• Journal of Microbiology
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• v.35 no.2
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• pp.117-122
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• 1997

Several dominant 4-CPA-degrading bacteria were isoalted from agricultural soils. Most of the isolates were identified as Burkholderia species by fatty acid methyl ester (FAME) analysis, but they were idstinct in chromosomal patterns obtained by PCR amplification of repetitive extragenic palindromic (REP) sequences. These strains were generally restricted in their substrate utilization capabilities. The 4-CPA degradative enzymes were idnducible by 4-CPA and some isolates appeared to mineralize 4-CPA via formation of 4-chlorophenol and 4-chlorocatechol as intermediates during its biodegradation pathway. Plasmid DNAs were not detected from most of the isoaltes and their 4-CPA genes wer on the chromosomal DAN. The 4-CPA degradation patterns in axenic cultures and natural soils varied depending on the strains and soils. The inoculation of 4-CPA degraders much improved the removal of 4-CPA from the 4-CPA treated soils.

• Microbiology and Biotechnology Letters
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• v.29 no.2
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• pp.122-126
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• 2001

Eleven bacterial strains which were able to utilize terephthalic acid as a carbon and an energy source for growth were isolated from the soil of 7 water quality evaluation points in Kyonggi area of Korea. According to the report from the authorities, biochemical oxygen demands of the water at 4 points were reported over 20 ppm but those of 3 points were repOlted less than 2 ppm in 1997. Optimum temperatures of growth and terephthalic acid degrading activity of some isolates were not identical but optimum growth temperature was 30$^{\circ}$C. Most of the isolates utilized one or two of the phthalate isomers as a carbon source for growth and the isolates from the 4 contaminated points showed higher terephthalic acid degrading activity than those from the 3 clean points.

• Geotechnical Engineering
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• v.12 no.3
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• pp.109-126
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• 1996

In this study, the chemical fluid considered is sodium chloride sloutions. The concentrations for the sodium chloride solutions are varied from 0 to 20%. A series of lab oratory triaxial tests are performed on the cylindrical specimens of sand bentonite mixture with different (5, 10, 15%) sodium chloride content solutions. Deformation(elastic modulus, E) and strength (cohesion, c', and angle of friction, f') parameters are obtained from the triaxial tests and they are expressed as functions of conf'ming pressure and sodium chloride solution concentrations. The stress-strain-strength behavior based on the above strength parameters is introduced to the finite element method with a residual flow procedure (RFP). By integrating a slope stability (limit equilibrium) procedure in the finite element method, factors of safety with time are computed.

• The KIPS Transactions:PartD
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• v.11D no.6
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• pp.1287-1294
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• 2004

Recently relationships between reliability measures and the coverage have been developed for evaluation of software reliability. Particularly the mean value function of the coverage-based software reliability growth model is important because of its key role in rep-resenting the software reliability growth. In this paper, we first review the problems of the existing mean value functions with respect to the assumptions on which they are based. Then a new mean value function is proposed. The new mean value function is developed for a general testing environment in which imperfect fault detection and repeated construct execution are allowed. Finally performance of the proposed model is empirically evaluated by applying it to a real data set.

• Journal of Arbitration Studies
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• v.21 no.1
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• pp.259-277
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• 2011

In 2008, North Korea revised its Foreign Economic Arbitration Act. To some extent, the new Act reflected such international standard of arbitration as UNCITRAL Arbitration Rules. In this paper, the said Act will be evaluated, and then cooperation ways of South-North Korea on Inter-Korean Commercial Arbitration will be suggested. In 2007, the Ministry of Unification has designated the Korean Commercial Arbitration Board as Inter-Korean Arbitration Committee and has made efforts to prepare follow-up measures on the two Agreements of Inter-Korean Commercial Arbitration. In 2008 however, the follow-up measures has in fact been suspended. In order to revitalize the Inter-Korean commercial arbitration, some prerequisites must be satisfied. First, Inter-Korean Arbitration Committee for Inter-Korean commercial arbitration should re-open as soon as possible. Second, as North Korea recently shows interest in joining the New York Convention on the Recognition and Enforcement of Foreign Arbitral Awards(now so called New York Convention), Governmental Authority of Rep. of Korea should also actively assist and support their joining in New York Convention. Third, both Korean governments should carry out joint study on raising the efficiency of the arbitration system which they will use. Fourth, comparative study on arbitration systems used in both countries should be conducted. Also, it may is very timely to discuss the issue in international arbitration community such as "North-East Asia International Arbitration Conference" or other similar events. In conclusion, continuous study on prevention of commercial disputes between South-North Korea and ways to resolve disputes when they arise should be conducted.

• Tribology and Lubricants
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• v.22 no.4
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• pp.190-195
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• 2006

A simple and effective analysis method is presented for gaining a complete transient temperatures on the internal and external surfaces of a 40 mm gun tube subjected to a series of rapid firings. Two series of temperature data for both Hs and As were measured by using two rapid response k-type surface thermocouples near the firing origin and the muzzle. With other available temperature data, patterns of temperature variations of the gun tube as a function of time variable were driven through complete evaluations of the data. It is found that overall temperature gradients which increase exponentially toward saturation temperature, actually consist of a series of linear temperature gradients corresponding to the firing sequences. Under the similar firing sequences, patterns of temperature variations fur both the surface temperatures near the chamber and those near the muzzle were found to have linear temperature gradients with different values and the same response frequencies, i.e. they had peaks and lows in temperatures at the same time. The resultant complete temperature data can be used as the fundamental bases for analysis of thermoelastic properties of the materials such as thermal strain and stress, and f3r the prediction of cannon tube life-time through calculation of wear rate.

• Journal of Korean Society of Forest Science
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• v.107 no.3
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• pp.294-304
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• 2018

Since joining the OECD Development Assistance committee in 2010, the Republic of Korea has been continuously striving to promote its international standing. A new era of cooperation is about to open between Korea and Central Asia, with the $25^{th}$ anniversary of the establishment of diplomatic relationship between Korea and Central Asia, and the welcoming the $80^{th}$ anniversary of the Koryoin (Korean) immigration in 2017. Central Asia is also attracting attention with a rapidly growing economy based on the endowed resources. Therefore, Kyrgyzstan and Tajikistan, among others, were investigated in the following statuses: politics, diplomacy, economy, official development assistance and national strategies. In particular, this study suggests the South Korea's Country Partnership Strategy for Forest with the nations by analyzing the forest environment and forest policy regime, and both forest cooperation strategies: 'Ecotourism Projects using a Walnut Forest' in Kyrgyzstan and 'Projects Restoring Forest and Securing Fuel Woods of Degraded Land in Tugai' in Tajikistan.

• Proceedings of the Microbiological Society of Korea Conference
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• 2001.11a
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• pp.16-25
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• 2001

A genomic library of biphenyl-degrading strain Comamonas sp. SMN4 was constructed by using the cosmid vector pWE15 and introduced into Escherichia coli. Of 1,000 recombinant clones tested, two clones that expressed 2,3-dihydroxybiphenyl 1,2-dioxygenase activity were found (named pNB 1 and pNB2). From pNB1 clone, subclone pNA210, demonstrated 2,3-dihydroxybiphenyl 1,2-dioxygenase activity, is isolated. 2,3-Dihydroxybiphenyl 1,2-dioxygenase (23DBDO, BphC) is an extradiol-type dioxygenase that involved in third step of biphenyl degradation pathway. The nucleotide sequence of the Comamonas sp. SMN4 gene bphC, which encodes 23DBDO, was cloned into a plasmid pQE30. The His-tagged 23DBDO produced by a recombinant Escherichia coli, SG 13009 (pREP4)(pNPC), and purified with a Ni-nitrilotriacetic acid resin affinity column using the His-bind Qiagen system. The His-tagged 23DBDO construction was active. SDS-PAGE analysis of the purified active 23DBDO gave a single band of 32 kDa; this is in agreement with the size of the bphC coding region. The 23DBDO exhibited maximum activity at pH 9.0. The CD data for the pHs, showed that this enzyme had a typical a-helical folding structures at neutral pHs ranged from pH 4.5 to pH 9.0. This structure maintained up to pH 10.5. However, this high stable folding strucure was converted to unfolded structure in acidic region (pH 2.5) or in high pH (pH 12.0). The result of CD spectra observed with pH effects on 23DBDO activity, suggested that charge transition by pH change have affected change of conformational structure for 23DBDO catalytic reaction. The $K_m$ for 2,3-dihydroxybiphenyl, 3-metylcatechol, 4-methylcatechol and catechol was 11.7 $\mu$M, 24 $\mu$M, 50 mM and 625 $\mu$M.

• Journal of Biosystems Engineering
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• v.43 no.2
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• pp.83-93
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• 2018

Purpose: This study derived the consumed power and load characteristics of a tillage operation performed in an upland field located in Seomyeon, Chuncheon, Rep. Korea, where potatoes and cabbages were cultivated in two crops. Methods: A plow and rotavator were mounted on a tractor with 23.7 kW of rated power to perform the tillage operation. The work conditions were determined, considering the actual working speed of the tillage operation performed by the local farmers. The power consumption of the rear axle, engine, and power take-off (PTO), PTO torque, and tractive force were measured under each work condition. The consumed power and load characteristics were analyzed using their average values. Results: The rotary-tillage operation consumed more engine power than the plow operation for the same tractor-transmission gear condition. The PTO in the rotary-tillage operation and the rear axle in the plow operation consumed the most power. The power consumption of the engine and the PTO for the rotary-tillage operation tended to increase as the transmission gears of the tractor and the PTO became higher. In contrast, the rear-axle power consumption was insignificant. In addition, the PTO torque tended to rise as the tilling pitch increased. For the plow operation, the drawbar power and the rear axle power accounted for 68-90% of the engine power. The engine and rear axle power, drawbar power, and tractive force tended to rise as the working speed increased. Conclusions: The power consumption and load characteristics differed for the plow and rotary-tillage operations. They may also differ depending on the soil conditions. Therefore, the power consumption and load characteristics in various work environments and regions should be analyzed, and reflected in the design of tractors and working implements. The results derived from this study can be used as a reference for such designs.

• Journal of the Korean institute of surface engineering
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• v.41 no.4
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• pp.147-155
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• 2008

The dental orthodontic wire provides a good combination of strength, corrosion resistance and moderate cost. The purpose of this study was to investigate the effects of TiN and ZrN coating on corrosion resistance and physical property of orthodontic wire using various instruments. Wires(round type and rectangular type) were used, respectively, for experiment. Ion plating was carried out for wire using Ti and Zr coating materials with nitrogen gas. Ion plated surface of each specimen was observed with field emission scanning electron microscopy(FE-SEM), energy dispersive X-ray spectroscopy(EDS), atomic force microscopy(AFM), vickers hardness tester, and electrochemical tester. The surface of TiN and ZrN coated wire was more smooth than that of other kinds of non-coated wire. TiN and ZrN coated surface showed higher hardness than that of non-coated surface. The corrosion potential of the TiN coated wire was comparatively high. The current density of TiN coated wire was smaller than that of non-coated wire in 0.9% NaCl solution. Pit nucleated at scratch of wire. The pitting corrosion resistance $|E_{pit}-E_{rep}|$ increased in the order of ZrN coated(300 mV), TiN coated(120 mV) and non-coated wire(0 mV).