摘要： Computer simulations are an indispensable tool in microfluidics because of the lack of analytical solutions. We have developed a simulation tool in Matlab based on the finite element method (FEM). At the present stage, the tool can be employed to handle general second order partial differential equations in two dimensions. The tool has been applied to model incompressible laminar flow, and it has been tested on the classical problem of flow over a backward-facing step. Also the tool has been employed to model non-Newtonian blood flow in a microchannel, in relation to an experiment performed by Lennart Bitsch, using micro particle-image velocimetry (μPIV) measurements to map out the velocity profile of blood flowing in a thin glass capillary. The joint work has resulted in two conference proceedings [1, 2] and a paper submitted to Experiments in Fluids [3]. Finally we have considered the problem of electroosmotic flow in a pore system on the submicron scale where the Debye layer overlap is non-neglible. At the time of writing the results are still preliminary, yet they demonstrate that our FEM tool is general enough to accomodate for more complex prob- lems occuring in the field of microfluidics.

关键词： 微机电系统   微流体分析系统   MEMS   发展  

摘要： 微机电系统 (MEMS)是在微电子及微机械等学科基础上发展起来的新兴多学科交叉研究领域 ,是当今科学技术最具潜力的发展方向之一 ,而微型流体分析系统是这一研究领域中的热点。本文综述了MEMS技术以及作为MEMS技术一个重要研究方向的微型流体分析系统的起源及其广阔的市场应用前景 ,并对MEMS产品的市场化存在的问题进行了讨论。MEMS技术及微型流体分析系统的诞生必将对今后的化学、医学及生物学等领域的研究工作产生重大影响。

关键词： 微泵   致动器   微机械电子系统   微流体系统   驱动方式  

摘要： 介绍了国内外微流体系统中微泵的致动原理和结构 ,分析了各种致动方法的优缺点 ,对微泵的发展方向做出了展望。

关键词： 西天山   伊耳曼得型金矿   流体   成矿   火山岩  

摘要： 西天山一种以伊耳曼得和恰布坎卓它等金矿为代表的金矿类型,其成矿流体液相成分以K+离子为主,其次是Na+、Cl-、SO42-及少量的Ca2+、Mg2+.流体气相成分以H2O为主,其次是CO2、H2,少量的O2、N2、CH4和CO.流体的矿化度平均为8.28g/L,盐度比较低,其范围为1.5%～0.39%(NaCl),流体的pH值在2.8～5.5之间.流体离子强度为0.146～0.18.氧逸度为lgf o2=-35.2～-38.9,流体的pH-lgf o2稳定范围与冰长石-绢云母型和酸性硫酸盐型金矿床的稳定范围不一致.流体温度范围为93～151.4℃.流体压力范围为5.6～17MPa.表明成矿流体具有低温、低压和低盐度的特点.流体属于H2O-NaCl-CO2体系,来自大气降水.大气降水渗滤到地下,受到火山和地温梯度的影响,形成了沿一定深度运动的热循环流体.成矿流体的物理化学环境是一种过渡类型.成矿流体沿火山碎屑岩孔隙和微裂隙多次渗透交代而成矿.

关键词： 环境友好   超临界流体技术   化工生产   环保领域   应用  

摘要： 介绍了近几年来超临界流体技术在超微粒子的制备、复相催化反应以及环境保护中的应用。

关键词： 协同电子商务   物流体系   信息系统   供应链   虚拟物流   第四方物流  

关键词： 超临界流体   环境保护   萃取技术  

摘要： 超临界流体萃取技术是近年来国际上取得迅速发展的新兴分离技术 ,对治理环境应用前景广泛。文章对超临界流体萃取在环境分析中的应用作了阐述。

关键词： 二尖瓣狭窄   心房纤颤   窦性心律   左房流体力学  

摘要： 在我国风湿性心瓣膜病患者中，二尖瓣病变发病率最高。需外科手术的二尖瓣病变患者约80％伴有心房纤颤(atrial fibrillation，AF)。即使手术成功，术后大多数患者的 AF仍持续存在。但至今二尖瓣病变所伴随AF的发病机制仍不清楚。同样是中-重度二尖瓣狭窄(MS)，虽多数患者伴 AF，却有少数患者仍为窦性心律(sinus rhythm，SR)。这种差异是否与左房流体力学环境、特别是左房机械应力(简称应力)有关尚不清楚，为此我们进行了研究。

关键词： CFD技术   建筑环境   设计  

摘要： CFD(计算流体动力学)技术的发展非常迅速,已渗透到航空航天、能源、石化等多个领域,本文针对建筑领域,从建筑物小区规划、内部通风设计、建筑设备设计及室内热环境分析等方面出发,简述CFD技术对建筑环境设计方面的作用。

关键词： .orientations   low temperatures   exchange rate   lowest excited   Jahn-Teller   ZFS   Subphthalocyanine   fluid solution   Solid and Fluid   Lowest Photoexcited Triplet   Time-resolved EPR  

摘要： Time-resolved EPR spectra of the lowest excited triplet state of boron subphthalocyanine chloride have been measured in toluene at various temperatures (5-360 K). On the basis of the observed and simulated spectra, electronic structure and molecular motion of the triplet state (T-1) were analyzed, both in solid and fluid solution. The simulations were carried out using a model, which considers a temperature-dependent exchange between sites having different zero-field splitting (ZFS) parameters and molecular orientations. The ZFS parameter, D, was nearly the same at all temperatures examined. At very low temperatures, below 20 K, the spectrum was analyzed by a static model. At 40-120 K, two conformers with different ZFS parameter, E, have been found. The population ratio between the two conformers showed strong temperature dependence. These conformers were attributed to Jahn-Teller states and were identified by their different ZFS parameters. The exchange rate and activation energy of the conformers were compared with similar experiments performed in solid solution. Further increase in temperature (130-160 K) resulted in noticeable change in the spectra. However, at this temperature range the spectra could not be analyzed quantitatively because of the unstable crystal structure of toluene (soft glass). Above 163 K, the solvent turns slowly into fluid and the spectra were strongly dependent upon temperature. In this range of temperatures, molecular rotations occur, initially around the out-of-plane z-axis, and, as temperature rises, also around the in-plane x- and y-axes. Anisotropic exchange rates were obtained from the spectral simulation and were analyzed by a population exchange between the Jahn-Teller states combined with anisotropic rotations. Anisotropic spin-lattice (T-1) and spin-spin (T-2) relaxation times were also obtained and discussed. The rotations become isotropic above 263 K, where the spectrum exhibits a single sharp Lorentzian line and is analyzed i