• Journal of Welding and Joining
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• 제26권1호
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• pp.63-68
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• 2008

This paper has aimed to prevent excessive heat input by controlling arc distribution and heat input capacity with pulse GTAW in order to improve weld quality in 0.08mm pressure gauge diaphragm and flange welding parts. A design of experiment was designed using Box-Behnken method to optimize a welding process. The pulse GTAW parameters such as pulse current, base current, pulse duty, frequency and welding speed were set to input variables while hydraulic pressure that represents welding characteristics in diaphragm and flange joint were set to output variables. Based on the test result, a second regression equation was obtained between input and output variables and turned out significant. Besides, an influence of parameters has been confirmed through response surface analysis using the second-order regression equation and optimum welding condition was obtained through a grid-search method. The optimum welding condition was set to pulse current 84.4(A), base current 29.6(A), pulse duty 58.8(%), frequency 10(%), and welding speed 596(mm/min). Then, decent bead shape was acquired with no excessive heat input under the $2.3kgf/cm^2$ of hydrostatic pressure.

• 한국지반공학회논문집
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• 제25권5호
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• pp.39-46
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• 2009

본 연구에서는 조립질의 퇴적층이 깊게 분포되어 있고 지하연속벽과 지반앵커로 구성된 굴착현장을 선정하여 흙막이 벽계와 배면지반의 수평변위 비교, 벽체 내부에 깊이별로 설치된 토압계와 앵커 두부에 설치된 축력계로 부터의 토압과 축력의 변화등을 정밀하게 평가분석 하였다. 분석결과 강성벽계의 수평변위는 벽체 내부에 설치된 지중경사계로 측정된 결과가 보다 합리적인 것을 알 수 있었다. 그리고 단계별 굴착에 따른 토압의 변화를 분석한 결과, 굴착이 진행됨에 따라 지반앵커의 선행 긴장력으로 인해 배면 토압은 점차 증가하는 경향을 나타내고 있었으며, 지하연속벽이 강성 벽체지만 퇴적층이 깊고 굴착 깊이가 깊은 경우에는 연성벽체에서 경험적으로 평가된 경험토압과 유사한 결과가 나타남을 확인하였다.

• 한국진공학회지
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• 제6권3호
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• pp.220-226
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• 1997

실리콘 미세가공기술로 형성된 프레임 모양의 실리콘 기판에 의해 지지되는 -$Si_3N_4/300 nm-SiO_2/150 nm-Si_3N_4$ 광반사막을 제조하였으며, 이것을 광섬유와 결합하여 강도형 다모드 광섬유 압력센서를 제작하고 그 특성을 조사하였다. $Si_3N_4/SiO_2/Si_3N_4$다아아 프램을 광반사막으로 사용하기 위하여 이 다이아프램의 뒷면에 NiCr 및 Au 박막을 각각 진 공증착하여 광반사막에서의 광투과에 의한 광손실을 수%로 감소시킬 수 있었다. 유전체 다 이아프램의 상하에 각각 있는 $Si_3N_4$막은 KOH 수용액에 의한 실리콘 이방성 식각시 자동식 각 정지층 역할을 하여 다이아프램 두께의 재현성이 우수하였다. 다이아프램의 크기가 3$\times$ 3$\textrm{mm}^2$, 4$\times$4$\textrm{mm}^2$ 및 5$\times$5$\textrm{mm}^2$인 센서는 각각 0~126.64kPa, 0~79.98kPa 및 0~46.66kPa의 압력범위에서 선형적인 광출력-압력 특성을 나타내었으며, 이들 센서의 압력감도는 각각 약 20.69nW/kPa, 26.70nW/kPa 및 39.33nW/kPa로서, 다이아프램의 크기가 증가할수록 압력감 도도 증가하였다.

• 대한조선학회논문집
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• 제46권3호
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• pp.279-289
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• 2009

For a Product Oil Carrier, longitudinal bulkhead as well as transverse one is corrugated shape in general and intersection part of bulkheads is utilized for a pipe trunk. Since lower and upper stools are to be connected with all of longitudinal and transverse bulkheads, they have a uniform height respectively. The purpose of this study is the development of design system for the minimization of total weight of longitudinal and transverse bulkheads at the initial design stage. In this study, the beam element models for longitudinal and transverse corrugated bulkheads are established and they are applied to the structural analysis. For the practical design, the selection and the position of an additional pipe trunk are considered in this study. In addition the required minimum distance between the bracket installed along the web of corrugation at lower stool and the diaphragm is taken into consideration during optimization process. Evolution strategy(ES) is adopted as an optimization technique.

• 한국철도학회논문집
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• 제8권1호
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• pp.41-50
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• 2005

Steel -Concrete Composite two girder railway bridges applying high performance steel with extra thick plate have economic and aesthetic advantages due to the simplification of manufacturing and construction process. However, steel bridges are seldom adopted in domestic railway bridge, since steel bridges are not efficient as R.C bridges considering dynamic characteristics and noise, etc. While highway bridges do not have lower horizontal bracing and larger interval of diaphragm cross beam, railway bridges install lower horizontal bracings to control the torsion due to heavy eccentrical line load. Accurate finite element analysis were performed with the parameters of existence of bracing and bracing shape, with the cross beam interval and stiffness, etc. To find out the effects of secondary members such as horizontal bracings and diaphragms, static md dynamic analysis have been performed by using finite element method. In this study, few member plate-girder bridges are analyzed with variable span lengths to examine the dynamic behavior and limits of damping. And though lateral bracings are members against torsion, but lateral bracing's absence is no big problem. Time history analysis using mode superposition method makes proof of this result.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.517-520
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• 2004

Concrete Filled steel Tube pipe structure is a rational type of structure that maximizes performance by combining the strong points of steel frame and concrete. In the structure, the confining effect of steel pipes increases the bearing power of infilled concrete and the strengthening of local bucking of steel pipes by infilled concrete increases the bearing power of members. and these result in the reduction of cross-sectional area and high transformation capacity. Moreover. the structure is economically efficient and widely applicable that it is used from super-high buildings to residential, business and apartment buildings. It enables the construction of multi-story buildings with long spans using columns of small cross-sectional area. In case of diaphragm, however, it is difficult to confirm the compactness of the closed inside of steel pipes. The present study examined the properties of super-high strength concrete over 80MPa by comparing it with 40MPa concrete through heat conductivity and length change tests based on a mixture ratio satisfying the mixture goal presented in the guideline for the design and construction of concrete-filled steel pipe structure. and evaluated the performance of super-high strength concrete according to the shape and size of the aperture ratio of diaphragm.

• 조명전기설비학회논문지
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• 제16권3호
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• pp.55-60
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• 2002

우리나라에서 판매되고 있는 가정용 네블라이져는 2.5[kg/$\textrm{cm}^2$]의 피스톤방식의 컴프레셔를 사웅하여 소음이 클 뿐 아니라 효율면에서 문제점을 가지고 있다. 이러한 것들을 개선하기 위해서 0.6[kg/$\textrm{cm}^2$]의 다이아후렘방식의 모터를 사용하여 적은 소음과 적은출력으로 비슷한 효과를 가져오게 하였으며, 네블라이져의 핵심인 노즐부분에서 충돌부의 충돌단면적 을 넓게 하였고 V형의 경사를 주는 등 설계상의 변화를 주어 약액이 더 미세하게 깨어지도록 하여 치료효과를 높이는 결과를 얻었다.

• 대한가정학회지
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• 제28권1호
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• pp.1-7
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• 1990

This study was carried out to investigate the influence of the various physiological function caused by girdle wearing. The four experimental methods used in this study are as follows. For example, the Reentgen photographing, body measurement by Sliding Gauge, mensurement of the electrocardiogram, measurement of the pulse and the blood pressure. The results of the investigation were as follows; 1. In the change of the various organs by Roentgen photographing, the diaphragm rised a little than normal position. The heart and stomach inclined to right side and the shape of stomach and duodenum are longer than the length of normal shape. Especially the phlorus of stomach was pressured strongly. 2. In the experimental change by the Sliding gauge and body measurement, the waist, hip and theigh girth of wearing-girdle reduced than at the no-girdle. The protruson of abdomen and hip section of wearing-girdle and the phenomenon of Hip-Up showed. 3. The difference by measurement of the electrocardiogram wasn't showed. The pulse of the wearing-girdle was increased slightly than the no-girdle. 4. The blood pressure of the wearing-girdle decreased slightly than the no-girdle.

• 한국연소학회지
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• 제18권3호
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• pp.31-37
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• 2013

Numerical simulations are conducted to investigate the feature of spontaneous ignition of hydrogen within a certain length of downstream tube released by the failure of pressure boundaries of various geometric assumption. The results show that the ignition feature can be varied with the shape of pressure boundary. The ignition at the contact region are developed at the spherical pressure boundaries due to multi-dimensional shock interactions, whereas the local ignition is developed in limited area such as boundary layer at the planar pressure boundary conditions. The spontaneous ignition inside the tube can be generated from the reaction region of only boundary layer regardless of existence of the reaction of core region.

• 동력기계공학회지
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• 제15권5호
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• pp.61-66
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• 2011

Recently, the speed reducer which is applied to robot has conducted a steady development on developments in the field of robotics. Among them, Harmonic drive is a high-stiffness, precision-controlled speed reducer and has high precision, compact, light in weight and high-reduction-ratio characteristics. The feature of flexspline of Harmonic Drive are two types. One is Cup type, the other is Silk Hat type. Silk Hat type is used in case of lighter and more compact in spatial because Silk Hat Type is hollow. According to the shape of silk hat, diaphragm is fractured because stress is concentrated. In this paper, the various shapes of silk hat are suggested to improve the durability of silk hat. And in the case of each shape, a study on stress and deformation using the FEM tool was carried out on flexspline.