High-throughput first-principle calculations of the structural,mechanical, and electronic properties of cubic XTiO3 (X = Ca,Sr, Ba,Pb) ceramics under high pressure

High-throughput first-principle calculations are implemented to study the structural, mechanical, and electronic properties of cubic XTiO₃ (X = Ca, Sr, Ba, Pb) ceramics under high pressure. The effects of applied pressure on physical parameters, such as elastic constants, bulk modulus, Young's modulus, shear modulus, ductile-brittle transition, elastic anisotropy, Poisson's ratio, and band gap, are investigated. Results indicate that high pressure improves the resistance to bulk, elastic, and shear deformation for XTiO₃ ceramics. Pugh's ratios B/G reveal that CaTiO₃ and PbTiO₃ ceramics are ductile, but SrTiO₃ and BaTiO₃ ceramics are brittle under the ground state. The brittle-to-ductile transition pressures are 24.26 GPa for SrTiO₃ and 43.23 GPa for BaTiO₃. Under high pressure, the strong anisotropy promotes the cross-slip process of screw dislocations, and then enhances the plasticity of XTiO₃ ceramics. Meanwhile, XTiO₃ (X = Ca, Sr, Ba) is intrinsically an indirect-gap ceramic, but PbTiO₃ is a direct-gap ceramic. High pressure increases the band gap of XTiO₃ (X = Ca, Sr, Ba) ceramic, but decreases that of PbTiO₃ ceramic. This work is helpful for designing and applying XTiO₃ ceramics under high pressure.     

Ce~（3＋）在钙钛矿型KMF_3（M＝Mg、Ca、Sr、Ba）基质中的发光特性

采用高温固相反应法，在Ａｒ气氛中合成了ＫＭＦ３（Ｍ＝Ｍｇ、Ｃａ、Ｓｒ、Ｂａ）基质化合物和掺杂Ｃｅ３＋的磷光体。经Ｘ射线衍射分析确定，ＫＭｇＦ３和ＫＣａＦ３属于立方晶系、钙钛矿型结构，ＫＳｒＦ３和ＫＢａＦ３具有类似的结构。测定了ＫＭＦ３∶Ｃｅ３＋的发光光谱，观察到与其结构对应的分为二种不同的光谱结构，讨论了Ｃｅ３＋的取代格位     

EFFECTS OF SOME PHENYLETHYNYLSILICON COMPOUNDS ON HEAT-CURABLE SILICONE RUBBER Ⅲ 1, 1, 3, 3-TETRAMETHYL-1, 3-DIPHENYLETHYNYL-DISILOXANE*

We have shown that some phenylethynylsilicon compounds are good cure crosslinkersof heat-curable silicone rubber(HCSR). In this paper the effects of 1, 1, 3, 3-tetramethyl-1, 3-diphenylethynyldisiloxane (TMDPDS) as a crosslinker on HCSR were studied. Thevulcanizates with fine mechanical properties could be obtained with suitable amounts ofTMDPDS. Sol fractions, and crosslinking density of vulcanizates and vulcanizationretardation effect of TMDPDS on hydrosilation curing silicone rubber were also discussed.     

ErCl3—MCln体系相图的研究

借助于DTA与X射线衍射法研究了ErCl_3-MCl_n(M=Li,Ca,Pb;n=1,2)二元体系相图.发现ErCl_3-LiCl体系相图属固液异组成型,有一固液异组成化合物Li_3ErCl_6生成,且在466℃有一相转变.其无变点分别为e 40.0mol(％)ErCl_3(479℃)和p31.0mol(％)ErCl_3(522℃);而ErCl_3-CaCl_2,PbCl_2体系皆属简单低共熔型相图.其低共熔点e分别为:46.0 mol(％)ErCl_3(578℃)和38.0mol(％)ErCl_3(405℃).ErCl_3-PbCl_2体系在固相下有一不稳定化合物PbErCl_5生成,在356℃分解.同时探讨了相图的某些规律.     

Tetraazadibora[3, 3]paracyclophane

Starting from the para‐phenylenediamine derivative HN(SiMe₃)‐C₆H₄‐NH(SiMe₃), a lithiation and subsequent borylation give [(MeO)₂B]N(SiMe₃)‐C₆H₄‐N(SiMe₃)[B(OMe)₂] ( 1 ), the hydridation of which yields Li₂[(H₃B)N(SiMe₃)‐C₆H₄‐N(SiMe₃)(BH₃)] ( 2 ). Applying ZrCl₄ upon 2 initiates a condensation to give the title compound [‐N(SiMe₃)‐p‐C₆H₄‐N(SiMe₃)‐BH‐]₂, a hetero[3, 3]paracyclophane with two N‐B‐N chains that connect the para‐phenylene units. The product 3 crystallizes in the orthorhombic space group P2₁2₁2₁.     

Method/basis set dependence of the traceless quadrupole moment calculation for N2, CO2, SO2, HCl,CO, NH3, PH3, HF,and H2O

Dipole moments and traceless quadrupole moments for a training set of nine molecules—N₂, CO₂, SO₂, HCl, CO, NH₃, PH₃, HF, and H₂O—were deduced from the final optimized density matrices of a series of ab initio calculations, thereby employing different levels of theory with varying basis set quality. All the results were obtained in a true ab initio sense, meaning that at a certain combination of method/basis set, the configurations of the molecules were first subjected to a geometry optimization and only afterwards the dipole and traceless quadrupole moments were derived for the final relaxed structures. All results could be compared to experimental data, thus the quality of the different models with respect to applicability and reliability of calculating molecular moments without any knowledge of structural details of the equilibrium geometries could be evaluated. Generally, a combination of methods that take into account correlation effects, together with a high‐level basis set, was found to yield molecular moments close to the experimental values. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001     

Total Synthesis of Several 3, 3"-Biflavones

BiflavonesareamorecomPlicatedclass0fflavonoids.MostofthemareusefulcomPonentsoftraditionalmedicinetocurediseases.Sincechamaejasminel,anewtoeofbiflavonoidpossessingaC-3/C-3"linkage,wasisolatedfromSteUerachamaejasmaeL.byHuangetal',especiallyafterthebiologicalactivityofani-cancerwasdiscovered',thestUdyof3,3"-biflavonoidshasattfactCdmuchattention.3-5ButtherehasbeennoprogressmentionedonthesynthesisofthiskindofcomPoundsinrecentdecades.AsaresultofoursystematicresearchonthesynthesisofchamaejasInin…     

Facile synthesis of 3-aryl benzofurans, 3-aryl benzothiophenes, 2-aryl indoles and their dimers

The preparation of 3-aryl benzofuran and benzothiophenes and their dimers at 2-position and, 2-aryl indoles and their 3-position dimers preparation is described.     

Ethanol steam reforming over Ni-Cu/Al2O3-MyOz （M = Si, La, Mg, and Zn） catalysts

Ni-based catalysts doped with copper additives were studied on their role in ethanol steam reforming reaction.The effects of Ca content,support species involving Al2O3-SiO2,Al2O3-MgO,Al2O3-ZnO,and Al2O3-La2O3,on the catalytic performance were studied.Characterizations by TPR,XRD,NH3-TPD,XPS,and TGA indicated that catalysts 30Ni5Cu/Al2O3-MgO and 30NiSCu/Al2O3-ZnO have much higher H2 selectivity than 30NiSCu/Al2O3-SiO2,as well as good coke resistance.H2 selectivity for 30Ni5Cu/Al2O3-MgO catalyst was 73.3% at 450℃ and increased to 94.0% at 600 ℃,whereas for 30NiSCu/Al2O3-ZnO catalyst,the H2 selectivity was 63.6% at 450 ℃ and 95.2% at 600 ℃.These Al2O3-MgO and Al2O3-ZnO supported Ni-Cu bimetallic catalysts may have important applications in the production of hydrogen by ethanol steam reforming reactions.     

Structures,Vibrational Spectra,and Relative Energetics of CH3COIO3 Isomers

The structures, vibrational spectra, relative energetics, and enthalpies of formation of CH₃COIO₃ isomers have been investigated with B3LYP, B3P86 and B3PW91 methods in conjugation with the 6‐31+G(d), 6‐311+G(d,p) and 6‐311++G(3df,3pd) basis sets. The CH₃COOIO₂ structure was found to be the most stable form among the isomers with an estimated enthalpy of formation of ?314.6 kJ·mol^?1. The enthalpies of formation for CH₃COOOOI, CH₃COOOIO and CH₃COIO₃ are ?180.7, ?184.9 and ?50.6 kJ·mol^?1, respectively. The implication of the formation of CH₃COIO₃ isomers from the atmospheric cross‐reactions of the acetylperoxy (CH₃COO₂) and iodine monoxide (IO) radicals was examined and the possible dissociation products of the most likely CH₃COIO₃ isomers were determined.     

La-Co-Ce-O复合氧化物催化剂的制备、结构与性能

采用柠檬酸络合法制备出具有不同原子比（La＋Co/La＋Co＋Ce）的La-Co-Ce-O系列复合氧化物，并采用XRD、XPS和H2-TPR等方法对样品进行了表征测试．XRD结果表明，样品中的活性相为高分散的Co3O4纳米微晶（20～50nm）和少量的LaCoO3相，与浸渍法相比，柠檬酸络合法制得的样品具有更高的组分分散度和更小的晶粒度．CO氧化活性测试结果表明，柠檬酸络合法制得的样品比传统浸渍法制得的样品起燃温度降低约40℃，但样品的氧化活性与活性相Co3O4的多少及其晶粒度并不呈顺变关系．TPR和XPS的结果表明，样品中CeO2含量及可还原氧物种的多少与活性有直接关联，样品表面La、Co和Ce的原子百分数接近时，协同效应最佳，活性最好．     

The Chemistry of Tetrafluoroallene： One－pot Synthesis of Trifluoromethylindolizines from 1,3－Diiodo－1,1,3,3－tetrafluoropropane by 1,3－Dipolar Cycloaddition

Heating a mixture of 1, 3-diiodo-1, 1, 3, 3-tetrafluoropropane (2), K2CO3, pyridinium bromides (3) in CH3CN at 65℃ for 10 h gives the corresponding trifluoromethylindolizines.     

3, 6-二取代-均三唑并[3, 4-b]-1, 3, 4-噻二唑的合成

研究了2-苯基-1, 2, 3-三唑-4-羧酸(1)与3-烷基/芳基-4-氨基-5-巯基-1, 2, 4-三唑(2a～o)在POCl~3催化下, 脱水缩合得到15个新的3-烷基/芳基-6-(2'-苯基-1', 2', 3'-三唑-4'-基)均三唑并[3,4-b]-1, 3, 4-噻二唑类化合物(3a～o)。     

N-Trifluoromethyl Hydrazines,Indoles and Their Derivatives

Reported herein is the first efficient strategy to synthesize a broad range of unsymmetrical N-CF₃ hydrazines, which served as platform to unlock numerous currently inaccessible derivatives, such as tri- and tetra-substituted N-CF₃ hydrazines, hydrazones, sulfonyl hydrazines, and valuable N-CF₃ indoles. These compounds proved to be remarkably robust, being compatible with acids, bases, and a wide range of synthetic manipulations. The feasibility of RN(CF₃)-NH₂ to function as a directing group in C−H functionalization is also showcased.     

YbCl3-MCln体系相图的研究(M=Li、Mg、Ca、Pb; n=1,2)

借助于DTA与X射线衍射法研究了YbCl_3-MCl_n(M=Li、Mg、Ca、Pb; n=1或2)二元体系相图．发现YbCl_3-LiCl体系相图属固液异组成型，有化合物Li_3YbCl_6生成，它在481 ℃有一相转变. 其无变点分别为x_(YbCl_s)＝0.410；526 ℃和x_(YbCl_3)=0.340，547 ℃；YbCl_3-MgCl_2属类转熔型相图，在富YbCl_3相区666 ℃有一尚不知其性质的热效应，为x_(YbCl_3)＝0.380，628 ℃；YbCl_3-CaCl_2和YbCl_3-PbCl_2体系皆属简单低共熔型相图，其低共溶点分别为x_(YbCl_3)＝0.530, 615 ℃和x_(YbCl_3)＝0.340, 415 ℃. 后者在固相下有一不稳定化合物PbYbCl_5生成，在392 ℃分解，同时探讨了相图的某些规律．     

Synthesis, Characterization, and Photocatalytic Activity of Bi_2O_3

A series of Bi2O3 were prepared by a facile hydrothermal method using NaOH and ammonia as the mineralizers. The products were characterized by XRD, IR, UV-vis diffuse reflectance spectra, and photodegradation of Rhodamine B dye. Simply using NaOH to supply a strong base condition, single phase α-Bi2O3 was formed. When changing the amount of NaOH and ammonia, mixed phases of α-Bi2O3, （BiO）4CO3（OH）2 and Bi2O2CO3 were obtained. All samples were found to show photocatalytic activities towards the degradation of Rhodamine B dye under UV light irradiation, in which mixed phase samples showed higher activities than single phase α-Bi2O3 possibly owing to the synergistic effect of the mixed phases.     

水热合成稀土氟化物材料KZnF3∶Er, Yb的上转换发光特性

水热法合成了掺杂Er3+和Yb3+的 KZnF3材料, 研究了Er3+和Yb3+在这种基质材料中的吸收和在980 nm红外光激发下的上转换发光, 对比了不同Yb3+浓度(0%～4%)下的上转换发光特性.实验发现, 在同种材料中, Er3+的红光发光强度要明显强于绿光, 而且掺Yb3+后红光和绿光的光强比不掺Yb3+时都有了很明显地增强.当Yb3+浓度为2%时上转换发光光强达到最强, 大于2%后发光开始减弱.通过分析输出光强与泵浦光强的双对数曲线, 发现Er3+的红光和绿光的发射均属于双光子过程, 最后分析了红光和绿光上转换发光的具体过程和转换通道.     

Synthesis of 3-methyl-coumarins, -thiacoumarins and -carbostyrils

Reaction of 3,6-dimethyl-4-phenyl-3,4-dihydrocoumarin5a with anhydrous aluminum chloride gave 3,6-dimethyl-coumarin (6a); likewise, 6-chloro-3-methyl-coumarin (6b) was obtained from5b. Substituted 3-methyl-thiacoumarins (8a,b and 3-methyl-carbostyrils (10a-e) were prepared from the reactions of the respectivea-methyl-cinnamoyl derivatives (7a,b and (9a-e), of thiophenols and anilines.     

Synthesis,spectral, bioactivity,and NLO properties of chalcone metal complexes

A series of metal(II) complexes ML and ML₂ [where M?=?Cu(II), Co(II), Ni(II), Zn(II), Mn(II), Cd(II), and VO(II); L?=?2-hydroxyphenyl-3-(1H-indol-3-yl)-prop-2-en-1-one (HPIP)] have been prepared and characterized by elemental analysis, magnetic susceptibility, molar conductance, IR, UV-Vis, NMR, Mass, and ESR spectral studies. Conductivity measurements reveal that the complexes are non-electrolytes, except VO(II) complex. Spectroscopy and other data show square pyramidal geometry for oxovanadium and octahedral geometry for the other complexes. Redox behavior of the copper(II) and vanadyl complexes has been studied with cyclic voltammetry. Antimicrobial activities against several microorganisms indicate that a few complexes exhibit considerable activity. The nuclease activity shows that the complexes cleave DNA. All synthesized compounds can serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The second harmonic generation efficiency of the ligand is higher than that of urea and KDP.     

Preparation and Electrochemical Properties of 3-Pyridinyl-6-aryl-1, 2, 4-triazolo [3, 4-b][1, 3, 4]thiadiazoles

A series of 3-pyridinyl-6-aryl-1, 2, 4-triazolo[3, 4-b][1, 3, 4]thiadiazoles(PATT) were prepared, the structures were confirmed by 1R and ^1H NMR spectra. The results of cyclic voltammetry measurements imply that all these compounds have a higher electron affinity (EA) than 2-(4-biphenyl)-5-(4-tert-butyl phenyl)-1, 3. 4-oxadiazole (PBD) which implies that PATT could be acting as better electron acceptors than widely used electron transporting material PBD.