A multi-objective optimal approach to automated construction of sacrificial multi-piece molds

Sacrificial multi-piece molds can be used for producing complex parts. To obtain the optimal design of molds automatically, a multi-objective optimal approach is proposed. Mold pieces number, material utilization and partitioning area are taken as the objective functions, and the machinability of each mold piece is taken as constraint condition. Genetic algorithm (GA) is adopted to realize global optimization of partitioning process. Each mold piece in optimal scheme can be manufactured by milling and drilling operations, which reduce the tooling cost and shorten product cycle obviously. Using the proposed approach, mold design can be significantly automated for making complex parts.     

Multi-try counter-meshing gears discrimination device based on MEMS technology

A multi-try counter-meshing gears (CMG) discrimination device based on micro electromechani-cal system (MEMS) technology was designed for some specified information fields. The discrimination deviceconsists of two groups of metal CMG, two pawl/ratchet mechanisms, two driving micromotors and two re-setting micromotors, which make the CMG withdraw by raising the pawls. The energy-coupling element isa photoelectric sensor with a circular plate which is notched. Micromotor is fabricated using the ultravioletLiGA (UV-LiGA) fabrication process and precision mechanical engineering. The discrimination device has thefunction which can automatically reset, with the correct resetting code, it can be tried another times.     

上海市公交移动电视信息发布情况调查研究

公交移动电视是一种全新的大众媒体,课题对上海市公交移动电视的信息发布情况进行了初步的调查研究.这次调查研究包括两部分,乘客满意度调查和公交信息需求调查,分别在上海市市区公交线路和市郊公交线路进行.调查结果显示,绝大部分乘客在乘车时愿意收看公交移动电视.目前移动电视最需要改进的环节在节目种类的选择上,而每个节目持续的时间应在20 min之内为宜.乘客在乘车途中对交通出行方面的信息有着特定的需求,应充分发挥移动电视作为信息发布平台的优势,向乘客发布及时、准确的交通出行信息,如公交车行走路线的道路状况、公交车到站预测时间等.另外,通过对市区和郊区的调查结果进行比较发现,市区乘客和郊区乘客对公交移动电视发布信息的需求差异不大.     

城市轨道交通停车换乘设施规划研究

本文在借鉴国外轨道交通停车换乘方面经验并结合国内相关研究的基础上,首先探讨了换乘设施的规划目标和原则,然后从三个方面重点分析了停车换乘设施建设的影响因素并提出了解决问题的方法,以供交通决策者和相关人员参考。     

AQP4在COPD支气管黏膜的表达及其与患者肺功能、气道黏膜炎症的相关性

目的通过免疫组化法检测支气管黏膜中水通道蛋白-4(aquaporin-4,AQP4)的表达,观察正常组和慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)组支气管黏膜中AQP4表达与气道黏膜炎症及肺功能的关系,明确AQP4在COPD发生、发展中的作用,为COPD的防治开辟新途径。方法选择正常人和COPD患者各30例,测试肺功能,并行支气管镜检查,取得支气管黏膜标本,用免疫组化法检测AQP4表达,HE染色观察支气管黏膜炎症细胞浸润程度。结果COPD组较对照组AQP4表达减弱有极显著差异(P<0.001)。AQP4表达和FEV1/FVC、FEV1/pred%呈正相关(P<0.001),与支气管黏膜炎症严重程度呈负相关(P<0.001)。结论COPD患者AQP4表达减少可能是其肺功能下降及气道炎症加重的原因之一。临床上可以通过改善AQP4治疗COPD。     

综合重症监护病房患者呼吸机相关性肺炎的病原学和耐药性分析

目的探讨病原菌在综合重症监护病房(ICU)患者呼吸机相关性肺炎(VAP)中的分布及对常用抗生素的耐药情况。方法对我院2004-2006年综合ICU患者VAP病原菌的分布及耐药性进行回顾性统计分析。结果从302例综合ICU VAP患者下呼吸道深部分泌物标本中分离出347株病原菌,主要病原菌是铜绿假单胞菌(32.3%)、鲍曼不动杆菌(31.1%)、金黄色葡萄球菌(16.7%)、克雷伯菌(7.5%)与凝固酶阴性葡萄球菌(6.1%)。革兰阴性杆菌(G-杆菌)对哌拉西林、头孢噻肟耐药率最高,对碳青霉烯类及加酶抑制剂抗生素耐药率最低;革兰阳性球菌(G 球菌)对青霉素类、克林霉素及红霉素耐药率高,对万古霉素、喹诺酮类抗生素耐药率低。结论G-杆菌是综合ICU患者VAP最主要的病原菌,多重耐药性高;耐甲氧西林金黄色葡萄球菌(MRSA)和耐甲氧西林凝固酶阴性葡萄球菌(MR-SCNS)的分离率高且耐药严重。临床医师应根据病原菌学及抗菌药物敏感性资料,及时选择合理的抗生素控制感染,延缓耐药菌株的产生。     

浅谈钻孔灌注桩施工中的常见问题及处理方法

本文着重结合工程实际提出了桥梁钻孔灌注桩施工过程当中坍孔、钻孔倾斜度过大和断桩的发生原因及处治措施,对类似工程将有一定的借鉴作用。     

软件技术专业校企合作办学模式的探索与实践

高职院校办学必须立足于培养动手能力强,能迅速适应劳动岗位的高技能型IT人才。本文结合校企合作办学模式的背景和发展现状,从实训中心建设,师资队伍建设和教学内容改革等三个方面阐述软件技术专业校企合作办学模式的新思路。     

拐角铺互通立交方案比选

拐角铺互通是京石高速与石家庄高速外环的北环(张石支线)交叉,连接东环的重要枢纽互通.该互通用以连接张石高速、京石高速以及规划的石家庄高速外环,对改善石家庄市北出口的交通环境,缓解市内交通压力有重要意义.比较详细的介绍了该互通的方案设计.     

Driver behavior formulation in intersection dilemma zones with phone use distraction via a logit-Bayesian network hybrid approach

Use of cellular phone while driving is one of the top contributing factors that induce traffic crashes, resulting in significant loss of life and property. A dilemma zone is a circumstance near signalized intersections where drivers hesitate when making decisions related to their driving behaviors. Therefore, the dilemma zone has been identified as an area with high crash potential. This article utilizes a logit-based Bayesian network (BN) hybrid approach to investigate drivers' decision patterns in a dilemma zone with phone use, based on experimental data from driving simulations from the National Advanced Driving Simulator (NADS). Using a logit regression model, five variables were found to be significant in predicting drivers' decisions in a dilemma zone with distractive phone tasks: older drivers (50–60 years old), yellow signal length, time to stop line, handheld phone tasks, and driver gender. The identified significant variables were then used to train a BN model to predict drivers' decisions at a dilemma zone and examine probabilistic impacts of these variables on drivers' decisions. The analysis results indicate that the trained BN model was effective in driver decision prediction and variable influence extraction. It was found that older drivers, a short yellow signal, a short time to stop line, nonhandheld phone tasks, and female drivers are factors that tend to result in drivers proceeding through intersections in a dilemma zone with phone use distraction. These research findings provide insight in understanding driver behavior patterns in a dilemma zone with distractive phone tasks.