重量法测定钨铜合金中钨的质量分数

采用酸溶解试料,用重量法测定钨铜合金中钨的质量分数,滤液中残余的少量钨采用电感耦合等离子体原子发射光谱法（ICP-AES）测定.实验证明该方法具有较高的回收率和精密度,可用于生产实践中.     

双向喇叭形金属网板的共用惰性电极电化学加工法

针对大深径比、双向喇叭形精细金属网板的高效、低成本制造难题,提出了一种电铸-电解组合工艺方法,建立了电铸工艺步骤与电解工艺步骤的电场分析数值模型,利用有限元技术对工艺过程进行模拟仿真。选取优化参数进行工艺试验,并与仿真结果对比,结果证明了仿真的正确性。实验表明,共用惰性电极电化学法可制造大深径比、双向喇叭形精细金属网板。     

Combustion of fine aluminum and magnesium powders in water

Micron-sized metal powders carried by a nitrogen flow were fed along the axis of a cylindrical hydrogen/oxygen diffusion flame. The particles ignited and burned in the water vapor at approximately 2500 K. Experiments were performed at atmospheric pressure. The environment in which particles burned was characterized in detail using computational fluid dynamics. The computations confirmed that the metal powders burned in water while the effect of oxygen and other oxidizing species could be neglected. Combustion was characterized experimentally for micron-sized powders of both aluminum and magnesium. Particle size distributions were measured using low-angle laser light scattering. Optical emission of the burning particles was recorded using filtered photomultiplier tubes. Measured durations of individual particle emission pulses were assumed to represent their burn times; these data were classified into logarithmically spaced time bins. The distribution of the particle burn times was correlated with their size distributions assuming that larger size particles burned longer. It was observed that correlation between the burn times, t, and particle diameters, D, can be approximately described as t ∼ D^0.64 and t ∼ D^0.68 for aluminum and magnesium powders, respectively. The results were compared to previous reports and possible reasons for discrepancies between the present and earlier results were discussed.     

三聚氰胺基螯合树脂的超声合成及在镍离子传感器中的应用

采用超声法制备了三聚氰胺-甲醛-乙二胺四草酰乙酸螯合树脂(MFT)。利用MFT/纳米碳管复合物修饰充蜡石墨电极WGE(MFT/MWCNTs/WGE)制备了一种镍离子传感器。采用场发射扫描电镜及电化学等技术表征了该修饰电极的特性。结果显示,羧基化纳米碳管对MFT螯合树脂具有较强的粘合力,可使该螯合树脂有效地分散,并均匀地吸附在纳米碳管上。MFT/MWCNTs/WGE对镍离子检测效果较好,在1.0×10-11mol/L～1.0×10-10mol/L的浓度范围内,Ni(II)的溶出峰电流与其浓度呈良好的线性增长关系,其线性方程为i(μA)=9.58438+1.07753C x(1×10-11mol/L),R=0.991,检测限为1×10-13mol/L(3σ)。     

Solution of the plane problem for anisotropic media containing an elliptic inhomogeneity with dislocation-like interface

A general form solution of the plane problem for anisotropic media containing an elliptic inhomogeneity with a dislocation-like interface is presented. It is based on the complex series expansion of the stress functions. A general procedure for the determination of coefficients in the series using a continuity condition for the stresses at the imperfect interface and a discontinuity condition for a jump in the normal or tangential displacements at the interface is illustrated. The jump in the displacement components is described by the dislocation-like model based on the assumption that discontinuity of displacement across the interface is linearly proportional to the elastic displacement at the interface in the inhomogeneity. The model can reasonably characterize the imperfect interface from perfect bonding to complete debonding due to separate or combined effect of eigenstrains and far-field tension. Convergence of the results is obtained by truncating a finite number of terms in the series. The present solution is verified with available analytical results for the case of a perfect interface. In this paper, the pattern for the stresses in the heterogeneous anisotropic materials is shown. The effect of imperfect parameters on the distributions of stresses is also discussed. The method and procedure proposed in the paper are useful in analyzing the strength and failure of anisotropic materials containing an inhomogeneity with imperfect interface.     

Interval-parameter robust quadratic programming for water quality management under uncertainty

Effective planning of water quality management is important for facilitating sustainable socio-economic development in watershed systems. An interval-parameter robust quadratic programming (IRQP) method is developed by incorporating techniques of robust programming and interval quadratic programming within a general optimization framework. The IRQP improves upon existing quadratic programming methods, and can tackle uncertainties presented as interval numbers and fuzzy sets as well as their combinations. Moreover, it can deal with nonlinearities in the objective function such that economies-of-scale effects can be reflected. The developed method is applied to a case study of a water quality management under uncertainty. A number of decision alternatives are generated based on the interval solutions as well as the projected applicable conditions. They represent multiple decision options with various environmental and economic considerations. Willingness to accept a low economic revenue will guarantee satisfying the water quality requirements. A strong desire to acquire a high benefit will run the risk of violating environmental criteria.     

IFQP: A hybrid optimization method for filter management in fluid power systems under uncertainty

An interval-fuzzy quadratic programming (IFQP) method is developed for the assessment of filter allocation and replacement strategies in fluid power systems (FPS) under uncertainty. It can directly handle uncertainties expressed as interval values and/or fuzzy sets that exist in the left-hand and right-hand sides of constraints, as well as in the objective function. Multiple control variables are used to tackle independent uncertainties in the model's right-hand sides and thus optimize the overall satisfaction of the system performance. The IFQP method is applied to a case of planning filter allocation and replacement strategies under uncertainty for an FPS with a single circuit. A piecewise linearization approach is firstly employed to convert the nonlinear FPS problem into a linear one. The generated decision alternatives can help decision makers to identify desired policies for contamination control under various total costs, satisfaction degrees, and system-failure risks under different contaminant-ingression/generation rates.     

溶液相制备Ⅱ-Ⅵ族半导体纳米材料研究新进展

Ⅱ-Ⅵ族半导体纳米材料具有特殊的物理化学性质,在光学、电学和光电子等领域都有着巨大的应用前景,因此是纳米材料制备领域的研究热点之一。文章主要综述了近年来溶液相中Ⅱ-Ⅵ族半导体纳米材料制备方法的若干进展情况,并展望了其发展趋势。     

纳米TiO2水性分散浆的制备研究

采用悬浮沉降法研究了几种分散剂对纳米TiO2粉体在水中分散稳定性的影响.结果发现,分散剂种类和用量对粉体的分散性影响很大,将分散剂按一定的比例复配使用,分散效果显著提高.     

The electrodeposition of polypyrrole on Al alloy from room temperature ionic liquids

The direct electrodeposition of conjugated polymers onto active metals such as aluminum and its alloys is complicated by the concomitant oxidation of the metal that occurs at the positive potential required for polymer formation/deposition. We previously described an approach that uses electron transfer mediation to reduce the deposition potential of polypyrrole (PPy) on aluminum and aluminum alloy by nearly 500 mV, permitting film deposition from aqueous solution with nearly 100% current efficiency. In this report, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM⁺TFSI⁻) has been successfully employed both as the growth medium and the supporting electrolyte for directly depositing uniform and conductive PPy coatings onto Al alloy 2024-T3 surface via a potentiodynamic technique. The depositions of PPy were carried out under cyclic voltammetric conditions from 0.3 M pyrrole in ionic liquid solutions. Film morphology was characterized by atomic force microscopy, optical microscopy, and scanning electron microscopy (SEM). Energy dispersive X-ray analysis and X-ray photoelectron spectroscopy verified that the TFSI⁻ anion was incorporated into the polymer as the dopant ion. Thickness of the film was measured by SEM and film conductivity was determined by both a four-point probe technique and by conducting atomic force microscopy. Electrochemical activity of the film was assessed by cyclic voltammetry. Results from these preliminary studies will be reported. Presented at the 2007 FutureCoat! conference, sponsored by the Federation of Societies for Coatings Technology, in Toronto, Ont., Canada, on October 3–5, 2007.