雨水利用与水量平衡分析在城市园区水景设计中的应用

城市园区水景的水量保障问题对于水景观的建设与运行至关重要,收集雨水资源作为景观用水技术可行、运行经济、符合当前的节水形势。在水景观的设计过程中应用水量平衡分析可以将雨水利用与水景建设统筹考虑,指导水景方案的规划设计,寻求合理的水景规模、高效的水资源利用率,降低水景项目的建设投资与运行费用。将雨水利用和水量平衡分析运用于水景设计中,有利于实现在水资源日益紧缺的形势下水景建设的正常发展。     

浅谈异形柱框架结构的概念设计与要点

近年来,异形柱框架结构（框轻结构体系）,因其能较好地满足建筑使用上和结构性能上的要求,而逐步得到了推广应用,并被列为建设部首批住宅建设新技术推荐目录。但异形柱框架结构设计目前还没有可依据使用的国家标准和行业标准。文章根据对江苏省地方标准《钢筋混凝土异形柱框架结构技术规程》（DB32／512—2002）的理解,结合设计实践经验。浅谈异形柱框架结构和概念设计与要点。     

改进的遗传算法对电液伺服系统PID调节器参数优化方法的研究

遗传算法是一种模拟自然界进化而形成的简单、高效的全局优化算法。本文研究了用改进的遗传算法对某机器人电液位置伺服系统的优化，着重将这种改进后的算法用于PID调节器的参数优化，编制了进化程序，并进行了仿真试验。结果表明用该方法可以有效地解决该电液位置伺服系统PID调节器参数的优化问题。     

Optimization of Welding Process Parameters for 9Cr-1Mo Steel Using RSM and GA

Optimization of A-TIG welding process parameters for 9Cr-1Mo steel has been carried out using response surface methodology (RSM) and genetic algorithm (GA). RSM has been used to obtain the design matrix for generating data on the influence of process parameters on the response variables. A second-order response surface model was developed for predicting the response for the set of given input variables. Then, numerical and graphical optimization was performed using RSM to obtain the target depth of penetration (DOP) and heat-affected zone (HAZ) width using desirability approach. Multiple regression models were developed based on the generated data, and then the models were used in GA to determine the optimum process parameters for achieving the target DOP and HAZ width. GA-based models employed two different selection processes. Both the RSM- and GA-based models suggested a number of solutions in terms of process parameters, and the identified solutions were validated by experiments. GA-based model employing tournament selection has been found to be a more accurate method for determining the optimum A-TIG welding process parameters.     

Determination of Material Parameters of Welded Tube via Digital Image Correlation and Reverse Engineering Technology

Material characteristics play an important role in tube hydroforming (THF). A method, based on digital image correlation (DIC) and reverse engineering (RE) technology, is proposed to determine the material parameters of a welded tube in hydroforming with a single tubular blank. The material parameters of the weld and parent metal are determined by applying membrane theory and the force equilibrium equations, as well as the deformation data which are obtained by DIC and RE technology in the THF process. Finite element simulations of welded THF are performed with these material parameters and the maximum bulge radii and axial profiles of the weld and parent the metal obtained from the simulations are compared with those obtained from the hydroforming experiments to verify the reliability of the proposed method. The results show that the material parameters of the weld are lower than those of the parent metal. With the material parameters adopted in FE simulation there is a good agreement between the simulation and the experiment as for the maximum bulge radii and axial profiles of the weld and parent metal. This verifies that the proposed method is acceptable for determining material parameters of a welded tube.     

Calibration and validation of DEM-FEM model parameters using upscaled particles based on physical experiments and simulations

The real sand is usually idealized by using upscaled particles, due to the large number of particles of tire-sand interaction. This study aims to determine a unique and complete set of DEM-FEM model parameters to improve numerical accuracy of tire-sand interaction after particles idealization. To achieve this aim, a novel method based on experimental design is proposed to calibrate the DEM-FEM model parameters by a series of single-factor numerical calibration tests. Initially, the interaction properties such as equivalent friction coefficients of particle-particle, particle-soil bin and particle-tire are determined successively by comparing experimental test with numerical simulation using the angle of repose as a bulk response. The material parameters of particles are then obtained by modified iteratively to match the stress-strain behavior of the granular assembly in triaxial test. After that, the calibrated parameter set is used to investigate the interaction mechanisms between the off-road tire and the granular terrain. Finally, the simulation results are qualitatively in agreement with the soil bin experiments, which verifies the effectiveness of the calibrated parameter set for the tractive performance analysis of tire-sand interaction.     

Effects of Technical Parameters of Semi-Solid Stirring and Rheo-Rolling on Microstructure of A356–5wt.%B4C Composite Strip

Aluminum boron carbide composite strip was prepared by semi-solid stirring and rheo-rolling, and the effects of process parameters on microstructure of A356–5wt.%B₄C composite strip were studied. The results showed that the distribution of B₄C particles in the matrix became homogeneous, and the average diameter of α-Al and its roundness decreased with the increase of the stirring speed and the stirring time as well as the decrease of the stirring temperature. The average diameter of the primary α-Al grain increased with the increase of the roll speed. When the stirring speed was 500 rpm, the stirring time was 20 min, the stirring temperature was 853 K (580 °C), and the roll speed was 0.2 m/s, the microstructure of A356–5wt.%B₄C composite strip was mainly composed of spherical or rosette α-Al grains, and the distribution of B₄C particles was homogeneous. The hardness of A356–5wt.%B₄C composite strip was 98 HV, and the ultimate tensile strength and elongation were 186 MPa and 1.8%, respectively. The hardness was improved by 25% comparing with casting alloy A356. The ultimate tensile strength and elongation were improved, respectively, by 28.3% and 5.9%.     

Process Development and Product Quality of Micro-Metal Powder Injection Molding

Injection molding has been found to be an efficient and cost-effective manufacturing technique for the production of a wide variety of parts and components at both macro- and microscale. This is attributed to the application of robust design and process development. However, every manufacturing technique is challenged by quality issues and part defects, but tackled by continuous improvement framework(s). This systematic monitoring and control approach of dimensional accuracy, mechanical properties, and surface quality of the finished part strongly depend on process conditions at different production stage. Therefore, the aim of this study is to review process development of micro-metal injection molding; focusing on critical factors influencing part quality and optimization of process parameters. The critical factors that influenced the finished part quality are part design, mold design, material selection, machine, and process conditions. Optimizing mold temperature, melt temperature, injection speed, injection pressure, cooling time, packing, and holding parameters improve the quality of the molded part. This trend of process development of injection molding gave rise to a broad scope of applications with brighter future potentials for the next decades, particularly for medical and electronics applications.     

直流真空断路器换流参数LDW-PSO优化设计方法研究

直流真空断路器(DC VCB)被广泛应于直流输配电系统,但开断时需换流回路强制电流过零实现真空灭弧。换流回路参数直接影响主断路器灭弧能力、弧后鞘层发展速度以及断路器设计成本。本文以有源直流真空断路器为研究对象,结合连续过渡模型建立开断过程各阶段状态方程。考虑多约束条件构建灭弧能力强、弧后鞘层发展速度快和断路器设计成本低的适应度函数;利用权重线性下降PSO算法(LDW-PSO)获得各优化目标下换流电感L和换流电容C参数配置。综合考虑各目标优化配置结果构建最佳适应度函数,并利用LDW-PSO优化得到12 kV/10 kA有源DC VCB的换流参数LC的最佳配置。仿真结果表明,该方法确定的LC参数在确保断路器可靠关断的同时可有效降低断路器的设计成本,达到优化设计目的。     

大型露天矿半连续工艺台阶爆破参数优化试验

针对大型露天矿半连续工艺生产的需求,通过爆破优化试验,运用非连续变形分析、激光机器视觉台阶坡面成像系统、台阶爆破智能设计系统和精确钻孔信息化施工等技术手段,对台阶爆破中孔网参数、装药结构以及延时时间等爆破参数进行优化,有效控制爆堆的前冲和后翻,实现了控制爆堆前冲距离不大于50m、后翻距离不大于15m的优化研究目标。