• Title/Summary/Keyword: Major losses

검색결과 377건 처리시간 0.024초

미세입자(PM2.5) 측정시 발생되는 질산염(NO3-) 휘발에 관한 연구 (A Study on the Volatilization of Particulate Nitrate (NO3-) During Fine Particle (PM2.5) Measurement)

  • 강병욱;이학성
    • 한국대기환경학회지
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    • 제18권4호
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    • pp.297-303
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    • 2002
  • Fine particles (d$_{p}$ < 2.5 $\mu$m) were measured using an annular denuder system (ADS) in Chongju. The data set was collected on fifty-eight different days with a 24-hr sampling period from October 27, 1995 through August 25, 1996. Particulate nitrate in the ADS was also measured on teflon and nylon filters in series behind denuders to collect HNO$_3$, HNO$_2$, SO$_2$and NH$_3$. From this study. the mean concentration of particulate nitrate of PM$_{2.5}$ in the ADS were seen with the following order: winter (5.05) >fall (4.36) >spring (3.92) > summer (1.10 $\mu\textrm{g}$/㎥). Nitrate losses, which calculated from the ratio of nylon filter nitrate to the sum of teflon and nylon filter nitrates, varied in the following manner summer (72.2%) > spring (42.6%) > fall (23.5%)> winter (0.4%). Especially, gaseous nitric acid was dominant at temperature higher than 8$^{\circ}C$ while particulate nitrate was major species in total nitrate below that temperature. This indicates the particulate nitrate loss is strongly correlated rather with ambient temperature.e.e.

클린 디젤엔진용 워터펌프 유동해석 (Flow Analysis of Water Pump for Clean Disel Engine Application)

  • 이동주;김태영;전문수
    • 융복합기술연구소 논문집
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    • 제4권2호
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    • pp.61-65
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    • 2014
  • Pressure distribution around rotating impeller blades in centrifugal pump has been main issue for design of efficient and high performance automotive water pump. In addition, pressure losses of inlet water pipes should be considered to reduce additional pressure drop and design high performance engine cooling system. In this paper, pressure distribution inside water pump and pressure drop between inlet and outlet of water pump are investigated numerically to design plastic water pump for clean diesel engine application. And the inlet geometry of water pump was considered to analysis the effect of inlet water pipe geometry on pressure distribution around impeller blades and outlet pressure. The prediction results are compared with experimental data to validate and determine optimal operation condition without water pump cavitation. Major design parameters such as blade angle, volute geometry, system pressure, and coolant flow rate are considered to confirm applying possibility of plastic blades to the clean diesel engine.

Soluble Expression of OmpA from Haemophilus parasuis in Escherichia coli and Its Protective Effects in the Mouse Model of Infection

  • Ahn, Jungoh;Hong, Minhee;Yoo, Sungsik;Lee, Eungyo;Won, Hokeun;Yoon, Injoong;Jung, Joon-Ki;Lee, Hongweon
    • Journal of Microbiology and Biotechnology
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    • 제22권9호
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    • pp.1307-1309
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    • 2012
  • Haemophilus parasuis causes contagious porcine Gl$\ddot{a}$sser's disease leading to severe losses in the swine industry. In this study, we established an efficient Escherichia coli-based system for the expression of H. parasuis major outer-membrane protein (MOMP) that has been known as a good vaccine candidate against Gl$\ddot{a}$sser's disease. Use of an E. coli-derived pelB leader sequence made it possible to produce recombinant MOMP (rMOMP) as the soluble forms without an additional refolding process. Using two different animal models, it was evaluated that the rMOMP was capable of inducing a significant immune response and providing protection against H. parasuis infection.

산불의 공간적 확산이 농촌지역경제에 미치는 영향 분석 (Analysis of Agricultural Regional Economic Effect by Spatial Dispersal of Wildfire in Korea)

  • 권영현;김의준
    • 농촌계획
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    • 제20권3호
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    • pp.67-74
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    • 2014
  • The purpose of this study is to estimate regional economic effects of spatial diffusion of wildfire using Cobb-Douglas production function of agriculture and forestry. The analysis is applied to Gangwon and Gyeongbuk provinces where are the most damaged of wildfire in Korea. The damaged areas are derived from multiplied by the occurrence probability of wildfire and diffusion areas of wildfire for micro-spatial unit level with ArcGIS techniques. The models of wildfire provides that the spatial diffusion of wildfire increases with the rising of highest temperature and average wind speed. Through the production function, value added of Agriculture and Forest sectors get damaged where the Cos-converted slope aspect of mountains are toward the South. The production model provides reductions of regional value added by increasing damaged areas of wildfire. It reveals that the most damaged region is Andong city in Gyeongbuk province, where value added loss is 1.25 billion Won, which is about 0.72% of total value added in agriculture and forestry of the city. As a view of policy makers, it needs to be considered to establish prevention policies against wildfires because regional economic losses from wildfire are depending on geographical conditions and performances of the major industry related to wildfire's diffusion such as agriculture or tourism sector according to the result of analysis.

Aging and Scientific Performance: An Empirical Study on Korean University Researchers

  • Chung, Sungchul
    • STI Policy Review
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    • 제6권2호
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    • pp.1-23
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    • 2015
  • This study aims to contribute to the debate over the age-productivity relationships in scientific and technological research. For this purpose, we conducted an empirical experiment employing a time-series cross-section dataset derived from the KRI of the NRF containing data on individual researchers of fifty major universities in Korea covering the period of 2008-2013. This study has found that: (1) there exists an inverse U-shaped age-productivity relationship at the level of individual researchers; (2) the impact of the average age of a research group on the productivity of individual researchers varies across fields; (3) male and female researchers move along different age-productivity curves; and (4) the inverse U-shaped age-productivity relationship also holds at the level of organizations. The results suggest that the aging of researchers in Korea will soon reach the stage where serious losses in research productivity become a reality. Yet, it is not so clear whether the observed decline in the performance of older researchers is due to declining cognitive capability, which is an unavoidable result of aging, or to declining motivation, which results from an institutional system that discourages older researchers' research activities (such as reduced access to research opportunities or mandatory retirement). What is clear is that it is inevitable for the Korean science system to change the current seniority- and age-based organizational system into one of higher adaptability.

Experiences of Implementing TPM in Swedish Industries

  • Liselott Lycke;Akersten, Per-Anders
    • International Journal of Reliability and Applications
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    • 제1권1호
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    • pp.1-14
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    • 2000
  • The global marketplace is highly competitive and organisations, who want to survive long-term, have to continuously improve, change and adapt in response to market demands. These improvements should focus on cost cutting, increasing productivity levels and quality and guaranteeing deliveries in order to satisfy customers. Total Productive Maintenance (TPM) is one method, which can be used to achieve these goals. TPM is a change management approach that involves employees from both production and maintenance departments. The purpose is to eliminate major production losses by introducing a program of continuous and systematic improvements to production equipment. TPM should be developed and expanded to embrace the whole organisation and all employees should be involved in the process as members of improvement teams. This paper gives a short description of the development of TPM and the TPM implementation process. Findings are reported from a case study in which one of the authors had the possibility of following and guiding a company through their TPM implementation. The implementation process takes several years and the research has focused on the initial three years. The study demonstrates that driving forces, obstacles and difficulties often are dependent on the organisation, its managers and the individual employees.

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순창지역 메주 발효 중 미생물과 효소역가의 변화 (Changes in Microflora and Enzyme Activities of Traditional Meju during Fermentation at Sunchang Area)

  • 유진영;김현규
    • 한국식품영양과학회지
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    • 제27권3호
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    • pp.448-454
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    • 1998
  • Meju for doenjang and kochujang was prepared as a model at Sunchang areaand monitored with major changes. Kochujang meju was prepared on September 12 and doenjang meju on November 12, 1995. Kochjang meju was found to be naturally fermented at 80~90% RH, 15~2$0^{\circ}C$ and doenjang meju was at 80~90% RH and 0~5$^{\circ}C$. The shapes of kochujang meju and doenjang meju were doughnut-type and rectangular, respectively. Weight losses during fermentation were 48% and 28%, respectively. The pH drop and acip production of kochujang meju were negligible. However, pH of doenjang meju decreased from 6.29 to 5.88 and acidity increased from 0.08 to 0.23% as lactic acid. Protein in meju was found to be rapidly solubilized during the early stage of fermentation. Soluble protein cotents of kochujang meju after 7 days and 60 days were 8.23%, respectively. The doenjang mejus were 2.15% after 20 days and 5.72% after 60 days. Soluble suger content increased with the fermentation time. The soluble sugar content was higher in kochjang meju. Acidic protease was highly produced during meju fermentation. $\alpha$-Amylase and $\beta$-amylase were detected in the kochujang meju, of which glutinous rice consisted, but negligible in doenjang meju. Lipase was detected in kochujang meju, but was, negligible in doenjang meju. Microbial population increased drastically after 7 days of fermentation in kochujang meju and 20 days of fermentation in doenjang meju.

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군집화를 이용한 기업 핵심기술 유출자 분류에 관한 연구 (A Study on The Leak of Core Business Technologies Using Preventative Security Methods Such as Clustering)

  • 허승표;이대성;김귀남
    • 융합보안논문지
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    • 제10권3호
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    • pp.23-28
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    • 2010
  • 최근 국내 기업의 핵심기술 유출은 해마다 증가하고 있고 국가적인 차원에서 피해액 손실도 매년 크게 증가하고 있다. 최근 5년 간 우리나라 주요 사업의 기술유출에 따른 피해액은 220조 원에 달했고 2010년 총 예산과 비슷한 액수이다. 또한 핵심기술 유출 유형별로는 전직 직원, 현직 직원, 협력 업체 직원, 유치과학자, 투자업체 순으로 내부 인력에 의한 핵심기밀 유출이 가장 많은 것으로 나타났다. 이처럼, 사람에 의해서 핵심기밀 유출이 가장 많이 발생한 것에 따라 기업의 인원 보안 관리에 대한 대책 및 관리가 제대로 이루어 지지 않는 것을 미루어 짐작할 수 있다. 따라서 본 논문은 기업에서의 핵심기술 유출을 방지하기 위하여 내부 인력에 대한 사전 정보를 데이터 마이닝 방법을 통해서 핵심기술 유출 징후 분류 방법을 제안한다.

낙엽송(落葉松)의 종자결실(種子結實)에 영향(影響)을 미치는 요인(要因) (Factors Affecting Seed Yield in Larix)

  • 신동일;데이비드 F. 카노스키
    • 한국산림과학회지
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    • 제84권2호
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    • pp.207-217
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    • 1995
  • 4가지 낙엽송(구주낙엽송, 일본낙엽송, 시베리아낙엽송, tamarack)의 종자결실에 영향을 미치는 요인과 각각의 요인들에 의한 종자손실율을 조사하였다. 화분의 질, 수분의 실패, female gametrophyte의 퇴화 등은 종자결실에 큰 영향을 미치지 않았으나, 수정실패, 배의 퇴화 등은 조사된 4개의 수조에서 모두 주요한 종자손실요인으로 조사되었다. 조사된 요인들 중 종자수확에 가장 큰 영향을 미치는 것은 수분후 strobilus자체가 퇴화되는 것이었다. 조사된 4가지 교배조합중 구주낙엽송 또는 일본낙엽송을 모수로 하는 것이 종자생산측면에서는 가장 바람직한 것으로 나타났으며, tamarack을 모수로 하는 교배조합은 건전한 종자생산을 하지 못할 것으로 판단된다.

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중년후기 한국 어성의 노년기 전환기 경험 (Late Middle-aged Women′s Lift Experiences in Transition to Old Age : How Do They Adapt to “Aging” in Korean Society\ulcorner)

  • 강유진
    • 대한가정학회지
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    • 제42권7호
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    • pp.145-164
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    • 2004
  • The purpose of this study is to understand how late middle-aged women in our society view and adapt to “aging”. This is a crucial step forward linking two stages, the growing young age and the declining old age, which eventually improves the qualify of life in old a9e. This qualitative study used Personal narratives extracted from tape-recorded interviews of 20 late middle-aged women in their fifties and analyzed key experiences of late middle-aged women in their transition to old age. Participants were observed to perceive not only many limitations but also alternative potentialities. First, the major challenges due to the closing young era were ‘physical declines’, including health problems and wrinkles, and ‘leaving children’. Second, the potentialities to start a new era also could be found. Many participants found themselves to be generous enough to assist others in need. In addition, they looked to adapt to new challenges. It was likely that the many adversities that they had faced made them resilient. These results show that late middle-aged women were actively negotiating with themselves and their surroundings in order to overcome their losses, maintain their potentialities, and, in the process, acknowledge their impending old age for better preparation.