ONE-DIMENSIONAL NONUNIFORM TEMPERATURE FLOW WITH HEAT TRANSFER BY CONVECTION

In ref.[1],V.E.Najenov studied the conditions that when the viscosity of the liquid isan exponential function of temperature,the pipe flow,having steady heat transfer,is one-dimensional and with nonuniform temperature.For plane canal circular pipe he stillstudied the velocity and the temperture fields.In this paper,the author presents two new methods for solving the same problem.Themethod as in ref.[1]may be regarded as the natural branch of the methods of this paper.One of our new methods only can solve the same problem as in ref.[1]and the complexdegree of its computing process is nearly the same as that in ref.[1].But the other can gobeyond the studying scope of ref.[1],namely,for the case that the curvatures ofcircumference of the cross section of the pipe are not equivalent everywhere,the problemmay also be solved.     

ON PERFECTLY STRESS FIELD AT A MIXED-MODE CRACK TIP UNDER PLANE AND ANTI-PLANE STRAIN

In [1],under the condition that all the perfectly plastic stress components at a crack tipare functions of θ only,making use of equilibrium equations.stress-strain rate relations,compatibility equations and yield condition,Lin derived the general analytical expressionsof the perfectly plastic stress field at a mixed-mode crack tip under plane and anti-planestrain.But in [1] there were several restrictions on the proportionality factor λ in thestress-strain rate relations,such as supposing that λ is independent of θ andsupposing that λ=c or cr~(-1).In this paper,we abolish these restrictions.The cases in [1],λ=cr(?)(n=0 or-1)are the special cases of this paper.     

THE APPROXIMATE SOLUTION OF THE SELF-SIMILAR PROBLEM FOR RADIAL FLOW OF NON-NEWTONIAN FLUIDS THROUGH POROUS MEDIA

In this paper, we study the approximate solution of the self-simikar problem for radial flow of non-Newtonian fluids through porous media. Assuming that the fluids obey the exponential function law, we obtain an exact solution for the exponent n=0 and compare it with the approximate solution in ref.[1]. For n>1 and n<1, we obtain respectively approximate solutions. Some exampls are presented.     

新题征展(63)

A　题组新编1 .( 1 )动点 M( x,y)满足( x - sinα) 2 + ( y - cosα) 2 =| xsinα+ ycosα- 1 | ,判断动点 M的轨迹类型 ;( 2 )动点 M( x,y)满足( x - sinα) 2 + ( y - cosα) 2 =| xsinα+ ycosα- 2 | ,判断动点 M的轨迹类型 ;( 3)动点 M( x,y)满足( x - sinα) 2 + ( y - cosα) 2 =2 | xsinα+ ycosα- 2 | ,判断动点 M的轨迹类型 ;( 4 )动点 M( x,y)满足2 ( x - sinα) 2 + ( y - cosα) 2 =| xsinα+ ycosα- 2 | ,判断动点 M的轨迹类型 .2 .( 1 )过点 P( 1 ,2 )的直线与 x、y轴的正半轴分别交于点 A、B,试求 S△ AOB 的最小…     

线性参数激励问题的周期解及过渡曲线

本文用改进的变形参数法求得了在一般情形下，一类线性参数激励问题的周期解过渡曲线。     

保守系统弱非线性振动问题的插值摄动解法

用插值摄动法求得了一类保守系统奇次弱非线性振动问题的一级近似解，精度好，甚至比多尺度法还更好，计算过程简单。     

新题征展(63)

A 题组新编 1.(1)动点M(x,y)满足 √(x-sina)2 (y-cosa)2=│xsina ycosa-1│,判断动点M的轨迹类型;     

基于邻域覆盖约简的层次化规则学习算法

在大数据环境下的分类学习中，随着描述样本语义信息的丰富，数据的类别空间结构存在着层次化。然而，现有分层分类算法缺乏可解释性，为此本文提出了一种基于邻域覆盖约简的层次化规则学习算法。该算法框架主要包括：（1）定义了面向层次化结构数据的邻域覆盖约简模型；（2）定义了层次邻域系统中覆盖元的依赖度；（3）提出了一种基于覆盖元依赖度的层次化规则学习前向搜索算法。最后，实验表明本文所提算法的分类性能较优且具有较好的可解释性。     

基于生态位视角城市对台旅游竞争力评价指标体系构建

城市旅游竞争力是在不断发展和变化的,因此,借鉴生态位理论评价城市对台旅游竞争力,在国内外研究成果的基础上,分析对台旅游竞争力生态位的影响因素,然后通过德尔菲法和专家咨询法构建了城市对台旅游竞争力生态位评价指标体系,最后,通过层次分析法计算出各层级指标的权重。研究得出,城市对台旅游竞争力生态位评价指标主要包括竞争实力、竞争潜力和竞争环境三方面,竞争实力的权重最大,其次是竞争潜力和竞争环境;竞争实力主要包括市场占有、产业结构和接待能力三方面,竞争潜力主要包括资源禀赋、经济条件和人力资源三方面,竞争环境包括自然环境、社会环境和区位条件三方面。以期在评价城市对台旅游竞争力时不仅能对城市的竞争力现状进行评价,更能对城市旅游竞争力的发展趋势进行预测。