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1.
Abstract  The crystal structures for two of the ligands C6H5CH2SOCH2CONHCH2C6H5 (1) and C6H5SOCH2CON(iC3H7)2 (2) have been determined by X-ray diffraction. These compounds crystallize in orthorhombic system with space groups and cell parameters, Pca21(no. 29), a = 8.4600(5) ?, b = 5.3534(5) ?, c = 32.136(2) ?, V = 1455.42(15) ?3 and Pna21(no. 33) a = 17.5563(11) ?, b = 5.7902(4) ?, c = 14.2866(9) ?, V = 1452.30(16) ?3, respectively. These molecules are stabilized in solid state by various intra and intermolecular hydrogen bonding interactions to give polymeric structures. The reported IR spectra of these compounds in solid state could be explained on the basis of the observed intermolecular hydrogen bonding interactions. Index Abstract  The title compounds C6H5CH2SOCH2CONHCH2C6H5 (1) and C6H5SOCH2CON(iC3H7)2 (2) were prepared by the oxidation of corresponding sulfides with H2O2/SeO2 in methanol and their structures were determined. The structures show that the SO and CO groups are having “anti” configuration in 1 and “syn” configuration in 2. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

2.
The absolute crystal structures of two enantiomorphic forms of the Ca3Ga2Ge4O14 crystals (a = 8.075(1) ?, c = 4.9723(6) ?, space group P321) with the positive and negative senses of the optical activity are determined using X-ray diffraction analysis. The final R factors are as follows: R = 1.75% and R w = 2.57% for the crystal with the positive sense of the optical activity and R = 1.86% and R w = 2.78% for the crystal with the negative sense of the optical activity. The replacement of the Ca2+ ions by larger Sr2+ ions (with the formation of the Sr3Ga2Ge4O14 compound) leads to an anisotropic expansion of the crystal lattice (with a more considerable increase in the lattice parameter a as compared to the lattice parameter c), a change in the occupation of the 1a and 3f positions by the Ga3+ and Ge4+ ions, and symmetrization of the octahedra and tetrahedra forming the structural framework. The shape of the dodecahedron changes so that its size along the polar electric axis 2 increases significantly. This change is the main factor responsible for the increase in the piezoelectric activity of the Sr3Ga2Ge4O14 compound as compared to the piezoelectric activity of the Ca3Ga2Ge4O14 compound. Original Russian Text ? B.V. Mill, A.A. Klimenkova, B.A. Maximov, V.N. Molchanov, D.Yu. Pushcharovsky, 2007, published in Kristallografiya, 2007, Vol. 52, No. 5, pp. 816–823.  相似文献   

3.
Potentiodynamic polarization studies were carried out on virgin specimens of Zr-based bulk amorphous alloys Zr46.75Ti8.25Cu7.5Ni10Be27.5 and Zr65Cu17.5Ni10Al7.5, and conventional-type binary amorphous alloys Zr67Ni33 and Ti60Ni40 in solutions of 0.2 M, 0.5 M and 1.0 M HNO3 at room temperature. The values of the corrosion current density (Icorr) for the bulk amorphous alloy Zr46.75Ti8.25Cu7.5Ni10Be27.5 were found to be comparable with those of Zr65Cu17.5Ni10Al7.5 in 0.2 M and 0.5 M HNO3, but the value of Icorr for the former was almost three times more than that of the latter in 1.0 M HNO3. In the case of conventional binary amorphous alloys, Ti60Ni40 showed lower value of Icorr as compared to Zr67Ni33 in 0.5 M and 1.0 M HNO3 and a comparable value of Icorr in 0.2 M HNO3. In general, the binary Ti60Ni40 displayed the best corrosion resistance among all the alloys in all the cases and the corrosion current density (Icorr) for all the alloys was found to increase with the increasing concentration of nitric acid. It is noticed that the bulk amorphous alloys do not possess superior corrosion resistance as compared to conventional binary amorphous alloys in aqueous HNO3 solutions. The observed differences in their corrosion behavior are attributed to different alloy constituents and composition of the alloys investigated.  相似文献   

4.
The phase separation and crystallization behavior in the system (80 − X)SiO2 · X(Al2O3 + P2O5) · 5B2O3 · 15Na2O (mol%) glasses was investigated. Glasses with X = 20 and 30 phase separated into two phases, one of which is rich in Al2O3-P2O5-SiO2 and forms a continuous phase. Glasses containing a larger amount of Al2O3-P2O5 (X = 40 and 50) readily crystallize and precipitates tridymite type AlPO4 crystals. It is estimated that the phase separation occurs forming continuous Al2O3-P2O5-SiO2 phase at first, and then tridymite type AlPO4 crystals precipitate and grow in this phase. Highly transparent glass-ceramics comparable to glass can be successfully obtained by controlling heat treatment precisely. The crystal size and percent crystallinity of these transparent glass-ceramics are 20-30 nm and about 50%, respectively.  相似文献   

5.
The glass-forming region in the system P---S---Ag was determined and density, thermal expansion, dc conductivity and the transport number of Ag ions were measured for P2S5---Ag2S glasses found in the P---S---Ag system. The results for the transport number measurement show that P2S5---Ag2S glasses are purely ionic conductors owing to the Ag ion migration, like most of the As2S3---Ag2S and GeS2---GeS---Ag2S glasses reported previously. Glass structure and ionic conduction processes in As2S3---Ag2S, GeS2---GeS---Ag2S and P2S5---Ag2S glasses are discussed, based on their ionic conductivity and density data. The structural concept of -Ag2S was applied to these glasses, which suggests that the Ag ions in the glasses are distributed in the available Ag ion sites in the non-conducting framework composed of both S anions and As, Ge or P cations. In each system the ionic conductivity increases linearly with increasing Ag+/total cation (%) in glass composition, the determining factor being the activation energy for ionic conduction alone. Thus, the activation energy in these glasses depends predominantly upon the molar ratio of Ag ions to total cation in the glass, irrespective of the kind of system. Small differences in the activation energy among the three systems can be interpreted as arising from differences in the field strength of As, Ge and P cations.  相似文献   

6.
Glasses in the system Na2O/B2O3/Al2O3/In2O3 were melted and subsequently tempered in the range from 500 to 700 °C. Depending on the chemical composition, various crystalline phases were observed. From samples without Al2O3, In2O3 could not be crystallized from homogeneous glasses, because either spontaneous In2O3 crystallization occurred during cooling, or other phases such as NaInO2 were formed during tempering. The addition of alumina, however, controlled the crystallization of In2O3. Depending on the crystallization temperature applied, the crystallite sizes were in the range from 13 to 53 nm. The glass matrix can be dissolved by soaking the powdered glass in water. This procedure can be used to prepare nano-crystalline In2O3-powders.  相似文献   

7.
NdAl3(BO3)4 single crystals were grown by the flux method and the TSSG technique using a K2O/3MoO3/B2O3/0.5Nd2O3/KF flux system. Light-violet clear crystals could be obtained. The effects of fluoride on the growth of NAB crystals were investigated. As the content of KF was gradually increased, the growth form of NAB was changed from the equant to the columnar and the primary crystalline region of NAB was shrinked. At the ratio of KF/K2O = 0.75, NAB crystals could not be grown.  相似文献   

8.
Q. Qian  G.F. Yang  Z.M. Yang  Z.H. Jiang 《Journal of Non》2008,354(18):1981-1985
Spectroscopic properties of Er3+-doped Na2O-Sb2O3-B2O3-SiO2 glasses have been investigated for developing 1.5-μm broadband fiber amplifiers. An intense 1.5-μm near infrared emission with a broad full width at half maximum (FWHM) of 88 nm has been obtained for Er3+-doped 5Na2O-20Sb2O3-35B2O3-40SiO2 glass upon excitation with a 980 nm laser diode. The obtained emission cross-section of the 4I13/2 → 4I15/2 transition and the lifetime of the 4I13/2 level of Er3+ ions are 6.8 × 10−21 cm2 and 0.36 ms, respectively. It is noted that the product of the emission cross-section and the FWHM of the glass, σe × FWHM, is as great as 598.4 × 10−21 cm2 nm, which is comparable or higher than that of Er3+-doped bismuth-based and tellurite-based glasses. These special optical properties encourage in identifying them as important materials for potential applications in high performance optics and optical communication networks.  相似文献   

9.
Conditions for the flux synthesis of Pb3Ga2Ge4O14 and Ba3Ga2Ge4O14 single crystals and their solid solutions Pb3 − x BaxGa2Ge4O14 are studied. Structural analysis showed that the Ga3+-and Ge4+-cation positions in flux-grown Pb3Ga2Ge4O14 and Ba3Ga2Ge4O14 single crystals are not mixed. __________ Translated from Kristallografiya, Vol. 49, No. 2, 2004, pp. 325–328. Original Russian Text Copyright ? 2004 by Bezmaternykh, Vasil’ev, Gudim, Temerov. This work was presented at the National Conference on Crystal Growth (NCCG-2002, Moscow).  相似文献   

10.
This paper reports on the results of accurate X-ray structural investigations of single crystals La3Ta0.5Ga5.5O14 (a = 8.2260(1) ?, c = 5.1207(1) ?, R/R w = 1.09%/1.10%, 3868 unique reflections) and La3Nb0.5Ga5.5O14 (a = 8.2237(1) ?, c = 5.1247(1) ?, R/R w = 1.02%/1.03%, 3735 unique reflections) (space group P321, Z = 1, sinϑ/λ|max ≈ 1.34 ?−1 for both compounds). Using sets of data with a large number of high-angle reflections makes it possible to reliably compare the crystal structures by applying statistical tests. The structural differences between the La3Ta0.5Ga5.5O14 and La3Nb0.5Ga5.5O14 crystals are weakly pronounced, which correlates with the closeness of their piezoelectric characteristics. Original Russian Text ? A.P. Dudka, B.V. Mill, Yu.V. Pisarevsky, 2009, published in Kristallografiya, 2009, Vol. 54, No. 4, pp. 599–607.  相似文献   

11.
Tomoharu Hasegawa 《Journal of Non》2011,357(15):2857-4499
Glasses of the Bi2O3-TeO2-B2O3 ternary system were developed and their linear and nonlinear optical properties were investigated. The absorption edges of these glasses were found to be 367-384 nm with a good transmittance in visible wavelength, although they exhibit the refractive indices as high as 1.98-2.12 at 633 nm. The absorption edges are quite steep and they are analyzed by the Urbach theory. The obtained Urbach energies of these glasses are 73-79 meV which are comparable to silica glasses. The high refractive index and its glass composition dependency are discussed according to the basics of the electronic polarizability and optical basicity. The high third order nonlinear susceptibility χ(3) = 2.0 × 10− 12 esu at 800 nm was also obtained in the 36Bi2O3-18TeO2-46B2O3 glass.  相似文献   

12.
Reduction in the temperature coefficient of the optical path length, dS/dT of Li2O-Al2O3-SiO2 glass-ceramics with near-zero thermal expansion coefficient was attempted using control of the temperature coefficient of electronic polarizability, ?, and the thermal expansion coefficient, α. The dS/dT value of 2.6 mol% B2O3-doped glass-ceramic was 12.5  × 10−6/°C, which was 0.9 ×  10−6/°C smaller than that of B2O3-free glass-ceramic. On the other hand, reduction in dS/dT through B2O3 doping was not confirmed in precursor glasses. Results showed that reduction in dS/dT of the glass-ceramic through B2O3 doping is caused by the reduction in ?. The reduction in ? from B2O3 doping was probably attributable to numerical reduction in non-bridging oxide ions with larger ? value by the concentration of boron ions in the residual glass phase. In addition, application of hydrostatic pressure during crystallization was effective to inhibit precipitation of β-spodumene solid solution, which thereby decreases dS/dT. The dS/dT value of B2O3-doped glass-ceramic crystallized under 196 MPa was 11.7 ×  10−6/°C. That value was slightly larger than that of silica glass. The α value of this glass-ceramic was smaller than that of silica glass.  相似文献   

13.
采用固相法制备了(0.8 -x)Na0.5 Bi0.5TiO3 -0.2K0.5Bi0.5TiO3-xBaMnO3(简称NBT-KBT-BM)无铅压电陶瓷,研究了不同BM含量(x=0,0.25%,0.50%,0.75%,1.00%,1.25%,物质的量分数)样品的物相组成、显微结构及电性能.结果表明:所制备的NBT-KBT-BM陶瓷样品均为单一的钙钛矿结构.与纯NBT-KBT陶瓷相比,掺BM陶瓷的烧结温度降低,相对密度ρr得到提高.随x的增加,材料的压电常数d33、平面机电耦合系数kp与机械品质因子Qm先增大后减小,而介电损耗tanδ以及退极化温度Td一直降低.BM的掺入降低了材料的矫顽场Ec,提高了剩余极化强度Pr,从而增强了铁电性.当x=0.75%时,陶瓷获得最佳性能:d33=167 pC/N,kp=0.269,Qm=133,εr=774,tanδ=2.93%.  相似文献   

14.
15.
The self diffusion of 62Ni and the shear viscosity in liquid Pd40Ni40P20 and Pd40Cu30Ni10P20 have been measured. The used methods were the long-capillary technique for diffusion measurement and the gas-film-levitation for viscosity measurement. The temperature dependence of diffusion in the equilibrium melt follows the prediction of the mode-coupling theory. The Stokes-Einstein relation describes well the momentum and mass transport in both melts. The 62Ni diffusion is equal in both alloys whereas the normalized bulk viscosity is higher in Pd40Cu30Ni10P20. Thermodynamic and structural considerations are invoked to propose a qualitative explanation for this behavior.  相似文献   

16.
A spherical-shaped model of Al0.20As0.50Te0.30, Al0.10As0.40Te0.50 and Al0.10As0.20Te0.70 amorphous alloys has been performed by the random Monte Carlo method. These models describe quite well the experimental radial distribution functions and abide by the expected coordination numbers apart from the threefold coordinated Te, of which an excess has appeared. The structures are formed, basically, of distorted tetrahedra around the Al atoms whose corners are occupied by As or Te atoms. Also, a separated phase model for Al0.10As0.20Te0.70 alloy has been built taking into account the results of thermodynamical study on this amorphous alloy system. The fitting of this model was better than that of the model generated under the hypothesis of a continuous phase.  相似文献   

17.
An analysis of the atomic radial distribution function of Al0.20As0.30Te0.30, Al0.10As0.40Te0.50 and Al0.10As0.20Te0.70 amorphous alloys obtained from quenching of the molten mixture of the elements was performed. A structure in which all the Al atoms are tetrahedrally bonded to the other types of atoms in the material, would satisfy the requirements of the experimental curve. Tetrahedral groups might be linked to each other by As and Te atoms, or directly through a Te or As atom belonging to more than one tetrahedra.  相似文献   

18.
Abstract  A novel binuclear Smarium (III) complex with N-(2-propionic acid)-salicyloyl hydrazone (C10H10N2O4, H3L) was prepared and characterized. The crystal structure of [Sm2(H2L)2(HL)2(H2O)4] (1) was determined by X-ray single crystal diffractometry. 1 crystallizes in the monoclinic systerm, space group P2(1)/c, with a = 0.10229(2), c = 31.549(7), b = 0.70599(15) nm, and Z = 4. In the structure, Sm(III) is nine-coordinated by carboxyl O and acyl O atoms and imido N atoms of two ligands (H2L and HL forms) and O atoms from two water molecules. H2L and HL act as tridentate ligands which form two stable five-numbered chelating rings sharing one edge in the keto form for each ligand, and the carboxyl groups of two ligands were coordinated via bidentated bridging form. The coordination polyhedron around Sm (III) was described as a monocapped square antiprism. The inter- and intramolecular hydrogen bonds resulted in a three-dimensional network and provided extra stability for the structure. The complex was researched the interaction with calf thymus DNA by electronic absorption titration and emission titration. The results show that the complex is bound to calf thymus DNA mainly by intercalation .The complex also shows good fluorescence property. Index Abstract  The title compound, [Sm2(H2L)2(HL)2(H2O)4] was synthesized by the treatment of N-(2-propionic acid)-salicyloyl hydrazone (C10H10N2O4, H3L) and Sm(NO3) · 4H2O and its crystal structure determined. Single crystal X-ray diffraction analysis reveals that Sm (III) is nine-coordinated by carboxyl O and acyl O atoms and imido N atoms of two ligands (H2L and HL forms) and O atoms from two water molecules. The carboxyl groups of two ligands were coordinated via bidentated bridging form. The coordination polyhedron around Sm (III) was described as a monocapped square antiprism. The inter- and intramolecular hydrogen bonds resulted in a three-dimensional network and provided extra stability for the structure.   相似文献   

19.
The effect of alumina on the phase separation and the crystallization of the glasses of composition (mol%) 18ZnO·30B2O3·52SiO2 and O-40 Al2O3 was studied using an electron microscope and IR spectroscopy. The main crystalline phase appears in the microphase for which the compositions are not nearer to the crystal stoichiometry than the mean. The addition of Al2O3 suppresses the immiscibility but enhances the crystallizability.  相似文献   

20.
Kinetics of the first crystallization stage of Al86Ni2Co5.8Gd5.7Si0.5 amorphous alloy and structure of the partially crystallized specimens were investigated by measurements of electrical resistance, X-ray diffraction and transmission electron microscopy. The presence of Al nanocrystals and eutectic colonies consisted of mutually oriented crystals of Al and metastable phase was found. The transient nucleation and slowing-down diffusion-limited growth and the interface-controlled growth of the quenched-in nuclei were identified as mechanisms of formation of the Al nanocrystals and eutectic colonies, respectively.  相似文献   

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