• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.2
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• pp.99-104
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• 2015

This study analyzed the effects on displacement and stress as a result of improving the profile fastening method targeting rectangular-shaped and cube-shaped specimens. For the rectangular-shaped specimens, the improved fastening method reduced maximum displacement to 41.7% and maximum stress to 18.3% compared to the existing fastening method. For the cube-shaped specimens, maximum displacement and maximum stress results were found to be similar to those of the rectangular-shaped specimens. Thus, as a result of comparing the stress and displacement of the existing and improved fastening methods, it was found that the improved fastening method is superior to the existing fastening method in terms of load support.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.10a
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• pp.63-66
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• 2003

남획에 의한 어자원 감소와 오염으로 인한 해양 환경의 변화, 그리고 주변국과의 어업협정 체결 및 수입 개방 조치 등에 의한 어업정책의 변경으로 어업인의 소득이 심각한 타격을 입게 되면서, 어획 성능이 우수하고 조업 방식이 간편하며 소요 경비가 절감되는 어구어법으로의 전환이 빠르게 진행되고 있는 실정이다. 삼중자망은 홑자망, 통발에 비해 조업방법이 간단하고 특별한 어로설비를 필요로 하지 않으며 우수한 어획성능을 가지고 있어 어업인들이 선호하고 있으나 심각한 자원 남획을 유발하는 어구이기 때문에, 삼중자망의 불법사용에 대한 규제와 단속을 지속적으로 실시하고 있다. (중략)

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.62-65
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• 2011

액체로켓엔진용 극저온 산화제 고압 배관 기술 개발을 위해 시제품을 제작하였다. 기술 개발 시제품은 체결용 플랜지, 직관, 곡관, 벨로우즈, 분기구로 구성하였다. 액체로켓엔진용 극저온 산화제 고압 배관은 터보펌프에서 토출된 고압의 극저온 산화제를 연소기로 공급하는 경로이므로 극저온, 고압의 작동환경에서 구조적 안정성을 가져야 한다. 따라서 본 제작공정 개발에서는 극저온을 고려한 구조해석을 수행하여 적합한 소재를 선정하였으며, 공정개발과 특수공정을 적용하여 시제품을 제작한 후 구조강도 시험을 수행하였다. 본 개발을 통해 액체로켓엔진에 적용되는 극저온 산화재 고압배관을 위한 기술적 기반과 소재 응용기술, 향후 고성능 대형 액체로켓엔진에 적용하기 위한 공정개발을 완료하였다.

• Journal of the Korean Vacuum Society
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• v.11 no.2
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• pp.81-86
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• 2002

With a specific model for the Helicoflex type metal gasket expected to be used in large ports of the KSTAR vacuum vessel, a sealing curve was obtained by measuring the flange tightening properties such as the correlations of the tightening torque(or linear load), displacement to the leak rate. From the experiment results it was found that the leak rate of the Helicoflex seal in the room temperature was bellow $2\times10^{-1}\textrm{mbar\cdot L/s}$ with a tightening torque of 2500kgf . cm using Ml8 bolts.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.4
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• pp.371-392
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• 2011

The purpose of this study was to comparatively analyze the stress distribution according to the inclinations of abutments and angulations of the implant fixtures under occlusal loading force. Three study models with straight and $15^{\circ}$ and $25^{\circ}$-angled abutments were prepared following the insertion of Implants parallel to the long axis of the tooth. Additional two experimental models were fabricated with $15^{\circ}$ and $25^{\circ}$ fixture inclinations. Using ANSYS 11, a finite element analysis program, the magnitudes of stress distribution were analyzed. The magnitude of stress under loading was lowest when the load was applied vertically onto the axis of implant. And the magnitude of stress under compound(vertical+oblique) loading was increased as the inclination of implant abutment and fixture was increase. But, the distribution of stress was different as the loading conditions, because of the horizontal offset. As the offset between the axis of loading and the central axis of the implant increased, the stress was increased.

• Fire Science and Engineering
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• v.34 no.3
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• pp.76-84
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• 2020

Most outlet fires occur around plug pins and plug pin receivers. However, no research has been conducted on ignitions at power connection points. This study confirms the possibility of ignition after incomplete connection, using a stranded wire, to the power connection point of an outlet. The experiment was divided into basic and reproducing experiments. The basic experiment confirmed the possibility of ignition according to the number of wire strands connected to the power connection point, and it identified the characteristics of the residue after the fire. In the reproducing experiment, lamps, vacuum cleaners, and heaters were connected to an outlet to check if the ignition at the connection advanced into a fire. The fire advanced due to the heat and arc generated at the connection point, and partial losses were identified in the U-type holder and clip. Accordingly, the results demonstrate that a fire may occur when the stranded wire is incompletely connected to the outlet. Moreover, it was confirmed that the cause of a fire can be determined based on the characteristics of the residue.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.4
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• pp.432-438
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• 2019

Accurate impression taking for the success of implant prosthesis is a very important process. Methods of taking implant impression include the conventional method using impression coping and impression material, and the digital method using an intraoral scanner and scanbody. However, the impression coping or the scanbody must install after remove healing abutment. Because of this, the dentist must repeat the process of removing and installing the healing abutment, the impression coping or the scanbody several times. In addition, the impression coping or the scanbody rises higher than the occlusal surface, so the patient has the inconvenience of constantly maintaining the open state. Recently, a scannable healing abutment, which can be scanned by a intraoral scanner directly, without the need to remove the healing abutment by applying a scannable part of the scanbody to the healing abutment, was introduced. We present a case of single posterior implant prosthesis using a scannable healing abutment.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.171-175
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• 2010

Various soil characteristics for safe construction is necessary to understand the tests using the samples collected, and head in place an energy evaluation is conducted to evaluate the ground. In-Situ testing ground, Rod length and around the intrusive when the energy loss due to friction has been measured only in the head. Abstract The purpose of this agreement when increasing contract area of Rod agreement to transform the energy attenuation and the attenuation at the energy being delivered to evaluate. To this end, the same material used in the field test, laboratory test to apply Rod diameter and length have been considered, designed to perform the experiment was to use the Rod. Energy that raised at head of Rod, was increased and decreased by contracting type. The energy difference occurs in the head with the tip that shows the energy rating may be required at the tip is showing. Abstract The energy evaluation for the Rod field test to be at the basic sources and will be able to calculate the trusted information are measured from the tip.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.473-479
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• 2020

In this study, the structural experiment was conducted with two types of specimens to investigate the mechanical behavior of the column-rafter-purlin connection of an arch-type greenhouse under monotonic loading. Based on the experimental results, the flexural performance was analyzed for two types of connections, and connection classification was attempted. Type B showed 77% of flexural performance compared to Type A, and both types showed that the rigidity and flexural strength did not reach the level of the full rigid. The behavior of the column-rafter-purlin connection was dominated by local buckling due to deformation of the weld and fasteners. As a result of connection classification by AISC standard, both Type A and B connections showed a result that did not meet the rigid connection performance assumed during design, and were classified as simple connection. Therefore, the connection performance evaluation and classification results show that the greenhouse design should be made in consideration of connection performance and in order to design a reliable greenhouse structure, a study on establishing clear design standards for the greenhouse connection is necessary.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.32-38
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• 2020

Cargo train braking uses the pressure changes in the air braking pipe to operate the braking tightening and releasing service repeatedly. Air-braking release failure means partial braking caused by a failure of the variable load valve after the driver handling the brake release. This phenomenon causes wheel flaws while driving a wagon, resulting in wheel breakage or train derailment. This study developed the air-braking release failure proof valve considering the technical requirements of the railway operation corporations. In addition, a durability test of the valve was carried out using a braking performance simulator, and its operating performance was evaluated from the pneumatic history under cyclic braking conditions. The warranty life of this valve was assessed by performing 160,000 cycles of testing of 12 prototypes in accordance with the zero-failure test method, considering the number of braking cycles while driving the wagon. During the durability test, the pneumatic input time, output time, and release velocity were almost constant. The warranty life of this valve was 59,860 times the 95% confidence level, which means that it can be operated without trouble for four years when the valve is installed in the bogie of the wagon.