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고분자 튜브 압출성형기의 Braker Plate 구조 개선에 관한 연구
김재열,최진호,박대광 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-
Many experiments and various simulation techniques are used for the analysises of models used for extrusion modeling in these days. Especially the 3-dimensional technique is used widely among them. We usually use the 3-dimensional technique because the simple 2-dimensional analytical technique can't perform the analysis of the model which has complicated shape structure. As a result, the 3-dimensional technique is used for the extrusion molding of complicated structure, measurement of friction and density, and appiled mechanism of polymer resin. The Braker Plate, key subject of this article, is added to the extruder for extrusion molding of polymer resin. This Braker plate plays the important role to convert the rotation motion of polymer resin passing the screw into the linear motion before passing the dice. Also, Braker Plate's round hole size and number affects the extrusion molding of polymer resin directly. But these Structural improvements and analysises of Braker Plate are hardly studied. This study will achieve the structural improvements through 3-D modeling and ensure the produceable stability by carrying dynamic Characteristic through CFdesign, heat/flow analysis program.
임광희,조영재,이길성,심재기,김영남,양인영 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.1
최근 탄소섬유 강화 복합재료(이하 CFRP)는 비강도, 비강성이 높아 경량화가 요구되는 우주항공분야에서 구조용 재료로 널리 이용되고 있다. 본 연구에서는 CFRP 적층쉘의 적층구성 및 곡률반경에 따른 관통 특성을 고찰 하고자 한다. 실험에 사용된 복합재료는 일방향 프리프레그시트로서 적층방법은 〔0₃/90₃〕, 〔0₂/90₂〕s,와 〔0₂/90₃/0〕s, 〔0/90₂/0〕 2계면과 4계면으로 적층하였다. 그리고 다양한 곡률 반경을 적용하였다. (R= 100, 150, ∞). 적층순서에 맞게 적층된 시험편은 경화온도 130℃에서 진공백 성형과정을 오토클레이브로 제작 하였으며 100x140mm 크기로 절단 하였다. 시험편은 강구로 관통시켰으며 ballistic-screen sensor로 속도를 측정하여 충격전 운동에너지와 충격 후 운동에너지를 구할 수 있다. 흡수에너지는 곡률이 커질수록 증가하였으며 4계면 시험편보다 〔0₃/90₃〕s 와 〔0₂/90₂〕s 적층구조를 갖는 2계면 시험편이 흡수에너지가 더 높게 나왔다. Currently, carbon-fiber reinforced plastics (CFRP) are widely used in both space and civil aircraft due to their superior stiffness and strength to weight ratios compared to conventional metallic materials. This paper is to study the effects of curvature and staking sequence on the penetration characteristics of CFRP laminated shell. Composite laminates used in this test are CFRP orthtropic laminated plates, which are stacked with two-interfaces 〔0₃/90₃〕s, 〔0₂/90₂〕s and 〔0₂/90₃/0〕s. 〔0/90₂/0〕s. They are manufactured to varied curvature radius (R= 100. 150, 200 mm and ∞). They are cured by heating to the appropriate hardening temperature(130℃) by mean of a heater at the vacuum bag of the autoclave. Test specimens were prepared with dimensions 100mmx140mm. When the specimen is subjected to transverse impact by a steel ball, the velocity of the steel ball was measured both before and after impact by determining the time for it to pass two ballistic-screen sensor located a known distance apart. Absorbed energy increased as the curvature increased. 〔0₃/90₃〕s and [0₂/90₂〕s specimens, which is small interlaminar number, was higher than fore interlaminar specimen.
저작근 골막하 박리를 이용한 만성 재발성 탈구의 치험례
심재환,김기홍,문진석,민병진,이원학,홍광진 大韓顎顔面成形再建外科學會 2003 Maxillofacial Plastic Reconstructive Surgery Vol.25 No.3
Chronic recurrent dislocation(CRD) of the jaw has various etilogical causes, including trauma, congenital or acquired neurological illness, ingestion of certain medicines, incorrdination of the neuromuscular astivity of the chewing muscles, articular anatomical alteration, etc. Various surgical methods have been advocated for the treatment of the CRD. They may be divided into two groups: procedures designed to limit translation of the condyle and procedures eliminating obstacles in the condylar path. Hypomobility of mandible can be developed after BSSRO and it is probably caused by scar contracture, atrophy, and myofibrosis. Many authors, therefore, emphasized the importance of physical therapy especially after BSSRO to prevent the complication. Based on that idea, we designed more conservative surgical method to limit mandibular openning compared the methods that previously introduced and tried to treat the CRD. This new method consists of extensive subperiosteal dissection of masseter and the temporalis muscle under local anesthesia and use of intermaxillary elastics for some periods.
제7차 교육과정에 따른 산ㆍ염기 단원의 STS과학 교육에 적합한 CBL 실험 프로그램의 개발
이광필,김동화,최성호,류재정,이무상 慶北大學校 師範大學 科學敎育硏究所 2001 科學敎育硏究誌 Vol.25 No.-
This study developed the 'advanced-supplementary' course experimental program with CBL(Calculator-Based Laboratory) system in conformity with the reform of the 7th science curriculum and applied the CBL experimental program to 'acid-base' chapter of middle-high school. The results of this study shows that a practical use of CBL system as powerful instrument can be applied to experiment program of 'acid-base' chapter in order to causes learner's motivation and enlarge a sphere of inquiry-activity in science.
Zinc Surfactant Effects on Nr/Tespd/Silica and SBR/Tespd/Silica Compounds
( Kwang Jea Kim ),( John VanderKooi ) 한국고무학회 2004 엘라스토머 및 콤포지트 Vol.39 No.4
N/A The effects of zinc surfactant (ZB) on the bis(triethoxysilylpropyl)disulfide (TESPD)-silica mixture in natural rubber (NR) and solution butadiene-co-styrene rubber (S-SBR) were compared with respect to their rheological property, processability, physical properties, and silica dispersion. In the NR compound, addition of the ZB increased the reversion resistance time (T-2), the tensile modulus, and the BO time; however, lowered the viscosity, the HBU, and tans values. In the S-SBR copound, addition of the ZB increased the tans values while lowered the T-2, the tensile modulus, the BO time, the viscosity, and the HBU of the compound. In the NR compounds, addition of the ZB significantly increased the processability and mechanical property. However, in the S-SBR compounds, it improved the processability the mechanical property was not improved.
Kwang-Jea Kim 한국탄소학회 2009 Carbon Letters Vol.10 No.2
Various silanes, amino silane, vinyl silane, TESPD, and ZS (TESPD/zinc soap complex), are added into chlorinated isobutylene-isoprene copolymer (CIIR)/hard clay/carbon black (CB) compound and they are investigated with respect to the vulcanization characteristics, the processability, and the mechanical properties. In hard clay/CB filled system, only ZS silane added compound shows both lower Mooney viscosity and extrusion torque while vinyl silane added compound showed only a lower extrusion torque. All the ZS added compounds showed the lowest viscosity among them. The silane added compounds showed an increased modulus. In 'fatigue to failure' count test, the ZS added compound showed superior counts compared to other silane (amino, vinyl, TESPD) added compounds. The mechanical properties were significantly increased when the S2 and ZS were added into CIIR/hard clay/CB compound. The ZS added compounds showed a significant improvement on elongation modulus.
Kwang-Jea Kim 한국탄소학회 2009 Carbon Letters Vol.10 No.2
Various silanes, amino silane, vinyl silane, TESPD, and ZS (TESPD/zinc soap complex), are added into chlorinated isobutylene-isoprene copolymer (CIIR)/soft clay/carbon black (CB). The vulcanization characteristics, the processability, and the mechanical properties are measured. In soft clay/CB filled CIIR system, there are no significant changes in Mooney viscosity among compounds. Vinyl silane added compound shows a low extrusion torque. All the silane added compounds shows an increased modulus. The mechanical properties are significantly increased when the S2 is added into CIIR/soft clay/CB compounds.
Kim, Kwang Su,Kim, Hun Mo,Kim, Youn Jea Scitec Publications Ltd. 2007 Solid State Phenomena Vol. No.
<P>Because of design and manufacturing costs, it is important to predict an expected life of bellows with component stresses of bellows as its design factors and material characteristics. Besides, if the reliability of the bellows in a bellows-seal valve is not properly assessed, leakage would be occurred easily before the expected life of the bellows. In this study, numerical analyses are carried out to elucidate the thermal and flow characteristics with bellows-seal globe valve for high temperature and for high pressure conditions using FSI (Fluid-Structural Interaction) technique. Thermal stress affecting bellows life is depicted with its axial displacement to assess the reliability of the bellows. In addition, we made a basic fuzzy algorithm to add new design parameter. As the result of this study, we got the reasonable coefficients for valve and thermal stress for bellows, compared with existing coefficients and calculated values. Also, since the maximum thermal stress of the bellows is below a general yield stress of used material, the reliability of the bellows is established.</P>