钢制焊接油罐罐体的垂直度控制要点

随着我国石油、化工产业的快速发展,其储存设备等也需要相应的增加。钢制焊接油罐是石油、化工产品等储存的主要设备,其制作安装的质量关系着石油化工产业的质量。对油罐体垂直度的控制是其制作安装的重点,本文从壁板下料精度、预制成型、组装、焊接变形等进行分析,探讨各自的控制要点,供相关人员参考。     

Damping of Oblique Ocean Waves by a Vertical Porous Structure Placed on a Multi-step Bottom

Oblique ocean wave damping by a vertical porous structure placed on a multi-step bottom topography is studied with the help of linear water wave theory. Some portion of the oblique wave, incident on the porous structure, gets reflected by the multi-step bottom and the porous structure, and the rest propagates into the water medium following the porous structure. Two cases are considered： first a solid vertical wall placed at a finite distance from the porous structure in the water medium following the porous structure and then a special case of an unbounded water medium following the porous structure. In both cases, boundary value problems are set up in three different media, the first medium being water, the second medium being the porous structure consisting ofp vertical regions-one above each step and the third medium being water again. By using the matching conditions along the virtualvertical boundaries, a system of linear equations is deduced. The behavior of the reflection coefficient and the dimensionless amplitude of the transmitted progressive wave due to different relevant parameters are studied. Energy loss due to the propagation of oblique water wave through the porous structure is also carried out. The effects of various parameters, such as number of evanescent modes, porosity, friction factor, structure width, number of steps and angle of incidence, on the reflection coefficient and the dimensionless amplitude of the transmitted wave are studied graphically for both cases. Number of evanescent modes merely affects the scattering phenomenon. But higher values of porosity show relatively lower reflection than that for lower porosity. Oscillation in the reflection coefficient is observed for lower values of friction factor but it disappears with an increase in the value of friction factor. Amplitude of the transmitted progressive wave is independent of the porosity of the structure. But lower value of friction factor causes higher transmission. The investigation is then carried out for the second ca     

Optimization of Wigley Hull Form in order to Ensure the Objective Functions of the Seakeeping Performance

The research performed in this paper was carried out to investigate the computational procedure to design seakeeping optimized ship hull form. To reach the optimized hull form, four stages should be done, which consists of： generate alternative hull form, seakeeping calculations, objective functions and optimization techniques. There are many parameters that may be determined in ship hull form optimization. This paper deals with developed strip theory for determining the seakeeping performance, genetic algorithm （GA） as optimization method, high order equations for curve fitting of the hull form and finally reaching to the minimum bow vertical motion in regular head waves. The Wigley hull is selected as an initial hull and carried to be optimized. Two cases are considered. For the first case, the only form coefficients of the hull （CB, CM, Cw, Cp） are changed and main dimensions （L, B, 7） are fixed. In the second case both hull form and main dimensions are varied simultaneously. Finally, optimized hull form and its seakeeping performances are presented. The results of optimization procedure demonstrate that the optimized hull forms yield a reduction in vertical motion and acceleration.     

微波信号LTCC多层互连设计

不同平面的微波信号低插损互连过渡已成为决定三维T/R组件性能优劣的关键问题之一,论文针对此问题介绍了一种窄带微波信号多层互连设计.该设计使用通孔垂直互连和带状线-微带线过渡,将电磁波从顶层微带线传输到底层微带线,从而完成异面微波信号互连.该设计运用三维高频电磁仿真软件HFSS建立并对比分析了三种模型,最后综合工艺难度和仿真结果挑选出最优方案加工成实物.经测试得到：在12GHz～18GHz范围内,插损小于0.9dB,回波损耗大于12dB,与仿真结果基本一致.实验结果表明,该结构具有尺寸小、插损低、应用范围广等特点.     

浅埋湖底隧道结构施工技术

南京玄武湖隧道 ,全长 2 6 6km ,隧道采用明挖法施工 ,主体为现浇混凝土结构 ,对隧道主体工程施工中遇到的无对拉螺栓支模、梁州段垂直支护结构施工、结构防水等难题 ,就其关键技术进行简单阐述     

哈达铺隧道Ⅵ级围岩浅埋段施工技术

哈达铺隧道下穿铁匠沟浅埋段软塑淤泥质黏土为Ⅵ级围岩,承载力低,在施工扰动后很难形成稳定受力圈,施工难度大。地表做排水沟对地表水引流,防止渗入隧道内。采用地表注浆加固隧道范围内围岩,增强其自稳能力,高压喷射注浆将浆液注入松软的岩土,胶结后形成一个强度较高的新岩土体,隔离了淤泥物,提高了隧道基底承载力,使原来软弱层得到良好的加固,有效控制了隧道变形及地表沉降,满足了施工需要。     

高速铁路分段垂直矩形天窗设置的探讨

目前,我国高速铁路日常综合维修主要采用分段垂直矩形天窗的形式,天窗对长途跨线列车的影响远远大于本线列车。通过对相邻天窗分段交错时间采用图解法进行分析,研究发现：天窗分段的长度和交错时间是影响顺向跨线列车运行的主要因素,列车运行时分最长的天窗分段限制了分段垂直矩形天窗对顺向跨线列车的影响范围,其影响范围等于天窗限制区段的天窗开设时长与运行时间之和。在对三个相邻天窗分段开设的情况进行研究的基础上,得出了最小天窗影响时段的天窗交错时间取值范围。     

基于船联网的异构网络垂直切换信号预测技术研究

针对内河航运中存在多种异构网络共存的现状,提出了1种网络状态共享机制,即由信息中心收集来自船舶的网络状态信息,然后进行汇总处理后将数据共享.运用灰色理论,并根据船舶网络状况历史数据,与信息中心的最新数据相融合,得出较准确的前方网络状况值.通过Matlab仿真,验证了这种信号共享方法及预测机制可以有效提升预测信号的准确度,并同时兼顾了船舶的速度和长距离预测问题,适用于船载终端.     

荷兰OBA码头桥式抓斗卸船机简介

为提高生产效率,上海振华重工为荷兰阿姆斯特丹OBA码头设计制造1台桥式抓斗卸船机。该机作业速度在当前卸船机中最快,并设有抓斗旋转、门框铰轴系统、双出口漏斗双给料皮带机等新型功能。可为卸船机多元化的技术提供参考。     

SQS⁃300型隧道桥梁清筛车技术方案及应用

针对既有有砟轨道线路中作业面宽度较小的隧道、桥梁段道砟机械化清筛难题,设计了SQS?300型隧道桥梁清筛车.采用倾斜式挖掘装置或垂直式挖掘装置,实现最小挖掘宽度3100 mm(Ⅱ型枕)、3200 mm(Ⅲ型枕);采用道砟综合回填技术,大幅减少人工辅助,缩短辅助作业时间;采用具有自动控制功能的主辅起拨道装置进行线路挖掘前...