• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.688-694
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• 2009

As a drive system for next generation train, we have been making research and development of a direct drive traction motor system without the conventional reduction gear. This traction motor is expected to have many advantages such as low noise, reduced maintenance, and energy saving. Due to the demand for high-output motors in the limited space between the wheels, open-ventilating traction motors with gear box have been widely used for many years. However, a conventional open-ventilating traction motor is necessary periodical disassembly to remove the accumulated dust from open-air ventilation. Reducing this burden, as well as increasing energy efficiency and reducing noise, would benefit the next generation of traction motors. To address these needs, KRRI have been developing a fully enclosed type direct drive motor(DDM) with high-efficiency permanent magnet for the next generation train.

• 한국축산시설환경학회지
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• 제5권3호
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• pp.203-216
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• 1999

Recent public concern about air pollution caused by swine production facilities has forced to develop the methods to reduce and control the swine odors. Swine odors were affected the life of pig farm neighborhoods, swine productivity, pig health, diseases, and human right, safety, sanity as negatively. The first approaches of control of swine odors are the change or improve of the classical management systems, which are manure treatment method, manure storage facility, phase feeding, sex-divided feeding, feeder type, liquid-slurry feeding, environment control of swine building and dust control of indoor swine facility. The methods to control odor emission from manure have to include the diet modification as nutritional basis. In recent, research emphasis has focused on manipulating the swine diet to increase the nutrient utilization of the diet to reduce excretion products and reduction of odors. There are lots of feed additives and pit additives introduced as practical basis for reducing odor emissions. The ozone treatment method is candidate as the good system for reducing swine odor. But this system is still too expensive to practice in present.

• 한국농공학회논문집
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• 제63권5호
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• pp.63-71
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• 2021

Windbreak forests, which have a windproof effect against strong winds, are known to be effective in reducing the spread of odors and dust emitted from livestock farms. The effect of reducing the spread of odors and dust can be estimated through numerical models such as computational fluid dynamics, which require aerodynamic coefficients of the windbreaks for accurate prediction of their performance. In this study, we aimed to evaluate the aerodynamic coefficients, Co, C₁, C₂, and α, of two windbreaks, Thuja occidentalis and a mesh net, through wind tunnel experiments. The aerodynamic coefficients were derived by the relation between the incoming wind speed and the pressure loss due to the windbreaks which was measured by differential pressure sensors. In order to estimate the change in the aerodynamic coefficient concerning various leaf density, the experiments were conducted repeatedly by removing the leaves gradually in various stages. The results showed that the power law regression model more suitable for coefficient evaluation compared to the Darcy-Forchheimer model.

• 산경연구논집
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• 제10권1호
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• pp.9-17
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• 2019

Purpose - Urban agglomeration construction is one of national strategic plans to accelerate the development of industrialization and urbanization in China, which has threatened the eco-environmental quality at the same time. This paper selected the urban agglomeration in the middle reaches of the Yangtze River as the research area. Research design, data, and methodology - The the slack-based measurement (SBM) model considering undesirable outputs is applied to measure the eco-efficiency of this urban agglomerations during 2006-2015. Results - The empirical results show that average eco-efficiency of the urban agglomeration in the middle reaches of the Yangtze River is 0.595. Regional ecological development is unbalanced. The highest eco-efficiency is recorded at Wuhan Metropolitan Area, and the lowest one is at the Changsha-Zhuzhou-Xiangtan City Group. Energy consumption and waste dust emissions are the key factors led to ecological inefficiency. Based on this, potentials for energy saving and waste dust reducing are calculated. Conclusions - Finally, this study provides policy implications targeted to promote the coordinating development of economy and eco-environment under the construction of urban agglomeration.

• 천문학회보
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• 제37권1호
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• pp.38.2-38.2
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• 2012

We use two-dimensional high-resolution MHD simulations to investigate the effects of magnetic fields on the formation and evolution of such substructures as well as on the mass inflow rates to the galaxy center. We find that there exists an outermost x1-orbit relative to which gaseous responses to an imposed stellar bar potential are completely different between inside and outside. Inside this orbit, gas is shocked into dust lanes and infalls to form a nuclear ring. Magnetic fields are compressed in dust lanes, reducing their peak density. Magnetic stress removes further angular momentum of the gas at the shocks and leads to a smaller and more centrally distributed ring, resulting in the mass inflow rates larger, by more than two orders of magnitude, than in the unmagnetized counterparts. Outside the outermost x1-orbit, on the other hand, an MHD dynamo operates near the corotation and bar-end regions, efficiently amplifying magnetic fields. The amplified fields shape into trailing magnetic arms with strong fields and low density. The base of the magnetic arms have a thin layer in which magnetic fields with opposite polarity reconnect via a tearing-mode instability. This produces numerous magnetic islands with large density which propagate along the arms to turn the outer disk into a highly chaotic state.

• 한국기계가공학회지
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• 제19권1호
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• pp.29-35
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• 2020

Car inspection systems are regularly carried out by the state to ensure the safety and emission status of cars, thereby improving the safety and quality of life by reducing fine dust and greenhouse gases that are the main culprits of vehicle defects and air pollution. These automobile inspections are largely divided into either regular or comprehensive inspections. This study analyzed the smoke measuring probes used in the lug - down 3 mode. In the previously issued paper "Improvement of Soot Probe Efficiency for Automotive Emission Measurement," an improved smoke measurement probe(B) improved on the problems that arise from the current smoke measurement probe (A). In this study, a technique that can improve the probe's inhalation efficiency over the improved (B) probes was applied to probes (C). Probe (C) involves a structure designed close to the center of the circumference of the exhaust pipe, and the suction efficiency was improved by adding a variable center unit.

• 보건의료산업학회지
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• 제6권4호
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• pp.191-204
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• 2012

The purpose of this study was to provide basic data necessary for improvement by closely examining factors of having influence upon dental technicians' turnover. Questionnaire survey was conducted of 204 dental technicians who work at dental hospitals, clinics and dental laboratory rooms in Daegu area. The following conclusions were obtained. The satisfaction with job was high in job position in more than co-representative, in the whole and other task, and in less than 9 hours as for working hours. In the satisfaction with working environment, dissatisfaction was high in women, in the working career with 7~9 years, in chief level as for the job position in charge, in being responsible for porcelain in case of the duty field, and in more than 10 people as for the number of employees. The higher satisfaction with job satisfaction and working environment led to the lower turnover intention. Turnover intention was low in case of having ventilation fan & dust collector desk and in case of being well ventilated inside the workshop. As the above results, it is considered to be necessary for arranging institutional device of protecting dental technicians' health and reducing turnover through improving working environment such as forming comfortable environment of using the dust-collecting facilities and the ventilation facilities, wearing suitable individual protective gear and arranging the rest space.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.189-190
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• 2020

The importance of indoor air quality management has recently been highlighted due to environmental problems such as indoor air pollution. Among indoor air pollutants, carbon dioxide occurs in cooking, heating, burning, and causes forgetfulness, dementia and amnesia. Radon, which occurs in building materials, soil and ground, is a type 1 carcinogen that causes lung cancer in the body through breathing. These substances can be released from the room through ventilation, but there is a limit to reducing the amount of indoor activity due to reduced ventilation conditions due to increased indoor activity time. However, these substances can be removed from the gas by adsorption. The purpose of this study was to identify the properties of granular active and powdered active white soil and mix them to make cement-based active white soil adsorbent matrix for carbon dioxide, fine dust and radon gas adsorption, and to evaluate indoor air improvements according to the mixing scale. The results of the experiment showed that active carbon dioxide adsorption performance increased for carbon dioxide and radon as the exchange rate increased through physical adsorption. In particular, the higher the replacement rate of the granular active bag, the better adsorption performance was shown.

• 한국안전학회지
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• 제30권4호
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• pp.128-134
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• 2015

The number of schools which have passed 30 years after the construction takes up 30% (5% falling to class D and E) in Korea. So, the offices of education across the nation conduct large works for the expansion, improvement and renovation of the school. But as the work takes a lot of time, the work is also conducted while the students are studying at the schools. The work at the school causes the noise, dust, vibration as the school often has the reinforced concrete structure. So, as the windows are closed to prevent the nuisance from hampering the education, the problems related to the illumination, ventilation, and control of humidity and temperature are give damages to students studying the school buildings. Actually, as the current renovation or expansion is conducted across the nation due to the implementation of the new education system and the resulting integration and construction of hub school, specialized school, meister school and it causes a lot of nuisance to the learning students and others, there are a lot of complaints from concerned people. Accordingly this study suggests the method of evaluating the factors which affect the learning environment such as the noise, dust or fine dust and reducing the nuisances to the level proper for the learning environment when the existing school is expanded, improved or renovated.

• 터널과지하공간
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• 제26권5호
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• pp.441-453
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• 2016

본 연구에서는 분진을 저감시킬 수 있고 균질한 품질을 확보하는 데 적합한 2성분 박층 뿜칠 라이너(TSL)를 개발하고 그 성능을 평가하였다. 2성분 TSL 시작품의 인장강도는 분말 1성분 TSL보다 다소 낮게 나타났으나, 높은 연성으로 인해 파괴 시의 신장률이 크게 측정되었다. 이외에도 EFNARC(2008)에서 제시하고 있는 성능기준들을 만족하였으며, 두께 3 mm로 피복한 코팅 압축시험 결과, 재령 28일의 평균 압축강도가 50% 이상 향상되는 것으로 확인되었다. 시험타설을 통해 본 연구에서 개발된 2성분 TSL 시작품에 적합한 타설장비를 도출하였으며, 실제 현장시공을 통해 2성분 TSL 타설 시의 분진과 리바운드가 극히 미미함을 확인하였다. 2성분 TSL의 타설속도는 $60m^2/hr$이었으며 일반적인 뿜칠 방수 멤브레인과 비교할 때 빠른 경화 특성을 나타내었다.