Study of electron-vibrational interaction and concentration quenching effect of Cu+ ions in lithium based sulphate phosphors

The objective of this work is to study electron-vibrational interaction (EVI) and concentration quenching and their manifestation in experimental photoluminescence spectra of Cu⁺ ion in various lithium based phosphors namely, Li₂SO₄, LiNaSO₄ and LiKSO₄. The main parameters of EVI, such as the Stokes shift, Huang-Rhys factor and zero-phonon line positions, were estimated. The studied systems shows strong electron lattice coupling. The validity of results was established by modeling the shape of the emission spectra, which was found to be in good agreement with experimental photoluminescence spectra. The concentration quenching study is also carried out for these compounds. The studied systems correspond to the nearest neighbor energy transfer mechanism.     

Spherical Periodic Mesoporous Organosilicas Bearing Camphorsulfonamide Substructures for HPLC

New mesoporous organic?Cinorganic spheres were prepared by one step co-condensation of trialkoxysilylated camphorsulfonamide (CSA) and 1,2-bis(triethoxysilyl)ethane (BTSE) using octadecyltrimethylammonium chloride (C₁₈TMACl) as template and ethanol as co-solvent in basic medium. The materials have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), nitrogen sorption measurement, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and elemental analysis (EA). Then the mesoporous organic?Cinorganic spheres were demonstrated to be novel packing materials for potential application in the normal-phase high performance liquid chromatography (HPLC).     

无催化剂条件下微波辐射一步法合成2-氨基-4-芳基-5-氧代-5,6,7,8-四氢-4H-苯并吡喃-3-腈

以芳醛、丙二腈、1,3-环己二酮为原料在无催化剂条件下,分别用微波辐射和传统加热法合成了一系列2-氨基-4-芳基-5-氧代-5,6,7,8-四氢-4H-苯并吡喃-3-腈(4a～4g)衍生物.与常规加热方法相比,微波辐射法具有反应时间短、产率高、后处理方便、环境友好等优点,所有化合物均经IR,1H MMR和元素分析确定.     

Crystallization kinetics of poly(vinylidene fluoride)/MMT,SiO<Subscript>2</Subscript>, CaCO<Subscript>3</Subscript>, or PTFE nanocomposite by differential scanning calorimeter

The nonisothermal crystallization kinetics of poly(vinylidene fluoride) (PVDF) in PVDF/MMT, SiO₂, CaCO₃, or PTFE composites was investigated through differential scanning calorimetry measurements. The enhanced nucleation of PVDF in its nanocomposites with four types of nanoparticle, and their impact on the crystallization kinetics and melting behaviors were discussed. The modified Avrami method and combined Ozawa–Avrami approaches successfully described the primary crystallization of PVDF in nanocomposite samples under the nonisothermal crystallization process. The activation energy was determined according to the Friedman method and it was quite fit with the results of the analysis according to the modified Avrami model and a combined Ozawa–Avrami model.     

Chemical synthesis and optical properties of CdS–poly(lactic acid) nanocomposites and their transparent fluorescent films

This paper describes the first synthesis of cadmium sulfide (CdS)-poly(lactic acid) (PLA) nanocomposites and their transparent fluorescent films by covalently grafting PLA onto the surfaces of CdS nanocrystals (NCs). Synthesis of the nanocomposites involved two steps. Lactic acid (LA)-capped CdS NCs were first prepared by reacting cadmium chloride (CdCl₂) with sodium sulfide (Na₂S) using LA as the organic ligand in H₂O/N,N-dimethylformamide (DMF) solution. CdS–PLA nanocomposites were then formed by in situ ring-opening polymerization of lactide on the surface of modified CdS NCs. We also demonstrated herein the fabrication of the transparent fluorescent films of CdS–PLA nanocomposites by blending as-prepared nanocomposites with high-molecular-weight PLA. The as-prepared CdS NCs and their nanocomposites were studied by transmission electron microscopic imaging, thermogravimetric analyses, and spectroscopic measurements (ultraviolet–visible absorption and photoluminescence). The results revealed that the CdS–polymer nanocomposites exhibited good optical properties in terms of their photoluminescence and transparency.     

Synthesis and microwave dielectric properties of Ca<Subscript>0.6</Subscript>La<Subscript>0.267</Subscript>TiO<Subscript>3</Subscript> nanocrystalline powders by sol–gel method

Ca_0.6La_0.267TiO₃ nanocrystalline powders were successfully synthesized by the sol–gel method using PEG1000 as a dispersant in this study. The sinterability of the powders and the microwave dielectric properties of the ceramics were also investigated. The XRD diffraction result showed that pure Ca_0.6La_0.267TiO₃ powder with orthorhombic perovskite structure could be synthesized at 600 °C for 2 h without any detectable intermediate phase. The average grain size of the as-synthesized powder was as low as 35 nm. Compared with Ca_0.6La_0.267TiO₃ ceramics fabricated by conventional solid-state process, the bulk materials prepared by sintering as-prepared nanopowders performed better in densification and microwave dielectric properties. The ceramics sintered at 1,300 °C exhibited a higher relative density of 98.3% combined with a dielectric constant (ε _r ) of 120.3, a quality factor (Q × f) of 23,550 GHz and a temperature coefficient of resonant frequency (τ _f ) of +220.7 ppm/°C, respectively.     

基于3-甲基-4-对溴苯基-5-(2-吡啶基)-1，2，4-三氮唑的锰配合物的合成和晶体结构

以3-甲基-4-对溴苯基-5-(2-吡啶基)-1,2,4-三氮唑作为配体(L),合成了1个新的锰配合物[MnL2(NCS)2],对其进行了红外、电喷雾质谱和单晶结构表征,该配合物属于单斜晶系,空间群P21/n,a=1.6480(2)nm,b=0.90707(13)nm,c=2.1919(3)nm,β=97.454(2)°,V=3.248 8(8)nm3,Z=4,R1=0.043 9。单晶结构表明,锰离子处于1个扭曲的八面体配位环境中,2个硫氰根离子呈顺式配位,每个配体L通过三氮唑上1个氮原子和吡啶上1个氮原子参与配位。     

两个新的Dowson结构硫钼多酸盐合成，表征以及催化性质

通过水热技术合成了两种新的Dowson结构硫钼多酸盐[C5N2H14]2[S2MoⅥ18O62].8H2O(1)和[C5N2H14]8(H3O)2[S2MoⅤ2MoⅥ16O62]3.(C5H5N)2(2),并通过X射线分析、红外光谱和元素分析其进行了表征。X射线晶体结果分析,化合物1结晶于正交晶系,Pmmn空间群,a=1.79929(17)nm,b=1.35804(13)nm,c=1.41926(13)nm,V=3.4680(6)nm3,Z=2。化合物2结晶于单斜晶系,C2/m空间群,a=2.266 5(3)nm,b=1.374 9(2)nm,c=3.291 2(5)nm,β=104.31(0)°,V=9.938(2)nm3,Z=4。化合物1和2都含有Dawson结构的硫钼多酸阴离子和质子化的N-甲基哌嗪阳离子。并且由苯乙烯的氧化催化结果中看出混价钼的化合物2的催化活性要比化合物1略高。     

CA配合法制备β-Al2O3固体电解质

采用柠檬酸(CA)做还原剂,硝酸盐做氧化剂,利用溶胶凝胶-低温燃烧合成工艺制备了β-Al₂O₃前驱粉料,并利用热分析(TG/DSC)、红外吸收光谱分析(FTIR)、X射线衍射分析(XRD)、扫描电镜(SEM)和交流阻抗谱(EIS)等测试技术对β-Al₂O₃的合成工艺进行了详细的研究。结果表明：该法合成β-Al₂O₃前驱粉料的温度为1 150 ℃,比固相反应法低了150 ℃,平均粒径约为38 nm,具有较好的成型和烧结性能。将素坯在1 630 ℃保温烧结,得到的烧结体相对密度为96%以上,350 ℃时的电导率为0.061 S·cm^-1。     

Pharmacophore Modeling and in Silico Screening Studies to Design Potential KDR Kinase Inhibitors

A novel ligand‐based pharmacophore model for KDR kinase was generated on the basis of chemical features of 30 KDR kinase inhibitors. This pharmacophore model consists of one hydrogen‐bond acceptor, one hydrogen‐bond donor and two hydrophobic groups. Several methods have been used to validate the model, suggesting that it can serve as a reliable tool for virtual screening to facilitate the discovery of novel KDR inhibitors. The model was then used as database search query from the National Cancer Institute (NCI) database for the rational design to identify new hit compound.