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研究燃料汽车及其氢源系统是当今国内外能源工业与汽车工业的共同课题，而优选制氢能源则是这一课题的关键。章介绍了利用能源、经济、环境(EEE)——生命周期评估(LCA)这一综合评估方法，针对以天然气、煤或石油作为制氢能源的多种燃料电池氢源供应方式以及配套的燃料电池汽车系统，从经济性、能源利用效率和环境影响三个方面进行了生命周期清单分析和EEE综合评价。结果显示：天然气作为发展燃料电池汽车氢源的一次能源，具有氢制取技术路线多样化、经济上竞争力强、能源利用效率高和环境效益好等诸多优势，应为燃料电池汽车的首选制氢能源。对这一评估模型的敏感性分析显示，即使在天然气价格波动较大时，天然气制甲醇--甲醇车载重整车和天然气制氢--纯氢车这两个方案仍然最具优势。     

Numerical simulation of developing natural convection in an enclosure due to rapid heating

Effects of thermoacoustic wave motion on the developing natural convection process in a compressible gas-filled square enclosure were investigated numerically. In the cases considered, the left wall temperature is raised rapidly (impulsively or gradually) while the right wall is held at a specified temperature. The top and the bottom walls of the enclosure considered are thermally insulated. The numerical solutions of the full Navier-Stokes equations were obtained by employing a highly accurate flux-corrected transport algorithm for the convection terms and by a central differencing scheme for the viscous and diffusive terms. The strength of the pressure waves associated with the thermoacoustic effect and resulting flow patterns are found to be strongly correlated to the rapidity of the wall heating process. Fluid thermal diffusivity was found to affect the strength of the thermoacoustic waves and the resulting interaction with the buoyancy-induced flow.     

Twenty-five years of natural coordinates

In the early eighties, the author and co-workers created and further developed the natural coordinates to describe the motion of 2-D and 3-D multibody systems. Natural coordinates do not need angles or angular parameters to define orientation, leading to constant inertia matrices and to the simplest form of the constraint equations. Natural coordinates are composed by the Cartesian coordinates of some points and the Cartesian components of some unit vectors distributed on the different bodies of the system. The points and vectors can be located in the joints, being shared by contiguous bodies, decreasing or even eliminating the need to set joint constraints and reducing the total number of variables. However, other authors prefer not to share variables in order to get even simpler equations and to keep a bigger decoupling of equations, which is preferable in some cases. In this paper the history of natural coordinates is reviewed, as well as the main contributions coming from other research groups. In the second part of the paper some application areas in which natural coordinates can be particularly advantageous are examined. Commemorative Contribution.     

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对三种天然气压缩因子计算方法：经典热力学法、SGERG-88法、SY／T6143—1996法进行了介绍并对计算结果进行了对比，第一种方法的计算精度远不能满足贸易结算的要求，我国现行的第二种计算方法与ISO标准方法相比，在10℃以上的温度范围内基本相符，但在10℃以下的低温段则偏差较大。由此说明，我国目前所实施的计量标准与国际上认可的ISO标准方法之间有较大的偏差；同时，对不需要在线计算的场合，提出了一套基于数据拟合的计算体积修正系数的高精度近似方法，可提高体积计量仪表的性价比。     

实用天然气可采储量标定软件的开发及应用

针对天然气的开发特点，优选出了方便实用的可采储量标定方法。以气田开发数据库为基础，采用面向对象的程序设计语言VC＋＋，编制了可采储量标定软件，该软件集数据处理、物性参数计算、可采储量标定、结果输出4个模块为一体，计算快捷、迅速、准确，运行稳定、安全、可靠，提高了天然气可采储量标定的精度和工作效率。     

某厂锆（Zr）生产流程中不同产物的天然放射性核素含量测定

本文报道了某厂锆(Zr)生产流程中原料(锆英砂,主要成份为 ZrSiO_4)、半成品(ZrC,ZrCl_4)、废渣和成品锆中天然放射性核素~(238)U、~(226)Ra、~(232)Th 和~(40)K 含量测定结果。采用 NaI(Tl)γ能谱法进行测定,结果表明,原料、半成品和废渣中都含有一定的放射性,各生产环节应采取适当的防护措施;成品锆中基本不含放射性,可安全地应用于各个生产和生活领域。     

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日本政府采取一整套行之有效的政策措施来促进天然气消费，这套政策措施是：以立法的形式促进天然气消费，大力发展燃气企业，支持与鼓励天然气发电，大力发展燃气空调，支持和资助天然气实用技术的开发，以各种方式会同各家公司建立某些机构促进日本天然气产业的发展，采取财政信贷措施支持天然气的进口。对我国的启示是：建立和完善与天然气相关约法律法规体系，成立一些中介机构，鼓励开拓天然气利用的新途径，采取优惠措施鼓励居民使用天然气，同时政府应积极参与和支持新技术的研究、开发、应用和推广。     

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由于天然气输气管线埋在地下，在通球清管过程中，球的运行情况不能直接观察，管线入口和出口压力在球运行过程中的变化也不能提前预测，也难准确控制进气量，使球能以１ｍ／ｓ的速度到达出口，为此进行了天然气输气管线清管通球计算机仿真系统的设计与实现的研制。该仿真系统是在深入分析和研究天然气输气管线清管通球运行规律的影响因素的基础上，以数据库管理、计算机仿真技术和人工智能等新技术为主要工具来开发的。着重介绍了该仿真系统的总体结构与功能设计，软件编程与调试。该仿真系统能真实仿真清管球在管线内运行，通过对靖边—榆林输气管线多次清管通球的运行过程实际模拟，其符合率在９３％以上。     

Combining natural language with direct manipulation: the conceptual framework for a hybrid human-computer interface

This paper describes the development of a conceptual model of an interaction system for future human-computer interaction. It is suggested that an integrated system is the most promising solution for diverse users and tasks. A ' hybrid interaction system' is considered, which tries to efficiently direct manipulation, menu selection, and natural language. The mechanism of the natural language interface module is described in more detail. Finally, the allocation of functionalities for generalized tasks on the conceptual model is considered from the taxonomic approach.     

GEOCHEMICAL CHARACTERISTICS OF THE COAL－FORMED GASES IH THE EAST OF THE CENTRAL－ASIA COAL－FORMED GAS ACCUMULATION DOMAIN──SERIES STUDY Ⅱ ON THE CENTRAL－ASIA COAL－FORMED GAS ACCUMULATION DOMAIN

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