带有阈值控制策略的M/M/1多重休假排队模型

本文研究带有阈值控制策略的M/M/1多重休假排队模型.当一次服务结束时,根据系统中顾客数的不同,服务台可能进入普通休假,也可能进入工作休假或进入正规忙期.对该模型,应用拟生灭(QBD)过程和矩阵几何解的方法,我们得到了平稳队长的具体形式.在此基础上,我们进一步给出了平稳队长和平稳等待时间的条件随机分解结果、附加队长的概率母函数(PGF)以及附加延迟的Laplace-Stieltjes变换(LST)的具体形式.     

Computing transient performance measures for the M/M/1 queue

A practically important problem is the computation of transient performance measures for the M/M/1 queue. Trigonometric integral representations are very well suited for that purpose. This paper reviews a number of results that can be found scattered in the literature and also provides the practitioner simple recommendations for calculating routinely the M/M/1 performance measures.     

CUSUM Statistical Monitoring of M/M/1 Queues and Extensions

Many production and service systems can be modeled as queueing systems. Their operational efficiency and performance are often measured using queueing performance metrics (QPMs), such as average cycle time, average waiting length, and throughput rate. These metrics need to be quantitatively evaluated and monitored in real time to continuously improve the system performance. However, QPMs are often highly stochastic, and hence are difficult to monitor using existing methods. In this article, we propose the cumulative sum (CUSUM) schemes to efficiently monitor the performance of typical queueing systems based on different sampling schemes. We use M/M/1 queues to illustrate how to design the CUSUM chart and compare their performance with several alternative methods. We demonstrate that the performance of CUSUM is superior, responding faster to many shift patterns through extensive numerical studies. We also briefly discuss the extensions of CUSUM charts to more general queues, such as M/G/1, G/G/1, or M/M/c queues. We use case studies to demonstrate the applications of our approach. Supplementary materials for this article are available online.     

M1等级砝码测量结果的不确定度评定

本文根据M1等级砝码标准装置,结合JJG555-1996《非自动秤通用检定规程》要求,对M1等级砝码测量结果的不确定度进行评定。     

半马尔可夫过程在GI/M/1和M/G/1排队系统中的应用

本文运用齐次可列半马尔可夫过程的向后方程和向前方程,分别研究了GI/M/1和M/G/1排队系统队长的瞬时分布.首先得到了GI/M/1队长的转移概率的拉普拉斯变换满足的向后方程组,然后得到了M/G/1队长的转移概率的拉普拉斯变换满足的向前方程组,所得方程组的系数矩阵都是拟下三角矩阵,都可以通过迭代法进行求解.     

HL—1M的原位处理技术

介绍 Ｈ Ｌ－ １ Ｍ 托卡马克装置的壁处理技术。使用氦辉光放电清洗清除装置杂质和降低壁中氢含量,壁硼化和硅化技术以及原位沉积膜的原位清除。     

HL—1M装置内壁锂化实验进展

针对聚变装置在聚变研究中的器壁原位处理问题,详细地描述了HL-1M装置原位锂化技术和锂涂层性能及其锂化效果,并探讨了锂化机理.指出了这种锂化工艺存在的缺陷.     

M_1等级砝码测量值的不确定度评定

依据JJG99-2006《砝码检定规程》对M1等级砝码测量值的不确定度进行分析。     

M_1等级砝码测量值的不确定度评定

依据JJG99-2006《砝码检定规程》对M1等级砝码测量结果的不确定度进行分析。     

Corrosion-Electrochemical Behavior of M1 Copper in Aqueous Ethylene-Glycol Media

In aqueous ethylene-glycol media, M1 copper oxidizes to Cu⁺ ions. In the course of corrosion, dissolved oxygen oxidizes ethylene glycol and Cu⁺ ions to Cu^{2 +} ions, which, together with ethylene glycol and the products of its oxidation, form complex compounds. In the case of deep ion-exchange purification of a water-ethylene-glycol heat carrier (ρ = 100 kΩ · m), the maximum value of the coefficient of protective action is 70%. With decrease in the concentration of dissolved oxygen to 1 g/m³, under conditions of minimum purification ρ = 5 kΩ · m), this parameter constitutes 77% and grows to 97% for a specific electric resistance of the heat carrier of 50 kΩ · m. Combining both methods of the removal of corrosion-active admixtures (dissolved oxygen and the products of copper and ethylene glycol oxidation), one can enhance substantially the corrosion resistance of copper in water-ethylene-glycol heat carriers.__________Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 41, No. 1, pp. 19 – 26, January – February, 2005.     

HL-1M等离子体加料密度特性

主要介绍ＨＬ－１Ｍ托卡马克装置三种加料方式所得的密度的特性结果。用弹丸注入（ＰＩ）、超声分子束注入（ＳＭＢＩ）和常规脉冲送气（ＧＰ）获得等离子体电子密度Ｎｅ分别为５．３＊１０＾１９ｍ＾－３,８＊１０＾１９ｍ＾－３和７＊１０＾１９ｍ＾－３。前者获得的能量约束时间τｅ却比后者高３０％以上。比较了不同再循环条件下各种加料实验的结果,由密度演变、Ｈ信号和软射线（ＳＸ）信号的时空变化显示三种加料方式粒子沉积     

HL—1M装置的氦辉光放电清洗的清除率研究

通过对ＨＬ－１Ｍ的氦直流辉光放电清洗（ＨｅＧＤＣ）的放电特点和清除效率的研究，发现环形真空室的对称性导致与阳极截面相对称的区域的场强很弱，使其阴极位降区的厚度远大于氦离子的平均自由程，严重影响辉光清除效率。提出采用多电极不对称阳极电位的辉光放电来提高清除效率。     

Thermal conductivity of single crystals of M1−x M x ′F2 (M = Ca, Sr; M′ = Mn, Co) isovalent solid solutions

The thermal conductivity of single crystals of the Ca_0.99Co_0.01F₂, Ca_0.97Co_0.03F₂, Sr_0.99Mn_0.01F₂, Sr_0.989Mn_0.01Co_0.001F₂, and Sr_0.995Co_0.005F₂ solid solutions has been measured in the temperature range 50–300 K. The results demonstrate that doping of CaF₂ and SrF₂ crystals with small amounts of isovalent transition metal impurities is accompanied by a significant reduction in thermal conductivity.     

Symmetry relationship and strain-induced transitions between insulating M1 and M2 and metallic R phases of vanadium dioxide

The ability to synthesize VO2 in the form of single-crystalline nanobeams and nano- and microcrystals uncovered a number of previously unknown aspects of the metal-insulator transition (MIT) in this oxide. In particular, several reports demonstrated that the MIT can proceed through competition between two monoclinic (insulating) phases M1 and M2 and the tetragonal (metallic) R phase under influence of strain. The nature of such phase behavior has been not identified. Here we show that the competition between M1 and M2 phases is purely lattice-symmetry-driven. Within the framework of the Ginzburg-Landau formalism, both M phases correspond to different directions of the same four-component structural order parameter, and as a consequence, the M2 phase can appear under a small perturbation of the M1 structure such as doping or stress. We analyze the strain-controlled phase diagram of VO2 in the vicinity of the R-M2-M1 triple point using the Ginzburg-Landau formalism and identify and experimentally verify the pathways for strain-control of the transition. These insights open the door toward more systematic approaches to synthesis of VO2 nanostructures in desired phase states and to use of external fields in the control of the VO2 phase states. Additionally, we report observation of the triclinic T phase at the heterophase domain boundaries in strained quasi-two-dimensional VO2 nanoplatelets, and theoretically predict phases that have not been previously observed.