Lanxide^TM法制备SICp／Al复合材料

Ｌａｎｘｉｄｅ＾ＴＭ技术是制备铝基复合材料的一种新方法,适于制备低孔隙率的ＭＭＣ。本文对利用该技术制备ＳｉＣｐ／Ａｌ复合材料进行了综述,阐述了Ａｌ对ＳＩｃＰ的润湿、渗透及界面反应等问题,并介绍了增强ＳｉＣｐ／Ａｌ的润湿、渗透及控制界面反应的方法。     

超临界流体萃取植物中液态组分溶解度的研究

分析了超临界流体（ＳＣＦ）萃取植物中液态组分过程的特点；推导出计算植物中液态组分在ＳＣＦ中溶解的渗透－缔合模型，并就文献发表的实验数据对模型的适用性进行验算，获得较满意的结果。     

分批精馏模拟技术

综述了当前分批精馏模拟技术的研究进展。介绍了作为目前快捷（ｓｈｏｒｔｃｕｔ） 模型主流的ＦＵＧ快捷模型和ＩＳＣ 快捷模型。与严格模型相比,ＦＵＧ模型和ＩＳＣ 模型具有适应性强、计算量小、计算精度较高的独特优点。     

DCS在千吨青霉素结晶生产过程中的应用

介绍千吨青霉素结晶生产过程采用Ａｃｔｉｏｎ公司ＣＩＭ－ＰＡＣ２２００ＤＣＳ系统的硬件组成和软件结构及实际投运效果。     

首届Uniqema中国区配方竞赛揭晓

Ｕｎｉｑｅｍａ公司成立于１９９９年１月 ,是由原ＩＣＩ集团下属的ＩＣＩＳｕｒｆａｃｔａｎｔｓ、ＩＣＩＳｙｎｔｈｅｔｉｃｌｕｂｒｉｃａｎｔ、Ｍｏｎａ、Ｓｏｌａｖｅｉｌ及Ｕｎｉｃｈｅｍａ５家子公司合并而成。新的Ｕｎｉｑｅｍａ公司是ＩＣＩ集团下属的一家子公司 ,在个人护理、润滑油、聚合物等领域开展业务。同时ＩＣＩ集团中还有ＮａｔｉｏｎａｌＳｔａｎｃｈ、Ｑｕｅｒｔ及Ｃｒｏｓｓ ｆｉｅｌｄ３家子公司在个人护理品领域开展业务。每家子公司都具有明显特色的产品范围。Ｕｎｉｑｅｍａ公司于１９９９年在中国举办首次化妆品…     

应用ObjectARX开发给水管网GIS系统

在对ＡｕｔｏＣＡＤ２０００、ＯｂｊｅｃｔＡＲＸ,给水管网计算机管理系统和ＧＩＳ分析的 ,提出给水管网计算机管理系统开发的一般过程和用ＯｂｊｅｃｔＡＲＸ和扩展字典功能进行管网系统ＧＩＳ开发的方法,并通过编写ＷＤＯＣ软件系统得到验证。     

R－407是HCFC－22的有效替代物

Ｒ－４０７是ＨＣＦＣ－２２的有效替代物ＩＣＩＡｍｅｒｉｃａｓｌｎｃ公布了最近加拿大国家研究委员会进行的试验结果，指出了ＩＣＩ公司的Ｋｌｅａ４０７Ａ是能效最好的ＨＦＣＳ替代物。在ＨＦＣＳ替代物的测试中，Ｋｌｅａ４０７Ａ在所有试验条件中能效比Ｒ－５０２约...     

近几年开发的国外农药新品种（5）

甲氧磺草胺（ｍｅｔｏｓｕｌａｍ）ＮＨＳＯ２ＮＮＮＮＯＣＨ３ＯＣＨ３ＣｌＣｌＣＨ３Ｃ１４Ｈ１３Ｃｌ２Ｎ５Ｏ４Ｓ４１８３中文通用名称甲氧磺草胺英文通用名称ｍｅｔｏｓｕｌａｍ（ＢＳＩ,ＩＳＯ,ＡＮＳＩ）商品名称Ｅｃｌｉｐｓｅ;Ｐｒｏｎｔｏ;Ｓａｎｓａｃ;...     

加压和超临界流体在多孔膜中的渗透

考察加压和超临界流体在多孔膜中渗透过程的各种影响因素并进行模型分析,对深入认识过程的传质机理、开发普遍适用的数学模型有重要意义。首先实验测定了不同温度、压力和压差条件下,He、N2和CO2在多孔陶瓷膜中的渗透率,考察了各主要影响因素。以二项尘气模型为基础,考虑到流体枯度随压力的变化,特别是近临界区流体枯度可能出现的突变,对模型进行了修正,建立了新的模型表达式。理论分析与实验结果表明,加压和超临界条件下,由于He的粘度变化甚微,其渗透过程仍然符合二项尘气模型,而对于N2需要考虑粘度随压力变化对渗透率计算结果的影响。由于近临界区相交的作用,CO2在多孔膜中的渗透过程出现奇异现象;而在低压和高压条件下,本研究建立的渗透模型与实验结果十分吻合。     

Shell加压粉煤气流床气化技术的开发和应用

介绍了荷兰Ｓｈｅｌｌ加压粉煤气流床气化技术的开发过程及位于荷兰南部林堡省的Ｄｅｍｋｏｌｅｃ采用Ｓｈｅｌｌ气化工艺建成的目前世界上最大的ＩＧＣＣ示范厂的工艺流程、运行状况和下一步发展展望。     

L—抗坏血酸结晶成核的研究

介绍了L－抗坏血酸在水和水－低碳醇混合溶剂中结晶成核的测定方法，同时还研究了甲醇，乙醇，异丙醇对其成核的影响。应用Kubota提出的成核模型，对加晶种操作过程进行了详细考察，按照不同的降温速率，测得溶液的极限过冷度，从而确定了有关动力学参数。讨论了温度对常数kb和指数n的影响。     

The role of solute conformation,solvent–solute and solute–solute interactions in crystal nucleation

The induction time for nucleation can differ based on the solutions used to conduct a crystallization, which can in turn impact the efficiency and economics of a crystallization process, the crystal size distribution, the morphology and ultimately functionality of the final product. Establishing a link between the nucleation pathway/solution structure and nucleation induction time is essential to achieve improved comprehension of the process of crystal nucleation from solution. In this study, the role of solute conformation, solvent–solute interaction, and solute–solute interaction in nucleation was examined using tolbutamide as a model compound in toluene and toluene–alcohol solutions. Through a combination of induction time experiments, attenuated total reflection Fourier transformed infrared spectroscopy, nuclear magnetic resonance spectroscopy, molecular dynamics simulations, and quantum chemical calculations, it was found that not only solvent–solute interactions but also solute–solute interactions and structural similarities between molecular self-assemblies in the solution and synthons in the crystal structure, can significantly influence the nucleation induction time.     

A basic population balance model for fluid bed spray granulation

A basic population balance approach is developed for a granulation process in a fluid bed spray granulator. The particle size distribution predicted by the model is confirmed by plant data. Hence this model is considered to be useful to describe and optimize an industrial process. The model depends on a limited number of parameters (most of these factors can be measured or are known): the spray volume flux, the nucleation fraction (the fraction of the spray volume flux which leads to new particles formed), the nucleation particle diameter, the product withdrawal threshold diameter, and the product withdrawal rate. Analysis of the model reveals a steady-state constraint; a steady state does not exist if the nucleation fraction is too large. For cases where the steady state does exist, the steady-state particle size distribution is solved analytically. A numerical implementation of the model is used to illustrate the transient evolution of the process. The steady-state solution appears to be stable for a constant nucleation fraction. However, if the nucleation fraction depends on the bed height the steady state can be unstable. Such a situation may occur if the spray inlet is near the height of the bed surface. Instead of convergence towards a steady state, the transient solution displays ongoing oscillatory behavior with an oscillation period of a number of hours. A linear stability analysis is performed to confirm the findings on the stability of the steady state.     

Seeded Induction Period and Secondary Nucleation of Lithium Carbonate

Seeded nucleation of lithium carbonate in aqueous solution during reactive crystallization was monitored by FBRM (focused beam reflectance measurement) and PVM (particle video microscope). The impacts of operating variables, such as seed size and loading, stirring speed, on induction period and secondary nucleation were investigated and explained by an adsorption model. The results show that seed surface area plays an important role in secondary nucleation, for more surface area has higher adsorption capacity and consumes more supersaturation on seed growth, thus restrains nucleation better. A method through comparison between pure breakage/attrition and nucleation process was put forward to distinguish attrition-induced and surface-induced nucleations quantitatively, which can reveal the contributions of different nucleation mechanisms. The nucleation processes in different conditions were studied, the principles and valuable experimental data were obtained for seeding approach primarily. FBRM and PVM are useful on-line apparatuses to facilitate seed selection and seeding optimization.     

The role of diffusion in the nucleation of calcium carbonate

Nucleation widely exists in nature, from cloud formation to haze generation. The classical nucleation theory (CNT) was created to describe the nucleation process, but it fails to predict many experimental phenomena due to the short consideration of nanoscale phenomena and macroscale dynamics. Although the attachment and detachment of monomers are considered in the developed model of nucleation, the diffusion of chemicals in the bulk is not valued as supersaturation in the nucleation process so far. Here we employ simulation and experimental approaches to investigate how the diffusion of ions affects the nucleation of calcium carbonate. The diffusion of ions is regulated by the viscosity of solvents and the sonication imposed on the solution. It is found that the nucleation rates increased exponentially with the diffusion coefficient of ions, which is beyond the prediction of CNT. This abnormal finding might be ascribed to the involvement of cluster aggregation in the nucleation of calcium carbonate. This study highlights the significance of chemical diffusion in the nucleation process, which may help to revise the nucleation theory and develop solutions for the rational synthesis of materials, as well as for the control of air pollution.     

五水柠檬酸钠连续结晶动力学研究

研究了五水柠檬酸钠的连续结晶过程。利用马尔文激光粒度分析仪对不同温度和停留时间下连续结晶过程产品的粒度分布进行分析。通过实验数据和粒度无关生长模型,分别计算了连续结晶过程中五水柠檬酸钠晶体生长与成核速率方程。研究表明,在33.3℃的连续结晶过程中,五水柠檬酸钠的成核速率较生长速率对溶液的过饱和度变化更敏感,增加溶液过饱和度更易形成较小粒度的晶体。     

Comparative Study of the Influence of Homogeneous and Heterogeneous (Multi‐Phase) Precipitation Processes on the Particle Size Distribution

A Plexiglas vessel of a 0.30 m diameter filled with a diluted barium chloride solution and mixed by bubbling of an inert gas is used to model an industrial process. Solid sodium sulfate or sodium sulfate solution are added into the reactor to provoke the precipitation of barium sulfate. Two precipitation models, homogeneous and heterogeneous, are proposed. Especially, the heterogeneous precipitation model (much more complex than the homogeneous one) takes into account all elementary phenomena such as the dissolution of the solid phase, the nucleation in the liquid‐solid boundary layer and the nucleation and crystal growth in the bulk of liquid phase. Both models well predict the precipitate mean particle sizes. The decrease of the particle size in the case of the heterogeneous process is due to higher nucleation rate compared to the homogeneous process because of higher values of the sodium sulfate concentration in the boundary layer than those existing in the bulk.     

Effect of reaction conditions on size and morphology of SiO2 powder in a sol-gel process

We have investigated effects of the reaction conditions such as mixing of solution, reactant concentration, feeding time and molecular weight of alcohol solvents on the size and morphology of silicon oxide in a sol-gel process in Rushton type reactor. To describe the intensity of mixing of solution the power input, which means the energy dissipated in the solution, was used. The particle nucleation and growth processes of silicon oxide were varied with all the reaction conditions. However, the particle morphology of silicon oxide depended mostly on the reactant concentration and molecular weight of alcohol solvents under various reaction conditions. If the supersaturation level of silicon oxide in the solution was promoted by variation of reaction conditions, the particle nucleation and growth processes were facilitaled and it resulted in reduction of relative induction time and in increase of mean particle size of silicon oxide. To explain the principal mechanism of particle growth process of silicon oxide the two-step growth model was applied.     

超临界CO2脱附作用调控负载纳米颗粒结晶动力学研究

依据经典成核理论和超临界领域中的结晶动力学相关模型,分析影响成核速率的主要因素及其规律。研究共溶剂辅助超临界CO₂溶解无机盐,在SBA-15介孔材料表面沉积实验的结果,发现伴随初始阶段的泄压速率逐步提升（0.05~18 MPa/min,20~14 MPa）,载体所负载的纳米颗粒的粒径逐渐减小至1.5 nm左右,与典型的晶核尺寸1 nm相接近,而担载量却出现逐渐增加的趋势。晶体的临界成核半径取为0.5 nm,通过Türk模型和Debenedetti模型计算超临界流体快速膨胀（RESS）工艺其喷嘴内的成核速率,与超临界反溶剂（SAS）群体平衡模型（PBM）的边界条件即SAS过程的初始成核速率相比较,三者的成核速率相接近,且利用快速泄压方法的沉积实验结果与按Cu担载量所估算的成核速率相接近。分析在沉积反应后的泄压阶段,超临界条件下的CO₂的脱附作用,可能成为吸附于载体表面的前驱物离子结晶的诱导因素。并且CO₂瞬时脱附量能够调控负载型纳米颗粒的成核速率,同时控制复合材料的金属担载量。为研究微观尺度下SAS过程的实现提供了实验与理论基础。     

工业结晶过程中结晶动力学模型探讨

针对工业结晶过程中的溶液结晶部分,探讨了晶体成核和成长的动力学模型,并对模型的应用情况进行了简单的阐述。