• Journal of the Korean Wood Science and Technology
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• 제30권4호
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• pp.58-65
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• 2002

본 연구는 수액치환법을 이용한 침엽수 간벌소경재나 미(저)이용 활엽수재의 산지 보존처리 기술을 개발하기 위하여 수행되었다. 본 논문에서는 증산법과 원구법을 이용한 3종 침엽수와 3종 활엽수의 방부제, 난연제, 치수 안정제 처리 가능성을 조사하여 보고한다. 수종과 처리약제의 조합에 관계없이 원구법이 증산법에 비하여 약제의 목재내 침투가 양호할 뿐만 아니라 약제의 침투가 균일한 관계로 수분 이동경로를 이용한 처리재 생산은 원구법의 사용이 바람직하였다. 원구법 처리는 수관부를 절단한 후 실시하기 때문에 증산법에 비하여 처리가 용이할 뿐만 아니라 벌채 및 조재 후 산지의 일정 장소로 운재 후 처리를 실시하기 때문에 증산법과 비교할 때 집약적 처리로 단위시간당 처리재 생산량이 높고 산지 환경오염 문제도 예방할 수 있는 장점이 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.793-799
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• 2004

In track a third weakness point is joint part, turnout part, curve part. One of them joint part of rail have been known to the most weak point by loosen of joint bar and fish bolt due to impulse and vibration by wheel contact at times. In addition happen to deformation and failure at end of rail, failure and miniature of ballast gravel. Finally impact between wheel and rail become origin cause of a welded rail, noise and vibration. riding condition deterioration, besides track failure. In the present domestic, Thermite and Gas pressure weldings have been used to continuous welded rail(CWR), however stiffness and confidence in quality is lower than Flash butt welding method. FRW have the excellent capacity, however have a shortcoming large scale of machine and power equipment. Therefore we will introduce Mobile Flash Butt Welder can weld in track.

• Journal of Welding and Joining
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• 제23권4호
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• pp.73-80
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• 2005

Arc blow being occurred by Electro-Magnetic force(EMF) during the electric arc welding prevents the formation of a sound weldment. In this study, the effects of arc position, groove size, tack weld and base plate on the EMF in a butt-joint welding of mild steel plate are analyzed by a computer simulation based on the finite element method. The EMF can be numerically identified to be caused by a difference of the magnetic flux-density between ahead of and behind the arc in case that the workpiece locates asymmetrically around the uc. When there exists an air gap of groove ahead of the arc in the welding direction, the similar magnetic force has been producted regardless of the arc position and the gap size. The tack weld alleviates the magnetic force to about one fourth at the finish end of the workpiece. The magnetic force can be also significantly reduced with the base plate to about one fifth at the start end of the workpiece containing a tack weld.

• Journal of the Korean Wood Science and Technology
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• 제49권2호
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• pp.107-121
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• 2021

본 연구에서는 층재 수종과 길이방향의 합판 접합방식과 접합부의 접착제 도포 여부에 따른 휨 성능 및 파괴 양상 분석을 통하여 합판을 코어로 사용한 CLT에 적합한 합판의 접합 방식을 최적화 하고자 하였다. 더글라스 퍼 층재의 경우 길이방향 접합에 의해 휨탄성계수 약 11.5% 감소, 휨강도는 접착제 도포 및 접합방식에 따라 증가 또는 감소하였다. 접착제 미도포 butt joint, 접착제 도포 half lap joint, butt joint 조건이 최적조건으로 도출 되었다. 낙엽송 층재의 경우 길이방향 접합에 의해 휨강도는 약 15%, 휨탄성계수는 약 40% 감소하였으며 접합방식에 따른 차이를 나타내지 않았다. half lab joint와 tongue & groove joint 사용 시 합판 층의 접합부에서 휨에 파괴를 1차적으로 방지해줌으로써 중층의 층재로 전달되는 하중을 감소시켜 주는 것으로 판단된다. 본 연구 결과를 통해 Ply-lam CLT 제조과정에서 낙엽송 층재를 사용하는 경우 접합방법에 따른 차이를 나타내지 않았으며 더글라스퍼 층재를 사용할 경우 butt joint와 half lap 접합 방식이 적합할 것으로 판단된다.

• Journal of the Korean Wood Science and Technology
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• 제28권4호
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• pp.61-71
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• 2000

The effect of the treatment with CCFZ, FR-4, and PEG400 from butt end on the dimensional stability and bending properties was examined. Three softwood species such as red pine, Korean white pine and Japanese larch and three hardwood species such as poplar, alder and oak were investigated in this research. Shrinkage of red pine, Korean white pine, poplar, and alder treated with PEG400 decreased. However, there was no significant decrease of shrinkage in Japanese larch and oak. The decrease of shrinkage when moisture content changed from about 20% to 10% was larger than that at any other phase. In regard to the effect of treatment on bending properties, bending MOE and MOR of all specimens treated with PEG400 decreased significantly. Especially in the case of red pine, poplar, and alder treated with PEG400, bending MOR reduced 9%, 14%, and 12%, respectively. Reductions of MOR of the hardwood was also much larger than that of the softwood. However, in all species, treatment with CCFZ and FR-4 did not affect the change of bending MOE and MOR significantly. Comparing the large specimen which also included heartwood with the small specimen which included only treated sapwood, there was a difference in the change of bending MOE and MOR between them. The large specimens of Korean white pine, alder and Poplar, which had a relatively low proportion of sapwood(18~22%), showed the decrease of MOR by 11~13% more than that of small specimens, while red pine, Japanese larch and oak, which had a relatively high proportion of sapwood(35~40%), showed little decrease. It means that bending MOE and MOR of structural wood treated from butt end should be considered in terms of sapwood proportion as well as effect of treated chemicals.

• 한국산림과학회지
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• 제26권1호
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• pp.13-18
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• 1975

본시험(本試驗)은 죽간재적(竹稈材積)에 영향(影響)하는 형질(形質)을 정확(正確)하게 파악(把握)하기 위(爲)하여 계획(計劃)되었다. 그리고 왕대의 수개형질상호간(數個形質相互間)의 표현형상관(表現型相關), 유전상관(遺傳相關) 및 환경상관(環境相關)을 구명(究明)하고져 공분산분석(共分散分析) 되었으며 Dewey and Lu의 편회귀분석법(偏回歸分析法)으로 각형질(各形質)이 죽간재적(竹稈材積)에 미치는 효과(効果) 즉(即) 경로계수(經路係數)를 산출(算出)하였다. 조사형질(調査形質)은 흉고직경(胸高直徑), 죽간고(竹稈高), 지상고(枝上高), 지하경(地下莖), 절수(節數), 근원직경(根元直徑) 및 죽간재적(竹稈材積)이며 각(各) 형질(形質)의 평균치(平均値), 표준오차(標準誤差), 분산(分散) 및 표준편차(標準偏差)는 제(第)1표(表)와 같고 7개형간(個形間)의 표현형(表現型), 유전(遺傳) 및 환경상관(環境相關)을 분산분석(分散分析)한 결과(結果)는 제(第)2표(表)와 같이 계통간(系統間)에는 고도(高度)의 유의성(有意性)이 인정(認定)되었으나 몇몇 반복간(反覆間)에는 유의성(有意性)이 인정(認定)되지 않았다. 각(各) 형질(形質)의 유전력(遺傳力)을 추정(推定)한바 흉고직경(胸高直徑)과 근원직경(根元直徑)은 유전력(遺傳力)이 높고 기타형질(其他形質)의 유전력(遺傳力)은 제(第)4표(表)에서와 같이 보다 낮으며 환경상관(環境相關)은 표현형상관(表現型相關), 유전상관(遺傳相關)보다 전체적(全體的)으로 낮다. 그리고 죽간재적(竹稈材積)에 대(對)하여 근원직경(根元直徑)과 흉고직경(胸高直徑)은 높은 상관관계(相關關係)를 나타내었다. 형질별(形質別) 상관관계(相關關係), 경로계수(經路係數) 및 죽간재적(竹稈材積)에 미치는 직접(直接), 간접효과(間接効果)는 도표(圖表) 1과 제(第)5표(表)에서 볼 수 있으며 결과적(結果的)으로 본시험(本試驗)에서는 죽간재적수량(竹稈材積收量)은 근원직경(根元直徑)과 흉고직경(胸高直徑)에 의(依)하여 좌우(左右)될 수 있다는 것을 알았다.

• Advances in nano research
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• 제3권3호
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• pp.169-176
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• 2015

Iron nanoparticles were made by using the modified coprecipitation technique. Usually the characteristics of synthesised particles depend upon the process parameters such as the ratio of the iron ions, the pH of the solution, the molar concentration of base used, type of reactants and temperature. A modified coprecipitation method was adopted in this study. A magnetic stirrer was used for mixing and the morphology and nature of particles were observed after synthesis. Nanoparticles were characterised through XRD. Obtained nanoparticles showed the formation of magnetite and maghemite under citric acid and oxalic acid as stabilisers respectively. The size of nanoparticle was greatly affected by the use of different types of stabilisers. Results show that citric acid greatly reduced the obtained particle size. Particle size as small as 13 nm was obtained in this study. The effects of different kinds of nucleating agents were also observed and two different types of nucleating agents were used i.e. potassium hydroxide (KOH) and copper chloride ($CuCl_2$). Results show that the use of nucleating agent in general pushes the growth phase of nanoparticles towards the end of coprecipitation reaction. The particles obtained after addition of nucleating agent were greater in size than particles obtained by not utilising any nucleating agent. These particles have found widespread use in medical sciences, energy conservation and electronic sensing technology.

• 건축역사연구
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• 제18권1호
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• pp.7-29
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• 2009

In understranding the essence of the Korea traditional Architecture, it is important to consider the jointing methods of architectural members, architectural technologies, etc. Especially the purpose of this study is understanding on the Jointing Method of Wooden Members in the period of Unified Silla Architecture. It's conclusion is summarized as follows. 1. A section of column has very close to do with the foundation stone. The structures of foundation stone and column are generally concluded by butt joint, arrow-head joint, housed joint by Grang-e method. Judu is structured by arrow-head joint And, in general, beam is structured by Sagaematchum Chumcha and sagaljudu of Don direction. At the head of Pyungju and the body of Goju, Changbang is structed by Jangbumachum with arrow-head joint or by jumukchang-machum. Also, it is surmised that Gyisoseum and Anssolim methods had been applied to columns from former ages. The example can be found at Bagjae Mireuksaji stone pagoda. Bagjae Mireuksaji stone pagoda taking wooden-pagoda form adopts Gyisoseum and Anssolim methods. We can also find such a sort of methods from other stone constructions like Budo, etc. 2. Injahwaban is structured by short Changbumachum with arrowed-head joint at upper members, and by Anjangmachum at the lower part. This sort of Gongpo style can be seen in the mural painting of tomb of Koguryo and in Buplyungsa, Buplyunsa, Bupkisa-located in Japan, which are influenced by Bakjae or Unified Silla. It is considered that at the end of the late United Silla, Injawhaban had been replaced with Chumcha and Soro on the Pyungbang under influence of Dapo style from China.

• Journal of Welding and Joining
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• 제33권3호
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• pp.62-67
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• 2015

A very large shell-structure built in shipyards like ship hulls or offshore structures are joined by welding through full process. As the welding contains a high thermal cycle at a local area, the welded structures should be distorted unavoidably. Because a distorted ship block should be revised to the designed value before the next stage, the ability to predict and to control the weld distortion is an accuracy level of the yard itself. Despite the ship block size, several present thermal distortion methodologies can deal those sizes, but it is a different story to deal full ship size model. Even a fully constructed ship hull not remaining any welding can have an accuracy issue like outfitting installation problems. Any present thermal distortion methodology cannot accept this size for its recommended element size and the number. The ordinary welding breadth at erection stage is about 20~40 mm. It can hardly be a good choice to make finite element model of these sizes considering human effort and computational environment. The finite element model for structure analysis of a ship hull is prepared at front-end engineering design stage which is the first process of the project. The element size of the model is as fine as the longitudinal space, and it is not proper to obtain a weld distortion at the erection stage. In this study, a methodology is suggested that a weldment can be shrunk at original place instead of using structural finite element model. We cut the original shell elements at erection weld-line and put truss elements between the edges of cut elements for weld shrinkage. Additional truss elements are used to facsimile transverse weld shrinkage which cannot be from the weld-line truss element shrink. They attach to weld-line truss element like twigs from barks. The capacity of developed elements is verified through an accuracy check of erection process of a container vessel at the apt. hull. It can be a useful tool for verifying a centering accuracy after renew and for block-separating planning considering accuracy.