• Title/Summary/Keyword: White

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Monitoring Observations of Active White Dwarf Binary Systems

  • Lee, Hee-Won;Choi, Bo-Eun;Im, Myungshin;Lim, Gu
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.60.3-60.3
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    • 2019
  • Binary systems of a white dwarf showing mass transfer activities are classified into cataclysmic variables and symbiotic stars. In the case of cataclysmic variables, the companion is usually a late type main sequence star filling its Roche lobe, where material is transferred through the inner Lagrangian point to form an accretion disk around the white dwarf. The disk becomes unstable and highly viscous when the surface density exceeds the critical density, leading to dwarf nova outbursts. In contrast, symbiotic stars are wide binary systems having a giant as the mass donor. Some fraction of giant stellar wind is accreted to the white dwarf giving rise to various symbiotic activities. In particular, half of symbiotics show Raman O VI at 6830 and 7088, which are important spectroscopic probe of mass transfer process. Monitoring observations using 1 m class telescopes will produce valuable information regarding the mass loss and mass transfer to white dwarf stars, shedding much light on the last stage of stellar evolution of low and intermediate mass stars.

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Efficiency of LED Trap on Controlling Tobacco Whitefly, Bemisia tabaci Adults in Greenhouse (온실에 발생하는 담배가루이 성충에 대한 LED 트랩 방제효과)

  • Jeon, Ju-Hyun;Lee, Sang-Guei;Lee, Hoi-Seon
    • Journal of Applied Biological Chemistry
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    • v.57 no.3
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    • pp.243-245
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    • 2014
  • To evaluate light-emitting diode (LED) as potential attractants for Bemisia tabaci adults, attractiveness of white and yellow LED traps were investigated in greenhouse. The yellow LED trap showed the most attractive to B. tabaci adults, followed by a similarly attraction to the white LED trap, whereas the control (no light trap) was little attractive to B. tabaci adults. These results suggested that yellow and white LED traps could be used for environment-friendly insect pest control.

Accuracy Improvement and Systematic Bias Analysis of Scanning White Light Interferometry for Free-form Surfaces Measurements (자유 곡면 형상 측정을 위한 백색광 주사 간섭계의 정확도 향상 및 시스템 오차 분석)

  • Ghim, Young-Sik;Davies, Angela;Rhee, Hyug-Gyo
    • Journal of the Korean Society for Precision Engineering
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    • v.31 no.7
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    • pp.605-613
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    • 2014
  • Scanning white-light interferometry is an important measurement option for many surfaces. However, serious profile measurement errors can be present when measuring free-form surfaces being highly curved or tilted. When the object surface slope is not zero, the object and reference rays are no longer common path and optical aberrations impact the measurement. Aberrations mainly occur at the beam splitter in the interference objective and from misalignment in the optical system. Both effects distort the white-light interference signal when the surface slope is not zero. In this paper, we describe a modified version of white-light interferometry for eliminating these measurement errors and improving the accuracy of white-light interferometry. Moreover, we report systematic errors that are caused by optical aberrations when the object is not flat, and compare our proposed method with the conventional processing algorithm using the random ball test.

Spatial Analysis of White-naped Crane(Grus vipio) Habitats in the Han-River Estuary with GIS application (GIS를 이용한 재두루미의 한강 하구 서식지 이용에 대한 공간 분석)

  • Kim, Sung Ok;Lee, Sang Don
    • Journal of Wetlands Research
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    • v.10 no.2
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    • pp.173-178
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    • 2008
  • The habitat composition in the Han-river estuary, where white-naped crane(Grus vipio; endangered migrating bird) spend winter, was analysed by the geographic information system(GIS). And the habitat use pattern of white-naped crane collected by satellite tracking method was analysed. The % composition of seven habitat categories of land cover classification was compared for the buffers of radii 100 m, 200 m, 500 m, and 1 km, respectively, around the white-naped crane position point(n=228), and the statistical analysis was done using chi-square test. The results showed no selective use of habitat area by white-naped crane in the buffers of 100 m, 200 m and 500 m, but showed clear selection of habitat use (p < 0.05) in the case of 1 km buffer.

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Fabrication of White OLED Using Zn(HPB)2 and Zn(HPQ)2 as a emitting layer (Zn(HPB)2와 Zn(HPQ)2를 이용한 White OLED의 제작 및 전기적 특성)

  • Kim, Dong-Eun;Kim, Byoung-Sang;Kim, Gyong-Chol;Shin, Hoon-Kyu;Kwon, Young-Soo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.12
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    • pp.2240-2244
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    • 2010
  • We have studied white OLED using two types of Zn-complexes as a emitting layer. We synthesized new emissive materials $Zn(HPQ)_2$ as a yellow emitting material and $Zn(HPB)_2$ as a blue emitting material. Zn-complexes have a low molecular compound and thermal stability. The fundamental structures of the fabricated OLED was ITO / NPB (40nm) / $Zn(HPB)_2$ (30nm) / $Zn(HPQ)_2$ / LiF / Al. We varied the thickness of the $Zn(HPQ)_2$ layer 20, 30 40 nm. When the thickness of the $Zn(HPQ)_2$ layer was 20 nm, white emission was achieved. The maximum luminance was 12,000 cd/$m^2$ at a current density of 800 mA/$cm^2$. The CIE coordinates of the white emission was (0.319. 0.338) at an applied voltage of 10 V.

Improvement of Efficiency Varying Ratio in Hybrid White OLED (도핑 비율에 따른 하이브리드 백색 OLED의 효율 향상에 관한 연구)

  • Kim, Nam-Kyu;Shin, Hoon-Kyu;Kwon, Young-Soo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.9
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    • pp.571-575
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    • 2014
  • We synthesized new materials of $Zn(HPB)_2$ and Ir-complexes as blue or red emitting material. We fabricated white Organic Light Emitting Diodes (OLED) by using $Zn(HPB)_2$ for the blue emitting layer, Ir-complexes for the red emitting layer and $Alq_3$ for the green emitting layer. We fabricated white OLED by using double emitting layers of $Zn(HPB)_2$:Ir-complexes and $Alq_3$. The doping rate of Ir-complexes was varied, such as 0.2%, 0.4%, 0.6%, and 0.8%, respectively. When the doping rate of $Zn(HPB)_2$:Ir-complexes was 0.6%, white emission was achieved. The Commission Internationale de l'Eclairage (CIE) coordinates of the white emission was (0.322, 0.312).

Development of a 15-day Interval Spraying Program for Controlling Major Apple Diseases

  • Lee, Dong-Hyuck;Kim, Dae-Hee;Shin, Ho-Cheol;Uhm, Jae-Youl
    • The Plant Pathology Journal
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    • v.24 no.4
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    • pp.439-446
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    • 2008
  • A fungicidal spray program for effective control of three major apple diseases in Korea (white rot, bitter rot, and Marssonina blotch) was developed. This was based on our previous studies showing that application of ergosterol biosynthesis inhibitors (EBIs) in early or mid-August can eradicate white rot infection in fruit and that some protective fungicides show after-infection activity against white rot. The basic spray program focused on control of white rot, the main target disease, and the fungicides were sprayed at 15-day intervals from petal fall to late August using fungicides that show after-infection and EBI activity. The basic spray program was modified over 4 successive years to improve control efficacy against bitter rot and Marssonina blotch, which sometimes cause as much damage as white rot. Modifications to the regime were made every year by replacing one fungicide in the basic program at a specific spraying time. Substitution of only one fungicide in the spray program, even early in the growing season, greatly influenced the final disease incidence at harvest. Applying this principle, a moderately efficient spray program for cv. Fuji that increased the spray interval from 10 to 15 days and thus reduced the number of sprays required per crop season was developed.

Studies On The Quality Of Soybean Sprouts Grown Under Light (광조사에 의한 콩나물의 질적변화)

  • 오승희
    • Journal of the Korean Professional Engineers Association
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    • v.18 no.2
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    • pp.16-22
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    • 1985
  • This study was carried out to evaluate the quality of soybean sprouts grown under three different sources of light. The soybean was germinated under light through blue (251 ux), red (751 ux) and white (50 to 200 lux) polyethylene films at 25$^{\circ}C$ for 10hr./day. Vitamin C, chlorophyll, cellulose and total protein contents were determined and texture was evaluated by tasting soybean sprouts soup. protein pattern in the soybean sprouts were investigated using polyacrylamide gel electrophoresis. Vitamin C, chlorophyll and cellulose contents were increased by white light intensity. The texture of the sprouts grown under white light (50 lux, 100 lux) was better than darkness, but fought under 200 lux. Vitamin C contents of soybean sprouts grown under various sources of light (in order of light : blue > white > red) were higher than theses of ones grown in the darkness. Biosynthesis of chlorophyll was not correlated to Vitamin C content. Total protein contents of cotyledon was not changed significantly under light irradiation. But the soybean sprouts grown under different quality of light, hypocotyl was higher than those grown darkness. (37% and 20% higher for blue light and white light) Densitometric tracing of disc polyacrylamide gel electrophoretic patterns showed that protein of hypocotyl under white light had more high molecular weight protein.

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Transient asymptomatic white matter lesions following Epstein-Barr virus encephalitis

  • Jang, Yoon-Young;Lee, Kye-Hyang
    • Clinical and Experimental Pediatrics
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    • v.54 no.9
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    • pp.389-393
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    • 2011
  • We present the case of a patient with Epstein-Barr virus (EBV) encephalitis who developed abnormal white matter lesions during the chronic phases of the infection. A 2-year-old-boy was admitted for a 2 day history of decreased activity with ataxic gait. The results of the physical examination were unremarkable except for generalized lethargy and enlarged tonsils with exudates. Brain magnetic resonance imaging (MRI) at admission showed multiple high signal intensities in both basal ganglia and thalami. The result of EBV polymerase chain reaction (PCR) of the cerebral spinal fluid was positive, and a serological test showed acute EBV infection. The patient was diagnosed with EBV encephalitis and recovered fully without any residual neurologic complications. Subsequently, follow-up MRI at 5 weeks revealed extensive periventricular white matter lesions. Since the patient remained clinically stable and asymptomatic during the follow-up period, no additional studies were performed and no additional treatments were provided. At the 1-year follow-up, cranial MRI showed complete disappearance of the abnormal high signal intensities previously seen in the white matter. The patient continued to remain healthy with no focal neurologic deficits on examination. This is the first case of asymptomatic self-limited white matter lesions seen in serial MRI studies in a Korean boy with EBV encephalitis.

Approach for Cloning and Characterization of Blue/White Flower Color Specific cDNA Clones from Two Commelina Species

  • Lee Gunho;Yeon Mooshik;Hur Yoonkang
    • Journal of Plant Biotechnology
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    • v.7 no.1
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    • pp.45-50
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    • 2005
  • To clone blue and white flower color specific genes, mRNA differential display was carried out with two different Commelina species, C. communis Linne for blue color and C. coreana Leveille for. leucantha Nakai for white color. Fifty two and 100 cDNA clones specific for blue or white flower color, respectively, were ranging from 200 to 700 bp in size. From the reverse northern blot analysis, 12 and 7 positive clones were selected for blue and white flower, respectively. These clones appear to be novel cDNAs for these Commelina plants, but not color specific. This finding was supported by the northern blot analysis. However, two clones, B18 and B19, derived from blue flowered Commelina were highly expressed than in the white Commelina species, implying that further study will be valuable. The results indicated that both mRNA display experiment and dot blot analysis may not sensitive enough to clone color-determining gene from the plant, leading to explore more advanced method, like high-density colony array study (HDCA).