Experimental Determination of Isobaric Heat Capacities of R227 (CF<Subscript>3</Subscript>CHFCF<Subscript>3</Subscript>) from 223 to 283 K at Pressures up to 20 MPa.

A new experimental method for measuring isobaric heat capacity c_p down to 223 K at pressures up to 30 MPa was developed with the aim to study alternative refrigerants at sub-ambient temperatures and elevated pressures. The experiments are carried out in a batch mode, using a differential fluxmetric calorimeter Setaram BT-215, equipped with a customized high-pressure unit. The measurements are performed at constant pressure with a continuous scan of temperature. First, the method was tested at atmospheric pressure with methanol in the temperature range 223–283 K. The relative deviation from recommended isobaric heat capacity data in the literature is about 0.5%. Second, the measurements were performed at pressure up to 18.2 MPa with an alternative refrigerant R134a (1,1,1,2-tetrafluoroethane) of well-known heat capacity. Our results agree with representative literature values within 0.4%. New original results were obtained for refrigerant R227 (1,1,1,2,3,3,3-heptafluoropropane) in the temperature range from 223 to 283 K and at pressures of 1.1, 5, 10, 15, and 20 MPa. The consistency of our isobaric heat capacities with calorimetric values above 273 K and with pVT data reported in the literature is discussed.     

燃料电池用新型质子交换膜的研究进展

质子交换膜燃料电池(PEMFC)以其高效、清洁、高能量密度和高功率密度等诸多优点正引起人们越来越多的关注和研究．目前,质子交换膜是制约PEMFC技术应用的一个主要问题．为此,开发性能良好、成本经济的新型质子交换膜是一项很有意义的工作、综述了近几年国内外在新型质子交换膜(包括全氟磺酸膜、部分含氟磺酸膜、非氟质子交换膜)方面的研究进展．     

Numerical Study on Effects of Fuel Mixture Fraction and Li-6 Enrichment on Neutronic Parameters of a Fusion–Fission Hybrid Reactor

This study presents the effects of mixture fractions of nuclear fuels (mixture of fissile–fertile fuels and mixture of two different fertile fuels) and ⁶Li enrichment on the neutronic parameters (the tritium breeding ratio, TBR, the fission rate, FR, the energy multiplication ratio, M, the fissile breeding rate, FBR, the neutron leakage out of blanket, L, and the peak-to-average fission power density ratio, Γ) of a deuterium–tritium (D–T) fusion neutron-driven hybrid blanket. Three different fertile fuels (²³²Th, ²³⁸U and ²⁴⁴Cm), and one fissile fuel (²³⁵U) were selected as the nuclear fuel. Two different coolants (pressurized helium and natural lithium) were used for the nuclear heat transfer out of the fuel zone (FZ). The Boltzmann transport equation was solved numerically for obtaining the neutronic parameters with the help of the neutron transport code XSDRNPM/SCALE4.4a. In addition, these calculations were performed by also using the MCNP4B code. The sub-limits of the mixture fractions and ⁶Li enrichment were determined for the tritium self-sufficiency. The considered hybrid reactor can be operated in a self-sufficiency mode in the cases with the fuel mixtures mixed with a fraction of equal to or greater than these sub-limits. Furthermore, the numerical results show that the fissile fuel breeding and fission potentials of the blankets with the helium coolant are higher than with the lithium coolant.     

斯德哥尔摩高放废物地质处置库国际大会概况

本文对2003年12月在瑞典斯德哥尔摩召开的“地质处置库国际大会：政治和技术进展”会议内容进行了简要小结。这次会议介绍了过去4年中有关国家地质处置计划取得的进展、目前面临的挑战和今后的规划;还对中国高放废物地质处置工作提出了政策、法规、管理体制、长远规划、经费、国际合作以及公众接受等方面的建议。     

汽车发动机用氧传感器的研究

发动机尾气在排出之前要利用三元催化剂对有害成分进行催化处理。其净化率与尾气中的氧含量有关,同时配合节能,通过氧气含量的测定,可实时控制A/F即空燃比(气缸内空气与燃料的混合比例),确保缸内燃料充分燃烧,以尽可能减少尾气中有害气体的含量,由此便可利用氧传感器。文章描述了ZrO2氧传感器的发展现状,介绍了它的结构、工作原理和应用,以及新型稳定剂的添加等关键技术。     

An overview of a nuclear reprocessing plant Human Factors programme

This paper presents a case study of a large Human Factors programme applied in the nuclear fuel reprocessing industry (1987-1991). The paper outlines the key Human Factors issues addressed, as well as the impacts achieved, and gives an indication of the resources utilised (approximately 15 person-years of effort). It also considers the starting point of the programme, in terms of the factors that led to the need for such an extensive programme. Some general lessons learned are given at the end of the paper.     

美军在着火安全燃料方面的研究与应用

介绍了美军在着火安全燃料技术方面的研究与应用,包括燃料性能的调整、改型燃料的研究及首火防护与控制等。     

The conductivity of co-dopant ceria electrolyte

1　IntroductionManyresearchersaregraduallyinterestedinceriaelectrolytesfortheiroutstandingmerits ,especiallyinin termediatetemperaturesolidoxidefuelcell (IT -SOFC) .InIT -SOFCfield ,anode supportedplanarstackisbe comingthemainstream .Therefore ,mechanicalpropertiesofelectrolytesarenolongerimportantfordesiredperfor mance ,andthemainattentionfocusesonhowtoimprovetheionicconductivity .Themainaimsofimprovingtheionicconductivityaretomakethinnerfilmanddevelopnewelectrolyteseriesandco dopantsadd…     

Electrodes modified by electrodeposition of CoTAA complexes as selective oxygen cathodes in a direct methanol fuel cell

The oxygen reduction reaction (ORR) at cobalt tetraazaanulene (CoTAA) modified electrodes was investigated. As a first approach, modified electrodes were prepared by electrodeposition of CoTAA on glassy carbon (GC). The modification of the GC surface was monitored by u.v.–vis. differential reflectance spectroscopy (UVDRS). The recorded spectra (i.e., absorbance as a function of wavelength and time) showed that the electrodeposition of CoTAA at 0.8 V vs Ag|AgCl, that is, at a potential where the TAA ligand is oxidized to TAA⁺, seems to produce a thin polymer film. Starting from these preliminary results, porous rotating disc electrodes (RDEs) were prepared by electrodeposition of CoTAA (0.8 V vs Ag|AgCl, 1 min) on graphite powder embedded in a recast Nafion^® film. The use of a porous RDE allowed comparison of the activity and selectivity of Pt nanoparticles and CoTAA for the ORR under experimental conditions close to those of a fuel cell cathode, that is, at the catalyst|Nafion^® interface. The activity towards the ORR of a porous electrode modified by electrodeposition of CoTAA is not affected when methanol is present in the electrolyte phase, whereas a noticeable decrease in the activity of Pt-based oxygen cathodes was observed under the same conditions. Half-cell life tests showed that CoTAA-modified electrodes and Pt-based electrodes have a comparable stability over a period of 90 min.     

An Evaluation of the International Maritime Organization's Gaseous Agents Test Protocol

The International Maritime Organization (IMO) Maritime Safety Committee's (MSC) subcommittee on fire protection (FP) has developed a test protocol for evaluating the extinguishing effectiveness and critical design parameters of fixed gaseous halon alternative fire extinguishing systems. This paper is an evaluation of the developed protocol based upon its effectiveness in verifying agent distribution throughout the protected space and the effectiveness of the agent against typical maritime fire scenarios. The testing described herein was conducted by the U.S. Coast Guard as part of their evaluation of the developed protocol. Four halocarbon agents (NAF-SIII, CEA-410, CEA-308 and FM-200), one inert agent (Inergen), one gas/powder mix (Envirogel), and Halon 1301 for baseline comparisons were evaluated with the protocol. The IMO Protocol was found to represent a reasonable basis for evaluating the effectiveness of fixed gaseous fire extinguishing systems. However, the results from testing with the protocol are subject to interpretation due to the lack of a definition of the end of the discharge time. The four fire scenarios that make up the protocol can better meet their respective objectives by modifying the scenarios to reduce the impact on extinguishment of variables other than the uniform addition of agent throughout the space (e.g., oxygen depletion, localized high agent concentrations, and localized high flow velocities).