• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.493-494
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• 2006

Chip breaker of cutting tool is an important feature to enhance cutting performance. Powder injection molding process was used to produce a triangular-shape cermet grooving insert which has three chip breakers. Attrition milled cermet powders were mixed with wax-based binder system in continuous twin screw extruder. Three-plate injection mold with slide cores was used to produce injection-molded parts. After molding, solvent and thermal debinding was carried out. Sintering was conducted in a batch furnace with a graphite heater. The sintered parts satisfy the requirements of dimensional tolerances and material properties.

• 한국기계가공학회지
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• 제14권6호
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• pp.7-13
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• 2015

The production processes were reviewed through the injection analysis of the shift lever as a core component of an auto lever installed in the automatic transmission of cars. The injection analysis was carried out for the shift lever and rod among the components in a shift lever module. The shift lever and rod are designed for injection molding with the insertion of a tube, a pin cable plate, and a steel rod for securing the strength of the product. The charging time, failure of injection molding, weld line, air trap, and deformation were reviewed according to this insert. Analyses on various gate positions were carried out for reviewing the cultivation and deformation of fiber around major components, such as the generation section of manipulation feeling and assembly section, so that optimal gate conditions might be reviewed and reflected in the mold design. Finally, we plan to compare the analysis results with the production of trial products.

• Journal of Acupuncture Research
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• 제20권4호
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• pp.24-41
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• 2003

Objective: Dopamine activity in thenucleus accumbens is an important neuropharmacological component of morphine reinforcement. In this nucleus a shell and core have been distinguished on the basis of anatomical and neurochemical criteria. Although acupuncture has been standard intervention in many detoxication programs worldwide, the central mechanism by which morphine acts to reinforce behavior remain elusive. The present in vivo microdialysis study was conducted, in freely moving rats, to detect the effects of acupuncture on extracellular dopamine release in the nucleus accumbens. Methods: Male Sprague-Dawley rats received acupuncture for 1 min after injection of morphine hydrochloride (5mg/kg, s.c.). The employed acupuncture needle points corresponded to bilateral Neiguan(PC6) on the pericardium channel, which has been used to treat mental and psychosomatic disorders. Extracellular dopamine and its metabolites were measured every 20 mins for 3 hrs following the subcutaneous morphine injection. Results: Results showed that acupuncture at PC6 significantly attenuated increases in dopamine levels induced by a single acute morphine injection in the nucleus accumbens shell and core, respectively. Conclusions: These results provided strong evidence for acupuncture-mediated reduction in morphine-induced dopamine release in the rat nucleus accumbens.

• 한국정밀공학회지
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• 제24권2호
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• pp.41-46
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• 2007

Recently, the study for filling imbalance in thermoplastic polymer has gradually been increased. However, it is hard to find the researches for filling imbalance of thermoplastic elastomer(TPE). The experiment of filling imbalance was conducted for the three kinds of thermoplastic vulcanizes(TPVs) in the mold with geometrically balanced runner system. In this experiment, the effects of the melt temperature and injection speed on the filling imbalance were investigated. To solve the filling imbalance, Runner Core pin(RC pin) in the experimental mold was adopted and it's effects was tested. In this paper, we present that the insert length of RC pin is dependent to each polymers for optimal filling balance.

• 산업공학
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• 제13권4호
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• pp.591-598
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• 2000

In this paper, an efficient algorithm is proposed to find parting lines(PL) and generate parting surfaces(PS) for an injection mold design. We used a Face-Edge Graph which can be made by B-rep information of solid model. The graph is useful for finding the peripheral-loop edges for PL and the inner-loop edges for hole-patch. The PS can be generated automatically by selecting pre-defined direction lines. We can create a core and cavity molds by trimming the raw stock block with the PS and the upper/lower faces of a product model. We implemented proposed method with Unigraphics API functions and C language, and tesed on Unigraphics V15.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.427-427
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• 2007

The global applications of aspherics surfaces will expand rapidly on the electronics, optical components, communications, aerospace, defense, and medical optics devices etc. Especially, Asymmetric aspheric prism lens is one of the important parts in HMD(Head Mounted Display) because it affects dominantly on the optical performance of HMD. The mold core is the most important device to produce the plastic lenses by injection molding method. In this study, the mold cores for asymmetric aspheric prism lens were processed using fly-cutting method which is kind of the ultra precision processing and form accuracy and surface roughness of the cores were measured.

• 대한기계학회논문집A
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• 제35권12호
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• pp.1627-1633
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• 2011

사출금형은 일반적으로 다수개의 부품을 조립하여 제작되며, 특히 성형부(Core/Cavity)가 금형 형판 내부에 조립되는 구조를 갖는다. 이러한 구조로 인해 금형 조립부 경계면에서는 열접촉 저항이 발생하여 금형 내부의 열전달 특성에 영향을 미치게 된다. 최근 금형의 열접촉 저항이 성형부의 온도분포에 미치는 영향을 수치적으로 예측하기 위한 선행연구가 수행되었으며, 본 연구에서는 이에 기반하여 열-유동 연계해석을 적용함으로써 금형 내부의 열접촉 저항이 사출성형시 유동특성에 미치는 영향을 분석 하였다. 상기 해석결과와 실험결과와의 비교분석을 통해 금형의 열접촉 저항을 고려한 열-유동 연계해석이 기존의 해석방법과 비교할 때 사출성형 유동특성을 보다 향상된 신뢰성으로 예측할 수 있음을 확인하였다.

• 한국항공우주학회지
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• 제47권3호
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• pp.204-211
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• 2019

희박연료 직접분사(Lean Direct injection(LDI)) 가스터빈 연소기에 대한 이상유동 특성을 해석하였다. LDI 연소기에 적용된 환형분사기(hollow-cone spray injector)의 분열을 모사하기 위해 분열모델(Linearized Instability Sheet Atomization(LISA), Aerodynamically Progressed Taylor Analysis Breakup(APTAB)을 적용하였다. 침투깊이와 평균입도(Sauter Mean Diameter(SMD))를 통해 분열모델을 검증하였으며, LDI 연소기에 적용하여 이상유동특성을 분석하였다. 스월인젝터로 인해 Precessing Vortex Core(PVC)가 발생하였으며, 액적들이 PVC를 따라 미립화되는 것을 확인하였다. SMD 결과를 통해 PVC가 회전하는 영역의 외곽으로 즉, 빠른 속도 영역에 액적들이 분포하며, 스톡스수(Stokes number)는 1보다 작다.

• Design & Manufacturing
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• 제17권3호
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• pp.48-54
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• 2023

In this study, an injection mold with ultra-small surface properties was manufactured using nanosecond laser processing. A superhydrophobic characteristic analysis was performed on the PET specimen manufactured through this. To this end, a hydrophobic pattern was defined using the Cassie-Baxter model. The defined features were selected with a spot diameter of 25um and pitch spacing of 30um and 35um. As a result of the basic experiment, it was confirmed that the fine pattern shape had an aspect ratio of 1:1 when the pitch interval was 35um and 20 iterations. Through the determined processing conditions, a hydrophobic pattern was implemented on the core surface of KP4. A specimen with a hydrophobic pattern was produced through injection molding. The height of the molded hydrophobic pattern is 20 ㎛ less than the depth of the core and the contact angle measurement results are 92.1°. This is a contact angle smaller than the superhydrophobic criterion. Molding analysis was performed to analyze the cause of this, and it was analyzed that the molding was not molded due to the lack of pressure in the injection machine.

• 한국전산유체공학회지
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• 제19권1호
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• pp.64-72
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• 2014

This study aimed at assessing the analysis capability of thermal-hydraulic computer code, MARS for the behaviors of the core make-up tank (CMT). The sensitivity study on the nodalization to simulate the CMT was conducted, and the MARS calculations were compared with KAIST experimental data and RELAP5/MOD3.3 calculations. The 12-node model was fixed through a nodalization study to investigate the effect of the number of nodes in the CMT (2-, 4-, 8-, 12-, 16-node). The sensitivity studies on various parameters, such as water subcooling of the CMT, steam pressure, and natural circulation flow were done. MARS calculations were reasonable in the injection time and the effects of several parameters on the CMT behaviors even though the mesh-dependency should be properly treated for reactor applications.