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设数法解题举隅
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作者 李长松 《教育科学论坛》 1995年第4期26-26,共1页
小学毕业总复习时,我们经常碰到一些条件很抽象的数学题(亦称无数字题目),指导学生解答这一类型的题目,采用设数法来解比较简便有效。如:(1)一个圆柱和一个圆锥的高相等,圆锥的底面直径等于圆柱的底面半径,圆锥的体积是圆柱体积的几分之... 小学毕业总复习时,我们经常碰到一些条件很抽象的数学题(亦称无数字题目),指导学生解答这一类型的题目,采用设数法来解比较简便有效。如:(1)一个圆柱和一个圆锥的高相等,圆锥的底面直径等于圆柱的底面半径,圆锥的体积是圆柱体积的几分之内? 解:设圆柱的高为3,则圆锥的高也为3;圆柱底面半径为4,则圆锥底面半径为2, 展开更多
关键词 设数法 圆锥 圆柱体 总复习 学题 底面 半径 题目 小学 体积
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巧用设数法
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作者 凌小敏 段小军 《湖南教育(上旬)(A)》 1997年第7期43-43,共1页
小学数学中经常出现一些条件十分抽象的题目。对这些题目,学生理解起来比较困难。教学时,教师可用设数的方法,把抽象的条件具体化,使题目由难变易。 例1 一个长方形的面积是48平方厘米,当它的长扩大4倍,宽缩小3倍时,它的面积是( )平方... 小学数学中经常出现一些条件十分抽象的题目。对这些题目,学生理解起来比较困难。教学时,教师可用设数的方法,把抽象的条件具体化,使题目由难变易。 例1 一个长方形的面积是48平方厘米,当它的长扩大4倍,宽缩小3倍时,它的面积是( )平方厘米。 这类题目,不出现分量。 展开更多
关键词 设数法 东方红小学 巧用 衡阳市 小学 长方形 教师 变化情况 分量 教学
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用设数法解应用题
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作者 李彬宇 《教育实践与研究》 2002年第1期65-65,共1页
设数,任何数都可以,设'1'为特例.设已知两个量的最小公倍数最简便.
关键词 小学 应用题 设数法 最小公倍 学教学
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“设数法”解题例谈
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作者 于园忠 谢水林 《小学教学研究》 2002年第4期26-26,共1页
在小学数学竞赛中,常常会遇到一些看起来缺少条件,似乎很难解答的题目,但仔细分析就可以发现,题目中缺少的条件,对于答案并无影响,这时我们可用“设数法”来求解。举例说明如下:
关键词 小学 学竞赛题 解题方 设数法
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用设数法巧解几何竞赛题
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作者 沈盛 《陕西教育(教学)》 1997年第10期39-39,共1页
《陕西教育》1997年第4期刊登了“独辟蹊径,化难为易”一文,读后深受启发。的确在小学数学奥林匹克竞赛试题中,有些几何题难度较大,思考性强,但并非高不可攀,只要能把握适当的解题方法就会化难为易、化繁为简.设数法就是一类几何竞赛题... 《陕西教育》1997年第4期刊登了“独辟蹊径,化难为易”一文,读后深受启发。的确在小学数学奥林匹克竞赛试题中,有些几何题难度较大,思考性强,但并非高不可攀,只要能把握适当的解题方法就会化难为易、化繁为简.设数法就是一类几何竞赛题的一种巧妙的解题方法。现举几例说明如下: 例1.如图1,长方形面积为35平方厘米,左边直角三角形的面积为5平方厘米。 展开更多
关键词 设数法 竞赛题 解题方 奥林匹克竞赛试题 化难为易 小学 巧解 一般解 阴影部分 直角三角形
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“设数法”巧解题
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作者 孙立波 《小学生必读(中年级版)》 2008年第3期46-46,共1页
一个数乘以4,它们的积等于60,这个数是多少? 60÷4=15。换一种方法:假如这个数是5,5×4=20。因为60是20的3倍,所以原数就是5的3倍,也就是15。
关键词 设数法 自然 巧解 解答 相加 已知 未知 结果
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设数法
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作者 曹茜 《小学生学习指导(高年级)》 2016年第11期36-37,共2页
有些较复杂的数学问题,初看似乎缺少某些条件或数字,造成理解的困难,为此我们可以巧妙应用“设数法”,也就是先设这个条件对应的数为某一个确定值或用字母来表示,从而使问题变得简单。
关键词 中学教育 设数法 确定值
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Design Method for Optimizing the Interactive Interface of Live Broadcasting Platform for the Elderly Users
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作者 WEI Bi-ze FAN Wei DUAN Ying-ke 《印刷与数字媒体技术研究》 CAS 北大核心 2024年第4期167-178,共12页
In the era of network live broadcasting for everyone,the development of live broadcasting platforms is also more intelligent and diversified.However,in the face of a large group of elderly users,the interface interact... In the era of network live broadcasting for everyone,the development of live broadcasting platforms is also more intelligent and diversified.However,in the face of a large group of elderly users,the interface interaction design mode used is still mainly based on the interaction mode for young groups,and is not designed for elderly users.Therefore,a design method for optimizing the interaction interface of live broadcasting platform for elderly users was proposed in this study.Firstly,the case study method and Delphi expert survey method were used to determine the design needs of elderly users and the design mode was analysed.Secondly,the orthogonal design principle was used to design a test sample of the interactive interface of live broadcasting platform applicable for the elderly users,and then a user evaluation system was established to calculate the weights of the design elements using hierarchical analysis,and then the predictive relationship between the design mode of the interactive interface of live broadcasting platform and the elderly users was established by Quantitative Theory I.Finally,Genetic Algorithm was applied to generate the optimized design scheme.The results showed that the design method based on the Genetic Algorithm and the combination of Quantitative Theory can scientifically and effectively optimize the design of the interactive interface of the live broadcasting platform for the elderly users,and improve the experience of the elderly users. 展开更多
关键词 Live broadcasting platform Interaction design Elderly users Genetic Algorithm Quantitative Theory I
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RESEARCH OF THE PARAMETRIC ASSEMBLY METHOD
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作者 孙知信 陈文亮 +1 位作者 丁秋林 张娟 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1997年第2期165-169,共5页
The parametric part assembly generation method is presented. Based on the parametric part generated by means of constructive-element, through interactively inputting the relationships of the location and the assembly,... The parametric part assembly generation method is presented. Based on the parametric part generated by means of constructive-element, through interactively inputting the relationships of the location and the assembly, and by compiling operations like movement and rotation, the assembly drawing is created so as to implement the occurrence of the parameterizations of the assembly and the part drawing. The data structure of the assembly part and the key technologies of hidden line removal in the implementation of assembly process, etc. , are described in detail. 展开更多
关键词 ASSEMBLING PARAMETERS product modelling design methodology parametric drawing hidden line removal
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Methods of Random Fatigue Design for Vehicle Transmission System Components
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作者 项昌乐 陈欣 钟其水 《Journal of Beijing Institute of Technology》 EI CAS 2000年第4期353-357,共5页
Some representative working conditions were measured, and the amplitude distribution rule of each representative working condition after analysis of measured data was got. The building of 2 D distributing function be... Some representative working conditions were measured, and the amplitude distribution rule of each representative working condition after analysis of measured data was got. The building of 2 D distributing function between the range and the mean of random load was discussed. Experiment was carried out to get the fatigue strength data of the material of transmission component. Accessing the P S a S m N camber of combined load of bending and torsion on this material after analysis. And the process of calculating the 2 D fatigue life in multi working condition was discussed. 展开更多
关键词 random fatigue design rainflow counting working condition distributing function PSa SmNcambP
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ROBUST CONTROL OF A CLASS OF NONLINEAR SYSTEM WITH TIME-VARYING PAR AMETRIC UNCERTAINTIES
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作者 朱永红 姜长生 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2003年第1期97-102,共6页
A class of triangular non li near system with disturbances which has unknown multiplicative time varying par ametric uncertainties in each virtual control is treated by a backstepping techn ique. The controller desig... A class of triangular non li near system with disturbances which has unknown multiplicative time varying par ametric uncertainties in each virtual control is treated by a backstepping techn ique. The controller designed for all admissible uncertainties can guarantee tha t all states of its closed loop system are uniformly bounded. The robust contro ller design algorithm and a sufficient condition of the system stability are giv en. In addition, the closed loop system has an ISS property when the multiplica tive time varying parametric uncertainties are viewed as inputs to the system. Thus, this design provides a way to prevent a destabilizing effect of the multip licative time varying parametric uncertainties. Finally, simulational example i s given and simulational result shows that the controller exhibits effectiveness and excellent robustness. 展开更多
关键词 nonlinear system robus t control backstepping design
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Optimization of process parameters for producing AA6061/SiC nanocomposites by friction stir processing 被引量:3
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作者 M. SALEHI M. SAADATMAND J. AGHAZADEH MOHANDESI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第5期1055-1063,共9页
Design of experiment (DOE) was applied to determining the most important factors which influence ultimate tensile strength (UTS) of AA6061/SiC nanocomposites produced by friction stir processing (FSP). Effect of... Design of experiment (DOE) was applied to determining the most important factors which influence ultimate tensile strength (UTS) of AA6061/SiC nanocomposites produced by friction stir processing (FSP). Effect of four factors, including rotational speed, transverse speed, tool penetration depth and pin profile, on UTS, was investigated. By Taguchi method, the optimum of process parameters were determined. Analysis of variance shows that the rotational speed is the most influential parameter. The statistical results depict that UTS for threaded pin is larger than that for square pin. Also, the higher the rotational speed and the lower the transverse speed, the higher the UTS. 展开更多
关键词 AA6061/SiC nanocomposites Taguchi parametric design approach friction stir processing analysis of variance
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3D structure parameterization design and modeling for irregular structure of stope bottom 被引量:3
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作者 曾庆田 Wang Liguan 《High Technology Letters》 EI CAS 2016年第1期55-62,共8页
Stope mining design is a very important and complicated task in daily production design and technical management of an underground mine.Based on workface technology and human-computer interaction technology,this study... Stope mining design is a very important and complicated task in daily production design and technical management of an underground mine.Based on workface technology and human-computer interaction technology,this study introduces a method of 3D parametric design for the irregular structure of stope bottoms,and focuses on solving technical problems in surface modeling of stope bottom structure.Optimization of the minimum span length algorithm(MSLA) and the shortest path search algorithm(SPSA) is conducted to solve the problem of contour-line based instant modeling of stope bottom structures,which makes possible the 3D parametric design for irregular structure of stope bottom.Implementation process and relevant methods of the proposed algorithms are also presented.Feasibility and reliability of the proposed modeling method are testified in a case study.In practice,the proposed 3 D parameterization design method for irregular structure stope bottom proves to be very helpful to precise 3D parametric design.This method is capable of contributing to improved efficiency and precision of stope design,and is worthy of promotion. 展开更多
关键词 irregular stope bottom structure STOPE structure parameterization design surface reconstruction modeling
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Adaptive polarization i mage fusion based on regional energy dynamic weighted average 被引量:2
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作者 ZHAO Yong-qiang PAN Quan ZHANG Hong-cai 《Optoelectronics Letters》 EI 2005年第3期224-227,共4页
According to the principle of polarization imaging and the relation between Stokes parameters and the degree of linear polarization, there are much redundant and complementary information in polarized images. Since ma... According to the principle of polarization imaging and the relation between Stokes parameters and the degree of linear polarization, there are much redundant and complementary information in polarized images. Since man-made objects and natural objects can be easily distinguished in images of degree of linear polarization and images of Stokes parameters contain rich detailed information of the scene, the clutters in the images can be removed efficiently while the detailed information can be maintained by combining these images. An algorithm of adaptive polarization image fusion based on regional energy dynamic weighted average is proposed in this paper to combine these images. Through an experiment and simulations,most clutters are removed by this algorithm. The fusion method is used for different light conditions in simulation, and the influence of lighting conditions on the fusion results is analyzed. 展开更多
关键词 偏振现象 图象处理 模拟算
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Oil–water pre-separation with a novel axial hydrocyclone 被引量:13
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作者 Meili Liu Jiaqing Chen +2 位作者 Xiaolei Cai Yanhe Han Si Xiong 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第1期60-66,共7页
A novel hydrocyclone with guide vanes, named as axial hydrocyclone(AHC), is designed to tackle the problem of oil–water separation faced by most mature oilfields. Optimal design of the AHC is carried out by using num... A novel hydrocyclone with guide vanes, named as axial hydrocyclone(AHC), is designed to tackle the problem of oil–water separation faced by most mature oilfields. Optimal design of the AHC is carried out by using numerical methods. The effects of guide vanes, cone angle, tapered angle and overflow pipe on the oil–water separation are discussed in this paper. The results show that a double swirling flow is generated in the tapered section where oil–water separation occurs. Both the cylindrical and the tapered section have important influences on AHC performance. On the basis of single factor results, response surface methodology is employed to optimize the AHC design. The experimental results indicate that the novel AHC has an excellent performance for the oil–water separation. 展开更多
关键词 Axial hydrocyclone Oil-water pre-separation Computational fluid dynamicsLow resistance Structure design
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DESIGN OF TERNARY COUNTER BASED ON ADIABATIC DOMINO CIRCUIT 被引量:1
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作者 Yang Qiankun Wang Pengjun Zheng Xuesong 《Journal of Electronics(China)》 2013年第1期104-110,共7页
By researching the ternary counter and low power circuit design method, a novel design of low power ternary Domino counter on switch-level is proposed. Firstly, the switch-level structure expression of ternary loop op... By researching the ternary counter and low power circuit design method, a novel design of low power ternary Domino counter on switch-level is proposed. Firstly, the switch-level structure expression of ternary loop operation circuit with enable pin is derived according to the switch-signal theory, and the one bit ternary counter is obtained combining the ternary adiabatic Domino literal operation circuit and buffer. Then the switch-level structure expression of enable signal circuit is derived, and the four bits ternary counter is obtained by cascade connection. Finally, the circuit is simulated by Spice tool and the output waveforms transform in proper order indicating that the logic function is correct. The energy consumption of the four bits ternary adiabatic Domino counter is 63% less than the conventional Domino counterpart. 展开更多
关键词 Ternary counter Adiabatic logic Domino circuit Switch-signal theory
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Variable Relation Parametric Model on Graphics Modelon for Collaboration Design 被引量:1
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作者 董玉德 赵韩 李延锋 《Journal of Donghua University(English Edition)》 EI CAS 2005年第1期45-49,共5页
A new approach to variable relation parametric model for collaboration design based on the graphic modelon has been put forward. The paper gives a parametric description model of graphic modelon, and relating method f... A new approach to variable relation parametric model for collaboration design based on the graphic modelon has been put forward. The paper gives a parametric description model of graphic modelon, and relating method for different graphic modelon based on variable constraint. At the same time, with the aim of engineering application in the collaboration design, the autonmous constraint in modelon and relative constraint between two modelons are given. Finally, with the tool of variable and relation dbase, the solving method of variable relating and variable-driven among different graphic modelon in a part, and double-acting variable relating parametric method among different parts for collaboration are given. 展开更多
关键词 graphics modelon PARAMETERIZATION VARIABLE collaboration design.
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The Design of Water-reusing Network with a Hybrid Structure Through Mathematical Programming 被引量:4
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作者 刘永忠 段海涛 冯霄 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第1期1-10,共10页
A new design method for a water-reusing network, with a hybrid structure, to reduce the complexity of the network and to minimize freshwater consumption, is proposed. The unique feature of the methodology proposed .i... A new design method for a water-reusing network, with a hybrid structure, to reduce the complexity of the network and to minimize freshwater consumption, is proposed. The unique feature of the methodology proposed .in this article is to control the complexity of the water network by regulation of the control number in a water-reusing system. It combines the advantages of a conventional water-reusing network and a water-reusing net work with internal water mains. To illustrate the proposed method, a single contaminant system and a multiple contaminant system serve as examples of the problems. 展开更多
关键词 water-reusing network internal water main hybrid structure OPTIMIZATION
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Architectural Teaching and Design Computing: A Didactic Experience in a Brazilian Architecture Course 被引量:1
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作者 Femando Tadeu de Araujo Lima 《Journal of Civil Engineering and Architecture》 2018年第1期51-58,共8页
In the last years, architectural practice has been confronted with a paradigm shift towards the application of digital methods in design activities. In this regard, it is a pedagogic challenge to provide a suitable co... In the last years, architectural practice has been confronted with a paradigm shift towards the application of digital methods in design activities. In this regard, it is a pedagogic challenge to provide a suitable computational background for architectural students, to improve their ability to apply algorithmic-parametric logic, as well as fabrication and prototyping resources to design problem solving. This challenge is even stronger when considering less favored social and technological contexts, such as in Brazil, for example. In this scenario, this article presents and discusses the procedures and the results from a didactic experience carried out in a design computing-oriented discipline, inserted in the curriculum of a Brazilian architecture course. Hence, this paper shares some design computing teaching experiences and presents some results on computational methods and creative approaches, with a view to contribute to a better understanding about the relations between logical thinking, mathematics and architectural design processes. 展开更多
关键词 Architectural design teaching design computing didactic experience.
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Sliding mode robust controller for automatic rectification of shield machine 被引量:8
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作者 岳明 孙伟 魏建 《Journal of Central South University》 SCIE EI CAS 2011年第2期536-541,共6页
According to the actual engineering problem that the precise load model of shield machine is difficult to achieve,a design method of sliding mode robust controller oriented to the automatic rectification of shield mac... According to the actual engineering problem that the precise load model of shield machine is difficult to achieve,a design method of sliding mode robust controller oriented to the automatic rectification of shield machine was proposed. Firstly,the nominal load model of shield machine and the ranges of model parameters were obtained by the soil mechanics parameters of certain geological conditions and the messages of the self-learning of shield machine by tunneling for previous segments. Based on this rectification mechanism model with known ranges of parameters,a sliding mode robust controller was proposed. Finally,the simulation analysis was developed to verify the effectiveness of the proposed controller. The simulation results show that the sliding mode robust controller can be implemented in the attitude rectification process of the shield machine and it has stronger robustness to overcome the soil disturbance. 展开更多
关键词 shield machine RECTIFICATION sliding mode ROBUST upper bound
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