• Transactions of Materials Processing
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• v.13 no.3
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• pp.230-235
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• 2004

A new design based on the appropriate geometry of molded part and type of runner system under the optimal processing conditions was proposed to minimize the micro weld lines on the sub deco surface molded by two shot molding. Theoretical and experimental studies were conducted to examine the cause of the weld lines during the overmolding process in two shot molding. Various dimensions and geometries of substrate$(1^{st}shot)$ and the wall thickness of overmold$(2^{nd}shot)$ have been proposed to avoid the weld lines which are the most inevitable appearance defects occurred on the sub deco. The each design proposal was analyzed by mold flow analysis after part modeling. The analysis results were compared with molded part from mass production tool. It could be seen that from the analysis that the proper geometry of plastic part and type of runner system considering pressure drop under the optimal processing conditions were the most influential factors to avoid weld lines occured on the sub deco.

• Journal of Welding and Joining
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• v.26 no.4
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• pp.55-60
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• 2008

Structural reliability of electrical panels installed in naval vessels is of critical importance from structural performance viewpoint. The panels may be exposed to vibration and fatigue loadings from internal and external sources and wave loading which cause fatigue cracking. In this study, common methods such as burr grinding and post weld heat treatment (PWHT), for the fatigue strength improvement of weldments are investigated. Burr grinding is carried out using a electric grinder in order to remove surface defects and improve the weld bead profile. And also PWHT is carried out for the purpose of removing residual. The effectiveness of the two post treatment methods is evaluated in terms of fatigue strength improvement of welded structures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.104-105
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• 2008

According to previous report, aged sleeves of old transmission line showed several defaulted installation patterns, which is biased or corrosive-fractured of steel sleeve installed cases. The latter case occupied almost 25 percent of investigated aged sleeves. These defects can cause serious accidents such as rapid increasing of sag or falling out of overhead conductor from sleeves. This paper studies thermal properties and tension for ACSR conductor in case of fractured steel sleeve model. The detailed results were presented in the text.

• Journal of Yeungnam Medical Science
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• v.34 no.1
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• pp.80-83
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• 2017

A number of research papers have reported more frequent occurrence of rheumatic/autoimmune disease among patients with hypogonadism or a chromosomal anomaly with potential X-chromosome defects. A 30-year-old female patient came to the hospital with a main cause of bilateral buttock pain, which began two years ago and worsened seven days ago. Ankylosing spondylitis with invasion of both sacral-iliac joints was observed. On magnetic resonance imaging, although the uterus was observed normally, an ovary was not observed. In a chromosome test, balanced reciprocal X-1 translocation of 46,X,t(X;1)(p10;q10) was diagnosed. Here, we report on the first case involving ankylosing spondylitis accompanied by balanced reciprocal X-1 translocation.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.766-771
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• 2001

Gas-assisted injection molding is an innovative low-pressure injection molding technique that can provide numerous benefits such as reduced part warpage, excellent surface quality without sink marks, low injection pressure, and greater design flexibility. However, the adoption of gas-assisted injection molding may cause unexpected defects if the gas channel design is not conducted properly. The objective of this paper is to broaden the understanding of gas-assisted injection molding by summarizing the design procedures and experimental results of the gas-assisted injection molding of a 17" flat monitor front cover. The gas channels were designed by using Moldflow(MF/GAS) simulations and a 450 ton injection molding machine with a 5 stage pressure control gas kit was used in the experiments.

• Journal of the Korean Institute of Telematics and Electronics
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• v.11 no.1
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• pp.8-14
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• 1974

Investigation of the electrical properties of GaAs after the heat treatment at various As vapor pressure have been carried out. Hall coefficient mesurments were utilized to study the cause of the effect on the electrical properties, of GaAa by the heat treatment. Various defects possibly created by the heat treatment were discussed. Also, p-n GaAs diodes were fabricated and the I-V characteristic curves were presented.

• Korean Journal of Veterinary Research
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• v.47 no.1
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• pp.91-94
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• 2007

tisue disease of dog and cat, resembling Ehlers-Danlos syndrome (EDS) in man. EDS is characterizedby loose, hyperextensible and, fragile skin, it is attributed to mutations in connective tisue gene. Thesemutations cause defects in type I or II collagen synthesis and as a result lack of strength or elasticityto skin, joint, ligament and vessels. EDS-affected animals often experience subcutaneous hematomas thathave long bleeding times. The 4-years old male Yorkshire terrier was evaluated because of subcutaneoushematoma after stifle surgery. Clinical examination revealed a thin and hyperextensible skin and jointlaxity. The degree of skin extensibility index was 23.4%, marked skin stretchy. Clinical diagnosis wasconfirmed by histophathological examination of a skin biopsy revealing reduced packing density ofcollagen fiber of skin.

• International Journal of Railway
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• v.5 no.2
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• pp.71-76
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• 2012

Recently, axle load, operating speed and traffic density on railroads have had a tendency to increase and thereby cause additional pressure applied on used track. These operating conditions frequently result in service failure due to wear caused by wheel-rail contact and fatigue damage under cyclic loading. Among rail defects, the transverse crack, which has been the most dangerous type of fatigue damages, is developed from the subsurface crack near the rail running face and grows perpendicular to the rail surface. Therefore, it is necessary to investigate systematically the growth behavior of transverse crack for rail steel under mixed mode. In this study, the fatigue crack growth behavior of the transverse crack in rail steel was experimentally investigated under mixed-mode variable amplitude loadings.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.1109-1114
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• 2005

The rolling contact fatigue of wheels for high speed trains is a matter of increasing importance. The wheel damages from fatigue crack makes noise up and safety down. RCF-casued accidents cause traffic congestion and economical costs as well as personal injuries. In this study, we examine the rolling contact fatigue of wheels for power car running at 300km/h. Using the results of multi-body dynamic analysis and the proposed procedure of Ekberg, we calculate the fatigue index of surface-initiated fatigue, subsurface-initiated fatigue and fatigue initiated at deep material defects. As a result. the fatigue index shows us whether fatigue will appear and in which form. In addition, we present Shakedown map on surface-initiated fatigue.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.174-175
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• 2022

The blast furnace slag, which is widely used as a cement admixture, has latent hydraulics under the influence of cement hydrate, and fly ash and silica fume mainly cause a pozolane reaction. As a result, the cement structure becomes dense, and it is possible to compensate for defects when concrete is usually made with portland cement alone. When fixing carbon dioxide through reaction with carbon dioxide, the amount of calcium hydroxide in the cement paste is important. The larger the amount of calcium hydroxide, the more active the reaction may occur. It is also an important variable in calculating the depth of neutralization through carbonization. In this study, calcium hydroxide in cement paste using mixed materials was quantified through thermal analysis.