Type? What Type? Further Reflections on the Extended Threshold

Michael Hensel draws a parallel between the present and a moment in the early 1990s when typology seemed poised to come to the fore. He highlights how despite a promising start this interest slipped away and was supplanted by an obsession with topography and highly complex surfaces, leading to a primacy of the individual built form over the urban.     

Stability of polydihydrosilane liquid films on solid substrates

The quality of polydihydrosilane liquid films is a key factor in the fabrication of solution-processed silicon films. This study investigates the stability of polydihydrosilane liquid films with a thickness L of ~ 40 nm on solid substrates by a comparison between the observed optical microscope images and the values of the Hamaker constant A_ALS for the air/liquid (polydihydrosilane)/solid substrate systems. A_ALS values for a series of SiO₂-based substrates were determined by adopting a simple spectrum method. We found that the micrographs of the polydihydrosilane films provide direct evidence of stability in accordance with the sign of A_ALS; a stable liquid film with A_ALS > 0 showed a continuous figure, while an unstable film with A_ALS < 0 exhibited an array of dots caused by the rupture of the film. The array of dots in the unstable liquid films has a slight orderly distribution with a period λ that is in accord with the characteristic wavelength of the undulation related to the spinodal-like decomposition in van der Waals unstable liquid.     

Nanoscale vibration characterization of multi-layered graphene sheets embedded in an elastic medium

Detailed studies on the nanoscale vibration characteristics of multi-layered graphene sheets (MLGSs) that are embedded in an elastic medium are carried out using continuum-based modelling and Generalized Differential Quadrature (GDQ) method. Natural frequencies and their associated vibration modes of practical interest of single-layered and triple-layered graphene sheets, as well as general MLGSs that are embedded in an elastic medium are established. Numerical simulations are conducted to examine the effects of van der Waals (vdW) interactions, which are present as bonding forces between the layers, on nanoscale vibration natural frequencies and their mode shapes. The results show that for a general MLGSs embedded in an elastic medium, vibration modes can in general be classified into three families - lower classical synchronized modes which are independent of van der Waals forces and are somewhat sensitive to the surrounding elastic medium, middle van der Waals enhanced modes which are largely determined by the presence of van der Waals interactions and are hence less sensitive to the changes of the surrounding elastic medium, and higher mixed modes which are combinations of classical synchronized modes and van der Waals enhanced modes. Detailed characterizations of these modes from their derived mode shapes have been achieved for the typical case of an embedded triple-layered GSs, as well as general embedded MLGSs. Effects of Winkler modulus K_W, the shear layer modulus G_b, different boundary conditions, aspect ratio β and the number L of graphene layers on nanoscale vibration properties have been examined in detail. The results presented in this paper, for the first time, provide accurate and wholesome studies and characterizations on the interesting nanoscale vibration properties of multi-layered graphene sheets embedded in an elastic medium and the results obtained will certainly be useful to those who are concerned with the dynamics of embedded graphene sheets which are increasingly being deployed for various innovative engineering applications such as nano-electro-mechanical systems (NEMS).     

Rheological properties of aqueous alumina suspensions

The aim of the present work was to investigate rheological behaviour of alumina suspensions, considering different amounts of polyvinyl alcohol (PVAL) as a binder. Three different aqueous suspensions were prepared, containing 60, 70 and 80 wt.% of alumina powder. Spinel was added as a sintering agent and Darvan 821‐A as a dispersant, in an amount of 0.08 and 0.4 wt.% of dry powder weight, respectively. The alumina suspensions flow curves were recorded and fitted satisfactorily to the power law, Herschel‐Bulkley and Bingham models. Obtained results indicate that apparent viscosity of alumina suspensions increases with increasing Al₂O₃ and polyvinyl alcohol amount.     

微型汽车发动机排气系统优化设计——基于流体数值模拟的应用研究

为了研究排气系统设计对整机的动力性、经济性及排放性能的影响,通过一维三维的数值模拟方法,分析了原排气歧管存在的排气干涉的问题,对新旧设计进行了一维模拟计算对比。利用CFD/FEM耦合方法,计算了在最大功率点排气歧管的温度分布及热应力分布。通过三维CFD计算,分析了氧传感器位置气流分布及催化转化器前端气流均匀性。制造排气系统实物并进行台架试验,结果表明整机性能有了显著的提高,并且耐久性与排放符合设计要求。     

Correlating and Predicting the Solubilities of Solid n-Alkanes in Supercritical Ethane Using Carnahan-Starling-van der Waals Model

The solubilities of some solid n-alkanes in supercritical ethane were correlated and predicted in this paper using the Carnahan-Starling-van der Waals model with a density-dependent parameter of a12. At a given temperature, the linear fit of the parameter of a12 and the density of the supercritical solvent was used for solubility correlation, resulting in an average absolute average relative deviation（AARD） of 8.68%, which was between the values of the semiempirical models and the other compressed gas models used in this article. In the linear fit of the parameter of a12 and the density of the solvent, the regressed slope m and intercept n of the linear fit can be correlated with the carbon atom number of solid n-alkanes and then the solubilities of solid n-alkanes in supercritical ethane can be predicted with the intercept n and slope m. The average AARD in solubility prediction was 26.99%.     

Condensation: Regionalism and the Room in John Yeon's Watzek House

Mary Anne Beecher's discussion of Aubrey Watzek's house extends traditional notions of regionalism to the domain of the interior. She outlines numerous ways that the local landscape and history figure as condensed renditions within rooms, surfaces and details. It is here that we find evidence of interior atmosphere developed as identity within a specific cultural and geographical context. Copyright © 2008 John Wiley & Sons, Ltd.     

724XD气象应急移动雷达车及其应用

724XD雷达是一种先进的中频相参体制的X波段脉冲多普勒天气雷达设备,能提供高时空分辨力的、连续的空中资料,性能稳定,适合车载移动使用。文章介绍了724XD雷达的组成、基本原理、产品显示和深圳市气象应急移动雷达车的组成架构、改装安装等,并简单描述了应急移动雷达车在台风“风神”过程中的应用。     

Thermal Buckling of Multi-Walled Carbon Nanotubes Based on a Rigorous van der Waals Interaction

This paper reports the result of an investigation on the axially compressed buckling of multi-walled carbon nanotubes under thermal load, based on a rigorous van der Waals interaction which is dependent on the change of interlayer spacing and the radii of tubes. From the point of view of continuum modeling, each of the concentric tubes of multi-walled carbon nanotubes is considered as an individual elastic shell and coupled with any two tubes through a rigorous van der Waals interaction force. Based on this model, some example calculations are carried out to describe the effect of temperature changes and van der Waals interaction models on the axially critical load of multi-walled carbon nanotubes. Some results obtained show that the axial buckling stress of multi-walled carbon nanotubes under thermal environment is dependent on the wave number of axially buckling modes, and the wave numbers corresponding to the minimum axial stress are not unique for the multi-walled carbon nanotubes under thermal environments. On the other hand, a rigorous van der Waals interaction force can make the axially critical load of multi-walled nanotubes under thermal loading increase. The effect of thermal environments on the axially critical stress of multi-walled nanotubes gradually increases as the axial half wavenumber (m) of buckling modes increases.