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Sample records for aligned c-axis oriented

  1. A method for quantitatively analyzing the angle of direction for arbitral c-axis alignment with retardation measurements

    NASA Astrophysics Data System (ADS)

    Shimoi, Norihiro; Tanaka, Yasumitsu

    2015-01-01

    c-axis alignment in a polymer or crystal structure has drawn attention in numerous scientific and technological applications, including crystals, thin film growth, electro-optic devices, and phase difference optics. We here demonstrate a new approach based on retardation measurement that can obtain the direction of the c-axis alignment. This is employed to visualize the three-dimensional direction of continuous crystals as a thin optical film utilizing a liquid crystal panel, using retardation analysis equipment with high resolution measurement capability. The direction of the c-axis alignment is shown so as to allow a detailed characterization of the direction perpendicular to the plane. In this analysis, the direction of the c-axis alignment is identified, and differences between molecules at inequivalent sites are quantified. The results suggest that the excellent lubrication properties of the c-axis alignment may be due to a significant localization in lateral directions.

  2. Vapor-phase growth of transparent zinc oxide ceramics with c -axis orientation

    SciTech Connect

    Noritake, F.; Yamamoto, N.; Horiguchi, Y. ); Fujitsu, S.; Koumoto, K. ); Yanagida, H. )

    1991-01-01

    Large transparent specimens of polycrystalline zinc oxide with c-axis orientation have been prepared by the vapor transport method. Optical transmittance is 80% to 90% at 800 nm. X-ray diffraction peaks from faces other than (001) are negligible.

  3. Synthesis of c-axis oriented AlN thin films on different substrates: A review

    SciTech Connect

    Iriarte, G.F.

    2010-09-15

    Highly c-axis oriented AlN thin films have been deposited by reactive sputtering on different substrates. The crystallographic properties of layered film structures consisting of a piezoelectric layer, aluminum nitride (AlN), synthesized on a variety of substrates, have been examined. Aluminum nitride thin films have been deposited by reactive pulsed-DC magnetron sputtering using an aluminum target in an Ar/N{sub 2} gas mixture. The influence of the most critical deposition parameters on the AlN thin film crystallography has been investigated by means of X-ray diffraction (XRD) analysis of the rocking curve Full-Width at Half Maximum (FWHM) of the AlN-(0 0 0 2) peak. The relationship between the substrate, the synthesis parameters and the crystallographic orientation of the AlN thin films is discussed. A guide is provided showing how to optimize these conditions to obtain highly c-axis oriented AlN thin films on substrates of different nature.

  4. Flux pinning by a-axis grains in c-axis-oriented Y-Ba-Cu-O films

    NASA Astrophysics Data System (ADS)

    Fuke, H.; Yoshino, H.; Yamazaki, M.; Thanh, T. D.; Nakamura, S.; Ando, K.; Kobayashi, Y.

    1992-05-01

    The relationship between the microstructures and pinning forces is investigated by measuring the magnetic-field dependence and angular dependence of Jc in several kinds of YBCO thin films having different microstructures. A high-Jc value was kept even when the magnetic field was applied perpendicular to the film plane in the case of a c-axis-oriented film which was studded with a-axis-oriented grains. The boundaries between the a-axis-oriented grain and the c-axis-oriented grain are considered to be effective as pinning centers.

  5. Optical properties of c-axis oriented superconducting MgB2 films.

    PubMed

    Tu, J J; Carr, G L; Perebeinos, V; Homes, C C; Strongin, M; Allen, P B; Kang, W N; Choi, E M; Kim, H J; Lee, S I

    2001-12-31

    Temperature dependent optical conductivities and dc resistivity of c-axis oriented superconducting (T(c) = 39.6 K) MgB2 films (approximately 450 nm) have been measured. The normal state ab-plane optical conductivities can be described by the Drude model with a temperature independent Drude plasma frequency of omega(p,D) = 13 600+/-100 cm(-1) or 1.68+/-0.01 eV. The normal state resistivity is fitted by the Bloch-Grüneisen formula with an electron-phonon coupling constant lambda(tr) = 0.13+/-0.02. The optical conductivity spectra below T(c) of these films suggest that MgB2 is a multigap superconductor.

  6. Reduced pressure MOCVD of C-axis oriented BiSrCaCuO thin films

    NASA Technical Reports Server (NTRS)

    Hamaguchi, Norihito; Vigil, J.; Gardiner, R.; Kirlin, P. S.

    1990-01-01

    BiSrCaCuO thin films were deposited on MgO (100) single-crystal substrates by metalorganic chemical vapor deposition at 500 C and 2 torr using fluorinated beta-diketonate complexes of Sr, Ca, and Cu and triphenylbismuth. An inverted vertical reaction chamber allowed uniform film growth over large areas (7.7 cm diameter). The as-deposited films were amorphous mixtures of oxides and fluorides; a two-step annealing protocol (750 C + 850-870 C) was developed which gives c-axis oriented films of Bi2Sr2Ca1Cu2O(x). The postannealed films showed onsets in the resistive transition of 110 K, and zero resistivity was achieved by 83 K. Critical current densities as high as 11,000 A/sq cm were obtained at 25 K.

  7. Quartz c-axis preferred orientations in an experimental shear zone

    SciTech Connect

    Dell'Angelo, L.

    1985-01-01

    Natural rocks which have deformed by simple shear commonly exhibits an asymmetric quartz c-axis fabric which can be a useful kinematic indicator. Although there is some controversy on the sense of asymmetry from theoretical models, fabrics measured from natural rocks generally exhibit an asymmetry with maxima inclined in the direction of shear. The authors have deformed a fine grained quartzite in simple shear in order to determine the relationship of the c-axis fabric to the sense of shear, the foliation and the shear zone boundary. The sample was deformed at 800/sup 0/C, 15 kb and 10/sup -6//sec, where previous axial compression experiments produce small circle girdles symmetrical about sigma/sub 1/ due to basal and prism slip. Original grains are flattened with only a minor amount of recrystallization. A thin sample (.1'' thick) was cut from a right cylinder at 45/sup 0/ to the core axis and placed between two ZrO/sub 2/ pistons with matching 45/sup 0/ faces. In the sheared sample, measurements of grain aspect ratios in vertical sections parallel and perpendicular to the shear direction as well as the angle between the shear zone boundary and the foliation (18/sup 0/) indicate that the deformation has been dominantly simple shear (maximum of 2.8) with only a minor component of pure shear. The preferred orientation pattern is an asymmetric type I crossed girdle which is characterized by two girdles connected through the intermediate strain axis by a single girdle. The asymmetry is defined by stronger maxima inclined in the direction of shear.

  8. The role of the crystal orientation (c-axis) on switching field distribution and the magnetic domain configuration in electrodeposited hcp Co-Pt nanowires

    NASA Astrophysics Data System (ADS)

    Shahid Arshad, Muhammad; Proenca, Mariana P.; Trafela, Spela; Neu, Volker; Wolff, Ulrike; Stienen, Sven; Vazquez, Manuel; Kobe, Spomenka; Žužek Rožman, Kristina

    2016-05-01

    In this report, Co-Pt nanowires (NWs) were produced via potentiostatic electrodeposition into commonly used commercial ordered-alumina and disordered-polycarbonate membranes with similar pore diameters (≈200 nm). The pore diameter of the membranes and the deposition conditions were chosen such that the Co-Pt NWs fabricated into both membranes had a hexagonal close packed (hcp) crystal structure with a crystallographic texturing of the c-axis in the direction perpendicular to the NWs’ long axis; this effect was more pronounced in the alumina membranes. Due to the local fluctuation in electrodeposition conditions (pore diameter, pore shape), we have found a small variation in the c-axis orientations in the plane perpendicular to the NWs’ long axis. Magnetic characterizations suggested that there is uniaxial anisotropy perpendicular to the Co-Pt NWs’ long axis and the small variation in the orientation of the hcp c-axis plays an important role in the switching-field distribution and the magnetic domain structure of the Co-Pt NWs. First order reversal curves (FORCs) revealed week magnetostatic interactions between Co-Pt NWs, thus suggesting that the different pore alignments are not influencing much the magnetic properties in both membranes. The micromagnetic simulation revealed that the transverse-stripe (TS) and longitudinal stripe (LS) domains are energetically most favorable structures in such NWs. This study accentuates the influence of the crystal orientation (c-axis) of the high-anisotropy materials on their functional magnetic properties and thus is of great importance for the fabrication of nanodevices based on such NWs.

  9. Morphology and composition controlled growth of polar c-axis and nonpolar m-axis well-aligned ternary III-nitride nanotube arrays

    NASA Astrophysics Data System (ADS)

    Li, Huijie; Zhao, Guijuan; Kong, Susu; Han, Dongyue; Wei, Hongyuan; Wang, Lianshan; Chen, Zhen; Yang, Shaoyan

    2015-10-01

    Control over the nanostructure morphology and growth orientation is in high demand for fundamental research and technological applications. Herein we report a general strategy to fabricate polar c-axis and nonpolar m-axis well-aligned III-nitride ternary nanotube arrays with controllable morphologies and compositions. By depositing AlN on the InN nanorod array templates and thermally removing the InN templates, InAlN nanotubes can be obtained. Polar c-axis and nonpolar m-axis nanotubes were formed on the c- and r-plane sapphire substrates, respectively. The nanotubes are single crystalline and highly ordered on the substrates, as revealed by X-ray diffraction, electron microscopy, and selected area electron microscopy characterization. It was found that the In droplets on top of the InN nanorods play a critical role in controlling the morphology of the nanotubes. By keeping or removing the In droplets, the obtained nanotubes exhibited both ends open or only one end open. And by varying the AlN deposition temperature, the In composition in the nanotubes can be changed from 0 to 0.29. The nanotube synthesis method is simple and can be applied to the formation of other III-nitride ternary (InGaN, and AlGaN) or quaternary (InAlGaN) alloy nanotube arrays.Control over the nanostructure morphology and growth orientation is in high demand for fundamental research and technological applications. Herein we report a general strategy to fabricate polar c-axis and nonpolar m-axis well-aligned III-nitride ternary nanotube arrays with controllable morphologies and compositions. By depositing AlN on the InN nanorod array templates and thermally removing the InN templates, InAlN nanotubes can be obtained. Polar c-axis and nonpolar m-axis nanotubes were formed on the c- and r-plane sapphire substrates, respectively. The nanotubes are single crystalline and highly ordered on the substrates, as revealed by X-ray diffraction, electron microscopy, and selected area electron microscopy

  10. Lactic acid aided electrochemical deposition of c -axis preferred orientation of zinc oxide thin films: Structural and morphological features

    NASA Astrophysics Data System (ADS)

    Whang, Thou-Jen; Hsieh, Mu-Tao; Tsai, Jia-Ming; Lee, Shyan-Jer

    2011-09-01

    Compact and homogeneous c-axis preferred orientation of zinc oxide (ZnO) films on indium tin oxide (ITO) coated glass have been prepared electrochemically at -1.2 V vs. Ag|AgCl in a weak acidic condition from 0.06 M Zn(NO 3) 2 with 3 mM lactic acid (LA) added. LA was found having strong influence on the electrodeposition of c-axis preferred orientation of zinc oxide films. Other experimental variables such as deposition temperature, potential, and precursor concentration were also conducted in this article. Among these variables, it was found that precursor concentration of zinc nitrate influenced significantly on growth direction and crystal diameter of zinc oxide. Cyclic voltammetry was used to observe the electrochemistry of the deposition. Crystallinities of the films were examined by X-ray diffractometer. The morphologies of zinc oxide films were observed with a field emitting scanning electron microscope. Optical characteristics of zinc oxide layers were measured with UV-vis spectrophotometer. The band gap of the deposited zinc oxide thin films was evaluated from the Tauc relationship of ( αhν) 2 vs. hν, which was found to be 3.31 eV.

  11. Fabrication and Characterization of p-Type SnO Thin Film with High c-Axis Preferred Orientation

    NASA Astrophysics Data System (ADS)

    Pei, Yanli; Liu, Wuguang; Shi, Jingtao; Chen, Zimin; Wang, Gang

    2016-08-01

    p-Type tin monoxide (SnO) thin films with high c-axis preferred orientation have been fabricated on quartz substrate via electron-beam evaporation at 280°C. Subsequently, rapid thermal annealing (RTA) was performed in N2 atmosphere at 400°C to 800°C. Their structural, chemical, optical, and electrical properties were investigated by x-ray diffraction analysis, ultraviolet-visible spectroscopy, scanning electron microscopy, x-ray photoelectron spectroscopy, and Hall-effect measurements. The c-axis-oriented films of Sn-rich SnO presented excellent thermal stability up to RTA at 700°C. Both the crystallization and the hole Hall mobility were enhanced with increasing RTA temperature, with Hall mobility of 16 cm2 V-1 s-1 being obtained after RTA at 700°C. It was considered that the presence of defects and low scattering from grain boundaries contributed to this high Hall mobility. RTA annealing temperature above 700°C induced chemical reaction between SnO and the quartz substrate, with a change of the film to amorphous state with Sn4+ formation.

  12. Fabrication and Characterization of p-Type SnO Thin Film with High c-Axis Preferred Orientation

    NASA Astrophysics Data System (ADS)

    Pei, Yanli; Liu, Wuguang; Shi, Jingtao; Chen, Zimin; Wang, Gang

    2016-11-01

    p-Type tin monoxide (SnO) thin films with high c-axis preferred orientation have been fabricated on quartz substrate via electron-beam evaporation at 280°C. Subsequently, rapid thermal annealing (RTA) was performed in N2 atmosphere at 400°C to 800°C. Their structural, chemical, optical, and electrical properties were investigated by x-ray diffraction analysis, ultraviolet-visible spectroscopy, scanning electron microscopy, x-ray photoelectron spectroscopy, and Hall-effect measurements. The c-axis-oriented films of Sn-rich SnO presented excellent thermal stability up to RTA at 700°C. Both the crystallization and the hole Hall mobility were enhanced with increasing RTA temperature, with Hall mobility of 16 cm2 V-1 s-1 being obtained after RTA at 700°C. It was considered that the presence of defects and low scattering from grain boundaries contributed to this high Hall mobility. RTA annealing temperature above 700°C induced chemical reaction between SnO and the quartz substrate, with a change of the film to amorphous state with Sn4+ formation.

  13. Microstructure of high c-axis oriented stand-alone ZnO self-assembled film.

    PubMed

    Masuda, Yoshitake; Kato, Kazumi

    2009-01-01

    Stand-alone ZnO films were fabricated at air-liquid interfaces. The Microstructures of the films were observed precisely using a transmission electron microscope (TEM) in this study. They were assemblies of nano-sheets having uniform film thickness. The nano-sheets grew down toward the bottom of solutions by the supply of Zn ions from the solutions. X-ray diffraction patterns indicated high c-axis orientation of the films perpendicular to the air-liquid interface. An area of the nano-sheets was magnified for further observation. Electron diffraction patterns and lattice images indicated that the nano-sheets consisted of ZnO crystals. A slight amount of co-precipitated zinc carbonate hydroxide (Zn5(CO3)2(OH)6) was also observed. Their morphologies were drastically changed by electron beam irradiation because of dehydration and crystallization to ZnO.

  14. Shear mode bulk acoustic wave resonator based on c-axis oriented AlN thin film

    NASA Astrophysics Data System (ADS)

    Milyutin, Evgeny; Gentil, Sandrine; Muralt, Paul

    2008-10-01

    A shear mode resonator based on bulk waves trapped in c-axis oriented AlN thin films was fabricated, simulated, and tested. The active 1.55 μm thick AlN layer was deposited on top of an acoustic Bragg reflector composed of SiO2/AlN λ /4 layer pairs. The resonance was excited by means of interdigitated electrodes consisting of 150 nm thick Al lines. Analytical and simulation calculations show that the in-plane electric field excites bulk acoustic wave shear modes that are trapped in such an AlN film slab. The experimental frequency corresponds well to the theoretical one. The evaluated resonance of the fundamental shear mode at 1.86 GHz revealed a coupling of 0.15% and Q-factor of 870 in air and 260 in silicon oil.

  15. Anomalous coherence peak in the microwave conductivity of c-axis oriented MgB2 thin films.

    PubMed

    Jin, B B; Dahm, T; Gubin, A I; Choi, Eun-Mi; Kim, Hyun Jung; Lee, Sung-Ik; Kang, W N; Klein, N

    2003-09-19

    The temperature dependence of the real part of the microwave complex conductivity at 17.9 GHz obtained from surface impedance measurements of two c-axis oriented MgB2 thin films reveals a pronounced maximum at a temperature around 0.6 times the critical temperature. Calculations in the frame of a two-band model based on Bardeen-Cooper-Schrieffer (BCS) theory suggest that this maximum corresponds to an anomalous coherence peak resembling the two-gap nature of MgB2. Our model assumes there is no interband impurity scattering and a weak interband pairing interaction, as suggested by band structure calculations. In addition, the observation of a coherence peak indicates that the pi band is in the dirty limit and dominates the total conductivity of our films.

  16. The c-axis orientation ZnO by ICP enhanced HiPIMS at ambient temperature

    NASA Astrophysics Data System (ADS)

    Zhang, Haitao; chen, Jianyuan; Cherng, Jyhshiarn; Wang, Zhengduo; Liu, Zhongwei; Chen, Qiang

    2016-11-01

    In this paper, a facile method to prepare a high c-axis orientation ZnO film is reported. We combine a high power impulse magnetron sputtering (HiPIMS) with an inductively coupled plasma (ICP) in purpose of improving the reaction activity of Zn species sputtered from HiPIMS with dissociated oxygen, and gaining a high quality ZnO. The diagnostic of optical emission spectroscope (OES), which reveals the Zn+ and atomic oxygen concentrations in plasma, is evident the increasing ionization of Zn and the dissociation of O2 by ICP. After characterizing films grown with and without ICP, likely crystal through x-ray diffraction (XRD), component by energy dispersive spectroscopy (EDS), and morphology by atomic force microscope (AFM), we conclude that ICP assistance is crucial for the ZnO preferentially growth in (002) facet. With ICP assistance ZnO is grown in a big crystal size with a good quality.

  17. Ice crystal c-axis orientation and mean grain size measurements from the Dome Summit South ice core, Law Dome, East Antarctica

    NASA Astrophysics Data System (ADS)

    Treverrow, Adam; Jun, Li; Jacka, Tim H.

    2016-06-01

    We present measurements of crystal c-axis orientations and mean grain area from the Dome Summit South (DSS) ice core drilled on Law Dome, East Antarctica. All measurements were made on location at the borehole site during drilling operations. The data are from 185 individual thin sections obtained between a depth of 117 m below the surface and the bottom of the DSS core at a depth of 1196 m. The median number of c-axis orientations recorded in each thin section was 100, with values ranging from 5 through to 111 orientations. The data from all 185 thin sections are provided in a single comma-separated value (csv) formatted file which contains the c-axis orientations in polar coordinates, depth information for each core section from which the data were obtained, the mean grain area calculated for each thin section and other data related to the drilling site. The data set is also available as a MATLAB™ structure array. Additionally, the c-axis orientation data from each of the 185 thin sections are summarized graphically in figures containing a Schmidt diagram, histogram of c-axis colatitudes and rose plot of c-axis azimuths. All these data are referenced by doi:10.4225/15/5669050CC1B3B and are available free of charge at https://data.antarctica.gov.au.<

  18. Highly c-axis-oriented monocrystalline Pb(Zr, Ti)O₃ thin films on si wafer prepared by fast cooling immediately after sputter deposition.

    PubMed

    Yoshida, Shinya; Hanzawa, Hiroaki; Wasa, Kiyotaka; Esashi, Masayoshi; Tanaka, Shuji

    2014-09-01

    We successfully developed sputter deposition technology to obtain a highly c-axis-oriented monocrystalline Pb(Zr, Ti)O3 (PZT) thin film on a Si wafer by fast cooling (~-180°C/min) of the substrate after deposition. The c-axis orientation ratio of a fast-cooled film was about 90%, whereas that of a slow-cooled (~-40°C/min) film was only 10%. The c-axis-oriented monocrystalline Pb(Zr0.5, Ti0.5)O3 films showed reasonably large piezoelectric coefficients, e(31,f) = ~-11 C/m(2), with remarkably small dielectric constants, ϵ(r) = ~220. As a result, an excellent figure of merit (FOM) was obtained for piezoelectric microelectromechanical systems (MEMS) such as a piezoelectric gyroscope. This c-axis orientation technology on Si will extend industrial applications of PZT-based thin films and contribute further to the development of piezoelectric MEMS. PMID:25167155

  19. Transparent and conducting intrinsic ZnO thin films prepared at high growth-rate with c-axis orientation and pyramidal surface texture

    NASA Astrophysics Data System (ADS)

    Mondal, Praloy; Das, Debajyoti

    2013-12-01

    The growth of ZnO thin films has been optimized by adjusting the intrinsic ion vacancies, by controlling the RF power applied to the plasma in magnetron sputtering. Preferred c-axis oriented intrinsic ZnO films with largest grain size and a hexagonal wurtzite structure, exhibiting high room temperature conductivity, σ ∼ 1.37 S/cm, high transparency, ∼80-90% within 450-800 nm and ∼90-96% within 800-1900 nm, low reflectance (<5% in the visible range) was obtained at a very high deposition rate ∼214 nm/min, at 300 °C, by maintaining higher concentration of Zn interstitials or singly ionized oxygen vacancy, corresponding to an optimized RF power of 200 W. Films have lowest internal stress, smallest dissipation factor defined as ɛ2/ɛ1, and the specific pyramidal surface texture creates enough surface roughness that helps to improve the light scattering from the surface and makes it suitable for efficient use in thin-film silicon solar cells. With increasing RF power beyond 200 W, the Zn-O bond length reduces promptly and the internal stress increases monotonically approaching toward a virtual saturation. The preferred crystallographic alignment shifts from (0 0 2) to (1 0 3), i.e., from c to a-axis orientation, as the surface energy of ZnO crystal changes due to the increase in the Zn-to-ZnO ion ratio in the plasma caused by the plausible de-oxygenation of ZnO at elevated RF powers. Oxygen deficient ZnO films having the flower-like surface texture prepared with a very high deposition rate ∼554 nm/min at 500 W could indeed make the material suitable for gas and chemical sensing applications.

  20. Synthesis and properties of highly c-axis oriented PbTiO3 thin films prepared by and MOCVD method

    NASA Astrophysics Data System (ADS)

    Chen, Xian-Tong; Yamane, Hisanori; Kaya, Kiyoshi

    1992-08-01

    Thin films of PbTiO3 were prepared on MgO(100) substrates by chemical vapor deposition using Pb(C2H5)4 (PbEt) and Ti(OC3H7)4 (TTIP) as sources. With decreasing Pb/Ti molar ratio from 1.2 to 1 the degree of c-axis orientation increased. Highly c-axis oriented PbTiO3 thin films were epitaxially grown at 500°C and 2 kPa. The films were transparent and had a refractive index (n) of 2.64 at 632.8 nm which was about 2% lower than that of a single PbTiO3 crystal (n ≈ 2.7). The films prepared on (100)-oriented Pt electrodes deposited on MgO(100) substrates at 600°C and 2 kPa also showed a prominent c-axis orientation and had a dielectric constant of 90.

  1. SrFeO amorphous underlayer for fabrication of c-axis perpendicularly orientated strontium hexaferrite films by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Masoudpanah, S. M.; Ong, C. K.

    2013-09-01

    A thin amorphous SrFeO underlayer on Si(100) substrate was pulse laser deposited as an underlayer for the growth of c-axis perpendicularly oriented strontium hexaferrite (SrFe12O19) films. The amorphous SrFeO underlayer was deposited at different temperatures in the range from room temperature to 700 °C, while the SrFe12O19 film was deposited at 700 °C. The SrFe12O19 films exhibited slightly perpendicular magnetic anisotropy by the rather higher coercivities in perpendicular direction (Hc⊥) than those for the in-plane direction (Hc||), due to the c-axis perpendicular orientation. The magnetization and coercivities of the SrFe12O19 film increase, but the magnetic anisotropy (ΔHc=Hc⊥-Hc||) increases firstly and then decreases, as the SrFeO underlayer deposition temperature increases.

  2. Growth of thin, c-axis oriented Sr-doped LaP3O9 electrolyte membranes in condensed phosphoric acid solutions

    NASA Astrophysics Data System (ADS)

    Hatada, Naoyuki; Takahashi, Kota; Adachi, Yoshinobu; Uda, Tetsuya

    2016-08-01

    Proton-conducting Sr-doped LaP3O9 has potential application as electrolytes in intermediate temperature fuel cells, but reduction of the electrical resistance of the electrolyte membranes is necessary for practical applications. In this study, we focused on reducing the resistance by reducing the electrolyte thickness, while maintaining a preferable microstructure for proton conduction (c-axis orientation and absence of the small-crystal layer). Thin, c-axis oriented Sr-doped LaP3O9 membranes were successfully obtained in condensed phosphoric acid solutions by a novel "two-step precipitation method". In this method, Sr-doped LaP3O9 powder was artificially deposited on the surface of the carbon paper supports as seeds, and then columnar crystals were grown "downward" in the solutions. We expect that this method will be utilized to produce LaP3O9 electrolyte membranes with lower electrical resistance.

  3. Visual attitude orientation and alignment system

    NASA Technical Reports Server (NTRS)

    Beam, R. A.; Morris, D. B.

    1967-01-01

    Active vehicle optical alignment aid and a passive vehicle three-dimensional alignment target ensure proper orientation and alignment plus control of the closure range and rate between two bodies, one in controlled motion and one at rest.

  4. c-axis preferential orientation of hydroxyapatite accounts for the high wear resistance of the teeth of black carp (Mylopharyngodon piceus)

    NASA Astrophysics Data System (ADS)

    Fu, Jimin; He, Chong; Xia, Biao; Li, Yan; Feng, Qiong; Yin, Qifang; Shi, Xinghua; Feng, Xue; Wang, Hongtao; Yao, Haimin

    2016-03-01

    Biological armors such as mollusk shells have long been recognized and studied for their values in inspiring novel designs of engineering materials with higher toughness and strength. However, no material is invincible and biological armors also have their rivals. In this paper, our attention is focused on the teeth of black carp (Mylopharyngodon piceus) which is a predator of shelled mollusks like snails and mussels. Nanoscratching test on the enameloid, the outermost layer of the teeth, indicates that the natural occlusal surface (OS) has much higher wear resistance compared to the other sections. Subsequent X-ray diffraction analysis reveals that the hydroxyapatite (HAp) crystallites in the vicinity of OS possess c-axis preferential orientation. The superior wear resistance of black carp teeth is attributed to the c-axis preferential orientation of HAp near the OS since the (001) surface of HAp crystal, which is perpendicular to the c-axis, exhibits much better wear resistance compared to the other surfaces as demonstrated by the molecular dynamics simulation. Our results not only shed light on the origin of the good wear resistance exhibited by the black carp teeth but are of great value to the design of engineering materials with better abrasion resistance.

  5. c-axis preferential orientation of hydroxyapatite accounts for the high wear resistance of the teeth of black carp (Mylopharyngodon piceus)

    PubMed Central

    Fu, Jimin; He, Chong; Xia, Biao; Li, Yan; Feng, Qiong; Yin, Qifang; Shi, Xinghua; Feng, Xue; Wang, Hongtao; Yao, Haimin

    2016-01-01

    Biological armors such as mollusk shells have long been recognized and studied for their values in inspiring novel designs of engineering materials with higher toughness and strength. However, no material is invincible and biological armors also have their rivals. In this paper, our attention is focused on the teeth of black carp (Mylopharyngodon piceus) which is a predator of shelled mollusks like snails and mussels. Nanoscratching test on the enameloid, the outermost layer of the teeth, indicates that the natural occlusal surface (OS) has much higher wear resistance compared to the other sections. Subsequent X-ray diffraction analysis reveals that the hydroxyapatite (HAp) crystallites in the vicinity of OS possess c-axis preferential orientation. The superior wear resistance of black carp teeth is attributed to the c-axis preferential orientation of HAp near the OS since the (001) surface of HAp crystal, which is perpendicular to the c-axis, exhibits much better wear resistance compared to the other surfaces as demonstrated by the molecular dynamics simulation. Our results not only shed light on the origin of the good wear resistance exhibited by the black carp teeth but are of great value to the design of engineering materials with better abrasion resistance. PMID:27001150

  6. Fast epitaxial growth of a-axis- and c-axis-oriented YBa 2Cu 3O 7- δ films on (1 0 0) LaAlO 3 substrate by laser chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Zhao, Pei; Ito, Akihiko; Tu, Rong; Goto, Takashi

    2011-02-01

    a-axis- and c-axis-oriented YBa2Cu3O7-δ (YBCO) films were epitaxially grown on (1 0 0) LaAlO3 substrates by laser chemical vapor deposition. The preferred orientation in the YBCO film changed from the a-axis to the c-axis with increasing laser powers from 77 to 158 W (the deposition temperatures from 951 to 1087 K). The a-axis-oriented YBCO film showed in-plane epitaxial growth of YBCO [0 0 1]//LAO [0 0 1], and the c-axis-oriented YBCO film showed that of YBCO [0 1 0]//LAO [0 0 1]. A c-axis-oriented YBCO film with a high critical temperature of 90 K was prepared at a deposition rate of 90 μm h-1, about 2-1000 times higher than that of metalorganic chemical vapor deposition.

  7. Impact of titanium layer and silicon substrate properties on the microstructure of c-axis oriented AlN thin films

    NASA Astrophysics Data System (ADS)

    Wistrela, E.; Bittner, A.; Schmid, U.

    2015-05-01

    Highly c-axis orientated sputter deposited aluminium nitride (AlN) thin films are widely used as piezoelectric layers in micro-electro-mechanical systems (MEMS). Therefore, stable and reliable deposition and patterning of the AlN thin films in the fabrication process of such devices is of utmost importance. In this work, we study the wet chemical etching behavior of highly c-axis oriented AlN layers as well as the film-related residuals after the etching procedure. To investigate the impact of the underlying material on the quality of the AlN films they are either deposited on pure silicon (Si) substrates or on Si substrates covered with a sputter-deposited thin titanium (Ti) film. The 620 nm thin AlN layers are synthesized simultaneously onto both substrate types and subsequently wet-chemical etched in a phosphorous acid based etching solution at a temperature of 80°C. We demonstrate a significant difference in surface roughness of the untreated AlN films when sputter-deposited on Ti or pure Si. Furthermore, we analyze the piezoelectric properties of the deposited films. Although the XRD analyses indicate a high c-axis orientated wurtzite structure for all deposited films, the absolute value of the piezoelectric coefficients |d33| of AlN thin films synthesized on Ti are 0.4-4.3 pC/N, whereas corresponding values of 5.2-6 pC/N are determined at those deposited on pure Si substrates,. Finally, after wet chemically etching a porous, but homogeneous AlN microstructure is observed for samples synthesized onto Ti layers, whereas AlN layers deposited directly on Si substrate are either etched very inhomogenously or almost completely with some etch resistant pyramidal-shaped residues. This might be due to a local change in polarity within the AlN layer.

  8. Properties of c-axis-aligned crystalline indium-gallium-zinc oxide field-effect transistors fabricated through a tapered-trench gate process

    NASA Astrophysics Data System (ADS)

    Asami, Yoshinobu; Kurata, Motomu; Okazaki, Yutaka; Higa, Eiji; Matsubayashi, Daisuke; Okamoto, Satoru; Sasagawa, Shinya; Moriwaka, Tomoaki; Kakehata, Tetsuya; Yakubo, Yuto; Kato, Kiyoshi; Hamada, Takashi; Sakakura, Masayuki; Hayakawa, Masahiko; Yamazaki, Shunpei

    2016-04-01

    To achieve both low power consumption and high-speed operation, we fabricated c-axis-aligned crystalline indium-gallium-zinc oxide (CAAC-IGZO) field-effect transistors (FETs) with In-rich IGZO and common IGZO (\\text{In}:\\text{Ga}:\\text{Zn} = 1:1:1 in atomic ratio) active layers through a simple process using trench gates, and evaluated their characteristics. The results confirm that 60-nm-node IGZO FETs fabricated through a 450 °C process show an extremely low off-state current below the detection limit (at most 2 × 10-16 A) even at a measurement temperature of 150 °C. The results also reveal that the FETs with the In-rich IGZO active layer show a higher on-state current than those with the common IGZO active layer and have excellent frequency characteristics with a cutoff frequency and a maximum oscillation frequency of up to 20 and 6 GHz, respectively. Thus, we demonstrated that CAAC-IGZO FETs with trench gates are promising for achieving both low power consumption and high-speed operation.

  9. Channel length dependence of field-effect mobility of c-axis-aligned crystalline In-Ga-Zn-O field-effect transistors

    NASA Astrophysics Data System (ADS)

    Matsuda, Shinpei; Kikuchi, Erumu; Yamane, Yasumasa; Okazaki, Yutaka; Yamazaki, Shunpei

    2015-04-01

    Field-effect transistors (FETs) with c-axis-aligned crystalline In-Ga-Zn-O (CAAC-IGZO) active layers have extremely low off-state leakage current. Exploiting this feature, we investigated the application of CAAC-IGZO FETs to LSI memories. A high on-state current is required for the high-speed operation of these LSI memories. The field-effect mobility μFE of a CAAC-IGZO FET is relatively low compared with the electron mobility of single-crystal Si (sc-Si). In this study, we measured and calculated the channel length L dependence of μFE for CAAC-IGZO and sc-Si FETs. For CAAC-IGZO FETs, μFE remains almost constant, particularly when L is longer than 0.3 µm, whereas that of sc-Si FETs decreases markedly as L shortens. Thus, the μFE difference between both FET types is reduced by miniaturization. This difference in μFE behavior is attributed to the different susceptibilities of electrons to phonon scattering. On the basis of this result and the extremely low off-state leakage current of CAAC-IGZO FETs, we expect high-speed LSI memories with low power consumption.

  10. Measurement of c-axis angular orientation in calcite (CaCO3) nanocrystals using X-ray absorption spectroscopy

    PubMed Central

    Gilbert, P. U. P. A.; Young, Anthony; Coppersmith, Susan N.

    2011-01-01

    We demonstrate that the ability to manipulate the polarization of synchrotron radiation can be exploited to enhance the capabilities of X-ray absorption near-edge structure (XANES) spectroscopy, to include linear dichroism effects. By acquiring spectra at the same photon energies but different polarizations, and using a photoelectron emission spectromicroscope (PEEM), one can quantitatively determine the angular orientation of micro- and nanocrystals with a spatial resolution down to 10 nm. XANES-PEEM instruments are already present at most synchrotrons, hence these methods are readily available. The methods are demonstrated here on geologic calcite (CaCO3) and used to investigate the prismatic layer of a mollusk shell, Pinctada fucata. These XANES-PEEM data reveal multiply oriented nanocrystals within calcite prisms, previously thought to be monocrystalline. The subdivision into multiply oriented nanocrystals, spread by more than 50°, may explain the excellent mechanical properties of the prismatic layer, known for decades but never explained. PMID:21693647

  11. Growth Behavior of c-Axis-Oriented Epitaxial SrBi2Ta2O9 Films on SrTiO3 Substrates with Atomic Scale Step Structure

    NASA Astrophysics Data System (ADS)

    Takahashi, Kenji; Suzuki, Muneyasu; Yoshimoto, Mamoru; Funakubo, Hiroshi

    2006-02-01

    c-Axis-oriented ultra thin SrBi2Ta2O9 films were epitaxially grown on atomically flat (100)SrTiO3 substrates by pulse-gas-introduced metalorganic chemical vapor deposition, and their growth behavior was observed by atomic force microscopy (AFM). Growth-time-resolved AFM images clearly showed that a completely filled SrBi2Ta2O9 layer was laid under an incompletely grown half-unit-cell two-dimensional (2D)-island layer, indicating the Frank-van der Merwe (layer-by-layer) growth mode. This is the first step-by-step direct observation of layer-by-layer growth of c-axis-oriented bismuth layer-structured dielectric (BLD) films and is considered to be the origin of the thickness-independent smooth surface of c-axis-oriented BLD films.

  12. Synthesis and characterization of 10 nm thick piezoelectric AlN films with high c-axis orientation for miniaturized nanoelectromechanical devices

    SciTech Connect

    Zaghloul, Usama; Piazza, Gianluca

    2014-06-23

    The scaling of piezoelectric nanoelectromechanical systems (NEMS) is challenged by the synthesis of ultrathin and high quality piezoelectric films on very thin electrodes. We report the synthesis and characterization of the thinnest piezoelectric aluminum nitride (AlN) films (10 nm) ever deposited on ultrathin platinum layers (2–5 nm) using reactive sputtering. X-ray diffraction, high-resolution transmission electron microscopy, and fast Fourier transform analyses confirmed the proper crystal orientation, fine columnar texture, and the continuous lattice structure within individual grains in the deposited AlN nanometer thick films. The average extracted d{sub 31} piezoelectric coefficient for the synthesized films is −1.73 pC/N, which is comparable to the reported values for micron thick and highly c-axis oriented AlN films. The 10 nm AlN films were employed to demonstrate two different types of optimized piezoelectric nanoactuators. The unimorph actuators exhibit vertical displacements as large as 1.1 μm at 0.7 V for 25 μm long and 30 nm thick beams. These results have a great potential to realize miniaturized NEMS relays with extremely low voltage, high frequency resonators, and ultrasensitive sensors.

  13. High-coercivity, c-axis oriented Nd{sub 2}Fe{sub 14}B films grown by molecular beam epitaxy

    SciTech Connect

    Keavney, D.J.; Fullerton, E.E.; Pearson, J.E.; Bader, S.D.

    1996-12-31

    Thin films of Nd{sub 2}Fe{sub 14}B with a c-axis orientation and bulk- like magnetic properties were grown with thickness as low as 300 {Angstrom}. They were grown on single-crystal MgO(100) wafers overcoated with epitaxial Mo(100) buffer layers. The 2-14-1 phase were crystallized either by sequential deposition or co-deposition of Fe, Nd, and B from pure elemental evaporation sources onto 600-700 C substrates. Structure of each film was characterized in-situ with RHEED and ex-situ with XRD. For the sequentially deposited films, the in-plane saturation field is 60-70 kOe at 300 K, consistent with the bulk anisotropy field of 73 kOe. The spin-reorientation transition at 135 K can also be clearly seen in the in-plane and out-of-plane magnetization vs temperature data. The out-of-plane coercivities range from 15-20 kOe at 20 K and 3-8 kOe at 300 K. Co-deposition results in a multiphase structure, with Nd{sub 2}Fe{sub 14}B now the minority phase. The multiphase structure results in reduced perpendicular anisotropy.

  14. Highly c-axis oriented growth of GaN film on sapphire (0001) by laser molecular beam epitaxy using HVPE grown GaN bulk target

    SciTech Connect

    Kushvaha, S. S.; Kumar, M. Senthil; Maurya, K. K.; Dalai, M. K.; Sharma, Nita D.

    2013-09-15

    Growth temperature dependant surface morphology and crystalline properties of the epitaxial GaN layers grown on pre-nitridated sapphire (0001) substrates by laser molecular beam epitaxy (LMBE) were investigated in the range of 500–750 °C. The grown GaN films were characterized using high resolution x-ray diffraction, atomic force microscopy (AFM), micro-Raman spectroscopy, and secondary ion mass spectroscopy (SIMS). The x-ray rocking curve full width at a half maximum (FWHM) value for (0002) reflection dramatically decreased from 1582 arc sec to 153 arc sec when the growth temperature was increased from 500 °C to 600 °C and the value further decreased with increase of growth temperature up to 720 °C. A highly c-axis oriented GaN epitaxial film was obtained at 720 °C with a (0002) plane rocking curve FWHM value as low as 102 arc sec. From AFM studies, it is observed that the GaN grain size also increased with increasing growth temperature and flat, large lateral grains of size 200-300 nm was obtained for the film grown at 720 °C. The micro-Raman spectroscopy studies also exhibited the high-quality wurtzite nature of GaN film grown on sapphire at 720 °C. The SIMS measurements revealed a non-traceable amount of background oxygen impurity in the grown GaN films. The results show that the growth temperature strongly influences the surface morphology and crystalline quality of the epitaxial GaN films on sapphire grown by LMBE.

  15. In-plane and out-of-plane dissipation in {ital c}-axis-oriented (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O {sub x} silver-sheathed tapes

    SciTech Connect

    Xu, G.; Sun, Y.; Du, J. |; Zhou, Y.; Zeng, R.; Fu, X.; Hua, P.

    1997-02-01

    The temperature dependence of the out-of-plane and in-plane resistance of a c-axis-oriented (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O {sub x} silver-sheathed tape with high critical current density (J{sub c}{gt}2{times}10{sup 4} A/cm{sup 2}, 77 K, 0 T) has been investigated under applied fields up to 0.9 T. It is found that the in-plane and the out-of-plane resistance transitions are quite different: (1) The out-of-plane zero resistance temperature is much higher than the in-plane one, i.e., T{sub c}{sup ab}(H){lt}T{sub c}{sup c}(H), and the difference increases with magnetic field; (2) the out-of-plane zero resistance temperature corresponds to the c-axis decoupling temperature. These phenomena are attributed to different dissipation mechanisms. The in-plane dissipation at low temperature results from the thermally activated flux{endash}flow, while the out-of-plane dissipation originates from the Josephson junction dissipation of weakly coupled c-axis grain boundaries and/or intrinsic Josephson junctions.{copyright} {ital 1997 American Institute of Physics.}

  16. Orienting members in a preselected rotary alignment

    DOEpatents

    Williams, Ray E.

    1987-01-01

    An apparatus for orienting members and for maintaining their rotary alignment during orienting members. The apparatus comprises first and second cylindrical elements, a rotation prevention element, a collar and a retainer. Each element has an outside wall, and first and second ends, each end having an outside edge. The first element has portions defining a first plurality of notches located at the outside edge of its first end. An external threaded portion is on the outside wall of the first element and next to the first plurality of notches. The second element has portions defining a second plurality of notches located at the outside edge of its first end. The first plurality has a different number than the second plurality. The first ends of the first and second tubes have substantially the same outside diameter and are abutted during connection so that a cavity is formed whenever first and second tube notches substantially overlap. A rotation prevention element is placed in the cavity to prevent rotation of the first and second elements. A collar with an internal threaded portion is slidably disposed about the second element. The internal threaded portion engages the external threaded portion of the first element to connect the elements. A lip connected to the collar prevents separation of the collar from the second element.

  17. Influence of c-axis orientation and scandium concentration on infrared active modes of magnetron sputtered Sc{sub x}Al{sub 1−x}N thin films

    SciTech Connect

    Mayrhofer, P. M.; Bittner, A.; Schmid, U.; Eisenmenger-Sittner, C.; Euchner, H.

    2013-12-16

    Doping of wurtzite aluminium nitride (AlN) with scandium (Sc) significantly enhances the piezoelectric properties of AlN. Sc{sub x}Al{sub 1−x}N thin films with different Sc concentrations (x = 0 to 0.15) were deposited by DC reactive magnetron sputtering. Infrared (IR) absorbance spectroscopy was applied to investigate the Sc concentration dependent shift of the IR active modes E{sub 1}(TO) and A{sub 1}(TO). These results are compared to ab initio simulations, being in excellent agreement with the experimental findings. In addition, IR spectroscopy is established as an economical and fast method to distinguish between thin films with a high degree of c-axis orientation and those exhibiting mixed orientations.

  18. Investigation on orientation, epitaxial growth and microstructure of a-axis-, c-axis-, (103)/(110)- and (113)-oriented YBa2Cu3O7-δ films prepared on (001), (110) and (111) SrTiO3 single crystal substrates by spray atomizing and coprecipitating laser chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Zhao, Pei; Wang, Ying; Huang, Zhi liang; Mao, Yangwu; Xu, Yuan Lai

    2015-04-01

    a-axis-, c-axis-, (103)/(110)- and (113)-oriented YBa2Cu3O7-δ (YBCO) films were pareared by spray atomizing and coprecipitating laser chemical vapor deposition. The surface of the a-axis-oriented YBCO film consisted of rectangular needle-like grains whose in-plane epitaxial growth relationship was YBCO [100] // STO [001] (YBCO [001] // STO [100]), and that of the c-axis-oriented YBCO film consisted of dense flat surface with epitaxial growth relationship of YBCO [001] // STO [001] (YBCO [100] //STO [100]). For the (103)/(110)-oriented and (113)-oriented YBCO film, they showed wedge-shaped and triangle-shaped grains, with corresponding in-plane epitaxial growth relationship of YBCO [110] // STO [110] (YBCO [010] // STO [010]) and YBCO [100] // STO [100] (YBCO [113] // STO [111], respectively.

  19. Optimal molecular alignment and orientation through rotational ladder climbing

    NASA Astrophysics Data System (ADS)

    Salomon, Julien; Dion, Claude M.; Turinici, Gabriel

    2005-10-01

    We study the control by electromagnetic fields of molecular alignment and orientation in a linear, rigid-rotor model. With the help of a monotonically convergent algorithm, we find that the optimal field is in the microwave part of the spectrum and acts by resonantly exciting the rotation of the molecule progressively from the ground state, i.e., by rotational ladder climbing. This mechanism is present not only when maximizing orientation or alignment, but also when using prescribed target states that simultaneously optimize the efficiency of orientation/alignment and its duration. The extension of the optimization method to consider a finite rotational temperature is also presented.

  20. Optimal molecular alignment and orientation through rotational ladder climbing.

    PubMed

    Salomon, Julien; Dion, Claude M; Turinici, Gabriel

    2005-10-01

    We study the control by electromagnetic fields of molecular alignment and orientation in a linear, rigid-rotor model. With the help of a monotonically convergent algorithm, we find that the optimal field is in the microwave part of the spectrum and acts by resonantly exciting the rotation of the molecule progressively from the ground state, i.e., by rotational ladder climbing. This mechanism is present not only when maximizing orientation or alignment, but also when using prescribed target states that simultaneously optimize the efficiency of orientation/alignment and its duration. The extension of the optimization method to consider a finite rotational temperature is also presented. PMID:16238394

  1. Spherulitic (c-axis) Growth for Terrestrial (Mauna Kea, Hawaii) and Martian Hematite "blueberries"

    NASA Technical Reports Server (NTRS)

    Golden, D. C.; Ming, D. W.; Morris, R. V.

    2006-01-01

    Hematite concentrations observed by Thermal Emission Spectrometer (TES) onboard Mars Global Surveyor were considered a possible indicator for aqueous processes on Mars. Observations made by Opportunity show that the hematite at Meridiani Planum is present as spherules ( blueberries) and their fragments. The internal structure of the hematite spherules is not discernable at the resolution limit (approx.30 m/pixel) of Opportunity s Microscopic Imager (MI). A terrestrial analog for martian hematite spherules are spherules from hydrothermally altered and sulfate-rich tephra from the summit region of Mauna Kea volcano, Hawaii. The objective of this study is to determine the crystal growth fabric of the Mauna Kea hematite spherules using transmission electron microscopy (TEM) techniques and to relate that crystalline fabric to the observed TES signature of Meridiani Planum "blueberries." TEM analysis of Mauna Kea spherules exhibited a radial growth pattern consisting of "fibrous" hematite with the c-axis of hematite particles aligned along the elongation direction of the hematite fibers. The individual fibers appear to be made of coalesced nano-particles of hematite arranged with their c-axis oriented radially to form a spherical structure. Lattice fringes suggest long-range order across particles and along fibers. According to interpretations of thermal emission spectra for Meridian Planum hematite, the absence of a band at approx. 390/cm implies a geometry where c-face emission dominates. Because the c-face is perpendicular to the c-axis, this is precisely the geometry for the Mauna Kea spherules because the c-axis is aligned parallel to their radial growth direction. Therefore, we conclude as a working hypothesis that the martian spherules also have radial, c-axis growth pattern on a scale that is too small to be detected by the MER MI. Furthermore, by analogy with the Mauna Kea spherules, the martian blueberries could have formed during hydrothermal alteration of

  2. Preparation and properties of highly c-axis-oriented Sr0.6Ba0.4Nb2O6 thin films by the sol-gel process

    NASA Astrophysics Data System (ADS)

    Shen, Zhiru; Ye, Hui; Zou, Tong; Guo, Bing

    2005-01-01

    Highly oriented ferroelectric strontium barium niobate (Sr0.6Ba0.4Nb2O6) thin films were prepared on P-type Si(100) substrate by the Sol-Gel process. The XRD patterns of the SBN films show that SBN film prepared by using NbCl5, KOH as raw materials performed a highly c-axis preferred orientation perpendicular to the Si substrate, better than films that was prepared using Nb(OC2H5)5 as starting agents. It may be duo to the existence of the potassium ion that not be filtered out completely during the preparation of the niobium alkoxide. The characteristics of D-F and C-V curves were obtained for SBN/Si film. The film exhibits high dielectric constant. In order to investigate ferroelectric characteristics further, the P-E loops of the SBN/Pt/Si were also measured. The films show better optical properties, transmittance of Sr0.6Ba0.4Nb2O6 films on MgO(001) and SiO2 substrates was more than 60% at the range from 450 to 850nm, refractive index was measured to be 2.14 and 2.12 on the MgO and SiO2 substrate at 633nm respectively.

  3. Orientational Alignment of Amyloidogenic Proteins in Pre-Aggregated Solutions

    NASA Astrophysics Data System (ADS)

    Schröder, C.; Steinhauser, O.; Sasisanker, P.; Weingärtner, H.

    2015-03-01

    In the present study we combine dielectric relaxation spectroscopy with generalized Born simulations to explore the role of orientational order for protein aggregation in solutions of bovine pancreatic insulin at various p H conditions. Under aggregation-prone conditions at low p H , insulin monomers prefer antiparallel dipole alignments, which are consistent with the orientation of the monomeric subunits in the dimer structure. This alignment is also true for two dimers, suggesting that already at moderate protein concentrations the species assemble in equilibrium clusters, in which the molecules adopt preferred orientations also found for the protomers of the corresponding oligomers.

  4. Orientation of thin YBa2Cu3O7-ALIGN="MIDDLE" SRC="http://www.iop.org/icons/Journals/Common/ delta.gif" ALT="delta" />/YSZ films characterization by micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, M. S.; Shen, Z. X.; Zhou, W. Z.; Xu, S. Y.; Ong, C. K.

    1999-05-01

    Micro-Raman scattering of thin YBa2Cu3O7-icons/Journals/Common/delta" ALT="delta" ALIGN="MIDDLE"/> films of various thicknesses, deposited by pulsed laser deposition on the yttrium-stabilized zirconia (001) substrates, was carried out at different scattering geometries. The fraction of c-axis orientation of the films was calculated from the intensity ratio of the O(2,3)-B1g and O(4)-Ag modes. It is shown that it is strongly dependent on the film thickness and the highest fraction of c-axis orientation occurs for film thickness around 80 nm. The lower c-axis fraction for thinner films was explained by the simultaneous growth of a- and c-axis-oriented grains at the interface region, while the lower c-axis fraction for thicker films was due to the faults and voids in the films. Several a- and b-axis in-plane orientations have been identified using polarized Raman spectra.

  5. The impact of argon admixture on the c-axis oriented growth of direct current magnetron sputtered Sc{sub x}Al{sub 1−x}N thin films

    SciTech Connect

    Mayrhofer, P. M.; Bittner, A.; Schmid, U.; Eisenmenger-Sittner, C.; Stöger-Pollach, M.

    2014-05-21

    The piezoelectric properties of wurtzite aluminium nitride (w-AlN) are enhanced by alloying with scandium (Sc), thus offering superior properties for applications in micro electro-mechanical systems devices. Sc{sub x}Al{sub 1−x}N thin films have been prepared by DC reactive magnetron sputtering on Si (100) substrates from a single target. When targeting a concentration range from x = 0 up to x = 0.15, the preparation conditions have been optimized by varying the Ar/N{sub 2} ratio in the sputtering gas. To incorporate an increasing Sc concentration, a higher Ar/N{sub 2} ratio has to be applied during the deposition process. Hence, the argon concentration in the sputtering gas becomes a crucial parameter for microstructure-related parameters. To determine phase purity, degree of c-axis orientation, lattice parameter, and grain size, the Sc{sub x}Al{sub 1−x}N thin films were investigated by techniques, such as scanning electron microscopy, transmission electron microscopy, and X-ray diffraction.

  6. Orientation alignment of epitaxial LiCoO2 thin films on vicinal SrTiO3 (100) substrates

    NASA Astrophysics Data System (ADS)

    Nishio, Kazunori; Ohnishi, Tsuyoshi; Mitsuishi, Kazutaka; Ohta, Narumi; Watanabe, Ken; Takada, Kazunori

    2016-09-01

    LiCoO2 is epitaxially grown on SrTiO3 (100) substrates with (104) orientation. Because the LiCoO2 film is grown with its c-axis parallel to four equivalent <111> axes of the SrTiO3, the (104)-oriented film exhibits four-domain structure on the SrTiO3 (100) substrate. Introducing off-cut angle to the substrate surface breaks the equivalency between the four <111> axes of the SrTiO3 substrate to induce preferential growth of specific orientation with the c-axis in a descending direction of off-cut surface. Increasing off-cut angle and lowering deposition rate promote the preferential growth, because they facilitate step-flow growth mode, and finally align the c-axes in the domains completely into one <111> direction of the SrTiO3 substrate. The LiCoO2 film delivers a discharge capacity of 90 mAh g-1 at a low discharge rate of 0.01 C, and 25% of capacity is kept even at a high rate of discharge with 100 C.

  7. Molecular alignment and orientation with a hybrid Raman scattering technique

    NASA Astrophysics Data System (ADS)

    Bustard, Philip J.; Lausten, R.; Sussman, Benjamin J.

    2012-11-01

    We demonstrate a scheme for the preparation of molecular alignment and angular momentum orientation using a hybrid combination of two limits of Raman scattering. First a weak, impulsive pump pulse initializes the system via the nonresonant dynamic Stark effect. Then, having overcome the influence of the vacuum fluctuations, an amplification pulse selectively enhances the initial coherences by transient stimulated Raman scattering, generating alignment and angular momentum orientation of molecular hydrogen. The amplitude and phase of the resulting coherent dynamics are experimentally probed, indicating an amplification factor of 4.5. An analytic theory is developed to model the dynamics.

  8. Classroom EFL Writing: The Alignment-Oriented Approach

    ERIC Educational Resources Information Center

    Haiyan, Miao; Rilong, Liu

    2016-01-01

    This paper outlines the alignment-oriented approach in classroom EFL writing. Based on a review of the characteristics of the written language and comparison between the product-focused approach and the process-focused approach, the paper proposes a practical classroom procedure as to how to teach EFL writing. A follow-up empirical study is…

  9. The Shapes, Orientation, and Alignment of Galactic Dark Matter Subhalos

    NASA Astrophysics Data System (ADS)

    Kuhlen, Michael; Diemand, Jürg; Madau, Piero

    2007-12-01

    We present a study of the shapes, orientations, and alignments of Galactic dark matter subhalos in the Via Lactea simulation of a Milky Way-size ΛCDM host halo. Whereas isolated dark matter halos tend to be prolate, subhalos are predominantly triaxial. Overall subhalos are more spherical than the host halo, with minor-to-major and intermediate-to-major axis ratios of 0.68 and 0.83, respectively. Like isolated halos, subhalos tend to be less spherical in their central regions. The principal axis ratios are independent of subhalo mass when the shapes are measured within a physical scale such as rVmax, the radius of the peak of the circular velocity curve. Subhalos tend to be slightly more spherical closer to the host halo center. The spatial distribution of the subhalos traces the prolate shape of the host halo when they are selected by the largest Vmax they ever had, i.e., before they experienced strong tidal mass loss. The subhalos' orientation is not random: the major axis tends to align with the direction toward the host halo center. This alignment disappears for halos beyond 3r200 and is more pronounced when the shapes are measured in the outer regions of the subhalos. The radial alignment is preserved during a subhalo's orbit and they become elongated during pericenter passage, indicating that the alignment is likely caused by the host halo's tidal forces. These tidal interactions with the host halo act to make subhalos rounder over time.

  10. Alignment and defect structures in oriented phosphatidylcholine multilayers.

    PubMed Central

    Asher, S A; Pershan, P S

    1979-01-01

    The alignment of dilauryl-, dimyristoyl-, and dipalmitoylphosphatidylcholine at various water concentrations into large oriented monodomain multilayers by annealing at elevated temperatures (Powers and Clark, 1975, Proc. Natl. Acad. Sci. U.S.A. 72:840; Powers and Pershan. 1977. Biophys. J. 20:137) is accompanied by the formation and subsequent dissolution of various defect structures. Some of these defects appear similar to those observed in thermotropic and other lyotropic liquid crystals, reflecting the lamellar structure of these materials. The formation and evolution of defects during the alignment of the lipids into the defect-free, monodomain, multilamellar geometry is studied using polarized microscopy. A combination of polarized and dark-field microscopy facilitated characterization of the defects; specific structural models are proposed. A new alignment technique involving compression and dilation of the lipid, which effects sample alignment at temperatures that are lower than those required by the Powers technique, is described. Lower temperature alignment avoids thermal decomposition that will sometimes occur if the lipid is maintained at elevated temperatures for prolonged periods. With this technique, samples (80 micrometer thick) of dilaurylphosphatidylcholine with 20% water by weight were aligned at room temperature. Images FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 FIGURE 10 FIGURE 11 FIGURE 12 FIGURE 13 FIGURE 14 FIGURE 15 PMID:263691

  11. Luminescence and dielectric properties of c-axis oriented (Bi1.90Eu0.10)(V1-zMoz)O5.5 ferroelectric thin films

    NASA Astrophysics Data System (ADS)

    Xie, Wei; Zou, Changwei; Xie, Mubiao; Bao, Dinghua

    2016-05-01

    (Bi1.90Eu0.10)(V1-zMoz)O5.5 (z = 0, 0.05, 0.10, 0.15 and 0.20) thin films with c-axis oriented were prepared on Pt(111)/Ti/SiO2/Si substrates by using chemical solution deposition method. The effect of Mo6+ concentration on the structure, luminescence properties and dielectric properties of the thin films were characterized systematically. X-ray diffraction data indicates that the thin films with low Mo6+-doping content can remain Bi2VO5.5 structure. When the Mo6+-doping content z reaches to 0.15, the thin films are a mixture of diphase with the main phase Bi2VO5.5 and secondary phase Bi2MoO6. Under UV irradiation, all the thin films emit a bright red or orange emission which origin from Eu3+. With increasing Mo6+-doping content z, the relative intensity of the Red and Orange emissions show obviously change. The value of Red/Orange ratio first decrease, and it reached minimum when z is 0.15, then it recover to the initial value. The variation trend of the Red/Orange ratio reflects the change of the lattice symmetry. Dielectric constant of the thin films increased with the increasing of the Mo6+ concentration while dielectric loss decreased. The decrease of the quantities of oxygen vacancies and the generation of Bi2MoO6 phase are responsible for the improvement of electric properties. These results explain that Eu3+ion can be used as an effective luminescent probe in (Bi1.90Eu0.10)(V1-zMoz)O5.5 (z = 0, 0.05, 0.10, 0.15 and 0.20) thin films, and the electric properties of the thin films can be improved by Mo6+ doping.

  12. Orientation-to-alignment conversion and spin squeezing

    NASA Astrophysics Data System (ADS)

    Rochester, S. M.; Ledbetter, M. P.; Zigdon, T.; Wilson-Gordon, A. D.; Budker, D.

    2012-02-01

    The relationship between orientation-to-alignment conversion (a form of atomic polarization evolution induced by an electric field) and the phenomenon of spin squeezing is demonstrated. A “stretched” state of an atom or molecule with maximum angular-momentum projection along the quantization axis possesses orientation and is a quantum-mechanical minimum-uncertainty state, where the product of the equal uncertainties of the angular-momentum projections on two orthogonal directions transverse to the quantization axis is the minimum allowed by the uncertainty relation. Application of an electric field for a short time induces orientation-to-alignment conversion and produces a spin-squeezed state, in which the quantum state essentially remains a minimum-uncertainty state, but the uncertainties of the angular-momentum projections on the orthogonal directions are unequal. This property can be visualized using the angular-momentum probability surfaces, where the radius of the surface is given by the probability of measuring the maximum angular-momentum projection in that direction. Brief remarks are also given concerning collective-spin squeezing and quantum nondemolition measurements.

  13. Orientation, alignment, and polytype control in epitaxial growth of SiC nanowires for electronics application in harsh environments

    NASA Astrophysics Data System (ADS)

    Koshka, Yaroslav; Thirumalai, Rooban Venkatesh K. G.; Krishnan, Bharat K.; Levin, Igor; Merrett, J. Neil; Davydov, Albert V.

    2013-09-01

    SiC nanowires (NWs) are attractive building blocks for the next generation electronic devices since silicon carbide is a wide bandgap semiconductor with high electrical breakdown strength, radiation resistance, mechanical strength, thermal conductivity, chemical stability and biocompatibility. Epitaxial growth using metal-catalyst-based vapor-liquid-solid mechanism was employed for SiC NW growth in this work. 4H-SiC substrates having different crystallographic orientations were used in order to control NW alignment and polytype. A new technique based on vapor-phase delivery of the metal catalyst was developed to facilitate control of the NW density. Both 4H and 3C polytypes with a strong stacking disorder were obtained. The 4H and 3C NWs had different orientations with respect to the substrate. 4H NWs grew perpendicular to the c-plane of the substrate. The stacking faults (SFs) in these nanowires were perpendicular to the [0001] nanowire axes. All 3C NWs grew at 20° with respect to the substrate c-plane, and their projections on the c-plane corresponded to one of the six equivalent ⟨101-0⟩ crystallographic directions. All six orientations were obtained simultaneously when growing NWs on the (0001) substrate surface, while only one or two NW orientations were observed when growing NWs on any particular crystallographic plane parallel to the c-axis of the substrate. Growth on {101-0} surfaces resulted in only one NW orientation, thereby producing well-aligned NW arrays. Preliminary measurements of the NW electrical conductivity are reported utilizing two-terminal device geometry.

  14. Co-Orientation: Quantifying Simultaneous Co-Localization and Orientational Alignment of Filaments in Light Microscopy.

    PubMed

    Nieuwenhuizen, Robert P J; Nahidiazar, Leila; Manders, Erik M M; Jalink, Kees; Stallinga, Sjoerd; Rieger, Bernd

    2015-01-01

    Co-localization analysis is a widely used tool to seek evidence for functional interactions between molecules in different color channels in microscopic images. Here we extend the basic co-localization analysis by including the orientations of the structures on which the molecules reside. We refer to the combination of co-localization of molecules and orientational alignment of the structures on which they reside as co-orientation. Because the orientation varies with the length scale at which it is evaluated, we consider this scale as a separate informative dimension in the analysis. Additionally we introduce a data driven method for testing the statistical significance of the co-orientation and provide a method for visualizing the local co-orientation strength in images. We demonstrate our methods on simulated localization microscopy data of filamentous structures, as well as experimental images of similar structures acquired with localization microscopy in different color channels. We also show that in cultured primary HUVEC endothelial cells, filaments of the intermediate filament vimentin run close to and parallel with microtubuli. In contrast, no co-orientation was found between keratin and actin filaments. Co-orientation between vimentin and tubulin was also observed in an endothelial cell line, albeit to a lesser extent, but not in 3T3 fibroblasts. These data therefore suggest that microtubuli functionally interact with the vimentin network in a cell-type specific manner.

  15. Orientation and alignment effects in electron-induced ionization of a single oriented water molecule

    SciTech Connect

    Champion, C.; Rivarola, R. D.

    2010-10-15

    We here report a theoretical study about the orientation effect on the total ionization cross sections for a single oriented water molecule. The theoretical description of the ionization process is performed within the first Born framework with a collisional system including an initial state composed of a projectile and a water target molecule described by a plane wave and an accurate one-center molecular wave function, respectively, and a final state constituted by a slow ejected electron represented by a Coulomb wave and a scattered (fast) electron projectile described by a plane wave. Secondary electron energetic distributions as well as total cross sections are then compared for particular target configurations pointing out strong alignment and orientation effects on the description of the ionization process.

  16. Temporal Effects of Alignment in Text-Based, Task-Oriented Discourse

    ERIC Educational Resources Information Center

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

    2015-01-01

    Communicative alignment refers to adaptation to one's communication partner. Temporal aspects of such alignment have been little explored. This article examines temporal aspects of lexical and syntactic alignment (i.e., tendencies to use the interlocutor's lexical items and syntactic structures) in task-oriented discourse. In particular, we…

  17. Orthogonally oriented scaffolds with aligned fibers for engineering intestinal smooth muscle

    PubMed Central

    Kobayashi, Masae; Lei, Nan Ye; Wang, Qianqian; Wu, Benjamin M.; Dunn, James C.Y.

    2015-01-01

    Controlling cellular alignment is critical in engineering intestines with desired structure and function. Although previous studies have examined the directional alignment of cells on the surface (x-y plane) of parallel fibers, quantitative analysis of the cellular alignment inside implanted scaffolds with oriented fibers has not been reported. This study examined the cellular alignment in the x-z and y-z planes of scaffolds made with two layers of orthogonally oriented fibers. The cellular orientation inside implanted scaffolds was evaluated with immunofluorescence. Quantitative analysis of coherency between cell orientation and fiber direction confirmed that cells aligned along the fibers not only on the surface (x-y plane) but also inside the scaffolds (x-z & y-z planes). Our study demonstrated that two layers of orthogonally aligned scaffolds can generate the histological organization of cells similar to that of intestinal circular and longitudinal smooth muscle. PMID:26001072

  18. Vortex-aligned fullerene nanowhiskers as a scaffold for orienting cell growth.

    PubMed

    Krishnan, Venkata; Kasuya, Yuki; Ji, Qingmin; Sathish, Marappan; Shrestha, Lok Kumar; Ishihara, Shinsuke; Minami, Kosuke; Morita, Hiromi; Yamazaki, Tomohiko; Hanagata, Nobutaka; Miyazawa, Kun'ichi; Acharya, Somobrata; Nakanishi, Waka; Hill, Jonathan P; Ariga, Katsuhiko

    2015-07-22

    A versatile method for the rapid fabrication of aligned fullerene C60 nanowhiskers (C60NWs) at the air-water interface is presented. This method is based on the vortex motion of a subphase (water), which directs floating C60NWs to align on the water surface according to the direction of rotational flow. Aligned C60NWs could be transferred onto many different flat substrates, and, in this case, aligned C60NWs on glass substrates were employed as a scaffold for cell culture. Bone forming human osteoblast MG63 cells adhered well to the C60NWs, and their growth was found to be oriented with the axis of the aligned C60NWs. Cells grown on aligned C60NWs were more highly oriented with the axis of alignment than when grown on randomly oriented nanowhiskers. A study of cell proliferation on the C60NWs revealed their low toxicity, indicating their potential for use in biomedical applications.

  19. Synthesis and orientation of barium hexaferrite ceramics by magnetic alignment

    NASA Astrophysics Data System (ADS)

    Autissier, Denis

    1990-01-01

    Particles of Ba 2Mn xZn 2- xFe 12O 22 with planar structure were prepared by chemical precipitation. They were processed by sleep casting in presence of a magnetic field. The degree of alignment was improved by a special sintering treatment. By this procedure an alignment as high as 99.9% is obtained.

  20. Fabrication of c-axis Oriented Epitaxial EuBa2Cu3O7-δ and EuBa2Cu4O8 Films on SrTiO3 (100) Substrate by Molten Hydroxide Method at 450°C

    NASA Astrophysics Data System (ADS)

    Miyachi, Y.; Funaki, S.; Yamada, Y.

    EuBa2Cu3O7-δ (Eu123) and EuBa2Cu4O8 (Eu124) films oriented in c-axis were deposited on SrTiO3 (100) substrates with eutectic NaOH-KOH flux at 450 °C. Synthesized phase has changed by using various types of barium source materials. Pure Eu124 films showed superconducting transition at ∼70 K, zero-resistance was not observed for Eu123/124 two-phase films. One of the possible reasons of this is Eu/Ba substitution of Eu123 phase. According to Tc of the Eu124, the molten hydroxide method enables to deposit high-quality Eu124 films.

  1. Lithography-assisted alignment control for preparation of mesoporous silica films with uniaxially oriented mesochannels.

    PubMed

    Yamauchi, Yusuke; Ishihara, Shinsuke; Suzuki, Norihiro; Wu, Kevin C W

    2014-03-01

    We report the lithography-assisted alignment control of one-dimensional (1D) mesochannels. The effectiveness on both nonionic and cationic surfactants is discussed, and a continuous film with fully uniaxially oriented mesochannels is also successfully prepared.

  2. The analysis of quartz c-axis fabrics using a modified optical microscope.

    PubMed

    Wilson, C J L; Russell-Head, D S; Kunze, K; Viola, G

    2007-07-01

    A new fully automated microfabric analyzer (MiFA) is described that can be used for the fast collection of high-resolution spatial c-axis orientation data from a set of digital polarized light images. At the onset of an analysis the user is presented with an axial-distribution diagram (AVA -'Achsenverteilungsanalyse') of a thin section. It is then a simple matter to build-up c-axis pole figures from selected areas of interest. The c-axis inclination and colatitudes at any pixel site is immediately available to create bulk fabric diagrams or to select measurements in individual areas. The system supports both the interactive selection of c-axis measurement sites and grid array selection. A verification process allows the operator to exclude dubious measurements due to impurities, grain boundaries or bubbles. We present a comparison of bulk and individual c-axis MiFA measurements to pole figures measured with an X-ray texture goniometer and to data collected from a scanning electron microscope furnished with electron backscatter diffraction (EBSD) facility. A second sample, an experimentally deformed quartzite, illustrates that crystal orientations can be precisely linked to any location within an individual grain.

  3. Vortex-aligned fullerene nanowhiskers as a scaffold for orienting cell growth.

    PubMed

    Krishnan, Venkata; Kasuya, Yuki; Ji, Qingmin; Sathish, Marappan; Shrestha, Lok Kumar; Ishihara, Shinsuke; Minami, Kosuke; Morita, Hiromi; Yamazaki, Tomohiko; Hanagata, Nobutaka; Miyazawa, Kun'ichi; Acharya, Somobrata; Nakanishi, Waka; Hill, Jonathan P; Ariga, Katsuhiko

    2015-07-22

    A versatile method for the rapid fabrication of aligned fullerene C60 nanowhiskers (C60NWs) at the air-water interface is presented. This method is based on the vortex motion of a subphase (water), which directs floating C60NWs to align on the water surface according to the direction of rotational flow. Aligned C60NWs could be transferred onto many different flat substrates, and, in this case, aligned C60NWs on glass substrates were employed as a scaffold for cell culture. Bone forming human osteoblast MG63 cells adhered well to the C60NWs, and their growth was found to be oriented with the axis of the aligned C60NWs. Cells grown on aligned C60NWs were more highly oriented with the axis of alignment than when grown on randomly oriented nanowhiskers. A study of cell proliferation on the C60NWs revealed their low toxicity, indicating their potential for use in biomedical applications. PMID:26115554

  4. Electrospinning of unidirectionally and orthogonally aligned thermoplastic polyurethane nanofibers: Fiber orientation and cell migration

    PubMed Central

    Mi, Hao-Yang; Salick, Max R.; Jing, Xin; Crone, Wendy C.; Peng, Xiang-Fang; Turng, Lih-Sheng

    2015-01-01

    Unidirectionally and orthogonally aligned thermoplastic polyurethane (TPU) nanofibers were electrospun using a custom-built electrospinning device. The unidirectionally aligned fibers were collected using two parallel copper plates, and the orthogonally aligned fibers were collected using two orthogonal sets of parallel copper plates with alternate negative connections. Carbon nanotubes (CNT) and polyacrylic acid (PAA) were added to modify the polymer solution. It was found that both CNT and PAA were capable of increasing solution conductivity. The TPU/PAA fiber showed the highest degree of fiber orientation with more than 90% of the fibers having an orientation angle between −10° and 10° for unidirectionally aligned fibers, and for orthogonally aligned fibers, the orientation angle of 50% fibers located between −10° and 10° and 48% fibers located between 80° and 100°. Viability assessment of 3T3 fibroblasts cultured on TPU/PAA fibers suggested that the material was cytocompatible. The cells’ orientation and migration direction closely matched the fibers’ orientation. The cell migration velocity and distance were both enhanced with the guidance of fibers compared with cells cultured on random fibers and common tissue culture plastic. Controlling cell migration velocity and directionality may provide ways to influence differentiation and gene expression and systems that would allow further exploration of wound repair and metastatic cell behavior. PMID:24771704

  5. Electrospinning of unidirectionally and orthogonally aligned thermoplastic polyurethane nanofibers: fiber orientation and cell migration.

    PubMed

    Mi, Hao-Yang; Salick, Max R; Jing, Xin; Crone, Wendy C; Peng, Xiang-Fang; Turng, Lih-Sheng

    2015-02-01

    Unidirectionally and orthogonally aligned thermoplastic polyurethane (TPU) nanofibers were electrospun using a custom-built electrospinning device. The unidirectionally aligned fibers were collected using two parallel copper plates, and the orthogonally aligned fibers were collected using two orthogonal sets of parallel copper plates with alternate negative connections. Carbon nanotubes (CNT) and polyacrylic acid (PAA) were added to modify the polymer solution. It was found that both CNT and PAA were capable of increasing solution conductivity. The TPU/PAA fiber showed the highest degree of fiber orientation with more than 90% of the fibers having an orientation angle between -10° and 10° for unidirectionally aligned fibers, and for orthogonally aligned fibers, the orientation angle of 50% fibers located between -10° and 10° and 48% fibers located between 80° and 100°. Viability assessment of 3T3 fibroblasts cultured on TPU/PAA fibers suggested that the material was cytocompatible. The cells' orientation and migration direction closely matched the fibers' orientation. The cell migration velocity and distance were both enhanced with the guidance of fibers compared with cells cultured on random fibers and common tissue culture plastic. Controlling cell migration velocity and directionality may provide ways to influence differentiation and gene expression and systems that would allow further exploration of wound repair and metastatic cell behavior. PMID:24771704

  6. Resonant optical alignment and orientation of Mn2+ spins in CdMnTe crystals

    NASA Astrophysics Data System (ADS)

    Baryshnikov, K. A.; Langer, L.; Akimov, I. A.; Korenev, V. L.; Kusrayev, Yu. G.; Averkiev, N. S.; Yakovlev, D. R.; Bayer, M.

    2015-11-01

    We report on spin orientation and alignment of Mn2 + ions in (Cd,Mn)Te diluted magnetic semiconductor crystals using resonant intracenter excitation with circular- and linear-polarized light. The resulting polarized emission of the magnetic ions is observed at low temperatures when the spin relaxation time of the Mn2 + ions is in the order of 1 ms , which considerably exceeds the photoluminescence decay time of 23 μ s . We demonstrate that the experimental data on optical orientation and alignment of Mn2 + ions can be explained using a phenomenological model that is based on the approximation of isolated centers.

  7. Oriented growth of rat Schwann cells on aligned electrospun poly(methyl methacrylate) nanofibers.

    PubMed

    Xia, Haijian; Sun, Xiaochuan; Liu, Dan; Zhou, Yudong; Zhong, Dong

    2016-10-15

    Transplanted Schwann cells have the potential to serve as a support for regenerating neurites after spinal cord injury. However, implanted Schwann cells die off rapidly once transplanted partly owing to the absence of a proper matrix support, with a glia scar and a cavity being present instead at the injury site. For this report, we evaluated aligned electrospun poly(methyl methacrylate) nanofibers as a Schwann cell-loading scaffold in vitro. By monitoring the fluorescence of green fluorescence protein-containing Schwann cells cultured on nanofibers, we found that aligned nanofibers provided better support for the cells than did non-aligned nanofibers. The cells elongated along the long axes of the aligned nanofibers and formed longer cell processes than when the substrate was non-aligned nanofibers. By coculturing Schwann cells with dorsal root ganglion neurons, it was also found that Schwann cells and neurites of dorsal root ganglion neurons could share and both elongate along the orientation of aligned nanofibers and thus they had a higher chance of colocalization than cocultured on film and non-aligned fibers, which might be beneficial to the ensuring process of myelination. The results of the study indicate that aligned electrospun nanofibers may serve as a Schwann cell-loading scaffold for future implantation research. PMID:27653871

  8. Mechanisms of liquid crystal and biopolymer alignment on highly-oriented polymer thin films

    NASA Astrophysics Data System (ADS)

    Dennis, John Raymond

    1998-12-01

    Molecular order can strongly enhance material properties, or produce materials which perform advanced functions. Many materials, from small crystals to large macromolecules, may be aligned on highly-oriented poly(tetrafluoroethylene) (PTFE) or high-density polyethylene (HDPE) thin films, prepared by a simple shear deposition procedure. Here, processes by which these films produce order are examined, first in a well- characterized liquid crystal, then in two more complex polymer liquid crystals, and finally in an adsorbed motor protein system. Optical second harmonic generation (SHG) was used to study surface molecular order in the liquid crystal 4'-n-octyl-4-cyano-biphenyl (8CB) on PTFE and HDPE films. In nematic 8CB cells with bulk alignment along the polymer orientation axis, the surface monolayers of 8CB were also aligned, and showed C2ν symmetry. In the isotropic phase, the surface monolayer alignment was lost. Monolayers of 8CB evaporated onto either polymer showed little or no alignment. The bulk 8CB alignment appears to be primarily caused by surface ridges through an elastic, bulk- mediated mechanism, unlike the epitaxy-like alignment found on some cloth-rubbed polymer surfaces. For the polymer liquid crystal poly-γ-benzyl- glutamate (PBG), uniform homogeneous surface alignment was observed on PTFE films; this is the first report of PBG surface alignment. However, liquid crystalline samples of microtubules were not aligned. PTFE films show promise for aligning some other polymer liquid crystals via elastic interactions. The motor protein kinesin, adsorbed to PTFE films, transported fluorescently labeled microtubules predominantly in straight lines along the films' orientation axis, not in random directions as observed on glass surfaces. As the kinesin surface density was increased, the degree of alignment peaked and then declined. The results indicate that directed motion occurs because active kinesin preferentially adsorbs to surface sites along linear

  9. Dead-zone-free atomic magnetometry with simultaneous excitation of orientation and alignment resonances.

    PubMed

    Ben-Kish, A; Romalis, M V

    2010-11-01

    Atomic magnetometers have very high absolute precision and sensitivity to magnetic fields but suffer from a fundamental problem: the vectorial or tensorial interaction of light with atoms leads to "dead zones," certain orientations of the magnetic field where the magnetometer loses its sensitivity. We demonstrate a simple polarization modulation scheme that simultaneously creates coherent population trapping (CPT) in orientation and alignment, thereby eliminating dead zones. Using 87Rb in a 10 Torr buffer gas cell we measure narrow, high-contrast CPT transparency peaks for all orientations and also show the absence of systematic effects associated with nonlinear Zeeman splitting.

  10. Dead-zone-free atomic magnetometry with simultaneous excitation of orientation and alignment resonances.

    PubMed

    Ben-Kish, A; Romalis, M V

    2010-11-01

    Atomic magnetometers have very high absolute precision and sensitivity to magnetic fields but suffer from a fundamental problem: the vectorial or tensorial interaction of light with atoms leads to "dead zones," certain orientations of the magnetic field where the magnetometer loses its sensitivity. We demonstrate a simple polarization modulation scheme that simultaneously creates coherent population trapping (CPT) in orientation and alignment, thereby eliminating dead zones. Using 87Rb in a 10 Torr buffer gas cell we measure narrow, high-contrast CPT transparency peaks for all orientations and also show the absence of systematic effects associated with nonlinear Zeeman splitting. PMID:21231166

  11. Anisotropic light absorption, refractive indices, and orientational order parameter of unidirectionally aligned columnar liquid crystal films.

    PubMed

    Charlet, Emilie; Grelet, Eric

    2008-10-01

    The anisotropic optical properties of thermotropic columnar liquid crystals absorbing in the visible range are investigated for different discotic compounds unidirectionally oriented in open supported thin films. Two methods to monitor the alignment of columnar mesophases in thin films are reported, making possible to achieve either homeotropic anchoring (columns normal to the substrate) by a specific thermal annealing, or unidirectional planar orientation (columns parallel to the substrate) by using a rubbed Teflon coating. The columnar liquid crystal anchoring is found to depend on the nature of the compound, either parallel or perpendicular to the Teflon orientation. Based on this control of the mesophase alignment, the dichroic ratio and the orientational order parameter of oriented samples are measured, and a high order parameter of 0.9 is found in the case of parallel alignment. From the polarized absorption data of the columnar liquid crystal films, the light wavelength dependence of the birefringence and of the real and imaginary parts (refractive index and extinction coefficient, respectively) of the anisotropic optical indices are determined over the whole visible range. PMID:18999445

  12. Guiding the orientation of smooth muscle cells on random and aligned polyurethane/collagen nanofibers.

    PubMed

    Jia, Lin; Prabhakaran, Molamma P; Qin, Xiaohong; Ramakrishna, Seeram

    2014-09-01

    Fabricating scaffolds that can simulate the architecture and functionality of native extracellular matrix is a huge challenge in vascular tissue engineering. Various kinds of materials are engineered via nano-technological approaches to meet the current challenges in vascular tissue regeneration. During this study, nanofibers from pure polyurethane and hybrid polyurethane/collagen in two different morphologies (random and aligned) and in three different ratios of polyurethane:collagen (75:25; 50:50; 25:75) are fabricated by electrospinning. The fiber diameters of the nanofibrous scaffolds are in the range of 174-453 nm and 145-419 for random and aligned fibers, respectively, where they closely mimic the nanoscale dimensions of native extracellular matrix. The aligned polyurethane/collagen nanofibers expressed anisotropic wettability with mechanical properties which is suitable for regeneration of the artery. After 12 days of human aortic smooth muscle cells culture on different scaffolds, the proliferation of smooth muscle cells on hybrid polyurethane/collagen (3:1) nanofibers was 173% and 212% higher than on pure polyurethane scaffolds for random and aligned scaffolds, respectively. The results of cell morphology and protein staining showed that the aligned polyurethane/collagen (3:1) scaffold promote smooth muscle cells alignment through contact guidance, while the random polyurethane/collagen (3:1) also guided cell orientation most probably due to the inherent biochemical composition. Our studies demonstrate the potential of aligned and random polyurethane/collagen (3:1) as promising substrates for vascular tissue regeneration.

  13. Mapping local orientation of aligned fibrous scatterers for cancerous tissues using backscattering Mueller matrix imaging

    NASA Astrophysics Data System (ADS)

    He, Honghui; Sun, Minghao; Zeng, Nan; Du, E.; Liu, Shaoxiong; Guo, Yihong; Wu, Jian; He, Yonghong; Ma, Hui

    2014-10-01

    Polarization measurements are sensitive to the microstructure of tissues and can be used to detect pathological changes. Many tissues contain anisotropic fibrous structures. We obtain the local orientation of aligned fibrous scatterers using different groups of the backscattering Mueller matrix elements. Experiments on concentrically well-aligned silk fibers and unstained human papillary thyroid carcinoma tissues show that the m22, m33, m23, and m32 elements have better contrast but higher degeneracy for the extraction of orientation angles. The m12 and m13 elements show lower contrast, but allow us to determine the orientation angle for the fibrous scatterers along all directions. Moreover, Monte Carlo simulations based on the sphere-cylinder scattering model indicate that the oblique incidence of the illumination beam introduces some errors in the orientation angles obtained by both methods. Mapping the local orientation of anisotropic tissues may not only provide information on pathological changes, but can also give new leads to reduce the orientation dependence of polarization measurements.

  14. Laser-Induced Alignment and Orientation of Quantum-State Large Molecules

    NASA Astrophysics Data System (ADS)

    Filsinger, Frank; Küpper, Jochen; Meijer, Gerard; Holmegaard, Lotte; Nielsen, Jens H.; Nevo, Iftach; Hansen, Jonas L.; Stapelfeldt, Henrik

    2009-06-01

    For many experiments in chemistry and physics, i. e., reactive scattering, X-ray or electron diffraction experiments, a high level of control over the spatial orientation of molecules would be very beneficial. It is well known that molecules can be aligned and oriented in space using strong dc electric fields or laser pulses. Here, we demonstrate that the degree of laser-induced alignment and orientation can be considerably improved, if quantum state selected samples are used. A strong inhomogeneous electric field is used in a Stern-Gerlach-type experiment to disperse iodobenzene molecules in a supersonic jet according to their rotational quantum state. Molecules in the lowest rotational quantum states are deflected most and can be used as targets for further experiments. This method is widely applicable to all, small and large, polar molecules and should eventually enable experiments on pure samples of strongly aligned or oriented ground-state molecules offering new prospects in molecular sciences. H. Stapelfeldt and T. Seideman, Rev. Mod. Phys., 75, (2003), 543 L. Holmegaard et al., Phys. Rev. Lett., 102, (2009), 023001

  15. Evaluation of Eight Methods for Aligning Orientation of Two Coordinate Systems.

    PubMed

    Mecheri, Hakim; Robert-Lachaine, Xavier; Larue, Christian; Plamondon, André

    2016-08-01

    The aim of this study was to evaluate eight methods for aligning the orientation of two different local coordinate systems. Alignment is very important when combining two different systems of motion analysis. Two of the methods were developed specifically for biomechanical studies, and because there have been at least three decades of algorithm development in robotics, it was decided to include six methods from this field. To compare these methods, an Xsens sensor and two Optotrak clusters were attached to a Plexiglas plate. The first optical marker cluster was fixed on the sensor and 20 trials were recorded. The error of alignment was calculated for each trial, and the mean, the standard deviation, and the maximum values of this error over all trials were reported. One-way repeated measures analysis of variance revealed that the alignment error differed significantly across the eight methods. Post-hoc tests showed that the alignment error from the methods based on angular velocities was significantly lower than for the other methods. The method using angular velocities performed the best, with an average error of 0.17 ± 0.08 deg. We therefore recommend this method, which is easy to perform and provides accurate alignment. PMID:27245737

  16. Aligned platinum nanowire networks from surface-oriented lipid cubic phase templates

    NASA Astrophysics Data System (ADS)

    Richardson, S. J.; Burton, M. R.; Staniec, P. A.; Nandhakumar, I. S.; Terrill, N. J.; Elliott, J. M.; Squires, A. M.

    2016-01-01

    Mesoporous metal structures featuring a bicontinuous cubic morphology have a wide range of potential applications and novel opto-electronic properties, often orientation-dependent. We describe the production of nanostructured metal films 1-2 microns thick featuring 3D-periodic `single diamond' morphology that show high out-of-plane alignment, with the (111) plane oriented parallel to the substrate. These are produced by electrodeposition of platinum through a lipid cubic phase (QII) template. Further investigation into the mechanism for the orientation revealed the surprising result that the QII template, which is tens of microns thick, is polydomain with no overall orientation. When thicker platinum films are grown, they also show increased orientational disorder. These results suggest that polydomain QII samples display a region of uniaxial orientation at the lipid/substrate interface up to approximately 2.8 +/- 0.3 μm away from the solid surface. Our approach gives previously unavailable information on the arrangement of cubic phases at solid interfaces, which is important for many applications of QII phases. Most significantly, we have produced a previously unreported class of oriented nanomaterial, with potential applications including metamaterials and lithographic masks.Mesoporous metal structures featuring a bicontinuous cubic morphology have a wide range of potential applications and novel opto-electronic properties, often orientation-dependent. We describe the production of nanostructured metal films 1-2 microns thick featuring 3D-periodic `single diamond' morphology that show high out-of-plane alignment, with the (111) plane oriented parallel to the substrate. These are produced by electrodeposition of platinum through a lipid cubic phase (QII) template. Further investigation into the mechanism for the orientation revealed the surprising result that the QII template, which is tens of microns thick, is polydomain with no overall orientation. When thicker

  17. Alignment of crystal orientations of the multi-domain photonic crystals in Parides sesostris wing scales.

    PubMed

    Yoshioka, S; Fujita, H; Kinoshita, S; Matsuhana, B

    2014-03-01

    It is known that the wing scales of the emerald-patched cattleheart butterfly, Parides sesostris, contain gyroid-type photonic crystals, which produce a green structural colour. However, the photonic crystal is not a single crystal that spreads over the entire scale, but it is separated into many small domains with different crystal orientations. As a photonic crystal generally has band gaps at different frequencies depending on the direction of light propagation, it seems mysterious that the scale is observed to be uniformly green under an optical microscope despite the multi-domain structure. In this study, we have carefully investigated the structure of the wing scale and discovered that the crystal orientations of different domains are not perfectly random, but there is a preferred crystal orientation that is aligned along the surface normal of the scale. This finding suggests that there is an additional factor during the developmental process of the microstructure that regulates the crystal orientation. PMID:24352678

  18. Tubular Hydrogels of Circumferentially Aligned Nanofibers to Encapsulate and Orient Vascular Cells

    PubMed Central

    McClendon, Mark T.; Stupp, Samuel I.

    2012-01-01

    There is a great clinical need for tissue engineered blood vessels that could be used to replace or bypass damaged arteries. The success of such grafts will depend strongly on their ability to mimic the cellular and matrix organization found in native arteries, but currently available cell scaffolds such as electrospun fibers or hydrogels lack the ability to simultaneously encapsulate and align cells. Our laboratory has recently developed liquid crystalline solutions of peptide amphiphile nanofibers that form aligned domains at exceedingly low concentrations (<1wt%), and can be trapped as gels with macroscopic alignment using low shear rates and ionic crosslinking. We describe here the use of these systems to fabricate tubes with macroscopic circumferential alignment and demonstrate their potential as arterial cell scaffolds. The nanofibers in these tubes were circumferentially aligned by applying small amounts of shear in a custom built flow chamber prior to gelation. Small angle X-ray scattering confirmed that the direction of nanofiber alignment was the same as the direction of shear flow. We also show the encapsulation of smooth muscle cells during the fabrication process without compromising cell viability. After two days in culture the encapsulated cells oriented their long axis in the direction of nanofiber alignment thus mimicking the circumferential alignment seen in native arteries. Cell density roughly doubled after 12 days demonstrating the scaffold’s ability to facilitate necessary graft maturation. Since these nanofiber gels are composed of >99% water by weight, the cells have abundant room for proliferation and remodeling. In contrast to previously reported arterial cell scaffolds, this new material can encapsulate cells and direct cellular organization without the requirement of external stimuli or gel compaction. PMID:22591610

  19. Object oriented software for simulation and reconstruction of big alignment systems

    NASA Astrophysics Data System (ADS)

    Arce, P.

    2003-04-01

    Modern high-energy physics experiments require tracking detectors to provide high precision under difficult working conditions (high magnetic field, gravity loads and temperature gradients). This is the reason why several of them are deciding to implement optical alignment systems to monitor the displacement of tracking elements in operation. To simulate and reconstruct optical alignment systems a general purpose software, named COCOA, has been developed, using the object oriented paradigm and software engineering techniques. Thanks to the big flexibility in its design, COCOA is able to reconstruct any optical system made of a combination of the following objects: laser, x-hair laser, incoherent source—pinhole, lens, mirror, plate splitter, cube splitter, optical square, rhomboid prism, 2D sensor, 1D sensor, distance-meter, tilt-meter, user-defined. COCOA was designed to satisfy the requirements of the CMS alignment system, which has several thousands of components. Sparse matrix techniques had been investigated for solving non-linear least squares fits with such a big number of parameters. The soundness of COCOA has already been stressed in the reconstruction of the data of a full simulation of a quarter plane of the CMS muon alignment system, which implied solving a system of 900 equations with 850 unknown parameters. Full simulation of the whole CMS alignment system, with over 30,000 parameters, is quite advanced. The integration of COCOA in the CMS software framework is also under progress.

  20. Guiding the orientation of smooth muscle cells on random and aligned polyurethane/collagen nanofibers.

    PubMed

    Jia, Lin; Prabhakaran, Molamma P; Qin, Xiaohong; Ramakrishna, Seeram

    2014-09-01

    Fabricating scaffolds that can simulate the architecture and functionality of native extracellular matrix is a huge challenge in vascular tissue engineering. Various kinds of materials are engineered via nano-technological approaches to meet the current challenges in vascular tissue regeneration. During this study, nanofibers from pure polyurethane and hybrid polyurethane/collagen in two different morphologies (random and aligned) and in three different ratios of polyurethane:collagen (75:25; 50:50; 25:75) are fabricated by electrospinning. The fiber diameters of the nanofibrous scaffolds are in the range of 174-453 nm and 145-419 for random and aligned fibers, respectively, where they closely mimic the nanoscale dimensions of native extracellular matrix. The aligned polyurethane/collagen nanofibers expressed anisotropic wettability with mechanical properties which is suitable for regeneration of the artery. After 12 days of human aortic smooth muscle cells culture on different scaffolds, the proliferation of smooth muscle cells on hybrid polyurethane/collagen (3:1) nanofibers was 173% and 212% higher than on pure polyurethane scaffolds for random and aligned scaffolds, respectively. The results of cell morphology and protein staining showed that the aligned polyurethane/collagen (3:1) scaffold promote smooth muscle cells alignment through contact guidance, while the random polyurethane/collagen (3:1) also guided cell orientation most probably due to the inherent biochemical composition. Our studies demonstrate the potential of aligned and random polyurethane/collagen (3:1) as promising substrates for vascular tissue regeneration. PMID:24682037

  1. Lineation-parallel c-axis Fabric of Quartz Formed Under Water-rich Conditions

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Zhang, J.; Li, P.

    2014-12-01

    The crystallographic preferred orientation (CPO) of quartz is of great significance because it records much valuable information pertinent to the deformation of quartz-rich rocks in the continental crust. The lineation-parallel c-axis CPO (i.e., c-axis forming a maximum parallel to the lineation) in naturally deformed quartz is generally considered to form under high temperature (> ~550 ºC) conditions. However, most laboratory deformation experiments on quartzite failed to produce such a CPO at high temperatures up to 1200 ºC. Here we reported a new occurrence of the lineation-parallel c-axis CPO of quartz from kyanite-quartz veins in eclogite. Optical microstructural observations, fourier transform infrared (FTIR) and electron backscattered diffraction (EBSD) techniques were integrated to illuminate the nature of quartz CPOs. Quartz exhibits mostly straight to slightly curved grain boundaries, modest intracrystalline plasticity, and significant shape preferred orientation (SPO) and CPOs, indicating dislocation creep dominated the deformation of quartz. Kyanite grains in the veins are mostly strain-free, suggestive of their higher strength than quartz. The pronounced SPO and CPOs in kyanite were interpreted to originate from anisotropic crystal growth and/or mechanical rotation during vein-parallel shearing. FTIR results show quartz contains a trivial amount of structurally bound water (several tens of H/106 Si), while kyanite has a water content of 384-729 H/106 Si; however, petrographic observations suggest quartz from the veins were practically deformed under water-rich conditions. We argue that the observed lineation-parallel c-axis fabric in quartz was inherited from preexisting CPOs as a result of anisotropic grain growth under stress facilitated by water, but rather than due to a dominant c-slip. The preservation of the quartz CPOs probably benefited from the preexisting quartz CPOs which renders most quartz grains unsuitably oriented for an easy a-slip at

  2. Pulsed laser deposition of c-axis untilted YBCO films on c-axis tilted ISD MgO-buffered metallic substrates

    NASA Astrophysics Data System (ADS)

    Li, M.; Ma, B.; Koritala, R. E.; Fisher, B. L.; Venkataraman, K.; Maroni, V. A.; Vlasko-Vlasov, V.; Berghuis, P.; Welp, U.; Gray, K. E.; Balachandran, U.

    2003-05-01

    Biaxially textured MgO template layer was deposited on nontextured metal substrates by inclined-substrate deposition (ISD) at a deposition rate of 24-600 nm/min. c-axis untilted YBa 2Cu 3O 7- x (YBCO) films were deposited on these MgO-buffered substrates by pulsed laser deposition. The crystalline structures of the YBCO films and MgO layers were examined by X-ray pole figure analysis, X-ray φ-scans, and χ-scans. A tilt angle of 33° of the MgO[0 0 1] with respect to the substrate normal and c-axis untilted YBCO films were observed, respectively. Good biaxial texture of these films with full-width-at-half-maximum values of 13.8° and 10.6° for the φ-scans of YBCO(1 0 3) and MgO(2 2 0), respectively, were obtained. Morphologies were examined by scanning electron microscopy, which revealed a unique roof-tile feature and columnar grain growth for the ISD MgO layer. Raman spectroscopy and magneto-optical image technique were also used to evaluate the quality of the YBCO film. An angular dependence of Jc on the direction of an applied magnetic field confirmed the c-axis untilted orientation of the YBCO films. Tc=90 K with sharp transition and Jc=3.0×10 5 A/cm 2 at 77 K in zero field were obtained on 0.4-μm-thick YBCO films.

  3. Photoreactive self-assembled monolayer for the stabilization of tilt orientation of a director in vertically aligned nematic liquid crystals.

    PubMed

    Oh, Su Yeon; Kang, Shin-Woong

    2013-12-16

    Photo-reactive self-assembled monolayer (PR-SAM) is employed to mediate alignment of liquid crystals (LC) and stabilize the tilt orientation of a nematic director for a vertically aligned liquid crystal. Bifunctional PR-SAM formed by silane coupling reaction to oxide surfaces efficiently induces a homeotropic alignment and stabilizes LC director by the photo-polymerization under applied electric field. As a result, the substantial enhancement of electro-optic performance has been achieved after the PR-SAM assisted stabilization of tilt orientation of director. This approach for pretilt stabilization has multifarious advantages over the conventional PSVA. PMID:24514711

  4. Nanofiber Alignment Regulates NIH3T3 Cell Orientation and Cytoskeletal Gene Expression on Electrospun PCL+Gelatin Nanofibers

    PubMed Central

    Fee, Timothy; Surianarayanan, Swetha; Downs, Crawford; Zhou, Yong; Berry, Joel

    2016-01-01

    To examine the influence of substrate topology on the behavior of fibroblasts, tissue engineering scaffolds were electrospun from polycaprolactone (PCL) and a blend of PCL and gelatin (PCL+Gel) to produce matrices with both random and aligned nanofibrous orientations. The addition of gelatin to the scaffold was shown to increase the hydrophilicity of the PCL matrix and to increase the proliferation of NIH3T3 cells compared to scaffolds of PCL alone. The orientation of nanofibers within the matrix did not have an effect on the proliferation of adherent cells, but cells on aligned substrates were shown to elongate and align parallel to the direction of substrate fiber alignment. A microarray of cyotoskeleton regulators was probed to examine differences in gene expression between cells grown on an aligned and randomly oriented substrates. It was found that transcriptional expression of eight genes was statistically different between the two conditions, with all of them being upregulated in the aligned condition. The proteins encoded by these genes are linked to production and polymerization of actin microfilaments, as well as focal adhesion assembly. Taken together, the data indicates NIH3T3 fibroblasts on aligned substrates align themselves parallel with their substrate and increase production of actin and focal adhesion related genes. PMID:27196306

  5. Orientation variation of dayside auroral arc alignments obtained from all-sky observation at yellow river station, Svalbard

    NASA Astrophysics Data System (ADS)

    Qiu, Qi; Yang, Hui-Gen; Lu, Quan-Ming; Hu, Ze-Jun; Han, De-Sheng; Wang, Qian

    2016-05-01

    The orientations of dayside auroral arc alignments were calculated for over 40,000 images from all-sky observation at Yellow River Station, Svalbard. For each arc, its "orientation" and "tilt" are defined as the angle the arc alignment makes with the dusk-dawn direction and the local east-west direction, respectively. The mean arc orientation increases linearly with the increasing magnetic local time (MLT). There is a reversal point of the arc tilt located at near 10.5 MLT. Compared with the mean orientation, auroral arc alignment tilts to morning side in the higher latitude and tilts to evening side in the lower latitude in the prenoon sector, whereas it is the opposite in the postnoon sector. We further studied the effects of the interplanetary magnetic field (IMF) on the location of the arc tilt reversal point. We found that the reversal position shifts toward the midday for negative By.

  6. Distinct modes of mitotic spindle orientation align cells in the dorsal midline of ascidian embryos.

    PubMed

    Negishi, Takefumi; Yasuo, Hitoyoshi

    2015-12-01

    The orientation of cell division can have important consequences on the choice of cell fates adopted by each daughter cell as well as on the architecture of the tissue within which the dividing cell resides. We have studied in detail the oriented cell divisions that take place in the dorsal midline of the ascidian embryo. The dorsal midline cells of the ascidian embryo emerge following an asymmetric cell division oriented along the animal-vegetal (A-V) axis. This division generates the NN (Notochord-Neural) cell at the margin and the E (Endoderm) cell more vegetally. Deviating from the default mode of cell division, these sister cells divide again along the A-V axis to generate a column of four cells. We describe these cell divisions in detail. We show that the NN cell mitotic spindle rotates 90° to align along the A-V axis while the E cell spindle forms directly along the axis following the asymmetric migration of its centrosomes. We combine live imaging, embryo manipulations and pharmacological modulation of cytoskeletal elements to address the mechanisms underlying these distinct subcellular behaviours. Our evidence suggests that, in E cells, aster asymmetry together with the E cell shape contribute to the asymmetric centrosome migration. In NN cells, an intrinsic cytoplasmic polarisation of the cell results in the accumulation of dynein to the animal pole side. Our data support a model in which a dynein-dependent directional cytoplasmic pulling force may be responsible for the NN cell spindle rotation. PMID:26452428

  7. Distinct modes of mitotic spindle orientation align cells in the dorsal midline of ascidian embryos.

    PubMed

    Negishi, Takefumi; Yasuo, Hitoyoshi

    2015-12-01

    The orientation of cell division can have important consequences on the choice of cell fates adopted by each daughter cell as well as on the architecture of the tissue within which the dividing cell resides. We have studied in detail the oriented cell divisions that take place in the dorsal midline of the ascidian embryo. The dorsal midline cells of the ascidian embryo emerge following an asymmetric cell division oriented along the animal-vegetal (A-V) axis. This division generates the NN (Notochord-Neural) cell at the margin and the E (Endoderm) cell more vegetally. Deviating from the default mode of cell division, these sister cells divide again along the A-V axis to generate a column of four cells. We describe these cell divisions in detail. We show that the NN cell mitotic spindle rotates 90° to align along the A-V axis while the E cell spindle forms directly along the axis following the asymmetric migration of its centrosomes. We combine live imaging, embryo manipulations and pharmacological modulation of cytoskeletal elements to address the mechanisms underlying these distinct subcellular behaviours. Our evidence suggests that, in E cells, aster asymmetry together with the E cell shape contribute to the asymmetric centrosome migration. In NN cells, an intrinsic cytoplasmic polarisation of the cell results in the accumulation of dynein to the animal pole side. Our data support a model in which a dynein-dependent directional cytoplasmic pulling force may be responsible for the NN cell spindle rotation.

  8. Autoionization Resonances in Orientation and Alignment Parameters for Excited Ions after Electron Impact Ionization.

    NASA Astrophysics Data System (ADS)

    Balashov, Vselovod; Bartschat, Klaus; Marchalant, Pascale

    1997-04-01

    We have extended previous work for alignment and orientation parameters in simultaneous ionization-excitation [1] to include the effect of autoionizing resonances. The expected effect is similar to that suggested for photoionization via autoionizing states [2]. Special emphasis is given to the process e + He --> e_scattered+e_ejected +He^+(2p), followed by He^+(2p) --> He^+(1s) + γ where the scattered electron and the emitted photon are detected in coincidence. 1. R. Schwienhorst, A. Raeker, K. Bartschat and K. Blum (1996), 1. J. Phys. B 29, 2305 2. V.V. Balashov, N.M. Kabachnik and V.S. Senashenko (1983), 2. Book of Abstracts ICPEAC XIII, 23 permanent address: Moscow State University

  9. Non-adiabatic effects in near-adiabatic mixed-field orientation and alignment

    NASA Astrophysics Data System (ADS)

    Maan, Anjali; Ahlawat, Dharamvir Singh; Prasad, Vinod

    2016-11-01

    We present a theoretical study of the impact of a pair of moderate electric fields tilted an angle with respect to one another on a molecule. As a prototype, we consider a molecule with large rotational constant (with corresponding small rotational period) and moderate dipole moment. Within rigid-rotor approximation, the time-dependent Schrodinger equation is solved using fourth-order Runge-Kutta method. We have analysed that lower rotational states are significantly influenced by variation in pulse durations, the tilt angle between the fields and also on the electric field strengths. We also suggest a control scheme of how the rotational dynamics, orientation and alignment of a molecule can be enhanced by a combination of near-adiabatic pulses in comparision to non-adiabatic or adiabatic pulses.

  10. Crystal alignments in the fast ice of Arctic Alaska

    SciTech Connect

    Weeks, W.F.; Gow, A.J.

    1980-02-20

    Field observations at 60 sites located in the fast or near-fast ice along a 1200-km stretch of the north coast of Alaska between the Bering Strait and Barter Island have shown that the great majority of the ice samples (95%) exhibit striking c axis alignments within the horizontal plane. In all cases the degree of preferred orientation increased with depth in the ice. Representative standard deviations around a mean direction in the horizontal plane are commonly less than +- 10/sup 0/ for samples collected near the bottom of the ice. At a given site the mean c axis direction X-bar/sub 0/ may vary as much as 20/sup 0/ with vertical location in the ice sheet. The c axis allignments in the nearshore region generally parallel the coast, with strong alignments occurring in the lagoon systems between the barrier islands and the coast and seaward of the barrier islands. In passes between islands and in entrances such as the opening to Kotzebue Sound the alignment is parallel to the channel. Only limited observations are available farther seaward over the inner (10- to 50-m isobaths) and outer (50-m isobath to shelf break) shelf regions. These indicate Ne-SW and E-W alignments, respectively, in the Beaufort Sea north of Prudhoe Bay.

  11. Growth of Well-Aligned InN Nanorods on Amorphous Glass Substrates.

    PubMed

    Li, Huijie; Zhao, Guijuan; Wei, Hongyuan; Wang, Lianshan; Chen, Zhen; Yang, Shaoyan

    2016-12-01

    The growth of well-aligned nanorods on amorphous substrates can pave the way to fabricate large-scale and low-cost devices. In this work, we successfully prepared vertically well-aligned c-axis InN nanorods on amorphous glass substrate by metal-organic chemical vapor deposition. The products formed directly on bare glass are randomly oriented without preferential growth direction. By inserting a GaN/Ti interlayer, the nanowire alignment can be greatly improved as indicated by scanning electron microscopy and X-ray diffraction. PMID:27229517

  12. Correlation between micrometer-scale ripple alignment and atomic-scale crystallographic orientation of monolayer graphene.

    PubMed

    Choi, Jin Sik; Chang, Young Jun; Woo, Sungjong; Son, Young-Woo; Park, Yeonggu; Lee, Mi Jung; Byun, Ik-Su; Kim, Jin-Soo; Choi, Choon-Gi; Bostwick, Aaron; Rotenberg, Eli; Park, Bae Ho

    2014-01-01

    Deformation normal to the surface is intrinsic in two-dimensional materials due to phononic thermal fluctuations at finite temperatures. Graphene's negative thermal expansion coefficient is generally explained by such an intrinsic property. Recently, friction measurements on graphene exfoliated on a silicon oxide surface revealed an anomalous anisotropy whose origin was believed to be the formation of ripple domains. Here, we uncover the atomistic origin of the observed friction domains using a cantilever torsion microscopy in conjunction with angle-resolved photoemission spectroscopy. We experimentally demonstrate that ripples on graphene are formed along the zigzag direction of the hexagonal lattice. The formation of zigzag directional ripple is consistent with our theoretical model that takes account of the atomic-scale bending stiffness of carbon-carbon bonds and the interaction of graphene with the substrate. The correlation between micrometer-scale ripple alignment and atomic-scale arrangement of exfoliated monolayer graphene is first discovered and suggests a practical tool for measuring lattice orientation of graphene. PMID:25434431

  13. Correlation between micrometer-scale ripple alignment and atomic-scale crystallographic orientation of monolayer graphene

    NASA Astrophysics Data System (ADS)

    Choi, Jin Sik; Chang, Young Jun; Woo, Sungjong; Son, Young-Woo; Park, Yeonggu; Lee, Mi Jung; Byun, Ik-Su; Kim, Jin-Soo; Choi, Choon-Gi; Bostwick, Aaron; Rotenberg, Eli; Park, Bae Ho

    2014-12-01

    Deformation normal to the surface is intrinsic in two-dimensional materials due to phononic thermal fluctuations at finite temperatures. Graphene's negative thermal expansion coefficient is generally explained by such an intrinsic property. Recently, friction measurements on graphene exfoliated on a silicon oxide surface revealed an anomalous anisotropy whose origin was believed to be the formation of ripple domains. Here, we uncover the atomistic origin of the observed friction domains using a cantilever torsion microscopy in conjunction with angle-resolved photoemission spectroscopy. We experimentally demonstrate that ripples on graphene are formed along the zigzag direction of the hexagonal lattice. The formation of zigzag directional ripple is consistent with our theoretical model that takes account of the atomic-scale bending stiffness of carbon-carbon bonds and the interaction of graphene with the substrate. The correlation between micrometer-scale ripple alignment and atomic-scale arrangement of exfoliated monolayer graphene is first discovered and suggests a practical tool for measuring lattice orientation of graphene.

  14. Correlation between micrometer-scale ripple alignment and atomic-scale crystallographic orientation of monolayer graphene

    DOE PAGES

    Choi, Jin Sik; Chang, Young Jun; Woo, Sungjong; Son, Young-Woo; Park, Yeonggu; Lee, Mi Jung; Byun, Ik-Su; Kim, Jin-Soo; Choi, Choon-Gi; Bostwick, Aaron; et al

    2014-12-01

    Deformation normal to the surface is intrinsic in two-dimensional materials due to phononic thermal fluctuations at finite temperatures. Graphene's negative thermal expansion coefficient is generally explained by such an intrinsic property. Recently, friction measurements on graphene exfoliated on a silicon oxide surface revealed an anomalous anisotropy whose origin was believed to be the formation of ripple domains. Here, we uncover the atomistic origin of the observed friction domains using a cantilever torsion microscopy in conjunction with angle-resolved photoemission spectroscopy. We experimentally demonstrate that ripples on graphene are formed along the zigzag direction of the hexagonal lattice. The formation of zigzagmore » directional ripple is consistent with our theoretical model that takes account of the atomic-scale bending stiffness of carbon-carbon bonds and the interaction of graphene with the substrate. Lastly, the correlation between micrometer-scale ripple alignment and atomic-scale arrangement of exfoliated monolayer graphene is first discovered and suggests a practical tool for measuring lattice orientation of graphene.« less

  15. Correlation between micrometer-scale ripple alignment and atomic-scale crystallographic orientation of monolayer graphene

    PubMed Central

    Choi, Jin Sik; Chang, Young Jun; Woo, Sungjong; Son, Young-Woo; Park, Yeonggu; Lee, Mi Jung; Byun, Ik-Su; Kim, Jin-Soo; Choi, Choon-Gi; Bostwick, Aaron; Rotenberg, Eli; Park, Bae Ho

    2014-01-01

    Deformation normal to the surface is intrinsic in two-dimensional materials due to phononic thermal fluctuations at finite temperatures. Graphene's negative thermal expansion coefficient is generally explained by such an intrinsic property. Recently, friction measurements on graphene exfoliated on a silicon oxide surface revealed an anomalous anisotropy whose origin was believed to be the formation of ripple domains. Here, we uncover the atomistic origin of the observed friction domains using a cantilever torsion microscopy in conjunction with angle-resolved photoemission spectroscopy. We experimentally demonstrate that ripples on graphene are formed along the zigzag direction of the hexagonal lattice. The formation of zigzag directional ripple is consistent with our theoretical model that takes account of the atomic-scale bending stiffness of carbon-carbon bonds and the interaction of graphene with the substrate. The correlation between micrometer-scale ripple alignment and atomic-scale arrangement of exfoliated monolayer graphene is first discovered and suggests a practical tool for measuring lattice orientation of graphene. PMID:25434431

  16. Correlation between micrometer-scale ripple alignment and atomic-scale crystallographic orientation of monolayer graphene

    SciTech Connect

    Choi, Jin Sik; Chang, Young Jun; Woo, Sungjong; Son, Young-Woo; Park, Yeonggu; Lee, Mi Jung; Byun, Ik-Su; Kim, Jin-Soo; Choi, Choon-Gi; Bostwick, Aaron; Rotenberg, Eli; Park, Bae Ho

    2014-12-01

    Deformation normal to the surface is intrinsic in two-dimensional materials due to phononic thermal fluctuations at finite temperatures. Graphene's negative thermal expansion coefficient is generally explained by such an intrinsic property. Recently, friction measurements on graphene exfoliated on a silicon oxide surface revealed an anomalous anisotropy whose origin was believed to be the formation of ripple domains. Here, we uncover the atomistic origin of the observed friction domains using a cantilever torsion microscopy in conjunction with angle-resolved photoemission spectroscopy. We experimentally demonstrate that ripples on graphene are formed along the zigzag direction of the hexagonal lattice. The formation of zigzag directional ripple is consistent with our theoretical model that takes account of the atomic-scale bending stiffness of carbon-carbon bonds and the interaction of graphene with the substrate. Lastly, the correlation between micrometer-scale ripple alignment and atomic-scale arrangement of exfoliated monolayer graphene is first discovered and suggests a practical tool for measuring lattice orientation of graphene.

  17. Images of interlayer vortices and c -axis penetration depth of high- Tc YBa2Cu3O7-y superconductor

    NASA Astrophysics Data System (ADS)

    Iguchi, Ienari; Takeda, Tomohiro; Uchiyama, Tetsuji; Sugimoto, Akira; Hatano, Takeshi

    2006-06-01

    The measurements on the magnetic image of interlayer vortices are performed for the high- Tc YBa2Cu3O7-y(110) thin film using a high sensitive scanning SQUID microscopy. Clear images of aligned giant interlayer vortices are observable. For the majority of vortices, using the London model, the c -axis penetration depth is estimated to be about 20μm at 3K . The temperature dependence of λc is obtained from the observed vortex images at different temperatures, whose behavior is in good agreement with those of the microwave cavity measurement.

  18. Perfect alignment and preferential orientation of nitrogen-vacancy centers during chemical vapor deposition diamond growth on (111) surfaces

    SciTech Connect

    Michl, Julia; Zaiser, Sebastian; Jakobi, Ingmar; Waldherr, Gerald; Dolde, Florian; Neumann, Philipp Wrachtrup, Jörg; Teraji, Tokuyuki; Doherty, Marcus W.; Manson, Neil B.; Isoya, Junichi

    2014-03-10

    Synthetic diamond production is a key to the development of quantum metrology and quantum information applications of diamond. The major quantum sensor and qubit candidate in diamond is the nitrogen-vacancy (NV) color center. This lattice defect comes in four different crystallographic orientations leading to an intrinsic inhomogeneity among NV centers, which is undesirable in some applications. Here, we report a microwave plasma-assisted chemical vapor deposition diamond growth technique on (111)-oriented substrates, which yields perfect alignment (94% ± 2%) of as-grown NV centers along a single crystallographic direction. In addition, clear evidence is found that the majority (74% ± 4%) of the aligned NV centers were formed by the nitrogen being first included in the (111) growth surface and then followed by the formation of a neighboring vacancy on top. The achieved homogeneity of the grown NV centers will tremendously benefit quantum information and metrology applications.

  19. Phonon mean free path of graphite along the c-axis

    SciTech Connect

    Wei, Zhiyong; Yang, Juekuan; Chen, Weiyu; Bi, Kedong; Chen, Yunfei

    2014-02-24

    Phonon transport in the c-axis direction of graphite thin films has been studied using non-equilibrium molecular dynamics (MD) simulation. The simulation results show that the c-axis thermal conductivities for films of thickness ranging from 20 to 500 atomic layers are significantly lower than the bulk value. Based on the MD data, a method is developed to construct the c-axis thermal conductivity as an accumulation function of phonon mean free path (MFP), from which we show that phonons with MFPs from 2 to 2000 nm contribute ∼80% of the graphite c-axis thermal conductivity at room temperature, and phonons with MFPs larger than 100 nm contribute over 40% to the c-axis thermal conductivity. These findings indicate that the commonly believed value of just a few nanometers from the simple kinetic theory drastically underestimates the c-axis phonon MFP of graphite.

  20. Temperature-Dependent Mean Free Path Spectra of Thermal Phonons Along the c-Axis of Graphite.

    PubMed

    Zhang, Hang; Chen, Xiangwen; Jho, Young-Dahl; Minnich, Austin J

    2016-03-01

    Heat conduction in graphite has been studied for decades because of its exceptionally large thermal anisotropy. While the bulk thermal conductivities along the in-plane and cross-plane directions are well-known, less understood are the microscopic properties of the thermal phonons responsible for heat conduction. In particular, recent experimental and computational works indicate that the average phonon mean free path (MFP) along the c-axis is considerably larger than that estimated by kinetic theory, but the distribution of MFPs remains unknown. Here, we report the first quantitative measurements of c-axis phonon MFP spectra in graphite at a variety of temperatures using time-domain thermoreflectance measurements of graphite flakes with variable thickness. Our results indicate that c-axis phonon MFPs have values of a few hundred nanometers at room temperature and a much narrower distribution than in isotropic crystals. At low temperatures, phonon scattering is dominated by grain boundaries separating crystalline regions of different rotational orientation. Our study provides important new insights into heat transport and phonon scattering mechanisms in graphite and other anisotropic van der Waals solids.

  1. Temperature-Dependent Mean Free Path Spectra of Thermal Phonons Along the c-Axis of Graphite.

    PubMed

    Zhang, Hang; Chen, Xiangwen; Jho, Young-Dahl; Minnich, Austin J

    2016-03-01

    Heat conduction in graphite has been studied for decades because of its exceptionally large thermal anisotropy. While the bulk thermal conductivities along the in-plane and cross-plane directions are well-known, less understood are the microscopic properties of the thermal phonons responsible for heat conduction. In particular, recent experimental and computational works indicate that the average phonon mean free path (MFP) along the c-axis is considerably larger than that estimated by kinetic theory, but the distribution of MFPs remains unknown. Here, we report the first quantitative measurements of c-axis phonon MFP spectra in graphite at a variety of temperatures using time-domain thermoreflectance measurements of graphite flakes with variable thickness. Our results indicate that c-axis phonon MFPs have values of a few hundred nanometers at room temperature and a much narrower distribution than in isotropic crystals. At low temperatures, phonon scattering is dominated by grain boundaries separating crystalline regions of different rotational orientation. Our study provides important new insights into heat transport and phonon scattering mechanisms in graphite and other anisotropic van der Waals solids. PMID:26840052

  2. Conductivity sum rule, implication for in-plane dynamics, and c-axis response

    NASA Astrophysics Data System (ADS)

    Kim, Wonkee; Carbotte, J. P.

    2000-10-01

    Recently observed c-axis optical sum rule violations indicate non-Fermi-liquid in-plane behavior. For coherent c-axis coupling, the observed flat, nearly frequency-independent c-axis conductivity σ1(ω) implies a large in-plane scattering rate Γ around (0,π) and therefore any pseudogap that might form at low frequency in the normal state will be smeared. On the other hand, incoherent c-axis coupling places no restriction on the value of Γ and gives a more consistent picture of the observed sum-rule violation which, we find in some cases, can be less than half.

  3. Boundary conditions for fluids with internal orientational degrees of freedom: Apparent velocity slip associated with the molecular alignment

    SciTech Connect

    Heidenreich, Sebastian; Hess, Siegfried; Ilg, Patrick

    2007-06-15

    Boundary effects are investigated for fluids with internal orientational degrees of freedom such as molecular liquids, thermotropic and lyotropic liquid crystals, and polymeric fluids. The orientational degrees of freedom are described by the second rank alignment tensor which is related to the birefringence. We use a standard model to describe the orientational dynamics in the presence of flow, the momentum balance equations, and a constitutive law for the pressure tensor to describe our system. In the spirit of irreversible thermodynamics, boundary conditions are formulated for the mechanical slip velocity and the flux of the alignment. They are set up such that the entropy production at the wall inferred from the entropy flux is positive definite. Even in the absence of a true mechanical slip, the coupling between orientation and flow leads to flow profiles with an apparent slip. This has consequences for the macroscopically measurable effective velocity. In analytical investigations, we consider the simplified case of an isotropic fluid in the Newtonian and stationary flow regime. For special geometries such as plane and cylindrical Couette flow, plane Poiseuille flow, and a flow down an inclined plane, we demonstrate explicitly how the boundary conditions lead to an apparent slip. Furthermore, we discuss the dependence of the effective viscosity and of the effective slip length on the model parameters.

  4. Human airway smooth muscle maintain in situ cell orientation and phenotype when cultured on aligned electrospun scaffolds

    PubMed Central

    Morris, G. E.; Bridge, J. C.; Eltboli, O. M. I.; Lewis, M. P.; Knox, A. J.; Aylott, J. W.; Brightling, C. E.; Ghaemmaghami, A. M.

    2014-01-01

    Human airway smooth muscle (HASM) contraction plays a central role in regulating airway resistance in both healthy and asthmatic bronchioles. In vitro studies that investigate the intricate mechanisms that regulate this contractile process are predominantly conducted on tissue culture plastic, a rigid, 2D geometry, unlike the 3D microenvironment smooth muscle cells are exposed to in situ. It is increasingly apparent that cellular characteristics and responses are altered between cells cultured on 2D substrates compared with 3D topographies. Electrospinning is an attractive method to produce 3D topographies for cell culturing as the fibers produced have dimensions within the nanometer range, similar to cells' natural environment. We have developed an electrospun scaffold using the nondegradable, nontoxic, polymer polyethylene terephthalate (PET) composed of uniaxially orientated nanofibers and have evaluated this topography's effect on HASM cell adhesion, alignment, and morphology. The fibers orientation provided contact guidance enabling the formation of fully aligned sheets of smooth muscle. Moreover, smooth muscle cells cultured on the scaffold present an elongated cell phenotype with altered contractile protein levels and distribution. HASM cells cultured on this scaffold responded to the bronchoconstrictor bradykinin. The platform presented provides a novel in vitro model that promotes airway smooth muscle cell development toward a more in vivo-like phenotype while providing topological cues to ensure full cell alignment. PMID:24793171

  5. Imaging molecular structure through femtosecond photoelectron diffraction on aligned and oriented gas-phase molecules.

    PubMed

    Boll, Rebecca; Rouzée, Arnaud; Adolph, Marcus; Anielski, Denis; Aquila, Andrew; Bari, Sadia; Bomme, Cédric; Bostedt, Christoph; Bozek, John D; Chapman, Henry N; Christensen, Lauge; Coffee, Ryan; Coppola, Niccola; De, Sankar; Decleva, Piero; Epp, Sascha W; Erk, Benjamin; Filsinger, Frank; Foucar, Lutz; Gorkhover, Tais; Gumprecht, Lars; Hömke, André; Holmegaard, Lotte; Johnsson, Per; Kienitz, Jens S; Kierspel, Thomas; Krasniqi, Faton; Kühnel, Kai-Uwe; Maurer, Jochen; Messerschmidt, Marc; Moshammer, Robert; Müller, Nele L M; Rudek, Benedikt; Savelyev, Evgeny; Schlichting, Ilme; Schmidt, Carlo; Scholz, Frank; Schorb, Sebastian; Schulz, Joachim; Seltmann, Jörn; Stener, Mauro; Stern, Stephan; Techert, Simone; Thøgersen, Jan; Trippel, Sebastian; Viefhaus, Jens; Vrakking, Marc; Stapelfeldt, Henrik; Küpper, Jochen; Ullrich, Joachim; Rudenko, Artem; Rolles, Daniel

    2014-01-01

    This paper gives an account of our progress towards performing femtosecond time-resolved photoelectron diffraction on gas-phase molecules in a pump-probe setup combining optical lasers and an X-ray free-electron laser. We present results of two experiments aimed at measuring photoelectron angular distributions of laser-aligned 1-ethynyl-4-fluorobenzene (C(8)H(5)F) and dissociating, laser-aligned 1,4-dibromobenzene (C(6)H(4)Br(2)) molecules and discuss them in the larger context of photoelectron diffraction on gas-phase molecules. We also show how the strong nanosecond laser pulse used for adiabatically laser-aligning the molecules influences the measured electron and ion spectra and angular distributions, and discuss how this may affect the outcome of future time-resolved photoelectron diffraction experiments.

  6. Nanoconfinement induced crystal orientation and large piezoelectric coefficient in vertically aligned P(VDF-TrFE) nanotube array.

    PubMed

    Liew, Weng Heng; Mirshekarloo, Meysam Sharifzadeh; Chen, Shuting; Yao, Kui; Tay, Francis Eng Hock

    2015-05-12

    Vertically aligned piezoelectric P(VDF-TrFE) nanotube array comprising nanotubes embedded in anodized alumina membrane matrix without entanglement has been fabricated. It is found that the crystallographic polar axes of the P(VDF-TrFE) nanotubes are oriented along the nanotubes long axes. Such a desired crystal orientation is due to the kinetic selection mechanism for lamellae growth confined in the nanopores. The preferred crystal orientation in nanotubes leads to huge piezoelectric coefficients of the P(VDF-TrFE). The piezoelectric strain and voltage coefficients of P(VDF-TrFE) nanotube array are observed to be 1.97 and 3.40 times of those for conventional spin coated film. Such a significant performance enhancement is attributed to the well-controlled polarization orientation, the elimination of the substrate constraint, and the low dielectric constant of the nanotube array. The P(VDF-TrFE) nanotube array exhibiting the unique structure and outstanding piezoelectric performance is promising for wide applications, including various electrical devices and electromechanical sensors and transducers.

  7. Nanoconfinement induced crystal orientation and large piezoelectric coefficient in vertically aligned P(VDF-TrFE) nanotube array

    PubMed Central

    Liew, Weng Heng; Mirshekarloo, Meysam Sharifzadeh; Chen, Shuting; Yao, Kui; Tay, Francis Eng Hock

    2015-01-01

    Vertically aligned piezoelectric P(VDF-TrFE) nanotube array comprising nanotubes embedded in anodized alumina membrane matrix without entanglement has been fabricated. It is found that the crystallographic polar axes of the P(VDF-TrFE) nanotubes are oriented along the nanotubes long axes. Such a desired crystal orientation is due to the kinetic selection mechanism for lamellae growth confined in the nanopores. The preferred crystal orientation in nanotubes leads to huge piezoelectric coefficients of the P(VDF-TrFE). The piezoelectric strain and voltage coefficients of P(VDF-TrFE) nanotube array are observed to be 1.97 and 3.40 times of those for conventional spin coated film. Such a significant performance enhancement is attributed to the well-controlled polarization orientation, the elimination of the substrate constraint, and the low dielectric constant of the nanotube array. The P(VDF-TrFE) nanotube array exhibiting the unique structure and outstanding piezoelectric performance is promising for wide applications, including various electrical devices and electromechanical sensors and transducers. PMID:25966301

  8. Nanoconfinement induced crystal orientation and large piezoelectric coefficient in vertically aligned P(VDF-TrFE) nanotube array.

    PubMed

    Liew, Weng Heng; Mirshekarloo, Meysam Sharifzadeh; Chen, Shuting; Yao, Kui; Tay, Francis Eng Hock

    2015-01-01

    Vertically aligned piezoelectric P(VDF-TrFE) nanotube array comprising nanotubes embedded in anodized alumina membrane matrix without entanglement has been fabricated. It is found that the crystallographic polar axes of the P(VDF-TrFE) nanotubes are oriented along the nanotubes long axes. Such a desired crystal orientation is due to the kinetic selection mechanism for lamellae growth confined in the nanopores. The preferred crystal orientation in nanotubes leads to huge piezoelectric coefficients of the P(VDF-TrFE). The piezoelectric strain and voltage coefficients of P(VDF-TrFE) nanotube array are observed to be 1.97 and 3.40 times of those for conventional spin coated film. Such a significant performance enhancement is attributed to the well-controlled polarization orientation, the elimination of the substrate constraint, and the low dielectric constant of the nanotube array. The P(VDF-TrFE) nanotube array exhibiting the unique structure and outstanding piezoelectric performance is promising for wide applications, including various electrical devices and electromechanical sensors and transducers. PMID:25966301

  9. Critical currents and magnetization in c -axis textured Bi-Pb-Sr-Ca-Cu-O superconductors

    SciTech Connect

    Jin, S.; van Dover, R.B.; Tiefel, T.H.; Graebner, J.E. ); Spencer, N.D. )

    1991-02-25

    Transport critical currents and magnetization behavior in {ital c}-axis textured Bi-Pb-Sr-Ca-Cu-O superconductor ribbons have been studied. The highly oriented layer structure was achieved by a combination processing of spray coating on silver foil, cold rolling, and partial melting. Transport {ital J}{sub {ital c}} values as high as 2.3{times}10{sup 5} A/cm{sup 2} at 4.2 K, {ital H}=8 T ({ital H}{perpendicular}{ital ab}) have been obtained. The high {ital J}{sub {ital c}} at {ital H}{ge}5 T is maintained to temperatures near 20 K but it vanishes completely at or above {similar to}30 K, thus showing the limitation in useful, high-field operating temperatures for the Bi-system superconductors. A comparison of {ital J}{sub {ital c}} (transport) and {ital J}{sub {ital c}} (magnetization) indicates that the size scale of the circulating supercurrent loop in the Bean model nearly corresponds to the whole sample dimension rather than the orders-of-magnitude-smaller grain size. This demonstrates that the {ital a}-{ital b} grain boundaries in the melt-processed ribbons are not weakly coupled. The time decay of magnetization has also been studied.

  10. Impact of molecule-dipole orientation on energy level alignment at the submolecular scale

    NASA Astrophysics Data System (ADS)

    Huang, Y. L.; Chen, W.; Bussolotti, F.; Niu, T. C.; Wee, A. T. S.; Ueno, N.; Kera, S.

    2013-02-01

    The molecular orientation-dependent electronic properties of monolayer dipolar molecule chloroaluminum phthalocyanine (ClAlPc) on Au(111) are investigated by ultraviolet photoemission spectroscopy and scanning tunneling microscopy. The relation between geometrical and electronic structures has been revealed in the binding energies of the highest occupied molecular orbital states and vacuum level (VL) shifts. Two molecular orientations, Cl-up- and Cl-down-oriented molecules, coexist in the as-grown monolayer ClAlPc films on Au(111) without the formation of staggered molecular pairs to cancel the dipoles and phase separation, as is the case on graphite. After annealing, only the Cl-up-oriented molecules remain on Au(111), as on graphite. Interestingly, an extraordinarily large VL shift of -0.89 eV is observed in the annealed monolayer ClAlPc film on Au(111), which is opposite to that of +0.46 eV on graphite even though the molecular dipoles are oriented similarly.

  11. Fabrication of alumina porous scaffolds with aligned oriented pores for bone tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Sarhadi, Fatemeh; Shafiee Afarani, Mahdi; Mohebbi-Kalhori, Davod; Shayesteh, Masoud

    2016-04-01

    In the present study, porous alumina scaffolds with specific orientation and anisotropic properties are fabricated for application in bone tissue repair. The scaffolds with double shape pores, tubular oriented and isotropic rounded pores, were prepared using alumina and silica as starting materials by the slip casting route. Milled polyurethane foam and silk fibers were applied as replica materials as well. The effect of fiber types and diameter and number of fibers on the microstructure and pore size was studied. Moreover, different characteristics such as porosity, density, orientation, flexural strength and compressive strength of the samples were investigated. Results showed that various fibers with different diameters and numbers led to forming the pores with different pore sizes, microstructure and consequently changes in the physical and mechanical properties. In addition, the simultaneous presence of fibers and particles led to more porous scaffolds. The oriented tiny micro-tube and rounded pores were observed in all porous ceramic scaffolds. Mechanical testing showed an anisotropy in the mechanical behaviors such that higher strengths were observed in the oriented pore direction than that of transverse. With increasing the number and diameter of silk fibers, the scaffolds with a high porosity up to 68 vol% and proper flexural strength were obtained.

  12. Epitaxial growth of biaxially oriented YBCO films on silver

    NASA Astrophysics Data System (ADS)

    Liu, Danmin; Zhou, Meiling; Wang, Xue; Suo, Hongli; Zuo, Tieyong; Schindl, Michael; Flükiger, René

    2001-09-01

    YBCO films were deposited on (100), (110) and (111) oriented silver single crystals and { 100} <100>, { 110} <211> and { 012} <100> biaxially textured Ag substrates by pulsed laser deposition. It is shown that the (100) and (110) orientated single crystals and the { 110} biaxially textured Ag tape are all suitable for the deposition of YBCO thin films with c-axis in-plane alignment. The Jc of YBCO film deposited on { 110} <211> biaxially textured Ag foil is 7×105A cm-2 at 77 K, 0 T. A scheme for the regular growth of YBCO on silver was put forward.

  13. Effect of magnetic field strength on the alignment of α''-Fe16N2 nanoparticle films

    NASA Astrophysics Data System (ADS)

    Kartikowati, Christina W.; Suhendi, Asep; Zulhijah, Rizka; Ogi, Takashi; Iwaki, Toru; Okuyama, Kikuo

    2016-01-01

    Aligning the magnetic orientation is one strategy to improve the magnetic performance of magnetic materials. In this study, well-dispersed single-domain core-shell α''-Fe16N2/Al2O3 nanoparticles (NPs) were aligned by vertically applying magnetic fields with various strengths to a Si wafer substrate followed by fixation with resin. X-ray diffraction indicated that the alignment of the easy c-axis of the α''-Fe16N2 crystal and the magnetic orientation of the NPs depended upon the applied magnetic field. Magnetic analysis demonstrated that increasing the magnetic field strength resulted in hysteresis loops approaching a rectangular form, implying a higher magnetic coercivity, remanence, and maximum energy product. The same tendency was also observed when a horizontal magnetic field was applied. The fixation of the easy c-axis alignment of each nanoparticle caused by Brownian rotation under the magnetic field, instead of Néel rotation, was the reason for the enhancement in the magnetic performance. These results on the alignment of the magnetic orientation of α''-Fe16N2 NPs suggest the practical application of high-performance permanent bulk magnets from well-dispersed single-domain α''-Fe16N2/Al2O3 NPs.

  14. Effect of magnetic field strength on the alignment of α''-Fe16N2 nanoparticle films.

    PubMed

    Kartikowati, Christina W; Suhendi, Asep; Zulhijah, Rizka; Ogi, Takashi; Iwaki, Toru; Okuyama, Kikuo

    2016-02-01

    Aligning the magnetic orientation is one strategy to improve the magnetic performance of magnetic materials. In this study, well-dispersed single-domain core-shell α''-Fe16N2/Al2O3 nanoparticles (NPs) were aligned by vertically applying magnetic fields with various strengths to a Si wafer substrate followed by fixation with resin. X-ray diffraction indicated that the alignment of the easy c-axis of the α''-Fe16N2 crystal and the magnetic orientation of the NPs depended upon the applied magnetic field. Magnetic analysis demonstrated that increasing the magnetic field strength resulted in hysteresis loops approaching a rectangular form, implying a higher magnetic coercivity, remanence, and maximum energy product. The same tendency was also observed when a horizontal magnetic field was applied. The fixation of the easy c-axis alignment of each nanoparticle caused by Brownian rotation under the magnetic field, instead of Néel rotation, was the reason for the enhancement in the magnetic performance. These results on the alignment of the magnetic orientation of α''-Fe16N2 NPs suggest the practical application of high-performance permanent bulk magnets from well-dispersed single-domain α''-Fe16N2/Al2O3 NPs.

  15. Contour integration and aging: the effects of element spacing, orientation alignment and stimulus duration.

    PubMed

    Roudaia, Eugenie; Bennett, Patrick J; Sekuler, Allison B

    2013-01-01

    The ability to extract contours in cluttered visual scenes, which is a crucial step in visual processing, declines with healthy aging, but the reasons for this decline are not well understood. In three experiments, we examined how the effect of aging on contour discrimination varies as a function of contour and distracter inter-element spacing, collinearity, and stimulus duration. Spiral-shaped contours composed of Gabors were embedded within a field of distracter Gabors of uniform density. In a four alternative forced-choice task, younger and older subjects were required to report the global orientation of the contour. In Experiment 1, the absolute contour element spacing varied from two to eight times the Gabor wavelength and contour element collinearity was disrupted with five levels of orientation jitter. Contour discrimination accuracy was lower in older subjects, but the effect of aging did not vary with contour spacing or orientation jitter. Experiment 2 found that decreasing stimulus durations from 0.8 to 0.04 s had a greater effect on older subjects' performance, but only for less salient contours. Experiment 3 examined the effect of the background on contour discrimination by varying the spacing and orientation of the distracter elements for contours with small and large absolute spacing. As in Experiment, the effect of aging did not vary with absolute contour spacing. Decreasing the distracter spacing, however, had a greater detrimental effect on accuracy in older subjects compared to younger subjects. Finally, both groups showed equally high accuracy when all distracters were iso-oriented. In sum, these findings suggest that aging does not affect the sensitivity of contour integration to proximity or collinearity. However, contour integration in older adults is slower and is especially vulnerable when distracters are denser than contour elements.

  16. Orientational alignment in solids from bidimensional isotropic-anisotropic nuclear magnetic resonance spectroscopy: applications to the analysis of aramide fibers.

    PubMed

    Sachleben, J R; Frydman, L

    1997-02-01

    The use of two-dimensional isotropic-anisotropic correlation spectroscopy for the analysis of orientational alignment in solids is presented. The theoretical background and advantages of this natural-abundance 13C NMR method of measurement are discussed, and demonstrated with a series of powder and single-crystal variable-angle correlation spectroscopy (VACSY) experiments on model systems. The technique is subsequently employed to analyze the orientational distributions of three polymer fibers: Kevlar 29, Kevlar 49 and Kevlar 149. Using complementary two-dimensional NMR data recorded on synthetic samples of poly(p-phenyleneterephthalamide), the precursor of Kevlar, it was found that these commercial fibers possess molecules distributed over a very narrow orientational range with respect to the macroscopic director. The widths measured for these director distribution arrangements were (12 +/- 1.5) degrees for Kevlar 29, (15 +/- 1.5) degrees for Kevlar 49, and (8 +/- 1.5) degrees for Kevlar 149. These figures compare well with previous results obtained for non-commercial fiber samples derived from the same polymer.

  17. Note: Non-invasive optical method for rapid determination of alignment degree of oriented nanofibrous layers

    NASA Astrophysics Data System (ADS)

    Pokorny, M.; Klemes, J.; Rebicek, J.; Kotzianova, A.; Velebny, V.

    2015-10-01

    This paper presents a rapid non-destructive method that provides information on the anisotropic internal structure of nanofibrous layers. A laser beam of a wavelength of 632.8 nm is directed at and passes through a nanofibrous layer prepared by electrostatic spinning. Information about the structural arrangement of nanofibers in the layer is directly visible in the form of a diffraction image formed on a projection screen or obtained from measured intensities of the laser beam passing through the sample which are determined by the dependency of the angle of the main direction of polarization of the laser beam on the axis of alignment of nanofibers in the sample. Both optical methods were verified on Polyvinyl alcohol (PVA) nanofibrous layers (fiber diameter of 470 nm) with random, single-axis aligned and crossed structures. The obtained results match the results of commonly used methods which apply the analysis of electron microscope images. The presented simple method not only allows samples to be analysed much more rapidly and without damaging them but it also makes possible the analysis of much larger areas, up to several square millimetres, at the same time.

  18. Note: Non-invasive optical method for rapid determination of alignment degree of oriented nanofibrous layers

    SciTech Connect

    Pokorny, M.; Rebicek, J.; Klemes, J.; Kotzianova, A.; Velebny, V.

    2015-10-15

    This paper presents a rapid non-destructive method that provides information on the anisotropic internal structure of nanofibrous layers. A laser beam of a wavelength of 632.8 nm is directed at and passes through a nanofibrous layer prepared by electrostatic spinning. Information about the structural arrangement of nanofibers in the layer is directly visible in the form of a diffraction image formed on a projection screen or obtained from measured intensities of the laser beam passing through the sample which are determined by the dependency of the angle of the main direction of polarization of the laser beam on the axis of alignment of nanofibers in the sample. Both optical methods were verified on Polyvinyl alcohol (PVA) nanofibrous layers (fiber diameter of 470 nm) with random, single-axis aligned and crossed structures. The obtained results match the results of commonly used methods which apply the analysis of electron microscope images. The presented simple method not only allows samples to be analysed much more rapidly and without damaging them but it also makes possible the analysis of much larger areas, up to several square millimetres, at the same time.

  19. Wave Propagation Direction and c-Axis Tilt Angle Influence on the Performance of ScAlN/Sapphire-Based SAW Devices.

    PubMed

    Kochhar, Abhay; Yamamoto, Yasuo; Teshigahara, Akihiko; Hashimoto, Ken-Ya; Tanaka, Shuji; Esashi, Masayoshi

    2016-07-01

    Some previously reported surface acoustic wave (SAW) devices using bulk piezoelectric substrates showed higher acoustic power radiated in either forward or backward wave propagation direction depending on their crystal orientations and are called natural single-phase unidirectional transducers (NSPUDT). While these reports were based on bulk piezoelectric substrates, we report directionality in the c-axis tilted 44% scandium doped aluminum nitride thin piezoelectric film-based SAW devices on sapphire. It is worth noting that our observance of directionality is specifically in Sezawa mode. We produced a c-axis tilt up to 5.5° over the single wafer and examined the directionality by comparing the forward and backward insertion loss utilizing split finger electrodes as a receiver. The wave propagation direction and c-axis tilt angle influence on the performance of SAW devices is evaluated. Furthermore, return loss and insertion loss data are presented for various SAW propagation directions and c-axis tilt angles. Finally, the comparison for both acoustic modes, i.e., Rayleigh and Sezawa, is reported. PMID:26978772

  20. Quartz c-axis fabric development associated with shear deformation along an extensional detachment shear zone: Chapedony Metamorphic Core Complex, Central-East Iranian Microcontinent

    NASA Astrophysics Data System (ADS)

    Faghih, Ali; Soleimani, Masoumeh

    2015-01-01

    Lattice preferred orientations (LPOs) of quartz were used to establish differences in deformation geometry, finite strain and temperature across an extensional detachment shear zone within the Chapedony Metamorphic Core Complex in the Central-East Iranian Microcontinent along the northern flank of Gondwana. Quartz c-axis data show a continuous evolution across the core complex from asymmetric Type I crossed girdles at the southwest margin, to broken, asymmetric Type I crossed girdle and single girdle with a large concentration of axes plotted in the center of the stereoplot at the central parts of the core complex and small circle girdle pattern at the northeast margin. These variations in quartz c-axis patterns imply change in strain geometry during deformation from plane strain to general flattening and pure flattening. Integrating analyses of quartz c-axis opening angles, quartz c-axis patterns and recrystalization regimes of quartz and feldspar suggests deformation temperatures range between less than 400 °C and 650 °C, which yield greenschist to amphibolite facies conditions. Mean kinematic vorticity number (Wm) measured in the mylonite samples ranges between 0.67 and 0.71, which indicates that exhumation of the metamorphic rocks of the CMCC was facilitated by a significant component of pure shear strain within a general shear regime.

  1. CW dipolar broadening EPR spectroscopy and mechanically aligned bilayers used to measure distance and relative orientation between two TOAC spin labels on an antimicrobial peptide

    NASA Astrophysics Data System (ADS)

    Sahu, Indra D.; Hustedt, Eric J.; Ghimire, Harishchandra; Inbaraj, Johnson J.; McCarrick, Robert M.; Lorigan, Gary A.

    2014-12-01

    An EPR membrane alignment technique was applied to measure distance and relative orientations between two spin labels on a protein oriented along the surface of the membrane. Previously we demonstrated an EPR membrane alignment technique for measuring distances and relative orientations between two spin labels using a dual TOAC-labeled integral transmembrane peptide (M2δ segment of Acetylcholine receptor) as a test system. In this study we further utilized this technique and successfully measured the distance and relative orientations between two spin labels on a membrane peripheral peptide (antimicrobial peptide magainin-2). The TOAC-labeled magainin-2 peptides were mechanically aligned using DMPC lipids on a planar quartz support, and CW-EPR spectra were recorded at specific orientations. Global analysis in combination with rigorous spectral simulation was used to simultaneously analyze data from two different sample orientations for both single- and double-labeled peptides. We measured an internitroxide distance of 15.3 Å from a dual TOAC-labeled magainin-2 peptide at positions 8 and 14 that closely matches with the 13.3 Å distance obtained from a model of the labeled magainin peptide. In addition, the angles determining the relative orientations of the two nitroxides have been determined, and the results compare favorably with molecular modeling. This study demonstrates the utility of the technique for proteins oriented along the surface of the membrane in addition to the previous results for proteins situated within the membrane bilayer.

  2. Topology of surfaces for molecular Stark energy, alignment, and orientation generated by combined permanent and induced electric dipole interactions

    SciTech Connect

    Schmidt, Burkhard; Friedrich, Bretislav

    2014-02-14

    We show that combined permanent and induced electric dipole interactions of linear polar and polarizable molecules with collinear electric fields lead to a sui generis topology of the corresponding Stark energy surfaces and of other observables – such as alignment and orientation cosines – in the plane spanned by the permanent and induced dipole interaction parameters. We find that the loci of the intersections of the surfaces can be traced analytically and that the eigenstates as well as the number of their intersections can be characterized by a single integer index. The value of the index, distinctive for a particular ratio of the interaction parameters, brings out a close kinship with the eigenproperties obtained previously for a class of Stark states via the apparatus of supersymmetric quantum mechanics.

  3. Topology of surfaces for molecular Stark energy, alignment, and orientation generated by combined permanent and induced electric dipole interactions.

    PubMed

    Schmidt, Burkhard; Friedrich, Bretislav

    2014-02-14

    We show that combined permanent and induced electric dipole interactions of linear polar and polarizable molecules with collinear electric fields lead to a sui generis topology of the corresponding Stark energy surfaces and of other observables - such as alignment and orientation cosines - in the plane spanned by the permanent and induced dipole interaction parameters. We find that the loci of the intersections of the surfaces can be traced analytically and that the eigenstates as well as the number of their intersections can be characterized by a single integer index. The value of the index, distinctive for a particular ratio of the interaction parameters, brings out a close kinship with the eigenproperties obtained previously for a class of Stark states via the apparatus of supersymmetric quantum mechanics.

  4. Large-scale horizontally aligned ZnO microrod arrays with controlled orientation, periodic distribution as building blocks for chip-in piezo-phototronic LEDs.

    PubMed

    Guo, Zhen; Li, Haiwen; Zhou, Lianqun; Zhao, Dongxu; Wu, Yihui; Zhang, Zhiqiang; Zhang, Wei; Li, Chuanyu; Yao, Jia

    2015-01-27

    A novel method of fabricating large-scale horizontally aligned ZnO microrod arrays with controlled orientation and periodic distribution via combing technology is introduced. Horizontally aligned ZnO microrod arrays with uniform orientation and periodic distribution can be realized based on the conventional bottom-up method prepared vertically aligned ZnO microrod matrix via the combing method. When the combing parameters are changed, the orientation of horizontally aligned ZnO microrod arrays can be adjusted (θ = 90° or 45°) in a plane and a misalignment angle of the microrods (0.3° to 2.3°) with low-growth density can be obtained. To explore the potential applications based on the vertically and horizontally aligned ZnO microrods on p-GaN layer, piezo-phototronic devices such as heterojunction LEDs are built. Electroluminescence (EL) emission patterns can be adjusted for the vertically and horizontally aligned ZnO microrods/p-GaN heterojunction LEDs by applying forward bias. Moreover, the emission color from UV-blue to yellow-green can be tuned by investigating the piezoelectric properties of the materials. The EL emission mechanisms of the LEDs are discussed in terms of band diagrams of the heterojunctions and carrier recombination processes.

  5. Charge dynamics along the less conducting c-axis of the layered transition metal dichalcogenides

    NASA Astrophysics Data System (ADS)

    Ruzicka, B.; Degiorgi, L.; Berger, H.; Gaal, R.; Forro, L.

    2001-03-01

    We present optical results on 2H-TaSe2 along the less conducting c-axis. This dichalcogenide compound belongs to a large class of conductors called "bad metals" (with mean free path smaller than the lattice constant along the c-axis), which also includes the superconducting cuprates. The optical response shows the progressive development of a pseudogap-like feature with decreasing temperature. The spectral weight lost by the opening of such a pseudogap goes into the narrow Drude component, developing at low frequency and temperature. There is no violation of the sum rule in 2H-TaSe2 contrary to the cuprates. Furthermore, we will discuss the c-axis response with respect to our recent results within the two-dimensional ab-plane. The data on 2H-TaSe2 will be also compared to our results on the superconducting 2H-NbSe2 dichalcogenide material.

  6. The non-epitaxial growth of c-axis YBa 2Cu 3O x films on high-index planes of silver

    NASA Astrophysics Data System (ADS)

    Huang, D. X.; Yamada, Y.; Hirabayashi, I.

    2000-11-01

    YBa 2Cu 3O x (YBCO) thin films were deposited by the pulsed-laser ablation on polycrystalline Ag substrates. The c-axis-oriented YBCO films on various high-index silver crystal planes have been observed using cross-sectional transmission electron microscopy (TEM). The obtained results show that, differing from the epitaxial growth of the YBCO films on low-index planes, the YBCO films grown on high-index planes have not a good epitaxial relationship. The c-axes of the YBCO grains keep to vertical to the substrate surface plane but the a- and b- axes of the grains are randomly oriented.

  7. Transport Anisotropy in ErNi2B2C Along c-AXIS

    NASA Astrophysics Data System (ADS)

    Lee, W. C.

    The resistivities along c-axis ρc(H, T) of ErNi2 B2C have been measured with H⊥ and H‖ c-axis for 2 < T < 300 K and the superconducting upper critical field Hc2(T) curves of ErNi2B2C were constructed for each magnetic fields. Our Hc2(T) curves have been compared and discussed with those from ρab(H, T) measurements which explain the anisotropy and its temperature dependence of Hc2(T) are thought to arise from magnetic pair breaking and the anisotropic field dependence of Néel temperature TN originated from Er+3 sublattice.

  8. Magnetic alignment experiment of fine graphite-crystals dispersed in He gas oriented to study alignment of crystalline-axes of nano-sized non-magnetic particles.

    PubMed

    Uyeda, C; Skakibara, M; Tanaka, K; Takashima, R

    2005-01-01

    The ensemble of nano-sized crystals is expected to attain additional physical properties when preferential alignments of certain crystal-axes are achieved by a magnetic field. The reduction of temperature T may realize alignment even if the mole number of the particle N and the diamagnetic anisotropy per mole (Deltachi)(DIA) are considerably small for the nano-sized diamagnetic oxides, since alignment proceeds by the balance between the energy of rotational Brownian motion and field-induced anisotropy energy. Alignment of various basic inorganic oxides such as gypsum, quartz, forsterite, KDP or calcite, having a size of 20 nm diameter, is expected to occur by a field intensity of approximately 50 T at T = 10 K; this intensity is presently available at a high magnetic-field laboratory. It is expected that the magnetic alignment of nano-sized particles can be observed by dispersing the particles in He gas, as achieved recently for micron-sized graphite crystals; a cryogenic liquid cannot be used as a dispersing medium. Measured (Deltachi)(DIA) values accumulated for basic inorganic-oxides are explained quantitatively by assuming that individual bonding-orbital composing the material possesses a constant amount of diamagnetic anisotropy; hence the majority of diamagnetic nano-sized insulators are expected to show magnetic alignment at finite field intensity.

  9. Effect of strain along C-axis NbS{sub 2}

    SciTech Connect

    Singh, Tapender Kumar, Jagdish Sastri, O. S. K. S.

    2015-05-15

    We have studied electronic properties of double layered hexagonal structure of the Niobium Di-Sulphide (2H-NbS{sub 2}) superconductor for various strains introduced along the c-axis using ab-initio calculations. The DFT calculations based on Full Potential Linearized Augmented Plane Wave (FPLAPW) method are performed using the ELK code. The total energy curve (E vs a), Density of States (DOS) and the Band structure calculations obtained in this work are matching with the earlier reports. The Pressure-Volume (P-V) diagram for 2H-NbS{sub 2} was obtained using the Equation of State(EOS) calculations, which provides the relationship between the pressure and strain applied along the c-axis. The band structures for various strains ranging from 0 percent to 10 percent along c-axis in steps of 2 percent are obtained. We note that there are increasing number of bands crossing over the Fermi energy level with increase in strain. Thus, we conclude that with increasing strain along c-axis, number of conduction bands crossing the E{sub F} increases, which gives rise to more conduction states and hence higher conductivity.

  10. Effect of strain along C-axis NbS2

    NASA Astrophysics Data System (ADS)

    Singh, Tapender; Kumar, Jagdish; Sastri, O. S. K. S.

    2015-05-01

    We have studied electronic properties of double layered hexagonal structure of the Niobium Di-Sulphide (2H-NbS2) superconductor for various strains introduced along the c-axis using ab-initio calculations. The DFT calculations based on Full Potential Linearized Augmented Plane Wave (FPLAPW) method are performed using the ELK code. The total energy curve (E vs a), Density of States (DOS) and the Band structure calculations obtained in this work are matching with the earlier reports. The Pressure-Volume (P-V) diagram for 2H-NbS2 was obtained using the Equation of State(EOS) calculations, which provides the relationship between the pressure and strain applied along the c-axis. The band structures for various strains ranging from 0 percent to 10 percent along c-axis in steps of 2 percent are obtained. We note that there are increasing number of bands crossing over the Fermi energy level with increase in strain. Thus, we conclude that with increasing strain along c-axis, number of conduction bands crossing the EF increases, which gives rise to more conduction states and hence higher conductivity.

  11. In-plane and c-axis optical spectroscopy study on 122 Fe-pnictides

    NASA Astrophysics Data System (ADS)

    Wang, Nan Lin

    2011-03-01

    I present the in-plane and the c-axis optical spectroscopy investigations on 122 Fe-pnictides. For the parent compound BaFe 2 As 2 , the in-plane measurement revealed two different energy gaps in the SDW state, whereas for the c-axis polarized measurement only the energy gap at smaller energy scale could be clearly observed. We suggest different driving mechanisms for the formation of the two energy gaps. The large energy gap is caused by the nesting between disconnected 2D cylinder-like electron and hole Fermi surfaces. It is the main driving force for the SDW instability. The small energy gap is the one formed on the 3D Fermi surface due to the presence of reduced magnetic Brillouin zone which crosses the 3D Fermi surface. It is the consequence of the establishment of the magnetic order. For the doped superconducting 122 samples, the in-plane optical measurement revealed a formation of full superconducting energy gap, whereas the c-axis optical measurement indicated a large residual quasiparticle population down to very low temperature. Those quasiparticles contribute specifically to the c-axis transport. We suggest that there exist horizontal nodes in the superconducting gap in regions of the 3D Fermi surface that contribute dominantly to the c-axis optical conductivity. Work done with Z. G. Chen, W. Z. Hu, B. Cheng, G. Li, J. Dong, T. Dong, R. H. Yuan, P. Zheng, G. F. Chen, J. L. Luo, Z. Fang, X. Dai, C. L. Zhang and P. Dai.

  12. THE BANANA PROJECT. IV. TWO ALIGNED STELLAR ROTATION AXES IN THE YOUNG ECCENTRIC BINARY SYSTEM EP CRUCIS: PRIMORDIAL ORIENTATION AND TIDAL ALIGNMENT

    SciTech Connect

    Albrecht, Simon; Winn, Joshua N.; Setiawan, Johny; Torres, Guillermo; Fabrycky, Daniel C.

    2013-04-10

    With observations of the EP Cru system, we continue our series of measurements of spin-orbit angles in eclipsing binary star systems, the BANANA project (Binaries Are Not Always Neatly Aligned). We find a close alignment between the sky projections of the rotational and orbital angular momentum vectors for both stars ({beta}{sub p} = -1. Degree-Sign 8 {+-} 1. Degree-Sign 6 and |{beta}{sub s}| < 17 Degree-Sign ). We also derive precise absolute dimensions and stellar ages for this system. The EP Cru and DI Her systems provide an interesting comparison: they have similar stellar types and orbital properties, but DI Her is younger and has major spin-orbit misalignments, raising the question of whether EP Cru also had a large misalignment at an earlier phase of evolution. We show that tidal dissipation is an unlikely explanation for the good alignment observed today, because realignment happens on the same timescale as spin-orbit synchronization, and the stars in EP Cru are far from synchronization (they are spinning nine times too quickly). Therefore it seems that some binaries form with aligned axes, while other superficially similar binaries are formed with misaligned axes.

  13. Contrôle de l'orientation et de l'alignement moléculaire par un train d'impulsions soudaines

    NASA Astrophysics Data System (ADS)

    Sugny, D.

    2006-10-01

    Les récents progrès technologiques dans le domaine des Lasers permettent d'envisager le contrôle de nombreux processus quantiques jouant un rôle dans une variété de problèmes s'étendant de la réactivité chimique à l'information quantique. Dans ce contexte, nous nous sommes intéressés au contrôle de l'orientation ou de l'alignement moléculaire en utilisant un train d'impulsions soudaines. Nous avons défini des états cibles qui maximisent à la fois l'orientation ou l'alignement et sa durée dans le temps et montré comment atteindre ces états à l'aide de stratégie systématique ou optimisée

  14. X-Ray Studies of Layer Rigidity and C-Axis Expansion in Intercalated Layered Solids.

    NASA Astrophysics Data System (ADS)

    Lee, Soonil

    From X-ray diffraction and Raman active torsional model frequency studies the new synthetic vermiculite intercalation compounds, ((CH_3)_4N ^+) _{rm x} ((CH_3)_3NH ^+) _{rm 1-x} -Vm, are determined to have a solid solution type mixed gallery cation distribution. The x dependence of the normalized basal spacing, d_{rm n}(x), of ternary pillared vermiculite ((CH_3)_4 N^+) _{ rm x} ((CH_3)_3 NH^+) _{ rm 1-x}-Vm has been measured and compared with that of Cs_{rm x}Rb _{rm 1-x}-Vm. Both systems exhibit a nonlinear d_{rm n}(X) with approximate thresholds of x ~ 0.2 and 0.5, respectively. A model which relates d_{rm n}(x) to layer rigidity and the binding energies of gallery and defect sites yields excellent fits to the basal spacing data and to monolayer simulations if collective effects are included. We also have constructed a plot of the normalized basal spacing versus normalized torsional model frequency for two vermiculite intercalation compounds, Cs _{rm x}Rb_ {rm 1-x}-Vm and ((CH_3) _4N^+) _ {rm x} ((CH_3)_3 NH^+) _{ rm 1-x}-Vm. This plot shows a striking "scaling-like"behavior for the two different mixed-ion systems. An attempt to understand this behavior based on the virtual crystal approximation has been made. This mode calculation reveals a very close relationship between the basal spacing and the gallery ion-oxygen interaction. A layer rigidity model which includes the effects of elastic deformation of the host layers is applied to a variety of layered intercalation compounds. This model can account for the composition dependence of the c-axis expansion of the three classes of layered solids. Rigidity parameters deduced from this model for each of the three classes of layered solid are reflective of structurally derived rigidity as are the healing lengths computed on the basis of discrete and continuum analyses. Using the continuum elastic theory the attractive intralayer interaction in intercalation compounds is calculated to show the contribution of each

  15. C-axis critical current density of second-generation YBCO tapes.

    SciTech Connect

    Jia, Y.; Hua, J.; Crabtree, G. W.; Kwok, W. K.; Welp, U.; Malozemoff, A. P.; Rupich, M.; Fleshler, S.; Materials Science Division; American Superconductor Corp.

    2010-10-01

    We report on measurements of the temperature and field dependence of the c-axis critical current density (J{sub c}{sup c}) obtained on mesa structures that were patterned into the YBCO layer of second-generation HTS tapes. We find the J{sub c}{sup c}-values of {approx}4 kA cm{sup -2} at 77 K and self-field, corresponding to an unexpectedly high anisotropy in the critical current density J{sub c}{sup ab}/J{sub c}{sup c} of 500-600. C-axis current flow is expected to arise in applications such as the helically wound wires in HTS cables. A simple estimate is given of the fraction of tape width for such a c-axis flow; while in our samples this fraction is approximately 5% for a typical geometry, the fraction will grow linearly with increasing current density anisotropy and could affect the current-carrying ability of the tape.

  16. Quartz c-axis evidence for deformation characteristics in the Sanandaj-Sirjan metamorphic belt, Iran

    NASA Astrophysics Data System (ADS)

    Samani, Babak

    2013-05-01

    Quartz c-axis fabric, finite strain, and kinematic vorticity analyses were carried out in well-exposed quartz mylonites to investigate the heterogeneous nature of ductile deformation within the Eghlid deformed area in the High Pressure-Low Temperature (HP-LT) Sanandaj-Sirjan metamorphic belt (Zagros Mountains, Iran). This belt belongs to a sequence of tectonometamorphic complexes with low- to high-grade metamorphic rocks affected by a polyphase deformation history. Asymmetric quartz c-axis fabrics (type I) confirm a localized top-to-the-southeast sense of shear. Quantitative finite strain analysis in the XZ, XY and YZ principal planes of the finite strain ellipsoid demonstrate that the strain ratio increases towards the thrust planes of the Zagros Thrust System. Kinematic vorticity analysis of deformed quartz grains showed sequential variation in the kinematic vorticity number from ˜0.5 to ˜0.8 between the thrust sheets. Such vorticity numbers show that both simple and pure shear components contribute to the deformation. Our results show that simple shear dominated deformation near the thrust faults, and pure shear dominated deformation far from them. Quartz c-axis opening angles suggest deformation temperatures range between 450° ± 50 °C and 600° ± 50 °C, which yield greenschist to amphibolite facies conditions during ductile deformation.

  17. Substrate Heating Effect on c-Axis Texture and Piezoelectric Properties of AlN Thin Films Deposited by Unbalanced Magnetron Sputtering

    NASA Astrophysics Data System (ADS)

    Hasheminiasari, Masood; Lin, Jianliang

    2016-06-01

    Aluminum nitride (AlN) thin films with highly preferred (002) orientations have been reactively deposited by a pulsed-closed field unbalanced magnetron sputtering system using TiN/Ti as the seed/adhesion layer with various substrate temperatures. The texture, orientation and piezoelectric properties of AlN films were characterized by means of x-ray diffraction, rocking curves and laser interferometry. A Michelson laser interferometer was designed and built to obtain the converse piezoelectric response of the deposited AlN thin films. It was found that a slight substrate temperature increase would significantly affect the (002) orientation and the piezoelectric coefficient of AlN thin films compared to the coating obtained with no intentional substrate heating, while higher temperature applications on substrate deteriorated the c-axis texture of the coatings without significant improvement in the piezoelectric response of AlN films.

  18. Tracing kinematic (mis)alignments in CALIFA merging galaxies. Stellar and ionized gas kinematic orientations at every merger stage

    NASA Astrophysics Data System (ADS)

    Barrera-Ballesteros, J. K.; García-Lorenzo, B.; Falcón-Barroso, J.; van de Ven, G.; Lyubenova, M.; Wild, V.; Méndez-Abreu, J.; Sánchez, S. F.; Marquez, I.; Masegosa, J.; Monreal-Ibero, A.; Ziegler, B.; del Olmo, A.; Verdes-Montenegro, L.; García-Benito, R.; Husemann, B.; Mast, D.; Kehrig, C.; Iglesias-Paramo, J.; Marino, R. A.; Aguerri, J. A. L.; Walcher, C. J.; Vílchez, J. M.; Bomans, D. J.; Cortijo-Ferrero, C.; González Delgado, R. M.; Bland-Hawthorn, J.; McIntosh, D. H.; Bekeraitė, S.

    2015-10-01

    We present spatially resolved stellar and/or ionized gas kinematic properties for a sample of 103 interacting galaxies, tracing all merger stages: close companions, pairs with morphological signatures of interaction, and coalesced merger remnants. In order to distinguish kinematic properties caused by a merger event from those driven by internal processes, we compare our galaxies with a control sample of 80 non-interacting galaxies. We measure for both the stellar and the ionized gas components the major (projected) kinematic position angles (PAkin, approaching and receding) directly from the velocity distributions with no assumptions on the internal motions. This method also allow us to derive the deviations of the kinematic PAs from a straight line (δPAkin). We find that around half of the interacting objects show morpho-kinematic PA misalignments that cannot be found in the control sample. In particular, we observe those misalignments in galaxies with morphological signatures of interaction. On the other hand, thelevel of alignment between the approaching and receding sides for both samples is similar, with most of the galaxies displaying small misalignments. Radial deviations of the kinematic PA orientation from a straight line in the stellar component measured by δPAkin are large for both samples. However, for a large fraction of interacting galaxies the ionized gas δPAkin is larger than the typical values derived from isolated galaxies (48%), indicating that this parameter is a good indicator to trace the impact of interaction and mergers in the internal motions of galaxies. By comparing the stellar and ionized gas kinematic PA, we find that 42% (28/66) of the interacting galaxies have misalignments larger than 16°, compared to 10% from the control sample. Our results show the impact of interactions in the motion of stellar and ionized gas as well as the wide the variety of their spatially resolved kinematic distributions. This study also provides a local

  19. Fabrication of Aligned Conducting PPy-PLLA Fiber Films and Their Electrically Controlled Guidance and Orientation for Neurites.

    PubMed

    Zou, Yuanwen; Qin, Jiabang; Huang, Zhongbing; Yin, Guangfu; Pu, Ximing; He, Da

    2016-05-25

    Electrically conductive biomaterial scaffolds have great potential in neural tissue regeneration. In this work, an aligned conductive fibrous scaffold was prepared by electrospinning PLLA on rotating collector and chemical oxidation polymerization of pyrrole (PPy) codoped with poly(glutamic acid)/dodecyl benzenesulfonic acid sodium. The characterization results of composition, structure and mechanics of fiber films show that the existence of weak polar van der Waals' force between PPy coating and PLLA fibers. The resistivity of aligned rough PPy-PLLA fiber film (about 800 nm of fiber diameter) at the perpendicular and parallel directions is 0.971 and 0.874 Ω m, respectively. Aligned rough PPy-PLLA fiber film could guide the extension of 68% PC12 neurites along the direction of fiber axis. Under electrostimulation (ES) of 100, 200, and 400 mV/cm, median neurite lengths of differentiated PC12 on aligned fiber-films are 128, 149, and 141 μm, respectively. Furthermore, under ES of 100, 200, and 400 mV/cm, the alignment rate of neurite along the electropotential direction (angle between neurite and electropotential direction ≤10°) on random fibers film are 17, 23, and 28%, respectively, and the alignment rate of neurites along the fiber axis (angle between neurite and fiber axis ≤10°) on aligned fibers film reach to 76, 83, and 79%, respectively, indicating that the combination of ES and rough conducting aligned structure could adjust the alignment of cellular neurites along the direction of the fiber axis or electropotential. PMID:27172537

  20. Orientation dependant charge transfer at fullerene/Zn-phthalocyanine (C60/ZnPc) interface: Implications for energy level alignment and photovoltaic properties

    NASA Astrophysics Data System (ADS)

    Javaid, Saqib; Javed Akhtar, M.

    2016-08-01

    Recently, experimental results have shown that photovoltaic properties of Fullerene (C60)/Phthalocyanine based devices improve considerably as molecular orientation is changed from edge-on to face-on. In this work, we have studied the impact of molecular orientation on C60/ZnPc interfacial properties, particularly focusing on experimentally observed face-on and edge-on configuration, using density functional theory based simulations. The results show that the interfacial electronic properties are strongly anisotropic: direction of charge transfer and interface dipole fluctuates as molecular orientation is switched. As a result of orientation dependant interface dipole, difference between acceptor LUMO and donor HOMO increases as the orientation is changed from edge-on to face-on, suggesting a consequent increase in open circuit voltage (VOC). Moreover, adsorption and electronic properties indicate that the interfacial interactions are much stronger in the face-on configuration which should further facilitate the charge-separation process. These findings elucidate the energy level alignment at C60/ZnPc interface and help to identify interface dipole as the origin of the orientation dependence of VOC.

  1. Biological apatite (BAp) crystallographic orientation and texture as a new index for assessing the microstructure and function of bone regenerated by tissue engineering.

    PubMed

    Nakano, Takayoshi; Kaibara, Kazuhiro; Ishimoto, Takuya; Tabata, Yasuhiko; Umakoshi, Yukichi

    2012-10-01

    Recently, there have been remarkable advances in medical techniques for regenerating bone defects. To determine the degree of bone regeneration, it is essential to develop a new method that can analyze microstructure and related mechanical function. Here, quantitative analysis of the orientation distribution of biological apatite (BAp) crystallites by a microbeam X-ray diffractometer system is proposed as a new index of bone quality for the evaluation of regenerated bone microstructure. Preferential alignment of the BAp c-axis in the rabbit ulna and skull bone, regenerated by controlled release of basic fibroblast growth factor (bFGF) was investigated. The BAp c-axis orientation was evaluated by the relative intensity between the (002) and (310) diffraction peaks, or the three-dimensional texture for the (002) peak. It was found that new bone in the defects was initially produced without preferential alignment of the BAp c-axis, and subsequently reproduced to recover towards the original alignment. In other words, the BAp density recovered prior to the BAp orientation. Perfect recovery of BAp alignment was not achieved in the ulna and skull defects after 4 weeks and 12 weeks, respectively. Apparent recovery of the macroscopic shape and bio-mineralization of BAp was almost complete in the ulna defect after 4 weeks. However, an additional 2 weeks was required for complete repair of BAp orientation. It is finally concluded that orientation distribution of BAp crystallites offers an effective means of evaluating the degree of microstructural regeneration, and also the related mechanical function, in regenerated hard tissues.

  2. The comparison of the band alignment of GaInAsN quantum wells on GaAs and InP substrates for (0 0 1) and (1 1 1) orientations

    NASA Astrophysics Data System (ADS)

    Köksal, K.; Gönül, B.

    2011-02-01

    The aim of this paper is to examine the effect of growth orientation and dilute nitride on the band alignment of GaInAs quantum wells on GaAs and InP substrates by means of model solid theory. The study provides a comparison of the band alignment and the strained band gap of the related GaInAsN QWs in (1 1 1) and (0 0 1) orientation. Our calculated results show that although 111-oriented GaInAsN QWs enables to reach the longer wavelengths, the conduction band offset gets shallow than that of the 001-oriented ones.

  3. The orientation of microdomains and the progression of shear alignment in block copolymer films: The roles of key material, film, and process parameters

    NASA Astrophysics Data System (ADS)

    Davis, Raleigh Lloyd

    Block copolymers provide attractive templates for nanopatterning at size scales inaccessible to conventional fabrication techniques. To serve effectively for most applications, however, the need to impart well-defined orientational and/or positional order to these microdomains is paramount. Shear alignment, has the powerful ability to macroscopically align microdomains in the direction of the applied shear simply by applying a stress at the film's surface. The primary goal of this dissertation is to investigate the influence of key material, film, and process parameters on the ease and quality of alignment in sheared block copolymer films. One important parameter which influences block copolymer thin film morphology is film thickness. To probe this effect rapidly and systematically, a film casting technique known as flowcoating was utilized. Previously, the quantitative relationship between the film thickness profile and the flowcoating process parameters was unclear. We illuminate this process by comparing experimental film thicknesses with a model based on a Landau-Levich treatment; the model thus provides a design approach which allows a user to produce polymer thin films of virtually any desired thickness profile. Via flowcoating, the influence of film thickness on block copolymer thin film morphology was then investigated using a series of polystyrene-poly(n-hexyl methacrylate) (PS-PHMA) diblocks varying in composition and molecular weight. The influence of additional material, film, and process parameters was then investigated using the same series of PS-PHMAs. To quantitatively compare the alignment process across the different block copolymer films, a melting-recrystallization model was fit to the data, which allowed for the determination of two key alignment parameters: the critical stress needed for alignment, and an orientation rate constant. Collectively, these results provide useful scaling rules which enable predictions of the level of alignment which

  4. The c-axis charge traveling wave in a coupled system of Josephson junctions

    NASA Astrophysics Data System (ADS)

    Shukrinov, Yu. M.; Hamdipour, M.

    2012-05-01

    We demonstrate a manifestation of the charge traveling wave along the c axis (TW) in current voltage characteristics of coupled Josephson junctions in high- T c superconductors. The branches related to the TW with different wavelengths are found for the stacks with different number of Josephson junctions at different values of system's parameters. Transitions between the TW branches and the outermost branch are observed. The electric charge in the superconducting layers and charge-charge correlation functions for TW and outermost branches show different behavior with bias current. We propose an experimental testing of the TW branching by microwave irradiation.

  5. Theoretical calculations of rotationally inelastic collisions of He with NaK(A {sup 1}Σ{sup +}): Transfer of population, orientation, and alignment

    SciTech Connect

    Malenda, R. F.; Price, T. J.; Stevens, J.; Uppalapati, S. L.; Fragale, A.; Weiser, P. M.; Kuczala, A.; Hickman, A. P.; Talbi, D.

    2015-06-14

    We have performed extensive calculations to investigate thermal energy, rotationally inelastic collisions of NaK (A{sup 1}Σ{sup +}) with He. We determined a potential energy surface using a multi-reference configuration interaction wave function as implemented by the GAMESS electronic structure code, and we have performed coupled channel scattering calculations using the Arthurs and Dalgarno formalism. We also calculate the Grawert coefficients B{sub λ}(j, j′) for each j → j′ transition. These coefficients are used to determine the probability that orientation and alignment are preserved in collisions taking place in a cell environment. The calculations include all rotational levels with j or j′ between 0 and 50, and total (translational and rotational) energies in the range 0.0002–0.0025 a.u. (∼44–550 cm{sup −1}). The calculated cross sections for transitions with even values of Δj tend to be larger than those for transitions with odd Δj, in agreement with the recent experiments of Wolfe et al. (J. Chem. Phys. 134, 174301 (2011)). The calculations of the energy dependence of the cross sections and the calculations of the fraction of orientation and alignment preserved in collisions also exhibit distinctly different behaviors for odd and even values of Δj. The calculations also indicate that the average fraction of orientation or alignment preserved in a transition becomes larger as j increases. We interpret this behavior using the semiclassical model of Derouard, which also leads to a simple way of visualizing the distribution of the angles between the initial and final angular momentum vectors j and j′. Finally, we compare the exact quantum results for j → j′ transitions with results based on the simpler, energy sudden approximation. That approximation is shown to be quite accurate.

  6. Synthesis and Characterization of High c-axis ZnO Thin Film by Plasma Enhanced Chemical Vapor Deposition System and its UV Photodetector Application.

    PubMed

    Chao, Chung-Hua; Wei, Da-Hua

    2015-10-03

    In this study, zinc oxide (ZnO) thin films with high c-axis (0002) preferential orientation have been successfully and effectively synthesized onto silicon (Si) substrates via different synthesized temperatures by using plasma enhanced chemical vapor deposition (PECVD) system. The effects of different synthesized temperatures on the crystal structure, surface morphologies and optical properties have been investigated. The X-ray diffraction (XRD) patterns indicated that the intensity of (0002) diffraction peak became stronger with increasing synthesized temperature until 400 (o)C. The diffraction intensity of (0002) peak gradually became weaker accompanying with appearance of (10-10) diffraction peak as the synthesized temperature up to excess of 400 (o)C. The RT photoluminescence (PL) spectra exhibited a strong near-band-edge (NBE) emission observed at around 375 nm and a negligible deep-level (DL) emission located at around 575 nm under high c-axis ZnO thin films. Field emission scanning electron microscopy (FE-SEM) images revealed the homogeneous surface and with small grain size distribution. The ZnO thin films have also been synthesized onto glass substrates under the same parameters for measuring the transmittance. For the purpose of ultraviolet (UV) photodetector application, the interdigitated platinum (Pt) thin film (thickness ~100 nm) fabricated via conventional optical lithography process and radio frequency (RF) magnetron sputtering. In order to reach Ohmic contact, the device was annealed in argon circumstances at 450 (o)C by rapid thermal annealing (RTA) system for 10 min. After the systematic measurements, the current-voltage (I-V) curve of photo and dark current and time-dependent photocurrent response results exhibited a good responsivity and reliability, indicating that the high c-axis ZnO thin film is a suitable sensing layer for UV photodetector application.

  7. Preferential orientation of biological apatite in normal and osteoporotic human vertebral trabeculae

    NASA Astrophysics Data System (ADS)

    Miyabe, S.; Ishimoto, T.; Nakano, T.

    2009-05-01

    The preferential orientation of biological apatite (BAp) is a possible bone quality parameter for the comparison of the bone mechanical property. The preferential BAp orientation undergoes sensitive changes according to the change in the in vivo stress distribution, bone turnover rate etc., resulting in a variation of bone function. Osteoporosis is a metabolic bone disease characterized by reduced bone mass and deterioration of bone microstructure. The effect of osteoporosis on the preferential BAp orientation is however unknown. In this study, a microbeam-X-ray diffraction (μXRD) study was carried out on a trabecula extracted from osteoporotic and normal human vertebral bones and the degree of orientation for the BAp c-axis along its craniocaudal axis was analysed based on our previous report. A micro-computed tomography (μCT) measurement was also performed to analyze trabecular density and structure. In osteoporotic human vertebra, the trabecular number is markedly lower than that in normal vertebra. To sustain increased stress because of bone loss, the primary trabeculae, which are aligned parallel to the craniocaudal axis, tend to selectively remain while the secondary trabeculae, which are perpendicular to the craniocaudal axis, mostly disappear. Moreover, the primary trabecula from osteoporotic vertebra showed a significantly higher degree of BAp preferential orientation than the normal bone. This suggests that the remaining primary trabecula in osteoporotic vertebra is further reinforced by an increase in applied stress in vivo by enhancing the preferred BAp c-axis orientation along the trabecular direction.

  8. Orientation-dependent energy level alignment and film growth of 2,7-diocty[1]benzothieno[3,2-b]benzothiophene (C8-BTBT) on HOPG.

    PubMed

    Lyu, Lu; Niu, Dongmei; Xie, Haipeng; Cao, Ningtong; Zhang, Hong; Zhang, Yuhe; Liu, Peng; Gao, Yongli

    2016-01-21

    Combining ultraviolet photoemission spectroscopy, X-ray photoemission spectroscopy, atomic force microscopy, and X-ray diffraction measurements, we performed a systematic investigation on the correlation of energy level alignment, film growth, and molecular orientation of 2,7-diocty[1]benzothieno[3,2-b]benzothiophene (C8-BTBT) on highly oriented pyrolytic graphite. The molecules lie down in the first layer and then stand up from the second layer. The ionization potential shows a sharp decrease from the lying down region to the standing up region. When C8-BTBT molecules start standing up, unconventional energy level band-bending-like shifts are observed as the film thickness increases. These shifts are ascribed to gradual decreasing of the molecular tilt angle about the substrate normal with the increasing film thickness.

  9. Orientation-dependent energy level alignment and film growth of 2,7-diocty[1]benzothieno[3,2-b]benzothiophene (C8-BTBT) on HOPG

    NASA Astrophysics Data System (ADS)

    Lyu, Lu; Niu, Dongmei; Xie, Haipeng; Cao, Ningtong; Zhang, Hong; Zhang, Yuhe; Liu, Peng; Gao, Yongli

    2016-01-01

    Combining ultraviolet photoemission spectroscopy, X-ray photoemission spectroscopy, atomic force microscopy, and X-ray diffraction measurements, we performed a systematic investigation on the correlation of energy level alignment, film growth, and molecular orientation of 2,7-diocty[1]benzothieno[3,2-b]benzothiophene (C8-BTBT) on highly oriented pyrolytic graphite. The molecules lie down in the first layer and then stand up from the second layer. The ionization potential shows a sharp decrease from the lying down region to the standing up region. When C8-BTBT molecules start standing up, unconventional energy level band-bending-like shifts are observed as the film thickness increases. These shifts are ascribed to gradual decreasing of the molecular tilt angle about the substrate normal with the increasing film thickness.

  10. The non-canonical role of vascular endothelial growth factor-C axis in cancer progression

    PubMed Central

    Wang, Chu-An

    2015-01-01

    It has been shown in many clinical studies that the level of vascular endothelial growth factor-C (VEGF-C) positively correlates with lymph node metastasis. Nevertheless, beyond the canonical role of VEGF-C in stimulating lymphangiogenesis and thus promoting lymph node/distant metastasis, emerging evidence indicates that expression of VEGF-C contributes to various aspects of carcinogenicity via autocrine regulation. The newly identified functions of VEGF-C include but are not limited to proliferation, migration, invasion, and chemo-resistance. Besides tumor cell autocrine regulation, VEGF-C can also modulate the immune system such that tumor cells more easily escape immune surveillance. Therefore, understanding the functional roles and regulatory mechanisms related to the VEGF-C axis may lead to alternative strategies for cancer treatment. This mini-review will focus on summarizing recent discoveries regarding the unconventional functions of VEGF-C in cancer progression. PMID:25888649

  11. Bilayer splitting and c-axis coupling in CMR bilayer manganites

    SciTech Connect

    Jozwiak, Chris; Graf, Jeff; Zhou, Shuyun; Bostwick, Aaron; Rotenberg, Eli; Zheng, Hong; Mitchell, John; Lanzara, Alessandra

    2009-09-03

    By performing angle-resolved photoemission spectroscopy of the bilayer colossal magnetoresistive (CMR) manganite, La2-2xSr1+2xMn2O7, we provide the complete mapping of the Fermi-level spectral weight topology. Clear and unambiguous bilayer splitting of the in-plane 3dx2-y2 band, mapped throughout the Brillouin zone, and the full mapping of the 3d3z2-r2 band are reported. Peculiar doping and temperature dependencies of these bands imply that as transition from the ferromagnetic metallic phase approaches, either as a function of doping or temperature, coherence along the c-axis between planes within the bilayer is lost, resulting in reduced interplane coupling. These results suggest that interplane coupling plays a large role in the CMR transition.

  12. Pulse-fluence-specified optimal control simulation with applications to molecular orientation and spin-isomer-selective molecular alignment

    SciTech Connect

    Yoshida, Masataka; Nakashima, Kaoru; Ohtsuki, Yukiyoshi

    2015-12-31

    We propose an optimal control simulation with specified pulse fluence and amplitude. The simulation is applied to the orientation control of CO molecules to examine the optimal combination of THz and laser pulses, and to discriminate nuclear-spin isomers of {sup 14}N{sub 2} as spatially anisotropic distributions.

  13. Direct synthesis of large-scale hierarchical MoS2 films nanostructured with orthogonally oriented vertically and horizontally aligned layers

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoyan; Zhang, Saifeng; Chen, Bohua; Wang, Hao; Wu, Kan; Chen, Yang; Fan, Jintai; Qi, Shen; Cui, Xiaoli; Zhang, Long; Wang, Jun

    2015-12-01

    Hierarchical MoS2 thin films nanostructured with orthogonally oriented vertically and horizontally aligned layers were designed and excellent passive Q-switching behavior in a fiber laser was demonstrated. A special solvothermal system containing a small amount of water was applied to synthesize such hierarchical MoS2 nanofilms, in which the reaction rate is carefully controlled by the diffusion rate of the sulfur precursor. Wafer-scale MoS2 thin films with hierarchical structures are formed on various substrates. Moreover, the hierarchical MoS2 thin films consisting of both vertical and horizontal layers can be tuned to possess only horizontally aligned layers by controlling the solvothermal time. To show the potential application proof-of-concept, the nonlinear optical performance of the hierarchical MoS2 was investigated. Superior passive Q-switching behavior in a fiber laser with a minimum pulse width of 2.2 μs was observed.Hierarchical MoS2 thin films nanostructured with orthogonally oriented vertically and horizontally aligned layers were designed and excellent passive Q-switching behavior in a fiber laser was demonstrated. A special solvothermal system containing a small amount of water was applied to synthesize such hierarchical MoS2 nanofilms, in which the reaction rate is carefully controlled by the diffusion rate of the sulfur precursor. Wafer-scale MoS2 thin films with hierarchical structures are formed on various substrates. Moreover, the hierarchical MoS2 thin films consisting of both vertical and horizontal layers can be tuned to possess only horizontally aligned layers by controlling the solvothermal time. To show the potential application proof-of-concept, the nonlinear optical performance of the hierarchical MoS2 was investigated. Superior passive Q-switching behavior in a fiber laser with a minimum pulse width of 2.2 μs was observed. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05938k

  14. Well-Aligned Arrays of Vertically Oriented ZnO Nanorod Films for Photocatalytic Degradation of Textile Dye

    NASA Astrophysics Data System (ADS)

    Nasr-Esfahani, Mojtaba; Nekoubin, Amin

    2011-05-01

    Well-aligned hexagonal ZnO nanorods arrays were synthesized via mild hydrothermal method under different conditions. A two-step approach was employed for the epitaxial growth of ZnO. First a ZnO seed layer was prepared by spin-coating process and then ZnO nanorods were deposited on it. The influences of growth time on the surface morphology, length, diameters and phase structure of ZnO rods films were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photocatalytic degradation of X6G an anionic monoazo dye, in aqueous solutions, was investigated and the effects of hydrothermal process time were examined. The results showed that the ZnO nonorods film hydrothermal treated for 4 h have a very high photocatalytic performance.

  15. Interfacial band alignment and structural properties of nanoscale TiO{sub 2} thin films for integration with epitaxial crystallographic oriented germanium

    SciTech Connect

    Jain, N.; Zhu, Y.; Hudait, M. K.; Maurya, D.; Varghese, R.; Priya, S.

    2014-01-14

    We have investigated the structural and band alignment properties of nanoscale titanium dioxide (TiO{sub 2}) thin films deposited on epitaxial crystallographic oriented Ge layers grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy. The TiO{sub 2} thin films deposited at low temperature by physical vapor deposition were found to be amorphous in nature, and high-resolution transmission electron microscopy confirmed a sharp heterointerface between the TiO{sub 2} thin film and the epitaxially grown Ge with no traceable interfacial layer. A comprehensive assessment on the effect of substrate orientation on the band alignment at the TiO{sub 2}/Ge heterointerface is presented by utilizing x-ray photoelectron spectroscopy and spectroscopic ellipsometry. A band-gap of 3.33 ± 0.02 eV was determined for the amorphous TiO{sub 2} thin film from the Tauc plot. Irrespective of the crystallographic orientation of the epitaxial Ge layer, a sufficient valence band-offset of greater than 2 eV was obtained at the TiO{sub 2}/Ge heterointerface while the corresponding conduction band-offsets for the aforementioned TiO{sub 2}/Ge system were found to be smaller than 1 eV. A comparative assessment on the effect of Ge substrate orientation revealed a valence band-offset relation of ΔE{sub V}(100) > ΔE{sub V}(111) > ΔE{sub V}(110) and a conduction band-offset relation of ΔE{sub C}(110) > ΔE{sub C}(111) > ΔE{sub C}(100). These band-offset parameters are of critical importance and will provide key insight for the design and performance analysis of TiO{sub 2} for potential high-κ dielectric integration and for future metal-insulator-semiconductor contact applications with next generation of Ge based metal-oxide field-effect transistors.

  16. Charge Dynamics of 2H- TaSe2 along the Less-Conducting c-Axis

    NASA Astrophysics Data System (ADS)

    Ruzicka, B.; Degiorgi, L.; Berger, H.; Gaál, R.; Forró, L.

    2001-04-01

    We present an optical study of 2H-TaSe2 along the less conducting c-axis. This dichalcogenide compound belongs to a large class of conductors called ``bad metals'' (with a mean free path smaller than the lattice constant along the c-axis), which also includes the superconducting cuprates. The optical response shows the progressive development of a pseudogaplike feature with decreasing temperature. The spectral weight lost by the opening of such a pseudogap goes into the narrow Drude component, developing at low frequency and temperature. There is no violation of the sum rule in 2H-TaSe2 contrary to the cuprates.

  17. Deformation thermometry based on quartz c-axis fabrics and recrystallization microstructures: A review

    NASA Astrophysics Data System (ADS)

    Law, Richard D.

    2014-09-01

    For quartz-rich tectonites two types of deformation thermometer are currently commonly employed: 1) The quartz c-axis fabric opening-angle thermometer that provides an estimate of deformation temperatures when fabrics were ‘locked in' during dislocation creep and dynamic recrystallization. 2) The quartz recrystallization thermometer that indicates a range of likely deformation temperatures based on observed microstructures and inferred mechanisms of dynamic recrystallization. A critically important caveat in applying both thermometers is the assumption that deformation temperature is the primary controlling factor in recrystallization mechanisms and fabric development. However, fabric opening-angles and recrystallization mechanisms are also sensitive to other variables such as strain rate and water weakening. In this paper the development of these thermometers is reviewed, and their potential sensitivities to competing factors such as temperature, strain rate, water weakening and (in the case of opening-angles) 3D strain type are discussed. Examples of the application of these potential thermometers to naturally deformed quartz-rich rocks are given, and case studies of correlations between deformation temperatures estimated by these thermometers and temperatures of synkinematic metamorphism determined by petrology-based thermobarometers are highlighted. In the review, attention is focused on problems associated with applying these thermometers to natural deformation, and examples of such problems are discussed.

  18. In situ Pulsed Laser Deposition of C-Axis Oriented MgB2 Films and Their Characterization

    NASA Technical Reports Server (NTRS)

    Shinde, Sanjay; Lakew, Brook; Ogale, S. B.; Kulkarni, V. N.; Kale, S. N.; Venkatesan, T.

    2004-01-01

    The recent discovery of an intermetallic superconductor MgB2 has renewed interest in the area of superconductivity not only because of fundamental understanding of superconductivity but also due to its potential applicability in devices such as thermal detectors. Considerable amount of research has been devoted to obtain MgB2 films by an all in situ growth technique. We have grown MgB2 thin films by an all in situ pulsed laser deposition process from pure B and Mg targets. Ultrathin layers of B and Mg were deposited in a multilayer configuration. Hundreds of such Mg-B bilayers with a capping Mg layer on the top were deposited on sapphire substrate. These depositions were done in high vacuum (approx. 10(exp -7) Torr) and at room temperature. After deposition, such a configuration was annealed at high temperature for a short time in a forming gas (4% H2 in Ar). The best films, obtained by this procedure, showed superconducting transition temperature approx. 30 K. These films have been characterized by x-ray diffraction, Rutherford Backscattering Spectrometry, AC susceptibility-, resistivity- (with and without magnetic field) and 1/f noise-measurements. The physical properties of these films will be presented and discussed.

  19. Neutron diffraction texture analysis for α-Al2O3 oriented by high magnetic field and sintering

    NASA Astrophysics Data System (ADS)

    Terada, N.; Suzuki, H. S.; Suzuki, T. S.; Kitazawa, H.; Sakka, Y.; Kaneko, K.; Metoki, N.

    2009-05-01

    We have performed neutron diffraction experiments on highly oriented α-Al2O3, obtained by slip casting under a magnetic field and sintering. In order to investigate the magnetic field, B, and sintering temperature, Tsint, dependence of the degree of alignment of the orientation, we used samples treated with systematically varied B up to 12 T and Tsint up to 1600 °C. The degree of alignment of the magnetic easy axis (the hexagonal c-axis) is rapidly enhanced by sintering above 1200 °C, which is coincident with the temperature at which crystal grains start to grow. The angular distribution of the c-axis for the sample sintered at 1600 °C, obtained by ω-scan neutron diffraction profiles, is almost coincident with the probability distribution calculated for the particle size two times larger than that in the starting material. We discuss the orientation process mechanism with sintering in light of the results of this analysis.

  20. Origin of the c-axis ultraincompressibility of Mo2GaC above about 15 GPa from first principles

    NASA Astrophysics Data System (ADS)

    Qing-He, Gao; Zhi-Jun, Xu; Ling, Tang; Jin, Li; An, Du; Yun-Dong, Guo; Ze-Jin, Yang

    2016-01-01

    The mechanical properties and structural evolution of Mo2GaC are calculated by first-principles under pressure. Our results unexpectedly found that the c axis is always stiffer than a axis within 0-100 GPa. An ultraincompressibility of c axis within 15-60 GPa is observed, with a contraction of about 0.2 Å, slightly larger than that of a axis (0.14 Å). The abnormal expansion of c axis and the fast decrease in a axis above about 15 GPa and 70 GPa failed to induce the structural instability, whereas such behavior caused the elastic softening in many mechanical quantities. The shrinkage anomaly of c axis is closely reflected by the internal coordinate (u) shift of Mo atom as it shows three different slopes within 0-15 GPa, 20-60 GPa, and 70-100 GPa, respectively. The longest Mo-Mo bond is responsible for the unusual shrinkage of c-axis under pressure as they experience nearly identical pressure dependences, whereas the a axis presents certain response with the variation of C-Mo bond particularly at 70 GPa. The electronic properties are investigated, including the energy band and density of states, and so on. At G point of K-M line, the energy decreases at 10 GPa first and increases at 30 GPa subsequently, the critical point is at about 15 GPa, with respective values of -0.17 of 0 GPa, -0.18 of 10 GPa, -0.16 of 15 GPa, and -0.13 of 30 GPa, respectively. This alternative energy change of G point, which is the symmetry center of the rhombic parallelogram of Ga atoms and the midpoint of the two bonded Mo atoms, convincingly reveal the origin of the anomalous ultraincompressibility of c axis as the Mo-Mo bond length shrinkage has to overcome the increasing energy barrier height. The Mo-Mo bond population and the electronegativity investigations of the Mo atom further reveal the most likely origin of the ultraincompressibility of c axis. This interesting result expects further experimental confirmation as this is the first nanolaminate ceramics compound presenting quite

  1. A new empirical calibration of the quartz c-axis fabric opening-angle deformation thermometer

    NASA Astrophysics Data System (ADS)

    Faleiros, F. M.; Moraes, R.; Pavan, M.; Campanha, G. A. C.

    2016-03-01

    The opening-angle of quartz c-axis fabrics (OA) is strongly temperature dependent and has proven to be a powerful deformation thermometer for natural metamorphic rocks. Previous considerations of empirical data have identified a linear correlation between OA and temperature between 250 and 650 °C, and no correlation above 650 °C. However, possible effects of pressure have not been investigated. We expanded the data set of OA versus temperature, including data from rocks deformed over 300-1050 °C and 2.5-15 kbar. Disregarding possible effects of pressure, the OA-temperature relationship can be described by two linear correlations for the intervals ~ 250-650 °C and ~ 650-1050 °C: The change on the curve slope of the OA-temperature relationship correlates approximately to the low- to high-quartz transition and to changes in the dynamic recrystallization mechanism from subgrain rotation to grain boundary migration. The available data suggest that pressure has a secondary effect accompanying the major temperature dependence of OA, which is particularly important for temperatures above 650 °C, where the correlation between OA and temperature is less pronounced. For fixed pressures, the OA has logarithmic relationships with temperature over the range 250-1050 °C. The following thermometer equation is formulated from a multiple regression: An uncertainty of ± 50 °C is inherited from the petrological temperature estimates of the natural samples. The data suggest the gradual increasing importance of prism [c] slip relative to < a > slip in quartz with rising temperature. Under conditions of 'average' geological strain rate and water weakening, prism [c] slip dominates for deformation above ~ 700 °C.

  2. Abnormal arrangement of a collagen/apatite extracellular matrix orthogonal to osteoblast alignment is constructed by a nanoscale periodic surface structure.

    PubMed

    Matsugaki, Aira; Aramoto, Gento; Ninomiya, Takafumi; Sawada, Hiroshi; Hata, Satoshi; Nakano, Takayoshi

    2015-01-01

    Morphological and directional alteration of cells is essential for structurally appropriate construction of tissues and organs. In particular, osteoblast alignment is crucial for the realization of anisotropic bone tissue microstructure. In this article, the orientation of a collagen/apatite extracellular matrix (ECM) was established by controlling osteoblast alignment using a surface geometry with nanometer-sized periodicity induced by laser ablation. Laser irradiation induced self-organized periodic structures (laser-induced periodic surface structures; LIPSS) with a spatial period equal to the wavelength of the incident laser on the surface of biomedical alloys of Ti-6Al-4V and Co-Cr-Mo. Osteoblast orientation was successfully induced parallel to the grating structure. Notably, both the fibrous orientation of the secreted collagen matrix and the c-axis of the produced apatite crystals were orientated orthogonal to the cell direction. To the best of our knowledge, this is the first report demonstrating that bone tissue anisotropy is controllable, including the characteristic organization of a collagen/apatite composite orthogonal to the osteoblast orientation, by controlling the cell alignment using periodic surface geometry.

  3. Alignment-to-orientation conversion in a magnetic field at nonlinear excitation of the D2 line of rubidium: Experiment and theory

    NASA Astrophysics Data System (ADS)

    Auzinsh, M.; Berzins, A.; Ferber, R.; Gahbauer, F.; Kalvans, L.; Mozers, A.; Spiss, A.

    2015-05-01

    We studied alignment-to-orientation conversion caused by excited-state level crossings in a nonzero magnetic field of both atomic rubidium isotopes. Experimental measurements were performed on the transitions of the D2 line of rubidium. These measured signals were described by a theoretical model that takes into account all neighboring hyperfine transitions, the mixing of magnetic sublevels in an external magnetic field, the coherence properties of the exciting laser radiation, and the Doppler effect. In the experiments, laser-induced fluorescence components were observed at linearly polarized excitation and their difference was taken afterwards. By observing the two oppositely circularly polarized components, we were able to see structures not visible in the difference graphs, which give deeper insight into the processes responsible for these signals. We studied how these signals are dependent on intensity and how they are affected when the exciting laser is tuned to different hyperfine transitions. The comparison between experiment and theory was carried out fulfilling the nonlinear absorption conditions. The theoretical curves described the experimental measurements satisfactorily, reproducing even small features in the shapes of the curves.

  4. Orientational coupling between the vortex lattice and the crystalline lattice in a weakly pinned Co0.0075NbSe2 single crystal

    NASA Astrophysics Data System (ADS)

    Ganguli, Somesh Chandra; Singh, Harkirat; Ganguly, Rini; Bagwe, Vivas; Thamizhavel, Arumugam; Raychaudhuri, Pratap

    2016-04-01

    We report experimental evidence of strong orientational coupling between the crystal lattice and the vortex lattice in a weakly pinned Co-doped NbSe2 single crystal through direct imaging using low temperature scanning tunneling microscopy/spectroscopy. When the magnetic field is applied along the six-fold symmetric c-axis of the NbSe2 crystal, the basis vectors of the vortex lattice are preferentially aligned along the basis vectors of the crystal lattice. The orientational coupling between the vortex lattice and crystal lattice becomes more pronounced as the magnetic field is increased. This orientational coupling enhances the stability of the orientational order of the vortex lattice, which persists even in the disordered state at high fields where dislocations and disclinations have destroyed the topological order. Our results underpin the importance of crystal lattice symmetry on the vortex state phase diagram of weakly pinned type II superconductors.

  5. Effects of c-axis Josephson coupling on dissipation, flux dynamics and the mechanism of high-T{sub c} superconductivity

    SciTech Connect

    Gray, K.E.; Hettinger, J.D.

    1995-12-31

    Measurements of the c-axis transport in highly anisotropic HTS materials strongly indicate that Josephson coupling is involved. This conclusion affects various properties of the HTS cuprates, including the irreversibility behavior for transport in the ab planes, the direct c-axis transport and potentially the mechanism of Cooper pairing.

  6. Charge-screening role of c -axis atomic displacements in YBa2Cu3O6 +x and related superconductors

    NASA Astrophysics Data System (ADS)

    Božin, E. S.; Huq, A.; Shen, Bing; Claus, H.; Kwok, W. K.; Tranquada, J. M.

    2016-02-01

    The importance of charge reservoir layers for supplying holes to the CuO2 planes of cuprate superconductors has long been recognized. Less attention has been paid to the screening of the charge transfer by the intervening ionic layers. We address this issue in the case of YBa2Cu3O6 +x , where CuO chains supply the holes for the planes. We present a simple dielectric-screening model that gives a linear correlation between the relative displacements of ions along the c axis, determined by neutron powder diffraction, and the hole density of the planes. Applying this model to the temperature-dependent shifts of ions along the c axis, we infer a charge transfer of 5-10% of the hole density from the planes to the chains on warming from the superconducting transition to room temperature. Given the significant coupling of c -axis displacements to the average charge density, we point out the relevance of local displacements for screening charge modulations and note recent evidence for dynamic screening of in-plane quasiparticles. This line of argument leads us to a simple model for atomic displacements and charge modulation that is consistent with images from scanning-tunneling microscopy for underdoped Bi2Sr2CaCu2O8 +δ .

  7. Uniaxial drawing of poly[(R)-3-hydroxybutyrate]/cellulose acetate butyrate blends and their orientation behavior.

    PubMed

    Park, Jun Wuk; Tanaka, Toshihisa; Doi, Yoshiharu; Iwata, Tadahisa

    2005-09-16

    Miscible blends of PHB and CAB were prepared by the solvent-casting method with various blend compositions, and their orientation behavior was investigated during uniaxial drawing. X-ray analysis revealed that the orientation of the crystallizable PHB component in the drawn PHB/CAB blends was changed from c-axis-orientation to a-axis-orientation with increasing CAB content. The a-axis-orientation was a result from the a-axis-oriented crystal growth caused by the intramolecular nucleation and the confined crystal growth. For quantitative assessment of the chain orientation, the Hermans orientation functions of the two respective components were obtained from the polarized FT-IR measurements. The orientation function of pure PHB stretched to 5 times of its initial length was approximately 0.8. However the value decreased rapidly with increasing CAB content, and it turned to a negative value from 30 wt.-% CAB content. This indicates that the PHB chains were aligned perpendicular to the drawing direction. On the contrary, the value of the CAB component remained almost unchanged at about 0.1 regardless of the blend composition and the annealing time, indicating that the CAB chains were constantly oriented parallel to the drawing direction without any chain relaxation. In addition, SAXS analysis suggested that the lamellar stacking direction also changed from parallel to perpendicular in the stretching direction with increasing CAB content.

  8. Atomic Alignment Effects for the Formation of Excimers RgX* (B, C) in the Reaction of Oriented Rg (3P2, MJ = 2) (Rg = Xe, Kr, Ar) + Halogen(X)-Containing Molecules

    NASA Astrophysics Data System (ADS)

    Ohoyama, H.; Yasuda, K.; Kasai, T.

    2009-07-01

    Atomic alignment effects for the formation of excimers, RgX* (B, Ω = 1/2) and RgX* (C, Ω = 3/2), in the reaction of Rg (3P2) (Rg = Xe, Kr, Ar) with halogen (X)-containing molecules (RX) (CH3I, CF3I, CF3Br, NF3, CHBr3, CHCl3, CCl3F, and CCl4) have been measured by using an oriented Rg (3P2, MJ = 2) atomic beam at a collision energy of ˜0.07 eV. The emission intensities for RgX* (B, C) have been measured as a function of the magnetic orientation field direction in the collision frame. The reactant (RX) dependence of the atomic alignment effect is extremely different between the RgX* (B) and the RgX* (C) channels. For RgX* (C), an analogous atomic alignment effect is commonly observed despite the difference of RX and Rg. In contrast, for RgX* (B), the atomic alignment effect shows a diverse dependence on RX and Rg.

  9. Implementing Strategic Orientation

    ERIC Educational Resources Information Center

    Fischer, Arthur K.; Brownback, Sarah

    2012-01-01

    An HRM case dealing with problems and issues of setting up orientation programs which align with corporate strategy. Discussion concerns how such a case can be used to exhibit the alignment between HRM and business strategy.

  10. Variation of critical current and n-value of 2G HTS tapes in external magnetic fields of different orientation

    NASA Astrophysics Data System (ADS)

    Sychugov, V. V.; Degtyarenko, P. N.; Ovcharov, A. V.; Shavkin, S. V.; Kruglov, V. S.; Vasiliev, A. L.; Volkov, P. V.; Chesnokov, Yu M.

    2016-09-01

    The in-field orientation dependence of critical current and n-value in second generation high temperature superconductive tapes was investigated. The samples were manufactured by Metalorganic Chemical Vapour Deposition method with BaZrO3 inclusions (SuperPower Inc.) and Pulsed Laser Deposition method (Bruker HTS). For samples of each kind of fabrication techniques we observed higher critical current value in the case of external magnetic field aligned along (or nearby) c-axis direction in comparison with one aligned along ab-plane. We analysed possible reasons for this effect. Angular dependences of the critical current and n-value were investigated. The microstructure images of superconductive layer of studied samples show tilt of BaZrO3 nanorods in MOCVD sample and high density of structural defects for PLD sample.

  11. Characterization of tin crystal orientation evolution during thermal cycling in lead-free solder joints

    NASA Astrophysics Data System (ADS)

    Zhou, Bite

    To address the long term reliability of lead-free solder joints in electronic devices during thermal cycling, the fundamental understanding of deformation mechanisms was studied using polarized light optical microscopy (PLM), electron backscatter diffraction (EBSD) in scanning electron microscopy (SEM), and synchrotron X-ray diffraction (XRD). Near-eutectic Sn-3.0(wt %) Ag-0.5(wt %) Cu (SAC305) lead-free solder joints were assessed in three different package designs: low-strain plastic ball grid array (PBGA), medium-strain fine-pitch ball grid array (BGA), and high-strain wafer-level-chip-scale package (WLCSP). The effect of microstructure evolution on solder failure is correlated with dislocation slip activities. The major failure mode in lead-free solder joints during thermal cycling that causes the electrical failure of the device is cracking in the bulk Sn near the Si chip/solder interface. Microstructure and Sn grain orientation evolution usually precedes crack development. A combined approach of both statistical analysis of a large number of solder joints, and detailed studies of individual solder balls was used to investigate the causes of fracture. Sn crystal orientation evolution and its effect on deformation was characterized in solder joints with different thermal histories, and compared with those from other package designs with different effective strain levels. The relationship between the initial dominant and localized recrystallized Sn grain orientations on crack development was investigated. It is found that in the low-strain package design, cracking is strongly correlated with Sn grain orientations with the [001] direction (c-axis) nearly aligned with the chip/solder interface. But no cracks were observed in solder balls with dominant orientations that have the c-axis normal to the interface plane. In higher-strain packages, however, cracking occurred in a variety of Sn grain orientations, and even solder balls with dominant orientations that are

  12. Ice crystals growing on K-feldspar (microcline) have preferential orientation dictated by feldspar lattice structure

    NASA Astrophysics Data System (ADS)

    Kiselev, A. A.; Bachmann, F.; Pedevilla, P.; Cox, S.; Michaelides, A.

    2014-12-01

    Recently, we have conducted experiments on deposition nucleation and growth of ice on freshly cleaved natural K-feldspar (microcline) crystals exposed to water vapor in the Environmental Scanning Electron Microscope (ESEM, FEI Quanta 650 FEG). Independently adjusting the partial water vapor pressure in the sample chamber and the temperature of the substrate mounted on top of the double-stage Peltier element, deposition ice nucleation, growth, and sublimation can be studied within the temperature range from -5°C to -60°C. By using small crystal size and tilted geometry we have been able to record the video sequences of ice nucleation taking place on both 001 and 010 crystallographic planes simultaneously. Here, we report the following general features of ice nucleation and growth observed in these experiments: Nucleation of ice always starts before the water saturation is reached. Ice was preferentially nucleating on surface defects (steps, cracks, and pits) or on the debris particles scattered over the surface of feldspar crystal. Ice crystals grown via deposition at temperatures above -30°C on any of the feldspar crystal faces have shown the same directional and rotational orientation, with c-axis of ice aligned with the c-axis of microcline unit cell. Below -35°C no preferential orientation has been observed whatsoever. The majority of observed ice crystals exhibit the evaporation groove at the waist of hexagonal prism, indicting the presence of lattice dislocations in the crystal nucleation plane. We discuss a possible mechanism of crystal lattice alignment by considering layer of ordered water on the surface of feldspar crystal forming prior to ice nucleation. Using density functional theory we show how the mineral surface interacts with water, particularly addressing the interaction of surface cations and hydroxyl groups with a water overlayer. We argue that the misalignment of the 001 lattice planes for microcline and ice (inherently following from the

  13. Incoherent c-Axis Interplane Response of the Iron Chalcogenide FeTe0:55Se0:45 Superconductor from Infrared Spectroscopy

    SciTech Connect

    Gu, G.D.; Moon, S.J.; Homes, C.C.; Akrap, A.; Xu,, Z.J.; Wen, J.S.; Lin,, Z.W.; Li, Q.; Basov, D.N.

    2011-05-23

    We report on the interplane c-axis electronic response of FeTe{sub 0.55}Se{sub 0.45} investigated by infrared spectroscopy. We find that the normal-state c-axis electronic response of FeTe{sub 0.55}Se{sub 0.45} is incoherent and bears significant similarities to those of mildly underdoped cuprates. The c-axis optical conductivity {sigma}{sub c}({omega}) of FeTe{sub 0.55}Se{sub 0.45} does not display well-defined Drude response at all temperatures. As temperature decreases, {sigma}{sub c}({omega}) is continuously suppressed. The incoherent c-axis response is found to be related to the strong dissipation in the ab-plane transport: a pattern that holds true for various correlated materials as well as FeTe{sub 0.55}Se{sub 0.45}.

  14. Far infrared video detection and difference frequency mixing with tilted c-axis epitaxial YBa2Cu3O7 - delta thin films

    NASA Astrophysics Data System (ADS)

    Huber, W. M.; Berr, M.; Kalbeck, A.; Prettl, W.; Huggard, P. G.

    1996-06-01

    Epitaxial YBa2Cu3O7-δ thin films, grown with a controllable misalignment between c-axis and surface normal, exhibit a sensitive photoresponse to far infrared laser radiation at temperatures below Tc. While no photoresponse was observed in c-axis normal films, a sensitivity of 0.2 V/W was measured at a wavelength of 432 μm for a film with a 20° c-axis tilt. Difference frequency mixing of two laser modes has also been demonstrated at intermediate frequencies between 200 kHz and 6 MHz. Both mixing and video detection are believed to originate in the ac Josephson effect: the effect of the tilted growth is to allow a component of the radiation field to be applied along the c-axis, thus modulating the relatively weak Josephson coupling in this direction.

  15. Effect of spin fluctuations on the c-axis thermoelectric power in underdoped La2- xSrxCuO4+δ

    NASA Astrophysics Data System (ADS)

    Ping, Lou

    2001-04-01

    A theory of the thermoelectric power due to the competition between interlayer direct hopping and the hopping assisted by the spin fluctuations has been developed. The prediction of the theory captures the main feature of experiment. Thus we argue that the c-axis thermoelectric power exhibits metallic behavior while the c-axis electronic conductivity appears to be nonmetallic in the underdoped LaSrCuO and may be properly understood within the theory.

  16. Atomic alignment effect on reactivity and on product alignment in the energy-transfer reaction of oriented Ar (3P2, 4s [3/2]2, M(J) = 2) + Kr (4p6, 1S0) → Ar (3p6, 1S0) + Kr (5p [3/2]2).

    PubMed

    Ohoyama, H

    2015-03-12

    Steric effect for the formation of Kr (5p [3/2]₂) in the energy transfer reaction of Ar (³P₂, 4s [3/2]₂) + Kr has been studied by using an oriented Ar (³P₂, 4s [3/2]₂, M(J) = 2) beam at a collision energy of ∼0.09 eV. The emission intensity of Kr (5p [3/2]₂) is ca. 2 times enhanced when the angular momentum (J(Ar)) of Ar (³P₂) is aligned perpendicular to the relative velocity vector (v(R)). In addition, the Kr (5p [3/2]₂) emission is highly polarized parallel to v(R) (I(∥)/I(⊥) ∼ 1.2) when JAr is aligned perpendicular to v(R). The observed polarization moments indicate that the alignment of the unpaired Ar (3p) orbital of Ar (³P₂) to v(R), (Σ (|L′| = 0), Π (|L′| = 1)), dominates the energy transfer probability (σ(Π)(∥): σ(Σ)(∥): σ(Π)(⊥): σ(Σ)(⊥) = 0.49:1.33:0.55:1.23) and also the alignment of the Kr (5p) orbital of Kr (5p [3/2]₂) to v(R): the Σ-configuration of the Ar (3p) orbital leads to the parallel alignment (Σ-configuration) of the Kr(5p) orbital to v(R), conversely, the Π-configuration of Ar (3p) orbital leads to the perpendicular alignment (Π-configuration) of the Kr(5p) orbital. In addition, the selectivity of the alignment of the Kr (5p) orbital turns out to vary from perpendicular to parallel as the collision energy increases after a threshold down to 0.03 eV.

  17. Inducing uniform single-crystal like orientation in natural rubber with constrained uniaxial stretch.

    PubMed

    Zhou, Weiming; Meng, Lingpu; Lu, Jie; Wang, Zhen; Zhang, Wenhua; Huang, Ningdong; Chen, Liang; Li, Liangbin

    2015-07-01

    The effect of flow on crystallization is commonly attributed to entropic reduction, which is caused by stretch and orientation of polymer chains but overlooks the role of flow on final-state free energy. With the aid of in situ synchrotron radiation wide-angle X-ray diffraction (WAXD) and a homemade constrained uniaxial tensile testing machine, polycrystals possessing single-crystal-like orientation rather than uniaxial orientation are found during the constrained stretch of natural rubber, whereas the c-axis and a-axis align in the stretch direction (SD) and constrained direction (CD), respectively. Molecular dynamics simulation shows that aligning the a-axis of crystal nuclei in CD leads to the lowest free energy increase and favors crystal nucleation. This indicates that the nomenclature of strain-induced crystallization may not fully account for the nature of flow-induced crystallization (FIC) as strain mainly emphasizes the entropic reduction of initial melt, whereas stress rather than strain plays the dominant role in crystal deformation. The current work not only contributes to a comprehensive understanding of the mechanism of flow-induced crystallization but also demonstrates the potential application of constrained uniaxial tensile stretch for the creation of functional materials containing polycrystals that possess single-crystal-like orientation.

  18. rf surface resistance of a magnetically aligned sintered pellet of YBa2Cu3O7

    NASA Astrophysics Data System (ADS)

    Padamsee, H.; Kirchgessner, J.; Moffat, D.; Rubin, D.; Shu, Q. S.; Hart, H. R.; Gaddipati, A. R.

    1990-02-01

    rf (radio frequency) properties of polycrystalline ceramic material are substantially inferior to those of the best microtwinned crystals. At 6 GHz and 77 K, the best surface resistance values for ceramics are ˜20 mΩ, compared to <0.5 mΩ for high-quality crystals. The microwave resistance is observed to increase at higher rf fields for ceramics, e.g., two orders of magnitude between 0.1 and 10 Oe, but remains low for crystals. A possible reason for the inferior properties in randomly oriented polycrystalline ceramics is related to the anisotropy of the superconducting properties; crystals aligned unfavorably with the sampling rf field could be responsible for the high resistance. Another possibility is related to the difficulty of carrying current across the grain boundaries due to weak links arising from second phases, impurities, cracks, etc., at the boundaries. To elucidate the contribution from these two potential problem sources, we have measured the rf properties at 6 GHz of an oriented polycrystalline ceramic pellet prepared from a suspension of high purity powder in a 4-T magnetic field. Samples were characterized by x-ray diffraction, light microscopy, transmission electron microscopy, x-ray rocking curves, and x-ray pole figure studies, indicating a high degree of alignment, although not as complete as in epitaxial thin films. At liquid He temperature, the surface resistance is 28 times lower when the c axis is perpendicular to the plane in which rf currents flow than when the c axis is in the plane. At 77 K, the surface resistance is 3 mΩ, a significant improvement over the properties of the best randomly oriented material reported. At 4 K the resistance improves to 0.3 mΩ. These resistances were all measured with rf fields below 0.1 Oe, but increased by one order of magnitude when the rf field was increased to 10 Oe, as in the polycrystalline material. Our results indicate that while the low-field rf behavior is strongly improved by orientation

  19. Temperature dependent c-axis hole mobilities in rubrene single crystals determined by time-of-flight

    NASA Astrophysics Data System (ADS)

    Pundsack, Tom J.; Haugen, Neale O.; Johnstone, Lucas R.; Daniel Frisbie, C.; Lidberg, Russell L.

    2015-03-01

    Hole mobilities (μ) in rubrene single crystals (space group Cmca) along the crystallographic c-axis have been investigated as a function of temperature and applied electric field by the time-of-fight method. Measurements demonstrate an inverse power law dependence on temperature, namely, μ=μ0T-n with n = 1.8, from room temperature down to 180 K. At 296 K, the average value of μ was found to be 0.29 cm2/Vs increasing to an average value of 0.70 cm2/Vs at 180 K. Below 180 K a decrease in mobility is observed with further cooling. Overall, these results confirm the anisotropic nature of transport in rubrene crystals as well as the generality of the inverse power law temperature dependence that is observed for field effect mobility measurements in the a-b crystal plane.

  20. Nanosecond laser switching of surface wettability and epitaxial integration of c-axis ZnO thin films with Si(111) substrates.

    PubMed

    Molaei, R; Bayati, M R; Alipour, H M; Estrich, N A; Narayan, J

    2014-01-01

    We have achieved integration of polar ZnO[0001] epitaxial thin films with Si(111) substrates where cubic yttria-stabilized zirconia (c-YSZ) was used as a template on a Si(111) substrate. Using XRD (θ-2θ and φ scans) and HRTEM techniques, the epitaxial relationship between the ZnO and the c-YSZ layers was shown to be [0001]ZnO || [111]YSZ and [21¯1¯0]ZnO || [1¯01](c-YSZ), where the [21¯1¯0] direction lies in the (0001) plane, and the [1¯01] direction lies in the (111) plane. Similar studies on the c-YSZ/Si interface revealed epitaxy as (111)YSZ || (111)Si and in-plane (110)YSZ || (110)Si. HRTEM micrographs revealed atomically sharp and crystallographically continuous interfaces. The ZnO epilayers were subsequently laser annealed by a single pulse of a nanosecond excimer KrF laser. It was shown that the hydrophobic behavior of the pristine sample became hydrophilic after laser treatment. XPS was employed to study the effect of laser treatment on surface stoichiometry of the ZnO epilayers. The results revealed the formation of oxygen vacancies, which are envisaged to control the observed hydrophilic behavior. Our AFM studies showed surface smoothing due to the coupling of the high energy laser beam with the surface. The importance of integration of c-axis ZnO with Si(111) substrates is emphasized using the paradigm of domain matching epitaxy on the c-YSZ[111] buffer platform along with their out-of-plane orientation, which leads to improvement of the performance of the solid-state devices. The observed ultrafast response and switching in photochemical characteristics provide new opportunities for application of ZnO in smart catalysts, sensors, membranes, DNA self-assembly and multifunctional devices.

  1. Orientation features of {sup 24}Mg(2+) aligned nuclei in (p, p) and (d, d) reactions at E{sub x} ≈ 7.5 MeV per nucleon

    SciTech Connect

    Galanina, L. I. Zelenskaya, N. S.; Lebedev, V. M.; Orlova, N. V.; Spassky, A. V.

    2015-09-15

    Experimental angular dependences of cross sections for elastic and inelastic scattering and the result obtained by reconstructing the populations of magnetic sublevels, multipole-moment orientation tensors, and polarization tensors are presented for {sup 24}Mg (2{sup +}, 1.369 MeV) aligned nuclei produced in inelastic proton scattering at E{sub p} = 7.4 MeV. The experimental results in question are compared with the results of calculations based on the coupled-channel method and on the compound-nucleus model, the 3/2{sup +} resonance in the {sup 25}Al compound nucleus being taken into account. The orientation features of {sup 24}Mg (2{sup +}, 1.369 MeV) nuclei produced in inelastic proton and deuteron scattering on {sup 24}Mg at E{sub x} ≈ 7.5 MeV per nucleon are found to be generally similar despite a substantial difference in the respective differential cross sections.

  2. Fabrication and characteristics of weak links between {cflx {ital a}} and {cflx {ital c}}-axis normal grains of Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}}

    SciTech Connect

    Mahajan, S.; Buchholz, D.B.; Lei, J.; Chang, R.P.; Hogan, T.; Kannewurf, C.R.; Song, S.N.; Ketterson, J.B.; Hinds, B.; Marks, T.J.; Eckstein, J.

    1996-05-01

    We have used pulsed organometallic beam epitaxy (POMBE) to simultaneously deposit {cflx {ital a}} and {cflx {ital c}}-axis oriented Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} (YBCO) thin films at arbitrary locations on LaAlO{sub 3}(100) substrates. Using photolithography and ion milling, several types of {cflx {ital a}}-{cflx {ital c}} weak links have been fabricated at the boundary between the two films. The current-voltage ({ital I}-{ital V}) characteristics show a flux flow type behavior. The resistive transitions are broad and the critical current density is low, indicating weak coupling across these boundaries. With magnetic field applied parallel to the grain boundary plane, nonhysteretic {ital I}-{ital V} curves are obtained and the critical current goes to zero at an applied magnetic field of {approximately}7500 Gauss. {copyright} {ital 1996 Materials Research Society.}

  3. Hydrothermal growth and characterization of vertically well-aligned and dense ZnO nanorods on glass and silicon using a simple optimizer system

    NASA Astrophysics Data System (ADS)

    Mohammad, Sabah M.; Hassan, Z.; Ahmed, Naser M.; Talib, Rawnaq A.; Abd-Alghafour, Nabeel M.; Omar, A. F.

    2016-07-01

    Vertically, well-aligned and high density ZnO nanorods were successfully hydrothermally grown on glass and silicon substrates using a simple and low cost system. The mechanism of synthesis of ZnO nanorods, generated with our system under hydrothermal conditions, is investigated in this report. Field-emission scanning electron microscopy indicated that the fabricated ZnO nanorods on both substrates have hexagonal shape with diameters ranging from 20 nm to 70 nm which grew vertically from the substrate. XRD analysis confirms the formation of wurtzite ZnO phase with a preferred orientation along (002) direction perpendicular on the substrate and enhanced crystallinity. The low value of the tensile strain (0.126 %) revealed that ZnO nanorods preferred to grow along the c-axis for both substrates. Photoluminescence spectra exhibited a strong, sharp UV near band edge emission peak with narrow FWHM values for both samples.

  4. Alignment method for parabolic trough solar concentrators

    DOEpatents

    Diver, Richard B.

    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.

  5. Structural, Magnetic and Electronic Properties of (110)-OrientedEpitaxial Thin Films of Bilayer Manganite La1.2Sr1.8Mn2O7

    SciTech Connect

    Takamura, Yayoi; Grepstad, Jostein K.; Chopdekar, Rajesh V.; Suzuki, Yuri; Marshall, Ann F.; Zheng, Hong; Mitchell, John F.

    2005-05-09

    We have synthesized (110)-oriented epitaxial thin films of the bilayer (n=2) manganite, La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7}, with the metallic/ferromagnetic a-b planes lying perpendicular to the substrate surface and the c-axis aligned in the plane of the film. X-ray diffraction and transmission electron microscopy confirm the alignment of the a-b planes along the [1{bar 1}0] substrate direction. The films consist primarily of the n=2 phase with a minor component of the n=1 (La,Sr){sub 2}MnO{sub 4} and n={infinity} (La,Sr)MnO{sub 3} phases. A resistivity maximum coincides with a ferromagnet/paramagnet transition at a reduced T{sub c}{approx}90K (vs. 120K for bulk), indicative of the effects of epitaxial strain. The films display similar anisotropic properties to their bulk counterpart with the magnetically easy direction confined to the a-b planes and 20-200 times lower resistivity for current flowing along the a-b planes compared to the c-axis.

  6. Segment alignment control system

    NASA Technical Reports Server (NTRS)

    Aubrun, JEAN-N.; Lorell, Ken R.

    1988-01-01

    The segmented primary mirror for the LDR will require a special segment alignment control system to precisely control the orientation of each of the segments so that the resulting composite reflector behaves like a monolith. The W.M. Keck Ten Meter Telescope will utilize a primary mirror made up of 36 actively controlled segments. Thus the primary mirror and its segment alignment control system are directly analogous to the LDR. The problems of controlling the segments in the face of disturbances and control/structures interaction, as analyzed for the TMT, are virtually identical to those for the LDR. The two systems are briefly compared.

  7. Degradation of the acousto-electric current saturation behavior in c-axis fiber-textured polycrystalline zinc oxide films

    SciTech Connect

    Pompe, T.; Srikant, V.; Clarke, D.R.

    1996-12-31

    Acoustic-electric current saturation has been observed in thin, polycrystalline Al-doped zinc oxide films grown on fused quartz. The films, grown by laser ablation, are c-axis textured with high angle grain boundaries between the grains. After annealing at 600 C in 0.1 mtorr oxygen, the films exhibit a current saturation at a current density of 2 10{sup 5} A/cm{sup 2} and electric fields of 5 10{sup 3} V/cm. However, under constant field the current density falls and the current saturation behavior is not maintained. Current saturation at the same current density can, however, be restored by increasing the electric field. Similarly, the appearance and disappearance of the current saturation behavior can be reversibly controlled by annealing in different oxygen partial pressures at 200 C. The degradation phenomena is attributed to the high acoustic flux enhancing the diffusion of oxygen along the grain boundaries where oxygen can alter the grain boundary potential barrier and hence the electric field in the grains.

  8. Josephson Coupling along the c-Axis in Highly Anisotropic High Temperature Superconductors at High-Magnetic-Fields

    NASA Astrophysics Data System (ADS)

    Gray, K. E.; Hettinger+, J. D.; Washburn, B.; Veal, B. W.; Paulikas, A. P.; Kostic, P.

    1996-03-01

    We have extended previous measurements of oxygen deficient YBa_2Cu_3O_y^1 to magnetic fields as high as 27T and temperatures down to 4K. Measurements were made on three samples with different oxygen contents with critical temperatures ranging from 25K to 70K. The results are consistent with those previously reported and extend those measurements over a broader range in parameter space. These measurements demonstrate an unusual temperature dependent electron transmission suggesting increased c-axis coherency below T_c. The temperature dependence of the electron transmission extends to the lowest temperatures measured. ^+Present address: Rowan College of New Jersey. High-magnetic field measurements performed with the assistance of S. T. Hannahs at the NHMFL funded by the NSF. We acknowledge the support of the D.O.E., Divisions of Basic Energy Sciences-Materials Sciences under contract W-31-109-ENG-38, and the NSF-Office of Science and Technology Centers under contract DMR 91-20000. ^1J. D. Hettinger, K. E. Gray, B.W. Veal, A. P. Paulikas, P. Kostic, B. R. Washburn, W. C. Tonjes, and A. C. Flewelling, Phys. Rev. Lett. 74, 4726 (1995).

  9. Atom probe tomography evaporation behavior of C-axis GaN nanowires: Crystallographic, stoichiometric, and detection efficiency aspects

    SciTech Connect

    Diercks, David R. Gorman, Brian P.; Kirchhofer, Rita; Sanford, Norman; Bertness, Kris; Brubaker, Matt

    2013-11-14

    The field evaporation behavior of c-axis GaN nanowires was explored in two different laser-pulsed atom probe tomography (APT) instruments. Transmission electron microscopy imaging before and after atom probe tomography analysis was used to assist in reconstructing the data and assess the observed evaporation behavior. It was found that the ionic species exhibited preferential locations for evaporation related to the underlying crystal structure of the GaN and that the species which evaporated from these locations was dependent on the pulsed laser energy. Additionally, the overall stoichiometry measured by APT was significantly correlated with the energy of the laser pulses. At the lowest laser energies, the apparent composition was nitrogen-rich, while higher laser energies resulted in measurements of predominantly gallium compositions. The percent of ions detected (detection efficiency) for these specimens was found to be considerably below that shown for other materials, even for laser energies which produced the expected Ga:N ratio. The apparent stoichiometry variation and low detection efficiency appear to be a result of evaporation of Ga ions between laser pulses at the lowest laser energies and evaporation of neutral N{sub 2} species at higher laser energies. All of these behaviors are tied to the formation of nitrogen-nitrogen bonds on the tip surface, which occurred under all analysis conditions. Similar field evaporation behaviors are therefore expected for other materials where the anionic species readily form a strong diatomic bond.

  10. Are quartz LPOs predictably oriented with respect to the shear zone boundary?: A test from the Alpine Fault mylonites, New Zealand

    NASA Astrophysics Data System (ADS)

    Little, Timothy A.; Prior, David J.; Toy, Virginia G.

    2016-03-01

    The Alpine fault self-exhumes its own ductile shear zone roots and has a known slip kinematics. Within ˜1 km of the fault, the mylonitic foliation is subparallel to the boundary of the amphibolite-facies ductile shear zone in which it formed. Using EBSD, we analyzed quartz Lattice Preferred Orientations [LPOs) of mylonites along a central part of the Alpine Fault. All LPOs feature a strongest girdle of [c]-axes that is forward-inclined ˜28 ± 4° away from the pole to the fault. A maximum of axes is inclined at the same angle relative the fault. The [c]-axis girdle is perpendicular to extensional (C') shear bands and the maximum is parallel to their slip direction. [c]-axis girdles do not form perpendicular to the SZB. Schmid factor analysis suggests that σ1 was arranged at 60-80° to the Alpine Fault. These observations indicate ductile transpression in the shear zone. The inclined arrangement of [c]-axis girdles, axes, and C' planes relative to the fault can be explained by their alignment relative to planes of maximum shear-strain-rate in a general shear zone, a significant new insight regarding shear zones and how LPO fabrics may generally develop within them. For the Alpine mylonite zone, our data imply a kinematic vorticity number (Wk) of ˜0.7 to ˜0.85. Inversions of seismic focal mechanisms in the brittle crust of the Southern Alps indicate that σ1 is oriented ˜60° to the Alpine Fault; that shear bands form at ˜30° to this direction, and that σ2 and σ3 flip positions between the brittle and ductile parts of the crust.

  11. Nuclear reactor internals alignment configuration

    DOEpatents

    Gilmore, Charles B.; Singleton, Norman R.

    2009-11-10

    An alignment system that employs jacking block assemblies and alignment posts around the periphery of the top plate of a nuclear reactor lower internals core shroud to align an upper core plate with the lower internals and the core shroud with the core barrel. The distal ends of the alignment posts are chamfered and are closely received within notches machined in the upper core plate at spaced locations around the outer circumference of the upper core plate. The jacking block assemblies are used to center the core shroud in the core barrel and the alignment posts assure the proper orientation of the upper core plate. The alignment posts may alternately be formed in the upper core plate and the notches may be formed in top plate.

  12. Pyroelectric-field driven defects diffusion along c-axis in ZnO nanobelts under high-energy electron beam irradiation

    SciTech Connect

    Ding, Yong Liu, Ying; Niu, Simiao; Wu, Wenzhuo; Wang, Zhong Lin

    2014-10-21

    When ZnO nanobelts are exposed to a high-dose electron probe of several nanometers to hundred nanometers in diameter inside a transmission electron microscope, due to the radiolysis effect, part of oxygen atoms will be ejected into the vacuum and leaving a Zn-ion rich surface with a pit appearance at both the electron-entrance and electron-exit surfaces. At the same time, a temperature distribution is created around the electron probe due to local beam heating effect, which generates a unidirectional pyroelectric field. This pyroelectric field is strong enough to drive Zn ions moving along its positive c-axis direction as interstitial ions. In the first case, for the ZnO nanobelts with c-axis lie in their large surfaces, defects due to the aggregation of Zn interstitial ions will be formed at some distances of 30–50 nm approximately along the c-axis direction from the electron beam illuminated area. Alternatively, for the ZnO nanobelts with ±(0001) planes as their large surfaces, the incident electron beam is along its c-axis and the generated pyroelectric field will drive the interstitial Zn-ions to aggregate at the Zn terminated (0001) surface where the local electrical potential is the lowest. Such electron beam induced damage in ZnO nanostructures is suggested as a result of Zn ion diffusion driven by the temperature gradient induced pyroelectric field along c-axis. Our study shows a radiation damage caused by electron beam in transmission electron microscopy, especially when the electron energy is high.

  13. The alignment of a voltage-sensing peptide in dodecylphosphocholine micelles and in oriented lipid bilayers by nuclear magnetic resonance and molecular modeling.

    PubMed Central

    Mattila, K; Kinder, R; Bechinger, B

    1999-01-01

    The S4 segments of voltage-gated sodium channels are important parts of the voltage-sensing elements of these proteins. Furthermore, the addition of the isolated S4 polypeptide to planar lipid bilayers results in stepwise increases of ion conductivity. In order to gain insight into the mechanisms of pore formation by amphipathic peptides, the structure and orientation of the S4 segment of the first internal repeat of the rat brain II sodium channel was investigated in the presence of DPC micelles by multidimensional solution NMR spectroscopy and solid-state NMR spectroscopy on oriented phospholipid bilayers. Both the anisotropic chemical shift observed by proton-decoupled (15)N solid-state NMR spectroscopy and the attenuating effects of DOXYL-stearates on TOCSY crosspeak intensities of micelle-associated S4 indicate that the central alpha-helical portion of this peptide is oriented approximately parallel to the membrane surface. Simulated annealing and molecular dynamics calculations of the peptide in a biphasic tetrachloromethane-water environment indicate that the peptide alpha-helix extends over approximately 12 residues. A less regular structure further toward the C-terminus allows for the hydrophobic residues of this part of the peptide to be positioned in the tetrachloromethane environment. The implications for possible pore-forming mechanisms are discussed. PMID:10512830

  14. Alignment validation

    SciTech Connect

    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.

  15. Growth of (Y1-x Ca x )Ba2Cu4O8 in ambient pressure and its tri-axial magnetic alignment

    NASA Astrophysics Data System (ADS)

    Horii, S.; Yamaki, M.; Shimoyama, J.; Kishio, K.; Doi, T.

    2015-10-01

    We report the growth of single crystals in ambient pressure and tri-axial orientation under modulated rotation magnetic fields (MRFs) for (Y1-x Ca x )Ba2Cu4O8 [(Y1-x Ca x )124] with x ≤ 0.1. Rectangular (Y1-x Ca x )124 crystals approximately 50 μm in size have been successfully grown for x ≤ 0.1 in a growth temperature region from 650 °C to 750 °C. Their critical temperatures increased with x and exhibited approximately 91 K for x = 0.1. By applying an MRF of 10 T, pulverised powders of (Y1-x Ca x )124 were tri-axially aligned in epoxy resin at room temperature in a whole x region below x = 0.1. The magnitude relationship of the magnetic susceptibilities (χ) along crystallographic directions for (Y1-x Ca x )124 was χ c > χ a > χ b at room temperature and was unchanged with a change in x. From changes in the degrees of the c-axis and the in-plane orientation (Δω) for the (Y1-x Ca x )124 powder samples aligned under three different MRF conditions, it was found that MRFs above at least 1 T were required to achieve almost complete tri-axial alignment with Δω < 5°. Irreversibility lines for H//c were successfully determined even from the powder samples by the introduction of magnetic alignment without using single crystalline samples. The present study indicates that magnetic alignment is a useful process for the fabrication of quasi-single-crystals from the perspective of solid-state physics and the production of cuprate superconducting materials.

  16. Investigation of easy axis orientation of Nd-Fe-B melt-spun ribbons produced by hot rolling and influence of Ti-C addition

    SciTech Connect

    Takezawa, M.; Nakanishi, Y.; Morimoto, Y.; Yamasaki, J.; Yagi, M.

    2012-04-01

    The c-axis orientation of Nd-Fe-B melt-spun ribbons caused by hot rolling and the influence of Ti-C addition were investigated. A small roll was placed on a steel wheel near a quartz tube in such a manner that the melt-spun ribbons were hot rolled immediately after quenching. X-ray diffraction patterns measured on both surfaces of the Nd-Fe-B-Ti ribbon indicate that the c-axis is oriented normal to the ribbon plane. The domain pattern of the Nd-Fe-B-Ti-C ribbon was observed with a Kerr microscope. Most of the grains exhibit a maze domain configuration, indicating that the c-axis is oriented normal to the ribbon plane. Furthermore, it was demonstrated that hot rolling and the addition of Ti-C promote c-axis orientation and high coercivity of Nd-Fe-B melt-spun ribbons.

  17. c -axis longitudinal magnetoresistance of the electron-doped superconductor Pr1.85Ce0.15CuO4

    NASA Astrophysics Data System (ADS)

    Yu, W.; Liang, B.; Greene, R. L.

    2006-12-01

    We report c -axis resistivity and longitudinal magnetoresistance measurements of superconducting Pr1.85Ce0.15CuO4 single crystals. In the temperature range 13⩽T⩽32K , a negative magnetoresistance is observed at fields just above HC2 . Our studies suggest that this negative magnetoresistance is caused by superconducting fluctuations. At lower temperatures (T⩽13K) , a different magnetoresistance behavior and a resistivity upturn are observed, whose origin is still unknown.

  18. Collective responses of Bi-2212 stacked junction to 100 GHz microwave radiation under magnetic field oriented along the c-axis

    NASA Astrophysics Data System (ADS)

    Pavlenko, V. N.; Latyshev, Yu. I.; Chen, J.; Gaifullin, M. B.; Irzhak, A.; Kim, S.-J.; Wu, P. H.

    2009-05-01

    We studied a response of Bi-2212 mesa type structures to 100 GHz microwave radiation. We found that applying magnetic field of about 0.1 T across the layers enables to observe collective Shapiro step response corresponding to a synchronization of all 50 intrinsic Josephson junctions (IJJ) of the mesa. At high microwave power we observed up to 10th harmonics of the fundamental Shapiro step. Besides, we found microwave induced flux-flow step position of which is proportional to the square root of microwave power and that can exceed at high enough powers 1 THz operating frequency of IJJ oscillations.

  19. Transport and optical properties of c-axis oriented wedge shaped GaN nanowall network grown by molecular beam epitaxy

    SciTech Connect

    Bhasker, H. P.; Dhar, S.; Thakur, Varun; Kesaria, Manoj; Shivaprasad, S. M.

    2014-02-21

    The transport and optical properties of wedge-shaped nanowall network of GaN grown spontaneously on cplane sapphire substrate by Plasma-Assisted Molecular Beam Epitaxy (PAMBE) show interesting behavior. The electron mobility at room temperature in these samples is found to be orders of magnitude higher than that of a continuous film. Our study reveals a strong correlation between the mobility and the band gap in these nanowall network samples. However, it is seen that when the thickness of the tips of the walls increases to an extent such that more than 70% of the film area is covered, it behaves close to a flat sample. In the sample with lower surface coverage (≈40% and ≈60%), it was observed that the conductivity, mobility as well as the band gap increase with the decrease in the average tip width of the walls. Photoluminescence (PL) experiments show a strong and broad band edge emission with a large (as high as ≈ 90 meV) blue shift, compared to that of a continuous film, suggesting a confinement of carriers on the top edges of the nanowalls. The PL peak width remains wide at all temperatures suggesting the existence of a high density of tail states at the band edge, which is further supported by the photoconductivity result. The high conductivity and mobility observed in these samples is believed to be due to a “dissipation less” transport of carriers, which are localized at the top edges (edge states) of the nanowalls.

  20. Development of quartz c-axis crossed/single girdles under simple-pure shear deformation: Results of visco-plastic self-consistent modeling

    NASA Astrophysics Data System (ADS)

    Nie, Guanjun; Shan, Yehua

    2014-09-01

    Quartz c-axis fabrics are widely used to determine the shear plane in ductile shear zones, based upon an assumption that the shear plane is perpendicular to both the central segment of quartz c-axis crossed girdle and single girdle. In this paper the development of quartz c-axis fabric under simple-pure shear deformation is simulated using the visco-plastic self-consistent (VPSC) model so as to re-examine this assumption. In the case of no or weak dynamic recrystallization, the simulated crossed girdles have a central segment perpendicular or nearly perpendicular to the maximum principal finite strain direction (X) and the XY finite strain plane, and at a variable angle relative to the imposed kinematic framework that is dependent on the modeled flow vorticity and finite strain. These crossed girdles have a symmetrical skeleton with respect to the finite strain axes, regardless of the bulk strain and the kinematic vorticity, and rotate in a way similar to the shear sense with increasing bulk strain ratio. The larger the vorticity number the more asymmetrical their legs tend to be. In the case of strong dynamic recrystallization and large bulk strain, under simple shear the crossed girdle switches into single girdles, sub-perpendicular to the shear plane, by losing the weak legs. The numerical results in our models do not confirm the above-mentioned assumption.

  1. Charge-screening role of c-axis atomic displacements in YBa2Cu3O6+x and related superconductors

    DOE PAGES

    E. S. Bozin; Huq, A.; Shen, Bing; Claus, H.; Kwok, W. K.; Tranquada, J. M.

    2016-02-29

    Here, the importance of charge reservoir layers for supplying holes to the CuO2 planes of cuprate superconductors has long been recognized. Less attention has been paid to the screening of the charge transfer by the intervening ionic layers. We address this issue in the case of YBa2Cu3O6+x, where CuO chains supply the holes for the planes. We present a simple dielectric-screening model that gives a linear correlation between the relative displacements of ions along the c axis, determined by neutron powder diffraction, and the hole density of the planes. Applying this model to the temperature-dependent shifts of ions along themore » c axis, we infer a charge transfer of 5–10% of the hole density from the planes to the chains on warming from the superconducting transition to room temperature. Given the significant coupling of c-axis displacements to the average charge density, we point out the relevance of local displacements for screening charge modulations and note recent evidence for dynamic screening of in-plane quasiparticles. This line of argument leads us to a simple model for atomic displacements and charge modulation that is consistent with images from scanning-tunneling microscopy for underdoped Bi2Sr2CaCu2O8+δ.« less

  2. Dynamic control of substrate bias for highly c-axis textured thin ferromagnetic CoCrTa film in inductively coupled plasma-assisted sputtering

    SciTech Connect

    Okimura, Kunio; Oyanagi, Junya

    2005-01-01

    This study shows highly c-axis textured thin ferromagnetic Co-based alloy (CoCrTa) film growth in inductively coupled plasma (ICP)-assisted sputtering with an internal coil with an insulated surface. Dynamic control of the substrate bias achieved highly c-axis textured CoCrTa film with a thickness of 70 nm in 3 min depositions on a Si substrate. The prepared film showed a smooth, dense surface consisting of small crystal grains. The film had a perpendicular magnetic coercivity of 1030 Oe and coercive squareness of 0.36. ICP-assisted sputtering with an internal coil with an insulated surface enabled higher-density ({>=}1.0x10{sup 11} cm{sup -3}) plasma with lower space potential ({<=}30 V) compared to ICP-assisted sputtering with bare coil systems. Therefore, the proposed bias control is quite effective for textured growth of thinner Co layers via the effect of a high flux of ions with proper energies. This method can be a candidate for the deposition technique of c-axis textured films as perpendicular magnetic recording media.

  3. Alignment fixture

    DOEpatents

    Bell, Grover C.; Gibson, O. Theodore

    1980-01-01

    A part alignment fixture is provided which may be used for precise variable lateral and tilt alignment relative to the fixture base of various shaped parts. The fixture may be used as a part holder for machining or inspection of parts or alignment of parts during assembly and the like. The fixture includes a precisely machined diameter disc-shaped hub adapted to receive the part to be aligned. The hub is nested in a guide plate which is adapted to carry two oppositely disposed pairs of positioning wedges so that the wedges may be reciprocatively positioned by means of respective micrometer screws. The sloping faces of the wedges contact the hub at respective quadrants of the hub periphery. The lateral position of the hub relative to the guide plate is adjusted by positioning the wedges with the associated micrometer screws. The tilt of the part is adjusted relative to a base plate, to which the guide plate is pivotally connected by means of a holding plate. Two pairs of oppositely disposed wedges are mounted for reciprocative lateral positioning by means of separate micrometer screws between flanges of the guide plate and the base plate. Once the wedges are positioned to achieve the proper tilt of the part or hub on which the part is mounted relative to the base plate, the fixture may be bolted to a machining, inspection, or assembly device.

  4. Curriculum Alignment.

    ERIC Educational Resources Information Center

    Crowell, Ronald; Tissot, Paula

    Curriculum alignment (CA) refers to the congruence of all the elements of a school's curriculum: curriculum goals; instructional program--what is taught and the materials used; and tests used to judge outcomes. CA can be a very powerful can be a very powerful factor in improving schools. Although further research is needed on CA, there is…

  5. Phosphorylation and the N-terminal extension of the regulatory light chain help orient and align the myosin heads in Drosophila flight muscle

    SciTech Connect

    Farman, Gerrie P.; Miller, Mark S.; Reedy, Mary C.; Soto-Adames, Felipe N.; Vigoreaux, Jim O.; Maughan, David W.; Irving, Thomas C.

    2010-02-02

    X-ray diffraction of the indirect flight muscle (IFM) in living Drosophila at rest and electron microscopy of intact and glycerinated IFM was used to compare the effects of mutations in the regulatory light chain (RLC) on sarcomeric structure. Truncation of the RLC N-terminal extension (Dmlc2{sup {Delta}2-46}) or disruption of the phosphorylation sites by substituting alanines (Dmlc2{sup S66A, S67A}) decreased the equatorial intensity ratio (I{sub 20}/I{sub 10}), indicating decreased myosin mass associated with the thin filaments. Phosphorylation site disruption (Dmlc2{sup S66A, S67A}), but not N-terminal extension truncation (Dmlc2{sup {Delta}2-46}), decreased the 14.5 nm reflection intensity, indicating a spread of the axial distribution of the myosin heads. The arrangement of thick filaments and myosin heads in electron micrographs of the phosphorylation mutant (Dmlc2{sup S66A, S67A}) appeared normal in the relaxed and rigor states, but when calcium activated, fewer myosin heads formed cross-bridges. In transgenic flies with both alterations to the RLC (Dmlc2{sup {Delta}2-46; S66A, S67A}), the effects of the dual mutation were additive. The results suggest that the RLC N-terminal extension serves as a 'tether' to help pre-position the myosin heads for attachment to actin, while phosphorylation of the RLC promotes head orientations that allow optimal interactions with the thin filament.

  6. ALIGNING JIG

    DOEpatents

    Culver, J.S.; Tunnell, W.C.

    1958-08-01

    A jig or device is described for setting or aligning an opening in one member relative to another member or structure, with a predetermined offset, or it may be used for measuring the amount of offset with which the parts have previously been sct. This jig comprises two blocks rabbeted to each other, with means for securing thc upper block to the lower block. The upper block has fingers for contacting one of the members to be a1igmed, the lower block is designed to ride in grooves within the reference member, and calibration marks are provided to determine the amount of offset. This jig is specially designed to align the collimating slits of a mass spectrometer.

  7. Aligned AlN nanowires by self-organized vapor-solid growth

    NASA Astrophysics Data System (ADS)

    Yazdi, G. R.; Persson, P. O. Å.; Gogova, D.; Fornari, R.; Hultman, L.; Syväjärvi, M.; Yakimova, R.

    2009-12-01

    Highly oriented AlN single crystal nanowires with aspect ratio up to 600, diameter in the range of 40-500 nm, and 100 µm lengths, have been synthesized via a vapor-solid growth mechanism. The results were obtained at 1750 °C and 850 mbar nitrogen pressure on vicinal SiC substrates pretreated by SiC sublimation epitaxy in order to attain distinguishable terraces. It was found that the nanowires change in thickness after they have reached a critical length, and this fact contributes to an understanding of the growth mechanism of AlN nanowires. The nanowires are hexagonally shaped and perfectly aligned along the [0001] direction with a small tilt given by the substrate vicinality. Under nitrogen excess a preferential growth along the c-axis of the wurtzite structure takes place while below some critical value of nitrogen pressure the growth mode switches to lateral. The AlN nanowires are shown to have a dislocation free wurtzite crystal structure. Some possible applications are discussed.

  8. Aligned AlN nanowires by self-organized vapor-solid growth.

    PubMed

    Yazdi, G R; Persson, P O A; Gogova, D; Fornari, R; Hultman, L; Syväjärvi, M; Yakimova, R

    2009-12-01

    Highly oriented AlN single crystal nanowires with aspect ratio up to 600, diameter in the range of 40-500 nm, and 100 microm lengths, have been synthesized via a vapor-solid growth mechanism. The results were obtained at 1750 degrees C and 850 mbar nitrogen pressure on vicinal SiC substrates pretreated by SiC sublimation epitaxy in order to attain distinguishable terraces. It was found that the nanowires change in thickness after they have reached a critical length, and this fact contributes to an understanding of the growth mechanism of AlN nanowires. The nanowires are hexagonally shaped and perfectly aligned along the [0001] direction with a small tilt given by the substrate vicinality. Under nitrogen excess a preferential growth along the c-axis of the wurtzite structure takes place while below some critical value of nitrogen pressure the growth mode switches to lateral. The AlN nanowires are shown to have a dislocation free wurtzite crystal structure. Some possible applications are discussed.

  9. Image alignment

    SciTech Connect

    Dowell, Larry Jonathan

    2014-04-22

    Disclosed is a method and device for aligning at least two digital images. An embodiment may use frequency-domain transforms of small tiles created from each image to identify substantially similar, "distinguishing" features within each of the images, and then align the images together based on the location of the distinguishing features. To accomplish this, an embodiment may create equal sized tile sub-images for each image. A "key" for each tile may be created by performing a frequency-domain transform calculation on each tile. A information-distance difference between each possible pair of tiles on each image may be calculated to identify distinguishing features. From analysis of the information-distance differences of the pairs of tiles, a subset of tiles with high discrimination metrics in relation to other tiles may be located for each image. The subset of distinguishing tiles for each image may then be compared to locate tiles with substantially similar keys and/or information-distance metrics to other tiles of other images. Once similar tiles are located for each image, the images may be aligned in relation to the identified similar tiles.

  10. Galaxy Alignments: Theory, Modelling & Simulations

    NASA Astrophysics Data System (ADS)

    Kiessling, Alina; Cacciato, Marcello; Joachimi, Benjamin; Kirk, Donnacha; Kitching, Thomas D.; Leonard, Adrienne; Mandelbaum, Rachel; Schäfer, Björn Malte; Sifón, Cristóbal; Brown, Michael L.; Rassat, Anais

    2015-11-01

    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 the large-scale structure tend to align nearby galaxies. Additionally, events such as galaxy mergers affect the relative alignments of both the shapes and angular momenta 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 field, providing a solid basis for future work.

  11. Crystal orientations in nacreous layers of organic-inorganic biocomposites

    SciTech Connect

    Lee, Seung Woo

    2009-09-15

    Abalone shell comprises a bio-composite material, combining the properties of inorganic calcite intergrown with organic nacre. This paper reports about the microstructure of this composite. By examining the Kikuchi patterns obtained for nacre (Haliotis discus hannai) using transmission electron microscopy, we have shown that the tiles within nacre have specific orientations. The stereographic projection spheres for the tiles of nacre can be divided into two main types, namely a right oriented region and a left oriented region with respect to the c axis as a reference plane (001). The cluster character of nacre can be explained in terms of the growth mechanism of the 'Christmas tree' pattern. The orientation of the c-axis in the nacreous layer is elucidated for the first time. We demonstrate the use of the soluble protein obtained from the tiles of nacre in in vitro calcium carbonate crystallization.

  12. Investigations on the growth and characterization of vertically aligned zinc oxide nanowires by radio frequency magnetronsputtering

    SciTech Connect

    Venkatesh, P. Sundara; Jeganathan, K.

    2013-04-15

    Undoped vertically aligned ZnO nanowires have been grown on silicon (111) substrates by the rf magnetron sputtering technique without metal catalyst. The diameter, length and density distributions of the nanowires have been analyzed with respect to the different growth durations. The tapering of the nanowires is observed for the growth duration of 120 min owing to the insufficient adatoms on the growth front. In the X-ray diffraction pattern, the dominant (002) peak with narrow full width at half maximum (FWHM) of ZnO nanowires indicates the c-axis orientation and high crystalline nature with hexagonal wurtzite crystal structure. The narrow FWHM of E{sub 2}{sup low} and E{sub 2}{sup high} phonon modes (1.4 and 9.1 cm{sup −1}) provide an additional evidence for the high crystalline and optical properties of the nanowires. The low temperature photoluminescence spectra are dominated by the green emission at∼2.28 eV induced by the electron transitions between shallow donor and acceptor energy levels. - Graphical abstract: Coalescence free vertically aligned ZnO nanowires have been grown on silicon (111) substrate by the radio frequency magnetron sputtering technique. Highlights: ► ZnO nanowires have been grown by rf magnetron sputtering. ► A morphologically superior and coalescence free ZnO nanowires have been realized. ► ZnO nanowires exhibit hexagonal wurtzite crystal structure. ► A dominant visible emission indicates the presence of point defects in nanowires.

  13. Photoinduced enhancement of the c-axis conductivity in oxygen-deficient YBa{sub 2}Cu{sub 3}O{sub x} thin films

    SciTech Connect

    Markowitsch, W.; Stockinger, C.; Lang, W. |; Bierleutgeb, K.; Pedarnig, J.D.; Baeuerle, D.

    1997-09-01

    High quality thin films of oxygen-depleted YBa{sub 2}Cu{sub 3}O{sub x} (x{approx}6.6) were prepared by pulsed-laser deposition on SrTiO{sub 3}, substrates that were cut with tilt angles of 10{degree} and 20{degree} with respect to the [001] direction, resulting in a steplike growth of the layers. The resistance showed a semiconducting behavior along the projection of the c axis to the film surface, but a metallic behavior in the perpendicular direction, indicating that the former is dominated by the c-axis resistivity and the latter by the ab-plane resistivity of YBa{sub 2}Cu{sub 3}O{sub x}. Long-term illumination of the samples with a 100 W halogen lamp resulted in a significant conductivity enhancement in both directions. The photoinduced change of the out-of-plane resistance vs temperature characteristics is comparable to the effect of large hydrostatic pressure, introducing structural changes similar to that of photoexcitation. {copyright} {ital 1997 American Institute of Physics.}

  14. Preparation of bi-axially aligned YBa 2Cu 3O 7- δ film on CeO 2-buffered MgO by chemical solution deposition

    NASA Astrophysics Data System (ADS)

    Yamagiwa, K.; Hiei, H.; Takahashi, Y.; Kim, S. B.; Matsumoto, K.; Ikuta, H.; Mizutani, U.; Hirabayashi, I.

    2000-06-01

    We have succeeded in preparing in-plane aligned YBa 2Cu 3O 7- δ (Y123) film by chemical solution deposition (CSD) processing on CeO 2 (100)-buffered MgO (100) substrates. The CeO 2 buffer film was deposited on MgO (100) single crystalline substrate by pulsed laser deposition (PLD). For CSD coating, a homogeneous coating solution having a molar ratio of Y:Ba:Cu=1:2:3, was prepared by dissolving metal naphthenates in toluene. This solution was spin-coated both on the YSZ (100) and on the CeO 2-buffered MgO (100) single crystalline substrates. The precursor films were calcined at 425°C and fired at various temperatures under low oxygen partial pressure ( pO 2). All Y123 films showed strong (00 n) peaks, which correspond to c-axis orientation perpendicular to the substrates and their a/ b-axes were in-plane aligned. We confirmed that CeO 2 buffer is usable for CSD processing. While the Y123 films on the YSZ reacted with the substrate forming BaZrO 3 phase and did not show sufficient superconducting properties. The Tc,zero value of the Y123 film prepared on CeO 2-buffered MgO substrate was 91.5 K and Jc was 1.2×10 5 A/cm 2 at 77 K, 0 T.

  15. Global alignment: Finding rearrangements during alignment

    SciTech Connect

    Brudno, Michael; Malde, Sanket; Poliakov, Alexander; Do, Chuong B.; Couronne, Olivier; Dubchak, Inna; Batzoglou, Serafim

    2003-01-06

    Motivation: To compare entire genomes from different species, biologists increasingly need alignment methods that are efficient enough to handle long sequences, and accurate enough to correctly align the conserved biological features between distant species. The two main classes of pairwise alignments are global alignment, where one string is transformed into the other, and local alignment, where all locations of similarity between the two strings are returned. Global alignments are less prone to demonstrating false homology as each letter of one sequence is constrained to being aligned to only one letter of the other. Local alignments, on the other hand, can cope with rearrangements between non-syntenic, orthologous sequences by identifying similar regions in sequences; this, however, comes at the expense of a higher false positive rate due to the inability of local aligners to take into account overall conservation maps.

  16. Microstructural characterization of an oriented silicalite film

    SciTech Connect

    Lovallo, M.C.; Tsapatsis, M.

    1997-12-31

    The crystal orientation of a submicron silicalite membrane is examined using standard x-ray diffraction and pole-figure analyses. Results indicate that the crystals in the molecular sieving layer are preferentially oriented with both straight and sinusoidal channel networks of the zeolite parallel to the membrane surface. This requires that transport across the membrane proceed down the c-axis of the crystals which can occur by jumping between the two channel networks. EDAX data confirms that the molecular sieving layer is the pure silica zeolite silicalite.

  17. c -Axis Electronic Raman Scattering in Bi{sub 2} Sr{sub 2} CaCu{sub 2} O{sub 8+{delta} }

    SciTech Connect

    Liu, H.L.; Blumberg, G.; Klein, M.V.; Guptasarma, P.; Hinks, D.G.; Blumberg, G.

    1999-04-01

    We report on the c -axis-polarized electronic Raman scattering of Bi{sub 2}Sr {sub 2}CaCu{sub 2}O{sub 8+{delta}} single crystals with various oxygen concentrations. In the normal state, a resonant electronic continuum extends to 1.5thinspthinspeV and gains significant intensity as the incoming photon energy increases. Below T{sub c} , a superconductivity-induced 2{Delta} peak is observed for {omega}{lt}80 meV and the 2{Delta}/k{sub B}T{sub c} value increases with decreasing hole doping. In particular, this A{sub 1g} 2{Delta} peak energy, which is higher than that seen with in-plane polarizations for all doping levels studied, signifies distinctly different dynamics of quasiparticles created with out-of-plane polarization. {copyright} {ital 1999} {ital The American Physical Society}

  18. Influence of the spatially inhomogeneous gap distribution on the quasiparticle current in c-axis junctions involving d-wave superconductors with charge density waves.

    PubMed

    Ekino, T; Gabovich, A M; Suan Li, Mai; Szymczak, H; Voitenko, A I

    2016-11-01

    The quasiparticle tunnel current J(V) between the superconducting ab-planes along the c-axis and the corresponding conductance [Formula: see text] were calculated for symmetric junctions composed of disordered d-wave layered superconductors partially gapped by charge density waves (CDWs). Here, V is the voltage. Both the checkerboard and unidirectional CDWs were considered. It was shown that the spatial spread of the CDW-pairing strength substantially smears the peculiarities of G(V) appropriate to uniform superconductors. The resulting curves G(V) become very similar to those observed for a number of cuprates in intrinsic junctions, e.g. mesas. In particular, the influence of CDWs may explain the peak-dip-hump structures frequently found for high-T c oxides. PMID:27604150

  19. Influence of the spatially inhomogeneous gap distribution on the quasiparticle current in c-axis junctions involving d-wave superconductors with charge density waves

    NASA Astrophysics Data System (ADS)

    Ekino, T.; Gabovich, A. M.; Li, Mai Suan; Szymczak, H.; Voitenko, A. I.

    2016-11-01

    The quasiparticle tunnel current J(V) between the superconducting ab-planes along the c-axis and the corresponding conductance G(V)=\\text{d}J/\\text{d}V were calculated for symmetric junctions composed of disordered d-wave layered superconductors partially gapped by charge density waves (CDWs). Here, V is the voltage. Both the checkerboard and unidirectional CDWs were considered. It was shown that the spatial spread of the CDW-pairing strength substantially smears the peculiarities of G(V) appropriate to uniform superconductors. The resulting curves G(V) become very similar to those observed for a number of cuprates in intrinsic junctions, e.g. mesas. In particular, the influence of CDWs may explain the peak-dip-hump structures frequently found for high-T c oxides.

  20. c-axis inclined ZnO films for shear-wave transducers deposited by reactive sputtering using an additional blind

    SciTech Connect

    Link, M.; Schreiter, M.; Weber, J.; Gabl, R.; Pitzer, D.; Primig, R.; Wersing, W.; Assouar, M.B.; Elmazria, O.

    2006-03-15

    This article reports on the growth and characterization of polycrystalline ZnO films having c axis inclined up to 16 deg. with respect to the substrate normal. These films allow the excitation of shear and longitudinal waves with comparable electromechanical coupling constants and are of significant interest for thin film bulk acoustic resonators (FBARs). The films are deposited on silicon substrates covered by Al{sub 2}O{sub 3} and SiO{sub 2} buffer layers under low pressure using a modified reactive dc-pulsed magnetron sputtering system. A blind has been positioned between target and substrate, allowing oblique particle incidence without tilting the wafer. The study of structural properties of the deposited ZnO films by x-ray diffraction and scanning electron microscopy has permitted to show the presence of the inclined structure. Electromechanical coupling constants K up to 13% have been extracted for shear-mode excitation using highly overmoded FBARs.

  1. Effect of gamma irradiation on Schottky-contacted vertically aligned ZnO nanorod-based hydrogen sensor

    NASA Astrophysics Data System (ADS)

    Ranwa, Sapana; Singh Barala, Surendra; Fanetti, Mattia; Kumar, Mahesh

    2016-08-01

    We report the impact of gamma irradiation on the performance of a gold Schottky-contacted ZnO nanorod-based hydrogen sensor. RF-sputtered vertically aligned highly c-axis-oriented ZnO NRs were grown on Si(100) substrate. X-ray diffraction shows no significant change in crystal structure at low gamma doses from 1 to 5 kGy. As gamma irradiation doses increase to 10 kGy, the single crystalline ZnO structure converts to polycrystalline. The photoluminescence spectra also shows suppression of the near-band emission peak and the huge wide-band spectrum indicates the generation of structural defects at high gamma doses. At 1 kGy, the hydrogen sensor response was enhanced from 67% to 77% for 1% hydrogen in pure argon at a 150 °C operating temperature. However, at 10 kGy, the relative response decreases to 33.5%. High gamma irradiation causes displacement damage and defects in ZnO NRs, and as a result, degrades the sensor’s performance as a result. Low gamma irradiation doses activate the ZnO NR surface through ionization, which enhances the sensor performance. The relative response of the hydrogen sensor was enhanced by ∼14.9% with respect to pristine ZnO using 1 kGy gamma ray treatment.

  2. Effect of gamma irradiation on Schottky-contacted vertically aligned ZnO nanorod-based hydrogen sensor.

    PubMed

    Ranwa, Sapana; Barala, Surendra Singh; Fanetti, Mattia; Kumar, Mahesh

    2016-08-26

    We report the impact of gamma irradiation on the performance of a gold Schottky-contacted ZnO nanorod-based hydrogen sensor. RF-sputtered vertically aligned highly c-axis-oriented ZnO NRs were grown on Si(100) substrate. X-ray diffraction shows no significant change in crystal structure at low gamma doses from 1 to 5 kGy. As gamma irradiation doses increase to 10 kGy, the single crystalline ZnO structure converts to polycrystalline. The photoluminescence spectra also shows suppression of the near-band emission peak and the huge wide-band spectrum indicates the generation of structural defects at high gamma doses. At 1 kGy, the hydrogen sensor response was enhanced from 67% to 77% for 1% hydrogen in pure argon at a 150 °C operating temperature. However, at 10 kGy, the relative response decreases to 33.5%. High gamma irradiation causes displacement damage and defects in ZnO NRs, and as a result, degrades the sensor's performance as a result. Low gamma irradiation doses activate the ZnO NR surface through ionization, which enhances the sensor performance. The relative response of the hydrogen sensor was enhanced by ∼14.9% with respect to pristine ZnO using 1 kGy gamma ray treatment. PMID:27418478

  3. Prism Window for Optical Alignment

    NASA Technical Reports Server (NTRS)

    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.

  4. Quartz c-axis fabrics in constrictionally strained orthogneisses: implications for the evolution of the Orlica-Śnieżnik Dome, the Sudetes, Poland

    NASA Astrophysics Data System (ADS)

    Żelaźniewicz, Andrzej; Kromuszczyńska, Olga; Biegała, Natalia

    2013-12-01

    Żelaźniewicz, A., Kromuszczyńska, O. and Biegała, N. 2013. Quartz c-axis fabrics in constrictionally strained orthogneisses: implications for the evolution of the Orlica-Śnieżnik Dome, the Sudetes, Poland. Acta Geologica Polonica, 63(4), 697-722, Warszawa. The Orlica-Śnieżnik Dome (OSD), NE Bohemian Massif, contains in its core several gneiss variants with protoliths dated at ~500 Ma. In the western limb of the OSD, rodding augen gneisses (Spalona gneiss unit) are mainly L>S tectonites with a prominent stretching lineation. The few quartz LPO studies have produced somewhat discrepant results. Reexamination of these rocks revealed that texture formation was a protracted, multistage process that involved strain partitioning with changing strain rate and kinematics in a general shear regime at temperatures of the amphibolite facies (450-600°C). Quartz c-axis microfabrics show complex yet reproducible patterns that developed under the joint control of strain geometry and temperature; thus the LPOs are mixed features represented by pseudogirdle patterns. Domainal differences in quartz microfabrics (ribbons, tails, quartzo-feldspathic aggregate) are common in the Spalona orthogneisses but uncommon in the sheared migmatitic gneisses. In the latter rocks, the constrictional strain was imposed on the originally planar fabric defined by high-temperature migmatitic layering. The constrictional fabric of the Spalona gneisses may have developed in the hinge zones of kilometer-scale folds, where the elongation occurred parallel to the fold axes. Other occurrences of rodding gneisses throughout the Orlica-Śnieżnik Dome are thought to occupy similar structural positions, which would point to the significance of large-scale folds in the tectonic structure of the dome.

  5. Effect on C-axis transport properties of a critical state in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}

    SciTech Connect

    Cho, J.H.; Maley, M.P.; Bulaevskii, L.N.

    1995-12-31

    At low temperatures, the c-axis transport properties of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} single crystals depend strongly on the magnetic field history for fields applied along the c-axis, indicating the effect of a critical state in the ab direction. In this study, the authors report zero field cooled (ZFC), field cooled warming (FCW), and field cooled cooling (FCC) c-axis transport properties. In addition, they also report magnetic relaxation measurements on the same samples to identify the c-axis dissipation mechanism. They observe a relaxation of the c-axis resistivity that follows the relaxation of the flux profile across the ab plane. By identifying the irreversible temperature vs. magnetic field for H // c, they construct a phase diagram of vortex states. Finally, they will discuss the implication of the phase diagram and the features related to the transport properties of the Josephson-coupled system and the role of pancake vortices in highly two-dimensional superconductors.

  6. Alignment of the Fibrin Network Within an Autologous Plasma Clot.

    PubMed

    Gessmann, Jan; Seybold, Dominik; Peter, Elvira; Schildhauer, Thomas Armin; Köller, Manfred

    2016-01-01

    Autologous plasma clots with longitudinally aligned fibrin fibers could serve as a scaffold for longitudinal axonal regrowth in cases of traumatic peripheral nerve injuries. Three different techniques for assembling longitudinally oriented fibrin fibers during the fibrin polymerization process were investigated as follows: fiber alignment was induced by the application of either a magnetic field or-as a novel approach-electric field or by the induction of orientated flow. Fiber alignment was characterized by scanning electron microscopy analysis followed by image processing using fast Fourier transformation (FFT). Besides FFT output images, area xmin to xmax, as well as full width at half maximum (FWHM) of the FFT graph plot peaks, was calculated to determine the relative degree of fiber alignment. In addition, fluorescently labeled human fibrinogen and mesenchymal stem cells (MSCs) were used to visualize fibrin and cell orientation in aligned and nonaligned plasma clots. Varying degrees of fiber alignment were achieved by the three different methods, with the electric field application producing the highest degree of fiber alignment. The embedded MSCs showed a longitudinal orientation in the electric field-aligned plasma clots. The key feature of this study is the ability to produce autologous plasma clots with aligned fibrin fibers using physical techniques. This orientated internal structure of an autologous biomaterial is promising for distinct therapeutic applications, such as a guiding structure for cell migration and growth dynamics.

  7. Fiber optics welder having movable aligning mirror

    DOEpatents

    Higgins, Robert W.; Robichaud, Roger E.

    1981-01-01

    A system for welding fiber optic waveguides together. The ends of the two fibers to be joined together are accurately, collinearly aligned in a vertical orientation and subjected to a controlled, diffuse arc to effect welding and thermal conditioning. A front-surfaced mirror mounted at a 45.degree. angle to the optical axis of a stereomicroscope mounted for viewing the junction of the ends provides two orthogonal views of the interface during the alignment operation.

  8. Quantum oscillation of the c-axis resistivity due to entrance of pancake vortices into micro-fabricated Bi 2Sr 2CaCu 2O 8+ δ intrinsic Josephson junctions

    NASA Astrophysics Data System (ADS)

    Kakeya, I.; Fukui, K.; Kawamata, K.; Yamamoto, T.; Kadowaki, K.

    2008-04-01

    The c-axis resistance in Bi2Sr2CaCu2O8+δ intrinsic Josephson junctions (IJJs) with areas of the ab-plane less than 2 μm2 were measured as functions of applied magnetic field and angle to the crystalline axes. When the magnetic field is tilted off from the lock-in state of Josephson vortices, several sharp dips are found. The separation between the dips approaches to the value corresponding to ϕ0 with further tilting the external magnetic field. This behavior is attributed to the penetration of a quantized pancake vortex into the tiny IJJ. This argument is further supported by the result that the c-axis resistance under magnetic fields parallel to the c-axis shows identical stepwise behavior.

  9. Vertically aligned ZnO nanorods of high crystalline and optical quality grown by dc reactive sputtering

    NASA Astrophysics Data System (ADS)

    Nandi, R.; Appani, Shravan K.; Major, S. S.

    2016-09-01

    ZnO nanorods were grown on Si and quartz substrates by direct current reactive magnetron sputtering of metallic zinc target in argon–oxygen ambient, without the use of any seed layer or catalyst. A combination of top-down and cross-sectional scanning electron microscopy studies have shown that the substrate temperature critically controls the growth behavior and morphology of ZnO films, eventually resulting in the growth of well aligned and separated ZnO nanorods at substrate temperature of ∼750 °C. High resolution x-ray diffraction studies of ZnO nanorods grown at 750 °C have shown that the nanorods are highly c-axis oriented and vertically aligned perpendicular to both Si and quartz substrates, and display small values of tilt and micro-strain, particularly in the case of Si substrate (1.26° and 4 × 10‑4, respectively). Cross-sectional transmission electron microscopy of ZnO nanorods demonstrates their single-crystalline nature and growth along [0002] direction. Room temperature photoluminescence spectra of ZnO nanorods display extremely high near-band-edge emission and weak defect emission due to point defects, compared to that of the ZnO films grown at lower substrate temperatures. The drastic enhancement of near-band-edge emission of ZnO nanorods (over two orders of magnitude) and strong suppression of defect emission are attributed to their high crystalline quality and absence of interface defects due to lateral coalescence.

  10. Vertically aligned ZnO nanorods of high crystalline and optical quality grown by dc reactive sputtering

    NASA Astrophysics Data System (ADS)

    Nandi, R.; Appani, Shravan K.; Major, S. S.

    2016-09-01

    ZnO nanorods were grown on Si and quartz substrates by direct current reactive magnetron sputtering of metallic zinc target in argon-oxygen ambient, without the use of any seed layer or catalyst. A combination of top-down and cross-sectional scanning electron microscopy studies have shown that the substrate temperature critically controls the growth behavior and morphology of ZnO films, eventually resulting in the growth of well aligned and separated ZnO nanorods at substrate temperature of ˜750 °C. High resolution x-ray diffraction studies of ZnO nanorods grown at 750 °C have shown that the nanorods are highly c-axis oriented and vertically aligned perpendicular to both Si and quartz substrates, and display small values of tilt and micro-strain, particularly in the case of Si substrate (1.26° and 4 × 10-4, respectively). Cross-sectional transmission electron microscopy of ZnO nanorods demonstrates their single-crystalline nature and growth along [0002] direction. Room temperature photoluminescence spectra of ZnO nanorods display extremely high near-band-edge emission and weak defect emission due to point defects, compared to that of the ZnO films grown at lower substrate temperatures. The drastic enhancement of near-band-edge emission of ZnO nanorods (over two orders of magnitude) and strong suppression of defect emission are attributed to their high crystalline quality and absence of interface defects due to lateral coalescence.

  11. Low-magnetic-field operations of intrinsic Josephson junctions with a long c-axis periodicity by artificial critical-current modulations

    NASA Astrophysics Data System (ADS)

    Sakai, Shigeki; Zhao, Xia

    2007-02-01

    Flux-flow cavity resonances in intrinsic Josephson junctions (IJJs) with long c-axis periodicity by artificial critical-current (Jc) modulation are studied numerically and theoretically. For an n-1-n-1-n-1-n IJJ system with n-layer high-Jc and one-layer low-Jc alternately stacked, numerical simulation confirms fluxon penetration only in the low-Jc junctions under proper low magnetic fields. The simulation also shows pronounced cavity-resonance steps in the I-V curves of the low-Jc junctions, meaning that fluxon dynamics can be generated under much lower magnetic fields, compared to the fields for usual IJJs with homogeneous Jc. A theoretical method for describing the flux-flow cavity-resonance properties is presented. The general disperse k-ω relationship shows that, at low-k regions, the critical-current-modulated junction system can be regarded as simple homogeneous stacked junctions with a new effective thickness and a new inductive coupling strength. For general-k cases, the cavity-resonant voltage steps on the I-V curves at various magnetic fields can be well indexed by integers, which means excellent agreement between the theoretical analysis and the numerical simulations.

  12. Dynamics of cell orientation

    NASA Astrophysics Data System (ADS)

    de, Rumi; Zemel, Assaf; Safran, Samuel A.

    2007-09-01

    Many physiological processes depend on the response of biological cells to mechanical forces generated by the contractile activity of the cell or by external stresses. Using a simple theoretical model that includes the forces due to both the mechanosensitivity of cells and the elasticity of the matrix, we predict the dynamics and orientation of cells in both the absence and presence of applied stresses. The model predicts many features observed in measurements of cellular forces and orientation including the increase with time of the cellular forces in the absence of applied stress and the consequent decrease of the force in the presence of quasi-static stresses. We also explain the puzzling observation of parallel alignment of cells for static and quasi-static stresses and of nearly perpendicular alignment for dynamically varying stresses. In addition, we predict the response of the cellular orientation to a sinusoidally varying applied stress as a function of frequency.

  13. Aligned mesoporous architectures and devices.

    SciTech Connect

    Brinker, C. Jeffrey; Lu, Yunfeng

    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.

  14. Intrinsic alignments of galaxies in the EAGLE and cosmo-OWLS simulations

    NASA Astrophysics Data System (ADS)

    Velliscig, Marco; Cacciato, Marcello; Schaye, Joop; Hoekstra, Henk; Bower, Richard G.; Crain, Robert A.; van Daalen, Marcel P.; Furlong, Michelle; McCarthy, I. G.; Schaller, Matthieu; Theuns, Tom

    2015-12-01

    We report results for the alignments of galaxies in the EAGLE and cosmo-OWLS hydrodynamical cosmological simulations as a function of galaxy separation (-1 ≤ log10(r/[ h-1 Mpc]) ≤ 2) and halo mass (10.7 ≤ log10(M200/[h-1 M⊙]) ≤ 15). We focus on two classes of alignments: the orientations of galaxies with respect to either the directions to, or the orientations of, surrounding galaxies. We find that the strength of the alignment is a strongly decreasing function of the distance between galaxies. For galaxies hosted by the most massive haloes in our simulations the alignment can remain significant up to ˜100 Mpc. Galaxies hosted by more massive haloes show stronger alignment. At a fixed halo mass, more aspherical or prolate galaxies exhibit stronger alignments. The spatial distribution of satellites is anisotropic and significantly aligned with the major axis of the main host halo. The major axes of satellite galaxies, when all stars are considered, are preferentially aligned towards the centre of the main host halo. The predicted projected direction-orientation alignment, ɛg+(rp), is in broad agreement with recent observations. We find that the orientation-orientation alignment is weaker than the orientation-direction alignment on all scales. Overall, the strength of galaxy alignments depends strongly on the subset of stars that are used to measure the orientations of galaxies and it is always weaker than the alignment of dark matter haloes. Thus, alignment models that use halo orientation as a direct proxy for galaxy orientation overestimate the impact of intrinsic galaxy alignments.

  15. Well-aligned polycrystalline lanthanum silicate oxyapatite grown by reactive diffusion between solid La2SiO5 and gases [SiO+1/2O2

    NASA Astrophysics Data System (ADS)

    Fukuda, Koichiro; Hasegawa, Ryo; Kitagawa, Takuya; Nakamori, Hiroshi; Asaka, Toru; Berghout, Abid; Béchade, Emilie; Masson, Olivier; Jouin, Jenny; Thomas, Philippe

    2016-03-01

    The c-axis-oriented polycrystalline lanthanum silicate oxyapatite, La9.48(Si5.89□0.11)O26 (□ denotes a vacancy in the Si site), was successfully prepared by the reactive diffusion between randomly grain-oriented La2SiO5 polycrystal and [SiO+1/2O2] gases at 1873 K in Ar atmosphere. The polycrystal was characterized using optical microscopy, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, micro-Raman spectroscopy, X-ray diffractometry, and impedance spectroscopy. The crystal structure (space group P63/m) showed the deficiency of Si site at ca. 1.9%. The bulk oxide-ion conductivity along the grain-alignment direction steadily increased from 9.2 × 10-3 to 1.17 × 10-2 S/cm with increasing temperature from 923 to 1073 K. The activation energy of conduction was 0.23(2) eV.

  16. MAVID multiple alignment server.

    PubMed

    Bray, Nicolas; Pachter, Lior

    2003-07-01

    MAVID is a multiple alignment program suitable for many large genomic regions. The MAVID web server allows biomedical researchers to quickly obtain multiple alignments for genomic sequences and to subsequently analyse the alignments for conserved regions. MAVID has been successfully used for the alignment of closely related species such as primates and also for the alignment of more distant organisms such as human and fugu. The server is fast, capable of aligning hundreds of kilobases in less than a minute. The multiple alignment is used to build a phylogenetic tree for the sequences, which is subsequently used as a basis for identifying conserved regions in the alignment. The server can be accessed at http://baboon.math.berkeley.edu/mavid/.

  17. Nearest Alignment Space Termination

    2006-07-13

    Near Alignment Space Termination (NAST) is the Greengenes algorithm that matches up submitted sequences with the Greengenes database to look for similarities and align the submitted sequences based on those similarities.

  18. Templating α-helical poly(L-lysine)/polyanion complexes by nanostructured uniaxially oriented ultrathin polyethylene films.

    PubMed

    Keller, Thomas F; Müller, Martin; Ouyang, Wuye; Zhang, Jian-Tao; Jandt, Klaus D

    2010-12-21

    We report a templating effect of uniaxially oriented melt-drawn polyethylene (MD-PE) films on α-helical poly(L-lysine)/poly(styrenesulfonate) (α-PLL/PSS) complexes deposited by the layer-by-layer (LBL) method. The melt-drawing process induced an MD-PE fiber texture consisting of nanoscale lamellar crystals embedded in amorphous regions on the MD-PE film surface whereby the common crystallographic c axis is the PE molecular chain direction parallel to the uniaxial melt-drawing direction. The MD-PE film and the α-PLL/PSS deposit were analyzed by atomic force microscopy (AFM) and in situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) using polarized light as a complementary method. Both methods revealed that α-PLL/PSS complexes adsorbed at the MD-PE surface were anisotropic and preferentially oriented perpendicular to the crystallographic c direction of the MD-PE film. Quantitatively, from AFM image analysis and ATR-FTIR dichroism of the amide II band of the α-PLL, mean cone opening angles of 12-18° for both rodlike α-PLL and the anisotropic α-PLL/PSS complexes with respect to the PE lamellae width direction were obtained. A model for the preferred alignment of α-PLL along the protruding PE lamellae is discussed, which is based on possible hydrophobic driving forces for the minimization of surface free energy at molecular and supermolecular topographic steps of the PE surface followed by electrostatic interactions between the interconnecting PSS and the α-PLL during layer-by-layer adsorption. This study elucidates the requirements and mechanisms involved in orienting biomolecules and may open up a path for designing templates to induce directed protein adsorption and cell growth by oriented polypeptide- or protein-modified PE surfaces.

  19. IAIMFAST: Alignment Implementation for Manufacturing

    2013-08-29

    AIMFAST is a software code used to align facets on a dish concentrator to a specific aimpoint strategy to minimize peak fluxes and maximize system optical performance. AIM FAST uses a large monitor to display fringe patterns, and a machine vision camera to image the reflection of these patterns in the subject dish mirrors. From these images, a detailed map of surface normals can be generated and compared to design or fitted mirror shapes. Thismore » fitted comparison is then used to develop a single vector representing the orientation of the facets relative to the design orientation, and provide near-real-time adjustment information to a communicating computer. The communicating computer can display adjustments or directly interface with adjustment tools.« less

  20. AIMFAST: Alignment Implementation for Manufacturing

    2012-09-13

    AIMFAST is a software code used to align facets on a dish concentrator to a specific aimpoint strategy to minimize peak fluxes and maximize system optical performance. AIMFAST uses a large monitor or projections screen to display fringe patterns, and a machine vision camera to image the reflection of these patterns in the subject dish mirrors. From these images, a detailed map of surface normals can be generated and compared to design or fitted mirrormore » shapes. This fitted comparison is then used to develop a single vector representing the orientation of the facets relative to the design orientation, and provide near-real-time adjustment information to a communicating computer. The communicating computer can display adjustments or directly interface with adjustment tools. The software for the communicating computer is specific to the implementation and is not a part of AIMFAST.« less

  1. IAIMFAST: Alignment Implementation for Manufacturing

    SciTech Connect

    Andraka, Charles E.

    2013-08-29

    AIMFAST is a software code used to align facets on a dish concentrator to a specific aimpoint strategy to minimize peak fluxes and maximize system optical performance. AIM FAST uses a large monitor to display fringe patterns, and a machine vision camera to image the reflection of these patterns in the subject dish mirrors. From these images, a detailed map of surface normals can be generated and compared to design or fitted mirror shapes. This fitted comparison is then used to develop a single vector representing the orientation of the facets relative to the design orientation, and provide near-real-time adjustment information to a communicating computer. The communicating computer can display adjustments or directly interface with adjustment tools.

  2. AIMFAST: Alignment Implementation for Manufacturing

    SciTech Connect

    2012-09-13

    AIMFAST is a software code used to align facets on a dish concentrator to a specific aimpoint strategy to minimize peak fluxes and maximize system optical performance. AIMFAST uses a large monitor or projections screen to display fringe patterns, and a machine vision camera to image the reflection of these patterns in the subject dish mirrors. From these images, a detailed map of surface normals can be generated and compared to design or fitted mirror shapes. This fitted comparison is then used to develop a single vector representing the orientation of the facets relative to the design orientation, and provide near-real-time adjustment information to a communicating computer. The communicating computer can display adjustments or directly interface with adjustment tools. The software for the communicating computer is specific to the implementation and is not a part of AIMFAST.

  3. The Alignment of Galaxy Structures

    NASA Astrophysics Data System (ADS)

    Biernacka, M.; Panko, E.; Bajan, K.; Godłowski, W.; Flin, P.

    2015-11-01

    We analyzed the orientation of the sample of ACO galaxy clusters. We examined the alignment in a subsample of 1056 galaxy structures taken from the Panko-Flin (2006) Catalog with known BM morphological types. We were looking for a correlation between the orientation of the cluster and the positions of neighboring clusters. The Binggeli effect (the excess of small values of the Δθ angles between the direction toward neighboring clusters and the cluster position angle) is observed, having a range up to about 45 h-1 Mpc. The strongest effect was found for elongated BM type I clusters. This is probably connected with the origins of the supergiant galaxy and with cluster formation along a long filament or plane in a supercluster.

  4. Orientation Studies of Recrystallized Vanadium Dioxide

    NASA Astrophysics Data System (ADS)

    Rivera, Felipe; Clemens, Mike; Burk, Laurel; Davis, Robert; Vanfleet, Richard

    2007-03-01

    Crystalline films and isolated vanadium dioxide particles were obtained through thermal annealing of amorphous vanadium dioxide thin films on silicon dioxide. Vanadium dioxide undergoes an insulator to metal transition near 66 ^oC. Orientation Imaging Microscopy (OIM) was used to study the phase and orientation of the crystals formed, as well as to differentiate from different vanadium oxide crystal structures. Kikuchi patterns for the tetragonal phase of vanadium dioxide were used for indexing as the Kikuchi patterns for the two phases are indistinguishable by OIM. There is a preferred orientation for the growth of these crystals with the c axis of the tetragonal phase parallel to the plane of the specimen. Resistance and Capacitance measurements on these films are being performed to study the electronic chracteristics of this phase transition. The results of this study will be presented.

  5. Orientation Studies of Recrystallized Vanadium Dioxide

    NASA Astrophysics Data System (ADS)

    Rivera, Felipe; Burk, Laurel; Davis, Robert; Vanfleet, Richard

    2006-10-01

    Crystalline films and isolated vanadium dioxide particles (up to 700nm in diameter) were obtained through thermal annealing of amorphous vanadium dioxide thin films on silicon dioxide. Vanadium dioxide undergoes a metal to insulator transition changing from a monoclinic to tetragonal phase near 66 ^o C. Orientation Imaging Microscopy (OIM) was used to study the phase and orientation of the crystals formed, as well as to differentiate from different vanadium oxide crystal structures. Kikuchi patterns for the tetragonal phase of vanadium dioxide were used for indexing as the Kikuchi patterns for the monoclinic phase are indistinguishable, by OIM, from those of the tetragonal phase. There is a preferred orientation for the growth of these crystals with the c axis in the plane of the specimen.

  6. Anisotropic fiber alignment in composite structures

    DOEpatents

    Graham, A.L.; Mondy, L.A.; Guell, D.C.

    1993-11-16

    High strength material composite structures are formed with oriented fibers to provide controlled anisotropic fibers. Fibers suspended in non-dilute concentrations (e.g., up to 20 volume percent for fibers having an aspect ratio of 20) in a selected medium are oriented by moving an axially spaced array of elements in the direction of desired fiber alignment. The array elements are generally perpendicular to the desired orientation. The suspension medium may also include sphere-like particles where the resulting material is a ceramic. 5 figures.

  7. Anisotropic fiber alignment in composite structures

    DOEpatents

    Graham, Alan L.; Mondy, Lisa A.; Guell, David C.

    1993-01-01

    High strength material composite structures are formed with oriented fibers to provide controlled anisotropic fibers. Fibers suspended in non-dilute concentrations (e.g., up to 20 volume percent for fibers having an aspect ratio of 20) in a selected medium are oriented by moving an axially spaced array of elements in the direction of desired fiber alignment. The array elements are generally perpendicular to the desired orientation. The suspension medium may also include sphere-like particles where the resulting material is a ceramic.

  8. Alignment Stage for a Cryogenic Dilatometer

    NASA Technical Reports Server (NTRS)

    Dudik, Matthew; Moore, Donald

    2005-01-01

    A three-degree-of-freedom alignment stage has been designed and built for use in a cryogenic dilatometer that is used to measure thermal strains. The alignment stage enables precise adjustments of the positions and orientations of optical components to be used in the measurements and, once adjustments have been completed, keeps the components precisely aligned during cryogenic-dilatometer operations that can last as long as several days. The alignment stage includes a case, a circular tilt/tip platform, and a variety of flexural couplings between the case and the platform, all machined from a single block of the low-thermal-expansion iron/nickel alloy Invar, in order to minimize effects of temperature gradients and to obtain couplings that are free of stiction and friction. There are three sets of flexural couplings clocked at equal angles of 120 degrees around the platform, constituting a three-point kinematic support system.

  9. Girder Alignment Plan

    SciTech Connect

    Wolf, Zackary; Ruland, Robert; LeCocq, Catherine; Lundahl, Eric; Levashov, Yurii; Reese, Ed; Rago, Carl; Poling, Ben; Schafer, Donald; Nuhn, Heinz-Dieter; Wienands, Uli; /SLAC

    2010-11-18

    The girders for the LCLS undulator system contain components which must be aligned with high accuracy relative to each other. The alignment is one of the last steps before the girders go into the tunnel, so the alignment must be done efficiently, on a tight schedule. This note documents the alignment plan which includes efficiency and high accuracy. The motivation for girder alignment involves the following considerations. Using beam based alignment, the girder position will be adjusted until the beam goes through the center of the quadrupole and beam finder wire. For the machine to work properly, the undulator axis must be on this line and the center of the undulator beam pipe must be on this line. The physics reasons for the undulator axis and undulator beam pipe axis to be centered on the beam are different, but the alignment tolerance for both are similar. In addition, the beam position monitor must be centered on the beam to preserve its calibration. Thus, the undulator, undulator beam pipe, quadrupole, beam finder wire, and beam position monitor axes must all be aligned to a common line. All relative alignments are equally important, not just, for example, between quadrupole and undulator. We begin by making the common axis the nominal beam axis in the girder coordinate system. All components will be initially aligned to this axis. A more accurate alignment will then position the components relative to each other, without incorporating the girder itself.

  10. Interstellar Dust Grain Alignment

    NASA Astrophysics Data System (ADS)

    Andersson, B.-G.; Lazarian, A.; Vaillancourt, John E.

    2015-08-01

    Interstellar polarization at optical-to-infrared wavelengths is known to arise from asymmetric dust grains aligned with the magnetic field. This effect provides a potentially powerful probe of magnetic field structure and strength if the details of the grain alignment can be reliably understood. Theory and observations have recently converged on a quantitative, predictive description of interstellar grain alignment based on radiative processes. The development of a general, analytical model for this radiative alignment torque (RAT) theory has allowed specific, testable predictions for realistic interstellar conditions. We outline the theoretical and observational arguments in favor of RAT alignment, as well as reasons the "classical" paramagnetic alignment mechanism is unlikely to work, except possibly for the very smallest grains. With further detailed characterization of the RAT mechanism, grain alignment and polarimetry promise to not only better constrain the interstellar magnetic field but also provide new information on the dust characteristics.

  11. Fragment oriented molecular shapes.

    PubMed

    Hain, Ethan; Camacho, Carlos J; Koes, David Ryan

    2016-05-01

    Molecular shape is an important concept in drug design and virtual screening. Shape similarity typically uses either alignment methods, which dynamically optimize molecular poses with respect to the query molecular shape, or feature vector methods, which are computationally less demanding but less accurate. The computational cost of alignment can be reduced by pre-aligning shapes, as is done with the Volumetric-Aligned Molecular Shapes (VAMS) method. Here, we introduce and evaluate fragment oriented molecular shapes (FOMS), where shapes are aligned based on molecular fragments. FOMS enables the use of shape constraints, a novel method for precisely specifying molecular shape queries that provides the ability to perform partial shape matching and supports search algorithms that function on an interactive time scale. When evaluated using the challenging Maximum Unbiased Validation dataset, shape constraints were able to extract significantly enriched subsets of compounds for the majority of targets, and FOMS matched or exceeded the performance of both VAMS and an optimizing alignment method of shape similarity search. PMID:27085751

  12. Liquid crystallinity driven highly aligned large graphene oxide composites

    SciTech Connect

    Lee, Kyung Eun; Oh, Jung Jae; Yun, Taeyeong; Kim, Sang Ouk

    2015-04-15

    Graphene is an emerging graphitic carbon materials, consisting of sp{sup 2} hybridized two dimensinal honeycomb structure. It has been widely studied to incorporate graphene with polymer to utilize unique property of graphene and reinforce electrical, mechanical and thermal property of polymer. In composite materials, orientation control of graphene significantly influences the property of composite. Until now, a few method has been developed for orientation control of graphene within polymer matrix. Here, we demonstrate facile fabrication of high aligned large graphene oxide (LGO) composites in polydimethylsiloxane (PDMS) matrix exploiting liquid crystallinity. Liquid crystalline aqueous dispersion of LGO is parallel oriented within flat confinement geometry. Freeze-drying of the aligned LGO dispersion and subsequent infiltration with PDMS produce highly aligned LGO/PDMS composites. Owing to the large shape anisotropy of LGO, liquid crystalline alignment occurred at low concentration of 2 mg/ml in aqueous dispersion, which leads to the 0.2 wt% LGO loaded composites. - Graphical abstract: Liquid crystalline LGO aqueous dispersions are spontaneous parallel aligned between geometric confinement for highly aligned LGO/polymer composite fabrication. - Highlights: • A simple fabrication method for highly aligned LGO/PDMS composites is proposed. • LGO aqueous dispersion shows nematic liquid crystalline phase at 0.8 mg/ml. • In nematic phase, LGO flakes are highly aligned by geometric confinement. • Infiltration of PDMS into freeze-dried LGO allows highly aligned LGO/PDMS composites.

  13. Smart and precise alignment of optical systems

    NASA Astrophysics Data System (ADS)

    Langehanenberg, Patrik; Heinisch, Josef; Stickler, Daniel

    2013-09-01

    For the assembly of any kind of optical systems the precise centration of every single element is of particular importance. Classically the precise alignment of optical components is based on the precise centering of all components to an external axis (usually a high-precision rotary spindle axis). Main drawback of this timeconsuming process is that it is significantly sensitive to misalignments of the reference (e.g. the housing) axis. In order to facilitate process in this contribution we present a novel alignment strategy for the TRIOPTICS OptiCentric® instrument family that directly aligns two elements with respect to each other by measuring the first element's axis and using this axis as alignment reference without the detour of considering an external reference. According to the optical design any axis in the system can be chosen as target axis. In case of the alignment to a barrel this axis is measured by using a distance sensor (e.g., the classically used dial indicator). Instead of fine alignment the obtained data is used for the calculation of its orientation within the setup. Alternatively, the axis of an optical element (single lens or group of lenses) whose orientation is measured with the standard OptiCentric MultiLens concept can be used as a reference. In the instrument's software the decentering of the adjusting element to the calculated axis is displayed in realtime and indicated by a target mark that can be used for the manual alignment. In addition, the obtained information can also be applied for active and fully automated alignment of lens assemblies with the help of motorized actuators.

  14. Mechanical alignment of particles for use in fabricating superconducting and permanent magnetic materials

    DOEpatents

    Nellis, William J.; Maple, M. Brian

    1992-01-01

    A method for mechanically aligning oriented superconducting or permanently magnetic materials for further processing into constructs. This pretreatment optimizes the final crystallographic orientation and, thus, properties in these constructs. Such materials as superconducting fibers, needles and platelets are utilized.

  15. Crystallographic Orientation of Cuttlebone Shield Determined by Electron Backscatter Diffraction

    NASA Astrophysics Data System (ADS)

    Cusack, Maggie; Chung, Peter

    2014-01-01

    In common with many cephalopod mollusks, cuttlefish produce an internal biomineral buoyancy device. This cuttlebone is analogous to a surf board in shape and structure, providing rigidity and a means of controlling buoyancy. The cuttlebone is composed of calcium carbonate in the form of aragonite and comprises an upper dorsal shield and a lower lamellar matrix. The lamellar matrix comprises layers of chambers with highly corrugated walls. The dorsal shield comprises bundles of aragonite needles stacked on top of each other. Electron backscatter diffraction analyses of the dorsal shield reveal that the c-axis of aragonite is parallel with the long axis of the needles in the bundles such that any spread in crystallographic orientation is consistent with the spread in orientation of the fibers as they radiate to form the overall structure of the dorsal shield. This arrangement of c-axis coincident with the long axis of the biomineral structure is similar to the arrangement in corals and in contrast to the situation in the molluskan aragonite nacre of brachiopod calcite where the c-axis is perpendicular to the aragonite tablet or calcite fiber, respectively.

  16. Control of magnetization reversal in oriented strontium ferrite thin films

    SciTech Connect

    Roy, Debangsu Anil Kumar, P. S.

    2014-02-21

    Oriented Strontium Ferrite films with the c axis orientation were deposited with varying oxygen partial pressure on Al{sub 2}O{sub 3}(0001) substrate using Pulsed Laser Deposition technique. The angle dependent magnetic hysteresis, remanent coercivity, and temperature dependent coercivity had been employed to understand the magnetization reversal of these films. It was found that the Strontium Ferrite thin film grown at lower (higher) oxygen partial pressure shows Stoner-Wohlfarth type (Kondorsky like) reversal. The relative importance of pinning and nucleation processes during magnetization reversal is used to explain the type of the magnetization reversal with different oxygen partial pressure during growth.

  17. Vertically Oriented Growth of GaN Nanorods on Si Using Graphene as an Atomically Thin Buffer Layer.

    PubMed

    Heilmann, Martin; Munshi, A Mazid; Sarau, George; Göbelt, Manuela; Tessarek, Christian; Fauske, Vidar T; van Helvoort, Antonius T J; Yang, Jianfeng; Latzel, Michael; Hoffmann, Björn; Conibeer, Gavin; Weman, Helge; Christiansen, Silke

    2016-06-01

    The monolithic integration of wurtzite GaN on Si via metal-organic vapor phase epitaxy is strongly hampered by lattice and thermal mismatch as well as meltback etching. This study presents single-layer graphene as an atomically thin buffer layer for c-axis-oriented growth of vertically aligned GaN nanorods mediated by nanometer-sized AlGaN nucleation islands. Nanostructures of similar morphology are demonstrated on graphene-covered Si(111) as well as Si(100). High crystal and optical quality of the nanorods are evidenced through scanning transmission electron microscopy, micro-Raman, and cathodoluminescence measurements supported by finite-difference time-domain simulations. Current-voltage characteristics revealed high vertical conduction of the as-grown GaN nanorods through the Si substrates. These findings are substantial to advance the integration of GaN-based devices on any substrates of choice that sustains the GaN growth temperatures, thereby permitting novel designs of GaN-based heterojunction device concepts.

  18. Vertically Oriented Growth of GaN Nanorods on Si Using Graphene as an Atomically Thin Buffer Layer.

    PubMed

    Heilmann, Martin; Munshi, A Mazid; Sarau, George; Göbelt, Manuela; Tessarek, Christian; Fauske, Vidar T; van Helvoort, Antonius T J; Yang, Jianfeng; Latzel, Michael; Hoffmann, Björn; Conibeer, Gavin; Weman, Helge; Christiansen, Silke

    2016-06-01

    The monolithic integration of wurtzite GaN on Si via metal-organic vapor phase epitaxy is strongly hampered by lattice and thermal mismatch as well as meltback etching. This study presents single-layer graphene as an atomically thin buffer layer for c-axis-oriented growth of vertically aligned GaN nanorods mediated by nanometer-sized AlGaN nucleation islands. Nanostructures of similar morphology are demonstrated on graphene-covered Si(111) as well as Si(100). High crystal and optical quality of the nanorods are evidenced through scanning transmission electron microscopy, micro-Raman, and cathodoluminescence measurements supported by finite-difference time-domain simulations. Current-voltage characteristics revealed high vertical conduction of the as-grown GaN nanorods through the Si substrates. These findings are substantial to advance the integration of GaN-based devices on any substrates of choice that sustains the GaN growth temperatures, thereby permitting novel designs of GaN-based heterojunction device concepts. PMID:27124605

  19. Epitaxial aluminum-doped zinc oxide thin films on sapphire. 1: Effect of substrate orientation

    SciTech Connect

    Srikant, V.; Sergo, V.; Clarke, D.R.

    1995-07-01

    Epitaxial thin films of Al-doped zinc oxide have been grown on sapphire substrates by pulsed laser ablation. The effect of substrate temperature, background pressure of oxygen, and substrate orientation (A, M, R, C) on the orientation relationships between ZnO and sapphire have been evaluated using on- and off-axis X-ray diffractometry. Under all growth conditions zinc oxide, on A- and C-plane sapphire, grew with the c-axis perpendicular to the substrate. In contrast, on M and R orientations of sapphire, ZnO grew with its c-axis parallel or perpendicular to the substrate depending on the substrate temperature and background pressure employed during growth. In all cases only one unique in-plane relationship between the sapphire substrate and the zinc oxide film was found with the exception of the M-plane at high substrate temperatures.

  20. Critical currents of aligned grains of Tl-Ba-Ca-Cu-O compounds

    NASA Technical Reports Server (NTRS)

    Fang, M. M.; Finnemore, D. K.; Farrell, D. E.; Bansal, N. R.

    1989-01-01

    A study of irreversibility in the magnetization curves of Tl2Ba2Ca2Cu3O10 and Tl2Ba2Ca1Cu2O8 was undertaken to determine the intragranular critical currents and the effects of flux-creep in grain-aligned samples of these materials. For fields of greater than 0.3 T, and H parallel to c axis, the critical supercurrent falls approximately exponentially with both magnetic field and temperature. Flux-creep is found to be linear in the logarithm of time at low fields over a wide temperature range.

  1. Further solar alignments of Greek Byzantine churches

    NASA Astrophysics Data System (ADS)

    Liritzis, I.; Vasiliou, H.

    Following the recent work on the solar alignment of Greek byzantine churches (Liritzis and Vassiliou 2006 a,b,c) the solar orientations of twenty one more churches are presented. The question examined is if the day of solar rise across the eastern direction of the church is related with the feast day of Patron Saint. Measurements were carried out with magnetic compass, inclinometer, portable GPS and appropriate corrections for the solar declination. The alignments towards eastern sunrise were examined for various angular altitudes of the perceptible horizon. At least for all Rhodean churches the patron's day is met when sun oblique path crosses horizon a few degrees beyond the intersection of extrapolated eastern axis of the church with horizons skyline. Therefore, taken the orientation as the glitter of first sunrays -early dawn- correlation of thirteen present churches are aligned near the autumnal equinox, three have relation with the feast of patron saint, four are related to the other important feast of Christianity and one seem orientated randomly. However accounting for a due east sun position a few degrees above horizon in early liturgy hours (6:30 - 9:30 am) all the Rhodean alignments coincides with Saint's name day.

  2. Alignment Cube with One Diffractive Face

    NASA Technical Reports Server (NTRS)

    Ohl, Raymond G.; Sampler, Henry P.; Strojny, Carl R.; Hagopian, John G.; McMann, Joseph C.

    2006-01-01

    An enhanced alignment cube has been invented for use in a confined setting (e.g., a cryogenic chamber) in which optical access may be limited to a single line of sight. Whereas traditional alignment-cube practice entails the use of two theodolites aimed along two lines of sight, the enhanced alignment cube yields complete alignment information through use of a single theodolite aimed along a single line of sight. Typically, an alignment cube is placed in contact with a datum surface or other reference feature on a scientific instrument during assembly or testing of the instrument. The alignment cube is then used in measuring a small angular deviation of the feature from a precise required orientation. Commonly, the deviation is expressed in terms of rotations (Rx,Ry,Rz) of the cube about the corresponding Cartesian axes (x,y,z). In traditional practice, in order to measure all three rotations, it is necessary to use two theodolites aimed at two orthogonal faces of the alignment cube, as shown in the upper part of the figure. To be able to perform such a measurement, one needs optical access to these two faces. In the case of an alignment cube inside a cryogenic chamber or other enclosed space, the optical-access requirement translates to a requirement for two windows located along the corresponding two orthogonal lines of sight into the chamber. In a typical application, it is difficult or impossible to provide two windows. The present enhanced version of the alignment cube makes it possible to measure all three rotations by use of a single line of sight, thereby obviating a second window.

  3. Horizontal carbon nanotube alignment.

    PubMed

    Cole, Matthew T; Cientanni, Vito; Milne, William I

    2016-09-21

    The production of horizontally aligned carbon nanotubes offers a rapid means of realizing a myriad of self-assembled near-atom-scale technologies - from novel photonic crystals to nanoscale transistors. The ability to reproducibly align anisotropic nanostructures has huge technological value. Here we review the present state-of-the-art in horizontal carbon nanotube alignment. For both in and ex situ approaches, we quantitatively assess the reported linear packing densities alongside the degree of alignment possible for each of these core methodologies. PMID:27546174

  4. Horizontal carbon nanotube alignment.

    PubMed

    Cole, Matthew T; Cientanni, Vito; Milne, William I

    2016-09-21

    The production of horizontally aligned carbon nanotubes offers a rapid means of realizing a myriad of self-assembled near-atom-scale technologies - from novel photonic crystals to nanoscale transistors. The ability to reproducibly align anisotropic nanostructures has huge technological value. Here we review the present state-of-the-art in horizontal carbon nanotube alignment. For both in and ex situ approaches, we quantitatively assess the reported linear packing densities alongside the degree of alignment possible for each of these core methodologies.

  5. Orthodontics and Aligners

    MedlinePlus

    ... Repairing Chipped Teeth Teeth Whitening Tooth-Colored Fillings Orthodontics and Aligners Straighten teeth for a healthier smile. Orthodontics When consumers think about orthodontics, braces are the ...

  6. Tidal alignment of galaxies

    NASA Astrophysics Data System (ADS)

    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.

  7. Alignability of Optical Interconnects

    NASA Astrophysics Data System (ADS)

    Beech, Russell Scott

    With the continuing drive towards higher speed, density, and functionality in electronics, electrical interconnects become inadequate. Due to optics' high speed and bandwidth, freedom from capacitive loading effects, and freedom from crosstalk, optical interconnects can meet more stringent interconnect requirements. But, an optical interconnect requires additional components, such as an optical source and detector, lenses, holographic elements, etc. Fabrication and assembly of an optical interconnect requires precise alignment of these components. The successful development and deployment of optical interconnects depend on how easily the interconnect components can be aligned and/or how tolerant the interconnect is to misalignments. In this thesis, a method of quantitatively specifying the relative difficulty of properly aligning an optical interconnect is described. Ways of using this theory of alignment to obtain design and packaging guidelines for optical interconnects are examined. The measure of the ease with which an optical interconnect can be aligned, called the alignability, uses the efficiency of power transfer as a measure of alignment quality. The alignability is related to interconnect package design through the overall cost measure, which depends upon various physical parameters of the interconnect, such as the cost of the components and the time required for fabrication and alignment. Through a mutual dependence on detector size, the relationship between an interconnect's alignability and its bandwidth, signal-to-noise ratio, and bit-error -rate is examined. The results indicate that a range of device sizes exists for which given performance threshold values are satisfied. Next, the alignability of integrated planar-optic backplanes is analyzed in detail. The resulting data show that the alignability can be optimized by varying the substrate thickness or the angle of reflection. By including the effects of crosstalk, in a multi-channel backplane, the

  8. Periodic c-axis modulation and crystallographic Fourier analysis of Bi 2Sr 2Ca nCu n+1O 6+2n+x ( n=0,1) single crystals with excess Bi

    NASA Astrophysics Data System (ADS)

    Ariosa, D.; Berger, H.; Schmauder, T.; Pavuna, D.; Margaritondo, G.; Christensen, S.; Kelley, R. J.; Onellion, M.

    2001-04-01

    We report on a distortion of Bi 2Sr 2Ca nCu n+1O 6+2n+x ( n=0,1) single crystals, perpendicular to the CuO 2 planes (the c-axis), for non-stoichiometric samples containing an excess of Bi. The distortion involves two parts: (a) symmetric displacements in the SrO and CuO 2 planes along the c-axis, and (b) an antisymmetric longitudinal compressive wave. The latter is revealed by observing odd harmonics in the X-ray diffraction (XRD) data. Such odd harmonics are typically extinguished for the I4/mmm space group of the exact stoichiometric phase. The antisymmetric compressive wave is reported for both BSCCO-2201 and BSCCO-2212 Bi excess samples, as well as for La-doped BSCCO-2201 samples. We have performed XRD model calculations for all samples studied, combined with Fourier analysis of the periodic c-axis modulation. The antisymmetric compressive wave was proven by reconstructing the atomic position profile from the intensity of odd XRD peaks caused by this commensurate modulation. Our results indicate preferential ordered substitution of Bi ions on nominally Sr ion positions. We also discuss implications for oxygen mobility, reversible sample doping, and electronic properties.

  9. Liquid crystallinity driven highly aligned large graphene oxide composites

    NASA Astrophysics Data System (ADS)

    Lee, Kyung Eun; Oh, Jung Jae; Yun, Taeyeong; Kim, Sang Ouk

    2015-04-01

    Graphene is an emerging graphitic carbon materials, consisting of sp2 hybridized two dimensinal honeycomb structure. It has been widely studied to incorporate graphene with polymer to utilize unique property of graphene and reinforce electrical, mechanical and thermal property of polymer. In composite materials, orientation control of graphene significantly influences the property of composite. Until now, a few method has been developed for orientation control of graphene within polymer matrix. Here, we demonstrate facile fabrication of high aligned large graphene oxide (LGO) composites in polydimethylsiloxane (PDMS) matrix exploiting liquid crystallinity. Liquid crystalline aqueous dispersion of LGO is parallel oriented within flat confinement geometry. Freeze-drying of the aligned LGO dispersion and subsequent infiltration with PDMS produce highly aligned LGO/PDMS composites. Owing to the large shape anisotropy of LGO, liquid crystalline alignment occurred at low concentration of 2 mg/ml in aqueous dispersion, which leads to the 0.2 wt% LGO loaded composites.

  10. EDITORIAL: Optical orientation Optical orientation

    NASA Astrophysics Data System (ADS)

    SAME ADDRESS *, Yuri; Landwehr, Gottfried

    2008-11-01

    priority of the discovery in the literature, which was partly caused by the existence of the Iron Curtain. I had already enjoyed contact with Boris in the 1980s when the two volumes of Landau Level Spectroscopy were being prepared [2]. He was one of the pioneers of magneto-optics in semiconductors. In the 1950s the band structure of germanium and silicon was investigated by magneto-optical methods, mainly in the United States. No excitonic effects were observed and the band structure parameters were determined without taking account of excitons. However, working with cuprous oxide, which is a direct semiconductor with a relative large energy gap, Zakharchenya and his co-worker Seysan showed that in order to obtain correct band structure parameters, it is necessary to take excitons into account [3]. About 1970 Boris started work on optical orientation. Early work by Hanle in Germany in the 1920s on the depolarization of luminescence in mercury vapour by a transverse magnetic field was not appreciated for a long time. Only in the late 1940s did Kastler and co-workers in Paris begin a systematic study of optical pumping, which led to the award of a Nobel prize. The ideas of optical pumping were first applied by Georges Lampel to solid state physics in 1968. He demonstrated optical orientation of free carriers in silicon. The detection method was nuclear magnetic resonance; optically oriented free electrons dynamically polarized the 29Si nuclei of the host lattice. The first optical detection of spin orientation was demonstrated by with the III-V semiconductor GaSb by Parsons. Due to the various interaction mechanisms of spins with their environment, the effects occurring in semiconductors are naturally more complex than those in atoms. Optical detection is now the preferred method to detect spin alignment in semiconductors. The orientation of spins in crystals pumped with circularly polarized light is deduced from the degree of circular polarization of the recombination

  11. An implicit spatial memory alignment effect.

    PubMed

    Cerles, Mélanie; Gomez, Alice; Rousset, Stéphane

    2015-09-01

    The memory alignment effect is the advantage of reasoning from a perspective which is aligned with the frame of reference used to encode an environment in memory. It usually occurs when participants have to consciously take a perspective to perform a spatial memory task. The present experiment assesses whether the memory alignment effect can occur without requiring to consciously take a given perspective, when the misaligned perspective is only perceptively provided. In others words, does the memory alignment effect still arise when it is only implicitly prompted? Thirty participants learned a sequence of four objects' positions in a room from a north-as-up survey perspective. During the testing phase, they had to point to the direction of a target object from another object ('the reference') with a fixed north-up orientation. The background behind the reference object displayed either a uniform color (control condition) or a misaligned ground-level perspective. The latter displayed a reference object's position information which was either congruent with the studied environment (congruent misaligned condition) or incongruent (incongruent misaligned condition). Mean pointing errors were higher in the congruent misaligned condition than in the control condition, whereas the incongruent misaligned condition did not differ from the control one. The present study shows that the memory alignment effect can arise without requiring a conscious misaligned perspective taking. Moreover, the perceived misaligned perspective must share the same spatial content as the memorized spatial representation in order to induce an alignment effect. PMID:26233526

  12. Hole-Aligning Tool

    NASA Technical Reports Server (NTRS)

    Collins, Frank A.; Saude, Frank; Sep, Martin J.

    1996-01-01

    Tool designed for use in aligning holes in plates or other structural members to be joined by bolt through holes. Holes aligned without exerting forces perpendicular to planes of holes. Tool features screw-driven-wedge design similar to (but simpler than) that of some automotive exhaust-pipe-expanding tools.

  13. Alignment of liquid crystals doped with nickel nanoparticles containing different morphologies.

    PubMed

    Zhao, Dongyu; Zhou, Wei; Cui, Xiaopeng; Tian, Yu; Guo, Lin; Yang, Huai

    2011-12-22

    Uniform homeotropic and homogeneous alignment of liquid crystals (LCs) is facilely achieved by dispersing Ni nanoparticles (Ni NPs) into the LCs. The alignment mode depends on the morphology of the Ni NPs. The mechanism of NP-induced LC alignment is elucidated clearly, indicating that the perfect orientation arises from the adsorption of Ni NPs on the substrate. PMID:22102432

  14. Corrective optics space telescope axial replacement alignment system

    NASA Astrophysics Data System (ADS)

    Slusher, Robert B.; Satter, Michael J.; Kaplan, Michael L.; Martella, Mark A.; Freymiller, Ed D.; Buzzetta, Victor

    1993-10-01

    To facilitate the accurate placement and alignment of the corrective optics space telescope axial replacement (COSTAR) structure, mechanisms, and optics, the COSTAR Alignment System (CAS) has been designed and assembled. It consists of a 20-foot optical bench, support structures for holding and aligning the COSTAR instrument at various stages of assembly, a focal plane target fixture (FPTF) providing an accurate reference to the as-built Hubble Space Telescope (HST) focal plane, two alignment translation stages with interchangeable alignment telescopes and alignment lasers, and a Zygo Mark IV interferometer with a reference sphere custom designed to allow accurate double-pass operation of the COSTAR correction optics. The system is used to align the fixed optical bench (FOB), the track, the deployable optical bench (DOB), the mechanisms, and the optics to ensure that the correction mirrors are all located in the required positions and orientations on-orbit after deployment. In this paper, the layout of the CAS is presented and the various alignment operations are listed along with the relevant alignment requirements. In addition, calibration of the necessary support structure elements and alignment aids is described, including the two-axis translation stages, the latch positions, the FPTF, and the COSTAR-mounted alignment cubes.

  15. XRD analysis on ZnO and Au film crystal orientation in ZnO/Au/SiO2 structure

    NASA Astrophysics Data System (ADS)

    Qin, Huibin; Yu, Hong; Chen, Yunxang

    2000-05-01

    The orientation of the Zn/Au/Si structure was examined by XRD. The experiment showed that the ZnO/Au/Si films deposited by magnetron sputtering were possessed of a preferred orientation in C axis perpendicular to the film surface. The (111) of Au film was possessed of a preferred <111> orientation which was perpendicular to the film surface also. The XRD (theta) approximately 2 (theta) scan irradiated that there were only (001) peaks in excellent orientated ZnO films. The rock cure scan demonstrated that the C axis of ZnO film was not exactly perpendicular to the surface, the angular divergence was about 2 degree(s), and the space divergence angle about 1.5 degree(s). Expert the (kkk) main peaks of Au film there were weak diffraction peaks, such as (002), (022), and (311) peaks. The phenomena indicated that in Au film there was not only (111) plane in parallel to the surface of substrate. As there was only 12% dis-matching between Au (111) and ZnO (001), the Au (111) oriented film was facilitated for the ZnO (001) orientation in C axis and deposing parameters adjustment.

  16. Orientation-crowding within contours.

    PubMed

    Glen, James C; Dakin, Steven C

    2013-01-01

    We examined how crowding (the breakdown of object recognition in the periphery caused by interference from "clutter") depends on the global arrangement of target and distracting flanker elements. Specifically we probed orientation discrimination using a near-vertical target Gabor flanked by two vertical distractor Gabors (one above and one below the target). By applying variable (opposite-sign) horizontal offsets to the positions of the two flankers we arranged the elements so that on some trials they formed contours with the target and on others they did not. While the presence of flankers generally elevated orientation discrimination thresholds for the target we observe maximal crowding not when flanker and targets were co-aligned but when a small spatial offset was applied to flanker location, so that contours formed between flanker and targets only when the target orientation was cued. We also report that observers' orientation judgments are biased, with target orientation appearing either attracted or repulsed by the global/contour orientation. A second experiment reveals that the sign of this effect is dependent both on observer and on eccentricity. In general, the magnitude of repulsion is reduced with eccentricity but whether this becomes attraction (of element orientation to contour orientation) is dependent on observer. We note however that across observers and eccentricities, the magnitude of repulsion correlates positively with the amount of release from crowding observed with co-aligned targets and flankers, supporting the notion of fluctuating bias as the basis for elevated crowding within contours. PMID:23857951

  17. Precision alignment device

    DOEpatents

    Jones, Nelson E.

    1990-01-01

    Apparatus for providing automatic alignment of beam devices having an associated structure for directing, collimating, focusing, reflecting, or otherwise modifying the main beam. A reference laser is attached to the structure enclosing the main beam producing apparatus and produces a reference beam substantially parallel to the main beam. Detector modules containing optical switching devices and optical detectors are positioned in the path of the reference beam and are effective to produce an electrical output indicative of the alignment of the main beam. This electrical output drives servomotor operated adjustment screws to adjust the position of elements of the structure associated with the main beam to maintain alignment of the main beam.

  18. Precision alignment device

    DOEpatents

    Jones, N.E.

    1988-03-10

    Apparatus for providing automatic alignment of beam devices having an associated structure for directing, collimating, focusing, reflecting, or otherwise modifying the main beam. A reference laser is attached to the structure enclosing the main beam producing apparatus and produces a reference beam substantially parallel to the main beam. Detector modules containing optical switching devices and optical detectors are positioned in the path of the reference beam and are effective to produce an electrical output indicative of the alignment of the main beam. This electrical output drives servomotor operated adjustment screws to adjust the position of elements of the structure associated with the main beam to maintain alignment of the main beam. 5 figs.

  19. Galaxy Alignments: An Overview

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    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.

  20. Radiative Grain Alignment

    NASA Astrophysics Data System (ADS)

    Andersson, B. G.

    2015-12-01

    Polarization due to aligned dust grains was discovered in the interstellar medium more than 60 years ago. A quantitative, observationally well tested theory of the phenomenon has finally emerged in the last decade, promising not only an improved understanding of interstellar magnetic fields, but new tools for studying the dust environments and grain characteristics. This Radiative Alignment Torque (RAT) theory also has many potential applications in solar system physics, including for comet dust characteristics. I will review the main aspects of the theory and the observational tests performed to date, as well as some of the new possibilities for using polarization as a tool to study dust and its environment, with RAT alignment.

  1. Hybrid vehicle motor alignment

    DOEpatents

    Levin, Michael Benjamin

    2001-07-03

    A rotor of an electric motor for a motor vehicle is aligned to an axis of rotation for a crankshaft of an internal combustion engine having an internal combustion engine and an electric motor. A locator is provided on the crankshaft, a piloting tool is located radially by the first locator to the crankshaft. A stator of the electric motor is aligned to a second locator provided on the piloting tool. The stator is secured to the engine block. The rotor is aligned to the crankshaft and secured thereto.

  2. Pairwise Sequence Alignment Library

    SciTech Connect

    Jeff Daily, PNNL

    2015-05-20

    Vector extensions, such as SSE, have been part of the x86 CPU since the 1990s, with applications in graphics, signal processing, and scientific applications. Although many algorithms and applications can naturally benefit from automatic vectorization techniques, there are still many that are difficult to vectorize due to their dependence on irregular data structures, dense branch operations, or data dependencies. Sequence alignment, one of the most widely used operations in bioinformatics workflows, has a computational footprint that features complex data dependencies. The trend of widening vector registers adversely affects the state-of-the-art sequence alignment algorithm based on striped data layouts. Therefore, a novel SIMD implementation of a parallel scan-based sequence alignment algorithm that can better exploit wider SIMD units was implemented as part of the Parallel Sequence Alignment Library (parasail). Parasail features: Reference implementations of all known vectorized sequence alignment approaches. Implementations of Smith Waterman (SW), semi-global (SG), and Needleman Wunsch (NW) sequence alignment algorithms. Implementations across all modern CPU instruction sets including AVX2 and KNC. Language interfaces for C/C++ and Python.

  3. Pairwise Sequence Alignment Library

    2015-05-20

    Vector extensions, such as SSE, have been part of the x86 CPU since the 1990s, with applications in graphics, signal processing, and scientific applications. Although many algorithms and applications can naturally benefit from automatic vectorization techniques, there are still many that are difficult to vectorize due to their dependence on irregular data structures, dense branch operations, or data dependencies. Sequence alignment, one of the most widely used operations in bioinformatics workflows, has a computational footprintmore » that features complex data dependencies. The trend of widening vector registers adversely affects the state-of-the-art sequence alignment algorithm based on striped data layouts. Therefore, a novel SIMD implementation of a parallel scan-based sequence alignment algorithm that can better exploit wider SIMD units was implemented as part of the Parallel Sequence Alignment Library (parasail). Parasail features: Reference implementations of all known vectorized sequence alignment approaches. Implementations of Smith Waterman (SW), semi-global (SG), and Needleman Wunsch (NW) sequence alignment algorithms. Implementations across all modern CPU instruction sets including AVX2 and KNC. Language interfaces for C/C++ and Python.« less

  4. Alignments of galaxies within cosmic filaments from SDSS DR7

    SciTech Connect

    Zhang, Youcai; Yang, Xiaohu; Wang, Huiyuan; Wang, Lei; Mo, H. J.; Van den Bosch, Frank C. E-mail: xyang@sjtu.edu.cn

    2013-12-20

    Using a sample of galaxy groups selected from the Sloan Digital Sky Survey Data Release 7, we examine the alignment between the orientation of galaxies and their surrounding large-scale structure in the context of the cosmic web. The latter is quantified using the large-scale tidal field, reconstructed from the data using galaxy groups above a certain mass threshold. We find that the major axes of galaxies in filaments tend to be preferentially aligned with the directions of the filaments, while galaxies in sheets have their major axes preferentially aligned parallel to the plane of the sheets. The strength of this alignment signal is strongest for red, central galaxies, and in good agreement with that of dark matter halos in N-body simulations. This suggests that red, central galaxies are well aligned with their host halos, in quantitative agreement with previous studies based on the spatial distribution of satellite galaxies. There is a luminosity and mass dependence that brighter and more massive galaxies in filaments and sheets have stronger alignment signals. We also find that the orientation of galaxies is aligned with the eigenvector associated with the smallest eigenvalue of the tidal tensor. These observational results indicate that galaxy formation is affected by large-scale environments and strongly suggest that galaxies are aligned with each other over scales comparable to those of sheets and filaments in the cosmic web.

  5. Superconductivity-induced effect on c-axis electronic Raman scattering in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} single crystals

    SciTech Connect

    Liu, H. L.; Blumberg, G.; Klein, M. V.; Guptasarma, P.; Hinks, D. G.

    1999-09-01

    We report on the c-axis-polarized electronic Raman scattering of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} single crystals with various oxygen concentrations. Below T{sub c}, there is a low-energy redistribution of the electronic continuum and the presence of a 2{delta} peak-like feature for all doping levels studied. The superconductivity-induced effect is also accumulated from frequencies as high as 40{delta}. (c) 1999 American Institute of Physics.

  6. Persistence of the superconducting condensate far above the critical temperature of YBa2(Cu,Zn)3O(y) revealed by c-axis optical conductivity measurements for several Zn concentrations and carrier doping levels.

    PubMed

    Uykur, Ece; Tanaka, Kiyohisa; Masui, Takahiko; Miyasaka, Shigeki; Tajima, Setsuko

    2014-03-28

    The superconductivity precursor phenomena in high temperature cuprate superconductors is studied by direct measurements of the superconducting condensate with the use of the c-axis optical conductivity of YBa2(Cu1-xZnx)3Oy for several doping levels (p) as well as for several Zn concentrations. Both the real and imaginary parts of the optical conductivity clearly show that the superconducting carriers persist up to the high temperatures Tp that is higher than the critical temperature Tc but lower than the pseudogap temperature T*. Tp increases with reducing doping level like T*, but decreases with Zn substitution unlike T*.

  7. Making Macroscopic Assemblies of Aligned Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Smalley, Richard E.; Colbert, Daniel T.; Smith, Ken A.; Walters, Deron A.; Casavant, Michael J.; Qin, Xiaochuan; Yakobson, Boris; Hauge, Robert H.; Saini, Rajesh Kumar; Chiung, Wan-Ting; Huffman, Charles B.

    2005-01-01

    A method of aligning and assembling single-wall carbon nanotubes (SWNTs) to fabricate macroscopic structures has been invented. The method entails suspending SWNTs in a fluid, orienting the SWNTs by use of a magnetic and/or electric field, and then removing the aligned SWNTs from suspension in such a way as to assemble them while maintaining the alignment. SWNTs are essentially tubular extensions of fullerene molecules. It is desirable to assemble aligned SWNTs into macroscopic structures because the common alignment of the SWNTs in such a structure makes it possible to exploit, on a macroscopic scale, the unique mechanical, chemical, and electrical properties that individual oriented SWNTs exhibit at the molecular level. Because of their small size and high electrical conductivity, carbon nanotubes, and especially SWNTs, are useful for making electrical connectors in integrated circuits. Carbon nanotubes can be used as antennas at optical frequencies, and as probes in scanning tunneling microscopes, atomic-force microscopes, and the like. Carbon nanotubes can be used with or instead of carbon black in tires. Carbon nanotubes are useful as supports for catalysts. Ropes of SWNTs are metallic and, as such, are potentially useful in some applications in which electrical conductors are needed - for example, they could be used as additives in formulating electrically conductive paints. Finally, macroscopic assemblies of aligned SWNTs can serve as templates for the growth of more and larger structures of the same type. The great variety of tubular fullerene molecules and of the structures that could be formed by assembling them in various ways precludes a complete description of the present method within the limits of this article. It must suffice to present a typical example of the use of one of many possible variants of the method to form a membrane comprising SWNTs aligned substantially parallel to each other in the membrane plane. The apparatus used in this variant

  8. EDITORIAL: Optical orientation Optical orientation

    NASA Astrophysics Data System (ADS)

    SAME ADDRESS *, Yuri; Landwehr, Gottfried

    2008-11-01

    priority of the discovery in the literature, which was partly caused by the existence of the Iron Curtain. I had already enjoyed contact with Boris in the 1980s when the two volumes of Landau Level Spectroscopy were being prepared [2]. He was one of the pioneers of magneto-optics in semiconductors. In the 1950s the band structure of germanium and silicon was investigated by magneto-optical methods, mainly in the United States. No excitonic effects were observed and the band structure parameters were determined without taking account of excitons. However, working with cuprous oxide, which is a direct semiconductor with a relative large energy gap, Zakharchenya and his co-worker Seysan showed that in order to obtain correct band structure parameters, it is necessary to take excitons into account [3]. About 1970 Boris started work on optical orientation. Early work by Hanle in Germany in the 1920s on the depolarization of luminescence in mercury vapour by a transverse magnetic field was not appreciated for a long time. Only in the late 1940s did Kastler and co-workers in Paris begin a systematic study of optical pumping, which led to the award of a Nobel prize. The ideas of optical pumping were first applied by Georges Lampel to solid state physics in 1968. He demonstrated optical orientation of free carriers in silicon. The detection method was nuclear magnetic resonance; optically oriented free electrons dynamically polarized the 29Si nuclei of the host lattice. The first optical detection of spin orientation was demonstrated by with the III-V semiconductor GaSb by Parsons. Due to the various interaction mechanisms of spins with their environment, the effects occurring in semiconductors are naturally more complex than those in atoms. Optical detection is now the preferred method to detect spin alignment in semiconductors. The orientation of spins in crystals pumped with circularly polarized light is deduced from the degree of circular polarization of the recombination

  9. Growth and Properties of Self-Aligned MgO Nanowires

    NASA Astrophysics Data System (ADS)

    Cimpoiasu, Elena; Klie, Robert F.; Munden, Ryan A.; Reed, Mark A.

    2008-03-01

    A simple VLS route was used to produce self-aligned MgO nanowires on both polished crystalline (c-axis sapphire) and ceramic (alumina) surfaces. Growth on alumina produces vertically-aligned, very thin nanowires, indicating enhanced growth at the liquid-solid interface. Growth on polished sapphire results in faceted MgO nanowires which are perpendicular to the r-plane of sapphire and show evidence of competing vapor-solid growth mechanism. The difference in the morphology and structure of the nanowires grown using the two different substrates clearly illustrates the affect of substrate on the growth process. This work was partially supported by DARPA, by the Department of Homeland Security, and by the National Science Foundation.

  10. PDV Probe Alignment Technique

    SciTech Connect

    Whitworth, T L; May, C M; Strand, O T

    2007-10-26

    This alignment technique was developed while performing heterodyne velocimetry measurements at LLNL. There are a few minor items needed, such as a white card with aperture in center, visible alignment laser, IR back reflection meter, and a microscope to view the bridge surface. The work was performed on KCP flyers that were 6 and 8 mils wide. The probes used were Oz Optics manufactured with focal distances of 42mm and 26mm. Both probes provide a spot size of approximately 80?m at 1550nm. The 42mm probes were specified to provide an internal back reflection of -35 to -40dB, and the probe back reflections were measured to be -37dB and -33dB. The 26mm probes were specified as -30dB and both measured -30.5dB. The probe is initially aligned normal to the flyer/bridge surface. This provides a very high return signal, up to -2dB, due to the bridge reflectivity. A white card with a hole in the center as an aperture can be used to check the reflected beam position relative to the probe and launch beam, and the alignment laser spot centered on the bridge, see Figure 1 and Figure 2. The IR back reflection meter is used to measure the dB return from the probe and surface, and a white card or similar object is inserted between the probe and surface to block surface reflection. It may take several iterations between the visible alignment laser and the IR back reflection meter to complete this alignment procedure. Once aligned normal to the surface, the probe should be tilted to position the visible alignment beam as shown in Figure 3, and the flyer should be translated in the X and Y axis to reposition the alignment beam onto the flyer as shown in Figure 4. This tilting of the probe minimizes the amount of light from the bridge reflection into the fiber within the probe while maintaining the alignment as near normal to the flyer surface as possible. When the back reflection is measured after the tilt adjustment, the level should be about -3dB to -6dB higher than the probes

  11. Crystal-oriented tungsten-bronze type ceramics prepared by a rotating magnetic field

    NASA Astrophysics Data System (ADS)

    Tanaka, S.; Doshida, Y.; Shimizu, H.; Furushima, R.; Uematsu, K.

    2011-03-01

    Forming and sintering of c-axis-oriented Sr2NaNb5O15 (SNN) ceramics were examined. Particle-oriented SNN was fabricated by using a rotating high magnetic field and subsequent sintering without magnetic field. SNN ceramics are tungsten-bronze-type ferroelectric materials with a tetragonal crystal system. The diamagnetic susceptibilities of the c-axis are smaller than that of the a- and b-axis (χc < χa,b < 0). SNN powder was prepared by conventional solid-state reaction. The synthesized powder was mixed with distilled water and a dispersant by using ball milling to give a slurry with solid loading of 30 vol%. The slurry was poured into a plastic mold and this was placed in a 10Tesla magnetic field in a superconducting magnet. The mold was rotated at 30 rpm while the slurry dried at room temperature. The resulting powder compact with a columnar shape was heated at 5 K/min to 1473 K, held for 6 h, and then heated at 1525 K for 2 h to prevent exaggerated grain growth. XRD patterns showed that c-axis-oriented SNN polycrystalline ceramics were produced in the presence of the rotating magnetic field. In XRD patterns viewed from the top surface of the sintered specimens, peaks from the c-planes of the crystal, such as 001 and 002, were very strong. Diffraction peaks which were very strong in the ceramics, such as 320 and 410, were absent in the specimen. Oriented microstructure was developed well by sintering. Grain-growth along to c-axis was observed in the SNN ceramics heated at 1525 K.

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

    ERIC Educational Resources Information Center

    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…

  13. Effects of the crystallographic orientation of Sn on the electromigration of Cu/Sn-Ag-Cu/Cu ball joints

    SciTech Connect

    Lee, Kiju; Kim, Keun-Soo; Tsukada, Yutaka; Suganuma, Katsuaki; Yamanaka, Kimihiro; Kuritani, Soichi; Ueshima, Minoru

    2011-11-17

    Electromigration behavior and fast circuit failure with respect to crystallographic orientation of Sn grains were examined. The test vehicle was Cu/Sn-3.0 wt% Ag-0.5 wt% Cu/Cu ball joints, and the applied current density was 15 kA/cm2 at 160 °C. The experimental results indicate that most of the solder bumps show different microstructural changes with respect to the crystallographic orientation of Sn grains. Fast failure of the bump occurred due to the dissolution of the Cu circuit on the cathode side caused by the fast interstitial diffusion of Cu atoms along the c-axis of the Sn grains when the c-axis was parallel to the electron flow. Slight microstructural changes were observed when the c-axis was perpendicular to the electron flow. In addition, Cu6Sn5 intermetallic compound (IMC) was formed along the direction of the c-axis of the Sn grains instead of the direction of electron flow in all solder ball joints.

  14. Magnetic alignment of block copolymer microdomains by intrinsic chain anisotropy

    SciTech Connect

    Rokhlenko, Yekaterina; Yager, Kevin G.; Gopinadhan, Manesh; Osuji, Chinedum O.; Zhang, Kai; O'Hern, Corey S.; Larson, Steven R.; Gopalan, Padma; Majewski, Pawel W.

    2015-12-18

    We examine the role of intrinsic chain susceptibility anisotropy in magnetic field directed self-assembly of a block copolymer using in situ x-ray scattering. Alignment of a lamellar mesophase is observed on cooling across the disorder-order transition with the resulting orientational order inversely proportional to the cooling rate. We discuss the origin of the susceptibility anisotropy, Δχ, that drives alignment and calculate its magnitude using coarse-grained molecular dynamics to sample conformations of surface-tethered chains, finding Δχ ≈ 2×10–8. From field-dependent scattering data, we estimate that grains of ≈ 1.2 μm are present during alignment. Furthermore, these results demonstrate that intrinsic anisotropy is sufficient to support strong field-induced mesophase alignment and suggest a versatile strategy for field control of orientational order in block copolymers.

  15. Magnetic alignment of block copolymer microdomains by intrinsic chain anisotropy

    DOE PAGES

    Rokhlenko, Yekaterina; Yager, Kevin G.; Gopinadhan, Manesh; Osuji, Chinedum O.; Zhang, Kai; O'Hern, Corey S.; Larson, Steven R.; Gopalan, Padma; Majewski, Pawel W.

    2015-12-18

    We examine the role of intrinsic chain susceptibility anisotropy in magnetic field directed self-assembly of a block copolymer using in situ x-ray scattering. Alignment of a lamellar mesophase is observed on cooling across the disorder-order transition with the resulting orientational order inversely proportional to the cooling rate. We discuss the origin of the susceptibility anisotropy, Δχ, that drives alignment and calculate its magnitude using coarse-grained molecular dynamics to sample conformations of surface-tethered chains, finding Δχ ≈ 2×10–8. From field-dependent scattering data, we estimate that grains of ≈ 1.2 μm are present during alignment. Furthermore, these results demonstrate that intrinsic anisotropymore » is sufficient to support strong field-induced mesophase alignment and suggest a versatile strategy for field control of orientational order in block copolymers.« less

  16. Magnetic Alignment of Block Copolymer Microdomains by Intrinsic Chain Anisotropy

    NASA Astrophysics Data System (ADS)

    Rokhlenko, Yekaterina; Gopinadhan, Manesh; Osuji, Chinedum O.; Zhang, Kai; O'Hern, Corey S.; Larson, Steven R.; Gopalan, Padma; Majewski, Paweł W.; Yager, Kevin G.

    2015-12-01

    We examine the role of intrinsic chain susceptibility anisotropy in magnetic field directed self-assembly of a block copolymer using in situ x-ray scattering. Alignment of a lamellar mesophase is observed on cooling across the disorder-order transition with the resulting orientational order inversely proportional to the cooling rate. We discuss the origin of the susceptibility anisotropy, Δ χ , that drives alignment and calculate its magnitude using coarse-grained molecular dynamics to sample conformations of surface-tethered chains, finding Δ χ ≈2 ×1 0-8. From field-dependent scattering data, we estimate that grains of ≈1.2 μ m are present during alignment. These results demonstrate that intrinsic anisotropy is sufficient to support strong field-induced mesophase alignment and suggest a versatile strategy for field control of orientational order in block copolymers.

  17. Perceptual grouping in Gabor lattices: proximity and alignment.

    PubMed

    Claessens, Peter M; Wagemans, Johan

    2005-11-01

    We propose the Gabor lattice as a new stimulus designed to deal with multiple organizations in perceptual grouping, allowing both comparison between psychophysical data and neural findings and a systematic investigation of grouping based on several low-level characteristics and their interactions. A Gabor lattice is a geometric lattice with Gabor patches, evoking a multistable global orientation percept. Visual grouping in Gabor lattices with elements aligned in a global orientation was compared with grouping of nonaligned Gabor patches and of Gaussian blobs. The effect sizes of proximity and alignment were estimated in logistic regression analyses. The results confirmed the importance of proximity and local element alignment as factors in dynamic grouping. We also found a small but consistent enhancement of grouping along the global vector orthogonal to the local patch orientations. In light of these results, we further motivate the relevance of these stimuli and the associated experimental paradigm.

  18. Alignment of cD-galaxies with their surroundings

    NASA Technical Reports Server (NTRS)

    Vankampen, Eelco; Rhee, George

    1990-01-01

    For a sample of 122 rich Abell clusters the authors find a strong correlation of the position angle (orientation) of the first-ranked galaxy and its parent cluster. This alignment effect is strongest for cD-galaxies. Formation scenarios for cD galaxies, like the merging scenario, must produce such a strong alignment effect. The authors show some N-body simulations done for this purpose.

  19. Alignment of cD-galaxies with their surroundings

    NASA Astrophysics Data System (ADS)

    van Kampen, Eelco; Rhee, George

    1990-11-01

    For a sample of 122 rich Abell clusters the authors find a strong correlation of the position angle (orientation) of the first-ranked galaxy and its parent cluster. This alignment effect is strongest for cD-galaxies. Formation scenarios for cD galaxies, like the merging scenario, must produce such a strong alignment effect. The authors show some N-body simulations done for this purpose.

  20. Two-center minima in harmonic spectra from aligned polar molecules

    SciTech Connect

    Etches, Adam; Gaarde, Mette B.; Madsen, Lars Bojer

    2011-08-15

    We extend a model of two-center interference to include the superposition of opposite orientations in aligned polar molecules. We show that the position of the minimum in the harmonic spectrum from both aligned and oriented CO depends strongly on the relative recombination strength at different atoms, not just the relative phase. We reinterpret the minimum in aligned CO as an interference between opposite orientations, and obtain good agreement with numerical calculations. Inclusion of the first-order Stark effect shifts the position of the interference minimum in aligned CO even though aligned molecules do not posses total permanent dipoles. We explain the shift in terms of the phase that the electron of oriented CO accumulates due to the Stark effect.

  1. Cluster Position Angle Alignments in the CLASH Survey

    NASA Astrophysics Data System (ADS)

    McIntosh, Melissa; de Propris, Roberto; West, Michael

    2016-01-01

    There exists strong evidence for nearby brightest cluster galaxies (BCGs) to exhibit preferential orientation with respect to their surroundings. Primarily, we see these bright member galaxies aligning themselves with the cluster's principal axis. We have examined the orientations of the 25 CLASH Survey galaxy clusters to see whether this tendency for BCGs to share the same major axis orientation as their host cluster extends to galaxy clusters at redshifts up to 0.9. We find evidence of preferential orientations existing in clusters at these redshifts. The significance of this finding for theories of the formation of clusters are discussed. Supported by NSF Grant #1358980 and the MA Space Grant Consortium.

  2. Optics Alignment Panel

    NASA Technical Reports Server (NTRS)

    Schroeder, Daniel J.

    1992-01-01

    The Optics Alignment Panel (OAP) was commissioned by the HST Science Working Group to determine the optimum alignment of the OTA optics. The goal was to find the position of the secondary mirror (SM) for which there is no coma or astigmatism in the camera images due to misaligned optics, either tilt or decenter. The despace position was reviewed of the SM and the optimum focus was sought. The results of these efforts are as follows: (1) the best estimate of the aligned position of the SM in the notation of HDOS is (DZ,DY,TZ,TY) = (+248 microns, +8 microns, +53 arcsec, -79 arcsec), and (2) the best focus, defined to be that despace which maximizes the fractional energy at 486 nm in a 0.1 arcsec radius of a stellar image, is 12.2 mm beyond paraxial focus. The data leading to these conclusions, and the estimated uncertainties in the final results, are presented.

  3. Barrel alignment fixture

    NASA Astrophysics Data System (ADS)

    Sheeley, J. D.

    1981-04-01

    Fabrication of slapper type detonator cables requires bonding of a thin barrel over a bridge. Location of the barrel hole with respect to the bridge is critical: the barrel hole must be centered over the bridge uniform spacing on each side. An alignment fixture which permits rapid adjustment of the barrel position with respect to the bridge is described. The barrel is manipulated by pincer-type fingers which are mounted on a small x-y table equipped with micrometer adjustments. Barrel positioning, performed under a binocular microscopy, is rapid and accurate. After alignment, the microscope is moved out of position and an infrared (IR) heat source is aimed at the barrel. A 5-second pulse of infrared heat flows the adhesive under the barrel and bonds it to the cable. Sapphire and Fotoform glass barrels were bonded successfully with the alignment fixture.

  4. Magnetically aligned supramolecular hydrogels.

    PubMed

    Wallace, Matthew; Cardoso, Andre Zamith; Frith, William J; Iggo, Jonathan A; Adams, Dave J

    2014-12-01

    The magnetic-field-induced alignment of the fibrillar structures present in an aqueous solution of a dipeptide gelator, and the subsequent retention of this alignment upon transformation to a hydrogel upon the addition of CaCl2 or upon a reduction in solution pH is reported. Utilising the switchable nature of the magnetic field coupled with the slow diffusion of CaCl2 , it is possible to precisely control the extent of anisotropy across a hydrogel, something that is generally very difficult to do using alternative methods. The approach is readily extended to other compounds that form viscous solutions at high pH. It is expected that this work will greatly expand the utility of such low-molecular-weight gelators (LMWG) in areas where alignment is key. PMID:25345918

  5. MUSE optical alignment procedure

    NASA Astrophysics Data System (ADS)

    Laurent, Florence; Renault, Edgard; Loupias, Magali; Kosmalski, Johan; Anwand, Heiko; Bacon, Roland; Boudon, Didier; Caillier, Patrick; Daguisé, Eric; Dubois, Jean-Pierre; Dupuy, Christophe; Kelz, Andreas; Lizon, Jean-Louis; Nicklas, Harald; Parès, Laurent; Remillieux, Alban; Seifert, Walter; Valentin, Hervé; Xu, Wenli

    2012-09-01

    MUSE (Multi Unit Spectroscopic Explorer) is a second generation VLT integral field spectrograph (1x1arcmin² Field of View) developed for the European Southern Observatory (ESO), operating in the visible wavelength range (0.465-0.93 μm). A consortium of seven institutes is currently assembling and testing MUSE in the Integration Hall of the Observatoire de Lyon for the Preliminary Acceptance in Europe, scheduled for 2013. MUSE is composed of several subsystems which are under the responsibility of each institute. The Fore Optics derotates and anamorphoses the image at the focal plane. A Splitting and Relay Optics feed the 24 identical Integral Field Units (IFU), that are mounted within a large monolithic instrument mechanical structure. Each IFU incorporates an image slicer, a fully refractive spectrograph with VPH-grating and a detector system connected to a global vacuum and cryogenic system. During 2011, all MUSE subsystems were integrated, aligned and tested independently in each institute. After validations, the systems were shipped to the P.I. institute at Lyon and were assembled in the Integration Hall This paper describes the end-to-end optical alignment procedure of the MUSE instrument. The design strategy, mixing an optical alignment by manufacturing (plug and play approach) and few adjustments on key components, is presented. We depict the alignment method for identifying the optical axis using several references located in pupil and image planes. All tools required to perform the global alignment between each subsystem are described. The success of this alignment approach is demonstrated by the good results for the MUSE image quality. MUSE commissioning at the VLT (Very Large Telescope) is planned for 2013.

  6. Alignment of atmospheric mineral dust due to electric field

    NASA Astrophysics Data System (ADS)

    Ulanowski, Z.; Bailey, J.; Lucas, P. W.; Hough, J. H.; Hirst, E.

    2007-12-01

    Optical polarimetry observations on La Palma, Canary Islands, during a Saharan dust episode show dichroic extinction indicating the presence of vertically aligned particles in the atmosphere. Modelling of the extinction together with particle orientation indicates that the alignment could have been due to an electric field of the order of 2 kV/m. Two alternative mechanisms for the origin of the field are examined: the effect of reduced atmospheric conductivity and charging of the dust layer, the latter effect being a more likely candidate. It is concluded that partial alignment may be a common feature of Saharan dust layers. The modelling indicates that the alignment can significantly alter dust optical depth. This "Venetian blind effect" may have decreased optical thickness in the vertical direction by as much as 10% for the case reported here. It is also possible that the alignment and the electric field modify dust transport.

  7. Understanding and overcoming shear alignment of fibers during extrusion.

    PubMed

    Martin, Joshua J; Riederer, Michael S; Krebs, Melissa D; Erb, Randall M

    2015-01-14

    Fiber alignment is the defining architectural characteristic of discontinuous fiber composites and is dictated by shear-dominated processing techniques including flow-injection molding, tape-casting, and mold-casting. However, recent colloidal assembly techniques have started to employ additional forces in fiber suspensions that have the potential to change the energy landscape of the shear-dominated alignment in conditions of flow. In this paper, we develop an energetics model to characterize the shear-alignment of rigid fibers under different flow conditions in the presence of magnetic colloidal alignment forces. We find that these colloidal forces can be sufficient to manipulate the energetic landscape and obtain tunable fiber alignment during flow within even small geometries, such as capillary flow. In most conditions, these colloidal forces work to freeze the fiber orientation during flow and prevent the structure disrupting phenomenon of Jeffrey's orbits that has been accepted to rule fiber suspensions under simple shear flow. PMID:25408494

  8. PILOT optical alignment

    NASA Astrophysics Data System (ADS)

    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.

  9. Cooperative liquid-crystal alignment generated by overlaid topography

    NASA Astrophysics Data System (ADS)

    Yi, Youngwoo; Maclennan, Joseph E.; Clark, Noel A.

    2011-05-01

    Nematic and smectic liquid crystals were introduced into μm-scale gaps between plates coated with polymer films nanoimprinted with parallel arrays of rectangular channels. Overlaying the channels on the two plates close enough at a slight angle produces a mosaic of alternating planar and homeotropic alignments and hybrid alignment, showing that complex liquid-crystal orientation patterns can be achieved by combining two simple topographic patterns. These alignment patterns are attributed to spatial variation of surface roughness and 3D topographic structure created by a sufficient proximity of the two patterns.

  10. Cooperative liquid-crystal alignment generated by overlaid topography.

    PubMed

    Yi, Youngwoo; Maclennan, Joseph E; Clark, Noel A

    2011-05-01

    Nematic and smectic liquid crystals were introduced into μm-scale gaps between plates coated with polymer films nanoimprinted with parallel arrays of rectangular channels. Overlaying the channels on the two plates close enough at a slight angle produces a mosaic of alternating planar and homeotropic alignments and hybrid alignment, showing that complex liquid-crystal orientation patterns can be achieved by combining two simple topographic patterns. These alignment patterns are attributed to spatial variation of surface roughness and 3D topographic structure created by a sufficient proximity of the two patterns. PMID:21728557

  11. Alignments of the Dominant Galaxies in Poor Clusters

    NASA Astrophysics Data System (ADS)

    Fuller, Todd M.; West, Michael J.; Bridges, Terry J.

    1999-07-01

    We have examined the orientations of brightest cluster galaxies (BCGs) in poor MKW (Morgan, Kayser, and White) and AWM (Albert, White, and Morgan) clusters and find that, like their counterparts in richer Abell clusters, poor cluster BCGs exhibit a strong propensity to be aligned with the principal axes of their host clusters as well as the surrounding distribution of nearby (<=20 h-1 Mpc) Abell clusters. The processes responsible for dominant galaxy alignments are therefore independent of cluster richness. We argue that these alignments most likely arise from anisotropic infall of material into clusters along large-scale filaments.

  12. Nanodrawing of Aligned Single Carbon Nanotubes with a Nanopen.

    PubMed

    Yeshua, Talia; Lehmann, Christian; Hübner, Uwe; Azoubel, Suzanna; Magdassi, Shlomo; Campbell, Eleanor E B; Reich, Stephanie; Lewis, Aaron

    2016-03-01

    Single-walled carbon nanotubes (SWCNTs) are considered pivotal components for molecular electronics. Techniques for SWCNT lithography today lack simplicity, flexibility, and speed of direct, oriented deposition at specific target locations. In this paper SWCNTs are directly drawn and placed with chemical identification and demonstrated orientation using fountain pen nanolithography (FPN) under ambient conditions. Placement across specific electrical contacts with such alignment is demonstrated and characterized. The fundamental basis of the drawing process with alignment has potential applications for other related systems such as inorganic nanotubes, polymers, and biological molecules.

  13. Alignment of gold nanorods by angular photothermal depletion

    SciTech Connect

    Taylor, Adam B.; Chow, Timothy T. Y.; Chon, James W. M.

    2014-02-24

    In this paper, we demonstrate that a high degree of alignment can be imposed upon randomly oriented gold nanorod films by angular photothermal depletion with linearly polarized laser irradiation. The photothermal reshaping of gold nanorods is observed to follow quadratic melting model rather than the threshold melting model, which distorts the angular and spectral hole created on 2D distribution map of nanorods to be an open crater shape. We have accounted these observations to the alignment procedures and demonstrated good agreement between experiment and simulations. The use of multiple laser depletion wavelengths allowed alignment criteria over a large range of aspect ratios, achieving 80% of the rods in the target angular range. We extend the technique to demonstrate post-alignment in a multilayer of randomly oriented gold nanorod films, with arbitrary control of alignment shown across the layers. Photothermal angular depletion alignment of gold nanorods is a simple, promising post-alignment method for creating future 3D or multilayer plasmonic nanorod based devices and structures.

  14. Magnetic Field Measurement with Ground State Alignment

    NASA Astrophysics Data System (ADS)

    Yan, Huirong; Lazarian, A.

    Observational studies of magnetic fields are crucial. We introduce a process "ground state alignment" as a new way to determine the magnetic field direction in diffuse medium. The alignment is due to anisotropic radiation impinging on the atom/ion. The consequence of the process is the polarization of spectral lines resulting from scattering and absorption from aligned atomic/ionic species with fine or hyperfine structure. The magnetic field induces precession and realign the atom/ion and therefore the polarization of the emitted or absorbed radiation reflects the direction of the magnetic field. The atoms get aligned at their low levels and, as the life-time of the atoms/ions we deal with is long, the alignment induced by anisotropic radiation is susceptible to extremely weak magnetic fields (1 G ≳ B ≳ 10^{-15} G). In fact, the effects of atomic/ionic alignment were studied in the laboratory decades ago, mostly in relation to the maser research. Recently, the atomic effect has been already detected in observations from circumstellar medium and this is a harbinger of future extensive magnetic field studies. A unique feature of the atomic realignment is that they can reveal the 3D orientation of magnetic field. In this chapter, we shall review the basic physical processes involved in atomic realignment. We shall also discuss its applications to interplanetary, circumstellar and interstellar magnetic fields. In addition, our research reveals that the polarization of the radiation arising from the transitions between fine and hyperfine states of the ground level can provide a unique diagnostics of magnetic fields in the Epoch of Reionization.

  15. On the absolute alignment of GONG images

    NASA Astrophysics Data System (ADS)

    Toner, C. G.

    2001-01-01

    In order to combine data from the six instruments in the GONG network the alignment of all of the images must be known to a fairly high precision (~0°.1 for GONG Classic and ~0°.01 for GONG+). The relative orientation is obtained using the angular cross-correlation method described by (Toner & Harvey, 1998). To obtain the absolute orientation the Project periodically records a day of drift scans, where the image of the Sun is allowed to drift across the CCD repeatedly throughout the day. These data are then analyzed to deduce the direction of Terrestrial East-West as a function of hour angle (i.e., time) for that instrument. The transit of Mercury on Nov. 15, 1999, which was recorded by three of the GONG instruments, provided an independent check on the current alignment procedures. Here we present a comparison of the alignment of GONG images as deduced from both drift scans and the Mercury transit for two GONG sites: Tucson (GONG+ camera) and Mauna Loa (GONG Classic camera). The agreement is within ~0°.01 for both cameras, however, the scatter is substantially larger for GONG Classic: ~0°.03 compared to ~0°.01 for GONG+.

  16. Curriculum Alignment: Establishing Coherence

    ERIC Educational Resources Information Center

    Gagné, Philippe; Dumont, Laurence; Brunet, Sabine; Boucher, Geneviève

    2013-01-01

    In this paper, we present a step-by-step guide to implement a curricular alignment project, directed at professional development and student support, and developed in a higher education French as a second language department. We outline best practices and preliminary results from our experience and provide ways to adapt our experience to other…

  17. Optically Aligned Drill Press

    NASA Technical Reports Server (NTRS)

    Adderholdt, Bruce M.

    1994-01-01

    Precise drill press equipped with rotary-indexing microscope. Microscope and drill exchange places when turret rotated. Microscope axis first aligned over future hole, then rotated out of way so drill axis assumes its precise position. New procedure takes less time to locate drilling positions and produces more accurate results. Apparatus adapted to such other machine tools as milling and measuring machines.

  18. Aligning brains and minds

    PubMed Central

    Tong, Frank

    2012-01-01

    In this issue of Neuron, Haxby and colleagues describe a new method for aligning functional brain activity patterns across participants. Their study demonstrates that objects are similarly represented across different brains, allowing for reliable classification of one person’s brain activity based on another’s. PMID:22017984

  19. Aligned-or Not?

    ERIC Educational Resources Information Center

    Roseman, Jo Ellen; Koppal, Mary

    2015-01-01

    When state leaders and national partners in the development of the Next Generation Science Standards met to consider implementation strategies, states and school districts wanted to know which materials were aligned to the new standards. The answer from the developers was short but not sweet: You won't find much now, and it's going to…

  20. Controlling laser emission by selecting crystal orientation

    NASA Astrophysics Data System (ADS)

    Chen, Lijuan; Han, Shujuan; Wang, Zhengping; Wang, Jiyang; Zhang, Huanjin; Yu, Haohai; Han, Shuo; Xu, Xinguang

    2013-01-01

    Based on the anisotropy of laser crystal, we demonstrate a method of adjusting laser emission by selecting crystal orientation. When the light propagating direction varies from a to c axis of Nd:LiGd(MoO4)2 crystal, emission wavelength exhibits a sensitive change of 1061 nm → 1061/1062 + 1068 nm → 1068 nm. The experimental discipline is well explained by a theoretical study of simulating on the spatial distribution of stimulated emission cross-section. This letter manifests that the laser property along non-principal-axis direction is also valuable for research and application, which breaks through the traditional custom of using laser materials processed along principal-axis.

  1. Bokeh mirror alignment for Cherenkov telescopes

    NASA Astrophysics Data System (ADS)

    Ahnen, M. L.; Baack, D.; Balbo, M.; Bergmann, M.; Biland, A.; Blank, M.; Bretz, T.; Bruegge, K. A.; Buss, J.; Domke, M.; Dorner, D.; Einecke, S.; Hempfling, C.; Hildebrand, D.; Hughes, G.; Lustermann, W.; Mannheim, K.; Mueller, S. A.; Neise, D.; Neronov, A.; Noethe, M.; Overkemping, A.-K.; Paravac, A.; Pauss, F.; Rhode, W.; Shukla, A.; Temme, F.; Thaele, J.; Toscano, S.; Vogler, P.; Walter, R.; Wilbert, A.

    2016-09-01

    Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures and high image intensities to map the faint Cherenkov light emitted from cosmic ray air showers onto their image sensors. Segmented reflectors fulfill these needs, and composed from mass production mirror facets they are inexpensive and lightweight. However, as the overall image is a superposition of the individual facet images, alignment remains a challenge. Here we present a simple, yet extendable method, to align a segmented reflector using its Bokeh. Bokeh alig nment does not need a star or good weather nights but can be done even during daytime. Bokeh alignment optimizes the facet orientations by comparing the segmented reflectors Bokeh to a predefined template. The optimal Bokeh template is highly constricted by the reflector's aperture and is easy accessible. The Bokeh is observed using the out of focus image of a near by point like light source in a distance of about 10 focal lengths. We introduce Bokeh alignment on segmented reflectors and demonstrate it on the First Geiger-mode Avalanche Cherenkov Telescope (FACT) on La Palma, Spain.

  2. Nanofiber alignment of a small diameter elastic electrospun scaffold

    NASA Astrophysics Data System (ADS)

    Patel, Jignesh

    Cardiovascular disease is the leading cause of death in western countries with coronary heart disease making up 50% of these deaths. As a treatment option, tissue engineered grafts have great potential. Elastic scaffolds that mimic arterial extracellular matrix (ECM) may hold the key to creating viable vascular grafts. Electrospinning is a widely used scaffold fabrication technique to engineer tubular scaffolds. In this study, we investigated how the collector rotation speed altered the nanofiber alignment which may improve mechanical characteristics making the scaffold more suitable for arterial grafts. The scaffold was fabricated from a blend of PCL/Elastin. 2D Fast Fourier Transform (FFT) image processing tool and MatLab were used to quantitatively analyze nanofiber orientation at different collector speeds (13500 to 15500 rpm). Both Image J and MatLab showed graphical peaks indicating predominant fiber orientation angles. A collector speed of 15000 rpm was found to produce the best nanofiber alignment with narrow peaks at 90 and 270 degrees, and a relative amplitude of 200. This indicates a narrow distribution of circumferentially aligned nanofibers. Collector speeds below and above 15000 rpm caused a decrease in fiber alignment with a broader orientation distribution. Uniformity of fiber diameter was also measured. Of 600 measures from the 15000 rpm scaffolds, the fiber diameter range from 500 nm to 899 nm was most prevalent. This diameter range was slightly larger than native ECM which ranges from 50 nm to 500 nm. The second most prevalent diameter range had an average of 404 nm which is within the diameter range of collagen. This study concluded that with proper electrospinning technique and collector speed, it is possible to fabricate highly aligned small diameter elastic scaffolds. Image J 2D FFT results confirmed MatLab findings for the analyses of circumferentially aligned nanofibers. In addition, MatLab analyses simplified the FFT orientation data

  3. Internal Alignment of the SLD Vertex Detector

    SciTech Connect

    Jackson, D.J.; Wickens, F.J.; Su, D.; /SLAC

    2007-12-03

    The tracking resolution and vertex finding capabilities of the SLD experiment depended upon a precise knowledge of the location and orientation of the elements of the SLD pixel vertex detector (VXD3) in 3D space. At the heart of the procedure described here to align the 96 CCDs is the matrix inversion technique of singular value decomposition (SVD). This tool was employed to unfold the detector geometry corrections from the track data in the VXD3. The algorithm was adapted to perform an optimal {chi}{sup 2} minimization by careful treatment of the track hit residual measurement errors. The tracking resolution obtained with the aligned geometry achieved the design performance. Comments are given on how this method could be used for other trackers.

  4. MUSE alignment onto VLT

    NASA Astrophysics Data System (ADS)

    Laurent, Florence; Renault, Edgard; Boudon, Didier; Caillier, Patrick; Daguisé, Eric; Dupuy, Christophe; Jarno, Aurélien; Lizon, Jean-Louis; Migniau, Jean-Emmanuel; Nicklas, Harald; Piqueras, Laure

    2014-07-01

    MUSE (Multi Unit Spectroscopic Explorer) is a second generation Very Large Telescope (VLT) integral field spectrograph developed for the European Southern Observatory (ESO). It combines a 1' x 1' field of view sampled at 0.2 arcsec for its Wide Field Mode (WFM) and a 7.5"x7.5" field of view for its Narrow Field Mode (NFM). Both modes will operate with the improved spatial resolution provided by GALACSI (Ground Atmospheric Layer Adaptive Optics for Spectroscopic Imaging), that will use the VLT deformable secondary mirror and 4 Laser Guide Stars (LGS) foreseen in 2015. MUSE operates in the visible wavelength range (0.465-0.93 μm). A consortium of seven institutes is currently commissioning MUSE in the Very Large Telescope for the Preliminary Acceptance in Chile, scheduled for September, 2014. MUSE is composed of several subsystems which are under the responsibility of each institute. The Fore Optics derotates and anamorphoses the image at the focal plane. A Splitting and Relay Optics feed the 24 identical Integral Field Units (IFU), that are mounted within a large monolithic structure. Each IFU incorporates an image slicer, a fully refractive spectrograph with VPH-grating and a detector system connected to a global vacuum and cryogenic system. During 2012 and 2013, all MUSE subsystems were integrated, aligned and tested to the P.I. institute at Lyon. After successful PAE in September 2013, MUSE instrument was shipped to the Very Large Telescope in Chile where that was aligned and tested in ESO integration hall at Paranal. After, MUSE was directly transported, fully aligned and without any optomechanical dismounting, onto VLT telescope where the first light was overcame the 7th of February, 2014. This paper describes the alignment procedure of the whole MUSE instrument with respect to the Very Large Telescope (VLT). It describes how 6 tons could be move with accuracy better than 0.025mm and less than 0.25 arcmin in order to reach alignment requirements. The success

  5. Electric-Field-Induced Alignment of Block Copolymer/Nanoparticle Blends

    SciTech Connect

    Liedel, Clemens; Schindler, Kerstin; Pavan, Mariela J.; Lewin, Christian; Pester, Christian W; Ruppel, Markus A; Urban, Volker S; Shenhar, Roy; Boker, Alexander

    2013-01-01

    External electric fi elds readily align birefringent block-copolymer mesophases. In this study the effect of gold nanoparticles on the electric-fi eld-induced alignment of a lamellae-forming polystyrene- block -poly(2-vinylpyridine) copolymer is assessed. Nanoparticles are homogeneously dispersed in the styrenic phase and promote the quantitative alignment of lamellar domains by substantially lowering the critical field strength above which alignment proceeds. The results suggest that the electric-fi eldassisted alignment of nanostructured block copolymer/nanoparticle composites may offer a simple way to greatly mitigate structural and orientational defects of such fi lms under benign experimental conditions.

  6. Electric-field-induced alignment of block copolymer/nanoparticle blends.

    PubMed

    Liedel, Clemens; Schindler, Kerstin A; Pavan, Mariela J; Lewin, Christian; Pester, Christian W; Ruppel, Markus; Urban, Volker S; Shenhar, Roy; Böker, Alexander

    2013-10-11

    External electric fields readily align birefringent block-copolymer mesophases. In this study the effect of gold nanoparticles on the electric-field-induced alignment of a lamellae-forming polystyrene-block-poly(2-vinylpyridine) copolymer is assessed. Nanoparticles are homogeneously dispersed in the styrenic phase and promote the quantitative alignment of lamellar domains by substantially lowering the critical field strength above which alignment proceeds. The results suggest that the electric-field-assisted alignment of nanostructured block copolymer/nanoparticle composites may offer a simple way to greatly mitigate structural and orientational defects of such films under benign experimental conditions. PMID:23495246

  7. Whose Orientations?

    ERIC Educational Resources Information Center

    Gutoff, Joshua

    2010-01-01

    This article presents the author's response to Jon A. Levisohn's article entitled "A Menu of Orientations in the Teaching of Rabbinic Literature." While the "menu" Levisohn describes in his groundbreaking work on orientations to the teaching of rabbinic texts will almost certainly be refined over time, even as it stands this article should be of…

  8. Comparison and analysis of linear alignments from Landsat imagery of diverse geologic terrane

    SciTech Connect

    Frederking, R.L.; Allenbach, R.T.; Jackson, R.B.; Keefer, W.D.; Motamedi, A.R.; Von Der Heyde, W.S.; Wingo, R.D.

    1985-01-01

    Geometric alignments referred to as linears, linear features or lineaments are routinely observed on Landsat imagery. Alignments that cannot be accounted for by cultural, known geologic or other recognized sources are classed as speculative and of dubious geologic significance. These features may in fact be imaginary. Speculative alignments are however, important to exploration because of their frequent association with known hydrocarbon accumulations and/or areas of mineralization. Data pertaining to speculative linear alignments in diverse geologic terrane have been obtained. Alignment frequency rose diagrams are prepared for each area and statistical profiles are developed. Replication of linear alignments suggest that these features are real elements of the imagery and not imaginary lines. Observed orientation modal frequencies are consistent with alignment trends of known structural features in the different areas. Variation in spatial density of alignments appears to be related to lithologic factors.

  9. Near-surface alignment of polymers in rubbed films

    NASA Astrophysics Data System (ADS)

    Toney, Michael F.; Russell, Thomas P.; Logan, J. Anthony; Kikuchi, Hirotsugu; Sands, James M.; Kumar, Sanat K.

    1995-04-01

    RUBBED polymer films (generally polyimides) are used in flat-panel displays to control the alignment of liquid crystals in contact with the polymer1-8, a phenomenon first discovered by Maugin1 in 1911. Buffing the film with a cloth produces liquid-crystal alignment in the rubbing direction. Several mechanisms have been proposed to explain this effect. The generation of microgrooves or scratches on the polymer surface during rubbing has led to the suggestion that alignment is the result of long-range elastic effects induced by these surface features3-5. Others have suggested that the polymer chains near the surface are aligned during rubbing and that these then serve as templates for liquid-crystal alignment6-13. Other studies 10-l2 have implied that both mechanisms might be operative. Here we present X-ray scattering measurements which show unambiguously that rubbing a polyimide film causes near-surface alignment of the polymer molecules. For a film 200 nm thick, most of the polymer chains within a thin surface region (about 5 nm thick) are aligned in the rubbing direction; for a 6-nm film essentially all of the chains are aligned within 20° of the rubbing direction. This marked orientation of the near-surface chains at temperatures far below the bulk glass transition temperature shows that the mechanical properties of the near-surface region differ significantly from those of the bulk polymer.

  10. Connectivity independent protein-structure alignment: a hierarchical approach

    PubMed Central

    Kolbeck, Bjoern; May, Patrick; Schmidt-Goenner, Tobias; Steinke, Thomas; Knapp, Ernst-Walter

    2006-01-01

    Background Protein-structure alignment is a fundamental tool to study protein function, evolution and model building. In the last decade several methods for structure alignment were introduced, but most of them ignore that structurally similar proteins can share the same spatial arrangement of secondary structure elements (SSE) but differ in the underlying polypeptide chain connectivity (non-sequential SSE connectivity). Results We perform protein-structure alignment using a two-level hierarchical approach implemented in the program GANGSTA. On the first level, pair contacts and relative orientations between SSEs (i.e. α-helices and β-strands) are maximized with a genetic algorithm (GA). On the second level residue pair contacts from the best SSE alignments are optimized. We have tested the method on visually optimized structure alignments of protein pairs (pairwise mode) and for database scans. For a given protein structure, our method is able to detect significant structural similarity of functionally important folds with non-sequential SSE connectivity. The performance for structure alignments with strictly sequential SSE connectivity is comparable to that of other structure alignment methods. Conclusion As demonstrated for several applications, GANGSTA finds meaningful protein-structure alignments independent of the SSE connectivity. GANGSTA is able to detect structural similarity of protein folds that are assigned to different superfamilies but nevertheless possess similar structures and perform related functions, even if these proteins differ in SSE connectivity. PMID:17118190

  11. Inflation by alignment

    SciTech Connect

    Burgess, C.P.; Roest, Diederik

    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.

  12. Orbit IMU alignment: Error analysis

    NASA Technical Reports Server (NTRS)

    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.

  13. Nuclear reactor alignment plate configuration

    DOEpatents

    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.

  14. Alignment reference device

    DOEpatents

    Patton, Gail Y.; Torgerson, Darrel D.

    1987-01-01

    An alignment reference device provides a collimated laser beam that minimizes angular deviations therein. A laser beam source outputs the beam into a single mode optical fiber. The output end of the optical fiber acts as a source of radiant energy and is positioned at the focal point of a lens system where the focal point is positioned within the lens. The output beam reflects off a mirror back to the lens that produces a collimated beam.

  15. Shear-induced alignment and dynamics of elongated granular particles.

    PubMed

    Börzsönyi, Tamás; Szabó, Balázs; Wegner, Sandra; Harth, Kirsten; Török, János; Somfai, Ellák; Bien, Tomasz; Stannarius, Ralf

    2012-11-01

    The alignment, ordering, and rotation of elongated granular particles was studied in shear flow. The time evolution of the orientation of a large number of particles was monitored in laboratory experiments by particle tracking using optical imaging and x-ray computed tomography. The experiments were complemented by discrete element simulations. The particles develop an orientational order. In the steady state the time- and ensemble-averaged direction of the main axis of the particles encloses a small angle with the streamlines. This shear alignment angle is independent of the applied shear rate, and it decreases with increasing grain aspect ratio. At the grain level the steady state is characterized by a net rotation of the particles, as dictated by the shear flow. The distribution of particle rotational velocities was measured both in the steady state and also during the initial transients. The average rotation speed of particles with their long axis perpendicular to the shear alignment angle is larger, while shear aligned particles rotate slower. The ratio of this fast/slow rotation increases with particle aspect ratio. During the initial transient starting from an unaligned initial condition, particles having an orientation just beyond the shear alignment angle rotate opposite to the direction dictated by the shear flow.

  16. Dynamic Alignment at SLS

    SciTech Connect

    Ruland, Robert E.

    2003-04-23

    The relative alignment of components in the storage ring of the Swiss Light Source (SLS) is guaranteed by mechanical means. The magnets are rigidly fixed to 48 girders by means of alignment rails with tolerances of less than {+-}15 {micro}m. The bending magnets, supported by 3 point ball bearings, overlap adjacent girders and thus establish virtual train links between the girders, located near the bending magnet centres. Keeping the distortion of the storage ring geometry within a tolerance of {+-}100 {micro}m in order to guarantee sufficient dynamic apertures, requires continuous monitoring and correction of the girder locations. Two monitoring systems for the horizontal and the vertical direction will be installed to measure displacements of the train link between girders, which are due to ground settings and temperature effects: The hydrostatic levelling system (HLS) gives an absolute vertical reference, while the horizontal positioning system (HPS), which employs low cost linear encoders with sub-micron resolution, measures relative horizontal movements. The girder mover system based on five DC motors per girder allows a dynamic realignment of the storage ring within a working window of more than {+-}1 mm for girder translations and {+-}1 mrad for rotations. We will describe both monitoring systems (HLS and HPS) as well as the applied correction scheme based on the girder movers. We also show simulations indicating that beam based girder alignment takes care of most of the static closed orbit correction.

  17. Blocks and residual stresses in sapphire rods of different crystallographic orientations grown by the Stepanov method

    SciTech Connect

    Krymov, V. M. Nosov, Yu. G.; Bakholdin, S. I.; Maslov, V. N.; Shul’pina, I. L.

    2015-05-15

    The formation of blocks in shaped sapphire rods of two crystallographic orientations has been investigated. It is shown that, when growth occurs in the direction of the optical c axis, blocks are formed with a higher probability than in the case of growth in the a direction. A model of formation of blocks in rods of different orientations is proposed. The distribution of residual stresses over sapphire rod cross sections is measured by conoscopy. It is found that stresses increase from the middle of a rod to its periphery and reach 20 MPa.

  18. Hopi and Anasazi Alignments and Rock Art

    NASA Astrophysics Data System (ADS)

    Bates, Bryan C.

    The interaction of light and shadow on ancestral Puebloan rock art, or rock art demarcating sunrise/set horizon points that align with culturally significant dates, has long been assumed to be evidence of "intentional construct" for marking time or event by the native creator. However, anthropological rock art research requires the scientific control of cultural time, element orientation and placement, structure, and association with other rock art elements. The evaluation of five exemplars challenges the oft-held assumption that "if the interaction occurs, it therefore supports intentional construct" and thereby conveys meaning to the native culture.

  19. Alignment and alignment transition of bent core nematics

    NASA Astrophysics Data System (ADS)

    Elamain, Omaima; Hegde, Gurumurthy; Komitov, Lachezar

    2013-07-01

    We report on the alignment of nematics consisting of bimesogen bent core molecules of chlorine substituent of benzene derivative and their binary mixture with rod like nematics. It was found that the alignment layer made from polyimide material, which is usually used for promoting vertical (homeotropic) alignment of rod like nematics, promotes instead a planar alignment of the bent core nematic and its nematic mixtures. At higher concentration of the rod like nematic component in these mixtures, a temperature driven transition from vertical to planar alignment was found near the transition to isotropic phase.

  20. Polar cap arcs: Sun-aligned or cusp-aligned?

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Paxton, L. J.; Zhang, Qinghe; Xing, Zanyang

    2016-08-01

    Polar cap arcs are often called sun-aligned arcs. Satellite observations reveal that polar cap arcs join together at the cusp and are actually cusp aligned. Strong ionospheric plasma velocity shears, thus field aligned currents, were associated with polar arcs and they were likely caused by Kelvin-Helmholtz waves around the low-latitude magnetopause under a northward IMF Bz. The magnetic field lines around the magnetopause join together in the cusp region so are the field aligned currents and particle precipitation. This explains why polar arcs are cusp aligned.

  1. Nanofibril Alignment in Flow Focusing: Measurements and Calculations.

    PubMed

    Håkansson, Karl M O; Lundell, Fredrik; Prahl-Wittberg, Lisa; Söderberg, L Daniel

    2016-07-14

    Alignment of anisotropic supermolecular building blocks is crucial to control the properties of many novel materials. In this study, the alignment process of cellulose nanofibrils (CNFs) in a flow-focusing channel has been investigated using small-angle X-ray scattering (SAXS) and modeled using the Smoluchowski equation, which requires a known flow field as input. This flow field was investigated experimentally using microparticle-tracking velocimetry and by numerically applying the two-fluid level set method. A semidilute dispersion of CNFs was modeled as a continuous phase, with a higher viscosity as compared to that of water. Furthermore, implementation of the Smoluchowski equation also needed the rotational Brownian diffusion coefficient, which was experimentally determined in a shear viscosity measurement. The order of the nanofibrils was found to increase during extension in the flow-focusing channel, after which rotational diffusion acted on the orientation distribution, driving the orientation of the fibrils toward isotropy. The main features of the alignment and dealignment processes were well predicted by the numerical model, but the model overpredicted the alignment at higher rates of extension. The apparent rotational diffusion coefficient was seen to increase steeply as the degree of alignment increased. Thus, the combination of SAXS measurements and modeling provides the necessary framework for quantified studies of hydrodynamic alignment, followed by relaxation toward isotropy. PMID:27294285

  2. Nanofibril Alignment in Flow Focusing: Measurements and Calculations.

    PubMed

    Håkansson, Karl M O; Lundell, Fredrik; Prahl-Wittberg, Lisa; Söderberg, L Daniel

    2016-07-14

    Alignment of anisotropic supermolecular building blocks is crucial to control the properties of many novel materials. In this study, the alignment process of cellulose nanofibrils (CNFs) in a flow-focusing channel has been investigated using small-angle X-ray scattering (SAXS) and modeled using the Smoluchowski equation, which requires a known flow field as input. This flow field was investigated experimentally using microparticle-tracking velocimetry and by numerically applying the two-fluid level set method. A semidilute dispersion of CNFs was modeled as a continuous phase, with a higher viscosity as compared to that of water. Furthermore, implementation of the Smoluchowski equation also needed the rotational Brownian diffusion coefficient, which was experimentally determined in a shear viscosity measurement. The order of the nanofibrils was found to increase during extension in the flow-focusing channel, after which rotational diffusion acted on the orientation distribution, driving the orientation of the fibrils toward isotropy. The main features of the alignment and dealignment processes were well predicted by the numerical model, but the model overpredicted the alignment at higher rates of extension. The apparent rotational diffusion coefficient was seen to increase steeply as the degree of alignment increased. Thus, the combination of SAXS measurements and modeling provides the necessary framework for quantified studies of hydrodynamic alignment, followed by relaxation toward isotropy.

  3. Cellular self-organization by autocatalytic alignment feedback

    PubMed Central

    Junkin, Michael; Leung, Siu Ling; Whitman, Samantha; Gregorio, Carol C.; Wong, Pak Kin

    2011-01-01

    Myoblasts aggregate, differentiate and fuse to form skeletal muscle during both embryogenesis and tissue regeneration. For proper muscle function, long-range self-organization of myoblasts is required to create organized muscle architecture globally aligned to neighboring tissue. However, how the cells process geometric information over distances considerably longer than individual cells to self-organize into well-ordered, aligned and multinucleated myofibers remains a central question in developmental biology and regenerative medicine. Using plasma lithography micropatterning to create spatial cues for cell guidance, we show a physical mechanism by which orientation information can propagate for a long distance from a geometric boundary to guide development of muscle tissue. This long-range alignment occurs only in differentiating myoblasts, but not in non-fusing myoblasts perturbed by microfluidic disturbances or other non-fusing cell types. Computational cellular automata analysis of the spatiotemporal evolution of the self-organization process reveals that myogenic fusion in conjunction with rotational inertia functions in a self-reinforcing manner to enhance long-range propagation of alignment information. With this autocatalytic alignment feedback, well-ordered alignment of muscle could reinforce existing orientations and help promote proper arrangement with neighboring tissue and overall organization. Such physical self-enhancement might represent a fundamental mechanism for long-range pattern formation during tissue morphogenesis. PMID:22193956

  4. Effect of crystal orientation on conductivity and electron mobility in single-crystal alumina

    NASA Technical Reports Server (NTRS)

    Will, Fritz G.; Delorenzi, Horst G.; Janora, Kevin H.

    1992-01-01

    The electrical conductivity of high-purity, single-crystal alumina is determined parallel to and perpendicular to the c-axis. The mean conductivity of four samples of each orientation is a factor 3.3 higher parallel to the c-axis than perpendicular to it. The conductivity as a function of temperature is attributed to extrinsic electron conduction at temperatures from 400 to 900 C, and intrinsic semiconduction at temperatures from 900 to 1300 C. In the high-temperature regime, the slope on all eight specimens is 4.7 +/- 0.1 eV. Hence, the thermal bandgap at O K is 9.4 +/- 0.2 eV.

  5. Improving ASM stepper alignment accuracy by alignment signal intensity simulation

    NASA Astrophysics Data System (ADS)

    Li, Gerald; Pushpala, Sagar M.; Bradford, Bradley; Peng, Zezhong; Gottipati, Mohan

    1993-08-01

    As photolithography technology advances into submicron regime, the requirement for alignment accuracy also becomes much tighter. The alignment accuracy is a function of the strength of the alignment signal. Therefore, a detailed alignment signal intensity simulation for 0.8 micrometers EPROM poly-1 layer on ASM stepper was done based on the process of record in the fab to reduce misalignment and improve die yield. Oxide thickness variation did not have significant impact on the alignment signal intensity. However, poly-1 thickness was the most important parameter to affect optical alignments. The real alignment intensity data versus resist thickness on production wafers was collected and it showed good agreement with the simulated results. Similar results were obtained for ONO dielectric layer at a different fab.

  6. Highly aligned vertical GaN nanowires using submonolayer metal catalysts

    DOEpatents

    Wang, George T.; Li, Qiming; Creighton, J. Randall

    2010-06-29

    A method for forming vertically oriented, crystallographically aligned nanowires (nanocolumns) using monolayer or submonolayer quantities of metal atoms to form uniformly sized metal islands that serve as catalysts for MOCVD growth of Group III nitride nanowires.

  7. Local grain orientation and strain in polycrystalline YBa2Cu3O7-δ superconductor thin films measured by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Amer, Maher S.; Maguire, John; Cai, L.; Biggers, R.; Busbee, J.; LeClair, S. R.

    2001-06-01

    We report direct measurements of local grain orientation and residual strain in polycrystalline, C-axis oriented thin YBa2Cu3O7-δ superconducting films using polarized Raman spectroscopy. Strain dependence of the Ag Raman active mode at 335 cm-1 was calibrated and used to measure local strain in the films. Our data showed that high quality films are associated with the connected path of uniform grain orientation (single crystal-like) across the film and uniform residual strain in the range of -0.3%. Nonuniform grain orientation or high angle grain boundaries and nonuniform local strains were associated with low quality films.

  8. A robust, automated alignment concept for robotics

    SciTech Connect

    Everett, L.J.; Redfield, R.C. . Dept. of Mechanical Engineering)

    1994-08-01

    A video-based pose sensor is presented that overcomes some of the common problems with typical robotic pose sensors. The Targeting and Reflective Alignment Concept (TRAC) sensor operates using the optics of reflection. TRAC is a robust sensor capable of both continuous and discrete pose sensing in the presence of a class of disturbance inputs (extraneous lighting). Key features of the sensor are its high sensitivity to orientation error, its decoupled handling of orientation and translation (without calibration transformations), and its ability to provide intuitive feedback to a human operator for tele-operation. The sensor has been shown successful at target tracking with a PUMA manipulator in the laboratory and in automatic positioning of NASA-JSC's Manipulator Development Facility (MDF) telemanipulator arm used for shuttle astronaut training.

  9. Advanced Multifunctional Properties of Aligned Carbon Nanotube-Epoxy Composites from Carbon Nanotube Aerogel Method

    NASA Astrophysics Data System (ADS)

    Tran, Thang; Liu, Peng; Fan, Zeng; Ngern, Nigel; Duong, Hai

    2015-03-01

    Unlike previous methods of making carbon nanotube (CNT) thin films, aligned CNT thin films in this work are synthesized directly from CNT aerogels in a CVD process. CH4/H2/He gases and ferrocene/thiophene catalysts are mixed and reacted in the reactor at 1200 °C to form CNT aerogel socks. By pulling out the socks with a metal rod, CNT thin films with 15-nm diameter MWNTs are aligned and produced continuously at a speed of a few meters per minute. The number of the aligned CNT thin film layers/ thickness can also be controlled well. The as-synthesized aligned CNT films are further condensed by acetone spray and post-treated by UV light. The aligned CNT films without any above post-treatment have a high electrical conductivity of 400S/cm. We also develop aligned CNT-epoxy composites by infiltrating epoxy into the above aligned CNT thin films using Vacuum Assisted Resin Transfer Molding (VARTM) method. Our cost-effective fabrication method of the aligned CNT films is more advanced for developing the composites having CNT orientation control. The mechanical, electrical and optical properties of the aligned CNT epoxy composites are measured. About 2% of the aligned CNTs can enhance significantly the electrical conductivity and hardness of aligned CNT-epoxy composite films. Effects of morphologies, volume fraction, and alignment of the CNTs on the advanced multifunctional properties of the aligned CNT-epoxy composites are also quantified.

  10. Solar Alignments of Greek Temples Revisited

    NASA Astrophysics Data System (ADS)

    Mickelson, M. E.; Higbie, C.

    2005-08-01

    The canonical opinion about the placement of Greek temples is that they are oriented east-west (Dinsmoor 1975). Major exceptions, such as the temple of Apollo at Bassae which faces approximately north-south, are noted in the literature, but many other temples are scattered across the Greek landscape in a variety of orientations but predominately (about 80 Although no surviving ancient author ever discusses the criteria for placing or orienting temples, we may assume from scattered remarks that Greeks had reasons for choosing the sites and orientations. In the last century, archaeologists and architects such as Nissen (1896), Penrose (1893) and Dinsmoor (1939), have measured the alignments of Greek temples on the Greek mainland, the west coast of Turkey, and the Aegean islands. Their data have varying degrees of precision and accuracy, as a recent paper by Papathanassiou (1994) makes clear. Parallel work done in Italy on Etruscan, Roman and Greek temples by Aveni and Romano (1994) provides further stimulus to re-investigate Greek temples. We have undertaken three field seasons in Greece in order to check previously reported alignments. Where possible, in addition to determining the orientation of foundations, we have attempted to determine the, location of doorways and other openings, placement of cult statues, horizon altitudes etc. In this preliminary study we hope to be able to discover patterns in the orientation of these temples which relate solar observations to temple ritual and thus extend Dinmoor's hypothesis. For some of these questions, we are dependent on literary and inscriptional evidence. This paper describes the preliminary measurements made over our three field seasons in Greece. Field methods and analysis of the data will be presented along with possible application. 1. Dinsmoor, W.B., The Architecture of Ancient Greece, 3rd ed. Rev. New York, 1975. 2. Nissen, H.,Das Templum,Antiquarische Untesuchungon (Berlin, 1896). 3. Penrose, F.C., Trans. Roy

  11. Alignment of atmospheric mineral dust due to electric field

    NASA Astrophysics Data System (ADS)

    Ulanowski, Z.; Bailey, J.; Lucas, P. W.; Hough, J. H.; Hirst, E.

    2007-09-01

    Optical polarimetry observations on La Palma, Canary Islands, during a Saharan dust episode show dichroic extinction consistent with the presence of vertically aligned particles in the atmosphere. Modelling of the extinction together with particle orientation indicates that the alignment could have been due to an electric field of the order of 2 kV/m. Two alternative mechanisms for the origin of the field are examined: the effect of reduced atmospheric conductivity and charging of the dust layer, the latter effect being a more likely candidate. It is concluded that partial alignment may be a common feature of Saharan dust layers. The modelling also indicates that the alignment can significantly alter dust optical depth. This "Venetian blind effect" may have decreased optical thickness in the vertical direction by as much as 10% for the case reported here.

  12. Analytical alignment tolerances for off-plane reflection grating spectroscopy

    NASA Astrophysics Data System (ADS)

    Allured, Ryan; McEntaffer, Randall T.

    2013-12-01

    Future NASA X-ray Observatories will shed light on a variety of high-energy astrophysical phenomena. Off-plane reflection gratings can be used to provide high throughput and spectral resolution in the 0.3-1.5 keV band, allowing for unprecedented diagnostics of energetic astrophysical processes. A grating spectrometer consists of multiple aligned gratings intersecting the converging beam of a Wolter-I telescope. Each grating will be aligned such that the diffracted spectra overlap at the focal plane. Misalignments will degrade both spectral resolution and effective area. In this paper we present an analytical formulation of alignment tolerances that define grating orientations in all six degrees of freedom. We verify our analytical results with raytrace simulations to fully explore the alignment parameter space. We also investigate the effect of misalignments on diffraction efficiency.

  13. AVID: A global alignment program.

    PubMed

    Bray, Nick; Dubchak, Inna; Pachter, Lior

    2003-01-01

    In this paper we describe a new global alignment method called AVID. The method is designed to be fast, memory efficient, and practical for sequence alignments of large genomic regions up to megabases long. We present numerous applications of the method, ranging from the comparison of assemblies to alignment of large syntenic genomic regions and whole genome human/mouse alignments. We have also performed a quantitative comparison of AVID with other popular alignment tools. To this end, we have established a format for the representation of alignments and methods for their comparison. These formats and methods should be useful for future studies. The tools we have developed for the alignment comparisons, as well as the AVID program, are publicly available. See Web Site References section for AVID Web address and Web addresses for other programs discussed in this paper. PMID:12529311

  14. Engineering cell alignment in vitro.

    PubMed

    Li, Yuhui; Huang, Guoyou; Zhang, Xiaohui; Wang, Lin; Du, Yanan; Lu, Tian Jian; Xu, Feng

    2014-01-01

    Cell alignment plays a critical role in various cell behaviors including cytoskeleton reorganization, membrane protein relocation, nucleus gene expression, and ECM remodeling. Cell alignment is also known to exert significant effects on tissue regeneration (e.g., neuron) and modulate mechanical properties of tissues including skeleton, cardiac muscle and tendon. Therefore, it is essential to engineer cell alignment in vitro for biomechanics, cell biology, tissue engineering and regenerative medicine applications. With advances in nano- and micro-scale technologies, a variety of approaches have been developed to engineer cell alignment in vitro, including mechanical loading, topographical patterning, and surface chemical treatment. In this review, we first present alignments of various cell types and their functionality in different tissues in vivo including muscle and nerve tissues. Then, we provide an overview of recent approaches for engineering cell alignment in vitro. Finally, concluding remarks and perspectives are addressed for future improvement of engineering cell alignment.

  15. AVID: A global alignment program.

    PubMed

    Bray, Nick; Dubchak, Inna; Pachter, Lior

    2003-01-01

    In this paper we describe a new global alignment method called AVID. The method is designed to be fast, memory efficient, and practical for sequence alignments of large genomic regions up to megabases long. We present numerous applications of the method, ranging from the comparison of assemblies to alignment of large syntenic genomic regions and whole genome human/mouse alignments. We have also performed a quantitative comparison of AVID with other popular alignment tools. To this end, we have established a format for the representation of alignments and methods for their comparison. These formats and methods should be useful for future studies. The tools we have developed for the alignment comparisons, as well as the AVID program, are publicly available. See Web Site References section for AVID Web address and Web addresses for other programs discussed in this paper.

  16. Quantitative analysis on orientation of human bone integrated with midpalatal implant by micro X-ray diffractometer

    NASA Astrophysics Data System (ADS)

    Murata, Masaru; Akazawa, Toshiyuki; Yuasa, Toshihiro; Okayama, Miki; Tazaki, Junichi; Hanawa, Takao; Arisue, Makoto; Mizoguchi, Itaru

    2012-12-01

    A midpalatal implant system has been used as the unmoved anchorage for teeth movement. An 18-year-old male patient presented with reversed occlusion and was diagnosed as malocclusion. A pure titanium fixture (lengths: 4 mm, diameter: 3.3 mm, Orthosystem®, Institute Straumann, Switzerland) was implanted into the palatal bone of the patient as the orthodontic anchorage. The implant anchorage was connected with the upper left and right first molars, and had been used for 3 years. After dynamic treatments, the titanium fixture connected with bone was removed surgically, fixed in formalin solution, and embedded in resin. Specimens were cut along the frontal section of face and the direction of longitudinal axis of the implant, stained, and observed histologically. The titanium fixture was integrated directly with compact bone showing cortical bone-like structure such as lamella and osteon. In addition, to qualitatively characterize the implant-supported human bone, the crystallinity and orientation of hydroxyapatite (HAp) phase were evaluated by the microbeam X-ray diffraction analysis. Preferential alignment of c-axis of HAp crystals was represented by the relative intensity ratio of (0 0 2)-face diffraction peak to (3 1 0)-face one. The values decreased monotonously along the direction of the lateral stress from the site near the implant thread to the distant site in all horizontal lines of the map. These results indicated that the X-ray images for the intensity of c-face in HAp revealed functionally graded distribution of cortical bone quality. The micro-scale measurements of HAp structure could be a useful method for evaluating the mechanical stress distribution in human hard tissues.

  17. TSGC and JSC Alignment

    NASA Technical Reports Server (NTRS)

    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.

  18. CELT optics Alignment Procedure

    NASA Astrophysics Data System (ADS)

    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.

  19. Alignment of CH3F in para-H2 crystal studied by IR quantum cascade laser polarization spectroscopy

    NASA Astrophysics Data System (ADS)

    Kawasaki, Hiroyuki; Mizoguchi, Asao; Kanamori, Hideto

    2016-05-01

    In order to investigate the alignment of CH3F in para-H2 crystals, high resolution polarization spectroscopy of the ν3 vibrational band is studied using a quantum cascade laser at 1040 cm-1. It is found that the main and satellite series of peaks in the ν3 vibrational band of CH3F have the same polarization dependence. This result supports the previously proposed cluster model with ortho-H2 in first and second nearest neighbor sites. The observed polarization dependence function is well described by a simple six-axis void model in which CH3F is not aligned along the c-axis of the crystal but tilted to 64.9(3)° from it.

  20. Alignment of CH3F in para-H2 crystal studied by IR quantum cascade laser polarization spectroscopy.

    PubMed

    Kawasaki, Hiroyuki; Mizoguchi, Asao; Kanamori, Hideto

    2016-05-14

    In order to investigate the alignment of CH3F in para-H2 crystals, high resolution polarization spectroscopy of the ν3 vibrational band is studied using a quantum cascade laser at 1040 cm(-1). It is found that the main and satellite series of peaks in the ν3 vibrational band of CH3F have the same polarization dependence. This result supports the previously proposed cluster model with ortho-H2 in first and second nearest neighbor sites. The observed polarization dependence function is well described by a simple six-axis void model in which CH3F is not aligned along the c-axis of the crystal but tilted to 64.9(3)° from it.

  1. Birefringence imaging and orientation of laser patterned β-BaB{sub 2}O{sub 4} crystals with bending and curved shapes in glass

    SciTech Connect

    Ogawa, Kazuki; Honma, Tsuyoshi; Komatsu, Takayuki

    2013-11-15

    Nonlinear optical β-BaB{sub 2}O{sub 4} crystals (β-BBO) with bending and curved shapes were patterned at the surface of 8Sm{sub 2}O{sub 3}–42BaO–50B{sub 2}O{sub 3} glass by laser irradiations (Yb:YVO{sub 4} laser with a wavelength of 1080 nm, power of 0.8 W, and scanning speed of 4 μm/s), and the orientation state of β-BBO crystals was examined from the birefringence imaging obtained by polarization optical microscope (POM) observations. The formation (crystallization) of β-BBO crystals follows along laser scanning direction even if the laser scanning direction changes at a certain point within the bending angle of 60°. The birefringence images indicate that the formation of highly c-axis oriented β-BBO crystals follows along laser scanning direction even if the laser scanning direction changes, and in particular the direction of the c-axis of β-BBO crystals changes gradually at the bending point. The model for the orientation of the c-axis of β-BBO near the bending point is proposed. The present study proposes that the laser-induced crystallization opens a new door for the science and technology in crystal growth engineering. - Graphical abstract: This figure shows the birefringence images obtained by the Abrio IM imaging system (λ=546 nm) for the laser-patterned β-BaB{sub 2}O{sub 4} crystal line with the bending angle of 45° in the glass. The relation between the direction of slow axis and color is also shown. It is demonstrated that the formation (crystallization) of highly c-axis oriented β-BaB{sub 2}O{sub 4} crystals follows along laser scanning direction even if the laser scanning direction changes. Display Omitted - Highlights: • β-BaB{sub 2}O{sub 4} crystals with bending and curved shapes were patterned by laser irradiations. • The orientation was examined from the birefringence imaging. • Highly c-axis oriented crystals follows along laser scanning direction. • The c-axis direction changes gradually at the bending point. • The

  2. The alignment between satellites and central galaxies: theory versus observations

    NASA Astrophysics Data System (ADS)

    Kang, X.; van den Bosch, Frank C.; Yang, Xiaohu; Mao, Shude; Mo, H. J.; Li, Cheng; Jing, Y. P.

    2007-07-01

    Recent studies have shown that the distribution of satellite galaxies is preferentially aligned with the major axis of their central galaxy. The strength of this alignment has been found to depend strongly on the colours of the satellite and central galaxies, and only weakly on the mass of the halo in which the galaxies reside. In this paper we study whether these alignment signals, and their dependence on galaxy and halo properties, can be reproduced in a hierarchical structure formation model of a ΛCDM concordance cosmology. To that extent we use a large N-body simulation which we populate with galaxies following a semi-analytical model for galaxy formation. We find that if the orientation of the central galaxy is perfectly aligned with that of its dark matter halo, then the predicted central-satellite alignment signal is much stronger than observed. If, however, the minor axis of a central galaxy is perfectly aligned with the angular momentum vector of its dark matter halo, we can accurately reproduce the observed alignment strength as a function of halo mass and galaxy colour. Although this suggests that the orientation of central galaxies is governed by the angular momentum of their dark matter haloes, we emphasize that any other scenario in which the minor axes of central galaxy and halo are misaligned by ~40° (on average) will match the data equally well. Finally, we show that dependence of the alignment strength on the colour of the central galaxy is most likely an artefact due to interlopers in the group catalogue. The dependence on the colour of the satellite galaxies, on the other hand, is real and owes to the fact that red satellites are associated with subhaloes that were more massive at their time of accretion.

  3. Automated quantification of one-dimensional nanostructure alignment on surfaces

    NASA Astrophysics Data System (ADS)

    Dong, Jianjin; Goldthorpe, Irene A.; Mohieddin Abukhdeir, Nasser

    2016-06-01

    A method for automated quantification of the alignment of one-dimensional (1D) nanostructures from microscopy imaging is presented. Nanostructure alignment metrics are formulated and shown to be able to rigorously quantify the orientational order of nanostructures within a two-dimensional domain (surface). A complementary image processing method is also presented which enables robust processing of microscopy images where overlapping nanostructures might be present. Scanning electron microscopy (SEM) images of nanowire-covered surfaces are analyzed using the presented methods and it is shown that past single parameter alignment metrics are insufficient for highly aligned domains. Through the use of multiple parameter alignment metrics, automated quantitative analysis of SEM images is shown to be possible and the alignment characteristics of different samples are able to be quantitatively compared using a similarity metric. The results of this work provide researchers in nanoscience and nanotechnology with a rigorous method for the determination of structure/property relationships, where alignment of 1D nanostructures is significant.

  4. Hydrothermal synthesis of highly crystalline ZnO nanorod arrays: Dependence of morphology and alignment on growth conditions

    NASA Astrophysics Data System (ADS)

    Azzez, Shrook A.; Hassan, Z.; Hassan, J. J.; Alimanesh, M.; Rasheed, Hiba S.; Sabah, Fayroz A.; Abdulateef, Sinan A.

    2016-07-01

    Highly oriented zinc oxide nanorod were successfully grown on seeded p-type silicone substrate by hydrothermal methode. The morphology and the crystallinty of ZnO c-axis (002) arrays were systematically studied using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) methods. The effect of seed layer pre-annealing on nanorods properties was explained according to the nucleation site of ZnO nanoparticles on silicon substrate. In addition, the variation of the equal molarity of zinc nitrate hexahydrate and hexamine concentrations in the reaction vessel play a crucial role related to the ZnO nanorods.

  5. Shear adhesion strength of aligned electrospun nanofibers.

    PubMed

    Najem, Johnny F; Wong, Shing-Chung; Ji, Guang

    2014-09-01

    Inspiration from nature such as insects' foot hairs motivates scientists to fabricate nanoscale cylindrical solids that allow tens of millions of contact points per unit area with material substrates. In this paper, we present a simple yet robust method for fabricating directionally sensitive shear adhesive laminates. By using aligned electrospun nylon-6, we create dry adhesives, as a succession of our previous work on measuring adhesion energies between two single free-standing electrospun polymer fibers in cross-cylinder geometry, randomly oriented membranes and substrate, and peel forces between aligned fibers and substrate. The synthetic aligned cylindrical solids in this study are electrically insulating and show a maximal Mode II shear adhesion strength of 27 N/cm(2) on a glass slide. This measured value, for the purpose of comparison, is 270% of that reported from gecko feet. The Mode II shear adhesion strength, based on a commonly known "dead-weight" test, is 97-fold greater than the Mode I (normal) adhesion strength of the same. The data indicate a strong shear binding on and easy normal lifting off. Anisotropic adhesion (Mode II/Mode I) is pronounced. The size and surface boundary effects, crystallinity, and bending stiffness of fibers are used to understand these electrospun nanofibers, which vastly differ from otherwise known adhesive technologies. The anisotropic strength distribution is attributed to a decreasing fiber diameter and an optimized laminate thickness, which, in turn, influences the bending stiffness and solid-state "wettability" of points of contact between nanofibers and surface asperities.

  6. Polymeric templating and alignment of fullerenes

    NASA Astrophysics Data System (ADS)

    Kincer, Matthew Ryan

    Fullerene research has advanced to elevated levels in a short period of time due to the unique chemical and physical properties of the caged molecule that have been utilized in numerous applications. Due to the spherical shape of the fullerene molecule which allows for a hollow cavity, encapsulation of atoms or small molecules can occur within the ball structure. This encapsulation creates an endohedral component that is limited from interacting with other molecules which creates potential of control over electronic information of the isolated molecule. Endohedral fullerenes have the potential as serving as the base unit in a quantum computer if control over global alignment is attained. Thus, by using the inherent self-assembling capabilities of some organic materials, ordered endohedral fullerenes can be achieved. This dissertation investigates the ability to use self-assembling strategies to obtain alignment which include ordering within a morphologically controlled copolymer matrix, forming a supramolecular polymer complex with cyclodextrin, and encapsulation within the helical wrap of polymer chains. The ultimate goal is to understand the dynamics that control association and orientation of varying fullerene-based molecules in each strategy in order to maximize control over the final alignment of endohedral elements.

  7. Functionalization of vertically aligned carbon nanotubes

    PubMed Central

    Snyders, Rony; Colomer, Jean-François

    2013-01-01

    Summary This review focuses and summarizes recent studies on the functionalization of carbon nanotubes oriented perpendicularly to their substrate, so-called vertically aligned carbon nanotubes (VA-CNTs). The intrinsic properties of individual nanotubes make the VA-CNTs ideal candidates for integration in a wide range of devices, and many potential applications have been envisaged. These applications can benefit from the unidirectional alignment of the nanotubes, the large surface area, the high carbon purity, the outstanding electrical conductivity, and the uniformly long length. However, practical uses of VA-CNTs are limited by their surface characteristics, which must be often modified in order to meet the specificity of each particular application. The proposed approaches are based on the chemical modifications of the surface by functionalization (grafting of functional chemical groups, decoration with metal particles or wrapping of polymers) to bring new properties or to improve the interactions between the VA-CNTs and their environment while maintaining the alignment of CNTs. PMID:23504581

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

    NASA Astrophysics Data System (ADS)

    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. Influence of Gas Flow Rate for Formation of Aligned Nanorods in ZnO Thin Films for Solar-Driven Hydrogen Production

    SciTech Connect

    Shet, S.; Chen, L.; Tang, H.; Nuggehalli, R.; Wang, H.; Yan, Y.; Turner, J.; Al-Jassim, M.

    2012-04-01

    ZnO thin films have been deposited in mixed Ar/N{sub 2} gas ambient at substrate temperature of 500 C by radiofrequency sputtering of ZnO targets. We find that an optimum N{sub 2}-to-Ar ratio in the deposition ambient promotes the formation of well-aligned nanorods. ZnO thin films grown in ambient with 25% N{sub 2} gas flow rate promoted nanorods aligned along c-axis and exhibit significantly enhanced photoelectrochemical (PEC) response, compared with ZnO thin films grown in an ambient with different N{sub 2}-to-Ar gas flow ratios. Our results suggest that chamber ambient is critical for the formation of aligned nanostructures, which offer potential advantages for improving the efficiency of PEC water splitting for H{sub 2} production.

  10. Vertically aligned biaxially textured molybdenum thin films

    SciTech Connect

    Krishnan, Rahul; Riley, Michael; Lee, Sabrina; Lu, Toh-Ming

    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.

  11. Pareto optimal pairwise sequence alignment.

    PubMed

    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.

  12. Intrinsic alignments in redMaPPer clusters - I. Central galaxy alignments and angular segregation of satellites

    NASA Astrophysics Data System (ADS)

    Huang, Hung-Jin; Mandelbaum, Rachel; Freeman, Peter E.; Chen, Yen-Chi; Rozo, Eduardo; Rykoff, Eli; Baxter, Eric J.

    2016-08-01

    The shapes of cluster central galaxies are not randomly oriented, but rather exhibit coherent alignments with the shapes of their parent clusters as well as with the surrounding large-scale structures. In this work, we aim to identify the galaxy and cluster quantities that most strongly predict the central galaxy alignment phenomenon among a large parameter space with a sample of 8237 clusters and 94817 members within 0.1 < z < 0.35, based on the redMaPPer cluster catalog constructed from the Sloan Digital Sky Survey. We first quantify the alignment between the projected central galaxy shapes and the distribution of member satellites, to understand what central galaxy and cluster properties most strongly correlate with these alignments. Next, we investigate the angular segregation of satellites with respect to their central galaxy major axis directions, to identify the satellite properties that most strongly predict their angular segregation. We find that central galaxies are more aligned with their member galaxy distributions in clusters that are more elongated and have higher richness, and for central galaxies with larger physical size, higher luminosity and centering probability, and redder color. Satellites with redder color, higher luminosity, located closer to the central galaxy, and with smaller ellipticity show a stronger angular segregation toward their central galaxy major axes. Finally, we provide physical explanations for some of the identified correlations, and discuss the connection to theories of central galaxy alignments, the impact of primordial alignments with tidal fields, and the importance of anisotropic accretion.

  13. Pattern orientation in finite domains without boundaries

    NASA Astrophysics Data System (ADS)

    Rapp, Lisa; Bergmann, Fabian; Zimmermann, Walter

    2016-01-01

    We investigate the orientation of nonlinear stripe patterns in finite domains. Motivated by recent experiments, we introduce a control parameter drop from supercritical inside a domain to subcritical outside without boundary conditions at the domain border. As a result, stripes align perpendicularly to shallow control parameter drops. For steeper drops, non-adiabatic effects lead to a surprising orientational transition to parallel stripes with respect to the borders. We demonstrate this effect in terms of the Brusselator model and generic amplitude equations.

  14. Nova laser alignment control system

    SciTech Connect

    Van Arsdall, P.J.; Holloway, F.W.; McGuigan, D.L.; Shelton, R.T.

    1984-03-29

    Alignment of the Nova laser requires control of hundreds of optical components in the ten beam paths. Extensive application of computer technology makes daily alignment practical. The control system is designed in a manner which provides both centralized and local manual operator controls integrated with automatic closed loop alignment. Menudriven operator consoles using high resolution color graphics displays overlaid with transport touch panels allow laser personnel to interact efficiently with the computer system. Automatic alignment is accomplished by using image analysis techniques to determine beam references points from video images acquired along the laser chain. A major goal of the design is to contribute substantially to rapid experimental turnaround and consistent alignment results. This paper describes the computer-based control structure and the software methods developed for aligning this large laser system.

  15. Dust alignment in astrophysical environments

    NASA Astrophysics Data System (ADS)

    Lazarian, Alex; Thiem Hoang, Chi

    Dust is known to be aligned in interstellar medium and the arising polarization is extensively used to trace magnetic fields. What process aligns dust grains was one of the most long-standing problems of astrophysics in spite of the persistent efforts to solve it. For years the Davis-Greenstein paramagnetic alignment was the primary candidate for explaining grain alignment. However, the situation is different now and the most promising mechanism is associated with radiative torques (RATs) acting on irregular grains. I shall present the analytical theory of RAT alignment, discuss the observational tests that support this theory. I shall also discuss in what situations we expect to see the dominance of paramagnetic alignment.

  16. Onorbit IMU alignment error budget

    NASA Technical Reports Server (NTRS)

    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.

  17. [Alignment of malpositioned canines].

    PubMed

    Wagner, L

    1991-03-01

    This article presents a system for aligning impacted canines. The base of this system is the lingual arch, a rigid reaction unit of four teeth, molars and premolars. From this base unit an impacted canine can be extruded, moved distally, jumped over the occlusion and derotated by segment arches, coil springs and elastic ligatures. The efficiency of this appliance is due to the elimination of undesired reactive forces, the safe moving of teeth, the possibility of an exact force application and the simple manipulation; also the esthetic inconvenience is minimal. All this results in a better prognosis and an essentially shorter treatment time. This appliance can be used in the upper and the lower jaw. Schematic drawings and clinical examples demonstrate this method.

  18. Lunar Alignments - Identification and Analysis

    NASA Astrophysics Data System (ADS)

    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.

  19. Current-voltage characteristics of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8-{delta}} in the c-axis direction

    SciTech Connect

    Takeya, J.; Akita, S.; Kishio, K.

    1997-06-01

    Current-voltage (I-V) characteristics of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} single crystals were measured in the c-axis direction as a function of temperature and magnetic field parallel to the current. In order to eliminate heating effect, a voltage pulse with a width of 0.5 - 1 {mu}s was applied for each I-V point. The authors found an ohmic region far below the gap voltage. The ohmic resistance increased with decreasing temperature and grew 30 times larger at 4.2 K than that at room temperature. Magnetic field strongly suppressed the critical current but did not change this ohmic resistance. These behaviors can be explained by a semiconductive shunt resistance connected in parallel to a stack of Josephson junctions. By applying two-step voltage pulses, the authors observed a hysteretic feature of the intrinsic Josephson junctions. Crystals with different oxygen contents showed a large variation in critical current, normal resistance, the shunt resistance at low temperature and the degree of hysteresis due to a difference in anisotropy ratios. Utilizing the bistability revealed by the hysteretic feature, the Bi2212 crystal can function as a switching device in the c-direction. A natural stack of many junctions will exhibit large response voltage, which is a great advantage for application to power devices.

  20. Industrial Orientation.

    ERIC Educational Resources Information Center

    Rasor, Leslie; Brooks, Valerie

    These eight modules for an industrial orientation class were developed by a project to design an interdisciplinary program of basic skills training for disadvantaged students in a Construction Technology Program (see Note). The Drafting module overviews drafting career opportunities, job markets, salaries, educational requirements, and basic…

  1. Cattle on pastures do align along the North-South axis, but the alignment depends on herd density.

    PubMed

    Slaby, P; Tomanova, K; Vacha, M

    2013-08-01

    Alignment is a spontaneous behavioral preference of particular body orientation that may be seen in various vertebrate or invertebrate taxa. Animals often optimize their positions according to diverse directional environmental factors such as wind, stream, slope, sun radiation, etc. Magnetic alignment represents the simplest directional response to the geomagnetic field and a growing body of evidence of animals aligning their body positions according to geomagnetic lines whether at rest or during feedings is accumulating. Recently, with the aid of Google Earth application, evidence of prevailing North-South (N-S) body orientation of cattle on pastures was published (Begall et al. PNAS 105:13451-13455, 2008; Burda et al. PNAS 106:5708-5713, 2009). Nonetheless, a subsequent study from a different laboratory did not confirm this phenomenon (Hert et al. J Comp Physiol A 197:677-682, 2011). The aim of our study was to enlarge the pool of independently gained data on this remarkable animal behavior. By satellite snapshots analysis and using blinded protocol we scored positions of 2,235 individuals in 74 herds. Our results are in line with the original findings of prevailing N-S orientation of grazing cattle. In addition, we found that mutual distances between individual animals within herds (herd density) affect their N-S preference-a new phenomenon giving some insight into biological significance of alignment. PMID:23700176

  2. The Stonehenge technique. A method for aligning coherent bremsstrahlung radiators

    NASA Astrophysics Data System (ADS)

    Livingston, Ken

    2009-05-01

    This paper describes a technique for the alignment of crystal radiators used to produce high energy, linearly polarized photons via coherent bremsstrahlung scattering at electron beam facilities. In these experiments the crystal is mounted on a goniometer which is used to adjust its orientation relative to the electron beam. The angles and equations which relate the crystal lattice, goniometer and electron beam direction are presented here, and the method of alignment is illustrated with data taken at MAMI (the Mainz microtron). A practical guide to setting up a coherent bremsstrahlung facility and installing new crystals using this technique is also included.

  3. Alignment of the diamond nitrogen vacancy center by strain engineering

    SciTech Connect

    Karin, Todd; Dunham, Scott; Fu, Kai-Mei

    2014-08-04

    The nitrogen vacancy (NV) center in diamond is a sensitive probe of magnetic field and a promising qubit candidate for quantum information processing. The performance of many NV-based devices improves by aligning the NV(s) parallel to a single crystallographic direction. Using ab initio theoretical techniques, we show that NV orientation can be controlled by high-temperature annealing in the presence of strain under currently accessible experimental conditions. We find that (89 ± 7)% of NVs align along the [111] crystallographic direction under 2% compressive biaxial strain (perpendicular to [111]) and an annealing temperature of 970 °C.

  4. Physical Continuity and Vertical Alignment of Block Copolymer Domains by Kinetically Controlled Electrospray Deposition.

    PubMed

    Hu, Hanqiong; Choo, Youngwoo; Feng, Xunda; Osuji, Chinedum O

    2015-07-01

    The fabrication of block copolymer (BCP) thin films is reported with vertically aligned cylindrical domains using continuous electrospray deposition onto bare wafer surfaces. The out-of-plane orientation of hexagonally packed styrene cylinders is achieved in the "fast-wet" deposition regime in which rapid evaporation of the solvent in deposited droplets of polymer solution drives the vertical alignment of the self-assembled structure. Thermally activated crosslinking of the polybutadiene matrix provides kinetic control of the morphology, freezing the vertical alignment and preventing relaxation of the system to its preferred parallel orientation on the nontreated substrate. Physically continuous vertically oriented domains can be achieved over several micrometers of film thickness. The ability of electrospray deposition to fabricate well-ordered and aligned BCP films on nontreated substrates, the low amount of material used relative to spin-coating, and the continuous nature of the deposition may open up new opportunities for BCP thin films. PMID:25959572

  5. Novel liquid-crystal alignment method using polarized laser light (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Sun, Shao-Tang; Gibbons, Wayne M.; Shannon, Paul J.

    1992-10-01

    The control of liquid crystal alignment is of critical importance to the electro-optic performance of a liquid crystal display. Recently a new alignment method was discovered. Instead of the conventional buffing technique, polarized light is employed to treat the polymer alignment layer on the substrate of the display cell for the control of liquid crystal orientation. This non-contact method of aligning liquid crystals offers unique possibilities for display cell repair or reconfiguration after cell assembly. In addition, novel liquid crystal phase devices can be realized for use in optical processing.

  6. Null test fourier domain alignment technique for phase-shifting point diffraction interferometer

    DOEpatents

    Naulleau, Patrick; Goldberg, Kenneth Alan

    2000-01-01

    Alignment technique for calibrating a phase-shifting point diffraction interferometer involves three independent steps where the first two steps independently align the image points and pinholes in rotation and separation to a fixed reference coordinate system, e.g, CCD. Once the two sub-elements have been properly aligned to the reference in two parameters (separation and orientation), the third step is to align the two sub-element coordinate systems to each other in the two remaining parameters (x,y) using standard methods of locating the pinholes relative to some easy to find reference point.

  7. Vestibular compensation and orientation during locomotion

    NASA Technical Reports Server (NTRS)

    Raphan, T.; Imai, T.; Moore, S. T.; Cohen, B.

    2001-01-01

    Body, head, and eye movements were studied in three dimensions while walking and turning to determine the role of the vestibular system in directing gaze and maintaining spatial orientation. The body, head, and eyes were represented as three-dimensional coordinate frames, and the movement of these frames was related to a trajectory frame that described the motion of the body on a terrestrial plane. The axis-angle of the body, head, and eye rotation were then compared to the axis-angle of the rotation of the gravitoinertial acceleration (GIA). We inferred the role of the vestibular system during locomotion and the contributions of the VCR and VOR by examining the interrelationship between these coordinate frames. Straight walking induced head and eye rotations in a compensatory manner to the linear accelerations, maintaining head pointing and gaze along the direction of forward motion. Turning generated a combination of compensation and orientation responses. The head leads and steers the turn while the eyes compensate to maintain stable horizontal gaze in space. Saccades shift horizontal gaze as the turn is executed. The head pitches, as during straight walking. It also rolls so that the head tends to align with the orientation of the GIA. Head orientation changes anticipate orientation changes of the GIA. Eye orientation follows the changes in GIA orientation so that the net orientation gaze is closer to the orientation of the GIA. The study indicates that the vestibular system utilizes compensatory and orienting mechanisms to stabilize spatial orientation and gaze during walking and turning.

  8. Uniaxial alignment of liquid-crystalline conjugated polymers by nanoconfinement.

    PubMed

    Zheng, Zijian; Yim, Keng-Hoong; Saifullah, Mohammad S M; Welland, Mark E; Friend, Richard H; Kim, Ji-Seon; Huck, Wilhelm T S

    2007-04-01

    We demonstrate the uniaxial alignment of a liquid-crystalline conjugated polymer, poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) by means of nanoconfinement during nanoimprinting. The orientation of the conjugated backbones was parallel to the nanolines imprinted into the polymer film. Polarized UV-vis absorption and photoluminescence spectra were measured to quantify the degree of alignment, showing that the polarization ratio and uniaxial molecular order parameter were as high as 66 and 0.97, respectively. The aligned F8BT film was used as the active layer in a PLED, which resulted in polarized electroluminescence with a polarization ratio of 11. Ambipolar PFET in a top-gate configuration with aligned F8BT as the active semiconducting layer showed mobility enhancement when the chains were aligned parallel to the transport direction. Mobility anisotropies for hole and electron transport were 10-15 and 5-7, respectively, for current flow parallel and perpendicular to the alignment direction.

  9. Lexical alignment in triadic communication.

    PubMed

    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. Drive alignment pays maintenance dividends

    SciTech Connect

    Fedder, R.

    2008-12-15

    Proper alignment of the motor and gear drive on conveying and processing equipment will result in longer bearing and coupling life, along with lower maintenance costs. Selecting an alignment free drive package instead of a traditional foot mounted drive and motor is a major advancement toward these goals. 4 photos.

  11. CATO: The Clone Alignment Tool.

    PubMed

    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. Transformation and Alignment in Similarity

    ERIC Educational Resources Information Center

    Hodgetts, Carl J.; Hahn, Ulrike; Chater, Nick

    2009-01-01

    This paper contrasts two structural accounts of psychological similarity: structural alignment (SA) and Representational Distortion (RD). SA proposes that similarity is determined by how readily the structures of two objects can be brought into alignment; RD measures similarity by the complexity of the transformation that "distorts" one…

  13. CATO: The Clone Alignment Tool.

    PubMed

    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. PMID:27459605

  14. CATO: The Clone Alignment Tool

    PubMed Central

    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. PMID:27459605

  15. Lexical alignment in triadic communication

    PubMed Central

    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. PMID:25762955

  16. Curriculum Alignment: Theory to Practice.

    ERIC Educational Resources Information Center

    Leitzel, Thomas C.; Vogler, Daniel E.

    Curriculum alignment is the conscious congruence of three educational elements: curriculum, instruction, and assessment. Alignment is rooted in the belief that instructional plans are established through outcomes-based content goals and the goal of assuring that delivery and assessment are congruent. Platform unity, based on the Principles of…

  17. Well-pump alignment system

    DOEpatents

    Drumheller, Douglas S.

    1998-01-01

    An improved well-pump for geothermal wells, an alignment system for a well-pump, and to a method for aligning a rotor and stator within a well-pump, wherein the well-pump has a whistle assembly formed at a bottom portion thereof, such that variations in the frequency of the whistle, indicating misalignment, may be monitored during pumping.

  18. Botulinum alignment for congenital esotropia.

    PubMed Central

    Ing, M R

    1992-01-01

    This is the first report of a group of patients with congenital esotropia examined for motor and sensory evidence of binocularity a minimum of 3 years after alignment by botulinum. Evidence for binocularity was clearly present in approximately one half of the patients. Lag time to satisfactory alignment was at least 1 month (average, 5 months) following the initial botulinum injection. The results must be considered preliminary. However, when these results are compared with those of patients with congenital esotropia aligned by incisional surgery by age 2 years and examined with the same testing devices by this same investigator, botulinum alignment appears to be less effective than surgical alignment in establishing evidence for binocularity (P < 0.005). PMID:1494828

  19. Assessment of crystal quality and unit cell orientation in epitaxial Cu₂ZnSnSe₄ layers using polarized Raman scattering.

    PubMed

    Krämmer, Christoph; Lang, Mario; Redinger, Alex; Sachs, Johannes; Gao, Chao; Kalt, Heinz; Siebentritt, Susanne; Hetterich, Michael

    2014-11-17

    We use polarization-resolved Raman spectroscopy to assess the crystal quality of epitaxial kesterite layers. It is demonstrated for the example of epitaxial Cu₂ZnSnSe₄ layers on GaAs(001) that "standing" and "lying" kesterite unit cell orientations (c'-axis parallel / perpendicular to the growth direction) can be distinguished by the application of Raman tensor analysis. From the appearance of characteristic intensity oscillations when the sample is rotated one can distinguish polycrystalline and epitaxial layers. The method can be transferred to kesterite layers oriented in any crystal direction and can shed light on the growth of such layers in general. PMID:25402065

  20. Space Mirror Alignment System

    NASA Technical Reports Server (NTRS)

    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.

  1. Magnetic alignment and the Poisson alignment reference system

    NASA Astrophysics Data System (ADS)

    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. Alignment technology for backside integration

    NASA Astrophysics Data System (ADS)

    Bauer, J.; Kulse, P.; Haak, U.; Old, G.; Scheuring, G.; Döbereiner, St.; Hillmann, F.; Brück, H.-J.; Kaynak, M.; Ehwald, K.-E.; Marschmeyer, St.; Birkholz, M.; Schulz, K.

    2011-03-01

    This paper presents a backside-to-frontside alignment technique for the backside processing of Si wafers. Integrated MEMS components like BiCMOS-embedded RF-MEMS switches require accurate (1-2μm) alignment. We demonstrate an alignment technique providing overlay values of less than 500 nm by using a backside alignment layer. The approach is enabled by a new non-contact wafer pre-alignment system of the Nikon Scanner S207D allowing precise loading (<5μm) of the wafer onto the exposure stage. Before starting the back-side MEMS process, the misalignment between frontside devices and backside alignment layer has to be measured. The alignment errors are applied as lithography overlay corrections to the backside MEMS process. For the specific application of deep Si etching (Bosch process), moreover, one has to consider the etch profile angle deviation across the wafer (tilting), which turned out in our experiments to amount up to 8 μm. During initial experiments with a Nikon i-line stepper NSR-2205 i- 11D the overlay has been corrected by the stepper offset parameters. These parameters have been obtained by summing up both the wafer and intra-field scaling errors caused by deep Si etching and backside-to-frontside alignment errors. Misalignments and tilting errors were all measured with a MueTec MT 3000 IR optical metrology system using overlay marks. The developed alignment technique is applied to BiCMOS-embedded MEMS devices, i.e. mm-wave RF switches and a viscosity sensor chip based on the IHP's high-speed SiGe technology. It turned out to be very promising for backside processed MEMS components with critical alignment requirements.

  3. Testing the tidal alignment model of galaxy intrinsic alignment

    SciTech Connect

    Blazek, Jonathan; Seljak, Uroš; McQuinn, Matthew E-mail: mmcquinn@berkeley.edu

    2011-05-01

    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{sub 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{sub g}(r{sub p},θ), a recently developed statistic that generalizes the galaxy correlation function to account for the angle between the galaxy separation vector and the principle axis of ellipticity. We show that recent measurements are largely consistent with the tidal alignment model and discuss dependence on galaxy luminosity. In addition, we show that at linear order the tidal alignment model predicts that the angular dependence of w{sub g}(r{sub p},θ) is simply w{sub g+}(r{sub p})cos (2θ) and that this dependence is consistent with recent measurements. We also study how stochastic nonlinear contributions to galaxy ellipticity impact these statistics. We find that a significant fraction of the observed LRG ellipticity can be explained by alignment with the tidal field on scales ∼> 10 \\hMpc. These considerations are relevant to galaxy formation and evolution.

  4. Aligning Service Requirements with Business Strategy: A Proposed Stakeholder Value Model for SOA

    NASA Astrophysics Data System (ADS)

    Luthria, H.; Aurum, A.; Low, G. C.; Rabhi, F. A.

    Value-based requirements engineering plays a critical role in software development because it seeks to align requirements with the organizational strategy that drives business value. This chapter discusses the value proposition of service-oriented architectures and proposes a value-based decision mechanism for requirements engineering for service-oriented systems. In doing so, it lays the groundwork for future research into the important but relatively unexplored area of service-oriented requirements engineering.

  5. Recrystallization fabrics of sheared quartz veins with a strong pre-existing crystallographic preferred orientation from a seismogenic shear zone

    NASA Astrophysics Data System (ADS)

    Price, Nancy A.; Song, Won Joon; Johnson, Scott E.; Gerbi, Christopher C.; Beane, Rachel J.; West, David P.

    2016-07-01

    Microstructural investigations were carried out on quartz veins in schist, protomylonite, and mylonite samples from an ancient seismogenic strike-slip shear zone (Sandhill Corner shear zone, Norumbega fault system, Maine, USA). We interpret complexities in the microstructural record to show that: (1) pre-existing crystallographic preferred orientations (CPO) in the host rock may persist in the new CPO patterns of the shear zone and (2) the inner and outer parts of the shear zone followed diverging paths of fabric development. The host rocks bounding the shear zone contain asymmetrically-folded quartz veins with a strong CPO. These veins are increasingly deformed and recrystallized with proximity to the shear zone core. Matrix-accommodated rotation and recrystallization may position an inherited c-axis maximum in an orientation coincident with rhomb < a > or basal < a > slip. This inherited CPO likely persists in the shear zone fabric as a higher concentration of poles in one hemisphere of the c-axis pole figure, leading to asymmetric crossed girdle or paired maxima c-axis patterns about the foliation plane. Three observed quartz grain types indicate a general trend of localization with decreasing temperature: (1) large (> 100 μm), low aspect ratio (<~5) and (2) high aspect ratio (~ 5-20) grains overprinted by (3) smaller (<~80 μm), low aspect ratio (<~4) grains through subgrain rotation-dominated recrystallization. In the outer shear zone, subgrain rotation recrystallization led to a well-developed c-axis crossed girdle pattern. In the inner shear zone, the larger grains are completely overprinted by smaller grains, but the CPO patterns are relatively poorly developed and are associated with distinctively different misorientation angle histogram profiles ("flat" neighbor-pair profile with similar number fraction for angles from 10 to 90°). This may reflect the preferential activation of grain size sensitive deformation processes in the inner-most part of the

  6. GATA: A graphic alignment tool for comparative sequenceanalysis

    SciTech Connect

    Nix, David A.; Eisen, Michael B.

    2005-01-01

    Several problems exist with current methods used to align DNA sequences for comparative sequence analysis. Most dynamic programming algorithms assume that conserved sequence elements are collinear. This assumption appears valid when comparing orthologous protein coding sequences. Functional constraints on proteins provide strong selective pressure against sequence inversions, and minimize sequence duplications and feature shuffling. For non-coding sequences this collinearity assumption is often invalid. For example, enhancers contain clusters of transcription factor binding sites that change in number, orientation, and spacing during evolution yet the enhancer retains its activity. Dotplot analysis is often used to estimate non-coding sequence relatedness. Yet dot plots do not actually align sequences and thus cannot account well for base insertions or deletions. Moreover, they lack an adequate statistical framework for comparing sequence relatedness and are limited to pairwise comparisons. Lastly, dot plots and dynamic programming text outputs fail to provide an intuitive means for visualizing DNA alignments.

  7. CMP-compatible alignment strategy

    NASA Astrophysics Data System (ADS)

    Rouchouze, Eric; Darracq, Jean-Michel; Gemen, Jack

    1997-07-01

    As semiconductor technology continues its way towards smaller geometries, CMP has gained acceptance as the planarization technique for interconnect layers. Its benefits are well known, especially in terms of imaging. However, one of its major drawbacks is to make difficult the alignment of interconnect layers, since a planarized alignment mark is less visible for the stepper's alignment system. Usual workarounds include the clearing of process layers from the alignment mark before exposing the product layer. Although these workarounds provide a temporary solution, they are too costly to be viable in a mass production environment. In this experiment, a non-zero alignment strategy using new mark designs has been tested on the backend layers of a 0.35 micrometers CMOS process. New mark designs have been evaluated, where the space part of the gratings has been filled with 'segments' of various width, the purpose being to minimize the planarization effect of the metallization process. For the selection of the best mark design, several criteria have been taken into account: the stepper's built-in alignment diagnostic software provides information on the quality of the alignment signal. The most important criterion is the product overlay measurement and its repeatability. Marks cross sections using a FIB/SEM tool give indications on the mark profile after metal deposition.

  8. Advanced Mask Aligner Lithography (AMALITH)

    NASA Astrophysics Data System (ADS)

    Voelkel, Reinhard; Vogler, Uwe; Bramati, Arianna

    2015-03-01

    Mask aligner lithography is very attractive for less-critical lithography layers and is widely used for LED, display, CMOS image sensor, micro-fluidics and MEMS manufacturing. Mask aligner lithography is also a preferred choice the semiconductor back-end for 3D-IC, TSV interconnects, advanced packaging (AdP) and wafer-level-packaging (WLP). Mask aligner lithography is a mature technique based on shadow printing and has not much changed since the 1980s. In shadow printing lithography a geometric pattern is transferred by free-space propagation from a photomask to a photosensitive layer on a wafer. The inherent simplicity of the pattern transfer offers ease of operation, low maintenance, moderate capital expenditure, high wafers-per-hour (WPH) throughput, and attractive cost-of-ownership (COO). Advanced mask aligner lithography (AMALITH) comprises different measures to improve shadow printing lithography beyond current limits. The key enabling technology for AMALITH is a novel light integrator systems, referred to as MO Exposure Optics® (MOEO). MOEO allows to fully control and shape the properties of the illumination light in a mask aligner. Full control is the base for accurate simulation and optimization of the shadow printing process (computational lithography). Now photolithography enhancement techniques like customized illumination, optical proximity correction (OPC), phase masks (AAPSM), half-tone lithography and Talbot lithography could be used in mask aligner lithography. We summarize the recent progress in advanced mask aligner lithography (AMALITH) and discuss possible measures to further improve shadow printing lithography.

  9. Novel chelate-induced magnetic alignment of biological membranes.

    PubMed Central

    Prosser, R S; Volkov, V B; Shiyanovskaya, I V

    1998-01-01

    A phospholipid chelate complexed with ytterbium (DMPE-DTPA:Yb3+) is shown to be readily incorporated into a model membrane system, which may then be aligned in a magnetic field such that the average bilayer normal lies along the field. This so-called positively ordered smectic phase, whose lipids consist of less than 1% DMPE-DTPA:Yb3+, is ideally suited to structural studies of membrane proteins by solid-state NMR, low-angle diffraction, and spectroscopic techniques that require oriented samples. The chelate, 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine diethylenetriaminepentaacetic acid, which strongly binds the lanthanide ions and serves to orient the membrane in a magnetic field, prevents direct lanthanide-protein interactions and significantly reduces paramagnetic shifts and line broadening. Similar low-spin lanthanide chelates may have applications in field-ordered solution NMR studies of water-soluble proteins and in the design of new magnetically aligned liquid crystalline phases. PMID:9788910

  10. Phenylalanine-based polyarylacetylenes as enantiomer-differentiating alignment media.

    PubMed

    Krupp, Alexis; Reggelin, Michael

    2012-12-01

    Lyotropic liquid crystalline phases of a phenylalanine-based polyacetylene are introduced as new enantiodifferentiating alignment media. Based on the unusual temperature dependence of the quadrupolar splitting of the (2)H-signal of the solvent (CDCl(3)), three distinct states of the phase with different orientational properties can be identified. This offers the opportunity to measure multiple alignment data sets without changing the sample. Unexpectedly, the largest difference in the orientation of the enantiomers of isopinocampheol was found in the high temperature domain of the phase. This is even more astonishing because the helical structure of the polymer backbone seems to break down at temperatures above approximately 10 °C, leaving the stereogenic centers of the amino acid moieties in the repeating units as the only reason for the enantiodifferentiation.

  11. Aligning for Innovation - Alignment Strategy to Drive Innovation

    NASA Technical Reports Server (NTRS)

    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. MAGSAT: Vector magnetometer absolute sensor alignment determination

    NASA Technical Reports Server (NTRS)

    Acuna, M. H.

    1981-01-01

    A procedure is described for accurately determining the absolute alignment of the magnetic axes of a triaxial magnetometer sensor with respect to an external, fixed, reference coordinate system. The method does not require that the magnetic field vector orientation, as generated by a triaxial calibration coil system, be known to better than a few degrees from its true position, and minimizes the number of positions through which a sensor assembly must be rotated to obtain a solution. Computer simulations show that accuracies of better than 0.4 seconds of arc can be achieved under typical test conditions associated with existing magnetic test facilities. The basic approach is similar in nature to that presented by McPherron and Snare (1978) except that only three sensor positions are required and the system of equations to be solved is considerably simplified. Applications of the method to the case of the MAGSAT Vector Magnetometer are presented and the problems encountered discussed.

  13. Fusion bonding and alignment fixture

    DOEpatents

    Ackler, Harold D.; Swierkowski, Stefan P.; Tarte, Lisa A.; Hicks, Randall K.

    2000-01-01

    An improved vacuum fusion bonding structure and process for aligned bonding of large area glass plates, patterned with microchannels and access holes and slots, for elevated glass fusion temperatures. Vacuum pumpout of all the components is through the bottom platform which yields an untouched, defect free top surface which greatly improves optical access through this smooth surface. Also, a completely non-adherent interlayer, such as graphite, with alignment and location features is located between the main steel platform and the glass plate pair, which makes large improvements in quality, yield, and ease of use, and enables aligned bonding of very large glass structures.

  14. Multiple sequence alignment with DIALIGN.

    PubMed

    Morgenstern, Burkhard

    2014-01-01

    DIALIGN is a software tool for multiple sequence alignment by combining global and local alignment features. It composes multiple alignments from local pairwise sequence similarities. This approach is particularly useful to discover conserved functional regions in sequences that share only local homologies but are otherwise unrelated. An anchoring option allows to use external information and expert knowledge in addition to primary-sequence similarity alone. The latest version of DIALIGN optionally uses matches to the PFAM database to detect weak homologies. Various versions of the program are available through Göttingen Bioinformatics Compute Server (GOBICS) at http://www.gobics.de/department/software.

  15. Uniaxial pressure effect of Metal-Insulator Transition (TMI) in oriented Sm0.55(Sr0.5Ca0.5)0.45MnO3

    NASA Astrophysics Data System (ADS)

    Arumugam, Sonachalam; Mohan Radheep, D.; Sarkar, P.; Mandal, P.; Arumugam Team; Prabhat Mandal Collaboration

    2013-06-01

    Perovskite type manganites R1 - xAxMnO3 (R: rare earth ions, A: alkaline earth ions) exhibit various fundamental phenomena like colossal magnetoresistance (CMR), phase separation, and first-order ferromagnetic (FM) to paramagnetic (PM) phase transition etc. Similar to CMR, piezoresistance (PR), the change in electrical resistance in response to external pressure, can also be important parameter for various technological applications. Several studies shows that the order of phase transition can be changed either by applying external perturbations like magnetic field, pressure (P) , etc. or internally like doping etc. SSCMO single crystal was grown using floating zone technique and the quality was carefully checked and aligned along the c axis as well as ab-plane. We have investigated the effect of uniaxial pressure (P) on electrical resistivity along the ab-plane and c - axis in a single crystal of SSCMO. A huge PR ~107 % at P = 90 MPa and a remarkable increase (~79 K/GPa) of TMI have been observed with the application of P || c - axis, while TMI decreases at the rate of ~77 K/GPa for P⊥ c axis. These values of PR and dTMI /dP are much larger than those observed in other perovskite and bilayer manganites. Hence, these materials may be used for various technological applications. The authors SA and DMR wishes to thank DST, UGC and CSIR-SRF scheme (India) for the financial support to carry out the research work.

  16. Magnetic axis alignment and the Poisson alignment reference system

    NASA Astrophysics Data System (ADS)

    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.

  17. Molecular alignment dependent electron interference in attosecond ultraviolet photoionization

    PubMed Central

    Yuan, Kai-Jun; Bandrauk, André D.

    2015-01-01

    We present molecular photoionization processes by intense attosecond ultraviolet laser pulses from numerical solutions of time-dependent Schrödinger equations. Simulations preformed on a single electron diatomic H2+ show minima in molecular photoelectron energy spectra resulting from two center interference effects which depend strongly on molecular alignment. We attribute such sensitivity to the spatial orientation asymmetry of the photoionization process from the two nuclei. A similar influence on photoelectron kinetic energies is also presented. PMID:26798785

  18. High-harmonic generation in aligned water molecules

    NASA Astrophysics Data System (ADS)

    Wang, Song; Devin, Julien; Hoffmann, Matthias; Cryan, James; Kaldun, Andreas; Bucksbaum, Philip

    2016-05-01

    In recent years, the use of high harmonic generation (HHG) in aligned molecular vapors has become a powerful tool to study ultrafast dynamics of electronic and nuclear wave packets. In our new experimental setup, we are able to orient H2 O and D2 O molecules using a single cycle terahertz (THz) pulse. Aligning water is especially interesting as the highest occupied molecular orbital (HOMO) of water contains a node in the xz plane of the molecular frame, allowing us to perform HHG from second highest occupied molecular orbital (HOMO-1) only, by setting the polarization of the fundamental laser along the z-axis of the aligned water molecules. We are particularly interested in the HOMO-1 state, as there is fast motion of the H-O-H angle leading to sub-wavelength dynamics. On this poster we present our all-optical alignment setup where HHG and single-cycle THz generation take place in high-vacuum, where measurements with arbitrary polarization angles between the two are possible. In addition, we discuss the effects of the molecular orientation on HHG, including symmetry breaking that could produce even harmonics and isotope effects between H2 O and D2 O due to different vibrational energies. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division.

  19. Dry shear aligning: a simple and versatile method to smooth and align the surfaces of carbon nanotube thin films

    NASA Astrophysics Data System (ADS)

    Tune, D. D.; Stolz, B. W.; Pfohl, M.; Flavel, B. S.

    2016-02-01

    We show that the application of lateral shear force on a randomly oriented thin film of carbon nanotubes, in the dry state, causes significant reordering of the nanotubes at the film surface. This new technique of dry shear aligning is applicable to carbon nanotube thin films produced by many of the established methods.We show that the application of lateral shear force on a randomly oriented thin film of carbon nanotubes, in the dry state, causes significant reordering of the nanotubes at the film surface. This new technique of dry shear aligning is applicable to carbon nanotube thin films produced by many of the established methods. Electronic supplementary information (ESI) available: Detailed experimental methods, table of nanotube details, absorption spectra, further SEM data, plots of sheet resistance, DC to optical conductivity, and 2D order parameter as a function of transmittance. See DOI: 10.1039/c5nr08784h

  20. Laser beam alignment apparatus and method

    DOEpatents

    Gruhn, Charles R.; Hammond, Robert B.

    1981-01-01

    The disclosure relates to an apparatus and method for laser beam alignment. Thermoelectric properties of a disc in a laser beam path are used to provide an indication of beam alignment and/or automatic laser alignment.

  1. Theory of grain alignment in molecular clouds

    NASA Technical Reports Server (NTRS)

    Roberge, Wayne G.

    1993-01-01

    Research accomplishments are presented and include the following: (1) mathematical theory of grain alignment; (2) super-paramagnetic alignment of molecular cloud grains; and (3) theory of grain alignment by ambipolar diffusion.

  2. Laser beam alignment apparatus and method

    DOEpatents

    Gruhn, C.R.; Hammond, R.B.

    The disclosure related to an apparatus and method for laser beam alignment. Thermoelectric properties of a disc in a laser beam path are used to provide an indication of beam alignment and/or automatic laser alignment.

  3. Protein structure alignment beyond spatial proximity.

    PubMed

    Wang, Sheng; Ma, Jianzhu; Peng, Jian; Xu, Jinbo

    2013-01-01

    Protein structure alignment is a fundamental problem in computational structure biology. Many programs have been developed for automatic protein structure alignment, but most of them align two protein structures purely based upon geometric similarity without considering evolutionary and functional relationship. As such, these programs may generate structure alignments which are not very biologically meaningful from the evolutionary perspective. This paper presents a novel method DeepAlign for automatic pairwise protein structure alignment. DeepAlign aligns two protein structures using not only spatial proximity of equivalent residues (after rigid-body superposition), but also evolutionary relationship and hydrogen-bonding similarity. Experimental results show that DeepAlign can generate structure alignments much more consistent with manually-curated alignments than other automatic tools especially when proteins under consideration are remote homologs. These results imply that in addition to geometric similarity, evolutionary information and hydrogen-bonding similarity are essential to aligning two protein structures.

  4. Fixture for aligning motor assembly

    DOEpatents

    Shervington, Roger M.; Vaghani, Vallabh V.; Vanek, Laurence D.; Christensen, Scott A.

    2009-12-08

    An alignment fixture includes a rotor fixture, a stator fixture and a sensor system which measures a rotational displacement therebetween. The fixture precisely measures rotation of a generator stator assembly away from a NULL position referenced by a unique reference spline on the rotor shaft. By providing an adjustable location of the stator assembly within the housing, the magnetic axes within each generator shall be aligned to a predetermined and controlled tolerance between the generator interface mounting pin and the reference spline on the rotor shaft. Once magnetically aligned, each generator is essentially a line replaceable unit which may be readily mounted to any input of a multi-generator gearbox assembly with the assurance that the magnetic alignment will be within a predetermined tolerance.

  5. Well-pump alignment system

    DOEpatents

    Drumheller, D.S.

    1998-10-20

    An improved well-pump for geothermal wells, an alignment system for a well-pump, and to a method for aligning a rotor and stator within a well-pump are disclosed, wherein the well-pump has a whistle assembly formed at a bottom portion thereof, such that variations in the frequency of the whistle, indicating misalignment, may be monitored during pumping. 6 figs.

  6. Hybrid Alignment Induced by Asymmetric Photopolymerization of Liquid Crystal-Reactive Mesogen Composition between Two Plastic Substrates

    NASA Astrophysics Data System (ADS)

    Kim, Kyoung-Sun; Lee, Ji-Hoon

    2011-05-01

    A hybrid aligned liquid crystal layer was prepared between plastic substrates by the asymmetric photopolymerization of the reactive mesogen. The planar alignment of liquid crystal molecules was induced on the top substrate facing the UV light by the predominant photopolymerization at this substrate, whereas a homeotropic orientation was induced on the bottom substrate. The extinction ratio of the hybrid aligned samples vs the polymer concentration and the thickness of the liquid crystal layer was examined.

  7. BinAligner: a heuristic method to align biological networks

    PubMed Central

    2013-01-01

    The advances in high throughput omics technologies have made it possible to characterize molecular interactions within and across various species. Alignments and comparison of molecular networks across species will help detect orthologs and conserved functional modules and provide insights on the evolutionary relationships of the compared species. However, such analyses are not trivial due to the complexity of network and high computational cost. Here we develop a mixture of global and local algorithm, BinAligner, for network alignments. Based on the hypotheses that the similarity between two vertices across networks would be context dependent and that the information from the edges and the structures of subnetworks can be more informative than vertices alone, two scoring schema, 1-neighborhood subnetwork and graphlet, were introduced to derive the scoring matrices between networks, besides the commonly used scoring scheme from vertices. Then the alignment problem is formulated as an assignment problem, which is solved by the combinatorial optimization algorithm, such as the Hungarian method. The proposed algorithm was applied and validated in aligning the protein-protein interaction network of Kaposi's sarcoma associated herpesvirus (KSHV) and that of varicella zoster virus (VZV). Interestingly, we identified several putative functional orthologous proteins with similar functions but very low sequence similarity between the two viruses. For example, KSHV open reading frame 56 (ORF56) and VZV ORF55 are helicase-primase subunits with sequence identity 14.6%, and KSHV ORF75 and VZV ORF44 are tegument proteins with sequence identity 15.3%. These functional pairs can not be identified if one restricts the alignment into orthologous protein pairs. In addition, BinAligner identified a conserved pathway between two viruses, which consists of 7 orthologous protein pairs and these proteins are connected by conserved links. This pathway might be crucial for virus packing and

  8. Cooperative Ordering and Kinetics of Cellulose Nanocrystal Alignment in a Magnetic Field.

    PubMed

    De France, Kevin J; Yager, Kevin G; Hoare, Todd; Cranston, Emily D

    2016-08-01

    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.

  9. Cooperative Ordering and Kinetics of Cellulose Nanocrystal Alignment in a Magnetic Field.

    PubMed

    De France, Kevin J; Yager, Kevin G; Hoare, Todd; Cranston, Emily D

    2016-08-01

    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. PMID:27407001

  10. Electrospun fiber constructs for vocal fold tissue engineering: effects of alignment and elastomeric polypeptide coating

    PubMed Central

    Hughes, Lindsay A.; Gaston, Joel; McAlindon, Katherine; Woodhouse, Kimberly A.

    2014-01-01

    Vocal fold lamina propria extracellular matrix (ECM) is highly aligned and when injured, becomes disorganized with loss of the tissue’s critical biomechanical properties. This study examines the effects of electrospun fiber scaffold architecture and elastin-like polypeptide (ELP4) coating on human vocal fold fibroblast (HVFF) behavior for applications toward tissue engineering the vocal fold lamina propria. Electrospun Tecoflex™ scaffolds were made with aligned and unaligned fibers, and were characterized using scanning electron microscopy and uniaxial tensile testing. ELP4 was successfully adsorbed onto the scaffolds; HVFF were seeded and their viability, proliferation, morphology, and gene expression were characterized. Aligned and unaligned scaffolds had initial elastic moduli of ~14 MPa, ~5 MPa and ~0.3 MPa, ~0.6 MPa in the preferred and cross-preferred directions, respectively. Scaffold topography had an effect on the orientation of the cells, with HVFF seeded on aligned scaffolds having a significantly different (p < 0.001) angle of orientation than HVFF cultured on unaligned scaffolds. This same effect and significant difference (p < 0.001) was seen on aligned and unaligned scaffolds coated with ELP4. Scaffold alignment and ELP4 coating impacted ECM gene expression. ELP4 coating, and aligned scaffolds upregulated elastin synthesis when tested on day 7 without a concomitant upregulation of collagen III synthesis. Collectively, results indicate that aligned electrospun scaffolds and ELP4 coating, are promising candidates in the development of biodegradeable vocal fold lamina propria constructs. PMID:25462850

  11. Aligned-to-random” nanofiber scaffolds for mimicking the structure of the tendon-to-bone insertion site

    PubMed Central

    Xie, Jingwei; Li, Xiaoran; Lipner, Justin; Manning, Cionne N.; Schwartz, Annie G.; Thomopoulos, Stavros; Xia, Younan

    2013-01-01

    We have demonstrated the fabrication of “aligned-to-random” electrospun nanofiber scaffolds that mimic the structural organization of collagen fibers at the tendon-to-bone insertion site. Tendon fibroblasts cultured on such a scaffold exhibited highly organized and haphazardly oriented morphologies, respectively, on the aligned and random portions. PMID:20648290

  12. Hydroxyapatite coatings with oriented nanoplate and nanorod arrays: Fabrication, morphology, cytocompatibility and osteogenic differentiation.

    PubMed

    Chen, Wei; Tian, Bo; Lei, Yong; Ke, Qin-Fei; Zhu, Zhen-An; Guo, Ya-Ping

    2016-10-01

    Hydroxyapatite (HA) crystals exhibit rod-like shape with c-axis orientation and plate-like shape with a(b)-axis orientation in vertebrate bones and tooth enamel surfaces, respectively. Herein, we report the synthesis of HA coatings with the oriented nanorod arrays (RHACs) and HA coatings with oriented nanoplate arrays (PHACs) by using bioglass coatings as sacrificial templates. After soaking in simulated body fluid (SBF) at 120°C, the bioglass coatings are hydrothermally converted into the HA coatings via a dissolution-precipitation reaction. If the Ca/P ratios in SBF are 2.50 and 1.25, the HA crystals on the coatings are oriented nanorod arrays and oriented nanoplate arrays, respectively. Moreover, the bioglass coatings are treated with SBF at 37°C, plate-like HA coatings with a low crystallinity (SHACs) are prepared. As compared with the Ti6Al4V and SHACs, the human bone marrow stromal cells (hBMSCs) on the RHACs and PHACs have better cell adhesion, spreading, proliferation and osteogenic differentiation because of their moderately hydrophilic surfaces and similar chemical composition, morphology and crystal orientation to human hard tissues. Notably, the morphologies of HA crystals have no obvious effects on cytocompatibility and osteogenic differentiation. Hence, the HA coatings with oriented nanoplate arrays or oriented nanorod arrays have a great potential for orthopedic applications. PMID:27287136

  13. Orienting hypnosis.

    PubMed

    Hope, Anna E; Sugarman, Laurence I

    2015-01-01

    This article presents a new frame for understanding hypnosis and its clinical applications. Despite great potential to transform health and care, hypnosis research and clinical integration is impaired in part by centuries of misrepresentation and ignorance about its demonstrated efficacy. The authors contend that advances in the field are primarily encumbered by the lack of distinct boundaries and definitions. Here, hypnosis, trance, and mind are all redefined and grounded in biological, neurological, and psychological phenomena. Solutions are proposed for boundary and language problems associated with hypnosis. The biological role of novelty stimulating an orienting response that, in turn, potentiates systemic plasticity forms the basis for trance. Hypnosis is merely the skill set that perpetuates and influences trance. This formulation meshes with many aspects of Milton Erickson's legacy and Ernest Rossi's recent theory of mind and health. Implications of this hypothesis for clinical skills, professional training, and research are discussed.

  14. Pupil Alignment Considerations for Large, Deployable Space Telescopes

    NASA Technical Reports Server (NTRS)

    Bos, Brent J.; Ohl, Raymond G.; Kubalak, Daivd A.

    2011-01-01

    For many optical systems the properties and alignment of the internal apertures and pupils are not critical or controlled with high precision during optical system design, fabrication or assembly. In wide angle imaging systems, for instance, the entrance pupil position and orientation is typically unconstrained and varies over the system s field of view in order to optimize image quality. Aperture tolerances usually do not receive the same amount of scrutiny as optical surface aberrations or throughput characteristics because performance degradation is typically graceful with misalignment, generally only causing a slight reduction in system sensitivity due to vignetting. But for a large deployable space-based observatory like the James Webb Space Telescope (JWST), we have found that pupil alignment is a key parameter. For in addition to vignetting, JWST pupil errors cause uncertainty in the wavefront sensing process that is used to construct the observatory on-orbit. Furthermore they also open stray light paths that degrade the science return from some of the telescope s instrument channels. In response to these consequences, we have developed several pupil measurement techniques for the cryogenic vacuum test where JWST science instrument pupil alignment is verified. These approaches use pupil alignment references within the JWST science instruments; pupil imaging lenses in three science instrument channels; and unique pupil characterization features in the optical test equipment. This will allow us to verify and crosscheck the lateral pupil alignment of the JWST science instruments to approximately 1-2% of their pupil diameters.

  15. Separating weak lensing and intrinsic alignments using radio observations

    NASA Astrophysics Data System (ADS)

    Whittaker, Lee; Brown, Michael L.; Battye, Richard A.

    2015-07-01

    We discuss methods for performing weak lensing using radio observations to recover information about the intrinsic structural properties of the source galaxies. Radio surveys provide unique information that can benefit weak lensing studies, such as H I emission, which may be used to construct galaxy velocity maps, and polarized synchrotron radiation; both of which provide information about the unlensed galaxy and can be used to reduce galaxy shape noise and the contribution of intrinsic alignments. Using a proxy for the intrinsic position angle of an observed galaxy, we develop techniques for cleanly separating weak gravitational lensing signals from intrinsic alignment contamination in forthcoming radio surveys. Random errors on the intrinsic orientation estimates introduce biases into the shear and intrinsic alignment estimates. However, we show that these biases can be corrected for if the error distribution is accurately known. We demonstrate our methods using simulations, where we reconstruct the shear and intrinsic alignment auto- and cross-power spectra in three overlapping redshift bins. We find that the intrinsic position angle information can be used to successfully reconstruct both the lensing and intrinsic alignment power spectra with negligible residual bias.

  16. The Astronomical Orientation of Ancient Greek Temples

    PubMed Central

    Salt, Alun M.

    2009-01-01

    Despite its appearing to be a simple question to answer, there has been no consensus as to whether or not the alignments of ancient Greek temples reflect astronomical intentions. Here I present the results of a survey of archaic and classical Greek temples in Sicily and compare them with temples in Greece. Using a binomial test I show strong evidence that there is a preference for solar orientations. I then speculate that differences in alignment patterns between Sicily and Greece reflect differing pressures in the expression of ethnic identity. PMID:19936239

  17. Aligned carbon nanotube sheet piezoresistive strain sensors

    NASA Astrophysics Data System (ADS)

    Li, Ang; Bogdanovich, Alexander E.; Bradford, Philip D.

    2015-09-01

    Carbon nanotubes (CNTs) have a unique set of properties that may be useful in the production of next generation structural health monitoring composites. This research introduces a novel CNT based material system for strain and damage sensing applications. An aligned sheet of interconnected CNTs was drawn from a chemical vapor deposition grown CNT array and then bonded to the surface of glass fiber/epoxy composite coupons. Various types of mechanical tests were conducted, accompanied by real-time electrical data acquisition, in order to evaluate the electro-mechanical behavior of the developed sensing material. Specimens were loaded in the longitudinal and transverse CNT sheet orientations to investigate the anisotropy of the piezoresistive effect. The CNT sheets exhibited good sensing stability, linearity, sensitivity and repeatability within a practical strain range; which are crucial sensor features for health monitoring. It was also demonstrated that the CNT orientation in the sheet had a dramatic effect on the sensitivity, thus validating the usefulness of this sensing material for directional strain/damage monitoring. Finally, pre-straining of the CNT sheet sensors was conducted to further enhance the linearity of electro-mechanical response and long-term stability of the sensors during cyclic loading.

  18. Investigating Conversational Dynamics: Interactive Alignment, Interpersonal Synergy, and Collective Task Performance.

    PubMed

    Fusaroli, Riccardo; Tylén, Kristian

    2016-01-01

    This study investigates interpersonal processes underlying dialog by comparing two approaches, interactive alignment and interpersonal synergy, and assesses how they predict collective performance in a joint task. While the interactive alignment approach highlights imitative patterns between interlocutors, the synergy approach points to structural organization at the level of the interaction-such as complementary patterns straddling speech turns and interlocutors. We develop a general, quantitative method to assess lexical, prosodic, and speech/pause patterns related to the two approaches and their impact on collective performance in a corpus of task-oriented conversations. The results show statistical presence of patterns relevant for both approaches. However, synergetic aspects of dialog provide the best statistical predictors of collective performance and adding aspects of the alignment approach does not improve the model. This suggests that structural organization at the level of the interaction plays a crucial role in task-oriented conversations, possibly constraining and integrating processes related to alignment.

  19. Investigating Conversational Dynamics: Interactive Alignment, Interpersonal Synergy, and Collective Task Performance.

    PubMed

    Fusaroli, Riccardo; Tylén, Kristian

    2016-01-01

    This study investigates interpersonal processes underlying dialog by comparing two approaches, interactive alignment and interpersonal synergy, and assesses how they predict collective performance in a joint task. While the interactive alignment approach highlights imitative patterns between interlocutors, the synergy approach points to structural organization at the level of the interaction-such as complementary patterns straddling speech turns and interlocutors. We develop a general, quantitative method to assess lexical, prosodic, and speech/pause patterns related to the two approaches and their impact on collective performance in a corpus of task-oriented conversations. The results show statistical presence of patterns relevant for both approaches. However, synergetic aspects of dialog provide the best statistical predictors of collective performance and adding aspects of the alignment approach does not improve the model. This suggests that structural organization at the level of the interaction plays a crucial role in task-oriented conversations, possibly constraining and integrating processes related to alignment. PMID:25988263

  20. Littrow angle method to remove alignment errors in grating pulse compressors.

    PubMed

    Guardalben, M J

    2008-09-20

    An alignment method for pulse-compression gratings that obviates the need to place the gratings at normal incidence to remove grating-tip error is proposed. Grating-tip and groove-orientation errors are removed using two alignment wavelengths in a manner analogous to a laser-beam pointing and centering procedure entirely at the respective Littrow angles for the two wavelengths. By choosing wavelengths with Littrow angles close to the use angle of the grating, the residual tip and groove-orientation errors that may be introduced when the grating mount is tilted to its use angle are reduced. This method has greatly facilitated the alignment of the OMEGA Extended Performance (EP) large-aperture pulse compressors, thereby reducing residual pulse-front tilt caused by nonparallel gratings. OMEGA EP is a high-energy, petawatt-class laser at the University of Rochester's Laboratory for Laser Energetics. A numerical simulation of the alignment procedure is presented. PMID:18806858

  1. Littrow Angle Method to Remove Alignment Errors in Grating Pulse Compressors

    SciTech Connect

    Guardalben, M.J.

    2008-09-16

    An alignment method for pulse-compression gratings that obviates the need to place the gratings at normal incidence to remove grating-tip error is proposed. Grating-tip and groove-orientation errors are removed using two alignment wavelengths in a manner analogous to a laser-beam pointing and centering procedure entirely at the respective Littrow angles for the two wavelengths. By choosing wavelengths with Littrow angles close to the use angle of the grating, the residual tip and groove-orientation errors that may be introduced when the grating mount is tilted to its use angle are reduced. This method has greatly facilitated the alignment of the OMEGA Extended Performance (EP) large-aperture pulse compressors, thereby reducing residual pulse-front tilt caused by nonparallel gratings. OMEGA EP is a highenergy, petawatt-class laser at the University of Rochester’s Laboratory for Laser Energetics. A numerical simulation of the alignment procedure is presented.

  2. Littrow angle method to remove alignment errors in grating pulse compressors

    SciTech Connect

    Guardalben, M. J

    2008-09-20

    An alignment method for pulse-compression gratings that obviates the need to place the gratings at normal incidence to remove grating-tip error is proposed. Grating-tip and groove-orientation errors are removed using two alignment wavelengths in a manner analogous to a laser-beam pointing and centering procedure entirely at the respective Littrow angles for the two wavelengths. By choosing wavelengths with Littrow angles close to the use angle of the grating, the residual tip and groove-orientation errors that may be introduced when the grating mount is tilted to its use angle are reduced. This method has greatly facilitated the alignment of the OMEGA Extended Performance (EP) large-aperture pulse compressors, thereby reducing residual pulse-front tilt caused by nonparallel gratings. OMEGA EP is a high-energy, petawatt-class laser at the University of Rochester's Laboratory for Laser Energetics. A numerical simulation of the alignment procedure is presented.

  3. Comparison of lattice preferred orientation and magnetic fabric of a chloritoid-bearing slate

    NASA Astrophysics Data System (ADS)

    Haerinck, Tom; Wenk, Hans-Rudolf; Debacker, Timothy N.; Sintubin, Manuel

    2014-05-01

    A regional analysis of the anisotropy of the magnetic susceptibility (AMS) on chloritoid-bearing slates of the Paleozoic Plougastel Formation in the low-grade metamorphic conditions (epizonal) of the Monts d'Arrée slate belt in Central Armorica (Brittany, France) reveals very high values for the degree of anisotropy (PJ), up to 1.43 (Haerinck et al. 2013a). In contrast, stratigraphically equivalent slates free of chloritoid, in the very low-grade metamorphic conditions (anchizonal) of the Crozon fold-and-thrust belt, show a lower degree of anisotropy, with PJ values up to 1.27. Classically, very strong magnetic fabrics (i.e. those with PJ above 1.35) are attributed to a contribution of ferromagnetic (s.l.) minerals. Nonetheless, high-field torque magnetometry indicates that the magnetic fabric of the chloritoid-bearing slates is dominantly paramagnetic. The ferromagnetic (sensu lato) contribution to the AMS is less than 10%. Based on these observations, it would seem that chloritoid has an intrinsic magnetic anisotropy that is significantly higher than that of most paramagnetic silicates and the frequently used upper limit for the paramagnetic contribution to the AMS. Using two independent approaches, i.e. (a) directional magnetic hysteresis measurements, and (b) torque magnetometry, on a collection of single chloritoid crystals, collected from different tectonometamorphic settings worldwide, the magnetocrystalline anisotropy of monoclinic chloritoid has been determined (Haerinck et al. 2013b). The determined paramagnetic high-field AMS ellipsoids have a highly oblate shape with the minimum susceptibility direction subparallel to the crystallographic c-axis of chloritoid and the degree of anisotropy of chloritoid is found to be 1.47 ± 0.06. The obtained very high magnetocrystalline degree of anisotropy suggests that chloritoid-bearing slates with a pronounced mineral alignment can have a high degree of anisotropy (PJ) without the need of invoking a significant

  4. Intrinsic alignments in redMaPPer clusters - I. Central galaxy alignments and angular segregation of satellites

    NASA Astrophysics Data System (ADS)

    Huang, Hung-Jin; Mandelbaum, Rachel; Freeman, Peter E.; Chen, Yen-Chi; Rozo, Eduardo; Rykoff, Eli; Baxter, Eric J.

    2016-11-01

    The shapes of cluster central galaxies are not randomly oriented, but rather exhibit coherent alignments with the shapes of their parent clusters as well as with the surrounding large-scale structures. In this work, we aim to identify the galaxy and cluster quantities that most strongly predict the central galaxy alignment phenomenon among a large parameter space with a sample of 8237 clusters and 94 817 members within 0.1 < z < 0.35, based on the red-sequence Matched-filter Probabilistic Percolation cluster catalogue constructed from the Sloan Digital Sky Survey. We first quantify the alignment between the projected central galaxy shapes and the distribution of member satellites, to understand what central galaxy and cluster properties most strongly correlate with these alignments. Next, we investigate the angular segregation of satellites with respect to their central galaxy major axis directions, to identify the satellite properties that most strongly predict their angular segregation. We find that central galaxies are more aligned with their member galaxy distributions in clusters that are more elongated and have higher richness, and for central galaxies with larger physical size, higher luminosity and centring probability, and redder colour. Satellites with redder colour, higher luminosity, located closer to the central galaxy, and with smaller ellipticity show a stronger angular segregation towards their central galaxy major axes. Finally, we provide physical explanations for some of the identified correlations, and discuss the connection to theories of central galaxy alignments, the impact of primordial alignments with tidal fields, and the importance of anisotropic accretion.

  5. Constraints on the alignment of galaxies in galaxy clusters from ~14 000 spectroscopic members

    NASA Astrophysics Data System (ADS)

    Sifón, Cristóbal; Hoekstra, Henk; Cacciato, Marcello; Viola, Massimo; Köhlinger, Fabian; van der Burg, Remco F. J.; Sand, David J.; Graham, Melissa L.

    2015-03-01

    Torques acting on galaxies lead to physical alignments, but the resulting ellipticity correlations are difficult to predict. As they constitute a major contaminant for cosmic shear studies, it is important to constrain the intrinsic alignment signal observationally. We measured the alignments of satellite galaxies within 90 massive galaxy clusters in the redshift range 0.05 alignment: the radial alignment of satellite galaxies toward the brightest cluster galaxies (BCGs), the common orientations of satellite galaxies and BCGs, and the radial alignments of satellites with each other. Residual systematic effects are much smaller than the statistical uncertainties. We detect no galaxy alignment of any kind out to at least 3r200. The signal is consistent with zero for both blue and red galaxies, bright and faint ones, and also for subsamples of clusters based on redshift, dynamical mass, and dynamical state. These conclusions are unchanged if we expand the sample with bright cluster members from the red sequence. We augment our constraints with those from the literature to estimate the importance of the intrinsic alignments of satellites compared to those of central galaxies, for which the alignments are described by the linear alignment model. Comparison of the alignment signals to the expected uncertainties of current surveys such as the Kilo-Degree Survey suggests that the linear alignment model is an adequate treatment of intrinsic alignments, but it is not clear whether this will be the case for larger surveys. Table is available in electronic form at

  6. Microstructures and magnetic alignment of L10 FePt nanoparticles

    NASA Astrophysics Data System (ADS)

    Kang, Shishou; Shi, Shifan; Jia, Zhiyong; Thompson, G. B.; Nikles, David E.; Harrell, J. W.; Li, Daren; Poudyal, Narayan; Nandwana, Vikas; Liu, J. Ping

    2007-05-01

    Chemically ordered FePt nanoparticles were obtained by high temperature annealing a mixture of FePt particles with NaCl. After the NaCl was removed with de-ionized water, the transformed FePt nanoparticles were redispersed in cyclohexanone. X-ray diffraction patterns clearly show the L10 phase. Scherrer analysis indicates that the average particle size is about 8nm, which is close to the transmission electron microscopy (TEM) statistical results. The coercivity ranges from 16kOe to more than 34kOe from room temperature down to 10K. High resolution TEM images reveal that most of the FePt particles were fully transformed into the L10 phase, except for a small fraction of particles which were partially chemically ordered. Nano-energy dispersive spectroscopy measurements on the individual particles show that the composition of the fully transformed particles is close to 50/50, while the composition of the partially transformed particles is far from equiatomic. TEM images and electron diffraction patterns indicate c-axis alignment for a monolayer of L10 FePt particles formed by drying a dilute dispersion on copper grids under a magnetic field. For thick samples dried under a magnetic field, the degree of easy axis alignment is not as high as predicted due to strong interactions between particles.

  7. Schottky-contacted vertically self-aligned ZnO nanorods for hydrogen gas nanosensor applications

    SciTech Connect

    Ranwa, Sapana; Kumar, Mohit; Kumar, Mahesh; Singh, Jitendra; Fanetti, Mattia

    2015-07-21

    Vertically well aligned ZnO nanorods (NRs) were grown on Si(100) substrate using RF magnetron sputtering technique. Scanning electron microscopy images confirms uniform distribution of NRs on 2 in. wafer with average diameter, height and density being ∼75 nm, ∼850 nm, and ∼1.5 × 10{sup 10} cm{sup −2}, respectively. X-ray diffraction reveals that the ZnO NRs are grown along c-axis direction with wurtzite crystal structure. Cathodoluminescence spectroscopy, which shows a single strong peak around 3.24 eV with full width half maxima 130 meV, indicates the high crystalline and optical quality of ZnO and very low defect density. Vertically aligned nanosensors were fabricated by depositing gold circular Schottky contacts on ZnO NRs. Resistance responses of nanosensors were observed in the range from 50 to 150 °C in 1% and 5% hydrogen in argon environment, which is below and above the explosive limit (4%) of hydrogen in air. The nanosensor's sensitivity increases from 11% to 67% with temperature from 50 to 150 °C and also shows fast response time (9–16 s) and moderate recovery time (100–200 s). A sensing mechanism is proposed based on Schottky barrier changes at heterojunctions and change in depletion region of NRs.

  8. Schottky-contacted vertically self-aligned ZnO nanorods for hydrogen gas nanosensor applications

    NASA Astrophysics Data System (ADS)

    Ranwa, Sapana; Kumar, Mohit; Singh, Jitendra; Fanetti, Mattia; Kumar, Mahesh

    2015-07-01

    Vertically well aligned ZnO nanorods (NRs) were grown on Si(100) substrate using RF magnetron sputtering technique. Scanning electron microscopy images confirms uniform distribution of NRs on 2 in. wafer with average diameter, height and density being ˜75 nm, ˜850 nm, and ˜1.5 × 1010 cm-2, respectively. X-ray diffraction reveals that the ZnO NRs are grown along c-axis direction with wurtzite crystal structure. Cathodoluminescence spectroscopy, which shows a single strong peak around 3.24 eV with full width half maxima 130 meV, indicates the high crystalline and optical quality of ZnO and very low defect density. Vertically aligned nanosensors were fabricated by depositing gold circular Schottky contacts on ZnO NRs. Resistance responses of nanosensors were observed in the range from 50 to 150 °C in 1% and 5% hydrogen in argon environment, which is below and above the explosive limit (4%) of hydrogen in air. The nanosensor's sensitivity increases from 11% to 67% with temperature from 50 to 150 °C and also shows fast response time (9-16 s) and moderate recovery time (100-200 s). A sensing mechanism is proposed based on Schottky barrier changes at heterojunctions and change in depletion region of NRs.

  9. Alignment and Graphene-Assisted Decoration of Lyotropic Chromonic Liquid Crystals Containing DNA Origami Nanostructures.

    PubMed

    Martens, Kevin; Funck, Timon; Kempter, Susanne; Roller, Eva-Maria; Liedl, Tim; Blaschke, Benno M; Knecht, Peter; Garrido, José Antonio; Zhang, Bingru; Kitzerow, Heinz

    2016-03-23

    Composites of DNA origami nanostructures dispersed in a lyotropic chromonic liquid crystal are studied by polarizing optical microscopy. The homogeneous aqueous dispersions can be uniformly aligned by confinement between two glass substrates, either parallel to the substrates owing to uniaxial rubbing or perpendicular to the substrates using ozonized graphene layers. These opportunities of uniform alignment may pave the way for tailored anisometric plasmonic DNA nanostructures to photonic materials. In addition, a decorated texture with nonuniform orientation is observed on substrates coated with pristine graphene. When the water is allowed to evaporate slowly, microscopic crystal needles appear, which are aligned along the local orientation of the director. This decoration method can be used for studying the local orientational order and the defects in chromonic liquid crystals.

  10. Highly aligned arrays of high aspect ratio barium titanate nanowires via hydrothermal synthesis

    SciTech Connect

    Bowland, Christopher C.; Zhou, Zhi; Malakooti, Mohammad H.; Sodano, Henry A.

    2015-06-01

    We report on the development of a hydrothermal synthesis procedure that results in the growth of highly aligned arrays of high aspect ratio barium titanate nanowires. Using a multiple step, scalable hydrothermal reaction, a textured titanium dioxide film is deposited on titanium foil upon which highly aligned nanowires are grown via homoepitaxy and converted to barium titanate. Scanning electron microscope images clearly illustrate the effect the textured film has on the degree of orientation of the nanowires. The alignment of nanowires is quantified by calculating the Herman's Orientation Factor, which reveals a 58% improvement in orientation as compared to growth in the absence of the textured film. The ferroelectric properties of barium titanate combined with the development of this scalable growth procedure provide a powerful route towards increasing the efficiency and performance of nanowire-based devices in future real-world applications such as sensing and power harvesting.

  11. DIDA: Distributed Indexing Dispatched Alignment

    PubMed Central

    Mohamadi, Hamid; Vandervalk, Benjamin P; Raymond, Anthony; Jackman, Shaun D; Chu, Justin; Breshears, Clay P; Birol, Inanc

    2015-01-01

    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. PMID:25923767

  12. Global Alignment System for Large Genomic Sequencing

    2002-03-01

    AVID is a global alignment system tailored for the alignment of large genomic sequences up to megabases in length. Features include the possibility of one sequence being in draft form, fast alignment, robustness and accuracy. The method is an anchor based alignment using maximal matches derived from suffix trees.

  13. Photosensitive Polymers for Liquid Crystal Alignment

    NASA Astrophysics Data System (ADS)

    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.

  14. Combining Multiple Pairwise Structure-based Alignments

    SciTech Connect

    2014-11-12

    CombAlign is a new Python code that generates a gapped, one-to-many, multiple structure-based sequence alignment(MSSA) given a set of pairwise structure-based alignments. In order to better define regions of similarity among related protein structures, it is useful to detect the residue-residue correspondences among a set of pairwise structure alignments. Few codes exist for constructing a one-to-many, multiple sequence alignment derived from a set of structure alignments, and we perceived a need for creating a new tool for combing pairwise structure alignments that would allow for insertion of gaps in the reference structure.

  15. Grain Alignment in Starless Cores

    NASA Astrophysics Data System (ADS)

    Jones, T. J.; Bagley, M.; Krejny, M.; Andersson, B.-G.; Bastien, P.

    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}V}˜ 48. We find that {{P}K}/{{τ }K} continues to decline with increasing AV with a power law slope of roughly -0.5. Examination of published submillimeter (submm) polarimetry of starless cores suggests that by {{A}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}V}˜ 20. A simple model relating the alignment efficiency to the optical depth into the cloud reproduces the observations well.

  16. Transformation and alignment in similarity.

    PubMed

    Hodgetts, Carl J; Hahn, Ulrike; Chater, Nick

    2009-10-01

    This paper contrasts two structural accounts of psychological similarity: structural alignment (SA) and Representational Distortion (RD). SA proposes that similarity is determined by how readily the structures of two objects can be brought into alignment; RD measures similarity by the complexity of the transformation that "distorts" one representation into the other. We assess RD by defining a simple coding scheme of psychological transformations for the experimental materials. In two experiments, this "concrete" version of RD provides compelling fits of the data and compares favourably with SA. Finally, stepping back from particular models, we argue that perceptual theory suggests that transformations and alignment processes should generally be viewed as complementary, in contrast to the current distinction in the literature. PMID:19720370

  17. Iterative most likely oriented point registration.

    PubMed

    Billings, Seth; Taylor, Russell

    2014-01-01

    A new algorithm for model based registration is presented that optimizes both position and surface normal information of the shapes being registered. This algorithm extends the popular Iterative Closest Point (ICP) algorithm by incorporating the surface orientation at each point into both the correspondence and registration phases of the algorithm. For the correspondence phase an efficient search strategy is derived which computes the most probable correspondences considering both position and orientation differences in the match. For the registration phase an efficient, closed-form solution provides the maximum likelihood rigid body alignment between the oriented point matches. Experiments by simulation using human femur data demonstrate that the proposed Iterative Most Likely Oriented Point (IMLOP) algorithm has a strong accuracy advantage over ICP and has increased ability to robustly identify a successful registration result.

  18. Were Greek temples oriented towards aurorae?

    NASA Astrophysics Data System (ADS)

    Liritzis, Ioannis; Vassiliou, Helen

    2006-02-01

    Two ancient Greek temples of Apollo at Bassae (Phigaleia, western Peloponnese, Greece), and Thermon at Aetolia, (Aetoloacarnania, western central Greece), have a north-south orientation of their main entrances. This is a rather rare alignment of temples in general and specifically of Apollo in classical Greece, where most of them have broadly an east-west orientation. Based on historical and mythological accounts, as well as astronomical orientation measurements, the northern direction orientation of these constructions may relate to the rare, albeit impressive, occurrence of aurorae borealis, the northern lights. These strong lights are attributed to god Apollo by the epithet ``hyperborean'', meaning to the northern lands. Attribution is supported by archaeomagnetic directional data accompanied by auroral occurrence during those times.

  19. Optimization of bicelle lipid composition and temperature for EPR spectroscopy of aligned membranes.

    PubMed

    McCaffrey, Jesse E; James, Zachary M; Thomas, David D

    2015-01-01

    We have optimized the magnetic alignment of phospholipid bilayered micelles (bicelles) for EPR spectroscopy, by varying lipid composition and temperature. Bicelles have been extensively used in NMR spectroscopy for several decades, in order to obtain aligned samples in a near-native membrane environment and take advantage of the intrinsic sensitivity of magnetic resonance to molecular orientation. Recently, bicelles have also seen increasing use in EPR, which offers superior sensitivity and orientational resolution. However, the low magnetic field strength (less than 1 T) of most conventional EPR spectrometers results in homogeneously oriented bicelles only at a temperature well above physiological. To optimize bicelle composition for magnetic alignment at reduced temperature, we prepared bicelles containing varying ratios of saturated (DMPC) and unsaturated (POPC) phospholipids, using EPR spectra of a spin-labeled fatty acid to assess alignment as a function of lipid composition and temperature. Spectral analysis showed that bicelles containing an equimolar mixture of DMPC and POPC homogeneously align at 298 K, 20 K lower than conventional DMPC-only bicelles. It is now possible to perform EPR studies of membrane protein structure and dynamics in well-aligned bicelles at physiological temperatures and below.

  20. Macroscopic Ensembles of Aligned Carbon Nanotubes in Bubble Imprints Studied by Polarized Raman Microscopy

    DOE PAGES

    Ushiba, Shota; Hoyt, Jordan; Masui, Kyoko; Kono, Junichiro; Kawata, Satoshi; Shoji, Satoru

    2014-01-01

    We study the alignment of single-wall carbon nanotubes (SWCNTs) in bubble imprints through polarized Raman microscopy. A hemispherical bubble containing SWCNTs is pressed against a glass substrate, resulting in an imprint of the bubble membrane with a coffee ring on the substrate. We find that macroscopic ensembles of aligned SWCNTs are obtained in the imprints, in which there are three patterns of orientations: (i) azimuthal alignment on the coffee ring, (ii) radial alignment at the edge of the membrane, and (iii) random orientation at the center of the membrane. We also find that the alignment of SWCNTs in the imprintsmore » can be manipulated by spinning bubbles. The orientation of SWCNTs on the coffee ring is directed radially, which is orthogonal to the case of unspun bubbles. This approach enables one to align SWCNTs in large quantities and in a short time, potentially opening up a wide range of CNT-based electronic and optical applications.« less

  1. Optimization of bicelle lipid composition and temperature for EPR spectroscopy of aligned membranes

    NASA Astrophysics Data System (ADS)

    McCaffrey, Jesse E.; James, Zachary M.; Thomas, David D.

    2015-01-01

    We have optimized the magnetic alignment of phospholipid bilayered micelles (bicelles) for EPR spectroscopy, by varying lipid composition and temperature. Bicelles have been extensively used in NMR spectroscopy for several decades, in order to obtain aligned samples in a near-native membrane environment and take advantage of the intrinsic sensitivity of magnetic resonance to molecular orientation. Recently, bicelles have also seen increasing use in EPR, which offers superior sensitivity and orientational resolution. However, the low magnetic field strength (less than 1 T) of most conventional EPR spectrometers results in homogeneously oriented bicelles only at a temperature well above physiological. To optimize bicelle composition for magnetic alignment at reduced temperature, we prepared bicelles containing varying ratios of saturated (DMPC) and unsaturated (POPC) phospholipids, using EPR spectra of a spin-labeled fatty acid to assess alignment as a function of lipid composition and temperature. Spectral analysis showed that bicelles containing an equimolar mixture of DMPC and POPC homogeneously align at 298 K, 20 K lower than conventional DMPC-only bicelles. It is now possible to perform EPR studies of membrane protein structure and dynamics in well-aligned bicelles at physiological temperatures and below.

  2. Optimization of bicelle lipid composition and temperature for EPR spectroscopy of aligned membranes.

    PubMed

    McCaffrey, Jesse E; James, Zachary M; Thomas, David D

    2015-01-01

    We have optimized the magnetic alignment of phospholipid bilayered micelles (bicelles) for EPR spectroscopy, by varying lipid composition and temperature. Bicelles have been extensively used in NMR spectroscopy for several decades, in order to obtain aligned samples in a near-native membrane environment and take advantage of the intrinsic sensitivity of magnetic resonance to molecular orientation. Recently, bicelles have also seen increasing use in EPR, which offers superior sensitivity and orientational resolution. However, the low magnetic field strength (less than 1 T) of most conventional EPR spectrometers results in homogeneously oriented bicelles only at a temperature well above physiological. To optimize bicelle composition for magnetic alignment at reduced temperature, we prepared bicelles containing varying ratios of saturated (DMPC) and unsaturated (POPC) phospholipids, using EPR spectra of a spin-labeled fatty acid to assess alignment as a function of lipid composition and temperature. Spectral analysis showed that bicelles containing an equimolar mixture of DMPC and POPC homogeneously align at 298 K, 20 K lower than conventional DMPC-only bicelles. It is now possible to perform EPR studies of membrane protein structure and dynamics in well-aligned bicelles at physiological temperatures and below. PMID:25514061

  3. Optimization of Bicelle Lipid Composition and Temperature for EPR Spectroscopy of Aligned Membranes

    PubMed Central

    McCaffrey, Jesse E.; James, Zachary M.; Thomas, David D.

    2014-01-01

    We have optimized the magnetic alignment of phospholipid bilayered micelles (bicelles) for EPR spectroscopy, by varying lipid composition and temperature. Bicelles have been extensively used in NMR spectroscopy for several decades, in order to obtain aligned samples in a near-native membrane environment and take advantage of the intrinsic sensitivity of magnetic resonance to molecular orientation. Recently, bicelles have also seen increasing use in EPR, which offers superior sensitivity and orientational resolution. However, the low magnetic field strength (less than 1 T) of most conventional EPR spectrometers results in homogeneously oriented bicelles only at a temperature well above physiological. To optimize bicelle composition for magnetic alignment at reduced temperature, we prepared bicelles containing varying ratios of saturated (DMPC) and unsaturated (POPC) phospholipids, using EPR spectra of a spin-labeled fatty acid to assess alignment as a function of lipid composition and temperature. Spectral analysis showed that bicelles containing an equimolar mixture of DMPC and POPC homogeneously align at 298 K, 20 K lower than conventional DMPC-only bicelles. It is now be possible to perform EPR studies of membrane protein structure and dynamics in well-aligned bicelles at physiological temperatures and below. PMID:25514061

  4. Mechanism of Calcite Co-Orientation in the Sea Urchin Tooth

    SciTech Connect

    Killian, Christopher; Metzler, Rebecca; Gong, Y. U. T.; Olson, Ian; Aizenberg, Joanna; Politi, Yael; Wilt, Fred; Scholl, Andreas; Young, Anthony; Doran, Andrew; Kunz, Martin; Tamura, Nobumichi; Coppersmith, Susan; Gilbert, P. U. P. A.

    2009-12-01

    Sea urchin teeth are remarkable and complex calcite structures, continuously growing at the forming end and self-sharpening at the mature grinding tip. The calcite (CaCO{sub 3}) crystals of tooth components, plates, fibers, and a high-Mg polycrystalline matrix, have highly co-oriented crystallographic axes. This ability to co-orient calcite in a mineralized structure is shared by all echinoderms. However, the physico-chemical mechanism by which calcite crystals become co-oriented in echinoderms remains enigmatic. Here, we show differences in calcite c-axis orientations in the tooth of the purple sea urchin (Strongylocentrotus purpuratus), using high-resolution X-ray photoelectron emission spectromicroscopy (X-PEEM) and microbeam X-ray diffraction ({mu}XRD). All plates share one crystal orientation, propagated through pillar bridges, while fibers and polycrystalline matrix share another orientation. Furthermore, in the forming end of the tooth, we observe that CaCO{sub 3} is present as amorphous calcium carbonate (ACC). We demonstrate that co-orientation of the nanoparticles in the polycrystalline matrix occurs via solid-state secondary nucleation, propagating out from the previously formed fibers and plates, into the amorphous precursor nanoparticles. Because amorphous precursors were observed in diverse biominerals, solid-state secondary nucleation is likely to be a general mechanism for the co-orientation of biomineral components in organisms from different phyla.

  5. B-MIC: An Ultrafast Three-Level Parallel Sequence Aligner Using MIC.

    PubMed

    Cui, Yingbo; Liao, Xiangke; Zhu, Xiaoqian; Wang, Bingqiang; Peng, Shaoliang

    2016-03-01

    Sequence alignment is the central process for sequence analysis, where mapping raw sequencing data to reference genome. The large amount of data generated by NGS is far beyond the process capabilities of existing alignment tools. Consequently, sequence alignment becomes the bottleneck of sequence analysis. Intensive computing power is required to address this challenge. Intel recently announced the MIC coprocessor, which can provide massive computing power. The Tianhe-2 is the world's fastest supercomputer now equipped with three MIC coprocessors each compute node. A key feature of sequence alignment is that different reads are independent. Considering this property, we proposed a MIC-oriented three-level parallelization strategy to speed up BWA, a widely used sequence alignment tool, and developed our ultrafast parallel sequence aligner: B-MIC. B-MIC contains three levels of parallelization: firstly, parallelization of data IO and reads alignment by a three-stage parallel pipeline; secondly, parallelization enabled by MIC coprocessor technology; thirdly, inter-node parallelization implemented by MPI. In this paper, we demonstrate that B-MIC outperforms BWA by a combination of those techniques using Inspur NF5280M server and the Tianhe-2 supercomputer. To the best of our knowledge, B-MIC is the first sequence alignment tool to run on Intel MIC and it can achieve more than fivefold speedup over the original BWA while maintaining the alignment precision.

  6. Computational studies of the x-ray scattering properties of laser aligned stilbene

    SciTech Connect

    Debnarova, Andrea; Techert, Simone; Schmatz, Stefan

    2011-02-07

    The enhancement of the x-ray scattering signal from partially aligned molecular samples is investigated. The alignment properties of the studied molecular system are modeled based on the method of laser alignment. With the advances in the area of laser alignment of molecules, the application of this sample manipulation technique promises a great potential for x-ray scattering measurements. Preferential alignment of molecules in an otherwise amorphous sample leads to constructive interference and thus increases the scattering intensity. This enhances the structural information encoded in the scattering images and enables improved resolution in studies of reaction dynamics, as in this work is shown for the example of the photo-isomerization of stilbene. We demonstrate that the scattering signal is strongly influenced by the alignment axis. Even the most basic one-dimensional alignment offers significant improvement compared to the structural information provided by a randomly oriented sample. Although the signal is sensitive to the uncertainty in the alignment angle, it offers encouraging results even at realistic alignment uncertainties.

  7. Factors Influencing Shear Alignment of Cylinder-Forming Block Copolymer Thin Films

    NASA Astrophysics Data System (ADS)

    Davis, Raleigh; Register, Richard; Chaikin, Paul

    2014-03-01

    Application of shear stress to block copolymers is known to preferentially orient the microdomains in the direction of applied shear. While this phenomenon has been well studied for bulk block copolymer systems, the use of shear stress to align microdomains in block copolymer thin films (typically one to several microdomain layers) is still an active area of research. Numerous experimental factors influence the ease with which orientation is achieved as well as the ultimate quality of alignment observed. The present work investigates several of these factors using a series of cylinder-forming poly(styrene)-poly(hexylmethacrylate) copolymers. Parameters studied include film thickness, block copolymer molecular weight and composition, substrate wetting conditions (controlled via grafted polymer brush layers of either polystyrene or polyhexylmethacrylate), and applied shear stress. Quality of alignment is assessed via atomic force microscopy and subsequent computation of an orientational order parameter and the density of defects in the microdomain lattice. The results are compared to a melting-recrystallization model, thus providing greater insight into the fundamental mechanisms and key parameters which control how microdomains order in response to shear. In general monolayers are observed to align more poorly than thicker films, though the influence of film thickness on orientation depends strongly on polymer composition. Alignment quality is ultimately limited by inherent fluctuations in the cylinder trajectories as well as the presence of isolated dislocations.

  8. Highly Aligned Poly(vinylidene fluoride-co-hexafluoro propylene) Nanofibers via Electrospinning Technique.

    PubMed

    Han, Tae-Hwan; Nirmala, R; Kim, Tae Woo; Navamathavan, R; Kim, Hak Yong; Park, Soo Jin

    2016-01-01

    We report on the simple way of obtaining aligned poly(vinylidiene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofibers by electrospinning process. The collector drum rotation speed was adjusted to prepare well aligned PVDF-HFP nanofibers. The degree of alignment and the orientation of PVDF-HFP nanofibers can be significantly altered by varying the speed of collector drum rotation. The resultant PVDF-HFP nanofibers were systematically characterized. From the scanning electron microscopy data, it was found that the electrospun PVDF-HFP nanofibers were formed with well-aligned nature. The X-ray diffraction results revealed that the electrospun PVDF-HFP nanofibers with β-phase can be formed by the increased collector drum rotation speed. Overall, the collector rotation speed during the electrospinning process plays an important role in obtaining well-aligned and improved characteristics of PVDF-HFP nanofibers. PMID:27398493

  9. A facile method to align carbon nanotubes on polymeric membrane substrate

    PubMed Central

    Zhao, Haiyang; Zhou, Zhijun; Dong, Hang; Zhang, Lin; Chen, Huanlin; Hou, Lian

    2013-01-01

    The alignment of carbon nanotubes (CNT) is the fundamental requirement to ensure their excellent functions but seems to be desolated in recent years. A facile method, hot-press combined with peel-off (HPPO), is introduced here, through which CNT can be successfully vertically aligned on the polymeric membrane substrate. Shear force and mechanical stretch are proposed to be the main forces to align the tubes perpendicular to the substrate surface during the peel-off process. The alignment of CNT keeps its orientation in a thin hybrid membrane by dip-coating cellulose acetate dope solution. It is expected that the stable alignment of CNT by HPPO would contribute to the realization of its potential applications. PMID:24326297

  10. A facile method to align carbon nanotubes on polymeric membrane substrate

    NASA Astrophysics Data System (ADS)

    Zhao, Haiyang; Zhou, Zhijun; Dong, Hang; Zhang, Lin; Chen, Huanlin; Hou, Lian

    2013-12-01

    The alignment of carbon nanotubes (CNT) is the fundamental requirement to ensure their excellent functions but seems to be desolated in recent years. A facile method, hot-press combined with peel-off (HPPO), is introduced here, through which CNT can be successfully vertically aligned on the polymeric membrane substrate. Shear force and mechanical stretch are proposed to be the main forces to align the tubes perpendicular to the substrate surface during the peel-off process. The alignment of CNT keeps its orientation in a thin hybrid membrane by dip-coating cellulose acetate dope solution. It is expected that the stable alignment of CNT by HPPO would contribute to the realization of its potential applications.

  11. Measurements of magnetic field alignment

    SciTech Connect

    Kuchnir, M.; Schmidt, E.E.

    1987-11-06

    The procedure for installing Superconducting Super Collider (SSC) dipoles in their respective cryostats involves aligning the average direction of their field with the vertical to an accuracy of 0.5 mrad. The equipment developed for carrying on these measurements is described and the measurements performed on the first few prototypes SSC magnets are presented. The field angle as a function of position in these 16.6 m long magnets is a characteristic of the individual magnet with possible feedback information to its manufacturing procedure. A comparison of this vertical alignment characteristic with a magnetic field intensity (by NMR) characteristic for one of the prototypes is also presented. 5 refs., 7 figs.

  12. Alignment Tool For Inertia Welding

    NASA Technical Reports Server (NTRS)

    Snyder, Gary L.

    1991-01-01

    Compact, easy-to-use tool aligns drive bar of inertia welder over hole in stub. Ensures drive bar concentric to hole within 0.002 in. (0.051 mm.). Holds two batteries and light bulb. Electrical circuit completed, providing current to bulb when pin in contact with post. When pin centered in post hole, it does not touch post, and lamp turns off. Built for use in making repair welds on liquid-oxygen-injector posts in Space Shuttle main engine. Version having suitably modified dimensions used to facilitate alignment in other forests of post.

  13. XUV ionization of aligned molecules

    NASA Astrophysics Data System (ADS)

    Kelkensberg, F.; Rouzée, A.; Siu, W.; Gademann, G.; Johnsson, P.; Lucchini, M.; Lucchese, R. R.; Vrakking, M. J. J.

    2011-11-01

    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 CO2 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.

  14. XUV ionization of aligned molecules

    SciTech Connect

    Kelkensberg, F.; Siu, W.; Gademann, G.; Rouzee, A.; Vrakking, M. J. J.; Johnsson, P.; Lucchini, M.; Lucchese, R. R.

    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.

  15. The alignment-distribution graph

    NASA Technical Reports Server (NTRS)

    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.

  16. The alignment-distribution graph

    NASA Technical Reports Server (NTRS)

    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.

  17. Epitaxial growth of aligned AlGalnN nanowires by metal-organic chemical vapor deposition

    DOEpatents

    Han, Jung; Su, Jie

    2008-08-05

    Highly ordered and aligned epitaxy of III-Nitride nanowires is demonstrated in this work. <1010> M-axis is identified as a preferential nanowire growth direction through a detailed study of GaN/AlN trunk/branch nanostructures by transmission electron microscopy. Crystallographic selectivity can be used to achieve spatial and orientational control of nanowire growth. Vertically aligned (Al)GaN nanowires are prepared on M-plane AlN substrates. Horizontally ordered nanowires, extending from the M-plane sidewalls of GaN hexagonal mesas or islands demonstrate new opportunities for self-aligned nanowire devices, interconnects, and networks.

  18. Liquid crystal surface alignments by using ion beam sputtered magnetic thin films

    SciTech Connect

    Wu, H.-Y.; Pan, R.-P.

    2007-08-13

    A method for liquid crystal surface alignment by using a one-step, ion beam bombardment of the glass substrates is demonstrated. Precoating by polyimide is not necessary. The authors show that the homeotropic alignment is achieved due to orientation of the diamagnetic nematogenic molecules by the magnetic field from the {gamma}-Fe{sub 2}O{sub 3} ferrimagnetic thin films created on the substrates by ion beam bombardment. The film exhibits a high Curie temperature well above 300 K and a compensation temperature which is the typical feature of ferrimagnetism. This is a simple, noncontact, and reliable alignment method for liquid crystal devices.

  19. A Highly Permeable Aligned Montmorillonite Mixed-Matrix Membrane for CO2 Separation.

    PubMed

    Qiao, Zhihua; Zhao, Song; Wang, Jixiao; Wang, Shichang; Wang, Zhi; Guiver, Michael D

    2016-08-01

    Highly permeable montmorillonite layers bonded and aligned with the chain stretching orientation of polyvinylamineacid are immobilized onto a porous polysulfone substrate to fabricate aligned montmorillonite/polysulfone mixed-matrix membranes for CO2 separation. High-speed gas-transport channels are formed by the aligned interlayer gaps of the modified montmorillonite, through which CO2 transport primarily occurs. High CO2 permeance of about 800 GPU is achieved combined with a high mixed-gas selectivity for CO2 that is stable over a period of 600 h and independent of the water content in the feed.

  20. A Highly Permeable Aligned Montmorillonite Mixed-Matrix Membrane for CO2 Separation.

    PubMed

    Qiao, Zhihua; Zhao, Song; Wang, Jixiao; Wang, Shichang; Wang, Zhi; Guiver, Michael D

    2016-08-01

    Highly permeable montmorillonite layers bonded and aligned with the chain stretching orientation of polyvinylamineacid are immobilized onto a porous polysulfone substrate to fabricate aligned montmorillonite/polysulfone mixed-matrix membranes for CO2 separation. High-speed gas-transport channels are formed by the aligned interlayer gaps of the modified montmorillonite, through which CO2 transport primarily occurs. High CO2 permeance of about 800 GPU is achieved combined with a high mixed-gas selectivity for CO2 that is stable over a period of 600 h and independent of the water content in the feed. PMID:27312314

  1. Steering epitaxial alignment of Au, Pd, and AuPd nanowire arrays by atom flux change.

    PubMed

    Yoo, Youngdong; Seo, Kwanyong; Han, Sol; Varadwaj, Kumar S K; Kim, Hyun You; Ryu, Ji Hoon; Lee, Hyuck Mo; Ahn, Jae Pyoung; Ihee, Hyotcherl; Kim, Bongsoo

    2010-02-10

    We have synthesized epitaxial Au, Pd, and AuPd nanowire arrays in vertical or horizontal alignment on a c-cut sapphire substrate. We show that the vertical and horizontal nanowire arrays grow from half-octahedral seeds by the correlations of the geometry and orientation of seed crystals with those of as-grown nanowires. The alignment of nanowires can be steered by changing the atom flux. At low atom deposition flux vertical nanowires grow, while at high atom flux horizontal nanowires grow. Similar vertical/horizontal epitaxial growth is also demonstrated on SrTiO(3) substrates. This orientation-steering mechanism is visualized by molecular dynamics simulations.

  2. Uniformly oriented gramicidin channels embedded in thick monodomain lecithin multilayers.

    PubMed Central

    Huang, H W; Olah, G A

    1987-01-01

    Phosphatidylcholine multilayers, containing 20% water by total sample weight and gramicidin/lipid molar ratios up to 1:40 were aligned by low temperature annealing (less than 60 degrees C) and mechanical stressing. We were able to obtain large (greater than 80 micron thick X 40 mm2 area) monodomain defect-free multilayers containing approximately 10(17) uniformly oriented gramicidin channels. The alignment of lipid multilayers was monitored by conoscopy and polarized microscopy. The smectic defects, which appeared during the alignment process, were identified and dissolved. The incorporation of gramicidin into the multilayers in the form of transmembrane channels was indicated by its circular dichroic (CD) spectrum. A well-defined CD spectrum of uniformly oriented gramicidin channels was obtained. The oriented samples will allow spectroscopic studies of the ion channel in its conducting state and diffraction studies of the channel-channel organization in the membrane. Images FIGURE 1 PMID:2440487

  3. Nanostructured carbon films with oriented graphitic planes

    SciTech Connect

    Teo, E. H. T.; Kalish, R.; Kulik, J.; Kauffmann, Y.; Lifshitz, Y.

    2011-03-21

    Nanostructured carbon films with oriented graphitic planes can be deposited by applying energetic carbon bombardment. The present work shows the possibility of structuring graphitic planes perpendicular to the substrate in following two distinct ways: (i) applying sufficiently large carbon energies for deposition at room temperature (E>10 keV), (ii) utilizing much lower energies for deposition at elevated substrate temperatures (T>200 deg. C). High resolution transmission electron microscopy is used to probe the graphitic planes. The alignment achieved at elevated temperatures does not depend on the deposition angle. The data provides insight into the mechanisms leading to the growth of oriented graphitic planes under different conditions.

  4. Orientation distribution of microlites in obsidian

    NASA Astrophysics Data System (ADS)

    Manga, Michael

    1998-11-01

    The shape and three-dimensional orientation distribution of microlites are measured in obsidian from Little Glass Mountain, CA. Measurements are made from thin sections using an image series of high magnification digital micrographs taken serially through different focal depths. These measurements agree well with the theoretically predicted and experimentally measured distribution of long slender rods in a Newtonian fluid undergoing simple shear flow. In this type of flow, rods in a dilute suspension rotate periodically, spending most of the time aligned with the flow. Measurements of the detailed orientation distribution integrated with theoretical models provide a tool for inferring flow dynamics and the timing of magmatic processes.

  5. Orientation of churches by magnetic compasses?

    NASA Astrophysics Data System (ADS)

    Arneitz, Patrick; Draxler, Andrea; Rauch, Roman; Leonhardt, Roman

    2014-07-01

    In Christian religion the sunrise is of great symbolic importance. Therefore, many churches constructed in the Middle Ages point towards geographic East. Although `easting' of churches actually refers to the alignment towards the azimuth of sunrise on the individual churches' patron's day, deviation of nave alignment from the geographic East direction is often assumed to be caused by the use of magnetic compasses. Therefore, the church alignment could provide information about historical magnetic declination. We investigate 124 churches in Lower Austria and 68 in northern Germany to clarify this question as well as the `easting' hypothesis. Church orientations are determined from georeferenced satellite images. Metadata such as the construction year, possible reconstructions and the church patron are gathered to determine the date when current church direction was appointed, and to perform sunrise calculations. However, due to uncertainties of construction years and the declining importance of orientation tradition after the 15th century several churches are excluded from the study. Thus, 32 churches with reliable metadata remain for evaluation in each region. The analysis reveals a preferred alignment of naves towards geographic East in Lower Austria and northern Germany. The construction and alignment of churches was often affected by the pre-existing buildings and streets or topography and natural surroundings. Therefore, deviations from geographic East are more likely caused by town or landscape. The mean deviations from magnetic East in both regions are large compared to the mean deviations from geographic East and sunrise azimuths. Hence, the use of compasses cannot be confirmed. Despite a few churches indicating orientation according to their patron's day, a general trend cannot be observed in the data reviewed.

  6. Light-Driven Reversible Alignment Switching of Liquid Crystals Enabled by Azo Thiol Grafted Gold Nanoparticles.

    PubMed

    Xue, Chenming; Xiang, Jie; Nemati, Hossein; Bisoyi, Hari Krishna; Gutierrez-Cuevas, Karla; Wang, Ling; Gao, Min; Zhou, Shuang; Yang, Deng-ke; Lavrentovich, Oleg D; Urbas, Augustine; Li, Quan

    2015-06-22

    Stimuli-directed alignment control of liquid crystals (LCs) with desired molecular orientation is currently in the limelight for the development of smart functional materials and devices. Here, photoresponsive azo thiol (AzoSH) was grafted onto gold nanoparticles (GNPs). The resulting hybrid GNPs were able to homogeneously mix with a commercially available nematic LC host, as evidenced by Cryo-TEM. Interestingly, the LC nanocomposites were found to undergo reversible alignment transition upon light irradiation as a consequence of the trans-cis photoisomerization of the azo groups on the GNP surface. LC molecules in either planar or bare glass cells were able to change their alignment to vertical upon UV irradiation, while the vertically aligned LC molecules returned to the planar or random orientation under visible irradiation. Neither the azo thiol molecules nor the unfunctionalized GNPs alone promoted the alignment of the LC molecules in the system upon light irradiation. The photoinduced vertical alignment without applied electric or magnetic field was very stable over time and with respect to temperature. Furthermore, an optically switchable device based on the photostimulated reversible alignment control of LCs was demonstrated. PMID:26097118

  7. Single molecule spectroscopy of conjugated polymer chains in an electric field-aligned liquid crystal.

    PubMed

    Chang, Wei-Shun; Link, Stephan; Yethiraj, Arun; Barbara, Paul F

    2008-01-17

    Using single molecule polarization spectroscopy, we investigated the alignment of a polymer solute with respect to the liquid crystal (LC) director in an LC device while applying an external electric field. The polymer solute is poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (or MEH-PPV), and the LC solvent is 5CB. The electric field induces a change in the LC director orientation from a planar alignment (no electric field) to a perpendicular (homeotropic) alignment with an applied field of 5.5 x 103 V/cm. We find that the polymer chains align with the LC director in both planar and homeotropic alignment when measured in the bulk of the LC solution away from the device interface. Single molecule polarization distributions measured as a function of distance from the LC device interface reveal a continuous change of the MEH-PPV alignment from planar to homeotropic. The observed polarization distributions are modeled using a conventional elastic model that predicts the depth profile of the LC director orientation for the applied electric field. The excellent agreement between experiment and simulations shows that the alignment of MEH-PPV follows the LC director throughout the LC sample. Furthermore, our results suggest that conjugated polymers such as MEH-PPV can be used as sensitive local probes to explore complex (and unknown) structures in anisotropic media. PMID:17975912

  8. Comprehensive assessment of automatic structural alignment against a manual standard, the scop classification of proteins.

    PubMed Central

    Gerstein, M.; Levitt, M.

    1998-01-01

    We apply a simple method for aligning protein sequences on the basis of a 3D structure, on a large scale, to the proteins in the scop classification of fold families. This allows us to assess, understand, and improve our automatic method against an objective, manually derived standard, a type of comprehensive evaluation that has not yet been possible for other structural alignment algorithms. Our basic approach directly matches the backbones of two structures, using repeated cycles of dynamic programming and least-squares fitting to determine an alignment minimizing coordinate difference. Because of simplicity, our method can be readily modified to take into account additional features of protein structure such as the orientation of side chains or the location-dependent cost of opening a gap. Our basic method, augmented by such modifications, can find reasonable alignments for all but 1.5% of the known structural similarities in scop, i.e., all but 32 of the 2,107 superfamily pairs. We discuss the specific protein structural features that make these 32 pairs so difficult to align and show how our procedure effectively partitions the relationships in scop into different categories, depending on what aspects of protein structure are involved (e.g., depending on whether or not consideration of side-chain orientation is necessary for proper alignment). We also show how our pairwise alignment procedure can be extended to generate a multiple alignment for a group of related structures. We have compared these alignments in detail with corresponding manual ones culled from the literature. We find good agreement (to within 95% for the core regions), and detailed comparison highlights how particular protein structural features (such as certain strands) are problematical to align, giving somewhat ambiguous results. With these improvements and systematic tests, our procedure should be useful for the development of scop and the future classification of protein folds. PMID

  9. Alignment and Load Transfer in Carbon Nanotube and Dicyclopentadiene Composites

    NASA Astrophysics Data System (ADS)

    Severino, Joseph Vincent

    Individual carbon nanotubes (CNTs) are the strongest materials available but their macroscopic assemblies are weak. This work establishes a new thermosetting dicyclopentadiene (DCPD) and CNT composite that increases the strength of CNT assemblies. These high volume fraction and void free structures constitute advanced materials that could one day replace traditional composite systems. To further the understanding of physical interactions between polymer and CNTs, a novel "capstan" load transfer mechanism is also introduced. Self-supporting assemblies of interconnected carbon nanotubes were stretched, twisted and compressed to fashion composites by the infusion and polymerization of low viscosity DCPD based monomeric resins. The properties of the CNTs, polymer and composite were characterized with thermal gravimetric analysis (TGA), dynamic mechanical analysis (DMA) and Raman spectroscopy. The microstructure was analyzed by wide angle X-ray scattering (WAXS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Sheets were drawn at 15 m/min from a growth furnace to impart alignment then stretched to further modify alignment. The mechanical properties were determined in five orientations with respect to the growth direction. The strength was nearly three times higher along this growth direction than it was perpendicular, and modulus was nearly six times higher. Transverse stretching achieved 1.5 times the elongation but alignment was inferior due to CNT kinking that prevented alignment and consolidation. Composites yarns and sheets were investigated for the mechanical properties, microstructure and load transfer. The DCPD resin was found to wet the CNTs and lubricated deformation. This reduced loads during processing, and curing solidified the aligned and consolidated structure. The stretched and twisted composite yarns increased the failure stress 51%. In aligned composite sheet, the failure stress increased 200%. The increased stresses

  10. A near-Infrared SETI Experiment: Alignment and Astrometric precision

    NASA Astrophysics Data System (ADS)

    Duenas, Andres; Maire, Jerome; Wright, Shelley; Drake, Frank D.; Marcy, Geoffrey W.; Siemion, Andrew; Stone, Remington P. S.; Tallis, Melisa; Treffers, Richard R.; Werthimer, Dan

    2016-06-01

    Beginning in March 2015, a Near-InfraRed Optical SETI (NIROSETI) instrument aiming to search for fast nanosecond laser pulses, has been commissioned on the Nickel 1m-telescope at Lick Observatory. The NIROSETI instrument makes use of an optical guide camera, SONY ICX694 CCD from PointGrey, to align our selected sources into two 200µm near-infrared Avalanche Photo Diodes (APD) with a field-of-view of 2.5"x2.5" each. These APD detectors operate at very fast bandwidths and are able to detect pulse widths extending down into the nanosecond range. Aligning sources onto these relatively small detectors requires characterizing the guide camera plate scale, static optical distortion solution, and relative orientation with respect to the APD detectors. We determined the guide camera plate scale as 55.9+- 2.7 milli-arcseconds/pixel and magnitude limit of 18.15mag (+1.07/-0.58) in V-band. We will present the full distortion solution of the guide camera, orientation, and our alignment method between the camera and the two APDs, and will discuss target selection within the NIROSETI observational campaign, including coordination with Breakthrough Listen.

  11. Mechanically Oriented, Low-Curie-Temperature Materials

    NASA Technical Reports Server (NTRS)

    Boltich, Edward B.

    1991-01-01

    Proposed fabrication process produces permanent magnets of greater flux density, intended for use at temperatures far below room temperature. Such magnets parts of electrical motors and other electromechanical actuators operating in cryogenic systems. Performances of actuators increase with flux densities available from their magnets. Based on use of mechanical metallurgical techniques to make oriented magnets of Dy3Al2, because these techniques produce alignments above Curie temperature.

  12. Directional Freezing of Nanocellulose Dispersions Aligns the Rod-Like Particles and Produces Low-Density and Robust Particle Networks.

    PubMed

    Munier, Pierre; Gordeyeva, Korneliya; Bergström, Lennart; Fall, Andreas B

    2016-05-01

    We show that unidirectional freezing of nanocellulose dispersions produces cellular foams with high alignment of the rod-like nanoparticles in the freezing direction. Quantification of the alignment in the long direction of the tubular pores with X-ray diffraction shows high orientation of cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC) at particle concentrations above 0.2 wt % (CNC) and 0.08 wt % (CNF). Aggregation of CNF by pH decrease or addition of salt significantly reduces the particle orientation; in contrast, exceeding the concentration where particles gel by mobility constraints had a relatively small effect on the orientation. The dense nanocellulose network formed by directional freezing was sufficiently strong to resist melting. The formed hydrogels were birefringent and displayed anisotropic laser diffraction patterns, suggesting preserved nanocellulose alignment and cellular structure. Nondirectional freezing of the hydrogels followed by sublimation generates foams with a pore structure and nanocellulose alignment resembling the structure of the initial directional freezing.

  13. Directional Freezing of Nanocellulose Dispersions Aligns the Rod-Like Particles and Produces Low-Density and Robust Particle Networks.

    PubMed

    Munier, Pierre; Gordeyeva, Korneliya; Bergström, Lennart; Fall, Andreas B

    2016-05-01

    We show that unidirectional freezing of nanocellulose dispersions produces cellular foams with high alignment of the rod-like nanoparticles in the freezing direction. Quantification of the alignment in the long direction of the tubular pores with X-ray diffraction shows high orientation of cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC) at particle concentrations above 0.2 wt % (CNC) and 0.08 wt % (CNF). Aggregation of CNF by pH decrease or addition of salt significantly reduces the particle orientation; in contrast, exceeding the concentration where particles gel by mobility constraints had a relatively small effect on the orientation. The dense nanocellulose network formed by directional freezing was sufficiently strong to resist melting. The formed hydrogels were birefringent and displayed anisotropic laser diffraction patterns, suggesting preserved nanocellulose alignment and cellular structure. Nondirectional freezing of the hydrogels followed by sublimation generates foams with a pore structure and nanocellulose alignment resembling the structure of the initial directional freezing. PMID:27071304

  14. Aligning Assessments for COSMA Accreditation

    ERIC Educational Resources Information Center

    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…

  15. Aligned natural inflation with modulations

    NASA Astrophysics Data System (ADS)

    Choi, Kiwoon; Kim, Hyungjin

    2016-08-01

    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. Laser-Beam-Alignment Controller

    NASA Technical Reports Server (NTRS)

    Krasowski, M. J.; Dickens, D. E.

    1995-01-01

    In laser-beam-alignment controller, images from video camera compared to reference patterns by fuzzy-logic pattern comparator. Results processed by fuzzy-logic microcontroller, which sends control signals to motor driver adjusting lens and pinhole in spatial filter.

  17. Tonal Alignment in Irish Dialects

    ERIC Educational Resources Information Center

    Dalton, Martha; Ni Chasaide, Ailbhe

    2005-01-01

    A comparison of the contour alignment of nuclear and initial prenuclear accents was carried out for the Irish dialects of Gaoth Dobhair in Ulster (GD-U) and Cois Fharraige in Connaught (CF-C). This was done across conditions where the number of unstressed syllables following the nuclear and preceding the initial prenuclear accents was varied from…

  18. Methods to temporally align gait cycle data.

    PubMed

    Helwig, Nathaniel E; Hong, Sungjin; Hsiao-Wecksler, Elizabeth T; Polk, John D

    2011-02-01

    The need for the temporal alignment of gait cycle data is well known; however, there is little consensus concerning which alignment method to use. In this paper, we discuss the pros and cons of some methods commonly applied to temporally align gait cycle data (normalization to percent gait cycle, dynamic time warping, derivative dynamic time warping, and piecewise alignment methods). In addition, we empirically evaluate these different methods' abilities to produce successful temporal alignment when mapping a test gait cycle trajectory to a target trajectory. We demonstrate that piecewise temporal alignment techniques outperform other commonly used alignment methods (normalization to percent gait cycle, dynamic time warping, and derivative dynamic time warping) in typical biomechanical and clinical alignment tasks. Lastly, we present an example of how these piecewise alignment techniques make it possible to separately examine intensity and temporal differences between gait cycle data throughout the entire gait cycle, which can provide greater insight into the complexities of movement patterns.

  19. Resolution-adaptive face alignment with head pose correction

    NASA Astrophysics Data System (ADS)

    Zhang, Lu; Allebach, Jan; Lin, Qian; Wang, Xianwang

    2015-03-01

    Faces often appear very small and oriented in surveillance videos because of the need of wide fields of view and typically a large distance between the cameras and the scene. Both low resolution and side-view faces make tasks such as face recognition difficult. As a result, face hallucination or super-resolution techniques of face images are generally needed, which has become a thriving research field. However, most existing methods assume face images have been well aligned into some canonical form (i.e. frontal, symmetric). Therefore, face alignment, especially for low-resolution face images, is a key and first step to the success of many face applications. In this paper, we propose an auto alignment approach for face images at different resolution, which consist of two fundamental steps: 1) To find the locations of facial landmarks or feature points (i.e. eyes, nose, and etc.) even for very low resolution faces; 2) To estimate and correct head poses based on the landmark locations and a 3D reference face model. The effectiveness of this method is shown by the aligned face images and the improved face recognition score on released data sets.

  20. Collective alignment of nanorods in thin Newtonian films

    NASA Astrophysics Data System (ADS)

    Gu, Yu; Burtovyy, Ruslan; Townsend, James; Owens, Jeffery; Luzinov, Igor; Kornev, Konstantin

    2013-11-01

    We provide a complete analytical description of the alignment kinetics of magnetic nanorods in magnetic field. Nickel nanorods were formed by template electrochemical deposition in alumina membranes from a dispersion in a water-glycerol mixture. To ensure uniformity of the dispersion, the surface of the nickel nanorods was covered with polyvinylpyrrolidone (PVP). A 40-70 nm coating prevented aggregation of nanoroda. These modifications allowed us to control alignment of the nanorods in a magnetic field and test the proposed theory. An orientational distribution function of nanorods was introduced. We demonstrated that the 0.04% volume fraction of nanorods in the glycerol-water mixture behaves as a system of non-interacting particles. However, the kinetics of alignment of a nanorod assembly does not follow the predictions of the single-nanorod theory. The distribution function theory explains the kinetics of alignment of a nanorod assembly and shows the significance of the initial distribution of nanorods in the film. It can be used to develop an experimental protocol for controlled ordering of magnetic nanorods in thin films. This work was supported by the Air Force Office of Scientific Research, Grant numbers FA9550-12-1-0459 and FA8650-09-D-507 5900.