钙钛矿型催化剂LaCoO_3的冷冻干燥制法

冷冻干燥是先使溶液骤冷而冻结后,再置低温低压下将溶剂升华除去,最后得到干燥物质的方法。它是本世纪初兴起的一门新兴技术,起初用于食品、医药和生物制品的干燥和保藏。从六十年代起,开始用来制备金属和合金粉末、陶瓷材料以及催化剂等。直用这种方法,Landsberg制得了超细钨粉和钨铼合金粉末,Schnettler制取了Al_2O_3陶瓷粉末。Tseung,Johnson,戎晶芳等又用这种方法分别制得了掺     

Upwind finite difference method for miscible oil and water displacement problem with moving boundary values

The research of the miscible oil and water displacement problem with moving boundary values is of great value to the history of oil-gas transport and accumulation in the basin evolution as well as to the rational evaluation in prospecting and exploiting oil-gas resources. The mathematical model can be described as a coupled system of nonlinear partial differential equations with moving boundary values. For the twodimensional bounded region, the upwind finite difference schemes are proposed. Some techniques, such as the calculus of variations, the change of variables, and the theory of a priori estimates, are used. The optimal orderl2-norm estimates are derived for the errors in the approximate solutions. The research is important both theoretically and practically for the model analysis in the field, the model numerical method, and the software development.     

NUMERICAL SIMULATION OF OIL MIGRATION-ACCUMULATION OF MULTILAYER AND ITS APPLICATION

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三维动边值问题的迎风差分方法

可压缩可混溶油、水三维渗流动边值问题的研究,对重建盆地发育中油气资源运移、聚集的历史和评估油气资源的勘探与开发有重要的价值, 其数学模型是一组非线性耦合偏微分方程组的动边值问题. 该文对有界域的动边值问题提出一类新的二阶修正迎风差分格式, 应用区域变换、 变分形式、能量方法、差分算子乘积交换性理论、高阶差分算子的分解、微分方程先验估计的理论和技巧, 得到了最佳 $l^2$ 误差估计结果. 该方法已成功应用到油资评估的数值模拟中. 它对这一领域的模型分析, 数值方法和软件研制均有重要的价值.     

ON A NEW KIND OF METHODS TO SOLVE THE PLANE PROBLEMS OF TWO-PHASE FLOW THROUGH POROUS MEDIA

This paper presents a new kind of method for solving the planeproblems of two-phase flow in porous media.The ellipticalpartial differential equation for pressure distribution is sol-ved by the finite element method,and then the semi-analyticalsolution for pressure gradient is used to determine the new sa-turation field according to the existing exact formula describ-ing the saturation propagation along the streamlines.The maindistinguishing feature and advantage of this kind of method arethe ability to overcome the numerical dispersion which is inhe-rent in the ordinary numerical simulation methods.and thereby,to give a precise and clear-cut position of the saturation dis-continuity in the water-oil displacement front.moreover.thesaturation equation,which should commonly be solved simultan-eously or alternatively with the pressure equation,is complete-ly avoided,so that the computing time is greatly reduced.     

煅烧制度对Lu2Ti2O7粉体生长形貌的影响

采用熔盐法制备Lu2Ti2O7粉体,研究了不同煅烧工艺对粉体形貌的影响,确定了适用于Lu2Ti2O7粉体合成的工艺条件,并在利用XRD、SEM等方法分析表征样品的基础上,提出了初步的粉体形貌生长转变机制。实验结果表明:形核速率和生长速率对粉体的颗粒尺寸和形状影响很大,过快的形核速率和生长速率有利于多面棱柱状晶粒的生长,反之则有利于八面体形状的晶粒生长。     

离子伯恩斯坦波对低杂波驱动电流影响的研究

利用改进的二维Fokker-Planck方程和低杂波射线轨迹程序研究了在低杂波和离子伯恩斯坦波协同作用下低杂波的功率沉积分布、驱动电流分布。数值结果显示在两波协同作用下低杂波驱动非感应电流的效率得到了很大的改善。     

Parallel arithmetic numerical simulation and application of secondary migration-accumulation of oil resources

From such actual conditions as the effects of characteristics of miltilayer petroleum geology and permeation fluid mechanics, a new numerical model is put forward and coupling splitting-up implicit interactive scheme is formed. For the actual situation of Dongying hollow ( four-layer ) and Tanhai region ( three-layer ) of Shengli Petroleum Field, the numerical simulation test results and the actual conditions are coincident.     

多层油资源运移聚集的数值模拟和实际应用

研究了三维问题的石油地质和渗流力学特征。提出了数学模型,构造了新的算子分裂隐式迭代格式,并成功地对胜利油田东营凹陷(厚层)和惠民凹陷(多层)带断层和通道的实际问题进行了大规的数值模拟计算。计算结果在油藏位置等方面和实际情况相吻合,完整地解决了这一石油地质和渗流力学的国际着名问题。