共查询到19条相似文献,搜索用时 125 毫秒
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混合药膜包膜系统释放动力学研究 总被引:1,自引:0,他引:1
建立了混合药膜包膜系统释放动力学的简化模型,采有热平衡双重积法获得了模型的解析解。模型预测值与实验值的比较表明,二者吻合较好。 相似文献
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固态发酵生产裂褶菌多糖的动力学研究 总被引:2,自引:0,他引:2
对固态发酵生产裂褶菌多糖的动力学过程进行了研究,基于Logistic方程和Luedeking-Pirct方程建立了裂褶菌固态发酵生成裂褶菌多糖的菌体生长、多糖合成和底物消耗的动力学模型,并对模型参数进行了非线性回归。结果表明,裂褶菌多糖的产量与菌体生长速率和底物消耗量均有关系,最大比生长速率为0.7385 d-1。模型预测值和实验值有良好的拟合性,菌体生长、多糖合成、底物消耗3条曲线的相关指数(R值)分别为0.99256、0.99163和0.98835。表明此动力学模型可以较好地定量描述裂褶菌多糖的固态发酵生产过程,对工业化生产具有实际指导意义。 相似文献
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使用表面张力不同的纯水和乙醇作为液体,用氮气作为气体,在水平矩形微通道(dh = 0.29 mm)中开展两相流摩擦压降的实验研究,对通道进出口的压力进行了测量.结合流型说明了表面张力对摩擦压降产生的影响,并将实验压降值与均相流模型和分相流模型的预测值进行了对比,结果表明:在低压降区域,均相流模型预测值与实验值符合较好.... 相似文献
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采用φ3 mm×3 mm条状工业分子筛催化剂,在固定床管式反应器中考察了该催化剂在崁烯酯化制备乙酸异龙脑酯中的反应性能,建立了幂函数宏观动力学模型,运用最小二乘法进行动力学模型参数估计。结果表明,崁烯酯化制备乙酸异龙脑酯的表观活化能(Ea)为47.225 k J/mol,对崁烯和乙酸的反应级数分别为0.15和0.5。预测值与实验值能较好地吻合,表明动力学模型是适用的。 相似文献
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采用计算流体力学(CFD)方法,应用Euler-Euler双流体模型,桨叶采用多重参考系法(MFR),与考虑气泡聚并与破碎对气泡尺寸影响的群体平衡模型(PBM)相结合,比较了标准k-ε、Realizable k-ε和RNG k-ε3种湍流模型对双层涡轮搅拌釜内气-液两相液相流场、局部气含率及气泡尺寸分布的影响。结果表明:3种湍流模型预测的液相流场流型相似,总体气含率预测值相差不大,均与实验值吻合较好。对于局部气含率,标准k-ε和RNG k-ε模型在桨叶区的预测值偏大,在接近自由液面处三者预测值均偏低,Realizable k-ε模型预测结果与实验值符合最好;对于气泡尺寸,3种湍流模型预测结果均与实验值较吻合,在靠近自由液面处预测值均偏小,气泡尺寸分布与湍流长度分布相吻合。 相似文献
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引 言一个活细胞就是一个反应器[1] ,这一细胞反应器在一个高度复杂的有序调控系统操纵下发生上千个化学反应 ,其对外界环境的改变会产生能动反应 .目前文献中对细胞培养描述的模型大多是以群体细胞为对象的非结构和结构模型 ,而以单个细胞为对象的模型则很少[2 ] .近年来Cornell大学的Shuler研究小组以大肠杆菌为对象建立了一个详细的单细胞化学结构模型[3 ,4 ] ,该模型以单个细胞为对象 ,包含 2 0多种胞内组分和 50多个动力学方程 ,综合了大量的生物学信息 ,可以很好地模拟细胞对胞外营养成分的反应 .本文建立了一个比较简… 相似文献
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对长春花植物细胞团前10代粒径分布进行了研究,其平均粒径和分布的分散程度经历由大到小,再由小到大,最后达较稳定值的过程.针对模糊群子模型进行参数估计,拟合结果表明,植物细胞团粒径分布遵从能反映分散与成团矛盾作用的模糊群子模型. 相似文献
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环己醇、环己酮、二甘醇三组分汽液相平衡研究 总被引:1,自引:0,他引:1
用ROSE平衡釜测定了环己醇(1)-环己酮(2)、环己酮(1)-二甘醇(2)、环己醇(1)-二甘醇(2)3对二元系常压下的汽液相平衡数据,并对其进行了热力学一致性检验。用改进的Peng-Rob inson方程计算了气相逸度系数,用W ilson方程和NRTL方程分别计算了液相活度系数,拟合得到了模型参数。通过对实验数据进行关联,取得了较满意的结果:二元系实验数据与模型计算值的平均相对偏差在3%以内,三元系实验数据与模型计算值的平均相对偏差在4%以内。所关联的模型参数可靠,实验取得的相平衡数据可用于化工生产的设计、模拟与优化。 相似文献
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N. S. Ramesh Don H. Rasmussen Gregory A. Campbell 《Polymer Engineering and Science》1991,31(23):1657-1664
A new experimental technique for studying the dynamics of bubble growth in thermoplastics using scanning electron microscopy is developed. The influence of temperature, saturation pressure, molecular weight, and the nature of physical blowing agent are investigated. The experimental results show that, the above, process variables control the growth of foams during processing. The existing Newtonian model for the growth of a single bubble in an infinite amount of polymer has been modified to account for the non-Newtonian effects by modeling the polymer as a power law fluid. The experimental data has been compared with the appropriate viscoelastic cell model which considers the growth of closely spaced spherical bubbles during the foaming process. The simulation results indicate that the predictions of the cell model are in qualitative agreement with the trends of the experimental data and the quantitative agreement is reasonable. The cell model also gives an equilibrium radius which agrees with the experimental data. Other viscous models do not predict the equilibrium radius of the bubble and underpredict the experimental data. 相似文献
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Potential and current density distributions were modelled and measured for an electrochemical cell with a bipolar electrode.
The dimension of the bipolar electrode in the direction of current flow was extended, to enable experimental determination
of the electrode potential and the local current densities at various positions inside the electrolyte and in the electrode
body. The experimental results showed that the most active regions of the bipolar electrode are located at the ends of the
bipolar electrode facing the terminal electrodes. The equations corresponding to the mathematical model of the experimental
cell were solved using the finite volume method and gave very good qualitative agreement with the experimental data. However,
some discrepancies between model predictions and experimental data were evident in the active parts of the bipolar electrode
and in the variation of the terminal voltage with the total current. This was explained in terms of the active electrolyte
cross-section and the electrode surface area being diminished due to the presence of gas bubbles in the system. 相似文献
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Chrysovalantou Ziogou Spyros Voutetakis Michael C. Georgiadis 《Computers & Chemical Engineering》2011,35(9):1886-1900
The aim of this work is the development and experimental validation of a detailed dynamic fuel cell model using the gPROMS modeling environment. The model is oriented towards optimization and control and it relies on material and energy balances as well as electrochemical equations including semi-empirical equations. For the experimental validation of the model a fully automated and integrated hydrogen fuel cell testing unit was used. The predictive power of the model has been compared with the data obtained during load change experiments. A sensitivity analysis has been employed to reveal the most critical empirical model parameters that should be estimated using a systematic estimation procedure. Model predictions are in good agreement with experimental data under a wide range of operating conditions. 相似文献
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Solid oxide fuel cell (SOFC) is a key component in the new vision of distributed power generation. However, for connecting SOFC reliably to a load-varying grid, its transient behavior needs to be studied in detail with a thoroughly validated dynamic model. Dynamic models are also important for synthesizing efficient controllers. In this paper, a detailed dynamic model of a tubular SOFC is validated using experimental data from an industrial cell operating over a broad operating range. Steps in voltages and flows are used to study the system response. In the process of validation, phenomena that affect the transient response of the cell significantly are identified. The effects of Knudsen diffusion along with that of the increased active area for the electrochemical reactions are considered in this model observing the deviations of the simulation results from the experimental data. A dynamic model that includes these effects provides a very good match with the experimental data. Characteristics of the transient responses and various nonlinearities in the fuel cell dynamics are also studied in detail. 相似文献
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A continuous electrochemical process for bromine production from brine solutions was developed based on bromide oxidation
and flow-through porous electrode technology. The bromide oxidation kinetics in a three-dimensional porous graphite electrode
was determined using a small test flow cell. The data were analysed and combined into a process model to evaluate the electrode
performance under many different operating conditions. Bromide conversions against cell sizes for various brine throughputs
were calculated using model equations and verified by experimental data collected from a 45 cm long pilot cell. 相似文献