• Journal of the Korean Wood Science and Technology
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• 제47권6호
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• pp.667-673
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• 2019

The performance of a wooden deck made of refractory materials that have difficulties in achieving target penetrations as stipulated in the specification and quality standards for treated wood in Korea, was assessed via a case study in this research. A wooden deck built in Jinju in 2009 was selected for this study because of its fabrication method using pressure and treated refractory materials. The penetration and retention analysis did not satisfy the domestic standard for treated wood. Inspection of the deck in 2019 revealed that the deck had been attacked by decay fungi. Cap rails showed much deeper and wider checking on their surface compared with the top and base rails, resulting in a severe fungal attack. The decking boards exhibited severe fungal decay primarily in the end parts. However, the rails and balusters without checks and posts were virtually free of fungal attack irrespective of the preservative penetration measures. Copper content in the soil 5 cm away from the deck was less than 150 mg/kg, implying that copper movement in the soil was very limited. These results suggest that the inhibition of surface propagation and the protection of end surfaces are essential factors in increasing the longevity of treated wooden decks; further, the results also showed that the deck was within an acceptable range from the point of copper contamination.

• Safety and Health at Work
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• 제7권2호
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• pp.130-137
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• 2016

At a brewery, the base plate-to-shell weld seam of a $90-m^3$ vertical cylindrical steel tank failed catastrophically. The 4 ton tank "took off" like a rocket leaving its contents behind, and landed on a van, crushing it. The top of the tank reached a height of 30 m. The internal overpressure responsible for the failure was an estimated 60 kPa. A rupture disc rated at < 50 kPa provided overpressure protection and thus prevented the tank from being covered by the European Pressure Equipment Directive. This safeguard failed and it was later discovered that the rupture disc had been installed upside down. The organizational root cause of this incident may be a fundamental lack of appreciation of the hazards of large volumes of low-pressure compressed air or gas. A contributing factor may be that the standard piping and instrumentation diagram (P&ID) symbol for a rupture disc may confuse and lead to incorrect installation. Compressed air systems are ubiquitous. The medium is not toxic or flammable. Such systems however, when operated at "slight overpressure" can store a great deal of energy and thus constitute a hazard that ought to be addressed by safety managers.

• Korean Chemical Engineering Research
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• 제51권4호
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• pp.443-454
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• 2013

콜로이드 실리카와 가용성 실리카를 이용하여 나트륨이 첨가되지 않은 다양한 금속이온 첨가 MCM-41 촉매를 제조하였다. 전이금속 이온인 $V^{5+}$, $Co^{2+}$ 및 $Ni^{2+}$이 MCM-41에 첨가되었을 경우 기공벽 내의 실리콘 이온과 등방치환을 하여 실리카 기공벽 내에서 독립된 단일 활성점을 형성하여 우수한 환원 및 활성 내구성을 보였다. 수소 승온 환원법을 이용하여 Co-MCM-41 촉매의 기공 곡률 반경효과에 대해 검토해 본 결과, 적절한 환원 처리와 기공 크기 및 pH 조절에 따라 코발트 금속입자의 크기를 1nm 이하의 범위에서 조절할 수 있었으며, 이 미세 금속 입자들은 표면 금속이온들과의 결합으로 인해 상당한 고온 안정성이 있음을 발견하였다. 완전 환원 후에도 비정형 실리카의 부분 덮힘으로 인해 금속 입자들의 표면 이동 및 뭉침 현상이 현저히 저하되는 것을 볼 수 있었다. 이들 촉매의 반응 예로 금속 입자 크기에 민감한 단일층 탄소 나노튜브의 합성을 Co-MCM-41을 이용하여 실시하였고, 금속 입자의 안정성 시험반응으로 Co 및 Ni-MCM-41을 이용한 CO 메탄화 반응, V-MCM-41을 이용한 메탄올 및 메탄의 부분 산화반응 및 기공곡률 반경이 촉매활성에 미치는 영향 등을 살펴보았다.

• 한국패류학회지
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• 제22권2호
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• pp.175-182
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• 2006

본 연구는 2004년 3월 10일 남해 강진 만에서 채취한 피조개 어미 1,200 마리를 확보하여 수온조절에 의한 인위적인 성성숙을 유도하였으며, 성숙 유도된 어미로부터 잔존율, 비만도, 생식소 조직검사, 적산수온 및 성숙소요일수를 조사하였다. 성 성숙유도된 어미의 잔존율은 $20^{\circ}C$가 94.8％로 가장 높았고, $23^{\circ}C$가 90.3％, 대조구(자연수온구)가 84.8％이었고, $26^{\circ}C$가 18.1％로 온도가 높을수록 잔존율이 낮은 경향이 있었다. 42일 째 생식소 조직의 암컷의 완숙기 출현율은 $23^{\circ}C$ 실험 구에서 67%로 가장 높았고, $20^{\circ}C$ 실험구에서 56%, $26^{\circ}C$에서 22%였으며, 자연수온 실험구에서는 성숙이 매우 늦어 완숙기에 이르지 못하였다. 수컷의 경우, $23^{\circ}C$ 실험구에서 완숙기 출현율이 100%로 가장 높았고, $20^{\circ}C$ 실험구에서 87%, $26^{\circ}C$에서 73%였으며, 자연수온 실험구에서는 50% 순으로 나타났다. 성숙소요일수는 $23^{\circ}C$와 $20^{\circ}C$에서 각각 42일 및 49일, 대조구인 자연수온 $(9.5-14.8^{\circ}C)$에서는 79일이였으며, 성 성숙 유도율은 $20^{\circ}C$와 $23^{\circ}C$에서 각각 55.5% 및 60.5%로 타 실험구와는 유의한 차이를 나타내었다 (p < 0.05). 따라서 $20^{\circ}C$ 실험구 (적산수온: $1,295^{\circ}C$) 가 피조개 어미를 인위적으로 성 성숙을 유도하는데 가장 좋은 것으로 판단된다.

• 수산해양교육연구
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• 제18권2호
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• pp.164-171
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• 2006

본 연구에서는 부산지역의 생선횟집을 중심으로 생선 매운탕의 조리 실태를 조사하여 표준조리법 개발에 기초자료로 활용하고자 하였다. 1. 재료로 사용되는 어류는 조피볼락과 넙치가 공통으로 사용되며, 그 외 어종들을 사용하는 것으로 나타났다. 2. 야채류는 무, 대파, 고추, 양파, 조미 및 향신료는 고춧가루, 마늘, 소금, 후추가 공통으로 사용되고 있는 것으로 나타났으며, 기타 재료들이 부가적으로 사용되는 것으로 나타났다. 3. 생선 매운탕에 사용되는 물은 생수와 어류를 삶은 물을 이용하고 있으며, 기타 야채를 삶은물을 이용하는 곳도 있는 것으로 나타났다. 4. 3-4인분 기준의 생선 매운탕에 사용되는 생선의 양은 조피볼락 1.5-1마리와 넙치 0.5-1 마리에 해당되는 머리와 뼈를 이용하는 것으로 나타났다. 5. 생선 매운탕의 조리방법은 물 끓인 다음 재료를 이용하며, 양념장은 양산품을 바로 이용하는 것으로 나타났으며, 조리기구는 대부분 뚝배기를 이용하는 것으로 나타났다.

• Tribology and Lubricants
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• 제25권6호
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• pp.432-437
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• 2009

The effect of oxidation in SAE 5W30 engine oils on friction and wear characteristics was investigated using reciprocating bench tester and shell 4-ball tester. Commercial engine oils were collected and oxidized using the KS M 2021 method modifying the oxidation time. Kinematic viscosity, total acid number(TAN), FT-IR spectrum and total base number(TBN) also measured to examine the chemical change of oils with oxidation. The results showed that TAN was slightly changed and Kinematic viscosity was suddenly increased during the oxidation stage. however, TBN results keep a constant slope after TBN linearly decreased with oxidation time. Spectroscopy results showed that spectrums were orderly increased at $1710cm^{-1}$ during the oxidation time. Friction test results showed that oxidation of oils formed unstable friction layers causing higher fluctuating friction. however, the wear resistance was independent of oxidized time due to the different friction characteristics by oxidation. We found several factors in relation to lubrication properties with oxidation time. This factors were Viscosity, TBN, change of FT-IR spectrum, friction coefficient using reciprocating bench tester and wear scar.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.229-241
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• 2008

In order to investigate stabilization effect on As-contaminated soils treated by zero-valent iron(ZVI) and industrial by-products, batch tests and column tests were carried out with As-contaminated soils collected from farmland around the abandoned mine site. In batch tests, ZVI and industrial by-products(blast furnace slag, steel refining slag and oyster shell powder) were used as treatment materials to reduce As. Industrial by-products were mixed with As-contaminated soils, in the ratio of 1%, 3%, 5% and 7% on the weight base of dried soil. After incubation, all samples showed the reduction of As concentration and it was expected that ZVI and steel refining slag were effective treatment materials to remove As among treatment materials used in batch test. In column tests, columns were made by acrylic with the dimension of diameter=10cm, height=100cm, thickness=1cm and these columns were filled with untreated soils and treated soils mixed with ZVI and steel refining slag(mixing ratio=3%). Distilled water was discharged into the columns with the velocity of 1 pore-volume/day. During test, pH, EC, Eh and As concentration were measured in the regular term(1 pore-volume). As a result, ZVI and steel refining slag were shown 93%, 62% reduction of As concentration respectively by comparison with untreated soils. Therefore, if ZVI and steel refining slag are used as treatment materials in As-contaminated soils, it is expected that the As concentration in soils is reduced effectively.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2010년도 춘계학술발표대회 초록집
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• pp.57-57
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• 2010

For thin panel welded structure, the various welding distortions were found due to the low resistance against welding deformation. Especially, buckling distortion induced in the thin panel welded structure produce severe problems related to cost in production stage and safety in service life. So, many researches including mechanical and thermal tensioning method for preventing the occurrence of buckling distortion in the production stage have been performed. The purpose of this study is to identify the behavior of longitudinal residual stress at the SA butt weldment with thin plate of 6mm thickness under tension load by 3 dimensional FEA. For it, mesh design for 3D FEA was constructed with 20 nodes brick element for butt weldment and 8 nodes shell element for base metal. According to FEA results, the longitudinal compressive strain inducing tensile residual stress at the butt weldment decreased. It was because the compressive thermal strain in way of weldment was reduced by tension load. The control effect of residual stress increased with an increase in tension load. So, if the amount of tension load applied to the weldment exceeds 1.5 times of longitudinal shrinkage force, the amount of longitudinal residual stress decreased below the critical value inducing the buckling distortion at the SA butt weldment. Its validity was verified by experiment.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제14권4호
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• pp.275-282
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• 1992

Maxillofacial war injures is specific representative of severe hard and soft tissue defect. This type of injuries were different from the trauma because it may be fatal. The purpose of this study was to evaluate the injury type base on the retrograde medical record in the 104 patients from Feb. 1991 to Aug. 1992 in Korea Veterans Hospital. The obtained results were as follows. 1. Among 104 cases, 51 cases(49.0%) were classified as mandibular defects only, and 53 cases (51.0%) were classified as maxillary with mandibular defect (combined). 2. The etiologic factors of injury were gunshot, artillery and grenade or shell: 33 cases, 14cases, and 10 cases respectively in Korea War, 19 cases, 5 cases, and 8 cases respectively in Vietnam War. 3. In 57 cases of mandibular partial defect, the angle area showed the highest frequencies, 18 cases(31.6%). 4. In 42 cases of mandibular segmental defect, the area between the 1st molar and the ascending ramus showed the highest frequencies. 17 cases(40.4%), and almost all cases were unilateral defect (40 cases, 95.0%) 5. Reconstruction method performed for segmental mandibular defect were wire or plate(15 cases, 35.7%) and soft tissue closure only(12 cases, 28.7%), respectively.

• 정보관리연구
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• 제27권1호
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• pp.1-39
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• 1996

본 연구는 EconRef이라는 통합 OPAC의 구현에 관한 것으로서, 이 모델은 참고사서의 효율적인 업무처리를 가능하게 해주고, 이용자에게 조직적이고 신속한 정보서비스를 제공하는 것이다. 통합 OPAC은 REGIS와 The Book House와 같은 실제의 시스템을 기초로 하여 KPWin++를 이용하여 구현하였다. KPWin++는 전문가시스템 쉘로서 하이퍼텍스트와 전문가시스템이 결합되어 있다. 이 통합 OPAC 시스템은 6개의 모듈로 참고봉사 전문가시스템 ; 문헌정보원, 전문가정보원, 통계정보원 ; OPAC ; 외부데이터베이스 ; 이용자안내 등으로 구성되었다. 시스템의 평가는 EconRef 시스템과 초급사서 및 고급사서를 비교하였고, 하이퍼텍스트와 전문가시스템이 결합된 OPAC인 REGIS 시스템과 비교하였다. 비교결과 EconRef 시스템은 고급사서와 유사한 반면 초급사서 보다는 우수한 것으로 나타났다.