Study of the effect of process parameters for n-heptylamine plasma polymerization on final layer properties

Plasma polymerization processes are widely used to chemically functionalize surfaces, which properties can be tuned by different operating variables. In this study, thin amine-containing polymer layers were produced on solid substrates in a custom-made cylindrical plasma polymerization reactor by radio frequency glow discharges of n-heptylamine vapours. Carefully planned experiments were conducted to evaluate the importance of four different process parameters on the chemical composition and thickness of the resulting films. The parameters investigated were: 1) deposition time, 2) power of the glow discharge, 3) distance between the electrodes, and 4) monomer pressure. Possible interactions between these variables were investigated through the use of statistical analyses (i.e., factorial design). This study reveals that n-heptylamine plasma polymer (HApp) layer thickness is influenced by the power of the glow discharge and the deposition time, as assessed by surface plasmon resonance and atomic force microscopy step height measurements. Also, the atomic ratio of nitrogen to carbon atoms on the treated surfaces is mainly influenced by the power of the glow discharge, as revealed by X-ray photoelectron spectroscopy. Quartz crystal microbalance analysis also confirmed that HApp layers are stable when immersed in aqueous solution.     

Crystallization of β-FeSi2 droplets on silicon substrates by room-temperature pulsed laser deposition

This paper reports the fabrication process of β-FeSi₂ droplets on silicon substrates at room temperature by ArF excimer pulsed laser deposition (PLD). The chemical treatment of substrate could compensate the thermal treatment of the deposited droplets. Observations with the transmission electron microscopy revealed that the crystallization of droplet began from the surface of droplet rather than from the interface between the melt and the substrate.     

Effects of deposition parameters on SiCln (n=0-2) densities in SiCl4 glow discharge plasma

The relative densities of SiCl_n (n=0-2) in SiCl₄ radio frequency (rf) glow discharge plasma are measured by mass spectrometry. The effects of discharge parameters, including rf power, discharge pressure, substrate temperature and SiCl₄ flow rate on the relative densities of SiCl_n (n=0-2) are investigated in detail. The experimental results demonstrate that the relative densities of SiCl_n (n=0-2) in SiCl₄ plasma are dependent strongly on these discharge parameters. An optimum configuration of discharge parameters (low rf power, high discharge pressure, low substrate temperature and low flow rate), which enhanced the formation of SiCl_n (n=0-2) radicals, was searched. Further, researching of SiCl_n (n=0-2) spatial distribution for seeking a suitable deposition condition is beneficial for understanding the deposition mechanism of thin films.     

Thermodynamic and experimental study of chemical bath deposition of Zn(S,O,OH) buffer layers in basic aqueous ammonia solutions. Cell results with electrodeposited CuIn(S,Se)2 absorbers

This paper presents a thermodynamic study of Chemical Bath Deposition (CBD) of zinc sulphide based films in aqueous ammonia solutions. The aim is a better understanding of ammonia and temperature effects on the deposition conditions and films composition. The formation of solid phases has been predicted by means of the precipitation conditions of ZnO, Zn(OH)₂ and ZnS as a function of temperature between 298 and 333 K. Films have been deposited according to calculated diagrams and preliminary results on solar cells based on electrodeposited CuIn(S,Se)₂ layers have been demonstrated. Composition and thickness of the films have been extracted to link the theoretical study with experiments.     

On Surface Finish and Dimensional Accuracy of FDM Parts after Cold Vapor Treatment

Fused deposition modeling (FDM) process is an additive manufacturing technology where objects are manufactured in layers. In the present days, FDM is commercially used to build prototypes, functional components; however, these parts majorly suffer from poor surface quality and dimensional accuracy even for basic part geometries. In the present paper, first the effect of part deposition orientation on surface finish and dimensional accuracy of FDM parts are studied. The part selected for this study is designed in such a way that different primitive geometric features at different directions are present. The parts are built at different orientations (0°, 15°, 30°, 45°, 60°, 75°, 90°) using acrylonitrile butadiene styrene P430 material, and surface finish and dimensional accuracy are measured at different surfaces. Next, the FDM parts are postprocessed by cold vapor treatment of dimethylketone (acetone) and improvement in surface finish and change in dimensional accuracy are investigated. The results show that surface finish of the components is greatly improved by this vapor treatment process with minimal variations in part geometric accuracy after the treatment.     

Optimization of the Quality Characteristics of Laser-Assisted Cold-Sprayed (LACS) Aluminum Coatings with Taguchi Design of Experiments (DOE)

This study employs Taguchi design of experiments to identify optimal process parameters (deposition temperature, transverse speed, powder feed rate, and operating pressure) associated with quality characteristics (porosity and hardness) of laser-assisted cold-sprayed (LACS) pure aluminum coatings. Optimal quality characteristics of the coatings were obtained by setting deposition temperature at 450°C, transverse speed at 5 mm/s, operating pressure at 30 bar, and powder feed rate at 25 rev/min. This study helps in improving the yield and stability of pure aluminum coatings produced via LACS process while it also reduces its variability which results in high rejection, rework, and warranty costs.     

CHARACTERISTICS OF RECTANGULAR MIXING VESSELS

Abstract

The convective diffusion equation of aerosols in the case of gas stream slip on the fibre cylindrical surface has been solved by means of the finite element collocation method. Half-analytical form of the solution makes it possible to examine directly changes the slip causes in the distribution of solids around the fibre surface. Concentration profiles and deposition efficiency computed by this method differ from the experiment results less than those obtained by the common method of finite differences. Additionally the finite element collocation has proved to converge more rapidly than that of finite differences (at optimal conditions of calculation for both methods).¹⁰     

黄酒厂的污水处理方法

文中介绍了有关黄酒污水处理的几种方法，基本特点，工艺流程。     

库车河阿艾阿仑——库台克力克侏罗系古气候及沉积环境分析

通过对库车河阿艾阿仑——库台克力克侏罗系地层特征的野外观察及沉积环境分析将阿艾阿伦——库台克力克侏罗系划分为下侏罗统阿合组、阳霞组,中侏罗统克孜勒努尔组、恰克马克组以及上侏罗统奇古组,喀拉扎组。该区经历了由亚热带、暖温带——亚热带半干旱、半潮湿——干旱炎热的亚热带型气候变化。根据沉积特征对沉积环境分析可推测阿合组主要为辫状河流沉积时期,阳霞组、克孜勒努尔组为主要的曲流河和辫状河发育期;恰克马克组为曲流河沉积时期;齐古组为湖泊发育期,而喀拉扎组由于变为干旱型气候而成为干旱气候条件下的湖泊沉积环境。