二阶完全非线性抛物型方程的周期解

证明了二阶完全非线性抛物型方程周期粘性解的存在唯一性，在标准假设下解决了非线性抛物型方程古典周期解的存在唯一性问题。     

两类Chemotaxis模型解的性质

本文讨论了抛物-双曲和抛物-常微两个Chemotaxis模型初边值问题解的性质.利用形式级数展开的方法，得到全局解在微小扰动下，导致解在有限时间内爆破，并对爆破时间进行了估计.因此说明了这种模型空间齐性解的不稳定性。     

具有双障碍的退缩抛物变分不等式解的存在性和唯一性

本文研究具有双障碍的退缩抛物变分不等式，我们利用罚技巧，有限逼近和先验估计方法，得到一类退缩抛物变分不等式弱解的存在性，并在一定条件下，建立了弱解的唯一性。本文结论对广泛的一类抛物物型变分不等式成立。     

双非线性抛物组解的有界性

本文考虑对角型双非线性抛物型方程组，在一般结构条件下，证明广义解局部有界和整体有界，并对一特殊情形，证明了如果解在抛物边界为零，那么它只能是零解．     

一类非线性伪抛物型方程Cauchy问题的适定性

通过引入算子I-Δ的Bessel势将伪抛物型方程化成抽象的抛物型方程,然后利用算子半群理论讨论了一类非线性伪抛物型方程Cauchy问题的适定性问题.     

中立抛物型偏微分方程解的强迫振动

本讨论一类多滞量中立抛物型偏微分方程解的振动性物，获得了其一切解振动的充分条件，指出了与普通抛物型偏微分方程质的差异。     

一类时滞抛物型偏微分方程解的振动性质

在本文中，我们在不同边界条件下得到了一类具连续分布时滞抛物型偏微分方程解的振动性判据．     

双非线性抛物型方程非负解的一个性质

在Ｅ＾ｎ（０，∞）上讨论双非线性抛物型方程ａ／ａｔ（｜ｕ｜＾λ－２ｕ）－ｄｉｖ（｜△ｕ｜＾ｐ－２△ｕ）＝０在ｐ＞λ＞２的条件下，证明它的齐次Ｃａｕｃｈｙ问题非负整体解必是零解。     

自相似分形上的非线性抛物方程(英文)

本文研究了分形区域上的一类半线性抛物方程.对于分形上恰当定义的拉普拉斯算子,建立了抛物方程的比较原理.利用上下解方法,我们得到了在一定条件下半线性抛物方程正解的存在性和唯一性.     

带奇异项的半线性抛物方程全局解的渐近分析

本文考虑一类带奇异项的半线性抛物方程的初边值问题，利用标准的正则摄动方法和抛物方程的极值原理，对任意给定的正整数Ｎ、得到上述问题的全局古典解的Ｎ＋１阶一致近似计算公式。     

Oscillatory Behaviour of Solutions of Two-Dimensional Differential Systems with Deviated Arguments

Sufficient conditions are established for the oscillation of proper solutions of the system

矩阵方程X-A*X-2A=Q的正定解及其扰动分析

研究非线性矩阵方程X-A*X-2A=Q(Q>0)的Hermite正定解及其扰动问题.给出了该方程存在唯-Hermite正定解的充分条件及解的迭代计算公式.在此条件下,给出了该唯一解的扰动界及正定解条件数的一种表达式,并用数值例子对所得结果进行了说明.     

二阶矩阵微分系统振动的区间准则

本文研究了二阶矩阵微分系统的振动性：（Ｐ（ｔ）Ｙ＇）＇＋Ｑ（ｔ）Ｙ＝ ０,ｔ∈［ｔ０,∞）,其中Ｐ,Ｑ,Ｙ是ｎ×ｎ实矩阵函数,Ｐ（ｔ）,Ｑ（ｔ）是对称的且Ｐ（ｔ）正定．所得的准则仅依赖于系统在［ｔ０,∞）的一个子区间序列的信息而有别于已知的大多数结论,我们的结果更精确,并能应用于判别如极端情形．     

Left conjugacy closed loops of nilpotency class two

Every LCC loop Q with Inn Q abelian is nilpotent class two. A loop Q of nilpotency class two is LCC ? L(x, y) = L(y, x) for all x, y ∈ Q ? ?/Z(Mlt Q) is abelian ? [x, y, z] = [x,z,y] for all x, y, z ∈ Q ? [x, y, z] = [xy, z][x, z]^?1 for all x, y, z ∈ Q. All nilpotent LCC loops of order p² are described, and some of their multiplication groups are computed.     

On a partial regularity up to the boundary of weak solutions to quasilinear parabolic systems with quadratic growth

Quasilinear nondiagonal parabolic systems with quadratic growth in the gradient in a parabolic cylinder Q are considered. Under Dirichlet and Neumann boundary conditions, a partial Hölder continuity of solutions u∈W ₂ ^t,1 (Q)～L^∞ (Q) up to the lateral surface of Q is proved.The Hausdorff dimension of a singular set is estimated. In the proof, we get rid of the maximum principle theorem for respective model linear problems. Bibliography: 21 titles.     

Forbidden hyperfine transitions in electron spin resonance of Mn2+ in NaCl single crystal

Forbidden hyperfine transitions are observed in the electron spin resonance spectrum of divalent Mn⁵⁵ ion in NaCl single crystal for a particular associated pair. From the measurements of the M = + 1/2 → ?1/2, Δm = ± 1 transitions the parametersQ′ and Q″ of the nuclear electric quadrupole part of the spin-Hamiltonian H_o = Q′ [I_z ² ? 1/3 I (I + 1)] + Q″ (I_x ²?I_y ²) are found to be + 1.70 × 10^?4 cm.^?1 and +0.16 × 10^?4 cm.^?1 respectively.     

Zerfallende Quadrikenschnitte und stereographische Projektion

If the intersection of two quadrics Q ₁ ^n–1 , Q ₂ ^n–1 in projective space Pⁿ contains a quadric Q ₃ ^n–2 which is different from its singularity space, then the intersection Q ₁ ^n–1 Q ₂ ^n–1 is the union of two quadrics Q ₃ ^n–2 , Q ₄ ^n–2 . This theorem leads to a geometric characterization of those hyperquadrics of a hyperplane of Pⁿ that are images of quadrics on a given quadric Q^n–1 by a given stereographic projection of Q^n–1 onto .

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Herrn Prof. Dr.Oswald Giering zum 50. Geburtstag gewidmet     

A Note on Almost GCD Monoids

A commutative cancellative monoid H (with 0 adjoined) is called an almost GCD (AGCD) monoid if for x,y in H, there exists a natural number n = n(x,y) so that xⁿ and yⁿ have an LCM, that is, xⁿH \cap yⁿH is principal. We relate AGCD monoids to the recently introduced inside factorial monoids (there is a subset Q of H so that the submonoid F of H generated by Q and the units of H is factorial and some power of each element of H is in F). For example, we show that an inside factorial monoid H is an AGCD monoid if and only if the elements of Q are primary in H, or equivalently, H is weakly Krull, distinct elements of Q are v-coprime in H, or the radical of each element of Q is a maximal t-ideal of H. Conditions are given for an AGCD monoid to be inside factorial and the results are put in the context of integral domains.     

Oscillation of odd order delay differential equations

In this paper, we obtain the sufficient and necessary conditions for all solutions of the odd-order nonlinear delay differential equation.x ⁽ⁿ⁾+Q(t)f(x(g(t)))=0 to be oscillatory. In particular, ifn=1, Q(t)>0, f(x)=x ^α, where α∈(0,1) and is a ratio of odd integers andg(t)=t?? for some ?>0, then every solution of (*) oscillates if and only if ∫^∞Q(s)ds=∞.     

A Note on Constants of Integral Derivations in Semiprime Rings

Let R be a semiprime ring with extended centroid C and with Q its Martindale symmetric ring of quotients. Suppose that δ: R → R is a C-integral derivation. For a subring A of Q, let A^(δ) denote the subring of constants of δ in A. We prove that R^(δ) and Q^(δ) satisfy the same polynomial identities with coefficients in C. In particular, R^(δ) is not nil of bounded index.