提高脉冲响应函数检测精度的研究

结构的单位脉冲响应函数(IRF)检测是一项具有重大理论和实践意义的工作,但是,该项研究远未引起足够的重视。本文在分析频响函数(FRF)实虚部特性的基础上,提出对经典IRF检测方法(FRF富氏逆变换)的两项改进,它们是:补偿修正法和FRF虚部变换法。数值模拟计算和试验数据处理表明,改进方法显著地提高了IRF的检测精度。     

Inverse Opal Scaffolds with an Embossed Surface Pattern Prepared from Sticky Golf‐Ball‐Shaped Microparticle Assemblies

Inverse opal scaffolds presenting an embossed‐pattern surface are prepared from colloidal crystal assemblies of uniformly sized golf‐ball‐shaped microparticles. Post‐treatments, such as thermal annealing during the bridging of the microparticles for opal preparation, are avoided to prevent deterioration of surface patterns of the sacrificial template. This presents a new approach to increase the surface‐area‐to‐volume ratio (SAV) by the alteration of morphological features in sophisticated 3D structures that remain largely unexamined owing to difficulties in their preparation. Previous results observed in 2D surfaces that show effective performance improvement through an increase in contact area, especially in biomedical applications, also appear applicable to patterned inverse opal scaffolds based on comparable results obtained from cell cultures. As the field of application of opal and inverse opal structures is expanding due to their unique structural advantages, such as 3D interconnectivity and periodic structures, our strategy opens the door for the use of patterned surfaces on highly sophisticated 3D structures, improving their performance via an increase in SAV.     

沉井逆作法施工技术

以太原市集中供热联网工程东中环主干线北沙河处的热力小室为例,根据实际情况,对不同施工方案的优缺点进行了分析,经比选,采用井室逆作工艺进行施工,并着重论述了沉井逆作法的施工技术要点,为今后同类工程施工提供了参考依据。     

Formulation and characterization of Brucea javanica oil microemulsion for improving safety

Objective: This study engaged in investigation of optimal formulation, characteristics analysis of Brucea javanica oil microemulsion (BJOM) in order to address safety concerns and make recommendations for improvements in BJOM safety during clinical use in vivo.

Methods: Pseudo-ternary phase diagram techniques were used to determine the appropriate ratio of surfactant, cosurfactant and oil phases. Subsequent stability testing of BJOM was performed by dilution, centrifugation and accelerated stability testing. The results were expounded through additional assessment utilizing the classical thermostat method to establish the shelf life of the material. These results were utilized to evaluate the safety of BJOM by haemolytic, irritative and allergic testing in vitro. In addition, the cytotoxicity of BJOM was examined using the tetrazolium salt 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), with particular emphasis given to potential uses in cancer treatment.

Results: The most suitable method of preparation for BJOM was found to be a one to one ratio (K_m 1:1) of Solutol HS15 surfactant matched with sorbitol cosurfactant in the ratio. The microemulsion droplets of BJOM possessed a spherical shape, uniform size and average diameter of 23.8?nm. The expiration date of BJOM was found to be 568?d. The safety study demonstrated no hemolysis activity at the experimental BJOM concentrations; however, mild hemolysis was observed at higher concentrations of Brucea javanica oil emulsion (BJOE), a common commercially available product. Irritation observed upon BJOM treatment can be primarily attributed to Brucea javanica oil (BJO) with little influence of BJOM excipients. In addition, BJOM caused no observed hypersensitivity or other visible allergic reactions in guinea pigs. The anticancer activity curves of BJOM and BJOE demonstrate that both BJOM and BJOE inhibit Hela cells, with BJOM demonstrating significantly more dramatic anticancer activity.

Conclusion: An optimal formulation of BJOM superior to commercially available products and safe for medical application such as intravenous injection has been outlined along with its anticancer activity rating.     

Mathematical model for turbulent flow,heat transfer,and solidification

A steady‐state, two‐dimensional numerical model has been used to describe coupled liquid steel's turbulent flow and heat transfer with solidification for Fe‐C binary alloy in a crystallizer of inverse casting. The solid‐liquid phase change phenomena have been modeled by using continuum formulations and considering the mushy zone as porous media. The turbulence flow in the crystallizer has been accounted for using a modified version of the low‐Reynolds‐number κ?ε turbulence model. The flow pattern in the liquid zone and the temperature distribution in the solid, mushy, and liquid regions have been predicted. The numerical analysis indicates that the residence time of the mother sheet in the crystallizer is one of the key parameters. The effects of some other main parameters on the solidification behavior have also been studied, such as the thickness and the initial temperature of the mother sheet, and the superheat degree of liquid steel. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(7): 582–592, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10112     

Active fault tolerant control using multi-models based on RBF inverse system internal model

为了对一类非线性系统执行器时变故障进行有效诊断,研究了一种基于变增益扩张状态观测器的逆系统故障调节方法. 首先,通过一种时变增益的设计方法,来改进传统的恒增益扩张状态观测器,有效消除了在状态及故障估计初始阶段的“峰值”问题;其次,在依据故障估计值对原系统进行补偿调节的基础上,借助于逆系统的引入,对原非线性系统线性化,在使系统能对故障容错的同时,确保了系统无论故障发生与否的不变伪线性特性,进而又为其设计了鲁棒保性能控制,从而以不变的控制器使得系统始终具有了良好的性能及对逆建模误差的鲁棒性;最后,仿真算例对比验证了该方法的有效性.

     

分子对接方法在药物发现之外领域的应用

基于分子对接的反向虚拟筛选方法在药物靶点确定、老药新用以及药物副作用/毒理研究领域具有重要的应用前景,吸引了药物发现领域研究人员的广泛关注.首先对分子对接方法和蛋白质数据库进行细致的介绍,然后列举目前可以用于反向虚拟筛选的网络服务器,并列举该方法在药物设计领域的一些具体应用,最后对该方法目前所存在的问题进行讨论.

     

基于随机平均梯度下降和对比源反演的非线性逆散射算法研究

传统的迭代多尺度方法(iterative multiscaling approach, IMA)在求解非线性电磁场逆散射问题时,可以自适应提高成像空间的分辨率,缓解逆问题的病态性,但容易陷入局部极小值且无法做到实时重构。文中提出了一种迭代多尺度深度网络,该网络结合传统IMA和深度网络的优势,将IMA展开成深度网络模型（命名为IMA-Net）. 该方法迭代地执行一种感兴趣区域(regions of interest, ROI)提取算法,在不同尺度的ROI内构建目标函数,并将目标函数分解成若干个优化子问题,子问题的迭代更新过程映射到深度网络结构中,交替更新相关分量,求解出目标函数的最优值. 实验结果验证了该方法的有效性和优越性,为目标实时重构提供了一个有效方案.     

超塑性本构模型材料参数识别方法研究

金泉林等提出的超塑性本构关系考虑了三种微观变形机制和晶粒生长过程,但单纯依靠实验很难准确的测定该本构关系的材料参数.应用遗传算法和Levenberg-Marquardt算法,以Ti-6Al-4V为例,识别该超塑性本构关系中的材料参数.计算结果和实验结果符合的很好.最后讨论了各种微观变形机制的体积分数与应变、应变率和晶粒尺寸之间的关系,发现在大部分情况下扩散蠕变机制对超塑变形的贡献可以忽略.     

二维非稳态晶体生长的理论分析与拉普拉斯逆变换法

对定常速度下二维非稳态晶体生长的数学模型进行了分析,证明了解的唯一性,并运用Laplace逆变换法对该定解问题进行求解,最后给出了一个具体的例子.