膀胱上皮细胞的不对称单位膜结构及其在胚胎发育中的变化

膀胱上皮细胞的不对称单位膜结构及其在胚胎发育中的变化于勤李岫芬程钤丁明孝翟中和（北京大学生命科学学院，北京１００８７１）哺乳动物的膀胱上皮细胞最典型的特征之一是存在着一种特殊的不对称单位膜（ＡｓｙｍｍｅｔｒｉｃＵｎｉｔＭｅｍ－ｂｒａｎｅ简称ＡＵＭ）结...     

确定型存贮模型的系统动态描述

本文尝试用系统动态学的研究方法于存贮理论，建立确定型存贮问题的系统动态优化模型，并对模型作了数学推导。     

面向对象工程数据库管理系统O2S并发事务模型

Ｏ２Ｓ是我们在ＳＵＮ工作站上开发的一面向对象工程数据库管理。本文针对工程应用域事务的嵌套性，长时性，数据库逻辑分区性和涉及数据量大的四个显著特点，阐述了Ｓ２Ｓ的事务管理模型。对工程域事务的管理，数据库的恢复和封锁技术进行了讨论。     

构造数学模型 优化思维素质

本文根据广义数学模型的观点，阐明了利用“构造模型法”进行概念教学、定理教学与解题教学，能抓住知识的关键，突破教学难点、使学生加深对重点知识的记忆与理解，激发数学兴趣，优化思维素质，提高能力。     

一种基于耗能平衡概念的弹塑性本构模型

本文用耗散平衡方法构造了一个弹塑性本构模型，该模型包含了Ｚｉｅｇｌｅｒ模型和Ｍｉｓｅｓ模型。     

无溢流管多层流化床换热器的热态模型研究

本文对无溢流管多层流化床换热器进行了热态模型实验研究，得出了气－固两相间的界膜换热系数曲线，所得结论可供参考。     

化工原理三维实验仿真软件的设计与实现

计算机化工原理三维实验仿真软件是为提高化工原理实验总体效果而研制的。该软件以Ｗｉｎｄｏｗｓ作为开发与应用平台，采用三维图形用户界面，所用实验过程模型经充分论证和处理能严格模拟实验装置的操作及数据处理过程特性。     

A cell-based robust optimal coordinated control on urban arterial road

Process of optimizing coordinated control is divided into two stages.At the first stage,the study improves a robust optimal control model of single-point intersection to optimize cycle and split.At the second stage,the study combines all links with intersections of arterial road as a complete system,and applies cell transmission model to simulate traffic flow on urban signalized arterial road.We propose a coordinated control model based on the platform to optimize offset between adjacent intersections.Genetic algorithm is executed by MATLAB to solve the model.The performance evaluations show that the model not only effectively reduces average delay and stopping rate of vehicles on arterial road and largely enhances traffic capacity of arterial road,but also lowers the sensitivity of signal control for flow fluctuations.     

Identification of Hammerstein systems with asymmetric dead-zone nonlinearities using canonical parameterized model

A non-iterative identification method with parameterization of the unknown dead-zone is proposed for Hammerstein systems in presence of asymmetric dead-zone nonlinearities.The canonical parameterized model which is a single expression without segmentation is utilized to describe the dead-zone,based on which a universal-type parametric model can be established to approximate the entire system.This model can be established without separating the nonlinear part from the linear part.The dead-zone parameters and the coefficients in the linear transfer function can be estimated simultaneously according to the proposed algorithm.Numerical experiments are presented to illustrate the effectiveness of the proposed scheme.