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Sample records for crystal sc materials

  1. Crystal Growth and Properties of Co2+ doped Y3Sc2Ga3O12 Single Crystal

    Institute of Scientific and Technical Information of China (English)

    Guo Shiyi; Yuan Duorong; Shi Xuzhong; Cheng Xiufeng; Zhang Xiqing; Yu Fapeng

    2007-01-01

    Single crystal of cobalt (Co)-doped Y3Sc2Ga3O12 (YSGG) with the dimensions up to φ20×40mm3 and undoped YSGG crystal with the dimensions up to φ28×60mm3 have been grown using the Czochralski technique. The structure of the crystal was characterized by the X-ray powder diffraction (XRPD) method. The absorbance spectra of the crystal shows that it has strong absorption bands at 606 and 1540nm. The results indicate that the crystal Y3Sc2Ga3O12 may be a kind of good Q-switch material.

  2. The new single crystal diffractometer SC3

    Energy Technology Data Exchange (ETDEWEB)

    Schefer, J.; Koch, M.; Keller, P.; Fischer, S.; Thut, R. [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    Single crystal diffraction is a powerful method for the determination of precise structure parameters, superlattices, stress. Neutron single crystal diffraction gives additionally to X-rays information on magnetic structures, both commensurate and incommensurate, hydrogen positions, hydrogen bonding behavior and accurate bondlengths, e.g. important in cuprates. The method is therefore especially powerful if combined with X-ray diffraction results. The new instrument at SINQ has been designed for inorganic materials and is positioned at a thermal beam tube, pointing on a water scatterer. This scatterer is presently operating with H{sub 2}O at ambient temperature, but a change to another medium at different temperature is possible. The instrument will be equipped with three area detectors, moving at fixed difference in 2{Theta}. each detector may be individually moved around a vertical circle (tilting angle {gamma}), allowing to use not only 4-circle geometry in the temperature range from 1.5 to 380 K, but also any equipment from a dilution refrigerator (7 mK) to a heavy magnet. A high temperature furnace for 4-circle geometry is foreseen as a future option. (author) 6 figs., 1 tab., 7 refs.

  3. Lanthanide-doped NaScF4 nanoprobes: crystal structure, optical spectroscopy and biodetection

    Science.gov (United States)

    Ai, Yu; Tu, Datao; Zheng, Wei; Liu, Yongsheng; Kong, Jintao; Hu, Ping; Chen, Zhuo; Huang, Mingdong; Chen, Xueyuan

    2013-06-01

    Trivalent lanthanide ions (Ln3+)-doped inorganic nanoparticles (NPs) as potential luminescent bioprobes have been attracting tremendous interest because of their unique upconversion (UC) and downconversion (DC) luminescence properties. NaScF4, as an important host material, has been rarely reported and its crystal structure remains unclear. Herein, based on the single crystal X-ray diffraction, the space group of NaScF4 crystals was determined to be P31 containing multiple sites of Sc3+ with crystallographic site symmetry of C1, which was verified by high-resolution photoluminescence spectroscopy of Eu3+ at low temperature (10 K). Furthermore, monodisperse and size-controllable NaScF4:Ln3+ NPs were synthesized via a facile thermal decomposition method. The biotinylated NaScF4:Er3+/Yb3+ NPs were demonstrated for their applications as a heterogeneous UC luminescence bioprobe to detect avidin with a detection limit of 180 pM. After bioconjugation with amino-terminal fragment (ATF) of urokinase plasminogen activator (uPA), NaScF4:Ln3+ NPs also exhibited specific recognition of cancer cells overexpressed with uPA receptor (uPAR, an important marker of tumor biology and metastasis), showing great potentials in tumor-targeted bioimaging.Trivalent lanthanide ions (Ln3+)-doped inorganic nanoparticles (NPs) as potential luminescent bioprobes have been attracting tremendous interest because of their unique upconversion (UC) and downconversion (DC) luminescence properties. NaScF4, as an important host material, has been rarely reported and its crystal structure remains unclear. Herein, based on the single crystal X-ray diffraction, the space group of NaScF4 crystals was determined to be P31 containing multiple sites of Sc3+ with crystallographic site symmetry of C1, which was verified by high-resolution photoluminescence spectroscopy of Eu3+ at low temperature (10 K). Furthermore, monodisperse and size-controllable NaScF4:Ln3+ NPs were synthesized via a facile thermal

  4. Materials Characterization of High-Temperature Epoxy Resins: SC-79 and SC-15/SC-79 Blend

    Science.gov (United States)

    2011-03-01

    Army composite applications. SC-15 is a toughened commercial vacuum-assisted resin transfer molding ( VARTM ) resin produced by Applied Poleramic Inc...very well in VARTM processes and has good damage resistance in structural and ballistic applications. However, the relatively low glass transition...low-viscosity, two-phase toughened, cycloaliphatic amine–cured commercial VARTM resin system designed to be easy to handle and have a long processing

  5. Crystal fields of dilute Tb, Dy, or Er in Sc obtained by magnetization measurements

    DEFF Research Database (Denmark)

    Høg, J.; Touborg, P.

    1976-01-01

    Crystal-field parameters for dilute Sc-Tb, Sc-Dy, and Sc-Er alloys have been obtained by fitting theoretical expressions to the experimentally measured paramagnetic susceptibility. The initial susceptibility was measured and corrected for the effects of ordering at the lowest temperatures in the ...

  6. Ca- and Sc-based ternary AlB2-like crystals: a first-principles study

    Science.gov (United States)

    Tsetseris, Leonidas

    2017-02-01

    The aluminum diboride (AlB2) crystal structure comprises intercalated metal atoms between honeycomb sheets. In addition to metal diborides, which represent the most common family of AlB2-like structures, many more materials are known to crystallize in this geometry. Here we use first-principles calculations to probe the structural and electronic properties of several such systems. Specifically, we investigate the stability of various polymorphs of CaAuAs, CaAuP, CaCuP, ScAuGe, ScAuSi, Ca2AgSi3 and Ca2AuGe3 and find lattice parameters in excellent agreement with available experimental data. The analysis of densities of states and band structure diagrams show that all materials are metallic. However, the details of band dispersion vary significantly, from typical metals such as CaAuP, to almost semi-metallic behaviour in CaCuP.

  7. Evaluation of the difficulty of crystallization of organic compounds using the critical supersaturation ratio (Sc)

    Science.gov (United States)

    Nagamatsu, Daiki; Ida, Yasuo; Takiyama, Hiroshi

    2014-11-01

    In the case of solvent selection, supersolubility is an index for improving crystallization behavior. However, supersolubility is affected by kinetic factors such as the cooling rate. An index for suitable solvent selection is needed. The supersaturation ratio (S) is one of the operation design indices of controlling crystallization behavior such as supersolubility. The S at 298 K (S298) of the pharmaceutical compounds theophylline, noscapine, clotrimazole, indomethacin, carbamazepine, naproxene and tolbutamide were measured in ethanol using a polythermal method. If the compound had a large lnS298, the cooling rate strongly affected the temperature of the cloud point in the cooling crystallization method. In order to estimate the crystallization behavior without the cooling rate effect, the critical supersaturation ratio (Sc) was proposed. Sc at 298 K (Sc298) was calculated from dissolution/cloud points at 0 K/min extrapolated from that of several heating/cooling rates to remove the kinetic effects on S. The lnSc298 values of theophylline, noscapine and clotrimazole were estimated in acetonitrile, methyl ethyl ketone, tetrahydrofuran, ethyl acetate, methanol, ethanol and isopropanol. The lnSc298 value of clotrimazole was the largest in all solvents. The results showed that lnSc298 was a simple index which could be used to evaluate the crystallization behavior resulting from the interaction between the solvent and the compound. In conclusion, the proposed lnSc298 should be useful for comparing the difficulty of crystallization which indicates how we should obtain desired crystals within a certain finite time period for development API in the manufacturing field without considering the effect of the heating/cooling rate.

  8. Growth and Holographic Storage Properties of Sc, Fe Co-Doped Lithium Niobate Crystals

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The holographic storage properties of Fe (0.03% (mass fraction) Fe2O3):LiNbO3 doped with Sc at different levels (0, 1%, 2%, 3%) were investigated.The Sc threshold concentration in Fe:LiNbO3 was implied to be about 3%(mole fraction) because O-H vibration absorption peak of Sc (3%):Fe:LiNbO3 was at 3508 cm-1, compared with 3484 cm-1 of crystals with lower Sc doping level.Sc(3%):Fe:LiNbO3 exhibited higher optical damage resistance ability.The threshold intensity (wavelength 488 nm) of Sc (3%):Fe:LiNbO3 was 2.2×102 W·cm-2, two orders of magnitude higher than that of Fe:LiNbO3.Holographic storage properties of the crystals were determined in an extraordinary polarized laser of wavelength 632.8 nm by a two-wave coupling method.It was found that in terms of holographic storage properties, the optimal doping concentration of Sc was 2%(mole fraction) among this crystal series.

  9. Ultraviolet luminescence of ScPO4, AlPO4 and GaPO4 crystals.

    Science.gov (United States)

    Trukhin, Anatoly N; Shmits, Krishjanis; Jansons, Janis L; Boatner, Lynn A

    2013-09-25

    The luminescence of self-trapped excitons (STEs) was previously observed and described for the case of tetragonal-symmetry ScPO4 single crystals. The subject band in this material is situated in the UV spectral range of ∼210 nm or ∼5.8 eV. In the present work, we are both expanding this earlier luminescence study and seeking to identify similar luminescence phenomena in other orthophosphate crystals, i.e., AlPO4 and GaPO4. These efforts have proven to be successful--in spite of the structural differences between these materials and ScPO4. Specifically we have found that for AlPO4 and GaPO4, in addition to an α-quartz-like STE, there is a UV luminescence band that is similar in position and decay properties to that of ScPO4 crystals. Potentially this represents an STE in AlPO4 and GaPO4 crystals that is analogous to the STE of ScPO4 and other orthophosphates. The decay kinetics of the UV luminescence of ScPO4 was studied over a wide temperature range from 8 to 300 K, and they exhibited some unusual decay characteristics when subjected to pulses from an F2 excimer laser (157 nm). These features could be ascribed to a triplet state of the STE that is split in a zero magnetic field. A fast decay of the STE was detected as well, and therefore, we conclude that, in addition to the slow luminescence corresponding to a transition from the triplet state, there are singlet-singlet transitions of the STE. Time-resolved spectra of the slow and fast decay exhibit a small shift (∼0.15 eV) indicating that the singlet-triplet splitting is small and the corresponding wavefunction of the STE is widely distributed over the atoms of the ScPO4 crystal where the STE is created.

  10. Single crystal to single crystal (SC-to-SC) transformation from a nonporous to porous metal-organic framework and its application potential in gas adsorption and Suzuki coupling reaction through postmodification.

    Science.gov (United States)

    Sen, Rupam; Saha, Debraj; Koner, Subratanath; Brandão, Paula; Lin, Zhi

    2015-04-07

    A new amino-functionalized strontium-carboxylate-based metal-organic framework (MOF) has been synthesized that undergoes single crystal to single crystal (SC-to-SC) transformation upon desolvation. Both structures have been characterized by single-crystal X-ray analysis. The desolvated structure shows an interesting 3D porous structure with pendent -NH2 groups inside the pore wall, whereas the solvated compound possesses a nonporous structure with DMF molecules on the metal centers. The amino group was postmodified through Schiff base condensation by pyridine-2-carboxaldehyde and palladium was anchored on that site. The modified framework has been utilized for the Suzuki cross-coupling reaction. The compound shows high activity towards the C-C cross-coupling reaction with good yields and turnover frequencies. Gas adsorption studies showed that the desolvated compound had permanent porosity and was microporous in nature with a BET surface area of 2052 m(2)  g(-1). The material also possesses good CO2 (8 wt %) and H2 (1.87 wt %) adsorption capabilities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Validity evaluation of Sc x Al1-x N material constants based on SAW characteristics

    Science.gov (United States)

    Tang, Gongbin; Han, Tao; Zhang, Qiaozhen; Yamazaki, Kenta; Omori, Tatsuya; Hashimoto, Ken-ya

    2016-11-01

    This paper is aimed at examining the validity of material constants reported for use in surface acoustic wave (SAW) device simulations. First, based on the full set of material constants calculated by first principle, bulk acoustic wave velocities are calculated for Sc x Al1-x N and compared with published experimental results. Then, the effects of the Sc x Al1-x N material constants with different Sc content on acoustic characteristics are calculated and the influence of shear vibrations on SAW characteristics are recognized. Then, a series of SAW devices are fabricated on Sc x Al1-x N film/Si substrate structure with various Cu and ScAlN thicknesses h Cu and h ScAlN, respectively, and measured variations of phase velocity V and effective electromechanical coupling factor K\\text{e}2 with these parameters are compared with the calculation. The fairly well-agreed results indicate a reliable set of Sc x Al1-x N material constants for SAW device simulations.

  12. Preparation and Characterization of Gd3Sc2Ga3O12 Polycrystalline Material by Co-Precipitation Method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Gd3Sc2Ga3O12 polycrystalline material for single crystal growth was prepared with Ga, Gd2O3 and Sc2O3 as starting materials and aqueous ammonia as the precipitator by co-precipitation method. The precursors sintered at various temperatures were characterized by infrared spectra (IR), X-ray diffractometry (XRD) and transmitted electron microscopy (TEM). The results showed that pure GSGG phase could be obtained at 900 ℃. The sintered powders were well-dispersed and less-aggregated in the sintered temperature range of 900~1000 ℃. XRD and TEM show that the polycrystalline particle sizes of the polycrystalline powders were about 20~50 nm. Compared with the method that Ga2O3, Gd2O3 and Sc2O3 were mixed directly and sintered to get polycrystalline materials, the synthesized temperature was lower and sintered time was shorter. Thus co-precipitation was a good method to synthesize GSGG polycrystalline material.

  13. Melt growth, structure and properties of (ZrO2)1-x(Sc2O3)x solid solution crystals (x=0.035-0.11)

    Science.gov (United States)

    Borik, M. A.; Bredikhin, S. I.; Kulebyakin, A. V.; Kuritsyna, I. E.; Lomonova, E. E.; Milovich, F. O.; Myzina, V. A.; Osiko, V. V.; Panov, V. A.; Ryabochkina, P. A.; Seryakov, S. V.; Tabachkova, N. Yu.

    2016-06-01

    Crystals of (ZrO2)1-x(Sc2O3)x solid solutions with x=0.035, 0.06, 0.09 and 0.11 have been grown for the first time using the directional crystallization technique. Analysis of the scandium distribution along the crystal showed that the composition of all specimens is homogeneous, and the Sc2O3 concentration is almost identical to its content in the charge. All specimens exhibit a little decline in the scandium concentration along the crystal, this indicating that the effective distribution coefficient Sc is slightly greater than 1. The structure of as-grown crystals has been studied as a function of the Sc2O3 stabilising oxide concentration by X-ray diffraction, transmission electron microscopy and Raman spectroscopy. Crystals containing 3.5 mol% Sc2O3 are a mixture of the monoclinic and tetragonal phases, the crystals containing 6 mol% Sc2O3 have a tetragonal structure, those with 9 mol% Sc2O3 have the tetragonal phase with inclusions of the rhombohedral one and the specimens with 11 mol% Sc2O3 represent the rhombohedral phase with inclusions of the cubic phase. The electrical conductivity was measured as a function of temperature by electrochemical impedance spectroscopy. The conductivity of the scandia stabilized crystals, in spite of their inhomogeneity, presence of stresses and low fracture toughness, is comparable with that of the yttria stabilized zirconia crystals.

  14. Optical properties and radiation response of Ce{sup 3+}-doped GdScO{sub 3} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Yamaji, Akihiro; Fujimoto, Yutaka; Futami, Yoshisuke; Yokota, Yuui; Kurosawa, Shunsuke [Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Kochurikhin, Vladimir [General Physics Institute, 38 Vavilov Str., 119991 Moscow (Russian Federation); Yanagida, Takayuki [New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Yoshikawa, Akira [Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramaki, Aoba-ku, Sendai 980-8579 (Japan)

    2012-12-15

    10%-Ce doped GdScO{sub 3} perovskite type single crystal was grown by the Czochralski process. The Ce concentration in the crystal was measured. No impurity phases were observed by powder X-ray diffraction analysis. We evaluated the optical and radiation properties of the grown crystal. Ce:GdScO{sub 3} crystal showed photo- and radio-luminescence peaks due to Ce{sup 3+} of 5d-4f transition and colour centre. The photoluminescence decay time was sub-ns order. The relative light yield under 5.5 MeV alpha-ray excitation was calculated to be approximately 9% of BGO. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Thermography of semi-transparent materials by a FLIR ThermaCAM SC3000 infrared camera

    NARCIS (Netherlands)

    Van der Tempel, L.

    2011-01-01

    An acceptance test for thermography of semi-transparent materials by a FLIR ThermaCAM SC3000 infrared camera with 8.0 µm low-wavelength-pass filter has been developed and performed on polycarbonate, PEN, quartz, Corning 1737 glass, G427 cone glas, G443 screen glass, Schott Zerodur, silicon and a

  16. Thermography of semi-transparent materials by a FLIR ThermaCAM SC3000 infrared camera

    NARCIS (Netherlands)

    Van der Tempel, L.

    2011-01-01

    An acceptance test for thermography of semi-transparent materials by a FLIR ThermaCAM SC3000 infrared camera with 8.0 µm low-wavelength-pass filter has been developed and performed on polycarbonate, PEN, quartz, Corning 1737 glass, G427 cone glas, G443 screen glass, Schott Zerodur, silicon and a bl

  17. Influence of Sc3+ on LiMn2O4 cathode materials at elevated temperature

    Institute of Scientific and Technical Information of China (English)

    LIU Huiyong; DENG Ganqun; GUO Yonglang

    2008-01-01

    Sc3+-doped lithium manganese oxides were synthesized by solid-state reaction. The influences of doping element on structure,mean valence of manganese, and electrochemical performances were studied by X-ray diffraction (XRD), galvanostatic charge-discharge and cyclic voltammetric tests, and also electrochemical impedance spectroscopy (EIS). XRD tests showed that doped lithium manganese oxides were pure spinel structure without other phases. Redox titration and visible spectrophotometry tests indicated that the mean valence of man-ganese in doped lithium manganese oxides was higher than that of pure one. LiSc0.02Mn1.98O4 remained 92.9% of the initial specific discharge capacity after 50th cycle at a constant current of 50 m/g, and the reversibility of LiSc0.02Mn1.98O4 was improved in comparison with pure LiMn2O4 at 50 ℃. EIS indicated that film deposition on spinel particles was suppressed because of Sc3+ doping, and the charge transfer be-tween the surface film and spinel particles with increasing temperature for Sc3+-doped materials became easier as compared with undoped one.

  18. Growth and magnetic properties of MnCl2-4SC(NH2)2 single crystals

    Science.gov (United States)

    Shi, J.; Xu, H. S.; Chen, L. M.; Song, J. D.; Wu, J. C.; Liu, X. G.; Zhao, X.; Sun, X. F.

    2016-10-01

    NiCl2-4SC(NH2)2 (DTN) is a famous one-dimensional antiferromagnet with magnon Bose-Einstein condensation. In this work, single crystals of MnCl2-4SC(NH2)2 (DTM) with size up to (8-10)×(8-10)×(3-5) mm3 are grown by using the slow evaporation method with optimized conditions. The single crystals are characterized by measurements of X-ray diffraction, magnetic susceptibility, and specific heat. It is found that although DTM has a similar crystal structure to DTN, it shows a paramagnetic behavior. The reason for no spin exchange among Mn2+ ions can be understood in terms of the negligible overlap of the Mn2+-3d orbital and the neighboring Cl--3p orbital.

  19. Crystallization and preliminary X-ray diffraction analysis of the mitochondrial transcription factor sc-mtTFB from Saccharomyces cerevisiae.

    Science.gov (United States)

    Schubot, F D; Chen, C J; Rose, J P; Wang, B C

    2000-07-01

    Eukaryotic mitochondria contain a distinct mini-chromosome. In yeast, transcription of the mitochondrial genome is mediated by a nuclear-encoded RNA polymerase consisting of a single polypeptide core enzyme and a specificity factor termed sc-mtTFB which bears some similarity to bacterial sigma-factors. sc-mtTFB from Saccharomyces cerevisiae has been cloned, expressed, purified and crystallized. The crystals belong to the monoclinic space group C2, with unit-cell parameters a = 89.7, b = 44.6, c = 98.9 A, beta = 110 degrees. Based on one molecule per asymmetric unit, the solvent content is estimated to be 48%. Small crystals of dimensions 0.01 x 0.05 x 0.13 mm diffract to at least 2.7 A resolution on a rotating-anode X-ray source.

  20. Vibrational properties of Ca{sub 3}Sc{sub 2}Ge{sub 3}O{sub 12}, a garnet host crystal for laser applications

    Energy Technology Data Exchange (ETDEWEB)

    Cavalli, Enrico [Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica e Chimica Fisica, Universita di Parma, Parma (Italy)]. E-mail: cavalli@ipruniv.cce.unipr.it; Zannoni, Ester [Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica e Chimica Fisica, Universita di Parma, Parma (Italy); Bettinelli, Marco; Speghini, Adolfo [Dipartimento Scientifico e Tecnologico, Universita di Verona Ca Vignal, Verona (Italy); Tonelli, Mauro; Toncelli, Alessandra [INFM, Pisa (Italy); Dipartimento di Fisica, Universita di Pisa, Pisa (Italy)

    2000-05-29

    The IR and the Raman spectra of the Ca{sub 3}Sc{sub 2}Ge{sub 3}O{sub 12} (CaSGG) garnet crystal have been measured and discussed in terms of internal and external modes of the tetrahedral GeO{sup 4-}{sub 4} moiety. Some important aspects of the electronic spectroscopy of these materials activated with luminescent ions, i.e. the multiphonon relaxation of the excited states and the vibrational structure of the optical bands, have been taken into consideration, and correspondences with the vibrational properties of the host lattice have been presented. (author)

  1. Two-dimensional nanoscale correlations in the strong negative thermal expansion material ScF3

    Science.gov (United States)

    Handunkanda, Sahan U.; Occhialini, Connor A.; Said, Ayman H.; Hancock, Jason N.

    2016-12-01

    We present diffuse x-ray scattering data on the strong negative thermal expansion (NTE) material ScF3 and find that two-dimensional nanoscale correlations exist at momentum-space regions associated with possibly rigid rotations of the perovskite octahedra. We address the extent to which rigid octahedral motion describes the dynamical fluctuations behind NTE by generalizing a simple model supporting a single floppy mode that is often used to heuristically describe instances of NTE. We find this model has tendencies toward dynamic inhomogeneities and its application to recent and existing experimental data suggest an intricate link between the nanometer correlation length scale, the energy scale for octahedral tilt fluctuations, and the coefficient of thermal expansion in ScF3. We then investigate the breakdown of the rigid limit and propose a resolution to an outstanding debate concerning the role of molecular rigidity in strong NTE materials.

  2. Growth and Characterization of y-Nd3+: LaSc3(BO3)4 Crystal

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new laser crystal Nd005La0.95Sc3(BO3)4 up to 50mm×38mm×7 mn was grown by top-seeded solution growth method from a Li6B4O9 flux. The grown crystal was characterized by X-ray powder diffraction. Its crystal structure is monoclinic with space group Cc and the unit cell dimensions: a=12.066(5), b=9.864(2), c=7.740(3) A, β= 105.48(5)°, V=887.8(6)A3, Z=4, Dc=3.81g/cm3, which belongs to low-temperature phase. The optical absorption of the crystal shows that NLSB has a strong absorption band at 807.7 nm, which is suitable for laser-diode pumping.

  3. Structure of Non-stoichiometric Sr6Gd0.61Sc1.39(BO3)6 Crystal

    Institute of Scientific and Technical Information of China (English)

    HU Zu-Shu; LIN Zhou-Bin; CHEN Jiu-Tong; WANG Guo-Fu

    2004-01-01

    The crystal of the title compound Sr6Gd0.61Sc1.39(BO3)6 (Mr = 1037.00) was grown by Czochralski method. It crystallizes in trigonal, space group with a = 12.415(2), c = 9.274(2) (A。), Z = 3, V = 1238.0(4) (A。)3, Dc = 4.173 g/cm3, λ(MoKα) = 0.71073 (A。), μ = 22.278 mm-1, F(000) = 1411, S = 1.213, the final R = 0.0577 and wR = 0.1414 for 401 observed reflections with I>2σ(I). In the structure Gd(1)O6 Gd(1) = Gd0.46 + Sc0.54) and Gd(2)O6 (Gd(2)= Gd0.15 + Sc0.85) are alternately stacked between the planar triangular BO3 groups to form chains extending along the trigonal axis. These chains are connected through the 9-coordinate Sr atoms.

  4. Gallium Nitride Crystals: Novel Supercapacitor Electrode Materials.

    Science.gov (United States)

    Wang, Shouzhi; Zhang, Lei; Sun, Changlong; Shao, Yongliang; Wu, Yongzhong; Lv, Jiaxin; Hao, Xiaopeng

    2016-05-01

    A type of single-crystal gallium nitride mesoporous membrane is fabricated and its supercapacitor properties are demonstrated for the first time. The supercapacitors exhibit high-rate capability, stable cycling life at high rates, and ultrahigh power density. This study may expand the range of crystals as high-performance electrode materials in the field of energy storage.

  5. Synthetic thermoelectric materials comprising phononic crystals

    Science.gov (United States)

    El-Kady, Ihab F; Olsson, Roy H; Hopkins, Patrick; Reinke, Charles; Kim, Bongsang

    2013-08-13

    Synthetic thermoelectric materials comprising phononic crystals can simultaneously have a large Seebeck coefficient, high electrical conductivity, and low thermal conductivity. Such synthetic thermoelectric materials can enable improved thermoelectric devices, such as thermoelectric generators and coolers, with improved performance. Such synthetic thermoelectric materials and devices can be fabricated using techniques that are compatible with standard microelectronics.

  6. Charleston Harbor, SC, Regional Sediment Management Study; Beneficial Use of Dredged Material through Nearshore Placement

    Science.gov (United States)

    2017-05-01

    ER D C/ CH L TR -1 7- 7 Regional Sediment Management (RSM) Program Charleston Harbor, SC, Regional Sediment Management Study...acwc.sdp.sirsi.net/client/default. Regional Sediment Management (RSM) Program ERDC/CHL TR-17-7 May 2017 Charleston Harbor, SC, Regional Sediment...454632, “Charleston Harbor, SC; Regional Sediment Management Study” ERDC/CHL TR-17-7 ii Abstract The 2015 Charleston Harbor, SC, final

  7. Materials research at Stanford University. [composite materials, crystal structure, acoustics

    Science.gov (United States)

    1975-01-01

    Research activity related to the science of materials is described. The following areas are included: elastic and thermal properties of composite materials, acoustic waves and devices, amorphous materials, crystal structure, synthesis of metal-metal bonds, interactions of solids with solutions, electrochemistry, fatigue damage, superconductivity and molecular physics and phase transition kinetics.

  8. Estimation of low-temperature spectra behavior in Nd-doped Sc2SiO5 single crystal.

    Science.gov (United States)

    Zheng, Lihe; Xu, Jun; Su, Liangbi; Li, Hongjun; Wang, Qingguo; Ryba-Romanowski, Witold; Lisiecki, Radosław; Wu, Feng

    2009-11-15

    High optical quality Nd-doped Sc(2)SiO(5) crystal with size of diameter 27 mm x 60 mm was obtained by Czochralski method. An x-ray diffraction pattern of Nd:SSO crystal confirmed that the as-grown crystal was isostructual with the SSO crystal. Absorption and emission spectra were recorded at 10 K. The Judd-Ofelt theory was applied to obtain standard parameters Omega t(t=2,4,6) and the fitting result of experimental absorption line strengths, which provided the F3/24 radiative lifetime (tau(rad)) of 219 micros and the luminescence branching ratio beta of 0.57 for the (4)F(3/2)-(4)I(9/2) laser transition. The stimulated emission cross section of 1.04 x 10(-19) cm(2) at 1074 nm was calculated using the Füchtbauer-Ladenburg equation. The (4)F(3/2) luminescence lifetimes with 215 micros at 10 K and 198 micros at 300 K were determined from luminescence decay curves, indicating high quantum efficiency in the Nd:SSO crystal. All these results showed that Nd:SSO would be a promising gain media in solid-state lasers.

  9. Materials science: Crystals aligned through graphene

    Science.gov (United States)

    Lee, Minjoo Larry

    2017-04-01

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

  10. Crystal structure of triple oxides HO/sub 2/ScNbO/sub 7/ and Sm/sub 2/ScTaO/sub 7/

    Energy Technology Data Exchange (ETDEWEB)

    Filip' ev, V.S.; Cherner, Ya.E.; Bunina, O.A.; Seregin, V.F.

    The structure of new Ho/sub 2/Sc NbO/sub 7/ and Sm/sub 2/ScTaO/sub 7/ compounds synthesized by the three-stage roasting at 1100-1350 deg C was investigated. Powdergrams of the synthesized compounds indicated to be like the cubic structure of pyrochlore type. Periods of unit cells were determined by Bragg reflex angles. The dependence of unreliability factor on values of the position parameter of oxygen x atoms was calculated. Data were obtained that indirectly indicated a substantial disorder in the disposition of Ho and Sc atoms over A and B positions. Values of bond lengths and valence angles were presented.

  11. Surface Structure Spread Single Crystals ((SC)-C-4): Preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    de Alwis, A; Holsclaw, B; Pushkarev, V V; Reinicker, A; Lawton, T J; Blecher, M E; Sykes, E C. H.; Gellman, A J

    2013-02-01

    A set of six spherically curved Cu single crystals referred to as Surface Structure Spread Single Crystals (S{sup 4}Cs) has been prepared in such a way that their exposed surfaces collectively span all possible crystallographic surface orientations that can be cleaved from the face centered cubic Cu lattice. The method for preparing these S{sup 4}Cs and for finding the high symmetry pole point are described. Optical profilometry has been used to determine the true shapes of the S{sup 4}Cs and show that over the majority of the surface, the shape is extremely close to that of a perfect sphere. The local orientations of the surfaces lie within ±1{degree} of the orientation expected on the basis of the spherical shape; their orientation is as good as that of many commercially prepared single crystals. STM imaging has been used to characterize the atomic level structure of the Cu(111)±11{degree}-S{sup 4}C. This has shown that the average step densities and the average step orientations match those expected based on the spherical shape. In other words, although there is some distribution of step-step spacing and step orientations, there is no evidence of large scale reconstruction or faceting. The Cu S{sup 4}Cs have local structures based on the ideal termination of the face centered cubic Cu lattice in the direction of termination. The set of Cu S{sup 4}Cs will serve as the basis for high throughput investigations of structure sensitive surface chemistry on Cu.

  12. Synthesis, crystal structure and magnetic properties of new indium rhenium and scandium rhenium oxides, In 6ReO 12 and Sc 6ReO 12

    Science.gov (United States)

    Mikhailova, D.; Ehrenberg, H.; Fuess, H.

    2006-12-01

    The new complex indium rhenium and scandium rhenium oxides, In 6ReO 12 and Sc 6ReO 12, have been synthesized as single phases in sealed silica tubes and by high-pressure high-temperature syntheses, and their crystal structures have been determined by single crystal X-ray diffraction.The compounds crystallize in a rhombohedral structure related to the distorted fluorite structure like Ln 6ReO 12 for some rare earth elements, S. G.: R-3, Z=3, aH= 9.248(2) Å, cH=8.720(2) Å for Sc 6ReO 12 and aH=9.492(1) Å, cH=8.933(1) Å for In 6ReO 12. A maximum in magnetization is observed for Sc 6ReO 12 at T( Mmax)=1.89(2) K, whereas ferromagnetic ordering is found for In 6ReO 12 by a pronounced increase in the temperature dependence of magnetization at TC=7.5(5) K. The magnetic moment per rhenium ion in In 6ReO 12 and Sc 6ReO 12 is 0.84(1) and 0.65(1) μB, respectively, derived from the paramagnetic regions.

  13. Synthesis and crystallization of titanium dioxide in supercritical carbon dioxide (scCO2)

    Science.gov (United States)

    Kaleva, A.; Heinonen, S.; Nikkanen, J.-P.; Levänen, E.

    2017-02-01

    In this work, a simple and low-temperature method to synthesize titanium dioxide (TiO2) particles with supercritical carbon dioxide is presented. The particles were synthesized by measuring 5 ml of tetra-n-butyl orthotitanate precursor to the supercritical chamber. The pressure was maintained at 15.0 MPafor all experiments. Reaction temperatures used were 50 °C or 70 °C. After reaching treatment parameters 10 ml of deionized water was introduced to the chamber with a co-solvent pump. A mixer was used inside the chamber to ensure proper mixing of water and precursor. Reaction times of 10, 60 and 300 min were used. Characterization of the particle crystal phase was determined by X-ray diffraction, differential scanning calorimetry and transmission electron microscopy. The specific surface areas were measured with nitrogen adsorption tests (BET). The results showed that the particles synthesized with reaction times of 10 and 60 min contained brookite as the crystalline phase. With longer reaction time of 300 min the phase shifted to anatase. In most experiments there was also significant amount of amorphous phase present. The specific surface areas varied between 274.3–566.6 m2/g.

  14. Diode-pumped laser performance of Tm:Sc2SiO5 crystal at 1971 nm

    Science.gov (United States)

    Liu, Bin; Zheng, Li-He; Wang, Qing-Guo; Liu, Jun-Fang; Su, Liang-Bi; Tang, Hui-Li; Liu, Jie; Fan, Xiu-Wei; Wu, Feng; Luo, Ping; Zhao, Heng-Yu; Shi, Jiao-Jiao; He, Nuo-Tian; Li, Na; Li, Qiu; Guo, Chao; Xu, Xiao-Dong; Wang, Zhan-Shan; Xu, Jun

    2017-08-01

    Not Available Project supported by the Shanghai Municipal Engineering Research Center for Sapphire Crystals, China (Grant No. 14DZ2252500), the Fund of Key Laboratory of Optoelectronic Materials Chemistry and Physics, Chinese Academy of Sciences (Grant No. 2008DP17301), the Fundamental Research Funds for the Central Universities, the National Natural Science Foundation of China and the China Academy of Engineering Physics Joint Fund (Grant No. U1530152), the National Natural Science Foundation of China (Grant Nos. 61475177 and 61621001), the Shanghai Municipal Natural Science Foundation, China (Grant No. 13ZR1446100), and the MDE Key Laboratory of Advanced Micro-Structured Materials.

  15. A study of the crystal structures and the phase transitions of the ordered double perovskites Sr{sub 2}ScSbO{sub 6} and Ca{sub 2}ScSbO{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Faik, A., E-mail: afaik@cicenergigune.com [Fisika Aplikatua II Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea, P.O.Box 644, Bilbao 48080 (Spain); CICenergigune, Parque Tecnologico, Albert Einstein 48, 01510 Minano, Alava (Spain); Orobengoa, D. [Departamento de Fisica de la Materia Condensada, Universidad del Pais Vasco, E-48080 Bilbao (Spain); Iturbe-Zabalo, E.; Igartua, J.M. [Fisika Aplikatua II Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea, P.O.Box 644, Bilbao 48080 (Spain)

    2012-08-15

    The crystal structures and phase transitions of the two ordered double perovskites Sr{sub 2}ScSbO{sub 6} and Ca{sub 2}ScSbO{sub 6} were studied using conventional X-ray and neutron powder-diffraction methods. The crystal structures of both compounds have the P2{sub 1}/n space group symmetry at room temperature, resulting from Sc/Sb ordering. The evolution with temperature of the structure of the Sr containing compound shows the presence of three phase transitions with the following sequence: P2{sub 1}/n{yields}I2/m{yields}I4/m{yields}Fm3{sup Macron }m, at about 400, 560 and 650 K, respectively. The smaller size of Ca cation, with respect to that of Sr cation, leads to a large distortion of Ca{sub 2}ScSbO{sub 6} at room temperature. This fact in turn causes that the Ca containing compound shows only the first phase transition from P2{sub 1}/n to I2/m at high temperature at about 1440 K. The analysis of the phase transitions and the refinements have done using the symmetry-adapted modes and the tools of the Bilbao Crystallographic Server. - Graphical abstract: Representation of the new structure resulting from the coupling of the unidimensional GM{sup 4+} and X{sup 3+} modes with the a{sup +}b{sup -}b{sup -} tilting scheme associated to P2{sub 1}/n and the temperature evolution of the amplitudes of the GM{sup 1+}, GM{sup 3+}, GM{sup 4+} and GM{sup 5+} modes of I2/m and I4/m space groups obtained from the NPD data of Sr{sub 2}ScSbO{sub 6}. Highlights: Black-Right-Pointing-Pointer Study of two compounds of the antimony double perovskite family. Black-Right-Pointing-Pointer Determination of the structures at room temperature. Black-Right-Pointing-Pointer Determination of high-temperature phase transitions by X-ray and neutron powder diffraction. Black-Right-Pointing-Pointer Using the symmetry-adapted modes to study the phase transitions.

  16. Influence of Phase Transformations on Crystal Growth of Stoichiometric Brownmillerite Oxides: Sr2ScGaO5 and Ca2Fe2O5

    Directory of Open Access Journals (Sweden)

    Monica Ceretti

    2016-11-01

    Full Text Available High quality stoichiometric brownmillerite-type oxide single crystals have been successfully grown by the floating zone method using a mirror furnace. We report here on the growth conditions and structural characterization of two model compounds: Ca2Fe2O5 and Sr2ScGaO5. Both show oxygen deficiency with respect to the average perovskite structure, and are promising candidates for oxygen ion conductivity at moderate temperatures. While Sr2ScGaO5 single crystals were obtained in the cubic oxygen-deficient perovskite structure, Ca2Fe2O5 crystallizes in the brownmillerite framework. Having no cubic parent high temperature counterpart, Ca2Fe2O5 crystals were found to be not twinned. We report on structural characterization of the as-grown single crystals by neutron and X-ray diffraction, as well as scanning electron microscopy (SEM coupled with EDX (Energy Dispersive X-Ray Spectroscopy analysis and isotope exchange experiments.

  17. Crystal field analysis of the absorption spectra and electron phonon interaction in Ca3Sc2Ge3O12:Ni2+

    Science.gov (United States)

    Brik, M. G.

    2006-04-01

    Exchange charge model of crystal field [B.Z. Malkin, in: A.A. Kaplyanskii, B.M. Macfarlane (Eds.), Spectroscopy of Solids Containing Rare-earth Ions, North-Holland, Amsterdam, 1987, pp. 33 50.] was used to analyze the energy level schemes of Ni2+ ion at both possible positions (octahedral and tetrahedral) in Ca3Sc2Ge3O12. The crystal field parameters were calculated from the crystal structure data; the crystal field Hamiltonian was diagonalised in the complete basis consisting of 25 wave functions of all LS terms of the Ni2+ ion. Results of calculations are in a good agreement with experimental data. From the experimental spectra available in the literature, the Huang Rhys parameter S=3.5 and effective phonon energy ℏω=200cm were evaluated for the octahedral Ni2+ ion.

  18. Effect of Rare Earth Elements (Er, Ho) on Semi-Metallic Materials (ScN) in an Applied Electric Field

    Science.gov (United States)

    Kim, Hyunjung; Park, Yeonjoon; King, Glen C.; Lee, Kunik; Choi, Sang H.

    2012-01-01

    The development of materials and fabrication technology for field-controlled spectrally active optics is essential for applications such as membrane optics, filters for LIDARs, windows for sensors, telescopes, spectroscopes, cameras and flat-panel displays. The dopants of rare earth elements, in a host of optical systems, create a number of absorption and emission band structures and can easily be incorporated into many high quality crystalline and amorphous hosts. In wide band-gap semiconductors like ScN, the existing deep levels can capture or emit the mobile charges, and can be ionized with the loss or capture of the carriers which are the fundamental basis of concept for smart optic materials. The band gap shrinkage or splitting with dopants supports the possibility of this concept. In the present work, a semi-metallic material (ScN) was doped with rare earth elements (Er, Ho) and tested under an applied electric field to characterize spectral and refractive index shifts by either Stark or Zeeman Effect. These effects can be verified using the UV-Vis spectroscopy, the Hall Effect measurement and the ellipsometric spectroscopy. The optical band gaps of ScN doped with Er and doped with Ho were experimentally estimated as 2.33eV and 2.24eV ( 0.2eV) respectively. This is less than that of undoped ScN (2.5 0.2eV). The red-shifted absorption onset is a direct evidence for the decrease of band gap energy (Eg), and the broadening of valence band states is attributable to the doping cases. A decrease in refractive index with an applied field was observed as a small shift in absorption coefficient using a variable angle spectroscopic ellipsometer. In the presence of an electric field, mobile carriers are redistributed within the space charge region (SCR) to produce this electro-refractive effect. The shift in refractive index is also affected by the density and location of deep potential wells within the SCR. In addition, the microstructure change was observed by a TEM

  19. Negative thermal expansion and broad band photoluminescence in a novel material of ZrScMo2VO12

    Science.gov (United States)

    Ge, Xianghong; Mao, Yanchao; Liu, Xiansheng; Cheng, Yongguang; Yuan, Baohe; Chao, Mingju; Liang, Erjun

    2016-04-01

    In this paper, we present a novel material with the formula of ZrScMo2VO12 for the first time. It was demonstrated that this material exhibits not only excellent negative thermal expansion (NTE) property over a wide temperature range (at least from 150 to 823 K), but also very intense photoluminescence covering the entire visible region. Structure analysis shows that ZrScMo2VO12 has an orthorhombic structure with the space group Pbcn (No. 60) at room temperature. A phase transition from monoclinic to orthorhombic structure between 70 and 90 K is also revealed. The intense white light emission is tentatively attributed to the n- and p-type like co-doping effect which creates not only the donor- and acceptor-like states in the band gap, but also donor-acceptor pairs and even bound exciton complexes. The excellent NTE property integrated with the intense white-light emission implies a potential application of this material in light emitting diode and other photoelectric devices.

  20. Lanthanide-doped Na xScF 3+ x nanocrystals: Crystal structure evolution and multicolor tuning

    KAUST Repository

    Teng, Xue

    2012-05-23

    Rare-earth-based nanomaterials have recently drawn considerable attention because of their unique energy upconversion (UC) capabilities. However, studies of Sc 3+-based nanomaterials are still absent. Herein we report the synthesis and fine control of Na xScF 3+x nanocrystals by tuning of the ratio of oleic acid (OA, polar surfactant) to 1-octadecene (OD, nonpolar solvent). When the OA:OD ratio was increased from low (3:17) to high (3:7), the nanocrystals changed from pure monoclinic phase (Na 3ScF 6) to pure hexagonal phase (NaScF 4) via a transition stage at an intermediate OA:OD ratio (3:9) where a mixture of nanocrystals in monoclinic and hexagonal phases was obtained and the coexistence of the two phases inside individual nanocrystals was also observed. More significantly, because of the small radius of Sc 3+, Na xScF 3+x:Yb/Er nanocrystals show different UC emission from that of NaYF 4:Yb/Er nanocrystals, which broadens the applications of rare-earth-based nanomaterials ranging from optical communications to disease diagnosis. © 2012 American Chemical Society.

  1. High-pressure synthesis and crystal structure of the borate Sc{sub 3}B{sub 5}O{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Neumair, Stephanie C.; Huppertz, Hubert [Inst. fuer Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Univ. Innsbruck (Austria)

    2009-11-15

    The rare-earth borate Sc{sub 3}B{sub 5}O{sub 12} was synthesized under high-pressure/high-temperature conditions of 6 GPa and 1100 C in a Walker-type multianvil apparatus. The single-crystal structure determination revealed an isotypy to RE{sub 3}B{sub 5}O{sub 12} (RE = Er-Lu). Sc{sub 3}B{sub 5}O{sub 12} crystallizes in the rare space group Pmna (Z = 4) with the parameters a = 1245.4(3), b = 443.46(9), c = 1222.1 (2) pm, V = 0.675(1) nm{sup 3}, R{sub 1} = 0.0520, and wR{sub 2} = 0.0860 (all data). The structure of Sc{sub 3}B{sub 5}O{sub 12} is composed of layers of condensed BO{sub 4} tetrahedra, separated by eight-fold coordinated scandium ions. (orig.)

  2. Method of making macrocrystalline or single crystal semiconductor material

    Science.gov (United States)

    Shlichta, P. J. (Inventor); Holliday, R. J. (Inventor)

    1986-01-01

    A macrocrystalline or single crystal semiconductive material is formed from a primary substrate including a single crystal or several very large crystals of a relatively low melting material. This primary substrate is deposited on a base such as steel or ceramic, and it may be formed from such metals as zinc, cadmium, germanium, aluminum, tin, lead, copper, brass, magnesium silicide, or magnesium stannide. These materials generally have a melting point below about 1000 C and form on the base crystals the size of fingernails or greater. The primary substrate has an epitaxial relationship with a subsequently applied layer of material, and because of this epitaxial relationship, the material deposited on the primary substrate will have essentially the same crystal size as the crystals in the primary substrate. If required, successive layers are formed, each of a material which has an epitaxial relationship with the previously deposited layer, until a layer is formed which has an epitaxial relationship with the semiconductive material. This layer is referred to as the epitaxial substrate, and its crystals serve as sites for the growth of large crystals of semiconductive material. The primary substrate is passivated to remove or otherwise convert it into a stable or nonreactive state prior to deposition of the seconductive material.

  3. Automating the application of smart materials for protein crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Khurshid, Sahir; Govada, Lata [Imperial College London, London SW7 2AZ (United Kingdom); EL-Sharif, Hazim F.; Reddy, Subrayal M. [University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Chayen, Naomi E., E-mail: n.chayen@imperial.ac.uk [Imperial College London, London SW7 2AZ (United Kingdom)

    2015-03-01

    The first semi-liquid, non-protein nucleating agent for automated protein crystallization trials is described. This ‘smart material’ is demonstrated to induce crystal growth and will provide a simple, cost-effective tool for scientists in academia and industry. The fabrication and validation of the first semi-liquid nonprotein nucleating agent to be administered automatically to crystallization trials is reported. This research builds upon prior demonstration of the suitability of molecularly imprinted polymers (MIPs; known as ‘smart materials’) for inducing protein crystal growth. Modified MIPs of altered texture suitable for high-throughput trials are demonstrated to improve crystal quality and to increase the probability of success when screening for suitable crystallization conditions. The application of these materials is simple, time-efficient and will provide a potent tool for structural biologists embarking on crystallization trials.

  4. Issues in the growth of bulk crystals of infrared materials

    Science.gov (United States)

    Bachmann, K. J.; Golowsky, H.

    1987-01-01

    Attention is given to the relevant criteria governing materials choice in the growth of IR optoelectronic bulk single crystals of III-V and II-VI alloy and I-III-VI2 compound types. The most important considerations concern the control of crystal purity, microstructural perfection, stoichiometry, and uniformity during crystal growth, as well as the control of surface properties in wafer fabrication. Specific examples are given to illustrate the problems encountered and their preferred solutions.

  5. Final Technical Report for DE-SC0001878 [Theory and Simulation of Defects in Oxide Materials

    Energy Technology Data Exchange (ETDEWEB)

    Chelikowsky, James R. [University of Texas at Austin

    2014-04-14

    We explored a wide variety of oxide materials and related problems, including materials at the nanoscale and generic problems associated with oxide materials such as the development of more efficient computational tools to examine these materials. We developed and implemented methods to understand the optical and structural properties of oxides. For ground state properties, our work is predominantly based on pseudopotentials and density functional theory (DFT), including new functionals and going beyond the local density approximation (LDA): LDA+U. To study excited state properties (quasiparticle and optical excitations), we use time dependent density functional theory, the GW approach, and GW plus Bethe-Salpeter equation (GW-BSE) methods based on a many-body Green function approaches. Our work focused on the structural, electronic, optical and magnetic properties of defects (such as oxygen vacancies) in hafnium oxide, titanium oxide (both bulk and clusters) and related materials. We calculated the quasiparticle defect states and charge transition levels of oxygen vacancies in monoclinic hafnia. we presented a milestone G0W0 study of two of the crystalline phases of dye-sensitized TiO{sub 2} clusters. We employed hybrid density functional theory to examine the electronic structure of sexithiophene/ZnO interfaces. To identify the possible effect of epitaxial strain on stabilization of the ferromagnetic state of LaCoO{sub 3} (LCO), we compare the total energy of the magnetic and nonmagnetic states of the strained theoretical bulk structure.

  6. Status update of ISO TC67/SC8/WG5: Materials for arctic applications

    NARCIS (Netherlands)

    Hauge, M.; Maier, M.; Walters, C.L.; Ostby, E.; Kordonets, S.M.; Zanfir, C.; Osvoll, H.

    2015-01-01

    An ISO subcommittee was set up in 2011 to improve the existing standards and norms with respect to arctic offshore operations for the petroleum, petrochemical, and natural gas industries. Within this subcommittee, a specific working group was established to address the application of materials in th

  7. Mechanical Testing of 3D Fabric Composites and Their Matrix Material SC-15

    Science.gov (United States)

    2012-11-01

    Anthony M. Compressive Response of Z-pinned Woven Glass Fiber Textile Composite Laminates . Composites Science and Technology 2009, 69, 2331–2337...3. Huang, Hsengji; Waas,, Anthony M. Compressive Response of Z-pinned Woven Glass Fiber Textile Composite Laminates : Modeling and Computations...materials on military vehicles allows increased agility while maintaining a light- weight primary structure. Traditional laminated structures suffer from

  8. In situ synchrotron IR microspectroscopy of CO2 adsorption on single crystals of the functionalized MOF Sc2(BDC-NH2)3.

    Science.gov (United States)

    Greenaway, Alex; Gonzalez-Santiago, Berenice; Donaldson, Paul M; Frogley, Mark D; Cinque, Gianfelice; Sotelo, Jorge; Moggach, Stephen; Shiko, Elenica; Brandani, Stefano; Howe, Russell F; Wright, Paul A

    2014-12-01

    Synchrotron radiation (SR) IR microspectroscopy has enabled determination of the thermodynamics, kinetics, and molecular orientation of CO2 adsorbed in single microcrystals of a functionalized metal-organic framework (MOF) under conditions relevant to carbon capture from flue gases. Single crystals of the small-pore MOF, Sc2 (BDC-NH2 )3 , (BDC-NH2 =2-amino-1,4-benzenedicarboxylate), with well-defined crystal form have been investigated during CO2 uptake at partial pressures of 0.025-0.2 bar at 298-373 K. The enthalpy and diffusivity of adsorption determined from individual single crystals are consistent with values obtained from measurements on bulk samples. The brilliant SR IR source permits rapid collection of polarized spectra. Strong variations in absorbance of the symmetric stretch of the NH2 groups of the MOF and the asymmetric stretch of the adsorbed CO2 at different orientations of the crystals relative to the polarized IR light show that CO2 molecules align along channels in the MOF. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Crystal-Field Engineering of Solid-State Laser Materials

    Science.gov (United States)

    Henderson, Brian; Bartram, Ralph H.

    2005-08-01

    This book examines the underlying science and design of laser materials. It emphasizes the principles of crystal-field engineering and discusses the basic physical concepts that determine laser gain and nonlinear frequency conversion in optical crystals. Henderson and Bartram develop the predictive capabilities of crystal-field engineering to show how modification of the symmetry and composition of optical centers can improve laser performance. They also discuss applications of the principles of crystal-field engineering to a variety of optical crystals in relation to the performances of laser devices. This book will be of considerable interest to physical, chemical and material scientists and to engineers involved in the science and technology of solid state lasers.

  10. Design and Fabrication of Photonic Crystal Materials and Components

    DEFF Research Database (Denmark)

    Harpøth, Anders

    2005-01-01

    in the deposited silicon films and to open for a potential use with photonic crystals. In relation to photonic crystal structures, different properties have been investigated by using modelling tools such as the plane wave expansion method and the Finite-Difference Time-Domain method. Furthermore different......The work described in this thesis covers the issues of producing materials for use as base material for fabricating photonic crystals and the design, fabrication and characterization of photonic crystal components. One of the aims is to investigate the possibilities of fabricating a silicon...... is in principle rather straightforward and benefits from being much cheaper compared to acquiring commercially available SOI substrates. Different issues as deposition temperature, surface roughness, crystallization, and silicon waveguide geometries have been investigated in order to reduce the optical loss...

  11. Colloidal-crystal-assisted patterning of crystalline materials.

    Science.gov (United States)

    Li, Cheng; Qi, Limin

    2010-04-06

    Colloidal crystals have shown great potential as versatile templates for the fabrication of patterned micro- and nanostructures with complex architectures and novel properties. The patterning of functional crystalline materials in two and three dimensions is essential to the realization of their applications in many technologically important fields. This article highlights some recent progress in the fabrication of 2D and 3D patterned crystalline materials with the assistance of colloidal crystals. By combining a bioinspired synthetic strategy based on a transient amorphous phase with a colloidal-crystal templating method, unique 3D ordered macroporous (3DOM) calcite single crystals can be created. Moreover, patterned arrays of regular ZnO nanopillars with controlled size, shape, and orientation can be fabricated via a facile wet chemical approach by using masks derived from monolayer colloidal crystals (MCC).

  12. Growth and characterization of organic material 4-dimethylaminobenzaldehyde single crystal

    Science.gov (United States)

    Jebin, R. P.; Suthan, T.; Rajesh, N. P.; Vinitha, G.; Madhusoodhanan, U.

    2015-01-01

    The organic material 4-dimethylaminobenzaldehyde single crystals were grown by slow evaporation technique. The grown crystal was confirmed by the single crystal and powder X-ray diffraction analyses. The functional groups of the crystal have been identified from the Fourier Transform Infrared (FTIR) and FT-Raman studies. The optical property of the grown crystal was analyzed by UV-Vis-NIR and photoluminescence (PL) spectral measurements. The thermal behavior of the grown crystal was analyzed by thermogravimetric (TG) and differential thermal analyses (DTA). Dielectric measurements were carried out with different frequencies by using parallel plate capacitor method. The third order nonlinear optical properties of 4-dimethylaminobenzaldehyde was measured by the Z-scan technique using 532 nm diode pumped continuous wave (CW) Nd:YAG laser.

  13. Crystallization and structural approaches of rare earths aluminosilicate glasses (Ln = La, Y, Sc); Comportement a la cristallisation et approches structurales des verres aluminosilicates de terres rares (Ln = La, Y et Sc)

    Energy Technology Data Exchange (ETDEWEB)

    Sadiki, N.; Coutures, J.P. [PROMES, CNRS, Rambla de la Thermodynamique, Tecnosud, 66100 Perpignan (France); Hennet, L.; Florian, P.; Vaills, Y.; Massiot, D. [CEMHTI, CNRS, 1D av. de la Recherche Scientifique, 45071 Orleans Cedex 2 (France)

    2010-07-01

    The crystallization behaviour of aluminosilicate glasses of lanthanum, yttrium and scandium has been studied by DTA, XRD, SEM-EDX and EPMA analysis. Young modulus E and hardness H have been measured by using nano-indentation and elastic modulus C{sub 11} and C{sub 44} by Brillouin scattering. The Young modulus measured by nano-indentation agree to those determined by Brillouin scattering and those calculated using Makishima-Mackenzie and Rocherulle model's. The results of DTA analysis indicate that (a) the glass transition temperatures T{sub g} are higher for yttrium and scandium containing glasses than their lanthanum counterparts, the melting observed in the yttrium glasses and recently in the scandium glasses correspond to the ternary eutectic Ln{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-SiO{sub 2} (Ln = Y, Sc) (b) the thermal stability is strongly related to the ionic radii of the rare earth. The last results obtained on scandium containing glasses confirm this hypothesis. The XRD results show that the nature of the observed crystallized phases is consistent with the phase diagrams. We also have investigated by NMR-MAS of {sup 27}Al (high field- 17.6 T) these glasses. The results indicate that Al(V) species are correlated to the ionic radii of the rare earth. X-rays and neutron scattering experiments have been respectively performed on the high energy diffraction beam lines ID11 and ID15 at ESRF. The interatomic distances and first-shell coordination numbers were determined. The results are consistent with those performed by NMR-MAS. (authors)

  14. Holographic Polymer-Dispersed Liquid Crystals: Materials, Formation, and Applications

    Directory of Open Access Journals (Sweden)

    Y. J. Liu

    2008-01-01

    Full Text Available By combining polymer-dispersed liquid crystal (PDLC and holography, holographic PDLC (H-PDLC has emerged as a new composite material for switchable or tunable optical devices. Generally, H-PDLC structures are created in a liquid crystal cell filled with polymer-dispersed liquid crystal materials by recording the interference pattern generated by two or more coherent laser beams which is a fast and single-step fabrication. With a relatively ideal phase separation between liquid crystals and polymers, periodic refractive index profile is formed in the cell and thus light can be diffracted. Under a suitable electric field, the light diffraction behavior disappears due to the index matching between liquid crystals and polymers. H-PDLCs show a fast switching time due to the small size of the liquid crystal droplets. So far, H-PDLCs have been applied in many promising applications in photonics, such as flat panel displays, switchable gratings, switchable lasers, switchable microlenses, and switchable photonic crystals. In this paper, we review the current state-of-the-art of H-PDLCs including the materials used to date, the grating formation dynamics and simulations, the optimization of electro-optical properties, the photonic applications, and the issues existed in H-PDLCs.

  15. Energetic materials: crystallization, characterization and insensitive plastic bonded explosives

    NARCIS (Netherlands)

    Heijden, A.E.D.M. van der; Creyghton, Y.L.M.; Marino, E.; Bouma, R.H.B.; Scholtes, G.J.H.G.; Duvalois, W.; Roelands, C.P.M.

    2008-01-01

    The product quality of energetic materials is predominantly determined by the crystallization process applied to produce these materials. It has been demonstrated in the past that the higher the product quality of the solid energetic ingredients, the less sensitive a plastic bonded explosive contain

  16. Energetic materials: crystallization, characterization and insensitive plastic bonded explosives

    NARCIS (Netherlands)

    Heijden, A.E.D.M. van der; Creyghton, Y.L.M.; Marino, E.; Bouma, R.H.B.; Scholtes, G.J.H.G.; Duvalois, W.; Roelands, C.P.M.

    2008-01-01

    The product quality of energetic materials is predominantly determined by the crystallization process applied to produce these materials. It has been demonstrated in the past that the higher the product quality of the solid energetic ingredients, the less sensitive a plastic bonded explosive

  17. Study of the Mn-Mn exchange interactions in single crystals of RMn{sub 6}Sn{sub 6} compounds with R = Sc, Y and Lu

    Energy Technology Data Exchange (ETDEWEB)

    Matsuo, A. [KYOKUGEN, Osaka University, Toyonaka, Osaka 560-8531 (Japan)]. E-mail: a-matsuo@issp.u-tokyo.ac.jp; Suga, K. [KYOKUGEN, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Kindo, K. [KYOKUGEN, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Zhang, L. [Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, 1018 XE Amsterdam (Netherlands); Brueck, E. [Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, 1018 XE Amsterdam (Netherlands); Buschow, K.H.J. [Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, 1018 XE Amsterdam (Netherlands); Boer, F.R. de [KYOKUGEN, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, 1018 XE Amsterdam (Netherlands); Lefevre, C. [Lab. Chim. Sol. Mineral, Universite Henri Poincare-Nancy 1, 54506 Vandoeuvre les Nancy Cedex (France); Venturini, G. [Lab. Chim. Sol. Mineral, Universite Henri Poincare-Nancy 1, 54506 Vandoeuvre les Nancy Cedex (France)

    2006-02-09

    In order to investigate the behaviour of the magnetic anisotropy and the Mn-Mn exchange interaction in RMn{sub 6}Sn{sub 6} (R = rare earth) compounds, magnetic studies have been carried out on single crystals of RMn{sub 6}Sn{sub 6} compounds in which R is one of the non-magnetic elements Sc, Y and Lu. The temperature dependence of the magnetization of these compounds has been measured with the field applied parallel and perpendicular to the crystallographic c-direction. Magnetic isotherms of the three compounds were measured at 4.2 K in magnetic fields up to 50 T, applied parallel and perpendicular to the c-direction, sufficiently high to reach the forced ferromagnetic state and to detect multiple field-induced transitions. For LuMn{sub 6}Sn{sub 6}, magnetic isotherms were measured also at a higher temperature of 150 K. From our results we may conclude that the magnetic anisotropy as well as the antiferromagnetic coupling strength increases in the sequence of ScMn{sub 6}Sn{sub 6}, YMn{sub 6}Sn{sub 6} and LuMn{sub 6}Sn{sub 6}.

  18. AUTOMATED DETERMINATION OF THE CRYSTALS SIZE IN ELECTRODEPOSITED METAL MATERIALS

    Directory of Open Access Journals (Sweden)

    E. V. Kolesnik

    2014-01-01

    Full Text Available Methods of automated determination of the crystals size in the electrodeposited metal materials including digital processing of the electronicand microscopic image of the structure with sequential use of the low-and-high-leaky filter based on fast transformation of Fourier, Watershed-algorithm and decomposing of Voronoj with further measurement of thr crystal size with one of the traditional methods is offered.

  19. Locating Gases in Porous Materials: Cryogenic Loading of Fuel-Related Gases Into a Sc-based Metal-Organic Framework under Extreme Pressures.

    Science.gov (United States)

    Sotelo, Jorge; Woodall, Christopher H; Allan, Dave R; Gregoryanz, Eugene; Howie, Ross T; Kamenev, Konstantin V; Probert, Michael R; Wright, Paul A; Moggach, Stephen A

    2015-11-02

    An alternative approach to loading metal organic frameworks with gas molecules at high (kbar) pressures is reported. The technique, which uses liquefied gases as pressure transmitting media within a diamond anvil cell along with a single-crystal of a porous metal-organic framework, is demonstrated to have considerable advantages over other gas-loading methods when investigating host-guest interactions. Specifically, loading the metal-organic framework Sc2BDC3 with liquefied CO2 at 2 kbar reveals the presence of three adsorption sites, one previously unreported, and resolves previous inconsistencies between structural data and adsorption isotherms. A further study with supercritical CH4 at 3-25 kbar demonstrates hyperfilling of the Sc2 BDC3 and two high-pressure displacive and reversible phase transitions are induced as the filled MOF adapts to reduce the volume of the system. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Heterogeneous Monolithic Integration of Single-Crystal Organic Materials.

    Science.gov (United States)

    Park, Kyung Sun; Baek, Jangmi; Park, Yoonkyung; Lee, Lynn; Hyon, Jinho; Koo Lee, Yong-Eun; Shrestha, Nabeen K; Kang, Youngjong; Sung, Myung Mo

    2017-02-01

    Manufacturing high-performance organic electronic circuits requires the effective heterogeneous integration of different nanoscale organic materials with uniform morphology and high crystallinity in a desired arrangement. In particular, the development of high-performance organic electronic and optoelectronic devices relies on high-quality single crystals that show optimal intrinsic charge-transport properties and electrical performance. Moreover, the heterogeneous integration of organic materials on a single substrate in a monolithic way is highly demanded for the production of fundamental organic electronic components as well as complex integrated circuits. Many of the various methods that have been designed to pattern multiple heterogeneous organic materials on a substrate and the heterogeneous integration of organic single crystals with their crystal growth are described here. Critical issues that have been encountered in the development of high-performance organic integrated electronics are also addressed.

  1. Influence of Sc3+ doping in B-site on electrochemical performance of Li4Ti5O12 anode materials for lithium-ion battery

    Science.gov (United States)

    Zhang, Yaoyao; Zhang, Chunming; Lin, Ye; Xiong, Ding-Bang; Wang, Dan; Wu, Xiaoyan; He, Dannong

    2014-03-01

    Anode materials Li4Ti5O12 (LTO) and Sc-doped Li4Ti4.95Sc0.05O12-δ (LTSO) for lithium-ion batteries are both successfully synthesized by the modified sol-gel method with ethylene diamine tetraacetic acid (EDTA) and citric acid (CA) as a bi-components chelating agent. The samples are characterized by XRD, BET, XPS, EDX and SEM. The dopant Sc totally enters into the 16d sites of the spinel structure of LTO, and then further affects its morphology and property. The LTSO powder exhibits a 3D network morphology and its grain size is about 200 nm. The LTSO electrode material exhibits an excellent initial discharge capacities of 174 and 94 mAh g-1 at 1 C and 40 C, respectively. The reversible capacities of LTSO at different current rates remain nearly 100% after 50 cycles, which are compared with the capacities of the second cycles. Sc3+ doping can greatly improve the electronic conductivity of LTO which is demonstrated by electrochemical impedance spectroscopy. Cyclic voltammetry measurements also reveal that LTSO has small polarization resistance due to the high electrical conductivity and Li-ion apparent diffusion rate.

  2. Phase composition, structure and properties of (ZrO2)1-x-y(Sc2O3)x(Y2O3)y solid solution crystals (x=0.08-0.11; y=0.01-0.02) grown by directional crystallization of the melt

    Science.gov (United States)

    Borik, M. A.; Bredikhin, S. I.; Bublik, V. T.; Kulebyakin, A. V.; Kuritsyna, I. E.; Lomonova, E. E.; Milovich, F. O.; Myzina, V. A.; Osiko, V. V.; Ryabochkina, P. A.; Seryakov, S. V.; Tabachkova, N. Yu.

    2017-01-01

    For the first time crystals of the (ZrO2)1-x-y(Sc2O3)x(Y2O3)y solid solutions (x=0.08-0.11; y=0.01-0.02) have been grown by directional melt crystallization. We have determined the range of melt compositions for which growth from the melt produces of the (ZrO2)1-x-y(Sc2O3)x(Y2O3)y solid solution single crystals. The single-phase optically transparent single crystals following composition were grown: (ZrO2)0.9(Sc2O3)0.08(Y2O3)0.02; (ZrO2)0.89(Sc2O3)0.09(Y2O3)0.02; (ZrO2)0.89(Sc2O3)0.10(Y2O3)0.01; (ZrO2)0.88(Sc2O3)0.10(Y2O3)0.02. Comprehensive study of the crystal structure by using XRD, transmission electron microscopy, and Raman spectroscopy revealed that the all single crystals, which is identified by XRD data as cubic one, in fact have t″ tetragonal structure, which forms by small displacement of oxygen ions along the c-axis. Data on the phase stability of the crystals during mechanical crushing were obtained. The electrical conductivity was measured as a function of temperature by electrochemical impedance spectroscopy. It is established that (ZrO2)0.89(Sc2O3)0.10(Y2O3)0.01 crystals have the highest conductivity (0.168 S/cm at 1173 K).

  3. Molecular and crystal design of nonlinear optical organic materials

    Energy Technology Data Exchange (ETDEWEB)

    Suponitsky, Kirill Yu; Antipin, Mikhail Yu [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow (Russian Federation); Timofeeva, Tatiana V [Department of Chemistry, New Mexico Highlands University (United States)

    2006-06-30

    The results of theoretical and experimental studies on the second-order molecular and crystal nonlinear optical susceptibilities of organic and several classes of organoelement compounds are summarised. Modern methods used in these studies are briefly characterised, their advantages and drawbacks are outlined as regards their application to the systematic search for efficient nonlinear optical materials. Recent achievements and the main challenges in the field are thoroughly discussed and an optimum algorithm of the design of such materials is proposed.

  4. Encapsulation of energetic materials by cooling and electrospray crystallization

    NARCIS (Netherlands)

    Reus, M.A.; Horst, J.H. ter; Stankiewicz, A.I.; Heijden, A.E.D.M. van der

    2012-01-01

    In this work cooling and electrospray crystallization have been used to create encapsulated (sub-)micron sized particles of different crystalline materials. Encapsulation experiments have been conducted, creating the core particle in situ from solution, with the model systems isonicotinamide (INA) –

  5. Encapsulation of energetic materials by cooling and electrospray crystallization

    NARCIS (Netherlands)

    Reus, M.A.; Horst, J.H. ter; Stankiewicz, A.I.; Heijden, A.E.D.M. van der

    2012-01-01

    In this work cooling and electrospray crystallization have been used to create encapsulated (sub-)micron sized particles of different crystalline materials. Encapsulation experiments have been conducted, creating the core particle in situ from solution, with the model systems isonicotinamide (INA) –

  6. Constitutive Model for an FCC Single-Crystal Material

    Institute of Scientific and Technical Information of China (English)

    DING Zhi-ping; LIU Yi-lun; YIN Ze-yong; YANG Zhi-guo; CHENG Xiao-ming

    2006-01-01

    Talking into account the effects that the components of tension stresses couple with components of torsion stresses when off-axis loads are applied to orthotropic materials.Hill's yield criterion for plastically orthotropic solids is modified by adding an invariant that is composed of the product item of quadratic components of the deviatoric siress tensor,and a new yield criteflon is put forward in terms of the characteristics of the face-centered cubic(FCC) single-crystal material.The correlation of prediction and experiments is very good.and the new criterion is used to predict the yield stresses of an intemal single-crystal,Nickel-based superalloy,DD3,which is more accurate than that Of Hill's at 760°C.Equivalent stress and strain that adapt to the new criterion are defined.Thinking of the yield function as a plastic potential function from the associated flow rule.the elastic-plastic constitutive model for the FCC single-crystal material is constructed,and the corresponding elastic-plastic matrix iseduced.The new yield criterion and its equivalent stress and strain will be reduced to Von Mises' yield criterion and corresponding equivalent stress and strain for isotropic materials.

  7. Phononic crystals with one-dimensional defect as sensor materials

    Science.gov (United States)

    Aly, Arafa H.; Mehaney, Ahmed

    2017-09-01

    Recently, sensor technology has attracted great attention in many fields due to its importance in many engineering applications. In the present work, we introduce a study using the innovative properties of phononic crystals in enhancing a new type of sensors based on the intensity of transmitted frequencies inside the phononic band gaps. Based on the transfer matrix method and Bloch theory, the expressions of the reflection coefficient and dispersion relation are presented. Firstly, the influences of filling fraction ratio and the angle of incidence on the band gap width are discussed. Secondly, the localization of waves inside band gaps is discussed by enhancing the properties of the defected phononic crystal. Compared to the periodic structure, localization modes involved within the band structure of phononic crystals with one and two defect layers are presented and compared. Trapped localized modes can be detected easily and provide more information about defected structures. Such method could increase the knowledge of manufacturing defects by measuring the intensity of propagated waves in the resonant cavities and waveguides. Moreover, several factors enhance the role of the defect layer on the transmission properties of defected phononic crystals are presented. The acoustic band gap can be used to detect or sense the type of liquids filling the defect layer. The liquids make specific resonant modes through the phononic band gaps that related to the properties of each liquid. The frequency where the maximum resonant modes occur is correlated to material properties and allows to determine several parameters such as the type of an unknown material.

  8. Phononic crystals with one-dimensional defect as sensor materials

    Science.gov (United States)

    Aly, Arafa H.; Mehaney, Ahmed

    2017-04-01

    Recently, sensor technology has attracted great attention in many fields due to its importance in many engineering applications. In the present work, we introduce a study using the innovative properties of phononic crystals in enhancing a new type of sensors based on the intensity of transmitted frequencies inside the phononic band gaps. Based on the transfer matrix method and Bloch theory, the expressions of the reflection coefficient and dispersion relation are presented. Firstly, the influences of filling fraction ratio and the angle of incidence on the band gap width are discussed. Secondly, the localization of waves inside band gaps is discussed by enhancing the properties of the defected phononic crystal. Compared to the periodic structure, localization modes involved within the band structure of phononic crystals with one and two defect layers are presented and compared. Trapped localized modes can be detected easily and provide more information about defected structures. Such method could increase the knowledge of manufacturing defects by measuring the intensity of propagated waves in the resonant cavities and waveguides. Moreover, several factors enhance the role of the defect layer on the transmission properties of defected phononic crystals are presented. The acoustic band gap can be used to detect or sense the type of liquids filling the defect layer. The liquids make specific resonant modes through the phononic band gaps that related to the properties of each liquid. The frequency where the maximum resonant modes occur is correlated to material properties and allows to determine several parameters such as the type of an unknown material.

  9. Accumulated distribution of material gain at dislocation crystal growth

    Science.gov (United States)

    Rakin, V. I.

    2016-05-01

    A model for slowing down the tangential growth rate of an elementary step at dislocation crystal growth is proposed based on the exponential law of impurity particle distribution over adsorption energy. It is established that the statistical distribution of material gain on structurally equivalent faces obeys the Erlang law. The Erlang distribution is proposed to be used to calculate the occurrence rates of morphological combinatorial types of polyhedra, presenting real simple crystallographic forms.

  10. Modification of Absorption of a Bulk Material by Photonic Crystals

    Institute of Scientific and Technical Information of China (English)

    席永刚; 王昕; 胡新华; 刘晓晗; 资剑

    2002-01-01

    We show theoretically that it is possible to modify absorption of a bulk absorbing material by inserting another non-absorbing dielectric slab periodically to form one-dimensional photonic crystals. It is found that, for fre- quencies within photonic bandgaps, absorption is always suppressed. For frequencies located at photonic bands, absorption can be suppressed or enhanced, which depends on the relative values of the real refractive index of the absorbing and non-absorbing dielectric layers.

  11. Kinetic Processes Crystal Growth, Diffusion, and Phase Transformations in Materials

    CERN Document Server

    Jackson, Kenneth A

    2004-01-01

    The formation of solids is governed by kinetic processes, which are closely related to the macroscopic behaviour of the resulting materials. With the main focus on ease of understanding, the author begins with the basic processes at the atomic level to illustrate their connections to material properties. Diffusion processes during crystal growth and phase transformations are examined in detail. Since the underlying mathematics are very complex, approximation methods typically used in practice are the prime choice of approach. Apart from metals and alloys, the book places special emphasis on th

  12. Methods for the additive manufacturing of semiconductor and crystal materials

    Science.gov (United States)

    Stowe, Ashley C.; Speight, Douglas

    2016-11-22

    A method for the additive manufacturing of inorganic crystalline materials, including: physically combining a plurality of starting materials that are used to form an inorganic crystalline compound to be used as one or more of a semiconductor, scintillator, laser crystal, and optical filter; heating or melting successive regions of the combined starting materials using a directed heat source having a predetermined energy characteristic, thereby facilitating the reaction of the combined starting materials; and allowing each region of the combined starting materials to cool in a controlled manner, such that the desired inorganic crystalline compound results. The method also includes, prior to heating or melting the successive regions of the combined starting materials using the directed heat source, heating the combined starting materials to facilitate initial reaction of the combined starting materials. The method further includes translating the combined starting materials and/or the directed heat source between successive locations. The method still further includes controlling the mechanical, electrical, photonic, and/or optical properties of the inorganic crystalline compound.

  13. Methods for the additive manufacturing of semiconductor and crystal materials

    Energy Technology Data Exchange (ETDEWEB)

    Stowe, Ashley C.; Speight, Douglas

    2016-11-22

    A method for the additive manufacturing of inorganic crystalline materials, including: physically combining a plurality of starting materials that are used to form an inorganic crystalline compound to be used as one or more of a semiconductor, scintillator, laser crystal, and optical filter; heating or melting successive regions of the combined starting materials using a directed heat source having a predetermined energy characteristic, thereby facilitating the reaction of the combined starting materials; and allowing each region of the combined starting materials to cool in a controlled manner, such that the desired inorganic crystalline compound results. The method also includes, prior to heating or melting the successive regions of the combined starting materials using the directed heat source, heating the combined starting materials to facilitate initial reaction of the combined starting materials. The method further includes translating the combined starting materials and/or the directed heat source between successive locations. The method still further includes controlling the mechanical, electrical, photonic, and/or optical properties of the inorganic crystalline compound.

  14. A new material for single crystal modulators: BBO

    Science.gov (United States)

    Bammer, F.; Schumi, T.; Petkovsek, R.

    2011-06-01

    Single crystal photo-elastic modulators (SCPEM) are based on a single piezo-electric crystal which is electrically excited on a resonance frequency such that the resulting resonant oscillation causes a modulated artificial birefringence due to the photo-elastic effect. Polarized light experience in such a crystal a strong modulation of polarization, which, in connection with a polarizer, can be used for Q-switching of lasers with pulse repetition frequencies in the range of 100- 1000 kHz. A particularly advantageous configuration is possible with crystals from the symmetry class 3m. Besides LiTaO3 and LiNbO3, both already well explored as SCPEM-materials, we introduce now BBO, which offers a very low absorption in the near infrared region and is therefore particularly suited for Q-switching of solid state lasers. We demonstrate first results of such a BBO-modulator with the dimensions 8.6 x 4.05 x 4.5mm in x-, y-, z- direction, which offers a useful resonance and polarization modulation at 131.9 kHz. Since the piezo-electric effect is small, the voltage amplitude for achieving Q-switching for an Nd:YAG-laser is expected to be in the range of 100V. Nevertheless it is a simple and robust device to achieve Q-switching with a high fixed repetition rate for high power solid state lasers.

  15. 高浓度Er3+掺杂Y3Sc2Ga3O12晶体的吸收光谱与晶体场模型研究%Absorption sp ectra and crystal-field mo deling of Er3+doped in Y3Sc2Ga3O12 crystal

    Institute of Scientific and Technical Information of China (English)

    高进云; 孙敦陆; 罗建乔; 李秀丽; 刘文鹏; 张庆礼; 殷绍唐

    2014-01-01

    Er3+-doped Y3Sc2Ga3O12 (Er:YSGG) single crystal is grown by Czochralski method successfully, and the absorp-tion spectra are measured in a wider spectral wavelength range (340-1700 nm). The experimental energy levels are analyzed and identified. The free-ion and crystal-field parameters are fitted by the experimental energy levels with a root mean square deviation of 10.34 cm-1, and 102 Stark energy levels of Er3+ in YSGG host crystals are assigned. It indicates that the fitting results of Stark energy levels are more satisfactory with the experimental spectra. Finally, the fitting results of free-ion and crystal-field parameters are compared with those already reported of Er:YAG crystal. A conclusion is drawn that the Er:YSGG has higher laser efficiency than Er:YAG, which may result from Er:YSGG that has a strong crystal field interaction.%采用提拉法生长出了高浓度掺铒(35 at%)钇钪镓石榴石(Er:YSGG)激光晶体.测试了该晶体在340-1700 nm波段内的吸收光谱,对其中Er3+的实验能级进行了分析指认.用Er:YSGG的102个实验Stark能级,拟合了它的自由离子参数和晶体场参数,均方根误差(拟合精度)σ为10.34 cm-1.结果表明,参数化Stark 能级的拟合结果与实验光谱符合得较好.将拟合得到的Er:YSGG实验结果与文献中已报道Er:YAG的自由离子参数和晶体场参数进行了比较.指出Er:YSGG具有较强的晶体场相互作用或许是其激光效率较高的主要原因之一.

  16. Materials processing threshold report. 1: Semiconductor crystals for infrared detectors

    Science.gov (United States)

    Sager, E. V.; Thompson, T. R.; Nagler, R. G.

    1980-01-01

    An extensive search was performed of the open literature pertaining to infrared detectors to determine what constitutes a good detector and in what way performance is limited by specific material properties. Interviews were conducted with a number of experts in the field to assess their perceptions of the state of the art and of the utility of zero-gravity processing. Based on this information base and on a review of NASA programs in crystal growth and infrared sensors, NASA program goals were reassessed and suggestions are presented as to possible joint and divergent efforts between NASA and DOD.

  17. Cholesteric liquid crystals as multi-purpose sensor materials

    Energy Technology Data Exchange (ETDEWEB)

    Lisetski, L. N. [National Academy of Sciences of Ukraine, Kharkov (Ukraine)

    2005-03-15

    New possibilities are discussed for Cholesteric Liquid Crystals (CLC) as sensor materials for detection of ionizing radiation, biologically active UV radiation, and the presence of hazardous vapors in atmosphere. A distinguishing property of CLC-based detectors is their 'bioequivalence', i.e., mechanisms of their response to external factors essentially imitate the corresponding mechanisms of biological tissues. Such detectors can ensure sufficiently high sensitivity to make feasible their use as alarm indicators or in biophysical studies. Specific examples are given of sensor compositions and their response characteristics.

  18. Growth of crystalline semiconductor materials on crystal surfaces

    CERN Document Server

    Aleksandrov, L

    2013-01-01

    Written for physicists, chemists, and engineers specialising in crystal and film growth, semiconductor electronics, and various applications of thin films, this book reviews promising scientific and engineering trends in thin films and thin-films materials science. The first part discusses the physical characteristics of the processes occurring during the deposition and growth of films, the principal methods of obtaining semiconductor films and of reparing substrate surfaces on which crystalline films are grown, and the main applications of films. The second part contains data on epitaxial i

  19. Tb-Dy-Fe Single Crystal and Magnetostrictive Actuator Using These Materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Magnetostrictive actuators normally use twin-crystal magnetostrictive materials as driving unit. Because the crystal and twin-crystal plane hinder the movement of the domain wall, its displacement output of low magnetic strength is rather small. Using Tb-Dy-Fe single crystal technique can effectively solve the problems brought by pollution and twin crystals, and produce high-quality Tb-Dy-Fe single crystal materials. The paper will introduce the technique of using these materials to produce magnetostrictive actuators that possess high sensitivity and resolution and use pulse feeding.

  20. Materials for Alternative Energies: Computational Materials Discovery and Crystal Structure Prediction

    Science.gov (United States)

    Wolverton, Chris

    2013-03-01

    Many of the key technological problems associated with alternative energies may be traced back to the lack of suitable materials. The materials discovery process may be greatly aided by the use of computational methods, particular those atomistic methods based on density functional theory. In this talk, we present an overview of recent work on energy-related materials from density-functional based approaches. We have developed novel computational tools which enable accurate prediction of crystal structures for new materials (using both Monte Carlo and Genetic Algorithm based approaches), materials discovery via high-throughput, data mining techniques, and automated phase diagram calculations. We highlight applications in the area of Li battery materials and hydrogen storage materials.

  1. Hierarchical structuring of liquid crystal polymer-Laponite hybrid materials.

    Science.gov (United States)

    Tritschler, Ulrich; Zlotnikov, Igor; Zaslansky, Paul; Aichmayer, Barbara; Fratzl, Peter; Schlaad, Helmut; Cölfen, Helmut

    2013-09-03

    Biomimetic organic-inorganic composite materials were fabricated via one-step self-organization on three hierarchical levels. The organic component was a polyoxazoline with pendent cholesteryl and carboxyl (N-Boc-protected amino acid) side chains that was able to form a chiral nematic lyotropic phase and bind to positively charged inorganic faces of Laponite. The Laponite particles formed a mesocrystalline arrangement within the liquid-crystal (LC) polymer phase upon shearing a viscous dispersion of Laponite nanoparticles and LC polymer in DMF. Complementary analytical and mechanical characterization techniques (AUC, POM, TEM, SEM, SAXS, μCT, and nanoindentation) covering the millimeter, micrometer, and nanometer length scales reveal the hierarchical structures and properties of the composite materials consisting of different ratios of Laponite nanoparticles and liquid-crystalline polymer.

  2. Recovery of valuable materials from waste liquid crystal display panel.

    Science.gov (United States)

    Li, Jinhui; Gao, Song; Duan, Huabo; Liu, Lili

    2009-07-01

    Associated with the rapid development of the information and electronic industry, liquid crystal displays (LCDs) have been increasingly sold as displays. However, during the discarding at their end-of-life stage, significant environmental hazards, impacts on health and a loss of resources may occur, if the scraps are not managed in an appropriate way. In order to improve the efficiency of the recovery of valuable materials from waste LCDs panel in an environmentally sound manner, this study presents a combined recycling technology process on the basis of manual dismantling and chemical treatment of LCDs. Three key processes of this technology have been studied, including the separation of LCD polarizing film by thermal shock method the removal of liquid crystals between the glass substrates by the ultrasonic cleaning, and the recovery of indium metal from glass by dissolution. The results show that valuable materials (e.g. indium) and harmful substances (e.g. liquid crystals) could be efficiently recovered or separated through above-mentioned combined technology. The optimal conditions are: (1) the peak temperature of thermal shock to separate polarizing film, ranges from 230 to 240 degrees C, where pyrolysis could be avoided; (2) the ultrasonic-assisted cleaning was most efficient at a frequency of 40 KHz (P = 40 W) and the exposure of the substrate to industrial detergents for 10 min; and (3) indium separation from glass in a mix of concentrated hydrochloric acid at 38% and nitric acid at 69% (HCl:HNO(3):H(2)O = 45:5:50, volume ratio). The indium separation process was conducted with an exposure time of 30 min at a constant temperature of 60 degrees C.

  3. Confined crystals of the smallest phase-change material.

    Science.gov (United States)

    Giusca, Cristina E; Stolojan, Vlad; Sloan, Jeremy; Börrnert, Felix; Shiozawa, Hidetsugu; Sader, Kasim; Rümmeli, Mark H; Büchner, Bernd; Silva, S Ravi P

    2013-09-11

    The demand for high-density memory in tandem with limitations imposed by the minimum feature size of current storage devices has created a need for new materials that can store information in smaller volumes than currently possible. Successfully employed in commercial optical data storage products, phase-change materials, that can reversibly and rapidly change from an amorphous phase to a crystalline phase when subject to heating or cooling have been identified for the development of the next generation electronic memories. There are limitations to the miniaturization of these devices due to current synthesis and theoretical considerations that place a lower limit of 2 nm on the minimum bit size, below which the material does not transform in the structural phase. We show here that by using carbon nanotubes of less than 2 nm diameter as templates phase-change nanowires confined to their smallest conceivable scale are obtained. Contrary to previous experimental evidence and theoretical expectations, the nanowires are found to crystallize at this scale and display amorphous-to-crystalline phase changes, fulfilling an important prerequisite of a memory element. We show evidence for the smallest phase-change material, extending thus the size limit to explore phase-change memory devices at extreme scales.

  4. Morphological control and polarization switching in polymer dispersed liquid crystal materials and devices

    Indian Academy of Sciences (India)

    K K Raina; Pankaj Kumar; Praveen Malik

    2006-11-01

    Liquid crystals dispersed in polymer systems constitute novel class of optical materials. The precise control of the liquid crystal droplet morphology in the polymer matrix is essentially required to meet the prerequisites of display device. Experiments have been carried out to investigate and identify the material properties and processing conditions required for the precise control of the droplet morphology of the dispersed liquid crystal systems. Polarization switching has been studied. Aligned liquid crystal dispersed systems showed higher polarization over unaligned ones.

  5. Crystal engineering of energetic materials: co-crystals of Ethylenedinitramine (EDNA) with modified performance and improved chemical stability.

    Science.gov (United States)

    Aakeröy, Christer B; Wijethunga, Tharanga K; Desper, John

    2015-07-27

    In the area of energetic materials, co-crystallization is emerging as a new technology for modifying or enhancing the properties of existing energetic substances. Ethylenedinitramine (EDNA) is a known energetic material which requires attention partly due to its chemical instability originating with its two highly acidic protons. In order to stabilize EDNA, a co-crystallization approach targeting the acidic protons using a series of co-crystallizing agents with suitable hydrogen-bond acceptors was employed. Fifteen attempted co-crystallizations resulted in eight successful outcomes and six of these were crystallographically characterized and all showed evidence of hydrogen bonds to the intended protons. Calculated detonation properties and experimental thermal and impact data for the co-crystals were obtained and compared with those of pure EDNA. The co-crystal of EDNA and 1,2-bis(4-pyridyl)ethylene was recognized as a more thermally stable alternative to EDNA while the co-crystal of EDNA and pyrazine N,N'-dioxide showed comparable detonation strengths (and much improved chemical stability) compared with that of EDNA. The co-crystals EDNA:4,4'-bipyridine and EDNA:pyrazine N,N'-dioxide were found to be about 50 % less impact sensitive than EDNA, all of which illustrate how co-crystallizations can be utilized for successfully modifying specific aspects of energetic materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Cs3ScCl6

    Directory of Open Access Journals (Sweden)

    Matthew D. Ward

    2014-06-01

    Full Text Available Crystals of tricaesium scandium(III hexachloride were obtained as a side product from the reaction of U, SnCl2, Sc, and S in a CsCl flux at 1073 K. Cs3ScCl6 crystallizes in the Rb3YCl6 structure type. The asymmetric unit comprises three Cs sites, two Sc sites, and six Cl sites, all of which have site symmetry 1, except for the two Sc sites that have site symmetries of 2 and -1, respectively. The structure is composed of isolated [ScCl6]3− octahedra that are surrounded by Cs+ cations. Two Cs+ cations have interactions with eight Cl− anions, while the third has interactions with ten Cl− anions.

  7. Sapphire: Relation between luminescence of starting materials and luminescence of single crystals

    Science.gov (United States)

    Mogilevsky, R.; Nedilko, S.; Sharafutdinova, L.; Burlay, S.; Sherbatskii, V.; Boyko, V.; Mittl, S.

    2009-10-01

    A relation between photoluminescence (PL) characteristics of different starting materials used for crystal growth and un-doped sapphire single crystals manufactured using various methods of crystal growth (Kyropolus, HEM, Czochralski, and EFG) was found. The crystals grown using the Verneuil starting material exhibited significant PL when any method of crystal growth was used. On the contrary, sapphire samples grown by the same technologies wherein the starting material was EMT HPDA R revealed very low PL. (HPDA R is produced by EMT, Inc., with proprietary and patented technology.)

  8. Photonic crystals to enhance light extraction from 2D materials

    CERN Document Server

    Noori, Yasir J; Roberts, Jonathan; Woodhead, Christopher; Bernardo-Gavito, Ramon; Tovee, Peter; Young, Robert J

    2016-01-01

    We propose a scheme for coupling 2D materials to an engineered cavity based on a defective rod type photonic crystal lattice. We show results from numerical modelling of the suggested cavity design, and propose using the height profile of a 2D material transferred on top of the cavity to maximise coupling between exciton recombination and the cavity mode. The photonic structure plays a key role in enhancing the launch efficiency, by improving the directionality of the emitted light to better couple it into an external optical system. When using the photonic structure, we measured an increase in the extraction ratio by a factor of 3.4. We investigated the variations in the flux spectrum when the radius of the rods is modified, and when the 2D material droops to a range of different heights within the cavity. We found an optimum enhancement when the rods have a radius equal to 0.165 times the lattice constant, this enhancement reduces when the radius is reduced or increased. Finally, we discuss the possible use...

  9. Superconductivity in Italian Secondary Schools: the experimentation carried out by Udine University with Supercomet2 (SC2) materials

    Science.gov (United States)

    Michelini, Marisa; Santi, Lorenzo; Viola, Rossana; Corni, Federico

    2008-05-01

    Through a highly interactive tools on CD, which comprises animation and films of demonstrative experiments, and uses modern pedagogical methods, such as collaborative learning and problem solving, the Supercomet 2 Project (SUPERCOnductivity Multimedia Educational Tool phase 2 of the European Union) aims to introduce superconductivity to European high school curriculums. During the first year of the project the following were produced: a CD-ROM with didactic material, a teacher's guide to clarify characteristics and roles of support material (texts, worksheets and computer presentations) and preview didactic courses. During the second year of the project It was: translated the material into the languages of countries participating in the project, experimented the application in high school classes in various parts of Europe, tested the updating course and the teacher's guide with a group of reference teachers. At the end of the first period of experimentation and dissemination were revised and new material was integrated in order to produce a final version at the end of the project. Further integrated proposals have been included with the revised material. In this paper the main characteristics realized during the project will be described.

  10. The Durability of Various Crucible Materials for Aluminum Nitride Crystal growth by Sublimation

    Energy Technology Data Exchange (ETDEWEB)

    Liu,B.; Edgar, J.; Gu, Z.; Zhuang, D.; Raghothamachar, B.; Dudley, M.; Sarua, A.; Kuball, M.; Meyer, H.

    2004-01-01

    Producing high purity aluminum nitride crystals by the sublimation-recondensation technique is difficult due to the inherently reactive crystal growth environment, normally at temperature in excess of 2100 C. The durability of the furnace fixture materials (crucibles, retorts, etc.) at such a high temperature remains a critical problem. In the present study, the suitability of several refractory materials for AlN crystal growth is investigated, including tantalum carbide, niobium carbide, tungsten, graphite, and hot-pressed boron nitride. The thermal and chemical properties and performance of these materials in inert gas, as well as under AlN crystal growth conditions are discussed. TaC and NbC are the most stable crucible materials with very low elemental vapor pressures in the crystal growth system. Compared with refractory material coated graphite crucibles, HPBN crucible is better for AlN self-seeded growth, as crystals tend to nucleate in thin colorless platelets with low dislocation density.

  11. Rhombohedral cubic semiconductor materials on trigonal substrate with single crystal properties and devices based on such materials

    Science.gov (United States)

    Park, Yeonjoon (Inventor); Choi, Sang Hyouk (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

    2012-01-01

    Growth conditions are developed, based on a temperature-dependent alignment model, to enable formation of cubic group IV, group II-V and group II-VI crystals in the [111] orientation on the basal (0001) plane of trigonal crystal substrates, controlled such that the volume percentage of primary twin crystal is reduced from about 40% to about 0.3%, compared to the majority single crystal. The control of stacking faults in this and other embodiments can yield single crystalline semiconductors based on these materials that are substantially without defects, or improved thermoelectric materials with twinned crystals for phonon scattering while maintaining electrical integrity. These methods can selectively yield a cubic-on-trigonal epitaxial semiconductor material in which the cubic layer is substantially either directly aligned, or 60 degrees-rotated from, the underlying trigonal material.

  12. Research progress on ultra-precision machining technologies for soft-brittle crystal materials

    Science.gov (United States)

    Gao, Hang; Wang, Xu; Guo, Dongming; Chen, Yuchuan

    2016-12-01

    Soft-brittle crystal materials are widely used in many fields, especially optics and microelectronics. However, these materials are difficult to machine through traditional machining methods because of their brittle, soft, and anisotropic nature. In this article, the characteristics and machining difficulties of soft-brittle and crystals are presented. Moreover, the latest research progress of novel machining technologies and their applications for softbrittle crystals are introduced by using some representative materials (e.g., potassium dihydrogen phosphate (KDP), cadmium zinc telluride (CZT)) as examples. This article reviews the research progress of soft-brittle crystals processing.

  13. Crystal structure of Sc1.91In1.39Mo15Se19, containing Mo6 and Mo9 clusters

    Directory of Open Access Journals (Sweden)

    Patrick Gougeon

    2015-07-01

    Full Text Available The structure of scandium indium pentadecamolybdenum nonadecaselenide, Sc1.91In1.39Mo15Se19, is isotypic with In2.9Mo15Se19 [Grüttner et al. (1979. Acta Cryst. B35, 285–292]. It is characterized by two cluster units Mo6Sei8Sea6 and Mo9Sei11Sea6 (where i represents inner and a apical atoms that are present in a 1:1 ratio. The cluster units are centered at Wyckoff positions 2b and 2c and have point-group symmetry -3 and -6, respectively. The clusters are interconnected through additional Mo—Se bonds. Sc—Se and In—Se bonds complete the structural set-up. In the title compound, the Sc3+ cations replace the trivalent indium atoms present in In2.9Mo15Se19, and a deficiency is observed at the monovalent indium site. One Mo, one Se and the Sc atom are situated on mirror planes, whereas two other Se atoms and the In atom are situated on threefold rotation axes.

  14. Optical spectra of Dy3+-doped GdVO4 and Ca3Sc2Ge3O12 crystals and evaluation of the Ω2/Ω6 ratio as a quality factor for the classification of Dy3+-activated crystalline hosts

    Science.gov (United States)

    Cavalli, Enrico

    2016-11-01

    The room temperature absorption spectra of Dy3+-doped GdVO4 and Ca3Sc2Ge3O12 crystals have been measured and analysed in the framework of the Judd-Ofelt Theory. The calculated intensity parameters have then been correlated with the intensities of the emission bands in the yellow and blue region. The analysis has then been extended to a number of host lattices using literature data, and a general empirical model has been proposed, correlating the Ω2/Ω6 and the yellow to blue (Y/B) ratio in order to define a criterion for predicting the visible luminescence properties of the Dy-activated crystalline materials.

  15. Radiochemical neutron activation analysis for 36 elements in geological material: Au, Ag, Bi, Br, Cd, Cs, Ge, In, Ir, Ni, Os, Pd, Rb, Re, Sb, Se, Sn, Te, Tl, U, and Zn as well as Sc, Y, and REE

    Energy Technology Data Exchange (ETDEWEB)

    Anders, E; Wolf, R; Morgan, J W; Ebihara, M; Woodrow, A B; Janssens, M J; Hertogen, J

    1988-01-01

    In lunar and terrestrial rocks and in meteorites, the radiochemical neutron activation method decribed here enables determination of the 21 trace and ultratrace elements Ag, Au, Bi, Br, Cd, Cs, Ga, Ge, In, Ir, Ni, Os, Pd, Rb, Re, Sb, Se, Te, Tl, U, Zn, as well as 13 rare earth elements (REE), Sc and Y. Materials, techniques and procedures are discussed. 81 refs.

  16. A preliminary review of organic materials single crystal growth by the Czochralski technique

    Science.gov (United States)

    Penn, B. G.; Shields, A. W.; Frazier, D. O.

    1988-01-01

    The growth of single crystals of organic compounds by the Czochralski method is reviewed. From the literature it is found that single crystals of benzil, a nonlinear optical material with a d sub 11 value of 11.2 + or - 1.5 x d sub 11 value of alpha quartz, has fewer dislocations than generally contained in Bridgman crystals. More perfect crystals were grown by repeated Czochralski growth. This consists of etching away the defect-containing portion of a Czochralski grown crystal and using it as a seed for further growth. Other compounds used to grow single crystals are benzophenone, 12-tricosanone (laurone), and salol. The physical properties, growth apparatus, and processing conditions presented in the literature are discussed. Moreover, some of the possible advantages of growing single crystals of organic compounds in microgravity to obtain more perfect crystals than on Earth are reviewed.

  17. Concomitant crystallization for in situ encapsulation of organic materials

    NARCIS (Netherlands)

    Reus, M.A.; Hoetmer, G.; Heijden, A.E.D.M. van der; Horst, J.H. ter

    2014-01-01

    Concomitant crystallization leads to process intensification through the synergistic combination of the partial processes of particle formation and encapsulation within a single process step. Both cooling and electrospray crystallization in multi-component solutions were used to create (sub-)micron

  18. Concomitant crystallization for in situ encapsulation of organic materials

    NARCIS (Netherlands)

    Reus, M.A.; Hoetmer, G.; Heijden, A.E.D.M. van der; Horst, J.H. ter

    2014-01-01

    Concomitant crystallization leads to process intensification through the synergistic combination of the partial processes of particle formation and encapsulation within a single process step. Both cooling and electrospray crystallization in multi-component solutions were used to create (sub-)micron

  19. Crystal growth and comparison of vibrational and thermal properties of semi-organic nonlinear optical materials

    Indian Academy of Sciences (India)

    S Gunasekaran; G Anand; R Arun Balaji; J Dhanalakshmi; S Kumaresan

    2010-10-01

    Single crystals of urea thiourea mercuric sulphate (UTHS) and urea thiourea mercuric chloride (UTHC), semi-organic nonlinear optical materials, were grown by low-temperature solution growth technique by slow evaporation method using water as the solvent. Good quality single crystals were grown within three weeks. The nonlinear nature of the crystals was confirmed by SHG test. The UV–Vis spectrum showed the transmitting ability of the crystals in the entire visible region. FTIR spectrum was recorded and vibrational assignments were made. The degree of dopant inclusion was ascertained by AAS. The TGA–DTA studies showed the thermal properties of the crystals.

  20. Thermal and Mechanical Properties of a Complex Nonlinear Optical Material: Cadmium Mercury Thiocyanate Crystal

    Institute of Scientific and Technical Information of China (English)

    YUAN Duo-Rong; XU Dong; ZHANG Guang-Hui; LIU Ming-Guo; GUO Shi-Yi; MENG Fan-Qing; LU Meng-Kai; FANG Qi; JIANG Min-Hua

    2000-01-01

    Institute of Crystal Materials and State Key Laboratory of Crystal Materials, Shandong University, Ji'nan 250100 (Received 18 March 2000) The data of the thermal expansion and specific heat of cadmium mercury thiocyanate crystal have been obtained. The specific heat is 0.7588J/g℃ at room temperature. The thermal expansion occurs in the direction parallel to the c-axis, and the thermal contraction occurs in the direction parallel to the a-axis. The thermal expansion is the same as the thermal contraction at 353 K. The relationship between thermal properties and crystal structure is discussed.

  1. The peculairities of material crystallization experiments in the CF-18 centrifuge under high gravity

    Science.gov (United States)

    Burdin, B. V.; Regel, L. L.; Turchaninov, A. M.; Shumaev, O. V.

    1992-04-01

    This paper presents data on the crystallization of various materials using the CF-18 centrifuge at the Gagarin Cosmonaut Center. The geometry and equipment are described. Consideration is given to some peculiarities of preparing and conducting crystal growth experiments in this centrifuge. Vibration in a coordinate system fixed to the crystal growth equipment and the reasons for its initiation are shown. From the results of experiments conducted during the last 10 years, it was concluded that there are many possibilities of using various classes of model materials to study crystal growth processes under high gravity conditions.

  2. Effect of crystal structure and cationic order on phonon modes across ferroelectric phase transformation in Pb(Fe{sub 0.5-x}Sc{sub x}Nb{sub 0.5})O{sub 3} bulk ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Mallesham, B.; Ranjith, R., E-mail: ranjith@iith.ac.in [Department of Materials Science and Metallurgical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy - 502285, Telangana (India); Viswanath, B. [School of Engineering, Indian Institute of Technology Mandi, 175001, Himachal Pradesh (India)

    2016-01-15

    Pb(Fe{sub 0.5-x}Sc{sub x}Nb{sub 0.5})O{sub 3} [(PFSN) (0 ≤ x ≤ 0.5)] multiferroic relaxors were synthesized and the temperature dependence of phonon modes across ferroelectric to paraelectric transition was studied. With varying Sc content from x = 0 to 0.25 the structure remains monoclinic and with further addition (x = 0.3 - 0.5) the structure transforms into rhombohedral symmetry. Structural refinement studies showed that the change in crystal structure from monoclinic to rhombohedral symmetry involves a volume increment of 34-36%. Associated changes in the tolerance factor (1.024 ≤ t ≤ 0.976) and bond angles were observed. Structure assisted B′-B″ cation ordering was confirmed through the superlattice reflections in selected area electron diffraction (SAED) pattern of Pb(Sc{sub 0.5}Nb{sub 0.5})O{sub 3} (x = 0.5). Cation ordering is also evident from the evolution of Pb-O phonon mode in Raman spectra of compositions with rhombohedral symmetry (x ≥ 0.3). The high temperature Raman scattering studies show that the B-localized mode [F{sub 1u}, ∼250 cm{sup −1}] and BO{sub 6} octahedral rotational mode [F{sub 1g}, ∼200 cm{sup −1}], both originating from polar nano regions (PNRs) behave like coupled phonon modes in rhombohedral symmetry. However, in monoclinic symmetry they behave independently across the transition. Softening of B localized mode across the transition followed by the hardening for all compositions confirms the diffusive nature of the ferroelectric transformation. The presence of correlation between the B localized and BO{sub 6} rotational modes introduces a weak relaxor feature for systems with rhombohedral symmetry in PFSN ceramics, which was confirmed from the macroscopic dielectric studies.

  3. Synthesis, Crystal Structure, and Characterization of a New Organic-Inorganic Hybrid Material:

    OpenAIRE

    Hela Ferjani; Habib Boughzala; Ahmed Driss

    2013-01-01

    The title compound is an organic-inorganic hybrid material. The single crystal X-ray diffraction investigation reveals that the studied compound crystallizes in the orthorhombic system, space group Pbca with the following lattice parameters:  (4) Å,  (3) Å,  (6) Å, and . The crystal lattice is composed of a discrete anion surrounded by piperazinium cations, chlorine anions, and water molecules. Complex hydrogen bonding interactions between , , organic cations, and water molecules form a thre...

  4. Synthesis and Crystal Structure of a Molybdenum Carbonyl Compound with Thiolate and Dithiocarbamate Ligands,[Bu4N][(OC)4Mo(μ-SC6H5)2Mo(C5H10CNS2)(CO)2

    Institute of Scientific and Technical Information of China (English)

    ZHUANG Bo-Tao; PAN Guo-Hua; ZHOU Zhang-Feng; HE Ling-Jie; Wu Ke-Chen

    2006-01-01

    A di-molybdenum carbonyl compound containing thiolate and dithiocarbamate li- gands, [Bu4N][(CO)4Mo(μ-SC6H5)2Mo(C5H10dtc)(CO)2] 1 (C5H10dtc = S2CNC5H10), has been pre- pared by reaction of [Mo2(SC6H5)2(CO)8] with C5H10dtcNa and [NBu4]Br in acetone. It crystallizes in monoclinic, space group P21/n with a = 13.162(3), b = 17.466(2), c = 20.453(4)(A),β = 100.77(1)°, Z = 4, V = 4619(2)(A)3, C40H56Mo2N2O6S4, Mr = 980.95, Dc = 1.389 g/cm3, μ= 7.66 cm-1, F(000) = 1988 and R = 0.0746 for 5161 observed reflections with I > 2σ(I). The complex contains a [Mo2S2]2- planar core in which one Mo atom is chelated by a C5H10dtc ligand, leading to different coordination environments of the two Mo atoms. 95Mo NMR measurement indicates that the two Mo atoms are in different oxidation states.

  5. Research on Crystal and Film Ferroelectric Materials for Optoelectronic Applications.

    Science.gov (United States)

    1988-03-01

    2 P2 2 P6 + a13 3(P + P 3)P3 + a123rlr2r3 + a 3 3 3 P3 + 1( 1 P2 +c1122P1P2 4 444+ 01 13 1 + P 2 )p + 112 P31 1133( 13333 where the a,’s have been...ratio for C3:C3f is predicted in the low-temperature limit (P 3 large), compared to the - 9:1 ratio measured. Adiabatic vs iso - thermal considerations can...calculated from Eq. (21) using the value of 13333 given above. r 71 C91 I7A/jbs 0 % Rockwell International Science Center SC5345.AR 600 SONI 60 500

  6. Liquid crystals. Oligomeric and polymeric materials for soft photonic technologies

    CERN Document Server

    Coles, M J

    2002-01-01

    The current pace of today's information technologies might lead the casual observer to believe that this is all new. However the reality is that, as with most things, this is really a long evolution of processes based on tried, tested and re-adapted techniques. This thesis represents 12 years of predominantly technology driven research and covers a whole range of characterising, evaluating and fabricating devices based on liquid crystalline systems. Firstly polymer liquid crystals are discussed with respect to the fabrication of a flexible substrate display based on standard printing techniques and this is shown to have improved display viewing properties over a standard polymer dispersed liquid crystal (PDLC) device. Following on from this work is presented that involves the production of regular grid arrays in isotropic polymers that are used as control structures in nematic liquid crystal systems. This progresses onto a now patented device that allows the production of robust ferroelectric devices based on...

  7. Crystal growth of an organic non-linear optical material from the vapour phase

    CERN Document Server

    Hou, W

    1999-01-01

    Due to the potential applications of organic non-linear optical materials in the areas of optical processing and communication, the investigation of the crystal growth of new organic NLO materials has been an active field for the last 20 years. For such uses it is necessary to produce single crystals of high quality and perfection, free of strain and defects. When crystals are grown from the solution and the melt, solvent and the decomposition component in the melt can introduce impurities and imperfection to the as-grown crystals. For crystals grown from vapour phase, in the absence of the solvent, this cannot occur and the method promises to yield single crystals of higher quality. Despite this attraction, little attention has been paid to the vapour phase growth of organic NLO crystals. It was with this in mind that the following investigation was carried out. Using Methyl p-hydroxybenzoate (p-MHB), a potential organic NLO material, a comparison investigation was made of its crystal growth from both the va...

  8. Phase field crystal study of deformation and plasticity in nanocrystalline materials.

    Science.gov (United States)

    Stefanovic, Peter; Haataja, Mikko; Provatas, Nikolas

    2009-10-01

    We introduce a modified phase field crystal (MPFC) technique that self-consistently incorporates rapid strain relaxation alongside the usual plastic deformation and multiple crystal orientations featured by the traditional phase field crystal (PFC) technique. Our MPFC formalism can be used to study a host of important phase transformation phenomena in material processing that require rapid strain relaxation. We apply the MPFC model to study elastic and plastic deformations in nanocrystalline materials, focusing on the "reverse" Hall-Petch effect. Finally, we introduce a multigrid algorithm for efficient numerical simulations of the MPFC model.

  9. Crystal growth and characterizations of L-cystine dihydrobromide—A semiorganic nonlinear optical material

    Science.gov (United States)

    Anbuchezhiyan, M.; Ponnusamy, S.; Muthamizhchelvan, C.

    2010-02-01

    Single crystal of a new semiorganic nonlinear optical material, L-cystine dihydrobromide, was grown successfully from aqueous solution by slow evaporation method. The grown crystals were characterized by single crystal X-ray diffraction technique to determine the cell parameters. Powder X-ray diffraction analysis also confirms the structure of the grown title compound. The functional groups and vibrational frequencies have been identified using FTIR and FT Raman spectral data. Transmittance of the title compound was analyzed using UV-Vis spectrum. The mechanical strength of the grown crystal was found using Vickers microhardness measurement. The thermal stability of the grown crystal was determined with the aid of thermogravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). Second order nonlinear optical behavior of the grown crystal has been confirmed by Kurtz powder second harmonic generation (SHG) test and its SHG efficiency was found as deff=0.38 deff (KDP).

  10. Crystal growth and characterizations of L-cystine dihydrobromide-A semiorganic nonlinear optical material

    Energy Technology Data Exchange (ETDEWEB)

    Anbuchezhiyan, M. [Department of Physics, Valliammai Engineering College, S.R.M. Nagar, Kattankulathur 603 203, Chennai (India); Ponnusamy, S., E-mail: suruponnus@gmail.co [Centre for Material Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603 203, Chennai (India); Muthamizhchelvan, C. [Centre for Material Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603 203, Chennai (India)

    2010-02-15

    Single crystal of a new semiorganic nonlinear optical material, L-cystine dihydrobromide, was grown successfully from aqueous solution by slow evaporation method. The grown crystals were characterized by single crystal X-ray diffraction technique to determine the cell parameters. Powder X-ray diffraction analysis also confirms the structure of the grown title compound. The functional groups and vibrational frequencies have been identified using FTIR and FT Raman spectral data. Transmittance of the title compound was analyzed using UV-Vis spectrum. The mechanical strength of the grown crystal was found using Vickers microhardness measurement. The thermal stability of the grown crystal was determined with the aid of thermogravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). Second order nonlinear optical behavior of the grown crystal has been confirmed by Kurtz powder second harmonic generation (SHG) test and its SHG efficiency was found as d{sub eff}=0.38d{sub eff} (KDP).

  11. S-C Mylonites

    NARCIS (Netherlands)

    Lister, G.S.; Snoke, A.W.

    1984-01-01

    Two types of foliations are commonly developed in mylonites and mylonitic rocks: (a) S-surfaces related to the accumulation of finite strain and (b) C-surfaces related to displacement discontinuities or zones of relatively high shear strain. There are two types of S-C mylonites. Type I S-C mylonites

  12. Reversible crystal-to-amorphous-to-crystal phase transition and a large magnetocaloric effect in a spongelike metal organic framework material.

    Science.gov (United States)

    Tian, Chong-Bin; Chen, Rui-Ping; He, Chao; Li, Wei-Jin; Wei, Qi; Zhang, Xu-Dong; Du, Shao-Wu

    2014-02-21

    Reversible crystal-to-amorphous-to-crystal phase transition accompanied by changes in magnetic and NLO properties was first observed in a rigid non-porous spongelike MOF material. The crystal phase exhibits a high magnetocaloric effect, while the amorphous phase has potential application as a magnetic DMF sensor.

  13. Dynamic Photonic Materials Based on Liquid Crystals (Postprint)

    Science.gov (United States)

    2013-09-01

    in liquid-crystalline side chain polymers. Liquid Crystals, 33, 1421–1427. Atkins , P.W. (1987). Physical chemistry . Oxford: Oxford University Press...unlimited. 22 Luciano De Sio et al. Figure 15 Spectral shape and position of a variety of reflection grating samples written with appropriate chemistries ...gratings written with acrylate chemistry . The scale bar corresponds to 40 nm, 150 nm, and 1500 nm from left to right. The images clearly show the two

  14. Crystallization Behavior of Phosphate Glasses with Hydrophobic Coating Materials

    Directory of Open Access Journals (Sweden)

    Jaeyeop Chung

    2015-01-01

    Full Text Available We analyzed the effect of the addition of Li2O3, TiO2, and Fe2O3 on the crystallization behavior of P2O5–CaO–SiO2–K2O glasses and the effect of the crystallization behavior on the roughness and hydrophobicity of the coated surface. Exothermic behavior, including a strong exothermic peak in the 833–972 K temperature range when Fe2O3, TiO2, or Li2O3 was added, was confirmed by differential thermal analysis. The modified glass samples (PFTL1–3 showed diffraction peaks when heated at 1073 and 1123 K for 5 min; the crystallized phase corresponds to Fe3(PO42, that is, graftonite. We confirmed that the intensity of the diffraction peaks increases at high temperatures and with increasing Li2O3 content. In the case of the PFTL3 glass, a Li3Fe2(PO42 phase, that is, trilithium diiron(III tris[phosphate(V], was observed. Through scanning electron microscopy and the contact angles of the surfaces with water, we confirmed that the increase in surface roughness, correlated to the crystallization of the glass frit, increases hydrophobicity of the surface. The calculated values of the local activation energies for the growth of Fe3(PO42 on the PTFL1, PTFL2, and PFTL3 glass were 237–292 kJ mol−1, 182–258 kJ mol−1, and 180–235 kJ mol−1.

  15. Hardness of materials: studies at levels from atoms to crystals

    Institute of Scientific and Technical Information of China (English)

    LI KeYan; XUE DongFeng

    2009-01-01

    Based on the electron-holding energy per unit volume, we extend the concept of hardness to atomic stiffness, ionic stiffness and bond hardness, investigating the nature of material hardness at these three levels. We find that the stiffness of isolated atoms or ions has no direct connection with the hardness of materials, whereas material hardness is directly related to bond hardness, which is es-sentially determined by the electron-holding energy of its constituent chemical bonds per unit volume. We establish a model for identifying the hardness of materials on the basis of bond hardness. This work offers a deeper understanding of the nature of material hardness at the atomic level, and provides a practical guide in the search for new superhard materials.

  16. A novel laser-based method for controlled crystallization in dental prosthesis materials

    Science.gov (United States)

    Cam, Peter; Neuenschwander, Beat; Schwaller, Patrick; Köhli, Benjamin; Lüscher, Beat; Senn, Florian; Kounga, Alain; Appert, Christoph

    2015-02-01

    Glass-ceramic materials are increasingly becoming the material of choice in the field of dental prosthetics, as they can feature both high strength and very good aesthetics. It is believed that their color, microstructure and mechanical properties can be tuned such as to achieve an optimal lifelike performance. In order to reach that ultimate perfection a controlled arrangement of amorphous and crystalline phases in the material is required. A phase transformation from amorphous to crystalline is achieved by a heat treatment at defined temperature levels. The traditional approach is to perform the heat treatment in a furnace. This, however, only allows a homogeneous degree of crystallization over the whole volume of the parent glass material. Here a novel approach using a local heat treatment by laser irradiation is presented. To investigate the potential of this approach the crystallization process of SiO2-Li2O-Al2O3-based glass has been studied with laser systems (pulsed and continuous wave) operating at different wavelengths. Our results show the feasibility of gradual and partial crystallization of the base material using continuous laser irradiation. A dental prosthesis machined from an amorphous glassy state can be effectively treated with laser irradiation and crystallized within a confined region of a few millimeters starting from the body surface. Very good aesthetics have been achieved. Preliminary investigation with pulsed nanosecond lasers of a few hundreds nanoseconds pulse width has enabled more refinement of crystallization and possibility to place start of phase change within the material bulk.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-09

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

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

    Science.gov (United States)

    Tercjak, A.; Garcia, I.; Mondragon, I.

    2008-07-01

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

  19. Directory of crystal growth and solid state materials production and research

    Energy Technology Data Exchange (ETDEWEB)

    Connolly, T.F.; Battle, G.C.; Keesee, A.M. (comps.)

    1979-03-01

    This directory lists only those who returned questionnaires distributed by the Research Materials Information Center during 1978. The directory includes, in addition to crystal growers, those preparing starting materials for crystal growth and ultrapure noncrystalline research specimens. It also includes responses from those characterizing, or otherwise studying, the properties of materials provided by others. The international coverage of the directory is limited to the United States, Argentina, Australia, Bulgaria, Canada, Czechoslovakia, Egypt, Finland, East Germany, Hungary, India, Israel, Japan, Mexico, Poland, Romania, South Africa, Taiwan, Yugoslavia, and Zaire.

  20. Liquid crystal devices based on photoalignment and photopatterning materials

    Science.gov (United States)

    Chigrinov, Vladimir

    2014-02-01

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

  1. Hydride vapor phase epitaxy growth of GaN, InGaN, ScN, and ScAIN

    NARCIS (Netherlands)

    Bohnen, T.

    2010-01-01

    Chemical vapor deposition (CVD); hydride vapor phase epitaxy (HVPE); gallium nitride (GaN); indium gallium nitride (InGaN); scandium nitride (ScN); scandium aluminum nitride (ScAlN); semiconductors; thin films; nanowires; III nitrides; crystal growth - We studied the HVPE growth of different III ni

  2. Computational studies of bioceramic crystals and related materials

    Science.gov (United States)

    Rulis, Paul Michael

    Ongoing research to improve the foundations of knowledge concerning the human body requires a detailed understanding of the effects derived from atomic interactions. The details of these fundamental interactions will pave the way to the effective manipulation of macroscopic tissue. As a small step towards the realization of that goal the Orthogonalized Linear Combination of Atomic Orbitals (OLCAO) program suite has been applied to complex bioceramic crystals and other prototypes of hard tissue biological nanostructures. In addition, the OLCAO program suite has been further developed and extended in terms of efficiency, features, ease of use, and ease of maintenance such that even more complex systems and effects can be treated in the future. Through extensive OLCAO ab initio calculations on a collection of prototype bioceramic crystals the differences between them in terms of bonding, charge transfer, electronic structure, and spectroscopic properties have been detailed in an effort to lay the foundations of further research where interfaces, dopants, and defects are considered. In addition, inactive silicon defects that can be considered as prototypes for the complex environment in which bioceramic apatites exist have also been studied with the OLCAO program suite in an effort to expand the detection limit of small structures through spectroscopic means. With much effort, the OLCAO program suite has undergone a detailed conversion to a more modern programming language and programming style. A thorough review of the source code has accounted for many inaccuracies, corrected some programming errors, and removed various inefficient algorithmic bottlenecks. The generation of OLCAO input files, the execution of the components of the OLCAO suite, and the analysis of resultant data has been automated with numerous control scripts. Various external library packages have been instrumented for the benefit of profiling and resource efficiency in a high performance computing

  3. Li2S@C composite incorporated into 3D reduced graphene oxide as a cathode material for lithium-sulfur batteries

    Science.gov (United States)

    Wang, D. H.; Xie, D.; Yang, T.; Zhong, Y.; Wang, X. L.; Xia, X. H.; Gu, C. D.; Tu, J. P.

    2016-05-01

    Surface conductive engineering on Li2S is critical for construction of advanced cathodes of lithium-sulfur batteries. Herein, we construct a high-performance Li2S-based composite cathode with the help of three-dimensional reduced graphene oxide (3D-rGO) network and outer carbon coating. Typically, the Li2S@C particles are uniformly embedded into 3D-rGO to form a binder-free 3D-rGO-Li2S@C cathode by the combination of a liquid solution-evaporation coating and PVP (Polyvinyl Pyrrolidone) carbonization. The 3D-rGO-Li2S@C cathode exhibits a high initial discharge capacity of 856 mAh g-1 at 0.1C, superior cycling stability with a capacity of 388.4 mAh g-1 after 200 cycles at 1C, corresponding to a low capacity fading rate. It is demonstrated that the outer conductive coating is effective and necessary for electrochemical enhancement of Li2S cathodes by improving electrical conductivity and prohibiting polysulfide from shuttling during cycling.

  4. Glass Formation of a Coordination Polymer Crystal for Enhanced Proton Conductivity and Material Flexibility.

    Science.gov (United States)

    Chen, Wenqian; Horike, Satoshi; Umeyama, Daiki; Ogiwara, Naoki; Itakura, Tomoya; Tassel, Cédric; Goto, Yoshihiro; Kageyama, Hiroshi; Kitagawa, Susumu

    2016-04-18

    The glassy state of a two-dimensional (2D) Cd(2+) coordination polymer crystal was prepared by a solvent-free mechanical milling process. The glassy state retains the 2D structure of the crystalline material, albeit with significant distortion, as characterized by synchrotron X-ray analyses and solid-state multinuclear NMR spectroscopy. It transforms to its original crystal structure upon heating. Thus, reversible crystal-to-glass transformation is possible using our new processes. The glass state displays superior properties compared to the crystalline state; specifically, it shows anhydrous proton conductivity and a dielectric constant two orders of magnitude greater than the crystalline material. It also shows material flexibility and transparency.

  5. In-situ nano-crystal-to-crystal transformation synthesis of energetic materials based on three 5,5′-azotetrazolate Cr(III) salts

    Science.gov (United States)

    Miao, Yu; Qiu, Yanxuan; Cai, Jiawei; Wang, Zizhou; Yu, Xinwei; Dong, Wen

    2016-01-01

    The in-situ nano-crystal-to-crystal transformation (SCCT) synthesis provides a powerful approach for tailoring controllable feature shapes and sizes of nano crystals. In this work, three nitrogen-rich energetic nano-crystals based on 5,5′-azotetrazolate(AZT2−) Cr(III) salts were synthesized by means of SCCT methodology. SEM and TEM analyses show that the energetic nano-crystals feature a composition- and structure-dependent together with size-dependent thermal stability. Moreover, nano-scale decomposition products can be obtained above 500 °C, providing a new method for preparing metallic oxide nano materials. PMID:27869221

  6. In-situ nano-crystal-to-crystal transformation synthesis of energetic materials based on three 5,5'-azotetrazolate Cr(III) salts.

    Science.gov (United States)

    Miao, Yu; Qiu, Yanxuan; Cai, Jiawei; Wang, Zizhou; Yu, Xinwei; Dong, Wen

    2016-11-21

    The in-situ nano-crystal-to-crystal transformation (SCCT) synthesis provides a powerful approach for tailoring controllable feature shapes and sizes of nano crystals. In this work, three nitrogen-rich energetic nano-crystals based on 5,5'-azotetrazolate(AZT(2-)) Cr(III) salts were synthesized by means of SCCT methodology. SEM and TEM analyses show that the energetic nano-crystals feature a composition- and structure-dependent together with size-dependent thermal stability. Moreover, nano-scale decomposition products can be obtained above 500 °C, providing a new method for preparing metallic oxide nano materials.

  7. Evaluation method of multiaxial low cycle fatigue life for cubic single crystal material

    Institute of Scientific and Technical Information of China (English)

    CHEN Jiping; DING Zhiping

    2007-01-01

    The coupling effect of normal stress and shear stress on orthotropic materials happens when applied loading deflects from the directions of the principal axes of the material coordinate system.By taking account of the coupling effects,formulas of equivalent stress and strain for cubic single crystal materials are cited.Using the equivalent strain and equivalent stress for such material and a variable k,which is introduced to express the effect of asymmetrical cyclic loading on fatigue life,a low cycle fatigue (LCF) life prediction model for such material in multiaxial stress starts is proposed.On the basis of the yield criterion and constitutive model of cubic single crystal materials,a subroutine to calculate the thermo elastic-plastic stress-strain of the material on an ANSYS platform was developed.The cyclic stress-strain of DD3 notched specimens under asymmetrical loading at 680℃ was analyzed.Low cycle fatigue test data of the single crystal nickel-based superalloy are used to fit the different parameters of the power law with multiple linear regression analysis.The equivalent stress and strain for a cubic single crystal material as failure parameters have the largest correlation coefficient.A power law exists between k and the failure cycle.The model was validated with LCF test data of CMSX-2 and DD3 single crystal nickel-based superalloys.All the test data fall into the factor of 2.5 for CMSX-2 hollow cylinder specimens and 2.0 scatter band for DD3 notched specimens,respectively.

  8. Reflectance and reflection phase of photonic crystal with anisotropic left-handed materials

    Science.gov (United States)

    Kang, Yongqiang; Zhang, Chunmin; Yao, Baoli

    2016-11-01

    The reflectance and reflection phase properties of one dimensional photonic crystals with anisotropic left-handed materials is investigated by transfer matrix method. It is demonstrated that the width of zero- n band gap is influenced by the incident angle, polarization, the proportion of lattice and the ratio of thickness which is different from the zero- n band gap with isotropic left hand materials. The value of reflection phase is affected by incident angle and polarization and not affected by the proportion of lattice and the ratio of thickness. These characteristic may be useful for making photonic crystal phase compensators and the dispersion compensators.

  9. An Artificially Garnet Crystal Materials Using In Terahertz Waveguide

    Institute of Scientific and Technical Information of China (English)

    YANG Qing-Hui; ZHANG Huai-Wu; LIU Ying-Li; WEN Qi-Ye; ZHA Jie

    2008-01-01

    A hypothesis is brought forward that the materials with low propagation loss in both optical and microwave band may exhibit good performance in terahertz (THz) band because THz wave band interspaces those two wavebands. For the purpose of exploring a kind of low-loss material for THz waveguide, Lu2.1Bio.9FesO12(LuBiIG)garnet films are prepared by liquid phase epitaxy (LPE) method on a gadolinium gallium garnet (GGG) substrate from lead-free flux because of the good properties in both optical and microwave bands. In microwave band, the ferromagnetic resonance (FMR) linewidth of the film 2△H = 2.8-5.1 Oe; in optical band, the optical absorption coefficient is 600cm-1 at visible range and about 100-170cm-l when the wavelength is longer than 80Onm. In THz range, our hypothesis is well confirmed by a THz-TDS measurement which shows that the absorbance of the film for THz wave is 0.05-0.3 cm- 1 and the minimum value appears at 2.3 THz. This artificial ferromagnetic material holds a great promise for magnetic field tunable THz devices such as wavegnide, modulator or switch.

  10. Effects of Sc and Y substitution on the structure and thermoelectric properties of Yb14MnSb11

    Science.gov (United States)

    Grebenkemper, Jason H.; Klemenz, Sebastian; Albert, Barbara; Bux, Sabah K.; Kauzlarich, Susan M.

    2016-10-01

    Yb14MnSb11 is the most efficient bulk p-type thermoelectric material for high temperature applications. Materials with Y and Sc substitutions in Yb14MnSb11 were made both in Sn-flux and by ball milling. These small 3+ rare earth (RE) cations were introduced with the goal of providing chemical pressure on the structure. The RE3+ cation is smaller than Yb2+ and also donates one additional electron to this p-type semiconductor. In Yb14-xRExMnSb11 (RE = Sc, Y) the maximum x was about 0.5. X-ray diffraction experiments on the single crystals obtained from Sn-flux showed that Sc preferentially substitutes for Yb(1) and Yb(3), and decreases the size of the unit cell by about 0.3%. Y substitutes on all Yb sites and increases the size of the unit cell by about 0.2%. Samples with Yb14-xRExMnSb11 (x~0.3) were prepared via powder metallurgy and spark plasma sintering for transport and thermal conductivity measurements. Electron microprobe of the Sc-substituted sample showed small regions (≤1 μ m) containing greater amounts of Sc, and X-ray powder diffraction of the ball milled Sc sample could be fitted as phase pure Yb14-xScxMnSb11. Y-substituted samples showed larger regions of excess Y in electron microprobe, and small amounts of Yb4Sb3 in X-ray powder diffraction. The Sc sample has slightly reduced carrier concentration over optimized Yb14MnSb11, while the Y samples have even lower carrier concentrations. These carrier concentrations lead to comparable resistivity to Yb14MnSb11 in the Sc-substituted material, and higher resistivities in the Y-substituted material. All materials had similar Seebeck coefficients that slightly exceed Yb14MnSb11 at high temperatures, with the Sc-substituted sample having the highest despite having a higher carrier concentration. Sc-substituted samples also had a slightly higher thermal conductivity over the Y-substituted samples, which had comparable thermal conductivity to Yb14MnSb11. The zT values of the Sc and Y substituted samples are

  11. Synthesis, crystal structure, vibrational spectra, optical properties and theoretical investigation of a two-dimensional self-assembled organic-inorganic hybrid material

    Science.gov (United States)

    Dammak, Hajer; Elleuch, Slim; Feki, Habib; Abid, Younes

    2016-11-01

    Organic-inorganic hybrid material of formula (C4H3SC2H4NH3)2[PbI4] was synthesized and studied by X-ray diffraction, Infrared absorption, Raman scattering, UV-Visible absorption and photoluminescence measurements. The molecule crystallizes as an organic-inorganic two-dimensional (2D) structure built up from infinite PbI6 octahedra surrounded by organic cations. Such a structure may be regarded as quantum wells system in which the inorganic layers act as semiconductor wells and the organic cations act as insulator barriers. Room temperature IR and Raman spectra were recorded in the 520-3500 and 10-3500 cm-1 frequency range, respectively. Optical absorption measurements performed on thin films of (C4H3SC2H4NH3)2[PbI4] revealed three distinct bands at 2.4, 2.66 and 3.25 eV. We also report DFT calculations of the electric dipole moments (μ), polarizability (α), the static first hyperpolarizability (β) and HOMO-LUMO analysis of the title compound investigated by GAUSSIAN 09 package. The calculated static first Hyperpolarizability is equal to 11.46 × 10-31 esu.

  12. Modeling of Crystal Orientations in Laser Powder Deposition of Single Crystal Material

    Science.gov (United States)

    Qi, Huan; Liu, Zhaoyang

    This paper presents a numerical model which simulates the dynamic molten pool formation and the crystal orientations of solidified SX alloy in a multi-layer laser powder deposition process. Based on the mathematical model of coaxial laser direct deposition, the effect of parameters (laser power, scanning speed, powder feed rate) on the tendency to form [001] direction expitaxial grains during solidification was evaluated. In the transient three- dimensional model, physical phenomena including heat transfer, melting, grain formation during solidification, mass addition, and fluid flow in the melt pool, were modeled in a self-consistent manner. The temperature fields, fluid flow velocity, clad geometry (width, height and melt pool depth) and grain formation in melting pool of single layer are predicted.

  13. Synthesis, Crystal Structure, and Characterization of a New Organic-Inorganic Hybrid Material:

    Directory of Open Access Journals (Sweden)

    Hela Ferjani

    2013-01-01

    Full Text Available The title compound is an organic-inorganic hybrid material. The single crystal X-ray diffraction investigation reveals that the studied compound crystallizes in the orthorhombic system, space group Pbca with the following lattice parameters:  (4 Å,  (3 Å,  (6 Å, and . The crystal lattice is composed of a discrete anion surrounded by piperazinium cations, chlorine anions, and water molecules. Complex hydrogen bonding interactions between , , organic cations, and water molecules form a three-dimensional network. Room temperature IR, Raman spectroscopy, and optical absorption of the title compound were recorded and analysed. The observed crystal morphology was compared to the simulated one using the Bravais-Friedel, Donnay-Harker model.

  14. Organometallic chemistry meets crystal engineering to give responsive crystalline materials.

    Science.gov (United States)

    Bacchi, A; Pelagatti, P

    2016-01-25

    Dynamically porous crystalline materials have been obtained by engineering organometallic molecules. This feature article deals with organometallic wheel-and-axle compounds, molecules with two relatively bulky groups (wheels) connected by a linear spacer. The wheels are represented by half-sandwich Ru(ii) moieties, while the spacer can be covalent or supramolecular in character. Covalent spacers are obtained using divergent bidentate ligands connecting two [(arene)RuX2] groups. Supramolecular spacers are instead obtained by exploiting the dimerization of COOH or C(O)NH2 groups appended to N-based ligands. A careful choice of ligand functional groups and X ligands leads to the isolation of crystalline materials with remarkable host-guest properties, evidenced by the possibility of reversibly capturing/releasing volatile guests through heterogenous solid-gas reactions. Structural correlations between the crystalline arrangement of the apohost and the host-guest compounds allow us to envisage the structural path followed by the system during the exchange processes.

  15. First principles crystal engineering of nonlinear optical materials. I. Prototypical case of urea

    Science.gov (United States)

    Masunov, Artëm E.; Tannu, Arman; Dyakov, Alexander A.; Matveeva, Anastasia D.; Freidzon, Alexandra Ya.; Odinokov, Alexey V.; Bagaturyants, Alexander A.

    2017-06-01

    The crystalline materials with nonlinear optical (NLO) properties are critically important for several technological applications, including nanophotonic and second harmonic generation devices. Urea is often considered to be a standard NLO material, due to the combination of non-centrosymmetric crystal packing and capacity for intramolecular charge transfer. Various approaches to crystal engineering of non-centrosymmetric molecular materials were reported in the literature. Here we propose using global lattice energy minimization to predict the crystal packing from the first principles. We developed a methodology that includes the following: (1) parameter derivation for polarizable force field AMOEBA; (2) local minimizations of crystal structures with these parameters, combined with the evolutionary algorithm for a global minimum search, implemented in program USPEX; (3) filtering out duplicate polymorphs produced; (4) reoptimization and final ranking based on density functional theory (DFT) with many-body dispersion (MBD) correction; and (5) prediction of the second-order susceptibility tensor by finite field approach. This methodology was applied to predict virtual urea polymorphs. After filtering based on packing similarity, only two distinct packing modes were predicted: one experimental and one hypothetical. DFT + MBD ranking established non-centrosymmetric crystal packing as the global minimum, in agreement with the experiment. Finite field approach was used to predict nonlinear susceptibility, and H-bonding was found to account for a 2.5-fold increase in molecular hyperpolarizability to the bulk value.

  16. Investigation of Sc doped Sr2Fe1.5Mo0.5O6 as a cathode material for intermediate temperature solid oxide fuel cells

    Science.gov (United States)

    Sun, Wang; Li, Peiqian; Xu, Chunming; Dong, Linkun; Qiao, Jinshuo; Wang, Zhenhua; Rooney, David; Sun, Kening

    2017-03-01

    In this work we show that the performance of a Sr2Fe1.5Mo0.5O6 cathode can be improved by scandium substitutional doping. Herein Sr2Fe1.5-xScxMo0.5O6 (SFScxM) compounds are synthesized with a doping value (x) varying from 0 to 0.2, using a glycine-nitrate combustion progress. The phase structure and morphology are characterized by X-ray powder diffraction and scanning electron microscopy showing a perovskite structure and a porous microstructure when doping between 0 and 0.1. X-ray photoelectron spectroscopy results indicate that the Sc-doping has a clear effect on Fe2+/Fe3+ and Mo6+/Mo5+ ratios. On cells consisting of SFScxM electrodes and La0.8Sr0.2Ga0.8Mg0.2O3 electrolytes, Sc doping is found to be very effective in reducing the interfacial polarization resistance. Impedance data analysis of SFSc0.05M cathode at a variety of oxygen partial pressures indicates that the rate limiting steps are the dissociation of adsorbed molecular oxygen for the high-frequency arc and the migration of oxygen ions to the triple phase boundary for the low-frequency arc, respectively. The highest single cell peak power density is obtained with the SFSc0.05M cathode reaching 1.23 W cm-2 at 800 °C. The results suggest that Sc-doping of SFScxM can substantially improve the electrochemical performance.

  17. Photoluminescence Studies of ZnSe Starting Materials and Vapor Grown Bulk Crystals

    Science.gov (United States)

    Su, Ching-Hua; Feth, S.; Wang, Ling Jun; Lehoczky, S. L.

    2001-01-01

    Low-temperature photoluminescence (PL) spectra were measured on ZnSe starting materials provided by various vendors and on bulk crystals grown from these starting materials by physical vapor transport (PVT) to study the effects of purification and contamination during PVT process. The impurity levels in one set of starting material/grown crystal were also measured by glow discharge mass spectroscopy (GDMS). The purification effect of pre-growth heat treatments and the PVT process is evidenced from the GDMS results which showed orders of magnitude reduction in the Li and Na concentration and a factor of 3 reduction in the O content after growth. The PL spectra showed that the strong emissions associated with Li (or Na) in one of the starting materials disappeared after growth. The GDMS results also showed increases in the At and Si contents by orders of magnitude after growth. To evaluate the contamination of the crystal during the high temperature growth process, three growth runs were processed using similar growth parameters but different furnace environments. The PL spectra suggest that the At contamination originated from the fused silica ampoule and that the Inconel cartridge might have been the cause of the broad Cu green and Cu red bands observed in one of the grown crystals.

  18. Process induced disorder in crystalline materials: differentiating defective crystals from the amorphous form of griseofulvin.

    Science.gov (United States)

    Feng, Tao; Pinal, Rodolfo; Carvajal, M Teresa

    2008-08-01

    This research investigates milling induced disorder in crystalline griseofulvin. Griseofulvin was subjected to cryogenic milling for various lengths of time. For comparison, the amorphous form of griseofulvin was also prepared by the quench melt method. Different analytical techniques were used to study the differences between the cryomilled, amorphous and crystalline forms of the drug. Cryogenic milling of griseofulvin progressively reduces the crystallinity of the drug by inducing crystal defects, rather than amorphous materials. Raman analysis provides evidence of structural differences between the two. The differences between the defective crystals produced by milling and the amorphous form are significant enough as to be measurable in their bulk thermal properties. Defective crystals show significant decrease in the heat of fusion as a function of milling time but do not exhibit a glass transition nor recrystallization from the amorphous form. Crystal defects undergo recrystallization upon heating at temperatures well below the glass transition temperature (T(g)) in a process that is separate and completely independent from the crystallization of the amorphous griseofulvin, observed above T(g). Physical mixtures of defective crystals and amorphous drug demonstrate that the thermal events associated with each form persist in the mixtures, unaffected by the presence of the other form.

  19. SC tuning fork

    CERN Multimedia

    The tuning fork used to modulate the radiofrequency system of the synchro cyclotron (SC) from 1957 to 1973. This piece is an unused spare part. The SC was the 1st accelerator built at CERN. It operated from August 1957 until it was closed down at the end of 1990. In the SC the magnetic field did not change with time, and the particles were accelerated in successive pulses by a radiofrequency voltage of some 20kV which varied in frequency as they spiraled outwards towards the extraction radius. The frequency varied from 30MHz to about 17Mz in each pulse. The tuning fork vibrated at 55MHz in vacuum in an enclosure which formed a variable capacitor in the tuning circuit of the RF system, allowing the RF to vary over the appropriate range to accelerate protons from the centre of the macine up to 600Mev at extraction radius. In operation the tips of the tuning fork blade had an amplitude of movement of over 1 cm. The SC accelerator underwent extensive improvements from 1973 to 1975, including the installation of a...

  20. SC2 dee

    CERN Multimedia

    1974-01-01

    Checking the positioning of the dee before its introduction into the vacuum chamber of SC2. The dee is mounted on a large cover plate which also carries the dee liner and the pump manifold. The dummy dee is fixed to the pole faces within the vacuum chamber.

  1. Measurement of (43)Sc and (44)Sc production cross-section with an 18MeV medical PET cyclotron.

    Science.gov (United States)

    Carzaniga, Tommaso Stefano; Auger, Martin; Braccini, Saverio; Bunka, Maruta; Ereditato, Antonio; Nesteruk, Konrad Pawel; Scampoli, Paola; Türler, Andreas; van der Meulen, Nicholas

    2017-11-01

    (43)Sc and (44)Sc are positron emitter radionuclides that, in conjunction with the β(-) emitter (47)Sc, represent one of the most promising possibilities for theranostics in nuclear medicine. Their availability in suitable quantity and quality for medical applications is an open issue and their production with medical cyclotrons represents a scientific and technological challenge. For this purpose, an accurate knowledge of the production cross sections is mandatory. In this paper, we report on the cross section measurement of the reactions (43)Ca(p,n)(43)Sc, (44)Ca(p,2n) (43)Sc, (46)Ti(p,α)(43)Sc, and (44)Ca(p,n)(44)Sc at the Bern University Hospital cyclotron. A study of the production yield and purity performed by using commercially available enriched target materials is also presented. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Wave properties of Fibonacci-sequence photonic crystals containing single-negative materials

    Science.gov (United States)

    Chen, Mei-Soong; Wu, Chien-Jang; Yang, Tzong-Jer; Fuh, Andy Ying-Guey

    2013-08-01

    Electromagnetic wave properties of a Fibonacci-sequence photonic crystal (FSPC) made of single-negative materials are theoretically investigated. It is found that, in the oblique incidence, such a kind of photonic crystal exhibits additional photonic bands or dips in the vicinity of either magnetic plasma frequency or electric plasma frequency. The additional photonic bands or dips corresponding to magnetic plasma frequency occur only for the TE wave, whereas those corresponding to electric plasma frequency occur only for the TM wave. In addition, we find that there exist omnidiretional gaps in such a single-negative FSPC.

  3. Visualization of unidirectional optical waveguide using topological photonic crystals made of dielectric material

    CERN Document Server

    Yang, Yuting; Xu, Tao; Wang, Hai-Xiao; Jiang, Jian-Hua; Hu, Xiao; Hang, Zhi Hong

    2016-01-01

    The introduction of topology unravels a new chapter of physics. Topological systems provide unique edge/interfacial quantum states which are expected to contribute to the development of novel spintronics and open the door to robust quantum computation. Optical systems can also benefit from topology. Engineering locally in real space a honeycomb photonic crystal with double Dirac cone in its photonic dispersion, topology transition in photonic band structure is induced and a pseudospin unidirectional optical channel is created and demonstrated by the backscattering immune electromagnetic transportation. The topological photonic crystal made of dielectric material can pave the road towards steering light propagations and contribute to novel communication technology.

  4. Wave Propagation From Electrons to Photonic Crystals and Left-Handed Materials

    CERN Document Server

    Markos, Peter

    2010-01-01

    This textbook offers the first unified treatment of wave propagation in electronic and electromagnetic systems and introduces readers to the essentials of the transfer matrix method, a powerful analytical tool that can be used to model and study an array of problems pertaining to wave propagation in electrons and photons. It is aimed at graduate and advanced undergraduate students in physics, materials science, electrical and computer engineering, and mathematics, and is ideal for researchers in photonic crystals, negative index materials, left-handed materials, plasmonics, nonlinear effects,

  5. Numerical Research of Materials Crystal Lattice Parameters Based on Rare-Earth Metals

    Directory of Open Access Journals (Sweden)

    Obkhodsky Artem

    2017-01-01

    Full Text Available Geometrical parameters (coordinates and angles of CeO2 crystal lattice by molecular dynamics method are calculated. Calculated parameters of crystal lattice are applied for definition the energy band structure via Hartree-Fock method in an approximation to CO LCAO (crystal orbitals as linear combination of atomic orbitals and using the model of cyclic cluster. Calculated minimum energy band p-d is within the value range of experimental data. Valence band maximum is 4.2 while minimum energy band p-d width is 2.8 eV Quantum-chemical calculations are accelerated by Schwarz inequality and direct inversion method in iterative subspace. The obtained mathematical model is implemented into software package for calculating material properties.

  6. Crystal Growth and Characterization of a New NLO Material: p-Toluidine p-Toluenesulfonate

    Directory of Open Access Journals (Sweden)

    M. Suresh

    2013-01-01

    Full Text Available Single crystals of p-Toluidine p-Toluenesulfonate (PTPT, an organic nonlinear optical (NLO material, have been grown by slow evaporation method at room temperature using ethanol as solvent. The crystal system was confirmed from the single crystal X-ray diffraction analysis. The functional groups were identified using FTIR spectroscopy. UV-Vis-NIR spectrum showed that the UV cut-off wavelength of PTPT occurs at 295 nm and it has insignificant absorption in the wavelength region of 532–800 nm. The SHG efficiency of PTPT was measured by employing Kurtz and Perry powder technique using a Q-switched mode locked Nd: YAG laser emitting 1064 nm for the first time and it was found to be 52% of standard KDP. Thermal and mechanical properties of PTPT were examined by TG/DTA and Vickers microhardness test, respectively.

  7. Graphene liquid crystal retarded percolation for new high-k materials

    Science.gov (United States)

    Yuan, Jinkai; Luna, Alan; Neri, Wilfrid; Zakri, Cécile; Schilling, Tanja; Colin, Annie; Poulin, Philippe

    2015-11-01

    Graphene flakes with giant shape anisotropy are extensively used to establish connectedness electrical percolation in various heterogeneous systems. However, the percolation behaviour of graphene flakes has been recently predicted to be far more complicated than generally anticipated on the basis of excluded volume arguments. Here we confirm experimentally that graphene flakes self-assemble into nematic liquid crystals below the onset of percolation. The competition of percolation and liquid crystal transition provides a new route towards high-k materials. Indeed, near-percolated liquid-crystalline graphene-based composites display unprecedented dielectric properties with a dielectric constant improved by 260-fold increase as compared with the polymer matrix, while maintaining the loss tangent as low as 0.4. This performance is shown to depend on the structure of monodomains of graphene liquid-crystalline phases. Insights into how the liquid crystal phase transition interferes with percolation transition and thus alters the dielectric constant are discussed.

  8. Synthesis of polycrystalline materials of SrW04 and growth of its single crystal

    Institute of Scientific and Technical Information of China (English)

    Fan Jiandong; Zhang Huaijin; Wang Zhengping; Ge Wenwei; Wang Jiyang

    2006-01-01

    The polycrystalline materials of SrWO4 were synthesized by means of a solid phase reaction with analytical purity SrCO3 and WO3 at high temperature.The transparent SrWO4 single crystal with dimension of Φ 22 mm×40 mm has been successfully grown along a-axis by Czochralski method.X-ray powder diffraction results show that the as-grown SrWO4 single crystal belongs to tetragonal system and I41/a space group.The measured density of segregation coefficients of W and Sr elements in SrWO4 single crystal are close to 1 by the X-ray fluorescence method.

  9. A co-crystal between benzene and ethane: a potential evaporite material for Saturn's moon Titan

    Directory of Open Access Journals (Sweden)

    Helen E. Maynard-Casely

    2016-05-01

    Full Text Available Using synchrotron X-ray powder diffraction, the structure of a co-crystal between benzene and ethane formed in situ at cryogenic conditions has been determined, and validated using dispersion-corrected density functional theory calculations. The structure comprises a lattice of benzene molecules hosting ethane molecules within channels. Similarity between the intermolecular interactions found in the co-crystal and in pure benzene indicate that the C—H...π network of benzene is maintained in the co-crystal, however, this expands to accommodate the guest ethane molecules. The co-crystal has a 3:1 benzene:ethane stoichiometry and is described in the space group R\\bar 3 with a = 15.977 (1 Å and c = 5.581 (1 Å at 90 K, with a density of 1.067 g cm−3. The conditions under which this co-crystal forms identify it is a potential that forms from evaporation of Saturn's moon Titan's lakes, an evaporite material.

  10. Synthesis, growth, structure and characterization of chalcone crystal: A novel organic NLO material

    Science.gov (United States)

    Agilandeshwari, R.; Meenatchi, V.; Meenakshisundaram, S. P.

    2016-08-01

    Single crystals of a chalcone, (E)-3-(4-bromophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one (BHP), were grown by the slow evaporation solution growth technique. The structure is elucidated by single-crystal X-ray diffraction analysis and the crystal belongs to the monoclinic system with noncentrosymmetric space group P21. Optical studies reveal that the absorption is minimum in the visible region and the cut-off wavelength is at ∼468 nm. The band-gap energy was estimated by the application of the Kubelka-Munk algorithm. The powder X-ray diffraction pattern reveals the good crystallinity of the as-grown specimen. The vibrational patterns in FT-IR are used to identify the functional groups and thermal studies indicate the stability of the material. The second harmonic generation efficiency (SHG), as estimated by Kurtz and Perry powder technique, reveals the superior nonlinear optical character of this material. Hirshfeld surface analysis is done to quantify the intermolecular interactions, responsible for developing a nonlinear atmosphere. As-grown crystals were further characterized by SEM, NMR, mass spectrometry and elemental analysis.

  11. Electronic structure and magnetism of new scandium-based full Heusler compounds: Sc{sub 2}CoZ (Z = Si, Ge, Sn)

    Energy Technology Data Exchange (ETDEWEB)

    Birsan, A., E-mail: anca_birsan@infim.ro

    2014-06-15

    Highlights: • First principles calculations were performed for Sc{sub 2}CoSi, Sc{sub 2}CoGe and Sc{sub 2}CoSn. • The total magnetic moments are 1μ{sub B}/f.u. at equilibrium lattice constants. • Sc{sub 2}CoSi is fully spin polarized for lattice parameters ranging between 6.21 and 6.56 Å. • Sc{sub 2}CoGe presents a pseudogap formed around Fermi level. • Sc{sub 2}CoSn exhibits a half metallic ferromagnetic character, up to 7.05 Å. - Abstract: First principles FPLAPW calculations were performed in the framework of Density Functional Theory (DFT), to study the electronic structures and magnetic properties for the new full-Heusler compounds: Sc{sub 2}CoZ (Z = Si, Ge, Sn). The investigated materials are stable against decomposition, in ferromagnetic configuration and crystallize in the inverse Heusler structures. The half-metallic properties as function of the variation of unit cell volumes are analysed regarding the fourth main group constituent elements. The electronic structure calculations for Sc{sub 2}CoSi and Sc{sub 2}CoSn show half-metallic characters, with indirect band gaps of 0.544 eV and 0.408 eV at optimised lattice parameters of 6.28 Å and 6.62 Å, respectively. For Sc{sub 2}CoGe compound, the Fermi energy is not pinned inside the energy band gap from minority density of states, neither for unit cell contraction nor for enlargement. The calculated total magnetic moments are 1μ{sub B}/f.u., for all compounds, in agreement with Slater–Pauling rule.

  12. Neural signal recording using microelectrode arrays fabricated on liquid crystal polymer material

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choong Jae; Oh, Seung Jae; Song, Jong Keun; Kim, Sung June

    2004-01-05

    Microelectrode arrays have been developed for simultaneous multi-channel recordings from nervous systems, typically using silicon substrates. However, it has been known that it is difficult to meet the biocompatibility and durability requirements using silicon and other dielectric materials (SiO{sub 2}, Si{sub 3}N{sub 4}), due to environmental moisture and ions. Additional disadvantage of silicon being the rigid material makes it hard to apply these materials in chronic recording situations. Liquid Crystal Polymer (LCP) was recently introduced as a candidate material for electronic packaging purposes. The material acts as efficient barrier against ions and moisture, a desirable feature for a substrate material of microelectrode arrays. In this paper, we report on the neural recording performed using the LCP-based microelectrode arrays. The cell adhesion on the new material was compared very favorably with that using silicon, SiO{sub 2}, or polyimide material. The microelectrode arrays were patterned with Ti (500 Angst)/Au (3500 Angst) on the LCP film and were employed in both stimulation and recording from rat sciatic nerve. The electrical characteristic of the recorded signal was as good as those using other substrate materials, proving this material as an excellent candidate for next generation microelectrode arrays.

  13. Structure, crystal growth, optical and mechanical studies of poly bis (thiourea) silver (I) nitrate single crystal: A new semi organic NLO material

    Science.gov (United States)

    Sivakumar, N.; Kanagathara, N.; Varghese, B.; Bhagavannarayana, G.; Gunasekaran, S.; Anbalagan, G.

    2014-01-01

    A new semi organic non linear optical polymeric crystal, bis (thiourea) silver (I) nitrate (TuAgN) with dimension 8 × 7 × 1.5 mm3 has been successfully grown from aqueous solution by slow evaporation solution technique. Single crystal X-ray diffraction study reveals that the crystal belongs to orthorhombic system with non centrosymmetric space group C2221. The crystalline perfection of the crystal was analyzed by high resolution X-ray diffraction (HRXRD) rocking curve measurements. Functional groups present in the crystal were analyzed qualitatively by infrared and Confocal Raman spectral analysis. Effects due to coordination of thiourea with metal ions were also discussed. Optical absorption study on TuAgN crystal shows the minimum absorption in the entire UV-Vis region and the lower cut off wavelength of TuAgN is found to be 318 nm. Thermal analysis shows that the material is thermally stable up to 180 °C. The mechanical strength and its parameters of the grown crystal were estimated by Vicker's microhardness test. The second harmonic generation (SHG) efficiency of the crystal was measured by Kurtz's powder technique infers that the crystal has nonlinear optical (NLO) efficiency 0.85 times that of KDP.

  14. Band structures tunability of bulk 2D phononic crystals made of magneto-elastic materials

    Directory of Open Access Journals (Sweden)

    J. O. Vasseur

    2011-12-01

    Full Text Available The feasibility of contactless tunability of the band structure of two-dimensional phononic crystals is demonstrated by employing magnetostrictive materials and applying an external magnetic field. The influence of the amplitude and of the orientation with respect to the inclusion axis of the applied magnetic field are studied in details. Applications to tunable selective frequency filters with switching functionnality and to reconfigurable wave-guides and demultiplexing devices are then discussed.

  15. Advancements in the Quantification of the Crystal Structure of ZNS Materials Produced in Variable Gravity

    Science.gov (United States)

    Castillo, Martin

    2016-07-01

    Screens and displays consume tremendous amounts of power. Global trends to significantly consume less power and increase battery life have led to the reinvestigation of electroluminescent materials. The state of the art in ZnS materials has not been furthered in the past 30 years and there is much potential in improving electroluminescent properties of these materials with advanced processing techniques. Self-propagating high temperature synthesis (SHS) utilises a rapid exothermic process involving high energy and nonlinearity coupled with a high cooling rate to produce materials formed outside of normal equilibrium boundaries thus possessing unique properties. The elimination of gravity during this process allows capillary forces to dominate mixing of the reactants which results in a superior and enhanced homogeneity in the product materials. ZnS type materials have been previously conducted in reduced gravity and normal gravity. It has been claimed in literature that a near perfect phases of ZnS wurtzite was produced. Although, the SHS of this material is possible at high pressures, there has been no quantitative information on the actual crystal structures and lattice parameters that were produced in this work. Utilising this process with ZnS doped with Cu, Mn, or rare earth metals such as Eu and Pr leads to electroluminescence properties, thus making this an attractive electroluminescent material. The work described here will revisit the synthesis of ZnS via high pressure SHS and will re-examine the work performed in both normal gravity and in reduced gravity within the ZARM drop tower facility. Quantifications in the lattice parameters, crystal structures, and phases produced will be presented to further explore the unique structure-property performance relationships produced from the SHS of ZnS materials.

  16. Liquid-crystal photonic-band-gap materials the tunable electromagnetic vacuum

    CERN Document Server

    Busch, K

    1999-01-01

    We demonstrate that when an optically birefringent nematic liquid crystal is infiltrated into the void regions of an inverse opal, photonic-band-gap (PBG) material, the resulting composite material exhibits a completely tunable PBG. $9 In particular, the three- dimensional PBG can be completely opened or closed by applying an electric field which rotates the axis of the nematic molecules relative to the inverse opal backbone. Tunable light localization effects may $9 be realized by controlling the orientational disorder in the nematic. (28 refs).

  17. "Negative" Hartman Effect in One-dimentional Photonic Crystals with Negative Refractive Materials

    Institute of Scientific and Technical Information of China (English)

    WANG Ligang; XU Jingping; ZHU ShiYao

    2004-01-01

    @@ The Hartman effect inside the one-dimensional photonic crystals (1DPCS) composed of negative index materials (NIMS) is always and is reversed to the Hartman effect inside the 1DPCS composed of positive index materials (PIMs).By calculating the phases of Fourier components of a pulse accumulated inside the 1DPCs of NIMs and the evolution of the pulse inside the 1DPCs of NIMs, the origin of the negative phase time is explained.The evolution of the electromagnetic fields inside the 1DPCs of NIMs is time reversal with conjugate to that inside the 1DPCs of PIMs for real spectral pulses.

  18. First measurement of the nonlinear coefficient for Gd1-xLux Ca4O(BO3)3 and Gd1-xScxCa4O(BO3)3 crystals

    DEFF Research Database (Denmark)

    Andersen, Martin Thalbitzer; Mortensen, Jesper Liltorp; Germershausen, Sven

    2007-01-01

    -cavity SHG of a CW Ti:Sapphire laser, and the effective nonlinear coefficients were found to be in the range of 0.5 to 0.6 pm/V for the three crystals used. The FWHM temperature acceptance bandwidth was measured to be more than 35 °C using a 6 mm long Gd0.871Lu0.129Ca4O(BO3)3 crystal. A maximum of 115 m......The effective nonlinear coefficient and temperature acceptance bandwidth of three Lu and Sc co-doped GdCa4O(B03)3 type nonlinear crystals were measured. NCPM for SHG in to the blue-UV spectral region can be obtained by controlling the co-dopant concentration. Measurements were based on intra......W at 407.3 nm in a single direction was measured using a 6.5 mm long Gd0.96Sc 0.04CaO(BO3)3 crystal....

  19. Gadolinium scandium germanide, Gd2Sc3Ge4

    Directory of Open Access Journals (Sweden)

    Sumohan Misra

    2009-04-01

    Full Text Available Gd2Sc3Ge4 adopts the orthorhombic Pu5Rh4-type structure. The crystal structure contains six sites in the asymmetric unit: two sites are statistically occupied by rare-earth atoms with Gd:Sc ratios of 0.967 (4:0.033 (4 and 0.031 (3:0.969 (3, one site (.m. symmetry is occupied by Sc atoms, and three distinct sites (two of which with .m. symmetry are occupied by Ge atoms. The rare-earth atoms form two-dimensional slabs with Ge atoms occupying the trigonal-prismatic voids.

  20. Thermoluminescence characterization of Ag-doped Li2 B4 O7 single crystal materials.

    Science.gov (United States)

    Kuralı, D; Ekdal Karalı, E; Kelemen, A; Holovey, V; Can, N; Karalı, T

    2017-08-01

    In this study, the thermoluminescence (TL) characteristics of Ag-doped and undoped lithium tetraborate (Li2 B4 O7 , LTB) materials, grown using the Czochralski method, were reported. The TL properties of LTB:Ag, such as glow curve structure, dose response, fading and reproducibility, were investigated. The glow curve of the Li2 B4 O7 :Ag single crystal consists of four peaks located at approximately 75, 130, 190 and 275°C; in undoped LTB, the single crystal shows a broad glow curve with peaks at 65, 90, 125, 160 and 190°C using a heating rate of 5°C/s in the 50-350°C temperature region. The high temperature peak of Ag-doped sample at 275°C has a nonlinear dose response within the range from 33 mGy to 9 Gy. There is a linear response in the range of 33-800 mGy; after which, a sublinear region appears up to 9 Gy for Ag-doped LTB single crystal. For undoped single crystal, the dose response is supralinear for low doses and linear for the region between 1 and 9 Gy. The thermal fading ratio of the undoped material is almost 60% for the high temperature peak after 7 days. Ag-doped LTB single crystal exhibits different behaviour over a period of 7 days. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Computational materials science aided design of glass ceramics and crystal properties (abstract only).

    Science.gov (United States)

    Mannstadt, Wolfgang

    2008-02-13

    Today's high tech materials have in many cases highly specialized properties and designed functionalities. Materials parameters like high temperature stability, high stiffness and certain optical properties have to be optimized and in many cases an adaptation to given processes is necessary. Many materials are compounds or layered structures. Thus, surface and interface properties need to be considered as well. At the same time to some extent just a few atomic layers sometimes determine the properties of the material, as is well known in semiconductor and other thin film technologies. Therefore, a detailed understanding of the materials properties at the atomic scale becomes more and more important. In addition many high tech materials have to be of high purity or selective dopant concentrations have to be adjusted to fulfill the desired functionality. Modern materials developments successfully use computational materials science to achieve that goal. Improved software tools and continuously growing computational power allow us to predict macroscopic properties of materials on the basis of microscopic/atomic ab initio simulation approaches. At Schott, special materials, in particular glasses and glass ceramics, are produced for a variety of applications. For a glass ceramic all the above mentioned difficulties for materials development arise. The properties of a glass ceramic are determined by the interplay of crystalline phases embedded in an amorphous glass matrix. For materials development the understanding of crystal structures and their properties, surfaces and interface phenomena, and amorphous systems are necessary, likewise. Each by itself is already a challenging problem. Many crystal phases that are grown within the glass matrix do not exist as single crystals or are difficult to grow in reasonable amounts for experimental investigations. The only way to obtain the properties of these crystalline phases is through 'ab initio' simulations in the computer

  2. Design of radial phononic crystal using annular soft material with low-frequency resonant elastic structures

    Science.gov (United States)

    Gao, Nansha; Wu, Jiu Hui; Yu, Lie; Xin, Hang

    2016-10-01

    Using FEM, we theoretically study the vibration properties of radial phononic crystal (RPC) with annular soft material. The band structures, transmission spectra, and displacement fields of eigenmode are given to estimate the starting and cut-off frequency of band gaps. Numerical calculation results show that RPC with annular soft material can yield low-frequency band gaps below 350 Hz. Annular soft material decreases equivalent stiffness of the whole structure effectively, and makes corresponding band gaps move to the lower frequency range. Physical mechanism behind band gaps is the coupling effect between long or traveling wave in plate matrix and the vibrations of corrugations. By changing geometrical dimensions of plate thickness e, the length of silicone rubber h2, and the corrugation width b, we can control the location and width of the first band gap. These research conclusions of RPC structure with annular soft material can potentially be applied to optimize band gaps, generate filters, and design acoustic devices.

  3. Synthesis, crystal growth and characterizations of bis ( l-proline) cadmium iodide: a new semi-organic nonlinear optical material

    Science.gov (United States)

    Boopathi, K.; Jagan, R.; Ramasamy, P.

    2016-07-01

    Novel semi-organic single crystals of bis ( l-proline) cadmium iodide (BLPC) were grown by slow evaporation technique. The crystal structure was determined by single-crystal X-ray diffraction studies. Single-crystal X-ray diffraction study shows that [BLPC] crystallizes in orthorhombic system with space group P212121. 1H NMR and 13C NMR studies were conducted for the grown crystal. Functional groups present in the compound were identified by FTIR spectral studies. The UV-Vis-NIR spectrum was studied to analyse the optical properties of the grown crystals. Thermogravimetric analysis was carried out to study thermal behaviour of the materials. Vickers microhardness measurement was carried out for different loads. Etching studies were carried out using water as etchant. The second harmonic generation efficiency was determined by the Kurtz powder method and it was found to be higher than that of potassium dihydrogen phosphate.

  4. Synthesis, crystal growth and characterization of a chiral compound (triphenylphosphine oxide cadmium iodide): A new semiorganic nonlinear optical material

    Science.gov (United States)

    Santhakumari, R.; Ramamurthi, K.; Stoeckli-Evans, Helen; Hema, R.; Nirmala, W.

    2011-05-01

    Synthesis of semiorganic material, triphenylphosphine oxide cadmium iodide (TPPOCdI), is reported for the first time. Employing the temperature reduction method, a crystal of size 16×7×6 mm 3 was grown from dimethyl sulfoxide (DMSO) solution. Three dimensional crystal structure of the grown crystal was determined by single crystal X-ray diffraction study. The complex crystallizes in the chiral orthorhombic space group P2 12 12 1. FTIR study was carried out in order to confirm the presence of the functional groups. UV-vis-NIR spectral studies show that the crystal is transparent in the wavelength range of 290-1100 nm. The microhardness test was carried out, and the load hardness was measured. Thermogravimetric and differential thermal analyses reveal the thermal stability of the crystal. Second harmonic generation efficiency of the powdered TPPOCdI, tested using Nd: YAG laser, is ∼0.65 times that of potassium dihydrogen orthophosphate.

  5. Low field investigations of single crystal Bi(2212): DC magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, G.; Murphy, S.D.; Bhagat, S.M. (Center for Superconductivity Research and Dept. of Physics and Astronomy, Univ. of Maryland, College Park (USA))

    1989-12-01

    DC Magnetization measurements on micaceous Bi(2212) single crystals suggest that; 1. for T< or approx.25 K the material is a bulk Superconductor (SC), 2. as T is increased, the interlayer coupling weakens, until for T> or approx.55 K the lamina become independent. (orig.).

  6. Theoretical Studies on the Electronic Structures and Properties of Complex Ceramic Crystals and Novel Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ching, Wai-Yim

    2012-01-14

    This project is a continuation of a long program supported by the Office of Basic Energy Science in the Office of Science of DOE for many years. The final three-year continuation started on November 1, 2005 with additional 1 year extension to October 30, 2009. The project was then granted a two-year No Cost Extension which officially ended on October 30, 2011. This report covers the activities within this six year period with emphasis on the work completed within the last 3 years. A total of 44 papers with acknowledgement to this grant were published or submitted. The overall objectives of this project are as follows. These objectives have been evolved over the six year period: (1) To use the state-of-the-art computational methods to investigate the electronic structures of complex ceramics and other novel crystals. (2) To further investigate the defects, surfaces/interfaces and microstructures in complex materials using large scale modeling. (3) To extend the study on ceramic materials to more complex bioceramic crystals. (4) To initiate the study on soft condensed matters including water and biomolecules. (5) To focus on the spectroscopic studies of different materials especially on the ELNES and XANES spectral calculations and their applications related to experimental techniques. (6) To develop and refine computational methods to be effectively executed on DOE supercomputers. (7) To evaluate mechanical properties of different crystals and those containing defects and relate them to the fundamental electronic structures. (8) To promote and publicize the first-principles OLCAO method developed by the PI (under DOE support for many years) for applications to large complex material systems. (9) To train a new generation of graduate students and postdoctoral fellows in modern computational materials science and condensed matter physics. (10) To establish effective international and domestic collaborations with both experimentalists and theorists in materials

  7. Academic Training - Pulsed SC Magnets

    CERN Multimedia

    Françoise Benz

    2006-01-01

    2005-2006 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 2, 3, June 29, 30, 31 May, 1, 2 June 11:00-12:00 - Auditorium, bldg 500 Pulsed SC Magnets by M. Wilson Lecture 1. Introduction to Superconducting Materials Type 1,2 and high temperature superconductors; their critical temperature, field & current density. Persistent screening currents and the critical state model. Lecture 2. Magnetization and AC Loss How screening currents cause irreversible magnetization and hysteresis loops. Field errors caused by screening currents. Flux jumping. The general formulation of ac loss in terms of magnetization. AC losses caused by screening currents. Lecture 3. Twisted Wires and Cables Filamentary composite wires and the losses caused by coupling currents between filaments, the need for twisting. Why we need cables and how the coupling currents in cables contribute more ac loss. Field errors caused by coupling currents. Lecture 4. AC Losses in Magnets, Cooling and Measurement Summary of all loss mech...

  8. Final Technical Report on DE-SC00002460 [Bimetallic or trimetallic materials with structural metal centers based on Mn, Fe or V

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Esther Sans [Stony Brook University; Takeuchi, Kenneth James [Stony Brook University; Marschilok, Amy Catherine [Stony Brook University

    2013-07-26

    Bimetallic or trimetallic materials with structural metal centers based on Mn, Fe or V were investigated under this project. These metal centers are the focus of this research as they have high earth abundance and have each shown success as cathode materials in lithium batteries. Silver ion, Ag{sup +}, was initially selected as the displacement material as reduction of this center should result in increased conductivity as Ag{sup 0} metal particles are formed in-situ upon electrochemical reduction. The in-situ formation of metal nanoparticles upon electrochemical reduction has been previously noted, and more recently, we have investigated the resulting increase in conductivity. Layered materials as well as materials with tunnel or channel type structures were selected. Layered materials are of interest as they can provide 2-dimensional ion mobility. Tunnel or channel structures are also of interest as they provide a rigid framework that should remain stable over many discharge/charge cycles. We describe some examples of materials we have synthesized that demonstrate promising electrochemistry.

  9. Background radioactivity of construction materials, raw substance and ready-made CaMoO4 crystals

    CERN Document Server

    Busanov, O A; Gavriljuk, Yu M; Gezhaev, A M; Kazalov, V V; Kornoukhov, V N; Kuzminov, V V; Moseev, P S; Panasenko, S I; Ratkevich, S S; Yakimenko, S P

    2013-01-01

    The results of measurements of natural radioactive isotopes content in different source materials of natural and enriched composition used for CaMoO4 scintillation crystal growing are presented. The crystals are to be used in the experiment to search for double neutrinoless betas-decay of Mo-100.

  10. Background radioactivity of construction materials, raw substance and ready-made CaMoO4 crystals

    Directory of Open Access Journals (Sweden)

    Busanov O.A.

    2014-01-01

    Full Text Available The results of measurements of natural radioactive isotopes content in different source materials of natural and enriched composition used for CaMoO4 scintillation crystal growing are presented. The crystals are to be used in the experiment to search for neutrinoless double beta decay of 100Mo.

  11. Ultrasensitive Sensing Material Based on Opal Photonic Crystal for Label-Free Monitoring of Transferrin.

    Science.gov (United States)

    Wu, Enqi; Peng, Yuan; Zhang, Xihao; Bai, Jialei; Song, Yanqiu; He, Houluo; Fan, Longxing; Qu, Xiaochen; Gao, Zhixian; Liu, Ying; Ning, Baoan

    2017-02-22

    A new opal photonic crystal (PC) sensing material, allowing label-free detection of transferrin (TRF), is proposed in the current study. This photonic crystal was prepared via a vertical convective self-assembly method with monodisperse microspheres polymerized by methyl methacrylate (MMA) and 3-acrylamidophenylboronic acid (AAPBA). FTIR, TG, and DLS were used to characterize the components and particle size of the monodisperse microspheres. SEM was used to observe the morphology of the PC. The diffraction peak intensity decreases as the TRF concentration increase. This was due to the combination of TRF to the boronic acid group of the photonic crystal. After condition optimization, a standard curve was obtained and the linear range of TRF concentration was from 2 × 10(-3) ng/mL to 200 ng/mL. Measurement of TRF concentration in simulated urine sample was also investigated using the sensing material. The results indicated that the PC provided a cheap, label-free, and easy-to-use alternative for TRF determination in clinical diagnostics.

  12. Pyrolysis characteristics and pyrolysis products separation for recycling organic materials from waste liquid crystal display panels

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruixue; Xu, Zhenming, E-mail: zmxu@sjtu.edu.cn

    2016-01-25

    Highlights: • Pyrolysis characteristics are conducted for a better understanding of LCDs pyrolysis. • Optimum design is developed which is significant to guide the further industrial process. • Acetic acid and TPP are recycled and separated. - Abstract: Waste liquid crystal display (LCD) panels mainly contain inorganic materials (glass substrate with indium-tin oxide film), and organic materials (polarizing film and liquid crystal). The organic materials should be removed beforehand since the organic matters would hinder the indium recycling process. In the present study, pyrolysis process is used to remove the organic materials and recycle acetic as well as and triphenyl phosphate (TPP) from waste LCD panels in an environmental friendly way. Several highlights of this study are summarized as follows: (i) Pyrolysis characteristics and pyrolysis kinetics analysis are conducted which is significant to get a better understanding of the pyrolysis process. (ii) Optimum design is developed by applying Box–Behnken Design (BBD) under response surface methodology (RSM) for engineering application which is significant to guide the further industrial recycling process. The oil yield could reach 70.53 wt% and the residue rate could reach 14.05 wt% when the pyrolysis temperature is 570 °C, nitrogen flow rate is 6 L min{sup −1} and the particle size is 0.5 mm. (iii) Furthermore, acetic acid and TPP are recycled, and then separated by rotary evaporation, which could reduce the consumption of fossil energy for producing acetic acid, and be reused in electronics manufacturing industry.

  13. Pyrolysis characteristics and pyrolysis products separation for recycling organic materials from waste liquid crystal display panels.

    Science.gov (United States)

    Wang, Ruixue; Xu, Zhenming

    2016-01-25

    Waste liquid crystal display (LCD) panels mainly contain inorganic materials (glass substrate with indium-tin oxide film), and organic materials (polarizing film and liquid crystal). The organic materials should be removed beforehand since the organic matters would hinder the indium recycling process. In the present study, pyrolysis process is used to remove the organic materials and recycle acetic as well as and triphenyl phosphate (TPP) from waste LCD panels in an environmental friendly way. Several highlights of this study are summarized as follows: (i) Pyrolysis characteristics and pyrolysis kinetics analysis are conducted which is significant to get a better understanding of the pyrolysis process. (ii) Optimum design is developed by applying Box-Behnken Design (BBD) under response surface methodology (RSM) for engineering application which is significant to guide the further industrial recycling process. The oil yield could reach 70.53 wt% and the residue rate could reach 14.05 wt% when the pyrolysis temperature is 570 °C, nitrogen flow rate is 6 L min(-1) and the particle size is 0.5 mm. (iii) Furthermore, acetic acid and TPP are recycled, and then separated by rotary evaporation, which could reduce the consumption of fossil energy for producing acetic acid, and be reused in electronics manufacturing industry. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Structural Analysis of Layered Polymer Crystals and Application to Photofunctional Materials Using Organic Intercalation

    Institute of Scientific and Technical Information of China (English)

    Shinya Oshita; Akikazu Matsumoto

    2005-01-01

    @@ 1Introduction We reported that layered polymer crystals are obtained by the topochemical polymerization of 1,3-diene monomers and provided as host material for organic intercalation[1]. For intercalation using various long-alkyl amines as the guest species, its reaction behavior, mechanism, characteristics, and potential to application have been clarified[2]. We also succeeded in the synthesis of several host layered polymer crystals with different tacticities and layer structures[3]. We describe here intercalation using various stereoregular poly(muconic acid)s (PMA) and n-alkylamines as the host and guest compounds, respectively. The reaction behavior and the layered structure of the obtained ammonium polymers are discussed from the viewpoint of stereochemical structure of the host polymers.

  15. Two anionically derivatized scandium oxoselenates(IV): ScF[SeO3] and Sc2O2[SeO3

    Science.gov (United States)

    Greiner, Stefan; Chou, Sheng-Chun; Schleid, Thomas

    2017-02-01

    Scandium fluoride oxoselenate(IV) ScF[SeO3] and scandium oxide oxoselenate(IV) Sc2O2[SeO3] could be synthesized through solid-state reactions. ScF[SeO3] was obtained phase-pure, by reacting mixtures of Sc2O3, ScF3 and SeO2 (molar ratio: 1:1:3) together with CsBr as fluxing agent in corundum crucibles embedded into evacuated glassy silica ampoules after firing at 700 °C for seven days. Sc2O2[SeO3] first emerged as by-product during the attempts to synthesize ScCl[SeO3] following aforementioned synthesis route and could later be reproduced from appropriate Sc2O3/SeO3 mixtures. ScF[SeO3] crystallizes monoclinically in space group P21/m with a=406.43(2), b =661.09(4), c=632.35(4) pm, β=93.298(3)° and Z=2. Sc2O2[SeO3] also crystallizes in the monoclinic system, but in space group P21/n with a=786.02(6), b=527.98(4), c=1086.11(8) pm, β=108.672(3)° for Z=4. The crystal structures of both compounds are strongly influenced by the stereochemically active lone pairs of the ψ1-tetrahedral [SeO3]2- anions. They also show partial structures, where the derivatizing F- or O2- anions play an important role. For ScF[SeO3] chains of the composition 2+ ∞ 1[FSc2/2] form from connected [FSc2]5+ dumbbells, while [OSc3]7+ pyramids and [OSc4]10+ tetrahedra units are condensed to layers according to 2+ ∞ 2[O2Sc2 ] in Sc2O2[SeO3].

  16. Shock response of single crystal and nanocrystalline pentaerythritol tetranitrate: Implications to hotspot formation in energetic materials.

    Science.gov (United States)

    Cai, Y; Zhao, F P; An, Q; Wu, H A; Goddard, W A; Luo, S N

    2013-10-28

    We investigate shock response of single crystal and nanocrystalline pentaerythritol tetranitrate (PETN) with a coarse-grained model and molecular dynamics simulations, as regards mechanical hotspot formation in the absence or presence of grain boundaries (GBs). Single crystals with different orientations, and columnar nanocrystalline PETN with regular hexagonal, irregular hexagonal, and random GB patterns, are subjected to shock loading at different shock strengths. In single crystals, shock-induced plasticity is consistent with resolved shear stress calculations and the steric hindrance model, and this deformation leads to local heating. For regular-shaped hexagonal columnar nanocrystalline PETN, different misorientation angles lead to activation of different/same slip systems, different deformation in individual grains and as a whole, different GB friction, different temperature distributions, and then, different hotspot characteristics. Compared to their regular-shaped hexagonal counterpart, nanocrystalline PETN with irregular hexagonal GB pattern and that with random GBs, show deformation and hotspot features specific to their GBs. Driven by stress concentration, hotspot formation is directly related to GB friction and GB-initiated crystal plasticity, and the exact deformation is dictated by grain orientations and resolved shear stresses. GB friction alone can induce hotspots, but the hotspot temperature can be enhanced if it is coupled with GB-initiated crystal plasticity, and the slip of GB atoms has components out of the GB plane. The magnitude of shearing can correlate well with temperature, but the slip direction of GB atoms relative to GBs may play a critical role. Wave propagation through varying microstructure may also induce differences in stress states (e.g., stress concentrations) and loading rates, and thus, local temperature rise. GB-related friction and plasticity induce local heating or mechanical hotspots, which could be precursors to chemical

  17. A review of recent theoretical studies in nonlinear crystals: towards the design of new materials

    Science.gov (United States)

    Luppi, Eleonora; Véniard, Valérie

    2016-12-01

    Nonlinear optics is an important and exciting field of fundamental and applied research, with applications in many different disciplines such as physics chemistry, material science and biology. In the recent years, nonlinear optical phenomena started to be also widely used in technological applications for optoelectronics and photovoltaics. This coincided with an important experimental and theoretical search for new materials with an efficient and exploitable nonlinear optical response. Here, starting from the discovery of nonlinear optics, we review the most important theoretical formalisms developed to understand, interpret and predict the nonlinear optical phenomena. We show the different level of approximation of the many-electrons interactions that these formalisms can describe which are fundamental in the interpretation of the experiments. The impact of the theory is then analyzed on different classes of new materials particularly studied in these years: silicon bulk to nano, compound semiconductors, graphene, transition metal dichalcogenide, hexagonal boron nitride and borate crystals.

  18. A Novel Approach to Obtain GeSbTe-Based High Speed Crystallizing Materials for Phase Change Optical Recording

    Science.gov (United States)

    2001-04-01

    UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP012318 TITLE: A Novel Approach to Obtain GeSbTe -Based High Speed...UNCLASSIFIED Mat. Res. Soc. Symp. Proc. Vol. 674 © 2001 Materials Research Society A Novel Approach to Obtain GeSbTe -Based High Speed Crystallizing...fast crystallizing materials based on a conventional GeSbTe alloy for rewritable phase change optical data storage. By means of co-sputtering

  19. The Influence of Reduced Gravity on the Crystal Growth of Electronic Materials

    Science.gov (United States)

    Su, Ching-Hua; Gillies, D. C.; Szofran, F. R.; Watring, D. A.; Lehoczky, S. L.

    1996-01-01

    The imperfections in the grown crystals of electronic materials, such as compositional nonuniformity, dopant segregation and crystalline structural defects, are detrimental to the performance of the opto-electronic devices. Some of these imperfections can be attributed to effects caused by Earth gravity during crystal growth process and four areas have been identified as the uniqueness of material processing in reduced gravity environment. The significant results of early flight experiments, i.e. prior to space shuttle era, are briefly reviewed followed by an elaborated review on the recent flight experiments conducted on shuttle missions. The results are presented for two major growth methods of electronic materials: melt and vapor growth. The use of an applied magnetic field in the melt growth of electrically conductive melts on Earth to simulate the conditions of reduced gravity has been investigated and it is believed that the superimposed effect of moderate magnetic fields and the reduced gravity environment of space can result in reduction of convective intensities to the extent unreachable by the exclusive use of magnet on Earth or space processing. In the Discussions section each of the significant results of the flight experiments is attributed to one of the four effects of reduced gravity and the unresolved problems on the measured mass fluxes in some of the vapor transport flight experiments are discussed.

  20. Spectroscopic and crystal-field analysis of new Yb-doped laser materials

    Energy Technology Data Exchange (ETDEWEB)

    Haumesser, Paul-Henri; Gaume, Romain; Antic-Fidancev, Elisabeth; Vivien, Daniel; Viana, Bruno [Laboratoire de Chimie Appliquee de l' Etat Solide UMR 75 74, ENSCP, Paris (France)]. E-mail: viana@ext.jussieu.fr

    2001-06-11

    Crystal-field effects are very important as far as laser performances of Yb-doped materials are concerned. In order to simplify the interpretation of low-temperature spectra, two tools derived from a careful examination of crystal-field interaction are presented. Both approaches are successfully applied in the case of new Yb-doped materials, namely Ca{sub 3}Y{sub 2}(BO{sub 3}){sub 4} (CYB), Ca{sub 3}Gd{sub 2}(BO{sub 3}){sub 4} (CaGB), Sr{sub 3}Y(BO{sub 3}){sub 3} (SrYBO), Ba{sub 3}Lu(BO{sub 3}){sub 3} (BLuB), Y{sub 2}SiO{sub 5} (YSO), Ca{sub 2}Al{sub 2}SiO{sub 7} (CAS) and SrY{sub 4}(SiO{sub 4}){sub 3}O (SYS). The {sup 2}F{sub 7/2} splitting is particularly large in these materials and favourable to a quasi-three-level laser operating scheme. Calculations performed using the point charge electrostatic model for these compounds and using a consistent set of effective atomic charges confirm the experimental results. This should permit to use this model in a predictive approach. (author)

  1. Tunable photonic band-gaps in one-dimensional photonic crystals containing linear graded index material

    Science.gov (United States)

    Singh, Bipin K.; Kumar, Pawan; Pandey, Praveen C.

    2014-12-01

    We have demonstrated control of the photonic band gaps (PBGs) in 1-D photonic crystals using linear graded index material. The analysis of PBG has been done in THz region by considering photonic crystals in the form of ten periods of second, third and fourth generation of the Fibonacci sequence as unit cell. The unit cells are constituted of two kinds of layers; one is taken of linear graded index material and other of normal dielectric material. For this investigation, we used a theoretical model based on transfer matrix method. We have obtained a large number of PBGs and their bandwidths can be tuned by changing the grading profile and thicknesses of linear graded index layers. The number of PBGs increases with increase in the thicknesses of layers and their bandwidths can be controlled by the contrast of initial and final refractive index of the graded layers. In this way, we provide more design freedom for photonic devices such as reflectors, filters, optical sensors, couplers, etc.

  2. Ultrafast characterization of phase-change material crystallization properties in the melt-quenched amorphous phase.

    Science.gov (United States)

    Jeyasingh, Rakesh; Fong, Scott W; Lee, Jaeho; Li, Zijian; Chang, Kuo-Wei; Mantegazza, Davide; Asheghi, Mehdi; Goodson, Kenneth E; Wong, H-S Philip

    2014-06-11

    Phase change materials are widely considered for application in nonvolatile memories because of their ability to achieve phase transformation in the nanosecond time scale. However, the knowledge of fast crystallization dynamics in these materials is limited because of the lack of fast and accurate temperature control methods. In this work, we have developed an experimental methodology that enables ultrafast characterization of phase-change dynamics on a more technologically relevant melt-quenched amorphous phase using practical device structures. We have extracted the crystallization growth velocity (U) in a functional capped phase change memory (PCM) device over 8 orders of magnitude (10(-10) programmed PCM devices at very high heating rates (>10(8) K/s), which reveals the extreme fragility of Ge2Sb2Te5 in its supercooled liquid phase. Furthermore, these crystallization properties were studied as a function of device programming cycles, and the results show degradation in the cell retention properties due to elemental segregation. The above experiments are enabled by the use of an on-chip fast heater and thermometer called as microthermal stage (MTS) integrated with a vertical phase change memory (PCM) cell. The temperature at the PCM layer can be controlled up to 600 K using MTS and with a thermal time constant of 800 ns, leading to heating rates ∼10(8) K/s that are close to the typical device operating conditions during PCM programming. The MTS allows us to independently control the electrical and thermal aspects of phase transformation (inseparable in a conventional PCM cell) and extract the temperature dependence of key material properties in real PCM devices.

  3. Tunable omnidirectional multichannel filters based on dual-defective photonic crystals containing negative-index materials

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yihang, E-mail: kallenmail@sina.co [School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China)

    2009-04-07

    Multiple defect modes may generate in one-dimensional dual-defective photonic crystals containing negative-index materials. The interference between the two kinds of defect states of the proposed structure is avoided. Therefore, the frequency, frequency interval and number of the defect modes corresponding to different kinds of defects can be tuned independently as desired. These defect modes inside the zero n-bar gap are insensitive to the incident angle. It thus opens a promising way to fabricate omnidirectional multichannel filters with specific channels.

  4. Mechanical model study of relationship of molecular configuration and multiphase in liquid crystal materials

    Institute of Scientific and Technical Information of China (English)

    Ma Heng; Sun Rui-Zhi; Li Zhen-Xin

    2006-01-01

    A mechanical model of liquid crystals (LCs) is applied to study the polymorphism of homologous series of terphenyl compounds. With a semi-experimental molecular orbit method, we calculate the moment of inertia which represents the rotation state to describe the phase transition temperature obtained from experimental data. We propose a novel explanation of the phase sequence or polymorphism of LC materials using the two key parameters, the moment of inertia and critical rotational velocity. The effect of molecular polarity on the appearance of liquid crystalline is also discussed.

  5. Independent Modulation of Omnidirectional Defect Modes in Single-Negative Materials Photonic Crystal with Multiple Defects

    Institute of Scientific and Technical Information of China (English)

    WANG Qiong; YAN Chang-Chun; ZHANG Ling-Ling; CUI Yi-Ping

    2008-01-01

    @@ Single-negative materials based on photonic crystal with multiple defect layers are designed and the free modulation of defect modes is studied. The results show that the multi-defect structure can avoid the interference between the defect states. Therefore, the designed double defect modes in the zero effective-phase gap can be adjusted independently by changing the thickness of different defect layers. In addition, the two tunable defect modes have the omnidirectional characteristics. This multi-defect structure with above-mentioned two advantages has potential applications in modern optical devices such as tunable omnidirectional filters.

  6. Synthesis, crystal growth, structural, spectral, thermal, mechanical, linear and nonlinear optical studies of organic single crystal 4-Iodo 4-nitrostilbene (IONS): A potential NLO material

    Energy Technology Data Exchange (ETDEWEB)

    Dinakaran, Paul M.; Kalainathan, S., E-mail: kalainathan@yahoo.com

    2013-12-16

    An organic nonlinear optical material 4-Iodo 4-nitrostilbene (IONS) has been synthesized and good optical quality single crystal was grown from ethyl methyl ketone solvent by the solution growth technique. Single and powder X-ray diffraction analyses reveals that the grown crystal belongs to monoclinic crystal system with noncentrosymmetric space group ‘P2{sub 1}’ and it has good crystalline nature. Functional groups and molecular structure of the title compound were confirmed by FTIR and {sup 1}H NMR respectively. The UV–Vis–NIR absorption study reveals no absorption in the visible region and the cut-off wavelength was found to be at 412.84 nm, TG/DTA, mass spectral analysis, photoluminescence and microhardness studies have been carried out for the grown crystals and results are discussed in detail. The second harmonic efficiency of the IONS was determined by Kurtz–Perry powder technique which reveals that the IONS crystal (3.1 V) has greater efficiency i.e., 143 times to that of KDP (21.7 mV). - Highlights: • The 4-Iodo 4-nitrostilbene (IONS) material has been synthesized by Wittig reaction. • The single crystal was grown for the first time with dimensions of 9.5 × 4 × 1.5 mm{sup 3}. • SHG efficiency of IONS is 143 times greater than that of KDP crystal. • The UV–Vis absorption study reveals that the transparency was found to be good. • IONS crystal is a potential candidate for optoelectronic applications.

  7. Refractive indices of polymer-dispersed liquid-crystal film materials: Epoxy-based systems

    Science.gov (United States)

    Vaz, Nuno A.; Montgomery, G. Paul, Jr.

    1987-10-01

    Polymer-dispersed liquid crystal (PDLC) films are potentially useful in applications requiring electrically controllable light transmission. In these applications, both a high on-state transmittance and a strong off-state attenuation are often needed over a wide operating temperature range. These transmittance characteristics depend strongly on the refractive indices of the materials in the PDLC films. We have measured the temperature dependent refractive indices of typical PDLC film materials and the temperature dependent electro-optic transmittance of a PDLC film composed of liquid crystal microdroplets dispersed in an epoxy matrix. We show that our refractive index measurements can account for all the features in the measured transmittance characteristics and discuss several methods for controlling refractive indices to optimize electro-optic transmittance over an extended temperature range. We have also measured the room temperature refractive indices of mixtures of epoxy resins and hardeners as a function of composition. We discuss the problems associated with predicting the refractive indices of such mixtures in terms of either the volume fractions or mole fractions of the mixture components. These considerations are important in matching refractive indices of droplets and matrix materials to maximize on-state transmittance. The refractive indices of epoxy matrix materials increase monotonically with time during their chemical cure. The measured time dependence can be described by a simple model in which the concentrations of the reacting resin and hardener each decay exponentially in time with their own characteristic time constants while the concentration of the cured polymer increases. Finally, we relate the measured rates of index change with temperature to the coefficients of volume expansion of PDLC film materials; the results are used to discuss the mechanical stability of PDLC films.

  8. Fluorinated Epoxy Resins-based Sorbent Coating Materials for Quartz Piezoelectric Crystal Detector

    Directory of Open Access Journals (Sweden)

    D. C Gupta

    2004-04-01

    Full Text Available Fluorinated epoxy resins were synthesised and evaluated as sorbent coating materials for the detection of organophosphorus compounds using quartz piezoelectric crystal detector. These resins were prepared by reacting excess of epichlorohydrin with each of or in combination of fluorinated diols, ie, a, a, a', a' tetrakis (trifluoromethyl 1,3 benzene dimethanol (TTFMBD, 4,4'bis-2-hydroxy hexafluoro isopropyl biphenyl (BHHFIBP, 4,4'dihydroxyocta fluorodiphenyl (DHOFDP and 2,2,3,3,4,4 hexafluoro 1,5 pentanediol (HFPD in the presence of sodium hydroxide at reflux temperature. These polymers were extracted in organic solvents and dried. Each of these fluoroepoxy resins were coated over quartz piezoelectric crystal by solution-casting method and tested using dimethylmethyl phosphonate (DMMP as model compound. Change in the  frequency (AF of quartz piezoelectric crystal oscillator was recorded. Sensitive and potential fluorinated epoxy resins, ie, diglycidylethers (DGE of HFPD-TTFMBD (in the molar ratio 6:4 and DGE (HFPD-BHHFIBP in the molar ratio 4:6 were characterised by viscosity, number average molecular weight (Mn, epoxy equivalent, infrared spectroscopy, and thermal stability.

  9. Liquid phase crystallized silicon on glass: Technology, material quality and back contacted heterojunction solar cells

    Science.gov (United States)

    Haschke, Jan; Amkreutz, Daniel; Rech, Bernd

    2016-04-01

    Liquid phase crystallization has emerged as a novel approach to grow large grained polycrystalline silicon films on glass with high electronic quality. In recent years a lot of effort was conducted by different groups to determine and optimize suitable interlayer materials, enhance the crystallographic quality or to improve post crystallization treatments. In this paper, we give an overview on liquid phase crystallization and describe the necessary process steps and discuss their influence on the absorber properties. Available line sources are compared and different interlayer configurations are presented. Furthermore, we present one-dimensional numerical simulations of a rear junction device, considering silicon absorber thicknesses between 1 and 500 µm. We vary the front surface recombination velocity as well as doping density and minority carrier lifetime in the absorber. The simulations suggest that a higher absorber doping density is beneficial for layer thicknesses below 20 µm or when the minority carrier lifetime is short. Finally, we discuss possible routes for device optimization and propose a hybride cell structure to circumvent current limitations in device design.

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

    Science.gov (United States)

    Schadt, Martin

    2009-03-01

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

  11. Hybrid silica luminescent materials based on lanthanide-containing lyotropic liquid crystal with polarized emission

    Energy Technology Data Exchange (ETDEWEB)

    Selivanova, N.M., E-mail: natsel@mail.ru [Kazan National Research Technological University, 68 Karl Marx Str., Kazan 420015 (Russian Federation); Vandyukov, A.E.; Gubaidullin, A.T. [A.E. Arbuzov Institute of Organic and Physical Chemistry of the Kazan Scientific Center of the Russian Academy of Sciences, 8 Acad. Arbuzov Str., Kazan 420088 (Russian Federation); Galyametdinov, Y.G. [Kazan National Research Technological University, 68 Karl Marx Str., Kazan 420015 (Russian Federation)

    2014-11-14

    This paper represents the template method for synthesis of hybrid silica films based on Ln-containing lyotropic liquid crystal and characterized by efficient luminescence. Luminescence films were prepared in situ by the sol–gel processes. Lyotropic liquid crystal (LLC) mesophases C{sub 12}H{sub 25}O(CH{sub 2}CH{sub 2}O){sub 10}H/Ln(NO{sub 3}){sub 3}·6H{sub 2}O/H{sub 2}O containing Ln (III) ions (Dy, Tb, Eu) were used as template. Polarized optical microscopy, X-ray powder diffraction, and FT-IR-spectroscopy were used for characterization of liquid crystal mesophases and hybrid films. The morphology of composite films was studied by the atomic force microscopy method (AFM). The optical properties of the resulting materials were evaluated. It was found that hybrid silica films demonstrate significant increase of their lifetime in comparison with an LLC system. New effects of linearly polarized emission revealed for Ln-containing hybrid silica films. Polarization in lanthanide-containing hybrid composites indicates that silica precursor causes orientation of emitting ions. - Highlights: • We suggest a new simple approach for creating luminescence hybrid silica films. • Ln-containing hybrid silica films demonstrate yellow, green and red emissions. • Tb(III)-containing hybrid film have a high lifetime. • We report effects of linearly polarized emission in hybrid film.

  12. Estimation of diffusion anisotropy in microporous crystalline materials and optimization of crystal orientation in membranes.

    Science.gov (United States)

    Gounaris, Chrysanthos E; First, Eric L; Floudas, Christodoulos A

    2013-09-28

    The complex nature of the porous networks in microporous materials is primarily responsible for a high degree of intracrystalline diffusion anisotropy. Although this is a well-understood phenomenon, little attention has been paid in the literature with regards to classifying such anisotropy and elucidating its effect on the performance of membrane-based separation systems. In this paper, we develop a novel methodology to estimate full diffusion tensors based on the detailed description of the porous network geometry through our recent advances for the characterization of such networks. The proposed approach explicitly accounts for the tortuosity and complex connectivity of the porous framework, as well as for the variety of diffusion regimes that may be experienced by a guest molecule while it travels through the different localities of the crystal. Results on the diffusion of light gases in silicalite demonstrate good agreement with results from experiments and other computational techniques that have been reported in the literature. A comprehensive computational study involving 183 zeolite frameworks classifies these structures in terms of a number of anisotropy metrics. Finally, we utilize the computed diffusion tensors in a membrane optimization model that determines optimal crystal orientations. Application of the model in the context of separating carbon dioxide from nitrogen demonstrates that optimizing crystal orientation can offer significant benefit to membrane-based separation processes.

  13. Er3+/Yb3+共掺Gd3Sc2Ga3O12晶体的上转换发光%Up-conversion luminescence in Er3+/Yb3+-codoped Gd3Sc2Ga3O12 laser crystals

    Institute of Scientific and Technical Information of China (English)

    罗建乔; 孙敦陆; 张庆礼; 刘文鹏; 谷长江; 吴路生; 殷绍唐

    2008-01-01

    研究了提拉法生长的Er3+/Yb3+:Gd3Sc2Ga3O12和Er3+:Gd3Sc2Ga3O12晶体在室温下320-1700 nm范围的吸收光谱和500-750 nm范围内的上转换荧光谱,同时对其上转换荧光的可能发生机制、途径以及上转换过程可能对Er3+的2.8 μm波段激光振荡产生的影响进行了分析和讨论.结果表明:Yb3+的敏化显著地增强了晶体在966 nm附近的吸收能力,大幅度加宽了晶体在该处的吸收带宽.在940 nm激光的激发下,Er3+/Yb3+:Gd3Sc2Ga3O12中的上转换荧光强度明显强于Er3+:Gd3Sc2Ga3O12中的上转换荧光强度,表明Yb3+与Er3+之间存在高效率的能量传递,其主要上转换机制可能为Yb3+-Er3+,Er3+-Er3+能量传递.

  14. Synthesis of Two-Photon Materials and Two-Photon Liquid Crystals

    Science.gov (United States)

    Subramaniam, Girija

    2001-01-01

    The duration of the grant was interrupted by two major accidents that the PI met with-- an auto accident in Pasadena, CA during her second summer at JPL which took almost eight months for recovery and a second accident during Fall 2000 that left her in crutches for the entire semester. Further, the time released agreed by the University was not given in a timely fashion. The candidate has been given post-grant expire time off. In spite of all these problems, the PI synthesized a number of new two-photon materials and studied the structure-activity correlation to arrive at the best-optimized structure. The PI's design proved to be one of the best in the sense that these materials has a hitherto unreported two-photon absorption cross section. Many materials based on PI's design was later made by the NASA colleague. This is Phase 1. Phase II of this grant is to orate liquid crystalline nature into this potentially useful materials and is currently in progress. Recent observations of nano- and pico-second response time of homeotropically aligned liquid crystals suggest their inherent potentials to act as laser hardening materials, i.e., as protective devices against short laser pulses. The objective of the current project is to exploit this potential by the synthesis of liquid crystals with high optical nonlinearity and optimizing their performance. The PI is trying structural variations to bring in liquid crystalline nature without losing the high two-photon cross section. Both Phase I and Phase II led to many invited presentations and publications in reputed journals like 'Science' and 'Molecular Crystals'. The list of presentations and reprints are enclosed. Another important and satisfying outcome of this grant is the opportunity that this grant offered to the budding undergraduate scientists to get involved in a visible research of international importance. All the students had a chance to learn a lot during research, had the opportunity to present their work at

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

    Science.gov (United States)

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

    2015-09-01

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

  16. Evaluation of undoped ZnS single crystal materials for x-ray imaging applications

    Science.gov (United States)

    Saleh, Muad; Lynn, Kelvin G.; McCloy, John S.

    2017-05-01

    ZnS-based materials have a long history of use as x-ray luminescent materials. ZnS was one of the first discovered scintillators and is reported to have one of the highest scintillator efficiencies. The use of ZnS for high energy luminescence has been thus far limited to thin powder screens, such as ZnS:Ag which is used for detecting alpha radiation, due to opacity to its scintillation light, primarily due to scattering. ZnS in bulk form (chemical vapor deposited, powder processed, and single crystal) has high transmission and low scattering compared to powder screens. In this paper, the performance of single crystalline ZnS is evaluated for low energy x-ray (decay time, and low levels of afterglow. We present a trade study which compares the calculated scintillation gain and absolute efficiency for low energy x-rays (<10 keV) comparing thin (<100 μm) ZnS to CsI:Tl, Bi4Ge3O12 (BGO), and Y3Al5O12:Ce (YAG:Ce). The study also gives insight into the spatial resolution of these scintillators. Further, photoluminescence (PL) and PL excitation (PLE) of several undoped ZnS single crystals is compared to their Radioluminescence (RL) spectra. It was found that the ZnS emission wavelength varies on the excitation source energy.

  17. Polyethylene Maleate Copolyesters as Coating Materials for Piezoelectric Quartz Crystal-based Chemical Sensors

    Directory of Open Access Journals (Sweden)

    D. C. Gupta

    2005-10-01

    Full Text Available Polyethylene maleate (PEM was synthesised by direct polycondensation of maleic anhydride and ethylene glycol in toluene under reflux usingp-toluene sulphonic acid as a catalyst. Structure of PEM was further modified by varying nature of diols and acid components, chain length of glycols, incorporation of aromatic and fluorine groups in the chain. Formation of PEM was monitored by gas chromatography. The parameters like degree of polymerisation, number average molecular weight (Mn, and weight average molecular weight (Mw were calculated from the extent of reaction and stoichiometric ratio of the reactants. The number average molecular weight was also determined using Knauer vapour pressure osmometer. Cohesive energy, volume, and solubility parameters of PEM-based copolyesters were calculated by group contribution method. These PEM-based copolyesters’ have been evaluated as sorbent-coating materials for the detection of organ0 phosphorus(OPcompo using dimethylmethylphosphonate (DMMP as model compound and piezoelectric crystal detector. PEMbisphenol A is found to be the most sensitive and potential coating material for the detection of OP compounds using piezoelectric crystal detector. Potential PEM-based copolyesters have been characterised by viscosity, infrared spectroscopy, NMR spectroscopy, Mn and thermal stability.

  18. Effect of homogenizing heatings on the properties of Al-Sc and Al-Mg-Sc alloy systems

    Energy Technology Data Exchange (ETDEWEB)

    Drits, M.E.; Toropova, L.S.; Anastas' eva, G.K.; Nagornichnykh, G.L.

    Effect of annealing on hardness and electric conductivity of cast alloys of Al-Mg-Sc and Al-Sc systems has been studied. Magnesium content in studied alloys was changed in the range of 0-6.5%, scandium content was chosen to be constant -0.4%. It has been revealed that homogenizing heatings of Al-Sc alloys lead to a decomposition of abnormally saturated solid solution during crystallization at temperatures >250 deg C. Maximum hardness values are achieved after annealing at 300 deg C during 1h. Homogenizing of Al-Mg--- Sc alloys at 350 deg C during 24h leads to practically full solubility of a nonequilibrium ..beta..-phase (Mg/sub 2/Al/sub 3/) and also to a decomposition of a solid solution abnormally saturated with scandium. Maximum values of hardness are achieved after annealing at 35O deg C during 0.5-1h.

  19. Metastable Al-Sc phase diagram in aluminium rich region

    Energy Technology Data Exchange (ETDEWEB)

    Drits, M.E.; Toropova, L.S.; Bykov, Yu.G.; Gushchina, F.L.; Elagin, V.I.; Filatov, Yu.A.

    1982-12-01

    An aluminium rich part of binary metastable phase diagram Al-Sc for 100 deg/s alloy cooling rate under crystallization is studied. Eutectic horizontal in the metastable diagram is 4 deg lower as compared to the equilibrium one, scandium concentration in the eutectic point makes up approximately 0.8%, the maximum solubility is 0.6%. Maximum cast grain refining in aluminium under crystallization at the rate of 100 deg/s is attained at 0.6% scandium content.

  20. Organic field-effect transistors using single crystals

    Directory of Open Access Journals (Sweden)

    Tatsuo Hasegawa and Jun Takeya

    2009-01-01

    Full Text Available Organic field-effect transistors using small-molecule organic single crystals are developed to investigate fundamental aspects of organic thin-film transistors that have been widely studied for possible future markets for 'plastic electronics'. In reviewing the physics and chemistry of single-crystal organic field-effect transistors (SC-OFETs, the nature of intrinsic charge dynamics is elucidated for the carriers induced at the single crystal surfaces of molecular semiconductors. Materials for SC-OFETs are first reviewed with descriptions of the fabrication methods and the field-effect characteristics. In particular, a benchmark carrier mobility of 20–40 cm2 Vs−1, achieved with thin platelets of rubrene single crystals, demonstrates the significance of the SC-OFETs and clarifies material limitations for organic devices. In the latter part of this review, we discuss the physics of microscopic charge transport by using SC-OFETs at metal/semiconductor contacts and along semiconductor/insulator interfaces. Most importantly, Hall effect and electron spin resonance (ESR measurements reveal that interface charge transport in molecular semiconductors is properly described in terms of band transport and localization by charge traps.

  1. TOPICAL REVIEW: Organic field-effect transistors using single crystals

    Science.gov (United States)

    Hasegawa, Tatsuo; Takeya, Jun

    2009-04-01

    Organic field-effect transistors using small-molecule organic single crystals are developed to investigate fundamental aspects of organic thin-film transistors that have been widely studied for possible future markets for 'plastic electronics'. In reviewing the physics and chemistry of single-crystal organic field-effect transistors (SC-OFETs), the nature of intrinsic charge dynamics is elucidated for the carriers induced at the single crystal surfaces of molecular semiconductors. Materials for SC-OFETs are first reviewed with descriptions of the fabrication methods and the field-effect characteristics. In particular, a benchmark carrier mobility of 20-40 cm2 Vs-1, achieved with thin platelets of rubrene single crystals, demonstrates the significance of the SC-OFETs and clarifies material limitations for organic devices. In the latter part of this review, we discuss the physics of microscopic charge transport by using SC-OFETs at metal/semiconductor contacts and along semiconductor/insulator interfaces. Most importantly, Hall effect and electron spin resonance (ESR) measurements reveal that interface charge transport in molecular semiconductors is properly described in terms of band transport and localization by charge traps.

  2. Preparation, structure and luminescence properties of nanocrystalline Eu:Gd{sub 3}Sc{sub 2}Ga{sub 3}O{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Shao Shufang [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China)], E-mail: shfshao@aiofm.ac.cn; Zhang Qingli [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Liu Wenpeng [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Sun Dunlu; Gu Changjiang; Yin Shaotang [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China)

    2009-03-05

    Eu:Gd{sub 3}Sc{sub 2}Ga{sub 3}O{sub 12} powder was synthesized by co-precipitation method with metal Ga, Eu{sub 2}O{sub 3}, Gd{sub 2}O{sub 3}, Sc{sub 2}O{sub 3} as starting materials and aqueous ammonia as precipitator. X-ray diffraction (XRD), the Rietveld refinement method and transmission electron microscope (TEM) were employed to study the crystal structure. The fluorescent spectra and decay curves were used to investigate the luminescence properties of the resulting powders. The XRD spectra and results of the Rietveld refinement indicated that the structure of Gd{sub 3}Sc{sub 2}Ga{sub 3}O{sub 12} hardly changed and only crystal lattice distorted a little when Eu{sup 3+} ion was doped. The transmission electron microscope (TEM) observation and XRD line broadening calculation revealed that the particle size of Eu:Gd{sub 3}Sc{sub 2}Ga{sub 3}O{sub 12} powder increased with the increase of the calcination temperature. At the same time, the emission intensity and lifetime of Eu:Gd{sub 3}Sc{sub 2}Ga{sub 3}O{sub 12} powder also increased with the calcination temperature. In the emission spectra, a 590 nm orange line from {sup 5}D{sub 0} {yields} {sup 7}F{sub 1} as the most prominent group meaned that Eu{sup 3+} ion mainly occupied the inversion center in Gd{sub 3}Sc{sub 2}Ga{sub 3}O{sub 12} crystal which may be caused by a small number of Gd atoms entered the 16(a) site.

  3. Synthesis, crystal structure, growth, optical and third order nonlinear optical studies of 8HQ2C5N single crystal - An efficient third-order nonlinear optical material

    Energy Technology Data Exchange (ETDEWEB)

    Divya Bharathi, M.; Ahila, G.; Mohana, J. [Department of Physics, Presidency College, Chennai 600005 (India); Chakkaravarthi, G. [Department of Physics, CPCL Polytechnic College, Chennai 600068 (India); Anbalagan, G., E-mail: anbu24663@yahoo.co.in [Department of Nuclear Physics, University of Madras, Chennai 600025 (India)

    2017-05-01

    A neoteric organic third order nonlinear optical material 8-hydroxyquinolinium 2-chloro-5-nitrobenzoate dihydrate (8HQ2C5N) was grown by slow cooling technique using ethanol: water (1:1) mixed solvent. The calculated low value of average etch pit solidity (4.12 × 10{sup 3} cm{sup −2}) indicated that the title crystal contain less defects. From the single crystal X-ray diffraction data, it was endowed that 8HQ2C5N crystal belongs to the monoclinic system with centrosymmetric space group P2{sub 1}/c and the cell parameters values, a = 9.6546 (4) Ǻ, b = 7.1637(3) Ǻ, c = 24.3606 (12) Ǻ, α = γ = 90°, β = 92.458(2)° and volume = 1683.29(13) Ǻ{sup 3}. The FT-IR and FT-Raman spectrum were used to affirm the functional group of the title compound. The chemical structure of 8HQ2C5N was scrutinized by {sup 13}C and {sup 1}H NMR spectral analysis and thermal stability through the differential scanning calorimetry study. Using optical studies the lower cut-off wavelength and optical band gap of 8HQ2C5N were found to be 364 nm and 3.17 eV respectively. Using the single oscillator model suggested by Wemple – Didomenico, the oscillator energy (E{sub o}), the dispersion energy (E{sub d}) and static dielectric constant (ε{sub o}) were estimated. The third-order susceptibility were determined as Im χ{sup (3)} = 2.51 × 10{sup −5} esu and Re χ{sup (3)} = 4.46 × 10{sup −7} esu. The theoretical third-order nonlinear optical susceptibility χ{sup (3)} was calculated and the results were compared with experimental value. Photoluminescence spectrum of 8HQ2C5N crystal showed the yellow emission. The crystal had the single shot laser damage threshold of 5.562 GW/cm{sup 2}. Microhardness measurement showed that 8HQ2C5N belongs to a soft material category. - Highlights: • A new organic single crystals were grown and the crystal structure was reported. • Crystal possess, good transmittance, thermal and mechanical stability. • Single shot LDT value is found to be

  4. The properties of optimal two-dimensional phononic crystals with different material contrasts

    Science.gov (United States)

    Liu, Zong-Fa; Wu, Bin; He, Cun-Fu

    2016-09-01

    By modifying the spatial distribution of constituent material phases, phononic crystals (PnCs) can be designed to exhibit band gaps within which sound and vibration cannot propagate. In this paper, the developed topology optimization method (TOM), based on genetic algorithms (GAs) and the finite element method (FEM), is proposed to design two-dimensional (2D) solid PnC structures composed of two contrasting elastic materials. The PnCs have the lowest order band gap that is the third band gap for the coupled mode, the first band gap for the shear mode or the XY 34 Z band gap for the mixed mode. Moreover, the effects of the ratios of contrasting material properties on the optimal layout of unit cells and the corresponding phononic band gaps (PBGs) are investigated. The results indicate that the topology of the optimal PnCs and corresponding band gaps varies with the change of material contrasts. The law can be used for the rapid design of desired PnC structures.

  5. MIS and MFIS Devices: DyScO3 as a gate-oxide and buffer-layer

    Science.gov (United States)

    Melgarejo, R.; Karan, N. K.; Saavedra-Arias, J.; Pradhan, D. K.; Thomas, R.; Katiyar, R. S.

    2008-03-01

    Metal-Ferroelectric-Insulator-Semiconductor (MFIS) structure is of importance in nonvolatile memories, as insulating buffer layer that prevents interdiffusion between the ferroelectric (FE) and the Si substrate. However, insulating layer has some disadvantages viz. generation of depolarization field in FE film and increase of operation voltage. To overcome this, it is important to find a FE with low ɛr (compared to normal FE) and an insulating buffer layer with high ɛr (compared to ɛr = 3.9 of SiO2). High-k materials viz. LaAlO3, SiN, HfO2, HfAlO etc. have been studied as buffer layers in the MFIS structures and as gate-oxide in metal-insulator-silicon (MIS). Recently, a novel gate dielectric material, DyScO3 was considered and studies indicate that crystallization temperature significantly increased and the film on Si remained amorphous even at 1000 C annealing. Considering the requirements on crystallization temperature, ɛr, electrical stability for high-k buffer layers, DyScO3 seems to be very promising for future MFIS device applications. Therefore, the evaluations of MOCVD grown DyScO3 as gate-oxide for MIS and the buffer layers for Bi3.25La0.75Ti3O12 based MFIS structures are presented.

  6. Thermoelastic properties of ScB2, TiB2, YB4 and HoB4: Experimental and theoretical studies

    DEFF Research Database (Denmark)

    Waśkowska, A.; Gerward, Leif; Staun Olsen, J.

    2011-01-01

    High-pressure X-ray diffraction in ScB2, TiB2, YB4 and HoB4 powders and single crystals has been studied using synchrotron radiation as well as conventional X-rays. The experimental results are supported by calculations using density functional theory. ScB2, YB4 and HoB4 are hard materials (bulk...... modulus 180–200 GPa), while TiB2 may be classified as superhard (bulk modulus about 260 GPa). We report here first experimental and theoretical determinations of the bulk modulus for HoB4 (195(5) and 198.2 GPa, respectively), and first experimental values of the bulk modulus for ScB2 (196(2) GPa) and YB4...

  7. Material characterization and finite element modelling of cyclic plasticity behavior for 304 stainless steel using a crystal plasticity model

    OpenAIRE

    Lu, Jiawa; Sun, Wei; Becker, Adib A.

    2016-01-01

    Low cycle fatigue tests were carried out for a 304 stainless steel at room temperature. A series of experimental characterisations, including SEM, TEM, and XRD were conducted for the 304 stainless steel to facilitate the understanding of the mechanical responses and microstructural behaviour of the material under cyclic loading including nanostructure, crystal structure and the fractured surface. The crystal plasticity finite element method (CPFEM) is a powerful tool for studying the microstr...

  8. Effects of Parameter Modulation on Near-Field Imaging in Photonic Crystal Consisting of Alternately Left-Handed Material and Right-Handed Material

    Institute of Scientific and Technical Information of China (English)

    WANG Qiong; YAN Chang-Chun; ZHANG Ling-Ling; CUI Yi-Ping

    2008-01-01

    @@ By means of the transfer-matrix method, the effects of parameter modulation on the quality of near-field imaging in one-dimensional photonic crystal consisting of alternately Lett-handed material and right-handed material are investigated.Based on analyses of the recovery rate and ph'ase shift, the results show that the imaging quality is not obviously affected by the minor changes of layer thickness.In addition, by modulating the material parameters of the Lett-handed material, it is found that for both the real part and the imaginary part, the system is more sensitive to the permeability than the permittivity for the TE wave.For the TM wave, it is reverse.These properties are very useful to fabricate Lett-handed material photonic crystals in practice.

  9. Final Report of “Collaborative research: Fundamental science of low temperature plasma-biological material interactions” (Award# DE-SC0005105)

    Energy Technology Data Exchange (ETDEWEB)

    Oehrlein, Gottlieb S. [Univ. of Maryland, College Park, MD (United States); Seog, Joonil [Univ. of Maryland, College Park, MD (United States); Graves, David [Univ. of California, Berkeley, CA (United States); Chu, J. -W. [Univ. of California, Berkeley, CA (United States)

    2014-09-24

    temperature plasma sources with modified geometry where radical induced interactions generally dominate due to short mean free paths of ions and VUV photons. In these conditions we demonstrated the importance of environmental interactions of plasma species when APP sources are used to modify biomolecules. This is evident from both gas phase characterization data and in-situ surface characterization of treated biomolecules. Environmental interactions can produce unexpected outcomes due to the complex reactions of reactive species with the atmosphere which determine the composition of reactive fluxes and atomistic changes in biomolecules. Overall, this work elucidated a richer spectrum of scientific opportunities and challenges for the field of low temperature plasma-biomolecule surface interactions than initially anticipated, in particular, for plasma sources operating at atmospheric pressure. The insights produced in this work, e.g. demonstration of the importance of environmental interactions, are generally important for applications of APP to materials modifications. Thus one major contributions of this research has been the establishment of methodologies to study the interaction of plasma with bio-molecules in a systemic and rigorous manner. In particular, our studies of atmospheric pressure plasma sources using very well-defined experimental conditions enabled us to correlate atomistic surface modifications of biomolecules with changes in their biological function. The clarification of the role of ions, VUV photons and radicals in deactivation of biomolecules during low pressure and atmospheric pressure plasma-biomolecule interaction has broad implications, e.g. for the emerging field of plasma medicine. The development of methods to detect the effects of plasma treatment on immune-active biomolecules will lay a fundamental foundation to enhance our understanding of the effect of plasma on biological systems. be helpful in many future studies.

  10. Analysis on characteristics of 1-D apodized and chirped photonic crystals containing negative refractive materials

    Institute of Scientific and Technical Information of China (English)

    TONG Kai; CUI Wei-wei; XU Xiao-hui; LI Zhi-quan

    2008-01-01

    Using transfer matrix method, the optical transmission properties of 1-D photonic crystals composed partially of negativerefraction media are analyzed. The transmission spectra of periodic photonic crystal, chirped photonic crystal and apodizedphotonic crystal are numerically simulated respectively. By contrast with optical transmission properties of ordinary photo-nic crystals made of positive refraction media, the transmission spectra of apodized photonic crystal become unregular, theBragg flat-headed area recurs but the peak of transmission does not change significantly. Futhermore, the band gap rangeof chirped photonic crystal diminishes gradually.

  11. Growth and characterization of benzaldehyde 4-nitro phenyl hydrazone (BPH) single crystal: A proficient second order nonlinear optical material

    Science.gov (United States)

    Saravanan, M.; Abraham Rajasekar, S.

    2016-04-01

    The crystals (benzaldehyde 4-nitro phenyl hydrazone (BPH)) appropriate for NLO appliance were grown by the slow cooling method. The solubility and metastable zone width measurement of BPH specimen was studied. The material crystallizes in the monoclinic crystal system with noncentrosymmetric space group of Cc. The optical precision in the whole visible region was found to be excellent for non-linear optical claim. Excellence of the grown crystal is ascertained by the HRXRD and etching studies. Laser Damage Threshold and Photoluminescence studies designate that the grown crystal contains less imperfection. The mechanical behaviour of BPH sample at different temperatures was investigated to determine the hardness stability of the grown specimen. The piezoelectric temperament and the relative Second Harmonic Generation (for diverse particle sizes) of the material were also studied. The dielectric studies were executed at varied temperatures and frequencies to investigate the electrical properties. Photoconductivity measurement enumerates consummate of inducing dipoles due to strong incident radiation and also divulge the nonlinear behaviour of the material. The third order nonlinear optical properties of BPH crystals were deliberate by Z-scan method.

  12. Growth and characterization studies of sodium Di(L-Malato) borate bulk single crystal: A promising nonlinear optical material

    Science.gov (United States)

    Senthil, A.; Loganayaki, M.; Lenin, M.; Ramasamy, P.

    2012-06-01

    A semi-organic nonlinear optical material, sodium di(L-malato) borate (NaDMB) has been synthesized. Optically good quality bulk single crystal of NaDMB was successfully grown by slow evaporation solution technique (SEST) and Sankaranarayanan-Ramasamy (SR) method at 36 °C. Transparent, colourless crystal of size 22 mm X 8 mm X 6 mm with well defined morphology was grown by SEST and oriented unidirectional bulk single crystal of size 48 mm length and 16 mm diameter was grown by SR method. The grown crystals were subjected to single crystal X-ray diffraction studies. The crystal belongs to monoclinic structure with space group P21. The grown crystals were characterized by UV-vis studies. The structural perfection of the grown crystal has been analyzed by high-resolution X-ray diffraction (HRXRD) rocking curve measurements. The differential thermal (DTA) and thermogravimetric (TG) analysis traces reveal the thermal stability of the sample. The second-harmonic generation efficiency was estimated by Kurtz and Perry powder technique.

  13. Ice crystallization in porous building materials: assessing damage using real-time 3D monitoring

    Science.gov (United States)

    Deprez, Maxim; De Kock, Tim; De Schutter, Geert; Cnudde, Veerle

    2017-04-01

    Frost action is one of the main causes of deterioration of porous building materials in regions at middle to high latitudes. Damage will occur when the internal stresses due to ice formation become larger than the strength of the material. Hence, the sensitivity of the material to frost damage is partly defined by the structure of the solid body. On the other hand, the size, shape and interconnection of pores manages the water distribution in the building material and, therefore, the characteristics of the pore space control potential to form ice crystals (Ruedrich et al., 2011). In order to assess the damage to building materials by ice crystallization, lot of effort was put into identifying the mechanisms behind the stress build up. First of all, volumetric expansion of 9% (Hirschwald, 1908) during the transition of water to ice should be mentioned. Under natural circumstances, however, water saturation degrees within natural rocks or concrete cannot reach a damaging value. Therefore, linear growth pressure (Scherer, 1999), as well as several mechanisms triggered by water redistribution during freezing (Powers and Helmuth, 1953; Everett, 1961) are more likely responsible for damage due to freezing. Nevertheless, these theories are based on indirect observations and models and, thus, direct evidence that reveals the exact damage mechanism under certain conditions is still lacking. To obtain this proof, in-situ information needs to be acquired while a freezing process is performed. X-ray computed tomography has proven to be of great value in material research. Recent advances at the Ghent University Centre for Tomography (UGCT) have already allowed to dynamically 3D image crack growth in natural rock during freeze-thaw cycles (De Kock et al., 2015). A great potential to evaluate the different stress build-up mechanisms can be found in this imaging technique consequently. It is required to cover a range of materials with different petrophysical properties to achieve

  14. Mechanical properties and material removal characteristics of soft-brittle HgCdTe single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Irwan, R. [School of Mechanical and Mining Engineering, the University of Queensland, Brisbane, QLD 4072 (Australia); Huang, H., E-mail: han.huang@uq.edu.au [School of Mechanical and Mining Engineering, the University of Queensland, Brisbane, QLD 4072 (Australia); Zheng, H.Y.; Wu, H. [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore)

    2013-01-01

    Mechanical properties and material removal characteristics of mercury cadmium telluride (Hg{sub 0.84}C{sub 0.16}Te) single crystals were investigated by the use of indentation and single point diamond turning. The nanoindentation tests showed that the average values of elastic modulus and hardness were 40 and 0.55 GPa, respectively. The fracture toughness estimated by Vickers indentation fracture toughness test was 0.200 MPa m{sup 1/2}, in the predicted range of 0.204-0.235 MPa m{sup 1/2} by the Bifano model. The diamond turning experiments revealed that there was a threshold value in depth of cut that was responsible for the transition from ductile to brittle removal modes during the cutting of the Hg{sub 0.84}C{sub 0.16}Te single crystals. The measured critical depth of cut was between 1.5 and 2 {mu}m, in agreement with that of 1.541 {mu}m calculated by the Bifano model.

  15. The Influence of Grain Size and Crystal Content on Rheology and Deformation of Pyroclastic Material

    Science.gov (United States)

    Paquereau-Lebti, P.; Robert, G.; Grunder, A. L.; Russell, K. J.

    2007-12-01

    Pyroclastic deposits undergo variable degrees of sintering, viscous deformation of particles and loss of pore space, which combine to produce the dramatic textural variations that define welded facies. We here investigate the effects of grain size and crystal content on the rheology and welding of pyroclastic material.Uniaxial deformation experiments were conducted using sintered cores of natural rhyolite ash under conditions consistent with welding. Experiments were done in the University of British Columbia Volcanology Deformation Rig (VDR). This apparatus is designed to run experiments relevant to volcanology, by supporting low-load, high temperature, deformation experiments (Quane et al., 2004). We ran experiments at constant displacement rate (2.5.10-6 m.s-1), under ambient water pressure ("Dry"), at temperatures of 850 and 900°C and to maximal strain of 50%. Grain-size effect was investigated using sintered cores from three different sieving fractions of Rattlesnake Tuff (RST, Eastern Oregon, USA) ash: fine ash (grain size 15% crystal content inhibited sintering in a sample that welded under the same experimental conditions when phenocryst depleted (phenocryst content around 1% in whole Rattlesnake Tuff ash). Reference: Quane, S.L., Russell, J.K., and Kennedy, L.A. (2004). A low-load, high-temperature deformation apparatus for volcanological studies. American mineralogist, 89, 873-877.

  16. Piezoelectric and Dielectric Properties of Fe2O3-Doped 0.57Pb(Sc1/2Nb1/2)O3 0.43PbTiO3 Ceramic Materials

    Science.gov (United States)

    Kim, Jin-Soo; Kim, So-Jung; Kim, Ho-Gi; Lee, Duck-Chool; Uchino, Kenji

    1999-03-01

    High-power piezoelectric materials are presently being extensively developed for applications such as ultrasonic motors and piezoelectric transformers. In this study, the piezoelectric and dielectric properties of Fe2O3-doped 0.57Pb(Sc1/2Nb1/2)O3 0.43PbTiO3 (hereafter 0.57PSN 0.43PT), which is the morphotropic phase boundary composition of the PSN PT system, were investigated. The maximum dielectric constant (ɛ33/ɛ0=2551) and the minimum dielectric loss (tanδ=0.51%) at room temperature were obtained at Fe2O3 additions of 0.1 wt% and 0.3 wt%, respectively. The temperature dependence of the dielectric constant and the dielectric loss was measured between room temperature and 350°C. With the addition of Fe2O3, the piezoelectric constant d33 and electromechanical coupling factor kp were slightly decreased, but the mechanical quality factor Qm was significantly increased. The highest mechanical quality factor (Qm=297) was obtained at 0.3 wt% Fe2O3, which is 4.4 times higher than that of nondoped 0.57PSN 0.43PT ceramics. The P E and S E loops of the samples at room temperature and at 1.0 Hz were measured at the same time using an automated polarization measuring system.

  17. Coordinate-Invariant Lyddane-Sachs-Teller Relationship for Polar Vibrations in Materials with Monoclinic and Triclinic Crystal Systems.

    Science.gov (United States)

    Schubert, Mathias

    2016-11-18

    A coordinate-invariant generalization of the Lyddane-Sachs-Teller relation is presented for polar vibrations in materials with monoclinic and triclinic crystal systems. The generalization is derived from an eigendielectric displacement vector summation approach, which is equivalent to the microscopic Born-Huang description of polar lattice vibrations in the harmonic approximation. An expression for a general oscillator strength is also described for materials with monoclinic and triclinic crystal systems. A generalized factorized form of the dielectric response characteristic for monoclinic and triclinic materials is proposed. The generalized Lyddane-Sachs-Teller relation is found valid for monoclinic β-Ga_{2}O_{3}, where accurate experimental data became available recently from a comprehensive generalized ellipsometry investigation [Phys. Rev. B 93, 125209 (2016)]. Data for triclinic crystal systems can be measured by generalized ellipsometry as well, and are anticipated to become available soon and results can be compared with the generalized relations presented here.

  18. Modeling the material properties at the onset of damage initiation in bulk potassium dihydrogen phosphate crystals

    Science.gov (United States)

    Demos, Stavros G.; Feit, Michael D.; Duchateau, Guillaume

    2014-10-01

    A model simulating transient optical properties during laser damage in the bulk of KDP/DKDP crystals is presented. The model was developed and tested using as a benchmark its ability to reproduce the well-documented damage initiation behaviors but most importantly, the salient behavior of the wavelength dependence of the damage threshold. The model involves two phases. During phase I, the model assumes a moderate localized initial absorption that is strongly enhanced during the laser pulse via excited state absorption and thermally driven generation of additional point defects in the surrounding material. The model suggests that during a fraction of the pulse duration, the host material around the defect cluster is transformed into a strong absorber that leads to significant increase of the local temperature. During phase II, the model suggests that the excitation pathway consists mainly of one photon absorption events within a quasicontinuum of short-lived vibronic defect states spanning the band gap that was generated after the initial localized heating of the material due to thermal quenching of the excited state lifetimes. The width of the transition (steps) between different number of photons is governed by the instantaneous temperature, which was estimated using the experimental data. The model also suggests that the critical physical parameter prior to initiation of breakdown is the conduction band electron density. This model, employing very few free parameters, for the first time is able to quantitatively reproduce the wavelength dependence of the damage initiation threshold, and thus provides important insight into the physical processes involved.

  19. III-V compound SC for optoelectronic devices

    Directory of Open Access Journals (Sweden)

    Sudha Mokkapati

    2009-04-01

    Full Text Available III-V compound semiconductors (SC have played a crucial role in the development of optoelectronic devices for a broad range of applications. Major applications of InP or GaAs based III-V compound SC are devices for optical fiber communications, infrared and visible LEDs/LDs and high efficiency solar cells. GaN based compounds are extremely important for short wavelength light emitters used in solid state lighting systems. We review the important device applications of various III-V compound SC materials.

  20. Reactions of {[Pd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd](&mgr;-SC(6)F(5))}(4).2O(C(2)H(5))(2). Crystal Structures of the Complexes [(Ph(3)P)Pd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd(SC(6)F(5))].1.4CH(2)Cl(2) and [(Ph(3)P)Pd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd(PPh(3))]SO(3)CF(3).2CH(2)Cl(2) and ab Initio MO Calculations on the Model Systems [(H(3)P)Pd(&mgr;-H(2)PCH(2)PH(2))(&mgr;-SH)Pd(PH(3))](+) and [(H(3)P)Pd(&mgr;-H(2)PCH(2)PH(2))Pd(PH(3))](2+).

    Science.gov (United States)

    Usón, Rafael; Forniés, Juan; Fernández Sanz, Javier; Usón, Miguel A.; Usón, Isabel; Herrero, Santiago

    1997-04-23

    {[Pd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd](&mgr;-SC(6)F(5))}(4) reacts 1:4 with neutral ligands L to give [LPd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd(SC(6)F(5))] or 1:8 to form [LPd(&mgr;-SC(6)F(5))(&mgr;-dppm)PdL](+) (dppm = bis(diphenylphosphino)methane). These binuclear complexes retain the palladium-palladium bond and the two dissimilar bridging ligands, as demonstrated by the X-ray structural determinations carried out on [(Ph(3)P)Pd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd(SC(6)F(5))].1.4CH(2)Cl(2) and [(Ph(3)P)Pd(&mgr;-SC(6)F(5))(&mgr;-dppm)Pd(PPh(3))]SO(3)CF(3).2CH(2)Cl(2). Ab initio calculations on the model systems [(H(3)P)Pd(&mgr;-H(2)PCH(2)PH(2))(&mgr;-SH)Pd(PH(3))](+) and [(H(3)P)Pd(&mgr;-H(2)PCH(2)PH(2))Pd(PH(3))](2+) show that the metal-metal bond arises mainly from interactions between palladium sp orbitals, which also play a predominant role in the binding with the sulfur bridge.

  1. Collective spin waves in reconfigurable artificial crystals and magnonic meta-materials

    Science.gov (United States)

    Grundler, Dirk

    2014-03-01

    Periodically nanopatterned ferromagnets have generated great interest in the research field of magnonics in that they support spin-wave (SW) nanochannels, allow for multi-directional emission of short-wavelength SWs via the grating coupler effect and form artificial crystals for SWs (magnons) in the GHz frequency regime. Allowed SW minibands and forbidden frequency gaps are not just tailored by the geometrical and material parameters, but reflect decisively the periodic order of the nanomagnets' remanent magnetization. Thereby a further degree of freedom is offered for controlling wave phenomena in solids compared to photonics and plasmonics. We investigated such so-called reconfigurable magnonic crystals (MCs) consisting of a one-dimensional (1D) array of permalloy nanostripes that allow one to vary the Brillouin zone boundaries, forbidden frequency gaps and number of SW minibands in one-and-the same device. When excited by a microwave antenna, an unexpected metamaterial property was found in that both reciprocal and nonreciprocal SW excitation occurred depending on the parallel and antiparallel alignment of magnetic moments in neighboring stripes. Such excitation characteristics are not found in natural materials. Switching an individual stripe from parallel to antiparallel magnetization in an otherwise saturated 1D MC modified the transmitted SW amplitude considerably offering SW control on the nanoscale. Combined with the grating coupler effect, periodically nanopatterned ferromagnets are expected to provide interesting building blocks for magnonic applications aiming at transmitting and processing information at microwave frequencies with spin waves. Funding from the European Community's 7th Framework Programme (FP7/2007-2013) under grant No. 228673 MAGNONICS, No. 247556 NoWaPhen, the DFG via GR1640/5-1 (SPP 1538) and the German Excellence Cluster `Nanosystems Initiative Munich (NIM)' is acknowledged.

  2. Cyclotron production of (44)Sc: From bench to bedside.

    Science.gov (United States)

    van der Meulen, Nicholas P; Bunka, Maruta; Domnanich, Katharina A; Müller, Cristina; Haller, Stephanie; Vermeulen, Christiaan; Türler, Andreas; Schibli, Roger

    2015-09-01

    (44)Sc, a PET radionuclide, has promising decay characteristics (T1/2 = 3.97 h, Eβ(+)av = 632 keV) for nuclear imaging and is an attractive alternative to the short-lived (68)Ga (T1/2 = 68 min, Eβ(+)av = 830 keV). The aim of this study was the optimization of the (44)Sc production process at an accelerator, allowing its use for preclinical and clinical PET imaging. (44)CaCO3 targets were prepared and irradiated with protons (~11 MeV) at a beam current of 50 μA for 90 min. (44)Sc was separated from its target material using DGA extraction resin and concentrated using SCX cation exchange resin. Radiolabeling experiments at activities up to 500 MBq and stability tests were performed with DOTANOC by investigating different scavengers, including gentisic acid. Dynamic PET of an AR42J tumor-bearing mouse was performed after injection of (44)Sc-DOTANOC. The optimized chemical separation method yielded up to 2 GBq (44)Sc of high radionuclidic purity. In the presence of gentisic acid, radiolabeling of (44)Sc with DOTANOC was achieved with a radiochemical yield of ~99% at high specific activity (10 MBq/nmol) and quantities which would allow clinical application. The dynamic PET images visualized increasing uptake of (44)Sc-DOTANOC into AR42J tumors and excretion of radioactivity through the kidneys of the investigated mouse. The concept "from-bench-to-bedside" was clearly demonstrated in this extended study using cyclotron-produced (44)Sc. Sufficiently high activities of (44)Sc of excellent radionuclidic purity are obtainable for clinical application, by irradiation of enriched calcium at a cyclotron. This work demonstrates a promising basis for introducing (44)Sc to clinical routine of nuclear imaging using PET. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Spectroscopic characterization of Yb:Sc2O3 transparent ceramics

    Institute of Scientific and Technical Information of China (English)

    Lu Shen-Zhou; Yang Qiu-Hong

    2012-01-01

    Yb:Sc2O3 transparent ceramics are fabricated by a conventional ceramic process and sintering in H2 atmosphere.The room-temperature spectroscopic properties are investigated,and the Raman spectrum shows an obvious vibration characteristic band centred at 415 cm-1. There are three broad absorption bands around 891,937,and 971 nm,respectively.The strongest emission peak is centred at 1.04 μm with a broad bandwidth (11 nm) and an emission cross-section of 1.8× 10-20 cm2.The gain coefficient implies a possible laser ability in a range from 990 nm to 1425 nm.The energy-level structure shows that Yb:Sc2O3 ceramics have large Stark splitting at the ground state level due to their strong crystal field.All the results show that Yb:Sc2Oa transparent ceramics are a promising material for short pulse lasers.

  4. Crystal surface integrity and diffusion measurements on Earth and planetary materials

    Science.gov (United States)

    Watson, E. B.; Cherniak, D. J.; Thomas, J. B.; Hanchar, J. M.; Wirth, R.

    2016-09-01

    Characterization of diffusion behavior in minerals is key to providing quantitative constraints on the ages and thermal histories of Earth and planetary materials. Laboratory experiments are a vital source of the needed diffusion measurements, but these can pose challenges because the length scales of diffusion achievable in a laboratory time are commonly less than 1 μm. An effective strategy for dealing with this challenge is to conduct experiments involving inward diffusion of the element of interest from a surface source, followed by quantification of the resulting diffusive-uptake profile using a high-resolution depth-profiling technique such as Rutherford backscattering spectroscopy (RBS), nuclear reaction analysis (NRA), or ion microprobe (SIMS). The value of data from such experiments is crucially dependent on the assumption that diffusion in the near-surface of the sample is representative of diffusion in the bulk material. Historical arguments suggest that the very process of preparing a polished surface for diffusion studies introduces defects-in the form of dislocations and cracks-in the outermost micrometer of the sample that make this region fundamentally different from the bulk crystal in terms of its diffusion properties. Extensive indirect evidence suggests that, in fact, the near-surface region of carefully prepared samples is no different from the bulk crystal in terms of its diffusion properties. A direct confirmation of this conclusion is nevertheless clearly important. Here we use transmission electron microscopy to confirm that the near-surface regions of olivine, quartz and feldspar crystals prepared using careful polishing protocols contain no features that could plausibly affect diffusion. This finding does not preclude damage to the mineral structure from other techniques used in diffusion studies (e.g., ion implantation), but even in this case the role of possible structural damage can be objectively assessed and controlled. While all

  5. Study on the crystallization process of function inorganic crystal materials%无机功能晶体材料的结晶过程研究

    Institute of Scientific and Technical Information of China (English)

    孙丛婷; 薛冬峰

    2014-01-01

    Functional crystal materials used as the important conversion media of light,sound and electricity,have been widely applied to high-tech fields such as energy,information,aerospace and related hot topics at the forefront of materials science and engineering subject.Crystallization process is the core of the preparation of functional materials,crystal growth habit of materials directly affects the functional performances of optical,electrical,magnetic,and catalytic behaviors.During the crystallization process of inorganic materials,crystals are microscopically transformed from free-state ions into the crystalline solid-phase.We can use the ionic electronegativity and microscopic symmetry changes of constituent components,to study the crystallization process of aggregation formation and structure evolution.Using molecular vibration spectroscopy we can at the molecular scale,reveal the crystallization process of nonlinear optical crystal materials in aqueous solution crystallization process,to overcome the lack of traditional means of in situ observations determining those non-long-range order structures.Chemical bonding theory of single crystal growth can from both thermodynamic and kinetic aspects of the whole system,effectively guide the growth of large crystals,reasonably regulate the growth surface and interface thermodynamics and kinetics.The chemical bonding theory of single crystal growth is applied to the design and optimization of growth parameters of large-size crystal pulling growth system,we have built up a large-size crystal growth system,and successfully grown φ2" sapphire crystals,φ3" YAG crystals,and φ4" lithium niobate crystals.%功能晶体材料作为光、声、电等转换的重要介质,已经被广泛应用于能源、信息、航空航天等高新技术领域,是目前国际材料科学与工程学科发展的热点和前沿课题.结晶过程是制备功能材料的核心环节,结晶习性直接影响材料的光、电、磁、催化等

  6. Monitor of SC beam profiles

    CERN Multimedia

    1977-01-01

    A high-resolution secondary emission grid for the measurement of SC beam profiles. Modern techniques of metal-ceramic bonding, developed for micro-electronics, have been used in its construction. (See Annual Report 1977 p. 105 Fig. 12.)

  7. First coil for the SC

    CERN Multimedia

    CERN PhotoLab

    1955-01-01

    The coils for the SC magnet were stored in the large hangar of the Cointrin Airport (to make sure that they would be available before snow and ice would block the roads and canals from Belgium, where they were built).

  8. Preparation and crystal structures of some binary pnictides of scandium, zirconium, and hafnium: Sc{sub 5}Bi{sub 3}, ZrBi, {alpha}-HfSb, HfBi, HfBi{sub 2}, and the compound Zr{sub 5}Bi{sub 3}X{sub 1-x}, possibly stabilized by an impurity (X)

    Energy Technology Data Exchange (ETDEWEB)

    Haase, M.G.; Block, H.; Jeitschko, W. [Muenster Univ. (Germany). Anorganisch-Chemisches Inst.

    2001-08-01

    The title compounds were prepared by reaction of the elemental components. Of these Sc{sub 5}Bi{sub 3} is a new compound. Its orthorhombic {beta}-Yb{sub 5}Sb{sub 3} type crystal structure was determined from single-crystal X-ray data: Pnma, a = 1124.4(1) pm, b = 888.6(1) pm, c = 777.2(1) pm, R = 0.024 for 1140 structure factors and 44 variable parameters. For the other compounds we have established the crystal structures. ZrBi has ZrSb type structure with a noticeable homogeneity range. This structure type was also found for the low temperature ({alpha}) form of HfSb and for HfBi. For {alpha}-HfSb this structure was refined from single-crystal X-ray data: Cmcm, a = 377.07(4) pm, b = 1034.7(1) pm, c = 1388.7(1) pm, R = 0.043 for 432 F values and 22 variables. HfBi{sub 2} has TiAs{sub 2} type structure: Pnnm, a = 1014.2(2) pm, b = 1563.9(3) pm, c = 396.7(1) pm. The structure was refined from single-crystal data to a residual of R = 0.074 for 1038 F values and 40 variables. In addition, a zirconium bismuthide, possibly stabilized by light impurity elements X and crystallizing with the hexagonal Mo{sub 5}Si{sub 3}C{sub 1-x} type structure, was observed: Zr{sub 5}Bi{sub 3}X{sub 1-x}, a = 873.51(6) pm, c = 599.08(5) pm. The positions of the heavy atoms of this structure were refined from X-ray powder film data. Various aspects of impurity stabilization of intermetallics are discussed. (orig.)

  9. Growth and characterization of Bis(L-threonine) copper (II) monohydrate single crystals: A semiorganic second order nonlinear optical material

    Science.gov (United States)

    Subhashini, R.; Sathya, D.; Sivashankar, V.; Latha Mageshwari, P. S.; Arjunan, S.

    2016-12-01

    Highly transparent solitary nonlinear semiorganic optical material Bis(L-threonine) copper (II) monohydrate [BLTCM], was synthesized by a conventional slow evaporation solution growth technique. The grown crystals were subjected to structural, optical, electrical, thermal, mechanical, SHG and Laser damage threshold studies. Single crystal XRD shows that the material crystallizes in monoclinic system with noncentrosymmetric space group P21. FT-IR and FT-RAMAN analyses confirm the various functional groups present in the grown crystal. The transparency range of BLTCM was determined by UV-vis-NIR studies and various optical constants such as extinction coefficient (K), refractive index, optical conductivity and electric susceptibility with real and imaginary parts of dielectric constant were calculated using the transmittance data which have applications in optoelectronic devices. Dielectric studies of the crystal were carried out at different frequencies and temperatures to analyze the electrical properties. TGA and DSC analyses were performed to study the thermal behaviour of the sample. The hardness stability of the grown specimen was investigated by Vickers microhardness test. The output intensity of second harmonic generation was confirmed using the Kurtz and Perry powder method. The laser induced surface damage threshold of the crystal was measured using Nd:YAG laser.

  10. Materials Chemistry Issues in the Development of a Single-Crystal Solar/Thermal Refractive Secondary Concentrator

    Science.gov (United States)

    Jacobson, Nathan S.; Biering, Robert C.

    2005-01-01

    A translucent crystal concentrates and transmits energy to a heat exchanger, which in turn heats a propellant gas, working gas of a dynamic power system, or a thermopile. Materials are the limiting issue in such a system. Central is the durability of the crystal, which must maintain the required chemical, physical/optical, and mechanical properties as it is heated and cooled. This report summarizes available data to date on the materials issues with this system. We focus on the current leading candidate materials, which are sapphire (Al2O3) for higher temperatures and silica (SiO2) for lower temperatures. We use data from thermochemical calculations; laboratory coupon tests with silica and sapphire; and system tests with sapphire. The required chemical properties include low-vapor pressure and interfacial stability with supporting structural materials. Optical properties such as transmittance and index of refraction must be maintained. Thermomechanical stability is a major challenge for a large, single-crystal ceramic and has been discussed in another report. In addition to the crystal, other materials in the proposed system include refractory metals (Nb, Ta, Mo, W, and Re), carbon (C), and high-temperature ceramic insulation. The major issue here is low levels of oxygen, which lead to volatile refractory metal oxides and rapid consumption of the refractory metal. Interfacial reactions between the ceramic crystal and refractory metal are also discussed. Finally, high-temperature ceramic insulating materials are also likely to be used in this system. Outgassing is a major issue for these materials. The products of outgassing are typically reactive with the refractory metals and must be minimized.

  11. Effect of the glass wool material on the two-dimensional steel-air phononic crystal

    Science.gov (United States)

    Yu, Kunpeng; Chen, Tianning; Wang, Xiaopeng; Li, Yinggang

    2013-12-01

    Using the finite-element method, the propagation behaviors of acoustic waves in a new two-dimensional phononic crystal (PC) composed of slotted steel tube periodically placed in air matrix are investigated. Unlike traditional PCs, the tube inclusions here are not hollow but filled with the glass wool (GW) material. By calculating dispersion relations and transmission spectra of the PC, the effect of GW on PCs is studied. Numerical results show that the presence of GW can shift the first band gap to lower frequencies while it has little effect on the second band gap; meanwhile it can also enhance the sound attenuation of PCs in the pass band frequencies, resulting in the decrease of noise in the whole frequency range. The analysis of acoustic eigenmodes shows that GW affects the band and transmission performances mainly through changing the resonance of the internal cavity inside the tube and meanwhile the sound-absorbing ability of GW itself. Furthermore, some parameters of GW are studied for their effects on the sound-propagation properties of PCs. Results show that the transmission behaviors can be significantly modulated by parameters such as the surface exposure degree, mean fiber diameter and the material's apparent density of GW.

  12. Liquid crystal chiroptical polarization rotators for the near-UV region: theory, materials, and device applications

    Science.gov (United States)

    Saulnier, D.; Taylor, B.; Marshall, K. L.; Kessler, T. J.; Jacobs, S. D.

    2013-09-01

    The helical structure of a chiral-nematic liquid crystal (CLC) material produces a number of interesting optical properties, including selective reflection and optical rotatory power. To take advantage of the high optical rotation near the selective reflection peak for applications in the UV, either large concentrations of chiral components or those possessing very large helical twisting powers (HTP's) are necessary. It is difficult to find chiral twisting agents with high HTP that do not degrade the UV transmission. We report what we believe to be the first experimental observation of extraordinarily high optical rotation (LC) layer thickness. Using this model, the optical rotation at λ = 355 nm for the 1% CB 15/ZLI-1646 mixture is determined computationally, with the results in agreement with experimental data obtained by evaluating a series of wedged cells using an areal mapping, Hinds Exicor 450XT Mueller Matrix Polarimeter. This finding now opens a path to novel LC optics for numerous near-UV applications. One such envisioned application for this class of materials would be UV distributed polarization rotators (UV-DPR's) for largeaperture, high-peak-power lasers.

  13. Performance of PIN-PMN-PT Single Crystal Piezoelectric versus PZT8 Piezoceramic Materials in Ultrasonic Transducers

    Science.gov (United States)

    DeAngelis, D. A.; Schulze, G. W.

    The recent advancements in the manufacturing of single crystal PIN-PMN-PT piezoelectric materials now make them a cost-competitive alternative to PZT4 and PZT8 (Navy Types I and III) piezoceramic materials, which have been the workhorse of power ultrasonic applications (e.g., welding, cutting, sonar, etc.) for over 50 years. Although there are great benefits to the use of single crystal materials with respect to high output, as well as added actuating and sensing abilities, many transducer designers are still reluctant to explore these materials due to inadequate design guidelines for substituting the familiar PZT materials; for example, what are the implications of the higher capacitance, sensitivity to chipping/cracks, aging effects, frequency shifts, or how much preload can be used are all common questions. This research is a case study on the performance of identical ultrasonic transducer bodies, used for semiconductor wire bonding, assembled with either PZT8 or PIN-PMN-PT piezo material. The main purpose of the study is to establish rule-of-thumb design guidelines for direct substitution of single crystal materials in existing PZT8 transducer designs, along with a side-by-side performance comparison to highlight benefits. Several metrics are investigated such as impedance, frequency, displacement gain, quality factor and electromechanical coupling factor.

  14. LOCAL COLLISION SIMULATION OF AN SC WALL USING ENERGY ABSORBING STEEL

    Directory of Open Access Journals (Sweden)

    CHUL-HUN CHUNG

    2013-08-01

    Full Text Available This study evaluates the local damage of a turbine in an auxiliary building of a nuclear power plant due to an external impact by using the LS-DYNA finite element program. The wall of the auxiliary building is SC structure and the material of the SC wall plate is high manganese steel, which has superior ductility and energy absorbance compared to the ordinary steel used for other SC wall plates. The effects of the material of the wall, collision speed, and angle on the magnitude of the local damage were evaluated by local collision analysis. The analysis revealed that the SC wall made of manganese steel had significantly less damage than the SC wall made of ordinary steel. In conclusion, an SC wall made of manganese steel can have higher effective resistance than an SC wall made of ordinary steel against the local collision of an airplane engine or against a turbine impact.

  15. Survival of Organic Materials in Ancient Cryovolcanically-Produced Halite Crystals

    Science.gov (United States)

    Zolensky, M.; Fries, M.; Chan, Q. H.-S.; Kebukawa, Y.; Bodnar, R.; Burton, A.; Callahan, M.; Steele, A.; Sandford, S.

    2015-01-01

    Spectroscopic evidence supports the presence of Mg-Na-K salts derived from cryovolcanism on the surface of Europa. Halite (NaCl) is effective at very long-term preservation of organic phases and structures. Collection of salt crystals from Europan plumes would provide solid inclusions of organics, potentially also biomaterials, all suitable for analysis. Two thermally-metamorphosed ordinary chondrite regolith breccias (Monahans 1998 (H5) and Zag (H3-6)) contain fluid and solid inclusion-bearing halite crystals, dated to approximately 4.5 billion years, and thus the trapped aqueous fluids and solids are at least as old. Heating/freezing studies of the aqueous fluid inclusions in these halites demonstrated that they were trapped near 25 degrees Centigrade, and their continued presence in the halite grains requires that their incorporation into the H chondrite asteroid occurred after that body's metamorphism ended, since heating would have dessicated the halite. O and H isotopes of the trapped fluids are consistent with mixing of asteroidal and cometary water. Cryovolcanic Origin of the Halite: We hypothesize that these meteoritic halites derive from ancient cryovolcanism based on the following points. (1) Salts crystals are observed as products of current cryovolcanism on Enceladus. (2) In-situ spacecraft analysis of some of the icy grains associated with the Enceladus salt found minor organic or siliceous components, including methane, also found in the Monahans halite. (3) Cryovolcanic fluids are observed to be in chemical disequilibrium, reflecting incomplete reactions between interior volatiles and rocky materials. The coexistence of N2 and HCN in Enceladus' cryovolcanic fluids requires that the plume consists of a mixture of materials whose sources experienced different degrees of aqueous processing, including primordial material trapped in ice that has not been in contact with liquid water. The observed mineral assemblage within the Monahans and Zag halites is

  16. Passively Q-switched ytterbium-doped ScBO3 laser with black phosphorus saturable absorber

    Science.gov (United States)

    Lu, Dazhi; Pan, Zhongben; Zhang, Rui; Xu, Tianxiang; Yang, Ruilong; Yang, Bingchao; Liu, Zhongyuan; Yu, Haohai; Zhang, Huaijin; Wang, Jiyang

    2016-08-01

    We demonstrate a passively Q-switched Yb3+-doped ScBO3 bulk laser using a black phosphorous (BP) saturable absorber, a two-dimensional semiconductor. The response spectra of BP show that it is suitable as a universal switcher in the spectral range from the visible to midinfrared band. Considering the saturable absorption properties of BP and emission properties of Yb3+-doped crystals, the passively Q-switched bulk laser pulses were realized with the Yb3+:ScBO3 crystal as a gain material and a fabricated BP sample as a Q-switcher. Because of the large energy storage capacity of Yb3+:ScBO3, the maximum output energy is obtained to be 1.4 μJ, which is comparable with the previous reported maximum energy of graphene Q-switched lasers. The obtained results identify the potential capability of BP as a pulse modulator in bulk lasers, and BP plays an increasingly important role in a wide range of its applications, including photonics and optoelectronics.

  17. Crystal growth and electronic properties of a 3D Rashba material, BiTeI, with adjusted carrier concentrations.

    Science.gov (United States)

    Kanou, Manabu; Sasagawa, Takao

    2013-04-03

    3D Rashba materials can be a leading player in spin-related novel phenomena, ranging from the metallic extreme (unconventional superconductivity) to the transport intermediate (spin Hall effects) to the novel insulating variant (3D topological insulating states). As the essential backbone for both fundamental and applied research of such a 3D Rashba material, this study established the growth of sizeable single crystals of a candidate compound BiTeI with adjusted carrier concentrations. Three techniques (standard vertical Bridgman, modified horizontal Bridgman, and vapour transport) were employed, and BiTeI crystals (>1 × 1 × 0.2 mm(3)) with fundamentally different electronic states from metallic to insulating were successfully grown by the chosen technique. The 3D Rashba electronic states, including the Fermi surface topology, for the corresponding carrier concentrations of the obtained BiTeI crystals were revealed by relativistic first-principles calculations.

  18. Acid-base chemistry in the formation of Mackay-type icosahedral clusters: μ3-acidity analysis of Sc-rich phases of the Sc-Ir system.

    Science.gov (United States)

    Guo, Yiming; Stacey, Timothy E; Fredrickson, Daniel C

    2014-05-19

    The crystal structures of intermetallic phases offer a wealth of geometrical features (helices, multishelled clusters, and host-guest motifs) whose formation has yet to be explained or predicted by chemical theory. A recently developed extension of the acid-base concept to metallic systems, the μ3-acidity model, provides an avenue for developing this understanding for intermetallics formed from transition metals. In this Article, we illustrate how this approach can be used to understand one of the most striking geometrical entities to emerge in intermetallic chemistry, the Mackay cluster of icosahedral quasicrystals. We present μ3-acidity analyses, based on DFT-calibrated Hückel calculations, for a series of Sc-Ir intermetallics: ScIr (CsCl-type), Sc2Ir (Ti2Ni-type), Sc11Ir4, and the Mackay cluster containing phases Sc57Ir13 and Sc44Ir7. We begin by illustrating that a μ3-acidity model correctly predicts that each of these phases is stable relative to disproportionation into their neighboring compounds when a common set of Hückel parameters and d-orbital occupancies is used. Next, we explain these results by developing a relationship between the distance distribution of homoatomic contacts within an atom's coordination sphere and the μ3-neutralization it experiences. For a given average homoatomic distance, the role of heteroatomic contacts is higher when the distribution of homoatomic contacts is narrower. This effect is key to the strength of the acid-base neutralization of the Sc-rich phases, where the Sc atoms find a scarcity of Ir atoms from which to obtain neutralization. Under these circumstances, Sc-Ir contacts should be maximized, whereas the number and distance variations of the Sc-Sc contacts should be minimized. These expectations are borne out by the observed crystal structures. In particular, the Mackay clusters of Sc57Ir13 and Sc44Ir7, in which a central Ir atom is icosahedrally coordinated by a pentagonal dodecahedral array of face-sharing Sc

  19. A review on solar cells from Si-single crystals to porous materials and quantum dots.

    Science.gov (United States)

    Badawy, Waheed A

    2015-03-01

    Solar energy conversion to electricity through photovoltaics or to useful fuel through photoelectrochemical cells was still a main task for research groups and developments sectors. In this article we are reviewing the development of the different generations of solar cells. The fabrication of solar cells has passed through a large number of improvement steps considering the technological and economic aspects. The first generation solar cells were based on Si wafers, mainly single crystals. Permanent researches on cost reduction and improved solar cell efficiency have led to the marketing of solar modules having 12-16% solar conversion efficiency. Application of polycrystalline Si and other forms of Si have reduced the cost but on the expense of the solar conversion efficiency. The second generation solar cells were based on thin film technology. Thin films of amorphous Si, CIS (copper-indium-selenide) and t-Si were employed. Solar conversion efficiencies of about 12% have been achieved with a remarkable cost reduction. The third generation solar cells are based on nano-crystals and nano-porous materials. An advanced photovoltaic cell, originally developed for satellites with solar conversion efficiency of 37.3%, based on concentration of the solar spectrum up to 400 suns was developed. It is based on extremely thin concentration cells. New sensitizer or semiconductor systems are necessary to broaden the photo-response in solar spectrum. Hybrids of solar and conventional devices may provide an interim benefit in seeking economically valuable devices. New quantum dot solar cells based on CdSe-TiO2 architecture have been developed.

  20. A review on solar cells from Si-single crystals to porous materials and quantum dots

    Directory of Open Access Journals (Sweden)

    Waheed A. Badawy

    2015-03-01

    Full Text Available Solar energy conversion to electricity through photovoltaics or to useful fuel through photoelectrochemical cells was still a main task for research groups and developments sectors. In this article we are reviewing the development of the different generations of solar cells. The fabrication of solar cells has passed through a large number of improvement steps considering the technological and economic aspects. The first generation solar cells were based on Si wafers, mainly single crystals. Permanent researches on cost reduction and improved solar cell efficiency have led to the marketing of solar modules having 12–16% solar conversion efficiency. Application of polycrystalline Si and other forms of Si have reduced the cost but on the expense of the solar conversion efficiency. The second generation solar cells were based on thin film technology. Thin films of amorphous Si, CIS (copper–indium–selenide and t-Si were employed. Solar conversion efficiencies of about 12% have been achieved with a remarkable cost reduction. The third generation solar cells are based on nano-crystals and nano-porous materials. An advanced photovoltaic cell, originally developed for satellites with solar conversion efficiency of 37.3%, based on concentration of the solar spectrum up to 400 suns was developed. It is based on extremely thin concentration cells. New sensitizer or semiconductor systems are necessary to broaden the photo-response in solar spectrum. Hybrids of solar and conventional devices may provide an interim benefit in seeking economically valuable devices. New quantum dot solar cells based on CdSe–TiO2 architecture have been developed.

  1. Assembly of a supercrystal (SC) of the CMS endcap electromagnetic calorimeter

    CERN Multimedia

    J. Williams et al., RAL

    2004-01-01

    The first three pictures show the insertion of the first three rows of crystals into the supercrystal SC03 on Jan. 2004 and the completion of the SC endstops. Fig. 4 shows a complete supercrystal and Fig. 5 its components (alveolar, interface plate, housing, optical fibre, insert, crystal and VPT, endstop). A set of 25 inserts is shown in Fig. 6, while Fig. 7 shows housing, interface plates and inserts. Finally, a SC rear view showing the Vacum Phototriode (VPT) wires through the inserts can be seen in Fig. 8. Fig. 9 and 10 show two supercrystals under test on Dee F and R, respectively.

  2. Method for the preparation of inorganic single crystal and polycrystalline electronic materials

    Science.gov (United States)

    Groves, W. O. (Inventor)

    1969-01-01

    Large area, semiconductor crystals selected from group 3-5 compounds and alloys are provided for semiconductor device fabrication by the use of a selective etching operation which completely removes the substrate on which the desired crystal was deposited. The substrate, selected from the same group as the single crystal, has a higher solution rate than the epitaxial single crystal which is essentially unaffected by the etching solution. The preparation of gallium phosphide single crystals using a gallium arsenide substrate and a concentrated nitric acid etching solution is described.

  3. Crystallization and solid-state reaction as a route to asymmetric synthesis from achiral starting materials.

    Science.gov (United States)

    Green, B S; Lahav, M

    1975-10-29

    Many molecules which are achiral can crystallize in chiral (enantiomorphic) crystals and, under suitable conditions, crystals of only one chirality may be obtained. The formation of right- or left-handed crystals in excess is equally probable. Lattice-controlled (topochemical) photochemical or thermal solid-state reactions may then afford stable, optically active products. In the presence of the chiral products, achiral reactants may preferentially produce crystals of one chirality, leading to a feedback mechanism for the generation and amplification of optical activity. Amplification of optical activity can also be achieved by solid-state reactions. The optical synthesis of biologically relevant compounds by such routes may be envisaged.

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

    NARCIS (Netherlands)

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

    2007-01-01

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

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

    NARCIS (Netherlands)

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

    2007-01-01

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

  6. Optically and electrically controlled circularly polarized emission from cholesteric liquid crystal materials doped with semiconductor quantum dots.

    Science.gov (United States)

    Bobrovsky, Alexey; Mochalov, Konstantin; Oleinikov, Vladimir; Sukhanova, Alyona; Prudnikau, Anatol; Artemyev, Mikhail; Shibaev, Valery; Nabiev, Igor

    2012-12-04

    Novel types of electro- and photoactive quantum dot-doped cholesteric materials have been engineered. UV-irradiation or electric field application allows one to control the degree of circular polarization and intensity of fluorescence emission by prepared quantum dot-doped liquid crystal films. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Large single crystal growth of MnWO4-type materials from high-temperature solutions

    Science.gov (United States)

    Gattermann, U.; Röska, B.; Paulmann, C.; Park, S.-H.

    2016-11-01

    A simple high-temperature growth apparatus was constructed to obtain large crystals of chemically gradient (In, Na)-doped MnWO4solid-solutions. This paper presents the crystal growth and characterisation of both MnWO4and epitaxially grown (In, Na): MnWO4crystals on MnWO4. These large monolithic crystals were made in two steps: A MnWO4 crystal was grown in the crystallographic main direction [001] applying the Czochralski method, followed by the top seeded growth of (In, Na): MnWO4 solid-solutions with an oriented seed crystal of MnWO4. Such a monolithic crystal will serve to fundamental investigation of coupling properties at boundaries between various multiferroic MnWO4-typesolid-solutions.

  8. IEC SC15E: Report on liaison activities of CIGRÉ-SC15

    DEFF Research Database (Denmark)

    Henriksen, Mogens

    2000-01-01

    WG’s activities under CIGRÉ SC15:WG 15.01 - Fluid impregnated systems.WG 15.02 - Dielectric Liquids.WG 15.03 - Gas Insulation.WG 15.04 - Outdoor Insulation.WG 15.05 - Capacitors.WG 15.07 - Solid Insulating Materials for Rotating Machines.WG 15/33.08 - Insulation Monitoring and Life Estimation. WG...

  9. Polymerization shrinkage of flowable resin-based restorative materials

    OpenAIRE

    Stavridakis, Minos M; Dietschi, Didier; Krejci, Ivo

    2005-01-01

    This study measured the linear polymerization displacement and polymerization forces induced by polymerization shrinkage of a series of flowable resin-based restorative materials. The materials tested were 22 flowable resin-based restorative materials (Admira Flow, Aelite Flow, Aeliteflow LV, Aria, Crystal Essence, Definite Flow, Dyract Flow, Filtek Flow, FloRestore, Flow-it, Flow-Line, Freedom, Glacier, OmegaFlo, PermaFlo, Photo SC, Revolution 2, Star Flow, Synergy Flow, Tetric Flow, Ultrase...

  10. Exploration of photonic crystal circulator based on gyromagnetic properties and scaling of ferrite materials

    Science.gov (United States)

    Umamaheswari, C.; sundar, D. Shanmuga; Raja, A. Sivanantha

    2017-01-01

    Three port optical circulators are designed predicated on two dimensional triangular lattice photonic crystals and examined with different size of regular (circular) and irregular (triangular) ferrite posts, through the structure optimization and exploration of defect mode coupling. Ferrite, a special type of highly permeable and low-loss magnetic material, which is anisotropic when biased by a much larger static magnetic field is modeled and the gyromagnetic property of the same is investigated. According to theoretical analysis, the optimized geometry structure can make the non-reciprocal transmission of electromagnetic waves accompanying a high caliber isolation and low insertion loss with the avail of ferrite post inserted at the center of the joint. In order to minimize the reflections in the isolated port at the nominal frequencies, the scaling of ferrite post is implemented by defining S parameter. The structural optimization and the calculation of tensor elements of the anisotropic medium is executed by the finite element method. Moreover, the further study shows the importance of scaling the magneto-photonic material and the way it affects the transmission and isolation of the structured contrivance. Numerical simulations are performed to manifest the attainability and the characteristics of the designed circulators. Finally the triangular ferrite post with the scale of 0.518 makes the non-reciprocal transmission of electromagnetic waves with the minimum insertion loss at the normalized frequency range of 191.6 GHz which benefits from a broad operational bandwidth. This optimized device can realize the operations of splitting, routing and isolation and have good technological compatibility for chip level integration into Photonic Integrated Circuits.

  11. Photonic gaps in one dimensional cylindrical photonic crystal that incorporates single negative materials

    Science.gov (United States)

    El-Naggar, Sahar A.

    2017-01-01

    In this article, we theoretically study electromagnetic waves that propagate in one-dimensional cylindrical photonic crystals (1DCPC) containing single negative materials. We examine the optical properties of three gaps namely; the zero-effective phase (zero- ϕ), the zero-permittivity (zero- ɛ) and the zero-permeability (zero- μ). We calculate the optical reflectance for transverse electric(magnetic) TE(TM) polarizations using the transfer matrix method in the cylindrical coordinates. We study the effect of azimuthal mode number ( m) and the starting radius on these gaps. The results show that the zero- μ (zero- ɛ) gap is found for TE(TM) polarization at frequency where μ( ɛ) changes its sign for m ≥ 1. The width of the gap increases by decreasing the starting radius or by increasing m, whereas the zero- ϕ gap remains invariant. In addition, we present a brief design of 1D-CPC that has a polarization-independent wide gap especially for high azimuthal mode number ( m > 2). Our results can help improve the performance of microwave devices independent of the source wave polarization.

  12. Organic crystals – More than simple additives toward better electroceramic materials

    Directory of Open Access Journals (Sweden)

    Mamoru Senna

    2010-09-01

    Full Text Available Roles of various organic crystals (OC, notably those containing nitrogen, on the preparation and properties of source materials for electroceramics are featured from the author’s own experimental studies. When OC are intimately mixed with metal salts like carbonates, their decomposition is accelerated, liberating the diffusing species at temperatures lower than usual. Mixing of OC with metal oxides under mechanical stressing results in anion exchange and eases diffusion of guest species. Case studies on 3 categories, i.e. i substitution of oxygen in titania with nitrogen and introduction of oxygen vacancies during co-grinding titania with urea, glycine and/or polytetra fluoroethylene; ii increase in the rate of reaction of barium titanate formation via a solid state route by OCs with detailed process analysis with glycine as an example of OC, and iii phase pure solid state synthesis of Li4Ti5O12 by mechanically activating the intermediate, Li2TiO3 with 3 amino acids as OCs.

  13. Stochastic polarity formation in molecular crystals, composite materials and natural tissues

    Directory of Open Access Journals (Sweden)

    Jürg Hulliger

    2017-07-01

    Full Text Available This topical review summarizes the theoretical and experimental findings obtained over the last 20 years on the subject of growth-induced polarity formation driven by a Markov chain process. When entering the growing surface of a molecular crystal, an inorganic–organic composite or a natural tissue, the building blocks may undergo 180° orientational disorder. Driven by configurational entropy, faulted orientations can promote the conversion of a growing non-polar seed into an object showing polar domains. Similarly, orientational disorder at the interface may change a polar seed into a two-domain state. Analytical theory and Monte Carlo simulations were used to model polarity formation. Scanning pyroelectric, piezoresponse force and phase-sensitive second-harmonic microscopies are methods for investigating the spatial distribution of polarity. Summarizing results from different types of materials, a general principle is provided for obtaining growth-induced polar domains: a non-zero difference in the probabilities for 180° orientational misalignments of building blocks, together with uni-directional growth, along with Markov chain theory, can produce objects showing polar domains.

  14. A 4-D dataset for validation of crystal growth in a complex three-phase material, ice cream

    Science.gov (United States)

    Rockett, P.; Karagadde, S.; Guo, E.; Bent, J.; Hazekamp, J.; Kingsley, M.; Vila-Comamala, J.; Lee, P. D.

    2015-06-01

    Four dimensional (4D, or 3D plus time) X-ray tomographic imaging of phase changes in materials is quickly becoming an accepted tool for quantifying the development of microstructures to both inform and validate models. However, most of the systems studied have been relatively simple binary compositions with only two phases. In this study we present a quantitative dataset of the phase evolution in a complex three-phase material, ice cream. The microstructure of ice cream is an important parameter in terms of sensorial perception, and therefore quantification and modelling of the evolution of the microstructure with time and temperature is key to understanding its fabrication and storage. The microstructure consists of three phases, air cells, ice crystals, and unfrozen matrix. We perform in situ synchrotron X-ray imaging of ice cream samples using in-line phase contrast tomography, housed within a purpose built cold-stage (-40 to +20oC) with finely controlled variation in specimen temperature. The size and distribution of ice crystals and air cells during programmed temperature cycling are determined using 3D quantification. The microstructural evolution of three-phase materials has many other important applications ranging from biological to structural and functional material, hence this dataset can act as a validation case for numerical investigations on faceted and non-faceted crystal growth in a range of materials.

  15. SHG Materials Based on the AlPO4-5 Single Crystals

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Large AlPO4-5 molecular sieve single crystals with high optical quality were synthesized hydrothermally by using TPA as template. As-synthesized crystals were calcined under O2 atmosphere to remove the organic templates in the channels. Disperse-Red-1 (DR1) and p-nitroaniline (pNA) molecules have been successfully incorporated into the one-dimensional channels of AlPO4-5 single crystals respectively by means of vapor phase diffusion. XRD patterns reveal that the loading of organic molecules has not destroyed the structures of AlPO4-5 crystals. Polarizing microscope and SHG results indicate that the DR1 and pNA molecules are well aligned in a preferred direction along the crystal channels. The different polarization-dependence SH intensity shows that different SHG processes occur in the DR1- and pNA-loaded AlPO4-5 crystals.

  16. History of the "Detector Materials Engineering" Crystal Growth Process for Bulk Hg1- x Cd x Te

    Science.gov (United States)

    Higgins, W. M.; Nelson, D. A.; Roy, R. G.; Murosako, R. P.; Lancaster, R. A.; Tower, J.; Norton, P.

    2013-11-01

    This paper reviews the history and technology of a bulk Hg1- x Cd x Te crystal growth process that was developed in the early 1980s at Honeywell Electro-Optics Division (presently BAE Systems, Electronic Solutions). The crystal growth process name, DME, was an acronym for the department name: Detector Materials Engineering. This was an accelerated crucible rotation technique (ACRT) vertical traveling heater method growth process. Crystal growth occurred in the pseudobinary Hg1- x Cd x Te system. ACRT mixing allowed the lower-density, higher- x-value Hg1- x Cd x Te growth nutrient in the upper region of the ampoule to replenish the depleted melt and allowed the growth of constant- x-value, higher-density Hg1- x Cd x Te. The material grown by this research and production growth process yielded single crystals that had improved purity, compositional uniformity, precipitate density, and reproducibility in comparison with solid-state recrystallization and other bulk Hg1- x Cd x Te growth techniques. Radial and longitudinal nonuniformities in x-value for Hg1- x Cd x Te were reduced to DME material had highly desired performance characteristics.

  17. Experimental Conditions to Obtain Photopolymerization Induced Phase Separation Process in Liquid Crystal-Photopolymer Composite Materials under Laser Exposure

    Directory of Open Access Journals (Sweden)

    Manuel Ortuño

    2014-01-01

    Full Text Available We analyze the experimental conditions necessary to obtain a photopolymerization induced phase separation process inside liquid crystal-photopolymer composite materials. Composites stored for 24 hours perform poorly in hologram recording but a good result is obtained if they are used recently prepared. We use a procedure combining heat and sonication to disarrange the liquid crystal structures formed during storage of the composite. We also propose incoherent light treatment after recording the hologram in order to evaluate if the phase separation evolved correctly during hologram recording.

  18. Research on the Crystal Growth and Dielectric Properties of High Permittivity Ferroelectric Materials.

    Science.gov (United States)

    1983-03-01

    Paraclastic 8a 2 . 14L0 .71 222 NOW 42m 4/amm Nb2.5762.501 Three Antiferroelectric *Ferroelectric *Paraelectric *Paraelectric eroel astic Ferroel astic Paraci ...astic Paraci astic 8 01 Rockwell International Science Center SC5345.3AR (BaSr)5Nbj0O30 as Ba2 _xSrxK.yNayNb505 , yields more stuffed and stable

  19. Thermal oxidation of single crystal aluminum antimonide and materials having the same

    Science.gov (United States)

    Sherohman, John William; Yee, Jick Hong; Coombs, III, Arthur William; Wu, Kuang Jen J.

    2012-12-25

    In one embodiment, a method for forming a non-conductive crystalline oxide layer on an AlSb crystal includes heat treating an AlSb crystal in a partial vacuum atmosphere at a temperature conducive for air adsorbed molecules to desorb, surface molecule groups to decompose, and elemental Sb to evaporate from a surface of the AlSb crystal and exposing the AlSb crystal to an atmosphere comprising oxygen to form a crystalline oxide layer on the surface of the AlSb crystal. In another embodiment, a method for forming a non-conductive crystalline oxide layer on an AlSb crystal includes heat treating an AlSb crystal in a non-oxidizing atmosphere at a temperature conducive for decomposition of an amorphous oxidized surface layer and evaporation of elemental Sb from the AlSb crystal surface and forming stable oxides of Al and Sb from residual surface oxygen to form a crystalline oxide layer on the surface of the AlSb crystal.

  20. Crystallization and C-RAM application of Ag-doped Sb{sub 2}Te{sub 3} material

    Energy Technology Data Exchange (ETDEWEB)

    Xu Jiaqing [Research Center of Functional Semiconductor Film Engineering and Technology, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, CAS, 865 Changning Road, Shanghai 200050 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100080 (China)]. E-mail: xjq@mail.sim.ac.cn; Liu Bo [Research Center of Functional Semiconductor Film Engineering and Technology, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, CAS, 865 Changning Road, Shanghai 200050 (China); Song Zhitang [Research Center of Functional Semiconductor Film Engineering and Technology, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, CAS, 865 Changning Road, Shanghai 200050 (China); Feng Songlin [Research Center of Functional Semiconductor Film Engineering and Technology, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, CAS, 865 Changning Road, Shanghai 200050 (China); Chen Bomy [Silicon Storage Technology Inc., 1171 Sonora Court, Sunnyvale, CA 94086 (United States)

    2006-02-25

    Ag-doped amorphous Sb{sub 2}Te{sub 3} thin films are deposited by RF magnetron sputtering and the crystallization behavior is studied by differential scanning calorimeter (DSC), X-ray diffraction and sheet resistance measurements. Both crystallization temperature and polycrystalline state resistance of Sb{sub 2}Te{sub 3} are increased by doping Ag, which is beneficial for enhancing room temperature stability of the polycrystalline state and reducing writing current in chalcogenide random access memory (C-RAM) application, respectively. The crystallization process of Sb{sub 2}Te{sub 3} is broadened with new phases (AgSbTe{sub 2} and Ag{sub 2}Te) formed. And a model is introduced to explain the peak positions in the DSC profiles. Applying the new material in the C-RAM test cell, current-voltage characteristic is studied to confirm its feasibility in device application.

  1. Synthesis of rod-like bis-ester liquid crystals and their influence on photoelectric properties of liquid crystalline materials

    Institute of Scientific and Technical Information of China (English)

    Min Yan Zheng; Yong Sheng Wei; Zhong Wei An; Shan Wang

    2009-01-01

    Six novel rod-like magnetic liquid crystals have been prepared,in which trans-bicyclobexyl or trans-cyclobexylphenyl and biphenylcarboxylic acid phenyl ester mesogenic cores with n-propyl and n-pentyl substituents were terminated by 4-hydroxylTEMPO (TEMPO = 2,2,6,6-tetramethylpiperidine-l-oxy).Their structures were confirmed by elemental analysis,IR and MS.Determined by SQUID,EPR,DSC and HS-POM (heat stage polarizing optical microscope),the six compounds all have both magnetic and liquid crystalline properties; their temperature ranges of mesophase were from 16.0 to 24.8 ~C,and the magnetic liquid crystal molecules could obviously improve the response sensitivity of liquid crystal materials.

  2. The Surface of Hybrid Perovskite Crystals: A Boon or Bane

    KAUST Repository

    Banavoth, Murali

    2017-03-03

    Hybrid perovskite single crystals have garnered tremendous research attention and are expected to be next-generation materials for high-efficiency photoactive devices. Therefore, it is fundamentally important to understand the 8 relationship between the optoelectronic properties of these materials and the marginally exploited surface chemistry in ambient air. For instance, a strong surface disorder, including hydration and ion migration, can possibly lead to extremely different optical and electronic properties at the surface compared to the bulk of the single crystal (SC). From this perspective, we evaluate the key variables that underlie the perovskite SC surface restructuring in ambient air and discuss their merits and limitations. In addition, a comprehensive picture of surface disordering, the remarkable change in the charge carrier dynamics and carrier mobility, surface hydration, and the effect of ion migration on the surface behavior will be discussed. Finally, surface passivation methods are highlighted to resolve or overcome the challenges for device integration.

  3. Final Technical Report for Award SC0008613

    Energy Technology Data Exchange (ETDEWEB)

    Knopf, Daniel A. [Stony Brook Univ., NY (United States)

    2017-04-05

    Discovering how aerosol particles, present in the atmosphere in sizes of a few nanometers to hundred micrometers, initiate ice crystal formation represents a great challenge. Atmospheric ice nucleation is important because ice crystals alter the radiative properties of clouds and thus climate, and impact precipitation and thus the hydrological cycle. The difficulty in predicting atmospheric ice formation is attributable at least in part, to the diversity of ice nucleation pathways, the physical and chemical complexity of the ice nucleating particles (INPs), and the relatively small numbers of INPs (compared with all other aerosol particles), sometimes less than one in 100000. These factors in turn makes constraining ice nucleation parameterizations for modeling applications challenging. The majority of airborne particles are known to be organic in nature or contain organic biogenic material. The presence of organic material adds to the complexity of the particles and therefore the predictability of ice nucleation events since the organic species can display different phase states, e.g. liquid or solid, in response to temperature and humidity. The award DE-SC0008613 to PI Prof. Daniel Knopf at Stony Brook University, “Relating the Chemical and Physical Properties of Aerosols to the Water Uptake and Ice Nucleation Potential of Particles Collected During the Carbonaceous Aerosols and Radiative Effects Study (CARES)”, allowed examination of laboratory generated aerosol particles and field-collected particles for their propensity to nucleate ice under typical tropospheric conditions and relate ice nucleation to the physicochemical properties of the particles including their morphology and chemical composition. This in turn allowed for development of ice nucleation parameterizations for implementation in cloud models. The award resulted in 10 peer-reviewed publications and more than 20 seminar and conference presentations. We demonstrated that the rate of immersion

  4. Rotary condenser for SC2

    CERN Multimedia

    1975-01-01

    During 1975 the SC2 performance was improved among other things by redesigning some of the elements of the ROTCO (Annual Report 1975, p. 55). The photo shows an interior wiew of the housing of the rotary condenser and of the sixteen sets of shaped stator blades.

  5. Visible luminescence of lanthanide ions in Ca3Sc2Si3O12 and Ca3Y2Si3O12

    Institute of Scientific and Technical Information of China (English)

    Fabio Piccinelli; Adolfo Speghini; Gino Mariotto; Laura Bovo; Marco Bettinelli

    2009-01-01

    The crystalline materials Ca3Sc2Si3O12 and Ca3Y2Si3O12 were characterized by different crystal structures,as the former is a cubic garnet,while the latter is an orthorhombic compound.We investigated the optical spectroscopy of these materials doped with several trivalent lanthanide ions and compared the results for the two hosts.Polycrystalline samples were prepared by solid state reaction,both undoped and doped with the trivalent lanthanide ions Eu3+,Tb3+ and Sm3+.Emission,excitation and Raman spectra of these materials were measured at temperatures ranging from 300 to 10 K.The optical spectra were assigned and discussed,and the effects of the crystal structure of the host on the spectroscopic behaviour were addressed.The technological potential of these compounds in the field of optical materials and devices was discussed.

  6. Influence of electron beam exposure on crystallization of phase-change materials

    NARCIS (Netherlands)

    Pandian, Ramanathaswamy; Kooi, Bart J.; De Hosson, Jeff Th. M.; Pauza, Andrew

    2007-01-01

    Isothermal crystallization of amorphous SbxTe films capped with ZnS-SiO2 or GeCrN layers was performed using in situ heating within a transmission electron microscope. The effect of the electron beam of the microscope on the crystallization process was investigated. It was found that electron irradi

  7. Single crystals of fullerene (C60 makes organic thick film solar cells and self supporting organic solar cells possible.

    Directory of Open Access Journals (Sweden)

    M. Umeno

    2008-06-01

    Full Text Available Single crystals of Fullerene (SC-C60 were synthesized by simple liquid/liquid interface precipitation method. Organic thick film solar cell (with an active layer thickness of approximately 20 microns thick is demonstrated by combining SC-C60 with poly(3-octylthiophene. Our preliminary results indicate that organic thick film solar cells are possible; which were considered to be impossible due to low mobility and small exciton diffusion lengths in most of the organic materials including small organic molecules and conjugated conducting polymers. Further, SC-C60 seems to be promising materials for organic photovoltaics. Self supporting organic solar cell is also demonstrated using SC-C60.

  8. Synthesis and Isolation of the Titanium-Scandium Endohedral Fullerenes-Sc2 TiC@Ih -C80 , Sc2 TiC@D5h -C80 and Sc2 TiC2 @Ih -C80 : Metal Size Tuning of the Ti(IV) /Ti(III) Redox Potentials.

    Science.gov (United States)

    Junghans, Katrin; Ghiassi, Kamran B; Samoylova, Nataliya A; Deng, Qingming; Rosenkranz, Marco; Olmstead, Marilyn M; Balch, Alan L; Popov, Alexey A

    2016-09-05

    The formation of endohedral metallofullerenes (EMFs) in an electric arc is reported for the mixed-metal Sc-Ti system utilizing methane as a reactive gas. Comparison of these results with those from the Sc/CH4 and Ti/CH4 systems as well as syntheses without methane revealed a strong mutual influence of all key components on the product distribution. Whereas a methane atmosphere alone suppresses the formation of empty cage fullerenes, the Ti/CH4 system forms mainly empty cage fullerenes. In contrast, the main fullerene products in the Sc/CH4 system are Sc4 C2 @C80 (the most abundant EMF from this synthesis), Sc3 C2 @C80 , isomers of Sc2 C2 @C82 , and the family Sc2 C2 n (2 n=74, 76, 82, 86, 90, etc.), as well as Sc3 CH@C80 . The Sc-Ti/CH4 system produces the mixed-metal Sc2 TiC@C2 n (2 n=68, 78, 80) and Sc2 TiC2 @C2 n (2 n=80) clusterfullerene families. The molecular structures of the new, transition-metal-containing endohedral fullerenes, Sc2 TiC@Ih -C80 , Sc2 TiC@D5h -C80 , and Sc2 TiC2 @Ih -C80 , were characterized by NMR spectroscopy. The structure of Sc2 TiC@Ih -C80 was also determined by single-crystal X-ray diffraction, which demonstrated the presence of a short Ti=C double bond. Both Sc2 TiC- and Sc2 TiC2 -containing clusterfullerenes have Ti-localized LUMOs. Encapsulation of the redox-active Ti ion inside the fullerene cage enables analysis of the cluster-cage strain in the endohedral fullerenes through electrochemical measurements.

  9. Studies on growth and characterization of a novel nonlinear optical and ferroelectric material - N,N-dimethylurea picrate single crystal

    Science.gov (United States)

    Shanthi, A.; Krishnan, C.; Selvarajan, P.

    2014-05-01

    A novel organic nonlinear optical (NLO) material viz. N,N-dimethylurea picrate (NNDMP) was grown by the slow evaporation technique using N,N-dimethyl formamide as a solvent. The solubility of the grown sample has been estimated for various temperatures. The XRD study reveals that the grown crystal crystallizes in the monoclinic crystal system and the corresponding lattice parameters were determined. The relative second harmonic generation (SHG) efficiency of the NNDMP was found to be 1.045 times that of KDP by Kurtz-Perry powder technique. FTIR and FT-Raman spectral analyses explain the various functional groups present in the sample. The optical spectral analysis of the grown crystal has been performed by UV-vis-NIR spectroscopy and the band gap energy was found out. The thermogravimetric analysis and differential thermal analysis (TG/DTA) reveal that the NNDMP crystal is stable at up to 172 °C. A prominent first-order ferroelectric to paraelectric phase transition at 323 K has been observed and activation energy was determined for the AC conduction process in the sample.

  10. Thermoelectric material including a multiple transition metal-doped type I clathrate crystal structure

    Science.gov (United States)

    Yang, Jihui; Shi, Xun; Bai, Shengqiang; Zhang, Wenqing; Chen, Lidong; Yang, Jiong

    2012-01-17

    A thermoelectric material includes a multiple transition metal-doped type I clathrate crystal structure having the formula A.sub.8TM.sub.y.sub.1.sup.1TM.sub.y.sub.2.sup.2 . . . TM.sub.y.sub.n.sup.nM.sub.zX.sub.46-y.sub.1.sub.-y.sub.2.sub.- . . . -y.sub.n.sub.-z. In the formula, A is selected from the group consisting of barium, strontium, and europium; X is selected from the group consisting of silicon, germanium, and tin; M is selected from the group consisting of aluminum, gallium, and indium; TM.sup.1, TM.sup.2, and TM.sup.n are independently selected from the group consisting of 3d, 4d, and 5d transition metals; and y.sub.1, y.sub.2, y.sub.n and Z are actual compositions of TM.sup.1, TM.sup.2, TM.sup.n, and M, respectively. The actual compositions are based upon nominal compositions derived from the following equation: z=8q.sub.A-|.DELTA.q.sub.1|y.sub.1-|.DELTA.q.sub.2|y.sub.2- . . . -|.DELTA.q.sub.n|y.sub.n, wherein q.sub.A is a charge state of A, and wherein .DELTA.q.sub.1, .DELTA.q.sub.2, .DELTA.q.sub.n are, respectively, the nominal charge state of the first, second, and n-th TM.

  11. Thermal and Transmission Properties of UV Nonlinear Optical Material-- ZnCd(SCN)4 Crystal

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Zinc cadmium thiocyanate(ZCTC), ZnCd(SCN)4, has been discovered as a UV second-order nonlinear optical coordination crystal. Its thermal and transmission properties are reported. The thermal decomposition is characterized by using the X-ray powder diffraction (XRPD) and infrared (IR) spectroscopy at room temperature. The absorptions of intrinsic ions and ZCTC in a solution state are discussed as well as transmission properties of the ZCTC crystal. An effective method of reducing the surface reflection loss of ZCTC crystal is introduced.

  12. Compensation of native donor doping in ScN: Carrier concentration control and p-type ScN

    Science.gov (United States)

    Saha, Bivas; Garbrecht, Magnus; Perez-Taborda, Jaime A.; Fawey, Mohammed H.; Koh, Yee Rui; Shakouri, Ali; Martin-Gonzalez, Marisol; Hultman, Lars; Sands, Timothy D.

    2017-06-01

    Scandium nitride (ScN) is an emerging indirect bandgap rocksalt semiconductor that has attracted significant attention in recent years for its potential applications in thermoelectric energy conversion devices, as a semiconducting component in epitaxial metal/semiconductor superlattices and as a substrate material for high quality GaN growth. Due to the presence of oxygen impurities and native defects such as nitrogen vacancies, sputter-deposited ScN thin-films are highly degenerate n-type semiconductors with carrier concentrations in the (1-6) × 1020 cm-3 range. In this letter, we show that magnesium nitride (MgxNy) acts as an efficient hole dopant in ScN and reduces the n-type carrier concentration, turning ScN into a p-type semiconductor at high doping levels. Employing a combination of high-resolution X-ray diffraction, transmission electron microscopy, and room temperature optical and temperature dependent electrical measurements, we demonstrate that p-type Sc1-xMgxN thin-film alloys (a) are substitutional solid solutions without MgxNy precipitation, phase segregation, or secondary phase formation within the studied compositional region, (b) exhibit a maximum hole-concentration of 2.2 × 1020 cm-3 and a hole mobility of 21 cm2/Vs, (c) do not show any defect states inside the direct gap of ScN, thus retaining their basic electronic structure, and (d) exhibit alloy scattering dominating hole conduction at high temperatures. These results demonstrate MgxNy doped p-type ScN and compare well with our previous reports on p-type ScN with manganese nitride (MnxNy) doping.

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

    OpenAIRE

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

    2007-01-01

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

  14. Magnetorheological finishing with chemically modified fluids for studying material removal of single-crystal ZnS

    Science.gov (United States)

    Salzman, S.; Romanofsky, H. J.; Clara, Y. I.; Giannechini, L. J.; West, Garrett J.; Lambropoulos, J. C.; Jacobs, S. D.

    2013-09-01

    Magnetorheological finishing (MRF) of polycrystalline, chemical-vapor-deposited (CVD) zinc sulfide (ZnS) and zinc selenide (ZnSe) can leave millimeter-size artifacts on the part surface. These pebble-like features come from the anisotropic mechanical and chemical properties of the ceramic material and from the CVD growth process itself. The resulting surface texture limits the use of MRF for polishing aspheric and other complex shapes using these important infrared (IR) ceramics. An investigation of the individual contributions of chemistry and mechanics to polishing of other polycrystalline ceramics has been employed in the past to overcome similar material anisotropy problems. The approach taken was to study the removal process for the different single-crystal orientations that comprise the ceramic, making adjustments to mechanics (polishing abrasive type and concentration) and polishing slurry chemistry (primarily pH) to equalize the removal rate for all crystal orientations. Polishing with the modified slurry was shown to prevent the development of surface texture. Here we present mechanical (microhardness testing) and chemical (acid etching) studies performed on the four single-crystal orientations of ZnS: 100, 110, 111, and 311. We found that the (111) plane is 35% to 55% harder and 30% to 40% more resistant to chemical etching than the other three planes. This relatively high degree of variation in these properties can help to explain the surface texture developed from MRF of the polycrystalline material. Theoretical calculations of microhardness, planar, and bond densities are presented and compared with the experimental data. Here surface characterization of these single-crystal orientations of ZnS for material removal and roughness with chemically modified MR fluids at various pH levels between pH 4 and pH 6 are presented for the first time.

  15. Cellulose nanocrystal-based materials : from liquid crystal self-assembly and glass formation to multifunctional thin films

    OpenAIRE

    Jan P. F. Lagerwall; Schütz, Christina; Salajkova, Michaela; Noh, Junghyun; PARK, JI HYUN; Scalia, Giusy; Bergström, Lennart

    2014-01-01

    Cellulose nanocrystals (CNCs), produced by the acid hydrolysis of wood, cotton or other cellulose-rich sources, constitute a renewable nanosized raw material with a broad range of envisaged uses: for example, in composites, cosmetics and medical devices. The intriguing ability of CNCs to self-organize into a chiral nematic (cholesteric) liquid crystal phase with a helical arrangement has attracted significant interest, resulting in much research effort, as this arrangement gives dried CNC fil...

  16. Atomic bonding and mechanical properties of Al-Mg-Zr-Sc alloy

    Institute of Scientific and Technical Information of China (English)

    高英俊; 班冬梅; 韩永剑; 钟夏平; 刘慧

    2004-01-01

    The valence electron structures of Al-Mg alloy with minor Sc and Zr were calculated according to the empirical electron theory(EET) in solid. The results show that because of the strong interaction of Al atom with Zr and Sc atom in melting during solidification, the Al3 Sc and Al3 (Sc1-xZrx) particles which act as heterogeneous nuclear are firstly crystallized in alloy to make grains refine. In progress of solidification, the Al-Sc, Al-Zr-Sc segregation regions are formed in solid solution matrix of Al-Mg alloy owing to the strong interaction of Al atom with Zr, Scatoms in bulk of alloy, so in the following homogenization treatment, the finer dispersed Al3 Sc and Al3 (Sc1-x Zrx) second-particles which are coherence with the matrix are precipitated in the segregation region. These finer second particles with the strong Al-Zr, Al-Sc covalent bonds can strengthen the covalent bonds in matrix of the alloy, and also enhance the hardness and strength of Al-Mg alloy. Those finer second-particles precipitated in interface of sub-grains can also strengthen the covalence bonds there, and effectively hinder the interface of sub-grains from migrating and restrain the sub-grains from growing, and cause better thermal stability of Al-Mg alloy.

  17. Crystal Structure Prediction and its Application in Earth and Materials Sciences

    Science.gov (United States)

    Zhu, Qiang

    First of all, we describe how to predict crystal structure by evolutionary approach, and extend this method to study the packing of organic molecules, by our specially designed constrained evolutionary algorithm. The main feature of this new approach is that each unit or molecule is treated as a whole body, which drastically reduces the search space and improves the efficiency. The improved method is possibly to be applied in the fields of (1) high pressure phase of simple molecules (H2O, NH3, CH4, etc); (2) pharmaceutical molecules (glycine, aspirin, etc); (3) complex inorganic crystals containing cluster or molecular unit, (Mg(BH4)2, Ca(BH4)2, etc). One application of the constrained evolutionary algorithm is given by the study of (Mg(BH4)2, which is a promising materials for hydrogen storage. Our prediction does not only reproduce the previous work on Mg(BH4)2 at ambient condition, but also yields two new tetragonal structures at high pressure, with space groups P4 and I41/acd are predicted to be lower in enthalpy, by 15.4 kJ/mol and 21.2 kJ/mol, respectively, than the earlier proposed P42nm phase. We have simulated X-ray diffraction spectra, lattice dynamics, and equations of state of these phases. The density, volume contraction, bulk modulus, and the simulated XRD patterns of P4 and I41/acd structures are in excellent agreement with the experimental results. Two kinds of oxides (Xe-O and Mg-O) have been studied under megabar pressures. For XeO, we predict the existence of thermodynamically stable Xe-O compounds at high pressures (XeO, XeO2 and XeO3 become stable at pressures of 83, 102 and 114 GPa, respectively). For Mg-O, our calculations find that two extraordinary compounds MgO2 and Mg3O 2 become thermodynamically stable at 116 GPa and 500 GPa, respectively. Our calculations indicate large charge transfer in these oxides for both systems, suggesting that large electronegativity difference and pressure are the key factors favouring their formations. We also

  18. Light-Propagation Characteristics of Photonic Crystal Waveguide Based on SOI Materials at Different Polarized States

    Institute of Scientific and Technical Information of China (English)

    WANG Chun-Xia; XU Xing-Sheng; LI Fang; DU Wei; XIONG Gui-Guang; LIU Yu-Liang; CHEN Hong-Da

    2006-01-01

    @@ Strgight single-line defect optical waveguides in photonic crystal slabs are designed by the plane wave expansion method and fabricated into silicon-on-insulator (SOI) wafer by 248-nm deep UV lithography.

  19. Structural, optical, thermal and mechanical characterization of an organic nonlinear optical material: 4-methyl-3-nitrobenzoic acid single crystal

    Science.gov (United States)

    Bharathi, M. Divya; Ahila, G.; Mohana, J.; Chakkaravarthi, G.; Anbalagan, G.

    2016-11-01

    Organic single crystals of 4-methyl-3-nitrobenzoic acid (4M3N) have been grown by slow evaporation solution growth technique at room temperature. The single crystal X-ray diffraction study reveals that 4M3N crystallizes in monoclinic system with space group P21/n. The crystalline perfection of the crystal was analyzed by high resolution X-ray diffraction (HRXRD) measurements. The functional groups present in 4M3N have been identified from FT-IR and FT-Raman spectra. The lower cut-off wavelength of 4M3N is found to be 404 nm and the optical band gap is calculated as 2.91 eV. The refractive index shows normal behavior with wavelength. The physio chemical changes, decomposition and stability of the 4M3N compound were established by TG-DTA studies. Vickers microhardness measurement concludes that 4M3N belongs to soft material (n=2.5) category. The LDT value is found to be higher than that of KDP and some of the important organic NLO materials. The third order nonlinear refractive index and nonlinear absorption coefficient of the 4M3N have been measured by Z-scan studies. The imaginary and real parts of the third-order susceptibility values were determined as Im χ3=9.129×10-11 esu and Re χ3=1.4034×10-9 esu respectively. The dislocation density was calculated to be 3.0448×106 cm-2 which indicates the quality of the crystal.

  20. Crystal growth and physical property of Bi-Sb-Te-Se topological insulator materials, and Cu-Bi-Se and Sn-In-Te topological superconductors

    Science.gov (United States)

    Gu, Genda; Yang, Alina; Schneeloch, J.; Zhong, R. D.; Xu, Z. J.; Tranquada, J. M.; Pan, Z. H.; Si, W. D.; Shi, X. Y.; Li, Q.; Valla, T.

    2013-03-01

    The discovery of 3D topological insulator materials and topological superconductor opens up a new research field in the condensed matter physics. We have grown a number of Bi-Sb-Te-Se topological insulator, and Cu-Bi-Se and Sn-In-Te topological superconductor single crystals. We have measured the physical properties on these single crystals. We have studied the effect of growth condition and impurity on the bulk electrical conductivity of these single crystals. We try to answer two questions for the topological insulator materials if it is possible to grow the bulk-insulating topological insulator single crystals and Which maximum resistivity of these topological insulator single crystals we can grow. For the topological superconductor, we have got the bulk superconducting single crystals with a maximum Tc =4.5K. DOE under Contract No. DE-AC02-98CH10886 and the DOE Center for Emergent Superconductivity.

  1. 2010 ARRA Lidar: Hampton County (SC)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Provide high density LiDAR elevation data map of Hampton County, SC. Provide Bare Earth DEM (vegetation removal) of Hampton County, SC.

  2. Magnetic moment of {sup 48}Sc

    Energy Technology Data Exchange (ETDEWEB)

    Ohtsubo, T., E-mail: tohtsubo@np.gs.niigata-u.ac.jp; Kawamura, Y.; Ohya, S. [Niigata University, Department of Physics (Japan); Izumikawa, T. [Niigata University, Radioisotope Center (Japan); Nishimura, K. [Toyama University, Faculty of Engineering (Japan); Muto, S. [Neutron Science Laboratory, KEK (Japan); Shinozuka, T. [Tohoku University, Cyclotron and Radioisotope Center (Japan)

    2007-11-15

    Nuclear magnetic resonances were measured for {sup 48}Sc and {sup 44m}Sc oriented at 8 mK in an Fe host metal. The magnetic hyperfine splitting frequencies at an external magnetic field of 0.2 T were determined to be 63.22(11) MHz and 64.81(1) MHz for {sup 48}Sc and {sup 44m}Sc, respectively. With the known magnetic moment of {mu}({sup 44m}Sc)=+3.88 (1) {mu}{sub N}, the magnetic moment of {sup 48}Sc is deduced as {mu}({sup 44}Sc)=+3.785(12) {mu}{sub N}. The measured magnetic moment of {sup 48}Sc is discussed in terms of the shell model using the effective interactions.

  3. Constitutive Cyclic Deformation Behavior in Single-crystal and Directionally Solidified SSME High-pressure Fuel Turbopump Airfoil Materials

    Science.gov (United States)

    Milligan, W. W.; Huron, E. S.; Antolovich, S. D.

    1985-01-01

    The major goal of the project is to correlate mechanical properties with microstructural deformation behavior and to develop models for constitutive response under a variety of monotonic and cyclic loading cycles, temperatures, strain levels, strain rates, and environments. Two alloys are being studied as candidate SSME turbine blade materials. The first is PWA 1480, which is a single-crystal alloy whose nominal composition is reported. The second alloy being studied is D.S. Mar-M 246 + Hf. This is a directionally solidified material, and its nominal composition is also reported. The major areas of interest for the two materials will be slightly different. The single-crystal alloy lends itself well to fundamental deformation studies, since resolved shear stresses on slip planes are all known and only one grain is present. The D.S. material presents an excellent opportunity to study the effects of slightly misaligned grains on deformation behavior. The two materials will be studied by using approximately the same test matrix, so a good degree of direct comparison will also be possible.

  4. Xemilofiban: SC 54684A, xemlofiban.

    Science.gov (United States)

    2003-01-01

    Xemilofiban [SC 54684, SC 54684A (HCl), xemlofiban], a glycoprotein IIb/IIIa antagonist, is an orally available prodrug of a non-peptide mimetic of the tetrapeptide RGDF. It is converted to the active metabolite, SC 54701 (the free base form of SC 54701A). Development was initiated by Searle (Monsanto). Searle became part of Pharmacia Corporation, which was acquired by, and merged into, Pfizer in April 2003. Searle had co-development and co-marketing agreements with Sankyo in Japan; these have been discontinued. In January 2003, Pharmacia donated the intellectual property for xemilofiban to Western Michigan University. In February 2003, Western Michigan University granted an exclusive worldwide licence of xemilofiban to VDDI Pharmaceuticals (formerly Virtual Drug Development Inc.). Xemilofiban was in a phase III clinical trial, the Evaluation of Xemilofiban in Controlling Thrombotic Events (EXCITE) trial, with Searle (Monsanto) in the US and Europe for the treatment of thrombosis in patients with unstable angina pectoris and acute myocardial infarction undergoing angioplasty. However, as xemilofiban demonstrated no significant clinical benefit, Searle discontinued its development. In Japan, Sankyo discontinued the development of xemilofiban for thrombosis at phase II following Searle's decision to drop the project. VDDI Pharmaceuticals plans to develop xemilofiban in cardiovascular disorders following on from the phase III studies completed by Pharmacia; a restructured dosing schedule and narrowed patient selection will be used. VDDI has research facilities worldwide and will utilise facilities in Ireland for the European clinical development programme; research facilities in the Southwest Michigan Innovation Center are planned while the head office of VDDI is based in Tennessee. Xemilofiban is in phase III development for the treatment of cardiovascular disease in conjunction with percutaneous coronary intervention.

  5. Negative birefraction of acoustic waves in a sonic crystal.

    Science.gov (United States)

    Lu, Ming-Hui; Zhang, Chao; Feng, Liang; Zhao, Jun; Chen, Yan-Feng; Mao, Yi-Wei; Zi, Jian; Zhu, Yong-Yuan; Zhu, Shi-Ning; Ming, Nai-Ben

    2007-10-01

    Optical birefringence and dichroism are classical and important effects originating from two independent polarizations of optical waves in anisotropic crystals. Furthermore, the distinct dispersion relations of transverse electric and transverse magnetic polarized electromagnetic waves in photonic crystals can lead to birefringence more easily. However, it is impossible for acoustic waves in the fluid to show such a birefringence because only the longitudinal mode exists. The emergence of an artificial sonic crystal (SC) has significantly broadened the range of acoustic materials in nature that can give rise to acoustic bandgaps and be used to control the propagation of acoustic waves. Recently, negative refraction has attracted a lot of attention and has been demonstrated in both left-handed materials and photonic crystals. Similar to left-handed materials and photonic crystals, negative refractions have also been found in SCs. Here we report, for the first time, the acoustic negative-birefraction phenomenon in a two-dimensional SC, even with the same frequency and the same 'polarization' state. By means of this feature, double focusing images of a point source have been realized. This birefraction concept may be extended to other periodic systems corresponding to other forms of waves, showing great impacts on both fundamental physics and device applications.

  6. Thermo-optical properties of beryllium containing oxide crystals as materials for high power laser systems

    Science.gov (United States)

    Pestryakov, E. V.; Petrov, V. V.; Trunov, V. I.; Kirpichnikov, A. V.; Laptev, A. V.; Matrosov, V. N.

    2007-06-01

    The elastic and thermo-optical properties of chrysoberyl, beryllium hexaaluminate and beryllium-lanthanum hexaaluminate crystals have been experimentally studied. The velocities of elastic-wave propagation in the crystals are measured by acousto-optic interference method. The values of all the independent components of elastic-constant tensor are determined and used to calculate a number of important dynamic parameters of the crystals such as the Young's and shear moduli, the modulus of volume elasticity, Poisson's ratio, the Debye temperature. Also measurements of refractive indices in 25 - 75 C temperature range in VIS spectral region were performed. Using experimental data the dispersion of thermal optical coefficients (dn/dT) was calculated, these data were employed to evaluate the thermal lens in beryllium containing laser crystals. The experimental and calculated data are compared with similar parameters for well-known laser hosts. Some of beryllium containing oxide crystals was shown to be candidates for master oscillator and amplifying stages of high power femtosecond laser systems.

  7. Crystal structure and mechanical properties of spark plasma sintered Cu2Se: An efficient photovoltaic and thermoelectric material

    Science.gov (United States)

    Tyagi, Kriti; Gahtori, Bhasker; Bathula, Sivaiah; Jayasimhadri, M.; Sharma, Sakshi; Singh, Niraj Kumar; Haranath, D.; Srivastava, A. K.; Dhar, Ajay

    2015-04-01

    Copper selenide (Cu2Se) based materials are currently being investigated globally for efficient photovoltaic and thermoelectric (TE) device applications. Despite having enormous device potential its crystal structure and mechanical properties are still not fully explored owing to its complex behavior. Stereographic projection is one of such useful tools to estimate the crystallography of the material conclusively. In the current study, the crystal structure of α and β-phases of Cu2Se was determined by its stereographic projections in reciprocal space. Further, mechanical properties of Cu2Se are highly important to avoid catastrophic failure and ensure longevity of the TE devices made out of these materials. Cu2Se exhibited the compressive strength of 45 MPa with 3% of plastic strain and a fracture toughness value of 2±0.02 MPa√m, the latter being significantly higher than that of the other known TE materials. Finally, thermal shock resistance, which is one of the crucial parameters for the stability and longevity of the device applications, was calculated to be 281±12 W m-1. Superior mechanical properties coupled with highly reported thermoelectric behavior makes Cu2Se as a potential candidate for green energy generation.

  8. First-principles-based calculations of vibrational normal modes in polyatomic materials with translational symmetry: application to PETN molecular crystal.

    Science.gov (United States)

    Velizhanin, Kirill A; Kilina, Svetlana; Sewell, Thomas D; Piryatinski, Andrei

    2008-10-23

    Numerical studies of vibrational energy transport and associated (non)linear infrared and Raman response in polyatomic materials require knowledge of the multidimensional vibrational potential-energy surface and the ability to perform normal-mode analysis on that potential. The presence of translational symmetry, as in crystals, leads to the observed dispersion of the unit cell normal modes and has to be accounted for in calculations of energy transfer rates and other spectroscopic quantities. Here we report on the implementation of a computational approach that combines the generalized supercell method and density functional theory electronic structure calculations to investigate the vibrational structure in translationally symmetric materials containing relatively large numbers of atoms in the unit cell (58 atoms in the present study). The method is applied to calculate the phonon and vibron dispersion relations and the vibrational density of states in pentaerythritol tetranitrate (PETN) molecular crystal which is an important energetic material. The results set the stage for future investigations of vibrational energy transport and associated nonlinear spectroscopic signatures in this class of materials.

  9. Refractive indices and birefringence of hybrid liquid crystal - nanoparticles composite materials in the terahertz region

    Directory of Open Access Journals (Sweden)

    E. Mavrona

    2015-07-01

    Full Text Available We show that a hybrid LC-ferroelectric nanoparticle suspension of liquid crystal E7 doped with BaTiO3 nanoparticles leads to 10% increase in birefringence in the THz region of spectrum as compared to pure E7. Doped liquid crystals can be used to increase performance of THz modulators and waveplates. BaTiO3 nanoparticles used in the mixture were synthesised with the sol gel technique, and their refractive index has been measured in THz in powder form and in solution.

  10. A dislocation-based crystal viscoplasticity model with application to micro-engineered plasma-facing materials

    Science.gov (United States)

    Rivera, David; Huang, Yue; Po, Giacomo; Ghoniem, Nasr M.

    2017-03-01

    Materials developed with special surface architecture are shown here to be more resilient to the transient thermomechanical environments imposed by intermittent exposures to high heat flux thermal loading typical of long-pulse plasma transients. In an accompanying article, we present experimental results that show the relaxation of residual thermal stresses in micro-engineered W surfaces. A dislocation-based model is extended here within the framework of large deformation crystal plasticity. The model is applied to the deformation of single crystals, polycrystals, and micro-engineered surfaces composed of a uniform density of micro-pillars. The model is utilized to design tapered surface micro-pillar architecture, composed of a Re core and W coatings. Residual stresses generated by cyclic thermomechanical loading of these architectures show that the surface can be in a compressive stress state, following a short shakedown plasma exposure, thus mitigating surface fracture.

  11. Piezoelectric coefficients and spontaneous polarization of ScAlN.

    Science.gov (United States)

    Caro, Miguel A; Zhang, Siyuan; Riekkinen, Tommi; Ylilammi, Markku; Moram, Michelle A; Lopez-Acevedo, Olga; Molarius, Jyrki; Laurila, Tomi

    2015-06-24

    We present a computational study of spontaneous polarization and piezoelectricity in Sc(x)Al(1-x)N alloys in the compositional range from x = 0 to x = 0.5, obtained in the context of density functional theory and the Berry-phase theory of electric polarization using large periodic supercells. We report composition-dependent values of piezoelectric coefficients e(ij), piezoelectric moduli d(ij) and elastic constants C(ij). The theoretical findings are complemented with experimental measurement of e33 for a series of sputtered ScAlN films carried out with a piezoelectric resonator. The rapid increase with Sc content of the piezoelectric response reported in previous studies is confirmed for the available data. A detailed description of the full methodology required to calculate the piezoelectric properties of ScAlN, with application to other complex alloys, is presented. In particular, we find that the large amount of internal strain present in ScAlN and its intricate relation with electric polarization make configurational sampling and the use of large supercells at different compositions necessary in order to accurately derive the piezoelectric response of the material.

  12. Inverse gold photonic crystals and conjugated polymer coated opals for functional materials

    Energy Technology Data Exchange (ETDEWEB)

    Landon, P.B.; Gutierrez, Jose; Ferraris, John P.; Martinez, I.L.; Giridharagopal, Rajiv; Wu, Y.-C.; Lee, Sergey; Parikh, Kunjal; Gillespie, Jessica; Ussery, Geoffrey; Karimi, Behzad; Baughman, Ray; Zakhidov, Anvar; Glosser, R

    2003-10-01

    Inverse gold photonic crystals templated from synthetic opals with a face centered cubic (FCC) crystal lattice were constructed by heat converting gold chloride to metallic gold. Tetrahedral formations constructed of alternating large and small octahedrons oriented in the zinc sulfide structure were created by controlling the infiltration of gold chloride. Silica spheres were coated with polyanilinesulfonic acid, polypyrrole, poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and 5 nm colloidal gold. Ordinary yeast cells were coated with polyanilinesulfonic acid, polypyrrole and 5 nm colloidal gold. Spheres coated with MEH-PPV were dispersed in H{sub 2}O and coated with polyelectrolytes which recharged and sterically stabilized the colloidal surfaces. The recharged spheres self-assembled by sedimentation with a FCC crystalline lattice possessing 500 {mu}m wide and 1 mm long crystallites. Silica spheres with diameters as large as 1500 {mu}m were self-assembled along the [1 0 0] direction of the FCC crystal lattice. Opals infiltrated with gold and opals constructed from polymer coated spheres were co-infiltrated with polypropylene yielding inverse polypropylene composite photonic crystals.

  13. Two-dimensional photonic crystals from semiconductor material with polymer filled holes

    NARCIS (Netherlands)

    Van der Heijden, R.; Kjellander, C.; Carlström, C.-F.; Snijders, J.; Van der Heijden, R.W.; Bastiaansen, K.; Broer, D.; Karouta, F.; Nötzel, R.; Van der Drift, E.

    2006-01-01

    Polymer filling of the air holes of indiumphosphide based two-dimensional photonic crystals is reported. The filling is performed by infiltration with a liquid monomer and solidification of the infill in situ by thermal polymerization. Complete hole filling is obtained with infiltration under ambien

  14. Topology optimized mode conversion in a photonic crystal waveguide fabricated in siliconon-insulator material

    DEFF Research Database (Denmark)

    Frandsen, Lars Hagedorn; Elesin, Yuriy; Frellsen, Louise Floor;

    2014-01-01

    We have designed and for the first time experimentally verified a topology optimized mode converter with a footprint of ∼6.3 μm × ∼3.6 μm which converts the fundamental even mode to the higher order odd mode of a dispersion engineered photonic crystal waveguide. 2D and 3D topology optimization is...

  15. Fundamental Energetic Materials Initiative: Combat Safe Energetic Ingredients Based on Molecular Design and Crystal Morphology

    Science.gov (United States)

    2011-11-30

    loading conditions at the molecular and crystal levels. Replace one of the six bulk commodity chemicals currently used in all military propellant and...tetrazocine (HMX), nitroglycerin (NG), nitrocellulose (NC)) is the only way to achieve IM compliance. B. M. Rice and J. J. Hare, “A Quantum Mechanical

  16. A first-principles study of hydrogen interaction and saturation on ScAl{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Samolia, Madhu [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001 (India); Dhilip Kumar, T.J., E-mail: dhilip@iitrpr.ac.in [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001 (India)

    2013-03-05

    Graphical abstract: Electrostatic potential superimposed on electron density of H{sub 2}, Al{sub 4} and ScAI{sub 3}. Highlights: ► A first principles calculation on hydrogen interaction and saturation on stable ScAl{sub 3} cluster is performed. ► Sc atom has higher negative charge electron density over Al atom in ScAl{sub 3} from natural bond orbital charge analysis. ► H{sub 2} undergoes dissociative chemisorption on the Sc atop site resulting in Sc–H–AI bridge bond. ► H{sub 2} saturation on Sc site results initially in chemisorption and then physisorption with the maximum loading of 6 molecules resulting in stable ScAl{sub 3}H{sub 12} structure. -- Abstract: Complex metal hydrides are promising hydrogen storage material for mobile applications. The presence of scandium catalysts in complex metal hydrides is found to improve significantly the kinetics of H{sub 2} adsorption and desorption. The exact role of these additives is not completely understood. NMR studies suggests the presence of distorted ScAl{sub 3} phase which is attributed to the enhancement of reversible uptake and release rates of H{sub 2}. In this study, we have investigated the hydrogen interaction and saturation on stable ScAl{sub 3} cluster at various sites using the density functional theory by employing unrestricted B3LYP/6-311++G(d,p) and the GGA-PW91/DNP methods. From natural bond orbital charge analysis and electrostatic potential superimposed on electron density plots, ScAl{sub 3} is found to be more polarized and Sc atom in ScAl{sub 3} cluster has higher negative charge and electron density over Al atoms. H{sub 2} undergoes dissociative chemisorption on the Sc atop site in ScAl{sub 3} resulting in Sc–H–Al bridge structure. The hydrogen saturation is studied by sequential H{sub 2} adsorption on ScAl{sub 3} cluster. In the Sc site, the first H{sub 2} molecule undergoes dissociative chemisorption and further addition results in H{sub 2} physisorption with the maximum loading

  17. New self-assembled material based on Ru nanoparticles and 4-sulfocalix[4]arene as an efficient and recyclable catalyst for reduction of brilliant yellow azo dye in water: a new model catalytic reaction

    Science.gov (United States)

    Rambabu, Darsi; Pradeep, Chullikkattil P.; Dhir, Abhimanew

    2016-12-01

    New self-assembled material ( Ru@SC) with ruthenium nanoparticles (Ru NPs) and 4-sulfocalix[4]arene (SC) is synthesized in water at room temperature. Ru@SC is characterized by thermal gravimetric analysis, FT-IR, powder x-ray diffraction, TEM and SEM analysis. The size of Ru nanoparticles in the self-assembly is approximately 5 nm. The self-assembled material Ru@SC shows an efficient catalytic reduction of toxic `brilliant yellow' (BY) azo dye. The reduced amine products were successfully separated and confirmed by single-crystal XRD, NMR and UV-Vis spectroscopy. Ru@SC showed a better catalytic activity in comparison with commercial catalysts Ru/C (ruthenium on charcoal 5 %) and Pd/C (palladium on charcoal 5 and 10 %). The catalyst also showed a promising recyclability and heterogeneous nature as a catalyst for reduction of `BY' azo dye.

  18. Superconductivity at 3.1 K in the orthorhombic ternary silicide ScRuSi

    Science.gov (United States)

    Ruan, Bin-Bin; Wang, Xiao-Chuan; Yu, Jia; Pan, Bo-Jin; Mu, Qing-Ge; Liu, Tong; Chen, Gen-Fu; Ren, Zhi-An

    2017-02-01

    We report the synthesis, crystal structure, superconductivity and physical property characterizations of the ternary equiatomic compound ScRuSi. Polycrystalline samples of ScRuSi were prepared by an arc-melting method. The as-prepared samples were identified as the orthorhombic Co2P-type o-ScRuSi by powder x-ray diffraction analysis. Electrical resistivity measurements show o-ScRuSi to be a metal which superconducts below a T c of 3.1 K; the upper critical field μ 0 H c2(0) is estimated to be 0.87 T. The magnetization and specific heat measurements confirm the bulk type-II superconductivity in o-ScRuSi, with a specific heat jump within the BCS weak coupling limit. o-ScRuSi is the first Co2P-type superconductor to contain scandium. After annealing at 1273 K for a week, o-ScRuSi transforms into hexagonal Fe2P-type h-ScRuSi, which is a Pauli-paramagnetic metal with no superconductivity observed above 1.8 K.

  19. Oxide-cladding aluminum nitride photonic crystal slab: Design and investigation of material dispersion and fabrication induced disorder

    Energy Technology Data Exchange (ETDEWEB)

    Melo, E. G., E-mail: emerdemelo@usp.br; Alvarado, M. A.; Carreño, M. N. P.; Alayo, M. I. [Electronic Systems Engineering Department, University of São Paulo, CEP 05508-010 São Paulo, SP (Brazil); Carvalho, D. O. [UNESP - São Paulo State University, CEP 13874-149 São João da Boa Vista, SP (Brazil); Ferlauto, A. S. [Department of Physics, Federal University of Minas Gerais, CEP 31270-901 Belo Horizonte, MG (Brazil)

    2016-01-14

    Photonic crystal slabs with a lower-index material surrounding the core layer are an attractive choice to circumvent the drawbacks in the fabrication of membranes suspended in air. In this work we propose a photonic crystal (PhC) slab structure composed of a triangular pattern of air holes in a multilayer thin film of aluminum nitride embedded in silicon dioxide layers designed for operating around 450 nm wavelengths. We show the design of an ideal structure and analyze the effects of material dispersion based on a first-order correction perturbation theory approach using dielectric functions obtained by experimental measurements of the thin film materials. Numerical methods were used to investigate the effects of fabrication induced disorder of typical nanofabrication processes on the bandgap size and spectral response of the proposed device. Deviation in holes radii and positions were introduced in the proposed PhC slab model with a Gaussian distribution profile. Impacts of slope in holes sidewalls that might result from the dry etching of AlN were also evaluated. The results show that for operation at the midgap frequency, slope in holes sidewalls is more critical than displacements in holes sizes and positions.

  20. PbSc0.5Ta0.5O3 pyroelectric materials and their application in pyroelectric detector arrays%PbSc0.5Ta0.5O3热释电材料及其红外探测器列阵

    Institute of Scientific and Technical Information of China (English)

    于光龙; 肖定全; 朱建国; 余萍; 袁小武

    2003-01-01

    热释电红外探测器具有探测波长范围广、室温工作、无需致冷等优点.近年来,工作于介电方式下的PbSc0.5Ta0.5O3 (PST)热释电材料由于具有热释电系数大,热释电探测优值高等特点,成为热释电应用研究的热点之一.本文综述了目前PST热释电陶瓷材料的介电,热释电性能及其探测器列阵的发展.由于小型化的要求,PST薄膜亦倍受关注,因此本文还对目前PST热释电薄膜的制备方法,薄膜的热释电、介电性能及薄膜型探测器结构和发展进行了概述.

  1. Synthesis and Reaction of [MnRe(CO)6(μ-SH)(μ-SC(H)PPri3)(PPh3)

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The synthesis, the crystal structure and the reaction of the hetero-binuclear complex [MnRe(CO)6(μ-SH)(μ-SC(H)PPri3)(PPh3)] are reported. The results of single crystal X-ray structure analysis showed that the fragments Mn(CO)3 and Re(CO)3 were bridged by SH and SC(H)PPri3. The title complexes can react with BunLi and RX forming complexes MnRe(CO)6(μ-SR)(μ-SC(H)PPri3)(PPh3) (R = Me, CH2CH=CH2, SnBu3n).

  2. Synthesis, growth, structural, spectral, thermal, chemical etching, linear and nonlinear optical and mechanical studies of an organic single crystal 4-chloro 4-nitrostilbene (CONS): a potential NLO material.

    Science.gov (United States)

    Dinakaran, Paul M; Kalainathan, S

    2013-07-01

    4-Chloro 4-nitrostilbene (CONS) a new organic nonlinear optical material has been synthesized. Employing slow evaporation method, good optical quality single crystals (dimensions up to 6×2×3 mm(3)) have been grown using ethyl methyl ketone (EMK) as a solvent. The grown crystals have been subjected to various characterizations such as single crystal X-ray diffraction, powder XRD, Fourier Transform Infrared spectroscopy (FTIR), proton NMR, solid UV absorption, SHG studies. Single crystal X-ray diffraction reveals that the crystal system belongs to monoclinic with noncentrosymmetric space group P21. The UV-Vis absorption spectrum has been recorded and found that the cut off wavelength is 380 nm. Functional groups and the structure of the title compound have been confirmed by FTIR and (1)H NMR spectroscopic analyses respectively. Molecular mass of the CONS confirmed by the high resolution mass spectral analysis .The thermal behavior of the grown crystal has been studied by TG/DTA analysis and it shows the melting point is at 188.66 °C. Dislocations and growth pattern present in the grown crystal revealed by the etching study. The mechanical strength of the CONS crystal has been studied by Vicker's hardness measurement. The SHG efficiency of the grown crystal has been determined by Kurtz and Perry powder test which revealed that the CONS crystal (327 mV) has 15 times greater efficiency than that of KDP (21.7 mV).

  3. Synthesis, growth, structural, spectral, thermal, chemical etching, linear and nonlinear optical and mechanical studies of an organic single crystal 4-chloro 4-nitrostilbene (CONS): A potential NLO material

    Science.gov (United States)

    Dinakaran, Paul M.; Kalainathan, S.

    2013-07-01

    4-Chloro 4-nitrostilbene (CONS) a new organic nonlinear optical material has been synthesized. Employing slow evaporation method, good optical quality single crystals (dimensions up to 6 × 2 × 3 mm3) have been grown using ethyl methyl ketone (EMK) as a solvent. The grown crystals have been subjected to various characterizations such as single crystal X-ray diffraction, powder XRD, Fourier Transform Infrared spectroscopy (FTIR), proton NMR, solid UV absorption, SHG studies. Single crystal X-ray diffraction reveals that the crystal system belongs to monoclinic with noncentrosymmetric space group P21. The UV-Vis absorption spectrum has been recorded and found that the cut off wavelength is 380 nm. Functional groups and the structure of the title compound have been confirmed by FTIR and 1H NMR spectroscopic analyses respectively. Molecular mass of the CONS confirmed by the high resolution mass spectral analysis .The thermal behavior of the grown crystal has been studied by TG/DTA analysis and it shows the melting point is at 188.66 °C. Dislocations and growth pattern present in the grown crystal revealed by the etching study. The mechanical strength of the CONS crystal has been studied by Vicker's hardness measurement. The SHG efficiency of the grown crystal has been determined by Kurtz and Perry powder test which revealed that the CONS crystal (327 mV) has 15 times greater efficiency than that of KDP (21.7 mV).

  4. Dielectric technique to measure the twist elastic constant of liquid crystals: the case of a bent-core material.

    Science.gov (United States)

    Salamon, P; Eber, N; Seltmann, J; Lehmann, M; Gleeson, J T; Sprunt, S; Jákli, A

    2012-06-01

    The effect of director pretilt on the twist magnetic Fréedericksz transition of nematics was investigated in a planar cell. The director configuration was calculated as a function of magnetic inductance. The dielectric and optical response of the nematic liquid crystal was numerically modeled. A dielectric measurement method for determining the elastic constant K_{22} is presented. The influence of the conditions for the Mauguin effect is discussed. The theoretical predictions were confirmed by our experiments. Experimental data for all elastic constants of a bent-core nematic material are presented and discussed.

  5. Optical properties of opaline photonic crystals covered by phase-change material Ge$_2$Sb$_2$Te$_5$

    CERN Document Server

    Dyakov, Sergey A; Voronov, Mikhail M; Yakovlev, Sergey A; Pevtsov, Alexander B; Akimov, Ilya A; Tikhodeev, Sergei G

    2016-01-01

    Reflection spectra from 3D opaline photonic crystals covered with phase-change material Ge$_2$Sb$_2$Te$_5$ are studied for different incident angles of light both experimentally and theoretically. We demonstrate that in presence of Ge$_2$Sb$_2$Te$_5$ chalcogenide capping layer, the reflection spectra have peaks associated with resonant Wood's anomalies. The experimental reflection spectra are in a good agreement with theoretical calculations performed by the Fourier modal method in the scattering matrix form. The electromagnetic near-field distributions of incident light at resonant frequencies are calculated.

  6. Transmission properties of one-dimensional Photonic crystals containing double-negative and single-negative materials

    Institute of Scientific and Technical Information of China (English)

    Xia Li; Kang Xie; Haiming Jiang

    2008-01-01

    The transmission properties of one-dimensional photonic crystals containing double-negative and singlenegative materials are studied theoretically.A special kind of photonic band gap is found in this structure.This gap is invariant with scaling and insensitive to thickness fluctuation.But when changing the ratio of the thickness of two media.the width of the gap could be enlarged.The defect modes are analyzed by inducing a linear defect layer in the structure.It is found that the number of defect modes will increase when the thickness of the defect layer becomes larger.

  7. Faradaic current in different mullite materials. Single crystal, ceramic and cermets

    Energy Technology Data Exchange (ETDEWEB)

    Mata-Osoro, Gustavo; Moya, Jose S.; Pecharroman, Carlos [Instituto de Ciencia de Materiales de Madrid (CSIC) (Spain); Morales, Miguel [Universidad de Santiago de Compostela (Spain). LabCaF; Diaz, L. Antonio [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN-CSIC), Llanera (Spain); Schneider, Hartmut [Koeln Univ. (Germany). Inst. fuer Kristallographie

    2012-04-15

    Faradaic current measurements have been carried out on three different types of mullite: 2: 1 mullite single crystals (E perpendicular to c), 3: 2 ceramics and 11 % mullite/Mo composites. Measurements were carried out on very thin samples (60 {mu}m) at high voltages (500 to 1 000 V). Under these conditions, measurable currents were recorded even at room temperature. Results indicate notable differences between these three samples, which suggest that, although they share the same name and similar crystalline structure, binding energies and defect distributions seem to be very different. Finally, it has been seen that the excellent behaviour against dielectric breakdown of ceramic mullite does not hold for single crystals or mullite based cermets. (orig.)

  8. Synthesis, Crystal Structure, and Comparative Study of a New Organic Material 3,4-Diaminobenzophenone Semihydrate

    Directory of Open Access Journals (Sweden)

    Tarek Ben Rhaiem

    2013-01-01

    Full Text Available The new organic 3,4-diaminobenzophenone semihydrate (34ABPH is grown by slow evaporation method. The compound crystallizes in the monoclinic space group: C2. The unit cell dimensions are (8 Å, (2 Å, (10 Å, and β = 99.40 (2° with . The crystal structure analysis reveals that the C13H12N2O molecules chains are organized into a double ribbon in the (b,c plane. The structural components interact by N–H⋯O and O–H⋯O hydrogen bonds, building up a two-dimensional network. The presence of functional groups in the molecular structure is confirmed by the Fourier transform infrared (FT-IR spectroscopy. Thermogravimetric analysis (TGA confirms the presence of the water molecule.

  9. Neutron scattering as a probe of liquid crystal polymer-reinforced composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Hjelm, R.P.; Douglas, E.P.; Benicewicz, B.C.; Langlois, D.A.

    1995-12-31

    This is the final report of a three-year Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This research project sought to obtain nanoscale and molecular level information on the mechanism of reinforcement in liquid crystal polymer (LCP)-reinforced composites, to realize molecular-reinforced LCP composites, and to test the validity of the concept of molecular reinforcement. Small-angle neutron scattering was used to study the structures in the ternary phase diagram of LCP with liquid crystal thermosets and solvent on length scales ranging from 1-100 nm. The goal of the scattering measurements is to understand the phase morphology and degree of segregation of the reinforcing and matrix components. This information helps elucidate the physics of self assembly in these systems. This work provides an experimental basis for a microengineering approach to composites of vastly improved properties.

  10. Optical characterization and crystal field calculations for some erbium based solid state materials for laser refrigeration

    Science.gov (United States)

    Hasan, Z.; Qiu, Z.; Johnson, Jackie; Homerick, Uwe

    2009-02-01

    The potential of three erbium based solids hosts has been investigated for laser cooling. Absorption and emission spectra have been studied for the low lying IR transitions of erbium that are relevant to recent reports of cooling using the 4I15/2-4I9/2 and4I15/2 -4I13/2 transitions. Experimental studies have been performed for erbium in three hosts; ZBLAN glass and KPb2Cl5 and Cs2NaYCl6 crystals. In order to estimate the efficiencies of cooling, theoretical calculations have been performed for the cubic Elpasolite (Cs2NaYCl6 ) crystal. These calculations also provide a first principle insight into the cooling efficiency for non-cubic and glassy hosts where such calculations are not possible.

  11. δ-BIBO:Nd crystals as promising laser operated piezoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Majchrowski, A.; Jaroszewicz, L.R. [Institute of Applied Physics, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland); Kityk, I.V., E-mail: iwank74@gmail.com [Electrical Engineering Faculty, Czestochowa University Technology, 42-201, Armii Krajowej 17 (Poland)

    2015-01-25

    Highlights: • Novel laser stimulated effects were discovered in δ-BiB{sub 3}O{sub 6} crystals. • Effect is caused by localized levels of the Nd{sup +3} ions. • The photoinduced piezoelectricity is maximal for the simultaneous treatment by 1064 nm and 532 nm laser beams. - Abstract: A possibility to operate piezoelectric efficiency of δ-BIBO:Nd crystals using external nanosecond laser light at 1064 nm and 532 nm was shown. Depending on the kind of the photoexciting light the behavior of the output piezoelectricity was quite different. The measurements of temperature and temporary features for the photoinduced piezoelectricity confirmed the main role of the incorporation of Nd ions in the δ-BiB{sub 3}O{sub 6} structure with respect to piezoelectricity. The DFT simulations of the local charge density re-distribution were done using the norm-conserving pseudopotential method to confirm principal role of the space charge density redistribution.

  12. Crystal structure of the high-energy-density material guanylurea dipicrylamide

    Directory of Open Access Journals (Sweden)

    Raik Deblitz

    2014-08-01

    Full Text Available The title compound, 1-carbamoylguanidinium bis(2,4,6-trinitrophenylamide [H2NC(=ONHC(NH22]+[N{C6H2(NO23-2,4,6}2]− (= guanylurea dipicrylamide, was prepared as dark-red block-like crystals in 70% yield by salt-metathesis reaction between guanylurea sulfate and sodium dipicrylamide. In the solid state, the new compound builds up an array of mutually linked guanylurea cations and dipicrylamide anions. The crystal packing is dominated by an extensive network of N—H...O hydrogen bonds, resulting in a high density of 1.795 Mg m−3, which makes the title compound a potential secondary explosive.

  13. Crystal structure of the high-energy-density material guanylurea dipicryl-amide.

    Science.gov (United States)

    Deblitz, Raik; Hrib, Cristian G; Hilfert, Liane; Edelmann, Frank T

    2014-08-01

    The title compound, 1-carbamoylguanidinium bis-(2,4,6-tri-nitro-phen-yl)amide [H2NC(=O)NHC(NH2)2](+)[N{C6H2(NO2)3-2,4,6}2](-) (= guanylurea dipicryl-amide), was prepared as dark-red block-like crystals in 70% yield by salt-metathesis reaction between guanylurea sulfate and sodium dipicryl-amide. In the solid state, the new compound builds up an array of mutually linked guanylurea cations and dipicryl-amide anions. The crystal packing is dominated by an extensive network of N-H⋯O hydrogen bonds, resulting in a high density of 1.795 Mg m(-3), which makes the title compound a potential secondary explosive.

  14. Two-dimensional photonic crystals from semiconductor material with polymer filled holes

    Science.gov (United States)

    van der Heijden, Rob; Kjellander, Charlotte; Carlström, Carl-Fredrik; Snijders, Juri; van der Heijden, Rob W.; Bastiaansen, Kees; Broer, Dick; Karouta, Fouad; Nötzel, Richard; van der Drift, Emile; Salemink, Huub W. M.

    2006-04-01

    Polymer filling of the air holes of indiumphosphide based two-dimensional photonic crystals is reported. The filling is performed by infiltration with a liquid monomer and solidification of the infill in situ by thermal polymerization. Complete hole filling is obtained with infiltration under ambient pressure. This conclusion is based both on cross-sectional scanning electron microscope inspection of the filled samples as well as on optical transmission measurements.

  15. A review on solar cells from Si-single crystals to porous materials and quantum dots

    OpenAIRE

    Badawy, Waheed A.

    2013-01-01

    Solar energy conversion to electricity through photovoltaics or to useful fuel through photoelectrochemical cells was still a main task for research groups and developments sectors. In this article we are reviewing the development of the different generations of solar cells. The fabrication of solar cells has passed through a large number of improvement steps considering the technological and economic aspects. The first generation solar cells were based on Si wafers, mainly single crystals. P...

  16. Bioinspired High-Performance Energetic Materials Using Heme-Containing Crystals.

    Science.gov (United States)

    Slocik, Joseph M; Drummy, Lawrence F; Dickerson, Matthew B; Crouse, Christopher A; Spowart, Jonathan E; Naik, Rajesh R

    2015-08-05

    Synthetic hemozoin crystals (β-hematin) are assembled with aluminium nanoparticles (nAl) to create a nanomaterial composite that is highly energetic and reactive. The results here demonstrate that hemozoin rapidly oxidizes the nAl fuel to release large amounts of energy (+12.5 ± 2.4 kJ g(-1) ). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Methane-propane hydrate crystal growth in the presence of nanosized materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M.S.; Ryu, Y.B.; Kim, Y.S.; Lee, J.D. [Korea Inst. of Industrial Technology, Busan (Korea, Republic of). Busan Research Center; Park, Y.H. [Pusan National Univ., Busan (Korea, Republic of)

    2008-07-01

    The impact of nano-sized titanium dioxide, silver, and silica (TiO{sub 2}-Ag-SiO{sub 2}) sols on the gas hydrate formation morphology within an enclosed cell partially filled with liquid water was investigated. The nano-sized particles were synthesized suing a modified sol-gel method with a reduction agent added to eliminate the need for auxiliary dispersants or surfactants. Structure 2 (s2) hydrates were synthesized using a gas mixture of 90.1 per cent methane and propane as guest molecules. Small amounts of the nano-sized sols were added to the liquid water. The aim of the study was to determine methods of ensuring the stability of methane hydrates in storage facilities and during transport using gas to solids technology (GTS). Nucleation, hydrate crystal growth, and the migration of the gas hydrate were studied in relation to the stationary interface between the liquid water and the gas. Results of the study showed that the hydrate's growth phase started with the formation of a film at the upper surface of the liquid water pool. Crystals then grew in a downward manner from the hydrate film. Video images of the crystals showed that the downward crystals grown in the presence of the nano-sized particles occurred at a faster rate and with finer arm spacing. It was concluded that the addition of the nano-particles provided a larger specific surface area and larger nucleation sides so that more gas was absorbed into the water. The TiO{sub 2}-Ag-SiO{sub 2} sols acted as a promoter for methane-propane hydrate formation. 5 refs., 4 figs.

  18. Multiscale Modeling of Structurally-Graded Materials Using Discrete Dislocation Plasticity Models and Continuum Crystal Plasticity Models

    Science.gov (United States)

    Saether, Erik; Hochhalter, Jacob D.; Glaessgen, Edward H.

    2012-01-01

    A multiscale modeling methodology that combines the predictive capability of discrete dislocation plasticity and the computational efficiency of continuum crystal plasticity is developed. Single crystal configurations of different grain sizes modeled with periodic boundary conditions are analyzed using discrete dislocation plasticity (DD) to obtain grain size-dependent stress-strain predictions. These relationships are mapped into crystal plasticity parameters to develop a multiscale DD/CP model for continuum level simulations. A polycrystal model of a structurally-graded microstructure is developed, analyzed and used as a benchmark for comparison between the multiscale DD/CP model and the DD predictions. The multiscale DD/CP model follows the DD predictions closely up to an initial peak stress and then follows a strain hardening path that is parallel but somewhat offset from the DD predictions. The difference is believed to be from a combination of the strain rate in the DD simulation and the inability of the DD/CP model to represent non-monotonic material response.

  19. Electro-Thermal Tuning in a Negative Dielectric Cholesteric Liquid Crystal Material

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan,L.; Wofford, J.; Tondiglia, V.; Sutherland, R.; Koerner, H.; Vaia, R.; Bunning, T.

    2008-01-01

    The thermal and electrical tunability of a cholesteric liquid crystal containing a negative dielectric anisotropy liquid crystal in a planar alignment was studied. The physical, optical, and electro-optical characteristics of mixtures containing different ratios of chiral dopant S811 and the negative dielectric anisotropy liquid crystal ZLI-2806 were examined. A smectic A phase was seen at room temperature for S811 loadings >20 wt%. Below 20%, a room temperature cholesteric phase was observed. Upon heating mixtures with composition S811 >20%, the selective reflection notch of the cholesteric phase appeared and blueshifted with temperature. Thermal tuning from 2300?to?500?nm was observed over the temperature range of 23-55? C. Polarized optical microscopy, differential scanning calorimetry, and x-ray studies were utilized to confirm the temperature-dependent phase behavior. Tuning of ? 50?nm by the application of a direct current electric field was also observed with no onset of electrohydrodynamic instabilities for voltages up to {approx} 300 V. Bandwidth broadening but not tuning was obtained with the application of alternating current fields. Electrical tuning is likely due to pitch contraction brought about through the annealing of defects.

  20. Structure of singly terminated DyScO3 (110) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kleibeuker, Josee [University of Twente, Enschede, Netherlands; Kuiper, Bouwe [University of Twente, Enschede, Netherlands; Harkema, S. [University of Twente, Enschede, Netherlands; Blank, Dave H. A. [University of Twente, Enschede, Netherlands; Koster, Gertjan [University of Twente, Enschede, Netherlands; Rijnders, Guus [MESA+ University of Twente, Enschede, Netherlands; Tinnemans, P. [Radboud University Nijmegen, The Netherlands; Vlieg, E. [Radboud University Nijmegen, The Netherlands; Rossen, P. B. [University of California, Berkeley; Siemons, Wolter [ORNL; Portale, G. [European Synchrotron Radiation Facility (ESRF); Ravichandran, Jayakanth [University of California, Berkeley; Ramesh, R. [University of California, Berkeley

    2012-01-01

    We have studied the polar surface of singly terminated DyScO{sub 3} (110) crystals by reflective high-energy electron diffraction, surface x-ray diffraction and angle-resolved mass spectroscopy of recoiled ions. These techniques show that the surfaces are (1 x 1) reconstructed, which points to the absence of ordered cation vacancies at the surface. The best surfaces were obtained after a selective chemical wet etch. We suggest that for ScO{sub 2} terminated surfaces, adsorbates, or oxygen vacancies are most likely to occur in order to overcome the polarity difference between stoichiometric bulk crystal and vacuum.

  1. Photoluminescence of CdTe Crystals Grown by Contactless PVT Method

    Science.gov (United States)

    Palosz, W.; Grasza, K.; Cui, Y.; Wright, G.; Roy, U. N.; Burger, A.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    High quality CdTe crystals with resistivities higher than 10(exp 8) Omega cm were grown by the 'contactless' PVT (physical vapor transport) technique. Group III elements In and Al, and the transition metal Sc were introduced at the nominal level of about 6 ppm to the source material. Low-temperature photoluminescence (PL) has been employed to identify the origins of PL emissions of the crystals. It was found that the emission peaks at 1.584 eV and 1.581 eV exist only in the In-doped crystal. The result suggests that the luminescence line at 1.584 eV is associated with Cd-vacancy/indium complex. The intensity of the broadband centered at 1.43 eV decreases dramatically with introduction of Sc.

  2. Organic salts of biguanide - An attempt to crystal engineering of novel materials for second harmonic generation

    Science.gov (United States)

    Matulková, Irena; Němec, Ivan; Císařová, Ivana; Němec, Petr; Vaněk, Přemysl

    2010-03-01

    Three organic salts of biguanide with oxalic, succinic and L-tartaric acids have been prepared and X-ray structural analysis has been performed. Biguanidium(1+) oxalate hemihydrate ( a = 6.8330(2) Å, b = 10.0430(2) Å, c = 14.6230(4) Å, α = 90.236(1) , β = 90.333(1) , γ = 105.605(2) , V = 966.46(4) Å 3, Z = 1, R = 0.0393 for 3704 observed reflections) and biguanidium(1+) hydrogen succinate ( a = 6.4600(1) Å, b = 6.7670(2) Å, c = 11.4150(3) Å, α = 91.822(1) , β = 105.312(1) , γ = 90.922(1) , V = 480.89(2) Å 3, Z = 2, R = 0.0357 for 1880 observed reflections) belong to the triclinic space group P 1¯. Their crystal structures are based on biguanidium(1+) pairs connected by intermolecular N-H⋯N hydrogen bonds. The remaining ions (eventually water molecules) form a 3D structural network with these pairs. Furthermore, the formation of the cationic and anionic layers interconnected by intermolecular N-H⋯O hydrogen bonds was observed in the crystal structure of biguanidium(1+) hydrogen succinate. Biguanidium(2+) L-tartrate crystallizes in the orthorhombic space group P 2 12 12 1 ( a = 6.7170(2) Å, b = 9.2740(2) Å, c = 16.1500(4) Å, V = 1006.04(4) Å 3, Z = 4, R = 0.0432 for 2193 observed reflections). The crystal structure is based on L-tartrate chains, which are interconnected by isolated biguanidium(2+) cations via several types of N-H⋯O hydrogen bonds. The formation of L-tartrate chains is mediated by two types of intermolecular O-H⋯O hydrogen bonds connecting the hydroxyl and carboxylate groups. The FTIR and FT Raman spectra of all the compounds were recorded and discussed. The theoretical values of the first hyperpolarizability components were calculated for biguanidium(1+) and biguanidium(2+) cations at the B3LYP level with the 6-311G(d,p) basis set. Quantitative measurements of the second harmonic generation of powdered biguanidium(2+) L-tartrate at 800 nm were performed and a relative efficiency of 2% (compared to KDP) was

  3. Effects of loss factors on zero permeability and zero permittivity gaps in 1D photonic crystal containing DNG materials

    CERN Document Server

    Aghajamali, Alireza; Barati, Mahmood

    2014-01-01

    The effects of electric and magnetic loss factors on zero-mu and zero-epsilon gaps in a one-dimensional lossy photonic crystal composed of double-negative and double-positive materials are theoretically investigated by employing the characteristic matrix method. This study contradicts the previous reports as it indicates that by applying the inevitable factors of electric and magnetic losses to the double-negative material, the zero-mu and zero-epsilon gaps appear simultaneously in the transmission spectrum, being independent of the incidence angle and polarizations. Moreover, the results show that these gaps appear not only for an oblique incidence but also in the case of normal incidence, and their appearance at the normal incidence is directly related to the magnetic and electric loss factors. Besides, the results indicate that as the loss factors and angle of incidence increase, the width of both gaps also increases.

  4. Luminescent hybrid materials based on zeolite L crystals and lanthanide complexes: host-guest assembly and ultraviolet-visible excitation.

    Science.gov (United States)

    Chen, Lei; Yan, Bing

    2014-10-15

    Several kinds of host-guest hybrid materials have been synthesized employing a ship in a bottle method by loading 9-hydroxy-2-methylphenalenone (MHPO) or 9-hydroxyphenalen (HPNP) from gas phase into the nanochannels of Ln(3+)-exchanged zeolite L (ZL) crystals (Ln=Gd or Eu). The resulting hybrids without lanthanide ions, MHPO-ZL, HPNP-ZL and the hybrids with lanthanide ions Ln-MHPO-ZL and Ln-HPNP-ZL are characterized with FT-IR, UV-vis DRS and photoluminescence spectroscopy. The photoluminescence properties of these hybrid materials have been analyzed and discussed, exhibiting the luminescence of Eu(3+) and ligands under the excitation at ultraviolet-visible region. These results provide useful data and can be expected to have potential application in the practical fields. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Nanocomposite Material Based on GaSe and InSe Layered Crystals Intercalated by RbNO3 Ferroelectric

    Directory of Open Access Journals (Sweden)

    Z.R. Kudrynskyi

    2013-10-01

    Full Text Available In the present study, we established for the first time that single-crystal samples of gallium GaSe and indium InSe selenides can be intercalated by molecules of RbNO3 ferroelectric salt rubidium nitrate. We investigated kinetics of the intercalation process at different temperature-time regimes. Structural properties of the intercalate nanocomposites were studied by X-ray diffraction. The studied structures can be presented as composite superlattices which consist of a lattice of anisotropic layered semiconductor with embedded ferroelectric layers. We established that GaSe nanocomposite material exhibits electric energy storage properties. Energy storage properties are associated with polarization of the intercalated ferroelectric under external electric field. We developed a solid state electric energy storage device on the basis of GaSe nanocomposite material.

  6. Full solution, for crystal class 3m, of the Holland-EerNisse complex material-constant theory of lossy piezoelectrics for harmonic time dependence.

    Science.gov (United States)

    Piquette, Jean C; McLaughlin, Elizabeth A

    2007-06-01

    A complex material-constant theory of lossy piezoelectrics is fully solved for crystal class 3m for harmonic time dependence of the fields and stresses. A new demonstration that the theory's eigen coupling factor equation applies to the lossy alternating current (AC) case also is given. The solution presented for crystal class 3m provides a complete orthonormal set of eigenvectors and eigenvalues for the eigen coupling factor problem, and it also provides a complete orthonormal set of eigenvectors and eigenvalues for the eigen loss tangent problem, for this crystal class. It is shown that two positive coupling factors are sufficient to express an arbitrary 3m crystal state. Despite the complex nature of the material constants, the Holland-EerNisse theory produces fully real expressions for the coupling factors. The loss tangent eigenvalues also are fully real and positive. The loss eigenstates are important because driving a crystal in a loss eigenstate tends to minimize the impact of material losses. Given also is a set of loss inequalities for crystal class 3m. The loss inequalities of crystal class 6mm are recovered from these when d22 and s(E)14 both vanish.

  7. Main: 3SC2 [RPSD[Archive

    Lifescience Database Archive (English)

    Full Text Available 3SC2 小麦 Bread Wheat Triticum aestivum Serine Carboxypeptidase Ii Chains A And B Nam... 1WHS; X-ray; A=6-260, B=266-418.|PDB; 1WHT; X-ray; A=5-260, B=266-418.|PDB; 3SC2; X-ray; A=1-259, B=266-417...WHDAPRSMLPIYRELIAAGLRIWVFSGDTDAVVPLTATRYSIGALGLPTTTSWYPWYDDQEVGGWSQVYKGLTLVSVRGAGHEVPLHRPRQALVLFQYFLQGKPMPGQTKNAT wheat_3SC2.jpg ...

  8. Ultrawide low frequency band gap of phononic crystal in nacreous composite material

    Energy Technology Data Exchange (ETDEWEB)

    Yin, J.; Huang, J.; Zhang, S., E-mail: zhangs@dlut.edu.cn; Zhang, H.W.; Chen, B.S.

    2014-06-27

    The band structure of a nacreous composite material is studied by two proposed models, where an ultrawide low frequency band gap is observed. The first model (tension-shear chain model) with two phases including brick and mortar is investigated to describe the wave propagation in the nacreous composite material, and the dispersion relation is calculated by transfer matrix method and Bloch theorem. The results show that the frequency ranges of the pass bands are quite narrow, because a special tension-shear chain motion in the nacreous composite material is formed by some very slow modes. Furthermore, the second model (two-dimensional finite element model) is presented to investigate its band gap by a multi-level substructure scheme. Our findings will be of great value to the design and synthesis of vibration isolation materials in a wide and low frequency range. Finally, the transmission characteristics are calculated to verify the results. - Highlights: • A Brick-and-Mortar structure is used to discuss wave propagation through nacreous materials. • A 1D Bloch wave solution of nacreous materials with a tension-shear chain model is obtained. • The band structure and transmission characteristics of nacreous materials with the FE model are examined. • An ultrawide low frequency band gap is found in nacreous materials with both theory and FE model.

  9. Progress in the material development of LiCaAlF(6):Cr(3+) laser crystals

    Science.gov (United States)

    Shinn, M. D.; Chase, L. L.; Caird, J. A.; Payne, S. A.; Atherton, L. J.; Kway, W. L.

    1990-03-01

    High Cr(3+) doping levels, up to 8 mole percent, and low losses were obtained with the tunable solid-state laser material LiCaAlF(6):Cr(3+) (Cr:LiCAF). Measurements and calculations show that high pumping and extraction efficiencies are possible with the improved material.

  10. Photonic crystal vertical-cavity surface-emitting laser based on GaAs material

    Institute of Scientific and Technical Information of China (English)

    XU XingSheng; WANG ChunXia; SONG Qian; DU Wei; HU HaiYang; ZHAO ZhiMin; LU Lin; KAN Qiang; CHEN HongDa

    2007-01-01

    A photonic crystal vertical-cavity-surface-emitting laser (PC-VCSEL) with a wavelength of about 850 nm was realized. The direct-current electrically-driven PC-VCSELs with a minimum threshold current of 2 mA and a maximum threshold current of 13.5 mA were obtained. We fabricated a series of PC-VCSEL chips whose lattice constants are in the range from 0.5 to 3 ?m with different filling factors, and found that the laser characterization depends on the lattice constant, the filling factor, the size of cavity, etc.

  11. High-efficient physical adsorption and detection of formaldehyde using Sc- and Ti-decorated graphdiyne

    Science.gov (United States)

    Chen, Xi; Gao, Pengfei; Guo, Lei; Wen, Yanni; Fang, Dangqi; Gong, Baihua; Zhang, Yang; Zhang, Shengli

    2017-03-01

    In sensitive analysis, the ultimate limit is to achieve reliable detection on trace amount of molecules. In this work, Sc- and Ti-decorated graphdiyne were proposed as promising materials for high-efficient molecular detection. Using density functional theory calculations, we investigated the electronic response of single Sc- and Ti-atom-decorated graphdiyne to HCHO (as a typical air pollutant). Thermodynamic analysis predicted that Sc or Ti adatom could be stabilized on the corner sites of single-layer graphdiyne sheet, with migration barriers high enough to prevent Sc or Ti adatom aggregation. The adsorption of HCHO on Sc- or Ti-decorated graphdiyne was found stronger than on pristine graphene or graphdiyne, which provides a prerequisite for molecular sensing. The electronegativity of HCHO leads to strong electronic attraction from Sc or Ti adatom to HCHO, resulting in a remarkable decrease of carrier density in graphdiyne. On Ti-decorated graphdiyne, the electronic attraction of HCHO appears to be stronger than on Sc-decorated graphdiyne and changes the system from metal to n-doped semiconductor. Quantum transport calculations show a decrease of current caused by the adsorbed HCHO. The results systematically exhibit the electronic response of Sc- or Ti-decorated graphdiyne to HCHO and suggest them as promising materials for molecule detection.

  12. Crystal structure and thermochemical properties of bis(1-octylammonium) tetrachlorochromate phase change materials

    Institute of Scientific and Technical Information of China (English)

    Lu Dong-Fei; Di You-Ying; He Dong-Hua

    2012-01-01

    A new crystalline complex (C8H17NH3)2CdCl4 (s) (abbreviated as CsCd(s)) is synthesized by liquid phase reaction.The crystal structure and composition of the complex are determined by single crystal X-ray diffraction,chemical analysis,and elementary analysis.It is triclinic,the space group is P-1 and Z =2.The lattice potential energy of the title complex is calculated to be UpoT (CsCd(s))=978.83 kJ.mol-1 from crystallographic data.Low-temperature heat capacities of the complex are measured by using a precision automatic adiabatic calorimeter over a temperature range from 78 K to 384 K.The temperature,molar enthalpy,and entropy of the phase transition for the complex are determined to be 307.3±0.15 K,10.15±0.23 kJ.mol-1 and 33.05±0.78 J.K-1.mo1-1 respectively for the endothermic peak.Two polynomial equations of the heat capacities each as a function of temperature are fitted by using the leastsquare method.Smoothed heat capacity and thermodynamic functions of the complex are calculated based on the fitted polynomials.

  13. Hierarchical zeolites: Enhanced utilisation of microporous crystals in catalysis by advances in materials design

    DEFF Research Database (Denmark)

    Perez-Ramirez, Javier; Christensen, Claus H.; Egeblad, Kresten

    2008-01-01

    in these materials often imposes intracrystalline diffusion limitations, rendering low utilisation of the zeolite active volume in catalysed reactions. This critical review examines recent advances in the rapidly evolving area of zeolites with improved accessibility and molecular transport. Strategies to enhance...... the properties of the resulting materials and the catalytic function. We particularly dwell on the exciting field of hierarchical zeolites, which couple in a single material the catalytic power of micropores and the facilitated access and improved transport consequence of a complementary mesopore network...

  14. Integration of Magneto-Optical Materials for Novel Optical Devices & Magnetophotonic Crystals Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This work proposes to capitalize on our Phase I success in monolithically integrating magneto-optic and magnetic materials with semiconductor platforms in order to...

  15. Plasmon-Enhanced Photonic Crystal Negative Index Materials for Superlensing Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Negative index materials (NIMs) offer tremendous potential for the formation of highly compact as well as large-area deployable thin-film optical components. Omega...

  16. Properties of defect mode and optical enhancement of 1D photonic crystals with a defect layer of negative refractive index material

    Institute of Scientific and Technical Information of China (English)

    CHEN Xian-feng; SHEN Xiao-ming; JIANG Mei-ping; SHI Du-fang

    2005-01-01

    The band gap properties of one-dimensional photonic crystals with a defect layer of negative refractive index materials are studied.The defect mode width is bigger than that of conventional one-dimensional photonic crystals with a defect layer of positive refractive index materials.The defect mode of the former is different from that of the latter,shifts towards the direction of high frequency (short wavelength),and has a bigger shifting velocity.Furthermore the effects on the transmission properties of the former photonic crystals caused by change in the position of the defect layer of negative refractive index are investigated.Finally the optical enhancement of the former photonic crystals is also investigated.

  17. 46 CFR 7.70 - Folly Island, SC to Hilton Head Island, SC.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Folly Island, SC to Hilton Head Island, SC. 7.70 Section... BOUNDARY LINES Atlantic Coast § 7.70 Folly Island, SC to Hilton Head Island, SC. (a) A line drawn from the southernmost extremity of Folly Island to latitude 32°35′ N. longitude 79°58.2′ W. (Stono Inlet Lighted...

  18. Thermal load leveling during silicon crystal growth from a melt using anisotropic materials

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Frederick M.; Helenbrook, Brian T.

    2016-10-11

    An apparatus for growing a silicon crystal substrate comprising a heat source, an anisotropic thermal load leveling component, a crucible, and a cold plate component is disclosed. The anisotropic thermal load leveling component possesses a high thermal conductivity and may be positioned atop the heat source to be operative to even-out temperature and heat flux variations emanating from the heat source. The crucible may be operative to contain molten silicon in which the top surface of the molten silicon may be defined as a growth interface. The crucible may be substantially surrounded by the anisotropic thermal load leveling component. The cold plate component may be positioned above the crucible to be operative with the anisotropic thermal load leveling component and heat source to maintain a uniform heat flux at the growth surface of the molten silicon.

  19. Nanoporous films for epitaxial growth of single crystal semiconductor materials : final LDRD report.

    Energy Technology Data Exchange (ETDEWEB)

    Rowen, Adam M.; Koleske, Daniel David; Fan, Hongyou; Brinker, C. Jeffrey; Burckel, David Bruce; Williams, John Dalton; Arrington, Christian L.; Steen, William Arthur

    2007-10-01

    This senior council Tier 1 LDRD was focused on exploring the use of porous growth masks as a method for defect reduction during heteroepitaxial crystal growth. Initially our goal was to investigate porous silica as a growth mask, however, we expanded the scope of the research to include several other porous growth masks on various size scales, including mesoporous carbon, photolithographically patterned SU-8 and carbonized SU-8 structures. Use of photolithographically defined growth templates represents a new direction, unique in the extensive literature of patterned epitaxial growth, and presents the possibility of providing a single step growth mask. Additional research included investigation of pore viability via electrochemical deposition into high aspect ratio photoresist. This project was a small footprint research effort which, nonetheless, produced significant progress towards both the stated goal as well as unanticipated research directions.

  20. Quartz Crystal Microbalances for quantitative picosecond laser-material-interaction investigations - Part I: Technical considerations

    Science.gov (United States)

    Gierse, N.; Schildt, T.; Esser, H. G.; Sergienko, G.; Brezinsek, S.; Freisinger, M.; Zhao, D.; Ding, H.; Terra, A.; Samm, U.; Linsmeier, Ch.

    2016-12-01

    In this work the technical suitability of Quartz Crystal Microbalances (QMBs) for in situ, pulse resolved mass removal measurements is demonstrated for picosecond laser ablation of magnetron sputtered coatings. The QMBs show a linear characteristic of the sensitivity for layer thickness of different metals up to several microns. Laser pulse resolved measurements of the mass ablated from the metal layer were performed. About 400 ng of chromium was ablated during the first laser pulse while in subsequent pulses ablation of the QMBs is found to be larger than for deposition, which is explained by the radial sensitivity of the QMBs. Future refinements of the setup and the benefits of the pulse resolved mass loss measurements for laser based methods like LIBS and LIAS are discussed and will be presented in part II currently in preparation.

  1. Structure, phase transition, and controllable thermal expansion behaviors of Sc(2-x)Fe(x)Mo₃O₁₂.

    Science.gov (United States)

    Wu, Meimei; Liu, Xinzhi; Chen, Dongfeng; Huang, Qingzhen; Wu, Hui; Liu, Yuntao

    2014-09-02

    The crystal structures, phase transition, and thermal expansion behaviors of solid solutions of Sc(2-x)Fe(x)Mo3O12 (0 ≤ x ≤ 2) have been examined using X-ray diffraction (XRD), neutron powder diffraction (NPD), and differential scanning calorimetry (DSC). At room temperature, samples crystallize in a single orthorhombic structure for the compositions of x thermal expansion, and the volumetric coefficients of thermal expansion derived from XRD and NPD are 0.28 × 10(-6) °C(-1) (250-800 °C) and 0.65 × 10(-6) °C(-1) (227-427 °C), respectively. NPD results of Sc2Mo3O12 (x = 0) and Sc(1.3)Fe(0.7)Mo3O12 (x = 0.7) indicate that Fe substitution for Sc induces reduction of the mean Sc(Fe)-Mo nonbond distance and the different thermal variations of Sc(Fe)-O5-Mo2 and Sc(Fe)-O3-Mo2 bond angles. The correlation between the displacements of oxygen atoms and the variation of unit cell parameters was investigated in detail for Sc2Mo3O12.

  2. rotor of the SC rotating condenser

    CERN Multimedia

    1974-01-01

    The rotor of the rotating condenser was installed instead of the tuning fork as the modulating element of the radiofrequency system, when the SC accelerator underwent extensive improvements between 1973 to 1975 (see object AC-025). The SC was the first accelerator built at CERN. It operated from August 1957 until it was closed down at the end of 1990.

  3. Radiation Protection Section (SC/SL/RP)

    CERN Multimedia

    2006-01-01

    We should like to inform you that the Radiation Protection Section (SC/SL/RP) located on the Prévessin site has moved from Building 865 (ground floor) to new premises in Wing A of Building 892 (second floor). Telephone numbers remain the same. SC/SL/RP section

  4. Design, crystal growth, and physical properties of low-temperature thermoelectric materials

    Science.gov (United States)

    Fuccillo, Michael K.

    Thermoelectric materials serve as the foundation for two important modern technologies, namely 1) solid-state cooling, which enables small-area refrigeration without vibrations or moving parts, and 2) thermoelectric power generation, which has important implications for waste heat recovery and improved sources of alternative energy. Although the overall field of thermoelectrics research has been active for decades, and several consumer and industrial products have already been commercialized, the design and synthesis of new thermoelectrics that outperform long-standing state of the art materials has proven extremely challenging. This is particularly true for low-temperature refrigeration applications, which is the focus of this work; however, scientific advances in this area generally support power generation as well. In order to achieve more efficient materials for virtually all thermoelectric applications, improved materials design principles must be developed and synthetic procedures must be better understood. We aim to contribute to these goals by studying two classes of materials, namely 1) the tetradymites Bi2TeSe 2 and Bi2Te2Se, which are close relatives of state of the art thermoelectric cooling materials, and 2) Kondo insulating (-like) FeSb2 and FeSi, which possess anomalously enhanced low-temperature thermoelectric properties that arise from exotic electronic and magnetic properties. The organization of this dissertation is as follows: Chapter 1 is a brief perspective on solid-state chemistry. Chapter 2 presents experimental methods for synthesizing and characterizing thermoelectric materials. In Chapter 3, two original research projects are discussed: first, work on the tetradymite Bi2TeSe2 doped with Sb to achieve an n- to p-type transition, and second, the tetradymite Bi2Te2Se with chemical defects through two different methods. Chapter 4 gives the magnetic and transport properties of FeSb 2--RuSb2 alloys, a family of compounds exemplifying what we

  5. Report of AAPM Therapy Physics Committee Task Group 74: in-air output ratio, Sc, for megavoltage photon beams.

    Science.gov (United States)

    Zhu, Timothy C; Ahnesjö, Anders; Lam, Kwok Leung; Li, X Allen; Ma, Chang-Ming Charlie; Palta, Jatinder R; Sharpe, Michael B; Thomadsen, Bruce; Tailor, Ramesh C

    2009-11-01

    The concept of in-air output ratio (Sc) was introduced to characterize how the incident photon fluence per monitor unit (or unit time for a Co-60 unit) varies with collimator settings. However, there has been much confusion regarding the measurement technique to be used that has prevented the accurate and consistent determination of Sc. The main thrust of the report is to devise a theoretical and measurement formalism that ensures interinstitutional consistency of Sc. The in-air output ratio, Sc, is defined as the ratio of primary collision water kerma in free-space, Kp, per monitor unit between an arbitrary collimator setting and the reference collimator setting at the same location. Miniphantoms with sufficient lateral and longitudinal thicknesses to eliminate electron contamination and maintain transient electron equilibrium are recommended for the measurement of Sc. The authors present a correction formalism to extrapolate the correct Sc from the measured values using high-Z miniphantom. Miniphantoms made of high-Z material are used to measure Sc for small fields (e.g., IMRT or stereotactic radiosurgery). This report presents a review of the components of Sc, including headscatter, source-obscuring, and monitor-backscattering effects. A review of calculation methods (Monte Carlo and empirical) used to calculate Sc for arbitrary shaped fields is presented. The authors discussed the use of Sc in photon dose calculation algorithms, in particular, monitor unit calculation. Finally, a summary of Sc data (from RPC and other institutions) is included for QA purposes.

  6. Crystal growth and physical property of Bi-Sb-Te-Se topological insulator and CuxBi2Se3 topological superconductor materials

    Science.gov (United States)

    Gu, Genda; Yang, Alina; Schneeloch, John; Xu, Zhijun; Tranquada, John; Zhoa, J. G.; Pan, Z. H.; Yang, H. B.; Si, W. D.; Valla, T.

    2012-02-01

    The discovery of 3D topological insulator and topological superconductor materials opens up a new research field in the condensed matter physics. In order to exploit the novel surface properties of these topological insulators, it is crucial to achieve a bulk-insulating state in these topological insulator crystals. Unfortunately, all available topological insulator crystals are not bulk-insulating. We have grown a number of Bi-Se, Bi-Te, Sb-Te-Se, Bi-Sb-Se, Bi-Sb-Te-Se and Bi-Sb-Te-Se-S topological insulator single crystals by using 5N and 6N pure elements. We have measured the physical properties on these single crystals. We have studied the effect of growth condition and impurity on the bulk electrical conductivity of these single crystals. We try to answer two questions if it is possible to grow the bulk-insulating topological insulator single crystals and which maximum resistivity of these topological insulator single crystals we can grow. We have also grown a number of CuxBi2Se3 topological superconductor single crystals.

  7. 2D and 3D photonic crystal materials for photocatalysis and electrochemical energy storage and conversion.

    Science.gov (United States)

    Collins, Gillian; Armstrong, Eileen; McNulty, David; O'Hanlon, Sally; Geaney, Hugh; O'Dwyer, Colm

    2016-01-01

    This perspective reviews recent advances in inverse opal structures, how they have been developed, studied and applied as catalysts, catalyst support materials, as electrode materials for batteries, water splitting applications, solar-to-fuel conversion and electrochromics, and finally as photonic photocatalysts and photoelectrocatalysts. Throughout, we detail some of the salient optical characteristics that underpin recent results and form the basis for light-matter interactions that span electrochemical energy conversion systems as well as photocatalytic systems. Strategies for using 2D as well as 3D structures, ordered macroporous materials such as inverse opals are summarized and recent work on plasmonic-photonic coupling in metal nanoparticle-infiltrated wide band gap inverse opals for enhanced photoelectrochemistry are provided.

  8. High quality 2D crystals made by anodic bonding: a general technique for layered materials.

    Science.gov (United States)

    Gacem, Karim; Boukhicha, Mohamed; Chen, Zhesheng; Shukla, Abhay

    2012-12-21

    Anodic bonding of nanolayers is an easy technique based on a simple apparatus, which has already proven successful in application in the fabrication of high quality graphene. Here we demonstrate its extension to the fabrication of high quality nanolayers from several layered materials. The strengths of this technique are its high throughput rate and ease of application. All fabrication parameters are controllable and need to be determined carefully. We report optimal parameters found for nine layered materials. In general, using optimal parameters results in high quality 2D layers, in most cases much larger than those obtained by 'Scotch tape' microcleavage, with higher yields and which are easily transferable to other substrates. Moreover the samples obtained are clean and the good optical contrast of these layers on the glass substrate makes their identification very easy. This is thus the technique of choice for making nanolayers in the laboratory from any layered material.

  9. High quality 2D crystals made by anodic bonding: a general technique for layered materials

    Science.gov (United States)

    Gacem, Karim; Boukhicha, Mohamed; Chen, Zhesheng; Shukla, Abhay

    2012-12-01

    Anodic bonding of nanolayers is an easy technique based on a simple apparatus, which has already proven successful in application in the fabrication of high quality graphene. Here we demonstrate its extension to the fabrication of high quality nanolayers from several layered materials. The strengths of this technique are its high throughput rate and ease of application. All fabrication parameters are controllable and need to be determined carefully. We report optimal parameters found for nine layered materials. In general, using optimal parameters results in high quality 2D layers, in most cases much larger than those obtained by ‘Scotch tape’ microcleavage, with higher yields and which are easily transferable to other substrates. Moreover the samples obtained are clean and the good optical contrast of these layers on the glass substrate makes their identification very easy. This is thus the technique of choice for making nanolayers in the laboratory from any layered material.

  10. Crystal Data

    Science.gov (United States)

    SRD 3 NIST Crystal Data (PC database for purchase)   NIST Crystal Data contains chemical, physical, and crystallographic information useful to characterize more than 237,671 inorganic and organic crystalline materials. The data include the standard cell parameters, cell volume, space group number and symbol, calculated density, chemical formula, chemical name, and classification by chemical type.

  11. Single-crystal lead magnesium niobate-lead titanate (PMN/PT) as a broadband high power transduction material.

    Science.gov (United States)

    Moffett, Mark B; Robinson, Harold C; Powers, James M; Baird, P David

    2007-05-01

    Two experimental underwater acoustic projectors, a tonpilz array, and a cylindrical line array, were built with single crystal, lead magnesium niobate/lead titanate, a piezoelectric transduction material possessing a large electromechanical coupling factor (k33 = 0.9). The mechanical quality factor, Q(m), and the effective coupling factor, k(eff), determine the frequency band over which high power can be transmitted; k(eff) cannot be greater than the piezoelectric material value, and so a high material coupling factor is a requisite for broadband operation. Stansfield's bandwidth criteria are used to calculate the optimum Q(m) value, Q(opt) approximately 1.2 (1-k(eff)2 1/2/k(eff). The results for the tonpilz projector exhibited k(eff) = 0.730, Q(m) = 1.17 (very near optimal), and a fractional bandwidth of 0.93. For the cylindrical transducer array, k(eff) = 0.867, Q(m) = 0.91 (larger than the optimum value, 0.7), and the bandwidth was 1.16. Although the measured bandwidths were less than optimal, they were accurately predicted by the theory, despite the highly simplified nature of the Van Dyke equivalent circuit, on which the theory is based.

  12. Rheological Modeling with Hookean Bead-Spring Cubes (SC, BBC and FCC)

    NARCIS (Netherlands)

    Denneman, A.I.M.; Jongschaap, R.J.J.; Mellema, J.

    1998-01-01

    In this study a general bead-spring model is used for predicting some rheological properties of a cubic bead-spring structure of arbitrary size immersed in a Newtonian solvent. The topology of this bead-spring structure is based upon the well-known cubic crystals (SC, BCC or FCC) and it consists of

  13. Pressure-induced structural transformations in the molybdate Sc-2(MoO4)(3)

    DEFF Research Database (Denmark)

    Paraguassu, W.; Maczka, M.; Filho, A. G. Sonza

    2004-01-01

    . The crystal to amorphous transition is irreversible. Our results point out that the amorphization process in Sc-2(MoO4)(3) may be due to a kinetic hindrance of a phase transition rather than due to chemical decomposition effects as have been proposed to occur for some molybdates and tungstates....

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

    Science.gov (United States)

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

    2007-03-19

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

  15. Ultra-narrow bandwidth optical filters consisting of one-dimensional photonic crystals with anomalous dispersion materials

    Institute of Scientific and Technical Information of China (English)

    Liu Jiang-Tao; Zhou Yun-Song; Wang Fu-He; Gu Ben-Yuan

    2005-01-01

    We present a new type of optical filter with an ultra-narrow bandwidth and a wide field-of-view (FOV). This kind of optical filter consists of one-dimensional photonic crystal (PC) incorporating an anomalous-dispersion-material (ADM) with, for instance, an anomalous dispersion of 6P3/2 ← 6S1/2 hyperfine structure transition of a caesium atom.The transmission spectra of optical filters are calculated by using the transfer-matrix method. The simulation results show that the designed optical filter has a bandwidth narrower than 0.33GHz and a wide FOV of ±30° as well. The response of transmission spectrum to an external magnetic field is also investigated.

  16. Technological process and optimum design of organic materials vacuum pyrolysis and indium chlorinated separation from waste liquid crystal display panels.

    Science.gov (United States)

    Ma, En; Xu, Zhenming

    2013-12-15

    In this study, a technology process including vacuum pyrolysis and vacuum chlorinated separation was proposed to convert waste liquid crystal display (LCD) panels into useful resources using self-design apparatuses. The suitable pyrolysis temperature and pressure are determined as 300°C and 50 Pa at first. The organic parts of the panels were converted to oil (79.10 wt%) and gas (2.93 wt%). Then the technology of separating indium was optimized by central composite design (CCD) under response surface methodology (RSM). The results indicated the indium recovery ratio was 99.97% when the particle size is less than 0.16 mm, the weight percentage of NH4Cl to glass powder is 50 wt% and temperature is 450°C. The research results show that the organic materials, indium and glass of LCD panel can be recovered during the recovery process efficiently and eco-friendly.

  17. Eco-friendly p-type Cu2SnS3 thermoelectric material: crystal structure and transport properties

    Science.gov (United States)

    Shen, Yawei; Li, Chao; Huang, Rong; Tian, Ruoming; Ye, Yang; Pan, Lin; Koumoto, Kunihito; Zhang, Ruizhi; Wan, Chunlei; Wang, Yifeng

    2016-01-01

    As a new eco-friendly thermoelectric material, copper tin sulfide (Cu2SnS3) ceramics were experimentally studied by Zn-doping. Excellent electrical transport properties were obtained by virtue of 3-dimensionally conductive network for holes, which are less affected by the coexistence of cubic and tetragonal phases that formed upon Zn subsitition for Sn; a highest power factors ~0.84 mW m−1 K−2 at 723 K was achieved in the 20% doped sample. Moreover, an ultralow lattice thermal conductivity close to theoretical minimum was observed in these samples, which could be related to the disordering of atoms in the coexisting cubic and tetragonal phases and the interfaces. Thanks to the phonon-glass-electron-crystal features, a maximum ZT ~ 0.58 was obtained at 723 K, which stands among the tops for sulfide thermoelectrics at the same temperature. PMID:27666524

  18. Statistical studies on the light output and energy resolution of small LSO single crystals with different surface treatments combined with various reflector materials

    CERN Document Server

    Heinrichs, U; Bussmann, N; Engels, R; Kemmerling, G; Weber, S; Ziemons, K

    2002-01-01

    The optimization of light output and energy resolution of scintillators is of special interest for the development of high resolution and high sensitivity PET. The aim of this work is to obtain statistically reliable results concerning optimal surface treatment of scintillation crystals and the selection of reflector material. For this purpose, raw, mechanically polished and etched LSO crystals (size 2x2x10 mm sup 3) were combined with various reflector materials (Teflon tape, Teflon matrix, BaSO sub 4) and exposed to a sup 2 sup 2 Na source. In order to ensure the statistical reliability of the results, groups of 10 LSO crystals each were measured for all combinations of surface treatment and reflector material. Using no reflector material the light output increased up to 551+-35% by mechanical polishing the surface compared to 100+-5% for raw crystals. Etching the surface increased the light output to 441+-29%. The untreated crystals had an energy resolution of 24.6+-4.0%. By mechanical polishing the surfac...

  19. Material purification, crystal growth, and spectroscopy of Tm-doped KPb2Cl5 and KPb2Br5 for 2 μm photonic applications

    Science.gov (United States)

    Brown, E.; Kumi-Barimah, E.; Hömmerich, U.; Bluiett, A. G.; Trivedi, S. B.

    2014-05-01

    Results of the material purification, crystal growth, and optical characterization of Tm-doped KPb2Cl5 (KPC) and KPb2Br5 (KPB) for 2 μm photonic applications are presented. Undoped KPC and KPB were synthesized from ultra dry starting materials and purified through multi-pass translation in a zone-refinement system. 1 wt% of ultra-dry Tm-halides (TmCl3 or TmBr3) were added to the purified host materials and molten under bubbling of HCl or HBr gas, respectively. Tm: KPC and Tm: KPB crystals were subsequently grown using the Bridgman technique. The good optical quality of the resulting crystals was indicated by infrared transmissions as high as 70-75%. Under optical pumping, both crystals exhibited broad infrared emission bands centered at 1.82 μm with nearly exponential decay times ranging from 2-3 ms. Judd-Ofelt intensity parameters were calculated to determine the radiative lifetimes of the 3F4→3H6 Tm3+ transition. The optical absorption and emission cross-sections of Tm: KPC and Tm: KPB were determined using the McCumber theory. The investigated crystals were also evaluated as potential solid-state materials for optical cooling applications.

  20. Flat band degeneracy and near-zero refractive index materials in acoustic crystals

    Directory of Open Access Journals (Sweden)

    Shiqiao Wu

    2016-01-01

    Full Text Available A Dirac-like cone is formed by utilizing the flat bands associated with localized modes in an acoustic crystal (AC composed of a square array of core-shell-structure cylinders in a water host. Although the triply-degeneracy seems to arise from two almost-overlapping flat bands touching another curved band, the enlarged view of the band structure around the degenerate point reveals that there are actually two linear bands intersecting each other at the Brillouin zone center, with another flat band passing through the same crossing point. The linearity of dispersion relations is achieved by tuning the geometrical parameters of the cylindrical scatterers. A perturbation method is used to not only accurately predict the linear slopes of the dispersions, but also confirm the linearity of the bands from first principles. An effective medium theory based on coherent potential approximation is developed, and it shows that a slab made of the AC carries a near-zero refractive index around the Dirac-like point. Full-wave simulations are performed to unambiguously demonstrate the wave manipulating properties of the AC structures such as perfect transmission, unidirectional transmission and wave front shaping.

  1. Formation Processes of Nanocomposite Strengthening Particles in Rapidly Quenched Al-Sc-Zr Alloys

    Directory of Open Access Journals (Sweden)

    A.V. Kotko

    2012-03-01

    Full Text Available Decomposition processes of supersaturated solid solution of aluminium alloys alloyed with Sc and Zr have been studied in the work. The binary hypereutectic Al-Sc alloys, hyperperitectic Al-Zr alloys and ternary Al-Sc-Zr alloys were chosen. Alloys were obtained by the melt-spinning. Melts were quenched from temperatures of Т = 1000 C and Т = 1400 ºC. The study of the structure of rapidly solidifyed binary Al alloys alloyed with Sc and Zr showed that the crystallization of anomalously supersaturated solid solution (Tquen. = 1400 ºC or the crystallization with the formation of "fan" structure (Tquen. = 1000 ºC are possible depending on the quenching temperature of the melt. The decomposition of anomalously supersaturated solid solution is continuous, with the precipitation of nano-sized spherical Al3X (X-Sc, Zr particles of L12-ordered phase which is isomorphous to matrix. It was found that the loss of thermal stability of Al-Sc alloys is due to the loss of coherence of the strengthening Al3Sc phase. In Al-Zr alloys the loss of strength is due to the formation of a stable tetragonal DO23-ordered A13Zr phase. After co-alloying of Al by Sc and Zr a bimodal grained structure was observed for the hypereutectic ternary alloy (Tquen. = 400ºC. Nano-sized grains of 50-60 nm were present on the boundaries of 1-2 µm large-sized grains. TEM shows the formation of nanocomposite Al3Zr/Al3Sc particles. The formation of Al3Zr shell changes the nature of the interfacial fit of the particle with the matrix and slows down the decomposition during the coalescence. Ternary Al-Sc-Zr alloys have significantly higher thermal stability during aging as compared to binary Al-Sc and Al-Zr alloys. Decomposition processes of supersaturated solid solution of aluminium alloys alloyed with Sc and Zr have been studied in the work. The binary hypereutectic Al-Sc alloys, hyperperitectic Al-Zr alloys and ternary Al-Sc-Zr alloys were chosen. Alloys were

  2. 2D Crystal Semiconductors New Materials for GHz-THz Devices

    Science.gov (United States)

    2015-10-02

    chemical catalysis (MoS2, graphite), lithium–ion batteries (lithium cobaltate and layered carbon), lubricants (MoS2), neutron moderation in nuclear ... reactors (graphite), and thermally and mechani- cally refractory crucibles used in much of electronic material and device processing (BN and graphite). The...SF298 Form Please attach your SF298 form. A blank SF298 can be found here. Please do not password protect or secure the PDF The maximum file size for

  3. A Single-Material Logical Junction Based on 2D Crystal PdS2.

    Science.gov (United States)

    Ghorbani-Asl, Mahdi; Kuc, Agnieszka; Miró, Pere; Heine, Thomas

    2016-02-01

    A single-material logical junction with negligible contact resistance is designed by exploiting quantum-confinement effects in 1T PdS2 . The metallic bilayer serves as electrodes for the semiconducting channel monolayer, avoiding contact resistance. Heat dissipation is then governed by tunnel loss, which becomes negligible at channel lengths larger than 2.45 nm. This value marks the integration limit for a conventional 2D transistor.

  4. Sulfated dextrans enhance in vitro amplification of bovine spongiform encephalopathy PrP(Sc and enable ultrasensitive detection of bovine PrP(Sc.

    Directory of Open Access Journals (Sweden)

    Yuichi Murayama

    Full Text Available BACKGROUND: Prions, infectious agents associated with prion diseases such as Creutzfeldt-Jakob disease in humans, bovine spongiform encephalopathy (BSE in cattle, and scrapie in sheep and goats, are primarily comprised of PrP(Sc, a protease-resistant misfolded isoform of the cellular prion protein PrP(C. Protein misfolding cyclic amplification (PMCA is a highly sensitive technique used to detect minute amounts of scrapie PrP(Sc. However, the current PMCA technique has been unsuccessful in achieving good amplification in cattle. The detailed distribution of PrP(Sc in BSE-affected cattle therefore remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: We report here that PrP(Sc derived from BSE-affected cattle can be amplified ultra-efficiently by PMCA in the presence of sulfated dextran compounds. This method is capable of amplifying very small amounts of PrP(Sc from the saliva, palatine tonsils, lymph nodes, ileocecal region, and muscular tissues of BSE-affected cattle. Individual differences in the distribution of PrP(Sc in spleen and cerebrospinal fluid samples were observed in terminal-stage animals. However, the presence of PrP(Sc in blood was not substantiated in the BSE-affected cattle examined. CONCLUSIONS/SIGNIFICANCE: The distribution of PrP(Sc is not restricted to the nervous system and can spread to peripheral tissues in the terminal disease stage. The finding that PrP(Sc could be amplified in the saliva of an asymptomatic animal suggests a potential usefulness of this technique for BSE diagnosis. This highly sensitive method also has other practical applications, including safety evaluation or safety assurance of products and byproducts manufactured from bovine source materials.

  5. Crystal structure, optical and thermal studies of a new organic nonlinear optical material: L-Histidinium maleate 1.5-hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Gonsago, C. Alosious [Department of Physics, A. J. College of Engineering, Chennai 603103 (India); Albert, Helen Merina [Department of Physics, Sathyabama University, Chennai 600119 (India); Karthikeyan, J. [Department of Chemistry, Sathyabama University, Chennai 600119 (India); Sagayaraj, P. [Department of Physics, Loyola College, Chennai 600034 (India); Pragasam, A. Joseph Arul, E-mail: drjosephsu@gmail.com [Department of Physics, Sathyabama University, Chennai 600119 (India)

    2012-07-15

    Highlights: ► L-Histidinium maleate 1.5-hydrate, a new organic crystal has been grown for the first time. ► The crystal structure is reported for the first time (CCDC 845975). ► The crystal belongs to monoclinic system with space group P2{sub 1}, Z = 4, a = 11.4656(7) Å, b = 8.0530(5) Å, c = 14.9705(9) Å and β = 101.657(2)°. ► The optical absorption study substantiates the complete transparency of the crystal. ► Kurtz powder SHG test confirms the nonlinear property of the crystal. -- Abstract: A new organic nonlinear optical material L-histidinium maleate 1.5-hydrate (LHM) with the molecular formula C{sub 10}H{sub 16}N{sub 3}O{sub 7.5} has been successfully synthesized from aqueous solution by slow solvent evaporation method. The structural characterization of the grown crystal was carried out by single crystal X-ray diffraction at 293(2) K. In the crystal, molecules are linked through inter and intramolecular N-H⋯O and O-H⋯O hydrogen bonds, generate edge fused ring motif. The hydrogen bonded motifs are linked to each other to form a three dimensional network. The FT-IR spectroscopy was used to identify the functional groups of the synthesized compound. The optical behavior of the grown crystal was examined by UV–visible spectral analysis, which shows that the optical absorption is almost negligible in the wavelength range 280–1300 nm. The nonlinear optical property was confirmed by the powder technique of Kurtz and Perry. The thermal behavior of the grown crystal was analyzed by thermogravimetric analysis.

  6. Transmission properties of a Fibonacci quasi-crystals containing single-negative materials and their usage as multi-channel filters

    Science.gov (United States)

    Charkhesht, Ali; Pashaei Adl, Hamid; Roshan Entezar, Samad

    2014-03-01

    One of the interesting phenomena appearing in Fibonacci quasi-crystals is wave localization, so that the field becomes spatially confined in some suitable regions, or delocalized in some other parts. Many theoretical works have been written on this interesting subject. The periodic Fibonacci structure properties lead to a transmission spectrum that exhibits some band gap, and it is possible to control these band gaps by the generation number of this structures. All these properties make Fibonacci quasi-crystals materials very attractive from an optical point of view. Accordingly, the transmission properties of Fibonacci quasi-crystals containing single-negative materials are investigated with the transfer matrix method. It is shown that the periodic structures created by repeating the Fibonacci quasi-crystal generations, have some omnidirectional band gaps at the single-negative frequency region. Moreover, it is shown these band gaps depends on the number of Fibonacci photonic crystal unit cell. In other words, when generation number of Fibonacci photonic crystal unit cell increases, some sub band gaps appears within this omnidirectional band gap. In this work by using Fibonacci quasi-periodic structures we demonstrate that by increasing Generation Number of Unit cell, some omnidirectional sub-gaps will appear which can be used as a multichannel filter.

  7. Linearized augmented-plane-wave method for quasi-unidimensional systems: Carbyne and nanotube (Sc@C{sub 20})

    Energy Technology Data Exchange (ETDEWEB)

    D`yachkov, P.N. [Kurnakov Institute of General and Inorganic Chemistry, Moscow (Russian Federation); Nikolaev, A.V. [Institute of Physcial Chemistry, Moscow (Russian Federation)

    1995-10-01

    The advent of carbon nanotubes, which are graphite layers convoluted in cylinders several nanometers in diameter and several micrometers in length, as well as the experiments on implanting metal atoms in such tubes open the way to producing nanoconductors and other materials with unique properties. For theorists, the basic challenge is interpreting and predicting the structure and properties of these systems. The linearized augmented-plane-wave method (LAPW) is one of the most accurate methods in the theory of the electronic structure of solids. A generalization of this method for quasi-two-dimensional systems, surface electronic states, and layered crystals is known. The LAPW theory for quasi-unidimensional systems, which exhibit translational symmetry in one direction, has been absent thus far. In this paper, the authors suggest a version of such a theory and use this method to calculate the electronic structure of carbyne (a linear chain of carbon atoms) and carbon nanotube with implanted Sc atoms.

  8. SC-FDMA for mobile communications

    CERN Document Server

    Abd El-Samie, Fathi E

    2013-01-01

    SC-FDMA for Mobile Communications examines Single-Carrier Frequency Division Multiple Access (SC-FDMA). Explaining this rapidly evolving system for mobile communications, it describes its advantages and limitations and outlines possible solutions for addressing its current limitations. The book explores the emerging trend of cooperative communication with SC-FDMA and how it can improve the physical layer security. It considers the design of distributed coding schemes and protocols for wireless relay networks where users cooperate to send their data to the destination. Supplying you with the re

  9. VUV spectroscopy of nominally pure and rare-earth ions doped LiCaAIF6 single crystals as promising materials for 157 nm photolithography

    Science.gov (United States)

    Cefalas, Alkiviadis C.; Sarantopoulou, Evangelia; Kollia, Z.; Abdulsabirov, R. Y.; Korableva, S. L.; Naumov, A. K.; Semashko, V. V.; Kobe, S.; McGuiness, P. J.

    2002-07-01

    Recently it was found that birefringence is induced in CaF2 crystals when they are illuminated with laser light at 157 nm. Taking into consideration that CaF2 is the only optical material used in 157 nm photolithography today, the possibility to use new wide band gap fluoride crystals as optical elements for 157 nm photolithography, even those of non-cubic symmetry, should be considered. Additionally fluoride dielectric crystals with wide band gaps doped with trivalent rare-earth (RE) ions can be used as passive or active optical elements int eh VUV. For doped crystals, applications depend on the structure of the energy level pattern of the 4fn-15d electronic configuration and RE ion concentration. In this work we are exploiting the use of wide band gap fluoride dielectric crystals doped with RE ions. The laser induced fluorescence spectrum at 157 nm, and the absorption spectra of the LiCaAlF6 crystals, pure and doped with RE ions, were investigated in the VUV region of the spectrum. A new m4tehod for monitoring RE concentration in wide band gap fluoride crystals, that is based on vibrating sample magnetometer measurement is presented as well.

  10. Sm-doped CsBr crystal as a new radio-photoluminescence (RPL) material

    Institute of Scientific and Technical Information of China (English)

    Go Okada; Yutaka Fujimoto; Hironori Tanaka; Safa Kasap; Takayuki Yanagida

    2016-01-01

    Radio-photoluminescence (RPL) is a phenomenon seen in luminescent materials in which the appearance of new photolu-minescence (PL) emission is induced by an incident ionizing radiation such as X-rays;and the signal is stable even after the irradia-tion and during the PL measurement. Since the induced PL intensity is proportional to the irradiation dose, the RPL can be used in ra-diation measurements. The distinct advantage of RPL over the conventional thermally-or photo-stimulated luminescence (abbrevi-ated as TSL or PSL) dosimeters is the stability of response signal. With an RPL detector, it allows us to readout the signal multiple time without signal fading. In this work, we discovered that CsBr:Sm showed an RPL phenomenon by X-ray irradiation, and we characterized this new material as an RPL detector. While the sample showed PL emissions mainly in the visible range, after an X-ray irradiation additional emissions could be observed in the red to near-infrared range around 650–850 nm and 900–1000 nm and longer. The RPL response was fairly stable overall, but very interestingly the 650–850 nm signal slightly increased while the 900–1000 nm decreased during PL readout. The dynamic range was confirmed over 1–104 mGy with linear response.

  11. Synthesis, crystal growth and characterization of bioactive material: 2- Amino-1H-benzimidazolium pyridine-3-carboxylate single crystal- a proton transfer molecular complex

    Science.gov (United States)

    Fathima, K. Saiadali; Kavitha, P.; Anitha, K.

    2017-09-01

    The 1:1 molecular adducts 2- Amino-1H-benzimidazolium pyridine-3-carboxylate (2ABPC) was synthesized and grown as single crystal where 2-aminobenzimidazole (ABI) acts as a donor and nicotinic acid (NA) acts as an acceptor. The presence of proton and carbon were predicted using 1H and 13C NMR spectral analysis. The molecular structure of the crystal was elucidated by subjecting the grown crystals to the single crystal x-ray diffraction analysis and was refined by full matrix least-squares method to R = 0.038 for 2469 reflections. The vibrational modes of functional group have been studied using FTIR and Raman spectroscopic analysis. The UV-Vis spectrum exhibited a visible band at 246 nm for 2ABPC due to the nicotinate anion of the molecule. Further, the antimicrobial activity of 2ABPC complex against B. subtilis, klebsiella pneumonia, Pseudomonas eruginos and E. coli pathogens was investigated. Minimum Inhibitory Concentration (MIC) for this crystal was obtained using UV spectrometer against MRSA pathogen. It was found that the benzimidazole with aminogroup at position 2 increases the general antimicrobial activities of 2ABPC crystal.

  12. Research progress of cholesteric liquid crystals with broadband reflection characteristics in application of intelligent optical modulation materials

    Science.gov (United States)

    Zhang, Lan-Ying; Gao, Yan-Zi; Song, Ping; Wu, Xiao-Juan; Yuan, Xiao; He, Bao-Feng; Chen, Xing-Wu; Hu, Wang; Guo, Ren-Wei; Ding, Hang-Jun; Xiao, Jiu-Mei; Yang, Huai

    2016-09-01

    Cholesteric liquid crystals (CLCs) have recently sparked an enormous amount of interest in the development of soft matter materials due to their unique ability to self-organize into a helical supra-molecular architecture and their excellent selective reflection of light based on the Bragg relationship. Nowadays, by the virtue of building the self-organized nanostructures with pitch gradient or non-uniform pitch distribution, extensive work has already been performed to obtain CLC films with a broad reflection band. Based on authors’ many years’ research experience, this critical review systematically summarizes the physical and optical background of the CLCs with broadband reflection characteristics, methods to obtain broadband reflection of CLCs, as well as the application in the field of intelligent optical modulation materials. Combined with the research status and the advantages in the field, the important basic and applied scientific problems in the research direction are also introduced. Project supported by the National Natural Science Foundation of China (Grant Nos. 51573006, 51573003, 51203003, 51303008, 51302006, 51402006, 51272026, and 51273022), the Major Project of Beijing Science and Technology Program, China (Grant Nos. Z151100003315023 and Z141100003814011), and the Fok Ying Tung Education Foundation, China (Grant No. 142009).

  13. Emergence of Zeolite Analogs and other Microporous Crystals in an Atomic Lattice Model of Silica and Related Materials.

    Science.gov (United States)

    Jin, Lin; Auerbach, Scott M; Monson, Peter A

    2012-03-15

    The potential of tailored nanopores to transform technologies such as drug delivery, biofuel production, and optical-electronic devices depends on fundamental knowledge of the self-assembly of ordered nanoporous solids. Atomic-level geometries of critical nuclei that lead to such solids have remained hidden in the nanoscale blind spot between local (5 nm) probes of structure. Heroic efforts at molecular simulation of nanopore formation have provided massive libraries of hypothetical structures; (1-5) however, to date no statistical simulation has generated a crystallization pathway from random initial condition to ordered nanoporous solid, until now. In this work, we show that a recently developed atomic lattice model of silica and related materials can form ordered nanoporous solids with a rich variety of structures including known chalcogenides, zeolite analogs, and layered materials. We find that whereas canonical Monte Carlo simulations of the model consistently produce the amorphous solids studied in our previous work, parallel tempering Monte Carlo gives rise to ordered nanoporous solids. The utility of parallel tempering highlights the existence of barriers between amorphous and crystalline phases of our model. Moreover, the self-assembly or nanoporous crystalline phases in the model open the door to detailed understanding of nanopore nucleation.

  14. Light propagation in two-dimensional photonic crystals based on uniaxial polar materials: results on polaritonic spectrum

    Science.gov (United States)

    Gómez-Urrea, H. A.; Duque, C. A.; Pérez-Quintana, I. V.; Mora-Ramos, M. E.

    2017-03-01

    The dispersion relations of two-dimensional photonic crystals made of uniaxial polaritonic cylinders arranged in triangular lattice are calculated. The particular case of the transverse magnetic polarization is taken into account. Three different uniaxial materials showing transverse phonon-polariton excitations are considered: aluminum nitride, gallium nitride, and indium nitride. The study is carried out by means of the finite-difference time-domain technique for the solution of Maxwell equations, together with the method of the auxiliary differential equation. It is shown that changing the filling fraction can result in the modification of both the photonic and polaritonic bandgaps in the optical dispersion relations. Wider gaps appear for smaller filling fraction values, whereas a larger number of photonic bandgaps will occur within the frequency range considered when a larger filling fraction is used. The effect of including the distinct wurtzite III-V nitride semiconductors as core materials in the cylinders embedded in the air on the photonic properties is discussed as well, highlighting the effect of the dielectric anisotropy on the properties of the polaritonic part of the photonic spectrum.

  15. Bulk Crystal Growth, and High-Resolution X-ray Diffraction Results of LiZnAs Semiconductor Material

    Science.gov (United States)

    Montag, Benjamin W.; Reichenberger, Michael A.; Sunder, Madhana; Ugorowski, Philip B.; Nelson, Kyle A.; Henson, Luke C.; McGregor, Douglas S.

    2017-08-01

    LiZnAs is being explored as a candidate for solid-state neutron detectors. The compact form, solid-state device would have greater efficiency than present day gas-filled 3He and 10BF3 detectors. Devices fabricated from LiZnAs having either natural Li (nominally 7.5% 6Li) or enriched 6Li (usually 95% 6Li) as constituent atoms may provide a material for compact high efficiency neutron detectors. The 6Li( n, t)4He reaction yields a total Q-value of 4.78 MeV, an energy larger than that of the 10B reaction, which can easily be identified above background radiations. LiZnAs material was synthesized by preparing equimolar portions of Li, Zn, and As sealed under vacuum (10-6 Torr) in quartz ampoules lined with boron nitride and subsequently reacted in a compounding furnace (Montag et al. in J Cryst Growth 412:103, 2015). The raw synthesized LiZnAs was purified by a static vacuum sublimation in quartz (Montag et al. in J Cryst Growth 438:99, 2016). Bulk crystalline LiZnAs ingots were grown from the purified material with a high-temperature Bridgman-style growth process described here. One of the largest LiZnAs ingots harvested was 9.6 mm in diameter and 4.2 mm in length. Samples were harvested from the ingot and were characterized for crystallinity using a Bruker AXS Inc. D8 AXS Inc. D2 CRYSO, energy dispersive x-ray diffractometer, and a Bruker AXS Inc. D8 DISCOVER, high-resolution x-ray diffractometer equipped with molybdenum radiation, Gobel mirror, four bounce germanium monochromator and a scintillation detector. The primary beam divergence was determined to be 0.004°, using a single crystal Si standard. The x-ray based characterization revealed that the samples nucleated in the (110) direction and a high-resolution open detector rocking curve recorded on the (220) LiZnAs yielded a full width at half maximum (FWHM) of 0.235°. Sectional pole figures using off-axis reflections of the (211) LiZnAs confirmed in-plane ordering, and also indicated the presence of multiple

  16. Two-gap superconductivity in R2Fe3Si5 (R=Lu, Sc and Sc5Ir4Si10

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Tamegai, Yasuyuki Nakajima, Tsuyoshi Nakagawa, Guoji Li and Hisatomo Harima

    2008-01-01

    Full Text Available R2Fe3Si5 (R= Sc, Y, Lu contains nonmagnetic iron and has a relatively high superconducting transition temperature Tc among iron-containing superconductors. An anomalous temperature dependence of specific heat C(T has been reported for polycrystalline samples down to 1 K. We have grown R2Fe3Si5 single crystals, confirmed the anomalous C(T dependence, and found a second drop in specific heat below 1 K. In Lu2Fe3Si5, we can reproduce C(T below Tc, assuming two distinct energy gaps 2Δ 1/kBTc = 4.4 and 2Δ 2/kBTc = 1.1, with nearly equal weights, indicating that Lu2Fe3Si5 is a two-gap superconductor similar to MgB2. Hall coefficient measurements and band structure calculation also support the multiband contributions to the normal-state properties. The specific heat in the Sc2Fe3Si5 single crystals also shows the two-gap feature. R5Ir4Si10 (R = Sc, rare earth is also a superconductor where competition between superconductivity and the charge-density wave is known for rare earths but not for Sc. We have performed detailed specific heat measurements on Sc5Ir4Si10 single crystals and found that C(T deviates slightly from the behavior expected for weak-coupling superconductors. C(T for these superconductors can also be reproduced well by assuming two superconducting gaps.

  17. Photoemission spectroscopy of single crystal HTSC materials: A Fermi liquid electronic structure

    Energy Technology Data Exchange (ETDEWEB)

    Arko, A.J.; List, R.S.; Bartlett, R.J.; Cheong, S.W.; Olson, C.G.; Yang, A.B.; Liu, R.; Gu, C.; Veal, B.W.; Liu, J.Z.

    1989-01-01

    Photoemission spectra from HTSC materials (primarily 123-type), cleaved and measured at 20K, reveal a rich DOS structure which compares favorably with a calculated band structure, except for a residual 0.5 eV shift which may reflect some correlation effects. Band dispersion is observed throughout the valence bands, with clear evidence for a 0.2 eV wide band dispersing through E/sub F/. The orbital character at E/sub F/ is a mix of Cu-3d and O-2p. There is unambiguous evidence for a large BCS-like gap (2..delta.. greater than or equal to 4kT/sub c/). 25 refs., 5 figs.

  18. Crystal growth of various ruthenates

    Energy Technology Data Exchange (ETDEWEB)

    Kunkemoeller, Stefan; Braden, Markus [II. Physikalisches Institut, Universitaet zu Koeln (Germany); Nugroho, Agung [Institut Teknologi Bandung (Indonesia)

    2013-07-01

    Ruthenates of the Ruddlesdon-Popper series exhibit a variety of interesting phenomena ranging from unconventional superconductivity to orbitally polarized Mott insulators. Unfortunately the crystal growth of most of these ruthenates is extremely difficult partially due to the high evaporation of ruthenium; this strongly limits the research on these fascinating materials. We have started to grow single crystals of layered and perovskite ruthenates by the travelling floating-zone method using a Canon SC1-MDH mirror furnace. For the layered Ca{sub 2-x}Sr{sub x}RuO{sub 4} series we focused first on the range of concentration where recent My-SR experiments reveal spin-density wave ordering to occur at relatively high temperature and with a sizeable ordered moment. Good quality crystals of Ca{sub 1.5}Sr{sub 0.5}RuO{sub 4} can be obtained, when an excess of 15 percent of ruthenium is added to the initial preparation of the rod and when a high growth speed up to 40mm/h is used. Even slight modifications of the growing conditions result in large amounts of (Sr/Ca)RuO{sub 3} and (Sr/Ca){sub 3}Ru{sub 2}O{sub 7} intergrowth phases. First attempts to grow perovskite and double-layered ruthenates are discussed as well.

  19. z206sc_video_observations

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents video observations from cruise Z206SC for the Santa Barbara Channel region and beyond in southern California. The vector data file is...

  20. z107sc_video_observations

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents video observations from cruise Z107SC for the Santa Barbara Channel region and beyond in southern California. The vector data file is...

  1. z206sc_video_observations

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents video observations from cruise Z206SC for the Santa Barbara Channel region and beyond in southern California. The vector data file is...

  2. z107sc_video_observations

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents video observations from cruise Z107SC for the Santa Barbara Channel region and beyond in southern California. The vector data file is...

  3. Bandwidth challenge teams at SC2003 conference

    CERN Multimedia

    2003-01-01

    Results from the fourth annual High-Performance Bandwidth Challenge, held in conjunction with SC2003, the international conference on high-performance computing and networking which occurred last week in Phoenix, AZ (1 page).

  4. Recrystallization of Al-Sc alloys

    Energy Technology Data Exchange (ETDEWEB)

    Drits, M.E.; Toropova, L.S.; Bykov, Yu.G.; Ber, L.B.

    Scandium effect on the temperature range of aluminium recrystallization was investigated. Al-Sc alloys were studied under cold rolled and hot pressed conditions. It is found that the temperature range of Al-Sc alloy recrystallization depends on ScAl/sub 3/ particle dispersion during recrystallization heats. During heating in quenched alloys at 200-300 deg C decomposition occurs which prevents recrystallization, In the alloys with scandium contents less 0.2% decomposition and recrystallization processes pass simultaneously. In quenched alloys with scandium contents over 0.2% and in aged alloys the initiation and subsequent development of recrystallization are determined by the processes of coalescence and solution of ScAl/sub 3/ phase particles.

  5. Investigation on structural, optical, thermal, mechanical and dielectric properties of L-proline cadmium chloride monohydrate single crystals: An efficient NLO material

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Preeti; Hasmuddin, Mohd [Crystal Growth and XRD Lab, Department of Physics, Jamia Millia Islamia, New Delhi 110 025 (India); Shakir, Mohd [Crystal Growth and XRD Lab, Department of Physics, Jamia Millia Islamia, New Delhi 110 025 (India); CSIR-National Physical Laboratory, New Delhi 110 012 (India); Department of Physics, ARSD College, University of Delhi, New Delhi 110021 (India); Vijayan, N. [Department of Physics, Kakatiya University, Warangal 506 009 (India); Abdullah, M.M. [Crystal Growth and XRD Lab, Department of Physics, Jamia Millia Islamia, New Delhi 110 025 (India); Advanced Materials and Nano-research Centre (AMNC), Faculty of Science and Arts, Najran University, P.O. Box-1988, Najran 11001 (Saudi Arabia); Ganesh, V. [Department of Physics, Kakatiya University, Warangal 506 009 (India); Wahab, M.A., E-mail: aries.pre84@gmail.com [Crystal Growth and XRD Lab, Department of Physics, Jamia Millia Islamia, New Delhi 110 025 (India)

    2013-10-01

    In the present work, we have grown single crystals of L-proline cadmium chloride monohydrate (LPCCM) by slow evaporation solution technique (SEST) at room temperature and recorded their live growth kinetics with the help of inverted microscope. Crystal size at various stages of growth and its corresponding morphology was also recorded. Powder X-ray diffraction (PXRD) analysis of LPCCM single crystals confirmed the orthorhombic structure. Respective values of crystallite size, strain and dislocation density have been calculated using PXRD data. Metal complex coordination of the single crystal is studied by FTIR spectroscopic. The optical properties of the grown crystals were investigated through UV–VIS spectroscopic studies and shows that the crystals have very low absorption in entire characterized wavelength range 200–800 nm. The optical band gap was calculated and found to be ∼5.6 eV. Optical constants of the material is determined by theoretical calculations. The chemical etching study was also carried out to study the density of defects in the grown crystals. The photoluminous excitation and emission spectra and thermal property by TGA/DTA curve were recorded. Further, the mechanical properties have been studied using Vicker's microhardness tester as well as many parameters such as fracture toughness (K{sub c}), Brittleness index (B{sub i}) and yield strength (σ{sub ν}) are presented. Dielectric studies have been carried out with varying frequency and temperatures. - Highlights: • The morphology of LPCCM crystal was observed during growth under inverted microscope. • Observation also shows defects also grows with the growth of crystal. • Positive temperature coefficient is observed. • The optical study shows its suitability for photonics and optical applications.

  6. Skylab experiments. Volume 3: Materials science. [Skylab experiments on metallurgy, crystal growth, semiconductors, and combustion physics in weightless environment for high school level education

    Science.gov (United States)

    1973-01-01

    The materials science and technology investigation conducted on the Skylab vehicle are discussed. The thirteen experiments that support these investigations have been planned to evaluate the effect of a weightless environment on melting and resolidification of a variety of metals and semiconductor crystals, and on combustion of solid flammable materials. A glossary of terms which define the space activities and a bibliography of related data are presented.

  7. Hydrothermal crystal growth of oxides for optical applications

    Science.gov (United States)

    McMillen, Colin David

    2007-12-01

    The manipulation of light has proven to be an integral part of today's technology-based society. In particular, there is great interest in obtaining coherent radiation in all regions of the optical spectrum to advance technology in military, medical, industrial, scientific and consumer fields. Exploring new crystal growth techniques as well as the growth of new optical materials is critical in the advancement of solid state optics. Surprisingly, the academic world devotes little attention to the growth of large crystals. This shortcoming has left gaps in the optical spectrum inaccessible by solid state devices. This dissertation explores the hydrothermal crystal growth of materials that could fill two such gaps. The first gap exists in the deep-UV region, particularly below 200 nm. Some materials such as LiB3O5 and beta-BaB2O4 can generate coherent light at wavelengths as low as 205 nm. The growth of these materials was explored to investigate the feasibility of the hydrothermal method as a new technique for growing these crystals. Particular attention was paid to the descriptive chemistry surrounding these systems, and several novel structures were elucidated. The study was also extended to the growth of materials that could be used for the generation of coherent light as low as 155 nm. Novel synthetic schemes for Sr2Be2B2O7 and KBe2BO 3F2 were developed and the growth of large crystals was explored. An extensive study of the structures, properties and crystal growth of related compounds, RbBe2BO3F2 and CsBe2BO 3F2, was also undertaken. Optimization of a number of parameters within this family of compounds led to the hydrothermal growth of large, high quality single crystal at rates suitable for large-scale growth. The second gap in technology is in the area of high average power solid state lasers emitting in the 1 mum and eye-safe (>1.5 mum) regions. A hydrothermal technique was developed to grow high quality crystals of Sc 2O3 and Sc2O3 doped with suitable

  8. Promising electron mobility and high thermal conductivity in Sc2CT2 (T = F, OH) MXenes.

    Science.gov (United States)

    Zha, Xian-Hu; Zhou, Jie; Zhou, Yuhong; Huang, Qing; He, Jian; Francisco, Joseph S; Luo, Kan; Du, Shiyu

    2016-03-21

    MXenes, the new 2D transition metal carbides and nitrides, have recently attracted extensive attention due to their diverse applications and excellent performances. However, the thermal and electrical properties of most MXene materials are yet to be studied. In this work, we investigate the electrical and thermal properties of semiconducting Sc2CT2 (T = F, OH) MXenes using first-principles calculations. Both of the Sc2CT2 (T = F, OH) MXenes are determined to show excellent carrier mobilities. The electron mobility in the Sc2CF2 MXene is found to be strongly anisotropic at room temperature, with values of 5.03 × 10(3) and 1.07 × 10(3) cm(2) V(-1) s(-1) in the zigzag and armchair directions, respectively. The predicted electron mobility in the zigzag direction of the Sc2CF2 is nearly four-fold that in the armchair direction of the promising semiconductor phosphorene. In contrast to Sc2CF2, Sc2C(OH)2 presents approximately isotropic electron mobility. The values at room temperature in the zigzag and armchair directions are calculated as 2.06 × 10(3) cm(2) V(-1) s(-1) and 2.19 × 10(3) cm(2) V(-1) s(-1), respectively. In regard to the thermal properties, the thermal conductivities of the Sc2CT2 (T = F, OH) MXenes have been determined. The predicted values are higher than those of most metals and semiconducting low-dimensional materials, such as monolayer MoS2 and phosphorene. In particular, the room-temperature thermal conductivity along the Sc2CF2 armchair direction has been determined to be as high as 472 W m(-1) K(-1) based on a flake length of 5 μm, which is even higher than that of the best traditional conductor silver. The corresponding value in the zigzag direction of Sc2CF2 is calculated to be 178 W m(-1) K(-1). The thermal conductivity in Sc2C(OH)2 is less anisotropic and lower compared to that in Sc2CF2. The room-temperature value in the armchair (zigzag) direction is determined to be 173 W m(-1) K(-1) (107 W m(-1) K(-1)). Based on their excellent

  9. Effective inhibition of the early copper ion burst release with ultra-fine grained copper and single crystal copper for intrauterine device application.

    Science.gov (United States)

    Xu, X X; Nie, F L; Wang, Y B; Zhang, J X; Zheng, W; Li, L; Zheng, Y F

    2012-02-01

    To solve the main problems of existing coarse grained copper (CG Cu) intrauterine devices (IUD)-namely burst release and a low transfer efficiency of the cupric ions during usage-ultra-fine grained copper (UFG Cu) and single crystal copper (SC Cu) have been investigated as potential substitutes. Their corrosion properties with CG Cu as a control have been studied in simulated uterine fluid (SUF) under different conditions using electrochemical measurement methods. Long-term immersion of UFG Cu, SC Cu and CG Cu samples in SUF at 37 °C have been studied for 300 days. A lower copper ion burst release and a higher efficiency release of cupric ions were observed for UFG Cu and SC Cu compared with CG Cu in the first month of immersion and 2 months later. The respective corrosion mechanisms for UFG Cu, SC Cu and CG Cu in SUF are proposed. In vitro biocompatibility tests show a better cellular response to UFG Cu and SC Cu than CG Cu. In terms of instantaneous corrosion behavior, long-term corrosion performance and in vitro biocompatibility, the three pure copper materials follow the order: UFG Cu>SC Cu>CG Cu, which indicates that UFG Cu could be the most suitable candidate material for intrauterine devices.

  10. NiO-ScSZ and Ni 0.9Mg 0.1O-ScSZ-based anodes under internal dry reforming of simulated biogas mixtures

    Science.gov (United States)

    Shiratori, Y.; Sasaki, K.

    Solid oxide fuel cells (SOFCs) with NiO-ScSZ and Ni 0.9Mg 0.1O-ScSZ-based anodes were operated by directly feeding a fuel mixture of CH 4, CO 2 and N 2 (CH 4 to CO 2 ratio of 3:2). Stable operation under constant current load (200 mA cm -2) was achieved with a NiO-ScSZ type anode during 200 h operating hours at 900 °C. Less stable operation occurred with a Ni 0.9Mg 0.1O-ScSZ type anode. In the case of SOFC with Ni 0.9Mg 0.1O-ScSZ as the anode, the methane reforming activity was higher than that with NiO-ScSZ. This was explained by change in the microstructure promoting reforming reactions. However, the addition of MgO resulted in degradation of electrochemical performance due to increase in ohmic resistance of the anode material during operation.

  11. Sc3N and Sc2C2 encapsulated B40: Smarter than its carbon analogue

    Science.gov (United States)

    Shah, Esha V.; Roy, Debesh R.

    2016-10-01

    A detailed comparative investigation on the recently synthesised B40 and C40 along with their metal nitride (Sc3N)and carbide (Sc2C2) encapsulated endohedral fullerenes, is performed under density functional theory for the first time. The structures, electronic, thermodynamic and magnetic properties of all the considered compounds are explored in detail. The present study identifies borospherene (B40) and its encapsulated nitride (Sc3N@B40) and carbide (Sc2C2@B40) endohedral borofullerenes as the better candidates for future novel nano-applications compared to their carbon bucky ball analogues.

  12. Growth, optical, thermal, mechanical and dielectric studies of sodium succinate hexahydrate (β phase) single crystal: A promising third order NLO material

    Science.gov (United States)

    Mageshwari, P. S. Latha; Priya, R.; Krishnan, S.; Joseph, V.; Das, S. Jerome

    2016-11-01

    A third order nonlinear optical (NLO)single crystals of sodium succinate hexahydrate (SSH) (β phase) has been grown by a slow evaporation growth technique using aqueous solution at ambient temperature. The lattice parameters and morphology of SSH were determined by single crystal X-ray diffraction analysis. SSH crystallizes in centrosymmetric monoclinic system with space group P 21 / c and the crystalline purity was analyzed by powder X-ray diffraction analysis. The UV-vis-NIR spectrum reveals that the crystal is transparent in the entire visible region. The recorded FT-IR spectrum verified the presence of various functional groups in the material. NMR analysis of the grown crystal confirms the structural elucidation and detects the major and minor functional groups present in the title compound. ICP-OES analysis proved the presence of sodium in SSH. TG-DTA/DSCanalysis was used to investigate the thermal stability of the material. The dielectric permittivity and dielectric loss of SSH were carried out as a function of frequency for different temperatures and the results were discussed. The mechanical stability was evaluated from Vicker's microhardness test. The third order nonlinear optical properties of SSH has been investigated employing Z-scan technique with He-Ne laser operating at 632.8 nm wavelength.

  13. Ca10Li(VO4)7:Nd3+, a promising laser material: growth, structure and spectral characteristics of a Czochralski-grown single crystal

    Science.gov (United States)

    Kosmyna, M. B.; Nazarenko, B. P.; Puzikov, V. M.; Shekhovtsov, A. N.; Paszkowicz, W.; Behrooz, A.; Romanowski, P.; Yasukevich, A. S.; Kuleshov, N. V.; Demesh, M. P.; Wierzchowski, W.; Wieteska, K.; Paulmann, C.

    2016-07-01

    Pure and Nd-doped Ca10Li(VO4)7 single crystals were grown by the Czochralski method. The structure of Ca10Li(VO4)7 single crystal was refined starting from a model of Ca10K(VO4)7 using the powder diffraction data collected at a laboratory high-resolution diffractometer. The defect structure of the single crystal was studied with the use of both, high-resolution diffraction using a laboratory instrument and X-ray topographic techniques employing synchrotron radiation at the Hasylab laboratory (Hamburg). Polarized absorption and luminescence spectra of Nd-doped Ca10Li(VO4)7 crystal were investigated in details. The laser oscillation was obtained under flash lamp pumping and the slope efficiency of 0.87% was achieved in the free-running mode. Preliminary examination of lasing properties points that Ca10Li(VO4)7:Nd crystal can be a highly efficient solid state laser medium. Crystals of this kind are expected to be suitable for application as efficient non-linear optics materials.

  14. Binary colloidal crystals

    NARCIS (Netherlands)

    Christova-Zdravkova, C.G.

    2005-01-01

    Binary crystals are crystals composed of two types of particles having different properties like size, mass density, charge etc. In this thesis several new approaches to make binary crystals of colloidal particles that differ in size, material and charge are reported We found a variety of crystal st

  15. Synthesis, crystal growth and characterization of bioactive material: 2-amino-1H-benzo[d]imidazol-3-ium salicylate single crystal-a proton transfer molecular complex

    Science.gov (United States)

    Fathima, K. Saiadali; Anitha, K.

    2017-05-01

    The 1:1 molecular adducts 2-aminobenzimidazolium salicylate (ABIS) single crystal was synthesized and grown from 2-aminobenzimidazole (ABI) as a donor and salicylic acid (SA) as an acceptor. The cell parameter was determined using single crystal X-Ray diffraction method and the complex ABIS belongs to monoclinic system. The spectroscopic studies showed that ABIS crystal was an ion pair complex. The FTIR and Raman spectra showed that the presence of O-H, C=N, C=O vibration which confirms the proton transfer from SA to ABI. The UV-Vis spectrum exhibited a visible band at 359nm for ABIS due to the salicylate anion of the molecule. Further the antimicrobial activity of ABIS complex against Staphylococcus aureus, klebsiella pneumonia, Pseudomonas eruginos and E.coli pathogens was investigated. So the complex molecule inhibits both Gram positive and Gram negative bacterial. It is found that benzimidazole with aminogroup at position 2 increases the general antimicrobial activities of ABIS crystal.

  16. Properties of the Band Gaps in 1D Ternary Lossy Photonic Crystal Containing Double-Negative Materials

    Directory of Open Access Journals (Sweden)

    Alireza Aghajamali

    2014-01-01

    Full Text Available Theoretically, the characteristics matrix method is employed to investigate and compare the properties of the band gaps of the one-dimensional ternary and binary lossy photonic crystals which are composed of double-negative and double-positive materials. This study shows that by varying the angle of incidence, the band gaps for TM and TE waves behave differently in both ternary and binary lossy structures. The results demonstrate that, by increasing the angle of incidence for the TE wave, the width and the depth of zero-n¯, zero-μ, and Bragg gap increase in both ternary and binary structures. On the other hand, the enhancement of the angle of incidence for the TM wave contributes to reduction of the width and the depth of the zero-n¯ and Bragg gaps, and they finally disappear for incidence angles greater than 50° and 60° for the binary structure and 40° and 45° for the ternary structures, respectively. In addition, the details of the edges of the band gaps variations as a function of incidence angle for both structures are studied.

  17. Photo-electrochemical and physical characterizations of a new single crystal POM-based material. Application in photocatalysis

    Science.gov (United States)

    Meziani, D.; Abdmeziem, K.; Bouacida, S.; Trari, M.

    2016-12-01

    A new inorganic-organic hybrid material [(H2pip)3][α-PW12O40]2·4H2O, prepared by hydrothermal method, was structurally characterized by single-crystal X-ray diffraction. The compound based on a Keggin-type polyoxotungstate and piperazine (pip) displays a hybrid framework built from two (α-Keggin)3- polyoxoanions and three (H2pip)2+ hydrogen-bonded fragments, forming 3-D supramolecular architecture. The diffuse reflectance spectrum shows two optical transitions directly (3.27 eV) and indirectly (3.12 eV) allowed. The electrical conductivity follows an exponential law, indicating a semiconducting comportment with activation energy of 14 meV. The Mott-Schottky characteristic, plotted in Na2SO4 (0.5 M) solution indicates n-type conduction with a flat band potential of -0.084 VSCE and electrons density of 4.24 × 1018 cm-3. As application, the photo-degradation of methylene blue (MB) upon UV irradiation was successfully achieved by OH• radicals. The improved activity is attributed to the potentials closeness of the valence and conduction bands with the radical levels.

  18. Forming limit prediction using a self-consistent crystal plasticity framework: a case study for body-centered cubic materials

    Science.gov (United States)

    Jeong, Youngung; Pham, Minh-Son; Iadicola, Mark; Creuziger, Adam; Foecke, Timothy

    2016-06-01

    A rate-dependent self-consistent crystal plasticity model was incorporated with the Marciniak-Kuczyński model in order to study the effects of anisotropy on the forming limits of BCC materials. The computational speed of the model was improved by a factor of 24 when running the simulations for several strain paths in parallel. This speed-up enabled a comprehensive investigation of the forming limits of various BCC textures, such as γ , σ , α , η and ɛ fibers and a uniform (random) texture. These simulations demonstrate that the crystallographic texture has significant (both positive and negative) effects on the resulting forming limit diagrams. For example, the γ fiber texture, which is often sought through thermo-mechanical processing due to a high r-value, had the highest forming limit in the balanced biaxial strain path but the lowest forming limit under the plane strain path among the textures under consideration. A systematic investigation based on the results produced by the current model, referred to as ‘VPSC-FLD’, suggests that the r-value does not serve as a good measure of forming limit strain. However, model predictions show a degree of correlation between the r-value and the forming limit stress.

  19. Effect of phonon focusing on Knudsen flow of phonon gas in single-crystal nanowires made of spintronics materials

    Science.gov (United States)

    Kuleev, I. I.; Bakharev, S. M.; Kuleev, I. G.; Ustinov, V. V.

    2017-01-01

    Effect of anisotropy of elastic energy on the phonon propagation in single-crystal nanowires made of Fe, Cu, MgO, InSb, and GaAs materials that are used to fabricate spintronics devices in the regime of the Knudsen flow of phonon gas has been studied. A new method of analyzing the focusing of quasi-transverse modes has been suggested, which made it possible to determine the average values of the densities of phonon states in the regions of focusing and defocusing slow and fast quasi-transverse modes. The effect of phonon focusing on the anisotropy of heat conductivity and lengths of the phonon free paths has been analyzed for all acoustic modes that exist in spintronics nanostructures. It has been shown that for all the nanowires investigated the angular dependences of the free paths of fast and slow transverse modes in the {100} and {110} planes correlate with the angular dependences of the densities of phonon states for these modes. Directions of the heat flux that ensure the maximum and minimum phonon heat conductivity in the nanowires have been determined.

  20. Simple method for the determination of refractive indices and loss parameters for liquid-crystal materials in the millimeter-wave region.

    Science.gov (United States)

    Nose, Toshiaki; Honma, Michinori; Nozokido, Tatsuo; Mizuno, Koji

    2005-03-01

    A reflection-type liquid crystal (LC) test cell is prepared with a rectangular waveguide for investigation of a novel method to determine refractive indices and loss parameters of nematic liquid-crystal materials. As the bottom of the test cell is sealed with a glass window and the top of the cell is capped with a metal-tipped movable reflector after the LC materials are injected, both ends of the waveguide test cell have large reflectance. Thus the reflection properties of the LC test cell can be well described by a multiple-beam interference model. A simple method for the determination of refractive indices from the reflection measurement data is proposed based on results of some investigations with the theoretical model. Commercially available LC materials have been measured with this method at a millimeter-wave frequency (50 GHz) by use of a simple experimental setup with a Gunn oscillator and a diode detector.

  1. Water diffusion in atmospherically relevant ?-pinene secondary organic material? ?Electronic supplementary information (ESI) available. See DOI: 10.1039/c5sc00685f Click here for additional data file.

    OpenAIRE

    Price, Hannah C.; Mattsson, Johan; Zhang, Yue; Allan K. Bertram; Davies, James F.; Grayson, James W.; Martin, Scot T.; O'Sullivan, Daniel; Reid, Jonathan P.; Rickards, Andrew M J; Murray, Benjamin J.

    2015-01-01

    Secondary organic material (SOM) constitutes a large mass fraction of atmospheric aerosol particles. Understanding its impact on climate and air quality relies on accurate models of interactions with water vapour. Recent research shows that SOM can be highly viscous and can even behave mechanically like a solid, leading to suggestions that particles exist out of equilibrium with water vapour in the atmosphere. In order to quantify any kinetic limitation we need to know water diffusion coeffic...

  2. Insights into the crystal chemistry of Earth materials rendered by electron density distributions: Pauling's rules revisited

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, Gerald V.; Ross, Nancy L.; Cox, David F.; Rosso, Kevin M.

    2014-05-20

    coordination number of the atom is determined uniquely independent of the asphericity and sizes of the atom. A power law connection established between the bond lengths and bond strengths for crystals and molecules is mirrored by a comparable power law connection between bond length and the accumulation of the electron density between bonded pairs of atoms, a connection that is consistent with Pauling's electroneutrality postulate that the charges of the atoms in an oxide are negligibly small. The connection indicates that a one-to-one correspondence exists between the accumulation between a pair of bonded atoms and the Pauling bond strength for M-O bonded interaction for all atoms of the periodic table. The connection provides a common basis for understanding the success of the manifold applications that have been made with the bond valence theory model together with the modeling of crystal structures, chemical zoning, leaching and cation transport in batteries and the like. We believe that the wide spread applications of the model in mineralogy and material science owes much of its success to the direct connection between bond strength and the quantum mechanical observable, the electron density distribution. Comparable power law expressions established for the bonded interactions for both crystals and molecules support Pauling's assertion that his second rule has significance for molecules as well as for crystals. A simple expression is found that provides a one to one connection between the accumulation of the electron density between bonded M and O atoms and the Pauling bond strength for all M atoms of the periodic table with ~ 95 % of the variation of the bond strength being explained in terms of a linear dependence on the accumulated electron density. Compelling evidence is presented that supports the argument that the Si-O bonded interactions for tiny siloxane molecules and silicate crystals are chemically equivalent.

  3. Evanescent waves and deaf bands in sonic crystals

    Directory of Open Access Journals (Sweden)

    V. Romero-García

    2011-12-01

    Full Text Available The properties of sonic crystals (SC are theoretically investigated in this work by solving the inverse problem k(ω using the extended plane wave expansion (EPWE. The solution of the resulting eigenvalue problem gives the complex band structure which takes into account both the propagating and the evanescent modes. In this work we show the complete mathematical formulation of the EPWE for SC and the supercell approximation for its use in both a complete SC and a SC with defects. As an example we show a novel interpretation of the deaf bands in a complete SC in good agreement with multiple scattering simulations.

  4. Evanescent waves and deaf bands in sonic crystals

    Science.gov (United States)

    Romero-García, V.; Garcia-Raffi, L. M.; Sánchez-Pérez, J. V.

    2011-12-01

    The properties of sonic crystals (SC) are theoretically investigated in this work by solving the inverse problem k(ω) using the extended plane wave expansion (EPWE). The solution of the resulting eigenvalue problem gives the complex band structure which takes into account both the propagating and the evanescent modes. In this work we show the complete mathematical formulation of the EPWE for SC and the supercell approximation for its use in both a complete SC and a SC with defects. As an example we show a novel interpretation of the deaf bands in a complete SC in good agreement with multiple scattering simulations.

  5. Sc20C60: a volleyballene

    Science.gov (United States)

    Wang, Jing; Ma, Hong-Man; Liu, Ying

    2016-06-01

    An exceptionally stable hollow cage containing 20 scandium atoms and 60 carbon atoms has been identified. This Sc20C60 molecular cluster has a Th point group symmetry and a volleyball-like shape that we refer to below as ``Volleyballene''. Electronic structure analysis shows that the formation of delocalized π bonds between Sc atoms and the neighboring pentagonal rings made of carbon atoms is crucial for stabilizing the cage structure. A relatively large HOMO-LUMO gap (~1.4 eV) was found. The results of vibrational frequency analysis and molecular dynamics simulations both demonstrate that this Volleyballene molecule is exceptionally stable.An exceptionally stable hollow cage containing 20 scandium atoms and 60 carbon atoms has been identified. This Sc20C60 molecular cluster has a Th point group symmetry and a volleyball-like shape that we refer to below as ``Volleyballene''. Electronic structure analysis shows that the formation of delocalized π bonds between Sc atoms and the neighboring pentagonal rings made of carbon atoms is crucial for stabilizing the cage structure. A relatively large HOMO-LUMO gap (~1.4 eV) was found. The results of vibrational frequency analysis and molecular dynamics simulations both demonstrate that this Volleyballene molecule is exceptionally stable. Electronic supplementary information (ESI) available: Sc20C60: a Volleyballene_SI. See DOI: 10.1039/c5nr07784b

  6. Zero lattice mismatch and twin-free single crystalline ScN buffer layers for GaN growth on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Lupina, L.; Zoellner, M. H.; Dietrich, B.; Capellini, G. [IHP, Im Technologiepark 25, 15236 Frankfurt, Oder (Germany); Niermann, T.; Lehmann, M. [Technische Universität Berlin, Institut für Optik und Atomare Physik, Straße des 17. Juni 135, 10623 Berlin (Germany); Thapa, S. B.; Haeberlen, M.; Storck, P. [SILTRONIC AG, Hanns-Seidel-Platz 4, 81737 München (Germany); Schroeder, T. [IHP, Im Technologiepark 25, 15236 Frankfurt, Oder (Germany); BTU Cottbus, Konrad-Zuse-Str. 1, 03046 Cottbus (Germany)

    2015-11-16

    We report the growth of thin ScN layers deposited by plasma-assisted molecular beam epitaxy on Sc{sub 2}O{sub 3}/Y{sub 2}O{sub 3}/Si(111) substrates. Using x-ray diffraction, Raman spectroscopy, and transmission electron microscopy, we find that ScN films grown at 600 °C are single crystalline, twin-free with rock-salt crystal structure, and exhibit a direct optical band gap of 2.2 eV. A high degree of crystalline perfection and a very good lattice matching between ScN and GaN (misfit < 0.1%) makes the ScN/Sc{sub 2}O{sub 3}/Y{sub 2}O{sub 3} buffer system a very promising template for the growth of high quality GaN layers on silicon.

  7. {sup 27}Al and {sup 45}Sc NMR spectroscopy on ScT{sub 2}Al and Sc(T{sub 0.5}T{sup '}{sub 0.5}){sub 2}Al (T = T{sup '} = Ni, Pd, Pt, Cu, Ag, Au) Heusler phases and superconductivity in Sc(Pd{sub 0.5}Au{sub 0.5}){sub 2}Al

    Energy Technology Data Exchange (ETDEWEB)

    Benndorf, Christopher [Institut fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Institut fuer Physikalische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Niehaus, Oliver; Janka, Oliver [Institut fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Eckert, Hellmut [Institut fuer Physikalische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany)

    2015-02-15

    The intermetallic Heusler compounds with ScT{sub 2}Al and Sc(T{sub 0.5}T{sup '}{sub 0.5}){sub 2}Al composition with T = T{sup '} = Ni, Pd, Pt, Cu, Ag, Au were synthesized from the elements by arc melting. They crystallize in the cubic MnCu{sub 2}Al type structure, space group Fm anti 3m. The unit cell parameters were determined by powder X-ray diffraction and the structure of Sc(Pd{sub 0.5}Au{sub 0.5}){sub 2}Al was refined on the basis of single-crystal X-ray diffraction. While the majority of the compounds show Pauli-paramagnetism, ScAu{sub 2}Al and the newly synthesized solid solution Sc(Pd{sub 0.5}Au{sub 0.5}){sub 2}Al exhibit superconductivity with transition temperatures of T{sub C} = 4.4 K and T{sub C} = 3.0(1) K, respectively. The superconducting state of Sc(Pd{sub 0.5}Au{sub 0.5}){sub 2}Al was also investigated by electrical resistivity measurements. All the synthesized compounds were furthermore studied by {sup 27}Al and {sup 45}Sc MAS-NMR spectroscopy. The resonance shifts of the synthesized compounds were determined and in Sc(Pd{sub 1-x}Au{sub x}){sub 2}Al a linear relationship between the resonance shifts and the composition was found. Line broadening effects and enhanced quadrupolar interaction strengths observed in the mixed samples can be attributed to the effect of Pd/Au mixing on the 8c Wyckoff site. The NMR spectroscopic data give no clear evidence for or against Sc/Al site disordering. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Density functional study of $\\rm{AgScO_2}$: Electronic and optical properties

    Indian Academy of Sciences (India)

    K C BHAMU; JAGRATI SAHARIYA; RISHI VYAS; K R PRIOLKAR

    2017-07-01

    This paper focusses on the electronic and optical properties of scandium-based silver delafossite $\\rm{(AgScO_2)}$ semiconductor. The density functional theory (DFT) in the framework of full potential linearized augmented plane wave (FP-LAPW) scheme has been used for the present calculations with local densityapproximation (LDA) and generalized gradient approximation (GGA). Electronic properties deal with energy bands and density of states (DOSs), while optical properties describe refractive index and absorption coefficient.The energy bands are interpreted in terms of DOSs. The computed value of band gap is in agreement with that reported in the literature. Our results predict $\\rm{AgScO_2}$ as indirect band-gap semiconductor. Our calculated value of the refractive index in zero frequency limits is 2.42. The absorption coefficient predicts the applicability of $\\rm{AgScO_2}$ in solar cells and flat panel liquid crystal display as a transparent top window layer.

  9. Density functional study of AgScO_2: Electronic and optical properties

    Science.gov (United States)

    Bhamu, K. C.; Sahariya, Jagrati; Vyas, Rishi; Priolkar, K. R.

    2017-07-01

    This paper focusses on the electronic and optical properties of scandium-based silver delafossite (AgScO_2) semiconductor. The density functional theory (DFT) in the framework of full potential linearized augmented plane wave (FP-LAPW) scheme has been used for the present calculations with local density approximation (LDA) and generalized gradient approximation (GGA). Electronic properties deal with energy bands and density of states (DOSs), while optical properties describe refractive index and absorption coefficient. The energy bands are interpreted in terms of DOSs. The computed value of band gap is in agreement with that reported in the literature. Our results predict AgScO_2 as indirect band-gap semiconductor. Our calculated value of the refractive index in zero frequency limits is 2.42. The absorption coefficient predicts the applicability of AgScO_2 in solar cells and flat panel liquid crystal display as a transparent top window layer.

  10. A Study on the Effects on Low Cycle Fatigue Life of a High Pressure Turbine Nozzle due to the Perturbation of Crystal Orientation of Grain of DS Materials

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Jae Sung; Kang, Young Seok; Rhee, Dong Ho [Korea Aerospace Research Institute, Daejeon (Korea, Republic of)

    2016-07-15

    High pressure components of a gas turbine engine are generally made of nickel-base superalloys, using precision casting process due to complicated geometries with intricate channels and cooling holes. Turbine components manufactured from directionally solidified and single crystal materials have columnar grains; however, it is found that the crystals do not grow in its preferred direction, although the orientation can be controlled. This anisotropy can lead to the variations of elastic and Hill's parameters in constitutive equations, and they alter stress distributions and the low cycle fatigue life. We aims to evaluate the effects of perturbed crystal orientations on the structural integrity of a directionally solidified nozzle using low cycle fatigue life. We also attempt to show the necessity for the control of allowed manufacturing errors and stochastic analysis. Our approaches included conjugate heat transfer and structural analysis, along with low cycle fatigue life assessment.

  11. Detection of low concentration formaldehyde gas by photonic crystal sensor fabricated by nanoimprint process in polymer material

    NARCIS (Netherlands)

    Boersma, A.; Ee, R.J. van; Stevens, R.S.A.; Saalmink, M.; Charlton, M.D.B.; Pollard, M.E.; Chen, R.; Kontturi, V.; Karioja, P.; Alajoki, T.

    2014-01-01

    This paper describes experimental measurement results for photonic crystal sensor devices which have been functionalized for gas sensing applications. The sensor consists of a two dimensional photonic crystal etched into a slab waveguide having a refractive index of 1.7-1.9. Test devices were fabric

  12. Material properties of pulsed-laser crystallized Si thin films grown on yttria-stabilized zirconia crystallization-induction layers by two-step irradiation method

    Science.gov (United States)

    Thi Kieu Lien, Mai; Horita, Susumu

    2016-03-01

    Amorphous Si thin films on yttria-stabilized zirconia (YSZ) layers were crystallized widely in solid phase by the two-step method with a pulsed laser, moving the sample stage. The crystalline quality, impurity diffusion, and electrical properties of the crystallized Si films were investigated. It was found that the crystallinity of the Si thin films was improved and their surface was smooth without an incubation layer at the interface, indicating the uniform crystallinity of Si on YSZ. The diffusion of Zr and Y into the Si thin films was as small as or smaller than the order of 1017 atoms/cm3. We evaluated the electrical properties of carrier concentration and Hall mobility of the Si thin films with/without YSZ layers by using the resistivity and AC Hall effect measurements. The temperature and doping concentration dependences were measured for both undoped and P-doped films. It was found that both the undoped and P-doped Si/YSZ/glass films showed higher mobilities and carrier concentrations (and therefore higher conductivities), which indicate a smaller number of defects, than the Si/glass films. This suggested that the Si film crystallized on the YSZ layer is more suitable for application to electronic devices than the Si film on glass.

  13. Recrystallization and Morphology of Microstructure in Al-Sc Alloys

    Institute of Scientific and Technical Information of China (English)

    Zhang Jun; Zhang Zonghua

    2007-01-01

    Minor addition of Sc to aluminum results in the rapid precipitation of homogeneously distributed Al3Sc dispersoids. The presence of Al3Sc dispersoids is more effective recrystallization inhibitors. Our work established the precipitation of homogeneously distributed Al3Sc dispersoids, which are coherent with the matrix, have the L12 structure. It was also established that the addition of Sc was effective in improving the recrystallization resistance.

  14. Optical transmittance investigation of 1-keV ion-irradiated sapphire crystals as potential VUV to NIR window materials of fusion reactors

    Directory of Open Access Journals (Sweden)

    Keisuke Iwano

    2016-10-01

    Full Text Available We investigate the optical transmittances of ion-irradiated sapphire crystals as potential vacuum ultraviolet (VUV to near-infrared (NIR window materials of fusion reactors. Under potential conditions in fusion reactors, sapphire crystals are irradiated with hydrogen (H, deuterium (D, and helium (He ions with 1-keV energy and ∼ 1020-m-2 s-1 flux. Ion irradiation decreases the transmittances from 140 to 260 nm but hardly affects the transmittances from 300 to 1500 nm. H-ion and D-ion irradiation causes optical absorptions near 210 and 260 nm associated with an F-center and an F+-center, respectively. These F-type centers are classified as Schottky defects that can be removed through annealing above 1000 K. In contrast, He-ion irradiation does not cause optical absorptions above 200 nm because He-ions cannot be incorporated in the crystal lattice due to the large ionic radius of He-ions. Moreover, the significant decrease in transmittance of the ion-irradiated sapphire crystals from 140 to 180 nm is related to the light scattering on the crystal surface. Similar to diamond polishing, ion irradiation modifies the crystal surface thereby affecting the optical properties especially at shorter wavelengths. Although the transmittances in the VUV wavelengths decrease after ion irradiation, the transmittances can be improved through annealing above 1000 K. With an optical transmittance in the VUV region that can recover through simple annealing and with a high transparency from the ultraviolet (UV to the NIR region, sapphire crystals can therefore be used as good optical windows inside modern fusion power reactors in terms of light particle loadings of hydrogen isotopes and helium.

  15. K2SC: K2 Systematics Correction

    Science.gov (United States)

    Aigrain, Suzanne; Parviainen, Hannu; Pope, Benjamin

    2016-05-01

    K2SC (K2 Systematics Correction) models instrumental systematics and astrophysical variability in light curves from the K2 mission. It enables the user to remove both position-dependent systematics and time-dependent variability (e.g., for transit searches) or to remove systematics while preserving variability (for variability studies). K2SC automatically computes estimates of the period, amplitude and evolution timescale of the variability for periodic variables and can be run on ASCII and FITS light curve files. Written in Python, this pipeline requires NumPy, SciPy, MPI4Py, Astropy (ascl:1304.002), and George (ascl:1511.015).

  16. Norma Audio Revo SC-/PA-150

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Norma audio是意大利一间顶级HI-Fi音响器材生产商。这款IRevo SC-2/PA-150为正是公司旗下的一款高端型号产品。其中,Revo SC-2前置放大器的放大电路以低噪音、高速和宽频作为设计重点,能反映出音频信号中的每一个细节。

  17. Mn3O4 nano-sized crystals: Rapid synthesis and extension to preparation of nanosized LiMn2O4 materials

    Indian Academy of Sciences (India)

    Xiao-Ling Cui; Yong-Li Li; Shi-You Li; Guo-Cun Sun; Jin-Xia Ma; Lu Zhang; Tian-Ming Li; Rong-Bo Ma

    2014-05-01

    With a novel gas-liquid reaction, a facile and rapid method has been successfully developed for the synthesis of nano-sized Mn3O4 crystals. Coupled with complementary experiments, preparation mechanisms of Mn(II) and Mn(III)Mn(III)Mn(II) coordination complexes as well as nano-sized Mn3O4 crystals are studied. Besides, as the extension of synthesis of nano-sized Mn3O4 crystals, the intermediate ammonia alkaline solution containing Mn(III)Mn(III)Mn(II) coordination complexes, which tend to decompose into nano-sized Mn3O4 crystals spontaneously, are used to prepare nanosized LiMn2O4 materials. Although any physical treatment has been done to disperse powders, the as-synthesized LiMn2O4 nanoparticles are still existence with homogeneous size distribution (about 24.2 nm) without any obvious agglomeration. That is to say, the novel method is constructive not only to accelerate reaction rates for the elevated oxidation state of manganese ions, but also to prepare dispersed nanosized LiMn2O4 materials with good electrochemical properties.

  18. AlScN thin film based surface acoustic wave devices with enhanced microfluidic performance

    Science.gov (United States)

    Wang, W. B.; Fu, Y. Q.; Chen, J. J.; Xuan, W. P.; Chen, J. K.; Wang, X. Z.; Mayrhofer, P.; Duan, P. F.; Bittner, A.; Schmid, U.; Luo, J. K.

    2016-07-01

    This paper reports the characterization of scandium aluminum nitride (Al1-x Sc x N, x  =  27%) films and discusses surface acoustic wave (SAW) devices based on them. Both AlScN and AlN films were deposited on silicon by sputtering and possessed columnar microstructures with (0 0 0 2) crystal orientation. The AlScN/Si SAW devices showed improved electromechanical coupling coefficients (K 2, ~2%) compared with pure AlN films (droplets, and the acoustic streaming and pumping velocities were 2  ×  and 3  ×  those of the AlN/Si SAW devices, respectively. Mechanical characterization showed that the Young’s modulus and hardness of the AlN film decreased significantly when Sc was doped, and this was responsible for the decreased acoustic velocity and resonant frequency, and the increased temperature coefficient of frequency, of the AlScN SAW devices.

  19. Surrogate Seeds For Growth Of Crystals

    Science.gov (United States)

    Shlichta, Paul J.

    1989-01-01

    Larger crystals of higher quality grown. Alternative method for starting growth of crystal involves use of seed crystal of different material instead of same material as solution. Intended for growing single-crystal proteins for experiments but applicable in general to growth of crystals from solutions and to growth of semiconductor or other crystals from melts.

  20. 41 CFR 102-38.365 - Is a holding agency required to report property in “scrap” condition to its selected SC?

    Science.gov (United States)

    2010-07-01

    ... Sales Program § 102-38.365 Is a holding agency required to report property in “scrap” condition to its selected SC? No. Property which has no value except for its basic material content (scrap material) may be... agency should consult the SC(s) selected by the holding agency as to the feasibility of selling the...

  1. Ab Initio Calculations and Synthesis of Sc2InC-Y2InC Solid Solution

    Science.gov (United States)

    2010-02-03

    tribological materials. It will study a solid solution of this fascinating new class of nanolaminated materials using both theoretical and experimental means...Sc2InC-Y2InC solid solution using ab initio calculations and 2) to synthesize Sc2InC-Y2InC thin films using magnetron sputtering and to determine the correlation between composition, structure, and mechanical properties thereof.

  2. Enrichment of Sc2O3 and TiO2 from bauxite ore residues.

    Science.gov (United States)

    Deng, Bona; Li, Guanghui; Luo, Jun; Ye, Qing; Liu, Mingxia; Peng, Zhiwei; Jiang, Tao

    2017-06-05

    As a major byproduct generated in the alumina industry, bauxite ore residue is an important reserve of scandium and titanium. In this study, the feasibility and mechanism of enriching Sc2O3 and TiO2 from a non-magnetic material, which was obtained from carbothermal reductive roasting and magnetic separation of bauxite ore residue, were investigated based on a two-step (acidic and alkali) leaching process. It was revealed that approximately 78% SiO2 and 30-40% of CaO, FeO and Al2O3 were removed from a non-magnetic material with 0.0134wt.% Sc2O3 and 7.64wt.% TiO2 by phosphoric acidic leaching, while about 95% Al2O3 and P2O5 were further leached by subsequent sodium hydroxide leaching of the upper-stream leach residue. A Sc2O3-, TiO2- rich material containing 0.044wt.% Sc2O3 and 25.5wt.% TiO2 was obtained, the recovery and the enrichment factor of Sc2O3 and TiO2 were about 85% and 5, respectively. The enrichment of Sc2O3 was attributed to higher pH (>3.3) of phosphoric acid solution than its dissolution pH(0), and the enrichment of TiO2 was mainly associated with the insoluble perovskite (CaTiO3) in the acidic solution at ambient temperature. As Sc2O3 and TiO2 cannot be dissolved in the alkali solution, they were further enriched in the leach residue.

  3. Measurement of the SC magnetic field

    CERN Multimedia

    CERN PhotoLab

    1973-01-01

    The 3.5-metre-arm carrying 100 Hall plates used for the measurmeent of the SC magnetic field. The arm rotates in a horizontal plane, its positioning and the data read-out are controlled by an on-line computer.

  4. Magnet measuring equipment of SC2

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    Checking the positioning of the magnet measuring equipment installed between the poles of SC2. The steel structure in front of the magnet is designed to house the rotary condenser and to shield it from the stray magnetic field of the accelerator.

  5. Magnet measuring equipment of SC2

    CERN Multimedia

    1974-01-01

    Checking the positioning of the magnet measuring equipment installed between the poles of SC2. The steel structure in front of the magnet is designed to house the rotary condenser and to shield it from the stray magnetic field of the accelerator. On the left, Marinus van Gulik. (See Photo Archive 7402005 and Annual Report 1974, p. 44.)

  6. The Synchrocyclotron (SC) in building 300

    CERN Multimedia

    Maximilien Brice

    2012-01-01

    The red magnet of CERN's first accelerator, the Synchrocyclotron (SC), has occupied a large part of Hall 300 since it was installed in the late 1950s. The remaining part of the 300-square-metre building has been used as a storage room since the accelerator was shut down in 1990. Now a public exhibition will breathe new life into the hall.

  7. New Materials for Oxygen Reduction Electrodes

    DEFF Research Database (Denmark)

    Johansson, Tobias Peter

    This thesis is concerned with the discovery, characterisation and testing of new catalysts for the oxygen reduction reaction (ORR). A theroretical screening study was performed, in close collaboration with the theory group at the Center for Atomicscale Materials Design (CAMD), searching for catal......This thesis is concerned with the discovery, characterisation and testing of new catalysts for the oxygen reduction reaction (ORR). A theroretical screening study was performed, in close collaboration with the theory group at the Center for Atomicscale Materials Design (CAMD), searching...... as the sputter cleaned Pt3Sc. The deposition of Y on a Pt(111) crystal was then investigated. It was found that when annealing the crystal above 800 K a Pt overlayer was formed on top of a PtxY structure. Low energy electron diffraction (LEED) was used to probe the ordering of the surface and the LEED patterns...

  8. Knowledge insufficient: the management of haemoglobin SC disease.

    Science.gov (United States)

    Pecker, Lydia H; Schaefer, Beverly A; Luchtman-Jones, Lori

    2017-02-01

    Although haemoglobin SC (HbSC) accounts for 30% of sickle cell disease (SCD) in the United States and United Kingdom, evidence-based guidelines for genotype specific management are lacking. The unique pathology of HbSC disease is complex, characterized by erythrocyte dehydration, intracellular sickling and increased blood viscosity. The evaluation and treatment of patients with HbSC is largely inferred from studies of SCD consisting mostly of haemoglobin SS (HbSS) patients. These studies are underpowered to allow definitive conclusions about HbSC. We review the pathophysiology of HbSC disease, including known and potential differences between HbSS and HbSC, and highlight knowledge gaps in HbSC disease management. Clinical and translational research is needed to develop targeted treatments and to validate management recommendations for efficacy, safety and impact on quality of life for people with HbSC. © 2016 John Wiley & Sons Ltd.

  9. Crystal structure analysis of intermetallic compounds

    Science.gov (United States)

    Conner, R. A., Jr.; Downey, J. W.; Dwight, A. E.

    1968-01-01

    Study concerns crystal structures and lattice parameters for a number of new intermetallic compounds. Crystal structure data have been collected on equiatomic compounds, formed between an element of the Sc, Ti, V, or Cr group and an element of the Co or Ni group. The data, obtained by conventional methods, are presented in an easily usable tabular form.

  10. Photonic Material Selection of Scintillation Crystals Using Monte Carlo Method for X-Ray Detection in Industrial Computed Tomography

    Directory of Open Access Journals (Sweden)

    Peng He

    2014-01-01

    Full Text Available Currently industrial X-CT system is designed according to characteristics of test objects, and test objects determine industrial X-CT system structure, X-ray detector/sensor property, scanning mode, and so forth. So there are no uniform standards for the geometry size of scintillation crystals of detector. Moreover, scintillation crystals are usually mixed with some highly toxic impurity elements, such as Tl and Cd. Thus, it is indispensable for establishing guidelines of engineering practice to simulate X-ray detection performances of different scintillation crystals. This paper focuses on how to achieve high efficient X-ray detection in industrial X-CT system which used Monte Carlo (MC method to study X-ray energy straggling characteristics, full energy peak efficiency, and conversion efficiency of some scintillation crystals (e.g., CsI(Tl, NaI(Tl, and CdWO4 after X-ray interacted with these scintillation crystals. Our experimental results demonstrate that CsI(Tl scintillation crystal has the advantages of conversion efficiency, spectral matching, manufacturing process, and full energy peak efficiency; it is an ideal choice for high efficient X-ray detection in industrial X-CT system.

  11. Early Stages of Precipitation Process in Al-(Mn-)Sc-Zr Alloy Characterized by Positron Annihilation

    KAUST Repository

    Vlach, Martin

    2015-01-29

    Thermal effects on the precipitation stages in as-cast Al-0.70 at. pct Mn-0.15 at. pct Sc-0.05 at. pct Zr alloy were studied. The role of lattice defects was elucidated by positron annihilation spectroscopy (lifetime and coincidence Doppler broadening) enabling investigation of solutes clustering at the atomic scale. This technique has never been used in the Al-Sc- and/or Al-Zr-based alloys so far. Studies by positron annihilation were combined with resistometry, hardness measurements, and microstructure observations. Positrons trapped at defects are preferentially annihilated by Sc electrons. Lifetime of trapped positrons indicates that Sc atoms segregate at dislocations. Maximum fraction of positrons annihilated by Sc electrons occurring at 453 K (180 °C) suggests that clustering of Sc bound with vacancies takes place. It is followed by peak of this fraction at 573 K (300 °C). A rise of the contribution of trapped positrons annihilated by Zr electrons starting at 513 K (240 °C) and attaining maximum also at 573 K (300 °C) confirms that Zr participates in precipitation of the Al3Sc particles already at these temperatures. The pronounced hardening at 573 K (300 °C) has its nature in the precipitation of the Al3Sc particles with a Zr-rich shell. The contribution of trapped positrons annihilated by Mn electrons was found to be negligible. © 2015, The Minerals, Metals & Materials Society and ASM International.

  12. Nd and Sc co-doped BiFeO{sub 3} nanopowders displaying enhanced ferromagnetism at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, N., E-mail: netzahualpille.hernandeznv@uanl.edu.mx [Centro de Innovación, Investigación y Desarrollo en Ingeniería y Tecnología, Km. 10 Nueva carretera al Aeropuerto Internacional de Monterrey, PIIT Monterrey, CP 66600 Apodaca, Nuevo León (Mexico); González-González, V.A. [Centro de Innovación, Investigación y Desarrollo en Ingeniería y Tecnología, Km. 10 Nueva carretera al Aeropuerto Internacional de Monterrey, PIIT Monterrey, CP 66600 Apodaca, Nuevo León (Mexico); Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Pedro de Alba S/N, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Dzul-Bautista, I.B. [Centro de Innovación, Investigación y Desarrollo en Ingeniería y Tecnología, Km. 10 Nueva carretera al Aeropuerto Internacional de Monterrey, PIIT Monterrey, CP 66600 Apodaca, Nuevo León (Mexico); Gutiérrez, J.; Barandiarán, J.M. [Basque Center for Materials, Applications and Nanostructures (BCMaterials), Universidad del País Vasco (UPV/EHU), Parque Tecnológico de Bizkaia, Ed. 500, Derio 48160 (Spain); and others

    2015-07-25

    Highlights: • Will study the structure of materials obtained. • A well crystallized BiFeO{sub 3} doped material was obtained without further annealing. • The obtained nanoparticles have sizes less than 60 nm. • Enhanced ferromagnetic materials was obtained. - Abstract: We have developed a novel synthetic route for the preparation of single phase Nd{sub x}Bi{sub 1−x}Fe{sub 0.95}Sc{sub 0.05}O{sub 3} (NBFSO) nanopowder materials by a surfactant-assisted combustion-derived method. Rietveld fitting of the Powder X-ray diffraction data showed the nanopowder structure evolves from a distorted rhombohedral BiFeO{sub 3} crystalline structure (R3c, x = 0) to a orthorhombic structure (Pbnm, x = 0.10). Differential thermal analysis and thermogravimetric analysis (DTA/TGA) showed a crystallization temperature of 200 °C. Transmission electron microscopy (TEM) images revealed the presence of clusters formed by fine nanoparticles less than 60 nm in diameter. From Raman spectroscopy, the change from rhombohedral structure to cubic structure was observed by a drastic intensity reduction of the A{sub 1}{sup −2} and A{sub 1}{sup −3} Raman modes, with the A{sub 1}{sup −1} and A{sub 1}{sup −2} modes gradually merging together, indicating the merge of the orthorhombic phase. Despite the antiferromagnetic nature of bulk BiFeO{sub 3}, the NBFSO nanopowders obtained displayed a ferromagnetic hysteresis loop, with coercivities of 0.08 T and remanent magnetizations of 0.65–4.05 Am{sup 2}/kg when measured at room temperature. The increasing and uncompensated spins at the surface of nanoparticles and the canted internal spin by the tilt of FeO{sub 6} octahedral units and the structure transition appear to be the main reason for observed this ferromagnetic behavior.

  13. The study of electromagnetic wave propagation in photonic crystals via planewave based transfer (scattering) matrix method with active gain material applications

    Science.gov (United States)

    Li, Ming

    In this dissertation, a set of numerical simulation tools are developed under previous work to efficiently and accurately study one-dimensional (1D), two-dimensional (2D), 2D slab and three-dimensional (3D) photonic crystal structures and their defects effects by means of spectrum (transmission, reflection, absorption), band structure (dispersion relation), and electric and/or magnetic fields distribution (mode profiles). Further more, the lasing property and spontaneous emission behaviors are studied when active gain materials are presented in the photonic crystal structures. First, the planewave based transfer (scattering) matrix method (TMM) is described in every detail along with a brief review of photonic crystal history (Chapter 1 and 2). As a frequency domain method, TMM has the following major advantages over other numerical methods: (1) the planewave basis makes Maxwell's Equations a linear algebra problem and there are mature numerical package to solve linear algebra problem such as Lapack and Scalapack (for parallel computation). (2) Transfer (scattering) matrix method make 3D problem into 2D slices and link all slices together via the scattering matrix (S matrix) which reduces computation time and memory usage dramatically and makes 3D real photonic crystal devices design possible; and this also makes the simulated domain no length limitation along the propagation direction (ideal for waveguide simulation). (3) It is a frequency domain method and calculation results are all for steady state, without the influences of finite time span convolution effects and/or transient effects. (4) TMM can treat dispersive material (such as metal at visible light) naturally without introducing any additional computation; and meanwhile TMM can also deal with anisotropic material and magnetic material (such as perfectly matched layer) naturally from its algorithms. (5) Extension of TMM to deal with active gain material can be done through an iteration procedure with gain

  14. Growth, Properties, and Theoretical Analysis of M2LiVO4 (M = Rb, Cs) Crystals: Two Potential Mid-Infrared Nonlinear Optical Materials.

    Science.gov (United States)

    Han, Guopeng; Wang, Ying; Su, Xin; Yang, Zhihua; Pan, Shilie

    2017-05-15

    Mid-Infrared nonlinear optical (Mid-IR NLO) crystals with excellent performances play a particularly important role for applications in areas such as telecommunications, laser guidance, and explosives detection. However, the design and growth of high performance Mid-IR NLO crystals with large NLO efficiency and high laser-damage threshold (LDT) still face numerous fundamental challenge. In this study, two potential Mid-IR NLO materials, Rb2LiVO4 (RLVO) and Cs2LiVO4 (CLVO) with noncentrosymmetric structures (Orthorhombic, Cmc21) were synthesized by high-temperature solution method. Thermal analysis and powder X-ray diffraction demonstrate that RLVO and CLVO melt congruently. Centimeter sized crystals of CLVO have been grown by the top-seeded solution growth method. RLVO and CLVO exhibit strong second harmonic generation (SHG) effects (about 4 and 5 times that of KH2PO4, respectively) with a phase-matching behavior at 1.064 μm, and a wide transparency range (0.33-6.0 μm for CLVO). More importantly, RLVO and CLVO possess a high LDT value (~28 × AgGaS2). In addition, the density functional theory (DFT) and dipole moments studies indicate that the VO4 anionic groups have a dominant contribution to the SHG effects in RLVO and CLVO. These results suggest that the title compounds are promising NLO candidate crystals applied in the Mid-IR region.

  15. Low Temperature Synthesis and Characterization of AlScMo3O12

    Directory of Open Access Journals (Sweden)

    Rebecca Truitt

    2015-02-01

    Full Text Available Recent interest in low and negative thermal expansion materials has led to significant research on compounds that exhibit this property, much of which has targeted the A2M3O12 family (A = trivalent cation, M = Mo, W. The expansion and phase transition behavior in this family can be tuned through the choice of the metals incorporated into the structure. An undesired phase transition to a monoclinic structure with large positive expansion can be suppressed in some solid solutions by substituting the A-site by a mixture of two cations. One such material, AlScMo3O12, was successfully synthesized using non-hydrolytic sol-gel chemistry. Depending on the reaction conditions, phase separation into Al2Mo3O12 and Sc2Mo3O12 or single-phase AlScMo3O12 could be obtained. Optimized conditions for the reproducible synthesis of stoichiometric, homogeneous AlScMo3O12 were established. High resolution synchrotron diffraction experiments were carried out to confirm whether samples were homogeneous and to estimate the Al:Sc ratio through Rietveld refinement and Vegard’s law. Single-phase samples were found to adopt the orthorhombic Sc2W3O12 structure at 100 to 460 K. In contrast to all previously-reported A2M3O12 compositions, AlScMo3O12 exhibited positive thermal expansion along all unit cell axes instead of contraction along one or two axes, with expansion coefficients (200–460 K of αa = 1.7 × 10−6 K−1, αb = 6.2 × 10−6 K−1, αc = 2.9 × 10−6 K−1 and αV = 10.8 × 10−6 K−1, respectively.

  16. Effect of Severe Plastic Deformation on Structure and Properties of Al-Sc-Ta and Al-Sc-Ti Alloys.

    Science.gov (United States)

    Berezina, Alla; Monastyrska, Tetiana; Davydenko, Olexandr; Molebny, Oleh; Polishchuk, Sergey

    2017-12-01

    The comparative analysis of the effect of monotonous and non-monotonous severe plastic deformations (SPD) on the structure and properties of aluminum alloys has been carried out. Conventional hydrostatic extrusion (HE) with a constant deformation direction and equal-channel angular hydroextrusion (ECAH) with an abrupt change in the deformation direction were chosen for the cases of monotonous and non-monotonous SPD, respectively. Model cast hypoeutectic Al-0.3%Sc alloys and hypereutectic Al-0.6%Sc alloys with Ta and Ti additives were chosen for studying. It was demonstrated that SPD of the alloys resulted in the segregation of the material into active and inactive zones which formed a banded structure. The active zones were shown to be bands of localized plastic deformation. The distance between zones was found to be independent of the accumulated strain degree and was in the range of 0.6-1 μm. Dynamic recrystallization in the active zones was observed using TEM. The dynamic recrystallization was accompanied by the formation of disclinations, deformation bands, low-angle, and high-angle boundaries, i.e., rotational deformation modes developed. The dynamic recrystallization was more intense during the non-monotonous deformation as compared with the monotonous one, which was confirmed by the reduction of texture degree in the materials after ECAH.

  17. Precipitation hardening in ternary alloys of the Al-Sc-Cu and Al-Sc-Si systems

    Energy Technology Data Exchange (ETDEWEB)

    Kharakterova, M.L.; Eskin, D.G.; Toropova, L.S. (Russian Academy of Sciences, Moscow (Russian Federation). A.A. Baikov Inst. of Metallurgy)

    1994-07-01

    The processes of precipitation hardening in cast ternary alloys of the Al-Sc-Cu and Al-Sc-Si systems were studied in the temperature range of aging from 100 to 450 C and at exposures to 200 h. It was shown that the CuAl[sub 2] and ScAl[sub 3] phases were involved in the process of aging in ternary Al-Sc-Cu alloys, and the Si and V (AlSiSc) phases, in ternary Al-Sc-Si alloys with excess silicon in a supersaturated solid solution. The V phase was for the first time revealed as the hardening phase in aluminum alloys.

  18. An analytical model for the determination of crystallite size and crystal lattice microstrain distributions in nanocrystalline materials from the variance of the X-ray diffraction peaks

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Bajo, F. [Universidad de Extremadura, Departamento de Fisica Aplicada, Badajoz (Spain); Ortiz, A.L. [Universidad de Extremadura, Departamento de Ingenieria Mecanica, Energetica y de los Materiales, Badajoz (Spain); Cumbrera, F.L. [Universidad de Extremadura, Departamento de Fisica, Badajoz (Spain)

    2009-01-15

    An analytical model for the determination of crystallite size and crystal lattice microstrain distributions in nanocrystalline (nc) materials by X-ray diffractometry (XRD) is presented. It entails generalizing the variance method to establish analytically the connection between the variance coefficients of the physically broadened XRD peaks and the characteristic parameters of explicit distributions of crystallite sizes and crystal lattice microstrains, which results in a more detailed characterization of the nc-materials. The proposed model is generic in nature and has the potential to be used under the assumption of different mathematical functions for the two distributions, which suggests that it may have an important role to play in the characterization of nc-materials. Nevertheless, the specialization to the case of nc-materials with log-normal crystallite size distribution and three typical types of lattice microstrains is used as an illustration and to formulate explicit analytical expressions of interest. Finally, the usefulness of the proposed model is demonstrated on standard XRD profiles. (orig.)

  19. Crystal growth by Bridgman and Czochralski method of the ferromagnetic quantum critical material YbNi4P2

    Science.gov (United States)

    Kliemt, K.; Krellner, C.

    2016-09-01

    The tetragonal YbNi4P2 is one of the rare examples of compounds that allow the investigation of a ferromagnetic quantum critical point. We report in detail on two different methods which have been used to grow YbNi4P2 single crystals from a self-flux. The first, a modified Bridgman method, using a closed crucible system yields needle-shaped single crystals oriented along the [001]-direction. The second method, the Czochralski growth from a levitating melt, yields large single crystals which can be cut in any desired orientation. With this crucible-free method, samples without flux inclusions and a resistivity ratio at 1.8 K of RR1.8K = 17 have been grown.

  20. LHCb Data Replication During SC3

    CERN Multimedia

    Smith, A

    2006-01-01

    LHCb's participation in LCG's Service Challenge 3 involves testing the bulk data transfer infrastructure developed to allow high bandwidth distribution of data across the grid in accordance with the computing model. To enable reliable bulk replication of data, LHCb's DIRAC system has been integrated with gLite's File Transfer Service middleware component to make use of dedicated network links between LHCb computing centres. DIRAC's Data Management tools previously allowed the replication, registration and deletion of files on the grid. For SC3 supplementary functionality has been added to allow bulk replication of data (using FTS) and efficient mass registration to the LFC replica catalog.Provisional performance results have shown that the system developed can meet the expected data replication rate required by the computing model in 2007. This paper details the experience and results of integration and utilisation of DIRAC with the SC3 transfer machinery.

  1. Reduced-Latency SC Polar Decoder Architectures

    CERN Document Server

    Zhang, Chuan; Parhi, Keshab K

    2011-01-01

    Polar codes have become one of the most favorable capacity achieving error correction codes (ECC) along with their simple encoding method. However, among the very few prior successive cancellation (SC) polar decoder designs, the required long code length makes the decoding latency high. In this paper, conventional decoding algorithm is transformed with look-ahead techniques. This reduces the decoding latency by 50%. With pipelining and parallel processing schemes, a parallel SC polar decoder is proposed. Sub-structure sharing approach is employed to design the merged processing element (PE). Moreover, inspired by the real FFT architecture, this paper presents a novel input generating circuit (ICG) block that can generate additional input signals for merged PEs on-the-fly. Gate-level analysis has demonstrated that the proposed design shows advantages of 50% decoding latency and twice throughput over the conventional one with similar hardware cost.

  2. Single chain Fab (scFab fragment

    Directory of Open Access Journals (Sweden)

    Brenneis Mariam

    2007-03-01

    Full Text Available Abstract Background The connection of the variable part of the heavy chain (VH and and the variable part of the light chain (VL by a peptide linker to form a consecutive polypeptide chain (single chain antibody, scFv was a breakthrough for the functional production of antibody fragments in Escherichia coli. Being double the size of fragment variable (Fv fragments and requiring assembly of two independent polypeptide chains, functional Fab fragments are usually produced with significantly lower yields in E. coli. An antibody design combining stability and assay compatibility of the fragment antigen binding (Fab with high level bacterial expression of single chain Fv fragments would be desirable. The desired antibody fragment should be both suitable for expression as soluble antibody in E. coli and antibody phage display. Results Here, we demonstrate that the introduction of a polypeptide linker between the fragment difficult (Fd and the light chain (LC, resulting in the formation of a single chain Fab fragment (scFab, can lead to improved production of functional molecules. We tested the impact of various linker designs and modifications of the constant regions on both phage display efficiency and the yield of soluble antibody fragments. A scFab variant without cysteins (scFabΔC connecting the constant part 1 of the heavy chain (CH1 and the constant part of the light chain (CL were best suited for phage display and production of soluble antibody fragments. Beside the expression system E. coli, the new antibody format was also expressed in Pichia pastoris. Monovalent and divalent fragments (DiFabodies as well as multimers were characterised. Conclusion A new antibody design offers the generation of bivalent Fab derivates for antibody phage display and production of soluble antibody fragments. This antibody format is of particular value for high throughput proteome binder generation projects, due to the avidity effect and the possible use of

  3. The Study of Electromagnetic Wave Propogation in Photonic Crystals Via Planewave Based Transfer (Scattering) Matrix Method with Active Gain Material Applications

    Energy Technology Data Exchange (ETDEWEB)

    LI, Ming [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    In this dissertation, a set of numerical simulation tools are developed under previous work to efficiently and accurately study one-dimensional (1D), two-dimensional(2D), 2D slab and three-dimensional (3D) photonic crystal structures and their defects effects by means of spectrum (transmission, reflection, absorption), band structure (dispersion relation), and electric and/or magnetic fields distribution (mode profiles). Furthermore, the lasing property and spontaneous emission behaviors are studied when active gain materials are presented in the photonic crystal structures. Various physical properties such as resonant cavity quality factor, waveguide loss, propagation group velocity of electromagnetic wave and light-current curve (for lasing devices) can be obtained from the developed software package.

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

    Science.gov (United States)

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

    2013-12-01

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

  5. The SC gets ready for visitors

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    Hall 300, which houses the Synchrocyclotron (SC), CERN’s first accelerator, is getting ready to host a brand-new exhibition. The site will be one of the stops on the new visit itineraries that will be inaugurated for the 2013 CERN Open Day.   The Synchrocyclotron through the years. Just as it did in the late 1950s, when the accelerator was first installed, the gigantic red structure of the Synchrocyclotron's magnet occupies a large part of the 300-square-metre hall. “We have completed the first phase of the project that will give the SC a new lease of life,” says Marco Silari, the project leader and a member of CERN’s Radiation Protection Group. “We have removed all the equipment that was not an integral part of the accelerator. The hall is now ready for the civil-engineering work that will precede the installation of the exhibition.” The SC was witness to a big part of the history of CERN. The accelerator produced ...

  6. A crystal chemistry approach for high-power ytterbium doped solid-state lasers: diffusion-bonded crystals and new crystalline hosts; Relations structures-proprietes dans les lasers solides de puissance a l'ytterbium: elaboration et caracterisation de nouveaux materiaux et de cristaux composites soudes par diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Gaume, R

    2002-11-15

    This work deals with ytterbium based crystals for high-power laser applications. In particular, we focus our interest in reducing crystal heating and its consequences during laser operation following two different ways. First, we review the specific properties of ytterbium doped solid-state lasers in order to define a figure-of-merit which gives the evaluation of laser performances, thermo-mechanical and thermo-optical properties. Bearing in mind this analysis, we propose a set of theoretical tools, based on the crystallographic structure of the crystal and its chemical composition, to predict thermo-mechanical and optical potentials. This approach, used for the seek of new Yb{sup 3+}-doped materials for high-power laser applications, shows that simple oxides containing rare-earths are favorable. Therefore, the spectroscopic properties of six new materials Yb{sup 3+}:GdVO{sub 4}, Yb{sup 3+}:GdAlO{sub 3}, Yb{sup 3+}:Gd{sub 2}O{sub 3}, Yb{sup 3+}:Sc{sub 2}SiO{sub 5}, Yb{sup 3+}:CaSc{sub 2}O{sub 4} and Yb{sup 3+}:SrSc{sub 2}O{sub 4} are described. The second aspect developed in this work deals with thermal properties enhancement of already well characterized laser materials. Two different ways are explored: a) elaboration by diffusion bonding of end-caps lasers with undoped crystals (composite crystals). Thus, different composites were obtained and a fairly lowering of thermal lensing effect was observed during laser operation. b) strengthening of crystalline structures by ionic substitution of one of its constituents. We demonstrate how crystal growth ability can be improved by a cationic substitution in the case of Yb{sup 3+}:BOYS, a largely-tunable laser material which is of great interest for femtosecond pulses generation. (author)

  7. High performance AlScN thin film based surface acoustic wave devices with large electromechanical coupling coefficient

    Science.gov (United States)

    Wang, Wenbo; Mayrhofer, Patrick M.; He, Xingli; Gillinger, Manuel; Ye, Zhi; Wang, Xiaozhi; Bittner, Achim; Schmid, Ulrich; Luo, J. K.

    2014-09-01

    AlN and AlScN thin films with 27% scandium (Sc) were synthesized by DC magnetron sputtering deposition and used to fabricate surface acoustic wave (SAW) devices. Compared with AlN-based devices, the AlScN SAW devices exhibit much better transmission properties. Scandium doping results in electromechanical coupling coefficient, K2, in the range of 2.0% ˜ 2.2% for a wide normalized thickness range, more than a 300% increase compared to that of AlN-based SAW devices, thus demonstrating the potential applications of AlScN in high frequency resonators, sensors, and high efficiency energy harvesting devices. The coupling coefficients of the present AlScN based SAW devices are much higher than that of the theoretical calculation based on some assumptions for AlScN piezoelectric material properties, implying there is a need for in-depth investigations on the material properties of AlScN.

  8. A United Effort for Crystal Growth, Neutron Scattering, and X-ray Scattering Studies of Novel Correlated Electron Materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young S. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2015-02-12

    The research accomplishments during the award involved experimental studies of correlated electron systems and quantum magnetism. The techniques of crystal growth, neutron scattering, x-ray scattering, and thermodynamic & transport measurements were employed, and graduate students and postdoctoral research associates were trained in these techniques.

  9. Far infrared transmittance of Sc2@C84 and Er2@C82

    NARCIS (Netherlands)

    Grannan, S.M.; Birmingham, J.T.; Richards, P.L.; Bethune, D.S.; Vries, M.S. de; Loosdrecht, P.H.M. van; Dorn, H.C.; Burbank, P.; Bailey, J.; Stevenson, S.

    1997-01-01

    We have measured the far infrared transmittance of Sc2@C84 and Er2@C82 at 1.5 K between 30 and 200 cm-1. Both materials are observed to have a large primary absorption feature centered at 95 cm-1 with a width of approximately 50 cm-1, as well as a number of secondary absorption features which are di

  10. Growth of dopamine crystals

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Vidya, E-mail: vidya.patil@ruparel.edu; Patki, Mugdha, E-mail: mugdha.patki@ruparel.edu [D. G. Ruparel College, Senapati Bapat Marg, Mahim, Mumbai – 400 016 (India)

    2016-05-06

    Many nonlinear optical (NLO) crystals have been identified as potential candidates in optical and electro-optical devices. Use of NLO organic crystals is expected in photonic applications. Hence organic nonlinear optical materials have been intensely investigated due to their potentially high nonlinearities, and rapid response in electro-optic effect compared to inorganic NLO materials. There are many methods to grow organic crystals such as vapor growth method, melt growth method and solution growth method. Out of these methods, solution growth method is useful in providing constraint free crystal. Single crystals of Dopamine have been grown by evaporating the solvents from aqueous solution. Crystals obtained were of the size of orders of mm. The crystal structure of dopamine was determined using XRD technique. Images of crystals were obtained using FEG SEM Quanta Series under high vacuum and low KV.

  11. Growth of dopamine crystals

    Science.gov (United States)

    Patil, Vidya; Patki, Mugdha

    2016-05-01

    Many nonlinear optical (NLO) crystals have been identified as potential candidates in optical and electro-optical devices. Use of NLO organic crystals is expected in photonic applications. Hence organic nonlinear optical materials have been intensely investigated due to their potentially high nonlinearities, and rapid response in electro-optic effect compared to inorganic NLO materials. There are many methods to grow organic crystals such as vapor growth method, melt growth method and solution growth method. Out of these methods, solution growth method is useful in providing constraint free crystal. Single crystals of Dopamine have been grown by evaporating the solvents from aqueous solution. Crystals obtained were of the size of orders of mm. The crystal structure of dopamine was determined using XRD technique. Images of crystals were obtained using FEG SEM Quanta Series under high vacuum and low KV.

  12. What did Erwin mean? The physics of information from the materials genomics of aperiodic crystals and water to molecular information catalysts and life.

    Science.gov (United States)

    Varn, D P; Crutchfield, J P

    2016-03-13

    Erwin Schrödinger famously and presciently ascribed the vehicle transmitting the hereditary information underlying life to an 'aperiodic crystal'. We compare and contrast this, only later discovered to be stored in the linear biomolecule DNA, with the information-bearing, layered quasi-one-dimensional materials investigated by the emerging field of chaotic crystallography. Despite differences in functionality, the same information measures capture structure and novelty in both, suggesting an intimate coherence between the information character of biotic and abiotic matter-a broadly applicable physics of information. We review layered solids and consider three examples of how information- and computation-theoretic techniques are being applied to understand their structure. In particular, (i) we review recent efforts to apply new kinds of information measures to quantify disordered crystals; (ii) we discuss the structure of ice I in information-theoretic terms; and (iii) we recount recent investigations into the structure of tris(bicyclo[2.1.1]hexeno)benzene, showing how an information-theoretic analysis yields additional insight into its structure. We then illustrate a new Second Law of Thermodynamics that describes information processing in active low-dimensional materials, reviewing Maxwell's Demon and a new class of molecular devices that act as information catalysts. Lastly, we conclude by speculating on how these ideas from informational materials science may impact biology.

  13. Atomic structure and phason modes of the Sc-Zn icosahedral quasicrystal.

    Science.gov (United States)

    Yamada, Tsunetomo; Takakura, Hiroyuki; Euchner, Holger; Pay Gómez, Cesar; Bosak, Alexei; Fertey, Pierre; de Boissieu, Marc

    2016-07-01

    The detailed atomic structure of the binary icosahedral (i) ScZn7.33 quasicrystal has been investigated by means of high-resolution synchrotron single-crystal X-ray diffraction and absolute scale measurements of diffuse scattering. The average atomic structure has been solved using the measured Bragg intensity data based on a six-dimensional model that is isostructural to the i-YbCd5.7 one. The structure is described with a quasiperiodic packing of large Tsai-type rhombic triacontahedron clusters and double Friauf polyhedra (DFP), both resulting from a close-packing of a large (Sc) and a small (Zn) atom. The difference in chemical composition between i-ScZn7.33 and i-YbCd5.7 was found to lie in the icosahedron shell and the DFP where in i-ScZn7.33 chemical disorder occurs on the large atom sites, which induces a significant distortion to the structure units. The intensity in reciprocal space displays a substantial amount of diffuse scattering with anisotropic distribution, located around the strong Bragg peaks, that can be fully interpreted as resulting from phason fluctuations, with a ratio of the phason elastic constants K 2/K 1 = -0.53, i.e. close to a threefold instability limit. This induces a relatively large perpendicular (or phason) Debye-Waller factor, which explains the vanishing of 'high-Q perp' reflections.

  14. Anomalous ionic conductivity of Sc sub 2 (WO sub 4) sub 3 mediated by structural changes at high pressures and temperatures

    CERN Document Server

    Secco, R A; Imanaka, N; Adachi, G

    2002-01-01

    The ionic conductivity of Sc sub 2 (WO sub 4) sub 3 at 400 deg. C shows a normal decrease with increase in pressure up to 2.9 GPa but then increases anomalously at pressures up to 4.3 GPa. Synchrotron in situ x-ray diffraction results show that Sc sub 2 (WO sub 4) sub 3 undergoes pressure-induced amorphization at pressures coincident with the reversal in conductivity behaviour. The loss of crystal structure at high pressure may be associated with the property of negative thermal expansion in Sc sub 2 (WO sub 4) sub 3.

  15. Analysis of magneto-optical properties for three-dimensional photonic crystals in high-symmetry arrangement doped by metamaterials and uniaxial materials

    Science.gov (United States)

    Yu, Bing; Li, Heming; Wang, Shenyun; Wan, Fayu; Ge, Junxiang

    2016-11-01

    In this paper, we use a modified plane wave expansion (PWE) method to investigate the properties of photonic band gaps (PBGs) for the extraordinary mode in the three-dimensional (3D) photonic crystals (PCs) which are composed of the anisotropic dielectric (the uniaxial materials) spheres immersed in the homogeneous metamaterials (epsilon-negative materials) background with high-symmetry (body-centered-cubic) lattices, as the magneto-optical Voigt effects are considered. The equations for calculating the PBGs in the first irreducible Brillouin zone are theoretically derived. It is numerically illustrated that the anisotropic PBGs and two flattened band regions can be achieved. The influences of the ordinary-refractive index, extraordinary-refractive index, filling factor of dielectric spheres, electronic plasma frequency and cyclotron frequency on the magneto-optical properties of such 3D PCs also are studied in detail, respectively, and some corresponding physical explanations are given. The numerical results demonstrate that the anisotropy can open partial band gaps in the proposed PCs, and the complete PBGs can be obtained compared with the conventional PCs only containing the isotropic material with similar structures. The bandwidths of PBGs can be tuned by introducing the epsilon-negative materials into such PCs containing the uniaxial materials. The anisotropic PBGs can be manipulated by the parameters as mentioned above. As the proposed PCs with high-symmetry lattices, the complete PBGs can be obtained by introducing the uniaxial materials.

  16. Materials for advanced rocket engine turbopump turbine blades

    Science.gov (United States)

    Chandler, W. T.

    1985-01-01

    A study program was conducted to identify those materials that will provide the greatest benefits as turbine blades for advanced liquid propellant rocket engine turbines and to prepare technology plans for the development of those materials for use in the 1990 through 1995 period. The candidate materials were selected from six classes of materials: single-crystal (SC) superalloys, oxide dispersion-strengthened (ODS) superalloys, rapid solidification processed (RSP) superalloys, directionally solidified eutectic (DSE) superalloys, fiber-reinforced superalloy (FRS) composites, and ceramics. Properties of materials from the six classes were compiled and evaluated and property improvements were projected approximately 5 years into the future for advanced versions of materials in each of the six classes.

  17. Structure and hydrogen storage properties of the hexagonal Laves phase Sc(Al{sub 1-x}Ni{sub x}){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sahlberg, Martin, E-mail: Martin.sahlberg@kemi.uu.se [Department of Chemistry, The Angstroem Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala (Sweden); Angstroem, Jonas, E-mail: jonas.angstrom@kemi.uu.se [Department of Chemistry, The Angstroem Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala (Sweden); Zlotea, Claudia, E-mail: claudia.zlotea@icmpe.cnrs.fr [Chimie Metallurgique des Terres Rares, Institut de Chimie et des Materiaux de Paris Est, UMR 7182, CNRS, 2-8 rue Henri Dunant, 94320 Thiais Cedex (France); Beran, Premysl, E-mail: pberan@ujf.cas.cz [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 25068 Rez (Czech Republic); Latroche, Michel, E-mail: michel.latroche@glvt-cnrs.fr [Chimie Metallurgique des Terres Rares, Institut de Chimie et des Materiaux de Paris Est, UMR 7182, CNRS, 2-8 rue Henri Dunant, 94320 Thiais Cedex (France); Pay Gomez, Cesar, E-mail: Cesar.paygomez@kemi.uu.se [Department of Chemistry, The Angstroem Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala (Sweden)

    2012-12-15

    The crystal structures of hydrogenated and unhydrogenated Sc(Al{sub 1-x}Ni{sub x}){sub 2} Laves phases have been studied by combining several diffraction techniques and it is shown that hydrogen is situated interstitially in the A{sub 2}B{sub 2}-sites, which have the maximum number of scandium neighbours. The hydrogen absorption/desorption behaviour has also been investigated. It is shown that a solid solution of hydrogen forms in the mother compound. The hydrogen storage capacity exceeds 1.7 H/f.u. at 374 K, and the activation energy of hydrogen desorption was determined to 4.6 kJ/mol H{sub 2}. It is shown that these compounds share the same local coordination as Frank-Kasper-type approximants and quasicrystals, which opens up the possibility of finding many new hydride phases with these types of crystal structures. - Graphical abstract: The structure of ScNiAlDx, Sc atoms are shown in purple and Ni/Al atoms in blue and the iso-surfaces of deuterium in yellow. Revealed from refinements of neutron powder diffraction data. Highlights: Black-Right-Pointing-Pointer The crystal structure of ScNiAl and ScNiAlDx is reported. Black-Right-Pointing-Pointer We show the hydrogen storage properties of Sc(Al{sub 1-x}Ni{sub x}){sub 2}. Black-Right-Pointing-Pointer We discuss the possibility to store hydrogen in quasicrystals.

  18. Photoluminescence of CdTe Crystals Grown by Physical-Vapor Transport

    Science.gov (United States)

    Palosz, W.; Grasza, K.; Boyd, P. R.; Cui, Y.; Wright, G.; Roy, U. N.; Burger, A.

    2003-01-01

    High-quality CdTe crystals with resistivities higher than 10(exp 8) omega cm were grown by the physical-vapor transport (PVT) technique. Indium, aluminum, and the transition-metal scandium were introduced at the nominal level of about 6 ppm to the source material. Low-temperature photoluminescence (PL) has been employed to identify the origins of PL emissions of the crystals. The emission peaks at 1.584 eV and 1.581 eV were found only in the In-doped crystal. The result suggests that the luminescence line at 1.584 eV is associated with Cd-vacancy/In complex. The intensity of the broadband centered at 1.43 eV decreases strongly with introduction of Sc.

  19. Photoluminescence of CdTe Crystals Grown by Physical Vapor Transport

    Science.gov (United States)

    Curreri, Peter A. (Technical Monitor); Palosz, W.; Grasza, K.; Boyd, P. R.; Cui, Y.; Wright, G.; Roy, U. N.; Burger, A.

    2002-01-01

    High quality CdTe crystals with resistivities higher than 10(exp 8) omega cm were grown by the physical vapor transport technique. Indium, Aluminum, and the transition metal Scandium were introduced at the nominal level of about 6 ppm to the source material. Low-temperature photoluminescence (PL) has been employed to identify the origins of PL emissions of the crystals. The emission peaks at 1.584 eV and 1.581 eV were found only in the In-doped crystal. The result suggests that the luminescence line at 1.584 eV is associated with Cd-vacancy/indium complex. The intensity of the broadband centered at 1.43 eV decreases strongly with introduction of Sc.

  20. Magnesium sulfate salts and historic building materials: experimental simulation of limestone flaking by relative humidity cycling and crystallization of salts

    Directory of Open Access Journals (Sweden)

    Pinchin, S.

    2008-06-01

    Full Text Available Magnesium sulfate salts often result from the combination of incompatible construction materials, such as stone or mortar with high magnesium content and sulfates from adjacent mortars or polluted air. When combined with a source of moisture, these materials react to form soluble salts, often leading to significant damage by flaking of the stone, as the magnesium sulfate responds to fluctuating environmental conditions. Several laboratory experiments were performed to reproduce surface flaking on different types of limestone from Spain and the UK to evaluate the effects of humidity cycling on the damage of stone by salt crystallization. The two salt solutions used for the experiments were a single salt of magnesium sulfate and a mixture of magnesium sulfate, calcium sulfate and sodium chloride, a typical salt mixture found in damaged stone at the site of Howden Minster (UK. A climate chamber with precise and programmable temperature and humidity control was used to test the hypothesis that salt damage in the stone can be readily caused by humidity fluctuations. Damage was monitored using Linear Variable Differential Transformer (LVDT, which measure transducers displacement by dimensional change on the order of microns. In addition, Ion Chromatography, Environmental Scanning Electron Microscopy with energy dispersive X-ray spectroscopy (ESEM-EDX and X-ray Diffraction analyses (XRD were also carried out to analyze salt behavior. Damage by flaking took place in two types of magnesian limestone cubes impregnated with the salt mixture, from Cadeby quarry and York Minster, apparently by deliquescent salts of low equilibrium relative humidity (RHeq, while the rest of the samples developed a salt crust over the surface, but no damage was observed in the stone. It is important to verify hypotheses developed from field observations with laboratory experiments. By combining both field and laboratory data, a clearer understanding the different mechanisms of

  1. Multiscale Modeling and Computation of Liquid Crystal Polymers, Polymer Blends, and Polymer Nanocomposites: Investigation of Rheology and Material Properties

    Science.gov (United States)

    2008-04-15

    Multiscale kinetic theories for flows of biaxial liquid crystal polymers Given the rising interests in the modeling of nanofluids of biaxial constituents...Newtonian Fluid Mechanics, 2006, 128(1): 44-61. 4. M. G. Forest, R. Zhou, and Q. Wang, Nano-rod suspension flows: a 2D Smoluchowski-Navier-Stokes...dynamics for rigid rod & platelet suspensions in strongly coupled coplanar linear flow and magnetic fields II: Kinetic theory, Physics of Fluids, 2006, 18

  2. High figure-of-merit compact phase shifters based on liquid crystal material for 1-10 GHz applications

    Science.gov (United States)

    Cai, Longzhu; Xu, Huan; Li, Jinfeng; Chu, Daping

    2017-01-01

    A liquid crystal (LC) based tunable microstrip line (ML) phase shifter featuring high performance is presented. The experimental results show an electrically tunable differential phase up to 360° at 10 GHz with an overall insertion loss impedance matching structure is applied, and the measured return loss is considerably improved. The FoM and phase tuning property of the fabricated device as optimized are compared with the state-of-art results published recently and show better performance for both of them.

  3. Subwavelength electromagnetic dynamics in stacked complementary plasmonic crystal slabs.

    Science.gov (United States)

    Iwanaga, Masanobu

    2010-07-19

    Resonant electromagnetic fields in stacked complementary plasmonic crystal slabs (sc-PlCSs) are numerically explored in subwavelength dimensions. It is found that the local plasmon resonances in the sc-PlCSs are composite states of locally enhanced electric and magnetic fields. Two sc-PlCSs are analyzed in this paper and it is shown that each sc-PlCS realizes a resonant electromagnetic state suggested by one of Maxwell equations. It is moreover clarified that the local plasmons open efficient paths of Poynting flux, those result in high-contrast polarized transmission.

  4. Conductivity ageing studies on 1M10ScSZ (M4+=Ce, Hf)

    DEFF Research Database (Denmark)

    Omar, Shobit; Bin Najib, Waqas; Bonanos, Nikolaos

    2011-01-01

    The long-term conductivity stability is tested on zirconia based electrolyte materials for solid oxide fuel cell applications. The ageing studies have been performed on the samples of ZrO2 co-doped with 10mol% of Sc2O3 and 1mol% MO2, where M = Ce or Hf (denoted respectively 1Ce10ScSZ and 1Hf10Sc......SZ) in oxidising and reducing atmospheres, at 600°C for 3000h. At 600°C, these compositions show initial conductivity of around 9–12mS∙cm−1 in air. After 3000h of ageing, no phase transitions are observed in any of the samples. For the first 1000h, the degradation rate is higher than in the subsequent 2000h......; thereafter, conductivity degrades linearly with time for all samples. In air, the loss in the conductivity is lower than in reducing conditions. The 1Ce10ScSZ shows the highest degradation rate of 3.8%/1000h in wet H2/N2 after the first 1000h of ageing. A colour change of the 1Ce10ScSZ sample from white...

  5. ScVO4 under non-hydrostatic compression: a new metastable polymorph

    Science.gov (United States)

    Garg, Alka B.; Errandonea, D.; Rodríguez-Hernández, P.; Muñoz, A.

    2017-02-01

    The high-pressure (HP) behaviour of scandium vanadate (ScVO4) is investigated under non-hydrostatic compression. The compound is studied by means of synchrotron-based powder x-ray diffraction (XRD) and optical-absorption techniques. The occurrence of a non-reversible phase transition is detected. The transition is from the zircon structure to the fergusonite-type structure and takes place around 6 GPa with nearly 10% volume discontinuity. XRD measurements on the pressure cycled sample confirm for the first time that the fergusonite-type ScVO4 can be recovered as the metastable phase at ambient conditions. Raman spectroscopic measurements verify the metastable phase to be of a fergusonite-type phase. Theoretical calculations also corroborate the experimental findings. The fergusonite phase is found to be stiffer than the ambient-pressure zircon phase, as indicated by the observed experimental and theoretical bulk moduli. The optical properties and lattice-dynamics calculation of the fergusonite ScVO4 are discussed. At ambient pressure the band gap of the zircon (fergusonite)-type ScVO4 is 2.75 eV (2.3 eV). This fact suggests that the novel metastable polymorph of ScVO4 can have applications in green technologies; for instance, it can be used as photocatalytic material for hydrogen production by water splitting.

  6. Unexpected magnetic behavior in amorphous Co{sub 90}Sc{sub 10} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ghafari, M., E-mail: mohammad.ghafari@kit.edu, E-mail: skamali@utsi.edu; Gleiter, H. [Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094 (China); Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen (Germany); Sakurai, Y.; Itou, M. [Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1 Kouto, Sayo, Sayo, Hyogo (Japan); Peng, G.; Fang, Y. N.; Feng, T. [Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094 (China); Hahn, H. [Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094 (China); Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen (Germany); KIT-TUD Joint Research Laboratory Nanomaterials, Institute of Materials Science, Technische Universität Darmstadt (TUD), Jovanka-Bontschits-Str. 2, 64287 Darmstadt (Germany); Kamali, S., E-mail: mohammad.ghafari@kit.edu, E-mail: skamali@utsi.edu [Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee Space Institute, Tullahoma, Tennessee 37388 (United States)

    2015-09-28

    An amorphous alloy Co{sub 90}Sc{sub 10} has been prepared by rapid quenching from the melt. The results of magnetization measurements show that this alloy has the highest Curie temperature reported for any amorphous transition metal based alloys. Furthermore, for a Co based amorphous alloy, the magnetic moment is remarkably high. Moreover, the alloy exhibits soft magnetic properties. Based on the findings, amorphous Co{sub 90}Sc{sub 10} appears to be an attractive candidate for applications as a soft magnetic material. The temperature dependence of the reduced magnetization can be described by the Bloch power law. The results show that the B coefficient of the amorphous Co{sub 90}Sc{sub 10} alloy, which is a measure of the rigidity of spin waves, exhibits the lowest value observed until now for any amorphous alloy and is comparable to crystalline alloys. It is found that the Sc atoms in the Co{sub 90}Sc{sub 10} alloy lead to an increase of the itinerant spin moment of Co atoms, and, in contrast to this behaviour, to a decrease of the local 3d-electrons of Co.

  7. Crystal growth, vibrational, optical, thermal and theoretical studies of a nonlinear optical material: 2-Methyl 3,5-dinitrobenzoic acid

    Energy Technology Data Exchange (ETDEWEB)

    Sangeetha, K. [Department of Physics, Sri Sarada College for Women, Salem-16 (India); Guru Prasad, L. [Department of Science & Humanities, M. Kumarasamy College of Engineering, Karur (India); Mathammal, R. [Department of Physics, Sri Sarada College for Women, Salem-16 (India)

    2016-11-15

    Single crystals of 2-methyl 3,5-dinitro benzoic acid with reasonable size have been grown by slow evaporation solution growth method using ethanol as solvent. Quantum chemical calculation of 2-methyl 3,5-Dinitro benzoic acid was carried out by using DFT/B3LYP/6-31+G(d,p) method. The powder X-ray diffraction pattern was recorded and indexed. Both the experimental and theoretical vibrational spectrum validates the presence of functional groups. Polarizability, first order hyperpolarizability and the electric dipole moment values have been computed theoretically. The {sup 1}H and {sup 13}C NMR chemical shift of the molecule was calculated and compared with experimental results. TG/DSC analysis has been employed to understand the thermal and physio-chemical stability of the title compound. Frequency conversion property of the crystal was tested by Kurtz and Perry method. Optical absorption behavior of the grown crystal was examined by recording the optical spectrum and band gap energy was also estimated. The calculated HOMO and LUMO energy shows the charge transfer nature of the molecule.

  8. Crystal growth, vibrational, optical, thermal and theoretical studies of a nonlinear optical material: 2-Methyl 3,5-dinitrobenzoic acid

    Science.gov (United States)

    Sangeetha, K.; Guru Prasad, L.; Mathammal, R.

    2016-11-01

    Single crystals of 2-methyl 3,5-dinitro benzoic acid with reasonable size have been grown by slow evaporation solution growth method using ethanol as solvent. Quantum chemical calculation of 2-methyl 3,5-Dinitro benzoic acid was carried out by using DFT/B3LYP/6-31+G(d,p) method. The powder X-ray diffraction pattern was recorded and indexed. Both the experimental and theoretical vibrational spectrum validates the presence of functional groups. Polarizability, first order hyperpolarizability and the electric dipole moment values have been computed theoretically. The 1H and 13C NMR chemical shift of the molecule was calculated and compared with experimental results. TG/DSC analysis has been employed to understand the thermal and physio-chemical stability of the title compound. Frequency conversion property of the crystal was tested by Kurtz and Perry method. Optical absorption behavior of the grown crystal was examined by recording the optical spectrum and band gap energy was also estimated. The calculated HOMO and LUMO energy shows the charge transfer nature of the molecule.

  9. Phononic crystal devices

    Science.gov (United States)

    El-Kady, Ihab F.; Olsson, Roy H.

    2012-01-10

    Phononic crystals that have the ability to modify and control the thermal black body phonon distribution and the phonon component of heat transport in a solid. In particular, the thermal conductivity and heat capacity can be modified by altering the phonon density of states in a phononic crystal. The present invention is directed to phononic crystal devices and materials such as radio frequency (RF) tags powered from ambient heat, dielectrics with extremely low thermal conductivity, thermoelectric materials with a higher ratio of electrical-to-thermal conductivity, materials with phononically engineered heat capacity, phononic crystal waveguides that enable accelerated cooling, and a variety of low temperature application devices.

  10. Macroscopically Oriented Porous Materials with Periodic Ordered Structures: From Zeolites and Metal-Organic Frameworks to Liquid-Crystal-Templated Mesoporous Materials.

    Science.gov (United States)

    Cho, Joonil; Ishida, Yasuhiro

    2017-07-01

    Porous materials with molecular-sized periodic structures, as exemplified by zeolites, metal-organic frameworks, or mesoporous silica, have attracted increasing attention due to their range of applications in storage, sensing, separation, and transformation of small molecules. Although the components of such porous materials have a tendency to pack in unidirectionally oriented periodic structures, such ideal types of packing cannot continue indefinitely, generally ceasing when they reach a micrometer scale. Consequently, most porous materials are composed of multiple randomly oriented domains, and overall behave as isotropic materials from a macroscopic viewpoint. However, if their channels could be unidirectionally oriented over a macroscopic scale, the resultant porous materials might serve as powerful tools for manipulating molecules. Guest molecules captured in macroscopically oriented channels would have their positions and directions well-defined, so that molecular events in the channels would proceed in a highly controlled manner. To realize such an ideal situation, numerous efforts have been made to develop various porous materials with macroscopically oriented channels. An overview of recent studies on the synthesis, properties, and applications of macroscopically oriented porous materials is presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. ViSC Social Competence Program.

    Science.gov (United States)

    Strohmeier, Dagmar; Hoffmann, Christine; Schiller, Eva-Maria; Stefanek, Elisabeth; Spiel, Christiane

    2012-01-01

    The ViSC Social Competence Program has been implemented in Austrian schools within the scope of a national strategy plan, Together Against Violence. The program is a primary preventive program designed for grades 5 to 8. The prevention of aggression and bullying is defined as a school development task, and the initial implementation of the program lasts one school year. The program consists of universal and specific actions that are implemented through in-school teacher training and a class project for students. The program was evaluated with a randomized intervention control group design. Data were collected from teachers and students. Results suggest that the program reduces aggression in schools.

  12. Effect of minor Sc and Zr addition on grain refi nement of as-cast Al-Zn-Mg-Cu alloys

    Directory of Open Access Journals (Sweden)

    He Yongdong

    2009-08-01

    Full Text Available The optical microscopy and scanning electron microscopy as well as energy dispersive spectroscopy were employed to investigate the infl uence of joint addition of Sc and Zr on grain refi nement of Al-Zn-Mg-Cu alloys.Results show that the addition of 0.20% Sc has a little effect on grain refi nement because Sc is mainly dissolved into the matrix and hardly any primary Al3Sc particles are precipitated. The alloy with addition of 0.30% Sc and 0.16% Zr has more equiaxed grains than that of others, giving cast grain sizes as fi ne as 13 μm. This is because the Sc substitutes for Al atom in the Al-Zr crystal cell and forms Al-Sc-Zr unit cell, which grows and becomes Al3(Scx,Zr1-x particle, acting as a nucleus for the formation of α-Al. The addition of 0.04% Ti and 0.008% B makes the grain size drop from 250 μm to 50 μm. Its refi nement effect is less than the 13 μm achieved by the alloy including 0.30% Sc and 0.16% Zr.

  13. Structural and Controllable Thermal Expansion Properties of Sc2-xAlxMo3O12

    Institute of Scientific and Technical Information of China (English)

    WU; Mei-mei; CHEN; Dong-feng

    2013-01-01

    Materials with controllable thermal expansion are the subject of fundamental studies because of the important applications in high-precision optical mirrors,fiber optic systems,and electronic materials.Samples Sc2-xAlxMo3O12(x=0.0,0.3,0.7,1.0,1.3,1.7,and 2.0)were prepared by the solid-state reaction,

  14. Study on the crystallization behaviour and thermal stability of glass-ceramics used as solid oxide fuel cell-sealing materials

    Science.gov (United States)

    Gödeke, Dieter; Dahlmann, Ulf

    Glass ceramics are commonly used as sealing materials for planar solid oxide fuel cells (SOFCs). The major requirements of stack and module builders for these materials are the stability of the coefficient of thermal expansion (CTE), excellent bonding (sticking) behaviour and the absence of volatile ingredients, which can lead to changes of the material properties and the sealing ability. SCHOTT Electronic Packaging has developed special glasses and glass-ceramics for various solid oxide fuel cell designs and operating temperatures. The glass compositions are based on the system MgO-Al 2O 3-BaO-SiO 2-B 2O 3. In this study the evaluation of the developed materials was done by high temperature aging tests for up to 1000 h, high temperature XRD-studies and Rietveld calculations, combined with scanning-electron microscope analysis. Samples of these aged samples were chemically analysed by XRD and wet chemical methods. Results show that after thermal aging of the glasses barium silicates accompanied by barium-magnesium silicates are the major crystalline phases of the glasses. The crystal phases remain stable during high temperature aging tests, indicating a low driving force of material change. The experimental results are compared to phase diagrams by phenomenological and thermochemical considerations.

  15. Identifying Structure-Property Relationships Through DREAM.3D Representative Volume Elements and DAMASK Crystal Plasticity Simulations: An Integrated Computational Materials Engineering Approach

    Science.gov (United States)

    Diehl, Martin; Groeber, Michael; Haase, Christian; Molodov, Dmitri A.; Roters, Franz; Raabe, Dierk

    2017-03-01

    Predicting, understanding, and controlling the mechanical behavior is the most important task when designing structural materials. Modern alloy systems—in which multiple deformation mechanisms, phases, and defects are introduced to overcome the inverse strength-ductility relationship—give raise to multiple possibilities for modifying the deformation behavior, rendering traditional, exclusively experimentally-based alloy development workflows inappropriate. For fast and efficient alloy design, it is therefore desirable to predict the mechanical performance of candidate alloys by simulation studies to replace time- and resource-consuming mechanical tests. Simulation tools suitable for this task need to correctly predict the mechanical behavior in dependence of alloy composition, microstructure, texture, phase fractions, and processing history. Here, an integrated computational materials engineering approach based on the open source software packages DREAM.3D and DAMASK (Düsseldorf Advanced Materials Simulation Kit) that enables such virtual material development is presented. More specific, our approach consists of the following three steps: (1) acquire statistical quantities that describe a microstructure, (2) build a representative volume element based on these quantities employing DREAM.3D, and (3) evaluate the representative volume using a predictive crystal plasticity material model provided by DAMASK. Exemplarily, these steps are here conducted for a high-manganese steel.

  16. Identifying Structure-Property Relationships Through DREAM.3D Representative Volume Elements and DAMASK Crystal Plasticity Simulations: An Integrated Computational Materials Engineering Approach

    Science.gov (United States)

    Diehl, Martin; Groeber, Michael; Haase, Christian; Molodov, Dmitri A.; Roters, Franz; Raabe, Dierk

    2017-05-01

    Predicting, understanding, and controlling the mechanical behavior is the most important task when designing structural materials. Modern alloy systems—in which multiple deformation mechanisms, phases, and defects are introduced to overcome the inverse strength-ductility relationship—give raise to multiple possibilities for modifying the deformation behavior, rendering traditional, exclusively experimentally-based alloy development workflows inappropriate. For fast and efficient alloy design, it is therefore desirable to predict the mechanical performance of candidate alloys by simulation studies to replace time- and resource-consuming mechanical tests. Simulation tools suitable for this task need to correctly predict the mechanical behavior in dependence of alloy composition, microstructure, texture, phase fractions, and processing history. Here, an integrated computational materials engineering approach based on the open source software packages DREAM.3D and DAMASK (Düsseldorf Advanced Materials Simulation Kit) that enables such virtual material development is presented. More specific, our approach consists of the following three steps: (1) acquire statistical quantities that describe a microstructure, (2) build a representative volume element based on these quantities employing DREAM.3D, and (3) evaluate the representative volume using a predictive crystal plasticity material model provided by DAMASK. Exemplarily, these steps are here conducted for a high-manganese steel.

  17. Synthesis, microstructural characterization and optical properties of undoped, V and Sc doped ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Amezaga-Madrid, P.; Antunez-Flores, W.; Ledezma-Sillas, J.E.; Murillo-Ramirez, J.G.; Solis-Canto, O.; Vega-Becerra, O.E.; Martinez-Sanchez, R. [Centro de Investigacion en Materiales Avanzados S.C. and Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes 120, Chihuahua, Chih., C.P. 31109 (Mexico); Miki-Yoshida, M., E-mail: mario.miki@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados S.C. and Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes 120, Chihuahua, Chih., C.P. 31109 (Mexico)

    2011-06-15

    Research highlights: > Undoped, V and Sc doped ZnO thin films by Aerosol Assisted Chemical Vapour Deposition. > Optimum substrate temperatures of 673 K and 623 K for Sc and V doped films. > Around one third of the dopants in solution were deposited into the films. > Crystallite and grain size decreased with the increase of dopant concentration. > Optical band gap increased from 3.29 to 3.32 eV for undoped to 7 Sc/Zn at. %. - Abstract: Many semiconductor oxides (ZnO, TiO{sub 2}, SnO{sub 2}) when doped with a low percentage of non-magnetic (V, Sc) or magnetic 3d (Co, Mn, Ni, Fe) cation behave ferromagnetically. They have attracted a great deal of interest due to the integration of semiconducting and magnetic properties in a material. ZnO is one of the most promising materials to carry out these tasks in view of the fact that it is optically transparent and has n or p type conductivity. Here, we report the synthesis, microstructural characterization and optical properties of undoped, V and Sc doped zinc oxide thin films. ZnO based thin films with additions of V and Sc were deposited by the Aerosol Assisted Chemical Vapour Deposition method. V and Sc were incorporated separately in the precursor solution. The films were uniform, transparent and non-light scattering. The microstructure of the films was characterized by Grazing Incidence X-ray Diffraction, Scanning Electron Microscopy, and Scanning Probe Microscopy. Average grain size and surface rms roughness were estimated by the measurement of Atomic Force Microscopy. The microstructure of doped ZnO thin films depended on the type and amount of dopant material incorporated. The optical properties were determined from specular reflectance and transmittance spectra. Results were analyzed to determine the optical constant and band gap of the films. An increase in the optical band gap with the content of Sc dopant was obtained.

  18. Acute Splenic Sequestration Crisis in a 70-Year-Old Patient With Hemoglobin SC Disease

    Directory of Open Access Journals (Sweden)

    John J. Squiers BSE

    2016-03-01

    Full Text Available A 70-year-old African American female with a past medical history significant for chronic bilateral shoulder pain and reported sickle cell trait presented with acute-onset bilateral thoracolumbar pain radiating to her left arm. Two days after admission, Hematology was consulted for severely worsening microcytic anemia and thrombocytopenia. Examination of the patient’s peripheral blood smear from admission revealed no cell sickling, spherocytes, or schistocytes. Some targeting was noted. A Coombs test was negative. The patient was eventually transferred to the medical intensive care unit in respiratory distress. Hemoglobin electrophoresis confirmed a diagnosis of hemoglobin SC disease. A diagnosis of acute splenic sequestration crisis complicated by acute chest syndrome was crystallized, and red blood cell exchange transfusion was performed. Further research is necessary to fully elucidate the pathophysiology behind acute splenic sequestration crisis, and the role of splenectomy to treat hemoglobin SC disease patients should be better defined.

  19. BOOK REVIEW: Assessing Sc1 for GCSE

    Science.gov (United States)

    Reynolds, H.

    2000-01-01

    It is well known that investigations that `fit' the National Curriculum or examination board criteria are few in number. The fair testing emphasis means that pupils all over the country are finding out what affects the rate of a chemical reaction, the rate of photosynthesis or, in the case of Physics, the resistance of a wire. This book focuses on nine of the most common Sc1 investigations and how to prepare for them, manage and assess them. The author, a GCSE examiner, has turned his expertise into a handbook for improving Sc1 performance in the classroom. He has produced a book that would be extremely useful to both newly qualified teachers and experienced teachers. The first aim of the book, however, is to explain the requirements of Sc1. This is done comprehensively with examples of what the jargon means in practice. By breaking down the elements of planning, obtaining evidence, analysing evidence and evaluating, it is easy to see the subtleties of the mark descriptors. At first glance there seems to be little difference between the type of scientific knowledge needed for planning at level 6 and level 8. However, the level 8 statement specifies `detailed' scientific knowledge and understanding, which would mean a student should use equations from physics or symbolic chemical equations to support their arguments. One of the most useful sections in the book details the marking problems that can arise with some investigations. For example, in an investigation into electromagnets it is difficult for students to provide sufficient relevant scientific theory to satisfy the requirements of planning at level 6. One of the problems with Sc1 is that certain requirements, such as graph plotting, are difficult for many students. This book provides exercises that can be given to students to improve those skills. Each of the nine investigations is covered in great detail. Each investigation begins with an introduction detailing the rationale for choosing it, whether students

  20. Non-centrosymmetric crystals of new N-benzylideneaniline derivatives as potential materials for non-linear optics.

    Science.gov (United States)

    Souza, Talita Evelyn; Rosa, Iara Maria Landre; Legendre, Alexandre Oliveira; Paschoal, Diego; Maia, Lauro J Q; Dos Santos, Hélio F; Matins, Felipe Terra; Doriguetto, Antonio Carlos

    2015-08-01

    Three new N-benzylideneaniline derivatives [p-nitrobenzylidene-p-phenylamineaniline (I), 2,4-dinitrobenzylidene-p-phenylamineaniline (II) and p-dinitrobenzylidene-p-diethylamineaniline (III)] containing electron-push-pull groups have been prepared. They present a planar N-benzylideneaniline core and neighbouring functional atoms, which are related through an efficient intramolecular charge transfer (CT). Two of the derivatives crystallize in non-centrosymmetric space groups, a necessary condition for non-linear optical (NLO) responses. The NLO properties were calculated for the molecular conformations determined by single-crystal X-ray diffraction as well as for the four molecules packed into each corresponding unit cell, using a quantum-chemical method at the cam-B3LYP/NLO-V level of theory. As expected from antiparallel face-to-face stacking through centrosymmetry, the main NLO descriptors - namely, the first hyperpolarizability (βtot) and its projection on the dipole moment direction (βvec) - are almost zero for the tetramer of derivative III. Interestingly, the calculated first hyperpolarizability decreases in the non-centrosymmetric unit-cell content of derivative II when compared to its single molecule, which may be related to its molecular pillaring, similar to that observed in derivative III. On the other hand, a desirable magnification of the NLO properties was found for packed units of derivative I, which may be a consequence of its parallel face-to-tail stacking with the CT vectors of all molecules pointing in the same direction. Moreover, the CT vector of compound I makes an angle of θ = 33.6° with its crystal polar axis, resulting in a higher-order parameter (cos(3)θ = 0.6) compared with the other derivatives. This is in line with the higher macroscopic second-order NLO response predicted for derivative I, βtot = 120.4 × 10(-30) e.s.u.

  1. Synthesis and optical activity of isosorbide chiral derivative containing fluorocarbon group as chiral dopant in liquid crystal materials

    Institute of Scientific and Technical Information of China (English)

    Kong Liang Xie; Yin He Su; Chun Xiang Zhang

    2011-01-01

    Novel isosorbide derivative containing perfluorocarbon group, bi(perfluorooctanesulfonyl)isosorbide ester as chiral dopant in liquid crystal, was synthesized. Chemical structure was characterized by elemental analysis, FT-IR, 1H NMR and 19F NMR. The optical texture of the mixture was observed by polarized optical microscopy (POM). Novel chiral dopant containing perfluorocarbon group had excellent optical activity. Its specific rotation and molar rotation were noticeable higher than those of bi(4-chloromethylbenzenecarbonic)isosorbide ester. The fluorocarbon group improved the molar rotation of chiral compound and did not affect optical rotation direction. The texture of the mixture added isosorbide derivative with fluorocarbon group showed the oily streak texture.

  2. [Spherical crystallization in pharmaceutical technology].

    Science.gov (United States)

    Szabóné, R P; Pintyéné, H K; Kása, P; Erös, I; Hasznosné, N M; Farkas, B

    1998-03-01

    Physical properties of crystals, such as size, crystal size distribution and morphology, may predetermine the usefulness of crystalline materials in many pharmaceutical application. The above properties can be regulated with the crystallization process. The spherical crystals are suitable for direct tablet-making because of their better flowability and compressibility properties. These crystals can be used in the filling of the capsule. In this work, the spherical crystals such as "single crystal", "poly-crystals" and agglomerates with other excipients are collected from the literature and the experimental results of the authors. A close cooperation between chemists and the pharmaceutical technologists can help for doing steps in this field.

  3. Construction of multiform scFv antibodies using linker peptide

    Institute of Scientific and Technical Information of China (English)

    Shihua Wang; Cengjie Zheng; Ying Liu; Huirong Zheng; Zonghua Wang

    2008-01-01

    Multiform single chain variable fragments (acFvs) including different length linker scFvs and bispecific seFv were constructed. The linker lengths of 0, 3, 5, 8, 12, and 15 amino acids between VH and VL of antideoxynivalenol (anti-DON) scFv were used to analyze the affinities of scFvs. The affinity constants of these scFvs increased when the linker was lower than 12 amino acids. The affinity constant would not change when the linker was longer than 12 amino acids. Fusion gene of anti-DON seFv and antizearalenone (anti-ZEN) scFv was also constructed through eormection by a short peptide tinker DNA to express a bispecific scFv. The affinity constants assay showed that the two scFvs of fusion bispecific scFv remained their own affinity compared to their parental scFvs. Competitive direct enzyme linked immunosorbent assay was used to detect DON and ZEN in contaminated wheat (Triticum aestivum L.) samples, and the results indicated that this bispecifie acFv was applicable in DON and ZEN detection. This work confirmed that bispecific scFv could be successfully obtained, and might also have an application in diagnosing fungal infection, and breeding transgertic plants.

  4. Materials characterization

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, N.W.; Nicolet, M.A.

    1986-01-01

    This book presents the papers given at a symposium on the methods used in the chemical analysis of materials. Topics considered at the symposium included emerging techniques for materials microanalysis, scanning electron microscopy, Raman spectroscopy, Auger electron spectroscopy, crystal lattices, computerized tomography using synchrotron radiation, epitaxy, photoconductivity, elastic properties, neutron-induced particle track mapping of elemental distributions, and point defects in crystals.

  5. 热处理材料晶体结构的相变研究%THE TRANSITION RESEARCH OF HEAT TREATMENT MATERIAL CRYSTAL STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    施红娟

    2012-01-01

    金属材料经过热处理过程使材料具有优良的组织和性能,广泛应用于先进科技和日常生活中。金属材料的微观显微组织是研究金属材料组织性能的有效方法。金属材料微观组织的形成是金属材料合金成分在金属晶体晶胞中的溶入析出,金属晶体的晶格结构从体心立方晶格转变成面心立方晶格和密排六方晶格。金属材料不同的热处理过冷转变温度形成不同的微观形态的相结构。金属材料从加热状态冷却到室温,金属材料微观晶格结构的变化我们称之为相变。%metal materials after heat treatment process so that the materials have excellent microstructure and properties widely used in advanced technology and dail life. Metal mate rials microsttucture analysis a effective method to study of metallic materials structure and properties. Metal materials microstructure formation is a procedure of alloy compositions in metal crystal lattice dissolution and procipitation, metal crystal lattice strucrure from a body-centered cublc lattice into dense row of six cubic lattice and face centered cubic lattice. Metallic materials of different heat treatment ocld transformation tempreture form different microscopic porphology of the phase structure. From the high temperature heating to colling room temperature. the metal materials microscopic lattice structure changes we called phase transition. This paper we study of metallic materials the microscopic crstal structure of phase transition proces.

  6. Structural, electrical and magnetic properties of Sc3+ doped Mn-Zn ferrite nanoparticles

    Science.gov (United States)

    Angadi, V. Jagdeesha; Choudhury, Leema; Sadhana, K.; Liu, Hsiang-Lin; Sandhya, R.; Matteppanavar, Shidaling; Rudraswamy, B.; Pattar, Vinayak; Anavekar, R. V.; Praveena, K.

    2017-02-01

    Sc3+ doped Mn0.5Zn0.5ScyFe2-yO4 (y=0.00, 0.01, 0.03 and 0.05) nanoparticles were synthesized by solution combustion method using mixture of fuels were reported for the first time. The mixture of fuels plays an important role in obtaining nano crystalline, single phase present without any heat treatment. X-ray diffraction (XRD) results confirm the formation of the single-phase ferrites which crystallize in cubic spinel structure. The Fourier transform infrared spectra (FTIR) exhibit two prominent bands around 360 cm-1 and 540 cm-1 which are characteristic feature of spinel ferrite. The transmission electron microscope (TEM) micrographs revealed the nanoparticles to be nearly spherical in shape and of fairly uniform size. The room temperature impedance spectra (IS) and vibrating sample magnetometry (VSM) measurements were carried out in order to study the effect of doping (Sc3+) on the characteristic properties of Mn-Zn ferrites. Further, the frequency dependent dielectric constant and dielectric loss were found to decrease with increasing multiple Sc3+ concentration. Nyquist plot in the complex impedance spectra suggest the existence of multiple electrical responses. Magnetic measurements reveals that saturation magnetization (Ms), remnant magnetization (Mr), magnetic moment (ηB) and magnetic particle size (Dm) increase with Sc3+ ion concentration up to x=0.03 and then decrease. The values of spin canting angle (αY-K) and the magnetic particle size (Dm) are found to be in the range of 68-75° and 10-19 nm respectively with Sc3+ concentration. The room temperature Mössbauer spectra were fitted with two sextets corresponding to ions at tetrahedral (A-) and octahedral (B-) sites confirms the spinel lattice. The ferromagnetic resonance (FMR) spectra's has shown that high concentration of scandium doping leads to an increase in dipolar interaction and decrease in super exchange interaction.

  7. Electronic and atomic structures of the Sr3Ir4Sn13 single crystal: A possible charge density wave material

    Science.gov (United States)

    Wang, H.-T.; Srivastava, M. K.; Wu, C.-C.; Hsieh, S.-H.; Wang, Y.-F.; Shao, Y.-C.; Liang, Y.-H.; Du, C.-H.; Chiou, J.-W.; Cheng, C.-M.; Chen, J.-L.; Pao, C.-W.; Lee, J.-F.; Kuo, C. N.; Lue, C. S.; Wu, M.-K.; Pong, W.-F.

    2017-01-01

    X-ray scattering (XRS), x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) spectroscopic techniques were used to study the electronic and atomic structures of the high-quality Sr3Ir4Sn13 (SIS) single crystal below and above the transition temperature (T* ≈ 147 K). The evolution of a series of modulated satellite peaks below the transition temperature in the XRS experiment indicated the formation of a possible charge density wave (CDW) in the (110) plane. The EXAFS phase derivative analysis supports the CDW-like formation by revealing different bond distances [Sn1(2)-Sn2] below and above T* in the (110) plane. XANES spectra at the Ir L3-edge and Sn K-edge demonstrated an increase (decrease) in the unoccupied (occupied) density of Ir 5d-derived states and a nearly constant density of Sn 5p-derived states at temperatures T atomic structures and the CDW-like phase in the SIS single crystal. PMID:28106144

  8. Effect of a Polymercaptan Material on the Electro-Optical Properties of Polymer-Dispersed Liquid Crystal Films

    Directory of Open Access Journals (Sweden)

    Yujian Sun

    2016-12-01

    Full Text Available Polymer-dispersed liquid crystal (PDLC films were prepared by the ultraviolet-light-induced polymerization of photopolymerizable monomers in nematic liquid crystal/chiral dopant/thiol-acrylate reaction monomer composites. The effects of the chiral dopant and crosslinking agents on the electro-optical properties of the PDLC films were systematically investigate. While added the chiral dopant S811 into the PDLC films, the initial off-state transmittance of the films was decreased. It was found that the weight ratio among acrylate monomers, thiol monomer PETMP and the polymercaptan Capcure 3-800 showed great influence on the properties of the fabricated PDLC films because of the existence of competition between thiol-acrylate reaction and acrylate monomer polymerization reaction. While adding polymercaptans curing agent Capcure 3-800 with appropriate concentration into the PDLC system, lower driven voltage and higher contrast ratio were achieved. This made the polymer network and electro-optical properties of the PDLC films easily tunable by the introduction of the thiol monomers.

  9. The right circular polarized waves in the three-dimensional anisotropic dispersive photonic crystals consisting of the magnetized plasma and uniaxial material as the Faraday effects considered

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hai-Feng, E-mail: hanlor@163.com, E-mail: lsb@nuaa.edu.cn [Key Laboratory of Radar Imaging and Microwave Photonics (Nanjing Univ. Aeronaut. Astronaut.), Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Nanjing Artillery Academy, Nanjing 211132 (China); Liu, Shao-Bin, E-mail: hanlor@163.com, E-mail: lsb@nuaa.edu.cn; Tang, Yi-Jun [Key Laboratory of Radar Imaging and Microwave Photonics (Nanjing Univ. Aeronaut. Astronaut.), Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Zhen, Jian-Ping [Nanjing Artillery Academy, Nanjing 211132 (China)

    2014-03-15

    In this paper, the properties of the right circular polarized (RCP) waves in the three-dimensional (3D) dispersive photonic crystals (PCs) consisting of the magnetized plasma and uniaxial material with face-centered-cubic (fcc) lattices are theoretically investigated by the plane wave expansion method, which the homogeneous anisotropic dielectric spheres (the uniaxial material) immersed in the magnetized plasma background, as the Faraday effects of magnetized plasma are considered (the incidence electromagnetic wave vector is parallel to the external magnetic field at any time). The equations for calculating the anisotropic photonic band gaps (PBGs) for the RCP waves in the first irreducible Brillouin zone are theoretically deduced. The anisotropic PBGs and a flatbands region can be obtained. The effects of the ordinary-refractive index, extraordinary-refractive index, anisotropic dielectric filling factor, plasma frequency, and plasma cyclotron frequency (the external magnetic field) on the properties of first two anisotropic PBGs for the RCP waves are investigated in detail, respectively. The numerical results show that the anisotropy can open partial band gaps in fcc lattices at U and W points, and the complete PBGs for the RCP waves can be achieved compared to the conventional 3D dispersive PCs composed of the magnetized plasma and isotropic material. It is also shown that the first two anisotropic PBGs can be tuned by those parameters as mentioned above. Those PBGs can be enlarged by introducing the uniaxial material into such 3D PCs as the Faraday effects are considered.

  10. Protein crystallization with paper

    Science.gov (United States)

    Matsuoka, Miki; Kakinouchi, Keisuke; Adachi, Hiroaki; Maruyama, Mihoko; Sugiyama, Shigeru; Sano, Satoshi; Yoshikawa, Hiroshi Y.; Takahashi, Yoshinori; Yoshimura, Masashi; Matsumura, Hiroyoshi; Murakami, Satoshi; Inoue, Tsuyoshi; Mori, Yusuke; Takano, Kazufumi

    2016-05-01

    We developed a new protein crystallization method that incorporates paper. A small piece of paper, such as facial tissue or KimWipes, was added to a drop of protein solution in the traditional sitting drop vapor diffusion technique, and protein crystals grew by incorporating paper. By this method, we achieved the growth of protein crystals with reducing osmotic shock. Because the technique is very simple and the materials are easy to obtain, this method will come into wide use for protein crystallization. In the future, it could be applied to nanoliter-scale crystallization screening on a paper sheet such as in inkjet printing.

  11. High-performance slow light photonic crystal waveguides with topology optimized or circular-hole based material layouts

    DEFF Research Database (Denmark)

    Wang, Fengwen; Jensen, Jakob Søndergaard; Sigmund, Ole

    2012-01-01

    Photonic crystal waveguides are optimized for modal confinement and loss related to slow light with high group index. A detailed comparison between optimized circular-hole based waveguides and optimized waveguides with free topology is performed. Design robustness with respect to manufacturing...... imperfections is enforced by considering different design realizations generated from under-, standard- and over-etching processes in the optimization procedure. A constraint ensures a certain modal confinement, and loss related to slow light with high group index is indirectly treated by penalizing field...... of 0.48 or above. The comparisons between circular-hole based designs and topology optimized designs illustrate that the former can be efficient for dispersion engineering but that larger improvements are possible if irregular geometries are allowed....

  12. Ultra high-Q photonic crystal nanocavity design: The effect of a low-epsilon slab material

    CERN Document Server

    Bayn, Igal

    2008-01-01

    We analyze the influence of the dielectric constant of the slab on the quality factor (Q) in slab photonic crystal cavities with a minimized vertical losses model. The higher value of Q in high-epsilon cavity is attributed to the lower mode frequency. The Q ratio in a high-epsilon (silicon) vs. low-epsilon (diamond) slab is examined as a function of mode volume (Vm). The mode volume compensation technique is discussed. Finally, diamond cavity design is addressed. The analytical results are compared to 3D FDTD calculations. In a double heterostructure design, a Q=2.6*10^5 is obtained. The highest Q=1.3*10^6 with Vm=1.77*(lambda/n)^3 in a local width modulation design is derived.

  13. Nucleation and crystallization of Ca doped basaltic glass for the production of a glass-ceramic material

    Science.gov (United States)

    Tarrago, Mariona; Royo, Irene; Garcia-Valles, Maite; Martínez, Salvador

    2016-04-01

    Sewage sludge from wastewater treatment plants is a waste with a composition roughly similar to that of a basalt. It may contain potentially toxic elements that can be inertized by vitrification. Using a glass-ceramic process, these elements will be emplaced in newly formed mineral phases. Glass-ceramic production requires an accurate knowledge of the temperatures of nucleation (TN) and crystal growth of the corresponding minerals. This work arises from the study of the addition of ions to a basaltic matrix in order to establish a model of vitrification of sewage sludge. In this case a glass-ceramic is obtained from a glass made with a basalt that has been doped with 16% CaO. Two glasses which underwent different cooling processes have been produced and compared. The first was annealed at 650oC (AG) and the second was quenched (QG). The chemical composition of the glasses is SiO2 36.11 wt%, Al2O312.19 wt%, CaO 24.44 wt%, FeO 10.06 wt%, MgO 9.19 wt%, Na2O 2.28 wt%, TiO2 2.02 wt%, K2O 1.12 wt%, P2O5 0.46 wt%. Glass transition temperature obtained by dilatometry varies from 640 oC (AG) to 700 oC (QG). The temperatures of nucleation and crystal growth of the glass have been determined by Differential Thermal Analysis (DTA). The phases formed after these treatments were identified by X-Ray Diffraction. The temperatures of exothermic and endothermic peaks measured in the quenched glass are, in average, 10 oC higher than those found for the annealed glass. The exothermic peaks provide crystallization temperatures for different phases: a first event at 857 oC corresponds to the growth of magnetite, pyroxene and nepheline, whereas a second event at 1030 oC is due to the crystallization of melilite from the reaction between previous minerals and a remaining amorphous phase. The complete melting of this system occurs at 1201 oC. This glass has been nucleated inside the DTA furnace (500-850° C/3 hours) and then heated up to 1300 oC using the fraction between 400-500μm. TN

  14. SC response characteristics of two kinds of coagulant

    Institute of Scientific and Technical Information of China (English)

    杨万东; 宋爽; 史惠祥

    2002-01-01

    Automatic coagulant dosage control with streaming current (SC) technique is introduced in this paper. Aluminum and ferric coagulants are widely used in surface water treatment. The SC response characteristics of P-AlCl3 aluminum coagulant and P-FeCl3 ferric coagulant were investigated in this work. Bench-scale water treatment results were obtained from jar tests including rapid mixing, flocculation and undisturbed sedimentation. Results showed that aluminum coagulant is more sensitive than ferric coagulant to SC response.

  15. SC response characteristics of two kinds of coagulant

    Institute of Scientific and Technical Information of China (English)

    杨万东; 宋爽; 史惠祥

    2002-01-01

    Automatic coagulant dosage control with streaming current (SC) technique is in troduced inthis paper. Aluminum and ferric coagulants are widely used in surface water treatment. The SC response characteristics of P-AiCI3 aluminum coagulant and P-FeCI3 ferric coagulant were investigated in this work. Bench-scale water treatment results were obtained from jar tests including rapid mixing,flocculation and undisturbed sedimentation. Results showed that aluminum coagulant is more sensitive than ferric coagulant to SC response.

  16. Final Scientific Report: DE-SC0002194

    Energy Technology Data Exchange (ETDEWEB)

    Seidler, Gerald [Univ. of Washington, Seattle, WA (United States)

    2017-04-07

    We provide the final scientific report for DE-SC0002194. During the term of this grant, 28 publications spanning a variety of topics were addressed under the rubric of advanced x-ray methods and their application to extreme conditions of time-resolution or x-ray intensities. Notable accomplishments include a new observation of XANES features associated with f-shell reconfiguration in lanthanides, size-dependent x-ray heating effects under XFEL illumination conditions, theoretical development of improved treatments of inelastic x-ray scattering for 'warm dense matter' conditions, and several new instrument develop efforts for atomic, molecular, and condensed phase studies in the lab and at major facility lightsources.

  17. Crystallization process

    Science.gov (United States)

    Adler, Robert J.; Brown, William R.; Auyang, Lun; Liu, Yin-Chang; Cook, W. Jeffrey

    1986-01-01

    An improved crystallization process is disclosed for separating a crystallizable material and an excluded material which is at least partially excluded from the solid phase of the crystallizable material obtained upon freezing a liquid phase of the materials. The solid phase is more dense than the liquid phase, and it is separated therefrom by relative movement with the formation of a packed bed of solid phase. The packed bed is continuously formed adjacent its lower end and passed from the liquid phase into a countercurrent flow of backwash liquid. The packed bed extends through the level of the backwash liquid to provide a drained bed of solid phase adjacent its upper end which is melted by a condensing vapor.

  18. Molecular Structure and Crystal Packing of n-Type Semiconducting Material 3′,3′-(1,4-Phenylene)bis{2′-(4′′-trifluoromethyl)phenyl}acrylonitrile

    OpenAIRE

    Tetsuji Moriguchi; Shuichi Nagamatsu; Tatsuo Okauchi; Akihiko Tsuge; Wataru Takashima; Shuji Hayase

    2014-01-01

    The exact molecular structure and the crystal packing of the n-type semiconducting material 3′,3′-(1,4-phenylene)bis{2′-(4′′-trifluoromethyl)phenyl}acrylonitrile was determined by a single crystal X-ray diffraction with twin treatment technique. The air-stable product was crystallized from dichloromethane-hexane mixed solution. The solid-state structure is the example of a typical π-π stacking with side intermolecular CN–H short contact networks.

  19. Diketonylpyridinium Cations as a Support of New Ionic Liquid Crystals and Ion-Conductive Materials: Analysis of Counter-Ion Effects

    Science.gov (United States)

    Pastor, María Jesús; Cuerva, Cristián; Campo, José A.; Schmidt, Rainer; Torres, María Rosario; Cano, Mercedes

    2016-01-01

    Ionic liquid crystals (ILCs) allow the combination of the high ionic conductivity of ionic liquids (ILs) with the supramolecular organization of liquid crystals (LCs). ILCs salts were obtained by the assembly of long-chained diketonylpyridinium cations of the type [HOOR(n)pyH]+ and BF4−, ReO4−, NO3−, CF3SO3−, CuCl42− counter-ions. We have studied the thermal behavior of five series of compounds by differential scanning calorimetry (DSC) and hot stage polarized light optical microscopy (POM). All materials show thermotropic mesomorphism as well as crystalline polymorphism. X-ray diffraction of the [HOOR(12)pyH][ReO4] crystal reveals a layered structure with alternating polar and apolar sublayers. The mesophases also exhibit a lamellar arrangement detected by variable temperature powder X-ray diffraction. The CuCl42− salts exhibit the best LC properties followed by the ReO4− ones due to low melting temperature and wide range of existence. The conductivity was probed for the mesophases in one species each from the ReO4−, and CuCl42− families, and for the solid phase in one of the non-mesomorphic Cl− salts. The highest ionic conductivity was found for the smectic mesophase of the ReO4− containing salt, whereas the solid phases of all salts were dominated by electronic contributions. The ionic conductivity may be favored by the mesophase lamellar structure. PMID:28773485

  20. Electrochemical synthesis of nanostructured porous materials using liquid crystal and colloidal templates and their magnetic and optical properties

    CERN Document Server

    Ghanem, M A M

    2002-01-01

    material, and that these magnetic properties vary systematically with the diameter of the spherical pores within the films. A new oscillation effect has been observed for the coercivity of macroporous Ni sub 8 sub 0 Fe sub 2 sub 0 film with different pore layer thickness. sphere templates, the resulting films show well-formed, regular, two- and three-dimensional macroporous networks consisting of spherical pores arranged in a highly ordered face centred cubic (fee) structure. The spherical voids are interconnected by a series of smaller windows that form an open porous structure embedded in the material framework. The diameter of the spherical pores can be precisely changed over the range from 200 to 1000 nm by changing the diameter of the latex spheres used to form the templates. The resulting macroporous material structures are robust, self-supported, dense, polycrystalline, uniform and free from filling defects and contamination or problems caused by shrinkage during processing. The nanostructured macropor...