The streamline-diffusion method for nonconforming Qrot1 elements on rectangular tensor-product meshes

When the streamline–diffusion finite element method isapplied to convection–diffusion problems using nonconformingtrial spaces, it has previously been observed that stabilityand convergence problems may occur. It has consequently beenproposed that certain jump terms should be added to the bilinearform to obtain the same stability and convergence behaviouras in the conforming case. The analysis in this paper showsthat for the Q^rot₁ 1 element on rectangular shape-regular tensor-productmeshes, no jump terms are needed to stabilize the method. Inthis case moreover, for smooth solutions we derive in the streamline–diffusionnorm convergence of order h^3/2 (uniformly in the diffusion coefficientof the problem), where h is the mesh diameter. (This estimateis already known for the conforming case.) Our analysis alsoshows that similar stability and convergence results fail tohold true for analogous piecewise linear nonconforming elements.     

Primal-Dual Solution Perturbations in Convex Optimization

Solutions to optimization problems of convex type are typically characterized by saddle point conditions in which the primal vector is paired with a dual multiplier vector. This paper investigates the behavior of such a primal-dual pair with respect to perturbations in parameters on which the problem depends. A necessary and sufficient condition in terms of certain matrices is developed for the mapping from parameter vectors to saddle points to be single-valued and Lipschitz continuous locally. It is shown that the saddle point mapping is then semi-differentiable, and that its semi-derivative at any point and in any direction can be calculated by determining the unique solutions to an auxiliary problem of extended linear-quadratic programming and its dual. A matrix characterization of calmness of the solution mapping is provided as well.     

A Load-Balanced Network with Two Servers

A load-balanced network with two queues Q ₁ and Q ₂ is considered. Each queue receives a Poisson stream of customers at rate _i , i=1,2. In addition, a Poisson stream of rate arrives to the system; the customers from this stream join the shorter of two queues. After being served in the ith queue, i=1,2, customers leave the system with probability 1–p _i ^*, join the jth queue with probability p(i,j), j=1,2, and choose the shortest of two queues with probability p(i,{1,2}). We establish necessary and sufficient conditions for stability of the system.     

Stability of Earliest-Due-Date,First-Served Queueing Networks

We study multiclass queueing networks with the earliest-due-date, first-served (EDDFS) discipline. For these networks, the service priority of a customer is determined, upon its arrival in the network, by an assigned random due date. First-in-system, first-out queueing networks, where a customer's priority is given by its arrival time in the network, are a special case. Using fluid models, we show that EDDFS queueing networks, without preemption, are stable whenever the traffic intensity satisfies _j <1 for each station j.     

管内电缆导体稳定性理论与实验研究

管内电缆导体 ,又称 CICC,是目前大型低温超导磁体的首选导体。随着超导技术的发展 ,CICC在大型超导核聚变实验装置及超导储能磁体中的应用具有不可比拟的优越性。为降低导体成本而提出了在 CICC中采用的超导股线配以纯铜股线的设计方案 ,开展含纯铜股线 CICC稳定性机理及实验的研究 ,并开发 CICC优化设计软件 ,对 CICC在高科技中的应用意义重大。     

Problems of the Theory of Rated Stability

Consider a new concept of stability of the so-called rated motion of a system of an ordinary differential equations. A rated motion need not be a solution of this system at all. In terms of Lyapunovs direct method, formulate and prove certain statements about rated stability, asymptotically rated stability, and rated unstability of zero motion of a system of an ordinary differential equations.AMS Subject Classification (1991): 34D05 34D35 93D30 93D20     

Noise Stability of SIS Receivers

There is a strong interest in the submillimeter astronomy community to increase the IF bandwidth of SIS receivers in order to better facilitate broad spectral linewidth and continuum observations of extragalactic sources. However, with an increase in receiver IF bandwidth there is a decrease in the mixer stability. This in turn effects the integration efficiency and quality of the measurement. In order to better understand the noise mechanisms responsible for reducing the receiver stability, we employed a technique first described by D.W. Allan and later elaborated upon by Schieder et al. In this paper we address a variety of factors that degrade the noise stability of SIS receivers. The goal of this exercise is to make recommendations aimed at maximizing SIS receiver stability.     

Calculating Helix-to-Coil Transitions of Duplexes Formed by Phenazine-Conjugated Oligonucleotide, Using Flourescence Melting Data

A novel intercalating phenazine derivative (Pzn) was covalently linked to the 3-end of decathymidylate via a ribose residue of the dye. A fluorescence technique was used to study double helix formation by this conjugate with poly(rA) in aqueous solutions of neutral pH, at the presence of 0.1 and 1 M sodium ions. Proportionality between thermally induced changes in the fluorescence intensity of the free conjugate and bound one was revealed, that made it possible to calculate the helix-to-coil transition from fluorescence melting data using a simple equation. The transition curves were found to be in well conformity with those constructed from absorption measurements. It was shown that the attachment of Pzn significantly enhanced the stability of poly(rA) · (dT)₁₀ duplex due to intercalation of the dye chromophore into the adenine strand. The temperature of half-dissociation was increased by 12°C, and the stabilizing increment of standard free energy was 3.2–3.6 kcal/mol at 37°C.     

一类参数不确定统一混沌系统的脉冲滞后同步

针对一类具有传输信道时间延迟且参数不确定的统一混沌系统，提出了一种脉冲控制同步方法.该方法将两个非自治混沌系统之间脉冲同步的实用稳定性问题转化为同步误差系统在原点的实用稳定性问题，基于脉冲微分方程的相关理论，给出了同步误差系统在原点的实用稳定判据，仿真结果验证了方法的有效性. 关键词： 统一混沌系统 混沌同步 脉冲控制 实用稳定性     

LD抽运被动调Q固体激光器的脉冲稳定性

报道了二极管激光抽运Cr,Nd∶YAG被动调Q Nd∶YVO₄ 1064nm激光输出.为了提高被动调Q激光的输出稳定性，谐振腔采用长腔，增益介质位于谐振腔中间位置.实验中获得了稳定的被动调Q激光输出.在最高入射抽运功率为17.5W时，脉冲重复频率达到71.3kHz，脉冲宽度为0.4μs.调Q脉冲幅度不稳定性低于±10%，脉冲时间波动性低于±3.5%.