• 대한토목학회논문집
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• 제7권1호
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• pp.93-101
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• 1987

용접부(鎔接部)에서 잔류응력(殘留應力)은 용접열(鎔接熱)에 의한 국부(局部) 가열(加熱)과 불규칙적(不規則的)이고 비교적(比較的) 급속(急速)한 냉각(冷却)으로 유발(誘發)되는 열응력(熱應力)과 구조물(構造物)의 강성(剛性) 및 재료(材料) 등에 의하여 발생(發生)되며, 잔류응력(殘留應力)의 존재(存在)는 취성파괴강도(脆性破壞强度), 피로강도(疲勞强度), 좌굴강도(挫屈强度), 진동특성(振動特性), 부식저항(腐蝕抵抗) 등에 영향(影響)을 미치는 궁극적(窮極的) 요인(要因)으로 간주(看做)됨으로 본(本) 연구(硏究)는 구조물(構造物)의 강도(强度)를 저하(低下)시키고 기능(機能)에 악영향(惡影響)을 끼치는 잔류응력(殘留應力)의 기구학적(機構學的) 특성(特性)을 파악(把握)하기 위하여 SWS 58 강판(鋼板)을 X홈 용접(鎔接)하여 이것을 4단계(段階) 즉 $350^{\circ}C$, $500^{\circ}C$, $650^{\circ}C$, $800^{\circ}C$로 열처리(熱處理)하여 hole drilling method를 사용(使用)하여 잔류응력(殘留應力)을 측정(測定)한 결과(結果), 다음과 같은 결론(結論)을 얻었다. 잔류응력(殘留應力)을 제거(除去)시키는 가장 효과적(效果的)인 온도(溫度)는 $650^{\circ}C$ 정도(程度)이었고, 구멍의 직경(直經)이 구멍의 깊이와 일치할 때 구멍바로 근처(近處)의 소성변형(塑性變形)은 완전(完全)히 해방(解放)되었으며, 경도시험(硬度試驗)을 통(通)해 열처리(熱處理) 후(後) 열영향부(熱影響部)의 높은 경도(硬度)가 모두 삭감(削減)되는 것을 알 수 있었으며 또한 잔류응력(殘留應力)에 끼치는 용접입열(鎔接入熱)의 영향(影響)은 입열량(入熱量)의 표준(標準)보다 1/4 이상(以上), 이하(以下)인 경우 잔류응력(殘留應力)은 용접입열(鎔接入熱)에 큰 영향(影響)이 없음을 알았다.

• 한국재난정보학회 논문집
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• 제15권3호
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• pp.380-390
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• 2019

연구목적: 최근 전기레인지의 사용증가와 더불어 화재도 증가하고 있다. 전기레인지 중 대표적인 인덕션과 하이라이트 방식에 대해 구조 및 작동방법을 알아보고 화재위험성을 살펴보고자 하였다. 연구방법: 두 방식에 대하여 연소실험, 전열실험, 발화실험 등을 실시하였다. 연구결과: 하이라이트 전기레인지는 키친타월이 2분 후 연소되었고, 조리를 마친 후 잔열이 식는데 약 25분이 소요되며, 니크롬선의 붉은 기운이 3~4분 만에 사라지고 불꽃이 보이지 않았다. 결론: 실험 결과 하이라이트 방식은 화상 및 화재 위험성이 존재하며, 특히 상판에 균열이 있을 경우 화재 및 폭발의 위험성이 있음을 알 수 있었다.

• Structural Engineering and Mechanics
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• 제9권4호
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• pp.375-382
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• 2000

Experimental investigation into the cyclic behaviour of sand plast brick masonry was performed on forty two square panels. The panels were subjected to cyclic uniaxial compression for two cases of loading: normal to bed joint and parallel to bed joint. Experimental data were used to plot the unloading-reloading curves for the entire range of the stress-strain curve. Mathematical expressions to predict the reloading and unloading stress-strain curves at various values of residual strain are proposed. A simple parabola and an exponential type formula are found adequate to model the unloading and reloading curves respectively. The models account for the potential effects of residual strain on these curves. Comparison of test results with the proposed mathematical expression shows good correspondence.

• 천문학회보
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• 제40권1호
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• pp.74.3-74.3
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• 2015

We present 2D- photometric decompositions of ~1,200 nearby dwarf galaxies. Our representative sample is derived from 'A catalog of Visually classified galaxies in the Local Universe'(Ann, Seo and Ha APJS,,,2015) of which galaxy morphological types are determined by visual inspection of color images using the Sloan Digital Sky Survey data release 7. In this catalog, dwarf galaxies were divided into 5 subtypes : dS0, dE, dSph, dEbc, dEblue with distinction of the presence of nucleation in dE, dSph, and dS0. The dSph types are less brighter than other types, and galaxies with nuclei are slightly brighter than those with no nuclei in the same types. Sersic index n have a range 1~1.5, and $dE_{un}$ and $dSph_{un}$ galaxies have n less than 1, and $dSph_n$ galaxies have largest values. We performed two-dimensional decomposition of galaxies using GALFIT, and analyzed their structural components, and residual features which are seen in the residual image.

• 대한화학회지
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• 제56권2호
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• pp.257-263
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• 2012

The selection of suitable delignification conditions and optimization of process variables is crucial to the successful operation of chemical pulping processes. Soda pulping of Carpolobia lutea was investigated, as an alternative raw material for pulp and paper production. The process was optimized under the influence of three operational variables, namely, temperature, time and concentration of cooking liquor. Equations derived using a second - order polynomial design predicted the pulp yield and lignin dissolution with errors less than 8% and 11% respectively. The maximum variations in the pulp yield using a second order factorial design was caused by changes in both time and alkali concentration. Optimum pulp yield of 43.87% was obtained at low values of the process variables. The selectivity of lignin dissolution was independent of the working conditions, allowing quantitative estimations to be established between the pulp yield and residual lignin content within the range studied.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 제14회 신호처리 합동 학술대회 논문집
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• pp.747-750
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• 2001

The paper presents an algorithm for estimating the variance of additive zero mean Gaussian noise in an image. The algorithm uses the wavelet transform which is a good tool for energy compaction. The algorithm consists of three steps. At first, high frequency components, wavelet coefficients in HH band, are generated from a noisy image by the wavelet transform. In a second step, high frequency components which are out of the noise range ate eliminated. Finally, if the image has many components eliminated in the previous step, then its noise estimated value is reduced. Experimental results show that the wavelet filter has better performance than the other high pass filters such as a Laplacian filter, residual from a median filter, residual from a mean filter, and a difference operator. In various images, the algorithm reduces 50% of estimated error on an average.

• 대한치과보철학회지
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• 제36권1호
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• pp.18-25
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• 1998

The purpose of this study was to determine how to use soft relining material by observing an amount of denture displacement according to the different base area of residual ridge and thickness of soft relining material under masticatory force. Stone models that simulated residual ridge were made with different amount of denture base area and denture was fabricated by conventional heat curing resin with usual manner on the model and relined by silicone type soft relining material with different thickness. Specimen was examined the amount of denture displacement by Instron within range of normal occlusal force. The results were as following : 1. The increasing rate of denture displacement was higher than that of soft relining material thickness. 2. The amount of denture displacement decreased 1.7 times when base area became double at same thickness of soft relining material 3. The increasing rate of denture displacement was higher than that of occlusal force

• Journal of Mechanical Science and Technology
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• 제17권4호
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• pp.477-483
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• 2003

An independent kinematic hardening material model in which the reverse yielding point is defined by the Bauschinger effect factor (BEF) , has been defined for stainless steel SUS 304. The material model and the BEF are obtained experimentally and represented mathematically as continuous functions of effective plastic strain. The material model has been incorporated in a non-linear stress analysis for the prediction of reverse yielding in thick-walled cylinders during the autofrettage process of these vessels. Residual stress distributions of the independent kinematic hardening material model at the onset of reverse yielding are compared with residual stresses of an isotropic hardening model showing the significant effect of the BEF on reverse yielding predictions. Critical pressures of direct and reverse yielding are obtained for the most commonly used cylinders and a range of permissible internal pressures for an efficient autofrettaged process is recommended.

• 한국생활과학회지
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• 제16권1호
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• pp.75-87
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• 2007

The purpose of this study was to classify the financial strategies in elderly households. The data of 4,577 households with all ages and 1255 elderly households is from the Korean Labor and Income Panel Study(2000, 2003). The data were analyzed by various statistical methods such as frequency, mean-test, Duncan's multiple range test, k-mean cluster analysis and logistic regression. Findings were as follows; First, the classified household financial strategy types were Residual(44.3%), Financial Assets(24.0%), Informal Institutional(19.7%), Diversified Portfolio(7.6%), Real Estate(4.5%). Second, the criteria of classification of the financial strategies were relative, not absolute. Third, households(both elderly households and all households) that employed a diversified portfolio strategy had the greatest net wealth.

• 대한전기학회논문지
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• 제43권2호
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• pp.268-277
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• 1994

Current sensor using Hall device is an instrument of detecting a current by Hall effect. The existing current sensor is ordinarily worked by concentrating electromagnetism produced around the conducting wire turned iron core. The tiny curren, however, could not be accurately detected by the instrument owing to influence of residual magnetism exisisting in iron core, and the result of detecting is also somewhat on the large side. kAccordingly, We fabricated a new type of instrument minimizing the influence of residual magnetism existing in iron core and detected the tiny DC current accurately by taking advantage of magnetic modulation. The range of measuring DC current is 0[mA]-100[mA] and the maxiumm Linerity tolleance by the result of detecting current, can be reduced less than 3 percent.