• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.676-683
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• 2003

A laboratory experiment using artificial fracture rocks was used to understand the 3-dimensional dispersion of a tracer and the mixing process in a fractured network. In this experiment, 12cm polystyrene foam cubes with two electrodes for monitoring electric conductivity (EC) were used as artificial fractured rocks. Distilled water with 0.5mS/m was used as a tracer in water with 35mS/m and the difference of EC between the tracer and the water was monitored by a multipoint simultaneous measurement system of electrical resistance. The results showed that even if the fracture arrangement pattern was not straight in the direction of the flow, the tracer did not diffuse along individual fractures and an oval tracer plume, which was the distribution of tracer concentrations, tended to be form in the direction of the flow. The vertical cross section of the tracer distribution showed small diffusivity in the vertical direction. The calculated total tracer volume passing through each measurement point in the horizontal cross section showed while that the solute passed through measurement points near the direction of hydraulic gradient and in other directions, the passed tracer volumes were small. Using Peclet number as a criterion, it was found that the mass distribution at the fracture intersection was controlled in the stage of transition between the complete mixing model and the streamline routing model.

• Journal of The Korean Society of Clinical Toxicology
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• v.1 no.1
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• pp.6-11
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• 2003

Various forms of dialytic techniques are available for detoxification. Hemodialysis, hemoperfusion and hemofiltration (hemodialfiltration) are the main treatment modalities. Because these modalities are rather invasive and expensive, it must be decided in balance of the risk and benefit to the patient. The prime consideration in the decision is based on the clinical features of poisoning; hemodialysis or hemoperfusion should be considered in general if the patient's condition progressively deteriorates despite intensive supportive therapy. The hemodialysis technique relies on passage of the toxic agent through a semipermeable membrane so that it can equilibrate with the dialysate and subsequently removed. It needs a blood pump to pass blood next to a dialysis membrane, which allows agents permeable to the membrane to pass through and reach equilibrium. Solute (or drug) removal by dialysis has numerous determinants such as solute size, its lipid solubility, the degree to which it is protein bound, its volume of distribution etc. The technique of hemoperfusion is similar to hemodialysis except there is no dialysis membrane or dialysate involved in the procedure. The patient's blood is pumped through a perfusion cartridge, where it is in direct contact with adsorptive material (usually activated charcoal) that has a coating material such as cellulose. This method can be used successfully with lipid-soluble compounds and with higher-molecular-weight compounds than for hemodialysis. Protein binding does not significantly interfere with removal by hemoperfusion. In conclusion, hemodialysis, hemoperfusion and hemofiltration can be used effectively as adjuncts to the management of severely intoxicated patients.

• Journal of the Korean Chemical Society
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• v.32 no.5
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• pp.483-494
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• 1988

The adsorption behavior of aromatic acids on Amberlite XAD-4 resin was investigated by measuring the distribution coefficient by batch method. The adsorption of solutes on XAD-4 was affected by the several factors such as, analyte concentration, the pH of solution and concentration of pairing ion. The enhanced adsorption of solutes on XAD-4 in the presence of tetraalkylammonium salt as an ion pairing reagent, referred to as ion interaction, was suggested to follow a double layer model where the pairing ion occupies a primary layer at the adsorbent while the solute anion and other anions in the system comlpete for the secondary layer. Therefore, the ability of an ion pairing reagent to enhance solute adsorption depended significantly on the type and concentration of counter-ion and co-anion accompanying the ion pairing reagent or salt used for ionic strength control. In addition, a good linear relationship between the logarithm of capacity factors measured by batch and elution method as a function of the concentration of ion pairing reagent and methanol can be used to predict the retention in elution method on the basis of capacity factors measured by batch method.

• Fisheries and Aquatic Sciences
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• v.8 no.1
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• pp.10-16
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• 2005

Conditions for sufficient and rapid distribution of a cryoprotectant (sorbitol solution) into intact fish muscle (Oncorhynchus mykiss) were studied as changing in the residual Ca2+ ATPase activity during freeze/thaw cycling. Chunks of the fish muscle were immersed in 4 concentrations of sorbitol solutions ($20\%$, $30\%$, $45\%$, and $60\%$) by a shaker mechanism at 5$^${circ}C. Whole immersion samples (W) showed a higher value of the residual Ca2+ ATPase activity than those in the untreated controls (C), except in the treated controls (TC), while less effect of immersion concentration could be found. Comparing the extent of penetration of sorbitol into the surface layer to inner layer of immersed fish chunks, outer portion samples achieved excellent cryoprotection with $100\%$ of the residual ATPase activity values or more. For the inner portion samples, $30\%$ and $45\%$ sorbitol solution treatments indicated a higher ATPase activity than $60\%$ treatment. At high concentrations, mass transfer rates during osmotic dehydration might berapid and it causes faster surface drying by dewatering at surface solute layer. Periodically immersed and relaxed samples, W (5-3-1), led to good cryoprotection effect: W (5-3-1) indicated high residual Ca2+ ATPase activity values and the residual ATPase activity values excess $100\%$ in immersion of $30\%$ and $45\%$ sorbitol solutions.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.1
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• pp.19-31
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• 1996

To invetigate the impurity distribution in GaAs crystal grown by horizontal Bridgman method, we constructd the mathematical model describing heat transfer, mass transfer and fluid flow n transient growth of GaAs. Galerkin finite element method and implicit time integration were used to solve the equations and simulate the transient growth. The concentration distribution is similar to the case of diffusion controlled growth when Gr - 0. With the increase of Gr the concentration profile is distroted and the minimum solute concentration appears near the interface. As solidification prosceeds, interface deflection increases steadily and transverse segregation increases until mixing by flow becomes steady. The axial segregation increases with solidification. But, with high intensity of flow axial segregation becomes steady after short transient. At small and large Gr the result showed a good agreememt with the prediction Smith and Scheil.

• Textile Coloration and Finishing
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• v.6 no.4
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• pp.40-45
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• 1994

To improve the blood compatibility of cellulose membrane, 2-(methacryloyloxy)ethyl-2-(trimethylammonium)ethyl phosphate(MTP), which is a methacrylate with phospholipid polar group, and glycidyl methacrylate(GMA) were grafted simultaneously on the surface of membrane and the biocompatibility of grafted membrane was investigated. There was no difference of permeability between the MTP and GMA-grafted and the original cellulose membrane. The permeation pathway for a solute whose molecular weight was above 10$^{4}$ is maintained after grafting on the surface of membrane. The cellulose membrane grafted with MTP and GMA effectively suppressed thrombogenicity for the rabbit blood. This effect became more clear with increasing the surface distribution of phospholipid polar groups.

• Journal of Environmental Science International
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• v.7 no.6
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• pp.753-759
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• 1998

In physical and reactive extraction of acrylic acid using various solvents the equilibrium characteristics of extraction were investigated. The degree of extraction in reactive extraction with Tri-n-octylamine(TOA) was 1.5~3 times than that in physical extraction. Distribution ratio was constant in methyl isobutyl ketone(MIBK) and n-butylacetate(n-BAc) but was increased with increasing the concentration of acrylic acid in benzene and chloroform. It can be explained by formation of dimers. Maximum extraction leadings of acrylic acid were three in benzene and were two in MIBK, chloroform and n-BAc, and it was found that acrylic acid was extracted as the form of $A_3$R In benzene and $A_2R$ in MIBK, chloroform and n-BAc. In effect of solvent, the degree of extraction was increased as he difference of solubility parameter of solvent and solute was decreased, and as dielectric constant of solvent was increased.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.399-421
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• 1996

(1) The solute distribution mechanism was analyzed for the Si0.95Ge0.05 single crystal fiber by u-PD method. (2) The steady-state solutions were obtained for the molten zone and the capillary zone. (3) The effect of the convection in the molten zone on partitioning was not significant for many cases. (4) Intermediate transient rise of Ge was shown by the sudden change of the growth velocity or molten zone height. (5) Periodic compositional modulation can be designed by using the intermediate transient.

• Corrosion Science and Technology
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• v.9 no.2
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• pp.67-73
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• 2010

Niobium microalloying is effective in hot-rolled and cold-rolled steels by providing a fine-grained microstructure resulting in increased strength. To optimize the strengthening effect, alloy design and hot-rolling conditions have to be adapted. As a key issue the dissolution and precipitation characteristics of Nb are discussed in particular with regard to the run-out table conditions. It is then considered how the hot-rolled microstructure and the solute state of Nb interact with the hot-dip galvanizing cycle. The adjusted conditions allow controlling the morphology and distribution of phases in the cold-rolled annealed material. Additional precipitation hardening can be achieved as well. The derived options can be readily applied to produce conventional HSLA and IF high strength steels as well as to modern multiphase steels. It will be explained how important application properties such as strength, elongation, bendability, weldability and delayed cracking resistance can be influenced in a controlled and favorable way. Examples of practical relevance and experience are given.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1120-1125
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• 2004

Welding characteristics of STS304 stainless steel and Inconel 600 using a continuous wave Nd:YAG laser are experimentally investigated. Alloy 600 being used in steam generator tubing of pressurized water reactor(PWR) exposed to some corrosion environment, stress corrosion cracking can occur on this material. Presented here are the results from a series of experiments in which dissimilar metal welds were made using the gas tungsten arc welding process with pure argon shielding gas. But It is well known that solidification cracking susceptibility of austenitic alloys depends on the solidification temperature range and amount/distribution of solute rich liquid that exists at the terminal stages of solidification. An experimental study was conducted to determine effects of welding parameters and to optimize those parameters that have the most influence on eliminating or reducing the extent welding zone formation at dissimilar metal welds.