试论高校技术开发系统内部运行机制的构建与完善

本文论述了技术开发工作在高校自我发展中的地位与作用，进而确定了高校开展技术开发活动的要素条件，在分析阻碍高校开展技术开发工作内部症结问题的基础上，初步建立了由整合机制、动力机制、导向机制、调控机制和发展机制等五部分构成的良性高校技术开发系统内部运行机制。     

Small-group searches for mathematical proofs and individual reconstructions of mathematical concepts

This is a study of mathematics students working in small groups. Our research methodology allows us to examine how individual ideas develop in a social context. The research perspective used in this study is based on a co-constructive view of learning. Groups of three or four undergraduate mathematics majors, with prior experience writing mathematical proofs together, were asked to prove three statements. Computer software, such as Geometers Sketchpad, was available. Group work sessions were videotaped. Later, individuals viewed segments of the group video and were asked to reflect on group activities. Students in some groups did not share a common conception of proof, which seemed to hamper their collaboration. We observed interactions that fit with the co-constructive theory, with bidirectional interactions that shaped both group and individual conceptions of the tasks. These changes in understanding may result from parallel and successive internalization and externalization of ideas by individuals in a social context.     

Numerical analysis of fatigue striations

A computational model was developed to numerically analyse fatigue striations. The inclined strip yield model with continuous distributions of infinitesimal dislocations was utilized to express the crack tip plasticity in this model. The fatigue crack tip blunting process was approximated by sequential activation of two slip lines under loading, and crack closure during unloading was taken into account. The plastic zone at a growing fatigue crack tip at the maximum load was independent of the crack growth up to ten cycles while the reversed plastic zone decreased in a size to one twentieth of that at the maximum load as the crack grew. The ratio of these plastic zone sizes and also the crack tip opening displacement were quite different from the simple prediction by J.R. Rice for a stationary crack. The computed striation spacings were compared with the observed ones and moderate agreement between them obtained.     

The Visual/Kinesthetic Effects of Melodic Contour in Musical Notation as it Affects Vocal Timbre in Singers of Classical and Music Theater Repertoire

The purpose of this investigation was to obtain information from professional singers active in performing of both classical and music theater repertoire with regard to the visual/kinesthetic effect of melodic contour in musical notation as it affects vocal timbre. The evaluation of data gathered during the study indicates that there is reason to investigate the resulting postural shifts of the head and neck because they are guided by visual maps of melodic contour and its inversion. Significantly, it was discovered that the tone quality produced when a singer's head and neck postures followed the natural melodic contour of the melody was in no case considered to be the most pleasing of the conditions studied and that, in many cases, the tone quality produced when a singer's head and neck postures followed a map of the inversion of the melodic contour was judged to be much improved. The results of the study also indicate that the development of new technology for the general teaching studio, designed to address these effects, may be useful to these singers.     

Are Real-Time Displays of Benefit in the Singing Studio? An Exploratory Study

This article reports on an exploratory research project to evaluate the usefulness or otherwise of real-time visual feedback in the singing studio. The primary purpose of the work was not to optimize the technology for this application, but to work alongside teachers and students to study the impact of real-time visual feedback technology use on the students' learning experiences. An action research methodology was used to explore the benefit of real-time displays over an extended period. The experimental phase of the work was guided by a Liaison Panel of teachers and academics in the areas of singing, pedagogy, voice science, speech therapy, and linguistic science. Qualitative data were collected from eight students working with two professional singing teachers. The teachers and students acted as co-researchers under the action research paradigm. Teachers and students alike kept journals of their teaching and learning experiences. Singing lessons were observed regularly by the research team, coded for teacher and student behaviors, and all co-researchers were interviewed at the mid- and endpoint of the project. The use of technology had a positive impact on the learning process, and this is evidenced through case study data.     

Influence d'un ou de plusieurs groupements tertiobutyle sur le comportement magnétooptique du doublet libre d'un atome de phosphore tricoordonné

A magnetooptical study of some halogenotertiobutylphosphines is performed in order to improve the so-called regular relationship which seemed to exist between the magnetic rotation, ?dP, of the lone pair and the bond angles in PX₃ compounds. It is clearly shown that, in any case, ?dP is largely lower than the extreme value which was observed in PX₃ molecules for which XPX=100°. Thus, the existence of the previously invoked relationship vanishes and the question remains as to why there exists a maximum of ?dP for XPX of 100°.     

RF field dependence of memory echoes in LiNbO3 and GaAs powder

Measurements of the rf electric field dependence of the amplitude of the “memory” echo in LiNbO₃ and GaAs powders are reported. Consistent with the torque-rotation model, the dependence on each of the three applied rf pulses is linear in the low power regime. At high power, more complex behavior is found including an irreversible decrease in the echo amplitude when the third applied pulse is larger than the preceeding two pulses.     

Higher ?ech Theory

We introduce a notion of cover of level n for a topological space, or more generally any Grothendieck site, with the key property that simplicial homotopy classes computed along the filtered diagram of n-covers biject with global homotopy classes when the target is an n-type. When the target is an Eilenberg–MacLane sheaf, this specializes to computing derived functor cohomology, up to degree n, via simplicial homotopy classes taken along n-covers. Our approach is purely simplicial and combinatorial.     

Technology and equipment for hydrostatic treatment of materials

Abstract

The main requirements of the quality of products are the homogeneity of technological and service properties, the improved characteristics of strength and plasticity, endurance and brittle failure resistance. In recent years many investigations into developing the High Hydrostatic Pressure Technologies (HHPT) and equipment to meet these requirements have been carried out by scientific schools of Academicians, L. F. Vereshchagin, G. V. Kurdyumov, A. I. Tselikov and A. A. Galkin in the USSR. The physical basis of these technologies is represented by the plastic deformation effects under high pressure: material plasticization’, strain ageing², decrease of a carbide inhomogeneity³, use of a liquid as a machining tool⁴ etc. HHPT are widely spread and especially promising in metallurgy as the ferrous metals account for more than 96% of the total structural material consumption in machine building, while assortment of products is about 5000 profile sizes of bars, 30 000 profile sizes of tubes, 50 000 types of metalware.     

硅微结构惯性传感器的研制现状及应用前景

本文从介绍硅微结构惯性传感器的研制背景入手，分析了微米／纳米技术近年来的进展对发展硅微传感器的推动作用，重点介绍了美国主要公司有关硅微结构惯性仪表的研制现状，最后结合市场预测，提出笔者对我国发展硅微惯性传感器的几点浅见。