• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.2
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• pp.179-185
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• 2011

A marine collision accident occurred at the Jin-do water way. A barge loaded with heavy equipment of Power Generation Plant was being towed at its side by two tugs "A" and "B" from Byeg-pa harbour to the designated position to be used for power generation plant near Jin-do bridge. The Power Generation Plant was 40-meters high loaded atop the barge. When the "tugs and tow" were approaching the Jin-do the bridge, the two towing tugs lost maneuvering control of the barge and it went off-course, hit first the waterway embankment and finally struck the lower part of bridge's span and post musing the barge to capsize and sunk its cargo into the sea. The bridge also suffered damages where the top of the Plant struck At the time of the accident, there was a strong tidal current at the waterway. This paper calculates the safe towing force of barges with heavy loads when traversing in a strong tidal current situation in narrow waterway.

• Polymer(Korea)
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• v.26 no.4
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• pp.477-482
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• 2002

In order to control the micro-pore structure of glassy carbon (GC), an activation agent of KOH was introduced as the glassy carbon was prepared from phenolic resin with a curing agent of phosphoric acid. The yield and properties of GC were investigated as a function of KOH content. Although the GC produced without KOH had nonporous structure except the trace of bubble formation, the GC with KOH had very porous structure. The surface area of GC with KOH increased continuously up to 870 $m^2$/g with the increase of KOH content. The carbonization yield and apparent density measured in water reduced from 40 to 15% and iron 1.5 to 0.9 g/$cm^3$, respectively, and the electrical resistivity increased from $50{\times}10^{-4}$ to $60{\times}10^{-4}$$\Omega$.cm with the increase of KOH content.

• Nuclear Engineering and Technology
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• v.36 no.4
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• pp.346-356
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• 2004

14 Pressurized Water Reactors (PWR) in Korea use a remote monitoring system (RMS), which have been used in Korea since 1998. A Memorandum of Understanding on Remote Monitoring, based on Enhanced Cooperation on PWRs, was signed at the 10th Safeguards Review Meeting in October 2001 between the International Atomic Energy Agency (IAEA) and Ministry Of Science and Technology (MOST). Thereafter, all PWR power plants applied for remote monitoring systems. However, the existing method is high cost (involving expensive telephone costs). So, it was eventually applied to an Internet system for Remote Monitoring. According to the Internet-based Virtual Private Network (VPN) applied to Remote Monitoring, the Korea Atomic Energy Research Institute (KAERI) came to an agreement with the IAEA, using a Member State Support Program (MSSP). Phase I is a Lab test. Phase II is to apply it to a target power plant. Phase III is to apply it to all the power plants. This paper reports on the penetration testing of Phase I. Phase I involved both domestic testing and international testing. The target of the testing consisted of a Surveillance Digital Integrated System (SDIS) Server, IAEA Server and TCNC (Technology Center for Nuclear Control) Server. In each system, Virtual Private Network (VPN) system hardware was installed. The penetration of the three systems and the three VPNs was tested. The domestic test involved two hacking scenarios: hacking from the outside and hacking from the inside. The international test involved one scenario from the outside. The results of tests demonstrated that the VPN hardware provided a good defense against hacking. We verified that there was no invasion of the system (SDIS Server and VPN; TCNC Server and VPN; and IAEA Server and VPN) via penetration testing.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.30 no.2
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• pp.100-111
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• 2017

Objectives : The purpose of this study was to research the antibiotic, antioxidant and whitening effects of Jwa Kum-Whan(JKW) and Soo Ryeon-Whan(SRW). Both Jwa Kum-Whan and Soo Ryeon-Whan are composed of Coptidis rhizoma and Evodiae fructus, but the ratios of the two species are different. JKW is composed of Coptidis rhizoma and Evodiae fructus by ratio of 6:1 and SRW's ratio is 1:1. Methods : Antibiotic activities of JKW and SRW's water extracts were studied by paper disc diffusion method. Four kinds of bacteria were applied in paper disc, and each extract was dropped, individually. The diameter of inhibition zone was measured. DPPH assay was used for studying free radical scavenging activity. DPPH is quantitatively decolorized from purple color by antioxidant material. Change of color was measured by spectrophotometer. Whitening activity was analyzed by tyrosinase inhibition assay. Tyrosinase is major enzyme for control process of making eumelanin. Optical Density was measured by spectrophotometer. Results : Candida albicans and Staphylococcus aureus's inhibition zone were made large available by Both prescriptions. Inhibition zone's diameter of JKW was preferable to SRW's. Radical scavenging activity was better at SRW, but JKW's activity was available, too. Tyrosinase inhibition activity was found out available only for JKW, not for SRW. Conclusions : JKW had antibiotic effects for Candida albicans, Staphylococcus aureus. And had antioxidant, whitening effects. SRW had antibiotic, antioxidant activities but not whitening effect.

• Journal of the Speleological Society of Korea
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• v.59
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• pp.21-36
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• 1999

Most scholars calssify caves into natural resource, but caves possess values of natural and human resource, mix up the features of natural resources and human resources. Now, caves are distributed 260 in Korea. Seongryu Cave is showed in 1967 for the first time, till 1997 12 caves is opened to tourist. But since 1996 the 12 show caves of all is not launched the safety and environment-protection check-up adduced reason for IMF. Then caves must maintain environment of the normal temperature, humidity and dark. But the environment of caves are destroyed by tourism development. Thus to maintain environment of caves, it used to consider the counterplan as follows in restraint of the environmental change. Firstly, in case of development work to open caves, it must keep up with the prototype. Secondly, it must establish a freight depositary to prevent the influence of the caves's stain and damage due to tourist's objects. Thirdly, to maintain the normal temperature and humidity, it must install artificial poultice equipment of the inner parts of caves. Fourthly, in order to prevent the occurrence of $CO_2$, it must assessment of the optimum number of the greatest stayer. Fifthly, the control of closure for a given period of time is useful of the restoration to the cave's original state. Sixthly, by means of make narrow entrance, it should not influence the outer's air on the inner parts on caves. Seventhly, to keep the temperature of the inner part of caves, the lightening should be maintained moderately considering the convenience of a tour. Eightly, when water-proof cables for the lightening bulbs are connected each other, silicon tape is suitable and circuit breakers should be installed at the diverging points of the cables. Ninthly, the direction and angle of the lightening must be changed periodically to prevent green-pollution at the lightening spot. Lastly, when facilities and arrangements are equipped, corrosive materials should be excluded if circumstances allow.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.12
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• pp.842-849
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• 2007

For a $CO_2$ two-stage twin rotary compressor used for heat pump water heater system, changes of $CO_2$ solubility in PAG oil were investigated along the gas passages from the first stage suction to final discharge. Only slight changes in solubility took place in suction chambers for both of the first and second stages, but for compression chambers, solubility variation ranged from 0.115 to 0.136, and from 0.133 to 0.182, respectively for the first and second stages. Calculation of gas flashing in parts of leakage oil flows and of oil contained in control volumes due to solubility changes was conducted and included in gas pressure calculation. For the second stage, gas flashing amounts to around $5%\sim6%$ for most leakage flows. Cooling capacity, compressor input, and COP obtained by calculation were well compared to the experimental results. Effects of operation speed on the compressor performance was also studied: as the shaft speed increased, adiabatic efficiency decreased rapidly due to increased over-compression loss.

• Journal of Ginseng Research
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• v.30 no.3
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• pp.100-105
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• 2006

Liver and kidney are specific organs which play an active role in biotransformation and detoxification mechanisms. Ant adverse effect of chemicals or heavy metal can cause the delay or fade in these mechanisms. Present study was designed to find out the protective effect of Panax ginseng extract on renal functions altered by mercuric chloride (heavy metal) in albino rat. Fifty albino rats were divided into 10 groups. Five groups for acute study and five groups for sud-acute study viz. control group (Tween 20 and distilled water), mercuric chloride treated group (0.926 mg/kg body wt. for acute and 0.044 mg/kg body wt. for sub-acute group after calculated $LD_{50}$ (9.26 mg/kg body wt.) by probit analysis (Finney, 1971), Panax ginseng extract treated group (10 mg/kg body wt. for acute and sub-acute sets), mercuric chloride treated followed by Panax ginseng extract and Panax ginseng extract followed by mercuric chloride group. All doses were given orally by gavage tube. The result revealed that the serum urea and creatinine significantly increased in mercuric chloride treated group, while significantly decreased (p<0.01) in Panax ginseng extract group after acute and sub-acute treatment. The biochemical estimation is also confirmed by nephropathological aspect. However, the Panax ginseng extract treated followed by mercuric chloride group is more prominent than the mercuric chloride treated followed by Panax ginseng extract group. It can be concluded that Panax ginseng extract had a protective nature on renal functions against mercuric chloride toxicity in albino rats.

• Food Science and Preservation
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• v.7 no.3
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• pp.321-325
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• 2000

This study was conducted to investigate the effect of the extracts (water, 70% ethanol and ethylacetate) from dandelion (Traxancum platycarpum D.) leaf and root on the inhibitory activities of Leuconostoc mesenteroides, Lactobacillus brevis, Lactobacillus plantarum and Lactobacillus acidophilus. And also, the amounts of gas formation from kimchi with different concentration of the ethylacetate extracts (EE) were analyzed. EE of dandelion leaf inhibited the growth of Leuc. mesenteroides and L. acidophilus, and L. brevis by 50 and 33% at concentration of 0.5%, respectively. But no affected in L. plantarum estimated by pH, acidity, turbidity and clear zone. And no difference was founded in leaf and root. Gas was formed from the soaking day to 5-6 days of fermentation at $20^{\circ}C$, and the accumulated gas volumes were 80 ml/100 g in control, 30 ml/100 g in 0.5% EE, 8 ml/100 g in 1.0% EE.

• Korean Journal of Plant Resources
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• v.19 no.3
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• pp.385-391
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• 2006

In vitro-grown axillary buds of Melia aredarach were successfully cryopreserved by vitrification. On the MS medium supplemented with BA 1 mg/L, multiple shoots were developed within $4{\sim}5$ weeks. Plantlets of Melia azedarach were cold-hardened at $10^{\circ}C$ for a 16-hr photo-period for 6 weeks. Excised axillary shoot-tips from hardened plantlets were precultured on a solidified Murashige & Skoog agar medium (MS) supplemented with 0.7 M sucrose for 1 day at $25^{\circ}C$. Axillary shoot-tip meristems wert dehydrated using a highly concentrated vitrification solution (PVS2) for 60 min at $0^{\circ}C$ prior to a direct plunge into liquid nitrogen (LN). The PVS2 vitrification solution consisted of 30% glycerol (w/v), 15% ethylene glycol (w/v), 15% DMSO (w/v) in MS medium containing 0.4M sucrose. After short-term warming in a water bath at $40^{\circ}C$, the meristems were transferred into 2 ml of MS medium containing 1.2M sucrose for 15 min and then planted on solidified MS culture medium. Successfully vitrified and warmed meristems resumed growth within 2 weeks and directly developed shoots without intermediary callus formation. The survival rate of cold-hardened plantlets for 3 and 4 weeks was 90%. We did not find any difference in PCR-band patterns between control and cryopreserved plants. This method appears to be a promising technique for cryopreserving axillary shoot-tips from in vitro-grown plantlets of Medicinal plants.

• Archives of Pharmacal Research
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• v.24 no.2
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• pp.144-149
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• 2001

N-acetylsphingosine (C2-ceramide) is a synthetic water-soluble ceramide mimicking the activity of natural ceramides. By fixing chiral conformation on carbon numbers 2 and 3 in the ceramide structure, four chiral C2-ceramides naming d-erythro-, I-erythro-, d-threo-and 1-three C2-ceramide were synthesized. We have investigated the chiral effects of these C2-ceramides on the sphingolipid metabolism, particularly on both the sphingolipid bio- synthetic pathway and on the degradation pathway. In both HL-60 and U937 cells, the chiral C2-ceramide ($10{\mu}\textrm{m}$) showed sphingosine accumulation monitored fluoromatrically by a high performance liquid chromatographic separation of the sphingoid bases. Most importantly, in HL-60 cells, l-erythro C2-ceramide induced a 50 fold increase in sphingosine as compared to the control, while l-threo C2-ceramide exhibited a minimal 7-fold in-crease. In contrast, sphinganine, another sphingoid base, showed less accumulation by any chiral C2-ceramide tested under the same conditions. These results suggested that chiral C2-ceramide primarilyacts on the sphingolipid degradation pathway rather than on the sphingolipid biosynthetic route. The strong $C_0/G_1$ phase arrest in the cell cycle by treatment of I-erythro C2-ceramide indicates that the blockade of the sphingolipid degradation pathway might be concomitantly involved in the dysfunction of the cell cycle. On the other hand, the fact that all chiral C2-ceramides tested failed to inhibit the activity of sphingosine kinase acting on the removal of sphingosine by producing sphingosine-1 -phosphate demonstrates that chiral C2- ceramides may increase sphingosine by activating various ceramidases by which natural ceramides are divided into sphingosine and free fatty acids. However, the precise steps involved in this interaction are still unknown.