价值分析方法在课程体系优化中的应用研究

以某地方综合性大学机械设计制造及其自动化专业的课程体系为例,应用价值工程原理,提出了课程模块价值系数的计算方法.采用问卷调查方式获取原始数据,定量分析了各课程模块的价值系数,并以此确定优化方向,提出课程体系优化的具体建议.     

Two‐Dimensional Crystallization of Rylene Diimide Based n‐Type Semiconductors Tuned by the Dimensions of the Aromatic Core at the Liquid–Solid Interface

The investigation of semiconductors at the surface provides opportunities to observe and understand the mechanism of molecular interaction for the design of semiconductors so that organic electronics with good performance can be built. Herein, the 2D crystallization of rylene diimide based n‐type semiconductors (i.e., 1–4 ) was explored at the liquid–highly oriented pyrolytic graphite interface by means of scanning tunneling microscopy. Rylene diimides 1 – 3 with increased aromatic dimensions show different surface crystallization behaviors and distinguished 2D patterns. The surface chirality was also found to be directly affected by the aromatic dimensions. The 2D patterns and the surface chirality could also be tuned by the nature of the solvent. In addition, molecular symmetry was found to be of great important for the formation of long‐range ordered 2D monolayers. This investigation highlights the importance of the rational design of molecular dimensions and geometrical symmetry in achieving determined 2D nanopatterns on surfaces, especially for the rylene diimide based n‐type semiconductors.     

Silk fibroin microfibers and chitosan modified poly (glycerol sebacate) composite scaffolds for skin tissue engineering

Porous mSF/PGS and CS/PGS composite scaffolds were prepared by the combination of poly(glycerol sebacate) (PGS) with silk fibroin microfibers (mSF) and chitosan (CS) as modifiers through particulate leaching and freeze-drying techniques. Both mSF/PGS and CS/PGS scaffolds show highly interconnected and open porous structures, and the crosslink density and water absorption of PGS were obviously enhanced by the modifiers. Moreover, the silk fibroin microfiber and chitosan can slow down and control the degradation rate of PGS. The biocompatibility of these porous PGS based composite scaffolds for skin tissue engineering was evaluated by cell culture experiments, and the results indicate of the good attachment, proliferation and deep penetration of cells into these composite scaffolds.     

基于自适应混沌控制的外汇干预有效性研究

中央银行外汇干预的有效性一直是金融领域研究和争论的热点问题,并且至今尚未达成一致的结论,寻找科学的理论与方法对其做进一步的探讨具有重要意义。针对该问题提出一种新的解决方案,即在扩展Dorn-busch汇率模型基础上,运用自适应混沌控制方法指导外汇干预策略,试图通过检验干预是否能够控制汇率时间序列的混沌行为并最终达到稳定汇率的目的,来论证外汇干预的有效性。仿真结果表明,通过自适应地寻找合理的干预尺度,外汇干预行为最终能够成功地将汇率稳定在系统均衡水平上。研究成果不但为外汇干预有效性给出了理论支持,还为中央银行外汇干预策略的制定提供了参考。     

典型气固污染下城市小区微环境的数值模拟

利用仿真软件Fluent并结合用户自定义函数对处于典型气固污染状况下的城市居民小区微环境进行了数值模拟.其中对气相雷诺平均方程采用realizableκ-ε模型予以封闭求解,对离散相采用拉格朗日随机轨道模型进行计算,对气态污染物的输运和扩散采用标量对流扩散守恒方程进行描述.结果显示,典型道路污染物扩散与道路走向和风向密...     

Tunable Phosphorescence/Fluorescence Dual Emissions of Organic Isoquinoline-Benzophenone Doped Systems by Alkoxy Engineering

Dual/multi-component organic doped systems with room-temperature phosphorescence (RTP) properties have been developed. However, the unknown luminescence mechanism still greatly limits the development of the doped materials. Herein, a new doped system exhibiting phosphorescence/fluorescence dual emission (Φ_phos=4–24 % and τ_phos=101–343 ms) is successfully constructed through prediction and design. A series of isoquinoline derivatives with different alkoxy chains were selected as the guests. Benzophenone was chosen as the host owing to the characteristics of low melting point and good crystallinity. The alkoxy chain lengths of the guests are first reported to be used to control the fluorescence and phosphorescence intensities of the doped materials, which results in different prompt emission colors. Additionally, the doped ratio of the guest and host can also control the luminous intensities of the materials. In particular, the doped materials still exhibit phosphorescent properties even if the ratio of the guest/host is as low as 1:100 000.     

工程项目工期预测的未确知模型

介绍了未确知有理数概念、运算、未确知期望,并提出了应用未确知有理数进行工程项目工期估算.由于工程项目管理涉及众多的工序,而各个工序的持续时间又是不确定的,因此,应用未确知有理数于工程项目网络图,可以得到的比传统的工程项目工期预测方法更满意、更合理的结果.     

SYNTHESIS AND X-RAY CRYSTAL STRUCTURE OF THE ASYMMETRIC DITHIADIAZENE BrC6F4NSNSC6H4NO2

The asymmetric dithiadiazene BrC₆F₄NSNSC₆H₄NO₂ crystallizes in the space group P-1 and exhibits a 1D polar chain structure linked via structure-directing Br···O₂N synthons.