共查询到20条相似文献，搜索用时 24 毫秒
1.
2.
3.
《天津大学学报(英文版)》2003,(4)
JournalofNanotechnologyandPrecisionEngineering ,ratifiedbytheNewsandPubli cationAdministrationofP .R .C ,willbefirstissuedhomeandabroadinDec.2 0 0 3 ,quarter ly ,with 80 pagesperissue. JournalofNanotechnologyandPrecisionEngineeringprovidesaninternationalmediumforthepublicationsinscience,engineering ,technologyrelatedtothefollowingfourassociat edfields:Nanotechnology ,MicroElectro MechanicalSystem ,PrecisionMachiningandPre cisionMeasurement.JournalofNanotechnologyandPrecisionEngine… 相似文献
4.
5.
《天津大学学报(英文版)》2004,10(2):i001-i001
Journal of Nanotechnology and Precision Engineering was first issued home and abroad in Dec. 2003, quarterly, with 80 pages per issue. 相似文献
6.
INTRODUCTIONGastroesophagealrefluxdisease (GERD)isoneofthemostcommonchronicdisordersthatresultsfromabnormalrefluxofgastriccontentsintotheesophagus,affecting 10 %ofthepopu lationintheUnitedStates (Hawdenetal.,19 95 ) .Fortypercentofpatientswithsympo tomati… 相似文献
7.
STEWART Mark G 《天津大学学报(英文版)》2006,12(B09):8-15
A probabilistic risk assessment procedure is developed which can predict risks of explosive blast damage to built infrastructure, and when combined with life-cycle cost analysis, the procedure can be used to optimise blast mitigation strategies. The paper focuses on window glazing since this is a load-capacity system which, when subjected to blast loading, has caused significant damage and injury to building occupants. Structural reliability techniques are used to derive blast reliability curves for annealed and toughened glazing subjected to explosive blast for a variety of threat scenarios. The probabilistic analyses include the uncertainties associated with blast modelling, glazing response and glazing failure criteria. Damage risks are calculated for an individual window and for windows in the facade of a multi-storey commercial building. The paper shows an illustrative example of how this information, when combined with risk-based decision-making criteria, can be used to optimise blast mitigation strategies. 相似文献
8.
STEWART Mark G 《天津大学学报(英文版)》2006,12(Z1)
A probabilistic risk assessment procedure is developed which can predict risks of explosive blast damage to built infrastructure, and when combined with life-cycle cost analysis, the procedure can be used to optimise blast mitigation strategies. The paper focuses on window glazing since this is a load-capacity system which, when subjected to blast loading, has caused significant damage and injury to building occupants. Structural reliability techniques are used to derive blast reliability curves for annealed and toughened glazing subjected to explosive blast for a variety of threat scenarios. The probabilistic analyses include the uncertainties associated with blast modelling, glazing response and glazing failure criteria. Damage risks are calculated for an individual window and for windows in the facade of a multi-storey commercial building. The paper shows an illustrative example of how this information, when combined with risk-based decision-making criteria, can be used to optimise blast mitigation strategies. 相似文献
9.
Theoretical Calculation and Analysis of Slip and Deformation for Concrete Sandwich Panels 总被引：1，自引：0，他引：1
Slip and deformation of concrete sandwich panels under uniformly distributed loads is concerned. The effect of slip on the deformation of concrete sandwich panels are studied,and the analytical expressions of slip and deformation for concrete sandwich panels is obtained. These formulae can describe the slip distribution and account for its effect on deformation. In order to restrict the bound of formula, the formula of crack moment is obtained. The results of theoretical calculation are compared with those of tests and finite element methods. The comparison shows that the results of theoretical calculation are in accord with those of tests and finite element methods. So the theoretical calculation can be used to calculate slip and deformation of concrete sandwich panels in practical projects. 相似文献
10.
TANG Qian ZHU Cai-chao LIAO Xiao-yun LU Bo 《重庆大学学报(英文版)》2005,4(3):125-128
Traditional variation analysis methods are not applicable to non-rigid assemblies due to possible part deformation during the assembly process. This paper presents the use of finite element methods to simulate assembly deformation. The relationship between the parts＇ variation and the variation of the key points in final assembly for quality control is set up by calculating the spring back deformation after assembly. Moreover, the optimization method for non-rigid assembly variations based on finite element analysis is presented. The optimal objective is to reduce the manufacturing cost. The approach is implemented by using ANSYS and MATLAB. The test example shows that the proposed method is effective and applicable. 相似文献
11.
This study examined parents’ goals for reading ABC books with their children and their perceptions of page features. Factor analysis of a questionnaire answered by 225 parents of junior and senior kindergarten students revealed four goals for reading alphabet books. In order of importance as rated by parents the goals were: Learning to Read, Enjoyment and Bonding, Learning from Books, and Soothing the Child. Maternal education, number of ABC books owned, and ABC book reading frequency were related to parents’ goals. When viewing ABC pages, parents rated pages with little text, simple illustrations, and letter sound-word consistency as more appropriate for fulfilling purposes related to learning to decode than pages with a lot of text, complex illustrations, and letter sound-word violations. These perceptions are congruent with previous research and experts’ advice. However, parents rated pages with more complex illustrations as more appropriate for enjoyment, potentially putting books with complex illustrations at cross purposes with the previous goals. 相似文献
12.
13.
14.
There are increasing calls in the science education community for ‘science for citizenship’ as an important goal for the school science curriculum of the 21st century. The potential influence of portrayals of science and scientists in popular culture on the achievement of this goal is explored in this paper through a review of the literature. We develop a framework of important questions citizens ask in considering personal and social decision making in relation to science and technology issues, and how portrayals of science and scientists might contribute to this decision making process. 相似文献
15.
Leonie J. Rennie 《Research in Science & Technological Education》2013,31(2):121-133
The recent explicit inclusion of technology into the science component of the school curriculum in Western Australia necessitates changes in both curriculum materials and the nature of classroom teaching. This paper reports an investigation of the perceptions of technology of senior teachers who are heads of the science department in their schools, and relates these perceptions with those of a sample of 13‐year‐old pupils in this state. The investigation reveals that many teachers have a restricted view of technology which may be interpreted as a view that technology is dependent upon science. Such a view may neglect the historical aspects and societal influences on science and technology. Further, the available evidence indicates that local pupils have a low level of awareness of technology. The paper discusses the implications of these findings for curriculum change and suggests a starting point for achieving a successful balance in the teaching of technology, science and society issues in the classroom. 相似文献
16.
The main goal of the study reported in our paper is to characterize teachers’ choice of examples in and for the mathematics
classroom. Our data is based on 54 lesson observations of five different teachers. Altogether 15 groups of students were observed,
three seventh grade, six eighth grade, and six ninth grade classes. The classes varied according to their level—seven classes
of top level students and six classes of mixed—average and low level students. In addition, pre and post lesson interviews
with the teachers were conducted, and their lesson plans were examined. Data analysis was done in an iterative way, and the
categories we explored emerged accordingly. We distinguish between pre-planned and spontaneous examples, and examine their
manifestations, as well as the different kinds of underlying considerations teachers employ in making their choices, and the
kinds of knowledge they need to draw on. We conclude with a dynamic framework accounting for teachers’ choices and generation
of examples in the course of teaching mathematics.
相似文献
| Orit ZaslavskyEmail: |
17.
Construction and Analysis of Structured Preconditioners for Block Two-by-Two Matrices 总被引：3，自引：0，他引：3
白中治 《上海大学学报(英文版)》2004,8(4):397-405
For the large sparse block two-by-two real nonsingular matrices, we establish a general framework of structured precondi-tioners through matrix transformation and matrix approximations. For the specific versions such as modified block Jacobi-type, modi-fied block Gauss-Seidel-type, and modified block unsymmetric (symmetric) Gauss-Seidel-type preconditioners, we precisely describetheir concrete expressions and deliberately analyze eigenvalue distributions and positive definiteness of the preconditioned matrices.Also, we show that when these structured preconditioners are employed to precondition the Krylov subspace methods such as GMRESand restarted GMRES, fast and effective iteration solvers can be obtained for the large sparse systems of linear equations with blocktwo-by-two coefficient matrices. In particular, these structured preconditioners can lead to high-quality preconditioning matrices forsome typical matrices from the real-world applications. 相似文献
18.
LIU Xue-fei DU Xianglin FENG Tian-xiang 《重庆大学学报(英文版)》2006,5(1):53-56
On some necessary conditions for double pyramidal central configurations with concave heptagon for any given ratio of masses, the existence and uniqueness of a class of double pyramidal central configurations with concave heptagon base for nine-body problems is proved in this paper, and the range of the ratio cr of the circularity radius of the heptagon to the half-height of the double pyramidal central configuration involved in this class configurations is obtained, which is in the interval （√3/3,1.099 600 679）, and the configuration involved in the bodies with any σ∈ （√3/3, 1.099 600 679） can form a central configuration which is a uniquely central configuration is proved. 相似文献
19.
邱学绍 《重庆大学学报(英文版)》2003,2(1)
~~Super number roots and factorizations for a kind of polynomial@邱学绍$Information and Computation Department, Zhengzhou Institute of Light Industry, Zhengzhou450002, P.R. China~~ 相似文献
20.
This paper analyzes the outcomes of an innovative technology experience for students and teachers (ITEST) project, Mayor’s Youth Technology Corps (MYTCs) in Detroit, MI, which was funded by the NSF ITEST program. The MYTC project offered an integration of two technologies, geographic information system (GIS) and information assurance (IA), to stimulate students’ interests in science, technology, engineering, and mathematics (STEM) career pathways and learning opportunities among high schools in underserved communities of the City of Detroit. Pre- and post-surveys demonstrated that the MYTC students showed growth in nearly every area covered in the surveys, including dispositions about STEM career and learning. A STEM career goal measure showed that overall interest in having a career in STEM increased 9 % throughout the program, with an additional 10 % for those who participated in an internship experience, the capstone of the MYTC project. 相似文献