棱边有限元法的边界树技术

介绍了棱边有限元法中选取边界树的原理和方法，提出了矩阵求秩法计算边界树，并结合实例说明其有效性。     

棱边有限元法在涡流场数值计算中的应用

本文讨论了三维瞬态涡流场的数值计算的两种方法：混合有限元－边界积分法（ＦＥＭ—ＢＩＭ）和新Ａ法．在ＦＥＭ—ＢＩＭ法中，以磁场强度Ｈ（用于涡流区）和样标量位（用于非涡流区）用为状态变量，充分利用了ＦＥＭ法和ＢＩＭ的各自优点，同时还采用了棱边单元的离散技术．这样，由于离散区域只限制于涡流区域及其边界，所以和常规有限元法相比，大大减少了未知量．在新Ａ法中，引入了补树的概念，使约束规范变得更为容量处理．本文最后给出了两个计算实例，并对这两种方法所得的结果进行了比较．     

基于免疫萤火虫算法的配电网低碳目标网架规划分析

当前在配电网网架规划中存在算法寻优能力差,二氧化碳削减量较低的问题,基于低碳化需求,将免疫萤火虫算法应用到配电网规划中,提出基于免疫萤火虫算法的配电网低碳目标网架规划分析方法。将低碳费用指标、电压安全指标和有功网损指标作为优化指标,在低碳目标的基础上构建配电网规划模型,采用免疫萤火虫算法,结合免疫克隆技术和萤火虫优化技术对配电网规划模型进行求解,实现配电网低碳目标的网架规划。实验结果显示,所提方法规划后的配电网二氧化碳削减量高,算法寻优能力强,符合低碳环保理念的同时能够获取最优规划方案,具有实用性。     

Structural reliability updating using experimental data

Journal of Mechanical Science and Technology - Conventional reliability analysis requires the information from an existing structure, such as a mechanical model and random distributed inputs. In...     

Guest-Stimulated Nonplanar Porphyrins in Flexible Metal−Organic Frameworks

Nonplanar porphyrins with out-of-plane distortions play crucial roles in many biological functions and chemical applications. The artificial construction of nonplanar porphyrins usually involves organic synthesis and modification, which is a highly comprehensive approach. However, incorporating porphyrins into guest-stimulated flexible systems allows to manipulate the porphyrin distortion through simple ad/desorption of guest molecules. Here, a series of porphyrinic zirconium metal−organic frameworks (MOFs) is reported that exhibit guest-stimulated breathing behavior. X-Ray diffraction analysis and skeleton deviation plots confirm that the material suffers from porphyrin distortion to form a ruffled geometry under the desorption of guest molecules. Further investigation reveals that not only the degree of nonplanarity can be precisely manipulated but also the partial distortion of porphyrin in a single crystal grain can be readily achieved. As Lewis acidic catalyst, the MOF with nonplanar Co-porphyrin exhibits active properties in catalyzing CO₂/propylene oxide coupling reactions. This porphyrin distortion system provides a powerful tool for manipulating nonplanar porphyrins in MOFs with individual distortion profiles for various advanced applications.     

Metal-Organic Frameworks for Gene Therapy and Detection

Gene therapy holds great promise as a biomedicine for treating cancer, viral infection, and recessive gene disorders, while genetic detection has been used for disease diagnosis and prevention. The appropriate carrier is crucial to improve the delivery efficiency of nucleic acids. Although viral and nonviral delivery vectors have been developed, their poor nucleic acid loading efficiency, off-target toxicity, and immunogenicity significantly hamper their use. Metal-organic frameworks (MOFs) have attracted a lot of attention owing to their high surface areas and tunable structures. Recently, nanometric MOFs are shown to be promising nonviral vectors in gene delivery and detection although at an early stage of development. This review focuses on highlighting the current status and promising breakthroughs of MOF use in nucleic acid delivery, including siRNA, miRNA and mRNA delivery, DNA gene delivery and transfection, as well as probes for detection of gene expression. This study will help promote the clinical transformation and application of gene modulation, gene delivery, and detection that use of MOFs can offer.