• 한국환경과학회지
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• 제12권10호
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• pp.1043-1054
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• 2003

During the period from April to September 2002, the size distributions of ambient aerosol were measured at the coastal site at Hamduk in Jeju Island. Na$\^$+/, K$\^$+/, Mg$\^$2+/, Ca$\^$2+/and Cl$\^$-/ exhibited mostly a bimodal coarse mode size distribution, while ammonium and sulfate were mainly in the fine size range, with maximum at around 0.54$\mu\textrm{m}$. The average molar concentration ratio of ammonium to sulfate for fine particles was equal to 2.0${\pm}$0.9. Nitrate was evenly found in both the coarse and fine modes. Elements like Al, Fe, Cu, Mg, Na, Ti, Sr and Mn were dominant in coarse particles, with the maximum at around 5.25$\mu\textrm{m}$. S and Pb were mainly in the submicrometer size range. Other elements with a fine and coarse modes were V, Ni, Cu, Ba and Mo. The patterns of the size distributions of trace elements measured at the downtown in Jeju City were very similar to those at the coastal site in Hamduk. However, the amplitude of size fractional concentrations at Jeju City was narrower than that at Hamduk. While the mass median diameters for the chemical species originated from the natural origin such as marine and crust were relatively large, those for ammonium, sulfate, S and Pb were very small.

• 한국재료학회지
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• 제29권4호
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• pp.264-270
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• 2019

As a case study on aspect ratio behavior, Kaolin, zeolite, $TiO_2$, pozzolan and diatomaceous earth minerals are investigated using wet milling with 0.3 pai media. The grinding process using small media of 0.3 pai is suitable for current work processing applications. Primary particles with average particle size distribution D50, ${\sim}6{\mu}m$ are shifted to submicron size, D50 ${\sim}0.6{\mu}m$, after grinding. Grinding of particles is characterized by various size parameters such as sphericity as geometric shape, equivalent diameter, and average particle size distribution. Herein, we systematically provide an overview of factors affecting the primary particle size reduction. Energy consumption for grinding is determined using classical grinding laws, including Rittinger's and Kick's laws. Submicron size is obtained at maximum frictional shear stress. Alterations in properties of wettability, heat resistance, thermal conductivity, and adhesion increase with increasing particle surface area. In the comparison of the aspect ratio of the submicron powder, the air heat conductivity and the total heat release amount increase 68 % and 2 times, respectively.

• 대기
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• 제25권3호
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• pp.569-573
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• 2015

An algorithm to symmetric radius of $15ms^{-1}$ isotaches of tropical cyclones is suggested using infrared (IR) imagery of geostationary satellite. It is assumed that symmetric tangential winds outside the maximum winds exponentially decrease with the radial distances of the tropical cyclone, which has a clear eye-wall structure. Four parameters for estimation of the tropical cyclone size are center location, maximum sustained wind, radius of the maximum wind, and relaxation coefficient for the decreasing rate with distances of the tropical cyclone. The estimation results are limitedly verified as comparing to surface winds of polar orbiting satellite such as ASCAT data.

• Journal of the Korean Data and Information Science Society
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• 제15권2호
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• pp.467-476
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• 2004

Recently, an approximation of a wavelet series has been developed in the analyses of an unknown function. Most of articles have been studied on thresholding and shrinkage methods for its wavelet coefficients based on (non)parametric and Bayesian methods when the sample size is considered as a maximum resolution in wavelet series. In this paper, regardless of the sample size, we are focusing only on the choice of a maximum resolution in wavelet series. We propose a Bayesian approach to the choice of a maximum resolution based on the linear combination of the wavelet basis functions.

• 한국자동차공학회논문집
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• 제7권5호
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• pp.221-229
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• 1999

We examined the governing factors of fatigue limit in annealed and austempered ductile iron specimens machined micro hole(dia.<0.4mm) in rotary bending fatigue test. Also, the quantitative relationship between fatigue limit and maximum defect size in specimens was investigated. Artificial defect(micro-pit type, dia.<0.4mm) on specimen surface did not bring about an obvious reduction of fatigue limit in austempered ductile iton(ADI) as compared with annealed ductile iron. According to the investigation of ${\sqrt{area}}_c$ which is the critical defect size to crack initiation at artificial defect, ${\sqrt{area}}_c$ of ADI was larger than that of annealed ductile iron. This shows that the situation of crack initiation at artificial defect in ADI is more difficult in comparison with annealed ductile iron. Maximum defect size is one of the important parameters to predict fatigue limit. And, the quantitative relationship, between the fatigue limit ${\sigma}_{\omega}$ and the maximum defect size ${\sqrt{area}}_{max}$ can be expressed to ${\sigma}_{\omega}^n{\cdot}{\sqrt{area}}_{max}=C_2$ where, $C_2$ are constant. Moreover, it is possible to explain the difference in fatigue limit between, austempered and annealed ductile iron by introducing the parameter ${\delta}(=N_{sg}/N_{total})$in a plain spectimen.

• 한국의류학회지
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• 제41권4호
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• pp.752-770
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• 2017

This study provides a size specification and ease for the development of pants for working clothes in the construction industry according to season. We collected and measured the size specification of 4 types of Spring/Fall pants, 4 types of winter brushed bonding pants, and 4 types of winter padded pants. Subjective comfort evaluation and analysis of ease sensation were performed for all products on 12 subjects. The average size specifications for the pants according to seasons were as follows. Spring/Fall pants had 74.0/80.0cm waist size (relaxed/maximum stretched) and 104.0cm hip size. Winter brushed bonding pants had 76.0/83.4cm for waist size and 106.0cm for hip size. Winter padded pants had 71.5/84.0cm for waist size and 112.8cm for hip size. When designing a pattern by comparing product size specification and subject body size, the recommended ease is 0.2/7.2cm for waist size (relaxed, maximum stretched) and 13.6cm for hip size for Spring/Fall pants, and 0.2/6.2cm for waist size and 11.6cm for hip size of winter brushed bonding pants, and -5.3/7.2cm for waist size and 19.4cm for the hip size of winter padded pants.

• 한국컴퓨터정보학회논문지
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• 제14권1호
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• pp.65-72
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• 2009

본 연구는 주어진 부피제약조건 하에서 최대강성을 구현하는 고층 철골 트러스 시스템의 단면치수 재조정 프로세스를 보여준다. 이러한 치수최적설계는 경사도법에 근거한 최적정 방법에 의해 수치적으로 연산된다. 전형적인 치수최적설계에서는 변위나 응력제약조건 하에서 구조물의 최소중량을 구현하지만, 본 연구에서 소개되는 치수최적설계는 이것과 반대의 프로세스를 가진다. 즉, 부피와 같은 재료제약조건 하에서 최대강성을 구현한다. 본 연구는 기존의 치수최적설계방법의 대안으로서 그 의미를 가질 수 있다. 고층 철골트러스 구조시스템의 수치 예제를 통하여 부재 단면치수 재조정 설계가 기존의 최소중량설계와 반대인 최대강성 이산화 치수최적설계를 통하여 적합하게 수행됨이 증명되었다.

• Journal of Plant Biotechnology
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• 제6권4호
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• pp.265-268
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• 2004

Cell growth and ginseng saponin production by large-scale suspension (bioreactor) cultures of Panax ginseng were investigated under various inoculum sizes. Cell growth was low at an inoculum size of 40 g FW/L, and the maximum cell growth was obtained with increasing inoculum size up to 100 g FW/L. The cell density of 333 g FW/L and 12.7 g DW/L was obtained at inoculum size of 100 g FW/L after 30 days of cultivation. Maximum saponin production of $4.40\;\cal{mg/g}$ DW was achieved at 60 g FW/L of inoculum size. Thus, inoculum size 60 g FW/L was suitable for optimum biomass accumulation as well as saponin production during bioreactor cultivation of ginseng suspension cells.

• 한국인터넷방송통신학회논문지
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• 제16권1호
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• pp.109-114
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• 2016

본 논문은 디지털 무선 전송시 채널에서 발생되는 부호간 간섭과 잡음의 영향을 최소화하기 위한 CCA (Compact Constellation Algorithm) 등화 알고리즘에서 적응 스텝 크기를 적용하여 이의 등화 성능 개선에 관한 것이다. 일반적으로 등화 알고리즘에서 적응을 위한 스텝 크기는 고정적으로 사용하지만, 제안 알고리즘에서는 등화를 위한 스텝 크기를 비선형 함수인 오차 신호에 비례하도록 변화시킨다. 이의 개선된 등화 성능을 보이기 위하여 등화기 출력 성상도, 잔류 isi, 최대 찌그러짐과 MSE와 SER을 적용하였으며, 이들을 고정 스텝 크기를 갖는 기존 CCA와 비교하였다. 컴퓨터 시뮬레이션의 결과 정상 상태 이후에서는 적응 스텝 방식의 CCA가 고정 스텝 방식의 CCA보다 우월함을 확인하였다.

• 한국대기환경학회지
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• 제4권2호
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• pp.28-37
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• 1988

Light scattering coefficient of visible light by atmospheric aerosol over the size range 0.01-10$\mu$m is determined from scattering efficiency and aerosol size distribution. Aerosol number distribution as a function of particle diameter dN/dlog D decreases rapidly as increasing particle size. Distribution of scattering coefficient d$\sigma_s/dlog$ D is mostly accumulated in diameter 0.1-2.0 $\mu$m showing its maximum in the vicinity of 0.6$\mu$m. This means that the visible light in the atmosphere is mainly scattered by these particles. Diurnal variation of scattering coefficient $\sigma_s$ appears its maximum in the morning, while minimum in the afternoon which agrees with the aerosol number distribution in the size range 0.1-2.0 $\mu$m.