期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
Research on aiming methods for small sample size shooting tests of two-dimensional trajectory correction fuse
1
作者 Chen Liang Qiang Shen +4 位作者 Zilong Deng Hongyun Li Wenyang Pu Lingyun Tian Ziyang Lin 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期506-517,共12页
The longitudinal dispersion of the projectile in shooting tests of two-dimensional trajectory corrections fused with fixed canards is extremely large that it sometimes exceeds the correction ability of the correction ... The longitudinal dispersion of the projectile in shooting tests of two-dimensional trajectory corrections fused with fixed canards is extremely large that it sometimes exceeds the correction ability of the correction fuse actuator.The impact point easily deviates from the target,and thus the correction result cannot be readily evaluated.However,the cost of shooting tests is considerably high to conduct many tests for data collection.To address this issue,this study proposes an aiming method for shooting tests based on small sample size.The proposed method uses the Bootstrap method to expand the test data;repeatedly iterates and corrects the position of the simulated theoretical impact points through an improved compatibility test method;and dynamically adjusts the weight of the prior distribution of simulation results based on Kullback-Leibler divergence,which to some extent avoids the real data being"submerged"by the simulation data and achieves the fusion Bayesian estimation of the dispersion center.The experimental results show that when the simulation accuracy is sufficiently high,the proposed method yields a smaller mean-square deviation in estimating the dispersion center and higher shooting accuracy than those of the three comparison methods,which is more conducive to reflecting the effect of the control algorithm and facilitating test personnel to iterate their proposed structures and algorithms.;in addition,this study provides a knowledge base for further comprehensive studies in the future. 展开更多
关键词 Two-dimensional trajectory correction fuse Small sample size test Compatibility test KL divergence Fusion bayesian estimation
下载PDF
AFFECTION OF SIZE-DISTRIBUTION TESTING APPARATUS ON DETERMINED RESULTS
2
作者 李冷 曾宪滨 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1994年第1期155-163,共9页
This paper comprehensively analyzes every factor affecting the medium sedimentating measurement of poivder size distribution, and based on this, selects the optimum condition. Three size testing apparatus are used for... This paper comprehensively analyzes every factor affecting the medium sedimentating measurement of poivder size distribution, and based on this, selects the optimum condition. Three size testing apparatus are used for a-Al2O3 powder measurements and the measured results are analyzed and compared with each other by unary linear regression method. 展开更多
关键词 POWDER size distribution size testing
下载PDF
Effect of drying environment on engineering properties of an expansive soil and its microstructure 被引量:12
3
作者 KONG Ling-wei WANG Min +1 位作者 GUO Ai-guo WANG Yong 《Journal of Mountain Science》 SCIE CSCD 2017年第6期1194-1201,共8页
This paper investigates the effect of drying environment, i.e. temperature and relative humidity, on the engineering properties and microscopic pore size distribution of an expansive soil. The shrinkage tests under di... This paper investigates the effect of drying environment, i.e. temperature and relative humidity, on the engineering properties and microscopic pore size distribution of an expansive soil. The shrinkage tests under different drying temperatures and relative humidity are carried out in a constant climate chamber. Then, the undisturbed samples, prepared in different drying environment, are used for the triaxial tests and mercury intrusion tests. It is found that the drying environment has noticeable influence on the engineering properties of expansive soils and it can be characterized by the drying rate. The linear shrinkage and strength increase with the decrease of the drying rate. The non-uniform deformation tends to happen in the high drying rate, which subsequently furthers the development of cracks. In addition, during the drying process, the variation of pores mainly focuses on the inter-aggregate pores and inter-particle pores. The lower drying rate leads to larger variation of pore size distribution. 展开更多
关键词 Expansive soils Drying environment Shrinkage Strength Pore size distribution Triaxial test
原文传递
Small Class Size Boosts Test Scores Later
4
作者 王兴法 《当代外语研究》 2001年第6期5-6,共2页
Smaller class sizes in early grades translated into students scoring higher on math tests in later grades in Tennessee’s experiment to see if smaller classes improved education, a study said on Friday. 低年级的小型... Smaller class sizes in early grades translated into students scoring higher on math tests in later grades in Tennessee’s experiment to see if smaller classes improved education, a study said on Friday. 低年级的小型班级能够使学生在高年级时获得数学测试的高分。田纳西州的一项旨在了解小型班级是否能够改进教育的实验得出如此结论。一项研究周五如是说。 展开更多
关键词 田纳西州 Small Class Size Boosts test Scores Later
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部