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“有多重”教学设计 被引量:1
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作者 王芳 陈丽岩 《黑龙江教育(小学版)》 2010年第7期46-47,共2页
教学内容:北师大版小学数学3年级上册第三单元。教材分析:本课是学生初次学习质量单位。由于质量单位比较抽象,仅靠观察是不够的,因此,教材注意引导学生通过多种实际操作活动进行感知,尤其重视对学生估计能力的培养,目的是通过... 教学内容:北师大版小学数学3年级上册第三单元。教材分析:本课是学生初次学习质量单位。由于质量单位比较抽象,仅靠观察是不够的,因此,教材注意引导学生通过多种实际操作活动进行感知,尤其重视对学生估计能力的培养,目的是通过学生的活动,建立千克、克的质量概念以及它们的进率关系,增加学生对千克和克的感性认识,并联系实际,使学生初步体验于克和克在生活中的应用。 展开更多
关键词 “有多重” 教学设计 引导学生 质量单位 教材分析 能力的培养 小学数学 北师大版
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“有多重”活动课教学实践
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作者 段华 《云南教育》 2003年第13期44-45,共2页
关键词 活动课教学 “有多重” 小学 数学 第四册 课程标准 教学建议
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“有多重”教学实录与评析
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作者 于娜 周莹心 《吉林省教育学院学报(小学教研版)》 2009年第2期123-124,127,共3页
[教学内容 人教版教材二年级下册第104—105页。 [教学过程] 一、直接导入 师:小朋友们,今天我们一起来上一节数学实践活动课:有多重。(板书课题)
关键词 “有多重” 教学实录 数学实践活动课 二年级下册 人教版教材 教学内容 教学过程 小朋友
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实践体验,让数学焕发生命活力——“有多重”实践活动案例
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作者 英瑾 郭艳丽 《小学教学(数学版)》 2017年第5期29-31,共3页
北师大版教材三年级下册“有多重”一课.主要内容是认识千克和克。为了帮助学生建立起1千克和1克的质量概念.郭老师设计了估一估、掂一掂、称一称等丰富的活动,鼓励学生通过实际操作活动进行充分的感知和体验,却不料引发了课堂上的... 北师大版教材三年级下册“有多重”一课.主要内容是认识千克和克。为了帮助学生建立起1千克和1克的质量概念.郭老师设计了估一估、掂一掂、称一称等丰富的活动,鼓励学生通过实际操作活动进行充分的感知和体验,却不料引发了课堂上的“无限风波”。 展开更多
关键词 “有多重” 实践体验 活动案例 生命活力 数学 北师大版教材 三年级下册 质量概念
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“有多重”教学设计
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作者 龙青 《云南教育》 2007年第09S期35-35,共1页
教材:义务教育课程标准实验教科书北师大版数学三年级上册第三单元。 设计思路:质量单位不像长度单位那样直观、具体,学生初次学习时更不能只靠观察得到认识。鉴于此,本节课欲通过学生称、掂、估、猜、说等一系列有效的操作活动,... 教材:义务教育课程标准实验教科书北师大版数学三年级上册第三单元。 设计思路:质量单位不像长度单位那样直观、具体,学生初次学习时更不能只靠观察得到认识。鉴于此,本节课欲通过学生称、掂、估、猜、说等一系列有效的操作活动,联系课前学生“逛”商场对质量单位的了解,使每个学生都能较深刻地认识质量单位千克、克。 展开更多
关键词 教学设计 “有多重” 义务教育课程标准 质量单位 三年级上册 实验教科书 北师大版 长度单位
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“有多重”教学设计
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作者 张学万 晏俊 《云南教育》 2006年第07S期48-49,共2页
关键词 “有多重” 教学设计 义务教育课程标准 三年级上册 实验教科书 北师大版 教学内容 数学
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借“直观”来理解“抽象”——由“有多重”一节教学引发的思考
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作者 吴玉梅 《学园》 2013年第30期150-150,共1页
数学教学的实质是数学活动的教学,数学活动的关键是让学生自己去“做”,去探索,去经历,去感受。常听到一些老师在教学“有多重”一节时抱怨学生们一点也不动脑筋,把爸爸的体重65千克错误地写成65克,他爸爸难道和一个鸡蛋一样重?... 数学教学的实质是数学活动的教学,数学活动的关键是让学生自己去“做”,去探索,去经历,去感受。常听到一些老师在教学“有多重”一节时抱怨学生们一点也不动脑筋,把爸爸的体重65千克错误地写成65克,他爸爸难道和一个鸡蛋一样重?把一枝笔的重量8克错误地写成8千克,一枝笔难道和一个大西瓜一样重?其实别抱怨学生,都是老师怕麻烦惹的祸。 展开更多
关键词 “有多重” 数学教学 抽象 数学活动 “做” 学生 抱怨 老师
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在现实情境中感受“克”与“千克”——“有多重”教学实录与评析
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作者 张李娜 朱菊 《小学数学教育》 2016年第7期122-124,共3页
教学内容:北师大版《义务教育教科书·数学》三年级下册第四单元第一课时。教学目标:1.在具体的生活情境中感受并认识质量单位克和千克,初步建立1克和1千克的观念,知道"1千克=1000克"。2.在"掂"、"估"、"称"、"找"、"... 教学内容:北师大版《义务教育教科书·数学》三年级下册第四单元第一课时。教学目标:1.在具体的生活情境中感受并认识质量单位克和千克,初步建立1克和1千克的观念,知道"1千克=1000克"。2.在"掂"、"估"、"称"、"找"、"说"等操作活动中形成丰富认识和创新意识。3.感受数学知识与生活息息相关,培养对数学学习的积极情感,体验学习成功的乐趣。 展开更多
关键词 “有多重” 教学实录 感受 现实情境 生活情境 数学知识 三年级下册 义务教育
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“有多重”教学设计
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作者 王娜 《中小学数学(小学版)》 2003年第12期30-31,共2页
关键词 “有多重” 教学设计 小学 数学教学 三年级 教学目标
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“有多重”教学设计
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作者 李丽萍 《云南教育(小学教师)》 2011年第4期28-29,共2页
教材简析: “有多重”是义务教育课程标准实验教科书人教版数学二年级下册“克和千克”这一知识点的实践活动。教材选取学生日常生活中富有情趣的“称体重”、“背一背”等活动,并结合活动渗透了一些统计的初步知识。
关键词 “有多重” 教学设计 义务教育课程标准 教材简析 二年级下册 实验教科书 实践活动 日常生活
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TRUNCATION ERROR REDUCTION METHOD FOR PLANAR CAVITY FLOW
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作者 夏健 刘超群 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2001年第2期119-123,共5页
A new so called truncation error reduction method (TERM) is developed in this work. This is an iterative process which uses a coarse grid (2 h ) to estimate the truncation error and then reduces the error on the or... A new so called truncation error reduction method (TERM) is developed in this work. This is an iterative process which uses a coarse grid (2 h ) to estimate the truncation error and then reduces the error on the original grid ( h ). The purpose is to use coarse grids to get more accurate results and to develop a new method which could do coarse grid direct numerical simulation (DNS) for more accurate and acceptable DNS solutions. 展开更多
关键词 truncation error finite difference MULTIGRID
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3-D direct current resistivity forward modeling by adaptive multigrid finite element method 被引量:9
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作者 汤井田 王飞燕 +1 位作者 任政勇 郭荣文 《Journal of Central South University》 SCIE EI CAS 2010年第3期587-592,共6页
Based on the fact that 3-D model discretization by artificial could not always be successfully implemented especially for large-scaled problems when high accuracy and efficiency were required, a new adaptive multigrid... Based on the fact that 3-D model discretization by artificial could not always be successfully implemented especially for large-scaled problems when high accuracy and efficiency were required, a new adaptive multigrid finite element method was proposed. In this algorithm, a-posteriori error estimator was employed to generate adaptively refined mesh on a given initial mesh. On these iterative meshes, V-cycle based multigrid method was adopted to fast solve each linear equation with each initial iterative term interpolated from last mesh. With this error estimator, the unknowns were nearly optimally distributed on the final mesh which guaranteed the accuracy. The numerical results show that the multigrid solver is faster and more stable compared with ICCG solver. Meanwhile, the numerical results obtained from the final model discretization approximate the analytical solutions with maximal relative errors less than 1%, which remarkably validates this algorithm. 展开更多
关键词 adaptive multigrid a-posteriori error estimator unstructured mesh V-CYCLE finite element method
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Amide-linked covalent organic frameworks as efficient heterogeneous photocatalysts in water
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作者 Si Ma Ziping Li +6 位作者 Ji Jia Zhenwei Zhang Hong Xia He Li Xiong Chen Yanhong Xu Xiaoming Liu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第11期2010-2019,共10页
Semiconductor photocatalysts play an indispensable role in the photocatalytic process.Two-dimensional covalent organic frameworks(2D-COFs),as a kind of innovative photocatalyst,have garnered tremendous attention.Herei... Semiconductor photocatalysts play an indispensable role in the photocatalytic process.Two-dimensional covalent organic frameworks(2D-COFs),as a kind of innovative photocatalyst,have garnered tremendous attention.Herein,we report an amide-linked 2D-COF(COF-JLU19)with outstanding photocatalytic performance in water,designed through a multi-synergistic approach.The synergistic effects of the high porosity,photoactive framework,high wettability,and stability of COF-JLU19 led to an unprecedented enhancement in the photocatalytic activity and recyclability in water upon illumination by visible light.More importantly,amide-linked 2D-COF based electrospinning membranes were prepared,which also exhibited superior photocatalytic activity for the degradation of Rhodamine B in water with sunlight.This study highlights the potential of the multi-synergistic approach as a universal rule for developing COF-based photocatalysts to address environmental and energy challenges. 展开更多
关键词 Covalent organic frameworks Multiple synergies PHOTOCATALYSIS Porous materials Dye degradation
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Standard and Economical Cascadic Multigrid Methods for the Mortar Finite Element Methods 被引量:3
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作者 Xuejun Xu Wenbin Chen 《Numerical Mathematics(Theory,Methods and Applications)》 SCIE 2009年第2期180-201,共22页
In this paper, standard and economical cascadic multigrid methods are considered for solving the algebraic systems resulting from the mortar finite element methods. Both cascadic multigrid methods do not need full ell... In this paper, standard and economical cascadic multigrid methods are considered for solving the algebraic systems resulting from the mortar finite element methods. Both cascadic multigrid methods do not need full elliptic regularity, so they can be used to tackle more general elliptic problems. Numerical experiments are reported to suonort our theorv. 展开更多
关键词 Cascadic multigrid mortar finite elements.
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Asymptotic expansions of finite element solutions to Robin problems in H^3 and their application in extrapolation cascadic multigrid method 被引量:1
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作者 HU HongLing CHEN ChuanMiao PAN KeJia 《Science China Mathematics》 SCIE 2014年第4期687-698,共12页
For the Poisson equation with Robin boundary conditions,by using a few techniques such as orthogonal expansion(M-type),separation of the main part and the finite element projection,we prove for the first time that the... For the Poisson equation with Robin boundary conditions,by using a few techniques such as orthogonal expansion(M-type),separation of the main part and the finite element projection,we prove for the first time that the asymptotic error expansions of bilinear finite element have the accuracy of O(h3)for u∈H3.Based on the obtained asymptotic error expansions for linear finite elements,extrapolation cascadic multigrid method(EXCMG)can be used to solve Robin problems effectively.Furthermore,by virtue of Richardson not only the accuracy of the approximation is improved,but also a posteriori error estimation is obtained.Finally,some numerical experiments that confirm the theoretical analysis are presented. 展开更多
关键词 finite element Richardson extrapolation Robin problem asymptotic expansion cascadic multi-grid method
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Sensitivity Analysis of Parameters for Multi-stand Roll Forming Using a New Booting Model
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作者 曾国 来新民 +1 位作者 于忠奇 林忠钦 《Journal of Shanghai Jiaotong university(Science)》 EI 2008年第6期707-711,共5页
Multi-stand roll forming is a process that has very complicated deformation behaviour and shows significant nonlinearity.In this paper, the sensitivity analysis of parameters for multi-stand roll forming was performed... Multi-stand roll forming is a process that has very complicated deformation behaviour and shows significant nonlinearity.In this paper, the sensitivity analysis of parameters for multi-stand roll forming was performed via a new booting finite element method(FEM) model.Compared with the most of simulation, the new model is more consistent with production process and can account for the effects of roll rotating speed.Based on the model, the process of an open section channel formed with 10 passes was simulated and the sensitivity analysis was conducted with orthogonal experiment design combined FEM model.The multi-stand roll forming process can be efficiently analyzed by the new booting model.And sensitivity analysis shows the hardening exponent plays an important role in controlling the quality of the products. 展开更多
关键词 sensitivity analysis roll forming multi-stand finite element method
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EXISTENCE OF LIMIT CYCLES IN A MULTIPLY-CONNECTED REGION
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作者 ZHANG XIANG(Department of Mathematics, Naming Normal University, Naming 210097, China.) 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 1999年第2期169-172,共4页
In this paper,a conjecture about the existence of limit cycles in a multiply-connected regionproposed by Ye Yanqian is proved.
关键词 Multiply-connected region Annulus theorem Limit cycle
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SOME RATIONALITY CONDITIONS OF JOINT EFFICIENT MAPPING IN GROUP MULTI-OBJECTIVE PROGRAMMING
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作者 Jing LI Yuda HU 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2007年第4期585-591,共7页
The joint efficient ordering method is a fundamental method of ordering alternatives in group multi-objective programming problems. In this paper, the rational properties of the joint efficient mapping corresponding t... The joint efficient ordering method is a fundamental method of ordering alternatives in group multi-objective programming problems. In this paper, the rational properties of the joint efficient mapping corresponding to the joint efficient ordering method are studied, and some necessary conditions of this mapping are proven. 展开更多
关键词 group multi-objective programming joint efficient mapping joint efficient ordering method rationality condition.
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Single-polarization photonic crystal fibers with a multiplex structure
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作者 毛栋 关春颖 苑立波 《Optoelectronics Letters》 EI 2011年第1期57-60,共4页
A new kind of single-polarization photonic crystal fiber(PCF) is proposed.Two kinds of multi-component glasses and the air are selected as working materials.Through using the full vector finite element method(FEM) and... A new kind of single-polarization photonic crystal fiber(PCF) is proposed.Two kinds of multi-component glasses and the air are selected as working materials.Through using the full vector finite element method(FEM) and the perfectly matched layers(PML),the polarization-maintaining characteristic and the confinement loss of the fiber are analyzed,respectively.In addition,the single-polarization region of the fiber around 1.55 ìm is discussed.Numerical simulations show that the fiber maintains single-polarization operation within the wavelength range of 1.421-1.696μm.The birefringence can reach 6.988×10-3,and the confinement loss is as low as 0.012 dB/m when 7 layers of ring holes are arranged in the cladding at λ=1.55μm. 展开更多
关键词 Crystal structure Crystal whiskers Fibers Finite element method Laser pulses Nonlinear optics Photonic crystals POLARIZATION
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