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冯叔瑜院士,1948年毕业于上海交通大学土木工程系,1951年赴前苏联留学,获技术科学副博士学位。回国后到铁道部科学研究院工作,长期从事工程爆破技术的研究与应用,是工程爆破专家。历任中国铁道工程学会爆破专业委员会主任,中国力学学会工程爆破专业委员会主任,中国民爆器材学会理事,中国工程爆破协会副理事长。1995年作为工程爆破学科的奠基人之一当选中国工程院院士。 相似文献
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Piezoelectric resonators are widely used in frequency reference devices, mass sensors, resonant sensors(such as gyros and accelerometers), etc. Piezoelectric resonators usually work in a special resonant mode. Obtaining working resonant mode with high quality is key to improve the performance of piezoelectric resonators. In this paper, the resonance characteristics of a rectangular lead zirconium titanate(PZT) piezoelectric resonator are studied. On the basis of the field-programmable gate array(FPGA) embedded system, direct digital synthesizer(DDS) and automatic gain controller(AGC) are used to generate the driving signals with precisely adjustable frequency and amplitude. The driving signals are used to excite the piezoelectric resonator to the working vibration mode. The influence of the connection of driving electrodes and voltage amplitude on the vibration of the resonator is studied. The quality factor and vibration linearity of the resonator are studied with various driving methods mentioned in this paper. The resonator reaches resonant mode at 330 kHz by different driving methods.The relationship between resonant amplitude and driving signal amplitude is linear. The quality factor reaches over 150 by different driving methods. The results provide a theoretical reference for the efficient excitation of the piezoelectric resonator. 相似文献
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王家大院古香古色别有一番风味
在浩如烟海的中国传统民居建筑中,灵石王家大院被人们称誉为“天上取样人间造,雕艺精湛世上绝”,以其规模宏大,气势壮观,装饰精微,构思巧妙,散发出华夏民族传统文化的精神、气质、神韵,这里将是我们的目的地.
此行是东风悦达起亚的车队自驾游.早上,按领队约定的时间,我们到达了指定的4S店集合,看到清一色的东风悦达起亚车不禁让我们找到了归属感,还有一些些小兴奋.领队很热心,全副武装早已准备到位,给每一辆到来的汽车发车标,车号,车贴,还有对讲机.等所有车辆都到位,领队宣讲完注意事项和路线后,我们一行10多辆车就浩浩荡荡出发了.我们的行程是上午参观灵石王家大院,下午泡温泉. 相似文献
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就滨州市土壤的情况,进行了一系列的物化性能测试,以取得工程应用,最终掌握了滨州市土壤的基本参数,并对滨州市的土壤进行了科学分类. 相似文献
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本文对叠层梁的弯曲内力和应力进行了试验分析.结果表明,在一般受力情况下,上、下梁间同截面处内力不同,并分析了上、下梁内力不同的原因. 相似文献
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