“做中学”指导下“直线的一般式方程”的探索与思考

数学概念引入要坚决摒弃“一个定义、三项注意、疯狂练习”的做法,不能简单地从抽象定义出发,应从具体事例出发,概念引入提倡归纳式,问题驱动建议活动式,设计的问题一要面向全体,二要有明确的目标,三要由浅入深,四要难度适当.以活动驱动探究、以问题引领教学的“做中学”,先做后学,先学后教,少教多学,以学定教,以学论教,可以让学生学会学习,提升学生的数学核心素养.     

NORMAL EXPANSION THEORY FOR PENETRATION OF PROJECTILE AGAINST CONCRETE TARGET

Based on the equations which describe the dynamic behavior of material under high-velocity and high-pressure shock, corresponding equations at shock front whose surface is general space curve surface were established. For concrete material, a normal expansion theory was proposed by which some deceleration about time history of the projectile can be analytically given. This normal expansion theory is not only suitable for spherical and cylindrical-nose projectile, but also suitable for other general nose projectile, for example conical nose or ogive-nose. And it is not only suitable for perpendicular shock but also for oblique shock.     

FREE VIBRATION OF ANISOTROPIC RECTANGULAR PLATES BY GENERAL ANALYTICAL METHOD

According to the differential equation for transverse displacement function of anisotropic rectangular thin plates in free vibration, a general analytical solution is established. This general solution, composed of the composite solutions of trigonometric function and hyperbolic function, can satisfy the problem of arbitrary boundary conditions along four edges. The algebraic polynomial with double sine series solutions can also satisfy the problem of boundary conditions at four corners. Consequently, this general solution can be used to solve the vibration problem of anisotropic rectangular plates with arbitrary boundaries accurately. The integral constants can be determined by boundary conditions of four edges and four corners. Each natural frequency and vibration mode can be solved by the determinate of coefficient matrix from the homogeneous linear algebraic equations equal to zero. For example, a composite symmetric angle ply laminated plate with four edges clamped has been calculated and discussed.     

一般梯形模糊逼近算子及其在模糊运输问题中的应用

研究运输成本信息为一般模糊数的模糊运输问题.首先,在保持一般模糊数的核不变的条件下,建立一般模糊数与一般梯形模糊数的距离最小优化模型,通过求解模型得到一般模糊数的一般梯形模糊逼近算子,并给出该逼近算子具有的性质如数乘不变性、平移不变性、连续性等.然后利用该逼近算子将一般模糊运输信息表转换成一般梯形模糊运输信息表,再根据已有GFLCM和GFMDM算法得到模糊运输问题的近似最优解,最后给出具体算例分析说明方法的有效性和合理性.     

一般力学中动力系统的非线性和混沌的最新进展与展望

本文从力学的角度出发综述了摈睛为国内外在压力系统的非线线和混沌方面的主要成果和发展前景。首先，本文阐述了非线性动力系统发展的必要性，其欠，我们详细的综述了非线性振动和局部分叉，全局分叉和混沌，非线笥随机系统的振动和分叉，和某些应用基础理论问题等四个方面近期国内外的主要研究成果。     

远离跟风的陷阱

跟风产品是糟糕透顶的,搞跟风概念同样是问题重重：在潜在顾客的心智里,两家公司不可能共享相同的概念。当竞争者在潜在顾客的心智中已经有定位时,所有试图再去占据相同定位的努力都是徒劳的     

一般构形双基SAR多普勒特性分析

基于一般构形双基合成孔径雷达(SAR)的空间几何关系,分析了一般构形双基SAR的特点,给出了一般构形双基SAR回波的多普勒参数表达式。由于一般空间构形双基SAR发、收平台的运动矢量是不相等的,造成双基系统对场景中每一个点目标的成像几何结构是不同的,因此成像处理中除了需要校正距离空变量外,还需要补偿方位空变量。星机构形的实例分析验证了这种方位空变性。文中对一般构形双基SAR空变多普勒参数分析的结果为系统参数选择和二维空变补偿成像处理提供了相关的基础。     

Existence of positive solutions for a general nonlinear eigenvalue problem

Let Ω R n be a bounded domain, H = L 2 (Ω), L : D(L) H → H be an unbounded linear operator, f ∈ C(■× R, R) and λ∈ R. The paper is concerned with the existence of positive solutions for the following nonlinear eigenvalue problem Lu = λf (x, u), u ∈ D(L), which is the general form of nonlinear eigenvalue problems for differential equations. We obtain the global structure of positive solutions, then we apply the results to some nonlinear eigenvalue problems for a second-order ordinary differential equation and a fourth-order beam equation, respectively. The discussion is based on the fixed point index theory in cones.     

能源节约型技术进步下碳关税对中国经济与环境的影响——基于动态递归可计算一般均衡模型

将动态递归的可计算一般均衡方法应用于碳关税征收影响的研究,建立了测算美国征收碳关税对中国经济与环境影响的动态递归可计算一般均衡模型,并在模型中引入技术进步参数以刻画能源节约型技术进步.模型以2007年作为基年,包含37个生产部门和7个国内国外账户.应用该模型模拟了2020年起美国征收碳关税,在税率从20美元每吨碳排放到80美元每吨碳排放的13种情景下,到2030年期间对我国碳排放和经济发展的不同影响,进而测算在不同的能源节约型技术进步条件下,碳关税对我国经济与环境影响的变动.     

从客户视角研究微型付款模式对企业绩效的影响

基于客户资产理论,从客户视角研究微型付款模式影响企业绩效的机制进行研究.采用问卷设计和数据收集方式,研究共回收有效问卷2260份.通过对这2260份有效问卷进行信度和效度检验、描述性统计分析、相关分析和多元回归分析,对关于微型付款模式影响企业绩效的假设进行实证,找出客户视角微型付款模式影响企业绩效的机制.