Approximate Degree Reduction of Triangular Bezier Surfaces

ＡｐｐｒｏｘｉｍａｔｅＤｅｇｒｅｅＲｅｄｕｃｔｉｏｎｏｆＴｒｉａｎｇｕｌａｒＢｅｚｉｅｒＳｕｒｆａｃｅｓ＊ＨｕＳｈｉｍｉｎ（胡事民）,ＺｕｏＺｈｅｎｇ（左征）,ＳｕｎＪｉａｇｕａｎｇ（孙家广）ＤｅｐａｒｔｍｅｎｔｏｆＣｏｍｐｕｔｅｒＳｃｉｅｎｃｅａｎ...     

旋风除尘器内锥形扩口芯管对其性能的影响分析和实验研究

用平衡粒径模型分析了旋风除尘器内常用的柱菜芯管结构存在的缺陷,提出了用带锥形扩口和十字板的芯管改进旋风除尘器的内部芯管结构,并用实验研究测得了新型结构减阻效的幅度。     

脉冲爆震发动机的推力测试与分析

对脉冲爆震发动机产生的推力进行了定量测定与分析,研究了混气余气系数、起爆频率和爆震频率对脉冲爆震发动机推力的影响规律．同时,通过推力的测定以验证发动机性能计算方法的正确性,掌握脉冲爆震发动机推力测试的方法．研究表明,推力测试值与理论计算值吻合较好．     

奇异值估计的Brauer型定理

设Ａ＝（ａｉｊ）为ｎ阶复矩阵．记ｓｉ＝ｍａｘ∑ｊ≠ｉ｜ａｉｊ｜,∑ｊ≠ｉ｜ａｊｉ｜｛｝,ａｉ＝｜ａｉ｜（ｉ＝１,２,…,ｎ）．证明了Ａ的奇异值均属于Ｂｒａｕｅｒ型并集∪ｉ≠ｊｚ≥０：｜ｚ－ａｉ｜｜ｚ－ａｊ｜≤ｓｉｓｊ｛｝,并给出了该并集的显式表达及数值例子．     

一种同时求解多项式重根的迭代方法及其收敛性

本文给出一种三阶收敛的同时求解多项式重根的迭代方法,并分析该分法收敛的初始值条件,我们也给出算例。     

WAVELET PACKET AND FUZZY NEURAL NETWORK FOR TOOL CONDITION MONITORING *

在自动化制造中,线监控刀具状况以保护刀具与加工工件显得越来越重要．近年来,许多研究者在此领域进行了广泛的研究,然而由于加工过程的不确定性,现有的刀具监控系统的可靠性还有待提高．本文提出了一种基于小波包分析与模糊神经网络的自适应刀具监控系统,该系统利用小波包分析方法将加工过程振动信号分解为不同的频率段,并在此基础上,建立了自适应特征提取方法,为模糊神经网络提供最优的特征输入,然后模糊神经网络据此进行决策,分析刀具磨损状况．实验结果表明：该系统模糊神经网络能有效通过学习人类模糊知识和在线学习样本来提高刀具监控精度．     

Effects of atmospheric pollution on human health

Most air pollutants do not lead to specific diseases. Depending on the pollutant, the concentration and the duration of exposure, some organs are more affected than others. The most frequent disorders are those caused by irritant gases and particulates on the mucous membranes and respiratory organs. The consequences are eye, nose and throat inflammations, diminished lung function, increased susceptability to respiratory infection and a higher incidence of chronic bronchitis. These disorders and diseases are, of course, influenced by other factors as well, such as immune deficiency, allergies, occupational exposure to pollutants, and particularly smoking. The effects of air pollutants are, therefore, multifactorially conditioned and nonspecific disorders are placed in the foreground. Evidence for an association of air pollution with adverse effects on human health is drawn from three sources: animal experiments, experimental human exposures, and epidemiologic studies of exposed human populations. The burden of atmospheric pollution must be reduced to protect human health by an adequate safety margin. In particular, the increased sensitivity of sick and aged people as well as children should be taken into account. In defining the maximum emmission levels, preventive aspects should have priority so as to keep the risk of damage to health and the harmful influences on the environment to a minimum.This article Effects of atmospheric pollution on human health by H. U. Wanner is a revised version of the same article that was first published in the Proceedings of the 1990 European Aerosol Conference; special issue of the J. Aerosol Sci., Vol. 21, Suppl. 1 (1990) 389–396.Reprinted with kind permission from Pergamon Press Ltd, Headington Hill Hall, Oxford OX3 0BW, Great Britain.     

黑龙江省篮球裁判员培养现状调查与对策研究

采用文献资料法、问卷调查法、访谈法和数理统计法,对黑龙江省篮球裁判员的基本现状进行了调查研究,旨在加强黑龙江省篮球裁判员的队伍建设.     

底栖无脊椎动物群落与生物监测

利用无脊椎动物群落作为生物监测的条件，将具有潜在胁迫的系统与未受干扰的基准区群落进行比较，以评价测试系统的状态．着重讨论了基准条件法建模过程及结果的分析方法，并提出了其应用前景．     

Esscher-变换与风险测度技术

通过研究精算学中Esscher 变换技术及其对于金融市场中风险资产无套利原则的刻画,反映其在金融市场风险管理技术中的应用,证明了无套利原则、等价鞅测度的存在性和Esscher 变换在所建立的Hilbert 空间下的一致性,并建立了在无套利条件下求解鞅性成立的Esscher 变换下概率测度变换参数的方法。讨论了Esscher 变换在金融市场风险管理策略的选择问题中的应用,得到了组合融资最优策略的Esscher 变换参数的解析式。