分析化学实验成绩评定软件的开发

介绍了分析化学实验成绩评定软件的主要内容、设计思想及功能 ,该软件采用VisualFoxPro5 0中文版编程 ,可用于分析化学实验成绩的评定。内容包括 :实验数据输入、实验数据修改、实验数据处理、实验结果查询、实验数据打印、修改学生名单等。本软件具有操作简单、使用方便等特点     

佩戴式虚拟现实技术

佩戴式虚拟现实系统可以让用户带着计算机进入真实世界 ,所以它对诸如医生、军人、消防队员等有着非常多的应用。本文介绍了佩戴式虚拟现实系统的概念、应用和产品 ,重点阐述了佩戴式虚拟现实系统的构成和关键技术     

Syntax-driven Behavior Partitioning for Model-checking of Esterel Programs

We consider the issue of exploiting the structural form of Esterel programs to partition the algorithmic RSS (reachable state space) fix-point construction used in model-checking techniques. The basic idea sounds utterly simple, as seen on the case of sequential composition: in P; Q, first compute entirely the states reached in P, and then only carry on to Q, each time using only the relevant transition relation part. Here a brute-force symbolic breadth-first search would have mixed the exploration of P and Q instead, in case P had different behaviors of various lengths, and that would result in irregular BBD representation of temporary state spaces, a major cause of complexity in symbolic model-checking.Difficulties appear in our decomposition approach when scheduling the different transition parts in presence of parallelism and local signal exchanges. Program blocks (or “Macro-states”) put in parallel can be synchronized in various ways, due to dynamic behaviors, and considering all possibilities may lead to an excessive division complexity. The goal is here to find a satisfactory trade-off between compositional and global approaches. Concretely we use some of the features of the TiGeR BDD library, and heuristic orderings between internal signals, to have the transition relation progress through the program behaviors to get the same effect as a global RSS computation, but with much more localized transition applications. We provide concrete benchmarks showing the usefulness of the approach.     

基于网络的三维数字化信息家电产品定制系统研究与实现*

从满足客户多样化的需求出发,针对信息家电的特点,深入研究了基于网络的大规模定制的 理论与方法,开发了一个基于网络的三维数字化信息家电产品定制系统。该系统简洁直观, 方便易用,能够有效获取客户需求信息,满足客户的个性化定制需要。     

分级移动IPv6中一种新的自适应MAP选择算法*

分级移动IPv6中存在单点故障和负荷集中问题。提出一种基于分布式MAP结构的自适应MAP选择算法,综合考虑移动节点的当前速度、会话到达率、MAP负荷及距离等因素,以MN注册后将产生的移动性管理信令开销最小为依据进行选择。仿真结果表明,自适应MAP选择算法能够根据移动节点和网络的当前特性优化地选择不同的MAP进行注册,使移动性管理信令开销最小,具有较好的负荷分担效果,并一定程度上增强了分级结构的鲁棒性。与最远/近MAP选择方案相比,自适应MAP选择算法能够提高网络的吞吐量及减少平均切换时延。     

Modulation of the mitochondrial cyclosporin A-sensitive permeability transition pore. I. Evidence for two separate Me2+ binding sites with opposing effects on the pore open probability

This paper reports an investigation on the regulation of the mitochondrial cyclosporin A-sensitive permeability transition pore (MTP). Energized, coupled rat liver mitochondria incubated in sucrose medium in the presence of phosphate maintain a high proton electrochemical gradient (delta microH) and a low permeability to solutes. Addition of a small (10-20 microM) Ca2+ pulse leads to a transient membrane depolarization. After Ca2+ accumulation, a high delta microH is recovered, and mitochondria remain coupled indefinitely. Yet, addition of fully uncoupling concentrations of carbonyl cyanide-p-trifluoromethoxyphenyl hydrazone (FCCP) brings about MTP opening within seconds. This finding confirms that MTP opening is the consequence rather than the cause of membrane depolarization, and allowed us to study the operation of the MTP in a synchronized population of mitochondria, since pore opening can be triggered by the addition of uncoupler under a series of experimental conditions. We find that three regulatory sites can be defined: (i) an internal Me2+ binding site: when this site is occupied by Ca2+, the pore "open" probability increases, while other Me2+ ions (Sr2+, Mn2+) have an inhibitory effect; (ii) an external Me2+ binding site: when this site is occupied by Me2+ ions, including Ca2+, the pore open probability decreases; (iii) an independent cyclosporin A binding site: when this site is occupied by cyclosporin A the pore open probability decreases. We show that at variance from the case of cyclosporin A, MTP inhibition by the phospholipase A2 inhibitors nupercaine and trifluoperazine is Ca(2+)-competitive and is presumably related to interference by these drugs with Ca2+ binding to the internal regulatory site.     

TeO2 bolometers to search for Double Beta Decay of130Te: status of art

A 334g TeO₂ crystal is operating since January '93 at Gran Sasso National Laboratories as a thermal detector to search for neutrinoless decay of¹³⁰Te. The reduction of environmental radioactivity is accomplished by means of a 10 cm thick external lead shielding and a plexiglas box against²²²Rn, while an inner ultra-low activity lead shield of at least 3.5 cm in every direction suppresses the residual local radioactivity near the crystal. The good energy resolution and the peak-to-Compton efficiency of the detector allow to understand the main features of the residual background. In particular, we are able to reach a sensitivity in the internal contamination of²³⁸U and²³²Th of the crystal of the order of 10^–13 g/g, better than that of modern mass spectroscopy methods. Pulse acquisition and analysis techniques are reported and discussed.Present limit on neutrinoless decay half-life time of¹³⁰Te obtained with this detector is of the order of 10²²y at 68% C.L., exceeding by one order of magnitude the value quoted by the inclusive geochemical measurements, which have therefore to be attributed mainly to the 2-neutrino channel.On leave from the Dept. of Physics, University of Zaragoza     

The indent reflow sealing (IRS) technique-a method for thefabrication of sealed cavities for MEMS devices

A variety of microelectromechanical system devices requires encapsulation of their crucial fragile parts in a hermetically sealed cavity for reasons of protection. Hermeticity of the cavity and controllability of the ambient (gas pressure and gas composition) can be critical to the device performance. In order to minimize damage during handling, the cavity is preferably realized at the same time the device is fabricated, i.e., at wafer level. This paper reports the development of a hermetic packaging technique satisfying all the above. The method is referred to as the indent-reflow-sealing (IRS) technique, which relies on a multiple-chip fluxless solder-based joining technique and seal. Key process steps are the creation of an indent in the solder, the plasma pretreatment of the bonding surfaces, the pre-bonding (or sticking) of the chips and, the closing of the indent during a low-temperature (220°C-350°C) solder reflow in a clean controlled ambient using a designated oven. As opposed to other methods, the IRS method allows a greater flexibility with respect to the choice of the sealing gas and pressure, thereby offering a very hermetic seal and compatibility with low-cost high-throughput batch fabrication techniques. Flip-chip assemblies based on SnPb (67/37) solder and Au as the top surface metallization, have been reflowed in a forming gas ambient and have next been characterized on shear strength, hermeticity, and susceptibility to thermal stresses. The method has been successfully implemented in the process flow of an electromagnetic microrelay for the realization of the cavity housing the electrical contacts     

Définition théorique des paramètres en fort niveau d’un multipôle actif non linéaire

In this paper, large signal non linear P parameters are rigorously defined, allowing the characterization of non linear active n-port circuits in the frequency domain with the aim of computer aided design of power microwave devices. No a priori conditions bind the parameters to the variables describing the input signal. However the following rules apply to the parameters: they may be function of any input variables of the n-port circuit; the expression of the large-signal parameters should become identical to the expression of the linear parameters characterizing the n-port circuit under linear operating conditions when the values of the input variables tend to zero. An application of the definition to afet is demonstrated.     

Two-dimensional pressure-temperature phase diagram and latent heats of neon adsorbed on exfoliated graphite

A two-dimensional pressure-temperature phase diagram was constructed for neon adsorbed on exfoliated graphite using the heat capacity data obtained in our laboratory for this system. The two-dimensional pressures at the triple and critical points were found to be _t=64×10^–6 N/m and _c=128×10^–6 N/m, respectively. From Clapeyron's equation and assuming an ideal behavior for the two-dimensional gas phase, the latent heat of sublimation was calculated as a function of temperature. The latent heat of vaporization was also calculated at the triple point and consequently the latent heat of fusion was found. The following values were obtained at the triple point:l _s/k=86 K,l _v/k=24 K, andl _f/k=62 K.