• 대기
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• 제30권1호
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• pp.75-89
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• 2020

Current in-situ airborne probes that measure the sizes of ice crystals smaller than 50 ㎛ are based on the concept that the measured intensity of light scattered by a particle in the forward and/or backward direction can be converted to particle size. The relationship between particle size and scattered light used in forward scattering probes is based on Mie theory, which assumes the refractive index of particle is known and all particles are spherical. Not only are small crystals not spherical, but also there are a wide variety of non-spherical shapes. Although it is well known that the scattering properties of non-spherical ice crystals differ from those of spherical shapes, the impacts of non-sphericity on derived in-situ particle size distributions are unknown. Thus, precise relationships between the intensity of scattered light and particle size and shape are required, as based on accurate calculations of scattering properties of ice crystals. In this study, single-scattering properties of ice crystals smaller than 50 ㎛ are calculated at a wavelength of 0.55 ㎛ using a numerically exact method (i.e., discrete dipole approximation). For these calculations, hexagonal ice crystals with varying aspect ratios are used to represent the shapes of natural small ice crystals to determine the errors caused by non-spherical ice crystals measured by forward scattering probes. It is shown that the calculated errors in sizing nonspherical ice crystals are at least 13% and 26% in forward (4~12°) and backward (168~176°) directions, respectively, and maximum errors are up to 120% and 132%.

• 한국철학논집
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• 제23호
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• pp.275-294
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• 2008

형신사상(形神思想)의 핵심은 인간의 육체와 영혼에 관한 문제라고 할 수 있다. 형(形)과 신(神)은 인간의 생명을 구성하고 있는 두개의 요소로 만일 그 가운데 하나라도 없다면 그것은 살아있는 인간으로 볼 수가 없다. 동진남북조(東晉南北朝) 시기의 사상가들은 '우리들을 구성하고 있는 육체와 영혼이 과연 어떻게 나온 것일까?'라는 의문으로부터 시작하여 '복잡하고 미묘한 정신작용의 본질은 과연 무엇일까?' 그리고 '육체와 영혼은 도대체 어떠한 관계에 있는 것일까?' 또한 '인간이 죽은 뒤에도 그 영혼은 존재하는 것인가 혹은 소멸되는 것인가?' 등의 문제들에 대하여 활발하게 토론과 연구를 진행했었다. 본 논문은 이러한 문제들에 대하여 다음과 같은 내용을 중심으로 분석했다. 먼저, 동진(東晉) 시기의 형신사상(形神思想)에 대하여 종병(宗炳)의 영혼은 음양(陰陽)과 같은 것으로도 헤아려지지 않는 만물 속에 있는 현묘(玄妙)한 것으로서 무시(無始) 이래 정추(精?)의 식(識)으로 나뉘어 계속 존속하는 것이라고 하는 주장. 그리고 하승천(何承天)의 무엇이든 태어나면 죽는 것이며 육체가 없어지면 영혼이 흩어지는 것은 사계절이 계속 바뀌는 것과 같다고 하면서 영혼의 존속을 부정하는 주장들을 '명불론(明佛論)'과 '달성론(達性論)'을 중심으로 당시의 담론으로 형성되었던 '신멸(神滅)'과 '신불멸(神不滅)'의 문제를 집중 분석했다. 다음으로는 남북조(南北朝) 시기의 형신사상(形神思想)에 대하여 소침(蕭琛)의 육체와 영혼은 합하기는 하지만 일체가 되는 것은 아니기 때문에 태어나면 육체와 영혼이 합하여 기능이 생겨나지만 죽으면 육체는 남고 영혼은 떠나버리나 영혼은 항존(恒存)하는 것이라는 주장. 그리고 범진(范縝)의 육체가 영혼의 질(質)이라면 영혼은 육체의 용(用)이라고 하면서 육체가 없다면 영혼 또한 없는 것이니 육체 즉 영혼이라는 주장들을 '난신멸론(難神滅論)'과 '신멸론(神滅論)'을 중심으로 하여 당시 학술계의 화두였던 '신멸(神滅)'과 '신불멸(神不滅)'의 논쟁을 집중 분석했다. 끝으로는 동진남북조(東晉南北朝) 시기에 유행하였던 형신사상(形神思想)의 의의와 그것이 중국철학사 속에서 차지하는 지위와 영향에 대하여 분석하고 조명했다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.629-632
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• 1989

The scattered light intensity from a spherical particle passing through the cross-over region of two coherent laser beams, varies periodically. Photodetection of this light beams produces a periodic signal of varying amplitude. The phase of the signal varies with the particle size and refractive index, the beam crossing angle and wavelength, and the position and size of the scattered ligth collecting aperture. In this paper the phase variation with respect to the particle absorptive index of retraction, collecting lens size and beam crossing angle is calculated using both Mie scattering theory and reflection theory. The two theories show good agreement in phase predictions, especially for large absorptive indices and for small collection lenses. Both theories predict phase to be inversely proportional to the beam crossing angle.

• 천문학논총
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• 제30권2호
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• pp.65-67
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• 2015

The surfaces of most atmosphereless solar system objects are referred to as regolith, layers of loosely connected fragmentary debris, produced by meteorite impacts. Measurements of light scattered from such surfaces provides information about the composition and structure of the surface. A suitable way to characterize the scattering properties is to consider how the intensity and polarization of scattered light depends on the particle size, composition, porosity, roughness, wavelength of incident light and the geometry of observation. In the present work, the effect of porosity on bidirectional reflectance as a function of phase angle is studied for alumina powder with grain size of $0.3{\mu}m$ and olivine powder with grain size of $49{\mu}m$ at 543.5 nm. The optical constants of the alumina sample for each porosity were calculated with Maxwell Garnett effective medium theory. On using each of the optical constants of alumina sample in Mie theory with the Hapke model the variation of bidirectional reflectance is obtained as a function of phase angle with porosity as a parameter. Experimental reflectance data are in good agreement the model. For the olivine sample the effect of porosity is studied using Hapke (2008).

• 한국광학회지
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• 제30권1호
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• pp.1-7
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• 2019

휴대용 대공유도 미사일(Man-Portable Air Defense System)은 플룸의 중적외선 신호를 추적하는 적 항공기의 대응무기체계이다. 안개 조건에서 입자들에 의한 다중 산란현상은 중적외선 파장에서의 투과율과 휴대용 대공유도 미사일 탐지성능에 영향을 준다. 그러므로 본 연구에서 다양한 안개조건과 플룸의 특성에 따른 휴대용 대공유도 미사일의 lock-on range를 분석한다. 안개 조건에서의 광학적 소멸특성과 투과율을 분석하기 위해 미산란(Mie scattering) 이론과 복사전달방정식의 분석적 해를 활용하였다. 뿐만 아니라 중적외선 대체광원으로서 섬광탄 화염 신호를 운용했다. 다양한 시정 및 화염 온도조건에서 분석된 lock-on range는 mist 조건에서 크게 감소하며, 화염 온도가 높아질수록 증가하는 것으로 확인하였다.

• 한국대기환경학회지
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• 제7권3호
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• pp.227-234
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• 1991

This study deals with concentration and light extinction of atmospheric aerosol in Seoul. From the measured aerosol size distribution for particle diameter ranging from 0.01 $\mum \sim 1.0 \mum$, extinction coefficient is calculated using the Mie theory. The results show that the diurnal variation of aerosol concentration, in general, reveals the lowest concentration in early morning and afternoon, while the highest at about 8 O'clock owing to the heavy traffic and accumulation of air pollution in the low atmosphere. However, aerosol concentration and extinction coefficient on April 7 give low values due to the advective wind. On the other hand, high aerosol concentration and extinction coefficenat are recorded on April 10 although solar radiation is weak. From the distribution of extinction coefficient we can find that aerosol particles of 0.1 $\mum \sim 1.0 \mum$ in diameter are highly effective on light extinction.

• 통상정보연구
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• 제8권4호
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• pp.277-300
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• 2006

In the initial stage of a national economic development of China, the family business takes enterprise's organizational form ruling position. The private enterprise of China is mainly family business; the family makes the mainly proprietorship in other words. Even in the private enterprise after developing, 70 percents are managed as a family This paper start to study the Transferring Power Patterns in family business using the Company's Life Circle Theory and some other correlative theories. Based on the Transporting Power Model, the paper gives a comprehensive explanation for the choice of transferring power pattern in the family business of China.

• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1801-1807
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• 2001

In multiphase flne the bubble size and velocity. To achieve this, one of approaches is to utilize laser phase-Doppler anemometry. However, it was found that the second order refraction has great impact on PDA sizing method when the relative refractive index of media is less than one. In this paper, the problem of second order refraction is investigated and a model of phase-size correlation to eliminate the measurement errors is introduced for bubble sizing. As a result, the model relates the assumption of single scattering mechanism in conventional phase-Doppler anemometry. The results of simulations based on this new model by using Generalized Lorenz Mie Theory (GLMT) are compared with those based on the conventional method. An optimization method for accurately sizing air-bubble in water has been suggested.

• 통상정보연구
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• 제7권4호
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• pp.245-268
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• 2005

The purpose of this paper is to acquire competitiveness faced with a global business so that Korea and China make them put ICT into practice through industrial policy of regional innovation clustering. In the Chapter 2, overall review of industrial spaces theory and the environment in Global-business is conducted. In the Chapter 3, current main economic issue and West Great Development of China are viewed. Chapter 4 proposes models and strategies for the target of regional innovation clustering and phasing in development. The results of this study is that both country should do more long-term cooperation and collecting intensive knowledge for the property of region and preparatory research of regional innovation clustering than do reckless investment.

• 천문학회보
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• 제37권2호
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• pp.108.1-108.1
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• 2012

Previously we introduced ray-tracing based 3D optical earth system model for specular and scattering properties of all components of the system (i.e. clear-sky atmosphere, land surfaces and an ocean surface). In this study, we enhanced 3-dimensional atmospheric structure with vertical atmospheric profiles for multiple layer and cloud layers using Lambertian and Mie theory. Then the phase dependent disk averaged spectra are calculated. The main results, simulated phase dependent disk averaged spectra and light curves, are compared with the 7 bands(300~1000nm) light curves data of the Earth obtained from High Resolution Instrument(HRI) in Deep Impact spacecraft during Earth flyby in 2008. We note that the results are comparable with the observation.