Coupled phase diagram and thermodynamic analysis of the 18 binary systems formed among Li2Co3, K2Co3,Na2Co3, Lioh, Koh, Naoh, Li2So4, K2So4 and Na2So4

Available phase diagram and thermodynamic data on the eighteen binary systems containing Li⁺ , Na⁺, K⁺, S0₄⁼, CO₃⁼, and OH⁻ have been collected and critically assessed. A set of self-consistent thermodynamic parameters describing the free energies of the compounds, solid solutions, and liquid solutions in the binary systems has been formulated. The phase diagrams have been calculated, and estimated error limits of all diagrams are given.     

基于多因素模糊推理的卫星综合效能评估

针对目前卫星复杂化、多任务、集群化发展大趋势,利用传统的性能穷举法及单性能评估法进行卫星的综合效能评估已经无法满足,对卫星综合效能指标体系进行研究,以微纳集群卫星为例,分层列举了相关指标体系,对卫星综合效能评估方法进行了研究,介绍了一般效能评估流程,提出了一种改进的模糊推理效能评估方法,该方法在原有单因素评估指标模糊推理的基础上,加入了指标间的多因素比较,并与层次分析相结合。最后以实际导航卫星为例进行仿真分析,分析结果表明该方法切实可行,效能评估结果正确有效,为复杂卫星系统提高其综合效能提供保障。     

单导心电监护中不同电极模式的自动识别方法

电极脱落、电极混用等不正常电极模式会影响采集的心电信号的质量,导致误诊。人工判断电极模式是否正常过于依赖人的经验。为此对单导心电采集中4种电极模式的自动识别方法进行研究,定义了表征不同电极模式的心电信号的数字特征,结合基于LDA的特征降维和最近邻分类器来实现自动识别。实验表明,所提出的自动识别方法对单导心电设备4种电极模式的自动识别有效,对电极脱落的正确识别率可达到100%。     

设计模式变体的描述与验证*

为解决标准设计模式演化后难以检测的问题,引入设计模式变体思想,以Bridge模式为例,给出了八种常用的变体实现,并以人工形式挖掘了四种开源系统中Bridge模式变体的基准数,接着在Apache Ant1.6.2与JHotDraw5.1开源系统中通过六种主流设计模式检测工具进行了变体检测实验。试验结果表明,FCA-CBR方法简单有效,对2种开源系统中Bridge模式变体检测的精确率达到60%与48.1%,与先前方法相比有了较大的提高。     

Preface: Volume 16, Issue 2

This volume contains the Proceedings of the fifth EXPRESS workshop. The workshop was held in Nice, France, on 7 September 1998, as a satellite event to CONCUR '98.The EXPRESS workshops aim at bringing together researchers interested in the relations between various formal systems, particularly in the field of Concurrency. More specifically, they focus on the comparison between programming concepts (such as concurrent, functional, imperative, logic and object-oriented programming) and between mathematical models of computation (such as process algebras, Petri nets, event structures, modal logics, rewrite systems etc.) on the basis of their relative expressive power.These workshops were originally held as meetings of the HCM project EXPRESS, which has been active with the same focus from January 1994 till December 1997. The first three workshops were held respectively in Amsterdam (1994, chaired by Frits Vaandrager), Tarquinia (1995, chaired by Rocco de Nicola), and Dagstuhl (1996, chaired by Ursula Goltz, Frits Vaandrager and Rocco de Nicola). The fourth workshop, which took place in Santa Margherita Ligure in 1997 and was co-chaired by Catuscia Palamidessi and Joachim Parrow, was organized as a conference with a call for papers and a significant attendance from outside the project. The fifth workshop, EXPRESS '98, was again organised as a (one day) conference, and was also meant as an occasion to discuss on the inheritance of the Express project and possible directions of future research. We had 17 submissions, out of which we selected 7 for inclusion in these proceedings (41%). Additionally, this collection contains the contribution of the two invited speakers, Matthew Hennessy (University of Sussex, UK) and P.S. Thiagarajan (SPIC Mathematical Institute, IN).We would like to thank the authors of the submitted papers, the invited speakers, and the members of the program committee for their contribution to both the meeting and this volume. We also would like to thank INRIA for their help with the local organization, and Michael Mislove for his help with the editing of the proceedings.

EXPRESS '98 Programme Committee
Ilaria Castellani (co-chair, INRIA)	Catuscia Palamidessi (co-chair, PSU)
Luca Aceto (Aalborg Univ.)	Roberto Amadio (Univ. Marseille)
Eike Best (Oldenburg Univ.)	Steve Brookes (CMU)
Philippe Darondeau (INRIA)	Rocco De Nicola (Univ. Firenze)
Jan Willem Klop (CWI)	Patrick Lincoln (SRI)
Frits Vaandrager (Nijmegen Univ.)	Glynn Winskel (Aarhus Univ.)

Full-size table

17 October 1998, Ilaria Castellani and Catuscia Palamidessi     

High aspect ratio In2O3 nanowires: Synthesis, mechanism and NO2 gas-sensing properties

Flexural In₂O₃ nanowires with high aspect ratios were synthesized via a hydrothermal–annealing route. The as-synthesized In₂O₃ nanowires had diameters of 30–50 nm and length up to several microns. Various reaction parameters, such as the kind of reagents, the time of hydrothermal treatment, annealing time and annealing temperature, were investigated by a series of control experiments. The as-synthesized In₂O₃ nanowires showed excellent gas-sensing properties to NO₂ in terms of sensor response and selectivity.     

Thermodynamic study of the KCl-K2SO4-K2Cr2O7-H2O system at the temperature 298.15 K

The Pitzerion-interaction model has been used for thermodynamic simulation of the ternary solutions KCl-K₂Cr₂O₇-H₂O, KBr-K₂Cr₂O₇-H₂O and K₂SO₄-K₂Cr₂O₇-H₂O and the quaternary system KCl-K₂SO₄-K₂Cr₂O₇-H₂O at T=298.15 K. The necessary thermodynamic functions (binary and ternary parameters of interionic interaction and thermodynamic solubility products) have been calculated and the theoretical solubility isotherms have been plotted. Good agreement between experimentally determined and calculated solubilities has been found.     

Experimental determination of the liquidus in the high basicity region in the Al2O3(30 mass%) - CaO - MgO - SiO2 system

The liquidus in the high basicity region in the Al₂O₃(30 mass%)-CaO-MgO-SiO₂ system were determined experimentally at 1773 and 1873 K using the quench technique followed by EPMA analysis. Based on the experimental data, a phase diagram of the Al₂O₃(30 mass%)-CaO-MgO-SiO₂(<20 mass%) section was constructed for 1773 and 1873 K. The solubilities of 2CaO.SiO₂ and 3CaO.SiO₂ at 1773 K were found to be considerably higher in comparison with the existing phase diagram. Even the solubility of MgO at 1873 K was found to be somewhat higher. In addition, the activities of MgO, CaO and Al₂O₃ at 1773 K were estimated using the phase diagram information.     

Object-oriented design patterns in Fortran 90/95: mazev1, mazev2 and mazev3

This paper discusses the concept, application, and usefulness of software design patterns for scientific programming in Fortran 90/95. An example from the discipline of object-oriented design patterns, that of a game based on navigation through a maze, is used to describe how some important patterns can be implemented in Fortran 90/95 and how the progressive introduction of design patterns can usefully restructure Fortran software as it evolves. This example is complemented by a discussion of how design patterns have been used in a real-life simulation of Particle-in-Cell plasma physics. The following patterns are mentioned in this paper: Factory, Strategy, Template, Abstract Factory and Facade.

Program summary

Program title: mazev1, mazev2, mazev3Catalogue identifier: AEAI_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAI_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 1958No. of bytes in distributed program, including test data, etc.: 17 100Distribution format: tar.gzProgramming language: Fortran 95Computer: PC/MacOperating system: Unix/Linux/Mac (FreeBSD)/Windows (Cygwin)RAM: These are interactive programs with small (KB) memory requirementsClassification: 6.5, 20Nature of problem: A sequence of programs which demonstrate the use of object oriented design patterns for the restructuring of Fortran 90/95 software. The programs implement a simple maze game similar to that described in [1].Solution method: Restructuring uses versions of the Template, Strategy and Factory design patterns.Running time: Interactive.References:

[1] 

E. Gamma, R. Helm, R. Johnson, J. Vlissides, Design Patterns: Elements of Reusable Object Oriented Software, Addison-Wesley, 1995, ISBN 0201633612.

     

Electrical response of Sm2O3-doped SnO2 to C2H2 and effect of humidity interference

Pure and Sm₂O₃-doped SnO₂ are prepared through a sol–gel method and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The sensor based on 6 wt% Sm₂O₃-doped SnO₂ displays superior response at an operating temperature of 180 °C, and the response magnitude to 1000 ppm C₂H₂ can reach 63.8, which is 16.8 times larger than that of pure SnO₂. This sensor also shows high sensitivity under various humidity conditions. These results make our product be a good candidate in fabricating C₂H₂ sensors.     

A route to high sensitivity and rapid response Nb2O5-based gas sensors: TiO2 doping, surface embossing, and voltage optimization

We report a novel route for the fabrication of highly sensitive and rapidly responding Nb₂O₅-based thin film gas sensors. TiO₂ doping of Nb₂O₅ films is carried out by co-sputtering without the formation of secondary phases and the surface area of TiO₂-doped Nb₂O₅ films is increased via the use of colloidal templates composed of sacrificial polystyrene beads. The gas sensitivity of Nb₂O₅ films is enhanced through both the TiO₂ doping and the surface embossing. An additional enhancement on the gas sensitivity is obtained by the optimization of the bias voltage applied between interdigitated electrodes beneath Nb₂O₅-based film. More excitingly, such a voltage optimization leads to a substantial decrease in response time. Upon exposure to 50 ppm CO at 350 °C, a gas sensor based on TiO₂-doped Nb₂O₅ film with embossed surface morphology exhibits a very high sensitivity of 475% change in resistance and a rapid response time of 8 s under 3 V, whereas a sensor based on plain Nb₂O₅ film shows a 70% resistance change and a response time of 65 s under 1 V. Thermal stability tests of our Nb₂O₅-based sensor reveal excellent reliability which is of particular importance for application as resistive sensors for a variety gases.     

First-principles calculations of the YBa2Cu3O7/PrBa2Cu3O7 interface

We discuss results of spin-polarized electronic structure calculations for a 1 × 1 YBa₂Cu₃O₇/PrBa₂Cu₃O₇ supercell, obtained by the full-potential linear augmented plane wave (FLAPW) method as implemented in the WIEN2k package. The calculations are based on the generalized gradient approximation for the exchange correlation functional. The on-site Coulomb interaction of the correlated Cu 3d and Pr 4f electrons is considered by using the LSDA+U approach. The electronic states of the YBa₂Cu₃O₇/PrBa₂Cu₃O₇ interface are compared with the respective states in the PrBa₂Cu₃O₇ and YBa₂Cu₃O₇ bulk compounds, where we focus on the magnetic Pr atoms and the Cu atoms in the CuO₂ planes.     

Solid-state potentiometric SO2 sensor combining NASICON with V2O5-doped TiO2 electrode

A compact tubular sensor based on NASICON (sodium super ionic conductor) and V₂O₅-doped TiO₂ sensing electrode was designed for the detection of SO₂. In order to reduce the size of the sensor, a thick-film of NASICON was formed on the outer surface of a small Al₂O₃ tube; furthermore, a thin layer of V₂O₅-doped TiO₂ with nanometer size was attached on the NASICON as a sensing electrode. This paper investigated the influence of V₂O₅ doping and sintering temperature on the characteristics of the sensor. The sensor attached with 5 wt% V₂O₅-doped TiO₂ sintered at 600 °C exhibited excellent sensing properties to 1–50 ppm SO₂ in air at 200–400 °C. The EMF value of the sensor was almost proportional to the logarithm of SO₂ concentration and the sensitivity (slope) was −78 mV/decade at 300 °C. It was also seen that the sensor showed a good selectivity to SO₂ against NO, NO₂, CH₄, CO, NH₃ and CO₂. Moreover, the sensor had speedy response kinetics to SO₂ too, the 90% response time to 50 ppm SO₂ was 10 s, and the recovery time was 35 s. On the basis of XPS analysis for the SO₂-adsorbed sensing electrode, a sensing mechanism involving the mixed potential at the sensing electrode was proposed.     

H2 sensors using Fe2O3-based thin film

This paper describes the fabrication procedure as well as the sensing properties of new hydrogen sensors using Fe₂O₃-based thin film. The film is deposited by the r.f. sputtering technique; its composition is Fe₂O₃, TiO₂(5 mol%) and MgO(0–12 mol%). The conductance change of the film is examined in various test gases. The sensitivity to hydrogen gas is enhanced by treating the film in vacuum at 550 °C for 4 h and then in air at 700 °C for 2 h. The sputtered film is identified to be polycrystalline -Fe₂O₃ based on X-ray diffraction patterns. However, the surface layer is considered to be changed to Fe₃O₄ after heating in vacuum and then to γ-Fe₂O₃ after heating in air. The film is thus a multilayer one with a thin γ-Fe₂O₃ layer on a -Fe₂O₃ layer. The sensing mechanism is discussed based on measurements of the physical properties of the film, such as the temperature dependence of the sensor conductance, X-ray diffraction pattern, surface morphology, RBS (Rutherford back-scattering) spectrum and optical absorption spectrum.     

Temperature dependent H2S and Cl2 sensing selectivity of Cr2O3 thin films

The conductometric gas sensing characteristics of Cr₂O₃ thin films - prepared by electron-beam deposition of Cr films on quartz substrate followed by oxygen annealing - have been investigated for a host of gases (CH₄, CO, NO₂, Cl₂, NH₃ and H₂S) as a function of operating temperature (between 30 and 300 °C) and gas concentration (1-30 ppm). We demonstrate that these films are highly selective to H₂S at an operating temperature of 100 °C, while at 220 °C the films become selective to Cl₂. This result has been explained on the basis of depletion of chemisorbed oxygen from the surface of films due to temperature and/or interaction with Cl₂/H₂S, which is supported experimentally by carrying out the work function measurements using Kelvin probe method. The temperature dependent selectivity of Cr₂O₃ thin films provides a flexibility to use same film for the sensing of Cl₂ as well as H₂S.     

基于视情维修的涡轴发动机维修保障辅助决策体系研究

复杂装备科学的维修保障策略是保证装备合理使用与适时修理的基础,是有效实施复杂装备全寿命保障的前提,关系着装备任务效能的有效发挥;文中立足于航空装备的视情维修策略,以直升机中广泛采用的涡轴发动机为研究对象,首先基于装备维保过程的大量信息提出了构建涡轴发动机涡轴发动机及其关键部件寿命与健康管理综合知识库的方法、策略;其后结合涡轴发动机循环寿命统计法与基于K均值聚类算法等各类使用条件下的寿命损耗研究方法,阐明了涡轴发动机不同应用条件下的备件量化分析策略;更进一步地,以涡轴发动机关键部件典型故障模式梳理与成因分析(FMECA)与考虑故障概率的发动机核心备件的量化分析为基础,给出了涡轴发动机关键部件备件量化方法与策略;最后基于上述方法的研究成果,阐述了涡轴发动机维修保障辅助决策软件平台的体系架构;文中的相关研究成果可被用于航空发动机等复杂装备系统的维修保障策略构建与工程化应用.