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11.
从现代科学的角度揭示和分析安全的本质含义。安全本质应该包括:一是预知、预测、分析危险;二是限制、控制、消除危险。当人们讲到危险的时候,实际上是在研究危险。安全的含义随着人类社会经济的发展而变化。当代事故的灾害性、社会性、突发性是由于事故过程的技术密集性和物质高能性引起的。本文从现代科学技术和社会经济发展的基本经济规律出发,分析当代事故的本质特性。 相似文献
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Liang Xu Xuhai Li Yihang Cui Zhiguo Li Qingyun Chen Chuanmin Meng Haibing Zhang Jianbo Hu Qiang Wu 《Ceramics International》2021,47(15):21008-21012
Ti3SiC2 is of interest due to its unique dual nature reminiscent of both brittle ceramics and ductile metals at ambient conditions. In this work, plate-impact experiments have been performed to study the dynamic behavior of Ti3SiC2 under shock compression up to 112 GPa by using laser velocity interferometer and electric pin techniques. Hugoniot elastic limits (HEL), spall strength, and Hugoniot equations of state have been obtained based on measured particle velocity profiles and shock wave velocities. The ratio of spall strength to HEL for Ti3SiC2 is larger than brittle ceramics but smaller than metals. This result indicates that the dual nature of Ti3SiC2 remains at least up to 10 GPa. On the other hand, the linearity of the Hugoniot equation of state, , suggests that the initial structure of Ti3SiC2 should be stable up to 112 GPa, in contrast to the result reported by Jordan et al. [J. Appl. Phys., 93 (2003) 9639]. 相似文献
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Dissolved oxygen in the steel at the terminal of the converter smelting process is the main cause for the formation of oxide inclusions, and the high terminal oxygen content worsens the steel cleanness. However, post stirring in a combined blowing converter can promote the carbon-oxygen reaction in the liquid steel and reduce the dissolved oxygen content at the terminal of the converter smelting process. Thus, the mathematical model of deoxidization in the post stirring process was obtained, and the rationa... 相似文献
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The effects of insoluble eutectic Si particles on the growth of anodic oxide films on ZL114A aluminum alloy substrates were in-vestigated by optical microscopy (OM) and scanning electron microscopy (SE... 相似文献
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金属基复合材料力学性能分散性影响其性能评价和广泛应用.本文研究了测量方法和组织缺陷对SiCw/Al复合材料力学性能统计分布规律的影响.结果表明,复合材料的弹性模量、强度和延伸率等性能均存在分散性,高性能数据出现频率最高,向低的性能值分散.弹性模量分散性受测量方法影响很大,直线段扩大法可以减小性能分散范围.强度和延伸率性能高的试样中发现夹铝区或未浸渗区等缺陷的概率远低于低性能试样,微观缺陷是造成强度和延伸率向低值方向分散的主要原因.为此减少组织缺陷并合理选择实验方法对复合材料的性能评价和应用是必要的. 相似文献
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Multimedia Systems - Camouflage effect evaluation and examination is an important procedure in digital camouflage pattern design as it is helpful in improving the objectivity and effectiveness... 相似文献
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Cui‐Zhen Yao 《Asian journal of control》2013,15(5):1531-1537
This article considers stabilization of a one‐dimensional Schrödinger equation with variable coefficient and boundary observation which suffers from an arbitrary given time delay. We design an observer and predictor to stabilize the system. The state is estimated in the time span where the observation is available, and also predicted in the time interval where the observation is not available. It is shown that the estimated state feedback stabilizes the system exponentially. A numerical simulation is presented to illustrate the effect of the stabilizing controller. 相似文献
20.
Afify M. Cui X. Gao Y. 《IEEE transactions on audio, speech, and language processing》2009,17(7):1325-1334
We present a stochastic mapping technique for robust speech recognition that uses stereo data. The idea is based on constructing a Gaussian mixture model for the joint distribution of the clean and noisy features and using this distribution to predict the clean speech during testing. The proposed mapping is called stereo-based stochastic mapping (SSM). Two different estimators are considered. One is iterative and is based on the maximum a posteriori (MAP) criterion while the other uses the minimum mean square error (MMSE) criterion. The resulting estimators are effectively a mixture of linear transforms weighted by component posteriors, and the parameters of the linear transformations are derived from the joint distribution. Compared to the uncompensated result, the proposed method results in 45% relative improvement in word error rate (WER) for digit recognition in the car. In the same setting, SSM outperforms SPLICE and gives similar results to MMSE compensation of Huang A 66% relative improvement in word error rate (WER) is observed when applied in conjunction with multistyle training (MST) for large vocabulary English speech recognition in a real environment. Also, the combination of the proposed mapping with CMLLR leads to about 38% relative improvement in performance compared to CMLLR alone for real field data. 相似文献