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排序方式: 共有602条查询结果,搜索用时 125 毫秒
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夏洪瑞 《勘探地球物理进展》2008,31(2):117-121
Morlet小波被广泛应用于地震资料属性提取中的主要原因是Morlet小波为复小波且对高频噪声有压制作用。分析了Morlet小波的滤波机理及实现过程,指出由于Morlet小波在频域呈钟形状,决定了它不是理想滤波器。应用不含噪模型和信噪共存模型进行实例测试的结果表明,Morlet小波不能消除信噪共存频带内的噪声,并且在去噪过程中对有效波有不同程度的损害。为此指出应用Morlet小波进行地震资料属性提取不是最佳选择。 相似文献
34.
辅助加热PCVD—TiN薄膜的性能及结构分析 总被引:2,自引:0,他引:2
研究了反应气体对辅助加热PCVD-TiN薄膜制备的影响。结果表明,提高反应气体中TiCl4薄膜内的氯含本不变。 相似文献
35.
Ben Williams Xiaowei Wang Hongrui Ma Roger Cracknell David Richardson Stan Wallace 《Combustion and Flame》2010,157(10):1866-1878
A study of in-cylinder fuel-air mixing distributions in a firing gasoline-direct-injection engine is reported using planar laser-induced fluorescence (PLIF) imaging. A multi-component fuel synthesised from three pairs of components chosen to simulate light, medium and heavy fractions was seeded with one of three tracers, each chosen to co-evaporate with and thus follow one of the fractions, in order to account for differential volatility of such components in typical gasoline fuels. In order to make quantitative measurements of fuel-air ratio from PLIF images, initial calibration was by recording PLIF images of homogeneous fuel-air mixtures under similar conditions of in-cylinder temperature and pressure using a re-circulation loop and a motored engine. This calibration method was found to be affected by two significant factors. Firstly, calibration was affected by variation of signal collection efficiency arising from build-up of absorbing deposits on the windows during firing cycles, which are not present under motored conditions. Secondly, the effects of residual exhaust gas present in the firing engine were not accounted for using a calibration loop with a motored engine.In order to account for these factors a novel method of PLIF calibration is presented whereby ‘bookend’ calibration measurements for each tracer separately are performed under firing conditions, utilising injection into a large upstream heated plenum to promote the formation of homogeneous in-cylinder mixtures. These calibration datasets contain sufficient information to not only characterise the quantum efficiency of each tracer during a typical engine cycle, but also monitor imaging efficiency, and, importantly, account for the impact of exhaust gas residuals (EGR). By use of this method EGR is identified as a significant factor in quantitative PLIF for fuel mixing diagnostics in firing engines.The effects of cyclic variation in fuel concentration on burn rate are analysed for different fuel injection strategies. Finally, mixture distributions for late injection obtained using quantitative PLIF are compared to predictions of computational fluid dynamics calculations. 相似文献
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高速钢工件表面物理化学气相沉积TiN 总被引:9,自引:0,他引:9
介绍了等离子化学气相沉积氮化钛技术在高速钢刀具和飞机用高速钢精密轴承上的应用,经PCVD-TiN处理的高速钢刀具可以提高其表面强度,降低摩擦系数,从而提高其使用寿命,处理过的高速钢轴承精度高,具有抗高温氧化和抗热震性能,满足了使用要求。 相似文献
38.
剩余动校正量的拾取与消除 总被引:10,自引:2,他引:8
为了克服剩余动校正量对降低地率的影响,本文在叠加记录上利用禹前向后预测建立模型道,按最大相似系数准则示诹剩余动校正量,然后采用Buterworth滤波器进行滤波插值一完成高精度动态拉伸校正,从而消除剩余校正的影响,保持了地震记录的原有分辩率,并使叠另过程中产生的噪声得到衰减。理论模型试算与实际应用表明,该方法的处理效果良好。 相似文献
39.
Zhen Li Hongrui Jia Jintao Lu Yinfei Li Zhigang Liang Jing Wei Linghang Wang 《Journal of the American Ceramic Society》2023,106(8):4732-4739
High-performance piezoelectric materials are essential in many piezoelectric devices. However, the composition of piezoelectric materials usually has a great influence on their performance. In this work, xBi(Mg1/2Ti1/2)O3–yPbZrO3–zPbTiO3 (xBMT–yPZ–zPT; 0.2 ≤ x ≤ 0.4, 0.25 ≤ y ≤ 0.4, and 0.35 ≤ z ≤ 0.4) ternary ceramics with different compositions were synthesized and it was found that the strain response was not sensitive to the composition. The crystal structure, strain response, ferroelectric properties, and temperature stability of xBMT–yPZ–zPT ceramics were investigated in detail. X-ray diffraction patterns show that all the as-prepared xBMT–yPZ–zPT ceramics with x = 0.2, 0.3, 0.4, and 0.5 possess a perovskite structure. Under an external electric field of 6 kV mm−1, the strain values of xBMT–yPZ–zPT ternary ceramics with x = 0.2, 0.3, 0.4, and 0.5 were 0.30%, 0.31%, 0.30%, and 0.27%, respectively. In addition, the strain hysteresis of these ternary ceramics is also almost the same and low. These merits make xBMT–yPZ–zPT piezoelectric ceramics have broad application prospects in the field of commercial actuators. 相似文献
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