例题反讲法的尝试

反讲法属于非传统例题讲解法，本文从反讲法的运用、题源和意义三个方面进行了详细的讨论使例题讲解丰富多彩，达到提高教学质量，传授知识，培养能力的目的。     

例题反讲法的尝试

例题反讲法的尝试孙直（江苏省连云港化工高等专科学校，连云港２２２００１）１例题反讲法的运用大凡在讲坛上耕耘多年的教师，都会积累一些讲解例题的经验．如例题正讲，就是先为学生理清思路，然后再接解题步骤求解；最后得出正确答案．又如为了拓宽学生的思维视野，一...     

基于水平集法的薄板加强筋分布优化理论研究

基于水平集方法,提出薄板加强筋分布的拓扑优化理论。采用Kirchhoff板单元,通过刚度等效,分别使用不同的抗弯刚度表征薄板与加强筋,继而通过水平集方法描述加强筋的布局并进行加强筋分布拓扑优化。以最小柔顺度为设计目标,进行了几种典型载荷下加筋板结构的加筋分布优化设计,通过与变密度方法（SIMP）结果以及现有文献设计结果进行对比,验证了本文提出的加强筋分布拓扑优化理论。结果显示,本文方法能够避免灰度单元,获得清晰的加强筋优化布局和尺寸。     

Lorentz force electrical impedance tomography using pulse compression technique

Lorentz force electrical impedance tomography(LFEIT) combines ultrasound stimulation and electromagnetic field detection with the goal of creating a high contrast and high resolution hybrid imaging modality. In this study, pulse compression working together with a linearly frequency modulated ultrasound pulse was investigated in LFEIT. Experiments were done on agar phantoms having the same level of electrical conductivity as soft biological tissues. The results showed that:(i) LFEIT using pulse compression could detect the location of the electrical conductivity variations precisely;(ii)LFEIT using pulse compression could get the same performance of detecting electrical conductivity variations as the traditional LFEIT using high voltage narrow pulse but reduce the peak stimulating power to the transducer by 25.5 dB;(iii)axial resolution of 1 mm could be obtained using modulation frequency bandwidth 2 MHz.     

城建大专结构力学课程的总体设想

城建大专结构力学课程的总体设想孙直（江苏连云港化工高等专科学校连云港２２２００１）结构力学是城建大专的一门技术基础课程，学时一般为９０ｈ，比同专业本科的学时数少２０～３０ｈ．目前；城建大专的结构力学还没有一个统一的教学大纲．如何根据专科层次的特点，从...     

Lorentz Force Electrical Impedance Detection Using Step Frequency Technique

Lorentz force electrical impedance tomography(LFEIT) inherits the merit of high resolution by ultrasound stimulation and the merit of high contrast through electromagnetic field detection. To reduce the instantaneous peak power of the stimulating signal to the transducer, the sinusoidal pulse and step-frequency technique is investigated in LFEIT. The theory of application of step-frequency technique in LFEIT is formulated with the direct demodulation method and the in-phase quadrature demodulation method. Compared with the in-phase quadrature demodulation method, the direct demodulation method has simple experimental setup but could only detect half of the range. Experiments carried out with copper foils confirmed that LFEIT using the step-frequency technique could detect the electrical conductivity variations precisely, which suggests an alternative method of realization of LFEIT.     

基于边界位移的复合材料力学参数无损反演方法

非均质材料参数识别在工程学、医学以及生物力学等众多领域具有重要意义.目前求解材料参数识别这类反问题主要采用优化方法,通常需要已知结构的全场位移信息,使含有位移的目标函数最小化,从而获得材料参数分布.然而在实际工程中,结构内部的位移较难测量且测量精度低.因此,本文拟提出一类仅利用边界位移就能进行非均质材料参数分布反演的方...     

基于移动可变形组件法(MMC)的运载火箭传力机架结构的轻量化设计

传力机架是运载火箭箭体与发动机连接的关键部件,负责将发动机推力载荷有效的传递至箭体,其结构的轻量化设计不仅可以保障火箭发动机的推重比、提高火箭的稳定性,还可以为我国未来可重复使用式火箭的研究提供一定的参考.本文在移动可变形组件(moving morphable component,MMC)的框架下,提出了一种解决传力机...