• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.499-504
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• 2002

The microstructural change associated with the hardness profile in friction stir welded, age-hardenable 6005 Al alloy had been evaluated. Frictional heat and plastic flow during friction stir welding created the fine recrystallized grain (Stir Zone, SZ), the elongated and recovered grain (Thermo-Mechanical Affected Zone, TMAZ) in the weld zone. Heat affected zone (HAZ), which could be only identified by hardness test because there is no difference in the grain structure compared with that of the base metal, was formed beside the weld zone. A softened region had been formed near the weld zone during friction stir welding process. The softened region was characterized by the dissolution and coarsening of the strengthening precipitate during the friction stir welding. The sound joints of 6005 Al alloys were successfully formed under a wide range of the friction stir welding conditions.

• Asian Pacific Journal of Cancer Prevention
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• 제15권15호
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• pp.6005-6008
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• 2014

Aim: To compare recurrence rates of large loop excision of the transformation zone (LLETZ) with those of contour-loop excision of the transformation zone (C-LETZ) in the management of cervical intraepithelial neoplasia (CIN). Materials and Methods: The medical records of 177 patients treated consecutively by LLETZ and C-LETZ for CIN at Rajavithi Hospital between 2006 and 2009 were retrospectively reviewed. Results: Of the 87 women in the C-LETZ group, 2 cases (2.30%) had recurrence compared with 13 cases (14.4%) of the 90 women in the LLETZ group, the higher recurrence rate in the latter being statistically significant (p<0.05). Median times of follow up in the C-LETZ and LLETZ groups were 12 months and 14 months respectively (p>0.05). The C-LETZ group showed less intraoperative bleeding compared to the LLETZ group, but the rate of achievement of single specimens and positive margins were similar in the two groups. Conclusions: The present study demonstrated the superiority of C-LETZ over LLETZ in terms of efficacy; C-LLETZ is associated with a lower recurrence rate and also carries a smaller risk of intraoperative bleeding than LLETZ. The rotating technique still has a potential role in treating precancerous lesions of the cervix.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.583-588
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• 1998

Large extrusions of aluminium alloy can be more general and useful as structural material of rolling stocks to reduce weight and labor cost than mild steel and stainless steel. Our company is studying aluminium coach body will be made of 6005A and A5083 alloy. In this paper, at first detailed finite element analysis is carried out to calculate the orthotropic material properties of aluminium extrusions. And then global strength evaluation of coach body is carried out according to UIC 566 OR code.

• 대한기계학회논문집A
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• 제37권7호
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• pp.945-951
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• 2013

본 논문은 도시형 자기부상열차에 사용되는 대차프레임의 피로강도를 평가하는 방법을 제안하였다. 가상의 하중 시나리오로부터 구조해석을 수행하여 응력해석결과를 Goodman 선도상의 피로한계선도와 비교하였으며, UIC 규격에 적용되는 3단계의 피로조건을 적용하여 피로누적손상도(cumulative fatigue damge, D)를 계산하였다. 피로해석결과, Goodman 선도상에서 대차 프레임 사용소재인 A6005 알루미늄 합금 Butt 용접부의 피로한계선도를 초과하지 않았다. 가장 높은 피로손상도는 캐스팅 블록 및 전자석 폴 연결부로서 $1{\times}10^7$ cycles 기준으로 D=0.808로 계산되어 파손기준을 초과하지 않음을 확인하였다. 피로해석과 동일 조건으로 실시된 수직, 좌우, 전후 방향의 피로시험에서 대차 프레임의 어느 위치에서도 균열이 발생되지 않았으며, 이는 피로안전측으로 계산된 해석결과와 부합되는 결과이다.

• 대한기계학회논문집A
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• 제34권2호
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• pp.203-209
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• 2010

본 연구는 철도차량에 적용되는 직물 유리섬유/에폭시 적층 복합재의 피로특성 및 피로수명에 대해 평가하였다. 이때, 피로시험은 0.1의 응력비(R)와 5Hz의 주파수에서 인장-인장 하중 조건이 고려되었으며, 시험편은 카본/에폭시 플라이가 보강된 시험편과 보강되지 않은 시험편 두 가지 타입을 고려하였다. 또한, 직물 유리섬유/에폭시 적층 복합재의 피로수명을 평가하기 위해 철도차량 차체와 언더프레임에 주로 사용되는 알루미늄 6005와 비교하였다. 본 연구를 통하여 3장의 카본/에폭시 플라이가 보강된 직물 유리섬유/에폭시 적층 복합재 시험편이 보강되지 않은 기본 시험편보다 피로강도 및 피로수명이 크게 향상됨을 확인하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.6005-6010
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• 2012

Background: Nasopharyngeal carcinoma (NPC) is endemic in Southern Chinese and Southeast Asian populations. Geographical and ethnic clustering of the cancer is due to genetic, environmental, and lifestyle risk factors. This case-control study aimed to identify or confirm both genetic and non-genetic risk factors for NPC in one of the endemic countries, Malaysia. Materials and Methods: A panel of 768 single-nucleotide polymorphisms (SNPs) previously associated with various cancers and known non-genetic risk factors for NPC were selected and analyzed for their associations with NPC in a case-control study. Results: Statistical analysis identified 40 SNPs associated with NPC risk in our population, including 5 documented previously by genome-wide association studies (GWAS) and other case-control studies; the associations of the remaining 35 SNPs with NPC were novel. In addition, consistent with previous studies, exposure to occupational hazards, overconsumption of salt-cured foods, red meat, as well as low intake of fruits and vegetables were also associated with NPC risk. Conclusions: In short, this study confirmed and/or identified genetic, environmental and dietary risk factors associated with NPC susceptibility in a Southeast Asian population.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.163-168
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• 2001

A FEM-based analytical approach was used to evaluate the fatigue strength of a KHST gangway. A KHST gangway was made of AC4C, 5083-O, 6005A-T6 aluminum alloys. The fatigue strengths of them were obtained from the related code and literatures. The effect of tensile mean stress was taken into account by the modified Goodman diagram, but the effect of compressive mean stress was not considered. There was not any location of a KHST gangway that exceeded the allowable fatigue strengths.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1618-1623
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• 2009

In this paper, we describe the design method of carbody structure with side-buffer. Recently railroad industry has a new interest with stability, fixed time, low environment pollution and mass transportation. Accidents have little on the railroad but railroad industry is trying to minimize carbody damage and passenger injury in case of accidents. So a side-buffer having anti-climber is applied to meet each special needs. Carbody with side-buffer is assembled with aluminum(6005A-T6) parts that are extruded. As the results of the study, it is showed that carbody with side-buffer has sufficient energy absorbtion about crashworthiness.

• 대한기계학회논문집A
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• 제28권6호
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• pp.807-815
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• 2004

In order to evaluate the static stability of hybrid carbody structures of Korean Tilting Train eXpress(TTX) caused by degradation of composites under ground environments, T300/AD6005 graphite/epoxy composite specimens were exposed to accelerated environmental conditions including ultraviolet radiation, temperature and moisture fer 2000 hours. It was found that the stiffness and strength of composites after aging were lower than those of unexposed specimens, and decreased as the aging time increases. The values of the degraded properties were used in the static analysis to check the static stability of hybrid carbody structures caused by environmental degradation of composites. The results shown that the structural stability of hybrid carbody structures was affected by the degradation of composites after exposure to accelerated aging environments.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2053-2058
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• 2008

Extruded aluminium panels have been widely used for railway vehicle structures because of their light specific weight and other merit. In the past, GMAW (Gas Metal Arc Welding) and GTAW (Gas Tungsten Arc Welding) were mainly used to join aluminium panels. But recently friction stir welding (FSW) is widely used. due to its lots of advantage. In this study aluminium A6005-T6 which are used for car body structures was chosen. The influence of main parameters such as : pin rotating speed, welding speed, shoulder diameter, pin length and tilting angle on mechanical properties was examined. Optical microscope observation, micro hardness test and tensile test were carried out. Tensile strength of the stir welded plates is 74% of that of the base material.