• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.778-781
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• 2004

This paper summarizes the results of push-out test specimens with a new type of shear connector called ㄱ type perfobond rib. This connector is a flat steel plate with a number of holes punched through and strengthen rib's head part. According to experiment result, ㄱ type perfobond rib shear connector appeared that resistance force is increased than stud shear connector by $108\%$ and perfobond rib shear connector by $26\%$. The results obtained indicate that the perfobond rib connector is a viable alternative to the headed studs. An appreciable improvement in the shear capacity of the connection was observed when additional reinforcing bars were passed through the perfobond rib holes. For composite beams with concrete filled steel tubes, ㄱ type perfobond shear connectors exhibit adequate ductility and substantially higher capacities.

• Structural Engineering and Mechanics
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• v.28 no.2
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• pp.239-257
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• 2008

Double-sided punched metal plate timber fasteners present projections on both sides, which offer improved joint fire resistance and better joint aesthetics. In this paper, 3-D nonlinear finite element models were developed to simulate double-sided nail plate fastener timber joints. The models, incorporating orthotropic elasticity, Hill's yield criterion and elasto-plasticity and contact algorithms, are capable of simulating complex contact between the tooth and the timber and between the base plate and the timber in a fastener. Using validated models, parametric studies of the double-sided nail plate joints was undertaken to cover the tooth length and the tooth width. Optimal configuration was assumed to have been attained when increase in nail plate tooth width did not result in a raise in joint capacity, in conjunction with the optimum tooth length. This paper presents the first attempt to model and optimise tooth profile of double-sided nail plate fastener timber joints, which offers rational designs of such fasteners.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.267-272
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• 2008

The purpose of this study is to improve the environmental applicability of nonwovens by using special composition. Polypropylene spunbonded and needle punched nonwovens which have the lower cost than polyester nonwovens were used as the raw materials to manufacture the natural fiber used nonwoven geotextiles. These geotextiles were made by use of the thermal bonding methods and composed of jute(or flax)/polypropylene staple fiber blends were obtained in consideration of environmental application. Finally, the engineering properties of natural fiber used nonwoven geotextiles were investigated as eco-friendly materials.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.410-413
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• 2006

The ㄱ type perfobond rib shear connector is a ㄱ type flat steel plate with a number of holes punched through. This connector can be effectively used in girder with high shear. The ㄱ type perfobond rib shear connector exhibit very stiff behaviour under service load conditions and also had the characteristic of retaining a significant amount of load after the attainment of ultimate capacity. The ㄱ type perfobond rib shear connector with safety factor of 3 is applied shear connector of CFT composite girder. From static test result of CFT composite girder, relative displacement of 0.01mm measured at the service load moment. At design of the ㄱ type perfobond rib shear connector, applying safety factor of 3 was more conservative than test result.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.348-352
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• 1992

At present, the manufacturing industry is in a process of great change of circumstances like meeting demands to involve a great variety of types and shorter product life and thus more flexible manufacturing. These changes cause the larger number of different tools and frequent tool changes, which lead to the considerable losses in productive time and the high amount of capital tied up in the tool area. In our country, for the most part, the individual tool are still being presetted according to a data sheet and the measured values are entered, output in a list manually or via punched tapes. This usually takes a considerable amount time and lead to a high error rate. This paper describes a computer controlled tool data management system combined with the bar code tool identification labeled on cutting tools.

• Laser Solutions
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• v.2 no.3
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• pp.32-41
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• 1999

This study is about Jig used in wiring when we make Probecard and Large Scale Intergrated Electronic Circuit. The most universal wiring method is molding with Bond. Polymer film is punched down and adhesives is applied after wiring. Due to shrinkage and modification many problems still have happened in the process of molding. To solve these problems, ceramic plate was introduced in the study. Using Laser, an experiment of microhole treatment on ceramic plate was proceeded. Laser energy, assistance gas, and special features by purity degree were analyzed with the 35W low capacity YAG-Laser. In the condition of energy 0.08J, frequency 20Hz and interval time 200$mutextrm{s}$, about 70${\mu}{\textrm}{m}$ microhole was adequate for the Probecard Jig. In the purity experiment of ceramic materials, high purity ceramic met with good result for microhole. But the price is too high. The shape and size of holes machined combustion gas $O_2$ were better than those in $N_2$ and Ar, the inert gas.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.48-53
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• 1993

At present, the manufacturing industry is in a process of a great change. There is a demand for a variety of types and shorter product life. The change increases the number of different tools and frequencies of tool changes. For the most part, the tools are presetted and offset values are entered manually or via punched tapes to NC machines. Thus a large amount of capital is tied up in the tool area and considerable productive time is lost. Consequently, there is a need for improvement in tool management. This paper describes a computer controlled tool data management system which include: 1) tool identification with bar code. 2) computer aided management and updating of tool data. 3) tool data communication with tool presetter, CNC, etc.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.24-26
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• 1995

The Development of A.C. Induction Motor for Railway Rolling Stock. The traction motor is designed as 4-pole induction motor with self ventilation. The winding insulation is throughout of materials of class C. The rotor is designed as a squrrel rotor with copper bar and casting. The rotor speed is detected by means of a pulse generator. The newer tection motor have no casting(frame). Punched-in holes make up the air duct and transfer the heat losses in complete. Maximim motor rpm is higher due to rotor construction. New is the entry of water-cooled traction motors in urban, However the water cooling design in - unfortunately - not applicable in traction motor.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.731-736
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• 2000

An optimal design method is adopted for a spacer grid in nuclear power plant. It is made of punched sheet metal process, functioning as springs and dimples supporting fuel rods. For stress analysis of the assembled fuel rod support, a typical cell out of the repeated pattern in the assembly is modeled using 4-node shell elements. A commercial code, ABAQUS, is used for detailed analysis of contacting phenomena with friction. For the optimization, design varibles are taken from geometric parameters representing the shape of the bent leaf spring part and mating contact region with fuel rod. Objective function is considered in relation to mechanical functions and durability. Maximum yon Mises stress is considered in relation to constrained contact stress.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.6 no.1
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• pp.23-25
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• 1976

The patient, 19 years old male, visited with complaints of trismus and consults for construction of denture. 4 years ago, he received /sup 60/Coteletherapy of left laryngeal area for treatment of throat tumor. Clinical apperance showed rampant dental caries, multiple root rests, xerostomia, disturbance of mandibular growth and asymmetry of face. Roentgenographic examination disclosed deep cervical caries, destruction of alveolar crest, punched out bone destruction of mandible and maxilla.