论浅水多波束测量质量保证措施

在对影响多波束测量精度、质量的关键因素进行分析的基础上,提出了保证测量质量的措施。     

浅谈3S技术在公路勘察设计中的应用

对3S技术及其发展状况进行了阐述,着重讨论了3S技术在公路勘察设计中的应用,为3S技术在交通领域的进一步推广应用提供参考。     

区域公路OD调查关键问题探讨

交通调查数据的采集与处理是交通预测的基础,在区域范围内开展公路0D调查工作,能为政府决策和公路规划、设计、科研与养护管理等方面提供重要的资料和数据。目前我国已有一些省份已开展了这方面的工作,因此有必要结合国内外一些省市的调查实例,探讨交通小区划分、调查点的布置、抽样率的确定以及调查方法与数据合成技术的选择等五个方面的问题,以期为今后调查工作的开展提供帮助。     

浅谈道路工程设计时所应具备的计算机能力

针对工程勘察设计中对于道路工程设计人员的计算机应用能力的要求,对勘察设计人员掌握相应的计算机辅助设计技术以提高设计质量和工作效率问题进行阐述,可为设计人员提高计算机综合应用能力提供参考。     

GPS技术在道路观测中的应用

介绍了道路断面测量的基本要求,比较了GPS技术和全站仪测量方法的利弊,详细介绍了GPS测量的转换参数解算和动态GPS测量的误差。介绍了一个GPS测量的实例。是后提出了应用GPS技术应注意的事项。     

长距离顶管平面控制测量关键技术

为解决现有顶管平面测量方法对于顶管机在长距离掘进中的不适用问题,以与顶管机掘进距离成正比的精度需求为切入点,按照不同距离精度需求寻找适当的平面控制测量方法,并把各类顶管平面控制测量技术与单站轨迹式定向长距离顶管导向系统有机结合,在满足精度需求的同时提高工作效率、降低工作强度.采用该方法实现了苏州城区第二水源——阳澄湖引...     

Driver models in automobile dynamics application

Understanding the driver of an automobile has been attractive to researchers from many different disciplines for more than half a century. On the basis of their acquirements, models of the (human) driver have been developed to better understand, analyse and improve the combined couple of driver and automobile. Due to distinctive demands on the models in accordance with different kinds of applications, a variety of driver models is available. An overview of driver models is given with respect to their application and different methodical modelling approaches. The emphasis is put on the interest of engineers, who generally focus on the automobile (like design and optimization of vehicle components and the overall vehicle dynamics behaviour) by applying their approved (mathematical) methods. Nonetheless, a brief look beyond is added to better complete the view on the involved task of driving and driver modelling for automobile dynamics application.     

Asymmetric regular sampling SPWM method based on tangent-secant midpoint approximation applied to intermediate frequency inverter power supply北大核心CSCD

［Objective］In order to reduce the switching frequency of an intermediate frequency inverter power supply, ensure the quality of the output waveform and realize digitalization easily, a SPWM sampling method based on a tangent-secant midpoint approximation is proposed. ［Methods］It is proven by deduction that the quantitative relationship of the natural sampling method can be approximated, and a Matlab/Simulink simulation model is built. The algorithm is designed and applied to an intermediate frequency inverter device, and the correctness of the proposed method is verified in the two aspects of simulation and experiment. ［Results］The simulation results show that the total harmonic distortion (THD) of the output waveform based on the tangent-secant midpoint approximation method is 2.64%, lower than the 3.99% of the symmetrical regular sampling method. The waveform quality of the tangent-secant midpoint approximation method is obviously better than that of the symmetrical regular sampling method, as it not only reduces the switching frequency but also takes into account the requirements of THD. ［Conclusions］SPWM sampling based on tangent-secant midpoint approximation is applied to the intermediate frequency power supply and is able to effectively overcome the shortcomings of the low-quality output waveform and high switching frequency of the symmetrical regular sampling method. Both theoretical analysis and engineering practice verify the rationality and correctness of the proposed method, and it can be widely extended to the field of intermediate frequency power supply installation. © 2022 Journal of Clinical Hepatology. All rights reserved.     

散货船水尺计量及货量保证方法探讨

散货船运输目前是国际海运的主力之一,其对海运业的发展起到了积极作用.但在运输中,散货船不同于油轮和集装箱轮,在校算货量时容易产生货量短缺的问题,如何确保每一航次的货量计算准确是船舶大副必须具备的业务知识,文章关于散货船水尺检验及货损货差方法给出了经验算法.