散粮皮带机打滑开关的选配

日照港是国内主要的大豆集散枢纽,目前散粮系统拥有皮带机30余条,投产4年来,已接卸大豆达800余万吨。随着生产任务越来越重,设备利用率越来越高,胶带的损耗和故障率也随之增高。     

新长火车渡轮的设计介绍

主要介绍长江火车渡轮的船型特点.     

Modbus在某拖动控制系统中的应用

本文先介绍Modbus现场总线的通讯协议原理,对ASCII和RTU两种传输方式进行了分析,然后介绍了Modbus在某拖动系统监控系统中的应用,对不同厂家PLC之间的Modbus通讯进行详尽的介绍,包括设置和通讯软件编制。     

沥青路面抗滑表层研究综述

介绍了国内外抗滑表层的主要形式,论述了沥青路面抗滑性能的研究历程、研究现状以及存在的问题,提出了进一步研究的方向。     

基于影响矩阵法的自锚式悬索桥施工张拉力确定

自锚式悬索桥施工过程中,控制吊杆施工张拉力,使桥梁在施工完毕后达到理想的设计状态.文中结合自锚式悬索桥施工过程中的力学特性,提出了基于几何线性、几何非线性的影响矩阵法确定自锚式悬索桥的施工张拉力.该方法计算简单,所得结果符合要求.     

弯曲孔道摩阻预应力损失试验研究

预应力混凝土桥梁结构过大的预应力损失,导致桥梁结构过早的失效或破坏.预应力钢绞线与孔道壁之间的摩阻是预应力损失的主要因素.文中针对预应力混凝土结构设计中弯曲孔道引起的预应力损失问题,通过对接触正应力的理论分析,指出了现行预应力混凝土结构设计中接触正应力假设的不合理性.利用试验方法,研究了不同张拉力、不同接触面夹角θ与摩擦力矩之间的关系,说明了弯曲孔道引起的预应力损失随着外力的增加迅速增大,是引起结构预应力损失的重要因素,从而指出了现有结构设计方法的严重不足和对结构预应力损失计算所带来的偏差.     

Study of hierarchical federation architecture using multi-resolution modeling

This paper aims at finding a solution to the problem aroused in complex system simulation, where a specific functional federation is coupled with other simulation systems. In other words, the communication information within the system may be received by other federates that participated in this united simulation. For the purpose of ensuring simulation system unitary character, a hierarchical federation architecture (HFA) is taken. Also considering the real situation, where federates in a complicated simulation system can be made simpler to an extent, a multi-resolution modeling (MRM) method is imported to implement the design of hierarchical federation. By utilizing the multiple resolution entity ( MRE ) modeling approach, MRE for federates are designed out. When different level training simulation is required, the appropriate MRE at corresponding layers can be called. The design method realizes the reuse feature of the simulation system and reduces simulation complexity and improves the validity of system Simulation Cost (SC). Taking submarine voyage training simulator (SVTS) for instance, a HFA for submarine is constructed in‘this paper, which approves the feasibility of studied approach.     

现代COUNTY客车电子定时报警控制系统

简要介绍ETACS（Electronic Timing Alarm Control System）对刮水器电机的间歇、洗涤器、安全带、倒车镜加热、预热器系统等的定时报警控制过程及原理。     

Experimental and Numerical Study on the Behaviors of Deep-Buried Water-Storage and Drainage Shield Tunnels北大核心CSCD

Deep-buried water-storage and drainage shield tunnels, which are different from road and subway shield tunnels in terms of computation theory, construction technology and operation maintenance, would bear high inner water pressure and large earth pressure. In view of the change of the bearing mode for the lining structure of water-storage and drainage shield tunnels, a full-ring test and numerical analysis are carried out to study the influence of inner water pressure, staggered joint assembly and bolt installation types on the behaviors of water-storage and drainage shield tunnels. The results show that the deformation of the straight-jointed water-storage and drainage shield tunnel varies greatly from the state of empty water to that of full water; and the vertical and horizontal convergence deformations of the tunnel with inner water pressure of 0.6 MPa are 2.2 times and 3.2 times of that without inner water pressure, respectively. The convergence deformation, and the maximum joint opening and bolt tension of stagger-jointed lining structure decrease by 15%-25% and 25%- 40%, respectively, compared with that of the straight-jointed water-storage and drainage shield tunnel. The bolts at the segmental joints will yield because of the increase of inner water pressure and the first occurrence of bolt yield phenomenon is located near the position on the lining structure which is under the action of maximum negative bending moment; because the failure of shield tunnel is always caused by the yield of joint bolts, this position is the weak point for the deep-buried water-storage and drainage shield tunnel. For the water-storage and drainage shield tunnel based on the connection with double rows of bolts, the bolts near the outer arc surface of segmental joints in the area of 90 degree in the vault and arch bottom can be removed; the bolts near the inner arc surface of the segmental joints within the 90 degree of the haunch must be installed, otherwise, the tensile force of the bolts at the segmental joint near the maximum negative bending moment will increase by 5%-14%. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

海洋平台大型生活区模块吊装方案设计及优化研究

海洋平台大型生活区模块整体吊装是其建造过程中一项先进工艺,如何保证其吊装工艺的安全可靠更是一项关键技术。本文以某海洋平台典型生活区模块为例,对其整体吊装方案进行了详细设计,采用有限元法和结构力学相关理论,结合规范对整体吊装强度进行了分析,发现了吊装过程中结构关键部位的薄弱环节,对其进行了吊装方案优化设计,并对优化后的整体结构再次校核分析,验证了吊装优化方案的可行性与准确性,为海洋工程大型模块吊装方案提供了可行的依据。