• Title/Summary/Keyword: light curve solution

Search Result 45, Processing Time 0.033 seconds

CCD Photometric Observations and Light Curve Synthesis of the Near-Contact Binary XZ Canis Minoris (근접촉쌍성 XZ CMi의 CCD 측광관측과 광도곡선 분석)

  • Kim, Chun-Hwey;Park, Jang-Ho;Lee, Jae-Woo;Jeong, Jang-Hae;Oh, Jun-Young
    • Journal of Astronomy and Space Sciences
    • /
    • v.26 no.2
    • /
    • pp.141-156
    • /
    • 2009
  • Through the photometric observations of the near-contact binary, XZ CMi, new BV light curves were secured and seven times of minimum light were determined. An intensive period study with all published timings, including ours, confirms that the period of XZ CMi has varied in a cyclic period variation superposed on a secular period decrease over last 70 years. Assuming the cyclic change of period to occur by a light-time effect due to a third-body, the light-time orbit with a semi-amplitude of 0.0056d, a period of 29y and an eccentricity of 0.71 was calculated. The observed secular period decrease of $-5.26{\times}10^{-11}d/P$ was interpreted as a result of simultaneous occurrence of both a period decrease of $-8.20{\times}10^{-11}d/P$ by angular momentum loss (AML) due to a magnetic braking stellar wind and a period increase of $2.94{\times}10^{-11}d/P$ by a mass transfer from the less massive secondary to the primary components in the system. In this line the decreasing rate of period due to AML is about 3 times larger than the increasing one by a mass transfer in their absolute values. The latter implies a mass transfer of $\dot{M}_s=3.21{\times}10^{-8}M_{\odot}y^{-1}$ from the less massive secondary to the primary. The BV light curves with the latest Wilson-Devinney binary code were analyzed for two separate models of 8200K and 7000K as the photospheric temperature of the primary component. Both models confirm that XZ CMi is truly a near-contact binary with a less massive secondary completely filling Roche lobe and a primary inside the inner Roche lobe and there is a third-light corresponding to about 15-17% of the total system light. However, the third-light source can not be the same as the third-body suggested from the period study. At the present, however, we can not determine which one between two models is better fitted to the observations because of a negligible difference of $\sum(O-C)^2$ between them. The diversity of mass ratios, with which previous investigators were in disagreement, still remains to be one of unsolved problems in XZ CMi system. Spectroscopic observations for a radial velocity curve and high-resolution spectra as well as a high-precision photometry are needed to resolve some of remaining problems.

DETERMINATIONS OF ITS ABSOLUTE DIMENSIONS AND DISTANCE BY THE ANALYSES OF LIGHT AND RADIAL-VELOCITY CURVES OF THE CONTACT BINARY - I. V417 Aquilae (접촉쌍성의 광도와 시선속도곡선의 분석에 의한 절대 물리량과 거리의 결정 -1. V417 Aquilae)

  • 이재우;김천휘;이충욱;오규동
    • Journal of Astronomy and Space Sciences
    • /
    • v.21 no.2
    • /
    • pp.73-82
    • /
    • 2004
  • New photometric and spectroscopic solutions of W-type overcontact binary V 417 Aql were obtained by solving the UBV light curves of Samec et al. (1997) and radial-velocity ones of Lu & Rucinski (1999) with the 2003 version of the Wilson-Devinney binary code. In the light curve synthesis the light of a third-body, which Qian (2003) proposed, was considered and obtained about 2.7%, 2.2%, and 0.4% for U, B, and V bandpasses, respectively. The model with third-light is better fitted to eclipse parts than that with no third-light. Absolute dimensions of V417 Aql are determined from our solution as $M_1$= 0.53 $M_{*}$, $M_2$= 1.45 $M_{*}$, $R_1$= 0.84 $R_{*}$, and $R_2$= 1.31 $M_{*}$, and the distance to it is deduced as about 216pc. Our distance is well consistent with that (204pc) derived from Rucinski & Duerbeck's (1997) relation, $M_{v}$ = $M_{v}$(log P, B-V), but is more distant than that (131$\pm$40pc) determined by the Hipparcos trigonometric parallax. The difference may result from the relatively large error of Hipparcos parallax for V 417 Aql.l.

THE ELECTROCHEMICAL STUDY ON CORROSION RESISTANCE OF VARIOUS DENIAL MAGNETIC ATTACHMENTS (수종 치과용 자석유지장치의 부식저항성에 대한 전기화학적 연구)

  • Sohn Byoung-Sup;Chang Ik-Tae;Heo Seong-Joo;Keak Jai-Young
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.39 no.4
    • /
    • pp.336-350
    • /
    • 2001
  • The purpose of this study was to investigate corrosion tendency and to compare corrosion resistance of three dental magnetic attachments and its keeper alloy by coercive, electrochemical method. By using petentiodynamic polarization technique, magnetic elements and its keeper alloy of Magfit EX600 system(MF, MFK), Dyna ES regular system(DN, DNK) and Shiner SR magnet system(SR, SRK) were corroded electrochemically in 0.9% NaCl electrolytic solution. Open-circuit potential and anodic polarization curve was measured with Potentiostat(model 273 EG&E) and polarization curve was created by current density per square area following scanning of increased series of voltage in the rate of 1.0mV per second. Before and after electrochemical corrosion, the surface roughness test was done. Thereafter the change of mean surface roughness value(Ra) and mean peak value(Rt) of surface roughness was compared one another. In order to observe the corroded surface of each specimen, metallurgical light microscopic(${\times}37.5$) and scanning electron microscopic view(SEM ${\times}100$) was taken and compared one another. Conclusion is followings. 1. All of six covering metal of dental magnetic attachments and its keeper alloy were corroded in various degree after electrochemical corrosion. 2. The corrosion resistance of which used in this experiment is the following in high order; DNK, MFK, DN, MF, SRK and SR. 3. Especially Shiner magnet system and its keeper alloy were more severely corroded after electrochemical corrosion and the change of Ra Rt value were more increased than others. 4 Metallurgical and scanning electron microscopic view showed the pitting corrosion tendency of all experimental alloy but DNK and SR. 5. Covering metal of magnet was more corroded than its keeper alloy.

  • PDF

A Study on the Effect of Compressive Residual Stress for Corrosion Property of SUP-9 Steel Using as Suspension Material (현가장치재 SUP-9강의 부식특성에 미치는 압축잔류응력의 영향에 관한 연구)

  • Ru Hyung-Ju;An Jae-pil;Park Keyung-dong
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.29 no.7 s.238
    • /
    • pp.930-937
    • /
    • 2005
  • One of the useful technology for light-weightening of components required in the automobile and machine industry is to use of high strength materials. To improve material properties, carbonizing treatment, nitrifying treatment, and shot-peening method are representatively applied, However, the shot-peening method is generally used to remove the surface defect of steel and to improve the fatigue strength on surface. Benefits by shot peening are to make increase resistance against fatigue, stress corrosion cracking, fretting, galling, erosion and closing of pores. In this paper, investigated the effect of shot peening on the corrosion of SUP-9 steel immersed in $3.5\%$ NaCl solution and corrosion characteristics by the heat treatment during shot peening process. The immersion test was performed on the four kinds of specimens. Corrosion potential, polarization curve, residual stress and etc. were investigated from the experimental results.

Development of Bioluminescence Immunoassay Using Photoprotein, Aequorin and Site-directed Immobilization

  • Shim, Yu-Nee;Rhee, In-sook
    • Bulletin of the Korean Chemical Society
    • /
    • v.24 no.1
    • /
    • pp.70-74
    • /
    • 2003
  • The heterogeneous bioluminescence immunoassay for digoxin was developed using photoprotein, native aequorin as a label and the site-directed immobilization technique based on avidin/biotin interaction. Aequorin is a bioluminescence protein, originally isolated from the jellyfish Aequoria Victoria and an attractive label in analytical applications because of sensitive detection due to virtually no background bioluminescent signal. Digoxin is a cardioactive drug, and its therapeutic level in serum is at low concentration with very narrow therapeutic index. The aequorin-digoxigenin conjugates were synthesized by the N-hydroxysuccinimide ester method and characterized in terms of bioluminescent residual activity. The resulting dose-response curve shows that the detection limit is $1.0\;{\times}\;10^{-10}\;M$ and a dynamic range is three orders of magnitude, which was obtained by $1.0\;{times}\;10^{-10}\;M$ conjugate and 0.9 μg/mL anti-digoxin antibody. Three structurally similar molecules to digoxin were examined for their cross-reactivity. None of these three compounds showed any crossreactivity with digoxin antibody employed in this study. Standard amounts of digoxin corresponding to the therapeutic range were spiked into the each serum solution. Study of the serum matrix effect indicated that correlation coefficient shows good agreement between luminescence light intensity between in buffer and in serum.

Utilizing Block chain in the Internet of Things for an Effective Security Sharing Scheme

  • Sathish C;Yesubai Rubavathi, C
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.17 no.6
    • /
    • pp.1600-1619
    • /
    • 2023
  • Organizations and other institutions have recently started using cloud service providers to store and share information in light of the Internet of Things (IoT). The major issues with this storage are preventing unauthorized access and data theft from outside parties. The Block chain based Security Sharing scheme with Data Access Control (BSSDAC) was implemented to improve access control and secure data transaction operations. The goal of this research is to strengthen Data Access Control (DAC) and security in IoT applications. To improve the security of personal data, cypher text-Policy Attribute-Based Encryption (CP-ABE) can be developed. The Aquila Optimization Algorithm (AOA) generates keys in the CP-ABE. DAC based on a block chain can be created to maintain the owner's security. The block chain based CP-ABE was developed to maintain secures data storage to sharing. With block chain technology, the data owner is enhancing data security and access management. Finally, a block chain-based solution can be used to secure data and restrict who has access to it. Performance of the suggested method is evaluated after it has been implemented in MATLAB. To compare the proposed method with current practices, Rivest-Shamir-Adleman (RSA) and Elliptic Curve Cryptography (ECC) are both used.

TIME-SERIES PHOTOMETRY OF VARIABLE STARS IN THE GLOBULAR CLUSTER NGC 288

  • Lee, Dong-Joo;Koo, Jae-Rim;Hong, Kyeongsoo;Kim, Seung-Lee;Lee, Jae Woo;Lee, Chung-Uk;Jeon, Young-Beom;Kim, Yun-Hak;Lim, Beomdu;Ryu, Yoon-Hyun;Cha, Sang-Mok;Lee, Yongseok;Kim, Dong-Jin;Park, Byeong-Gon;Kim, Chun-Hwey
    • Journal of The Korean Astronomical Society
    • /
    • v.49 no.6
    • /
    • pp.295-306
    • /
    • 2016
  • We present the results of BV time-series photometry of the globular cluster NGC 288. Observations were carried out to search for variable stars using the Korea Microlensing Telescope Network (KMTNet) 1.6-m telescopes and a 4k pre-science CCD camera during a test observation from August to December, 2014. We found a new SX Phe star and confirmed twelve previously known variable stars in NGC 288. For the semi-regular variable star V1, we newly determined a period of 37.3 days from light curves spanning 137 days. The light-curve solution of the eclipsing binary V10 indicates that the system is probably a detached system. The pulsation properties of nine SX Phe stars were examined by applying multiple frequency analysis to their light curves. We derived a new Period-Luminosity (P-L) relation, ${\langle}M_V{\rangle}=-2.476({\pm}0.300){\log}P-0.354({\pm}0.385)$, from six SX Phe stars showing the fundamental mode. Additionally, the period ratios of three SX Phe stars that probably have a double-radial mode were investigated; $P_{FO}/P_F=0.779$ for V5, $P_{TO}/P_{FO}=0.685$ for V9, $P_{SO}/P_{FO}=0.811$ for V11. This paper is the first contribution in a series assessing the detections and properties of variable stars in six southern globular clusters with the KMTNet system.

Studies on the quantitative determination of Capsaicin in various species of the genus Capsicum (고추중의 Capsaicin 정량(定量)에 관(關)한 연구(硏究))

  • Lee, Tae-Yeong;Park, Seong-O
    • Applied Biological Chemistry
    • /
    • v.4
    • /
    • pp.23-28
    • /
    • 1963
  • Various species of the genus Capsicum contain in their fruits an intensively sharp and pungent substance, Capsaicin, which was first isolated in an almost pure state by Thresh. Containing the pungent principle, Capsicums are used extensively in food as a spice and in medicine as a rubefacient and carminative. Numerous methods have been proposed for the isolation, the chemical structure and the quantitative determination of Capsaicin. Modifying the several methods described before, the Capsaicin contents in various species of the genus Capsicum were determined as follows. (1) The isolation of pure Capsaicin was the essential first step for the determination of Capsaicin contents. Powdered cayenne pepper was extracted with acetone. By the method of ether alkali partition extraction slightly modified at this laboratory and by the recrystallization with light petroleum ether that was repeated ten times, the pure crystalline Capsaicin was obtained. Using this Capsaicin, the standard absorption curve was drawn with Beckman spectrophotometer model DU for the quantitative determination of Capsaicin. 92) The powdered sample was extracted in a Soxhlet extractor with ether-acetone solvent system(3:1) for 25 hours. Capsaicin in this ether-acetone extracts was efficiently separated in a pure state by paper partition chromatography using 58% methanol solution as developing agent. It was found that 58% methanol was one of the most valuable solvent to separate Capsaicin from impurities such as sterols, fatty acids, waxes and carotenoid pigments. (3) The colorimetric method modifying the Schulte-Kruger's method which consists of measuring the red color produced with diazobenzenesulphonic acid was used. Capsaicin in various species of the genus Capsicum was determined quantitatively with use of Beckman spectrophotometer model DU at $480\;m{\mu}$.

  • PDF

Dyeability and functionality of Catechu(Part I) -Characteristics of Catechu and Dyeing properties of Cotton- (아선약의 염색성과 기능성(제1보) -아선약 색소의 특성과 면섬유에 대한 염색성-)

  • Nam, Ki-Yeon;Lee, Jung-Soon
    • Korean Journal of Human Ecology
    • /
    • v.19 no.4
    • /
    • pp.699-707
    • /
    • 2010
  • Catechu is widely used as in natural dyeing as well as in various medicines and tannage. This study investigated the dyeing properties and functionality of Catechu through a series of dyeing experiments using cotton fabric. It was shown that the absorbance of Catechu solution has two peaks at 220nm and 280nm. Thus, it can be concluded that the color constituent of Catechu is a catechol tannin and color tone is YR. The dyeability of Catechu increases as the concentration of the dye is increased. Its variation was shown to be similar to the isothermal absorption curve of the Freundlich. As dyeing time was increases, the dyeability did not change significantly after the 30 minute mark was passed. At high temperatures the dyeability was shown to increase. As the dyeing temperature was increased the color of dyeing fabrics changes from Y and YR to R. Experiments with pre-mordanting method showed that various colors can be obtained using Catechu. Cotton is effective in using K, Cu, Fe mordants, and the dyeability was shown to be improved with low pH. Both washing fastness and light fastness were shown to be low. However, the fabric color gradually changed to red was due to mailard reaction of catechol tannin causing by repeated washing and sunlight. The ultraviolet-cut ability was improved for cotton fabric dyed with Catechu. Also, dyed fabric with Catechu showed very good antimicrobial abilities at 99.9%.

Simultaneous velocity and temperature measurement of thermo-fluid flows by using particle imaging technique (화상처리기법을 이용한 온도장 및 속도장 동시 측정기법 개발)

  • Lee, Sang-Joon;Baek, Seung-Jo;Yoon, Jong-Hwan;Doh, Deog-Hee
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.20 no.10
    • /
    • pp.3334-3343
    • /
    • 1996
  • A quantitative flow visualization technique was developed to measure velocity and temperature fields simultaneously in a two-dimensional cross section of thermo-fluid flows. Thermochromic liquid crystal(TLC) particles are used as temperature sensor and velocity tracers. Illuminating a thermo-fluid flow with a thin sheet of white light, the reflected colors from the TLC particles in the flow were captured simultaneously by two CCD cameras; a 3-chip CCD color camera for temperature field measurement and a black and white CCD camera for velocity field measurement. Variations of temperature field were measured by using a HSI true color image processing system and TLC solution. The relationship between the hue values of TLC color image and real temperature was obtained and this calibration curve was used to measure the true temperature under the same camera and illumination condition. The velocity field was obtained by using a 2-frame PTV technique using the concept of match-probability to track true velocity vectors from two consecutive image frames. These two techniques were applied at the same time to the unsteady thermal-fluid flow in a Hele-Shaw cell to measure the temperature and velocity field simultaneously and some results are discussed.