模拟

The paper first constructs the relating technology framework between coal low temperature self-heating thermal properties parameters and spontaneous combustion, by means of testing on coal samples of diffusibility relative to oxygen, gas-producing simulation in self-ignition process, adiabatic oxidation process, coal spontaneous combustion processing simulation, coal basic physical and chemical parameters, thermal analysis by differential scanning calorimeter , differential thermal analyzer , Thermogravimeter .

通过对试验煤样进行煤对氧的扩散特性试验、煤自然发火过程中气体产物模拟实验、DSC差示扫描量热热分析测试、DTA与TG热分析测试、煤自然发火绝热氧化过程试验、煤自然发火过程模拟试验、煤基础物理化学参数测试的试验研究，就煤对氧的扩散与吸附特性、煤自燃氧化过程中的热力特性与气体产物特性及其与煤自然发火过程之间的相关特性进行了较系统的研究，初步建立了煤低温氧化自热热物理特性参数与煤自然发火之间相关联的技术内涵。

In the analysis of the circuit, the differential equation based on the theory of electromagnetism had been established; the circuit qualitatively had been analyzed, and the current on the coil in the process of experiment had been calculated.

在电磁压制放电电路的模拟分析中，基于电磁学理论建立了放电过程的微分方程，对电路作了定性的分析；通过对实验参数的模拟，求解出实验过程中线圈上的载荷电流。

Equilibrium Molecular Dynamics Simulation was performed for water to calculate its diffusivity by using different potential models.

本文选用平衡分子动力学模拟方法，应用不同的势能模型对强极性分子水的扩散系数进行了模拟计算。

Circuit principles, analogue circuit, digit circuit which laid me a solid foundation of circuit for the study of communication; the study of electronic circuit of communication provided me with the working principles of analog communication system; the study on communication theory made me grasp the working methods of digital communication; the study on electromagnetic field, electromagnetic wave and aerial let me know that how signals travel through signal paths and how to apply signal and linear system, random signal and system to the research of noise's impact on signals

学习了电路原理、模拟电路、数字电路打下了学习通信的电路基础；学习了通信电子线路掌握了模拟通信系统的工作原理；学习了通信原理掌握了数字通信的工作方法；学习了电磁场与电磁波、微波与天线了解了信号如何在信道中传输；学习了信号与线性系统和随机信号与系统来研究噪声对信号的影响。

According to the demand of high magnetic field power supply, reference is increased with a set ramp rate and stops at a set stable value, so reference system is composed of digital setting and digit to analog converting circuit. But the stability of reference is mostly guaranteed by the performance of D/A circuit, so D/A circuit is particularly studied in reference system. The scheme of D/A circuit, the selection of DAC and its voltage reference, hardware anti-jamming design and PCB design are discussed in detail, and software of remote control and PLC are discussed in brief. Zero-flux DC current transformer well satisfies the demands of the high stability of Load current detection unit, so the principle of zero-flux DC current transformer is analyzed; in the mean time a project which detects the long term stability is designed. During 8 hours, analog signal which is detected with high precision digit multimeter is recorded in computer at 1HZ frequency by GPIB communication. The drift error source and related parameters are explained in the compare-amplify part. Detailed subtraction circuit is designed; also amplifier chip and periphery components are selected and verified according to the theory of error analysis.

根据强磁场电源的需求，参考源应按照软件设定的斜率逐渐上升到设定稳态值，则参考源系统应由数字给定和数模转换电路两大部分组成，而参考源的稳定度主要依靠完成数模转换功能的模拟电路的性能来保证，因此本文对参考源系统的研究以数模转换电路为重点，分别从电路方案的确定、数模转换芯片及其基准电压源的选取和验证、电路板硬件抗干扰和PCB设计几方面进行了论述，然后对数字给定部分的远控组态和PLC程序设计作了简要介绍；采用零磁通原理的直流电流转换器很好地满足了对负载电流检测单元高稳定度的需求，本文详细分析了零磁通检测的原理，并在选定此种类型电流转换器的基础上设计了一套检测长期稳定度的方案，8小时内以1秒为采样周期，通过计算机Labview程序和高精度数字电压表的GPIB通讯，将被高精度数字电压表数字化后的模拟信号采样值连续记录至计算机中；比较放大环节简要阐述了漂移产生的原因和相关参数指标，确定了具体的减法电路形式，并根据误差分析理论对运算放大器和外围元器件进行了选取和验证。

As a private mobile communication system, The digital trunkingmobile communication system was boomed in 1990's, and before this, the appliedprivate mobile communication systems in market are almost the analog systemwith analog voice and digital signalling. And there are no data referring to thesystem design and parameters chosen. It includes the wireless channel accessalgorithm of the mobile terminals, single base station capacity in large regional networks, link designing schemes between the switching control center and basestation as well as the study of the service quality for the multiple traffic. Theseindispensable parameters in design a digital trunking communication system arestudied in this dissertation and some instructive achievements can be got. To provethe correction of the theoretical study, the result was tested with the popularsystem of pan-European digital trunking communication system.

数字集群移动通信系统是九十年代中、后期兴起的专用移动通信系统的一种新体制，在此之前国际、国内市场使用的都是数字信令、模拟话音集群移动通信系统其涉及领域是模拟体制，对数字集群的系统设计的有关参数、方法等的选用及其性能表现并无成熟的文献可供参考，如移动终端的无线信道接入算法、大区组网单基站系统的容量、基站和交换控制中心间的链路设计和多业务种类的服务质量等都是数字集群基站子系统进行设计和开发必须解决的关键技术。

Traditionally, the numerical simulation studies of gas-solid turbulence flow are based on Reynolds-Averaged models which are not able to get accurate results. While with the rapid development of computer science, direct numerical simulation method becomes more and more vital hotpoint.

传统的研究气固两相湍流数值模拟是基于平均的思想，其无法描述流动的精确结构等缺点让直接数值模拟的方法在这个方面随着高性能计算机的出现而飞速发展。

The direct numerical simulation method was applied to an industrial scale entrained flow coal gasification radiant syngas cooler to simulate three-dimensional multiphase flow field and temperature field.

通过直接数值模拟的方法对实际气流床煤气化辐射废锅内三维多相流流场和温度场进行了模拟。

In this dissertation, research work of near-field numerical simulation is briefly reviewed, some existing problems are analyzed, and the following problems in decoupling numerical simulation, which is a key research direction in present, are studied.

本文简要地回顾了近场波动数值模拟的研究工作，分析了存在的问题，并针对当前的一个主要发展方向—数值模拟的解耦技术，对下列问题进行了研究。

The topic in view of the existing technique level, the main factors, which influence the measurement precision of the large scale test system, are analyzed in this paper, and the solutions improving the precision are put forward.1 using the multi-channel independent AC to transfer DC module, the power supply of the digit part and the simulation part is discerption, reducing the crosstalk between the digital signal and the simulated signal;2The feedback self-checking module is constructed by singlechip compositive 16 high accuracy A/D , established a closed-loop control system through this module and improved system's overall precision effectively.

本课题针对现有的技术水平，分析了影响大型检测系统测量精度的主要因素，提出了提高精度的具体方案和办法：1采用了多路独立交流转直流模块，数字部分与模拟部分分开供电，减小了数字信号与模拟信号之间的串扰。2利用单片机集成的16位高精度A/D构建了反馈自检模块，通过该模块建立了一个闭环控制系统，有效地改善了系统的整体精度。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。