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Secure and efficient anonymous proxy signature scheme in the random oracle model

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The Journal of China Universities of Posts and Telecommunications 2013年第4期20卷 87-92页

作者： ZHANG De-dong MA Zhao-feng NIU Xin-xin li guo-you Information Security Center Beijing University of Posts and Telecommunications Institute of Computing Technology China Academy of Railway Sciences

Anonymous proxy signature scheme can provide the privacy protection for the proxy signer. Recently, Yu et al. proposed an anonymous proxy signature, which can be viewed as the organic combination of proxy signature and ring signature. However, the efficiency is low. In this paper, we propose an efficient and secure proxy signature with the properties of anonymity and traceability, and it is provably secure in the random oracle model. Compared with Yu et al.＇s scheme, the scheme has higher efficiency.

关键词： anonymous proxy signature bilinear pairings random oracle model

Optimization of Fermentation Medium for Epothilones Production with Sequential Statistical Approach

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Chemical Research in Chinese Universities 2010年第1期26卷 86-91页

作者： MENG Fan-xin li you-xin guo Wei-liang LU Jia-hui DU lin-na TENG li-rong College of life Science Jilin University Changchun 130012 P. R. China

A sequential statistical approach was applied to optimizing the fermentation medium of epothilones（Epos） production by means of a mutant which was obtained by treating polyangium cellulosum ATCC 15384 with nitrite and ultraviolet. The effects of different carbon sources and nitrogen sources on the fermentation medium were tested, and the suitable ones were selected. Then a uniform design was employed to design the experiments. A linear model was developed for identifying the significant components in fermentation medium, while a third degree polynomial model was used for studying the relationship between the concentration of the components in fermentation medium and the yield of Epos（YEPs）. A pattern search method was used for searching the optimum fermentation medium in the test space, which was as follows（g/L）： potassium nitrate 8.00, soybean peptone 17.60, potassium hydrogen phos- phate 1.00, beef extraction 6.46, yeast extraction 1.00, calcium chloride 0.25, sodium chloride 1.00 and ferric chloride 0.02. The optimum fermentation medium was expected to result in a yield of Epos（YEPs） of 2.48 mg/L. The validation experiments with the optimum medium were performed in triplicate and the average yield of Epos was 2.45 mg/L which was 7.78 times higher than that of Epos prepared without optimization.

关键词： Statistical approach Epothilones Uniform design Optimization of fermentation medium

Vertical Short Crack Initiation in Medium Carbon Bainitic Steel Under Mild Tractive Rolling Contact

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Journal of Iron and Steel Research International 2008年第3期15卷 37-41页

作者： DOU Peng SUO Shuang-fu BAI Bing-zhe YANG Zhi-gang li you-guo Department of Precision Instruments and Mechanology Tsinghua University Beijing 100084 China Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

To improve the current grinding procedure of the back-up roll of CVC hot rolling mills so that the back-up roll service life can be extended, the crack initiation and propagation behavior of medium carbon bainitic back-up roll steel was investigated, a kind of asperity-scale, surface originated vertical short cracks occurred at 5 × 10^2 -1 × 10^4 cycles. Theoretical analysis indicated that the maximum tensile stress occurring at the back edge of the contact of asperities keeps at above 1 347. 97 MPa, and ratcheting and cyclic plastic deformation take place at such sites within 1 × 10^4 cycles. The early initiation of the vertical short cracks is caused by the asperity contact. According to the crack initiation mechanism, short crack behavior and preventive grinding strategy, steel consumption can be reduced considerably by decreasing the surface roughness and removing the asperity influenced surface thin layer at about 70%-80% of the surface distress life.

关键词： rolling contact fatigue medium carbon bainitie steel vertical short crack asperity rateheting

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中碳贝氏体钢的室温单轴循环变形行为研究

工程力学 2007年第4期24卷 173-177,167页

作者：康国政李友国西南交通大学应用力学与工程系成都610031 清华大学材料科学与工程系北京100084

为了了解中碳贝氏体钢支承辊的接触疲劳失效机制,对中碳贝氏体钢材料在室温单轴循环加载下的应变循环特性和棘轮行为进行了实验研究。讨论了材料的循环软/硬化特性及其对单轴棘轮行为的影响,同时揭示了该材料棘轮行为的平均应力、应力... 详细信息

为了了解中碳贝氏体钢支承辊的接触疲劳失效机制,对中碳贝氏体钢材料在室温单轴循环加载下的应变循环特性和棘轮行为进行了实验研究。讨论了材料的循环软/硬化特性及其对单轴棘轮行为的影响,同时揭示了该材料棘轮行为的平均应力、应力幅值及其加载历史的依赖性。实验研究表明:材料的循环软/硬化特性具有明显的应变幅值依赖性,进而导致材料在不同的应力水平下出现不同的棘轮行为。研究得到了一些有助于该类材料循环变形行为本构描述的结论。

关键词：贝氏体钢棘轮行为循环塑性单轴加载室温

Research on Farmers' Response to Microeconomic Policies and Its Impact on Land Degradation in Zhaodong Heilongjiang Province

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Journal of Northeast Agricultural University(English Edition) 2005年第2期12卷 182-185页

作者： JIA li li you-hua guo Dong-qing College of Economics and Management Northeast Agricultural University Harbin Heilongjiang 150030 PRC

The livelihoods of farmers are responding to the mioroeconomic policies and result in many changes in the landuse pattern and landscape, and the farmer＇s attitude to the natural resources conservation, specifically in the land degradation. In order to find the relationship between the farmers＇ response to the microeeonomic policies and land degradation, the authors surveyed 120 household in three villages in the black soil zone in Heilongjiang Province. Based on the feedback of the questionnaires, the authors established a model to analyze the impact. The results demonstrated that land degradation was impacted by farmers behaviors in the process of the adjustment of agricultural structures in the city of Zhaodong. And the main factors acted on the land degradation were the agricultural labour education level, the transfer of the labour from agricultural production, the price of the agricultural production materials, and the land scale management. The authors put forward some suggestions for sustainable agriculture based on the analysis on the topic.

关键词： microeconomic policy farm household land degradation Heilongjiang Province

论陕甘宁边区时期党的民族政策的执政资源意义

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贵州民族研究 2008年第1期28卷 163-167页

作者：厉有国信阳师范学院河南信阳464000

陕甘宁边区时期中国共产党局部执政,党的民族政策对于党团结少数民族,发展民族经济,巩固边区,扩大政治影响,开发执政资源发挥了重要作用,它开发了党的民族民心资源、党的民族制度资源和党的民族人才资源。

关键词：陕甘宁边区民族政策执政资源

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发展高技术产业的紧迫性和“捷径”

科学学研究 1989年第1期7卷 49-58,67页

作者：李国友中国社会科学院美国研究所

本文着重从相对发展差距,国际竞争格局,优、劣势比较和转化着眼,探讨高技术产业的发展战略。强调要“机制挂帅”,建立适宜的环境和支撑结构;要面向世界市场,提高和发达国家的结合层次,扩展和新兴工业化国家的交织;突破传统束缚,发挥“... 详细信息

本文着重从相对发展差距,国际竞争格局,优、劣势比较和转化着眼,探讨高技术产业的发展战略。强调要“机制挂帅”,建立适宜的环境和支撑结构;要面向世界市场,提高和发达国家的结合层次,扩展和新兴工业化国家的交织;突破传统束缚,发挥“跟进效应”,在提高国际竞争能力和增值上下功夫。

关键词：高技术产业

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轧制力预报问题中动态网络模型的实现

钢铁 2006年第12期41卷 49-52页

作者：董敏刘才李国友燕山大学机械工程学院河北秦皇岛066004 燕山大学电气工程学院河北秦皇岛066004

为提高轧制过程轧制力预报精度,建立了将轧制接触面积由几何关系确定,将影响因素复杂的轧制单位压力通过RBF神经网络预测模型。为适应工况的改变,提出了一种在线动态调整算法,利用新的测试数据对网络进行重新训练,使模型能够调整结构及... 详细信息

为提高轧制过程轧制力预报精度,建立了将轧制接触面积由几何关系确定,将影响因素复杂的轧制单位压力通过RBF神经网络预测模型。为适应工况的改变,提出了一种在线动态调整算法,利用新的测试数据对网络进行重新训练,使模型能够调整结构及网络参数,从而使最终设计的网络具有最佳结构。试验研究证明,所设计模型具有良好的适应能力,提高了轧制力的预报精度。

关键词：轧制力预测神经网络动态设计

改进的PCNN与Otsu的图像增强方法研究

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系统仿真学报 2005年第6期17卷 1370-1372页

作者：李国友李惠光吴惕华燕山大学电气工程学院秦皇岛066004 河北省科学院石家庄05000

提出了基于改进脉冲耦合神经网络(PCNN)与Otsu的图像模糊增强方法,该方法即可有效地去除噪声,又能根据图像灰度性质自动选取最佳阈值,并采用模糊集理论实现了图像的增强。计算机仿真表明,该方法可得到优于传统方法去噪和增强效果,从而... 详细信息

提出了基于改进脉冲耦合神经网络(PCNN)与Otsu的图像模糊增强方法,该方法即可有效地去除噪声,又能根据图像灰度性质自动选取最佳阈值,并采用模糊集理论实现了图像的增强。计算机仿真表明,该方法可得到优于传统方法去噪和增强效果,从而验证了该方法的有效性、合理性。

关键词：脉冲耦合神经网络 Otsu 阈值模糊集图像增强