds Ln 2 ZrS 5 are candidates for a systematic study of the variation of the magnetic properties along the rare earth series. The results of magnetic measurements on these compounds are presented in chapter V, combined with the results of specific heat measurements. Also the magnetic structure of two representatives, Tb 2 ZrS 5 and Dy 2 ZrS 5 , determined by neutron diffraction experiments below the ordering temperature, is reported

Modeling liquid crystal polymeric devices

Science.gov (United States)

Gimenez Pinto, Vianney Karina

The main focus of this work is the theoretical and numerical study of materials that combine liquid crystal and polymer. Liquid crystal elastomers are polymeric materials that exhibit both the ordered properties of the liquid crystals and the elastic properties of rubbers. Changing the order of the liquid crystal molecules within the polymer network can induce shape change. These materials are very valuable for applications such as actuators, sensors, artificial muscles, haptic displays, etc. In this work we apply finite element elastodynamics simulations to study the temperature induced shape deformation in nematic elastomers with complex director microstructure. In another topic, we propose a novel numerical method to model the director dynamics and microstructural evolution of three dimensional nematic and cholesteric liquid crystals. Numerical studies presented in this work are in agreement with experimental observations and provide insight into the design of application devices.

Omnidirectional photonic band gap enlarged by one-dimensional ternary unmagnetized plasma photonic crystals based on a new Fibonacci quasiperiodic structure

Energy Technology Data Exchange (ETDEWEB)

Zhang Haifeng [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Nanjing Artillery Academy, Nanjing 211132 (China); Liu Shaobin [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); State Key Laboratory of Millimeter Waves of Southeast University, Nanjing Jiangsu 210096 (China); Kong Xiangkun; Bian Borui; Dai Yi [College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

2012-11-15

In this paper, an omnidirectional photonic band gap realized by one-dimensional ternary unmagnetized plasma photonic crystals based on a new Fibonacci quasiperiodic structure, which is composed of homogeneous unmagnetized plasma and two kinds of isotropic dielectric, is theoretically studied by the transfer matrix method. It has been shown that such an omnidirectional photonic band gap originates from Bragg gap in contrast to zero-n gap or single negative (negative permittivity or negative permeability) gap, and it is insensitive to the incidence angle and the polarization of electromagnetic wave. From the numerical results, the frequency range and central frequency of omnidirectional photonic band gap can be tuned by the thickness and density of the plasma but cease to change with increasing Fibonacci order. The bandwidth of omnidirectional photonic band gap can be notably enlarged. Moreover, the plasma collision frequency has no effect on the bandwidth of omnidirectional photonic band gap. It is shown that such new structure Fibonacci quasiperiodic one-dimensional ternary plasma photonic crystals have a superior feature in the enhancement of frequency range of omnidirectional photonic band gap compared with the conventional ternary and conventional Fibonacci quasiperiodic ternary plasma photonic crystals.

Liquid Crystals in Decorative and Visual Arts

Science.gov (United States)

Makow, David

The following sections are included: * INTRODUCTION * PIGMENT AND STRUCTURAL COLOURS AND THEIR RELEVANCE TO LIQUID CRYSTALS * LIQUID CRYSTAL MATERIALS AND TECHNIQUES FOR DECORATIVE AND VISUAL ARTS * Free cholesteric liquid crystals (FCLC's) * Encapsulated liquid crystals (ECLC's) * Nonsteroid Chiral nematics * Polymers with liquid crystalline properties (PLCs) * COLOUR PROPERTIES OF CHOLESTERIC LIQUID CRYSTALS (CLC's) * Molecular structure and the mechanism of colour production * Dependence of perceived colours on the angle of illumination and viewing * Dependence of perceived colours on temperature * Additive colour properties * Methods of doubling the peak reflectance of cholesteric liquid crystals * Colour gamut * Colours of superimposed and pigmented coatings * Colours in transmission * ACKNOWLEDGEMENTS * REFERENCES

Wetting of cholesteric liquid crystals.

Science.gov (United States)

Silvestre, Nuno M; Figueirinhas Pereira, Maria Carolina; Bernardino, Nelson R; Telo da Gama, Margarida M

2016-02-01

We investigate theoretically the wetting properties of cholesteric liquid crystals at a planar substrate. If the properties of substrate and of the interface are such that the cholesteric layers are not distorted, the wetting properties are similar to those of a nematic liquid crystal. If, on the other hand, the anchoring conditions force the distortion of the liquid crystal layers the wetting properties are altered, the free cholesteric-isotropic interface is non-planar and there is a layer of topological defects close to the substrate. These deformations can either promote or hinder the wetting of the substrate by a cholesteric, depending on the properties of the cholesteric liquid crystal.

Time-Resolved Soft X-ray Diffraction Reveals Transient Structural Distortions of Ternary Liquid Crystals

Directory of Open Access Journals (Sweden)

Klaus Mann

2009-11-01

Full Text Available Home-based soft X-ray time-resolved scattering experiments with nanosecond time resolution (10 ns and nanometer spatial resolution were carried out at a table top soft X-ray plasma source (2.2–5.2 nm. The investigated system was the lyotropic liquid crystal C16E7/paraffin/glycerol/formamide/IR 5. Usually, major changes in physical, chemical, and/or optical properties of the sample occur as a result of structural changes and shrinking morphology. Here, these effects occur as a consequence of the energy absorption in the sample upon optical laser excitation in the IR regime. The liquid crystal shows changes in the structural response within few hundred nanoseconds showing a time decay of 182 ns. A decrease of the Bragg peak diffracted intensity of 30% and a coherent macroscopic movement of the Bragg reflection are found as a response to the optical pump. The Bragg reflection movement is established to be isotropic and diffusion controlled (1 μs. Structural processes are analyzed in the Patterson analysis framework of the time-varying diffraction peaks revealing that the inter-lamellar distance increases by 2.7 Å resulting in an elongation of the coherently expanding lamella crystallite. The present studies emphasize the possibility of applying TR-SXRD techniques for studying the mechanical dynamics of nanosystems.

Description of the ternary system Cu-Ge-Te

International Nuclear Information System (INIS)

Dogguy, M.; Carcaly, C.; Rivet, J.; Flahaut, J.

1977-01-01

The Cu-Ge-Te ternary system has been studied by DTA and by crystallographic and metallographic analysis. The existence of a ternary compound Cu 2 GeTe 3 is demonstrated; this compound has a ternary incongruent melting point at 500 0 C. This ternary compound has a superstructure of a zinc blende type. The study shows the existence of five ternary eutectics. Two liquid-liquid miscibility gaps exist: the first is situated entirely in the ternary system; the second gives a monotectic region within the ternary system. (Auth.)

Organic alloy systems suitable for the investigation of regular binary and ternary eutectic growth

Science.gov (United States)

Sturz, L.; Witusiewicz, V. T.; Hecht, U.; Rex, S.

2004-09-01

Transparent organic alloys showing a plastic crystal phase were investigated experimentally using differential scanning calorimetry and directional solidification with respect to find a suitable model system for regular ternary eutectic growth. The temperature, enthalpy and entropy of phase transitions have been determined for a number of pure substances. A distinction of substances with and without plastic crystal phases was made from their entropy of melting. Binary phase diagrams were determined for selected plastic crystal alloys with the aim to identify eutectic reactions. Examples for lamellar and rod-like eutectic solidification microstructures in binary systems are given. The system (D)Camphor-Neopentylglycol-Succinonitrile is identified as a system that exhibits, among others, univariant and a nonvariant eutectic reaction. The ternary eutectic alloy close to the nonvariant eutectic composition solidifies with a partially faceted solid-liquid interface. However, by adding a small amount of Amino-Methyl-Propanediol (AMPD), the temperature of the nonvariant eutectic reaction and of the solid state transformation from plastic to crystalline state are shifted such, that regular eutectic growth with three distinct nonfaceted phases is observed in univariant eutectic reaction for the first time. The ternary phase diagram and examples for eutectic microstructures in the ternary and the quaternary eutectic alloy are given.

Experimental and predicted refractive index properties in ternary mixtures of associated liquids

International Nuclear Information System (INIS)

Sechenyh, Vitaliy V.; Legros, Jean-Claude; Shevtsova, Valentina

2011-01-01

Highlights: → Measurements of refractive indices of 200 different aqueous ternary mixtures have been performed for two wave lengths. → Refractive indices of the associated ternary mixtures can be modeled with a relative error of about 0.9. → Difference between experimental and calculated derivatives of refractive index with concentration is unsatisfactory large. - Abstract: Refractive indices of ternary mixtures formed by (water + ethanol + k-ethylene glycol) (when k is mono, di or tri) and (water + t-butanol + dimethyl sulfoxide) are presented over a wide range of mixture compositions. All measurements have been conducted at 298.15 K and atmospheric pressure using two light sources: one in the visible (λ = 670 nm) and the other in the infrared (λ = 925 nm) spectrum. The performance of several mixing rules that are commonly used in modeling optical constants are examined. We demonstrate that the refractive indices of the associated ternary mixtures can be modeled with a relative error of about 0.9% by using the thermodynamical properties of the pure components. The concentration derivatives of the refractive index are an important parameter, as they are required for different experimental techniques. These derivatives have been determined from the experimental data on refractive indices. However, applying mixing rules for calculation of the derivatives of the refractive indices with respect to concentrations does not provide satisfactory results in the case of ternary mixtures of associated liquids.

Binary and ternary (liquid + liquid) equilibrium for {methylcyclohexane (1) + toluene (2) + 1-hexyl-3-methylimidazolium tetracyanoborate (3)/1-butyl-3-methylimidazolium tetracyanoborate (3)}

International Nuclear Information System (INIS)

Gutierrez, Juan Pablo; Meindersma, Wytze; Haan, Andre B. de

2011-01-01

Highlights: → Binary and ternary extractions for two ionic liquids with organic compounds were measured. → NRTL and UNIQUAC thermodynamic models were used to fit the experimental data. → UNIQUAC model gives better predictions than the NRTL model. → Ionic liquids showed interesting properties as solvents to be applied in separation processes. - Abstract: This paper focuses on the study of the solubility behaviour of 1-hexyl-3-methylimidazolium tetracyanoborate [HMIM][TCB] and 1-butyl-3-methylimidazolium tetracyanoborate [BMIM][TCB] in combination with methylcyclohexane and toluene as representatives for non-aromatic and aromatic components. Binary and ternary (liquid + liquid) equilibrium data were collected at three different temperatures and at atmospheric pressure (0.1 MPa). The experimental data were well-correlated with the NRTL and UNIQUAC thermodynamic models; however, the UNIQUAC model gave better predictions than the NRTL, with a root mean square error below 0.97%. The non-aromatic/aromatic selectivities of the ionic liquids make them suitable solvents to be used in extractive distillation processes.

Calculation of liquid-liquid phase separation in a ternary system of a polymer in a mixture of a solvent and a nonsolvent

NARCIS (Netherlands)

Altena, Frank W.; Smolders, C.A.

1982-01-01

A numerical method for the calculation of the binodal of liquid-liquid phase separation in a ternary system is described. The Flory-Huggins theory for three-component systems is used. Binodals are calculated for polymer/solvent/nonsolvent systems which are used in the preparation of asymmetric

Crystal Growth of ZnSe and Related Ternary Compound Semiconductors by Vapor Transport in Low Gravity

Science.gov (United States)

Su, Ching-Hua; Ramachandran, N.

2013-01-01

Crystals of ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, will be grown by physical vapor transport in the Material Science Research Rack (MSRR) on International Space Station (ISS). The objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the crystals grown by vapor transport as results of buoyance-driven convection and growth interface fluctuations caused by irregular fluid-flows on Earth. The investigation consists of extensive ground-based experimental and theoretical research efforts and concurrent flight experimentation. The objectives of the ground-based studies are (1) obtain the experimental data and conduct the analyses required to define the optimum growth parameters for the flight experiments, (2) perfect various characterization techniques to establish the standard procedure for material characterization, (3) quantitatively establish the characteristics of the crystals grown on Earth as a basis for subsequent comparative evaluations of the crystals grown in a low-gravity environment and (4) develop theoretical and analytical methods required for such evaluations. ZnSe and related ternary compounds have been grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals have been characterized extensively by various techniques to correlate the grown crystal properties with the growth conditions.

Crystallization processes in Ni-Ti-B glassy alloys of near-ternary-eutectic composition

International Nuclear Information System (INIS)

Merk, N.; Morris, D.G.; Stadelmann, P.

1987-01-01

The crystallization kinetics and mechanisms of three Ni-Ti-B glasses have been examined with a view to elucidating the roles of chemical composition and quenched structure on behaviour. Alloys of composition near a ternary-eutectic point have been chosen because they represent a real and complex situation where several crystalline phases may form simultaneously. Crystallization processes are analysed in terms of nucleation and growth stages. Different nucleation mechanisms seem to be best explained in terms of the short range ordered structure of the quenched glass. Analysis of crystal glass interface energies indicates that it is not this energy term which controls the nucleation of crystals on annealing. Crystal growth may involve a eutectic mechanism or a single-phase mechanism controlled by interface or matrix-diffusion kinetics. Crystallization is fastest when eutectic nucleation and growth occurs. Formation of the eutectic colony requires the initial formation of the phase of complex structure followed by the phase of simpler structure

Phase composition and saturated liquid properties in binary and ternary systems containing carbon dioxide, n-decane, and n-tetradecane

International Nuclear Information System (INIS)

Kariznovi, Mohammad; Nourozieh, Hossein; Abedi, Jalal

2013-01-01

Highlights: ► Binary and ternary systems of (carbon dioxide + n-decane + n-tetradecane) at 323.2 K. ► Isothermal phase properties measurements over wide range of pressure (1 to 6) MPa. ► Experimental measurements, density, viscosity, and composition, using a designed PVT apparatus. ► The experimental data were correlated using two equations of state. ► The interaction parameters and the volume shift values from the experimental data on the binary pairs. - Abstract: Experimental phase equilibrium data have been measured for the binary and ternary systems containing (carbon dioxide, n-decane, and n-tetradecane) at 323.2 K over the pressure range (1 to 6) MPa using a designed PVT apparatus. The measurements presented in this paper were undertaken to determine liquid phase composition and liquid saturated properties (density and viscosity) when a liquid hydrocarbon (n-decane, n-tetradecane, and their mixtures) was saturated with carbon dioxide. The generated data for compositions and densities were correlated with the Soave–Redlich–Kwong (SRK) and Peng–Robinson (PR) equations of state (EOS). The adjustment of binary interaction parameters and volume translation technique has been employed to correlate the experimental compositions and densities. The adjusted binary parameters from the data of binary pairs (carbon dioxide + n-decane) and (carbon dioxide + n-tetradecane) were used to correlate the generated ternary data. The calculated ternary compositions were found to be in good agreement with the experimental data using the binary parameters from the data of binary pairs for both EOSs. The results for the density of saturated liquid phase indicated that the volume translation should be applied to all components in the binary and ternary systems to describe accurately the saturated liquid densities for mixtures.

Liquid crystal interfaces: Experiments, simulations and biosensors

Science.gov (United States)

Popov, Piotr

Interfacial phenomena are ubiquitous and extremely important in various aspects of biological and industrial processes. For example, many liquid crystal applications start by alignment with a surface. The underlying mechanisms of the molecular organization of liquid crystals at an interface are still under intensive study and continue to be important to the display industry in order to develop better and/or new display technology. My dissertation research has been devoted to studying how complex liquid crystals can be guided to organize at an interface, and to using my findings to develop practical applications. Specifically, I have been working on developing biosensors using liquid-crystal/surfactant/lipid/protein interactions as well as the alignment of low-symmetry liquid crystals for potential new display and optomechanical applications. The biotechnology industry needs better ways of sensing biomaterials and identifying various nanoscale events at biological interfaces and in aqueous solutions. Sensors in which the recognition material is a liquid crystal naturally connects the existing knowledge and experience of the display and biotechnology industries together with surface and soft matter sciences. This dissertation thus mainly focuses on the delicate phenomena that happen at liquid interfaces. In the introduction, I start by defining the interface and discuss its structure and the relevant interfacial forces. I then introduce the general characteristics of biosensors and, in particular, describe the design of biosensors that employ liquid crystal/aqueous solution interfaces. I further describe the basic properties of liquid crystal materials that are relevant for liquid crystal-based biosensing applications. In CHAPTER 2, I describe the simulation methods and experimental techniques used in this dissertation. In CHAPTER 3 and CHAPTER 4, I present my computer simulation work. CHAPTER 3 presents insight of how liquid crystal molecules are aligned by

Thermotropic Ionic Liquid Crystals

Science.gov (United States)

Axenov, Kirill V.; Laschat, Sabine

2011-01-01

The last five years’ achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed. PMID:28879986

Thermotropic Ionic Liquid Crystals

Directory of Open Access Journals (Sweden)

Sabine Laschat

2011-01-01

Full Text Available The last five years’ achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed.

Thermotropic Ionic Liquid Crystals.

Science.gov (United States)

Axenov, Kirill V; Laschat, Sabine

2011-01-14

The last five years' achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed.

Thermotropic Ionic Liquid Crystals

OpenAIRE

Axenov, Kirill V.; Laschat, Sabine

2011-01-01

The last five years’ achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed.

Nonlinear and quantum optics with liquid crystals

International Nuclear Information System (INIS)

Lukishova, Svetlana G

2014-01-01

Thermotropic liquid crystals' usual application is display technology. This paper describes experiments on light interaction with pure and doped liquid crystals under for these materials unconventional incident light powers: (1) under high-power laser irradiation, and (2) at the single-photon level. In (1), I will outline several nonlinear optical effects under high-power, nanosecond laser irradiation which should be taken into account in the design of lasers with liquid crystal components and in fabrication of optical power limiters based on liquid crystals: (1.1) athermal helical pitch dilation and unwinding of cholesteric mirrors (both in free space and inside laser resonators); (1.2) some pitfalls in measurements of refractive nonlinearity using z-scan technique under two-photon or linear absorption of liquids; (1.3) the first observation of thermal lens effects in liquid crystals under several-nanosecond, low-pulse-repetition rate (2-10 Hz) laser irradiation in the presence of two-photon absorption; (1.4) feedback-free kaleidoscope of patterns (hexagons, stripes, etc.) in dye-doped liquid crystals. In (2), at the single-photon level, it will be shown that with a proper selection of liquid crystals and a single-emitter dopant spectral range, liquid crystal structures can be used to control emitted single photons (both polarization and count rate). The application of the latter research is absolutely secure quantum communication with polarization coding of information. In particular, in (2.1), definite handedness, circular polarized cholesteric microcavity resonance in quantum dot fluorescence is reported. In (2.2), definite linear polarization of single (antibunched) photons from single-dye-molecules in planar-aligned nematic host is discussed. In (2.3), some results on photon antibunching from NV-color center in nanodiamond in liquid crystal host and circularly polarized fluorescence of definite handedness from nanocrystals doped with trivalent ions of

Key Developments in Ionic Liquid Crystals

OpenAIRE

Fernandez, A.A.; Kouwer, P.H.J.

2016-01-01

Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a...

Lyotropic Liquid Crystal Phases from Anisotropic Nanomaterials

Directory of Open Access Journals (Sweden)

Ingo Dierking

2017-10-01

Full Text Available Liquid crystals are an integral part of a mature display technology, also establishing themselves in other applications, such as spatial light modulators, telecommunication technology, photonics, or sensors, just to name a few of the non-display applications. In recent years, there has been an increasing trend to add various nanomaterials to liquid crystals, which is motivated by several aspects of materials development. (i addition of nanomaterials can change and thus tune the properties of the liquid crystal; (ii novel functionalities can be added to the liquid crystal; and (iii the self-organization of the liquid crystalline state can be exploited to template ordered structures or to transfer order onto dispersed nanomaterials. Much of the research effort has been concentrated on thermotropic systems, which change order as a function of temperature. Here we review the other side of the medal, the formation and properties of ordered, anisotropic fluid phases, liquid crystals, by addition of shape-anisotropic nanomaterials to isotropic liquids. Several classes of materials will be discussed, inorganic and mineral liquid crystals, viruses, nanotubes and nanorods, as well as graphene oxide.

Ternary gradient metal-organic frameworks.

Science.gov (United States)

Liu, Chong; Rosi, Nathaniel L

2017-09-08

Gradient MOFs contain directional gradients of either structure or functionality. We have successfully prepared two ternary gradient MOFs based on bMOF-100 analogues, namely bMOF-100/102/106 and bMOF-110/100/102, via cascade ligand exchange reactions. The cubic unit cell parameter discrepancy within an individual ternary gradient MOF crystal is as large as ∼1 nm, demonstrating the impressive compatibility and flexibility of the component MOF materials. Because of the presence of a continuum of unit cells, the pore diameters within individual crystals also change in a gradient fashion from ∼2.5 nm to ∼3.0 nm for bMOF-100/102/106, and from ∼2.2 nm to ∼2.7 nm for bMOF-110/100/102, indicating significant porosity gradients. Like previously reported binary gradient MOFs, the composition of the ternary gradient MOFs can be easily controlled by adjusting the reaction conditions. Finally, X-ray diffraction and microspectrophotometry were used to analyse fractured gradient MOF crystals by comparing unit cell parameters and absorbance spectra at different locations, thus revealing the profile of heterogeneity (i.e. gradient distribution of properties) and further confirming the formation of ternary gradient MOFs.

Nanoscopic Manipulation and Imaging of Liquid Crystals

Energy Technology Data Exchange (ETDEWEB)

Rosenblatt, Charles S. [Case Western Reserve Univ., Cleveland, OH (United States)

2014-02-04

This is the final project report. The project’s goals centered on nanoscopic imaging and control of liquid crystals and surfaces. We developed and refined techniques to control liquid crystal orientation at surfaces with resolution as small as 25 nm, we developed an optical imaging technique that we call Optical Nanotomography that allows us to obtain images inside liquid crystal films with resolution of 60 x 60 x 1 nm, and we opened new thrust areas related to chirality and to liquid crystal/colloid composites.

Study of absorption and re-emission processes in a ternary liquid scintillation system

International Nuclear Information System (INIS)

Xiao Hualin; Wang Naiyan; Li Xiaobo; Cao Jun; Wen Liangjian; Zheng Dong

2010-01-01

Liquid scintillators are widely used as the neutrino target in neutrino experiments. The absorption and emission of different components of a ternary liquid scintillator (Linear Alkyl Benzene (LAB) as the solvent, 2, 5-diphenyloxazole (PPO) as the fluor and p-bis-(o-methylstyryl)-benzene (bis-MSB) as wavelength shifter) are studied. It is shown that the absorption of this liquid scintillator is dominant by LAB and PPO at wavelengths less than 349 nm, and the absorption by bis-MSB becomes prevalent at the wavelength larger than 349 nm. The fluorescence quantum yields, which are the key parameters to model the absorption and re-emission processes in large liquid scintillation detectors, are measured. (authors)

Construction of Lines of Constant Density and Constant Refractive Index for Ternary Liquid Mixtures.

Science.gov (United States)

Tasic, Aleksandar Z.; Djordjevic, Bojan D.

1983-01-01

Demonstrates construction of density constant and refractive index constant lines in triangular coordinate system on basis of systematic experimental determinations of density and refractive index for both homogeneous (single-phase) ternary liquid mixtures (of known composition) and the corresponding binary compositions. Background information,…

Liquid crystals in biotribology synovial joint treatment

CERN Document Server

Ermakov, Sergey; Eismont, Oleg; Nikolaev, Vladimir

2016-01-01

This book summarizes the theoretical and experimental studies confirming the concept of the liquid-crystalline nature of boundary lubrication in synovial joints. It is shown that cholesteric liquid crystals in the synovial liquid play a significant role in the mechanism of intra-articular friction reduction. The results of structural, rheological and tribological research of the creation of artificial synovial liquids - containing cholesteric liquid crystals in natural synovial liquids - are described. These liquid crystals reproduce the lubrication properties of natural synovia and provide a high chondroprotective efficiency. They were tested in osteoarthritis models and in clinical practice.

Metastable Phase Separation and Concomitant Solute Redistribution of Liquid Fe-Cu-Sn Ternary Alloy

International Nuclear Information System (INIS)

Xiao-Mei, Zhang; Wei-Li, Wang; Ying, Ruan; Bing-Bo, Wei

2010-01-01

Liquid Fe-Cu-Sn ternary alloys with lower Sn contents are usually assumed to display a peritectic-type solidification process under equilibrium condition. Here we show that liquid Fe 47.5 Cu 47.5 Sn 5 ternary alloy exhibits a metastable immiscibility gap in the undercooling range of 51–329 K (0.19T L ). Macroscopic phase separation occurs once undercooling exceeds 196 K and causes the formation of a floating Fe-rich zone and a descending Cu-rich zone. Solute redistribution induces the depletion of Sn concentration in the Fe-rich zone and its enrichment in the Cu-rich zone. The primary Fe phase grows dendritically and its growth velocity increases with undercooling until the appearance of notable macrosegregation, but will decrease if undercooling further increases beyond 236 K. The microsegregation degrees of both solutes in Fe and Cu phases vary only slightly with undercooling. (condensed matter: structure, mechanical and thermal properties)

Biaxial nematic liquid crystals theory, simulation and experiment

CERN Document Server

Luckhurst, Geoffrey R

2015-01-01

Liquid Crystals are a state of matter that have properties between those of conventional liquid and those of a solid crystal. Thermotropic liquid crystals react to changes in temperature or, in some cases, pressure. The reaction of lyotropic liquid crystals, which are used in the manufacture of soaps and detergents, depends on the type of solvent they are mixed with. Since the accidental discovery of the chiral nematic (ordered) phase in 1888 many liquid crystal phases have been found, sometimes by chance and sometimes by design. The existence of one such phase was predicted by Freiser in 197

Ternary and quaternary (liquid + liquid) equilibria for (water + ethanol + α-pinene, +β-pinene, or +limonene) and (water + ethanol + α-pinene + limonene) at the temperature 298.15 K

International Nuclear Information System (INIS)

Li Hengde; Tamura, Kazuhiro

2006-01-01

(Liquid + liquid) equilibria and tie-lines for the ternary (water + ethanol + α-pinene, or β-pinene or limonene) and quaternary (water + ethanol + α-pinene + limonene) mixtures have been measured at T = 298.15 K. The experimental multicomponent (liquid + liquid) equilibrium data have been successfully represented in terms of the modified UNIQUAC model with binary parameters

Thermoelectricity in liquid crystals

Science.gov (United States)

Mohd Said, Suhana; Nordin, Abdul Rahman; Abdullah, Norbani; Balamurugan, S.

2015-09-01

The thermoelectric effect, also known as the Seebeck effect, describes the conversion of a temperature gradient into electricity. A Figure of Merit (ZT) is used to describe the thermoelectric ability of a material. It is directly dependent on its Seebeck coefficient and electrical conductivity, and inversely dependent on its thermal conductivity. There is usually a compromise between these parameters, which limit the performance of thermoelectric materials. The current achievement for ZT~2.2 falls short of the expected threshold of ZT=3 to allow its viability in commercial applications. In recent times, advances in organic thermoelectrics been significant, improving by over 3 orders of magnitude over a period of about 10 years. Liquid crystals are newly investigated as candidate thermoelectric materials, given their low thermal conductivity, inherent ordering, and in some cases, reasonable electrical conductivity. In this work the thermoelectric behaviour of a discotic liquid crystal, is discussed. The DLC was filled into cells coated with a charge injector, and an alignment of the columnar axis perpendicular to the substrate was allowed to form. This thermoelectric behavior can be correlated to the order-disorder transition. A reasonable thermoelectric power in the liquid crystal temperature regime was noted. In summary, thermoelectric liquid crystals may have the potential to be utilised in flexible devices, as a standalone power source.

Ultra-fast solid state electro-optical modulator based on liquid crystal polymer and liquid crystal composites

Energy Technology Data Exchange (ETDEWEB)

Ouskova, Elena; Sio, Luciano De, E-mail: luciano@beamco.com; Vergara, Rafael; Tabiryan, Nelson [Beam Engineering for Advanced Measurements Company, Winter Park, Florida 32789 (United States); White, Timothy J.; Bunning, Timothy J. [Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433-7707 (United States)

2014-12-08

A different generation of polymer-dispersed liquid crystals (PDLCs) based on a liquid crystalline polymer host is reported wherein the fluid behavior of the reactive mesogenic monomer is an enabler to concentration windows (liquid crystal polymer/liquid crystal) (and subsequent morphologies) not previously explored. These liquid crystal (LC) polymer/LC composites, LCPDLCs, exhibit excellent optical and electro-optical properties with negligible scattering losses in both the ON and OFF states. These systems thus have application in systems where fast phase modulation of optical signal instead of amplitude control is needed. Polarized optical microscopy and high resolution scanning electron microscopy confirm a bicontinuous morphology composed of aligned LC polymer coexisting with a phase separated LC fluid. Operating voltages, switching times, and spectra of LCPDLCs compare favourably to conventional PDLC films. The LCPDLCs exhibit a low switching voltage (4–5 V/μm), symmetric and submillisecond (200 μs) on/off response times, and high transmission in both the as formed and switched state in a phase modulation geometry.

separation of strontium and cesium from ternary and quaternary lithium chloride-potassium chloride salts via melt crystallization

Directory of Open Access Journals (Sweden)

Ammon N. Williams

2015-12-01

Full Text Available Separation of cesium chloride (CsCl and strontium chloride (SrCl2 from the lithium chloride-potassium chloride (LiCl-KCl salt was studied using a melt crystallization process similar to the reverse vertical Bridgeman growth technique. A ternary SrCl2-LiCl-KCl salt was explored at similar growth rates (1.8–5 mm/h and compared with CsCl ternary results to identify similarities. Quaternary experiments were also conducted and compared with the ternary cases to identify trends and possible limitations to the separations process. In the ternary case, as much as 68% of the total salt could be recycled per batch process. In the quaternary experiments, separation of Cs and Sr was nearly identical at the slower rates; however, as the growth rate increased, SrCl2 separated more easily than CsCl. The quaternary results show less separation and rate dependence than in both ternary cases. As an estimated result, only 51% of the total salt could be recycled per batch. Furthermore, two models have been explored to further understand the growth process and separation. A comparison of the experimental and modeling results reveals that the nonmixed model fits reasonably well with the ternary and quaternary data sets. A dimensional analysis was performed and a correlation was identified to semipredict the segregation coefficient.

Separation of strontium and cesium from ternary and quaternary lithium chloride-potassium chloride salts via melt crystallization

Energy Technology Data Exchange (ETDEWEB)

Williams, Ammon n.; Pack, Michael [Dept. of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond (United States); Phongikaroon, Spathorn [Dept. of Chemical and Materials Engineering and Nuclear Engineering Program, University of Idaho, Idaho Falls (United States)

2015-12-15

Separation of cesium chloride (CsCl) and strontium chloride (SrCl{sub 2}) from the lithium chloride-potassium chloride (LiCl-KCl) salt was studied using a melt crystallization process similar to the reverse vertical Bridgeman growth technique. A ternary SrCl2-LiCl-KCl salt was explored at similar growth rates (1.8-5 mm/h) and compared with CsCl ternary results to identify similarities. Quaternary experiments were also conducted and compared with the ternary cases to identify trends and possible limitations to the separations process. In the ternary case, as much as 68% of the total salt could be recycled per batch process. In the quaternary experiments, separation of Cs and Sr was nearly identical at the slower rates; however, as the growth rate increased, SrCl{sub 2} separated more easily than CsCl. The quaternary results show less separation and rate dependence than in both ternary cases. As an estimated result, only 51% of the total salt could be recycled per batch. Furthermore, two models have been explored to further understand the growth process and separation. A comparison of the experimental and modeling results reveals that the nonmixed model fits reasonably well with the ternary and quaternary data sets. A dimensional analysis was performed and a correlation was identified to semipredict the segregation coefficient.

Characterization of GaInSb crystal obtained by Czochralski Method

International Nuclear Information System (INIS)

Streicher, M.; Costa, E.M.; Dedavid, B.A.; Corregidor, V.; Franco, N.; Dias, M.; Alves, E.; Alves, L.C.

2014-01-01

The surface morphology and chemical composition of a Ga 0.93 In 0.07 Sb ternary alloy crystal grown by liquid encapsulated Czochralski were investigated by means of scanning electron microscope equipped with energy dispersive X-ray spectroscopy (SEM-EDX), particle induced X-ray emission (PIXE) and X-ray diffraction (XRD) techniques. Results indicate that poor mixing of the starting compounds during the synthesizing process lead to a ternary alloy with different compositions along the growth direction. Small regions with high concentrations of indium were highlighted throughout the crystal. Different parts removed from the crystal present similar microstructures with planar defects. Up to five different regions were identified in the sample. (author)

Characterization of GaInSb crystal obtained by Czochralski Method

Energy Technology Data Exchange (ETDEWEB)

Streicher, M.; Costa, E.M.; Dedavid, B.A. [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil); Corregidor, V.; Franco, N.; Dias, M.; Alves, E.; Alves, L.C. [Universidade de Lisboa, Sacavem (Portugal)

2014-07-01

The surface morphology and chemical composition of a Ga{sub 0.93}In{sub 0.07}Sb ternary alloy crystal grown by liquid encapsulated Czochralski were investigated by means of scanning electron microscope equipped with energy dispersive X-ray spectroscopy (SEM-EDX), particle induced X-ray emission (PIXE) and X-ray diffraction (XRD) techniques. Results indicate that poor mixing of the starting compounds during the synthesizing process lead to a ternary alloy with different compositions along the growth direction. Small regions with high concentrations of indium were highlighted throughout the crystal. Different parts removed from the crystal present similar microstructures with planar defects. Up to five different regions were identified in the sample. (author)

NMR spectroscopy using liquid crystal solvents

CERN Document Server

Emsley, JW

2013-01-01

NMR Spectroscopy using Liquid Crystal Solvents covers the importance of using a liquid crystal solvent in NMR to derive nuclear dipolar spin-spin coupling constants. This book is composed of ten chapters, and begins with a brief description of the features and benefits of liquid crystal in NMR spectroscopic analysis. The succeeding chapters deal with the mode of operation of nuclear spin Hamiltonian for partially oriented molecules and the analysis of NMR spectra of partially oriented molecules, as well as the determination of rigid molecule structure. These topics are followed by discussions

The crystallization of a solid solution in a solvent and the stability of a growth interface

International Nuclear Information System (INIS)

Malmejac, Yves

1971-03-01

The potential uses of germanium-silicon alloys as thermoelectric generators in hitherto unexploited temperature ranges initiated the present study. Many delicate problems are encountered in the classical methods of preparation. An original technique was sought for crystallization in a metallic solvent. The thermodynamic equilibria between the various phases of the ternary System used were studied in order to justify the method used. The conditions (temperature and composition) were determined in which the cooling of a ternary liquid mixture induces the precipitation of a binary solid solution with the desired composition. If large crystals are to be obtained from the solid solution, metallic solvent precipitation must be replaced by a mono-directional solvent crystallization. The combined effect of a certain number of simple physical phenomena on the stability of a crystal liquid interface was studied: the morphological stability of the crystal growth interface is the first step towards obtaining perfect crystals. (author) [fr

Computer modeling of liquid crystals

International Nuclear Information System (INIS)

Al-Barwani, M.S.

1999-01-01

In this thesis, we investigate several aspects of the behaviour of liquid crystal molecules near interfaces using computer simulation. We briefly discuss experiment, theoretical and computer simulation studies of some of the liquid crystal interfaces. We then describe three essentially independent research topics. The first of these concerns extensive simulations of a liquid crystal formed by long flexible molecules. We examined the bulk behaviour of the model and its structure. Studies of a film of smectic liquid crystal surrounded by vapour were also carried out. Extensive simulations were also done for a long-molecule/short-molecule mixture, studies were then carried out to investigate the liquid-vapour interface of the mixture. Next, we report the results of large scale simulations of soft-spherocylinders of two different lengths. We examined the bulk coexistence of the nematic and isotropic phases of the model. Once the bulk coexistence behaviour was known, properties of the nematic-isotropic interface were investigated. This was done by fitting order parameter and density profiles to appropriate mathematical functions and calculating the biaxial order parameter. We briefly discuss the ordering at the interfaces and make attempts to calculate the surface tension. Finally, in our third project, we study the effects of different surface topographies on creating bistable nematic liquid crystal devices. This was carried out using a model based on the discretisation of the free energy on a lattice. We use simulation to find the lowest energy states and investigate if they are degenerate in energy. We also test our model by studying the Frederiks transition and comparing with analytical and other simulation results. (author)

LIQUID-LIQUID EQUILIBRIA OF THE TERNARY SYSTEMS PROPIONIC ACID - WATER - SOLVENT (n-AMYL ALCOHOL AND n-AMYL ACETATE

Directory of Open Access Journals (Sweden)

Dilek ÖZMEN

2005-02-01

Full Text Available The experimental liquid-liquid equilibrium (LLE data have been obtained at 25 oC for ternary systems propionic acid-water-n-amyl alcohol and propionic acid-water-n-amyl acetate. The reliability of the experimental tie line data are checked using the methods of Othmer-Tobias and Hand. The distribution coefficients and separation factors were obtained from experimental results and are also reported. The predicted tie line data obtained by UNIFAC method are compared with experimental data. It is concluded that n-amyl alcohol and n-amyl acetate are suitable separating agents for dilute aqueous propionic acid solutions.

Key Developments in Ionic Liquid Crystals.

Science.gov (United States)

Alvarez Fernandez, Alexandra; Kouwer, Paul H J

2016-05-16

Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a molecular perspective. What are the important molecular parameters that determine the phase behavior? How should they be introduced into the molecules? Finally, which other tools does one have to realize specific properties in the material?

Key Developments in Ionic Liquid Crystals

Directory of Open Access Journals (Sweden)

Alexandra Alvarez Fernandez

2016-05-01

Full Text Available Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a molecular perspective. What are the important molecular parameters that determine the phase behavior? How should they be introduced into the molecules? Finally, which other tools does one have to realize specific properties in the material?

Alignment structures in ferroelectric liquid crystals

Energy Technology Data Exchange (ETDEWEB)

Islam, N.U

1998-07-01

Although for many years liquid crystals were of purely scientific interest, they have now become ubiquitous in everyday life. The use of the nematic liquid crystal phase in flat panel display applications has been the main factor in this popularity. However, with the advent of the SuperTwist Nematic (STN) device, the limits to which this phase could be exploited for display applications was perhaps reached. With the discovery by Clark et al. of the Surface Stabilised Ferroelectric Liquid Crystal (SSFLC) configuration, the possibility arose of using chiral smectic liquid crystals to create large area, passively addressed, fast switching, flat panel displays. Unfortunately, the structures that form within smectic liquid crystals, and the dynamics of the switching within these, are still not fully understood. In this thesis we address the former of these, making a detailed the study of the structures that form within tilted smectic liquid crystal devices. We present here the first complete theoretical and experimental study of various different ferroelectric liquid crystal materials, where we employed theoretical models based on a simple set of assumptions to understand the behaviour of a set of increasingly complex experimental systems. We started with the simplest of these, Freely Suspended Smectic Films (FSSFs) and then worked with progressively more realistic systems in the form of homeotropically, and later, homogeneously aligned liquid crystal cells. The equilibrium structures that form get particularly complex in the last case, taking the form of tilted and chevron layering structures. In each of these cases, the predictions of the modelling are compared with our experimental results. Further, we present here the first model of the chevron cusp that seeks to include the effects of biaxiality in the S{sub C} phase. We also present a model that seeks to analyse the stability of the chevron layering structure and its relationship with tilted layers. This includes

Alignment structures in ferroelectric liquid crystals

International Nuclear Information System (INIS)

Islam, N.U.

1998-01-01

Although for many years liquid crystals were of purely scientific interest, they have now become ubiquitous in everyday life. The use of the nematic liquid crystal phase in flat panel display applications has been the main factor in this popularity. However, with the advent of the SuperTwist Nematic (STN) device, the limits to which this phase could be exploited for display applications was perhaps reached. With the discovery by Clark et al. of the Surface Stabilised Ferroelectric Liquid Crystal (SSFLC) configuration, the possibility arose of using chiral smectic liquid crystals to create large area, passively addressed, fast switching, flat panel displays. Unfortunately, the structures that form within smectic liquid crystals, and the dynamics of the switching within these, are still not fully understood. In this thesis we address the former of these, making a detailed the study of the structures that form within tilted smectic liquid crystal devices. We present here the first complete theoretical and experimental study of various different ferroelectric liquid crystal materials, where we employed theoretical models based on a simple set of assumptions to understand the behaviour of a set of increasingly complex experimental systems. We started with the simplest of these, Freely Suspended Smectic Films (FSSFs) and then worked with progressively more realistic systems in the form of homeotropically, and later, homogeneously aligned liquid crystal cells. The equilibrium structures that form get particularly complex in the last case, taking the form of tilted and chevron layering structures. In each of these cases, the predictions of the modelling are compared with our experimental results. Further, we present here the first model of the chevron cusp that seeks to include the effects of biaxiality in the S C phase. We also present a model that seeks to analyse the stability of the chevron layering structure and its relationship with tilted layers. This includes an

Adsorption phenomena and anchoring energy in nematic liquid crystals

CERN Document Server

Barbero, Giovanni

2005-01-01

Despite the large quantity of phenomenological information concerning the bulk properties of nematic phase liquid crystals, little is understood about the origin of the surface energy, particularly the surface, interfacial, and anchoring properties of liquid crystals that affect the performance of liquid crystal devices. Self-contained and unique, Adsorption Phenomena and Anchoring Energy in Nematic Liquid Crystals provides an account of new and established results spanning three decades of research into the problems of anchoring energy and adsorption phenomena in liquid crystals.The book contains a detailed discussion of the origin and possible sources of anchoring energy in nematic liquid crystals, emphasizing the dielectric contribution to the anchoring energy in particular. Beginning with fundamental surface and anchoring properties of liquid crystals and the definition of the nematic phase, the authors explain how selective ion adsorption, dielectric energy density, thickness dependence, and bias voltage...

Liquid crystalline biopolymers: A new arena for liquid crystal research

International Nuclear Information System (INIS)

Rizvi, Tasneem Zahra

2001-07-01

This paper gives a brief introduction to liquid crystals on the basis of biopolymers and reviews literature on liquid crystalline behaviour of biopolymers both in vitro and in vivo in relation to their implications in the fields of biology, medicine and material science. Knowledge in the field of biological liquid crystals is crucial for understanding complex phenomena at supramolecular level which will give information about processes involved in biological organization and function. The understanding of the interaction of theses crystals with electric, magnetic, optical and thermal fields will uncover mechanisms of near quantum-energy detection capabilities of biosystems

Chromatic dispersion of liquid crystal infiltrated capillary tubes and photonic crystal fibers

DEFF Research Database (Denmark)

Rasmussen, Per Dalgaard; Lægsgaard, Jesper; Bang, Ole

2006-01-01

We consider chromatic dispersion of capillary tubes and photonic crystal fibers infiltrated with liquid crystals. A perturbative scheme for inclusion of material dispersion of both liquid crystal and the surrounding waveguide material is derived. The method is used to calculate the chromatic...

Liquid crystals for organic transistors (Conference Presentation)

Science.gov (United States)

Hanna, Jun-ichi; Iino, Hiroaki

2016-09-01

Liquid crystals are a new type of organic semiconductors exhibiting molecular orientation in self-organizing manner, and have high potential for device applications. In fact, various device applications have been proposed so far, including photosensors, solar cells, light emitting diodes, field effect transistors, and so on.. However, device performance in those fabricated with liquid crystals is less than those of devices fabricated with conventional materials in spite of unique features of liquid crystals. Here we discuss how we can utilize the liquid crystallinity in organic transistors and how we can overcome conventional non-liquid crystalline organic transistor materials. Then, we demonstrate high performance organic transistors fabricated with a smectic E liquid crystal of Ph-BTBT-10, which show high mobility of over 10cm2/Vs and high thermal durability of over 200oC in OFETs fabricated with its spin-coated polycrystalline thin films.

(Vapour + liquid) equilibria for binary and ternary mixtures of 2-propanol, tetrahydropyran, and 2,2,4-trimethylpentane at P = 101.3 kPa

International Nuclear Information System (INIS)

Lin, Dun-Yi; Tu, Chein-Hsiun

2012-01-01

Highlights: ► We report the VLE data at P = 101.3 kPa involving a cyclic ether. ► The activity coefficients of mixtures were obtained from modified Raoult’s law. ► The VLE data were correlated by four liquid activity coefficient models. ► The ternary VLE data were predicted from binary parameters of the four models. - Abstract: (Vapour + liquid) equilibrium (VLE) at P = 101.3 kPa have been determined for a ternary system (2-propanol + tetrahydropyran + 2,2,4-trimethylpentane) and its constituent binary systems (2-propanol + tetrahydropyran, 2-propanol + 2,2,4-trimethylpentane), and (tetrahydropyran + 2,2,4-trimethylpentane). Analysis of VLE data reveals that two binary systems (2-propanol + tetrahydropyran) and (2-propanol + 2,2,4-trimethylpentane) have a minimum boiling azeotrope. No azeotrope was found for the ternary system. The activity coefficients of liquid mixtures were obtained from the modified Raoult’s law and were used to calculate the reduced excess molar Gibbs free energy (g E /RT). Thermodynamic consistency tests were performed for all VLE data using the Van Ness direct test for the binary systems and the test of McDermott–Ellis as modified by Wisniak and Tamir for the ternary system. The VLE data of the binary mixtures were correlated using the three-suffix Margules, Wilson, NRTL, and UNIQUAC activity-coefficient models. The models with their best-fitted interaction parameters of the binary systems were used to predict the ternary (vapour + liquid) equilibrium.

Chem I Supplement: Liquid Crystals--The Chameleon Chemicals.

Science.gov (United States)

Brown, Glenn H.

1983-01-01

Presents information relevant to everyday life so as to stimulate student interest in the properties of the two basic types of liquid crystals: thermotropic and lyotropic. Describes the applications of liquid crystals to electronics, biomedicine, and polymer science and appraises the future of liquid crystal research. (JM)

Strong dielectric liquid crystal polymer (Part 3)

Energy Technology Data Exchange (ETDEWEB)

Kurata, Hideaki; Shibasaki, Akira

1988-11-01

Influence of change of molecular parameters on liquid crystal condition is studied to get the correlation between molecular structure of liquid crystal and phase structure or visco-elastic properties. Eight kinds of biphenyl type liquid crystals with polyacrilate main chain and triphenyl type liquid crystals were used as samples. Followings were found by a ploarizing microscope and X-ray diffraction: Phases are transferred from isotropic phase S/sub A/ phase S/sup *//sub C/ phase S/sub 1/ phase to solid on temperature desending sequence. Degree of polymerization changes only these transfer point but spacer length affects not only transfer points and layer distance but also liquid crystal structure itself. Visco-elasticity of isotropic phase shows Newtonian viscosity and is affected by the main chain length. Macroscopic and microscopic structures influence on viscoelasticity in S/sub A/ phase and S/sup *//sub C/ phase. Two rapid rises of viscoelasticity are found in low molecular weight liquid crystal when S/sub A/ transfer and S/sub A/ to S/sup *//sub C/ transfer occur by temperature desending from the isotropic phase. Viscoelastic behavior is contributed by the properties of domain itself and interaction between domains, and the interaction is changed by polymerization. 6 references, 13 figures, 1 table.

Liquid crystals of carbon nanotubes and graphene.

Science.gov (United States)

Zakri, Cécile; Blanc, Christophe; Grelet, Eric; Zamora-Ledezma, Camilo; Puech, Nicolas; Anglaret, Eric; Poulin, Philippe

2013-04-13

Liquid crystal ordering is an opportunity to develop novel materials and applications with spontaneously aligned nanotubes or graphene particles. Nevertheless, achieving high orientational order parameter and large monodomains remains a challenge. In addition, our restricted knowledge of the structure of the currently available materials is a limitation for fundamental studies and future applications. This paper presents recent methodologies that have been developed to achieve large monodomains of nematic liquid crystals. These allow quantification and increase of their order parameters. Nematic ordering provides an efficient way to prepare conductive films that exhibit anisotropic properties. In particular, it is shown how the electrical conductivity anisotropy increases with the order parameter of the nematic liquid crystal. The order parameter can be tuned by controlling the length and entanglement of the nanotubes. In the second part of the paper, recent results on graphene liquid crystals are reported. The possibility to obtain water-based liquid crystals stabilized by surfactant molecules is demonstrated. Structural and thermodynamic characterizations provide indirect but statistical information on the dimensions of the graphene flakes. From a general point of view, this work presents experimental approaches to optimize the use of nanocarbons as liquid crystals and provides new methodologies for the still challenging characterization of such materials.

Crystal Structures of Murine Carnitine Acetyltransferase in Ternary Complexes with Its Substrates

Energy Technology Data Exchange (ETDEWEB)

Hsiao,Y.; Jogl, G.; Tong, L.

2006-01-01

Carnitine acyltransferases catalyze the reversible exchange of acyl groups between coenzyme A (CoA) and carnitine. They have important roles in many cellular processes, especially the oxidation of long-chain fatty acids in the mitochondria for energy production, and are attractive targets for drug discovery against diabetes and obesity. To help define in molecular detail the catalytic mechanism of these enzymes, we report here the high resolution crystal structure of wild-type murine carnitine acetyltransferase (CrAT) in a ternary complex with its substrates acetyl-CoA and carnitine, and the structure of the S554A/M564G double mutant in a ternary complex with the substrates CoA and hexanoylcarnitine. Detailed analyses suggest that these structures may be good mimics for the Michaelis complexes for the forward and reverse reactions of the enzyme, representing the first time that such complexes of CrAT have been studied in molecular detail. The structural information provides significant new insights into the catalytic mechanism of CrAT and possibly carnitine acyltransferases in general.

Lasing in liquid crystal thin films

Energy Technology Data Exchange (ETDEWEB)

Palto, S. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)], E-mail: palto@online.ru

2006-09-15

A lasing condition is formulated in matrix form for optically anisotropic thin films. Lasing behavior of liquid-crystal slabs is analyzed. In particular, it is shown that if the spatial extent of a liquid crystal slab is much larger than its thickness, then laser emission is feasible not only along the normal to the slab, but also in the entire angular sector. The generated laser light can be observed experimentally as a spot or as concentric rings on a screen. The lowest lasing threshold corresponds to in-plane sliding modes leaking into the substrate. The feedback required for lasing is provided by reflection from the interfaces, rather than edges, of the liquid-crystal slab operating as a planar Fabry-Perot cavity. For cholesteric liquid crystals, it is shown that energy loss to the sliding modes leaking into the substrates and escaping through their edges is a key factor that limits the efficiency of band-edge emission along the normal to the slab.

Ionic Liquid Crystals: Versatile Materials.

Science.gov (United States)

Goossens, Karel; Lava, Kathleen; Bielawski, Christopher W; Binnemans, Koen

2016-04-27

This Review covers the recent developments (2005-2015) in the design, synthesis, characterization, and application of thermotropic ionic liquid crystals. It was designed to give a comprehensive overview of the "state-of-the-art" in the field. The discussion is focused on low molar mass and dendrimeric thermotropic ionic mesogens, as well as selected metal-containing compounds (metallomesogens), but some references to polymeric and/or lyotropic ionic liquid crystals and particularly to ionic liquids will also be provided. Although zwitterionic and mesoionic mesogens are also treated to some extent, emphasis will be directed toward liquid-crystalline materials consisting of organic cations and organic/inorganic anions that are not covalently bound but interact via electrostatic and other noncovalent interactions.

Electrically Tuned Microwave Devices Using Liquid Crystal Technology

Directory of Open Access Journals (Sweden)

Pouria Yaghmaee

2013-01-01

Full Text Available An overview of liquid crystal technology for microwave and millimeter-wave frequencies is presented. The potential of liquid crystals as reconfigurable materials arises from their ability for continuous tuning with low power consumption, transparency, and possible integration with printed and flexible circuit technologies. This paper describes physical theory and fundamental electrical properties arising from the anisotropy of liquid crystals and overviews selected realized liquid crystal devices, throughout four main categories: resonators and filters, phase shifters and delay lines, antennas, and, finally, frequency-selective surfaces and metamaterials.

Photonics of liquid-crystal structures: A review

Energy Technology Data Exchange (ETDEWEB)

Palto, S. P., E-mail: palto@online.ru; Blinov, L M; Barnik, M I; Lazarev, V V; Umanskii, B A; Shtykov, N M [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2011-07-15

The original results of studies of the electro-optical and laser effects which have been performed at the Laboratory of Liquid Crystals of the Institute of Crystallography, Russian Academy of Sciences, over the last few years are reviewed. Cholesteric liquid crystals as vivid representatives of photonic structures and their behavior in an electric field are considered in detail. The formation of higher harmonics in the periodic distribution of the director field in a helical liquid crystal structure and, correspondingly, the new (anharmonic) mode of electro-optical effects are discussed. Another group of studies is devoted to bistable light switching by an electric field in chiral nematics. Polarization diffraction gratings controlled by an electric field are also considered. The results of studies devoted to microlasers on various photonic structures with cholesteric and nematic liquid crystals are considered in detail. Particular attention is given to the new regime: leaky-mode lasing. Designs of liquid crystal light amplifiers and their polarization, field, and spectral characteristics are considered in the last section.

Demonstrations with a Liquid Crystal Shutter

Science.gov (United States)

Kraftmakher, Yaakov

2012-01-01

The experiments presented show the response of a liquid crystal shutter to applied electric voltages and the delay of the operations. Both properties are important for liquid crystal displays of computers and television sets. Two characteristics of the shutter are determined: (i) the optical transmittance versus applied voltage of various…

Control of liquid crystal molecular orientation using ultrasound vibration

Energy Technology Data Exchange (ETDEWEB)

Taniguchi, Satoki [Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Wave Electronics Research Center, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Koyama, Daisuke; Matsukawa, Mami [Wave Electronics Research Center, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Faculty of Science and Engineering, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Shimizu, Yuki; Emoto, Akira [Faculty of Science and Engineering, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321 (Japan); Nakamura, Kentaro [Precision and Intelligence Laboratory, Tokyo Institute of Technology, 4259-R2-26, Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan)

2016-03-07

We propose a technique to control the orientation of nematic liquid crystals using ultrasound and investigate the optical characteristics of the oriented samples. An ultrasonic liquid crystal cell with a thickness of 5–25 μm and two ultrasonic lead zirconate titanate transducers was fabricated. By exciting the ultrasonic transducers, the flexural vibration modes were generated on the cell. An acoustic radiation force to the liquid crystal layer was generated, changing the molecular orientation and thus the light transmission. By modulating the ultrasonic driving frequency and voltage, the spatial distribution of the molecular orientation of the liquid crystals could be controlled. The distribution of the transmitted light intensity depends on the thickness of the liquid crystal layer because the acoustic field in the liquid crystal layer is changed by the orientational film.

Ternary scandium and transition metals germanides

International Nuclear Information System (INIS)

Kotur, B.Ya.

1992-01-01

Brief review of data on phase diagram of ternary Sc-Me-Ge systems (Me-d - , f-transition element) is given. Isothermal sections at 870 and 1070 K of 17 ternary systems are plotted. Compositions and their structural characteristics are presented. Variability of crystal structure is typical for ternary scandium germanides: 70 compounds with the studied structure belong to 23 structural types. Ternary germanides isostructural to types of Sm 4 Ge 4 , ZrCrSi 2 , ZrNiAl, ScCeSi, TiNiSi U 4 Re 7 Si 6 145 compounds from 70 under investigation are mostly formed in studied systems

Alignment technology and applications of liquid crystal devices

CERN Document Server

Takatoh, Kohki; Hasegawa, Ray; Koden, Mitsushiro; Itoh, Nobuyuki; Hasegawa, Masaki

2005-01-01

Alignment phenomena are characteristic of liquid crystalline materials, and understanding them is critically important in understanding the essential features and behavior of liquid crystals and the performance of Liquid Crystal Devices (LCDs). Furthermore, in LCD production lines, the alignment process is of practical importance. Alignment Technologies and Applications of Liquid Crystal Devices demonstrates both the fundamental and practical aspects of alignment phenomena in liquid crystals. The physical basis of alignment phenomena is first introduced in order to aid the understanding of the various physical phenomena observed in the interface between liquid crystalline materials and alignment layer surfaces. Methods for the characterization of surfaces, which induce the alignment phenomena, and of the alignment layer itself are introduced. These methods are useful for the research of liquid crystalline materials and devices in academic research as well as in industry. In the practical sections, the alignme...

Application of liquid crystals in thermal nondestructive evaluation

International Nuclear Information System (INIS)

Panakal, J.P.; Mukherjee, S.; Ghosh, J.K.

1983-01-01

In recent years, thermal nondestructive evaluation using Cholestric liquid crystals have found wide applications in industry. Thermography using Cholesteric liquid crystals can be used for detection of nonbonds in metallic composites, hot spots in electronic circuits and preliminary examination of welded pressure vessels. This paper presents the results of experiments on thermography of components using encapsulated liquid crystals. (author)

Quantum Dot/Liquid Crystal Nanocomposites in Photonic Devices

Directory of Open Access Journals (Sweden)

Andrea L. Rodarte

2015-07-01

Full Text Available Quantum dot/liquid crystal nano-composites are promising new materials for a variety of applications in energy harvesting, displays and photonics including the liquid crystal laser. To realize many applications, however, we need to control and stabilize nano-particle dispersion in different liquid crystal host phases and understand how the particles behave in an anisotropic fluid. An ideal system will allow for the controlled assembly of either well-defined nano-particle clusters or a uniform particle distribution. In this paper, we investigate mesogen-functionalized quantum dots for dispersion in cholesteric liquid crystal. These nanoparticles are known to assemble into dense stable packings in the nematic phase, and such structures, when localized in the liquid crystal defects, can potentially enhance the coupling between particles and a cholesteric cavity. Controlling the dispersion and assembly of quantum dots using mesogenic surface ligands, we demonstrate how resonant fluid photonic cavities can result from the co-assembly of luminescent nanoparticles in the presence of cholesteric liquid crystalline ordering.

Enhanced fluidity liquid chromatography of inulin fructans using ternary solvent strength and selectivity gradients.

Science.gov (United States)

Bennett, Raffeal; Olesik, Susan V

2018-01-25

The value of exploring selectivity and solvent strength ternary gradients in enhanced fluidity liquid chromatography (EFLC) is demonstrated for the separation of inulin-type fructans from chicory. Commercial binary pump systems for supercritical fluid chromatography only allow for the implementation of ternary solvent strength gradients which can be restrictive for the separation of polar polymeric analytes. In this work, a custom system was designed to extend the capability of EFLC to allow tuning of selectivity or solvent strength in ternary gradients. Gradient profiles were evaluated using the Berridge function (RF 1 ), normalized resolution product (NRP), and gradient peak capacity (P c ). Selectivity gradients provided the separation of more analytes over time. The RF 1 function showed favor to selectivity gradients with comparable P c to that of solvent strength gradients. NRP did not strongly correlate with P c or RF 1 score. EFLC with the hydrophilic interaction chromatography, HILIC, separation mode was successfully employed to separate up to 47 fructan analytes in less than 25 min using a selectivity gradient. Copyright © 2017 Elsevier B.V. All rights reserved.

(Liquid + liquid) equilibria for the ternary mixtures (alkane + toluene + ionic liquid) at T = 298.15 K: Influence of the anion on the phase equilibria

International Nuclear Information System (INIS)

Seoane, Raquel G.; Gómez, Elena; González, Emilio J.; Domínguez, Ángeles

2012-01-01

Highlights: ► [BMpyr][NTF 2 ] and [BMpyr][TFO] were studied as solvents to extract aromatics from alkanes. ► (Liquid + liquid) equilibrium data were measured at 298.15 K for six ternary systems. ► Selectivity and solute distribution ratio were calculated and compared. ► The influence of the structure of anion of the ionic liquid was analyzed. ► Experimental data were satisfactorily correlated using NRTL model. - Abstract: (Liquid + liquid) equilibrium data for the ionic liquids 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [BMpyr][NTf 2 ], and 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate, [BMpyr][TFO], with toluene, and heptane or cyclohexane were determined at T = 298.15 K and atmospheric pressure. In order to check if these ILs can be used as potential solvents for the extraction of toluene from aliphatic compounds, the ability of the ILs as solvents was evaluated in terms of selectivity and solute distribution ratio. The experimental data were correlated accurately with the Non Random Two-Liquid model.

Modified dynamical equation for dye doped nematic liquid crystals

Energy Technology Data Exchange (ETDEWEB)

Manohar, Rajiv, E-mail: rajlu1@rediffmail.co [Liquid Crystal Research Lab, Physics Department, University of Lucknow, Lucknow 226007 (India); Misra, Abhishek Kumar; Srivastava, Abhishek Kumar [Liquid Crystal Research Lab, Physics Department, University of Lucknow, Lucknow 226007 (India)

2010-04-15

Dye doped liquid crystals show changed dielectric properties in comparison to pure liquid crystals. These changes are strongly dependent on the concentration of dye. In the present work we have measured dielectric properties of standard nematic liquid crystals E-24 and its two guest host mixtures of different concentrations with Anthraquinone dye D5. The experimental results are fitted using linear response and in the light of this we have proposed some modifications in the dynamical equation for the nematic liquid crystals by introducing two new variables as dye concentration coefficients. The limitations of the proposed equation in high temperature range have also been discussed. With the help of the proposed dynamical equation for the guest-host liquid crystals (GHLCs) it is possible to predict the various parameters like rotational viscosity, dielectric anisotropy and relaxation time for GHLCs at other concentrations of dye in liquid crystals theoretically.

Ebulliometric determination and prediction of (vapor + liquid) equilibria for binary and ternary mixtures containing alcohols (C1-C4) and dimethyl carbonate

International Nuclear Information System (INIS)

Matsuda, Hiroyuki; Fukano, Makoto; Kikkawa, Shinichiro; Constantinescu, Dana; Kurihara, Kiyofumi; Tochigi, Katsumi; Ochi, Kenji; Gmehling, Juergen

2012-01-01

Highlights: → The VLE behavior of systems containing dimethyl carbonate (DMC) was investigated. → VLE data for ternary and binary mixtures containing alcohol and DMC were measured. → Several activity coefficient models were used for data reduction or prediction. → Valley line, i.e., distillation boundary, was observed for the ternary mixture. → Residue curves were calculated to investigate composition profile for distillation. - Abstract: (Vapor + liquid) equilibrium (VLE) data for a ternary mixture, namely {methanol + propan-1-ol + dimethyl carbonate (DMC)}, and four binary mixtures, namely an {alcohol (C 3 or C 4 ) + DMC}, containing the binary constituent mixtures of the ternary mixture, were measured at p = (40.00 to 93.32) kPa using a modified Swietoslawski-type ebulliometer. The experimental data for the binary systems were correlated using the Wilson model. The Wilson model was also applied to the ternary system to predict the VLE behavior using parameters from the binary mixtures. The modified UNIFAC (Dortmund) model was also tested for the predictions of the VLE behavior of the binary and ternary mixtures. In addition, the experimental VLE data for the ternary and constituent binary mixtures were correlated using the extended Redlich-Kister (ERK) model, which can completely represent the azeotropic points. For the ternary system, a comparison of the experimental and the predicted or correlated boiling points obtained using the Wilson and ERK models showed that the ERK model is more accurate. The valley line, i.e., the curve which divides the patterns of vapor-liquid tie lines, was found in the (methanol + propan-1-ol + DMC) system. This valley line could be represented by the ERK model. Finally, the composition profile for simple distillation of this ternary mixture was obtained by analysis of the residue curves from the estimated Wilson parameters of the constituent binary mixtures.

Nanoscience with liquid crystals from self-organized nanostructures to applications

CERN Document Server

Li, Quan

2014-01-01

This book focuses on the exciting topic of nanoscience with liquid crystals: from self-organized nanostructures to applications. The elegant self-organized liquid crystalline nanostructures, the synergetic characteristics of liquid crystals and nanoparticles, liquid crystalline nanomaterials, synthesis of nanomaterials using liquid crystals as templates, nanoconfinement and nanoparticles of liquid crystals are covered and discussed, and the prospect of fabricating functional materials is highlighted. Contributions, collecting the scattered literature of the field from leading and active player

Liquid crystal dimers

CERN Document Server

Kumar Pal, Santanu

2017-01-01

This book covers in-depth discussion of design principles, synthesis and thermal behavior of all types of liquid crystal (LC) dimers. The text presents recent advances in the field of LC dimers consisting of different mesogenic units such as calamitic, discotic and bent-core molecules. It starts with a chapter on the introduction of liquid crystal dimers, including their odd-even behavior, basic classification of dimers and common mesophases in dimers. The text shows how the molecular architectures are being used to develop new materials to study a range of interesting phenomena such as the biaxial nematic phase containing rod-like and disc-like mesogenic units. Finally, the text presents perspectives related to technological relevance of these dimers such as dopants in LC display mixtures exhibiting faster relaxation time, strong flexoelectric coupling and others to effect control over the properties of these materials.

Liquid crystals: high technology materials for potential applications

International Nuclear Information System (INIS)

Saeed, M.A.; Badaruddin; Rizvi, T.Z.

1993-01-01

Liquid crystals have very rapidly emerged as a basis of many high technology fields within the last few decades. These materials because of their intriguing physical properties are regarded as the fourth state of matter. At present the applications of liquid crystals are established in digital display devices, electro-optical switches, optical computing, acousto-optics, thermo-indicators, laser thermo-recording, photo-chemical image recording and optical communication networks. More recently due to the concept of molecularly based electronics (MBE): the logical extreme for miniaturization of electronic device, liquid crystals are foreseen to play a vital role in the future optics based technologies. This paper gives a brief introduction to liquid crystals, the types of meso phases found in these materials together with their applications in research and industry. Some technical details of the construction liquid crystal cells for some typical applications in digital displays and other electro optical devices have also been discussed with special emphasis on relevant physical processes occurring at molecular level. (author)

Insertion of liquid crystal molecules into hydrocarbon monolayers

Energy Technology Data Exchange (ETDEWEB)

Popov, Piotr, E-mail: ppopov@kent.edu; Mann, Elizabeth K. [Department of Physics, Kent State University, Kent, Ohio 44242 (United States); Lacks, Daniel J. [Department of Chemical Engineering, Case Western Reserve University, Cleveland, Ohio 44106 (United States); Jákli, Antal [Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001 (United States)

2014-08-07

Atomistic molecular dynamics simulations were carried out to investigate the molecular mechanisms of vertical surface alignment of liquid crystals. We study the insertion of nCB (4-Cyano-4{sup ′}-n-biphenyl) molecules with n = 0,…,6 into a bent-core liquid crystal monolayer that was recently found to provide good vertical alignment for liquid crystals. The results suggest a complex-free energy landscape for the liquid crystal within the layer. The preferred insertion direction of the nCB molecules (core or tail first) varies with n, which can be explained by entropic considerations. The role of the dipole moments was found to be negligible. As vertical alignment is the leading form of present day liquid crystal displays (LCD), these results will help guide improvement of the LCD technology, as well as lend insight into the more general problem of insertion of biological and other molecules into lipid and surfactant layers.

All-optical image processing with nonlinear liquid crystals

Science.gov (United States)

Hong, Kuan-Lun

Liquid crystals are fascinating materials because of several advantages such as large optical birefringence, dielectric anisotropic, and easily compatible to most kinds of materials. Compared to the electro-optical properties of liquid crystals widely applied in displays and switching application, transparency through most parts of wavelengths also makes liquid crystals a better candidate for all-optical processing. The fast response time of liquid crystals resulting from multiple nonlinear effects, such as thermal and density effect can even make real-time processing realized. In addition, blue phase liquid crystals with spontaneously self-assembled three dimensional cubic structures attracted academic attention. In my dissertation, I will divide the whole contents into six parts. In Chapter 1, a brief introduction of liquid crystals is presented, including the current progress and the classification of liquid crystals. Anisotropy and laser induced director axis reorientation is presented in Chapter 2. In Chapter 3, I will solve the electrostrictive coupled equation and analyze the laser induced thermal and density effect in both static and dynamic ways. Furthermore, a dynamic simulation of laser induced density fluctuation is proposed by applying finite element method. In Chapter 4, two image processing setups are presented. One is the intensity inversion experiment in which intensity dependent phase modulation is the mechanism. The other is the wavelength conversion experiment in which I can read the invisible image with a visible probe beam. Both experiments are accompanied with simulations to realize the matching between the theories and practical experiment results. In Chapter 5, optical properties of blue phase liquid crystals will be introduced and discussed. The results of grating diffractions and thermal refractive index gradient are presented in this chapter. In addition, fiber arrays imaging and switching with BPLCs will be included in this chapter

Electrically tunable liquid crystal photonic bandgap fiber laser

DEFF Research Database (Denmark)

Olausson, Christina Bjarnal Thulin; Scolari, Lara; Wei, Lei

2010-01-01

We demonstrate electrical tunability of a fiber laser by using a liquid crystal photonic bandgap fiber. Tuning of the laser is achieved by combining the wavelength filtering effect of a liquid crystal photonic bandgap fiber device with an ytterbium-doped photonic crystal fiber. We fabricate an al...

Microwave modulation characteristics of twisted liquid crystals with chiral dopant

Directory of Open Access Journals (Sweden)

Rui Yuan

2017-01-01

Full Text Available Adding a chiral dopant in twisted nematic (TN liquid crystal cell can stabilize the orientation of liquid crystal molecules, particularly in high TN (HTN or super TN (STN liquid crystal cells. The difference in pitches in liquid crystal is induced by the chiral dopant, and these different pitches affect the orientation of liquid crystal director under an external applied voltage and influence the characteristics of microwave modulation. To illustrate this point, the microwave phase shift per unit length (MPSL versus voltage is calculated on the basis of the elastic theory of liquid crystal and the finite-difference iterative method. Enhancing the pitch induced by the chiral dopant in liquid crystal increases the MPSLs, but the stability of the twisted structures is decreased. Thus, appropriate pitches of 100d, 4d, and 2d can be applied in TN, HTN, and STN cells with cell gap d to enhance the characteristics of microwave modulation and stabilize the structures in twisted cell. This method can improve the characteristics of liquid crystal microwave modulators such that the operating voltage and the size of such phase shifters can be decreased.

Liquid crystal parameter analysis for tunable photonic bandgap fiber devices

DEFF Research Database (Denmark)

Weirich, Johannes; Lægsgaard, Jesper; Wei, Lei

2010-01-01

We investigate the tunability of splay-aligned liquid crystals for the use in solid core photonic crystal fibers. Finite element simulations are used to obtain the alignment of the liquid crystals subject to an external electric field. By means of the liquid crystal director field the optical...

New scintillating media based on liquid crystals for particle detectors

International Nuclear Information System (INIS)

Barnik, M.I.; Yudin, S.G.; Vasil'chenko, V.G.; Golovkin, S.V.; Medvedkov, A.M.; Solovjev, A.S.

2000-01-01

The study results of optical, photoluminiscent and scintillation properties of a liquid crystal 4-pentyl-4'-cyanobiphenyl are presented. The scintillation light output of this liquid crystal is about 35% of crystal anthracene, its main decay time constants are 4 and 14 ns, and the maximum of light emission spectrum is about 400 nm. The light output of a dissolution of green emitting light scintillation dopant R6 in the liquid crystal is about 120% of crystal anthracene. The light output of the frozen dissolution measured at -112 deg. C is about 2.5 times higher as observed at +20 deg. C. In the uniaxially oriented liquid crystal, the predominant intensity direction of emitted light is pointed perpendicular to the liquid crystal director and an appreciable part of the emitted light is elliptically polarized. The possibility to use scintillation properties of liquid crystals is considered both for the improvement of existing particle detector characteristics and for the creation of new gated particle detectors

New scintillating media based on liquid crystals for particle detectors

CERN Document Server

Barnik, M I; Vasilchenko, V G; Golovkin, S V; Medvedkov, A M; Soloviev, A S

2000-01-01

The study results of optical, photoluminiscent and scintillation properties of a liquid crystal 4-pentyl-4'-cyanobiphenyl are presented. The scintillation light output of this liquid crystal is about 35% of crystal anthracene, its main decay time constants are 4 and 14 ns, and the maximum of light emission spectrum is about 400 nm. The light output of a dissolution of green emitting light scintillation dopant R6 in the liquid crystal is about 120% of crystal anthracene. The light output of the frozen dissolution measured at -112 deg. C is about 2.5 times higher as observed at +20 deg. C. In the uniaxially oriented liquid crystal, the predominant intensity direction of emitted light is pointed perpendicular to the liquid crystal director and an appreciable part of the emitted light is elliptically polarized. The possibility to use scintillation properties of liquid crystals is considered both for the improvement of existing particle detector characteristics and for the creation of new gated particle detectors.

Determination and modeling of binary and ternary solid-liquid phase equilibrium for the systems formed by 1,8-dinitronaphthalene and 1,5-dinitronaphthalene and N-methyl-2-pyrrolidone

International Nuclear Information System (INIS)

Xie, Yong; Du, Cunbin; Cong, Yang; Wang, Jian; Han, Shuo; Zhao, Hongkun

2016-01-01

Highlights: • SLE formed by 1,5 and/or 1,8-dinitronaphthalene and NMP was determined. • The binary and ternary phase diagrams were constructed. • The phase diagrams were correlated and calculated using thermodynamic models. - Abstract: The solubility of 1,8-dinitronaphthalene and 1,5-dinitronaphthalene in N-methyl-2-pyrrolidone at (293.15–343.15) K and the mutual solubility of the ternary 1,5-dinitronaphthalene + 1,8-dinitronaphthalene + N-methyl-2-pyrrolidone mixture at (313.15, 328.15 and 343.15) K were determined experimentally using the isothermal saturation method under atmospheric pressure (101.2 kPa). The solubility of 1,8-dinitronaphthalene in N-methyl-2-pyrrolidone is larger than that of 1,5-dinitronaphthalene. Three isothermal ternary phase diagrams were built according to the measured mutual solubility data. In each ternary phase diagram, there were one co-saturated point, two boundary curves, and three crystalline regions. Two pure solids (pure 1,8-dinitronaphthalene and pure 1,5-dinitronaphthalene) were formed in the ternary system at a given temperature, which were identified by Schreinemaker’s method of wet residue and powder X-ray diffraction (PXRD) pattern. The crystallization region of 1,8-dinitronaphthalene was smaller than that of 1,5-dinitronaphthalene at each temperature. The modified Apelblat equation, λh equation, NRTL model and Wilson model were used to correlate the solubility of 1,8-dinitronaphthalene and 1,5-dinitronaphthalene in N-methyl-2-pyrrolidone; and the NRTL and Wilson models were employed to correlate and calculate the mutual solubility for the ternary 1,5-dinitronaphthalene + 1,8-dinitronaphthalene + N-methyl-2-pyrrolidone system. The largest value of root-mean-square deviation (RMSD) was 20.34 × 10 −4 for the binary systems; and 7.38 × 10 −3 for ternary system. The calculated results via these models are all acceptable for the binary and ternary solid-liquid phase equilibrium.

Large three-dimensional photonic crystals based on monocrystalline liquid crystal blue phases.

Science.gov (United States)

Chen, Chun-Wei; Hou, Chien-Tsung; Li, Cheng-Chang; Jau, Hung-Chang; Wang, Chun-Ta; Hong, Ching-Lang; Guo, Duan-Yi; Wang, Cheng-Yu; Chiang, Sheng-Ping; Bunning, Timothy J; Khoo, Iam-Choon; Lin, Tsung-Hsien

2017-09-28

Although there have been intense efforts to fabricate large three-dimensional photonic crystals in order to realize their full potential, the technologies developed so far are still beset with various material processing and cost issues. Conventional top-down fabrications are costly and time-consuming, whereas natural self-assembly and bottom-up fabrications often result in high defect density and limited dimensions. Here we report the fabrication of extraordinarily large monocrystalline photonic crystals by controlling the self-assembly processes which occur in unique phases of liquid crystals that exhibit three-dimensional photonic-crystalline properties called liquid-crystal blue phases. In particular, we have developed a gradient-temperature technique that enables three-dimensional photonic crystals to grow to lateral dimensions of ~1 cm (~30,000 of unit cells) and thickness of ~100 μm (~ 300 unit cells). These giant single crystals exhibit extraordinarily sharp photonic bandgaps with high reflectivity, long-range periodicity in all dimensions and well-defined lattice orientation.Conventional fabrication approaches for large-size three-dimensional photonic crystals are problematic. By properly controlling the self-assembly processes, the authors report the fabrication of monocrystalline blue phase liquid crystals that exhibit three-dimensional photonic-crystalline properties.

Predictive thermodynamic models for liquid--liquid extraction of single, binary and ternary lanthanides and actinides

International Nuclear Information System (INIS)

Hoh, Y.C.

1977-03-01

Chemically based thermodynamic models to predict the distribution coefficients and the separation factors for the liquid--liquid extraction of lanthanides-organophosphorus compounds were developed by assuming that the quotient of the activity coefficients of each species varies slightly with its concentrations, by using aqueous lanthanide or actinide complexes stoichiometric stability constants expressed as its degrees of formation, by making use of the extraction mechanism and the equilibrium constant for the extraction reaction. For a single component system, the thermodynamic model equations which predict the distribution coefficients, are dependent on the free organic concentration, the equilibrated ligand and hydrogen ion concentrations, the degree of formation, and on the extraction mechanism. For a binary component system, the thermodynamic model equation which predicts the separation factors is the same for all cases. This model equation is dependent on the degrees of formation of each species in their binary system and can be used in a ternary component system to predict the separation factors for the solutes relative to each other

Liquid Crystals for Nondestructive Evaluation

Science.gov (United States)

1978-09-01

polarizers (e.g., where p is the distance of alignment or pitch, X is the Nicol, Rochon, and Wollaston prisms ) are based upon peak wavelength of scattered...RANGE OF so 45" 45 - EVENT SEVENT T(°C) TEMPERATUJRE TC)4"TEMPERATURE 40RANGE OF T(°) 0-RANGE OF 40LIQUID ’ ൫" CRYSTAL S 36 3S. 30 0 IS 90 180 - I...Temperatures TI > T2 > - > TS defects was possible using the liquid crystal. are the Average TemperatursI Thes Resptivegi. Kapfer , Burns, Salvo, and Doyle

Liquid crystals in micron-scale droplets, shells and fibers

Science.gov (United States)

Urbanski, Martin; Reyes, Catherine G.; Noh, JungHyun; Sharma, Anshul; Geng, Yong; Subba Rao Jampani, Venkata; Lagerwall, Jan P. F.

2017-04-01

The extraordinary responsiveness and large diversity of self-assembled structures of liquid crystals are well documented and they have been extensively used in devices like displays. For long, this application route strongly influenced academic research, which frequently focused on the performance of liquid crystals in display-like geometries, typically between flat, rigid substrates of glass or similar solids. Today a new trend is clearly visible, where liquid crystals confined within curved, often soft and flexible, interfaces are in focus. Innovation in microfluidic technology has opened for high-throughput production of liquid crystal droplets or shells with exquisite monodispersity, and modern characterization methods allow detailed analysis of complex director arrangements. The introduction of electrospinning in liquid crystal research has enabled encapsulation in optically transparent polymeric cylinders with very small radius, allowing studies of confinement effects that were not easily accessible before. It also opened the prospect of functionalizing textile fibers with liquid crystals in the core, triggering activities that target wearable devices with true textile form factor for seamless integration in clothing. Together, these developments have brought issues center stage that might previously have been considered esoteric, like the interaction of topological defects on spherical surfaces, saddle-splay curvature-induced spontaneous chiral symmetry breaking, or the non-trivial shape changes of curved liquid crystal elastomers with non-uniform director fields that undergo a phase transition to an isotropic state. The new research thrusts are motivated equally by the intriguing soft matter physics showcased by liquid crystals in these unconventional geometries, and by the many novel application opportunities that arise when we can reproducibly manufacture these systems on a commercial scale. This review attempts to summarize the current understanding of

Liquid crystals in micron-scale droplets, shells and fibers

International Nuclear Information System (INIS)

Urbanski, Martin; Reyes, Catherine G; Noh, JungHyun; Sharma, Anshul; Geng, Yong; Subba Rao Jampani, Venkata; Lagerwall, Jan P F

2017-01-01

The extraordinary responsiveness and large diversity of self-assembled structures of liquid crystals are well documented and they have been extensively used in devices like displays. For long, this application route strongly influenced academic research, which frequently focused on the performance of liquid crystals in display-like geometries, typically between flat, rigid substrates of glass or similar solids. Today a new trend is clearly visible, where liquid crystals confined within curved, often soft and flexible, interfaces are in focus. Innovation in microfluidic technology has opened for high-throughput production of liquid crystal droplets or shells with exquisite monodispersity, and modern characterization methods allow detailed analysis of complex director arrangements. The introduction of electrospinning in liquid crystal research has enabled encapsulation in optically transparent polymeric cylinders with very small radius, allowing studies of confinement effects that were not easily accessible before. It also opened the prospect of functionalizing textile fibers with liquid crystals in the core, triggering activities that target wearable devices with true textile form factor for seamless integration in clothing. Together, these developments have brought issues center stage that might previously have been considered esoteric, like the interaction of topological defects on spherical surfaces, saddle-splay curvature-induced spontaneous chiral symmetry breaking, or the non-trivial shape changes of curved liquid crystal elastomers with non-uniform director fields that undergo a phase transition to an isotropic state. The new research thrusts are motivated equally by the intriguing soft matter physics showcased by liquid crystals in these unconventional geometries, and by the many novel application opportunities that arise when we can reproducibly manufacture these systems on a commercial scale. This review attempts to summarize the current understanding of

Tunable photoluminescence of porous silicon by liquid crystal infiltration

International Nuclear Information System (INIS)

Ma Qinglan; Xiong Rui; Huang Yuanming

2011-01-01

The photoluminescence (PL) of porous silicon films has been investigated as a function of the amount of liquid crystal molecules that are infiltrated into the constricted geometry of the porous silicon films. A typical nematic liquid crystal 4-pentyl-4'-cyanobiphenyl was employed in our experiment as the filler to modify the PL of porous silicon. It is found that the originally red PL of porous silicon films can be tuned to blue by simply adjusting the amount of liquid crystal molecules in the microchannels of the porous films. The chromaticity coordinates are calculated for the recorded PL spectra. The mechanism of the tunable PL is discussed. Our results have demonstrated that the luminescent properties of porous silicon films can be efficiently tuned by liquid crystal infiltration. - Highlights: → Liquid crystal infiltration can tune the photoluminescence of porous silicon. → Red emission of porous silicon can be switched to blue by the infiltration. → Chromaticity coordinates are calculated for the tuned emissions. → White emission is realized for porous silicon by liquid crystal infiltration.

Liquid Crystals in Tribology

Directory of Open Access Journals (Sweden)

María-Dolores Bermúdez

2009-09-01

Full Text Available Two decades ago, the literature dealing with the possible applications of low molar mass liquid crystals, also called monomer liquid crystals (MLCs, only included about 50 references. Today, thousands of papers, conference reports, books or book chapters and patents refer to the study and applications of MLCs as lubricants and lubricant additives and efforts are made to develop new commercial applications. The development of more efficient lubricants is of paramount technological and economic relevance as it is estimated that half the energy consumption is dissipated as friction. MLCs have shown their ability to form ordered boundary layers with good load-carrying capacity and to lower the friction coefficients, wear rates and contact temperature of sliding surfaces, thus contributing to increase the components service life and to save energy. This review includes the use of MLCs in lubrication, and dispersions of MLCs in conventional polymers (PDMLCs. Finally, new lubricating system composed of MLC blends with surfactants, ionic liquids or nanophases are considered.

Liquid crystals in tribology.

Science.gov (United States)

Carrión, Francisco-José; Martínez-Nicolás, Ginés; Iglesias, Patricia; Sanes, José; Bermúdez, María-Dolores

2009-09-18

Two decades ago, the literature dealing with the possible applications of low molar mass liquid crystals, also called monomer liquid crystals (MLCs), only included about 50 references. Today, thousands of papers, conference reports, books or book chapters and patents refer to the study and applications of MLCs as lubricants and lubricant additives and efforts are made to develop new commercial applications. The development of more efficient lubricants is of paramount technological and economic relevance as it is estimated that half the energy consumption is dissipated as friction. MLCs have shown their ability to form ordered boundary layers with good load-carrying capacity and to lower the friction coefficients, wear rates and contact temperature of sliding surfaces, thus contributing to increase the components service life and to save energy. This review includes the use of MLCs in lubrication, and dispersions of MLCs in conventional polymers (PDMLCs). Finally, new lubricating system composed of MLC blends with surfactants, ionic liquids or nanophases are considered.

Tunable bandpass filter based on photonic crystal fiber filled with multiple liquid crystals

DEFF Research Database (Denmark)

Scolari, Lara; Tartarini, G.; Borelli, E.

2007-01-01

A tunable bandpass filter based on a photonic crystal fiber filled with two different liquid crystals is demonstrated. 130 nm bandwidth tunability is achieved by tuning the temperature from 30degC to 90degC.......A tunable bandpass filter based on a photonic crystal fiber filled with two different liquid crystals is demonstrated. 130 nm bandwidth tunability is achieved by tuning the temperature from 30degC to 90degC....

Simulation of liquid crystals. Disclinations and surface modification

International Nuclear Information System (INIS)

Downton, M.

2001-01-01

In this thesis we investigate the behaviour of molecular models liquid crystals in several different situations. Basic introductory material on liquid crystals and computer simulations is discussed in the first two chapters, we then discuss the research. The third chapter investigates the interaction between a liquid crystal and a modified surface. A confined system of hard spherocylinders in a slab geometry is examined. The surface consists of planar hard walls with elongated molecules grafted perpendicularly onto them. The concentration of grafted molecules is varied to give different surfaces. Several different behaviours are found including planar, homeotropic and tilted anchorings of the liquid crystal. Molecular dynamics simulations of a nematic liquid crystal in slab geometry with twisted boundary conditions are performed. By arranging the initial configuration suitably it is possible to create a simulation cell with two regions of opposite twist separated by a strength half disclination line. The properties of the line are examined both with and without an applied external field. Finally, we again examine the system of grafted molecules on a flat substrate using an atomistic model of both the liquid crystal and the surface molecules. Again the effect of varying the density of grafted molecules is found to change the anchoring characteristics of the surface; both homeotropic and planar anchorings are observed. (author)

Determination and thermodynamic modeling of solid–liquid phase equilibrium for 3,5-dichloroaniline in pure solvents and ternary 3,5-dichloroaniline + 1,3,5-trichlorobenzene + toluene system

International Nuclear Information System (INIS)

Li, Rongrong; Du, Cunbin; Meng, Long; Han, Shuo; Wang, Jian; Zhao, Hongkun

2016-01-01

Highlights: • Solubility of 3,5-dichloroaniline in seven organic solvents were determined. • Solid–liquid phase equilibrium for ternary system was measured. • The binary and ternary phase diagrams were constructed. • The phase diagrams were correlated with thermodynamic models. - Abstract: The solid–liquid phase equilibrium data for 3,5-dichloroaniline in n-propanol, isopropanol, n-butanol, isobutanol, toluene, ethyl acetate and acetone at (283.15 to 308.15) K were determined experimentally by gas chromatography under 101.3 kPa. The solubility of 3,5-dichloroaniline in these solvents decreased according to the following order: ethyl acetate > (acetone, toluene) for the solvents of ethyl acetate, acetone, and toluene; and for the other solvents, (isopropanol, n-butanol) > n-propanol > isobutanol. According to the solubility of 3,5-dichloroaniline in pure solvents, the solid–liquid phase equilibrium for the ternary mixture of 3,5-dichloroaniline + 1,3,5-trichlorobenzene + toluene were measured by using an isothermal saturation method at three temperatures of 283.15, 293.15, and 303.15 K under 101.3 kPa, and the corresponding isothermal phase diagrams were constructed. Two pure solids were formed in the ternary system at a fixed temperature, which were pure 3,5-dichloroaniline and pure 1,3,5-trichlorobenzene and were identified by Schreinemakers’ method of wet residue. The temperature dependence of 3,5-dichloroaniline solubility in pure solvents was correlated by the modified Apelblat equation, λh equation, Wilson model and NRTL model; and the ternary solid–liquid phase equilibrium of 3,5-dichloroaniline + 1,3,5-trichlorobenzene + toluene were described by the Wilson model and NRTL model. Results showed that calculated solubility values with these models agreed well with the experimental ones for the studied binary and ternary systems. The solid–liquid equilibrium and the thermodynamic models for the binary and ternary systems can offer the

Liquid Crystal photonic Bandgap Fiber Devices

DEFF Research Database (Denmark)

Wei, Lei

In this Ph.D. thesis, an experimental investigation of liquid crystal photonic bandgap (LCPBG) fiber devices and applications is presented. Photonic crystal fibers (PCFs) consist of a cladding microstructure with periodic index variations and a core defined by a defect of the structure. The prese......In this Ph.D. thesis, an experimental investigation of liquid crystal photonic bandgap (LCPBG) fiber devices and applications is presented. Photonic crystal fibers (PCFs) consist of a cladding microstructure with periodic index variations and a core defined by a defect of the structure...... of each LCPBG fiber. Finally, the applications for LCPBG fiber devices based on the on-chip platform design have been demonstrated in realizing microwave true-time delay and creating an electrically tunable fiber laser. Referatet mailes...

Extensive Evaluation of the Conductor-like Screening Model for Real Solvents Method in Predicting Liquid-Liquid Equilibria in Ternary Systems of Ionic Liquids with Molecular Compounds.

Science.gov (United States)

Paduszyński, Kamil

2018-04-12

A conductor-like screening model for real solvents (COSMO-RS) is nowadays one of the most popular and commonly applied tools for the estimation of thermodynamic properties of complex fluids. The goal of this work is to provide a comprehensive review and analysis of the performance of this approach in calculating liquid-liquid equilibrium (LLE) phase diagrams in ternary systems composed of ionic liquid and two molecular compounds belonging to diverse families of chemicals (alkanes, aromatics, S/N-compounds, alcohols, ketones, ethers, carboxylic acid, esters, and water). The predictions are presented for extensive experimental database, including 930 LLE data sets and more than 9000 data points (LLE tie lines) reported for 779 unique ternary mixtures. An impact of the type of molecular binary subsystem on the accuracy of predictions is demonstrated and discussed on the basis of representative examples. The model's capability of capturing qualitative trends in the LLE distribution ratio and selectivity is also checked for a number of structural effects. Comparative analysis of two levels of quantum chemical theory (BP-TZVP-COSMO vs BP-TZVPD-FINE) for the input molecular data for COSMO-RS is presented. Finally, some general recommendations for the applicability of the model are indicated based on the analysis of the global performance as well as on the results obtained for systems relevant from the point of view of important separation problems.

Liquid crystal colloids

CERN Document Server

Muševič, Igor

2017-01-01

This book brings together the many concepts and discoveries in liquid crystal colloids contributed over the last twenty years and scattered across numerous articles and book chapters. It provides both a historical overview of the development of the field and a clear perspective on the future applications in photonics. The book covers all phenomena observed in liquid crystal colloids with an emphasis on experimental tools and applications of topology in condensed matter, as well as practical micro-photonics applications. It includes a number of spectacular manifestations of new topological phenomena not found or difficult to observe in other systems. Starting from the early works on nematic colloids, it explains the basics of topological defects in ordered media, charge and winding, and the elastic forces between colloidal particles in nematics. Following a detailed description of experimental methods, such as optical tweezing and particle tracking, the book eases the reader into the theoretical part, which de...

Study of thermal properties and the effect of carrier concentration in the ternary compound Ag6Ge10P12

International Nuclear Information System (INIS)

Ahmad, K.A.

1990-01-01

In this work the thermal properties of the ternary semiconducting compounds (Ag6Ge10P12) have been investigated. Single crystal samples prepared by Bridgman technique low temperature cryostat are illustrated which is suitable to control temperature from liquid nitrogen up to room temperature. The work contains theoretical and experimental study on binary and ternary semiconductors. Also it illustrates the experimental results of thermoelectric properties of AG6Ge10P12 samples as well as the calculated effective mass, Fermi energy and their analysis throughout the temperature range between 80-300 K. 3 tabs.; 18 figs.; 57 refs

Liquid crystals beyond displays chemistry, physics, and applications

CERN Document Server

Li, Quan

2012-01-01

The chemistry, physics, and applications of liquid crystals beyond LCDs Liquid Crystals (LCs) combine order and mobility on a molecular and supramolecular level. But while these remarkable states of matter are most commonly associated with visual display technologies, they have important applications for a variety of other fields as well. Liquid Crystals Beyond Displays: Chemistry, Physics, and Applications considers these, bringing together cutting-edge research from some of the most promising areas of LC science. Featuring contributions from respected researchers from around the globe, th

Liquid nitrogen dewar for protein crystal growth

Science.gov (United States)

2001-01-01

Gaseous Nitrogen Dewar apparatus developed by Dr. Alex McPherson of the University of California, Irvine for use aboard Mir and the International Space Station allows large quantities of protein samples to be crystallized in orbit. The specimens are contained either in plastic tubing (heat-sealed at each end). Biological samples are prepared with a precipitating agent in either a batch or liquid-liquid diffusion configuration. The samples are then flash-frozen in liquid nitrogen before crystallization can start. On orbit, the Dewar is placed in a quiet area of the station and the nitrogen slowly boils off (it is taken up by the environmental control system), allowing the proteins to thaw to begin crystallization. The Dewar is returned to Earth after one to four months on orbit, depending on Shuttle flight opportunities. The tubes then are analyzed for crystal presence and quality

Fundamentals of liquid crystal devices

CERN Document Server

Yang, Deng-Ke

2014-01-01

Revised throughout to cover the latest developments in the fast moving area of display technology, this 2nd edition of Fundamentals of Liquid Crystal Devices, will continue to be a valuable resource for those wishing to understand the operation of liquid crystal displays. Significant updates include new material on display components, 3D LCDs and blue-phase displays which is one of the most promising new technologies within the field of displays and it is expected that this new LC-technology will reduce the response time and the number of optical components of LC-modules. Prof. Yang is a pion

Experimental investigation of phase equilibria in the Co-W-V ternary system

International Nuclear Information System (INIS)

Liu Xingjun; Zhu Yihong; Yu Yan; Wang Cuiping

2011-01-01

Highlights: → Three isothermal sections of the Co-W-V ternary system at 1100 deg. C, 1200 deg. C and 1300 deg. C were determined. → No ternary compound was found in the Co-W-V ternary system. → A stable liquid miscibility gap is newly discovered in the Co-W-V ternary system. → This work is of great essence to establish the thermodynamic database for the Co-based alloys. - Abstract: The phase equilibria in the Co-W-V ternary system were experimentally investigated by optical microscopy (OM), electron probe microanalysis (EPMA) and X-ray diffraction (XRD) on the equilibrated alloys. Three isothermal sections of the Co-W-V ternary system at 1100 deg. C, 1200 deg. C and 1300 deg. C were determined, and no ternary compound was found in this system. In addition, a novel phenomena induced by the liquid phase separation in the Co-W-V alloys was firstly discovered, suggesting that a stable liquid miscibility gap exists in the Co-W-V ternary system. The newly determined phase equilibria and firstly discovered phase separation phenomena in the Co-W-V system will provide important information for the development of Co-W based alloys.

Study on the properties of tunable prohibited band gaps for one-dimensional ternary magnetized plasma photonic crystals

International Nuclear Information System (INIS)

Zhang Haifeng; Zheng Jianping; Zhu Rongjun

2012-01-01

The transfer matrix method was applied to study on the properties of tunable prohibited band gaps for one-dimensional ternary magnetized plasma photonic crystals with TE wave arbitrary incident under ideal conditions. TE wave would be divided into left-handed circularly polarized wave and right-handed circularly polarized wave after propagation through one-dimensional ternary magnetized plasma photonic crystals. The calculated transmission coefficients were used to analyze the effects of parameter of plasma, plasma filling factor, incident angle and relative dielectric constant for dielectric layer on the properties of tunable prohibited band gap. The results illustrate that the width of band gaps can not be broadened by increasing plasma collision frequency, the numbers and width of band gaps can be tuned by changing plasma frequency, plasma filling factor and relative dielectric constant for dielectric layer. The band gaps for right-handed circularly polarized wave can be tuned by the plasma gyro frequency, but band gaps for the left-handed circularly polarized wave can't influenced. Low-frequency region of band gaps will be broadened, while high-frequency region of band gaps will be firstly narrow and then broaden with increasing incident angle. (authors)

Experimental measurements of vapor-liquid equilibria of the H2O + CO2 + CH4 ternary system

Science.gov (United States)

Qin, J.; Rosenbauer, R.J.; Duan, Zhenhao

2008-01-01

Reported are the experimental measurements on vapor-liquid equilibria in the H2O + CO2 + CH4 ternary system at temperatures from (324 to 375) K and pressures from (10 to 50) MPa. The results indicate that the CH4 solubility in the ternary mixture is about 10 % to 40 % more than that calculated by interpolation from the Henry's law constants of the binary system, H2O + CH4, and the solubility of CO2 is 6 % to 20 % more than what is calculated by the interpolation from the Henry's law constants of the binary mixture, H 2O + CO2. ?? 2008 American Chemical Society.

Sc-W-Si and Sc-W-Ge ternary systems

International Nuclear Information System (INIS)

Kotur, B.Ya.; Voznyak, O.M.; Bodak, O.I.

1989-01-01

Phase equilibria in Sc-W-Si and Sc-W-Ge ternary systems are investigated at 1070 K. Sc 2+x W 3-x Si 4 ternary compound (0≤x≤1) is determined, its crystal structure (Ce 2 Sc 3 Si 4 structural type), as well as, change of elementary cell parameters and microhardness within homogeneity range are determined. Regularities of component interaction within Sc-M-Si(Ge) (M-Cr, Mo, W) ternary system are determined. Ternary systems with Mo and W are more closer to each other according to the phase equilibria character, than to ternary systems with Cr

Lyotropic chromonic liquid crystals: From viscoelastic properties to living liquid crystals

Science.gov (United States)

Zhou, Shuang

Lyotropic chromonic liquid crystal (LCLC) represents a broad range of molecules, from organic dyes and drugs to DNA, that self-assemble into linear aggregates in water through face-to-face stacking. These linear aggregates of high aspect ratio are capable of orientational order, forming, for example nematic phase. Since the microscopic properties (such as length) of the chromonic aggregates are results of subtle balance between energy and entropy, the macroscopic viscoelastic properties of the nematic media are sensitive to change of external factors. In the first part of this thesis, by using dynamic light scattering and magnetic Frederiks transition techniques, we study the Frank elastic moduli and viscosity coefficients of LCLC disodium cromoglycate (DSCG) and sunset yellow (SSY) as functions of concentration c , temperature T and ionic contents. The elastic moduli of splay (K1) and bend (K3) are in the order of 10pN, about 10 times larger than the twist modulus (K2). The splay modulus K1 and the ratio K1/K3 both increase substantially as T decreases or c increases, which we attribute to the elongation of linear aggregates at lower T or higher c . The bend viscosity is comparable to that of thermotropic liquid crystals, while the splay and twist viscosities are several orders of magnitude larger, changing exponentially with T . Additional ionic additives into the system influence the viscoelastic properties of these systems in a dramatic and versatile way. For example, monovalent salt NaCl decreases bend modulus K3 and increases twist viscosity, while an elevated pH decreases all the parameters. We attribute these features to the ion-induced changes in length and flexibility of building units of LCLC, the chromonic aggregates, a property not found in conventional thermotropic and lyotropic liquid crystals form by covalently bound units of fixed length. The second part of the thesis studies a new active bio-mechanical hybrid system called living liquid crystal

Molecular dynamics simulations of liquid crystals at interfaces

International Nuclear Information System (INIS)

Shield, Mark

2002-01-01

Molecular dynamics simulations of an atomistic model of 4-n-octyl-4'-cyanobiphenyl (8CB) were performed for thin films of 8CB on solid substrates (a pseudopotential representation of the molecular topography of the (100) crystal surface of polyethylene (PE), a highly ordered atomistic model of a pseudo-crystalline PE surface and an atomistic model of a partially orientated film of PE), free standing thin films of 8CB and 8CB droplets in a hexagonal pit. The systems showed strong homeotropic anchoring at the free volume interface and planar anchoring at the solid interface whose strength was dependent upon the surface present. The free volume interface also demonstrated weak signs of smectic wetting of the bulk. Simulations of thin free standing films of liquid crystals showed the ordered nature of the liquid crystals at the two free volume interfaces can be adopted by the region of liquid crystal molecules between the homeotropic layer at each interface only if there is a certain number of liquid crystal molecules present. The perpendicular anchoring imposed by the free volume interface and the solid interface for the thin films on the solid substrates resulted in some evidence for the liquid crystal director undergoing a continual rotation at low temperatures and a definite discontinuous change at higher temperatures. The liquid crystal alignment imparted by these substrates was found to depend upon the topography of the surface and not the direction of the polymer chains in the substrate. The liquid crystal was found to order via an epitaxy-like mechanism. The perpendicular anchoring results in a drop in the order - disorder transition temperature for the molecules in the region between the homeotropic layer at the free volume interface and the planar layers at the solid interface. An increase in the size of this region does not alter the transition temperature. The shape of the liquid crystal molecules is dependent upon the degree of order and thus the nematic

Modeling of the branching influence on liquid–liquid equilibrium of binary and ternary polymer solutions by lattice–cluster theory

International Nuclear Information System (INIS)

Browarzik, Dieter; Langenbach, Kai; Enders, Sabine; Browarzik, Christina

2013-01-01

Highlights: ► Liquid–liquid equilibrium (LLE) is calculated with the lattice–cluster theory (LCT). ► Equations of the LCT are reduced to only three geometrical parameters. ► Branching influence on the LLE is modeled for binary and ternary polymer solutions. ► Branched and linear solvents and polymers are compared in their influence on LLE. ► Solutions of branched polymers in branched solvents show the best miscibility. -- Abstract: The liquid–liquid equilibrium (LLE) of ternary model systems of the type solvent A + polymer B + solvent C is treated in the framework of lattice–cluster theory (LCT). There are a linear and a branched type of A-molecules as well as a linear and two types of strongly branched polymer molecules. The C-molecules are assumed to occupy only one lattice site. For nine binary and six ternary polymer solutions the branching influence on LLE is discussed. Currently, the LCT is the most useful model to take the architecture of the molecules into account. However, particularly for ternary systems the model is not comfortable because of the very numerous terms of the Gibbs energy. Using some relationships between the geometrical parameters of the model a considerable simplification is possible. In this paper the new and simpler equations of the LCT are presented. For comparison with experimental data critical temperatures of solutions of linear and branched polyethylene samples in diphenyl ether are calculated

Liquid crystal display

International Nuclear Information System (INIS)

Takami, K.

1981-01-01

An improved liquid crystal display device is described which can display letters, numerals and other necessary patterns in the night time using a minimized amount of radioactive material. To achieve this a self-luminous light source is placed in a limited region corresponding to a specific display area. (U.K.)

Ebulliometric determination and prediction of (vapor + liquid) equilibria for binary and ternary mixtures containing alcohols (C{sub 1}-C{sub 4}) and dimethyl carbonate

Energy Technology Data Exchange (ETDEWEB)

Matsuda, Hiroyuki, E-mail: matsuda@chem.cst.nihon-u.ac.jp [Department of Materials and Applied Chemistry, Nihon University, 1-8 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Fukano, Makoto; Kikkawa, Shinichiro [Department of Materials and Applied Chemistry, Nihon University, 1-8 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Constantinescu, Dana [Carl von Ossietzky Universitaet Oldenburg, Technische Chemie, D-26111 Oldenburg (Germany); Kurihara, Kiyofumi; Tochigi, Katsumi; Ochi, Kenji [Department of Materials and Applied Chemistry, Nihon University, 1-8 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Gmehling, Juergen [Carl von Ossietzky Universitaet Oldenburg, Technische Chemie, D-26111 Oldenburg (Germany)

2012-01-15

Highlights: > The VLE behavior of systems containing dimethyl carbonate (DMC) was investigated. > VLE data for ternary and binary mixtures containing alcohol and DMC were measured. > Several activity coefficient models were used for data reduction or prediction. > Valley line, i.e., distillation boundary, was observed for the ternary mixture. > Residue curves were calculated to investigate composition profile for distillation. - Abstract: (Vapor + liquid) equilibrium (VLE) data for a ternary mixture, namely {l_brace}methanol + propan-1-ol + dimethyl carbonate (DMC){r_brace}, and four binary mixtures, namely an {l_brace}alcohol (C{sub 3} or C{sub 4}) + DMC{r_brace}, containing the binary constituent mixtures of the ternary mixture, were measured at p = (40.00 to 93.32) kPa using a modified Swietoslawski-type ebulliometer. The experimental data for the binary systems were correlated using the Wilson model. The Wilson model was also applied to the ternary system to predict the VLE behavior using parameters from the binary mixtures. The modified UNIFAC (Dortmund) model was also tested for the predictions of the VLE behavior of the binary and ternary mixtures. In addition, the experimental VLE data for the ternary and constituent binary mixtures were correlated using the extended Redlich-Kister (ERK) model, which can completely represent the azeotropic points. For the ternary system, a comparison of the experimental and the predicted or correlated boiling points obtained using the Wilson and ERK models showed that the ERK model is more accurate. The valley line, i.e., the curve which divides the patterns of vapor-liquid tie lines, was found in the (methanol + propan-1-ol + DMC) system. This valley line could be represented by the ERK model. Finally, the composition profile for simple distillation of this ternary mixture was obtained by analysis of the residue curves from the estimated Wilson parameters of the constituent binary mixtures.

Development of Cu-Hf-Al ternary systems and tungsten wire/particle reinforced Cu48Hf43Al9 bulk metallic glass composites for strengthening

International Nuclear Information System (INIS)

Park, Joyoung; An, Jihye; Choi-Yim, Haein

2010-01-01

Stable bulk glass forming alloys can be developed over a wide range of compositions in Cu-Hf-Al ternary systems starting from the Cu 49 Hf 42 Al 9 bulk metallic glass. Ternary Cu-Hf-Al alloys can be cast directly from the melt into copper molds to form fully amorphous strips with thicknesses of 1 to 6 mm. The maximum critical diameter of the new Cu-Hf-Al ternary alloy was 6 mm. X-ray diffraction patterns were used to confirm the amorphous nature of the ternary Cu-Hf-Al alloys. To increase the toughness of these metallic glasses, we reinforced the Cu 48 Hf 43 Al 9 bulk metallic glass-forming liquid with a 50% volume fraction of tungsten particles and an 80% volume fraction of tungsten wires with diameters of 242.4 μm. Composites with a critical diameter of 7 mm and length 70 mm were synthesized. The structure of the composites was confirmed by using X-ray diffraction (XRD), and the scanning electron microscopy (SEM). The mechanical properties of the composites were studied in compression tests. The thermal stability and the crystallization processes of the Cu-Hf-Al alloys and composites were investigated by using differential scanning calorimetry (DSC). Values of the glass transition temperature (T g ), the crystallization temperature (T x ), and the supercooled liquid region (ΔT = T x - T g ) are given in this paper.

Small-angle neutron scattering technique in liquid crystal studies

International Nuclear Information System (INIS)

Shahidan Radiman

2005-01-01

The following topics discussed: general principles of SAS (Small-angle Neutron Scattering), liquid crystals, nanoparticle templating on liquid crystals, examples of SAS results, prospects of this studies

Optical Power Limiting Liquid Crystal Composites

Science.gov (United States)

1994-11-10

materials. In addition to the nonlinear studies, a separate subproject involving linear properties 0 of polymer dispersed liquid crystals in the infrared ...The horizontal axis represents on-axis laser intensity Io, defined as Io = 2P/( ww2 ), where P is the power and u0 is the beam waist. As can be seen in...I * 9 IR Shutter 1 Included in our original contract was a separate project to evaluate the use of liquid crystal composites in infrared shattering

muSR-Investigation of a Liquid Crystal Containing Iron Atoms

CERN Document Server

Mamedov, T N; Galyametdinov, Yu G; Gritsaj, K I; Herlach, D; Kormann, O; Major, J V; Rochev, V Ya; Stoikov, A V; Zimmermann, U

2000-01-01

The work is devoted to the investigation of properties of a liquid crystal whose molecule contains iron atom. The compounds of this type are of interest from the point of view of obtaining liquid crystals with magnetic properties. The temperature dependence of the polarization and relaxation rate of positive muon spin in the liquid crystal was measured in the temperature range 4-300 K. The results obtained do not contradict the suggestion that the iron ions from an antiferromagnetically-ordered structure in this liquid crystal at the temperatures below 80 K.

Electrically modulated transparent liquid crystal-optical grating projection

DEFF Research Database (Denmark)

Buss, Thomas; Smith, Cameron; Kristensen, Anders

2013-01-01

A transparent, fully integrated electrically modulated projection technique is presented based on light guiding through a thin liquid crystal layer covering sub-wavelength gratings. The reported device operates at 10 V with response times of 4.5 ms. Analysis of the liquid crystal alignment shows...

Liquid-crystal intraocular adaptive lens with wireless control

NARCIS (Netherlands)

Simonov, A.N.; Vdovine, G.V.; Loktev, M.

2007-01-01

We present a prototype of an adaptive intraocular lens based on a modal liquid-crystal spatial phase modulator with wireless control. The modal corrector consists of a nematic liquid-crystal layer sandwiched between two glass substrates with transparent low- and high-ohmic electrodes, respectively.

Soap, science, and flat-screen TVs a history of liquid crystals

CERN Document Server

Dunmur, David

2011-01-01

The terms 'liquid crystal' or 'liquid crystal display' (LCD) are well-known in the context of flat-screen televisions, but the properties and history of liquid crystals are little understood. This book tells the story of liquid crystals, from their controversial discovery at the end of the nineteenth century, to their eventual acceptance as another state of matter to rank alongside gases, liquids and solids. As their story unfolds, the scientists involved and their works are put into illuminating broader socio-political contexts. In recent years, liquid crystals have had a major impact on the display industry, culminating in the now widely available flat-screen televisions; this development is described in detail over three chapters, and the basic science behind it is explained in simple terms accessible to a general reader. New applications of liquid crystals in materials, bio-systems, medicine and technology are also explained.

The crystal structure of a new ternary antimonide: TmCu4-xSb2 (x 1.065)

International Nuclear Information System (INIS)

Fedyna, L.O.; Bodak, O.I.; Fedorchuk, A.O.; Tokaychuk, Ya.O.

2005-01-01

The crystal structure of the new ternary compound TmCu 4-x Sb 2 (x 1.065) was determined by direct methods from X-ray powder data (diffractometer DRON-3M, Cu Kα-radiation). It crystallizes with the orthorhombic structure type ErFe 4 Ge 2 (low-temperature modification) and is the first representative of this structure type among known antimonides: space group Pnnm, Pearson code oP14-2.13, a = 7.00565(6) A, b = 7.83582(6) A, c = 4.25051(3) A, Z = 2. Investigated structure is an orthorhombically deformed derivative of the ZrFe 4 Si 2 structure type

Large Electro-Optic Kerr-Effect in Ionic Liquid Crystals: Connecting Features of Liquid Crystals and Polyelectrolytes.

Science.gov (United States)

Schlick, Michael Christian; Kapernaum, Nadia; Neidhardt, Manuel; Wöhrle, Tobias; Stöckl, Yannick; Laschat, Sabine; Gießelmann, Frank

2018-06-06

The electro-optic Kerr effect in the isotropic phase of two ionic liquid crystals (ILCs) is investigated and compared to the Kerr effect in non-ionic liquid crystals (LCs) with same phase sequences, namely direct isotropic to hexagonal columnar transitions and direct isotropic to smectic-A transitions. Up to electric field amplitudes of some 106 V m-1, the optical birefringence induced in the isotropic phases follows Kerr's law and strongly increases when the temperature approaches the transition temperature into the particular liquid crystalline phase. Close to the transition, maximum Kerr constants in the order of 10-11 m V-2 are found, which are more than ten times higher than the Kerr constant of nitrobenzene, a strongly dipolar fluid with a huge Kerr effect applied in optical shutters and phase modulators. In comparison to their non-ionic LC counterparts the Kerr effect in ILCs is found to be enhanced in magnitude, but slowed-down in speed, showing rise times in the order of ten milliseconds. These remarkable differences are attributed to the presence of counterion polarization well-known from complex ionic fluids such as polyelectrolytes or ionic micellar solutions. ILCs thus combine the Kerr effect features of liquid crystals and complex ionic fluids. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Constitution of the ternary system Cr–Ni–Ti

International Nuclear Information System (INIS)

Krendelsberger, Natalja; Weitzer, Franz; Du, Yong; Schuster, Julius C.

2013-01-01

Highlights: •Reaction scheme and liquidus surface for Cr-Ni-Ti are given. •In the ternary the C14-type Laves phase coexists with the liquid phase. •Two ternary eutectics are identified. -- Abstract: The nature of solid–liquid phase equilibria in the ternary system Cr–Ni–Ti was investigated using electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and differential thermal analysis. Literature data on solid state phase equilibria are confirmed. The Cr 2 Ti Laves phase modifications coexisting with Ni–Ti phases are clarified to be hexagonal C14-type and cubic C15-type. The C14-type Laves phase γCr 2 Ti is found to coexist with the liquid phase. It forms in the pseudobinary peritectic reaction p max1 from L + β(Cr,Ti) at 1389 °C. On further cooling γCr 2 Ti + NiTi solidify at 1202 °C in the pseudobinary eutectic e max2 . In the Cr-rich part of the system ternary eutectics occur at 1216 °C (E 1 : L = Ni 3 Ti + (Ni) + β(Cr,Ti)) and 1100 °C (E 2 : L = NiTi + Ni 3 Ti + β(Cr,Ti)), respectively. No ternary eutectic is found in the Ti-rich part. Rather the eutectic trough ends in the binary eutectic L = NiTi 2 + β(Ti)

UV response on dielectric properties of nano nematic liquid crystal

Directory of Open Access Journals (Sweden)

Kamal Kumar Pandey

2018-03-01

Full Text Available In this work, we investigate the effect of UV light irradiation on the dielectric parameters of nematic liquid crystal (5CB and ZnO nanoparticles dispersed liquid crystal. With addition of nanoparticles in nematic LC are promising new materials for a variety of application in energy harvesting, displays and photonics including the liquid crystal laser. To realize many applications, however we optimize the properties of liquid crystal and understand how the UV light irradiation interact the nanoparticles and LC molecules in dispersed/doped LC. The dielectric permittivity and loss factor have discussed the pure nematic LC and dispersed/doped system after, during and before UV light exposure. The dielectric relaxation spectroscopy was carried out in the frequency range 100 Hz–10 MHz in the nematic mesophase range. Keywords: Dielectric permittivity, Relaxation frequency, Nematic liquid crystal, UV light irradiation

Liquid crystals: a new topic in physics for undergraduates

International Nuclear Information System (INIS)

Pavlin, Jerneja; Čepič, Mojca; Vaupotič, Nataša

2013-01-01

This paper presents a teaching module about liquid crystals. Since liquid crystals are linked to everyday student experiences and are also a topic of current scientific research, they are an excellent candidate for a modern topic to be introduced into education. We show that liquid crystals can provide a pathway through several fields of physics such as thermodynamics, optics and electromagnetism. We discuss what students should learn about liquid crystals and what physical concepts they should know before considering them. In the presentation of the teaching module, which consists of a lecture and experimental work in a chemistry and physics laboratory, we focus on experiments on phase transitions, polarization of light, double refraction and colours. A pilot evaluation of the module was performed among pre-service primary school teachers who have no special preference for natural sciences. The evaluation shows that the module is very efficient in transferring knowledge. A prior study showed that the informally obtained pre-knowledge on liquid crystals of the first-year students from several different fields of study was negligible. Since social science students are the least interested in natural sciences, it can be expected that students in any study programme will on average achieve at least as good qualitative knowledge of phenomena related to liquid crystals as the group involved in the pilot study. (paper)

Young-Laplace equation for liquid crystal interfaces

Science.gov (United States)

Rey, Alejandro D.

2000-12-01

This letter uses the classical theories of liquid crystal physics to derive the Young-Laplace equation of capillary hydrostatics for interfaces between viscous isotropic (I) fluids and nematic liquid crystals (NLC's), and establishes the existence of four energy contributions to pressure jumps across these unusual anisotropic interfaces. It is shown that in addition to the usual curvature contribution, bulk and surface gradient elasticity, elastic stress, and anchoring energy contribute to pressure differentials across the interface. The magnitude of the effect is proportional to the elastic moduli of the NLC, and to the bulk and surface orientation gradients that may be present in the nematic phase. In contrast to the planar interface between isotropic fluids, flat liquid crystal interfaces support pressure jumps if elastic stresses, bulk and surface gradient energy, and/or anchoring energies are finite.

H-Bond stabilized columnar discotic liquid crystals

NARCIS (Netherlands)

Paraschiv, I.

2007-01-01

Since 1977, more than 2300 publications on discotic (disk-like) liquid crystalline materials have appeared. Discotic liquid crystals, which usually consist of polyaromatic molecules surrounded by long peripheral alkyl tails, can form liquid crystalline mesophases in a wide temperature range. Within

Thermodynamic mixing effects of liquid ternary Au–Fe–Pd alloys by computer-aided Knudsen cell mass spectrometry

International Nuclear Information System (INIS)

Tomiska, Josef

2012-01-01

Highlights: ► Thermodynamic mixing behavior of liquid Au–Fe–Pd alloys over the whole range of composition. ► Experimental investigations by means of the computer-aided Knudsen cell mass spectrometry. ► Algebraic representation of the molar excess properties by TAP series concept. ► The corresponding TAP parameters are presented. ► The values of all molar excess functions, and thermodynamic activities at 1850 K are given. - Abstract: Thermodynamic investigations on liquid ternary Au–Fe–Pd alloys have been performed by means of the computer-aided Knudsen cell mass spectrometry. The “Digital Intensity-Ratio” (DIR) – method has been applied for the determination of the thermodynamic mixing behaviour. The ternary thermodynamically adapted power (TAP) series concept is used for the algebraic representation of the molar excess properties. The corresponding TAP parameters, and the values of the molar excess quantities Z E (Z = Gibbs energy G, heat of mixing H, and entropy S) as well as the thermodynamic activities of all three constituents at 1850 K are presented.

Hydrothermal decomposition of liquid crystal in subcritical water

International Nuclear Information System (INIS)

Zhuang, Xuning; He, Wenzhi; Li, Guangming; Huang, Juwen; Lu, Shangming; Hou, Lianjiao

2014-01-01

Highlights: • Hydrothermal technology can effectively decompose the liquid crystal of 4-octoxy-4'-cyanobiphenyl. • The decomposition rate reached 97.6% under the optimized condition. • Octoxy-4'-cyanobiphenyl was mainly decomposed into simple and innocuous products. • The mechanism analysis reveals the decomposition reaction process. - Abstract: Treatment of liquid crystal has important significance for the environment protection and human health. This study proposed a hydrothermal process to decompose the liquid crystal of 4-octoxy-4′-cyanobiphenyl. Experiments were conducted with a 5.7 mL stainless tube reactor and heated by a salt-bath. Factors affecting the decomposition rate of 4-octoxy-4′-cyanobiphenyl were evaluated with HPLC. The decomposed liquid products were characterized by GC-MS. Under optimized conditions i.e., 0.2 mL H 2 O 2 supply, pH value 6, temperature 275 °C and reaction time 5 min, 97.6% of 4-octoxy-4′-cyanobiphenyl was decomposed into simple and environment-friendly products. Based on the mechanism analysis and products characterization, a possible hydrothermal decomposition pathway was proposed. The results indicate that hydrothermal technology is a promising choice for liquid crystal treatment

HIGH-PRESSURE VAPOR-LIQUID EQUILIBRIUM DATA FOR BINARY AND TERNARY SYSTEMS FORMED BY SUPERCRITICAL CO2, LIMONENE AND LINALOOL

Directory of Open Access Journals (Sweden)

MELO S. A. B. VIEIRA DE

1999-01-01

Full Text Available The feasibility of deterpenating orange peel oil with supercritical CO2 depends on relevant vapor-liquid equilibrium data because the selectivity of this solvent for limonene and linalool (the two key components of the oil is of crucial importance. The vapor-liquid equilibrium data of the CO2-limonene binary system was measured at 50, 60 and 70oC and pressures up to 10 MPa, and of the CO2-linalool binary system at 50oC and pressures up to 85 bar. These results were compared with published data when available in the literature. The unpublished ternary phase equilibrium of CO2-limonene-linalool was studied at 50oC and up to 9 MPa. Selectivities obtained using these ternary data were compared with those calculated using binary data and indicate that a selective separation of limonene and linalool can be achieved.

Magnetic, electrical and optical properties of liquid crystals

International Nuclear Information System (INIS)

Florea, S.C.

1980-01-01

This thesis lays stress on the study of thermotrop nematic liquid crystals. But the crystals whose mesomorphism is achieved by an increase and decrease in temperature and the crystal category exhibiting a mesomorphism in a deep freezing phase are also studied. The results of the research carried out in the laboratory of ''active media, lasers and matter-radiation interactions'' of the Institute for Physics and Technology of Radiation Apparata as well as in the laboratories of liquid crystals and nuclear magnetic resonance of the Polytechnical Institute of Bucharest during seven years have had in view two main objectives: to elucidate and prove experimentally a new mechanism of nuclear relaxation in liquid crystals, proposed by the author; to use the current experimental techniques and methods applied in the above-mentioned laboratories to characterize and test some foreign mesomorphic media which are synthesized locally, providing a wide range of applications, such as colour television. (author)

Tunable Channel Drop Filter in a Two-Dimensional Photonic Crystal Modulated by a Nematic Liquid Crystal

Directory of Open Access Journals (Sweden)

2006-01-01

Full Text Available Photonic crystals (PCs have many potential applications because of their ability to control light-wave propagation and because PC-based waveguides may be integrated into optical circuits. We propose a novel tunable PC channel drop filter based on nematic liquid crystals and investigate its properties numerically by using the finite-difference time-domain (FDTD method. The refractive indices of liquid crystals can be actively modulated after infiltrating nematic liquid crystals into the microcavity in PC waveguides with square lattices. Then we can control light propagation in a PC waveguide. We analyze the Q -factors and resonance frequencies of a tunable PC channel drop filter by considering various indices modulation of liquid crystals. The novel component can be used as wavelength division multiplexing in photonic integrated circuits.

Synthesis of novel liquid crystal compounds and their blood compatibility as anticoagulative materials

International Nuclear Information System (INIS)

Tu Mei; Cha Zhenhang; Feng Bohua; Zhou Changren

2006-01-01

The objective of this study was to synthesize new types of cholesteric liquid crystal compounds and study the anticoagulative properties of their composite membranes. Three kinds of cholesteric liquid crystal compounds were synthesized and characterized by infrared spectroscopy, differential scanning calorimetry and optical polarizing microscope. The polysiloxane, as a substrate, was blended with three liquid crystal compounds and was then used as membranes. The anticoagulative property of different polysiloxane liquid crystal composite membranes was identified by the blood compatibility tests. Three cholesteryl liquid crystals synthesized in this work contained hydrophilic soft chains and presented iridescent texture owned by cholesteric liquid crystals in the range of their liquid crystal state temperature, but only cholesteryl acryloyl oxytetraethylene glycol carbonate was in the liquid crystal state at body temperature. When liquid crystals were blended with polysiloxane to form polysiloxane/liquid crystal composite membranes, the haemocompatibility of these membranes could be improved to some extent. The blood compatibility of composite membranes whose hydrophilic property was the best was more excellent than that of other composite membranes, fewer platelets adhered and spread, and showed little distortion on the surface of materials

Invited review liquid crystal models of biological materials and silk spinning.

Science.gov (United States)

Rey, Alejandro D; Herrera-Valencia, Edtson E

2012-06-01

A review of thermodynamic, materials science, and rheological liquid crystal models is presented and applied to a wide range of biological liquid crystals, including helicoidal plywoods, biopolymer solutions, and in vivo liquid crystals. The distinguishing characteristics of liquid crystals (self-assembly, packing, defects, functionalities, processability) are discussed in relation to biological materials and the strong correspondence between different synthetic and biological materials is established. Biological polymer processing based on liquid crystalline precursors includes viscoelastic flow to form and shape fibers. Viscoelastic models for nematic and chiral nematics are reviewed and discussed in terms of key parameters that facilitate understanding and quantitative information from optical textures and rheometers. It is shown that viscoelastic modeling the silk spinning process using liquid crystal theories sheds light on textural transitions in the duct of spiders and silk worms as well as on tactoidal drops and interfacial structures. The range and consistency of the predictions demonstrates that the use of mesoscopic liquid crystal models is another tool to develop the science and biomimetic applications of mesogenic biological soft matter. Copyright © 2011 Wiley Periodicals, Inc.

Nanoparticles Doped, Photorefractive Liquid Crystals

National Research Council Canada - National Science Library

Kaczmarek, Malgosia

2005-01-01

...: The main objectives of this exploratory, short project will concern the study of the quality of liquid crystal cells with diluted suspensions of ferroelectric nanoparticles and their photorefractive properties...

Peculiarities of component interaction in {Gd, Er}-V-Sn Ternary systems at 870 K and crystal structure of RV6Sn6 stannides

International Nuclear Information System (INIS)

Romaka, L.; Stadnyk, Yu.; Romaka, V.V.; Demchenko, P.; Stadnyshyn, M.; Konyk, M.

2011-01-01

Highlights: → {Gd, Er}-V-Sn ternary systems at 870 K are characterized by formation of stannides with general compositions RV 6 Sn 6 . → Isostructural RV 6 Sn 6 compounds were also found with Y, Dy, Ho, Tm, and Lu. → The crystal structure of RV 6 Sn 6 compounds was determined by powder diffraction method. → Structural analysis showed that RV 6 Sn 6 compounds (R = Gd, Dy-Tm, Lu) are disordered; YV 6 Sn 6 is characterized by structure ordering. - Abstract: The phase equilibria in the Gd-V-Sn and Er-V-Sn ternary systems were studied at 870 K by means of X-ray and metallographic analyses in the whole concentration range. Both Gd-V-Sn and Er-V-Sn systems are characterized by formation of one ternary compound at investigated temperature, with stoichiometry RV 6 Sn 6 (SmMn 6 Sn 6 -type, space group P6/mmm, a = 0.55322(3) nm, c = 0.91949(7) nm for Gd, a = 0.55191(2) nm, c = 0.91869(8) nm for Er). Solubility of the third component in the binary compounds was not observed. Compounds with the SmMn 6 Sn 6 -type were also found with Dy, Ho, Tm, and Lu, while YV 6 Sn 6 compound crystallizes in HfFe 6 Ge 6 structure type. All investigated compounds are the first ternary stannides with rare earth elements and vanadium.

Induced Magnetic Anisotropy in Liquid Crystals Doped with Resonant Semiconductor Nanoparticles

Directory of Open Access Journals (Sweden)

Vicente Marzal

2016-01-01

Full Text Available Currently, there are many efforts to improve the electrooptical properties of liquid crystals by means of doping them with different types of nanoparticles. In addition, liquid crystals may be used as active media to dynamically control other interesting phenomena, such as light scattering resonances. In this sense, mixtures of resonant nanoparticles hosted in a liquid crystal could be a potential metamaterial with interesting properties. In this work, the artificial magnetism induced in a mixture of semiconductor nanoparticles surrounded by a liquid crystal is analyzed. Effective magnetic permeability of mixtures has been obtained using the Maxwell-Garnett effective medium theory. Furthermore, permeability variations with nanoparticles size and their concentration in the liquid crystal, as well as the magnetic anisotropy, have been studied.

Magnetic, electric and optic properties of liquid crystals

International Nuclear Information System (INIS)

Florea, St.C.

1980-01-01

We study the nematic liquid crystals of thermotrop type. We also studied the crystals whose mesomorphism occured both at temperature increasing and decreasing and during the supercooling phase (monotrope). Investigation results performed by us have had in view the following: clearing up and experimental support of a new mechanism of nuclear relaxation in liquid crystals, proposed by author; usage of experimental techniques and methods for to characterize and test some mesomorph media used in very important applications, such as color TV. (author)

Liquid crystals for organic thin-film transistors

Science.gov (United States)

Iino, Hiroaki; Usui, Takayuki; Hanna, Jun-Ichi

2015-04-01

Crystalline thin films of organic semiconductors are a good candidate for field effect transistor (FET) materials in printed electronics. However, there are currently two main problems, which are associated with inhomogeneity and poor thermal durability of these films. Here we report that liquid crystalline materials exhibiting a highly ordered liquid crystal phase of smectic E (SmE) can solve both these problems. We design a SmE liquid crystalline material, 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10), for FETs and synthesize it. This material provides uniform and molecularly flat polycrystalline thin films reproducibly when SmE precursor thin films are crystallized, and also exhibits high durability of films up to 200 °C. In addition, the mobility of FETs is dramatically enhanced by about one order of magnitude (over 10 cm2 V-1 s-1) after thermal annealing at 120 °C in bottom-gate-bottom-contact FETs. We anticipate the use of SmE liquid crystals in solution-processed FETs may help overcome upcoming difficulties with novel technologies for printed electronics.

NMR studies of liquid crystals and molecules dissolved in liquid crystal solvents

Energy Technology Data Exchange (ETDEWEB)

Drobny, Gary Peter [Univ. of California, Berkeley, CA (United States)

1982-11-01

This thesis describes several studies in which nuclear magnetic resonance (nmr) spectroscopy has been used to probe the structure, orientation and dynamics of liquid crystal mesogens and molecules dissolved in liquid crystalline phases. In addition, a modern high field nmr spectrometer is described which has been used to perform such nmr studies. Chapter 1 introduces the quantum mechanical formalisms used throughout this thesis and briefly reviews the fundamentals of nuclear spin physics and pulsed nmr spectroscopy. First the density operator is described and a specific form for the canonical ensemble is derived. Then Clebsch-Gordon coefficients, Wigner rotation matrices, and irreducible tensor operators are reviewed. An expression for the equilibrium (Curie) magnetization is obtained and the linear response of a spin system to a strong pulsed r.f. irradiation is described. Finally, the spin interaction Hamiltonians relevant to this work are reviewed together with their truncated forms. Chapter 2 is a deuterium magnetic resonance study of two 'nom' liquid crystals which possess several low temperature mesomorphic phases. Specifically, deuterium quadrupolar echo spectroscopy is used to determine the orientation of the liquid crystal molecules in smectic phases, the changes in molecular orientation and motion that occur at smectic-smectic phase transitions, and the order of the phase transitions. For both compounds, the phase sequence is determined to be isotropic, nematic, smectic A, smectic C, smectic B_A, smectic B_C, and crystalline. The structure of the smectic A phase is found to be consistent with the well-known model of a two dimensional liquid in which molecules are rapidly rotating about their long axes and oriented at right angles to the plane of the layers. Molecules in the smectic C phase are found to have their long axes tilted with respect to the layer normal, and the tilt angle is temperature dependent, increasing from

Crystal Growth and Characterization of MT2Si2 Ternary Intermetallics (M = U, RE and T = 3d, 4d, 5d Transition Metals)

NARCIS (Netherlands)

Menovsky, A.A.; Moleman, A.C.; Snel, G.E.; Gortenmulder, T.J.; Palstra, T.T.M.

1986-01-01

Bulk single crystals of the ternary intermetallic compounds UT2Si2 (T = Ni, Pd, Pt and Ru), LaT2Si2 (T = Pd and Rh) and LuPd2Si2 have been grown from the melt with a modified “tri-arc” Czochralski method. The as-grown crystals were characterized by X-ray, microprobe and chemical analyses. The

Inverse Opal Photonic Crystals as an Optofluidic Platform for Fast Analysis of Hydrocarbon Mixtures.

Science.gov (United States)

Xu, Qiwei; Mahpeykar, Seyed Milad; Burgess, Ian B; Wang, Xihua

2018-06-13

Most of the reported optofluidic devices analyze liquid by measuring its refractive index. Recently, the wettability of liquid on various substrates has also been used as a key sensing parameter in optofluidic sensors. However, the above-mentioned techniques face challenges in the analysis of the relative concentration of components in an alkane hydrocarbon mixture, as both refractive indices and wettabilities of alkane hydrocarbons are very close. Here, we propose to apply volatility of liquid as the key sensing parameter, correlate it to the optical property of liquid inside inverse opal photonic crystals, and construct powerful optofluidic sensors for alkane hydrocarbon identification and analysis. We have demonstrated that via evaporation of hydrocarbons inside the periodic structure of inverse opal photonic crystals and observation of their reflection spectra, an inverse opal film could be used as a fast-response optofluidic sensor to accurately differentiate pure hydrocarbon liquids and relative concentrations of their binary and ternary mixtures in tens of seconds. In these 3D photonic crystals, pure chemicals with different volatilities would have different evaporation rates and can be easily identified via the total drying time. For multicomponent mixtures, the same strategy is applied to determine the relative concentration of each component simply by measuring drying time under different temperatures. Using this optofluidic sensing platform, we have determined the relative concentrations of ternary hydrocarbon mixtures with the difference of only one carbon between alkane hydrocarbons, which is a big step toward detailed hydrocarbon analysis for practical use.

Fusibility diagram of ternary system with incongruently melting double compound

International Nuclear Information System (INIS)

Lutsyk, V.I.; Vorob'eva, V.P.; Sumkina, O.G.

1989-01-01

Temperature calculation and properties of ternary eutectics and concentration coordinates of ternary peritectics accoriding to the linear model of initial crystallization surfaces as an element of the expert system for simulating fusibility diagrams of ternary systems is considered. It is shown that the calculated and experimental data on coordinates of ternary nonvariant points in the systems NaCl-PbCl 2 -CdCl 2 , PbCl 2 -CaCl 2 -UCl 4 , CaF 2 -NaF-CsF and UCl 3 -CaCl 2 -ThCl 4 are in good agreement

Relationships between the morphology and thermoresponsive behavior in micro/nanostructured thermosetting matrixes containing a 4'-(hexyloxy)-4-biphenylcarbonitrile liquid crystal.

Science.gov (United States)

Tercjak, Agnieszka; Mondragon, Iñaki

2008-10-07

Meso/nanostructured thermoresponsive thermosetting materials based on an epoxy resin modified with two different molecular weight amphiphilic poly(styrene- block-ethylene oxide) block copolymers (PSEO) and a low molecular weight liquid crystal, 4'-(hexyloxy)-4-biphenylcarbonitrile (HOBC), were investigated. A strong influence of the addition of PSEO on the morphology generated in HOBC--(diglicydyl ether of bisphenol A epoxy resin/ m-xylylenediamine) was detected, especially in the case of the addition of PSEO block copolymers with a higher PEO-block content and a lower molecular weight. The morphologies generated in the ternary systems also influenced the thermoresponsive behavior of the HOBC separated phase provoked by applying an external field, such as a temperature gradient and an electrical field. Thermal analysis of the investigated materials allowed for a better understanding of the relationships between generated morphology/thermo-optical properties/PSEO:HOBC ratio, and HOBC content. Controlling the relationship between the morphology and thermoresponsive behavior in micro/nanostructured thermosetting materials based on a 4'-(hexyloxy)-4-biphenylcarbonitrile liquid crystal allows the development of materials which can find application in thermo- and in some cases electroresponsive devices, with a high contrast ratio between transparent and opaque states.

Influence of rubbing-alignment on microwave modulation induced by liquid crystal

Directory of Open Access Journals (Sweden)

Wenjiang Ye

2015-06-01

Full Text Available The microwave modulation induced by liquid crystal is decided by the liquid crystal director distribution under an external applied voltage. The rubbing-alignment of substrate has an effect on the liquid crystal director, which must result in the change of microwave phase-shift. To illustrate the influence of rubbing-alignment on the microwave phase-shift, the microwave modulation property of twisted nematic liquid crystal is researched adopting the elastic theory of liquid crystal and the finite-difference iterative method. The variations of microwave phase-shift per unit-length for different pre-tilt and pre-twist angles of liquid crystal on the substrate surface and anchoring energy strengths with the applied voltage are numerically simulated. The result indicates that with the increase of pre-tilt angle and with the decrease of anchoring energy strength the weak anchoring twisted cell with pre-twisted angle 90° relative to the strong anchoring non-twisted cell can increase the microwave phase-shift per unit-length. As a result, for achieving the maximum microwave modulation, the weak anchoring twisted cell with pre-tilt angle 5° and anchoring energy strength 1×10−5J/m2 should be selected, which provides a reliably theoretical foundation for the design of liquid crystal microwave modulator.

Characterising laser beams with liquid crystal displays

Science.gov (United States)

Dudley, Angela; Naidoo, Darryl; Forbes, Andrew

2016-02-01

We show how one can determine the various properties of light, from the modal content of laser beams to decoding the information stored in optical fields carrying orbital angular momentum, by performing a modal decomposition. Although the modal decomposition of light has been known for a long time, applied mostly to pattern recognition, we illustrate how this technique can be implemented with the use of liquid-crystal displays. We show experimentally how liquid crystal displays can be used to infer the intensity, phase, wavefront, Poynting vector, and orbital angular momentum density of unknown optical fields. This measurement technique makes use of a single spatial light modulator (liquid crystal display), a Fourier transforming lens and detector (CCD or photo-diode). Such a diagnostic tool is extremely relevant to the real-time analysis of solid-state and fibre laser systems as well as mode division multiplexing as an emerging technology in optical communication.

Polarization-independent nematic liquid crystal waveguides for optofluidic applications

NARCIS (Netherlands)

d'Alessandro, A.; Martini, L.; Gilardi, G.; Beccherelli, R.; Asquini, R.

2015-01-01

We present the fabrication and the characterization of waveguides made of a nematic liquid crystal infiltrated in poly(dimethylsiloxane) channels. They are made by means of cast and molding technique and patterned using soft photolithography. The orientation of the nematic liquid crystal molecules

Equilibrium study for ternary mixtures of biodiesel

Science.gov (United States)

Doungsri, S.; Sookkumnerd, T.; Wongkoblap, A.; Nuchitprasittichai, A.

2017-11-01

The liquid-liquid equilibrium (LLE) data for the ternary mixtures of methanol + fatty acid methyl ester (FAME) + palm oil and FAME + palm oil + glycerol at various temperatures from 35 to 55°C, the tie lines and binodial curves were also investigated and plotted in the equilibrium curve. The experimental results showed that the binodial curves of methanol + FAME + palm oil depended significantly with temperature while the binodial curves of FAME + palm oil + glycerol illustrated insignificant change with temperatures. The interaction parameters between liquid pair obtained for NRTL (Nonrandom Two-Liquid) and UNIQUAC (Universal Quasi-Chemical Theory) models from the experimental data were also investigated. It was found that the correlated parameters of UNIQUAC model for system of FAME + palm oil + glycerol, denoted as a13 and a31, were 580.42K and -123.69K, respectively, while those for system of methanol + FAME + palm oil, denoted as a42 and a24, were 71.48 K and 965.57K, respectively. The ternary LLE data reported here would be beneficial for engineers and scientists to use for prediction of yield and purity of biodiesel for the production. The UNIQUAC model agreed well with the experimental data of ternary mixtures of biodiesel.

Isobaric (vapor + liquid) equilibria for the ternary system of (ethanol + water + 1,3-propanediol) and three constituent binary systems at P = 101.3 kPa

International Nuclear Information System (INIS)

Lai, Hung-Sheng; Lin, Yi-Feng; Tu, Chein-Hsiun

2014-01-01

Highlights: • We report VLE data at 101.3 kPa for mixtures of ethanol, water, and 1,3-propanediol. • The VLE data were correlated by the Wilson, NRTL, and UNIQUAC models. • The ternary VLE data were predicted from binary VLE data using the three models. • The VLE effect of 1,3-propanediol on the azeotropic ethanol + water mixture was studied. • The azeotropic point of ethanol + water disappears at 30 wt% of 1,3-propanediol. -- Abstract: Isobaric (vapor + liquid) equilibrium (VLE) at P = 101.3 kPa have been measured for the ternary system of (ethanol + water + 1,3-propanediol) and for the corresponding binary systems of (ethanol + water), (ethanol + 1,3-propanediol), and (water + 1,3-propnaediol) using a Hunsmann-type equilibrium still with circulation of both vapor and liquid phases. The ternary mixtures were prepared by mixing ethanol and pure water with three concentrations (10, 30, and 50) wt% of 1,3-propanediol in the overall liquid mixtures in order to study the effect of 1,3-propanediol on the VLE of (ethanol + water). The equilibrium compositions of mixtures were analyzed by gas–liquid chromatography. The relative volatilities of ethanol with respect to water were also determined. The results of the investigation indicate the disappearance of the binary azeotrope between ethanol and water when the concentration of 1,3-propanediol is up to 30 wt%. The liquid activity coefficients were calculated using the modified Raoult’s law. The thermodynamic consistency of the VLE data was performed for the three binary systems using Van Ness direct test. The new binary and ternary VLE data were successfully correlated using the Wilson, NRTL, and UNIQUAC models, for which the binary interaction parameters are reported

Cohesion energy calculations for ternary ionic novel crystals

International Nuclear Information System (INIS)

Vazquez P, G.; Cabrera, E.; Mijangos, R.R.; Valdez, E.; Duarte, C.

2001-01-01

The present work calculates the value of the link energy of a crystalline ternary structure newly formed by alkali halides. The ternary structure prepared with different concentrations of KCl x KBrRbCl 2 maintains a very good miscibility and stability. The calculation is based on the use of a generalization of the Vegard law (which generally is valid for binary compounds) for calculating the values of the lattice constant and the repulsive m exponent. The value of the lattice parameter given by X-ray diffractometry agrees with the close approximation of the calculated value of the method used. It also compares the value of energy cohesion obtained by the Born expression with more complex approximations. (Author)

A helical naphthopyran dopant for photoresponsive cholesteric liquid crystals

OpenAIRE

Kim, Yuna; Frigoli, Michel; Vanthuyne, Nicolas; Tamaoki, Nobuyuki

2017-01-01

The first photoresponsive cholesteric liquid crystal comprising a photoisomerizable helical naphthopyran derivative dopant and a nematic liquid crystal is reported. An unprecedented helical twisting power switching ratio of over 90% allowed us to demonstrate multi-cycle rotational motion of micro-objects by UV light irradiation.

Effects of thermo-order-mechanical coupling on band structures in liquid crystal nematic elastomer porous phononic crystals.

Science.gov (United States)

Yang, Shuai; Liu, Ying

2018-08-01

Liquid crystal nematic elastomers are one kind of smart anisotropic and viscoelastic solids simultaneously combing the properties of rubber and liquid crystals, which is thermal sensitivity. In this paper, the wave dispersion in a liquid crystal nematic elastomer porous phononic crystal subjected to an external thermal stimulus is theoretically investigated. Firstly, an energy function is proposed to determine thermo-induced deformation in NE periodic structures. Based on this function, thermo-induced band variation in liquid crystal nematic elastomer porous phononic crystals is investigated in detail. The results show that when liquid crystal elastomer changes from nematic state to isotropic state due to the variation of the temperature, the absolute band gaps at different bands are opened or closed. There exists a threshold temperature above which the absolute band gaps are opened or closed. Larger porosity benefits the opening of the absolute band gaps. The deviation of director from the structural symmetry axis is advantageous for the absolute band gap opening in nematic state whist constrains the absolute band gap opening in isotropic state. The combination effect of temperature and director orientation provides an added degree of freedom in the intelligent tuning of the absolute band gaps in phononic crystals. Copyright © 2018 Elsevier B.V. All rights reserved.

Thermo-, photo-, and mechano-responsive liquid crystal networks enable tunable photonic crystals.

Science.gov (United States)

Akamatsu, N; Hisano, K; Tatsumi, R; Aizawa, M; Barrett, C J; Shishido, A

2017-10-25

Tunable photonic crystals exhibiting optical properties that respond reversibly to external stimuli have been developed using liquid crystal networks (LCNs) and liquid crystal elastomers (LCEs). These tunable photonic crystals possess an inverse opal structure and are photo-responsive, but circumvent the usual requirement to contain dye molecules in the structure that often limit their applicability and cause optical degradation. Herein, we report tunable photonic crystal films that reversibly tune the reflection peak wavelength under thermo-, photo- and mechano-stimuli, through bilayering a stimuli-responsive LCN including azobenzene units with a colourless inverse opal film composed of non-responsive, flexible durable polymers. By mechanically deforming the azobenzene containing LCN via various stimuli, the reflection peak wavelength from the bilayered film assembly could be shifted on demand. We confirm that the reflection peak shift occurs due to the deformation of the stimuli-responsive layer propagating towards and into the inverse opal layer to change its shape in response, and this shift behaviour is repeatable without optical degradation.

(Liquid + liquid) equilibrium data for the ternary systems (cycloalkane + ethylbenzene + 1-ethyl-3-methylimidazolim ethylsulfate) at T = 298.15 K and atmospheric pressure

International Nuclear Information System (INIS)

Gonzalez, Emilio J.; Calvar, Noelia; Dominguez, Irene; Dominguez, Angeles

2011-01-01

Research highlights: → [EMim][ESO 4 ] was studied as solvent to extract ethylbenzene from cycloalkanes. → (Liquid + liquid) equilibrium data were measured at 298.15K and atmospheric pressure. → Selectivity and solute distribution ratio were obtained and compared with literature. → Experimental data were satisfactorily correlated using NRTL and UNIQUAC models. → [EMim][ESO 4 ] can be used as solvent for the studied (liquid + liquid) extraction. - Abstract: In this paper, (liquid + liquid) equilibrium (LLE) data for the ternary systems (cyclohexane, or cyclooctane, or methylcyclohexane + ethylbenzene + 1-ethyl-3-methylimidazolium ethylsulfate) have been determined experimentally at T = 298.15 K and atmospheric pressure. The solubility curves and the tie-line compositions of the conjugate phases were obtained by means of density. The degree of consistency of the tie-lines was tested using the Othmer-Tobias equation, and the Non-Random Two-Liquid (NRTL) and the Universal Quasi-Chemical (UNIQUAC) models were used to correlate the phase equilibrium in the systems. Selectivity and solute distribution ratio were evaluated for the immiscible region.

Molecular dynamics of liquid crystals

Science.gov (United States)

Sarman, Sten

1997-02-01

We derive Green-Kubo relations for the viscosities of a nematic liquid crystal. The derivation is based on the application of a Gaussian constraint algorithm that makes the director angular velocity of a liquid crystal a constant of motion. Setting this velocity equal to zero means that a director-based coordinate system becomes an inertial frame and that the constraint torques do not do any work on the system. The system consequently remains in equilibrium. However, one generates a different equilibrium ensemble. The great advantage of this ensemble is that the Green-Kubo relations for the viscosities become linear combinations of time correlation function integrals, whereas they are complicated rational functions in the conventional canonical ensemble. This facilitates the numerical evaluation of the viscosities by molecular dynamics simulations.

Nanoparticle guests in lyotropic liquid crystals

Science.gov (United States)

Dölle, Sarah; Park, Ji Hyun; Schymura, Stefan; Jo, Hyeran; Scalia, Giusy; Lagerwall, Jan P. F.

In this chapter we discuss the benefits, peculiarities and main challenges related to nanoparticle templating in lyotropic liquid crystals. We first give a brief bird's-eye view of the field, discussing different nanoparticles as well as different lyotropic hosts that have been explored, but then quickly focus on the dispersion of carbon nanotubes in surfactant-based lyotropic nematic phases. We discuss in some detail how the transfer of orientational order from liquid crystal host to nanoparticle guest can be verified and which degree of ordering can be expected, as well as the importance of choosing the right surfactant and its concentration for the stability of the nanoparticle suspension. We introduce a method for dispersing nanoparticles with an absolute minimum of stabilizing surfactant, based on dispersion below the Krafft temperature, and we discuss the peculiar phenomenon of filament formation in lyotropic nematic phases with a sufficient concentration of well-dispersed carbon nanotubes. Finally, we describe how the total surfactant concentration in micellar nematics can be greatly reduced by combining cat- and anionic surfactants, and we discuss how nanotubes can help in inducing the liquid crystal phase close to the isotropic-nematic boundary.

(Liquid + liquid) equilibria measurements for ternary systems (sulfolane + a carboxylic acid + n-heptane) at T = 303.15 K and at 0.1 MPa

International Nuclear Information System (INIS)

Cele, N.P.; Bahadur, I.; Redhi, G.G.; Ebenso, E.E.

2016-01-01

Highlights: • The (liquid + liquid) equilibrium for (sulfolane + a carboxylic acid + heptane) was measured. • Selectivity values for solvent separation efficiency were calculated. • Separation of carboxylic acids from heptane is feasible by extraction. • Three parameter equations have been fitted to the binodal curve data. • The NRTL and UNIQUAC models were used to correlate the experimental data. - Abstract: In the present work, new (liquid + liquid) equilibrium (LLE) values are reported for ternary systems {sulfolane(1) + acetic acid, or propanoic acid, or butanoic acid, or 2-methylpropanoic acid, or pentanoic acid, or 3-methylbutanoic acid (2) + n-heptane (3)} at T = 303.15 K and at p = 0.1 MPa. The mutual solubility of carboxylic acid in sulfolane is dependent on the length and structure of the alkyl chain of the carboxylic acid; it progressively increases with an increase in the alkyl chain of the carboxylic acid. The single phase homogenous region increases as the alkyl chain of the carboxylic acid increases. The n-heptane is most soluble in the carboxylic acid mixtures with long alkyl chain, that is, (3-methylbutanoic acid + sulfolane) and (pentanoic acid + sulfolane) systems and least soluble in the carboxylic acid with short alkyl chain (acetic acid + sulfolane) system. Carboxylic acid together with many other oxygenates and hydrocarbons are produced by SASOL Company in South Africa using the Fischer–Tropsch process. The details about this process are given in introduction section. The NRTL and UNIQUAC models were used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. It was found that the NRTL model fits the experimental values significantly better than the UNIQUAC model.

High Resolution Displays Using NCAP Liquid Crystals

Science.gov (United States)

Macknick, A. Brian; Jones, Phil; White, Larry

1989-07-01

Nematic curvilinear aligned phase (NCAP) liquid crystals have been found useful for high information content video displays. NCAP materials are liquid crystals which have been encapsulated in a polymer matrix and which have a light transmission which is variable with applied electric fields. Because NCAP materials do not require polarizers, their on-state transmission is substantially better than twisted nematic cells. All dimensional tolerances are locked in during the encapsulation process and hence there are no critical sealing or spacing issues. By controlling the polymer/liquid crystal morphology, switching speeds of NCAP materials have been significantly improved over twisted nematic systems. Recent work has combined active matrix addressing with NCAP materials. Active matrices, such as thin film transistors, have given displays of high resolution. The paper will discuss the advantages of NCAP materials specifically designed for operation at video rates on transistor arrays; applications for both backlit and projection displays will be discussed.

Electrically tunable zero dispersion wavelengths in photonic crystal fibers filled with a dual frequency addressable liquid crystal

International Nuclear Information System (INIS)

Wahle, Markus; Kitzerow, Heinz-Siegfried

2015-01-01

We present a liquid crystal (LC) infiltrated photonic crystal fiber, which enables the electrical tuning of the position of zero dispersion wavelengths (ZDWs). A dual frequency addressable liquid crystal is aligned perpendicular on the inclusion walls of a photonic crystal fiber, which results in an escaped radial director field. The orientation of the LC is controlled by applying an external electric field. Due to the high index of the liquid crystal the fiber guides light by the photonic band gap effect. Multiple ZDWs exist in the visible and near infrared. The positions of the ZDWs can be either blue or red shifted depending on the frequency of the applied voltage

Recent Advances in Discotic Liquid Crystal-Assisted Nanoparticles

Directory of Open Access Journals (Sweden)

Ashwathanarayana Gowda

2018-03-01

Full Text Available This article primarily summarizes recent advancement in the field of discotic liquid crystal (DLC nanocomposites. Discotic liquid crystals are nanostructured materials, usually 2 to 6 nm size and have been recognized as organic semiconducting materials. Recently, it has been observed that the dispersion of small concentration of various functionalized zero-, one- and two-dimensional nanomaterials in the supramolecular order of mesophases of DLCs imparts negligible impact on liquid crystalline properties but enhances their thermal, supramolecular and electronic properties. Synthesis, characterization and dispersion of various nanoparticles in different discotics are presented.

Transmission properties of one-dimensional ternary plasma photonic crystals

International Nuclear Information System (INIS)

Shiveshwari, Laxmi; Awasthi, S. K.

2015-01-01

Omnidirectional photonic band gaps (PBGs) are found in one-dimensional ternary plasma photonic crystals (PPC) composed of single negative metamaterials. The band characteristics and transmission properties are investigated through the transfer matrix method. We show that the proposed structure can trap light in three-dimensional space due to the elimination of Brewster's angle transmission resonance allowing the existence of complete PBG. The results are discussed in terms of incident angle, layer thickness, dielectric constant of the dielectric material, and number of unit cells (N) for TE and TM polarizations. It is seen that PBG characteristics is apparent even in an N ≥ 2 system, which is weakly sensitive to the incident angle and completely insensitive to the polarization. Finite PPC could be used for multichannel transmission filter without introducing any defect in the geometry. We show that the locations of the multichannel transmission peaks are in the allowed band of the infinite structure. The structure can work as a single or multichannel filter by varying the number of unit cells. Binary PPC can also work as a polarization sensitive tunable filter

Transmission properties of one-dimensional ternary plasma photonic crystals

Energy Technology Data Exchange (ETDEWEB)

Shiveshwari, Laxmi [Department of Physics, K. B. Womens' s College, Hazaribagh 825 301 (India); Awasthi, S. K. [Department of Physics and Material Science and Engineering, Jaypee Institute of Information Technology, Noida 201 304 (India)

2015-09-15

Omnidirectional photonic band gaps (PBGs) are found in one-dimensional ternary plasma photonic crystals (PPC) composed of single negative metamaterials. The band characteristics and transmission properties are investigated through the transfer matrix method. We show that the proposed structure can trap light in three-dimensional space due to the elimination of Brewster's angle transmission resonance allowing the existence of complete PBG. The results are discussed in terms of incident angle, layer thickness, dielectric constant of the dielectric material, and number of unit cells (N) for TE and TM polarizations. It is seen that PBG characteristics is apparent even in an N ≥ 2 system, which is weakly sensitive to the incident angle and completely insensitive to the polarization. Finite PPC could be used for multichannel transmission filter without introducing any defect in the geometry. We show that the locations of the multichannel transmission peaks are in the allowed band of the infinite structure. The structure can work as a single or multichannel filter by varying the number of unit cells. Binary PPC can also work as a polarization sensitive tunable filter.

Liquid crystal alignment in electro-responsive nanostructured thermosetting materials based on block copolymer dispersed liquid crystal

Energy Technology Data Exchange (ETDEWEB)

Tercjak, A; Garcia, I; Mondragon, I [Materials-Technologies Group, Departamento IngenierIa Quimica y M Ambiente, Escuela Politecnica, Universidad PaIs Vasco/Euskal Herriko Unibertsitatea, Plaza Europa 1, E-20018 Donostia-San Sebastian (Spain)], E-mail: scptesza@sc.ehu.es, E-mail: inaki.mondragon@ehu.es

2008-07-09

Novel well-defined nanostructured thermosetting systems were prepared by modification of a diglicydylether of bisphenol-A epoxy resin (DGEBA) with 10 or 15 wt% amphiphilic poly(styrene-b-ethylene oxide) block copolymer (PSEO) and 30 or 40 wt% low molecular weight liquid crystal 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) using m-xylylenediamine (MXDA) as a curing agent. The competition between well-defined nanostructured materials and the ability for alignment of the liquid crystal phase in the materials obtained has been studied by atomic and electrostatic force microscopy, AFM and EFM, respectively. Based on our knowledge, this is the first time that addition of an adequate amount (10 wt%) of a block copolymer to 40 wt% HBC-(DGEBA/MXDA) leads to a well-organized nanostructured thermosetting system (between a hexagonal and worm-like ordered structure), which is also electro-responsive with high rate contrast. This behavior was confirmed using electrostatic force microscopy (EFM), by means of the response of the HBC liquid crystal phase to the voltage applied to the EFM tip. In contrast, though materials containing 15 wt% PSEO and 30 wt% HBC also form a well-defined nanostructured thermosetting system, they do not show such a high contrast between the uncharged and charged surface.

Liquid crystal alignment in electro-responsive nanostructured thermosetting materials based on block copolymer dispersed liquid crystal.

Science.gov (United States)

Tercjak, A; Garcia, I; Mondragon, I

2008-07-09

Novel well-defined nanostructured thermosetting systems were prepared by modification of a diglicydylether of bisphenol-A epoxy resin (DGEBA) with 10 or 15 wt% amphiphilic poly(styrene-b-ethylene oxide) block copolymer (PSEO) and 30 or 40 wt% low molecular weight liquid crystal 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) using m-xylylenediamine (MXDA) as a curing agent. The competition between well-defined nanostructured materials and the ability for alignment of the liquid crystal phase in the materials obtained has been studied by atomic and electrostatic force microscopy, AFM and EFM, respectively. Based on our knowledge, this is the first time that addition of an adequate amount (10 wt%) of a block copolymer to 40 wt% HBC-(DGEBA/MXDA) leads to a well-organized nanostructured thermosetting system (between a hexagonal and worm-like ordered structure), which is also electro-responsive with high rate contrast. This behavior was confirmed using electrostatic force microscopy (EFM), by means of the response of the HBC liquid crystal phase to the voltage applied to the EFM tip. In contrast, though materials containing 15 wt% PSEO and 30 wt% HBC also form a well-defined nanostructured thermosetting system, they do not show such a high contrast between the uncharged and charged surface.

Liquid crystal alignment in electro-responsive nanostructured thermosetting materials based on block copolymer dispersed liquid crystal

International Nuclear Information System (INIS)

Tercjak, A; Garcia, I; Mondragon, I

2008-01-01

Novel well-defined nanostructured thermosetting systems were prepared by modification of a diglicydylether of bisphenol-A epoxy resin (DGEBA) with 10 or 15 wt% amphiphilic poly(styrene-b-ethylene oxide) block copolymer (PSEO) and 30 or 40 wt% low molecular weight liquid crystal 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) using m-xylylenediamine (MXDA) as a curing agent. The competition between well-defined nanostructured materials and the ability for alignment of the liquid crystal phase in the materials obtained has been studied by atomic and electrostatic force microscopy, AFM and EFM, respectively. Based on our knowledge, this is the first time that addition of an adequate amount (10 wt%) of a block copolymer to 40 wt% HBC-(DGEBA/MXDA) leads to a well-organized nanostructured thermosetting system (between a hexagonal and worm-like ordered structure), which is also electro-responsive with high rate contrast. This behavior was confirmed using electrostatic force microscopy (EFM), by means of the response of the HBC liquid crystal phase to the voltage applied to the EFM tip. In contrast, though materials containing 15 wt% PSEO and 30 wt% HBC also form a well-defined nanostructured thermosetting system, they do not show such a high contrast between the uncharged and charged surface

Investigation of the liquid crystal alignment layer: effect on electrical properties

International Nuclear Information System (INIS)

Abderrahmen, Asma; Romdhane, Fayda Fekih; Gharbi, Abdelhafidh; Ouada, Hafedh Ben

2008-01-01

We investigate the electrical behavior of a symmetric liquid crystal (LC) cell: elecrode-silane-LC-silane-electrode. The silane (chlorodimethyloctadecyl-silane) layer induces a homeotropic orientation of the nematic liquid crystal (NLC) molecules. The wettability technique is used to detect the change of the surface energy of the electrode upon cleaning and silane layer deposition. We report on the dynamic impedance measurements of the nematic liquid crystal cell. It is found that the silane alignment layer has a blocking effect on the liquid crystal (LC) cell. We also study the relaxation behavior of the cell which is later assimilated as an electrical equivalent circuit

Investigation of the liquid crystal alignment layer: effect on electrical properties

Energy Technology Data Exchange (ETDEWEB)

Abderrahmen, Asma; Romdhane, Fayda Fekih; Gharbi, Abdelhafidh [Laboratoire de la matiere molle, Faculte des sciences, Tunis (Tunisia); Ouada, Hafedh Ben [Laboratoire de physique et chimie des interfaces, Faculte des sciences, 5000 Monastir (Tunisia)], E-mail: asma_abderrahmen@yahoo.fr

2008-04-01

We investigate the electrical behavior of a symmetric liquid crystal (LC) cell: elecrode-silane-LC-silane-electrode. The silane (chlorodimethyloctadecyl-silane) layer induces a homeotropic orientation of the nematic liquid crystal (NLC) molecules. The wettability technique is used to detect the change of the surface energy of the electrode upon cleaning and silane layer deposition. We report on the dynamic impedance measurements of the nematic liquid crystal cell. It is found that the silane alignment layer has a blocking effect on the liquid crystal (LC) cell. We also study the relaxation behavior of the cell which is later assimilated as an electrical equivalent circuit.

Slow-light enhanced optical detection in liquid-infiltrated photonic crystals

DEFF Research Database (Denmark)

Pedersen, Martin Erland Vestergaard; Rishøj, Lars Søgaard; Steffensen, Henrik

2007-01-01

Slow-light enhanced optical detection in liquid-infiltrated photonic crystals is theoretically studied. Using a scattering-matrix approach and the Wigner–Smith delay time concept, we show that optical absorbance benefits both from slow-light phenomena as well as a high filling factor of the energy...... residing in the liquid. Utilizing strongly dispersive photonic crystal structures, we numerically demonstrate how liquid-infiltrated photonic crystals facilitate enhanced light–matter interactions, by potentially up to an order of magnitude. The proposed concept provides strong opportunities for improving...

Molecular dynamics study of the ternary Cu50Ti25Zr25 bulk glass forming alloy

Directory of Open Access Journals (Sweden)

Celtek M.

2011-05-01

Full Text Available The structure and thermodynamic properties of a ternary Cu50Ti25Zr25 metallic glass forming alloy in solid-liquid to glass phases were studied using molecular dynamics (MD method based on tight-binding (TB potentials. An atomic description of the melting, glass formation and crystallization process has been analyzed using different heating and cooling rates. The computed Glass Forming Ability (GFA parameters are in good agreement with experimental data. The structure analysis of the Cu50Ti25Zr25 based on molecular dynamics simulation will be also presented and compared with available MD results. We have also discussed the crystallization transition with two different interatomic potentials used in this work

Characterization of liquid products from the co-cracking of ternary and quaternary mixture of petroleum vacuum residue, polypropylene, Samla coal and Calotropis Procera

Energy Technology Data Exchange (ETDEWEB)

M. Ahmaruzzaman; D.K. Sharma [Indian Institute of Technology Delhi, New Delhi (India). Centre for Energy Studies

2008-08-15

The co-cracking of the petroleum vacuum residue (XVR) with polypropylene (PP), Samla coal (SC) and Calotropis procera (CL) has been carried out in a batch reactor under isothermal conditions at atmospheric pressure. The liquids obtained by co-cracking have been characterized by Fourier transform infrared spectroscopy, high performance liquid chromatography, {sup 1}H nuclear magnetic resonance (NMR), {sup 13}C NMR, gel permeation chromatography (GPC), and inductively coupled argon plasma analyses. It was found that the liquid products obtained from the co-cracking of ternary and quaternary mixtures of the petroleum vacuum residue with polypropylene, coal and C. procera contained less than 1 ppm of Ni and V. The HPLC analyses indicates that the liquids obtained from the cracking of ternary mixture of XVR+PP+CL were mainly aliphatic in nature (saturates content 87.4%). NMR analyses showed that the aromatic carbon contents decreased (15.0%) in the liquid products derived from the co-cracking of quaternary mixtures of XVR+PP+SC+CL compared to their theoretical averages (taking the averages of aromatic carbon contents of the liquids from XVR, PP, SC and CL individually). The overall results indicated that there exists a definite interaction of reactive species when XVR, PP, SC and CL were co-cracked together. 27 refs., 5 tabs.

Effect of Ni-Co Ternary Molten Salt Catalysts on Coal Catalytic Pyrolysis Process

Science.gov (United States)

Cui, Xin; Qi, Cong; Li, Liang; Li, Yimin; Li, Song

2017-08-01

In order to facilitate efficient and clean utilization of coal, a series of Ni-Co ternary molten salt crystals are explored and the catalytic pyrolysis mechanism of Datong coal is investigated. The reaction mechanisms of coal are achieved by thermal gravimetric analyzer (TGA), and a reactive kinetic model is constructed. The microcosmic structure and macerals are observed by scanning electron microscope (SEM). The catalytic effects of ternary molten salt crystals at different stages of pyrolysis are analyzed. The experimental results show that Ni-Co ternary molten salt catalysts have the capability to bring down activation energy required by pyrolytic reactions at its initial phase. Also, the catalysts exert a preferable catalytic action on macromolecular structure decomposition and free radical polycondensation reactions. Furthermore, the high-temperature condensation polymerization is driven to decompose further with a faster reaction rate by the additions of Ni-Co ternary molten salt crystal catalysts. According to pyrolysis kinetic research, the addition of catalysts can effectively decrease the activation energy needed in each phase of pyrolysis reaction.

Liquid Crystal Microlenses for Autostereoscopic Displays

Directory of Open Access Journals (Sweden)

José Francisco Algorri

2016-01-01

Full Text Available Three-dimensional vision has acquired great importance in the audiovisual industry in the past ten years. Despite this, the first generation of autostereoscopic displays failed to generate enough consumer excitement. Some reasons are little 3D content and performance issues. For this reason, an exponential increase in three-dimensional vision research has occurred in the last few years. In this review, a study of the historical impact of the most important technologies has been performed. This study is carried out in terms of research manuscripts per year. The results reveal that research on spatial multiplexing technique is increasing considerably and today is the most studied. For this reason, the state of the art of this technique is presented. The use of microlenses seems to be the most successful method to obtain autostereoscopic vision. When they are fabricated with liquid crystal materials, extended capabilities are produced. Among the numerous techniques for manufacturing liquid crystal microlenses, this review covers the most viable designs for its use in autostereoscopic displays. For this reason, some of the most important topologies and their relation with autostereoscopic displays are presented. Finally, the challenges in some recent applications, such as portable devices, and the future of three-dimensional displays based on liquid crystal microlenses are outlined.

Photo-Induced Phase Transitions to Liquid Crystal Phases: Influence of the Chain Length from C8E4 to C14E4

Directory of Open Access Journals (Sweden)

Simone Techert

2009-09-01

Full Text Available Photo-induced phase transitions are characterized by the transformation from phase A to phase B through the absorption of photons. We have investigated the mechanism of the photo-induced phase transitions of four different ternary systems CiE4/alkane (i with n = 8, 10, 12, 14; cyclohexane/H2O. We were interested in understanding the effect of chain length increase on the dynamics of transformation from the microemulsion phase to the liquid crystal phase. Applying light pump (pulse/x-ray probe (pulse techniques, we could demonstrate that entropy and diffusion control are the driving forces for the kind of phase transition investigated.

Optical Study of Liquid Crystal Doped with Multiwalled Carbon Nanotube

Science.gov (United States)

Gharde, Rita A.; Thakare, Sangeeta Y.

2014-11-01

Liquid crystalline materials have been useful for display devices i.e watches, calculators, automobile dashboards, televisions, multi media projectors etc. as well as in electro tunable lasers, optical fibers and lenses. Carbon nanotube is chosen as the main experimental factor in this study as it has been observed that Carbon Nano Tube influence the existing properties of liquid crystal host and with the doping of CNT can enhance1 the properties of LC. The combination of carbon nanotube (CNT) and liquid crystal (LC) materials show considerable interest in the scientific community due to unique physical properties of CNT in liquid crystal. Dispersion of CNTs in LCs can provide us a cheap, simple, versatile and effective means of controlling nanotube orientation on macroscopic scale with no restrictions on nanotube type. LCs have the long range orientational order rendering them to be anisotropic phases. If CNTs can be well dispersed in LC matrix, they will align with their long axes along the LC director to minimize distortions of the LC director field and the free energy. In this paper, we doped liquid crystal (Cholesteryl Nonanoate) by a small amount of multiwall carbon nanotube 0.05% and 0.1% wt. We found that by adding carbon nanotube to liquid crystals the melting point of the mixture is decreased but TNI is increased. It has been also observed that with incereas in concentration of carbon nanotube into liquid crystal shows conciderable effect on LC. The prepared samples were characterized using various techniques to study structural, thermal and optical properties i.e PMS, FPSS, UV-Vis spectroscopy, FT-IR measurements, and DTA.

New developments in flexible cholesteric liquid crystal displays

Science.gov (United States)

Schneider, Tod; Davis, Donald J.; Franklin, Sean; Venkataraman, Nithya; McDaniel, Diaz; Nicholson, Forrest; Montbach, Erica; Khan, Asad; Doane, J. William

2007-02-01

Flexible Cholesteric liquid crystal displays have been rapidly maturing into a strong contender in the flexible display market. Encapsulation of the Cholesteric liquid crystal permits the use of flexible plastic substrates and roll-to-roll production. Recent advances include ultra-thin displays, laser-cut segmented displays of variable geometry, and smart card applications. Exciting technologies such as simultaneous laser-edge sealing and singulation enable high volume production, excellent quality control and non-traditional display geometries and formats.

Multicomponent ternary cocrystals of the sulfonamide group with pyridine-amides and lactams.

Science.gov (United States)

Bolla, Geetha; Nangia, Ashwini

2015-11-04

SMBA was selected as a bifunctional sulfa drug to design ternary cocrystals with pyridine amides and lactam coformers. Supramolecular assembly of five ternary cocrystals of p-sulfonamide benzoic acid with nicotinamide and 2-pyridone is demonstrated and reproducible heterosynthons are identified for crystal engineering.

Bistable switching in dual-frequency liquid crystals

Energy Technology Data Exchange (ETDEWEB)

Palto, S. P., E-mail: palto@online.ru; Barnik, M I [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2006-06-15

Various bistable switching modes in nematic liquid crystals with frequency inversion of the sign of dielectric anisotropy are revealed and investigated. Switching between states with different helicoidal distributions of the director field of a liquid crystal, as well as between uniform and helicoidal states, is realized by dual-frequency waveforms of a driving voltage. A distinctive feature of the dual-frequency switching is that the uniform planar distribution of the director field may correspond to a thermodynamically equilibrium state, and the chirality of an LC is not a necessary condition for switching to a helicoidal state.

Local layer structure of smectic liquid crystals by X-ray micro-diffraction

CERN Document Server

Takanishi, Y

2003-01-01

The local layer structure of smectic liquid crystal has been measured using time-resolved synchrotron X-ray micro-diffraction. Typical layer disorders observed in surface stabilized (anti-) ferroelectric liquid crystals, i.e. a stripe texture, a needed-like defect and a zigzag defect, are directly analyzed. The detailed analysis slows that the surface anchoring force due to the interaction between the liquid crystal molecule and the alignment thin film plays an important role to realize both the static and dynamic local layer structures. The layer structure of the circular domain observed in the liquid crystal of bent-shaped molecules found to depend on the applied electric field though the optical micrograph shows little difference. The frustrated, double and single layer structures of the bent-shaped molecule liquid crystal are determined depending on the terminal alkyl chain length. (author)

Liquid densities and excess molar volumes for (ionic liquids + methanol + water) ternary system at atmospheric pressure and at various temperatures

Energy Technology Data Exchange (ETDEWEB)

Deenadayalu, Nirmala [Department of Chemistry, Durban University of Technology, Steve Biko Campus, P.O. Box 1334, Durban, KwaZulu-Natal 4001 (South Africa)], E-mail: NirmalaD@dut.ac.za; Kumar, Satish; Bhujrajh, Pravena [Department of Chemistry, Durban University of Technology, Steve Biko Campus, P.O. Box 1334, Durban, KwaZulu-Natal 4001 (South Africa)

2007-09-15

Excess molar volumes, V{sub m}{sup E} have been evaluated from density measurements over the entire composition range for ternary liquid system of ionic liquid (1-ethyl-3-methyl-imidazolium diethylenglycol monomethylether sulphate {l_brace}[EMIM][CH{sub 3}(OCH{sub 2}CH{sub 2}){sub 2}OSO{sub 3}]) (1) + methanol (2) + water (3){r_brace} at T = (298.15, 303.15, and 313.15) K. A vibrating tube densimeter was used for these measurements at atmospheric pressure. The V{sub m}{sup E} values were found to be negative at T = (298.15 and 303.15) K. For {l_brace}[EMIM][CH{sub 3}(OCH{sub 2}CH{sub 2}){sub 2}OSO{sub 3}] (1) + methanol (2) + water (3){r_brace} at T = 313.15 K the V{sub m}{sup E} values become positive at higher mole fraction of ionic liquid and at a corresponding decrease in mole fraction of water. All the experimental data were fitted with the Redlich-Kister equation. The results have also been analysed in term of graph theoretical approach.

Passive Temperature Stabilization of Silicon Photonic Devices Using Liquid Crystals

Directory of Open Access Journals (Sweden)

Joanna Ptasinski

2014-03-01

Full Text Available In this work we explore the negative thermo-optic properties of liquid crystal claddings for passive temperature stabilization of silicon photonic integrated circuits. Photonic circuits are playing an increasing role in communications and computing, but they suffer from temperature dependent performance variation. Most existing techniques aimed at compensation of thermal effects rely on power hungry Joule heating. We show that integrating a liquid crystal cladding helps to minimize the effects of a temperature dependent drift. The advantage of liquid crystals lies in their high negative thermo-optic coefficients in addition to low absorption at the infrared wavelengths.

Growth of a New Ternary BON Crystal on Si(100) by Plasma-Assisted MOCVD and Study on the Effects of Fed Gas and Growth Temperature

Science.gov (United States)

Chen, G. C.; Lee, S.-B.; Boo, J.-H.

A new ternary BOxNy crystal was grown on Si(100) substrate at 500°C by low-frequency (100 kHz) radio-frequency (rf) derived plasma-assisted MOCVD with an organoborate precursor. The as-grown deposits were characterized by SEM, TED, XPS, XRD, AFM and FT-IR. The experimental results showed that BOxNy crystal was apt to be formed at N-rich atmosphere and high temperature. The decrease of hydrogen flux in fed gases was of benefit to form BON crystal structure. The crystal structure of BOxNy was as similar to that of H3BO3 in this study.

Effect of temperature on the morphology and electro-optical properties of liquid crystal physical gel

International Nuclear Information System (INIS)

Leaw, W.L.; Mamat, C.R.; Triwahyono, S.; Jalil, A.A.; Bidin, N.

2016-01-01

Liquid crystal physical gels were (thermally) prepared with cholesteryl stearate as a gelator in nematic liquid crystal, 4-cyano-4′-pentylbiphenyl. The electro-optical performance of liquid crystal physical gels is almost entirely dependent on the gels' inherent morphology. This study involved an empirical investigation of the relationships among all of the gelation temperature, morphology, and electro-optical properties. Besides continuous cooling at room temperature, isothermal cooling was also performed at both 18 and 0 °C, corresponding to near-solid and solid phases of 4-cyano-4′-pentylbiphenyl respectively. Nevertheless, the liquid crystal physical gel was also isothermally rapidly cooled using liquid nitrogen. Polarizing optical microscopy showed that the gel structure became thinner when isothermal cooling was carried out. These thinner gel aggregates then interconnected to form larger liquid crystal domains. Moreover, it was also revealed that the gel networks were randomized. Electron spin resonance results showed that the liquid crystal director orientation was severely randomized in the presence of gel networks. Conversely, isothermal cooling using liquid nitrogen generated a higher liquid crystal director orientation order. The 6.0 wt% cholesteryl stearate/4-cyano-4′-pentylbiphenyl physical gel that was isothermally cooled using liquid nitrogen showed the lowest response time in a twisted nematic mode optical cell. - Graphical abstract: Liquid crystal physical gel was prepared using nematic liquid crystal, 4-cyano-4′-pentylbiphenyl and cholesteryl stearate as gelator. Isothermal cooling at lower temperature produced thinner gel network and larger liquid crystal domain. - Highlights: • 5CB nematic liquid crystal was successfully gelled by cholesteryl stearate gelator. • The morphology of gel network was controlled by different cooling conditions. • Thinner gel network was formed by the rapid cooling using liquid nitrogen. • Enhanced

Effect of temperature on the morphology and electro-optical properties of liquid crystal physical gel

Energy Technology Data Exchange (ETDEWEB)

Leaw, W.L. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Mamat, C.R., E-mail: che@kimia.fs.utm.my [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Triwahyono, S. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Jalil, A.A. [Department of Chemical Engineering, Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Centre of Hydrogen Energy, Institute of Future Energy, Univerisiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Bidin, N. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia)

2016-12-01

Liquid crystal physical gels were (thermally) prepared with cholesteryl stearate as a gelator in nematic liquid crystal, 4-cyano-4′-pentylbiphenyl. The electro-optical performance of liquid crystal physical gels is almost entirely dependent on the gels' inherent morphology. This study involved an empirical investigation of the relationships among all of the gelation temperature, morphology, and electro-optical properties. Besides continuous cooling at room temperature, isothermal cooling was also performed at both 18 and 0 °C, corresponding to near-solid and solid phases of 4-cyano-4′-pentylbiphenyl respectively. Nevertheless, the liquid crystal physical gel was also isothermally rapidly cooled using liquid nitrogen. Polarizing optical microscopy showed that the gel structure became thinner when isothermal cooling was carried out. These thinner gel aggregates then interconnected to form larger liquid crystal domains. Moreover, it was also revealed that the gel networks were randomized. Electron spin resonance results showed that the liquid crystal director orientation was severely randomized in the presence of gel networks. Conversely, isothermal cooling using liquid nitrogen generated a higher liquid crystal director orientation order. The 6.0 wt% cholesteryl stearate/4-cyano-4′-pentylbiphenyl physical gel that was isothermally cooled using liquid nitrogen showed the lowest response time in a twisted nematic mode optical cell. - Graphical abstract: Liquid crystal physical gel was prepared using nematic liquid crystal, 4-cyano-4′-pentylbiphenyl and cholesteryl stearate as gelator. Isothermal cooling at lower temperature produced thinner gel network and larger liquid crystal domain. - Highlights: • 5CB nematic liquid crystal was successfully gelled by cholesteryl stearate gelator. • The morphology of gel network was controlled by different cooling conditions. • Thinner gel network was formed by the rapid cooling using liquid nitrogen. �

Liquid crystal television spatial light modulators

Science.gov (United States)

Liu, Hua-Kuang; Chao, Tien-Hsin

1989-01-01

The spatial light modulation characteristics and capabilities of the liquid crystal television (LCTV) spatial light modulators (SLMs) are discussed. A comparison of Radio Shack, Epson, and Citizen LCTV SLMs is made.

(Liquid + liquid) equilibria for (water + 1-propanol or acetone + β-citronellol) at different temperatures

International Nuclear Information System (INIS)

Li, Hengde; Han, Yongtao; Huang, Cheng; Yang, Chufen

2015-01-01

Graphical abstract: (Liquid + liquid) equilibrium data for systems composed of β-citronellol and aqueous 1-propanol or acetone are presented. Distribution ratios of 1-propanol and acetone in the mixtures are examined. The effect of the temperature on the ternary (liquid + liquid) equilibria is evaluated and discussed. - Highlights: • Ternary (liquid + liquid) equilibria containing β-citronellol are presented. • Distribution ratios of 1-propanol and acetone in the mixtures are examined. • The effect on the temperature of the systems is evaluated and discussed. - Abstract: On this paper, experimental (liquid + liquid) equilibrium (LLE) results are presented for systems composed of β-citronellol and aqueous 1-propanol or acetone. To evaluate the phase separation properties of β-citronellol in aqueous mixtures, LLE values for the ternary systems (water + 1-propanol + β-citronellol) and (water + acetone + β-citronellol) were determined with a tie-line method at T = (283.15, 298.15, and 313.15 ± 0.02) K and atmospheric pressure. The reliability of the experimental tie-lines was verified by the Hand and Bachman equations. Ternary phase diagrams, distribution ratios of 1-propanol and acetone in the mixtures are shown. The effect of the temperature on the ternary (liquid + liquid) equilibria was examined and discussed. The experimental LLE values were satisfactorily correlated by extended UNIQUAC and modified UNIQUAC models

Vitrification and Crystallization of Phase-Separated Metallic Liquid

Directory of Open Access Journals (Sweden)

Yun Cheng

2017-02-01

Full Text Available The liquid–liquid phase separation (LLPS behavior of Fe50Cu50 melt from 3500 K to 300 K with different rapid quenching is investigated by molecular dynamics (MD simulation based on the embedded atom method (EAM. The liquid undergoes metastable phase separation by spinodal decomposition in the undercooled regime and subsequently solidifies into three different Fe-rich microstructures: the interconnected-type structure is kept in the glass and crystal at a higher cooling rate, while the Fe-rich droplets are found to crystalize at a lower cooling rate. During the crystallization process, only Fe-rich clusters can act as the solid nuclei. The twinning planes can be observed in the crystal and only the homogeneous atomic stacking shows mirror symmetry along the twinning boundary. Our present work provides atomic-scale understanding of LLPS melt during the cooling process.

Variational Approach in the Theory of Liquid-Crystal State

Science.gov (United States)

Gevorkyan, E. V.

2018-03-01

The variational calculus by Leonhard Euler is the basis for modern mathematics and theoretical physics. The efficiency of variational approach in statistical theory of liquid-crystal state and in general case in condensed state theory is shown. The developed approach in particular allows us to introduce correctly effective pair interactions and optimize the simple models of liquid crystals with help of realistic intermolecular potentials.

Smectic liquid crystals in anisotropic colloidal silica gels

Energy Technology Data Exchange (ETDEWEB)

Liang, Dennis [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Borthwick, Matthew A [Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Leheny, Robert L [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)

2004-05-19

We report x-ray scattering studies of the smectic liquid crystal octylcyano-biphenol (8CB) confined by strained colloidal silica gels. The gels, comprised of aerosil particles, possess an anisotropic structure that stabilizes long-range nematic order in the liquid crystal while introducing random field effects that disrupt the smectic transition. The short-range smectic correlations that form within this environment are inconsistent with the presence of a topologically ordered state predicted for 3D random field XY systems and are quantitatively like the correlations of smectics confined by isotropic gels. Detailed analysis reveals that the quenched disorder suppresses the anisotropic scaling of the smectic correlation lengths observed in the pure liquid crystal. These results and additional measurements of the smectic-A to smectic-C transition in 4-n-pentylphenylthiol-4'-n-octyloxybenzoate (8barS5) indicate that the observed smectic behaviour is dictated by random fields coupling directly to the smectic order while fields coupling to the nematic director play a subordinate role.

Guided mode studies of smectic liquid crystals

International Nuclear Information System (INIS)

Hodder, B.

2000-03-01

Recently there has been considerable interest in the use of ferroelectric liquid crystals in low power, fast switching display devices. At present the voltage switching process in surface stabilised ferroelectric liquid crystal (SSFLC) devices is not fully understood and a convenient theory for such cells has yet to be found. It is the primary aim of this work to characterise the optic tensor configuration (director profile) in thin cells (∼ 3.5 μm) containing ferroelectric liquid crystal (FLC) material. These results form a benchmark by which continuum theories may be tested. Polarised microscopy is, perhaps, the most common optical probe of liquid crystal cells. It should be appreciated that this technique is fundamentally limited, as the results are deduced from an integrated optical response of any given cell, and cannot be used to spatially resolve details of the director profile through the cell. The guided mode techniques used in this study are the primary non-integral probe and enable detailed spatial resolution of the director profile within liquid crystal cells. Analysis of guided mode data from cells containing homeotropically aligned FLC reveals the temperature dependence of the optical biaxiality and cone angle for a 40% chiral mixture of the commercially available FLC SCE8*. From these optical biaxiality measurements the temperature dependence of the biaxial order parameter C is determined. Guided mode studies of cells containing homogeneously aligned SCE8* (the conventional alignment for SSFLC devices) reveal the 0V equilibrium director profile from which a cone and chevron model is constructed. Subsequent studies of voltage induced elastic deformations of the director profile are presented and compared with a single elastic constant continuum theory which is shown to be inadequate. Optical guided mode techniques are not directly sensitive to the smectic layer configuration but X-ray scattering is. Here, for the first time, results are presented

Liquid filling of photonic crystal fibres for grating writing

DEFF Research Database (Denmark)

Sørensen, Henrik Rokkjær; Canning, John; Lægsgaard, Jesper

2007-01-01

liquid filling of photonic crystal fibres reduces the scattering from air–glass interfaces during Bragg grating writing in many layered photonic crystal fibres. Within experimental uncertainty, the grating index modulation of a grating written in germanium-doped photonic crystal fibre with 10 rings...

Measurements and correlation of liquid-liquid equilibrium data for the ternary (3-heptanone + phenol + water) system

International Nuclear Information System (INIS)

Xu, Gaojie; Yang, Deling; Ning, Pengge; Wang, Qingjie; Gong, Fuchun; Cao, Hongbin

2017-01-01

Highlights: • The liquid-liquid equilibrium data for 3-heptanone + phenol + water were measured. • The distribution coefficient of phenol and selectivity for solvent extraction efficiency were calculated. • The NRTL model (two regression methods) and UNIQUAC model were used to correlate the experimental data with good results. • The physical meaning of the regressed binary parameters was explained by intermolecular attractive energy. • The activity coefficient of phenol and enthalpy change in extraction process were investigated. - Abstract: Liquid-liquid equilibrium (LLE) for the ternary (3-heptanone + phenol + water) system has been determined under atmospheric pressure at 298.15 K, 303.15 K, 318.15 K and 323.15 K. The NRTL and UNIQUAC models were used to correlate the experimental results. The corresponding binary parameters were obtained and their physical meaning is explained by intermolecular attractive energy. The results from the two models agree well with experimental values. The NRTL model was more accurate than that of the UNIQUAC model. Meanwhile, the NRTL model was used to regress all the experimental values at different temperatures simultaneously, which is defined as total-regression. Compared with the individual regression by the NRTL model, the total regression by the NRTL model has fewer parameters and covers a wider interpolated range from 298.15 K to 323.15 K. The distribution coefficient for phenol changes with temperature. The phenol concentration can be expressed as a function of activity coefficient of phenol in both phases. The effect of temperature on the extraction performance of 3-heptanone was also investigated. The phenol extraction process by 3-heptanone is exothermic. The increase of temperature is not a benefit to phenol extraction.

Development of dispersive liquid-liquid microextraction technique using ternary solvents mixture followed by heating for the rapid and sensitive analysis of phthalate esters and di(2-ethylhexyl) adipate.

Science.gov (United States)

Farajzadeh, Mir Ali; Khoshmaram, Leila

2015-01-30

In this study, for the first time, a dispersive liquid-liquid microextraction technique using a ternary solvent mixture is reported. In order to extract five phthalate esters and di(2-ethylhexyl) adipate with different polarities from aqueous samples, a simplex centroid experimental design method was used to select an optimal mixture of ternary solvents prior to gas chromatographyflame ionization detection. In this work, dimethyl formamide as a disperser solvent containing dichloromethane, chloroform, and carbon tetrachloride as a ternary extraction solvent mixture is injected into sample solution and a cloudy solution is formed. After centrifuging, 250μL of the obtained sedimented phase was transferred into another tube and 5μL DMF was added to it. Then, the tube was heated in a water bath at 75°C for 5min in order to evaporate the main portion of the extraction solvents. Finally, 2μL of the remained phase is injected into the separation system. Under the optimum extraction conditions, the method shows wide linear ranges and low limits of detection and quantification between 0.03-0.15 and 0.09-0.55μgL(-1), respectively. Enrichment factors and extraction recoveries are in the ranges of 980-4500 and 20-90%, respectively. The method is successfully applied in the determination of the target analytes in mineral water, soda, lemon juice, vinegar, dough, and yogurt packed in plastic packages. Copyright © 2014 Elsevier B.V. All rights reserved.

Ternary Vapor–Liquid Equilibrium Measurements and Modeling of Ethylene Glycol (1) + Water (2) + Methane (3) Systems at 6 and 12.5 MPa

DEFF Research Database (Denmark)

Kruger, Francois J.; Danielsen, Marie V.; Kontogeorgis, Georgios M.

2018-01-01

Novel technologies in the field of subsea gasprocessing include the development of natural gas dehydration facilities, which may operate at high pressure due to their proximity to reservoirs. For the qualification and design of these processing units, ternary vapor−liquid equilibrium data...... are required to validate the thermodynamic models used in the design process. For this purpose, 16 new ternary data points were measured for ethylene glycol (1) + water (2) + methane (3) at 6.0 and 12.5 MPa with temperatures ranging from 288to 323 K and glycol content above 90 wt %. Glycol in gas (y1),water...

2D director calculation for liquid crystal optical phased array

International Nuclear Information System (INIS)

Xu, L; Zhang, J; Wu, L Y

2005-01-01

A practical numerical model for a liquid crystal cell is set up based on the geometrical structure of liquid crystal optical phased arrays. Model parameters include width and space of electrodes, thickness of liquid crystal layer, alignment layers and glass substrates, pre-tilted angles, dielectric constants, elastic constants and so on. According to electrostatic field theory and Frank-Oseen elastic continuum theory, 2D electric potential distribution and 2D director distribution are calculated by means of the finite difference method on non-uniform grids. The influence of cell sizes on director distribution is analyzed. The fringe field effect between electrodes is also discussed

Liquid Crystal Gel Reduces Age Spots by Promoting Skin Turnover

OpenAIRE

Mina Musashi; Ariella Coler-Reilly; Teruaki Nagasawa; Yoshiki Kubota; Satomi Kato; Yoko Yamaguchi

2014-01-01

Studies have shown that liquid crystals structurally resembling the intercellular lipids in the stratum corneum can beneficially affect the skin when applied topically by stimulating the skin’s natural regenerative functions and accelerating epidermal turnover. In the present study, the effects of applying low concentrations of a liquid crystal gel of our own creation were evaluated using epidermal thickening in mouse skin as an assay for effective stimulation of epidermal turnover. A liquid ...

Creation of tunable absolute bandgaps in a two-dimensional anisotropic photonic crystal modulated by a nematic liquid crystal

International Nuclear Information System (INIS)

Liu Chenyang

2008-01-01

Photonic crystals (PCs) have many potential applications because of their ability to control light-wave propagation. We have investigated the tunable absolute bandgap in a two-dimensional anisotropic photonic crystal structures modulated by a nematic liquid crystal. The PC structure composed of an anisotropic-dielectric cylinder in the liquid crystal medium is studied by solving Maxwell's equations using the plane wave expansion method. The photonic band structures are found to exhibit absolute bandgaps for the square and triangular lattices. Numerical simulations show that the absolute bandgaps can be continuously tuned in the square and triangular lattices consisting of anisotropic-dielectric cylinders by infiltrating nematic liquid crystals. Such a mechanism of bandgap adjustment should open up a new application for designing components in photonic integrated circuits

Thermal Conductivity and Liquid Crystal Thermometers.

Science.gov (United States)

Edge, R. D., Ed.

1993-01-01

Describes using stock liquid crystal postcards as inexpensive classroom thermometers. Also suggests using these postcards as a good visual temperature indicator for classroom demonstrations such as temperature gradients. One such activity is provided. (MVL)

Precipitation of thin-film organic single crystals by a novel crystal growth method using electrospray and ionic liquid film

Science.gov (United States)

Ueda, Hiroyuki; Takeuchi, Keita; Kikuchi, Akihiko

2018-04-01

We report an organic single crystal growth technique, which uses a nonvolatile liquid thin film as a crystal growth field and supplies fine droplets containing solute from the surface of the liquid thin film uniformly and continuously by electrospray deposition. Here, we investigated the relationships between the solute concentration of the supplied solution and the morphology and size of precipitated crystals for four types of fluorescent organic low molecule material [tris(8-hydroxyquinoline)aluminum (Alq3), 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD), N,N‧-bis(3-methylphenyl)-N,N‧-diphenylbenzidine (TPD), and N,N-bis(naphthalene-1-yl)-N,N-diphenyl-benzidine (NPB)] using an ionic liquid as the nonvolatile liquid. As the concentration of the supplied solution decreased, the morphology of precipitated crystals changed from dendritic or leaf shape to platelike one. At the solution concentration of 0.1 mg/ml, relatively large platelike single crystals with a diagonal length of over 100 µm were obtained for all types of material. In the experiment using ionic liquid and dioctyl sebacate as nonvolatile liquids, it was confirmed that there is a clear positive correlation between the maximum volume of the precipitated single crystal and the solubility of solute under the same solution supply conditions.

Binary and ternary cocrystals of sulfa drug acetazolamide with pyridine carboxamides and cyclic amides.

Science.gov (United States)

Bolla, Geetha; Nangia, Ashwini

2016-03-01

A novel design strategy for cocrystals of a sulfonamide drug with pyridine carboxamides and cyclic amides is developed based on synthon identification as well as size and shape match of coformers. Binary adducts of acetazolamide (ACZ) with lactams (valerolactam and caprolactam, VLM, CPR), cyclic amides (2-pyridone, labeled as 2HP and its derivatives MeHP, OMeHP) and pyridine amides (nicotinamide and picolinamide, NAM, PAM) were obtained by manual grinding, and their single crystals by solution crystallization. The heterosynthons in the binary cocrystals of ACZ with these coformers suggested a ternary combination for ACZ with pyridone and nicotinamide. Novel supramolecular synthons of ACZ with lactams and pyridine carboxamides are reported together with binary and ternary cocrystals for a sulfonamide drug. This crystal engineering study resulted in the first ternary cocrystal of acetazolamide with amide coformers, ACZ-NAM-2HP (1:1:1).

Crystal-liquid-gas phase transitions and thermodynamic similarity

CERN Document Server

Skripov, Vladimir P; Schmelzer, Jurn W P

2006-01-01

Professor Skripov obtained worldwide recognition with his monograph ""Metastable liquids"", published in English by Wiley & Sons. Based upon this work and another monograph published only in Russia, this book investigates the behavior of melting line and the properties of the coexisting crystal and liquid phase of simple substances across a wide range of pressures, including metastable states of the coexisting phases. The authors derive new relations for the thermodynamic similarity for liquid-vapour phase transition, as well as describing solid-liquid, liquid-vapor and liquid-liquid phase tra

Dichroic dye-dependent studies in guest-host polymer-dispersed liquid crystal films

Energy Technology Data Exchange (ETDEWEB)

Malik, Praveen, E-mail: pmalik100@yahoo.co [Department of Physics, Dr. B.R. Ambedkar National Institute of Technology, Jalandhar 144011, Punjab (India); Raina, K.K. [Liquid Crystal Group, Materials Research Laboratory, School of Physics and Materials Science, Thapar University, Patiala 147004, Punjab (India)

2010-01-01

Guest-host polymer-dispersed liquid crystal (GHPDLC) films were prepared using a nematic liquid crystal, photo-curable polymer and dichroic dye (anthraquinone blue) by polymerization-induced phase separation (PIPS) technique. Non-ionic dichroic dye (1%, 2% and 4% wt./wt. ratio) was taken as guest in PDLC host. Polarizing microscopy shows that in the absence of electric field, liquid crystal (LC) droplets in polymer matrix mainly exhibit bipolar configuration, however, relatively at higher field, maltese-type crosses were observed. Our results show that approx1% dye-doped PDLC film shows better transmission and faster response times over pure polymer-dispersed nematic liquid crystal (PDNLC) and higher concentrated (2% and 4%) GHPDLC films.

Dichroic dye-dependent studies in guest-host polymer-dispersed liquid crystal films

International Nuclear Information System (INIS)

Malik, Praveen; Raina, K.K.

2010-01-01

Guest-host polymer-dispersed liquid crystal (GHPDLC) films were prepared using a nematic liquid crystal, photo-curable polymer and dichroic dye (anthraquinone blue) by polymerization-induced phase separation (PIPS) technique. Non-ionic dichroic dye (1%, 2% and 4% wt./wt. ratio) was taken as guest in PDLC host. Polarizing microscopy shows that in the absence of electric field, liquid crystal (LC) droplets in polymer matrix mainly exhibit bipolar configuration, however, relatively at higher field, maltese-type crosses were observed. Our results show that ∼1% dye-doped PDLC film shows better transmission and faster response times over pure polymer-dispersed nematic liquid crystal (PDNLC) and higher concentrated (2% and 4%) GHPDLC films.

IR Sensor Synchronizing Active Shutter Glasses for 3D HDTV with Flexible Liquid Crystal Lenses

Directory of Open Access Journals (Sweden)

Jeong In Han

2013-12-01

Full Text Available IR sensor synchronizing active shutter glasses for three-dimensional high definition television (3D HDTV were developed using a flexible liquid crystal (FLC lens. The FLC lens was made on a polycarbonate (PC substrate using conventional liquid crystal display (LCD processes. The flexible liquid crystal lens displayed a maximum transmission of 32% and total response time of 2.56 ms. The transmittance, the contrast ratio and the response time of the flexible liquid crystal lens were superior to those of glass liquid crystal lenses. Microcontroller unit and drivers were developed as part of a reception module with power supply for the IR sensor synchronizing active shutter glasses with the flexible liquid crystal lens prototypes. IR sensor synchronizing active shutter glasses for 3D HDTV with flexible liquid crystal lenses produced excellent 3D images viewing characteristics.

The liquid protein phase in crystallization: a case study—intact immunoglobulins

Science.gov (United States)

Kuznetsov, Yurii G.; Malkin, Alexander J.; McPherson, Alexander

2001-11-01

A common observation by protein chemists has been the appearance, for many proteins in aqueous solutions, of oil like droplets, or in more extreme cases the formation of a second oil like phase. These may accompany the formation of precipitate in "salting out" or "salting in' procedures, but more commonly appear in place of any precipitate. Such phase separations also occur, with even greater frequency, in the presence of polymeric precipitants such as polyethyleneglycol (PEG). In general the appearance of a second liquid phase has been taken as indicative of protein aggregation, though an aggregate state distinctly different from that characteristic of amorphous precipitate. While the latter is thought to be composed of linear and branched assemblies, polymers of a sort, the oil phase suggests a more compact, three-dimensional, but fluid state. An important property of an alternate, fluid phase is that it can mediate transitions between other states, for example, between protein molecules free in solution and protein molecules immobilized in amorphous precipitate or crystals. The "liquid protein" phase can be readily observed in many crystallization experiments either prior to the appearance of visible crystals, or directly participating in the crystal growth process. In some cases the relationship between the liquid phase and developing crystals is intimate. Crystals grow directly from the liquid phase, or appear only after the visible formation of the liquid phase. We describe here our experience with a class of macromolecules, immunoglobulins, and particularly IDEC-151, an IgG specific for CD4 on human lymphocytes. This protein has been crystallized from a Jeffamine-LiSO 4 mother liquor and, its crystallization illustrates many of the features associated with the liquid protein, or protein rich phase.

Experimental determination of the phase equilibria in the Co-Fe-Zr ternary system

International Nuclear Information System (INIS)

Wang, C.P.; Yu, Y.; Zhang, H.H.; Hu, H.F.; Liu, X.J.

2011-01-01

Research highlights: → We determined four isothermal sections of the Co-Fe-Zr system from 1000 o C to 1300 o C. → No ternary compound was found in the Co-Fe-Zr ternary system. → The solubility of Fe in the liquid phase at 1300 o C is extremely large. → The (Co, Fe) 2 Zr phase form the continuous solution from Co-Zr side to Fe-Zr side. → The solubility of Zr in the fcc (Co, Fe) phase is extremely small. - Abstract: The phase equilibria in the Co-Fe-Zr ternary system were investigated by means of optical microscopy (OM), electron probe microanalysis (EPMA), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) on equilibrated ternary alloys. Four isothermal sections of the Co-Fe-Zr ternary system at 1300 o C, 1200 o C, 1100 o C and 1000 o C were experimentally established. The experimental results indicate that (1) no ternary compound was found in this system; (2) the solubility of Fe in the liquid phase of the Co-rich corner at 1300 o C is extremely large; (3) the liquid phase in the Zr-rich corner and the (Co,Fe) 2 Zr phase form the continuous solid solutions from the Co-Zr side to the Fe-Zr side; (4) the solubility of Zr in the fcc (Co, Fe) phase is extremely small.

(Vapour + liquid) equilibria in the ternary system (acetonitrile + n-propanol + ethylene glycol) and corresponding binary systems at 101.3 kPa

International Nuclear Information System (INIS)

Qian, Guo-fei; Liu, Wen; Wang, Li-tao; Wang, Dao-cai; Song, Hang

2013-01-01

Highlights: • We adopted a new extractive solvent “ethylene glycol” to separate the mixture. • We measured the VLE data of binary system n-propanol + ethylene glycol. • We reinforce the VLE data of binary system acetonitrile + ethylene glycol. • We predicted the VLE data for the ternary system successfully. -- Abstract: Experimental isobaric (Vapour + liquid) equilibrium (VLE) data at 101.3 kPa were determined for three binary systems, viz. {acetonitrile (1) + n-propanol (2)}, {acetonitrile (1) + ethylene glycol (3)} and {n-propanol (2) + ethylene glycol (3)} and for one ternary system {acetonitrile (1) + n-propanol (2) + ethylene glycol (3)}. The measurements were performed using an improved Rose equilibrium still. The VLE data of the binary systems passed thermodynamic consistency tests and were correlated by Wilson and NRTL models. Good results were achieved. The phase behaviour of the ternary system was predicted directly by the parameters of two models obtained from the experimental binary results. The results showed an excellent agreement with experimental values

Optimized Wavelength-Tuned Nonlinear Frequency Conversion Using a Liquid Crystal Clad Waveguide

Science.gov (United States)

Stephen, Mark A. (Inventor)

2018-01-01

An optimized wavelength-tuned nonlinear frequency conversion process using a liquid crystal clad waveguide. The process includes implanting ions on a top surface of a lithium niobate crystal to form an ion implanted lithium niobate layer. The process also includes utilizing a tunable refractive index of a liquid crystal to rapidly change an effective index of the lithium niobate crystal.

Solid–liquid equilibria for binary and ternary systems with the Cubic-Plus-Association (CPA) equation of state

DEFF Research Database (Denmark)

Fettouhi, André; Thomsen, Kaj

2010-01-01

A systematic investigation of the CPA model's performance within solid-liquid equilibria (SLE) in binary mixtures (methane + ethane, methane + heptane, methane + benzene, methane + CO2, ethane + heptane, ethane + CO2, 1-propanol + 1,4-dioxane, ethanol + water, 2-propanol + water) is presented. Th....... The results from the binary mixtures are used to predict SLE behaviour in ternary mixtures (methane + ethane + heptane, methane + ethane + CO2). Our results are compared with experimental data found in the literature....

A dark hollow beam from a selectively liquid-filled photonic crystal fibre

International Nuclear Information System (INIS)

Mei-Yan, Zhang; Shu-Guang, Li; Yan-Yan, Yao; Bo, Fu; Lei, Zhang

2010-01-01

This paper reports that, based on the electromagnetic scattering theory of the multipole method, a high-quality hollow beam is produced through a selectively liquid-filled photonic crystal fibre. Instead of a doughnut shape, a typical hollow beam is produced by other methods; the mode-field images of the hollow-beam photonic crystal fibre satisfy sixth-order rotation symmetry, according to the symmetry of the photonic crystal fibre (PCF) structure. A dark spot size of the liquid-filled photonic crystal fibre-generated hollow beam can be tuned by inserting liquid into the cladding region and varying the photonic crystal fibre structure parameters. The liquid-filled PCF makes a convenient and flexible tool for the guiding and trapping of atoms and the creation of all-fibre optical tweezers. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Liquid Crystal Gel Reduces Age Spots by Promoting Skin Turnover

Directory of Open Access Journals (Sweden)

Mina Musashi

2014-07-01

Full Text Available Studies have shown that liquid crystals structurally resembling the intercellular lipids in the stratum corneum can beneficially affect the skin when applied topically by stimulating the skin’s natural regenerative functions and accelerating epidermal turnover. In the present study, the effects of applying low concentrations of a liquid crystal gel of our own creation were evaluated using epidermal thickening in mouse skin as an assay for effective stimulation of epidermal turnover. A liquid crystal gel was also applied topically to human facial skin, and analysis was conducted using before-and-after photographs of age spots, measurements of L* values that reflect degree of skin pigmentation, single-layer samples of the stratum corneum obtained via tape-stripping, and measurements of trans-epidermal water loss that reflect the status of the skin’s barrier function. The results suggested that cost-effective creams containing as low as 5% liquid crystal gel might be effective and safely sold as skin care products targeting age spots and other problems relating to uneven skin pigmentation.

Liquid-Crystal Thermosets, a New Generation of High-Performance Liquid-Crystal Polymers

Science.gov (United States)

Dingemans, Theo; Weiser, Erik; Hou, Tan; Jensen, Brian; St. Clair, Terry

2004-01-01

One of the major challenges for NASA's next-generation reusable-launch-vehicle (RLV) program is the design of a cryogenic lightweight composite fuel tank. Potential matrix resin systems need to exhibit a low coefficient of thermal expansion (CTE), good mechanical strength, and excellent barrier properties at cryogenic temperatures under load. In addition, the resin system needs to be processable by a variety of non-autoclavable techniques, such as vacuum-bag curing, resin-transfer molding (RTM), vacuum-assisted resin-transfer molding (VaRTM), resin-film infusion (RFI), pultrusion, and advanced tow placement (ATP). To meet these requirements, the Advanced Materials and Processing Branch (AMPB) at NASA Langley Research Center developed a new family of wholly aromatic liquid-crystal oligomers that can be processed and thermally cross-linked while maintaining their liquid-crystal order. All the monomers were polymerized in the presence of a cross-linkable unit by use of an environmentally benign melt-condensation technique. This method does not require hazardous solvents, and the only side product is acetic acid. The final product can be obtained as a powder or granulate and has an infinite shelf life. The obtained oligomers melt into a nematic phase and do not exhibit isotropization temperatures greater than the temperatures of decomposition (Ti > T(sub dec)). Three aromatic formulations were designed and tested and included esters, ester-amides, and ester-imides. One of the major advantages of this invention, named LaRC-LCR or Langley Research Center-Liquid Crystal Resin, is the ability to control a variety of resin characteristics, such as melting temperature, viscosity, and the cross-link density of the final part. Depending on the formulation, oligomers can be prepared with melt viscosities in the range of 10-10,000 poise (100 rad/s), which can easily be melt-processed using a variety of composite-processing techniques. This capability provides NASA with custom

Thin aligned organic polymer films for liquid crystal devices

International Nuclear Information System (INIS)

Foster, Kathryn Ellen

1997-01-01

This project was designed to investigate the possibility of producing alignment layers for liquid crystal devices by cross-linking thin films containing anisotropic polymer bound chromophores via irradiation with polarised ultraviolet light. Photocross-linkable polymers find use in microelectronics, liquid crystal displays, printing and UV curable lacquers and inks; so there is an increasing incentive for the development of new varieties of photopolymers in general. The synthesis and characterisation of two new photopolymers that are suitable as potential alignment layers for liquid crystal devices are reported in this thesis. The first polymer contains the anthracene chromophore attached via a spacer unit to a methacrylate backbone and the second used a similarly attached aryl azide group. Copolymers of the new monomers with methyl methacrylate were investigated to establish reactivity ratios in order to understand composition drift during polymerisation. (author)

The new ternary pnictides Er12Ni30P21 and Er13Ni25As19: Crystal structures and magnetic properties

International Nuclear Information System (INIS)

Oryshchyn, Stepan; Babizhetskyy, Volodymyr; Zhak, Olga; Zelinska, Mariya; Pivan, Jean-Yves; Duppel, Viola; Simon, Arndt; Kienle, Lorenz

2010-01-01

The new ternary pnictides Er 12 Ni 30 P 21 and Er 13 Ni 25 As 19 have been synthesized from the elements. They crystallize with hexagonal structures determined from single-crystal X-ray data for Er 12 Ni 30 P 21 (space group P6 3 /m, a=1.63900(3) nm, c=0.37573(1) nm, Z=1, R F =0.062 for 1574 F-values and 74 variable parameters), and for Er 13 Ni 25 As 19 (Tm 13 Ni 25 As 19 -type structure, space group P6-bar , a=1.6208(1) nm, c=0.38847(2) nm, Z=1, R F =0.026 for 1549 F-values and 116 variable parameters). These compounds belong to a large family of hexagonal structures with a metal-metalloid ratio of 2:1. HRTEM investigations were conducted to probe for local ordering of the disordered structure at the nanoscale. The magnetic properties of the phosphide Er 12 Ni 30 P 21 have been studied in the temperature of range 2 eff =9.59 μ B corresponds to the theoretical value of Er 3+ . - Graphical abstract: The new ternary pnictides Er 12 Ni 30 P 21 and Er 13 Ni 25 As 19 have been synthesized from the elements. They crystallize with hexagonal structures determined from single-crystal X-ray data. The compounds belong to a large family of structures with a metal-metalloid ratio of 2:1. HRTEM investigations were conducted to probe for local ordering of the disordered structure at the nanoscale. Display Omitted

Spectroscopic investigation of the far-infrared properties of liquid crystals

DEFF Research Database (Denmark)

Reuter, M.; Vieweg, N.; Fischer, B. M.

2013-01-01

Liquid crystals are one of the most promising base materials for switchable devices at THz frequencies. Therefore, a precise understanding of the optical parameters is crucial. Here, we present the refractive indices and absorption coefficients for 5 CB and an isothiocyanate terminated liquid...... crystal over a broad frequency range from 0.3 THz to 15 THz....

The ternary systems Sc-Sm(Dy)-Si at 870 K

International Nuclear Information System (INIS)

Kotur, B.Ya.; Mokra, I.Ya.; Toporinskij, A.Ya.

1991-01-01

Isothermal cross sections of the ternary systems Sc-Sm-Si and Sc-Dy-Si at 870 K have been plotted. Investigation of scandium and disprosium in ternary systems have been examined by X-ray diffraction and microstructure analysis. Besides literary data on binary systems Sc-Si, Sm-Si, Dy-Si have been used. Formation of limited (Sc-Sm-Si, Sc-Dy-Si) and continuous (Sc-Dy-Si) solid solutions based on bisilicides of Sc and Sm(Dy) is discovered. Two and five ternary compounds in Sc-Sm-Si and Sc-Dy-Si systems have been determined and their crystal structure has been established. When investigating of Sc-(rare earth element)-Si ternary systems and should take into account the specific interaction of scandium and samarium with REE

Binary and ternary cocrystals of sulfa drug acetazolamide with pyridine carboxamides and cyclic amides

Directory of Open Access Journals (Sweden)

Geetha Bolla

2016-03-01

Full Text Available A novel design strategy for cocrystals of a sulfonamide drug with pyridine carboxamides and cyclic amides is developed based on synthon identification as well as size and shape match of coformers. Binary adducts of acetazolamide (ACZ with lactams (valerolactam and caprolactam, VLM, CPR, cyclic amides (2-pyridone, labeled as 2HP and its derivatives MeHP, OMeHP and pyridine amides (nicotinamide and picolinamide, NAM, PAM were obtained by manual grinding, and their single crystals by solution crystallization. The heterosynthons in the binary cocrystals of ACZ with these coformers suggested a ternary combination for ACZ with pyridone and nicotinamide. Novel supramolecular synthons of ACZ with lactams and pyridine carboxamides are reported together with binary and ternary cocrystals for a sulfonamide drug. This crystal engineering study resulted in the first ternary cocrystal of acetazolamide with amide coformers, ACZ–NAM–2HP (1:1:1.

Do protein crystals nucleate within dense liquid clusters?

International Nuclear Information System (INIS)

Maes, Dominique; Vorontsova, Maria A.; Potenza, Marco A. C.; Sanvito, Tiziano; Sleutel, Mike; Giglio, Marzio; Vekilov, Peter G.

2015-01-01

The evolution of protein-rich clusters and nucleating crystals were characterized by dynamic light scattering (DLS), confocal depolarized dynamic light scattering (cDDLS) and depolarized oblique illumination dark-field microscopy. Newly nucleated crystals within protein-rich clusters were detected directly. These observations indicate that the protein-rich clusters are locations for crystal nucleation. Protein-dense liquid clusters are regions of high protein concentration that have been observed in solutions of several proteins. The typical cluster size varies from several tens to several hundreds of nanometres and their volume fraction remains below 10 −3 of the solution. According to the two-step mechanism of nucleation, the protein-rich clusters serve as locations for and precursors to the nucleation of protein crystals. While the two-step mechanism explained several unusual features of protein crystal nucleation kinetics, a direct observation of its validity for protein crystals has been lacking. Here, two independent observations of crystal nucleation with the proteins lysozyme and glucose isomerase are discussed. Firstly, the evolutions of the protein-rich clusters and nucleating crystals were characterized simultaneously by dynamic light scattering (DLS) and confocal depolarized dynamic light scattering (cDDLS), respectively. It is demonstrated that protein crystals appear following a significant delay after cluster formation. The cDDLS correlation functions follow a Gaussian decay, indicative of nondiffusive motion. A possible explanation is that the crystals are contained inside large clusters and are driven by the elasticity of the cluster surface. Secondly, depolarized oblique illumination dark-field microscopy reveals the evolution from liquid clusters without crystals to newly nucleated crystals contained in the clusters to grown crystals freely diffusing in the solution. Collectively, the observations indicate that the protein-rich clusters in

Studies on ternary silver sulfides; Fukugo gin ryukabutsu ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-10-31

Some sulfides containing silver show high ion mobility based on movability of silver, whose application is expected. Studies have been carried out centrally on synthesis of new compounds of ternary silver sulfides by elucidating the relationship among their compositions, structures and properties by means of crystal chemical studies mainly on their phase relationship. A few new compounds have been synthesized, such as the ones having the argyrodite family compound structure including transition metals. The synthesizing process takes a kind of turbulent liquid state structure at elevated temperatures because of movability of silver, but silver is fixed at low temperatures in different sites between skeleton structures made by other atoms. These studies on phase transfer, structures, and silver movability have been based on X-ray diffraction, infrared and Raman spectroscopic measurements, NMR, measurements of electric and thermal characteristics. For the studies related to compositions and structures of ternary metal sulfides which take compound crystalline structure, a structure analyzing method based on multi-dimensional hyperspatial groups was used. This paper reports the summary of the studies in seven chapters, and dwells on the remaining problems and future prospects. 158 refs., 114 figs., 65 tabs.

Analytical determination of distillation boundaries for ternary azeotropic systems

OpenAIRE

Marcilla Gomis, Antonio; Reyes Labarta, Juan Antonio; Velasco, Raúl; Serrano Cayuelas, María Dolores; Olaya López, María del Mar

2009-01-01

A new straight forward algorithm to calculate distillation boundaries in ternary azeotropic systems has been developed. The proposed method allows, using cubic splines, the calculation of distillation trajectories and the calculation of that corresponding to the searched distillation boundaries. The algorithm is applied to 4 ternary liquid-vapour systems to test its validity. Vicepresidency of Research (University of Alicante) and Generalitat Valenciana (GV/2007/125)

Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

Energy Technology Data Exchange (ETDEWEB)

Kuehnel, Matthias

2014-02-15

This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

International Nuclear Information System (INIS)

Kuehnel, Matthias

2014-02-01

This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

Time-resolved crystallization of deeply cooled liquid hydrogen isotopes

Energy Technology Data Exchange (ETDEWEB)

Kuehnel, Matthias

2014-02-15

This thesis serves two main purposes: 1. The introduction of a novel experimental method to investigate phase change dynamics of supercooled liquids 2. First-time measurements for the crystallization behaviour for hydrogen isotopes under various conditions (1) The new method is established by the synergy of a liquid microjet of ∼ 5 μm diameter and a scattering technique with high spatial resolution, here linear Raman spectroscopy. Due to the high directional stability and the known velocity of the liquid filament, its traveling axis corresponds to a time axis static in space. Utilizing evaporative cooling in a vacuum environment, the propagating liquid cools down rapidly and eventually experiences a phase transition to the crystalline state. This temporal evolution is probed along the filament axis, ultimately resulting in a time resolution of 10 ns. The feasibility of this approach is proven successfully within the following experiments. (2) A main object of study are para-hydrogen liquid filaments. Raman spectra reveal a temperature gradient of the liquid across the filament. This behaviour can quantitatively be reconstructed by numerical simulations using a layered model and is rooted in the effectiveness of evaporative cooling on the surface and a finite thermal conductivity. The deepest supercoolings achieved are ∼ 30% below the melting point, at which the filament starts to solidify from the surface towards the core. With a crystal growth velocity extracted from the data the appropriate growth mechanism is identified. The crystal structure that initially forms is metastable and probably the result of Ostwald's rule of stages. Indications for a transition within the solid towards the stable equilibrium phase support this interpretation. The analog isotope ortho-deuterium is evidenced to behave qualitatively similar with quantitative differences being mass related. In further measurements, isotopic mixtures of para-hydrogen and ortho-deuterium are

Old and new ideas in ferroelectric liquid crystal technology

Science.gov (United States)

Lagerwall, Sven T.; Matuszczyk, M.; Matuszczyk, T.

1998-02-01

Ferroelectric liquid crystals (FLC) are to conventional liquid crystal what Gallium Arsenide is to Silicon in the semiconductor area. The first generation of FLC displays in now present on the market and has some outstanding features based on the symmetric bistability which may be achieved in these materials. One of the greatest challenges for the next generation is to achieve an analog grey scale out of an essentially digital principle. We will analyze in some detail which major problems had to be solved to reach the present state and show how the final steps could be taken toward a new state-of-the-art level in liquid crystal devices. In the last decade university research and industrial R and D have almost equally contributed to treat the very serious complications caused by the so-called chevron structures We will review this important topic in particular detail.

Ion Density Analysis of Single-Stranded DNA in Liquid Crystal

Science.gov (United States)

Iwabata, Kazuki; Seki, Yasutaka; Toizumi, Ryota; Shimada, Yuki; Furue, Hirokazu; Sakaguchi, Kengo

2013-09-01

With the widespread use of liquid crystals (LCs) in liquid crystal displays, we have looked into the application of liquid crystals in biotechnology. The purpose of the study described here is to investigate the physical properties of DNA using LCs. Synthetic oligonucleotide molecules were dispersed in MLC6884, the sample injected into antiparallel cells, and the amount of mobile ions was measured. The LC cell doped with oligonucleotide molecules showed a sequence-dependent, specific correlation between oligonucleotide concentration and the amount of mobile ions in the LC cells. In the framework of the Stokes model and polyacrylamide gel electrophoresis (PAGE) analysis, we speculate that this result arises from the difference in ion mobility, which is caused by the shape of the oligonucleotide molecule in the LC.

Measurement and correlation of (vapor + liquid) equilibrium data for {α-pinene + p-cymene + (S)-(−)-limonene} ternary system at atmospheric pressure

International Nuclear Information System (INIS)

Sun, Lixia; Liao, Dankui; Yang, Zhengyu; Chen, Xiaopeng; Tong, Zhangfa

2013-01-01

Highlights: ► The VLE data of (α-pinene + p-cymene) and (α-pinene + p-cymene + (S)-(−)-limonene) at atmospheric pressure were measured. ► The VLE data of binary system were correlated by four activity coefficient models. ► The ternary VLE data were predicted from binary parameters of the Liebermann–Fried model. ► The constant G 123 E counters plotted on the Roozeboom diagrams. -- Abstract: (Vapor + liquid) equilibrium (VLE) data for binary system of (α-pinene + p-cymene) and ternary system of {α-pinene + p-cymene + (S)-(−)-limonene} were measured at 100.7 kPa using the modified Ellis equilibrium still. The VLE data are thermodynamically consistent. Parameters of the binary system for the four solution models — Liebermann–Fried, Wilson, NRTL, and UNIQUAC — were calculated by referencing least squares method to minimize an objective function based on the total pressure. The ternary system data were predicted with the parameters of Liebermann–Fried model obtained from the pertinent binary systems. The predicted bubble-point temperature and the vapor composition for the ternary system were in good agreement with the experimental results. Smooth representations of the results are used to construct constant excess Gibbs free energy contours on Roozeboom diagrams

Ultraviolet-pumped liquid-crystal dye-laser

International Nuclear Information System (INIS)

Bertolotti, M.; Sbrolli, L.; Scudieri, F.; Papa, T.

1981-01-01

The possibility offered by the orientation properties of liquid crystals as a matrix for dye lasers is shown. In particular, the linear polarization of emitted light can be changed by acting with an external magnetic field on the molecular nematic director. (author)

Calculation of Optical Parameters of Liquid Crystals

Science.gov (United States)

Kumar, A.

2007-12-01

Validation of a modified four-parameter model describing temperature effect on liquid crystal refractive indices is being reported in the present article. This model is based upon the Vuks equation. Experimental data of ordinary and extraordinary refractive indices for two liquid crystal samples MLC-9200-000 and MLC-6608 are used to validate the above-mentioned theoretical model. Using these experimental data, birefringence, order parameter, normalized polarizabilities, and the temperature gradient of refractive indices are determined. Two methods: directly using birefringence measurements and using Haller's extrapolation procedure are adopted for the determination of order parameter. Both approches of order parameter calculation are compared. The temperature dependences of all these parameters are discussed. A close agreement between theory and experiment is obtained.

NMR studies of macroscopic and microscopic properties of liquid crystals

International Nuclear Information System (INIS)

Hughes, J.R.

1998-03-01

The work presented is concerned with studies of orientational order in liquid crystals and the behaviour of certain mesophases. The experimental technique used in common with all the work is deuterium NMR spectroscopy. Much of the work involves studies of the orientational order of deuteriated solute molecules dissolved in liquid crystal solvents. Chapter 1 gives an introduction to liquid crystals followed by a quantitative description of orientational order. Deuterium NMR in liquid crystals is described and an outline of the molecular field theory behind the orientational order of a rigid, biaxial solute in a uniaxial mesophase is given. In Chapter 2 a novel type of mesophase induction is studied using NMR, where a solute induces up to two extra phases in a discotic mesogen depending on its concentration. The purpose of this work is to try to gain an understanding into the mechanism of the phase induction involved. Chapter 3 is concerned primarily with the macroscopic behaviour of the nematic phase formed by a semi-rigid main-chain polymer in solution. Of particular interest is the study of the reorientation of the monodomain, once the director has been rotated with respect to the magnetic field of the NMR spectrometer. A mesogen which has been claimed to exhibit a biaxial nematic phase is studied in Chapter 4, in order to determine the symmetry of the phase using NMR. Finally, Chapter 5 deals with the differing behaviour of a liquid crystal monomer and its dimer dissolved in common nematic solvents in order to determine whether this agrees with molecular field theory. (author)

Chemistry of Discotic Liquid Crystals From Monomers to Polymers

CERN Document Server

Kumar, Sandeep

2010-01-01

Compiling the scattered literature into a single seminal work, this book describes the basic design principles, synthesis, and mesomorphic properties of discotic liquid crystals. Of fundamental importance as models for the study of energy and charge migration in self-organized systems, discotic liquid crystals find functional application as one-dimensional conductors, photoconductors, light emitting diodes, photovoltaic solar cells, field-effect transistors, and gas sensors. This book highlights the scientific concepts behind the hierarchical self-assembly of these disc-shaped molecules alongs

Bond orientational ordering in a metastable supercooled liquid: a shadow of crystallization and liquid–liquid transition

International Nuclear Information System (INIS)

Tanaka, Hajime

2010-01-01

It is widely believed that a liquid state can be characterized by a single order parameter, density, and that a transition from a liquid to solid can be described by density ordering (translational ordering). For example, this type of theory has had great success in describing the phase behaviour of hard spheres. However, there are some features that cannot be captured by such theories. For example, hard spheres crystallize into either hcp or fcc structures, without a tendency of bcc ordering which is expected by the Alexander–McTague theory based on the Landau-type free energy of the density order parameter. We also found hcp-like bond orientational ordering in a metastable supercooled liquid, which promotes nucleation of hcp crystals. Furthermore, theories based on the single order parameter cannot explain water-like thermodynamic and kinetic anomalies of a liquid and liquid–liquid transition in a single-component liquid. Based on these facts, we argue that we need an additional order parameter to describe a liquid state. It is bond orientational order, which is induced by dense packing in hard spheres or by directional bonding in molecular and atomic liquids. Bond orientational order is intrinsically of local nature, unlike translational order which is of global nature. This feature plays a unique role in crystallization and quasicrystal formation. We also reveal that bond orientational ordering is a cause of dynamic heterogeneity near a glass transition and is linked to slow dynamics. In relation to this, we note that, for describing the structuring of a highly disordered liquid, we need a structural signature of low configurational entropy, which is more general than bond orientational order. Finally, the water-like anomaly and liquid–liquid transition can be explained by bond orientational ordering due to hydrogen or covalent bonding and its cooperativity, respectively. So we argue that bond orientational ordering is a key to the physical understanding

The opto-thermal effect on encapsulated cholesteric liquid crystals

Science.gov (United States)

Liu, Yu-Sung; Lin, Hui-Chi; Yang, Kin-Min

2017-12-01

In this study, we implemented a micro-encapsulated CLC electronic paper that is optically addressed and electrically erasable. The mechanism that forms spot diameters on the CLC films is discussed and verified through various experimental parameters, including the thickness of CLCs and Poly(2,3-dihydrothieno-1,4-dioxin)-poly(styrenesulfonate) (PEDOT:PSS), pump intensity, and pumping time. The opto-thermal effect, brought on by the PEDOT:PSS absorbing layer, causes the spot diameters on the cholesteric liquid crystal thin films to vary. According to our results, the spot diameter is larger for a sample with a thinner cholesteric liquid crystal layer with the same excitation conditions and same thickness of the PEDOT layer. The spot diameter is also larger for a sample with a thicker PEDOT under the same excitation conditions and same thickness of the cholesteric liquid crystal layer. We proposed a simple heat-conducting model to explain the experimental results, which qualitatively agree with this theoretical model.

Ionic diffusion and salt dissociation conditions of lithium liquid crystal electrolytes.

Science.gov (United States)

Saito, Yuria; Hirai, Kenichi; Murata, Shuuhei; Kishii, Yutaka; Kii, Keisuke; Yoshio, Masafumi; Kato, Takashi

2005-06-16

Salt dissociation conditions and dynamic properties of ionic species in liquid crystal electrolytes of lithium were investigated by a combination of NMR spectra and diffusion coefficient estimations using the pulsed gradient spin-echo NMR techniques. Activation energies of diffusion (Ea) of ionic species changed with the phase transition of the electrolyte. That is, Ea of the nematic phase was lower than that of the isotropic phase. This indicates that the aligned liquid crystal molecules prepared efficient conduction pathways for migration of ionic species. The dissociation degree of the salt was lower compared with those of the conventional electrolyte solutions and polymer gel electrolytes. This is attributed to the low concentration of polar sites, which attract the dissolved salt and promote salt dissociation, on the liquid crystal molecules. Furthermore, motional restriction of the molecules due to high viscosity and molecular oriented configuration in the nematic phase caused inefficient attraction of the sites for the salt. With a decreased dissolved salt concentration of the liquid crystal electrolyte, salt dissociation proceeded, and two diffusion components attributed to the ion and ion pair were detected independently. This means that the exchange rate between the ion and the ion pair is fairly slow once the salt is dissociated in the liquid crystal electrolytes due to the low motility of the medium molecules that initiate salt dissociation.

Functional Smart Dispersed Liquid Crystals for Nano- and Biophotonic Applications: Nanoparticles-Assisted Optical Bioimaging

Directory of Open Access Journals (Sweden)

N. V. Kamanina

2016-01-01

Full Text Available Functional nematic liquid crystal structures doped with nano- and bioobjects have been investigated. The self-assembling features and the photorefractive parameters of the structured liquid crystals have been comparatively studied via microscopy and laser techniques. Fullerene, quantum dots, carbon nanotubes, DNA, and erythrocytes have been considered as the effective nano- and biosensitizers of the LC mesophase. The holographic recording technique based on four-wave mixing of the laser beams has been used to investigate the laser-induced change of the refractive index in the nano- and bioobjects-doped liquid crystal cells. The special accent has been given to novel nanostructured relief with vertically aligned carbon nanotubes at the interface: solid substrate-liquid crystal mesophase. It has been shown that this nanostructured relief influences the orienting ability of the liquid crystal molecules with good advantage. As a result, it provokes the orientation of the DNA. The modified functional liquid crystal materials have been proposed as the perspective systems for both the photonics and biology as well as the medical applications.

Evanescent Field Enhancement in Liquid Crystal Optical Fibers: A Field Characteristics Based Analysis

Directory of Open Access Journals (Sweden)

P. K. Choudhury

2013-01-01

Full Text Available The paper presents the analysis of the electromagnetic wave propagation through liquid crystal optical fibers (LCOFs of two different types—conventional guides loaded with liquid crystals (addressed as LCOFs and those with additional twists due to conducting helical windings (addressed as HCLCOFs. More precisely, the three-layer optical waveguide structures are considered along with its outermost region being loaded with radially anisotropic liquid crystal material and the inner regions being made of usual silica, as used in conventional optical fibers. In addition to that, LCOF with twists introduced in the form of conducting helical windings at the interface of the silica core and the liquid crystal clad is also taken into account. Emphasis has been put on the power confinements by the lower-order TE modes sustained in the different sections of the LCOF structure. The results demonstrate useful applications of these guides in integrated optics as the power sustained in the liquid crystal section by the excited TE modes remains very high. In the case of twisted clad liquid crystal guides, descriptions are limited to the nature of dispersion relation only under the TE mode excitation, and corresponding to the cases of helix orientations being parallel and perpendicular to the optical axis.

New ternary transition metal borides containing uranium and rare earth elements

International Nuclear Information System (INIS)

Rogl, P.; Delong, L.

1983-01-01

The new ternary actinide metal diborides U 2 MoB 6 , U 2 ReB 6 , U 2 OsB 6 , URuB 4 and UOsB 4 were prepared and found to crystallize with either the Y 2 ReB 6 or the ThMoB 4 type of structure. LuRuB 4 and LuOsB 4 crystallize with the YCrB 4 type of structure. In a ternary series of solid solutions YRh 3 Bsub(1-x) (0 0 C), boron was found to stabilize a Cu 3 Au type of structure. The superconductivity of the new uranium compounds and of a series of ternary transition metal borides was investigated; no superconductivity was observed for temperatures as low at 1.3-1.5 K. The cubic perovskite or filled Cu 3 Au structure is discussed as a type which is very unfavorable for the occurrence of superconductivity. (Auth.)

Structure of the novel ternary hydrides Li4Tt2D (Tt=Si and Ge)

International Nuclear Information System (INIS)

Wu Hui; Rush, J.J.; Maryland Univ., College Park, MD; Hartman, M.R.; Oregon State Univ., Corvallis, OR; Udovic, T.J.; Zhou Wei; Pennsylvania Univ., Philadelphia, PA; Bowman, R.C. Jr.; Vajo, J.J.

2007-01-01

The crystal structures of newly discovered Li 4 Ge 2 D and Li 4 Si 2 D ternary phases were solved by direct methods using neutron powder diffraction data. Both structures can be described using a Cmmm orthorhombic cell with all hydrogen atoms occupying Li 6 -octahedral interstices. The overall crystal structure and the geometry of these interstices are compared with those of other related phases, and the stabilization of this novel class of ternary hydrides is discussed. (orig.)

Thermotropic liquid crystals recent advances

CERN Document Server

Ramamoorthy, Ayyalusamy

2007-01-01

This book covers developments in the field of thermotropic liquid crystals and their functional importance. It also presents advances related to different sub-areas pertinent to this interdisciplinary area of research. This text brings together research from synthetic scientists and spectroscopists and attempts to bridge the gaps between these areas. New physical techniques that are powerful in characterizing these materials are discussed.

Synthesis of carbonated hydroxyapatite nanorods in liquid crystals

Directory of Open Access Journals (Sweden)

Daniella Dias Palombino de Campos

2009-09-01

Full Text Available Syntheses of calcium phosphate nanoparticles, carried out in systems formed from surfactant, oil and water, have resulted in materials with promising possibilities for application. The calcium phosphate particles were synthesized using two different liquid crystals, formed from RenexTM, cyclohexane and a salts solution. The morphology of the nanoparticles synthesized in the liquid crystals is similar to that of hydroxyapatite particles that form bone mineral, where collagen fibers connect these particles so as to form a composite. Therefore, the synthesis of calcium phosphate nanoparticles in the systems used in this work can advance current understanding of mineralization processes that result in the formation of bone mineral.

Liquid Crystal Airborne Display

Science.gov (United States)

1977-08-01

Cum.nings, J. P., et al., Properties and Limitations oe Liquid Crystals for Aircraft Displays, Honeywell Corporate Researc ."I Center, Final Report HR-72...basic module could be used to build displays for both the commercial and military! 157- marhecs, and so would establi sh a broad and sizable market ... market for the display becomes a reality; therein lies, f TABLE 16 THE COURSE OF FUTURE DISPLAY DEVELOPMENT Today 1976-77 1980 1985 Display Size 2" 1 3.2

The finite-size effect in thin liquid crystal systems

Science.gov (United States)

Śliwa, I.

2018-05-01

Effects of surface ordering in liquid crystal systems confined between cell plates are of great theoretical and experimental interest. Liquid crystals introduced in thin cells are known to be strongly stabilized and ordered by cell plates. We introduce a new theoretical method for analyzing the effect of surfaces on local molecular ordering in thin liquid crystal systems with planar geometry of the smectic layers. Our results show that, due to the interplay between pair long-range intermolecular forces and nonlocal, relatively short-range, surface interactions, both orientational and translational orders of liquid crystal molecules across confining cells are very complex. In particular, it is demonstrated that the SmA, nematic, and isotropic phases can coexist. The phase transitions from SmA to nematic, as well as from nematic to isotropic phases, occur not simultaneously in the whole volume of the system but begin to appear locally in some regions of the LC sample. Phase transition temperatures are demonstrated to be strongly affected by the thickness of the LC system. The dependence of the corresponding shifts of phase transition temperatures on the layer number is shown to exhibit a power law character. This new type of scaling behavior is concerned with the coexistence of local phases in finite systems. The influence of a specific character of interactions of molecules with surfaces and other molecules on values of the resulting critical exponents is also analyzed.

Chiral-nematic liquid crystals as one dimensional photonic materials in optical sensors

NARCIS (Netherlands)

Mulder, D.J.; Schenning, A.P.H.J.; Bastiaansen, C.W.M.

2014-01-01

Current developments in the field of thermotropic chiral-nematic liquid crystals as sensors are discussed. These one dimensional photonic materials are based on low molecular weight liquid crystals and chiral-nematic polymeric networks. For both low molecular weight LCs and polymer networks,

Thermal tunability of photonic bandgaps in liquid crystal infiltrated microstructured polymer optical fibers

DEFF Research Database (Denmark)

Yuan, Scott Wu; Wei, Lei; Alkeskjold, Thomas Tanggaard

2009-01-01

We demonstrate the photonic bandgap effect and the thermal tunability of bandgaps in microstructured polymer optical fibers infiltrated with liquid crystal. Two liquid crystals with opposite sign of the temperature gradient of the ordinary refractive index (E7 and MDA-00- 1444) are used to demons......We demonstrate the photonic bandgap effect and the thermal tunability of bandgaps in microstructured polymer optical fibers infiltrated with liquid crystal. Two liquid crystals with opposite sign of the temperature gradient of the ordinary refractive index (E7 and MDA-00- 1444) are used...... to demonstrate that both signs of the thermal tunability of the bandgaps are possible. The useful bandgaps are ultimately bounded to the visible range by the transparency window of the polymer....

Thermal Analysis, Mechanical and Rheological Behaviour of Melt Manufactured Polyethylene/Liquid Crystal Polymer Blends

Directory of Open Access Journals (Sweden)

Ilze ELKSNITE

2011-07-01

Full Text Available Modification of properties of conventional thermoplastics with thermotropic liquid crystal polymers, from one hand, allows decrease their viscosities, substantially facilitating processing conditions, and, from another hand, allows increase their exploitation properties. Orientation of the labile structure of liquid crystal polymer in extrusion or injection moulding causes specific reinforcement (so-called self-reinforcement to occur in the blends containing liquid crystal polymer. Up to now the effect of self-reinforcement is mostly investigated in the blends, containing considerable amount of liquid crystal polymer. In this research the effect of minor amounts of liquid crystalline co-polyester modifier on the properties of polyethylene is investigated. Various compositions of laboratory synthesized hydroxybenzoic acid /polyethylene terephtalate copolymer containing polyethylene composites have been manufactured by thermoplastic blending. It has been observed that 1 modulus of elasticity, yield strength and ultimate strength increase with raising the content of liquid crystalline modifier; 2 void content in the investigated polyethylene/liquid crystal copolymer composites is not greater that 1 %; 3 addition of liquid crystalline co-polyester modifier improves arrangement of PE crystalline phase.http://dx.doi.org/10.5755/j01.ms.17.2.483

Shrink, twist, ripple and melt: Studies of frustrated liquid crystals

Science.gov (United States)

Fernsler, Jonathan G.

Complex structures can arise out of a simple system with more than one competing influence on its behavior. The protypical example of this is the two-dimensional triangular lattice Ising model. The ferromagnetic model has two simple degenerate ground states of all spins up or down, but the antiferromagnetic model is a frustrated system. Its geometry does not allow satisfaction of the antiferro condition everywhere, which produces complex ordered structures with dimerization of the spins [1]. Without frustration, the complex structures and phase behavior are lost. All of the topics discussed in this thesis concern smectic liquid crystals. Liquid crystals are perhaps uniquely adept at manifesting frustrated phases. Their combination of periodicity in one or more dimensions allows ordered structures, yet their fluid nature in remaining dimensions allows creation of defects and extraordinarily complex structures in ways that a normal crystal could not tolerate. Liquid crystals contain a huge menagerie of frustrated phases and effects including the polarization modulated [2], vortex lattice [3], twist grain boundary [4], and blue [5] phases, as well as frustrated structures such as cholesteric or SmC* helix unwinding [6], defect lattices in thin films [7], and bend melted grain boundary defects [8], arising from boundary conditions and field effects. In this thesis, we study four liquid crystal systems that show unusual phase behavior or complex structures, deriving from the effects of frustration. Frustration, despite some human prejudices against the word, leaves nature all the more interesting and beautiful.

A Microwave Tunable Bandpass Filter for Liquid Crystal Applications

Science.gov (United States)

Cao, Weiping; Jiang, Di; Liu, Yupeng; Yang, Yuanwang; Gan, Baichuan

2017-07-01

In this paper, a novel microwave continuously tunable band-pass filter, based on nematic liquid crystals (LCs), is proposed. It uses liquid crystal (LC) as the electro-optic material to mainly realize frequency shift at microwave band by changing the dielectric anisotropy, when applying the bias voltage. According to simulation results, it achieves 840 MHz offset. Comparing to the existing tunable filter, it has many advantages, such as continuously tunable, miniaturization, low processing costs, low tuning voltage, etc. Thus, it has shown great potentials in frequency domain and practical applications in modern communication.

Flexoelectricity in an oxadiazole bent-core nematic liquid crystal

OpenAIRE

Kaur, Sarabjot; Panov, V. P.; Greco, C.; Ferrarini, A.; Görtz, Verena; Goodby, John W.; Gleeson, Helen F.

2014-01-01

We have determined experimentally the magnitude of the difference in the splay and bend flexoelectric coefficients, |e 1 − e 3|, of an oxadiazole bent-core liquid crystal by measuring the critical voltage for the formation of flexodomains together with their wave number. The coefficient |e 1 − e 3| is found to be a factor of 2–3 times higher than in most conventional calamitic nematic liquid crystals, varying from 8 pCm−1 to 20 pCm−1 across the ∼60 K—wide nematic regime. We have also calculat...

Cholesteric colloidal liquid crystals from phytosterol rod-like particles

NARCIS (Netherlands)

Rossi, L.; Sacanna, S.; Velikov, K.P.

2011-01-01

We report the first observation of chiral colloidal liquid crystals of rod-like particles from a low molecular weight organic compound— phytosterols. Based on the particles shape and crystal structure, we attribute this phenomenon to chiral distribution of surface charge on the surface of

Reorientation of single-wall carbon nanotubes in negative anisotropy liquid crystals by an electric field

Directory of Open Access Journals (Sweden)

Amanda García-García

2016-06-01

Full Text Available Single-wall carbon nanotubes (SWCNT are anisotropic nanoparticles that can cause modifications in the electrical and electro-optical properties of liquid crystals. The control of the SWCNT concentration, distribution and reorientation in such self-organized fluids allows for the possibility of tuning the liquid crystal properties. The alignment and reorientation of CNTs are studied in a system where the liquid crystal orientation effect has been isolated. Complementary studies including Raman spectroscopy, microscopic inspection and impedance studies were carried out. The results reveal an ordered reorientation of the CNTs induced by an electric field, which does not alter the orientation of the liquid crystal molecules. Moreover, impedance spectroscopy suggests a nonnegligible anchoring force between the CNTs and the liquid crystal molecules.

Phase-Shifting Liquid Crystal Interferometers for Microgravity Fluid Physics

Science.gov (United States)

Griffin, DeVon W.; Marshall, Keneth L.

2002-01-01

The initial focus of this project was to eliminate both of these problems in the Liquid Crystal Point-Diffraction Interferometer (LCPDI). Progress toward that goal will be described, along with the demonstration of a phase shifting Liquid Crystal Shearing Interferometer (LCSI) that was developed as part of this work. The latest LCPDI, other than a lens to focus the light from a test section onto a diffracting microsphere within the interferometer and a collimated laser for illumination, the pink region contained within the glass plates on the rod-mounted platform is the complete interferometer. The total width is approximately 1.5 inches with 0.25 inches on each side for bonding the electrical leads. It is 1 inch high and there are only four diffracting microspheres within the interferometer. As a result, it is very easy to align, achieving the first goal. The liquid crystal electro-optical response time is a function of layer thickness, with thinner devices switching faster due to a reduction in long-range viscoelastic forces between the LC molecules. The LCPDI has a liquid crystal layer thickness of 10 microns, which is controlled by plastic or glass microspheres embedded in epoxy 'pads' at the corners of the device. The diffracting spheres are composed of polystyrene/divinyl benzene polymer with an initial diameter of 15 microns. The spheres deform slightly when the interferometer is assembled to conform to the spacing produced by the microsphere-filled epoxy spacer pads. While the speed of this interferometer has not yet been tested, previous LCPDIs fabricated at the Laboratory for Laser Energetics switched at a rate of approximately 3.3 Hz, a factor of 10 slower than desired. We anticipate better performance when the speed of these interferometers is tested since they are approximately three times thinner. Phase shifting in these devices is a function of the AC voltage level applied to the liquid crystal. As the voltage increases, the dye in the liquid crystal

Sharp Morphological Transitions from Nanoscale Mixed-Anchoring Patterns in Confined Nematic Liquid Crystals

Energy Technology Data Exchange (ETDEWEB)

Armas-Pérez, Julio C. [Institute; División; Li, Xiao [Institute; Martínez-González, José A. [Institute; Smith, Coleman [Institute; Hernández-Ortiz, J. P. [Departamento; Nealey, Paul F. [Institute; Materials; de Pablo, Juan J. [Institute; Materials

2017-08-17

Liquid crystals are known to be particularly sensitive to orientational cues provided at surfaces or interfaces. In this work, we explore theoretically, computationally, and experimentally the behavior of liquid crystals on isolated nanoscale patterns with controlled anchoring characteristics at small length scales. The orientation of the liquid crystal is controlled through the use of chemically patterned polymer brushes that are tethered to a surface. This system can be engineered with remarkable precision, and the central question addressed here is whether a characteristic length scale exists at which information encoded on a surface is no longer registered by a liquid crystal. To do so, we adopt a tensorial description of the free energy of the hybrid liquidcrystal surface system, and we investigate its morphology in a systematic manner. For long and narrow surface stripes, it is found that the liquid crystal follows the instructions provided by the pattern down to 100 nm widths. This is accomplished through the creation of line defects that travel along the sides of the stripes. We show that a "sharp" morphological transition occurs from a uniform undistorted alignment to a dual uniform/splay-bend morphology. The theoretical and numerical predictions advanced here are confirmed by experimental observations. Our combined analysis suggests that nanoscale patterns can be used to manipulate the orientation of liquid crystals at a fraction of the energetic cost that is involved in traditional liquid crystal-based devices. The insights presented in this work have the potential to provide a new fabrication platform to assemble low power bistable devices, which could be reconfigured upon application of small external fields.

Mixing effects in the crystallization of supercooled quantum binary liquids

International Nuclear Information System (INIS)

Kühnel, M.; Kalinin, A.; Fernández, J. M.; Tejeda, G.; Moreno, E.; Montero, S.; Tramonto, F.; Galli, D. E.; Nava, M.; Grisenti, R. E.

2015-01-01

By means of Raman spectroscopy of liquid microjets, we have investigated the crystallization process of supercooled quantum liquid mixtures composed of parahydrogen (pH 2 ) or orthodeuterium (oD 2 ) diluted with small amounts of neon. We show that the introduction of the Ne impurities affects the crystallization kinetics in terms of a significant reduction of the measured pH 2 and oD 2 crystal growth rates, similarly to what found in our previous work on supercooled pH 2 -oD 2 liquid mixtures [Kühnel et al., Phys. Rev. B 89, 180201(R) (2014)]. Our experimental results, in combination with path-integral simulations of the supercooled liquid mixtures, suggest in particular a correlation between the measured growth rates and the ratio of the effective particle sizes originating from quantum delocalization effects. We further show that the crystalline structure of the mixtures is also affected to a large extent by the presence of the Ne impurities, which likely initiate the freezing process through the formation of Ne-rich crystallites

Mixing effects in the crystallization of supercooled quantum binary liquids

Energy Technology Data Exchange (ETDEWEB)

Kühnel, M.; Kalinin, A. [Institut für Kernphysik, J. W. Goethe-Universität, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Fernández, J. M.; Tejeda, G.; Moreno, E.; Montero, S. [Laboratory of Molecular Fluid Dynamics, Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006 Madrid (Spain); Tramonto, F.; Galli, D. E. [Laboratorio di Calcolo Parallelo e di Simulazioni di Materia Condensata, Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); Nava, M. [Laboratorio di Calcolo Parallelo e di Simulazioni di Materia Condensata, Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); Computational Science, Department of Chemistry and Applied Biosciences, ETH Zurich, USI Campus, Via Giuseppe Buffi 13, CH-6900 Lugano (Switzerland); Grisenti, R. E. [Institut für Kernphysik, J. W. Goethe-Universität, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); GSI - Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany)

2015-08-14

By means of Raman spectroscopy of liquid microjets, we have investigated the crystallization process of supercooled quantum liquid mixtures composed of parahydrogen (pH{sub 2}) or orthodeuterium (oD{sub 2}) diluted with small amounts of neon. We show that the introduction of the Ne impurities affects the crystallization kinetics in terms of a significant reduction of the measured pH{sub 2} and oD{sub 2} crystal growth rates, similarly to what found in our previous work on supercooled pH{sub 2}-oD{sub 2} liquid mixtures [Kühnel et al., Phys. Rev. B 89, 180201(R) (2014)]. Our experimental results, in combination with path-integral simulations of the supercooled liquid mixtures, suggest in particular a correlation between the measured growth rates and the ratio of the effective particle sizes originating from quantum delocalization effects. We further show that the crystalline structure of the mixtures is also affected to a large extent by the presence of the Ne impurities, which likely initiate the freezing process through the formation of Ne-rich crystallites.

Liquid Crystal Phases of Colloidal Platelets and their Use as Nanocomposite Templates

NARCIS (Netherlands)

Mourad, M.C.D.|info:eu-repo/dai/nl/304837563

2009-01-01

This thesis explores the gelation and liquid crystal phase behavior of colloidal dispersions of platelike particles as well as the use of such dispersions for the generation of nanocomposites. We report on the sol-gel, sol-glass and liquid crystal phase transitions of positively charged colloidal

Vapor-Liquid Equilibria in the Binary and Ternary Systems Composed of 2-Methylpentane, 3-Methyl-2-Butanone and 3-Methyl-2-Butanol

Czech Academy of Sciences Publication Activity Database

Psutka, Štěpán; Wichterle, Ivan

2005-01-01

Roč. 50, č. 4 (2005), s. 1338-1342 ISSN 0021-9568 R&D Projects: GA ČR(CZ) GA104/03/1555; GA AV ČR(CZ) KSK4040110 Institutional research plan: CEZ:AV0Z40720504 Keywords : vapor-liquid equilibrium * binary- ternary systems * isothermal Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.610, year: 2005

Kinetic study of lithium-cadmium ternary amalgam decomposition

International Nuclear Information System (INIS)

Cordova, M.H.; Andrade, C.E.

1992-01-01

The effect of metals, which form stable lithium phase in binary alloys, on the formation of intermetallic species in ternary amalgams and their effect on thermal decomposition in contact with water is analyzed. Cd is selected as ternary metal, based on general experimental selection criteria. Cd (Hg) binary amalgams are prepared by direct contact Cd-Hg, whereas Li is formed by electrolysis of Li OH aq using a liquid Cd (Hg) cathodic well. The decomposition kinetic of Li C(Hg) in contact with 0.6 M Li OH is studied in function of ageing and temperature, and these results are compared with the binary amalgam Li (Hg) decomposition. The decomposition rate is constant during one hour for binary and ternary systems. Ageing does not affect the binary systems but increases the decomposition activation energy of ternary systems. A reaction mechanism that considers an intermetallic specie participating in the activated complex is proposed and a kinetic law is suggested. (author)

Magneto-optic dynamics in a ferromagnetic nematic liquid crystal

Science.gov (United States)

Potisk, Tilen; Mertelj, Alenka; Sebastián, Nerea; Osterman, Natan; Lisjak, Darja; Brand, Helmut R.; Pleiner, Harald; Svenšek, Daniel

2018-01-01

We investigate dynamic magneto-optic effects in a ferromagnetic nematic liquid crystal experimentally and theoretically. Experimentally we measure the magnetization and the phase difference of the transmitted light when an external magnetic field is applied. As a model we study the coupled dynamics of the magnetization, M , and the director field, n , associated with the liquid crystalline orientational order. We demonstrate that the experimentally studied macroscopic dynamic behavior reveals the importance of a dynamic cross-coupling between M and n . The experimental data are used to extract the value of the dissipative cross-coupling coefficient. We also make concrete predictions about how reversible cross-coupling terms between the magnetization and the director could be detected experimentally by measurements of the transmitted light intensity as well as by analyzing the azimuthal angle of the magnetization and the director out of the plane spanned by the anchoring axis and the external magnetic field. We derive the eigenmodes of the coupled system and study their relaxation rates. We show that in the usual experimental setup used for measuring the relaxation rates of the splay-bend or twist-bend eigenmodes of a nematic liquid crystal one expects for a ferromagnetic nematic liquid crystal a mixture of at least two eigenmodes.

NATO Advanced Research Workshop on Incommensurate Crystals, Liquid Crystals, and Quasi-Crystals

CERN Document Server

Clark, N

1988-01-01

In this NATO-sponsored Advanced Research Workshop we succeeded in bringing together approximately forty scientists working in the three main areas of structurally incommensurate materials: incommensurate crystals (primarily ferroelectric insulators), incommensurate liquid crystals, and metallic quasi-crystals. Although these three classes of materials are quite distinct, the commonality of the physics of the origin and descrip­ tion of these incommensurate structures is striking and evident in these proceedings. A measure of the success of this conference was the degree to which interaction among the three subgroups occurred; this was facili­ tated by approximately equal amounts of theory and experiment in the papers presented. We thank the University of Colorado for providing pleasant housing and conference facilities at a modest cost, and we are especially grate­ ful to Ann Underwood, who retyped all the manuscripts into camera-ready form. J. F. Scott Boulder, Colorado N. A. Clark v CONTENTS PART I: INCO...

High-speed imaging polarimetry using liquid crystal modulators

Directory of Open Access Journals (Sweden)

Ambs P.

2010-06-01

Full Text Available This paper deals with dynamic polarimetric imaging techniques. The basics of modern polarimetry have been known for one and a half century, but no practical high-speed implementation providing the full polarization information is currently available. Various methods are reviewed which prove to be a trade-off between the complexity of the optical set-up and the amount of polarimetric information they provide (ie the number of components of the Stokes vector. Techniques using liquid crystal devices, incepted in the late 1990's, are emphasized. Optical set-ups we implemented are presented. We particularly focus on high-speed techniques (i.e. faster than 200 Hz using ferroelectric liquid crystal devices.

Soft Elasticity in Main Chain Liquid Crystal Elastomers

Directory of Open Access Journals (Sweden)

Anselm C. Griffin

2013-06-01

Full Text Available Main chain liquid crystal elastomers exhibit several interesting phenomena, such as three different regimes of elastic response, unconventional stress-strain relationship in one of these regimes, and the shape memory effect. Investigations are beginning to reveal relationships between their macroscopic behavior and the nature of domain structure, microscopic smectic phase structure, relaxation mechanism, and sample history. These aspects of liquid crystal elastomers are briefly reviewed followed by a summary of the results of recent elastic and high-resolution X-ray diffraction studies of the shape memory effect and the dynamics of the formation of the smectic-C chevron-like layer structure. A possible route to realizing auxetic effect at molecular level is also discussed.

Dye-Induced Enhancement of Optical Nonlinearity in Liquids and Liquid Crystals

International Nuclear Information System (INIS)

Muenster, R.; Jarasch, M.; Zhuang, X.; Shen, Y.

1997-01-01

Optical nonlinearity of liquid crystals (LC) in the isotropic phase can be enhanced by 1 order of magnitude by dissolving 0.1% of anthraquinone dye in the LC. The enhancement decreases by ∼30% when the LC transforms into the nematic phase. The same guest-host effect also exists in non-LC liquids. It can be explained by a model based on the change of guest-host interaction induced by optical excitations of the dye. copyright 1996 The American Physical Society

Liquid Crystals of Lithium Dodecylbenzenesulfonate for Electric Double Layer Capacitors

International Nuclear Information System (INIS)

Kuzmin, Andrey Vasil’evich; Yurtov, Evgeny V.

2016-01-01

Ionic lyotropic liquid crystals based on lithium dodecylbenzenesulfonate were used as electrolytes for electric double layer capacitors with carbon fibrous electrodes. The capacitors were tasted by cyclic voltammetry, galvanostatic charge and discharge, and impedance spectroscopy. The highest specific capacitance was achieved for electrical double layer capacitor equipped with ionic lyotropic liquid crystal of lithium dodecylbenzenesulfonate 35 wt% in water. The specific capacitance of capacitor was calculated from galvanostatic discharge curves – 15 F/g of carbon fibrous material

Smart lighting using a liquid crystal modulator

Science.gov (United States)

Baril, Alexandre; Thibault, Simon; Galstian, Tigran

2017-08-01

Now that LEDs have massively invaded the illumination market, a clear trend has emerged for more efficient and targeted lighting. The project described here is at the leading edge of the trend and aims at developing an evaluation board to test smart lighting applications. This is made possible thanks to a new liquid crystal light modulator recently developed for broadening LED light beams. The modulator is controlled by electrical signals and is characterized by a linear working zone. This feature allows the implementation of a closed loop control with a sensor feedback. This project shows that the use of computer vision is a promising opportunity for cheap closed loop control. The developed evaluation board integrates the liquid crystal modulator, a webcam, a LED light source and all the required electronics to implement a closed loop control with a computer vision algorithm.

Conductive properties of switchable photoluminescence thermosetting systems based on liquid crystals.

Science.gov (United States)

Tercjak, Agnieszka; Gutierrez, Junkal; Ocando, Connie; Mondragon, Iñaki

2010-03-16

Conductive properties of different thermosetting materials modified with nematic 4'-(hexyl)-4-biphenyl-carbonitrile (HBC) liquid crystal and rutile TiO(2) nanoparticles were successfully studied by means of tunneling atomic force miscroscopy (TUNA). Taking into account the liquid crystal state of the HBC at room temperature, depending on both the HBC content and the presence of TiO(2) nanoparticles, designed materials showed different TUNA currents passed through the sample. The addition of TiO(2) nanoparticles into the systems multiply the detected current if compared to the thermosetting systems without TiO(2) nanoparticles and simultaneously stabilized the current passed through the sample, making the process reversible since the absolute current values were almost the same applying both negative and positive voltage. Moreover, thermosetting systems modified with liquid crystals with and without TiO(2) nanoparticles are photoluminescence switchable materials as a function of temperature gradient during repeatable heating/cooling cycle. Conductive properties of switchable photoluminescence thermosetting systems based on liquid crystals can allow them to find potential application in the field of photoresponsive devices, with a high contrast ratio between transparent and opaque states.

Characterising laser beams with liquid crystal displays

CSIR Research Space (South Africa)

Dudley, Angela L

2016-09-01

Full Text Available the intensity, phase, wavefront, Poynting vector, and orbital angular momentum density of unknown optical fields. This measurement technique makes use of a single spatial light modulator (liquid crystal display), a Fourier transforming lens and detector (CCD...

Optimization and application of homogeneous liquid-liquid extraction in preconcentration of copper (II) in a ternary solvent system

Energy Technology Data Exchange (ETDEWEB)

Farajzadeh, Mir Ali [Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of)], E-mail: farajzade@yahoo.com; Bahram, Morteza [Department of Chemistry, Faculty of Science, Urmia University, Urmia (Iran, Islamic Republic of); Zorita, Saioa [Department of Analytical Chemistry, University of Lund, P.O. Box 124, 221 00 Lund (Sweden); Mehr, Behzad Ghorbani [Department of Chemistry, Faculty of Science, Urmia University, Urmia (Iran, Islamic Republic of)

2009-01-30

In this study a homogeneous liquid-liquid extraction based on the Ph-dependent phase-separation process was investigated using a ternary solvent system (water-acetic acid-chloroform) for the preconcentration of Cu{sup 2+} ions. 8-Hydroxy quinoline was used as the chelating agent prior to its extraction. Flame atomic absorption spectrophotometry using acetylene-air flame was used for the quantitation of analyte after preconcentration. The effect of various experimental parameters in extraction step was investigated using two optimization methods, one variable at a time and central composite design. The experimental design was done at five levels of operating parameters. Nearly the same optimized results were obtained using both methods: sample size, 5 mL; volume of NaOH 10 M, 2 mL; chloroform volume, 300 {mu}L; 8-hydroxy quinoline concentration more than 0.01 M and salt amount did not affect the extraction significantly. Under the optimum conditions the calibration graph was linear over the range 10-2000 {mu}g L{sup -1}. The relative standard deviation was 7.6% for six repeated determinations (C = 500 {mu}g L{sup -1}). Furthermore, the limit of detection (S/N = 3) and limit of quantification (S/N = 10) of the method were obtained as 1.74 and 6 {mu}g L{sup -1}, respectively.

Experimental investigation of phase equilibria in the Cu–Ni–Si ternary system

Energy Technology Data Exchange (ETDEWEB)

Liu, Xingjun; Xiang, Shulin; Yang, Shuiyuan; Shi, Rongpei; Wang, Cuiping, E-mail: wangcp@xmu.edu.cn

2013-11-25

Highlights: •Three isothermal sections of the Cu–Ni–Si system have been investigated. •The ternary compound τ{sub 1} and the liquid phase are confirmed at 1073 K. •The γ (Cu{sub 5}Si) and θ (Ni{sub 2}Si) phases can be stabilized at higher or lower temperatures. -- Abstract: The phase equilibria in the Cu–Ni–Si ternary system have been investigated experimentally by means of electron probe microanalysis (EPMA), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis on equilibrated ternary alloys. Three isothermal sections at 1073, 1173 and 1273 K are determined in the whole composition range. The existence of liquid phase and the ternary compound τ{sub 1} is confirmed at 1073 K. The binary γ (Cu{sub 5}Si), γ (Ni{sub 31}Si{sub 12}), δ (Ni{sub 2}Si) and θ (Ni{sub 2}Si) phases exhibit a considerable solubility of a third element. In addition, the γ (Cu{sub 5}Si) and θ (Ni{sub 2}Si) phases can be stabilized by the addition of Ni and Cu, respectively.

Dielectric relaxation studies in 5CB nematic liquid crystal at 9 GHz ...

Indian Academy of Sciences (India)

Resonance width, shift in resonance frequency, relaxation time and activation energy of 5CB nematic liquid crystal are measured using microwave cavity technique under the influence of an external magnetic field at 9 GHz and at different temperatures. The dielectric response in liquid crystal at different temperatures and ...

Nonlinear dynamical phenomena in liquid crystals

International Nuclear Information System (INIS)

Wang, X.Y.; Sun, Z.M.

1988-09-01

Because of the existence of the orientational order and anisotropy in liquid crystals, strong nonlinear phenomena and singular behaviors, such as solitary wave, transient periodic structure, chaos, fractal and viscous fingering, can be excited by a very small disturbance. These phenomena and behaviors are in connection with physics, biology and mathematics. 12 refs, 6 figs

Viscoelastic modes in chiral liquid crystals

Indian Academy of Sciences (India)

amit@fs.rri.local.net (Amit Kumar Agarwal)

our studies on the viscoelastic modes of some chiral liquid crystals using dynamic light scattering. We discuss viscoelastic ... In the vicinity of the direct beam for a sample aligned in the Bragg mode and. 297 ... experimental investigations on these modes. Duke and Du ..... scattering volume is not true in practice. In an actual ...

Multistability in planar liquid crystal wells

KAUST Repository

Luo, Chong

2012-06-08

A planar bistable liquid crystal device, reported in Tsakonas, is modeled within the Landau-de Gennes theory for nematic liquid crystals. This planar device consists of an array of square micrometer-sized wells. We obtain six different classes of equilibrium profiles and these profiles are classified as diagonal or rotated solutions. In the strong anchoring case, we propose a Dirichlet boundary condition that mimics the experimentally imposed tangent boundary conditions. In the weak anchoring case, we present a suitable surface energy and study the multiplicity of solutions as a function of the anchoring strength. We find that diagonal solutions exist for all values of the anchoring strength W≥0, while rotated solutions only exist for W≥W c>0, where W c is a critical anchoring strength that has been computed numerically. We propose a dynamic model for the switching mechanisms based on only dielectric effects. For sufficiently strong external electric fields, we numerically demonstrate diagonal-to-rotated and rotated-to-diagonal switching by allowing for variable anchoring strength across the domain boundary. © 2012 American Physical Society.

Multistability in planar liquid crystal wells

KAUST Repository

Luo, Chong; Majumdar, Apala; Erban, Radek

2012-01-01

A planar bistable liquid crystal device, reported in Tsakonas, is modeled within the Landau-de Gennes theory for nematic liquid crystals. This planar device consists of an array of square micrometer-sized wells. We obtain six different classes of equilibrium profiles and these profiles are classified as diagonal or rotated solutions. In the strong anchoring case, we propose a Dirichlet boundary condition that mimics the experimentally imposed tangent boundary conditions. In the weak anchoring case, we present a suitable surface energy and study the multiplicity of solutions as a function of the anchoring strength. We find that diagonal solutions exist for all values of the anchoring strength W≥0, while rotated solutions only exist for W≥W c>0, where W c is a critical anchoring strength that has been computed numerically. We propose a dynamic model for the switching mechanisms based on only dielectric effects. For sufficiently strong external electric fields, we numerically demonstrate diagonal-to-rotated and rotated-to-diagonal switching by allowing for variable anchoring strength across the domain boundary. © 2012 American Physical Society.

Liquid crystals with novel terminal chains as ferroelectric liquid crystal hosts

International Nuclear Information System (INIS)

Cosquer, G.Y.

2000-02-01

Changes to the molecular structure of liquid crystals can have a significant effect upon their mesomorphism and ferroelectric properties. Most of the research in liquid crystal for display applications concentrates on the design and synthesis of novel mesogenic cores to which straight terminal alkyl or alkoxy chains are attached. However, little is known about the effects upon the mesomorphism and ferroelectric properties of varying the terminal chains. The compounds prepared in this work have a common core - a 2,3-difluoroterphenyl unit with a nine-atom alkyl (nonyl) or alkoxy (octyloxy) chain at the 4-position, but with an unusual chain at the 4''-position. In some cases the terminal chain contains hetero atoms such as silicon, oxygen, chlorine and bromine or has a bulky end group. In total 46 final materials were synthesised in an attempt to understand the effect of an unusual terminal chains on mesomorphism and for some of these compounds the effect upon the switching times when added to a standard ferroelectric mixture were investigated. It was found that most compounds containing a bulky end group only displayed a smectic C phase, compounds with a halogen substituent as an end unit displayed a smectic A phase and that increasing the chain flexibility by introducing an oxygen atom in the chain reduces the melting and clearing points. The electro-optical measurements carried out on ferroelectric mixtures containing a bulky end group compound showed that shorter switching times were produced than for the ferroelectric mixture containing a straight chain compound. It is suggested that a bulky end group diminishes te extent of interlayer mixing in the chiral smectic C phase and therefore the molecules move more easily with ferroelectric switching. (author)

Directional Scattering of Semiconductor Nanoparticles Embedded in a Liquid Crystal

Directory of Open Access Journals (Sweden)

Braulio García-Cámara

2014-04-01

Full Text Available Light scattering by semiconductor nanoparticles has been shown to be more complex than was believed until now. Both electric and magnetic responses emerge in the visible range. In addition, directional effects on light scattering of these nanoparticles were recently obtained. In particular, zero backward and minimum-forward scattering are observed. These phenomena are very interesting for several applications such as, for instance, optical switches or modulators. The strong dependence of these phenomena on the properties of both the particle and the surrounding medium can be used to tune them. The electrical control on the optical properties of liquid crystals could be used to control the directional effects of embedded semiconductor nanoparticles. In this work, we theoretically analyze the effects on the directional distribution of light scattering by these particles when the refractive index of a surrounded liquid crystal changes from the ordinary to the extraordinary configuration. Several semiconductor materials and liquid crystals are studied in order to optimize the contrast between the two states.

Liquid crystal templating as an approach to spatially and temporally organise soft matter.

Science.gov (United States)

van der Asdonk, Pim; Kouwer, Paul H J

2017-10-02

Chemistry quickly moves from a molecular science to a systems science. This requires spatial and temporal control over the organisation of molecules and molecular assemblies. Whilst Nature almost by default (transiently) organises her components at multiple different length scales, scientists struggle to realise even relatively straightforward patterns. In the past decades, supramolecular chemistry has taught us the rules to precisely engineer molecular assembly at the nanometre scale. At higher length scales, however, we are bound to top-down nanotechnology techniques to realise order. For soft, biological matter, many of these top-down techniques come with serious limitations since the molecules generally show low susceptibilities to the applied stimuli. A new method is based on liquid crystal templating. In this hierarchical approach, a liquid crystalline host serves as the scaffold to order polymers or assemblies. Being a liquid crystal, the host material can be ordered at many different length scales and on top of that, is highly susceptible to many external stimuli, which can even be used to manipulate the liquid crystal organisation in time. As a result, we anticipate large control over the organisation of the materials inside the liquid crystalline host. Recently, liquid crystal templating was also realised in water. This suddenly makes this tool highly applicable to start organising more delicate biological materials or even small organisms. We review the scope and limitations of liquid crystal templating and look out to where the technique may lead us.

Peculiarities of component interaction in {l_brace}Gd, Er{r_brace}-V-Sn Ternary systems at 870 K and crystal structure of RV{sub 6}Sn{sub 6} stannides

Energy Technology Data Exchange (ETDEWEB)

Romaka, L., E-mail: romakal@franko.lviv.ua [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya str. 6, 79005 Lviv (Ukraine); Stadnyk, Yu. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya str. 6, 79005 Lviv (Ukraine); Romaka, V.V. [Department of Materials Engineering and Applied Physics, Lviv Polytechnic National University, Ustyyanovycha Str. 5, 79013 Lviv (Ukraine); Demchenko, P.; Stadnyshyn, M.; Konyk, M. [Inorganic Chemistry Department, Ivan Franko Lviv National University, Kyryla and Mefodiya str. 6, 79005 Lviv (Ukraine)

2011-09-08

Highlights: > {l_brace}Gd, Er{r_brace}-V-Sn ternary systems at 870 K are characterized by formation of stannides with general compositions RV{sub 6}Sn{sub 6}. > Isostructural RV{sub 6}Sn{sub 6} compounds were also found with Y, Dy, Ho, Tm, and Lu. > The crystal structure of RV{sub 6}Sn{sub 6} compounds was determined by powder diffraction method. > Structural analysis showed that RV{sub 6}Sn{sub 6} compounds (R = Gd, Dy-Tm, Lu) are disordered; YV{sub 6}Sn{sub 6} is characterized by structure ordering. - Abstract: The phase equilibria in the Gd-V-Sn and Er-V-Sn ternary systems were studied at 870 K by means of X-ray and metallographic analyses in the whole concentration range. Both Gd-V-Sn and Er-V-Sn systems are characterized by formation of one ternary compound at investigated temperature, with stoichiometry RV{sub 6}Sn{sub 6} (SmMn{sub 6}Sn{sub 6}-type, space group P6/mmm, a = 0.55322(3) nm, c = 0.91949(7) nm for Gd, a = 0.55191(2) nm, c = 0.91869(8) nm for Er). Solubility of the third component in the binary compounds was not observed. Compounds with the SmMn{sub 6}Sn{sub 6}-type were also found with Dy, Ho, Tm, and Lu, while YV{sub 6}Sn{sub 6} compound crystallizes in HfFe{sub 6}Ge{sub 6} structure type. All investigated compounds are the first ternary stannides with rare earth elements and vanadium.

A microstructure-composition map of a ternary liquid/liquid/particle system with partially-wetting particles.

Science.gov (United States)

Yang, Junyi; Roell, David; Echavarria, Martin; Velankar, Sachin S

2017-11-22

We examine the effect of composition on the morphology of a ternary mixture comprising two molten polymeric liquid phases (polyisobutylene and polyethylene oxide) and micron-scale spherical silica particles. The silica particles were treated with silanes to make them partially wetted by both polymers. Particle loadings up to 30 vol% are examined while varying the fluid phase ratios across a wide range. Numerous effects of particle addition are catalogued, stabilization of Pickering emulsions and of interfacially-jammed co-continuous microstructures, meniscus-bridging of particles, particle-induced coalescence of the dispersed phase, and significant shifts in the phase inversion composition. Many of the effects are asymmetric, for example particle-induced coalescence is more severe and drop sizes are larger when polyisobutylene is the continuous phase, and particles promote phase continuity of the polyethylene oxide. These asymmetries are likely attributable to a slight preferential wettability of the particles towards the polyethylene oxide. A state map is constructed which classifies the various microstructures within a triangular composition diagram. Comparisons are made between this diagram vs. a previous one constructed for the case when particles are fully-wetted by polyethylene oxide.

Modeling texture transitions in cholesteric liquid crystal droplets

Science.gov (United States)

Selinger, Robin; Gimenez-Pinto, Vianney; Lu, Shin-Ying; Selinger, Jonathan; Konya, Andrew

2012-02-01

Cholesteric liquid crystals can be switched reversibly between planar and focal-conic textures, a property enabling their application in bistable displays, liquid crystal writing tablets, e-books, and color switching ``e-skins.'' To explore voltage-pulse induced switching in cholesteric droplets, we perform simulation studies of director dynamics in three dimensions. Electrostatics calculations are solved at each time step using an iterative relaxation method. We demonstrate that as expected, a low amplitude pulse drives the transition from planar to focal conic, while a high amplitude pulse drives the transition from focal conic back to the planar state. We use the model to explore the effects of droplet shape, aspect ratio, and anchoring conditions, with the goal of minimizing both response time and energy consumption.

Electrothermally Driven Fluorescence Switching by Liquid Crystal Elastomers Based On Dimensional Photonic Crystals.

Science.gov (United States)

Lin, Changxu; Jiang, Yin; Tao, Cheng-An; Yin, Xianpeng; Lan, Yue; Wang, Chen; Wang, Shiqiang; Liu, Xiangyang; Li, Guangtao

2017-04-05

In this article, the fabrication of an active organic-inorganic one-dimensional photonic crystal structure to offer electrothermal fluorescence switching is described. The film is obtained by spin-coating of liquid crystal elastomers (LCEs) and TiO 2 nanoparticles alternatively. By utilizing the property of LCEs that can change their size and shape reversibly under external thermal stimulations, the λ max of the photonic band gap of these films is tuned by voltage through electrothermal conversion. The shifted photonic band gap further changes the matching degree between the photonic band gap of the film and the emission spectrum of organic dye mounting on the film. With rhodamine B as an example, the enhancement factor of its fluorescence emission is controlled by varying the matching degree. Thus, the fluorescence intensity is actively switched by voltage applied on the system, in a fast, adjustable, and reversible manner. The control chain of using the electrothermal stimulus to adjust fluorescence intensity via controlling the photonic band gap is proved by a scanning electron microscope (SEM) and UV-vis reflectance. This mechanism also corresponded to the results from the finite-difference time-domain (FDTD) simulation. The comprehensive usage of photonic crystals and liquid crystal elastomers opened a new possibility for active optical devices.

Thermal diode made by nematic liquid crystal

Energy Technology Data Exchange (ETDEWEB)

Melo, Djair, E-mail: djfmelo@gmail.com [Instituto de Física, Universidade Federal de Alagoas, Av. Lourival Melo Mota, s/n, 57072-900 Maceió, AL (Brazil); Fernandes, Ivna [Instituto de Física, Universidade Federal de Alagoas, Av. Lourival Melo Mota, s/n, 57072-900 Maceió, AL (Brazil); Moraes, Fernando [Departamento de Física, CCEN, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-900, João Pessoa, PB (Brazil); Departamento de Física, Universidade Federal Rural de Pernambuco, 52171-900 Recife, PE (Brazil); Fumeron, Sébastien [Institut Jean Lamour, Université de Lorraine, BP 239, Boulevard des Aiguillettes, 54506 Vandoeuvre les Nancy (France); Pereira, Erms [Escola Politécnica de Pernambuco, Universidade de Pernambuco, Rua Benfíca, 455, Madalena, 50720-001 Recife, PE (Brazil)

2016-09-07

This work investigates how a thermal diode can be designed from a nematic liquid crystal confined inside a cylindrical capillary. In the case of homeotropic anchoring, a defect structure called escaped radial disclination arises. The asymmetry of such structure causes thermal rectification rates up to 3.5% at room temperature, comparable to thermal diodes made from carbon nanotubes. Sensitivity of the system with respect to the heat power supply, the geometry of the capillary tube and the molecular anchoring angle is also discussed. - Highlights: • An escaped radial disclination as a thermal diode made by a nematic liquid crystal. • Rectifying effects comparable to those caused by carbon and boron nitride nanotubes. • Thermal rectification increasing with radius and decreasing with height of the tube. • Asymmetric BCs cause rectification from the spatial asymmetry produced by the escape. • Symmetric BCs provide rectifications smaller than those yields by asymmetric BCs.

Photosensitive bent-core liquid crystals based on methyl substituted 3-hydroxybenzoic acid.

Czech Academy of Sciences Publication Activity Database

Kohout, M.; Alaasar, M.; Poryvai, A.; Novotná, Vladimíra; Poppe, S.; Tschierske, C.; Svoboda, J.

2017-01-01

Roč. 7, č. 57 (2017), s. 35805-35813 ISSN 2046-2069 R&D Projects: GA ČR GA16-12150S Institutional support: RVO:68378271 Keywords : liquid crystals * photosensitivity * bent-core liquid crystals * 3-hydroxybenzoic acid Subject RIV: JJ - Other Materials OBOR OECD: Nano-materials (production and properties) Impact factor: 3.108, year: 2016

Search for new ternary Al, Ga or In containing phases using information forecasting system

International Nuclear Information System (INIS)

Kiseleva, N.N.; Burkhanov, G.S.

1989-01-01

Automated system of search for regularities in the formation of crystal phases and forecasting of new compounds with required properties, comprising data base on the properties of ternary inorganic compounds and cybernetic forecasting system, has been developed. General principles of operation of the developed information-forecasting system are considered. Efficiency of the system operation is shown, using as an example the search for new ternary compounds with aluminium, gallium and indium, crystallized in ZrNiAl, TiNiSi, ThCr 2 Si 2 , CaAl 2 Si 2 structural types. Results of the above-mentioned phases forecasting are shown

Compact electrically controlled broadband liquid crystal photonic bandgap fiber polarizer

DEFF Research Database (Denmark)

Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard

2009-01-01

An electrically controlled liquid crystal photonic-bandgap fiber polarizer is experimentally demonstrated. A maximum 21.3dB electrically tunable polarization extinction ratio is achieved with 45° rotatable transmission axis as well as switched on and off in 1300nm–1600nm.......An electrically controlled liquid crystal photonic-bandgap fiber polarizer is experimentally demonstrated. A maximum 21.3dB electrically tunable polarization extinction ratio is achieved with 45° rotatable transmission axis as well as switched on and off in 1300nm–1600nm....

Use of thermodynamic calculation for investigating phase diagram of the ternary system NaCl-PbCl2-NdCl3

International Nuclear Information System (INIS)

Kostygov, V.I.; Potemin, S.S.

1984-01-01

Thermodynamic calculation of meltability diagram of ternary system NaCl-PbCl 2 -NdCl 3 with the use of literature and experimental data on meltability diagrams of binary systems forming it, as well as data on crystallization heats of the components, has been carried out. Equations are derived under condition of pseudoperfection of the ternary system. 64 mol.% PbCl 2 , 26 mol.% NaCl, 10 mol.% NdCl 3 and average temperature of crystallization 391 deg C correspond to the calculated composition of the ternary eutectics, 49 mol.% PbCl 2 , 35 mol.% NaCl, 16 mol.% NdCl 3 and average temperature of peritectic transformation 416 deg C - to the composition of the ternary peritectic. The results obtained agree well with the experimental data

Thermal conductivity of Glycerol's liquid, glass, and crystal states, glass-liquid-glass transition, and crystallization at high pressures.

Science.gov (United States)

Andersson, Ove; Johari, G P

2016-02-14

To investigate the effects of local density fluctuations on phonon propagation in a hydrogen bonded structure, we studied the thermal conductivity κ of the crystal, liquid, and glassy states of pure glycerol as a function of the temperature, T, and the pressure, p. We find that the following: (i) κcrystal is 3.6-times the κliquid value at 140 K at 0.1 MPa and 2.2-times at 290 K, and it varies with T according to 138 × T(-0.95); (ii) the ratio κliquid (p)/κliquid (0.1 MPa) is 1.45 GPa(-1) at 280 K, which, unexpectedly, is about the same as κcrystal (p)/κcrystal (0.1 MPa) of 1.42 GPa(-1) at 298 K; (iii) κglass is relatively insensitive to T but sensitive to the applied p (1.38 GPa(-1) at 150 K); (iv) κglass-T plots show an enhanced, pressure-dependent peak-like feature, which is due to the glass to liquid transition on heating; (v) continuous heating cold-crystallizes ultraviscous glycerol under pressure, at a higher T when p is high; and (vi) glycerol formed by cooling at a high p and then measured at a low p has a significantly higher κ than the glass formed by cooling at a low p. On heating at a fixed low p, its κ decreases before its glass-liquid transition range at that p is reached. We attribute this effect to thermally assisted loss of the configurational and vibrational instabilities of a glass formed at high p and recovered at low p, which is different from the usual glass-aging effect. While the heat capacity, entropy, and volume of glycerol crystal are less than those for its glass and liquid, κcrystal of glycerol, like its elastic modulus and refractive index, is higher. We discuss these findings in terms of the role of fluctuations in local density and structure, and the relations between κ and the thermodynamic quantities.

Synthesis and characterization of the ternary telluroargentate K4[Ag18Te11

KAUST Repository

Davaasuren, Bambar; Dashjav, Enkhtsetseg; Rothenberger, Alexander

2014-01-01

The ternary potassium telluroargentate(I), K4[Ag18Te11], was prepared by solvothermal synthesis in ethylenediamine at 160 °C. It crystallizes in the cubic space group Fm3¯ m (no. 225) with the cell parameter a = 18.6589(6) Å. The crystal structure

A flexible optically re-writable color liquid crystal display

Science.gov (United States)

Zhang, Yihong; Sun, Jiatong; Liu, Yang; Shang, Jianhua; Liu, Hao; Liu, Huashan; Gong, Xiaohui; Chigrinov, Vladimir; Kowk, Hoi Sing

2018-03-01

It is very difficult to make a liquid crystal display (LCD) that is flexible. However, for an optically re-writable LCD (ORWLCD), only the spacers and the substrates need to be flexible because the driving unit and the display unit are separate and there are no electronics in the display part of ORWLCD. In this paper, three flexible-spacer methods are proposed to achieve this goal. A cholesteric liquid crystal colored mirror with a polarizer behind it is used as the colored reflective backboard of an ORWLCD. Polyethersulfone substrates and flexible spacers are used to make the optically re-writable cell insensitive to mechanical force.

Uniform deposition of ternary chalcogenide nanoparticles onto mesoporous TiO{sub 2} film using liquid carbon dioxide-based coating

Energy Technology Data Exchange (ETDEWEB)

Nursanto, Eduardus Budi [Clean Energy Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136–791 (Korea, Republic of); Department of Clean Energy and Chemical Engineering, Korea University of Science and Technology,217, Gajeong-ro, Yuseong-gu, Daejeon 305–333 (Korea, Republic of); Park, Se Jin [Clean Energy Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136–791 (Korea, Republic of); Jeon, Hyo Sang; Hwang, Yun Jeong [Clean Energy Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136–791 (Korea, Republic of); Department of Clean Energy and Chemical Engineering, Korea University of Science and Technology,217, Gajeong-ro, Yuseong-gu, Daejeon 305–333 (Korea, Republic of); Kim, Jaehoon, E-mail: jaehoonkim@skku.edu [School of Mechanical Engineering, Sungkyunkwan University, 2066, Seobu-Ro, Jangan-Gu, Suwon, GyeongGi-Do 440–746 (Korea, Republic of); SKKU Advanced Institute of Nano Technology (SAINT), 2066, Seobu-Ro, Jangan-Gu, Suwon, GyeongGi-Do 440–746 (Korea, Republic of); Min, Byoung Koun, E-mail: bkmin@kist.re.kr [Clean Energy Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136–791 (Korea, Republic of); Department of Clean Energy and Chemical Engineering, Korea University of Science and Technology,217, Gajeong-ro, Yuseong-gu, Daejeon 305–333 (Korea, Republic of); Green School, Korea University, 145,Anam-ro, Seongbuk-gu, Seoul 136–713 (Korea, Republic of)

2014-08-28

We report the simultaneous deposition of two different metal precursors dissolved in liquid carbon dioxide (l-CO{sub 2}), aiming to the synthesis of ternary chalcopyrite (e.g. CuInS{sub 2}) nanoparticles on a mesoporous TiO{sub 2} film. The l-CO{sub 2}-based deposition of Cu and In precursors and subsequent reaction with a dilute H{sub 2}S gas resulted in Cu{sub x}In{sub y}S{sub z} nanoparticles uniformly deposited across the entire thickness of a mesoporous TiO{sub 2} film. Further heat treatment (air annealing and sulfurization) led to the formation of more stoichiometric CuInS{sub 2} nanoparticles. The formation of CuInS{sub 2} on TiO{sub 2} was confirmed by scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. The crystal growth of CuInS{sub 2} was also found to be controllable by adjusting the number of coating cycles of the l-CO{sub 2}-based deposition. - Highlights: • Simultaneous deposition of two different metal precursors dissolved in l-CO{sub 2}. • Uniform deposition of CuInS{sub 2} nanoparticles across mesoporous TiO{sub 2} film. • Highly crystalline CuInS{sub 2} formed on mesoporous TiO{sub 2} film. • Nearly stoichiometric ratio of Cu:In:S was obtained.

Experimental Investigation of Ternary Alloys for Fusion Breeding Blankets

Energy Technology Data Exchange (ETDEWEB)

Choi, B. William [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chiu, Ing L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-10-26

Future fusion power plants based on the deuterium-tritium (DT) fuel cycle will be required to breed the T fuel via neutron reactions with lithium, which will be incorporated in a breeding blanket that surrounds the fusion source. Recent work by LLNL proposed the used of liquid Li as the breeder in an inertial fusion energy (IFE) power plant. Subsequently, an LDRD was initiated to develop alternatives ternary alloy liquid metal breeders that have reduced chemical reactivity with water and air compared to pure Li. Part of the work plan was to experimentally investigate the phase diagrams of ternary alloys. Of particular interest was measurement of the melt temperature, which must be low enough to be compatible with the temperature limits of the steel used in the construction of the chamber and heat transfer system.

Experimental measurement and prediction of (liquid + liquid + liquid) equilibrium for the system (n-hexadecane + water + triacetin)

International Nuclear Information System (INIS)

Revellame, Emmanuel D.; Holmes, William E.; Hernandez, Rafael; French, W. Todd; Forks, Allison; Ashe, Taylor; Estévez, L. Antonio

2016-01-01

Highlights: • Phase diagram for the system n-hexadecane + water + triacetin was established at T = 296.15 K and atmospheric pressure (0.1 MPa). • Both NRTL and UNIQUAC activity coefficient model adequately predicts the LLLE of the ternary system. • The phase equilibrium of the system is predominantly dictated by enthalpic contributions to the activity coefficient. - Abstract: The phase diagram for the ternary system containing (n-hexadecane + water + triacetin) was obtained experimentally at T = 296.15 K and ambient pressure. Results show that this system is of Type 3 according to the Treybal classification of ternary system. NRTL and UNIQUAC interaction parameters were calculated from binary phase equilibrium values and were used to predict the (liquid + liquid + liquid) equilibrium (LLLE) region. Results indicated that both NRTL and UNIQUAC could predict the LLLE region of the system with similar precision as indicated by the comparable standard deviations. This indicates that the enthalpic contribution to the activity coefficient is predominant and entropic contributions can be neglected.

NMR and molecular dynamics of small solutes in liquid crystals

International Nuclear Information System (INIS)

Luyten, P.R.

1984-01-01

NMR relaxation measurements, using a wide variety of modern pulse techniques, can yield valuable information about molecular motions. In this thesis the applicability of theories developed to describe spin relaxation phenomena in partially ordered media is studied for small solutes in liquid crystals. 1 H, 2 H, 13 C and 14 N relaxation measurements are interpreted by means of a model, in which fast anisotropic re-orientational motion in an orienting potential combined with contributions from cooperative fluctuations in the surrounding liquid crystal molecules, induce the observed frequency dependent relaxation behavior. (orig.)

Microchannel-flowed-plasma modification of octadecyltrichlorosilane self-assembled-monolayers for liquid crystal alignment

International Nuclear Information System (INIS)

Zheng, W.; Chiang, C.-Y.; Underwood, I.

2013-01-01

We report that a chemical patterning technique based on local plasma modification of self-assembled monolayers has been utilized to fabricate surfaces for domain liquid crystal alignment. Highly hydrophobic octadecyltrichlorosilane monolayers deposited on glass substrates coated with Indium-Tin-Oxide were brought into contact with elastomeric stamps comprising trenches on a micro scale, and then exposed to an oxygen plasma. In the regions exposed to the plasma the monolayer was etched away leaving a patterned surface that exhibited surface energy differences between surface domains. The surfaces that bear the micropatterns have been shown to be capable of producing patterned alignment of nematic liquid crystal. - Highlights: • Chemical surface-patterning is used to fabricate liquid crystal alignment surface. • Highly hydrophobic octadecyltrichlorosilane monolayer is deposited on substrate. • O 2 plasma flow is used to etch the monolayer to form patterned surface. • The patterned surface exhibits surface energy differences between surface domains. • The surface borne the micropatterns is capable of domain liquid crystal alignment

Controlling the volatility of the written optical state in electrochromic DNA liquid crystals

Science.gov (United States)

Liu, Kai; Varghese, Justin; Gerasimov, Jennifer Y.; Polyakov, Alexey O.; Shuai, Min; Su, Juanjuan; Chen, Dong; Zajaczkowski, Wojciech; Marcozzi, Alessio; Pisula, Wojciech; Noheda, Beatriz; Palstra, Thomas T. M.; Clark, Noel A.; Herrmann, Andreas

2016-05-01

Liquid crystals are widely used in displays for portable electronic information display. To broaden their scope for other applications like smart windows and tags, new material properties such as polarizer-free operation and tunable memory of a written state become important. Here, we describe an anhydrous nanoDNA-surfactant thermotropic liquid crystal system, which exhibits distinctive electrically controlled optical absorption, and temperature-dependent memory. In the liquid crystal isotropic phase, electric field-induced colouration and bleaching have a switching time of seconds. Upon transition to the smectic liquid crystal phase, optical memory of the written state is observed for many hours without applied voltage. The reorientation of the DNA-surfactant lamellar layers plays an important role in preventing colour decay. Thereby, the volatility of optoelectronic state can be controlled simply by changing the phase of the material. This research may pave the way for developing a new generation of DNA-based, phase-modulated, photoelectronic devices.

Characteristics of bulk liquid undercooling and crystallization ...

Indian Academy of Sciences (India)

Characteristics of bulk liquid undercooling and crystallization behaviors ... cooling rate is fixed, the change of undercooling depends on the melt processing tem- ... solidification and a deep knowledge of undercooling of ... evolution, to obtain the information for the nucleation and ..... When cooling rate is fixed, the change.

Nuclear magnetic resonance of liquid crystals

National Research Council Canada - National Science Library

Dong, Ronald Y

1997-01-01

... operator in the small-step rotational diffusion model, while appendix D contains a list of liquid crystal abbreviations used in the book. A portion of this revision is carried out while the author is on leave at the University of Pisa. The author wishes to thank Professor C.A. Veracini for his kind hospitality and many authors for their preprints....

Color Gamut of a Nematic Liquid Crystal Display

Science.gov (United States)

Shimomura, Teruo; Mada, Hitoshi; Kobayashi, Shunsuke

1980-05-01

The theoretical color gamut of a nematic liquid crystal display is described. The color gamut of a tunable birefringence mode and a guest host mode are revealed with the CIE chromaticity diagram and color solid. In order to account for the quantitative color gamut, color matching between the given chromaticity coordinates and those calculated is investigated. Color matching is performed by a combination of three liquid crystal subcells (A, B, C), where each subcell receives the voltage VA, VB, VC or contains the dye amount a, b, c. Calculation of the value of voltage or dye amount was executed by the matrix representation method. The calculated data are in good agreement with the given data within 0.50 CIE-UNIT color difference in the 1964 CIE (U*, V*, W*) color scale.

Note: High-power piezoelectric transformer fabricated with ternary relaxor ferroelectric Pb(Mg(1/3)Nb(2/3))O3-Pb(In(1/2)Nb(1/2))O3-PbTiO3 single crystal.

Science.gov (United States)

Wang, Qing; Ma, Chuanguo; Wang, Feifei; Liu, Bao; Chen, Jianwei; Luo, Haosu; Wang, Tao; Shi, Wangzhou

2016-03-01

A plate-shaped piezoelectric transformer was designed and fabricated using ternary relaxor ferroelectric single crystal Pb(Mg(1/3)Nb(2/3))O3-Pb(In(1/2)Nb(1/2))O3-PbTiO3. Both the input and output sections utilized the transverse-extensional vibration mode. The frequency and load dependences of the electrical properties for the proposed transformer were systematically studied. Results indicated that under a matching load resistance of 14.9 kΩ, a maximum output power of 2.56 W was obtained with the temperature rise less than 5 °C. The corresponding power density reached up to 50 W/cm(3). This ternary single-crystal transformer had potential applications in compact-size converters requiring high power density.

A Polarization Maintaining Filter based on a Liquid-Crystal-Photonic-Bandgap-Fiber

DEFF Research Database (Denmark)

Scolari, Lara; Olausson, Christina Bjarnal Thulin; Turchinovich, Dmitry

2008-01-01

A polarization maintaining filter based on a liquid-crystal-photonic-bandgap-fiber is demonstrated. Its polarization extinction ratio is 14 dB at 1550 nm. Its tunability is 150 nm.......A polarization maintaining filter based on a liquid-crystal-photonic-bandgap-fiber is demonstrated. Its polarization extinction ratio is 14 dB at 1550 nm. Its tunability is 150 nm....

Relation between anchorings of liquid crystals and conformation changes in aligning agents by the Langmuir-Blodgett film technique investigation

International Nuclear Information System (INIS)

Zhu, Y.; Lu, Z.; Wei, Y.

1995-01-01

The anchoring direction of liquid crystals on a solid substrate surface depends upon many parameters characterizing the liquid-crystal--substrate interface, a variation of which may change this anchoring direction leading to the so-called anchoring transition. Here, based on the Langmuir-Blodgett film technique, we present two model systems to study the relation between anchoring directions and the conformation changes in aligning agents. A double-armed crown ether liquid crystal and a side chain polymer liquid crystal at an air-water interface both show phase transitions, accompanied by conformation changes. However, when the monolayers in different phases were transferred onto solid substrates to orient liquid crystals, we found that for the crown ether material the conformation change can alter the anchoring of liquid crystals between homeotropic and homogeneous alignments, while for the polymer liquid crystal, despite the conformation changes, the liquid crystals can only be aligned homeotropically. The involved mechanisms were briefly discussed in terms of the Landau-type phenomenological theory

The ion capturing effect of 5° SiOx alignment films in liquid crystal devices

Science.gov (United States)

Huang, Yi; Bos, Philip J.; Bhowmik, Achintya

2010-09-01

We show that SiOx, deposited at 5° to the interior surface of a liquid crystal cell allows for a surprisingly substantial reduction in the ion concentration of liquid crystal devices. We have investigated this effect and found that this type of film, due to its surface morphology, captures ions from the liquid crystal material. Ion adsorption on 5° SiOx film obeys the Langmuir isotherm. Experimental results shown allow estimation of the ion capturing capacity of these films to be more than an order of 10 000/μm2. These types of materials are useful for new types of very low power liquid crystal devices such as e-books.

Heat and electrical conductivity of thermotropic liquid crystals

International Nuclear Information System (INIS)

Saidov, N.S.; Majidov, H.; Saburov, B.S.; Safarov, M.M.

1989-01-01

A results of thermal conduction and electrical conduction of chemo tropic liquid crystals are brought in this article. An installation dependence formula of thermal conduction investigating things from the electrical conduction and temperatures is constructed

Electrically tuned photoluminescence in large pitch cholesteric liquid crystal

International Nuclear Information System (INIS)

Middha, Manju; Kumar, Rishi; Raina, K. K.

2014-01-01

Cholesteric liquid crystals are known as 1-D photonic band gap materials due to their periodic helical supramolecular structure and larger birefringence. Depending upon the helical twisted pitch length, they give the characteristic contrast due to selective Bragg reflections when viewed through the polarizing optical microscope and hence affect the electro-optic properties. So the optimization of chiral dopant concentration in nematic liquid crystal leads to control the transmission of polarized light through the microscope. Hence transmission based polarizing optical microscope is used for the characterization of helical pitch length in the optical texture. The unwinding of helical pitch was observed with the application of electric field which affects the intensity of photoluminescence

Proton irradiation of liquid crystal based adaptive optical devices

International Nuclear Information System (INIS)

Buis, E.J.; Berkhout, G.C.G.; Love, G.D.; Kirby, A.K.; Taylor, J.M.; Hannemann, S.; Collon, M.J.

2012-01-01

To assess its radiation hardness, a liquid crystal based adaptive optical element has been irradiated using a 60 MeV proton beam. The device with the functionality of an optical beam steerer was characterised before, during and after the irradiation. A systematic set of measurements on the transmission and beam deflection angles was carried out. The measurements showed that the transmission decreased only marginally and that its optical performance degraded only after a very high proton fluence (10 10 p/cm 2 ). The device showed complete annealing in the functionality as a beam steerer, which leads to the conclusion that the liquid crystal technology for optical devices is not vulnerable to proton irradiation as expected in space.

Proton irradiation of liquid crystal based adaptive optical devices

Energy Technology Data Exchange (ETDEWEB)

Buis, E.J., E-mail: ernst-jan.buis@tno.nl [cosine Science and Computing BV, Niels Bohrweg 11, 2333 CA Leiden (Netherlands); Berkhout, G.C.G. [cosine Science and Computing BV, Niels Bohrweg 11, 2333 CA Leiden (Netherlands); Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands); Love, G.D.; Kirby, A.K.; Taylor, J.M. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Hannemann, S.; Collon, M.J. [cosine Research BV, Niels Bohrweg 11, 2333 CA Leiden (Netherlands)

2012-01-01

To assess its radiation hardness, a liquid crystal based adaptive optical element has been irradiated using a 60 MeV proton beam. The device with the functionality of an optical beam steerer was characterised before, during and after the irradiation. A systematic set of measurements on the transmission and beam deflection angles was carried out. The measurements showed that the transmission decreased only marginally and that its optical performance degraded only after a very high proton fluence (10{sup 10}p/cm{sup 2}). The device showed complete annealing in the functionality as a beam steerer, which leads to the conclusion that the liquid crystal technology for optical devices is not vulnerable to proton irradiation as expected in space.

A liquid-crystal-on-silicon color sequential display using frame buffer pixel circuits

Science.gov (United States)

Lee, Sangrok

Next generation liquid-crystal-on-silicon (LCOS) high definition (HD) televisions and image projection displays will need to be low-cost and high quality to compete with existing systems based on digital micromirror devices (DMDs), plasma displays, and direct view liquid crystal displays. In this thesis, a novel frame buffer pixel architecture that buffers data for the next image frame while displaying the current frame, offers such a competitive solution is presented. The primary goal of the thesis is to demonstrate the LCOS microdisplay architecture for high quality image projection displays and at potentially low cost. The thesis covers four main research areas: new frame buffer pixel circuits to improve the LCOS performance, backplane architecture design and testing, liquid crystal modes for the LCOS microdisplay, and system integration and demonstration. The design requirements for the LCOS backplane with a 64 x 32 pixel array are addressed and measured electrical characteristics matches to computer simulation results. Various liquid crystal (LC) modes applicable for LCOS microdisplays and their physical properties are discussed. One- and two-dimensional director simulations are performed for the selected LC modes. Test liquid crystal cells with the selected LC modes are made and their electro-optic effects are characterized. The 64 x 32 LCOS microdisplays fabricated with the best LC mode are optically tested with interface circuitry. The characteristics of the LCOS microdisplays are summarized with the successful demonstration.

Liquid gallium cooling of silicon crystals in high intensity photon beams

International Nuclear Information System (INIS)

Smither, R.K.; Forster, G.A.; Bilderback, D.H.; Bedzyk, M.; Finkelstein, K.; Henderson, C.; White, J.; Berman, L.E.; Stefan, P.; Oversluizen, T.

1989-01-01

The high-brilliance, insertion-device-based photon beams of the next generation of synchrotron sources (Argonne's APS and Grenoble's ESRF) will deliver large thermal loads (1--10 kW) to the first optical elements. Considering the problems that present synchrotron users are experiencing with beams from recently installed insertion devices, new and improved methods of cooling these first optical elements, particularly when they are diffraction crystals, are clearly needed. A series of finite element calculations were performed to test the efficiency of new cooling geometries and various cooling fluids. The best results were obtained with liquid Ga metal flowing in channels just below the surface of the crystal. Ga was selected because of its good thermal conductivity and thermal capacity, low melting point, high boiling point, low kinetic viscosity, and very low vapor pressure. Its very low vapor pressure, even at elevated temperatures, makes it especially attractive in UHV conditions. A series of experiments were conducted at CHESS in February of 1988 that compared liquid gallium-cooled silicon diffraction crystals with water-cooled crystals. A six-pole wiggler beam was used to perform these tests on three different Si crystals, two with new cooling geometries and the one presently in use. A special high-pressure electromagnetic induction pump, recently developed at Argonne, was used to circulate the liquid gallium through the silicon crystals. In all experiments, the specially cooled crystal was used as the first crystal in a two crystal monochromator. An infrared camera was used to monitor the thermal profiles and correlated them with rocking curve measurements. A second set of cooling experiments were conducted in June of 1988 that used the intense, highly collimated beam from the newly installed ANL/CHESS undulator

Synthesis and Characterization of Novel Ternary and Quaternary Alkali Metal Thiophosphates

KAUST Repository

Alahmary, Fatimah S.

2014-01-01

The ongoing development of nonlinear optical (NLO) crystals such as coherent mid-IR sources focuses on various classes of materials such as ternary and quaternary metal chalcophosphates. In case of thiophosphates, the connection between PS4

Ternary superconductors

International Nuclear Information System (INIS)

Giorgi, A.L.

1987-01-01

Ternary superconductors constitute a class of superconducting compounds with exceptional properties such as high transition temperatures (≅ 15.2 K), extremely high critical fields (H c2 >60 Tesla), and the coexistence of superconductivity and long-range magnetic order. This has generated great interest in the scientific community and resulted in a large number of experimental and theoretical investigations in which many new ternary compounds have been discovered. A review of some of the properties of these ternary compounds is presented with particular emphasis on the ternary molybdenum chalcogenides and the ternary rare earth transition metal tetraborides. The effect of partial substitution of a second metal atom to form pseudoternary compounds is examined as well as some of the proposed correlations between the superconducting transition temperature and the structural and electronic properties of the ternary superconductors

Single-Photon Source for Quantum Information Based on Single Dye Molecule Fluorescence in Liquid Crystal Host

International Nuclear Information System (INIS)

Lukishova, S.G.; Knox, R.P.; Freivald, P.; McNamara, A.; Boyd, R.W.; Stroud, Jr. C.R.; Schmid, A.W.; Marshall, K.L.

2006-01-01

This paper describes a new application for liquid crystals: quantum information technology. A deterministically polarized single-photon source that efficiently produces photons exhibiting antibunching is a pivotal hardware element in absolutely secure quantum communication. Planar-aligned nematic liquid crystal hosts deterministically align the single dye molecules which produce deterministically polarized single (antibunched) photons. In addition, 1-D photonic bandgap cholesteric liquid crystals will increase single-photon source efficiency. The experiments and challenges in the observation of deterministically polarized fluorescence from single dye molecules in planar-aligned glassy nematic-liquid-crystal oligomer as well as photon antibunching in glassy cholesteric oligomer are described for the first time

The Monte Carlo simulations of liquid crystal cell with bend distortions

International Nuclear Information System (INIS)

Zhou Xuan; Zhang Zhidong

2010-01-01

Strong anchoring nematic liquid crystal cell with bend distortions is studied, This liquid crystal cell has fast response in application prospects. The continuum theory has given that the surface elastic energy k 13 term causes surface discontinuities of the liquid crystal director. Study based on molecular theory, the pair potential parameters link directly to the surface elastic energy coefficient k 13 . The effect of finite temperature is studied by Monte Carlo simulation. The second rank ordering tensor is calculated, the largest eigenvalue gives the order parameter, and its corresponding eigenvector identifies the director in the continuum theory. It is shown that it doesn't present the surface discontinuities based on the molecular theory and the k 13 term in pair potential will increase the fluctuation in the middle of the cell. By inference, the boundary discontinuity caused by k 13 item in continuum theory is resulted from the neglecting of the higher items than the second rank of the elastic energy. (authors)

Dual gauge field theory of quantum liquid crystals in three dimensions

International Nuclear Information System (INIS)

Beekman, Aron J.; Nissinen, Jaakko; Wu, Kai; Zaanen, Jan

2017-01-01

The dislocation-mediated quantum melting of solids into quantum liquid crystals is extended from two to three spatial dimensions, using a generalization of boson-vortex or Abelian-Higgs duality. Dislocations are now Burgers-vector-valued strings that trace out worldsheets in space-time while the phonons of the solid dualize into two-form (Kalb-Ramond) gauge fields. We propose an effective dual Higgs potential that allows for restoring translational symmetry in either one, two, or three directions, leading to the quantum analogues of columnar, smectic, or nematic liquid crystals. In these phases, transverse phonons turn into gapped, propagating modes, while compressional stress remains massless. Rotational Goldstone modes emerge whenever translational symmetry is restored. Lastly, we also consider the effective electromagnetic response of electrically charged quantum liquid crystals, and find among other things that as a hard principle only two out of the possible three rotational Goldstone modes are observable using propagating electromagnetic fields.

Dual gauge field theory of quantum liquid crystals in three dimensions

Science.gov (United States)

Beekman, Aron J.; Nissinen, Jaakko; Wu, Kai; Zaanen, Jan

2017-10-01

The dislocation-mediated quantum melting of solids into quantum liquid crystals is extended from two to three spatial dimensions, using a generalization of boson-vortex or Abelian-Higgs duality. Dislocations are now Burgers-vector-valued strings that trace out worldsheets in space-time while the phonons of the solid dualize into two-form (Kalb-Ramond) gauge fields. We propose an effective dual Higgs potential that allows for restoring translational symmetry in either one, two, or three directions, leading to the quantum analogues of columnar, smectic, or nematic liquid crystals. In these phases, transverse phonons turn into gapped, propagating modes, while compressional stress remains massless. Rotational Goldstone modes emerge whenever translational symmetry is restored. We also consider the effective electromagnetic response of electrically charged quantum liquid crystals, and find among other things that as a hard principle only two out of the possible three rotational Goldstone modes are observable using propagating electromagnetic fields.

Ultraweak azimuthal anchoring of a nematic liquid crystal on a planar orienting photopolymer

International Nuclear Information System (INIS)

Nespoulous, Mathieu; Blanc, Christophe; Nobili, Maurizio

2007-01-01

The search of weak anchoring is an important issue for a whole class of liquid crystal displays. In this paper we present an orienting layer showing unreached weak planar azimuthal anchoring for 4-n-pentyl-4 ' -cyanobiphenyl nematic liquid crystal (5CB). Azimuthal extrapolation lengths as large as 80 μm are easily obtained. Our layers are made with the commercial photocurable polymer Norland optical adhesive 60. The anisotropy of the film is induced by the adsorption of oriented liquid crystal molecules under a 2 T magnetic field applied parallel to the surfaces. We use the width of surface π-walls and a high-field electro-optical method to measure, respectively, the azimuthal and the zenithal anchorings. The azimuthal anchoring is extremely sensitive to the ultraviolet (UV) dose and it also depends on the magnetic field application duration. On the opposite, the zenithal anchoring is only slightly sensitive to the preparation parameters. All these results are discussed in terms of the adsorption/desorption mechanisms of the liquid crystal molecules on the polymer layer and of the flexibility of the polymer network

Influence of RF power on performance of sputtered a-IGZO based liquid crystal cells

Energy Technology Data Exchange (ETDEWEB)

Wu, G.M., E-mail: wu@mail.cgu.edu.tw; Sahoo, A.K.; Liu, C.Y.

2015-12-01

The influence of radio-frequency (RF) power on sputter-deposited amorphous indium gallium zinc oxide (a-IGZO) films and the corresponding liquid crystal cell performances have been investigated. The inorganic films were used as alternative alignment layers for liquid crystal display cells. The columnar growth of film was achieved by non-contact, fixed oblique deposition using RF sputtering at the power of 50 W, 60 W and 70 W. The experiments have been carried out to compare the physical characteristics with those of the traditional polyimide (PI) alignment layers used for liquid crystal cells. The cell performances in voltage-transmittance, contrast ratio, and response time were all evaluated. The liquid crystal pretilt angle has been determined to be about 13° using 70 W power deposited a-IGZO film. It was 6° for the 60 W deposited film and only 1.5° for the PI alignment film. The experimental cell rise time and fall time was 1.25 ms and 2.96 ms, respectively. Thus, a very quick response time of 4.21 ms has been achieved. It was about 6.62 ms for the PI alignment control cell. - Highlights: • Radio-frequency power of indium gallium zinc oxide film deposition was studied. • The oblique deposition technique was used to prepare the alignment layers. • The liquid crystal pretilt angle was about 13° using 70 W. • The corresponding liquid crystal cells exhibited fast response time at 4.21 ms. • The cells showed low threshold voltage of 1.78 V and excellent contrast ratio.

Regularity of solutions to the liquid crystals systems in R2 and R3

International Nuclear Information System (INIS)

Dai, Mimi; Qing, Jie; Schonbek, Maria

2012-01-01

In this paper, we establish regularity and uniqueness for solutions to density dependent nematic liquid crystals systems. The results presented extend the regularity and uniqueness for constant density liquid crystals systems, obtained by Lin and Liu (1995 Commun. Pure Appl. Math. XLVIII 501–37)

Measuring of nonlinearity of dye doped liquid crystals using of self phase modulation effect

International Nuclear Information System (INIS)

Abedi, M.; Jafari, A.; Tajalli, H.

2007-01-01

Self phase modulation in dye doped liquid crystals has investigated and the nonlinearity of dye doped liquid crystals is measured by this effect. The Self phase modulation effect can be used for producing optical micro rings that have many applications in photonics and laser industries.

Blue Shifting Tuning of the Selective Reflection of Polymer Stabilized Cholesteric Liquid Crystals (Postprint)

Science.gov (United States)

2017-08-08

crystal (MLC-2079, Merck). The polymer stabi- lizing network was formed within the samples by photoinitiated polymerization with 50–700 mW cm2 of 365...AFRL-RX-WP-JA-2017-0347 BLUE-SHIFTING TUNING OF THE SELECTIVE REFLECTION OF POLYMER STABILIZED CHOLESTERIC LIQUID CRYSTALS (POSTPRINT...BLUE-SHIFTING TUNING OF THE SELECTIVE REFLECTION OF POLYMER STABILIZED CHOLESTERIC LIQUID CRYSTALS (POSTPRINT) 5a. CONTRACT NUMBER FA8650-16-F

Macroscopic chirality of a liquid crystal from nonchiral molecules

International Nuclear Information System (INIS)

Jakli, A.; Nair, G. G.; Lee, C. K.; Sun, R.; Chien, L. C.

2001-01-01

The transfer of chirality from nonchiral polymer networks to the racemic B2 phase of nonchiral banana-shaped molecules is demonstrated. This corresponds to the transfer of chirality from an achiral material to another achiral material. There are two levels of chirality transfers. (a) On a microscopic level the presence of a polymer network (chiral or nonchiral) favors a chiral state over a thermodynamically stable racemic state due to the inversion symmetry breaking at the polymer-liquid crystal interfaces. (b) A macroscopically chiral (enantimerically enriched) sample can be produced if the polymer network has a helical structure, and/or contains chemically chiral groups. The chirality transfer can be locally suppressed by exposing the liquid crystal to a strong electric field treatment

New structural studies of liquid crystal by reflectivity and resonant X-ray diffraction

International Nuclear Information System (INIS)

Fernandes, P.

2007-04-01

This memory presents three structural studies of smectic Liquid Crystals by reflectivity and resonant diffraction of X-rays. It is divided in five chapters. In the first a short introduction to Liquid Crystals is given. In particular, the smectic phases that are the object of this study are presented. The second chapter is consecrated to the X-ray experimental techniques that were used in this work. The three last chapters present the works on which this thesis can be divided. Chapter three demonstrates on free-standing films of MHPOBC (historic liquid crystal that possesses the antiferroelectric sub-phases) the possibility to extend the technique of resonant X-ray diffraction to liquid crystals without resonant element. In the fourth chapter the structure of the B 2 liquid crystal phase of bent-core molecules (or banana molecules) is elucidated by using resonant X-ray diffraction combined with polarization analysis of the diffracted beam. A model of the polarization of the resonant beam diffracted by four different structures proposed for the B 2 phase is developed in this chapter. In the fifth chapter a smectic binary mixture presenting a very original critical point of phase separation is studied by X-ray reflectivity and optical microscopy. A concentration gradient in the direction perpendicular to the plane of the film seems to be induced by the free-standing film geometry. The results of a simplified model of the system are compatible with this interpretation

High-pressure (vapour + liquid) equilibria for ternary systems composed by {(E)-2-hexenal or hexanal + carbon dioxide + water}: Partition coefficient measurement

International Nuclear Information System (INIS)

Bejarano, Arturo; López, Pablo I.; Valle, José M. del; Fuente, Juan C. de la

2015-01-01

Highlights: • A new apparatus based on a static–analytic method was assembled in this work. • This work reports high-pressure VLE data of (E)-2-hexenal or hexanal + CO 2 + water. • Data includes (CO 2 + water) partition coefficients of (E)-2-hexenal and hexanal. • High separation factors from water (∼10 4 ) were found especially for (E)-2-hexenal. • The data were obtained at T = (313, 323, and 333) K and pressures from (8 to 19) MPa. - Abstract: A new apparatus based on a static–analytic method assembled in this work was utilised to perform high-pressure (vapour + liquid) equilibria measurements of aqueous ternary systems. This work includes values of isothermal partition coefficients between CO 2 and water of two apple aroma constituents, (E)-2-hexenal and hexanal. Additionally, this work reports new experimental (vapour + liquid) equilibria measurements for the ternary systems (CO 2 + (E)-2-hexenal + water) and (CO 2 + hexanal + water), at fixed liquid phase composition (600 mg · kg −1 ), at temperatures of (313, 323 and 333) K and at pressures from (8 to 19) MPa. Vapour liquid interphase was checked and monitored visually for all the systems studied in this work. No liquid immiscibility was observed at the composition, temperatures and pressures studied. In order to suggest reasonable operation conditions for fractionation of aromas with dense carbon dioxide, partition coefficients of the aroma compounds between CO 2 and water along with their separation factors from water were calculated. Partition coefficients of (E)-2-hexenal between CO 2 and water were in the range of (6 to 91) and where found to be near six times higher than those of hexanal (9 to 17). Very high separation factors from water were observed (∼10 4 ) especially for (E)-2-hexenal. The highest separation factor, for both compounds, was found at a temperature of 313 K and pressures from (12 to 14) MPa

Density-viscosity product of small-volume ionic liquid samples using quartz crystal impedance analysis.

Science.gov (United States)

McHale, Glen; Hardacre, Chris; Ge, Rile; Doy, Nicola; Allen, Ray W K; MacInnes, Jordan M; Bown, Mark R; Newton, Michael I

2008-08-01

Quartz crystal impedance analysis has been developed as a technique to assess whether room-temperature ionic liquids are Newtonian fluids and as a small-volume method for determining the values of their viscosity-density product, rho eta. Changes in the impedance spectrum of a 5-MHz fundamental frequency quartz crystal induced by a water-miscible room-temperature ionic liquid, 1-butyl-3-methylimiclazolium trifluoromethylsulfonate ([C4mim][OTf]), were measured. From coupled frequency shift and bandwidth changes as the concentration was varied from 0 to 100% ionic liquid, it was determined that this liquid provided a Newtonian response. A second water-immiscible ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C4mim][NTf2], with concentration varied using methanol, was tested and also found to provide a Newtonian response. In both cases, the values of the square root of the viscosity-density product deduced from the small-volume quartz crystal technique were consistent with those measured using a viscometer and density meter. The third harmonic of the crystal was found to provide the closest agreement between the two measurement methods; the pure ionic liquids had the largest difference of approximately 10%. In addition, 18 pure ionic liquids were tested, and for 11 of these, good-quality frequency shift and bandwidth data were obtained; these 12 all had a Newtonian response. The frequency shift of the third harmonic was found to vary linearly with square root of viscosity-density product of the pure ionic liquids up to a value of square root(rho eta) approximately 18 kg m(-2) s(-1/2), but with a slope 10% smaller than that predicted by the Kanazawa and Gordon equation. It is envisaged that the quartz crystal technique could be used in a high-throughput microfluidic system for characterizing ionic liquids.

Alcohol-responsive, hydrogen-bonded, cholesteric liquid-crystal networks

NARCIS (Netherlands)

Chang, C.; Bastiaansen, C.W.M.; Broer, D.J.; Kuo, H.-L.

2012-01-01

Hydrogen-bridged, cholesteric liquid-crystal (CLC) polymer networks are adopted as an optical sensor material to distinguish between ethanol and methanol. Fast uptake of the alcohols is facilitated by an incorporated porosity created by breaking the hydrogen bridges and by a previously removed

Frequency tunability of solid-core photonic crystal fibers filled with nanoparticle-doped liquid crystals

OpenAIRE

Scolari, Lara; Gauza, Sebastian; Xianyu, Haiqing; Zhai, Lei; Eskildsen, Lars; Alkeskjold, Thomas Tanggaard; Wu, Shin-Tson; Bjarklev, Anders Overgaard

2009-01-01

We infiltrate liquid crystals doped with BaTiO3 nanoparticles in a photonic crystal fiber and compare the measured transmission spectrum with the one achieved without dopant. New interesting features, such as frequency modulation response of the device and a transmission spectrum with tunable attenuation on the short wavelength side of the widest bandgap, suggest a potential application of this device as a tunable all-in-fiber gain equalization filter with an adjustable slope. The tunability ...

Electric-field responsive contrast agent based on liquid crystals and magnetic nanoparticles

Science.gov (United States)

Mair, Lamar O.; Martinez-Miranda, Luz J.; Kurihara, Lynn K.; Nacev, Aleksandar; Hilaman, Ryan; Chowdhury, Sagar; Jafari, Sahar; Ijanaten, Said; da Silva, Claudian; Baker-McKee, James; Stepanov, Pavel Y.; Weinberg, Irving N.

2018-05-01

The properties of liquid crystal-magnetic nanoparticle composites have potential for sensing in the body. We study the response of a liquid crystal-magnetic nanoparticle (LC-MNP) composite to applied potentials of hundreds of volts per meter. Measuring samples using X-ray diffraction (XRD) and imaging composites using magnetic resonance imaging (MRI), we demonstrate that electric potentials applied across centimeter scale LC-MNP composite samples can be detected using XRD and MRI techniques.

A new method of liquid crystal thermometry excluding human color sensation

International Nuclear Information System (INIS)

Kunugi, Tomoaki; Akino, Norio; Ueda, Masaharu.

1987-01-01

Some choresteric liquid crystals can be used as a thermometer because of their color changes with varying temperatures. However, it is impossible to employ human color sensation for precise quantitative evaluation of temperature from their color. Therefore, a new method of liquid crystal thermometry is developed using narrow band optical filters and an image processor to exclude the employment of human color sensation. Relations between filter wavelength and temperature were determined by calibration tests. Two dimensional temperature distributions on a heated plate were successfully measured by the present method. (author)

Memory effect of polymer dispersed liquid crystal by hybridization with nanoclay

Directory of Open Access Journals (Sweden)

2010-01-01

Full Text Available The electro-optical performances of polymer dispersed liquid crystal (PDLC were investigated in the presence of organically modified clays. With the addition and increasing amount of modified clay, driving voltage and memory effect, viz. transparent state of the film after the electricity is off simultaneously increased due most likely to the increased viscosity. Among the two types of modifier, 4-(4-aminophenyl benzonitrile having greater chemical affinity with LC than hexylamine, gave finer dispersion of clay in liquid crystal, greater viscosity, larger driving voltage and response time, and greater memory effect.

Local structural ordering in surface-confined liquid crystals

Science.gov (United States)

Śliwa, I.; Jeżewski, W.; Zakharov, A. V.

2017-06-01

The effect of the interplay between attractive nonlocal surface interactions and attractive pair long-range intermolecular couplings on molecular structures of liquid crystals confined in thin cells with flat solid surfaces has been studied. Extending the McMillan mean field theory to include finite systems, it has been shown that confining surfaces can induce complex orientational and translational ordering of molecules. Typically, local smectic A, nematic, and isotropic phases have been shown to coexist in certain temperature ranges, provided that confining cells are sufficiently thick, albeit finite. Due to the nonlocality of surface interactions, the spatial arrangement of these local phases can display, in general, an unexpected complexity along the surface normal direction. In particular, molecules located in the vicinity of surfaces can still be organized in smectic layers, even though nematic and/or isotropic order can simultaneously appear in the interior of cells. The resulting surface freezing of smectic layers has been confirmed to occur even for rather weak surface interactions. The surface interactions cannot, however, prevent smectic layers from melting relatively close to system boundaries, even when molecules are still arranged in layers within the central region of the system. The internal interfaces, separating individual liquid-crystal phases, are demonstrated here to form fronts of local finite-size transitions that move across cells under temperature changes. Although the complex molecular ordering in surface confined liquid-crystal systems can essentially be controlled by temperature variations, specific thermal properties of these systems, especially the nature of the local transitions, are argued to be strongly conditioned to the degree of molecular packing.

A theory of the nematic liquid crystals

International Nuclear Information System (INIS)

Hazoume, R.P.

1980-09-01

A theory of the nematic phase of liquid crystals is presented, taking explicit account of the geometry of the molecule. The three broad peaks of the neutron scattering structure factor are explained. Expressions of the order parameters (average value of Psub(2L)) are given and they can be extracted by comparison with scattering experiments. (author)

Supramolecular Liquid Crystal Displays Construction and Applications

OpenAIRE

Hoogboom, J.T.V.

2004-01-01

This thesis describes chemical methodologies, which can be ued to construct alignment layers for liquid crystal display purposes in a non-clean room environment, by making use of supramolecular chemistry. These techniques are subsequently used to attain control over LCD-properties, both pre- and post-LCD construction. In addition, the thesis describes the application of LCD technology in biosensors.

Recent advances in IR liquid crystal spatial light modulators

Science.gov (United States)

Peng, Fenglin; Twieg, Robert J.; Wu, Shin-Tson

2015-09-01

Liquid crystal (LC) is an amazing class of electro-optic media; its applications span from visible to infrared, millimeter wave, and terahertz regions. In the visible and short-wavelength infrared (SWIR) regions, most LCs are highly transparent. However, to extend the electro-optic application of LCs into MWIR and LWIR, several key technical challenges have to be overcome: (1) low absorption loss, (2) high birefringence, (3) low operation voltage, and (4) fast response time. In the MWIR and LWIR regions, several fundamental molecular vibration bands and overtones exist, which contribute to high absorption loss. The absorbed light turns to heat and then alters the birefringence locally, which in turns causes spatially non-uniform phase modulation. To suppress the optical loss, several approaches have been investigated: (1) Employing thin cell gap by choosing a high birefringence LC mixture; (2) Shifting the absorption bands outside the spectral region of interest by deuteration, fluorination, or chlorination; (3) Reducing the overtone absorption by using a short alkyl chain. In this paper, we report some recently developed chlorinated LC compounds and mixtures with low absorption loss in the SWIR and MWIR regions. To achieve fast response time, we demonstrated a polymer network liquid crystal with 2π phase change at MWIR and response time less than 5 ms. Approaches to extend such a liquid crystal spatial light modulator to long-wavelength infrared will be discussed.

Bismuth-ceramic nanocomposites through ball milling and liquid crystal synthetic methods

Science.gov (United States)

Dellinger, Timothy Michael

Three methods were developed for the synthesis of bismuth-ceramic nanocomposites, which are of interest due to possible use as thermoelectric materials. In the first synthetic method, high energy ball milling of bismuth metal with either MgO or SiO2 was found to produce nanostructured bismuth dispersed on a ceramic material. The morphology of the resulting bismuth depended on its wetting behavior with respect to the ceramic: the metal wet the MgO, but did not wet on the SiO2. Differential Scanning Calorimetry measurements on these composites revealed unusual thermal stability, with nanostructure retained after multiple cycles of heating and cooling through the metal's melting point. The second synthesis methodology was based on the use of lyotropic liquid crystals. These mixtures of water and amphiphilic molecules self-assemble to form periodic structures with nanometer-scale hydrophilic and hydrophobic domains. A novel shear mixing methodology was developed for bringing together reactants which were added to the liquid crystals as dissolved salts. The liquid crystals served to mediate synthesis by acting as nanoreactors to confine chemical reactions within the nanoscale domains of the mesophase, and resulted in the production of nanoparticles. By synthesizing lead sulfide (PbS) and bismuth (Bi) particles as proof-of-concept, it was shown that nanoparticle size could be controlled by controlling the dimensionality of the nanoreactors through control of the liquid crystalline phase. Particle size was shown to decrease upon going from three-dimensionally percolating nanoreactors, to two dimensional sheet-like nanoreactors, to one dimensional rod-like nanoreactors. Additionally, particle size could be controlled by varying the precursor salt concentration. Since the nanoparticles did not agglomerate in the liquid crystal immediately after synthesis, bismuth-ceramic nanocomposites could be prepared by synthesizing Bi nanoparticles and mixing in SiO2 particles which

Investigation of the La2O3-Nb2O5-WO3 ternary phase diagram: Isolation and crystal structure determination of the original La3NbWO10 material

KAUST Repository

Vu, T.D.; Vu, T.D.; Barre, M.; Adil, Karim; Jouanneaux, A.; Suard, E.; Goutenoire, F.

2015-01-01

In the course of the exploration of the La2O3-WO3-Nb2O5 ternary phase diagram, a new compound with the formula La3NbWO10 was discovered. Its structure was determined from a combination of powder X-ray and neutron diffraction data. It crystallizes

Theory of liquid crystal elastomers and polymer networks : Connection between neoclassical theory and differential geometry.

Science.gov (United States)

Nguyen, Thanh-Son; Selinger, Jonathan V

2017-09-01

In liquid crystal elastomers and polymer networks, the orientational order of liquid crystals is coupled with elastic distortions of crosslinked polymers. Previous theoretical research has described these materials through two different approaches: a neoclassical theory based on the liquid crystal director and the deformation gradient tensor, and a geometric elasticity theory based on the difference between the actual metric tensor and a reference metric. Here, we connect those two approaches using a formalism based on differential geometry. Through this connection, we determine how both the director and the geometry respond to a change of temperature.

Electrotransport in ionic crystals: Pt. 1. Application of liquid electrolyte theory

International Nuclear Information System (INIS)

Janek, J.

1994-01-01

Transport of matter and charge in ionic crystals is only possible by the existence of irregular structure elements (defects) which are often charged relative to the crystal lattice. A comparison between the transport behaviour of a crystalline matrix containing such charged defects and a liquid electrolyte containing dissolved ions shows a lot of similarities. As is well known the transport properties of liquid electrolytes are strongly affected by interactions between the dissolved ions. We have applied the well elaborated concept of mixed electrolytes by Onsager and Fuoss which was originally devoted to liquid electrolytes to ionic crystals containing charged point defects. The equations of Onsager and Fuoss allow in principle the calculation of the concentration dependence of the phenomenological transport coefficients L ij of all charge carriers of n-component electrolytes. We will use these equations to predict the transport behaviour of ionic crystals containing differently charged point defects. As examples we have calculated transport coefficients for electrolyte systems which can be regarded as models for the transition metal oxides Co 1-δ O and Cu 2-δ O. One major result concerns the magnitude of the cross effect between the ionic and electronic fluxes in those materials. The implications of these results with respect to experimental observations are discussed. (orig.)

Prediction of high-Tc conventional superconductivity in the ternary lithium borohydride system

Science.gov (United States)

Kokail, Christian; von der Linden, Wolfgang; Boeri, Lilia

2017-12-01

We investigate the superconducting ternary lithium borohydride phase diagram at pressures of 0 and 200 GPa using methods for evolutionary crystal structure prediction and linear-response calculations for the electron-phonon coupling. Our calculations show that the ground state phase at ambient pressure, LiBH4, stays in the P n m a space group and remains a wide band-gap insulator at all pressures investigated. Other phases along the 1 :1 :x Li:B:H line are also insulating. However, a full search of the ternary phase diagram at 200 GPa revealed a metallic Li2BH6 phase, which is thermodynamically stable down to 100 GPa. This superhydride phase, crystallizing in a F m 3 ¯m space group, is characterized by sixfold hydrogen-coordinated boron atoms occupying the fcc sites of the unit cell. Due to strong hydrogen-boron bonding this phase displays a critical temperature of ˜100 K between 100 and 200 GPa. Our investigations confirm that ternary compounds used in hydrogen-storage applications should exhibit high-Tc conventional superconductivity in diamond anvil cell experiments, and suggest a viable route to optimize the superconducting behavior of high-pressure hydrides, exploiting metallic covalent bonds.

Some problems of the statistical theory of polymeric lyotropic liquid crystals

International Nuclear Information System (INIS)

Grosberg, A.Yu.; Khokhlov, A.R.

1980-06-01

In this article we consider some topics of the statistical physics of liquid-crystalline phase in the solutions of stiff chain macromolecules. Among these topics are: the problem of the phase diagram for the liquid-crystalline transition in the solutions of completely stiff macromolecules (rigid rods); conditions of formation of the liquid-crystalline phase in the solutions of semiflexible macromolecules; possibility of the intramolecular liquid-crystalline ordering in semiflexible macromolecules; structure of intramolecular liquid crystals and dependence of the properties of the liquid-crystalline phase on the microstructure of the polymer chain. (author)

Optical tuning of photonic bandgaps in dye-doped nematic liquid crystal photonic crystal fibers

DEFF Research Database (Denmark)

Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard; Hermann, David Sparre

2005-01-01

An all-optical modulator is demonstrated, which utilizes a pulsed 532 nm laser to modulate the spectral position of the bandgaps in a photonic crystal fiber infiltrated with a dye-doped nematic liquid crystal. In order to investigate the time response of the LCPBG fiber device, a low-power CW probe...... laser was coupled into the fiber together with the pulsed pump laser of 2.3 mW and we have demonstrated a modulation frequency of up to 2 kHz....

Magneto-optic dynamics in a ferromagnetic nematic liquid crystal

OpenAIRE

Potisk, Tilen; Mertelj, Alenka; Sebastian, Nerea; Osterman, Natan; Lisjak, Darja; Brand, Helmut R.; Pleiner, Harald; Svenšek, Daniel

2018-01-01

We investigate dynamic magneto-optic effects in a ferromagnetic nematic liquid crystal experimentally and theoretically. Experimentally we measure the magnetization and the phase difference of the transmitted light when an external magnetic field is applied. As a model we study the coupled dynamics of the magnetization, M, and the director field, n, associated with the liquid crystalline orientational order. We demonstrate that the experimentally studied macroscopic dynamic behavior reveals t...

Geometrical optics approach in liquid crystal films with three-dimensional director variations.

Science.gov (United States)

Panasyuk, G; Kelly, J; Gartland, E C; Allender, D W

2003-04-01

A formal geometrical optics approach (GOA) to the optics of nematic liquid crystals whose optic axis (director) varies in more than one dimension is described. The GOA is applied to the propagation of light through liquid crystal films whose director varies in three spatial dimensions. As an example, the GOA is applied to the calculation of light transmittance for the case of a liquid crystal cell which exhibits the homeotropic to multidomainlike transition (HMD cell). Properties of the GOA solution are explored, and comparison with the Jones calculus solution is also made. For variations on a smaller scale, where the Jones calculus breaks down, the GOA provides a fast, accurate method for calculating light transmittance. The results of light transmittance calculations for the HMD cell based on the director patterns provided by two methods, direct computer calculation and a previously developed simplified model, are in good agreement.

Thermal expansion accompanying the glass-liquid transition and crystallization

Directory of Open Access Journals (Sweden)

M. Q. Jiang

2015-12-01

Full Text Available We report the linear thermal expansion behaviors of a Zr-based (Vitreloy 1 bulk metallic glass in its as-cast, annealed and crystallized states. Accompanying the glass-liquid transition, the as-cast Vitreloy 1 shows a continuous decrease in the thermal expansivity, whereas the annealed glass shows a sudden increase. The crystallized Vitreloy 1 exhibits an almost unchanged thermal expansivity prior to its melting. Furthermore, it is demonstrated that the nucleation of crystalline phases can induce a significant thermal shrinkage of the supercooled liquid, but with the growth of these nuclei, the thermal expansion again dominates. These results are explained in the framework of the potential energy landscape, advocating that the configurational and vibrational contributions to the thermal expansion of the glass depend on both, structure and temperature.

Polymer Stabilization of Liquid-Crystal Blue Phase II toward Photonic Crystals.

Science.gov (United States)

Jo, Seong-Yong; Jeon, Sung-Wook; Kim, Byeong-Cheon; Bae, Jae-Hyun; Araoka, Fumito; Choi, Suk-Won

2017-03-15

The temperature ranges where a pure simple-cubic blue phase (BPII) emerges are quite narrow compared to the body-centered-cubic BP (BPI) such that the polymer stabilization of BPII is much more difficult. Hence, a polymer-stabilized BPII possessing a wide temperature range has been scarcely reported. Here, we fabricate a polymer-stabilized BPII over a temperature range of 50 °C including room temperature. The fabricated polymer-stabilized BPII is confirmed via polarized optical microscopy, Bragg reflection, and Kossel diagram observations. Furthermore, we demonstrate reflective BP liquid-crystal devices utilizing the reflectance-voltage performance as a potential application of the polymer-stabilized BPII. Our work demonstrates the possibility of practical application of the polymer-stabilized BPII to photonic crystals.

Dichroic Liquid Crystal Displays

Science.gov (United States)

Bahadur, Birendra

The following sections are included: * INTRODUCTION * DICHROIC DYES * Chemical Structure * Chemical and Photochemical Stability * THEORETICAL MODELLING * DEFECTS CAUSED BY PROLONGED LIGHT IRRADIATION * CHEMICAL STRUCTURE AND PHOTOSTABILITY * OTHER PARAMETERS AFFECTING PHOTOSTABILITY * CELL PREPARATION * DICHROIC PARAMETERS AND THEIR MEASUREMENTS * Order Parameter and Dichroic Ratio Of Dyes * Absorbance, Order Parameter and Dichroic Ratio Measurements * IMPACT OF DYE STRUCTURE AND LIQUID CRYSTAL HOST ON PHYSICAL PROPERTIES OF A DICHROIC MIXTURE * Order Parameter and Dichroic Ratio * EFFECT OF LENGTH OF DICHROIC DYES ON THE ORDER PARAMETER * EFFECT OF THE BREADTH OF DYE ON THE ORDER PARAMETER * EFFECT OF THE HOST ON THE ORDER PARAMETER * TEMPERATURE VARIATION OF THE ORDER PARAMETER OF DYES IN A LIQUID CRYSTAL HOST * IMPACT OF DYE CONCENTRATION ON THE ORDER PARAMETER * Temperature Range * Viscosity * Dielectric Constant and Anisotropy * Refractive Indices and Birefringence * solubility43,153-156 * Absorption Wavelength and Auxochromic Groups * Molecular Engineering of Dichroic Dyes * OPTICAL, ELECTRO-OPTICAL AND LIFE PARAMETERS * Colour And CIE Colour space120,160-166 * CIE 1931 COLOUR SPACE * CIE 1976 CHROMATICITY DIAGRAM * CIE UNIFORM COLOUR SPACES & COLOUR DIFFERENCE FORMULAE120,160-166 * Electro-Optical Parameters120 * LUMINANCE * CONTRAST AND CONTRAST RATIO * SWITCHING SPEED * Life Parameters and Failure Modes * DICHROIC MIXTURE FORMULATION * Monochrome Mixture * Black Mixture * ACHROMATIC BLACK MIXTURE FOR HEILMEIER DISPLAYS * Effect of Illuminant on Display Colour * Colour of the Field-On State * Effect of Dye Linewidth * Optimum Centroid Wavelengths * Effect of Dye Concentration * Mixture Formulation Using More Than Three Dyes * ACHROMATIC MIXTURE FOR WHITE-TAYLOR TYPE DISPLAYS * HEILMEIER DISPLAYS * Theoretical Modelling * Threshold Characteristic * Effects of Dye Concentration on Electro-optical Parameters * Effect of Cholesteric Doping * Effect of Alignment

Magnetic Nanoparticle-Assisted Tunable Optical Patterns from Spherical Cholesteric Liquid Crystal Bragg Reflectors

OpenAIRE

Lin, Yali; Yang, Yujie; Shan, Yuwei; Gong, Lingli; Chen, Jingzhi; Li, Sensen; Chen, Lujian

2017-01-01

Cholesteric liquid crystals (CLCs) exhibit selective Bragg reflections of circularly polarized (CP) light owing to their spontaneous self-assembly abilities into periodic helical structures. Photonic cross-communication patterns could be generated toward potential security applications by spherical cholesteric liquid crystal (CLC) structures. To endow these optical patterns with tunability, we fabricated spherical CLC Bragg reflectors in the shape of microshells by glass-capillary microfluidi...

Alignment of carbon nanotubes in nematic liquid crystals

NARCIS (Netherlands)

Schoot, van der P.P.A.M.; Popa-Nita, V.; Kralj, S.

2008-01-01

The self-organizing properties of nematic liquid crystals can be used to align carbon nanotubes dispersed in them. Because the nanotubes are so much thinner than the elastic penetration length, the alignment is caused by the coupling of the unperturbed director field to the anisotropic interfacial

Optical monitoring of gases with cholesteric liquid crystals

NARCIS (Netherlands)

Han, Y.; Pacheco Morillo, K.B.; Bastiaansen, C.W.M.; Broer, D.J.; Sijbesma, R.P.

2010-01-01

A new approach to optical monitors for gases is introduced using cholesteric liquid crystals doped with reactive chiral compounds. The approach is based on cholesteric pitch length changes caused by a change in helical twisting power (HTP) of the chiral dopants upon reaction with the analyte. The

The study of the elasticity of spider dragline silk with liquid crystal model

International Nuclear Information System (INIS)

Cui Linying; Liu Fei; Ouyang Zhongcan

2009-01-01

Spider dragline silk is an optimal biomaterial with a combination of high tensile strength and high elasticity, and it has long been suggested to belong to liquid crystalline materials. However, a satisfactory liquid crystal description for the mechanical properties of the dragline is still missing. To solve the long existing problem, we generalized the Maier-Saupe theory of nematics to construct a liquid crystal model of the deformation mechanism of the dragline silk. We show that the remarkable elasticity of the dragline can be understood as the isotropic-nematic phase transition of the chain network with the beginning of the transition corresponding to the yield point. The calculated curve fits well with the measurements and the yield point is obtained self-consistently within our framework. The present theory can also qualitatively account for the drop of stress in supercontracted spider silk. All these comprehensive agreements between theory and experiments strongly indicate the dragline to belong to liquid crystal materials.

Charge Transport and Phase Behavior of Imidazolium-Based Ionic Liquid Crystals from Fully Atomistic Simulations.

Science.gov (United States)

Quevillon, Michael J; Whitmer, Jonathan K

2018-01-02

Ionic liquid crystals occupy an intriguing middle ground between room-temperature ionic liquids and mesostructured liquid crystals. Here, we examine a non-polarizable, fully atomistic model of the 1-alkyl-3-methylimidazolium nitrate family using molecular dynamics in the constant pressure-constant temperature ensemble. These materials exhibit a distinct "smectic" liquid phase, characterized by layers formed by the molecules, which separate the ionic and aliphatic moieties. In particular, we discuss the implications this layering may have for electrolyte applications.

Les polymères auto-renforcés à cristaux liquides Self-Reinforcing Liquid-Crystal Polymers

Directory of Open Access Journals (Sweden)

Dorbon M.

2006-11-01

Full Text Available Les polymères auto-renforcés à cristaux liquides (PARCL sont des matériaux dont les molécules, des polymères organiques, sont susceptibles de s'auto-orienter les unes par rapport aux autres. Cette propriété leur confère des caractéristiques mécaniques proches de celles des acier: pour des poids plus faibles sans qu'il soit nécessaire d'avoir recours à des fibres renforçantes. Il existe deux types de PARCL: ceux pouvant s'orienter en solution, qualifiés de lyotropiques, et ceux pouvant s'orienter à l'état fondu, appelés thermotropiques. Des fibres en poly (p-phénylène térephtalamide PPT, PARCL de type lyotropique, sont disponibles commercialement et connaissent déjà de nombreuses applications. Les PARCL thermotropiques n'existent pas encore sur le marché mais sont porteurs de nombreux espoirs car ils sont susceptibles d'être moulés et donc de prendre les formes les plus diverses, ce qui n'est pas le cas de ceux de type lyotropique. Self-reinforcing liquid-crystal polymers are materials in which the molecules, i. e. organic polymers, are capable of orienting themselves in relation to one another. This property gives them mechanical characteristics close to those of steels yet of much less weight without having to use reinforcing fibers. There are two types of self-reinforcing liquid-crystal polymers: (i those capable of orienting themselves in solution, called Iyotropic, and (ii those capable of orienting themselves in a molten state, called thermotropic. Poly (p-phenylene terephthalamide fibers, self-reinforcing liquid-crystal polymers of the Iyotropic type, are commercially available and have already found numerous applications. Thermotropic self-reinforcing liquid-crystal polymers are not yet on the market but seem to be very promising because they are capable of being molded and hence of taking on a wide variety of shapes, which is not the case of those of the lyotropic type.

Liquid Crystal Mediated Nano-assembled Gold Micro-shells

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Quint, Makiko; Sarang, Som; Quint, David; Huang, Kerwyn; Gopinathan, Ajay; Hirst, Linda; Ghosh, Sayantani

We have created 3D nano-assenbled micro-shell by using thermotropic liquid crystal (LC), 4-Cyano-4'-pentylbiphenyl (5CB), doped with mesogen-functionalized gold nanoparticles (AuNPs). The assembly process is driven by the isotropic-nematic phase transition dynamics. We uniformly disperse the functionalized AuNPs into isotropic liquid crystal matrix and the mixture is cooled from the isotropic to the nematic phase. During the phase transition, the separation of LC-AuNP rich isotropic and ordered 5CB rich domains cause the functionalized AuNPs to move into the shrinking isotropic regions. The mesogenic ligands are locally crystalized during this process, which leads to the formation of a spherical shell with a densely packed wall of AuNPs. These micro-shells are capable of encapsulating fluorescence dye without visible leakages for several months. Additionally, they demonstrate strong localized surface plasmon resonance, which leads to localized heating on optical excitation. This photothermal effect disrupts the structure, releasing contents within seconds. Our results exhibiting the capture and optically regulated release of encapsulated substances is a novel platform that combines drug-delivery and photothermal therapy in one versatile and multifunctional unit. This work is supported by the NSF Grants No. DMR-1056860, ECC-1227034, and a University of California Merced Faculty Mentor Fellowship.

Thermodynamic properties of a liquid crystal carbosilane dendrimer

Science.gov (United States)

Samosudova, Ya. S.; Markin, A. V.; Smirnova, N. N.; Ogurtsov, T. G.; Boiko, N. I.; Shibaev, V. P.

2016-11-01

The temperature dependence of the heat capacity of a first-generation liquid crystal carbosilane dendrimer with methoxyphenyl benzoate end groups is studied for the first time in the region of 6-370 K by means of precision adiabatic vacuum calorimetry. Physical transformations are observed in this interval of temperatures, and their standard thermodynamic characteristics are determined and discussed. Standard thermodynamic functions C p ° ( T), H°( T) - H°(0), S°( T) - S°(0), and G°( T) - H°(0) are calculated from the obtained experimental data for the region of T → 0 to 370 K. The standard entropy of formation of the dendrimer in the partially crystalline state at T = 298.15 K is calculated, and the standard entropy of the hypothetic reaction of its synthesis at this temperature is estimated. The thermodynamic properties of the studied dendrimer are compared to those of second- and fourth-generation liquid crystal carbosilane dendrimers with the same end groups studied earlier.

Experimental (liquid + liquid) equilibrium data for ternary and quaternary mixtures of fatty acid methyl and ethyl esters (FAME/FAEE) from soybean oil

International Nuclear Information System (INIS)

Beneti, Stéphani C.; Lanza, Marcelo; Mazutti, Marcio A.; Kunita, Marcos Hiroiuqui; Cardozo-Filho, Lúcio; Vladimir Oliveira, J.

2014-01-01

Highlights: • Innovative technique for quantification of compounds involved in the biodiesel production. • Easy and quick determination from NIR combined with multivariate calibration. • Reliable LLE correlation and predictions can be attained from the technique. -- Abstract: This work is aimed at providing an easy and quick determination of the biodiesel products using near infrared spectroscopy (NIR) by combination with the multivariate calibration in the analysis of (liquid + liquid) equilibrium (LLE) data for ternary and quaternary mixtures containing soybean fatty acid methyl (FAME) and ethyl (FAEE) esters, glycerol, ethanol, methanol and water, at various temperatures. The mass balance for the compositions obtained for each phase was carried out so as to demonstrate the reliability of the models generated by the multivariate calibration. Two distinct phases are observed, a glycerol-rich and the other ester-rich, while ethanol is dissolved among the phases hence reducing the partial mutual miscibility between glycerol and ester. Through (liquid + liquid) equilibrium (LLE) results, systems containing FAEE at T = 318.15 K and 303.15 K (calibration using data obtained at temperature of 318.15 K), a good agreement is verified among the values determined using conventional and NIR technique for alcoholic phase (AP) or aqueous phase (WP) and biodiesel phase (BP). Likewise in the systems containing FAME at 318.15 K, 303.15 K and 333.15 K (calibration using data obtained at temperature of 318.15 K), the LLE results were reproduced at the upper and lower temperature to the tests of the reproducibility of the models generated by the multivariate calibration

Phase transitions on (liquid + liquid) equilibria for (water + 1-methylnaphthalene + light aromatic hydrocarbon) ternary systems at T = (563, 573, and 583) K

International Nuclear Information System (INIS)

Togo, Masaki; Inamori, Yoshiki; Shimoyama, Yusuke

2012-01-01

Highlights: ► Mixtures of (water + 1-methylnaphthalene + light aromatic hydrocarbon) are focused. ► Phase transition pressures on (liquid + liquid) equilibria were measured. ► Effects of aromatic hydrocarbons on phase transition pressure are investigated. ► Phase transition pressures are discussed using dielectric constants of hydrocarbons. - Abstract: Phase transitions for (water + 1-methylnaphthalene + light aromatic hydrocarbon) ternary systems are observed at their (liquid + liquid) equilibria at T = (563, 573, and 583) K and (8.6 to 25.0) MPa. The phase transition pressures at T = (563, 573, and 583) K were measured for the five species of light aromatic hydrocarbons, o-, m-, p-xylenes, ethylbenzene, and mesitylene. The measurements of the phase transition pressures were carried out by changing the feed mole fraction of water and 1-methylnaphthalene in water free, respectively. Effects of the feed mole fraction of water on the phase transition pressures are very small. Increasing the feed mole fraction of 1-methylnaphthalene results in decreasing the phase transition pressures at constant temperature. The slopes depending on the feed mole fraction for 1-methylnaphthalene at the phase transition pressures are decreased with increasing temperature for (water + 1-methylnaphthalene + p-xylene), (water + 1-methylnaphthalene + o-xylene), and (water + 1-methylnaphthalene + mesitylene) systems. For xylene isomers, the highest and lowest of the phase transition pressures are obtained in the case of p- and o-xylenes, respectively. The phase transition pressures for ethylbenzene are lower than those in the case of p-xylene. The similar phase transition pressures are given for p-xylene and mesitylene.

Experimental investigation of phase equilibria in the Zr-Cu-Ni ternary system

International Nuclear Information System (INIS)

Yang, Mujin; Wang, Cuiping; Yang, Shuiyuan; Shi, Zhan; Han, Jiajia; Liu, Xingjun

2017-01-01

The phase equilibria in the Zr-Cu-Ni ternary system are investigated combined with X-ray diffraction, electron probe micro-analysis and differential scanning calorimetry. Two isothermal sections of the Zr-Cu-Ni ternary system at 1 000 C and 1 100 C are experimentally established. Most of the binary intermetallic compounds, e.g. Zr 7 Ni 10 , ZrNi, ZrNi 5 , Zr 14 Cu 51 , and Zr 2 Cu 9 , show a remarkable ternary solubility. A new ternary compound named τ 3 (Zr 31.1-30.7 . Cu 28.5-40.3 Ni 40.4-29.0 ) is detected at 1 000 C and dissolved at 1 020 C because the nearby large liquid phase field further expands. The newly determined phase equilibria will provide important information for both thermodynamic assessment and alloy design of Zr-based metallic glass.

A new polymer electrolyte based on a discotic liquid crystal triblock copolymer

International Nuclear Information System (INIS)

Stoeva, Zlatka; Lu, Zhibao; Ingram, Malcolm D.; Imrie, Corrie T.

2013-01-01

A discotic liquid crystal triblock copolymer consisting of a central main chain triphenylene-based liquid crystal block capped at both ends by blocks of poly(ethylene oxide) (PEO) (M W = 2000 g mol −1 ) has been doped with lithium perchlorate in an EO:Li 6:1 ratio. The polymer electrolyte exhibits a phase separated morphology consisting of a columnar hexagonal liquid crystal phase and PEO-rich regions. The polymer electrolyte forms self-supporting, solid-like films. The ionic conductivity on initial heating of the sample is very low below ca. 60 °C but increases rapidly above this temperature. This is attributed to the melting of crystalline PEO-rich regions. Crystallisation is suppressed on cooling, and subsequent heating cycles exhibit higher conductivities but still less than those measured for the corresponding lithium perchlorate complex in poly(ethylene glycol) (M W = 2000 g mol −1 ). Instead the triblock copolymer mimics the behaviour of high molecular weight poly(ethylene oxide) (M W = 300,000 g mol −1 ). This is attributed, in part, to the anchoring of the short PEG chains to the liquid crystal block which prevents their diffusion through the sample. Temperature and pressure variations in ion mobility indicate that the ion transport mechanism in the new material is closely related to that in the conventional PEO-based electrolyte, opening up the possibility of engineering enhanced conductivities in future

NATO Advanced Study Institute on Advances in the Computer Simulations of Liquid Crystals

CERN Document Server

Zannoni, Claudio

2000-01-01

Computer simulations provide an essential set of tools for understanding the macroscopic properties of liquid crystals and of their phase transitions in terms of molecular models. While simulations of liquid crystals are based on the same general Monte Carlo and molecular dynamics techniques as are used for other fluids, they present a number of specific problems and peculiarities connected to the intrinsic properties of these mesophases. The field of computer simulations of anisotropic fluids is interdisciplinary and is evolving very rapidly. The present volume covers a variety of techniques and model systems, from lattices to hard particle and Gay-Berne to atomistic, for thermotropics, lyotropics, and some biologically interesting liquid crystals. Contributions are written by an excellent panel of international lecturers and provides a timely account of the techniques and problems in the field.

Electrically switchable photonic liquid crystal devices for routing of a polarized light wave

Science.gov (United States)

Rushnova, Irina I.; Melnikova, Elena A.; Tolstik, Alexei L.; Muravsky, Alexander A.

2018-04-01

The new mode of LC alignment based on photoalignment AtA-2 azo dye where the refractive interface between orthogonal orientations of the LC director exists without voltage and disappeared or changed with critical voltage has been proposed. The technology to fabricate electrically controlled liquid crystal elements for spatial separation and switching of linearly polarized light beams on the basis of the total internal reflection effect has been significantly improved. Its distinctive feature is the application of a composite alignment material comprising two sublayers of Nylon-6 and AtA-2 photoalignment azo dye offering patterned liquid crystal director orientation with high alignment quality value q = 0 . 998. The fabricated electrically controlled spatially structured liquid crystal devices enable implementation of propagation directions separation for orthogonally polarized light beams and their switching with minimal crosstalk.

Beam-splitter switches based on zenithal bistable liquid-crystal gratings.

Science.gov (United States)

Zografopoulos, Dimitrios C; Beccherelli, Romeo; Kriezis, Emmanouil E

2014-10-01

The tunable optical diffractive properties of zenithal bistable nematic liquid-crystal gratings are theoretically investigated. The liquid-crystal orientation is rigorously solved via a tensorial formulation of the Landau-de Gennes theory and the optical transmission properties of the gratings are investigated via full-wave finite-element frequency-domain simulations. It is demonstrated that by proper design the two stable states of the grating can provide nondiffracting and diffracting operation, the latter with equal power splitting among different diffraction orders. An electro-optic switching mechanism, based on dual-frequency nematic materials, and its temporal dynamics are further discussed. Such gratings provide a solution towards tunable beam-steering and beam-splitting components with extremely low power consumption.

Modeling diffusion-governed solidification of ternary alloys - Part 2: Macroscopic transport phenomena and macrosegregation.

Science.gov (United States)

Wu, M; Li, J; Ludwig, A; Kharicha, A

2014-09-01

Part 1 of this two-part investigation presented a multiphase solidification model incorporating the finite diffusion kinetics and ternary phase diagram with the macroscopic transport phenomena (Wu et al., 2013). In Part 2, the importance of proper treatment of the finite diffusion kinetics in the calculation of macrosegregation is addressed. Calculations for a two-dimensional (2D) square casting (50 × 50 mm 2 ) of Fe-0.45 wt.%C-1.06 wt.%Mn considering thermo-solutal convection and crystal sedimentation are performed. The modeling result indicates that the infinite liquid mixing kinetics as assumed by classical models (e.g., the Gulliver-Scheil or lever rule), which cannot properly consider the solute enrichment of the interdendritic or inter-granular melt at the early stage of solidification, might lead to an erroneous estimation of the macrosegregation. To confirm this statement, further theoretical and experimental evaluations are desired. The pattern and intensity of the flow and crystal sedimentation are dependent on the crystal morphologies (columnar or equiaxed); hence, the potential error of the calculated macrosegregation caused by the assumed growth kinetics depends on the crystal morphology. Finally, an illustrative simulation of an engineering 2.45-ton steel ingot is performed, and the results are compared with experimental results. This example demonstrates the model applicability for engineering castings regarding both the calculation efficiency and functionality.

Theoretically informed Monte Carlo simulation of liquid crystals by sampling of alignment-tensor fields

Energy Technology Data Exchange (ETDEWEB)

Armas-Pérez, Julio C.; Londono-Hurtado, Alejandro [Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637 (United States); Guzmán, Orlando [Departamento de Física, Universidad Autónoma Metropolitana, Iztapalapa, DF 09340, México (Mexico); Hernández-Ortiz, Juan P. [Departamento de Materiales y Minerales, Universidad Nacional de Colombia, Sede Medellín, Medellín (Colombia); Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637 (United States); Pablo, Juan J. de, E-mail: depablo@uchicago.edu [Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637 (United States); Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2015-07-28

A theoretically informed coarse-grained Monte Carlo method is proposed for studying liquid crystals. The free energy functional of the system is described in the framework of the Landau-de Gennes formalism. The alignment field and its gradients are approximated by finite differences, and the free energy is minimized through a stochastic sampling technique. The validity of the proposed method is established by comparing the results of the proposed approach to those of traditional free energy minimization techniques. Its usefulness is illustrated in the context of three systems, namely, a nematic liquid crystal confined in a slit channel, a nematic liquid crystal droplet, and a chiral liquid crystal in the bulk. It is found that for systems that exhibit multiple metastable morphologies, the proposed Monte Carlo method is generally able to identify lower free energy states that are often missed by traditional approaches. Importantly, the Monte Carlo method identifies such states from random initial configurations, thereby obviating the need for educated initial guesses that can be difficult to formulate.

Theoretically informed Monte Carlo simulation of liquid crystals by sampling of alignment-tensor fields.

Energy Technology Data Exchange (ETDEWEB)

Armas-Perez, Julio C.; Londono-Hurtado, Alejandro; Guzman, Orlando; Hernandez-Ortiz, Juan P.; de Pablo, Juan J.

2015-07-27

A theoretically informed coarse-grained Monte Carlo method is proposed for studying liquid crystals. The free energy functional of the system is described in the framework of the Landau-de Gennes formalism. The alignment field and its gradients are approximated by finite differences, and the free energy is minimized through a stochastic sampling technique. The validity of the proposed method is established by comparing the results of the proposed approach to those of traditional free energy minimization techniques. Its usefulness is illustrated in the context of three systems, namely, a nematic liquid crystal confined in a slit channel, a nematic liquid crystal droplet, and a chiral liquid crystal in the bulk. It is found that for systems that exhibit multiple metastable morphologies, the proposed Monte Carlo method is generally able to identify lower free energy states that are often missed by traditional approaches. Importantly, the Monte Carlo method identifies such states from random initial configurations, thereby obviating the need for educated initial guesses that can be difficult to formulate.

Chirality transfer technique between liquid crystal microdroplets using microfluidic systems

Science.gov (United States)

Guo, Jin-kun; Lee, Doyeon; Song, Jang-kun

2018-02-01

Cholesteric liquid crystal (LC) microdroplet is applied in many areas, such as tunable laser, biosensor, information display and security identification, due to its unique optical properties. The topological structure, defects, and photonic crystallinity in the cholesteric liquid crystal (LC) microdroplet can be controlled through the chirality. Here we report an interesting phenomenon that chirality information can be shared among dispersed LC microdroplets in surfactant aqueous solution, which is driven by the transferring of chiral dopant molecules. As a result, we developed an artificial molecule transfer technology which could in situ vary the material composition within the isolated dispersed microdroplets. The molecular transfer is switchable and the transfer speed is controllable by tuning the molecular solubility in continuous phase. Based on this technique, we manipulated, forward and backward, the topological evolution and the photonic crystal band-gap of the dispersed LC droplet. This technique is an easy and powerful experimental tool, and it may be applicable to other fields in optical application, biology, chemistry and material science.

Smart window using a thermally and optically switchable liquid crystal cell

Science.gov (United States)

Oh, Seung-Won; Kim, Sang-Hyeok; Baek, Jong-Min; Yoon, Tae-Hoon

2018-02-01

Light shutter technologies that can control optical transparency have been studied extensively for developing curtain-free smart windows. We introduce thermally and optically switchable light shutters using LCs doped with push-pull azobenzene, which is known to speed up thermal relaxation. The liquid crystal light shutter can be switched between translucent and transparent states or transparent and opaque states by phase transition through changing temperature or photo-isomerization of doped azobenzene. The liquid crystal light shutter can be used for privacy windows with an initial translucent state or energy-saving windows with an initial transparent state.

Liquid Photonic Crystals for Mesopore Detection.

Science.gov (United States)

Zhu, Biting; Fu, Qianqian; Chen, Ke; Ge, Jianping

2018-01-02

Nitrogen adsorption-desorption for mesopore characterization requires the using of expensive instrumentation, time-consuming processes, and the consumption of liquid nitrogen. Herein, a new method is developed to measure the pore parameters through mixing a mesoporous substance with a supersaturated SiO 2 colloidal solution at different temperatures, and subsequent rapid measurement of reflection changes of the precipitated liquid photonic crystals. The pore volumes and diameters of mesoporous silica were measured according to the positive correlation between unit mass reflection change (Δλ/m) and pore volume (V), and the negative correlation between average absorption temperature (T) and pore diameter (D). This new approach may provide an alternative method for fast, convenient and economical characterization of mesoporous materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Temperature-Frequency Converter Using a Liquid Crystal Cell as a Sensing Element

Directory of Open Access Journals (Sweden)

José Isidro Santos

2012-03-01

Full Text Available A new temperature-frequency converter based on the variation of the dielectric permittivity of the Liquid Crystal (LC material with temperature has been demonstrated. Unlike other temperature sensors based on liquid crystal processing optical signals for determining the temperature, this work presents a system that is able to sense temperature by using only electrical signals. The variation of the dielectric permittivity with temperature is used to modify the capacitance of a plain capacitor using a LC material as non-ideal dielectric. An electric oscillator with an output frequency depending on variable capacitance made of a twisted-nematic (TN liquid crystal (LC cell has been built. The output frequency is related to the temperature of LC cell through the equations associated to the oscillator circuit. The experimental results show excellent temperature sensitivity, with a variation of 0.40% of the initial frequency per degree Celsius in the temperature range from −6 °C to 110 °C.

Molecular reorientation of dye doped nematic liquid crystals in the laser illumination

International Nuclear Information System (INIS)

San, S. E.; Koeysal, O.; Ecevit, F. N.

2002-01-01

In this study it is investigated how dye doped nematic liquid crystals reorient under the illumination of laser beam whose wavelength is appropriate to absorbance characteristics of the doping dye. Nematic liquid crystal E7 is used with anthraquinone dye 1% wt/wt in the preparation of the sample and this material is filled in homegenously aligned measurement cell having 15 μm thickness. Mechanism of molecular reorientation includes the absorbance effects of the energy of laser by doping dye and this reorientation causes the refractive index of the material to be changed. There are potential application possibilities of such molecular reorientation based effects in nonlinear optics such as real time holography whose basis is grating diffraction that is observed and investigated in the frame of fundamentals of molecule light interaction mechanisms. Experimental analyses allowed finding characteristic values of diffraction signals depending on physical parameters of set up for a dye doped liquid crystal system and this system provided a 20 % diffraction efficiency under the optimum circumstances

Progress in linear optics, non-linear optics and surface alignment of liquid crystals

Science.gov (United States)

Ong, H. L.; Meyer, R. B.; Hurd, A. J.; Karn, A. J.; Arakelian, S. M.; Shen, Y. R.; Sanda, P. N.; Dove, D. B.; Jansen, S. A.; Hoffmann, R.

We first discuss the progress in linear optics, in particular, the formulation and application of geometrical-optics approximation and its generalization. We then discuss the progress in non-linear optics, in particular, the enhancement of a first-order Freedericksz transition and intrinsic optical bistability in homeotropic and parallel oriented nematic liquid crystal cells. Finally, we discuss the liquid crystal alignment and surface effects on field-induced Freedericksz transition.

Liquid crystal-based hydrophone arrays

Science.gov (United States)

Brodzeli, Zourab; Silvestri, Leonardo; Michie, Andrew; Chigrinov, Vladimir G.; Guo, Qi; Pozhidaev, Eugene P.; Kiselev, Alexei D.; Ladouceur, Francois

2012-09-01

We describe a fiber optic hydrophone array system that could be used for underwater acoustic surveillance applications (e.g. military, counter terrorist, and customs authorities in protecting ports and harbors), offshore production facilities or coastal approaches as well as various marine applications. In this paper, we propose a new approach to underwater sonar systems using the voltage-controlled liquid crystals and simple multiplexing method. The proposed method permits measurement of sound under water at multiple points along an optical fiber using the low cost components and standard single mode fiber, without complex interferometric measurement techniques, electronics or demodulation software.

Modeling Textural Processes during Self-Assembly of Plant-Based Chiral-Nematic Liquid Crystals

Directory of Open Access Journals (Sweden)