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STUDY ON HARVESTED POPULATION WITH diffusional MIGRATION

Journal of Systems Science & Complexity 2001年第2期14卷 139-148页

作者： FAN Meng WANG Ke (Deportment of Mathematics, Northeast Normal University, Changchun 130024, China) ZHANG Yujuan ZHANG Shuwen LIU Huimin (Department of Mathematics, Anshan Teacher’s College, Anshan 114005, China) 东北师范大学吉林长春 130024 鞍山师范学院辽宁鞍山 114005

This paper is devoted to the study of the dynamical behavior and harvesting problem of an exploited population with diffusional migration, for which a protective patch is established. We examine the effects of protective patch and harvest on the population resources and conclude that the protective patch is effective for the conservation of population resources and ecological environment, though in some cases the extinction can not be eliminated. The dangerous region, the parameters domains and the typical bifurcation curves of stability of steady states for the considered system are determined. The optimal harvest policy for the considered population is made also. The explicit expressions are obtained for the optimal harvesting effort, the maximum sustainable yield and the corre- sponding population density. Our results provide a theoretical evidence for the practical management of biological resources.

关键词： Protective patch diffusional migration harvest.

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Mathematical Modelling for the diffusional Release of a Dispersed Solute from a Cylindrical Polymer Matrix into Finite External Volume

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Applied Mathematics 2012年第1期3卷 34-38页

作者： Thekkethil Shefeeq Naseem Ahmad 不详

An exact solution has been obtained for the release kinetics of a solute from a cylindrical non-erodible polymeric matrix into a finite external volume when the initial solute loading is greater than the solubility limit in the matrix. The moving boundary solution is derived based on the combination of variable method. The formulas of the moving boundary and the fractional solute release are given. The moving boundary and the fractional solute release profiles have been calculated at various solute loading levels and different external volumes. The obtained results show that as the external fluid volume increases, the fractional release at any time and the maximum fractional release increase. In addition, for a given external volume, as initial drug loading increases, the fractional release at any time decreases.

关键词： diffusional Release Kinetics Exact Solution Finite External Volume Mathematical Modeling

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Direct measurement of oxygen consumption rates from attached and unattached cells in a reversibly sealed, diffusionally isolated sample chamber

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Advances in Bioscience and Biotechnology 2010年第5期1卷 398-408页

作者： Timothy J. Strovas Sarah C. McQuaide Judy B. Anderson Vivek Nandakumar Marina G. Kalyuzhnaya Lloyd W. Burgess Mark R. Holl Deirdre R. Meldrum Mary E. Lidstrom Department of Electrical Engineering University of Washington Seattle USA.

Oxygen consumption is a fundamental component of metabolic networks, mitochondrial function, and global carbon cycling. To date there is no method available that allows for replicate measurements on attached and unattached biological samples without compensation for extraneous oxygen leaking into the system. Here we present the Respiratory Detection System, which is compatible with virtually any biological sample. The RDS can be used to measure oxygen uptake in microliter-scale volumes with a reversibly sealed sample chamber, which contains a porphyrin-based oxygen sensor. With the RDS, one can maintain a diffusional seal for up to three hours, allowing for the direct measurement of respiratory function of samples with fast or slow metabolic rates. The ability to easily measure oxygen uptake in small volumes with small populations or dilute samples has implications in cell biology, environmental biology, and clinical diagnostics.

关键词： Respirometry Oxygen Consumption Rate Reversible diffusional Seal Pt-Porphyrin

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KINETICS OF DIFFUSION-CONTROLLED DRUG MATRICES RELEASE SYSTEM

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Chinese Journal of Chemical Engineering 1993年第1期1卷 12-19页

作者：王绍亭杨志生朱云仙

A refined double integral method has been applied to the problem encountered in the diffu-sion release of a drug from a polymeric *** finite external mass transfer resistance has alsobeen incorporated into the present *** release rates of 5-fluorouracil fromethylene-vinyl alcohol copolymer into distilled water were measured in order to test the applicabilityof these *** system parameters were measured by experiments and models were built *** presented here are much more accurate than Higuchi model and much easier than the *** view of accuracy,the models are almost the same as the exact *** experi-mental release data agree Well with the computed

关键词： diffusional controlled release ethylene- vinyl alcohol copolymer release kinetics

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