ZPW-2000A型自动闭塞计算机辅助设计系统

主要介绍了ZPW-2000A型无绝缘轨道电路自动闭塞计算机辅助工程设计系统的功能、结构及模块设计思想，并对主要模块的实现提出了建议。     

简支梁—柱弯矩扩大系数的研究及强度和稳定的统一算式的推算

本文导出了各种受力状态下压弯杆的弯矩扩大系数,提出了截面特性换算系数,使压弯杆“二次弯曲”问题转化为“一次弯曲”,稳定问题转化为强度问题,从而给出了统一验算公式。文中指出《铁路桥涵设计规范》(文中简称《桥规》)中存在问题,提出了修正意见。     

Study on fast calibration of a ULA＇s gain and phase error

Array calibration is important in engineering practice. In this paper, fast calibration methods for a ULA＇s gain and phase errors both in far and near fields are proposed. In the far field, using a single sound source without exact orientation, this method horizontally rotates the array exactly once, performs eigen value decomposition for the covariance matrix of received data, then computes the gain and phase error according to the formulas. In the near field, using the same single sound source, it is necessary to rotate the array horizontally at most three times, build equations according to geometric relations, then solve them. Using the formula proposed in this paper, spherical waves are modified into plane waves. Then eigen values decomposition is performed. These two calibration methods were shown to be valid by simulation and are fast, accurate and easy to use. Finally, an analysis of factors influencing estimation precision is given.     

浅析锚杆挡土墙的受力及计算方法

介绍了近年来广泛应用的轻型支挡结构———锚杆挡土墙的结构、发展、优势及其受力分析、计算方法,并运用南昆线百色至威舍段的锚杆挡土墙进行了验证,总结了锚杆挡土墙的受力特征及其施工质量控制。锚杆挡土墙在各种锚固工程中的应用有着广阔的发展前景。     

管幕内顶进箱涵时顶部管幕力学作用的试验研究

上海市中环线虹许路北虹路下立交工程是目前世界上在饱和含水软土地层中施工的横截面最大的管幕法工程。为了充分研究箱涵顶进过程中管幕的力学作用,根据相似理论,按照实际工程状况进行了室内模型试验,得到了箱涵推进过程中地面和顶部管幕的竖向位移,以及管幕下土压力的变化特征,发现箱涵前端一定范围内的地层主要表现为竖向沉降变形,顶部管幕在箱涵推进过程中起到一定的承载作用,这对于稳定箱涵前端开挖面是有利的。试验结果对实际工程的设计与施工提供了一定的参考。     

西太平洋航线温带爆发性气旋活动与天气海况分析

根据观测是统计和天气海洋资料,分析了西太平洋航线温带爆发性气旋活动的气修学特征,并结合个例考查了爆发性气旋的天气与海况特点。结果表明爆发性气旋具有不同于一般气旋活动的规律和天气海况特征,认识它们有助于减少或避免海损事故的发生。     

高强混凝土在工程中的应用

阐述了高强混凝土设计中的材料选择和配合比设计问题,同时介绍了高强混凝土在施工中应该注意的问题。     

Experimental research on spray and combustion characteristics of the third generation conical spray

A new generation conical spray system for conventional diesel engines or premixed combustion diesel engines is introduced. By means of oriented impingement method, flexible spray penetration in design is realized. High-speed photograph was used to investigate the spatial distribution characteristics of the new spray for cases of different impingement angles and needle valve opening pressures. The results show that, by applying spray impingement orientation, fuel jets spread along the cone surface as shape of sectors, so the dispersion of jets is increased obviously. Changing on impingement angle leads to variation of penetration, which is critical in homogeneous mixture preparation. Due to the flexibility of spray penetration in design, the spray impingement on liner is avoided in a great extent. The results also indicate that higher needle valve opening pressure results in longer penetration and larger spray angle after impingement. Combustion characteristics of the impinged conical spray were studied in the 1135 type diesel engine. The new impinged conical spray system work smoothly in full load range with better fuel economy and lower emissions of NOx and soot than the original test engine.     

Numerical simulation of three-dimensional combustion flows

A finite-rate method is used to simulate the three-dimensional combustion process in a plasma generator with CH4 as the fuel. The simulation was run with RNG k-ε model to simulate turbulence, with eddy-dissipation-concept （EDC） model to simulate the combustion and with discrete ordinates model to simulate radiation. The numerical results show that the flow field characteristics and the parameter distributions are under the condition of rich fuels, and these results provide valuable information when optimizing the plasma generator design and organizing its flow fields.     

A nonlinear model reference adaptive inverse control algorithm with pre-compensator

In this paper, the reduced-order modeling （ROM） technology and its corresponding linear theory are expanded from the linear dynamic system to the nonlinear one, and H∞ control theory is employed in the frequency domain to design some nonlinear system＇ s pre-compensator in some special way. The adaptive model inverse control （AMIC）theory coping with nonlinear system is improved as well. Such is the model reference adaptive inverse control with pre-compensator （PCMRAIC）. The aim of that algorithm is to construct a strategy of control as a whole. As a practical example of the application, the nunlerical simulation has been given on matlab software packages. The numerical result is given. The proposed strategy realizes the linearization control of nonlinear dynamic system. And it carries out a good performance to deal with the nonlinear system.