The hydrogen embrittlement could lead to big damages in bolt/nut, fittings, especially, high pressure valve and high leak-proof valve and so on. Thus, special alloy, for instance, such as Monel and Inconel, is recently used to suppress the problems of hydrogen embrittlement in semiconductor facilities, FCEV(fuel cell electric vehicle) and hydrogen gas stations. The purpose of this study is to investigate the characteristics according to ratio change between drawing and extrusion of Monel material within elastic limit through numerical analysis. As the results, the possibility of plastic deformation in case of drawing was greater than that of extrusion. Consequently, the safety factor related to plastic deformation shows the results depending on the ratio change of force between drawing and extrusion.

The present study examined changes in surface shape and pore size observed in carbon black particles isothermally oxidized in an air atmosphere according to their burn-off ratio. Carbon black materials were fed into a horizontal tubular furnace in an air atmosphere when the inside temperature reached 600 °C. Subsequently, while changing the isothermal oxidation time, carbon black samples with different burn-off ratios were obtained, i.e., 10.5, 20.0, 30.4, 41.0, 49.9, 59.8, 71.1, and 81.0%. The scanning electron microscope analysis revealed that the observed carbon black particles were in the form of aggregated primary particles, and that there was no change in the particle size of these primary particles as the burn-off process proceeded. The latter observation supported the observation that pores were formed in the carbon black samples during the burn-off process. Notably, the Brunauer–Emmett–Teller analysis exhibited hysteresis curves, indicating that the corresponding adsorption isotherms were of IV-type. It was also found that the area of the hysteresis curves increased as the burn-off process proceeded. The specific surface area of the raw carbon black sample was 58.00 m2/g, while that of the 81.0% sample was about 4.1 times the figure at 240.27 m2/g. The total pore volume VT was 0.17 cm3/g for the raw sample, and it was much higher for the 81.0% sample at 0.58 cm3/g. The transmission electron microscope analysis showed that the raw carbon black particles had a spherical shape with a smooth surface, but inner pores were not observed. In the 49.9% sample, pores with a size of about 5 nm were observed inside carbon black particles. Notably, the size of the pores observed in the 81.0% sample was about 20 nm and the large pores were created by the collapsing and merging of the smaller pores by oxidation.

This paper studied the differences of the inventories asset turnover change ratio and several characteristics variable between large and small manufacturing firm group. Large and small firm group were determined based on number of labors and asset size. Several characteristics variable of firms such as assets size, sales growth rate, return on assets, leverage ratio, credit rating and age of firm were used to find out the differences of firm group. As a result, the inventory asset turnover change ratio of large firm was 5.16% and that of the middle and small firm was 9.3%. For the large firm, sales growth rate, ROA and credit rating affect inventory assets turnover change ratio. For the middle and small sized firm, Assets size, sales growth rate and credit rating affect inventory assets turnover change ratio. Using this result, we can say that manufacturing company need to consider their firm size and their characteristics to make their own operation strategy of inventory.

Aging of the fire organizations, typical disaster response agencies also will be in serious problems with aging society. It is expected that the ratio of more than fifties will reach 31~40% after 10~15 years in Seoul fire organization. This Aging of firefighters can bring about a serious problem in disaster and safety management, since firefighters require robust fitness and healthy bodies in disaster situations. In this study, after the analysis of aging status and trend of firefighters in Seoul, I have an empirical analysis about the impact this aging has on organization effectiveness and QA. As a result, the increase of the elderly reduced organization effectiveness and QA. In addition, in the group consisting of less than 50, it is expected to increase the organization's effectiveness and QA activities through field activity to improve the professional skills with age, but could not be confirmed. In the group consisting of more than fifties, it was found that aging had a significant negative impact on organizational effectiveness and QA activities as factors, including physical deterioration by aging.

Active front steering(AFS) system is able not only to vary steering ratio between steering wheel and tire wheel but also to steer front tires independently. In this paper, steering gear ratios and an active steering algorithm are proposed for the AFS system. Steering gear ratio is a function of vehicle speed and steering angle. Active steering is generated when the error of yaw-rate is larger than some threshold. To verify the performance of yaw stability, hardware-in-the-loop simulation system is made up of column type active steering system, driving display, steering effort reaction system and controller

The object of this study is to investigate the penetration characteristics according to the change of stacking sequences and curvature radius in the composite laminated shell. They are staked to [02/902]S and [0/902/0]s, their interlaminar number are two and four. We are manufactured to composite laminated shells with various curvature radius. Curvature radius of composite shell is 100, 150, 200mm and ∞(it's meaning flat-plate). In general, kinetic energy after impact-kinetic energy before impact increased linearly in all specimens. Absorbed energy increased linearly as the curvature increased, and absorbed energy of [02/902]S specimen, which is small interlaminar number, was higher than [0/902/0]s specimen.

본 연구는 공동주택단지 용적률변화에 따른 녹지면적 및 녹지구조의 변화파악을 목적으로 수행하였다. 대상지는 용적률 100%이하, 용적률 250%이하, 용적률 250%이상의 세 유형으로 구분하여 각 유형별로 2개소씩 선정하였다. 1970～1980년에 조성한 용적률 99%인 화곡제2주공아파트와 용적률 73%인 개포주공아파트는 녹지면적 비율 40.23～44.23%, 녹지 폭 3～ 15m 녹지 량 1.06～1.71㎥／m2, 교목층 식재밀도 0.04～0.06주／m2 관목층 식재밀도 0.06 ～0.20주／m2이었다. 1990년대에 조성한 용적률 226%인 등촌주공아파트와 용적률 240%인 개화 아파트는 녹지면적비율 24 16～26.16%, 녹지폭3～7m, 녹지량 0.84～l.54㎥／m2, 교목층 식재밀도 0.18～0.31주／m2, 관목층 식재밀도0.15～0.35주／m2이었다. 1990년대말에 조성한 용적률 269%인 한보구암아파트와 용적률 376%인 동아3차아파트는 녹지면적비율 23.47～25.53%, 녹지폭 2～6m, 녹지량1.06～2.12㎥／m2, 교목층 식재밀도 0.25주／m2, 관목층 식재밀도 0.22～0.37주／m2이었다. 용적률변화에 따른 녹지구조 분석결과 녹지면적은 용적률이 높을수록 넓었으나, 녹지량과 식재밀도는 용적률의 변화와 상관없이 전체적으로 낮은 상태이었고 식재구조는 외래종위주의 단층구조이었다.

꿈의 암치료기라고 불리는 중입자 치료는 환자의 암세포에 입사하여 암세포만을 사멸하고 사라지는데 이때 중성자 및 감마선이 발생되어 치료실 내 영상장비, 그 밖의 전자장비에 영향을 미치게 된다. 중입자 치료시설을 구축하기 위해서는 약 2,000억 원 가량의 예산이 필요하며 구축기간도 5년 이상 소요된다. 따 라서 구축 전 몬테카를로 시뮬레이션을 이용하여 치료실 내 선량 분포에 대해 관찰하여 적절한 대비를 하 는 것이 중요하다. 본 연구에서는 몬테카를로 시뮬레이션 툴인 FLUKA를 이용하여 중입자 치료 시 치료실 내 선량분포에 대해 알아보았으며 1분 치료 시 치료실 내에는 약 0.1 mSv에서 2 pSv 정도의 영향이 있을 것으로 파악되었다.

In this paper, the length change of mortar substituted the crushed heavy weight waste glass as fine aggregate are evaluated. From the results, when waste glass substitution ratio increase, ASR expansion increase. However, the dry shrinkage decrease. So, the length change of mortar are significantly affected by waste glass substitution ratio.

In this study, four reinforced concrete beams, replacing recycled coarse aggregate with PVA fiber(BSPG-R series), were constructed and tested under monotonic loading. Experimental programs were carried out to improve and evaluate the structural performance of such test specimens, such as the load-displacement, the failure mode and the maximum load carrying capacity. all the specimens were modeled in 1/2 scale-down size.

This study has cross checked the change of internal sludge-recycle in Anaerobic-Digestion, and researched about not only the improvement of Bio-gas production from the digested sludge but also the efficient method of sludge minimization. Ultimate object of the study is to reduce the amount of sludge by the improved efficiency of contact with the organic-matter and the microbes in Anaerobic-Digestion. The sludge-recycle fluidized sludge layer and raised the activity of the sludge, the optimal sludge-recycle ratio, VS and COD removal ratio were 1,000%, 28.2% and 27.7%, respectively. Through these results of this study, it may be of use to treat waste sludge by the sludge-recycle ratio in terms of minimization and circulation of resources.

The monthly variations of blood characteristics and RNA/DNA of black sea bream, Acanthopagrus schlegeli, habituated in Geojae costal area were analysed to determine health condition of natural stocks in terms of gonad maturation and spawning season from March 2010 to February 2011. Spawning season determinated by gonadosomatic index is from June to August. RNA/DNA ratio of black sea bream muscle was strongly correlated with spawning season. During the gonad maturation RNA/DNA ratio in dorsal muscle tissue was decreased contrast to rapid increase during spawning season. Blood composition factors increased in terms of gonad maturation are aspartate aminotransferase, cholesterol, triglyceride, total protein, glucose, globulin, alkaline phosphatase and inorganic phosphate. Other blood factors increased during spawning season are alanine aminotransferase, blood urea nitrogen, uric acid and lactate dehydrogenase.

기후변화에 따른 지역적 영향인 기온 상승과 강수량 변화로 인한 수자원 변화 특성을 파악하기 위하여 기상청(KMA)으로부터 전국 59개 관측지점에 대해서 1973년부터 2009년까지 강수량 및 기온자료를 이용하여 산정한 강수효율자료와 국가수자원관리종합시스템(WAMIS)으로부터 1966년부터 2007년까지 PRMS 모의 유출량 자료를 수집, 분석하였다. 분석결과, 전반적으로 강수효율의 거동은 강수량의 변화 특성을 따르나 지역적으로 강수량이 증가함에도 불구하

본 연구는 다양한 옥상의 환경조건을 감안해 볼 때 지속적인 생장과 생존이 가능한 범위 내의 토양 토심 및 토양배합비에 따른 토양수분변화를 검토함으로써 현재 일률적으로 규정되어 있는 토심을 줄여 하중을 줄이고, 최소한의 관수만으로도 적정수준의 생육에 필요한 토양층 조성을 도출하고자 하였다. 또한 순비기나무 생육에 효과적인 관리방법과 토양조건의 조합형을 탐색제안함으로써 설계 및 시공관리기술의 개발에 필요한 기초자료와 정책에 반영할 수 있는 방안을 모색하고자 하며, 다음과 같은 결론을 얻었다. 대체적으로 모든 실험구에서 토양수분함량이 점점 감소하는 경향을 보이다가 관수를 포함한 강우 시 수분함량이 올라갔으며, S10, S7L3, S5L5 실험구의 경우에는 강우 후 수분함량이 급격히 떨어지는 경향을 나타내었다. 이에 비해 피트모스와 펄라이트가 포함된 P7P1L2, P6P2L2, P5P3L2, P4P4L2 실험구는 완만하게 감소하여 저관리를 위한 옥상에서의 인공토양 사용은 불가피할 것으로 판단된다. 인공토양을 이용한 적정토심 및 토양 배합비는 관수시점 및 강우와 밀접한 관련이 있다고 판단되며, 7㎝ 토심의 경우 잦은 수분관리가 필요할 것으로 판단된다. 15㎝ 실험구의 14일 무관수에서도 충분히 순비기나무가 생육한 점과 P6P2L2 이상의 피트모스 배합비에서 왕성한 생육이 이루어진 점에서 미루어 볼 때 15일 이상의 저관리에 필요한 인공토양의 배합비는 펄라이트 피트모스 부엽토가 6:2:2, 5:3:2, 4:4:2가 될 것으로 판단된다. 다만, 펄라이트가 많이 배합된 토양에서는 토양이 물을 흡입하는 힘인 토양수분장력(kPa)이 높은 수치로 올라가 추후 순비기나무가 활발히 성장할 수 있는 수분장력의 범위를 설정하는데 연구가 지속되어야 할 것이다. 토심 및 토양배합비에 따른 순비기나무의 광합성특성을 살펴보면 수분함량이 적은 7㎝ 실험구에서는 거의 이루어지지 않았으며, 15cm나 25㎝ 실험구 중 인공토양이 배합된 곳에서 활발하게 이루어진 것으로 나타났다. 또한 통계적으로 살펴볼 때 수분함량이 1%씩 증가할 때 광합성률은 2.82%씩 증가하는 것으로 나타났으며 99%의 유의수준을 보였다. 추후 연구에서는 순비기나무의 생육에 필요한 최소한의 수분함량을 판단하고 그에 따른 토양토심별 적정 관수시점을 찾아내 저관리 옥상녹화와 더불어 식물소재 개발에 이바지 하고자 한다. 또한 순비기나무 이외에 옥상녹화에 적합한 목본을 선정하고, 도시열섬현상 완화 효과를 규명하며, 이를 바탕으로 우리나라 중부지역에 알맞은 저관리형 옥상녹화시스템을 구축하고자 하는 연구가 진행되어야 할 것이다.