计算机辅助设计

The relevent concepts of tensor analysis into the study of computer aided tolerancing are introduced,and the general method for seeking the sencitivity coefficients of the mechanical problems with explicit constrains is derived.

把张量相关概念引入计算机辅助公差设计的研究中，导出显含约束、具有普遍意义的敏度系数求取方法。

Experiments show that C-B spline curve, uniform B-spline with shape parameter, hyperbolic polynomial uniform B-spline with shape parameter and trigonometric polynomial uniform B-spline with shape parameter can be used to produce some frequently used free form curves in the industrial field when the shape parameter is assigned with some specific values.

通过调整形状参数来修改曲线形状是计算机辅助几何设计中一个非常活跃的研究课题，研究形状参数的变化对样条曲线形状的影响，对于增加曲线造型的灵活性是非常必要的。

As an example to cubic trigonometric polynomial Bézier,the characters of trigonometric polynomial Bézier curve is analyzed,and deduced that cubic trigonometric polynomial Bézier curve is more smooth than cubic polynomial Bézier curve.

Bézier曲线是计算机辅助几何设计中的一类重要曲线，文献[1]介绍了三次Bézier曲线插值，文献[2]介绍了三次Bézier曲线的保凸插值，但难以解决一端曲率为0，另一端曲率比较大的插值问题。

On the other hand,the research of technology and development of product should truncate cycle, cut costs and increase production levels.

这样尖锐对立的两方面的要求，只有通过使用强大的计算机辅助分析设计技术和工具才能实现。

This thesis analyzes the types and art trait of solar-assisted heat pump water heater, the development trend of direct expansion solar-assisted heat pump water heater, makes a summary of these research results from six aspects. On the basis of these works and from the point of view of receiving optimum solar radiation , the thesis develops a novel design model of direct expansion solar-assisted heat pump water heater with a truncated cone collector/evaporator, theoretically analyzes the heat that the system can absorb, compares its ability with other two types of cylinder and flat plate ones, and calculates COP and EER with computer aids. The results show that a truncated cone direct expansion solar-assisted heat pump water heater can absorb not only more solar energy but heat energy in air. It takes on favorable thermal performance. Under the average day in February which is of the worst weather throughout the year in Kunming, the COP is about 4. 2, EER is about 2.9 . The heat absorbed by the system are more than those of the other systems. The system is very great in terms of saving

本文分析研究了太阳能热泵热水系统的分类及技术特点，直膨式太阳能热泵技术国内外发展趋势，从六个方面对直膨式太阳能热泵热水系统的研究进行了归纳总结；在此基础之上，从太阳辐射的最佳接收考虑，提出了集热器／蒸发器为圆台侧面的圆台型直膨式太阳能热泵热水器的设计模型，理论上分析了这种热水系统所接收的太阳辐射和得热量，并与圆柱型、平板型的直膨式太阳能热泵热水系统进行对比分析，通过计算机辅助模拟计算出：系统不但可以有效地吸收太阳能，还能有效地吸收空气中的热量，具有良好的热性能；在昆明，以2月为代表的冬季，其太阳辐照较低，系统的制热系数COP值也能达到4.2，效能比EER值为2.9；系统的得热量高出圆柱型、平板型的直膨式太阳能热泵热水系统，节能效果明显。

Reality includes machinery basis exercise during the model; mould disassembly , plotting; the benchwork training; the machine tool is handled; the computer-aid software is trained to wait for a project, the maximum has improved self machinery design relevance ability.

实训期间包括机械基础的练习；模具的拆卸，绘图；钳工的训练；机床操作；计算机辅助软件训练等项目，极大提高了自己的机械设计相关能力。

This paper describes the methods of computer aided modeling and numeral control machining to be used in design and manufacture of high precision solid casting dies,which contributes to the nationalization of the fan dynamic bladed wheel for a certain product.

论述在设计制造高精度的整体叶轮压铸模的过程中，采用的计算机辅助造型和数控加工的工艺方法，成功的实现了某产品叶轮制造的国产化。

The model definition language and the model manipulation language, which are suited for representing mechanical optimization models, are also studied. To choose the optimization methodic softwares, the characteristics of different programs have to be understood deeply, so it is needed to evaluate related programs.

机械优化设计模型是有前处理过程的复杂模型，模型的管理和存贮是计算机辅助建模的关键，为此，又研究了适合于描述机械优化模型和方便智能化处理的模型定义语言和模型操作语言，并建立了相应的模型库管理系统。

Nextly, introduces the designing of the virtual simulation experiment and real-time control experiment on the network laboratory from software and hardware.

其特色创新之处在于： 1采用了两套著名的辅助设计与测控软件，完美实现了两者在同一计算机环境下的软接口，使虚拟实验室的开发具有了比较高的起点，界面新颖，数据可靠、功能丰富。

Geometric methods developed herein to obversely and inversely calculate the parameters of rational Bézier circular arcs with degrees of three and four are simple, practical and have direct geometric meaning.

所给算法具有几何直观性、简单、实用，符合计算机辅助几何设计的要求。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了