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关键词： Biological Transport   Computer Simulation   Humans   Inhalation   Lung   Models   Biological  

摘要： A dynamic single-path mathematical model was developed that is capable of analyzing detailed deposition patterns of inhaled particles in human lungs. Weibel's symmetric lung morphology was adopted as the basic lung structure, and detailed transport processes were evaluated numerically using the fully implicit procedure. Deposition efficiencies by specific mechanisms were individually examined for accuracy and new empirical formulas were incorporated whenever appropriate. Deposition in the alveolar region was divided into deposition fractions in the alveolar duct and alveoli, considering active transport processes between the two regions. The deposition fractions were obtained for each airway generation, serial lung volumetric compartments, and conventional three-compartment anatomic lung regions. In addition, the surface dose and cumulative deposition with time were analyzed. The results showed excellent agreement with available experimental data. The present model provides an improvement from the previously reported models and can be used as a tool in assessing internal dose of inhaled particles under various inhalation conditions.

关键词： 西方经济学   理论问题   数学分析  

摘要： 本文应用数学方法对高鸿业主编《西方经济学》(第三版)中的若干理论问题进行分析。

关键词： 系统分析   数学分析   农户经营   中华人民共和国  

摘要： 最近,读了我国青年学者韩喜平的《中国农户经营系统分析》一书后,印象很深.从家庭联产承包责任制到农户多种经营模式的出现,是我国改革开放以后的新生事物,系统分析其发展的形势和趋势,具有学术价值和实际意义,也有理论上的创新.

关键词： 厂商   商人   SWG   Secure Computing   Gartner   魔力   象限   矩阵   数学分析   领导者  

摘要： 顶级网络设备提供商 Secure Computing Corporation 的SWG 产品 Webwasher 在全球 SWG 厂商魔力矩阵中处于领导者象限,并且全球仅有两家厂商进入该领导者象限。Gartner 定义的 SWG 即 Web 安全网关的作用是当用户进行互联网通讯时,能够过滤恶意软件/恶意代码,并能强制使用者遵从公司访问策略的设备。为了达到这些要求,SWG 至少需要具备 URL 过滤、恶意代码侦测及清除、对基于 Web 应用程序的访问控制,如对即时聊天工具(IM)的控制等功能。综合保障企业网关安全是 Secure Computing 的一贯目标。作为此目标的一部分,Webwasher 结合了业内领先的信誉系统TrustedSource,为 URL、域和 IP 提供了基于来源的信誉评分,

ISBN: (纸本)9787040211993

关键词： 中学生   数学问题   数学分析   数学思考   情境设置   教学实践   生活化   自悟自得  

摘要： 我们的理念新课程强调数学教学要从学生已有的生活经验出发,让学生亲身经历将实际问题抽象成数学模型并进行解释与应用的过程。我们经过多次教学尝试和专家指导

关键词： 搜狐   博客   矩阵   数学分析   张朝阳   搜狗输入法  

摘要： "我们现在重新开始恢复了。"张朝阳说,"就像经过了一个长征,快要到达延安,现在的搜狐开始进入战略反攻阶段。"

关键词： tumor growth   free boundary problems   bifurcation   asymptotic stability   multiscale models  

摘要： In the last four decades, various cancer models have been developed in which the evolution of the densities of cells (abnormal, normal, or dead) and the concentrations of biochemical species are described in terms of differential equations. In this paper, we deal with tumor models in which the tumor occupies a well-defined region in space;the boundary of this region is held together by the forces of cell-to-cell adhesion. We shall refer to such tumors as "solid" tumors, although they may sometimes consist of fluid-like tissue, such as in the case of brain tumors (e.g. gliomas) and breast tumors. The most common class of solid tumors is carcinoma: a cancer originating from epithelial cells, that is, from the closely packed cells which align the internal cavities of the body. Models of solid tumors must take spatial effects into account, and are therefore described in terms of partial differential equations (PDEs). They also need to take into account the fact that the tumor region is changing in time;in fact, the tumor region, say Omega(t), and its boundary Gamma(t), are unknown in advance. Thus one needs to determine both the unknown "free boundary" Gamma(t) together with the solution of the PDEs in Omega(t). These types of problems are called free boundary problems. The models described in this paper are free boundary problems, and our primary interest is the spatial/geometric features of the free boundary. Some of the basic questions we shall address are: What is the shape of the free boundary? How does the free boundary behave as t --> infinity? Does the tumor volume increase or shrink as t --> infinity? Under what conditions does the tumor eventually become dormant? Finally, we shall explore the dependence of the free boundary on some biological parameters, and this will give rise to interesting bifurcation phenomena. The structure of the paper is as follows. In Secs. 1 and 2 we consider models in which all the cells are of one type, they are all proliferating ce

关键词： 《数学分析》   教学改革   成人学习  

摘要： 《数学分析》课是成人高等教育师范类三年制专升本数学专业的基础课程,在课程目标、课程结构、教学内容、思想方法、评估检查等方面都有别于其他课程。本文运用亚历山大框架理论分析该课程的问题,并依据勒梅泰、布鲁纳和刘易斯的理论观点,探讨该课程改革的基本思路。

关键词： 集中监控   网络视频   维尔特   矩阵   监控软件   数学分析   集中监控系统   网络传输技术  

摘要： 在安防监控行业中,目前我们遇到了不少关于网络视频集中管理的问题:如何在日益扩大的系统监控点的DVR/DVS等前端采集设备进行简捷方便的日常分级管理和权限控制?如何满足系统向网络化、集中化方向发展?如何充分利用已有的设备,保护用户已有的投资?如何将其他的子系统,如报警系统、门禁控制系统等平滑地集成到新一代网络监控指挥系统上来?如何让系统具备更好的灵活性,能够在遇到突发情况,有更强的应急反应能力?为解决这些问题,网络集中监控软件应运而生。