Controlled Synthesis of Ag2S,Ag2Se,and Ag Nanofibers by Using a General Sacrificial Template and Their Application in Electronic Device Fabrication

Nanofiber bundles of Ag₂S, Ag₂Se, and Ag have been successfully synthesized by making use of Ag₂C₂O₄ template nanofiber bundles, utilizing both anion‐exchange and redox reactions. The obtained bundles were polycrystalline nanofibers composed of nanoparticles in which the precursor morphology was well‐preserved, indicating that Ag₂C₂O₄ nanofiber bundles acted as a general sacrificial template for the synthesis of silver‐based semiconductor and metal nanofibers. Dispersing media and transforming reactants were found to be key factors influencing the chemical transformation in the system. In particular, separate single‐crystalline Ag nanofibers were obtained via a nontemplate route when ascorbic acid was used as a relatively weak reductant. An electrical transfer and switching device was built with the obtained Ag₂S and Ag nanofiber bundles, utilizing the unique ion‐conductor nature of Ag₂S and revealing their potential applications in electronics.     

Growth and optical property of zinc oxide thornballs

A new microstructure, thornball, of zinc oxide (ZnO) was synthesized by a very simple solid vapor deposition process under lead oxide (PbO) atmosphere. The microthornballs consist of numerous needles, which extend outwards in all directions symmetrically. They have dimensions of 120 μm in diameter, while the average diameter of the needles is about 100-200 nm. The needles on the balls grow along the 〈0 0 0 1〉 orientation and have gradient compositions along radial. Control experiments proved that PbO played an important role in the growth. Additionally, photoluminescence property was observed and provided the evidence that PbO did not deteriorate the optical properties of ZnO thornballs. This kind of microstructures has potential applications in the field of photochemical catalysis.     

Measurement of metal nanolayers optical parameters using surface plasmon resonance method

The results of experimental definition of optical parameters of silver nanolayers by the method of surface plasmon resonance (SPR) are described. The goniometric installation for measurement of angular dependences of reflection of light by layered nanosructures at the attenuated internal reflection (angular spectrum of reflection) is designed. Calculation of optical parameters of nanolayers is executed taking into account the form of a curve of tin angular spectrum of reflection. The text was submitted by the authors in English.     

Morphology and thermomechanical properties of nanostructured thermosetting blends of epoxy resin and poly(?-caprolactone)-block-polydimethylsiloxane-block-poly(?-caprolactone) triblock copolymer

Poly(?-caprolactone)-block-polydimethylsiloxane-block-poly(?-caprolactone) triblock copolymer (PCL-b-PDMS-b-PCL) was synthesized via the ring-opening polymerization of ?-caprolactone with dihydroxypropyl-terminated PDMS (HTPDMS) as the initiator. The triblock block copolymer was characterized by means of Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). The triblock copolymer was incorporated to prepare nanostructured thermosetting blends. The morphology of the epoxy thermosets containing PCL-b-PDMS-b-PCL were investigated by means of atomic force microscopy (AFM), transmission electronic microscopy (TEM) and small-angle X-ray scattering (SAXS). The thermomechanical properties of the nanostructured blends were investigated by means of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The formation of the nanostructures in the thermosetting composites was judged to follow the self-assembly mechanism in terms of the difference in miscibility of PDMS and PCL subchains with epoxy resin after and before curing reaction.     

Modelling of copper etching in aerated chloride solutions

The effect of dissolved oxygen on the rate of chemical etching of copper by acidic cuprous chloride solution was investigated numerically for the case of a rotating disc electrode (RDE). Copper dissolution in aerated acidic cupric chloride solutions of composition 3.5M CuCl2 + 0.5M HCl + 0.5M KCl and 3.5M CuCl2+0.5M HCl was investigated with consideration of the instantaneous homogeneous reaction 4CuCl32-+4H++O2rlhar4CuCl 3-+2H2O which takes place within the mass transport boundary layer. It was assumed that CuCl32- and O2 react instantaneously, resulting in the formation of a reaction plane which separated the mass transport boundary layer into two regions: a region adjacent to the electrode where oxygen was depleted, and a region adjacent to the bulk where CuCl32- was absent. A one-dimensional mathematical model was developed to predict the position of the reaction plane. The model accounted for diffusion, migration and fluid flow generated by an RDE and included nine species and five heterogeneous electrochemical reactions. The homogeneous redox reaction served to regenerate the chemical etchant solution and thus enhance the etch rate. With increasing oxygen concentration and rotation rate the reaction plane was found to move closer toward the electrode and thus the etch rate of copper increased. Addition of KCl increased the Cl- content in solution so as to shift the reaction plane toward the bulk.     

Electrocatalytic activity of tungsten trioxide microspheres, tungsten carbide microspheres and multi-walled carbon nanotube-tungsten carbide composites

Tungsten trioxide micropheres were prepared by spray pyrolysis, and tungsten carbide microspheres were produced by spray pyrolysis-low temperature reduction and carbonization technology. Multi-walled carbon nanotube-tungsten carbide composites were prepared by the continuous reduction and carbonization process using multi-walled carbon nanotubes (MWCNTs) and WO₃ precursor by molecular level mixing and calcination. The morphology and structure of the samples were characterized by scanning electron microscope and transmission electron microscope. Furthermore, the crystal phase was identified by X-ray diffraction. The electrocatalytic activity of the sample was analyzed by means of methanol oxidation. Tungsten carbide microspheres were catalytic active for methanol oxidation reaction. Nevertheless tungsten trioxide microspheres and multi-walled carbon nanotube-tungsten carbide composites were not catalytic active for methanol oxidation reaction. These results indicate that tungsten carbide micropheres are promising catalyst for methanol oxidation.     

应用一步流动法快速测定土水特征曲线试验研究

实验室常用压力板仪进行常规试验测定粉土土水特征曲线（SWCC）,需耗费数月时间,效率不高。对快速测定粉土SWCC进行了试验研究：采用压力板仪对粉土试样开展一步流动法试验;同时,用Hydrus-1D建立一维水分运移模型;结合模型对干密度为1.78 g/cm3粉土试样中溢出水量随加压时间的关系曲线进行拟合,并得出VG模型中难以实测的参数α和n;根据参数反算出粉土试样SWCC并和压力板仪常规试验的SWCC进行对比。为了消除试验中加载压力过大可能造成的固结对试验结果的影响,还对干密度为1.65 g/cm3的粉土试样进行固结试验使其干密度增大为1.78 g/cm3,再对固结后粉土试样分别进行常规试验和一步流动法试验。对由两种试验得到的固结粉土的SWCC与初始干密度1.78 g/cm3粉土由两种试验实测的SWCC进行了比较。结果表明：① 一步流动法试验拟合的SWCC与常规试验实测的SWCC重合度高;② 一步流动法试验具有快速性和有效性;③ 由Hydrus-1D建立的一维水分运移模型得出的SWCC与常规试验实测的SWCC接近;④ 一步流动法试验结果不会受到固结的影响。     

一维炉系统的测试实验

一维炉是一种研究煤的热解燃烧和结渣等方面的实验系统,可用于模拟电厂煤粉的燃烧特性。以元宝山褐煤为燃料,介绍了一维炉的结构和功能,并对系统的可靠性进行了验证,利用烟气分析仪及热重分析仪对燃烧后的尾部烟气及灰渣进行了分析测定。结果表明:尾部烟气含氧量与灰渣可燃部分剩余量均在理论计算值的误差允许范围内,说明一维炉密封良好,系统内各部分正常运行,对维炉的调试和研究具有一定的参考意义。