• Journal of Pharmaceutical Investigation
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• v.30 no.2
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• pp.99-105
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• 2000

This study compared the permeability of $[^3H]taurine,\;[^3H]phenylalanine,\;and\;[^3H]oxytocin$ through the blood-brain barrier (BBB) in mice and rats with common carotid artery perfusion (CCAP) method that modified internal carotid artery perfusion (ICAP) method. External carotid artery (ECA) was cannulated with coagulating pterygopalatine artery (PPA) in ICAP method, while CCA was cannulated without coagulating PPA in CCAP method. Also, for evaluation of BBB permeability of drugs in mice and rats, we used intravenous injection technique. The results of CCAP method in mice at a perfusion flow-rate of 2 ml/min, the brian volume of distribution $(V_D)$ of $[^{14}C]sucrose,\;[^3H]taurine,\;[^3H]phenylalanine,\;and\;[^3H]oxytocin$ were similar to the result of ICAP method in rats at perfusion flow rate of 4 ml/min. The area under the plasma concentration-time curve and brain uptake of $[^3H]taurine$ by intravenous injection technique, were $65.5{\pm}9.7%ID^*min/ml\;and\;0.515{\pm}0.093%ID/g$, respectively, in mice, and the corresponding values were $8.00{\pm}0.03%ID^*min/ml\;and\;0.052{\pm}0.003%ID/g$ in rats. But the BBB permeability surface-area product of $[^3H]taurine$ was similar between mice and rats. In conclusion, the CCAP method in mice was simple, fast and comparable to ICAP method in rats for drug permeability through the BBB.

• Geomechanics and Engineering
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• v.18 no.2
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• pp.205-213
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• 2019

A calculation model of reservoir pressure field distribution around multiple production wells in a heavy oil reservoir is established, which can overcome the unreasonable uniform-pressure value calculated by the traditional mathematical model in the multiwell mining areas. A calculating program is developed based on the deduced equations by using Visual Basic computer language. Based on the proposed mathematical model, the effects of drainage rate and formation permeability on the distribution of reservoir pressure are studied. Results show that the reservoir pressure drops most at the wellbore. The farther the distance away from the borehole, the sparser the isobaric lines distribute. Increasing drainage rate results in decreasing reservoir pressure and bottom-hole pressure, especially the latter. The permeability has a significant effect on bottom hole pressure. The study provides a reference basis for studying the dynamic pressure field distribution before thermal recovery technology in heavy oilfield and optimizing construction parameters.

• Tunnel and Underground Space
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• v.12 no.4
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• pp.304-311
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• 2002

This study reports the influence of vocid geometry on fracture closure and permeability from numerical experiments. As the aperture distributions of rock fractures are characterized by statistical methods, synthetic fractures have successfully been simulated in this way. Based on the generated fracture models, models for fracture closure and flow calculation have been developed. A fracture closure model has been developed by considering the asperity compression and half-space deformation, and flow calculations have been performed using a finite difference method adopting a local cubic law. The results of numerical experiments have shown that the increase in the aperture spatial correlation leads the fracture closure and the decrease in fracture permeability to increase. Also, it has been indicated that there is an implicit relation between fracture normal stiffness and permeability. The importance of this study is to enhance the understanding the hydro-mechanical behavior of fractured rock massed due to engineering projects.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.511-512
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• 2007

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2004.11a
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• pp.64-64
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• 2004

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2773-2784
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• 2023

It is essential to evaluate the blasting-enhanced permeability (BEP) feasibility of a low-permeability sandstone-type uranium deposit. In this work, the mineral composition, reservoir physical properties and rock mechanical properties of samples from sandstone-type uranium deposits were first measured. Then, the reformability evaluation method was established by the analytic hierarchy process-entropy weight method (AHP-EWM) and the fuzzy mathematics method. Finally, evaluation results were verified by the split Hopkinson Pressure Bar (SHPB) experiment and permeability test. Results show that medium sandstone, argillaceous sandstone and siltstone exhibit excellent reformability, followed by coarse sandstone and fine sandstone, while the reformability of sandy mudstone is poor and is not able to accept BEP reservoir stimulation. The permeability improvement and the distribution of damage fractures before and after the SHPB experiment confirm the correctness of evaluation results. This research provides a reformability evaluation method for the BEP of the low-permeability sandstone-type uranium deposit, which contributes to the selection of the appropriate regional and stratigraphic horizon of the BEP and the enhanced ISL of the low-permeability sandstone-type uranium deposit.

• Journal of Soil and Groundwater Environment
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• v.22 no.3
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• pp.42-49
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• 2017

TOUGH2 was used to simulate the migration of $CO_2$ injected into a sandy aquifer. A series of numerical simulations was performed to investigate the effects of a low-permeability layer (LPL) embedded in the aquifer on the injection rate and the pressure distribution of $CO_2$. The results show that the size and location of the LPL greatly affected the spread of $CO_2$. The pressure difference between two points in the aquifer, one each below and above the LPL, increased as the size of the LPL increased, showing a critical value at 200 m, above which the size effect was diminished. The location of the LPL with respect to the injection well also affected the migration of $CO_2$. When the injection well was at the center of the LPL, the injection rate of $CO_2$ decreased by 5.0% compared to the case with no LPL. However, when the injection well was at the edge of the LPL, the injection rate was decreased by only 1.6%. The vertical distance between the injection point and the LPL also affected the injection rate. The closer the LPL was to the injection point, the lower the injection rate was, by up to 8.3%. Conclusively, in planning geologic storage of $CO_2$, the optimal location of the injection well should be determined considering the distribution of the LPL in the aquifer.

• Geophysics and Geophysical Exploration
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• v.6 no.2
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• pp.64-70
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• 2003

A new approach of estimating the coefficient of permeability (COP) from resistivity has been developed, which can provide another good application tool of geophysical methods to geo-technical field. Borehole electrical logging and Lugeon test results in Yangsan area showed that resistivity is inversely proportional to the COP. For granite and andesite in Yansan area, the relation between the resistivity ($\rho$) and the COP (k) revealed that, $log(k){\approx}-0.85621\;log({\rho})+0.0031$. Derived relation is applied to AMT data acquired from a survey line along the tunnel. Two-dimensional resistivity distribution from AMT data was converted to two-dimensional COP section. The final COP section can be used as good input data for groundwater modeling.

• Journal of the Korean Wood Science and Technology
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• v.31 no.1
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• pp.61-70
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• 2003

The size distribution of the free water paths between earlywood and latewood for six species in the heartwood of softwoods was estimated from the amount of dehydrated free water under various centrifugal fields, such as 2,200, 3,300, 4,800 and 6,900 rpm. The centrifugal method is based on the concept that water movement occurs by the balance of centrifugal force and water potential by meniscus. Water stops where the pressure differential is zero. In the centrifugal field, only two factors affect water movement in wood, that is, centrifugal force and water potential. Also, the water permeability was evaluated from the relationship between the water saturation ratio after the centrifugal treatment and the measure of water potential in specimen. The results showed that Cryptpmeria japonica had clear peaks at 0.70 ㎛ in earlywood and at 0.50 ㎛ in latewood. Tsuga sieboldii and Larix kaemferi had peaks at 0.50 and 0.30 ㎛ in both earlywood and latewood, respectively. Abies firma showed peaks at 0.70 ㎛ in earlywood and at 0.30 ㎛ in latewood. The water permeability of earlywood was higer than that of latewood for all softwoods except Pseudotsuga menziesii.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.609-612
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• 2001

To investigate the magnetic field distribution of power line, we used amorphous wire sensor. And we discuss extremely low frequency magnetic field distribution dependent upon arrangement of power line and shielding pipe made from iron or alumimum materials by both measurement and FEM(Finite Element Method) analysis. Appling current of single phase 60 [Hz] 15 [A] is supplied to copper wire coated enamel resign. As the results, we confirmed that linear characteristics of amorphous wire sensor is very excellent and measurement value agrees with FEM calculation. Magnetic field distribution due to shielding materials is changed by permeability and conductivity.