• Title/Summary/Keyword: Dim light

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Photoadaptation of Green Sulfur Photosynthetic Bacteria Chlorobium phaeobacteroides

  • Hirabayashi, Hiroki;Ohmura, Satoshi;Ishii, Takasada;Takaichi, Shinichi;Uehara, Kaku
    • Journal of Photoscience
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    • v.9 no.2
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    • pp.364-366
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    • 2002
  • Photoadaptation of Chlorobium (Cb.) phaeobacteroides was investigated under dim and strong light intensity. Absorption spectra of these whole cellIs were different each other. The Soret band intensity and the Qy bandwidth of BChl e in c디l grown under dim light intensity were smaller and more broadened than those under strong light intensity. From HPLC analysis of the pigments, total carotenoid (Car) / bacterochorolphyll (BChl) e ratio of cell increased wi1h increase of light intensities. But camposition of BChl e hamologs almost unchanged. Cb. phaeobacteroides contains 11 kinds of Car including isorenieratene and beta-isorenieratene as major Car. The campositions of Car were different for cells grown under dim and strong light intensities. In conclusion, Cb. phaeobacteroides changes total amount and canposition of Car to adapt various light intensities, while homolog canposition of BChle unchange.

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Photographic Color Reproduction Based on Color Variation Characteristics of Digital Camera

  • Kim, Ui-Seong;Lee, Jong-Min;Kim, Yong-Min;Park, Ki-Tae;Moon, Young-Shik
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.5 no.11
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    • pp.2160-2174
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    • 2011
  • In this paper, a new technique for color reproduction based on color variation characteristics of digital camera under a dim light condition is proposed. Generally, photographers should adjust a camera exposure properly for obtaining an image with real color tone of subjects. Thus, in case of taking a picture under a dim light condition, the exposure time of a camera has to be relatively longer than the one under a bright light condition. Although images with real color tone of the subject are obtained, the images may get blurred due to the shaky hands of photographer holding the camera. In order to avoid the blur effect, an input image is captured from a camera set as a short exposure time under a dim light condition. Then we propose a method to reproduce color tone of the dim input image. To this end, color variation characteristics which represent color variations of a digital camera are first extracted by analyzing the Macbeth color checker images taken under various exposure values. Then, a color reproduction is performed by an estimation based on the color variation characteristics. Experimental results have shown that the proposed method has achieved better performance of color reproduction, compared with existing methods.

Review of Low-Dimensional Nanomaterials for Blue-Light Emission

  • Won Kook Choi
    • Journal of Sensor Science and Technology
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    • v.32 no.6
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    • pp.391-402
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    • 2023
  • Low-dimensional (zero-dimensional (0-dim), 2-dimensional (2-dim)) nanoparticles, such as chalcogenide compound semiconductors, III-V semiconductors, transition metal dichalcogenides (TMDs), II-VI semiconductors, nanocarbons, hybrid quantum dots (QDs), and perovskite QDs (PQDs), for which blue light emission has been observed, are reviewed. Current synthesis and device fabrication technologies as well as their prospective applications on next-generation quantum-dot-based light-emitting diodes are discussed.

Impact of Dim Artificial Light at Night (dALAN) Exposure during Sleep on Human Fatigue (야간 수면 중 약한 인공 빛 노출이 피로도에 미치는 영향)

  • Cho, Ah-reum;Cho, Chul-Hyun;Yoon, Ho-Kyoung;Moon, Joung Ho;Lee, Heon-Jeong;Kim, Leen
    • Sleep Medicine and Psychophysiology
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    • v.23 no.2
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    • pp.53-60
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    • 2016
  • Objectives: Exposure to light at night has become pervasive in modern society. The impact of dim artificial light at night (dALAN) exposure on sleep and fatigue is not well recognized. We aim to study the impact of dALAN exposure during sleep on human fatigue. Methods: 30 healthy young male volunteers from 21 to 29 years old were enrolled in the study. They were randomly divided into two groups depending on light intensity (Group A : 5 lux and Group B : 10 lux). Data were gathered from each participant after each night with no light (Night 1) followed by the next night (Night 2) with two different dim light conditions (5 or 10 lux) by means of self-reported fatigue scale. Results: Exposure to dALAN during sleep was significantly associated with increased overall fatigue (F = 19.556, p < 0.001) and ocular discomfort (F = 5.671, p = 0.028). Conclusion: We found that dALAN during sleep likely affects human fatigue in some aspects. These findings indicate that dALAN during sleep exerts a negative effect on human fatigue.

Effects of the Net Contrast of a Model Codend on the Escapement of Juvenile Red Seabream Pagrus major

  • Kim, Yong-Hae;Whang, Dae-Sung
    • Fisheries and Aquatic Sciences
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    • v.14 no.2
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    • pp.130-137
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    • 2011
  • Visual stimuli of nets, which affect fishing selectivity, vary by twine diameter, color, and material under different light conditions and visual geometries. In this study, two cylindrical model codends of two mesh sizes, 28 and 43 mm, were made of high-contrast, dark brown polyethylene (PE) netting twine and low contrast, light-blue polyamid (PA) monofilament twine. Each model codend was filled with juvenile seabream and set in the water channel of a light-blue circular tank under a flow speed 0.8 m/s for 30 min. Light conditions were set to relatively bright, dim, and dark. The resulting retention rates of juvenile seabream were 15-35% lower for the low-contrast codend with PA monofilament than for the high contrast PE twine netting under bright and dim light conditions, while no difference was observed under dark conditions. The effects of mesh size and netting contrast on the retention rate were dependent on the light level, while the retention rate due to netting contrast was independent of mesh size. Therefore, low-contrast nets in the codend could help to reduce juvenile bycatch by disturbing the orderly optomotor response.

The Phenotype of the Soybean Disease-Lesion Mimic (dlm) Mutant is Light-Dependent and Associated with Chloroplast Function

  • Kim, Byo-Kyong;Kim, Young-Jin;Paek, Kyoung-Bee;Chung, Jong-Il;Kim, Jeong-Kook
    • The Plant Pathology Journal
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    • v.21 no.4
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    • pp.395-401
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    • 2005
  • The dlm (disease lesion mimic) mutant of soybean (Glycine max L. Merr) shows the similar lesion of a soybean disease caused by a fungus, Corynespora cassilcola. The lesion was examined at cellular and molecular level. Trypan blue staining result indicated that cell death was detectable in the entire region of leaves excluding veins when the lesions had already been developed. We found that the mesophyll cells of palisade layer in the dim mutant appeared to be wider apart from each other. The chloroplasts of the dim mutant cells contained bigger starch granules than those in normal plants. We also found that the lesion development of dlm plant was light-dependent and the starch degradation during the dark period of diurnal cycle was impaired in the mutant. Three soybean pathogenesis-related genes, PR-1a, PR-4, and PR-10, were examined for their expression patterns during the development of disease lesion mimic. The expression of all three genes was up-regulated to some extent upon the appearance of the disease lesion mimic. Although the exact function of DLM protein remains elusive, our data would provide some insight into mechanism underling the cell death associated with the dim mutation.

ZEEMAN'S THEOREM IN NONDECOMPOSABLE SPACES

  • Duma, Adrian
    • Journal of the Korean Mathematical Society
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    • v.34 no.2
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    • pp.265-277
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    • 1997
  • Let E be a real, non-degenerate, indefinite inner product space with dim $E \geq 3$. It is shown that any bijection of E which preserves the light cones is an affine map.

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Influence of Light Intensities on Clothing Behavior and Melatonin Secretion (조도의 차이가 의복착의행동 및 멜라토닌 분비에 미치는 영향)

  • Kim, Hee-Eun;Tokura, Hiromi
    • Fashion & Textile Research Journal
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    • v.6 no.5
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    • pp.613-617
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    • 2004
  • The intent of this study was to determine whether different light exposure could modify the clothing behavior in the evening cold environment or not. Nine female subjects volunteered to this study. In a bright light or a dim light condition, light intensity was controlled 3000 lx or 10 lx respectively. Subjects were introduced to wear various kinds of garments whenever they need to feel comfortable as the room temperature began to decrease. The room temperature was lowered from $30^{\circ}C$ to $15^{\circ}C$ for one hour (21:00 h~22:00 h) and maintained at $15^{\circ}C$ for additional one hour (22:00 h~23:00 h). Subjects stayed in chamber from 08:00 to the next day 07:00. Clothing behavior, core temperature, subjective temperature sensation and melatonin secretion were measured. Most subjects put on the clothing more quickly and more thickerly in the bright light rather than in the dim light condition. The fall of core temperature during night was significantly less under the bright light in the late afternoon, suggesting that the set-point of core temperature has been set at a higher level during the evening and the night, being supported by the less amount of melatonin secretion. Thus, it is concluded that the quicker dressing behavior with thicker clothing in the "Bright" condition is advantageous in evening cold exposure, since it enables the core temperature to reach its set-point value more easily.

Development of automatic illumination controller for energy saving (에너지 절약형 자동조명 장치 개발)

  • 최명호;강형곤;김민기;한병성
    • Electrical & Electronic Materials
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    • v.9 no.10
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    • pp.1027-1032
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    • 1996
  • The auto-illumination controller for office, residence, and so on was studied. The system consists of parts of a power supply, a signal oscillator, a lamp controller and two kinds of sensor. The lamp controller has two thyristors triggered by the IR sensor(SCRI) and CdS sensor(SCR2) respectively, When the illuminance around this system is higher than operating value of its sensor, lamp is turned off automatically. Otherwise, the light of lamp gets dim by CdS sensor. In case IR sensor senses the body heat of people around itself, the illuminance of the lamp gets maximum. The illuminance of the lamp can be changed dimmly by control of the variable resistor (RV) connected with SCR2 in series. The turning - on time of the lamp can be also controlled using a variable resistor(Rt) connected with a signal oscillator in parallel. Changing resistance Rt changes the time constant(.tau.), which triggers the gate of SCR2. Though people left the surrounding of lamp, the lamp keeps light for a while.

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