对比法

The basic approach of protecting people from being hurt or killed in an accident is to improve crashworthiness of vehicles. This paper starts with discussing theories and methods for vehicle passive safety design, which included experiential methods, analytic methods, multi-body dynamics methods, crash test methods and the finite element method. Emphasis will be paid to the basic FEM theories and algorithms of impact problems. Topics discussed include the governing equation, element discretization, hourglass control, time integration, material model, shell element algorithms and contact-impact algorithms. For more reliable simulation results, this paper then conducts study on how to accurately get material model parameters by combining the FEM method with experimental method, and develops relevant material test machine and parameter calculating software. Based on that, basic typical impact simulation and test validation study are conducted. On the basis of the above work, the paper studies the thin-shell structures'crashworthiness, which was affected by the following factors: spot-weld features, shell thickness, cross-section and pre-deformation. As to vehicle parts'crashworthiness, the paper conducts simulation study of designing energy-absorbing steering system and adaptive airbag system. A practical energy-absorbing steering wheel is designed as an example. In further depth research, the paper suggests several inverse quantificational methods for vehicle crashworthiness design based on the ideal crash characteristics. The above theories and methods are applied with good results through several practical vehicles' crashworthiness design and improvement.

文中对汽车碰撞安全性的设计理论和方法进行了归类和总结，其中包括经验法、解析法、多刚体动力学法、试验法以及有限元方法等；重点介绍了碰撞有限元法的基本理论和有关算法，涉及到有限元求解控制方程、单元离散、沙漏模态控制、时间积分、材料模型和应力修正、薄壳单元算法以及接触碰撞界面算法等，探讨了有限元计算中的材料模型参数获取技术，开发了相应的材料试验装置及材料模型参数反求软件，在此基础上进行了基本的碰撞仿真算例和试验对比研究；文中通过应用有限元方法研究了薄壁构件的碰撞吸能特性，指出了设计薄壁吸能构件时需要考虑的几个主要影响因素，即焊点、壁厚、横截面和预变形等；在关于车辆部件的碰撞安全性能设计中进行了吸能转向机构和自适应安全气囊的仿真研究，提出了吸能转向机构和自适应安全气囊的仿真研究方法；文中最后探讨了整车碰撞性能的设计与改进方法，提出了以理想碰撞特性为目标，采用分段加速度或者根据碰撞时间进行设计的反推设计法、部件吸能仿真优化设计法等量化设计方法，并通过综合应用文中所讨论的相关技术进行了整车碰撞性能的设计与改进实例研究，所选定的车型是大众化的普通轿车和碰撞安全性基础较差的微型面包车，研究结果表明，本文所提出的设计与改进方法是适用而有效的，具有重要的工程实用意义和价值。

The following points are emphasized:The operation models of adiabatic and diabatic distillation have been set up and the operation block, thermodynamics model and mathematical model in the simulation have been determined as well;(2)Based on the simulation and exergy analysis with Aspen Plus program, shortcut distillation design—DSTWU model and rigorous distillation design—RADFRAC model, the author has determined the heat duty, exergy losses and the distribution of exergy losses along the adiabatic column, which will help the simulation and optimization of the diabatic distillation;(3)Diabatic distillation under various operation conditions has been simulated by using energy balance method and exergy analysis;(4)How the different mixture and the various degree of separation, number of trays and feed location influence exergy saving in diabatic distillation have also been discussed;(5)On the basis of the total exergy losses along the column, different schema of the heat transfer distribution along the column have been compared and analyzed;they can be classified in three categories: heat duty equipartition approach, empirical approach, separation degree matching approach. In conclusion, different heat transfer distribution along the column will have effect on total exergy losses. In particular, most satisfactory results have been obtained by using separation degree matching approach. In order to diminish the exergy losses, heat transfer distribution should meet the needs of the request of separation degree.And on this premise, the author makes his suggestion in increasing the proportion of heat supplied to the tray with minimum exergy losses and decreasing the proportion of heat supplied to the tray with the maximum exergy losses.

本文对透热精馏过程进行了模拟并对其节能效果的影响因素做了较为全面的分析和深入的研究，主要研究内容如下：(1)建立了常规精馏和透热精馏过程的模拟操作模块、热力学模型以及数学模型；(2)利用化工模拟软件Aspen Plus并分别采用DSTWU简捷模型和RADFRAC严格计算模型对常规精馏进行模拟计算和有效能分析，确定常规精馏塔的公用工程热负荷、有效能损失及有效能损失在塔内的分布，为透热精馏的模拟和优化提供数据参考；(3)对不同物系在不同分离度条件下进行透热精馏的模拟，分别采用能量衡算法和有效能分析法进行计算和分析；(4)探讨了各种因素如物系的选择、不同分离度、塔板数、进料位置对透热精馏节能效果的影响；(5)以全塔总有效能损失为比较基准，对热量在塔内的三种分布方案即热负荷平均分配法、经验法和分离度匹配法进行了对比分析并得出结论：塔内热量的不同分布方案对于全塔总有效能损失会产生影响，其中以分离度匹配法的节能效果最为理想，为减少有效能的损失，应使塔内的热量分布满足各塔板的分离度要求，并在此前提下，尽量减小有效能损失大的塔板的热负荷和增加有效能损失小的塔板的热负荷。

To study the sweetening process of diasporic bauxite,Al3 obtained from the direct carbonization of unrefined sintering solution was used as the additive and its performance was compared with that of the conventionally used gibbsite .

分别以烧结法粗液直接进行深度碳分所得到粗氢氧化铝和工业上常用的三水铝石矿作为添加剂，进行了一水硬铝石矿增溶溶出过程的对比研究，主要考察了增溶温度、添加剂添加量和增溶时间等因素对溶出效果的影响，同时对增溶溶出矿浆与常规拜耳法溶出矿浆的沉降性能进行了对比研究。

Directed against the existing problems in traditional mixing process, secondary mixing techniques, such as pre-mix cement mortar, pre-mix cement paste, sand enveloped with cement paste, coarse aggregate enveloped with cement paste and aggregate enveloped with cement paste are discussed, and the effect of different mixing technological processes on concrete mixing quality is studied. The homogeneousness, compression strength of concrete and the power consumption are tested during the test, and compared with the traditional mixing method.

针对传统混凝土搅拌工艺中存在的问题，讨论了先拌水泥砂浆法、先拌水泥净浆法、水泥裹砂法、水泥裹石法、粗细骨料全造壳法等二次搅拌工艺，研究了不同工艺流程对混凝土搅拌质量的影响，测试了不同条件下混凝土的匀质性、抗压强度指标及功率消耗，并与传统搅拌工艺进行了对比试验。

This dissertation firstly introduces the principles of four kinds of simple gridding methods, which are"Linear interpolation based on triangulation","Inverse distance weighted and averaged method","Modified Shepard's method"and"Multiquardirc method". Secondly, it researches the Ordinary Kriging method for geophysical irregular data, which mainly includes the base knowledge of region change and variogram and the principle of Ordinary Kriging method. Thirdly, it researches the Inverse Interpolation for geophysical irregular data, which mainly includes the principle of inverse interpolation and its iterative algorithm, and the principle of Inverse Interpolation to realize the gridding of geophysical data. Finally, it uses these gridding methods to grid theoretical model data of potential field and raw aeromagnetic data, and compares and analyzes the gridding results.

本文首先简单介绍了地球物理不规则分布数据的四种简单网格化方法(即基于三角网的线性插值法、反距离加权平均法、改进的Shepard方法和多元二次函数法)的方法原理；接着，重点研究了地球物理不规则分布数据网格化的普通克里金法，主要研究了区域变化量、变差函数的基础知识和普通克里金法的方法原理；之后，重点研究了地球物理不规则分布数据网格化的反插值法，主要研究了反插值法的方法原理和迭代求解算法，以及反插值法实现地球物理数据网格化的原理；最后，应用这些方法对理论位场模型和实际航磁数据进行了试验、对比和分析。

Based on the inverse mapping with linear deformation, the geometric mapping was used to carry out the second element transformation in order to avoid the abnormality of the stiffness matrix and to improve the stability and the convergence of the numerical calculations.

在现有线性变形逆向映射法的基础上，采用几何映射法计算变换单元，避免单元刚度矩阵出现畸形，提高钣金展开有限元逆算法的稳定性和收敛速度，对几何映射法与投影法所计算的变换单元进行了对比，数值计算结果表明用几何映射法计算的初始估算展开料形状更接近于最终的钣金件展开形状。

This paper analyzes log responses of tight formation s and tight gas reservoirs, correlates vertical formations in a same well and lateral formations in different wells and intra-formational response as well, uses graphic calibration method, analyzes the characteristics of logging curves of tight formation s from different perspectives, and thus determines gas potential of tight formation .

在对致密地层和致密气层测井响应特征进行分析的基础上，利用同井纵向对比观察、不同井横向对比观察、层内对比观察分析及图形刻度显示法，从不同角度分析了致密地层测井曲线的变化特征，进而确定了致密地层的含气性，取得了较好效果。

Through the experimental study of existing evaluation method of mud cake compressibility, this paper compares the compressibility under normal temperature static / dynamic state, with three evaluation methods "cake percotation rate ","penetrometer", and "two stage water loss".

本文通过对现行评价泥浆泥饼压缩性的三种方法："泥饼渗透率法"、"泥饼针入度法"、"两次失水法"进行对比实验研究，考察了在常温静态和高温静态四种实验条件下泥浆泥饼可压缩性之间的对比关系。

Based on the analysis of similarities and differences between core data, well log and seismic prospecting, the thesis makes a primary match between them;(2) Through layer boundary dividing by Walsh transformation, lithology determination by gray system and stratigraphy correlation by dynamic waveform match, an application to the aimed area was done;(3) This paper also gives the research on the character of well logs and reservoir parameters. According to the FBM protype, the profile of density and acoustic value between two wells was built. And the result showed good accordance with real logs.(4) By means of fractal reconstruction, it rebuilt the three dimensional shapes of the main stratigraphy boundaries in the studied area.

在详细分析总结岩心、测井和地震数据异同点的基础上，对三种数据进行了初步的匹配；②通过对测井曲线的沃尔什变换分层、灰色关联法岩性判别，综合多种动态层序对比技术，增改对比过程所需要的参数，进行了井间地层对比方法的探讨与应用研究；③详细研究了测井曲线以及储层参数分布的分形特征，以分数布朗运动为原型模拟出两口井中间对应地层的密度和时差参数剖面，结果与验证井数据表现出了良好的一致性；④采用分维重建方法再现了研究区块泉头组顶底面以及登二段底面的空间形态。

Methods 24 patients known to suspect of having pulmonary embolism underwent MCTPA with 20 ml contrast medium. Scanning delay time was adjusted by using a test bolos. Contrast medium injection rate was 5.5 ml/s. The time of imaging data acquisition was 2-3 s. In addition 24 patients undergoing MSCTPA with 50 ml contrast medium were included in control group. Imaging quality was evaluated by five degree with blind method.

应用多层螺旋CT对24名疑似肺栓塞的病人行CTPA检查，对比剂总量为20 ml(300 mgI/ml)，以单层动态增强扫描所测时间－密度曲线的峰值时间为扫描延迟时间，对比剂注射速率5.5 ml/s，数据采集时间2~3 s；另随机选择24例常规对比剂剂量(50 ml) CTPA检查影像作为对照组，影像质量按5级行盲法评价。

Life. But the intrinsic way of the Internet by wire confines accessing and using of the network information.

然而，Internet固有的有线连接方式大大限制了人们对网络信息的访问和使用。

I have a strong persuasion that this is true .

我坚信这是正确的。