镀液流速对碳化硅微粒与铜共沉积的影响

本文利用易于控制流速的旋转圆盘电极研究了SiC微粒与Cu的共沉积。得出了在不同镀液流动速度下镀得的复合镀层中微粒含量与镀液中微粒浓度以及与电流密度之间的关系曲线,进而探讨了镀液流速对Cu-SiC共沉积的影响。镀液流速通过影响微粒与阴极之间的弱吸附影响微粒在阴极表面的停留,从而对Cu-SiC复合电沉积过程产生很大影响。     

3-D hydrodynamics generated in a stirred vessel by a multiple-propeller system

The aim of this study is to optimize the position and the number of propellers in a non-standard tall vessel. Laser sheet flow visualization experiments were carried out for selected geometrical arrangements which produced stable flow patterns and good transport between the propellers. Four double-propeller arrangements corresponding to frequent industrial cases and a three-propeller system have been chosen. Comparison of LDA measurements in the r-z plane, dimensionless global parameters N_Qp, Nt_m, N_p, E_p and spatial distribution of local energy dissipation rate ? shows that a three-propeller system is the most efficient.     

Hydrodynamics of disturbed flow and erosion—corrosion. Part I — Single-phase flow study

Numerical simulations of turbulent flow have been used to determine the flow structure in a sudden pipe expansion, in order to explain the effects of disturbed flow on mass transfer controlled erosion–corrosion. Previously determined rates of mass transfer through the liquid boundary layer have been directly related to the predicted levels of near-wall turbulence. When rust films are present, the turbulent fluctuations affect both the mass transfer through the boundary layer and the removal of the film. The determining resistance to mass transfer, under the conditions examined, was that of the rust film.     

尿素生产中尿液的不稳定流动对尿素一分塔的影响

介绍了水溶液全循环法尿素生产系统中,一分塔的精馏段由泡罩塔盘改为规整填料后出现的一系列问题,针对尿液的不稳定流动造成一分塔规整填料严重腐蚀的原因,进行分析并提出整改和预防措施。     

MATHEMATICAL MODELING OF THROUGH-HOLE-PLATING IN ELECTROCHEMICAL MICROFABRICATION II. AXISYMMETRIC TWO-DIMENSIONAL CONVECTIVE MASS TRANSFER

Axisymmetrical, two dimensional mass transfer in a tube and a through-hole was studied. The elliptic convective-diffusion equation was solved numerically by taking into account both the axial and radial diffusion in the entrance region of an infinite tube. The whole mass-transfer region in a tube of finite length was also studied by dividing the domain into several regions according to different mass-transfer mechanisms. A similar analysis is then conducted for a through-hole geometry by assuming a modified Hagen-Poiseuille fluid pattern. Results show that mass-transfer rate in a through-hole is larger than that in a tube by approximately 10%. This is due primarily to faster fluid flow within the concentration boundary layer in a through-hole.     

塑料充模流动粘性模型研究

对多种塑料在不同温度下的剪切速率一稳态剪切粘度数据进行Cross粘性模型参数拟合，得到了表征材料粘度的模型参数(B，Tb，τ^*，n)。其拟合效果良好，能较准确地描述塑料熔体在一定剪切速率和温度范围内的粘流特性，为工程计算和塑料熔体模流分析提供了数据支持。结果表明，该方法有较广泛的适用性。     

容器设计中搅拌装置的轴向力分析

搅拌装置在化工厂中应用很广，在磷肥、钛白粉装置中（15kt/a)使用较多，仅钛白粉装置中就大约有40－50台，如增稠结晶器，中和槽等，搅拌操作所涉及的因素极为复杂，浆叶形式的选择，从力学的观点来说，迄今研究不够，本文就搅拌装置产生的轴向力问题进行了初步研究。     

A reactive extension of the OpenMusic visual programming language

Objectives: OpenMusic (OM) is a domain-specific visual programming language designed for computer-aided music composition. This language based on Common Lisp allows composers to develop functional processes generating or transforming musical data, and to execute them locally by demand-driven evaluations. As most historical computer-aided composition environments, OM relies on a transformational declarative paradigm, which is hard to conciliate with reactive data-flow (an evaluation scheme more adequate to the development of interactive systems). We propose to link these two evaluation paradigms in the same and consistent visual programming framework.Methods: We establish a denotational semantics of the visual language, which gives account for its demand-driven evaluation mechanism and the incremental construction of programs. We then extend this semantics to enable reactive computations in the functional graphs.Results: The resulting language merges data-driven executions with the existing demand-driven mechanism. A conservative implementation is proposed.Conclusions: We show that the incremental construction of programs and their data-driven and demand-driven evaluations can be smoothly integrated in the visual programming workflow. This integration allows for the propagation of changes in the programs, and the evaluation of graphically designed functional expressions as a response to external events, a first step in bridging the gap between computer-assisted composition environments and real-time musical systems.     

Modelling water flow,nitrogen transport and root uptake including physical non-equilibrium and optimization of the root water potential

A model is presented for the simulation of water flow, heat flow, and nitrate and ammonium transport. Two approaches are used for modelling plant water uptake as well as for plant nitrogen uptake. Nitrogen transformations are accounted for in a very simple way. This paper focuses mainly on water flow modelling, solute transport, and water uptake. Richards' equation is used to model water flow in layered soil profiles with a great variety of boundary conditions. Solute transport is simulated with either a simple convection dispersion equation or with a two-region physical non-equilibrium model to distinguish between mobile and immobile water and solute exchange between these two regions. A macroscopic sink term is added to Richards' equation to account for plant water uptake. This term can be calculated along two different approaches, one of which is based on the concept of root water potential. The root water potential is then continuously optimized to minimize the difference between the climatic demand and the uptake rate.Simulation results are compared with field data from the Netherlands to illustrate the degree to which the model is able to predict water flow, solute transport and plant water uptake. The root water potential optimization model seems to provide the best prediction of water distribution. In particular the shape of the profile, revealing uptake patterns, is quite well reproduced with this model. Comparison of simulated and observed water content profiles seems also to reveal the presence of preferential pathways. The comparisons show also how predicted solute distributions can be improved by using a two-region approach rather than a simple convection-dispersion model.     

采用数据流图的故障模型生成算法及其应用

为有效地解决系统级故障注入试验建模困难问题,提出语言级生成数据流图,并以此构造动态故障树的故障模型建立方法.通过对故障过程数据流分析,找出数据依赖关系并构造了故障模型生成算法.与其他方法比较,本算法具有动态性,提高了故障覆盖率,减少了系统开销,使故障注入试验更易实现.