直流磁控溅射厚度对Cu(Inx,Ga1-x)Se2背接触Mo薄膜性能的影响

采用直流磁控溅射工艺, 在一定条件下通过控制溅射时间, 在钠钙玻璃上制备了不同厚度的用于Cu(In_x, Ga_1-x)Se₂薄膜太阳电池背接触材料的Mo薄膜, 并利用X射线衍射 (XRD)、场发射扫描电子显微镜 (SEM)、四探针测试仪、台阶仪研究了厚度对溅射时间、薄膜微结构、电学性能及力学性能的交互影响. Mo薄膜的厚度与溅射时间呈线性递增关系; 随厚度的增大, Mo薄膜 (110) 和 (211) 面峰强均逐渐增大, 择优生长从(110)方向逐渐向 (211)方向转变, 方块电阻值只随 (110) 方向上的生长而急剧减小直到一特定值约2 Ω/⇑, 电导率随薄膜的 (110) 择优取向程度的降低而线性减小直到一特定值约0.96×10^-4 Ω·cm; Mo薄膜内部是一种多孔的长形簇状颗粒和颗粒间隙交织的结构, 并处于拉应力态, 其内部应变随薄膜厚度的增大而减小. 关键词： Mo薄膜 CIGS背接触 厚度 微结构     

水体重金属激光诱导击穿光谱定量分析方法对比研究

建立了适用于激光诱导击穿光谱探测的多元线性回归、神经网络回归和支持向量机回归三种定量反演算法模型, 以水体重金属Ni为例进行了回归实验测试和对比分析. 多元线性回归、神经网络回归和支持向量机回归的平均相对标准偏差分别为7.60%, 4.86%, 2.35%; 最大相对标准偏差分别为23.35%, 15.20%, 8.29%; 平均相对误差分别为25.98%, 10.58%, 2.72%, 最大相对误差分别为116.47%, 47.38%, 9.89%. 研究为进一步实现水中痕量金属元素的快速定量分析提供了方法和数据参考. 关键词： 光谱学 激光诱导击穿光谱 支持向量机回归 重金属     

The pressure-induced phase transition of the solid β–HMX

The structural, vibrational and thermodynamic properties of β-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (β–HMX) crystal have been studied using the isothermal-isobaric molecular dynamics (NPT-MD) simulations. The variations of cell volume, lattice constants and molecular geometry of solid β–HMX are presented and discussed at different pressure and temperature. It was found that the N–N bond is significantly lengthened with increasing temperature, which suggests that it is relevant to the initial decomposition. An abrupt change at 27 Gpa for the volume and internal geometrical parameters was observed. This is in good accord with the experimental observation that there is a phase transition at 27 GPa, which is clearly due to conformational change, not chemical reaction. The vibrational frequencies at ambient conditions agree well with experimental results, and the pressure/temperature-induced frequency shifts of these modes are discussed. Frequency discontinuity was also observed at pressure when the phase transition occurred. The Grüneisen parameter was obtained using the vibrational frequency.     

12C6+离子辐照对阿维链霉菌代谢效应研究

对12C6+ 离子辐照诱变高产阿维链霉菌株ZJAV-Y1-203 和原始菌株ZJAV-A-1 的摇瓶发酵pH 值、菌体浓度、碳源和氮源代谢进行了测定,研究了12C6+ 辐照对阿维链霉菌的代谢效应。在发酵前期(48h),原始菌株发酵液pH 值低于突变菌株;在发酵96~196 h,诱变高产菌株ZJAV-Y1-203 繁殖快,生长旺盛,N的利用率高;菌体浓度大于原始菌株的浓度,且发酵液的pH 稳定,菌体处于代谢相对更稳定期;在发酵144~240 h,诱变高产菌株ZJAV-Y1-203 对糖源消耗低于原始菌株ZJAV-A-1。这些结果表明,12C6+ 离子辐照对阿维链霉菌代谢影响有利于阿维菌素合成。pH value, mycelium concentration, carbon source and nitrogen metabolism in flask fermentation of the mutant high-producing strain ZJAV-Y1-203 and the original strain ZJAV-A1 have been investigated, in order to show the metabolic effect of avermitilis irradiated by ion beam of 12C6. In early stage (48 h) of the fermentation, pH value of the original fermentation was lower than that of the mutant strains. In 96~196 h of fermentation, the nitrogen utilization in the strains ZJAV-Y1-203 was higher than that in the original strains, its reproductive was fast, and its growing was vigorous. The mycelium concentration of ZJAV-Y1-203 was greater than the original strain, and the pH value of fermentation were stable, so its metabolism was relatively more stable. In 144240 h of fermentation, the strain ZJAV-Y1-203 on sugar consumption was less than the original strains. The effect of 12C6 ion irradiation on metabolism of Streptomyces avermitilis is conducive to the synthesis of avermectin.     

热中子星r-mode 不稳定性的研究

理论上,不稳定的中子星r-mode 能辐射可探测的引力波。采用具有超软对称能的非对称核物质物态方程,并考虑非牛顿引力效应影响,数值计算了由于CFS(Chandrasekhar-Friedmann-Schutz) 不稳定性引起的年轻热中子星的r-mode 不稳定窗口,给出了引力辐射时标和耗散时标随温度的变化关系。利用中子星观测对非牛顿引力参数的约束,给出了热中子星在高温区不稳定窗口边界的约束,并发现较大的非牛顿引力参数对应着较宽的r-mode 不稳定窗口。研究结果可为地面引力辐射探测提供有意义的参考。Theoritically, instable r-mode in neutron star may radiate detectable gravitational waves. In this work,considering the non-Newtonian gravity proposed in the grand unification theories, we numerically calculate the CFS instabilities of r-mode s in the hot neutron stars by using an equation of state with super-soft symmetry energies. The changes of the gravitational radiation time scales and the viscous time scales versus the stellar temperatures are obtained.And according to the constraint of the neutron star observation on the parameter of non-Newtonian gravity, the constraint on the boundary of the instability window is also given. It is found that a stronger non-Newtonian gravity corresponds with a wider r-mode instability window. These results may provide interesting reference for the gravitational wave detection.     

Investigations of Pulse‐Plasma‐Polymer Coating on TiO2 Nanoparticles and Their Dispersion

An amorphous acrylic acid (AA) polymer coating was generated on TiO₂ nanoparticles through pulse radio frequency (RF) plasma polymerization. The AA plasma synthesis mechanism was studied by its optical emission spectrum. The chemical structures of AA–plasma‐polymer were carefully investigated by Fourier transform infrared spectroscopy (FTIR). The dispersion behaviors of AA‐coated and uncoated TiO₂ nanoparticles in glycol solution were characterized by ultraviolet absorbency and particle size distribution measurements. The results showed that the aggregation of TiO₂ nanoparticles in glycol solution was effectively lowered and the dispersion was improved a lot after AA–plasma‐polymer coating. The pulse plasma coating parameters played an important role in the dispersion enhancement of TiO₂ nanoparticles. By properly regulating the pulse discharge parameters, the system could gain the highest radical–monomer reactions rate, the most compatible functional groups on the nanoparticles, and the best dispersion in the background media.     

Preparation and Characterization of Polypyrrole/Ferrospinel Nanocomposite by W/O Microemulsion Pathway

A polypyrrole/ferrospinel(NiFe₂O₄) nanocomposite was prepared by the in situ chemical oxidizing of pyrrole in the presence of NiFe₂O₄ nanoparticles in water-in-oil (w/o) microemulsion. The structural, morphological, and magnetic properties of the as-prepared polypyrrole/NiFe₂O₄ nanocomposite were characterized by X-ray diffraction (XRD), Fourier transform infrared spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and magnetic measurements. XRD and FTIR revealed the presence of NiFe₂O₄ in the nanocomposite. SEM and TEM images illustrated that polypyrrole was coated on the NiFe₂O₄ surface. The electromagnetic parameters, such as conductivity, saturation magnetization, and coercivity of NiFe₂O₄ nanoparticles varied after coating with polypyrrole.     

Self-Assembled Microfibers of Simple Amphiphilic Molecules Through a Facile Precipitation Route

One-dimensional (1D) fiber structures of simple amphiphilic molecules were prepared through a facile precipitation route. The self-assembly process was studied by ultraviolet-visible absorption and Fourier transform infrared) spectroscopy, which indicated that hydrogen bonding interactions played a role in the1D growth along the axis of the fiber. The water content, self-assembling temperature, and concentration of 1,5-bis-(1-(pyridin-2-yl)ethylidene)thiocarbonohydrazide molecules in the solution had obvious effects on the size and morphology of the self-assembled products. The formation of1D superstructures is not only of a hot subject in the process of nanoscience but also opens a new venue for conveniently controlling self-assembled structures of similar organic molecules.     

Influence of Mixing Technique on Microstructure and Impact Properties of Isotactic Polypropylene/ Poly(Cis-Butadiene) Rubber Blends

Isotactic polypropylene/poly(cis-butadiene) rubber (iPP/PcBR vol%: 80/20) blends were prepared by melt mixing with various mixing rotation speeds. The effect of mixing technique on microstructure and impact property of blends was studied. Phase structure of the blends was analyzed by scanning electron microscopy (SEM). All of the blends had a heterogeneous morphology. The spherical particles attributed to the PcBR-rich phase were uniformly dispersed in the continuous iPP matrix. With increase of the mixing rotation speed, the dispersed phase particle's diameter distribution became broader and the average diameter of the separated particles increased. The spherulitic morphology of the blends was observed by small angle light scattering (SALS). Higher mixing rotation speed led to a more imperfect spherulitic morphology and smaller spherulites. Crystalline structure of the blends was measured by wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS). The introduction of 20 vol% PcBR induced the formation of iPPβ crystals. Higher rotation speed led to a decrease in microcrystal dimensions. However, the addition of PcBR and the increase of mixing rotation speed did not affect the interplanar distance. The long period values were the same within experimental error as PcBR was added or the mixing rotation speed quickened. The normalized relative degree of crystallinity of the blends slightly increased under lower rotation speeds (30 and 45 rpm) and decreased under higher rotation speeds. The notched Izod impact strength of the blends was enhanced as a result of the increase of mixing rotation speed.     

Interaction of Moxifloxacin with Bovine Hemoglobin and Effect of the Coexistent Drugs on the Reaction

The interaction between moxifloxacin (MXFX) and Bovine Hemoglobin (BHb) was investigated at different temperatures by fluorescence spectroscopy. Results showed that the quenching mechanism of MXFX on BHb was a static quenching process with Förester spectroscopy energy transfer. The primary binding for MXFX was located at β-37 Tryptophan residue in hydrophobic cavity of BHb. Besides, weak negative cooperativity was found in drug's binding with BHb. Synchronous spectra revealed that the microenvironment and the conformation of serum albumin were changed during the reaction. Most antibiotics had no effect on the system of BHb-MXFX, except quinolone antibiotics. The system had good stability.