基于下游大水位变率的下水式垂直升船机随动技术的设计与实现

下游航道水位变率大,快速适应水位变化的准确停位随动技术,对下水式升船机的传动控制很重要.本文介绍下水式垂直升船机随动控制技术.首先,对控制对象的特性进行分析,描述了系统的速度运行曲线,对位置控制功能进行了研究.然后,搭建试验平台对本控制方案的性能进行了测试,给出了测试的方法和试验结果.实验结果表明本控制系统具有定位精度高、响应速度快等优点,能够适应下游大水位变化率的下水式垂直升船机准确停位要求.     

新冠肺炎疫情对民航的影响分析与政策建议

为给政府制定应对策略提供决策支持，基于航班运行数据分析了新型冠状病毒肺炎疫情对民航造成的影响。通过分析2003年“非典”和新型冠状病毒肺炎疫情对民航影响的差异，基于情景假设对2020年民航运输发展形势进行了预测分析，并提出有关政策建议。研究结果表明：新型冠状病毒肺炎疫情对民航市场需求造成了严重的冲击，2020年民航运输形势不容乐观，预计年旅客运输量同比基本持平或下降10.9%。政府部门需在做好疫情防控期间运输保障工作的同时，加快出台积极的产业政策以支撑民航发展。     

中国近周边海域船舶排放清单及排放特征研究

为分析我国沿海船舶大气污染物排放特征,本研究以船舶自动识别系统数据为基础,收集整理国内外船舶静态数据、排放参数,结合船舶实际航行资料,采用动力法估算了中国近周边海域2014年的船舶排放清单,并分析了靠港、锚泊、港内机动、低速、巡航5个船舶状态下的排放特征,按不同海区对排放进行了统计,并给出了我国三个排放控制区的船舶大气污染物排放情况。结果表明,中国近周边海域范围内由于船舶活动一年产生的硫氧化物、氮氧化物、PM10分别约为87.98万吨、137.84万吨、11.73万吨。排放源分析表明,在船舶的主机、辅机和锅炉3种排放源中,主机是主要排放源,且在航行状态上低速巡航状态排放最大。船舶排放污染物的空间分析表明,90%的船舶排放发生在海岸线至领海基线外96海里范围内,即距离陆地200公里的海域内。     

Ridership drivers of bus rapid transit systems

We have collected information on 46 bus rapid transit (BRT) systems throughout the world to investigate the potential patronage drivers. From a large number of candidate explanatory variables (quantitative and qualitative), 11 sources of systematic variation are identified which have a statistically significant impact on daily passenger-trip numbers. These sources are fare, headway, the length of the BRT network, the number of corridors, average distance between stations; whether there is: an integrated network of routes and corridors, modal integration at BRT stations, pre-board fare collection and fare verification, quality control oversight from an independent agency, at-level boarding and alighting, as well as the location of BRT. The findings of this paper offer important insights into features of BRT systems that are positive contributors to growing patronage and hence should be taken into account in designing and planning BRT systems.     

A two-phase model for dry port location with an application to the port of Dalian in China

This paper provides guidance for an optimal and reasonable dry port layout for the port of Dalian in China. We present a two-phase framework on the location of dry ports, which solves the selection of candidate inland cities and optimal dry port location choice, respectively. Fuzzy C-Means Clustering is applied to select alternative cities in the vast hinterland of the seaport of Dalian, with a view to identify evaluation factors that affect the location selection decision. A cost-minimisation linear programming solution is proposed, with the aid of a genetic algorithm, to choose the optimal location as well as capacity level among the candidate inland cities.     

A proposed vision and vehicle-to-infrastructure communication-based vehicle positioning approach

It is essential to obtain accurate location of vehicles for new applications of Intelligent Transportation Systems. To remedy the defects of present Global Positioning System and vehicle-to-infrastructure (V-I) positioning technology, a new positioning approach based on vision and V-I communication is proposed. This approach aims at lane-level positioning with lower cost than conventional ones. In this approach, the position of the vehicle is represented by its lateral position (the lane number) and longitudinal position (the distance from entrance of the road) in a course coordinate system along the road; the specific lane the vehicle is occupying (the lane number) can be judged using the information of lane lines detected by vision systems; then the distance to the vehicle is obtained by a Road Side Unit (RSU) during the V-I communication; and the longitudinal position is calculated. The error of the approach on typical operating conditions is analyzed, indicating that the new approach can achieve the accuracy of less than 0.31 m for straight road and 0.58 m for typical arc road with ultra-wideband communication and ranging technologies and rational arrangement of RSUs. The feasibility of this approach is presented.     

Approximate optimal AUTOSAR software components deploying approach for automotive E/E system

The AUTOSAR has been developed as the worldwide standard for automotive E/E software systems, making the electronic components of different suppliers to be employed universally. However, as the number of component-based applications in modern automotive embedded systems grows rapidly and the hardware topology becomes increasingly complex, deploying such large number of components in automotive distributed system in manual way is over-dependent on experience of engineers which in turn is time consuming. Furthermore, the resource limitation and scheduling analysis make the problems more complex for developers to find out an approximate optimal deploying approach in system integration. In this paper, we propose a novel method to deploy the AUTOSAR components onto ECUs with the following features. First, a clustering algorithm is designed for deploying components automatically within relatively low time complexity. Second, a fitness function is designed to balance the ECUs load. The goal of our approach is to minimize the communication cost over all the runnable entities while meeting all corresponding timing constraints and balancing all the ECUs load. The experiment results show that our approach is efficient and has well performance by comparing with other existing methods in specific and synthetic data set.     

京津客运专线悬浇连续梁桥面平整度控制技术

结合京津客运专线悬臂浇筑连续梁的施工过程,介绍了主梁的整体线形及各节段间的接缝控制和桥面横向六面排水坡等平整度控制内容,对全桥合拢后桥面的平整度缺陷处理方法进行了阐述,对今后悬浇连续梁施工中的桥面平整度控制与处理有一定的借鉴作用。     

Apoptin原核表达载体的构建及在大肠杆菌中的表达

目的构建Apoptin的原核表达载体,并制备抗原物质Apoptin融合蛋白。方法在获得Apoptin融合基因的基础上,成功构建了Apoptin的高效原核表达载体pET-28a( )-Apoptin,将该质粒转化至大肠杆菌E.coliBL21(DE3)受体菌中,以IPTG对其进行诱导表达,聚丙烯酰胺凝胶电泳分析目的蛋白。结果转化有Apoptin的原核表达载体pET-28a( )-Apoptin的大肠杆菌E.coliBL21(DE3)经IPTG诱导后,经SDS-PAGE分析,在相对分子质量约17 000的位置出现目的蛋白条带,大小与Apoptin融合蛋白一致。结论Apoptin原核表达载体pET-28a( )-Apoptin能够表达出Apoptin融合蛋白,为进一步的Apoptin研究和制备Apoptin抗体奠定了基础。     

幽门螺杆菌尿素通道蛋白基因UreI载体的构建、融合表达及纯化

目的构建幽门螺杆菌(H.pylori,Hp)尿素通道蛋白基因UreI的融合表达载体,并在E.coliBL21中表达,为进一步研究UreI的功能奠定基础。方法利用分子克隆技术以Hp DNA染色体为模板,扩增Hp UreI基因片段,将目的基因UreI与载体pET32a( )分别经kpnⅠ和HindⅢ双酶切,纯化,连接。筛选阳性重组载体,转化大肠杆菌BL21,以IPTG诱导表达pET32a( )/UreI融合蛋白。表达产物经Ni-NTA琼脂糖树脂纯化后,用SDS-PAGE及Western blot分析。结果经酶切、测序分析表明,插入的基因片段为Hp UreI编码基因,由585 bp组成,与GenBank相应菌株HP AM417 609序列完全一致,无碱基突变。经SDS-PAGE分析显示重组质粒pET32a( )/UreI在原核细胞中得到了高效融合表达,其重组融合蛋白分子量为130 ku,经Ni-NTA琼脂糖树脂纯化后,其纯度达95%以上,Western blot分析显示,该重组融合蛋白可被6-His鼠抗单克隆抗体所识别,具有良好的反应原性。结论成功地克隆和构建了原核表达载体pET32a( )/UreI,并在原核细胞中得到了高效融合表达。