二元Ni-Al合金极端条件下的弹性和热力学性能：全电子准谐波近似 cited: 1)

通过在原子尺度上建模来研究Al、NiAl和Ni₃Al合金在极端高温和高压下的点阵常数、弹性常数、弹性模量、泊松比和弹性各向异性因子等性质．计算得到的弹性常数均满足相应的力学稳定条件．由于NiAl和Ni₃Al具有较高的B=G值,在0～30 GPa内都属于延展性材料．通过包含电子热运动对体系吉布斯自由能贡献的全电子准谐近似方法,得到了高温高压下Al、NiAl和Ni₃Al合金的热膨胀系数、体积模量、热容和熵等．计算值与已有的实验值和理论值符合较好     

Radical 4-exo cyclizations via template catalysis

The mechanism of catalytic 4-exo cyclizations without gem-dialkyl substitution was investigated by a comparison of cyclic voltammetry, EPR, and computational studies with previously published synthetic results. The most active catalyst is a super-unsaturated 13-electron titanocene(III) complex that is formed by supramolecular activation through hydrogen bonding. The template catalyst binds radicals via a two-point binding that is mandatory for the success of the 4-exo cyclization. The computational investigations revealed that formation of the observed trans-cyclobutane product is not possible from the most stable substrate radical. Instead, the most stable product is formed with the lowest energy of activation from a disfavored substrate in a Curtin-Hammett related scenario.     

无皂乳液聚合合成均分散PMMA微球

甲基丙烯酸甲酯;微波辐照;无皂乳液聚合合成均分散PMMA微球     

A Novel Platinum(Ⅳ) Halide Anion as Ethyl-triphenylphosphenonium Salt:Synthetic, Structural and Theoretical Study

A novel platinum(Ⅳ) complex [Ph3PEt]2[PtCl6] 1 obtained from the reaction of H2PtCl6 and [Ph3PEt]I (Ph3PEt+ = ethyl-triphenylphosphenonium) has been structurally characterized.It crystallizes in triclinic, space group P1 with a = 10.20850(10), b = 10.33870(10), c = 10.814 A, α =79.453(12), β = 66.879(11), γ = 72.461(10)°, V= 998.14(9) A3, Z = 1, Dc= 1.648 g/cm3, μ(MoKa) =4.025 mm-1, F(000) = 490, C40H40Cl6P2Pt, Mr = 990.44, the final R = 0.0270 and wR = 0.0617 for 5787 observed reflections with I ＞ 2o(Ⅰ). Structure analysis indicates that the platinum atom almost has the ideal octahedral coordination geometry of PtCl6. The quaternary phosphate cations (Ph3PEt+)acting as counter ions are in combination with PtCl6 anions by static attracting forces and H-bonds.Upon the hydrogen bonds existing between cations and anions, the whole structure represents a chain-like construction. Based on the crystal data, quantum chemistry calculation at the DFT/B3LPY level was carried out to reveal the electronic structure of 1.     

多钒硼酸盐H3{[Cu（en）215[（VO）12O6B18O42]}[B（OH）3]2·16H2O的水热合成、晶体结构和性质

用H3BO3, NH4VO3, Cu(CH3COO)2·H2O和乙二胺在水热条件下合成了新颖结构的多钒硼酸盐H3{[Cu(en)2]5-[(VO)12O6B18O42]}[B(OH)3]2·16H2O,对其进行了单晶X射线衍射、红外光谱、拉曼光谱、紫外-可见漫反射光谱、荧光光谱、顺磁共振谱和热重分析表征.在该化合物的结构中,环状的B18O42通过18个B-(μ3-O)-V键被两个V6O18簇夹在中间,簇阴离子[(VO)12O6B18O42]13-分别通过4个[Cu(en)2]2+与邻近的簇阴离子靠静电相互作用连接成无限二维网状结构,其空洞尺寸为0.619～1.817 nm.     

Effect of boehmite nanorods on the properties of glycidoxypropyl-trimethoxysilane (GPTS) hybrid coatings

AlOOH boehmite nanorods, synthesized by a solid-based process, were incorporated into a sol–gel coating in which GPTS was used as a precursor. Transparent composite coatings with nanorod content up to 40 wt% were obtained by spin coating the sol–gel mixture on glass substrates. Nanorods in the coating were found be aligned parallel to the substrate surface. Mechanical properties, such as modulus and hardness of the nanorod filled coating, were slightly lower than coatings of the same composition but filled with commercially available nanosized boehmite particles. However, crack toughness was greatly improved, as supported by nanoindentation test results. The improvement in crack toughness was attributed to the high aspect ratio of the rigid nanorods, in addition to the fact that the nanorods were aligned within the composite parallel to the surface.     

Research on the fault diagnosis technology of intermittent connection failure belonging to FPGA solder-joints in BGA package

A new method to detect intermittent faults in FPGA (field programmable gate array) of BGA (ball grid array) packages is presented. Inject proper current into measured IO port via sensor circuit, the intermittent faults will arouse impedance of the solder-joint to change intermittently, the voltage of solder-joint will also change intermittently, the fault information can be obtained through regulating the voltage signal. Compared with current monitoring method based on degradation model, this scheme is more reliable and accurate. It can prevent the catastrophic faults caused by failure of the FPGA solder-joints effectively, as well as economize the maintenance cost.