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1.
为了研究人机结合效率的高低,通过对操作复杂程度不同的器材进行实验分析:在同一教练员的组织下,不同层次的学习对象的人机结合效率;在不同教练员的组织下,同一层次对象的人机结合效率。通过实验研究表明:学习对象层次或教练员不同,其人机结合效率都存在着明显差异。同时探讨了一些教学方面的对策。  相似文献   

2.
本文研究用8098单片机对密闭大贮槽的贮液容量进行自动检测的应用系统,解决了把贮槽液位测量传感器输出的电流信号直接转换成贮液重量进行显示,从而使显示直观、清晰.  相似文献   

3.
Based on the method of successive substitutions, an integral equation is derived in which multiple reflections are explicitly identified. This equation is used provide simple methods of estimating the local effective radiation of two-dimensional and three-dimensional systems of surfaces, with due regard for the anisotropy of their optical properties. A cylindrical cavity confined by the surface of a right circular cylinder with a side pyrometric hole is treated as an example. The results obtained by the suggested method are compared with the data of direct solution of an integral equation for the two-dimensional problem.  相似文献   

4.
This paper discusses whar are the proper criteria for decision-making in planning and design. A parable introduces three principles by which to justify decisions: the principle of indifference or chance, the principle of absolute truth and the principle of idoneity, where the idoneus is ‘that which is proper to, and conforms with, the ends and intentions’.  相似文献   

5.
Based on analyses for the electromagnetic pressure on the melt and the heat induced in the melt, the ratio of heat to pressure Q0/Pm is defined, to give the relationship between Qo/Pm and the thickness a, the electromagnetic parameter (μγ) of the melt and the electric current frequency/under the electromagnetic confinement and shaping process. If Qo/Pm is large, any adjustment to the melt shape will easily cause a variation of the temperature in the melt. In this situation, there appears to be a more sensitive interaction between the shape and the temperature field and a more narrow adjustment range for the process. Experiments on thin plate samples with a cross-section of 6 mm × 18 mm are done with two kinds of induction coils. The results show that when a coil with a trumpet inside wall is used and the positions of the melt top and the S/L interface are properly selected, the melt periphery is nearly vertical and the temperature gradient ahead of the S/L interface is high. Under these conditions, a more stable and wider coupling between the shape and the temperature field is continuously maintained and samples with a smooth surface and unidirectional crystals are successfully obtained.  相似文献   

6.
为了研究采煤机截割过程中的动力学特性及其对截割载荷的影响,采用含滚筒振动量的锋利截齿截割阻力模型描述滚筒截割载荷,采用含间隙齿轮啮合模型描述行走轮驱动载荷,采用库伦摩擦模型描述平滑靴摩擦载荷,建立了采煤机整机五自由度动力学模型,利用ode45对模型求解.结果表明:当煤岩硬度f=3,行走速度为3m/min时,采煤机右摇臂振动幅值约为0.8×10~(-4)rad,左摇臂振动幅值约为0.4×10~(-5)rad;机身振动速度在-1.4~+1.4mm/s间波动,右、左摇臂的振动角速度分别在-1×10~(-3)~+1×10~(-3) rad/s和-4.5×10~(-4)~+4.5×10~(-4) rad/s间波动;通过对比考虑滚筒振动和未考虑滚筒振动时的截割载荷,表明滚筒的振动有利于对煤岩的截割;对右侧摇臂的振动量进行了实验测量,其大小及波动范围与仿真值较为接近,说明采煤机的动力学模型具有一定的准确性.  相似文献   

7.
制冷剂高压能的利用对改善制冷系统运行有重要意义。基于场协同理论,提出了一种利用制冷剂在蒸发管内进行喷射的新型制冷系统,理论上分析了协同角随毛细管管径和喷射孔直径的变化规律,并进行了相关的可视化实验。理论分析结果表明:协同角随着喷射孔直径的增大而增大;随着毛细管管径的减小而减小,但是随之减小的速率降低。实验结果表明:和传统的毛细管节流制冷系统相比,开孔实验的制冷剂的充注量减少70%以上,COP提高了9%,系统达到稳定的时间减少了70%。  相似文献   

8.
作为瞬态高速激光测速仪测量过程中的合作目标,光栅表面的技术状态决定了激光多普勒信号的质量。特别是在弹体高速冲击条件下,极易造成光栅的内部结构发生损坏,导致反射光无法入射至探测器敏感部。因此,本文采用LS-DYNA仿真软件对砧体结构与光栅的连接处展开分析,并获取表面处的应力应变分布,从而为光栅结构的布置方式提供参考依据。其次,为了达到对光路修正的目的,通过对入射镜组的选型与设计,确定出了最优偏摆角的范围为5.2°。这不仅解决了光束偏摆造成输出结果误差较大的问题,同时也为光栅结构的优化设计提供参考依据。  相似文献   

9.
Based on analyses for the electromagnetic pressure on the melt and the heat induced in the melt, the ratio of heat to pressure Q0/Pm is defined, to give the relationship between Q0/Pm and the thickness a, the electromagnetic parameter (μγ) of the melt and the electric current frequency f under the electromagnetic confinement and shaping process. If Q0/Pm is large, any adjustment to the melt shape will easily cause a variation of the temperature in the melt. In this situation, there appears to be a more sensitive interaction between the shape and the temperature field and a more narrow adjustment range for the process. Experiments on thin plate samples with a cross-section of 6 mm×18 mm are done with two kinds of induction coils. The results show that when a coil with a trumpet inside wall is used and the positions of the melt top and the S/L interface are properly selected, the melt periphery is nearly vertical and the temperature gradient ahead of the S/L interface is high. Under these conditions, a more stable and wider coupling between the shape and the temperature field is continuously maintained and samples with a smooth surface and unidirectional crystals are successfully obtained.  相似文献   

10.
以家具的风格、造型形态、装饰、色彩、材料、功能、价格定位等方面作为主要的评价项目,针对消费者和设计师分别设计了感性意象的调查问卷并进行问卷调查。通过对调查数据的研究分析,获得消费者和设计师在家具感性意象上的共同点和差异性,并构建了消费者和设计师的家具产品感性意象的偏好模型,模型可用于指导家具方案设计,避免家具设计的盲目性,从而降低了设计风险,提高家具方案设计的成功性。  相似文献   

11.
This paper presents model asymmetries in the topography of the human cornea arising from linear gravitational distributions of the intraocular pressure. Equations for the corneal radius of curvature were used to provide an indication of the gravitational sag of the cornea when the head is in an upright position. In such case, corneal astigmatism is found along the optic axis of the eye. Ray paths inclined at a particular angle to the optic axis produce images (spot diagrams) which show a significant reduction in corneal astigmatism.  相似文献   

12.
论知觉对象与背景的关系   总被引:3,自引:2,他引:1  
杨君顺  程远 《包装工程》2006,27(1):159-161
通过将"万绿丛中一点红"中的哲学原理在广告的创意、制作中的运用得到的经验,阐述了这样的原理:知觉对象与背景是通过对比与协调达到和谐统一的,它们通过色彩与造型的差异性和互补性,产生奇特的视觉效果,给人以鲜明的印象和强大的视觉冲击力,从而达到吸引消费者的目的.这在广告学中有着至关重要的作用,也是众多广告设计中都遵守的原则之一.  相似文献   

13.
The dependence of the coefficient of concentration jump on the coefficient of vaporization for a diluted binary mixture, when the concentrations of the components are significantly different, has been investigated. The analytical expression of the concentration jump for the case where the frequency of collisions of molecules is in proportion to their velocity has been obtained. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 2, pp. 121–126, March–April, 2007.  相似文献   

14.
包装纸盒盒型参数化设计应用程序的开发与实现   总被引:2,自引:1,他引:1  
高佳宏  朱梅玲  王琳 《包装工程》2006,27(1):135-136,139
为了提高包装纸盒盒型的设计效率,在Pro/E应用软件的基础上,利用其自带的二次开发工具Pro/TOOLKIT,采用对话框资源文件设计技术、程序源文件设计技术和程序注册运行技术,完成了包装纸盒盒型参数化设计应用程序的开发,实现了包装纸盒盒型的参数化设计.  相似文献   

15.
New sheath structures near the ion engine of the spacecraft are investigated by numerical calculation. We show the double sheath potential, the space charge density and the double electric field by the dust grains and secondary electrons. Temporal evolution of the grain charge near the ion engine is simulated by the conservation law of the electric charge-current equation. It turns out that the control of the plasma sheath near the ion engine of the spacecraft is possible.  相似文献   

16.
The paper presents influence of the rotor blade tip shape of an axial fan on the emitted noise and on its aerodynamic characteristic. Appropriate measurements were first performed on the integral level of the same rotor with the two blade tip shapes: blade tip configuration A where the blade tip has the form of the prolonged basic blade, and configuration B with the winglet where the tip was slightly pushed towards the suction side of the blade. Moreover results of local pressure and sound pressure measurements in the area of the air gap made possible detailed analysis of the avarage pressure distribution and its time variance. The results showed strong dependence of the blade tip design on the emitted noise distribution, whereas changes of the aerodynamic characteristic with both tip designs were hardly noticed. The correlation between the emitted sound power level of the fan and the air pressure variance enabled to locate mechanism and origin of the noise generation in the zone between two consecutive rotor blades.  相似文献   

17.
对盒体零件的冲孔工艺方案进行了分析,介绍了各种冲孔工艺方案的优缺点,从而确定了利用凸轮机构,实现了该零件的径向冲孔。介绍了该模具结构及工作过程,给出了零件的工艺计算方法,提出了模具的设计方法,为解决同类零件的冲孔提供了参考。  相似文献   

18.
New sheath structures near the ion engine of the spacecraft are investigated by numerical calculation. We show the double sheath potential, the space charge density and the double electric field by the dust grains and secondary electrons. Temporal evolution of the grain charge near the ion engine is simulated by the conservation law of the electric charge–current equation. It turns out that the control of the plasma sheath near the ion engine of the spacecraft is possible.  相似文献   

19.
物品包装临界跌落高度与缓冲衬垫特性参数关系初探   总被引:1,自引:1,他引:0  
运用经典的加速度损坏边界和新提出的位移损坏边界理论,研究了线性包装系统临界跌落高度与缓冲衬垫特性参数(缓冲初垫刚度、最大可压缩量)间的关系,并给出了数值解,为包装动力学理论在工程缓冲设计中的简化应用提供了一种途径和方法。  相似文献   

20.
The results of an investigation of different types of tungsten lamps in order to estimate the components of the error budget of spectrum-pyrometer apparatus are presented. Quantitative relations are considered and the results of experimental research, which enable systematic methods to be developed for eliminating the influence of polarization of the radiation of the lamps in standard radiation thermometry, are analyzed.Translated from Izmeritelnaya Tekhnika, No. 9, pp. 42–45, September, 2004.  相似文献   

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