关键词： 动力机械   合肥市   经济技术开发区   装备制造企业   船用柴油机   安徽省  

摘要： 合肥熔安动力机械有限公司是以船用柴油机为主要产品的大型装备制造企业，公司2007年8月在合肥注册成立，厂区位于安徽省合肥市经济技术开发区派河以东、宿松路以西区域。

关键词： 技术协会   化工机械   成都   会员   中国   副理事长   常务理事   理事会  

摘要： 中国化工机械动力技术协会第六次会员大会于2010年9月3日至4日在四川成都召开。出席本次大会的代表共103人。大会投票选举产生了第六届理事会,由理事144名组成。在第六届理事会第一次会议上,经投票选举常务理事43名,选举孙腾良同志为理事长,王峰涛、李光、李建平、李韵、李英翔、杨辉章、罗庆洪、胡迁林、黄进（按姓氏笔画为序）9同志为副理事长,选举程治方同志为秘书长。

关键词： 动力机械   总裁   合肥   传奇   东方   船舶工业   装备制造业   船用设备  

摘要： 没有自己的发动机，船舶工业就没有未来。 在国内装备制造业中，一直流传选择一句话：“只要有心，就有希望”。目前我国船用设备本土化配套率不是50%，作为船舶的心脏，一直制约着我国船舶工业的发展。

关键词： Multiscale   Molecular Dynamics   Lattice   Nanomolding   Nanotribology  

摘要： A coarse particle method for coupling continuum and molecular models is described. In this method, the continuum model was assumed to be in a lattice form and the interaction parameters were provided. Coarse particles can be applied in non-characteristic areas or in regions far away from large deformations, thus highly improving the efficiency. Defining a critical strain for different lattice sizes makes lattice refinement easier. In the thermal equilibrium case, the efficiency exceeded 100 times that of a classical molecular dynamics (MD) simulation with great numerical precision. To test the connection at the molecular/continuum interface, a large deformation case was studied in the nanomolding process. Only a slight deviation was found when the results were compared with the MD simulation. The effects of mold size, filling density, and contact angle decreased slightly when the mold width was increased.

关键词： Micro-mechanics   Mechanical properties   C-S-H  

摘要： Cement paste is the matrix material for concrete and cement based composites. This paper presents a molecular dynamics (MD) method for estimating mechanical properties of hydrated cement major constituents: calcium-silicate-hydrate (C-S-H) structurally related tobermorite 14 angstrom and jennite, and calcium hydroxide (CH). Microporomechanics technique is used to calculate properties of two types of C-S-H, namely, low density (LD) and high density (HD) C-S-H gels. Simulation results reported by the authors were compared with existing computational and experimental values. This research is intended to give a general step to study the complicated cement hydrated products from a multiscale view. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Electrochemical discharge phenomenon   Hysteresis   Bistability   Anode/cathode effect   Gas film life-time  

摘要： A model for the prediction of the current-voltage characteristics of a two electrodes cell incorporating the dynamics of the gas film formed during the electrochemical discharge phenomenon is developed. In its mean-field version, the model presents good qualitative agreement but overestimates the hysteresis effect and predicts too large current densities for the cell operation once the gas film is formed. An improved stochastic model, which assumes gas film departures from the electrode surface according to a Poisson process, addresses these issues and gives significantly better predictions. Two relations are presented which allow estimating the mean gas film detachment time and its variance from the experimental study of the hysteresis in the forward and reverse scan of a two electrode cell operated at high current densities.

关键词： Kinetics   Treatment plants   kinetic model   Volatile Solids   Reaction rates   model parameters   Environmental conditions   composting   optimum moisture content   Refuse composting  

摘要： This study focuses on the investigation of the kinetics of municipal solid waste composting in three full-scale mechanical-biological treatment (MBT) plants. The aims were to test a kinetic model based on volatile solids (VS) content change for describing the composting process in MBT plants, and to identify the model parameters that affected the estimation of the reaction rate constant most. To achieve this, VS content and several environmental conditions, namely temperature, moisture content, oxygen concentration and total bulk density were monitored throughout the composting process. Experimental data was fitted with a first-order kinetic model, and a rate constant (k) characteristic of composting under optimum environmental conditions was obtained. The kinetic model satisfactorily described the experimental data for the three MBT plants. k values ranged from 0.043 +/- 0.002 d(-1) to 0.082 +/- 0.011 d(-1). Sensitivity analysis showed that the model parameters that most affected the estimation of k were the initial biodegradable volatile solids content, the maximum temperature for biodegradation and the optimum moisture content. In conclusion, we show for the first time that full-scale MBT plants can be successfully modelled with a composting kinetic model. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Biomechanics   Biophysics/methods   Kinetics   Models, Molecular   Molecular Dynamics Simulation   Muscle Proteins/chemistry   Protein Kinases/chemistry   Protein Structure, Tertiary   Protein Unfolding   Ubiquitin/chemistry  

摘要： One of the applications of Molecular Dynamics (MD) simulations is to explore the energetic barriers to mechanical unfolding of proteins such as occurs in response to the mechanical pulling of single molecules in Atomic Force Microscopy (AFM) experiments. Although Steered Molecular Dynamics simulations have provided microscopic details of the unfolding process during the pulling, the simulated forces required for unfolding are typically far in excess of the measured values. To rectify this, we have developed the Pulsed Unconstrained Fluctuating Forces (PUFF) method, which induces constant-momentum motions by applying forces directly to the instantaneous velocity of selected atoms in a protein system. The driving forces are applied in pulses, which allows the system to relax between pulses, resulting in more accurate unfolding force estimations than in previous methods. In the cases of titin, ubiquitin and e2lip3, the PUFF trajectories produce force fluctuations that agree quantitatively with AFM experiments. Another useful property of PUFF is that simulations get trapped if the target momentum is too low, simplifying the discovery and analysis of unfolding intermediates.

关键词： chemical exchanges   diffusion   integral equations   molecular dynamics method   reaction kinetics   solvation   statistical mechanics  

摘要： Extraction of relaxation times, lifetimes, and rates associated with the transport of topological charge defects in hydrogen-bonded networks from molecular dynamics simulations is a challenge because proton transfer reactions continually change the identity of the defect core. In this paper, we present a statistical mechanical theory that allows these quantities to be computed in an unbiased manner. The theory employs a set of suitably defined indicator or population functions for locating a defect structure and their associated correlation functions. These functions are then used to develop a chemical master equation framework from which the rates and lifetimes can be determined. Furthermore, we develop an integral equation formalism for connecting various types of population correlation functions and derive an iterative solution to the equation, which is given a graphical interpretation. The chemical master equation framework is applied to the problems of both hydronium and hydroxide transport in bulk water. For each case it is shown that the theory establishes direct links between the defect's dominant solvation structures, the kinetics of charge transfer, and the mechanism of structural diffusion. A detailed analysis is presented for aqueous hydroxide, examining both reorientational time scales and relaxation of the rotational anisotropy, which is correlated with recent experimental results for these quantities. Finally, for OH(-)(aq) it is demonstrated that the "dynamical hypercoordination mechanism" is consistent with available experimental data while other mechanistic proposals are shown to fail. As a means of going beyond the linear rate theory valid from short up to intermediate time scales, a fractional kinetic model is introduced in the Appendix in order to describe the nonexponential long-time behavior of time-correlation functions. Within the mathematical framework of fractional calculus the power law decay similar to t(-sigma), where sigma is a paramet

关键词： SOLVATION   MOLECULAR dynamics   LIQUIDS   GEODESICS (Mathematics)   POTENTIAL energy surfaces   RELAXATION phenomena   CHEMICAL reactions  

摘要： It is not obvious that many-body phenomena as collective as solute energy relaxation in liquid solution should ever have identifiable molecular mechanisms, at least not in the sense of the well-defined sequence of molecular events one often attributes to chemical reactions. What can define such mechanisms, though, are the most efficient relaxation paths that solutions take through their potential energy landscapes. When liquid dynamics is dominated by slow diffusive processes, there are mathematically precise and computationally accessible routes to searching for such paths. We apply this observation to the dynamics of preferential solvation, the relaxation around a newly excited solute by a solvent composed of different components with different solvating abilities. The slow solvation seen experimentally in these mixtures stems from the dual needs to compress the solvent and to do solvent-solvent exchanges near the solute. By studying the geodesic (most efficient) paths for this combined process in a simple atomic liquid mixture, we show that the mechanism for preferential solvation features a reasonably sharp onset for slow diffusion, and that this diffusion involves a sequential, rather than concerted, series of solvent exchanges. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3481655]