ITER HTS电流引线批量件验收性测试系统

ITER(International Thermonuclear experimental Reactor)高温超导电流引线(HTSCL)是ITER Feeder PA(Procurement Agreement)中非常关键且具有挑战性的项目,严峻的工作条件以及严格的质量等级要求使得低温测试不可或缺,其出厂前的低温测试也为其验收交付提供强有力的数据保障.本文介绍了高温超导电流引线系列件低温性能测试控制系统的构成及实现,该系统基于CODAC(Control, Data Access and Communication)分布式系统搭建而成,整合了PLC子系统,QDS子系统,interlock互锁子系统,包含数据存贮(Archiving),报警Alarm,用户操作接口(OPI),应用开发SDD,及历史数据浏览(Data browsing)等子功能.实验结果表明,该系统具有控制和测量精度高、使用方便、运行稳定可靠、用户界面友好等优点.     

Efficiency decomposition in network data envelopment analysis: A relational model

Traditional studies in data envelopment analysis (DEA) view systems as a whole when measuring the efficiency, ignoring the operation of individual processes within a system. This paper builds a relational network DEA model, taking into account the interrelationship of the processes within the system, to measure the efficiency of the system and those of the processes at the same time. The system efficiency thus measured more properly represents the aggregate performance of the component processes. By introducing dummy processes, the original network system can be transformed into a series system where each stage in the series is of a parallel structure. Based on these series and parallel structures, the efficiency of the system is decomposed into the product of the efficiencies of the stages in the series and the inefficiency slack of each stage into the sum of the inefficiency slacks of its component processes connected in parallel. With efficiency decomposition, the process which causes the inefficient operation of the system can be identified for future improvement. An example of the non-life insurance industry in Taiwan illustrates the whole idea.     

Impact of information sharing and lead time on bullwhip effect and on-hand inventory

This work analyzes a two echelon (warehouse–retailer) serial supply chain to study the impact of information sharing (IS) and lead time on bullwhip effect and on-hand inventory. The customer demand at the retailer is assumed to be an autoregressive (AR(1)) process. Both the echelons use a minimum mean squared error (MMSE) model for forecasting lead time demand (LTD), and follow an adaptive base-stock inventory policy to determine their respective order quantities. For the cases of without IS and inter as well as intra echelon IS, expressions for the bullwhip effect and on-hand inventory for the warehouse are obtained, considering deterministic lead-time. The results are compared with the previous research work and an easy analysis of the various bullwhip effect expressions under different scenarios, is done to understand the impact of IS on the bullwhip effect phenomenon. It is shown that some part of bullwhip effect will always remain even after sharing both inter as well as intra echelon information. Further, with the help of a numerical example it is shown that the lead time reduction is more beneficial in comparison to the sharing of information in terms of reduction in the bullwhip effect phenomenon.     

基于ARMA(p,q)利息力生存年金精算现值模型

企业年金是养老保险体系的重要组成部分,其定价的合理性正受到越来越多的关注.主要是基于一般的ARM A(p,q)模型得到了随机利率下生存年金的精算现值模型,分别给出了年金给付的一阶矩和二阶矩,这对年金保险的合理收费和避免收不抵支情况的出现具有重要的指导意义.     

考虑结算风险的套期保值研究

期货市场的风险转移功能主要通过套期保值策略来实现,期货市场套期保值的关键问题是套期保值比率的确定。现有套期保值研究侧重于规避价格风险,忽略了期货市场另一个重要的风险因素-结算风险。本文通过建立考虑结算风险的期货套期保值决策模型,有效地平衡了套期保值过程中的价格风险与结算风险。具体特色一是将套保者的结算风险厌恶态度直接反映到套期比的计算中,体现了结算风险对套期保值决策的影响;二是在一定条件下,本模型的套期比趋近于最小方差套期比;三是利用ARMA时间序列方法预测期货与现货的价格走势,有效地反映了期货价格一阶平稳和季节性变化规律,使估计的套期比更加精确可靠。     

A modified Fourier series solution for vibration analysis of truncated conical shells with general boundary conditions

Free vibration analysis of truncated conical shells with general elastic boundary conditions is presented in this paper. An accurate modified Fourier series solution is developed, in which, regardless of the boundary conditions, each displacement of the conical shell is invariantly expressed as a new form of improved series expansions composed of a standard Fourier series and closed-form auxiliary functions introduced to ensure and accelerate the convergence of the series expansion. All the expansion coefficients are treated as the generalized coordinates and determined using the Rayleigh–Ritz method. By using the present method, conical shells with arbitrary boundary conditions including all classical and elastic end restraints can be solved in a unified form. The accuracy and convergence of the current approach are validated by numerical examples and comparison with FEM results and those from the literature, and excellent accuracy is demonstrated. Comprehensive studies on the effects of elastic restraint parameters, semi-vertex angle and the ratio of length to radius are also reported. Some new results are presented for cases with elastic boundary restraints which may serve as benchmark solution for future researches.     

ARMA模型在哈尔滨气温预测中的应用

将时间序列分析引入到气温时间序列预测的研究中,深入分析气温样本数据,并对其建立ARMA模型.采用最佳准则函数法确定模型的阶数,并利用自相关函数对模型的残差进行了检验.通过条件期望预测和适时修正预测方法求得预测值,与真实值的比较得到适时修正预测精确度比条件期望预测的精确度高.     

The effect of PVA (Bi2O3-doped) interfacial layer and series resistance on electrical characteristics of Au/n-Si (110) Schottky barrier diodes (SBDs)

Two types of Schottky Barrier Diodes (SBDs) with and without PVA (Bi₂O₃-doped) polymeric interfacial layer, were fabricated and measured at room temperature in order to investigate the effects of the PVA (Bi₂O₃-doped) interfacial layer on the main electrical parameters such as the ideality factor (n), zero-bias barrier height (Φ_B0), series resistance (R_s) and interface-state density (N_ss). Electrical parameters of these two diodes were calculated from the current-voltage (I-V) characteristics and compared with each other. The values of Φ_B0, n and R_s for SBDs without polymeric interfacial layer are 0.71 eV, 1.44 and 4775 Ω, respectively. The values of Φ_B0, n and R_s for SBDs with PVA (Bi₂O₃-doped) polymeric interfacial layer are 0.74 eV, 3.49 and 10,030 Ω, respectively. For two SBDs, the energy density distribution profiles of interface states (N_ss) were obtained from forward-bias I-V measurements by taking the bias dependence of R_s of these devices into account. The values of N_ss obtained for the SBD with PVA (Bi₂O₃-doped) polymeric interfacial layer are smaller than those of the SBD without polymeric interfacial layer.     

基于结构元线性生成的复Fuzzy值函数项级数

文献[1]中提出了基于结构元理论的Fuzzy数项级数的概念,文献[2]、文献[3]、文献[4]对其收敛性进行了探讨,文献[5]、文献[6]对模糊值函数项数列及级数进行了研究。本文在此基础上给出了基于结构元线性生成的复Fuzzy值函数项数列及级数的定义,同时对复Fuzzy值函数项级数的一些重要性质进行了研究,并给出了相应定理。