• Fire Science and Engineering
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• v.12 no.1
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• pp.9-14
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• 1998

The hepatfluoropropane(HFC-227ea) synthesis by fluorinatino of hepafluoroproylene(HFP) over activated carbon has been studied. The reaction temperature was varied from 5$0^{\circ}C$ to 40$0^{\circ}C$ at a constant feed mole ration and a residence time. The optimized reaction temperature was found to be about 20$0^{\circ}C$ at 2.5HF/HFP mole ratio and 238 sec. residence time. From these reaction conditions, the yield of HFC-227ea was obtained above 99% and the deactivation of activated carbon was not appeared. Accordingly, the activated carbon showed good performance to obtain heptafluoropropane by fluorinatin of hexafluoropropylene.

• Analytical Science and Technology
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• v.24 no.2
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• pp.135-141
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• 2011

MMPs (Matrix metalloproteinases) are enzymes playing an important role to turnover and remodel main protein compositions of extracellular matrix. MMP-2 and MMP-9 of MMPs having a catalytic domain which is apart from a hemopexin-like domain part, are different from the other MMPs pertaining fibronectinlike domain close to hemopexin-like domain. It was reported that the development of MMP-9 restrainer can prevent the transfer of liver cancer. In this study, MMP-9 restrainers were extracted and purified from Hovenia dulcis Thunberg. The each fractionary part was examined to investigate the inhibitory effect on MMPs. Three compounds, compound A and B eluted with ethyl acetate (EA) and compound C with methanol, were identified by $^1H$ and $^{13}C$ NMR, GC/MS, and FT-IR. Compound A is considered as a kind of catechine type compound having a benzene ring substituted by hydroxyl and methoxyl groups. Compound B and C are nobiletin type compound pertaining a carbonyl group. Compound A, B and C showed 76%, 66% and 71% of inhibition effect on MMP-9 at 1.0% concentration, respectively. Compound A showed the best inhibition effect on MMP-9.

• Advances in pediatric surgery
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• v.9 no.1
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• pp.6-11
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• 2003

This study reviews 14 years' experience treating esophageal atresia with special emphasis on the clinical profile and outcome. From May 1989 to February 2003, 65 cases of esophageal atresia (EA) were treated at Asan Medical Center. Boys outnumbered girls 2.4 to 1. Prematutity and low birth weight were 27.7% and 38.5%. Esophageal atresia with distal tracheoesophageal fistula (TEF) was the most common type (87.7%), followed by pure EA and H type fistula. Forty-six patients (70.8%) had one or more associated anomalies, cardiac malformations were the most common. Duodenal atresia was found in 7 cases. There were 6 patients (9.2 %) with VATER cluster. VACTERL cluster was present in 18 patients (27.7%), one of who fulfilled the complete syndrome. Waterston group A, B and C made up 21.5%, 40.0% and 38.5% of the total group. Surgical treatment was attempted in 63 patients and deferred in 2 who had severe associated malformations. For EA with distal TEF, primary esophago esophagostomy was carried out in 51 cases, and division of TEF and gastrostomy in 4 cases and no operation in 2 cases. For pure EA, colonic graft was done in 2 after gastrostomy and esophagostomy, and esophago esophagostomy was performed in 2 after gastrostomy. Two patients with pure EA are waiting for the second operation after gastrostomy. Division of TEF was carried out in 2 cases with H type TEF. The overall survival rate was 76.9%, and survival by Waterston classification was 100% in group A, 80.8% in B and 60.0% in C. Thorough workup for associated anomalies, interdepartmental approach and more careful surgical decision and technique are required to improve the outcome of EA.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.525-530
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• 1989

In order to enumerate the T-lymphocytes in bovine peripheral blood lymphocytes (PBL) by E rosette assay, KGRBC were treated with various concentrations of 2-aminoethylisothiouronium bromide(AET) and dextran(Dex), singly or in combination. To further standardize the assay, optimum concentration of AET- and/or Dex-treatment and incubation time for rosette forming cell(RFC) counts were determined. The levels of B-lymphocytes in the PBL were evaluated by erythzocyte-antibody($EA_{Fc}$)- and erythrocyte-antibody-complement (EAC)-rosetting techniques. The results obtained were as follows; The PBL from 20 clinically normal Korean cattle were formed as low percentage of spontaneous E-rosette ($6.7{\pm}2.4%$) in control group, whereas in KGRBC treated with 0.1M AET for 20 minutes and 8% Dex were formed as $37.3{\pm}2.7%$ and $45.1{\pm}2.1%$, respectively. And the synergistic effects were noted no less than $66.5{\pm}5.6%$ when the KGRBC treated with 0.1M AET and 8% Dex subsequently and rate of RFR did not change significantly between 3~24 hours incubation time at $4^{\circ}C$, EA-and EAC-RFR were $23.3{\pm}9.1%$ and $23.1{\pm}7.9%$, respectively. These results suggest that the KGRBC would be a useful agent for the enumeration of T-lymphocytes by E rosette assay and B-lymphocytes by EA- or EAC-rosette assay in cattle-PBL.

• Journal of the Korean Professional Engineers Association
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• v.14 no.3
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• pp.9-21
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• 1981

The rationalization for Tunnel Drifting is based on the high productivity which is achievable due to Continuous work with a Jumbo Drill, resulting in a much higher efficiency them the Conventional method of blasting, mucking and supporting services. Large projects of over 4,000m Tunnel Drifting are condidated to justify the use of a Jumbo Drill with a combination of superior explosives, machinery and techniques. During a Tunnel Drifting test, Gulita, Nabit and slurry made by Nitro Nobel were employed with following results. 1, Conditions: a. Granite Rock with Two free face b. Burden (W), 2m c. Diameter of hole, 42mm d. Depth of hole 3.5m e. Hole pitch 0.6m f. Charged Explosive per hole Gelatin Dynamite 4 pieces (112.5${\times}$4ea)+Guuita 5 pieces(110g${\times}$5ea) g. Simal-taneous Detonation h. After the blasting resultant rock size was Less 40% of the 0.3m Lumps. 2. Calculation results W=q/Wn=100cm‥‥‥Burden in simultaneous blasting 0.865kg(7.7ea)/hole ‥‥‥Amount of charge but hole pitch is 1.5W-2W The estimated cost of using a Jumbo Drill for the Construction of a 3,000,000 bbL sub-surface oil storage would be as follows: This calculation is based on the Jumbo Drill advancing 3.6m per blasting cycle. Unit cost/bbL Excavation $3.13 The attached sheet shows ideal Drilling pattern with Burn Cut & Smooth blasting method. In conclusion, it is my opinion that this method will assure safety and save cost and improve our technical know-how.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.715-719
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• 2011

The $La_{0.7}Sr_{0.3}Cr_{1-x}Ni_{x}O_{3}$(LSCN-x) perovskites were prepared by citric acid and EDTA using a sol-gel method. The LSCN-x was characterized by BET, XRD, SEM, $H_2$-TPR, EA and TEM. The catalytic performance of LSCN-x catalysts in steam reforming of propane in the temperature range 600~$800^{\circ}C$ was investigated. Propane conversion and hydrogen yield increased with an increase in the amount of added Ni up to x=0.5 in the B-site, denoted as LSCN-0.5, under S/C=1 and S/C=1.7 reaction conditions. The LSCN-0.5 catalyst exhibited the best performance under Ni-substitution of which propane conversion and hydrogen yield was 100%, 95.9% at $800^{\circ}C$ in the S/C=1.7 condition, respectively. The morphology of carbon deposited on the catalysts after reaction exhibited filamentous carbon and amount of carbon deposited on the catalysts after reaction increased with an increase in the amount of added Ni.

• Applied Microscopy
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• v.27 no.2
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• pp.155-163
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• 1997

Ultrastructural and histochemical studies were carried out on the prostate gland of a Korean slug (Incilaria fruhstorferi) with light and electron microscopes. The results are as follows. The endothelial tissue of the prostate gland is constituted with tall and narrow ciliated columnar cells, irregularly shaped cells and gland cells in which are included the elongated oval or ellipsoid nucleus those are surrounded by curved membrane. The endothelial tissue of the prostate gland is composed by type-A, B, C and type-D gland cells, and the glanules of type-A, B, and D gland cells are certified to neutral mucopolysaccharide because are related by PAS-alcian blue (pH 2.5) , but the other hand type-C gland cell is only weakly reacted to PAS, but strongly reacted by Million reaction. The glanules of type-A gland cell are small size (about $0.4{\mu}m$) and are seen high electron density, but the glanules of type-B gland cell are large size (about $0.7{\mu}m$) and glanule density is same type-A glanules. Long ellipsoid type-C gland cell contained round nucleus which is well developed beterochromatin in, and that small oval glanules (size, about $0.9{\mu}m$) of moderate high electron density which are formed a group of large glanule together with $4\sim5ea$, but type-D gland cell possessed round small nucleus are seen high electron dense glanules (size, $0.8{\mu}m$).

• Bulletin of the Korean Chemical Society
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• v.18 no.6
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• pp.653-656
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• 1997

The new unsymmetric $N_6$ ligand 1-amino-13-(2-pyridyl)-3,6,9,12-tetraazatridecane (aptatd) containing one pyridyl group has been synthesized and characterized by EA, IR, and NMR. Its proton association constants $(log K_H^n)$ and stability constants $(log K_{ML})$ for Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ), and Zn(Ⅱ) ions were determined at 298.1 K and ionic strength 0.100 mol $dm^{-3}$ (KNO₃) in aqueous solution by potentiometry: log $K_H^1$=8.80, log $K_H^2$=8.49, log $K_H^3$=6.84, log $K_H^4$=4.17, log $K_H^5$=3.47; log $K_{ML}(Co^{2+})$=18.00, log $K_{ML}(Ni^{2+})$=21.31, log $K_{ML}(Cu^{2+})$=23.62, log $K_{ML}(Zn^{2+})$=15.60. The X-ray structure of its nickel(Ⅱ) complex [Ni(aptatd)]$(ClO_4)_2$ are reported: orthorhombic space group Pbca, a=15.715(1) Å, b=14.280(2) Å, c=19.443(2) Å, V=4363.4 (9) ų with Z=8. The geometry around nickel is a distorted octahedron with the pyridine nitrogen atom being cis to the nitrogen atom of the terminal primary amine.

• Korean Journal of Plant Resources
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• v.27 no.5
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• pp.588-592
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• 2014

A new Saxifraga fortunei cultivar 'Whitegreen' was bred by crossing between 'Daewoojoo' with Pale Green (Y-G145-C) colored petals and 'Kwanglim' with light Yellow green (Y-G145A) colored petals. The selection and flower characterization were conducted from 2004 to 2008 in greenhouse of Highland Agriculture Research Center, NICS, RDA. Flowering in 'Whitegreen' Showed from September 20 th for 33 days. The number of petals were 11.4 ea., with a width of 1.4 cm and length of 1.4 cm. The plant height was 20.7 cm, and number of leaves per plant was 48.3 ea., with a width of 3.4 cm and length of 3.0 cm. 'Whitegreen' cultivar can be used as a pot flower. 'Whitegreen' plants grown under 50% shade of sunlight have higher degree of acclimation compared to those under direct sunlight. And soft rot disease would occur usually by over-irrigation. 'Whitegreen' cultivar was registered as a novel variety with No. 3456 in Korea seed and variety service on April 2011.

• Korean Journal of Food Science and Technology
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• v.47 no.1
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• pp.56-62
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• 2015

Various pretreatment methods were evaluated to prevent tissue softening of heated onion. Changes in onion tissue firmness during heating were explained by 3-mechanism model consisting of texture hardening at low temperature ($60-80^{\circ}C$) and substrate softening at high temperature. Preheating of onion in a $Ca^{2+}$-containing solution significantly improved its texture after high-temperature heating. The improvement of firmness by preheating at low temperature was related to the formation of strong cross-linking between carboxyl groups and $Ca^{2+}$ by the action of pectin methylesterase in onion. The highest firmness was obtained by pre-heating at $70^{\circ}C$ for 120 min in 0.5% calcium solution. This result was supported by chemical analysis showing that the amount of bound calcium was the highest at $70^{\circ}C$. Further investigation should be carried out to establish the optimal conditions to prevent the softening of various vegetables.