环境变暖的危害及对策设想

近年来,全球气温快速增长,致使海平面上升,部分地区暴雨暴雪,部分地方干旱难耐,甚至大部分生物难以生存。因此,我们不能坐以待毙,而应积极采取措施遏制环境变暖,如植树造林,建立反射层,环保节能等。     

关于工程项目成本管理的体会

创造经济效益是建筑施工企业生存和发展的物质基础．是_T-作的最终落脚点;加强项目成本管理、获得较好经济效益是施工企业的最终目的：实施项目目标责任成本管理是搞好项目成本管理的有效方法。然而目标成本管理最为关键环节是项目成本的预测和控制。搞好成本预测,明确成本目标．并依据成本目标确定成本控制．实现成本控制目标．是成本管理的主要目标。     

变截面桥梁在变速移动荷载作用下的动力响应

为了模拟车辆/列车通过多跨变截面桥梁时的耦合动力响应,采用有限元法将移动车辆作为移动质量处理,使用Euler-Bernoulli变截面梁单元模拟桥梁结构,讨论了移动质量在梁桥模型上作匀变速运动下的有限元离散模式.在假定变截面模式的基础上,推导了梁高呈线性变化及抛物线性变化的矩形截面梁单元刚度矩阵和质量矩阵,并对多个变速移动荷载作用下的梁桥结构动力响应进行了数值模拟.运用该方法可以使变截面梁的分析简化,计算结果可作为工程设计和科学研究时的参考.     

Droplet-based microfluidic washing module for magnetic particle-based assays

In this paper, we propose a continuous flow droplet-based microfluidic platform for magnetic particle-based assays by employing in-droplet washing. The droplet-based washing was implemented by traversing functionalized magnetic particles across a laterally merged droplet from one side (containing sample and reagent) to the other (containing buffer) by an external magnetic field. Consequently, the magnetic particles were extracted to a parallel-synchronized train of washing buffer droplets, and unbound reagents were left in an original train of sample droplets. To realize the droplet-based washing function, the following four procedures were sequentially carried in a droplet-based microfluidic device: parallel synchronization of two trains of droplets by using a ladder-like channel network; lateral electrocoalescence by an electric field; magnetic particle manipulation by a magnetic field; and asymmetrical splitting of merged droplets. For the stable droplet synchronization and electrocoalescence, we optimized droplet generation conditions by varying the flow rate ratio (or droplet size). Image analysis was carried out to determine the fluorescent intensity of reagents before and after the washing step. As a result, the unbound reagents in sample droplets were significantly removed by more than a factor of 25 in the single washing step, while the magnetic particles were successfully extracted into washing buffer droplets. As a proof-of-principle, we demonstrate a magnetic particle-based immunoassay with streptavidin-coated magnetic particles and fluorescently labelled biotin in the proposed continuous flow droplet-based microfluidic platform.     

西方女性创业理论:过去的研究与未来的趋势

本文通过对国外女性创业相关文献的整理,简要回顾了国外女性创业研究的历史、女性创业研究的局限性和原因,并归纳总结了女性创业研究的发展趋势。在此基础上建立了女性创业研究的一般性框架,既弥补了以往研究的不足,又为后续的研究提供了一个清晰的思路。     

Atomic origin of spin-valve magnetoresistance at the SrRuO3 grain boundary

Defects exist ubiquitously in crystal materials, and usually exhibit a very different nature from the bulk matrix. Hence, their presence can have significant impacts on the properties of devices. Although it is well accepted that the properties of defects are determined by their unique atomic environments, the precise knowledge of such relationships is far from clear for most oxides because of the complexity of defects and difficulties in characterization. Here, we fabricate a 36.8° SrRuO₃ grain boundary of which the transport measurements show a spin-valve magnetoresistance. We identify its atomic arrangement, including oxygen, using scanning transmission electron microscopy and spectroscopy. Based on the as-obtained atomic structure, the density functional theory calculations suggest that the spin-valve magnetoresistance occurs because of dramatically reduced magnetic moments at the boundary. The ability to manipulate magnetic properties at the nanometer scale via defect control allows new strategies to design magnetic/electronic devices with low-dimensional magnetic order.     

A cost-effective wireless network migration planning method supporting high-security enabled railway data communication systems

As a typical railway Cyber-physical System (CPS), radio-based train control systems have been playing an increasingly important role in rail transit. The engaged network, Global System for Mobile Communications for Railway (GSM-R), which is an out-dated wireless communication technology, will be decommissioned due to diminishing support from industry, and a new generation successor, e.g. Long-Term Evolution (LTE), is urgently required to replace the current network. The radio-based train control systems must be safety critical, which relies on a high-security Data Communication System (DCS). In this paper, a novel wireless network migration methodology in DCS is proposed. By using this methodology, the high-security required DCS performance in radio-based train control systems is maintained and the network migration cost, e.g. the used number of base station (BS), is reduced when updating the GSM-R to LTE.     

基于模糊控制的高速列车运行控制系统研究

列车运行控制系统是保证列车安全、高速和高效运行的重要设备,根据列车在铁路线路上运行的客观条件和实际情况,对列车运行速度进行监督、控制和调整。高速、舒适是世界铁路发展的主要目标和方向,开发高效的高速列车运行控制系统势在必行。本文首先分析高速列车运行的控制问题,建立了高速列车运行的动力学模型,以给定的牵引和制动特性曲线得到参考速度曲线,将模糊控制技术应用于列车的运行控制中,实现了高速列车运行速度的智能控制。在Simulink中进行仿真研究,仿真结果表明,采用模糊控制的控制系统能确保列车实际运行速度很好地跟踪给定速度,系统的鲁棒性良好。     

Distributed cruise control of high-speed trains

In this work, the cruise control problem of high-speed trains’ movements is investigated. Both cases of a single high-speed train and multiple high-speed trains are under consideration. Different with most existing studies where the centralized control or the decentralized control methods are adopted based on a single point mass model of the train, in this paper, a distributed control mechanism is proposed by virtue of the graph theory, and the high-speed train’s model is built as a cascade of point masses connected by flexible couplers. For a single high-speed train, the neighboring cars interact through the coupling force with each other, which can be described by a connected topological graph by regarding each car as a node. Besides, the speed information communication among the cars is considered to be described by another directed topological graph. A distributed control strategy is then developed, with which all the cars of a train track a desired speed asymptotically and the neighboring cars keep a safety distance from each other. For the multiple high-speed trains running on a railway line, the in-train force interaction topology and the speed information communication topology of all the trains are more complex than those of a single train. A new cluster consensus technique is developed, by which a distributed control law is designed. Under the control law, the trains can track the desired speeds asymptotically, the headway distance between adjacent trains and the distance between the neighboring cars of a train can be kept in appropriate ranges. Finally, simulations are provided to illustrate the effectiveness of the obtained theoretical results.     

会展企业员工培训效果评估指标体系研究

针对会展企业面临的严重人才不足问题,运用培训效果评估的相关理论并结合会展企业的特性,依据柯式的四层次模型建立了会展企业员工培训效果评估的指标体系,以期为我国会展企业员工培训效果评估提供指导和借鉴。     

结合台州经济转型 探索发酵工程教改新模式

医药产业是台州经济的支柱产业。近年来,原料药的生产正逐渐从化学法向生物法转变,因此,台州经济也面临着转型升级。发酵工程是将多种知识应用到生产实践中的桥梁课程。本文介绍了台州学院结合台州地区的经济发展状况,与发酵工程课程建设的情况,探讨了学院在发酵工程教学过程中的改革措施,优化整合教学内容,加强实验教学和教学基地的建设,以提高教学质量,培养适合台州经济发展以及国家需要的综合型、创新型人才。     

Finite-time event-triggered consensus control for high-speed train with gradient resistance

Regarding the influence of the gradient resistance on multiple electric units, this paper investigates the finite-time event-triggered consensus control for a single high speed train. By considering the influence of the internal force of the train and the non-linear resistance, a multi-particle model of electric multiple units is established, in which the electric units are connected by elastic couplers. Based on the principle of event-triggered control, a consensus control strategy for electric multiple units is designed, which has disturbance rejection property and does not need continuous communication between electric units, hence effectively saving plenty of computing and communication resources. By using finite-time Lyapunov stability theorems to improve the event-triggered controller, it is found that finite-time consensus presents a fast convergence rate and good anti-interference performance. The stability of the control system is verified by Lyapunov function, where all electric units of high-speed train achieve finite-time consensus and exclude Zeno behavior. Finally, the effectiveness of the theoretical results is verified by two numerical simulations.     

Construction and operation of a microrobot based on magnetotactic bacteria in a microfluidic chip

Magnetotactic bacteria (MTB) are capable of swimming along magnetic field lines. This unique feature renders them suitable in the development of magnetic-guided, auto-propelled microrobots to serve in target molecule separation and detection, drug delivery, or target cell screening in a microfluidic chip. The biotechnology to couple these bacteria with functional loads to form microrobots is the critical point in its application. Although an immunoreaction approach to attach functional loads to intact MTB was suggested, details on its realization were hardly mentioned. In the current paper, MTB-microrobots were constructed by attaching 2 μm diameter microbeads to marine magnetotactic ovoid MO-1 cells through immunoreactions. These microrobots were controlled using a special control and tracking system. Experimental results prove that the attachment efficiency can be improved to ∼30% via an immunoreaction. The motility of the bacteria attached with different number of loads was also assessed. The results show that MTB can transport one load at a velocity of ∼21 μm/s and still move and survive for over 30 min. The control and tracking system is fully capable of directing and monitoring the movement of the MTB-microrobots. The rotating magnetic fields can stop the microrobots by trapping them as they swim within a circular field with a controllable size. The system has potential use in chemical analyses and medical diagnoses using biochips as well as in nano/microscale transport.     

实名制磁卡售检票虚拟系统分析设计

基于第二代身份证和网络的实名制磁卡售检票系统,将网上订票与自动售票结合起来,可以实现订票的网络化和取票的自动化,解决现实生活中买票难、买票累的实际问题,指出实名制磁卡售检票虚拟系统应具有车票信息管理、用户信息管理、磁卡信息管理等功能。     

基于ESP教学法的护理专业英语教学模式探讨

本研究为了了解护理专业学生采用ESP的教学现状,对41名学生进行问卷调查、随机访谈的方式调查。结果表明,学生们认为ESP教学目标明确,职业针对性强,ESP教学模式为英语教学改革提供了思路和方向。     

加强学生干部队伍建设 启动高校自我管理模式——浅谈高校学生会自治模式

高校学生干部是高校思政工作专职教师和学生的联系桥梁和沟通纽带,是高校学生思想政治工作队伍中一支强大的生力军,更是大学生实现自我教育、自我服务、自我管理的执行者和中坚力量。目前,高校中＂90后＂已成为当前高校学生干部的主体。结合社会背景、教育背景和家庭背景等因素,如何将＂90后＂培养成最优质的学生干部,并实现高校学生自我管理,是高校学生工作中非常值得探讨的一个问题。     

论知识产权侵权与反侵权的成本——收益博弈

由于信息不对称以及市场利益导向偏差的存在,知识产权侵权问题屡禁不止。通过成本-收益的博弈模型集中分析潜在侵权和反侵权行为的选择倾向,并从模型分析中得出若干结论,从而内在性地解释了知识产权侵权和反侵权的直接动因问题,同时也为加强知识产权保护提供了更明确的经济思路。     

上海轨道交通AC11型电动列车牵引和制动控制技术浅析

本文介绍了上海轨道交通AC11型电动列车控制过程,阐述了牵引和制动控制技术。并分析了列车控制故障的排除方法,从而提高维修技术,保障列车正线运营。     

关于桥梁施工技术的研究

桥梁质量的好坏直接关系到一个国家经济发展的快慢,影响桥梁质量的一个重要的因素就是桥梁裂缝的存在。因此,应采取合理的设计措施,采用先进的施工技术措施,最大限度的控制桥梁裂缝的出现。桥梁施工离不开相关施工技术的采用,只有这样,才能保证施工顺利进行,提高桥梁工程质量。然而,在施工过程中,由于受到多方面因素的影响,往往会出现裂缝。这些裂缝的出现对桥梁工程建设产生严重的不利影响,需要采取相应的措施进行处理。该文针对桥梁施工技术以及其裂缝产生的原因分别进行了分析和讨论。     

羽毛球后场正手高远球教学方法的实验研究

通过对比实验,对自主探究式教学法在羽毛球后场正手高远球教学中的运用与实践进行了研究。结果显示：“自主探究式教学法”与传统教学法相比,可以充分发挥教师的主导作用和学生的主体作用,培养学生的自主探究能力,促进学生正手击高远球的技术动作的掌握与提高．能有效提高高远球的质量,达到增强学习兴趣,提高课堂教学效果的目的,从而较快较好地完成教学目标。