Construction of approximations for scientific and technical calculations

Methods of constructing approximations for technical applications are outlined.     

The scientific and technical foundations of electromagnetic isotope separation technology

The physical basis, and development, of the electromagnetic isotope separation method are briefly surveyed and compared with other isotope separation techniques used. The main componental stages of the electromagnetic isotope separation technology, namely the ion production, ion beam transport and isotope collection are described and physical and technical backgrounds for constructional and operational characteristics of separators are discussed.     

Spanish scientific and technical journals. State of the art

This article analyses the current situation in the field of scientific and technical journals published in Spain, by determining the following scientific indicators for each: I: Specifications. II: Scientific production covered. III: Visibility and accessibility. The first section provides a qualitative and quantitative study of the journals, asking what subjects they cover, who publishes them, how often they are published, how up to data they are and whether the way they are presented meets international publishing standards. The second section analyses scientific production by research sectors and the percentage of articles collected in the ICYT database compared with the total number of papers published in the journals studied. It also studies the reference habits of the authors published therein to identify whether the literature referred to is of local origin or international. Finally, the third section deduces these journals' degree of visibility by analysing how they are distributed amongst the usual media, i.e. international periodicals directories and databases, and how efficiently they work as vehicles for the diffusion of research by foreign authors. The study covers 10 years (1980–1989), thus enabling to recognise past and current trends in Spanish scientific literature.     

Size,age and productivity of scientific and technical research groups

Varied empirical studies show that the average output (measured in various ways) of a scientific or technical research group is directly proportional to its size (also measured in various ways), when the size and output are measured independently. Hence groups of different sizes have the same average output per unit of size. There is no reliable evidence for the existence of a size or a range of sizes for a research group that maximizes output per unit of size. Present theoretical explanations for the proportionality between size and output are largely inadequate or untested. Similarly, among reported results on group age and output, the only consistency so far is that age, measured as years since the founding or first functioning of the group, is uncorrelated with output per capita. Again, there is no evidence for the existence of an age or a range of ages for a research group that is optimal.This paper was prepared for the conference on Generational Dynamics and Innovation in Basic Science, June 1–2, 1989, organized byKarl Urlich Mayer, and held at the Max-Planck-Gesellschaft zur Förderung der Wissenschaften, Schloß Ringberg, Tegernsee, B. R. D. (West Germany). A German translation of this article has been published in theMitteilungen der Max-Planck-Gesellschaft, Heft 3/90.     

标准化是发展清洁汽车的技术保障

标准化是国民经济和社会发展中一项重要的技术基础工作,当然也是推动我国汽车工业发展和技术进步不可缺少的一项重要工作,是发展我国清洁汽车的技术保障.近10年来,随着汽车保有量的增加,世界各国对环境保护和节约能源的呼声越来越高.欧洲、美国、日本等发达国家相继推出了电动汽车和燃气汽车产品,同时国际标准化组织(IS0)和国外工业发达国家相应地颁布了一些标准和技术法规.