关键词： flocculation   synaeresis   kinetics   dewatering   moisture  

摘要： The authors analyze the kinetics of water removal from the orthokinetically formed floccules by mechanical synaeresis. The floccule moisture and time relationship is established under influence of unbalanced force system. It is found that the mechanical treatment of floccules in coal flotation concentrate at velocity gradient of 3-30 l/s reduces the product moisture by 1.5-2.0%, and the floccules integrity remains undisturbed. This finding allows reducing the concentrate drying cost by 10-15%.

关键词： Amorphous   Carbon nitride   Bonding configurations   Hardness  

摘要： Based on ab initio molecular dynamics method, four amorphous CNx, structures with different stoichiometries (CN0.47, CN0.67, CN0.92, and CN1.3) were generated within a 100-atom supercell. Characterizations of the pair correlation functions, bond length and the fraction of bond types of the amorphous carbon nitrides revealed that the N content in such structures plays a key role in determining the obtained structural networks. The calculations of the cohesive energy give direct evidence that experimentally synthesized amorphous carbon nitride films usually possess low nitrogen concentration. The competition relationship between sp(2) and sp(3) bonds was analyzed by electronic effect and electron density of states. The bonding states, especially the sp(3), affect greatly the hardness of these a-CNx compounds, implying a possible way to enhance the hardness of films via tuning the bonding states. (C) 2011 Elsevier B.V. All rights reserved.

关键词： MOLECULAR dynamics -- Simulation methods   POLYMERS   FINITE element method   DATA analysis   COMPUTER simulation   CONTINUUM mechanics   CONTACT mechanics  

摘要： This paper studies the rheology of weakly entangled polymer melts and films in the glassy domain and near the rubbery domain using two different methods: molecular dynamics (MD) and finite element (FE) simulations. In a first step, the uniaxial mechanical behavior of a bulk polymer sample is studied by means of particle-based MD simulations. The results are in good agreement with experimental data, and mechanical properties may be computed from the simulations. This uniaxial mechanical behavior is then implemented in FE simulations using an elasto-viscoelasto-viscoplastic constitutive law in a continuum mechanics (CM) approach. In a second step, the mechanical response of a polymer film during an indentation test is modeled with the MD method and with the FE simulations using the same constitutive law. Good agreement is found between the MD and CM results. This work provides evidence in favor of using MD simulations to investigate the local physics of contact mechanics, since the volume elements studied are representative and thus contain enough information about the microstructure of the polymer model, while surface phenomena (adhesion and surface tension) are naturally included in the MD approach.

关键词： 园林机械   汽油机   草坪修边机   术语   定义  

标准号: LY/T 2080-2012

摘要： 本标准规定了以汽油机为动力的手持式草坪修边机（以下简称为修边机）的术语和定义、技术要求、试验方法、检验规则、标志、使用说明书、包装、运输和贮存。 本标准适用于以汽油机为动力的手持式修边机。以其它内燃机为动力的修边机亦可参照使用。

关键词： Morphology   Crystallization   Crystal structure   Nanocomposites   Kinetics  

摘要： Biodegradable poly(epsilon-caprolactone) (PCL) and octavinyl-polyhedral oligomeric silsesquioxanes (ovi-POSS) nanocomposites were prepared at low ovi-POSS loadings via a solution casting method in this work. Scanning electron microscopy observation reveals not only the fine dispersion but also the crystallization of ovi-POSS in the PCL matrix. The overall isothermal melt crystallization kinetics, spherulitic morphology, crystal structure, and dynamic mechanical properties of neat PCL and its nanocomposites were studied with various techniques. The presence of ovi-POSS has enhanced the overall isothermal melt crystallization rates of PCL in the nanocomposites;however, the crystallization mechanism and crystal structure of PCL remain unchanged despite the ovi-POSS loading. In addition, the storage modulus of the nanocomposites has been enhanced significantly relative to neat PCL, while the glass transition temperature varies slightly irrespective of the presence of ovi-POSS.

标准号: JIS B9126-3-2012

标准号: JIS B9126-5-2012

标准号: JIS B9100-2012

标准号: JIS B9126-2-2012

标准号: JIS B9126-1-2012