Design optimization of stiffened storage tank for spacecraft

Stiffened storage tank is an important structural component in spacecraft. Its structural weight is one of the key criterions in the design phase. This paper focuses on the design optimization of the structure by using finite element method, structural sensitivity analysis techniques, and sequential linear/quadratic programming aimed to reduce the structural weight. Design variables include the numbers of stiffeners, stiffeners’ section dimensions, and shell thickness distribution. Detailed finite element modeling processes are presented, which are the ways to construct the stiffener (beam orientation and offset) and shell elements and the ways to determine the analysis model and structural boundary conditions. A brief introduction to sensitivity analysis and optimization solution algorithm is also given. Main attention is paid to the studies of design optimization of the tank structure, including the selection of design cases, evaluation, and comparison of the optimal results. There are six design cases considered in the design procedures. Numerical results show that by using the above computational techniques, the structural weight is effectively reduced. In this work, MSC.Patran/Nastran is employed to construct the Finite Element Model (FEM), and JIFEX, which is developed in our group, is used to conduct the structural design optimization. JIFEX is a structural analysis and optimization software package developed by Gu and colleagues in the Dalian University of Technology Department of Engineering Mechanics. Among its many functions is the ability to analyze and optimize piezoelectric smart structures.     

Synthesis of bio-functionalized copolymer particles bearing carboxyl groups via a microfluidic device

Monodisperse copolymer particles carrying surface carboxyl groups in the range of 50–200 μm were prepared by in situ UV polymerization of ethyleneglycol dimethacrylate (EGDMA) with acrylic acid (AA) via a microfluidic flow-focusing device (MFFD). The design of the coaxial orifices in the MFFD enables the confinement of the comonomer liquid thread to the central axis of the microchannel, which can avoid the wetting problem of comonomer liquid with the microchannel and can successfully produce monodisperse copolymer microspheres with coefficient of variance below 5%. The effects of concentration of EGDMA and AA on droplet diameters and the distribution of carboxyl group on particle surfaces were examined. It has been found that, increasing the concentration of AA would decrease particle sizes, but increase the distribution of carboxyl group on particle surfaces. Bioconjugation of the carboxylated copolymer particles with the anti-rabbit IgG–Cy3 conjugates was successfully demonstrated. By increasing the concentration of AA accompanied with decreasing the particle sizes, high efficiency of bioconjugation on carboxylated copolymer particles was achieved. The rapid continuous synthesis of carboxylated copolymer particles via a microfluidic device provides a reliable control of particle sizes and composition for massive production in biotechnological applications.     

煤矿瓦斯监管系统通信子系统的设计

就某矿业集团煤矿瓦斯监管系统通信子系统应具有的功能,文章提出了一种实现方案,描述了通信子系统的组成结构及功能实现流程,分析和制定了通信协议。该通信子系统采用VB设计,利用双向通信方式和数据帧的数据格式以及定时探测的方式,有效地提高了通信系统的性能,为煤矿瓦斯监管系统提供了一个高效可靠的通信平台。     

深海集矿机模型车避障系统设计

考虑深海底集矿机的未知、复杂工作环境以及在集矿机上做试验的不便,设计并实现了深海集矿机模型车避障系统;该系统先用超声波传感器检测障碍物信息,然后用高性能单片机AT89S52对信息进行处理后传送到水下工控机,在此基础上,运用改进势场法进行行走避障,规划出深海集矿机模型车作业路径;此算法适应于动态未知复杂环境下的深海集矿机实时导航和避障,且在目标点附近存在障碍物时也能达到目标;仿真和试验结果验证了该算法的有效性。     

凹印机恒张力控制系统的研究

张力控制技术广泛应用于卷绕类自动化控制系统中,以凹印机为研究对象,详细论述了凹印机系统的张力控制原理;并设计了一套以GE公司的90系列可编程逻辑控制器为控制器,采用工控机监控系统实时状态的张力控制系统;选用西门子公司的WinCC作为系统的组态软件,并采用OPC作为软件接口标准实现GE和西门子两家不同公司产品的数据交换;该方案不仅适合本系统,而且对于这一类放卷、收卷结构的张力控制系统均有一定的参考价值;生产运行表明,该系统运行稳定,控制精度满足要求。     

现代产品设计中“软设计”理念探寻

本文针对产品设计中的"软设计"理念进行诠释和探讨。笔者认为随着社会的发展,科技的进步,设计文化在产品中的渗透,"软设计"理念在产品设计过程中凸显重要。     

当今设计现实的伦理审视

通过分析当今设计领域的伦理缺失现象,从道德层面对由设计带来的金钱至上、道德沦丧、环境污染和资源浪费等问题进行批判,并提出设计要实现以人的关怀为基准的伦理回归。     

新视觉形式:网络数码图形艺术

在网络上传播的数码图形艺术与计算机和网络有着密不可分的关系,它立足于网络交互性和数码造像的特质,带有强烈的数字艺术的特征,也形成了自己特有的时代特征。     

由无意识引发的思考

人们对于弗洛伊德的"无意识"理论中的意识和无意识已经研究了很多,但是关于前意识的研究却很少。本文从无意识入手并与唐纳德.A.诺曼的设计理论相结合,就前意识对设计的重要作用予以肯定并对提出唤醒前意识的方法。     

Urinary proteomic analysis of chronic allograft nephropathy

The pathogenesis of progressive renal allograft injury, which is termed chronic allograft nephropathy (CAN), remains obscure and is currently defined by histology. Prospective protocol-biopsy trials have demonstrated that clinical and standard laboratory tests are insufficiently sensitive indicators of the development and progression of CAN. The study aim was to determine if CAN could be characterized by urinary proteomic data and identify the proteins associated with disease. The urinary proteome of 75 renal transplant recipients and 20 healthy volunteers was analyzed using surface enhanced laser desorption and ionization MS. Patients could be classified into subgroups with normal histology and Banff CAN grades 2-3 with a sensitivity of 86% and a specificity of 92% by applying the classification algorithm Adaboost to urinary proteomic data. Several urinary proteins associated with advanced CAN were identified including α1-microglobulin, β2-microglobulin, prealbumin, and endorepellin, the antiangiogenic C-terminal fragment of perlecan. Increased urinary endorepellin was confirmed by ELISA and increased tissue expression of the endorepellin/perlecan ratio by immunofluoresence analysis of renal biopsies. In conclusion, analysis of urinary proteomic data has further characterized the more severe CAN grades and identified urinary endorepellin, as a potential biomarker of advanced CAN.