基于减法聚类和快速紧密性函数的SF-FCM

首先结合减法聚类和模糊C-均值聚类各自的优点,运用减法聚类自适应地确定模糊C-均值聚类（FCM）的初始聚类数;然后,提出了改进的紧密性函数,以此改进用于确定FCM聚类结构的有效性函数.改进后的紧密性函数将对聚类结果贡献不大的数据予以剔除,使得算法适应能力更强,执行速度更快.实验结果表明,该快速紧密性函数是有效的,而且计算速度更快.     

高脉冲重复频率雷达混合滤波解距离模糊方法

针对高脉冲重复雷达距离模糊问题,提出一种新的混合滤波解距离模糊方法.通过把脉冲间隔数和脉冲间隔变化量作为目标待估计状态,对离散的脉冲间隔数、间隔变化量和连续的目标状态(位置和速度)进行混合滤波,从而将解距离模糊问题转换为对脉冲间隔数的估计问题.初始时刻,由于距离量测模糊,利用多个高脉冲重复频率(HPRF)采用欧氏距离对混合状态进行初始化.在滤波过程中,为了避免门限选择,首先根据脉冲间隔变化量的有限个离散取值,将六维向量的混合滤波模型等效为有限个五维向量的混合滤波模型;然后对量测分别进行混合滤波;最后通过对各模型得到的新息的2范数进行比较获得混合状态估计,从而实现解距离模糊.混合滤波解距离模糊方法为实现高脉冲重复频率雷达实时解距离模糊提供了一种新的研究思路,仿真结果表明,本文提出的混合滤波方法在只有一个脉冲重复频率获得目标量测时较现有多假设方法收敛速度快,并且可以克服多假设方法在脉冲间隔数变化时发生的解模糊错误.     

新型泵类产品密封性测试系统

介绍一种基于ＵＳＯＮ４０００的泵类产品密封性测试系统的组成、工作原理以及气源、夹具和控制台与ＵＳＯＮ４０００主机的接口设计。     

圆筒形件不用压边多次拉深时的皱曲预报

在建立皱曲模型的基础上，由压缩塑性失稳临界载荷公式导出了圆筒形件不用压边拉深时的皱曲临界切向压应力的表达式。进而给出了不皱曲的判定式及其皱曲临界曲线。通过实验验证和对照分析，证明在实际生产中可直接使用不皱曲的判定式或皱曲临界曲线对拉深作皱曲预报，且精度和可靠性较高。     

Effect of tempering temperature on microstructure and mechanical properties of high boron white cast iron

The effect of different tempering temperatures on the microstructure and mechanical properties of airquenched high boron white cast iron was studied.The results indicate that the high boron white cast iron comprises dendritic matrix and inter-dendritic M 2 B boride;and the matrix comprises martensite and pearlite.After quenching in the air,the matrix is changed into lath martensite;but only 1-μm-size second phase exists in the matrix.After tempering,another second phase of several tens of nanometers is found in the matrix,and the size and quantity increase with an increase in tempering temperature.The two kinds of second precipitation phase with different sizes in the matrix have the same chemical formula,but their forming stages are different.The precipitation phase with larger size forms during the austenitizing process,while the precipitation phase with smaller size forms during the tempering process.When tempered at different temperatures after quenching,the hardness decreases with an increase in the tempering temperature,but it increases a little at 450 ℃ due to the precipitation strengthening effect of the second phase,and it decreases greatly due to the martensite decomposition above 450 ℃.The impact toughness increases a little when tempered below 300 ℃,but it then decreases continuously owing to the increase in size and quantity of the secondary precipitate above 300 ℃.Considered comprehensively,the optimum tempering temperature is suggested at 300 ℃ to obtain a good combination of hardness and toughness.     

二次采样随机共振的工程应用研究

研究了小参数随机共振(SR)理论的克莱默斯(Kramers)逃逸速率和罗伦兹(Lorentzian)分布的噪声频谱特性，得出了只有在噪声能量集中的低频区域才能产生随机共振的论点。在此基础上，通过二次采样频率变换思想，成功地将小参数随机共振扩展应用到大参数的随机共振，从而实现了从强噪声中检测出弱信号的目的。大参数随机共振谱特性及其信噪比的进一步定量分析表明，提高采样频率可把弱信号移入噪声能量集中的低频区域，有利于产生可辨识的随机共振谱峰。电机故障的监测与诊断实例证明了该方法在实际应用中的有效性。     

Have Chinese universities embraced their third mission? New insight from a business perspective

Have Chinese universities, after enormous investment over the past decade, embraced the university’s third mission—contributing to industrial and technological progress? The literature has not sufficiently addressed this question. This study intends to advance understanding of this issue by empirically addressing this question from a business perspective in a bold and unconventional way. Unlike prior studies that simply used contingent and institutional factors to describe the link between Chinese universities and industrial firms by measuring such aspects as patent licensing, co-patenting, and co-authoring, our work goes further and applies longitudinal analysis to examine the ways firms access university-level knowledge and the impact of such knowledge on firm innovation outputs. We propose that if Chinese universities embraced their third mission, then we would observe a positive effect of university–industry collaborations on firms’ subsequent innovation outputs. Empirical results based on a sample of the top 100 Chinese electronic firms in terms of output value support our hypothesis. Specifically, university patent licensing and co-patenting between universities and firms was found to positively affect firm innovation outputs. Moreover, we found that geographical distance and collaboration dominance moderate the co-patenting–innovation output relationship.     

生物质全降解材料微观组织结构与性能关系研究

以采用植物纤维(稻草纤维)、淀粉为主料,通过发泡成型工艺制成的生物质全降解材料为研究对象,研究了该材料在成型过程中气泡孔的生长机理,并采用扫描电子显微镜微区化学分析技术对4种植物纤维、淀粉、发泡剂不同含量的生物质全降解材料微观组织结构进行实验研究。结果表明生物质全降解材料中的植物纤维的连接形式是相互交叉的立体网状结构;发泡剂含量为1.0%时,生物质全降解材料形成的气泡孔为封闭结构且分布比较均匀,这种均匀的结构保证了材料良好的抗冲击性、反弹性和隔热保温性。     

New method for measuring the degree of conflict among general basic probability assignments

There is doubt about Dempster’s rule of combination because of counter-intuitive results when dealing with conflict information in intelligent reasoning.Therefore,many modified combination rules have been presented in the literature on multi-source information fusion and reasoning with uncertainty.However,the issue of identifying conflict among evidence has been ignored.A new parameter measuring conflict evidence called the conflict distance parameter is defined to determine whether there are conflicts in evidence based on the analysis of existing conflict parameters.At the same time,a decisive rule,which a reasonable conflict measure function should satisfy,is put forward.Finally,an analysis of two typical counter-intuitive situations is given,showing that the new parameter can not only satisfy the decisive rule,but can also attain the same effect as a two-dimensional measure when deciding whether to use the Dempster’s rule of combination,and can exceed its effect when deciding whether to use Dezert-Smarandache theory.     

高档普采工作面生产系统可靠性分析

通过对高档普采工作面生产系统的结构分析，构造简化马尔可夫图及可修复串联系统可靠性指标函数，并通过实例计算，得出分析结论。