高临界温度超导体的研究进展和前景

本文综合论述了1987年以来超导研究发展的动态、进展和预言了超导发展的前景。文章简述了超导物理学发展简史,并就超导起始转变温度、临界电流密度、超导线材、超导薄膜、超导器件、超导制备工艺、超导组分、超导相结构以及超导理论方面的进展分别作了介绍。并对超导发展的方向作了一定的评述。     

级数sum from n = 1 to ∞ ()[1/n~(2k)](K∈N)求和的一个递推公式

级数[1/n~(2k)]（Ｋ∈Ｎ）求和的一个递推公式王慧兴（河南驻马店高中４６３０００）取定Ｋ∈Ｎ，则无穷级数收敛。为得到其和，通常要用某个函数的Ｆｏｕｒｉｅｒ级数来完成，并且对不同的自然数Ｋ，要寻求不同函数的Ｆｏｕｒｉｅｒ级数，文献［１］用初等方法证明了等...     

浅谈有限域上的一元多项式

本文对有限域的一元多项式易混淆的几个问题作了初步讨论和说明．     

评《易》学研究中之“雷氏A—D密码”

《易经》６４个复卦，历来均将之一分为二即分解为两个单卦来说明其规律性，而《１０分钟周易》一书则提出用“雷氏Ａ—Ｄ密码”将之一分为三即分解为三个“四象”予以剖析．数学分析表明“雷氏Ａ—Ｄ密码”关于６４个复卦卦象所呈现的某些规律的一套说法确实符合二进制，但总的来说是失多得少，而用它来破译“敦煌古卦”和“中天八卦”也显得证据不力。     

Probabilistic Risk Analyses: NRC Programs and Perspectives

The historical basis and more recent activities and products of probabilistic risk analysis (PRA) in the Atomic Energy Commission and Nuclear Regulatory Commission (NRC) are reviewed. Current NRC program activities and objectives are described. The author's opinions on the best uses of PRA are presented.     

DELAY ESTIMATION BY A HILBERT TRANSFORM METHOD

This paper describes an estimation of the time delay between two stationary time series signals, in which an input signal is measured with little noise and an output signal is the sum of a noise and the response from a linear system. We use the Hilbert transform relation for minimum delay systems to estimate the time delay. Some computer simulation results are given to evaluate the performance of the proposed method.     

Recursive estimation of the mode of a multivariate density

Let f be an unknown possibly multimodal density on R^d and let X₁, X₂, … be a sequence of independent random vectors with density f. Several recursive estimates of the mode of f are proposed, and sufficient conditions ensuring their weak and strong consistency are established.     

A note on the joint distribution of correlated quadratic forms

In the present paper, the authors obtained exact and asymptotic expressions for the joint distribution of correlated quadratic forms when the underlying distribution is a multivariate normal.     

A note on the universal optimality criterion for full rank models

The aim of this note is to suggest a revised formulation of the universal optimality criterion for full rank models as stated in Kiefer (1975). We have presented the relevant results with indications of some possible applications.