共查询到20条相似文献，搜索用时 31 毫秒
1.
Knut E. Aasmundtveit Bao Quoc Ta Quoc-Huy Nguyen Tormod B. Haugen Nils Hoivik Einar Halvorsen 《上海大学学报(英文版)》2013,(3):218-225
The integration of nanomaterials such as carbon nanotubes （CNTs） into microsystems is highly desirable, in order to make use of the unique nanomaterial properties in real devices. However, the CNTtomicrosystem integration is challenging to implement in a manufacturable, cost effective industrial process. This paper presents our work towards a process for making complete, integrated CMOS / MEMS systems with integrated CNT. We demonstrate the feasibility of the process, using roomtemperature process ing, lowcost equipment and consumables, and electrical control with automation possibilities. CNTs are directly integrated at the desired positions in the Si microsystem, forming closed Si / CNT / Si circuits. We explore different designs with the aim to obtain uniform and welldefined CNT synthesis conditions, and show that simplified designs can perform comparably to more complex ones. The Si / CNT / Si circuits obtained can show rectifying （Schottky like） or nearohmic behavior. Gas sensing possibilities are demonstrated, indicating the possibility of monitoring aging/ fermenting of food. Functionalization of CNTs is demon strated, using thermal evaporation of Sn and Pd, opening for selective and sensitive sensors for various gases and ana lytes. Detailed microscopic characterization of the obtained CNTs are presented. 相似文献
2.
The integration of water quality analysis simulation program （WASP） with a geographical information system （GIS） is presented.This integration was undertaken to enhance the data analysis and management ability of the widely used water quality model.Different types of data involved in WASP modeling were converted and integrated into GIS using a database method.The spatial data modeling and analysis capability of GIS were used in the operation of the model.The WASP water quality model was coupled with the environmental fluid dynamics code （EFDC） hydrodynamic model.A case study of the Lower Charles River Basin （Massachusetts,USA） water quality model system was conducted to demonstrate the integration process.The results showed that high efficiency of the data process and powerful function of data analysis could be achieved in the integrated model,which would significantly improve the application of WASP model in water quality management. 相似文献
3.
This paper focuses on document clustering by clustering algorithm based on a DEnsityTree （CABDET） to improve the accuracy of clustering. The CABDET method constructs a density-based treestructure for every potential cluster by dynamically adjusting the radius of neighborhood according to local density. It avoids density-based spatial clustering of applications with noise （DBSCAN） ＇s global density parameters and reduces input parameters to one. The results of experiment on real document show that CABDET achieves better accuracy of clustering than DBSCAN method. The CABDET algorithm obtains the max F-measure value 0.347 with the root node＇s radius of neighborhood 0.80, which is higher than 0.332 of DBSCAN with the radius of neighborhood 0.65 and the minimum number of objects 6. 相似文献
4.
An analytical sandwich beam model for piezoelectric bender elements is derived based on the first-order shear deformation theory （FSDT）, which assumes a single rotation angle for the whole cross-section and a quadratic distribution for coupled electric potential in piezoelectric layers. Shear coefficient is introduced to correct the effect of transverse shear strain on shear force and the electric displacement integration. Static and free vibration analyses of simply-supported bender elements are carried out for the sensor function. The results illustrate the high accuracy of the present model compared with the exact 2D solutions. 相似文献
5.
Fundamental principles from structural dynamics, random theory and perturbation methods are adopted to develop a new response spectrum combination rule for the seismic analysis of non-classically damped systems, such as structure-damper systems. The approach, which is named the perturbation spectrum method, can provide a more accurate evaluation of a non-classically damped system＇s mean peak response in terms of the ground response spectrum. To account for the effect of non-classical damping, all elements are included in the proposed method for seismic analysis of structure, which is usually approximated by ignoring the off-diagonal elements of the modal damping matrix. Moreover, as has been adopted in the traditional Complete Quadratic Combination （CQC） method, the white noise model is also used to simplify the expressions of perturbation correlation coefficients. Finally, numerical work is performed to examine the accuracy of the proposed method by comparing the approximate results with exact ones and to demonstrate the importance of the neglected off-diagonal elements of the modal damping matrix. In the examined cases, the proposed method shows good agreement with direct time-history integration. Also, the perturbation spectrum method leads to a more efficient and economical calculation by avoiding the integral and complex operation. 相似文献
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We present a high-resolution relaxation scheme for a multi-class Lighthill-Whitham-Richards （MCLWR） traffic flow model. This scheme is based on high-order reconstruction for spatial discretization and an implicit-explicit Runge-Kutta method for time integration. The resulting method retains the simplicity of the relaxation schemes. There is no need to involve Riemann solvers and characteristic decomposition. Even the computation of the eigenvalues is not required. This makes the scheme par- ticularly well suited for the MCLWR model in which the analytical expressions of the eigenvalues are difficult to obtain for more than four classes of road users. The numerical results illustrate the effectiveness of the presented method. 相似文献
8.
Movie title is the name of a movie which to some extent determines the audience’s choice to watch the movie or not.English movie title,as a special kind of English language,reflects language and culture of the specific English country.To better understand and appreciate the movie,it is essential to understand the cultural elements of the English movie title.The thesis with start with the introduction of movie title and its naming approaches,then analyze the three cultural elements that is historical,religious and linguistic cultural elements in English movie title in the hope of providing helpful background knowledge for Chinese audience to better appreciate the English culture. 相似文献
9.
Yael Fisher 《美中教育评论》2010,7(6):1-15
This paper reveals a new evaluation model, which enables educational program and project managers to evaluate their programs with a simple and easy to understand approach. The ＂index of success model＂ is comprised of five parameters that enable to focus on and evaluate both the implementation and results of an educational program. The integration of these parameters forms a complete and comprehensive picture, which in turn provides the most information on the success or failure of the program. The parameters are： （1） the relevance index, referring to an evaluation of predefined objectives; （2） the efficiency index, referring to the fiscal efficiency of the program; （3） the effectiveness index evaluating the attainment of the program＇s objectives; （4） the impact index gauging the effect on the consumers, for whom the program is undertaken; and （5） the final parameter is the program＇s sustainability index. Since Israel＇s education strategy currently leans towards site-based monitoring and evaluation, such a model can potentially be of great help to school management and staff. 相似文献
10.
Balakrishnan Mumandy Rossafri Mohammad Soon Fook Fong 《美中教育评论》2007,4(9):46-52,63
Instructional reform movements in the 1990s called for an effective and concurrent integration of various educational components. For effective classroom instructional reform, it was suggested that teaching method （pedagogy）, learning theory, and technology be promoted concurrently to form synergistic relationship. Thus, the primary purpose of this paper is to report a research that investigated the use of constructivism （learning theory） and technology in project-based learning （pedagogy） in elementary school classrooms. This paper consists of three main parts. The first part introduces the idea of integrating elements of pedagogy, learning theory and technology in a synergistic manner. The second part outlines the research findings of the extent of such integration in an elementary school. The final part of this paper provides suggestion on how these elements can be integrated in an effective and synergistic manner in order to bring about an instructional reform in education. 相似文献
11.
The purpose of this study is to promote more open-ended inquiry activities in junior high school science lessons in the current educational system with fixed textbooks. Researchers adapted existing curriculum-based experimental activities for more open-ended inquiry ones. In addition, the whole class was provided with more opportunities to explore complete activities in limited teaching time. This study used Hazel＇s proposals of levels of inquiry. The method was to carry out the current 8th grade experiments through the step-by-step teaching material modification （from levels of inquiry 0 to 2b） and to combine the experimental teaching method with the 5E （engage, explore, explain, elaborate, and evaluate） learning cycle. After a quasi-experimental study, we compared the traditional teaching method with the step-by-step open-ended inquiry teaching one on 8th graders＇ basic and integrated science process skills and academic achievements. The study result showed that the academic achievement in the experimental group, based on the same instructional time, was not worse than that in the control group. No significant difference was found on the total scores of the basic science process skills between the two groups, but a significant difference was found on the ＂predicting＂ dimension. There was a significant difference on the total scores of the integrated science process skills between the two groups. Significant differences were found on ＂interpreting data＂ as well as ＂experiment designing＂ dimensions. Hence, the study indicated that it could enhance students＇ inquiry ability through step-by-step openly inquiry levels to change the existing curricula, which served as a reference of educational reform. 相似文献
12.
Monolithic integration of resonant tunneling diodes (RTDs) and high electron mobility transistors (HEMTs) is an important development direction of ultra-high speed integrated circuit. A kind of top-RTD and bottom-HEMT material structure is epitaxied on InP substrate through molecular beam epitaxy. Based on wet chemical etching, metal lift-off and air bridge interconnection technology, RTD and HEMT are fabricated simultaneously. The peak-to-valley current ratio of RTD is 7.7 and the peak voltage is 0.33 V at room temperature. The pinch-off voltage is -0.5 V and the current gain cut-frequency is 30 GHz for a 1.0 μm gate length depletion mode HEMT. The two devices are conformable in current magnitude, which is suitable for the construction of various RTD/HEMT monolithic integration logic circuits. 相似文献
13.
Mark Twain, a mastermind of humor and realism, is seen as a giant in world literature. His humorous satire had great impact on the following men of letters; critics also attached significant importance to it and put forward various interpretations. Noticeably, his humor ous satire finds full expression in his famous short story, Running for Governor. In it, with humor and satire, he exposed the true features and hypocrisy of American democracy. The paper tries to analyze the basic elements which affected Mark Twain’s humorous satire, aiming at offering rational analysis of this humorous satire in Running for Governor as well as making Twain’s works readily understood. 相似文献
14.
The clock generator and OOK modulator for RFID (Radio Frequency Identification) presented in this paper consist of a current source and delay elements. The simple constant-gm structure is adopted in the current source design and the current consumption of the current source is only about 2 μA. The delay elements, the clock generator and OOK modulator are introduced in detail in the paper. The designed circuits are fabricated by 0.6 μm CMOS process. The area of the core circuit is only about 400 μmμ0 μm. The delay time of all three samples is in the range of 9 μs to 21 μs when the supply voltage varies from 2 V to 4 V. As the measured results satisfy the system requirements, these circuit structures are suitable for RFID application. 相似文献
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李文波 《希望月报(上半月)》2007,(12):150-151
Task-based language teaching(TBLT)is a new teaching method.?"Task"is a special term in language teaching and it's different from language exercise.It has its specific features,forms and teaching steps.There are varieties of tasks in English teaching,but the focus of every task is on solving a communicative problem,?which has some connections with a real world of learners'lives and learning experience,and which can arouse learners'interest,participation and sense of responsibility.The development of process of TBLT represents a change of focus a revolution in syllabus design.It starts from the learners'needs and emphasizes learning language by doing things.The basic principles for task-based syllabus design are authenticity,form-function integration and task dependency.The aim of this project is to introduce TBLT and it also seeks to carry out the method of TBLT in English classes. 相似文献
17.
Ling-Yu Liza Lee 《美中教育评论》2009,6(3):28-39
The purpose of the study is to teach urban young children music concepts and English by composing creative music and songs with contrast elements. The subjects were seven urban young children aged from three to four in a Taiwan kindergarten. The duration was twenty-four weeks, with two sessions per week. The teaching contents included Hello Song, Musical Movement, Music Appreciation and Goodbye Song. The study applied the thematic music elements to the teaching content. The main methodology was a qualitative study and quantitative data used to receive objective support. Assessment included a pre-test at the beginning, a post-test and participation observation at the end of the study. The head of the kindergarten, the classroom teacher and a parent completed activity feedback forms to obtain social validity. The results show that through the use of creative music pieces of contrast and song activities, urban young children＇s understanding of music concepts was progressive and English ability was improved. The study findings are： （1） Using contrastive music pieces is a good method for teaching very young urban children to understand music concepts; （2） Creating simple target objective songs with contrast elements is a good way for urban young children to learn simple English; （3） Music with contrastive elements could motivate urban young children to do movement spontaneously and learn the spoken language simultaneously; and （4） Contrastive music could be used for pre-classical music learning. 相似文献
18.
The technique of adaptive tree mesh is an effective way to reduce computational cost through automatic adjustment of cell size according to necessity. In the present study, the 2D numerical N-S solver based on the adaptive quadtree mesh system was extended to a 3D one, in which a spatially adaptive octree mesh system and multiple particle level set method were adopted for the convenience to deal with the air-water-structure multiple-medium coexisting domain. The stretching process of a dumbbell was simulated and the results indicate that the meshes are well adaptable to the free surface. The collapsing process of water column impinging a circle cylinder was simulated and from the results, it can be seen that the processes of fluid splitting and merging are properly simulated. The interaction of second-order Stokes waves with a square cylinder was simulated and the obtained drag force is consistent with the result by the Morison’s wave force formula with the coefficient values of the stable drag component and the inertial force component being set as 2.54. 相似文献
19.
<正>The space-charge layer(SCL)and surface depletion area(SDA)model for beveled p-n junction is presented.The surface space-charge density is calculated for depletion case of beveled p-n junction.Based on the finite difference method, the effect of the equivalent surface charge density on the surface depletion area for positively beveled p-n junction is also studied.Thyristors passivated with polyimide(PI)or polyester improved silicon paint(SP)are fabricated to verify the effect of equivalent surface charge on the peripheral surface of beveled p-n junction.The change of leakage current is sensitive to the surface charges.It indicates that the selection of passivation materials is a significant process to ensure the breakdown voltage capability of beveled devices. 相似文献
20.
This paper focuses on climate comfort degree evaluated from relationships between spatial characteristics and behaviors of a winter city.It is demonstrated that the influences of climatic factors on human comfort are remarkably different for different spatial characteristics and functions of the sites.An evaluation method of climatic comfort is propsed,in which attaining comfort is an adaptation process,and the dynamic changes in the process are according to the user’s subjective tendency to the variations of the spatial characteristics and functions of the space.The evaluation criteria are based on both physical and psychological hierarchy needs of a person,which include the spatial form for microclimatic conditions as well as the spatial social-economic characteristics of a site.To improve the local environment of a winter city by planning measurements,the Harbin Central Pedestrian Street is taken as an example in the application of the evaluation method,and different planning optimizing strategies are proposed accordingly.The results show that the pattern of climate comfort is characterized by reflecting the socialeconomic value and individual behavior characteristics. 相似文献