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Building Information Modeling for Environmental Impact Assessment in Early Design Phases: A Literature Review
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作者 Marie-France Stendahl Marie-Claude Dubois +1 位作者 Daniel Forgues Eilif Hjelseth 《Open Journal of Applied Sciences》 2022年第1期59-81,共23页
The building sector is the largest consumer of energy in industrial countries. Saving energy in new buildings or building renovations can thus lead to significant global environmental impacts. In this endeavor, buildi... The building sector is the largest consumer of energy in industrial countries. Saving energy in new buildings or building renovations can thus lead to significant global environmental impacts. In this endeavor, building information <span>modeling (BIM) and building energy modeling (BEM) are two important to</span>ols to make the transition to net-zero energy buildings (NZEB). So far, little attention has been devoted, in the literature, to discuss the connection between BIM, BEM, and Life-cycle assessment (LCA), which is the main topic of this article. A literature review of 157 journal articles and conference proceedings published between 1990 and 2020 is presented. This review outlines knowledge gaps concerning BIM, BEM, and environmental impact assessment. It suggests that defining the process with the right technology (at the right time) would result in a more integrated design process (IDP) and bridge current gaps. The most efficient way to improve process and technology is related to the competences of the architects, engineers and constructors (AEC). The review also indicates that the IDP in the early design phases (EDP) is in need of improvement for architects and engineers, where a better connection between design phases, specific levels of development (LOD) and BIM tools is needed. <span>Competences, process and technology are the three main themes addressed in the review. Their relation to design phases and LOD is discussed. The aim </span>is to propose possible solutions to the current hinders in BIM-to-BEM (BIM2BEM) and BIM-for-LCA (BIM4LCA) integration. 展开更多
关键词 Building Information Modeling (BIM) Building Energy Modeling (BEM) Life Cycle Assessment (LCA) Simulations Energy CARBON design Process design phases Level of Development
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Risk Assessment at the Design Phase of Construction Projects in Ghana
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作者 Maurice Azochiman Awuni 《Journal of Building Construction and Planning Research》 2019年第2期39-58,共20页
The study was carried out exclusively in Ghana to explore the approaches employed by consultants in risk assessment at the design phase of projects in Ghana. One hundred and fourteen (114) consultants were selected ou... The study was carried out exclusively in Ghana to explore the approaches employed by consultants in risk assessment at the design phase of projects in Ghana. One hundred and fourteen (114) consultants were selected out of a population of one hundred and eighty six (186) from three main professional associations in Ghana made up of the Ghana Institute of Architects, Ghana Institution of Engineers and the Ghana Institution of Surveyors (Quantity Surveying Division) practicing in Ghana for the study. Both primary and secondary data were collected. A descriptive survey was also used to observe and describe the presence, frequency or absence of characteristics of a phenomenon as it naturally occurred, in order to gain additional information. A questionnaire was also designed to collect data from the architects, engineers and quantity surveyors. The data was analyzed using Statistical Package for the Social Scientists (SPSS) 17.0. Descriptive and inferential statistics, such as frequency tables, percentages and cross tabulations were used in the data analysis and summaries. Simple tests of associations were undertaken by using Chi square and Cramer’s V statistics to compare relationships between variables. Again, relative importance index was also used to analyze some of the data by computing to deduce their rankings. The relative importance index was used to analyze some of the data by computing to deduce their rankings. The research revealed that majority of consultants had an average knowledge of risk management. Based on the findings it was recommended that consultants undergo advanced training in risk assessment. It was therefore suggested that consultancy firms should develop a set of laid down procedures for consultants to use in risk assessment in order that the use of intuition employed by majority is lessened. The challenges observed in risk assessment and the remedial steps suggested curtailing the detrimental effects of risks would be of wide importance to many developing economies. 展开更多
关键词 Construction INDUSTRY PROJECT RISK Management Assessment design phase
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Research on disruptive design pre-identification in the preliminary design phase of aero engine flow pass multidisciplinary optimization
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作者 Shaojing DONG Yufan FANG +2 位作者 Wentong HU Xiuli SHEN Gaoxiang CHEN 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2022年第11期264-276,共13页
In aero engine design, determining whether the preliminary design will have disruptive effects on the detailed design is the key to multidisciplinary design optimization in the preliminary design stage. In order to ad... In aero engine design, determining whether the preliminary design will have disruptive effects on the detailed design is the key to multidisciplinary design optimization in the preliminary design stage. In order to adapt to the non-orthogonal parameter value range caused by the selfconstrained parametric modeling method, a non-orthogonal space mapping method that maps the optimal Latin hypercube sampling points of the traditional orthogonal design space to the non-orthogonal design space is proposed. Based on the logical regression method in machine learning field, a kind of feasible domain boundary identification method is employed to identify whether the sample spatial response meets the relevant criteria. The method proposed in this paper is used to identify and analyze the key technologies of the high-pressure turbine mortise joint structure. It is found that the preliminary design of the aero engine may lead to the failure to obtain a mortise joint structure meeting the design requirements in the detailed design stage. The mortise joint structure needs to be pre-optimized in the preliminary design stage. 展开更多
关键词 Aero engine Disruptive design Flow pass multidisciplinary optimization Pre-identification Preliminary design phase
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SUSTAINABILITY CERTIFICATION SYSTEMS AS GUIDELINES FOR EARLY-PHASE URBAN DESIGN PROCESSES
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作者 Lotte B.Jensen Lærke Bjerre Lise Mansfeldt 《Journal of Green Building》 2016年第3期81-94,共14页
The German Sustainable Building Council(Deutsche Gesellschaft für Nachhaltiges Bauen or DGNB)has one of the most comprehensive sustainability certification systems for urban districts(UD).Their explicit aim is th... The German Sustainable Building Council(Deutsche Gesellschaft für Nachhaltiges Bauen or DGNB)has one of the most comprehensive sustainability certification systems for urban districts(UD).Their explicit aim is that the system should impact the very earliest design decisions.The Technical University of Denmark has tested the DGNB-UD system in two experimental design projects for similar locations to find out how it can be used in the early-phase design process.This paper describes these two independent design processes,compares them and discusses their general features.We found that DGNB-UD addresses a broad sustainable focus and can be used as a tool for setting sustainability goals from the very first design steps.The system tends to promote multifunctional compromise solutions that meet several criteria at the same time.Using the DGNB-UD certification system in the early design phases therefore does have some effect on the urban design in terms of a bias towards certain design traits. 展开更多
关键词 urban design urban design drivers ealiest design phases German Sustainable Building Council
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Optimal design of sintered Ce_9Nd_(21)Fe_(bal)B_1 magnets with a low-melting-point (Ce,Nd)-rich phase 被引量:10
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作者 Shu-lin Huang Hai-bo Feng +5 位作者 Ming-gang Zhu An-hua Li Yan-feng Li Ya-chao Sun Yue Zhang Wei Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2015年第4期417-422,共6页
A systemic investigation was done on the chemistry and crystal structure of boundary phases in sintered Ce9Nd21FebalB1 (wt%) magnets. Ce2Fe14B is believed to be more soluble in the rare-earth (RE)-rich liquid phas... A systemic investigation was done on the chemistry and crystal structure of boundary phases in sintered Ce9Nd21FebalB1 (wt%) magnets. Ce2Fe14B is believed to be more soluble in the rare-earth (RE)-rich liquid phase during the sintering process. Thus, the grain size and oxygen content were controlled via low-temperature sintering, resulting in high coercivity and maximum energy products. In addition, Ce formed massive agglomerations at the triple-point junctions, as confirmed by elemental mapping results. Transmission electron micros- copy (TEM) images indicated the presence of (Ce,Nd)Ox phases at grain boundaries. By controlling the composition and optimizing the preparation process, we successfully obtained Ce9Nd21FebalBx sintered magnets; the prepared magnets exhibited a residual induction, coerciv- ity, and energy product of 1.353 T, 759 kA/m, and 342 kJ/m3, respectively. 展开更多
关键词 MAGNETS liquid phases eutectic point ENRICHMENT optimal design
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A MICROMECHANICS ANALYSIS FOR THE MICROSTRUCTURE DESIGN OF A TWO-PHASE PSEUDOELASTIC COMPOSITE
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作者 孙庆平 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 1994年第2期162-168,共7页
A micromechanics analysis on the possibility of designing a two-phase pseudoelastic composite is made for the case where ductile transformable shape mem- ory alloy plastic particles are imbedded coherently in an elast... A micromechanics analysis on the possibility of designing a two-phase pseudoelastic composite is made for the case where ductile transformable shape mem- ory alloy plastic particles are imbedded coherently in an elastic matrix. It is demon- strated that a pseudoelastic stress-strain loop in a macroscopic loading-unloading cy- cle can be obtained by microscopically stress induced forward and reverse martensitic transformations in the SMA particles. The relation between the macroscopic stress- strain response and the material parameters of the constituents of this composite is quantified through the micromechanics calculations, which reveals that the best duc- tility and thus the greatest energy absorption capacity of this novel microstructure can be obtained by the optimum material design. 展开更多
关键词 COMPOSITE optimum material design two-phase pseudoelastic composite microstructure design
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Assessment of a Proposed Software Design for the Solution of Multi-Phase Mechanics Problems on Networked Laptops
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作者 Richard Harris Thomas Impelluso 《Intelligent Information Management》 2010年第7期391-397,共7页
This paper presents the design of a computational software system that enables solutions of multi-phase and multi-scale problems in mechanics. It demonstrated how mechanicians can design “process-driven” software sy... This paper presents the design of a computational software system that enables solutions of multi-phase and multi-scale problems in mechanics. It demonstrated how mechanicians can design “process-driven” software systems directly, and that such efforts are more suitable in solving multi-phase or multi-scale problems, rather than utilizing the “data-driven” approaches of legacy network systems. Specifically, this paper demonstrates how this approach can be used to solve problems in flexible dynamics. Then it suggests a view of mechanics algorithms as ‘state equilibrium’ enforcers residing as servers, rather than as computer programs that solve field equations. It puts forth the need for identical input/output files to ensure widespread deployment on laptops. Then it presents an assessment of the laptop platform. A software system such as the one presented here can also be used to supply virtual environments, animations and entertainment/education software with physics. 展开更多
关键词 SOFTWARE design MULTI-phase MECHANICS PROBLEMS NETWORKED LAPTOPS
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Design of a Hardware-Implemented Phase Calculating System for Feedback Control in the LHCD Experiments on EAST
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作者 刘强 梁吴 周永钊 《Plasma Science and Technology》 SCIE EI CAS CSCD 2009年第2期241-244,共4页
A fully hardware-implemented phase calculating system for the feedback control in the lower-hybrid current drive (LHCD) experiments is presented in this paper. By taking advantages of field programmable gate array ... A fully hardware-implemented phase calculating system for the feedback control in the lower-hybrid current drive (LHCD) experiments is presented in this paper. By taking advantages of field programmable gate array (FPGA) chips with embedded digital signal processing (DSP) cores and the Matlab-aided design method, the phase calculating algorithm with a square root operation and parallel process are efficiently implemented in a single FPGA chip to complete the calculation of phase differences fast and accurately in the lower-hybrid wave (LHW) system on EAST. 展开更多
关键词 lower-hybrid current drive (LHCD) hardware and parallel phase calculating FPGA Matlab-aided design
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基于Phase^2数值模拟的巷道支护参数优化研究 被引量:3
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作者 王富林 杨东辉 《煤炭技术》 CAS 北大核心 2017年第1期37-39,共3页
结合某矿回采巷道地质和技术条件,利用Phase^2数值模拟软件建立了不同锚杆支护参数的模型,通过分析巷道变形及应力分布特征,研究了不同锚杆间距和长度时巷道支护效果。结果表明:Phase^2数值模拟可以为巷道支护参数优化设计提供有效参考... 结合某矿回采巷道地质和技术条件,利用Phase^2数值模拟软件建立了不同锚杆支护参数的模型,通过分析巷道变形及应力分布特征,研究了不同锚杆间距和长度时巷道支护效果。结果表明:Phase^2数值模拟可以为巷道支护参数优化设计提供有效参考,优选支护方案效果良好,有效维护了巷道的稳定性。 展开更多
关键词 巷道支护 优化设计 数值分析 phase^2
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Implications of Design, Management and Recession Phase in Drip Irrigation on the Total Distribution Efficiency in Blueberry (Vaccinium corymbosum L.) Crops in Areas with High Slopes in Concordia, Argentina 被引量:1
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作者 A. Pannunzio E. A. Holzapfel +1 位作者 P. Texeira Soria F. Bologna 《Agricultural Sciences》 2016年第7期469-478,共11页
The increase of human population generates the need to improve the efficiency of food production. A thorough planning is required following the scope of economic and sustainable development, being irrigation a basic t... The increase of human population generates the need to improve the efficiency of food production. A thorough planning is required following the scope of economic and sustainable development, being irrigation a basic tool, however water availability is restricted and it obliges farmers to progress increasing water productivity. Irrigation uses around 70% of total available fresh water, while irrigation water application efficiency is around 40%. Irrigation systems must follow strong criteria at the design stage to achieve high values of water productivity. Maintenance is indispensable to follow the original functioning level of those systems. At last the daily precise management of systems, following soil water potential, considering the effective rain storage at root depth of the crop and the evolution of daily evapotranspiration, preserving natural resources, are relevant to achieve low values of water footprint of this crop. In an 8 year drip irrigation system, the Uniformity Coefficient of Christiansen (UCC) measured was 95.14%;the Uniform Coefficient of the Minor Quart (UCMQ) was 93.16%. The Total Distribution Efficiency (EDT) was 95.13% when measurements finished while the irrigation systems is of. When measurements also considered the volume collected during the “recession phase in drip irrigation” and the “volume of water collected during recession phase in drip irrigation” collected at different points, EDT was 95.13%. Moreover it can be seen that when three different typical soil of the area were considered, the EDT was, 91.85%, 91.47% and 90.30% respectively, according with different water storage capacity of each soil. The Total Distribution Efficient is a strong method, to evaluate the design and management of drip irrigation systems, under different design criteria, management practices and maintenance of the systems. Water footprint in a blueberry (Vaccinium corymbosum L.) crop with drip and sprinkler anti-frost system, were measure and values obtained were 846, 310, 223, 212, 172 and 218 liters per kg of fresh fruit in the period 2010-2015. The UCC and the UCMQ reflects properly the irrigation design, while the EDT reflects irrigation design, management and maintenance. Water footprint is at last the strong tool to evaluate design and operation of the irrigation system and crop management. 展开更多
关键词 Recession phase in Irrigation Water Management Drip Irrigation Irrigation design Criteria Drip Irrigation Management Blueberry Crop Snow Chaser Variety Irrigation Uniformity Water Footprint
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Phased-MIMO雷达恒模正交波形优化设计 被引量:2
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作者 陈志坤 冯翔 +2 位作者 李风从 乔晓林 赵宜楠 《系统工程与电子技术》 EI CSCD 北大核心 2016年第6期1288-1294,共7页
由于受到发射机功率和波形能量的限制,现代雷达系统一般选择恒模波形来实现发射功率的最大化利用。针对Phased-MIMO雷达子阵单元之间的恒模正交波形优化设计问题,基于矩阵谱逼近的思想,本文提出了一种新的波形设计框架。首先假设输出信... 由于受到发射机功率和波形能量的限制,现代雷达系统一般选择恒模波形来实现发射功率的最大化利用。针对Phased-MIMO雷达子阵单元之间的恒模正交波形优化设计问题,基于矩阵谱逼近的思想,本文提出了一种新的波形设计框架。首先假设输出信干比的需求得到划分的子阵数目,根据最大信噪比准则对子阵单元进行波束形成,提高了雷达系统的抗干扰性能,其次采用迭代矩阵谱逼近算法(iterative matrix spectral approximation algorithm,IMSAA)对子阵单元之间的正交波形进行优化设计,相对于multi-CAN算法,该算法能够获得更好的相关性能,而且运算效率较高,最终实现了恒模波形的优化设计。仿真结果证明了算法的有效性。 展开更多
关键词 phased-MIMO雷达 波形设计 正交波形 恒模波形
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The “Static” and “Dynamic” Design Verification Stages of the Lean Development Process: Automotive Industry 被引量:3
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作者 F. Ali Paker 《World Journal of Engineering and Technology》 2020年第1期74-91,共18页
he design verification steps that take place in today’s automotive industry, which constitute the values of each successive or simultaneous phase in the new product development process, create a complex structure wit... he design verification steps that take place in today’s automotive industry, which constitute the values of each successive or simultaneous phase in the new product development process, create a complex structure with the inclusion of each new technology and discipline. Therefore, step by step, each design verification phase definition in the flow contains important phase transition measurements or approval tolerances that ensure the simplicity and continuity of vehicle development processes. In addition, classification of design verification stages within the framework of this study or evaluation in two classes (static and dynamic) is a new approach, but it is a synthesis with the analysis of the new product development process. The vehicle’s basic structure, which constitutes the ergonomic and functional requirements of the vehicle in a static environment, takes into account the dynamic environment variables with crash or accident tests. Increasing new technology adaptations in the automotive industry have changed the new product development process that performs this function structurally and created the concept of design verification under consecutive or simultaneous process simplicity. From the autonomous driving to the use of alternative energy, possible accident scenarios and design verification phase transitions in the integration of parts and systems of the newly developed vehicle create a new structure that models and directs the lean product development process especially in the automotive industry in the coming days. In the lean product development process that takes place in the automotive industry, the design verification transition steps or the approval-control analysis of the development stages, which form a new and effective approach, are re-modeling the entire flow. Therefore, successful execution of design verification steps used in the control of new interdisciplinary product development phase transitions provides value creation.?Within the scope of this study, the effectiveness of the static and dynamic design verification steps, which are carried out in 5 global automotive companies included in the research, which constitute the stage transitions of the new product development process, has been measured. Apart from the design verification transition stages, the process variables that differ among the automotive companies involved in the research are excluded from the scope of this study. In other words, in field researches in the automotive industry, new vehicle design steps or basic engineering steps in the new product development process steps, while creating independent fixed variables, interdisciplinary collaborations, static and dynamic design verification transition stages they perform, or their sequence in the basic flow, is accepted as a dependent variable. Therefore, in the study, the positive effect of the automotive companies that included the static and dynamic design verification phase transition approvals in the lean product development process was investigated. Under the comparative analysis structure of the research, the effect of automotive companies, which accept international vehicle specifications as static design verification input, on market performance has been examined in depth. The detailed depth in the comparison analysis conducted under the second field studies of the study is due to the prediction of dynamic design verification stages to provide a high impact on the market performance, according to the static verification analysis. The new product development stages of the dependent variables were fixed and the flow-oriented?“effect”?of the independent variables in the basic process influenced by the design verification activities was analyzed under the new automotive industry company comparisons. In addition, the impact of the automotive design activities that make up the comparison analysis of the research on the scope of the lean product development stage and its effect on the basic process flow has been demonstrated competition-oriented. Therefore, sub-variables, options, criteria, results, which form a defined comparison problem, create basic test values that affect the problem. 展开更多
关键词 design Verification phaseS LEAN Development PROCESS AUTOMOTIVE Industry design PROCESS
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Metric Based Testability Estimation Model for Object Oriented Design: Quality Perspective
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作者 Mahfuzul Huda Yagya Dutt Sharma Arya Mahmoodul Hasan Khan 《Journal of Software Engineering and Applications》 2015年第4期234-243,共10页
The quality factor of class diagram is critical because it has significant influence on overall quality of the product, delivered finally. Testability has been recognized as a key factor to software quality. Estimatin... The quality factor of class diagram is critical because it has significant influence on overall quality of the product, delivered finally. Testability has been recognized as a key factor to software quality. Estimating testability at design stage is a criterion of crucial significance for software designers to make the design more testable. Taking view of this fact, this paper identifies testability factors namely effectiveness and reusability and establishes the correlation among testability, effectiveness and reusability and justifies the correlation with the help of statistical measures. Moreover study developed metric based testability estimation model and developed model has been validated using experimental test. Subsequently, research integrates the empirical validation of the developed model for high level acceptance. Finally a hypothesis test performs by the two standards to test the significance of correlation. 展开更多
关键词 TESTABILITY TESTABILITY Model EFFECTIVENESS REUSABILITY TESTABILITY FACTORS design phase
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Calculation and Inspection of Alloy Design of Cr-W- Mo-V High Alloy Steel Addition Niobium for Machinery Knives 被引量:1
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作者 Yongqing Ma Ming Hu 《材料科学研究(中英文版)》 2015年第1期8-14,共7页
关键词 设计计算 高合金钢 合金设计 机械刀具 钒合金 微量铌 钨钼 MC碳化物
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WC-Ni基硬质合金的基础研究进展
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作者 张立 崔焱茗 +4 位作者 聂仁鑫 徐涛 张维 龙坚战 刘向中 《硬质合金》 CAS 2024年第3期237-251,共15页
WC-Ni基硬质合金可应用在磁性材料成形模具和核主泵机械密封关键部件等极端工况领域。由于材料体系的本征特性,WC-Ni基硬质合金的高性能化和质量稳定性控制一直面临挑战。两相区碳窗口、固液转变温度、液相烧结过程中的润湿行为,以及合... WC-Ni基硬质合金可应用在磁性材料成形模具和核主泵机械密封关键部件等极端工况领域。由于材料体系的本征特性,WC-Ni基硬质合金的高性能化和质量稳定性控制一直面临挑战。两相区碳窗口、固液转变温度、液相烧结过程中的润湿行为,以及合金组元在黏结相中的固溶特性,是硬质复合材料成分及其制备工艺设计的关键参数。本文以制备工艺体系最完善的WC-Co基硬质合金为参比对象,从上述4个方面对WC-Ni基硬质合金的本征特性及其研究进展进行综述,旨在强化对WC-Ni基硬质合金本征特性的理解,为高性能WC-Ni基硬质合金新材料高效开发提供参考。 展开更多
关键词 WC-Ni基硬质合金 材料设计 工艺设计 相图 润湿行为 黏结相固溶特性
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Decoding the Moon Phase Display Device over the Front Dial of the Antikythera Mechanism
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作者 LIN Jian Liang YAN Hong Sen 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第4期676-683,共8页
The Antikythera mechanism is the most famous ancient astronomical calculator. The damaged excavation is a critical constraint for decoding the mechanism completely. By the systematic reconstruction design methodology,... The Antikythera mechanism is the most famous ancient astronomical calculator. The damaged excavation is a critical constraint for decoding the mechanism completely. By the systematic reconstruction design methodology, all feasible designs of the moon phase display device, which is one of the unclear mechanisms of the Antikythera mechanism, are reconstructed. These designs, including ordinary gear trains and epicyclic gear trains, are the simplest designs and satisfy the surviving evidence. The Antikythera mechanism and its reconstruction designs presented by LIN and YAN are introduced first. Three pointer types of the Antikythera mechanism are concluded based on their display motions and the orientation of the mechanism. In accordance with the analysis of the available interior reconstruction designs and the surviving evidence, four feasible designs of the moon phase display device are generated. All of them utilize the ball pointer with black and white that rotates around the radial axis to show cyclic moon phase. Two of these four feasible reconstruction designs are driven by one input source, and their bronze disks are fixed and rotatable respectively. Both of the remaining reconstruction designs are driven by two input sources, and their bronze disks are rotatable. Therefore, the four reconstruction designs of the moon phase display device reveal all possible display conditions of the moon phase pointers and the possible purposes of the bronze disk. 展开更多
关键词 Antikythera mechanism moon phase display device reconstruction design gear train
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The Definition of Task in Task-Based Language Teaching and The Factors Considered in Task Design
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作者 朱雅莉 《海外英语》 2018年第14期263-264,共2页
Task-based language teaching(TBLT)has caused considerable interests among curriculum developers,language testers and language teachers during the past several decades.In order to use the approach rightly,throughout li... Task-based language teaching(TBLT)has caused considerable interests among curriculum developers,language testers and language teachers during the past several decades.In order to use the approach rightly,throughout literature review,the essay is going to analyze what the task is critically and the factors teachers should consider when they design tasks.At the end of the study,it is concluded that even though the definition of task is various,the main criteria are that a task is mainly focusing on meaning;has a clear goal;involves the outcome;and is related to the real world.When design tasks,teachers need to balance the fluency,accuracy and complexity,making task difficulties be appropriate to students’levels,considering thematic content and the range of task types and the phases of tasks. 展开更多
关键词 英语 学习方法 阅读
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A 4-channel 3 Tesla phased array receive coil for awake rhesus monkey fMRI and diffusion MRI experiments 被引量:2
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作者 Mark Haig Khachaturian 《Journal of Biomedical Science and Engineering》 2010年第11期1085-1092,共8页
Awake monkey fMRI and diffusion MRI combined with conventional neuroscience techniques has the potential to study the structural and functional neural network. The majority of monkey fMRI and diffusion MRI experiments... Awake monkey fMRI and diffusion MRI combined with conventional neuroscience techniques has the potential to study the structural and functional neural network. The majority of monkey fMRI and diffusion MRI experiments are performed with single coils which suffer from severe EPI distortions which limit resolution. By constructing phased array coils for monkey MRI studies, gains in SNR and anatomical accuracy (i.e., reduction of EPI distortions) can be achieved using parallel imaging. The major challenges associated with constructing phased array coils for monkeys are the variation in head size and space constraints. Here, we apply phased array technology to a 4-channel phased array coil capable of improving the resolution and image quality of full brain awake monkey fMRI and diffusion MRI experiments. The phased array coil is that can adapt to different rhesus monkey head sizes (ages 4-8) and fits in the limited space provided by monkey stereotactic equipment and provides SNR gains in primary visual cortex and anatomical accuracy in conjunction with parallel imaging and improves resolution in fMRI experiments by a factor of 2 (1.25 mm to 1.0 mm isotropic) and diffusion MRI experiments by a factor of 4 (1.5 mm to 0.9 mm isotropic). 展开更多
关键词 4-Channel FMRI RF COIL design MONKEY SNR G-FACTOR Diffusion MRI phased Array
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IRS辅助的车联网相移设计和信道对齐策略
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作者 王汝言 王康 +2 位作者 崔亚平 何鹏 吴大鹏 《系统工程与电子技术》 EI CSCD 北大核心 2024年第2期761-769,共9页
针对车联网中车辆的动态移动以及信号的随机散射所导致的信道快速变化问题,研究了智能反射面(intelligent reflecting surface,IRS)辅助的车联网通信并提出了联合相移设计和信道对齐策略,以削减车联网中多普勒频移的影响并提升通信性能... 针对车联网中车辆的动态移动以及信号的随机散射所导致的信道快速变化问题,研究了智能反射面(intelligent reflecting surface,IRS)辅助的车联网通信并提出了联合相移设计和信道对齐策略,以削减车联网中多普勒频移的影响并提升通信性能。提出的策略由两个阶段构成。在第一阶段设计IRS的相移以改善级联信道的衰落状态,在策略的第二阶段进行修正函数的设计,实现了直接信道和级联信道的信道对齐,从而减少直接信道快衰落状态对通信性能的影响。通过联合相移设计和信道对齐策略中设计的反射相移以及修正函数,实现了通信性能的提升。仿真结果表明,所提策略相比于相移优化策略可以提升8.8%的频谱效率。 展开更多
关键词 车联网 智能反射面 衰落信道 相移设计
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Study On Anti-Blocking Agent of Calcium Chloride Hexahydrate Phase Change Materials
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作者 Peng Wang Yadong Yuan +2 位作者 Fengyan Li Yajun Yang Liuying Qian 《化学发展前沿(中英文版)》 2014年第3期29-34,共6页
关键词 相变材料 防粘连剂 氯化钙 水合物 十六烷基三甲基溴化铵 十二烷基苯磺酸钠 代理 EDTA二钠
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