• Nuclear Engineering and Technology
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• 제42권3호
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• pp.319-328
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• 2010

Bonded tendons have been used in reactor buildings at some operating nuclear power plants in Korea. Assessing prestress force on these bonded tendons has become an important pending problem in efforts to assure continued operation beyond their design life. The System Identification (SI) technique was thus developed to improve upon the existing indirect assessment technique for bonded tendons. As a first step, this study analyzed the sensitivity of the key parameters to prestress force, and then determined the optimal parameters for the SI technique. A total of six scaled post-tensioned concrete beams with bonded tendons were manufactured. In order to investigate the correlation of the natural frequency and the displacement to prestress force, an impact test, a Single Input Multiple Output (SIMO) sine sweep test, and a bending test using an optical fiber sensor and compact displacement transducer were carried out. These tests found that both the natural frequency and the displacement show a good correlation with prestress force and that both parameters are available for the SI technique to predict prestress force. However, displacements by the optical fiber sensor and compact displacement transducer were shown to be more sensitive than the natural frequency to prestress force. Such displacements are more useful than the natural frequency as an input parameter for the SI technique.

• Journal of Welding and Joining
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• 제23권6호
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• pp.67-71
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• 2005

This paper is concerned with a study on fracture strength of composites in an adhesive single lap joint. The tests were carried out on joint specimens made with hybrid stacked composites consisting of the polyester and bamboo natural fiber layer. The main objective of this work was to evaluate the fracture properties adjacent to adhesive bonded joint of natural fiber reinforced composite specimens. From the results, natural fiber reinforced composites have lower tensile strength than the original polyester. But tensile-shear strength of natural fiber reinforced composites with bamboo layer far from adhesive bond is as high as that of the original polyester adhesive bonded joints. Spew filet at the end of the overlap reduced the stress concentration at the bonded area. Spew fillet and position of bamboo natural fiber layer have a peat effect on the tensile-shear strength of natural fiber reinforced composites including adhesive bonded joints.

• 무역상무연구
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• 제67권
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• pp.97-118
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• 2015

This study reviews the judgements by the Korean Supreme Court on the time of delivery of goods, as it depends on which bonded place the goods are kept for the purpose of the customs clearance. Thereafter, this study analyzes the Ocean Carrier's liability, when the cargoes are mis-delivered without the presentation of bill of lading in relation to the specific bonded place such as an independent bonded warehouse or a self-use bonded warehouse. Furthermore, considering that voyage charter is a kind of marine transport, this study also reviews whether or not the Court's judgements, which has been developed in respect of the carriage of affreightment, could be applied to voyage charter in respect of the time of delivery goods and the Ocean Carrier's liability for mis-delivery. Lastly, in the case that the substantial importer takes the goods from the independent bonded warehouse without the presentation of bill of lading after the customs clearance, it is noted that the Court has made the Ocean Carrier liable for the mis-delivery through the application of theory of double deposit contract. The position of the Court would be understandable in terms of the protection for the bona-fide holder of bill of lading, but this study reviews the limitation of liability as the device for the protection of the Ocean Carrier, considering the situation where the Ocean Carrier is somewhat unreasonably sacrificed under the bonded system provided for the convenience of substantial importer.

• 한국결정학회지
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• 제15권1호
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• pp.29-34
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• 2004

Cholesteryl hemisuccinate($C_{31}H_{50}O_4$)의 구조를 X-선 회절법으로 연구하였다. 이 화합물의 결정의 공간군은 $P2_12_12_1$이며, 단위세포내에 결정학적으로 서로 독립적인 4개의 분자들로 구성되어있다. 이들 분자들은 두 개의 분자들이 수소결합으로 결합된 hydrogen-bonded dimer 두쌍을 만들며, 결정내에서 단단히 결합되어있다. 두쌍의 hydrogen bonded dimer들은 각 각 b = 0.0과 b = 0.25 부근에서 head to head 배열을 이루며, c-축에 나란하게 배열되어 있다. 수소결합의 영향으로 결정의 녹는점이 $180^{\circ}C$으로 높다

• 소성∙가공
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• 제14권3호
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• pp.257-262
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• 2005

In order to improve the quality of the sheared surface in cutting of inner structure bonded sheet metal the cut-off operation is mainly investigated, which is the typical shearing process in sheet metal forming technology. The sandwich sheet metals considered have inner structure which is constructed in the form of crimped expanded metal and woven metal. The inner structure is bonded between solid sheet by resistance welding or adhesive bonding. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results we found that the influence of sheared position can be observed and explained clearly and this result can be utilized to get the better sheared surface.

• Macromolecular Research
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• 제13권5호
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• pp.441-445
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• 2005

Thermoplastic polyurethane elastomer (TPUe) fiber mats were successfully fabricated by electrospinning method. The TPUe fiber mats were subjected to a series of cycling tensile tests to determine the mechanical behavior. The electrospun TPUe fiber mats showed non-linear elastic and inelastic characteristics which may be due to slippage of crossed fiber (non-bonded or physical bonded structure) and breakage of the electro spun fibers at junctions (point-bonded or chemical bonding structure). The scanning electron microscopy (SEM) images demonstrated that the point-bonded structures of fiber mats played an important role in the load-bearing component as determined in loading-unloading component tests, which can be considered to have a force of restitution.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제3회 금형가공 심포지엄
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• pp.33-38
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• 2004

In order to improve the quality of the sheared surface in cutting of inner structure bonded sheet metal the cut-off operation is mainly investigated, which is the typical shearing process in sheet metal forming technology. The sandwich sheet metals considered have inner structure which is constructed in the form of crimped expanded metal and woven metal. The inner structure is bonded between solid sheet by resistance welding or adhesive bonding. The shearing process is visualized by the computer vision system installed in front of the cut-off die and the sheared surface is measured and quantitatively compared with the help of the optical microscope after cut-off operation. From test results we found that the influence of sheared position can be observed and explained clearly and this result can be utilized to get the better sheared surface.

• 한국추진공학회지
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• 제21권4호
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• pp.96-106
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• 2017

압축형 복합화약에서는 압축 시 화약입자들의 재배열 및 변형으로 인하여 화약입자들의 압착화가 이루어지게 된다. 만약 깨지기 쉬운 화약입자들이 입자들의 최대 무질서밀집충진율보다 높아질 때까지 압축되면 큰 입자들은 깨짐으로써 빈 공간을 채울 수 밖에 없다. 본 연구에서는 다성분 입자계를 적용하여 압축 시 화약입자들의 손상을 막음으로써 둔감하면서도 고도로 충진된 압축형 복합화약을 얻고자 하였으며 실험결과, 2성분 입자계보다 3성분 입자계에서 더 고밀도이면서도 둔감한 ?감도를 갖는 압축형 복합화약을 얻을 수 있었다.

• 대한치과보철학회지
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• 제38권3호
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• pp.375-381
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• 2000

The conventional approach for replacing missing maxillary lateral incisors dictates the placement of either a conventional porcelain-fused-to-metal (PFM)bridge, resin-bonded fixed partial denture, or single implant prosthesis. However, several appearance-related disadvantages have been reported in the use of a prosthesis which incorporates a metal substructure. To address these limitations, metal -free restorative alternatives have been recently developed to expand the clinical options when fabrication of these prostheses is indicated. This clinical report describes the treatment of patients with a missing maxillary lateral incisor where the dentition was non-invasively restored with resin-bonded fixed partial denture(RBFPD) using In-Ceram and Targis-Vectris system.

• Restorative Dentistry and Endodontics
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• 제21권2호
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• pp.569-584
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• 1996

The purpose of this study was to elucidate the effect of benzalkonium chloride on tensile bond strength of BPDM/HEMA dentin bonding. One hundred sixty dentin specimens from freshly extracted bovine mandibular incisors were used, and 0, 0.02, 0.1 or 0.5% benzalkonium chloride solution was applied to the dentin specimen with/after phosphoric acid. 32% phosphoric acid was used when the specimens were bonded with One-Step$^{TM}$, a BPDM/HEMA system and 10% was used when bonded with All-Bond$^{(R)}$ 2, a NTG-GMA/BPDM system. Aelitefil$^{TM}$ composite resin was bonded to the pretreated dentin specimen with the use of All-Bond$^{(R)}$ 2 or One-Step$^{TM}$ dentin bonding agent. After the bonded specimens were stored in $37^{\circ}C$ distilled water for 24 hours, tensile bond strength was measured. The fractured dentin specimens were examined under the scanning electron microscope. The results were as follows : Benzalkonium chloride application after acid-treatment resulted in decrease of dentin bond strength of One-Step$^{TM}$, a BPDM/HEMA system (p>0.05). Benzalkonium chloride application did not exert any influence on dentin bond strength of All-Bond$^{(R)}$ 2, a NTG-GMA/BPDM system (p>0.05). There was no relationship between the concentration or application method of benzalkonium chloride and the dentin bond strength of One-Step$^{TM}$ or All-Bon$^{(R)}$ 2 (p<0.05). On SEM examination of the fractured dentin-resin interface, while mixed failure was prominent in dentin bonding with One-Step$^{TM}$, adhesive and mixed failures were seen together in dentin bonding with All-Bond$^{(R)}$ 2 regardless of the concentration and application method of benzalkonium chloride.