系统发生的

After the collision, Shanghai Municipality organized an investigation group for this accident and came to a conclusion in a shortest possible time: it is an omission in the design that caused a wrong instruction, so the down-train directly collided with a normal turn-back train on the side due to insufficient braking distance, and the accident thus happened.

事故发生后，上海市政府迅速组成事故调查组，并在最短时间内对事故作出了结论。事故的直接原因是：由于设计疏漏，造成信号系统发出错误指令，致使列车制动距离不足，使下行列车与正在折返的列车发生侧面冲撞，导致了该事故的发生。

The main research work of this paper are focused on following areas:(1) Based on review of the theory and methods on measurements of particle fields, a new idea for obtaining particle size and velocity distribution within a spray through imaging the particle field with a laser light sheet was put forward;(2) A DPIV (Digital Particle Image Velocimetry) system, is fit for velocity measurements of low speed flows, was developed and expended to particle size distribution measurement;(3) An arithmetic for particle velocity field reconstruction was developed, and the velocity distribution of water mist was also obtained;(4) A software system for particle analysis, which based on image geometry emend, de-noise and image partition was developed, the parameters such as particle size distribution, mean diameter, number of particles, minimum and maximum diameter can be got with this system;(5) A water mist system was developed and its characteristics, such as droplet velocity, size distribution, number of droplets and spray cone angle under different conditions were obtained from experiments with PIVS;(6) The measurement results of water mist characteristics with PIVS were compared and analyzed with the simply simulated results, and in addition, in order to verify the accuracy of PIVS, some experiments were conducted with the standard particles, such as glass-ball with known mean diameter of 50μm and 115μm, metallic coated tracing particle with mean diameter of 12μm;(7) Some experimental studies on interaction of water mist with liquid pool fires were conducted.

本论文的主要工作包括以下几个方面：（1）在对粒子场测量的相关理论和具体方法进行综述分析的基础上，提出了通过采用激光片光对粒子场进行成像以获取其粒径和速度等参数分布的新思路；（2）研制了适宜于低速流动速度场测量的DPIV(Digital Particle Image Velocimetry)系统，并使其实现了对粒子场粒径分布的测量功能；（3）研制了基于粒子运动轨迹的速度场重建算法，获取了细水雾雾场的速度分布；（4）研制了基于几何校正、去噪、图象分割等图象处理方法的"粒度分析软件系统"，该系统既可分析给出粒子场的粒径分布直方图和平均粒径，还可给出粒子的数目以及最大、最小粒径等信息；（5）建立了一细水雾发生系统，并应用上述方法对不同压力条件下细水雾系统的雾场特性（如速度分布、雾滴粒径分布、雾滴的数目、喷雾张角以及雾化长度等）进行了实验测量研究；（6）对细水雾特性参数的PIVS测量结果与计算机简单模拟计算结果进行了定性比较分析，并利用平均粒径为50μm和115μm的玻璃球以及12μm的标准示踪粒子对PIVS系统的粒径和速度测量结果进行了实验验证，同时对其局限性进行了分析讨论；（7）对不同工况条件下细水雾与油池火相互作用的过程进行了模拟实验研究。

The objectives of this study were to develop a wireless sensor network technologies for agrometeorological disaster early alarm system and processing system. In this study, the foehn with a high temperature and low humidity has been monitored. The wireless sensor acquisition module ZigBee has been used to monitor the climate conditions combined with a GPRS wireless transmission module to construct wireless disaster alarm sytem. Graphical programming computer software package LabVIEW 8.2 was used to develop the control and monitoring systems.

本论文研究目的旨在发展气象灾害预警及处理系统，以焚风灾害为研究对象，焚风为台湾农业气象灾害之ㄧ，每年发生次数频繁且不可预测，当焚风发生时，监控焚风产生的高温和低湿变化，透过ZigBee无线传输技术，可连结温湿度、光度及土壤含水率等感测器，并与GPRS模组结合，将资料即时传送至伺服平台，藉由LabVIEW程式监控环境变化，达到气象环境即时监测之目的。

Analysis with numerical simulation shows that the equilibrium may not change its stability at all or changes its stability up to a finite number of times.

研究表明，系统在不同参数控制下，平衡点的稳定性可以不发生改变，也可以发生多次稳定性切换。

And this causes a frequency change Δf. The resonant point tracing algorithm describes how to detect Δf. So it can introduce a feedback frequencydifference -Δf through a closed loop to realize the resonant state o In the digitaldetection scenario, using staircase wave to replace saw tooth wave, it can overcome a lot of shortcomings in the analog system. The character of the staircase wave affects the detection precision directly. This thesis analyzes a high precision scenario producing a staircase waveform in detail. It can reduce the number of the bits in D/A converter greatly. This thesis proposes another method to improve the detection precision in case that the A/D converter has comparatively little number of bits, while this method will not increase the cost of the system greatly.

在谐振式光纤陀螺中，环形谐振腔的旋转使得谐振腔的谐振频率发生了变化，从而产生了一个与旋转速度成正比的频率变化值△f，谐振点跟踪算法描述了如何检测出△f，从而可以通过闭环在系统中引入反馈频差-△f，实现光路的谐振状态；在数字闭环检测方案中，用阶梯波作为反馈信号来代替锯齿波，可以克服原来模拟系统中锯齿波的很多缺点，阶梯波的性能直接影响着系统的测量精度，本论文详细分析了一种高精度阶梯波生成方案，使得所需D／A的位数大大降低；本文还分析了A／D转换器对系统测量精度的影响，提出了一种A／D转换器位数较少的情况下提高系统测量精度的措施，同时又不会增加太多的系统成本。

The inverse model of the system which can be established by neural network according to the UAV's movement is connected with the object controlled so that the nonlinear and correlative system will become linear and irrelated. PID reactive control is used to improve the performance.

根据无人机发生故障时非线性运动的特点，确定适当的神经网络结构建立无人机非线性系统的逆系统，并与被控对象串连可以对非线性耦合系统进行线性化解耦，然后引入PID反馈控制进一步提高神经网络逆控制系统的性能。

Systematic investigations were performed of impact factors influencing the plant regeneration of Medicago sativa, in order to establish a regeneration system with high efficiency for genetic improvement.

通过系统地对紫花苜蓿体细胞胚发生以及次生胚发生途径中若干影响因子的比较研究，建立了紫花苜蓿高频体细胞胚和次生胚再生体系。

Taking the development platform of HVDC power transmission for example, the calculation result of impedance-frequency characteristic of traditional line commutated converter and that of FCC are compared. Simulation results show that the impact of impedance-frequency characteristic of converter on the resonance frequency of AC system is not negligible, and FCC can enhance the strength of AC system in a certain extent, improve system stability and effectively reduce AC equivalent impedance under resonance frequency, thus the harmonic instability of HVDC power transmission system can be avoided.

以直流输电开发平台为例，对传统电网换相换流器(line commutated converter，LCC)与FCC的阻抗频率特性计算结果进行对比，仿真结果表明换流器的阻抗频率特性对交流系统的谐振频率有着不可忽略的作用，FCC在一定程度上提高了交流系统强度，改善了系统稳定性，有效降低了系统谐振频率下的交流等值阻抗，从而更好避免直流输电系统谐波不稳定现象的发生。

The mechanism of instability wrinkling in the process based on minimum energy principle is revealed, uniform mathematic description of the wrinkling wave on the strip of in-plane bending is established, the internal and external energy is deduced by energy method, and a uniform criteria of internal and external wrinkling is established; then how to combine the criteria with the FEM simulation system to make the numerical prediction of wrinkling into reality is also resolved in the paper. The effects of the forming parameters on the deforming result are analyzed by the uniform predict criteria. The results show as follows: as the compress width increase, external wrinkling first come into being, then internal winkling do, and finally in-plane bend occur; the loading wedge angle increase, internal winkling first come into being, thenin-plane bend do, and finally external wrinkling occur; in-plane bend is possible to occur with a increase of the strain-hardening exponent and the strength coefficient; and the effect of the friction factor may be ignored.

2揭示了板带不均匀压下面内弯曲成形过程基于能量原理的失稳起皱机理，提出了统一的描述内外缘起皱波形的函数，采用变分法推导了服从该波形函数的内外缘起皱能，建立了统一的起皱预测准则；将新建立的统一的起皱预测准则引入到数值模拟系统IBS中，数值预测结果与实验结果的吻合较好；分析了成形过程各参数对起皱的影响规律：随着接触变形区宽度的逐渐增大，先是发生外缘起皱，然后发生内缘起皱，进而才出现稳定成形；随着实际加载楔角的增大，先是发生内缘起皱，然后发生稳定成形，进而出现外缘起皱；硬化指数和强化系数增大，易于稳定成形；摩擦因子对起皱的影响不明显；而且接触变形区宽度对起皱的影响最大。

The paper mostly studies the super-high pressure abrasive water jet technology in following several aspect:At first, the structure of water jet beam as well as its characteristic and mechanism in cutting different kinds of material were discussed.

本文主要从以下几个方面对超高压水射流进行了研究：高压水射流与超高压磨料水射流的射流结构与形成原理；切割不同性能材料的切割机理；切割系统的控制；超高压水的发生原理及发生装置；在此基础上又通过基础实验与应用实验总结出切割不同材料过程中，切口形状的变化、影响切割表面的质量的各种因素及改善切割表面质的的措施；并对实验所用系统的计算机辅助设计过程与M软件的使用进行了介绍。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。