• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 2010년도 한국우주과학회보 제19권1호
• /
• pp.32.1-32.1
• /
• 2010

The BVR CCD observations of the solar-type contact binary GW Cephei, known as very active dynamically and photometrically, has been made for 20 nights from Nov. 03, 2008 to Dec. 31, 2008 with 1-m reflector of Jincheon station of Chungbuk National University Observatory. A total of 2035 measurements (B: 647, V: 722, R: 666) were obtained to secure new multi-color light curves. From our observations fifteen times of minimum light were newly determined. In this paper both a new period study and an intensive light synthesis were made. Our results will be compared and discussed with the latest thorough studies of the system by Lee et al. (2010).

• Journal of Advanced Marine Engineering and Technology
• /
• 제19권1호
• /
• pp.36-44
• /
• 1995

Melting characteristics of unrestrained liquid ice in a rectangular vessel with heated top wall were investigated experimentally. The liquid ice, a mixture of ice particles and ethylene-glycol aqueous solution, was adopted as a testing material. During the melting process the liquid ice was drawn by buoyancy to the heated top wall of the rectangular vessel where close-contact melting occured. The melting behavior and melting rate of the liquid ice as well as local/mean heat-transfer coefficient at the heated top wall were observed and measured under a variety of conditions of heat flux and various initial concentration of the aqueous binary solution. It was found that the heat transfer of the heated top wall is remarkably promoted by the close-contact melting, and that the dendritic frozen layer at the lower interface of the liquid ice is formed. Photographic evidence demonstrated that plumes containing solute-rich liquid issued from isolated chimneys within the liquid ice layer where segregation of interstitial channel took place.

• 천문학회보
• /
• 제41권1호
• /
• pp.41.2-41.2
• /
• 2016

The follow-up BVRI photometric observations of NSVS 1461538, which was discovered as an $Algol/{\beta}$ Lyr eclipsing variable by Hoffman, Harrison & McNamara (2009), were performed for three years from 2011 to 2013 by using the 61-cm telescope and CCD cameras of Sobaeksan Optical Astronomy Observatory (SOAO). New light curves have deep depths both of the primary and secondary eclipses, rounded shapes outside eclipses and a strong O'Connell effect, indicating that NSVS 1461538 is a typical W UMa close binary system rather than an $Algol/{\beta}$ Lyr type binary star. A period study with all the timings shows that the orbital period may vary in a sinusoidal way with a period of about 5.6 yr and a small semi-amplitude of about 0.008 d. The cyclical period variation was interpreted as a light-time effect due to a tertiary body with a minimum mass of $0.66M{\odot}$. The first photometric solution with the Wilson-Devinney binary model shows that the system is a W-subtype contact binary with the mass ratio ($q=m_c/m_h$) of 3.46, orbit inclination of 85.6 deg and fill-out factor of 30%. From the existing empirical relationship between parameters, the absolute dimension was estimated. The masses and radii of the component stars are $0.28M{\odot}$ and $0.71R{\odot}$ for the less massive but hotter primary star, respectively, and $0.96M{\odot}$ and $1.21R{\odot}$ for the more massive secondary, respectively. Possible evolution of the system is discussed in the mass-radius and the mass-luminosity planes.

• 한국환경과학회지
• /
• 제23권12호
• /
• pp.1987-1998
• /
• 2014

Zeolite was synthesized from power station waste, coal fly ash, as an alternative low-cost adsorbent and investigated for the removal of Sr(II) and Cs(I) ions from single- and binary metal aqueous solutions. In order to investigate the adsorption characteristics, the effects of various operating parameters such as initial concentration of metal ions, contact time, and pH of the solutions were studied in a batch adsorption technique. The Langmuir model better fitted the adsorption isotherm data than the Freundlich model. The pseudo second-order model was found more applicable to describe the kinetics of system. The adsorption capacities of Sr(II) and Cs(I) ions obtained from the Langmuir model were 1.7848 mmol/g and 0.7640 mmol/g, respectively. Although the adsorption capacities of individual Sr(II) and Cs(I) ions was less in the binary-system, the sum of the total adsorption capacity (2.3572 mmol/g) of both ions in the binary-system was higher than the adsorption capacity of individual ion in the single-system. Comparing the homogeneous film diffusion model with the homogeneous particle diffusion model, the adsorption was mainly controlled by the particle diffusion process.

• 방사성폐기물학회지
• /
• 제19권3호
• /
• pp.353-366
• /
• 2021

The solubilities of different multicomponent lanthanide oxide (Ln₂O₃) solid solutions including binary (Ln₁ and Ln₂ = La, Nd, Eu, or Tm), ternary (Ln₁, Ln₂, and Ln₃ = La, Nd, Eu, or Tm), and higher systems (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) were studied after aging for four weeks at 60℃. Our recent study revealed that the phase transformations in binary ((La, Nd) and (La, Eu)) and ternary (La, Nd, Eu) systems are responsible for the formation of (La, Nd)(OH)₃, (La, Eu)(OH)₃, and (La, Nd, Eu)(OH)₃ solid solutions, respectively. The variations in the mole fractions of La³⁺, Nd³⁺, and Eu³⁺ in the sample solutions of these hydroxide solid solutions indicated that a thermodynamic equilibrium might account for the apparent La, Nd, and Eu solubilities. Conversely, the binary and ternary systems containing Tm₂O₃ as the heavy lanthanide oxide retained the oxide-based solid solutions, and their solubility behaviors were dominated by their congruent dissolutions. In the higher multicomponent system, the X-ray diffraction patterns of the solid phases, before and after contact with the aqueous phase indicated the formation of a stable oxide solid solution and their solubility behavior was explained by its congruent dissolution.

• Journal of Astronomy and Space Sciences
• /
• 제12권2호
• /
• pp.196-203
• /
• 1995

소백산천문대의 61cm 망원경을 사용하여 식쌍성 SW Lyn에 대한 UBV관측을 1983년 9월 부터 1987년 3월까지 7일밤 동안 수행하여 광도곡선을 얻었다. 이 광도곡선은 부극심을 중심으로 좌우가 비대칭이며 그 정도는 파장이 짧을수록 심한 것으로 나타났다. 비대칭 광도변화를 만드는 윈인을 흑점이라고 가정하고, 우리의 광도곡선 중에서 B와 V광도곡선을 WD 방법으로 분석하여 해를 얻었다. 그 결과 SW Lyn이 접촉에 가까운 준접촉계임이 밝혀졌으며 Case A 진화를 하는것으로 보인다.

• Journal of Astronomy and Space Sciences
• /
• 제15권1호
• /
• pp.83-90
• /
• 1998

Svechnikow & Kuznetsova (1990)의 Catalogue of Approximate Photometric and Absolute Elements of Eclipsing Variable로 부토 3780개의 식 쌍성들을 이용하여 식 쌍성의 질량-궤도 각 운동량과의 상관 관계를 조사하였다. 그 결과 쌍성이 진화하는 동안 궤도 각 운동량이 보전되지 못하며, 비록 일정한 값을 갖지는 않지만 점진적으로 분리형에서 준분리 형으로 그리고 접촉형으로 진화할수록 그 값이 감소하는 것으로 나타났다.

• Journal of Astronomy and Space Sciences
• /
• 제14권1호
• /
• pp.33-43
• /
• 1997

소백산 천문대의 61cm 망원경을 사용하여 1995년 10월부터 12월 사이의 10일 동안 CCD 측광관측에 의하여 EB형 식쌍성 V388 Cyg의 3색 (B, V&R)의 광도곡선을 얻었다. 새로운ㄴ 3색의 광도곡선을 Wilson-Devinney model에 동시에 적용하여 이 별의 궤도요소를 얻었다. 그 결과 현재로서는 V388 Cyg이 접촉형인지 준분리형인지를 판단하지 못하였다. 한편, 지금까지 발표된 이 별의 극심시각을 수집하여 주기변화를 조사하였으며, 그 결과 일정한 주기 감소를 나타내는 $-4.83{\times}10^{-10}$의 2차 함수를 포함하는 새로운 광도요소를 계산하였다.

• 천문학논총
• /
• 제30권2호
• /
• pp.539-541
• /
• 2015

We present a new tool for studying the spectral energy distributions (SEDs) and color-magnitude diagrams (CMDs) of galaxies and star clusters, BINARY STAR TO FIT (BS2fit). A key feature of this tool is that it takes the effects of binaries, stellar rotation and star formation history into account. It can be used to determine many parameters, including distance, extinction, binary fraction, rotational star fraction, and star formation history. Because more factors are included than in previous tools, BS2fit can potentially give new insight into the properties of galaxies and clusters. One can contact the authors for cooperation and helps via.

• 한국정밀공학회지
• /
• 제11권5호
• /
• pp.124-133
• /
• 1994

Many of non-contact measuring systems are used to estimate surface characteristics owing to their advantages of high speed and undanaged test. In this paper, a new measuring system is proposed to acquire image from CCD camera through back light illumination. Lowpass filter is very useful in view of noise removal and optimum binary image can be made through histogram equalization which is one of the histogram technique to maximize brightness intensity between workpiece and background. Laplacian operator is used to detect workpiece edge from binary image. In case of image treatment applying Laplacian operator, surface roughness is calculated by introducing conversion coefficient for coordinate of pixel which edge is composed of. In summary, the work is concerned with the development of a new technique for roughness measurement by the image processing in turning.