考虑材料熔化潜热的高温高压本构

本文在修正的SCG模型基础上，提出了一种考虑了熔化潜热的高温高压本构.该本构所给出的铝的剪切模量的变化分为三个阶段：加工硬化，温度软化和熔化，并在完全熔化点处变为零.并且在前两个阶段，计算的结果与修正的SCG模型所给出的剪切模量的差别不超过4%，这一差别是在动高压实验误差范围之内的，在熔化区所给出的剪切模量与现有的实验数据相符合. 关键词： 剪切模量 熔化潜热 修正的SCG模型 动高压实验     

一类脉冲中立型时滞抛物方程组的振动性

研究一类脉冲中立型时滞抛物方程组解的振动性,得到了该类方程组在两类不同边界条件下所有解振动的若干充分条件.     

On bulk-service MAP/PH L,N /1/N G-Queues with repeated attempts

We consider a retrial queue with a finite buffer of size N, with arrivals of ordinary units and of negative units (which cancel one ordinary unit), both assumed to be Markovian arrival processes. The service requirements are of phase type. In addition, a PH^L,N bulk service discipline is assumed. This means that the units are served in groups of size at least L, where 1≤ L≤ N. If at the completion of a service fewer than L units are present at the buffer, the server switches off and waits until the buffer length reaches the threshold L. Then it switches on and initiates service for such a group of units. On the contrary, if at the completion of a service L or more units are present at the buffer, all units enter service as a group. Units arriving when the buffer is full are not lost, but they join a group of unsatisfied units called “orbit”. Our interest is in the continuous-time Markov chain describing the state of the queue at arbitrary times, which constitutes a level dependent quasi-birth-and-death process. We start by analyzing a simplified version of our queueing model, which is amenable to numerical calculation and is based on spatially homogeneous quasi-birth-and-death processes. This leads to modified matrix-geometric formulas that reveal the basic qualitative properties of our algorithmic approach for computing performance measures. AMS Subject Classification: Primary 60K25 Secondary 68M20 90B22.     

中心—焦点区分问题的I l'yashenko算法

对二维平面系统的二维系统的中心焦点区分问题 ,I l'yashenko曾建议一个算法 ,本文给出此法的详细证明 .据此 ,我们讨论了区分问题在 Arnold意义下的代数可解性与不可解性     

相型同步启动时间的M／M／c排队系统

本文研究带有同步启动时间的Ｍ／Ｍ／ｃ系统，其中启动时间是相型变量，给出了稳态和等待时间分布等结果。     

COMPLETE EXTREMAL SURFACES OF MIXED TYPE IN 3-DIMENSIONAL MINKOWSKI SPACE

ＣＯＭＰＬＥＴＥＥＸＴＲＥＭＡＬＳＵＲＦＡＣＥＳＯＦＭＩＸＥＤＴＹＰＥＩＮ３－ＤＩＭＥＮＳＩＯＮＡＬＭＩＮＫＯＷＳＫＩＳＰＡＣＥ￥ＧＵＣＨＡＯＨＡＯ（ＩｎｓｔｉｔｕｔｅｏｆＭａｔｈｅｍａｔｉｃｓ，ＦｕｄａｎＵｎｉｖｅｒｓｉｔｙ，Ｓｈａｎｇｈａｉ２００...     

Hyperbolic spaces are of strictly negative type

We study finite metric spaces with elements picked from, and distances consistent with, ambient Riemannian manifolds. The concepts of negative type and strictly negative type are reviewed, and the conjecture that hyperbolic spaces are of strictly negative type is settled, in the affirmative. The technique of the proof is subsequently applied to show that every compact manifold of negative type must have trivial fundamental group, and to obtain a necessary criterion for product manifolds to be of negative type.

     

Na2CO3调质钙基脱硫剂硫化机理实验研究

对经Na2CO3溶液调质石灰石煅烧产物CaO的物理结构及硫化特性进行了研究,发现同等条件下调质后石灰石煅烧产物CaO(M-CaO)比未经调质的CaO(N-CaO)具有更高的钙转化率.利用XRD技术对CaO晶体结构进行了测定,通过比较二者的晶胞参数和晶格畸变度等并结合其孔特性,证实M-CaO之所以比N-CaO具有更高的钙转化率,是由于M-CaO比N-CaO具有更高的晶体缺陷浓度,使得在硫化反应过程中通过产物层的扩散具有更高的离子扩散率.     

位置参数估计量的损失函数之估计

本文考虑损失函数的估计问题,分别对于球对称分布和均匀分布情形给出了其参数的J-S型估计量的损失之估计,它们满足[1]中提出的条件(Ⅰ)和(Ⅱ).