流体力学新型通用函数Y的变分有限元分析

本文应用通用函数Y及其变分原理,为求解具有自由面流动问题提出了一种新方法。将物理平面变换成映象平面。在映象平面上,引出通用函数Y,并且写出关于Y的变分原理。用这个变分原理及有限元法求解自由面流动可克服边界未知的困难。文中以水坝闸门出流问题为例进行了计算,结果表明,该方法是非常有效的。     

基于NURBS方法的转子表面造型技术

采用双三次NURBS方法对某型号转子进行几何造型,对造型过程中出现的曲面延伸、求交和裁剪等问题进行了研究.根据叶片的形状特征,以曲线的几何形式为基础,提出了一种简单实用的曲线曲面延伸方法,实现了切矢量连续的叶片型面的延伸.对于两相交面分别为自由曲面和解析曲面的求交问题,提出了一种简化的跟踪算法,实现了转子叶片型面和圆台面的准确求交和裁剪,从而实现转子精确的几何造型.     

艺术创意的设计素描

设计素描还没有明确的界定 ,但它具有艺术想象、塑造新的形象、设计素描者的“心中的画”的特点和内涵 ;要使设计素描有创意 ,就应该有理性的结构、构图和取于自然物的素材 ,并正确地运用点、线和面的组合     

论《长生殿》的表层叙事与深层悲剧意蕴

以洪?的真情观为切入点,交互采用文献研究和接受美学的分析方法,对《长生殿》借离合之情写兴亡之感的悲剧叙事形态进行了深入阐释。洪?以"至情"为标举,将不会触犯时忌的李杨情缘作为戏剧的表层叙事,而深层的情感潜流则是被强化了的历史兴亡感,从而使得时代性的秘密情感——汉族文士被压抑在心底深处的亡国之痛得到了淋漓尽致的宣泄。     

逆向工程特征参数提取技术研究

逆向工程是从已有实物的测量数据点中提取其特征参数进行模型重建的过程,特征参数的提取是逆向工程的关键技术之一。该文提出了一种新的回转面特征参数提取算法,将蚁群算法应用在逆向工程的特征参数优化过程中,首先建立回转面特征参数提取数学模型,然后运用蚁群算法实现过程优化,从而提取出特征参数,实现回转面图形重建,最后通过实例验证了该算法的有效性,该算法提高了特征参数提取精度和效率,适用于空间任意位置回转面的特征参数提取。     

基于相空间形状分析预测房颤终止

识别和描述房颤有可能自发终止还是持续,不仅可以更好地了解心律不齐发作和终止的机制,还可以更有效地治疗持续房颤。本文从非线性角度提取房颤信号特征并预测其能否自发终止。先重建心电信号的相空间,获取相空间中指定庞加莱截面上的点,然后基于形状分析提取刻画庞加莱面上相似点对相对数量的参数ρ,最后基于ρ来分类非终止房颤和可终止房颤。实验研究了一个由Holter心电信号组成的包括训练集和测试集的房颤数据库,结果表明:本文提出的特征参数ρ可正确分类90%的测试集。可见,该方法能从Holter心电信号有效地预测房颤的自发终止。     

高斯定理的理解与应用

文章论述了高斯定理源于库仑定律，依赖于场强叠加原理，场强通量与场线通量均遵从高斯定理；高斯面上的场强是其内外所考虑的电荷产生的合场强；构建体系高斯面，局部高斯面求解场强问题。     

Estimating Contaminant Dose for Intermittent Dermal Contact: Model Development, Testing, and Application

Assessments of aggregate exposure to pesticides and other surface contamination in residential environments are often driven by assumptions about dermal contacts. Accurately predicting cumulative doses from realistic skin contact scenarios requires characterization of exposure scenarios, skin surface loading and unloading rates, and contaminant movement through the epidermis. In this article we (1) develop and test a finite-difference model of contaminant transport through the epidermis; (2) develop archetypal exposure scenarios based on behavioral data to estimate characteristic loading and unloading rates; and (3) quantify 24-hour accumulation below the epidermis by applying a Monte Carlo simulation of these archetypal exposure scenarios. The numerical model, called Transient Transport through the epiDERMis (TTDERM), allows us to account for variable exposure times and time between exposures, temporal and spatial variations in skin and compound properties, and uncertainty in model parameters. Using TTDERM we investigate the use of a macro-activity parameter (cumulative contact time) for predicting daily (24-hour) integrated uptake of pesticides during complex exposure scenarios. For characteristic child behaviors and hand loading and unloading rates, we find that a power law represents the relationship between cumulative contact time and cumulative mass transport through the skin. With almost no loss of reliability, this simple relationship can be used in place of the more complex micro-activity simulations that require activity data on one- to five-minute intervals. The methods developed in this study can be used to guide dermal exposure model refinements and exposure measurement study design.     

室内设计中点线面要素的应用研究

“设计”是一个经常使用的概念,设计是在明确目的指导下的有意识的创造。室内设计是人们在满足自身需求的基础上对建筑的内部空间进行合理的功能划分、技术创新,以及艺术上的审美观的综合设计。点、线、面是作为构成抽象形态造型的要素,空间构成的基本单位。在室内设计中,点、线、面处处可见,它们之间相互影响、相互陪衬、相互烘托、相互存在、相互作用。文章从室内设计的风格、室内陈设的研究出发,对室内设计中点、线、面的运用进行思考分析。     

Sensitivity studies of air scattered neutron dose from particle accelerators

Sensitivity analysis of air scattered neutron dose at several distances from a particle accelerator with respect to shield thickness and neutron yield distributions has been carried out. We illustrate the successful use of Response Surface Methodology in studying the behaviour of the sensitivity coefficients for main effects and interaction terms. A comparison of the full six factor design and the orthogonal Central Composite Design has been made. The overhead shield is found to be the most sensitive parameter followed by the high energy part of the neutron energy distribution.