小梁现象的社会经济思考

以山西省河津市小梁乡为代表,研究了因建筑业的发展壮大而产生的社会经济空心化现象,分析了其形成原因,并提出了解决措施,以期引起大家对这一社会经济现象的关注,开展更深层次的研究。     

Stabilization techniques for spectral methods

We introduce a stabilized treatment of spectral methods. The condition number of the spectral systems is highly improved. Elliptic and biharmonic problems are considered. Suitable interpolants in the case of inhomogeneous Dirichlet boundary conditions are presented. For a direct solver the improvements with respect to rounding error propagation are numerically demonstrated.     

Reconstruction of a discontinuous function from a few fourier coefficients using bayesian estimation

The goal of this paper is the application of spectral methods to the numerical solution of conservation law equations. Spectral methods furnish estimates of the firstn Fourier coefficients of the solution. But since the solutions of conservation law equations can have discontinuities, the estimate of the solution by summing the firstn terms of the Fourier series will haveO(1/n) error, even if the Fourier coefficients are known to high accuracy. But if the solution could be accurately reconstructed from its Fourier coefficients, spectral methods could be used effectively in these problems. A method for doing this is to assume a probability distribution for functions. Functions which are smooth away from the discontinuity are assumed to be likely, and those which are not smooth away from the discontinuity are assumed to be unlikely. Then a reconstruction algorithm is chosen by minimizing the expected error over all algorithms. It is possible to put the smoothness assumptions mentioned earlier into an infinite-dimensional Gaussian probability distribution, and then the minimum-error algorithm is well-known and fairly simple to construct and apply. If the Fourier coefficients of the reconstructed function are known exactly, then this approach gives very good results. But when used with Fourier coefficients obtained from a spectral approximation to Burgers' equation, the results were much less impressive, probably because the coefficients were not known very accurately. It is possible to construct filters that reconstruct a function using Legendre or Chebyshev coefficients for information instead Fourier coefficients. It is found that the performance of these filters is similar to the Fourier case.     

化工生产中的“界面”现象对工艺设备的影响

分析了化工生产过程设备、管道中存在的各种“界面”现象及其影响，并提出相应对策。     

单晶高温合金定向凝固过程中初生碳化物的上浮现象SCIEI

本文在一种抗热腐蚀单晶镍基高温合金平面及胞状液-固界面定向凝固条件下,发现了初生碳化物(TiC)的上浮现象并分析了其形成原因。     

Na2S-SO2反应体系中H2S产生的过饱和态分析

向Na2S溶液中通入低浓度SO2气体以生成H2S，H2S从液相中逸出时，存在一突跃现象。本文根据这一现象，结合Y．T．Shah等提出的吸收－反应－解吸体系中过饱和态存在的条件，通过理论分析，得出在Na2S-SO2-H2S4反应体系中H2S解吸存在过饱和现象。     

氯代邻硝基甲苯精制方法的改进

文章讨论了用精馏和熔融结晶粗制氯代邻硝基甲苯的工艺，以及方法的改进。     

Transition phenomena of polymers in mixed solvents in the vicinity of theta conditions: Effect of preferential adsorption

Viscosimetric measurements were obtained with the ternary systems polystyrene/dioxane/methanol, polystyrene/benzene/methanol and poly(methyl methacrylate)/dioxane/cyclohexane, changing the solvent mixture composition at constant temperature. The polystyrene and poly(methyl methacrylate) systems exhibit a transition phenomenon with solvent-mixture composition in which the polymer is just above the theta condition. In the case where two theta conditions occur ((θ-intra, θ-inter) the transition point is closely related to the intramolecular theta conditions. Moreover the intramolecular theta conditions vary with the molecular weight in the region of molecular weights where the preferential adsorption also varies. This variation induces a variation of the transition point with molecular weight which obeys a formula analogous to that giving the variation of the preferential adsorption with molecular weight.     

跨文化交际中的词汇空缺现象分析

语言是跨文化交流中最主要的手段,而词汇又是语言中最活跃的因素。由于受各自民族文化的影响,在跨文化交际过程中,会出现词汇空缺现象,给跨文化交际带来障碍。研究词汇空缺现象,了解并掌握造成词汇空缺现象的原因,明白其内涵,就可以避免在跨文化交际中产生误解,减少障碍,从而使跨文化交际得以顺利进行。     

强水敏砂岩油藏水驱油相对渗透率曲线异常分析

以强水敏砂岩油藏实际岩样为例,通过水驱油渗流实验和渗流物理分析,探讨强水敏砂岩油藏水驱油过程相对渗透率曲线异常现象及其对油藏开发的影响。