Analysis of the 3D distribution of stacked self-assembled quantum dots by electron tomography

The 3D distribution of self-assembled stacked quantum dots (QDs) is a key parameter to obtain the highest performance in a variety of optoelectronic devices. In this work, we have measured this distribution in 3D using a combined procedure of needle-shaped specimen preparation and electron tomography. We show that conventional 2D measurements of the distribution of QDs are not reliable, and only 3D analysis allows an accurate correlation between the growth design and the structural characteristics.     

用于市政和工业冷却塔剩余水的有机多功能组成物

本发明提供了一种名叫IMP-TE-516的水溶性组成物,其提高了市政和工业冷却塔剩余水化学处理的效果,具有低含盐量如膦酸盐和碳酸钙的特征,用于精炼厂的冷却塔储存水中,在高浓缩倍数下工作,准确地控制热交换设备中的腐蚀、结垢,同时还比较了处理设备的污染趋势,特别是在催化设备、主要级设备和粘性还原设备中。其还可以有助于减少由于这些冷却水系统的清洗引起的金属污染问题,这些化学组成物是全有机且可以被生物降解。本文提供的技术可以作为一种非常先进的水处理技术,原因是这种产品组成的特征。为了优化组成物剂量,可以通过使用伏特计确定冷却水系统循环水情况。     

UV-photopolymerisation of poly(methyl methacrylate)-based inorganic-organic hybrid coatings and bulk samples reinforced with methacrylate-modified zirconium oxocluster

In this work, we developed and optimised a synthetic route which enables to produce by spray-coating hard, transparent and stable inorganic-organic hybrid coatings for a wide variety of different substrates (e.g. stone, stainless steel, polymethylmethacrylate, polyethylene, wood, anodized aluminum). Chemically and thermally stable acrylate-based hybrid materials embedding the zirconium oxocluster Zr₄O₂(OMc)₁₂, OMc(CH₂C(CH₃)C(O)O) were prepared and UV-cured.The coatings of different compositions on different substrates were characterized by numerous analytical and spectroscopic methods such as FT-IR spectroscopy, Angle Resolved-XPS (AR-XPS), Secondary Ion Mass Spectrometry (SIMS), X-ray Absorption Spectroscopy (XAS), Environmental Scanning Electron Microscopy (ESEM) and Energy Dispersive X-ray analysis (EDX). Bulk samples were also prepared for additional characterizations. The bulk samples were analysed by FT-IR, whereas the cross-linking degree was qualitatively evaluated by swelling experiments. As far as the mechanical properties are concerned, the shear storage modulus (G′) and loss modulus (G″) were measured by Dynamical Mechanical Thermal Analysis (DMTA) technique. Moreover, the best conditions for the curing and cross-linking processes of the hybrid materials were studied up to 200 °C by using Differential Scanning Calorimetry (DSC). The thermal stability of the hybrid samples was evaluated by Thermogravimetric Analysis (TGA).     

A Method for Identification of Bearing Force Coefficients and Its Application to a Squeeze Film Damper with a Bubbly Lubricant

A general formulation of the instrumental variable filter (IVF) method for parameter identification of a n-DOF (Degrees Of Freedom) mechanical linear system is presented. The IVF is a frequency domain method and an iterative variation of the least-squares approximation to the system flexibilities. Weight functions constructed with the estimated flexibilities are introduced to reduce the effect of noise in the measurements, thus improving the estimation of dynamic force coefficients. The IVF method is applied in conjunction to impact force excitations to estimate the mass, stiffness, and damping coefficients of a test rotor supported on a squeeze film damper (SFD) operating with a bubbly lubricant. The amount of air in the lubricant is varied from nil to 100 percent to simulate increasing degrees of severity of air entrainment into the damper film lands. The experimental results and parameter estimation technique show that the SFD damping force coefficients increase as the air volume fraction in the mixture increases to about 50 percent in volume content. The damping coefficients decrease rapidly for mixtures with larger air concentrations. The unexpected increase in direct damping coefficients indicates the complexity of the SFD bubbly flow field and warrants further experimental verification.