• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.873-880
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• 2017

To identify the feasibility of disposing of spent activated carbon as a clearance level waste, we performed characterization of radioactive pollution for spent activated carbon through radioisotope analysis; results showed that the C-14 concentrations of about half of the spent activated carbon samples taken from Korean NPPs exceeded the clearance level limit. In this situation, we selected thermal treatment technology to remove C-14 and analyzed the moisture content and thermal characteristics. The results of the moisture content analysis showed that the moisture content of the spent activated carbon is in the range of 1.2-23.9 wt% depending on the operation and storage conditions. The results of TGA indicated that most of the spent activated carbon lost weight in 3 temperature ranges. Through py-GC/MS analysis based on the result of TGA, we found that activated carbon loses weight rapidly with moisture desorption reaching to $100^{\circ}C$ and desorbs various organic and inorganic carbon compounds reaching to $200^{\circ}C$. The result of pyrolysis analysis showed that the experiment of C-14 desorption using thermal treatment technology requires at least 3 steps of heat treatment, including a heat treatment at high temperature over $850^{\circ}C$, in order to reduce the C-14 concentration below the clearance level.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.1083-1091
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• 1988

Vacuum brazing is the most modern brazing process and is at present, far from being completely understood. By brazing under high vacuum, in an atmosphere free of oxidizing gases, a superior product with greater strength, ductility and uniformity can be obtained. In this study, the influence of brazing parameters such as base metal characteristics, joint clearance and brazing time were described in relation to the metallurgical phenomena and shear strength of vacuum-brazed joints between carbon steels and 304 stainless steel (SUS 304) brazed by copper filler metal. In copper brazing of SUS 304 to a medium carbon steel(M.C.S) the columnar Fe-Cr-Ni-Cu-C alloy structure was formed and grew from the M.C.S side and at the same time, the surface of M.C.S. was decarbonized. The driving force for the formation and growth of columnar structure was the difference of carbon content between base metals. As the joint clearance is narrower and brazing time is longer, the formation and growth of columnar phase and decarburization of carbon steels were more noticeable. Because of decarburization of carbon steels, the shear strength of brazed joints were reduced as the formation of columnar structure was increased.

• Design & Manufacturing
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• v.6 no.2
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• pp.84-89
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• 2012

In recent years, technology of press plastic working having made remarkable progress. We can say this because it facilitates mass production and have superior performances in machining speed and equivalency of quality than other processing methods. In characteristics of press plastic working, mold manufacturing according to characteristics of each product should be preceded before processing and it has a great influence on machining speed and quality of products and etc according to manufacturing method. Therefore, mold design technology is a critical technology in press plastic working. There are lots of variables in press plastic working according to worked material, mold materials, conditions of heat treatment, clearance and so on. Abrasion of mold depends on these kind of conditions and sheared surface which is crucial for quality of product also depends on them. In this study, we conduct research on abrasion loss of mold according to 8, 10 and 12% of clearance for thickness of 1.0mm of worked material out of mold design variables of the products whose worked materials are high carbon steel and carbon tool steel by a practical experiment.

• Design & Manufacturing
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• v.6 no.2
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• pp.90-95
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• 2012

The sheet metal forming proceccing is very important and indispensable in the automotive industry because the accuracy of prsee worked parts is directly related to the automotive quality. But when making mold it is difficult and expensive to modify mold. mold design technology is a critical technology in press plastic working. When design the mold there are lots of variables in press plastic working according to worked material, mold materials, conditions of heat treatment, clearance and so on. Abrasion of mold depends on these kind of conditions and sheared surface which is crucial for quality of product also depends on them. In this study, we conduct research on abrasion loss of mold according to 8, 10 and 12% of clearance for thickness of 1.0mm of worked material out of mold design variables of the products whose worked materials are high carbon steel and carbon tool steel by a practical experiment and perform a comparative evaluation of difference of abrasion loss mold with the alloy tool steel (STD11) and Tungsten Carbide (WC).

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1283-1286
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• 2001

Effect of the egg yolks from laying hens intubated, p.o., astaxanthin (designated AEY) on mouse humoral immunity was investigated using male ICR mouse (6~7 weeks of age). Mice were adapted in a temperature- and humidity- controlled house for one week and randomly divided into 5 treatment groups (9 mice/cage/treatment). Mice were intubated p.o., AEY (100, 250 and 500$\mu\textrm{g}$) or control egg yolks (CEY, 250$\mu\textrm{g}$), dissolved in 0.1 mL DMSO, for consecutive 4 days. At day 5, carbon suspension (pilot drawing ink 3 mL+3% gelatine 3 mL) was injected 3 $\mu$L Per 1 g body weight through tail vein. Carbon clearance time was measured at 5 and 35 minutes Post the injection of carbon suspension. Another two experiments were conducted to determine the hemagglultinin-titer (HGT) and hemolysin-titer (HLT) with male ICR mouse (8 mice/cage/treatment). Mice treated with AEY were induced immune activity with SRBC. HGT and HLT were measured from the blood at day 1 and 3 after treatment of SRBC. AEY treatment reduced the carbon clearance time. Especially the carbon clearance time by 500 $\mu\textrm{g}$ AEY treatment was 5.00 minutes, which was very short time compared with 9.42 minutes by control and 9.01 minutes by CEY. AEY group showed slights higher values of HGT and HLT than CEY group and control. At day 1, HGT in control, 250$\mu\textrm{g}$ CEY and 250$\mu\textrm{g}$ AEY groups was 5.50, 5.63, and 6.00, respectively. Similiarly, HLT in control, 250$\mu\textrm{g}$ CEY and 250$\mu\textrm{g}$ AEY groups was 4.75, 5.38, and 5.50, respectively, at day 1. These results suggest that AEY exhibited immunity-enhancing effect.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.2
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• pp.191-198
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• 2015

In this study, the flow characteristics at the ventilation holes was analyzed by using numerical method when carbon composite brake disk was rotated at a constant speed. In order to ensure the validity of the analysis results, grid dependency test was performed by considering the accuracy and appropriateness, and 4mm mesh size was selected for decrease of the maximum error rate 63.6%. As a result, the outside air flows in the clearance between the disk and shaft in case of B model. whereas, the outside air flows in the clearance or the outlet of the ventilation holes in case of A and C models. And also average static pressure at the outlet was changed depending on shape of the ventilation holes and rotational speed of the disk in case of A and C models. Besides, in the B model, intake air according to the clearance goes with side surface of ventilation hole, and so increased by mean velocity of 4.64m/s and mean pressure of 0.58pa in the ventilation hole outlet, in case of disk rotational speed of 146.21rad/s.

• YAKHAK HOEJI
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• v.28 no.4
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• pp.207-215
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• 1984

Effects of Ssang Wha Tang (SWT), a blended Chinease traditional medicine, on the pharmacokinetics of sulfobromophthalein (BSP) in the rats of hepatic failure induced by carbon tetrachloride were examined. The disposition of plasma BSP in carbon tetrachloride-treated rats (Group I) and in carbon tetrachloride+SWT-treated rats (Group II) followed a three-compartment model, while those in control group followed two-compartment model. GOT, GPT level and some pharmacokinetic paramiters like plasma clearance but except distribution volume (Vdss) recovered in Group II compared to Group I. Therefore, SWT seemed to have an apparent restoring effect of hepatic function damaged by carbon tetrachloride treatment. From the fact that Vdss of BSP in Group II was considered as an one of the probable mechanisms. More intensive increase in BSP-free fraction ($f_p$) in Group II than that in Group I might also explain the increases of BSP clearance and Vdss in Group II compared to Group I. Assuming no changes in hepatic plasma flow(Q) in each group, hepatic intrinsic clearance($CL^h_{int}$) decreased in Group I did not recovered not at all in Group II. Therefore SWT seemed not to have any restoring effect of true hepaticfunction to biotransform and excrete BSP, and the apparent restoring effect of SWT might be due only to the replacement of BSP-plasma protein binding. Whether $f_p$ is actually higer in Group II than in Group I, and Q is constant in each group are being examined in our laboratory. The changes of Q, which might lead to another conculusions, also should be taken into consideration to clarify the apparent hepatorestoring effect of SWT.

• Korean Journal of Clinical Pharmacy
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• v.9 no.1
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• pp.55-61
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• 1999

The object of this work was to study the pharmacokinetic differences and the cause of these differences in cirrhotic rats induced by N,N-dimethylnitrosamine or carbon tetrachloride treatment when aminophylline (8 mg/kg as theophylline, i.v.) was injected. The concentrations of theophylline and its major metabolite (1,3-dimethyluric acid) in plasma were determined by HPLC. In addition, formation of 1,3-dimethyluric acid from theophylline in microsomes was determined. In cirrhotic rats, the systemic clearance of theophylline was reduced to $17\%$ of the control value while AUC (area under the plasma concentration-time curve) and $(t_{1/2})_{\beta}$ were increased to about 6 fold and 10 fold, respectively. The formation of 1,3-dimethyluric acid was decreased to $33-41\%$ of the control value in microsomes of cirrhotic rat liver. From these results, it can be concluded that in cirrhotic rats induced by N,N-dimethylnitrosamine or carbon tetrachloride the total body clearance of theophylline is markedly reduced due to a reduced hepatic metabolism.

• Journal of Food Hygiene and Safety
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• v.7 no.2
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• pp.91-97
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• 1992

Diazinon which is one of the most beavily used organophosphate pesticide in Korea, was examined for its effects on the murine host defense system. Immunotoxicological assay parameters adopted in this study were carbon clearance for macrophage function, susceptibility to tumor challenge, and pathotoxicological indicators, Subchronic exposure of pesticide to rodents resulted in the suppression of immune functions, enhancement of susceptibility to tumor challenge, and moderate histological changes of lymphoid organ without any significant alteration of clinical status.

• Natural Product Sciences
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• v.5 no.1
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• pp.54-59
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• 1999

Both ethanol and water extracts of unossified velvet antler were found to exhibit a significant immuno-stimulating activity as measured by carbon clearance test in mice, a remarkable anti-fatigue effect in weight-loaded forced swimming performance in mice, a significant anti-stress effect on immobilization in rats. The antler extracts also showed a weak but significant anti-thrombotic activity. These findings are indicative of adaptogenic properties of antlers and their normalizing effects during stressful condition.