• Fibers and Polymers
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• 제4권4호
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• pp.145-150
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• 2003

Polypropylene nonwoven fabrics were exposed to He/$O_2$ atmospheric pressure glow discharge plasma. Surface chemical analysis and contact angle measurement revealed the surface oxidation by formation of new functional groups after plasma treatment. Weight loss (%) measurement and scanning electron microscopy analysis showed a significant plasma etching effect. It was investigated in low-stress mechanical properties of the fabrics using Kawabata Evaluation System (KES-FB). The surface morphology change by plasma treatment increased surface friction due to an enhancement of fiber-to-fiber friction, resulting in change of other low-stress mechanical properties of fabric.

• 한국대기환경학회지
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• 제11권2호
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• pp.145-152
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• 1995

Predictability of a Gaussian model, ISCST2 was assessed by scaling up wind tunnel experiments with a 1/3,000 terrain model to the real scale. Concentration profiles obtained from the flat-terrain experiment in the neutral condition were estimated to be in agreement with the calculated ones from ISCST2 in the stability class A, but the difference between the two was still large. Concentration profiles from the mountainous-terrain experiments were better fitted to the calculated ones primarily because in the experiment, concentration behind the source was raised due to the effect of a hill in the upstream side. Model prediction was improved with including the downwash effect of buildings and the hill, but overall concentration profiles were not much different from a typical Gaussian profile. While concentration profiles in the experiments were changed with local flows by varying the wind direction and the topography, those from the Gaussian modeling were mot freely changed together with these variations.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.560-564
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• 1996

In recently, annealing process of cold rolled sheet tend to change to continuous annealing process for improving qualify, saving yield. In the meantime as demand for various kind and small lot of products has been increasing, batch annealing has been appreciated for its small restriction for the operation. So, we tested on the effect for a hydrogen contents of atmospheric gas at annealing furnace. As a result of several investigation. We confirmed for the following characteristics ; improved productivity, uniform heating, improved surface quality, saving energy. Therefore, the use of hydrogen instead of nitrogen as the protective gas, combined with high convection in batch annealing furnaces, has shown that considerable increases in furnace output and material quality are attainable. Owing to the low density, high diffusion and reducing character of hydrogen, a better transfer resulting in uniform material temperatures and improved coil surfaces can be achieved.

• Journal of Positioning, Navigation, and Timing
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• 제10권1호
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• pp.29-34
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• 2021

Recently, many studies have considered the effect of atmospheric pressure loading (APL) on precise global navigation satellite system (GNSS) data processing. The APL deforms the Earth's crust. It can often exceed 10 mm in radial displacement. In this study, we analyze the APL effect on Multi-GNSS kinematic precise point positioning (PPP). In addition, observations received at two GNSS reference stations (DAEJ and SUWN) in South Korea were processed. The absolute position changes for the two stations were compared to before and after applying the APL effects from January 1 to February 29, 2020. The crust of South Korea was most affected by the APL in the up direction. With the APL model, the difference in daily position changes was mostly within 4 mm in the radial direction. On the other hand, the horizontal components (east-west and north-south) were relatively less affected than the radial component.

• 대한원격탐사학회지
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• 제35권6_1호
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• pp.1011-1030
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• 2019

인공위성 또는 항공기에서 사용되는 원격탐사용 센서는 지구 대기를 통과하는 전자기파를 측정하므로, 지구 대기에 의하여 흡수 또는 산란되는 과정에서 지표면의 정보가 영향을 받게 된다. 인공위성은 탑재센서의 사용목적에 따라 파장범위, 해상도가 다르지만, 공통적으로 지구 표면의 대상의 분광신호를 정확히 측정하기 위하여 대기에 의한 영향을 제거해야 하는 대기보정이 이루어져야 한다. 대기보정의 목적은 원격탐사 영상에서 대기 효과를 제거하여 지표면 반사도 값을 결정하고 지표면의 물리적 매개 변수를 도출하는 것이다. 현재까지 개발된 대기보정 알고리즘은 영상기반의 경험적인 방법 또는 현지 관측 자료를 이용한 간접적인 보정 방법에서 보다 복잡한 복사전달과정을 수치해석적으로 해석하는 직접적인 보정 방법으로 발전해 왔다. 본 연구는 지난 40여년 동안 개발된 대기보정 알고리즘에 대한 연구 기록을 분석함으로써, 대기보정 기술의 현황 및 주요 대기보정 알고리즘에 대한 연구 결과를 체계적으로 정립하여 관련 기술의 현황 및 연구동향을 제시하였다.

• 한국입자에어로졸학회지
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• 제10권2호
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• pp.75-82
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• 2014

It is necessary to find out the reaction characteristics of $CaCO_3$ sorbent particles in air and $O_2/CO_2$ atmospheric conditions in order that an in-furnace desulfurization technique can be applied to oxy-fuel combustion system. In this study, rate of change of GMD(geometric mean diameter) and specific surface area of $CaCO_3$ sorbent particles reacted in DTF(drop tube furnace) experimental setup were analyzed to investigate the effect of particle size and humidity on the reaction characteristics of them. In air atmospheric condition, calcination process occurs actively within shorter residence times as the particle size increases. On the contrary, in $O_2/CO_2$ atmospheric condition, a calcination process is delayed as particle size increases. The increment of humidity accelerates calcination process in an air atmospheric condition and increase rate of calcination in an $O_2/CO_2$ atmospheric condition.

• 대기
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• 제27권1호
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• pp.93-104
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• 2017

The effect of Advanced Microwave Sounding Unit-A (AMSU-A) observations on the short-range forecast in East Asia (EA) was investigated for the Northern Hemispheric (NH) summer and winter months, using the Forecast Sensitivity to Observations (FSO) method. For both periods, the contribution of radiosonde (TEMP) to the EA forecast was largest, followed by AIRCRAFT, AMSU-A, Infrared Atmospheric Sounding Interferometer (IASI), and the atmospheric motion vector of Communication, Ocean and Meteorological Satellite (COMS) or Multi-functional Transport Satellite (MTSAT). The contribution of AMSU-A sensor was largely originated from the NOAA 19, NOAA 18, and MetOp-A (NOAA 19 and 18) satellites in the NH summer (winter). The contribution of AMSU-A sensor on the MetOp-A (NOAA 18 and 19) satellites was large at 00 and 12 UTC (06 and 18 UTC) analysis times, which was associated with the scanning track of four satellites. The MetOp-A provided the radiance data over the Korea Peninsula in the morning (08:00~11:30 LST), which was important to the morning forecast. In the NH summer, the channel 5 observations on MetOp-A, NOAA 18, 19 along the seaside (along the ridge of the subtropical high) increased (decreased) the forecast error slightly (largely). In the NH winter, the channel 8 observations on NOAA 18 (NOAA 15 and MetOp-A) over the Eastern China (Tibetan Plateau) decreased (increased) the forecast error. The FSO provides useful information on the effect of each AMSU-A sensor on the EA forecasts, which leads guidance to better use of AMSU-A observations for EA regional numerical weather prediction.

• 한국지구과학회지
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• 제21권4호
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• pp.369-379
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• 2000

이 연구의 목적은 대기압에 대하여 전통적 수업모형과 인지갈등을 이용한 수업모형을 적용하여 수업 전과 수업 2주후, 수업 3개월 후의 개념 변화를 분석하고 그에 따른 학습 효과를 알아보는 데 있다. 이 연구의 대상은 184명이며 통제집단과 실험집단으로 구분하여 수업 전 개념이해 유형을 파악하고 전통적 수업모형과 인지 갈등 수업모형을 적용하여 학습 한 후 개념변화를 분석하였다. 이 연구의 결과는 다음과 같다. 1) 수업 전에는 대기압과 관련된 기초개념에 대한 이해수준이 낮았으나 일상생활과 관련된 경험적이거나 암기적 개념에서는 비교적 이해수준이 높게 나타났다. 2) 인지갈등 수업모형을 이용한 수업 후의 개념 변화는 전통적 수업모형에 비해 과학적 개념 형성에 학습 효과가 높은 것으로 나타났으며 3) 문항에 따라 다소 차이는 있지만 수업 3개월 후 개념의 지속성 측면에서도 인지 갈등을 이용한 수업모형이 전통적 수업모형보다 효과적인 것으로 분석되었다.

• 한국대기환경학회지
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• 제21권2호
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• pp.243-257
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• 2005

The effects of Traffic Control Program (TCP) on the ambient urban air quality of SO$_{2}$, NO$_{2}$, O$_{3}$, and PM$_{10}$ were evaluated in Seoul metropolitan area by using the lower atmospheric vertical stability index and daily mean wind speeds. The vertical stability index; temperature lapse rate between 1000 hPa and 850 hPa geopotential height fields, were used to identify daily vertical stability index during the 2002 World Cup period where traffic amount was reportedly reduced to half the number of vehicles. The indicated air quality levels of TCP days were then compared with those of the cases observed with analogous vertical stability during the recent 3 years from 2000 to 2002. The result indicates that the effect of TCP on the primary air pollutants are found to be approximately 39$\%$, 23$\%$ and 20$\%$ lower for SO$_{2}$, NO$_{2}$ and PM$_{10}$, respectively. The secondary air pollutant; ozone, showed relatively smaller decreasing rate (13$\%$) of daily mean concentrations (even increased during the night time). The comparison of daily maximum or peak concentrations reveals that the pronounced decreasing effects of TCP on the ambient air quality for both primary and secondary air pollutants, suggesting that TCP is one of the effective strategies to control peak or higher concentrations for most urban scale air pollutants in and around the Seoul metropolitan area.

• 한국지구과학회지
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• 제25권4호
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• pp.214-221
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• 2004

본 연구에서는 현행 제7차 교육과정의 중학교 과학교과에서 제시된 대기압 개념을 분석하여 무게의 측면으로 대기압을 설명하는 교과서를 이용한 수업(수업방안 A)과 기체 분자운동과 무게의 양쪽 측면에서 설명하는 교과서를 이용한 수업(수업방안 B)의 두 가지 수업방안을 선정한 후 수업방안이 중학생들의 대기압 개념변화에 미치는 영향에 대하여 알아보았다. 이를 위하여 중학교 3학년 4개 학급을 대상으로 2개 학급씩 나누어 각각 수업을 실시하였다. 이 때 수업 전-후에 나타나는 학업 성취도와 대기압의 개념변화를 조사해본 결과는 다음과 같다. 첫째, 학업 성취도에 미치는 효과는 '수업방안 B'가 '수업방안 A'에 비해서 효과가 있는 것으로 나타났다. 둘째, 개념변화에 미치는 효과는 개념 검사의 사후 점수를 각 하위척도별로 효과를 검증한 결과, 개념의 요소 4개 중 3개의 요소인 '대기압이 작용하는 원리'와·대기압이 작용하는 방향과 이유', '지표면의 온도 상승에 따른 기압 변화와 그 이유'에서는 개념 변화에 유의미한 향상이 있는 것으로 나타났으나 '고도에 따른 대기압의 분포와 그 이유'에서는 개념 변화에 있어 유사한 것으로 나타났다. 셋째, 대기압 개념의 올바른 수업방안으로는 대기압을 기체 분자 운동론의 입장에서 정의하고 높이에 따른 대기업의 크기 분포는 공기의 무게로 정의한 것과 결과가 같게 나타남을 강조할 필요가 있다.