• The korean journal of orthodontics
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• v.22 no.2 s.37
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• pp.427-447
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• 1992

The purpose of this study was to evaluate the effect of the lateral displacement on the mandibular condylar growth in the rabbit. The experimental animals were twenty White NewZealand rabbits of 4-week old. Ten of them was used as control group, and experimental animal was composed of remaining ten. Laterodeviation appliance was made of cast base metal and appliance was cemented with resin in permanent fashion. Experimental group were sacrificed at 1, 2, 4, 6, 8 weeks form beginning of the experiment. Both of temporomandibular joint were prepared for histologic study. The conclusions are: 1. In control group, there was slight increase of proliferative zone and hypertrophic zone at 2-week control animal and slight reduction at 4-week. 6-week and 8-week control animal were similiar to 1-week control animal. 2. In right mandibular condyle of experimental group, 2-week experimental animal showed marked increase of proliferative zone and hypertrophic zone at posterior surface of condylar head. In 8-week experimental animal marked increase at anterior surface of anticular surface is observed. 3. In left mandibular condyle of experimental group, proliferative zone and hypertrophic zone were reduced at 1-week experimental animal and slight increase at 2-week. Proliferative zone and hypertrophic zone were reduced at 4-week experimental animal and were slightly increased at 6 week. 4. After 8 weeks, right and left condyle were not different in experimental group. The condylar cartilage was stabilized 8 weeks after the experiment. No marked traumatic change was seen, but minute focal bleeding was seen at articular cavity in 1-week, 2-week and 4-week experimental animal. 6-week and 8-week experimental animal did not show bleeding tendency in articular cavity.

• Carbon letters
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• v.26
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• pp.18-24
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• 2018

Pollution of chloride ion-reinforced concrete can trigger active corrosion processes that reduce the useful life of structures. Multifunctional materials used as a counter-electrode by electrochemical techniques have been used to rehabilitate contaminated concrete. Cement-based pastes added to carbonaceous material, fibers or dust, have been used as an anode in the non-destructive Electrochemical Chloride Extraction (ECE) technique. We studied the performance of the addition of Carbon Fiber (CF) in a cement-graphite powder base paste used as an anode in ECE of concretes contaminated with chlorides from the preparation of the mixture. The experimental parameters were: 2.3% of free chlorides, 21 days of ECE application, a Carbon Fiber Volume Fraction (CFVF) of 0.1, 0.3, 0.6, 0.9%, a lithium borate alkaline electrolyte, a current density of $4.0A/m^2$ and a cement/graphite ratio of 1.0 for the paste. The efficiency of the ECE in the traditional technique using metal mesh as an anode was 77.6% and for CFVF of 0.9% it was 90.4%, with a tendency to increase to higher percentages of the CFVF in the conductive cement-graphite paste, keeping the pH stable and achieving a homogeneous ECE in the mass of the concrete contaminated with chlorides.

• Journal of the Korean Society of Costume
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• v.52 no.5
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• pp.173-186
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• 2002

Street Style, occurred in British and America, has been expressed the character of the new generation by repeating developments and changes. Nowadays, pop music reflects the phase of society. and simultaneously it has influence on from culture to society. Rock Music was rooted in Country 8l western of America. Upon Country & Western, Afro-Americans Rhythm & Blues was added, and that was the birth of Rockabilly. Rockabilly developed to Rock'n 'roll and it started to change to various forms of Rock since 1950s. As the commercial impact and the breakthrough of teenagers emotion, the rock culture comprised the base of the youth culture. However. it formed the anti-establishment culture against the established value, accepting working class subculture. The teenager culture was affected by the Rock culture, also found relief in the opulence provided by the established generation, imitating it as it was. Simultaneously, it had a contrary aspect as anti-establishment form under the banner of revolt against languor in richness. The youth culture created street style that was escaped from high fashion, every time Rock music had changes. Since Street style was based on resistance of established culture and it fully refused vogue, it was indifferent from high fashion. The results of this study were as following. First, every time Rock music had changes, the new youth culture was concomitant with, the youth culture created street style. Secondly, rockahibilly style was characterized as diamond shaped design, embroidery, extra wide shirt collar, vivid contrast color . Rockers style was represented as metal studs, beads, denim, leather jacket, boots. Fusion of hippies style and Psychedelic, long hair, beads. worn denim were elements of headbangers style. Punks style was characterized as ripped T-shirt. rooster hair, over decorated jacket, short skirt. net or plastic T-shirt. Lastly, the firm relation between popular art and fashion was proved by examining the history of Rock Music and Street Style.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.8
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• pp.1069-1075
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• 2012

Laser is high density heat source, so it can make high speed welding with minimum heat input possible. Especially the high power fiber laser is recently commercialized and has high beam quality and the smallest system size compared with conventional laser due to it's unique oscillating mechanism. Because of these advantages it's thought that the most suitable heat source for LNG cargo tank welding precess which has to be conducted inside of ships. In this study fiber laser was used for welding of stainless steel for LNG carrier to applicate laser welding technique for shipbuilding industry. 1.2mmt STS304L of austenite stainless steel which apply to cargo tank was used for fiber laser welding. Butt and lap welding was conducted changing laser power, welding speed, then penetration characteristic was analyzed and optimal parameters for each materials. Consequently, we found that same or better mechanical properties were obtained in weld compared to base metal.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.589-595
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• 2013

This paper was to study the effect to Yongrak phenomenon of I groove submerged arc welding depending on the plasma cutting surface characteristics, and how to reduce the causes and characteristics Yongrak phenomenon. Shipbuilding and marine structures is designed to use the thick plates and welded by high current to obtain deep penetration. Yongrak phenomenon has been occurred frequently depending on the quality of cutting surface and it makes degrade of the welding quality and modification of the welding. As a result, it was confirmed that I Groove plasma cutting characteristics get bevel form of 2 to 4 degrees to one side direction from the vertical position with Yongrak phenomenon. This is the main reason of Yongrak phenomenon in butt joint welding and 4 degree reverse bevel on the upper surface of base metal by submerged arc welding brought the effect of significant reduction of Yongrak phenomenon.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.67-72
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• 2010

The fracture toughness for the LBB analysis of piping is generally determined by the J-integral according to ASTM E1820. However, since this evaluates a base metal, the fracture toughness for narrow gap welding can be differently than the real value. This study evaluated the plastic  factor of the narrow gap welding part of a nuclear piping with SA508 Cl.1a and SA312 TP316. Also, it performed the fracture toughness test for the narrow gap welding part and applied the new plastic $\eta$ factor equation by Huh, et al. and then compared the results with those according with the ASTM standard.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.663-670
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• 2005

DIN CK35 (JIS S35CK) steels have been used as a material in fuel pump blocks for marine engines. Failures in the inner surface of a drilling hole, due to the initiation of fatigue cracks have been frequently reported. However, the mechanism initiating these cracks and growths has not been clearly diagnosed yet. This study was conducted using a scraped fuel pump block, containing an initiated fatigue crack in the inner surface of a drilling hole. Initially, the cracks and fractured surfaces inside the block were investigated using an optical microscope and a SEM (Scanning Electron Microscope). In addition, microstructure observation, fatigue life test and fatigue crack growth test were performed using a specimen, which was taken from the same block. Results from these tests are summarized as follows; (1) The early crack in the block was supposed to occur inside the inner surface of the drilling hole. (2) The fatigue endurance of this material was about 330 Mpa. (3) The early crack was generated in the cavitations created by the breakdown of a big inclusion, or separation between the big inclusion and the base metal, in which the fundamental ingredients of the inclusion were C, 5, and Mn. (4) In order to prevent these types of failures, the suppression of inclusions inflow by improving the casting process, formation of fine inclusions by applying a heat treatment process, and coating of the surface of the drilling hole were required.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.1
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• pp.79-88
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• 2002

13%Cr martensitic stainless steel has been used mainly with a material for fish pre-processing machinery. However, it has not very nice cutting section because of little of the carbon content. Therefore, SUS420J2 steel that contents 0.3%C with high-strength in spite of the rust is used with a material for fish pre-processing machinery. However, studies on the corrosion characteristics of SUS420J2 steel are relatively rare. Especially, the corrosion phenomenon may cause serious degradation because the fish pre-processing machinery is exposed always to seawater environment. In this paper, the immersion corrosion test was carried out at seawater environment (pH=7.52) on SUS420J2 steel specimens that have various post-treatment conditions and its corrosion characteristics were evaluated. From test results, the specimens such as base metal, vacuum heat treatment, electrolytic polishing and tempering after quenching tend somewhat sensitive from the corrosion. In the case of vacuum heat treatment specimen of continuous immersion during 360 days, the weight loss ratio was high about seven times when compared with the different specimens. On the contrary, SUS420J2 steel specimen that has the heat treatment of tempering after quenching and the electrolytic polishing was less sensitive from the corrosion, and the weight loss ratio was very low.

• Journal of Korean Society of Steel Construction
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• v.17 no.6 s.79
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• pp.689-697
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• 2005

Recent test results on reduced beam section (RBS) steel moment connections show that specimens with a bolted web connection tend to perform poorly due to premature brittle fracture of the beam flange at the weld access hole. A review of previous test results indicates that the higher incidence of base metal fracture in bolted-web specimens is related, at least in part, to the web bolt slippage and the high stress concentration at the weld access hole with the lowest material toughness. The practice of providing web bolts uniformly along the beam depth based on the classical beam theory is questioned in this paper. A new seismic design procedure, which is more consistent with the actual load path identified from the analytical and experimental studies, is proposed together with improved connection details. A test specimen designed following the proposed procedure exhibited a cyclic connection rotation capacity sufficient for special moment frames without fracture.

• Journal of Korean Society of Steel Construction
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• v.24 no.4
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• pp.479-490
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• 2012

Flexural tests on full-scale H-shaped beams, built up from high-strength steels (HSB800 and HSA800) with a nominal tensile strength of 800 MPa, was carried out to study the effect of flange slenderness of high-strength steel on flexural strength and rotation capacity. The primary objective was to investigate the appropriateness of extrapolating current stability criteria (originally developed for ordinary steel) to high-strength steel. The performance of high-strength steel specimens was very satisfactory from the strength, but not from the rotation capacity, perspective. The inferior rotation capacity of high-strength steel beams was shown to be directly attributable to the absence of a distinct yield plateau and the high yield ratio of the material. Residual stress measurements reconfirmed that the magnitude of the residual stress is almost independent of the yield stress of the base metal.