The Influence of Hygroscopic Materials on the Fluctuation of Relative Humidity in Museums Located in Historical Buildings

ABSTRACT

The preservation of artefacts in museum collections is profoundly affected by fluctuations in temperature and, especially, relative humidity (RH). Since the late nineteenth century, many studies have been carried out on the best way to control hygrothermal conditions. In old buildings located in maritime temperate climate zones (such as Portugal) with strong thermal inertia, and which have low ventilation rate (relative to the volume and number of visitors), daily and seasonal hygroscopic inertia may help to assure the maintenance of RH stabilization conditions. The use of expensive active systems may be minimized through the passive behaviour of internal finishing building materials. This work presents the results of an experimental laboratory study conducted in a flow chamber to demonstrate the enormous potential of hygroscopic materials in stabilizing interior relative humidity. Based in these results and in-situ monitoring in a museum housed in a building, located in Porto, with a typical construction of the 1950s (granite masonry and reinforced concrete slabs), a numerical analysis was done to quantify the influence of hygroscopic materials in stabilizing the interior relative humidity.     

非惯性参照系中的Lagrange方程

从非惯性参照系中的惯性力表达式出发，找出与之相对应的广义势函数U’，进一步写出与之相对应的类Lagrange函数表达式L″，从而推导出在非惯性参照系中的第二类Lagrange方程和保守力系的Lagrange方程，并通过实例说明在非惯性参照系中Lagrange方程的应用，从分析力学的角度提出了求解非惯性参照系中的动力学问题的一种方法。     

基于小型无人直升机的三维建模成像系统设计

对于大角度、大范围、复杂场景的快速扫描成像系统,除了要进行任意运动和动态采集建模外,还要对激光传感器的姿态和位置进行实时精确的描述.基于此要求,文中构建了一种基于小型无人直升机机载激光扫描传感器的三维建模成像系统,并设计了一种分步式串级滤波算法,将激光测距传感器得到的距离信息,与小型无人直升机惯性导航系统解算的姿态与位置数据进行融合,实现空间扫描点到基准坐标系的映射,并完成2D行扫描到3D空间的扩展,建立现实世界的3D数字模型.     

一种发动机液力悬置动特性研究

基于流体力学理论,研究发动机液力悬置惯性通道内阻尼力,建立一种液力悬置力学模型和数学模型,进行动特性仿真,从流体力学的角度分析了液力悬置的结构参数对其动态特性的影响。     

三线摆测量刚体转动惯量及其误差分析

本文研究了三线摆法测量刚体转动惯量的误差影响因素并对误差的来源和原因进行了分析,在此基础上对实验操作提出了一些改进的方法,以提高实验的精度。     

A Nonlinear Dynamical Theory of Non-Classical Plates

In this paper, a new nonlinear formulation of plates, including shear and rotatory inertia and transverse normal stress effects, is developed by means of general assumptions, of which the von Karman-type formulation and some thick plate theories are special cases. To keep the formulation fairly general, the problem addressed in this paper simultaneously includes: the effects of shear deformation according to the geometric deformation similarity of the cross-section, the rotatory inertia, and the transverse normal stress. The three-dimensional compatible equations are applied to derive the basic equations. Numerical results are given for linear and non-linear analysis of plates. This Work was supported by the Natural Science Fundation of Shanghai for Returning Scholars     

定点转动刚体打击中心研究

从刚体定点转动的动力学方程出发，推导定点转动刚体打击中心位置的普遍表达式，并通过特例加以应用。     

分析“转正”技术在速度滑冰中的应用研究

速度滑冰是一项专项技能很强的运动项目,蹬冰力是速滑技术的基础,只有运动员、教练员充分认识到蹬冰力的重要才能达到完善技术、提高成绩的目的。本文创新地提出了速滑运动中“转正”技术,并通过生物力学和实践训练成绩对比进行分析,论证了新技术的可行性,为我国速度滑冰竞技水平的提高提出建设性意见。     

一种导出洛仑兹变换的简明方法

通过二个假设实验,由光速不变原理导出了洛仑兹变换关系式,简明严谨．     

组织惰性行为初研

组织惰性行为极大阻碍了组织的快速发展与持续创新,本提出并探讨了组织惰性行为问题,包括：（１）：组织惰性行为的定义与类型特点,（２）组织惰性行为的病象表现,（３）组织惰性行为的生成原因,（４）组织惰性行为的内在生存机制,（５）克俘组织惰性行为的基本管理策略。