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Sample records for crystal structures thermal

  1. Spectroscopic, thermal and structural studies on manganous malate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, J., E-mail: smartlabindia@gmail.com; Lincy, A., E-mail: lincymaria@gmail.com; Mahalakshmi, V.; Saban, K. V. [Smart Materials Analytic Research and Technology (SMART), Department of Physics, St. Berchmans College (India)

    2013-01-15

    Prismatic crystals of manganous malate have been prepared by controlled ionic diffusion in hydrosilica gel. The structure was elucidated using single crystal X-ray diffraction. The crystals are orthorhombic with space group Pbca. Vibrations of the functional groups were identified by the FTIR spectrum. Thermogravimetric and differential thermal analyses (TG-DTA) were carried out to explore the thermal decomposition pattern of the material. Structural information derived from FTIR and TG-DTA studies is in conformity with the single crystal XRD data.

  2. Preparation, Crystal Structure, and Thermal Analysis of Carbohydrazide Trinitrophloroglucinolate

    Institute of Scientific and Technical Information of China (English)

    LIU Zhen-hua; ZHANG Tong-lai; HU Xiao-chun; ZHANG Jian-guo; YANG Li; QIAO Xiao-jing

    2008-01-01

    A new compound (CHZ)(HTNPG).0.5H2O was synthesized by mixing carbohydrazide(CHZ) and trinitrophloroglucinol(TNPG) and characterized by elemental analysis and Fourier transform infrared (FTIR) spectrum.Its crystal structure was determined by single crystal X-ray diffraction analysis.The crystal belongs to triclinic system,P1 space group,with a=0.45578(9) nm,b=1.0142(2) nm,c=1.3041(3) nm,a=86.53(3)°,β=99.56(3)°,γ=81.94(3)°,V=0.5958(2) nm3,Z=2,Dc=2.008 g/cm3,R1=0.0476,and wR2=O.1139.The compound is a di-substituted salt of TNPG,which consists of a cation (CHZ)2+ and an anion (HTNPG)2-.The thermal analysis of the compound was studied by means of differential scanning calorimetry(DSC) and thermogravimetry-derivative thermogravimetry(TG-DTG).Under nitrogen atmosphere at a heating rate of 10 ℃/min,the thermal decomposition of the compound contained one endothermic process of dehydrating stage and two intense exothermic decomposition processes in a temperature range of 140--232℃ on the DSC trace.The decomposition products of the title compound are nearly gaseous products.The existing complicated hydrogen bond networks and electrostatic attraction between (CHZ)2+ and (HTNPG)2-enhance the thermal stability of the title compound.

  3. Novel Magnesium Salt Based on BTATz: Crystal Structure,Thermal Behavior and Thermal Safety

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-bo; REN Ying-hui; LI Wen; ZHAO Feng-qi; WANG Bo-zhou; SONG Ji-rong

    2013-01-01

    A new high-energy organic magnesium salt [Mg(H2O)6](BTATz)·2H2O[BTATz=3,6-bis(1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine] was synthesized and characterized by elemental analysis and Fourier transform infrared(FTIR) spectrometry.Its crystal structure was determined by X-ray single crystal diffraction.The crystal belongs to monoclinic system with space group C2/c and a=2.1329(7) nm,b=0.52275(16) nm,c=1.5909(5) nm,β=100.471(6)°,V=1.7443(9) nm3,Z=4,μ=0.361 mm-1,F(000)=900 and Dc=1.644 g/cm3.Meanwhile,the thermal behavior of [Mg(H2O)6](BTATz)·2H2O was studied under the non-isothermal conditions by differential scanning calorimetry(DSC) and thermalgravity-differential thermalgravity(TG-DTG) methods.The enthalpy,apparent activation energy and per-exponential factor of the main exothermic decomposition reaction are 898.88 J/g,139.2 kJ/mol and 1010.48 S-1,respectively.The values of the self-accelerating decomposition temperature(TsADT),the thermal ignition temperature(TTIT) and the critical temperature of thermal explosion(Tb) for [Mg(H2O)6](BTATz).2H2O are 515.13,532.08 and 565.99 K,respectively.

  4. ORTEP-III: Oak Ridge Thermal Ellipsoid Plot Program for crystal structure illustrations

    Energy Technology Data Exchange (ETDEWEB)

    Burnett, M.N.; Johnson, C.K.

    1996-07-01

    This report describes a computer program for drawing crystal structure illustrations. Ball-and-stick type illustrations of a quality suitable for publication are produced with either spheres or thermal-motion probability ellipsoids on the atomic sites. The program can also produce stereoscopic pairs of illustrations which aid in the visualization of complex packing arrangements of atoms and thermal motion patterns. Interatomic distances, bond angles, and principal axes of thermal motion are also calculated to aid the structural study.

  5. Synthesis, growth, structural, thermal and optical studies of pyrrolidinium-2-carboxylate-4-nitrophenol single crystals

    Science.gov (United States)

    Swarna Sowmya, N.; Sampathkrishnan, S.; Vidyalakshmi, Y.; Sudhahar, S.; Mohan Kumar, R.

    2015-06-01

    Organic nonlinear optical material, pyrrolidinium-2-carboxylate-4-nitrophenol (PCN) was synthesized and single crystals were grown by slow evaporation solution growth method. Single crystal X-ray diffraction analysis confirmed the structure and lattice parameters of PCN crystals. Infrared, Raman and NMR spectral analyses were used to elucidate the functional groups present in the compound. The thermal behavior of synthesized compound was studied by thermogravimetric and differential scanning calorimetry (TG-DSC) analyses. The photoluminescence property was studied by exciting the crystal at 360 nm. The relative second harmonic generation (SHG) efficiency of grown crystal was estimated by using Nd:YAG laser with fundamental wavelength of 1064 nm.

  6. OR TEP-II: a FORTRAN Thermal-Ellipsoid Plot Program for crystal structure illustrations

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, C.K.

    1976-03-01

    A computer program is described for drawing crystal structure illustrations using a mechanical plotter. Ball-and-stick type illustrations of a quality suitable for publication are produced with either spheres or thermal-motion probability ellipsoids on the atomic sites. The program can produce stereoscopic pairs of illustrations which aid in the visualization of complex packing arrangements of atoms and thermal motion patterns. Interatomic distances, bond angles, and principal axes of thermal motion are also calculated to aid the structural study. The most recent version of the program, OR TEP-II, has a hidden-line-elimination feature to omit those portions of atoms or bonds behind other atoms or bonds.

  7. Bis-methyl imidazolium methylidene bis(trifluoromethanesulfonyl)imide, crystal structure, thermal and dielectric studies

    Indian Academy of Sciences (India)

    BOUMEDIENE HADDAD; TAQIYEDDINE MOUMENE; DIDIER VILLEMIN; JEAN-FRANÇOIS LOHIER; EL-HABIB BELARBI

    2016-06-01

    A new geminal di-cationic ionic liquid (IL) containing a central cationic unit methylidene capped by a basic functionality (imidazole) is synthesized. The compound was characterized by means of ${}^1$H, ${}^13$C, ${}^19$F NMR, IR and Raman spectroscopies and its crystal structure is confirmed by single crystal X-ray diffraction method. The X-ray studies on ([M(CH$_2$)IM$^{2+}$][2NTf$^−_2$ ]) show that it crystallizes in monoclinic system with space group:P 21/c. Thermal properties were investigated in the temperature range from 0 to 400$^{\\circ}$C by using differential thermal (DTA) and thermogravimetric (TGA) analyses. The frequency-dependent electrical data are discussed using complexdielectric permittivity in the frequency range of ($10^{−2}–10^6$ Hz) and in the temperature range of $−50–20^{\\circ}$C. The outstanding dielectric and thermal properties make this IL as promising candidate for electrochemical devices.

  8. Effects of Thermal Exposure on Structures of DD6 Single Crystal Superalloy with Thermal Barrier Coatings

    Directory of Open Access Journals (Sweden)

    DONG Jianmin

    2016-10-01

    Full Text Available In order to investigate the effect of water grit-blasting and high temperature thermal exposure on the microstructures of DD6 alloy with TBCs, DD6 single crystal superalloy specimens were water grit-blasted with 0.3 MPa pressure, then the specimens were coated with thermal barrier coatings by electron beam physical vapor deposition (EB-PVD. Specimens with TBCs were exposed at 1100℃ for 50 and 100 hours in the air respectively, and then these specimens were subjected to stress-rupture tests under the condition of 1100℃/130 MPa. The results show that grit-blasting doesn't lead into the recrystallization, thermal exposure can induce element interdiffusion between the bond coat and alloy substrate, the residual stress and element diffusion lead into the changes of γ' phase coarsing direction. After stress rupture tests, the secondary reaction zone emerges into a local area.

  9. Structural, spectral, thermal, dielectric, mechanical and optical properties of urea L-alanine acetate single crystals

    Science.gov (United States)

    Jaikumar, D.; Kalainathan, S.; Bhagavannarayana, G.

    2010-05-01

    A new organic nonlinear optical crystal, urea L-alanine acetate (ULAA) has been grown by solution growth using slow cooling technique with the vision to improve the properties of the L-alanine crystals. Urea and L-alanine material were mixed in the molar ratio 1:4. Solubility and metastable zone width were determined. Single crystal XRD analyses revealed that the crystal lattice of ULAA is orthorhombic system, primitive lattice with cell parameters a=5.7971 Å, b=6.0391 Å, c=12.3276 Å with space group P2 12 12 1 (D 24). High-resolution X-ray diffraction (HR-XRD) analysis was carried out to study their crystalline perfection. FTIR spectrum was recorded to identify the presence of functional groups and molecular structure was confirmed by 1H NMR spectrum. From the mass spectrum, the ratio of compound formation of ULAA was analyzed. Thermal strength of the grown crystal has been studied using thermo-gravimetric (TG) and differential thermal analysis (DTA). Dielectric measurements reveal that the grown crystals have very low dielectric loss. The mechanical behavior was studied by Vickers microhardness test. The grown crystals were found to be transparent in the entire visible region. Preliminary measurement using Kurtz powder technique with Nd-YAG laser light of wavelength 1064 nm indicates that their second harmonic generation (SHG) efficiency is roughly equal to that of pure KDP.

  10. Temperature Distribution and Thermal Deformation of the Crystallization Roller Based on the Direct Thermal-Structural Coupling Method

    Science.gov (United States)

    Pan, Liping; He, Zhu; Li, Baokuan; Zhou, Kun; Sun, Ke

    2017-03-01

    The temperature distribution and the thermal deformation of the crystallization roller have a significant effect on the forming process of the thin steel strip. Finite element analysis has been used to simulate the temperature distribution and the thermal deformation in a crystallization roller through the direct thermal-structural coupling analysis method. Various parameters, such as different rotational velocities, diverse locations of cooling water pipes, and typical velocities of cooling water have been systematically investigated. It is found that the temperature and the equivalent stress of the outer surface reach the steady state after 30 s of rotations, and they are influenced remarkably by the factors of rotational velocity and cooling water pipe depth. Meanwhile, the radial displacement approaches the steady state after 300 s of revolutions and is significantly affected by the cooling water velocity.

  11. Temperature Distribution and Thermal Deformation of the Crystallization Roller Based on the Direct Thermal-Structural Coupling Method

    Science.gov (United States)

    Pan, Liping; He, Zhu; Li, Baokuan; Zhou, Kun; Sun, Ke

    2016-12-01

    The temperature distribution and the thermal deformation of the crystallization roller have a significant effect on the forming process of the thin steel strip. Finite element analysis has been used to simulate the temperature distribution and the thermal deformation in a crystallization roller through the direct thermal-structural coupling analysis method. Various parameters, such as different rotational velocities, diverse locations of cooling water pipes, and typical velocities of cooling water have been systematically investigated. It is found that the temperature and the equivalent stress of the outer surface reach the steady state after 30 s of rotations, and they are influenced remarkably by the factors of rotational velocity and cooling water pipe depth. Meanwhile, the radial displacement approaches the steady state after 300 s of revolutions and is significantly affected by the cooling water velocity.

  12. ReSe2: a reassessment of crystal structure and thermal analysis

    Science.gov (United States)

    Jariwala, Bhakti; Thamizhavel, Arumugum; Bhattacharya, Arnab

    2017-02-01

    The rhenium-based layered dichalcogenide ReSe2 crystallizes in a distorted triclinic structure which results in unique, anisotropic electronic and optical properties. This, along with a weak layer-dependence of band gap has made ReSe2 a subject of intense contemporary research interest. However, there has been no agreement on the exact crystal structure of this material, or knowledge of its thermal properties like the melting point. In this work, we perform single crystal, Laue, and powder diffraction measurements on high-quality ReSe2 crystals synthesized using a modified Bridgman technique. We confirm the presence of triclinic symmetry (P\\bar{1} -space group) and support the view that that ReSe2 has a distorted CdCl2-type structure (rather than Cd(OH)2 as initially proposed) and obtain lattice parameter values of a  =  6.5791(8) Å, b  =  6.6897(10) Å, and c  =  6.7013(11) Å. Further, thermal measurements on these crystals show a clear endothermic peak at around 1115 °C pointing to a melting transition, and show no other phase transitions up to 1300 °C.

  13. Synthesis, structure, thermal and NLO characterization of 4-hydroxy tetramethylpiperazinium picrate crystals

    Indian Academy of Sciences (India)

    T Dhanabal; G Amirthaganesan; M Dhandapani; Samar K Das

    2012-07-01

    Good quality single crystals of 4-hydroxy tetramethylpiperazinium picrate (TMPP) were grown by slow evaporation solution growth method at room temperature. The average dimensions of the grown crystals were 0.6 × 0.2 × 0.2 cm3. The solubility of the compound was estimated using methanol and acetone. The elemental analysis confirms the formation of the compound in the stoichiometric proportion. The UV-visible transmittance study indicates that the crystal possesses minimum transmittance at 370 nm and no absorption at 470-900 nm. The Bragg peaks obtained in the powder X-ray diffraction pattern confirm its crystallinity. The thermal behaviour of the crystal was investigated using thermogravimetric (TG) and differential thermal analysis (DTA) techniques. The structure of the compound was determined by using single crystal X-ray diffraction method. The compound was found to be crystallize in the monoclinic space group P2(1)/c (a = 6.9513(8)Å, b = 11.8016(14)Å, c = 22.018(2)Å, = 90.00°, = 92.575(2)°, = 90.00°). The thermal anomalies observed in the differential scanning calorimetry (DSC) heating and cooling cycles indicate the occurrence of first order phase transition. Fourier transform infrared (FTIR) and polarized Raman spectral analyses were used to confirm the presence of various functional groups in the compound. The nonlinear optical property (NLO) of the crystal was analysed by Kurtz-Perry powder technique and found that the compound has SHG efficiency 1.5 times greater that of potassium dihydrogen phosphate (KDP).

  14. Effect of dopants on crystal structure and thermal properties of pentaglycerine

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, D.; Ding, W. [Univ. of Nevada, Reno, NV (United States)

    1989-03-01

    The overall objective of this research program is to develop practical solid-state thermal energy storage materials. Research is focused on polyalcohol {open_quotes}Plastic Crystals{close_quotes} which undergo crystallographic changes at constant transition temperature absorbing or releasing amounts of latent heat. The known pure polyalcohols have high transition temperatures; therefore, adjustment of transformation temperature is important to develop practical materials. The approach taken is to introduce substitutional and interstitial dopants so as to strain the lattice of the host crystal which results in lowering the transition temperature. Current research is on temperature adjustment of pentaglycerine [PG] (C{sub 5}H{sub 12}O{sub 3}) initiated approximately four months ago. Results, so far, show that the substitutional dopants are more effective in reducing the transition temperature than interstitial dopants. The results in the first phase of this program show that the transition temperature of PG reduced significantly by using trimethylol propane [TMP] (C{sub 6}H{sub 14}O{sub 3}), 2-amino 2-methyl 1,3 propanediol [AMPL] (C{sub 4}H{sub 11}NO{sub 2}) as dopants. It appears that some of these doped samples have near room temperature transitions; however, these results are not conclusive at this time. Recently, it was discovered that TMP has an additional solid-solid phase transformation, slightly below room temperature. Crystal structure analyses showed some surprising results with regards to thermal expansion behavior of PG. Several sets of low as well as high temperature data were obtained from the pure and doped PG to characterize the structural changes, if any, and the thermal expansions. Research is in progress on crystal structure and thermal analyses.

  15. Dislocation structure of Ge crystals grown by low thermal gradient Czochralski technique

    Science.gov (United States)

    Trukhanov, E. M.; Fritzler, K. B.; Vasilenko, A. P.; Kolesnikov, A. V.; Kasimkin, P. V.; Moskovskih, V. A.

    2017-06-01

    Dislocation structure of the Ge single crystals grown by Czochralski method with low thermal gradient has been studied. The selective etching technique and the X-Ray transmission and reflection topography were used. Clearly defined non-uniform dislocation distribution over the crystal cross - section is revealed. Helical dislocations and sets of prismatic dislocation loops are registered. Helical dislocations perpendicular to the ingot axis are situated near the boundary between the regions with low and high dislocation densities (102 and 103 cm-2, respectively). Their length can be as much as several millimeters. Dislocation formations lying at a 35.3° to the crystal axis along directions are also observed. These formations have the shape of prism confined by {111} planes.

  16. Thermal evolution of the crystal structure of the orthorhombic perovskite LaFeO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Charlotte A.L.; Kavanagh, Christopher M. [School of Chemistry and EaStCHEM, University of St Andrews, St Andrews KY16 9ST (United Kingdom); Knight, Kevin S.; Kockelmann, Winfried [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); Morrison, Finlay D. [School of Chemistry and EaStCHEM, University of St Andrews, St Andrews KY16 9ST (United Kingdom); Lightfoot, Philip, E-mail: pl@st-and.ac.uk [School of Chemistry and EaStCHEM, University of St Andrews, St Andrews KY16 9ST (United Kingdom)

    2015-10-15

    The thermal evolution of the crystal structure of the prototypical orthorhombic perovskite LaFeO{sub 3} has been studied in detail by powder neutron diffraction in the temperature range 25thermal behavior to be understood. In particular, the largest-amplitude symmetry modes (viz. in-phase and out-of-phase octahedral tilts, and A-site cation displacements) are shown to display relatively ‘normal’ behavior, increasing with decreasing temperature, which contrasts with the anomalous behavior previously shown by the derivative Bi{sub 0.5}La{sub 0.5}FeO{sub 3}. However, an unexpected behavior is seen in the nature of the intra-octahedral distortion, which is used to rationalize the unique occurrence of a temperature dependent crossover of the a and c unit cell metrics in this compound. - Graphical abstract: The unusual thermal evolution of lattice metrics in the perovskite LaFeO{sub 3} is rationalized from a detailed powder neutron diffraction study. - Highlights: • Crystal structure of the perovskite LaFeO{sub 3} studied in detail by powder neutron diffraction. • Unusual thermal evolution of lattice metrics rationalized. • Contrasting behavior to Bi-doped LaFeO{sub 3}. • Octahedral distortion/tilt parameters explain unusual a and c lattice parameter behavior.

  17. Synthesis,Crystal Structure and Thermal Stability of(Diacetylacetone)(diimidazole)Nickel(Ⅱ)Complex

    Institute of Scientific and Technical Information of China (English)

    建方方; 庞蕾; 肖海连; 孙萍萍

    2004-01-01

    The title compound, [Ni(acac)2(Im)2] (acac = acetylacetone), has been obtained by the reaction of Ni(acac)2 with imidazole ligand in the ethanol solvent. The blue crystal is of triclinic, space group Pī with a = 7.472(2), b = 9.456(2), c = 13.823(3)A, α = 85.55(3), β = 89.03(3), γ = 80.63(3)o, C16H22N4NiO4, Mr = 393.09, V = 960.7(3)A3, Z = 2, Dc = 1.359 g/cm3, F(000) = 412, μ = 1.036 mm-1, R = 0.0549 and wR = 0.1615. The crystal structure consists of two disconnected structural units. Each Ni atom coordinated by two N atoms from two imidazole ligands and four O atoms from two acetylactone ligands adopts a slightly distorted octahedron. The structure characterization was performed by means of IR, UV, TG, elemental analysis and single-crystal X-ray analysis. The thermal gravity (TG) data indicate that thermal decomposition of the title compound takes place in two steps, and the residue is NiO.

  18. Tungsten Incorporation into Gallium Oxide: Crystal Structure, Surface and Interface Chemistry, Thermal Stability and Interdiffusion

    Energy Technology Data Exchange (ETDEWEB)

    Rubio, E. J.; Mates, T. E.; Manandhar, S.; Nandasiri, M.; Shutthanandan, V.; Ramana, C. V.

    2016-12-01

    Tungsten (W) incorporated gallium oxide (Ga2O3) (GWO) thin films were deposited by radio-frequency magnetron co-sputtering of W-metal and Ga2O3-ceramic targets. Films were produced by varying sputtering power applied to the W-target in order to achieve variable W-content (0-12 at%) into Ga2O3 while substrate temperature was kept constant at 500 °C. Chemical composition, chemical valence states, microstructure and crystal structure of as-deposited and annealed GWO films were evaluated as a function of W-content. The structural and chemical analyses indicate that the samples deposited without any W-incorporation are stoichiometric, nanocrystalline Ga2O3 films, which crystallize in β-phase monoclinic structure. While GWO films also crystallize in monoclinic β-Ga2O3 phase, W-incorporation induces surface amorphization as revealed by structural studies. The chemical valence state of Ga ions probed by X-ray photoelectron spectroscopic (XPS) analyses is characterized by the highest oxidation state i.e., Ga3+. No changes in Ga chemical state are noted for variable W-incorporation in the range of 0-12 at%. Rutherford backscattering spectrometry (RBS) analyses indicate the uniform distribution of W-content in the GWO films. However, XPS analyses indicate the formation of mixed valence states for W ions, which may be responsible for surface amorphization in GWO films. GWO films were stable up to 900 oC, at which point thermally induced secondary phase (W-oxide) formation was observed. A transition to mesoporous structure coupled with W interdiffusion occurs due to thermal annealing as derived from the chemical analyses at the GWO films’ surface as well as depth-profiling towards the GWO-Si interface. A model has been formulated to account for the mechanism of W-incorporation, thermal stability and interdiffusion via pore formation in GWO films.

  19. Synthesis, growth, structural, optical, thermal, electrical and mechanical properties of hydrogen bonded organic salt crystal: Triethylammonium-3, 5-dinitrosalicylate

    Science.gov (United States)

    Rajkumar, Madhu; Chandramohan, Angannan

    2017-04-01

    Triethylammonium-3, 5-dinitrosalicylate, an organic salt was synthesized and single crystals grown by slow solvent evaporation solution growth technique using methanol as a solvent. The presence of various functional groups and mode of vibrations has been confirmed by FT-IR spectroscopic technique. The UV-vis-NIR Spectrum was recorded in the range 200-1200 nm to find optical transmittance window and lower cut off wavelength of the title crystal. The formation of the salt and the molecular structure was confirmed by NMR spectroscopic technique. Crystal system, crystalline nature, cell parameters and hydrogen bonding interactions of the grown crystal were determined by single crystal x-ray diffraction analysis. The thermal characteristics of grown crystal were analyzed by thermo gravimetric and differential thermal analyses. Dielectric studies were carried out to study the distribution of charges within the crystal. The mechanical properties of the title crystal were studied by Vicker's microhardness technique.

  20. How important is thermal expansion for predicting molecular crystal structures and thermochemistry at finite temperatures?

    Science.gov (United States)

    Heit, Yonaton N; Beran, Gregory J O

    2016-08-01

    Molecular crystals expand appreciably upon heating due to both zero-point and thermal vibrational motion, yet this expansion is often neglected in molecular crystal modeling studies. Here, a quasi-harmonic approximation is coupled with fragment-based hybrid many-body interaction calculations to predict thermal expansion and finite-temperature thermochemical properties in crystalline carbon dioxide, ice Ih, acetic acid and imidazole. Fragment-based second-order Möller-Plesset perturbation theory (MP2) and coupled cluster theory with singles, doubles and perturbative triples [CCSD(T)] predict the thermal expansion and the temperature dependence of the enthalpies, entropies and Gibbs free energies of sublimation in good agreement with experiment. The errors introduced by neglecting thermal expansion in the enthalpy and entropy cancel somewhat in the Gibbs free energy. The resulting ∼ 1-2 kJ mol(-1) errors in the free energy near room temperature are comparable to or smaller than the errors expected from the electronic structure treatment, but they may be sufficiently large to affect free-energy rankings among energetically close polymorphs.

  1. Crystal structure and thermal expansion of Mn(1-x)Fe(x)Ge.

    Science.gov (United States)

    Dyadkin, Vadim; Grigoriev, Sergey; Ovsyannikov, Sergey V; Bykova, Elena; Dubrovinsky, Leonid; Tsvyashchenko, Anatoly; Fomicheva, L N; Chernyshov, Dmitry

    2014-08-01

    A series of temperature-dependent single-crystal and powder diffraction experiments has been carried out using synchrotron radiation in order to characterize the monogermanides of Mn, Fe and their solid solutions. The MnGe single crystal is found to be enantiopure and we report the absolute structure determination. The thermal expansion, parametrized with the Debye model, is discussed from the temperature-dependent powder diffraction measurements for Mn(1-x)Fe(x)Ge (x = 0, 0.1, 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.7, 0.75, 0.8, 0.9). Whereas the unit-cell dimension and the Debye temperature follow a linear trend as a function of composition, the thermal expansion coefficient deviates from linear dependence with increasing Mn content. No structural phase transformations have been observed for any composition in the temperature range 80-500 K for both single-crystal and powder diffraction, indicating that the phase transition previously observed with neutron powder diffraction most probably has a magnetic origin.

  2. Crystal Structure Effects on the Thermal Conductivity of Cu-Ge-Se Compounds

    Science.gov (United States)

    Skoug, Eric; Cain, Jeffrey; Morelli, Donald

    2010-03-01

    One approach to increasing the efficiency of a thermoelectric material is to decrease its thermal conductivity without degrading its electronic properties. Traditionally this has been accomplished, for instance, by forming solid solutions between compounds with similar crystal structures, or, more recently, by inducing nanostructure in the crystal lattice. These methods have proven effective in many cases; however discovering compounds with intrinsically low thermal conductivity provides a fundamental solution to the same problem. Here we describe our initial efforts in synthesis and characterization of compounds of the series Cu2Ge1+xSe3, in which we observe a transition from orthorhombic to cubic symmetry at x = 0.55. The lattice thermal conductivity of the cubic phase is significantly lower than that of the orthorhombic phase, which we discuss here in relation to vacancies and anti-site defects. A simple valence argument is presented suggesting a change in the nominal valence of Ge as x approaches 1.0, which we speculate contributes to increased bond anharmonicity in the cubic-structure compounds.

  3. Co-crystals of the antiretroviral nevirapine: crystal structures, thermal analysis and dissolution behaviour

    OpenAIRE

    Aucamp, Marique Elizabeth; Engel, Emile; Liebenberg, Wilna; Stieger, Nicole; Caira, Mino R.; Susan A. Bourne

    2012-01-01

    Synthesis and physicochemical characterization of co-crystals of the antiretroviral drug nevirapine (NV) with the pharmaceutically acceptable co-formers saccharin, rac-tartaric acid, maleic acid, glutaric acid and salicylic acid are reported for the first time. The respective stoichiometric NV : co-former ratios are 2 : 1, 1 : 1, 1 : 1, 1 : 1 and 2 : 1. In the 1 : 1 co-crystals, the predicted R22(8) NV(amide)–carboxylic acid supramolecular synthon occurs, whereas in the 2 : 1 species, the co-...

  4. Growth, crystal structure and thermal properties of calcium bis(malate) dihydrate

    Energy Technology Data Exchange (ETDEWEB)

    Jini, T. [Department of Physics, St. Berchmans College, Changanassery 686 101, Kerala (India); Saban, K.V. [Department of Physics, St. Berchmans College, Changanassery 686 101, Kerala (India); Varghese, G. [Department of Physics, St. Berchmans College, Changanassery 686 101, Kerala (India); Naveen, S. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India); Sridhar, M.A. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India)]. E-mail: mas@physics.uni-mysore.ac.in; Prasad, J.S. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India)

    2007-05-16

    A new coordination compound crystal of calcium with malic acid is prepared by gel aided solution growth. Single crystal X-ray diffraction studies revealed that the structural formula of the compound is Ca(C{sub 4}H{sub 4}O{sub 5}){sub 2}.2H{sub 2}O. It crystallizes in the monoclinic system with space group C2/c, Z = 4, with unit cell parameters a = 15.916(9) A, b = 5.886(3) A, c = 13.046(6) A and {beta} = 90.678(4){sup o}. Data were collected by oscillation method and full-matrix least squares refinement was applied to the model converging to final R indices R {sub 1} = 0.0416 and {omega}R {sub 2} = 0.1255. Compound forms a layer-type polymeric structure, stabilized by intermolecular hydrogen bonding. Ca{sup 2+} is eight-fold coordinated. Malate is coordinated to Ca{sup 2+} tridendate-bidendate through two carboxylates and monodendate through oxygen atom of the hydroxyl group. Thermal behavior investigated using TG and DTA studies is in conformity with the proposed structure.

  5. Crystal growth, structural and thermal studies of amino acids admixtured L-arginine phosphate monohydrate single crystals

    Science.gov (United States)

    Anandan, P.; Saravanan, T.; Parthipan, G.; Kumar, R. Mohan; Bhagavannarayana, G.; Ravi, G.; Jayavel, R.

    2011-05-01

    To study the improved characteristics of L-arginine phosphate monohydrate (LAP) crystals, amino acids mixed LAP crystals have been grown by slow cooling method. Amino acids like glycine, L-alanine, and L-valine have been selected for doping. Optical quality bulk crystals have been harvested after a typical growth period of about twenty days. The effect of amino acids in the crystal lattice and molecular vibrational frequencies of various functional groups in the crystals have been studied using X-ray powder diffraction and Fourier Transform infrared (FTIR) analyses respectively. Thermal behavior of the amino acids mixed LAP crystals have been studied from the TG and DTG analyses. High-resolution X-ray diffraction studies have been carried out to find the crystalline nature. Optical transmission studies have been carried out by UV-vis spectrophotometer. The cut off wavelength is below 240 nm for the grown crystals.

  6. Growth aspects, structural, optical, thermal and mechanical properties of benzotriazole pyridine-2-carboxylic acid single crystal

    Science.gov (United States)

    Thirunavukkarsu, A.; Sujatha, T.; Umarani, P. R.; Nizam Mohideen, M.; Silambarasan, A.; Kumar, R. Mohan

    2017-02-01

    Benzotriazole pyridine-2-carboxylic acid single crystal (BTPCA) was grown by slow evaporation solution growth technique. The cell parameters and crystallinity of BTPCA crystal were found by single crystal and powder X-ray diffraction studies. The presence of functional groups was studied by FT-IR analysis. UV-vis-NIR transmission studies reveal that the BTPCA crystal is transparent in the entire visible region with lower optical cut-off wavelength of 306 nm. The thermal stability, melting point and decomposition stages of BTPCA were analysed from the thermogravimetric and differential thermal analyses. The second harmonic output power of BTPCA was measured to be 2.5 times that of KDP reference crystal. Hardness studies reveal that grown crystal shows the reverse indentation size effect and breakeven point due to release of internal fatigue generated during indentation.

  7. Growth, structural, spectral, optical, and thermal studies on amino acid based new NLO single crystal: L-phenylalanine-4-nitrophenol

    Science.gov (United States)

    Prakash, M.; Lydia Caroline, M.; Geetha, D.

    2013-05-01

    A new organic nonlinear optical single crystal, L-phenylalanine-4-nitrophenol (LPAPN) belonging to the amino acid group has been successfully grown by slow evaporation technique. The lattice parameters of the grown crystal have been determined by X-ray diffraction studies. FT-IR spectrum was recorded to identify the presence of functional group and molecular structure was confirmed by NMR spectrum. Thermal strength of the grown crystal has been studied using TG-DTA analyses. The grown crystals were found to be transparent in the entire visible region. The existence of second harmonic generation signals was observed using Nd:YAG laser with fundamental wavelength of 1064 nm.

  8. Crystal growth, structural, thermal and mechanical behavior of L-arginine 4-nitrophenolate 4-nitrophenol dihydrate (LAPP) single crystals

    Science.gov (United States)

    Mahadevan, M.; Ramachandran, K.; Anandan, P.; Arivanandhan, M.; Bhagavannarayana, G.; Hayakawa, Y.

    2014-12-01

    Single crystals of L-arginine 4-nitrophenolate 4-nitrophenol dihydrate (LAPP) have been grown successfully from the solution of L-arginine and 4-nitrophenol. Slow evaporation of solvent technique was adopted to grow the bulk single crystals. Single crystal X-ray diffraction analysis confirms the grown crystal has monoclinic crystal system with space group of P21. Powder X-ray diffraction analysis shows the good crystalline nature. The crystalline perfection of the grown single crystals was analyzed by HRXRD by employing a multicrystal X-ray diffractometer. The functional groups were identified from proton NMR spectroscopic analysis. Linear and nonlinear optical properties were determined by UV-Vis spectrophotometer and Kurtz powder technique respectively. It is found that the grown crystal has no absorption in the green wavelength region and the SHG efficiency was found to be 2.66 times that of the standard KDP. The Thermal stability of the crystal was found by obtaining TG/DTA curve. The mechanical behavior of the grown crystal has been studied by Vicker's microhardness method.

  9. Synthesis, Crystal Structure, and Thermal Decomposition of the Cobalt(II Complex with 2-Picolinic Acid

    Directory of Open Access Journals (Sweden)

    Di Li

    2014-01-01

    Full Text Available The cobalt(II complex of 2-picolinic acid (Hpic, namely, [Co(pic2(H2O2]·2H2O, was synthesized with the reaction of cobalt acetate and 2-picolinic acid as the reactants by solid-solid reaction at room temperature. The composition and structure of the complex were characterized by elemental analysis, infrared spectroscopy, single crystal X-ray diffraction, and thermogravimetry-differential scanning calorimetry (TG-DSC. The crystal structure of the complex belongs to monoclinic system and space group P2(1/n, with cell parameters of a=9.8468(7 Å, b=5.2013(4 Å, c=14.6041(15 Å, β=111.745(6°, V=747.96(11 Å3, Z=2, Dc=1.666 g cm−3, R1=0.0297, and wR2=0.0831. In the title complex, the Co(II ion is six-coordinated by two pyridine N atoms and two carboxyl O atoms from two 2-picolinic acid anions, and two O atoms from two H2O molecules, and forming a slightly distorted octahedral geometry. The thermal decomposition processes of the complex under nitrogen include dehydration and pyrolysis of the ligand, and the final residue is cobalt oxalate at about 450°C.

  10. Crystal Structures of Furazanes

    OpenAIRE

    Klapötke, Thomas; Schmid, Philipp; Stierstorfer, Jörg

    2015-01-01

    Several nitrogen-rich salts of 3-nitramino-4-nitrofurazane and dinitraminoazoxyfurazane were synthesized and characterized by various spectroscopic methods. The crystal structures were determined by low temperature single crystal X-ray diffraction. Moreover the sensitivities toward thermal and mechanical stimuli were determined by differential thermal analysis (DTA) and BAM (Bundesanstalt für Materialforschung und -prüfung) methods. The standard enthalpies of formation were calculated for all...

  11. Synthesis, X-ray crystal structures, thermal and electrochemical properties of thiosemicarbazidatodioxouranium(VI) complexes.

    Science.gov (United States)

    Sahin, Musa; Koca, Atıf; Ozdemir, Namık; Dinçer, Muharrem; Büyükgüngör, Orhan; Bal-Demirci, Tülay; Ulküseven, Bahri

    2010-11-14

    The stable uranyl complexes, [UO(2)(L)C(9)H(19)OH], were obtained from 3,5-dichlorosalicyl-(L(I)) and salicyl-aldehyde-S-propyl-thiosemicarbazones (L(II)) with substituted-salicylaldehyde in nonyl alcohol. The structures of the complexes have been characterized by elemental analysis, IR, (1)H NMR, conductivity, magnetic moment measurements, cyclic voltammetry, thermal gravimetric analysis and single crystal X-ray diffraction technique. The U(VI) centre is seven-coordinated in a distorted pentagonal bipyramidal geometry. The relative orientations of the nonyl alcohol and S-propyl group in the title complexes are completely different due to different crystal packing. Electrochemical behaviors of the thiosemicarbazone ligands and the uranyl complexes were studied using cyclic voltammetry and square wave voltammetry. Redox processes of the compounds are significantly influenced by the central metal ions and the nature of substituents on the thiosemicarbazones, which are important factors in controlling the redox properties. In situ spectroelectrochemical studies were employed to determine the colors and spectra of electro-generated species of the complexes.

  12. Structural, quantum chemical, vibrational and thermal studies of a hydrogen bonded zwitterionic co-crystal (nicotinic acid: pyrogallol)

    Science.gov (United States)

    Prabha, E. Arockia Jeya Yasmi; Kumar, S. Suresh; Athimoolam, S.; Sridhar, B.

    2017-02-01

    In the present work, a new co-crystal of nicotinic acid with pyrogallol (NICPY) has been grown in the zwitterionic form and the corresponding structural, vibrational, thermal, solubility and anti-cancer characteristics have been reported. The single crystal X-ray diffraction analysis confirms that the structural molecular packing of the crystal stabilized through N-H⋯O and O-H⋯O hydrogen bond. The stabilization energy of the hydrogen bond motifs were calculated in the solid state. Vibrational spectral studies such as Fourier transform-infrared (FT-IR) and FT-Raman were adopted to understand the zwitterionic co-crystalline nature of the compound, which has been compared with theoretically calculated vibrational frequencies. The thermal stability of the grown co-crystal was analyzed by TG/DTA study. The solubility of the NICPY co-crystal was investigated in water at different temperature and compared with that of the nicotinic acid, which is the parent compound of NICPY co-crystal. The grown crystals were treated with human cervical cancer cell line (HeLa) to analyze the cytotoxicity of NICPY crystals and compared with the parent compound, which shows that NICPY has moderate activity against human cervical cancer cell line.

  13. Synthesis, growth, structural, optical, thermal and mechanical properties of an organic Urea maleic acid single crystals for nonlinear optical applications

    Science.gov (United States)

    Vinothkumar, P.; Kumar, R. Mohan; Jayavel, R.; Bhaskaran, A.

    2016-07-01

    A potential organic urea maleic acid (UMA) was synthesized and single crystals were grown at room temperature by slow evaporation and seed rotation methods. The grown crystal has been subjected to single crystal XRD analysis and found to have been crystallized in a noncentrosymmetric monoclinic crystal system with Cc as space group. The High resolution X-ray diffraction analysis revealed that the specimen is free from structural grain boundaries. The transparency of the grown crystal was confirmed by optical absorption and transmittance spectra with lower cut-off wavelength of 285 nm. The microhardness test was carried out on different planes to study the load dependent hardness values. The dislocation density of the UMA crystal was estimated from the etching studies. The dielectric permittivity and dielectric loss of the grown crystal was carried out as a function of frequency for different temperatures along three crystallographic axes. Thermal properties of UMA crystals were studied by TG-DTA analysis and it is stable upto 112 °C. The laser induced surface damage threshold of the grown crystal was measured using Nd: YAG laser. The birefringence of the crystal measured in the visible region was found to vary with the wavelength. The particle size dependent SHG of the sample was measured with different input energies by Kurtz's powder method using Nd:YAG laser.

  14. Structural, optical, thermal and mechanical properties of Urea tartaric acid single crystals

    Science.gov (United States)

    Vinothkumar, P.; Rajeswari, K.; Kumar, R. Mohan; Bhaskaran, A.

    2015-06-01

    Urea tartaric acid (UT) an organic nonlinear optical (NLO) material was synthesized from aqueous solution and the crystals were grown by the slow evaporation technique. The single crystal X-ray diffraction (XRD) analysis revealed that the UT crystal belongs to the orthorhombic system. The functional groups of UT have been identified by the Fourier transform infrared spectral studies. The optical transparent window in the visible and near the IR regions was investigated. The transmittance of UT has been used to calculate the refractive index (n) as a function of the wavelength. The nonlinear optical property of the grown crystal has been confirmed by the Kurtz powder second harmonic generation test. The birefringence of the crystal was determined using a tungsten halogen lamp source. The laser induced surface damage threshold for the grown crystal was measured using the Nd:YAG laser. The anisotropic in mechanical property of the grown crystals was studied using Vicker's microhardness tester at different planes. The etch pit density of UT crystals was investigated. The thermal behavior of UT was investigated using the TG-DTA and DSC studies.

  15. Two new cobalt-zinc orthophosphate monohydrates: hydrothermal synthesis, crystal structures and thermal investigation.

    Science.gov (United States)

    Sørensen, Morten B; Hazell, Rita G; Bentien, Anders; Bond, Andrew D; Jensen, Torben R

    2005-02-07

    Two new cobalt zinc orthophosphate hydrates with similar chemical formula, (CoxZn(1-x))3(PO4)2.H2O, but different composition and structure, have been prepared by systematic hydrothermal synthesis from the system nCo(CH3COO)2 : (1 -n)Zn(CH(3)COO)2 : 3.5H3PO4 : 2.1(CH3)2NH(CH2)3NH2:144H2O (0 project. Magnetic susceptibility measurements for 1 and 2 are consistent with the chemical compositions determined by the single-crystal X-ray analyses and with the presence of Co2+. The range for possible Co/Zn substitution in 1 and 2(assessed by EDX analysis) is relatively small: x lies in the range 0.74-0.80 (+/- 0.05) for 1 and 0.23-0.28 (+/- 0.05) for 2. Thermal investigation of 1 and 2 by thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC) shows that both materials transform to gamma-(CoxZn(1-x))3(PO4)2 when heated to 518 and 435 degrees C, respectively, with enthalpy changes for complete dehydration of DeltaH= 41.9 and 53.5 kJ mol(-1), respectively. Dehydration of 1 occurs in a single irreversible step, while that of 2 occurs over a greater temperature range and proceeds via several steps. A new phase, (CoxZn(1-x))3(PO4)2.0.27H2O, is formed when 2 is heated to 357 degrees C.

  16. Crystal structure and thermal expansion of a CsCe{sub 2}Cl{sub 7} scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Zhuravleva, M., E-mail: mzhuravl@utk.edu [Scintillation Materials Research Center, University of Tennessee, Knoxville, TN (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Lindsey, A. [Scintillation Materials Research Center, University of Tennessee, Knoxville, TN (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Chakoumakos, B.C. [Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37996 (United States); Custelcean, R. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Meilleur, F. [Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Hughes, R.W.; Kriven, W.M. [Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL (United States); Melcher, C.L. [Scintillation Materials Research Center, University of Tennessee, Knoxville, TN (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States)

    2015-07-15

    We used single-crystal X-ray diffraction data to determine crystal structure of CsCe{sub 2}Cl{sub 7}. It crystallizes in a P112{sub 1}/b space group with a=19.352(1) Å, b=19.352(1) Å, c=14.838(1) Å, γ=119.87(2)°, and V=4818.6(5) Å{sup 3}. Differential scanning calorimetry measurements combined with the structural evolution of CsCe{sub 2}Cl{sub 7} via X-ray diffractometry over a temperature range from room temperature to the melting point indicates no obvious intermediate solid–solid phase transitions. The anisotropy in the average linear coefficient of thermal expansion of the a axis (21.3×10{sup –6}/°C) with respect to the b and c axes (27.0×10{sup –6}/°C) was determined through lattice parameter refinement of the temperature dependent diffraction patterns. These findings suggest that the reported cracking behavior during melt growth of CsCe{sub 2}Cl{sub 7} bulk crystals using conventional Bridgman and Czochralski techniques may be largely attributed to the anisotropy in thermal expansion. - Graphical abstract: Three-dimensional quadric surface of thermal expansion coefficient of CsCe{sub 2}Cl{sub 7} at room temperature (sphere – isotropic) and near melting point (ellipsoid – anisotropic). - Highlights: • Crystal structure of CsCe{sub 2}Cl{sub 7} was solved through X-ray diffraction. • Linear coefficients of thermal expansion were determined from in-situ XRD in 25–650 °C. • Anisotropy of the a axis with respect to b and c axes (21.3 vs 27.0×10{sup –6}/°C) was found. • No solid–solid phase transitions were observed via XRD and thermal analysis.

  17. Synthesis, growth, structural, thermal, optical properties of new metal-organic crystals: Methyltriphenylphosphonium iodide thiourea and methyltriphenylphosphonium iodide chloroform hemisolvate

    Science.gov (United States)

    Shivachev, Boris L.; Kossev, Krassimir; Dimowa, Louiza T.; Yankov, Georgi; Petrov, Todor; Nikolova, Rositsa P.; Petrova, Nadia

    2013-08-01

    Crystals of methyltriphenylphosphonium iodide thiourea (1) and methyltriphenylphosphonium iodide chloroform hemisolvate (2) were obtained for the first time. Fourier transform infrared (FTIR) spectral studies have been performed to identify the functional groups. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study their thermal properties. The optical transmittance window and the lower cutoff wavelength have been identified by UV-vis studies. Crystals of the title compounds suitable for single crystal X-ray analyses were successfully grown by slow evaporation and diffraction data were collected to elucidate the molecular structure and interactions. The proton donors (phosphonium) and proton acceptor (iodine) in the structure of 1 provide infrastructure to introduce charge asymmetry while in 2 chloroform molecule is not involved in the charge transfer. An optical quality crystal of 1 (5×4×2 mm3) was obtained by macroseeding. The crystal has developed facets with major ones (001) and (00¯1). A crystal of 1 was tested with 1060 nm laser radiation and showed second harmonic generation (SHG).

  18. Crystal structure, polymorphism, and thermal properties of yttrium borohydride Y(BH{sub 4}){sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Frommen, Christoph, E-mail: christoph.frommen@ife.n [Institute for Energy Technology, Physics Department, P.O. Box 40, NO-2027 Kjeller (Norway); Aliouane, Nadir; Deledda, Stefano; Fonnelop, Jon Erling; Grove, Hilde; Lieutenant, Klaus; Llamas-Jansa, Isabel; Sartori, Sabrina; Sorby, Magnus H.; Hauback, Bjorn C. [Institute for Energy Technology, Physics Department, P.O. Box 40, NO-2027 Kjeller (Norway)

    2010-04-30

    Y(BH{sub 4}){sub 3} was synthesized by cryo-milling mixtures of LiBH{sub 4} and YCl{sub 3} and characterized by powder X-ray and neutron diffraction (PXD, PND), differential scanning calorimetry (DSC), and temperature programmed desorption (TPD). The crystal structure was refined in the space group Pa-3 (no. 205) with lattice constant a = 10.8522(7) A from {sup 11}B and D ({sup 2}H) substituted samples using PND. It was found to contain Y{sup 3+} cations in a highly distorted octahedral environment formed by six [BD{sub 4}]{sup -} complex anions. Heat treatment under 10 MPa of deuterium at 475 K led to a phase transformation from the primitive cubic room-temperature phase to a face-centered cubic high-temperature phase with space group Fm-3c (no. 226) and lattice constant a = 11.0086(1) A. This high-temperature phase shows an ideal and undistorted octahedral coordination around the central Y{sup 3+} cation. In situ synchrotron radiation powder X-ray diffraction experiments (SR-PXD) show the presence of an intermediate phase during the thermal decomposition of Y(BH{sub 4}){sub 3} with presumably orthorhombic symmetry, and lattice constants a = 12.170(14) A, b = 7.670(5) A, and c = 7.478 (6) A, in a narrow temperature region between 473 K and 520 K.

  19. A new zinc(II supramolecular square: Synthesis, crystal structure, thermal behavior and luminescence

    Directory of Open Access Journals (Sweden)

    Wang Xiu-Yan

    2015-01-01

    Full Text Available A new square-shaped Zn(II complex, namely, [Zn4(L4(phen4]•6H2O (1 (L = 2-hydroxynicotinate and phen = 1,10- phenanthroline, has been synthesized under hydrothermal condition. The crystal of 1 belongs to triclinic, space group P -1 with a = 10.773(2 Å, b = 12.641(3 Å, c = 13.573(3 Å, α = 107.44(3º, β = 102.66(3º, γ = 93.89(3°, C72H56N12O18Zn4, Mr = 1638.77, V = 1702.8(6 Å3 , Z = 1, Dc = 1.598 g/cm3 , S = 1.045, μ(MoKα = 1.475 mm-1 , F(000 = 836, R = 0.0472 and wR = 0.0919. In 1, four L ligands bridge four Zn(II atoms to form a square-shaped structure, where four phen ligands are respectively located on four corners of the square. The π-π stacking interactions extend the adjacent squares into a 1D supramolecular chain. The thermal behavior of 1 has been characterized. Moreover, its solid state luminescence property has been studied at room temperature.

  20. Synthesis, Crystal Structure, Theoretical Calculation and Thermal Behavior of DNAZ·NTO

    Institute of Scientific and Technical Information of China (English)

    LI, Zhaona; MA, Haixia; YAN, Biao; GUAN, Yulei; SONG, Jirong

    2009-01-01

    DNAZ·NTO was prepared by mixing 3,3-dinitroazetidine (DNAZ) and 3-nitro-1,2,4-triazol-5-one (NTO) in ethanol solution. Single crystals suitable for X-ray measurement were obtained, which belong to monoclinic, space group P2_1/n with unit cell parameters of a=1.4970(4) nm, b=0.6325(2) nm, c=2.2347(7) nm, β=96.55(1)°,V=2.1022(11) nm~3, D_c=1.752 g·cm~(-3), F(000)=1136 and Z=8. Based on the analysis of the molecule structure,the theoretical investigation of the title compound was carried out at B3LYP/6-311 + +G~(**) levels, and the natural atomic charge and natural bond orbital analysis were performed. The interaction between the cation and anion was also discussed. The thermal behavior of DNAZ·NTO was carried out by DSC and TG/DTG techniques. The apparent activation energy (E_a) and pre-exponential constant (A) of the main exothermic decomposition reaction were obtained.

  1. Structural, thermal, optical and nonlinear optical properties of ethylenediaminium picrate single crystals

    Science.gov (United States)

    Indumathi, C.; T. C., Sabari Girisun; Anitha, K.; Alfred Cecil Raj, S.

    2017-07-01

    A new organic optical limiting material, ethylenediaminium picrate (EDAPA) was synthesized through acid base reaction and grown as single crystals by solvent evaporation method. Single crystal XRD analysis showed that EDAPA crystallizes in orthorhombic system with Cmca as space group. The formation of charge transfer complex during the reaction of ethylenediamine and picric acid was strongly evident through the recorded Fourier Transform Infra Red (FTIR), Raman and Nuclear Magnetic Resonance (NMR) spectrum. Thermal (TG-DTA and DSC) curves indicated that the material possesses high thermal stability with decomposition temperature at 243 °C. Optical (UV-Visible-NIR) analysis showed that the grown crystal was found to be transparent in the entire visible and NIR region. Z-scan studies with intense short pulse (532 nm, 5 ns, 100 μJ) excitations, revealed that EDAPA exhibited two photon absorption behaviour and the nonlinear absorption coefficient was found to be two orders of magnitude higher than some of the known optical limiter like Cu nano glasses. EDAPA exhibited a strong optical limiting action with low limiting threshold which make them a potential candidate for eye and photosensitive component protection against intense short pulse lasers.

  2. Structural, thermal and dielectric properties of cobaltous malonate single crystals grown in limited diffusion media

    Energy Technology Data Exchange (ETDEWEB)

    Lincy, A.; Mahalakshmi, V.; Tinto, A.J.; Thomas, J. [Smart Materials Analytic Research and Technology (SMART), Department of Physics, St. Berchmans College, Changanassery 686101, Kerala (India); Saban, K.V., E-mail: smartlabindia@gmail.co [Smart Materials Analytic Research and Technology (SMART), Department of Physics, St. Berchmans College, Changanassery 686101, Kerala (India)

    2010-11-15

    Well-faceted crystals of cobaltous malonate (C{sub 6} H{sub 12} Co{sub 2} O{sub 12}) have been grown by the controlled diffusion of ionic species in hydrosilica gel. Single crystal X-ray diffraction studies show that the crystal belongs to the monoclinic system with space group C2/m. The unit cell dimensions are a=12.6301(9) A, b=7.3857(9) A, c=7.2945(7) A, {alpha}={gamma}=90{sup o}, {beta}=120.193(9){sup o}. The functional groups, elucidated from the FT-IR spectrum, are in conformity with the information derived from the X-ray diffraction studies. The thermal behaviour of the material has been investigated using TG-DTA in the temperature range 30-1050 deg. C. The optical band gap of the sample is estimated using diffuse reflectance spectroscopy (DRS). The dielectric constant and dielectric loss of the crystal have been studied over wide temperature and frequency ranges. AC conductivity measurements reveal a thermally activated process and the mechanism behind the conduction process has been discussed.

  3. Synthesis, spectral, crystal structure, thermal behavior, antimicrobial and DNA cleavage potential of two octahedral cadmium complexes: a supramolecular structure.

    Science.gov (United States)

    Montazerozohori, M; Musavi, S A; Masoudiasl, A; Naghiha, A; Dusek, M; Kucerakova, M

    2015-02-25

    Two new cadmium(II) complexes with the formula of CdL2(NCS)2 and CdL2(N3)2 (in which L is 2,2-dimethyl-N,N'-bis-(3-phenyl-allylidene)-propane-1,3-diamine) have been synthesized and characterized by elemental analysis, molar conductivity measurements, FT/IR, UV-Visible, (1)H and (13)C NMR spectra and X-ray studies. The crystal structure analysis of CdL2(NCS)2 indicated that it crystallizes in orthorhombic system with space group of Pbca. Two Schiff base ligands are bonded to cadmium(II) ion as N2-donor chelate. Coordination geometry around the cadmium ion was found to be partially distorted octahedron. The Cd-Nimine bond distances are found in the range of 2.363(2)-2.427(2)Å while the Cd-Nisothiocyanate bond distances are 2.287(2)Å and 2.310(2)Å. The existence of C-H⋯π and C-H⋯S interactions in the CdL2(NCS)2 crystal leads to a supramolecular structure in its network. Then cadmium complexes were screened in vitro for their antibacterial and antifungal activities against two Gram-negative and two Gram-positive bacteria and also against Candida albicans as a fungus. Moreover, the compounds were subjected for DNA-cleavage potential by gel electrophoresis method. Finally thermo-gravimetric analysis of the complexes was applied for thermal behavior studies and then some thermo-kinetics activation parameters were evaluated.

  4. Synthesis, spectral, crystal structure, thermal behavior, antimicrobial and DNA cleavage potential of two octahedral cadmium complexes: A supramolecular structure

    Science.gov (United States)

    Montazerozohori, M.; Musavi, S. A.; Masoudiasl, A.; Naghiha, A.; Dusek, M.; Kucerakova, M.

    2015-02-01

    Two new cadmium(II) complexes with the formula of CdL2(NCS)2 and CdL2(N3)2 (in which L is 2,2-dimethyl-N,N‧-bis-(3-phenyl-allylidene)-propane-1,3-diamine) have been synthesized and characterized by elemental analysis, molar conductivity measurements, FT/IR, UV-Visible, 1H and 13C NMR spectra and X-ray studies. The crystal structure analysis of CdL2(NCS)2 indicated that it crystallizes in orthorhombic system with space group of Pbca. Two Schiff base ligands are bonded to cadmium(II) ion as N2-donor chelate. Coordination geometry around the cadmium ion was found to be partially distorted octahedron. The Cd-Nimine bond distances are found in the range of 2.363(2)-2.427(2) Å while the Cd-Nisothiocyanate bond distances are 2.287(2) Å and 2.310(2) Å. The existence of C-H⋯π and C-H⋯S interactions in the CdL2(NCS)2 crystal leads to a supramolecular structure in its network. Then cadmium complexes were screened in vitro for their antibacterial and antifungal activities against two Gram-negative and two Gram-positive bacteria and also against Candida albicans as a fungus. Moreover, the compounds were subjected for DNA-cleavage potential by gel electrophoresis method. Finally thermo-gravimetric analysis of the complexes was applied for thermal behavior studies and then some thermo-kinetics activation parameters were evaluated.

  5. Structural, optical, thermal, mechanical and dielectric studies of Sulfamic acid single crystals: An influence of dysprosium (Dy3+) doping

    Science.gov (United States)

    Singh, Budhendra; Shkir, Mohd.; AlFaify, S.; Kaushal, Ajay; Nasani, Narendar; Bdikin, Igor; Shoukry, H.; Yahia, I. S.; Algarni, H.

    2016-09-01

    Sulfamic acid is a potential material that exhibits excellent optical properties. A good quality, pure and dysprosium (Dy3+) doped (2.5 and 5 mol %) Sulfamic acid (SA) single crystals were grown successfully by slow cooling method. Structural study revealed a slight change in its lattice parameters and volume, suggesting the successful incorporation of Dy3+ in crystal system. The existence of dysprosium in the system was also confirmed. Presence of various vibrational modes was confirmed. Optical transparency was found to have a significant effect with variation in the doping concentration. Furthermore, a marked enhancement in its mechanical parameters with doping was also identified by nanoindentation technique. Etching study was also performed on the grown crystals to study the etch-pit formation and growth mechanism. Effect of doping on the thermal stability was analysed. All the results were compared and discussed in detail to get insight of the effect of doping concentration on Sulfamic acid crystal.

  6. Synthesis, structural, optical, thermal and dielectric studies on new organic nonlinear optical crystal by solution growth technique.

    Science.gov (United States)

    Prakash, M; Geetha, D; Lydia Caroline, M

    2013-04-15

    Single crystals of L-phenylalanine-benzoic acid (LPBA) were successfully grown from aqueous solution by solvent evaporation technique. Purity of the crystals was increased by the method of recrystallization. The XRD analysis confirms that the crystal belongs to the monoclinic system with noncentrosymmetric space group P21. The chemical structure of compound was established by FT-NMR technique. The presence of functional groups was estimated qualitatively by Fourier transform infrared analysis (FT-IR). Ultraviolet-visible spectral analyses showed that the crystal has low UV cut-off at 254 nm combined with very good transparency of 90% in a wide range. The optical band gap was estimated to be 6.91 eV. Thermal behavior has been studied with TGA/DTA analyses. The existence of second harmonic generation (SHG) efficiency was found to be 0.56 times the value of KDP. The dielectric behavior of the sample was also studied for the first time.

  7. Crystal Structures of Furazanes

    Directory of Open Access Journals (Sweden)

    Thomas M. Klapötke

    2015-09-01

    Full Text Available Several nitrogen-rich salts of 3-nitramino-4-nitrofurazane and dinitraminoazoxyfurazane were synthesized and characterized by various spectroscopic methods. The crystal structures were determined by low temperature single crystal X-ray diffraction. Moreover the sensitivities toward thermal and mechanical stimuli were determined by differential thermal analysis (DTA and BAM (Bundesanstalt für Materialforschung und -prüfung methods. The standard enthalpies of formation were calculated for all compounds at the CBS-4M level of theory, and the energetic performance was predicted with the EXPLO5 V6.02 computer code.

  8. Crystal structure, thermal and compositional deformations of {beta}-CsB{sub 5}O{sub 8}

    Energy Technology Data Exchange (ETDEWEB)

    Bubnova, R. [Institute of the Silicate Chemistry Russian Academy of Sciences, Ul. Odoevskogo, 24/2, 199155, St Petersburg (Russian Federation); Dinnebier, R.E. [Max-Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart (Germany); Filatov, S.; Anderson, J. [Saint Petersburg State University, University Emb., 7/9, 199034, St. Petersburg (Russian Federation)

    2007-02-15

    The crystal structure of {beta}-CsB{sub 5}O{sub 8} has been determined from X-ray powder diffraction data using synchrotron radiation: Pbca, a = 7.8131(3) Aa, b=12.0652(4) Aa, c=14.9582(4) Aa, Z=8, {rho}{sub calc}=2.967 g/cm{sup 3}, R-p=0.076, R-wp=0.094. {beta}-CsB{sub 5}O{sub 8} was found to be isostructural with {beta}-KB{sub 5}O{sub 8} and {beta}-RbB{sub 5}O{sub 8}. The crystal structure consists of a double interlocking framework built up from B-O pentaborate groups. The crystal structure exhibits a highly anisotropic thermal expansion: {alpha}{sub a}=53, {alpha}{sub b}=16, {alpha}{sub c}=14 .10{sup -6}/K; the anisotropy may be caused by partial straightening of the screw chains of the pentaborate groups. The similarity of the thermal and compositional (Cs-Rb-K substitution) deformations of CsB{sub 5}O{sub 8} is revealed: increasing the radius of the metal by 0.01 Aa leads to the same deformations of the crystal structure as increasing the temperature by 35 C. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Crystal structure, vibrational, spectral investigation, quantum chemical DFT calculations and thermal behavior of Diethyl [hydroxy (phenyl) methyl] phosphonate

    Science.gov (United States)

    Ouksel, Louiza; Chafaa, Salah; Bourzami, Riadh; Hamdouni, Noudjoud; Sebais, Miloud; Chafai, Nadjib

    2017-09-01

    Single Diethyl [hydroxy (phenyl) methyl] phosphonate (DHPMP) crystal with chemical formula C11H17O4P, was synthesized via the base-catalyzed Pudovik reaction and Lewis acid as catalyst. The results of SXRD analyzes indicate that this compound crystallizes into a mono-clinic system with space group P21/n symmetry and Z = 4. The crystal structure parameters are a = 9.293 Å, b = 8.103 Å, c = 17.542 Å, β = 95.329° and V = 1315.2 Å3, the structure displays one inter-molecular O-H⋯O hydrogen bonding. The UV-Visible absorption spectrum shows that the crystal exhibits a good optical transmission in the visible domain, and strong absorption in middle ultraviolet one. The vibrational frequencies of various functional groups present in DHPMP crystal have been deduced from FT-IR and FT-Raman spectra and then compared with theoretical values performed with DFT (B3LYP) method using 6-31G (p, d) basis sets. Chemical and thermodynamic parameters such as: ionization potential (I), electron affinity (A), hardness (σ), softness (η), electronegativity (χ) and electrophilicity index (ω), are also calculated using the same theoretical method. The thermal decomposition behavior of DHPMP, studied by using thermogravimetric analysis (TDG), shows a thermal stability until to 125 °C.

  10. Crystal Structures, Thermal Analysis, and Dissolution Behavior of New Solid Forms of the Antiviral Drug Arbidol with Dicarboxylic Acids

    Directory of Open Access Journals (Sweden)

    Alex N. Manin

    2015-12-01

    Full Text Available Salts of the antiviral drug arbidol (umifenovir (Arb with maleate (Mlc and fumarate (Fum anions have been obtained, and their crystal structures have been described. The crystal structure of arbidol maleate has been redetermined by single crystal X-ray diffraction at 180K. A new arbidol cocrystal in zwitterion form with succinic acid (Suc has also been found and characterized. The arbidol zwitterion was not previously seen in any of the drug crystal forms, and the [Arb + Suc] cocrystal seems to be the first found instance. Analysis of the conformational preferences of the arbidol molecule in the crystal structures has shown that it adopts two types of conformations, namely “open” and “closed” ones. Thermal stability of the arbidol salts and cocrystal have been analyzed by means of differential scanning calorimetry, thermogravimetric, and mass-spectrometry analysis. The dissolution study of the arbidol salts and cocrystal performed in aqueous buffer solutions with pH 1.2 and 6.8 has shown that both the salts and the cocrystal dissolve incongruently to form an arbidol hydrochloride monohydrate at pH 1.2 and an arbidol base at pH 6.8, respectively. The cocrystal reaches the highest solubility level in both pH 1.2 and pH 6.8 solutions.

  11. Synthesis, Crystal Structure, Fluorescent and Thermal Properties of Sodium Tridecafluorodizirconate Na5Zr2F13 Compound

    Institute of Scientific and Technical Information of China (English)

    MAO Shao-Yu; KANG You-Jun; MI Jin-Xiao; LI Man-Rong; WEI Zan-Bin; WU Xue-Yan; ZHAO Jing-Tai

    2006-01-01

    Crystals of sodium tridecafluorodizirconate Na5Zr2F13 were synthesized under mild hydrothermal conditions, and the structure was refined by single-crystal X-ray diffraction. The compound crystallizes in monoclinic with crystallographic data: Mr = 544.39, C2/m (No.12), a = 11.5600(9), b = 5.4759(4), c = 8.3989(6)(A), β= 97.361(10)°, V = 527.28(7)(A)3, Z = 2, Dc = 3.429 g/cm3, λ = 0.71073(A), μ = 23.48 cm-1, F(000) = 504, T = 295 K, R1 = 0.0173 and wR2 = 0.0449 for 55 variables and 682 contributing unique reflections. The crystal structure is constituted with six- and eight-fold sodium atoms, forming irregular trigonal prisms and irregular cubes, respectively. Here, the zirconium atoms are connected with seven fluorine atoms to form a mono-capped trigonal prism. [Zr2F13]5- complex ions formed by corner-shared [ZrF7]3- are corner- and edge- shared to [Na4F22] and [Na3F8] cages, leading to the network structure. Thermal analysis, X-ray excited luminescence and photoluminescence under UV light measurements were conducted on Na5Zr2F13 crystals.

  12. New organic single crystal of (benzylthio)acetic acid: Synthesis, crystal structure, spectroscopic (ATR-FTIR, 1H and 13C NMR) and thermal characterization

    Science.gov (United States)

    Sienkiewicz-Gromiuk, Justyna; Tarasiuk, Bogdan; Mazur, Liliana

    2016-04-01

    (Benzylthio)acetic acid (Hbta) was synthesized with 78% yield from benzyl chloride and thiourea as substrates. Well-shaped crystals of Hbta were grown by slow solvent evaporation technique from pure methanol. The compound was investigated by single-crystal X-ray and powder diffraction techniques and was also characterized by other analytical methods, like ATR-FTIR, 1H and 13C NMR and TG/DSC. The acid molecule adopts bent conformation in the solid state. The crystal structure of Hbta is stabilized by numerous intermolecular interactions, including O-H···O, C-H···O, C-H···S and C-H···π contacts. Thermal decomposition of the obtained material takes place above 150 °C.

  13. Salts of phenylacetic acid and 4-hydroxyphenylacetic acid with Cinchona alkaloids: Crystal structures, thermal analysis and FTIR spectroscopy

    Science.gov (United States)

    Amombo Noa, Francoise M.; Jacobs, Ayesha

    2016-06-01

    Seven salts were formed with phenylacetic acid (PAA), 4-hydroxyphenylacetic acid (HPAA) and the Cinchona alkaloids; cinchonidine (CIND), quinidine (QUID) and quinine (QUIN). For all the structures the proton was transferred from the carboxylic acid of the PAA/HPAA to the quinuclidine nitrogen of the respective Cinchona alkaloid. For six of the salts, water was included in the crystal structures with one of these also incorporating an isopropanol solvent molecule. However HPAA co-crystallised with quinine to form an anhydrous salt, (HPAA-)(QUIN+). The thermal stability of the salts were determined and differential scanning calorimetry revealed that the (HPAA-)(QUIN+) salt had the highest thermal stability compared to the other salt hydrates. The salts were also characterized using Fourier transform infrared spectroscopy. (PAA-)(QUID+)·H2O and (PAA-)(QUIN+)·H2O are isostructural and Hirshfeld surface analysis was completed to compare the intermolecular interactions in these two structures.

  14. Enrofloxacinium citrate monohydrate: Preparation, crystal structure, thermal stability and IR-characterization

    Science.gov (United States)

    Golovnev, Nicolay N.; Vasiliev, Alexander D.; Kirik, Sergei D.

    2012-08-01

    Enrofloxacinium citrate monohydrate (I), CHFNO3+·CHO7-·HO, [C19H22FN3O3 - enrofloxacin, EnrH] has been crystallized from the mutual solution of citric acid and enrofloxacin in ambient conditions. The colorless crystals have been investigated using X-ray single crystal and powder techniques, and characterized by differential scanning calorimetry, thermogravimetry and infrared spectroscopy. The obtained compound can be considered as a salt with enrofloxacinium in the role of a cation and citrate as an anion. The ions ratio equals to 1:1. The compound crystallizes in the triclinic lattice with a = 9.0489(8) Å, b = 9.6531(8) Å, c = 14.913(1) Å, α = 98.813(1)°, β = 92.029(1)°, γ = 91.013(1)°, Z = 2, V = 1286.1(2) Å3, S.G. P1¯. The crystal structure determination reveals the importance of inter- and intramolecular interactions in the crystal formation. The EnrH2+ and HCit molecular ions are packed in alternating layers with water molecules inserted into the citrate layers. A citrate ion in the layer is linked via H-bondings with two adjacent ones and three water molecules. Enrofloxacinium cations are packaged by means of a benched mode and every cation is linked by three intermolecular thymus type H-bondings with nitrogens of adjacent cations and by two links with the oxygen of the citrate ions. The infrared spectra gave the evidence of H-bonding formation in the obtained salt. The π-stacking interactions are observed between the aromatic cycles of the adjacent cations which are located in an antiparallel style in a layer.

  15. Crystal structure and negative thermal expansion properties of solid solution Er_2W_(3-x)Mo_xO_(12)

    Institute of Scientific and Technical Information of China (English)

    PENG Jie; LIU Xin-zhi; GUO Fu-li; HAN Song-bai; LIU Yun-tao; CHEN Dong-feng; ZHAO Xin-hua; HU Zhong-bo

    2009-01-01

    A series of solid solutions Er_2W_(3-x)Mo_xO_(12) (0.5≤x≤2.5) were successfully synthesized by the solid state method.Their crystal structures and negative thermal expansion properties were studied by high temperature X-ray powder diffraction and the Rietveld method.All samples with rare earth tungstates and molybdates crystallize in the same orthorhombic structure with space group Pnca,and show the negative thermal expansion phenomena related to transverse vibration of bridging oxygen atoms in the structure.Thermal expansion coefficients (TECs) of Er_2W_(3-x)Mo_xO_(12) were determined as -16.2×10~(-6) K~(-1) for x=0.5 and -16.5×10~(-6) K~(-1) for x=2.5 while -20.2×10~(-6) K~(-1) and -18.4×10~(-6) K~(-1) for unsubstituted Er_2W_3O_(12) and Er_2Mo_3O_(12) in the identical temperature range of 200-800 ℃.High temperature XRD data and bond length analysis suggest that the difference between W-O and Mo-O is responsible for the change of TECs after the element substitution in the series of solid solutions.

  16. Study of Growth, Structural, Thermal and Nonlinear Optical Properties of Silica Gel Grown Calcium Iodate Monohydrate Crystals

    Directory of Open Access Journals (Sweden)

    Sharda J. Shitole

    2015-12-01

    Full Text Available Single crystals of calcium iodate, monohydrate [Ca (IO32, H2O] were grown by simple gel technique by single and double diffusion method. Morphologies and habit faces like prismatic, prismatic pyramidal, needle shaped, hopper crystals were obtained. Few crystals were opaque, some were translucent and some good quality transparent crystals were obtained. EDAX spectrum verified that crystals are of calcium iodate, monohydrate indeed and was used to find Atomic % and Weight %. Unit cell parameters were obtained from the X-ray diffractogram. The calculated unit cell parameters, β, and‘d’ values are in good agreement with reported ones. Structural analysis was done by using FTIR spectroscopy which confirmed the presence of fundamental infrared frequencies, generally observed in all iodate compounds. Thermal analysis exhibits three steps explicitly on heating the samples. The first step involves dehydration at 5500C, second step shows decomposition at 5800C, and the third step involves again decomposition at 6400C. Powder second harmonic generation experiments exhibit the nonlinear nature of the substance.

  17. SYNTHESIS, THERMAL STUDIES AND CRYSTAL STRUCTURE OF 4-AMINOPYRIDINIUM SEMI-OXALATE HEMIHYDRATE

    Directory of Open Access Journals (Sweden)

    CECILIA CHACÓN

    2017-06-01

    Full Text Available The title compound has been synthesized by grinding in an agate mortar. Its structure was characterized by TGA-DSC studies and single-crystal X-ray diffraction. This compound crystallize in the monoclinic system with space group C2/c, Z = 4, and unit cell parameters a = 16.109(2 Å, b = 5.748(7 Å, c = 20.580(3 Å, β = 107.36(1°. The salt, C2HO4-.C5H7N+.0.5 H2O, is an ionic ensemble assisted by hydrogen bonds established between 4-aminopyridinium cations, oxalate anions and water molecules. The three components thus construct a supramolecular assembly with a three-dimensional hydrogen bonded framework.

  18. Crystal structure, electrical conductivity and thermal expansion of Ni and Nb co-doped LaCoO3.

    Science.gov (United States)

    Øygarden, Vegar; Grande, Tor

    2013-02-28

    The effect of co-doping LaCoO(3) with Ni and Nb has been investigated in the two solid solution series (1 - x)LaCoO(3)-xLaNi(2/3)Nb(1/3)O(3) and (1 - y)LaCo(2/3)Ni(1/3)O(3)-yLaNi(2/3)Nb(1/3)O(3). The materials were shown to be stoichiometric with respect to oxygen. The compositional effect on the evolution of the crystal structure, thermal expansion and electrical conductivity is reported. The chemical stability of LaCoO(3) in a reducing atmosphere was improved and the thermal expansion was suppressed at higher levels of Nb-substitution. The materials with mixed oxidation states on the B-site possessed superior electrical transport properties compared to solid solutions with cations in mainly isovalent oxidation states. The evolution of the electronic conductivity, thermal expansion and crystal structural is discussed with emphasis on the oxidation states of Ni and Co, and the spin transitions of Co.

  19. Synthesis, crystal structure, thermal analysis and dielectric properties of two mixed trichlorocadmiates (II)

    Indian Academy of Sciences (India)

    ABDESSATTAR BEN CHRIFA; ABDELHAMID BEN SALAH; MOHAMED LOUKIL

    2016-09-01

    K$_{0.57}$(NH$_4$)$_{0.43}$CdCl$_3$ and K$_{0.25}$(NH$_4$)$_{0.75}$CdCl$_3$ are orthorhombic, space group Pnma, $Z = 4$, with $a = 8.8760(4)$ $\\AA$, $b = 3.9941(2)$ $\\AA$, $c = 14.7004(7)$ $\\AA$, and $Z = 4$, $a = 8.9567(9)$ $\\AA$, $b = 3.9957(4)$ $\\AA$, $c = 14.855(2)$ $\\AA$, respectively. Final R values are 0.01 and 0.02 for 608 and 834 reflections, respectively. In both the materials, the crystal structure has been determined by X-ray single crystal analysis at room temperature (293 K). The compound structures consist of K$^+$ (or NH$^+_4$) cations and double chains of CdCl$_6$ octahedra sharing one edge extending along $b$-axis. The mixture of KA$^+$/NH$^+_4$ cations are located between the double chains ensuring the stability of the structure by ionic and hydrogen bonding contacts N/K–H$\\ldots$ Cl. Spectroscopic, dielectric and differential scanning calorimetry(DSC) measurements were performed to discuss the mechanism of the phase transition. These studies show that these materials, K$_{0.57}$(NH$_4$)$_{0.43}$CdCl$_3$ and K$_{0.25}$(NH$_4$)$_{0.75}$CdCl$_3$, undergo a phase transition at 438 and 454 K, respectively.

  20. Investigation of thermal evolution of nanodomain structures in nonlinear barium sodium niobate crystals

    Institute of Scientific and Technical Information of China (English)

    S.V.Ivanova

    2008-01-01

    By the 90°elastic light scattering investigation and far field observation in the range of 20-800℃,the relation between behavior of light scattering anomalies and evolution of nanodomain structures in lattice of barium sodium niobate(Ba2NaNb5O15,BSN)crystal was clarified.The correlation between anomalies on the temperature curves of the elastic light scattering intensity and temperature transformations of nanodomains was studied by X-ray and electron microscope methods.Phase transition near 500℃ and movement in field of scattering light could be explained by appearance of a new incommensurate phase.

  1. Synthesis, Crystal Structure, Thermal Decomposition and Sensitivity Properties of (AIM)(HTNR) and (AIM)(PA)

    Institute of Scientific and Technical Information of China (English)

    TANG Zhan; YANG Li; QIAO Xiao-jing; WU Bi-dong; ZHANG Tong-lai; ZHOU Zun-ning; YU Kai-bei

    2012-01-01

    Two new energetic compounds (AIM)(HTNR) and (AIM)(PA)(AIM=2-azidoimidazole,TNR=2,4,6-trinitroresorcinol,PA=picric acid) have been prepared by AIM(2-azidoimidazolium) and TNR(2,4,6-trinitroresorcinol) or PA(picric acid) and characterized by elemental analysis and FTIR spectrum.Their crystal structures were determined by X-ray single-crystal diffraction analysis.The obtained results show that (AIM)(HTNR) crystal belongs to monoclinic,P2(1)/c space group,a=1.1306(2) nm,b=0.70305(14) nm,c=1.7398(4) nm,β=106.91°,V=1.3231(5) nm3,Dc=1.778 g/cm3,Z=4,R1=0.0524,wR2[I>2σ(I)]=0.1067 and S=1.092 and (AIM)(PA) crystal belongs to monoclinic P21/c space group,a=0.80303(16) nm,b=0.81395(16) nm,c=2.0471(4) nm,β=93.93(3)°,V=1.3349(5) nm3,Dc=1.683g/cm3,Z=4,R1=0.0784,wR2[I>2σ(I)]=0.1814 and S=1.098.Both the compounds have electrostatic attraction and hydrogen bonds,which contribute to making the constructions more stable.The decomposition of the two compounds was studied via differential scanning calorimetry(DSC) and thermogravimetry-derivative thermogravimetry(TG-DTG)techniques at a heating rate of 10 ℃/min,and the results show that both the compounds underwent one intensive exothermic decomposition stage.Sensitivity tests reveal that the title compounds were insensitive to friction and impact and sensitive to flame and could be applied in potential pyrotechnics.

  2. Crystal structure and thermal stability of martensite in Cu-25Al-3Mn alloy

    Institute of Scientific and Technical Information of China (English)

    李周; 汪明朴; 曹玲飞; 徐根应; 苏玉长

    2002-01-01

    The martensite structure in Cu-25Al-3Mn alloy and its thermal cycling and aging behavior are studied. It is convinced that the M2H martensite can be obtained by water-quenched, and the atoms distribution on the basal plane of the mart ensite is: Ⅰ(corner)-Al; Ⅱ(center of the plane)-Cu; Ⅲ(middle of b- side)-22/25Cu+3/25Mn. The lattice parameters are determined to be a=0.445 9 nm, b=0.527 9 nm, c=0.424 1 nm, β=88.64°. The triangle and other complicated configurations consisting of the variant group in the martensite are discovered. It is showed that the tested alloy has a high thermal stability when aging at average temperature in the parent phase, and the thermoelastic martensite amount is up to 90% af ter aging for 96 hat 400 ℃. The thermal cycling has a little influence on the transform ation temperature (Ms). When the number of thermal cycles is up to 1000, the increasing of Ms is only 8 ℃.

  3. Synthesis, crystal structure, spectroscopic, thermal and dielectric properties of a novel semi-organic pentachloroantimonate (III)

    Science.gov (United States)

    Lahbib, Ikram; Rzaigui, Mohamed; Smirani, Wajda

    2016-09-01

    A new organic-inorganic hybrid material of formula (C10H15N2F)5(SbCl5)5.2H2O was synthesized and characterized by X-Ray diffraction analysis. It crystallizes in the monoclinic space group P21/c with the following unit cell parameters a = 15.819(4) Å, b = 17.685(3) Å, c = 30.529(4) Å, Z = 4 and V = 8540(3) Å3. The examination of the structure shows that the three-dimensional frameworks are produced by Nsbnd H⋯Cl, Nsbnd H⋯O, Csbnd H⋯Cl and Nsbnd H⋯F, Csbnd H⋯F hydrogen bonding and Cl⋯Cl interactions. IR, Raman and UV-Visible spectroscopies were also used to characterize this compound. In addition, the fluorescent properties of this compound have been investigated in the liquid state at room temperature. Differential scanning calorimetry (DSC) has revealed a structural phase transition of the order-disorder type around 370 K. Dielectric investigations revealed a step-wise change of the electric permittivity at Ttr characteristic of the crystal in the high-temperature phase. The evolution of dielectric constant as a function of temperature of the sample has been investigated in order to determine some related parameters. Measurements of AC conductivity as a function of frequency at different temperatures indicated a hopping conduction mechanism and/or reorientational motion.

  4. Crystal structure and thermal decomposition mechanism of the supramolecular complex of barium chloride with inositol

    Institute of Scientific and Technical Information of China (English)

    WANG; Feili; TANG; Zongxun; LI; Shuni; HU; Daodao; ZHAO; Ho

    2005-01-01

    The single crystal of [Ba(H2O)2(C6H12O6)2Cl2] was obtained based on the phase equilibrium results. Its structure was determined by X-ray crystallographic analysis. The crystals are monoclinic and in space group C2/c with a = 1.901 7(2) nm, b = 0.682 13(8) nm, c = 0.162 60(2) nm, β = 96.593(2)° and V = 2.095 3(4) nm3, Z = 4, DC = 1.917 g·cm-3. In its solid state, this supramolecular complex is a three-dimensional network with double layers connected by hydrogen bondings. The molecule structure of [Ba(H2O)2(C6H12O6)2Cl2] has a central barium ion that is coordinated to two water molecules, two chlorides, and four hydroxyls from the two inositols. Losing the coordinating water is controlled by random nucleation and growth mechanism (n = 2/3) and 3-dimensional diffusion mechanism (n = 2).

  5. Theoretical investigation on crystal structure, detonation performance and thermal stability of a high density cage hexanitrohexaazaisowurtzitane derivative

    Indian Academy of Sciences (India)

    Li Xiao-Hong; Cui Hong-Ling; Li Li-Ben; Zhang Xian-Zhou

    2013-07-01

    Density functional theory calculations were performed to study the new polynitro cage compound with the similar framework of HNIW. IR spectrum, heat of formation and thermodynamic properties were predicted. The bond dissociation energies and bond orders for the weakest bonds were analysed to investigate the thermal stability of the title compound. The detonation and pressure were evaluated by using the Kamlet-Jacobs equations based on the theoretical density and condensed HOFs. In addition, the results show that there exists an essentially linear relationship between the WBIs of N-NO2 bonds and the charges -QNO2 on the nitro groups. The crystal structure obtained by molecular mechanics belongs to P21/C space group, with lattice parameters Z = 4, a = 12.3421 Å, b = 24.6849 Å, c = 20.4912 Å, = 1.896 g cm-3. The designed compound has high thermal stability and good detonation properties and is a promising high energy density compound.

  6. Crystal structure, Hirshfeld surface analysis, vibrational, thermal behavior and UV spectroscopy of (2,6-diaminopyridinium) dihydrogen arsenate

    Science.gov (United States)

    Bouaziz, Emna; Ben Hassen, Chawki; Chniba-Boudjada, Nassira; Daoud, Abdelaziz; Mhiri, Tahar; Boujelbene, Mohamed

    2017-10-01

    A new organic dihydrogenomonoarsenate (C5H8N3)H2AsO4 was synthesized by slow evaporation method at room temperature and characterized by X-ray single crystal diffraction. This compound crystallizes in the monoclinic system with the centro-symmetric space group P21/n. Unit cell parameters are a = 10.124 (5)Ǻ, b = 6.648 (5)Ǻ, c = 13.900 (5)Ǻ, β = 105.532° with Z = 4. The crystal structure was solved and refined to R = 0.038 with 2001 independent reflections. Hirshfeld surfaces analysis were used to visualize the fidelity of the crystal structure which has been determined by X-ray data collection on single crystals (C5H8N3)H2AsO4. Due the strong hydrogen Osbnd H⋯O bond network connecting the H2AsO4 groups, the anionic arrangement must be described as infinite (H2AsO4)nn-of dimers chains spreading, in a zig zag fashion, parallel to the b direction. The organic groups (C5H8N3)+ are anchored between adjacent polyanions through multiple hydrogen bonds Nsbnd H⋯O. The thermal decomposition of precursors studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), indicate the existence of two mass loss regions correspond to degradation of the title compound. The existence of vibrational modes correspond to the organic and inorganic groups are identified by the infrared and Raman spectroscopy in the frequency ranges 500-4000 and 25-4000 cm-1, respectively.

  7. A Novel Catenarian Cyano(triphenyl phosphite) Copper(Ⅰ) Complex: Synthesis, Crystal Structure, Thermal, Voltammetric and Spectral Properties

    Institute of Scientific and Technical Information of China (English)

    QIAO,Yuan-Biao; WANG,Ke-Fei; HU,Li-Hong; JIAN,Fang-Fang

    2006-01-01

    Quantitative reaction between copper(Ⅰ) cyanide and triphenyl phosphite forms copper(Ⅰ) complex [(P(OPh)3)4Cu4(CN)4] (1). X-Ray crystal structure shows a catenarian polymer of tandem interconnected copper cyanide, with C and N connecting to proximal Cu atoms. The Cu atoms adopt two different conformations: one exhibits linear construction, while the other exhibits distorted tetrahedral geometry through coordinating to two cyano groups and the P donors of triphenyl phosphite molecules. The feature of 1 is the propagation pattern of two- and four-coordination along with the chain. IR and electronic absorption spectra also confirm the established single crystal structure. Thermal analysis indicates that 1 has a high thermal stability. 3-D fluorescence result shows the middle absorption peaks with the maximum excitement and emission wavelength 342 and 350 nm, respectively.Cyclic voltammogram in DMSO, DMF and MeCN gives a midpoint voltage of -0.003, 0.061 and 0.137 V versus SCE, respectively, showing the different solvent virtue on reduction potential.

  8. 3β-Acetoxy-6-nitrocholest-5-ene: Crystal structure, thermal, optical and dielectrical behavior

    Science.gov (United States)

    Shamsuzzaman; Mashrai, Ashraf; Khanam, Hena; Mabkhot, Yahia Nasser; Frey, Wolfgang

    2014-04-01

    3β-Acetoxy-6-nitrocholest-5-ene (2) has been synthesized from 3β-acetoxycholest-5-ene (1). We provided an analysis of the compound by means of FT-IR, FT-Raman, NMR and X-ray crystallography. In addition microstructural, thermal, optical and dielectrical properties were also investigated. The compound 2 crystallizes in the monoclinic space group P21 with cell dimensions, a = 15.7729 (13) Å, b = 9.8933 (8) Å, c = 17.8070(14) Å, α = 90.00, β = 96.176(4), γ = 90.00. The powder X-ray diffraction (PXRD) of the compound was recorded to ascertain phase homogeneity. The SEM micrograph showed the presence of brick shaped, elongated nitrocholestane particles with 177.12 × 25.53 × 5.69 μm dimensions. Thermogravimetric analysis showed stability of the compound up to 200 °C. The dielectrical studies showed that with increase in frequency, the dielectric constant decreases and becomes almost constant at high frequencies.

  9. Thermal diode made by nematic liquid crystal

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-07

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

  10. Crystalline structures, thermal properties and crystallizing mechanism of polyamide 6 nanotubes in confined space

    Science.gov (United States)

    Li, Xiaoru; Peng, Zhi; Yang, Chao; Han, Ping; Song, Guojun; Cong, Longliang

    2016-09-01

    The polyamide 6 (PA6) nanotubes were prepared by infiltrating the anodic aluminum oxide templates with polymer solution. Crystalline regions in the nanotube walls were detected by high-resolution transmission electron microscopy (HRTEM). X-ray diffraction (XRD), Fast Fourier Transform (FFT) and differential scanning calorimetry (DSC) techniques were employed to investigate crystallization, crystal faces and thermodynamics. It was found that the crystals were transformed from α-form in bulk to γ-form in nanotubes. It was made a detailed analysis in this article. Moreover, schematic diagram for the crystallizing mechanism of PA6 nanotubes was given to explain PA6 molecules how to crystallize in the nano-pores.

  11. Nitrogen-rich 6-(3,5-Dimethylpyrazol-1-yl)-3-(2,4,6-trinitroanilino)-1,2,4,5-tetrazin: Synthesis, Crystal Structure and Thermal Property

    Institute of Scientific and Technical Information of China (English)

    PAN, Wan-Long; HUANG, Kun-Lin; TANG, Wang; XU, Yan-Qing; HU, Chang-Wen

    2007-01-01

    6-(3,5-Dimethylpyrazol-1-yl)-3-(2,4,6-trinitroanilino)-1,2,4,5-tetrazin (1) has been synthesized and characterized by 1H NMR, MS, elemental analysis, infrared spectra and thermal analyses. The crystal structure was determined by X-ray diffraction method. 1 is crystallized in P21/c space group of monoclinic crystal system, and exhibits good physical properties, such as high densities (> 1.55 g·cm-3) and good thermal stabilities (Td>220 ℃). The intrermolecular hydrogen bonds construct the P- and M-helices from organic molecules and may contribute to the high melting points.

  12. Synthesis, X-ray Crystal Structure and Thermal Decomposition Mechanism of [RbHTNR]∞

    Institute of Scientific and Technical Information of China (English)

    ZHENG, Hong; ZHANG, Tong-Lai; ZHANG, Jian-Guo; QIAO, Xiao-Jing; YANG, Li; YU, Kai-Bei

    2006-01-01

    A new compound, [RbHTNR]∞ [HTNR-: C6H(NO2)3(OH)O ], was synthesized by the reaction of rubidium nitrate and styphnic acid. The molecular structure was characterized using X-ray diffraction analysis, elemental analysis and FTIR spectroscopy. The crystalline is monoclinic with space group P21/n and the empirical formula C6H2N3OsRb. The unit cell parameters are: a=0.4525 nm, b=1.0777 nm, c= 1.9834 nm, β=90.47(2)°, V=0.96725 nm3, Z=4, Dc=2.263 g/cm3, Mr=329.58, F(000)=640, μ(Mo Kα)=5.165 mm-1. The thermal decomposition mechanism of the complex was studied by differential scanning calorimetry (DSC), thermogravimetryderivative thermogravimetry (TG-DTG) and FTIR techniques. At the linear rate of 10 ℃/min, the thermal decomposition of the complex showed three mass reducing processes between 60 and 500 ℃, and finally evolved RbCN and some gaseous products.

  13. Hydrothermal Synthesis, Crystal Structure and Thermal Analysis of a Dinuclear Complex Cd2(3,5-Dinitrobenzoate)4(pyridine)4

    Institute of Scientific and Technical Information of China (English)

    GUO Jin-Yu; ZHANG Tong-Lai; ZHANG Jian-Guo; LIU Yan-Hong; QIAO Xiao-Jing; YANG Li

    2006-01-01

    A dinuclear complex Cd2(dnba)4(pyridine)4 (dnba = 3,5-dinitrobenzoate) has been synthesized by hydrothermal method and characterized by X-ray single-crystal diffraction, elemen- tal analysis, FT-IR spectroscopy, DSC and TG-DTG techniques. The complex with empirical formula C48H32Cd2N12O24 (Mr = 692.83) crystallizes in monoclinic, space group P21/n with a = 12.0344(14), b = 10.5752(13), c = 21.578(3) (A), β = 104.150(2)o, V = 2662.8(6) (A)3, Z = 2, Dc = 1.728 g/cm3, μ(MoKα) = 0.897 mm-1, F(000) = 1384, S = 1.016 and (Δ/σ)max = 0.001. R = 0.0638 and wR = 0.0737 for all data; the final R = 0.0337 and wR = 0.0644. In this complex, four carboxylates are bidentate- or chelate-coordinated with the Cd(Ⅱ) centers to give the dinuclear structure. The other coordination positions of Cd(Ⅱ) are occupied by the lone pair electrons from N of four pyridines. Thermal analyses DSC and TG-DTG have been used to determine the thermal decomposition mechanism of the title complex.

  14. Synthesis, Crystal Structure, Thermal Decomposition and Sensitive Properties of a New Complex [Cu(IMI)4](PA)2

    Institute of Scientific and Technical Information of China (English)

    WANG Shi-wei; WU Bi-dong; YANG Li; ZHANG Tong-lai; ZHOU Zun-ning; ZHANG Jian-guo

    2012-01-01

    A new coordination complex [Cu(IMI)4](PA)2 had been synthesized with imidazole(IMI) as ligands and picrate(PA ) groups as outer anions,and characterized by Fourier transform infrared(FTIR) spectrum and elemental analysis.Its crystal structure was determined by single crystal X-ray diffraction(XRD) analysis.The crystallographic data show that the crystal belongs to monoclinic,C2/c space group,a=2.542(5) nm,b=0.91773(18) nm,c=1.3778(3)nm,β=107.854(3)° and Z=4.Furthermore,the central copper(Ⅱ) ion is coordinated by four N atoms from four imidazole ligands.All the molecular units are linked into a zigzag pattern along a-axis by the hydrogen bonds,and extended to the distance regularly.Thermal decomposition mechanisms were determined based on differential scanning calorimetry(DSC) and thermogravimetry-diff.erential thermogravimetry(TG-DTG) analysis,and kinetic parameters of the first exothermic process were studied using Kissinger's and Ozawa-Doyle's method,respectively.Sensitivity tests show that the title complex has low sensitivity to external stimulus,but it has a higher energy of combustion of 14.2kJ/g due to which it may be used as the additives of energetic materials to improve the explosive performance.

  15. Synthesis, structural, thermal, mechanical, second harmonic generation efficiency and laser damage threshold studies of 4-dimethylaminopyridinium-3,5-dicarboxybenzoate trihydrate single crystal

    Science.gov (United States)

    Rajkumar, M.; Saravanabhavan, M.; Chandramohan, A.

    2017-10-01

    4-dimethylaminopyridinium-3,5-dicarboxybenzoate trihydrate was synthesized and single crystals grown by slow solvent evaporation solution growth technique at ambient temperature. The single crystal XRD analysis was carried out to establish the molecular structure of the title crystal. Further, the data indicate that the title salt crystallizes in orthorhombic crystal system with the non-centrosymmetric space group, Pna21. The established molecular structure was further confirmed by 1H and 13C NMR spectroscopic studies. The grown crystal has been subjected to FT-IR spectral study to identify the various functional groups. The UV-Vis-NIR transmission spectrum was recorded on powdered sample of crystal to determine the lower wavelength cut-off and optical band gap. The photoluminescence spectrum was recorded to investigate the luminescence properties of the salt crystal. The thermal and mechanical stabilities of the crystal were established by TG/DTA analyses and Vickers microhardness study, respectively. The dielectric studies of the grown crystal were executed at different temperatures as a function of frequency to investigate its electrical properties. The SHG efficiency of the title crystal was investigated and its value is 0.89 times that of KDP crystal. The laser damage threshold value is found to be 1.06 GW/cm2.

  16. Crystal structure and prediction.

    Science.gov (United States)

    Thakur, Tejender S; Dubey, Ritesh; Desiraju, Gautam R

    2015-04-01

    The notion of structure is central to the subject of chemistry. This review traces the development of the idea of crystal structure since the time when a crystal structure could be determined from a three-dimensional diffraction pattern and assesses the feasibility of computationally predicting an unknown crystal structure of a given molecule. Crystal structure prediction is of considerable fundamental and applied importance, and its successful execution is by no means a solved problem. The ease of crystal structure determination today has resulted in the availability of large numbers of crystal structures of higher-energy polymorphs and pseudopolymorphs. These structural libraries lead to the concept of a crystal structure landscape. A crystal structure of a compound may accordingly be taken as a data point in such a landscape.

  17. Two new heterodinuclear Schiff base complexes: synthesis, crystal structure and thermal studies.

    Science.gov (United States)

    Yardan, Alper; Hopa, Cigdem; Yahsi, Yasemin; Karahan, Ahmet; Kara, Hulya; Kurtaran, Raif

    2015-02-25

    Two new heterodinuclear Schiff base complexes, [Hg(L)NiCl2(DMF)2] 1, and [Zn(L)NiCl2(DMF)2] 2, where H2L = N,N'-bis(salicylidene)-1,3-diaminopropane and DMF = dimethylformamide have been synthesized and characterized using elemental analysis, IR spectroscopy, thermal analysis and X-ray diffraction. Structural studies on 1 and 2 reveal the presence of a heterodinuclear [Ni(II)Hg(II)] unit and [Zn(II)Ni(II)] in which the central metal ions are connected to each other by two phenolate oxygen bridges. For complex 1 the Ni(II) ion adopts an elongated octahedral geometry (NiN2O4) while the Hg(II) ion assumes a distorted tetrahedral arrangement (HgO2Cl2) whereas for complex 2 the Zn(II) ion adopts an elongated octahedral geometry (ZnN2O4) while the Ni(II) ion assumes a distorted tetrahedral arrangement (NiO2Cl2). There are intermolecular C-H···Cl-M interactions among the dinuclear complexes which are interconnected for 1 and 2. These intermolecular interactions result in the formation of a three dimensional structure for 1 and one dimensional zig-zag chains for 2.

  18. Thermal diode made by nematic liquid crystal

    Science.gov (United States)

    Melo, Djair; Fernandes, Ivna; Moraes, Fernando; Fumeron, Sébastien; Pereira, Erms

    2016-09-01

    This work investigates how a thermal diode can be designed from a nematic liquid crystal confined inside a cylindrical capillary. In the case of homeotropic anchoring, a defect structure called escaped radial disclination arises. The asymmetry of such structure causes thermal rectification rates up to 3.5% at room temperature, comparable to thermal diodes made from carbon nanotubes. Sensitivity of the system with respect to the heat power supply, the geometry of the capillary tube and the molecular anchoring angle is also discussed.

  19. Crystal Structure and Thermal Decomposition Mechanism of [K(DNP)(H2O)0.5]n

    Institute of Scientific and Technical Information of China (English)

    MA, Gui-Xia(马桂霞); ZHANG, Tong-Lai(张同来); ZHANG, Jian-Guo(张建国); SHAO, Bing(邵兵); LI, Yu-Feng(李玉锋); SONG, Jiang-Chuang(宋江闯); YU, Kai-Bei(郁开北)

    2004-01-01

    The new coordination polymer, [K(DNP)(H2O)0.5]n (DNP=2,4-dinitrophenol) was prepared by the reaction of 2,4-dinitrophenol with potassium hydroxide. The molecular structure was determined by X-ray single-crystal diffraction analysis, FT-IR techniques, and elemental analysis. The crystal is monoclinic, space group C(2)/c with the empirical formula of C6H4N2O5.5K, Mr=231.21. The unit cell parameters are as follows: a=2.0789(3) nm, b=1.2311(2) nm, c=0.7203(1) nm, β=109.611(15)°, V=1.7366(4) nm3, Z=4, Dc=1.769 g/cm3, F(000)=936, μ (Mo Kα)=0.617 mm-1. The potassium ions coordinate with all the oxygen atoms of phenolic hydroxyl group and nitro-group of different 2,4-dinitrophenol (DNP) ligands with high coordination number, and form a good cross-linked three-dimensional net structure of which makes the complex with good stabilities. The thermal decomposition of [K(DNP)(H2O)0.5]n has only an intense exothermic process in the temperature range of 338-343 ℃ corresponding to a mass loss of 75.02%. The final decomposition residue is potassium isocyanide.

  20. [MII(NCS)2(nia)2(OH2)2]: Preparation, Crystal Structure and Thermal Properties (MII = Mn, Fe; nia = nicotinamide).

    Science.gov (United States)

    Počkaj, Marta; Kitanovski, Nives; Čeh, Boris; Cerc-Korošec, Romana

    2017-06-01

    Two novel isostructural coordination compounds of manganese(II) (1) and iron(II) (2) with common formulae [MII(NCS)2(nia)2(OH2)2] have been prepared from water solution of appropriate metal salt, nicotinamide and KSCN. Their crystal structures were determined by means of X-ray diffraction on single crystals. The mononuclear title compounds crystallize in a triclinic P-1 space group with six monodentate octahedrally arranged ligands around the metal centre. The coordination molecules are self-assembled with an extended network of hydrogen bonds into a three-dimensional structure. Additionally, 1 and 2 were characterized with infrared spectroscopy, magnetic measurements and thermal analysis.

  1. Growth, structural, spectral, mechanical, thermal and dielectric characterization of phosphoric acid admixtured L-alanine (PLA) single crystals

    Science.gov (United States)

    Rose, A. S. J. Lucia; Selvarajan, P.; Perumal, S.

    2011-10-01

    Phosphoric acid admixtured L-alanine (PLA) single crystals were grown successfully by solution method with slow evaporation technique at room temperature. Crystals of size 18 mm × 12 mm × 8 mm have been obtained in 28 days. The grown crystals were colorless and transparent. The solubility of the grown samples has been found out at various temperatures. The lattice parameters of the grown crystals were determined by X-ray diffraction technique. The reflection planes of the sample were confirmed by the powder X-ray diffraction study and diffraction peaks were indexed. Fourier transform infrared (FTIR) studies were used to confirm the presence of various functional groups in the crystals. UV-visible transmittance spectrum was recorded to study the optical transparency of grown crystal. The nonlinear optical (NLO) property of the grown crystal was confirmed by Kurtz-Perry powder technique and a study of its second harmonic generation efficiency in comparison with potassium dihydrogen phosphate (KDP) has been made. The mechanical strength of the crystal was estimated by Vickers hardness test. The grown crystals were subjected to thermo gravimetric and differential thermal analysis (TG/DTA). The dielectric behavior of the sample was also studied.

  2. Phenylacetic acid co-crystals with acridine, caffeine, isonicotinamide and nicotinamide: Crystal structures, thermal analysis, FTIR spectroscopy and Hirshfeld surface analysis

    Science.gov (United States)

    Amombo Noa, Francoise M.; Jacobs, Ayesha

    2017-07-01

    Co-crystals of phenylacetic acid (PAA) with acridine (ACR), caffeine (CAF), isonicotinamide (INM) and nicotinamide (NAM) have been successfully prepared and characterised by single crystal X-ray diffraction, FTIR spectroscopy, thermal analysis and Hirshfeld surface analysis. The ACR, INM and NAM co-crystals with PAA exhibit the carboxylic acid-pyridine heterosynthon. Furthermore the amide-amide supramolecular homosynthon is observed in the PAA co-crystals with INM and NAM as well as Nsbnd H⋯O interactions between the acid and the respective base. The CAF co-crystal exhibits hydrogen bonding between the imidazole nitrogen and the COOH group of the PAA. The compounds demonstrate different stoichiometries; for PAA·ACR and PAA·INM a 1:1 ratio is displayed, a 2:1 in 2PAA·CAF and a 2:2 in the case of 2PAA·2NAM.

  3. Anion-tuned self-assembly of zinc(II) fluconazole complexes: Crystal structures, luminescent and thermal properties

    Science.gov (United States)

    Zhang, Lei; Ling, Yun; Peng, Feng; Du, Miao

    2007-03-01

    Four novel fluconazole-bridged Zn(II) complexes, [Zn(HFlu)Cl 2(DMF)] 2 ( 1), {[Zn(HFlu) 2(H 2O) 2](NO 3) 2·2DMF} n ( 2), {[Zn(HFlu) 2(H 2O) 2](NO 3) 2} n ( 3) and {[Zn(HFlu)(SCN) 2]·H 2O} n ( 4) [HFlu = 2-(2,4-difluorophenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol], have been synthesized and structurally characterized by X-ray diffraction method. The structure of dimeric complex 1 consists of 20-membered macrometallacyclic ring-like structure, in which the Zn(II) ion is in a five-coordinated distorted trigonal bipyramidal geometry with the Zn⋯Zn distance of 10.265(3) Å across the cis HFlu ligand. Complex 2 shows infinite 1-D macrocyclic double chain structure with the central Zn(II) ions being six-coordinated by four HFlu ligands and two apical water molecules and with the intrachain Zn⋯Zn distance of 10.722(3) Å across the trans HFlu ligand. The crystal structure of complex 3 is analogous to that of complex 2 with the intrachain Zn⋯Zn distance of 10.654(2) Å. The structure of complex 4 consists of infinite 1-D coordination polymeric chain with the tetrahedral coordination geometry of Zn(II) ion and with the intrachain Zn⋯Zn distance of 11.173(2) Å across the cis HFlu ligand. Complexes 1- 4 show the similar fluorescence emission to the free HFlu ligand at ambient temperature and the thermal stabilities of the complexes have also been investigated.

  4. Growth, structural, optical, thermal and mechanical properties of cytosinium hydrogen selenite: A novel nonlinear optical single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Jaikumar, P. [PG & Research Department of Physics, National College (Autonomous), Tiruchirappalli, 620 001 Tamil Nadu (India); Sathiskumar, S. [Crystal Growth Laboratory, Department of Physics, Periyar EVR College (Autonomous), Tiruchirappalli, 620 023 Tamil Nadu (India); Balakrishnan, T., E-mail: balacrystalgrowth@gmail.com [Crystal Growth Laboratory, Department of Physics, Periyar EVR College (Autonomous), Tiruchirappalli, 620 023 Tamil Nadu (India); Ramamurthi, K. [Crystal Growth & Thin Film laboratory, Department of Physics & Nanotechnology, SRM University, Kattankulathur, 603 203 Kancheepuram, Tamil Nadu (India)

    2016-06-15

    Highlights: • Growth of bulk single crystals of cytosinium hydrogen selenite (CHS) is reported. • Dielectric constant of CHS is measured as a function of Frequency and temperature. • Lower cut off value of UV–vis-NIR spectrum of CHS crystal is observed at 210 nm. • Meyer’s index value of CHS crystal calculated identifies it as a soft material. • Powder SHG efficiency of CHS is about 1.5 times that of KDP crystal. - Abstract: A novel nonlinear optical single crystal of cytosinium hydrogen selenite was grown from aqueous solution of cytosinium hydrogen selenite by slow solvent evaporation method at room temperature. The structural properties of grown crystal have been studied by single crystal and powder X-ray diffraction analysis. Presence of various functional groups was identified from Fourier transform infrared spectroscopy. The optical transmittance and absorbance spectra were recorded by UV–vis-NIR spectrometer and the grown crystal possesses good transparency in the entire visible region. The dielectric constant and dielectric loss of the crystal were calculated as a function of frequency at different temperatures. The mechanical strength of the cytosinium hydrogen selenite crystal was estimated using Vicker’s microhardness tester. Etch patterns of the cytosinium hydrogen selenite crystal were obtained using distilled water as etchant for different etching time. Second harmonic generation efficiency tested using Nd:YAG laser is about 1.5 times that of KDP.

  5. 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).

  6. 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).

  7. Synthesis, Crystal Structures, Thermal Analysis and Magnetic Property of Mono- and Bi-nuclear 1,1-Cyclobutanedicarboxylate Copper Complexes

    Institute of Scientific and Technical Information of China (English)

    LI, Ming-Xing; DAI, Hui; SHAO, Min; SHI, Lei; LIN, Kun-Hua; CHENG, Zhi-Xuan; WENG, Lin-Hong

    2006-01-01

    Two new copper complexes, [Cu(cbdc)(phen)(H2O)]·2H2O (1) and [Cu2(cbdc)(phen)2(H2O)2](ClO4)2·H2O (2)(cbdc= 1,1-cyclobutanedicarboxylate and phen= 1,10-phenanthroline), were synthesized by reaction of cbdc with Cu(ClO4)2 and phen in ethanol aqueous solution. Complex 1 crystallizes in monoclinic system with space group P2(1)/c and a=0.9428(4) nm, b= 1.2183(5) nm, c= 1.6265(7) nm, β= 102.418(5)°, V= 1.8246(13) nm3, Z=4, R=3D supramolecular structure where Cu(Ⅱ) ion is five-coordinated and has square-pyramidal coordination geometry.Its thermal decomposition procedure detail was studied by thermal analysis TG-DSC. Complex 2 belongs to monoclinic system with space group P2(1)/c and a=0.8897(3) nm, b= 1.9130(8) nm, c= 1.9936(8) nm, β=99.04(2)°,V=3.351(2) nm3, Z=4, R=0.0540, wR2=0.1102. The structure of 2 is a discrete binucleus, where Cu(1) is four-coordinated by phen and cbdc in a square-planar geometry while Cu(2) is five-coordinated by phen, one O of cbdc and two H2O, which can be best described as distorted trigonal-bipyramidal geometry. Cu(1) and Cu(2) are linked by carboxylic group of cbdc in a bidentate bridging fashion. Variable-temperature magnetic susceptibilities of 2 in 2-300 K showed that its magnetic behavior obeyed Curie law.

  8. Growth,structural,thermal properties and spectroscopic characteristics of KTb(WO4)2 single crystal

    Institute of Scientific and Technical Information of China (English)

    LI Jing; WANG Jiyang; HAN Shujuan; GUO Yongjie; WANG Yongzheng

    2012-01-01

    KTb(WO4)2(KTW) single crystal with dimensions up to 30 mm×30 mm×10 mm was grown by the top-seeded solution growth (TSSG) method for the first time.The crystal structure was refined at room temperature by using single crystal X-ray diffraction data.Absorption and fluorescence spectra were measured at room temperature.The fluorescence lifetime of KTb(WO4)2 was 114 μs.The specific heat of the KTb(WO4)2 crystal was also measured at room temperature.

  9. Synthesis, Crystal Structure and Thermal Analysis of N-(2,3-Dimethyl-phenyl)-N′-(methoxyl formyl)thiourea

    Institute of Scientific and Technical Information of China (English)

    ZHAO Dan; HUANG Jie; SONG Ji-rong; ZHONG Yi-tang; WANG Li-qin; HE Jian-yun

    2012-01-01

    N-(2,3-Dimethyl-phenyl)-N′-(methoxyl formyl)thiourea was synthesized by the reacting of 2,3-dimethy-laniline,potassium thiocyanate(KSCN)and methyl chloroformate(C1COOCH3).Single crystal was obtained by slowly evaporation solvent at room temperature.The structure was characterized by elemental analysis,IR and X-ray crystalography.The compound crystallized:a triclinic system with space group P(i),a=0.83440(12)nm,b=0.89113(13)nm,c=0.93015(13)nm,a=76.548(2)°,β=63.906(2)°,γ=82.538(2)°,V=0.60379(15)nm3,Z=2,Dc=1.311 mg/m3,F(000)=252,μ=0.256 mm-1,R1=0.0379,wR2=0.0919.The specific heat capacity of the title compound was determined by a Micro-DSC method,and the specific heat capacity was 1.25 J·g-1·K-1 at 298.15 K.Thermodynamic functions,relative to those at the standard temperature of 298.15 K,were calculated via thermodynamic relationship.The thermal behavior of the title compound under a non-isothermal condition was studied by differential scanning calorimetry/thermogravimetric(DSC/TG)method.There was an obvious endothermic peak in the DSC curve,the peak temperature was 479.43 K.The compound mass loss was 89.94% observed from the TG curve.

  10. The thermal physical properties and structure of In-In2Bi eutectic at melting-crystallization process

    Directory of Open Access Journals (Sweden)

    V. Prokhorenko

    2007-04-01

    Full Text Available The physical properties of In-In2Bi liquid eutectic alloy as well as structure has been studied at different temperature. Structure data are used for calculation of configuration entropy. The change of structure upon melting is analyzed in comparison with change chemical bonding. The data on acoustic emission studies at meting and crystallization processes are analyzed too.

  11. Synthesis, growth, morphology of the semiorganic nonlinear optical crystal L-glutamic acid hydrochloride and its structural, thermal and SHG characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Dhanasekaran, P.; Srinivasan, K. [Crystal Growth Laboratory, Department of Physics, School of Physical Sciences, Bharathiar University, Coimbatore-641 046, Tamil Nadu (India)

    2012-12-15

    One of the halide derivatives of L-glutamic acid which was identified as a semiorganic nonlinear optical material, L-glutamic acid hydrochloride [HOOC(CH{sub 2}){sub 2}CH(NH{sub 2})COOH.HCl], was grown as bulk single crystal and its significant properties were characterized. The stoichiometric title compound was synthesized and the solubility of its recrystallized form in DD water was determined in the temperature range 30-80 C by gravimetric method. Structural confirmation was carried out by powder X-ray diffraction study through lattice parameter verification. Optical quality smaller dimension single crystals were grown from aqueous solution by self nucleation through slow evaporation of solvent method and a large dimension single crystal was grown by slow cooling method with reversible seed rotation technique. Morphological importances of different growth facets of the as grown crystals were studied through optical goniometry. Unit cell structure of the grown crystal was refined by single crystal X-ray diffraction analysis, functional groups present in the crystal responsible for various modes of vibrations were confirmed by FTIR spectroscopy analysis, thermal stability of the grown crystal was analysed by TG/DTA and DSC and second harmonic generation (SHG) of a fundamental Nd:YAG laser beam by Kurtz technique. Results indicate that the grown crystal is in stoichiometric composition and has significant improvement in its thermal and SHG properties when compared to pure L-glutamic acid polymorphs. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Synthesis, X-ray crystal structures and thermal analyses of some new antimicrobial zinc complexes: New configurations and nano-size structures.

    Science.gov (United States)

    Masoudiasl, A; Montazerozohori, M; Naghiha, R; Assoud, A; McArdle, P; Safi Shalamzari, M

    2016-04-01

    Some new five coordinated ZnLX2 complexes, where L is N3-Schiff base ligand obtained by condensation reaction between diethylenetriamine and (E)-3-(2-nitrophenyl)acrylaldehyde and X (Cl(-), Br(-), I(-), N3(-) and NCS(-)), were synthesized and characterized by FT-IR, (1)H and (13)CNMR, UV-visible, ESI-mass spectra and molar conductivity measurements. The structures of zinc iodide and thiocyanate complexes were determined by X-ray crystallographic analysis. The X-ray results showed that the Zn (II) center in these complexes is five-coordinated in a distorted trigonal-bipyramidal configuration. Zinc iodide and thiocyanate complexes crystallize in the monoclinic and triclinic systems with space groups of C2/c and P1- with eight and two molecules per unit cell respectively. The crystal packing of the complexes consists of intermolecular interactions such as C-H(…)O and C-H(…)I, C-H(···)S, N(…)O, together with π-π stacking and some other unexpected interactions. The mentioned interactions cause three-dimensional supramolecular structure in the solid state. Zinc complexes were also prepared in nano-structure by sonochemical method confirmed by XRD, SEM and TEM analyses. Moreover, ZnO nanoparticles were synthesized by direct thermolysis of zinc iodide complex. Furthermore, antimicrobial and thermal properties of the compounds were completely investigated.

  13. 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.

  14. Tris(dithiocarboxylato)indium(III): Thermal studies and crystal structure of [In(S2Ctol)3

    Indian Academy of Sciences (India)

    Shamik Ghoshal; Nisha P Kushwah; Manoj K Pal; Vimal K Jain; Munirathinam Nethaji

    2008-05-01

    Tris(dithiocarboxylato)indium(III), [In{S2CAr}3] (Ar = phenyl or -tolyl) have been synthesized and characterized. The molecular structure of [In(S2Ctol)3] established by single crystal X-ray diffraction revealed a distorted octahedral geometry with symmetrically chelating dithiocarboxylate groups. These complexes on thermolysis gave -In2S3 which was characterized by XRD and EDX.

  15. 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.

  16. CRYSTAL STRUCTURE, ELECTRICAL CONDUCTIVITY AND THERMAL EXPANSION OF Pr1-xSrxFeO3-δ(0 ≤ x ≤ 0.6)

    Science.gov (United States)

    Prashanth Kumar, V.; Reddy, Y. S.; Kistaiah, P.; Vishnuvardhan Reddy, C.

    2012-12-01

    The crystal structure at room temperature (RT), thermal expansion from RT to 1000°C and electrical conductivity, from RT to 600°C, of the perovskite-type oxides in the system Pr1-xSrxFeO3(x = 0, 0.2, 0.4, 0.6) were studied. All the compounds have the orthorhombic perovskite GdFeO3-type structure with space group Pbnm. The lattice parameters were determined by X-ray powder diffraction. The Pseudo cubic lattice parameter decreases with an increase in x, while the coefficient of linear thermal expansion increases. The thermal expansion is almost linear for x = 0 and 0.2. The electrical conductivity increases with increasing x while the activation energy decreases. The electrical conductivity can be described by the small polaron hopping conductivity model.

  17. Thermal expansion behavior of empressite, AgTe: A structural study by means of in situ high-temperature single-crystal X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Bindi, Luca [Museo di Storia Naturale, sez. di Mineralogia, Universita di Firenze, Via La Pira 4, I-50121 Firenze (Italy)], E-mail: luca.bindi@unifi.it

    2009-04-03

    The crystal structure of empressite, AgTe, a rare silver telluride, has been investigated by in situ X-ray single-crystal diffraction methods within the temperature range 298-463 K. AgTe remains orthorhombic, space group Pmnb (Pnma as standard), and shows only normal thermal expansion over the entire temperature range. The unit-cell parameters show a gradual increase with the increase of temperature. Slight adjustments in the geometry of Ag-tetrahedra and in the crystal-chemical environment of tellurium atoms occur in a continuous way without abrupt structural changes. The coefficients of thermal expansion along various axes are: {alpha}{sub a} = 1.5 x 10{sup -5} K{sup -1}, {alpha}{sub b} = 3.0 x 10{sup -5} K{sup -1}, {alpha}{sub c} = 2.2 x 10{sup -5} K{sup -1}, and the bulk thermal expansion coefficient {alpha}{sub V} is 5.4 x 10{sup -5} K{sup -1} for the temperature range 298-463 K.

  18. Anhydrous lithium borate, Li{sub 3}B{sub 11}O{sub 18}, crystal structure, phase transition and thermal expansion

    Energy Technology Data Exchange (ETDEWEB)

    Sennova, Natalia [Techinsche Univ. Darmstadt (Germany). Eduard-Zintl-Inst. fuer Anorganische und Physikalische Chemie; St. Petersburg State Univ. (Russian Federation). Dept. of Crystallographie; Albert, Barbara [Techinsche Univ. Darmstadt (Germany). Eduard-Zintl-Inst. fuer Anorganische und Physikalische Chemie; Bubnova, Rimma [St. Petersburg State Univ. (Russian Federation). Dept. of Crystallographie; Russian Academy of Science, St. Petersburg (Russian Federation). Inst. of Silicate Chemistry; Krzhizhanovskaya, Maria; Filatov, Stanislav [St. Petersburg State Univ. (Russian Federation). Dept. of Crystallographie

    2014-10-01

    A new lithium borate, Li{sub 3}B{sub 11}O{sub 18}, was synthesized by crystallization from glass, containing an excess of B{sub 2}O{sub 3}. The compound crystallizes monoclinic, P2{sub 1}/a, Z=4, a=9.766(5) Aa, b=7.849(5) Aa, c=17.899(9) Aa, β=100.96(5) circle, V=1347.0(13) Aa{sup 3} (R=0.06, wR=0.12). The structure is based upon two interpenetrating frameworks formed by triborate and pentaborate groups. The thermal behaviour of Li{sub 3}B{sub 11}O{sub 18} was studied using DTA, DSC, and high-temperature XRD. Highly anisotropic thermal expansion and a new high-temperature phase were observed.

  19. 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.

  20. Growth, structural, optical, thermal and dielectric properties of a novel semi-organic nonlinear optical crystal: Dichloro-diglycine zinc II

    Directory of Open Access Journals (Sweden)

    B. Uma

    2014-08-01

    Full Text Available Dichloro-diglycine zinc II (DCDGZ II, a semi-organic nonlinear optical material has been synthesized and single crystals were grown from the aqueous solution up to dimensions 20×10×3 mm3. The title compound, DCDGZ II (C4H10Cl2N2O4Zn·H2O crystallizes into monoclinic structure with the space group of C2/c. The unit-cell parameters were found to be a=14.4191(7, b=6.9180(2, c=12.9452(6 Å and Z=4. In the crystal structure, DCDGZ II layer is building up alternatingly with layers of water in which the zinc ions lie on a twofold axis. Theoretical calculations for polarizability, which are useful for device fabrication were made using Clausius–Mosotti equation and Penn analysis and the results were compared. Fourier transform infrared (FTIR spectroscopic studies were performed for the identification of the different functional groups presented in the compound. The UV–vis–NIR absorption spectrum reveals that the lower UV cut-off wavelength is 240 nm. The optical band gap of the crystal was estimated as 2.2 eV. The surface morphology, thermal behaviour, dielectric properties have been studied using SEM, TG/DTA and LCR HITESTER analyzer. The nonlinear optical property of the crystal was also confirmed using Kurtz powder technique.

  1. Crystal structures and thermal expansion properties of Y2-xErxMo4O15 (x = 0.0-2.0) solid solutions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new series of rare earth compounds, Y2-xErxMo4O15 (x = 0.0-2.0), were synthesized and their structures were determined by powder X-ray diffraction (XRD). Rietveld analysis of XRD patterns reveals that the compounds of this series crystallize in monoclinic system with space group P21/c. The lattice parameters a, b, c, β and the unit cell volume V decrease linearly with increasing Er content. The thermal expansion properties of these compounds were studied under high-temperature XRD. Positive thermal expansions of compounds Y2-xErxMo4O15 are found to be anisotropic along the three crystallographic directions where a and c axes expand while b axis contracts in the whole temperature range. By analysis of data, the expansion of weak band Mo2-O14 with rising temperature should be responsible for positive thermal expansion.

  2. Hydrothermal Synthesis, Crystal Structure and Thermal Properties of a Novel Samarium Complex with 1D Nano-chain Structure

    Institute of Scientific and Technical Information of China (English)

    LI Ya-Juan; LIANG Qing; SONG Hui-hua; JIA Mi-ying; SHI Shi-Kao; ZHANG Jian-jun

    2009-01-01

    @@ 1 Introduction The design and construction of metal-organic polymers has been a field of rapid growth in materials chemistry because of their intriguing topologies and potential applications as functional materials[1-6]. In this regard, every effort has been devoted to the deli-berate design and control of self-assembly infinite coordination networks via selecting the chemistry structures of ligands. Multidentate carboxylate ligands are widely adopted for construction of coordination frameworks due to their rich coordination modes[7-13].

  3. Tris dithiocarbamate of Co(III) complexes: Synthesis, characterization, thermal decomposition studies and experimental and theoretical studies on their crystal structures

    Science.gov (United States)

    Sonia, Ayyavoo Sait; Bhaskaran, Ramalingam

    2017-04-01

    New homoleptic complexes of the form [Co(L1)3] & [Co(L2)3] where L1 = (ethylaminoethanol dithiocarbamate) 1 and L2 = (methylaminoethanol dithiocarbamate) 2 have been prepared and characterized by elemental analysis, IR, UV-visible absorption spectra, Cyclic voltammetry,1H and C13 NMR. The thermal properties were studied using a simultaneous thermal analyzer, and showed two main steps of decomposition. In addition, structures for 1 and 2 have been elucidated by X-ray crystallography. The single-crystal X-ray analysis for both the complexes showed distorted octahedral geometry. The optimized molecular structure, natural bond orbital analysis, electrostatic potential map, HOMO-LUMO energies, molecular properties, and atomic charges of these molecules have been studied by performing DFT/B3LYP/6-31G(d,p) level of theory in gas phase.

  4. A novel coordination polymer of Ni(II) based on 1,3,5-benzenetricarboxylic acid synthesis, characterization, crystal structure, thermal study, and luminescent properties

    Science.gov (United States)

    Saheli, Sania; Rezvani, Alireza

    2017-01-01

    A new metal-organic framework (MOF) formulated as [Ni(H2btc)(OH)(H2O)2] (1) (H3btc = 1,3,5-benzenetricarboxylic acid) was synthesized using the hydrothermal technique. The complex 1 was characterized by elemental analysis, infrared spectroscopy, and powder X-ray diffraction in addition to single crystal X-ray diffraction. X-ray crystal structural analysis displayed that the compound belonged to the monoclinic space group P21/n with cell parameters a = 6.8658(14) Å, b = 18.849(4) Å, c = 8.5608(17) Å. In the title complex, ligand is linked to metal centers through two μ-oxo bridges and forming a 2D layer which is led to form an interesting geometry. The thermal stability and fluorescence property of 1 have also been investigated.

  5. Thermal Expansion Coefficients of Thin Crystal Films

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The formulas for atomic displacements and Hamiltonian of a thin crystal film in phonon occupation number representation are obtained with the aid of Green's function theory. On the basis of these results, the formulas for thermal expansion coefficients of the thin crystal film are derived with the perturbation theory, and the numerical calculations are carried out. The results show that the thinner films have larger thermal expansion coefficients.

  6. Self-assembled supramolecular structure of 1-methyl piperazinium 4-nitrophenolate 4-nitrophenol monohydrate single crystal: Synthesis, growth, thermal and photo physical properties.

    Science.gov (United States)

    Nagapandiselvi, P; Baby, C; Gopalakrishnan, R

    2015-08-05

    A new photoactive organic crystal, 1-methyl piperazinium 4-nitrophenolate-4-nitrophenol monohydrate (MP4NPM) has been synthesised at 35 °C. Good quality single crystals of MP4NPM have successfully been grown by slow evaporation solution growth technique. Single crystal X-ray diffraction analysis shows that MP4NPM belongs to monoclinic crystal system with space group P2₁/n. The molecular structure was further confirmed by modern spectroscopic techniques like FT-NMR (both 1D and 2D), FT-IR, UV-Vis-NIR and fluorescence. The UV-Vis-NIR spectrum was performed to understand the range of optical transparency and the results showed its suitability for nonlinear optical applications. Fluorescence emission revealed that MP4NPM can serve as a photo active material. Thermal properties of MP4NPM were investigated using simultaneous TG-DSC analysis. Frequency and temperature dependent dielectric properties were studied in the frequency range 500 Hz-5 MHz and 40-50 °C, respectively. Vicker's microhardness measurements revealed that MP4NPM belongs to the category of soft material. Kurtz and Perry powder technique shows that MP4NPM has SHG efficiency 0.89 times that of potassium dihydrogen phosphate (KDP). Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Self-assembled supramolecular structure of 1-methyl piperazinium 4-nitrophenolate 4-nitrophenol monohydrate single crystal: Synthesis, growth, thermal and photo physical properties

    Science.gov (United States)

    Nagapandiselvi, P.; Baby, C.; Gopalakrishnan, R.

    2015-08-01

    A new photoactive organic crystal, 1-methyl piperazinium 4-nitrophenolate-4-nitrophenol monohydrate (MP4NPM) has been synthesised at 35 °C. Good quality single crystals of MP4NPM have successfully been grown by slow evaporation solution growth technique. Single crystal X-ray diffraction analysis shows that MP4NPM belongs to monoclinic crystal system with space group P21/n. The molecular structure was further confirmed by modern spectroscopic techniques like FT-NMR (both 1D and 2D), FT-IR, UV-Vis-NIR and fluorescence. The UV-Vis-NIR spectrum was performed to understand the range of optical transparency and the results showed its suitability for nonlinear optical applications. Fluorescence emission revealed that MP4NPM can serve as a photo active material. Thermal properties of MP4NPM were investigated using simultaneous TG-DSC analysis. Frequency and temperature dependent dielectric properties were studied in the frequency range 500 Hz-5 MHz and 40-50 °C, respectively. Vicker's microhardness measurements revealed that MP4NPM belongs to the category of soft material. Kurtz and Perry powder technique shows that MP4NPM has SHG efficiency 0.89 times that of potassium dihydrogen phosphate (KDP).

  8. Structure, surface area and morphology of aluminas from thermal decomposition of Al(OH(CH3COO2 crystals

    Directory of Open Access Journals (Sweden)

    KIYOHARA PEDRO K.

    2000-01-01

    Full Text Available Crystalline aluminium hydroxiacetate was prepared by reaction between aluminium powder (ALCOA 123 and aqueous solution of acetic acid at 96ºC ±1ºC. The white powder of Al(OH(CH3COO2 is constituted by agglomerates of crystalline plates, having size about 10mum. The crystals were fired from 200ºC to 1550ºC, in oxidizing atmosphere and the products characterized by X-ray diffraction, scanning electron microscopy and surface area measurements by BET-nitrogen method. Transition aluminas are formed from heating at the following temperatures: gamma (300ºC; delta (750ºC; alpha (1050ºC. The aluminas maintain the original morphology of the Al(OHAc2 crystal agglomerates, up to 1050ºC, when sintering and coalescence of the alpha-alumina crystals start and proceed up to 1550ºC. High surface area aluminas are formed in the temperature range of 700ºC to 1100ºC; the maximum value of 198m²/g is obtained at 900ºC, with delta-alumina structure. The formation sequence of transition aluminas is similar to the sequence from well ordered boehmite, but with differences in the transition temperatures and in the development of high surface areas. It is suggested that the causes for these diversities between the two sequences from Al(OH Ac2 and boehmite are due to the different particle sizes, shapes and textures of the gamma-Al2O3 which acts as precursor for the sequence gamma- to alpha-Al2O3.

  9. Supramolecular architectures in luminescent Zn(II) and Cd(II) complexes containing imidazole derivatives: Crystal structures, vibrational and thermal properties, Hirshfeld surface analysis and electrostatic potentials

    Science.gov (United States)

    Di Santo, Alejandro; Echeverría, Gustavo A.; Piro, Oscar E.; Pérez, Hiram; Ben Altabef, Aida; Gil, Diego M.

    2017-04-01

    Three novel zinc and cadmium complexes with 1-methylimidazole and 2-methylimidazole as ligands, mono-nuclear dichloro-bis(1-methylimidazole) zinc(II) and dibromo-bis(2-methylimidazole)cadmium(II) monohydrate complexes, and poly-nuclear bis(1-methylimidazole)-di-(μ2-bromo)cadmium(II) complex, namely, compounds 1-3, respectively, have been synthesized. The complexes were characterized by IR and Raman spectroscopies, thermal analysis and fluorescence. All the compounds exhibit interesting luminescent properties in solid state originated from intra-ligand (π→π*) transitions. Crystal structures of 1-3 were determined by single-crystal X-ray diffraction. Compound 1 crystallizes in P21/n space group, the Zn(II) ion lies at a crystal general position in a tetrahedral environment, and the mono-nuclear units are weakly bonded to one another by Csbnd H⋯Cl hydrogen bonds. Compound 2 crystallizes in Pnma space group, and mirror-related tetrahedral units around Cd(II) ion are H-bonded through a water molecule. Compound 3 crystallizes in P21/c space group, and the Cd(II) ion presents a centrosymmetric octahedral coordination. Neighboring and equatorial edge-sharing octahedra conform a polymeric arrangement that extends along the crystal a-axis. Weak hydrogen bonds are the major driving forces in the crystal packing of the three complexes. Hirshfeld surface analysis reveals a detailed scrutiny of intermolecular interactions experienced by each complex. The surfaces mapped over dnorm property highlight the X···H (X = Cl, Br) as the main intermolecular contacts for the three complexes, being also relevant the presence of O⋯H contacts for complex 2. The surfaces mapped over Shape index and curvedness properties for the two Cd complexes allow identify π … π stacking interactions which are absent in the Zn complex. 2D fingerprint plots have been used to quantify the relative contribution of the intermolecular contacts to crystal stability of compounds, showing

  10. Synthesis, Crystal Structure and Thermal Stability of 1D Linear Silver(I Coordination Polymers with 1,1,2,2-Tetra(pyrazol-1-ylethane

    Directory of Open Access Journals (Sweden)

    Evgeny Semitut

    2016-10-01

    Full Text Available Two new linear silver(I nitrate coordination polymers with bitopic ligand 1,1,2,2-tetra(pyrazol-1-ylethane were synthesized. Synthesized compounds were characterized by IR spectroscopy, elemental analysis, powder X-ray diffraction and thermal analysis. Silver coordination polymers demonstrated a yellow emission near 500 nm upon excitation at 360 nm. Crystal structures of coordination polymers were determined and structural peculiarities are discussed. In both of the structures, silver ions are connected via bridging ligand molecules to form polymeric chains with a five-atomic environment. The coordination environment of the central atom corresponds to a distorted trigonal bipyramid with two N atoms of different ligands in apical positions. The Ag–N bond distances vary in a wide range of 2.31–2.62 Å, giving strongly distorted metallacycles. Thermolysis of coordination polymers in reductive atmosphere (H2/He leads to the formation of silver nanoparticles with a narrow size distribution.

  11. The crystal structure of paramagnetic copper(II) oxalate (CuC₂O₄): formation and thermal decomposition of randomly stacked anisotropic nano-sized crystallites.

    Science.gov (United States)

    Christensen, Axel Nørlund; Lebech, Bente; Andersen, Niels Hessel; Grivel, Jean-Claude

    2014-11-28

    Synthetic copper(II) oxalate, CuC2O4, was obtained in a precipitation reaction between a copper(II) solution and an aqueous solution of oxalic acid. The product was identified from its conventional X-ray powder patterns which match that of the copper mineral Moolooite reported to have the composition CuC2O4·0.44H2O. Time resolved in situ investigations of the thermal decomposition of copper(II) oxalate using synchrotron X-ray powder diffraction showed that in air the compound converts to Cu2O at 215 °C and oxidizes to CuO at 345 °C. Thermo gravimetric analysis performed in an inert Ar-gas reveals that the material contains no crystal water and reduces to pure Cu at 295 °C. Magnetic susceptibility measurements in the temperature range from 2 K to 300 K show intriguing paramagnetic behaviour with no sign of magnetic order down to 2 K. A crystal structure investigation is made based on powder diffraction data using one neutron diffraction pattern obtained at 5 K (λ = 1.5949(1) Å) combined with one conventional and two synchrotron X-ray diffraction patterns obtained at ambient temperature using λ = 1.54056, 1.0981 and λ = 0.50483(1) Å, respectively. Based on the X-ray synchrotron data the resulting crystal structure is described in the monoclinic space group P2₁/c (#14) in the P12₁/n1 setting with unit cell parameters a = 5.9598(1) Å, b = 5.6089(1) Å, c = 5.1138 (1) Å, β = 115.320(1)°. The composition is CuC2O4 with atomic coordinates determined by FullProf refinement of the neutron diffraction data. The crystal structure consists of a random stacking of CuC2O4 micro-crystallites where half the Cu-atoms are placed at (2a) and the other half at (2b) positions with the corresponding oxalate molecules centred around the corresponding (2b) and (2a) site positions, respectively. The diffraction patterns obtained for both kinds of radiation show considerable broadening of several Bragg peaks caused by highly anisotropic microstructural size and strain

  12. Remarkable reduction of thermal conductivity in phosphorene phononic crystal.

    Science.gov (United States)

    Xu, Wen; Zhang, Gang

    2016-05-05

    Phosphorene has received much attention due to its interesting physical and chemical properties, and its potential applications such as thermoelectricity. In thermoelectric applications, low thermal conductivity is essential for achieving a high figure of merit. In this work, we propose to reduce the thermal conductivity of phosphorene by adopting the phononic crystal structure, phosphorene nanomesh. With equilibrium molecular dynamics simulations, we find that the thermal conductivity is remarkably reduced in the phononic crystal. Our analysis shows that the reduction is due to the depressed phonon group velocities induced by Brillouin zone folding, and the reduced phonon lifetimes in the phononic crystal. Interestingly, it is found that the anisotropy ratio of thermal conductivity could be tuned by the 'non-square' pores in the phononic crystal, as the phonon group velocities in the direction with larger projection of pores is more severely suppressed, leading to greater reduction of thermal conductivity in this direction. Our work provides deep insight into thermal transport in phononic crystals and proposes a new strategy to reduce the thermal conductivity of monolayer phosphorene.

  13. Thermal expansion accompanying the glass-liquid transition and crystallization

    Directory of Open Access Journals (Sweden)

    M. Q. Jiang

    2015-12-01

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

  14. Crystal structures, thermal expansion and phase transitions of mixed Pr{sub 1-x}La{sub x}AlO{sub 3} perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Basyuk, Tetyana; Vasylechko, Leonid [Lviv Polytechnic National University (Ukraine); Syvorotka, Igor [SRC, Carat, Lviv (Ukraine); Schmidt, Ulrike [Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany); Trots, Dmytro [HASYLAB, DESY, Hamburg (Germany); Niewa, Rainer [Technische Universitaet Muenchen, Garching (Germany)

    2009-05-15

    The crystal structures, thermal expansion and phase transitions of mixed Pr{sub 1-x}La{sub x}AlO{sub 3} perovskites have been examined by using an in situ high resolution X-ray powder diffraction technique applying synchrotron radiation in a wide temperature range of 12-1173 K. At room temperature all samples in the PrAlO{sub 3}-LaAlO{sub 3} pseudo-binary system adopt the rhombohedral perovskite-like structure. At elevated temperatures, all Pr{sub 1-x}La{sub x}AlO{sub 3}compositions undergo continuous phase transitions from rhombohedral to cubic structures. The sequence of the low-temperature (LT) phase transformations R anti 3 c<->Imma<->C2/m has been observed in Pr{sub 1-x}La{sub x}AlO{sub 3} samples. Temperatures of HT and LT phase transitions in Pr{sub 1-x}La{sub x}AlO{sub 3}decrease with decreasing Pr content. Crystal structure parameters for all compositions Pr{sub 1-x}La{sub x}AlO{sub 3} have been determined. Based on in situ powder diffraction and DTA/DSC data, the phase diagram of the PrAlO{sub 3}-LaAlO{sub 3}pseudo-binary system has been constructed. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. The crystal structure, vibrational spectra, thermal behaviour and second harmonic generation of aminoguanidinium(1+) hydrogen L-tartrate monohydrate

    Science.gov (United States)

    Macháčková, Zorka; Němec, Ivan; Teubner, Karel; Němec, Petr; Vaněk, Přemysl; Mička, Zdeněk

    2007-04-01

    Aminoguanidinium(1+) hydrogen L-tartrate monohydrate was prepared by crystallisation from aqueous solution and X-ray structural analysis was carried out. The substance crystallises in the orthorhombic system in space group P2 12 12 1, a = 7.1380(2) Å, b = 9.9700(4) Å, c = 14.0790(6) Å, V = 1001.94(7) Å 3, Z = 4, R = 0.0271 for 2272 observed reflections. The crystal structure consists of a 3D framework formed by hydrogen tartrate anions and water molecules with incorporated aminoguanidinium(1+) cations connected by a system of hydrogen bonds. The FTIR and FT Raman spectra of natural and N,O-deuterated compounds were measured and discussed at laboratory temperature. DSC measurements were carried out in the temperature range from 95 to 380 K. A weak anomaly was observed at a temperature of 268 K. Quantitative measurements of second harmonic generation of powdered aminoguanidinium(1+) hydrogen tartrate monohydrate at 800 nm were performed relative to KDP and a relative efficiency of 14% was observed.

  16. 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.

  17. Terahertz radiation induces non-thermal structural changes associated with Fröhlich condensation in a protein crystal.

    Science.gov (United States)

    Lundholm, Ida V; Rodilla, Helena; Wahlgren, Weixiao Y; Duelli, Annette; Bourenkov, Gleb; Vukusic, Josip; Friedman, Ran; Stake, Jan; Schneider, Thomas; Katona, Gergely

    2015-09-01

    Whether long-range quantum coherent states could exist in biological systems, and beyond low-temperature regimes where quantum physics is known to be applicable, has been the subject to debate for decades. It was proposed by Fröhlich that vibrational modes within protein molecules can order and condense into a lowest-frequency vibrational mode in a process similar to Bose-Einstein condensation, and thus that macroscopic coherence could potentially be observed in biological systems. Despite the prediction of these so-called Fröhlich condensates almost five decades ago, experimental evidence thereof has been lacking. Here, we present the first experimental observation of Fröhlich condensation in a protein structure. To that end, and to overcome the challenges associated with probing low-frequency molecular vibrations in proteins (which has hampered understanding of their role in proteins' function), we combined terahertz techniques with a highly sensitive X-ray crystallographic method to visualize low-frequency vibrational modes in the protein structure of hen-egg white lysozyme. We found that 0.4 THz electromagnetic radiation induces non-thermal changes in electron density. In particular, we observed a local increase of electron density in a long α-helix motif consistent with a subtle longitudinal compression of the helix. These observed electron density changes occur at a low absorption rate indicating that thermalization of terahertz photons happens on a micro- to milli-second time scale, which is much slower than the expected nanosecond time scale due to damping of delocalized low frequency vibrations. Our analyses show that the micro- to milli-second lifetime of the vibration can only be explained by Fröhlich condensation, a phenomenon predicted almost half a century ago, yet never experimentally confirmed.

  18. Terahertz radiation induces non-thermal structural changes associated with Fröhlich condensation in a protein crystal

    Directory of Open Access Journals (Sweden)

    Ida V. Lundholm

    2015-09-01

    Full Text Available Whether long-range quantum coherent states could exist in biological systems, and beyond low-temperature regimes where quantum physics is known to be applicable, has been the subject to debate for decades. It was proposed by Fröhlich that vibrational modes within protein molecules can order and condense into a lowest-frequency vibrational mode in a process similar to Bose-Einstein condensation, and thus that macroscopic coherence could potentially be observed in biological systems. Despite the prediction of these so-called Fröhlich condensates almost five decades ago, experimental evidence thereof has been lacking. Here, we present the first experimental observation of Fröhlich condensation in a protein structure. To that end, and to overcome the challenges associated with probing low-frequency molecular vibrations in proteins (which has hampered understanding of their role in proteins' function, we combined terahertz techniques with a highly sensitive X-ray crystallographic method to visualize low-frequency vibrational modes in the protein structure of hen-egg white lysozyme. We found that 0.4 THz electromagnetic radiation induces non-thermal changes in electron density. In particular, we observed a local increase of electron density in a long α-helix motif consistent with a subtle longitudinal compression of the helix. These observed electron density changes occur at a low absorption rate indicating that thermalization of terahertz photons happens on a micro- to milli-second time scale, which is much slower than the expected nanosecond time scale due to damping of delocalized low frequency vibrations. Our analyses show that the micro- to milli-second lifetime of the vibration can only be explained by Fröhlich condensation, a phenomenon predicted almost half a century ago, yet never experimentally confirmed.

  19. Crystal structure, DNA interaction and thermal analysis data of two new antimicrobial active binuclear cadmium and mercury complexes

    Science.gov (United States)

    Musavi, S. A.; Montazerozohori, M.; Masoudiasl, A.; Naghiha, R.; Joohari, S.; Assoud, A.

    2017-10-01

    Two new binuclear Schiff base complexes with the general formula [CdLBr(μ-Br)]2 (1) and [Hg2L(μ-I)2I2] (2) were prepared by the reaction of 2,2-dimethyl-N,N'- bis-(3-phenyl-allylidene)-propane-1,3-diamine (L), CdBr2 and HgI2. The crystal structure of two complexes was determined by X-ray crystallography. The common structures for four-coordinated compounds are square planar or the tetrahedral geometries, which is evaluated by the Houser angular index (τ4). In [CdLBr(μ-Br)]2 (1), each cadmium center is five-coordinated by two iminic nitrogen atoms from Schiff base ligand, two μ2-bridging bromide anions and one terminal coordinating bromide anion. The metal center in this centrosymmetric dimer has a distorted square-pyramidal geometry. [Hg2L(μ-I)2I2] (2) consists of two four-coordinated mercury centers with different coordination spheres (HgN2I2 for Hg1 and HgI4 for Hg2). The TG/DTG diagrams showed that both complexes were completely decomposed under a nitrogen atmosphere. Furthermore, antibacterial activities of compounds have been screened against various bacteria and fungi by Disk diffusion method. Mercury complex inhibited the growth of the microorganisms more efficient than cadmium complex. DNA cleavage potential of compounds was evaluated by agarose gel electrophoresis method. Finally, nano-structure cadmium complex was sono-chemically synthesized and applied as precursor for preparation of cadmium oxide nanoparticles.

  20. Synthesis, crystal growth, thermal studies and scaled quantum chemical studies of structural and vibrational spectra of the highly efficient organic NLO crystal: 1-(4-Aminophenyl)-3-(3,4-dimethoxyphenyl)-prop-2-en-1-one

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Lynnette [Department of Physics, Bishop Moore College, Mavelikara, Alappuzha 690110, Kerala (India); Department of Physics, C.M.S College, Kottayam 686001, Kerala (India); Sajan, D., E-mail: dsajand@gmail.com [Department of Physics, Bishop Moore College, Mavelikara, Alappuzha 690110, Kerala (India); Shettigar, Venkataraya [Department of Physics, Gokhale Centenary College, Ankola 581 314, Karnataka (India); Chaitanya, K. [Key Laboratory of Soft Chemistry and Functional Materials of MOE, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Misra, Neeraj [Department of Physics, University of Lucknow, Lucknow 22607 (India); Sundius, Tom [Department of Physics, University of Helsinki, P.O. Box 64, FIN-00014 Helsinki (Finland); Němec, I. [Charles University in Prague, Faculty of Science, Department of Inorganic Chemistry, Hlavova 8, 128 40 Prague 2 (Czech Republic)

    2013-08-15

    A new chalcone derivative, 1-(4-aminophenyl)-3-(3,4-dimethoxyphenyl)-prop-2-en-1-one (DMAC) was synthesized and single crystals were grown by slow evaporation technique. The FT-Raman and FT-IR spectra of the sample were recorded in the region 3700–100 cm{sup −1} and 4000–400 cm{sup −1}, respectively. The spectra were interpreted with the aid of normal coordinate analysis following structure optimizations and force field calculations based on density functional theory (DFT) at the B3LYP/6-311+G(d,p) level of theory. Normal coordinate calculations were performed using the DFT force field, corrected by a recommended set of scaling factors, yielding fairly good agreement between the observed and calculated wavenumbers. DMAC is thermally stable up to 220.0 °C and optically transparent in the visible region. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping electron density isosurface with electrostatic potential surfaces (ESP). The SHG efficiency of DMAC is observed to be 10 times that of standard urea crystal of identical particle size. - Highlights: • A chalcone derivative, DMAC has been synthesized and crystals are grown. • FT-IR and FT-Raman spectra, thermogravimetric and UV–Vis studies were carried out. • SHG effect from a centrosymmetric crystal has been reported.

  1. Studies on the growth aspects, structural, thermal, dielectric and third order nonlinear optical properties of solution grown 4-methylpyridinium p-nitrophenolate single crystal

    Science.gov (United States)

    Devi, S. Reena; Kalaiyarasi, S.; Zahid, I. MD.; Kumar, R. Mohan

    2016-11-01

    An ionic organic optical crystal of 4-methylpyridinium p-nitrophenolate was grown from methanol by slow evaporation method at ambient temperature. Powder and single crystal X-ray diffraction studies revealed the crystal system and its crystalline perfection. The rocking curve recorded from HRXRD study confirmed the crystal quality. FTIR spectral analysis confirmed the functional groups present in the title compound. UV-visible spectral study revealed the optical window and band gap of grown crystal. The thermal, electrical and surface laser damage threshold properties of harvested crystal were examined by using TGA/DTA, LCR/Impedance Analyzer and Nd:YAG laser system respectively. The third order nonlinear optical property of grown crystal was elucidated by Z-scan technique.

  2. Effect of second ligand on the luminescence of Samarium (III) dibenzoylmethane complexes: Syntheses, crystal structures, thermal analysis and luminescence study

    Indian Academy of Sciences (India)

    Muhammad Idiris Saleh; Min Yee Choo; Tai Wei Chan; Mohd R Razali

    2015-12-01

    The ternary complexes of Sm(III) with dibenzoylmethane (dbm) were synthesized by introducing 1,10-phenanthroline (phen), 4,7-dimethyl-1,10-phenanthroline (dmphen), 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen), 4,7-diphenyl-1,10-phenanthroline (dpphen), 2,2-bipyridyl (bpy), 4,4’-dimethyl-2,2-bipyridyl (4,4-dmbpy), 5,5’-dimethyl-2,2-bipyridyl (5,5-dmbpy) and 4,4’-di-tert-butyl-2,2-bipyridyl (4,4-dtbbpy) as a second ligand. The complexes were isolated and characterized by elemental analysis (CHN), thermogravimetric analysis (TGA), IR spectroscopy, luminescence spectroscopy and single crystal X-ray diffraction. Structural study shows that in all complexes Sm(III) is in square antiprism geometry. All complexes emit strong luminescence under ultraviolet excitation. The strongest emission is at 643 nm which can be assigned for 4G5/2 to 6H9/2 transition, equivalent to energy of 15550 cm−1. The addition of the second ligand has increased the emission intensity of the complexes while the transition is maintained.

  3. Frustrated polymer crystal structures

    Science.gov (United States)

    Lotz, B.; Strasbourg, 67083

    1997-03-01

    Several crystal structures or polymorphs of chiral or achiral polymers and biopolymers with three fold conformation of the helix have been found to conform to a common and -with one exception(Puterman, M. et al, J. Pol. Sci., Pol. Phys. Ed., 15, 805 (1977))- hitherto unsuspected packing scheme. The trigonal unit-cell contains three isochiral helices; the azimuthal setting of one helix differs significantly from that of the other two, leading to a so-called frustrated packing scheme, in which the environment of conformationally identical helices differs. Two variants of the frustrated scheme are analyzed. Similarities with frustrated two dimensional magnetic systems are underlined. Various examples of frustration in polymer crystallography are illustrated via the elucidation or reinterpretation of crystal phases or polymorphs of polyolefins, polyesters, cellulose derivatives and polypeptides. Structural manifestations (including AFM evidence) and morphological consequences of frustration are presented, which help diagnose the existence of this original packing of polymers.(Work done with L. Cartier, D. Dorset, S. Kopp, T. Okihara, M. Schumacher, W. Stocker.)

  4. Solid state parameters, structure elucidation, High Resolution X-Ray Diffraction (HRXRD), phase matching, thermal and impedance analysis on L-Proline trichloroacetate (L-PTCA) NLO single crystals.

    Science.gov (United States)

    Kalaiselvi, P; Raj, S Alfred Cecil; Jagannathan, K; Vijayan, N; Bhagavannarayana, G; Kalainathan, S

    2014-11-11

    Nonlinear optical single crystal of L-Proline trichloroacetate (L-PTCA) was successfully grown by Slow Evaporation Solution Technique (SEST). The grown crystals were subjected to single crystal X-ray diffraction analysis to confirm the structure. From the single crystal XRD data, solid state parameters were determined for the grown crystal. The crystalline perfection has been evaluated using high resolution X-ray diffractometer. The frequencies of various functional groups were identified from FTIR spectral analysis. The percentage of transmittance was obtained from UV Visible spectral analysis. TGA-DSC measurements indicate the thermal stability of the crystal. The dielectric constant, dielectric loss and ac conductivity were measured by the impedance analyzer. The DC conductivity was calculated by the cole-cole plot method.

  5. Synthesis, Crystal Structure and Kinetic Mechanism of Thermal Decomposition of a Zinc(II) Complex with N-Salicylidene-p-toluidine

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guo-Liang; WEN Yi-Hang; YU Yu-Ye

    2006-01-01

    The title complex, Zn(C14H13NO)2Cl2 1, has been synthesized by the reaction of zinc chloride with Schiff base ligand N-salicylidene-p-toluidine and its structure was determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group Cc with a = 14.896(3), b = 12.506(2), c = 15.352(3)(A), β = 114.711(4)o, V = 2598.0(8) (A)3, C28H26ZnCl2N2O2, Mr = 558.80, Z = 4, Dc = 1.429 g/cm3, μ = 1.179 mm-1, Flack parameter = 0.027(19), F(000) = 1152, R = 0.0709 and wR = 0.1041 for 3117 observed reflections (I > 2σ(I)). In complex 1, the center Zn ion is four-coordinated by two O atoms from two Schiff base ligands and two Cl atoms in a distorted tetrahedral geometry. Additionally, the thermal decomposition of complex 1 as well as its kinetic mechanisms and equations is studied under the non-isothermal integral and differential methods in air by TG-DTG curves.

  6. Inorganic Crystal Structure Database (ICSD)

    Science.gov (United States)

    SRD 84 FIZ/NIST Inorganic Crystal Structure Database (ICSD) (PC database for purchase)   The Inorganic Crystal Structure Database (ICSD) is produced cooperatively by the Fachinformationszentrum Karlsruhe(FIZ) and the National Institute of Standards and Technology (NIST). The ICSD is a comprehensive collection of crystal structure data of inorganic compounds containing more than 140,000 entries and covering the literature from 1915 to the present.

  7. Crystal structure of ruthenocenecarbonitrile

    Directory of Open Access Journals (Sweden)

    Frank Strehler

    2015-04-01

    Full Text Available The molecular structure of ruthenocenecarbonitrile, [Ru(η5-C5H4C[triple-bond]N(η5-C5H5], exhibits point group symmetry m, with the mirror plane bisecting the molecule through the C[triple-bond]N substituent. The RuII atom is slightly shifted from the η5-C5H4 centroid towards the C[triple-bond]N substituent. In the crystal, molecules are arranged in columns parallel to [100]. One-dimensional intermolecular π–π interactions [3.363 (3 Å] between the C[triple-bond]N carbon atom and one carbon of the cyclopentadienyl ring of the overlaying molecule are present.

  8. Crystal structure of propaquizafop

    Directory of Open Access Journals (Sweden)

    Youngeun Jeon

    2014-12-01

    Full Text Available The title compound, C22H22ClN3O5 {systematic name: 2-(propan-2-ylideneaminooxyethyl (R-2-[4-(6-chloroquinoxalin-2-yloxyphenoxy]propionate}, is a herbicide. The asymmetric unit comprises two independent molecules in which the dihedral angles between the phenyl ring and the quinoxaline ring plane are 75.93 (7 and 82.77 (8°. The crystal structure features C—H...O, C—H...N, and C—H...Cl hydrogen bonds, as well as weak π–π interactions [ring-centroid separation = 3.782 (2 and 3.5952 (19 Å], resulting in a three-dimensional architecture.

  9. 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.

  10. Influence of bis-thiourea nickel nitrate on the structural, optical, electrical, thermal and mechanical behavior of a KDP single crystal for NLO applications

    Science.gov (United States)

    Rasal, Y. B.; Shaikh, R. N.; Shirsat, M. D.; Kalainathan, S.; Hussaini, S. S.

    2017-03-01

    A single crystal of bis-thiourea nickel nitrate (BTNN) doped potassium dihydrogen phosphate (KDP) has been grown from solution at room temperature by a slow evaporation technique. The cell parameters of the grown crystals were determined using single crystal x-ray diffraction analysis. The different functional groups of the grown crystal were confirmed using Fourier transform infrared analysis. The improved optical parameters of the grown crystal have been evaluated in the range of 200-900 nm using UV-visible spectral analysis. The grown crystal was transparent in the entire visible region and the band gap value was found to be 4.96 eV. The influence of BTNN on the third order nonlinear optical properties of KDP crystal has been investigated by means of the Z-scan technique. The second harmonic generation (SHG) efficiency of grown crystal measured using a Nd-YAG laser is 1.98 times higher than that of pure KDP. The third order nonlinear optical susceptibility (χ 3) and nonlinear absorption coefficient (β) of BTNN doped KDP crystal is found to be 1.77  ×  10-5 esu and 5.57  ×  10-6 cm W-1 respectively. The laser damage threshold (LDT) energy for the grown crystal has been measured by using a Q-switched Nd:YAG laser source. The bis-thiourea nickel nitrate shows authoritative impact on the dielectric properties of doped crystal. The influence of bis-thiourea nickel nitrate on the mechanical behavior of KDP crystal has been investigated using Vickers microhardness intender. The thermal behavior of BTNN doped KDP crystal has been analyzed by TGA/DTA analysis.

  11. Studies on synthesis, structural, luminescent and thermal properties of a new non-linear optical crystal: 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6-trinitrophenolate

    Science.gov (United States)

    Dhamodharan, P.; Sathya, K.; Dhandapani, M.

    2017-03-01

    A new organic proton transfer complex having NLO activity, 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6-trinitrophenolate (ATHTP), was crystallized to investigate the factors which stabilize the structure of the crystal. The compound crystallizes in triclinic system with space group P-1. Elemental analysis, thermal analysis, UV-Vis-NIR, FT-IR and NMR spectral analyses were carried out to characterize the crystal. Optical, spectral and thermal properties of the title crystal were analyzed to recommend the material for optical applications. Z-scan was used to measure the effective third-order nonlinear optical susceptibility and nonlinear refractive index. The crystal structure was determined using single crystal XRD method and the structure was optimized using Gaussian 09 program at B3LYP/6-311++G(d,p) level of basis set. This hydrogen bond interactions led to the increase in first-order hyperpolarizability of ATHTP and was 30 times greater than that of urea. Hirshfeld analyses surface analysis was carried out to explore intermolecular interactions in the crystalline state.

  12. Synthesis, crystal structure, thermal and theoretical studies of bis(N-ethyl-N-phenyldithiocarbamato) Ni(II) and (N-ethyl-N-phenyldithiocarbamato) (isothiocyanato) (triphenylphosphine) Ni(II)

    Indian Academy of Sciences (India)

    DAMIAN C ONWUDIWE; MWADHAM M KABANDA; ENO E EBENSO; ERIC HOSTEN

    2016-07-01

    Homoleptic and heteroleptic Ni(II) complexes represented as NiL¹₂ and NiL¹L²L³ (where, L¹ = N-ethyl-N-phenyldithiocarbamato anion, L² = isothiocyanato anion, and L³ = triphenylphosphine) were synthesized. The complexes have been characterized by elemental, IR, NMR, and single-crystal X-ray analysis. The thermal decomposition behaviour of the complexes were studied using thermogravimetric analysis (TGA). The optimized geometry and the electronic analysis of the type of bonding within the complex structures were performed using methods based on the density functional theory and atom in molecule (AIM) analysis method. X-ray structural analysis of both complexes confirms distorted square planar geometry about the Ni atom. The TGA indicates that the complexes belong to the class of volatile dithiocarbamates which yield the corresponding metal sulphide without any intermediate products. Structural parameters from crystallographic and DFT studies have been compared and found to correlate with each other. The small discrepancies in geometric parameters are attributable to H-bonding and packing interactions within the lattice which are not modelled during computational study. AIM analysis suggests that in NiL¹L²L³ , the Ni· · · L interactions are more covalent in nature whereas in NiL¹₂ complex, they are more ionic in character.

  13. Thermal behaviour of strontium tartrate single crystals grown in gel

    Indian Academy of Sciences (India)

    M H Rahimkutty; K Rajendra Babu; K Sreedharan Pillai; M R Sudarsana Kumar; C M K Nair

    2001-04-01

    Thermal behaviour of strontium tartrate crystals grown with the aid of sodium metasilicate gel is investigated using thermogravimetry (TG) and differential thermal analysis (DTA). Effect of magnetic field and dopant (Pb)2+ on the crystal stability is also studied using thermal analysis. This study reveals that water molecules are locked up in the lattice with different strengths in the grown crystals.

  14. Crystal Structure and Thermal Expansion Properties of Lu_(2-x)Fe_xMo_3O_(12)

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Low or zero thermal expansion materials have a lot of potential applications in space shuttle, microelectronic components, and optical mirrors et al. Polycrystalline samples Lu2-xFexMo3O12 have been prepared successfully by solid state reaction,

  15. Photonic Crystal Laser Accelerator Structures

    Energy Technology Data Exchange (ETDEWEB)

    Cowan, Benjamin M

    2003-05-21

    Photonic crystals have great potential for use as laser-driven accelerator structures. A photonic crystal is a dielectric structure arranged in a periodic geometry. Like a crystalline solid with its electronic band structure, the modes of a photonic crystal lie in a set of allowed photonic bands. Similarly, it is possible for a photonic crystal to exhibit one or more photonic band gaps, with frequencies in the gap unable to propagate in the crystal. Thus photonic crystals can confine an optical mode in an all-dielectric structure, eliminating the need for metals and their characteristic losses at optical frequencies. We discuss several geometries of photonic crystal accelerator structures. Photonic crystal fibers (PCFs) are optical fibers which can confine a speed-of-light optical mode in vacuum. Planar structures, both two- and three-dimensional, can also confine such a mode, and have the additional advantage that they can be manufactured using common microfabrication techniques such as those used for integrated circuits. This allows for a variety of possible materials, so that dielectrics with desirable optical and radiation-hardness properties can be chosen. We discuss examples of simulated photonic crystal structures to demonstrate the scaling laws and trade-offs involved, and touch on potential fabrication processes.

  16. Thermally stable deployable structure

    Science.gov (United States)

    Kegg, Colleen M.

    1988-01-01

    A deployable structure which meets stringent thermal and strength requirements in a space environment was developed. A mast with a very low coefficient of thermal expansion (CTE) was required to limit the movement from thermal distortion over the temperature range of -200 C to 80 C to .064 cm (.025 in). In addition, a high bending strength over the temperature range and weight less than 18.1 kg (40 lbs) was needed. To meet all of the requirements, a composite, near-zero CTE structure was developed. The measured average CTE over the temperature range for the mast was .70 x .000001/C (.38 x .000001/F). The design also has the advantage of being adjustable to attain other specific CTE if desired.

  17. Crystal structure of fipronil

    Directory of Open Access Journals (Sweden)

    Hyunjin Park

    2017-10-01

    Full Text Available The title compound, C12H4Cl2F6N4OS {systematic name: 5-amino-1-[2,6-dichloro-4-(trifluoromethylphenyl]-4-[(trifluoromethanesulfinyl]-1H-pyrazole-3-carbonitrile}, is a member of the phenylpyrazole group of acaricides, and one of the phenylpyrazole group of insecticides. The dihedral angle between the planes of the pyrazole and benzene rings is 89.03 (9°. The fluorine atoms of the trifluoromethyl substituent on the benzene ring are disordered over two sets of sites, with occupancy ratios 0.620 (15:0.380 (15. In the crystal, C—N...π interactions [N...ring centroid = 3.607 (4 Å] together with N—H...N and C—H...F hydrogen bonds form a looped chain structure along [10\\overline{1}]. Finally, N—H...O hydrogen bonds and C—Cl...π interactions [Cl...ring centroid = 3.5159 (16 Å] generate a three-dimensional structure. Additionally, there are a short intermolecular F... F contacts present.

  18. Studies on synthesis, structural, luminescent and thermal properties of a new non-linear optical crystal: 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6-trinitrophenolate

    Energy Technology Data Exchange (ETDEWEB)

    Dhamodharan, P.; Sathya, K.; Dhandapani, M., E-mail: chemistrydhandapani@gmail.com

    2017-03-01

    A new organic proton transfer complex having NLO activity, 4-amino-4H-1,2,4-triazol-1-ium-3-hydroxy-2,4,6-trinitrophenolate (ATHTP), was crystallized to investigate the factors which stabilize the structure of the crystal. The compound crystallizes in triclinic system with space group P-1. Elemental analysis, thermal analysis, UV–Vis–NIR, FT-IR and NMR spectral analyses were carried out to characterize the crystal. Optical, spectral and thermal properties of the title crystal were analyzed to recommend the material for optical applications. Z-scan was used to measure the effective third-order nonlinear optical susceptibility and nonlinear refractive index. The crystal structure was determined using single crystal XRD method and the structure was optimized using Gaussian 09 program at B3LYP/6-311++G(d,p) level of basis set. This hydrogen bond interactions led to the increase in first-order hyperpolarizability of ATHTP and was 30 times greater than that of urea. Hirshfeld analyses surface analysis was carried out to explore intermolecular interactions in the crystalline state. - Highlights: • Single crystals were grown by slow evaporation solution growth technique. • N-H…O, O-H…O and C-H…O type of interactions lead to stable network. • The thermal stability of the compound was investigated by TG/DTA analyses. • The third-order nonlinear optical susceptibility is found to be 2.1×10{sup −7} esu. • Hirshfeld analyses explore covalent and non covalent interactions.

  19. Theoretical studies on the crystal structure, thermodynamic properties, detonation performance and thermal stability of cage-tetranitrotetraazabicyclooctane as a novel high energy density compound.

    Science.gov (United States)

    Zhao, Guo-zheng; Lu, Ming

    2013-01-01

    The B3LYP/6-31G (d) method of density functional theory (DFT) was used to study molecular geometry, electronic structure, infrared spectrum (IR) and thermodynamic properties. The heat of formation (HOF) and calculated density were estimated to evaluate the detonation properties using Kamlet-Jacobs equations. Thermal stability of 3,5,7,10,12,14,15,16-octanitro- 3,5,7,10,12,14,15,16-octaaza-heptacyclo[7.5.1.1(2,8).0(1,11).0(2,6).0(4,13).0(6,11)]hexadecane (cage-tetranitrotetraazabicyclooctane) was investigated by calculating the bond dissociation energy (BDE) at unrestricted B3LYP/6-31G (d) level. The calculated results show that the N-NO2 bond is a trigger bond during thermolysis initiation process. The crystal structure obtained by molecular mechanics (MM) methods belongs to Pna2(1) space group, with cell parameters a=12.840 Å, b=9.129 Å, c=14.346 Å, Z=6 and ρ=2.292 g·cm(-3). Both the detonation velocity of 9.96 km·s(-1) and the detonation pressure of 47.47 GPa are better than those of CL-20. According to the quantitative standard of energetics and stability, as a high energy density compound (HEDC), cage-tetranitrotetraazabicyclooctane essentially satisfies this requirement.

  20. Prediction of molecular crystal structures

    CERN Document Server

    Beyer, T

    2001-01-01

    The ab initio prediction of molecular crystal structures is a scientific challenge. Reliability of first-principle prediction calculations would show a fundamental understanding of crystallisation. Crystal structure prediction is also of considerable practical importance as different crystalline arrangements of the same molecule in the solid state (polymorphs)are likely to have different physical properties. A method of crystal structure prediction based on lattice energy minimisation has been developed in this work. The choice of the intermolecular potential and of the molecular model is crucial for the results of such studies and both of these criteria have been investigated. An empirical atom-atom repulsion-dispersion potential for carboxylic acids has been derived and applied in a crystal structure prediction study of formic, benzoic and the polymorphic system of tetrolic acid. As many experimental crystal structure determinations at different temperatures are available for the polymorphic system of parac...

  1. THE CRYSTAL STRUCTURE OF DIPHENYLTELLURIUM DIBROMIDE,

    Science.gov (United States)

    TELLURIUM COMPOUNDS, *ORGANOMETALLIC COMPOUNDS, CRYSTAL STRUCTURE , CRYSTAL STRUCTURE , BROMIDES, SYMMETRY(CRYSTALLOGRAPHY), X RAY DIFFRACTION, FOURIER ANALYSIS, LEAST SQUARES METHOD, MOLECULAR STRUCTURE, CHEMICAL BONDS.

  2. REFINEMENT OF THE CRYSTAL STRUCTURE OF GUANIDINIUM ALUMINUM SULFATE HEXAHYDRATE.

    Science.gov (United States)

    FERROELECTRIC CRYSTALS, * CRYSTAL STRUCTURE ), (*GUANIDINES, CRYSTAL STRUCTURE ), (*ALUMINUM COMPOUNDS, CRYSTAL STRUCTURE ), SULFATES, HYDRATES, X RAY DIFFRACTION, CHROMIUM COMPOUNDS, CRYSTAL LATTICES, CHEMICAL BONDS

  3. Demonstration of Crystal Structure.

    Science.gov (United States)

    Neville, Joseph P.

    1985-01-01

    Describes an experiment where equal parts of copper and aluminum are heated then cooled to show extremely large crystals. Suggestions are given for changing the orientation of crystals by varying cooling rates. Students are more receptive to concepts of microstructure after seeing this experiment. (DH)

  4. Post-Synthetic Shaping of Porosity and Crystal Structure of Ln-Bipy-MOFs by Thermal Treatment

    Directory of Open Access Journals (Sweden)

    Philipp R. Matthes

    2015-07-01

    Full Text Available The reaction of anhydrous lanthanide chlorides together with 4,4′-bipyridine yields the MOFs 2∞[Ln2Cl6(bipy3]·2bipy, with Ln = Pr − Yb, bipy = 4,4′-bipyridine, and 3∞[La2Cl6(bipy5]·4bipy. Post-synthetic thermal treatment in combination with different vacuum conditions was successfully used to shape the porosity of the MOFs. In addition to the MOFs microporosity, a tuneable mesoporosity can be implemented depending on the treatment conditions as a surface morphological modification. Furthermore, thermal treatment without vacuum results in several identifiable crystalline high-temperature phases. Instead of collapse of the frameworks upon heating, further aggregation under release of bipy is observed. 3∞[LaCl3(bipy] and 2∞[Ln3Cl9(bipy3], with Ln = La, Pr, Sm, and 1∞[Ho2Cl6(bipy2] were identified and characterized, which can also exhibit luminescence. Besides being released upon heating, the linker 4,4′-bipyridine can undergo activation of C-C bonding in ortho-position leading to the in-situ formation of 4,4′:2′,2′′:4′′,4′′′-quaterpyridine (qtpy. qtpy can thereby function as linker itself, as shown for the formation of the network 2∞[Gd2Cl6(qtpy2(bipy2]·bipy. Altogether, the manuscript elaborates the influence of thermal treatment beyond the usual activation procedures reported for MOFs.

  5. Crystal structure of oxamyl

    Directory of Open Access Journals (Sweden)

    Eunjin Kwon

    2016-12-01

    Full Text Available The title compound, C7H13N3O3S [systematic name: (Z-methyl 2-dimethylamino-N-(methylcarbamoyloxy-2-oxoethanimidothioate], is an oxime carbamate acaride, insecticide and nematicide. The asymmetric unit comprises two independent molecules, A and B. The dihedral angles between the mean planes [r.m.s. deviations = 0.0017 (A and 0.0016 Å (B] of the acetamide and oxyimino groups are 88.80 (8° for A and 87.05 (8° for B. In the crystal, N/C—H...O hydrogen bonds link adjacent molecules, forming chains along the a axis. The chains are further linked by C—H...O hydrogen bonds, resulting in a three-dimensional network with alternating rows of A and B molecules in the bc plane stacked along the a-axis direction. The structure was refined as an inversion twin with a final BASF parameter of 0.16 (9.

  6. Coherent thermal conductance of 1-D photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Tschikin, Maria [Institut für Physik, Carl von Ossietzky Universität, D-26111 Oldenburg (Germany); Ben-Abdallah, Philippe [Laboratoire Charles Fabry, UMR 8501, Institut d' Optique, CNRS, Université Paris-Sud, 2, Avenue Augustin Fresnel, RD128, 91127 Palaiseau Cedex (France); Biehs, Svend-Age, E-mail: biehs@theorie.physik.uni-oldenburg.de [Institut für Physik, Carl von Ossietzky Universität, D-26111 Oldenburg (Germany)

    2012-10-01

    We present an exact calculation of coherent thermal conductance in 1-D multilayer photonic crystals using the S-matrix method. In particular, we study the thermal conductance in a bilayer structure of Si/vacuum or Al{sub 2}O{sub 3}/vacuum slabs by means of the exact radiative heat flux expression. Based on the results obtained for the Al{sub 2}O{sub 3}/vacuum structure we show by comparison with previous works that the material losses and (localized) surface modes supported by the inner layers play a fundamental role and cannot be omitted in the definition of thermal conductance. Our results could have significant implications in the conception of efficient thermal barriers.

  7. High-efficiency photonic crystal narrowband thermal emitters

    Science.gov (United States)

    Farfan, G. B.; Su, M. F.; Reda Taha, M. M.; El-Kady, I.

    2010-02-01

    Photonic crystals (PhC) are artificial structures fabricated with a periodicity in the dielectric function. This periodic electromagnetic potential results in creation of energy bandgaps where photon propagation is prohibited. PhC structures have promising use in thermal applications if optimized to operate at specific thermal emission spectrum. Here, novel utilization of optimized PhC's in thermal applications is presented. We demonstrate through numerical simulation the modification of the thermal emission spectrum by a metallic photonic crystal (PhC) to create high-efficiency multispectral thermal emitters. These emitters funnel radiation from a broad emission spectrum associated with a Plancklike distribution into a prescribed narrow emission band. A detailed quantitative evaluation of the spectral and power efficiencies of a PhC thermal emitter and its portability across infrared (IR) spectral bands are provided. We show an optimized tungsten PhC with a predominant narrow-band emission profile with an emitter efficiency that is more than double that of an ideal blackbody and ~65-75% more power-efficiency across the IR spectrum. We also report on using optimal three-dimensional Lincoln log photonic crystal (LL-PhC) emitters for thermophotovoltaic (TPV) generation as opposed to using a passive filtering approach to truncate the broadband thermal source emission to match the bandgap of a photovoltaic (PV) cell. The emitter performance is optimized for the 1-2μm PV band using different PhC materials, specifically copper, silver and gold. The use of the proposed PhC in TPV devices can produce significant energy savings not reported before. The optimal design of the PhC geometry is obtained by implementing a variety of optimization methods integrated with artificial intelligence (AI) algorithms.

  8. Structural, thermal, laser damage, photoconductivity, NLO and mechanical properties of modified vertical Bridgman method grown AgGa0.5In0.5Se2 single crystal

    Science.gov (United States)

    Vijayakumar, P.; Ramasamy, P.

    2016-08-01

    AgGa0.5In0.5Se2 single crystal was grown using modified vertical Bridgman method. The structural perfection of the AgGa0.5In0.5Se2 single crystal has been analyzed by high-resolution X-ray diffraction rocking curve measurements. The structural and compositional uniformities of AgGa0.5In0.5Se2 were studied using Raman scattering spectroscopy at room temperature. The FWHM of the Γ1 (W1) and Γ5L (Γ15) measured at different regions of the crystal confirms that the composition throughout its length is fairly uniform. Thermal properties of the as-grown crystal, including specific heat, thermal diffusivity and thermal conductivity have been investigated. The multiple shot surface laser damage threshold value was measured using Nd:YAG laser. Photoconductivity measurements with different temperatures have confirmed the positive photoconducting behavior. Second harmonic generation (SHG) on powder samples has been measured using the Kurtz and Perry technique and the results display that AgGa0.5In0.5Se2 is a phase-matchable NLO material. The hardness behavior has been measured using Vickers micro hardness measurement and the indentation size effect has been observed. The classical Meyer's law, propositional resistance model and modified propositional resistance model have been used to analyse the micro hardness behavior.

  9. Syntheses, Crystal Structures, Magnetic Behaviours, and Thermal Properties of Three Hydrogen-Bonding Networks Containing Dicyanamide and 4-Hydroxypyridine

    Directory of Open Access Journals (Sweden)

    Lingling Zheng

    2013-01-01

    Full Text Available Three new dicyanamide-bridged polymeric complexes of {[Mn(dca2(L2]·2H2O}n (1, {[Cd(dca2(L2]·2H2O}n (2, and {[Co(dca2(L2]2(L}n (3 (dca = dicyanamide, L = pyridinium-4-olate have been synthesized and structurally characterized. In the three compounds, the protons of hydroxyl groups of 4-hydroxypyridine transfer to pyridyl nitrogen atoms. Compounds 1 and 2 are isomorphous forming one-dimensional [M(dca2(L2]n chains where metals are connected by double dca anions. These one-dimensional chains are extended into two-dimensional layers through weak C–H⋯N hydrogen bonds. Further, these layers are assembled into a three-dimensional supramolecular network through N–H⋯O, O–H⋯O hydrogen bonds. Complex 3 is a coordination layer of (4, 4 topology with octahedral metal centers linked by four single μ1,5-bridges. These layers are interlocked by N–H⋯O, O–H⋯O hydrogen bonds from coordinated water molecules and free L molecules, which leads to a three-dimensional supramolecular architecture. The variable temperature magnetic susceptibilities measurement of compounds 1 and 3 shows the existence of weak antiferromagnetic interactions between the metal centers. The thermogravimetric analyses of the compounds 1–3 are also discussed.

  10. Prediction of molecular crystal structures

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, Theresa

    2001-07-01

    The ab initio prediction of molecular crystal structures is a scientific challenge. Reliability of first-principle prediction calculations would show a fundamental understanding of crystallisation. Crystal structure prediction is also of considerable practical importance as different crystalline arrangements of the same molecule in the solid state (polymorphs)are likely to have different physical properties. A method of crystal structure prediction based on lattice energy minimisation has been developed in this work. The choice of the intermolecular potential and of the molecular model is crucial for the results of such studies and both of these criteria have been investigated. An empirical atom-atom repulsion-dispersion potential for carboxylic acids has been derived and applied in a crystal structure prediction study of formic, benzoic and the polymorphic system of tetrolic acid. As many experimental crystal structure determinations at different temperatures are available for the polymorphic system of paracetamol (acetaminophen), the influence of the variations of the molecular model on the crystal structure lattice energy minima, has also been studied. The general problem of prediction methods based on the assumption that the experimental thermodynamically stable polymorph corresponds to the global lattice energy minimum, is that more hypothetical low lattice energy structures are found within a few kJ mol{sup -1} of the global minimum than are likely to be experimentally observed polymorphs. This is illustrated by the results for molecule I, 3-oxabicyclo(3.2.0)hepta-1,4-diene, studied for the first international blindtest for small organic crystal structures organised by the Cambridge Crystallographic Data Centre (CCDC) in May 1999. To reduce the number of predicted polymorphs, additional factors to thermodynamic criteria have to be considered. Therefore the elastic constants and vapour growth morphologies have been calculated for the lowest lattice energy

  11. Thermal conductivity measurements of laser crystals by infrared thermography. Application to Nd:doped crystals

    OpenAIRE

    Didierjean, Julien; Hérault, Emilie; Balembois, François; Georges, Patrick

    2008-01-01

    International audience; We present a thermal conductivity measurement method for laser crystals based on thermal mapping of the crystal face by an infrared camera. Those measurements are performed under end-pumping of the laser crystal and during laser operation. The calculation of the fraction of pump power converted into heat is therefore simplified, and it is possible to link easily the temperature in the crystal to the thermal conductivity. We demonstrate the efficiency of this measuremen...

  12. Thermal characterization of nanoscale phononic crystals using supercell lattice dynamics

    Science.gov (United States)

    Davis, Bruce L.; Hussein, Mahmoud I.

    2011-12-01

    The concept of a phononic crystal can in principle be realized at the nanoscale whenever the conditions for coherent phonon transport exist. Under such conditions, the dispersion characteristics of both the constitutive material lattice (defined by a primitive cell) and the phononic crystal lattice (defined by a supercell) contribute to the value of the thermal conductivity. It is therefore necessary in this emerging class of phononic materials to treat the lattice dynamics at both periodicity levels. Here we demonstrate the utility of using supercell lattice dynamics to investigate the thermal transport behavior of three-dimensional nanoscale phononic crystals formed from silicon and cubic voids of vacuum. The periodicity of the voids follows a simple cubic arrangement with a lattice constant that is around an order of magnitude larger than that of the bulk crystalline silicon primitive cell. We consider an atomic-scale supercell which incorporates all the details of the silicon atomic locations and the void geometry. For this supercell, we compute the phonon band structure and subsequently predict the thermal conductivity following the Callaway-Holland model. Our findings dictate that for an analysis based on supercell lattice dynamics to be representative of the properties of the underlying lattice model, a minimum supercell size is needed along with a minimum wave vector sampling resolution. Below these minimum values, a thermal conductivity prediction of a bulk material based on a supercell will not adequately recover the value obtained based on a primitive cell. Furthermore, our results show that for the relatively small voids and void spacings we consider (where boundary scattering is dominant), dispersion at the phononic crystal unit cell level plays a noticeable role in determining the thermal conductivity.

  13. Thermal characterization of nanoscale phononic crystals using supercell lattice dynamics

    Directory of Open Access Journals (Sweden)

    Bruce L. Davis

    2011-12-01

    Full Text Available The concept of a phononic crystal can in principle be realized at the nanoscale whenever the conditions for coherent phonon transport exist. Under such conditions, the dispersion characteristics of both the constitutive material lattice (defined by a primitive cell and the phononic crystal lattice (defined by a supercell contribute to the value of the thermal conductivity. It is therefore necessary in this emerging class of phononic materials to treat the lattice dynamics at both periodicity levels. Here we demonstrate the utility of using supercell lattice dynamics to investigate the thermal transport behavior of three-dimensional nanoscale phononic crystals formed from silicon and cubic voids of vacuum. The periodicity of the voids follows a simple cubic arrangement with a lattice constant that is around an order of magnitude larger than that of the bulk crystalline silicon primitive cell. We consider an atomic-scale supercell which incorporates all the details of the silicon atomic locations and the void geometry. For this supercell, we compute the phonon band structure and subsequently predict the thermal conductivity following the Callaway-Holland model. Our findings dictate that for an analysis based on supercell lattice dynamics to be representative of the properties of the underlying lattice model, a minimum supercell size is needed along with a minimum wave vector sampling resolution. Below these minimum values, a thermal conductivity prediction of a bulk material based on a supercell will not adequately recover the value obtained based on a primitive cell. Furthermore, our results show that for the relatively small voids and void spacings we consider (where boundary scattering is dominant, dispersion at the phononic crystal unit cell level plays a noticeable role in determining the thermal conductivity.

  14. Single-Crystal to Single-Crystal Reversible Transformations Induced by Thermal Dehydration in Keggin-Type Polyoxometalates Decorated with Copper(II-Picolinate Complexes: The Structure Directing Role of Guanidinium

    Directory of Open Access Journals (Sweden)

    Aroa Pache

    2015-05-01

    Full Text Available Three new hybrid inorganic-metalorganic compounds containing Keggin-type polyoxometalates, neutral copper(II-picolinate complexes and guanidinium cations have been synthesized in bench conditions and characterized by elemental analysis, infrared spectroscopy and single-crystal X-ray diffraction: the isostructural [C(NH23]4[{XW12O40}{Cu2(pic4}]·[Cu2(pic4(H2O]2·6H2O [X = Si (1, Ge (3] and [C(NH23]8[{SiW12O40}2{Cu(pic2}3{Cu2(pic4(H2O}2]·8H2O (2. The three compounds show a pronounced two-dimensional character owing to the structure-directing role of guanidinium. In 1 and 3, layers of [{XW12O40}{Cu2(pic4}]n4n− hybrid POM chains and layers of [Cu2(pic4(H2O] complexes and [C(NH23]+ cations pack alternately along the z axis. The hydrogen-bonding network established by guanidinium leads to a trihexagonal tiling arrangement of all copper(II-picolinate species. In contrast, layers of [C(NH23]+-linked [{SiW12O40}2{Cu(pic2}3]n8n− double chains where each Keggin cluster displays a {Cu2(pic4(H2O} moiety pointing at the intralamellar space are observed in 2. The thermal stability of 1–3 has been studied by thermogravimetric analyses and variable temperature powder X-ray diffraction. Compounds 1 and 3 undergo single-crystal to single-crystal transformations promoted by reversible dehydration processes and the structures of the corresponding anhydrous phases 1a and 3a have been established. Despite the fact that the [Cu2(pic4(H2O] dimeric complexes split into [Cu(pic2] monomers upon dehydration, the packing remains almost unaltered thanks to the preservation of the hydrogen-bonding network established by guanidinium and its associated Kagome-type lattice. Splitting of the dimeric complexes has been correlated with the electron paramagnetic resonance spectra.

  15. Thermally actuated resonant silicon crystal nanobalances

    Science.gov (United States)

    Hajjam, Arash

    As the potential emerging technology for next generation integrated resonant sensors and frequency references as well as electronic filters, micro-electro-mechanical resonators have attracted a lot of attention over the past decade. As a result, a wide variety of high frequency micro/nanoscale electromechanical resonators have recently been presented. MEMS resonators, as low-cost highly integrated and ultra-sensitive mass sensors, can potentially provide new opportunities and unprecedented capabilities in the area of mass sensing. Such devices can provide orders of magnitude higher mass sensitivity and resolution compared to Film Bulk Acoustic resonators (FBAR) or the conventional quartz and Surface Acoustic Wave (SAW) resonators due to their much smaller sizes and can be batch-fabricated and utilized in highly integrated large arrays at a very low cost. In this research, comprehensive experimental studies on the performance and durability of thermally actuated micromechanical resonant sensors with frequencies up to tens of MHz have been performed. The suitability and robustness of the devices have been demonstrated for mass sensing applications related to air-borne particles and organic gases. In addition, due to the internal thermo-electro-mechanical interactions, the active resonators can turn some of the consumed electronic power back into the mechanical structure and compensate for the mechanical losses. Therefore, such resonators can provide self-sustained-oscillation without the need for any electronic circuitry. This unique property has been deployed to demonstrate a prototype self-sustained sensor for air-borne particle monitoring. I have managed to overcome one of the obstacles for MEMS resonators, which is their relatively poor temperature stability. This is a major drawback when compared with the conventional quartz crystals. A significant decrease of the large negative TCF for the resonators has been attained by doping the devices with a high

  16. Crystal structure of cafenstrole

    Directory of Open Access Journals (Sweden)

    Gihaeng Kang

    2015-08-01

    Full Text Available The title compound (systematic name: N,N-diethyl-3-mesitylsulfonyl-1H-1,2,4-triazole-1-carboxamide, C16H22N4O3S, is a triazole herbicide. The dihedral angle between the planes of the triazole and benzene ring planes is 88.14 (10°. In the crystal, C—H...O hydrogen bonds and weak C—H...π interactions link adjacent molecules, forming one-dimensional chains along the a axis.

  17. Crystal structure of pseudoguainolide

    Directory of Open Access Journals (Sweden)

    Noureddine Beghidja

    2015-03-01

    Full Text Available The lactone ring in the title molecule, C15H22O3 (systematic name: 3,4a,8-trimethyldodecahydroazuleno[6,5-b]furan-2,5-dione, assumes an envelope conformation with the methine C atom adjacent to the the methine C atom carrying the methyl substituent being the flap atom. The other five-membered ring adopts a twisted conformation with the twist being about the methine–methylene C—C bond. The seven-membered ring is based on a twisted boat conformation. No specific interactions are noted in the the crystal packing.

  18. Thermal conductivity measurements of laser crystals by infrared thermography. Application to Nd:doped crystals.

    Science.gov (United States)

    Didierjean, Julien; Herault, Emilie; Balembois, François; Georges, Patrick

    2008-06-09

    We present a thermal conductivity measurement method for laser crystals based on thermal mapping of the crystal face by an infrared camera. Those measurements are performed under end-pumping of the laser crystal and during laser operation. The calculation of the fraction of pump power converted into heat is therefore simplified, and it is possible to link easily the temperature in the crystal to the thermal conductivity. We demonstrate the efficiency of this measurement method with a Nd:YAG crystal, before using it to compare Nd:YVO(4) and Nd:GdVO(4) crystals.

  19. Crystal structure of nuarimol

    Directory of Open Access Journals (Sweden)

    Gihaeng Kang

    2015-08-01

    Full Text Available The title compound [systematic name: (RS-(2-chlorophenyl(4-fluorophenyl(pyrimidin-5-ylmethanol], C17H12ClFN2O, is a pyrimidine fungicide. The asymmetric unit comprises two independent molecules, A and B, in which the dihedral angles between the plane of the pyrimidine ring and those of the chlorophenyl and fluorophenyl rings are 71.10 (6 and 70.04 (5° in molecule A, and 73.24 (5 and 89.30 (5° in molecule B. In the crystal, O—H...N hydrogen bonds link the components into [010] chains of alternating A and B molecules. The chains are cross-linked by C—H...F hydrogen bonds and weak C—H...π and C—Cl...π [Cl...ring centroid = 3.7630 (8 Å] interactions, generating a three-dimensional network.

  20. Thermal control structure and garment

    Energy Technology Data Exchange (ETDEWEB)

    Klett, James W [Knoxville, TN; Cameron, Christopher Stan [Sanford, NC

    2012-03-13

    A flexible thermally conductive structure. The structure generally includes a plurality of thermally conductive yarns, at least some of which are at least partially disposed adjacent to an elastomeric material. Typically, at least a portion of the plurality of thermally conductive yarns is configured as a sheet. The yarns may be constructed from graphite, metal, or similar materials. The elastomeric material may be formed from urethane or silicone foam that is at least partially collapsed, or from a similar material. A thermal management garment is provided, the garment incorporating a flexible thermally conductive structure.

  1. Crystal structure refinement with SHELXL.

    Science.gov (United States)

    Sheldrick, George M

    2015-01-01

    The improvements in the crystal structure refinement program SHELXL have been closely coupled with the development and increasing importance of the CIF (Crystallographic Information Framework) format for validating and archiving crystal structures. An important simplification is that now only one file in CIF format (for convenience, referred to simply as `a CIF') containing embedded reflection data and SHELXL instructions is needed for a complete structure archive; the program SHREDCIF can be used to extract the .hkl and .ins files required for further refinement with SHELXL. Recent developments in SHELXL facilitate refinement against neutron diffraction data, the treatment of H atoms, the determination of absolute structure, the input of partial structure factors and the refinement of twinned and disordered structures. SHELXL is available free to academics for the Windows, Linux and Mac OS X operating systems, and is particularly suitable for multiple-core processors.

  2. Crystal structure refinement with SHELXL

    Energy Technology Data Exchange (ETDEWEB)

    Sheldrick, George M., E-mail: gsheldr@shelx.uni-ac.gwdg.de [Department of Structural Chemistry, Georg-August Universität Göttingen, Tammannstraße 4, Göttingen 37077 (Germany)

    2015-01-01

    New features added to the refinement program SHELXL since 2008 are described and explained. The improvements in the crystal structure refinement program SHELXL have been closely coupled with the development and increasing importance of the CIF (Crystallographic Information Framework) format for validating and archiving crystal structures. An important simplification is that now only one file in CIF format (for convenience, referred to simply as ‘a CIF’) containing embedded reflection data and SHELXL instructions is needed for a complete structure archive; the program SHREDCIF can be used to extract the .hkl and .ins files required for further refinement with SHELXL. Recent developments in SHELXL facilitate refinement against neutron diffraction data, the treatment of H atoms, the determination of absolute structure, the input of partial structure factors and the refinement of twinned and disordered structures. SHELXL is available free to academics for the Windows, Linux and Mac OS X operating systems, and is particularly suitable for multiple-core processors.

  3. Crystal structure of pymetrozine

    Directory of Open Access Journals (Sweden)

    Youngeun Jeon

    2015-07-01

    Full Text Available The title compound, C10H11N5O {systematic name: 6-methyl-4-[(E-(pyridin-3-ylmethylideneamino]-4,5-dihydro-1,2,4-triazin-3(2H-one}, C10H11N5O, is used as an antifeedant in pest control. The asymmetric unit comprises two independent molecules, A and B, in which the dihedral angles between the pyridinyl and triazinyl ring planes [r.m.s. deviations = 0.0132 and 0.0255 ] are 11.60 (6 and 18.06 (4°, respectively. In the crystal, N—H...O, N—H...N, C—H...N and C—H...O hydrogen bonds, together with weak π–π interactions [ring-centroid separations = 3.5456 (9 and 3.9142 (9 Å], link the pyridinyl and triazinyl rings of A molecules, generating a three-dimensional network.

  4. High-pressure syntheses, crystal structures, and thermal behaviour of {beta}-RE(BO{sub 2}){sub 3} (RE = Nd, Sm, Gd)

    Energy Technology Data Exchange (ETDEWEB)

    Emme, H.; Heymann, G.; Haberer, A.; Huppertz, H. [Ludwig-Maximilians-Univ. Muenchen (Germany). Dept. Chemie und Biochemie

    2007-06-15

    The compounds {beta}-RE(BO{sub 2}){sub 3} [RE = Nd (neodymium meta-borate), Sm (samarium meta-borate) and Gd (gadolinium meta-borate)] were synthesized under high-pressure and high-temperature conditions in a Walker-type multianvil apparatus at 3.5 GPa (Nd), 7.5 GPa (Sm, Gd) and 1050 C. The crystal structures were determined by single crystal X-ray diffraction data collected at r. t. (Sm, Gd) and at -73 C (Nd), respectively. The structures are isotypic with the already known ambient-pressure phases {beta}-RE(BO{sub 2}){sub 3} (RE = (Tb, Dy)) and the high-pressure phases {beta}-RE(BO{sub 2}){sub 3} (RE = Ho.Lu). (orig.)

  5. Atomic, Crystal, Elastic, Thermal, Nuclear, and Other Properties of Beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, A

    2006-02-01

    This report is part of a series of documents that provide a background to those involved in the construction of beryllium components and their applications. This report is divided into five sub-sections: Atomic/Crystal Structure, Elastic Properties, Thermal Properties, Nuclear Properties, and Miscellaneous Properties. In searching through different sources for the various properties to be included in this report, inconsistencies were at times observed between these sources. In such cases, the values reported by the Handbook of Chemistry and Physics was usually used. In equations, except where indicated otherwise, temperature (T) is in degrees Kelvin.

  6. Temperature dependence of the crystal structure and g-values of trans-diaquabis(methoxyacetato)copper(II): evidence for a thermal equilibrium between complexes with tetragonally elongated and compressed geometries.

    Science.gov (United States)

    Simmons, Charles J; Stratemeier, Horst; Hitchman, Michael A; Reinen, Dirk; Masters, Vanessa M; Riley, Mark J

    2011-06-06

    The crystal structures of trans-diaquabis(methoxyacetato)copper(II) and the isostructural nickel(II) complex have been determined over a wide temperature range. In conjunction with the reported behavior of the g-values, the structural data suggest that the copper(II) compound exhibits a thermal equilibrium between three structural forms, two having orthorhombically distorted, tetragonally elongated geometries but with the long and intermediate bonds to different atoms, and the third with a tetragonally compressed geometry. This is apparently the first reported example of a copper(II) complex undergoing an equilibrium between tetragonally elongated and compressed forms. The optical spectrum of single crystals of the copper(II) compound is used to obtain metal-ligand bonding parameters which yield the g-values of the compressed form of the complex and hence the proportions of the complex in each structural form at every temperature. When combined with estimates of the Jahn-Teller distortions of the different forms, the latter produce excellent agreement with the observed temperature dependence of the bond lengths. The behavior of an infrared combination band is consistent with such a thermal equilibrium, as is the temperature dependence of the thermal ellipsoid parameters and the XAFS. The potential surfaces of the different forms of the copper(II) complex have been calculated by a model based upon Jahn-Teller coupling. It is suggested that cooperative effects may cause the development of the population of tetragonally compressed complexes, and the crystal packing is consistent with this hypothesis, though the present model may oversimplify the diversity of structural forms present at high temperature. © 2011 American Chemical Society

  7. Manufacturing, structure and properties of recycled polyethylene terephthalate /liquid crystal polymer/montmorillonite clay nanocomposites

    Science.gov (United States)

    Japins, Guntis; Berzina, Rita; Zicans, Janis; Merijs Meri, Remo; Ivanova, Tatjana; Kalkis, Valdis; Reinholds, Ingars

    2013-12-01

    Polyethylene terephthalate (PET)/liquid crystal polymer (LCP)/monthmorillonite clay (MMT) compositions were obtained by melt mixing. Their mechanical, structural, rheological and thermal properties were investigated.

  8. Synthesis, Crystal Structure, Vibrational Spectroscopy and Thermal Behavior of the First Alkali Metal Hydrated Hexaborate: K2[B6O9(OH)2

    Institute of Scientific and Technical Information of China (English)

    LI,Hong-Juan; LIU,Zhi-Hong; SUN,Li-Mei

    2007-01-01

    New hydrated potassium hexaborate K2[B6O9(OH)2] has been synthesized under mild solvothermal conditions.The structure was determined by single-crystal X-ray diffraction and further characterized by FT-IR, Raman spectra and DTA-TG. It crystallizes in the monoclinic system with space group P21/n, a=0.9036(2) nm, b=0.66052(18)nm, c= 1.5997(4) nm, β=91.862(4)°, V=0.9543(4) nm3 and Z=4. Its crystal structure consists of K-O polyhedra and 1-D stepped polyborate chains constructed by new [B6O9(OH)2]2- fundamental building blocks. 1-D polyborate chains contain 3,8-membered boron rings. Adjacent chains are further linked via H-bonding interactions into 2-D layers. The K+ cations reside not only between the layers but also in the 8-membered boron rings of the chains,compensating the negative charges of the borate chains and holding the layers together into the 3-D structure through bonding with oxygen atoms of the chains.

  9. Hydrothermal Synthesis,Crystal Structure and Thermal Stability of a Supramolecular Lead(II) Complex with 4-Nitrobenzoic Acid and 1,10-Phenanthroline

    Institute of Scientific and Technical Information of China (English)

    徐相君; 吴向阳; 徐婉珍; 周威; 闫永胜

    2012-01-01

    A new complex [Pb(phen)2(4-NBA)]2·2(NO3)·H2O(phen = 1,10-phenanthroline,4-NBA = 4-nitrobenzoate) has been hydrothermally synthesized and structurally determined by single-crystal X-ray diffraction,elemental analyses and IR spectroscopy.The complex crystallizes in monoclinic,space group P21/c with a = 13.416(3),b = 14.065(3),c = 16.845(3)(A°) ,β = 110.55(3)o,V = 2976.5(10)(A°)^3,Z = 2,Dc = 1.796 g/cm^3,F(000) = 1564,GOOF = 0.962,the final R = 0.0686 and wR = 0.1746.The crystal structure shows that the lead ion is coordinated with two carboxylate O atoms from the 4-NBA anion,and four N atoms from two phen molecules,forming a slightly distorted pentagonalbipyramidal coordination geometry.It is further extended by various supramo-lecular interactions to form a three-dimensional supramolecular network.The TG analysis result shows that this complex begins decomposing at 30 ℃ and decompounding completely at 733 ℃.

  10. The influence of structural factors on the composition, spectral-luminescent properties and thermal stability of zinc(II) bis(dipyrromethenate)s crystal solvates with amines

    Science.gov (United States)

    Guseva, G. B.; Ksenofontov, A. A.; Antina, E. V.

    2017-02-01

    It was found that 3,3‧-, 2,3‧- and 2,2‧-zinc(II) bis(dipyrromethenate)s ([Zn2L2]) form stable supramolecular complexes with aromatic and aliphatic amines (X - pyridine (Py), N,N-dimethylmethanamide (DMF), diethylamine (DEA) and triethylamine (TEA)) of the composition [Zn2L2(X)n]. Composition, stability and spectral-luminescent properties of the [Zn2L2(X)n] crystal solvates were studied by means of FTIR, PXRD, thermal, mass spectral, absorption, and fluorescence analyses. Spectroscopic studies showed that the quantum yield (φ) of [Zn2L2(Х)n] in cyclohexane is much lower (to ∼ 1.4-4.0 times) than φ for the [Zn2L2]. Crystal solvates are stable up to a temperature ∼367.35-427.55 K. It is demonstrated, that the high interactions energies (Znsbnd N) in [Zn2L2(X)n] supramolecular complexes are the main cause of the fluorescence quenching of [Zn2L2] luminophores in the presence of electron-donor molecules. The obtained results are of interest for the development on the basis of [Zn2L2] of a new fluorescent sensors of the electron donor molecules.

  11. Structural colours through photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    McPhedran, R.C.; Nicorovici, N.A.; McKenzie, D.R.; Rouse, G.W.; Botten, L.C.; Welch, V.; Parker, A.R.; Wohlgennant, M.; Vardeny, V

    2003-10-01

    We discuss two examples of living creatures using photonic crystals to achieve iridescent colouration. The first is the sea mouse (Aphroditidae, Polychaeta), which has a hexagonal close packed structure of holes in its spines and lower-body felt, while the second is the jelly fish Bolinopsis infundibulum, which has an oblique array of high index inclusions in its antennae. We show by measurements and optical calculations that both creatures can achieve strong colours despite having access only to weak refractive index contrast.

  12. Optically induced structural phase transitions in ion Coulomb crystals

    DEFF Research Database (Denmark)

    Horak, Peter; Dantan, Aurelien Romain; Drewsen, Michael

    2012-01-01

    , such as body-centered cubic and face-centered cubic, can be suppressed by a proper choice of the potential depth and periodicity. Furthermore, by varying the harmonic trap parameters and/or the optical potential in time, controlled transitions between crystal structures can be obtained with close to unit......We investigate numerically the structural dynamics of ion Coulomb crystals confined in a three-dimensional harmonic trap when influenced by an additional one-dimensional optically induced periodical potential. We demonstrate that transitions between thermally excited crystal structures...

  13. The effect of linear imperfection in [001] direction on the thermal properties of silver crystal

    Directory of Open Access Journals (Sweden)

    J Davoodi

    2013-09-01

    Full Text Available  The aim of this investigation was to calculate the thermal properties of silver crystal in the presence of linear imperfection. The simulations were performed by molecular dynamics simulation technique in NPT as well as NVT ensemble based on quantum Sutton-Chen many body potential. The thermal properties including cohesive energy, melting temperature, isobaric heat capacity and thermal expansion of imperfect silver crystal were calculated and compared to those of the perfect crystal. Moreover, the quantities such as radial distribution function, order parameter and lindemann index were calculated in order to obtain information on crystal structure and disorder in atoms. All calculations were done both with liner imperfection in [001] direction and without imperfection at different temperature. The simulation results show that cohesive energy, linear thermal expansion coefficient increase and melting temperature, latent heat of fusion decrease with increasing linear imperfection. Also, the results show that linear imperfection has no effect on the heat capacity.

  14. THE CRYSTAL STRUCTURE OF ANTIMONY (III) SULFOBROMIDE, SBSBR,

    Science.gov (United States)

    ANTIMONY COMPOUNDS, *SULFUR COMPOUNDS, CRYSTAL STRUCTURE , CRYSTAL STRUCTURE , BROMIDES, SYMMETRY(CRYSTALLOGRAPHY), FOURIER ANALYSIS, MOLECULAR STRUCTURE, CRYSTAL LATTICES, CHEMICAL BONDS, X RAY DIFFRACTION.

  15. Studies on growth, crystal structure and characterization of novel organic nicotinium trifluoroacetate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Dhanaraj, P.V. [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Rajesh, N.P., E-mail: rajeshnp@hotmail.com [Centre for Crystal Growth, SSN College of Engineering, Kalavakkam 603 110 (India); Sundar, J. Kalyana; Natarajan, S. [Department of Physics, Madurai Kamaraj University, Madurai 625 021 (India); Vinitha, G. [Department of Physics, Crescent Engineering College, Chennai 600 048 (India)

    2011-09-15

    Highlights: {yields} Good quality crystals of nicotinium trifluoroacetate in monoclinic system were grown for first time. {yields} Nicotinium trifluoroacetate crystal exhibits third order nonlinear optical properties. {yields} The optical spectrum of nicotinium trifluoroacetate crystal reveals the wide transmission in the entire range with cutoff wavelength at 286 nm. {yields} Nicotinium trifluoroacetate is a low dielectric constant material. - Abstract: An organic material, nicotinium trifluoroacetate (NTF) was synthesized and single crystals in monoclinic system were grown from aqueous solution for the first time. Its solubility and metastable zone width were estimated. The crystal structure of NTF was analyzed to reveal the molecular arrangements and the formation of hydrogen bonds in the crystal. High-resolution X-ray diffraction rocking curve measurements were performed to analyze the structural perfection of the grown crystals. Functional groups in NTF were identified by Fourier transform infrared spectral analysis. Thermal behaviour and stability of NTF were studied by thermogravimetric and differential thermal analysis and differential scanning calorimetry. Mechanical and dielectric properties of NTF crystals were analyzed. Optical studies reveal that NTF crystals are transparent in the wavelength range 286-1100 nm. The third order nonlinear optical parameters of NTF were derived by the Z-scan technique.

  16. Preparation,Crystal Structure and Thermal Analyses of a Nitrogen-rich Coordination Compound [Co(DAT)6](PA)2·4H2O

    Institute of Scientific and Technical Information of China (English)

    CUI Yan; ZHANG Jian-Guo; ZHANG Tong-Lai; YANG Li; ZANG Yan; SHU Yuan-Jie

    2008-01-01

    A new coordination compound [Co(DAT)6](PA)2·4H2O has been prepared by using 1,5-diaminotetrazole(DAT)as ligands and picrate(PA)as acidic anions,and structurally characterized by X-ray single crystal diffraction,ele-mental analysis and FT-IR spectroscopy.The cobalt(Ⅱ)cation coordinates with six N atoms from six bulky DAT molecules to form a six-coordinated and slightly distorted octahedral configuration.The coordination cation is situ-ated between two PA anions whose benzene-ring planes are parallel to each other.The coordination cation and the lecular units are linked together by the intermolecular hydrogen bonds to form the crystal structure,in the formation investigated by using DSC,TG-DTG and FT-IR analyses.The kinetic parameters of the first exothermic process of the title compound were studied by applying the Kissinger's and Ozawa-Doyle's methods.

  17. Pattern information extraction from crystal structures

    OpenAIRE

    Okuyan, Erhan

    2005-01-01

    Cataloged from PDF version of article. Determining crystal structure parameters of a material is a quite important issue in crystallography. Knowing the crystal structure parameters helps to understand physical behavior of material. For complex structures, particularly for materials which also contain local symmetry as well as global symmetry, obtaining crystal parameters can be quite hard. This work provides a tool that will extract crystal parameters such as primitive vect...

  18. Stishovite: Thermal Dependence of the Crystal Habit.

    Science.gov (United States)

    Sclar, C B; Carrison, L C; Cocks, G G

    1964-05-15

    The crystal habit of stishovite changes with the temperature of crystallization at a pressure of about 120 kb. Below 600 degrees C it is bipyramidal; between 600 degrees and 900 degrees C it is granular; and above 900 degrees C it is acicular. This temperature dependence of the crystal habit of stishovite may constitute a highpressure geological thermometer which could indicate limiting values for the peak temperatures that prevailed at craters of meteoritic origin in highly siliceous rocks. It suggests that natural acicular stishovite from the rim sandstone at Meteor Crater, Arizona, crystallized at temperatures above 900 degrees C.

  19. Crystal structure of nonadentate tricompartmental ligand derived from pyridine-2,6-dicarboxylic acid: Spectroscopic, electrochemical and thermal investigations of its transition metal(II) complexes

    Science.gov (United States)

    Vadavi, Ramesh S.; Shenoy, Rashmi V.; Badiger, Dayananda S.; Gudasi, Kalagouda B.; Devi, L. Gomathi; Nethaji, Munirathinam

    2011-07-01

    The coordinating behavior of a new dihydrazone ligand, 2,6-bis[(3-methoxysalicylidene)hydrazinocarbonyl]pyridine towards manganese(II), cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) has been described. The metal complexes were characterized by magnetic moments, conductivity measurements, spectral (IR, NMR, UV-Vis, FAB-Mass and EPR) and thermal studies. The ligand crystallizes in triclinic system, space group P-1, with α = 98.491(10)°, β = 110.820(10)° and γ = 92.228(10)°. The cell dimensions are a = 10.196(7) Å, b = 10.814(7) Å, c = 10.017(7) Å, Z = 2 and V = 1117.4(12). IR spectral studies reveal the nonadentate behavior of the ligand. All the complexes are neutral in nature and possess six-coordinate geometry around each metal center. The X-band EPR spectra of copper(II) complex at both room temperature and liquid nitrogen temperature showed unresolved broad signals with giso = 2.106. Cyclic voltametric studies of copper(II) complex at different scan rates reveal that all the reaction occurring are irreversible.

  20. Crystal structure of gold hydride

    Energy Technology Data Exchange (ETDEWEB)

    Degtyareva, Valentina F., E-mail: degtyar@issp.ac.ru

    2015-10-05

    Highlights: • Volume expansion of metal hydrides is due to the increase in the s-band filling. • AuH structure is similar to that of Hg having one more s electron compared to Au. • Structure stability of both Hg and AuH is governed by the Hume-Rothery rule. - Abstract: A number of transition metal hydrides with close-packed metal sublattices of fcc or hcp structures with hydrogen in octahedral interstitial positions were obtained by the high-pressure-hydrogen technique described by Ponyatovskii et al. (1982). In this paper we consider volume increase of metals by hydrogenation and possible crystal structure of gold hydride in relation with the structure of mercury, the nearest neighbor of Au in the Periodic table. Suggested structure of AuH has a basic tetragonal body-centered cell that is very similar to the mercury structure Hg-t I 2. The reasons of stability for this structure are discussed within the model of Fermi sphere–Brillouin zone interactions.

  1. Synthesis, crystal structures, and thermal and spectroscopic properties of two Cd(II) metal-organic frameworks with a versatile ligand

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jia-Ming; He, Kun-Huan; Shi, Zhong-Feng [Qinzhou Univ. (China). Guangxi Colleges and Univs. Key Lab. of Beibu Gulf Oil and Natural Gas Resource Effective Utilization; Gao, Hui-Yuan; Jiang, Yi-Min [Guangxi Normal Univ., Guilin (China). Key Lab. for the Chemistry and Molecular Engineering of Medicinal Resources

    2016-11-01

    Two new metal-organic frameworks, namely, [Cd(L)(H{sub 2}O)]{sub n} (1) and {[Cd_0_._5(L)(4,4"'-bipy)_0_._5][Cd_0_._5(H_2O)(4,4"'-bipy)_0_._5].H_2O}{sub n} (2), where H{sub 2}L = N-pyrazinesulfonyl-glycine and 4,4{sup '}-bipy = 4,4{sup '}-bipyridine, have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental, thermogravimetric, and photoluminescent analysis. X-ray diffraction crystallographic analyses indicate that 1 displays a distorted octahedral metal coordination in a 3-connected (4, 8{sup 2}) topology, while the molecular structure of 2 has a 4-connected (4, 4) topology with two perfectly octahedrally coordinated Cd centers. The L{sup 2-} ligand serves as a N,N,O-tridentate, μ{sub 2}-pyrazine-bridging, and μ{sub 2}-carboxylate-bridging ligand in 1, and as a N,O-bidentate and μ{sub 2}-carboxylate-bridging ligand in 2. In the crystal, a 3D supramolecular architecture is formed by O-H..O hydrogen bond interactions in 1, but through O-H..O as well as π..π stacking in 2. The two compounds show intense fluorescence in the solid state at room temperature.

  2. Reduction of thermal conductivity by nanoscale 3D phononic crystal.

    Science.gov (United States)

    Yang, Lina; Yang, Nuo; Li, Baowen

    2013-01-01

    We studied how the period length and the mass ratio affect the thermal conductivity of isotopic nanoscale three-dimensional (3D) phononic crystal of Si. Simulation results by equilibrium molecular dynamics show isotopic nanoscale 3D phononic crystals can significantly reduce the thermal conductivity of bulk Si at high temperature (1000 K), which leads to a larger ZT than unity. The thermal conductivity decreases as the period length and mass ratio increases. The phonon dispersion curves show an obvious decrease of group velocities in 3D phononic crystals. The phonon's localization and band gap is also clearly observed in spectra of normalized inverse participation ratio in nanoscale 3D phononic crystal.

  3. Thermal properties of single-walled carbon nanotube crystal

    Institute of Scientific and Technical Information of China (English)

    Hu Li-Jun; Liu Ji; Liu Zheng; Qiu Cai-Yu; Zhou Hai-Qing; Sun Lian-Feng

    2011-01-01

    In this work,the thermal properties of a single-walled carbon nanotube (SWCNT) crystal are studied. The thermal conductivity of the SWCNT crystal is found to have a linear dependence on temperature in the temperature range from 1.9 K to 100.0 K. In addition,a peak (658 W/mK) is found at a temperature of about 100.0 K. The thermal conductivity decreases gradually to a value of 480 W/mK and keeps almost a constant in the temperature range from 100.0 K to 300.0 K. Meanwhile,the specific heat shows an obvious linear relationship with temperature in the temperature range from 1.9 K to 300.0 K. We discuss the possible mechanisms for these unique thermal properties of the single-walled carbon nanotube crystal.

  4. Brine Inclusions Migration in Intact Salt Crystals under Thermal Gradient

    Science.gov (United States)

    Caporuscio, F.; Boukhalfa, H.

    2013-12-01

    The behavior of water contained in rock salt under the influence of thermal gradients is critical to the performance of salt as a medium for the disposal of nuclear waste. Water contained in salt can be present as discrete inclusions within intact salt crystals, at the interface between salt crystals and aggregates, and also as hydration water and structural water present in accessory minerals present in salt. Water content in pure halite salt usually rages from 0.1 to 0.5 wt. % but is significantly higher in clay rich salt, for which water content can be up to several wt. %. Under the influence of thermal gradients brine inclusions and water associated to the accessory mineral is mobilized. Previous investigations have shown brine inclusions tend to move towards the heat source through a mechanism that involves the dissolution of salt at the hot face of the brine inclusion and its precipitation at the colder side of the inclusion. Uncertainties remain on the exact parameters that define the rate of brine migration and whether it truly migrates to towards the heat source. We performed studies under controlled thermal gradients to examine the behavior of brine inclusions in single salt crystals obtained from the underground salt mine at the Waste Isolation Power Plant (WIPP). We found that the behavior of the brine inclusions under thermal gradients is dependent on the thermal gradient magnitude and the nature of the inclusion. Full inclusions (liquid only) migrate predominantly towards the heat source, but when the inclusions are large and close to the surface they fracture the salt and release water near the surface. Inclusions that migrate towards the heat source migrate through a mechanism that involves the dissolution of salt at the hot side of the inclusion and its deposition along the migration path. SEM analysis of the migration pathways shows that brine migrates through the creation of a network of square shaped hollow channels of about 10 micron diameter

  5. Crystal growth, structural, spectral, thermal, linear and nonlinear optical characterization of a new organic nonlinear chiral compound: L-tryptophan-fumaric acid-water (1/1/1) suitable for laser frequency conversion

    Science.gov (United States)

    Peer Mohamed, M.; Jayaprakash, P.; Nageshwari, M.; Rathika Thaya Kumari, C.; Sangeetha, P.; Sudha, S.; Mani, G.; Lydia Caroline, M.

    2017-08-01

    A new organic active nonlinear optical crystal L-tryptophan fumaric acid water (1/1/1), (C15H17N2 O7. H2O)(LTFAW), consisting of zwitterion tryptophan molecule in conjunction with a fumaric acid molecule and a water molecule was grown by slow solvent evaporation technique from aqueous solution. The organic chromophore crystallizes from water in its zwitterions exhibiting tabular habit in monoclinic system with acentric space group C2 (Z = 4). The sharp peaks observed in Powder X-ray diffractogram depicts the crystalline nature. The presence of functional groups in the grown crystal was analyzed using FT-IR spectrum. The carbon and hydrogen environment in molecular structure was investigated using FT-NMR technique using deuterated DMSO solution. Ultraviolet-visible spectral analysis reveal that the crystal possess lower cut-off wavelength down to 275 nm, is a key factor to exhibit Second Harmonic Generation (SHG) signal. The direct optical band gap is evaluated to be 5.28 eV from the UV absorption profile. The evaluation of optical constants by employing UV-visible absorbance data such as, extinction coefficient, reflectance, refractive index, optical conductivity are supportive towards good performance as NLO devices. Temperature of decomposition was investigated using thermogravimetric analysis/differential thermal analysis techniques (TG/DTA). The luminescence profile exhibited two peaks (362 nm, 683 nm) due to the donation of protons from carboxylic group to amino group. The nonlinear optical behavior from the noncentrosymmetric crystal was observed by the generation of frequency doubled (2ω) optical radiation when subjected to pulsed Nd:YAG laser (1064 nm, 10 ns, 10 Hz) using Kurtz-Perry method. The variation of dielectric constant (εʹ) and dielectric loss (εʹʹ) vs. Log f for the title compound was analysed at a few selected temperatures and frequencies.

  6. Thermal Conductivity and Liquid Crystal Thermometers.

    Science.gov (United States)

    Edge, R. D., Ed.

    1993-01-01

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

  7. Novel photonic crystal cavities and related structures.

    Energy Technology Data Exchange (ETDEWEB)

    Luk, Ting Shan

    2007-11-01

    The key accomplishment of this project is to achieve a much more in-depth understanding of the thermal emission physics of metallic photonic crystal through theoretical modeling and experimental measurements. An improved transfer matrix technique was developed to enable incorporation of complex dielectric function. Together with microscopic theory describing emitter radiative and non-radiative relaxation dynamics, a non-equilibrium thermal emission model is developed. Finally, experimental methodology was developed to measure absolute emissivity of photonic crystal at high temperatures with accuracy of +/-2%. Accurate emissivity measurements allow us to validate the procedure to treat the effect of the photonic crystal substrate.

  8. Synthesis, Crystal Structure and Thermal Stability of a Saturated Dimeric Ce(Ⅲ)-chelated Complex Based on Benzoate and 1,10-Phenanthroline Ligands

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The title complex, [Ce(BA)3phen]2 (BA = benzoate, phen = 1,10-phenanthroline),was prepared by the reaction of Ce(NO3)3·6H2O, benzoic acid and 1,10-phenanthroline. The complex was characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra and TG-DTG techniques. The results show that the crystal is of triclinic, space group P(1) with a =10.912(2), b = 11.962(3), c = 12.474(3)(A), a = 104.889(3), β = 93.523(3), γ = 113.332(3)°,C66H46Ce2N4O12, Mr = 1366.90, V= 1420.2(6) (A)3, Z = 1, Dc = 1.598 g/cm3,μ = 1.652 mm-1, S =1.024 and F(000) = 682. The final R = 0.0391 and wR = 0.0947 for 4878 observed reflections with I > 2σ(1). The structure of the title complex consists of two Ce(C6H5COO)3(C12H8N2) units,forming a binuclear molecule. Each Ce(Ⅲ) is coordinated by two O atoms of one bidentate chelating carboxylate group, five O atoms of two bidentate bridging and two tridentate chelating-bridging carboxylate groups, and two N atoms of one 1,10-phenanthroline molecule to complete a distorted monocapped square antiprism geometry. Its thermogravimetric analysis was determined by TG-DTG techniques.

  9. Crystal structure of fiber structured pentacene thin films

    OpenAIRE

    2007-01-01

    This PhD thesis presents a technique based on the grazing incidence crystal truncation rod (GI-CTR) X-ray diffraction method used to solve the crystal structure of substrate induced fiber structured organic thin films. The crystal structures of pentacene thin films grown on technologically relevant gate dielectric substrates are reported. It is widely recognized, that the intrinsic charge transport properties in organic thin film transistors (OTFTs) depend strongly on the crystal structur...

  10. Crystal growth and structural analysis of zirconium sulphoselenide single crystals

    Indian Academy of Sciences (India)

    K R Patel; R D Vaidya; M S Dave; S G Patel

    2008-08-01

    A series of zirconium sulphoselenide (ZrSSe3–, where = 0, 0.5, 1, 1.5, 2, 2.5, 3) single crystals have been grown by chemical vapour transport technique using iodine as a transporting agent. The optimum condition for the growth of these crystals is given. The stoichiometry of the grown crystals were confirmed on the basis of energy dispersive analysis by X-ray (EDAX) and the structural characterization was accomplished by X-ray diffraction (XRD) studies. The crystals are found to possess monoclinic structure. The lattice parameters, volume, particle size and X-ray density have been carried out for these crystals. The effect of sulphur proportion on the lattice parameter, unit cell volume and X-ray density in the series of ZrSSe3– single crystals have been studied and found to decrease in all these parameters with rise in sulphur proportion. The grown crystals were examined under optical zoom microscope for their surface topography study. Hall effect measurements were carried out on grown crystals at room temperature. The negative value of Hall coefficient implies that these crystals are -type in nature. The conductivity is found to decrease with increase of sulphur content in the ZrSSe3– series. The electrical resistivity parallel to c-axis as well as perpendicular to -axis have been carried out in the temperature range 303–423 K. The results obtained are discussed in detail.

  11. Influence of microgravity on protein crystal structures

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Structural determination and comparison of microgravity and ground grown protein crystals have been carried out in order to investigate the effect of microgravity on the structure of protein crystals. Following the structural studies on the hen egg-white lysozyme cystals grown in space and on the ground, the same kind of comparative studies was performed with acidic phospholipase A2 crystals grown in different gravities. Based on the results obtained so far, a conclusion could be made that microgravity might not be strong enough to change the conformation of polypeptide chain of proteins, but it may improve the bound waters' structure, and this might be an important factor for microgravity to improve the protein crystal quality. In addition, the difference in the improvement between the two kinds of protein crystals may imply that the degree of improvement of a protein crystal in microgravity may be related to the solvent content in the protein crystal.

  12. Synthesis, characterization, crystal structure, and thermal analysis of 2-chloro-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl) acetamide

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, R. [University of Jammu, X-ray Crystallography Laboratory, Post-Graduate Department of Physics & Electronics (India); Nayak, P. S.; Narayana, B. [Mangalore University, Mangalagangotri, Department of Studies in Chemistry (India); Kant, R., E-mail: rkvk.paper11@gmail.com [University of Jammu, X-ray Crystallography Laboratory, Post-Graduate Department of Physics & Electronics (India)

    2015-12-15

    The title compound, C{sub 13}H{sub 14}O{sub 2}N{sub 3}Cl, has been synthesized by the reaction of chloroacetyl chloride with 4-aminoantipyrine in basic media and characterized by FT-IR, CHN elemental analysis, UV-Vis, TGA, DTA, DSC and single crystal X-ray diffraction. crystals are monoclinic, sp. gr. P2{sub 1}/c, a = 6.9994(6), b = 12.4035(13), c = 15.836(2) Å, β = 100.367(9)°, Z = 4. The crystal structure is stabilized by N–H···O and C–H···O interactions, the former interactions result in the formation of dimers corresponding to R{sub 2}{sup 2} (10) graphset motif and the dimers are further connected by C–H···O hydrogen bonding forming chains. In addition, the thermal stability of the compound was determined by TGA, DTA, DSC analysis, and absorption at λ{sub max} = 298 nm was determined by UV-Vis spectrophotometer.

  13. Thermal lensing in silver gallium selenide parametric oscillator crystals.

    Science.gov (United States)

    Marquardt, C L; Cooper, D G; Budni, P A; Knights, M G; Schepler, K L; Dedomenico, R; Catella, G C

    1994-05-20

    We performed an experimental investigation of thermal lensing in silver gallium selenide (AgGaSe(2)) optical parametric oscillator crystals pumped by a 2-µm laser at ambient temperature. We determined an empirical expression for the effective thermal focusing power in terms of the pump power, beam diameter, crystal length, and absorption coefficient. This relation may be used to estimate average power limitations in designing AgGaSe(2) optical parametric oscillators. We also demonstrated an 18% slope efficiency from a 2-µm pumped AgGaSe(2) optical parametric oscillator operated at 77 K, at which temperature thermal lensing is substantially reduced because of an increase in the thermal conductivity and a decrease in the thermal index gradient dn/dT. Cryogenic cooling may provide an additional option for scaling up the average power capability of a 2-µm pumped AgGaSe(2) optical parametric oscillator.

  14. Synthesis, spectral, thermal, crystal structure, Hirschfeld analysis of [bis(triamine)Cadimium(II)][Cadimum(IV)tetra-bromide] complexes and their thermolysis to CdO nanoparticles.

    Science.gov (United States)

    Warad, Ismail; Al-Rimawi, Fuad; Barakat, Assem; Affouneh, Saida; Shivalingegowda, Naveen; Lokanath, Neartur Krishnappagowda; Abu-Reidah, Ibrahim M

    2016-01-01

    The coordination chemistry of cadmium(II) with diamine ligands is of particular interest. The most common structure around cadmium(II) center in their complexes is tetrahedral, that is due the octet rule obeyed. Nevertheless, five and six-coordinated complexes are also well known. Now a day, many cadmium(II) complexes with chelate ligands were synthesized for their structural or applications properties. Antibacterial activities and DNA binding affinity of this class of cadmium complexes have attracted considerable interest. Cadmium(II) complexes in dicationic form with general formula [Cd(dien)2]CdBr4 complex 1 (dien = diethylenetriamine) and [Cd(dipn)2]CdBr4 complex 2 (dipn = diproylenetriamine) were prepared and elucidated there chemical structures by elemental analysis, UV-Vis, IR, TG and NMR, additionally complex 1 structure was solved by X-ray diffraction study. The Cd(II) cation is located in a slightly distorted octahedral geometry while Cd(IV) anion is in tetrahedral geometry. High stability of the synthesized complexes confirmed by TG. Thermolysis of complex 1 revealed the formation of pure cubic nanoparticles CdO which was deduced by spectral analysis. The average size of CdO nanoparticles was found to be ~60 nm. Two new Cd(II) complexes of general formula [Cd(N3)2]CdBr4 were made available. The structure of [Cd(dien)2]CdBr4 was confirmed by X-ray diffraction. Thermal, electro and spectral analysis were also investigated in this study. The direct thermolysis of such complexes formed a cubic CdO regular spherical nanoparticle with the ~60 nm average particle size.Graphical abstractORTEP for the complex 1.

  15. Crystal structure, magnetic, thermal behavior, and spectroscopic studies of two new bimetallic hydrogenselenites: [Cu2-xNix (HSeO3)2Cl2.4H2O], (x = 0.62; 0.91)

    Science.gov (United States)

    Hentech, I.; Zehani, K.; Kabadou, A.; Ben Salah, A.; Loukil, M.; Bessais, L.

    2016-08-01

    Two new iso-structural bimetallic hydrogenselenites [Cu2-xNix(HSeO3)2Cl2.4H2O] (x = 0.62; 0.91) have been synthesized from solution and characterized by single-crystal and powder X-ray diffraction. They crystallized in the orthorhombic Pnma space group with the following lattice parameters: for Cu1.09Ni0.91(HSeO3)2Cl2.4H2O: a = 9.0931 (2) Å, b = 17.7717 (4) Å, c = 7.1620 (2) Å, Z = 4, and for Cu1.38Ni0.62(HSeO3)2Cl2.4H2O: a = 9.0931 (4) Å, b = 17.7467 (7) Å, c = 7.1717 (3) Å; Z = 4. The crystal structure of this compound consists by a three-dimensional framework, but it may be described as a bi-dimensional structure consisting of layers, parallel to the (010) plane formed by two types of (Cu/Ni) octahedral and (HSeO3)- trigonal pyramids. The magnetic measurement, thermal and spectroscopic studies were performed for these compounds. The magnetic results reveal the appearance of a weak ferromagnetic behavior at low temperature (Tc = 16 K for x = 0.91 and 18.8 K for x = 0.62). The DSC analysis enabled us to locate two endothermic peaks. The first peak can be attributed to a completely dehydration of the material, in this transformation, the compounds undergo a structural phase transition which can favor a non-centrosymmetric phase at high temperature confirmed by the thermodiffractograms measurement. The second peak for these samples is due to the ferro-paraelectric phase transition which can be explained by an order- disorder transition.

  16. 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.

  17. Cyanide bridged hetero-metallic polymeric complexes: Syntheses, vibrational spectra, thermal analyses and crystal structures of complexes [M(1,2-dmi)2Ni(μ-CN)4]n (M = Zn(II) and Cd(II))

    Science.gov (United States)

    Kürkçüoğlu, Güneş Süheyla; Sayın, Elvan; Şahin, Onur

    2015-12-01

    Two cyanide bridged hetero-metallic complexes of general formula, [M(1,2-dmi)2Ni(μ-CN)4]n (1,2-dmi = 1,2-dimethylimidazole and M = Zn(II) or Cd(II)) have been synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, single crystal X-ray diffraction, thermal analyses and elemental analyses. The crystallographic analyses reveal that the complexes, [Zn(1,2-dmi)2Ni(μ-CN)4] (1) and [Cd(1,2-dmi)2Ni(μ-CN)4] (2), have polymeric 2D networks. In the complexes, four cyanide groups of [Ni(CN)4]2- coordinated to the adjacent M(II) ions and distorted octahedral geometries of complexes are completed by two nitrogen atoms of trans 1,2-dmi ligands. The structures of 1 and 2 are similar and linked via intermolecular hydrogen bonding, C-H⋯Ni interactions to give rise to 3D networks. Vibration assignments are given for all the observed bands and the spectral features also supported to the crystal structures of heteronuclear complexes. The FT-IR and Raman spectra of the complexes are very much consistent with the structural data presented.

  18. Crystal Growth and Glass-Like Thermal Conductivity of Ca3RE2(BO34 (RE = Y, Gd, Nd Single Crystals

    Directory of Open Access Journals (Sweden)

    L. V. Gudzenko

    2017-03-01

    Full Text Available Crystal growth and thermal properties of binary borates, Ca3RE2(BO34 (RE = Y, Gd, Nd, are considered promising crystals for laser applications. These single crystals were grown by the Czochralski method. The crystal and defect structure were characterized. Volumetric chemical methods without prior separation of the components were developed and applied for the determination of the dependence of chemical compositions of the crystals on the growth conditions. The thermal conductivity was investigated in the 50–300 K range. The character of the temperature dependence of thermal conductivity was found to be similar to that of glass. The possible reasons of the observed features of the thermal conductivity were analyzed.

  19. Predicting crystal structures of organic compounds.

    Science.gov (United States)

    Price, Sarah L

    2014-04-07

    Currently, organic crystal structure prediction (CSP) methods are based on searching for the most thermodynamically stable crystal structure, making various approximations in evaluating the crystal energy. The most stable (global minimum) structure provides a prediction of an experimental crystal structure. However, depending on the specific molecule, there may be other structures which are very close in energy. In this case, the other structures on the crystal energy landscape may be polymorphs, components of static or dynamic disorder in observed structures, or there may be no route to nucleating and growing these structures. A major reason for performing CSP studies is as a complement to solid form screening to see which alternative packings to the known polymorphs are thermodynamically feasible.

  20. High dno/dT liquid crystals and their applications in a thermally tunable liquid crystal photonic crystal fiber

    DEFF Research Database (Denmark)

    Li, J.; Gauza, S.; Wu, S.-T.

    2006-01-01

    crystal mixtures, designated as UCF-1 and UCF-2. The dn(o)/dT of UCF-1 is similar to 4x higher than that of 5CB at room temperature. By infiltrating UCF-1 into the air holes of a three-rod core photonic crystal fiber, we demonstrate a thermally tunable photonic bandgap fiber with tuning sensitivity of 27...

  1. Thermal conductivity enhancement in thermal grease containing different CuO structures.

    Science.gov (United States)

    Yu, Wei; Zhao, Junchang; Wang, Mingzhu; Hu, Yiheng; Chen, Lifei; Xie, Huaqing

    2015-01-01

    Different cupric oxide (CuO) structures have attracted intensive interest because of their promising applications in various fields. In this study, three kinds of CuO structures, namely, CuO microdisks, CuO nanoblocks, and CuO microspheres, are synthesized by solution-based synthetic methods. The morphologies and crystal structures of these CuO structures are characterized by field-emission scanning electron microscope and X-ray diffractometer, respectively. They are used as thermal conductive fillers to prepare silicone-based thermal greases, giving rise to great enhancement in thermal conductivity. Compared with pure silicone base, the thermal conductivities of thermal greases with CuO microdisks, CuO nanoblocks, and CuO microspheres are 0.283, 0256, and 0.239 W/mK, respectively, at filler loading of 9 vol.%, which increases 139%, 116%, and 99%, respectively. These thermal greases present a slight descendent tendency in thermal conductivity at elevated temperatures. These experimental data are compared with Nan's model prediction, indicating that the shape factor has a great influence on thermal conductivity improvement of thermal greases with different CuO structures. Meanwhile, due to large aspect ratio of CuO microdisks, they can form thermal networks more effectively than the other two structures, resulting in higher thermal conductivity enhancement.

  2. Synthesis, crystal structure determination, thermal and magnetic properties of the new Cu0.73Ni0.27(HSeO3)2 compound

    Science.gov (United States)

    Hentech, I.; Zehani, K.; Kabadou, A.; Ben Salah, A.; Loukil, M.; Bessais, L.

    2017-01-01

    A novel three-dimensional Cu0.73Ni0.27(HSeO3)2 compound was prepared from an aqueous solution. This compound crystallizes in the monoclinic system with P21/n space group and with the following cell parameters: a=6.4379(3) Å; b=7.3555(3) Å; c=5.7522(3) Å; β=93.4341(1)°; V=271.90(2) Å3 and Z=2. The reported material has been structurally characterized by X-ray powder diffraction and confirmed by scanning electron microscope and energy dispersive spectroscopy (MEB/EDS) analysis. The copper/nickel atom is surrounded by an octahedron coordination of oxygen atoms from sex hydrogenoselenites anions. The presence of (HSeO3)- has been further confirmed by IR spectroscopy and this compound exhibits a phase transition at 356 K, this transition has been detected by differential scanning calorimetry and TG-DTA measurement. The magnetic property of this material was determined. The ferromagnetic ordering is further confirmed by the magnetic field dependence of the magnetization (Hysteresis loop) at 10 K. The substitution of Cu by Ni induces a ferro-paramagnetic transition at T=31 K. Field cooled (FC) and Zero field cooled (ZFC) magnetization measurements under an applied field of 100 Oe in the temperature range of 10-300 K were performed. These measurements have been resulted the blocking temperature (TB) at around 25 K.

  3. Thermal Structure Design of CCL

    Institute of Scientific and Technical Information of China (English)

    LI; Chun-guang; LI; Jin-hai

    2013-01-01

    CCL is a kind of proton Linac accelerator which is applied for 80 MeV.It has high proton energy and strong electric field that raises the temperature of the cavity.If cooling problems not well solved,it leads to cavity deformation,thus changes the resonance frequency of cavity.As a result it can’t work normally.Thermal structure design of CCL involves heat,structure and high frequency analysis.According to

  4. Crystal structure, thermal studies, Hirshfeld surface analysis, vibrational and DFT investigation of organic-inorganic hybrid compound [C9H6NOBr2]2CuBr4·2H2O

    Science.gov (United States)

    Mesbeh, Radhia; Hamdi, Besma; Zouari, Ridha

    2016-12-01

    Single crystals of a hybrid organic/inorganic material with the formula [C9H6NOBr2]2CuBr4·2H2O were studied by X-ray diffraction. The compound crystallizes in the monoclinic system, space group C2/c with the following unit cell parameters: a = 7.8201 (12) Ǻ, b = 18.203 (3) Ǻ, c = 19.486 (3) Ǻ, β = 98.330 (5)°, Z = 4, V = 2744.6 (7) Ǻ3. Crystal structure was solved with a final R = 5.66% for 3483 independent reflections. The atomic arrangement shows an alternation of organic and inorganic layers. Between layers, the cohesion is performed via Osbnd H⋯Br, Csbnd H⋯Br, Nsbnd H⋯Br, Nsbnd H⋯O and Osbnd H⋯O hydrogen bending. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) measurements have been carried out on [C9H6NOBr2]2CuBr4·2H2O crystal in the temperature range between 50 and 500 °C. The assignment of the observed bands in the solid state FTIR and Raman spectra of the compound was assisted by the theoretically predicted frequencies and compared with data previously reported for similar compounds. The theoretical geometrical parameters in the ground state have been investigated by density functional theory (DFT) with the B3LYP/LanL2DZ level of theory. The optical properties were investigated by optical absorption and show two bands at 279, 300 nm. The percentages of hydrogen bonding interactions are analyzed by Fingerprint plots of Hirshfeld surface.

  5. Hot Views on Cold Crystals: The Application of Thermal Imaging in Cryocrystallography

    Science.gov (United States)

    Snell, Eddie

    2003-01-01

    We have used thermal imaging techniques to visualize the cryocooling processes of macromolecular crystals. Cryocooling is a common technique used for structural data collection to reduce radiation damage in intense X-ray beams and decrease the thermal motion of the atoms. From the thermal images it was clear that during cryocooling a cold wave progresses through a crystal starting at the face closest to the origin of the cold stream and ending at the point furthest away. As an extension to this work, we used thermal imaging to study small crystals, held in a cryo-loop, in the presence of vitrified mother liquor. The different infrared transmission and reflectance properties of the crystal in comparison to the mother liquor surrounding it are thought to be the parameter that produces the contrast that makes the crystal visible. An application of this technology may be the determination of the exact location of small crystals in a cryo-loop for automated structural genomics studies. Data from initial tests in support of application development was recorded for lysozyme crystals and for bFGF/dna complex crystals, which were cryocooled and imaged in large loops, both with visible light and with infrared radiation. The crystals were clearly distinguished from the vitrified solution in the infrared spectrum, while in the case of the bFGF/dna complex the illumination had to be carefully manipulated to make the crystal visible in the visible spectrum. These results suggest that the thermal imaging may be more sensitive than visual imaging for automated location of small crystals. However, further work on small crystals robotically mounted at SSRL did not clearly visualize those crystals. The depth of field of the camera proved to be limiting and a different cooling geometry was used, compared to the previous, successful experiments. Analysis to exploit multiple images to improve depth of field and experimental work to understand cooling geometry effects is ongoing. These

  6. Thermally Driven Photonic Actuator Based on Silica Opal Photonic Crystal with Liquid Crystal Elastomer.

    Science.gov (United States)

    Xing, Huihui; Li, Jun; Shi, Yang; Guo, Jinbao; Wei, Jie

    2016-04-13

    We have developed a novel thermoresponsive photonic actuator based on three-dimensional SiO2 opal photonic crystals (PCs) together with liquid crystal elastomers (LCEs). In the process of fabrication of such a photonic actuator, the LCE precursor is infiltrated into the SiO2 opal PC followed by UV light-induced photopolymerization, thereby forming the SiO2 opal PC/LCE composite film with a bilayer structure. We find that this bilayer composite film simultaneously exhibits actuation behavior as well as the photonic band gap (PBG) response to external temperature variation. When the SiO2 opal PC/LCE composite film is heated, it exhibits a considerable bending deformation, and its PBG shifts to a shorter wavelength at the same time. In addition, this actuation is quite fast, reversible, and highly repeatable. The thermoresponsive behavior of the SiO2 opal PC/LCE composite films mainly derives from the thermal-driven change of nematic order of the LCE layer which leads to the asymmetric shrinkage/expansion of the bilayer structure. These results will be of interest in designing optical actuator systems for environment-temperature detection.

  7. The crystal structure and thermal expansion of the perovskite-type Nd0.75Sm0.25GaO3: powder diffraction and lattice dynamical studies

    Science.gov (United States)

    Senyshyn, A.; Oganov, A. R.; Vasylechko, L.; Ehrenberg, H.; Bismayer, U.; Berkowski, M.; Matkovskii, A.

    2004-01-01

    The structure of Nd0.75Sm0.25GaO3 was studied by high-resolution powder diffraction methods using conventional x-ray and synchrotron radiation in the temperature range 85-1173 K. The GdFeO3 structure type was confirmed for Nd0.75Sm0.25GaO3 in the temperature region investigated and no structural transitions were observed. The cell parameters show a monotonic and anisotropic increase with temperature. The interatomic potential was fitted using the GULP code. Using this potential, a self-consistent approximation following the Debye model was constructed from the elastic constants of the crystals. The total phonon DOS, its projections onto atomic species, heat capacity Cv, Grüneisen parameter ggr and thermal expansion coefficient agr were considered in the framework of quasiharmonic lattice dynamics and the Debye model. The shape of the phonon DOS calculated from lattice dynamics differs significantly from the respected Debye DOS. The rare earth, gallium and oxygen atoms dominate in different frequency regions of the phonon spectrum. The heat capacity is well reproduced by the Debye model below 100 K, where acoustic phonons play an important role and above 800 K when the classical limit is reached. Predicted values of Grüneisen parameter and thermal expansion coefficients in the frame of the Debye model are {\\sim } 35% too low. Therefore, the thermal properties of Nd0.75Sm0.25GaO3 cannot be explained by acoustic phonons only and hence, Nd0.75Sm0.25GaO3 cannot be described perfectly as a Debye-like solid with respect to its thermodynamic properties.

  8. The crystal structure and thermal expansion of the perovskite-type Nd{sub 0.75}Sm{sub 0.25}GaO{sub 3}: powder diffraction and lattice dynamical studies

    Energy Technology Data Exchange (ETDEWEB)

    Senyshyn, A [Lviv Polytechnic National University, Bandera Street 12, 79013 Lviv (Ukraine); Oganov, A R [Laboratory of Crystallography, Department of Materials, ETH Zurich, CH-8092 Zurich (Switzerland); Vasylechko, L [Lviv Polytechnic National University, Bandera Street 12, 79013 Lviv (Ukraine); Ehrenberg, H [Darmstadt University of Technology, Institute for Materials Science, Petersenstrasse 23, D-64287 Darmstadt (Germany); Bismayer, U [Mineralogisch-Petrographisches Institut, Universitat Hamburg, Grindelallee 48, D-20146 Hamburg (Germany); Berkowski, M [Institute of Physics Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Matkovskii, A [Lviv Polytechnic National University, Bandera Street 12, 79013 Lviv (Ukraine)

    2004-01-28

    The structure of Nd{sub 0.75}Sm{sub 0.25}GaO{sub 3} was studied by high-resolution powder diffraction methods using conventional x-ray and synchrotron radiation in the temperature range 85 - 1173 K. The GdFeO{sub 3} structure type was confirmed for Nd{sub 0.75}Sm{sub 0.25}GaO{sub 3} in the temperature region investigated and no structural transitions were observed. The cell parameters show a monotonic and anisotropic increase with temperature. The interatomic potential was fitted using the GULP code. Using this potential, a self-consistent approximation following the Debye model was constructed from the elastic constants of the crystals. The total phonon DOS, its projections onto atomic species, heat capacity C{sub v}, Grueneisen parameter {gamma} and thermal expansion coefficient {alpha} were considered in the framework of quasiharmonic lattice dynamics and the Debye model. The shape of the phonon DOS calculated from lattice dynamics differs significantly from the respected Debye DOS. The rare earth, gallium and oxygen atoms dominate in different frequency regions of the phonon spectrum. The heat capacity is well reproduced by the Debye model below 100 K, where acoustic phonons play an important role and above 800 K when the classical limit is reached. Predicted values of Grueneisen parameter and thermal expansion coefficients in the frame of the Debye model are {approx} 35% too low. Therefore, the thermal properties of Nd{sub 0.75}Sm{sub 0.25}GaO{sub 3} cannot be explained by acoustic phonons only and hence, Nd{sub 0.75}Sm{sub 0.25}GaO{sub 3} cannot be described perfectly as a Debye-like solid with respect to its thermodynamic properties.

  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. THE CRYSTAL STRUCTURE OF ALPHA-DIMETHYLTELLURIUM DICHLORIDE,

    Science.gov (United States)

    TELLURIUM COMPOUNDS, *ORGANOMETALLIC COMPOUNDS, CRYSTAL STRUCTURE , CRYSTAL STRUCTURE , CHLORIDES, SYMMETRY(CRYSTALLOGRAPHY), MOLECULAR STRUCTURE, CHEMICAL BONDS, X RAY DIFFRACTION, ANISOTROPY, FOURIER ANALYSIS.

  11. Crystal Structure of Isoquinoline Derivatives

    Institute of Scientific and Technical Information of China (English)

    LUO Mei; ZHANG Jia-Hai; ZHOU Shi-Ming; SUN Jie; YIN Hao; HU Ke-Liang

    2011-01-01

    The chiral compound 5H-imidazol[2,3-b]isoquinoline-l-ethanol-5-one-1,2, 3, 10b-tetrahydro- β(S)-phenyl-3(S)-phenyl was synthesized from the direct condensation of 2- cyanophenyacetonitrile with optically active (S)-(+)-2-phenylglycinol in chlorobenzene under dry, anaerobic conditions. ZnCl2 was used as a Lewis acid catalyst in this reaction, and the structure of this compound was determined by X-ray diffraction, NMR, MS and IR. Crystal data of the title compound: C25H22N2O2, Mr = 382.45, P 21 21 21, a = 5.341(5), b = 16.735(5), c = 22.129(5) A, γ = 90°, V = 1978(2)A^3, Z = 4, Dc = 1.284 g/cm^3, the final R = 0.0321 for 2269 observed reflections with I 〉 2 σ(I) and Rw = 0.0771 for all data.

  12. Crystal structure of 2-pentyloxybenzamide

    Directory of Open Access Journals (Sweden)

    Bernhard Bugenhagen

    2014-10-01

    Full Text Available In the title molecule, C12H17NO2, the amide NH2 group is oriented toward the pentyloxy substituent and an intramolecular N—H...O hydrogen bond is formed with the pentyloxy O atom. The benzene ring forms dihedral angles of 2.93 (2 and 5.60 (2° with the amide group and the pentyloxy group mean planes, respectively. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers with their molecular planes parallel, but at an offset of 0.45 (1 Å to each other. These dimers are ordered into two types of symmetry-related columns extended along the a axis, with the mean plane of one set of dimers in a column approximately parallel to (121 and the other in a column approximately parallel to (1-21. The two planes form a dihedral angle of 85.31 (2°, and are linked via C—H...O hydrogen bonds and C—H...π interactions, forming a three-dimensional framework structure.

  13. Thermal analysis of line-defect photonic crystal lasers

    DEFF Research Database (Denmark)

    Xue, Weiqi; Ottaviano, Luisa; Chen, Yaohui

    2015-01-01

    We report a systematic study of thermal effects in photonic crystal membrane lasers based on line-defect cavities. Two material platforms, InGaAsP and InP, are investigated experimentally and numerically. Lasers with quantum dot layers embedded in an InP membrane exhibit lasing at room temperatur...

  14. Scattering of thermal phonons by extended defects in dielectric crystals

    Energy Technology Data Exchange (ETDEWEB)

    Roth, E. P.

    1975-01-01

    The scattering of thermal phonons by extended defects in dielectric crystals has been observed through measurements of thermal conductivity and ballistic heat pulse propagation. The thermal conductivities of LiF and NaCl conatining 500 low-angle grain boundaries per cm were measured in the range 0.08-5 K. The measurements gave little or no evidence for phonon scattering from the grain boundaries. Measurements of phonon scattering at a 10 deg. grain boundary in silicon using direct generation and detection of ballistically propagating heat pulses were made over an effective phonon temperature range of 2 to 20 K. The grain boundary reflection coefficient was determined to be < 2%. The thermal conductivities of LiF crystals containing 5 x 10/sup 6/ - 3 x 10/sup 7/ dislocations per square cm were measured over the temperature range 0.1 to 10 K. The measurements of the sheared crystal indicated that the slow transverse phonon mode was strongly scattered by a dynamic phonon-dislocation interaction at T approximately < 2 K, while the remaining modes were scattered primarily by the boundaries. The measurements of the bent crystals indicated that, for T approximately < 2 K, the slow transverse and possibly the longitudinal phonons were strongly scattered by a dynamic phonon-dislocation interaction. For T approximately > 2 k, some fraction of the phonons (at least the slow transverse mode) were still strongly scattered, even after long exposure to ..gamma.. irradiation, while the remaining phonons were scattered primarily by the boundaries.

  15. Method of fabricating patterned crystal structures

    KAUST Repository

    Yu, Liyang

    2016-12-15

    A method of manufacturing a patterned crystal structure for includes depositing an amorphous material. The amorphous material is modified such that a first portion of the amorphous thin-film layer has a first height/volume and a second portion of the amorphous thin-film layer has a second height/volume greater than the first portion. The amorphous material is annealed to induce crystallization, wherein crystallization is induced in the second portion first due to the greater height/volume of the second portion relative to the first portion to form patterned crystal structures.

  16. Synthesis, Crystal Structure and Thermal Stability Study of [Cu2(bpe)X2]n (bpe=1,2-trans-bi(4-pyridyl)ethene, X=Cl, Br, I)

    Institute of Scientific and Technical Information of China (English)

    CHEN San-Ping; FAN Guang; GAO Sheng-Li

    2008-01-01

    A series of copper(Ⅰ) halide complexes bridged by bpe (bpe=1,2-trans-bi(4-pyridyl)ethene), [Cu2(bpe)Cl2]n (1),[Cu2(bpe)Br2]n (2) and [Cu2(bpe)I2]n (3) were successfully synthesized and complex 1 has been structurally characterizod by a single crystal X-ray diffraction method.Crystal data for 1 are monoclinic, space group P2(1)/c, a=0.3788(8) nm, b=1.5059(3) nm, c=1.0875(2) nm, β=96.262(4)°, V=0.6165(2) nm3, Z=2, S=1.002, final R indices [I>2σ(I)] R1=0.0288, wR2=0.0579, R index (all data) R1=0.0509, wR2=0.0615.Elemental analyses and IR spectra reveal that the complexes are of isomorphic compounds.In addition, thermogravimetric analyses were also applied to research of the thermal stability of the title complexes.

  17. Thermal Effect in KTP Crystals During High Power Laser Operation

    Institute of Scientific and Technical Information of China (English)

    YAO Jian-Quan; YU Yi-Zhong; CHEN Jin; ZHANG Fan; WANG Peng; WANG Tao; ZHANG Bai-Gang

    2001-01-01

    We report on the theoretical and experimental studies of the thermal effect of the KTP crystal during high power operation. From the dependence of the refractive index temperature coefficients on wavelength, the dependence of the optimum phase-matching angles on temperature is derived. In the experiment, the angle of the frequency-doubled KTP crystal is tilted to compensate for the thermal effect and to obtain △φ = 0.7° when the green laser output power is 30 W and the KTP crystal temperature is about 80°C. We obtained the highest stable output power greater than 40 W with an L-shaped flat-flat intracavity frequency-doubled Nd:YAG laser. The experimental results are very consistent with the theoretical analysis.

  18. Measurements of Thermal Conductivity and Thermal Diffusivity of Hen Egg-White Lysozyme Crystals and Its Solution Using the Transient Short Hot Wire Method

    Science.gov (United States)

    Fujiwara, Seiji; Maki, Syou; Maekawa, Ryunosuke; Tanaka, Seiichi; Hagiwara, Masayuki

    2017-08-01

    Protein crystals are an essentially important biological sample to advance the analysis of X-ray structure, but their thermophysical properties, especially thermal conductivity and thermal diffusivity, have not been studied sufficiently. This current situation can be attributed to various kinds of technical problems; e.g., the fragility of protein crystals and the difficulty of nucleation control. Ideally speaking, protein crystallization should be carried out under a " containerless condition" to eliminate any mechanical distortion of the crystals from the walls. To realize the condition, we have developed an original crystallization method by means of the magneto-Archimedes effect. In this paper, a transient short hot wire method was combined with the technique of magneto-Archimedes effect to realize simultaneous measurement of thermal conductivity and thermal diffusivity of hen egg-white lysozyme (HEWL) crystals. As the results, thermal conductivity and thermal diffusivity of HEWL crystals were found to be 0.410-0.438 \\hbox {W}\\cdot \\hbox {m}^{-1}\\cdot \\hbox {K}^{-1} and 3.77-5.18× 10^{-8} \\hbox {m}2\\cdot \\hbox {s}^{-1}, respectively. We clarified by the crystallizing process of HEWL that the crystals were magnetically levitated at the air-liquid interface and the short hot wire was completely buried into them as the crystals grew. We also measured the HEWL solution by the same methods. The thermal conductivity of the solution had almost the same value as that of water and had little dependency on the concentration of HEWL, but the thermal diffusivity was unclear.

  19. Direct Synthesis, Crystal Structures and Thermal Analyses of the Two-Dimensional Cu(ntp)2(H2O)4 Crystal (ntp=2-nitroterephthalate)%二维网状Cu(ntp)2(H2O)4晶体的直接合成、晶体结构和热分解机理研究

    Institute of Scientific and Technical Information of China (English)

    郭金玉; 张同来; 张建国; 刘艳红; 郁开北

    2006-01-01

    用直接法合成了配合物Cu(ntp)2(H2O)4,并测定了其晶体结构.分子式为C16H16CuN2O16.晶体属单斜晶系,C2/c空间群,晶胞参数为a=2.2665(7)nm,b=0.7068(2)nm,c=1.5755(4)nm,β=126.42(1)°.对晶体进行了DSC和TG-DTG热分析,根据结果提出了可能的热分解过程.%The Cu(ntp)2(H2O)4 coordination compound has been synthesized by direct method and its crystal has been cultured and characterized by X-ray single crystal structural analysis. The crystal is formulated as C16H16CuN2O16 and crystallized in monoclinic system, space group C2/c, with a=2.266 5(7) nm, b =0.706 8(2) nm,thermal decomposition mechanism of Cu(ntp)2(H2O)4 is predicted that it loses its four coordinated water molecules followed by a large weight loss and formation of copper oxide on heating. CCDC: 271680.

  20. Synthesis, crystal structure, crystal growth and physical properties of N,N-diethyl anilinium picrate

    Science.gov (United States)

    Subramaniyan @ Raja, R.; Anandha Babu, G.; Ramasamy, P.

    2011-11-01

    Crystalline substance of N,N-diethyl anilinium picrate (NNDEAP) has been synthesized and single crystals of NNDEAP were successfully grown for the first time by the slow evaporation solution growth technique at room temperature with dimensions 14×10×10 mm3. The formation of the new crystal has been confirmed by single crystal X-ray diffraction studies. The structural perfection of the grown crystal was analyzed by high resolution X-ray diffraction (HRXRD) measurements. The functional groups of NNDEAP have been identified by Fourier transform infrared spectral studies. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) have also been carried out and the thermal behavior of NNDEAP has been studied. The UV-vis-NIR studies have been carried out to identify the optical transmittance and the cut off wavelength of NNDEAP is identified. The dielectric loss and the dielectric constant as a function of frequency and temperature were measured for the grown crystal and the nature of variation of dielectric constant εr and dielectric losses (tan δ) were studied. Vicker's hardness test has been carried out on NNDEAP to measure the load dependent hardness. The laser induced surface damage threshold for the grown crystal was measured using Nd:YAG laser.

  1. Thermal Shock Behavior of Single Crystal Oxide Refractive Concentrators for High Temperatures Solar Thermal Propulsion

    Science.gov (United States)

    Zhu, Dongming; Choi, Sung R.; Jacobson, Nathan S.; Miller, Robert A.

    1999-01-01

    Single crystal oxides such as yttria-stabilized zirconia (Y2O3-ZrO2), yttrium-aluminum-garnet (Y3Al5O12, or YAG), magnesium oxide (MgO) and sapphire (Al2O3) have been considered as refractive secondary concentrator materials for high temperature solar propulsion applications. However, thermal mechanical reliability of the oxide components in severe thermal environments during space mission sun/shade transitions is of great concern. In this paper, critical mechanical properties of these oxide crystals are determined by the indentation technique. Thermal shock resistance of the oxides is evaluated using a high power CO, laser under high temperature-high thermal gradients. Thermal stress fracture behavior and failure mechanisms of these oxide materials are investigated under various temperature and heating conditions.

  2. Growth of N-Glycyl-L-Valine (GV) single crystal and its spectral, thermal and optical characterization

    Science.gov (United States)

    Janarthanan, S.; Sugaraj Samuel, R.; Rajan, Y. C.; Suresh, P.; Thangaraj, K.

    2013-03-01

    A nonlinear optical crystal of N-Glycyl-L-Valine (GV) single crystals was grown by slow evaporation solution growth technique from an aqueous solution. The unit cell parameters and the crystal structure were determined by single crystal X-ray diffraction study. The Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectral studies were carried out to identify the functional groups of the grown crystals. The ultraviolet visible near infrared (UV-Vis-NIR) spectrum was recorded to study the optical transparency of the grown crystal. The thermogravimetric (TG) and differential thermal (DTA) analyses revealed the thermal stability of the sample. The presence of second harmonic generation (SHG) for the grown crystal was confirmed by Kurtz-Perry powder technique.

  3. Thermal Transport in Crystals as a Kinetic Theory of Relaxons

    Directory of Open Access Journals (Sweden)

    Andrea Cepellotti

    2016-10-01

    Full Text Available Thermal conductivity in dielectric crystals is the result of the relaxation of lattice vibrations described by the phonon Boltzmann transport equation. Remarkably, an exact microscopic definition of the heat carriers and their relaxation times is still missing: Phonons, typically regarded as the relevant excitations for thermal transport, cannot be identified as the heat carriers when most scattering events conserve momentum and do not dissipate heat flux. This is the case for two-dimensional or layered materials at room temperature, or three-dimensional crystals at cryogenic temperatures. In this work, we show that the eigenvectors of the scattering matrix in the Boltzmann equation define collective phonon excitations, which are termed here “relaxons”. These excitations have well-defined relaxation times, directly related to heat-flux dissipation, and they provide an exact description of thermal transport as a kinetic theory of the relaxon gas. We show why Matthiessen’s rule is violated, and we construct a procedure for obtaining the mean free paths and relaxation times of the relaxons. These considerations are general and would also apply to other semiclassical transport models, such as the electronic Boltzmann equation. For heat transport, they remain relevant even in conventional crystals like silicon, but they are of the utmost importance in the case of two-dimensional materials, where they can revise, by several orders of magnitude, the relevant time and length scales for thermal transport in the hydrodynamic regime.

  4. Thermal Transport in Crystals as a Kinetic Theory of Relaxons

    Science.gov (United States)

    Cepellotti, Andrea; Marzari, Nicola

    2016-10-01

    Thermal conductivity in dielectric crystals is the result of the relaxation of lattice vibrations described by the phonon Boltzmann transport equation. Remarkably, an exact microscopic definition of the heat carriers and their relaxation times is still missing: Phonons, typically regarded as the relevant excitations for thermal transport, cannot be identified as the heat carriers when most scattering events conserve momentum and do not dissipate heat flux. This is the case for two-dimensional or layered materials at room temperature, or three-dimensional crystals at cryogenic temperatures. In this work, we show that the eigenvectors of the scattering matrix in the Boltzmann equation define collective phonon excitations, which are termed here "relaxons". These excitations have well-defined relaxation times, directly related to heat-flux dissipation, and they provide an exact description of thermal transport as a kinetic theory of the relaxon gas. We show why Matthiessen's rule is violated, and we construct a procedure for obtaining the mean free paths and relaxation times of the relaxons. These considerations are general and would also apply to other semiclassical transport models, such as the electronic Boltzmann equation. For heat transport, they remain relevant even in conventional crystals like silicon, but they are of the utmost importance in the case of two-dimensional materials, where they can revise, by several orders of magnitude, the relevant time and length scales for thermal transport in the hydrodynamic regime.

  5. Crystal Structure and Thermal Behavior of Rubidium 3,5-dihydroxy-2,4,6-trinitrophenolate%3,5-二羟基-2,4,6-三硝基苯酚铷的晶体结构和热行为

    Institute of Scientific and Technical Information of China (English)

    陈红艳; 张同来; 乔小晶; 杨利; 张建国; 郁开北

    2006-01-01

    A novel energetic coordination compound, rubidium 3,5-dihydroxy-2,4,6-trinitrophenolate ([Rb(DHTNP)]n),has been synthesized by reaction of trinitrophloroglueinol with Rb2CO3 in aqueous solution. Its crystal structure has been determined. The crystal belongs to monoclinic system with space group C2/c. In the crystal the Rb cation is coordinated to ten oxygen atoms from seven different DHTNP- anions to form an irregular polyhedron.Two independent molecule geometry structures are found for DHTNP- anion in the complex, which differ in benzene ring and their pattern of intramolecular hydrogen bonds. The DHTNP- anion chains are interlaced with rubidium atoms as knots, and a three-dimensional infinite net structure is formed via coordination and hydrogen bonding. The hydrogen bond and cation-anion interactions are the predominant driving forces in the crystal packing. The thermal property of title complex was studied by using DSC and TG-DTG techniques. CCDC: 290623.

  6. Extra phase noise from thermal fluctuations in nonlinear optical crystals

    DEFF Research Database (Denmark)

    César, J. E. S.; Coelho, A.S.; Cassemiro, K.N.

    2009-01-01

    We show theoretically and experimentally that scattered light by thermal phonons inside a second-order nonlinear crystal is the source of additional phase noise observed in optical parametric oscillators. This additional phase noise reduces the quantum correlations and has hitherto hindered the d...... the direct production of multipartite entanglement in a single nonlinear optical system. We cooled the nonlinear crystal and observed a reduction in the extra noise. Our treatment of this noise can be successfully applied to different systems in the literature....

  7. Effect of thermal shield and gas flow on thermal elastic stresses in 300 mm silicon crystal

    Institute of Scientific and Technical Information of China (English)

    GAO Yu; XIAO Qinghua; ZHOU Qigang; DAI Xiaolin; TU Hailing

    2006-01-01

    The thermal elastic stresses induced in 300 mm Si crystal may be great troubles because it can incur the generation of dislocations and undesirable excessive residual stresses.A special thermal modeling tool, CrysVUn, was used for numerical analysis of thermal elastic stresses and stress distribution of 300 mm Si crystal under the consideration of different thermal shields and gas flow conditions.The adopted governing partial equations for stress calculation are Cauchy's first and second laws of motion.It is demonstrated that the presence and shape of thermal shield, the gas pressure and velocity can strongly affect von Mises stress distribution in Si crystal.With steep-wall shield, however, the maximal stress and ratio of high stress area are relatively low.With slope-wall shield or without shield, both maximal stress and ratio of high stress area are increased in evidence.Whether thermal shields are used or not, the increase of gas flow velocity could raise the stress level.In contrast, the increase of gas pressure cannot result in so significant effect.The influence of thermal shield and gas flow should be attributed to the modification of heat conduction and heat radiation by them.

  8. Influence of heat transfer on thermal effects of the endpumped laser crystal

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yin-ke; HE Yan-ping; ZAN Hui-ping; YANG Hao

    2010-01-01

    A thermal model of crystal is established. The temperature field differential equation of the diode-end-pumped laser crystal with circular cross-section and new boundary conditions, in which the convection heat transfer is supposed to exist between laser crystal ends and air, is established. The analytical expressions of temperature field, thermal distortion and additional optical path difference (OPD) of crystal are obtained. By numerical calculation, the influence of heat transfer on the thermal effects of laser crystal Nd:YAG is studied. Results show that crystal's thermal effects, including temperature field, thermal distortion, OPD and thermal focal length, are all weakened as the heat transfer through ends of crystal is strengthened. This conclusion could be used to control thermal effects of laser crystal and improve laser working stability.

  9. synthesis, characterization and crystal structure of a ...

    African Journals Online (AJOL)

    Preferred Customer

    Crystal and molecular structure of the complex ... Coordination chemistry of molybdenum(VI) has attracted considerable attention due to its biochemical significance [1-3] as well as for the efficient catalytic properties in several organic.

  10. Pattern information extraction from crystal structures

    Science.gov (United States)

    Okuyan, Erhan; Güdükbay, Uğur; Gülseren, Oğuz

    2007-04-01

    Determining the crystal structure parameters of a material is an important issue in crystallography and material science. Knowing the crystal structure parameters helps in understanding the physical behavior of material. It can be difficult to obtain crystal parameters for complex structures, particularly those materials that show local symmetry as well as global symmetry. This work provides a tool that extracts crystal parameters such as primitive vectors, basis vectors and space groups from the atomic coordinates of crystal structures. A visualization tool for examining crystals is also provided. Accordingly, this work could help crystallographers, chemists and material scientists to analyze crystal structures efficiently. Program summaryTitle of program: BilKristal Catalogue identifier: ADYU_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADYU_v1_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions: None Programming language used: C, C++, Microsoft .NET Framework 1.1 and OpenGL Libraries Computer: Personal Computers with Windows operating system Operating system: Windows XP Professional RAM: 20-60 MB No. of lines in distributed program, including test data, etc.:899 779 No. of bytes in distributed program, including test date, etc.:9 271 521 Distribution format:tar.gz External routines/libraries: Microsoft .NET Framework 1.1. For visualization tool, graphics card driver should also support OpenGL Nature of problem: Determining crystal structure parameters of a material is a quite important issue in crystallography. Knowing the crystal structure parameters helps to understand physical behavior of material. For complex structures, particularly, for materials which also contain local symmetry as well as global symmetry, obtaining crystal parameters can be quite hard. Solution method: The tool extracts crystal parameters such as primitive vectors, basis vectors and identify the space group from

  11. Thermal and chemical decomposition of di(pyrazine)silver(II) peroxydisulfate and unusual crystal structure of a Ag(I) by-product.

    Science.gov (United States)

    Leszczyński, Piotr J; Budzianowski, Armand; Dobrzycki, Lukasz; Cyrański, Michał K; Derzsi, Mariana; Grochala, Wojciech

    2012-01-14

    High purity samples of a [Ag(pyrazine)(2)]S(2)O(8) complex were obtained using modified synthetic pathways. Di(pyrazine)silver(II) peroxydisulfate is sensitive to moisture forming [Ag(pyrazine)(2)](S(2)O(8))(H(2)O) hydrate which degrades over time yielding HSO(4)(-) derivatives and releasing oxygen. One polymorphic form of pyrazinium hydrogensulfate, β-(pyrazineH(+))(HSO(4)(-)), is found among the products of chemical decomposition together with unique [Ag(i)(pyrazine)](5)(H(2)O)(2)(HSO(4))(2)[H(SO(4))(2)]. Chemical degradation of [Ag(pyrazine)(2)]S(2)O(8) in the presence of trace amounts of moisture can explain the very low yield of wet synthesis (11-15%). Attempts have failed to obtain a mixed valence Ag(II)/Ag(I) pyrazine complex via partial chemical reduction of the [Ag(pyrazine)(2)]S(2)O(8) precursor with a variety of inorganic and organic reducing agents, or via controlled thermal decomposition. Thermal degradation of [Ag(pyrazine)(2)]S(2)O(8) containing occluded water proceeds at T > 90 °C via evolution of O(2); simultaneous release of pyrazine and SO(3) is observed during the next stages of thermal decomposition (120-285 °C), while Ag(2)SO(4) and Ag are obtained upon heating to 400-450 °C.

  12. Syntheses, Crystal Structures and Kinetic Mechanisms of Thermal Decomposition of Rare Earth Complexes with Schiff Base Derived from o-Vanillin and p-Toluidine

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Three complexes, [Pr(NO3)3(HL)2] (1), [Nd(NO3)3(HL)2] (2) and [Er(NO3)3(HL)2] ·0.5H2O (3),were synthesized from the reaction of a Schiff base ligand 2-[ (4-methylphenylimino)methyl ]-6-methoxyphenol (C15 H15 mental analysis, molar conductance, FT-IR, UV-Vis, 1H NMR and thermal analysis shows the title complexes are neutral molecules where the central Ln( Ⅲ ) ion is ten-coordinated in biapical anti-hexahedron prism geometry, with four oxygen atoms of the phenolic hydroxy and methoxy groups in the two bidentate Schiff base ligands and six oxygen atoms provided by the three bidentate NO3- anions. Additionally, the kinetic mechanism of thermal decomposition of complex 3 was determined with a TG-DTG curves by both integral and differential methods. The functions of thermal decomposition reaction mechanism and the equation of kinetic compensation effect were obtained.

  13. Near-Zero Thermal Expansion and High Ultraviolet Transparency in a Borate Crystal of Zn4 B6 O13.

    Science.gov (United States)

    Jiang, Xingxing; Molokeev, Maxim S; Gong, Pifu; Yang, Yi; Wang, Wei; Wang, Shuaihua; Wu, Shaofan; Wang, Yingxia; Huang, Rongjin; Li, Laifeng; Wu, Yicheng; Xing, Xianran; Lin, Zheshuai

    2016-09-01

    Intrinsic isotropic near-zero thermal expansion is discovered in borate crystal Zn4 B6 O13 with high transparency in the ultraviolet region. First-principles calculations demonstrate that the very low thermal expansion originates mainly from the invariability of the solid [B24 O48 ] truncated octahedra that are fixed by the [Zn4 O13 ] clusters in the ZBO structure.

  14. Experimental thermal mechanics of deployable boom structures

    Science.gov (United States)

    Predmore, R.

    1972-01-01

    An apparatus was developed for thermal distortion measurements on deployable boom structures. The calibration procedure and thermal static bending plus twist measurements are considered. The thermal mechanics test facility is described. A table is presented for several examples of spacecraft applications of thermal static distortion measurements on 3-m deployable booms.

  15. Photonic-crystal fibre: Mapping the structure

    DEFF Research Database (Denmark)

    Markos, Christos

    2015-01-01

    The demonstration of real-time and non-destructive Doppler-assisted tomography of the internal structure of photonic-crystal fibres could aid the fabrication of high-quality fibres with enhanced performance.......The demonstration of real-time and non-destructive Doppler-assisted tomography of the internal structure of photonic-crystal fibres could aid the fabrication of high-quality fibres with enhanced performance....

  16. Crystal structure of meteoritic schreibersites: determination of absolute structure

    Science.gov (United States)

    Skála, Roman; Císařová, Ivana

    Minerals of the schreibersite nickelphosphide series (Fe,Ni)3P crystallize in the non-centrosymmetric space group Ibar 4. As a consequence, they can possess two different spatial arrangements of the constituting atoms within the unit cell, related by the inversion symmetry operation. Here, we present the crystal structure refinements from single crystal X-ray diffraction data for schreibersite grains from iron meteorites Acuña, Carlton, Hex River Mts. (three different crystals), Odessa (two different crystals), Sikhote Alin, and Toluca aiming for the determination of the absolute structure of the examined crystals. The crystals studied cover the composition range from 58 mol% to 80 mol% Fe3P end-member. Unit-cell parameter a and volume of the unit cell V, as well as certain topological structural parameters tightly correlate with Fe3P content. Unit-cell parameter c, on the other hand, does not show such strong correlation. Eight of the nine crystal structure refinements allowed unambiguous absolute structure assignment. The single crystal extracted from Toluca is, however, of poor quality and consequently the structure refinement did not provide as good results as the rest of the materials. Also, this crystal has only weak inversion distinguishing power to provide unequivocal absolute structure determination. Six of the eight unambiguous absolute structure determinations indicated inverted atomic arrangement compared to that reported in earlier structure refinements (here called standard). Only two grains, one taken from Odessa iron and the other from the Hex River Mts. meteorite, reveal the dominance of standard crystal structure setting.

  17. Thermal modeling of laser-addressed liquid-crystal displays

    Science.gov (United States)

    Evans, K. E.; Nkansah, M. A.

    1990-06-01

    Optical-absorption calculations and finite-element methods are used to calculate time-dependent temperature profiles in two contrasting laser-addressed liquid-crystal displays. It is shown that the presence of conducting electrode layers has a significant effect on the temperature profiles both by affecting the optical-absorption characteristics of the cell and the resulting thermal conductivity. It is shown that efficient optical absorption does not necessarily result in the best cell-addressing performance.

  18. Extreme low thermal conductivity in nanoscale 3D Si phononic crystal with spherical pores.

    Science.gov (United States)

    Yang, Lina; Yang, Nuo; Li, Baowen

    2014-01-01

    In this work, we propose a nanoscale three-dimensional (3D) Si phononic crystal (PnC) with spherical pores, which can reduce the thermal conductivity of bulk Si by a factor up to 10,000 times at room temperature. Thermal conductivity of Si PnCs depends on the porosity, for example, the thermal conductivity of Si PnCs with porosity 50% is 300 times smaller than that of bulk Si. The phonon participation ratio spectra demonstrate that more phonons are localized as the porosity increases. The thermal conductivity is insensitive to the temperature changes from room temperature to 1100 K. The extreme-low thermal conductivity could lead to a larger value of ZT than unity as the periodic structure affects very little the electric conductivity.

  19. Studies on Growth, Spectral, Thermal, Mechanical and Optical Properties of 4-Bromoanilinium 4-Methylbenzenesulfonate Crystal: A Third Order Nonlinear Optical Material

    OpenAIRE

    Sivakumar,Pillukuruchi Kailasam; Kumar,Saravana; Kumar,Rangasamy Mohan; Kanagadurai,Ramajayam; Sagadevan,Suresh

    2016-01-01

    Abstract 4-Bromoanilinium 4-methylbenzenesulfonate (4BPTS) single crystal was successfully grown from ethanol by slow evaporation method at room temperature. The structure of grown crystal was confirmed by single crystal X-ray diffraction studies. The presence of functional groups of grown crystal was confirmed by the Fourier transform infrared spectroscopy (FTIR) spectral analysis. UV-Visible absorption study was performed on the grown crystal to determine the cut-off wavelength. The thermal...

  20. Structures of cyano-biphenyl liquid crystals

    Science.gov (United States)

    Chu, Yuan-Chao; Tsang, Tung; Rahimzadeh, E.; Yin, L.

    1989-01-01

    The structures of p-alkyl- p'-cyano- bicyclohexanes, C(n)H(2n+1) (C6H10)(C6H10) CN (n-CCH), and p-alkyl- p'-cyano- biphenyls, C(n)H(2n+1) (C6H4)(C6H4) CN (n-CBP), were studied. It is convenient to use an x ray image intensification device to search for symmetric x ray diffraction patterns. Despite the similarities in molecular structures of these compounds, very different crystal structures were found. For the smectic phase of 2CCH, the structure is close to rhombohedral with threefold symmetry. In contrast, the structure is close to hexagonal close-packed with two molecules per unit cell for 4CCH. Since intermolecular forces may be quite weak for these liquid crystals systems, it appears that crystal structures change considerably when the alkyl chain length is slightly altered. Different structures were also found in the crystalline phase of n-CBP for n = 6 to 9. For n = 7 to 9, the structures are close to monclinic. The structures are reminiscent of the smectic-A liquid crystal structures with the linear molecules slightly tilted away from the c-axis. In contrast, the structure is quite different for n = 6 with the molecules nearly perpendicular to the c-axis.

  1. Thermal, dielectric and photoconductivity studies on pure, Mg{sup 2+} and Zn{sup 2+} doped BTCC single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Selvakumar, S. [Department of Physics, Loyola College, Chennai 600034 (India); Rajasekar, S.A. [Department of Physics, Magna College of Engineering, Chennai 600055 (India); Thamizharasan, K. [Department of Physics, Sir Theagaraya College, Chennai 600021 (India); Sivanesan, S. [Department of Chemical Engineering, Anna University, Chennai 600025 (India); Ramanand, A. [Department of Physics, Loyola College, Chennai 600034 (India); Sagayaraj, P. [Department of Physics, Loyola College, Chennai 600034 (India)]. E-mail: psagayaraj@hotmail.com

    2005-10-15

    Single crystals of pure and doped bis(thiourea) cadmium chloride (BTCC) belonging to semiorganic nonlinear optical materials are grown by slow evaporation technique. The lattice parameters of the grown crystals are determined by single-crystal XRD. Single crystal XRD studies reveal that the incorporation of metallic dopants has not changed the structure of the parent crystal. The TGA traces of doped BTCC crystals indicate a marginal increase in the thermal stability of the samples. The response of dielectric constant in the frequency region of 500 Hz to 500 kHz has been investigated and the influence of metal substitution on the dielectric behaviour has been reported. Photoconductivity studies of pure and doped BTCC crystals revealed the positive photoconducting nature. Optical absorption studies indicate the low percentage of absorption of doped crystals in the visible region, thereby confirming the enhancement of NLO property.

  2. Nucleation and structural growth of cluster crystals

    CERN Document Server

    Leitold, Christian

    2016-01-01

    We study the nucleation of crystalline cluster phases in the generalized exponential model with exponent n=4. Due to the finite value of this pair potential for zero separation, at high densities the system forms cluster crystals with multiply occupied lattice sites. Here, we investigate the microscopic mechanisms that lead to the formation of cluster crystals from a supercooled liquid in the low-temperature region of the phase diagram. Using molecular dynamics and umbrella sampling, we calculate the free energy as a function of the size of the largest crystalline nucleus in the system, and compare our results with predictions from classical nucleation theory. Employing bond-order parameters based on a Voronoi tessellation to distinguish different crystal structures, we analyze the average composition of crystalline nuclei. We find that even for conditions where a multiply-occupied fcc crystal is the thermodynamically stable phase, the nucleation into bcc cluster crystals is strongly preferred. Furthermore, w...

  3. Crystal structure from one-electron theory

    DEFF Research Database (Denmark)

    Skriver, H. L.

    1985-01-01

    The authors have studied the crystal structure of all the 3d, 4d, and 5d transition metals at zero pressure and temperature by means of the linear muffin-tin orbital method and Andersen's force theorem. They find that, although the structural energy differences seem to be overestimated by the the......The authors have studied the crystal structure of all the 3d, 4d, and 5d transition metals at zero pressure and temperature by means of the linear muffin-tin orbital method and Andersen's force theorem. They find that, although the structural energy differences seem to be overestimated...... by the theory, the predicted crystal structures are in accord with experiment in all cases except 79Au. In addition, they have investigated the effect of pressure upon the alkali metals (3Li, 11Na, 37Rb, 55Cs) and selected lanthanide metals (57La, 58Ce, 71Lu) and actinide metals (90Th, 91Pa). In these cases...

  4. Comment on the paper "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" by P.M. Dinakaran, S. Kalainathan [Spectrochim. Acta A 111 (2013) 123-130].

    Science.gov (United States)

    Srinivasan, Bikshandarkoil R; Dhuri, Sunder N; Nadkarni, V S

    2014-01-03

    We argue that (trans)-4-chloro-4'-nitrostilbene is not a new organic nonlinear optical material as claimed by Dinakaran and Kalainathan [P.M. Dinakaran, S. Kalainathan, 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, Spectrochim. Acta A 111 (2013) 123-130], but instead a well-known compound whose synthesis, spectral data, single crystal structure and second harmonic generation (SHG) efficiency are well documented in the literature. The title paper is completely erroneous. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Non-isothermal crystallization kinetics and thermal behaviour of PA12/SEBS-g-MA blends

    Indian Academy of Sciences (India)

    Khushboo Rinawa; S N Maiti; R Sonnier; J-M Lopez Cuesta

    2015-09-01

    The thermal behaviour and crystallization kinetics of PA12/SEBS-g-MA blends were investigated under non-isothermal and isothermal conditions using thermogravimetric analysis and differential scanning calorimetry, respectively. The macrokinetic model given by Avrami was used to analyse both the nonisothermal and isothermal crystallization kinetics of the blends. The value of the Avrami exponent during non-isothermal crystallization predicted that pure PA12 and PA12/SEBS-g-MA blends show spherulitic growth with random nucleation of crystal structures as the n-values lie between 3 and 4. The slight nucleating effect of SEBS-g-MA was showed by nucleating activity calculated by the Dobreva and Gutzowa method.

  6. Designing a heterotrinuclear Cu(II)-Ni(II)-Cu(II) complex from a mononuclear Cu(II) Schiff base precursor with dicyanamide as a coligand: synthesis, crystal structure, thermal and photoluminescence properties.

    Science.gov (United States)

    Hopa, Cigdem; Cokay, Ismail

    2016-08-01

    Schiff bases are considered `versatile ligands' in coordination chemistry. The design of polynuclear complexes has become of interest due to their facile preparations and varied synthetic, structural and magnetic properties. The reaction of the `ligand complex' [CuL] {H2L is 2,2'-[propane-1,3-diylbis(nitrilomethanylylidene)]diphenol} with Ni(OAc)2·4H2O (OAc is acetate) in the presence of dicyanamide (dca) leads to the formation of bis(dicyanamido-1κN(1))bis(dimethyl sulfoxide)-2κO,3κO-bis{μ-2,2'-[propane-1,3-diylbis(nitrilomethanylylidene)]diphenolato}-1:2κ(6)O,O':O,N,N',O';1:3κ(6)O,O':O,N,N',O'-dicopper(II)nickel(II), [Cu2Ni(C17H16N2O2)2(C2N3)2(C2H6OS)2]. The complex shows strong absorption bands in the frequency region 2155-2269 cm(-1), which clearly proves the presence of terminal bonding dca groups. A single-crystal X-ray study revealed that two [CuL] units coordinate to an Ni(II) atom through the phenolate O atoms, with double phenolate bridges between Cu(II) and Ni(II) atoms. Two terminal dca groups complete the distorted octahedral geometry around the central Ni(II) atom. According to differential thermal analysis-thermogravimetric analysis (DTA-TGA), the title complex is stable up to 423 K and thermal decomposition starts with the release of two coordinated dimethyl sulfoxide molecules. Free H2L exhibits photoluminescence properties originating from intraligand (π-π*) transitions and fluorescence quenching is observed on complexation of H2L with Cu(II).

  7. 1D polymeric copper(I) complex [Cu2(μ-(2,6-Cl-ba)2en)(μ-I)2]n with exceptionally short Cusbnd Cu distance: Synthesis, characterization, thermal study and crystal structure

    Science.gov (United States)

    Khalaji, Aliakbar Dehno; Peyghoun, Seyyed Javad; Akbari, Alireza; Feizi, Nourollah; Dusek, Michal; Eigner, Vaclav

    2017-01-01

    A new 1D polymeric three coordinated copper(I) complex, [Cu2(μ-(2,6-Cl-ba)2en)(μ-I)2]n, with the bidentate Schiff base ligand N,N‧-bis(2,6-dichlorobenzylidene)ethane-1,2-diamine containing a flexible spacer (dbnd NCH2sbnd CH2sbnd Ndbnd) was synthesized and characterized by elemental analyses, UV-Vis, FT-IR and 1H NMR spectroscopy and thermal analaysis. Its molecular structure was determined by single-crystal X-ray diffraction and shows the (2,6-Cl-ba)2en acts as a bis-monodentate bridging ligand forming the dinuclear [Cu2(μ-(2,6-Cl-ba)2en)] groups. Such dinuclear groups are bridged by two iodine anions [(μ-I)2] to form a 1D polymeric copper(I) complex. The copper(I) ions are coordinated in a distorted trigonal planar geometry by two I atoms and one nitrogen atom of Schiff base ligand (2,6-Cl-ba)2en.

  8. Preparation, crystal structure, thermal decomposition, quantum chemical calculations on [K(ZTO)ṡH2O]∞ and its ligand ZTO

    Science.gov (United States)

    Ma, Cong; Huang, Jie; Ma, Hai-Xia; Xu, Kang-Zhen; Lv, Xing-Qiang; Song, Ji-Rong; Zhao, Ning-Ning; He, Jian-Yun; Zhao, Yi-Sha

    2013-03-01

    A novel potassium complex has been synthesized and characterized under the non-isothermal conditions by DSC and TG-DTG method. The 4,4-azo-1,2,4-triazol-5-one (ZTO) has the molecular formula C4H4N8O2. The thermodynamic parameters, HOMO-LUMO energy gap, total energy and electrostatic potential (MEP) of ZTO are conducted by density functional theory DFT/B3LYP calculation method with 6-311G basis set. In the coordination polymer, with the ligand anion (ZTO-) as space linkers, two types of potassium atoms centers are joined together to form three-dimensional frameworks. The enthalpy, apparent activation energy and pre-exponential factor of the second exothermic decomposition reaction are 85.43 kJ mol-1, 414.4 kJ mol-1and 1037.92 s-1, respectively. The critical temperature of thermal explosion (Tb) for [K(ZTO)ṡH2O]∞ is 275.08 °C. [K(ZTO)ṡH2O]∞ CCDC: 902339.

  9. Five novel lanthanide complexes with 2-chloroquinoline-4-carboxylic acid and 1,10-phenanthroline: Crystal structures, molecular spectra, thermal properties and bacteriostatic activities

    Science.gov (United States)

    Wang, Ye; Jin, Cheng-Wei; He, Shu-Mei; Ren, Ning; Zhang, Jian-Jun

    2016-12-01

    Five novel lanthanide complexes [Ln2(2-ClQL)6(phen)2(H2O)2]·2H2O (Ln = Pr(1), Sm(2), Eu(3), Ho(4), Er(5)); 2-ClQL: 2-chloroquinoline-4-carboxylate; phen: 1,10-phenanthroline; were synthesized by conventional solution method at room temperature and characterized via elemental analysis, powder x-ray diffraction, Infrared spectroscopy and Raman spectrometry. The results indicate that complexes 1-5 are isostructural, and each Ln3+ ion is eight-coordinated adopting a distorted square antiprismatic molecular geometry. Binuclear complex 1 are stitched together via hydrogen bonding interactions to form 1D chains, and further to form 2D sheets by the π-π interactions. Luminescence investigation reveals that complex 3 displays strong red emission. TG/DTG-FTIR, reveal the thermal decomposition processes and products of title complexes. The bacteriostatic activities of the complexes were evaluated against Candida albicans, Escherichia coli, and Staphylococcus aureus.

  10. Comparative analysis of lipid composition and thermal, polymorphic, and crystallization behaviors of granular crystals formed in beef tallow and palm oil.

    Science.gov (United States)

    Meng, Zong; Liu, Yuan-Fa; Jin, Qing-Zhe; Huang, Jian-Hua; Song, Zhi-Hua; Wang, Feng-Yan; Wang, Xing-Guo

    2011-02-23

    Six rectangular block all beef tallow (BT)-based and all palm oil (PO)-based model shortenings prepared on a laboratory scale, respectively denoted BTMS and POMS, were stored under temperature fluctuation cycles of 5-20 °C until granular crystals were observed. The lipid composition and thermal, polymorphic, and isothermal crystallization behaviors of the granular crystals and their surrounding materials separated from BTMS and POMS, respectively, were evaluated. The changes of nanostructure including the aggregation of high-melting triacylglycerols (TAGs) and polymorphic transformation from β' form of double chain length structures to complicated crystal structures, in which the β and β' form crystals of triple and double chain length structures simultaneously coexist, had occurred in granular crystals compared with surrounding materials, whether in BTMS or in POMS. Consequently, a slower crystallization rate appeared in granular crystal parts of both model shortenings noted above, which would yield larger and fewer crystals indicated by the Avrami model analysis that would further aggregate to form large granular crystals.

  11. Structure of crystals of hard colloidal spheres

    Energy Technology Data Exchange (ETDEWEB)

    Pusey, P.N.; van Megen, W.; Bartlett, P.; Ackerson, B.J.; Rarity, J.G.; Underwood, S.M. (Royal Signals and Radar Establishment, Malvern, WR14 3PS, United Kingsom (GB) Department of Applied Physics, Royal Melbourne Institute of Technology, Melbourne, Victoria, Australia School of Chemistry, Bristol University, Bristol, BS8 1TS, United Kingdom Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078)

    1989-12-18

    We report light-scattering measurements of powder diffraction patterns of crystals of essentially hard colloidal spheres. These are consistent with structures formed by stacking close-packed planes of particles in a sequence of permitted lateral positions, {ital A},{ital B},{ital C}, which shows a high degree of randomness. Crystals grown slowly, while still containing many stacking faults, show a tendency towards face-centered-cubic packing: possible explanations for this observation are discussed.

  12. Crystal Structure of Macrocalyxin J

    Institute of Scientific and Technical Information of China (English)

    HE Shan; WU Bin; SHI Hao; SUN Cui-Rong

    2007-01-01

    The title compound, (1α,6β, 1 1β, 14α)-1,7:6,20-diepoxy-6,1 1-dihydroxy- 6,7-secoent- kaur-1 6-ene-7,15-dione-14-acetate (macrocalyxin J), is a diterpenoid which was isolated from the leaves of Rabdosia macrocalyx and characterized by single-crystal X-ray diffraction. It crystallizes in orthorhombic, spac e group P212121 with a = 9.3608(8), b = 14.9787(12), c = 15.5750(13)(A), Z = 4, V = 2183.8(3) (A)3, C22H30O9, Mr = 438.46, Dc = 1.334 g/m3, μ(MoKα) = 0.103 mm-1,F(000) = 936, the final R = 0.0532 and wR = 0.1262 for 2252 observed reflections (I > 2σ(I)). In the molecule, three six-membered rings adopt chair, boat and slightly distorted boat conformations,respectively, while both five-membered rings have approximate envelope conformations.

  13. An analytical description of transient thermal processes in harmonic crystals

    Science.gov (United States)

    Kuzkin, V. A.; Krivtsov, A. M.

    2017-05-01

    We consider two transient thermal processes in uniformly heated harmonic crystals: (i) equalibration of kinetic and potential energies and (ii) redistribution of the kinetic energy among the spatial directions. Equations describing these two processes in two-dimensional and three-dimensional crystals are derived. Analytical solutions of these equations for the square and triangular lattices are obtained. It is shown that the characteristic time of the transient processes is of the order of ten periods of atomic vibrations. The difference between the kinetic and potential energies oscillates in time. For the triangular lattice, amplitude of the oscillations decays inversely proportional to time, while for the square lattice it decays inversely proportional to the square root of time. In general, there is no equipartition of the kinetic energy among spatial directions, i.e. the kinetic temperature demonstrates tensor properties. In addition, the covariance of velocities of different particles is nonzero even at the steady state. The analytical results are supported by numerical simulations. It is also shown that the obtained solutions accurately describe the transient thermal processes in weakly nonlinear crystals at short times.

  14. Crystal structure of levomepromazine maleate

    Directory of Open Access Journals (Sweden)

    Gyula Tamás Gál

    2016-05-01

    Full Text Available The asymmetric unit of the title salt, C19H25N2OS+·C4H3O4− [systematic name: (S-3-(2-methoxyphenothiazin-10-yl-N,N,2-trimethylpropanaminium hydrogen maleate], comprises two (S-levomepromazine cations and two hydrogen maleate anions. The conformations of the two cations are similar. The major difference relates to the orientation of the methoxy substituent at the phenothiazine ring system. The crystal components form a three-dimensional supramolecular network via N—H...O, C—H...O and C—H...π interactions. A comparison of the conformations of the levomepromazine cations with those of the neutral molecule and similar protonated molecules reveals significant conformational flexibility of the phenothiazine ring system and the substituent at the phenothiazine N atom.

  15. Crystal structure of 3-(hydroxymethylchromone

    Directory of Open Access Journals (Sweden)

    Yoshinobu Ishikawa

    2015-07-01

    Full Text Available In the title compound, C10H8O3 (systematic name 3-hydroxymethyl-4H-chromen-4-one, the fused-ring system is slightly puckered [dihedral angle between the rings = 3.84 (11°]. The hydroxy O atom deviates from the heterocyclic ring by 1.422 (1 Å. In the crystal, inversion dimers linked by pairs of O—H...O hydrogen bonds generate R22(12 loops. The dimers are linked by aromatic π–π stacking [shortest centroid–centroid distance = 3.580 (3 Å], and C—H...O hydrogen bonds, generating a three-dimensional network.

  16. Crystal structure of 9-methacryloylanthracene

    Directory of Open Access Journals (Sweden)

    Aditya Agrahari

    2015-04-01

    Full Text Available In the title compound, C18H14O, with systematic name 1-(anthracen-9-yl-2-methylprop-2-en-1-one, the ketonic C atom lies 0.2030 (16 Å out of the anthryl-ring-system plane. The dihedral angle between the planes of the anthryl and methacryloyl moieties is 88.30 (3° and the stereochemistry about the Csp2—Csp2 bond in the side chain is transoid. In the crystal, the end rings of the anthryl units in adjacent molecules associate in parallel–planar orientations [shortest centroid–centroid distance = 3.6320 (7 Å]. A weak hydrogen bond is observed between an aromatic H atom and the O atom of a molecule displaced by translation in the a-axis direction, forming sheets of parallel-planar anthryl groups packing in this direction.

  17. The growth and thermal, electrical properties characterization of Ba2TiSi2O8 piezoelectric crystal

    Science.gov (United States)

    Cao, Shuoliang; Jiang, Bohan; Zheng, Yanqing; Tu, Xiaoniu; Xiong, Kainan; Gao, Pan; Shi, Erwei

    2016-10-01

    Ba2TiSi2O8 (BTS) crystals were successfully grown by the Czochralski method. The raw material ratio was optimized according to the effective segregation coefficient keff of different components in the BTS crystal. The thermal properties of the BTS crystal were systematically studied at elevated temperature, including thermal expansion, specific heat, thermal diffusivity and thermal conductivity. The variations of the thermal expansion coefficients α 33 and α 11 in the temperature range of 25-185 °C were small, whereas those in the temperature range of 185-1000 °C were 17.14×10-6/°C and 4.73×10-6/°C, respectively. A strong anisotropic characteristic in the thermal expansion ratio is associated with the lamellar structure of the BTS crystal. The thermal conductivity increased slowly as the temperature rises. The piezoelectric strain constant d33 of the BTS crystal was determined to be 4.5 pC/N at room temperature using a quasi-static d33 meter. The electrical resistivity of the BTS crystal was investigated at temperatures up to 900 °C, the resistivity ρr of the BTS Z-cut sample was 2.06×109 Ω cm at 800 °C, which is three orders of magnitude higher than that of a Ca3TaGa3Si2O14 (langasite-type crystal) X-cut sample (7.15×106 Ω cm) at the same temperature. Thermal and electrical properties have shown that BTS crystal is a potential alternative material for the high temperature piezoelectric sensors.

  18. Dielectric and thermal behaviour of holmium tartrate trihydrate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Want, B.; Ahmad, F. [Department of Physics, University of Kashmir, Srinagar (India); Kotru, P.N. [Department of Physics and Electronics, University of Jammu (India)

    2007-08-15

    Measurements on dielectric constant of holmium tartrate trihydrate crystals at frequencies of the applied a.c. in the range 1 kHz to 1 MHz and at temperature in the range 30 C to 330 C are reported. The dielectric constant {epsilon}' increases with temperature at all frequencies, attains a peak near 250 C, and then decreases as the temperature goes beyond 250 C. The anomalous dielectric behaviour at near about 250 C is attributed to be as a result of crystallographic/polymorphic phase transition brought about in the material. The results on the dielectric behaviour of the material are supplemented by results of thermal analysis viz., TG and DTA. Thermogravimetric and differential thermal analytic techniques have been used to study thermal behaviour of the material. It is shown that the material is thermally stable up to 220 C beyond which it decomposes through three stages till the formation of holmium oxide at 1200 C. The non-isothermal kinetic parameters e.g., activation energy and the frequency factor have been evaluated for first two stages of thermal decomposition by using the integral method of Coats and Redfern. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Structure and thermal expansion of liquid bismuth

    Directory of Open Access Journals (Sweden)

    Mudry S.

    2015-12-01

    Full Text Available Experimental structural data for liquid Bi were used for estimation of the main structure parameters as well as the thermal expansion coefficient both in supercooled and superheated temperature ranges. It was shown that the equilibrium melt had a positive thermal expansion coefficient within a temperature range upon melting and a negative one at higher temperatures. The former was related to structure changes upon melting, whereas the latter with topologic disordering upon further heating. It was found that the superheated melt had a negative thermal expansion coefficient. The results obtained from structural data were compared with the thermal expansion coefficient calculated from the data of density for liquid Bi.

  20. Aerogel Modified Structural Thermal Protection System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This program will mature and further develop structural syntactic foam insulated integral Thermal Protection System (TPS) designs and materials as an enabling...

  1. The crystal structure and crystal chemistry of fernandinite and corvusite

    Science.gov (United States)

    Evans, H.T.; Post, J.E.; Ross, D.R.; Nelen, J.A.

    1994-01-01

    Using type material of fernandinite from Minasragra, Peru, and corvusite from the Jack Claim, La Sal Mountains, Utah, the properties and crystal chemistry of these minerals have been determined by Rietveld analysis of the powder X-ray-diffraction patterns. The crystal structure of both species is isotypic with the V2O5 -type layer first found for ??-Ag0.68V2O5; it consists of chains of VO6 octahedra linked by opposite corners (parallel to b) condensed by edge-sharing to form the layer. The vanadium has average valence 4.8, and the resulting layer-charge is balanced by varying amounts of Ca, Na, and K in the interlayer region accompanied by labile water. This study has confirmed the validity of fernandinite as a unique mineral species. It is closely related to corvusite, from which it is distinguished on the basis of the dominant interlayer cation: Ca for fernandinite, Na for curvusite. -Authors

  2. Comparative Analysis of Thermal Behavior, Isothermal Crystallization Kinetics and Polymorphism of Palm Oil Fractions

    Directory of Open Access Journals (Sweden)

    Bing Li

    2013-01-01

    Full Text Available Thermal behavior of palm stearin (PS and palm olein (PO was explored by monitoring peak temperature transitions by differential scanning calorimetry (DSC. The fatty acid composition (FAC, isothermal crystallization kinetics studied by pulsed Nuclear Magnetic Resonance (pNMR and isothermal microstructure were also compared. The results indicated that the fatty acid composition had an important influence on the crystallization process. PS and PO both exhibited more multiple endotherms than exotherms which showed irregular peak shapes. An increasing in cooling rate, generally, was associated with an increase in peak size. Application of the Avaimi equation to isothermal crystallization of PS and PO revealed different nucleation and growth mechanisms based on the Avrami exponents. PS quickly reached the end of crystallization because of more saturated triacylglycerol (TAG. The Avrami index of PS were the same as PO under the same isothermal condition at lower temperatrue, indicating that the crystallization mechanism of the two samples based on super-cooling state were the same. According to the polarized light microscope (PLM images, crystal morphology of PS and PO was different. With the temperature increased, the structure of crystal network of both PS and PO gradually loosened.

  3. Thermally switchable flexible liquid crystal devices in prepolymer-doped cholesteric liquid crystals

    Science.gov (United States)

    Fuh, A. Y.-G.; Li, J.-H.; Cheng, K.-T.

    2010-10-01

    This work describes an approach for fabricating thermally switchable flexible liquid crystal devices in prepolymer-doped cholesteric liquid crystals (CLCs). The roughness of the UV-cured polymer film eliminates the stability of planar CLCs, allowing the textures in the UV-cured regions to be changed from planar to focal conic. Impurities associated with doping with prepolymers cause the clearing temperature of LCs in the UV-cured regions to differ from that in the uncured regions as the prepolymers are polymerized. Therefore, the textures in these two regions can be switched by controlling the temperature. Thermally switchable flexible LC devices, such as optically addressed smart cards, light valves, and others, can be realized using this approach.

  4. Synthesis, Crystal Structure and Thermal Decomposition of [Ce(NO3)5H2O]·(C3N2H5)2%[Ce(NO3)5H2O]·(C3H5N2)2的合成、晶体结构及热分析

    Institute of Scientific and Technical Information of China (English)

    薛岗林; 杨一心; 李恒新; 何水样; 李君

    2001-01-01

    Colorless crystal,[Ce(NO3) 5H2O]·(C3N2H5)2, has been obtained from the reaction of Ce(NO3)3 with imdazole in the aqueous solution and its crystal structure has been determined by single crystal X-ray diffraction techniques. The crystal belongs to triclinic, space group P1. The cell parameters are: a=0.7489(1) nm, b=0.7914(2)nm, c=1.8139(3)nm, α=89.39(2)°, β=89.37(1)°, γ=63.18(2)°, Dc=2. lg·cm-3, Z=2, R=0.0319. In the compound, all of five nitrates are bidentate and one molecule of water is monodentate, the coordination number of Ce(Ⅲ) is 11.The processes of thermal decomposition of the compound was proposed by its TG curve.

  5. Mechanism of the Reduced Thermal Conductivity of Fishbone-Type Si Phononic Crystal Nanostructures

    Science.gov (United States)

    Nomura, M.; Maire, J.

    2015-06-01

    The mechanism of the reduced thermal conductivity of fishbone-type phononic crystal (PnC) nanostructures, in which ballistic phonon transport is dominant, was investigated with consideration of both the wave and particle nature of phonons. Phononic band diagrams were calculated for an Si nanowire and a fishbone-type PnC structure with a period of 100 nm, and a clear reduction of the group velocity of phonons, because of a zone-folding effect, was shown. Air-suspended Si nanowires and fishbone-type PnC structures were fabricated by electron beam (EB) lithography, and their thermal conductivities were measured by use of the originally developed micro time-domain thermoreflectance method. The PnC structure had a much lower thermal conductivity. We measured the thermal conductivity of a variety of PnC structures with different fin widths to investigate the mechanism of the reduced thermal conductivity observed. The result indicates that the increase of the phonon traveling distance. as a result of the fins, also results in reduced thermal conductivity.

  6. Lessons from crystal structures of kainate receptors

    DEFF Research Database (Denmark)

    Møllerud, Stine; Frydenvang, Karla Andrea; Pickering, Darryl S

    2017-01-01

    structure and how they bind agonists, antagonists and ions. The first structure of the ligand-binding domain of the GluK1 subunit was reported in 2005, seven years after publication of the crystal structure of a soluble construct of the ligand-binding domain of the AMPA-type subunit GluA2. Today, a full......-length structure has been determined of GluK2 by cryo electron microscopy to 7.6 Å resolution as well as 84 high-resolution crystal structures of N-terminal domains and ligand-binding domains, including agonist and antagonist bound structures, modulatory ions and mutations. However, there are still many unanswered...

  7. High-frequency thermal processes in harmonic crystals

    CERN Document Server

    Kuzkin, Vitaly A

    2016-01-01

    We consider two high-frequency thermal processes in uniformly heated harmonic crystals relaxing towards equilibrium: (i) equilibration of kinetic and potential energies and (ii) redistribution of energy among spatial directions. Equation describing these processes with deterministic initial conditions is derived. Solution of the equation shows that characteristic time of these processes is of the order of ten periods of atomic vibrations. After that time the system practically reaches the stationary state. It is shown analytically that in harmonic crystals temperature tensor is not isotropic even in the stationary state. As an example, harmonic triangular lattice is considered. Simple formula relating the stationary value of the temperature tensor and initial conditions is derived. The function describing equilibration of kinetic and potential energies is obtained. It is shown that the difference between the energies (Lagrangian) oscillates around zero. Amplitude of these oscillations decays inversely proport...

  8. Crystal structure of putrescine aspartic acid complex

    OpenAIRE

    Ramaswamy, S.; Murthy, MRN

    1990-01-01

    Polyamines, putrescine, spermidine and spermine are ubiquitous biogenic cations believed to be important for a variety of cellular processes. In order to obtain structural information on the interaction of these amines with other biomolecules, the structure of a complex of putrescine with aspartic acid was determined using single crystal X-ray diffraction methods. The crystals belong monoclinic space group $C_2$ with $a = 21.504 \\AA$, $b = 4.779 \\AA$, $c = 8.350 \\AA$ and $\\beta = {97.63}^{\\ci...

  9. Crystal structure of canagliflozin hemihydrate

    Directory of Open Access Journals (Sweden)

    Kai-Hang Liu

    2016-05-01

    Full Text Available There are two canagliflozin molecules (A and B and one water molecule in the asymmetric unit of the title compound, C24H25FO5S·0.5H2O [systematic name: (2S,3R,4R,5S,6R-2-(3-{[5-(4-fluorophenylthiophen-2-yl]methyl}-4-methylphenyl-6-(hydroxymethyl-3,4,5,6-tetrahydro-2H-pyran-3,4,5-triol hemihydrate]. The dihedral angles between the methylbenzene and thiophene rings are 115.7 (4 and 111.7 (4°, while the dihedral angles between the fluorobenzene and thiophene rings are 24.2 (6 and 20.5 (9° in molecules A and B, respectively. The hydropyran ring exhibits a chair conformation in both canagliflozin molecules. In the crystal, the canagliflozin molecules and lattice water molecules are connected via O—H...O hydrogen bonds into a three-dimensional supramolecular architecture.

  10. Crystal structure of canagliflozin hemihydrate.

    Science.gov (United States)

    Liu, Kai-Hang; Gu, Jian-Ming; Hu, Xiu-Rong; Tang, Gu-Ping

    2016-05-01

    There are two canagliflozin mol-ecules (A and B) and one water mol-ecule in the asymmetric unit of the title compound, C24H25FO5S·0.5H2O [systematic name: (2S,3R,4R,5S,6R)-2-(3-{[5-(4-fluoro-phen-yl)thio-phen-2-yl]meth-yl}-4-methylphen-yl)-6-(hy-droxy-meth-yl)-3,4,5,6-tetra-hydro-2H-pyran-3,4,5-triol hemihydrate]. The dihedral angles between the methyl-benzene and thio-phene rings are 115.7 (4) and 111.7 (4)°, while the dihedral angles between the fluoro-benzene and thio-phene rings are 24.2 (6) and 20.5 (9)° in mol-ecules A and B, respectively. The hydro-pyran ring exhibits a chair conformation in both canagliflozin mol-ecules. In the crystal, the canagliflozin mol-ecules and lattice water mol-ecules are connected via O-H⋯O hydrogen bonds into a three-dimensional supra-molecular architecture.

  11. Crystal Structure of 8-Demethoxyrunanine

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Ling

    2008-01-01

    A new hasubanane-type alkaloid, 8-demethoxyrunanine, was isolated from Sino- menium acutum and characterized by melting point, HREIMS, 1H NMR, and X-ray diffraction analysis. X-ray diffraction reveals that the title compound crystallizes in the orthorhombic system, space group P212121 with a = 7.308(1), b = 21.742(5), c = 22.893(4) ?, V = 3637.5(11) ?3, Z = 8, Dx = 1.254 g/cm3, F(000) = 1472, μ(MoKα) = 0.087 mm-1, the final R = 0.0438 and wR = 0.0575 for 4497 independent reflections with Rint = 0.0192 and 2091 observed reflections with I > 2σ(I). Four rings (ring A: one benzene ring, ring B: one hexagon carbon ring in a half-chair conformation, ring C: one hexagon carbon ring with α,β-unsaturated ketone segment (-CR2=CR1-C=O) in a screw-boat conformation, and ring D: one nonplanar tetrahydropyrrole) form a hasubanane-type alkaloid.

  12. A uranium (VI) complex: Synthesis, structural and thermal kinetic analysis

    Science.gov (United States)

    Goel, Nidhi

    2016-08-01

    A new complex [UO2(2,6-DNP)2phen] (1) (2,6-DNP = 2,6-dinitrophenol, phen = 1,10-phenanthroline) was synthesized, and identified by elemental analysis, IR, Powder XRD and single crystal X-ray crystallography. Crystal structure provides the abundant information's about the bonding and geometry around the U(VI) metal center. The thermal decomposition was studied by TG-DSC, and the kinetics of thermolysis was investigated by applying model fitting as well as isoconversional methods. Explosion delay measurement (De) was also evaluated to determine the response of this complex under the condition of rapid heating.

  13. Crystal structure determination of Jatrorrhizine chloride

    Institute of Scientific and Technical Information of China (English)

    LEI XianRong; YANG JianHua; LIN Xiang; DAI Qin; CHENG Qiang; GUO LingHong; LI Hui

    2009-01-01

    Optimum resolution data of powder X-ray diffraction (PXRD) for Jatrorrhizine (Jat) were collected by an X' Pert Pro MPD diffractometer with an X'celerator detector under the stepwise scanning condition as 8.255 ms and 0.00836°per step,2θrange of 50°-80° and total scanning period of 8-10 min. Indexing of the crystal system and a search of the space group from the powder X-ray diffraction data were conducted by the computational crystallography method. The pilot crystal models of Jat were globally optimized with Monte Carlo method and then refined with the Rietveld method. In parallel with PXRD test,single crystals of Jat were cultured in an aqueous solution by a slow-decreasing temperature method,then its crystal structure was determined by single crystal X-ray diffraction (SCXRD). Both crystal structures from PXRD and SCXRD are identical. The results show that the crystal structure of Jat belongs to a monoclinic system and the space group P21/c. The parameters of cell dimensions from PXRD are a=7.69(A),b= 12.55(A),c=20.89(A),β=106.53°,Z=4,and V=1933.4(A)3,meanwhile the parameters from SCXRD are a=7.72(A),b=12.61(A),c=20.99(A),β=106.38°,Z=4,and V=1961.3(A)3.

  14. Thermal conductivity of single crystal and ceramic AlN

    Science.gov (United States)

    AlShaikhi, A.; Srivastava, G. P.

    2008-04-01

    We have applied the Callaway theory and used a detailed account of three-phonon scattering processes to calculate the thermal conductivity of three AlN single crystal samples containing different amounts of oxygen and two AlN ceramic samples with different grain sizes and oxygen contamination levels. The N-drift contribution to the total conductivity has been quantified. The influence on the thermal conductivity of oxygen-related defects, and grain boundaries in ceramic samples, has been investigated. The theoretical results obtained from this work are in good agreement with available experimental data. Our calculations suggest that the "effective" boundary length is greater than the reported grain size for each of the two ceramic samples studied by Watari et al. [J. Mater. Res. 17, 2940 (2002)].

  15. Thermally induced atmospheric pressure gas discharges using pyroelectric crystals

    Science.gov (United States)

    Johnson, Michael J.; Linczer, John; Go, David B.

    2014-12-01

    Using a heated pyroelectric crystal, an atmospheric pressure gas discharge was generated through the input of heat. When put through a change in temperature, the polarization of a pyroelectric can change significantly, creating a substantial electric potential at its surface. When configured with a grounded sharp counter electrode, a large inhomogeneous electric field forms in the interstitial gas to initiate a corona-like discharge. Under constant heating conditions, gaseous ions drifting to the pyroelectric accumulate and screen the electric field, extinguishing the discharge. By thermally cycling the pyroelectric, negative and positive discharges are generated during heating and cooling, respectively, with peak currents on the order of 80 nA. Time-integrated visualization confirmed the generation of both a corona-like discharge and a surface discharge on the pyroelectric. Parametric studies identified that thermal cycling conditions significantly influence discharge formation for this new atmospheric pressure discharge approach.

  16. Crystal structure of the eukaryotic ribosome.

    Science.gov (United States)

    Ben-Shem, Adam; Jenner, Lasse; Yusupova, Gulnara; Yusupov, Marat

    2010-11-26

    Crystal structures of prokaryotic ribosomes have described in detail the universally conserved core of the translation mechanism. However, many facets of the translation process in eukaryotes are not shared with prokaryotes. The crystal structure of the yeast 80S ribosome determined at 4.15 angstrom resolution reveals the higher complexity of eukaryotic ribosomes, which are 40% larger than their bacterial counterparts. Our model shows how eukaryote-specific elements considerably expand the network of interactions within the ribosome and provides insights into eukaryote-specific features of protein synthesis. Our crystals capture the ribosome in the ratcheted state, which is essential for translocation of mRNA and transfer RNA (tRNA), and in which the small ribosomal subunit has rotated with respect to the large subunit. We describe the conformational changes in both ribosomal subunits that are involved in ratcheting and their implications in coordination between the two associated subunits and in mRNA and tRNA translocation.

  17. Modular crystals as modulated structures

    DEFF Research Database (Denmark)

    Elcoro, L.; Perez-Mato, J.M.; Friese, K.;

    2008-01-01

    The use of the superspace formalism is extended to the description and refinement of the homologous series of modular structures with two symmetry-related modules with different orientations. The lillianite homologous series has been taken as a study case. Starting from a commensurate modulated c...

  18. Comparison of High Temperature Crystal Lattice and Bulk Thermal Expansion Measurements of LGT Single Crystal

    Energy Technology Data Exchange (ETDEWEB)

    Beaucage, Timothy R [University of Maine; Beenfeldt, Eric P [University of Maine; Speakman, Scott A [ORNL; Porter, Wallace D [ORNL; Payzant, E Andrew [ORNL; Pereira da Cunha, Mauricio [University of Maine

    2006-01-01

    Among the langasite family of crystals (LGX), the three most popular materials are langasite (LGS, La3Ga5SiO14), langatate (LGT, La3Ga5.5Ta0.5O14) and langanite (LGN, La3Ga5.5Nb0.5O14). The LGX crystals have received significant attention for acoustic wave (AW) device applications due to several properties, which include: (1) piezoelectric constants about two and a half times those of quartz, thus allowing the design of larger bandwidth filters; (2) existence of temperature compensated orientations; (3) high density, with potential for reduced vibration and acceleration sensitivity; and (4) possibility of operation at high temperatures, since the LGX crystals do not present phase changes up to their melting point above 1400degC. The LGX crystals' capability to operate at elevated temperatures calls for an investigation on the growth quality and the consistency of these materials' properties at high temperature. One of the fundamental crystal properties is the thermal expansion coefficients in the entire temperature range where the material is operational. This work focuses on the measurement of the LGT thermal expansion coefficients from room temperature (25degC) to 1200degC. Two methods of extracting the thermal expansion coefficients have been used and compared: (a) dual push-rod dilatometry, which provides the bulk expansion; and (b) x-ray powder diffraction, which provides the lattice expansion. Both methods were performed over the entire temperature range and considered multiple samples taken from <001> Czochralski grown LGT material. The thermal coefficients of expansion were extracted by approximating each expansion data set to a third order polynomial fit over three temperature ranges reported in this work: 25degC to 400degC, 400degC to 900degC, 900degC to 1200degC. An accuracy of fit better than 35ppm for the bulk expansion and better than 10ppm for the lattice expansion have been obtained with the aforementioned polynomial fitting. The

  19. Shear induced structures in crystallizing cocoa butter

    Science.gov (United States)

    Mazzanti, Gianfranco; Guthrie, Sarah E.; Sirota, Eric B.; Marangoni, Alejandro G.; Idziak, Stefan H. J.

    2004-03-01

    Cocoa butter is the main structural component of chocolate and many cosmetics. It crystallizes in several polymorphs, called phases I to VI. We used Synchrotron X-ray diffraction to study the effect of shear on its crystallization. A previously unreported phase (phase X) was found and a crystallization path through phase IV under shear was observed. Samples were crystallized under shear from the melt in temperature controlled Couette cells, at final crystallization temperatures of 17.5^oC, 20^oC and 22.5^oC in Beamline X10A of NSLS. The formation of phase X was observed at low shear rates (90 s-1) and low crystallization temperature (17.5^oC), but was absent at high shear (720 s-1) and high temperature (20^oC). The d-spacing and melting point suggest that this new phase is a mixture rich on two of the three major components of cocoa butter. We also found that, contrary to previous reports, the transition from phase II to phase V can happen through the intermediate phase IV, at high shear rates and temperature.

  20. Growth, mechanical, dielectric, thermal and optical studies of a nonlinear optical crystal: L-Histidinium dipicrate dihydrate

    Energy Technology Data Exchange (ETDEWEB)

    Helen, F.; Kanchana, G., E-mail: kanchanagac@gmail.com

    2015-02-01

    Nonlinear optical single crystals of L-histidinium dipicrate dihydrate (LHDPDH) were grown by slow evaporation solution growth technique at room temperature. The microstructure and growth features were analysed by chemical etching. The grown crystal was subjected to X-ray diffraction analysis to confirm its purity and crystal structure. Mechanical behaviour of the grown crystal was analysed by Vicker's microhardness test. The stiffness constant was evaluated for various loads. The dielectric behaviour was investigated at different frequencies and temperatures. AC conductivity and activation energy were determined. Electronic properties, such as valence electron plasma energy, average energy gap or Penn gap, Fermi energy and electronic polarizability were calculated. Thermal analysis confirmed the association of two water molecules in the crystal lattice of LHDPDH and revealed the thermal stability of the crystal. Photoconductivity study reveals that LHDPDH exhibits positive photoconductivity. The optical transmission window and optical band gap of the crystal were found by UV–vis–NIR studies. Second harmonic generation efficiency was found to be 2.5 times that of the standard KDP crystal. The laser damage threshold for the grown crystal was measured using Nd:YAG laser. - Highlights: • High stiffness constant indicates strong binding forces between ions. • Low dielectric constant and dielectric loss at high frequencies. • LHDPDH crystal shows positive photoconductivity. • The laser damage threshold is found to be higher than urea. • SHG efficiency is 2.5 times that of KDP.

  1. Measurements of thermal conductivity and thermal diffusivity of hen egg-white lysozyme crystals using a short hot wire method

    Science.gov (United States)

    Fujiwara, Seiji; Maki, Syou; Tanaka, Seiichi; Maekawa, Ryunosuke; Masuda, Tomoki; Hagiwara, Masayuki

    2017-07-01

    Thermal conductivity and thermal diffusivity of hen egg-white lysozyme (HEWL) crystals were examined by using the transient short hot wire method. This method is based on the conventional hot wire method, but improved by using a wire that is much shorter than conventional ones. The magneto-Archimedes levitation technique was utilized to attach the HEWL crystals onto the wire. Owing to the upward magnetic force, the HEWL crystals were deposited at the air-liquid interface of the protein buffer solution where the short hot wire was preliminarily fixed. In situ observation clarified that the wire was completely buried into the HEWL crystals. By means of these techniques, the measurement of thermal conductivity and thermal diffusivity of HEWL crystals was realized for the first time. Gadolinium chloride (a paramagnetic subject) was used as a precipitant agent of crystallization. Crystal growth was carried out over 20 h at 17.2 °C. The applied magnetic field was 4 T. Measurements were conducted during the crystal growth at two different times. The thermal conductivity and diffusivity of the HEWL crystals were determined to be 0.410 W/(m.K) and 3.77×10-8 m2/s at 14 h after, and 0.438 W/(m.K) and 5.18×10-8 m2/s at 20 h after, respectively. We emphasize that this method is versatile and applicable for other protein crystals.

  2. Structure analysis on synthetic emerald crystals

    Science.gov (United States)

    Lee, Pei-Lun; Lee, Jiann-Shing; Huang, Eugene; Liao, Ju-Hsiou

    2013-05-01

    Single crystals of emerald synthesized by means of the flux method were adopted for crystallographic analyses. Emerald crystals with a wide range of Cr3+-doping content up to 3.16 wt% Cr2O3 were examined by X-ray single crystal diffraction refinement method. The crystal structures of the emerald crystals were refined to R 1 (all data) of 0.019-0.024 and w R 2 (all data) of 0.061-0.073. When Cr3+ substitutes for Al3+, the main adjustment takes place in the Al-octahedron and Be-tetrahedron. The effect of substitution of Cr3+ for Al3+ in the beryl structure results in progressively lengthening of the Al-O distance, while the length of the other bonds remains nearly unchanged. The substitution of Cr3+ for Al3+ may have caused the expansion of a axis, while keeping the c axis unchanged in the emerald lattice. As a consequence, the Al-O-Si and Al-O-Be bonding angles are found to decrease, while the angle of Si-O-Be increases as the Al-O distance increases during the Cr replacement.

  3. Single Crystal Structure Determination of Alumina to 1 Mbar

    Science.gov (United States)

    Dong, H.; Zhang, L.; Prakapenka, V.; Mao, H.

    2014-12-01

    Aluminum oxide (Al2O3) is an important ceramic material and a major oxide in the earth. Additionally, alumina is a widely used pressure standard in static high-pressure experiments (Cr3+-bearing corundum, ruby). The changes of its crystal structure with pressure (P) and temperature (T) are important for its applications and understanding its physical properties in the deep Earth. There have been numerous reports on the high P-T polymorphs of alumina. Previous theoretical calculations and experiments suggest that the crystal structure of Al2O3 evolves greatly at high P-T. In this study, we used the newly developed multigrain crystallography method combined with single-crystal x-ray diffraction analysis technique for the structure determination of alumina at high P-T to provide single-crystal structure refinement for high-pressure phases of Al2O3. Alumina powder was mixed with ~10% Pt and Ne was used as both pressure transmitting media and thermal insulating layers during laser-heating. Coarse-grained aggregates of Al2O3 were synthesized in a laser-heated diamond anvil cell. The structure change of Al2O3 was monitored by in situ x-ray diffraction at ~1 Mbar and 2700 K. The results allow us to distinguish the structural differences between the Rh2O3 (II) structure (space group Pbcn) and perovskite structure (space group Pbnm) for the first high-pressure phase of Al2O3. More detailed results will be discussed in the later work.

  4. Troublesome Crystal Structures: Prevention, Detection, and Resolution.

    Science.gov (United States)

    Harlow, Richard L

    1996-01-01

    A large number of incorrect crystal structures is being published today. These structures are proving to be a particular problem to those of us who are interested in comparing structural moieties found in the databases in order to develop structure-property relationships. Problems can reside in the input data, e.g., wrong unit cell or low quality intensity data, or in the structural model, e.g., wrong space group or atom types. Many of the common mistakes are, however, relatively easy to detect and thus should be preventable; at the very least, suspicious structures can be flagged, if not by the authors then by the referees and, ultimately, the crystallographic databases. This article describes some of the more common mistakes and their effects on the resulting structures, lists a series of tests that can be used to detect incorrect structures, and makes a strong plea for the publication of higher quality structures.

  5. Determining crystal structures through crowdsourcing and coursework

    OpenAIRE

    2016-01-01

    We show here that computer game players can build high-quality crystal structures. Introduction of a new feature into the computer game Foldit allows players to build and real-space refine structures into electron density maps. To assess the usefulness of this feature, we held a crystallographic model-building competition between trained crystallographers, undergraduate students, Foldit players and automatic model-building algorithms. After removal of disordered residues, a team of Foldit pla...

  6. Determining crystal structures through crowdsourcing and coursework

    OpenAIRE

    Horowitz, Scott; Koepnick, Brian; Jain, Neha; Pikkanen, Petri; Shehzad, Raafay; Viosca, Randy; James Fraser, Robert; Leduc, Robert; Madala, Roman; Shnider, Scott; de Boisblanc, Sharon; Butkovich, Slava; Bliven, Spencer; Koldewey, Philipp; Hettler, Stephen

    2016-01-01

    We show here that computer game players can build high-quality crystal structures. Introduction of a new feature into the computer game Foldit allows players to build and real-space refine structures into electron density maps. To assess the usefulness of this feature, we held a crystallographic model-building competition between trained crystallographers, undergraduate students, Foldit players and automatic model-building algorithms. After removal of disordered residues, a team of Foldit pla...

  7. Crystal Structure of Human Enterovirus 71

    Energy Technology Data Exchange (ETDEWEB)

    Plevka, Pavel; Perera, Rushika; Cardosa, Jane; Kuhn, Richard J.; Rossmann, Michael G. (Purdue); (Sentinext)

    2013-04-08

    Enterovirus 71 is a picornavirus associated with fatal neurological illness in infants and young children. Here, we report the crystal structure of enterovirus 71 and show that, unlike in other enteroviruses, the 'pocket factor,' a small molecule that stabilizes the virus, is partly exposed on the floor of the 'canyon.' Thus, the structure of antiviral compounds may require a hydrophilic head group designed to interact with residues at the entrance of the pocket.

  8. THE CRYSTAL STRUCTURE OF 2,7-DIACETOXYTRANS-15,16-DIMETHYL-15,16-DIHYDROPYRENE,

    Science.gov (United States)

    AROMATIC COMPOUNDS, CRYSTAL STRUCTURE ), (*POLYCYCLIC COMPOUNDS, CRYSTAL STRUCTURE ), (* CRYSTAL STRUCTURE , POLYCYCLIC COMPOUNDS), ESTERS, MOLECULAR STRUCTURE, CHEMICAL BONDS, X RAY DIFFRACTION, SCINTILLATION COUNTERS, CANADA

  9. Photonic Crystal Laser-Driven Accelerator Structures

    Energy Technology Data Exchange (ETDEWEB)

    Cowan, Benjamin M.

    2007-08-22

    Laser-driven acceleration holds great promise for significantly improving accelerating gradient. However, scaling the conventional process of structure-based acceleration in vacuum down to optical wavelengths requires a substantially different kind of structure. We require an optical waveguide that (1) is constructed out of dielectric materials, (2) has transverse size on the order of a wavelength, and (3) supports a mode with speed-of-light phase velocity in vacuum. Photonic crystals---structures whose electromagnetic properties are spatially periodic---can meet these requirements. We discuss simulated photonic crystal accelerator structures and describe their properties. We begin with a class of two-dimensional structures which serves to illustrate the design considerations and trade-offs involved. We then present a three-dimensional structure, and describe its performance in terms of accelerating gradient and efficiency. We discuss particle beam dynamics in this structure, demonstrating a method for keeping a beam confined to the waveguide. We also discuss material and fabrication considerations. Since accelerating gradient is limited by optical damage to the structure, the damage threshold of the dielectric is a critical parameter. We experimentally measure the damage threshold of silicon for picosecond pulses in the infrared, and determine that our structure is capable of sustaining an accelerating gradient of 300 MV/m at 1550 nm. Finally, we discuss possibilities for manufacturing these structures using common microfabrication techniques.

  10. Synthesis and Crystal Structure of Dehydroandrographolide Dipolycyclophosphate

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The title compound was synthesized and characterized by IR, NMR, H R S I-M S and MS, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal is of orthorhombic system (C4oH52O11P2, Mr= 770.76), space group P21212, with a = 22.562(5), b =29.224(6), c = 7.1953(14) A, V = 4744.2(16) A3, Z = 4, Dc = 1.079 g/cm3, F(000) = 1640 andμ =0.141 mm-1. The final R = 0.0758 and wR = 0.1778 for 2794 observed reflections with I > 2o(I).Intermolecular hydrogen bonds are found between the O atom of carbonyl group and H atoms of olefinic carbon. The absolute configuration of this molecule was confirmed by comparison with that of the original material.

  11. One dimensional coordination polymers: Synthesis, crystal structures and spectroscopic properties

    Science.gov (United States)

    Karaağaç, Dursun; Kürkçüoğlu, Güneş Süheyla; Şenyel, Mustafa; Şahin, Onur

    2016-11-01

    Two new one dimensional (1D) cyanide complexes, namely [M(4-aepy)2(H2O)2][Pt(CN)4], (4-aepy = 4-(2-aminoethyl)pyridine M = Cu(II) (1) or Zn(II) (2)), have been synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, single crystal X-ray diffraction, thermal and elemental analyses techniques. The crystallographic analyses reveal that 1 and 2 are isomorphous and isostructural, and crystallize in the monoclinic system and C2 space group. The Pt(II) ions are coordinated by four cyanide-carbon atoms in the square-planar geometry and the [Pt(CN)4]2- ions act as a counter ion. The M(II) ions display an N4O2 coordination sphere with a distorted octahedral geometry, the nitrogen donors belonging to four molecules of the organic 4-aepy that act as unidentate ligands and two oxygen atoms from aqua ligands. The crystal structures of 1 and 2 are similar each other and linked via intermolecular hydrogen bonding, Pt⋯π interactions to form 3D supramolecular network. Vibration assignments of all the observed bands are given and the spectral features also supported to the crystal structures of the complexes.

  12. Crystal structure of N-(4-hydroxybenzylacetone thiosemicarbazone

    Directory of Open Access Journals (Sweden)

    Saray Argibay-Otero

    2017-09-01

    Full Text Available The structure of the title compound, C11H15N3OS, shows the flexibility due to the methylene group at the thioamide N atom in the side chain, resulting in the molecule being non-planar. The dihedral angle between the plane of the benzene ring and that defined by the atoms of the thiosemicarbazide arm is 79.847 (4°. In the crystal, the donor–acceptor hydrogen-bond character of the –OH group dominates the intermolecular associations, acting as a donor in an O—H...S hydrogen bond, as well as being a double acceptor in a centrosymmetric cyclic bridging N—H...O,O′ interaction [graph set R22(4]. The result is a one-dimensional duplex chain structure, extending along [111]. The usual N—H...S hydrogen-bonding association common in thiosemicarbazone crystal structures is not observed.

  13. Thermal diffusion boron doping of single-crystal natural diamond

    Science.gov (United States)

    Seo, Jung-Hun; Wu, Henry; Mikael, Solomon; Mi, Hongyi; Blanchard, James P.; Venkataramanan, Giri; Zhou, Weidong; Gong, Shaoqin; Morgan, Dane; Ma, Zhenqiang

    2016-05-01

    With the best overall electronic and thermal properties, single crystal diamond (SCD) is the extreme wide bandgap material that is expected to revolutionize power electronics and radio-frequency electronics in the future. However, turning SCD into useful semiconductors requires overcoming doping challenges, as conventional substitutional doping techniques, such as thermal diffusion and ion implantation, are not easily applicable to SCD. Here we report a simple and easily accessible doping strategy demonstrating that electrically activated, substitutional doping in SCD without inducing graphitization transition or lattice damage can be readily realized with thermal diffusion at relatively low temperatures by using heavily doped Si nanomembranes as a unique dopant carrying medium. Atomistic simulations elucidate a vacancy exchange boron doping mechanism that occurs at the bonded interface between Si and diamond. We further demonstrate selectively doped high voltage diodes and half-wave rectifier circuits using such doped SCD. Our new doping strategy has established a reachable path toward using SCDs for future high voltage power conversion systems and for other novel diamond based electronic devices. The novel doping mechanism may find its critical use in other wide bandgap semiconductors.

  14. Crystal structure of low-symmetry rondorfite

    Science.gov (United States)

    Rastsvetaeva, R. K.; Zadov, A. E.; Chukanov, N. V.

    2008-03-01

    The crystal structure of an aluminum-rich variety of the mineral rondorfite with the composition Ca16[Mg2(Si7Al)(O31OH)]Cl4 from the skarns of the Verkhne-Chegemskoe plateau (the Kabardino-Balkarian Republic, the Northern Caucasus Region, Russia) was solved in the triclinic space group with the unit-cell parameters a = 15.100(2) Å, b = 15.110(2) Å, c = 15.092(2) Å, α = 90.06(1)°, β = 90.01(1)°, γ = 89.93(1)°, Z = 4, sp. gr. P1. The structural model consisting of 248 independent atoms was determined by the phase-correction method and refined to R = 3.8% with anisotropic displacement parameters based on all 7156 independent reflections with 7156 F > 3σ( F). The crystal structure is based on pentamers consisting of four Si tetrahedra linked by the central Mg tetrahedron. The structure can formally be refined in the cubic space group ( a = 15.105 Å, sp. gr. Fd overline 3 , seven independent positions) with anisotropic displacement parameters to R = 2.74% based on 579 reflections with F > 3σ( F) without accounting for more than 1000 observed reflections, which are inconsistent with the cubic symmetry of the crystal structure.

  15. Growth, spectral, optical, thermal, crystallization perfection and nonlinear optical studies of novel nonlinear optical crystal—Urea thiosemicarbazone monohydrate

    Science.gov (United States)

    Hanumantharao, Redrothu; Kalainathan, S.; Bhagavannarayana, G.

    2012-06-01

    Single crystals of organic nonlinear material urea thiosemicarbazone monohydrate (UTM) have been grown by slow evaporation method. The grown crystals were characterized by single crystal X-ray diffraction analysis reveals that sample crystallized in triclinic system with noncentrosymmetric space group P1. Powder XRD pattern confirmed that grown crystal posses highly crystalline nature. FTIR spectrum was recorded to identify the presence of functional groups and molecular structure was confirmed by 1H NMR spectrum. Material confirmation of title compound has been performed by using mass spectroscopic analysis. Elemental composition of grown crystal was confirmed by energy-dispersive spectrometry (EDS). To study the crystalline perfection of the grown crystals, high-resolution X-ray diffraction (HR-XRD) study was carried out. Thermogravimetric and differential thermal analyses were employed to understand the thermal and physio-chemical stability of the synthesized compound. UV-Vis-NIR spectrum revealed the transmission properties of the crystal specimen. Relative SHG efficiency is measured by Kurtz and Perry method and found to about 0.89 times that of standard potassium dihydrogen phosphate (KDP) crystals.

  16. The Effect of Thermal Cycling on Crystal-Liquid Separation During Lunar Magma Ocean Differentiation

    Science.gov (United States)

    Mills, Ryan D.

    2013-01-01

    Differentiation of magma oceans likely involves a mixture of fractional and equilibrium crystallization [1]. The existence of: 1) large volumes of anorthosite in the lunar highlands and 2) the incompatible- rich (KREEP) reservoir suggests that fractional crystallization may have dominated during differentiation of the Moon. For this to have occurred, crystal fractionation must have been remarkably efficient. Several authors [e.g. 2, 3] have hypothesized that equilibrium crystallization would have dominated early in differentiation of magma oceans because of crystal entrainment during turbulent convection. However, recent numerical modeling [4] suggests that crystal settling could have occurred throughout the entire solidification history of the lunar magma ocean if crystals were large and crystal fraction was low. These results indicate that the crystal size distribution could have played an important role in differentiation of the lunar magma ocean. Here, I suggest that thermal cycling from tidal heating during lunar magma ocean crystallization caused crystals to coarsen, leading to efficient crystal-liquid separation.

  17. Thermal Properties of Oxides With Magnetoplumbite Structure for Advanced Thermal Barrier Coatings

    Science.gov (United States)

    Bansal, Narottam P.; Zhu, Dongming; Eslamloo-Grami, Maryam

    2007-01-01

    Oxides having magnetoplumbite structure are promising candidate materials for applications as high temperature thermal barrier coatings because of their high thermal stability, high thermal expansion, and low thermal conductivity. In this study, powders of LaMgAl11O19, GdMgAl11O19, SmMgAl11O19, and Gd0.7Yb0.3MgAl11O19 magnetoplumbite oxides were synthesized by citric acid sol-gel method and hot pressed into disk specimens. The thermal expansion coefficients (CTE) of these oxide materials were measured from room temperature to 1500 C. The average CTE value was found to be approx.9.6x10(exp -6)/C. Thermal conductivity of these magnetoplumbite-based oxide materials was also evaluated using steady-state laser heat flux test method. The effects of doping on thermal properties were also examined. Thermal conductivity of the doped Gd0.7Yb0.3MgAl11O19 composition was found to be lower than that of the undoped GdMgAl11O19. In contrast, thermal expansion coefficient was found to be independent of the oxide composition and appears to be controlled by the magnetoplumbite crystal structure. Thermal conductivity testing of LaMgAl11O19 and LaMnAl11O19 magnetoplumbite oxide coatings plasma sprayed on NiCrAlY/Rene N5 superalloy substrates indicated resistance of these coatings to sintering even at temperatures as high as 1600 C.

  18. Structure sensitive properties of KTP-type crystals

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Adding various dopants during the growth of the parent KTiOPO4 (KTP) crystal has given rise to an extensive series of KTP-type crystals. The doped KTP or KTP-type crystals often have very subtle structural variations from pure KTP crystals. As a result of these structural changes the KTP-type crystals often exhibit different physical properties, which may be referred to as structure sensitive properties. It is possible to fine-tune the nonlinear optical properties of KTP crystals through doping. This results in a broad range of applications for KTP-type crystals.

  19. Lessons from crystal structures of kainate receptors

    DEFF Research Database (Denmark)

    Møllerud, Stine; Frydenvang, Karla Andrea; Pickering, Darryl S;

    2017-01-01

    synaptic transmission and modulate network excitability by regulating neurotransmitter release. Dysfunction of kainate receptors has been implicated in several neurological disorders such as epilepsy, schizophrenia and depression. Here we provide a review on the current understanding of kainate receptor...... structure and how they bind agonists, antagonists and ions. The first structure of the ligand-binding domain of the GluK1 subunit was reported in 2005, seven years after publication of the crystal structure of a soluble construct of the ligand-binding domain of the AMPA-type subunit GluA2. Today, a full...

  20. Microstructure and thermal change of texture of calcite crystals in ostrich eggshell Struthio camelus

    Energy Technology Data Exchange (ETDEWEB)

    Heredia, A. [Instituto de Ciencias Nucleares, UNAM. Circuito Exterior, Ciudad Universitaria, Coyoacan C.P. 04510 Mexico D.F. (Mexico) and Instituto de Fisica, UNAM. Apartado Postal 20-364, 01000 Mexico D.F. (Mexico)]. E-mail: heredia@fisica.unam.mx; Rodriguez-Hernandez, A.G. [Instituto de Fisica, UNAM. Apartado Postal 20-364, 01000 Mexico D.F. (Mexico); Lozano, L.F. [Instituto de Fisica, UNAM. Apartado Postal 20-364, 01000 Mexico D.F. (Mexico); Pena-Rico, M.A. [Instituto de Fisica, UNAM. Apartado Postal 20-364, 01000 Mexico D.F. (Mexico); Velazquez, R. [Instituto de Fisica, UNAM. Apartado Postal 20-364, 01000 Mexico D.F. (Mexico); Basiuk, V.A. [Instituto de Ciencias Nucleares, UNAM. Circuito Exterior, Ciudad Universitaria, Coyoacan C.P. 04510 Mexico D.F. (Mexico); Bucio, L. [Instituto de Fisica, UNAM. Apartado Postal 20-364, 01000 Mexico D.F. (Mexico)

    2005-01-01

    Eggshell from ostrich Struthio camelus, pristine and thermally treated in the range from room temperature to 550 deg. C, was investigated with low vacuum scanning electron microscopy (LVSEM), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and X-ray powder diffractometry (XRD). Different zones of the eggshell were analysed, including the protein-related, non-crystalline, inner organic membrane. After the high-temperature treatment (>500 deg. C), only crystallised calcite phase was found showing two main textures depending on the shell zone and the treatment temperature. In the crystal layer of the untreated samples, nanosized calcite crystals are organized with their c crystallographic axes highly aligned normal to eggshell surface (a very sharp gaussian angular distribution, {sigma}=0.14, was obtained by using the Rietveld method to model the preferred orientation function in the X-ray powder diffraction pattern). Elemental analysis revealed more Mg{sup 2+} in the crystal layer than in cone layer of the eggshell. A high nitrogen content in the organic membrane is associated to a proteinaceous phase. The cone and palisade layers are composed of needle-shaped calcite crystals, which are more crystallized than in the crystal layer and in average with their c crystallographic axes oriented in all directions except for the one perpendicular to the eggshell surface. Due to the complex structure and the amorphous/crystal phase interactions, the heating at about 500 deg. C texturizes the crystals orienting them mainly along the c-axes normal to the inner eggshell surface.

  1. Ambazone-lipoic acid salt: Structural and thermal characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kacso, Irina [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath street, 400293 Cluj-Napoca (Romania); Racz, Csaba-Pal; Santa, Szabolcs [Babes-Bolyai' University, Faculty of Chemistry, 11 Arany Janos street, Cluj-Napoca (Romania); Rus, Lucia [' Iuliu Hatieganu' University of Medicine and Pharmacy, Faculty of Pharmacy, 6 Louis Pasteur street, 400349 Cluj-Napoca (Romania); Dadarlat, Dorin; Borodi, Gheorghe [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath street, 400293 Cluj-Napoca (Romania); Bratu, Ioan, E-mail: ibratu@gmail.com [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath street, 400293 Cluj-Napoca (Romania)

    2012-12-20

    Highlights: Black-Right-Pointing-Pointer Salt of Ambazone with lipoic acid obtained by solvent-drop grinding. Black-Right-Pointing-Pointer Ambazone lipoate salt crystallizes in monoclinic system. Black-Right-Pointing-Pointer FTIR data suggest the deprotonation of the lipoic acid. Black-Right-Pointing-Pointer Thermal behaviour different of ambazone salt as compared to the starting compounds. - Abstract: A suitable method for increasing the solubility, dissolution rate and consequently the bioavailability of poor soluble acidic or basic drugs is their salt formation. The aim of this study is to investigate the structural and thermal properties of the compound obtained by solvent drop grinding (SDG) method at room temperature, starting from the 1:1 molar ratios of ambazone (AMB) and {alpha}-lipoic acid (LA). The structural characterization was performed with X-ray powder diffraction (XRPD) and infrared spectroscopy (FTIR). The thermal behaviour of the obtained compound (AMB{center_dot}LA) was investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG). The photopyroelectric calorimetry, in front detection configuration (FPPE), was applied to measure and compare the room temperature values of one dynamic thermal parameter (thermal effusivity) for starting and resulting compounds. Both structural and supporting calorimetric techniques pointed out a salt structure for AMB{center_dot}LA compound as compared to those of the starting materials.

  2. Investigations on the growth, optical, thermal, dielectric, and laser damage threshold properties of crystal violet dye-doped potassium acid phthalate single crystal

    Science.gov (United States)

    Rao, G. Babu; Rajesh, P.; Ramasamy, P.

    2016-03-01

    Influence of crystal violet dye with different concentration on potassium acid phthalate single crystal grown by conventional method has been studied. No change has been observed in the structure, whereas changes have been observed in the external morphology of the crystal when the dyes are incorporated in the crystal lattice. Thermogravimetric and differential thermal analyses show the onset decomposition temperatures to be at 302, 285, 284, and 285 °C for pure, 0.1, 0.3, and 0.5 mol% crystal violet-doped potassium acid phthalate crystals, respectively. The dielectric measurement was carried out on the grown crystals as a function of frequency at various temperatures. In addition, strong luminescent emission bands at 638, 648, and 640 nm were observed in which the relative intensity was found to be reversed as a result of doping concentration. The laser damage threshold value significantly increased for dye-doped crystal in comparison with pure crystal which may make it suitable for the solid-state dye laser applications.

  3. Negative thermal expansion due to negative area compressibility in TlGaSe2 semiconductor with layered crystalline structure

    Science.gov (United States)

    Seyidov, MirHasan Yu.; Suleymanov, Rauf A.

    2010-09-01

    We conducted comparison of the original experimental data of the temperature dependences of thermal expansion in crystals with layered crystalline structure. It is shown that in most crystals with layered structure (graphite, boron nitride, GaSe, GaS, and InSe) the effect of negative thermal expansion can be explained by the specific character of the phonon spectra. It was shown, that in contrast to other crystals with layered structure, negative thermal expansion in the layers' plane of TlGaSe2 is the result of negative area compressibility. We demonstrate that the thermal expansion of TlGaSe2 crystals can be controlled by illumination, external electric field, and thermal annealing. The nature of observed effects and a special mechanism of the negative area compressibility in TlGaSe2 crystals are discussed.

  4. Crystal structure of tris(hydroxylammonium orthophosphate

    Directory of Open Access Journals (Sweden)

    Malte Leinemann

    2015-11-01

    Full Text Available The crystal structure of the title salt, ([H3NOH]+3·[PO4]3−, consists of discrete hydroxylammonium cations and orthophosphate anions. The atoms of the cation occupy general positions, whereas the anion is located on a threefold rotation axis that runs through the phosphorus atom and one of the phosphate O atoms. In the crystal structure, cations and anions are linked by intermolecular O—H...O and N—H...O hydrogen bonds into a three-dimensional network. Altogether, one very strong O—H...O, two N—H...O hydrogen bonds of medium strength and two weaker bifurcated N—H...O interactions are observed.

  5. Crystal Structures of New Ammonium 5-Aminotetrazolates

    Directory of Open Access Journals (Sweden)

    Martin Lampl

    2014-11-01

    Full Text Available The crystal structures of three salts of anionic 5-aminotetrazole are described. The tetramethylammonium salt (P forms hydrogen-bonded ribbons of anions which accept weak C–H···N contacts from the cations. The cystamine salt (C2/c shows wave-shaped ribbons of anions linked by hydrogen bonds to screw-shaped dications. The tetramethylguanidine salt (P21/c exhibits layers of anions hydrogen-bonded to the cations.

  6. Crystal Structure of a New Cembranolide Diterpene

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new cembranoide deterpene was isolated from the soft coral Sinularia Tenella. The crystal and chemical structure of the title compound were determined by means of spectroscopic methods and X-ray diffraction analysis as (1R* , 4R* , 5S* , 12S* , 12R* )-9-acetoxy-cembr-8E, 15 (17)-dien-16,4-olide. It shows a moderate cytotoxicity against P 388 and L 1210 cell lines.

  7. Crystal structure of an archaeal actin homolog.

    Science.gov (United States)

    Roeben, Annette; Kofler, Christine; Nagy, István; Nickell, Stephan; Hartl, F Ulrich; Bracher, Andreas

    2006-04-21

    Prokaryotic homologs of the eukaryotic structural protein actin, such as MreB and ParM, have been implicated in determination of bacterial cell shape, and in the segregation of genomic and plasmid DNA. In contrast to these bacterial actin homologs, little is known about the archaeal counterparts. As a first step, we expressed a predicted actin homolog of the thermophilic archaeon Thermoplasma acidophilum, Ta0583, and determined its crystal structure at 2.1A resolution. Ta0583 is expressed as a soluble protein in T.acidophilum and is an active ATPase at physiological temperature. In vitro, Ta0583 forms sheets with spacings resembling the crystal lattice, indicating an inherent propensity to form filamentous structures. The fold of Ta0583 contains the core structure of actin and clearly belongs to the actin/Hsp70 superfamily of ATPases. Ta0583 is approximately equidistant from actin and MreB on the structural level, and combines features from both eubacterial actin homologs, MreB and ParM. The structure of Ta0583 co-crystallized with ADP indicates that the nucleotide binds at the interface between the subdomains of Ta0583 in a manner similar to that of actin. However, the conformation of the nucleotide observed in complex with Ta0583 clearly differs from that in complex with actin, but closely resembles the conformation of ParM-bound nucleotide. On the basis of sequence and structural homology, we suggest that Ta0583 derives from a ParM-like actin homolog that was once encoded by a plasmid and was transferred into a common ancestor of Thermoplasma and Ferroplasma. Intriguingly, both genera are characterized by the lack of a cell wall, and therefore Ta0583 could have a function in cellular organization.

  8. Modulation of the Band Gaps of Phononic Crystals with Thermal Effects

    Science.gov (United States)

    Aly, Arafa H.; Mehaney, Ahmed

    2015-11-01

    Band gaps of elastic waves, both in-plane and shear waves, propagating through one-dimensional perfect/defect phononic crystals (PnCs) that involve thermal effects are studied in this paper. Based on the transfer matrix method and Bloch theory, the expressions of the reflection coefficients and dispersion relation are presented. Elastic waves localization is obtained by immersing a defect layer through a perfect structure. Compared with the periodic structure, we observed that defected PnCs introduced localized modes or peaks within the phononic band gaps. Hence, Numerical simulations are performed to investigate the influences of the defect layer thickness and type on the number and intensity of the localized modes. Moreover, we have observed that temperature changes have prominent effects on the localized modes and band gaps width, especially at plane wave propagation. Such effects could change thermal properties of the PnCs structure such as thermal conductivity and could control the thermal emission contributed by phonons in many engineering structures.

  9. Crystal Structure Refinement of Synthetic Pure Gyrolite

    Directory of Open Access Journals (Sweden)

    Arūnas Baltušnikas

    2015-03-01

    Full Text Available Pure calcium silicate hydrate – gyrolite was prepared under the saturated steam pressure at 473 K temperature in rotating autoclave. The crystal structure of synthetic gyrolite was investigated by X-ray diffraction and refined using Le Bail, Rietveld and crystal structure modelling methods. Background, peak shape parameters and verification of the space group were performed by the Le Bail full pattern decomposition. Peculiarities of interlayer sheet X of gyrolite unit cell were highlighted by Rietveld refinement. Possible atomic arrangement in interlayer sheet X was solved by global optimization method. Most likelihood crystal structure model of gyrolite was calculated by final Rietveld refinement. It was crystallographically showed, that cell parameters are: a = 0.9713(2 nm, b = 0.9715(2 nm, c = 2.2442(3 nm and alfa = 95.48(2 º, beta = 91.45(2 °, gamma = l20.05(3 °.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5460

  10. Crystal structure, growth and nonlinear optical studies of isonicotinamide p-nitrophenol: A new organic crystal for optical limiting applications

    Science.gov (United States)

    Vijayalakshmi, A.; Vidyavathy, B.; Vinitha, G.

    2016-08-01

    Isonicotinamide p-nitrophenol (ICPNP), a new organic material, was synthesized using methanol solvent. Single crystals of ICPNP were grown using a slow evaporation solution growth technique. Crystal structure of ICPNP is elucidated by single crystal X-ray diffraction analysis. It belongs to monoclinic crystal system with space group of P21/c. It forms two dimensional networks by O-H…O, N-H…O and C-H…O hydrogen bonds. The molecular structure of ICPNP was further confirmed by Fourier transform infrared (FTIR) spectral analysis. The optical transmittance range and the lower cut-off wavelength (421 nm) with the optical band gap (2.90 eV) of the ICPNP crystal were determined by UV-vis-NIR spectral study. Thermal behavior of ICPNP was studied by thermo gravimetric and differential thermal analyses (TG/DTA). The relative dielectric permittivity was calculated for various temperature ranges. Laser damage threshold of ICPNP crystal was found to be 1.9 GW/cm2 using an Nd:YAG laser. A Z-scan technique was employed to measure the nonlinear absorption coefficient, nonlinear refractive index and nonlinear optical susceptibility. Optical limiting behavior of ICPNP was observed at 35 mW input power.

  11. Dynamics of metal-induced crystallization of ultrathin Ge films by rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Yuanxun; Huang, Shujuan; Shrestha, Santosh; Conibeer, Gavin [School of Photovoltaic and Renewable Energy Engineering, UNSW Australia, Sydney 2052 (Australia)

    2015-12-07

    Though Ge crystallization has been widely studied, few works investigate metal-induced crystallization of ultrathin Ge films. For 2 nm Ge films in oxide matrix, crystallization becomes challenging due to easy oxidation and low mobility of Ge atoms. Introducing metal atoms may alleviate these problems, but the functions and the behaviours of metal atoms need to be clarified. This paper investigates the crystallization dynamics of a multilayer structure 1.9 nm Ge/0.5 nm Al/1.5 nm Al{sub 2}O{sub 3} under rapid thermal annealing (RTA). The functions of metal atoms, like effective anti-oxidation, downshifting Raman peaks, and incapability to decrease crystallization temperature, are found and explained. The metal behaviours, such as inter-diffusion and defect generation, are supported with direct evidences, Al-Ge nanobicrystals, and Al cluster in Ge atoms. With these understandings, a two-step RTA process achieves high-quality 2 nm nanocrystal Ge films with Raman peak at 298 cm{sup −1} of FWHM 10.3 cm{sup −1} and atomic smooth interfaces.

  12. Lessons from crystal structures of kainate receptors.

    Science.gov (United States)

    Møllerud, Stine; Frydenvang, Karla; Pickering, Darryl S; Kastrup, Jette Sandholm

    2017-01-01

    Kainate receptors belong to the family of ionotropic glutamate receptors. These receptors assemble from five subunits (GluK1-5) into tetrameric ion channels. Kainate receptors are located at both pre- and postsynaptic membranes in the central nervous system where they contribute to excitatory synaptic transmission and modulate network excitability by regulating neurotransmitter release. Dysfunction of kainate receptors has been implicated in several neurological disorders such as epilepsy, schizophrenia and depression. Here we provide a review on the current understanding of kainate receptor structure and how they bind agonists, antagonists and ions. The first structure of the ligand-binding domain of the GluK1 subunit was reported in 2005, seven years after publication of the crystal structure of a soluble construct of the ligand-binding domain of the AMPA-type subunit GluA2. Today, a full-length structure has been determined of GluK2 by cryo electron microscopy to 7.6 Å resolution as well as 84 high-resolution crystal structures of N-terminal domains and ligand-binding domains, including agonist and antagonist bound structures, modulatory ions and mutations. However, there are still many unanswered questions and challenges in front of us. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'.

  13. Thermal fatigue. Fluid-structure interaction at thermal mixing events

    Energy Technology Data Exchange (ETDEWEB)

    Schuler, X.; Herter, K.H.; Moogk, S. [Stuttgart Univ. (Germany). MPA; Laurien, E.; Kloeren, D.; Kulenovic, R.; Kuschewski, M. [Stuttgart Univ. (Germany). Inst. of Nuclear Technology and Energy Systems

    2012-07-01

    In the framework of the network research project ''Thermal Fatigue - Basics of the system-, outflow- and material-characteristics of piping under thermal fatigue'' funded by the German Federal Ministry of Education and Research (BMBF) fundamental numerical and experimental investigations on the material behaviour under transient thermal-mechanical stress conditions (high cycle fatigue - HCF) are carried out. The project's background and its network of scientific working groups with their individual working tasks are briefly introduced. The main focus is especially on the joint research tasks within the sub-projects of MPA and IKE which are dealing with thermal mixing of flows in a T-junction configuration and the fluidstructure- interactions (FSI). Therefore, experiments were performed with the newly established FSI test facility at MPA which enables single-phase flow experiments of water in typical power plant piping diameters (DN40 and DN80) at high pressure (maximum 75 bar) and temperatures (maximum 280 C). The experimental results serve as validation data base for numerical modelling of thermal flow mixing by means of thermo-fluid dynamics simulations applying CFD techniques and carried out by IKE as well as for modelling of thermal and mechanical loads of the piping structure by structural mechanics simulations with FEM methods which are executed by MPA. The FSI test facility will be described inclusively the applied measurement techniques, e. g. in particular the novel near-wall LED-induced Fluorescence method for non-intrusive flow temperature measurements. First experimental data and numerical results from CFD and FEM simulations of the thermal mixing of flows in the T-junction are presented.

  14. A DIRECT DETERMINATION OF THE CRYSTAL STRUCTURE OF 2,3,4,6-TETRANITROANILINE,

    Science.gov (United States)

    ORGANIC NITROGEN COMPOUNDS, CRYSTAL STRUCTURE ), (* CRYSTAL STRUCTURE , EXPLOSIVES), (*EXPLOSIVES, CRYSTAL STRUCTURE ), AROMATIC COMPOUNDS, AMINES, NITRATES, LEAST SQUARES METHOD, FOURIER ANALYSIS, CHEMICAL BONDS.

  15. Crystal growth, FTIR and thermal characterization of bis(ethyltriphenylphosphonium) tetrabromomanganate(II) dihydrate crystals

    Indian Academy of Sciences (India)

    C Ilamaran; M Sethuram; M Dhandapani; G Amirthaganesan

    2012-05-01

    Single crystals of a novel compound, bis(ethyltriphenylphosphonium) tetrabromomanganate(II) dihydrate (BTP-Mn) were grown by solution growth-slow evaporation technique from aqueous solution of the compound at ambient temperature. The grown crystals were characterized by elemental analysis, powder X-ray diffraction, thermal analysis, nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infra-red spectroscopy (FTIR) techniques. The chemical composition of the compound was revealed by elemental analysis and its crystallinity was confirmed by powder X-ray diffraction. Thermal analysis confirmed that the compound was stable up to 125°C. The various kinds of protons and carbons present in the compound were confirmed by 1H NMR and 13C NMR technique respectively and the presence of phosphorous was confirmed by 31P NMR spectrum in the compound. The modes of vibration of different molecular groups present in the compound were identified by FTIR spectral analysis. The second harmonic generation behaviour was tested by Nd:YAG laser source.

  16. Temperature and thermal stress evolutions in sapphire crystal during the cooling process by heat exchanger method

    Science.gov (United States)

    Ma, Wencheng; Zhao, Wenhan; Wu, Ming; Ding, Guoqiang; Liu, Lijun

    2017-09-01

    Transient numerical calculations were carried out to predict the evolutions of temperature and thermal stress in sapphire single crystal during the cooling process by heat exchanger method (HEM). Internal radiation in the semitransparent sapphire crystal was taken into account using the finite volume method (FVM) in the global heat transfer model. The numerical results seem to indicate that the narrow bottom region of the sapphire crystal is subjected to high thermal stress during the cooling process, which could be responsible for the seed cracking of the as-grown crystal, while the thermal stress is relatively small in the central main body of the crystal, and is less than 10 MPa during the whole cooling process. The fast decrease of the thermal stress in the bottom region of the crystal during the initial stage of cooling process is dominated by the reduction of the cooling helium gas in the heat exchanger shaft, and is not significantly affected by the heating power reduction rate.

  17. Fourier Analysis and Structure Determination--Part III: X-ray Crystal Structure Analysis.

    Science.gov (United States)

    Chesick, John P.

    1989-01-01

    Discussed is single crystal X-ray crystal structure analysis. A common link between the NMR imaging and the traditional X-ray crystal structure analysis is reported. Claims that comparisons aid in the understanding of both techniques. (MVL)

  18. Polymorphism in phenobarbital: discovery of a new polymorph and crystal structure of elusive form V.

    Science.gov (United States)

    Roy, Saikat; Goud, N Rajesh; Matzger, Adam J

    2016-03-21

    This report highlights the discovery of a new polymorph of the anticonvulsant drug phenobarbital (PB) using polymer-induced heteronucleation (PIHn) and unravelling the crystal structure of the elusive form V. Both forms are characterized by structural, thermal and VT-Raman spectroscopy methods to elucidate phase transformation behavior and shed light on stability relationships.

  19. Crystal structure of iron-oxide nanoparticles synthesized from ferritin

    Energy Technology Data Exchange (ETDEWEB)

    Krispin, Michael, E-mail: michael.krispin@physik.uni-augsburg.de; Ullrich, Aladin, E-mail: aladin.ullrich@physik.uni-augsburg.de; Horn, Siegfried, E-mail: horn@physik.uni-augsburg.de [University of Augsburg, Institute of Physics (Germany)

    2012-02-15

    We have investigated the crystal structure of nanosized iron-oxide by X-ray diffraction (XRD), extended X-ray absorption fine structure measurements at the iron K-edge as well as by transmission electron microscopy (TEM). Iron-oxide nanoparticles were produced by thermal treatment of horse spleen ferritin molecules. The structure of these particles was compared to {alpha}-Fe{sub 2}O{sub 3} and {gamma}-Fe{sub 2}O{sub 3} nanopowder references. The thermal treatment of a submonolayer film of ferritin molecules results in pure {gamma}-Fe{sub 2}O{sub 3} nanoparticles, while for films above a certain thickness {alpha}-Fe{sub 2}O{sub 3} and {gamma}-Fe{sub 2}O{sub 3} coexist, exhibiting two different crystallite sizes. TEM shows a characteristic particle diameter of {approx}7 nm for {gamma}-Fe{sub 2}O{sub 3} resulting from thermal treatment of monolayers, consistent with the crystallite size of the {gamma}-phase as obtained from XRD measurements on multi-layered samples. XRD shows the {alpha}-Fe{sub 2}O{sub 3} phase to be characterized by a crystallite size of {approx}34 nm.

  20. THE CRYSTAL STRUCTURE OF 2-(4’-AMINO-5’AMINO PYRIMIDY) -2-PENTENE-4-ONE.

    Science.gov (United States)

    NITROGEN HETEROCYCLIC COMPOUNDS, CRYSTAL STRUCTURE ), (*AMINES, CRYSTAL STRUCTURE ), (*KETONES, CRYSTAL STRUCTURE ), CRYSTAL LATTICES, FOURIER ANALYSIS, LEAST SQUARES METHOD, MOLECULAR STRUCTURE, PYRIMIDINES, CHEMICAL BONDS

  1. Crystal structure of natural phaeosphaeride A

    Directory of Open Access Journals (Sweden)

    Victoria V. Abzianidze

    2015-08-01

    Full Text Available The asymmetric unit of the title compound, C15H23NO5, contains two independent molecules. Phaeosphaeride A contains two primary sections, an alkyl chain consisting of five C atoms and a cyclic system consisting of fused five- and six-membered rings with attached substituents. In the crystal, the molecules form layered structures. Nearly planar sheets, parallel to the (001 plane, form bilayers of two-dimensional hydrogen-bonded networks with the hydroxy groups located on the interior of the bilayer sheets. The network is constructed primarily of four O—H...O hydrogen bonds, which form a zigzag pattern in the (001 plane. The butyl chains interdigitate with the butyl chains on adjacent sheets. The crystal was twinned by a twofold rotation about the c axis, with refined major–minor occupancy fractions of 0.718 (6:0.282 (6.

  2. Determining crystal structures through crowdsourcing and coursework

    Science.gov (United States)

    Horowitz, Scott; Koepnick, Brian; Martin, Raoul; Tymieniecki, Agnes; Winburn, Amanda A.; Cooper, Seth; Flatten, Jeff; Rogawski, David S.; Koropatkin, Nicole M.; Hailu, Tsinatkeab T.; Jain, Neha; Koldewey, Philipp; Ahlstrom, Logan S.; Chapman, Matthew R.; Sikkema, Andrew P.; Skiba, Meredith A.; Maloney, Finn P.; Beinlich, Felix R. M.; Caglar, Ahmet; Coral, Alan; Jensen, Alice Elizabeth; Lubow, Allen; Boitano, Amanda; Lisle, Amy Elizabeth; Maxwell, Andrew T.; Failer, Barb; Kaszubowski, Bartosz; Hrytsiv, Bohdan; Vincenzo, Brancaccio; de Melo Cruz, Breno Renan; McManus, Brian Joseph; Kestemont, Bruno; Vardeman, Carl; Comisky, Casey; Neilson, Catherine; Landers, Catherine R.; Ince, Christopher; Buske, Daniel Jon; Totonjian, Daniel; Copeland, David Marshall; Murray, David; Jagieła, Dawid; Janz, Dietmar; Wheeler, Douglas C.; Cali, Elie; Croze, Emmanuel; Rezae, Farah; Martin, Floyd Orville; Beecher, Gil; de Jong, Guido Alexander; Ykman, Guy; Feldmann, Harald; Chan, Hugo Paul Perez; Kovanecz, Istvan; Vasilchenko, Ivan; Connellan, James C.; Borman, Jami Lynne; Norrgard, Jane; Kanfer, Jebbie; Canfield, Jeffrey M.; Slone, Jesse David; Oh, Jimmy; Mitchell, Joanne; Bishop, John; Kroeger, John Douglas; Schinkler, Jonas; McLaughlin, Joseph; Brownlee, June M.; Bell, Justin; Fellbaum, Karl Willem; Harper, Kathleen; Abbey, Kirk J.; Isaksson, Lennart E.; Wei, Linda; Cummins, Lisa N.; Miller, Lori Anne; Bain, Lyn; Carpenter, Lynn; Desnouck, Maarten; Sharma, Manasa G.; Belcastro, Marcus; Szew, Martin; Szew, Martin; Britton, Matthew; Gaebel, Matthias; Power, Max; Cassidy, Michael; Pfützenreuter, Michael; Minett, Michele; Wesselingh, Michiel; Yi, Minjune; Cameron, Neil Haydn Tormey; Bolibruch, Nicholas I.; Benevides, Noah; Kathleen Kerr, Norah; Barlow, Nova; Crevits, Nykole Krystyne; Dunn, Paul; Silveira Belo Nascimento Roque, Paulo Sergio; Riber, Peter; Pikkanen, Petri; Shehzad, Raafay; Viosca, Randy; James Fraser, Robert; Leduc, Robert; Madala, Roman; Shnider, Scott; de Boisblanc, Sharon; Butkovich, Slava; Bliven, Spencer; Hettler, Stephen; Telehany, Stephen; Schwegmann, Steven A.; Parkes, Steven; Kleinfelter, Susan C.; Michael Holst, Sven; van der Laan, T. J. A.; Bausewein, Thomas; Simon, Vera; Pulley, Warwick; Hull, William; Kim, Annes Yukyung; Lawton, Alexis; Ruesch, Amanda; Sundar, Anjali; Lawrence, Anna-Lisa; Afrin, Antara; Maheshwer, Bhargavi; Turfe, Bilal; Huebner, Christian; Killeen, Courtney Elizabeth; Antebi-Lerrman, Dalia; Luan, Danny; Wolfe, Derek; Pham, Duc; Michewicz, Elaina; Hull, Elizabeth; Pardington, Emily; Galal, Galal Osama; Sun, Grace; Chen, Grace; Anderson, Halie E.; Chang, Jane; Hewlett, Jeffrey Thomas; Sterbenz, Jennifer; Lim, Jiho; Morof, Joshua; Lee, Junho; Inn, Juyoung Samuel; Hahm, Kaitlin; Roth, Kaitlin; Nair, Karun; Markin, Katherine; Schramm, Katie; Toni Eid, Kevin; Gam, Kristina; Murphy, Lisha; Yuan, Lucy; Kana, Lulia; Daboul, Lynn; Shammas, Mario Karam; Chason, Max; Sinan, Moaz; Andrew Tooley, Nicholas; Korakavi, Nisha; Comer, Patrick; Magur, Pragya; Savliwala, Quresh; Davison, Reid Michael; Sankaran, Roshun Rajiv; Lewe, Sam; Tamkus, Saule; Chen, Shirley; Harvey, Sho; Hwang, Sin Ye; Vatsia, Sohrab; Withrow, Stefan; Luther, Tahra K.; Manett, Taylor; Johnson, Thomas James; Ryan Brash, Timothy; Kuhlman, Wyatt; Park, Yeonjung; Popović, Zoran; Baker, David; Khatib, Firas; Bardwell, James C. A.

    2016-09-01

    We show here that computer game players can build high-quality crystal structures. Introduction of a new feature into the computer game Foldit allows players to build and real-space refine structures into electron density maps. To assess the usefulness of this feature, we held a crystallographic model-building competition between trained crystallographers, undergraduate students, Foldit players and automatic model-building algorithms. After removal of disordered residues, a team of Foldit players achieved the most accurate structure. Analysing the target protein of the competition, YPL067C, uncovered a new family of histidine triad proteins apparently involved in the prevention of amyloid toxicity. From this study, we conclude that crystallographers can utilize crowdsourcing to interpret electron density information and to produce structure solutions of the highest quality.

  3. Synthesis and structural characterization of a single-crystal to single-crystal transformable coordination polymer.

    Science.gov (United States)

    Tian, Yuyang; Allan, Phoebe K; Renouf, Catherine L; He, Xiang; McCormick, Laura J; Morris, Russell E

    2014-01-28

    A single-crystal to single-crystal transformable coordination polymer compound was hydrothermally synthesized. The structural rearrangement is induced by selecting a ligand that contains both strong and weaker coordinating groups. Both hydrated and dehydrated structures were determined by single crystal X-ray analysis.

  4. Crystal structure of Cryptosporidium parvum pyruvate kinase.

    Directory of Open Access Journals (Sweden)

    William J Cook

    Full Text Available Pyruvate kinase plays a critical role in cellular metabolism of glucose by serving as a major regulator of glycolysis. This tetrameric enzyme is allosterically regulated by different effector molecules, mainly phosphosugars. In response to binding of effector molecules and substrates, significant structural changes have been identified in various pyruvate kinase structures. Pyruvate kinase of Cryptosporidium parvum is exceptional among known enzymes of protozoan origin in that it exhibits no allosteric property in the presence of commonly known effector molecules. The crystal structure of pyruvate kinase from C. parvum has been solved by molecular replacement techniques and refined to 2.5 Å resolution. In the active site a glycerol molecule is located near the γ-phosphate site of ATP, and the protein structure displays a partially closed active site. However, unlike other structures where the active site is closed, the α6' helix in C. parvum pyruvate kinase unwinds and assumes an extended conformation. In the crystal structure a sulfate ion is found at a site that is occupied by a phosphate of the effector molecule in many pyruvate kinase structures. A new feature of the C. parvum pyruvate kinase structure is the presence of a disulfide bond cross-linking the two monomers in the asymmetric unit. The disulfide bond is formed between cysteine residue 26 in the short N-helix of one monomer with cysteine residue 312 in a long helix (residues 303-320 of the second monomer at the interface of these monomers. Both cysteine residues are unique to C. parvum, and the disulfide bond remained intact in a reduced environment. However, the significance of this bond, if any, remains unknown at this time.

  5. Diterbium heptanickel: a crystal structure redetermination

    Directory of Open Access Journals (Sweden)

    Volodymyr Levytskyy

    2014-08-01

    Full Text Available The crystal structure of the title compound, Tb2Ni7, was redetermined from single-crystal X-ray diffraction data. In comparison with previous studies based on powder X-ray diffraction data [Lemaire et al. (1967. C. R. Acad. Sci. Ser. B, 265, 1280–1282; Lemaire & Paccard (1969. Bull. Soc. Fr. Mineral. Cristallogr. 92, 9–16; Buschow & van der Goot (1970. J. Less-Common Met. 22, 419–428], the present redetermination affords refined coordinates and anisotropic displacement parameters for all atoms. A partial occupation for one Tb atom results in the non-stoichiometric composition Tb1.962 (4Ni7. The title compound adopts the Ce2Ni7 structure type and can also be derived from the CaCu5 structure type as an intergrowth structure. The asymmetric unit contains two Tb sites (both site symmetries 3m. and five Ni sites (.m., mm2, 3m., 3m., -3m.. The two different coordination polyhedra of Tb are a Frank–Kasper polyhedron formed by four Tb and 12 Ni atoms and a pseudo Frank–Kasper polyhedron formed by two Tb and 18 Ni atoms. The four different coordination polyhedra of Ni are Frank–Kasper icosahedra formed by five Tb and seven Ni atoms, four Tb and eight Ni atoms, three Tb and nine Ni atoms, and six Tb and six Ni atoms, respectively.

  6. Thermal tuning the reversible optical band gap of self-assembled polystyrene photonic crystals

    Science.gov (United States)

    Vakili Tahami, S. H.; Pourmahdian, S.; Shirkavand Hadavand, B.; Azizi, Z. S.; Tehranchi, M. M.

    2016-11-01

    Nano-sized polymeric colloidal particles could undergo self-organization into three-dimensional structures to produce desired optical properties. In this research, a facile emulsifier-free emulsion polymerization method was employed to synthesize highly mono-disperse sub-micron polystyrene colloids. A high quality photonic crystal (PhC) structure was prepared by colloidal polystyrene. The reversible thermal tuning effect on photonic band gap position as well as the attenuation of the band gap was investigated in detail. The position of PBG can be tuned from 420 nm to 400 nm by varying the temperature of the PhC structure, reversibly. This reversible effect provides a reconfigurable PhC structure which could be used as thermo-responsive shape memory polymers.

  7. Beryllium, zinc and lead single crystals as a thermal neutron monochromators

    Energy Technology Data Exchange (ETDEWEB)

    Adib, M.; Habib, N. [Reactor Physics Department, NRC, Atomic Energy Authority, Cairo (Egypt); Bashter, I.I. [Physics Department, Faculty of Science, Zagazig University (Egypt); Morcos, H.N.; El-Mesiry, M.S. [Reactor Physics Department, NRC, Atomic Energy Authority, Cairo (Egypt); Mansy, M.S., E-mail: drmohamedmansy88@hotmail.com [Physics Department, Faculty of Science, Zagazig University (Egypt)

    2015-03-15

    Highlights: •Monochromatic features of Be, Zn and Pb single crystals. •Calculations of neutron reflectivity using a computer program MONO. •Optimum mosaic spread, thickness and cutting plane of single crystals. -- Abstract: The monochromatic features of Be, Zn and Pb single crystals are discussed in terms of orientation, mosaic spread, and thickness within the wavelength band from 0.04 up to 0.5 nm. A computer program MONO written in “FORTRAN-77”, has been adapted to carry out the required calculations. Calculations show that a 5 mm thick of beryllium (HCP structure) single crystal cut along its (0 0 2) plane having 0.6° FWHM are the optimum parameters when it is used as a monochromator with high reflected neutron intensity from a thermal neutron flux. Furthermore, at wavelengths shorter than 0.16 nm it is free from the accompanying higher order ones. Zinc (HCP structure) has the same parameters, with intensity much less than the latter. The same features are seen with lead (FCC structure) cut along its (3 1 1) plane with less reflectivity than the former. However, Pb (3 1 1) is more preferable than others at neutron wavelengths ⩽ 0.1 nm, since the glancing angle (θ ∼ 20°) is more suitable to carry out diffraction experiments. For a cold neutron flux, the first-order neutrons reflected from beryllium is free from the higher orders up to 0.36 nm. While for Zn single crystal is up to 0.5 nm.

  8. Crystal structure prediction from first principles: The crystal structures of glycine

    Science.gov (United States)

    Lund, Albert M.; Pagola, Gabriel I.; Orendt, Anita M.; Ferraro, Marta B.; Facelli, Julio C.

    2015-04-01

    Here we present the results of our unbiased searches of glycine polymorphs obtained using the genetic algorithms search implemented in MGAC, modified genetic algorithm for crystals, coupled with the local optimization and energy evaluation provided by Quantum Espresso. We demonstrate that it is possible to predict the crystal structures of a biomedical molecule using solely first principles calculations. We were able to find all the ambient pressure stable glycine polymorphs, which are found in the same energetic ordering as observed experimentally and the agreement between the experimental and predicted structures is of such accuracy that the two are visually almost indistinguishable.

  9. Orientational order controls crystalline and amorphous thermal transport in superatomic crystals

    Science.gov (United States)

    Ong, Wee-Liat; O'Brien, Evan S.; Dougherty, Patrick S. M.; Paley, Daniel W.; Fred Higgs, C., III; McGaughey, Alan J. H.; Malen, Jonathan A.; Roy, Xavier

    2017-01-01

    In the search for rationally assembled functional materials, superatomic crystals (SACs) have recently emerged as a unique class of compounds that combine programmable nanoscale building blocks and atomic precision. As such, they bridge traditional semiconductors, molecular solids, and nanocrystal arrays by combining their most attractive features. Here, we report the first study of thermal transport in SACs, a critical step towards their deployment as electronic, thermoelectric, and phononic materials. Using frequency domain thermoreflectance (FDTR), we measure thermal conductivity in two series of SACs: the unary compounds Co6E8(PEt3)6 (E = S, Se, Te) and the binary compounds [Co6E8(PEt3)6][C60]2. We find that phonons that emerge from the periodicity of the superstructures contribute to thermal transport. We also demonstrate a transformation from amorphous to crystalline thermal transport behaviour through manipulation of the vibrational landscape and orientational order of the superatoms. The structural control of orientational order enabled by the atomic precision of SACs expands the conceptual design space for thermal science.

  10. Tailoring quantum structures for active photonic crystals

    DEFF Research Database (Denmark)

    Kuznetsova, Nadezda

    This work is dedicated to the tailoring of quantum structures, with particular attention to the integration of selective area grown (SAG) active material into photonic crystal (PhC) slabs. The platform based on active PhC is vital to the realization of highly efficient elements with low energy...... consumption for on-chip and chip-to-chip optical communication. In order to develop metal-organic vapor phase epitaxial selective area etching and growth, a mask was fabricated in the HSQ e-beam resist including optimization of exposure and development conditions. By use of CBr4 as an etchant, in situ etching...... area and between the structures oriented along the [0-1-1] and [0-11] directions. Strong wavelength dependence with variations of the mask width of a few μm and opening sizes of hundreds of nanometers was observed. Incorporation of an active medium into PhC structures has showed promising results...

  11. Isolation and Crystal Structure of Horminone

    Institute of Scientific and Technical Information of China (English)

    陈晓; 廖仁安; 翁林红; 谢庆兰; 邓锋杰

    2000-01-01

    The horminone (C20H28O4, Mr= 332.85) was first isolated from the leaves of Rabdosia Serra (Maxim) Hara and its crystal structure was determined by X-ray diffraction method. Horminone is orthorhombic with space group P21P21P21, a=7.7186(7), b=9.5506(9), c=24.227(2) A, V=1785.9(3) A3, Z=4, Dc=1.236g/cm3, λ=0. 71073 A , μ(MoKα)=0. 085mm-1, F(000)=720. The structure was refined to R=0. 0369, wR=0.0978 for 2446 reflections with I>2σ(Ⅰ). X-ray diffraction analysis reveals that there are three six-membered rings in the title molecule. Ring A is in the chair conformation, ring C has the structure of quinone and there are two intermolecular hydrogen bonds between two molecules.

  12. Residual thermal stress of a mounted KDP crystal after cooling and its effects on second harmonic generation of a high-average-power laser

    Science.gov (United States)

    Su, Ruifeng; Liu, Haitao; Liang, Yingchun; Yu, Fuli

    2017-01-01

    Thermal problems are huge challenges for solid state lasers that are interested in high output power, cooling of the nonlinear optics is insufficient to completely solve the problem of thermally induced stress, as residual thermal stress remains after cooling, which is first proposed, to the best of our knowledge. In this paper a comprehensive model incorporating principles of thermodynamics, mechanics and optics is proposed, and it is used to study the residual thermal stress of a mounted KDP crystal after cooling process from mechanical perspective, along with the effects of the residual thermal stress on the second harmonic generation (SHG) efficiency of a high-average-power laser. Effects of the structural parameters of the mounting configuration of the KDP crystal on the residual thermal stress are characterized, as well as the SHG efficiency. The numerical results demonstrate the feasibility of solving the problems of residual thermal stress from the perspective on structural design of mounting configuration.

  13. Spectral, mechanical, thermal, optical and solid state parameters, of metal-organic bis(hydrogenmaleate)-CO(II) tetrahydrate crystal

    Energy Technology Data Exchange (ETDEWEB)

    Chandran, Senthilkumar [Centre for Crystal Growth, Department of Physics, SSN College of Engineering, Kalavakkam 603110 (India); Jagan, R. [Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036 (India); Paulraj, Rajesh, E-mail: rajeshp@ssn.edu.in [Centre for Crystal Growth, Department of Physics, SSN College of Engineering, Kalavakkam 603110 (India); Ramasamy, P. [Centre for Crystal Growth, Department of Physics, SSN College of Engineering, Kalavakkam 603110 (India)

    2015-10-15

    Metal-organic bis(hydrogenmaleate)-Co(II) tetrahydrate single crystals have been grown by slow evaporation solution growth technique at room temperature. The crystal structure and the unit cell parameters were analyzed from the X-ray diffraction studies. Single-crystal X-ray diffraction analyses reveal that the grown crystal belongs to triclinic system with the space group P-1. Functional groups in bis(hydrogenmaleate)-Co(II) tetrahydrate were identified by Fourier transform infrared spectral analysis. The peak observed at 663 cm{sup −1} is assigned to the (Co–O) stretching vibrations. The optical transmission of the crystal was studied by UV–vis–NIR spectral analysis. The photoluminescence emission studies were carried out for the title compound in a wide wavelength range between 350 nm and 550 nm at 303 K. Mechanical strength was tested by Vickers microhardness test. The laser damage threshold value has been determined using Nd:YAG laser operating at 1064 nm. At various frequencies and temperatures the dielectric behavior of the material was investigated. Solid state parameters such as plasma energy, Penn gap, Fermi energy and electronic polarizability were evaluated. Photoconductivity measurements were carried out for the grown crystal in the presence of DC electric field at room temperature. Thermal stability and decomposition of the crystal were studied by TG–DTA. The weight loss of the title compound occurs in different steps. - Graphical abstract: Molecular structure of the bis(hydrogenmaleate)-Co(II) tetrahydrate drawn at 40% ellipsoid probability level. - Highlights: • Bis(hydrogenmaleate)-Co(II) tetrahydrate single crystal is grown by slow evaporation method. • Structural and optical properties were discussed. • The title complex crystal is thermally stable up to 91 °C. • Plasma energy, Fermi energy and electronic polarizability are evaluated. • It exhibits positive photoconductivity.

  14. Tuning of a cavity in a silicon photonic crystal by thermal expansion of an elastomeric infill

    NARCIS (Netherlands)

    Erdamar, A.K.; Van Leest, M.M.; Picken, S.J.; Caro, J.

    2011-01-01

    We use an elastomer as infill material for a photonic crystal. As a result of the thermal-expansion-induced strongly negative thermal optical coefficient, this material is highly suitable for thermal tuning of the transmission of a cavity. This is demonstrated by global infilling of a hole-type sili

  15. Growth of large aluminum nitride single crystals with thermal-gradient control

    Energy Technology Data Exchange (ETDEWEB)

    Bondokov, Robert T.; Rao, Shailaja P.; Schowalter, Leo J.

    2017-02-28

    In various embodiments, non-zero thermal gradients are formed within a growth chamber both substantially parallel and substantially perpendicular to the growth direction during formation of semiconductor crystals, where the ratio of the two thermal gradients (parallel to perpendicular) is less than 10, by, e.g., arrangement of thermal shields outside of the growth chamber.

  16. Simultaneous measurements of anisotropic thermal diffusivity and thermal effusivity of liquid crystals using temperature wave analysis method

    Science.gov (United States)

    Ryu, Meguya; Morikawa, Junko

    2016-11-01

    Simultaneous measurements of anisotropic thermal diffusivity and thermal effusivity in the phase transition of the liquid crystal 4‧-(pentyloxy)-4-biphenyl carbonitrile (5OCB), Cry-53-N-68-Iso, are demonstrated using the temperature wave analysis method. A detailed calibration procedure for determining thermal diffusivity (α), thermal effusivity (e), thermal conductivity (λ), and heat capacity per unit volume (Cp ρ) is proposed utilizing hexaethylene glycol monododecyl ether (C12E6) as a calibration material, the heat capacity of which is precisely determined using a calorimetric method.

  17. Crystal structure of (ferrocenylmethyldimethylammonium hydrogen oxalate

    Directory of Open Access Journals (Sweden)

    Mamadou Ndiaye

    2015-08-01

    Full Text Available The crystal structure of the title salt, [Fe(C5H5(C8H13N](HC2O4, consists of discrete (ferrocenylmethyldimethylammonium cations and hydrogen oxalate anions. The anions are connected through a strong O—H...O hydrogen bond, forming linear chains running parallel to [100]. The cations are linked to the anions through bifurcated N—H...(O,O′ hydrogen bonds. Weak C—H...π interactions between neighbouring ferrocenyl moieties are also observed.

  18. [Crystal and molecular structure of cytisine salts].

    Science.gov (United States)

    Niedźwiecka, Julia; Przybył, Anna K; Kubicki, Maciej

    2012-01-01

    Cytisine is an alkaloid of plant origin. It is a toxic substance, obtained on an industrial scale from Laburnum anagyroides also known as common laburnum. Today is used in the preparation of anti-smoking products as an agonist of nicotinic receptors nAChR-alpha4beta2. Thanks to crystallographic methods we can examine and describe with high accuracy the actual structure of complex chemical compounds. This work aims to present a series of tests carried out on crystals of cytisine salts, after a prior isolation of cytisine from the seeds of laburnum anagyroides.

  19. Crystal structure of hexaaquadichloridoytterbium(III chloride

    Directory of Open Access Journals (Sweden)

    Kevin M. Knopf

    2015-06-01

    Full Text Available The crystal structure of the title compound, [YbCl2(H2O6]Cl, was determined at 110 K. Samples were obtained from evaporated acetonitrile solutions containing the title compound, which consists of a [YbCl2(H2O6]+ cation and a Cl− anion. The cations in the title compound sit on a twofold axis and form O—H...Cl hydrogen bonds with the nearby Cl− anion. The coordination geometry around the metal centre forms a distorted square antiprism. The ytterbium complex is isotypic with the europium complex [Tambrornino et al. (2014. Acta Cryst. E70, i27].

  20. Crystal Structure of Marburg Virus VP24

    OpenAIRE

    Zhang, Adrianna P. P.; Bornholdt, Zachary A.; Abelson, Dafna M.; Saphire, Erica Ollmann

    2014-01-01

    The VP24 protein plays an essential, albeit poorly understood role in the filovirus life cycle. VP24 is only 30% identical between Marburg virus and the ebolaviruses. Furthermore, VP24 from the ebolaviruses is immunosuppressive, while that of Marburg virus is not. The crystal structure of Marburg virus VP24, presented here, reveals that although the core is similar between the viral genera, Marburg VP24 is distinguished by a projecting β-shelf and an alternate conformation of the N-terminal p...

  1. Crystal structure of Marburg virus VP24.

    Science.gov (United States)

    Zhang, Adrianna P P; Bornholdt, Zachary A; Abelson, Dafna M; Saphire, Erica Ollmann

    2014-05-01

    The VP24 protein plays an essential, albeit poorly understood role in the filovirus life cycle. VP24 is only 30% identical between Marburg virus and the ebolaviruses. Furthermore, VP24 from the ebolaviruses is immunosuppressive, while that of Marburg virus is not. The crystal structure of Marburg virus VP24, presented here, reveals that although the core is similar between the viral genera, Marburg VP24 is distinguished by a projecting β-shelf and an alternate conformation of the N-terminal polypeptide.

  2. Elasticity of some mantle crystal structures. II.

    Science.gov (United States)

    Wang, H.; Simmons, G.

    1973-01-01

    The single-crystal elastic constants are determined as a function of pressure and temperature for rutile structure germanium dioxide (GeO2). The data are qualitatively similar to those of rutile TiO2 measured by Manghnani (1969). The compressibility in the c direction is less than one-half that in the a direction, the pressure derivative of the shear constant is negative, and the pressure derivative of the bulk modulus has a relatively high value of about 6.2. According to an elastic strain energy theory, the negative shear modulus derivative implies that the kinetic barrier to diffusion decreases with increasing pressure.

  3. Crystal structure of a DNA catalyst.

    Science.gov (United States)

    Ponce-Salvatierra, Almudena; Wawrzyniak-Turek, Katarzyna; Steuerwald, Ulrich; Höbartner, Claudia; Pena, Vladimir

    2016-01-14

    Catalysis in biology is restricted to RNA (ribozymes) and protein enzymes, but synthetic biomolecular catalysts can also be made of DNA (deoxyribozymes) or synthetic genetic polymers. In vitro selection from synthetic random DNA libraries identified DNA catalysts for various chemical reactions beyond RNA backbone cleavage. DNA-catalysed reactions include RNA and DNA ligation in various topologies, hydrolytic cleavage and photorepair of DNA, as well as reactions of peptides and small molecules. In spite of comprehensive biochemical studies of DNA catalysts for two decades, fundamental mechanistic understanding of their function is lacking in the absence of three-dimensional models at atomic resolution. Early attempts to solve the crystal structure of an RNA-cleaving deoxyribozyme resulted in a catalytically irrelevant nucleic acid fold. Here we report the crystal structure of the RNA-ligating deoxyribozyme 9DB1 (ref. 14) at 2.8 Å resolution. The structure captures the ligation reaction in the post-catalytic state, revealing a compact folding unit stabilized by numerous tertiary interactions, and an unanticipated organization of the catalytic centre. Structure-guided mutagenesis provided insights into the basis for regioselectivity of the ligation reaction and allowed remarkable manipulation of substrate recognition and reaction rate. Moreover, the structure highlights how the specific properties of deoxyribose are reflected in the backbone conformation of the DNA catalyst, in support of its intricate three-dimensional organization. The structural principles underlying the catalytic ability of DNA elucidate differences and similarities in DNA versus RNA catalysts, which is relevant for comprehending the privileged position of folded RNA in the prebiotic world and in current organisms.

  4. Syntheses and Crystal Structures of Pyrazoline Derivants

    Institute of Scientific and Technical Information of China (English)

    SHI Hai-Bin; JI Shun-Jun; ZHANG Yong

    2005-01-01

    Two pyrazoline derivants 1-(2-benzothiazole)-3-phenyl-5-(3-thiophene)-2- pyrazoline (BPTP) and 1-(2-benzothiazole)-3-(2-thiophene)-5-phenyl-2-pyrazoline (BTPP) have been synthe- sized and their crystal structures were determined by X-ray single-crystal diffraction.Crystal of BPTP belongs to triclinic, space group P with a = 9.4430(11), b = 9.9384(13), c = 9.9394(13) (A), α = 83.107(10), β = 79.947(10), γ = 70.221(7)o, V = 862.42(19) (A)3, Z = 2, Dc = 1.392 g/cm3, μ(MoKα) = 0.316 mm-1, F(000) = 376, λ = 0.71070 (A), (Δρ)max = 0.348, (Δρ)min = -0.481 e/(A)3, the final R = 0.0407 and wR = 0.1055 for 2844 observed reflections with I > 2σ(I).Crystal of BTPP is of monoclinic, space group P21/c with a = 11.6158(17), b = 11.2796(18), c = 13.082(2) (A), α = 90, β = 91.087(4), γ = 90o, V = 1713.7(5) (A)3, Z = 4, Dc = 1.401 g/cm3, μ(MoKα) = 0.318 mm-1, Mr = 361.07, F(000) = 752, λ = 0.71070 (A), (Δρ)max = 0.322, (Δρ)min = -0.330 e/(A)3, the final R = 0.0563 and wR = 0.1058 for 3434 observed reflections with I > 2σ(I).

  5. X-ray analysis of mechanical and thermal effects induced by femtosecond laser treatment of aluminum single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Valette, S. [Laboratoire Traitement du Signal et Instrumentation, Universite Jean Monnet, UMR CNRS 5516, 10 rue Barrouin 42000 Saint-Etienne (France)]. E-mail: stephane.valette@ec-lyon.fr; Le Harzic, R. [Laboratoire Traitement du Signal et Instrumentation, Universite Jean Monnet, UMR CNRS 5516, 10 rue Barrouin 42000 Saint-Etienne (France); Audouard, E. [Laboratoire Traitement du Signal et Instrumentation, Universite Jean Monnet, UMR CNRS 5516, 10 rue Barrouin 42000 Saint-Etienne (France); Huot, N. [Laboratoire Traitement du Signal et Instrumentation, Universite Jean Monnet, UMR CNRS 5516, 10 rue Barrouin 42000 Saint-Etienne (France); Fillit, R. [Ecole Nationale Superieure des Mines de Saint-Etienne, 158 Cours Fauriel, 42023 Saint-Etienne Cedex 2 (France); Fortunier, R. [Ecole Nationale Superieure des Mines de Saint-Etienne, 158 Cours Fauriel, 42023 Saint-Etienne Cedex 2 (France)

    2006-04-30

    Surface marking of aluminum single crystal is performed with femtosecond laser pulses. X-ray analysis allows to measure thermal and mechanical effects induced by the femtosecond laser pulses. These effects are estimated by comparing the pole figures (crystallinity) and the broadening of the diffraction peaks (mechanical contribution) before and after the laser irradiation. The results show that the femtosecond laser treatment ensures a re-crystallization of the structure and the presence of mechanical residual stresses. The analysis of the pole figures provides the sign of a re-crystallization on smaller volumes compared to initial ones. After the laser irradiation, the crystallization is perfectly oriented like the (1 1 0) orientation of the massive sample. Moreover, following the laser treatment, we show that the crystallographic structure is purer than the initial one. We also prove that the laser effect is persistent on a typical scale of 10 {mu}m beyond the surface.

  6. Investigations on Preparation, Crystal Structure and Thermal Stability of Bis(O-ethylcarbonodithiolato-S ,S′) (1,10-phenanthroline-N1,N10)cobalt(Ⅱ) Complex: [Co(Et-XA)2·phen] ·H2O (XA = xanthate)

    Institute of Scientific and Technical Information of China (English)

    JIAN, Fang-Fang; LI, Yan; WANG, Huan-Xiang; JIAO, Kui

    2003-01-01

    [Co(Et-XA)2-phen]· H2O was prepared by adding 1,10-phenanthroline to the EtOH solution of bis (O-ethylcarbonodithiolato)cobalt(H) [Co(Et-XA)2]. The single crystal structure has been determined by X-ray diffraction analysis. The compound is orthorhombic with space group Pna21 and unit-cell parameters a = 1.0290(2) nm, b = 1.4550(3) nm and c = 1.4860(3)nm. The geometry of each Co atom which coordinates with four S atoms from two xanthate anions and two N atoms from phenanthroline ligand, is a distorted octahedron. The brown crystals were examined by elemental analysis, FT-IR, UV spectra and thermogravimetric-differential thermal analysis (TGDTA). Thermal decomposition of the compound takes place in several steps. In the first step, the compound releases 1, 10-phenanthroline ligand, then loses the H2O molecules. In the second step, the complex decomposes to CoS3. The final product of thermal decomposition is CoS. Elemental analysis, Irand UV spectra are in agreement with the proposd structure.

  7. Structural-Thermal-Optical-Performance (STOP) Analysis

    Science.gov (United States)

    Bolognese, Jeffrey; Irish, Sandra

    2015-01-01

    The presentation will be given at the 26th Annual Thermal Fluids Analysis Workshop (TFAWS 2015) hosted by the Goddard Spaceflight Center (GSFC) Thermal Engineering Branch (Code 545). A STOP analysis is a multidiscipline analysis, consisting of Structural, Thermal and Optical Performance Analyses, that is performed for all space flight instruments and satellites. This course will explain the different parts of performing this analysis. The student will learn how to effectively interact with each discipline in order to accurately obtain the system analysis results.

  8. Construction of thermal ratchet structural test facility

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeong Yeon; Kim, J. B.; Yoo, B

    2000-12-01

    The objective of this study is to setup the thermal ratchet test facility to validate the NONSTA code that is under development for the inelastic structure analysis and to characterize the thermal ratchet behavior through structural thermal ratchet test. Thermal ratchet phenomenon, a progressive inelastic deformation can occur in the liquid metal reactor operating at high temperature above 500 deg C due to the moving temperature distribution along the axial direction as the hot free surface moves up and down due to the cyclic heat-up and cool-down of reactor operation. Thermal ratchet can cause a severe damage to the reactor structure. The structural ratchet test was performed and the test results were compared with those of the analysis using Chaboche constitutive model. The fabrication of the ratchet test facility was completed in 1/4 of 2000, the performance test was carried out in the second quarter of 2000, the noise reduction of thermocouples, measurements by laser displacement sensor with data acquisition system was carried out in the third quarter and the test results compared with those of the inelastic structure analysis in the forth quarter of 2000, which showed reasonable agreement with those of the tests.

  9. Thermal fluctuations and phase diagrams of the phase-field crystal model with pinning.

    Science.gov (United States)

    Ramos, J A P; Granato, E; Achim, C V; Ying, S C; Elder, K R; Ala-Nissila, T

    2008-09-01

    We study the influence of thermal fluctuations in the phase diagram of a recently introduced two-dimensional phase field crystal model with an external pinning potential. The model provides a continuum description of pinned lattice systems allowing for both elastic deformations and topological defects. We introduce a nonconserved version of the model and determine the ground-state phase diagram as a function of lattice mismatch and strength of the pinning potential. Monte Carlo simulations are used to determine the phase diagram as a function of temperature near commensurate phases. The results show a rich phase diagram with commensurate, incommensurate, and liquidlike phases with a topology strongly dependent on the type of ordered structure. A finite-size scaling analysis of the melting transition for the c(2x2) commensurate phase shows that the thermal correlation length exponent nu and specific heat behavior are consistent with the Ising universality class as expected from analytical arguments.

  10. Thermal profiles, crystallization behaviors and microstructure of diacylglycerol-enriched palm oil blends with diacylglycerol-enriched palm olein.

    Science.gov (United States)

    Xu, Yayuan; Zhao, Xiaoqing; Wang, Qiang; Peng, Zhen; Dong, Cao

    2016-07-01

    To elucidate the possible interaction mechanisms between DAG-enriched oils, this study investigated how mixtures of DAG-enriched palm-based oils influenced the phase behavior, thermal properties, crystallization behaviors and the microstructure in binary fat blends. DAG-enriched palm oil (PO-DAGE) was blended with DAG-enriched palm olein (POL-DAGE) in various percentages (0%, 10%, 30%, 50%, 70%, 90%, 100%). Based on the observation of iso-solid diagram and phase diagram, the binary mixture of PO-DAGE/POL-DAGE showed a better compatibility in comparison with their corresponding original blends. DSC thermal profiles exhibited that the melting and crystallization properties of PO-DAGE/POL-DAGE were distinctively different from corresponding original blends. Crystallization kinetics revealed that PO-DAGE/POL-DAGE blends displayed a rather high crystallization rate and exhibited no spherulitic crystal growth. From the results of polarized light micrographs, PO-DAGE/POL-DAGE blends showed more dense structure with very small needle-like crystals than PO/POL. X-ray diffraction evaluation revealed when POL-DAGE was added in high contents to PO-DAGE, above 30%, β-polymorph dominated, and the mount of β' forms crystals was decreasing.

  11. Band structure characteristics of T-square fractal phononic crystals

    Institute of Scientific and Technical Information of China (English)

    Liu Xiao-Jian; Fan You-Hua

    2013-01-01

    The T-square fractal two-dimensional phononic crystal model is presented in this article.A comprehensive study is performed for the Bragg scattering and locally resonant fractal phononic crystal.We find that the band structures of the fractal and non-fractal phononic crystals at the same filling ratio are quite different through using the finite element method.The fractal design has an important impact on the band structures of the two-dimensional phononic crystals.

  12. Crystal structure of yeast Sco1

    Energy Technology Data Exchange (ETDEWEB)

    Abajian, Carnie; Rosenzweig, Amy C. (NWU)

    2010-03-05

    The Sco family of proteins are involved in the assembly of the dinuclear CuA site in cytochrome c oxidase (COX), the terminal enzyme in aerobic respiration. These proteins, which are found in both eukaryotes and prokaryotes, are characterized by a conserved CXXXC sequence motif that binds copper ions and that has also been proposed to perform a thiol:disulfide oxidoreductase function. The crystal structures of Saccharomyces cerevisiae apo Sco1 (apo-ySco1) and Sco1 in the presence of copper ions (Cu-ySco1) were determined to 1.8- and 2.3-{angstrom} resolutions, respectively. Yeast Sco1 exhibits a thioredoxin-like fold, similar to that observed for human Sco1 and a homolog from Bacillus subtilis. The Cu-ySco1 structure, obtained by soaking apo-ySco1 crystals in copper ions, reveals an unexpected copper-binding site involving Cys181 and Cys216, cysteine residues present in ySco1 but not in other homologs. The conserved CXXXC cysteines, Cys148 and Cys152, can undergo redox chemistry in the crystal. An essential histidine residue, His239, is located on a highly flexible loop, denoted the Sco loop, and can adopt positions proximal to both pairs of cysteines. Interactions between ySco1 and its partner proteins yeast Cox17 and yeast COX2 are likely to occur via complementary electrostatic surfaces. This high-resolution model of a eukaryotic Sco protein provides new insight into Sco copper binding and function.

  13. Modeling of photonic crystal waveguide structures

    Science.gov (United States)

    Richter, Ivan; Kwiecien, Pavel; Šiňor, Milan; Haiduk, Adam

    2007-05-01

    Photonic crystal (PhC) structures and photonic structures based on them represent nowadays very promising structures of artificial origin. Since they exhibit very specific properties and characteristics that can be very difficult (or even impossible) to realize by other means, they represent a significant part of new artificially made metamaterial classes. For studying and modeling properties of PhC structures, we have applied, implemented and partially improved various complementary techniques: the 2D plane wave expansion (PWE) method, and the 2D finite-difference time-domain (FDTD) method with perfectly matched layers. Also, together with these in-house methods, other tools available in the field have been applied, including, e.g. MIT MPB (PWE), F2P (FDTD) and CAMFR (bidirectional expansion and propagation mode matching method) packages. We have applied these methods to several PhC waveguide structure examples, studying the effects of varying the key parameters and geometry. Such a study is relevant for proper understanding of physical mechanisms and for optimization and fabrication recommendations. Namely, in this contribution, we have concentrated on several examples of PhC waveguide structure simulations, of two types of guides (dielectric-rode type and air-hole type), with several geometries: rectangular lattice with either rectangular or chessboard inclusions. The modeling results are compared and discussed.

  14. Temperature dependent spin structures in Hexaferrite crystal

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Y.C. [Center for Condensed Matter Sciences, National Taiwan University, Taipei 106, Taiwan (China); Lin, J.G., E-mail: jglin@ntu.edu.tw [Center for Condensed Matter Sciences, National Taiwan University, Taipei 106, Taiwan (China); Chun, S.H.; Kim, K.H. [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2016-01-01

    In this work, the Hexaferrite Ba{sub 0.5}Sr{sub 1.5}Zn{sub 2}Fe{sub 12}O{sub 22} (BSZFO) is studied due to its interesting characteristics of long-wavelength spin structure. Ferromagnetic resonance (FMR) is used to probe the magnetic states of BSZFO single crystal and its temperature dependence behavior is analyzed by decomposing the multiple lines of FMR spectra into various phases. Distinguished phase transition is observed at 110 K for one line, which is assigned to the ferro(ferri)-magnetic transition from non-collinear to collinear spin state. - Highlights: • For the first time Ferromagnetic Resonance is used to probe the local magnetic structure of Ba{sub 0.5}Sr{sub 1.5}Zn{sub 2}Fe{sub 12}O{sub 22.} • The multiphases in the single crystal is identified, which provides important information toward its future application for the magnetoelectric devices.

  15. Six novel transition-metal phosphite compounds, with structure related to yavapaiite: Crystal structures and magnetic and thermal properties of A{sup I}[M{sup III}(HPO{sub 3}){sub 2}] (A=K, NH{sub 4}, Rb and M=V, Fe)

    Energy Technology Data Exchange (ETDEWEB)

    Hamchaoui, Farida [Laboratoire des Sciences des Materiaux, Faculte de Chimie, Universite des Sciences et de la Technologie Houari Boumediene, BP 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Alonzo, Veronique [Sciences Chimiques de Rennes, UMR6226, Ecole Nationale Superieure de Chimie de Rennes, CNRS, Avenue du General Leclerc, CS 50837, 35708 Rennes Cedex 7 (France); Universite Europeenne de Bretagne (France); Venegas-Yazigi, Diego [Facultad de Quimia y Biologia, Universitad de Santiago de Chile, USACH, Casilla, 40 Correo 33, Santiago (Chile); Rebbah, Houria [Laboratoire des Sciences des Materiaux, Faculte de Chimie, Universite des Sciences et de la Technologie Houari Boumediene, BP 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Le Fur, Eric, E-mail: eric.le-fur@ensc-rennes.fr [Sciences Chimiques de Rennes, UMR6226, Ecole Nationale Superieure de Chimie de Rennes, CNRS, Avenue du General Leclerc, CS 50837, 35708 Rennes Cedex 7 (France); Universite Europeenne de Bretagne (France)

    2013-02-15

    Six new transition metal(III) phosphites A{sup I}[V{sup III}(HPO{sub 3}){sub 2}], where A=K (1), NH{sub 4} (2) and Rb (3) and A{sup I}[Fe{sup III}(HPO{sub 3}){sub 2}] where A=K (4), NH{sub 4} (5) and Rb (6) have been synthesized under hydrothermal conditions and the solid-state structures were solved from single-crystal X-ray diffraction data. These compounds crystallize in the hexagonal system, space group P6{sub 3}mc (no. 186), with a=5.3294(2) A and c=12.3130(5) A for 1, a=5.3330(2) A and c=12.8760(4) A for 2, a=5.3459(2) A and c=12.6850(8) A for 3, a=5.3256(1) A and c=12.2362(3) A for 4, a=5.3229(2) A and c=12.8562(4) A for 5, a=5.3393(2) A and c=12.6913(5) A for 6, with Z=2 in the six phases. The crystal structures of these compounds are isotypic and exhibit a layered structure stacked along the c-axis with the A{sup +} cations located in the interlayer space. The [M{sup III}(HPO{sub 3}){sub 2}]{sup -} sheets are formed by MO{sub 6} octahedra interconnected by HPO{sub 3} tetrahedral phosphite oxoanions through sharing vertices. Thermal analysis shows a large range of stability for compounds containing potassium and rubidium cations with decomposition starting around 550 K for stable compounds and above 840 K for the most stable compounds leading in general to pyrophosphate compounds. Triangular nets of metallic centers are observed within the layers in which antiferromagnetic interactions are evidenced by magnetic susceptibility measurements suggesting magnetic frustration. - Graphical abstract: Six new transition metal(III) phosphites A{sup I}[M{sup III}(HPO{sub 3}){sub 2}], where A=K, NH{sub 4}, Rb and M=V, Fe, have been synthesized. The crystal structures of these compounds are isotypic and exhibit a lamellar structure related to Yavapaiite. The M(HPO{sub 3}){sub 2} layers separated by cationic species present the metallic centers in a triangular arrangement. Bulk antiferromagnetic behavior is observed for all the studied compounds. Highlights: Black

  16. 1.2.4. Synthesis, crystal structure and thermal stability property of Ni(aze(4,4′ –bipy(H2O based on longer-spanning azelaic acid and 4,4′ -bipyridine ligands

    Directory of Open Access Journals (Sweden)

    Ge Song, Feng Ying Bai*, Yan Xie, Yong Heng Xing.

    2014-04-01

    Full Text Available Abstract: One new three-dimensional (3D supramolecular longer-spanning azelaic acid (H2aze complex: Ni(aze(4,4′– bipy(H2O (4,4′-bipy = 4,4′-bipyridine has been synthesized using hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, UV spectrum, powder X-ray diffraction, TG analysis and single crystal X–ray diffraction. Structural analysis reveals that the title complex is six-coordinate and connected by the azelaic acid and 4,4′-bipy ligands to generate a 2D planar structure, further linked through the interaction of hydrogen bond of C–H···O to form a 3D supramolecular structure . Supporting information: FT-IR, UV-Vis, X-Ray, Cif file

  17. Crystal growth, perfection, linear and nonlinear optical, photoconductivity, dielectric, thermal and laser damage threshold properties of 4-methylimidazolium picrate: an interesting organic crystal for photonic and optoelectronic devices

    Science.gov (United States)

    Rajesh, K.; Arun, A.; Mani, A.; Praveen Kumar, P.

    2016-10-01

    The 4-methylimidazolium picrate has been synthesized and characterized successfully. Single and powder x-ray diffraction studies were conducted which confirmed the crystal structure, and the value of the strain was calculated. The crystal perfection was determined by a HRXR diffractometer. The transmission spectrum exhibited a better transmittance of the crystal in the entire visible region with a lower cut-off wavelength of 209 nm. The linear absorption value was calculated by the optical limiting method. A birefringence study was also carried out. Second and third order nonlinear optical properties of the crystal were found by second harmonic generation and the z-scan technique. The crystals were also characterized by dielectric measurement and a photoconductivity analyzer to determine the dielectric property and the optical conductivity of the crystal. The laser damage threshold activity of the grown crystal was studied by a Q-switched Nd:YAG laser beam. Thermal studies established that the compound did not undergo a phase transition and was stable up to 240 °C.

  18. Syntheses and Crystal Structures of Ferrocenoindenes

    Directory of Open Access Journals (Sweden)

    Gerhard Laus

    2013-02-01

    Full Text Available Ferrocenoindenes display planar chirality and thus represent valuable ligands for asymmetric catalysis. Here, we report on the synthesis of novel 3-(1,1-dibromomethyleneferroceno[1,2-a]indene, (Z-3-(1-bromomethylene-6-iodoferroceno[1,2-a]indene, and benzo[5,6-f]ferroceno[2,3,a]inden-1-one. Any application-oriented design of chiral catalysts requires fundamental knowledge about the ligands involved, not only in terms of atom-connectivity, but also in terms of their three-dimensional structure and steric demand. Therefore, the crystal structures of 2-ferrocenylbenzoic acid, ferroceno[1,2-a]indene, and (Z-3-(1-bromomethylene-6-iodoferroceno[1,2-a]indene have been determined. The bond-lengths that can be retrieved therefrom also allow for an estimation of the reactivity of the aryl-iodo, bromo-methylidene and dibromomethylidene moieties.

  19. Crystal structure of human nicotinamide riboside kinase.

    Science.gov (United States)

    Khan, Javed A; Xiang, Song; Tong, Liang

    2007-08-01

    Nicotinamide riboside kinase (NRK) has an important role in the biosynthesis of NAD(+) as well as the activation of tiazofurin and other NR analogs for anticancer therapy. NRK belongs to the deoxynucleoside kinase and nucleoside monophosphate (NMP) kinase superfamily, although the degree of sequence conservation is very low. We report here the crystal structures of human NRK1 in a binary complex with the reaction product nicotinamide mononucleotide (NMN) at 1.5 A resolution and in a ternary complex with ADP and tiazofurin at 2.7 A resolution. The active site is located in a groove between the central parallel beta sheet core and the LID and NMP-binding domains. The hydroxyl groups on the ribose of NR are recognized by Asp56 and Arg129, and Asp36 is the general base of the enzyme. Mutation of residues in the active site can abolish the catalytic activity of the enzyme, confirming the structural observations.

  20. Crystal Structure of Human Nicotinamide Riboside Kinase

    Energy Technology Data Exchange (ETDEWEB)

    Khan,J.; Xiang, S.; Tong, L.

    2007-01-01

    Nicotinamide riboside kinase (NRK) has an important role in the biosynthesis of NAD{sup +} as well as the activation of tiazofurin and other NR analogs for anticancer therapy. NRK belongs to the deoxynucleoside kinase and nucleoside monophosphate (NMP) kinase superfamily, although the degree of sequence conservation is very low. We report here the crystal structures of human NRK1 in a binary complex with the reaction product nicotinamide mononucleotide (NMN) at 1.5 {angstrom} resolution and in a ternary complex with ADP and tiazofurin at 2.7 {angstrom} resolution. The active site is located in a groove between the central parallel {beta} sheet core and the LID and NMP-binding domains. The hydroxyl groups on the ribose of NR are recognized by Asp56 and Arg129, and Asp36 is the general base of the enzyme. Mutation of residues in the active site can abolish the catalytic activity of the enzyme, confirming the structural observations.

  1. The Crystal Structure of Human Argonaute2

    Energy Technology Data Exchange (ETDEWEB)

    Schirle, Nicole T.; MacRae, Ian J. (Scripps)

    2012-07-18

    Argonaute proteins form the functional core of the RNA-induced silencing complexes that mediate RNA silencing in eukaryotes. The 2.3 angstrom resolution crystal structure of human Argonaute2 (Ago2) reveals a bilobed molecule with a central cleft for binding guide and target RNAs. Nucleotides 2 to 6 of a heterogeneous mixture of guide RNAs are positioned in an A-form conformation for base pairing with target messenger RNAs. Between nucleotides 6 and 7, there is a kink that may function in microRNA target recognition or release of sliced RNA products. Tandem tryptophan-binding pockets in the PIWI domain define a likely interaction surface for recruitment of glycine-tryptophan-182 (GW182) or other tryptophan-rich cofactors. These results will enable structure-based approaches for harnessing the untapped therapeutic potential of RNA silencing in humans.

  2. Thermal Oxidation of Structured Silicon Dioxide

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Hansen, Ole; Jensen, Jørgen Arendt

    2014-01-01

    The topography of thermally oxidized, structured silicon dioxide is investigated through simulations, atomic force microscopy, and a proposed analytical model. A 357 nm thick oxide is structured by removing regions of the oxide in a masked etch with either reactive ion etching or hydrofluoric acid....... Subsequent thermal oxidation is performed in both dry and wet ambients in the temperature range 950◦C to 1100◦C growing a 205 ± 12 nm thick oxide in the etched mask windows. Lifting of the original oxide near the edge of the mask in the range 6 nm to 37 nm is seen with increased lifting for increasing...

  3. Thermal analysis of the vertical bridgman semiconductor crystal growth technique. Ph.D. Thesis

    Science.gov (United States)

    Jasinski, T. J.

    1982-01-01

    The quality of semiconductor crystals grown by the vertical Bridgman technique is strongly influenced by the axial and radial variations of temperature within the charge. The relationship between the thermal parameters of the vertical Bridgman system and the thermal behavior of the charge are examined. Thermal models are developed which are capable of producing results expressable in analytical form and which can be used without recourse to extensive computer work for the preliminary thermal design of vertical Bridgman crystal growth systems. These models include the effects of thermal coupling between the furnace and the charge, charge translation rate, charge diameter, thickness and thermal conductivity of the confining crucible, thermal conductivity change and liberation of latent heat at the growth interface, and infinite charge length. The hot and cold zone regions, considered to be at spatially uniform temperatures, are separated by a gradient control region which provides added thermal design flexibility for controlling the temperature variations near the growth interface.

  4. Thermal expansion behavior of A- and B-type amylose crystals in the low-temperature region.

    Science.gov (United States)

    Kobayashi, Kayoko; Kimura, Satoshi; Naito, Philip-Kunio; Togawa, Eiji; Wada, Masahisa

    2015-10-20

    The thermal expansion behaviors of A-type and B-type amylose crystals, which were prepared by recrystallization of short amylose chains synthesized by phosphorylase, were investigated using synchrotron X-ray powder diffraction between 100 and 300K. For both types of crystals, the room-temperature phase (RT phase), which is the usually observed phase, transitioned to a low-temperature phase (LT phase), on cooling. The phase transitions took place reversibly with rapid changes in the unit-cell parameters around 200-270K. The differences between the RT and LT phase were investigated using solid-state (13)C NMR spectroscopy, which revealed there were changes in molecular chain conformations. These results suggest that the phase transition of water molecules on the crystalline surfaces affects the thermal behavior and structure of polysaccharide crystals.

  5. Steady distribution structure of point defects near crystal-melt interface under pulling stop of CZ Si crystal

    Science.gov (United States)

    Abe, T.; Takahashi, T.; Shirai, K.

    2017-02-01

    In order to reveal a steady distribution structure of point defects of no growing Si on the solid-liquid interface, the crystals were grown at a high pulling rate, which Vs becomes predominant, and the pulling was suddenly stopped. After restoring the variations of the crystal by the pulling-stop, the crystals were then left in prolonged contact with the melt. Finally, the crystals were detached and rapidly cooled to freeze point defects and then a distribution of the point defects of the as-grown crystals was observed. As a result, a dislocation loop (DL) region, which is formed by the aggregation of interstitials (Is), was formed over the solid-liquid interface and was surrounded with a Vs-and-Is-free recombination region (Rc-region), although the entire crystals had been Vs rich in the beginning. It was also revealed that the crystal on the solid-liquid interface after the prolonged contact with the melt can partially have a Rc-region to be directly in contact with the melt, unlike a defect distribution of a solid-liquid interface that has been growing. This experimental result contradicts a hypothesis of Voronkov's diffusion model, which always assumes the equilibrium concentrations of Vs and Is as the boundary condition for distribution of point defects on the growth interface. The results were disscussed from a qualitative point of view of temperature distribution and thermal stress by the pulling-stop.

  6. Thermal Tomography of Asteroid Surface Structure

    Science.gov (United States)

    Harris, Alan W.; Drube, Line

    2016-12-01

    Knowledge of the surface thermal inertia of an asteroid can provide insight into its surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles (“kinetic impactors”) in planetary defense.

  7. Synthesis, Character and Crystal Structure of the Complex {Er(DMSO)7} PW12O40

    Institute of Scientific and Technical Information of China (English)

    HAN Qiu-Xia; ZHANG Da-Li; MA Jian-Ru; WANG Jing-Ping; NIU Jing-Yang

    2007-01-01

    The synthesis, X-ray crystal structure, thermal properties and electrochemistry of the new complex formulated as {Er(DMSO)7}PW12O40 are reported. The single-crystal X-ray analysis reveals that the crystal crystallizes in the monoclinic system, space group P21/c with a=11.767(2), b=14.909(3), c=34.905(7)(A), β=98.97(3)°, Mr=3591.33, V=6049(2) (A)3, Dc=3.944g/em3, Z=4, GOOF=1.098, F(000)=6340, R=0.0490 and wR=0.1202. Crystal structure analysis indicates that the Er(Ⅲ) is seven-coordinate with a distorted pentagonal bipyramid and combines to the anion [PW12O40]3- via static electric force.

  8. Thermal and structural analysis of Hermes

    Science.gov (United States)

    Petiau, C.

    1989-08-01

    After a brief recap of Hermes TPS and structure principles, we present the organization of thermal and structural analysis of the Hermes project, and we describe the way to resolve the problems of connections between calculations performed by the different Hermes partners. We describe in detail the interactions between the general model of TPS, used for global dimensioning of insulation, and refined thermal models giving an accurate temperature map inside details of "hot" and "cold" structures. The organization for structural analysis is based on a finite element general model which supports preliminary design, loads and vibration analyses. Boundary conditions for refined subpart analyses are cut to size, into the general model by a super element technique. This process involves the use by all partners of efficient computer codes, in the field of structural analysis and optimization integrated with CAD; for this Dassault proposes as a reference: the CATIA-ELFINI system.

  9. Structural Transitions in Cholesteric Liquid Crystal Droplets

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Ye; Bukusoglu, Emre; Martinez-Gonzalez, Jose A.; Rahimi, Mohammad; Roberts, Tyler F.; Zhang, Rui; Wang, Xiaoguang; Abbott, Nicholas L.; de Pablo, Juan J.

    2016-07-01

    Confinement of cholesteric liquid crystals (ChLC) into droplets leads to a delicate interplay between elasticity, chirality, and surface energy. In this work, we rely on a combination of theory and experiments to understand the rich morphological behavior that arises from that balance. More specifically, a systematic study of micrometer-sized ChLC droplets is presented as a function of chirality and surface energy (or anchoring). With increasing chirality, a continuous transition is observed from a twisted bipolar structure to a radial spherical structure, all within a narrow range of chirality. During such a transition, a bent structure is predicted by simulations and confirmed by experimental observations. Simulations are also able to capture the dynamics of the quenching process observed in experiments. Consistent with published work, it is found that nanoparticles are attracted to defect regions on the surface of the droplets. For weak anchoring conditions at the nanoparticle surface, ChLC droplets adopt a morphology similar to that of the equilibrium helical phase observed for ChLCs in the bulk. As the anchoring strength increases, a planar bipolar structure arises, followed by a morphological transition to a bent structure. The influence of chirality and surface interactions are discussed in the context of the potential use of ChLC droplets as stimuli-responsive materials for reporting molecular adsorbates.

  10. Synthesis and crystal structure of a trihydrate of dinuclear benzimidazole-2-pyridine-carboxylate-cadmium(II

    Directory of Open Access Journals (Sweden)

    Jia Jun Wang

    2009-12-01

    Full Text Available A new compound, [Cd2(C7H6N23(C6H4O2N4]•3H2O (1, has been prepared under mild hydrothermal conditions and structurally characterized by single crystal X-ray diffraction. The two cadmium(II ions are bridged by a carboxyl group from one 2-pyridinecarboxylate ligand. The thermal gravimetry (TG data indicate three steps of decomposition, and the final thermal decomposition product is CdO.

  11. Crystal structure of strontium dinickel iron orthophosphate

    Directory of Open Access Journals (Sweden)

    Said Ouaatta

    2015-10-01

    Full Text Available The title compound, SrNi2Fe(PO43, synthesized by solid-state reaction, crystallizes in an ordered variant of the α-CrPO4 structure. In the asymmetric unit, two O atoms are in general positions, whereas all others atoms are in special positions of the space group Imma: the Sr cation and one P atom occupy the Wyckoff position 4e (mm2, Fe is on 4b (2/m, Ni and the other P atom are on 8g (2, one O atom is on 8h (m and the other on 8i (m. The three-dimensional framework of the crystal structure is built up by [PO4] tetrahedra, [FeO6] octahedra and [Ni2O10] dimers of edge-sharing octahedra, linked through common corners or edges. This structure comprises two types of layers stacked alternately along the [100] direction. The first layer is formed by edge-sharing octahedra ([Ni2O10] dimer linked to [PO4] tetrahedra via common edges while the second layer is built up from a strontium row followed by infinite chains of alternating [PO4] tetrahedra and FeO6 octahedra sharing apices. The layers are held together through vertices of [PO4] tetrahedra and [FeO6] octahedra, leading to the appearance of two types of tunnels parallel to the a- and b-axis directions in which the Sr cations are located. Each Sr cation is surrounded by eight O atoms.

  12. Crystal structures of five 6-mercaptopurine derivatives

    Directory of Open Access Journals (Sweden)

    Lígia R. Gomes

    2016-03-01

    Full Text Available The crystal structures of five 6-mercaptopurine derivatives, viz. 2-[(9-acetyl-9H-purin-6-ylsulfanyl]-1-(3-methoxyphenylethan-1-one (1, C16H14N4O3S, 2-[(9-acetyl-9H-purin-6-ylsulfanyl]-1-(4-methoxyphenylethan-1-one (2, C16H14N4O3S, 2-[(9-acetyl-9H-purin-6-ylsulfanyl]-1-(4-chlorophenylethan-1-one (3, C15H11ClN4O2S, 2-[(9-acetyl-9H-purin-6-ylsulfanyl]-1-(4-bromophenylethan-1-one (4, C15H11BrN4O2S, and 1-(3-methoxyphenyl-2-[(9H-purin-6-ylsulfanyl]ethan-1-one (5, C14H12N4O2S. Compounds (2, (3 and (4 are isomorphous and accordingly their molecular and supramolecular structures are similar. An analysis of the dihedral angles between the purine and exocyclic phenyl rings show that the molecules of (1 and (5 are essentially planar but that in the case of the three isomorphous compounds (2, (3 and (4, these rings are twisted by a dihedral angle of approximately 38°. With the exception of (1 all molecules are linked by weak C—H...O hydrogen bonds in their crystals. There is π–π stacking in all compounds. A Cambridge Structural Database search revealed the existence of 11 deposited compounds containing the 1-phenyl-2-sulfanylethanone scaffold; of these, only eight have a cyclic ring as substituent, the majority of these being heterocycles.

  13. Crystal Structures of Respiratory Pathogen Neuraminidases

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, Y.; Parker, D; Ratner, A; Prince, A; Tong, L

    2009-01-01

    Currently there is pressing need to develop novel therapeutic agents for the treatment of infections by the human respiratory pathogens Pseudomonas aeruginosa and Streptococcus pneumoniae. The neuraminidases of these pathogens are important for host colonization in animal models of infection and are attractive targets for drug discovery. To aid in the development of inhibitors against these neuraminidases, we have determined the crystal structures of the P. aeruginosa enzyme NanPs and S. pneumoniae enzyme NanA at 1.6 and 1.7 {angstrom} resolution, respectively. In situ proteolysis with trypsin was essential for the crystallization of our recombinant NanA. The active site regions of the two enzymes are strikingly different. NanA contains a deep pocket that is similar to that in canonical neuraminidases, while the NanPs active site is much more open. The comparative studies suggest that NanPs may not be a classical neuraminidase, and may have distinct natural substrates and physiological functions. This work represents an important step in the development of drugs to prevent respiratory tract colonization by these two pathogens.

  14. Extraction and Crystal Structure of Karounidiol

    Institute of Scientific and Technical Information of China (English)

    巢志茂; 王诚

    2003-01-01

    The title compound of karounidiol (C30H48O2), a main active triterpene component of snakegourd seed, was isolated from unsaponifiable matter of the seed oil of Trichosanthes kirilowii Maxim., and characterized by X-ray diffraction analysis. It crystallizes in orthorhombic system, space group P212121 with C30H48O2·CH3OH·H2O (C31H54O4), a = 7.515(1), b = 14.407(1), c = 27.799(2) (A。), V = 3009.8(5)(A。)3, Z = 4, Dx = 1.087 g/cm3, Mr = 490.77, F(000) = 1088 and μ = 0.086 mm-1. The final R = 0.0840 and wR = 0.2289 for 2752 observed reflections (|F|2 ≥ 2σ|F|2). The molecular crystal structure of karounidiol shows relative stereochemistry of (3α,13α,14β, 20α)-3,29-dihydroxy-13-methyl-26-norolean-7,9(11)-diene. The molecule is composed of five six- membered rings with ring junctures of A/B trans, C/D trans and D/E cis.

  15. Crystal and molecular structure of aflatrem

    Directory of Open Access Journals (Sweden)

    Bruno N. Lenta

    2015-11-01

    Full Text Available The crystal structure of the title compound, C32H39NO4, confirms the absolute configuration of the seven chiral centres in the molecule. The molecule has a 1,1-dimethylprop-2-enyl substituent on the indole nucleus and this nucleus shares one edge with the five-membered ring which is, in turn, connected to a sequence of three edge-shared fused rings. The skeleton is completed by the 7,7-trimethyl-6,8-dioxabicyclo[3.2.1]oct-3-en-2-one group connected to the terminal cyclohexene ring. The two cyclohexane rings adopt chair and half-chair conformations, while in the dioxabicyclo[3.2.1]oct-3-en-2-one unit, the six-membered ring has a half-chair conformation. The indole system of the molecule exhibits a tilt of 2.02 (1° between its two rings. In the crystal, O—H...O hydrogen bonds connect molecules into chains along [010]. Weak N—H...π interactions connect these chains, forming sheets parallel to (10-1.

  16. The crystal structure Escherichia coli Spy.

    Science.gov (United States)

    Kwon, Eunju; Kim, Dong Young; Gross, Carol A; Gross, John D; Kim, Kyeong Kyu

    2010-11-01

    Escherichia coli spheroplast protein y (EcSpy) is a small periplasmic protein that is homologous with CpxP, an inhibitor of the extracytoplasmic stress response. Stress conditions such as spheroplast formation induce the expression of Spy via the Cpx or the Bae two-component systems in E. coli, though the function of Spy is unknown. Here, we report the crystal structure of EcSpy, which reveals a long kinked hairpin-like structure of four α-helices that form an antiparallel dimer. The dimer contains a curved oval shape with a highly positively charged concave surface that may function as a ligand binding site. Sequence analysis reveals that Spy is highly conserved over the Enterobacteriaceae family. Notably, three conserved regions that contain identical residues and two LTxxQ motifs are placed at the horizontal end of the dimer structure, stabilizing the overall fold. CpxP also contains the conserved sequence motifs and has a predicted secondary structure similar to Spy, suggesting that Spy and CpxP likely share the same fold.

  17. Crystal structure of zirconia by Rietveld refinement

    Institute of Scientific and Technical Information of China (English)

    王大宁; 郭永权; 梁开明; 陶琨

    1999-01-01

    The crystal structures and phase transformation of zirconia ceramics have been investigated by means of X-ray powder diffraction and Rietveld powder diffraction profile fitting technique. A structural transition from monoclinic to tetragonal occurs when Y2O3 and CeO2 are doped into zirconia. The space group of the tetragonal structure is P42/nmc, Z=2. The lattice parameters are α=0.362 6(5) nm, c=0.522 6(3)nm for CeO2 doped zirconia and α=0. 360 2(8)nm, c=0. 517 9(1)nm for Y2O3 doped zirconia, respectively. In each unit cell, there are two kinds of equivalent positions, i. e. 2b and 4d, which are occupied by Zr4+, M(M=Y3+, Ce4+) cations and O2- anions, respectively. The crystallographic correlation among the cubic, tetragonal and monoclinic structures of ZrO2 is discussed.

  18. 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.

  19. Three-dimensional self-assembled photonic crystals with high temperature stability for thermal emission modification

    Science.gov (United States)

    Arpin, Kevin A.; Losego, Mark D.; Cloud, Andrew N.; Ning, Hailong; Mallek, Justin; Sergeant, Nicholas P.; Zhu, Linxiao; Yu, Zongfu; Kalanyan, Berç; Parsons, Gregory N.; Girolami, Gregory S.; Abelson, John R.; Fan, Shanhui; Braun, Paul V.

    2013-10-01

    Selective thermal emission in a useful range of energies from a material operating at high temperatures is required for effective solar thermophotovoltaic energy conversion. Three-dimensional metallic photonic crystals can exhibit spectral emissivity that is modified compared with the emissivity of unstructured metals, resulting in an emission spectrum useful for solar thermophotovoltaics. However, retention of the three-dimensional mesostructure at high temperatures remains a significant challenge. Here we utilize self-assembled templates to fabricate high-quality tungsten photonic crystals that demonstrate unprecedented thermal stability up to at least 1,400 °C and modified thermal emission at solar thermophotovoltaic operating temperatures. We also obtain comparable thermal and optical results using a photonic crystal comprising a previously unstudied material, hafnium diboride, suggesting that refractory metallic ceramic materials are viable candidates for photonic crystal-based solar thermophotovoltaic devices and should be more extensively studied.

  20. Thermal-induced conformational changes in the product release area drive the enzymatic activity of xylanases 10B: Crystal structure, conformational stability and functional characterization of the xylanase 10B from Thermotoga petrophila RKU-1

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Camila Ramos; Meza, Andreia Navarro [Laboratorio Nacional de Biociencias (LNBio), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil); Hoffmam, Zaira Bruna; Silva, Junio Cota; Alvarez, Thabata Maria; Ruller, Roberto [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil); Giesel, Guilherme Menegon; Verli, Hugo [Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Squina, Fabio Marcio [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil); Prade, Rolf Alexander [Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK (United States); Murakami, Mario Tyago, E-mail: mario.murakami@lnbio.org.br [Laboratorio Nacional de Biociencias (LNBio), Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP (Brazil)

    2010-12-10

    Research highlights: {yields} The hyperthermostable xylanase 10B from Thermotoga petrophila RKU-1 produces exclusively xylobiose at the optimum temperature. {yields} Circular dichroism spectroscopy suggests a coupling effect of temperature-induced structural changes with its enzymatic behavior. {yields} Crystallographic and molecular dynamics studies indicate that conformational changes in the product release area modulate the enzyme action mode. -- Abstract: Endo-xylanases play a key role in the depolymerization of xylan and recently, they have attracted much attention owing to their potential applications on biofuels and paper industries. In this work, we have investigated the molecular basis for the action mode of xylanases 10B at high temperatures using biochemical, biophysical and crystallographic methods. The crystal structure of xylanase 10B from hyperthermophilic bacterium Thermotoga petrophila RKU-1 (TpXyl10B) has been solved in the native state and in complex with xylobiose. The complex crystal structure showed a classical binding mode shared among other xylanases, which encompasses the -1 and -2 subsites. Interestingly, TpXyl10B displayed a temperature-dependent action mode producing xylobiose and xylotriose at 20 {sup o}C, and exclusively xylobiose at 90 {sup o}C as assessed by capillary zone electrophoresis. Moreover, circular dichroism spectroscopy suggested a coupling effect of temperature-induced structural changes with this particular enzymatic behavior. Molecular dynamics simulations supported the CD analysis suggesting that an open conformational state adopted by the catalytic loop (Trp297-Lys326) provokes significant modifications in the product release area (+1,+2 and +3 subsites), which drives the enzymatic activity to the specific release of xylobiose at high temperatures.

  1. A New Copper(I) Complex Based on 4-amino-3,5-bis(3-pyridyl)-1,2,4-triazole: Synthesis, Crystal Structure, Theoretical Study, Thermal Behavior and Luminescence

    Indian Academy of Sciences (India)

    CHEN AI-HUA; MENG SU-CI; ZHOU KAI; WANG CONG-CONG; ZHAO WEI; WANG AI-JIAN; QIAN JUN

    2017-02-01

    The synthesis, characterization and structure of a 1D coordination polymer {[CuBr(3-abpt)]·2DMSO}n (1) (3-abpt = 4-amino-3,5-bis(3-pyridyl)-1,2,4-triazole) is described. X-ray structural analyses reveal that 1 exhibits a 1D ladder-like chain structure and each copper(I) center in 1 displays a distorted tetrahedral coordination geometry {CuN3Br}. Density functional theory and time-dependent density functional theory calculations at the B3LYP/LanL2DZf+6-31G* level were performed on complex 1 to rationalize its experimental absorption spectra. The luminescent property and thermal behavior of the complex were also investigated.

  2. Thermal Tomography of Asteroid Surface Structure

    CERN Document Server

    Harris, Alan

    2016-01-01

    Knowledge of the surface thermal inertia of an asteroid can provide insight into surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Eviden...

  3. The crystal structure of {gamma}-AlD{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Brinks, H.W. [Institute for Energy Technology, P.O. Box 40, Kjeller N-2027 (Norway); Brown, C. [Department of Chemistry, University of Hawaii, Honolulu, HI 96822 (United States); Jensen, C.M. [Department of Chemistry, University of Hawaii, Honolulu, HI 96822 (United States); Graetz, J. [Department of Energy Sciences and Technologies, Brookhaven National Laboratory, Upton, NY 11973 (United States); Reilly, J.J. [Department of Energy Sciences and Technologies, Brookhaven National Laboratory, Upton, NY 11973 (United States); Hauback, B.C. [Institute for Energy Technology, P.O. Box 40, Kjeller N-2027 (Norway)]. E-mail: bjorn.hauback@ife.no

    2007-08-30

    {gamma}-AlD{sub 3} was synthesized from LiAlD{sub 4} and AlCl{sub 3} via thermal decomposition of aluminum hydride etherate in presence of excess LiAlD{sub 4}. {gamma}-AlD{sub 3} was determined by powder neutron diffraction and synchrotron X-ray diffraction to crystallize in the space group Pnnm. The orthorhombic structure has unit-cell dimensions a = 7.3360(3) A, b = 5.3672(2) A and c = 5.7562(1) A, and it consists of both corner- and edge-sharing AlD{sub 6} octahedra where each hydrogen is shared between two octahedra. The average Al-D distances in octahedra with edge-sharing is 1.706 A and in the octahedra with only corner-sharing 1.719 A.

  4. Synthesis, crystal structure, and spectroscopic characterization supported by DFT calculations of organoarsenic compound

    Science.gov (United States)

    Ennaceur, Nasreddine; Henchiri, Rokaya; Jalel, Boutheina; Cordier, Marie; Ledoux-Rak, Isabelle; Elaloui, Elimame

    2017-09-01

    A new semi-organic hydrogen bonding complex salt of 2-ammonium phenylarsonic acid and nitric acid has been synthesized, thus successfully growing good quality single crystals by means of slow solvent evaporation technique at ambient temperature. The 1H and 13C NMR spectra were recorded to establish the molecular structure. The conducted single crystal XRD analysis has shown that the title salt is crystalized in orthorhombic crystal system with centrosymmetric Pbcm space group. The structure consists of infinite parallel two-dimensional planes built of (C6H6NH3AsO3)+ organic cation and NO3- inorganic anions connected by hydrogen bonds and π-π interactions giving birth a three-dimensional network. The performed TG/DSC thermal analysis has established the thermal stability of the crystal. The optimized structural parameters and vibrational frequencies (the experimental and theoretical vibrational frequencies) were assigned and compared by the Density Functional Theory (DFT) using the Gaussian method (DFT/B3LYP). Good consistency results were found between the calculated and the experimental crystal structure and FT-IR spectra.

  5. Crystal structure of phenyl N-(4-nitrophenylcarbamate

    Directory of Open Access Journals (Sweden)

    Y. AaminaNaaz

    2015-12-01

    Full Text Available The asymmetric unit of the title compound, C13H10N2O4, contains two independent molecules (A and B. The dihedral angle between the aromatic rings is 48.18 (14° in molecule A and 45.81 (14° in molecule B. The mean plane of the carbamate N—C(=O—O group is twisted slightly from the attached benzene and phenyl rings, making respective dihedral angles of 12.97 (13 and 60.93 (14° in A, and 23.11 (14 and 59.10 (14° in B. In the crystal, A and B molecules are arranged alternately through N—H...O hydrogen bonds and C—H...π interactions, forming chains along the a axis. The chains are further linked by C—H...O hydrogen bonds into a double-chain structure.

  6. New Tricks of the Trade for Crystal Structure Refinement.

    Science.gov (United States)

    Li, Jinjin; Abramov, Yuriy A; Doherty, Michael F

    2017-07-26

    Accurate crystal structures and their experimental uncertainties, determined by X-ray diffraction/neutron diffraction techniques, are vital for crystal engineering studies, such as polymorph stability and crystal morphology calculations. Because of differences in crystal growth and data measurement conditions, crystallographic databases often contain multiple entries of varying quality of the same compound. The choice of the most reliable and best quality crystal structure from many very similar structures remains an unresolved problem, especially for nonexperts. In addition, while crystallographers can make use of some professional software (i.e., Materials Studio) for structure refinement, noncrystallographers may not have access to it. In the present paper, we propose a simple method to study the sensitivity of the crystal lattice energy to changes in the structural parameters, which creates a diagnostic tool to test the quality of crystal structure files and to improve the low-quality structures based on lattice energy distribution. Thus, noncrystallographers could take the proposed idea and program/optimize crystal structure by themselves. They can have their in-house program to determine the reliability of the selected crystal data and then use the best quality data or carry out structural optimization for low-quality data. The proposed method will benefit a broad cross-section of scientific researchers, especially those in solid-state and physical chemistry.

  7. Crystal structure and thermal behavior of Cs{sub 2}[B{sub 4}O{sub 5}(OH){sub 4}]3H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Touboul, M.; Penin, N. [UPRES, Amiens (France). Lab. de Reactivite et de Chimie des Solides; Nowogrocki, G. [ENSC Lille, Villeneuve d`Ascq (France). Lab. de Cristallochimie et Physicochimie du Solide

    1999-03-01

    The crystal structure of synthetic Cs{sub 2}[B{sub 4}O{sub 5}(OH){sub 4}]3H{sub 2}O was determined from single-crystal X-ray diffraction data. The compound is monoclinic, space group P2{sub 1}/c; the unit cell parameters are a = 8.424(2) {angstrom}, b = 11.378(3) {angstrom}, c = 13.160(5) {angstrom}, {beta} = 92.06(3){degree}; Z = 4. The crystal structure was solved from 6355 reflections until R = 0.029; it contains isolated [B{sub 4}O{sub 5}(OH){sub 4}]{sup 2{minus}} polyanions separated by free water molecules and Cs{sup +} ions. Although its formula is the same as that of the tincalconite Na{sub 2}[B{sub 4}O{sub 5}(OH){sub 4}]3H{sub 2}O, Cs{sub 2}[B{sub 4}O{sub 5}(OH){sub 4}]3H{sub 2}O structure is close to that of synthetic K{sub 2}[B{sub 4}O{sub 5}(OH){sub 4}]2H{sub 2}O which contains only two isolated water molecules. In the cesium and the potassium borates, the [B{sub 4}O{sub 5}(OH){sub 4}]{sup 2{minus}} anions have not a two-fold axis as in the tincalconite; the shorthand notations of these two kinds of anions shall be noted as: 4: 2{Delta} + 2T in the first two borates and 4:({Delta} + T){sub 2} in the tincalconite, {Delta} and T being triangular and tetrahedral borons, respectively. Cs{sub 2}[B{sub 4}O{sub 5}(OH){sub 4}]3H{sub 2}O indexed X-ray powder diffraction pattern is given. The dehydration of this borate occurs in two close steps and leads to an amorphous phase; this process is well explained considering the structure and especially the change in the Cs{sup +} coordination during the heating.

  8. Stability of orientationally disordered crystal structures of colloidal hard dumbbells.

    Science.gov (United States)

    Marechal, Matthieu; Dijkstra, Marjolein

    2008-06-01

    We study the stability of orientationally disordered crystal phases in a suspension of colloidal hard dumbbells using Monte Carlo simulations. For dumbbell bond length L/sigmafcc structure for a large part of the stable plastic crystal regime. In addition, we study the stability of an orientationally disordered aperiodic crystal structure in which the spheres of the dumbbells are on a random-hexagonal-close-packed lattice, and the dumbbells are formed by taking random pairs of neighboring spheres. Using free-energy calculations, we determine the fluid-aperiodic crystal and periodic-aperiodic crystal coexistence regions for L/sigma>0.88 .

  9. Affine structures and a tableau model for E_6 crystals

    CERN Document Server

    Jones, Brant

    2009-01-01

    We provide the unique affine crystal structure for type E_6^{(1)} Kirillov-Reshetikhin crystals corresponding to the multiples of fundamental weights s Lambda_1, s Lambda_2, and s Lambda_6 for all s \\geq 1 (in Bourbaki's labeling of the Dynkin nodes, where 2 is the adjoint node). Our methods introduce a generalized tableaux model for classical highest weight crystals of type E and use the order three automorphism of the affine E_6^{(1)} Dynkin diagram. In addition, we provide a conjecture for the affine crystal structure of type E_7^{(1)} Kirillov-Reshetikhin crystals corresponding to the adjoint node.

  10. Growth, optical, thermal and mechanical characterization of an organic crystal: Brucinium 5-sulfosalicylate trihydrate

    Indian Academy of Sciences (India)

    K Gayathri; P Krishnan; P R Rajkumar; G Anbalagan

    2014-12-01

    Single crystals of Brucinium 5-sulfosalicylate trihydrate (B5ST) were grown from ethanol–water (1:1) mixed solvent by the slow solvent evaporation method. X-ray powder diffraction analysis reveals that the crystal belongs to orthorhombic system with space group 212121. The various reflections were indexed and the lattice parameters were calculated. Photoluminescence (PL) shows peaks corresponding to protonation of the amino group. The optical absorption spectrum shows that the crystal has 90% transmittance in the visible region with a lower cut-off wavelength of 312 nm. Thermal analysis performed on the grown crystal indicates the thermal stability of the crystal and various thermodynamical parameters were calculated from the thermogravimetry (TG) data. The mechanical properties like Vickers microhardness number (v), stiffness constant (11) and yield strength (v) of the crystal were estimated by Vickers hardness test.

  11. Isomorph invariance of the structure and dynamics of classical crystals

    DEFF Research Database (Denmark)

    Albrechtsen, Dan; Olsen, Andreas Elmerdahl; Pedersen, Ulf Rørbæk

    2014-01-01

    of a defective fcc crystal is also shown to be isomorph invariant. In contrast, a NaCl crystal model does not exhibit isomorph invariances. Other systems simulated, though in less detail, are the Wahnström binary Lennard-Jones crystal with the MgZn2 Laves crystal structure, monatomic fcc crystals of particles......This paper shows by computer simulations that some crystalline systems have curves in their thermodynamic phase diagrams, so-called isomorphs, along which structure and dynamics in reduced units are invariant to a good approximation. The crystals are studied in a classical-mechanical framework......, which is generally a good description except significantly below melting. The existence of isomorphs for crystals is validated by simulations of particles interacting via the Lennard-Jones pair potential arranged into a face-centered cubic (fcc) crystalline structure; the slow vacancy-jump dynamics...

  12. An unsymmetrical porphyrin and its metal complexes: synthesis, spectroscopy, thermal analysis and liquid crystal properties

    Directory of Open Access Journals (Sweden)

    CHANGFU ZHUANG

    2009-09-01

    Full Text Available The synthesis and characterization of a new unsymmetrical porphyrin liquid crystal, 5-(4-stearoyloxyphenylphenyl-10,15,20-triphenylporphyrin (SPTPPH2 and its transition metal complexes (SPTPPM, M(II = Zn, Fe, Co, Ni, Cu or Mn are reported. Their structure and properties were studied by elemental analysis, and UV–Vis, IR, mass and 1H-HMR spectroscopy. Their luminescent properties were studied by excitation and emission spectroscopy. The quantum yields of the S1 ® S0 fluorescence were measured at room temperature. According to thermal studies, the complexes have a higher thermal stability (no decomposition until 200 °C. Differential scanning calorimetry (DSC data and an optical textural photograph, obtained using a polarizing microscope (POM, indicate that the porphyrin ligand had liquid crystalline character and that it exhibited more than one mesophase and a low-lying phase transition temperature, with transition temperatures of 19.3 and 79.4 °C; the temperature range of the liquid crystal (LC phase of the ligand was 70.1 °C.

  13. Revisiting the blind tests in crystal structure prediction: accurate energy ranking of molecular crystals.

    Science.gov (United States)

    Asmadi, Aldi; Neumann, Marcus A; Kendrick, John; Girard, Pascale; Perrin, Marc-Antoine; Leusen, Frank J J

    2009-12-24

    In the 2007 blind test of crystal structure prediction hosted by the Cambridge Crystallographic Data Centre (CCDC), a hybrid DFT/MM method correctly ranked each of the four experimental structures as having the lowest lattice energy of all the crystal structures predicted for each molecule. The work presented here further validates this hybrid method by optimizing the crystal structures (experimental and submitted) of the first three CCDC blind tests held in 1999, 2001, and 2004. Except for the crystal structures of compound IX, all structures were reminimized and ranked according to their lattice energies. The hybrid method computes the lattice energy of a crystal structure as the sum of the DFT total energy and a van der Waals (dispersion) energy correction. Considering all four blind tests, the crystal structure with the lowest lattice energy corresponds to the experimentally observed structure for 12 out of 14 molecules. Moreover, good geometrical agreement is observed between the structures determined by the hybrid method and those measured experimentally. In comparison with the correct submissions made by the blind test participants, all hybrid optimized crystal structures (apart from compound II) have the smallest calculated root mean squared deviations from the experimentally observed structures. It is predicted that a new polymorph of compound V exists under pressure.

  14. Atomic structure and crystallization processes of amorphous (Co,Ni)–P metallic alloy

    Energy Technology Data Exchange (ETDEWEB)

    Modin, Evgeny B., E-mail: modin.eb@dvfu.ru [Far Eastern Federal University, Shukhanova 8, Vladivostok 690950 (Russian Federation); Pustovalov, Evgeny V.; Fedorets, Aleksander N.; Dubinets, Aleksander V.; Grudin, Boris N.; Plotnikov, Vladimir S. [Far Eastern Federal University, Shukhanova 8, Vladivostok 690950 (Russian Federation); Grabchikov, Sergey S. [Scientific and Practical Centre of Material Science, Belarus National Academy of Sciences, P. Brovki 19, Minsk 220072 (Belarus)

    2015-08-25

    Highlights: • The CoP–CoNiP amorphous alloys were studied by the Cs-corrected high resolution transmission electron microscopy. • In situ heating experiments showed that crystallization starts at 200–250 °C on the network frame and cell boundaries. • Crystal growth occurs at the free surface, then the remaining material in the volume is crystallized. • Adding nickel to the CoP alloy leads to higher thermal stability. • At the beginning of crystallization there are high diffusion coefficients, 1.2–2.4 ∗ 10{sup −18} m{sup 2}/s at 250 °C. - Abstract: This work concerns the in situ investigation of the atomic structure of (Co,Ni)–P alloys during relaxation and crystallization by high resolution transmission electron microscopy. The CoP–CoNiP alloys, in the initial state, have a hierarchical network-like disordered structure. Crystallization starts at 200–250 °C on the network frame and cell boundaries. In the early stages, crystal growth occurs at the free surface, then the remaining material in the volume is crystallized. The diffusion coefficient at the start of crystallization is 1.2–2.4 × 10{sup −18} m{sup 2}/s at 250 °C and we assume that the high diffusion speed is due to surface diffusion.

  15. Effective group index of refraction in non-thermal plasma photonic crystals

    Science.gov (United States)

    Mousavi, A.; Sadegzadeh, S.

    2015-11-01

    Plasma photonic crystals (PPCs) are periodic arrays that consist of alternate layers of micro-plasma and dielectric. These structures are used to control the propagation of electromagnetic waves. This paper presents a survey of research on the effect of non-thermal plasma with bi-Maxwellian distribution function on one dimensional PPC. A plasma with temperature anisotropy is not in thermodynamic equilibrium and can be described by the bi-Maxwellian distribution function. By using Kronig-Penny's model, the dispersion relation of electromagnetic modes in one dimensional non-thermal PPC (NPPC) is derived. The band structure, group velocity vg, and effective group index of refraction neff(g) of such NPPC structure with TeO2 as the material of dielectric layers have been studied. The concept of negative group velocity and negative neff(g), which indicates an anomalous behaviour of the PPCs, are also observed in the NPPC structures. Our numerical results provide confirmatory evidence that unlike PPCs there are finite group velocity and non-zero effective group indexes of refraction in photonic band gaps (PBGs) that lie in certain ranges of normalized frequency. In other words, inside the PBGs of NPPCs, neff(g) becomes non-zero and photons travel with a finite group velocity. In this special case, this velocity varies alternately between 20c and negative values of the order 103c (c is the speed of light in vacuum).

  16. Some Lower Valence Vanadium Fluorides: Their Crystal Distortions, Domain Structures, Modulated Structures, Ferrimagnetism, and Composition Dependence.

    Science.gov (United States)

    Hong, Y. S.; And Others

    1980-01-01

    Describes some contemporary concepts unique to the structure of advanced solids, i.e., their crystal distortions, domain structures, modulated structures, ferrimagnetism, and composition dependence. (Author/CS)

  17. Thermally induced crystallization kinetics of uncrosslinked and unfilled synthetic cis-1,4-polyisoprene rubber monitored by shear rheological tests

    Science.gov (United States)

    Yang, Wei; Hong, Daesun; Kim, Hyungsu; Kim, Byungsoo; Chang, Wenji V.

    2016-11-01

    This study demonstrates the unique capability of a shear rotational rheometer for studying the thermally induced crystallization (TIC) of uncrosslinked and unfilled cis-1,4-polyisoprene rubber (IR). At temperatures below -15°C, a crystallization phenomenon (TIC) occurred in a quasi-unstrained IR specimen. Such a distinguished phenomenon was determined from the steady and sharp changes of both tanδ and the modulus. The changing ratio of those parameters with time characterizes the crystallization rate, on which the effects of the compressive force magnitude, testing repeat, and temperature are studied. The crystallization rate was shown to depend less on the magnitude of normal force, but depended largely on the specimen's previous testing history. A specimen not fully recovered from the previous crystallized memory showed a faster rate than before. More cooling to -25°C increased the crystallization rate, but the slow crystallization helped increase the final crystallinity. The crystallization rate was further interpreted by the Avrami equation to propose the crystal structure, whose morphological feature was shown in agreement with the reported TEM and X-ray results. However, our study found a thermo-mechanically aged specimen showed a very different rheological behavior at the late stage of crystallization suggesting the crystalline metamorphosis. But this unexpected behavior turned out to be unrecoverable indicating a property failure due to material aging more plausibly. All these findings were successfully monitored by the rheometer. It is expected the well-organized rheometric measurements can sufficiently supplement some instrumental limitations of the traditional crystallization monitoring analyzers on soft materials.

  18. CRYSTALLIZATION KINETICS OF GLASS-CERAMICS BY DIFFERENTIAL THERMAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    A. NOZAD

    2011-06-01

    Full Text Available The crystallization behavior of fluorphlogopite, a glass-ceramic in the MgO–SiO2–Al2O3–K2O–B2O3–F system, was studied by substitution of Li2O for K2O in the glass composition. DTA, XRD and SEM were used for the study of crystallization behavior, formed phases and microstructure of the resulting glass-ceramics. Crystallization kinetics of the glass was investigated under non-isothermal conditions, using the formal theory of transformations for heterogeneous nucleation. The crystallization results were analyzed, and both the activation energy of crystallization process as well as the crystallization mechanism were characterized. Calculated kinetic parameters indicated that the appropriate crystallization mechanism was bulk crystallization for base glass and the sample with addition of Li2O. Non-isothermal DTA experiments showed that the crystallization activation energies of base glasses was in the range of 234-246 KJ/mol and in the samples with addition of Li2O was changed to the range of 317-322 KJ/mol.

  19. Reconciling thermal and structural data from the polymorphic transitions of malonamide

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Eugene Y. [TransForm Pharmaceuticals, 29 Hartwell Avenue, Lexington, MA 02421 (United States)], E-mail: echeung@its.jnj.com; Peterson, Matthew L. [TransForm Pharmaceuticals, 29 Hartwell Avenue, Lexington, MA 02421 (United States)

    2009-01-15

    Although screening for organic polymorphs has become a hot topic in recent years, polymorph screens continue to be largely based on solution crystallization. Other routes to different crystal forms, such as grinding, annealing, and melt crystallization can also be used to look for polymorphs when chemical stability allows. Thermal analysis is often the first method for identifying polymorphic transitions in solids. However, reconciling the thermal data with the structural data is rarely straightforward without a single crystal X-ray structure. By using differential scanning calorimetry, infrared spectroscopy, and powder X-ray diffraction, the polymorphic transitions of malonamide have now been studied, and two solid state pathways, solid state grinding and annealing, are verified to independently yield the tetragonal polymorph of malonamide from the monoclinic form. In addition, melt recrystallization yields a third polymorph, which has now been confirmed to be the orthorhombic polymorph.

  20. Mitigation method of thermal transient stress by a total analysis of thermal hydraulic and structural phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Kasahara, Naoto [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center; Jinbo, Masakazu [Toshiba Co., Tokyo (Japan); Hosogai, Hiromi [Joyo Industry Co., Ltd., Tokai, Ibaraki (Japan)

    2002-09-01

    This study proposes a mitigation method of thermal transient loads in fast reactor components by utilizing relationships among plant system parameters and resulting thermal stresses. Conventional design procedure against thermal transient loads has two independent steps: thermal hydraulic analysis to determine conservative thermal transient conditions considering variation of the system parameters and structural analysis to check structural integrity under given conditions. On the other hand, a total analysis procedure of thermal hydraulic and structural phenomena can grasp the relationship among system parameters and thermal stresses. It enables the mitigation of thermal transient loads by adjusting system parameters. (author)

  1. Thermally induced crystallization in NbO2 thin films

    Science.gov (United States)

    Zhang, Jiaming; Norris, Kate J.; Gibson, Gary; Zhao, Dongxue; Samuels, Katy; Zhang, Minxian Max; Yang, J. Joshua; Park, Joonsuk; Sinclair, Robert; Jeon, Yoocharn; Li, Zhiyong; Williams, R. Stanley

    2016-09-01

    Niobium dioxide can exhibit negative differential resistance (NDR) in metal-insulator-metal (MIM) devices, which has recently attracted significant interest for its potential applications as a highly non-linear selector element in emerging nonvolatile memory (NVM) and as a locally-active element in neuromorphic circuits. In order to further understand the processing of this material system, we studied the effect of thermal annealing on a 15 nm thick NbO2 thin film sandwiched inside a nanoscale MIM device and compared it with 180 nm thick blanket NbOx (x = 2 and 2.5) films deposited on a silicon dioxide surface as references. A systematic transmission electron microscope (TEM) study revealed a similar structural transition from amorphous to a distorted rutile structure in both cases, with a transition temperature of 700 °C for the NbO2 inside the MIM device and a slightly higher transition temperature of 750 °C for the reference NbO2 film. Quantitative composition analysis from electron energy loss spectroscopy (EELS) showed the stoichiometry of the nominal 15 nm NbO2 layer in the as-fabricated MIM device deviated from the target 1:2 ratio because of an interaction with the electrode materials, which was more prominent at elevated annealing temperature.

  2. Thermally induced crystallization in NbO2 thin films

    Science.gov (United States)

    Zhang, Jiaming; Norris, Kate J.; Gibson, Gary; Zhao, Dongxue; Samuels, Katy; Zhang, Minxian Max; Yang, J. Joshua; Park, Joonsuk; Sinclair, Robert; Jeon, Yoocharn; Li, Zhiyong; Williams, R. Stanley

    2016-01-01

    Niobium dioxide can exhibit negative differential resistance (NDR) in metal-insulator-metal (MIM) devices, which has recently attracted significant interest for its potential applications as a highly non-linear selector element in emerging nonvolatile memory (NVM) and as a locally-active element in neuromorphic circuits. In order to further understand the processing of this material system, we studied the effect of thermal annealing on a 15 nm thick NbO2 thin film sandwiched inside a nanoscale MIM device and compared it with 180 nm thick blanket NbOx (x = 2 and 2.5) films deposited on a silicon dioxide surface as references. A systematic transmission electron microscope (TEM) study revealed a similar structural transition from amorphous to a distorted rutile structure in both cases, with a transition temperature of 700 °C for the NbO2 inside the MIM device and a slightly higher transition temperature of 750 °C for the reference NbO2 film. Quantitative composition analysis from electron energy loss spectroscopy (EELS) showed the stoichiometry of the nominal 15 nm NbO2 layer in the as-fabricated MIM device deviated from the target 1:2 ratio because of an interaction with the electrode materials, which was more prominent at elevated annealing temperature. PMID:27682633

  3. Photoluminescence polarization anisotropy for studying long-range structural ordering within semiconductor multi-atomic alloys and organic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Prutskij, T.; Percino, J. [Instituto de Ciencias, BUAP, Privada 17 Norte, No 3417, col. San Miguel Huyeotlipan, 72050, Puebla, Pue. (Mexico); Orlova, T. [Department of Chemical and Biochemical Engineering, University of Notre Dame, Notre Dame, IN (United States); Vavilova, L. [Ioffe Physical-Technical Institute, 26 Polytekhnicheskaya, St Petersburg 194021, Russian Federation (Russian Federation)

    2013-12-04

    Long-range structural ordering within multi-component semiconductor alloys and organic crystals leads to significant optical anisotropy and, in particular, to anisotropy of the photoluminescence (PL) emission. The PL emission of ternary and quaternary semiconductor alloys is polarized if there is some amount of the atomic ordering within the crystal structure. We analyze the polarization of the PL emission from the quaternary GaInAsP semiconductor alloy grown by Liquid Phase Epitaxy (LPE) and conclude that it could be caused by low degree atomic ordering within the crystal structure together with the thermal biaxial strain due to difference between the thermal expansion coefficients of the layer and the substrate. We also study the state of polarization of the PL from organic crystals in order to identify different features of the crystal PL spectrum.

  4. Thermal tuning of a silicon photonic crystal cavity infilled with an elastomer

    NARCIS (Netherlands)

    Erdamar, A.K.; Van Leest, M.M.; Picken, S.J.; Caro. J.

    2011-01-01

    Thermal tuning of the transmission of an elastomer infilled photonic crystal cavity is studied. An elastomer has a thermal expansion-induced negative thermo-optic coefficient that leads to a strong decrease of the refractive index upon heating. This property makes elastomer highly suitable for therm

  5. Reducing Thermal Effect in End-Diode-Pumped Laser Crystal by Using a Novel Resonator

    Institute of Scientific and Technical Information of China (English)

    YAO Ai-Yun; HOU Wei; LI Hui-Qing; BI Yong; LIN Xue-Chun; GENG Ai-Cong; KONG Yu-Peng; CUI Da-Fu; XU Zu-Yan

    2005-01-01

    @@ We report a new way, i.e. double-end-pumping, to extend the stability range of a laser resonator, in advantage of making the thermal loading be effectively divided between the ends of the laser crystal to reduce the thermal effect, thus to extend the stability range.

  6. 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.

  7. Thermal expansion of YBa2Cu3O7 single crystals

    Science.gov (United States)

    Aleksandrov, I. V.; Zibrov, I. P.; Stishov, S. M.

    1990-09-01

    The thermal expansion of a YBa2Cu3O7 single crystal was investigated by X-ray diffraction analysis at temperatures from 4 to 180 K. During the experiment, the crystal was glued to a beryllium plate coupled with a copper block inside the vacuum chamber of a helium cryostat. The temperature of the specimen was stabilized to within 0.01 K. The temperature was measured by using a platinum resistance thermometer. It is shown that the crystal is characterized by an anomalous behavior of the thermal expansion coefficient in the direction parallel to the Cu-O chains.

  8. EXTERNAL ACTION EFFECT ON THE STRUCTURE OF THE LIQUID PHASE, THE CRYSTALLIZATION PROCESS, STRUCTURE FORMATION OF COPPER

    Directory of Open Access Journals (Sweden)

    Mr. Eduard A. Dmitriev

    2016-09-01

    Full Text Available The paper presents the research results of a fluid phase overheating and alloying effect on cuprum mechanical characteristics. Careful analysis of poly-thermal cross-sections of electro-resistance proved that in order to obtain the maximum values of cuprum mechanical properties, it should be overheated 30 °С above the temperature threshold of abnormal electro-resistance change of a fluid phase (1320 °С. The paper presents the research results of the influence of thermal and thermo-high-speed treatment of cuprum melting on its structure, crystallization and structure formation processes. Regularities of structure change, crystallization parameters and structure formation depending on overheating and cooling rate of the melt are stated.

  9. Polymorphic crystal structures of an all-AT DNA dodecamer.

    Science.gov (United States)

    Acosta-Reyes, Francisco J; Subirana, Juan A; Pous, Joan; Sánchez-Giraldo, Raquel; Condom, Núria; Baldini, Roberto; Malinina, Lucy; Campos, J Lourdes

    2015-03-01

    In this work, we explore the influence of different solvents and ions on the crystallization behavior of an all-AT dodecamer d(AATAAATTTATT)2 In all cases, the oligonucleotides are found as continuous columns of stacked duplexes. The spatial organization of such columns is variable; consequently we have obtained seven different crystal forms. The duplexes can be made to crystallize in either parallel or crossed columns. Such versatility in the formation of a variety of crystal forms is characteristic for this sequence. It had not been previously reported for any other sequence. In all cases, the oligonucleotide duplexes have been found to crystallize in the B form. The crystallization conditions determine the organization of the crystal, although no clear local interactions have been detected. Mg(2+) and Ni(2+) can be used in order to obtain compact crossed structures. DNA-DNA interactions in the crystals of our all-AT duplexes present crossovers which are different from those previously reported for mixed sequence oligonucleotides. Our results demonstrate that changes in the ionic atmosphere and the crystallization solvent have a strong influence on the DNA-DNA interactions. Similar ionic changes will certainly influence the biological activity of DNA. Modulation of the crystal structure by ions should also be explored in DNA crystal engineering. Liquid crystals with a peculiar macroscopic shape have also been observed.

  10. Crystallization and Structure Determination of Superantigens and Immune Receptor Complexes.

    Science.gov (United States)

    Rödström, Karin E J; Lindkvist-Petersson, Karin

    2016-01-01

    Structure determination of superantigens and the complexes they form with immune receptors have over the years provided insight in their modes of action. This technique requires growing large and highly ordered crystals of the superantigen or receptor-superantigen complex, followed by exposure to X-ray radiation and data collection. Here, we describe methods for crystallizing superantigens and superantigen-receptor complexes using the vapor diffusion technique, how the crystals may be optimized, and lastly data collection and structure determination.

  11. Spectral, mechanical, thermal, optical and solid state parameters, of metal-organic bis(hydrogenmaleate)-CO(II) tetrahydrate crystal

    Science.gov (United States)

    Chandran, Senthilkumar; Jagan, R.; Paulraj, Rajesh; Ramasamy, P.

    2015-10-01

    Metal-organic bis(hydrogenmaleate)-Co(II) tetrahydrate single crystals have been grown by slow evaporation solution growth technique at room temperature. The crystal structure and the unit cell parameters were analyzed from the X-ray diffraction studies. Single-crystal X-ray diffraction analyses reveal that the grown crystal belongs to triclinic system with the space group P-1. Functional groups in bis(hydrogenmaleate)-Co(II) tetrahydrate were identified by Fourier transform infrared spectral analysis. The peak observed at 663 cm-1 is assigned to the (Co-O) stretching vibrations. The optical transmission of the crystal was studied by UV-vis-NIR spectral analysis. The photoluminescence emission studies were carried out for the title compound in a wide wavelength range between 350 nm and 550 nm at 303 K. Mechanical strength was tested by Vickers microhardness test. The laser damage threshold value has been determined using Nd:YAG laser operating at 1064 nm. At various frequencies and temperatures the dielectric behavior of the material was investigated. Solid state parameters such as plasma energy, Penn gap, Fermi energy and electronic polarizability were evaluated. Photoconductivity measurements were carried out for the grown crystal in the presence of DC electric field at room temperature. Thermal stability and decomposition of the crystal were studied by TG-DTA. The weight loss of the title compound occurs in different steps.

  12. Spectroscopic and thermal characterizations of Yb:LaF3 single crystal

    Science.gov (United States)

    Hong, Jiaqi; Zhang, Lianhan; Hang, Yin; Xu, Min

    2016-10-01

    A Yb3+ doped LaF3 laser crystal was detailed investigated by both spectroscopic and thermal measurements. A peak absorption at 974 nm with FWHM broader than 60 nm makes the crystal suitable to InGaAs LDs. Fluorescence spectrum and calculated spectroscopic parameters show potential of Yb:LaF3 crystal to laser operations around 1009 nm. A relatively long fluorescence lifetime of 2.92 ms was detected for Yb3+:2F5/2 manifold. The thermal diffusivity and specific heat capacity in the range of 300-575 K were studied to calculate the thermal conductivity of Yb:LaF3. The results indicate that the Yb:LaF3 crystal is a good candidate for diode-pumped ∼1 μm solid-state laser applications.

  13. Crystal structure refinement a crystallographers guide to SHELXL

    CERN Document Server

    2006-01-01

    A crystallographers guide to SHELXL, covering various aspects of practical crystal structure refinement, from the treatment of hydrogen atoms to the assignment of atom types, and more. After an introduction to SHELXL, a brief survey of crystal structure refinement is provided.

  14. The Crystal Structure of Cu4Bi4Se9

    DEFF Research Database (Denmark)

    Makovicky, E.; Søtofte, Inger; Karup-Møller, S.

    2002-01-01

    The crystal structure Of Cu4Bi4Se9,, synthesized at 400 degreesC, was determined from single crystal X-ray diffraction data and refined to the R, value of 0.05. The compound is orthorhombic, with a = 32.692 Angstrom, b = 4.120 Angstrom, and c = 12.202 Angstrom, space group Pnma. The structure...

  15. Undergraduates Improve upon Published Crystal Structure in Class Assignment

    Science.gov (United States)

    Horowitz, Scott; Koldewey, Philipp; Bardwell, James C.

    2014-01-01

    Recently, 57 undergraduate students at the University of Michigan were assigned the task of solving a crystal structure, given only the electron density map of a 1.3 Å crystal structure from the electron density server, and the position of the N-terminal amino acid. To test their knowledge of amino acid chemistry, the students were not given the…

  16. The Crystal Structure of Cu4Bi4Se9

    DEFF Research Database (Denmark)

    Makovicky, E.; Søtofte, Inger; Karup-Møller, S.

    2002-01-01

    The crystal structure Of Cu4Bi4Se9,, synthesized at 400 degreesC, was determined from single crystal X-ray diffraction data and refined to the R, value of 0.05. The compound is orthorhombic, with a = 32.692 Angstrom, b = 4.120 Angstrom, and c = 12.202 Angstrom, space group Pnma. The structure...

  17. CCDC 1416891: Experimental Crystal Structure Determination : Methyl-triphenyl-germanium

    KAUST Repository

    Bernatowicz, Piotr

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  18. Thermal structural properties of calcium tungstate

    Energy Technology Data Exchange (ETDEWEB)

    Senyshyn, Anatoliy; Hoelzel, Markus [Technische Univ. Darmstadt (Germany). Inst. for Materials Science; Technische Univ. Muenchen, Garching (Germany). Forschungsneutronenquelle Heinz Maier-Leibnitz FRM-II; Hansen, Thomas [Institute Laue-Langevin, Grenoble (France); Vasylechko, Leonid [Lviv Polytechnic National Univ. (Ukraine). Semiconductor Electronics Dept.; Mikhailik, Vitaliy [Diamond Light Source, Harwell Science and Innovation Campus, Didcot (United Kingdom); Oxford Univ. (United Kingdom). Dept. of Physics; Kraus, Hans [Oxford Univ. (United Kingdom). Dept. of Physics; Ehrenberg, Helmut [Technische Univ. Darmstadt (Germany). Inst. for Materials Science; IFW Dresden (Germany)

    2011-04-15

    The results of in-situ temperature-resolved powder diffraction studies of CaWO{sub 4} scheelite using both synchrotron radiation and neutron scattering are reported. The studies performed over a broad temperature range of 5-1773 K confirm the scheelite type of structure for calcium tungstate over the whole temperature range. The anisotropy of thermal expansion in calcium tungstate as well as the rigidity of WO{sub 4} complexes have been analysed in terms of bond distances, interatomic angles and anisotropic displacement parameters. The WO{sub 4}{sup 2-} complex anions showed a remarkable robustness in the whole studied temperature range, thus pointing out that the layered structure formed by two-dimensional CsCl-type arrangements of Ca cations and WO{sub 4} complexes is the primary reason for the anisotropy of thermal expansion in calcium tungstate. (orig.)

  19. Thermal Hydraulic Design of PWT Accelerating Structures

    CERN Document Server

    Yu, David; Chen Ping; Lundquist, Martin; Luo, Yan

    2005-01-01

    Microwave power losses on the surfaces of accelerating structures will transform to heat which will deform the structures if it is not removed in time. Thermal hydraulic design of the disk and cooling rods of a Plane Wave Transformer (PWT) structure is presented. Experiments to measure the hydraulic (pressure vs flow rate) and cooling (heat removed vs flow rate) properties of the PWT disk are performed, and results compared with simulations using Mathcad models and the COSMOSM code. Both experimental and simulation results showed that the heat deposited on the structure could be removed effectively using specially designed water-cooling circuits and the temperature of the structure could be controlled within the range required.

  20. Growth, spectral, optical and thermal characterization of new metallorganic crystal--bisthiourea nickel chloride.

    Science.gov (United States)

    Ramachandraraja, C; Joseph, A Antony; Sundararajan, R S; Shankar, V Siva; Murugakoothan, P

    2009-12-01

    The novel nonlinear optical single crystal of bisthiourea nickel chloride (BTNC) was grown successfully by slow evaporation technique using water as solvent. The lattice parameters of the grown crystal have been determined by X-ray diffraction studies. Vibrational spectra were recorded to determine the symmetries of molecular vibrations. Presence of various functional groups of BTNC was identified through FTIR and Raman spectroscopic analyses. Optical absorbance spectrum recorded in the wavelength range of UV-vis-NIR revealed that this crystal has good optical transparency in the range 200-2000 nm. The second harmonic generation test of BTNC revealed the nonlinear nature of the crystal. The BTNC crystal was analyzed by differential thermal and thermo gravimetric analysis (DTA-TGA) to obtain its thermal stability.

  1. Use of Pom Pons to Illustrate Cubic Crystal Structures.

    Science.gov (United States)

    Cady, Susan G.

    1997-01-01

    Describes a method that uses olefin pom pons to illustrate cubic crystal structure. Facilitates hands-on examination of different packing arrangements such as hexagonal close-packed and cubic close-packed structures. (JRH)

  2. High-speed prediction of crystal structures for organic molecules

    Science.gov (United States)

    Obata, Shigeaki; Goto, Hitoshi

    2015-02-01

    We developed a master-worker type parallel algorithm for allocating tasks of crystal structure optimizations to distributed compute nodes, in order to improve a performance of simulations for crystal structure predictions. The performance experiments were demonstrated on TUT-ADSIM supercomputer system (HITACHI HA8000-tc/HT210). The experimental results show that our parallel algorithm could achieve speed-ups of 214 and 179 times using 256 processor cores on crystal structure optimizations in predictions of crystal structures for 3-aza-bicyclo(3.3.1)nonane-2,4-dione and 2-diazo-3,5-cyclohexadiene-1-one, respectively. We expect that this parallel algorithm is always possible to reduce computational costs of any crystal structure predictions.

  3. Estimating losses in heat networks coated with modern liquid crystal thermal insulation

    Science.gov (United States)

    Ilyin, R. A.

    2015-07-01

    One of the present issues during heat network operation in Russia is the losses of thermal energy at its transfer to consumers. According to statements of experts, losses in heat networks reach 35-50%. In this work, some properties of thermo-insulating materials currently in use are described. The innovative TLM Ceramic liquid-crystal thermal insulation is presented by its positive technical and economical characteristics, as well as field-performance data, and the doubts of experts about its declared properties. Location measurement data are presented for Astrakhan Severnaya heat and power plant hot-water system section covered with the 2-mm-thick liquid-crystal thermal insulation layer. Specific heat losses from the hot-water system surface have been determined and the arguments for inexpediency of applying TLM Ceramic liquid-crystal thermal insulation in heat-and-power engineering are discussed.

  4. THERMAL LENSING MEASUREMENTS IN THE ANISOTROPIC LASER CRYSTALS UNDER DIODE PUMPING

    Directory of Open Access Journals (Sweden)

    P. A. Loiko

    2012-01-01

    Full Text Available An experimental setup was developed for thermal lensing measurements in the anisotropic diode-pumped laser crystals. The studied crystal is placed into the stable two-mirror laser cavity operating at the fundamental transversal mode. The output beam radius is measured with respect to the pump intensity for different meridional planes (all these planes contain the light propagation direction. These dependencies are fitted using the ABCD matrix method in order to obtain the sensitivity factors showing the change of the optical power of thermal lens due to variation of the pump intensity. The difference of the sensitivity factors for two mutually orthogonal principal meridional planes describes the thermal lens astigmatism degree. By means of this approach, thermal lensing was characterized in the diode-pumped monoclinic Np-cut Nd:KGd(WO42 laser crystal at the wavelength of 1.067 μm for light polarization E || Nm.

  5. Local structural ordering in surface-confined liquid crystals

    Science.gov (United States)

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

    2017-06-01

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

  6. Investigation on growth, structure and characterization of succinate salt of 8-hydroxyquinoline: an organic NLO crystal.

    Science.gov (United States)

    Thirumurugan, R; Babu, B; Anitha, K; Chandrasekaran, J

    2015-04-05

    8-Hydroxyquinolinium succinate (8-HQSU) has been synthesized and single crystals were grown from ethanol solvent by employing the technique of slow evaporation at room temperature. The structure of the grown crystal has been elucidated by single crystal X-ray diffraction analysis. It reveals that 8-HQSU crystallizes in monoclinic system with non-centro symmetric space group P2(1). FTIR, 1H and 13C NMR spectral investigations have been carried out to identify the vibrational modes of various functional groups and placement of proton and carbon in the 8-HQSU compound, respectively. UV-vis-NIR transmission spectrum shows the cutoff wavelength around 357 nm. In addition, a photoluminescence spectral analysis was carried out for 8-HQSU crystals. The thermal properties of crystals were evaluated from TGA and DTA techniques and the crystal was found to be stable up to 145°C. The dielectric studies show that the dielectric constant and dielectric loss decrease exponentially with frequency at different temperatures. Photoconductivity studies were carried out on the grown crystals it reveals the positive photo conducting nature. Powder second harmonic generation property of the crystal was confirmed by Kurtz and Perry powder SHG technique and it is found to be 1.3 times greater than that of KDP. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Synthesis, Characterization, Crystal Structure and Kinetics of Thermal Decomposition of Zn(Ⅱ) Complex%金刚乙胺水杨醛Schiff碱锌(Ⅱ)配合物的合成、表征、晶体结构和热分解动力学研究

    Institute of Scientific and Technical Information of China (English)

    赵国良; 冯云龙; 刘幸海

    2005-01-01

    A Zinc(Ⅱ) complex [ZnCl2(HL)2] with Schiff base HL derived from rimantadine and salicylaldehyde was synthesized and characterized by elemental analysis, infrared spectra, 1H NMR spectra,molar conductance, ultraviolet and visible spectra, thermal analysis. Its structure was determined by single crystal X-ray diffraction method. The complex, C38H50C12N2O2Zn, crystallizes in the orthorhombic system, space group A ba2 with a=1.381 7(3),b=2.275 0(5), c=1.145 0(2) nm, V=3.599(1) nm3, Z=4, Mr=653.79, F(000)=I 496, Dc=l.301 kg·m-3,μMo Kα)=0.866mm-1. The kinetic parameters were obtained from the analysis of TG curve by integral methods. The functions of thermal decomposition reaction mechanismtion lnA=0.019 1E-0.1427. CCDC: 253297.are: F(α)=[1-(1-α)1/3]2, and kinetic compensation effect equa-tion InA=0.019 1E-0.1427. CCDC: 253297.

  8. Evolutionary crystal structure prediction and novel high-pressure phases

    OpenAIRE

    Oganov, A. R.; Ma, Y.; Lyakhov, A. O.; Valle, M.; C. Gatti

    2010-01-01

    Prediction of stable crystal structures at given pressure-temperature conditions, based only on the knowledge of the chemical composition, is a central problem of condensed matter physics. This extremely challenging problem is often termed "crystal structure prediction problem", and recently developed evolutionary algorithm USPEX (Universal Structure Predictor: Evolutionary Xtallography) made an important progress in solving it, enabling efficient and reliable prediction of structures with up...

  9. Bismuth doping effect on crystal structure and photodegradation activity of Bi-TiO2 nanoparticles

    Science.gov (United States)

    Wu, Ming-Chung; Chang, Yin-Hsuan; Lin, Ting-Han

    2017-04-01

    The bismuth precursor is adopted as dopant to synthesize bismuth doped titanium dioxide nanoparticles (Bi-TiO2 NPs) with sol-gel method following by the thermal annealing treatment. We systematically developed a series of Bi-TiO2 NPs at several calcination temperatures and discovered the corresponding crystal structure by varying the bismuth doping concentration. At a certain 650 °C calcination temperature, the crystal structure of bismuth titanate (Bi2Ti2O7) is formed when the bismuth doping concentration is as high as 10.0 mol %. The photocatalytic activity of Bi-TiO2 NPs is increased by varying the doping concentration at the particular calcination temperature. By the definition X-ray diffraction (XRD) structural identification, a phase diagram of Bi-TiO2 NPs in doping concentration versus calcination temperature is provided. It can be useful for further study in the crystal structure engineering and the development of photocatalyst.

  10. PLANAR OPTICAL WAVEGUIDES WITH PHOTONIC CRYSTAL STRUCTURE

    DEFF Research Database (Denmark)

    2003-01-01

    Planar optical waveguide comprising a core region and a cladding region comprising a photonic crystal material, said photonic crystal material having a lattice of column elements, wherein at least a number of said column elements are elongated substantially in an axial direction for said core reg...

  11. Synthesis, spectroscopy and thermal study of some nickel(II) complexes containing tridentate Schiff bases and substituted amine ligands, X-ray crystal structure of nickel(II) complex.

    Science.gov (United States)

    Kianfar, Ali Hossein; Bahramian, Masomeh; Khavasi, Hamid Reza

    2012-08-01

    Some new tridentate ONO and ONS Schiff base complexes of [NiL(amine)] (L=Salicylidene2-aminophenol and Salicylidene2-aminothiophenol, amine=benzylamine, morpholine, pyrrolidine and piperidine) were synthesized and characterized by IR, UV-vis, (1)H NMR spectroscopy and elemental analysis. The geometry of [NiL(2)(bzlan)] determined by X-ray crystallography indicates that the complex has planar structure and has four coordinate in the solid state. The thermogravimmetry (TG) and differential thermoanalysis (DTA) of the synthesized complexes were carried out in the range of 20-700°C, leading to decomposition of ONO type in two stages and of ONS type in three stages. The ONO and ONS complexes were decomposed to NiO and NiS respectively. Thermal decomposition of the complexes is closely the depends upon nature of the Schiff base ligands and proceeds via first order kinetics.

  12. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody.

    Science.gov (United States)

    Zhu, Linxiao; Raman, Aaswath P; Fan, Shanhui

    2015-10-06

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities.

  13. Crystal structure of Clostridium difficile toxin A

    Energy Technology Data Exchange (ETDEWEB)

    Chumbler, Nicole M.; Rutherford, Stacey A.; Zhang, Zhifen; Farrow, Melissa A.; Lisher, John P.; Farquhar, Erik; Giedroc, David P.; Spiller, Benjamin W.; Melnyk, Roman A.; Lacy, D. Borden

    2016-01-11

    Clostridium difficile infection is the leading cause of hospital-acquired diarrhoea and pseudomembranous colitis. Disease is mediated by the actions of two toxins, TcdA and TcdB, which cause the diarrhoea, as well as inflammation and necrosis within the colon. The toxins are large (308 and 270 kDa, respectively), homologous (47% amino acid identity) glucosyltransferases that target small GTPases within the host. The multidomain toxins enter cells by receptor-mediated endocytosis and, upon exposure to the low pH of the endosome, insert into and deliver two enzymatic domains across the membrane. Eukaryotic inositol-hexakisphosphate (InsP6) binds an autoprocessing domain to activate a proteolysis event that releases the N-terminal glucosyltransferase domain into the cytosol. Here, we report the crystal structure of a 1,832-amino-acid fragment of TcdA (TcdA1832), which reveals a requirement for zinc in the mechanism of toxin autoprocessing and an extended delivery domain that serves as a scaffold for the hydrophobic α-helices involved in pH-dependent pore formation. A surface loop of the delivery domain whose sequence is strictly conserved among all large clostridial toxins is shown to be functionally important, and is highlighted for future efforts in the development of vaccines and novel therapeutics.

  14. Anisotropic domain structure of KTiOPO4 crystals

    Science.gov (United States)

    Urenski, P.; Lesnykh, M.; Rosenwaks, Y.; Rosenman, G.; Molotskii, M.

    2001-08-01

    Highly anisotropic ferroelectric domain structure is observed in KTiOPO4 (KTP) crystals reversed by low electric field. The applied Miller-Weinreich model for sidewise motion of domain walls indicates that this anisotropy results from the peculiarities of KTP crystal lattice. The domain nuclei of dozen nanometer size, imaged by atomic force microscopy method, demonstrate regular hexagonal forms. The orientation of domain walls of the elementary nuclei coincides with the orientation of the facets of macroscopic KTP crystals. The observed strong domain elongation along one principal crystal axis allows us to improve tailoring of ferroelectric domain engineered structures for nonlinear optical converters.

  15. Thermal transfer structures coupling electronics card(s) to coolant-cooled structure(s)

    Science.gov (United States)

    David, Milnes P; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Parida, Pritish R; Schmidt, Roger R

    2014-12-16

    Cooling apparatuses and coolant-cooled electronic systems are provided which include thermal transfer structures configured to engage with a spring force one or more electronics cards with docking of the electronics card(s) within a respective socket(s) of the electronic system. A thermal transfer structure of the cooling apparatus includes a thermal spreader having a first thermal conduction surface, and a thermally conductive spring assembly coupled to the conduction surface of the thermal spreader and positioned and configured to reside between and physically couple a first surface of an electronics card to the first surface of the thermal spreader with docking of the electronics card within a socket of the electronic system. The thermal transfer structure is, in one embodiment, metallurgically bonded to a coolant-cooled structure and facilitates transfer of heat from the electronics card to coolant flowing through the coolant-cooled structure.

  16. SiBr4--prediction and determination of crystal structures.

    Science.gov (United States)

    Wolf, Alexandra K; Glinnemann, Jürgen; Schmidt, Martin U; Tong, Jianwei; Dinnebier, Robert E; Simon, Arndt; Köhler, Jürgen

    2009-06-01

    For SiBr4 no crystal structures have been reported yet. In this work the crystal structures of SiBr4 were predicted by global lattice-energy minimizations using force-field methods. Over an energy range of 5 kJ mol(-1) above the global minimum ten possible structures were found. Two of these structures were experimentally determined from X-ray synchrotron powder diffraction data: The low-temperature beta phase crystallizes in P2(1)/c, the high-temperature alpha phase in Pa3. Temperature-dependant X-ray powder diffraction shows that the phase transition occurs at 168 K.

  17. SiBr4 - Prediction and Determination of Crystal Structures

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, A.; Glinnemann, J; Schmidt, M; Tong, J; Dinnebier, R; Simon, A; Kohler, J

    2009-01-01

    For SiBr4 no crystal structures have been reported yet. In this work the crystal structures of SiBr4 were predicted by global lattice-energy minimizations using force-field methods. Over an energy range of 5 kJ mol-1 above the global minimum ten possible structures were found. Two of these structures were experimentally determined from X-ray synchrotron powder diffraction data: The low-temperature [beta] phase crystallizes in P21/c, the high-temperature [alpha] phase in Pa overline3. Temperature-dependant X-ray powder diffraction shows that the phase transition occurs at 168 K.

  18. Crystal structure and physical properties of a dithiolene complex crystal with adamantane supramolecular rotator

    OpenAIRE

    Yan, Yin-Nan; Kubo, Kazuya; Noro, Shin-ichiro; Akutagawa, Tomoyuki; Nakamura, Takayoshi

    2014-01-01

    Supramolecular cation salt of adamantane rotator with a dithiolene complex, (fluoroadamantylammonium(+))([18]-crown-6)[Ni(dmit)(2)](-) (1) was synthesized. The fluorine atom of the adamantane unit showed a large thermal factor elongated latitudinally, suggesting molecular rotation in the solid state. Crystal 1 exhibited a large dielectric response by applying an AC field along the a axis.

  19. Crystallization and Characterization of Galdieria sulphuraria RUBISCO in Two Crystal Forms: Structural Phase Transition Observed in P21 Crystal Form

    Directory of Open Access Journals (Sweden)

    Boguslaw Stec

    2007-10-01

    Full Text Available We have isolated ribulose-1,5-bisphosphate-carboxylase/oxygenase (RUBISCOfrom the red algae Galdieria Sulphuraria. The protein crystallized in two different crystalforms, the I422 crystal form being obtained from high salt and the P21 crystal form beingobtained from lower concentration of salt and PEG. We report here the crystallization,preliminary stages of structure determination and the detection of the structural phasetransition in the P21 crystal form of G. sulphuraria RUBISCO. This red algae enzymebelongs to the hexadecameric class (L8S8 with an approximate molecular weight 0.6MDa.The phase transition in G. sulphuraria RUBISCO leads from two hexadecamers to a singlehexadecamer per asymmetric unit. The preservation of diffraction power in a phasetransition for such a large macromolecule is rare.

  20. Origin and structure of polar domains in doped molecular crystals

    Science.gov (United States)

    Meirzadeh, E.; Azuri, I.; Qi, Y.; Ehre, D.; Rappe, A. M.; Lahav, M.; Kronik, L.; Lubomirsky, I.

    2016-11-01

    Doping is a primary tool for the modification of the properties of materials. Occlusion of guest molecules in crystals generally reduces their symmetry by the creation of polar domains, which engender polarization and pyroelectricity in the doped crystals. Here we describe a molecular-level determination of the structure of such polar domains, as created by low dopant concentrations (<0.5%). The approach comprises crystal engineering and pyroelectric measurements, together with dispersion-corrected density functional theory and classical molecular dynamics calculations of the doped crystals, using neutron diffraction data of the host at different temperatures. This approach is illustrated using centrosymmetric α-glycine crystals doped with minute amounts of different L-amino acids. The experimentally determined pyroelectric coefficients are explained by the structure and polarization calculations, thus providing strong support for the local and global understanding of how different dopants influence the properties of molecular crystals.

  1. Structural Color Patterns by Electrohydrodynamic Jet Printed Photonic Crystals.

    Science.gov (United States)

    Ding, Haibo; Zhu, Cun; Tian, Lei; Liu, Cihui; Fu, Guangbin; Shang, Luoran; Gu, Zhongze

    2017-02-09

    In this work, we demonstrate the fabrication of photonic crystal patterns with controllable morphologies and structural colors utilizing electrohydrodynamic jet (E-jet) printing with colloidal crystal inks. The final shape of photonic crystal units is controlled by the applied voltage signal and wettability of the substrate. Optical properties of the structural color patterns are tuned by the self-assembly of the silica nanoparticle building blocks. Using this direct printing technique, it is feasible to print customized functional patterns composed of photonic crystal dots or photonic crystal lines according to relevant printing mode and predesigned tracks. This is the first report for E-jet printing with colloidal crystal inks. Our results exhibit promising applications in displays, biosensors, and other functional devices.

  2. Structural, Thermal, Linear and Nonlinear Optical Studies on New NLO Crystal∶DL-Threonium Trichloroacetate

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Crystals of DL-threonium trichloroacetate (DLTTCA) was synthesized from an aqueous solution by slow evaporation technique. The grown crystals were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, UV-Vis-NIR and SHG measurements. Vibrational structure of the crystal was elucidated from FTIR analysis and the hydrogen bond interactions were discussed in detail. The ultraviolet transparent cutoff falls at 212 nm. Thermal stability of the compound was also studied. The powder SHG efficiency of the compound was measured as 0.62 times to that of KDP.

  3. Could thermal fluctuations seed cosmic structure?

    CERN Document Server

    Magueijo, J; Magueijo, Joao; Pogosian, Levon

    2003-01-01

    We examine the possibility that thermal, rather than quantum, fluctuations are responsible for seeding the structure of our universe. We find that while the thermalization condition leads to nearly Gaussian statistics, a Harrisson-Zeldovich spectrum for the primordial fluctuations can only be achieved in very special circumstances. These depend on whether the universe gets hotter or colder in time, while the modes are leaving the horizon. In the latter case we find a no-go theorem which can only be avoided if the fundamental degrees of freedom are not particle-like, such as in string gases near the Hagedorn phase transition. The former case is less forbidding, and we suggest two potentially successful ``warming universe'' scenarios. One makes use of the Phoenix universe, the other of ``phantom'' matter.

  4. Crystal fingerprint space--a novel paradigm for studying crystal-structure sets.

    Science.gov (United States)

    Valle, Mario; Oganov, Artem R

    2010-09-01

    The initial aim of the crystal fingerprint project was to solve a very specific problem: to classify and remove duplicate crystal structures from the results generated by the evolutionary crystal-structure predictor USPEX. These duplications decrease the genetic diversity of the population used by the evolutionary algorithm, potentially leading to stagnation and, after a certain time, reducing the likelihood of predicting essentially new structures. After solving the initial problem, the approach led to unexpected discoveries: unforeseen correlations, useful derived quantities and insight into the structure of the overall set of results. All of these were facilitated by the project's underlying idea: to transform the structure sets from the physical configuration space to an abstract, high-dimensional space called the fingerprint space. Here every structure is represented as a point whose coordinates (fingerprint) are computed from the crystal structure. Then the space's distance measure, interpreted as structure 'closeness', enables grouping of structures into similarity classes. This model provides much flexibility and facilitates access to knowledge and algorithms from fields outside crystallography, e.g. pattern recognition and data mining. The current usage of the fingerprint-space model is revealing interesting properties that relate to chemical and crystallographic attributes of a structure set. For this reason, the mapping of structure sets to fingerprint space could become a new paradigm for studying crystal-structure ensembles and global chemical features of the energy landscape.

  5. Nanoconfinement-Induced Structures in Chiral Liquid Crystals

    OpenAIRE

    2013-01-01

    We employ Monte Carlo simulations in a specialized isothermal-isobaric and in the grand canonical ensemble to study structure formation in chiral liquid crystals as a function of molecular chirality. Our model potential consists of a simple Lennard-Jones potential, where the attractive contribution has been modified to represent the orientation dependence of the interaction between a pair of chiral liquid-crystal molecules. The liquid crystal is confined between a pair of planar and atomicall...

  6. Crystal structure and characterization of pyrroloquinoline quinone disodium trihydrate

    Directory of Open Access Journals (Sweden)

    Ikemoto Kazuto

    2012-06-01

    Full Text Available Abstract Background Pyrroloquinoline quinone (PQQ, a tricarboxylic acid, has attracted attention as a growth factor, and its application to supplements and cosmetics is underway. The product used for these purposes is a water-soluble salt of PQQ disodium. Although in the past, PQQ disodiumpentahydrates with a high water concentration were used, currently, low hydration crystals of PQQ disodiumpentahydrates are preferred. Results We prepared a crystal of PQQ disodium trihydrate in a solution of ethanol and water, studied its structure, and analyzed its properties. In the prepared crystal, the sodium atom interacted with the oxygen atom of two carboxylic acids as well as two quinones of the PQQ disodium trihydrate. In addition, the hydration water of the prepared crystal was less than that of the conventional PQQ disodium crystal. From the results of this study, it was found that the color and the near-infrared (NIR spectrum of the prepared crystal changed depending on the water content in the dried samples. Conclusions The water content in the dried samples was restored to that in the trihydrate crystal by placing the samples in a humid environment. In addition, the results of X-ray diffraction (XRD and X-ray diffraction-differential calorimetry (XRD-DSC analyses show that the phase of the trihydrate crystal changed when the crystallization water was eliminated. The dried crystal has two crystalline forms that are restored to the original trihydrate crystals in 20% relative humidity (RH. This crystalline (PQQ disodium trihydrate is stable under normal environment.

  7. Structure and Properties of Liquid Crystals

    CERN Document Server

    Blinov, Lev M

    2011-01-01

    This book by Lev M. Blinov is ideal to guide researchers from their very first encounter with liquid crystals to the level where they can perform independent experiments on liquid crystals with a thorough understanding of their behaviour also in relation to the theoretical framework. Liquid crystals can be found everywhere around us. They are used in virtually every display device, whether it is for domestic appliances of for specialized technological instruments. Their finely tunable optical properties make them suitable also for thermo-sensing and laser technologies. There are many monographs written by prominent scholars on the subject of liquid crystals. The majority of them presents the subject in great depth, sometimes focusing on a particular research aspect, and in general they require a significant level of prior knowledge. In contrast, this books aims at an audience of advanced undergraduate and graduate students in physics, chemistry and materials science. The book consists of three parts: the firs...

  8. Thermal Mechanical Stability of Single-Crystal-Oxide Refractive Concentrators Evaluated for High-Temperature Solar-Thermal Propulsion

    Science.gov (United States)

    Jacobson, Nathan S.; Jacobson, Nathan S.; Miller, Robert A.

    1999-01-01

    Recently, refractive secondary solar concentrator systems were developed for solar thermal power and propulsion (ref. 1). Single-crystal oxides-such as yttria-stabilized zirconia (Y2O3-ZrO2), yttrium aluminum garnet (Y3Al5O12, or YAG), magnesium oxide (MgO), and sapphire (Al2O3)-are candidate refractive secondary concentrator materials. However, the refractive concentrator system will experience high-temperature thermal cycling in the solar thermal engine during the sun/shade transition of a space mission. The thermal mechanical reliability of these components in severe thermal environments is of great concern. Simulated mission tests are important for evaluating these candidate oxide materials under a variety of transient and steady-state heat flux conditions. In this research at the NASA Lewis Research Center, a controlled heat flux test approach was developed for investigating the thermal mechanical stability of the candidate oxide. This approach used a 3.0-kW continuous-wave (wavelength, 10.6 mm) carbon dioxide (CO2) laser (ref. 2). The CO2 laser is especially well-suited for single-crystal thermal shock tests because it can directly deliver well-characterized heat energy to the oxide surfaces. Since the oxides are opaque at the 10.6-mm wavelength of the laser beam, the light energy is absorbed at the surfaces rather than transmitting into the crystals, and thus generates the required temperature gradients within the specimens. The following figure is a schematic diagram of the test rig.

  9. The crystal structure of some rhenium and technetium dichalcogenides

    NARCIS (Netherlands)

    Lamfers, H.J; Meetsma, A.; Wiegers, G.A; deBoer, J.L.

    1996-01-01

    The crystal structures of ReSe2,ReS2, ReSSe and TcS2 are determined using single crystal X-ray diffraction. The compounds are triclinic with space group P (1) over bar. ReSe2, Res(2) and ReSSe have a distorted CdCl2-type structure; TcS2 has a distorted Cd(OH)(2)-type structure. In the case of Res,

  10. Growth, spectral, optical, thermal, and mechanical behaviour of an organic single crystal: Quinolinium 2-carboxy 6-nitrophthalate monohydrate

    Science.gov (United States)

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

    2016-09-01

    Organic single crystals of quinolinium 2-carboxy 6-nitrophthalate monohydrate (QN) were grown by slow evaporation solution growth technique using ethanol and water as a mixed solvent. X-ray powder diffraction analysis revealed that the crystal belongs to the monoclinic crystal system with space group of P21/c. The functional groups present in the crystallized material confirmed its molecular structure. The optical transparency range and the lower cutoff wavelength were identified from the UV-vis spectrum. The optical constants were determined by UV-visible transmission spectrum at normal incidence, measured over the 200-700 nm spectral range. The dispersion of the refractive index was discussed in terms of the single-oscillator Wemple and DiDomenico model. The calculated HOMO and LUMO energies show that the charge transfer occur within the molecule. Electronic excitation properties were discussed within the framework of two level model on the basis of an orbital analysis. The nonlinear optical absorption coefficient (β) and nonlinear refraction (n2) of QN was measured by Z-scan technique and reported here. Thermal stability of QN was determined using TGA/DSC curves. Vicker's microhardness studies were carried out on the (1 1 ̅0) plane to understand the mechanical properties of the grown crystal. The microhardness measurements showed a Vickers hardness value as 18.4 kg/mm2 which is comparable to well-known organic crystal, urea.

  11. Exchange-Hole Dipole Dispersion Model for Accurate Energy Ranking in Molecular Crystal Structure Prediction.

    Science.gov (United States)

    Whittleton, Sarah R; Otero-de-la-Roza, A; Johnson, Erin R

    2017-02-14

    Accurate energy ranking is a key facet to the problem of first-principles crystal-structure prediction (CSP) of molecular crystals. This work presents a systematic assessment of B86bPBE-XDM, a semilocal density functional combined with the exchange-hole dipole moment (XDM) dispersion model, for energy ranking using 14 compounds from the first five CSP blind tests. Specifically, the set of crystals studied comprises 11 rigid, planar compounds and 3 co-crystals. The experimental structure was correctly identified as the lowest in lattice energy for 12 of the 14 total crystals. One of the exceptions is 4-hydroxythiophene-2-carbonitrile, for which the experimental structure was correctly identified once a quasi-harmonic estimate of the vibrational free-energy contribution was included, evidencing the occasional importance of thermal corrections for accurate energy ranking. The other exception is an organic salt, where charge-transfer error (also called delocalization error) is expected to cause the base density functional to be unreliable. Provided the choice of base density functional is appropriate and an estimate of temperature effects is used, XDM-corrected density-functional theory is highly reliable for the energetic ranking of competing crystal structures.

  12. Photonic Crystal Structures with Tunable Structure Color as Colorimetric Sensors

    Directory of Open Access Journals (Sweden)

    Ke-Qin Zhang

    2013-03-01

    Full Text Available Colorimetric sensing, which transduces environmental changes into visible color changes, provides a simple yet powerful detection mechanism that is well-suited to the development of low-cost and low-power sensors. A new approach in colorimetric sensing exploits the structural color of photonic crystals (PCs to create environmentally-influenced color-changeable materials. PCs are composed of periodic dielectrics or metallo-dielectric nanostructures that affect the propagation of electromagnetic waves (EM by defining the allowed and forbidden photonic bands. Simultaneously, an amazing variety of naturally occurring biological systems exhibit iridescent color due to the presence of PC structures throughout multi-dimensional space. In particular, some kinds of the structural colors in living organisms can be reversibly changed in reaction to external stimuli. Based on the lessons learned from natural photonic structures, some specific examples of PCs-based colorimetric sensors are presented in detail to demonstrate their unprecedented potential in practical applications, such as the detections of temperature, pH, ionic species, solvents, vapor, humidity, pressure and biomolecules. The combination of the nanofabrication technique, useful design methodologies inspired by biological systems and colorimetric sensing will lead to substantial developments in low-cost, miniaturized and widely deployable optical sensors.

  13. Thermal-Mechanical Stability of Single Crystal Oxide Refractive Concentrators for High-Temperature Solar Thermal Propulsion

    Science.gov (United States)

    Zhu, Dongming; Jacobson, Nathan S.; Miller, Robert A.

    1999-01-01

    Single crystal oxides such as yttria-stabilized zirconia (Y2O3-ZrO2), yttrium aluminum garnet (Y3Al5O12, or YAG), magnesium oxide (MgO) and sapphire (Al2O3) are candidate refractive secondary concentrator materials for high temperature solar propulsion applications. However, thermo-mechanical reliability of these components in severe thermal environments during the space mission sun/shade transition is of great concern. Simulated mission tests are important for evaluating these candidate oxide materials under a variety of transient and steady-state heat flux conditions, and thus provide vital information for the component design. In this paper, a controlled heat flux thermal shock test approach is established for the single crystal oxide materials using a 3.0 kW continuous wave CO2 laser, with a wavelength 10.6 micron. Thermal fracture behavior and failure mechanisms of these oxide materials are investigated and critical temperature gradients are determined under various temperature and heating conditions. The test results show that single crystal sapphire is able to sustain the highest temperature gradient and heating-cooling rate, and thus exhibit the best thermal shock resistance, as compared to the yttria-stabilized zirconia, yttrium aluminum garnet and magnesium oxide.

  14. Effect of the thermal history of glass melts on crystallization in lithium and sodium disilicate glasses doped with platinum as a nucleating agent

    Energy Technology Data Exchange (ETDEWEB)

    Mishima, Naofumi, E-mail: mishima@ms.kochi-ct.ac.jp; Kawasaki, Yuji

    2016-02-15

    The crystallization behavior of Li{sub 2}O–Na{sub 2}O–2SiO{sub 2} glasses with different thermal histories was examined. The glass melts were doped with 0.005 wt% platinum, held at various temperatures (>T{sub L}) and then water-quenched, and glasses were obtained. Measurements revealed distinctly different crystallization tendencies between glasses whose melt was held at just above the liquidus temperature and glasses whose melt was held at a higher temperature. After double-stage heat treatments, the glasses were crystallized, and needle-like crystals (Li{sub 2}O·SiO{sub 2}) and spherical crystals (Li{sub 2}O·SiO{sub 2}) formed. In particular, platinum-derived nuclei promoted the generation of Li{sub 2}O·SiO{sub 2} crystal. Microscopic observations showed that both crystal particles precipitating in the interior of the crystallized glasses increased in number as the holding temperature decreased. The exothermic crystallization peak of the glass held at a lower temperature appeared earlier than that of the glass with a higher holding temperature in the profile of differential thermal analysis. Additionally, the precipitated amount of Li{sub 2}O·SiO{sub 2} obtained from X-ray diffraction measurement increased with decreasing holding temperature. These results suggest that the distribution of platinum colloids in glass melts varies depending on the holding temperature. - Highlights: • Pt-doped Li{sub 2}O–Na{sub 2}O–2SiO{sub 2} glasses were produced. • Glasses were synthesized by holding melts at various temperatures. • Crystallization behaviors of glasses with different thermal histories were examined. • Crystal particles increased in number as the holding temperature decreased. • Melt structure was estimated from crystallization depending on holding temperature.

  15. Structure and thermal stability of nanocrystalline materials

    Indian Academy of Sciences (India)

    B S Murty; M K Datta; S K Pabi

    2003-02-01

    Nanocrystalline materials, which are expected to play a key role in the next generation of human civilization, are assembled with nanometre-sized “building blocks” consisting of the crystalline and large volume fractions of intercrystalline components. In order to predict the unique properties of nanocrystalline materials, which are a combination of the properties of the crystalline and intercrystalline regions, it is essential to understand precisely how the structures of crystalline and intercrystalline regions vary with decrease in crystallite size. In addition, study of the thermal stability of nanocrystalline materials against significant grain growth is both scientific and technological interest. A sharp increase in grain size (to micron levels) during consolidation of nanocrystalline powders to obtain fully dense materials may consequently result in the loss of some unique properties of nanocrystalline materials. Therefore, extensive interest has been generated in exploring the size effects on the structure of crystalline and intercrystalline region of nanocrystalline materials, and the thermal stability of nanocrystalline materials against significant grain growth. The present article is aimed at understanding the structure and stability of nanocrystalline materials.

  16. Functional substitution of coordination polyhedron in crystal structure of silicates

    Institute of Scientific and Technical Information of China (English)

    叶大年; 马哲生; 赫伟; 李哲; 施倪承; D.Pushcharovsky

    2002-01-01

    On the bases of the study of comparative crystal chemistry of silicates it has been concluded that the octahedra and square pyramids of Ti-0 and Zr-O play functional role of tetrahedra of Si-O in the construction of crystal structures. Therefore, those silicates may be named titano-and zircono-silicates. Because of the functional similarity of coordination polyhedra, the structures of cristobalite and feldspar have been compared with those of perovskite and garnet, respectively. As a new concept, the functional replacement of tetrahedra by octahedra and/or pyramids is defined by the authors of this paper for favorable comparison of relative crystal structures.

  17. Hot Views on Cold Crystals: The Application of Thermal Imaging in Cryocrystallography

    Science.gov (United States)

    Snell, Eddie H.

    2003-01-01

    In the past we have used thermal imaging techniques to visualize the cryocooling processes of macromolecular crystals. From these images it was clear that a cold wave progresses through a crystal starting at the face closest to the origin of the cold stream and ending at the point furthest away. During these studies we used large volume crystals, which were clearly distinguished from the loop holding them. These large crystals, originally grown for neutron diffraction studies, were chosen deliberately to enhance the imaging. As an extension to this work, we used thermal imaging to study small crystals, held in a cryo- loop, in the presence of vitrified mother liquor. The different infrared transmission and reflectance properties of the crystal in comparison to the mother liquor surrounding it are thought to be the parameter that produces the contrast that makes the crystal visible. An application of this technology may be the determination of the exact location of small crystals in a cryo-loop. Data from initial tests in support of application development was recorded for lysozyme crystals and for bFGF/dna complex crystals, which were cryo-cooled and imaged in large loops, both with visible light and with infrared radiation. The crystals were clearly distinguished from the vitrified solution in the infrared spectrum, while in the case of the bFGF/dna complex the illumination had to be carefully manipulated to make the crystal visible in the visible spectrum. These results suggest that the thermal imaging may be more sensitive than visual imaging for automated location of small crystals. However, further work on small crystals robotically mounted at SSRL did not clearly visualize those crystals. The depth of field of the camera proved to be limiting and a different cooling geometry was used, compared to the previous, successful experiments. Analysis to exploit multiple images to improve depth of field and experimental work to understand cooling geometry effects is

  18. Hot Views on Cold Crystals: The Application of Thermal Imaging in Cryo-crystallography

    Science.gov (United States)

    Snell, E. H.; vanderWoerd, M. J.; Deacon, A.

    2003-01-01

    In the past we have used thermal imaging techniques to visualize the cryocooling processes of macromolecular crystals. From these images it was clear that a cold wave progresses through a crystal starting at the face closest to the origin of the cold stream and ending at the point furthest away. During these studies we used large volume crystals, which were clearly distinguished from the loop holding them. These large crystals, originally grown for neutron diffraction studies, were chosen deliberately to enhance the imaging. As an extension to this work, we present used thermal imaging to study small crystals, held in a cryo-loop, in the presence of vitrified mother liquor. The different infrared transmission and reflectance properties of the crystal in comparison to the mother liquor surrounding it are thought to be the parameter that produces the contrast that makes the crystal visible. An application of this technology may be the determination of the exact location of small crystals in a cryo-loop. Data from initial tests in support of application development was recorded for lysozyme crystals and for bFGF/dna complex crystals, which were cryo-cooled and imaged in large loops, both with visible light and with infrared radiation. The crystals were clearly distinguished from the vitrified solution in the infrared spectrum, while in the case of the bFGF/dna complex the illumination had to be carefully manipulated to make the crystal visible in the visible spectrum. These results suggest that the thermal imaging may be more sensitive than visual imaging for automated location of small crystals. However, further work on small crystals robotically mounted at SSRL did not clearly visualize those crystals. The depth of field of the camera proved to be limiting and a different cooling geometry was used, compared to the previous, successful experiments. Analysis to exploit multiple images to improve depth of field and experimental work to understand cooling geometry

  19. Thermal stimulated current response in cupric oxide single crystal thin films over a wide temperature range

    Science.gov (United States)

    Yang, Kungan; Wu, Shuxiang; Yu, Fengmei; Zhou, Wenqi; Wang, Yunjia; Meng, Meng; Wang, Gaili; Zhang, Yueli; Li, Shuwei

    2017-01-01

    Cupric oxide single crystal thin films (~26 nm) were grown by plasma-assisted molecular beam epitaxy. X-ray diffraction, Raman spectra and in situ reflection high-energy electron diffraction show that the thin films are 2  ×  2 reconstructed with an in-plane compression and out-of-plane stretching. A thermal stimulated current measurement indicates that the electric polarization response is shown in the special 2D cupric oxide single crystal thin film over a wide temperature range from 130 K to near-room temperature. We infer that the abnormal electric response involves the changing of phase transition temperature induced by structure distortion, the spin frustration and the magnetic fluctuation effect of a short-range magnetic order, or the combined action of both of the two factors mentioned above. This work suggests a promising clue for finding new room temperature single phase multiferroics or tuning phase transition temperatures.

  20. Thermal kinetic and dielectric parameters of acenaphthene crystal grown by vertical Bridgman technique

    Science.gov (United States)

    Karuppusamy, S.; Dinesh Babu, K.; Nirmal Kumar, V.; Gopalakrishnan, R.

    2016-05-01

    The bulk acenaphthene crystal was grown in a single-wall ampoule by vertical Bridgman technique. X-ray diffraction analysis confirmed the orthorhombic crystal system of title compound with space group Pcm21. Thermal behavior of compound was studied using thermogravimetry—differential scanning calorimetry analysis. Thermal kinetic parameters like activation energy, frequency factor, Avrami exponent, reaction rate and degree of conversion were calculated using Kissingers and Ozawa methods under non-isothermal condition for acenaphthene crystal and reported for the first time. The calculated thermal kinetic parameters are presented. Dielectric studies were performed to calculate the dielectric parameters such as dielectric constant, dielectric loss, AC conductivity, and activation energy from Arrhenius plot.

  1. The growth, spectral and thermal properties of the coordination compound crystal-strontium malate

    Energy Technology Data Exchange (ETDEWEB)

    Jini, T.; Saban, K.V.; Varghese, G. [Department of Physics, St. Berchmans College, Changanassery, Kerala 686 101 (India)

    2006-03-15

    Growth of single crystals of the title compound Sr(C{sub 4}H{sub 4}O{sub 5}).3H{sub 2}O is achieved using the gel diffusion technique. Multifaceted single crystals of size up to 4x3x3 mm{sup 3}are obtained. X-Ray Diffraction (XRD) pattern of the grown crystal and the Fourier Transform Infra-Red (FTIR) spectrum in the range 400-4000 cm {sup -1}are recorded. The vibrational bands corresponding to different functional groups are assigned. Thermal behavior of the material is investigated using Thermo Gravimetry (TG) and Differential Thermal Analysis (DTA). Thermal studies are indicative of a five-stage decomposition scheme. copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim. (orig.)

  2. Normal processes of phonon-phonon scattering and thermal conductivity of germanium crystals with isotopic disorder

    CERN Document Server

    Kuleev, I G

    2001-01-01

    The effect of normal processes of the phonon-phonon scattering on the thermal conductivity of the germanium crystals with various isotopic disorder degrees is considered. The phonon pulse redistribution in the normal scattering processes both inside each oscillatory branch (the Simons mechanism) and between various phonon oscillatory branches (the Herring mechanism) is accounted for. The contributions of the longitudinal and cross-sectional phonons drift motion into the thermal conductivity are analyzed. It is shown that the pulse redistribution in the Herring relaxation mechanism leads to essential suppression of the longitudinal phonons drift motion in the isotopically pure germanium crystals. The calculations results of thermal conductivity for the Herring relaxation mechanism agree well with experimental data on the germanium crystals with various isotopic disorder degrees

  3. Thermal characteristics of pure and substituted gel grown Gd-molybdate crystals

    Indian Academy of Sciences (India)

    Vinay Hangloo; K K Bamzai; P N Kotru; M L Koul

    2004-10-01

    Polycrystalline spherulitic crystals of pure Gd-heptamolybdate and single and twinned crystals of substituted Gd–Ba-molybdate were grown by using gel encapsulation technique. The thermal behaviour of these crystals was studied using the thermoanalytical techniques, which included TG, DTA and DSC. Thermal analysis suggests decomposition of the materials in one or more than one stages. Results obtained on application of TG based models viz. Horowitz–Metzger, Coats–Redfern and Piloyan–Novikova, are reported. According to the results of the kinetics of thermal decomposition, the random nucleation model is shown to be the one that is relevant to the decomposition of single rare earth (Gd) containing material and contracting sphere to the decomposition of the substituted (Gd–Ba) one. The kinetic parameters viz. the order of reaction, frequency factor and energy of activation using above-mentioned models, are computed and shown to bear reasonably good agreement.

  4. Numerical Modeling on Thermal Loading of Diamond Crystal in X-ray FEL Oscillator

    CERN Document Server

    Song, Meiqi; Guo, Yuhang; Li, Kai; Deng, Haixiao

    2015-01-01

    Due to high reflectivity and high resolution to X-ray pulse, diamond is one of the most popular Bragg crystals serving as the reflecting mirror and mono-chromator in the next generation free electrons lasers (FELs). The energy deposition of X-rays will result in thermal heating, and thus lattice expanding of diamond crystal, which may degrade the performance of X-ray FELs. In this paper, the thermal loading effect of diamond crystal for X-ray FEL oscillator has been systematically studied by the combined simulation of Geant4 and ANSYS, and its dependence on the environment temperature, crystal size, X-ray pulse repetition rate and pulse energy are presented.

  5. X-Ray structural investigation of VAS-393 crystals

    CERN Document Server

    Martirosian, A H; Harurtjunian, V S

    2001-01-01

    X-ray structural study of VAS-393 crystals was performed. Investigations were carried out with the use of the Weissenberg rotating and powder (employing the Bjornstrem diagrams) methods. The lattice constants ''c'' and ''a''are calculated. The crystal is shown to belong to the trigonal syngony (medium category)

  6. Missing strings of residues in protein crystal structures.

    Science.gov (United States)

    Djinovic-Carugo, Kristina; Carugo, Oliviero

    2015-01-01

    A large fraction of the protein crystal structures deposited in the Protein Data Bank are incomplete, since the position of one or more residues is not reported, despite these residues are part of the material that was analyzed. This may bias the use of the protein crystal structures by molecular biologists. Here we observe that in the large majority of the protein crystal structures strings of residues are missing. Polar residues incline to occur in missing strings together with glycine, while apolar and aromatic residues tend to avoid them. Particularly flexible residues, as shown by their extremely high B-factors, by their exposure to the solvent and by their secondary structures, flank the missing strings. These data should be a helpful guideline for crystallographers that encounter regions of flat and uninterpretable electron density as well as end-users of crystal structures.

  7. Crystal structure of homoisocitrate dehydrogenase from Schizosaccharomyces pombe

    Energy Technology Data Exchange (ETDEWEB)

    Bulfer, Stacie L.; Hendershot, Jenna M.; Trievel, Raymond C. (Michigan); (UCSF)

    2013-09-18

    Lysine biosynthesis in fungi, euglena, and certain archaebacteria occurs through the {alpha}-aminoadipate pathway. Enzymes in the first steps of this pathway have been proposed as potential targets for the development of antifungal therapies, as they are absent in animals but are conserved in several pathogenic fungi species, including Candida, Cryptococcus, and Aspergillus. One potential antifungal target in the {alpha}-aminoadipate pathway is the third enzyme in the pathway, homoisocitrate dehydrogenase (HICDH), which catalyzes the divalent metal-dependent conversion of homoisocitrate to 2-oxoadipate (2-OA) using nicotinamide adenine dinucleotide (NAD{sup +}) as a cofactor. HICDH belogns to a family of {beta}-hydroxyacid oxidative decarboxylases that includes malate dehydrogenase, tartrate dehydrogenase, 6-phosphogluconate dehydrogenase, isocitrate dehydrogenase (ICDH), and 3-isopropylmalte dehydrogenase (IPMDH). ICDH and IPMDH are well-characterized enzymes that catalyze the decarboxylation of isocitrate to yield 2-oxoglutarate (2-OG) in the citric acid cycle and the conversion of 3-isopropylmalate to 2-oxoisovalerate in the leucine biosynthetic pathway, respectively. Recent structural and biochemical studies of HICDH reveal that this enzyme shares sequence, structural, and mechanistic homology with ICDH and IPMDH. To date, the only published structures of HICDH are from the archaebacteria Thermus thermophilus (TtHICDH). Fungal HICDHs diverge from TtHICDH in several aspects, including their thermal stability, oligomerization state, and substrate specificity, thus warranting further characterization. To gain insights into these differences, they determined crystal structures of a fungal Schizosaccharomyces pombe HICDH (SpHICDH) as an apoenzyme and as a binary complex with additive tripeptide glycyl-glycyl-glycine (GGG) to 1.55 {angstrom} and 1.85 {angstrom} resolution, respectively. Finally, a comparison of the SpHICDH and TtHICDH structures reveal differences in

  8. Electrical and thermal conductivities of rapidly crystallized Cu-Zr alloys: The effect of anharmonicity

    Science.gov (United States)

    Uporov, S.; Bykov, V.; Estemirova, S.

    2016-10-01

    We present a comprehensive study of electrical and thermal conductivities, specific heat and magnetic susceptibility of rapidly crystallized Cu100-xZrx (x = 20-90) alloys. X-ray diffraction analysis has revealed that all the prepared compositions had strongly textured and distorted crystal structures. Different monoclinic and other non-equilibrium phases were detected in the case of glass-forming samples, whereas the alloys without a tendency to form glassy state show almost equilibrium phase content. Metallic type of electrical conductivity and the Kondo anomaly were observed for all the examined samples. It was found that the electrical resistance data cannot be adequately described within the standard Bloch-Grüneisen theory. We use the Debye characteristic temperature as a linear function to fit the electrical conductivity accurately. The composition dependence of the electron density of states at the Fermi level (DOS) has been extracted from room temperature magnetic susceptibility. We found that the glass-forming alloys are characterized by abnormally large values of DOS, which are comparable to those of glassy analogues. Noticeable anharmonic contribution in total specific heat has been revealed for all the studied compositions. In order to estimate the effect of anharmonicity in the system under consideration, we analyzed composition and temperature dependencies of the studied thermal characteristics related to the Grüneisen coefficient. Basing on the results obtained in this study we propose a phenomenological concept to explain abnormal behavior of physical properties of glass-forming Cu-Zr alloys within the standard solid state theory taking into account anharmonic effects.

  9. Growth morphology and structural characteristic of C70single crystals

    Institute of Scientific and Technical Information of China (English)

    周维亚; 解思深; 吴源; 常保和; 王刚; 钱露茜

    1999-01-01

    Large size C70 single crystals with the dimension of more than 5 mm are grown from the vapor phase by controlling nucleation. X-ray diffraction and electron diffraction confirm that in the C70 single crystal a phase of the hexagonal close-packed (hcp) structure coexists with a minor face-center-cubic (fcc) phase at room temperature. The morphologies and their formation mechanism of the C70 single crystals are investigated by means of scanning electron microscopy and optical microscopy. The influence of growth conditions on the morphologies of C70 single crystals is discussed.

  10. Structural and mechanical studies of cadmium manganese thiocyanate crystal

    Science.gov (United States)

    Manikandan, M. R.; Vijayaprasath, G.; babu, G. Anandha; Bhagavannarayan, G.; Vijayan, N.; Ravi, G.

    2012-06-01

    Single crystals of cadmium manganese thiocyanate (CMTC) have been synthesized successfully and grown by slow evaporation method. The structural perfection of the grown crystals has been analyzed by High resolution X-ray diffraction (HRXRD), which shows the crystalline perfection of the grown crystal is quite good. Optical behavior was assessed by UV-Vis analysis and found that no absorption in the UV visible region and it may be useful for second harmonic applications. The mechanical hardness of the grown crystals was studied and Vicker's microhardness, Stiffness constant was calculated.

  11. [Sr(CHZ)(TNR)(H2O)(OH)]2·2H2O的晶体结构和热分解机理%Crystal Structure and Thermal Decomposition Mechanism of [Sr(CHZ)(TNR)(H2O)(OH)]2· 2H2O

    Institute of Scientific and Technical Information of China (English)

    郑红; 张同来; 张建国; 乔小晶; 杨利; 孙远华

    2006-01-01

    The coordination compound of [Sr(CHZ) (TNR)(H2O) (OH)]2· 2H2O (TNR: 2,4,6-trinitroesorcinol, CHZ:carbohydrazide) was prepared by reacting CHZ solution and strontium styphnate solution (obtained through the reaction of strontium carbonate and styphnic acid). The molecular structure was characterized by using X-ray diffraction analysis, element analysis and FTIR analysis. The crystal belongs to triclinic with space group P(-1). The unit cell parameters were as follows: a=0.725 2(2) nm, b=1.021 2(2) nm, c=1.144 0(2) nm, α=69.50(3)°, β=78.82(3)°, γ=84.64(3)° and Z=2. The thermal decomposition of the compound is studied using differential scanning calorimetry (DSC) and thermogravimetry thermogravimetry-derivative (TG-DTG) techniques. CCDC: 269310.

  12. Preparation and thermal decomposition mechanism of Mg,Al-hydrotalcite nano-crystals with titania doping

    Institute of Scientific and Technical Information of China (English)

    REN Qing-li; LUO Qiang

    2006-01-01

    The highly pure nano-crystal Mg,Al-hydrotalcite with titania doping was synthesized by one-step liquid reaction method at atmospheric pressure. The preparation of the Mg,Al-hydrotalcite nano-crystal after doping titania was investigated according to the results of XRD,TEM,IR and DSC. Moreover,based on the DSC test results,the thermal mechanism functions of the Mg,Al-hydrotalcite with titania doping were studied after calculation and comparison.

  13. Comparative Analysis of Thermal Behavior, Isothermal Crystallization Kinetics and Polymorphism of Palm Oil Fractions

    OpenAIRE

    Zhang, Xia; Lin LI; Xie, He; Liang, Zhili; Su, Jianyu; Liu, Guoqin; LI, Bing

    2013-01-01

    Thermal behavior of palm stearin (PS) and palm olein (PO) was explored by monitoring peak temperature transitions by differential scanning calorimetry (DSC). The fatty acid composition (FAC), isothermal crystallization kinetics studied by pulsed Nuclear Magnetic Resonance (pNMR) and isothermal microstructure were also compared. The results indicated that the fatty acid composition had an important influence on the crystallization process. PS and PO both exhibited more multiple endotherms than...

  14. Effective group index of refraction in non-thermal plasma photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Mousavi, A.; Sadegzadeh, S., E-mail: sadegzadeh@azaruniv.edu [Physics Department, Azarbaijan Shahid Madani University, Tabriz (Iran, Islamic Republic of)

    2015-11-15

    Plasma photonic crystals (PPCs) are periodic arrays that consist of alternate layers of micro-plasma and dielectric. These structures are used to control the propagation of electromagnetic waves. This paper presents a survey of research on the effect of non-thermal plasma with bi-Maxwellian distribution function on one dimensional PPC. A plasma with temperature anisotropy is not in thermodynamic equilibrium and can be described by the bi-Maxwellian distribution function. By using Kronig-Penny's model, the dispersion relation of electromagnetic modes in one dimensional non-thermal PPC (NPPC) is derived. The band structure, group velocity v{sub g}, and effective group index of refraction n{sub eff}(g) of such NPPC structure with TeO{sub 2} as the material of dielectric layers have been studied. The concept of negative group velocity and negative n{sub eff}(g), which indicates an anomalous behaviour of the PPCs, are also observed in the NPPC structures. Our numerical results provide confirmatory evidence that unlike PPCs there are finite group velocity and non-zero effective group indexes of refraction in photonic band gaps (PBGs) that lie in certain ranges of normalized frequency. In other words, inside the PBGs of NPPCs, n{sub eff}(g) becomes non-zero and photons travel with a finite group velocity. In this special case, this velocity varies alternately between 20c and negative values of the order 10{sup 3}c (c is the speed of light in vacuum)

  15. Faraday isolator based on a TSAG single crystal with compensation of thermally induced depolarization inside magnetic field

    Science.gov (United States)

    Snetkov, Ilya; Palashov, Oleg

    2015-04-01

    A Faraday isolator based on a terbium scandium aluminum garnet (TSAG) single crystal with compensation of thermally induced depolarization inside magnetic field was demonstrated. An isolation ratio of 32 dB at 350 W cw laser radiation power was achieved. Thermally induced depolarization and thermal lens were studied and compared with similar thermal effects arising in the widely used terbium gallium garnet crystal (TGG) for the first time.

  16. Composition, structure and properties of sediment thermal springs of Kamchatka

    Science.gov (United States)

    Shanina, Violetta; Smolyakov, Pavel; Parfenov, Oleg

    2016-04-01

    The paper deals with the physical and mechanical properties sediment thermal fields Mutnovsky, Lower Koshelevo and Bannyh (Kamchatka). This multi-component soils, mineral and chemical composition of which depends on the formation factors (pH, temperature, salinity of water, composition and structure of the host volcanic rocks). Samples Lower Koshelevo sediment thermal sources differ in the following composition: smectite, kaolinite, kaolinite-smectite mixed-mineral. Samples of sediment thermal springs Mutnovsky volcano in accordance with the X-ray analysis has the following composition: volcanic glass, crystalline sulfur, plagioclase, smectite, illite-smectite mixed, illite, chlorite, quartz, cristobalite, pyrite, melanterite, kaolinite. Natural moisture content samples of sediment thermal springs from 45 to 121%, hygroscopic moisture content of 1.3 to 3.7%. A large amount of native sulfur (up to 92%) and the presence of amorphous material gives low values of density of solid particles (up to 2.1 g/cm3) samples Mutnovskii thermal field. The values of the density of solids sediment Koshelevo and Bannyh hot springs close to those of the main components of mineral densities (up to 2.6-3.0 g/cm3). The results of the particle size distribution and microaggregate analysis of sediment thermal springs Lower Koshelevo field shows that the predominance observed of particles with a diameter from 0.05 mm to 0.25 mm, the coefficient of soil heterogeneity heterogeneous. In the bottom sediments of the thermal springs of the volcano Mutnovsky poorly traced predominance of one faction. Most prevalent fraction with particle size 0.01 - 0.05 mm. When analyzing the content in the soil microaggregates their content is shifted towards particles with a diameter of 0.25 mm. The contents of a large number of large (1-10 mm), porous rock fragments, due to the deposition of pyroclastic material from the eruptions of the last century. Present in large amounts rounded crystals of native sulfur

  17. Analysis of the temperature dependence of the thermal conductivity of insulating single crystal oxides

    Directory of Open Access Journals (Sweden)

    E. Langenberg

    2016-10-01

    Full Text Available The temperature dependence of the thermal conductivity of 27 different single crystal oxides is reported from ≈20 K to 350 K. These crystals have been selected among the most common substrates for growing epitaxial thin-film oxides, spanning over a range of lattice parameters from ≈3.7 Å to ≈12.5 Å. Different contributions to the phonon relaxation time are discussed on the basis of the Debye model. This work provides a database for the selection of appropriate substrates for thin-film growth according to their desired thermal properties, for applications in which heat management is important.

  18. Thermal formation of mesoporous single-crystal Co3O4 nano-needles and their lithium storage properties

    KAUST Repository

    Lou, Xiong Wen

    2008-01-01

    In this work, we report the simple solid-state formation of mesoporous Co3O4 nano-needles with a 3D single-crystalline framework. The synthesis is based on controlled thermal oxidative decomposition and re-crystallization of precursor β-Co(OH)2 nano-needles. Importantly, after thermal treatment, the needle-like morphology can be completely preserved, despite the fact that there is a large volume contraction accompanying the process: β-Co(OH)2 → Co3O 4. Because of the intrinsic crystal contraction, a highly mesoporous structure with high specific surface area has been simultaneously created. The textual properties can be easily tailored by varying the annealing temperature between 200-400 °C. Interestingly, thermal re-crystallization at higher temperatures leads to the formation of a perfect 3D single-crystalline framework. Thus derived mesoporous Co3O4 nano-needles serve as a good model system for the study of lithium storage properties. The optimized sample manifests very low initial irreversible loss (21%), ultrahigh capacity, and excellent cycling performance. For example, a reversible capacity of 1079 mA h g-1 can be maintained after 50 cycles. The superior electrochemical performance and ease of synthesis may suggest their practical use in lithium-ion batteries. © The Royal Society of Chemistry 2008.

  19. Crystal structure of bis(fluorosulfato-κOxenon(II, Xe(SO3F2

    Directory of Open Access Journals (Sweden)

    Moritz Malischewski

    2015-04-01

    Full Text Available Thermally unstable Xe(SO3F2 has been prepared by the reaction of XeF2 with HSO3F. Single crystals were obtained from HSO3F by slow cooling in a sealed tube. The molecular structure is characterized by the Xe atom covalently bonded to two O atoms of two fluorosulfate tetrahedra in an almost linear fashion [O—Xe—O = 179.13 (4°]. The crystal packing is strongly influenced by intermolecular van der Waals forces.

  20. Thermal Conductance of a Surface Phonon-Polariton Crystal Made up of Polar Nanorods

    Science.gov (United States)

    Ordonez-Miranda, Jose; Joulain, Karl; Ezzahri, Younes

    2017-02-01

    We demonstrate that the energy transport of surface phonon-polaritons can be large enough to be observable in a crystal made up of a three-dimensional assembly of nanorods of silicon carbide. The ultralow phonon thermal conductivity of this nanostructure along with its high surface area-to-volume ratio allows the predominance of the polariton energy over that generated by phonons. The dispersion relation, propagation length, and thermal conductance of polaritons are numerically determined as functions of the radius and temperature of the nanorods. It is shown that the thermal conductance of a crystal with nanorods at 500 K and diameter (length) of 200 nm (20 μm) is 0.55 nW·K-1, which is comparable to the quantum of thermal conductance of polar nanowires.

  1. Thermal behaviour of helium-implanted spinel single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Velisa, G., E-mail: gihan@tandem.nipne.ro [National Institute for Physics and Nuclear Engineering - ' Horia Hulubei' , 407 Atomistilor St., P.O. Box MG-6, 077125 Magurele-Ilfov (Romania); Debelle, A. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, UMR8609, Bat. 108, 91405 Orsay (France); Vincent, L. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, UMR8609, Bat. 108, 91405 Orsay (France); Institut d' Electronique Fondamentale, Universite Paris-Sud, UMR8622, Bat. 220, 91405 Orsay (France); Thome, L. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, UMR8609, Bat. 108, 91405 Orsay (France); Declemy, A. [Institut Pprime, Departement de Physique et Mecanique des Materiaux, CNRS-Universite de Poitiers-ENSMA, BP 30179, 86962 Futuroscope-Chasseneuil Cedex (France); Pantelica, D. [National Institute for Physics and Nuclear Engineering - ' Horia Hulubei' , 407 Atomistilor St., P.O. Box MG-6, 077125 Magurele-Ilfov (Romania); Antohe, S. [Faculty of Physics, University of Bucharest, 405 Atomistilor, P.O. Box MG-11, 077125 Magurele-Ilfov (Romania)

    2011-09-01

    The study of the microstructural modifications induced in spinel implanted with {sup 4}He{sup +} at 4.7 at.% and subsequently annealed at 1075 K is addressed in this paper. The combination of three analysis techniques Rutherford backscattering spectrometry in channeling geometry (RBS/C), X-ray diffraction and transmission electron microscopy was used in order to gain information about the damage depth distribution, the nature of radiation defects, and the occurrence of microstructural modifications. In as-implanted crystals the disorder level is weak, and the damage principally consists of small helium-vacancy clusters. These defects induce a tensile strain in the direction normal to the implanted crystal surface. After annealing, a surprising increase of the disorder level is measured by RBS/C. This increased backscattering yield is due to the formation of a particular type of He-vacancy clusters, namely He platelets, which also induce a relaxation of the strain.

  2. Construction of crystal structure prototype database: methods and applications.

    Science.gov (United States)

    Su, Chuanxun; Lv, Jian; Li, Quan; Wang, Hui; Zhang, Lijun; Wang, Yanchao; Ma, Yanming

    2017-04-26

    Crystal structure prototype data have become a useful source of information for materials discovery in the fields of crystallography, chemistry, physics, and materials science. This work reports the development of a robust and efficient method for assessing the similarity of structures on the basis of their interatomic distances. Using this method, we proposed a simple and unambiguous definition of crystal structure prototype based on hierarchical clustering theory, and constructed the crystal structure prototype database (CSPD) by filtering the known crystallographic structures in a database. With similar method, a program structure prototype analysis package (SPAP) was developed to remove similar structures in CALYPSO prediction results and extract predicted low energy structures for a separate theoretical structure database. A series of statistics describing the distribution of crystal structure prototypes in the CSPD was compiled to provide an important insight for structure prediction and high-throughput calculations. Illustrative examples of the application of the proposed database are given, including the generation of initial structures for structure prediction and determination of the prototype structure in databases. These examples demonstrate the CSPD to be a generally applicable and useful tool for materials discovery.

  3. Construction of crystal structure prototype database: methods and applications

    Science.gov (United States)

    Su, Chuanxun; Lv, Jian; Li, Quan; Wang, Hui; Zhang, Lijun; Wang, Yanchao; Ma, Yanming

    2017-04-01

    Crystal structure prototype data have become a useful source of information for materials discovery in the fields of crystallography, chemistry, physics, and materials science. This work reports the development of a robust and efficient method for assessing the similarity of structures on the basis of their interatomic distances. Using this method, we proposed a simple and unambiguous definition of crystal structure prototype based on hierarchical clustering theory, and constructed the crystal structure prototype database (CSPD) by filtering the known crystallographic structures in a database. With similar method, a program structure prototype analysis package (SPAP) was developed to remove similar structures in CALYPSO prediction results and extract predicted low energy structures for a separate theoretical structure database. A series of statistics describing the distribution of crystal structure prototypes in the CSPD was compiled to provide an important insight for structure prediction and high-throughput calculations. Illustrative examples of the application of the proposed database are given, including the generation of initial structures for structure prediction and determination of the prototype structure in databases. These examples demonstrate the CSPD to be a generally applicable and useful tool for materials discovery.

  4. Thermal-capillary analysis of Czochralski and liquid encapsulated Czochralski crystal growth. II - Processing strategies

    Science.gov (United States)

    Derby, J. J.; Brown, R. A.

    1986-01-01

    The pseudosteady-state heat transfer model developed in a previous paper is augmented with constraints for constant crystal radius and melt/solid interface deflection. Combinations of growth rate, and crucible and bottom-heater temperatures are tested as processing parameters for satisfying the constrained thermal-capillary problem over a range of melt volumes corresponding to the sequence occuring during the batchwise Czochralski growth of a small-diameter silicon crystal. The applicability of each processing strategy is judged by the range of existence of the solution, in terms of melt volume and the values of the axial and radial temperature gradients in the crystal.

  5. Molecular and Crystal Structures of Three Berberine Derivatives

    OpenAIRE

    Jiří Dostál; Zdirad Žák; Marek NeÄÂas; Milan PotáÄÂek; Stanislav Man

    2001-01-01

    Berberine azide, berberine thiocyanate, and 8-cyano-8H-berberine were prepared from berberine chloride, a quaternary protoberberine alkaloid. The molecular and crystal structures of all compounds are reported and discussed.

  6. Determination of channeling perspectives for complex crystal structures

    Energy Technology Data Exchange (ETDEWEB)

    Allen, W.R.

    1993-03-01

    Specification of the atomic arrangement for axes and planes of high symmetry is essential for crystal alignment using Rutherford backscattering and for studies of the lattice location of impurities in single crystals. By rotation of an inscribed orthogonal coordinate system, a visual image for a given perspective of a crystal structure can be specified. Knowledge of the atomic arrangement permits qualitative channeling perspectives to be visualized and calculation of continuum potentials for channeling. Channeling angular-yield profiles can then be analytically modeled and, subsequently, shadowing by host atoms of positions within the unit cell predicted. Software to calculate transformed atom positions for a channeling perspective in a single crystal are described and illustrated for the spinel crystal structure.

  7. Growth, structural and optical characterization of L-histidine 4-nitrophenolate (LHPNP) single crystals for NLO applications

    Energy Technology Data Exchange (ETDEWEB)

    Mahadevan, M., E-mail: devanphysics@gmail.com [Department of Physics, Adhiparasakthi Engineering College, Melmaruvathur - 603319 (India); Ramachandran, K., E-mail: ramach76@yahoo.com [Department of Physics, SRM University - Vadapalani Campus, Chennai -600026 (India); Anandan, P., E-mail: anandantcet@gmail.com [Department of Physics, Thiruvalluvar College of Engineering and Technology, Vandavasi-604 505, India and Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-Ku, Hamamatsu 432-8011 (Japan); Arivanandhan, M., E-mail: arivucz@gmail.com, E-mail: royhaya@ipc.shizuoka.ac.jp; Hayakawa, Y., E-mail: arivucz@gmail.com, E-mail: royhaya@ipc.shizuoka.ac.jp [Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka-Ku, Hamamatsu 432-8011 (Japan)

    2014-10-15

    Using slow evaporation solution growth technique, single crystals of L-histidine-4-nitro phenolate has been grown from the solution. Structural analyses were carried out by powder x-ray diffraction, FT-Raman, Fourier Transform Infrared and Nuclear Magnetic Resonance spectral methods to conform the grown crystals. Thermal stability of the grown crystals was studied by thermo-gravimetric (TG) and differential thermal analyses (DTA). UV-Vis spectral analysis has been carried out to find the transparency of the grown crystal. Nonlinear optical property has been confirmed by Kurtz powder technique. The PL measurements were carried out in Perkin Elmer LS 55 Luminescence spectrometer using 410 nm as excitation wavelength. The observed properties have confirmed that the grown crystal is suitable for nonlinear optical applications.

  8. Improving nanocavity switching using Fano resonances in photonic crystal structures

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Kristensen, Philip Trøst; Elesin, Yuriy;

    2013-01-01

    We present a simple design for achieving Fano resonances in photonic crystal coupled waveguide-cavity structures. A coupled mode theory analysis shows an order of magnitude reduction in switching energy compared to conventional Lorentz resonances.......We present a simple design for achieving Fano resonances in photonic crystal coupled waveguide-cavity structures. A coupled mode theory analysis shows an order of magnitude reduction in switching energy compared to conventional Lorentz resonances....

  9. Crystal structure of S-(4-methylbenzyl piperidinedithiocarbamate

    Directory of Open Access Journals (Sweden)

    Z. A. Rahima

    2015-09-01

    Full Text Available The title compound, C14H19NS2, crystallizes in the thione form with the presence of a C=S bond. The piperidine ring adopts a chair conformation. The dihedral angle between the essentially planar dithiocarbamate and p-tolyl fragments is 74.46 (10°

  10. Allophycocyanin and phycocyanin crystal structures reveal facets of phycobilisome assembly.

    Science.gov (United States)

    Marx, Ailie; Adir, Noam

    2013-03-01

    X-ray crystal structures of the isolated phycobiliprotein components of the phycobilisome have provided high resolution details to the description of this light harvesting complex at different levels of complexity and detail. The linker-independent assembly of trimers into hexamers in crystal lattices of previously determined structures has been observed in almost all of the phycocyanin (PC) and allophycocyanin (APC) structures available in the Protein Data Bank. In this paper we describe the X-ray crystal structures of PC and APC from Synechococcus elongatus sp. PCC 7942, PC from Synechocystis sp. PCC 6803 and PC from Thermosynechococcus vulcanus crystallized in the presence of urea. All five structures are highly similar to other PC and APC structures on the levels of subunits, monomers and trimers. The Synechococcus APC forms a unique loose hexamer that may show the structural requirements for core assembly and rod attachment. While the Synechococcus PC assembles into the canonical hexamer, it does not further assemble into rods. Unlike most PC structures, the Synechocystis PC fails to form hexamers. Addition of low concentrations of urea to T. vulcanus PC inhibits this proteins propensity to form hexamers, resulting in a crystal lattice composed of trimers. The molecular source of these differences in assembly and their relevance to the phycobilisome structure is discussed.

  11. Crystal structure, spectrum character and explosive property of a new cocrystal CL-20/DNT

    Science.gov (United States)

    Liu, Ke; Zhang, Gao; Luan, Jieyu; Chen, Zhiqun; Su, Pengfei; Shu, Yuanjie

    2016-04-01

    A new cocrystal explosive of 2,4,6,8,10,12-hexanitrohexaazaiso-wurtzitane(CL-20) and 2,5-dinitrotoluene(DNT) in a molar ratio of 1:2 has been prepared by slow solvent evaporation method. Crystal structure of the cocrystal characterized by single crystal X-ray diffraction (SXRD) reveals that the cocrystal is formed by intermolecular hydrogen bond interactions and belongs to the triclinic system with P-1 group. Moreover, the obivious differences of powder X-ray diffraction (PXRD) patterns, infrared spectroscopy and Raman spectroscopy confirm that the intermolecular interactions have great influence for the crystal structure and formation of cocrystal. The cocrystal exhibits a lower impact height of 44 cm, suggesting a substantial reduction of sensitivity in comparison with CL-20. And thermal test results showed cocrystal obtains a lower melting point than DNT, which means huge advantages in blasting engineering.

  12. Study on temperature property of band structures in onedimensional photonic crystals

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Using transfer matrix method, the optical transmission properties in one-dimensional (1-D) photonic crystal is analyzed.When the temperature varies, not only the refractive index of the optical medium is changed because of the thermo-optical effect, but also the thickness of the optical medium is changed due to the thermal-expansion effect. Thus, the structure of 1/4 wave-plate stack in original photonic crystal is destroyed and the band structure varies. In this work, the effects of the temperature variation on the first and second band gap in a 1-D photonic crystal are analyzed in detail. It is found that the changes of the starting wavelength, the cut-off wavelength and the forbidden band width depend linearly on the temperature.

  13. Surface induces different crystal structures in a room temperature switchable spin crossover compound.

    Science.gov (United States)

    Gentili, Denis; Liscio, Fabiola; Demitri, Nicola; Schäfer, Bernhard; Borgatti, Francesco; Torelli, Piero; Gobaut, Benoit; Panaccione, Giancarlo; Rossi, Giorgio; Degli Esposti, Alessandra; Gazzano, Massimo; Milita, Silvia; Bergenti, Ilaria; Ruani, Giampiero; Šalitroš, Ivan; Ruben, Mario; Cavallini, Massimiliano

    2016-01-01

    We investigated the influence of surfaces in the formation of different crystal structures of a spin crossover compound, namely [Fe(L)2] (LH: (2-(pyrazol-1-yl)-6-(1H-tetrazol-5-yl)pyridine), which is a neutral compound thermally switchable around room temperature. We observed that the surface induces the formation of two different crystal structures, which exhibit opposite spin transitions, i.e. on heating them up to the transition temperature, one polymorph switches from high spin to low spin and the second polymorph switches irreversibly from low spin to high spin. We attributed this inversion to the presence of water molecules H-bonded to the complex tetrazolyl moieties in the crystals. Thin deposits were investigated by means of polarized optical microscopy, atomic force microscopy, X-ray diffraction, X-ray absorption spectroscopy and micro Raman spectroscopy; moreover the analysis of the Raman spectra and the interpretation of spin inversion were supported by DFT calculations.

  14. Synthesis and crystal structures of coordination compounds of pyridoxine with zinc and cadmium sulfates

    Science.gov (United States)

    Furmanova, N. G.; Berdalieva, Zh. I.; Chernaya, T. S.; Resnyanskiĭ, V. F.; Shiitieva, N. K.; Sulaĭmankulov, K. S.

    2009-03-01

    The pyridoxine complexes with zinc and cadmium sulfates are synthesized. The IR absorption spectra and thermal behavior of the synthesized compounds are described. Crystals of the [ M(C8H11O3N)2(H2O)2]SO4 · 3H2O ( M = Zn, Cd) compounds are investigated using X-ray diffraction. In the structures of both compounds, the M atoms are coordinated by the oxygen atoms of the deprotonated OH group and the CH2OH group retaining its own hydrogen atom, as well as by two H2O molecules, and have an octahedral coordination. The nitrogen atom of the heterocycle is protonated, so that the heterocycle acquires a pyridinium character. The cationic complexes form layers separated by the anions and crystallization water molecules located in between. The structural units of the crystals are joined together by a complex system of hydrogen bonds.

  15. Effect of amino acid dopants on the spectral, optical, mechanical and thermal properties of potassium acid phthalate crystals for possible optoelectronic and frequency doubling applications

    Science.gov (United States)

    Prakash, J. Thomas Joseph; Gnanaraj, J. Martin Sam; Dhavud, S. Shek; Ekadevasena, S.

    2015-09-01

    Undoped and amino acid (L-Arginine and L-Valine) doped KAP crystals were grown by slow evaporation solution growth technique. The changes in the structural, spectral, optical, mechanical and thermal properties were observed. The sharp prominent peaks in the indexed powder XRD pattern confirms the crystalline nature of the sample. Optical studies reveal that the crystal is transparent in the entire visible light region. Thermal stability was checked by TG/DTA analysis. The mechanical stability was evaluated from Vicker's microhardness test. The SHG efficiency for the title materials was tested with different particle sizes by the Kurtz and Perry powder method, which established the existence of phase matching.

  16. Icosahedral symmetry described by an incommensurately modulated crystal structure model

    DEFF Research Database (Denmark)

    Wolny, Janusz; Lebech, Bente

    1986-01-01

    A crystal structure model of an incommensurately modulated structure is presented. Although six different reciprocal vectors are used to describe the model, all calculations are done in three dimensions making calculation of the real-space structure trivial. Using this model, it is shown that both...

  17. Synthesis, structural, optical and thermal studies on 3, 5-diethyl-2, 6-di (4-fluorophenyl)-4-oxopiperidinium chloride

    Science.gov (United States)

    Yuvaraj, V.; NizamMohideen, M.; Arockia doss, M.; Rajarajan, G.; Savithiri, S.; Murugakoothan, P.

    2017-02-01

    A new organic compound 3, 5-diethyl-2, 6-di (4-fluorophenyl)-4-oxopiperidinium chloride (DFOC) was synthesized and its crystal was grown from ethanolic solution adopting the slow evaporation solution growth technique. The structure of the grown crystal was analyzed by single crystal X-ray diffraction study. The compound crystallizes in the orthorhombic system with space group Pnma. 1H and 13C Fourier transform nuclear magnetic resonance spectra of DFOC were recorded to elucidate its molecular structure. UV-vis-NIR spectral study showed that the grown crystal is transparent in the entire visible region with the lower cut-off wavelength of 269 nm. The thermal stability of DFOC was studied by thermogravimetric and differential thermal (TG-DTA) analyses.

  18. Thermal dispersion and secondary crystallization of phase change memory cells

    Science.gov (United States)

    Deng, Y. F.; Li, Z.; Peng, J. H.; Liu, C.; Miao, X. S.

    2013-12-01

    The heat accumulation effect associated with heat dispersion process in phase change memory cell was analyzed. The pulse operating scheme was optimized. The pulse sequences with different intervals show distinct heat accumulation effect. A compact model with pulse sequence expansion was proposed, and the simulation result is close to the experiment data for a pulse sequence with interval 20 ns. The simulated R-V curves show that threshold voltage reduces with the decreasing pulse interval. The secondary crystallization and amorphization were used to explain the heat accumulation effect for high speed operation, cycling, and so on.

  19. Crystallization and thermal properties of Polylactide/Palygorskite composites

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2014-06-01

    Full Text Available properties, clay John Wiley & Sons, Inc. Journal of Applied Polymer Science For Peer Review 808x381mm (120 x 120 DPI) Page 1 of 34 John Wiley & Sons, Inc. Journal of Applied Polymer Science For Peer Review Table 1 Films Tg/°C Tc/°C ∆Hm.../Paly (2 wt.%) composite. This decrease in Tcc is an indication of faster crystallization of PLA under the influence of Paly nanoparticles. Sabzi et al.40 recently reported similar results on PLA/ sepiolite composites and found that sepiolite...

  20. Synthesis,Crystal Structure and Thermal Decomposition of Bis[(N-salicylidene-N'-aminoethanol)dioxovandium(Ⅴ)]%水杨醛缩乙醇胺双氧钒席夫碱配合物的合成、晶体结构及热分解研究

    Institute of Scientific and Technical Information of China (English)

    李连之; 许涛; 王大奇; 冀海伟

    2004-01-01

    A new complex bis[(N-salicylidene-N'-aminoethanol)dioxovandium(Ⅴ)], [V(Ⅴ)O2(SALAE)]2, was synthesized by the reaction of salicylaldehyde and aminoethanol with vanadyl sulfate. It was characterized by elemental analysis,IR and X-ray single crystal diffraction analysis. The crystal of the title complex (C18H20N2O8V2, Mr = 494.24) belongs to monoclinic, space group P21/c with the following crystallographic parameters: a = 1.7966(6) nm, b =1.006 mm-1, F(000) =1512, and final R1 = 0.0563, wR2 = 0.1243 for observed reflections 2861(I > 2σ(I)). The complex is a bis(μ-oxo)-bridged V(Ⅴ) schiff base dimer formed by two dioxovandium units, V(Ⅴ) is six-coordinated and forms a distorted octahedral structure. The thermal decomposition for the complex was studied by TG-DTG curves and the apparent activation energy was obtained by the Kissinger formula. CCDC: 211147.