改革实践教学模式、培养学生综合能力──增设给水排水专业质量检测实习的体会

对给排水专业在优化专业教学体系,深化专科教学模式及教学内容改革中,实施的四次大型综合性实践教学,进行了认真总结．经过改变随课跟进的实验教学旧模式,在教学计划中增设了“水质指标综合测试与水质评价”实习内容使分散的教学实验得以“水质监测与评价”为骨架,有机穿插在实践教学中,为专科学校培养复合应用型人才,进行了有益的探索与实践,并获得较好效果．     

The first measurement of an absolute surface concentration of reaction intermediates in ethylene hydrogenation

The first measurement of a turnover rate with respect to surface intermediate concentration in a high pressure heterogeneous catalytic reaction is reported. By using infrared-visible sum frequency generation to study the hydrogenation of ethylene on Pt(111), it was found that the surface concentration of -bonded ethylene, the key reaction intermediate, represented approximately 4% of a monolayer. Thus the absolute turnover rate per surface adsorbed ethylene molecule is 25 times faster than the rate measured per platinum atom. To explain these results, we propose a model of weakly adsorbed ethylene intermediates reacting on atop sites.     

Birefringent properties of diametrically loaded gradient-index lenses

Gradient-index (GRIN) lenses have been widely used as collimators in various fiber-optic sensors and as optical coupling devices in components designed for optical communication systems. However, relatively little attention has been paid to the birefringent properties of GRIN lenses and the potential for using them as photoelastic sensing elements in optical transducers. Analytical and experimental results are described that were obtained for the intensity distribution produced by studying a GRIN lens by using a polariscope. The residual birefringence inherent in an unloaded lens is initially studied. The lens is then assumed to be diametrically loaded and the superposition is studied by the method of ray tracing. When the results obtained from the simulation for a Selfoc, 0.25-pitch lens are compared with experimental data, an excellent agreement is obtained. Intensity increases monotonically with load, confirming that the lens would be a good choice for the sensing element of an optical transducer designed as part of a strain or acceleration measurement system. The numerical simulation is then used to study the influence of residual stress on sensitivity.     

Microfluidic continuous magnetophoretic protein separation using nanoparticle aggregates

We demonstrate a microfluidic continuous-flow protein separation process in which silica-coated superparamagnetic nanoparticles interact preferentially with hemoglobin in a mixture with bovine serum albumin, and the resulting hemoglobin-nanoparticle aggregates are recovered online using magnetophoresis. We present detailed modeling and analysis of this process yielding quantitative estimates of the recovery of both proteins, validated by experiments. While several previous studies utilize an average particle size in modeling magnetophoretic particle trajectories or process design, in this study we emphasize the importance of accounting for particle size distributions in calculating particle recovery, and therefore in estimating separation efficiency. We combine experimentally measured size distributions of protein-nanoparticle aggregates with simulations of particle trajectories and provide a simple analytical method to calculate the efficiency of separation at various flow speeds, which fully accounts for heterogeneity in particle sizes. Our method can potentially be used for affinity based biomolecular separations at both analytical and preparative scales by exploiting well-established techniques to functionalize nanoparticle surfaces with selective ligands. Further, the modeling methodology presented here may be applied to provide better estimates of particle recovery in a broad range of magnetophoretic separation processes involving heterogeneity in particle sizes.     

Integratable non-clogging microconcentrator based on counter-flow principle for continuous enrichment of CaSki cells sample

This study addresses the need to reduce the risk of clogging when preparing samples for cell concentration, i.e., the CaSki Cell-lines (epidermoid cervical carcinoma cells). Aiming to develop a non-clogging microconcentrator, we proposed a new counter-flow concentration unit characterized by the directions of penetrating flows being at an obtuse angle to the main flow, due to employment of streamlined turbine blade-like micropillars. Based on the optimization results of the counter-flow unit profile, a fractal arrangement for the counter-flow concentration unit was developed. A counter-flow microconcentrator chip was then designed and fabricated, with both the processing layer and collecting layer arranged in terms of the honeycomb structure. Visualized experiments using CaSki cell samples on the microconcentrator chip demonstrated that no cell-clogging phenomena occurred during the test and that no cells were found in the final filtrate. The test results show an excellent concentration performance for the microconcentrator chip, while a concentrating ratio of >4 with the flow rate being below 1.0 ml/min. As only geometrical structure is employed in the passive device, the counter-flow microconcentrator can be easily integrated into advanced microfluidic systems. Owing to the merit of non-clogging and continuous processing ability, the counter-flow microconcentrator is not only suitable for the sample preparation within biomedical field, but also applicable in water-particle separation.     

A study to support agile methods more effectively through traceability

Traceability is recognized to be important for supporting agile development processes. However, after analyzing many of the existing traceability approaches it can be concluded that they strongly depend on traditional development process characteristics. Within this paper it is justified that this is a drawback to support adequately agile processes. As it is discussed, some concepts do not have the same semantics for traditional and agile methodologies. This paper proposes three features that traceability models should support to be less dependent on a specific development process: (1) user-definable traceability links, (2) roles, and (3) linkage rules. To present how these features can be applied, an emerging traceability metamodel (TmM) will be used within this paper. TmM supports the definition of traceability methodologies adapted to the needs of each project. As it is shown, after introducing these three features into traceability models, two main advantages are obtained: 1) the support they can provide to agile process stakeholders is significantly more extensive, and 2) it will be possible to achieve a higher degree of automation. In this sense it will be feasible to have a methodical trace acquisition and maintenance process adapted to agile processes.     

一种陆地车辆对抗演示系统设计

设计一种陆地车辆对抗演示系统,该系统主要包括图像采集单元、上位机控制处理平台单元、无线传输单元、驱动控制单元、对抗判决系统单元和敌我识别系统单元;设计中采用4辆车辆(2对2模式)进行对抗实验,实验表明设计的陆地车辆对抗演示系统可以实现对前方环境和对方对阵情况的实时图像获取和处理、显示、无线收发控制、计算、轨迹控制、特征识别、定位、文件管理、数据传输、生命值显示以及声音报警等功能;实验对抗结果:乙方两辆车4个生命值显示灯全部熄灭,甲方对抗胜利.     

网络状态感知的标识映射系统研究

可扩展性是当今路由系统面临的最主要的问题之一;学术界一致认为位置与标识分离的思想是解决路由可扩展性问题的最有效的方法;然而,在位置与标识分离的网络中,如何设计一个高效的映射服务系统仍是一个难题;文中提出了影响映射服务系统性能的三个主要因素,并基于对这三个主要因素的分析,提出了一个网络状态感知的标识映射系统NAMS; NAMS包含两个关键元素:网络感知Agent和服务节点;我们认为,NAMS是解决高效映射服务系统设计实现问题的有效途径.     

高性能机群计算本科教学研究

针对目前高性能机群人才需求旺盛而高校对高性能机群计算知识普及不够的现状,以培养工程实践性机群系统管理人员为目标,阐述面向高校计算机专业本科生开设高性能机群计算课程的教学目标;并进行课程设计,包括教学内容及教材选取、课时安排以及教学方法设计。北京工业大学的教学实践表明,上述课程设计取得了较好的教学成效。     

基于物联网的物流车辆监控系统的设计与实现

论文基于物联网的基本概念和体系结构,对物流车辆监控系统的原理、系统硬件总体框架、系统软件总体框架结构的设计和系统实现的关键技术进行了介绍,该系统能实现GPS定位跟踪、运输路线指挥、累计重量报表输出、历史数据查询和实时情况追踪等功能,能有效地解决运输任务的监控和管理,从而大大提高了运输任务管理的效率。