C3N4/ZnO复合材料可见光下的甲醛光电气敏性能

以水热法合成的ZnO纳米棒花为载体,将C_3N_4定量负载在其表面,制备C_3N_4/ZnO复合材料.由于C_3N_4与ZnO的能级匹配,可有效促进其光生电荷的分离,降低光生电荷复合率,显著提高载流子浓度,使其光电流明显增加.C_3N_4与ZnO质量比为2%的样品(2%C_3N_4/ZnO)性能最佳,其光电流在370 nm处可达120μA,为纯ZnO的2.4倍.在室温可见光下,2%C_3N_4/ZnO样品对HCHO的光电气敏响应值可达122%,比纯ZnO高4倍左右.结果表明,适量C_3N_4的负载有效延长了光生电荷的寿命,使ZnO材料在可见光区对HCHO气体表现出高效的光电气敏性能.     

基于动态阈值的混凝土裂缝高抗噪提取及识别方法

针对表面布有蜂窝麻面等复杂噪声的混凝土裂缝,提出了一种基于动态阈值的混凝土裂缝高抗噪提取方法.首先,通过灰度变换、高斯滤波、信息增强等技术弱化、去除噪声,增强图像中裂缝的亮度,提高裂缝与背景的对比度;然后,采用OTSU阈值分割算法去除伪裂缝,基于裂缝与干扰噪声面积的差异,引入动态阈值,实现各类型裂缝的提取;最后,基于边缘检测和裂缝骨架细化处理,计算裂缝的长度、宽度和面积3项特征参数.基于室内实验和室外实际桥梁拍摄的4组裂缝图像结果表明,4组裂缝的平均宽度分别为2.01、1.07、1.34、0.97 mm,说明该方法适用于不同背景下各类型裂缝的提取,具有较强的鲁棒性.     

Effect of Graphene Nanoplatelets addition on mechanical properties of pure aluminum using a semi-powder method

In recent years, graphene has attracted considerable research interest in all fields of science due to its unique properties. Its excellent mechanical properties lead it to be used in nano-composites for strength enhancement. This paper reports an Aluminum–Graphene Nanoplatelets(Al/GNPs)composite using a semi-powder method followed by hot extrusion. The effect of GNP nano-particle integration on tensile, compressive and hardness response of Al is investigated in this paper. It is demonstrated that 0.3 wt% Graphene Nanoplatelets distributed homogeneously in the matrix aluminum act as an effective reinforcing filler to prevent deformation. Compared to monolithic aluminum(in tension), Al–0.3 wt% GNPs composite exhibited higher 0.2% yield strength(+14.7%), ultimate tensile strength(+11.1%) and lower failure strain( -40.6%). Surprisingly, compared to monolithic Al(in compression), Al–0.3 wt% GNPs composite exhibited same 0.2% compressive yield strength and lower ultimate compression strength(- 7.8%),and lower failure strain(- 20.2%). The Al–0.3 wt% GNPs composite exhibited higher Vickers hardness compared to monolithic aluminum(+11.8%).Scanning electron microscopy(SEM), Energy-Dispersive X-ray Spectroscopy(EDS) and X-ray diffraction(XRD) were used to investigate the surface morphology, elemental percentage composition, and phase analysis, respectively.     

基于供应链业务流程改造的模块化设计

首先通过对A公司供应链业务流程现状进行分析,发现存在的问题,然后从模块化的角度对业务流程进行改造,并进一步对改造后的业务流程所涉及的4个模块进行了设计.所提出的供应链模块化设计,可将复杂流程简单化,使供应链管理更加明确、清晰,对于提高供应链的运作效率,缩短对需求响应时间具有重要作用.     

Optimal bundling and pricing decisions for complementary products in a two-layer supply chain

This article explores bundling and pricing decisions for two complementary products in a two-layer supply chain consisting of a multi-product manufacturer and a retailer. We establish four different pricing models under cases of decentralized decision, while considering different portfolio-bundling strategies of the manufacturer and the retailer. A game-theoretical method is used to characterize the corresponding equilibrium outcomes in each scenario. By further analyzing and comparing the maximum profits of all four possible scenarios, optimal bundling and pricing decisions for the manufacturer and the retailer are obtained, respectively. Model extensions and numerical examples are enriched to highlight the factors affecting optimal decision-making. Finally, valuable and interesting managerial insights are summarized. Results show that the upstream manufacturer always profits more when he sells complementary products separately. However, the optimal bundling decision of the downstream retailer is jointly determined by product complementarity (as a major factor) and the difference of product profitability (as a secondary factor). Market power cannot exert an influence on both optimal bundling decisions, but it can partly affect pricing decisions.     

对加强高校网络廉政舆情处置的思考

网络廉政舆情是把双刃剑,有利有弊,对网络廉政舆情及时搜集、科学研判、处置得当,将有利于推进高校的纪检监察工作。当前存在诸多高校负面网络廉政舆情,高校纪检监察部门在处置负面网络廉政舆情方面存在诸多误区,要有效处置负面网络廉政舆情,高校纪检监察部门应确立正确的原则,构建相应的机制。     

零散白货的货源组织问题和运输组织问题一体化

以铁路货运网络上的零散白货为研究对象,在充分考虑了货物的发到时间要求、货物的可运出时间与列车在沿途各站到发时间的协调约束、零散白货快运列车的多种停站方案和列车的非满轴运行特性等基础上,构建了以列车运营费用、货物的装卸作业费用、在货运站的库存费用和未满足最迟送达时间的惩罚费用之和最小为目标的混合整数规划模型.在小案例网络上对模型的求解效果进行验证并对一些重要参数进行了灵敏度分析,结果表明,本文提出的模型能优化基于时空网络的列车方案和每支OD可采用的运送方案.     

Semi-global stabilization via homogeneous output feedback for a class of nonlinear time-delay systems

The semi-global stabilization problem for a class of nonlinear systems with state time-delay is addressed in this paper. By using Lyapunov-Krasovskii functional method and homogeneous domination approach, a homogeneous observer and an output feedback controller with a scaling gain are designed. Then the scaling gain is adjusted such that the closed-loop system is semi-global asymptotically stable. A numerical example is presented to illustrate the effectiveness of the obtained results in this paper.     

馆藏图书资源借阅流通的统计分析

以武警指挥学院图书馆为例，对学员读者入馆和图书借阅情况进行了统计分析，揭示了读者的借阅需求和阅读倾向，提出了提高馆藏图书资源借阅流通率的合理化建议。     

探讨钢筋混凝土框架施工工艺

文章分析了钢筋混凝土框架结构施工中的工艺流程、质量控制工作，对工艺中存在的质量问题提出了相应的控制措施，以供工程技术人员参考。