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Sample records for crystal lc alignment

  1. Photosensitive Polymers for Liquid Crystal Alignment

    Science.gov (United States)

    Mahilny, U. V.; Stankevich, A. I.; Trofimova, A. V.; Muravsky, A. A.; Murauski, A. A.

    The peculiarities of alignment of liquid crystal (LC) materials by the layers of photocrosslinkable polymers with side benzaldehyde groups are considered. The investigation of mechanism of photostimulated alignment by rubbed benzaldehyde layer is performed. The methods of creation of multidomain aligning layers on the basis of photostimulated rubbing alignment are described.

  2. Order parameters of liquid crystal on the rubbing surfaces of alignment layers

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Liquid crystal (LC) alignment is most important in LC devices. In this paper, we quantitatively analyze the LC scalar order parameters on the rubbed surface of an alignment layer. Careful measurement of dichroic infrared absorbance is performed. The result gives the evidence that the order parameter of LC just on the rubbed alignment film is only 1/3-1/2 that in the LC bulk.

  3. Liquid Crystal Microlens Using Nanoparticle-Induced Vertical Alignment

    Directory of Open Access Journals (Sweden)

    Shug-June Hwang

    2015-01-01

    Full Text Available The nanoparticle-induced vertical alignment (NIVA of the nematic liquid crystals (LC is applied to achieve an adaptive flat LC microlens with hybrid-aligned nematic (HAN mode by dropping polyhedral oligomeric silsesquioxane (POSS nanoparticle solution on a homogeneous alignment layer. The vertical alignment induced by the POSS nanoparticles resulted in the formation of a hybrid-aligned LC layer with concentric nonuniform distribution of the refractive index in the planar LC cell, which subsequently played the role of the lens, even in the absence of any applied voltages. The dimensions of the concentric HAN structure significantly depend on the volume of the microdroplet and the POSS concentration. The focus effect of this flat microlens was observed while electrically controlling its focal length using the applied voltages from −50 mm to −90 mm.

  4. Polarization Raman Microscopic Study of Molecular Alignment Behavior in Liquid Crystal/Polymer Composite Films

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2005-12-01

    We clarified that the molecular alignment of aggregated polymers is partially synchronized with liquid crystal (LC) director reorientation in an LC/polymer composite film. The molecular alignment behavior in composite films with LC- and polymer-rich regions formed by photopolymerization-induced phase separation was investigated using polarization Raman spectral microscopy. Raman scattering intensity induced by aligned side chains of polymers in the LC-rich region changed with LC director reorientation when voltage was applied to the composite film. It was confirmed for the first time that polymers capable of movement are formed in the LC-rich region.

  5. Switching of polymer-stabilized vertical alignment liquid crystal cell.

    Science.gov (United States)

    Huang, Chi-Yen; Jhuang, Wen-Yi; Hsieh, Chia-Ting

    2008-03-17

    This work investigates the switching characteristics of the polymer-stabilized vertical alignment (VA) liquid crystal (LC) cell. The experimental results reveal that the fall time of the cell declines as the monomer concentration increases because the vertically-aligned polymer networks accelerate the relaxation of the LC molecules. Furthermore, the formed polymer networks impede the growth and annihilation of LC defects, suppressing the optical bounce in the time dependent transmittance curve of the cell when the voltage is applied to the cell, substantially reducing the rise time of the cell. A step-voltage driving scheme is demonstrated to eliminate completely the optical bounce and hence improve further the rise time of the VA LC cell. The rise times of the pristine and the polymer-stabilized VA LC cells under the step-voltage driving scheme are less than 50% of those under the conventional driving scheme.

  6. Photo polymerization-induced vertical phase separation and homeotropic alignment in liquid crystal and polymer mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hyo [Samsung Advanced Institute of Technology, Yongin (Korea, Republic of); Joo, Sangwoo; Kang, Daeseung [Soongsil Univ., Seoul (Korea, Republic of)

    2012-04-15

    We presented a novel method for the homeotropic alignment of LC by using the irradiation of UV light on the LC/NOA65 mixture cell, in which the photo-initiated-polymerization-induced phase separation lowers the surface energy. When the amount of polymer content is sufficiently small, the gravel and network patterns were formed at the substrates via the vertical phase separation. We found that surface roughness plays an important role in the formation of the homeotropic alignment of LC. We also observed the alignment transition of the cells by varying the mixing ratio of LC/NOA65 or the UV radiation time. Furthermore, the present proposed method has great potential for application in display devices. For decades, studies on the alignment of liquid crystal (LC) molecules have been of significant interest due to their immediate applications for display devices and the intriguing physiochemical properties they exhibit at the surface of mixtures. Usually, homeotropic (or vertical) alignment, in which the long axes of the LC molecules are oriented in a direction perpendicular to the surface, is achieved by using surfactants such as lecithin, silanes or polyimide. Recently homeotropic alignment of liquid crystal molecules was achieved by irradiating photosensitive polymers, by doping nanoparticles into LC, by utilizing nano/micro patterns, or by incorporating self-assembled monolayers (SAMs). However, a clear understanding about the alignment mechanism is still elusive. In this paper, we report a novel method for homeotropic alignment of LC by utilizing the phase separation of LC/polymer mixtures.

  7. Liquid Crystal Alignment Control Using Polymer Filament and Polymer Layers Coated on Substrates

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2005-04-01

    We investigated liquid crystal (LC) alignment in LC cells containing an aligned cellulose filament sandwiched by thin polymer layers coated on substrates. Three types of polymer material, namely polystyrene (PS), polyvinyl alcohol (PVA) and polyimide (PI), were used as polymer layers. LC alignment areas induced on both sides of the filament were large in the order of PS, PVA and PI. In the case of the PS layer, the average LC alignment area reached approximately 100 μm in the direction perpendicular to the polymer filament. The molecular interaction between the LC and the PS layer is thought to be weak and it does not disturb the LC alignment due to the polymer filament. On the other hand, rubbed PS layers were used as polymer layers of the LC cell, where the LC alignment direction induced by the rubbed PS layer was perpendicular to the polymer filament. It was found that the LC alignment near the polymer filament gradually bent in the cell plane. The result suggests that various three-dimensional LC alignments can be realized by the combination of the polymer filament and substrate surface.

  8. Liquid crystal alignment on ZnO nanostructure films

    Science.gov (United States)

    Chung, Yueh-Feng; Chen, Mu-Zhe; Yang, Sheng-Hsiung; Jeng, Shie-Chang

    2016-03-01

    The study of liquid crystal (LC) alignment is important for fundamental researches and industrial applications. The tunable pretilt angles of liquid crystal (LC) molecules aligned on the inorganic zinc oxide (ZnO) nanostructure films with controllable surface wettability are demonstrated in this work. The ZnO nanostructure films are deposited on the ITO- glass substrates by the two-steps hydrothermal process, and their wettability can be modified by annealing. Our experimental results show that the pretilt angles of LCs on ZnO nanostructure films can be successfully adjusted over a wide range from ~90° to ~0° as the surface energy on the ZnO nanostructure films changes from ~30 to ~70 mJ/m. Finally we have applied this technique to fabricate a no-bias optically-compensated bend (OCB) LCD with ZnO nanostructure films annealed at 235 °C.

  9. Cinnamate-functionalized hyperbranched polymer as liquid crystal photo-alignment layer

    Institute of Scientific and Technical Information of China (English)

    Bin Jun Shen; Zheng Xie; Ya Ning He; Yan Qing Lian

    2008-01-01

    In this work, 4-methoxylcirmamoyl chloride was reacted with a commercial hyperbranched polymer (Boltom~TM H30) to prepare a hyperbranched photosensitive polymer (H30-Ci). The polymer was characterized by UV absorption spectrum and 1H-NMR spectrum. After processed by Linearly Polarized Polymerization (LPP) method, the spin-coated films of H30-Ci were used as photo-alignment layers to assemble liquid crystal (LC) cells containing nematic liquid crystal (5CB). The observation by polarized microscope showed that the H30-Ci blended with a linear polymer (BP-AN-Ci) photo-alignment layers could align LC molecules in a very uniform way.

  10. Nematic Liquid Crystal Alignment Behaviors between Crossed Stretched Miropolymer Filaments with Anchoring Effects

    Science.gov (United States)

    Fujikake, Hideo; Murashige, Takeshi; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2006-04-01

    We observed the molecular alignment of a liquid crystal (LC) induced by crossing two stretched micropolymer filaments between glass substrates and confirmed its light modulation property. The two microfilaments, which were extracted from a cellulose cloth by stretching it in advance, had surface molecular alignment and stabilized nematic LC alignment between the microfilaments crossed with a small angle. In the fabricated LC cell, a spatially-uniform LC planar alignment is achieved in the area of a filament interval of less than 60 μm. By polarizing microscopy observation of the isotropic-to-nematic wetting transition of the LC material between the polymer filaments, it was confirmed that the stable LC alignment area is formed by the surface anchoring of the filaments. When external voltages were applied to the obtained uniformed alignment LC area, a characteristic periodic electrooptic property was confirmed on the basis of electrically-controlled birefringence under the alignment control of the in-plane anchoring of the filaments.

  11. Bistable liquid crystal device fabricated via microscale liquid crystal alignment

    Science.gov (United States)

    Honma, Michinori; Toyoshima, Wataru; Nose, Toshiaki

    2016-10-01

    Bistable liquid crystal (LC) molecular orientation properties in micropatterned LC cells were investigated experimentally and theoretically. When an LC cell was heated to the phase-transition temperature and then cooled, an LC orientation with ±π/2-twist domains (±π/2-twist mode) was obtained. Furthermore, a different LC orientation with ±π-twist domains (±π-twist mode) was observed when a 10-V potential was applied across a sample LC cell. Both orientation states were stably retained over a long period. Herein, cross-sectional LC orientation models in the ±π/2- and ±π-twist modes are proposed to explain the generation and behavior of two different disclination lines. The total energies within one period in the ±π/2- and ±π-twist modes (F±π/2 and F±π, respectively) were estimated theoretically. These energies were found to depend on the LC layer thickness and to cross over at a certain thickness; this indicates that F±π is equal to F±π/2 at this equilibrium thickness. The best temporal stability is likely attained at this equilibrium thickness. We demonstrated a bistable color-switching device by combining a full-wave plate and crossed polarizers. When these optical components were configured properly, stable bistable switching between two colors was achieved.

  12. Single crystalline growth of a soluble organic semiconductor in a parallel aligned liquid crystal solvent using rubbing-treated polyimide films

    Science.gov (United States)

    Matsuzaki, Tomoya; Shibata, Yosei; Takeda, Risa; Ishinabe, Takahiro; Fujikake, Hideo

    2017-01-01

    For directional control of organic single crystals, we propose a crystal growth method using liquid crystal as the solvent. In this study, we examined the formation of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) single crystals using a parallel aligned liquid crystal (LC) cell and rubbing-treated polyimide films in order to clarify the effects of LC alignment on anisotropic C8-BTBT crystal growth. Based on the results, we found that the crystal growth direction of C8-BTBT single crystals was related to the direction of the aligned LC molecules because of rubbing treatment. Moreover, by optical evaluation, we found that the C8-BTBT single crystals have a aligned molecular structure.

  13. Critical assessment of alignment procedures for LC-MS proteomics and metabolomics measurements

    Directory of Open Access Journals (Sweden)

    Neumann Steffen

    2008-09-01

    Full Text Available Abstract Background Liquid chromatography coupled to mass spectrometry (LC-MS has become a prominent tool for the analysis of complex proteomics and metabolomics samples. In many applications multiple LC-MS measurements need to be compared, e. g. to improve reliability or to combine results from different samples in a statistical comparative analysis. As in all physical experiments, LC-MS data are affected by uncertainties, and variability of retention time is encountered in all data sets. It is therefore necessary to estimate and correct the underlying distortions of the retention time axis to search for corresponding compounds in different samples. To this end, a variety of so-called LC-MS map alignment algorithms have been developed during the last four years. Most of these approaches are well documented, but they are usually evaluated on very specific samples only. So far, no publication has been assessing different alignment algorithms using a standard LC-MS sample along with commonly used quality criteria. Results We propose two LC-MS proteomics as well as two LC-MS metabolomics data sets that represent typical alignment scenarios. Furthermore, we introduce a new quality measure for the evaluation of LC-MS alignment algorithms. Using the four data sets to compare six freely available alignment algorithms proposed for the alignment of metabolomics and proteomics LC-MS measurements, we found significant differences with respect to alignment quality, running time, and usability in general. Conclusion The multitude of available alignment methods necessitates the generation of standard data sets and quality measures that allow users as well as developers to benchmark and compare their map alignment tools on a fair basis. Our study represents a first step in this direction. Currently, the installation and evaluation of the "correct" parameter settings can be quite a time-consuming task, and the success of a particular method is still highly

  14. Photoresponsive carbohydrate-based giant surfactants: automatic vertical alignment of nematic liquid crystal for the remote-controllable optical device.

    Science.gov (United States)

    Kim, Dae-Yoon; Lee, Sang-A; Kang, Dong-Gue; Park, Minwook; Choi, Yu-Jin; Jeong, Kwang-Un

    2015-03-25

    Photoresponsive carbohydrate-based giant surfactants (abbreviated as CELAnD-OH) were specifically designed and synthesized for the automatic vertical alignment (VA) layer of nematic (N) liquid crystal (LC), which can be applied for the fabrication of remote-controllable optical devices. Without the conventional polymer-based LC alignment process, a perfect VA layer was automatically constructed by directly adding the 0.1 wt % CELA1D-OH in the N-LC media. The programmed CELA1D-OH giant surfactants in the N-LC media gradually diffused onto the substrates of LC cell and self-assembled to the expanded monolayer structure, which can provide enough empty spaces for N-LC molecules to crawl into the empty zones for the construction of VA layer. On the other hand, the CELA3D-OH giant surfactants forming the condensed monolayer structure on the substrates exhibited a planar alignment (PA) rather than a VA. Upon tuning the wavelength of light, the N-LC alignments were reversibly switched between VA and PA in the remote-controllable LC optical devices. Based on the experimental results, it was realized that understanding the interactions between N-LC molecules and amphiphilic giant surfactants is critical to design the suitable materials for the automatic LC alignment.

  15. A NEW METHOD TO ALIGN LIQUID CRYSTAL MOLECULES BY LINEAR PHOTO-POLYMERIZATION FOR LIQUID CRYSTAL DISPLAY

    Institute of Scientific and Technical Information of China (English)

    LIANG ZHAO-YAN; FANG KUN; XUAN LI; HUANG XI-MIN; DING BAO-QUAN; LU RAN; ZHAO YING-YING

    2000-01-01

    A new technique to uniformly align liquid crystal molecules is presented.The technique is based on producing an anisotropic surface on the glass substrate coated with photo-polymers by photo-polymerization of linear polarized UVlight.The orientation of liquid crystal molecules is governed by the direction of the polarized vector of UV-light.Using this method,we have studied the photo-polymer PSi-CM aligning LC 6710A molecules.The liquid crystal microscopic texture between crossed polarizers,optical retardation from liquid crystal layers and electro-optical properties of twisted nematic liquid crystal display cell are obtained,which was prepared with one side -photo-alignment and the other siderebbed substrate.

  16. Enhanced contrast ratio of homogeneously aligned liquid crystal displays by controlling the surface-anchoring strength

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Young Jin; Woo, Chang Woo; Oh, Sang Hoon; Mukherjee, Amrita; Lee, Seung Hee [Department of BIN Fusion Technology and Department of Polymer Nano-Science and Technology, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Baek, Ji Ho; Kim, Kyeong Jin; Yang, Myung Su, E-mail: lsh1@chonbuk.ac.kr [Panel Performance Department, LG Display Co., Ltd., Paju, Gyeonggi-do 413-811 (Korea, Republic of)

    2011-08-17

    The dark state of homogeneously aligned liquid crystal displays (LCDs) associated with the in-plane switching of a LC director depends on their molecular ordering. We propose a new approach to reduce the light leakage in the dark state of homogeneously aligned LCDs. A very small amount of reactive mesogen (RM) is mixed with the LC material and polymerized at room temperature and also at a low temperature (-20 {sup 0}C) to strengthen the surface-anchoring energy. The contrast ratio of the low-temperature cured cell is improved by about 50% over that of the pure LC cell and the room temperature cured RM-mixed LC cell due to an enhanced order parameter.

  17. Novel switching mode in a vertically aligned liquid crystal contact lens.

    Science.gov (United States)

    Syed, Ishtiaque M; Kaur, Sarabjot; Milton, Harry E; Mistry, Devesh; Bailey, James; Morgan, Philip B; Jones, J Cliff; Gleeson, Helen F

    2015-04-20

    Liquid crystal (LC) contact lenses are emerging as an exciting technology for vision correction. A homeotropically (vertical) aligned LC lens is reported that offers improved optical quality and simplified construction techniques over previously reported LC contact lens designs. The lens has no polarization dependence in the off state and produces a continuous change in optical power of up to 2.00 ± 0.25 D with a voltage applied. The variation in optical power results from the voltage-induced change in refractive index of the nematic LC layer, from 1.52 to a maximum of 1.72. One device substrate is treated with an alignment layer that is a mixture of planar and homeotropic polyimides, rubbed to induce a preferred director orientation in the switched state. Defects that could occur during switching are thus avoided and the lens exhibits excellent optical quality with a continuous variation in focal power.

  18. In-Plane Switching Mode for Liquid Crystal Displays Using a DNA Alignment Layer.

    Science.gov (United States)

    Cha, Yun Jeong; Gim, Min-Jun; Oh, Kyunghwan; Yoon, Dong Ki

    2015-06-24

    We successfully fabricated the in-plane switching mode (IPS) LC display (LCD) based on a double stranded DNA (dsDNA) alignment layer. As widely known, the DNA has the right-handed double helical structure that has naturally grown grooves with a very regular period, which can be used as an alignment layer to control the orientation of liquid crystal (LC) molecules. The LC molecules on this topographical layer of DNA material align obliquely at a specific angle with respect to the direction of DNA chains, providing an instant and convenient tool for the fabrication of the IPS display compared to the conventional ways such as rubbing and mechanical shearing methods. The electro-optical performance and response time of this device were also investigated. Our result will be of great use in further exploration of the electro-optical properties of the other biomaterials.

  19. Fast Switching of Vertical Alignment Liquid Crystal Cells with Liquid Crystalline Polymer Networks

    Science.gov (United States)

    Baek, Jong-In; Kim, Ki-Han; Kim, Jae Chang; Yoon, Tae-Hoon; Woo, Hwa Sung; Shin, Sung Tae; Souk, Jun Hyung

    2009-05-01

    This paper reports on the electro-optic characteristics of vertical alignment (VA) liquid crystal (LC) cells with liquid crystalline polymer networks. Optical bouncing, that occurs during the turn-on of VA cells, can be eliminated by introducing in-cell polymer networks. Furthermore, the turn-off also becomes much faster because of the anchoring effect caused by the anisotropy in the molecular shape of the liquid crystalline polymers. These response times have been found to vary for different LC/prepolymer mixtures. When the concentration of the liquid crystalline prepolymer in the initial LC/prepolymer mixture was 3, 5, or 10 wt %, the response times were measured to be 34, 56, and 87% faster than those of a VA cell with pure LC. These switching behaviors of VA cells with liquid crystalline polymer networks are demonstrated and compared with those using pure LC and with polymer networks made of isotropic prepolymers.

  20. Alignment and temperature effects in liquid-crystal-based active polarimetry.

    Science.gov (United States)

    Gladish, James C; Duncan, Donald D

    2014-06-20

    It is well known that in liquid crystal (LC)-based active polarimetry, alignment and temperature effects impact polarimeter performance. Practically speaking, when constructing a polarimetric measurement system from LC variable retarders (LCVRs), unavoidable alignment and temperature uncertainties will occur, leading to systematic error that propagates to the Mueller matrix. Typical calibration methods use only a single metric to assess polarimeter performance (the condition number) and often ignore the relationship between systematic error and specific Mueller matrix elements. Here we explore alignment and temperature effects in a Stokes generator and polarimeter, each consisting of two LCVRs, through a series of simulations to calibrate the polarimeter and measure the Mueller matrix of air. We achieve this by modifying an existing LCVR model to incorporate alignment and temperature effects. This new approach offers insight into employing LCVRs individually and associating particular Mueller matrix element error with specific LCVR effects.

  1. Horizontally-aligned carbon nanotubes arrays and their interactions with liquid crystal molecules: Physical characteristics and display applications

    Directory of Open Access Journals (Sweden)

    Frédérick Roussel

    2012-03-01

    Full Text Available We report on the physical characteristics of horizonthally-grown Single-Walled Carbon Nanotubes (h-al-SWNT arrays and their potential use as transparent and conducting alignment layer for liquid crystals display devices. Microscopy (SEM and AFM, spectroscopic (Raman and electrical investigations demonstrate the strong anisotropy of h-al-SWNT arrays. Optical measurements show that h-al-SWNTs are efficient alignment layers for Liquid Crystal (LC molecules allowing the fabrication of optical wave plates. Interactions between h-al-SWNT arrays and LC molecules are also investigated evidencing the weak azimuthal anchoring energy at the interface, which, in turn, leads to LC devices with a high pretilt angle. The electro-optical reponses of h-al-SWNT/LC cells demonstrate that h-al-SWNT arrays are efficient nanostructured electrodes with potential use for the combined replacement of Indium Tin Oxyde and polymeric alignment layers in conventional displays.

  2. MultiAlign: a multiple LC-MS analysis tool for targeted omics analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lamarche, Brian L.; Crowell, Kevin L.; Jaitly, Navdeep; Petyuk, Vladislav A.; Shah, Anuj R.; Polpitiya, Ashoka D.; Sandoval, John D.; Kiebel, Gary R.; Monroe, Matthew E.; Callister, Stephen J.; Metz, Thomas O.; Anderson, Gordon A.; Smith, Richard D.

    2013-02-12

    MultiAlign is a free software tool that aligns multiple liquid chromatography-mass spectrometry datasets to one another by clustering mass and LC elution features across datasets. Applicable to both label-free proteomics and metabolomics comparative analyses, the software can be operated in several modes. Clustered features can be matched to a reference database to identify analytes, used to generate abundance profiles, linked to tandem mass spectra based on parent precursor masses, and culled for targeted liquid chromatography-tandem mass spectrometric analysis. MultiAlign is also capable of tandem mass spectral clustering to describe proteome structure and find similarity in subsequent sample runs.

  3. Synthesis of novel aromatic polyimides containing bulky side chain for vertical alignment liquid crystals

    Institute of Scientific and Technical Information of China (English)

    Jian Wang; Ying Han Wang

    2008-01-01

    In this study, a novel 4-(4-octyloxybenzoyloxy)biphenyl-3',5'-diaminobenzoate and polyimides based on it were synthesized. The polyimide with mesogenic unit side chain exhibited excellent vertical alignment for nematic liquid crystal (LC). The pretilt angles of LCs above 89° were kept after the rubbing process with 220 mm rubbing strength. The polyimide films as the alignment layer were baked at 120℃ for 12 h, the vertical alignment of LCs was still uniform and stable. Meanwhile, the UV-vis spectra of the novel polyimide films showed the high transparency in a visible wave length.

  4. Blazed vector grating liquid crystal cells with photocrosslinkable polymeric alignment films fabricated by one-step polarizer rotation method

    Science.gov (United States)

    Kawai, Kotaro; Kuzuwata, Mitsuru; Sasaki, Tomoyuki; Noda, Kohei; Kawatsuki, Nobuhiro; Ono, Hiroshi

    2014-12-01

    Blazed vector grating liquid crystal (LC) cells, in which the directors of low-molar-mass LCs are antisymmetrically distributed, were fabricated by one-step exposure of an empty glass cell inner-coated with a photocrosslinkable polymer LC (PCLC) to UV light. By adopting a LC cell structure, twisted nematic (TN) and homogeneous (HOMO) alignments were obtained in the blazed vector grating LC cells. Moreover, the diffraction efficiency of the blazed vector grating LC cells was greatly improved by increasing the thickness of the device in comparison with that of a blazed vector grating with a thin film structure obtained in our previous study. In addition, the diffraction efficiency and polarization states of ±1st-order diffracted beams from the resultant blazed vector grating LC cells were controlled by designing a blazed pattern in the alignment films, and these diffraction properties were well explained on the basis of Jones calculus and the elastic continuum theory of nematic LCs.

  5. 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...

  6. Profile-Based LC-MS data alignment--a Bayesian approach.

    Science.gov (United States)

    Tsai, Tsung-Heng; Tadesse, Mahlet G; Wang, Yue; Ressom, Habtom W

    2013-01-01

    A Bayesian alignment model (BAM) is proposed for alignment of liquid chromatography-mass spectrometry (LC-MS) data. BAM belongs to the category of profile-based approaches, which are composed of two major components: a prototype function and a set of mapping functions. Appropriate estimation of these functions is crucial for good alignment results. BAM uses Markov chain Monte Carlo (MCMC) methods to draw inference on the model parameters and improves on existing MCMC-based alignment methods through 1) the implementation of an efficient MCMC sampler and 2) an adaptive selection of knots. A block Metropolis-Hastings algorithm that mitigates the problem of the MCMC sampler getting stuck at local modes of the posterior distribution is used for the update of the mapping function coefficients. In addition, a stochastic search variable selection (SSVS) methodology is used to determine the number and positions of knots. We applied BAM to a simulated data set, an LC-MS proteomic data set, and two LC-MS metabolomic data sets, and compared its performance with the Bayesian hierarchical curve registration (BHCR) model, the dynamic time-warping (DTW) model, and the continuous profile model (CPM). The advantage of applying appropriate profile-based retention time correction prior to performing a feature-based approach is also demonstrated through the metabolomic data sets.

  7. Strengthened nonlinearity in liquid crystal panel with ZnSe aligning layers due to surface charge accumulation

    Science.gov (United States)

    Zhao, Hua; Xue, Tingyu; Fu, Jiayin; Zhang, Jingwen

    2015-09-01

    With ZnSe thin films as aligning layers in fabricating liquid crystal (LC) panel with pentylcyanobiphenyl doped with C60, the response time in writing holograms was shortened to milliseconds. When two laser beams were overlapped in an LC panel, 2D diffraction patterns were observed, along with exponential gain coefficient highly LC and ZnSe thickness dependent. In addition, energy transferring in subwavelength scale through surface grating was evident. By using a hybrid LC panel, it was found the energy transferring direction was voltage polarity and thickness dependent. Electrostatic modification based surface plasmon polariton excitation was proposed to explain all the findings

  8. Liquid crystal alignment in nanoporous anodic aluminum oxide layer for LCD panel applications.

    Science.gov (United States)

    Hong, Chitsung; Tang, Tsung-Ta; Hung, Chi-Yu; Pan, Ru-Pin; Fang, Weileun

    2010-07-16

    This paper reports the implementation and integration of a self-assembled nanoporous anodic aluminum oxide (np-AAO) film and liquid crystal (LC) on an ITO-glass substrate for liquid crystal display (LCD) panel applications. An np-AAO layer with a nanopore array acts as the vertical alignment layer to easily and uniformly align the LC molecules. Moreover, the np-AAO nanoalignment layer provides outstanding material properties, such as being inorganic with good transmittance, and colorless on ITO-glass substrates. In this application, an LCD panel, with the LC on the np-AAO nanoalignment layer, is successfully implemented on an ITO-glass substrate, and its performance is demonstrated. The measurements show that the LCD panel, consisting of an ITO-glass substrate and an np-AAO layer, has a transmittance of 60-80%. In addition, the LCD panel switches from a black state to a bright state at 3 V(rms), with a response time of 62.5 ms. In summary, this paper demonstrates the alignment of LC on an np-AAO layer for LCD applications.

  9. Liquid crystal terahertz phase shifters with functional indium-tin-oxide nanostructures for biasing and alignment

    Science.gov (United States)

    Yang, Chan-Shan; Tang, Tsung-Ta; Pan, Ru-Pin; Yu, Peichen; Pan, Ci-Ling

    2014-04-01

    Indium Tin Oxide (ITO) nanowhiskers (NWhs) obliquely evaporated by electron-beam glancing-angle deposition can serve simultaneously as transparent electrodes and alignment layer for liquid crystal (LC) devices in the terahertz (THz) frequency range. To demonstrate, we constructed a THz LC phase shifter with ITO NWhs. Phase shift exceeding π/2 at 1.0 THz was achieved in a ˜517 μm-thick cell. The phase shifter exhibits high transmittance (˜78%). The driving voltage required for quarter-wave operation is as low as 5.66 V (rms), compatible with complementary metal-oxide-semiconductor (CMOS) and thin-film transistor (TFT) technologies.

  10. Direct induction of molecular alignment in liquid crystal polymer network film by photopolymerization

    Science.gov (United States)

    Hisano, K.; Aizawa, M.; Ishizu, M.; Kurata, Y.; Shishido, A.

    2016-09-01

    Liquid crystal (LC) is the promising material for the fabrication of high-performance soft, flexible devices. The fascinating and useful properties arise from their cooperative effect that inherently allows the macroscopic integration and control of molecular alignment through various external stimuli. To date, light-matter interaction is the most attractive stimuli and researchers developed photoalignment through photochemical or photophysical reactions triggered by linearly polarized light. Here we show the new choice based on molecular diffusion by photopolymerization. We found that photopolymerization of a LC monomer and a crosslinker through a photomask enables to direct molecular alignment in the resultant LC polymer network film. The key generating the molecular alignment is molecular diffusion due to the difference of chemical potentials between irradiated and unirradiated regions. This concept is applicable to various shapes of photomask and two-dimensional molecular alignments can be fabricated depending on the spatial design of photomask. By virtue of the inherent versatility of molecular diffusion in materials, the process would shed light on the fabrication of various high-performance flexible materials with molecular alignment having controlled patterns.

  11. Trapping of defect point to improve response time via controlled azimuthal anchoring in a vertically aligned liquid crystal cell with polymer wall

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Gyun; Kim, Sung Min; Kim, Youn Sik; Lee, Hee Kyu; Lee, Seung Hee [Polymer BIN Fusion Research Center, School of Advanced Materials Engineering, Chonbuk National University, Chonju, Chonbuk 561-756 (Korea, Republic of); Lyu, Jae-Jin; Kim, Kyeong Hyeon [AMLCD Division, Samsung Electronics, Kiheung, Kyunggi-Do 449-711 (Korea, Republic of); Lu, Ruibo; Wu, Shin-Tson [College of Optics and Photonics, University of Central Florida, Orlando FL 32816 (United States)], E-mail: lsh1@chonbuk.ac.kr

    2008-03-07

    Conventional multi-domain vertically aligned liquid crystal (LC) cells have defect points due to the collision of LC directors during the formation of multiple domains. In addition, the location of defects changes with time resulting in a slow response time. This paper proposes a robust vertically aligned LC cell, where the LCs are locked by polymer walls, and the azimuthal anchoring on the surface of the alignment layer is controlled by the polymerization of a UV curable reactive mesogen monomer. As a result, the defect points are trapped at a single position, resulting in a greatly improved response time.

  12. Dielectric relaxation behavior of nematic liquid crystal cell using β-cyclodextrin as an alignment layer

    Directory of Open Access Journals (Sweden)

    Marwa Sahraoui

    2016-02-01

    Full Text Available In the present investigation, we report the dielectric properties of a symmetric Nematic Liquid Crystal (NLC cell using Beta Cyclodextrins (β-CD as alignment layers. These layers were deposited onto Indium Tin Oxide (ITO surface by thermal evaporation and then characterized using contact angle measurement. This revealed a hydrophilic character attributed to the presence of hydroxyl groups. Morphological study was carried out by Scanning Electronic Microscopy (SEM. The dynamic impedance study of the Liquid Crystal (LC cell in a wide frequency range from 1mHz to 13MHz was reported. It was found that the β-CD alignment layer had a blocking effect on the NLC cell at a high frequency range. We also report the relaxation mechanism of NLC cell which is modeled by an appropriate equivalent circuit in order to understand the electrical properties of the liquid crystal cell and to investigate the processes taking place at different interfaces. 

  13. ChromAlign: A two-step algorithmic procedure for time alignment of three-dimensional LC-MS chromatographic surfaces.

    Science.gov (United States)

    Sadygov, Rovshan G; Maroto, Fernando Martin; Hühmer, Andreas F R

    2006-12-15

    We present an algorithmic approach to align three-dimensional chromatographic surfaces of LC-MS data of complex mixture samples. The approach consists of two steps. In the first step, we prealign chromatographic profiles: two-dimensional projections of chromatographic surfaces. This is accomplished by correlation analysis using fast Fourier transforms. In this step, a temporal offset that maximizes the overlap and dot product between two chromatographic profiles is determined. In the second step, the algorithm generates correlation matrix elements between full mass scans of the reference and sample chromatographic surfaces. The temporal offset from the first step indicates a range of the mass scans that are possibly correlated, then the correlation matrix is calculated only for these mass scans. The correlation matrix carries information on highly correlated scans, but it does not itself determine the scan or time alignment. Alignment is determined as a path in the correlation matrix that maximizes the sum of the correlation matrix elements. The computational complexity of the optimal path generation problem is reduced by the use of dynamic programming. The program produces time-aligned surfaces. The use of the temporal offset from the first step in the second step reduces the computation time for generating the correlation matrix and speeds up the process. The algorithm has been implemented in a program, ChromAlign, developed in C++ language for the .NET2 environment in WINDOWS XP. In this work, we demonstrate the applications of ChromAlign to alignment of LC-MS surfaces of several datasets: a mixture of known proteins, samples from digests of surface proteins of T-cells, and samples prepared from digests of cerebrospinal fluid. ChromAlign accurately aligns the LC-MS surfaces we studied. In these examples, we discuss various aspects of the alignment by ChromAlign, such as constant time axis shifts and warping of chromatographic surfaces.

  14. Magnetic Control of MOF Crystal Orientation and Alignment.

    Science.gov (United States)

    Cheng, Fei; Marshall, Ellis S; Young, Adam J; Robinson, Peter J; Bouillard, Jean-Sebastien G; Adawi, Ali M; Vermeulen, Nicolaas A; Farha, Omar K; Reithofer, Michael R; Chin, Jia Min

    2017-09-14

    Most MOFs possess anisotropic properties, the full exploitation of which necessitates a general strategy for the controllable orientation of such MOF crystals. Current methods largely rely upon layer-by-layer MOF epitaxy or tuning of MOF crystal growth on appropriate substrates, yielding MOFs with fixed crystal orientations. Here, the dynamic magnetic alignment of different MOF crystals (NH2-MIL-53(Al) and NU-1000) is shown. The MOFs were magnetized by electrostatic adsorption of iron oxide nanoparticles, dispersed in curable polymer resins (Formlabs 1+ clear resin / Sylgard® 184), magnetically oriented and fixed by resin curing. The importance of crystal orientation on MOF functionality was demonstrated whereby magnetically aligned NU-1000/Sylgard® 184 composite was excited with linearly polarized 405 nm light, affording an anisotropic fluorescence response dependent on the polarization angle of the excitation beam relative to NU-1000 crystal orientation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Mechanism in determining pretilt angle of liquid crystals aligned on fluorinated copolymer films

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hsin-Ying; Wang, Chih-Yu; Lin, Chia-Jen; Pan, Ru-Pin [Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan 30010 (China); Lin, Song-Shiang; Lee, Chein-Dhau [Material and Chemical Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan 31040 (China); Kou, Chwung-Shan, E-mail: rpchao@mail.nctu.edu.t [Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 30013 (China)

    2009-08-07

    This work explores the surface treatment of copolymer materials with fluorinated carbonyl groups in various mole fractions by ultraviolet irradiation and ion-beam (IB) bombardment and its effect on liquid crystal (LC) surface alignments. X-ray photoemission spectroscopic analysis confirms that the content of the grafted CF{sub 2} side chains dominates the pretilt angle. A significant increase in oxygen content is responsible for the increase in the polar surface energy during IB treatment. Finally, the polar component of the surface energy dominates the pretilt angle of the LCs.

  16. Polymer Alignment Behavior with Molecular Switching of Ferroelectric Liquid Crystal

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2007-01-01

    This paper describes the molecular alignment behavior of polymer networks with switching of a ferroelectric liquid crystal (FLC) in a molecularly aligned FLC/polymer composite film. The polymer alignment in the composite film, which was slowly formed by photopolymerization-induced phase separation of a heated nematic-phase solution of FLC and monomers, was observed by polarization Raman spectral microscopy. Raman peak intensities originating from the polymers were changed with those from the FLC, when the applied voltage polarity was changed. The trace patterns of the Raman peak intensity with in-plane rotation of the composite film indicated that the formed flexible polymers can follow FLC molecular switching.

  17. Materials science: Crystals aligned through graphene

    Science.gov (United States)

    Lee, Minjoo Larry

    2017-04-01

    Graphene has been used as a 'transparent' layer that allows single crystals of a material to be grown on a substrate, and then lifted off -- in much the same way that baking paper lets cakes be removed easily from tins. See Letter p.340

  18. Magnetic alignment study of rare-earth-containing liquid crystals.

    Science.gov (United States)

    Galyametdinov, Yury G; Haase, Wolfgang; Goderis, Bart; Moors, Dries; Driesen, Kris; Van Deun, Rik; Binnemans, Koen

    2007-12-20

    The liquid-crystalline rare-earth complexes of the type [Ln(LH)3(DOS)3]-where Ln is Tb, Dy, Ho, Er, Tm, or Yb; LH is the Schiff base N-octadecyl-4-tetradecyloxysalicylaldimine; and DOS is dodecylsulfate-exhibit a smectic A phase. Because of the presence of rare-earth ions with a large magnetic anisotropy, the smectic A phase of these liquid crystals can be easier aligned in an external magnetic field than smectic A phases of conventional liquid crystals. The magnetic anisotropy of the [Ln(LH)3(DOS)3] complexes was determined by measurement of the temperature-dependence of the magnetic susceptibility using a Faraday balance. The highest value for the magnetic anisotropy was found for the dysprosium(III) complex. The magnetic alignment of these liquid crystals was studied by time-resolved synchrotron small-angle X-ray scattering experiments. Depending on the sign of the magnetic anisotropy, the director of the liquid-crystalline molecules was aligned parallel or perpendicular to the magnetic field lines. A positive value of the magnetic anisotropy (and parallel alignment) was found for the thulium(III) and the ytterbium(III) complexes, whereas a negative value of the magnetic anisotropy (and perpendicular alignment) was observed for the terbium(III) and dysprosium(III) complexes.

  19. Alignment of liquid crystal molecules on solution-derived zinc-tin-oxide films via ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hong-Gyu; Jeong, Hae-Chang; Lee, Ju Hwan; Jang, Sang Bok [Information Display Device Laboratory, Department of Electrical and Electronic Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul, 120-749 (Korea, Republic of); Oh, Byeong-Yun [ZeSHTech Co., Ltd., Business Incubator, Gwangju Institute of Science and Technology, 123, Cheomdangwagi-ro, Buk-gu, Gwangju, 500-712 (Korea, Republic of); Han, Jeong-Min [Department of Electronic, Seoil University, Jungnang-gu, Seoul, 131-702 (Korea, Republic of); Seo, Dae-Shik, E-mail: dsseo@yonsei.ac.kr [Information Display Device Laboratory, Department of Electrical and Electronic Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul, 120-749 (Korea, Republic of)

    2016-04-15

    We present the characteristics of annealing temperature-dependent, zinc-tin-oxide (ZTO) films deposited by a solution process for application in liquid crystal displays (LCDs). ZTO surfaces supported homogeneously-aligned liquid crystal (LC) molecules based on an ion beam irradiation system. Uniform LC alignment and a precise pretilt angle were obtained at an annealing temperature greater than 300 °C. The oxidation of ZTO films was confirmed using field-emission-scanning electron microscopy and X-ray photoelectron spectroscopy. The electro-optical characteristics of electrically controlled birefringence (ECB) cells based on the ZTO films were superior to those based on polyimide. Especially, IB-irradiated ZTO films exhibited superior performance with respect to response time. This result indicates that this approach will allow for the fabrication of advanced LCDs with high performance. - Highlights: • ZTO alignment films were deposited by a solution process on ITO-coated glass. • Uniform and homogeneous LC alignment was achieved on the IB-irradiated ZTO surface. • Oxidation of ZTO films was confirmed using FESEM and XPS analysis. • Enhanced EO characteristics of ECB cells based on ZTO films were achieved.

  20. Thin aligned organic polymer films for liquid crystal devices

    CERN Document Server

    Foster, K E

    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.

  1. Effect of the ion-beam bombardment and annealing temperature on sol-gel derived yttrium aluminum oxide film as liquid crystal alignment layer

    Science.gov (United States)

    Jeong, Hae-Chang; Heo, Gi-Seok; Kim, Eun-Mi; Lee, Ju Hwan; Han, Jeong-Min; Seo, Dae-Shik

    2017-02-01

    We demonstrated a homogeneous liquid-crystal (LC) alignment state on yttrium aluminum oxide (YAlO) films, where the alignment was induced by ion-beam (IB) irradiation. Topographical analysis was performed by atomic force microscopy as a function of annealing temperature. Higher annealing temperatures yielded a smoother surface, accompanied by reduced light scattering. Transparency in the visible region increased on the surface fabricated at higher annealing temperatures. LC alignment mechanism was determined by X-ray diffraction (XRD) analysis. Moreover, IB-irradiated YAlO films annealed at temperatures greater than 200 °C exhibited good thermal stability and low capacitance-voltage hysteresis. The IB-irradiated YAlO films are suitable as alternative alignment layers in advanced LC display applications.

  2. Dispersive Stabilization of Liquid Crystal-in-Water with Acrylamide Copolymer/Surfactant Mixture: Nematic Curvilinear Aligned Phase Composite Film.

    Science.gov (United States)

    Park; Lee

    1999-11-01

    The effect of nonionic surfactant, (H(OCH(2)-CH(2))(8)-OC(6)H(4)-C(9)H(19)), on the dispersion stabilization of liquid crystal (LC)-in-water with acrylamide copolymer containing the related nonylphenyl groups was studied. It was observed that the addition of nonionic surfactant increases the stability of LC dispersions and improves the electrooptical properties of the nematic curvilinear aligned phase (NCAP) composite film. On the basis of the surface tension, reduced viscosity, cloud point, and coalescence time measurements, it was proposed that formation of an integrated structure induced by interactions between hydrophobic groups in the polymer chains is probably important to fabrication of a polymer composite film made of LC and polymer matrix. Copyright 1999 Academic Press.

  3. Alignment mechanism of liquid crystal in a stretched porous polymer film

    Science.gov (United States)

    Fujikake, Hideo; Kuboki, Masashi; Murashige, Takeshi; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro

    2003-09-01

    This article discusses the mechanism of nematic liquid crystal alignment in stretched porous polymer films. The polymer films were formed by extreme stretching of an isotropic porous polyolefin, such that the draw ratio was 12:1. A 6-μm-thick porous film with a high porosity coefficient of 92% revealed fine string-shaped areas that exhibited optical anisotropy due to their possessing a high degree of molecular alignment. The porous film was filled with nematic liquid crystal and then the composite film was sandwiched between transparent electrodes coated onto glass substrates, without the use of conventional alignment layers. From polarizing microscopy observations it was found that the string-like polymer areas induce liquid crystal molecular alignment. The liquid crystal cells can exhibit an electrically controlled birefringence effect. This alignment technique enables us to realize three-dimensional control of liquid crystal alignment.

  4. Feedback control of flow alignment in sheared liquid crystals.

    Science.gov (United States)

    Strehober, David A; Schöll, Eckehard; Klapp, Sabine H L

    2013-12-01

    Based on a continuum theory, we investigate the manipulation of the nonequilibrium behavior of a sheared liquid crystal via closed-loop feedback control. Our goal is to stabilize a specific dynamical state, that is, the stationary "flow alignment," under conditions where the uncontrolled system displays oscillatory director dynamics with in-plane symmetry. To this end we employ time-delayed feedback control (TDFC), where the equation of motion for the ith component q(i)(t) of the order parameter tensor is supplemented by a control term involving the difference q(i)(t)-q(i)(t-τ). In this diagonal scheme, τ is the delay time. We demonstrate that the TDFC method successfully stabilizes flow alignment for suitable values of the control strength K and τ; these values are determined by solving an exact eigenvalue equation. Moreover, our results show that only small values of K are needed when the system is sheared from an isotropic equilibrium state, contrary to the case where the equilibrium state is nematic.

  5. Molecular alignment enhancement phenomenon of polymer formed from a liquid crystal monomer in a liquid crystal solvent

    Science.gov (United States)

    Fujikake, Hideo; Murashige, Takeshi; Sato, Hiroto; Kawakita, Masahiro; Kikuchi, Hiroshi

    2003-03-01

    We report an abnormal alignment enhancement phenomenon of polymer molecules. The alignment order of a rigid-skeleton polymer made from a liquid crystalline monomer in a low-molecular-weight liquid crystal solvent was drastically enhanced with increasing temperature, even though the alignment order of the solution of the liquid crystal and monomer decreased. From polymer molecular alignment observations using polarizing Raman scattering microscopy, it was found that the polymer alignment order was three times greater than that of the original aligned monomer and polymer. This super alignment technique of polymer using a molecular-scaled self-assembly mechanism is applicable to the formation of electrically and/or optically functional nanopolymer wires.

  6. LC-MS solvent composition monitoring and chromatography alignment using mobile phase tracer molecules.

    Science.gov (United States)

    Chen, Sharon S; Aebersold, Ruedi

    2005-12-27

    In the field of proteomics, reproducible liquid chromatographic description of analytes is often a key element for the differentiation or identification of proteins or peptides for clinical or biological research projects. However, analyte identification by retention time can be problematic in proteomics where lack of standardization can result in significantly different chromatography for the same analytes analyzed on different machines. Here we present a novel method of monitoring the mobile phase gradient of LC-MS/MS analyses by monitoring the ion current signal intensities of tracer molecules dissolved in the mobile phase solvents. The tracers' ion current signal intensities chronicled gradient fluctuations, did not adversely affect the number or quality of CID-based sequence identifications, and had lower run-to-run variance when compared to retention time.

  7. Olivine crystals align during diffusion creep of Earth's upper mantle.

    Science.gov (United States)

    Miyazaki, Tomonori; Sueyoshi, Kenta; Hiraga, Takehiko

    2013-10-17

    The crystallographic preferred orientation (CPO) of olivine produced during dislocation creep is considered to be the primary cause of elastic anisotropy in Earth's upper mantle and is often used to determine the direction of mantle flow. A fundamental question remains, however, as to whether the alignment of olivine crystals is uniquely produced by dislocation creep. Here we report the development of CPO in iron-free olivine (that is, forsterite) during diffusion creep; the intensity and pattern of CPO depend on temperature and the presence of melt, which control the appearance of crystallographic planes on grain boundaries. Grain boundary sliding on these crystallography-controlled boundaries accommodated by diffusion contributes to grain rotation, resulting in a CPO. We show that strong radial anisotropy is anticipated at temperatures corresponding to depths where melting initiates to depths where strongly anisotropic and low seismic velocities are detected. Conversely, weak anisotropy is anticipated at temperatures corresponding to depths where almost isotropic mantle is found. We propose diffusion creep to be the primary means of mantle flow.

  8. Conformational fluctuations affect protein alignment in dilute liquid crystal media

    DEFF Research Database (Denmark)

    Louhivuori, M.; Otten, R.; Lindorff-Larsen, Kresten

    2006-01-01

    The discovery of dilute liquid crystalline media to align biological macromolecules has opened many new possibilities to study protein and nucleic acid structures by NMR spectroscopy. We inspect the basic alignment phenomenon for an ensemble of protein conformations to deduce relative contributions...... molecular surfaces. Furthermore, we consider the implications of a dynamic bias to structure determination using data from the weak alignment method....

  9. The low cycle fatigue behaviour of as cast single crystal CM186LC

    Energy Technology Data Exchange (ETDEWEB)

    Bale, D.W.; Henderson, M. [ALSTOM Power Technology Centre, Leicestershire (United Kingdom); Dubiel, B.; Czyrska-Filemonowicz, A. [Univ. of Mining and Metallurgy (AGH), Krakow (Poland); Guardamagna, C.; Bontempi, P. [CESI SpA, Milan (Italy); Mulvihill, P. [Powergen, Power Technology Centre, Nottingham (United Kingdom); Lukas, P.; Obrtlik, K. [Academy of Sciences of the Czech Republic, Brno (Czech Republic); Kolkman, H. [National Aerospace Lab., NLR (Netherlands)

    2002-07-01

    CM186 LC DS is well established as a first stage industrial gas turbine (IGT) blade material and has been adopted by leading IGT manufacturers due to significant grain boundary tolerance and cost benefits. To increase the temperature capability, single crystal (SX) casting practices have been applied. The composition and heat treatment are identical to those of the DS variant meaning that the cost savings remain. The following paper characterises the low cycle fatigue (LCF) properties of CM186LC SX, and considers the effects of orientation, temperature, strain rate and mean stress on the cyclic stress-strain and strain-life characteristics. The impact of LCF and creep loading interactions has also been studied by applying tensile and compressive dwell periods during the fatigue cycle. Fractographic and microstructural analysis of as-received and fatigued specimens has been conducted. (orig.)

  10. Versatile alignment layer method for new types of liquid crystal photonic devices

    Energy Technology Data Exchange (ETDEWEB)

    Finnemeyer, V.; Bryant, D.; Lu, L.; Bos, P. [Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 (United States); Reich, R.; Clark, H.; Berry, S.; Bozler, C. [MIT Lincoln Laboratory, 244 Wood St., Lexington, Massachusetts 02420 (United States); Yaroshchuk, O. [Institute of Physics, NAS of Ukraine, 44 Prospect Nauky, Kyiv 03680 (Ukraine)

    2015-07-21

    Liquid crystal photonic devices are becoming increasingly popular. These devices often present a challenge when it comes to creating a robust alignment layer in pre-assembled cells. In this paper, we describe a method of infusing a dye into a microcavity to produce an effective photo-definable alignment layer. However, previous research on such alignment layers has shown that they have limited stability, particularly against subsequent light exposure. As such, we further describe a method of utilizing a pre-polymer, infused into the microcavity along with the liquid crystal, to provide photostability. We demonstrate that the polymer layer, formed under ultraviolet irradiation of liquid crystal cells, has been effectively localized to a thin region near the substrate surface and provides a significant improvement in the photostability of the liquid crystal alignment. This versatile alignment layer method, capable of being utilized in devices from the described microcavities to displays, offers significant promise for new photonics applications.

  11. Phase separation of monomer in liquid crystal mixtures and surface morphology in polymer-stabilized vertical alignment liquid crystal displays

    Energy Technology Data Exchange (ETDEWEB)

    Lyu, Jae Jin; Lee, Jun Hyup; Kim, Kyeong Hyeon [Development Center, LCD Business, SAMSUNG Electronics Co. LTD., Tangjeong-Myeon, Asan, Chungnam 336-741 (Korea, Republic of); Kikuchi, Hirotsuku; Higuchi, Hiroki [Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8580 (Japan); Kim, Dae Hyun; Lee, Seung Hee, E-mail: jsquare.lyu@samsung.com, E-mail: lsh1@chonbuk.ac.kr [Department of BIN Fusion Technology and Department of Polymer-Nano Science and Technology, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of)

    2011-08-17

    The polymer-stabilized vertically aligned (PS-VA) liquid crystal display (LCD) driving mode has high potential for manufacturing low power consuming displays due to the higher transmittance and fast response as compared with the existing patterned vertically aligned and multi-domain vertically aligned modes. In this paper we have investigated the reaction mechanisms of monomer-liquid crystal blends to form a surface pre-tilt angle of liquid crystal in vertical alignment LCD associated with a fishbone electrode structure. The observed sizes of polymer bumps formed on the substrates were found to be dependent on the exposed UV wavelength and were almost equal in both top and bottom substrates. When a large UV wavelength was used, the phase separation mechanism of monomer in PS-VA mode was found nearly isotropic rather than anisotropic in contrast to the previous studies.

  12. 全息光栅液晶排列性质与厚度关系相关的研究%Study on the Alignment Properties and the Thickness of Liquid Crystal on Holographic Grating

    Institute of Scientific and Technical Information of China (English)

    陈兰莉

    2006-01-01

    Using scanning electron microscope and polarizing optical microscope, the author investigates the relationship between the alignment properties of a nematic liquid crystal (LC) and the thickness of the LC layers on a holographic grating. As the thickness of the LC layer (d) increases, the LC alignment properties are found to change dramatically. Unidirectional LC alignment is achieved along the microgrooves only for moderately thick LC layers (1 < d<10 μm), but not for thin (d< 1.0 μm) or thick (d>10 μm) LC layers. The thickness-dependent LC alignment properties are explained in terms of the competitions between the microgroove-introduced physical confinement effect and the embossed-ridge introduced extra surface anchoring effect.%利用电子扫描显微镜和极化光学显微镜,研究了全息光栅液晶向列(LC)排列的性质和厚度之间的关系.研究发现,随着LC厚度的增加,LC排列的性质变化很大.单向的LC不是沿厚度小(d<1.0)或大(d>10μm)的纹沟方向,而是沿着中等厚度(1<d<10μm)的细微纹沟方向排列.这种厚度相关的LC排列性质可以解释为细微纹沟的物理限制效应和额外表面的浮雕脊的锚效应竞争的结果.

  13. Integrated self-aligned tips for dispersion tuning in a photonic crystal micro-cavity

    NARCIS (Netherlands)

    Chakkalakkal Abdulla, S.M.; Kauppinen, L.J.; de Ridder, R.M.; Krijnen, Gijsbertus J.M.

    2011-01-01

    A micro-bimorph cantilever is monolithically integrated with a photonic crystal micro-cavity based device, using surface micro-machining techniques. The integrated cantilever is equipped with self-aligned dielectric tips with respect to the holes of the photonic crystal and on electrostatic

  14. Substrate-induced bulk alignment of liquid crystals

    DEFF Research Database (Denmark)

    Zhang, Zhengping; Chakrabarti, A.; Mouritsen, Ole G.;

    1996-01-01

    The Gay-Berne model for liquid crystals in the presence of a substrate surface is studied using the hybrid Monte Carlo method. A simple non-mean-field substrate-molecule potential is proposed to describe the effects of rubbed polymer-coated substrates on the liquid crystals. Effects...

  15. Measurement of pair-production by high energy photons in an aligned tungsten crystal

    Science.gov (United States)

    Moore, R.; Parker, M. A.; Baurichter, A.; Kirsebom, K.; Medenwaldt, R.; Mikkelsen, U.; Møller, S. P.; Uggerhøj, E.; Worm, T.; Doble, N.; Elsener, K.; Ballestrero, S.; Sona, P.; Strakhovenko, V. M.; Biino, C.; Vilakazi, Z. Z.

    1996-10-01

    A new measurement has been made of the rate of pair-production in a 3.2 mm thick tungsten crystal, exposed to photons with energies in the range 10 to 150 GeV, for angles of incidence up to 10 mrad from the crystal axis. A strong enhancement of the pair-production rate is observed when the beam is aligned along the crystal axis, as compared to a random orientation. This effect can be exploited in the NA48 CP-violation experiment by using a thin crystal rather than an amorphous material to convert photons, thus minimising the scattering of kaons in the converter.

  16. Liquid crystal devices for photonics applications

    Science.gov (United States)

    Chigrinov, Vladimir G.

    2007-11-01

    Liquid crystal (LC) devices for Photonics applications is a hot topic of research. Such elements begin to appear in Photonics market. Passive elements for fiber optical communication systems (DWDM components) based on LC cells can successfully compete with the other elements used for the purpose, such as micro electromechanical (MEM), thermo-optical, opto-mechanical or acousto-optical devices. Application of nematic and ferroelectric LC for high speed communication systems, producing elements that are extremely fast, stable, durable, of low loss, operable over a wide temperature range, and that require small operating voltages and extremely low power consumption. The known LC applications in fiber optics enable to produce switches, filters, attenuators, equalizers, polarization controllers, phase emulators and other fiber optical components. Good robustness due to the absence of moving parts and compatibility with VLSI technology, excellent parameters in a large photonic wavelength range, whereas the complexity of the design and the cost of the device are equivalent to regular passive matrix LC displays makes LC fiber optical devices very attractive for mass production. We have already successfully fabricated certain prototypes of the optical switches based on ferroelectric and nematic LC materials. The electrooptical modes used for the purpose included the light polarization rotation, voltage controllable diffraction and fast switching of the LC refractive index. We used the powerful software to optimize the LC modulation characteristics. Use of photo-alignment technique pioneered by us makes it possible to develop new LC fiber components. Almost all the criteria of perfect LC alignment are met in case of azo-dye layers. We have already used azo-dye materials to align LC in superthin photonic holes, curved and 3D surfaces and as cladding layers in microring silicon based resonators. The prototypes of new LC efficient Photonics devices are envisaged. Controllable

  17. SAXS reveals the magnetic alignment pathway of the goethite columnar liquid crystal phase

    NARCIS (Netherlands)

    Leferink op Reinink, Anke B G M; van den Pol, Esther; Vroege, Gert Jan; Petukhov, Andrei V.

    2014-01-01

    The alignment of board-like colloidal goethite particles in the dense rectangular centred columnar liquid crystal phase in an external magnetic field is studied using small angle X-ray scattering (SAXS). Transient SAXS-patterns show broadening of the columnar reflections in specific directions. Whil

  18. Application of LC-MS and LC-MS-MS to the analysis of photo-decomposed crystal violet in the investigation of cultural heritage materials aging.

    Science.gov (United States)

    Favaro, Gabriella; Confortin, Daria; Pastore, Paolo; Brustolon, Marinarosa

    2012-12-01

    In this work, the accurate liquid chromatography-ultraviolet-visible (LC-UV-Vis), LC-mass spectrometry (MS) and LC-MS-MS analysis of the photo-degradation products of crystal violet (CV) is reported. CV is a light fugitive early synthetic dye which had a widespread diffusion into the market starting from the end of the XIX century and was used among others by V. Van Gogh and P. Gauguin in their writings, drawings or paintings. On-line photodiode array detector enabled simultaneous UV-Vis spectra acquisition. Many degradation compounds were identified through their exact mass (2 ppm accuracy) and MS-MS technique. In particular, all CV demethylated products, demethylated Michler's ketone and particularly some compounds that most likely contain oxygen, such as N-oxides, were found. Fragmentation products are all justified by the proposed fragmentation scheme, in term of precursor exact mass and isotopic profile, characteristic losses in fragmentation and rebuilt structure formula. In particular, we hypothesized the presence of N-imido oxides and hydroxylamine derivates, never reported before, together with the demethylated derivatives of the studied dyes. All these compounds, although at trace level in our samples, contribute to the discoloration and fading of works of arts made with CV. In particular, demethylation of CV by UV light leads to formation of compounds absorbing at shorter wavelengths than CV (blue shift) or no-absorbing in visible range (yellow-colourless) with an overall effect that may appear reddish-brown. This phenomenon justifies drawings appearing grey or brown on aged yellowed paper, when CV-based inks or paints were used. The final aim was to better characterize the photo-degradation of early synthetic dyes (in particular of CV) and to gain a better insight into the discoloration and fading of purple ink strokes made of CV. Copyright © 2012 John Wiley & Sons, Ltd.

  19. Investigation of classical radiation reaction with aligned crystals

    CERN Document Server

    Di Piazza, A; Uggerhøj, Ulrik I

    2015-01-01

    Classical radiation reaction is the effect of the radiation emitted by an accelerated electric charge on the trajectory of the charge itself. The self-consistent underlying classical equation of motion including radiation-reaction effects, the Landau-Lifshitz equation, has never been tested experimentally, in spite of the first theoretical treatments having been developed more than a century ago. Here, we show that classical radiation reaction effects, as predicted by the Landau-Lifshitz equation, can be measured using presently available facilities, in the energy emission spectrum of a parallel $10$-$\\text{GeV}$ electron beam crossing a $1.1$-$\\text{mm}$ thick diamond crystal in the axial channeling regime. Our theoretical results demonstrate the feasibility of the suggested setup, e.g., at the CERN Secondary Beam Areas (SBA) beamlines.

  20. Investigation of classical radiation reaction with aligned crystals

    Directory of Open Access Journals (Sweden)

    A. Di Piazza

    2017-02-01

    Full Text Available Classical radiation reaction is the effect of the electromagnetic field emitted by an accelerated electric charge on the motion of the charge itself. The self-consistent underlying classical equation of motion including radiation–reaction effects, the Landau–Lifshitz equation, has never been tested experimentally, in spite of the first theoretical treatments of radiation reaction having been developed more than a century ago. Here we show that classical radiation reaction effects, in particular those due to the near electromagnetic field, as predicted by the Landau–Lifshitz equation, can be measured in principle using presently available facilities, in the energy emission spectrum of 30-GeV electrons crossing a 0.55-mm thick diamond crystal in the axial channeling regime. Our theoretical results indicate the feasibility of the suggested setup, e.g., at the CERN Secondary Beam Areas (SBA beamlines.

  1. Investigation of classical radiation reaction with aligned crystals

    Science.gov (United States)

    Di Piazza, A.; Wistisen, Tobias N.; Uggerhøj, Ulrik I.

    2017-02-01

    Classical radiation reaction is the effect of the electromagnetic field emitted by an accelerated electric charge on the motion of the charge itself. The self-consistent underlying classical equation of motion including radiation-reaction effects, the Landau-Lifshitz equation, has never been tested experimentally, in spite of the first theoretical treatments of radiation reaction having been developed more than a century ago. Here we show that classical radiation reaction effects, in particular those due to the near electromagnetic field, as predicted by the Landau-Lifshitz equation, can be measured in principle using presently available facilities, in the energy emission spectrum of 30-GeV electrons crossing a 0.55-mm thick diamond crystal in the axial channeling regime. Our theoretical results indicate the feasibility of the suggested setup, e.g., at the CERN Secondary Beam Areas (SBA) beamlines.

  2. A high-throughput processing service for retention time alignment of complex proteomics and metabolomics LC-MS data

    NARCIS (Netherlands)

    Ahmad, Isthiaq; Suits, Frank; Hoekman, Berend; Swertz, Morris A.; Byelas, Heorhiy; Dijkstra, Martijn; Hooft, Rob; Katsubo, Dmitry; van Breukelen, Bas; Bischoff, Rainer; Horvatovich, Peter

    2011-01-01

    Warp2D is a novel time alignment approach, which uses the overlapping peak volume of the reference and sample peak lists to correct misleading peak shifts. Here, we present an easyto- use web interface for high-throughput Warp2D batch processing time alignment service using the Dutch Life Science Gr

  3. Liquid crystal modified photonic crystal fiber (LC-PCF) fabricated with an un-cured SU-8 photoresist sealing technique for electrical flux measurement.

    Science.gov (United States)

    Kuo, Shu-Ming; Huang, Yu-Wen; Yeh, Szu-Ming; Cheng, Wood-Hi; Lin, Che-Hsin

    2011-09-12

    The optical transmission properties of photonic crystal fibers (PCFs) can be manipulated by modifying the pattern arrangement of the air channels within them. This paper presents a novel MEMS-based technique for modifying the optical transmission properties of commercial photonic-crystal fiber (PCF) by selectively filling the voids within the fiber structure with liquid crystals. In the proposed approach, an un-cured SU-8 ring pattern with a thickness of 5 μm is fabricated using a novel stamping method. The PCF is then brought into contact with the SU-8 pattern and an infra-red (IR) laser beam is passed through the fiber in order to soften the SU-8 surface; thereby selectively sealing some of the air channels with molten SU-8. Liquid crystals (LCs) are then infiltrated into the un-sealed holes in the PCF via capillary effects in order to modify the transmission properties of the PCF. Two selectively-filled PCFs are fabricated, namely an inner-ring LC-PCF and a single-line LC-PCF, respectively. It is shown that the two LC-PCFs exhibit significantly different optical behaviors. The practical applicability of the proposed selective-filling approach is demonstrated by fabricating an electric field sensor. The experimental results show that the sensor has the ability to measure electric fields with an intensity of up to 40 kV/cm.

  4. Elimination of off-axis light leakage in a homogeneously aligned liquid crystal cell

    Science.gov (United States)

    Oh, Seung-Won; Park, Byung Wok; Yoon, Tae-Hoon

    2015-03-01

    Among various liquid crystal display modes, the in-plane switching mode exhibits the widest viewing angle because the liquid crystals are homogeneously-aligned initially and rotate within a plane parallel to the substrates when an in-plane field is applied. However, further improvement is still needed for viewing high-quality dark images from the bisector direction of the crossed polarizers. Several compensation schemes have been proposed to eliminate the off-axis light leakage in a homogeneously-aligned liquid crystal cell. Although a 100:1 iso-contrast contour at an wavelength of 550 nm can cover the entire viewing cone, light leakage at other wavelengths still remains very severe. In this paper we introduce achromatic optical compensation methods using uniaxial films to eliminate the off-axis light leakage at the dark state in homogeneously-aligned liquid crystal cell.Uniaxial films with different dispersion characteristics are used so that they can compensate one another to achieve achromatic optical compensation. The retardation values are optimized through numerical research with the aid of the Poincaré sphere.

  5. Integrated crystal mounting and alignment system for high-throughput biological crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Nordmeyer, Robert A.; Snell, Gyorgy P.; Cornell, Earl W.; Kolbe, William; Yegian, Derek; Earnest, Thomas N.; Jaklevic, Joseph M.; Cork, Carl W.; Santarsiero, Bernard D.; Stevens, Raymond C.

    2005-07-19

    A method and apparatus for the transportation, remote and unattended mounting, and visual alignment and monitoring of protein crystals for synchrotron generated x-ray diffraction analysis. The protein samples are maintained at liquid nitrogen temperatures at all times: during shipment, before mounting, mounting, alignment, data acquisition and following removal. The samples must additionally be stably aligned to within a few microns at a point in space. The ability to accurately perform these tasks remotely and automatically leads to a significant increase in sample throughput and reliability for high-volume protein characterization efforts. Since the protein samples are placed in a shipping-compatible layered stack of sample cassettes each holding many samples, a large number of samples can be shipped in a single cryogenic shipping container.

  6. Integrated crystal mounting and alignment system for high-throughput biological crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Nordmeyer, Robert A. (San Leandro, CA); Snell, Gyorgy P. (Richmond, CA); Cornell, Earl W. (Antioch, CA); Kolbe, William F. (Moraga, CA); Yegian, Derek T. (Oakland, CA); Earnest, Thomas N. (Berkeley, CA); Jaklevich, Joseph M. (Lafayette, CA); Cork, Carl W. (Walnut Creek, CA); Santarsiero, Bernard D. (Chicago, IL); Stevens, Raymond C. (La Jolla, CA)

    2007-09-25

    A method and apparatus for the transportation, remote and unattended mounting, and visual alignment and monitoring of protein crystals for synchrotron generated x-ray diffraction analysis. The protein samples are maintained at liquid nitrogen temperatures at all times: during shipment, before mounting, mounting, alignment, data acquisition and following removal. The samples must additionally be stably aligned to within a few microns at a point in space. The ability to accurately perform these tasks remotely and automatically leads to a significant increase in sample throughput and reliability for high-volume protein characterization efforts. Since the protein samples are placed in a shipping-compatible layered stack of sample cassettes each holding many samples, a large number of samples can be shipped in a single cryogenic shipping container.

  7. Theoretical analysis of nanoparticle-induced homeotropic alignment in nematic liquid crystals

    CERN Document Server

    Choudhary, Amit; Li, Guoqiang

    2015-01-01

    A theoretical analysis of homeotropic alignment induced by nanoparticles (NPs) in a nematic liquid crystal (NLC) sample cell is presented. It is found that such alignment on the surface of a NP causes a change in the orientation of the molecular director near the surface, which in turn induces variations in the elastic constants and free energy. The induced NLC properties allow coupling between nearby NPs, mediated by the NLC molecules. The rotation of the coupled NPs close to the substrate tends to induce a long-range orientation of the NLC molecular director, leading to modification in the alignment at the interface of NLC and substrate which induces the orientation from homogeneous (planar) to homeotropic (vertical) in the bulk material.

  8. Anchoring energy enhancement and pretilt angle control of liquid crystal alignment on polymerized surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Weng, Libo; Chien, Liang-Chy [Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 (United States); Liao, Pei-Chun [Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 (United States); AU Optronics Corporation, Hsinchu, 300, Taiwan (China); Lin, Chen-Chun; Ting, Tien-Lun; Hsu, Wen-Hao; Su, Jenn-Jia [AU Optronics Corporation, Hsinchu, 300, Taiwan (China)

    2015-09-15

    We demonstrate enhanced surface anchoring energy and control of pretilt angle in a nematic liquid crystal cell with vertical alignment and polymerized surfaces (PS-VA). The polymerized surfaces are formed by ultraviolet (UV) irradiation-induced phase separation of a minute amount of a reactive monomer in the vertical-aligned nematic liquid crystal. By introducing a bias voltage during UV curing, surface-localized polymer protrusions with a dimension of 100nm and a field-induced pretilt angle are observed. Experimental evidences and theoretical analyses validate that PS-VA has increased surface anchoring strength by two folds and pretilt angle has been changed from 89° to 86° compared to those of a VA cell. The enabling PS-VA cell technique with excel electro-optical properties such as very good dark state, high optical contrast, and fast rise and decay times may lead to development of a wide range of applications.

  9. Anchoring energy enhancement and pretilt angle control of liquid crystal alignment on polymerized surfaces

    Directory of Open Access Journals (Sweden)

    Libo Weng

    2015-09-01

    Full Text Available We demonstrate enhanced surface anchoring energy and control of pretilt angle in a nematic liquid crystal cell with vertical alignment and polymerized surfaces (PS-VA. The polymerized surfaces are formed by ultraviolet (UV irradiation-induced phase separation of a minute amount of a reactive monomer in the vertical-aligned nematic liquid crystal. By introducing a bias voltage during UV curing, surface-localized polymer protrusions with a dimension of 100nm and a field-induced pretilt angle are observed. Experimental evidences and theoretical analyses validate that PS-VA has increased surface anchoring strength by two folds and pretilt angle has been changed from 89° to 86° compared to those of a VA cell. The enabling PS-VA cell technique with excel electro-optical properties such as very good dark state, high optical contrast, and fast rise and decay times may lead to development of a wide range of applications.

  10. Averaged Stokes polarimetry applied to characterize parallel-aligned liquid crystal on silicon displays

    OpenAIRE

    Márquez Ruiz, Andrés; Martínez Guardiola, Francisco Javier; Gallego Rico, Sergi; Ortuño Sánchez, Manuel; Beléndez Vázquez, Augusto; Pascual Villalobos, Inmaculada

    2014-01-01

    Parallel-aligned liquid crystal on silicon (PA-LCoS) displays have become the most attractive spatial light modulator device for a wide range of applications, due to their superior resolution and light efficiency, added to their phase-only capability. Proper characterization of their linear retardance and phase flicker instabilities is a must to obtain an enhanced application of PA-LCoS. We present a novel polarimetric method, based on Stokes polarimetry, we have recently proposed for the mea...

  11. Electrical dependencies of optical modulation capabilities in digitally addressed parallel aligned liquid crystal on silicon devices

    OpenAIRE

    Martínez Guardiola, Francisco Javier; Márquez Ruiz, Andrés; Gallego Rico, Sergi; Ortuño Sánchez, Manuel; Francés Monllor, Jorge; Beléndez Vázquez, Augusto; Pascual Villalobos, Inmaculada

    2014-01-01

    Parallel aligned liquid crystal on silicon (PA-LCoS) displays have found wide acceptance in applications requiring phase-only modulation. Among LCoS devices, and PA-LCoS as a specific case, digital addressing has become a very common technology. In principle, modern digital technology provides some benefits with respect to analog addressing such as reduced interpixel cross-talk, lower power consumption and supply voltage, gray level scale repeatability, high programmability, and noise robustn...

  12. Compounding of hydroxyapatite crystals to molecularly aligned crab tendon chitosan: the effect of heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Atsushi [Creative Research Initiative ' Sousei' , Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan) and Biomaterials Research Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan)]. E-mail: Matsuda.Atsushi@nims.go.jp; Kasahara, Mayumi [School of Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169-0072 (Japan); Kobayashi, Hisatoshi [Biomaterials Research Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan)]. E-mail: Kobayashi.Hisatoshi@nims.go.jp; Ichinose, Noboru [School of Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku-ku, Tokyo 169-0072 (Japan); Tanaka, Junzo [Creative Research Initiative ' Sousei' , Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan); Biomaterials Research Center, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan)

    2004-12-01

    The aim of this study was to demonstrate the effect of heat treatment on the formation of hydroxyapatite crystals in molecularly aligned chitosan. Molecularly aligned chitosan was prepared from crab (Macrocheira Kaempferi) tendons by treatment with ethanol and a 4 wt.% NaOH solution to remove proteins and calcium phosphate, subsequently performed was deacetyl treatment using a 50 wt.% NaOH solution at 100 deg. C. The tendon chitosan (t-chitosan) obtained was compounded with hydroxyapatite (HAp) before and after heat treatment by applying an alternate soaking method. The amount of compounded HAp to t-chitosan before heat treatment was larger than that after heat treatment as shown by thermogravimetric and differential thermal analysis (TG-DTA) analysis. The HAp compounded to t-chitosan before heat treatment was distributed on the whole area as shown by energy dispersive X-ray spectroscopy (EDS) analysis. On the other hand, the compound after heat treatment was distributed only on the surface of t-chitosan. The compounded HAp crystals to t-chitosan before heat treatment were aligned in the horizontal direction to t-chitosan molecules as shown by transmission electron microscopy (TEM) and electron diffraction technique. These results suggest the control of crystallographic orientation in HAp by aligned amino groups.

  13. Solitons and production of defects in flow-aligning nematic liquid crystals under simple shear flow

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The production of defects in flow-aligning nematic liquid crystals under simple shear flow is analyzed by linear stability analysis based on Leslie-Ericksen theory. It is pointed out that the equation of motion of the nematic director under simple shear flow conforms to the driven over-damped sine-Gordon equation and has a soliton solution of amplitude π. It has also been shown that the stationary state with the director uniformly oriented at a Leslie angle is only a metastable state and that the potential, which governs the motion of the director, has infinite numbers of stable stationary states. Therefore, the defects, appearing as a stable solitary solution, can be nucleated from a uniformly aligned flow-aligning type of nematic liquid crystal by shear flow. On the other hand, the bands with long axis parallel to the vorticity axis, appearing as an unstable solution, can be observed as transient patterns at low shear rate and low shear strain value. The theoretical predictions are compared with previous experimental observations.

  14. High-mobility field-effect transistors from large-area solution-grown aligned C60 single crystals.

    Science.gov (United States)

    Li, Hanying; Tee, Benjamin C-K; Cha, Judy J; Cui, Yi; Chung, Jong Won; Lee, Sang Yoon; Bao, Zhenan

    2012-02-08

    Field-effect transistors based on single crystals of organic semiconductors have the highest reported charge carrier mobility among organic materials, demonstrating great potential of organic semiconductors for electronic applications. However, single-crystal devices are difficult to fabricate. One of the biggest challenges is to prepare dense arrays of single crystals over large-area substrates with controlled alignment. Here, we describe a solution processing method to grow large arrays of aligned C(60) single crystals. Our well-aligned C(60) single-crystal needles and ribbons show electron mobility as high as 11 cm(2)V(-1)s(-1) (average mobility: 5.2 ± 2.1 cm(2)V(-1)s(-1) from needles; 3.0 ± 0.87 cm(2)V(-1)s(-1) from ribbons). This observed mobility is ~8-fold higher than the maximum reported mobility for solution-grown n-channel organic materials (1.5 cm(2)V(-1)s(-1)) and is ~2-fold higher than the highest mobility of any n-channel organic material (~6 cm(2)V(-1)s(-1)). Furthermore, our deposition method is scalable to a 100 mm wafer substrate, with around 50% of the wafer surface covered by aligned crystals. Hence, our method facilitates the fabrication of large amounts of high-quality semiconductor crystals for fundamental studies, and with substantial improvement on the surface coverage of crystals, this method might be suitable for large-area applications based on single crystals of organic semiconductors.

  15. In-Situ Alignment of MnBi Crystals Induced by High Magnetic Field above Curie Temperature

    Institute of Scientific and Technical Information of China (English)

    LIU Yong-Sheng; ZHANG Jin-Cang; REN Zhong-Ming; CAO Shi-Xun

    2007-01-01

    @@ Above Curie temperature, MnBi crystals are aligned in situ along the c-axis in a Bi matrix by a high fabrication magnetic field Hf of 10 T. Magnetic testing shows a pronounced anisotropy in magnetization in directions normal and parallel to the fabrication field, resulting from the alignment. The successful alignment may result from the fact that the easy magnetization direction is along the c-axis of MnBi and the high fabrication field of 10 T is large enough to rotate the MnBi crystal to this direction even though the temperature is above the Curie temperature.

  16. Optical control of plasmonic heating effects using reversible photo-alignment of nematic liquid crystals

    Science.gov (United States)

    Palermo, Giovanna; Cataldi, Ugo; De Sio, Luciano; Bürgi, Thomas; Tabiryan, Nelson; Umeton, Cesare

    2016-11-01

    We demonstrate and characterize an optical control of the plasmonic heat delivered by a monolayer substrate of gold nanoparticles, obtained by modulating the effective refractive index of the neighboring dielectric medium. The effect, which exploits the dependence of the nematic liquid crystal (NLC) refractive index on the molecular director orientation, is realized by using a polarization dependent, light-induced molecular reorientation of a thin film of photo-alignment layer that the NLC is in contact with. For a suitable alignment, plasmonic pumping intensity values ranging from 0.25 W/cm2 to 6.30 W/cm2 can induce up to 17.4 °C temperature variations in time intervals of the order of seconds. The reversibility of the optically induced NLC molecular director orientation enables an active control of the plasmonic photo-induced heat.

  17. Convection in a nematic liquid crystal with homeotropic alignment and heated from below

    Energy Technology Data Exchange (ETDEWEB)

    Ahlers, G. [Univ. of California, Santa Barbara, CA (United States)

    1995-12-31

    Experimental results for convection in a thin horizontal layer of a homeotropically aligned nematic liquid crystal heated from below and in a vertical magnetic field are presented. A subcritical Hopf bifurcation leads to the convecting state. There is quantitative agreement between the measured and the predicted bifurcation line as a function of magnetic field. The nonlinear state near the bifurcation is one of spatio-temporal chaos which seems to be the result of a zig-zag instability of the straight-roll state.

  18. Linear to Circular Polarisation Conversion using Birefringent Properties of Aligned Crystals for Multi-GeV Photons

    CERN Document Server

    Apyan, A; Badelek, B; Ballestrero, S; Biino, C; Birol, I; Cenci, P; Connell, S H; Eichblatt, S; Fonseca, T; Freund, A; Gorini, B; Groess, R; Ispirian, K; Ketel, T; Kononets, Yu V; López, A; Mangiarotti, A; Sellschop, J P Friedel; Shieh, M; Sona, P; Strakhovenko, V M; Uggerhøj, Erik; Uggerhøj, U; Van Rens, B; Velasco, M; Vilakazi, Z Z; Wessely, O; Ünel, G; Kononets, Yu.V.

    2003-01-01

    We present the first experimental results on the use of a thick aligned Si crystal acting as a quarter wave plate to induce a degree of circular polarisation in a high energy linearly polarised photon beam. The linearly polarised photon beam is produced from coherent bremsstrahlung radiation by 178 GeV unpolarised electrons incident on an aligned Si crystal, acting as a radiator. The linear polarisation of the photon beam is characterised by measuring the asymmetry in electron-positron pair production in a Ge crystal, for different crystal orientations. The Ge crystal therefore acts as an analyser. The birefringence phenomenon, which converts the linear polarisation to circular polarisation, is observed by letting the linearly polarised photons beam pass through a thick Si quarter wave plate crystal, and then measuring the asymmetry in electron-positron pair production again for a selection of relative angles between the crystallographic planes of the radiator, analyser and quarter wave plate. The systematics...

  19. Single-walled Carbon Nanotubes Regularly Aligned in Channels of Zeolite Single Crystal

    Institute of Scientific and Technical Information of China (English)

    Zi Kang Tang; Handong Sun; Jiannong Wang

    2000-01-01

    @@ We report the synthesis of single-wall carbon nanotubes (SWCNs) formed in 1-nm-sized channels of zeolite crystal by pyrolysis of tripropylamine molecules. The SWCNs are mono-sized and parallelly aligned along the crystal direction. In the present paper, we report the polarized Raman spectra measured for the wellaligned SWCNs, which gives us information about structural symmetry. Electrical transport properties of the SWNTs are measured in the temperature range of 0.3 K ~ 300 K. The conductivity of the SWCNs is monotonically decreased with decreasing temperature. The observed temperature dependence of zero-field conductance, In(σ) ~ 1/√T, could be explained well in terms of electron localization caused by imperfections and impurities in the nanotubes.

  20. 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.

  1. 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.

    2008-07-01

    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.

  2. 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.

  3. 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.

  4. Reduced operating voltage and grey-to-grey response time in a vertically aligned liquid crystal display using a mixture of two polyimide alignment materials

    Science.gov (United States)

    Lee, Ji-Hoon; Choi, Young Eun; Lee, Jun Hee; Lee, Byeong Hoon; Song, Won Il; Jeong, Kwang-Un; Lee, Gi-Dong; Lee, Seung Hee

    2013-12-01

    We proposed a method to reduce the operating voltage and the grey-to-grey switching time of a vertically aligned liquid crystal display using a mixture of planar and vertical polyimide alignment materials. The surface anchoring energy of the two-polyimide mixture was smaller than that of the pure vertical polyimide and consequently, liquid crystal molecules were easily switched to a planar state with an electric field, resulting in a greater maximum retardation than that of the pure polyimide at the same applied voltage. Rising time was also significantly reduced due to the suppressed optical bouncing effect in the mixed planar polyimide, and the decaying time showed negligible change. With the proposed approach, we can reduce the cell gap to obtain half-wave retardation allowing for faster response time while keeping a low operating voltage.

  5. Light Diffraction of Aligned Polymer Fibers Periodically Dispersed by Phase Separation of Liquid Crystal and Polymer

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2004-12-01

    We have confirmed light diffraction of aligned polymer fibers obtained by a phase separation of an anisotropic-phase solution of liquid crystal and polymer. He—Ne laser light passing through the polymer fibers was scattered in the axis vertical to the fibers, and had two peaks of light intensity symmetrical to the center of the transmitting laser spot. The two peaks were found to be caused by light diffraction due to the periodic polymer-fiber dispersion because the peaks corresponded to values calculated by intervals between the fibers. The periodical fiber networks are considered to be formed by anisotropic spinodal decomposition. This effect can be used to measure the dispersion order of the polymer fibers.

  6. Computational chemistry modeling and design of photoswitchable alignment materials for optically addressable liquid crystal devices

    Science.gov (United States)

    Marshall, K. L.; Sekera, E. R.; Xiao, K.

    2015-09-01

    Photoalignment technology based on optically switchable "command surfaces" has been receiving increasing interest for liquid crystal optics and photonics device applications. Azobenzene compounds in the form of low-molar-mass, watersoluble salts deposited either directly on the substrate surface or after dispersion in a polymer binder have been almost exclusively employed for these applications, and ongoing research in the area follows a largely empirical materials design and development approach. Recent computational chemistry advances now afford unprecedented opportunities to develop predictive capabilities that will lead to new photoswitchable alignment layer materials with low switching energies, enhanced bistability, write/erase fatigue resistance, and high laser-damage thresholds. In the work described here, computational methods based on the density functional theory and time-dependent density functional theory were employed to study the impact of molecular structure on optical switching properties in photoswitchable methacrylate and acrylamide polymers functionalized with azobenzene and spiropyran pendants.

  7. Liquid-crystal anchoring transitions on aligning substrates processed by a plasma beam.

    Science.gov (United States)

    Yaroshchuk, Oleg V; Kiselev, Alexei D; Kravchuk, Ruslan M

    2008-03-01

    We have studied a sequence of anchoring transitions observed in nematic liquid crystals (NLCs) sandwiched between hydrophobic polyimide substrates treated with a plasma beam. There is a pronounced continuous transition from a homeotropic to a slightly tilted (nearly planar) alignment with the easy axis parallel to the incidence plane of the plasma beam (the zenithal transition) which takes place as the exposure dose increases. In NLCs with positive dielectric anisotropy, a further increase in the exposure dose results in in-plane reorientation of the easy axis by 90 degrees (the azimuthal transition). This transition occurs through the twofold degenerate alignment characteristic of second-order anchoring transitions. In contrast to the critical behavior of anchoring, the contact angle of the NLC and water on the treated substrates declines monotonically with increasing exposure dose. It follows that the surface concentration of hydrophobic chains decreases continuously. The anchoring transitions under consideration are qualitatively interpreted by using a simple phenomenological model of competing easy axes which is studied by analyzing anchoring diagrams of generalized polar and nonpolar anchoring models.

  8. Fast gray-to-gray switching of a hybrid-aligned liquid crystal cell

    Science.gov (United States)

    Choi, Tae-Hoon; Kim, Jung-Wook; Yoon, Tae-Hoon

    2015-03-01

    We demonstrate fast gray-to-gray (GTG) switching of a hybrid-aligned liquid crystal cell by applying both vertical and inplane electric fields to liquid crystals (LCs) using a four-terminal electrode structure. The LCs are switched to the bright state through downward tilting and twist deformation initiated by applying an in-plane electric field, whereas they are switched back to the initial dark state through optically hidden relaxation initiated by applying a vertical electric field for a short duration. The top electrode in the proposed device is grounded, which requires a much higher voltage to be applied for in-plane rotation of LCs. Thus, ultrafast turn-on switching of the device is achieved, whereas the turn-off switching of the proposed device is independent of the elastic constants and the viscosity of the LCs so that fast turn-off switching can be achieved. We experimentally obtained a total response time of 0.75 ms. Furthermore, fast GTG response within 3 ms could be achieved.

  9. Progress in liquid crystal (LC) science and technology in honor of Kobayashi's 80th birthday

    CERN Document Server

    Kwok, Hoi-Sing; Ong, Hiap L

    2013-01-01

    The presence of liquid crystal displays (LCDs) marks the advances in mobile phones and television development over the last few decades. Japanese companies were the first to commercialize passive-matrix TNLCDs and, later on, high-resolution activematrix LCDs.Prof. Shunsuke Kobayashi has made essential contributions to Japan's prominence in LCD development throughout this period. He is well-known not only for his own groundbreaking research, but also for the training of many prominent figures in the display industry, both in Japan and in other countries.This book brings together many prominent

  10. Fabrication of a Mono-Domain Alignment Ferroelectric Liquid Crystal Device Using a Polar Self-Assembled Monolayer

    Institute of Scientific and Technical Information of China (English)

    ZOU Zhong-Fei; YAO Li-Shuang; TANG Xian-Zhu; JI Xin-Jian; XUAN Li

    2008-01-01

    A mono-domain ferroelectric liquid crystal device (FLCD) is fabricated using a novel method. The cell used in this method is an asymmetric cell, typically the combination of a polar self-assembled monolayer (SAM) for one substrate and a rubbed polyimide for the other substrate. A defect-free alignment of ferroelectric liquid crystal is fabricated without applying a dc voltage to remove degeneracy in the layer structure. The contact angles of self-assembled monolayer and PI-2942 are measured and the polarity of SAM is higher than the PI alignment. It is found that the polarity of self-assembled monolayer is a key factor in the formation of mono-domain alignment of FLC.

  11. 表面垂直取向对HPDLC光栅特性的影响%Surface vertical alignment effect on performance of holographic polymer dispersed liquid crystal gratings

    Institute of Scientific and Technical Information of China (English)

    李文萃; 舒新建; 杨燚; 黄文彬

    2014-01-01

    为了提高聚合物/液晶(HPDLC)光栅的衍射效率并改善光栅的表面形貌,研究了表面垂直取向处理对HPDLC光栅的影响。首先,研究了表面垂直处理对液晶分子的取向作用,发现垂直取向层对液晶的锚定作用随着盒厚的增加而逐渐减弱,取向层的作用范围大概在3μm ~5μm之间;其次,对相分离程度进行了实验表征,结果表明,随着液晶盒厚度的增加,相分离开始的时间越来越快,并且分离程度也越来越彻底。最后,讨论了表面垂直取向对 HPDLC光栅衍射效率的影响,随着盒厚的增加,相分离出来的液晶微滴形成连续的区域,光栅的衍射效率逐渐升高,当盒厚增加到一定程度,其衍射效率和无取向处理的光栅接近。当盒厚过大时,垂直取向处理对HPDLC光栅散射损失并没有太大的改善,只有当盒厚适中(12μm)时,光栅的衍射效率最高,散射损失最小。%In order to get the holographic polymer dispersed liquid crystal (HPDLC ) grating with high diffraction efficiency and perfect morphology ,the effect of surface vertical alignment on the properties of HPDLC grating was investigated .Firstly ,the effect of the vertical surface treatment on the orientation of liquid crystal molecules was studied .It is found that the vertical anchor effect of liquid crystal decreases with the increase of cell gap and the orientation depth is about 3 μm ~ 5 μm .Secondary ,the characterization experiment of separation was done .And results show that as the cell gap increases ,the surface effect on the bulk LC droplets reduces due to the longer distance .For the thinner cell ,almost all the LC droplets are confined on the inner surfaces of the substrates which cannot flow and coalesce with the neighboring droplets , so the phase separate is not good .However ,if the cell is too thick ,the effect of vertical align‐ment on the LC droplets in the middle of the

  12. Measurement of Coherent Emission and Linear Polarization of Photons by Electrons in the Strong Fields of Aligned Crystals

    CERN Document Server

    Apyan, A; Badelek, B; Ballestrero, S; Biino, C; Birol, I; Cenci, P; Connell, S H; Eichblatt, S; Fonseca, T; Freund, A; Gorini, B; Groess, R; Ispirian, K; Ketel, T; Kononets, Yu V; López, A; Mangiarotti, A; Van Rens, B; Sellschop, J P Friedel; Shieh, M; Sona, P; Strakhovenko, V M; Uggerhøj, Erik; Uggerhøj, U; Ünel, G; Velasco, M; Vilakazi, Z Z; Wessely, O; Kononets, Yu.V.

    2004-01-01

    We present new results regarding the features of high energy photon emission by an electron beam of 178 GeV penetrating a 1.5 cm thick single Si crystal aligned at the Strings-Of-Strings (SOS) orientation. This concerns a special case of coherent bremsstrahlung where the electron interacts with the strong fields of successive atomic strings in a plane and for which the largest enhancement of the highest energy photons is expected. The polarization of the resulting photon beam was measured by the asymmetry of electron-positron pair production in an aligned diamond crystal analyzer. By the selection of a single pair the energy and the polarization of individual photons could be measured in an the environment of multiple photons produced in the radiator crystal. Photons in the high energy region show less than 20% linear polarization at the 90% confidence level.

  13. Rayleigh-Bénard convection in a homeotropically aligned nematic liquid crystal

    CERN Document Server

    Thomas, L; Ahlers, G; Thomas, Leif; Pesch, Werner; Ahlers, Guenter

    1998-01-01

    We report experimental results for convection near onset in a thin layer of a homeotropically aligned nematic liquid crystal heated from below as a function of the temperature difference $\\Delta T$ and the applied vertical magnetic field $H$ and compare them with theoretical calculations. The experiments cover the field range $8 \\alt h \\equiv H/ H_{F} \\alt 80$ ($H_F =$ is the Fréedericksz field). For $h$ less than a codimension-two field $h_{ct} \\simeq 46$ the bifurcation is subcritical and oscillatory, with travelling- and standing-wave transients. Beyond $h_{ct}$ the bifurcation is stationary and subcritical until a tricritical field $h_t= 57.2$ is reached, beyond which it is supercritical. The bifurcation sequence as a function of $h$ found in the experiment confirms the qualitative aspects of the theoretical predictions. However, the value of $h_{ct}$ is about 10% higher than the predicted value and the results for $k_c$ are systematically below the theory by about 2% at small $h$ and by as much as 7% ne...

  14. Hybrid graphene nematic liquid crystal light scattering device

    Science.gov (United States)

    Qasim, M. M.; Khan, A. A.; Kostanyan, A.; Kidambi, P. R.; Cabrero-Vilatela, A.; Braeuninger-Weimer, P.; Gardiner, D. J.; Hofmann, S.; Wilkinson, T. D.

    2015-08-01

    A hybrid graphene nematic liquid crystal (LC) light scattering device is presented. This device exploits the inherent poly-crystallinity of chemical vapour deposited (CVD) graphene films to induce directional anchoring and formation of LC multi-domains. This thereby enables efficient light scattering without the need for crossed polarisers or separate alignment layers/additives. The hybrid LC device exhibits switching thresholds at very low electric fields (crossed polarisers or separate alignment layers/additives. The hybrid LC device exhibits switching thresholds at very low electric fields (< 1 V μm-1) and repeatable, hysteresis free characteristics. This exploitation of LC alignment effects on CVD graphene films enables a new generation of highly efficient nematic LC scattering displays as well as many other possible applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04094a

  15. Dynamic states of swimming bacteria in a nematic liquid crystal cell with homeotropic alignment

    Science.gov (United States)

    Zhou, Shuang; Tovkach, Oleh; Golovaty, Dmitry; Sokolov, Andrey; Aranson, Igor S.; Lavrentovich, Oleg D.

    2017-05-01

    Flagellated bacteria such as Escherichia coli and Bacillus subtilis exhibit effective mechanisms for swimming in fluids and exploring the surrounding environment. In isotropic fluids such as water, the bacteria change swimming direction through the run-and-tumble process. Lyotropic chromonic liquid crystals (LCLCs) have been introduced recently as an anisotropic environment in which the direction of preferred orientation, the director, guides the bacterial trajectories. In this work, we describe the behavior of bacteria B. subtilis in a homeotropic LCLC geometry, in which the director is perpendicular to the bounding plates of a shallow cell. We demonstrate that the bacteria are capable of overcoming the stabilizing elastic forces of the LCLC and swim perpendicularly to the imposed director (and parallel to the bounding plates). The effect is explained by a finite surface anchoring of the director at the bacterial body; the role of surface anchoring is analyzed by numerical simulations of a rod realigning in an otherwise uniform director field. Shear flows produced by a swimming bacterium cause director distortions around its body, as evidenced both by experiments and numerical simulations. These distortions contribute to a repulsive force that keeps the swimming bacterium at a distance of a few micrometers away from the bounding plates. The homeotropic alignment of the director imposes two different scenarios of bacterial tumbling: one with an 180° reversal of the horizontal velocity and the other with the realignment of the bacterium by two consecutive 90° turns. In the second case, the angle between the bacterial body and the imposed director changes from 90° to 0° and then back to 90° the new direction of swimming does not correlate with the previous swimming direction.

  16. Defect structures in liquid crystals bounded by microwrinkles

    Science.gov (United States)

    Ohzono, Takuya

    2013-09-01

    Spatially confined liquid crystals (LCs) exhibit non-uniform alignment, often accompanied by self-organized topological defects of non-trivial shape in response to imposed boundary conditions and geometry. Here we show that a nematic LC, when confined in a sinusoidal microwrinkle groove, exhibits a new periodic arrangement of twist deformations and a zigzag line defect. This periodic ordering results from the inherent LC elastic anisotropy and the antagonistic boundary conditions at the top flat LC and the curved LC-groove interfaces. The effect of the LC thickness on the stability of the line defect is also shown.

  17. Plasmonic Photopatterning of Complex Molecular Orientations in Liquid Crystals

    Science.gov (United States)

    Guo, Yubing; Jiang, Miao; Peng, Chenhui; Sun, Kai; Yaroshchuk, Oleg; Lavrentovich, Oleg; Wei, Qi-Huo

    Aligning liquid crystal (LC) molecules in spatially non-uniform patterns are highly demanded for applications such as programmable origami and liquid crystal enabled nonlinear electrokinetics. We developed a high resolution projection photoalignment technique for patterning arbitrary LC alignment fields. The photoalignment is based on carefully engineered metasurfaces, or dubbed as plasmonic metamasks (PMMs). When illuminated by light, the PMMs generate patterns of both light intensity and polarization. By projecting the light transmitted through the PMMs onto liquid crystal cells coated with photosensitive materials, alignment patterns predesigned in polarization patterns of the PMMs can be imposed in liquid crystals. This technique makes the liquid crystal alignment a repeatable and scalable process similar to conventional photolithography, promising various applications. National Science Foundation CMMI-1436565.

  18. Homeotropic Alignment of a Discotic Liquid Crystal Induced by a Sacrificial Layer

    DEFF Research Database (Denmark)

    Pouzet, Eric; De Cupere, Vinciane; Heintz, Christophe

    2009-01-01

    A convenient method to induce face-on orientation of an alkoxy phtalocyanine discotic mesogen is described. The alignment is imposed by the confinement of the discotic thin films with a top sacrificial polymer layer that is easily removed by washing with a selective solvent, after thermal annealing...... to the substrate in an essentially homeotropic arrangement over large lateral length scales and the persistence of this desirable alignment after removal of the layer....

  19. Measurement of anchoring coefficient of homeotropically aligned nematic liquid crystal using a polarizing optical microscope in reflective mode

    Directory of Open Access Journals (Sweden)

    Sang-In Baek

    2015-09-01

    Full Text Available Although the homeotropic alignment of liquid crystals is widely used in LCD TVs, no easy method exists to measure its anchoring coefficient. In this study, we propose an easy and convenient measurement technique in which a polarizing optical microscope is used in the reflective mode with an objective lens having a low depth of focus. All measurements focus on the reflection of light near the interface between the liquid crystal and alignment layer. The change in the reflected light is measured by applying an electric field. We model the response of the director of the liquid crystal to the electric field and, thus, the change in reflectance. By adjusting the extrapolation length in the calculation, we match the experimental and calculated results and obtain the anchoring coefficient. In our experiment, the extrapolation lengths were 0.31 ± 0.04 μm, 0.32 ± 0.08 μm, and 0.23 ± 0.05 μm for lecithin, AL-64168, and SE-5662, respectively.

  20. Mineral crystal alignment in mineralized fracture callus determined by 3D small-angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Liu Yifei; Manjubala, Inderchand; Fratzl, Peter [Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam (Germany); Roschger, Paul [4th Medical Department, Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1140 Vienna (Austria); Schell, Hanna; Duda, Georg N, E-mail: fratzl@mpikg.mpg.d [Julius Wolff Institut and Center for Musculoskeletal Surgery, Charite- University Medicine Berlin, Augustenburger Platz 1, 13353 Berlin (Germany)

    2010-10-01

    Callus tissue formed during bone fracture healing is a mixture of different tissue types as revealed by histological analysis. But the structural characteristics of mineral crystals within the healing callus are not well known. Since two-dimensional (2D) scanning small-angle X-ray scattering (sSAXS) patterns showed that the size and orientation of callus crystals vary both spatially and temporally [1] and 2D electron microscopic analysis implies an anisotropic property of the callus morphology, the mineral crystals within the callus are also expected to vary in size and orientation in 3D. Three-dimensional small-angle X-ray scattering (3D SAXS), which combines 2D SAXS patterns collected at different angles of sample tilting, has been previously applied to investigate bone minerals in horse radius [2] and oim/oim mouse femur/tibia [3]. We implement a similar 3D SAXS method but with a different way of data analysis to gather information on the mineral alignment in fracture callus. With the proposed accurate yet fast assessment of 3D SAXS information, it was shown that the plate shaped mineral particles in the healing callus were aligned in groups with their predominant orientations occurring as a fiber texture.

  1. Tracking alignment from the moment of inertia tensor (TRAMITE) of biomolecules in neutral dilute liquid crystal solutions.

    Science.gov (United States)

    Azurmendi, Hugo F; Bush, C Allen

    2002-03-20

    NMR residual dipolar couplings between couple of nuclei PQ, (1)D(PQ), measured on neutral dilute liquid crystal solutions, provide valuable long-range structural information of biomolecules. An accurate and simple method for the prediction of the alignment produced as consequence of sterical interactions between the solute and the bicelles is proposed called TRacking Alignment from Moment of Inertia TEnsor--TRAMITE. The method use the information encoded in the moment of inertia of the molecules to calculate the orientation tensor and predict the (1)D(PQ) values. Examples on proteins and oligosaccharides are presented which cover a wide range of sizes and shapes, along with a scheme for the application of the method to the analysis of flexible molecules.

  2. Observation of applied voltage response of dye-doped liquid crystal by optical measurement of real and imaginary parts of complex refractive index

    Science.gov (United States)

    Sakamoto, Moritsugu; Bannai, Kenta; Noda, Kohei; Sasaki, Tomoyuki; Ono, Hiroshi

    2017-09-01

    The behavior of liquid crystal (LC) molecules and dye molecules in a dye-doped liquid crystal (DDLC) under a voltage application condition was quantitatively investigated. To observe the reorientation of these molecules, the real and imaginary parts of the complex refractive index were simultaneously and individually measured using an optical interferometer. The obtained results indicate that the alignment of dye molecules doped in DDLC occurs following the electrically responding LC molecules, near the Freedericksz transition region of LC.

  3. Attempt to detect diamagnetic anisotropy of dust-sized crystal orientated to investigate the origin of interstellar dust alignment

    Science.gov (United States)

    Takeuchi, T.; Hisayoshi, K.; Uyeda, C.

    2013-03-01

    Diamagnetic anisotropy Δ χ dia was detected on a submillimeter-sized calcite crystal by observing the rotational oscillation of its magnetically stable axis with respect to the magnetic field direction. The crystal was released in an area of microgravity generated by a 1.5-m-long drop shaft. When the oscillations are observable, the present method can measure Δ χ dia of crystal grains irrespective of how small they are without measuring the sample mass. In conventional Δ χ measurements, the background signal from the sample holder and the difficulty in measuring the sample mass prevent measurement of Δ χ dia for small samples. The present technique of observing Δ χ dia of a submillimeter-sized single crystal is a step toward realizing Δ χ dia measurements of micron-sized grains. The Δ χ dia values of single micron-sized grains can be used to assess the validity of a dust alignment model based on magnetic torque that originates from the Δ χ dia of individual dust particles.

  4. Homeotropic Alignment of a Discotic Liquid Crystal Induced by a Sacrificial Layer

    DEFF Research Database (Denmark)

    Pouzet, Eric; De Cupere, Vinciane; Heintz, Christophe;

    2009-01-01

    . Thin films have been characterized by optical and atomic force microscopy, UV-Vis absorption spectroscopy, and grazing incidence wide angle X-ray scattering. The data converge in showing the central role of the sacrificial layer in promoting alignment with the planar molecules orienting parallel...

  5. Alignment of smectic mesogens over engineered surfaces

    Science.gov (United States)

    Chandran, Achu; Joshi, Tilak; Khanna, P. K.; Mehta, Dalip. S.; Haranath, D.; Biradar, Ashok M.

    2017-07-01

    The alignment of smectic C* liquid crystals (LCs) has been manipulated over and near different surfaces such as bare glass, indium tin oxide (ITO) coated glass, patterned glass, and near spacers. The LC sample cell is made of one ITO coated glass plate and other having striped ITO with a Mylar spacer maintaining a finite cell gap between them. Laser scribing is used to make striped ITO, while the scribed area results in the formation of the patterned glass surface. The geometry of the cell is such that overlapped ITO lie in the middle and spacers are placed in the two extreme corners of the cell. The alignment of LC is found to be homeotropic over the ITO coated glass, while it is planar near the spacer. Interestingly, a transition from homeotropic to planar is observed while moving away from the middle towards either corner of the cell. The origin of both types of alignment in the same cell has been explained by considering the difference in the surface energy of different surfaces. This work renders new advancement towards the manipulation of LC alignment using different surfaces and interfaces for advanced electro-optical and photonic devices based on LCs.

  6. 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.

  7. Chain alignment for improved properties - Optimization of PLA and PHB-V by crystallization and reinforcement

    Science.gov (United States)

    Moser, K.; Bergmann, B.; Diemert, J.; Elsner, P.

    2014-05-01

    In this paper two promising ways to improve the material characteristics of PLA and PHB-V are presented by showing their positive effects on mechanical, optical, and thermal properties. The optimization is achieved by increasing the crystallization from the melt of the polymer chains and the other by means of a reinforcement of the matrices by bio-based materials. In the case of crystallization specific nucleating agents and optimized process parameters promote optimized crystallization conditions and lead particularly in toughness to significant improvements. In addition to crystallization the introduction of cellulose-based reinforcing materials is also a good alternative to improve the ductility of a biopolymer matrix considerably. Due to their polar surface structure cellulose fibres are favouring a very good interaction to the also polar biopolymers. In addition, the polar surfaces of both materials results in very homogeneous dispersion within the compound.

  8. Vertically aligned and hexagonal crystal ZnSe nanoribbon arrays on Zn substrates

    Institute of Scientific and Technical Information of China (English)

    PANG Qi; ZHAO Li-juan; GE Wei-kun; WANG Jian-nong; FANG Yue-ping; WEN Xiao-gang; YANG Shi-he

    2006-01-01

    The vertically aligned and hexagonal ZnSe nanoribbon array can be easily obtained by heating ZnSe:0.38 en precursors (en=ethylenediamine),while ZnSe precursor nanoribbon arrays are grown directly on Zn foils in en using the solvothermal method.The nanoribbons are mostly about 4 nm in thickness,100-300 nm in width,and 2 μm in length.The characteristics observed using scanning electron microscopy and X-ray diffraction indicate that the ZnSe precursor as well as ZnSe nanoribbons are vertically aligned on almost the whole zinc foil surface and form a large-scale uniform array.Particularly,ZnSe precursor nanoribbons are hybrid materials of ZnSe and en,while ZnSe nanoribbons are in the from of hexagonal structures.Possible growth mechanisms of the ZnSe precursor nanoribbon arrays are also proposed.

  9. Liquid crystal wavefront corrector with modal response based on spreading of the electric field in a dielectric material

    NARCIS (Netherlands)

    Loktev, M.; Vdovine, G.V.; Klimov, N.; Kotova, S.

    2007-01-01

    A novel liquid crystal (LC) wavefront corrector with smooth modal influence functions is proposed and realized. The device consists of a thin layer of planar aligned nematic LC sandwiched between a glass plate with a conductive electrode and a plate made of ceramic material with a very high dielectr

  10. Liquid crystal wavefront corrector with modal response based on spreading of the electric field in a dielectric material

    NARCIS (Netherlands)

    Loktev, M.; Vdovine, G.V.; Klimov, N.; Kotova, S.

    2007-01-01

    A novel liquid crystal (LC) wavefront corrector with smooth modal influence functions is proposed and realized. The device consists of a thin layer of planar aligned nematic LC sandwiched between a glass plate with a conductive electrode and a plate made of ceramic material with a very high

  11. Solution-grown small-molecule organic semiconductor with enhanced crystal alignment and areal coverage for organic thin film transistors

    Directory of Open Access Journals (Sweden)

    Sheng Bi

    2015-07-01

    Full Text Available Drop casting of small-molecule organic semiconductors typically forms crystals with random orientation and poor areal coverage, which leads to significant performance variations of organic thin-film transistors (OTFTs. In this study, we utilize the controlled evaporative self-assembly (CESA method combined with binary solvent system to control the crystal growth. A small-molecule organic semiconductor,2,5-Di-(2-ethylhexyl-3,6-bis(5″-n-hexyl-2,2′,5′,2″]terthiophen-5-yl-pyrrolo[3,4-c]pyrrole-1,4-dione (SMDPPEH, is used as an example to demonstrate the effectiveness of our approach. By optimizing the double solvent ratios, well-aligned SMDPPEH crystals with significantly improved areal coverage were achieved. As a result, the SMDPPEH based OTFTs exhibit a mobility of 1.6 × 10−2 cm2/V s, which is the highest mobility from SMDPPEH ever reported.

  12. Optical study of the molecular alignment in a nematic liquid crystal in an oblique magnetic field

    OpenAIRE

    Oldano, C.; Miraldi, E.; Strigazzi, A.; Taverna Valabrega, P.; Trossi, L.

    1984-01-01

    The light intensity I transmitted through a homeotropically oriented nematic liquid crystal slab held between crossed polarizers, as a function of the angle θH of an applied magnetic field, is calculated for oblique light incidence. The presence of singular points in the I vs. θ H curve which are related to the elastic constants of the liquid crystal is demonstrated One of these points, found here for the first time, for small angles of incidence depends only on the ratio K33/Χ a, and allows ...

  13. 一种改善胆固醇液晶排列的简易方法%One Method for Improving the Alignment of Cholesteric Liquid Crystal

    Institute of Scientific and Technical Information of China (English)

    罗吉祥; 黄玉华; 晋敏

    2014-01-01

    Because a lot of defects will be formed in thick cholesteric liquid crystals (CLC),which destroys its photonic bandgap structure and dramatically reduces the transmissivity,its applications in photonics have been dramatically limited.In order to overcome this problem,we developed a method to improve the alignment of the liquid crystal (LC) molecules in the CLC sample.The procedure is as follows:firstly,high enough AC voltage with 1 kHz is applied to swithch on the CLC sample.After switching on and off the sample at this voltage for several times,massage is done on the CLC surface for a while.The results show that after massage,the defects inside the CLC sample can be dramatically reduced,therefore the planar structure of CLC is greatly improved,and the transmission is drastically increased.It indicates that this method can be used for fabricating thicker CLC samples.Above all,it provides a useful fabrication basis for the CLC's applications in photonics.%胆固醇液晶在厚的液晶盒中会形成大量缺陷,以至于其光子晶体结构被破坏,透射率急剧降低,严重影响了晶体光学性质及其应用.针对此提出了一种能有效改善胆固醇液晶分子排列的简易方法,其过程为先通过给胆固醇液晶施加足以驱动胆固醇液晶分子的交流电压,并在该交流电压下开关数次后对其进行摩擦处理.结果表明经过摩擦处理后,胆固醇液晶样品的内部缺陷明显减少了,其平面结构相应得到了较大的改善,样品的透射率显著提高,由摩擦前的模糊变成摩擦后的透明.表明该方法可以用于制备高质量的厚胆固醇液晶样品,从而为胆固醇液晶在光学领域的应用提供了必要条件.

  14. The development of self-assembled liquid crystal display alignment layers

    NARCIS (Netherlands)

    Hoogboom, J.; Elemans, J.A.A.W.; Rowan, A.E.; Rasing, T.H.M.; Nolte, R.J.M.

    2007-01-01

    From simple pocket calculators to mobile telephones and liquid crystal display (LCD)-TV, over the past few decades, devices based on LCD technology have proliferated and can now be found in all conceivable aspects of everyday life. Although used in cutting-edge technology, it is surprising that a vi

  15. Alignment of TiO2 (Anatase Crystal of Dye-Sensitized Solar Cells by External Magnetic Field

    Directory of Open Access Journals (Sweden)

    Na-Yeong Hong

    2013-01-01

    Full Text Available In this study, magnetic field (B was applied on TiO2 (anatase of dye-sensitized solar cell (DSC for alignment of crystal. Magnetic field was applied on TiO2 when deposited TiO2 on the fluorine tin oxide (FTO was dried at 373 K for crystalline orientation. And applying time of B was varied 0~25 min. Characteristics of the magnetic field applied TiO2 films were analyzed by X-ray diffraction (XRD, high resolution transmission electron microscopy (HRTEM, scanning electron microscopy (SEM, and electrochemical impedance spectroscopy (EIS. Current-voltage characteristics were also analyzed using solar simulator, and it was confirmed that the energy conversion efficiency of 41% was increased. Finally, it was identified that the magnetic field affected orientation of TiO2, resulting in the enhancement of the performance of the DSC.

  16. Characterization of a parallel aligned liquid crystal on silicon and its application on a Shack-Hartmann sensor

    Science.gov (United States)

    Lobato, L.; Márquez, A.; Lizana, A.; Moreno, I.; Iemmi, C.; Campos, J.

    2010-08-01

    In this paper, the characterization and the optimization of a parallel aligned (PA) liquid crystal on silicon display (LCoS) has been conducted with the aim to apply it to the generation of a microlenses array in a Shack-Hartmann (SH) sensor. The entire sensor setup has been experimentally implemented from scratch. Results obtained for several aberrated wavefront measurements show the suitability of these devices in this particular application. Due to the well-known dynamic properties of LCoS, these devices allow for an easy choice of the parameters of the SH sensor, i.e. the selection of the suitable focal length and aperture of the microlenses of the array, which will definitely determine the dynamic range and the lateral resolution of the SH sensor.

  17. Dendronized Polyimides Bearing Long-Chain Alkyl Groups and Their Application for Vertically Aligned Nematic Liquid Crystal Displays

    Directory of Open Access Journals (Sweden)

    Yusuke Tsuda

    2009-11-01

    Full Text Available Polyimides having dendritic side chains were investigated. The terphenylene diamine monomer having a first-generation monodendron, 3,4,5-tris(n-dodecyloxy-benzoate and the monomer having a second-generation monodendron, 3,4,5-tris[-3’,4’,5’-tri(n-dodecyloxybenzyloxy]benzoate were successfully synthesized and the corresponding soluble dendritic polyimides were obtained by polycondensation with conventional tetracarboxylic dianhydride monomers such as benzophenone tertracarboxylic dianhydride (BTDA. The two-step polymerizations in NMP that is a general method for the synthesis of soluble polyimides is difficult; however, the expected dendritic polyimides can be obtained in aromatic polar solvents such as m-cresol and pyridine. The solubility of these dendoronized polyimides is characteristic; soluble in common organic solvents such as dichloromethane, chloroform, toluene and THF. These dendronized polyimides exhibited high glass transition temperatures and good thermal stability in both air and under nitrogen. Their application as alignment layers for LCDs was investigated, and it was found that these polyimides having dendritic side chains were applicable for the vertically aligned nematic liquid crystal displays (VAN-LCDs.

  18. Enhancement of electromagnetic showers initiated by ultrarelativistic electrons in aligned thick germanium crystals

    Science.gov (United States)

    Baurichter, A.; Mikkelsen, U.; Kirsebom, K.; Medenwaldt, R.; Møller, S.; Uggerhøj, E.; Worm, T.; Elsener, K.; Ballestrero, S.; Sona, P.; Romano, J.; Biino, C.; Moore, R.; Vilakazi, Z. Z.

    1996-10-01

    The distribution of the energy deposited in thin silicon detectors placed on the downstream side of a thick germanium single crystal bombarded with a 70, 150 and 250 GeV electron beam along directions close to the axis or {110} and {100} planes has been measured. The enhancement of the shower with respect to random incidence, as reflected in the higher value of the centroid of the distribution, is studied as a function of the incidence angle to the axis or plane.

  19. Liquid crystal wavefront corrector with modal response based on spreading of the electric field in a dielectric material

    OpenAIRE

    Loktev, M.; Vdovine, G.V.; Klimov, N.; Kotova, S.

    2007-01-01

    A novel liquid crystal (LC) wavefront corrector with smooth modal influence functions is proposed and realized. The device consists of a thin layer of planar aligned nematic LC sandwiched between a glass plate with a conductive electrode and a plate made of ceramic material with a very high dielectric constant. Control electrodes are positioned on the back side of the ceramic plate, opposite to the LC. The modal character of the response is determined by spreading of the electric field in the...

  20. Modulation of unpolarized light in planar aligned subwavelength-pitch deformed-helix ferroelectric liquid crystals

    CERN Document Server

    Kesaev, Vladimir V; Kiselev, Alexei D

    2016-01-01

    We study the electro-optic properties of subwavelength-pitch deformed-helix ferroelectric liquid crystals (DHFLC) illuminated with unpolarized light. In the experimental setup based on the Mach-Zehnder interferometer, it was observed that the reference and the sample beams being both unpolarized produce the interference pattern which is insensitive to rotation of in-plane optical axes of the DHFLC cell. We find that the field-induced shift of the interference fringes can be described in terms of the electrically dependent Pancharatnam relative phase determined by the averaged phase shift, whereas the visibility of the fringes is solely dictated by the phase retardation.

  1. Enhanced shower formation in aligned thick germanium crystals and discrimination against charged hadrons

    Science.gov (United States)

    Baurichter, A.; Kirsebom, K.; Medewaldt, R.; Mikkelsen, U.; Møller, S.; Uggerhøj, E.; Worm, T.; Elsener, K.; Ballestrero, S.; Sona, P.; Romano, J.

    1995-11-01

    The distribution of the energy released in a thin silicon detector placed on the downstream side of a thick germanium single crystal bombarded with a 150 GeV electron or pion beam along directions close to the axis or along random directions has been investigated. In view of a possible application to very high energy gamma ray astronomy and particle physics, the intrinsic capability of such a device to reject, on the basis of energy discrimination, unwanted events due to charged hadrons together with the resulting loss of efficiency for the detection of showers initiated by high energy electrons, is determined as a function of the chosen energy threshold.

  2. Super-fast switching of twisted nematic liquid crystals with a single-wall-carbon-nanotube-doped alignment layer

    Science.gov (United States)

    Liu, Yang; Lim, Young Jin; Kundu, Sudarshan; Lee, Seung Hee; Lee, Gi-Dong

    2015-03-01

    The application of a single-wall carbon-nanotube (SWCNT) and polyimide (PI) composite thin film on an indium tin-oxide (ITO) glass substrate, working as the command surface in a twisted nematic liquid crystal display (LCD), is described. SWCNTs were chopped and oxidized in a strong acid medium to make them more miscible in a polyimide solution. A film of this newly-developed PISWCNT composite was rubbed to determine the director direction for the LC molecules. The newlyfabricated command surface was examined using a laser beam profiler and atomic force microscopy. Sizes of shortened SWCNTs were characterized by using field-emission scanning electron microscopy (FE-SEM). Finally, small-sized test panels were fabricated from this composite-coated ITO glass, and their electro-optic performances were measured. Although the operating voltage to switch a cell was increased by around 41%, the switching speed was improved remarkably. The rise time of the test cells was found to be improved by around 10.12% and the decay time by around 29.77%. Thus, an overall improvement of around 16.12% in the total switching time was achieved. The change in the surface morphology of the newly-developed composite materials was found to be one of the factors responsible for the faster switching of the device. Detailed discussions are given in this report to explain the faster switching of the newly-developed twisted nematic liquid crystal display (TN-LCD). The device can be useful for practical applications.

  3. Rapid charge transport in dye-sensitized solar cells made from vertically aligned single-crystal rutile TiO(2) nanowires.

    Science.gov (United States)

    Feng, Xinjian; Zhu, Kai; Frank, Arthur J; Grimes, Craig A; Mallouk, Thomas E

    2012-03-12

    A rapid solvothermal approach was used to synthesize aligned 1D single-crystal rutile TiO(2) nanowire (NW) arrays on transparent conducting substrates as electrodes for dye-sensitized solar cells. The NW arrays showed a more than 200 times faster charge transport and a factor four lower defect state density than conventional rutile nanoparticle films.

  4. Parallel aligned liquid crystal on silicon display based optical set-up for the generation of polarization spatial distributions

    Science.gov (United States)

    Estévez, Irene; Lizana, Angel; Zheng, Xuejie; Peinado, Alba; Ramírez, Claudio; Martínez, Jose Luis; Márquez, Andrés.; Moreno, Ignacio; Campos, Juan

    2015-06-01

    Liquid Crystals on Silicon (LCOS) displays are a type of LCDs that work in reflection. Such devices, due to the double pass that the light beam performs through the LC cells, lead to larger phase modulation than transmissive LCDs with the same thickness. By taking advantage of this modulation capability exhibited by LCOS displays, we propose a new experimental set-up which is able to provide customized state of polarization spatial distributions just by means of a single LCOS display. To this aim, a double reflection on different halves of the display is properly performed. This fact is achieved by including a compact optical system that steers the light and performs a proper polarization plane rotation. The set-up has been experimentally implemented and some experimental concerns are discussed. The suitability of the system is provided by generating different experimental spatial distributions of polarization. In this regard, well-known polarization distributions, as axial, azimuthal or spiral linear polarization patterns are here provided. Based on the excellent results obtained, the suitability of the system to generate different spatially variant distributions of polarization is validated.

  5. Polymer Wall Formation Using Liquid-Crystal/Polymer Phase Separation Induced on Patterned Polyimide Films

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2004-12-01

    We could form lattice-shaped polymer walls in a liquid crystal (LC) layer through the thermal phase separation of an LC/polystyrene solution between substrates with polyimide films etched by short-wavelength ultraviolet irradiation using a photomask. The LC wetting difference between the polyimide and substrate surfaces caused the coalescence of growing LC droplets on patterned polyimide films with the progress of phase separation. Consequently, polymer walls were formed on substrate surface areas without polyimide films. The shape of the polymer wall formed became sharp with the use of rubbed polyimide films because the nucleation of growing LC droplets concentrated on the patterned polyimide films. It is thought that the increase in the alignment order of LC molecules in the solution near the rubbed polyimide films promotes the formation of LC molecular aggregation, which becomes the growth nuclei of LC droplets.

  6. Aligned hemozoin crystals in curved clusters in malarial red blood cells revealed by nanoprobe X-ray Fe fluorescence and diffraction

    DEFF Research Database (Denmark)

    Kapishnikov, Sergey; Berthing, Trine; Hviid, Lars

    2012-01-01

    The human malaria parasite Plasmodium falciparum detoxifies the heme byproduct of hemoglobin digestion in infected red blood cells by sequestration into submicron-sized hemozoin crystals. The crystal is composed of heme units interlinked to form cyclic dimers via reciprocal Fe-O (propionate) bonds...... fluorescence and diffraction. The X-ray patterns indicated the presence of hemozoin clusters, each comprising several crystals aligned along their needle c axes and exposing {100} side faces to an approximately cylindrical surface, suggestive of nucleation via a common lipid layer. This experimental finding...

  7. Enhanced shower formation in aligned thick germanium crystals and discrimination against charged hadrons

    Energy Technology Data Exchange (ETDEWEB)

    Baurichter, A. [Aarhus Univ. (Denmark). Inst. for Synchrotron Radiat.; Kirsebom, K. [Aarhus Univ. (Denmark). Inst. for Synchrotron Radiat.; Medewaldt, R. [Aarhus Univ. (Denmark). Inst. for Synchrotron Radiat.; Mikkelsen, U. [Aarhus Univ. (Denmark). Inst. for Synchrotron Radiat.; Moeller, S. [Aarhus Univ. (Denmark). Inst. for Synchrotron Radiat.; Uggerhoej, E. [Aarhus Univ. (Denmark). Inst. for Synchrotron Radiat.; Worm, T. [Aarhus Univ. (Denmark). Inst. for Synchrotron Radiat.; Elsener, K. [European Organization for Nuclear Research, Geneva (Switzerland); Ballestrero, S. [Dipartimento di Fisica, University of Florence and INFN Sezione di Firenze, Largo E. Fermi 2, 50125 Florence (Italy); Sona, P. [Dipartimento di Fisica, University of Florence and INFN Sezione di Firenze, Largo E. Fermi 2, 50125 Florence (Italy); Romano, J. [Dipartimento di Fisica, University La Sapienza-Rome and INFN Sezione di Roma, P.le A. Moro 5, 00185 Rome (Italy)

    1995-11-01

    The distribution of the energy released in a thin silicon detector placed on the downstream side of a thick germanium single crystal bombarded with a 150 GeV electron or pion beam along directions close to the left angle 110 right angle axis or along random directions has been investigated. In view of a possible application to very high energy gamma ray astronomy and particle physics, the intrinsic capability of such a device to reject, on the basis of energy discrimination, unwanted events due to charged hadrons together with the resulting loss of efficiency for the detection of showers initiated by high energy electrons, is determined as a function of the chosen energy threshold. (orig.).

  8. Significantly improving oxygen barrier properties of polylactide via constructing parallel-aligned shish-kebab-like crystals with well-interlocked boundaries.

    Science.gov (United States)

    Bai, Hongwei; Huang, Chunmei; Xiu, Hao; Zhang, Qin; Deng, Hua; Wang, Ke; Chen, Feng; Fu, Qiang

    2014-04-14

    Recently, some attempts have been made to enhance the gas barrier properties of semicrystalline polymers by precisely controlling the arrangement of their impermeable crystalline lamellae. However, it is still a great challenge to achieve regular arrangement of the lamellae along the direction perpendicular to the gas diffusion path, especially using conventional polymer processing technologies. This work presents a novel and simple strategy to dramatically improve oxygen barrier performance of biobased and biodegradable polylactide (PLA) through constructing parallel-aligned shish-kebab-like crystals with well-interlocked boundaries with the aid of a highly active nucleating agent. The nucleating agent was introduced into PLA by melting compounding and the sheet-like specimens were fabricated by compression molding. We demonstrate that the fibrillar nucleating agent dispersed in PLA melt can serve as shish to induce the change of crystallization habit of PLA from isotopic spherulitic crystals to unique shish-kebab-like crystals and the shear flow in the compression molding can induce the highly ordered alignment of the nucleating agent fibrils as well as the subsequent shish-kebab-like crystals along the direction parallel to the sheet surface. More importantly, the growing lamellae are found to interpenetrate and tightly interlock with each other at the boundary regions of the shish-kebab-like crystals in the later stage of the crystallization, forming a densely packed nanobrick wall structure to prevent gas molecules from permeating through the crystals and thus imparting the PLA sheets with unprecedentedly low oxygen permeability. This work provides not only a successful example of preparing semicrystalline polymer with super gas barrier properties by tailoring crystal superstructure but also a promising route to rapidly fabricate high-performance food packaging materials via industrially meaningful melt processing.

  9. Effect of Molecular Weight on Liquid Crystal Photoalignment by Photosensitive Polyester Containing Thrifluoromethyl Moieties

    Institute of Scientific and Technical Information of China (English)

    FEI Chun-Hong; PENG Zeng-Hui; LV Feng-Zhen; ZHANG Ling-Li; YAO Li-Shuang; XUAN Li

    2006-01-01

    @@ We investigate the liquid-crystal (LC) alignment direction on photoalignment films formed from photosensitive polyester containing thrifluoromethyl moieties (PPDA ) with various molecular weights by crossed polarized optical microscopy. It is found that LC alignment behaviour changes with molecular weight of PPDA. The LC alignment on PPDA irradiated films with the highest molecular weight is homogeneous, while those with low and intermediate molecular weights are homeotropic. However, surface morphologies show weak dependence on molecular weight. The surfaces are smooth and there is no clear morphological anisotropy on these aligned films observed by an atomic force microscope. The surface energies of the irradiated films are also measured by using an indirect contact-angle method where both surface energy and its polar componentincrease with increasing molecular weight. Different polar surface energies can be considered as a main reason for different alignment characteristics.

  10. Photo-alignment of low-molecular mass nematic liquid crystals on photochemically bifunctional chalcone-epoxy film by irradiation of a linearly polarized UV light

    CERN Document Server

    Choi, D H

    2002-01-01

    Photocrosslinkable chalcone-epoxy compound comprising 1,3-bis-(4-hydroxy-phenyl)-propenone was synthesized for fabricating the photo-alignment layer of liquid crystals. Chalcone group was introduced into the main chain unit of the epoxy oligomer. We observed a photodimerization behavior and an optical anisotropy of this material by irradiation of a linearly polarized UV(LP-UV) light. With a trace amount of cationic photo initiator (TRS-HFA), polymerization of epoxy groups was also conducted at the similar wavelength range used for photodimerization . Linearly polarized UV irradiation on the chalcone-epoxy films with cationic photoinitiator induced optical anisotropy of the film and the resultant film can be used for alignment layers for low molecular weight nematic liquid crystals.

  11. DNA hosted and aligned in aqueous interstitia of a lamellar liquid crystal – a membrane–biomacromolecule interaction model system

    KAUST Repository

    Carlsson, Nils

    2013-01-01

    We report that DNA molecules can be intercalated and macroscopically oriented in the aqueous interstitia of a lyotropic lamellar liquid crystal. Using UV-vis linear dichroism and fluorescence spectroscopy we show that double-stranded oligonucleotides (25 base pairs) in the water-octanoate-decanol system remain base-paired in the B conformation and are confined in two dimensions, with the helix axis preferentially parallel to the lipid bilayer surfaces but free to rotate within this plane. The degree of helix confinement and the corresponding 2-D orientation can be improved by decreasing the thickness of the water interstitia via the fraction of water in the ternary mixture. Not surprisingly, the corresponding single-stranded oligonucleotides are not aligned, with their persistence length being short in comparison to the lamellar interstitium thickness. We propose this as a model system for studying interactions of DNA-ligand complexes near a lipid bilayer membrane which we demonstrate by using dye probes that are either covalently attached to one end of the oligonucleotide or reversibly bound by intercalation between the base pairs. Three cationic dyes, all strongly bound by intercalation to DNA when free in solution, are found to not bind to DNA but to prefer the membrane surface. The covalently attached Cy5 also binds to the bilayer while Cy3 tends to end-stack to the oligonucleotide duplex. The orientation of Cy5 parallel to the membrane indicates that electrostatic surface binding predominates over insertion into the hydrophobic interior of the membrane. Anionic and zwitterionic dyes (FAM and ROX) are found to remain randomly oriented in the water between the lipid bilayer surfaces. © The Royal Society of Chemistry.

  12. Orientating layers with adjustable pretilt angles for liquid crystals deposited by a linear atmospheric pressure plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Jian, Shih-Jie; Kou, Chwung-Shan [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Hwang, Jennchang [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lee, Chein-Dhau; Lin, Wei-Cheng [Material and Chemical Research Laboratories/Industrial Technology Research Institute, Hsinchu 30140, Taiwan (China)

    2013-06-15

    A method for controlling the pretilt angles of liquid crystals (LC) was developed. Hexamethyldisiloxane polymer films were first deposited on indium tin oxide coated glass plates using a linear atmospheric pressure plasma source. The films were subsequently treated with the rubbing method for LC alignment. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy measurements were used to characterize the film composition, which could be varied to control the surface energy by adjusting the monomer feed rate and input power. The results of LC alignment experiments showed that the pretilt angle continuously increased from 0 Degree-Sign to 90 Degree-Sign with decreasing film surface energy.

  13. Crystal violet: Study of the photo-fading of an early synthetic dye in aqueous solution and on paper with HPLC-PDA, LC-MS and FORS

    Energy Technology Data Exchange (ETDEWEB)

    Confortin, Daria; Brustolon, Marina; Franco, Lorenzo [Dipartimento di Scienze Chimiche, Universita degli Studi di Padova, via Marzolo 1, 35131 Padova (Italy); Neevel, Han; Bommel, Maarten R van [Netherlands Institute for Cultural Heritage (ICN), PO Box 76709, 1070 KA, Amsterdam (Netherlands); Kettelarij, Albert J; Williams, Rene M, E-mail: daria.confortin@gmail.co [Molecular Photonics Group, Van' t Hoff Institute for Molecular Sciences, Faculty of Science, Universiteit van Amsterdam, Nieuwe Achtergracht 129, 1018 WS Amsterdam (Netherlands)

    2010-06-01

    The photo-fading of crystal violet (CV), one of the earliest synthetic dyes and an ink component, is examined both in solution and on paper. Aqueous solutions of CV were exposed to UV light (365nm) and samples were taken at constant time intervals and analysed with a High Performance Liquid Chromatography-Photo Diode Array (HPLC-PDA) and Liquid Chromatography-Mass Spectroscopy (LC-MS). Demethylation products were positively identified. Also, deamination probably occurred. The oxidation at the central carbon likely generates Michler's ketone (MK) or its derivatives, but still needs confirmation. To study CV on paper, Whatman paper was immersed in CV and exposed to UV light. Before and after different irradiation periods, reflectance spectra were recorded with Fibre Optic Reflectance Spectrophotometry (FORS). A decrease in CV concentration and a change in aggregation type for CV molecules upon irradiation was observed. Colorimetric L*a*b* values before and during irradiation were also measured. Also, CV was extracted from paper before and after different irradiation periods and analysed with HPLC-PDA. Photo-fading of CV on paper produced the same products as in solution, at least within the first 100 hours of irradiation. Finally, a photo-fading of CV in the presence of MK on Whatman paper was performed. It was demonstrated that MK both accelerates CV degradation and is consumed during the reaction. The degradation pathway identified in this work is suitable for explaining the photo/fading of other dyes belonging to the triarylmethane group.

  14. Direct-writing of complex liquid crystal patterns.

    Science.gov (United States)

    Miskiewicz, Matthew N; Escuti, Michael J

    2014-05-19

    We report on a direct-write system for patterning of arbitrary, high-quality, continuous liquid crystal (LC) alignment patterns. The system uses a focused UV laser and XY scanning stages to expose a photoalignment layer, which then aligns a subsequent LC layer. We intentionally arrange for multiple overlapping exposures of the photoalignment material by a scanned Gaussian beam, often with a plurality of polarizations and intensities, in order to promote continuous and precise LC alignment. This type of exposure protocol has not been well investigated, and sometimes results in unexpected LC responses. Ultimately, this enables us to create continuous alignment patterns with feature sizes smaller than the recording beam. We describe the system design along with a thorough mathematical system description, starting from the direct-write system inputs and ending with the estimated alignment of the LC. We fabricate a number of test patterns to validate our system model, then design and fabricate a number of interesting well-known elements, including a q-plate and polarization grating.

  15. Soft and broadband infrared metamaterial absorber based on gold nanorod/liquid crystal hybrid with tunable total absorption

    Science.gov (United States)

    Su, Zhaoxian; Yin, Jianbo; Zhao, Xiaopeng

    2015-11-01

    We design a soft infrared metamaterial absorber based on gold nanorods dispersed in liquid crystal (LC) placed on a gold film and theoretically investigate its total absorption character. Because the nanorods align with the LC molecule, the gold nanorods/LC hybrid exhibits different permittivity as a function of tilt angle of LC. At a certain tilt angle, the absorber shows an omnidirectional total absorption effect. By changing the tilt angle of LC by an external electric field, the total absorption character can be adjusted. The total absorption character also depends on the concentration, geometric dimension of nanorods, and defect of nanorod arrangement in LC. When the LC contains different size of gold nanorods, a broadband absorption can be easily realized. The characteristics including flexibility, omnidirectional, broadband and tunablility make the infrared metamaterial absorber possess potential use in smart metamaterial devices.

  16. Coherent bremsstrahlung, coherent pair production, birefringence, and polarimetry in the 20–170 GeV energy range using aligned crystals

    Directory of Open Access Journals (Sweden)

    2008-04-01

    Full Text Available The processes of coherent bremsstrahlung (CB and coherent pair production (CPP based on aligned crystal targets have been studied in the energy range 20–170 GeV. The experimental arrangement allowed for measurements of single photon properties of these phenomena including their polarization dependences. This is significant as the theoretical description of CB and CPP is an area of active debate and development. With the approach used in this paper, both the measured cross sections and polarization observables are predicted very well. This indicates a proper understanding of CB and CPP up to energies of 170 GeV. Birefringence in CPP on aligned crystals is applied to determine the polarization parameters in our measurements. New technologies for high-energy photon beam optics including phase plates and polarimeters for linear and circular polarization are demonstrated in this experiment. Coherent bremsstrahlung for the strings-on-strings (SOS orientation yields a larger enhancement for hard photons than CB for the channeling orientations of the crystal. Our measurements and our calculations indicate low photon polarizations for the high-energy SOS photons.

  17. 侧链含稠环的新型聚酰亚胺液晶垂直取向剂的制备及表征%Preparation and Characterization of Novel Polyimide with Thick Ring in Side Chain for Vertical Alignment Liquid Crystals

    Institute of Scientific and Technical Information of China (English)

    郭春桔; 夏森林; 孙振; 汪映寒

    2012-01-01

    A novel functional diamine (H8-c) with thick ring and long alkoxy was synthesized from 3,5-dinitrobenzoyl chloride, estradiol and 1-Bromooctane. A polyimide (PI), applied in liquid crystal (LC) vertical orientation agent, was prepared from p-phenylenediamine (PDA), 1,2,3,4-cyclobutanetetracarboxylicdianhydride (CBDA) and H8-c. The PI possessed excellent vertical alignment for nematic LC. The vertical alignment of LC cell which was kept at 120 ℃ for 12 h was still stable. It could be seen that the thermal stability of the vertical alignment of LC was excellent. The temperature at 5% weight loss of the PI (T5) is as high as 400 ℃ in nitrogen. The temperature at 10% weight loss of the PI (T10) is as high as 480 ℃ in nitrogen. The PI film exhibited high transparency (95%) at wavelengths above 400 nm.%以3,5-二硝基苯甲酰氯、雌二醇及溴代正辛烷为原料合成了含有稠环结构的新型功能性二胺(H8-c).用1,2,3,4-环丁烷四甲酸二酐(CBDA)、对苯二胺(PDA)及H8-c共聚制备了一种聚酰亚胺(PI)液晶垂直取向剂.该PI膜作为取向层制得的液晶盒,在120℃下烘烤12 h仍可垂直取向,拥有良好的垂直取向热稳定性.热重分析(TGA)测试表明其具有良好的热稳定性,在氮气中,这种PI的5%热失重温度(T5)和10%热失重温度(T10)分别高达400℃和480℃.紫外可见光谱(UV-vis)显示此PI膜在400 nm以上具有高的透过率,可达95%以上.

  18. DNA hybridization-induced reorientation of liquid crystal anchoring at the nematic liquid crystal/aqueous interface.

    Science.gov (United States)

    Price, Andrew D; Schwartz, Daniel K

    2008-07-01

    Interactions between DNA and an adsorbed cationic surfactant at the nematic liquid crystal (LC)/aqueous interface were investigated using polarized and fluorescence microscopy. The adsorption of octadecyltrimethylammonium bromide (OTAB) surfactant to the LC/aqueous interface resulted in homeotropic (untilted) LC alignment. Subsequent adsorption of single-stranded DNA (ssDNA) to the surfactant-laden interface modified the interfacial structure, resulting in a reorientation of the LC from homeotropic alignment to an intermediate tilt angle. Exposure of the ssDNA/OTAB interfacial complex to its ssDNA complement induced a second change in the interfacial structure characterized by the nucleation, growth, and coalescence of lateral regions that induced homeotropic LC alignment. Fluorescence microscopy showed explicitly that the complement was colocalized in the same regions as the homeotropic domains. Exposure to noncomplementary ssDNA caused no such response, suggesting that the homeotropic regions were due to DNA hybridization. This hybridization occurred in the vicinity of the interface despite the fact that the conditions in bulk solution were such that hybridization did not occur (high stringency), suggesting that the presence of the cationic surfactant neutralized electrostatic repulsion and allowed for hydrogen bonding between DNA complements. This system has potential for label-less and portable DNA detection. Indeed, LC response to ssDNA target was detected with a lower limit of approximately 50 fmol of complement and was sufficiently selective to differentiate a one-base-pair mismatch in a 16-mer target.

  19. Effects of magnetic pre-alignment of nano-powders on formation of high textured barium hexa-ferrite quasi-single crystals via a magnetic forming and liquid participation sintering route

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Junliang, E-mail: liujunliang@yzu.edu.cn [Key Laboratory of Environmental Materials and Engineering of Jiangsu Province, School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Zeng, Yanwei [State Key Laboratory of Materials-Oriented Chemical Engineering, School of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China); Zhang, Xingkai [Key Laboratory of Environmental Materials and Engineering of Jiangsu Province, School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Zhang, Ming [Key Laboratory of Environmental Materials and Engineering of Jiangsu Province, School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Testing Center of Yangzhou University, Yangzhou 225002 (China)

    2015-05-15

    Highly textured barium hexa-ferrite quasi-single crystal with narrow ferromagnetic resonance line-width is believed to be a potential gyromagnetic material for self-biased microwave devices. To fabricate barium hexa-ferrite quasi-single crystal with a high grain orientation degree, a magnetic forming and liquid participation sintering route has been developed. In this paper, the effects of the pre-alignment of the starting nano-powders on the formation of barium quasi-single crystal structures have been investigated. The results indicated that: the crystallites with large sizes and small specific surfaces were easily aligned for they got higher driving forces and lower resistances during magnetic forming. The average restricting magnetic field was about 4.647 kOe to overcome the average friction barrier between crystallites. The pre-aligned crystallites in magnetic forming acted as the “crystal seeds” for oriented growth of the un-aligned crystallites during liquid participation sintering to achieve a high grain orientation. To effectively promote the grain orientation degrees of the sintered pellets, the grain orientation degrees of the green compacts must be higher than a limited value of 15.0%. Barium hexa-ferrite quasi-single crystal with a high grain orientation degree of 98.6% was successfully fabricated after sintering the green compact with its grain orientation degree of 51.1%. - Highlights: • Aligned particles acted as “crystal seeds” for un-aligned ones' oriented growth. • Magnetic field of 4.647 kOe was needed to overcome crystallites' friction barrier. • GOD dramatically increased after sintering if starting GOD exceeded to 15.0%. • Quasi-single crystal was prepared by sintering green compact with GOD of 51.1%.

  20. RF sputtering deposited a-IGZO films for LCD alignment layer application

    Science.gov (United States)

    Wu, G. M.; Liu, C. Y.; Sahoo, A. K.

    2015-11-01

    In this paper, amorphous indium gallium zinc oxide (a-IGZO) inorganic films were deposited at a fixed oblique angle using radio-frequency sputtering on indium tin oxide (ITO) glass as alternative alignment layer for liquid crystal displays. A series of experiments have been carried out to reveal the physical characteristics of the a-IGZO films, such as optical transmittance, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The special treatment a-IGZO films were used to fabricate liquid crystal (LC) cells and investigate the performances of these cells. Pretilt angles were measured with anti-parallel LC cells and voltage-transmittance (V-T) curve, contrast ratio, and response time were evaluated with optically compensated bend (OCB) LC cells. The electro-optical characteristics of the aligned homogenous LCs, and OCB mode cells based on the a-IGZO alignment layer were compared to those based on rubbing processed polyimide (PI). The results showed that the average transmittance in the visible wavelength range was higher than 90% for the a-IGZO alignment layer. The LC pretilt angle has been determined at about 6°. The evaluted cell critical voltage at maximum transmittance was 1.8 V, lower than the control cell using PI alignment layer. The OCB cell rise time and fall time were 1.55 ms and 3.49 ms, respectivly. A very quick response time of 5.04 ms has thus been achived. In addition, the study of V-T characteristics suggested higher contrast ratio for LCD display applications.

  1. Far-Field Patterns from Dye-Doped Planar-Aligned Nematic Liquid Crystals Under nanosecond Laser Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lukishova, S.G.; Lepeshkin, N.; Boyd, R.W.; Marshall, K.L.

    2006-08-18

    High-definition patterns were observed under 10-Hz-pulse-repetition-rate, nanosecond laser irradiation of azodye-doped planar-nematic liquid crystal layers at incident intensities I ~ 5-10 MW/cm^2 in a single beam configuration and without any feedback involved. An incident polarization parallel to the nematic director was used. Under periodic pulsed laser irradiation, far-field beam patterns at the output of a dye-doped liquid crystal layer changed kaleidoscopically from rings and stripes to multiple hexagons. This pattern-formation regime had a buildup time of several seconds to minutes. We explain the observed effect by diffraction of the laser beam on light-induced micrometer-size inhomogeneities inside the liquid crystal layer with absorption and refraction properties different from the surrounding area. Possible mechanisms of the formation of the inhomogeneities are discussed.

  2. Enhanced electromagnetic showers initiated by 20-180 GeV gamma rays on aligned thick germanium crystals

    Energy Technology Data Exchange (ETDEWEB)

    Baurichter, A.; Kirsebom, K.; Medenwaldt, R.; Mikkelsen, U.; Moeller, S.P.; Uggerhoej, E.; Worm, T.; Kononets, Y.V.; Elsener, K.; Ballestrero, S.; Sona, P.; Biino, C.; Connell, S.H.; Sellschop, J.P.F.; Vilakazi, Z.Z.; Apyan, A.; Avakian, R.O.; Ispirian, K.A.; Taroian, S.P

    1999-06-01

    The distribution of the energy released in a silicon detector placed on the downstream side of thick germanium single crystals bombarded by 20-180 GeV gamma rays along directions close to the <1 1 0> axis or along a random direction has been investigated. A large enhancement of the shower for axial incidence of the gamma rays has been found. The response of the system composed of a germanium crystal and a silicon detector to single gamma rays as a function of their energy has been deduced and compared with existing Monte Carlo simulations.

  3. Enhanced electromagnetic showers initiated by 20-180 GeV gamma rays on aligned thick germanium crystals

    Science.gov (United States)

    Baurichter, A.; Kirsebom, K.; Medenwaldt, R.; Mikkelsen, U.; Møller, S. P.; Uggerhøj, E.; Worm, T.; Kononets, Y. V.; Elsener, K.; Ballestrero, S.; Sona, P.; Biino, C.; Connell, S. H.; Sellschop, J. P. F.; Vilakazi, Z. Z.; Apyan, A.; Avakian, R. O.; Ispirian, K. A.; Taroian, S. P.

    1999-06-01

    The distribution of the energy released in a silicon detector placed on the downstream side of thick germanium single crystals bombarded by 20-180 GeV gamma rays along directions close to the axis or along a random direction has been investigated. A large enhancement of the shower for axial incidence of the gamma rays has been found. The response of the system composed of a germanium crystal and a silicon detector to single gamma rays as a function of their energy has been deduced and compared with existing Monte Carlo simulations.

  4. Near-Field Birefringence Response of Liquid Crystal Molecules in Thickness Direction of Liquid Crystal Thin Film Orientated by Shear Force

    Institute of Scientific and Technical Information of China (English)

    Jing QIN; Norihiro UMEDA

    2007-01-01

    Information of molecular orientation in nematic liquid crystal (LC) is attractive and important for applications in the field of display devices. We demonstrate a novel method using a birefringence scanning near-field optical microscope (Bi-SNOM) with a probe which is inserted into the LC thin film to detect the molecular orientation from its birefringence responses in the thickness direction of the LC thin film. The probe is laterally vibrated when going forward into the LC thin film, and the retardation and azimuth angle are recorded as the probe going down. Firstly, the thickness of the LC thin film is measured by the shear force detection. Since the shear force acts as a stimulation to reorientate the LC molecules above the substrate surface, we can detect the molecular orientation caused by a polyimide alignment substrate and the effect to molecular orientation caused by vibration of fibre probe. As a result, the orientation profiling of the LC film in depth direction is obtained in both the cases that the direction of probe vibrating is vertical/parallel to the rubbing direction of the alignment film.Furthermore, the thickness of completely orientated layers just above the substrate surface can also be obtained by either vibrating probe or no-vibrating probe. Ultimately, the LC thin film can be modelled in thickness direction from all the results using this method.

  5. Computational aspects of the smectization process in liquid crystals: An example study of a perfectly aligned two-dimensional hard-boomerang system

    Science.gov (United States)

    Chrzanowska, Agnieszka

    2017-06-01

    A replica method for calculation of smectic liquid crystal properties within the Onsager theory has been presented and applied to an exemplary case of two-dimensional perfectly aligned needlelike boomerangs. The method allows one to consider the complete influence of the interaction terms in contrast to the Fourier expansion method which uses mostly first or second order terms of expansion. The program based on the replica algorithm is able to calculate a single representative layer as an equivalent set of layers, depending on the size of the considered width of the sample integration interval. It predicts successfully smectic density distributions, energies, and layer thicknesses for different types of layer arrangement—of the antiferroelectric or of the smectic A order type. Specific features of the algorithm performance and influence of the numerical accuracy on the physical properties are presented. Future applications of the replica method to freely rotating molecules are discussed.

  6. A perfectly aligned 63 helical tubular cuprous bromide single crystal for selective photo-catalysis, luminescence and sensing of nitro-explosives.

    Science.gov (United States)

    Yao, Ru-Xin; Hailili, Reshalaiti; Cui, Xin; Wang, Li; Zhang, Xian-Ming

    2015-02-21

    A perfectly aligned 63 helical tubular cuprous bromide single crystal has been synthesized and characterized, which can selectively decompose negatively charged dyes of Methyl Orange (MO) and Kermes Red (KR), and the photocatalytic efficiency is higher than that of nanosized (∼25 nm) TiO2 and ZnO. The direction and magnitude of the dipole moments as well as the band structure were calculated to reveal high photocatalytic efficiency. Moreover, luminescence studies indicate that the CuBr tube materials show very strong yellowish green emissions in the solid state and emulsion even at room temperature, and exhibit extremely high detection sensitivity towards nitro-explosives via fluorescence quenching. Detectable luminescence responses were observed at a very low concentration of 20 ppm with a high quenching efficiency of 94.90%. The results suggest that they may be promising multifunctional materials for photo-catalysis, luminescence and sensing of nitro-explosives.

  7. Graphene oxide liquid crystals as a versatile and tunable alignment medium for the measurement of residual dipolar couplings in organic solvents.

    Science.gov (United States)

    Lei, Xinxiang; Xu, Zhen; Sun, Han; Wang, Shun; Griesinger, Christian; Peng, Li; Gao, Chao; Tan, Ren X

    2014-08-13

    Residual dipolar couplings (RDCs) have proven to be an invaluable anisotropic NMR parameter for the structural elucidation of complex biopolymers and organic molecules. However, a remaining bottleneck limiting its wider use by organic and natural product chemists is the lack of a range of easily applicable aligning media for diverse organic solvents. In this study, graphene oxide (GO) liquid crystals (LCs) were developed to induce partial orientation of organic molecules to allow RDC measurements. These LCs were determined to be maintainable at very low concentrations (as low as 1 mg/mL, corresponding to quadrupolar (2)H splittings ranging from 2.8 to 30 Hz and maximum (13)C-(1)H dipolar couplings of 20 Hz for camphor in a CH3COCH3/water system) and to be remarkably stable and broadly compatible with aqueous and organic solvents such as dimethyl sulfoxide, CH3COCH3, and CH3CN. Moreover, compared with those for other alignment media, very clean and high-quality NMR spectra were acquired with the GO molecules in solution because of their rigidity and high molecular weight. The developed medium offers a versatile and robust method for RDC measurements that may routinize the RDC-based structure determination of organic molecules.

  8. Disodium cromoglycate: exploiting its properties as a NMR weak-aligning medium for small organic molecules.

    Science.gov (United States)

    Troche-Pesqueira, Eduardo; Cid, María-Magdalena; Navarro-Vázquez, Armando

    2014-03-28

    Chromonic phases are a family of lyotropic liquid crystals (LC) formed by ionic aromatic mesogens such as disodium cromoglycate (cromolyn), sunset yellow and others. It is well known that chromonic phases are oriented in the presence of external magnetic fields, leading to the observation of anisotropic NMR observables such as quadrupolar splittings or residual dipolar couplings. Despite the fact that the cromolyn nematic LC phase (N) presents important advantages like great homogeneity, small line broadening, and easy sample preparation, it has been scarcely used as a water-compatible NMR orienting medium, in part due to a too strong induced degree of alignment on the guest molecules. However, the use of cromolyn-brine mixtures led to the optimum degree of alignment allowing to record (1)H-(13)C dipolar couplings with good accuracy.

  9. Electro-optical characteristics of a chiral hybrid in-plane switching liquid crystal mode for high brightness.

    Science.gov (United States)

    Gwag, Jin Seog; Sohn, Kyunghwa; Kim, Young-Ki; Kim, Jae-Hoon

    2008-08-04

    We propose a new in-plane switching (IPS) nematic liquid crystal (LC) mode which uses a twist effect with a hybrid LC alignment and interdigitated electrodes as an approach for a high brightness. This is optimized to a normally white mode to minimize loss of transmittance at the electrode compared to the conventional IPS mode. The proposed mode shows an excellent dark state because the bulk LCs are aligned in parallel to the optic axis of the polarizer under low electric fields. Consequently, this proposed mode exhibits a much higher contrast ratio (980:1) than that of the conventional IPS mode (550:1).

  10. Liquid crystal devices based on photoalignment and photopatterning materials

    Science.gov (United States)

    Chigrinov, Vladimir

    2014-02-01

    Liquid crystal (LC) display and photonics devices based on photo-alignment and photo-patterning LC cells are developed. A fast switchable grating based on ferroelectric liquid crystals and orthogonal planar alignment by means of photo alignments. Both 1D and 2D gratings have been constructed. The proposed diffracting element provides fast response time of around 20 μs, contrast of 7000:1 and high diffraction efficiency, at the electric field of 6V/μm. A switchable LC Fresnel zone lens was also developed with the efficiency of ~42% that can be further improved, and the switching time for the 3 μm thick cell is ~6.7 ms which is relatively fast in comparison of existing devices. Thus, because of the photoalignment technology the fabrication of Fresnel lens became considerably simpler than others. A thin high spatial resolution, photo-patterned micropolarizer array for complementary metal-oxide-semiconductor (CMOS) image sensors was implemented for the complete optical visualization of so called "invisible" objects, which are completely transparent (reflective) and colorless. Four Stokes parameters, which fully characterized the reflected light beam can be simultaneously detected using the array of photo-patterned polarizers on CMOS sensor plate. The cheap, high resolution photo-patterned LC matrix sensor was developed to be able successfully compete with the expensive and low reliable wire grid polarizer patterned arrays currently used for the purpose.

  11. Effects of Side Chains with Similar Lengths and Different Structures of Polyimides on Liquid Crystal Alignment Behavior

    Institute of Scientific and Technical Information of China (English)

    Jia-hao Xia; Ying Jiang; Shi-ming Gong; Zhen Sun; Ying-han Wang

    2014-01-01

    Polyimides (PI) with different side chains in structure were synthesized by copolycondensation of pyromelliticmdianhydride (PMDA) with 3,5-diamino-(4'-methane acid hexyl ester) phenyl-benzamide (C6-PDA),(4-butoxybiphenol)-3',5'-diaminobenzoate (C4-BBDA) and 3,5-diamino-benzoic acid decyl ester (C 10-DA) named PI-PDA,PI-C4,PI-DA,respectively.The lengths of side chains of PI-PDA and PI-DA are as similar as that of PI-C4.Through the pretilt angle tests it is demonstrated that neither the structure of side chains nor the rubbing process could make an obvious difference on vertical alignment property when the lengths of the side chains are similar,standing at around 1.6 nm.The measurement of surface energy of PI surfaces further proved this result.The result of the X-ray photo-electron spectroscope measurement indicated that the side chains of PIs stretched out from the polymer bulk phase and accumulated on the surface.

  12. Controlled transition dipole alignment of energy donor and energy acceptor molecules in doped organic crystals, and the effect on intermolecular Förster energy transfer.

    Science.gov (United States)

    Wang, Huan; Yue, Bailing; Xie, Zengqi; Gao, Bingrong; Xu, Yuanxiang; Liu, Linlin; Sun, Hongbo; Ma, Yuguang

    2013-03-14

    The orientation factor κ(2) ranging from 0 to 4, which depends on the relative orientation of the transition dipoles of the energy donor (D) and the energy acceptor (A) in space, is one of the pivotal factors deciding the efficiency and directionality of resonance energy transfer (RET) in a D-A molecular system. In this work, tetracene (Tc) and pentacene (Pc) are successfully doped in a trans-1,4-distyrylbenzene (DSB) crystalline lattice to form definite D-A mutually perpendicular transition dipole orientations. The cross D-A dipole arrangement results in an extremely small orientation factor, which is about two orders smaller than that in the disordered films. The energy transfer properties from the host (DSB) to the guest (Tc/Pc) were investigated in detail by steady-state as well as time-resolved fluorescence spectroscopy. Our experimental research results show that the small value of κ(2) allows less or partial energy transfer from the host (DSB) to the guest (Tc) in a wide range of guest concentration, with the Förster distance of around 1.5 nm. By controlling the doping concentrations in the Tc and Pc doubly doped DSB crystals, we demonstrate, as an example, for the first time the application of the restricted energy transfer by D-A cross transition dipole arrangement for preparation of a large-size, white-emissive organic crystal with the CIE coordinates of (0.36, 0.37) approaching an ideal white light. In contrast, Tc is also doped in an anthracene crystalline lattice to form head-to-tail D-A transition dipole alignment, which is proved to be highly effective to promote the intermolecular energy transfer. In this doped system, the orientation factor is relatively large and the Förster distance is around 7 nm.

  13. RF sputtering deposited a-IGZO films for LCD alignment layer application

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-01

    Highlights: • a-IGZO nanolayer has been presented for alignment of liquid crystals in LCD. • RF sputtering deposition at an oblique angle has been performed to grow the films. • High transparency over 90% was obtained in the visible wavelength range. • The OCB cells exhibited fast on-off and short response time of 5.04 ms. • V–T characteristics proved high contrast ratio for LCD display applications. - Abstract: In this paper, amorphous indium gallium zinc oxide (a-IGZO) inorganic films were deposited at a fixed oblique angle using radio-frequency sputtering on indium tin oxide (ITO) glass as alternative alignment layer for liquid crystal displays. A series of experiments have been carried out to reveal the physical characteristics of the a-IGZO films, such as optical transmittance, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The special treatment a-IGZO films were used to fabricate liquid crystal (LC) cells and investigate the performances of these cells. Pretilt angles were measured with anti-parallel LC cells and voltage–transmittance (V–T) curve, contrast ratio, and response time were evaluated with optically compensated bend (OCB) LC cells. The electro-optical characteristics of the aligned homogenous LCs, and OCB mode cells based on the a-IGZO alignment layer were compared to those based on rubbing processed polyimide (PI). The results showed that the average transmittance in the visible wavelength range was higher than 90% for the a-IGZO alignment layer. The LC pretilt angle has been determined at about 6°. The evaluted cell critical voltage at maximum transmittance was 1.8 V, lower than the control cell using PI alignment layer. The OCB cell rise time and fall time were 1.55 ms and 3.49 ms, respectivly. A very quick response time of 5.04 ms has thus been achived. In addition, the study of V–T characteristics suggested higher contrast ratio for LCD display applications.

  14. Coherent Bremsstrahlung, Coherent Pair Production, Birefringence and Polarimetry in the 20-170 GeV energy range using aligned crystals

    CERN Document Server

    Apyan, A; Badelek, B; Ballestrero, S; Biino, C; Birol, I; Cenci, P; Connell, S H; Eichblatt, S; Fonseca, T; Freund, A; Gorini, B; Groess, R; Ispirian, K; Ketel, T; Kononets, Y V; López, A; Mangiarotti, A; Sellschop, J P Friedel; Shieh, M; Sona, P; Strakhovenko, V M; Uggerhøj, U; Uggerhøj, Erik; Van Rens, B; Velasco, M; Vilakazi, Z Z; Wessely, O; Ünel, G; Kononets, Yu V

    2008-01-01

    The processes of coherent bremsstrahlung (CB) and coherent pair production (CPP) based on aligned crystal targets have been studied in the energy range 20-170 GeV. The experimental arrangement allowed these phenomena as well as their polarization dependence to be evaluated under conditions where single-photon cross-sections could be measured. This proved very important as the theoretical description of CB and CPP is an area of active theoretical debate and development. The theoretical approach used in this paper predicts both the cross sections and polarization observables very well for the experimental conditions investigated, indicating that the understanding of CB and CPP is reliable up to energies of 170 GeV. A birefringence effect in CPP was studied and it was demonstrated this enabled new technologies for high energy photon beam optics, such as polarimeters (for both linear and circular polarization) and phase plates. We also present new results regarding the features of coherent high energy photon emis...

  15. Touch sensors based on planar liquid crystal-gated-organic field-effect transistors

    Science.gov (United States)

    Seo, Jooyeok; Lee, Chulyeon; Han, Hyemi; Lee, Sooyong; Nam, Sungho; Kim, Hwajeong; Lee, Joon-Hyung; Park, Soo-Young; Kang, Inn-Kyu; Kim, Youngkyoo

    2014-09-01

    We report a tactile touch sensor based on a planar liquid crystal-gated-organic field-effect transistor (LC-g-OFET) structure. The LC-g-OFET touch sensors were fabricated by forming the 10 μm thick LC layer (4-cyano-4'-pentylbiphenyl - 5CB) on top of the 50 nm thick channel layer (poly(3-hexylthiophene) - P3HT) that is coated on the in-plane aligned drain/source/gate electrodes (indium-tin oxide - ITO). As an external physical stimulation to examine the tactile touch performance, a weak nitrogen flow (83.3 μl/s) was employed to stimulate the LC layer of the touch device. The LC-g-OFET device exhibited p-type transistor characteristics with a hole mobility of 1.5 cm2/Vs, but no sensing current by the nitrogen flow touch was measured at sufficiently high drain (VD) and gate (VG) voltages. However, a clear sensing current signal was detected at lower voltages, which was quite sensitive to the combination of VD and VG. The best voltage combination was VD = -0.2 V and VG = -1 V for the highest ratio of signal currents to base currents (i.e., signal-to-noise ratio). The change in the LC alignment upon the nitrogen flow touch was assigned as the mechanism for the present LC-g-OFET touch sensors.

  16. Shape evolution of a single liquid-crystal droplet immersed in an isotropic matrix under transient and steady flow

    Science.gov (United States)

    Wu, Youjun; Yu, Wei; Zhou, Chixing; Xu, Yuanze

    2007-04-01

    The morphology evolution of immiscible polymer-liquid crystal systems is quite different from flexible polymer-polymer mixtures due to the anisotropic properties of liquid crystals. The deformation and retraction of a single low molar mass liquid crystal 4' -pentyl-4-biphenylcarbonitrile (5CB) droplet and 4' -octyl-4-biphenylcarbonitrile (8CB) dispersed in polydimethyl-siloxane under two-dimensional linear flow was investigated by a computer-controlled four-roll mill, which is equipped with an optical microscope and a digital camera. The deformation parameter and orientation angle during deformation versus capillary number was obtained and compared with calculations using the Maffettone-Minale (MM) model and the Yu-Zhou liquid-crystal (YZ-LC) model. The MM model can describe the behavior of a Newtonian droplet in another Newtonian matrix whereas the YZ-LC model can describe the behavior of a LC droplet in a Newtonian matrix. The results showed that the deformation and rotation of a LC droplet is more difficult than viscoelastic droplets, possibly because of the resistance of the nematic elastic energy induced by the nematic mesogens deformation and orientation under flow field. Furthermore, the different behavior between flow-aligning 5CB and flow-tumbling 8CB droplets and the influence of droplet size of LC on deformation and retraction were discussed by experiment and calculation; the results reveal that the different size LC droplets show different evolution curves.

  17. Direct nanomechanical measurement of layer thickness and compressibility of smectic liquid crystals.

    Science.gov (United States)

    Carbone, Giovanni; Zappone, Bruno; Barberi, Riccardo; Bartolino, Roberto; Musevic, Igor

    2011-05-01

    Using an atomic force microscope (AFM) we confined a smectic-A liquid crystal (LC) between a flat glass plate and a 10-μm glass sphere attached to the free end of the AFM cantilever. Both surfaces were treated with a surfactant that induces normal alignment of the LC molecules. We measured the force F acting on the cantilever while varying the plate-sphere distance D with subnanometer precision. For D thickness a(0) and compressibility modulus B. Compared to other techniques used to determine a(0) and B, AFM measurements are faster and require a much smaller amount (microliters) of LC. Moreover, they are based on purely mechanical deformations of the LC structure and do not require any static or radiative electromagnetic field.

  18. A single-gap transflective liquid crystal driven by fringe and vertical electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Young Jin; Chin, Mi Hyung; Kim, Jin Ho; Her, Jung Hwa; Lee, Seung Hee [Polymer BIN Fusion Research Center, Department of Polymer Nano-Science and Technology, Chonbuk National University, Chonju, Chonbuk 561-756 (Korea, Republic of); Jin, Hyun Suk; Kim, Byeong Koo, E-mail: lsh1@chonbuk.ac.k [Mobile Product Development Department, LG Display Co., Ltd., Gumi, Gyungbuk 730-350 (Korea, Republic of)

    2009-07-21

    A single-gap transflective liquid-crystal display driven by a fringe electric field in the transmissive (T) region and a vertical electric field in the reflective (R) region was designed. In the device, a homogeneously aligned liquid crystal (LC) rotates almost in plane by a fringe field in the T-region whereas the LC tilts upwards by a vertical field in the R-region. A high surface pre-tilt angle of the LC in the R-region is achieved through polymerization of an UV curable reactive mesogen monomer at the surfaces and thus the effective cell retardation in the R-region becomes half of that in the T-region. Consequently, a transflective display driven by a vertical and a fringe electric field with a single cell gap and single gamma curves is realized.

  19. Laser beam propagation in nematic liquid crystals at the temperature close to the nematicisotropic critical point.

    Science.gov (United States)

    Chen, Yu-Jen; Lin, Yu-Sung; Jiang, I-Min; Tsai, Ming-Shan

    2008-03-17

    This study investigates the optical nonlinearity of beam propagation in homogeneously aligned nematic liquid crystal (NLC) cells at a temperature close to the nematic-isotropic temperature (TNI). The undulate propagation mode with convergent and divergent loops appearing alternately is reported and the thermally enhanced optical reorientation nonlinearity at the focus is described. The optically induced phase transition exists along the pump beam direction. With the application of the conscopic technique, the arrangements of LC at the focus are proposed in this study. Results of this study demonstrate that the evolution of the LC configuration was affected by the pump beam based on the analysis of conoscopic patterns.

  20. Fabrication of liquid crystal based sensor for detection of hydrazine vapours

    Science.gov (United States)

    Nandi, Rajib; Singh, Sachin Kumar; Singh, Hemant Kumar; Singh, Bachcha; Singh, Ranjan K.

    2014-10-01

    A novel liquid crystal (LC) based sensor to detect trace level amount of hydrazine vapour has been developed. The LC 4‧-pentyl-4-biphenylcarbonitrile (5CB) doped with 0.5 wt% 4-decyloxy benzaldehyde (DBA) shows dark to bright optical texture upon exposure of hydrazine vapours as revealed by polarizing optical microscopy under crossed polarizers. The hydrazine interacts with the doped DBA and form diimine compound which disrupt the orientation of aligned 5CB. The interaction between DBA and hydrazine has been also studied by Raman spectroscopy.

  1. Fast-response liquid crystal display by the VA-IPS display mode with nematic liquid crystal and polymer networks

    Science.gov (United States)

    Chen, Tien-Jung; Lin, Guan-Jhong; Chen, Bo-Yu; Wu, Jin-Jei; Yang, Ying-Jay

    2012-10-01

    To improve electrooptical characteristics of the vertical aligned (VA) liquid crystal displays (LCDs), the monomer material and in-plane switching (IPS) field produced by interdigital electrodes are employed in LC cells. The fast switching response and well optical transmittance of the VA-IPS display mode are successfully achieved by mixing the nematic LC with polymer networks, attributed to the surface anchoring, and the molecular orientation of the LC cell will be further governed, especially under the greater applied voltage. Furthermore, the high concentration doping of the monomer can effectively improve the response behavior, but it also results in the transmittance sacrificed due to the light scattering, and the threshold voltage (Vth) increased.

  2. Alignment validation

    Energy Technology Data Exchange (ETDEWEB)

    ALICE; ATLAS; CMS; LHCb; Golling, Tobias

    2008-09-06

    The four experiments, ALICE, ATLAS, CMS and LHCb are currently under constructionat CERN. They will study the products of proton-proton collisions at the Large Hadron Collider. All experiments are equipped with sophisticated tracking systems, unprecedented in size and complexity. Full exploitation of both the inner detector andthe muon system requires an accurate alignment of all detector elements. Alignmentinformation is deduced from dedicated hardware alignment systems and the reconstruction of charged particles. However, the system is degenerate which means the data is insufficient to constrain all alignment degrees of freedom, so the techniques are prone to converging on wrong geometries. This deficiency necessitates validation and monitoring of the alignment. An exhaustive discussion of means to validate is subject to this document, including examples and plans from all four LHC experiments, as well as other high energy experiments.

  3. Aligned Layers of Silver Nano-Fibers

    Directory of Open Access Journals (Sweden)

    Andrii B. Golovin

    2012-02-01

    Full Text Available We describe a new dichroic polarizers made by ordering silver nano-fibers to aligned layers. The aligned layers consist of nano-fibers and self-assembled molecular aggregates of lyotropic liquid crystals. Unidirectional alignment of the layers is achieved by means of mechanical shearing. Aligned layers of silver nano-fibers are partially transparent to a linearly polarized electromagnetic radiation. The unidirectional alignment and density of the silver nano-fibers determine degree of polarization of transmitted light. The aligned layers of silver nano-fibers might be used in optics, microwave applications, and organic electronics.

  4. Optimization of a Liquid Crystal-based Sensory Platform for Monitoring Enzymatic Glucose Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Yibin; Jang, Chang-Hyun [Gachon University, Seongnam (Korea, Republic of)

    2016-05-15

    Managing glucose levels in human blood is extremely important for the treatment of diabetes. Here, an innovative sensory strategy has been developed to monitor the enzymatic activities of glucose and glucose oxidase by using confined liquid crystal (LC) birefringent droplet patterns. Acidic products released during the glucose oxidation process lead to a slight decrease in the pH of aqueous systems that can be monitored by pH-sensitive LC materials. Of the existing pH-sensitive LC materials, dodecanoic acid-doped 4-cyano-4'-pentylbiphenyl is inexpensive and easily adjusted to satisfy the 7.4 ± 0.05 pH requirement of human blood. Moreover, the orientational alignment of capillary-confined pH-responsive LCs can be disrupted at the aqueous/LC interface following a slight decrease in the critical pH of aqueous reaction systems, which results in an optical signal that can be observed with the naked eye by using polarizing optical microscopy. Based on the stable LC droplet patterns generated by the cylindrical confinement system, the functionalized LCs can selectively detect glucose at concentrations as low as 0.1 pM. This study further advances the previously reported LC-based glucose monitoring systems by reducing production costs and instituting a smarter LC sensory design. This improved system shows potential for the use in clinical bioassay applications.

  5. Beyond Alignment

    DEFF Research Database (Denmark)

    Beyond Alignment: Applying Systems Thinking to Architecting Enterprises is a comprehensive reader about how enterprises can apply systems thinking in their enterprise architecture practice, for business transformation and for strategic execution. The book's contributors find that systems thinking...... is a valuable way of thinking about the viable enterprise and how to architect it....

  6. Domain Structures in Nematic Liquid Crystals on a Polycarbonate Surface

    Directory of Open Access Journals (Sweden)

    Vasily F. Shabanov

    2013-08-01

    Full Text Available Alignment of nematic liquid crystals on polycarbonate films obtained with the use of solvents with different solvations is studied. Domain structures occurring during the growth on the polymer surface against the background of the initial thread-like or schlieren texture are demonstrated. It is established by optical methods that the domains are stable formations visualizing the polymer surface structures. In nematic droplets, the temperature-induced transition from the domain structure with two extinction bands to the structure with four bands is observed. This transition is shown to be caused by reorientation of the nematic director in the liquid crystal volume from the planar alignment to the homeotropic state with the pronounced radial configuration of nematic molecules on the surface. The observed textures are compared with different combinations of the volume LC orientations and the radial distribution of the director field and the disclination lines at the polycarbonate surface.

  7. 侧链密度对聚酰亚胺取向膜性能的影响%Effect of Side Chain Density of Polyimides on Properties of Liquid Crystal Alignment Film

    Institute of Scientific and Technical Information of China (English)

    刘明; 孙振; 汪映寒

    2013-01-01

    4-dodecyloxy-phenyl-4',4"-diaminotriphenylamine (DPDTA) containing triphenylamine were successfully synthesized. Polyimides (PIs) containing triphenylamine units in the main chain were synthesized with the co-condensation of DMMDA,DPDTA and aromatic dianhydride 4 ,4'- oxydiphthalic anhydride (ODPA) by thermal imidization. The structures of the PIs were confirmed by FT-IR. The alignment behavior of PIs as liquid crystal alignment layers was also examined with polarized optical micrograph (POM). The properties of the PIs were characterized by TGA,UV-Vis and DSC etc. It was found that side chain density of PIs had important influence on properties of liquid crystal alignment film. Before rubbing,PI containing 25% DPDTA could induce uniform vertical alignment and a pretilt angle of 89. 7°. The liquid crystal was not aligned on the surface of PI film which contained 10% DPDTA without the rubbing treatment. After the rubbing process,the pretilt angle of liquid crystal was 2. 4,when PI film contained 25% DPDTA and the pretilt angle of liquid crystal was 1. 8% when PI contained 10% DPDTA. The transmittances of the Pis in 500~800 nm wavelengths are more than 80%,and their glass transition temperatures are above 230 ℃.%成功地合成了二胺单体十二烷氧基苯-4',4"-二氨基三苯胺(DPDTA),并用此单体与3,3′-二甲基-4,4'-二氨基二苯甲烷(DMMDA)和二苯醚四羧酸二酐(ODPA)共缩聚,采用低温缩聚-热酰亚胺化、通过调节共聚物组成制备了2种聚酰亚胺(PI).利用FT-IR、NMR、UV-Vis与DSC等手段对合成二胺单体及PI进行了结构表征和性能测试.研究了其取向性能、透光性能和耐热性能.结果表明,在摩擦前,含10% DPDTA的PI不能诱导液晶分子取向,含25%DPDTA的PI能诱导液晶分子垂直取向,预倾角可达89.6..而摩擦后,两种PI都能使液晶分子平行取向,预倾角分别为1.8°和2.4°.两种PI膜在500~800 nm区域透光率都在80

  8. Nonlinear optical studies of liquid crystals and polymers

    Science.gov (United States)

    Hong, Seok-Cheol

    Polymers are indispensable in our life. A life is a continuous event maintained by many complex processes in which biological polymers participate. It also gets help from a variety of natural and synthetic polymers with useful functions. Such functions depend on the chemical and conformational structures of polymers and often largely on the surface structures and properties of polymers. We used second order nonlinear optical techniques (sum frequency vibrational spectroscopy (SFVS) and second harmonic generation (SHG)) to obtain structural information on polymers. We also studied liquid crystal molecules deposited on polymer surfaces. The first part of the thesis is aimed at understanding liquid crystal (LC) alignment on rubbed polymer surfaces by determining the molecular orientations of LC adsorbates and surface polymer chains. The alignment of LCs by rubbed polymers is not only of fundamental interest but also of practical importance because it is a technique enabling production of commercial liquid crystal displays. We observed that rubbing induces alignment of surface polymer chains along the rubbing direction, and there is a strong correlation between the molecular orientations of LC adsorbates and the surface chains of rubbed polymers such as polyvinyl alcohol (PVA) and polyimide (6FDA-6CBO). The latter revealed a relatively large but negative pretilt angle, which is highly unusual. On a rubbed polystyrene (PS) surface, we found that the phenyl side groups of PS are oriented perpendicularly to the rubbing direction at the surface, rendering an LC alignment also perpendicular to the rubbing direction. The second part of the thesis is our discovery of rubbing-induced polar ordering on nylon 11 surfaces. Nylon 11 is known to be ferroelectric. We found that mechanical rubbing can induce strong ferroelectric polarization on an initially amorphous film of nylon 11. The surface chains of rubbed nylon 11 are aligned along the rubbing direction while the induced

  9. Shape-Selectivity with Liquid Crystal and Side-Chain Liquid Crystalline Polymer SAW Sensor Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    FRYE-MASON,GREGORY CHARLES; OBORNY,MICHAEL C.; PUGH,COLEEN; RICCO,ANTONIO; THOMAS,ROSS C.; ZELLERS,EDWARD T.; ZHANG,GUO-ZHENG

    1999-09-23

    A liquid crystal (LC) and a side-chain liquid crystalline polymer (SCLCP) were tested as surface acoustic wave (SAW) vapor sensor coatings for discriminating between pairs of isomeric organic vapors. Both exhibit room temperature smectic mesophases. Temperature, electric-field, and pretreatment with self-assembled monolayers comprising either a methyl-terminated or carboxylic acid-terminated alkane thiol anchored to a gold layer in the delay path of the sensor were explored as means of affecting the alignment and selectivity of the LC and SCLCP films. Results for the LC were mixed, while those for the SCLCP showed a consistent preference for the more rod-like isomer of each isomer pair examined.

  10. Active terahertz metamaterials based on liquid-crystal induced transparency and absorption

    Science.gov (United States)

    Yang, Lei; Fan, Fei; Chen, Meng; Zhang, Xuanzhou; Chang, Sheng-Jiang

    2017-01-01

    An active terahertz (THz) liquid crystal (LC) metamaterial has been experimentally investigated for THz wave modulation. Some interesting phenomena of resonance shifting, tunable electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA) have been observed in the same device structure under different DC bias directions and different incident wave polarization directions by the THz time domain spectroscopy. Further theoretical studies indicate that these effects originate from interference and coupling between bright and dark mode components of elliptically polarized modes in the LC metamaterial, which are induced by the optical activity of LC alignment controllable by the electric field as well as the changes of LC refractive index. The LC layer is indeed a phase retarder and polarization converter that is controlled by the DC bias. The THz modulation depth of the analogs of EIT and EIA effects are 18.3 dB and 10.5 dB in their frequency band, respectively. Electrical control, large modulation depth and feasible integration of this LC device make it an ideal candidate for THz tunable filter, intensity modulator and spatial light modulator.

  11. Touch sensors based on planar liquid crystal-gated-organic field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jooyeok; Lee, Chulyeon; Han, Hyemi; Lee, Sooyong; Nam, Sungho; Kim, Youngkyoo, E-mail: ykimm@knu.ac.kr [Organic Nanoelectronics Laboratory, Department of Chemical Engineering and Graduate School of Applied Chemical Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Kim, Hwajeong [Organic Nanoelectronics Laboratory, Department of Chemical Engineering and Graduate School of Applied Chemical Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Priority Research Center, Research Institute of Advanced Energy Technology, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Lee, Joon-Hyung [School of Materials Science and Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Park, Soo-Young; Kang, Inn-Kyu [Department of Polymer Science and Engineering and Graduate School of Applied Chemical Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of)

    2014-09-15

    We report a tactile touch sensor based on a planar liquid crystal-gated-organic field-effect transistor (LC-g-OFET) structure. The LC-g-OFET touch sensors were fabricated by forming the 10 μm thick LC layer (4-cyano-4{sup ′}-pentylbiphenyl - 5CB) on top of the 50 nm thick channel layer (poly(3-hexylthiophene) - P3HT) that is coated on the in-plane aligned drain/source/gate electrodes (indium-tin oxide - ITO). As an external physical stimulation to examine the tactile touch performance, a weak nitrogen flow (83.3 μl/s) was employed to stimulate the LC layer of the touch device. The LC-g-OFET device exhibited p-type transistor characteristics with a hole mobility of 1.5 cm{sup 2}/Vs, but no sensing current by the nitrogen flow touch was measured at sufficiently high drain (V{sub D}) and gate (V{sub G}) voltages. However, a clear sensing current signal was detected at lower voltages, which was quite sensitive to the combination of V{sub D} and V{sub G}. The best voltage combination was V{sub D} = −0.2 V and V{sub G} = −1 V for the highest ratio of signal currents to base currents (i.e., signal-to-noise ratio). The change in the LC alignment upon the nitrogen flow touch was assigned as the mechanism for the present LC-g-OFET touch sensors.

  12. Liquid crystal wavefront corrector with modal response based on spreading of the electric field in a dielectric material.

    Science.gov (United States)

    Loktev, Mikhail; Vdovin, Gleb; Klimov, Nikolai; Kotova, Svetlana

    2007-03-19

    A novel liquid crystal (LC) wavefront corrector with smooth modal influence functions is proposed and realized. The device consists of a thin layer of planar aligned nematic LC sandwiched between a glass plate with a conductive electrode and a plate made of ceramic material with a very high dielectric constant. Control electrodes are positioned on the back side of the ceramic plate, opposite to the LC. The modal character of the response is determined by spreading of the electric field in the ceramic plate. The device implemented is operating in a reflective (mirror) mode; however, similar principles can be used to build a transmissive device. Low cost and simplicity of control make it a good alternative to continuous face-sheet deformable mirrors.

  13. Dielectric and electro-optical properties of polymer-stabilized liquid crystal. II. Polymer PiBMA dispersed in MBBA

    Science.gov (United States)

    Tripathi, Pankaj Kumar; Pande, Mukti; Singh, Shri

    2016-09-01

    In continuation of our earlier work (Pande et al. in Appl Phys A 122:217-226, 2016), we report the results of dielectric and electro-optical properties of pure MBBA and PSLC (polymer PiBMA dispersed in MBBA) systems. The polymer networks domains formed are found to be anisotropic and are oriented in the direction of electric field for both the planar and homeotropic alignment cells. The dielectric anisotropy, optical anisotropy, response time, threshold voltage, splay elastic constant and rotational viscosity were observed for both the LC and PSLC systems with electric field. The liquid crystal properties are affected significantly with increasing concentration of polymer in pure LC material. It has been observed that the polymer networks interaction plays a major role in changing the properties of PSLC system. The effect of dielectric loss and dielectric permittivity on both pure LC and PSLC systems is also discussed.

  14. LC-REHAB

    DEFF Research Database (Denmark)

    Lynggaard, Vibeke; May, Ole; Beauchamp, Alison;

    2014-01-01

    that learning and coping incorporated in cardiac rehabilitation will improve adherence in cardiac rehabilitation and may decrease morbidity and mortality. By describing learning and coping strategies the study aims to provide knowledge that can contribute to an increased transparency in patient education...... of cardiac rehabilitation it is important to develop patient education methods which can enhance adherence to this effective program. The LC-REHAB study aims to compare the effect of a new patient education strategy in cardiac rehabilitation called 'learning and coping' to that of standard care. Further...... the intervention group with learning and coping strategies incorporated into standard care in cardiac rehabilitation or the control group who receive the usual cardiac rehabilitation program. Learning and coping consists of two individual clarifying interviews, participation of experienced patients as educators...

  15. Measurement of characteristics and phase modulation accuracy increase of LC SLM "HoloEye PLUTO VIS"

    Science.gov (United States)

    Bondareva, A. P.; Cheremkhin, P. A.; Evtikhiev, N. N.; Krasnov, V. V.; Starikov, R. S.; Starikov, S. N.

    2014-09-01

    Phase liquid crystal spatial light modulators (LC SLM) are actively integrated in various optical systems for dynamic diffractive optical elements imaging. To achieve the best performance, high stability and linearity of phase modulation is required. This article presents results of measurement of characteristics and phase modulation accuracy increase of state of the art LC SLM with HD resolution "HoloEye PLUTO VIS".

  16. Asymmetric electrooptic response in a nematic liquid crystal

    Energy Technology Data Exchange (ETDEWEB)

    Dascalu, Constanta [Politechnica University of Bucharest, Bucharest (Romania)

    2001-06-01

    An asymmetric electrooptic response in nematic liquid crystal (LC) has been obtained. The liquid crystal hybrid cell was made by using a standard configuration. One of the ITO (Indium Tin Oxide) electrodes was covered with a surfactant, which induces a homeotropic alignment. The second of the indium tin oxide electrodes was covered by a thin layer of photopolymer, which was previously mixed with an acid, which favours a process of release of protons. Such cations are responsible of electrochemical process in the LC leading to an asymmetric electrooptic response, which depend on the polarity of the applied electric field. This fact is due to an internal field, which change the effective voltage thresholds for the reorientation of the liquid crystal. During the anodic polarization, the optical switching is inhibited because the effective field decreases below the threshold value. On contrary for the opposite polarization the effective field is enough to determine a homeotropic alignment. [Spanish] Se ha obtenido una respuesta electro-optica asimetrica en cristales liquidos neumaticos. La celula hibrida de cristal liquido fue construida utilizando una configuracion estandar. Uno de los electrodos ITO fue cubierto con una pelicula delgada de material organico para inducir una alineacion homeotropa. El otro electrodo ITO fue cubierto con una pelicula delgada de fotopolimero anteriormente mezclada con un acido para favorecer la emision de protones. Estos cationes son responsables del proceso electroquimico en LC, conduciendo a una respuesta electro-optica asimetrica que depende de la polaridad del campo electrico aplicado. Este efecto es originado por un campo interno que cambia el umbral efectivo del voltaje para la reorientacion del cristal liquido. Durante la polarizacion anodica, la conmutacion optica se inhibe debido a que el campo efectivo disminuye abajo del valor del umbral. Por el contrario, para la polarizacion opuesta el campo efectivo es suficiente para

  17. GISAXS in the study of supramolecular and hybrid liquid crystals

    Energy Technology Data Exchange (ETDEWEB)

    Ungar, G; Liu, F; Zeng, X B [Department of Engineering Materials, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Glettner, B; Prehm, M; Kieffer, R; Tschierske, C [Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Str. 2, D-06120 Halle/Saale (Germany)

    2010-10-01

    The use of grazing incidence small and intermediate angle X-ray scattering in the study of structure and alignment of thermotropic liquid crystals is illustrated on selected examples. These include columnar LC phases of a star-shaped mesogen, several honeycomb phases of T-shaped and X-shaped bolaamphiphilic LCs, and gold nanoparticles coated with mesogenic ligands. Sharp Bragg reflections from systems with 2-d and 3-d periodicities are obtained through annealing. Due to nearly perfect surface alignment in most cases, indexing of complex diffraction patterns is facilitated. Honeycomb cells with deformed hexagonal cross-sections, as well as kagome lattice, are shown. The tilt of the reciprocal lattice is shown to help establish the correct structure in the case of the stretched hexagonal honeycombs and the rhombohedral arrays of ordered strings of gold nanoparticles.

  18. Photochemical manipulation of colloidal structures in liquid-crystal colloids

    Science.gov (United States)

    Yamamoto, T.; Tabe, Y.; Yokoyama, H.

    2007-05-01

    We investigated photochemical manipulation of physical properties and colloidal structures in liquid-crystal (LC) colloids containing azobenzene compounds. In a LC suspension where polymeric particles were dispersed in a host LC, we achieved photochemical control of light-scattering properties of the suspension. In a nematic phase, when the suspension was sandwiched with two glass plates, the film became opaque. This would be attributable to an appearance of both multidomain structures of LC alignment and mismatches of refractive indices between the materials. The opaque state turned into a transparent one when a nematic-to-isotropic phase transition was induced by the trans-to-cis photoisomerization of the azo-dye. This will result from a disappearance of both the multidomain structures and the refractive-index mismatches in the isotropic phase. The transparent film went back into the initial opaque film when the nematic phase was obtained by the cis-to-trans photoisomerization. In a LC emulsion in which glycerol or water droplets were dispersed in liquid crystals, we examined photochemical change of defect structures and inter-droplet distances by the photochemical manner. At the initial state, Saturn ring and hedgehog defects were formed around the droplets. For the glycerol droplets, we observed structural transformations between Saturn ring and boojums on irradiation with ultra-violet and visible light. For the water droplets, the inter-droplet distances varied by changing defect size on the irradiation. These phenomena would result from modulation of anchoring conditions of the droplets by the photoisomerization of the azo-dyes.

  19. A Bayesian based functional mixed-effects model for analysis of LC-MS data.

    Science.gov (United States)

    Befekadu, Getachew K; Tadesse, Mahlet G; Ressom, Habtom W

    2009-01-01

    A Bayesian multilevel functional mixed-effects model with group specific random-effects is presented for analysis of liquid chromatography-mass spectrometry (LC-MS) data. The proposed framework allows alignment of LC-MS spectra with respect to both retention time (RT) and mass-to-charge ratio (m/z). Affine transformations are incorporated within the model to account for any variability along the RT and m/z dimensions. Simultaneous posterior inference of all unknown parameters is accomplished via Markov chain Monte Carlo method using the Gibbs sampling algorithm. The proposed approach is computationally tractable and allows incorporating prior knowledge in the inference process. We demonstrate the applicability of our approach for alignment of LC-MS spectra based on total ion count profiles derived from two LC-MS datasets.

  20. Tuning quantum-dot organization in liquid crystals for robust photonic applications.

    Science.gov (United States)

    Rodarte, Andrea L; Nuno, Zachary S; Cao, Blessing H; Pandolfi, Ronald J; Quint, Makiko T; Ghosh, Sayantani; Hein, Jason E; Hirst, Linda S

    2014-05-19

    Mesogenic ligands have the potential to provide control over the dispersion and stabilization of nanoparticles in liquid crystal (LC) phases. The creation of such hybrid materials is an important goal for the creation of soft tunable photonic devices, such as the LC laser. Herein, we present a comparison of isotropic and mesogenic ligands attached to the surface of CdSe (core-only) and CdSe/ZnS (core/shell) quantum dots (QDs). The mesogenic ligand's flexible arm structure enhances ligand alignment, with the local LC director promoting QD dispersion in the isotropic and nematic phases. To characterize QD dispersion on different length scales, we apply fluorescence microscopy, X-ray scattering, and scanning confocal photoluminescent imaging. These combined techniques demonstrate that the LC-modified QDs do not aggregate into the dense clusters observed for dots with simple isotropic ligands when dispersed in liquid crystal, but loosely associate in a fluid-like droplet with an average interparticle spacing >10 nm. Embedding the QDs in a cholesteric cavity, we observe comparable coupling effects to those reported for more closely packed isotropic ligands.

  1. A novel twisted nematic alignment and its effects on the electro-optical dynamics of nanoscale liquid crystalline films

    Science.gov (United States)

    Rauzan, Brittany; Lee, Lay Min; Nuzzo, Ralph

    2015-03-01

    Vibrational spectroscopic studies of a surface induced, twisted alignment of the nematic liquid crystal, 4-n-pentyl-4'-cyanobiphenyl (5CB) and its temperature-dependent electro-optical (EO) dynamics were studied near the crystalline-nematic and nematic-isotropic transition temperatures, and at a median temperature in the nematic phase. A 50 nm thick film of 5CB was confined in nanocavities defined by the dimensions of a gold interdigitated electrode array patterned on a unidirectionally polished ZnSe substrate. The film was assembled between two polished substrates bearing extended nanometer-scaled grooves that are oriented orthogonally to one another. The results show that with this anchoring scheme, the molecular director of the LC film undergoes a ninety-degree twist. Step-scan time resolved spectroscopy (TRS) measurements were made to determine the rate constants for the temperature-dependent EO dynamics of both the electric field-induced orientation and thermal relaxation processes of the LC film. The work rationalizes the impacts of organizational anisotropy and illustrates how it can be exploited as a design principle to effectively influence the electric field-induced dynamics of LC systems.

  2. Vibrating wire alignment technique

    CERN Document Server

    Xiao-Long, Wang; lei, Wu; Chun-Hua, Li

    2013-01-01

    Vibrating wire alignment technique is a kind of method which through measuring the spatial distribution of magnetic field to do the alignment and it can achieve very high alignment accuracy. Vibrating wire alignment technique can be applied for magnet fiducialization and accelerator straight section components alignment, it is a necessary supplement for conventional alignment method. This article will systematically expound the international research achievements of vibrating wire alignment technique, including vibrating wire model analysis, system frequency calculation, wire sag calculation and the relation between wire amplitude and magnetic induction intensity. On the basis of model analysis this article will introduce the alignment method which based on magnetic field measurement and the alignment method which based on amplitude and phase measurement. Finally, some basic questions will be discussed and the solutions will be given.

  3. Designs of Plasmonic Metamasks for Photopatterning Molecular Orientations in Liquid Crystals

    Directory of Open Access Journals (Sweden)

    Yubing Guo

    2016-12-01

    Full Text Available Aligning liquid crystal (LC molecules into spatially non-uniform orientation patterns is central to the functionalities of many emerging LC devices. Recently, we developed a new projection photopatterning technique by using plasmonic metamasks (PMMs, and demonstrated high-resolution and high-throughput patterning of molecular orientations into arbitrary patterns. Here we present comparisons between two different types of metamask designs: one based on curvilinear nanoslits in metal films; the other based on rectangular nanoapertures in metal films. By using numerical simulations and experimental studies, we show that the PMMs based on curvilinear nanoslits exhibit advantages in their broadband and high optical transmission, while face challenges in mask designing for arbitrary molecular orientations. In contrast, the PMMs based on nanoapertures, though limited in optical transmission, present the great advantage of allowing for patterning arbitrary molecular orientation fields.

  4. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    G.Gomez.

    Since June of 2009, the muon alignment group has focused on providing new alignment constants and on finalizing the hardware alignment reconstruction. Alignment constants for DTs and CSCs were provided for CRAFT09 data reprocessing. For DT chambers, the track-based alignment was repeated using CRAFT09 cosmic ray muons and validated using segment extrapolation and split cosmic tools. One difference with respect to the previous alignment is that only five degrees of freedom were aligned, leaving the rotation around the local x-axis to be better determined by the hardware system. Similarly, DT chambers poorly aligned by tracks (due to limited statistics) were aligned by a combination of photogrammetry and hardware-based alignment. For the CSC chambers, the hardware system provided alignment in global z and rotations about local x. Entire muon endcap rings were further corrected in the transverse plane (global x and y) by the track-based alignment. Single chamber track-based alignment suffers from poor statistic...

  5. Influence of silane additive Y9669 on STN liquid crystal alignment agent‘s performance%硅烷添加剂 Y9669对 STN 液晶取向剂性能的影响

    Institute of Scientific and Technical Information of China (English)

    汪映寒; 周于蓝; 刘斌; 龚世铭

    2015-01-01

    When the STN liquid crystal alignment agent is filmed and thermoformed on the surface of glass substrates in industrial production,it is necessary to clean the substrates with solvents.In the process of cleaning,the film often peels off from its substrate.To tackle this problem,an additive is required to improve the adhesive performance of the agent without sacrificing its viscosity,outlook, pretilt angle and hardness.A silane additive N-[3-(trimethoxysilyl)propyl]aniline (Y9669)is intro-duced into the agent.Five solutions were prepared for the agent in mixture with the additive in differ-ent proportions.The viscosity,outlook,pretilt angle,hardness and etc.of the solutions were exam-ined.The STN liquid crystal alignment agent system reaches its best overall performance when the si-lane additive Y9669 is added 0.5% equal to the solid content of the agent.The silane additive Y9669 could improve the adhesive performance to the substrate with almost no impact on the other perfor-mances of the agent.%在工业生产中,STN 液晶取向剂在以薄膜形式涂覆在玻璃基板表面并进行热固化后,需要用溶剂对其进行洗涤。在洗涤中,薄膜从玻璃基板上脱落的现象时有发生。针对这种现象,需要一种添加剂,在不影响 STN 液晶取向剂的粘度、外观、预倾角、硬度等性质的同时,提高其粘接性能。在液晶取向剂中引入了 N-苯基-3-氨基丙基三甲氧基硅烷(Y9669)添加剂,将硅烷添加剂以不同添加比例与取向剂搅拌混合后,得到5份添加剂含量不同的溶液。表征并对比了含有不同含量添加剂的 STN 液晶取向剂的粘度、外观、预倾角、硬度、粘接性等性质。实验结果表明:对于 STN 液晶取向剂体系,硅烷添加剂 Y9669的最佳添加比例为取向剂固含量的0.5%,此时得到的取向剂综合性能更加优异。硅烷添加剂 Y9669基本能够达到在不影响取向剂其他性能的同时,提高其对基板粘接性能的要求。

  6. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    G. Gomez and J. Pivarski

    2011-01-01

    Alignment efforts in the first few months of 2011 have shifted away from providing alignment constants (now a well established procedure) and focussed on some critical remaining issues. The single most important task left was to understand the systematic differences observed between the track-based (TB) and hardware-based (HW) barrel alignments: a systematic difference in r-φ and in z, which grew as a function of z, and which amounted to ~4-5 mm differences going from one end of the barrel to the other. This difference is now understood to be caused by the tracker alignment. The systematic differences disappear when the track-based barrel alignment is performed using the new “twist-free” tracker alignment. This removes the largest remaining source of systematic uncertainty. Since the barrel alignment is based on hardware, it does not suffer from the tracker twist. However, untwisting the tracker causes endcap disks (which are aligned ...

  7. Modelling the Electro-Optic Properties of Liquid Crystals.

    Science.gov (United States)

    MacGregor, Alastair R.

    Available from UMI in association with The British Library. Requires signed TDF. Liquid crystals (LCs) have been recognised as a phase of matter intermediate between solid and liquid for about 100 years. During this time a large variety of mesophases have been discovered but it is only recently that their physics have begun to be understood. However if LCs are to continue to compete successfully in the displays market an improved understanding of their electro-optic properties must be gained. This thesis describes work carried out on two different types of LC: nematic and ferroelectric chiral smectic C (SmC^{*} ). In the former the molecules are orientationally ordered and randomly positioned while in the latter they are orientationally ordered and arranged in layers. The local mean molecular orientation is called the director and defines the uniaxial optic axis in both types of LC. In a nematic guest-host (NGH) LC an anisotropically absorbing dye is dissolved in the LC and the dye molecules align so that their maximum absorption axis is parallel to the director. When an electric field is applied to a cell containing NGHLC the molecules tend to rotate, because of their dielectric anisotropy, and alter the cell's transmittance. Previous attempts to model the change in optical transmittance with voltage have assumed that the LC and dye molecules are perfectly aligned with the director. In this work the disorder of the molecules about the director is taken into account and the overall agreement between theory and experiment is improved considerably. A method of calculating how the SmC^ {*} director configuration and layer orientation vary with voltage is presented. This method is tested by calculating the transmittance of a 7 mu m thick SmC^{* } LC cell for different azimuthal orientations of the cell between crossed polarisers. It is shown that the theoretical and measured orientations which give minimum transmittance are in good agreement. It is also shown that the

  8. LC-MS based Metabolomics

    DEFF Research Database (Denmark)

    Magdenoska, Olivera

    with only 12C or 13C carbons were very low or even not measurable and showed minimal or no interference to the spiked amount of nonlabeled standards and their stable isotope-labeled internal standards (SIL-IS). Finally the developed IP-RP LC-MS method was coupled to a quadrupole time of flight (QTOF) MS...

  9. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    G.Gomez

    2010-01-01

    The main developments in muon alignment since March 2010 have been the production, approval and deployment of alignment constants for the ICHEP data reprocessing. In the barrel, a new geometry, combining information from both hardware and track-based alignment systems, has been developed for the first time. The hardware alignment provides an initial DT geometry, which is then anchored as a rigid solid, using the link alignment system, to a reference frame common to the tracker. The “GlobalPositionRecords” for both the Tracker and Muon systems are being used for the first time, and the initial tracker-muon relative positioning, based on the link alignment, yields good results within the photogrammetry uncertainties of the Tracker and alignment ring positions. For the first time, the optical and track-based alignments show good agreement between them; the optical alignment being refined by the track-based alignment. The resulting geometry is the most complete to date, aligning all 250 DTs, ...

  10. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    Z. Szillasi and G. Gomez.

    2013-01-01

    When CMS is opened up, major components of the Link and Barrel Alignment systems will be removed. This operation, besides allowing for maintenance of the detector underneath, is needed for making interventions that will reinforce the alignment measurements and make the operation of the alignment system more reliable. For that purpose and also for their general maintenance and recalibration, the alignment components will be transferred to the Alignment Lab situated in the ISR area. For the track-based alignment, attention is focused on the determination of systematic uncertainties, which have become dominant, since now there is a large statistics of muon tracks. This will allow for an improved Monte Carlo misalignment scenario and updated alignment position errors, crucial for high-momentum muon analysis such as Z′ searches.

  11. 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 per...

  12. 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.

  13. Liquid Crystals and Photonic Bandgap Fiber Components

    DEFF Research Database (Denmark)

    Weirich, Johannes; Wei, Lei; Scolari, Lara

    Liquid Crystal(LC)filled Photonic Crystal Fibers(PCFs) represent a promising platform for the design and the fabrication of tunable all-in fiber devices. Tunability is achieved by varying the refractive index of the LC thermally, optically or electrically. In this contribution we present important...... parts of the LC theory as well as an application of a LC infiltrated PCF subject to an external electrostatic field. The fiber is placed between two electrodes and the voltage is increased step by step leading to the reorientation of the LC in the fiber capillaries. This mechanism can be used to produce...... a swichable polarizer, and an on chip LC photonic bandgap fiber polarimeter is presented, which admits strong attenuation of one polarization direction while the other one is nearly unaffected....

  14. Simple way for achieving passive all-optical switching of continuous waves lasers using pure nematic liquid crystal.

    Science.gov (United States)

    Sheng, C; Chen, Q; Norwood, R A; Wang, J; Thomas, J; Peyghambarian, N

    2011-10-20

    We have examined pure nematic liquid crystal (LC), 4'-pentyl-4-biphenylcarbonitrile (5-CB), with a 90° twisted alignment within a cell made of two cross-polarized absorptive plastic polarizers, and investigated the nonlinear transmission properties using cw (532 nm) lasers. We observed optically self-activated polarization switching with a factor of three lower switching power than a dye-doped LC cell with similar linear transmittance using glass substrates. We also studied the dynamics of the switching processes and observed millisecond switching time. These studies have demonstrated a simpler but more efficient way for fabricating broadband, low switching power, millisecond time scale switching, and optical limiting devices. © 2011 Optical Society of America

  15. Low-Absorption Liquid Crystals for Infrared Beam Steering

    Science.gov (United States)

    2015-09-30

    absorption coefficient and d is the LC layer thickness . Let us take a~!0/cm as an example. For a 10-|j,m- thick LC layer, ad=0.01 and the transmittance...remains 99%. However, if the LC layer thickness (or effective optical path length) increases, then the absorption will increase exponentially, as Eq. (1...weight-and-power, 2) increasing mean-time-between- failure, and 3) reducing system complexity. Beam steering based on liquid crystal ( LC ) optical phase

  16. Ontology alignment with OLA

    OpenAIRE

    Euzenat, Jérôme; Loup, David; Touzani, Mohamed; Valtchev, Petko

    2004-01-01

    euzenat2004d; International audience; Using ontologies is the standard way to achieve interoperability of heterogeneous systems within the Semantic web. However, as the ontologies underlying two systems are not necessarily compatible, they may in turn need to be aligned. Similarity-based approaches to alignment seems to be both powerful and flexible enough to match the expressive power of languages like OWL. We present an alignment tool that follows the similarity-based paradigm, called OLA. ...

  17. Phosphorylation of the mitochondrial autophagy receptor Nix enhances its interaction with LC3 proteins.

    Science.gov (United States)

    Rogov, Vladimir V; Suzuki, Hironori; Marinković, Mija; Lang, Verena; Kato, Ryuichi; Kawasaki, Masato; Buljubašić, Maja; Šprung, Matilda; Rogova, Natalia; Wakatsuki, Soichi; Hamacher-Brady, Anne; Dötsch, Volker; Dikic, Ivan; Brady, Nathan R; Novak, Ivana

    2017-04-25

    The mitophagy receptor Nix interacts with LC3/GABARAP proteins, targeting mitochondria into autophagosomes for degradation. Here we present evidence for phosphorylation-driven regulation of the Nix:LC3B interaction. Isothermal titration calorimetry and NMR indicate a ~100 fold enhanced affinity of the serine 34/35-phosphorylated Nix LC3-interacting region (LIR) to LC3B and formation of a very rigid complex compared to the non-phosphorylated sequence. Moreover, the crystal structure of LC3B in complex with the Nix LIR peptide containing glutamic acids as phosphomimetic residues and NMR experiments revealed that LIR phosphorylation stabilizes the Nix:LC3B complex via formation of two additional hydrogen bonds between phosphorylated serines of Nix LIR and Arg11, Lys49 and Lys51 in LC3B. Substitution of Lys51 to Ala in LC3B abrogates binding of a phosphomimetic Nix mutant. Functionally, serine 34/35 phosphorylation enhances autophagosome recruitment to mitochondria in HeLa cells. Together, this study provides cellular, biochemical and biophysical evidence that phosphorylation of the LIR domain of Nix enhances mitophagy receptor engagement.

  18. Tidal alignment of galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Blazek, Jonathan; Vlah, Zvonimir; Seljak, Uroš

    2015-08-01

    We develop an analytic model for galaxy intrinsic alignments (IA) based on the theory of tidal alignment. We calculate all relevant nonlinear corrections at one-loop order, including effects from nonlinear density evolution, galaxy biasing, and source density weighting. Contributions from density weighting are found to be particularly important and lead to bias dependence of the IA amplitude, even on large scales. This effect may be responsible for much of the luminosity dependence in IA observations. The increase in IA amplitude for more highly biased galaxies reflects their locations in regions with large tidal fields. We also consider the impact of smoothing the tidal field on halo scales. We compare the performance of this consistent nonlinear model in describing the observed alignment of luminous red galaxies with the linear model as well as the frequently used "nonlinear alignment model," finding a significant improvement on small and intermediate scales. We also show that the cross-correlation between density and IA (the "GI" term) can be effectively separated into source alignment and source clustering, and we accurately model the observed alignment down to the one-halo regime using the tidal field from the fully nonlinear halo-matter cross correlation. Inside the one-halo regime, the average alignment of galaxies with density tracers no longer follows the tidal alignment prediction, likely reflecting nonlinear processes that must be considered when modeling IA on these scales. Finally, we discuss tidal alignment in the context of cosmic shear measurements.

  19. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    G.Gomez

    2010-01-01

    Most of the work in muon alignment since December 2009 has focused on the geometry reconstruction from the optical systems and improvements in the internal alignment of the DT chambers. The barrel optical alignment system has progressively evolved from reconstruction of single active planes to super-planes (December 09) to a new, full barrel reconstruction. Initial validation studies comparing this full barrel alignment at 0T with photogrammetry provide promising results. In addition, the method has been applied to CRAFT09 data, and the resulting alignment at 3.8T yields residuals from tracks (extrapolated from the tracker) which look smooth, suggesting a good internal barrel alignment with a small overall offset with respect to the tracker. This is a significant improvement, which should allow the optical system to provide a start-up alignment for 2010. The end-cap optical alignment has made considerable progress in the analysis of transfer line data. The next set of alignment constants for CSCs will there...

  20. Electro-optically tunable diffraction grating with photoaligned liquid crystals

    Science.gov (United States)

    Węgłowski, Rafał; Kozanecka-Szmigiel, Anna; Piecek, Wiktor; Konieczkowska, Jolanta; Schab-Balcerzak, Ewa

    2017-10-01

    This work shows the possibility of fabricating one- and two-dimensional diffraction structures based on liquid crystals photoaligned with the layers of photosensitive azobenzene poly(ester imide). The gratings involve a micron-sized planar-twisted nematic alignment. The diffraction efficiency of these gratings is controlled by a uniform electric field applied across the cell. The electro-optical measurements showed short switching times (0.8 ms and 7 ms for τrise and τdecay respectively) and low driving electric fields (1 . 5 V / μm) of 1st order diffracted light. The LC grating is regarded as an amplitude grating in the low electric field region and a phase grating in the high electric field region. Moreover the diffraction efficiency is polarization-independent in the wide range of external electric fields.

  1. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    G. Gomez

    Since December, the muon alignment community has focused on analyzing the data recorded so far in order to produce new DT and CSC Alignment Records for the second reprocessing of CRAFT data. Two independent algorithms were developed which align the DT chambers using global tracks, thus providing, for the first time, a relative alignment of the barrel with respect to the tracker. These results are an important ingredient for the second CRAFT reprocessing and allow, for example, a more detailed study of any possible mis-modelling of the magnetic field in the muon spectrometer. Both algorithms are constructed in such a way that the resulting alignment constants are not affected, to first order, by any such mis-modelling. The CSC chambers have not yet been included in this global track-based alignment due to a lack of statistics, since only a few cosmics go through the tracker and the CSCs. A strategy exists to align the CSCs using the barrel as a reference until collision tracks become available. Aligning the ...

  2. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    Gervasio Gomez

    The main progress of the muon alignment group since March has been in the refinement of both the track-based alignment for the DTs and the hardware-based alignment for the CSCs. For DT track-based alignment, there has been significant improvement in the internal alignment of the superlayers inside the DTs. In particular, the distance between superlayers is now corrected, eliminating the residual dependence on track impact angles, and good agreement is found between survey and track-based corrections. The new internal geometry has been approved to be included in the forthcoming reprocessing of CRAFT samples. The alignment of DTs with respect to the tracker using global tracks has also improved significantly, since the algorithms use the latest B-field mapping, better run selection criteria, optimized momentum cuts, and an alignment is now obtained for all six degrees of freedom (three spatial coordinates and three rotations) of the aligned DTs. This work is ongoing and at a stage where we are trying to unders...

  3. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    G.Gomez

    2011-01-01

    The Muon Alignment work now focuses on producing a new track-based alignment with higher track statistics, making systematic studies between the results of the hardware and track-based alignment methods and aligning the barrel using standalone muon tracks. Currently, the muon track reconstruction software uses a hardware-based alignment in the barrel (DT) and a track-based alignment in the endcaps (CSC). An important task is to assess the muon momentum resolution that can be achieved using the current muon alignment, especially for highly energetic muons. For this purpose, cosmic ray muons are used, since the rate of high-energy muons from collisions is very low and the event statistics are still limited. Cosmics have the advantage of higher statistics in the pT region above 100 GeV/c, but they have the disadvantage of having a mostly vertical topology, resulting in a very few global endcap muons. Only the barrel alignment has therefore been tested so far. Cosmic muons traversing CMS from top to bottom are s...

  4. Physics of Grain Alignment

    CERN Document Server

    Lazarian, A

    2000-01-01

    Aligned grains provide one of the easiest ways to study magnetic fields in diffuse gas and molecular clouds. How reliable our conclusions about the inferred magnetic field depends critically on our understanding of the physics of grain alignment. Although grain alignment is a problem of half a century standing recent progress achieved in the field makes us believe that we are approaching the solution of this mystery. I review basic physical processes involved in grain alignment and show why mechanisms that were favored for decades do not look so promising right now. I also discuss why the radiative torque mechanism ignored for more than 20 years looks right now the most powerful means of grain alignment.

  5. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    G. Gomez

    2011-01-01

    A new set of muon alignment constants was approved in August. The relative position between muon chambers is essentially unchanged, indicating good detector stability. The main changes concern the global positioning of the barrel and of the endcap rings to match the new Tracker geometry. Detailed studies of the differences between track-based and optical alignment of DTs have proven to be a valuable tool for constraining Tracker alignment weak modes, and this information is now being used as part of the alignment procedure. In addition to the “split-cosmic” analysis used to investigate the muon momentum resolution at high momentum, a new procedure based on reconstructing the invariant mass of di-muons from boosted Zs is under development. Both procedures show an improvement in the momentum precision of Global Muons with respect to Tracker-only Muons. Recent developments in track-based alignment include a better treatment of the tails of residual distributions and accounting for correla...

  6. SPEAR3 Construction Alignment

    Energy Technology Data Exchange (ETDEWEB)

    LeCocq, Catherine; Banuelos, Cristobal; Fuss, Brian; Gaudreault, Francis; Gaydosh, Michael; Griffin, Levirt; Imfeld, Hans; McDougal, John; Perry, Michael; Rogers,; /SLAC

    2005-08-17

    An ambitious seven month shutdown of the existing SPEAR2 synchrotron radiation facility was successfully completed in March 2004 when the first synchrotron light was observed in the new SPEAR3 ring, SPEAR3 completely replaced SPEAR2 with new components aligned on a new highly-flat concrete floor. Devices such as magnets and vacuum chambers had to be fiducialized and later aligned on girder rafts that were then placed into the ring over pre-aligned support plates. Key to the success of aligning this new ring was to ensure that the new beam orbit matched the old SPEAR2 orbit so that existing experimental beamlines would not have to be reoriented. In this presentation a pictorial summary of the Alignment Engineering Group's surveying tasks for the construction of the SPEAR3 ring is provided. Details on the networking and analysis of various surveys throughout the project can be found in the accompanying paper.

  7. Memory effect in composites of liquid crystal and silica aerosil

    Energy Technology Data Exchange (ETDEWEB)

    Relaix, Sabrina; Leheny, Robert L.; Reven, Linda; Sutton, Mark (McGill); (JHU)

    2012-02-07

    Aerosil silica nanoparticles dispersed in a liquid crystal (LC) possess the interesting property of keeping memory of an electric- or magnetic-field-induced orientation. Two types of memory have been identified: thermally erasable memory arising from the pinning of defect lines versus a 'permanent' memory where the orientation persists even after thermal cycling the samples up to the isotropic phase. To address the source of the latter type of memory, solid-state nuclear magnetic resonance spectroscopy and conventional x-ray diffraction (XRD) were first combined to characterize the LC orientational order as a function of multiple in-field temperature cycles. Microbeam XRD was then performed on aligned gels of different concentrations to gain knowledge of the structural properties at the origin of the memory effect. No detectable anisotropy of the gel or significant breaking of silica strands with heating ruled out the formation of an anisotropic silica network as the source of the permanent memory as previously proposed. Instead, support for a role of the surface memory effect, well known for planar substrates, in stabilizing the permanent memory was deduced from 'training' of the composites, that is, optimizing the orientational order through the thermal in-field cycling. The ability to train the composites is inversely proportional to the strength of the random-field disorder. The portion of thermally erasable memory also decreases as the silica density increases. We propose that the permanent memory originates from the surface memory effect operating at points of intersection in the silica network. These areas, where the LC is strongly confined with conflicted surface interactions, are trained to achieve an optimized orientation and subsequently act as sites from which the LC orientational order regrows after zero-field thermal cycling up to the isotropic phase.

  8. 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.

  9. Pyroelectric Study on Dipolar Alignment in 0.69Pb(Mg1/3Nb2/3)O3-0.31PbTiO3 Single Crystals

    Institute of Scientific and Technical Information of China (English)

    ZHAO Liang; SHEN Ming-Rong; CAO Wen-Wu

    2012-01-01

    Pyroelectric measurements are conducted during zero-Geld heating in [001], [110] and [111] poled 0.69Pb(Mg1/3 Nb2/3)O3-0.31PbTiO3 single crystals. Compared to the room-temperature-poled samples, the crystals poled by using the Rield cooling method show broad but well recognizable pyroelectric current peaks near 190℃, which is much higher than the Curie point (126℃) of the crystal. We propose that this peak of the crystals poled by field-cooling above the Curie point is ascribed to the order-disorder transition of the dipoles in polar nano-regions formed at the Burns temperature.%Pyroelectric measurements are conducted during zero-field heating in [001],[110] and [111] poled 0.69Pb(Mg1/3Nb2/3)O3-0.31PbTiO3 single crystals.Compared to the room-temperature-poled samples,the crystals poled by using the field cooling method show broad but well recognizable pyroelectric current peaks near 190℃,which is much higher than the Curie point (126℃) of the crystal.We propose that this peak of the crystals poled by field-cooling above the Curie point is ascribed to the order-disorder transition of the dipoles in polar nano-regions formed at the Burns temperature.

  10. Galaxy alignments: An overview

    CERN Document Server

    Joachimi, Benjamin; Kitching, Thomas D; Leonard, Adrienne; Mandelbaum, Rachel; Schäfer, Björn Malte; Sifón, Cristóbal; Hoekstra, Henk; Kiessling, Alina; Kirk, Donnacha; Rassat, Anais

    2015-01-01

    The alignments between galaxies, their underlying matter structures, and the cosmic web constitute vital ingredients for a comprehensive understanding of gravity, the nature of matter, and structure formation in the Universe. We provide an overview on the state of the art in the study of these alignment processes and their observational signatures, aimed at a non-specialist audience. The development of the field over the past one hundred years is briefly reviewed. We also discuss the impact of galaxy alignments on measurements of weak gravitational lensing, and discuss avenues for making theoretical and observational progress over the coming decade.

  11. Discriminative Shape Alignment

    DEFF Research Database (Denmark)

    Loog, M.; de Bruijne, M.

    2009-01-01

    The alignment of shape data to a common mean before its subsequent processing is an ubiquitous step within the area shape analysis. Current approaches to shape analysis or, as more specifically considered in this work, shape classification perform the alignment in a fully unsupervised way......, not taking into account that eventually the shapes are to be assigned to two or more different classes. This work introduces a discriminative variation to well-known Procrustes alignment and demonstrates its benefit over this classical method in shape classification tasks. The focus is on two......-dimensional shapes from a two-class recognition problem....

  12. Compound liquid crystal microlens array with convergent and divergent functions.

    Science.gov (United States)

    Kang, Shengwu; Zhang, Xinyu

    2016-04-20

    Based on the common liquid crystal microlens, a new compound structure for a liquid crystal (LC) microlens array is proposed. The structure consists of two sub LC microlens arrays with properties of light divergence and convergence. The structure has two LC layers: one to form the positive sub lens, one for the negative. The patterned electrode and plane electrode are used in both sub microlens arrays. When two sub microlens arrays are electrically controlled separately, they can diverge or converge the incident light, respectively. As two sub microlens arrays are both applied on the voltage, the focal length of the compound LC microlens becomes larger than that of the LC microlens with a single LC layer. Another feature of a compound LC microlens array is that it can make the target contour become visible under intense light. The mechanisms are described in detail, and the experimental data are given.

  13. Effect of L-cysteine on optical, thermal and mechanical properties of ADP crystal for NLO application

    Science.gov (United States)

    Shaikh, R. N.; Shirsat, M. D.; Koinkar, P. M.; Hussaini, S. S.

    2015-06-01

    The ammonium dihydrogen phosphate (ADP) crystal doped with amino acid L-cysteine (LC) was grown by a slow evaporation technique. The grown crystal was transparent in the entire visible region, which is an essential requirement for a nonlinear crystal. The LC doping enhances the optical band gap of ADP (5.35 eV). The TG/DTA analysis of LC doped ADP crystal confirms the optimum thermal stability of grown crystal. The enhancement in the mechanical stability after LC doping was confirmed by Vicker's microhardness test. The LC doping showed significant impact on dielectric properties (dielectric constant and dielectric loss) of grown crystal. The third order nonlinear behavior of LC doped ADP crystal was investigated using a Z-scan technique at 632.8 nm and effective nonlinear optical parameters were evaluated.

  14. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    G.Gomez

    Since September, the muon alignment system shifted from a mode of hardware installation and commissioning to operation and data taking. All three optical subsystems (Barrel, Endcap and Link alignment) have recorded data before, during and after CRAFT, at different magnetic fields and during ramps of the magnet. This first data taking experience has several interesting goals: •    study detector deformations and movements under the influence of the huge magnetic forces; •    study the stability of detector structures and of the alignment system over long periods, •    study geometry reproducibility at equal fields (specially at 0T and 3.8T); •    reconstruct B=0T geometry and compare to nominal/survey geometries; •    reconstruct B=3.8T geometry and provide DT and CSC alignment records for CMSSW. However, the main goal is to recons...

  15. Activating photonic crystal membrane nanocavities by infiltrating with liquid crystals or luminescent colloidal nanocrystals

    NARCIS (Netherlands)

    Dündar, M.A.; Christova, C.; Silov, A.Y.; Karouta, F.; Nötzel, R.; Wienk, M.; Salemink, H.; Van der Heijden, R.W.

    2010-01-01

    Liquid crystal (LC, Merk 5 CB) is infiltrated into active, InAs quantum dots embedded, InGaAsP membrane type nanocavities to investigate the possible effect of the LC orientation on active cavity tuning. The tuning is demonstrated thermally and thermo-optically. The thermal tuning showed that the ca

  16. Activating photonic crystal membrane nanocavities by infiltrating with liquid crystals or luminescent colloidal nanocrystals

    NARCIS (Netherlands)

    Dündar, M.A.; Christova, C.; Silov, A.Y.; Karouta, F.; Nötzel, R.; Wienk, M.; Salemink, H.; Van der Heijden, R.

    2010-01-01

    Liquid crystal (LC, Merk 5 CB) is infiltrated into active, InAs quantum dots embedded, InGaAsP membrane type nanocavities to investigate the possible effect of the LC orientation on active cavity tuning. The tuning is demonstrated thermally and thermo-optically. The thermal tuning showed that the c

  17. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    S. Szillasi

    2013-01-01

    The CMS detector has been gradually opened and whenever a wheel became exposed the first operation was the removal of the MABs, the sensor structures of the Hardware Barrel Alignment System. By the last days of June all 36 MABs have arrived at the Alignment Lab at the ISR where, as part of the Alignment Upgrade Project, they are refurbished with new Survey target holders. Their electronic checkout is on the way and finally they will be recalibrated. During LS1 the alignment system will be upgraded in order to allow more precise reconstruction of the MB4 chambers in Sector 10 and Sector 4. This requires new sensor components, so called MiniMABs (pictured below), that have already been assembled and calibrated. Image 6: Calibrated MiniMABs are ready for installation For the track-based alignment, the systematic uncertainties of the algorithm are under scrutiny: this study will enable the production of an improved Monte Carlo misalignment scenario and to update alignment position errors eventually, crucial...

  18. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    G. Gomez

    2012-01-01

      A new muon alignment has been produced for 2012 A+B data reconstruction. It uses the latest Tracker alignment and single-muon data samples to align both DTs and CSCs. Physics validation has been performed and shows a modest improvement in stand-alone muon momentum resolution in the barrel, where the alignment is essentially unchanged from the previous version. The reference-target track-based algorithm using only collision muons is employed for the first time to align the CSCs, and a substantial improvement in resolution is observed in the endcap and overlap regions for stand-alone muons. This new alignment is undergoing the approval process and is expected to be deployed as part of a new global tag in the beginning of December. The pT dependence of the φ-bias in curvature observed in Monte Carlo was traced to a relative vertical misalignment between the Tracker and barrel muon systems. Moving the barrel as a whole to match the Tracker cures this pT dependence, leaving only the &phi...

  19. Incremental Alignment Manifold Learning

    Institute of Scientific and Technical Information of China (English)

    Zhi Han; De-Yu Meng; Zong-Sen Xu; Nan-Nan Gu

    2011-01-01

    A new manifold learning method, called incremental alignment method (IAM), is proposed for nonlinear dimensionality reduction of high dimensional data with intrinsic low dimensionality. The main idea is to incrementally align low-dimensional coordinates of input data patch-by-patch to iteratively generate the representation of the entire dataset. The method consists of two major steps, the incremental step and the alignment step. The incremental step incrementally searches neighborhood patch to be aligned in the next step, and the alignment step iteratively aligns the low-dimensional coordinates of the neighborhood patch searched to generate the embeddings of the entire dataset. Compared with the existing manifold learning methods, the proposed method dominates in several aspects: high efficiency, easy out-of-sample extension, well metric-preserving, and averting of the local minima issue. All these properties are supported by a series of experiments performed on the synthetic and real-life datasets. In addition, the computational complexity of the proposed method is analyzed, and its efficiency is theoretically argued and experimentally demonstrated.

  20. 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

  1. Liquid crystal device and method thereof

    Science.gov (United States)

    Shiyanovskii, Sergij V; Gu, Mingxia; Lavrentovich, Oleg D

    2012-10-23

    The invention provides a liquid crystal device and method thereof. Subsequent to applying a first electrical voltage on a liquid crystal to induce a reorientation of the liquid crystal, a second electrical voltage with proper polarity is applied on the liquid crystal to assist the relaxation of the reorientation that was induced by the first electrical voltage. The "switch-off" phase of the liquid crystal can therefore be accelerated or temporally shortened, and the device can exhibit better performance such as fast response to on/off signals. The invention can be widely used LCD, LC shutter, LC lens, spatial light modulator, telecommunication device, tunable filter, beam steering device, and electrically driven LC device, among others.

  2. LC Data QUEST: A Technical Architecture for Community Federated Clinical Data Sharing.

    Science.gov (United States)

    Stephens, Kari A; Lin, Ching-Ping; Baldwin, Laura-Mae; Echo-Hawk, Abigail; Keppel, Gina A; Buchwald, Dedra; Whitener, Ron J; Korngiebel, Diane M; Berg, Alfred O; Black, Robert A; Tarczy-Hornoch, Peter

    2012-01-01

    The University of Washington Institute of Translational Health Sciences is engaged in a project, LC Data QUEST, building data sharing capacity in primary care practices serving rural and tribal populations in the Washington, Wyoming, Alaska, Montana, Idaho region to build research infrastructure. We report on the iterative process of developing the technical architecture for semantically aligning electronic health data in primary care settings across our pilot sites and tools that will facilitate linkages between the research and practice communities. Our architecture emphasizes sustainable technical solutions for addressing data extraction, alignment, quality, and metadata management. The architecture provides immediate benefits to participating partners via a clinical decision support tool and data querying functionality to support local quality improvement efforts. The FInDiT tool catalogues type, quantity, and quality of the data that are available across the LC Data QUEST data sharing architecture. These tools facilitate the bi-directional process of translational research.

  3. Fabrication of micro- and nanometre-scale polymer structures in liquid crystal devices for next generation photonics applications

    Science.gov (United States)

    Tartan, Chloe C.; Salter, Patrick S.; Booth, Martin J.; Morris, Stephen M.; Elston, Steve J.

    2016-09-01

    Direct Laser Writing (DLW) by two-photon photopolymerization (TPP) enables the fabrication of micron-scale polymeric structures in soft matter systems. The technique has implications in a broad range of optics and photonics; in particular fast-switching liquid crystal (LC) modes for the development of next generation display technologies. In this paper, we report two different methodologies using our TPP-based fabrication technique. Two explicit examples are provided of voltage-dependent LC director profiles that are inherently unstable, but which appear to be promising candidates for fast-switching photonics applications. In the first instance, 1 μm-thick periodic walls of polymer network are written into a planar aligned (parallel rubbed) nematic pi-cell device containing a nematic LC-monomer mixture. The structures are fabricated when the device is electrically driven into a fast-switching nematic LC state and aberrations induced by the device substrates are corrected for by virtue of the adaptive optics elements included within the DLW setup. Optical polarizing microscopy images taken post-fabrication reveal that polymer walls oriented perpendicular to the rubbing direction promote the stability of the so-called optically compensated bend mode upon removal of the externally applied field. In the second case, polymer walls are written in a nematic LC-optically adhesive glue mixture. A polymer- LCs-polymer-slices or `POLICRYPS' template is formed by immersing the device in acetone post-fabrication to remove any remaining non-crosslinked material. Injecting the resultant series of polymer microchannels ( 1 μm-thick) with a short-pitch, chiral nematic LC mixture leads to the spontaneous alignment of a fast-switching chiral nematic mode, where the helical axis lies parallel to the glass substrates. Optimal contrast between the bright and dark states of the uniform lying helix alignment is achieved when the structures are spaced at the order of the device thickness

  4. Curriculum Alignment Research Suggests that Alignment Can Improve Student Achievement

    Science.gov (United States)

    Squires, David

    2012-01-01

    Curriculum alignment research has developed showing the relationship among three alignment categories: the taught curriculum, the tested curriculum and the written curriculum. Each pair (for example, the taught and the written curriculum) shows a positive impact for aligning those results. Following this, alignment results from the Third…

  5. Curriculum Alignment Research Suggests that Alignment Can Improve Student Achievement

    Science.gov (United States)

    Squires, David

    2012-01-01

    Curriculum alignment research has developed showing the relationship among three alignment categories: the taught curriculum, the tested curriculum and the written curriculum. Each pair (for example, the taught and the written curriculum) shows a positive impact for aligning those results. Following this, alignment results from the Third…

  6. Ferro-based derivatizing agents for LC/MS an LC/EC/MS

    NARCIS (Netherlands)

    Seiwert, Bettina

    2007-01-01

    Within this thesis, the development and application of ferrocene-based derivatizing agents for LC/MS and LC/EC/MS is presented. The advantages of derivatization by ferrocenes are the similtaneous introduction of a mass tag and an electroactive group, which make them ideally suited for LC/MS and esp

  7. Single Molecule Studies on Dynamics in Liquid Crystals

    Directory of Open Access Journals (Sweden)

    Daniela Täuber

    2013-09-01

    Full Text Available Single molecule (SM methods are able to resolve structure related dynamics of guest molecules in liquid crystals (LC. Highly diluted small dye molecules on the one hand explore structure formation and LC dynamics, on the other hand they report about a distortion caused by the guest molecules. The anisotropic structure of LC materials is used to retrieve specific conformation related properties of larger guest molecules like conjugated polymers. This in particular sheds light on organization mechanisms within biological cells, where large molecules are found in nematic LC surroundings. This review gives a short overview related to the application of highly sensitive SM detection schemes in LC.

  8. MaxAlign: maximizing usable data in an alignment

    DEFF Research Database (Denmark)

    Oliveira, Rodrigo Gouveia; Sackett, Peter Wad; Pedersen, Anders Gorm

    2007-01-01

    BACKGROUND: The presence of gaps in an alignment of nucleotide or protein sequences is often an inconvenience for bioinformatical studies. In phylogenetic and other analyses, for instance, gapped columns are often discarded entirely from the alignment. RESULTS: MaxAlign is a program that optimizes...... the alignment prior to such analyses. Specifically, it maximizes the number of nucleotide (or amino acid) symbols that are present in gap-free columns - the alignment area - by selecting the optimal subset of sequences to exclude from the alignment. MaxAlign can be used prior to phylogenetic and bioinformatical...... analyses as well as in other situations where this form of alignment improvement is useful. In this work we test MaxAlign's performance in these tasks and compare the accuracy of phylogenetic estimates including and excluding gapped columns from the analysis, with and without processing with MaxAlign...

  9. MWIR/LWIR filter based on Liquid-Crystal Fabry-Perot structure for tunable spectral imaging detection

    Science.gov (United States)

    Zhang, Huaidong; Muhammad, Afzal; Luo, Jun; Tong, Qing; Lei, Yu; Zhang, Xinyu; Sang, Hongshi; Xie, Changsheng

    2015-03-01

    An electrically tunable medium-wave infrared (MWIR)/long-wave infrared (LWIR) filter based on the key structure of Liquid-Crystal (LC) Fabry-Perot (FP), which works in the wavelength range from 2.5 μm to 12 μm, is designed and fabricated successfully in this paper. According to the optical interference principle of the FP cavity and electrically controlled birefringence of nematic LC molecules, the particular functions including spectral selection and spectral staring and spectral adjustment, can be realized by the developed MWIR/LWIR filter driven and controlled electrically. As to the LC-FP filter, both planar reflective mirrors are shaped by depositing a layer of aluminum (Al) film (∼60 nm) over one side of double-side polished Zinc Selenide (ZnSe) wafer (∼1 mm), and then polyimide (PI) layer with the thickness of ∼100 nm is coated directly on Al film. With typical sandwich architecture, the depth of the cavity with nematic LC molecules sealed in is ∼7.5 μm. To make sure the LC molecules parallel aligned and twist regularly under voltage driving signal applied on Al film, which also acts as electrode, the V-grooves are formed in PI layer with the depth of ∼90 nm and the width of ∼350 nm at average by strong rubbing. The typical transmission spectrum in MWIR&LWIR wavelength range and several spectral images in MWIR wavelength range based on the fabricated LC-FP filter, have been obtained through applying a voltage driving-signal with different root-means-square (RMS) value over the electrodes of LC-FP filter in the selected voltage range from 0VRMS to 19.8VRMS. The testing result demonstrates a prospect of realization smart spectral imaging and further integrating the LC-FP filter with infrared focal plane arrays (FPAs) to achieve the purpose infrared multispectral imaging. The developed MWIR&LWIR LC-FP filters show some obvious advantages such as wide working wavelength range, electrically tunable spectral selection, ultra-compact, low cost, being

  10. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    Gervasio Gomez

    2012-01-01

      The new alignment for the DT chambers has been successfully used in physics analysis starting with the 52X Global Tag. The remaining main areas of development over the next few months will be preparing a new track-based CSC alignment and producing realistic APEs (alignment position errors) and MC misalignment scenarios to match the latest muon alignment constants. Work on these items has been delayed from the intended timeline, mostly due to a large involvement of the muon alignment man-power in physics analyses over the first half of this year. As CMS keeps probing higher and higher energies, special attention must be paid to the reconstruction of very-high-energy muons. Recent muon POG reports from mid-June show a φ-dependence in curvature bias in Monte Carlo samples. This bias is observed already at the tracker level, where it is constant with muon pT, while it grows with pT as muon chamber information is added to the tracks. Similar studies show a much smaller effect in data, at le...

  11. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    G. Gomez

    2010-01-01

    For the last three months, the Muon Alignment group has focussed on providing a new, improved set of alignment constants for the end-of-year data reprocessing. These constants were delivered on time and approved by the CMS physics validation team on November 17. The new alignment incorporates several improvements over the previous one from March for nearly all sub-systems. Motivated by the loss of information from a hardware failure in May (an entire MAB was lost), the optical barrel alignment has moved from a modular, super-plane reconstruction, to a full, single loop calculation of the entire geometry for all DTs in stations 1, 2 and 3. This makes better use of the system redundancy, mitigating the effect of the information loss. Station 4 is factorised and added afterwards to make the system smaller (and therefore faster to run), and also because the MAB calibration at the MB4 zone is less precise. This new alignment procedure was tested at 0 T against photogrammetry resulting in precisions of the order...

  12. MUON DETECTORS: ALIGNMENT

    CERN Document Server

    M. Dallavalle

    2013-01-01

    A new Muon misalignment scenario for 2011 (7 TeV) Monte Carlo re-processing was re-leased. The scenario is based on running of standard track-based reference-target algorithm (exactly as in data) using single-muon simulated sample (with the transverse-momentum spectrum matching data). It used statistics similar to what was used for alignment with 2011 data, starting from an initially misaligned Muon geometry from uncertainties of hardware measurements and using the latest Tracker misalignment geometry. Validation of the scenario (with muons from Z decay and high-pT simulated muons) shows that it describes data well. The study of systematic uncertainties (dominant by now due to huge amount of data collected by CMS and used for muon alignment) is finalised. Realistic alignment position errors are being obtained from the estimated uncertainties and are expected to improve the muon reconstruction performance. Concerning the Hardware Alignment System, the upgrade of the Barrel Alignment is in progress. By now, d...

  13. Ergodic Secret Alignment

    CERN Document Server

    Bassily, Raef

    2010-01-01

    In this paper, we introduce two new achievable schemes for the fading multiple access wiretap channel (MAC-WT). In the model that we consider, we assume that perfect knowledge of the state of all channels is available at all the nodes in a causal fashion. Our schemes use this knowledge together with the time varying nature of the channel model to align the interference from different users at the eavesdropper perfectly in a one-dimensional space while creating a higher dimensionality space for the interfering signals at the legitimate receiver hence allowing for better chance of recovery. While we achieve this alignment through signal scaling at the transmitters in our first scheme (scaling based alignment (SBA)), we let nature provide this alignment through the ergodicity of the channel coefficients in the second scheme (ergodic secret alignment (ESA)). For each scheme, we obtain the resulting achievable secrecy rate region. We show that the secrecy rates achieved by both schemes scale with SNR as 1/2log(SNR...

  14. Electrically tunable infrared filter based on the liquid crystal Fabry-Perot structure for spectral imaging detection.

    Science.gov (United States)

    Zhang, Huaidong; Muhammmad, Afzal; Luo, Jun; Tong, Qing; Lei, Yu; Zhang, Xinyu; Sang, Hongshi; Xie, Changsheng

    2014-09-01

    An electrically tunable infrared (IR) filter based on the liquid crystal (LC) Fabry-Perot (FP) key structure, which works in the wavelength range from 5.5 to 12 μm, is designed and fabricated successfully. Both planar reflective mirrors with a very high reflectivity of ∼95%, which are shaped by depositing a layer of aluminum (Al) film over one side of a double-sided polished zinc selenide wafer, are coupled into a dual-mirror FP cavity. The LC materials are filled into the FP cavity with a thickness of ∼7.5  μm for constructing the LC-FP filter, which is a typical type of sandwich architecture. The top and bottom mirrors of the FP cavity are further coated by an alignment layer with a thickness of ∼100  nm over Al film. The formed alignment layer is rubbed strongly to shape relatively deep V-grooves to anchor LC molecules effectively. Common optical tests show some particular properties; for instance, the existing three transmission peaks in the measured wavelength range, the minimum full width at half-maximum being ∼120  nm, and the maximum adjustment extent of the imaging wavelength being ∼500  nm through applying the voltage driving signal with a root mean square (RMS) value ranging from 0 to ∼19.8  V. The experiment results are consistent with the simulation, according to our model setup. The spectral images obtained in the long-wavelength IR range, through the LC-FP device driven by the voltage signal with a different RMS value, demonstrates the prospect of the realization of smart spectral imaging and further integrating the LC-FP filter with IR focal plane arrays. The developed LC-FP filters show some advantages, such as electrically tunable imaging wavelength, very high structural and photoelectronic response stability, small size and low power consumption, and a very high filling factor of more than 95% compared with common MEMS-FP spectral imaging approaches.

  15. Ultrasound visualization using polymer dispersed liquid crystal sensors

    Science.gov (United States)

    Edwards, R. S.; Trushkevych, O.; Eriksson, T. J. R.; Ramadas, S. N.; Dixon, S.

    2017-02-01

    The acousto-optic effect in liquid crystals (LCs) has previously been exploited to build large area acoustic sensors for visualising ultrasound fields, opening up the field of acoustography. There is an opportunity to simplify this technique and open new application areas by employing polymer dispersed LC (PDLC) thin films instead of aligned LC layers. In PDLCs, the normally opaque film becomes transparent under the influence of an acoustic field (e.g. when surface acoustic waves are propagating in the material under the film). This is called acoustic clearing and is visible by eye. There is potential for producing ultrasonic sensors which can be `painted on' to a component, giving direct visualisation of the ultrasonic field without requiring scanning. We demonstrate the effect by using PDLC films to characterise a resonant mode of a flexural air-coupled transducer. Visualisation was quick, with a switching time of a few seconds. The effect shows promise for ultrasound sensing applications for transducer characterisation and NDE.

  16. FMIT alignment cart

    Energy Technology Data Exchange (ETDEWEB)

    Potter, R.C.; Dauelsberg, L.B.; Clark, D.C.; Grieggs, R.J.

    1981-01-01

    The Fusion Materials Irradiation Test (FMIT) Facility alignment cart must perform several functions. It must serve as a fixture to receive the drift-tube girder assembly when it is removed from the linac tank. It must transport the girder assembly from the linac vault to the area where alignment or disassembly is to take place. It must serve as a disassembly fixture to hold the girder while individual drift tubes are removed for repair. It must align the drift tube bores in a straight line parallel to the girder, using an optical system. These functions must be performed without violating any clearances found within the building. The bore tubes of the drift tubes will be irradiated, and shielding will be included in the system for easier maintenance.

  17. Light-induced deformation of photoresponsive liquid crystals on a water surface.

    Science.gov (United States)

    Okano, Kunihiko; Shinohara, Masato; Yamashita, Takashi

    2009-01-01

    Photodeformation: Azobenzene derivatives showing a room-temperature liquid crystal (LC) phase exhibit photoinduced deformation on a water surface. While a droplet of a LC sample floating on the surface expands upon UV irradiation, a LC sample containing a solvent is condensed towards the center of the illuminated regions (see figure).

  18. Getting Your Peaks in Line: A Review of Alignment Methods for NMR Spectral Data

    Directory of Open Access Journals (Sweden)

    Trung Nghia Vu

    2013-04-01

    Full Text Available One of the most significant challenges in the comparative analysis of Nuclear Magnetic Resonance (NMR metabolome profiles is the occurrence of shifts between peaks across different spectra, for example caused by fluctuations in pH, temperature, instrument factors and ion content. Proper alignment of spectral peaks is therefore often a crucial preprocessing step prior to downstream quantitative analysis. Various alignment methods have been developed specifically for this purpose. Other methods were originally developed to align other data types (GC, LC, SELDI-MS, etc., but can also be applied to NMR data. This review discusses the available methods, as well as related problems such as reference determination or the evaluation of alignment quality. We present a generic alignment framework that allows for comparison and classification of different alignment approaches according to their algorithmic principles, and we discuss their performance.

  19. Strategic Alignment of Business Intelligence

    OpenAIRE

    Cederberg, Niclas

    2010-01-01

    This thesis is about the concept of strategic alignment of business intelligence. It is based on a theoretical foundation that is used to define and explain business intelligence, data warehousing and strategic alignment. By combining a number of different methods for strategic alignment a framework for alignment of business intelligence is suggested. This framework addresses all different aspects of business intelligence identified as relevant for strategic alignment of business intelligence...

  20. PILOT optical alignment

    Science.gov (United States)

    Longval, Y.; Mot, B.; Ade, P.; André, Y.; Aumont, J.; Baustista, L.; Bernard, J.-Ph.; Bray, N.; de Bernardis, P.; Boulade, O.; Bousquet, F.; Bouzit, M.; Buttice, V.; Caillat, A.; Charra, M.; Chaigneau, M.; Crane, B.; Crussaire, J.-P.; Douchin, F.; Doumayrou, E.; Dubois, J.-P.; Engel, C.; Etcheto, P.; Gélot, P.; Griffin, M.; Foenard, G.; Grabarnik, S.; Hargrave, P..; Hughes, A.; Laureijs, R.; Lepennec, Y.; Leriche, B.; Maestre, S.; Maffei, B.; Martignac, J.; Marty, C.; Marty, W.; Masi, S.; Mirc, F.; Misawa, R.; Montel, J.; Montier, L.; Narbonne, J.; Nicot, J.-M.; Pajot, F.; Parot, G.; Pérot, E.; Pimentao, J.; Pisano, G.; Ponthieu, N.; Ristorcelli, I.; Rodriguez, L.; Roudil, G.; Salatino, M.; Savini, G.; Simonella, O.; Saccoccio, M.; Tapie, P.; Tauber, J.; Torre, J.-P.; Tucker, C.

    2016-07-01

    PILOT is a balloon-borne astronomy experiment designed to study the polarization of dust emission in the diffuse interstellar medium in our Galaxy at wavelengths 240 μm with an angular resolution about two arcminutes. Pilot optics is composed an off-axis Gregorian type telescope and a refractive re-imager system. All optical elements, except the primary mirror, are in a cryostat cooled to 3K. We combined the optical, 3D dimensional measurement methods and thermo-elastic modeling to perform the optical alignment. The talk describes the system analysis, the alignment procedure, and finally the performances obtained during the first flight in September 2015.

  1. Group Based Interference Alignment

    CERN Document Server

    Ma, Yanjun; Chen, Rui; Yao, Junliang

    2010-01-01

    in $K$-user single-input single-output (SISO) frequency selective fading interference channels, it is shown that the achievable multiplexing gain is almost surely $K/2$ by using interference alignment (IA). However when the signaling dimensions is limited, allocating all the resource to all the users simultaneously is not optimal. According to this problem, a group based interference alignment (GIA) scheme is proposed and a search algorithm is designed to get the group patterns and the resource allocation among them. Analysis results show that our proposed scheme achieves a higher multiplexing gain when the resource is limited.

  2. Orientation and Alignment Echoes

    CERN Document Server

    Karras, G; Billard, F; Lavorel, B; Hartmann, J -M; Faucher, O; Gershnabel, E; Prior, Y; Averbukh, I Sh

    2015-01-01

    We present what is probably the simplest classical system featuring the echo phenomenon - a collection of randomly oriented free rotors with dispersed rotational velocities. Following excitation by a pair of time-delayed impulsive kicks, the mean orientation/alignment of the ensemble exhibits multiple echoes and fractional echoes. We elucidate the mechanism of the echo formation by kick-induced filamentation of phase space, and provide the first experimental demonstration of classical alignment echoes in a thermal gas of CO_2 molecules excited by a pair of femtosecond laser pulses.

  3. Supercritical Fluid Chromatography- A Hybrid of GC and LC

    Directory of Open Access Journals (Sweden)

    Kaushal K Chandrul

    2010-03-01

    Full Text Available

    align: justify; line-height: normal;">High performance specifications and unique functionality of chromatographic techniques is a demand of pharmaceutical industry and research. This leads to the origin of Supercritical Fluid Chromatography (SFC. It is a rapidly expanding analytical technique. The main feature that differentiates SFC from other chromatographic techniques is the replacement of either the liquid or gas mobile phase with a supercritical fluid mobile phase. It is considered a hybrid of GC and LC technique. High diffusion coefficient and low viscosity of supercritical fluids is responsible for high speed analysis, high efficiency and high sensitivity. Low mobile-phase flow rate, density programming and compatability with GC and LC detectors make SFC a versatile chromatographic technique in analytical research and development. It has a unique characteristic of analyzing thermo labile or non-volatile substances. This review highlights the role of supercritical fluid chromatography in the separation of polymers, thermally labile pesticides, fatty acids, metal chelates and organometallic compounds, chiral and achiral molecules, identification and analysis of polar samples, explosives, drugs of abuse and application of SFC in forensic science (fingerprinting. 

  4. Simulation of beamline alignment operations

    Energy Technology Data Exchange (ETDEWEB)

    Annese, C; Miller, M G

    1999-02-02

    The CORBA-based Simulator was a Laboratory Directed Research and Development (LDRD) project that applied simulation techniques to explore critical questions about distributed control systems. The simulator project used a three-prong approach that studied object-oriented distribution tools, computer network modeling, and simulation of key control system scenarios. The National Ignition Facility's (NIF) optical alignment system was modeled to study control system operations. The alignment of NIF's 192 beamlines is a large complex operation involving more than 100 computer systems and 8000 mechanized devices. The alignment process is defined by a detailed set of procedures; however, many of the steps are deterministic. The alignment steps for a poorly aligned component are similar to that of a nearly aligned component; however, additional operations/iterations are required to complete the process. Thus, the same alignment operations will require variable amounts of time to perform depending on the current alignment condition as well as other factors. Simulation of the alignment process is necessary to understand beamline alignment time requirements and how shared resources such as the Output Sensor and Target Alignment Sensor effect alignment efficiency. The simulation has provided alignment time estimates and other results based on documented alignment procedures and alignment experience gained in the laboratory. Computer communication time, mechanical hardware actuation times, image processing algorithm execution times, etc. have been experimentally determined and incorporated into the model. Previous analysis of alignment operations utilized average implementation times for all alignment operations. Resource sharing becomes rather simple to model when only average values are used. The time required to actually implement the many individual alignment operations will be quite dynamic. The simulation model estimates the time to complete an operation using

  5. Aligning Responsible Business Practices

    DEFF Research Database (Denmark)

    Weller, Angeli E.

    2017-01-01

    This article offers an in-depth case study of a global high tech manufacturer that aligned its ethics and compliance, corporate social responsibility, and sustainability practices. Few large companies organize their responsible business practices this way, despite conceptual relevance and calls...... and managers interested in understanding how responsible business practices may be collectively organized....

  6. MUON DETECTORS: ALIGNMENT

    CERN Multimedia

    G. Gomez and Y. Pakhotin

    2012-01-01

      A new track-based alignment for the DT chambers is ready for deployment: an offline tag has already been produced which will become part of the 52X Global Tag. This alignment was validated within the muon alignment group both at low and high momentum using a W/Z skim sample. It shows an improved mass resolution for pairs of stand-alone muons, improved curvature resolution at high momentum, and improved DT segment extrapolation residuals. The validation workflow for high-momentum muons used to depend solely on the “split cosmics” method, looking at the curvature difference between muon tracks reconstructed in the upper or lower half of CMS. The validation has now been extended to include energetic muons decaying from heavily boosted Zs: the di-muon invariant mass for global and stand-alone muons is reconstructed, and the invariant mass resolution is compared for different alignments. The main areas of development over the next few months will be preparing a new track-based C...

  7. Aligning Theory with Practice

    Science.gov (United States)

    Kurz, Terri L.; Batarelo, Ivana

    2009-01-01

    This article describes a structure to help preservice teachers get invaluable field experience by aligning theory with practice supported by the integration of elementary school children into their university mathematics methodology course. This course structure allowed preservice teachers to learn about teaching mathematics in a nonthreatening…

  8. Alignment of concerns

    DEFF Research Database (Denmark)

    Andersen, Tariq Osman; Bansler, Jørgen P.; Kensing, Finn;

    2014-01-01

    The emergence of patient-centered eHealth systems introduces new challenges, where patients come to play an increasingly important role. Realizing the promises requires an in-depth understanding of not only the technology, but also the needs of both clinicians and patients. However, insights from...... as a design rationale for successful eHealth, termed 'alignment of concerns'....

  9. Aligning Mental Representations

    DEFF Research Database (Denmark)

    Kano Glückstad, Fumiko

    2013-01-01

    on the application of the BMG to publicly available datasets, the Leuven natural concept database [3] representing semantic structures of domain knowledge possessed by individual subjects [3]. Results indicate that the BMG is potentially a model applicable to simulating the alignment of domain knowledge from...

  10. Biased liquid crystal infiltrated photonic bandgap fiber

    DEFF Research Database (Denmark)

    Weirich, Johannes; Lægsgaard, Jesper; Scolari, Lara

    2009-01-01

    A simulation scheme for the transmission spectrum of a photonic crystal fiber infiltrated with a nematic liquid crystal and subject to an external bias is presented. The alignment of the biased liquid crystal is simulated using the finite element method to solve the relevant system of coupled...... partial differential equations. From the liquid crystal alignment the full tensorial dielectric permittivity in the capillaries is derived. The transmission spectrum for the photonic crystal fiber is obtained by solving the generalized eigenvalue problem deriving from Maxwell’s equations using a vector...... element based finite element method. We demonstrate results for a splay aligned liquid crystal infiltrated into the capillaries of a four-ring photonic crystal fiber and compare them to corresponding experiments....

  11. LC-MS systems for quantitative bioanalysis.

    Science.gov (United States)

    van Dongen, William D; Niessen, Wilfried M A

    2012-10-01

    LC-MS has become the method-of-choice in small-molecule drug bioanalysis (molecular mass Triple quadrupole MS is the established bioanalytical technique due to its unpreceded selectivity and sensitivity, but high-resolution accurate-mass MS is recently gaining ground due to its ability to provide simultaneous quantitative and qualitative analysis of drugs and their metabolites. This article discusses current trends in the field of bioanalytical LC-MS (until September 2012), and provides an overview of currently available commercial triple quadrupole MS and high-resolution LC-MS instruments as applied for the bioanalysis of small-molecule and biopharmaceutical drugs.

  12. LC Oscillator Driver for Safety Critical Applications

    CERN Document Server

    Horsky, Pavel

    2011-01-01

    A CMOS harmonic signal LC oscillator driver for automotive applications working in a harsh environment with high safety critical requirements is described. The driver can be used with a wide range of external components parameters (LC resonance network of a sensor). Quality factor of the external LC network can vary two decades. Amplitude regulation of the driver is digitally controlled and the DAC is constructed as exponential with piece-wise-linear (PWL) approximation. Low current consumption for high quality resonance networks is achieved. Realized oscillator is robust, used in safety critical application and has low EMC emissions.

  13. Ordering Quantum Dot Clusters via Nematic Liquid Crystal Defects

    Science.gov (United States)

    Rodarte, Andrea; Pandolfi, R.; Hirst, L. S.; Ghosh, S.

    2012-11-01

    Nematic liquid crystal (LC) materials can be used to create ordered clusters of CdSe/ZnS core/shell quantum dots (QDs) from a homogeneous isotropic dispersion. At the phase transition, the ordered domains of nematic LC expel the majority of dispersed QDs into the isotropic domains. The final LC phase produces a series of QD clusters that are situated at the defect points of the liquid crystal texture. Lower concentrations of QDs are organized in a network throughout the LC matrix that originates from the LC phase transition. Inside the QD clusters the inter-particle distance enables efficient energy transfer from high energy dots to lower energy dots. Because the QD clusters form at defect sites, the location of the clusters can be preselected by seeding the LC cell with defect nucleation points.

  14. Dispersions of Semiconductor Nanoparticles in Thermotropic Liquid Crystal: From Optical Modification to Assisted Self-Assembly

    Science.gov (United States)

    Rodarte, Andrea L.

    The interaction of semiconducting quantum dot nanoparticles (QDs) within thermotropic liquid crystalline (LC) materials are studied in this thesis. LC materials are ideal for bottom-up organization of nanoparticles as an active matrix that can be externally manipulated via electric or magnetic fields. In addition, the optical properties of QDs can be modified by the surrounding LC resulting in novel devices such as a quantum dot/liquid crystal laser. The first system studies the dispersion of spherical nanoparticles in the phase. The dispersion is investigated with the use of polarized optical microscopy, fluorescence microscopy and confocal scanning microscopy. Quantum dots well dispersed in the isotropic phase are expelled from ordered domains of LC at the phase transition. Under controlled conditions, the majority of QDs in the system can form ordered three dimensional assemblies that are situated at defect points in the liquid crystal. The internal order of the assemblies is probed utilizing Forster resonance energy transfer (FRET), combined with small angle X-ray scattering (SAXS). Furthermore, the location of these assemblies can be predetermined with the use of beads as defect nucleation points in the cell. The interaction of QDs in a cholesteric liquid crystal (CLC) is also investigated. The reflection band created by the periodic change of index of refraction in a planar aligned CLC acts as a 1-D photonic cavity when the CLC is doped with a low concentration of QDs. A Cano-wedge cell varies the pitch of the CLC leading to the formation of Grandjean steps. This spatially tunes the photonic stop band, changing the resonance condition and continuously altering both the emission wavelength and polarization state of the QD ensemble. Using high resolution spatially and spectrally resolved photoluminescence measurements, the emission is shown to be elliptically polarized and that the tilt of the ellipse, while dependent on the emission wavelength, additionally

  15. MetAlign 3.0: performance enhancement by efficient use of advances in computer hardware

    NARCIS (Netherlands)

    Lommen, A.; Kools, H.J.

    2012-01-01

    A new, multi-threaded version of the GC-MS and LC-MS data processing software, metAlign, has been developed which is able to utilize multiple cores on one PC. This new version was tested using three different multi-core PCs with different operating systems. The performance of noise reduction, baseli

  16. ABS: Sequence alignment by scanning

    KAUST Repository

    Bonny, Mohamed Talal

    2011-08-01

    Sequence alignment is an essential tool in almost any computational biology research. It processes large database sequences and considered to be high consumers of computation time. Heuristic algorithms are used to get approximate but fast results. We introduce fast alignment algorithm, called Alignment By Scanning (ABS), to provide an approximate alignment of two DNA sequences. We compare our algorithm with the well-known alignment algorithms, the FASTA (which is heuristic) and the \\'Needleman-Wunsch\\' (which is optimal). The proposed algorithm achieves up to 76% enhancement in alignment score when it is compared with the FASTA Algorithm. The evaluations are conducted using different lengths of DNA sequences. © 2011 IEEE.

  17. Fast global sequence alignment technique

    KAUST Repository

    Bonny, Mohamed Talal

    2011-11-01

    Bioinformatics database is growing exponentially in size. Processing these large amount of data may take hours of time even if super computers are used. One of the most important processing tool in Bioinformatics is sequence alignment. We introduce fast alignment algorithm, called \\'Alignment By Scanning\\' (ABS), to provide an approximate alignment of two DNA sequences. We compare our algorithm with the wellknown sequence alignment algorithms, the \\'GAP\\' (which is heuristic) and the \\'Needleman-Wunsch\\' (which is optimal). The proposed algorithm achieves up to 51% enhancement in alignment score when it is compared with the GAP Algorithm. The evaluations are conducted using different lengths of DNA sequences. © 2011 IEEE.

  18. Formatt: Correcting protein multiple structural alignments by incorporating sequence alignment

    Directory of Open Access Journals (Sweden)

    Daniels Noah M

    2012-10-01

    Full Text Available Abstract Background The quality of multiple protein structure alignments are usually computed and assessed based on geometric functions of the coordinates of the backbone atoms from the protein chains. These purely geometric methods do not utilize directly protein sequence similarity, and in fact, determining the proper way to incorporate sequence similarity measures into the construction and assessment of protein multiple structure alignments has proved surprisingly difficult. Results We present Formatt, a multiple structure alignment based on the Matt purely geometric multiple structure alignment program, that also takes into account sequence similarity when constructing alignments. We show that Formatt outperforms Matt and other popular structure alignment programs on the popular HOMSTRAD benchmark. For the SABMark twilight zone benchmark set that captures more remote homology, Formatt and Matt outperform other programs; depending on choice of embedded sequence aligner, Formatt produces either better sequence and structural alignments with a smaller core size than Matt, or similarly sized alignments with better sequence similarity, for a small cost in average RMSD. Conclusions Considering sequence information as well as purely geometric information seems to improve quality of multiple structure alignments, though defining what constitutes the best alignment when sequence and structural measures would suggest different alignments remains a difficult open question.

  19. Inflation by alignment

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, C.P. [PH -TH Division, CERN,CH-1211, Genève 23 (Switzerland); Department of Physics & Astronomy, McMaster University,1280 Main Street West, Hamilton ON (Canada); Perimeter Institute for Theoretical Physics,31 Caroline Street North, Waterloo ON (Canada); Roest, Diederik [Van Swinderen Institute for Particle Physics and Gravity, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands)

    2015-06-08

    Pseudo-Goldstone bosons (pGBs) can provide technically natural inflatons, as has been comparatively well-explored in the simplest axion examples. Although inflationary success requires trans-Planckian decay constants, f≳M{sub p}, several mechanisms have been proposed to obtain this, relying on (mis-)alignments between potential and kinetic energies in multiple-field models. We extend these mechanisms to a broader class of inflationary models, including in particular the exponential potentials that arise for pGB potentials based on noncompact groups (and so which might apply to moduli in an extra-dimensional setting). The resulting potentials provide natural large-field inflationary models and can predict a larger primordial tensor signal than is true for simpler single-field versions of these models. In so doing we provide a unified treatment of several alignment mechanisms, showing how each emerges as a limit of the more general setup.

  20. Aligning component upgrades

    Directory of Open Access Journals (Sweden)

    Roberto Di Cosmo

    2011-08-01

    Full Text Available Modern software systems, like GNU/Linux distributions or Eclipse-based development environment, are often deployed by selecting components out of large component repositories. Maintaining such software systems by performing component upgrades is a complex task, and the users need to have an expressive preferences language at their disposal to specify the kind of upgrades they are interested in. Recent research has shown that it is possible to develop solvers that handle preferences expressed as a combination of a few basic criteria used in the MISC competition, ranging from the number of new components to the freshness of the final configuration. In this work we introduce a set of new criteria that allow the users to specify their preferences for solutions with components aligned to the same upstream sources, provide an efficient encoding and report on the experimental results that prove that optimising these alignment criteria is a tractable problem in practice.

  1. Inflation by Alignment

    CERN Document Server

    Burgess, Cliff

    2015-01-01

    Pseudo-Goldstone bosons (pGBs) can provide technically natural inflatons, as has been comparatively well-explored in the simplest axion examples. Although inflationary success requires trans-Planckian decay constants, f > Mp, several mechanisms have been proposed to obtain this, relying on (mis-)alignments between potential and kinetic energies in multiple-field models. We extend these mechanisms to a broader class of inflationary models, including in particular the exponential potentials that arise for pGB potentials based on noncompact groups (and so which might apply to moduli in an extra-dimensional setting). The resulting potentials provide natural large-field inflationary models and can predict a larger primordial tensor signal than is true for simpler single-field versions of these models. In so doing we provide a unified treatment of several alignment mechanisms, showing how each emerges as a limit of the more general setup.

  2. Aligning component upgrades

    CERN Document Server

    Di Cosmo, Roberto; Michel, Claude; 10.4204/EPTCS.65.1

    2011-01-01

    Modern software systems, like GNU/Linux distributions or Eclipse-based development environment, are often deployed by selecting components out of large component repositories. Maintaining such software systems by performing component upgrades is a complex task, and the users need to have an expressive preferences language at their disposal to specify the kind of upgrades they are interested in. Recent research has shown that it is possible to develop solvers that handle preferences expressed as a combination of a few basic criteria used in the MISC competition, ranging from the number of new components to the freshness of the final configuration. In this work we introduce a set of new criteria that allow the users to specify their preferences for solutions with components aligned to the same upstream sources, provide an efficient encoding and report on the experimental results that prove that optimising these alignment criteria is a tractable problem in practice.

  3. Alignment of concerns

    DEFF Research Database (Denmark)

    Andersen, Tariq Osman; Bansler, Jørgen P.; Kensing, Finn

    E-health promises to enable and support active patient participation in chronic care. However, these fairly recent innovations are complicated matters and emphasize significant challenges, such as patients’ and clinicians’ different ways of conceptualizing disease and illness. Informed by insight...... from medical phenomenology and our own empirical work in telemonitoring and medical care of heart patients, we propose a design rationale for e-health systems conceptualized as the ‘alignment of concerns’....

  4. Orbit IMU alignment: Error analysis

    Science.gov (United States)

    Corson, R. W.

    1980-01-01

    A comprehensive accuracy analysis of orbit inertial measurement unit (IMU) alignments using the shuttle star trackers was completed and the results are presented. Monte Carlo techniques were used in a computer simulation of the IMU alignment hardware and software systems to: (1) determine the expected Space Transportation System 1 Flight (STS-1) manual mode IMU alignment accuracy; (2) investigate the accuracy of alignments in later shuttle flights when the automatic mode of star acquisition may be used; and (3) verify that an analytical model previously used for estimating the alignment error is a valid model. The analysis results do not differ significantly from expectations. The standard deviation in the IMU alignment error for STS-1 alignments was determined to the 68 arc seconds per axis. This corresponds to a 99.7% probability that the magnitude of the total alignment error is less than 258 arc seconds.

  5. Nuclear reactor alignment plate configuration

    Energy Technology Data Exchange (ETDEWEB)

    Altman, David A; Forsyth, David R; Smith, Richard E; Singleton, Norman R

    2014-01-28

    An alignment plate that is attached to a core barrel of a pressurized water reactor and fits within slots within a top plate of a lower core shroud and upper core plate to maintain lateral alignment of the reactor internals. The alignment plate is connected to the core barrel through two vertically-spaced dowel pins that extend from the outside surface of the core barrel through a reinforcement pad and into corresponding holes in the alignment plate. Additionally, threaded fasteners are inserted around the perimeter of the reinforcement pad and into the alignment plate to further secure the alignment plate to the core barrel. A fillet weld also is deposited around the perimeter of the reinforcement pad. To accomodate thermal growth between the alignment plate and the core barrel, a gap is left above, below and at both sides of one of the dowel pins in the alignment plate holes through with the dowel pins pass.

  6. Seeking the perfect alignment

    CERN Multimedia

    2002-01-01

    The first full-scale tests of the ATLAS Muon Spectrometer are about to begin in Prévessin. The set-up includes several layers of Monitored Drift Tubes Chambers (MDTs) and will allow tests of the performance of the detectors and of their highly accurate alignment system.   Monitored Drift Chambers in Building 887 in Prévessin, where they are just about to be tested. Muon chambers are keeping the ATLAS Muon Spectrometer team quite busy this summer. Now that most people go on holiday, the beam and alignment tests for these chambers are just starting. These chambers will measure with high accuracy the momentum of high-energy muons, and this implies very demanding requirements for their alignment. The MDT chambers consist of drift tubes, which are gas-filled metal tubes, 3 cm in diameter, with wires running down their axes. With high voltage between the wire and the tube wall, the ionisation due to traversing muons is detected as electrical pulses. With careful timing of the pulses, the position of the muon t...

  7. RECAT - Redundant Channel Alignment Technique

    Science.gov (United States)

    2016-06-07

    distribution unlimited 13. SUPPLEMENTARY NOTES NUWC2015 14. ABSTRACT A problem in the analog-to- digital , (A/D), conversion of broadband tape recorded...Alignment Technique, is used to align data taken on one pass with data from any other pass. The accuracy of this alignment is a function of the digital ...Redundant Channel Alignment Technique; analog-to- digital ; A/D; Broadband Bearing Time Processing 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  8. Reflection spectra of distorted cholesteric liquid crystal structures in cells with interdigitated electrodes.

    Science.gov (United States)

    Rumi, Mariacristina; White, Timothy J; Bunning, Timothy J

    2014-06-30

    We studied the appearance of second- and third-order Bragg reflections in cholesteric liquid crystals (CLCs) in cells where the electric field was perpendicular to the helical axis. Second-order reflections with reflectance values as large as 80% of the first-order one were observed in the gap regions of alignment cells with interdigitated electrodes for CLC mixtures with pitches in the range 0.5-1.0 μm upon application of a field. The characterization was enabled by local probing of the CLC using a microspectrophotometer. LC cells that are transparent in the visible spectrum in the off-state and become colored upon application of a field due the second- or third-order reflection band appearance were demonstrated. The spectral position of the higher-order Bragg reflections can also be tuned by adjusting the magnitude of the electric field.

  9. Silicon on insulator self-aligned transistors

    Science.gov (United States)

    McCarthy, Anthony M.

    2003-11-18

    A method for fabricating thin-film single-crystal silicon-on-insulator (SOI) self-aligned transistors. Standard processing of silicon substrates is used to fabricate the transistors. Physical spaces, between the source and gate, and the drain and gate, introduced by etching the polysilicon gate material, are used to provide connecting implants (bridges) which allow the transistor to perform normally. After completion of the silicon substrate processing, the silicon wafer is bonded to an insulator (glass) substrate, and the silicon substrate is removed leaving the transistors on the insulator (glass) substrate. Transistors fabricated by this method may be utilized, for example, in flat panel displays, etc.

  10. Method for alignment of microwires

    Energy Technology Data Exchange (ETDEWEB)

    Beardslee, Joseph A.; Lewis, Nathan S.; Sadtler, Bryce

    2017-01-24

    A method of aligning microwires includes modifying the microwires so they are more responsive to a magnetic field. The method also includes using a magnetic field so as to magnetically align the microwires. The method can further include capturing the microwires in a solid support structure that retains the longitudinal alignment of the microwires when the magnetic field is not applied to the microwires.

  11. Field induced heliconical structure of cholesteric liquid crystal

    Science.gov (United States)

    Lavrentovich, Oleg D.; Shiyanovsii, Sergij V.; Xiang, Jie; Kim, Young-Ki

    2017-06-27

    A diffraction grating comprises a liquid crystal (LC) cell configured to apply an electric field through a cholesteric LC material that induces the cholesteric LC material into a heliconical state with an oblique helicoid director. The applied electric field produces diffracted light from the cholesteric LC material within the visible, infrared or ultraviolet. The axis of the heliconical state is in the plane of the liquid crystal cell or perpendicular to the plane, depending on the application. A color tuning device operates with a similar heliconical state liquid crystal material but with the heliconical director axis oriented perpendicular to the plane of the cell. A power generator varies the strength of the applied electric field to adjust the wavelength of light reflected from the cholesteric liquid crystal material within the visible, infrared or ultraviolet.

  12. Theoretical analysis of a biased photonic crystal fiber infiltrated with a negative dielectric anisotropy liquid crystal

    DEFF Research Database (Denmark)

    Weirich, Johannes; Wei, Lei; Lægsgaard, Jesper;

    2009-01-01

    We simulate the PBG mode of a biased Photonic Crystal Fiber (PCF) infiltrated with a Liquid Crystal (LC) with negative dielectric anisotropy. We analyse the voltage induced change of the transmission spectrum, dispersion and losses and compare them to the experimental values....

  13. Processing methods for differential analysis of LC/MS profile data

    Directory of Open Access Journals (Sweden)

    Orešič Matej

    2005-07-01

    Full Text Available Abstract Background Liquid chromatography coupled to mass spectrometry (LC/MS has been widely used in proteomics and metabolomics research. In this context, the technology has been increasingly used for differential profiling, i.e. broad screening of biomolecular components across multiple samples in order to elucidate the observed phenotypes and discover biomarkers. One of the major challenges in this domain remains development of better solutions for processing of LC/MS data. Results We present a software package MZmine that enables differential LC/MS analysis of metabolomics data. This software is a toolbox containing methods for all data processing stages preceding differential analysis: spectral filtering, peak detection, alignment and normalization. Specifically, we developed and implemented a new recursive peak search algorithm and a secondary peak picking method for improving already aligned results, as well as a normalization tool that uses multiple internal standards. Visualization tools enable comparative viewing of data across multiple samples. Peak lists can be exported into other data analysis programs. The toolbox has already been utilized in a wide range of applications. We demonstrate its utility on an example of metabolic profiling of Catharanthus roseus cell cultures. Conclusion The software is freely available under the GNU General Public License and it can be obtained from the project web page at: http://mzmine.sourceforge.net/.

  14. Properties of polyimide liquid crystal alignment layer with different backbone structure%聚酰亚胺主链结构对液晶取向膜性能的影响

    Institute of Scientific and Technical Information of China (English)

    刘露露; 刘明; 龚世铭; 汪映寒

    2015-01-01

    A series polyimides (PIs)were prepared by one-step method.These PIs were comprised of a functional diamine N,N-bis (4-aminophenyl )-4-(dodecylo-xy-biphenyl )-4′-amino-phenylether (C1 2 -BAAPE),one of two commercially available diamines 2,2′-Bis(trifluoromethy-l)-4,4′-diaminobiphe-nyl (TFDB),4,4′-Oxydianiline (ODA)and one of two dianhydride 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA)and 4,4′-Oxydiphthalic anhydride (ODPA)in order to get different backbone structures.The structures and thermo properties of these PIs were characterized by NMR, FT-IR,DSC and TGA.Pretilt angles and alignment abilities were carried out by pretilt angle tester and polarization microscope.Solubility of PIs was tested by dissolving PIs in various organic solvents. DSC and TGA curves showed that PI-2 had higher glass transition temperature (T g )and decomposi-tion temperature (T d )than PI-1 and PI-3.Three PI films presented vertical alignment before mechan-ical rubbing and only PI-2 maintained it after rubbing process.Conformations of these PIs were simu-lated by Material Studio (MS).The vertical conformation existed in PI-2 ’s backbones improved rubbing resistance and showed vertical alignment ability after rubbing.%采用一步法,以 N,N-二(4-氨基苯基)-4-(十二烷氧基联苯基)-4’-氨基苯醚(C12-BAAPE)为控制预倾角的功能性二胺,2,2’-双三氟甲基-4,4’-联苯二胺(TFDB)或4,4’-二氨基二苯醚(ODA)为辅助二胺,分别与2,2’-双(3,4-二羧苯基)六氟丙烷四羧酸二酐(6FDA)和4,4’-联苯醚二酐(ODPA)聚合,得到三种主链结构不同的聚酰亚胺(PI-1、PI-2和PI-3)。利用 NMR、FT-IR、DSC、TGA、偏光显微镜和预倾角测试仪对聚合物的结构、热性能以及制备的液晶盒的取向性进行了表征,同时测试了3种 PI 的溶解性能。结果表明,PI-2液晶取向膜的耐摩擦性能明显优于 PI-1和 PI-3,且具有更高的玻璃化转变温度(T g )和分解温度(T d ),更好

  15. Carbon Nanoparticles in Nematic Liquid Crystals

    Institute of Scientific and Technical Information of China (English)

    S.Eren San; Mustafa Okutan; O(g)uz K(o)ysal; Yusuf Yer-li

    2008-01-01

    Fullerene G60,C70,single-walled and multi-walled carbon nanotubes and graphene sheets are doped to nematic liquid crystal(LC)host in the same percentage.Planar samples of these mixtures are prepared and our measurements constitute an optimization basis for possible applications.Fullerene balls are found to be the best compatible material for optical aims and reorientation of LC molecules,while the carbon nanotubes experience some reorientation possibility in LC media and graphene layers are good barriers to preserve reorientation.

  16. {beta}-ray Angular Distribution from Purely Nuclear Spin Aligned {sup 20}Na

    Energy Technology Data Exchange (ETDEWEB)

    Minamisono, K., E-mail: minamiso@nscl.msu.edu [NSCL/MSU (United States); Matsuta, K.; Minamisono, T. [Osaka University, Department of Physics (Japan); Levy, C. D. P. [TRIUMF (Canada); Nagatomo, T.; Ogura, M. [Osaka University, Department of Physics (Japan); Sumikama, T. [RIKEN (Japan); Behr, J. A.; Jackson, K. P. [TRIUMF (Canada); Fujiwara, H.; Mihara, M.; Fukuda, M. [Osaka University, Department of Physics (Japan)

    2004-12-15

    The alignment correlation term in the {beta}-decay angular distribution from purely nuclear spin aligned {sup 20}Na has been measured for the first time. The final objective is to test the G parity symmetry, one of the fundamental symmetry in the weak nucleon current. For artificial creation of the alignment, the knowledge of the hyperfine interaction of {sup 20}Na implanted in a single-crystal ZnO was utilized.

  17. {beta}-Ray angular distribution from purely nuclear spin aligned {sup 20}F

    Energy Technology Data Exchange (ETDEWEB)

    Nagatomo, T., E-mail: nagatomo@riken.jp [RIKEN Nishina Center (Japan); Matsuta, K. [Osaka University (Japan); Minamisono, K. [NSCL/MSU (United States); Sumikama, T. [Tokyo University of Science (Japan); Mihara, M. [Osaka University (Japan); Ozawa, A.; Tagishi, Y. [University of Tsukuba (Japan); Ogura, M.; Matsumiya, R.; Fukuda, M. [Osaka University (Japan); Yamaguchi, M.; Yasuno, T.; Ohta, H.; Hashizume, Y. [University of Tsukuba (Japan); Fujiwara, H. [Osaka University (Japan); Chiba, A. [University of Tsukuba (Japan); Minamisono, T. [Fukui University of Technology (Japan)

    2007-11-15

    The alignment correlation term in the {beta}-ray angular distribution from purely nuclear spin aligned {sup 20}F has been measured to test the G-parity conservation law which is one of the fundamental symmetries in the weak nucleon current. We utilized the hyperfine interaction of {sup 20}F in an MgF{sub 2} single crystal and successfully created the pure alignment from the polarization by means of the spin manipulation technique based on the {beta}-NMR method.

  18. Alignment of suprathermally rotating grains

    Science.gov (United States)

    Lazarian, A.

    1995-12-01

    It is shown that mechanical alignment can be efficient for suprathermally rotating grains, provided that they drift with supersonic velocities. Such a drift should be widely spread due to both Alfvenic waves and ambipolar diffusion. Moreover, if suprathermal rotation is caused by grain interaction with a radiative flux, it is shown that mechanical alignment may be present even in the absence of supersonic drift. This means that the range of applicability of mechanical alignment is wider than generally accepted and that it can rival the paramagnetic one. We also study the latter mechanism and re-examine the interplay between poisoning of active sites and desorption of molecules blocking the access to the active sites of H_2 formation, in order to explain the observed poor alignment of small grains and good alignment of large grains. To obtain a more comprehensive picture of alignment, we briefly discuss the alignment by radiation fluxes and by grain magnetic moments.

  19. Semiautomated improvement of RNA alignments

    DEFF Research Database (Denmark)

    Andersen, Ebbe Sloth; Lind-Thomsen, Allan; Knudsen, Bjarne

    2007-01-01

    We have developed a semiautomated RNA sequence editor (SARSE) that integrates tools for analyzing RNA alignments. The editor highlights different properties of the alignment by color, and its integrated analysis tools prevent the introduction of errors when doing alignment editing. SARSE readily...... connects to external tools to provide a flexible semiautomatic editing environment. A new method, Pcluster, is introduced for dividing the sequences of an RNA alignment into subgroups with secondary structure differences. Pcluster was used to evaluate 574 seed alignments obtained from the Rfam database...... and we identified 71 alignments with significant prediction of inconsistent base pairs and 102 alignments with significant prediction of novel base pairs. Four RNA families were used to illustrate how SARSE can be used to manually or automatically correct the inconsistent base pairs detected by Pcluster...

  20. CELT optics Alignment Procedure

    Science.gov (United States)

    Mast, Terry S.; Nelson, Jerry E.; Chanan, Gary A.; Noethe, Lothar

    2003-01-01

    The California Extremely Large Telescope (CELT) is a project to build a 30-meter diameter telescope for research in astronomy at visible and infrared wavelengths. The current optical design calls for a primary, secondary, and tertiary mirror with Ritchey-Chretién foci at two Nasmyth platforms. The primary mirror is a mosaic of 1080 actively-stabilized hexagonal segments. This paper summarizes a CELT report that describes a step-by-step procedure for aligning the many degrees of freedom of the CELT optics.

  1. ATLAS Inner Detector Alignment

    CERN Document Server

    Bocci, A

    2008-01-01

    The ATLAS experiment is a multi-purpose particle detector that will study high-energy particle collisions produced by the Large Hadron Collider at CERN. In order to achieve its physics goals, the ATLAS tracking requires that the positions of the silicon detector elements have to be known to a precision better than 10 μm. Several track-based alignment algorithms have been developed for the Inner Detector. An extensive validation has been performed with simulated events and real data coming from the ATLAS. Results from such validation are reported in this paper.

  2. TSGC and JSC Alignment

    Science.gov (United States)

    Sanchez, Humberto

    2013-01-01

    NASA and the SGCs are, by design, intended to work closely together and have synergistic Vision, Mission, and Goals. The TSGC affiliates and JSC have been working together, but not always in a concise, coordinated, nor strategic manner. Today we have a couple of simple ideas to present about how TSGC and JSC have started to work together in a more concise, coordinated, and strategic manner, and how JSC and non-TSG Jurisdiction members have started to collaborate: Idea I: TSGC and JSC Technical Alignment Idea II: Concept of Clusters.

  3. Comparison of Two Forced Alignment Systems for Aligning Bribri Speech

    Directory of Open Access Journals (Sweden)

    Rolando Coto-Solano

    2017-04-01

    Full Text Available Forced alignment provides drastic savings in time when aligning speech recordings and is particularly useful for the study of Indigenous languages, which are severely under-resourced in corpora and models. Here we compare two forced alignment systems, FAVE-align and EasyAlign, to determine which one provides more precision when processing running speech in the Chibchan language Bribri. We aligned a segment of a story narrated in Bribri and compared the errors in finding the center of the words and the edges of phonemes when compared with the manual correction. FAVE-align showed better performance: It has an error of 7% compared to 24% with EasyAlign when finding the center of words, and errors of 22~24 ms when finding the edges of phonemes, compared to errors of 86~130 ms with EasyAlign. In addition to this, EasyAlign failed to detect 7% of phonemes, while also inserting 58 spurious phones into the transcription. Future research includes verifying these results for other genres and other Chibchan languages. Finally, these results provide additional evidence for the applicability of natural language processing methods to Chibchan languages and point to future work such as the construction of corpora and the training of automated speech recognition systems.

  4. Aligned-Braided Nanofibrillar Scaffold with Endothelial Cells Enhances Arteriogenesis.

    Science.gov (United States)

    Nakayama, Karina H; Hong, Guosong; Lee, Jerry C; Patel, Jay; Edwards, Bryan; Zaitseva, Tatiana S; Paukshto, Michael V; Dai, Hongjie; Cooke, John P; Woo, Y Joseph; Huang, Ngan F

    2015-07-28

    The objective of this study was to enhance the angiogenic capacity of endothelial cells (ECs) using nanoscale signaling cues from aligned nanofibrillar scaffolds in the setting of tissue ischemia. Thread-like nanofibrillar scaffolds with porous structure were fabricated from aligned-braided membranes generated under shear from liquid crystal collagen solution. Human ECs showed greater outgrowth from aligned scaffolds than from nonpatterned scaffolds. Integrin α1 was in part responsible for the enhanced cellular outgrowth on aligned nanofibrillar scaffolds, as the effect was abrogated by integrin α1 inhibition. To test the efficacy of EC-seeded aligned nanofibrillar scaffolds in improving neovascularization in vivo, the ischemic limbs of mice were treated with EC-seeded aligned nanofibrillar scaffold; EC-seeded nonpatterned scaffold; ECs in saline; aligned nanofibrillar scaffold alone; or no treatment. After 14 days, laser Doppler blood spectroscopy demonstrated significant improvement in blood perfusion recovery when treated with EC-seeded aligned nanofibrillar scaffolds, in comparison to ECs in saline or no treatment. In ischemic hindlimbs treated with scaffolds seeded with human ECs derived from induced pluripotent stem cells (iPSC-ECs), single-walled carbon nanotube (SWNT) fluorophores were systemically delivered to quantify microvascular density after 28 days. Near infrared-II (NIR-II, 1000-1700 nm) imaging of SWNT fluorophores demonstrated that iPSC-EC-seeded aligned scaffolds group showed significantly higher microvascular density than the saline or cells groups. These data suggest that treatment with EC-seeded aligned nanofibrillar scaffolds improved blood perfusion and arteriogenesis, when compared to treatment with cells alone or scaffold alone, and have important implications in the design of therapeutic cell delivery strategies.

  5. Magnetically aligned polymer-nanowire composites for solar energy harvesting

    Science.gov (United States)

    Majewski, Pawel; Pelligra, Candice; Osuji, Chinedum

    2013-03-01

    We present a solution-based approach of producing aligned arrays of ZnO nanowire-polythiophene composites for photovoltaic applications. We employ a two-step hierarchical self-assembly to maximize the efficiency of electron and hole transport in the system. First, we coat the wires with the polymer utilizing nanowire surface-directed crystallization and alignment of the polymer backbones along the long axes of the wires, then we employ magnetic fields to direct the assembly of the composites into the ordered arrays. We present quantitative SAXS data taken in-situ during the alignment process addressing the influence of paramagnetic doping level of ZnO and the magnetic field strength on the quality of the alignment. We compare the electrical conductivity of the aligned arrays of the composites to non-aligned ones and discuss the possible degree of conductivity enhancement upon the alignment in this and in analogous systems. This work is funded by the NSF under DMR-0847534 and DMR-0934520

  6. All about alignment

    CERN Multimedia

    2006-01-01

    The ALICE absorbers, iron wall and superstructure have been installed with great precision. The ALICE front absorber, positioned in the centre of the detector, has been installed and aligned. Weighing more than 400 tonnes, the ALICE absorbers and the surrounding support structures have been installed and aligned with a precision of 1-2 mm, hardly an easy task but a very important one. The ALICE absorbers are made of three parts: the front absorber, a 35-tonne cone-shaped structure, and two small-angle absorbers, long straight cylinder sections weighing 18 and 40 tonnes. The three pieces lined up have a total length of about 17 m. In addition to these, ALICE technicians have installed a 300-tonne iron filter wall made of blocks that fit together like large Lego pieces and a surrounding metal support structure to hold the tracking and trigger chambers. The absorbers house the vacuum chamber and are also the reference surface for the positioning of the tracking and trigger chambers. For this reason, the ab...

  7. Testing the tidal alignment model of galaxy intrinsic alignment

    CERN Document Server

    Blazek, Jonathan; Seljak, Uros

    2011-01-01

    Weak gravitational lensing has become a powerful probe of large-scale structure and cosmological parameters. Precision weak lensing measurements require an understanding of the intrinsic alignment of galaxy ellipticities, which can in turn inform models of galaxy formation. It is hypothesized that elliptical galaxies align with the background tidal field and that this alignment mechanism dominates the correlation between ellipticities on cosmological scales (in the absence of lensing). We use recent large-scale structure measurements from the Sloan Digital Sky Survey to test this picture with several statistics: (1) the correlation between ellipticity and galaxy overdensity, w_{g+}; (2) the intrinsic alignment auto-correlation functions; (3) the correlation functions of curl-free, E, and divergence-free, B, modes (the latter of which is zero in the linear tidal alignment theory); (4) the alignment correlation function, w_g(r_p,theta), a recently developed statistic that generalizes the galaxy correlation func...

  8. Overcoming low-alignment signal contrast induced alignment failure by alignment signal enhancement

    Science.gov (United States)

    Lee, Byeong Soo; Kim, Young Ha; Hwang, Hyunwoo; Lee, Jeongjin; Kong, Jeong Heung; Kang, Young Seog; Paarhuis, Bart; Kok, Haico; de Graaf, Roelof; Weichselbaum, Stefan; Droste, Richard; Mason, Christopher; Aarts, Igor; de Boeij, Wim P.

    2016-03-01

    Overlay is one of the key factors which enables optical lithography extension to 1X node DRAM manufacturing. It is natural that accurate wafer alignment is a prerequisite for good device overlay. However, alignment failures or misalignments are commonly observed in a fab. There are many factors which could induce alignment problems. Low alignment signal contrast is one of the main issues. Alignment signal contrast can be degraded by opaque stack materials or by alignment mark degradation due to processes like CMP. This issue can be compounded by mark sub-segmentation from design rules in combination with double or quadruple spacer process. Alignment signal contrast can be improved by applying new material or process optimization, which sometimes lead to the addition of another process-step with higher costs. If we can amplify the signal components containing the position information and reduce other unwanted signal and background contributions then we can improve alignment performance without process change. In this paper we use ASML's new alignment sensor (as was introduced and released on the NXT:1980Di) and sample wafers with special stacks which can induce poor alignment signal to demonstrate alignment and overlay improvement.

  9. Pareto optimal pairwise sequence alignment.

    Science.gov (United States)

    DeRonne, Kevin W; Karypis, George

    2013-01-01

    Sequence alignment using evolutionary profiles is a commonly employed tool when investigating a protein. Many profile-profile scoring functions have been developed for use in such alignments, but there has not yet been a comprehensive study of Pareto optimal pairwise alignments for combining multiple such functions. We show that the problem of generating Pareto optimal pairwise alignments has an optimal substructure property, and develop an efficient algorithm for generating Pareto optimal frontiers of pairwise alignments. All possible sets of two, three, and four profile scoring functions are used from a pool of 11 functions and applied to 588 pairs of proteins in the ce_ref data set. The performance of the best objective combinations on ce_ref is also evaluated on an independent set of 913 protein pairs extracted from the BAliBASE RV11 data set. Our dynamic-programming-based heuristic approach produces approximated Pareto optimal frontiers of pairwise alignments that contain comparable alignments to those on the exact frontier, but on average in less than 1/58th the time in the case of four objectives. Our results show that the Pareto frontiers contain alignments whose quality is better than the alignments obtained by single objectives. However, the task of identifying a single high-quality alignment among those in the Pareto frontier remains challenging.

  10. Graphene on h-BN: to align or not to align?

    Science.gov (United States)

    Guerra, Roberto; van Wijk, Merel; Vanossi, Andrea; Fasolino, Annalisa; Tosatti, Erio

    2017-06-29

    The contact strength, adhesion and friction, between graphene and an incommensurate crystalline substrate such as h-BN depends on their relative alignment angle θ. The well-established Novaco-McTague (NM) theory predicts for a monolayer graphene on a hard bulk h-BN crystal face a small spontaneous misalignment, here θNM ≃ 0.45 degrees which if realized would be relevant to a host of electronic properties besides the mechanical ones. Because experimental equilibrium is hard to achieve, we inquire theoretically about alignment or misalignment by simulations based on dependable state-of-the-art interatomic force fields. Surprisingly at first, we find compelling evidence for θ = 0, i.e., full energy-driven alignment in the equilibrium state of graphene on h-BN. Two factors drive this deviation from the NM theory. First, graphene is not flat, developing on h-BN a long-wavelength out-of-plane corrugation. Second, h-BN is not hard, releasing its contact stress by planar contractions/expansions that accompany the interface moiré structure. Repeated simulations by artificially forcing graphene to keep flat, and h-BN to keep rigid, indeed yield an equilibrium misalignment similar to θNM as expected. Subsequent sliding simulations show that friction of graphene on h-BN, small and essentially independent of misalignments in the artificial frozen state, strongly increases in the more realistic corrugated, strain-modulated, aligned state.

  11. Driving voltage properties sensitive to microscale liquid crystal orientation pattern in twisted nematic liquid crystal cells

    Science.gov (United States)

    Honma, Michinori; Takahashi, Koki; Yamaguchi, Rumiko; Nose, Toshiaki

    2016-04-01

    We investigated the micropattern-sensitive driving voltage properties of twisted nematic liquid crystal (LC) cells and found that the threshold voltage for inducing the Fréedericksz transition strongly depends on the micropatterned LC molecular orientation state. We discuss the effects of various cell parameters such as the period of the micropattern Λ, the LC layer thickness d, and the twist angle Φ on the threshold voltage. By a computer simulation of the LC molecular orientation, we found that the threshold voltage V th varies in response to the deformation factor Δ (= d 2/Λ2 + Φ2/π2) of the spatially distributed LC molecular orientation. We confirm that V\\text{th}2 is proportional to 1 - Δ from both theoretical and experimental standpoints.

  12. Correlation measurements of light transmittance in polymer dispersed liquid crystals

    Science.gov (United States)

    Maksimyak, P. P.; Nehrych, A. L.

    2015-11-01

    The methods of correlation optics are for the first time applied to study structure of liquid crystal (LC) - polymer (P) composites at various concentrations of LC and P. Their phase correlation function (PCF) was obtained considering LC-P composite as a random phase screen. The amplitude of PCF contains information about number of LC domains and structure of LC director inside of them, while a half-width of this function is connected with a size of these domains. We studied unpowered and powered composite layers with a thickness of 5 μm. As liquid crystal and polymer were used nematic LC E7 from Merck and photopolymer composition NOA65 from Norland. Concentration of polymer φP was varied in a range 10-55 vol. %. In good agreement with previous studies by SEM technique we detected monotone decrease of LC domains with concentration of polymer. With application of electric field, amplitude of PCF behaves differently for the samples with different polymer content. For the samples with φP>35 vol. % (samples having morphology of polymer dispersed LC), this dependence is monotonic. In turn, if φPLC morphology), the amplitude of PCF non-monotonically depends on the applied voltage going through a maximum. The latter fact is explained by transformation of orientational defects of LC phase with the applied voltage.

  13. Onorbit IMU alignment error budget

    Science.gov (United States)

    Corson, R. W.

    1980-01-01

    The Star Tracker, Crew Optical Alignment Sight (COAS), and Inertial Measurement Unit (IMU) from a complex navigation system with a multitude of error sources were combined. A complete list of the system errors is presented. The errors were combined in a rational way to yield an estimate of the IMU alignment accuracy for STS-1. The expected standard deviation in the IMU alignment error for STS-1 type alignments was determined to be 72 arc seconds per axis for star tracker alignments and 188 arc seconds per axis for COAS alignments. These estimates are based on current knowledge of the star tracker, COAS, IMU, and navigation base error specifications, and were partially verified by preliminary Monte Carlo analysis.

  14. Catalyzing alignment processes

    DEFF Research Database (Denmark)

    Lauridsen, Erik Hagelskjær; Jørgensen, Ulrik

    2004-01-01

    in societal and industrial environmental awareness and improvements. The coordination of these elements – covered by the notion of coherence – is seen as the most important mechanism for bringing about a change in environmental impact. The elements comprise of regulatory regimes and available technology......, the networks of environmental professionals that work in the environmental organisation, in consulting and regulatory enforcement, and dominating business cultures. These have previously been identified in the literature as individually significant in relation to the evolving environmental agendas...... time and in combination with other social processes establish more aligned and standardized environmental performance between countries. However, examples of the introduction of environmental management suggests that EMS’ only plays a minor role in developing the actual environmental objectives...

  15. Lunar Alignments - Identification and Analysis

    Science.gov (United States)

    González-García, A. César

    Lunar alignments are difficult to establish given the apparent lack of written accounts clearly pointing toward lunar alignments for individual temples. While some individual cases are reviewed and highlighted, the weight of the proof must fall on statistical sampling. Some definitions for the lunar alignments are provided in order to clarify the targets, and thus, some new tools are provided to try to test the lunar hypothesis in several cases, especially in megalithic astronomy.

  16. GraphAlignment: Bayesian pairwise alignment of biological networks

    Directory of Open Access Journals (Sweden)

    Kolář Michal

    2012-11-01

    Full Text Available Abstract Background With increased experimental availability and accuracy of bio-molecular networks, tools for their comparative and evolutionary analysis are needed. A key component for such studies is the alignment of networks. Results We introduce the Bioconductor package GraphAlignment for pairwise alignment of bio-molecular networks. The alignment incorporates information both from network vertices and network edges and is based on an explicit evolutionary model, allowing inference of all scoring parameters directly from empirical data. We compare the performance of our algorithm to an alternative algorithm, Græmlin 2.0. On simulated data, GraphAlignment outperforms Græmlin 2.0 in several benchmarks except for computational complexity. When there is little or no noise in the data, GraphAlignment is slower than Græmlin 2.0. It is faster than Græmlin 2.0 when processing noisy data containing spurious vertex associations. Its typical case complexity grows approximately as O(N2.6. On empirical bacterial protein-protein interaction networks (PIN and gene co-expression networks, GraphAlignment outperforms Græmlin 2.0 with respect to coverage and specificity, albeit by a small margin. On large eukaryotic PIN, Græmlin 2.0 outperforms GraphAlignment. Conclusions The GraphAlignment algorithm is robust to spurious vertex associations, correctly resolves paralogs, and shows very good performance in identification of homologous vertices defined by high vertex and/or interaction similarity. The simplicity and generality of GraphAlignment edge scoring makes the algorithm an appropriate choice for global alignment of networks.

  17. TWO ALGORITHMS FOR LC1 UNCONSTRAINED OPTIMIZATION

    Institute of Scientific and Technical Information of China (English)

    Wen-yu Sun; R.J.B.de Sampaio; Jin-Yun Yuan

    2000-01-01

    In this paper we present two algorithms for LC1 unconstrained optimization problems which use the second order Dini upper directional derivative. These methods are simple and easy to perform. We discuss the related properties of the iteration function, and establish the global and superlinear convergence of our methods.

  18. LC-MS systems for quantitative bioanalysis

    NARCIS (Netherlands)

    Dongen, W.D. van; Niessen, W.M.A.

    2012-01-01

    LC-MS has become the method-of-choice in small-molecule drug bioanalysis (molecular mass <800 Da) and is also increasingly being applied as an alternative to ligand-binding assays for the bioanalytical determination of biopharmaceuticals. Triple quadrupole MS is the established bioanalytical techniq

  19. LC Quadrature Generation in Integrated Circuits

    DEFF Research Database (Denmark)

    Christensen, Kåre Tais

    2001-01-01

    Today quadrature signals for IQ demodulation are provided through RC polyphase networks, quadrature oscillators or double frequency VCOs. This paper presents a new method for generating quadrature signals in integrated circuits using only inductors and capacitors. This LC quadrature generation me...

  20. Pyro-Align: Sample-Align based Multiple Alignment system for Pyrosequencing Reads of Large Number

    CERN Document Server

    Saeed, Fahad

    2009-01-01

    Pyro-Align is a multiple alignment program specifically designed for pyrosequencing reads of huge number. Multiple sequence alignment is shown to be NP-hard and heuristics are designed for approximate solutions. Multiple sequence alignment of pyrosequenceing reads is complex mainly because of 2 factors. One being the huge number of reads, making the use of traditional heuristics,that scale very poorly for large number, unsuitable. The second reason is that the alignment cannot be performed arbitrarily, because the position of the reads with respect to the original genome is important and has to be taken into account.In this report we present a short description of the multiple alignment system for pyrosequencing reads.

  1. Effects of ferroelectric nanoparticles on ion-transport in a liquid crystal

    Science.gov (United States)

    Garvey, Alfred; Basu, Rajratan

    2015-03-01

    A small quantity of BaTiO3 ferroelectric nanoparticles (FNPs) of 50 nm diameter was doped in a nematic liquid crystal (LC), and the free ion concentration was found to be significantly reduced in the LC +FNP hybrid compared to that of the pure LC. The strong electric fields, due to the permanent dipole moment of the FNPs, trapped some mobile ions, reducing the free ion concentration in the LC media. The reduction of free ions was found to have coherent impacts on the LC's conductivity, rotational viscosity, and electric field-induced nematic switching.

  2. Effects of ferroelectric nanoparticles on ion transport in a liquid crystal

    Science.gov (United States)

    Basu, Rajratan; Garvey, Alfred

    2014-10-01

    A small quantity of BaTiO3 ferroelectric nanoparticles (FNPs) of 50 nm diameter was doped in a nematic liquid crystal (LC), and the free ion concentration was found to be significantly reduced in the LC + FNP hybrid compared to that of the pure LC. The strong electric fields, due to the permanent dipole moment of the FNPs, trapped some mobile ions, reducing the free ion concentration in the LC media. The reduction of free ions was found to have coherent impacts on the LC's conductivity, rotational viscosity, and electric field-induced nematic switching.

  3. Mask alignment system for semiconductor processing

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Aaron P.; Carlson, Charles T.; Weaver, William T.; Grant, Christopher N.

    2017-02-14

    A mask alignment system for providing precise and repeatable alignment between ion implantation masks and workpieces. The system includes a mask frame having a plurality of ion implantation masks loosely connected thereto. The mask frame is provided with a plurality of frame alignment cavities, and each mask is provided with a plurality of mask alignment cavities. The system further includes a platen for holding workpieces. The platen may be provided with a plurality of mask alignment pins and frame alignment pins configured to engage the mask alignment cavities and frame alignment cavities, respectively. The mask frame can be lowered onto the platen, with the frame alignment cavities moving into registration with the frame alignment pins to provide rough alignment between the masks and workpieces. The mask alignment cavities are then moved into registration with the mask alignment pins, thereby shifting each individual mask into precise alignment with a respective workpiece.

  4. The mystery of the vanishing Reinke crystals.

    Science.gov (United States)

    Mesa, Hector; Gilles, Scott; Smith, Sophia; Dachel, Susan; Larson, Wendy; Manivel, J Carlos

    2015-04-01

    Reinke crystals (RC) are pathognomonic of Leydig cells (LCs); they are thought to be rare in normal testes and to occur only in approximately one third of LC tumors. We noticed that crystals present in touch imprint and frozen sections of an LC tumor disappeared after tissue fixation. This phenomenon led us to hypothesize that their reported low frequency in normal and neoplastic LCs may be secondary to degradation/dissolution of the crystals after formalin fixation. Our review of the literature also led us to hypothesize that RC are better preserved after air-drying and alcohol fixation. We collected testicular samples from 21 autopsies including air-dried cytologic preparations and tissue samples that were fixed in alcohol or formalin. We found that RC are common in normal LC but dissolve rapidly in formalin and slowly and only partially in alcohol. The composition of RC is unknown; however, they have been reported to stain specifically for nestin, an intermediate filament expressed mainly in neural and muscle tissue. Because the crystals have only been described in androgen-producing cells, we hypothesized that the crystals may represent a crystallized form of androgenic hormones, hormone complexes, or enzymes involved in their synthesis. We performed immunostains for androgens and enzymes involved in androgenesis. We also performed nestin immunostain to confirm the previous study. The crystals stain specifically with antibodies anti-3β-hydroxysteroid dehydrogenase and are negative for the remaining androgenic enzymes, androgenic hormones, and nestin.

  5. Milestone in the History of Field-Effect Liquid Crystal Displays and Materials

    Science.gov (United States)

    Schadt, Martin

    2009-03-01

    The history of digital electronics would have been very different without the invention of field-effect liquid crystal displays (LCDs) in 1970 and their sophisticated development and implementation into numerous products. Transmissive and reflective LCDs have become a key interface between man and machine. After almost 40 years of interdisciplinary R+D and engineering, today's LCDs enable virtually all display applications, including high definition television. Field-effect LCDs are characterized by flat design, low weight, low driving voltage, design flexibility, compatibility with silicon-on-glass and very low power consumption, especially in reflection. Their polarization-sensitive layer concept is the basis for sandwiching and integration of optical and electronic thin-film functions. The liquid crystal technology has become a fast growing industry over the past 38 years, today surpassing 100 billion, with many spin-offs into new areas. Prerequisite for field-effect LCDs and their large diversification potential is the unique self-organization of liquid crystals. New applications beyond displays based on self-organisation, smart boundary alignment, dedicated liquid crystalline materials and the ability of LCs to respond to electromagnetic fields, including light, are being developed. Examples for new applications are LC polymer thin-film optics, or synergies between LCDs and solid state back-lighting, such as inorganic and organic light emitting diodes (LEDs/OLEDs).

  6. Trends in LC-MS and LC-HRMS analysis and characterization of polyphenols in food

    OpenAIRE

    Lucci, Paolo; Saurina, Javier; Núñez Burcio, Oscar

    2016-01-01

    Polyphenols comprise a large family of naturally occurring secondary metabolites of plant-derived foods and are among the principal micronutrients associated with the health beneficial effects of our diet. Liquid chromatography coupled to mass spectrometry (LC-MS) and, in the last few years, high resolution mass spectrometry (LC-HRMS) is playing an important role in the research of polyphenols, not only for the determination of this family of compounds in food matrices, but also for the chara...

  7. Dye alignment in luminescent solar concentrators: II. Horizontal alignment for energy harvesting in linear polarizers.

    Science.gov (United States)

    Mulder, C L; Reusswig, P D; Beyler, A P; Kim, H; Rotschild, C; Baldo, M A

    2010-04-26

    We describe Linearly Polarized Luminescent Solar Concentrators (LP-LSCs) to replace conventional, purely absorptive, linear polarizers in energy harvesting applications. As a proof of concept, we align 3-(2-Benzothiazolyl)-N,N-diethylumbelliferylamine (Coumarin 6) and 4-dicyanomethyl-6-dimethylaminostiryl-4H-pyran (DCM) dye molecules linearly in the plane of the substrate using a polymerizable liquid crystal host. We show that up to 38% of the photons polarized on the long axis of the dye molecules can be coupled to the edge of the device for an LP-LSC based on Coumarin 6 with an order parameter of 0.52.

  8. RNA Structural Alignments, Part I

    DEFF Research Database (Denmark)

    Havgaard, Jakob Hull; Gorodkin, Jan

    2014-01-01

    Simultaneous alignment and secondary structure prediction of RNA sequences is often referred to as "RNA structural alignment." A class of the methods for structural alignment is based on the principles proposed by Sankoff more than 25 years ago. The Sankoff algorithm simultaneously folds and alig...... the methods based on the Sankoff algorithm. All the practical implementations of the algorithm use heuristics to make them run in reasonable time and memory. These heuristics are also described in this chapter.......Simultaneous alignment and secondary structure prediction of RNA sequences is often referred to as "RNA structural alignment." A class of the methods for structural alignment is based on the principles proposed by Sankoff more than 25 years ago. The Sankoff algorithm simultaneously folds and aligns...... two or more sequences. The advantage of this algorithm over those that separate the folding and alignment steps is that it makes better predictions. The disadvantage is that it is slower and requires more computer memory to run. The amount of computational resources needed to run the Sankoff algorithm...

  9. Lexical alignment in triadic communication.

    Science.gov (United States)

    Foltz, Anouschka; Gaspers, Judith; Thiele, Kristina; Stenneken, Prisca; Cimiano, Philipp

    2015-01-01

    Lexical alignment refers to the adoption of one's interlocutor's lexical items. Accounts of the mechanisms underlying such lexical alignment differ (among other aspects) in the role assigned to addressee-centered behavior. In this study, we used a triadic communicative situation to test which factors may modulate the extent to which participants' lexical alignment reflects addressee-centered behavior. Pairs of naïve participants played a picture matching game and received information about the order in which pictures were to be matched from a voice over headphones. On critical trials, participants did or did not hear a name for the picture to be matched next over headphones. Importantly, when the voice over headphones provided a name, it did not match the name that the interlocutor had previously used to describe the object. Participants overwhelmingly used the word that the voice over headphones provided. This result points to non-addressee-centered behavior and is discussed in terms of disrupting alignment with the interlocutor as well as in terms of establishing alignment with the voice over headphones. In addition, the type of picture (line drawing vs. tangram shape) independently modulated lexical alignment, such that participants showed more lexical alignment to their interlocutor for (more ambiguous) tangram shapes compared to line drawings. Overall, the results point to a rather large role for non-addressee-centered behavior during lexical alignment.

  10. CATO: The Clone Alignment Tool.

    Directory of Open Access Journals (Sweden)

    Peter V Henstock

    Full Text Available High-throughput cloning efforts produce large numbers of sequences that need to be aligned, edited, compared with reference sequences, and organized as files and selected clones. Different pieces of software are typically required to perform each of these tasks. We have designed a single piece of software, CATO, the Clone Alignment Tool, that allows a user to align, evaluate, edit, and select clone sequences based on comparisons to reference sequences. The input and output are designed to be compatible with standard data formats, and thus suitable for integration into a clone processing pipeline. CATO provides both sequence alignment and visualizations to facilitate the analysis of cloning experiments. The alignment algorithm matches each of the relevant candidate sequences against each reference sequence. The visualization portion displays three levels of matching: 1 a top-level summary of the top candidate sequences aligned to each reference sequence, 2 a focused alignment view with the nucleotides of matched sequences displayed against one reference sequence, and 3 a pair-wise alignment of a single reference and candidate sequence pair. Users can select the minimum matching criteria for valid clones, edit or swap reference sequences, and export the results to a summary file as part of the high-throughput cloning workflow.

  11. CATO: The Clone Alignment Tool.

    Science.gov (United States)

    Henstock, Peter V; LaPan, Peter

    2016-01-01

    High-throughput cloning efforts produce large numbers of sequences that need to be aligned, edited, compared with reference sequences, and organized as files and selected clones. Different pieces of software are typically required to perform each of these tasks. We have designed a single piece of software, CATO, the Clone Alignment Tool, that allows a user to align, evaluate, edit, and select clone sequences based on comparisons to reference sequences. The input and output are designed to be compatible with standard data formats, and thus suitable for integration into a clone processing pipeline. CATO provides both sequence alignment and visualizations to facilitate the analysis of cloning experiments. The alignment algorithm matches each of the relevant candidate sequences against each reference sequence. The visualization portion displays three levels of matching: 1) a top-level summary of the top candidate sequences aligned to each reference sequence, 2) a focused alignment view with the nucleotides of matched sequences displayed against one reference sequence, and 3) a pair-wise alignment of a single reference and candidate sequence pair. Users can select the minimum matching criteria for valid clones, edit or swap reference sequences, and export the results to a summary file as part of the high-throughput cloning workflow.

  12. Alignments in the nobelium isotopes

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shi-Zie; XU Fu-Rong; YUAN Cen-Xi; QI Chong

    2009-01-01

    Total-Routhian-Surface calculations have been performed to investigate the deformation and align-ment properties of the No isotopes. It is found that normal deformed and superdeformed states in these nuclei can coexist at low excitation energies. In neutron-deficient No isotopes, the superdeformed shapes can even become the ground states. Moreover, we plotted the kinematic moments of inertia of the No isotopes, which follow very nicely available experimental data. It is noted that, as the rotational frequency increases, align-ments develop at hω=0.2-0.3 MeV. Our calculations show that the occupation of the vj orbital plays an important role in the alignments of the No isotopes.

  13. Alignment of flexible protein structures.

    Science.gov (United States)

    Shatsky, M; Fligelman, Z Y; Nussinov, R; Wolfson, H J

    2000-01-01

    We present two algorithms which align flexible protein structures. Both apply efficient structural pattern detection and graph theoretic techniques. The FlexProt algorithm simultaneously detects the hinge regions and aligns the rigid subparts of the molecules. It does it by efficiently detecting maximal congruent rigid fragments in both molecules and calculating their optimal arrangement which does not violate the protein sequence order. The FlexMol algorithm is sequence order independent, yet requires as input the hypothesized hinge positions. Due its sequence order independence it can also be applied to protein-protein interface matching and drug molecule alignment. It aligns the rigid parts of the molecule using the Geometric Hashing method and calculates optimal connectivity among these parts by graph-theoretic techniques. Both algorithms are highly efficient even compared with rigid structure alignment algorithms. Typical running times on a standard desktop PC (400 MHz) are about 7 seconds for FlexProt and about 1 minute for FlexMol.

  14. The CMS Silicon Tracker Alignment

    CERN Document Server

    Castello, R

    2008-01-01

    The alignment of the Strip and Pixel Tracker of the Compact Muon Solenoid experiment, with its large number of independent silicon sensors and its excellent spatial resolution, is a complex and challenging task. Besides high precision mounting, survey measurements and the Laser Alignment System, track-based alignment is needed to reach the envisaged precision.\\\\ Three different algorithms for track-based alignment were successfully tested on a sample of cosmic-ray data collected at the Tracker Integration Facility, where 15\\% of the Tracker was tested. These results, together with those coming from the CMS global run, will provide the basis for the full-scale alignment of the Tracker, which will be carried out with the first \\emph{p-p} collisions.

  15. Interference Alignment for Secrecy

    CERN Document Server

    Koyluoglu, Onur Ozan; Lai, Lifeng; Poor, H Vincent

    2008-01-01

    This paper studies the frequency/time selective $K$-user Gaussian interference channel with secrecy constraints. Two distinct models, namely the interference channel with confidential messages and the one with an external eavesdropper, are analyzed. The key difference between the two models is the lack of channel state information (CSI) about the external eavesdropper. Using interference alignment along with secrecy pre-coding, it is shown that each user can achieve non-zero secure Degrees of Freedom (DoF) for both cases. More precisely, the proposed coding scheme achieves $\\frac{K-2}{2K-2}$ secure DoF {\\em with probability one} per user in the confidential messages model. For the external eavesdropper scenario, on the other hand, it is shown that each user can achieve $\\frac{K-2}{2K}$ secure DoF {\\em in the ergodic setting}. Remarkably, these results establish the {\\em positive impact} of interference on the secrecy capacity region of wireless networks.

  16. Space Mirror Alignment System

    Science.gov (United States)

    Jau, Bruno M.; McKinney, Colin; Smythe, Robert F.; Palmer, Dean L.

    2011-01-01

    An optical alignment mirror mechanism (AMM) has been developed with angular positioning accuracy of +/-0.2 arcsec. This requires the mirror s linear positioning actuators to have positioning resolutions of +/-112 nm to enable the mirror to meet the angular tip/tilt accuracy requirement. Demonstrated capabilities are 0.1 arc-sec angular mirror positioning accuracy, which translates into linear positioning resolutions at the actuator of 50 nm. The mechanism consists of a structure with sets of cross-directional flexures that enable the mirror s tip and tilt motion, a mirror with its kinematic mount, and two linear actuators. An actuator comprises a brushless DC motor, a linear ball screw, and a piezoelectric brake that holds the mirror s position while the unit is unpowered. An interferometric linear position sensor senses the actuator s position. The AMMs were developed for an Astrometric Beam Combiner (ABC) optical bench, which is part of an interferometer development. Custom electronics were also developed to accommodate the presence of multiple AMMs within the ABC and provide a compact, all-in-one solution to power and control the AMMs.

  17. Downlink Interference Alignment

    CERN Document Server

    Suh, Changho; Tse, David

    2010-01-01

    We develop an interference alignment (IA) technique for a downlink cellular system. In the uplink, IA schemes need channel-state-information exchange across base-stations of different cells, but our downlink IA technique requires feedback only within a cell. As a result, the proposed scheme can be implemented with a few changes to an existing cellular system where the feedback mechanism (within a cell) is already being considered for supporting multi-user MIMO. Not only is our proposed scheme implementable with little effort, it can in fact provide substantial gain especially when interference from a dominant interferer (base-station) is significantly stronger than the remaining interference: it is shown that in the two-isolated cell layout, our scheme provides four-fold gain in throughput performance over a standard multi-user MIMO technique. We show through simulations that our technique provides respectable gain under more realistic scenarios: it gives approximately 55% and 20% gain for a linear cell layou...

  18. Label-free protein sensing by employing blue phase liquid crystal.

    Science.gov (United States)

    Lee, Mon-Juan; Chang, Chung-Huan; Lee, Wei

    2017-03-01

    Blue phases (BPs) are mesophases existing between the isotropic and chiral nematic phases of liquid crystals (LCs). In recent years, blue phase LCs (BPLCs) have been extensively studied in the field of LC science and display technology. However, the application of BPLCs in biosensing has not been explored. In this study, a BPLC-based biosensing technology was developed for the detection and quantitation of bovine serum albumin (BSA). The sensing platform was constructed by assembling an empty cell with two glass slides coated with homeotropic alignment layers and with immobilized BSA atop. The LC cells were heated to isotropic phase and then allowed to cool down to and maintained at distinct BP temperatures for spectral measurements and texture observations. At BSA concentrations below 10(-6) g/ml, we observed that the Bragg reflection wavelength blue-shifted with increasing concentration of BSA, suggesting that the BP is a potentially sensitive medium in the detection and quantitation of biomolecules. By using the BPLC at 37 °C and the same polymorphic material in the smectic A phase at 20 °C, two linear correlations were established for logarithmic BSA concentrations ranging from 10(-9) to 10(-6) g/ml and from 10(-6) to 10(-3) g/ml. Our results demonstrate the potential of BPLCs in biosensing and quantitative analysis of biomolecules.

  19. Crystallization kinetics in liquid crystals with hexagonal precursor phases by calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Padmaja, Sunkara; Ajita, Narayanan; Potukuchi, Dakshina Murthy [Dept. of Physics, Jawaharlal Nehru Technological Univ., Kakinada (India); Srinivasulu, Maddasani; Girish, Sriram Ramchandra [Liquid Crystal Research Centre, Koneru Lakshmaiah Coll. of Engineering, Vaddeswaram (India); Pisipati, Venkata Gopala Krishna Murthy [Dept. of Chemistry, Manipal Inst. of Tech. (India)

    2010-08-15

    Design and characterization of Schiff based liquid crystalline nO.m compounds exhibiting hexagonal smectic phases are reported. Crystallization kinetics investigations are carried out in the liquid crystals (LCs) exhibiting hexagonal ordered orthogonal and tilted precursor LC phases by calorimetry. The Avrami theory is referred and results are analyzed. Influence of molecular ordering, structure, and dimensionality of the LC precursor phase on kinetics is studied. Effect of shape and flexibility of the molecule for nucleation and growth processes is investigated. Varying rate of kinetics reflects upon the transit of the system from constant type to independent type of nucleation. The trends in the Avrami parameter b and exponent n suggest sporadic nucleation. Crystal growth is interpreted as heterogeneous permeation of layered domains (or aggregates) formed by needle shaped calamitic molecules. Calorimetric observations at different crystallization temperatures CT and hold time t infer diffusion mediated crystallization. (orig.)

  20. Alignment-Annotator web server: rendering and annotating sequence alignments.

    Science.gov (United States)

    Gille, Christoph; Fähling, Michael; Weyand, Birgit; Wieland, Thomas; Gille, Andreas

    2014-07-01

    Alignment-Annotator is a novel web service designed to generate interactive views of annotated nucleotide and amino acid sequence alignments (i) de novo and (ii) embedded in other software. All computations are performed at server side. Interactivity is implemented in HTML5, a language native to web browsers. The alignment is initially displayed using default settings and can be modified with the graphical user interfaces. For example, individual sequences can be reordered or deleted using drag and drop, amino acid color code schemes can be applied and annotations can be added. Annotations can be made manually or imported (BioDAS servers, the UniProt, the Catalytic Site Atlas and the PDB). Some edits take immediate effect while others require server interaction and may take a few seconds to execute. The final alignment document can be downloaded as a zip-archive containing the HTML files. Because of the use of HTML the resulting interactive alignment can be viewed on any platform including Windows, Mac OS X, Linux, Android and iOS in any standard web browser. Importantly, no plugins nor Java are required and therefore Alignment-Anotator represents the first interactive browser-based alignment visualization. http://www.bioinformatics.org/strap/aa/ and http://strap.charite.de/aa/. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  1. Magnetic alignment and the Poisson alignment reference system

    Science.gov (United States)

    Griffith, L. V.; Schenz, R. F.; Sommargren, G. E.

    1990-08-01

    Three distinct metrological operations are necessary to align a free-electron laser (FEL): the magnetic axis must be located, a straight line reference (SLR) must be generated, and the magnetic axis must be related to the SLR. This article begins with a review of the motivation for developing an alignment system that will assure better than 100-μm accuracy in the alignment of the magnetic axis throughout an FEL. The 100-μm accuracy is an error circle about an ideal axis for 300 m or more. The article describes techniques for identifying the magnetic axes of solenoids, quadrupoles, and wiggler poles. Propagation of a laser beam is described to the extent of revealing sources of nonlinearity in the beam. Development of a straight-line reference based on the Poisson line, a diffraction effect, is described in detail. Spheres in a large-diameter laser beam create Poisson lines and thus provide a necessary mechanism for gauging between the magnetic axis and the SLR. Procedures for installing FEL components and calibrating alignment fiducials to the magnetic axes of the components are also described. The Poisson alignment reference system should be accurate to 25 μm over 300 m, which is believed to be a factor-of-4 improvement over earlier techniques. An error budget shows that only 25% of the total budgeted tolerance is used for the alignment reference system, so the remaining tolerances should fall within the allowable range for FEL alignment.

  2. Autophagosome Proteins LC3A, LC3B and LC3C Have Distinct Subcellular Distribution Kinetics and Expression in Cancer Cell Lines.

    Directory of Open Access Journals (Sweden)

    Michael I Koukourakis

    Full Text Available LC3s (MAP1-LC3A, B and C are structural proteins of autophagosomal membranes, widely used as biomarkers of autophagy. Whether these three LC3 proteins have a similar biological role in autophagy remains obscure. We examine in parallel the subcellular expression patterns of the three LC3 proteins in a panel of human cancer cell lines, as well as in normal MRC5 fibroblasts and HUVEC, using confocal microscopy and western blot analysis of cell fractions. In the cytoplasm, there was a minimal co-localization between LC3A, B and C staining, suggesting that the relevant autophagosomes are formed by only one out of the three LC3 proteins. LC3A showed a perinuclear and nuclear localization, while LC3B was equally distributed throughout the cytoplasm and localized in the nucleolar regions. LC3C was located in the cytoplasm and strongly in the nuclei (excluding nucleoli, where it extensively co-localized with the LC3A and the Beclin-1 autophagy initiating protein. Beclin 1 is known to contain a nuclear trafficking signal. Blocking nuclear export function by Leptomycin B resulted in nuclear accumulation of all LC3 and Beclin-1 proteins, while Ivermectin that blocks nuclear import showed reduction of accumulation, but not in all cell lines. Since endogenous LC3 proteins are used as major markers of autophagy in clinical studies and cell lines, it is essential to check the specificity of the antibodies used, as the kinetics of these molecules are not identical and may have distinct biological roles. The distinct subcellular expression patterns of LC3s provide a basis for further studies.

  3. Gas barrier properties of bio-inspired Laponite-LC polymer hybrid films.

    Science.gov (United States)

    Tritschler, Ulrich; Zlotnikov, Igor; Fratzl, Peter; Schlaad, Helmut; Grüner, Simon; Cölfen, Helmut

    2016-05-26

    Bio-inspired Laponite (clay)-liquid crystal (LC) polymer composite materials with high clay fractions (>80%) and a high level of orientation of the clay platelets, i.e. with structural features similar to the ones found in natural nacre, have been shown to exhibit a promising behavior in the context of reduced oxygen transmission. Key characteristics of these bio-inspired composite materials are their high inorganic content, high level of exfoliation and orientation of the clay platelets, and the use of a LC polymer forming the organic matrix in between the Laponite particles. Each single feature may be beneficial to increase the materials gas barrier property rendering this composite a promising system with advantageous barrier capacities. In this detailed study, Laponite/LC polymer composite coatings with different clay loadings were investigated regarding their oxygen transmission rate. The obtained gas barrier performance was linked to the quality, respective Laponite content and the underlying composite micro- and nanostructure of the coatings. Most efficient oxygen barrier properties were observed for composite coatings with 83% Laponite loading that exhibit a structure similar to sheet-like nacre. Further on, advantageous mechanical properties of these Laponite/LC polymer composites reported previously give rise to a multifunctional composite system.

  4. LC-MS-based metabolomics: an update.

    Science.gov (United States)

    Fang, Zhong-Ze; Gonzalez, Frank J

    2014-08-01

    Liquid chromatography-mass spectrometry (LC-MS)-based metabolomics can have a major impact in multiple research fields, especially when combined with other technologies, such as stable isotope tracers and genetically modified mice. This review highlights recent applications of metabolomic technology in the study of xenobiotic metabolism and toxicity, and the understanding of disease pathogenesis and therapeutics. Metabolomics has been employed to study metabolism of noscapine, an aryl hydrocarbon receptor antagonist, and to determine the mechanisms of liver toxicities of rifampicin and isoniazid, trichloroethylene, and gemfibrozil. Metabolomics-based insights into the pathogenesis of inflammatory bowel disease, alcohol-induced liver diseases, non-alcoholic steatohepatitis, and farnesoid X receptor signaling pathway-based therapeutic target discovery will also be discussed. Limitations in metabolomics technology such as sample preparation and lack of LC-MS databases and metabolite standards, need to be resolved in order to improve and broaden the application of metabolomic studies.

  5. Shapiro effect in mesoscopic LC circuit

    Institute of Scientific and Technical Information of China (English)

    嵇英华; 罗海梅; 欧阳楚英; 雷敏生

    2002-01-01

    In this paper we consider the movement of an electron in the single electron tunnel process through a mesoscopiccapacitor. The results show that, due to the Coulomb force, there is a threshold voltage Vt in the mesoscopic LC circuit.When the external voltage is lower than the threshold voltage, the tunnel current value is zero, and the Coulomb blockadephenomenon arises. Furthermore, considering that the mesoscopic dimension is comparable to the coherence length inwhich charge carriers retain the phase remembrance, a weak coupling can be produced through the proximity effectof the normal metal electrons of both electrodes of a mesoscopic capacitor. By varying the external voltage, we canobserve the Shapiro current step on the current-voltage characteristic curve of a mesoscopic LC circuit.

  6. Drosophila roadblock and Chlamydomonas Lc7

    Science.gov (United States)

    Bowman, Aaron B.; Patel-King, Ramila S.; Benashski, Sharon E.; McCaffery, J. Michael; Goldstein, Lawrence S.B.; King, Stephen M.

    1999-01-01

    Eukaryotic organisms utilize microtubule-dependent motors of the kinesin and dynein superfamilies to generate intracellular movement. To identify new genes involved in the regulation of axonal transport in Drosophila melanogaster, we undertook a screen based upon the sluggish larval phenotype of known motor mutants. One of the mutants identified in this screen, roadblock (robl), exhibits diverse defects in intracellular transport including axonal transport and mitosis. These defects include intra-axonal accumulations of cargoes, severe axonal degeneration, and aberrant chromosome segregation. The gene identified by robl encodes a 97–amino acid polypeptide that is 57% identical (70% similar) to the 105–amino acid Chlamydomonas outer arm dynein–associated protein LC7, also reported here. Both robl and LC7 have homology to several other genes from fruit fly, nematode, and mammals, but not Saccharomyces cerevisiae. Furthermore, we demonstrate that members of this family of proteins are associated with both flagellar outer arm dynein and Drosophila and rat brain cytoplasmic dynein. We propose that roadblock/LC7 family members may modulate specific dynein functions. PMID:10402468

  7. Isothermal crystallization kinetics of lidocaine in supersaturated lidocaine/polyacrylate pressure sensitive adhesive systems.

    Science.gov (United States)

    Cui, Yong; Frank, Sylvan G

    2005-09-01

    Isothermal crystallization of lidocaine (LC) in supersaturated LC/Duro-Tak 87-2287 (DT2287) polyacrylate pressure sensitive adhesive (PSA) systems has been studied by differential scanning calorimetry (DSC). It was found that crystallization of LC in supersaturated LC/DT2287 systems was governed by the nucleation process, which in turn was dependent on temperature and composition of the systems. A critical temperature T(crit) was found at approximately 26 degrees C, above which the crystallization of LC in LC/DT2287 systems becomes slow. The lack of dependence of T(crit) on the composition of the mixtures indicates that the presence of the PSA affected the kinetics (diffusion) rather than the thermodynamics of the nucleation process. A critical degree of saturation S(crit) of approximately 4 was also found, above which the nucleation rate sharply increases. Kinetic analysis based on the classical theory of nucleation indicates that nucleation of LC in the PSA medium is a diffusion-controlled process. The activation energy of crystallization had a two-phase dependence on temperature suggesting that the mechanism of crystallization may change at the transition temperatures. As the weight fraction of LC increased in the systems, the activation energy of crystallization, DeltaG(c), was minimal at approximately 15 degrees C, indicating that the nucleation of LC in the LC/DT2287 systems is at its fastest rate around this temperature. These fundamental analyses of nucleation and crystallization mechanisms are of practical significance in the design of supersaturated drug delivery systems.

  8. Orbit Alignment in Triple Stars

    Science.gov (United States)

    Tokovinin, Andrei

    2017-08-01

    The statistics of the angle Φ between orbital angular momenta in hierarchical triple systems with known inner visual or astrometric orbits are studied. A correlation between apparent revolution directions proves the partial orbit alignment known from earlier works. The alignment is strong in triples with outer projected separation less than ∼50 au, where the average Φ is about 20^\\circ . In contrast, outer orbits wider than 1000 au are not aligned with the inner orbits. It is established that the orbit alignment decreases with the increasing mass of the primary component. The average eccentricity of inner orbits in well-aligned triples is smaller than in randomly aligned ones. These findings highlight the role of dissipative interactions with gas in defining the orbital architecture of low-mass triple systems. On the other hand, chaotic dynamics apparently played a role in shaping more massive hierarchies. The analysis of projected configurations and triples with known inner and outer orbits indicates that the distribution of Φ is likely bimodal, where 80% of triples have {{Φ }}< 70^\\circ and the remaining ones are randomly aligned.

  9. Periodically-segmented liquid crystal core waveguides

    Science.gov (United States)

    Sharma, Mukesh; Shenoy, M. R.; Sinha, Aloka

    2017-09-01

    We report the fabrication and characterization of electrically-tunable periodically segmented waveguides (PSWs) with different duty cycles of 0.25, 0.33, 0.50 and 0.76, using the nematic liquid crystal 5CB as the guiding layer, and the negative photoresist AZ15nXT as the cladding. The experimental results show that light diffracts and re-focuses periodically on propagation through the liquid crystal (LC) core PSW, when an external voltage is applied to the periodically segmented electrodes. The performance of the fabricated LC core PSWs are analyzed in terms of effective refractive index, output power and duty cycle. The electrically-tunable LC core PSWs have potential application in the realization of optical filters, polarizers and dynamic mode size converters.

  10. Interference forming of transmission by polymer dispersed liquid crystals

    Science.gov (United States)

    Maksimyak, P. P.; Nehrych, A. L.

    2013-12-01

    The methods of correlation optics are for the first time applied to study structure of liquid crystal (LC) - polymer (P) composites at various concentrations of LC and P. Their phase correlation function (PCF) was obtained considering LC-P composite as a random phase screen. The amplitude of PCF contains information about number of LC domains and structure of LC director inside of them, while a half-width of this function is connected with a size of these domains. We studied unpowered and powered composite layers with a thickness of 5 μm. As liquid crystal and polymer were used nematic LC E7 from Merck and photopolymer composition NOA65 from Norland. Concentration of polymer ϕP was varied in a range 10-55 vol. %. In good agreement with previous studies by SEM technique we detected monotone decrease of LC domains with concentration of polymer. With application of electric field, amplitude of PCF behaves differently for the samples with different polymer content. For the samples with ϕPLC), this dependence is monotonic. In turn, if ϕPLC morphology), the amplitude of PCF non-monotonically depends on the applied voltage going through a maximum. The latter fact is explained by transformation of orientational defects of LC phase with the applied voltage.

  11. Aligning for Innovation - Alignment Strategy to Drive Innovation

    Science.gov (United States)

    Johnson, Hurel; Teltschik, David; Bussey, Horace, Jr.; Moy, James

    2010-01-01

    With the sudden need for innovation that will help the country achieve its long-term space exploration objectives, the question of whether NASA is aligned effectively to drive the innovation that it so desperately needs to take space exploration to the next level should be entertained. Authors such as Robert Kaplan and David North have noted that companies that use a formal system for implementing strategy consistently outperform their peers. They have outlined a six-stage management systems model for implementing strategy, which includes the aligning of the organization towards its objectives. This involves the alignment of the organization from the top down. This presentation will explore the impacts of existing U.S. industrial policy on technological innovation; assess the current NASA organizational alignment and its impacts on driving technological innovation; and finally suggest an alternative approach that may drive the innovation needed to take the world to the next level of space exploration, with NASA truly leading the way.

  12. Aligning for Innovation - Alignment Strategy to Drive Innovation

    Science.gov (United States)

    Johnson, Hurel; Teltschik, David; Bussey, Horace, Jr.; Moy, James

    2010-01-01

    With the sudden need for innovation that will help the country achieve its long-term space exploration objectives, the question of whether NASA is aligned effectively to drive the innovation that it so desperately needs to take space exploration to the next level should be entertained. Authors such as Robert Kaplan and David North have noted that companies that use a formal system for implementing strategy consistently outperform their peers. They have outlined a six-stage management systems model for implementing strategy, which includes the aligning of the organization towards its objectives. This involves the alignment of the organization from the top down. This presentation will explore the impacts of existing U.S. industrial policy on technological innovation; assess the current NASA organizational alignment and its impacts on driving technological innovation; and finally suggest an alternative approach that may drive the innovation needed to take the world to the next level of space exploration, with NASA truly leading the way.

  13. Magnetic axis alignment and the Poisson alignment reference system

    Science.gov (United States)

    Griffith, Lee V.; Schenz, Richard F.; Sommargren, Gary E.

    1989-01-01

    Three distinct metrological operations are necessary to align a free-electron laser (FEL): the magnetic axis must be located, a straight line reference (SLR) must be generated, and the magnetic axis must be related to the SLR. This paper begins with a review of the motivation for developing an alignment system that will assure better than 100 micrometer accuracy in the alignment of the magnetic axis throughout an FEL. The paper describes techniques for identifying the magnetic axis of solenoids, quadrupoles, and wiggler poles. Propagation of a laser beam is described to the extent of revealing sources of nonlinearity in the beam. Development and use of the Poisson line, a diffraction effect, is described in detail. Spheres in a large-diameter laser beam create Poisson lines and thus provide a necessary mechanism for gauging between the magnetic axis and the SLR. Procedures for installing FEL components and calibrating alignment fiducials to the magnetic axes of the components are also described. An error budget shows that the Poisson alignment reference system will make it possible to meet the alignment tolerances for an FEL.

  14. Liquid crystal wavefront corrector on silicon

    NARCIS (Netherlands)

    Loktev, M.; Vdovin, G.; Nanver, L.

    2005-01-01

    A reflective-type liquid crystal (LC) wavefront corrector with modal addressing is described. The corrector’s backplane has an array of pixel electrodes interconnected by a network of discrete resistors. The resistive network serves to form the local voltage profile that controls the phase distribut

  15. Crystals in crystals

    DEFF Research Database (Denmark)

    Christensen, Claus H.; Schmidt, I.; Carlsson, A.;

    2005-01-01

    A major factor governing the performance of catalytically active particles supported on a zeolite carrier is the degree of dispersion. It is shown that the introduction of noncrystallographic mesopores into zeolite single crystals (silicalite-1, ZSM-5) may increase the degree of particle dispersion...... of the zeolite particles, particularly after thermal treatment. When using mesoporous zeolites, the particles were evenly distributed throughout the mesopore system of the zeolitic support, even after calcination, leading to nanocrystals within mesoporous zeolite single crystals....

  16. Vertically aligned biaxially textured molybdenum thin films

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Rahul [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Riley, Michael [Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Lee, Sabrina [US Army Armament Research, Development and Engineering Center, Benet Labs, Watervliet, New York 12189 (United States); Lu, Toh-Ming [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2011-09-15

    Vertically aligned, biaxially textured molybdenum nanorods were deposited using dc magnetron sputtering with glancing flux incidence (alpha = 85 degrees with respect to the substrate normal) and a two-step substrate-rotation mode. These nanorods were identified with a body-centered cubic crystal structure. The formation of a vertically aligned biaxial texture with a [110] out-of-plane orientation was combined with a [-110] in-plane orientation. The kinetics of the growth process was found to be highly sensitive to an optimum rest time of 35 seconds for the two-step substrate rotation mode. At all other rest times, the nanorods possessed two separate biaxial textures each tilted toward one flux direction. While the in-plane texture for the vertical nanorods maintains maximum flux capture area, inclined Mo nanorods deposited at alpha = 85 degrees without substrate rotation display a [-1-1-4] in-plane texture that does not comply with the maximum flux capture area argument. Finally, an in situ capping film was deposited with normal flux incidence over the biaxially textured vertical nanorods resulting in a thin film over the porous nanorods. This capping film possessed the same biaxial texture as the nanorods and could serve as an effective substrate for the epitaxial growth of other functional materials.

  17. RF Jitter Modulation Alignment Sensing

    Science.gov (United States)

    Ortega, L. F.; Fulda, P.; Diaz-Ortiz, M.; Perez Sanchez, G.; Ciani, G.; Voss, D.; Mueller, G.; Tanner, D. B.

    2017-01-01

    We will present the numerical and experimental results of a new alignment sensing scheme which can reduce the complexity of alignment sensing systems currently used, while maintaining the same shot noise limited sensitivity. This scheme relies on the ability of electro-optic beam deflectors to create angular modulation sidebands in radio frequency, and needs only a single-element photodiode and IQ demodulation to generate error signals for tilt and translation degrees of freedom in one dimension. It distances itself from current techniques by eliminating the need for beam centering servo systems, quadrant photodetectors and Gouy phase telescopes. RF Jitter alignment sensing can be used to reduce the complexity in the alignment systems of many laser optical experiments, including LIGO and the ALPS experiment.

  18. ELECTROOPTICAL CHARACTERISTICS OF SPACE-INTEGRATED MODULATING STRUCTURES ON TWIST EFFECT IN LIQUID CRYSTALS

    Directory of Open Access Journals (Sweden)

    Yu. V. Razvin

    2014-01-01

    Full Text Available The paper demonstrates that the process of twist LC-pixel switching can be associated not only with a reorientation of liquid crystal molecules in the controlling electric field, but also with the effect of compression of the LC-spiral to the central area through layer thickness. In this case the time of LC-pixel total switching is decreased by almost three orders.

  19. Dispersions of Semiconductor Nanoparticles in Thermotropic Liquid Crystal: From Optical Modification to Assisted Self-Assembly

    OpenAIRE

    Rodarte, Andrea L.

    2014-01-01

    The interaction of semiconducting quantum dot nanoparticles (QDs) within thermotropic liquid crystalline (LC) materials are studied in this thesis. LC materials are ideal for bottom-up organization of nanoparticles as an active matrix that can be externally manipulated via electric or magnetic fields. In addition, the optical properties of QDs can be modified by the surrounding LC resulting in novel devices such as a quantum dot/liquid crystal laser. The first system studies the dispersion of...

  20. Pixel size and pitch measurements of liquid crystal spatial light modulator by optical diffraction

    Indian Academy of Sciences (India)

    Ravinder Kumar Banyal; B Raghavendra Prasad

    2005-08-01

    We present a simple technique for the determination of pixel size and pitch of liquid crystal (LC) based spatial light modulator (SLM). The proposed method is based on optical diffraction from pixelated LC panel that has been modeled as a two-dimensional array of rectangular apertures. A novel yet simple, two-plane measurement technique is implemented to circumvent the difficulty in absolute distance measurement. Experimental results are presented for electrically addressed twisted nematic LC-SLM removed from the display projector.

  1. ELECTROOPTICAL CHARACTERISTICS OF SPACE-INTEGRATED MODULATING STRUCTURES ON TWIST EFFECT IN LIQUID CRYSTALS

    OpenAIRE

    Yu. V. Razvin; V. A. Potachits

    2014-01-01

    The paper demonstrates that the process of twist LC-pixel switching can be associated not only with a reorientation of liquid crystal molecules in the controlling electric field, but also with the effect of compression of the LC-spiral to the central area through layer thickness. In this case the time of LC-pixel total switching is decreased by almost three orders.

  2. Calibration of shaft alignment instruments

    Science.gov (United States)

    Hemming, Bjorn

    1998-09-01

    Correct shaft alignment is vital for most rotating machines. Several shaft alignment instruments, ranging form dial indicator based to laser based, are commercially available. At VTT Manufacturing Technology a device for calibration of shaft alignment instruments was developed during 1997. A feature of the developed device is the similarity to the typical use of shaft alignment instruments i.e. the rotation of two shafts during the calibration. The benefit of the rotation is that all errors of the shaft alignment instrument, for example the deformations of the suspension bars, are included. However, the rotation increases significantly the uncertainty of calibration because of errors in the suspension of the shafts in the developed device for calibration of shaft alignment instruments. Without rotation the uncertainty of calibration is 0.001 mm for the parallel offset scale and 0,003 mm/m for the angular scale. With rotation the uncertainty of calibration is 0.002 mm for the scale and 0.004 mm/m for the angular scale.

  3. Accurate LC peak boundary detection for ¹⁶O/¹⁸O labeled LC-MS data.

    Directory of Open Access Journals (Sweden)

    Jian Cui

    Full Text Available In liquid chromatography-mass spectrometry (LC-MS, parts of LC peaks are often corrupted by their co-eluting peptides, which results in increased quantification variance. In this paper, we propose to apply accurate LC peak boundary detection to remove the corrupted part of LC peaks. Accurate LC peak boundary detection is achieved by checking the consistency of intensity patterns within peptide elution time ranges. In addition, we remove peptides with erroneous mass assignment through model fitness check, which compares observed intensity patterns to theoretically constructed ones. The proposed algorithm can significantly improve the accuracy and precision of peptide ratio measurements.

  4. Liquid Crystal Phase Transition driven three-dimensional Quantum Dot Organization

    Science.gov (United States)

    Rodarte, Andrea L.; Pandolfi, R. J.; Ghosh, S.; Hirst, L. S.

    2013-03-01

    We use a nematic liquid crystal (LC) to create organized assemblies of CdSe/ZnS core/shell quantum dots (QDs). At the isotropic-nematic LC phase transition, ordered domains of nematic LC expel the majority of dispersed QDs into the isotropic domains. The final LC phase produces a series of three dimensional columnar QD assemblies that are situated at defect points in the LC volume. Within each assembly the QD emission is spectrally-red-shifted due to resonant energy transfer. We use this spectral shift as a measure of the inter-dot separation and find that the QDs are packed uniformly in these assemblies over distances of microns between the glass plates of a standard LC cell. In addition, because the QD clusters form at defects, we can deterministically control the location of the assemblies by seeding the LC cell with defect nucleation points. Funding provided by NSF, UC MERI and UC MEXUS.

  5. Photonic Crystal Optical Tweezers

    CERN Document Server

    Wilson, Benjamin K; Bachar, Stephanie; Knouf, Emily; Bendoraite, Ausra; Tewari, Muneesh; Pun, Suzie H; Lin, Lih Y

    2009-01-01

    Non-invasive optical manipulation of particles has emerged as a powerful and versatile tool for biological study and nanotechnology. In particular, trapping and rotation of cells, cell nuclei and sub-micron particles enables unique functionality for various applications such as tissue engineering, cancer research and nanofabrication. We propose and demonstrate a purely optical approach to rotate and align particles using the interaction of polarized light with photonic crystal nanostructures to generate enhanced trapping force. With a weakly focused laser beam we observed efficient trapping and transportation of polystyrene beads with sizes ranging from 10 um down to 190 nm as well as cancer cell nuclei. In addition, we demonstrated alignment of non-spherical particles using a 1-D photonic crystal structure. Bacterial cells were trapped, rotated and aligned with optical intensity as low as 17 uW/um^2. Finite-difference time domain (FDTD) simulations of the optical near-field and far-field above the photonic c...

  6. Crystal science fundamentals

    OpenAIRE

    Ramachandran, V.; Halfpenny, PJ; Roberts, KJ

    2017-01-01

    The fundamentals of crystal science notably crystallography, crystal chemistry, crystal defects, crystal morphology and the surface chemistry of crystals are introduced with particular emphasis on organic crystals.

  7. Sensing Characteristics of A Precision Aligner Using Moire Gratings for Precision Alignment System

    Institute of Scientific and Technical Information of China (English)

    ZHOU Lizhong; Hideo Furuhashi; Yoshiyuki Uchida

    2001-01-01

    Sensing characteristics of a precision aligner using moire gratings for precision alignment sysem has been investigated. A differential moire alignment system and a modified alignment system were used. The influence of the setting accuracy of the gap length and inclination of gratings on the alignment accuracy has been studied experimentally and theoretically. Setting accuracy of the gap length less than 2.5μm is required in modified moire alignment. There is no influence of the gap length on the alignment accuracy in the differential alignment system. The inclination affects alignment accuracies in both differential and modified moire alignment systems.

  8. Fundamental emission characteristics of light-emitting liquid crystal cells with rubrene-doped 4-cyano-4'-pentylbiphenyl

    Science.gov (United States)

    Honma, Michinori; Horiuchi, Takao; Tanimoto, Masashi; Nose, Toshiaki

    2014-06-01

    We have investigated the light emission properties in rubrene-doped nematic liquid crystal (LC) cells from the following three standpoints: (i) effect of the heating temperature during the sample preparation, (ii) role of the emissive LC layer thickness, and (iii) role of different LC types used as the emissive layer. As a result, the light-emitting LC cells simultaneously exhibit the features of electrochemiluminescent cells (the carrier transport is governed by an ionic conduction) as well as of organic light-emitting diodes (the luminance strongly depends on the emissive layer thickness). Furthermore, we report that devices with cyano group containing LCs exhibit higher luminance compared to a fluorinated LC.

  9. Optical devices based on liquid crystal photonic bandgap fibers

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard

    2005-01-01

    In this ph.d. work, an experimental and theoretical study on Liquid Crystal (LC) infiltrated Photonic Crystal Fibers (PCFs) has been carried out. PCFs usually, consists of an air/silica microstructure of air holes arranged in a triangular lattice surrounding a core defect defined by a missing air...... hole. The presence of a LC in the holes of the PCF transforms the fiber from a Total Internal Reflection (TIR) guiding type into a Photonic BandGap (PBG) guiding type, where light is confined to the silica core by coherent scattering from the LC-billed holes. The high dielectric and optical anisotropy...... of LCs combined with the unique waveguiding features of PBG fibers gives the LC filled PCFs unique tunable properties. PBG guidance has been demonstrated for different mesophases of LCs and various functional compact fibers has been demonstrated, which utilitzes the high thermo-optical and electro...

  10. Three-dimensional modeling of nematic liquid crystal micro-optics structures with complex patterned electrodes

    Science.gov (United States)

    Rong, Xing; Kang, Shengwu; Zhang, Xinyu; Ji, An; Xie, Changsheng; Zhang, Tianxu

    2012-11-01

    In this paper, a three-dimensional (3-D) relaxation method is used to model the dynamic response behavior of liquid crystal (LC) directors in LC micro-optics structures with complex patterned electrodes. The method is based on Frank- Oseen continuum elastic theory by using a vectorial representation. This method can deal with liquid crystal structures with arbitrary patterned electrodes, and it is quite computational stability. Different numerical results obtained according the method are as follows: (1) the nematic LC structures with complex patterned electrodes applied by a constant voltage signal, and (2) the nematic LC structures with different thickness of LC layer, and (3) the nematic LC structures with different signal voltage. The typical results include the distribution of LC directors in LC layers, the distribution of electric potential in LC layers, and the distribution of phase retardation. The results show that the method can be used to effectively predict the formation of disclination lines, which has a strong impact on the performance of LC micro-optics structures.

  11. A preliminary clinical report of 2LC reagent for early gastric cancer diagnosis

    Institute of Scientific and Technical Information of China (English)

    Min Li; Xue Zhong Chen; Zhi Xue Lin; Ling Chen

    2000-01-01

    AIM To explore the feasibility of early gastric cancer diagnosis with 2LC reagent, and to establish a grossexploration method for early gastric cancer with the reagent based on the feasibility.METHODS Add 30 mg or 0.3 mL 2LC reagent into 5 mL urinary sample, observe the change of urinary,and analyze the sample on DAO-JIN-UV-260 Ultraviolet-analyzer at 190nm - 700nm, then, record theabsorbance at 490nm. To determine best stage of sample, take some samples on 8:00 pm and 8:00 am,respectively. To select best dosage of 2LC, take the test with different concentrations. To test the effect ofoperation, conduct the experiment in different stages before and after the operation for the patients withgastric cancer. Two parallel samples were taken each time in the whole experiment.RESULTS Red compound produced by some reactions when the 2LC reagent was added into the urinary ofpatients with gastric cancer, and the urine had obvious absorptivity at about 490nm (positive). There was almost no reaction in the urine of other samples (negative). A total of 172 samples were tested, the positiverate of gastric cancer was above 90% in 48 samples before the operation, in which 8 advanced gastric cancerand 9 early stage gastric cancer samples behaved stronger positive reaction. The positive rate of 118 othersamples was less than 10%. The urine taken in the morning was batter than that in the evening. The bestdosage of 2LC was 6 mg/mL for crystal and 0.05 mL/mL for liquid. The test results of gastric cancerpatients with postoperative tumor recrudescence or transfer were positive, and the others were negative.CONCLUSION There is a high feasibility in manipulation simplification, specificity and receptivity of 2LCreagent for early gastric cancer detection, and the characteristics mentioned above will be improved based onthe advanced raw material used and the style of the 2LC reagent. It is an effective gross exploration methodfor early gastric cancer with the 2LC reagent, and can determine

  12. Effects of Temperature and Catalyst Concentration on the Growth of Aligned Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    BAI Xiaodong; LI Dan; WANG Ye; LIANG Ji

    2005-01-01

    The effects of preheating and pyrolysis temperatures and catalyst concentration on the synthesis of aligned carbon nanotubes (CNTs) using ferrocene as the catalyst and xylene as the carbon source in chemical vapor deposition were experimentally studied. The as-grown aligned CNTs were characterized by field emission scanning electron microscopy, transmission electronic microscopy, high-resolution transmission electronic microscopy, and Raman spectroscopy. The growth rate, the diameters, and the degree of crystal structure of the aligned CNTs were all found to depend on the preheating and pyrolysis temperatures and the catalyst concentration. The optimized conditions for the growth of aligned CNTs resulted in a rapid growth rate of 20.4 μm/min, with the CNTs having a good, uniform crystal structure, and clean surfaces with little amorphous carbon. The results also show that higher preheating temperatures and lower ferrocene concentrations favor the growth of single-walled CNTs.

  13. DIDA: Distributed Indexing Dispatched Alignment.

    Directory of Open Access Journals (Sweden)

    Hamid Mohamadi

    Full Text Available One essential application in bioinformatics that is affected by the high-throughput sequencing data deluge is the sequence alignment problem, where nucleotide or amino acid sequences are queried against targets to find regions of close similarity. When queries are too many and/or targets are too large, the alignment process becomes computationally challenging. This is usually addressed by preprocessing techniques, where the queries and/or targets are indexed for easy access while searching for matches. When the target is static, such as in an established reference genome, the cost of indexing is amortized by reusing the generated index. However, when the targets are non-static, such as contigs in the intermediate steps of a de novo assembly process, a new index must be computed for each run. To address such scalability problems, we present DIDA, a novel framework that distributes the indexing and alignment tasks into smaller subtasks over a cluster of compute nodes. It provides a workflow beyond the common practice of embarrassingly parallel implementations. DIDA is a cost-effective, scalable and modular framework for the sequence alignment problem in terms of memory usage and runtime. It can be employed in large-scale alignments to draft genomes and intermediate stages of de novo assembly runs. The DIDA source code, sample files and user manual are available through http://www.bcgsc.ca/platform/bioinfo/software/dida. The software is released under the British Columbia Cancer Agency License (BCCA, and is free for academic use.

  14. Dynamic pattern formation of liquid crystals using binary self-assembled monolayers on an ITO surface under DC voltage.

    Science.gov (United States)

    Ishida, Takao; Oyama, Makiko; Terada, Kei-ichi; Haga, Masa-aki

    2014-12-07

    There have been numerous studies of liquid crystal (LC) convection using sandwich-type LC cells under AC voltage. In contrast to previous LC convection studies under AC voltage, we propose the use of a binary self-assembled monolayer (SAM) with a redox-active Ru complex and insulating octadecyl phosphonic acid (C18) molecules on an indium tin oxide (ITO) surface as the electrode of sandwich-type LC cells under DC bias voltage. This is because the functionalized molecules immobilized on the ITO surface are expected to control the LC orientation and electrical conduction of LC cells, under an exact DC bias voltage. We successfully achieved LC pattern formation using ITO electrodes with binary SAMs in LC cells. Moreover, we confirmed that the LC pattern size was increased by increasing the coverage of the Ru complex in binary SAMs. We consider that a combination of three factors, electrical conduction change, controlling of LC orientation in the initial stage and redox-activity of the Ru-complex, is the reason for LC convection although we cannot fully explain the distribution of these three factors. We believe that our LC pattern formation is promising for new type devices e.g., artificial compound eyes using the LC device technology.

  15. Acute and reproductive effects of Align, an insecticide containing azadirachtin, on the grape berry moth, Lobesia botrana.

    Science.gov (United States)

    Irigaray, F Javier Sáenz-De-Cabezón; Moreno-Grijalba, Fernando; Marco, Vicente; Pérez-Moreno, Ignacio

    2010-01-01

    Azadirachtin, derived from the neem tree, Azadirachta indica A. Juss (Sapindales: Meliaceae), seems promising for use in integrated pest management programs to control a variety of pest species. A commercial formulation of azadirachtin, Align, has been evaluated against different developmental stages of the European grape berry moth, Lobesia botrana Denis and Schiffermüller (Lepidoptera: Tortricidae). When administered orally, Align reduced the fecundity and fertility of adults treated with 1, 5, and 10 mg litre(-1). At the highest doses, fecundity and fertility were zero, but longevity was not affected. An LC(50) of 231.5 mg litre(-1) was obtained when Align was sprayed on eggs less than 1 day old. Hatching of all egg classes was significantly reduced, and this reduction was more pronounced for eggs less than 24 h old. LC(50) values of 2.1 mg litre(-1) for first instars and 18.7 mg litre(-1) for third instars were obtained when Align was present in the diet. Larvae reared on a diet containing different concentrations of Align did not molt into adults at the highest concentrations (0.3, 0.6, 1.2), and 50% molted at the lowest concentration (0.15). Phenotypic effects included inability to molt properly and deformities. The combination of acute toxicity and low, effective concentrations of Align observed in this study could lead to the inclusion of insecticides containing azadirachtin in integrated management programs against this pest.

  16. 取向层厚度及介电常数对 TN-LCD 影响的研究%Effect of thickness and dielectric constant of alignment layer on the TN-LCD

    Institute of Scientific and Technical Information of China (English)

    郭玉强; 王翼飞; 刘建龙; 王森; 马红梅; 孙玉宝

    2016-01-01

    In order to protect the LC and devices with high operating voltage,the thicker thickness of the alignment layer is used.When the thickness of the alignment layer can not be neglected,the in-creasing of the alignment layer’s thickness leads to the increasing of the operating voltage.The influ-ences of the thickness and dielectric constant of the alignment layer on LCD are researched in simula-tion and experiment based on twist nematic liquid crystal display (TN-LCD).The results show that the operating voltage can be reduced effectively when the dielectric constant of the alignment layer is larger than 20,a little effect of the various thickness on the operating voltage can be seen when the di-electric constant is larger than 500.The result has an important significance for reducing the operating voltage of liquid crystal device with high operating voltage.%在具有高驱动电压的液晶显示器中,为了对液晶器件起到保护作用,以采用增加取向层厚度的方法来解决某些显示器件由于驱动电压过高导致的问题。当取向层厚度不可忽略时,随着取向层厚度增加会导致器件驱动电压升高。本文利用扭曲向列相液晶显示器结构,通过模拟和实验分析了取向层厚度对 LCD 的影响以及不同介电常数的取向层对LCD 的影响。结果表明:当取向层的介电常数大于20时,能够有效降低 TN-LCD 驱动电压。当其介电常数大于500时,其厚度变化对驱动电压的影响变得很小。本文结果对降低高驱动电压液晶器件的驱动电压有重要的指导性意义。

  17. General Alignment Concept of the CMS experiment

    CERN Document Server

    Lampen, T

    2006-01-01

    Efficient and accurate track reconstruction requires proper alignment of the tracking devices used. Here we describe the general alignment strategy envisaged for the CMS experiment. The hardware alignment devices of CMS are presented as well as the different track based alignment approaches.

  18. Comparative studies of peak intensities and chromatographic separation of proteolytic digests, PTMs, and intact proteins obtained by nanoLC-ESI MS analysis at room and elevated temperatures.

    Science.gov (United States)

    Moskovets, Eugene V; Ivanov, Alexander R

    2016-06-01

    This work demonstrates that the chromatographic separation performed at highly stabilized elevated temperature results in significant improvements in sensitivity, quantitative accuracy, chromatographic resolution, and run-to-run reproducibility of nanoLC-MS analysis of complex peptides mixtures. A newly developed platform was shown to provide conditions for accurate temperature stabilization and temperature homogeneity when performing nanoLC-ESI MS analysis. We quantitatively assessed and compared the recovery of peptides and small proteins from nanoLC columns at room and elevated temperatures. We found that analyses performed at highly stabilized elevated temperatures led to improved detection sensitivity, reproducibility, and chromatographic resolution in reversed-phase LC separation of unmodified peptides (both hydrophilic and hydrophobic), post-translationally modified peptides (O-phosphorylated), and small intact proteins. The analytical benefits of elevated temperatures for qualitative and quantitative proteomic LC-MS profiling were demonstrated using mixtures of synthetic peptides, tryptic digests of mixtures of model proteins, and digested total lysates of isolated rat kidney mitochondria. The effect of elevated temperature on the ion suppression was also demonstrated. Graphical Abstract A fragment of overlaid LC retention time-m/z planar views demonstrates the improved separation performance in the analysis of a complex peptide mixture at elevated temperature. Retention time-m/z 2D peptide features detected at 60 °C (magenta) were matched and aligned with features detected at room temperature (green).

  19. Alignment method for parabolic trough solar concentrators

    Science.gov (United States)

    Diver, Richard B [Albuquerque, NM

    2010-02-23

    A Theoretical Overlay Photographic (TOP) alignment method uses the overlay of a theoretical projected image of a perfectly aligned concentrator on a photographic image of the concentrator to align the mirror facets of a parabolic trough solar concentrator. The alignment method is practical and straightforward, and inherently aligns the mirror facets to the receiver. When integrated with clinometer measurements for which gravity and mechanical drag effects have been accounted for and which are made in a manner and location consistent with the alignment method, all of the mirrors on a common drive can be aligned and optimized for any concentrator orientation.

  20. Adaptive Processing for Sequence Alignment

    KAUST Repository

    Zidan, Mohammed Affan

    2012-01-26

    Disclosed are various embodiments for adaptive processing for sequence alignment. In one embodiment, among others, a method includes obtaining a query sequence and a plurality of database sequences. A first portion of the plurality of database sequences is distributed to a central processing unit (CPU) and a second portion of the plurality of database sequences is distributed to a graphical processing unit (GPU) based upon a predetermined splitting ratio associated with the plurality of database sequences, where the database sequences of the first portion are shorter than the database sequences of the second portion. A first alignment score for the query sequence is determined with the CPU based upon the first portion of the plurality of database sequences and a second alignment score for the query sequence is determined with the GPU based upon the second portion of the plurality of database sequences.

  1. Laser shaft alignment measurement model

    Science.gov (United States)

    Mo, Chang-tao; Chen, Changzheng; Hou, Xiang-lin; Zhang, Guoyu

    2007-12-01

    Laser beam's track which is on photosensitive surface of the a receiver will be closed curve, when driving shaft and the driven shaft rotate with same angular velocity and rotation direction. The coordinate of arbitrary point which is on the curve is decided by the relative position of two shafts. Basing on the viewpoint, a mathematic model of laser alignment is set up. By using a data acquisition system and a data processing model of laser alignment meter with single laser beam and a detector, and basing on the installation parameter of computer, the state parameter between two shafts can be obtained by more complicated calculation and correction. The correcting data of the four under chassis of the adjusted apparatus moving on the level and the vertical plane can be calculated. This will instruct us to move the apparatus to align the shafts.

  2. Fr-TM-align: a new protein structural alignment method based on fragment alignments and the TM-score

    Directory of Open Access Journals (Sweden)

    Skolnick Jeffrey

    2008-12-01

    Full Text Available Abstract Background Protein tertiary structure comparisons are employed in various fields of contemporary structural biology. Most structure comparison methods involve generation of an initial seed alignment, which is extended and/or refined to provide the best structural superposition between a pair of protein structures as assessed by a structure comparison metric. One such metric, the TM-score, was recently introduced to provide a combined structure quality measure of the coordinate root mean square deviation between a pair of structures and coverage. Using the TM-score, the TM-align structure alignment algorithm was developed that was often found to have better accuracy and coverage than the most commonly used structural alignment programs; however, there were a number of situations when this was not true. Results To further improve structure alignment quality, the Fr-TM-align algorithm has been developed where aligned fragment pairs are used to generate the initial seed alignments that are then refined using dynamic programming to maximize the TM-score. For the assessment of the structural alignment quality from Fr-TM-align in comparison to other programs such as CE and TM-align, we examined various alignment quality assessment scores such as PSI and TM-score. The assessment showed that the structural alignment quality from Fr-TM-align is better in comparison to both CE and TM-align. On average, the structural alignments generated using Fr-TM-align have a higher TM-score (~9% and coverage (~7% in comparison to those generated by TM-align. Fr-TM-align uses an exhaustive procedure to generate initial seed alignments. Hence, the algorithm is computationally more expensive than TM-align. Conclusion Fr-TM-align, a new algorithm that employs fragment alignment and assembly provides better structural alignments in comparison to TM-align. The source code and executables of Fr-TM-align are freely downloadable at: http://cssb.biology.gatech.edu/skolnick/files/FrTMalign/.

  3. XUV ionization of aligned molecules

    Energy Technology Data Exchange (ETDEWEB)

    Kelkensberg, F.; Siu, W.; Gademann, G. [FOM Institute AMOLF, Science Park 104, NL-1098 XG Amsterdam (Netherlands); Rouzee, A.; Vrakking, M. J. J. [FOM Institute AMOLF, Science Park 104, NL-1098 XG Amsterdam (Netherlands); Max-Born-Institut, Max-Born Strasse 2A, D-12489 Berlin (Germany); Johnsson, P. [FOM Institute AMOLF, Science Park 104, NL-1098 XG Amsterdam (Netherlands); Department of Physics, Lund University, Post Office Box 118, SE-221 00 Lund (Sweden); Lucchini, M. [Department of Physics, Politecnico di Milano, Istituto di Fotonica e Nanotecnologie CNR-IFN, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Lucchese, R. R. [Department of Chemistry, Texas A and M University, College Station, Texas 77843-3255 (United States)

    2011-11-15

    New extreme-ultraviolet (XUV) light sources such as high-order-harmonic generation (HHG) and free-electron lasers (FELs), combined with laser-induced alignment techniques, enable novel methods for making molecular movies based on measuring molecular frame photoelectron angular distributions. Experiments are presented where CO{sub 2} molecules were impulsively aligned using a near-infrared laser and ionized using femtosecond XUV pulses obtained by HHG. Measured electron angular distributions reveal contributions from four orbitals and the onset of the influence of the molecular structure.

  4. The alignment-distribution graph

    Science.gov (United States)

    Chatterjee, Siddhartha; Gilbert, John R.; Schreiber, Robert

    1993-01-01

    Implementing a data-parallel language such as Fortran 90 on a distributed-memory parallel computer requires distributing aggregate data objects (such as arrays) among the memory modules attached to the processors. The mapping of objects to the machine determines the amount of residual communication needed to bring operands of parallel operations into alignment with each other. We present a program representation called the alignment distribution graph that makes these communication requirements explicit. We describe the details of the representation, show how to model communication cost in this framework, and outline several algorithms for determining object mappings that approximately minimize residual communication.

  5. Position list word aligned hybrid

    DEFF Research Database (Denmark)

    Deliege, Francois; Pedersen, Torben Bach

    2010-01-01

    Compressed bitmap indexes are increasingly used for efficiently querying very large and complex databases. The Word Aligned Hybrid (WAH) bitmap compression scheme is commonly recognized as the most efficient compression scheme in terms of CPU efficiency. However, WAH compressed bitmaps use a lot...... of storage space. This paper presents the Position List Word Aligned Hybrid (PLWAH) compression scheme that improves significantly over WAH compression by better utilizing the available bits and new CPU instructions. For typical bit distributions, PLWAH compressed bitmaps are often half the size of WAH...

  6. Preprocessing and Analysis of LC-MS-Based Proteomic Data.

    Science.gov (United States)

    Tsai, Tsung-Heng; Wang, Minkun; Ressom, Habtom W

    2016-01-01

    Liquid chromatography coupled with mass spectrometry (LC-MS) has been widely used for profiling protein expression levels. This chapter is focused on LC-MS data preprocessing, which is a crucial step in the analysis of LC-MS based proteomics. We provide a high-level overview, highlight associated challenges, and present a step-by-step example for analysis of data from LC-MS based untargeted proteomic study. Furthermore, key procedures and relevant issues with the subsequent analysis by multiple reaction monitoring (MRM) are discussed.

  7. Anchoring Strength of Thin Aligned-Polymer Films Formed by Liquid Crystalline Monomer

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Ikehata, Seiichiro; Sato, Fumio

    2003-04-01

    We have evaluated the polar anchoring strength of a thin molecule-aligned polymer film formed by a liquid crystalline monomer. The polymer film was obtained by photopolymerization of the monomer oriented by a rubbed polyimide alignment layer in a chamber filled with N2 gas. We fabricated a nematic liquid crystal cell using the thin aligned-polymer films as alignment layers, and then evaluated the anchoring strength of the polymer by measuring the optical retardation curve of the cell driven by voltages. The experimental result showed that the anchoring strength was one order of magnitude lower than that of a conventional rubbed polyimide alignment layer, and decreased with increasing the cure temperature of the monomer film.

  8. Type II band alignment in InAs zinc-blende/wurtzite heterostructured nanowires.

    Science.gov (United States)

    Panda, Jaya Kumar; Chakraborty, Arup; Ercolani, Daniele; Gemmi, Mauro; Sorba, Lucia; Roy, Anushree

    2016-10-14

    In this article we demonstrate type-II band alignment at the wurtzite/zinc-blende hetero-interface in InAs polytype nanowires using resonance Raman measurements. Nanowires were grown with an optimum ratio of the above mentioned phases, so that in the electronic band alignment of such NWs the effect of the difference in the crystal structure dominates over other perturbing effects (e.g. interfacial strain, confinement of charge carriers and band bending due to space charge). Experimental results are compared with the band alignment obtained from density functional theory calculations. In resonance Raman measurements, the excitation energies in the visible range probe the band alignment formed by the E 1 gap of wurtzite and zinc-blende phases. However, we expect our claim to be valid also for band alignment near the fundamental gap at the heterointerface.

  9. Type II band alignment in InAs zinc-blende/wurtzite heterostructured nanowires

    Science.gov (United States)

    Panda, Jaya Kumar; Chakraborty, Arup; Ercolani, Daniele; Gemmi, Mauro; Sorba, Lucia; Roy, Anushree

    2016-10-01

    In this article we demonstrate type-II band alignment at the wurtzite/zinc-blende hetero-interface in InAs polytype nanowires using resonance Raman measurements. Nanowires were grown with an optimum ratio of the above mentioned phases, so that in the electronic band alignment of such NWs the effect of the difference in the crystal structure dominates over other perturbing effects (e.g. interfacial strain, confinement of charge carriers and band bending due to space charge). Experimental results are compared with the band alignment obtained from density functional theory calculations. In resonance Raman measurements, the excitation energies in the visible range probe the band alignment formed by the E 1 gap of wurtzite and zinc-blende phases. However, we expect our claim to be valid also for band alignment near the fundamental gap at the heterointerface.

  10. Fractional RC and LC Electrical Circuits

    Directory of Open Access Journals (Sweden)

    Gómez-Aguilar José Francisco

    2014-04-01

    Full Text Available In this paper we propose a fractional differential equation for the electrical RC and LC circuit in terms of the fractional time derivatives of the Caputo type. The order of the derivative being considered is 0 < ɣ ≤1. To keep the dimensionality of the physical parameters R, L, C the new parameter σ is introduced. This parameter characterizes the existence of fractional structures in the system. A relation between the fractional order time derivative ɣ and the new parameter σ is found. The numeric Laplace transform method was used for the simulation of the equations results. The results show that the fractional differential equations generalize the behavior of the charge, voltage and current depending of the values of ɣ. The classical cases are recovered by taking the limit when ɣ = 1. An analysis in the frequency domain of an RC circuit shows the application and use of fractional order differential equations.

  11. Compact electric-LC resonators for metamaterials

    CERN Document Server

    Withayachumnankul, Withawat; Abbott, Derek

    2010-01-01

    Alternative designs to an electric-LC (ELC) resonator, which is a type of metamaterial inclusion, are presented in this article. Fitting the resonator with an interdigital capacitor (IDC) helps to increase the total capacitance of the structure. In effect, its resonance frequency is shifted downwards. This implies a decreased overall resonator size with respect to its operating wavelength. As a result, the metamaterial, composed of an array of IDC-loaded ELC resonators with their collective electromagnetic response, possesses improved homogeneity and hence is less influenced by diffraction effects of individual cells. The impact of incorporating an IDC into ELC resonators in terms of the electrical size at resonance and other relevant properties are investigated through both simulation and experiment.

  12. Analysis of Dynamic Response of Permittivity in a Liquid Crystal Cell with Flow

    Science.gov (United States)

    Ozaki, R.; Matsuura, K.; Kadowaki, K.; Duong, T. Q.; Moritake, H.

    2016-04-01

    Microwave and millimeter-wave devices including a liquid crystal (LC) are increasingly attractive for the use in adaptive and controllable devices. Various types of microwave phase shifters having an LC transmission line have been studied (e.g. microstripline, coplanar waveguide, and rectangular waveguide). In conventional microwave devices, the response time after removal of voltage is slow because the LC layer in the devices is usually thick. In this study, the time response of the LC permittivity is studied experimentally and theoretically. Experimentally measured response curves having two time constants for decay are examined by using Frank’s continuum theory with and without the backflow effect.

  13. Ordering of solid microparticles at liquid crystal-water interfaces.

    Science.gov (United States)

    Lin, I-Hsin; Koenig, Gary M; de Pablo, Juan J; Abbott, Nicholas L

    2008-12-25

    We report a study of the organization of solid microparticles at oil-water interfaces, where the oil is a thermotropic liquid crystal (LC). The study was motivated by the proposition that microparticle organization and LC ordering would be coupled at these interfaces. Surfactant-functionalized polystyrene microparticles were spread at air-water interfaces at prescribed densities and then raised into contact with supported films of nematic 4-pentyl-4'-cyanobiphenyl (5CB). Whereas this method of sample preparation led to quantitative transfer of microparticles from the air-water interface to an isotropic oil-water interface, forces mediated by the nematic order of 5CB were observed to rapidly displace microparticles laterally across the interface of the water upon contact with nematic 5CB, thus leading to a 65% decrease in the density of microparticles at the LC-water interface. These lateral forces were determined to be caused by microparticle-induced deformation of the LC, the energy of which was estimated to be approximately 10(4) kT. We also observed microparticles transferred to the LC-water interface to assemble into chainlike structures that were not seen when using isotropic oils, indicating the presence of LC-mediated interparticle interactions at this interface. Optical textures of the LC in the vicinity of the microparticles were consistent with formation of topological defects with dipolar symmetry capable of promoting the chaining of the microparticles. The presence of microparticles at the interface also impacted the ordering of the LCs, including a transition from parallel to perpendicular ordering of the LC with increasing microparticle density. These observations, when combined, demonstrate that LC-mediated interactions can direct the assembly of solid microparticles at LC-water interfaces and that the ordering of the LC is also strongly coupled to the presence of microparticles.

  14. Aligned natural inflation with modulations

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kiwoon, E-mail: kchoi@ibs.re.kr [Center for Theoretical Physics of the Universe, Institute for Basic Science (IBS), Daejeon, 34051 (Korea, Republic of); Kim, Hyungjin, E-mail: hjkim06@kaist.ac.kr [Center for Theoretical Physics of the Universe, Institute for Basic Science (IBS), Daejeon, 34051 (Korea, Republic of); Department of Physics, KAIST, Daejeon, 305-701 (Korea, Republic of)

    2016-08-10

    The weak gravity conjecture applied for the aligned natural inflation indicates that generically there can be a modulation of the inflaton potential, with a period determined by sub-Planckian axion scale. We study the oscillations in the primordial power spectrum induced by such modulation, and discuss the resulting observational constraints on the model.

  15. Aligned natural inflation with modulations

    Directory of Open Access Journals (Sweden)

    Kiwoon Choi

    2016-08-01

    Full Text Available The weak gravity conjecture applied for the aligned natural inflation indicates that generically there can be a modulation of the inflaton potential, with a period determined by sub-Planckian axion scale. We study the oscillations in the primordial power spectrum induced by such modulation, and discuss the resulting observational constraints on the model.

  16. Aligning Assessments for COSMA Accreditation

    Science.gov (United States)

    Laird, Curt; Johnson, Dennis A.; Alderman, Heather

    2015-01-01

    Many higher education sport management programs are currently in the process of seeking accreditation from the Commission on Sport Management Accreditation (COSMA). This article provides a best-practice method for aligning student learning outcomes with a sport management program's mission and goals. Formative and summative assessment procedures…

  17. The Rigors of Aligning Performance

    Science.gov (United States)

    2015-06-01

    organization must consider and work closely with its many stakeholders so as to guarantee satisfaction ; this idea is especially important as there is no...define success. Methodology includes a literature review, employee and customer surveys and a Strength, Weaknesses, Opportunities, Threats...bearing in mind customer perceptions. Recommendations include employee training centered on goal alignment, which is vital to highlight the

  18. Identification of forced degradation products of itopride by LC-PDA and LC-MS

    Directory of Open Access Journals (Sweden)

    Payal Joshi

    2011-01-01

    Full Text Available Degradation products of itopride formed under different forced conditions have been identified using LC-PDA and LC-MS techniques. Itopride was subjected to forced degradation under the conditions of hydrolysis, photolysis, oxidation, dry and wet heat, in accordance with the International Conference on Harmonization. The stress solutions were chromatographed on reversed phase C18 (250×4.6 mm, 5 μm column with a mobile phase methanol:water (55:45, v/v at a detection wavelength of 215 nm. Itopride degraded in acid, alkali and oxidative stress conditions. The stability indicating method was developed and validated. The degradation pathway of the drug to products II-VIII is proposed.

  19. Progressive multiple sequence alignments from triplets

    Directory of Open Access Journals (Sweden)

    Stadler Peter F

    2007-07-01

    Full Text Available Abstract Background The quality of progressive sequence alignments strongly depends on the accuracy of the individual pairwise alignment steps since gaps that are introduced at one step cannot be removed at later aggregation steps. Adjacent insertions and deletions necessarily appear in arbitrary order in pairwise alignments and hence form an unavoidable source of errors. Research Here we present a modified variant of progressive sequence alignments that addresses both issues. Instead of pairwise alignments we use exact dynamic programming to align sequence or profile triples. This avoids a large fractions of the ambiguities arising in pairwise alignments. In the subsequent aggregation steps we follow the logic of the Neighbor-Net algorithm, which constructs a phylogenetic network by step-wisely replacing triples by pairs instead of combining pairs to singletons. To this end the three-way alignments are subdivided into two partial alignments, at which stage all-gap columns are naturally removed. This alleviates the "once a gap, always a gap" problem of progressive alignment procedures. Conclusion The three-way Neighbor-Net based alignment program aln3nn is shown to compare favorably on both protein sequences and nucleic acids sequences to other progressive alignment tools. In the latter case one easily can include scoring terms that consider secondary structure features. Overall, the quality of resulting alignments in general exceeds that of clustalw or other multiple alignments tools even though our software does not included heuristics for context dependent (mismatch scores.

  20. A molecular dynamics study of ferroelectric nanoparticles immersed in a nematic liquid crystal.

    Science.gov (United States)

    Pereira, M S S; Canabarro, A A; de Oliveira, I N; Lyra, M L; Mirantsev, L V

    2010-01-01

    A large number of interesting phenomena related to the insertion of colloidal particles in liquid crystals (LC) have recently been reported. Here, we investigate effects caused by the addition of spherically shaped ferroelectric nanoparticles to a nematic liquid crystal. Using molecular dynamics (MD) simulations, the density of LC molecules, the orientational order parameter, and the polar and azimuthal angle profiles are calculated as functions of the distance to the center of the immersed nanoparticle for different temperatures of the system. We observe that the assembly of ferroelectric nanoparticles enhances the nematic order in the LC medium changing many properties of its host above the nematic-isotropic transition temperature T (*) (NI) .

  1. Cylindrical liquid crystal lenses system for autostereoscopic 2D/3D display

    Science.gov (United States)

    Chen, Chih-Wei; Huang, Yi-Pai; Chang, Yu-Cheng; Wang, Po-Hao; Chen, Po-Chuan; Tsai, Chao-Hsu

    2012-06-01

    The liquid crystal lenses system, which could be electrically controlled easily for autostereoscopic 2D/3D switchable display was proposed. The High-Resistance liquid crystal (HRLC) lens utilized less controlled electrodes and coated a high-resistance layer between the controlled-electrodes was proposed and was used in this paper. Compare with the traditional LC lens, the HR-LC Lens could provide smooth electric-potential distribution within the LC layer under driving status. Hence, the proposed HR-LC Lens had less circuit complexity, low driving voltage, and good optical performance also could be obtained. In addition, combining with the proposed driving method called dual-directional overdriving method, the above method could reduce the switching time by applying large voltage onto cell. Consequently, the total switching time could be further reduced to around 2second. It is believed that the LC lens system has high potential in the future.

  2. Tailoring the interfaces between nematic liquid crystal emulsions and aqueous phases via layer-by-layer assembly.

    Science.gov (United States)

    Tjipto, Elvira; Cadwell, Katie D; Quinn, John F; Johnston, Angus P R; Abbott, Nicholas L; Caruso, Frank

    2006-10-01

    We report the assembly of polyelectrolyte multilayer (PEM) films at the interfaces of thermotropic liquid crystal (LC) droplets dispersed in an aqueous phase. Exposure of PEM-coated droplets to surfactant slowed the bipolar-to-radial ordering transition of the LCs by 2 orders of magnitude relative to naked droplets. This shows that PEMs can be used to influence the interactions of analytes with the LC cores of the droplets, allowing tuning of the LC emulsion sensing properties.

  3. Enhanced Nonlinear Optical Effect in Hybrid Liquid Crystal Cells Based on Photonic Crystal

    Science.gov (United States)

    Bugaychuk, Svitlana; Iljin, Andrey; Lytvynenko, Oleg; Tarakhan, Ludmila; Karachevtseva, Lulmila

    2017-07-01

    Nonlinear-optical response of photorefractive hybrid liquid crystal (LC) cells has been studied by means of dynamic holographic technique in two-wave mixing arrangement. The LC cells include nonuniform silicon substrates comprising a micrometer-range photonic crystal. A thin LC layer is set between silicon substrate and a flat glass substrate covered by a transparent (ITO) electrode. A dynamic diffraction grating was induced in the LC volume by the two-wave mixing of laser beams with simultaneous application of DC electric field to the cell. Theoretical model of Raman-Nath self-diffraction was developed. This model allows for calculation of nonlinear optical characteristics in thin samples on the base of two-wave mixing experimental data, and with taking into account light losses on absorption and/or scattering. The hybrid LC cells demonstrate strong nonlinear optical effect, prospective for many applications in electro-optical microsystems, such as SLMs, as well as in multi-channel systems.

  4. Epitaxial order of pentacene on Cu(110)-(2 x 1)O: One dimensional alignment induced by surface corrugation

    Energy Technology Data Exchange (ETDEWEB)

    Koini, M. [Institute of Solid State Physics, Graz University of Technology (Austria)], E-mail: markus.koini@tugraz.at; Haber, T.; Werzer, O. [Institute of Solid State Physics, Graz University of Technology (Austria); Berkebile, S.; Koller, G. [Institute of Physics, Karl-Franzens University Graz (Austria); Oehzelt, M. [Institute of Experimental Physics, Johannes Keppler University Linz (Austria); Ramsey, M.G. [Institute of Physics, Karl-Franzens University Graz (Austria); Resel, R. [Institute of Solid State Physics, Graz University of Technology (Austria)

    2008-11-28

    The structure of a 30 nm thick pentacene film grown by molecular beam deposition on an oxygen passivated Cu(110) single crystal has been investigated ex-situ by X-ray diffraction methods. It is shown that pentacene crystallizes in two known bulk polymorphs with four unique crystal orientations. In all four cases, a principal pentacene direction is aligned along the surface corrugation provided by the Cu(110)-(2 x 1)O reconstruction. Since overlayer and substrate form incommensurate lattices, the results cannot be understood by classical criteria of organic epitaxy and the importance of one dimensional alignment is discussed.

  5. Control of the plasmonic resonance of a graphene coated plasmonic nanoparticle array combined with a nematic liquid crystal

    Science.gov (United States)

    De Sio, Luciano; Cataldi, Ugo; Bürgi, Thomas; Tabiryan, Nelson; Bunning, Timothy J.

    2016-07-01

    We report on the fabrication and characterization of a switchable plasmonic device based on a conductive graphene oxide (cGO) coated plasmonic nanoparticle (NP) array, layered with nematic liquid crystal (NLC) as an active medium. A monolayer of NPs has been immobilized on a glass substrate through electrostatic interaction, and then grown in place using nanochemistry. This monolayer is then coated with a thin (less then 100nm) cGO film which acts simultaneously as both an electro-conductive and active medium. The combination of the conductive NP array with a separate top cover substrate having both cGO and a standard LC alignment layer is used for aligning a NLC film in a hybrid configuration. The system is analysed in terms of morphological and electro-optical properties. The spectral response of the sample characterized after each element is added (air, cGO, NLC) reveals a red-shift of the localized plasmonic resonance (LPR) frequency of approximately 62nm with respect to the NP array surrounded by air. The application of an external voltage (8Vpp) is suitable to modulate (blue shift) the LPR frequency by approximately 22nm.

  6. Doping effect of L-cystine on structural, UV-visible, SHG efficiency, third order nonlinear optical, laser damage threshold and surface properties of cadmium thiourea acetate single crystal

    Science.gov (United States)

    Azhar, S. M.; Anis, Mohd; Hussaini, S. S.; Kalainathan, S.; Shirsat, M. D.; Rabbani, G.

    2017-01-01

    The present article is focused to investigate the influence of L-cystine (LC) on linear-non-linear optical and laser damage threshold of cadmium thiourea acetate (CTA) crystal. The structural parameters of pure and LC doped CTA crystals have been determined using the single crystal X-ray diffraction technique. The functional groups of grown crystals have been identified by means of fourier transform infrared (FT-IR) analysis. The UV-visible spectral analysis has been done in the range of 200-900 nm to ascertain the uplifting influence of LC on optical properties of CTA crystal. The second harmonic generation (SHG) efficiency of LC doped CTA crystal is found to be higher than CTA and KDP crystal. The Z-scan technique has been employed to determine the third order nonlinear optical (TONLO) nature of LC doped CTA crystal at 632.8 nm. The self focusing tendency confirmed the strong kerr lensing ability of LC doped CTA crystal. The TONLO susceptibility (χ3), refraction (n2) and absorption coefficient (β) has been calculated using the Z-scan data. The laser damage threshold of pure and LC doped CTA crystals has been measured using the Q-switched Nd:YAG laser and its is found to be in range of GW/cm2. The surface analysis has been done by means of etching studies.

  7. Toxicity of parasporal crystals of Bacillus thuringiensis subsp. israelensis to mosquitoes.

    Science.gov (United States)

    Tyrell, D J; Davidson, L I; Bulla, L A; Ramoska, W A

    1979-01-01

    Toxicity of Bacillus thuringiensis subsp. israelensis (ONR-60A/WHO 1897) parasporal crystals to three medically important mosquito larvae is described. The numbers of larvae killed are in relation to crystal dry weight. The crystals are lethally toxic to Aedes aegypti Linnaeus (mean 50% lethal concentration [LC50] = 1.9 x 10(-4) micrograms/ml), Culex pipiens var. quinquefasciatus Say (LC50 = 3.7 x 10(-4) micrograms/ml), and Anopheles albimanus Wiedemann (LC50 = 8.0 x 10(-3) micrograms/ml). Purfied crystals of B. thuringiensis subsp. kurstaki, which are toxic to lepidopteran insects, are ineffective against the mosquito larvae. Likewise, B. thuringiensis subsp. israelensis parasporal crystals are not efficacious for larvae of the lepidopteran, Manduca sexta. PMID:44177

  8. On-line coupled LC-LC-GC for irradiation detection in complex lipid matrices

    Energy Technology Data Exchange (ETDEWEB)

    Schulzki, G. (Laboratory Group, Irradiation of Foods and Pharmaceuticals, Alternative Techniques, Inst. for Social Medicine and Epidemiology, Federal Health Office (BGA), Berlin (Germany)); Spiegelberg, A. (Laboratory Group, Irradiation of Foods and Pharmaceuticals, Alternative Techniques, Inst. for Social Medicine and Epidemiology, Federal Health Office (BGA), Berlin (Germany)); Helle, N. (Laboratory Group, Irradiation of Foods and Pharmaceuticals, Alternative Techniques, Inst. for Social Medicine and Epidemiology, Federal Health Office (BGA), Berlin (Germany)); Boegl, K.W. (Laboratory Group, Irradiation of Foods and Pharmaceuticals, Alternative Techniques, Inst. for Social Medicine and Epidemiology, Federal Health Office (BGA), Berlin (Germany)); Schreiber, G.A. (Laboratory Group, Irradiation of Foods and Pharmaceuticals, Alternative Techniques, Inst. for Social Medicine and Epidemiology, Federal Health Office (BGA), Berlin (Germany))

    1993-01-01

    Since sample preparation with HPLC coupled on-line to the GC has been performed for only a few weeks in our laboratory, the results presented give a first look at what can be done by means of this technique. Even difficult samples as the described fish species, where an unequivocal identification regarding an irradiation treatment seemed to become a hopeless enterprise, could be managed. Because of the greater variety of fatty acids in fish ''new'' radiation-induced hydrocarbons were available. According to the theory of Nawar in addition to 16:2 and 17:2 hydrocarbons we have looked for in irradiated meat, further alkadienes appeared in irradiated fish, which were 14:2, 18:2 and 20:2. Analysis of the alkadiene-fraction, transferred to the GC after a two step LC clean up, resulted in an unequivocal identification of all fish samples as well as the fruits and sponge cake. For fruits and sponge cake the detection limit seems to be clearly below 0.5 kGy. It can further be lowered by increasing the amount of lipid whereas the upper limit for a certain LC column has to be determined. In contrast to these samples only qualitative results were obtained for fish. In the case of sponge cake for the first time irradiation of a component of a heat treated food was detected. Further investigations regarding reproducibility, dose dependence and detection limit have to be done. On-line coupled (LC-)LC-GC was proved to be a highly efficient method for analysis of complex samples. In contrast to off-line Florisil column chromatography only a small part of the initial lipid material is needed because the complete hydrocarbon fraction is transferred on-line to the GC. This offers the possibility to analyze even foods with a low fat content like various seafoods. Classification of the hydrocarbon fraction by a two step LC may facilitate the identification of the radiolytic products also if no mass spectrometric detection system is available. (orig./vhe)

  9. Synthesis of Aligned Carbon Nanotubes by Thermal Chemical Vapor Deposition

    Institute of Scientific and Technical Information of China (English)

    LI Gang; ZHOU Ming; MA Weiwei; CAI Lan

    2009-01-01

    Single crystal silicon was found to be very beneficial to the growth of aligned carbon nanotubes by chemical vapor deposition with C2H2 as carbon source. A thin film of Ni served as catalyst was deposited on the Si substrate by the K575X Peltier Cooled High Resolution Sputter Coater before growth. The growth properties of carbon nanotubes were studied as a function of the Ni catalyst layer thickness. The diameter, growth rate and areal density of the carbon nanotubes were controlled by the initial thickness of the catalyst layer. Steric hindrance between nanotubes forces them to grow in well-aligned manner at an initial stage of growth. Transmission electron microscope analysis revealed that nanotubes grew by a tip growth mechanism.

  10. Cooperative Ordering and Kinetics of Cellulose Nanocrystal Alignment in a Magnetic Field.

    Science.gov (United States)

    De France, Kevin J; Yager, Kevin G; Hoare, Todd; Cranston, Emily D

    2016-08-02

    Cellulose nanocrystals (CNCs) are emerging nanomaterials that form chiral nematic liquid crystals above a critical concentration (C*) and additionally orient within electromagnetic fields. The control over CNC alignment is significant for materials processing and end use; to date, magnetic alignment has been demonstrated using only strong fields over extended or arbitrary time scales. This work investigates the effects of comparatively weak magnetic fields (0-1.2 T) and CNC concentration (1.65-8.25 wt %) on the kinetics and degree of CNC ordering using small-angle X-ray scattering. Interparticle spacing, correlation length, and orientation order parameters (η and S) increased with time and field strength following a sigmoidal profile. In a 1.2 T magnetic field for CNC suspensions above C*, partial alignment occurred in under 2 min followed by slower cooperative ordering to achieve nearly perfect alignment in under 200 min (S = -0.499 where S = -0.5 indicates perfect antialignment). At 0.56 T, nearly perfect alignment was also achieved, yet the ordering was 36% slower. Outside of a magnetic field, the order parameter plateaued at 52% alignment (S = -0.26) after 5 h, showcasing the drastic effects of relatively weak magnetic fields on CNC alignment. For suspensions below C*, no magnetic alignment was detected.

  11. Identification of the major constituents of Hypericum perforatum by LC/SPE/NMR and/or LC/MS.

    NARCIS (Netherlands)

    Tatsis, E.C.; Boeren, J.A.; Exarchou, V.; Troganis, A.N.; Vervoort, J.J.M.; Gerothanassis, I.P.

    2007-01-01

    The newly established hyphenated instrumentation of LC/DAD/SPE/NMR and LC/UV/(ESI)MS techniques have been applied for separation and structure verification of the major known constituents present in Greek Hypericum perforatum extracts. The chromatographic separation was performed on a C18 column. Ac

  12. Matrix effects break the LC behavior rule for analytes in LC-MS/MS analysis of biological samples

    Science.gov (United States)

    High-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) are generally accepted as the preferred techniques for detecting and quantitating analytes of interest in biological matrices on the basis of the rule that one chemical compound yields one LC-...

  13. Shuttle onboard IMU alignment methods

    Science.gov (United States)

    Henderson, D. M.

    1976-01-01

    The current approach to the shuttle IMU alignment is based solely on the Apollo Deterministic Method. This method is simple, fast, reliable and provides an accurate estimate for the present cluster to mean of 1,950 transformation matrix. If four or more star sightings are available, the application of least squares analysis can be utilized. The least squares method offers the next level of sophistication to the IMU alignment solution. The least squares method studied shows that a more accurate estimate for the misalignment angles is computed, and the IMU drift rates are a free by-product of the analysis. Core storage requirements are considerably more; estimated 20 to 30 times the core required for the Apollo Deterministic Method. The least squares method offers an intermediate solution utilizing as much data that is available without a complete statistical analysis as in Kalman filtering.

  14. Aligning seminars with Bologna requirements

    DEFF Research Database (Denmark)

    Lueg, Klarissa; Lueg, Rainer; Lauridsen, Ole

    2016-01-01

    Changes in public policy, such as the Bologna Process, require students to be equipped with multifunctional competencies to master relevant tasks in unfamiliar situations. Achieving this goal might imply a change in many curricula toward deeper learning. As a didactical means to achieve deep...... learning results, the authors suggest reciprocal peer tutoring (RPT); as a conceptual framework the authors suggest the SOLO (Structure of Observed Learning Outcomes) taxonomy and constructive alignment as suggested by Biggs and Tang. Our study presents results from the introduction of RPT in a large...... course. The authors find that RPT produces satisfying learning outcomes, active students, and ideal constructive alignments of the seminar content with the exam, the intended learning outcomes, and the requirements of the Bologna Process. Our data, which comprise surveys and evaluations from both faculty...

  15. Prism Window for Optical Alignment

    Science.gov (United States)

    Tang, Hong

    2008-01-01

    A prism window has been devised for use, with an autocollimator, in aligning optical components that are (1) required to be oriented parallel to each other and/or at a specified angle of incidence with respect to a common optical path and (2) mounted at different positions along the common optical path. The prism window can also be used to align a single optical component at a specified angle of incidence. Prism windows could be generally useful for orienting optical components in manufacture of optical instruments. "Prism window" denotes an application-specific unit comprising two beam-splitter windows that are bonded together at an angle chosen to obtain the specified angle of incidence.

  16. Aligned mesoporous architectures and devices.

    Energy Technology Data Exchange (ETDEWEB)

    Brinker, C. Jeffrey; Lu, Yunfeng (University of California Los Angeles, Los Angeles, CA)

    2011-03-01

    This is the final report for the Presidential Early Career Award for Science and Engineering - PECASE (LDRD projects 93369 and 118841) awarded to Professor Yunfeng Lu (Tulane University and University of California-Los Angeles). During the last decade, mesoporous materials with tunable periodic pores have been synthesized using surfactant liquid crystalline as templates, opening a new avenue for a wide spectrum of applications. However, the applications are somewhat limited by the unfavorabe pore orientation of these materials. Although substantial effort has been devoted to align the pore channels, fabrication of mesoporous materials with perpendicular pore channels remains challenging. This project focused on fabrication of mesoporous materials with perpendicularly aligned pore channels. We demonstrated structures for use in water purification, separation, sensors, templated synthesis, microelectronics, optics, controlled release, and highly selective catalysts.

  17. The Cluster Substructure - Alignment Connection

    OpenAIRE

    Plionis, Manolis

    2001-01-01

    Using the APM cluster data we investigate whether the dynamical status of clusters is related to the large-scale structure of the Universe. We find that cluster substructure is strongly correlated with the tendency of clusters to be aligned with their nearest neighbour and in general with the nearby clusters that belong to the same supercluster. Furthermore, dynamically young clusters are more clustered than the overall cluster population. These are strong indications that cluster develop in ...

  18. Alignment in double capture processes

    Energy Technology Data Exchange (ETDEWEB)

    Moretto-Capelle, P.; Benhenni, M.; Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A. (IRSAMC, URA CNRS 770, Univ. Paul Sabatier, 118 rte de Narbonne, 31062 Toulouse Cedex (France))

    1993-06-05

    The electron spectra emitted when a double capture occurs in N[sup 7+]+He and Ne[sup 8+]+He systems at 10 qkeV collisional energy, allow us to determine the angular distributions of the 3[ell]3[ell] [prime] lines through a special spectra fitting procedure which includes interferences between neighbouring states. It is found that the doubly excited states populated in double capture processes are generally aligned.

  19. GASSST: global alignment short sequence search tool

    National Research Council Canada - National Science Library

    Rizk, Guillaume; Lavenier, Dominique

    2010-01-01

    .... Our goal with our new aligner GASSST (Global Alignment Short Sequence Search Tool) is thus 2-fold-achieving high performance with no restrictions on the number of indels with a design that is still effective on long reads...

  20. Grain alignment in starless cores

    Energy Technology Data Exchange (ETDEWEB)

    Jones, T. J.; Bagley, M. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Krejny, M. [Cree Inc., 4600 Silicon Dr., Durham, NC (United States); Andersson, B.-G. [SOFIA Science Center, USRA, Moffett Field, CA (United States); Bastien, P., E-mail: tjj@astro.umn.edu [Centre de recherche en astrophysique du Québec and Départment de Physique, Université de Montréal, Montréal (Canada)

    2015-01-01

    We present near-IR polarimetry data of background stars shining through a selection of starless cores taken in the K band, probing visual extinctions up to A{sub V}∼48. We find that P{sub K}/τ{sub K} continues to decline with increasing A{sub V} with a power law slope of roughly −0.5. Examination of published submillimeter (submm) polarimetry of starless cores suggests that by A{sub V}≳20 the slope for P versus τ becomes ∼−1, indicating no grain alignment at greater optical depths. Combining these two data sets, we find good evidence that, in the absence of a central illuminating source, the dust grains in dense molecular cloud cores with no internal radiation source cease to become aligned with the local magnetic field at optical depths greater than A{sub V}∼20. A simple model relating the alignment efficiency to the optical depth into the cloud reproduces the observations well.

  1. Analyzing algorithms for nonlinear and spatially nonuniform phase shifts in the liquid crystal point diffraction interferometer. 1998 summer research program for high school juniors at the University of Rochester`s Laboratory for Laser Energetics: Student research reports

    Energy Technology Data Exchange (ETDEWEB)

    Jain, N. [Pittsford Sutherland High School, NY (United States)

    1999-03-01

    Phase-shifting interferometry has many advantages, and the phase shifting nature of the Liquid Crystal Point Diffraction Interferometer (LCPDI) promises to provide significant improvement over other current OMEGA wavefront sensors. However, while phase-shifting capabilities improve its accuracy as an interferometer, phase-shifting itself introduces errors. Phase-shifting algorithms are designed to eliminate certain types of phase-shift errors, and it is important to chose an algorithm that is best suited for use with the LCPDI. Using polarization microscopy, the authors have observed a correlation between LC alignment around the microsphere and fringe behavior. After designing a procedure to compare phase-shifting algorithms, they were able to predict the accuracy of two particular algorithms through computer modeling of device-specific phase shift-errors.

  2. Cactus: Algorithms for genome multiple sequence alignment

    OpenAIRE

    Paten, Benedict; Earl, Dent; Nguyen, Ngan; Diekhans, Mark; Zerbino, Daniel; Haussler, David

    2011-01-01

    Much attention has been given to the problem of creating reliable multiple sequence alignments in a model incorporating substitutions, insertions, and deletions. Far less attention has been paid to the problem of optimizing alignments in the presence of more general rearrangement and copy number variation. Using Cactus graphs, recently introduced for representing sequence alignments, we describe two complementary algorithms for creating genomic alignments. We have implemented these algorithms...

  3. An Overview of Multiple Sequence Alignment Systems

    CERN Document Server

    Saeed, Fahad

    2009-01-01

    An overview of current multiple alignment systems to date are described.The useful algorithms, the procedures adopted and their limitations are presented.We also present the quality of the alignments obtained and in which cases(kind of alignments, kind of sequences etc) the particular systems are useful.

  4. Physician-Hospital Alignment in Orthopedic Surgery.

    Science.gov (United States)

    Bushnell, Brandon D

    2015-09-01

    The concept of "alignment" between physicians and hospitals is a popular buzzword in the age of health care reform. Despite their often tumultuous histories, physicians and hospitals find themselves under increasing pressures to work together toward common goals. However, effective alignment is more than just simple cooperation between parties. The process of achieving alignment does not have simple, universal steps. Alignment will differ based on individual situational factors and the type of specialty involved. Ultimately, however, there are principles that underlie the concept of alignment and should be a part of any physician-hospital alignment efforts. In orthopedic surgery, alignment involves the clinical, administrative, financial, and even personal aspects of a surgeon's practice. It must be based on the principles of financial interest, clinical authority, administrative participation, transparency, focus on the patient, and mutual necessity. Alignment can take on various forms as well, with popular models consisting of shared governance and comanagement, gainsharing, bundled payments, accountable care organizations, and other methods. As regulatory and financial pressures continue to motivate physicians and hospitals to develop alignment relationships, new and innovative methods of alignment will also appear. Existing models will mature and evolve, with individual variability based on local factors. However, certain trends seem to be appearing as time progresses and alignment relationships deepen, including regional and national collaboration, population management, and changes in the legal system. This article explores the history, principles, and specific methods of physician-hospital alignment and its critical importance for the future of health care delivery.

  5. Vertically aligned nanostructure scanning probe microscope tips

    Science.gov (United States)

    Guillorn, Michael A.; Ilic, Bojan; Melechko, Anatoli V.; Merkulov, Vladimir I.; Lowndes, Douglas H.; Simpson, Michael L.

    2006-12-19

    Methods and apparatus are described for cantilever structures that include a vertically aligned nanostructure, especially vertically aligned carbon nanofiber scanning probe microscope tips. An apparatus includes a cantilever structure including a substrate including a cantilever body, that optionally includes a doped layer, and a vertically aligned nanostructure coupled to the cantilever body.

  6. Hardware Acceleration of Bioinformatics Sequence Alignment Applications

    NARCIS (Netherlands)

    Hasan, L.

    2011-01-01

    Biological sequence alignment is an important and challenging task in bioinformatics. Alignment may be defined as an arrangement of two or more DNA or protein sequences to highlight the regions of their similarity. Sequence alignment is used to infer the evolutionary relationship between a set of pr

  7. Alignment of lower-limb prostheses.

    Science.gov (United States)

    Zahedi, M S; Spence, W D; Solomonidis, S E; Paul, J P

    1986-04-01

    Alignment of a prosthesis is defined as the position of the socket relative to the other prosthetic components of the limb. During dynamic alignment the prosthetist, using subjective judgment and feedback from the patient, aims to achieve the most suitable limb geometry for best function and comfort. Until recently it was generally believed that a patient could only be satisfied with a unique "optimum alignment." The purpose of this systematic study of lower-limb alignment parameters was to gain an understanding of the factors that make a limb configuration or optimum alignment, acceptable to the patient, and to obtain a measure of the variation of this alignment that would be acceptable to the amputee. In this paper, the acceptable range of alignments for 10 below- and 10 above-knee amputees are established. Three prosthetists were involved in the majority of the 183 below-knee and 100 above-knee fittings, although several other prosthetists were also involved. The effects of each different prosthetist on the established range of alignment for each patient are reported to be significant. It is now established that an amputee can tolerate several alignments ranging in some parameters by as much as 148 mm in shifts and 17 degrees in tilts. This paper describes the method of defining and measuring the alignment of lower-limb prostheses. It presents quantitatively established values for bench alignment position and the range of adjustment required for incorporation into the design of new alignment units.

  8. Aligning Projection Images from Binary Volumes

    NARCIS (Netherlands)

    Bleichrodt, F.; Beenhouwer, J. de; Sijbers, J.; Batenburg, K.J.

    2014-01-01

    In tomography, slight differences between the geometry of the scanner hardware and the geometric model used in the reconstruction lead to alignment artifacts. To exploit high-resolution detectors used in many applications of tomography, alignment of the projection data is essential. Markerless align

  9. A cross-species alignment tool (CAT)

    DEFF Research Database (Denmark)

    Li, Heng; Guan, Liang; Liu, Tao;

    2007-01-01

    sensitive methods which are usually applied in aligning inter-species sequences. RESULTS: Here we present a new algorithm called CAT (for Cross-species Alignment Tool). It is designed to align mRNA sequences to mammalian-sized genomes. CAT is implemented using C scripts and is freely available on the web...

  10. Inferring comprehensible business/ICT alignment rules

    NARCIS (Netherlands)

    Cumps, B.; Martens, D.; De Backer, M.; Haesen, R.; Viaene, S.; Dedene, G.; Baesens, B.; Snoeck, M.

    2009-01-01

    We inferred business rules for business/ICT alignment by applying a novel rule induction algorithm on a data set containing rich alignment information polled from 641 organisations in 7 European countries. The alignment rule set was created using AntMiner+, a rule induction technique with a reputati

  11. Shift dynamics of capillary self-alignment

    NARCIS (Netherlands)

    Arutinov, G.; Mastrangeli, M.; Smits, E.C.P.; Heck, G.V.; Schoo, H.F.M.; Toonder, J.J.M. den; Dietzel, A.H.

    2014-01-01

    This paper describes the dynamics of capillary self-alignment of components with initial shift offsets from matching receptor sites. The analysis of the full uniaxial self-alignment dynamics of foil-based mesoscopic dies from pre-alignment to final settling evidenced three distinct, sequential regim

  12. Strategic Alignment and New Product Development

    DEFF Research Database (Denmark)

    Acur, Nuran; Kandemir, Destan; Boer, Harry

    2012-01-01

    Strategic alignment is widely accepted as a prerequisite for a firm’s success, but insight into the role of alignment in, and its impact on, the new product evelopment (NPD) process and its performance is less well developed. Most publications on this topic either focus on one form of alignment o...

  13. Latest Developments In Liquid Crystal Television Displays

    Science.gov (United States)

    Morozumi, Shinji; Oguchi, Kouichi; Ohshima, Hiroyuki

    1984-06-01

    This paper will discuss developments in liquid crystal (LC) television displays, mainly for pocket-size TV sets. There are two types of LC television displays. One is a simple multiplexing type, and the other is an active matrix type. The former type is an easier way to fabricate large and low-cost LC panels than the latter. However, it has serious drawbacks. The contrast gets lower as the duty ratio gets higher. Therefore the TV image of this type inevitably has rather low contrast and resolution. On the other hand, the active matrix type, which consists of active elements in each pixel, has several advantages in overcoming such problems. The metal oxide semiconductor transistors and the amorphous or polycrystalline Si thin-film transistors (TFTs) have possibilities in this application. A full-color LC display, which can be realized by the combina-tion of color filters and poly Si TFT arrays on a transparent substrate, was proven to have excellent color image, close to that of conventional CRTs. Here, several examples of LC television displays, including color, are shown. Some of them are already on the market, and others will be soon.

  14. Axion Crystals

    CERN Document Server

    Ozaki, Sho

    2016-01-01

    The low-energy effective theories for gapped insulators are classified by three parameters: permittivity $\\epsilon$, permeability $\\mu$, and theta angle $\\theta$. Crystals with periodic $\\epsilon$ are known as photonic crystals. We here study the band structure of photons in a new type of crystals with periodic $\\theta$ (modulo $2\\pi$) in space, which we call the axion crystals. We find that the axion crystals have a number of new properties that the usual photonic crystals do not possess, such as the helicity-dependent photonic band gaps and the nonrelativistic gapless dispersion relation at small momentum. We briefly discuss possible realizations of axion crystals in condensed matter systems as well as high-energy physics.

  15. Electroactive Tissue Scaffolds with Aligned Pores as Instructive Platforms for Biomimetic Tissue Engineering

    Directory of Open Access Journals (Sweden)

    John G. Hardy

    2015-01-01

    Full Text Available Tissues in the body are hierarchically structured composite materials with tissue-specific chemical and topographical properties. Here we report the preparation of tissue scaffolds with macroscopic pores generated via the dissolution of a sacrificial supramolecular polymer-based crystal template (urea from a biodegradable polymer-based scaffold (polycaprolactone, PCL. Furthermore, we report a method of aligning the supramolecular polymer-based crystals within the PCL, and that the dissolution of the sacrificial urea yields scaffolds with macroscopic pores that are aligned over long, clinically-relevant distances (i.e., centimeter scale. The pores act as topographical cues to which rat Schwann cells respond by aligning with the long axis of the pores. Generation of an interpenetrating network of polypyrrole (PPy and poly(styrene sulfonate (PSS in the scaffolds yields electroactive tissue scaffolds that allow the electrical stimulation of Schwann cells cultured on the scaffolds which increases the production of nerve growth factor (NGF.

  16. The application of NLC for detecting solid crystals surface homogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Tomilin, M G, E-mail: mgtomilin@mail.r [St.-Petersburg State University of Information Technologies, Mechanics and Optics, Kronverksky pr. 49, St.-Petersburg, 197101 (Russian Federation)

    2010-11-01

    The goal of the paper is to demonstrate wide fields of new polarizing microscope application based on nematic liquid crystals (LCs) for detecting different solid crystals surface inhomogeneities. Optical polarizing microscope (OPM) based on LCs makes possible to observe the invisible physical fields' distribution on the objects' surfaces. The OPM novelty consists in LC spatial light modulator (SLM) introduction in optical scheme to detect local deformations in real time. LC SLM applied as recording media has to be in direct contact with the surface under investigation. It gives the possibility to detect the invisible physical fields on the surface: intermolecular interactions, electrical, magnetic fields, etc. The theory of LC layer deformations was developed to find the relation between real size of structural defect D and the size of its image D' visualized with NLC layer. OPM method was used for detecting different aspects of surface inhomogeneities for different types of solid crystals. The new results were obtained for twinning boundaries in piezo quartz resonator having industrial application. LC SLM demonstrates non destructive method and better accuracy in comparison with etching, and the simplicity in comparison with x-radiation detecting. LC SLM may be combined with interference, phase-contrast and even near-field microscopes.

  17. 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 ...

  18. Aligning molecules with intense nonresonant laser fields

    DEFF Research Database (Denmark)

    Larsen, J.J.; Safvan, C.P.; Sakai, H.

    1999-01-01

    Molecules in a seeded supersonic beam are aligned by the interaction between an intense nonresonant linearly polarized laser field and the molecular polarizability. We demonstrate the general applicability of the scheme by aligning I2, ICl, CS2, CH3I, and C6H5I molecules. The alignment is probed...... by mass selective two dimensional imaging of the photofragment ions produced by femtosecond laser pulses. Calculations on the degree of alignment of I2 are in good agreement with the experiments. We discuss some future applications of laser aligned molecules....

  19. Subsonic Mechanical Alignment of Irregular Grains

    CERN Document Server

    Lazarian, Alex

    2007-01-01

    We show that grains can be efficiently aligned by interacting with a subsonic gaseous flow. The alignment arises from grains having irregularities that scatter atoms with different efficiency in the right and left directions. The grains tend to align with long axes perpendicular to magnetic field, which corresponds to Davis-Greenstein predictions, but does not involve magnetic field. For rather conservative factors characterizing the grain helicity and scattering efficiency of impinging atoms, the alignment of helical grains is much more efficient than the Gold-type alignment processes.

  20. Imaging the oxidation effects of the Fenton reaction on phospholipids at the interface between aqueous phase and thermotropic liquid crystals.

    Science.gov (United States)

    Zhang, Minmin; Jang, Chang-Hyun

    2015-08-01

    The lipid peroxidation process has attracted much attention because of the growing evidence of its involvement in the pathogenesis of age-related diseases. Herein, we report a simple, label-free method to study the oxidation of phospholipids by the Fenton reaction at the interface between an aqueous phase and immiscible liquid crystals (LCs). The different images produced by the orientation of 4-cyano-4'-pentylbiphenyl (5CB) corresponded to the presence or absence of oxidized 1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DOPG). The oxidation effects of the Fenton reaction on DOPG were evaluated by monitoring the orientational response of liquid crystals upon contact with the oxidized DOPG solutions. DOPG was oxidized into chain-changed products containing hydroxy, carbonyl, or aldehyde groups, resulting in the rearrangement of the phospholipid layer. This induced the orientational transition of LCs from homeotropic to planar states; therefore, a dark to bright optical shift was observed. This shift was due to the Fenton reaction preventing DOPG to induce the orientational alignment of LCs at the aqueous/LC interface. We also used an ultraviolet spectrophotometer to confirm the effects of oxidation on phospholipids by the Fenton reaction. Using this simple method, a new approach for investigating phospholipid oxidation was established with high resolution and easy accessibility.

  1. RevTrans: multiple alignment of coding DNA from aligned amino acid sequences

    DEFF Research Database (Denmark)

    Wernersson, Rasmus; Pedersen, Anders Gorm

    2003-01-01

    The simple fact that proteins are built from 20 amino acids while DNA only contains four different bases, means that the 'signal-to-noise ratio' in protein sequence alignments is much better than in alignments of DNA. Besides this information-theoretical advantage, protein alignments also benefit...... proteins. It is therefore preferable to align coding DNA at the amino acid level and it is for this purpose we have constructed the program RevTrans. RevTrans constructs a multiple DNA alignment by: (i) translating the DNA; (ii) aligning the resulting peptide sequences; and (iii) building a multiple DNA...... alignment by 'reverse translation' of the aligned protein sequences. In the resulting DNA alignment, gaps occur in groups of three corresponding to entire codons, and analogous codon positions are therefore always lined up. These features are useful when constructing multiple DNA alignments for phylogenetic...

  2. Compressive sensing spectrometry based on liquid crystal devices.

    Science.gov (United States)

    August, Yitzhak; Stern, Adrian

    2013-12-01

    We present a new type of compressive spectroscopy technique employing a liquid crystal (LC) phase retarder. A tunable LC cell is used in a manner compliant with the compressive sensing (CS) framework to significantly reduce the spectral scanning effort. The presented optical spectrometer consists of a single LC phase retarder combined with a single photo detector, where the LC phase retarder is used to modulate the input spectrum and the photodiode is used to measure the transmitted spectral signal. Sequences of measurements are taken, where each measurement is done with a different state of the retarder. Then, the set of photodiode measurements is used as input data to a CS solver algorithm. We demonstrate numerally compressive spectral sensing with approximately ten times fewer measurements than with an equivalent conventional spectrometer.

  3. Electroosmotically enabled Electrorheological Effects in a Planar Nematic Crystal Flow

    CERN Document Server

    Dhar, Jayabrata; Chakraborty, Suman

    2016-01-01

    Study of electrokinetics of nematic liquid crystals (LCs) with dissolved impurities hold utmost importance in understanding director distribution characteristics and modified flow rheology. However, no concrete theory for the non-uniform potential and ionic species distribution, due to an induced electrical double layer (EDL) at the LC-substrate interface, derived from fundamental principles have been put forward in this regard. In this work, we have developed coupled governing equations from fundamental free energy considerations for the potential distribution and the director configuration of the nematic LC within the induced electrical double layer which is generated due to certain physico-chemical interactions at the LC-substrate interface. With these considerations, an electroosmotically-enabled nematodynamics for a particular LC, namely, MBBA, with strong planar anchoring at the boundaries is studied. We obtained multiple solution for director configuration, which is an integral characteristics of nemat...

  4. Galaxy alignments: Theory, modelling and simulations

    CERN Document Server

    Kiessling, Alina; Joachimi, Benjamin; Kirk, Donnacha; Kitching, Thomas D; Leonard, Adrienne; Mandelbaum, Rachel; Schäfer, Björn Malte; Sifón, Cristóbal; Brown, Michael L; Rassat, Anais

    2015-01-01

    The shapes of galaxies are not randomly oriented on the sky. During the galaxy formation and evolution process, environment has a strong influence, as tidal gravitational fields in large-scale structure tend to align the shapes and angular momenta of nearby galaxies. Additionally, events such as galaxy mergers affect the relative alignments of galaxies throughout their history. These "intrinsic galaxy alignments" are known to exist, but are still poorly understood. This review will offer a pedagogical introduction to the current theories that describe intrinsic galaxy alignments, including the apparent difference in intrinsic alignment between early- and late-type galaxies and the latest efforts to model them analytically. It will then describe the ongoing efforts to simulate intrinsic alignments using both $N$-body and hydrodynamic simulations. Due to the relative youth of this field, there is still much to be done to understand intrinsic galaxy alignments and this review summarises the current state of the ...

  5. FOGSAA: Fast Optimal Global Sequence Alignment Algorithm

    Science.gov (United States)

    Chakraborty, Angana; Bandyopadhyay, Sanghamitra

    2013-04-01

    In this article we propose a Fast Optimal Global Sequence Alignment Algorithm, FOGSAA, which aligns a pair of nucleotide/protein sequences faster than any optimal global alignment method including the widely used Needleman-Wunsch (NW) algorithm. FOGSAA is applicable for all types of sequences, with any scoring scheme, and with or without affine gap penalty. Compared to NW, FOGSAA achieves a time gain of (70-90)% for highly similar nucleotide sequences (> 80% similarity), and (54-70)% for sequences having (30-80)% similarity. For other sequences, it terminates with an approximate score. For protein sequences, the average time gain is between (25-40)%. Compared to three heuristic global alignment methods, the quality of alignment is improved by about 23%-53%. FOGSAA is, in general, suitable for aligning any two sequences defined over a finite alphabet set, where the quality of the global alignment is of supreme importance.

  6. Alignment method for solar collector arrays

    Science.gov (United States)

    Driver, Jr., Richard B

    2012-10-23

    The present invention is directed to an improved method for establishing camera fixture location for aligning mirrors on a solar collector array (SCA) comprising multiple mirror modules. The method aligns the mirrors on a module by comparing the location of the receiver image in photographs with the predicted theoretical receiver image location. To accurately align an entire SCA, a common reference is used for all of the individual module images within the SCA. The improved method can use relative pixel location information in digital photographs along with alignment fixture inclinometer data to calculate relative locations of the fixture between modules. The absolute locations are determined by minimizing alignment asymmetry for the SCA. The method inherently aligns all of the mirrors in an SCA to the receiver, even with receiver position and module-to-module alignment errors.

  7. Aligning Sequences by Minimum Description Length

    Directory of Open Access Journals (Sweden)

    John S. Conery

    2008-01-01

    Full Text Available This paper presents a new information theoretic framework for aligning sequences in bioinformatics. A transmitter compresses a set of sequences by constructing a regular expression that describes the regions of similarity in the sequences. To retrieve the original set of sequences, a receiver generates all strings that match the expression. An alignment algorithm uses minimum description length to encode and explore alternative expressions; the expression with the shortest encoding provides the best overall alignment. When two substrings contain letters that are similar according to a substitution matrix, a code length function based on conditional probabilities defined by the matrix will encode the substrings with fewer bits. In one experiment, alignments produced with this new method were found to be comparable to alignments from CLUSTALW. A second experiment measured the accuracy of the new method on pairwise alignments of sequences from the BAliBASE alignment benchmark.

  8. LC, MSn and LC-MS/MS studies for the characterization of degradation products of amlodipine

    Institute of Scientific and Technical Information of China (English)

    Ravi N. Tiwari; Nishit Shah; Vikas Bhalani; Anand Mahajan

    2015-01-01

    In the present study, comprehensive stress testing of amlodipine (AM) was carried out according to International Conference on Harmonization (ICH) Q1A(R2) guideline. AM was subjected to acidic, neutral and alkaline hydrolysis, oxidation, photolysis and thermal stress conditions. The drug showed instability in acidic and alkaline conditions, while it remained stable to neutral, oxidative, light and thermal stress. A total of nine degradation products (DPs) were formed from AM, which could be separated by the developed gradient LC method on a C18 column. The products formed under various stress conditions were investigated by LC–MS/MS analysis. The previously developed LC method was suitably modified for LC–MS/MS studies by replacing phosphate buffer with ammonium acetate buffer of the same concentration (pH 5.0). A complete fragmentation pathway of the drug was first established to characterize all the degradation products using LC–MS/MS and multi-stage mass (MSn) fragmentation studies. The obtained mass values were used to study elemental compositions, and the total information helped with the identification of DPs, along with its degradation pathway.

  9. Pupil Alignment Measuring Technique and Alignment Reference for Instruments or Optical Systems

    Science.gov (United States)

    Hagopian, John G.

    2010-01-01

    A technique was created to measure the pupil alignment of instruments in situ by measuring calibrated pupil alignment references (PARs) in instruments. The PAR can also be measured using an alignment telescope or an imaging system. PAR allows the verification of the science instrument (SI) pupil alignment at the integrated science instrument module (ISIM) level of assembly at ambient and cryogenic operating temperature. This will allow verification of the ISIM+SI alignment, and provide feedback to realign the SI if necessary.

  10. Characterization of reactively sputtered c-axis aligned nanocrystalline InGaZnO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Lynch, David M.; Zhu, Bin; Ast, Dieter G.; Thompson, Michael O. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States); Levin, Barnaby D. A. [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Muller, David A. [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Kavli Institute for Nanoscale Science, Cornell University, Ithaca, New York 14853 (United States); Greene, Raymond G. [Corning Incorporated, Corning, New York 14831 (United States)

    2014-12-29

    Crystallinity and texturing of RF sputtered c-axis aligned crystal InGaZnO{sub 4} (CAAC IGZO) thin films were quantified using X-ray diffraction techniques. Above 190 °C, nanocrystalline films with an X-ray peak at 2θ = 30° (009 planes) developed with increasing c-axis normal texturing up to 310 °C. Under optimal conditions (310 °C, 10% O{sub 2}), films exhibited a c-axis texture full-width half-maximum of 20°. Cross-sectional high-resolution transmission electron microscopy confirmed these results, showing alignment variation of ±9° over a 15 × 15 nm field of view and indicating formation of much larger aligned domains than previously reported. At higher deposition temperatures, c-axis alignment was gradually lost as polycrystalline films developed.

  11. Magnetic fields in long-range alignment of functional hybrid soft materials

    Science.gov (United States)

    Majewski, Pawel; Gopinadhan, Manesh; Pelligra, Candice; Zhang, Shanju; Pfefferle, Lisa; Osuji, Chinedum

    2012-02-01

    We present a magnetic field-based method to impose long range order in self-assembled soft materials including polymer-nanowire composites, block copolymers and surfactant mesophases. We discuss the broad utility of this approach, indicating its advantages and limitations. Our method yields highly anisotropic materials with quality of alignment in many cases comparable to that of single crystals as assessed by X-ray scattering techniques. We take advantage of the high fidelity of alignment to systematically explore and characterize the anisotropic properties of these materials. We present a perspective for improving electron and hole transport, as well as exciton utilization in magnetically doped ZnO nanowire-polythiophene composites for photovoltaic applications by global alignment of the nanowires. For block copolymers, we focus on enhancing Li-ion transport in membranes with self-assembled cylindrical and lamellar morphology by alignment of the Li-conducting PEO domains.

  12. Damped and thermal motion of large, laser-aligned molecules in droplet beams

    Energy Technology Data Exchange (ETDEWEB)

    Starodub, D; Doak, B; Schmidt, K; Weierstall, U; Wu, J; Spence, J; Howells, M; Marcus, M; Shapiro, D; Barty, A; Chapman, H

    2005-09-29

    We consider a monodispersed Rayleigh droplet beam of water droplets doped with proteins. An intense infrared laser is used to align these droplets. The arrangement has been proposed for electron and X-ray diffraction studies of proteins which are difficult to crystallize. This paper considers the effect of thermal fluctuations on the angular spread of alignment in thermal equilibrium, and relaxation phenomena, particularly the damping of oscillations excited as the molecules enter the field. The possibility of adiabatic alignment is also considered. We find that damping times in high pressure gas cell as used in X-ray diffraction experiments are short compared to the time taken for molecules to traverse the beam, and that a suitably shaped field might be used for electron diffraction experiments in vacuum to provide adiabatic alignment, thus obviating the need for a damping gas cell.

  13. MEANS FOR DETERMINING CENTRIFUGE ALIGNMENT

    Science.gov (United States)

    Smith, W.Q.

    1958-08-26

    An apparatus is presented for remotely determining the alignment of a centrifuge. The centrifage shaft is provided with a shoulder, upon which two followers ride, one for detecting radial movements, and one upon the shoulder face for determining the axial motion. The followers are attached to separate liquid filled bellows, and a tube connects each bellows to its respective indicating gage at a remote location. Vibrations produced by misalignment of the centrifuge shaft are transmitted to the bellows, and tbence through the tubing to the indicator gage. This apparatus is particularly useful for operation in a hot cell where the materials handled are dangerous to the operating personnel.

  14. Aligned interactions in cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Kempa, J., E-mail: kempa@pw.plock.pl [Warsaw University of Technology Branch Plock (Poland)

    2015-12-15

    The first clean Centauro was found in cosmic rays years many ago at Mt Chacaltaya experiment. Since that time, many people have tried to find this type of interaction, both in cosmic rays and at accelerators. But no one has found a clean cases of this type of interaction.It happened finally in the last exposure of emulsion at Mt Chacaltaya where the second clean Centauro has been found. The experimental data for both the Centauros and STRANA will be presented and discussed in this paper. We also present our comments to the intriguing question of the existence of a type of nuclear interactions at high energy with alignment.

  15. Supramolecular liquid crystal displays : construction and applications

    NARCIS (Netherlands)

    Hoogboom, Joannes Theodorus Valentinus

    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 pos

  16. Ultrabroadband terahertz spectroscopy of a liquid crystal

    DEFF Research Database (Denmark)

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

    2012-01-01

    present the frequency dependent index of refraction and the absorption coefficients of the nematic liquid crystal 5CB over a frequency range from 0.3 THz to 15 THz using a dispersion-free THz time-domain spectrometer system based on two-color plasma generation and air biased coherent detection (ABCD). We......Liquid crystals (LCs) are becoming increasingly important for applications in the terahertz frequency range. A detailed understanding of the spectroscopic parameters of these materials over a broad frequency range is crucial in order to design customized LC mixtures for improved performance. We...

  17. Switchable random laser from dye-doped polymer dispersed liquid crystal waveguides

    NARCIS (Netherlands)

    Xiao, Shumin; Song, Qinghai; Wang, Feng; Liu, Liying; Liu, Jianhua; Xu, Lei

    2007-01-01

    A dye-doped polymer-dispersed liquid crystal (PDLC) film has been fabricated for random lasing action. In this PDLC film, the sizes of most liquid crystal (LC) droplets ranged from 200 to 500 nm. When the sample is optically pumped, ultrahigh Q (>10 000) lasing modes and a collimated laser beam can

  18. RNA Crystallization

    Science.gov (United States)

    Golden, Barbara L.; Kundrot, Craig E.

    2003-01-01

    RNA molecules may be crystallized using variations of the methods developed for protein crystallography. As the technology has become available to syntheisize and purify RNA molecules in the quantities and with the quality that is required for crystallography, the field of RNA structure has exploded. The first consideration when crystallizing an RNA is the sequence, which may be varied in a rational way to enhance crystallizability or prevent formation of alternate structures. Once a sequence has been designed, the RNA may be synthesized chemically by solid-state synthesis, or it may be produced enzymatically using RNA polymerase and an appropriate DNA template. Purification of milligram quantities of RNA can be accomplished by HPLC or gel electrophoresis. As with proteins, crystallization of RNA is usually accomplished by vapor diffusion techniques. There are several considerations that are either unique to RNA crystallization or more important for RNA crystallization. Techniques for design, synthesis, purification, and crystallization of RNAs will be reviewed here.

  19. Influence of ZnO nanostructures in liquid crystal interfaces for bistable switching applications

    Science.gov (United States)

    Pal, Kaushik; Zhan, Bihong; Madhu Mohan, M. L. N.; Schirhagl, Romana; Wang, Guoping

    2015-12-01

    The controlled fabrication of nanometer-scale objects is without doubt one of the central issues in current science and technology. In this article, we exhibit a simple, one-step bench top synthesis of zinc oxide nano-tetrapods and nano-spheres which were tailored by the facial growth of nano-wires (diameter ≈ 24 nm; length ≈ 118 nm) and nano-cubes (≈395 nm edge) to nano-sphere (diameter ≈ 585 nm) appeaded. The possibilities of inexpensive, simple solvo-chemical synthesis of nanostructures were considered. In this article, a successful attempt has been made that ZnO nano-structures dispersed on well aligned hydrogen bonded liquid crystals (HBLC) comprising azelaic acid (AC) with p-n-alkyloxy benzoic acid (nBAO) by varying the respective alkyloxy carbon number (n = 5). The dispersion of nanomaterials with HBLC is an effective route to enhance the existing functionalities. A series of these composite materials were analyzed by polarizing optical microscope's electro-optical switching. An interesting feature of AC + nBAO is the inducement of tilted smectic G phase with increasing carbon chain length. Phase diagrams of the above hybrid ZnO nanomaterial influenced LC complex and pure LC were constructed and compared. The switching times, the contrast ratio and spontaneous polarization of the nanostructures-HBLC composite film were carried out by systematic investigation. The sample preparation parameters, such as the curing time and curing intensity were optimized. The critical applied voltage to achieve the switching bi-stability of our device is only 4.5 V, which is approximately twice its threshold voltage for Freedericksz transition. This performance puts the hybrid structure at the top level in the state of the art in application oriented research in optics of liquid crystalline composite materials.

  20. Improvement of Response Performance of Liquid Crystal Optical Devices by using a Low Viscosity Component

    Institute of Scientific and Technical Information of China (English)

    PENG Zeng-Hui; LIU Yong-Gang; YAO Li-Shuang; CAO Zhao-Liang; MU Quan-Quan; HU Li-Fa; LU Xing-Hai; XUAN Li; ZHANG Zhi-Yong

    2011-01-01

    Difluorooxymethylene-bridged (CF2O) liquid crystal (LC) with low viscosity is prepared and used as a fast response LC material. When the material is mixed with isothiocyanato LCs with high birefringence, the visco-elastic coefficient of the mixture decreases evidently and, accordingly, the response performance increases. While the concentration of CF2O LCs is about 7%, the LC mixture approximately maintains high birefringence and exhibits a fastest response performance that is 14% higher than that of pure isothiocyanato LCs. Therefore, the LC material and mixing method could find useful applications in optical devices.%@@ Difluorooxymethylene-bridged(CF2O)liquid crystal(LC)with low viscosity is prepared and used as a fast response LC material.When the material is mixed with isothiocyanato LCs with high birefringence,the visco-elastic coefficient of the mixture decreases evidently and,accordingly,the response performance increases.While the concentration of CF2O LCs is about 7%,the LC mixture approximately maintains high birefringence and exhibits a fastest response performance that is 14%higher than that of pure isothiocyanato LCs.Therefore,the LC material and mixing method could find useful applications in optical devices.

  1. Colloid-in-liquid crystal gels that respond to biomolecular interactions.

    Science.gov (United States)

    Agarwal, Ankit; Sidiq, Sumyra; Setia, Shilpa; Bukusoglu, Emre; de Pablo, Juan J; Pal, Santanu Kumar; Abbott, Nicholas L

    2013-08-26

    This paper advances the design of stimuli-responsive materials based on colloidal particles dispersed in liquid crystals (LCs). Specifically, thin films of colloid-in-liquid crystal (CLC) gels undergo easily visualized ordering transitions in response to reversible and irreversible (enzymatic) biomolecular interactions occurring at the aqueous interfaces of the gels. In particular, LC ordering transitions can propagate across the entire thickness of the gels. However, confinement of the LC to small domains with lateral sizes of ∼10 μm does change the nature of the anchoring transitions, as compared to films of pure LC, due to the effects of confinement on the elastic energy stored in the LC. The effects of confinement are also observed to cause the response of individual domains of the LC within the CLC gel to vary significantly from one to another, indicating that manipulation of LC domain size and shape can provide the basis of a general and facile method to tune the response of these LC-based physical gels to interfacial phenomena. Overall, the results presented in this paper establish that CLC gels offer a promising approach to the preparation of self-supporting, LC-based stimuli-responsive materials.

  2. Protein Crystallization

    Science.gov (United States)

    Chernov, Alexander A.

    2005-01-01

    Nucleation, growth and perfection of protein crystals will be overviewed along with crystal mechanical properties. The knowledge is based on experiments using optical and force crystals behave similar to inorganic crystals, though with a difference in orders of magnitude in growing parameters. For example, the low incorporation rate of large biomolecules requires up to 100 times larger supersaturation to grow protein, rather than inorganic crystals. Nucleation is often poorly reproducible, partly because of turbulence accompanying the mixing of precipitant with protein solution. Light scattering reveals fluctuations of molecular cluster size, its growth, surface energies and increased clustering as protein ages. Growth most often occurs layer-by-layer resulting in faceted crystals. New molecular layer on crystal face is terminated by a step where molecular incorporation occurs. Quantitative data on the incorporation rate will be discussed. Rounded crystals with molecularly disordered interfaces will be explained. Defects in crystals compromise the x-ray diffraction resolution crucially needed to find the 3D atomic structure of biomolecules. The defects are immobile so that birth defects stay forever. All lattice defects known for inorganics are revealed in protein crystals. Contribution of molecular conformations to lattice disorder is important, but not studied. This contribution may be enhanced by stress field from other defects. Homologous impurities (e.g., dimers, acetylated molecules) are trapped more willingly by a growing crystal than foreign protein impurities. The trapped impurities induce internal stress eliminated in crystals exceeding a critical size (part of mni for ferritin, lysozyme). Lesser impurities are trapped from stagnant, as compared to the flowing, solution. Freezing may induce much more defects unless quickly amorphysizing intracrystalline water.

  3. Alignment of Silicon tracking systems R&D on Semitransparent Microstrip Sensors

    CERN Document Server

    Duarte, Jordi; Gonzalez, Javier; Jaramillo, Richard; Lopez, Amparo; Martinez, Celso; Moya, David; Ruiz, Alberto; Vila, I; Bassignana, D; Cabruja, E; Lozano, M; Pellegrini, G

    2009-01-01

    We summarize the R&D activities on a novel semitransparent microstrip sensor to be used on laser-based alignment systems for silicon trackers. The new sensor is used both for particle tracking and laser detection. The aim of this research line is to increase the optical transmittance (T) of Silicon microstrips detectors to infrared light, introducing minor modifications to the sensor design still suitable for its industrial production. The optical simulations used in the sensor design have been experimentally validated against several patterned material samples. This activities have been carried out in the context of SiLC collaboration for the next International Linear Collider.

  4. Computational crystallization.

    Science.gov (United States)

    Altan, Irem; Charbonneau, Patrick; Snell, Edward H

    2016-07-15

    Crystallization is a key step in macromolecular structure determination by crystallography. While a robust theoretical treatment of the process is available, due to the complexity of the system, the experimental process is still largely one of trial and error. In this article, efforts in the field are discussed together with a theoretical underpinning using a solubility phase diagram. Prior knowledge has been used to develop tools that computationally predict the crystallization outcome and define mutational approaches that enhance the likelihood of crystallization. For the most part these tools are based on binary outcomes (crystal or no crystal), and the full information contained in an assembly of crystallization screening experiments is lost. The potential of this additional information is illustrated by examples where new biological knowledge can be obtained and where a target can be sub-categorized to predict which class of reagents provides the crystallization driving force. Computational analysis of crystallization requires complete and correctly formatted data. While massive crystallization screening efforts are under way, the data available from many of these studies are sparse. The potential for this data and the steps needed to realize this potential are discussed.

  5. Heteroepitaxial formation of aligned mesostructured silica films with large structural periodicities from mixed surfactant systems.

    Science.gov (United States)

    Hayase, Saeko; Kanno, Yosuke; Watanabe, Masatoshi; Takahashi, Masahiko; Kuroda, Kazuyuki; Miyata, Hirokatsu

    2013-06-11

    Liquid-crystal phases consisting of cylindrical micelles of amphiphilic block copolymers and silica precursors are epitaxially built up on aligned surface micelles formed by an alkyl-PEO surfactant, Brij56, irrespective of the large difference in the intrinsic structural periodicities resulting in the formation of fully aligned mesostructured silica films with large lattice constants. Brij56 works as an alignment controlling agent on rubbing-treated polyimide through selective adsorption from a precursor solution containing the two surfactants, a block copolymer and Brij56, through strong hydrophobic interactions to form an anisotropic surface micelle structure. Aligned mesostructured silica layers with larger periodicities, which dominantly consist of block copolymers, form on these aligned surface micelles by gradually changing the vertical periodicity keeping the lateral intermicelle distance constant. This can be regarded as a kind of heteroepitaxy because the lattice constant at the surface is different from that of the bulk of the film. On the basis of this new concept, highly aligned mesostructured silica films with structural periodicities as large as 10 nm are successfully formed, which has never been achieved when the block copolymers are used alone as the structure-directing agent. The periodicity of the aligned films can precisely be controlled by an appropriate choice of block copolymers and the mixing ratio of the two surfactants, which increases the opportunity for applications of these films with highly anisotropic mesoscale structure.

  6. Velocity-aligned Doppler spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z.; Koplitz, B.; Wittig, C.

    1989-03-01

    The technique of velocity-aligned Doppler spectrosocopy (VADS) is presented and discussed. For photolysis/probe experiments with pulsed initiation, VADS can yield Doppler profiles for nascent photofragments that allow detailed center-of-mass (c.m.) kinetic energy distributions to be extracted. When compared with traditional forms of Doppler spectroscopy, the improvement in kinetic energy resolution is dramatic. Changes in the measured profiles are a consequence of spatial discrimination (i.e., focused and overlapping photolysis and probe beams) and delayed observation. These factors result in the selective detection of species whose velocities are aligned with the wave vector of the probe radiation k/sub pr/, thus revealing the speed distribution along k/sub pr/ rather than the distribution of nascent velocity components projected upon this direction. Mathematical details of the procedure used to model VADS are given, and experimental illustrations for HI, H/sub 2/S, and NH/sub 3/ photodissociation are presented. In these examples, pulsed photodissociation produces H atoms that are detected by sequential two-photon, two-frequency ionization via Lyman-..cap alpha.. with a pulsed laser (121.6+364.7 nm), and measuring the Lyman-..cap alpha.. Doppler profile as a function of probe delay reveals both internal and c.m. kinetic energy distributions for the photofragments. Strengths and weaknesses of VADS as a tool for investigating photofragmentation phenomena are also discussed.

  7. Screening antioxidants using LC-MS: case study with cocoa.

    Science.gov (United States)

    Calderón, Angela I; Wright, Brian J; Hurst, W Jeffrey; van Breemen, Richard B

    2009-07-08

    Oxidative stress enhances pathological processes contributing to cancer, cardiovascular disease, and neurodegenerative diseases, and dietary antioxidants may counteract these deleterious processes. Because rapid methods to evaluate and compare food products for antioxidant benefits are needed, a new assay based on liquid chromatography-mass spectrometry (LC-MS) was developed for the identification and quantitative analysis of antioxidants in complex natural product samples such as food extracts. This assay is based on the comparison of electrospray LC-MS profiles of sample extracts before and after treatment with reactive oxygen species such as hydrogen peroxide or 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). Using this assay, methanolic extracts of cocoa powder were analyzed, and procyanidins were found to be the most potent antioxidant species. These species were identified using LC-MS, LC-MS/MS, accurate mass measurement, and comparison with reference standards. Furthermore, LC-MS was used to determine the levels of these species in cocoa samples. Catechin and epicatechin were the most abundant antioxidants followed by their dimers and trimers. The most potent antioxidants in cocoa were trimers and dimers of catechin and epicatechin, such as procyanidin B2, followed by catechin and epicatechin. This new LC-MS assay facilitates the rapid identification and then the determination of the relative antioxidant activities of individual antioxidant species in complex natural product samples and food products such as cocoa.

  8. Double phase conjugation in tungsten bronze crystals.

    Science.gov (United States)

    Sharp, E J; Clark Iii, W W; Miller, M J; Wood, G L; Monson, B; Salamo, G J; Neurgaonkar, R R

    1990-02-20

    In this paper we report a new method for double phase conjugation particularly suited to the tungsten bronze crystal strontium barium niobate. It has also been observed to produce conjugate waves in BaTiO(3) and BSKNN. This new arrangement is called the bridge conjugator because the two beams enter opposing [100] crystal faces and fan together to form a bridge without reflection off a crystal face. Our measurements indicate that the bridge conjugator is competitive with previously reported double phase conjugate mirrors in reflectivity, response time, ease of alignment, and fidelity.

  9. Liquid Crystal Research Shows Deformation By Drying

    Science.gov (United States)

    2003-01-01

    These images, from David Weitz's liquid crystal research, show ordered uniform sized droplets (upper left) before they are dried from their solution. After the droplets are dried (upper right), they are viewed with crossed polarizers that show the deformation caused by drying, a process that orients the bipolar structure of the liquid crystal within the droplets. When an electric field is applied to the dried droplets (lower left), and then increased (lower right), the liquid crystal within the droplets switches its alignment, thereby reducing the amount of light that can be scattered by the droplets when a beam is shone through them.

  10. Alignment of primary Al3Ni phases in hypereutectic Al-Ni alloys with various compositions under high magnetic fields

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Al-Ni hypereutectic alloys with various compositions were solidified under various magnetic field con- ditions to investigate the alignment of primary Al3Ni phases. The results showed that the application of high magnetic fields could improve the homogeneity of the primary Al3Ni phase distribution and induce the alignment of primary Al3Ni phases in the direction perpendicular to the magnetic field direction to form chain-like structures. However, the alignment was different from the orientation of the Al3Ni phases. Furthermore, the degree of the alignment decreased with the increasing concentration of Ni element. This can be attributed to the combination effects of high magnetic field and alloy composition on the concentration field around the crystallized primary Al3Ni crystals.

  11. Alignment of primary Al3Ni phases in hypereutectic AI-Ni alloys with various compositions under high magnetic fields

    Institute of Scientific and Technical Information of China (English)

    WANG Qiang; WANG ZhongYing; LIU Tie; WANG ChunJiang; ZHANG Chao; HE JiCheng

    2009-01-01

    Al-Ni hypereutectic alloys with various compositions were solidified under various magnetic field conditions to investigate the alignment of primary Al3Ni phases. The results showed that the application of high magnetic fields could improve the homogeneity of the primary Al3Ni phase distribution and induce the alignment of primary Al3Ni phases in the direction perpendicular to the magnetic field direction to form chain-like structures. However, the alignment was different from the orientation of the Al3Ni phases. Furthermore, the degree of the alignment decreased with the increasing concentration of Ni element. This can be attributed to the combination effects of high magnetic field and alloy composition on the concentration field around the crystallized primary Al3Ni crystals.

  12. Copper-encapsulated vertically aligned carbon nanotube arrays.

    Science.gov (United States)

    Stano, Kelly L; Chapla, Rachel; Carroll, Murphy; Nowak, Joshua; McCord, Marian; Bradford, Philip D

    2013-11-13

    A new procedure is described for the fabrication of vertically aligned carbon nanotubes (VACNTs) that are decorated, and even completely encapsulated, by a dense network of copper nanoparticles. The process involves the conformal deposition of pyrolytic carbon (Py-C) to stabilize the aligned carbon-nanotube structure during processing. The stabilized arrays are mildly functionalized using oxygen plasma treatment to improve wettability, and they are then infiltrated with an aqueous, supersaturated Cu salt solution. Once dried, the salt forms a stabilizing crystal network throughout the array. After calcination and H2 reduction, Cu nanoparticles are left decorating the CNT surfaces. Studies were carried out to determine the optimal processing parameters to maximize Cu content in the composite. These included the duration of Py-C deposition and system process pressure as well as the implementation of subsequent and multiple Cu salt solution infiltrations. The optimized procedure yielded a nanoscale hybrid material where the anisotropic alignment from the VACNT array was preserved, and the mass of the stabilized arrays was increased by over 24-fold because of the addition of Cu. The procedure has been adapted for other Cu salts and can also be used for other metal salts altogether, including Ni, Co, Fe, and Ag. The resulting composite is ideally suited for application in thermal management devices because of its low density, mechanical integrity, and potentially high thermal conductivity. Additionally, further processing of the material via pressing and sintering can yield consolidated, dense bulk composites.

  13. Self-aligning and compressed autosophy video databases

    Science.gov (United States)

    Holtz, Klaus E.

    1993-04-01

    Autosophy, an emerging new science, explains `self-assembling structures,' such as crystals or living trees, in mathematical terms. This research provides a new mathematical theory of `learning' and a new `information theory' which permits the growing of self-assembling data network in a computer memory similar to the growing of `data crystals' or `data trees' without data processing or programming. Autosophy databases are educated very much like a human child to organize their own internal data storage. Input patterns, such as written questions or images, are converted to points in a mathematical omni dimensional hyperspace. The input patterns are then associated with output patterns, such as written answers or images. Omni dimensional information storage will result in enormous data compression because each pattern fragment is only stored once. Pattern recognition in the text or image files is greatly simplified by the peculiar omni dimensional storage method. Video databases will absorb input images from a TV camera and associate them with textual information. The `black box' operations are totally self-aligning where the input data will determine their own hyperspace storage locations. Self-aligning autosophy databases may lead to a new generation of brain-like devices.

  14. Galaxy alignment on large and small scales

    Science.gov (United States)

    Kang, X.; Lin, W. P.; Dong, X.; Wang, Y. O.; Dutton, A.; Macciò, A.

    2016-10-01

    Galaxies are not randomly distributed across the universe but showing different kinds of alignment on different scales. On small scales satellite galaxies have a tendency to distribute along the major axis of the central galaxy, with dependence on galaxy properties that both red satellites and centrals have stronger alignment than their blue counterparts. On large scales, it is found that the major axes of Luminous Red Galaxies (LRGs) have correlation up to 30Mpc/h. Using hydro-dynamical simulation with star formation, we investigate the origin of galaxy alignment on different scales. It is found that most red satellite galaxies stay in the inner region of dark matter halo inside which the shape of central galaxy is well aligned with the dark matter distribution. Red centrals have stronger alignment than blue ones as they live in massive haloes and the central galaxy-halo alignment increases with halo mass. On large scales, the alignment of LRGs is also from the galaxy-halo shape correlation, but with some extent of mis-alignment. The massive haloes have stronger alignment than haloes in filament which connect massive haloes. This is contrary to the naive expectation that cosmic filament is the cause of halo alignment.

  15. Multiple sequence alignment accuracy and phylogenetic inference.

    Science.gov (United States)

    Ogden, T Heath; Rosenberg, Michael S

    2006-04-01

    Phylogenies are often thought to be more dependent upon the specifics of the sequence alignment rather than on the method of reconstruction. Simulation of sequences containing insertion and deletion events was performed in order to determine the role that alignment accuracy plays during phylogenetic inference. Data sets were simulated for pectinate, balanced, and random tree shapes under different conditions (ultrametric equal branch length, ultrametric random branch length, nonultrametric random branch length). Comparisons between hypothesized alignments and true alignments enabled determination of two measures of alignment accuracy, that of the total data set and that of individual branches. In general, our results indicate that as alignment error increases, topological accuracy decreases. This trend was much more pronounced for data sets derived from more pectinate topologies. In contrast, for balanced, ultrametric, equal branch length tree shapes, alignment inaccuracy had little average effect on tree reconstruction. These conclusions are based on average trends of many analyses under different conditions, and any one specific analysis, independent of the alignment accuracy, may recover very accurate or inaccurate topologies. Maximum likelihood and Bayesian, in general, outperformed neighbor joining and maximum parsimony in terms of tree reconstruction accuracy. Results also indicated that as the length of the branch and of the neighboring branches increase, alignment accuracy decreases, and the length of the neighboring branches is the major factor in topological accuracy. Thus, multiple-sequence alignment can be an important factor in downstream effects on topological reconstruction.

  16. Computer simulation of confined liquid crystal dynamics

    CERN Document Server

    Webster, R E

    2001-01-01

    are performed of the formation of structures in confined smectic systems where layer tilt is induced by an imposed surface pretilt. Results show that bookshelf, chevron and tilled layer structures are observable in a confined Gay-Berne system. The formation and stability of the chevron structure are shown to be influenced by surface slip. Results are presented from a series of simulations undertaken to determine whether dynamic processes observed in device-scale liquid crystal cells confined between aligning substrates can be simulated in a molecular system using parallel molecular dynamics of the Gay-Berne model. In a nematic cell, on removal of an aligning field, initial near-surface director relaxation can induce flow, termed 'backflow' in the liquid. This, in turn, can cause director rotation, termed 'orientational kickback', in the centre of the cell. Simulations are performed of the relaxation in nematic systems confined between substrates with a common alignment on removal of an aligning field. Results...

  17. LC-MS quantification of protein drugs: validating protein LC-MS methods with predigestion immunocapture.

    Science.gov (United States)

    Duggan, Jeffrey; Ren, Bailuo; Mao, Yan; Chen, Lin-Zhi; Philip, Elsy

    2016-09-01

    A refinement of protein LC-MS bioanalysis is to use predigestion immunoaffinity capture to extract the drug from matrix prior to digestion. Because of their increased sensitivity, such hybrid assays have been successfully validated and applied to a number of clinical studies; however, they can also be subject to potential interferences from antidrug antibodies, circulating ligands or other matrix components specific to patient populations and/or dosed subjects. The purpose of this paper is to describe validation experiments that measure immunocapture efficiency, digestion efficiency, matrix effect and selectivity/specificity that can be used during method optimization and validation to test the resistance of the method to these potential interferences. The designs and benefits of these experiments are discussed in this report using an actual assay case study.

  18. Crystal Data

    Science.gov (United States)

    SRD 3 NIST Crystal Data (PC database for purchase)   NIST Crystal Data contains chemical, physical, and crystallographic information useful to characterize more than 237,671 inorganic and organic crystalline materials. The data include the standard cell parameters, cell volume, space group number and symbol, calculated density, chemical formula, chemical name, and classification by chemical type.

  19. Galaxy alignments: Observations and impact on cosmology

    CERN Document Server

    Kirk, Donnacha; Hoekstra, Henk; Joachimi, Benjamin; Kitching, Thomas D; Mandelbaum, Rachel; Sifón, Cristóbal; Cacciato, Marcello; Choi, Ami; Kiessling, Alina; Leonard, Adrienne; Rassat, Anais; Schäfer, Björn Malte

    2015-01-01

    Galaxy shapes are not randomly oriented, rather they are statistically aligned in a way that can depend on formation environment, history and galaxy type. Studying the alignment of galaxies can therefore deliver important information about the astrophysics of galaxy formation and evolution as well as the growth of structure in the Universe. In this review paper we summarise key measurements of intrinsic alignments, divided by galaxy type, scale and environment. We also cover the statistics and formalism necessary to understand the observations in the literature. With the emergence of weak gravitational lensing as a precision probe of cosmology, galaxy alignments took on an added importance because they can mimic cosmic shear, the effect of gravitational lensing by large-scale structure on observed galaxy shapes. This makes intrinsic alignments an important systematic effect in weak lensing studies. We quantify the impact of intrinsic alignments on cosmic shear surveys and finish by reviewing practical mitigat...

  20. Magnetic alignment and patterning of cellulose fibers

    Directory of Open Access Journals (Sweden)

    Fumiko Kimura and Tsunehisa Kimura

    2008-01-01

    Full Text Available The alignment and patterning of cellulose fibers under magnetic fields are reported. Static and rotating magnetic fields were used to align cellulose fibers with sizes ranging from millimeter to nanometer sizes. Cellulose fibers of the millimeter order, which were prepared for papermaking, and much smaller fibers with micrometer to nanometer sizes prepared by the acid hydrolysis of larger ones underwent magnetic alignment. Under a rotating field, a uniaxial alignment of fibers was achieved. The alignment was successfully fixed by the photopolymerization of a UV-curable resin precursor used as matrix. A monodomain chiral nematic film was prepared from an aqueous suspension of nanofibers. Using a field modulator inserted in a homogeneous magnetic field, simultaneous alignment and patterning were achieved

  1. Magnetic alignment and patterning of cellulose fibers

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Fumiko; Kimura, Tsunehisa [Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)], E-mail: tkimura@kais.kyoto-u.ac.jp

    2008-04-01

    The alignment and patterning of cellulose fibers under magnetic fields are reported. Static and rotating magnetic fields were used to align cellulose fibers with sizes ranging from millimeter to nanometer sizes. Cellulose fibers of the millimeter order, which were prepared for papermaking, and much smaller fibers with micrometer to nanometer sizes prepared by the acid hydrolysis of larger ones underwent magnetic alignment. Under a rotating field, a uniaxial alignment of fibers was achieved. The alignment was successfully fixed by the photopolymerization of a UV-curable resin precursor used as matrix. A monodomain chiral nematic film was prepared from an aqueous suspension of nanofibers. Using a field modulator inserted in a homogeneous magnetic field, simultaneous alignment and patterning were achieved.

  2. Liquid crystal microlens with tunable-focus over focal plane driven by low-voltage signal

    Science.gov (United States)

    Kang, Shengwu; Rong, Xing; Zhang, Xinyu; Xie, Changsheng; Zhang, Tianxu

    2012-11-01

    A liquid crystal (LC) microlens with a new type of electrode pattern is designed. The both bottom and top ITO electrodes of LC microlens are placed face to face, and are separated by glass spacer with the thickness in micron scale, and then LC materials are injected into the cell constructed by them. Because of the two electrodes directly and closely facing the LC layer injected, the design can largely decrease the driving signal voltage for LC lens. The bottom electrode is designed with one round hole pattern. The top electrode is four circle patterns. The diameters of round hole and circle are 500μm and 160μm, respectively. Each circle pattern electrode can be used to focus incident light into different region over the focal plane of LC lens. When the four circle electrodes are driven by different signal at the same time, the focus can be moved off-axis over the focal plane of LC lens, and thus the voltage amplitude can be varied in the range from 0Vrms to 20Vrms. So, we realize a LC microlens with tunable-focus over the focal plane of LC lens driven by low-amplitude voltage signal.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-08-18

    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.

  4. Velocity-aligned Doppler spectroscopy

    Science.gov (United States)

    Xu, Z.; Koplitz, B.; Wittig, C.

    1989-03-01

    The use of velocity-aligned Doppler spectroscopy (VADS) to measure center-of-mass kinetic-energy distributions of nascent photofragments produced in pulsed-initiation photolysis/probe experiments is described and demonstrated. In VADS, pulsed photolysis and probe laser beams counterpropagate through the ionization region of a time-of-flight mass spectrometer. The theoretical principles of VADS and the mathematical interpretation of VADS data are explained and illustrated with diagrams; the experimental setup is described; and results for the photodissociation of HI, H2S, and NH3 are presented in graphs and characterized in detail. VADS is shown to give much higher kinetic-energy resolution than conventional Doppler spectroscopy.

  5. Microwave Emission from Aligned Dust

    CERN Document Server

    Lazarian, A

    2003-01-01

    Polarized microwave emission from dust is an important foreground that may contaminate polarized CMB studies unless carefully accounted for. We discuss potential difficulties associated with this foreground, namely, the existence of different grain populations with very different emission/polarization properties and variations of the polarization yield with grain temperature. In particular, we discuss observational evidence in favor of rotational emission from tiny PAH particles with dipole moments, i.e. ``spinning dust'', and also consider magneto-dipole emission from strongly magnetized grains. We argue that in terms of polarization, the magneto-dipole emission may dominate even if its contribution to total emissivity is subdominant. Addressing polarized emission at frequencies larger than approsimately 100 GHz, we discuss the complications arising from the existence of dust components with different temperatures and possibly different alignment properties.

  6. Recursions for statistical multiple alignment.

    Science.gov (United States)

    Hein, Jotun; Jensen, Jens Ledet; Pedersen, Christian N S

    2003-12-09

    Algorithms are presented that allow the calculation of the probability of a set of sequences related by a binary tree that have evolved according to the Thorne-Kishino-Felsenstein model for a fixed set of parameters. The algorithms are based on a Markov chain generating sequences and their alignment at nodes in a tree. Depending on whether the complete realization of this Markov chain is decomposed into the first transition and the rest of the realization or the last transition and the first part of the realization, two kinds of recursions are obtained that are computationally similar but probabilistically different. The running time of the algorithms is O(Pi id=1 Li), where Li is the length of the ith observed sequences and d is the number of sequences. An alternative recursion is also formulated that uses only a Markov chain involving the inner nodes of a tree.

  7. Aligned carbon nanotubes for nanoelectronics

    Science.gov (United States)

    Choi, Won Bong; Bae, Eunju; Kang, Donghun; Chae, Soodoo; Cheong, Byung-ho; Ko, Ju-hye; Lee, Eungmin; Park, Wanjun

    2004-10-01

    We discuss the central issues to be addressed for realizing carbon nanotube (CNT) nanoelectronics. We focus on selective growth, electron energy bandgap engineering and device integration. We have introduced a nanotemplate to control the selective growth, length and diameter of CNTs. Vertically aligned CNTs are synthesized for developing a vertical CNT-field effect transistor (FET). The ohmic contact of the CNT/metal interface is formed by rapid thermal annealing. Diameter control, synthesis of Y-shaped CNTs and surface modification of CNTs open up the possibility for energy bandgap modulation. The concepts of an ultra-high density transistor based on the vertical-CNT array and a nonvolatile memory based on the top gate structure with an oxide-nitride-oxide charge trap are also presented. We suggest that the deposited memory film can be used for the quantum dot storage due to the localized electric field created by a nano scale CNT-electron channel.

  8. Multilingual alignments by monolingual string differences

    OpenAIRE

    Lardilleux, Adrien; Lepage, Yves

    2008-01-01

    International audience; We propose a method to obtain subsentential alignments from several languages simultaneously. The method handles several languages at once, and avoids the complexity explosion due to the usual pair-by-pair processing. It can be used for different units (characters, morphemes, words, chunks). An evaluation of word alignments with a trilingual machine translation corpus has been conducted. A comparison of the results with those obtained by state of the art alignment soft...

  9. Distributed Interference Alignment with Low Overhead

    CERN Document Server

    Ma, Yanjun; Chen, Rui

    2011-01-01

    Based on closed-form interference alignment (IA) solutions, a low overhead distributed interference alignment (LOIA) scheme is proposed in this paper for the $K$-user SISO interference channel, and extension to multiple antenna scenario is also considered. Compared with the iterative interference alignment (IIA) algorithm proposed by Gomadam et al., the overhead is greatly reduced. Simulation results show that the IIA algorithm is strictly suboptimal compared with our LOIA algorithm in the overhead-limited scenario.

  10. Spin alignment in superdeformed rotational bands

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, F.S. (Lawrence Berkeley Lab., CA (USA). Nuclear Science Div.)

    1990-12-24

    Many superdeformed bands in different nuclei are found to have virtually identical moments of inertia and alignments that differ from each other by quantized amounts - multiples of 1/2 {Dirac h}. Pseudo spins represent the only source of quantized alignment that has been thought of to date. Additional puzzles in these bands are the absence of other larger effects on the moments of inertia, and a surprising number of alignments of 1 {Dirac h}. (orig.).

  11. COS to FGS Alignment {NUV}

    Science.gov (United States)

    Hartig, George

    2009-07-01

    DESCRIPTION: In order to determine the location of the COS reference frame with respect to the FGS reference frames, NUV MIRRORA images will be obtained of an astrometric target and field. Astrometric guide stars and targets must be employed for this activity in order to facilitate the alignment wth the FGS. Images will be obtained at the initial pointing and at positions offset in V2 and in V3. Starting with the original blind pointing, obtain MIRRORA image exposures in a 5x5 POS-TARG grid centered on initial pointing; repeat the image sequence at two bracketing focus positions in same visit. Following completion of third pattern, return to nominal focus and perform 5x5 ACQ/SEARCH target acquisition and obtain one TIME-TAG MIRRORA image and one ACCUM verification exposure. Next perform an ACQ/IMAGE target acquisition followed by an ACCUM verification exposure. Also obtain ACCUM verification exposure for each of the two alternate focus positions used previously. Using MIRRORB obtain ACCUM confirmation image at nominal focus and ACCUM images at alternate focus positions and then perform an ACQ/IMAGE and confirming image at nominal focus. Analyze imagery, uplink pointing offset as offset 11469A and adjust nominal focus via patchable constant uplinked with subsequent visit of this program; update aperture locations via modified SIAF file uplinked with subsequent SMS. Use updated focus and offset pointing as input for COS 09 {program 11469 - NUV Optics Alignment and Focus} {note the SIAF update is not a prerequisite for COS 09 to proceed, but the pointing offset and focus update are}.

  12. Localised polymer networks in chiral nematic liquid crystals for high speed photonic switching

    Energy Technology Data Exchange (ETDEWEB)

    Tartan, Chloe C., E-mail: chloe.tartan@eng.ox.ac.uk, E-mail: steve.elston@eng.ox.ac.uk; Salter, Patrick S.; Booth, Martin J.; Morris, Stephen M.; Elston, Steve J., E-mail: chloe.tartan@eng.ox.ac.uk, E-mail: steve.elston@eng.ox.ac.uk [Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ (United Kingdom)

    2016-05-14

    Self-assembled periodic structures based upon chiral liquid crystalline materials have significant potential in the field of photonics ranging from fast-switching optoelectronic devices to low-threshold lasers. The flexoelectro-optic effect, which is observed in chiral nematic liquid crystals (LCs) when an electric field is applied perpendicular to the helical axis, has significant potential as it exhibits analogue switching in 10–100 μs. However, the major technological barrier that prohibits the commercial realisation of this electro-optic effect is the requirement of a uniform, in-plane alignment of the helix axis between glass substrates. Here, it is shown that periodic polymer structures engineered in the nematic phase of a chiral nematic LC device using direct laser writing can result in the spontaneous formation of the necessary uniform lying helix (ULH) state. Specifically, two-photon polymerization is used in conjunction with a spatial light modulator so as to correct for aberrations introduced by the bounding glass substrates enabling the polymer structures to be fabricated directly into the device. The ULH state appears to be stable in the absence of an externally applied electric field, and the optimum contrast between the bright and dark states is obtained using polymer structures that have periodicities of the order of the device thickness.

  13. Localised polymer networks in chiral nematic liquid crystals for high speed photonic switching

    Science.gov (United States)

    Tartan, Chloe C.; Salter, Patrick S.; Booth, Martin J.; Morris, Stephen M.; Elston, Steve J.

    2016-05-01

    Self-assembled periodic structures based upon chiral liquid crystalline materials have significant potential in the field of photonics ranging from fast-switching optoelectronic devices to low-threshold lasers. The flexoelectro-optic effect, which is observed in chiral nematic liquid crystals (LCs) when an electric field is applied perpendicular to the helical axis, has significant potential as it exhibits analogue switching in 10-100 μs. However, the major technological barrier that prohibits the commercial realisation of this electro-optic effect is the requirement of a uniform, in-plane alignment of the helix axis between glass substrates. Here, it is shown that periodic polymer structures engineered in the nematic phase of a chiral nematic LC device using direct laser writing can result in the spontaneous formation of the necessary uniform lying helix (ULH) state. Specifically, two-photon polymerization is used in conjunction with a spatial light modulator so as to correct for aberrations introduced by the bounding glass substrates enabling the polymer structures to be fabricated directly into the device. The ULH state appears to be stable in the absence of an externally applied electric field, and the optimum contrast between the bright and dark states is obtained using polymer structures that have periodicities of the order of the device thickness.

  14. The art of editing RNA structural alignments

    DEFF Research Database (Denmark)

    Andersen, Ebbe Sloth

    2014-01-01

    Manual editing of RNA structural alignments may be considered more art than science, since it still requires an expert biologist to take multiple levels of information into account and be slightly creative when constructing high-quality alignments. Even though the task is rather tedious, it is re......Manual editing of RNA structural alignments may be considered more art than science, since it still requires an expert biologist to take multiple levels of information into account and be slightly creative when constructing high-quality alignments. Even though the task is rather tedious...

  15. The art of editing RNA structural alignments

    DEFF Research Database (Denmark)

    Andersen, Ebbe Sloth

    2014-01-01

    Manual editing of RNA structural alignments may be considered more art than science, since it still requires an expert biologist to take multiple levels of information into account and be slightly creative when constructing high-quality alignments. Even though the task is rather tedious, it is re......Manual editing of RNA structural alignments may be considered more art than science, since it still requires an expert biologist to take multiple levels of information into account and be slightly creative when constructing high-quality alignments. Even though the task is rather tedious...

  16. The alignment between spatial planning, transportation planning ...

    African Journals Online (AJOL)

    engagement processes, support, ... Carel Schoeman • The alignment between spatial planning, transportation planning and environmental ..... NDOT: Public Transport Strategy (2007) .... Community Land Reform Act 28 of 1996 (CLARA).

  17. Nova alignment and laser diagnostics systems - 1

    Energy Technology Data Exchange (ETDEWEB)

    Bliss, E.S.; Ozarski, R.G.; Myers, D.W.; Richards, J.B.; Swift, C.D.; Boyd, R.D.; Hugenberger, R.E.; Seppala, L.G.; Parker, J.; Dryden, E.H.

    1981-01-01

    The alignment and laser diagnostic systems guide laser pulses through the separate amplifier chains to the target, measure their temporal, spatial and energy characteristics, and ensure simultaneous arrival at the target to within 5 picoseconds. Alignment tasks accomplished prior to each target shot involve automatic or remote-manual adjustments of approximately 2000 stepper motors and other actuators for the full 20 beam, 3 wavelength system. The primary detectors for alignment functions are CCD cameras with both digital and standard video output. Diagnostic data handling and processing is accomplished digitally, and both the alignment and diagnostic systems are integrated into the facility-wide digital control network.

  18. VIRUS spectrograph assembly and alignment procedures

    Science.gov (United States)

    Prochaska, Travis; Allen, Richard D.; Boster, Emily; DePoy, D. L.; Herbig, Benjamin; Hill, Gary J.; Lee, Hanshin; Marshall, Jennifer L.; Martin, Emily C.; Meador, William; Rheault, Jean-Philippe; Tuttle, Sarah E.; Vattiat, Brian L.

    2012-09-01

    We describe the mechanical assembly and optical alignment processes used to construct the Visual Integral-Field Replicable Unit Spectrograph (VIRUS) instrument. VIRUS is a set of 150+ optical spectrographs designed to support observations for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). To meet the instrument's manufacturing constraints, a production line will be set up to build subassemblies in parallel. To aid in the instrument's assembly and alignment, specialized fixtures and adjustment apparatuses have been developed. We describe the design and operations of the various optics alignment apparatuses, as well as the mirrors' alignment and bonding fixtures.

  19. The twilight zone of cis element alignments.

    Science.gov (United States)

    Sebastian, Alvaro; Contreras-Moreira, Bruno

    2013-02-01

    Sequence alignment of proteins and nucleic acids is a routine task in bioinformatics. Although the comparison of complete peptides, genes or genomes can be undertaken with a great variety of tools, the alignment of short DNA sequences and motifs entails pitfalls that have not been fully addressed yet. Here we confront the structural superposition of transcription factors with the sequence alignment of their recognized cis elements. Our goals are (i) to test TFcompare (http://floresta.eead.csic.es/tfcompare), a structural alignment method for protein-DNA complexes; (ii) to benchmark the pairwise alignment of regulatory elements; (iii) to define the confidence limits and the twilight zone of such alignments and (iv) to evaluate the relevance of these thresholds with elements obtained experimentally. We find that the structure of cis elements and protein-DNA interfaces is significantly more conserved than their sequence and measures how this correlates with alignment errors when only sequence information is considered. Our results confirm that DNA motifs in the form of matrices produce better alignments than individual sequences. Finally, we report that empirical and theoretically derived twilight thresholds are useful for estimating the natural plasticity of regulatory sequences, and hence for filtering out unreliable alignments.

  20. Some aspects of SR beamline alignment

    Energy Technology Data Exchange (ETDEWEB)

    Gaponov, Yu.A., E-mail: Yury.Gaponov@maxlab.lu.se [MAX-lab, Lund University, P.O.B. 118, SE-221 00 Lund (Sweden); Cerenius, Y. [MAX-lab, Lund University, P.O.B. 118, SE-221 00 Lund (Sweden); Nygaard, J. [Faculty of Life Sciences, University of Copenhagen, DK-1871 Frederiksberg C (Denmark); Ursby, T.; Larsson, K. [MAX-lab, Lund University, P.O.B. 118, SE-221 00 Lund (Sweden)

    2011-09-01

    Based on the Synchrotron Radiation (SR) beamline optical element-by-element alignment with analysis of the alignment results an optimized beamline alignment algorithm has been designed and developed. The alignment procedures have been designed and developed for the MAX-lab I911-4 fixed energy beamline. It has been shown that the intermediate information received during the monochromator alignment stage can be used for the correction of both monochromator and mirror without the next stages of alignment of mirror, slits, sample holder, etc. Such an optimization of the beamline alignment procedures decreases the time necessary for the alignment and becomes useful and helpful in the case of any instability of the beamline optical elements, storage ring electron orbit or the wiggler insertion device, which could result in the instability of angular and positional parameters of the SR beam. A general purpose software package for manual, semi-automatic and automatic SR beamline alignment has been designed and developed using the developed algorithm. The TANGO control system is used as the middle-ware between the stand-alone beamline control applications BLTools, BPMonitor and the beamline equipment.

  1. Effect of alignment angle on the alignment accuracy of a miniature rotation robot for microscopy imaging

    Directory of Open Access Journals (Sweden)

    Wenfeng Wan

    2017-05-01

    Full Text Available Most recently, a miniature rotation robot has been proposed to allow imaging samples from multidirection for the first time. However, one existing problem for that rotation robot is that the alignment efficiency and accuracy is affected greatly by the alignment angle. This article investigates the effect of alignment angle on the alignment accuracy. Alignment accuracy is measured by sample’s position shift during a 360° rotation. Firstly, the miniature robotic system and its alignment principle are introduced briefly. Then, the source of alignment error is analyzed and the error model is built. After that, simulation results are given and indicate that as alignment angle increases, alignment error first decreases, then becomes stable and finally increases. Reasons for the trend of alignment error are explained. Finally, experiment results are demonstrated and have a good agreement with theoretical analysis and simulation results. The results indicate that 90° should be chosen as the alignment angle to ensure both alignment accuracy and alignment speed.

  2. The effects of alignment error and alignment filtering on the sitewise detection of positive selection.

    Science.gov (United States)

    Jordan, Gregory; Goldman, Nick

    2012-04-01

    When detecting positive selection in proteins, the prevalence of errors resulting from misalignment and the ability of alignment filters to mitigate such errors are not well understood, but filters are commonly applied to try to avoid false positive results. Focusing on the sitewise detection of positive selection across a wide range of divergence levels and indel rates, we performed simulation experiments to quantify the false positives and false negatives introduced by alignment error and the ability of alignment filters to improve performance. We found that some aligners led to many false positives, whereas others resulted in very few. False negatives were a problem for all aligners, increasing with sequence divergence. Of the aligners tested, PRANK's codon-based alignments consistently performed the best and ClustalW performed the worst. Of the filters tested, GUIDANCE performed the best and Gblocks performed the worst. Although some filters showed good ability to reduce the error rates from ClustalW and MAFFT alignments, none were found to substantially improve the performance of PRANK alignments under most conditions. Our results revealed distinct trends in error rates and power levels for aligners and filters within a biologically plausible parameter space. With the best aligner, a low false positive rate was maintained even with extremely divergent indel-prone sequences. Controls using the true alignment and an optimal filtering method suggested that performance improvements could be gained by improving aligners or filters to reduce the prevalence of false negatives, especially at higher divergence levels and indel rates.

  3. Triangular Alignment (TAME). A Tensor-based Approach for Higher-order Network Alignment

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Shahin [Purdue Univ., West Lafayette, IN (United States); Gleich, David F. [Purdue Univ., West Lafayette, IN (United States); Kolda, Tamara G. [Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Grama, Ananth [Purdue Univ., West Lafayette, IN (United States)

    2015-11-01

    Network alignment is an important tool with extensive applications in comparative interactomics. Traditional approaches aim to simultaneously maximize the number of conserved edges and the underlying similarity of aligned entities. We propose a novel formulation of the network alignment problem that extends topological similarity to higher-order structures and provide a new objective function that maximizes the number of aligned substructures. This objective function corresponds to an integer programming problem, which is NP-hard. Consequently, we approximate this objective function as a surrogate function whose maximization results in a tensor eigenvalue problem. Based on this formulation, we present an algorithm called Triangular AlignMEnt (TAME), which attempts to maximize the number of aligned triangles across networks. We focus on alignment of triangles because of their enrichment in complex networks; however, our formulation and resulting algorithms can be applied to general motifs. Using a case study on the NAPABench dataset, we show that TAME is capable of producing alignments with up to 99% accuracy in terms of aligned nodes. We further evaluate our method by aligning yeast and human interactomes. Our results indicate that TAME outperforms the state-of-art alignment methods both in terms of biological and topological quality of the alignments.

  4. 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

  5. Macromolecular crystallization and crystal perfection

    CERN Document Server

    Chayen, Naomi E; Snell, Edward H

    2010-01-01

    Structural biology is key to our understanding of the mechanisms of biological processes. This text describes current methods and future frontiers in crystal growth and use of X-ray and neutron crystallography, in the context of automation of crystallization and generation of synchrotron X-ray and neutron beams.

  6. A Star-shaped Oligo(phenylenevinylene) Liquid Crystal Host with an Anthracene Guest-A Double Nanosegregating Supermesogen.

    Science.gov (United States)

    Maier, Philipp; Grüne, Matthias; Lehmann, Matthias

    2017-01-23

    Hexasubstituted C3 -symmetric benzenes with three elongated shape-persistent oligo(phenylenevinylene) arms and three pyridyl hydrogen-bond acceptors have been synthesized. These mesogens assemble in a double-helical columnar liquid crystal (LC) structure, owing to the compensation of free spaces between conjugated arms by dimer formation. The void is filled also by up to three anthracene carboxylic acids as guests forming hydrogen bonded supermesogens assembling in columnar LC and soft-crystal phases. Thin film fluorescence and solid-state NMR spectroscopy imply a transition from a disordered columnar LC to an unexpected double nanosegregated morphology of a filled soft columnar crystal phase. An additional intracolumnar separation of anthracene and oligo(phenylenevinylene) chromophores occurs, separate to the general segregation of aliphatic and aromatic building blocks in LC structures. The new type of supermesogens will enable the rational design of host-guest double cables with a wide range of different conjugated building blocks.

  7. Liquid crystal tunable photonic crystal dye laser

    DEFF Research Database (Denmark)

    Buss, Thomas; Christiansen, Mads Brøkner; Smith, Cameron

    2010-01-01

    We present a dye-doped liquid crystal laser using a photonic crystal cavity. An applied electric field to the liquid crystal provides wavelength tunability. The photonic crystal enhances resonant interaction with the gain medium....

  8. Temperature-induced tuning of emission spectra of liquid-crystal optical microcavities

    Science.gov (United States)

    Zemánek, Pavel; Pilát, Zdeněk.; Ježek, Jan; Bernatová, Silvie; Aas, Mehdi; Kiraz, Alper; Jonáš, Alexandr

    2016-12-01

    Emulsion droplets of liquid crystals (LC) suspended in water and labeled with a suitable fluorescent dye can serve as active optofluidic microcavities, since the contrast of refractive index between the LC droplets and the surrounding aqueous medium allows excitation of whispering gallery modes (WGMs) in the droplets. In addition, such emulsion droplets can be also stably trapped in three-dimensions using optical tweezers which stabilizes the droplets while investigating their spectral characteristics. We explore various combinations of fluorescently dyed LC droplets and host liquid - surfactant systems and show that the WGM emission spectrum of an optically trapped LC droplet-based cavity can be largely and (almost) reversibly tuned by controlled changes of the ambient temperature that induce phase transitions in the LC droplets. Our results indicate feasibility of this approach for creating miniature tunable sources of coherent light.

  9. Fiber-optic temperature sensor using a liquid crystal film for laser-induced interstitial thermotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bong-Soo; Tack, Gye-Rae; Chung, Soon-Cheol; Yi, Jeong-Han [Konkuk University, Chungju (Korea, Republic of); Kim, Sin [Cheju National University, Cheju (Korea, Republic of); Cho, Hyo-Sung [Yonsei University, Wonju (Korea, Republic of)

    2005-06-15

    In this paper, we describe the feasibility of developing a new fiber-optic temperature sensor using a thermo-sensitive liquid crystal (LC) film for laser-induced interstitial thermotherapy (LITT). The temperature change in the tissue or the tumor causes the color of the LC film in contacted with the tissue to change, and that change alters the reflectivity of the LC film. The light with a selected wavelength that is transmitted to the LC film and the optical power of the reflected light are measured using transmitting and receiving optical fibers, respectively. Also, the relationship between the temperature and the optical power of reflected light is determined using the characteristics of the LC films.

  10. Centroid stabilization for laser alignment to corner cubes: designing a matched filter

    Energy Technology Data Exchange (ETDEWEB)

    Awwal, Abdul A. S.; Bliss, Erlan; Brunton, Gordon; Kamm, Victoria Miller; Leach, Richard R.; Lowe-Webb, Roger; Roberts, Randy; Wilhelmsen, Karl

    2016-11-08

    Automation of image-based alignment of National Ignition Facility high energy laser beams is providing the capability of executing multiple target shots per day. One important alignment is beam centration through the second and third harmonic generating crystals in the final optics assembly (FOA), which employs two retroreflecting corner cubes as centering references for each beam. Beam-to-beam variations and systematic beam changes over time in the FOA corner cube images can lead to a reduction in accuracy as well as increased convergence durations for the template-based position detector. A systematic approach is described that maintains FOA corner cube templates and guarantees stable position estimation.

  11. Crystal Dislocations

    Directory of Open Access Journals (Sweden)

    Ronald W. Armstrong

    2016-01-01

    Full Text Available Crystal dislocations were invisible until the mid-20th century although their presence had been inferred; the atomic and molecular scale dimensions had prevented earlier discovery. Now they are normally known to be just about everywhere, for example, in the softest molecularly-bonded crystals as well as within the hardest covalently-bonded diamonds. The advent of advanced techniques of atomic-scale probing has facilitated modern observations of dislocations in every crystal structure-type, particularly by X-ray diffraction topography and transmission electron microscopy. The present Special Issue provides a flavor of their ubiquitous presences, their characterizations and, especially, their influence on mechanical and electrical properties.

  12. Bayesian coestimation of phylogeny and sequence alignment

    Directory of Open Access Journals (Sweden)

    Jensen Jens

    2005-04-01

    Full Text Available Abstract Background Two central problems in computational biology are the determination of the alignment and phylogeny of a set of biological sequences. The traditional approach to this problem is to first build a multiple alignment of these sequences, followed by a phylogenetic reconstruction step based on this multiple alignment. However, alignment and phylogenetic inference are fundamentally interdependent, and ignoring this fact leads to biased and overconfident estimations. Whether the main interest be in sequence alignment or phylogeny, a major goal of computational biology is the co-estimation of both. Results We developed a fully Bayesian Markov chain Monte Carlo method for coestimating phylogeny and sequence alignment, under the Thorne-Kishino-Felsenstein model of substitution and single nucleotide insertion-deletion (indel events. In our earlier work, we introduced a novel and efficient algorithm, termed the "indel peeling algorithm", which includes indels as phylogenetically informative evolutionary events, and resembles Felsenstein's peeling algorithm for substitutions on a phylogenetic tree. For a fixed alignment, our extension analytically integrates out both substitution and indel events within a proper statistical model, without the need for data augmentation at internal tree nodes, allowing for efficient sampling of tree topologies and edge lengths. To additionally sample multiple alignments, we here introduce an efficient partial Metropolized independence sampler for alignments, and combine these two algorithms into a fully Bayesian co-estimation procedure for the alignment and phylogeny problem. Our approach results in estimates for the posterior distribution of evolutionary rate parameters, for the maximum a-posteriori (MAP phylogenetic tree, and for the posterior decoding alignment. Estimates for the evolutionary tree and multiple alignment are augmented with confidence estimates for each node height and alignment column

  13. Quantitative regulation of bone-mimetic, oriented collagen/apatite matrix structure depends on the degree of osteoblast alignment on oriented collagen substrates.

    Science.gov (United States)

    Matsugaki, Aira; Isobe, Yoshihiro; Saku, Taro; Nakano, Takayoshi

    2015-02-01

    Bone tissue has a specific anisotropic morphology derived from collagen fiber alignment and the related apatite crystal orientation as a bone quality index. However, the precise mechanism of cellular regulation of the crystallographic orientation of apatite has not been clarified. In this study, anisotropic construction of cell-produced mineralized matrix in vitro was established by initiating organized cellular alignment and subsequent oriented bone-like matrix (collagen/apatite) production. The oriented collagen substrates with three anisotropic levels were prepared by a hydrodynamic method. Primary osteoblasts were cultured on the fabricated substrates until mineralized matrix formation is confirmed. Osteoblast alignment was successfully regulated by the level of substrate collagen orientation, with preferential alignment along the direction of the collagen fibers. Notably, both fibrous orientation of newly synthesized collagen matrix and c-axis of produced apatite crystals showed preferential orientation along the cell direction. Because the degree of anisotropy of the deposited apatite crystals showed dependency on the directional distribution of osteoblasts cultured on the oriented collagen substrates, the cell orientation determines the crystallographic anisotropy of produced apatite crystals. To the best of our knowledge, this is the first report demonstrating that bone tissue anisotropy, even the alignment of apatite crystals, is controllable by varying the degree of osteoblast alignment via regulating the level of substrate orientation.

  14. Smectic Layer Deformation of Ferroelectric Liquid Crystal Sandwiched between Polymer Walls with Anchoring Effects

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Ikehata, Seiichiro; Sato, Fumio

    2002-05-01

    We studied smectic layer structures of ferroelectric liquid crystal (FLC) formed in elongated small spaces surrounded by molecule-aligned polymer walls and rubbed polyimide alignment layers. The polymer walls, which are parallel to the rubbing direction and vertical to the alignment layers, were formed by the photopolymerization of an aligned monomer under patterned ultraviolet light irradiation. From the observation of the alignment textures of the FLC between the polymer walls with a polarizing microscope, it was found that the smectic layer structure was changed from vertical plane bending alignment (chevron structure), as observed with a conventional surface-stabilized FLC, into horizontal plane bending, as the interval between the polymer walls decreased. It is thought that the smectic layer structure is governed by the competition between the anchoring effects of the alignment polyimide layers and the molecule-aligned polymer walls.

  15. AlignHUSH: Alignment of HMMs using structure and hydrophobicity information

    OpenAIRE

    Krishnadev Oruganty; Srinivasan Narayanaswamy

    2011-01-01

    Abstract Background Sensitive remote homology detection and accurate alignments especially in the midnight zone of sequence similarity are needed for better function annotation and structural modeling of proteins. An algorithm, AlignHUSH for HMM-HMM alignment has been developed which is capable of recognizing distantly related domain families The method uses structural information, in the form of predicted secondary structure probabilities, and hydrophobicity of amino acids to align HMMs of t...

  16. Aligned Solidification Structure of the MnBi Phase in Semisolidified Bi-Mn Alloy with a Static Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    Zhongming REN; Hui WANG; Kang DENG; Kuangdi XU

    2004-01-01

    The solidification structure of Bi-3 wt pct Mn alloy grown up in the semisolid zone under the influence of a static magnetic field (up to 1.0 T) and the relation of the magnetic property with the solidification structure have been investigated experimentally. It was shown that the primary phase MnBi crystals in the alloy aligned and oriented along the direction of the applied magnetic field. The orientating tendency and the average length of the elongated MnBi crystals increased with the increase of the applied field and the solidification time. Moreover, the remanence of the alloy along the aligned direction of the MnBi phase in the case of solidification with a magnetic field was apparently anisotropic and nearly double of that without the magnetic field. This indicated that the MnBi crystals oriented and aligned along their easy magnetization axis. A model was proposed to explain the alignment and orientation growth of the MnBi crystals in a magnetic field in terms of the magnetic anisotropy of the crystals and the magnetic interaction between them.

  17. Structural Transitions in Cholesteric Liquid Crystal Droplets

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Ye; Bukusoglu, Emre; Martinez-Gonzalez, Jose A.; Rahimi, Mohammad; Roberts, Tyler F.; Zhang, Rui; Wang, Xiaoguang; Abbott, Nicholas L.; de Pablo, Juan J.

    2016-07-01

    Confinement of cholesteric liquid crystals (ChLC) into droplets leads to a delicate interplay between elasticity, chirality, and surface energy. In this work, we rely on a combination of theory and experiments to understand the rich morphological behavior that arises from that balance. More specifically, a systematic study of micrometer-sized ChLC droplets is presented as a function of chirality and surface energy (or anchoring). With increasing chirality, a continuous transition is observed from a twisted bipolar structure to a radial spherical structure, all within a narrow range of chirality. During such a transition, a bent structure is predicted by simulations and confirmed by experimental observations. Simulations are also able to capture the dynamics of the quenching process observed in experiments. Consistent with published work, it is found that nanoparticles are attracted to defect regions on the surface of the droplets. For weak anchoring conditions at the nanoparticle surface, ChLC droplets adopt a morphology similar to that of the equilibrium helical phase observed for ChLCs in the bulk. As the anchoring strength increases, a planar bipolar structure arises, followed by a morphological transition to a bent structure. The influence of chirality and surface interactions are discussed in the context of the potential use of ChLC droplets as stimuli-responsive materials for reporting molecular adsorbates.

  18. Segregation of liquid crystal mixtures in topological defects

    Science.gov (United States)

    Rahimi, Mohammad; Ramezani-Dakhel, Hadi; Zhang, Rui; Ramirez-Hernandez, Abelardo; Abbott, Nicholas L.; de Pablo, Juan J.

    2017-04-01

    The structure and physical properties of liquid crystal (LC) mixtures are a function of composition, and small changes can have pronounced effects on observables, such as phase-transition temperatures. Traditionally, LC mixtures have been assumed to be compositionally homogenous. The results of chemically detailed simulations presented here show that this is not the case; pronounced deviations of the local order from that observed in the bulk at defects and interfaces lead to significant compositional segregation effects. More specifically, two disclination lines are stabilized in this work by introducing into a nematic liquid crystal mixture a cylindrical body that exhibits perpendicular anchoring. It is found that the local composition deviates considerably from that of the bulk at the interface with the cylinder and in the defects, thereby suggesting new assembly and synthetic strategies that may capitalize on the unusual molecular environment provided by liquid crystal mixtures.

  19. Regionally Aligned Divisions: Enabling Cultural and Linguistic Competency in Regionally Aligned Forces

    Science.gov (United States)

    2016-05-26

    Regionally Aligned Divisions: Enabling Cultural & Linguistic Competency in... Regionally Aligned Forces A Monograph By MAJ Mikola J. King United States Army School of Advanced Military Studies United States Army Command...From - To) 01-05-2016 SAMS Monograph nJN 2015 - MAY 2016 4. TITLE AND SUBTITLE Sa. CONTRACT NUMBER Regionally Aligned Divisions: Enabling Cultural

  20. Protein sequence alignment analysis by local covariation: coevolution statistics detect benchmark alignment errors.

    Directory of Open Access Journals (Sweden)

    Russell J Dickson

    Full Text Available The use of sequence alignments to understand protein families is ubiquitous in molecular biology. High quality alignments are difficult to build and protein alignment remains one of the largest open problems in computational biology. Misalignments can lead to inferential errors about protein structure, folding, function, phylogeny, and residue importance. Identifying alignment errors is difficult because alignments are built and validated on the same primary criteria: sequence conservation. Local covariation identifies systematic misalignments and is independent of conservation. We demonstrate an alignment curation tool, LoCo, that integrates local covariation scores with the Jalview alignment editor. Using LoCo, we illustrate how local covariation is capable of identifying alignment errors due to the reduction of positional independence in the region of misalignment. We highlight three alignments from the benchmark database, BAliBASE 3, that contain regions of high local covariation, and investigate the causes to illustrate these types of scenarios. Two alignments contain sequential and structural shifts that cause elevated local covariation. Realignment of these misaligned segments reduces local covariation; these alternative alignments are supported with structural evidence. We also show that local covariation identifies active site residues in a validated alignment of paralogous structures. Loco is available at https://sourceforge.net/projects/locoprotein/files/.