Investigation of cracks in GaN films grown by combined hydride and metal organic vapor-phase epitaxial method

Dissipative particle dynamics (DPD), a mesoscopic simulation approach, is used to investigate the effect of volume fraction of polyethylene (PE) and poly(l-lactide) (PLLA) on the structural property of the immiscible PE/PLLA/carbon nanotube in a system. In this work, the interaction parameter in DPD simulation, related to the Flory-Huggins interaction parameter χ, is estimated by the calculation of mixing energy for each pair of components in molecular dynamics simulation. Volume fraction and mixing methods clearly affect the equilibrated structure. Even if the volume fraction is different, micro-structures are similar when the equilibrated structures are different. Unlike the blend system, where no relationship exists between the micro-structure and the equilibrated structure, in the di-block copolymer system, the micro-structure and equilibrated structure have specific relationships.     

尿素氮源掺杂二氧化钛对染料可见光脱色的研究

采用溶胶-凝胶法制备不同尿素氮源掺杂量的光催化剂尿素N/TiO2。尿素氮源掺杂后溶胶平均粒径仍在30-50nm之间,对溶胶粒径影响不大。尿素氮源掺杂可见光区域的吸收强度明显提高,但没有使吸收光波长产生明显的红移。红外谱图表明尿素与TiO2形成新的共价键以此参与钛酸四正丁酯的水解过程。0.01%和0.1%尿素掺杂可以提高催化剂可见光活性,继续增加掺杂量活性反而下降。染液初始浓度提高,催化剂脱色率则下降。0.01%尿素N/TiO2可见光下脱色4mg/L亚甲基蓝溶液,脱色率达92.8%。     

基于断裂理论的FRHPC破坏概率模型

为定量描述纤维增强高性能混凝土(FRHPC)的破坏过程及机理,运用断裂力学理论并引入孔隙分形维数,在测试了25组不同水胶比、不同养护制度试件的抗压强度、孔结构参数的基础上,建立了FRHPC的破坏概率模型.该模型不仅考虑了孔隙分形维数对基体裂缝复杂程度的影响,还考虑了纤维增强系数对基体失效概率的影响.模型回归分析结果表明:根据该模型计算的FRHPC破坏概率与破坏概率试验值有较高相关性,为定量表征FRHPC的破坏过程及机理分析提供了一种全新的视角和思路,也从侧面验证了模型的科学性与实用性.     

VVVF电梯及其速度监控

本文介绍了由可编程控制器控制的VVVF电梯控制系统的基本结构，并指出这种基本系统存在的问题，提出了改进方法。该方法经实践证明是可行的，对于提高此类电梯的运行可靠性、安全性有较大意义。     

一种基于异常流量的蠕虫入侵检测

该文对入侵检测常用检测方法做了简单概述,根据蠕虫与流量的关系,分析了基于异常流量检测蠕虫入侵的可行性,提出了一种基于异常流量的蠕虫检测模型,最后对将来需要进一步研究的工作提出了一些建议和设想。     

Tractable supply chain production planning,modeling nonlinear lead time and quality of service constraints

This paper addresses the task of coordinated planning of a supply chain (SC). Work in process (WIP) in each facility participating in the SC, finished goods inventory, and backlogged demand costs are minimized over the planning horizon. In addition to the usual modeling of linear material flow balance equations, variable lead time (LT) requirements, resulting from the increasing incremental WIP as a facility’s utilization increases, are also modeled. In recognition of the emerging significance of quality of service (QoS), that is, control of stockout probability to meet demand on time, maximum stockout probability constraints are also modeled explicitly. Lead time and QoS modeling require incorporation of nonlinear constraints in the production planning optimization process. The quantification of these nonlinear constraints must capture statistics of the stochastic behavior of production facilities revealed during a time scale far shorter than the customary weekly time scale of the planning process. The apparent computational complexity of planning production against variable LT and QoS constraints has long resulted in MRP-based scheduling practices that ignore the LT and QoS impact to the plan’s detriment. The computational complexity challenge was overcome by proposing and adopting a time-scale decomposition approach to production planning, where short-time-scale stochastic dynamics are modeled in multiple facility-specific subproblems that receive tentative targets from a deterministic master problem and return statistics to it. A converging and scalable iterative methodology is implemented, providing evidence that significantly lower cost production plans are achievable in a computationally tractable manner.     

弹载惯性仪表的可靠性强化试验

针对传统环境模拟试验周期长、费用高,且不能完全暴露惯性仪表设计和生产中的所有缺陷,将可靠性强化试验方法用于惯性仪表的可靠性试验。该方法区别于传统模拟环境试验的方法,它将在很短的时间内就可以使产品的缺陷暴露出来,极大地提高了试验效率。分析与试验表明:对惯性仪表进行可靠性强化试验之后,不仅会在设计初期就能对产品的的薄弱环节进行改进,而且还能完全暴露产品的潜在缺陷,最大限度地降低了试验成本,有效提高了弹载惯性仪表的可靠性。     

Inkjet printing effects of pigment inks on silk fabrics surface‐modified with O2 plasma

Without any preprocessing, silk fabric has lower ability to hold on water due to the smooth morphology of silk fibers. Therefore, patterns directly printed with pigment inks have poor color yields and easily bleed. Plasma surface‐treatment of silk fabric was carried out in an oxygen atmosphere under different experimental conditions. The samples were printed with magenta pigment ink after treatment. The results showed that the optimum treatment conditions we obtained were exposure time of 10 min at a working pressure of 50 Pa and a working power around 80 W. At such conditions, surface‐modified silk fabrics could obtain the effects of features with enhanced color yields and excellent pattern sharpness. Atomic force microscope images indicated that low‐temperature oxygen plasma initiated modifications to the surface of silk fiber with more grooves. Dynamic contact angle analysis showed that the hydrophilicity of silk fiber was remarkably improved after pretreatment with plasma. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

灵宝石英脉金矿石的浮选试验研究

灵宝石英脉金矿石进行了工艺矿物学研究,并根据研究结果,进行了单因素条件的浮选试验,制定了合理的浮选工艺流程,获得了金品位为32.30 g/t,回收率为92.25%的金精矿,其中含银品位为195 g/t、银回收率为71.12%。