示差脉冲极谱法研究XI. 受前行化学反应控制的电流方程

本文推导了受扩散和前行化学反应控制的示差脉冲极谱电流方程,并用实验进行了验证。根据该方程测得的动力学参数与文献报道值相符合。     

Interfacial Properties of Phosphate Glass Fiber/Poly(caprolactone) System Measured Using the Single Fiber Fragmentation Test

Phosphate glass fiber of the composition 20Na₂O–24MgO–16CaO–40P₂O₅ was produced using an in-house fiber drawing rig. The interfacial properties of the phosphate glass fiber/poly(caprolactone) (PCL) system were measured using the single fiber fragmentation test (SFFT). The system was calibrated using E-glass fibers and polypropylene system. This gave an interfacial shear strength (IFSS) of 4.1 MPa, which agrees well with other published data. The IFSS for the unsized (as drawn) phosphate glass fiber/PCL system was found to be 1.75 MPa. Fibers treated with 3-aminopropyl-triethoxy silane (APS) showed an IFSS of 3.82 MPa. X-ray photoelectron spectroscopic (XPS) analysis of unsized and silane sized fibers established the presence of silane on the fiber surface. Degradation tests of the silane treated fiber/PCL samples were carried out in deionised water at 37°C and it was found that the IFSS values decreased over time. Four others silanes were also investigated but APS gave the highest IFSS values.     

Nanoindentation Experimental Approach and Numerical Simulation of Al/Cr Bilayer Films

The Al/Cr double-layer film structure samples (thickness, 1200 nm) were prepared by the magnetron sputtering method. To investigate the mechanical properties, the samples were measured by using a nanoindentation instrument. The test results showed the nonlinearity and different modes of the main mechanical properties by comparing the macro-scale structure samples with other samples of similar materials. Based on the test, the elastic modulus and hardness of thin film structures can be calculated by considering different loads to conduct multi-point indentations. Meanwhile, the relationships between the mechanical parameters can be investigated based on these Al/Cr double-layer film structure samples. To validate the test, numerical analysis was developed using a finite element method to simulate the loading and unloading process of indentation. The simulation results were compared with the results of experiments to illustrate the validity of both the test and simulation to a certain extent. The investigation builds not only an experimental basis for practical applications for future study, but also supplies a complementary means of verification for theoretical analysis.     

Repulsive Gravitation in the Kerr-Newman Field

It is shown that uncharged test particles, released from rest at infinity in the Kerr-Newman field, stop and rebound when the radial coordinate r takes the value r₀ = Q²/(2M). This expression corresponds to the position of a stationary source of the Kerr-Newman field found by the author. It represents the surface of a massive oblate ellipsoid of revolution undergoing rigid rotation. Besides, the magnitude of r₀ guarantees that no violation of causality occurs throughout spacetime. Although the test particles' angular momenta are always zero, they acquire a rotational motion as a consequence of the dragging of inertial frames.     

Interfacial evaluation of single Ramie and Kenaf fiber/epoxy resin composites using micromechanical test and nondestructive acoustic emission

Interfacial shear strength (IFSS) of environmentally friendly natural fiber reinforced polymer composites plays a very important role in controlling their overall mechanical performance. The IFSS of various Ramie and Kenaf fiber/epoxy composites was evaluated using the combination of micromechanical test and nondestructive acoustic emission (AE) to find the optimal conditions for desirable final performance. Dynamic contact angle was measured for Ramie and Kenaf fibers and correlated the wettability properties with interfacial adhesion. Mechanical properties of Ramie and Kenaf fibers were investigated using single-fiber tensile test and analyzed statistically by both unimodal and bimodal Weibull distributions. The effect of clamping on the real elongation for both Ramie and Kenaf fibers was evaluated as well. Two different microfailure modes, axial dedonding and fibril fracture, coming from fiber bundles and single fiber composites (SFC) were observed under tension and compression. They were evaluated optically and also determined by AE and their FFT analysis nondestructively.     

The Effects of Morphological Properties of Henequen Fiber Irradiated by EB on the Mechanical and Thermal Properties of Henequen Fiber/PP Composites

The aim of this study was to investigate the effects of electron beam (EB) irradiation on the morphological properties, crystallinity and surface area of henequen fiber and on the mechanical and thermal properties of henequen fiber reinforced polypropylene (PP) composites. The structure of henequen fiber was characterized by X-ray diffraction, mercury porosimetry and BET surface area analysis. The EB irradiation of 10 kGy led to the increasing of crystalline and surface pore area of henequen fiber, which contributed to the number of interlocking places with PP. From the results of tensile and impact strength tests, the highest value was observed for the composite reinforced with the henequen fiber treated with EB dose of 10 kGy, decreasing overall as EB dose increased. This tendency was also shown by coefficient of thermal expansion (CTE) measurements, but the value of CTE decreased until 50 kGy, meaning that a large total surface area can provide many interlocking places and so improve adhesion between fiber and matrix. Therefore, it can be concluded that the optimum pore surface area by 10 kGy irradiation contributes to successful mechanical interlocking between fiber and matrix and consequently enhances the mechanical and thermal properties of the composites.     

相转移条件下Cu(Ⅰ)催化的末端炔的偶联反应研究

本文报道端炔与烯(炔)丙基衍生物在Cu(Ⅰ)催化和相转移条件下发生偶联反应合成1,4-烯炔、二炔化合物的方法。考察了溶剂、催化剂、反应底物、反应时间和温度等多种因素对偶联反应的影响, 用正交试验法优选出最佳反应条件,此反应条件具有条件温和、催化剂用量少、收率高、无烯(炔)丙基重排副产物生成等特点。用此方法合成了十一种1,4-烯炔、二炔化合物。     

24－亚甲基胆甾－4－烯－3β，6α－二醇的结构表征

对采用硼氢化钾－乙醇还原4－烯－3，6－二酮类型的甾酮化合物所获得产物 的结构进行了分析，提出了与文献不同的观点。并通过IR，^1H NMR,^13C NMR等谱 图数据对24－亚甲基胆甾－4－烯－3β，6α－二醇进行了结构表征。     

从蓖麻油制取10-羟基癸酸的研究

本文报道了从蓖麻油制取10-羟基癸酸的研究, 发现了从蓖麻油制取10-羟基癸酸的新的工艺路线和最佳的工艺条件, 用氢氧化钠用量、2-辛醇量、反应时间和反应温度四因子三水平L9(3^4)进行了正交试验, 发现最佳工艺条件是: 氢氧化钠(g)/蓖麻油(g):1.25; 2-辛醇量(g)/蓖麻油(g):2; 反应时间:6h; 反应温度:180℃。在这一新的工艺路线和最佳工艺条件下, 10-羟基癸酸产率可达75%。     

Numerical simulation of micro-scratch tests for coating/substrate composites

In this paper the micro-scratch test is simulated by ANSYS finite element code for thin hard coating on substrate composite material system. Coulomb friction between indenter and material surface is considered. The material elastic-plastic properties are taken into account. Contact elements are used to simulate the frictional contact between indenter and material surfaces, as well as the frictional contact after the detachment of coating/substrate interfaces has taken place. In the case of coating/substrate interfaces being perfectly bonded, the distributions of interfacial normal stress and shear stress are obtained for the material system subjected to normal and tangential loading. In the case of considering the detachment of interfaces, the length of interfacial detachment and the redistribution of stresses because of interfacial detachments are obtained. The influences of different frictional coefficients and different indenter moving distances on the distributions of stresses and displacements are studied. In the simulation, the interfacial adhesion shear strength is considered as a main adhesion parameter of coating/substrate interfaces. The critical normal loading from scratch tests are directly related to interfacial adhesion shear strengths. Using the critical normal loading known from experiments, the interfacial adhesion shear strength is obtained from the calculation. When the interfacial adhesion shear strength is known, the critical normal loading is obtained for different coating thicknesses. The numerical results are compared with the experimental values for composite materials of thin TiN coating on stainless steel substrate.