CL-20基混合炸药的冲击起爆特征

为了研究CL-20基混合炸药的冲击起爆特征,深入分析冲击波作用下CL-20基混合炸药的爆轰成长规律,采用炸药驱动飞片冲击起爆实验方法,对CL-20、CL-20/NTO和CL-20/FOX-7三种压装混合炸药进行了冲击起爆实验,通过嵌入在炸药内部不同位置处的锰铜压力传感器,获得了炸药内部压力的变化历程。依据实验结果标定了混合炸药的点火增长模型参数,其中,利用反应速率方程中的两个增长项,分别模拟CL-20/NTO和CL-20/FOX-7混合炸药中两种组分的反应增长过程,得到这两种混合炸药的反应速率方程参数。并通过数值模拟的方法得到了三种炸药的临界起爆阈值和POP关系。研究结果表明：三种CL-20基混合炸药中,CL-20/NTO混合炸药具有更高的临界起爆阈值,而CL-20/FOX-7混合炸药具有更长的爆轰成长距离;此外,利用此套拟合双组分混合炸药反应速率方程的方法,可以对新型配方炸药的冲击起爆过程进行预测性计算

     

基于单片机的GPS定位信息处理

为了保障舰船在海上能够快速有效的定位,并且实现全球定位功能,本文介绍了一项利用单片机采集和处理GPS定位信息的设计。该系统以ATMEL公司的AT89C51单片机为核心控制器件,通过串行口与GPS模块HOLUXGR87通信,接收GPS模块输出的时间和定位信息,该输出信息格式采用NMEA-0183标准格式中的GPRCM语句。单片机接收到定位信息和时间信息后,将GPS模块输出的时间信息进行时差调整,再将所获取的位置和时间信息通过显示终端显示。经过调试后,本系统可以接收GPS定位信息和时间信息,并把经度、纬度和时间通过屏幕显示出来。     

Visible-light photocatalytic activity of the metastable Bi20TiO32 synthesized by a high-temperature quenching method

Metastable Bi₂₀TiO₃₂ samples were synthesized by a high-temperature quenching method using α-Bi₂O₃ and anatase TiO₂ as raw materials. The photocatalytic activity of the as-prepared samples was measured with the photodegradation of methyl orange at room temperature under visible light irradiation. The Bi₂₀TiO₃₂ samples exhibited good absorption in the visible light region with a band gap of about 2.38 eV and the band structure of Bi₂₀TiO₃₂ was studied. Photodegradation against methyl orange was much better than α-Bi₂O₃ prepared by the same way. The photocatalytic activity of Bi₂₀TiO₃₂ samples is supposed to be associated with the hybridized Bi 6s and O 2p orbitals. In addition, the dispersive characteristic of Bi 6s orbital in the hybridized valence band facilitates the mobility of the photogenerated carriers and hampers their recombination.     

Congruence criteria for finite subsets of complex projective and complex hyperbolic spaces

We investigate congruence classes and direct congruence classes of m-tuples in the complex projective space ℂP ⁿ . For direct congruence one allows only isometries which are induced by linear (instead of semilinear) mappings. We establish a canonical bijection between the set of direct congruence classes of m-tuples of points in ℂP ⁿ and the set of equivalence classes of positive semidefinite Hermitean m×m-matrices of rank at most n+1 with 1's on the diagonal. As a corollary we get that the direct congruence class of an m-tuple is uniquely determined by the direct congruence classes of all of its triangles, provided that no pair of points of the m-tuple has distance π/2. Examples show that the situation changes drastically if one replaces direct congruence classes by congruence classes or if distances π/2 are allowed. Finally we do the same kind of investigation also for the complex hyperbolic space ℂH ⁿ . Most of the results are completely analogous, however, there are also some interesting differences. Received: 15 January 1996     

The ordinary quiver of a weight three block of the symmetric group is bipartite

Suppose F is a field of characteristic p?5, and that B is a p-block of the symmetric group Sn of defect 3. We prove that the Ext¹-quiver of B is bipartite, with the bipartition being described in a simple way using the leg-lengths of p-hooks of partitions.     

Essential Spectral Inclusions for Operators on Banach Spaces

This paper centers on local spectral conditions that are both necessary and sufficient for the equality of the essential spectra of two bounded linear operators on complex Banach spaces that are intertwined by a pair of bounded linear mappings. In particular, if the operators T and S are intertwined by a pair of injective operators, then S is Fredholm provided that T is Fredholm and S has property (δ) in a neighborhood of 0. In this case, ind(T) ≤ ind(S), and equality holds precisely when the eigenvalues of the adjoint T* do not cluster at 0. By duality, we obtain refinements of results due to Putinar, Takahashi, and Yang concerning operators with Bishop’s property (β) intertwined by pairs of operators with dense range. Moreover, we establish an extension of a result due to Eschmeier that, under appropriate assumptions regarding the single-valued extension property, leads to necessary and sufficient conditions for quasi-similar operators to have equal essential spectra. In particular it turns out that the single-valued extension property plays an essential role in the preservation of the index in this context.      

On the existence of solutions to a special variational problem

In this paper we establish an existence and regularity result for solutions to the problem

Algorithmically random series and Brownian motion

We consider some random series parametrised by Martin-Löf random sequences. The simplest case is that of Rademacher series, independent of a time parameter. This is then extended to the case of Fourier series on the circle with Rademacher coefficients. Finally, a specific Fourier series which has coefficients determined by a computable function is shown to converge to an algorithmically random Brownian motion.     

A Computationally Motivated Definition Of Parametric Estimation And Its Applications To The Gaussian Distribution

We introduce a treatment of parametric estimation in which optimality of an estimator is measured in probability rather than in variance (the measure for which the strongest general results are known in statistics). Our motivation is that the quality of an approximation algorithm is measured by the probability that it fails to approximate the desired quantity within a set tolerance. We concentrate on the Gaussian distribution and show that the sample mean is the unique “best” estimator, in probability, for the mean of a Gaussian distribution. We also extend this method to general penalty functions and to multidimensional spherically symmetric Gaussians. The algorithmic significance of studying the Gaussian distribution is established by showing that determining the average matching size in a graph is #P-hard, and moreover approximating it reduces to estimating the mean of a random variable that (under some mild conditions) has a distribution closely approximating a Gaussian. This random variable is (essentially) polynomial time samplable, thereby yielding an FPRAS for the problem.     

五羟色胺分子选择性电极研究

本应用自己合成的联萘２０－冠－６作为活性载体，进行了五羟色胺分子选择性电极研究。电极在１０＾－＾５－１０＾－＾２ｍｏｌ／Ｌ浓度范围内对五羟色胺具有稳定的线性响应，平均斜率为６３ｍＶ／ＰＣ，检测下限为２．７×１０＾－＾６ｍｏｌ／Ｌ。