非正交网格上满足极值原理的扩散格式

构造了非正交网格上扩散方程新的非线性单元中心型有限体积格式,证明了该格式满足离散极值原理,且在适当条件下具有强制性、以及在离散H1范数下解的有界性和一阶收敛性.     

手性Salen(Co)(OAc)催化胺解动力学拆分外消旋末端的环氧化物

报道了以邻苯二甲酰亚胺作亲核试剂, 在手性催化剂salen(Co)(OAc)作用下动力学拆分外消旋末端环氧化物, 得到较高光学活性的末端环氧化物, 同时也得到了中等光学活性的N-保护的1,2-胺醇化合物. 该拆分反应所用催化剂易得, 且原料价廉, 反应无需惰性气体保护.     

测量玻璃耐磨性的浊度仪

介绍新研制的TM—100浊度仪的测量原理,叙述了浊度仪在双光路系统、光谱校正及电子运算电路方面的特点。透过率测量精度在±1％以内,浊度精度优于±5％。     

加氢处理催化剂的制备和表征 Ⅰ.MoNiP/Al2O3催化剂的制备及助剂的作用

 采用专利方法制备出一种新型的γ－Al2O3,并以其为载体,制备出加氢处理催化剂MoNiP／Al2O3．用PAS－CA,XPS,DRS,TPR和微型反应色谱等技术对γ－Al2O3和催化剂进行了表征,考察了Ni和P两种助剂的作用．结果表明,γ－Al2O3具有较大的孔径,集中的孔分布和较高的机械强度;活性金属Mo在γ－Al2O3表面上的化学分散量（分散阈值）可达5．04～5．82μmol／m2．因而特别适合用作高活性加氢处理催化剂的载体．引入的Ni主要是同Mo／Al2O3催化剂表面上较稳定的金属－载体相互作用复合物反应,并生成类NiMoO4化合物;在MoNi／Al2O3催化剂中引入P,有利于抑制四面体配位结构的物种Mo［T］,增加八面体配位结构的物种Mo［O］,改善催化剂的还原性能,从而提高催化剂的加氢处理活性．助剂Ni和P的最佳含量分别为w（Ni）＝4．0％和w（P）＝2．6％．     

UNCONDITIONAL STABLE DIFFERENCE METHODS WITH INTRINSIC PARALLELISM FOR SEMILINEAR PARABOLIC SYSTEMS OF DIVERGENCE TYPE

The general finite difference schemes with intrinsic parallelism for the boundary value problem of the semilinear parabolic system of divergence type with bounded measurable coefficients is studied. By the approach of the discrete functional analysis, the existence and uniqueness of the discrete vector solutions of the nonlinear difference system with intrinsic parallelism are proved. Moreover the unconditional stability of the general difference schemes with intrinsic parallelism justified in the sense of the continuous dependence of the discrete vector solution of the difference schemes on the discrete initial data of the original problems in the discrete W_2~(2,1) (Q△) norms. Finally the convergence of the discrete vector solutions of the certain difference schemes with intrinsic parallelism to the unique generalized solution of the original semilinear parabolic problem is proved.     

带对流项的渗流型方程的显格式

１．引言　假设有一种不可压流体在一均匀的、各向同性的刚性多孔柱形介质中流动,流动沿着与水平方向成ａ角进行,则可用下述方程描述其中λ＝ｓｉｎα,ｕ表示介质的含湿度．λ＝０,即表示沿水平方向流动,它和λ≠０的情形分别称为无对流项和有对流项的渗流方程．它们可分别写成下面一般的形式：　渗流型方程是退化抛物型方程,由于它可有退化点（使二阶导数项系数为零的点）,它与正规抛物型方程有很大区别．正规抛物型方程有充分光滑的古典解,渗流方程则不然．即使初值充分光滑,也不能保证渗流方程有光滑的解．实际上,渗流方程可有…     

Photocatalytic/Cu‐Promoted C−H Activations: Visible‐light‐Induced ortho‐Selective Perfluoroalkylation of Benzamides

A visible‐light‐induced and copper‐promoted perfluoroalkylation of benzamides was successfully developed under the assistance of an 8‐aminoquinoline directing group. It provides a straightforward method for the synthesis of ortho‐perfluoroalkyl‐substituted benzoic acid derivatives. The reaction employs a cheap organic dye eosin Y as the photoredox catalyst and is run under the irradiation of a 26 W fluorescent LED light bulb.     

液体自由晃动的数值分析

本文对常重条件下自旋容器内液体的对称和任意阶反对称晃动建立了边界元算法，引入了两种调和函数以确定边界元系数矩阵的主对角元，并且提出了一种对计算机程序的正确性和数值解近似程度的考核方法。