Pyridine-induced interfacial structural transformation of tetraphenylethylene derivatives investigated by scanning tunneling microscopy

The two-dimensional self-assembly behaviors of tetraphenylethylene (TPE) molecules are significant for further applications, but reports are rare. The self-assembled structures of two C₂-symmetry TPE derivatives (H₄TCPE and H₄ETTC) possessing propeller structures and their stimulus responses to the addition of vinylpyridine derivatives were thoroughly studied with the assistance of scanning tunneling microscopy (STM) technique in combination with density functional theory (DFT) calculations. Although their chemical structures were similar, the H₄TCPE and H₄ETTC molecules self-assembled into closely packed lamellar and quadrilateral structures, respectively, at the 1-heptanoic acid/HOPG interface. After the addition of pyridine derivatives (DPE, PEBP-C4, and PEBP-C8), H₄TCPE and H₄ETTC showed different responsiveness resulting in different co-assembly structures. The results indicated that the structures of pyridine derivatives—including backbones and substituents—affected the intermolecular interactions of both H₄TCPE/pyridine and H₄ETTC/pyridine systems. The modification of the self-assembly behaviors of propeller-shaped H₄TCPE and H₄ETTC would contribute to the construction of more complex multilevel nanostructures.

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Regulation of Polymer Configurations Enables Green Solvent-Processed Large-Area Binary All-Polymer Solar Cells With Breakthrough Performance and High Efficiency Stretchability Factor

With the great potential of the all-polymer solar cells for large-area wearable devices, both large-area device efficiency and mechanical flexibility are very critical but attract limited attention. In this work, from the perspective of the polymer configurations, two types of terpolymer acceptors PYTX-A and PYTX-B (X = Cl or H) are developed. The configuration difference caused by the replacement of non-conjugated units results in distinct photovoltaic performance and mechanical flexibility. Benefiting from a good match between the intrinsically slow film-forming of the active materials and the technically slow film-forming of the blade-coating process, the toluene-processed large-area (1.21 cm²) binary device achieves a record efficiency of 14.70%. More importantly, a new parameter of efficiency stretchability factor (ESF) is proposed for the first time to comprehensively evaluate the overall device performance. PM6:PYTCl-A and PM6:PYTCl-B yield significantly higher ESF than PM6:PY-IT. Further blending with non-conjugated polymer donor PM6-A, the best ESF of 3.12% is achieved for PM6-A:PYTCl-A, which is among the highest comprehensive performances.     

统一门户工作下门户网站安全防护研究

门户网站是对外信息发布和网上业务办理的窗口,是与外界进行网络沟通的桥梁,它的正常工作与否不仅直接关系到我们提供的服务质量,而且关系到广西移动的公众形象和客户资料的安全与否.为了提高“统一门户”整合工作后门户网站的安全性,在实现集团“统一门户”工作要求的同时,保证门户网站的安全性,需要提高门户网站安全防控能力.     

项目导向的计算机审计教学方法的创新与探索

针对目前计算机审计课程教学过程中存在课堂教学与计算机审计实践脱节问题,笔者根据自身教学经验,并结合参与国家审计署项目审计的经历,提出以项目为导向、整体模块化、模块多样化的计算机审计教学方法,实现教学理论与审计实践的较好结合,充分调动教学中两个主体的主观能动性,提高了教学质量。     

面向大规模数据集的近邻传播聚类

近邻传播聚类在计算过程中需构建相似度矩阵,该矩阵的规模随样本数急剧增长,限制了算法在大规模数据集上的直接应用。为此,提出一种改进的近邻传播聚类算法,利用数据点的局部分布,借鉴半监督聚类的思想构造稀疏化的相似度矩阵,并对聚类结果中的簇代表点再次或多次聚类,直至得到合适的簇划分。实验结果表明,该算法在处理能力和运算速度上优于原算法。     

基于SSL的软件序列号网上验证分析与实现

在软件序列号网上验证过程中,若数据为明文传输的话,则容易被捕获及分析,从而令验证失效。为降低软件盗版比例,介绍序列号验证技术的基本原理,通过实例详细说明利用SSL加密验证过程的必要性,给出获取SSL服务器证书的不同途径,利用Windows HTTP服务（WinHTTP）为软件开发人员提供解决方案。提出的方法有效、实用且易于实现。     

An integrated approach for rating engineering characteristics’ final importance in product-service system development

Product-service system (PSS) approach has emerged as a competitive strategy to impel manufacturers to offer a set of product and services as a whole. A three-domain PSS conceptual design framework based on quality function deployment (QFD) is proposed in this research. QFD is a widely used design tool considering customer requirements (CRs). Since both product and services influence satisfaction of customer, they should be designed simultaneously. Identification of the critical parameters in these domains plays an important role. Engineering characteristics (ECs) in the functional domain include product-related ECs (P-ECs) and service-related ECs (S-ECs). ECs are identified by translating customer requirements (CRs) in the customer domain. Rating ECs’ importance has a great impact on achieving an optimal PSS planning. The rating problem should consider not only the requirements of customer, but also the requirements of manufacturer. From the requirements of customer, the analytic network process (ANP) approach is integrated in QFD to determine the initial importance weights of ECs considering the complex dependency relationships between and within CRs, P-ECs and S-ECs. In order to deal with the vagueness, uncertainty and diversity in decision-making, the fuzzy set theory and group decision-making technique are used in the super-matrix approach of ANP. From the requirements of manufacturer, the data envelopment analysis (DEA) approach is applied to adjust the initial weights of ECs taking into account business competition and implementation difficulty. A case study is carried out to demonstrate the effectiveness of the developed integrated approach for prioritizing ECs in PSS conceptual design.     

A conjugate bayesian approach for calculating process capability indices

Process capability indices measure the ability of a production process to produce items within specification limits. The calculation of process capability indices has been focusing on using traditional frequency approach, which requires a large sample size for an accurate estimation. In order to eliminate this defect of traditional frequency approach on multi-batch and low volume production, Bayesian approach was used. The conjugate Bayesian approach is chosen to estimate the process distribution parameters. The algorithm with these conjugate Bayes estimators is proposed for measuring the process capability for multi-batch and low volume production. A case study is presented to demonstrate how the approach can be applied to actual data collected in practice.     

Numerical solutions of Duffing equations involving both integral and non-integral forcing terms

In this paper, an improved variational iteration method is presented for solving Duffing equations involving both integral and non-integral forcing terms. The main advantage of this modification over the standard variational iteration method (VIM) is that it can avoid unnecessary repeated computation in determining the unknown parameters in the initial solution. Numerical results reveal that the improved method is simple and efficient.