• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.265-274
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• 2016

In this study, the system was composed of the booster chopper and the power converter, which is a pulse width modulation (PWM) voltage inverter using a hybrid power generation system solar cell energy and wind force, Furthermore, in order to compensate the PWM voltage type inverter was linked with the general commercial power source, and through a normal operation of energy storage system (ESS), the system operated the LED Taxi Light by Wavelength according to Meteorological Changes at the airport in an efficient manner. The performance of the system was compared with the solar cell characteristics specification. In addition, for phase synchronization with the PWM voltage type inverter, the grid voltage was detected so as to operate the grid voltage and inverter output in the same phase and to connect the surplus electric power with the system. Finally, by developing a control circuit at the same time from which an excellent dynamic characteristics can be obtained through applying to the airport runway taxi light, it was concluded that a variety of taxi light can be pursued.

• Journal of Mushroom
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• v.18 no.1
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• pp.10-19
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• 2020

Light is an important factor for cordycepin production in Cordyceps militaris. We investigated the effects of different light-emitting diode (LED) conditions including various LED wavelengths and their combinations on cordycepin production in Cordyceps militaris cultivated in submerged culture. The results of our study showed that the combinations of LED wavelengths were more beneficial than single LED sources for cordycepin production. Among the three tested wavelength combinations, the greatest effects for cordycepin production were observed for the red:blue light combination at the wavelength ratio of 5:5 or 3:7. The optimal culture conditions were 19.2278 h/day of illumination time; 9.19497 g/50 mL of glucose content in the media; and 53.112 h of cultivation time. Our model predicted a maximum yield of 2860.01 ㎍/mL cordycepin. Finally, to verify the calculated maximum, we performed experiments in the culture media representing the obtained optimum combination and the cordycepin yield of 2412.5 ㎍/mL.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.1
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• pp.36-43
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• 2023

To establish a culture system with enhanced cellular nutrition, we investigated the effects of light quality (blue, 450 nm; yellow, 590 nm; and red, 630 nm) of a light-emitting diode (LED) on the biochemical composition of Tetraselmis suecica and T. tetrathele. The protein content of both species was higher (42-69%) than the content of other biochemical substances under all wavelengths. Carbohydrate, protein, and lipid contents were higher under the yellow wavelength, which showed a low growth rate, than those under other wavelengths. The contents of all biochemical substances were low under the red wavelength, which showed a high growth rate. These results indicated that protein synthesis occurs in response to decreased cell division rate, while lipid and carbohydrate synthesis occurs owing to altered chemical composition and enzymatic activity. Therefore, we suggested a two-phase LED culture system, which emitted red LED during the early-middle exponential phase and yellow LED during the late exponential and stationary phases, to increase the yield of useful biochemical substances of T. suecica and T. tetrathele.

• Journal of the Korea Computer Graphics Society
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• v.16 no.2
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• pp.39-45
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• 2010

The color of object is a main role that people recognize outdoor entity with its shape. We can perceive the object due to the existence of light such as direct sunlight. Light is classified by wavelength into radio, microwave, infrared, the visible region we perceive as light, ultraviolet, X-rays and gamma rays. White light is all of the colors of light combined within the visible light spectrum. When white light is separated through a prism, we see the visible light spectrum. The various wavelengths of visible light are separated into colors. In this paper, we construct white light as the seven colors of rainbow and suggest the method of N-way color dispersion photon mapping to simulate the natural dispersion phenomenon.

• Journal of Internet Computing and Services
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• v.25 no.4
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• pp.65-72
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• 2024

To faithfully represent the intention of the work in the exhibition space, lighting that provides high color reproduction like natural light is required. Thus, many lighting technologies have been introduced to improve CRI, but most of them only evaluated the general color rendering index (CRI Ra), which considers eight pastel colors. Natural light provides excellent color rendering performance for all colors, including red and blue, expressed by color rendering index of R9 and R12, but most artificial lighting has the problem that color rendering performance such as R9 and R12 is significantly lower than that of natural light. Recently, lighting technology that provides CRI at the level of natural light is required to realistically express the colors of works including primary colors but related research is very insufficient. Therefore this paper proposes exhibition hall lighting that fulfills CRI with a focus on CRI Ra, R9, and R12 based on the characteristics of natural light. First reinforcement wavelength bands for improving R9 and R12 are selected through analysis of the actual measurement SPD of natural and artificial lighting. Afterward virtual SPDs with a peak wavelength within the reinforcement wavelength band are created and then SPD combination conditions that satisfy CRI Ra≥95, R9, and R12≥90 are derived through combination simulation with a commercial LED light source. Through this, after specifying two types of light sources with 405,630nm peak wavelength that had the greatest impact on the improvement of R9 and R12, the exhibition hall lighting applied with two W/C White LEDs is designed and a control Index DB of the lighting is constructed. Afterward experiments with the proposed method showed that it was possible to achieve high CRI at the level of natural light with average CRI Ra 96.5, R9 96.2, and R12 94.0 under the conditions of illuminance (300-1,000 Lux) and color temperature (3,000-5,000K).

• Journal of Photoscience
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• v.7 no.3
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• pp.79-86
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• 2000

Phytochromes are red and far-red light absorbing photoreceptors for photomorphogenesis in plants. The red/far wavelength reversible biliproteins are made up of two structural domains. The light-perceiving function of the photoreceptor resides in the N-terminal domain, whereas the signal transducing regulatory function is located within the C-terminal domain. The characteristic role of the phytochromes as phtosensory molecular switches is derived from the phototransformation between two distinct spectral forms, the red light absorbing Pr and the far-red light absorbing Pfr forms. The photoinduced Pr Pfr phototransformation accompanies subtle conformational changes throughout the phytochrome molecule. The conformational signals are subsequently transmitted to the C-terminal domain through various inter-domain crosstalks and induce the interaction of the activated C-terminal domain with phytochrome interacting factors. Thus the inter-domain crosstalks play critical roles in the photoactivation of the phytochromes. Posttranslational modifications, such as the phosphorylation of Ser-598, are also involved in this process through conformational changes and by modulating inter-domain signaling.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.1-1
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• 2000

The interaction of light with periodic patterns generates beautiful color patterns and interesting applications. The basic equation for understanding this phenomena is the grating equation. It tells us the angles, relative to a perpendicular to a grating with a specific period, into which light of a specific wavelength will be diffracted. But what it does not tell us is how much light will be directed into the various "orders" of the grating. It was found that by controlling the shape of the diamond point used to cut the periodic structure into the substrate, a traditional grating could be made to direct most of the light diffracted from it into a single order. This type of grating is referred to as a "blazed" grating. (omitted); grating. (omitted)

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.459.1-459.1
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• 2014

Because both $TiO_2$ and ZnO has superior characteristic optically and electrically, there are various of research for these materials. However, they have large band gap energy which correspond with not visible light, but UV light. To make up for this disadvantage, Quantum dots (CdS, CdSe) which can absorb the visible light could be deposited on $ZnO/TiO_2$ nanostructure so that the the photoelectrochecmical cell can absorb the light that has larger region of wavelength. Both $TiO_2$ and ZnO can be grown to one-dimensional nanowire structure at low temperature through solutional method. Three-dimensional hierarcical $ZnO/TiO_2$ nanostructure is fabricated by applying these process. Large surface area of this structure make the light absorbed more efficiently. Through type 2 like-cascade energy band structure of nanostructure, the efficient separation of electron-hole pairs is expected. Photoelectrochemical charateristics are found by using these nanostructure to photoelectrode.

• Journal of Conservation Science
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• v.36 no.4
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• pp.236-243
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• 2020

In this study, an accelerated aging experiment for fabric and paper was conducted using two light emitting diode(LED) sources with different wavelength characteristics, and the discoloration under each lighting type was examined. Hanji(Korean traditional paper) and related textiles showed more discoloration under blue LEDs, while the blue wool standard showed more discoloration under white LEDs. This, indicated that the deterioration varied depending on the sample color. The the effect of the light source on artifact deterioration was primarily related to the total radiation flux(expressed in mill watts), rather than the total luminous flux(expressed in lumens). In addition, the discoloration of the investigated artifacts was dependent on the color rendering of the lighting.

• Journal of the Optical Society of Korea
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• v.20 no.3
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• pp.401-406
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• 2016

This study first proposes a new version of a photonic crystal based de-multiplexer operating under the slow light regime, secondly analyses the structure numerically to demonstrate de-multiplexing operation and finally studies the impact of light speed on the performance of the proposed structure. The operation wavelength is 1.55 µm. The study indicates that, by adjusting the speed of light, around 0.1C, in the main waveguide and in the output channels’ waveguides, an enhancement in the performance of the de-multiplexer will be gained.