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81.
We present results of finite-element analysis of stressed state in a percussive-rotary drilling bit fitted with hardmetal
inserts during its contact interaction with rock, allowing for brazing-induced stresses. The most likely fracture zones in
inserts have been identified. Based on the proposed criterion for fatigue strength of structurally inhomogeneous materials,
the binder composition of the inserts has been optimized for the longest service life. It is demonstrated that the formation
of a gradient structure in a hardmetal, whereby the material preserves its initial mechanical properties in the main volume
but has an increased ultimate tensile strength in zones where tensile stresses are involved, results in a longer service life
of the hardmetal products and a noticeably diminished dependence of their cyclic strength on the scale factor.
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Translated from Problemy Prochnosti, No. 2, pp. 15–31, March–April, 2007. 相似文献
82.
介绍了一种高性能光波导脉冲单选器的研制.该模块由高速前放电路,数字逻辑电路,强度调制器驱动电路,自动增益控制电路,以及强度调制器组成.模块能够从锁模激光器的连续脉冲中选出一个单脉冲,并保证消光比≥46 dB,插入损耗≤7 dB.文章重点介绍了系统的设计方案、工作原理、参数设计,以及特性曲线分析,并且对测试得到的主要参数进行了总结分析. 相似文献
83.
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85.
基于数学形态学的重叠昆虫图像分离的研究 总被引:6,自引:0,他引:6
牟少敏 《计算机工程与应用》2003,39(18):219-220
在实际的昆虫图像处理中,经常会碰到重叠现象。即多个昆虫聚集在一起,这给后续昆虫自动计数的结果的准确性产生一定的影响。因此需要对其进行有效的分离。论文以白粉虱图像为例,对其二值化后的图像,利用数学形态学方法中的腐蚀操作,达到将重叠昆虫有效分离的目的。为下一步昆虫图像的自动计数打下了良好的基础。文中主要讨论了算法的基本思想,并给出了实验结果。 相似文献
86.
一种基于模式分析的防止遗传算法过早收敛的方法 总被引:1,自引:0,他引:1
本文提出一种遗传算法中模式的表示方法和个体间最大共有模式的获取方法,并以此为基础提出了基于模式分析的种群插入策略来解决遗传算法过早收敛问题.通过与其他种群插入算法的对比证明该
方法的有效性.给出了采用该种群插入策略的遗传算法的收敛性定理及其证明. 相似文献
87.
Abstract: A digital shearographic (DS) technique is a tool well‐suited for precision strain measurement and is a non‐destructive testing technology. But the fringe patterns of DS have not so high sensitivity due to the limitation of CCD camera resolution. Therefore a phase‐shifting technique is incorporated into DS and demonstrated to yield fringe patterns with good quality. The main purpose of this study is to set‐up a measuring system of digital phase‐shifting shearography (DPSS) to measure slope of the out‐of‐plane deflection of sandwich plate with a fully potted insert. The present system includes piezoelectric transducer, servo controller, Michelson shearing mechanism, image processing system and loading system. The four‐step phase shifting method is used to obtain phase map and then the phase expansion is proceeded by Macy algorithm to obtain the slope of the out‐of‐plane deflection of honeycomb sandwich plate with insert/potting material. Finally, comparing the slope of the out‐of‐plane deflection of DPSS with that of DS shows 2 to 7% difference of slope of deflection exhibiting. 相似文献
88.
Purpose: Soluble ocular inserts of ciprofloxacin hydrochloride were prepared with the aim of achieving once a day administration. Design: Drug reservoir was prepared using natural hydrophilic polymer viz. gelatin while rate-controlling membrane was prepared using hydrophobic ethyl cellulose. Ocular inserts were evaluated for their physicochemical parameters like thickness, weight uniformity, drug content, percent moisture loss, and percent moisture absorption. The in vitro drug release studies were carried out using Bi-chambered donar receiver compartment model. Since targeted prolong release was observed in formulation CF2 and CF5, these formulations were further subjected to in vivo drug release study using rabbits as an animal model. In vitro drug release kinetic data was treated according to Zero, First, and Higuchi kinetics to access the mechanism of drug release. Results: Correlation between in vitro and in vivo drug release was found to be strong revealing the efficacy of the formulation. Conclusion: Formulation CF5 has achieved target of present study such as increase residence time, prolong drug release, reduction in frequency of administration, and, thus may improve the patient compliance. 相似文献
89.
范龙江 《江汉石油职工大学学报》2005,18(2):24-26
江汉油区盐间非砂岩油藏具有较大的增产潜力,但产量递减快,容易导致油井近井地带碳酸盐结垢。为了提高增产效果,必须认识分析盐间非砂岩酸化机理,对盐间非砂岩油层酸化工艺、施工工艺进行改进。 相似文献
90.