• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.108-111
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• 2001

ZnO thin films on (001) sapphire substrates knave been deposited by pulsed laser deposition(PLD) technique for light emitting device applications. We have controlled the emission intensity of UV and visible light, depending on film thickness and various post-annealing time. UV emission became strong as the thickness of ZnO thin films increased. The intensity of visible light was strong as post-annealing temperature increased. The optical properties of the ZnO thin films were characterized by PL(photoluminescence) and the structural properties of the ZnO were characterized by XRD for the application of ZnO light emission device.

• Current Optics and Photonics
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• v.3 no.5
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• pp.408-414
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• 2019

In this paper we propose a method to generate a true color image in scanning white-light interferometry (SWLI). Previously, a true color image was obtained by using a color camera, or an RGB multichannel light source. Here we focused on acquiring a true color image without any hardware changes in basic SWLI, in which a monochrome camera is utilized. A Fourier transform method was used to obtain the spectral intensity distributions of the light reflected from the sample. RGB filtering was applied to the intensity distributions, to determine RGB values from the spectral intensity. Through color corrections, a true color image was generated from the RGB values. The image generated by the proposed method was verified on the basis of the RGB distance and peak signal-to-noise ratio analysis for its effectiveness.

• Korean Journal of Ichthyology
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• v.19 no.3
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• pp.185-192
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• 2007

The present experiment was carried out to study the effects of light intensity on growth, survival, caudal fin shape, body composition, skin color and blood component of river puffer, Takifugu obscurus. Four light intensities (0, 500, 1,000, 2,000 lx) were tested in duplicates for 60 days. Specific growth rate (SGR), daily feeding rate (FR) and food coefficient (FC) were reduced following to the decrease of light intensity. However in survival rate there was not significantly different among groups. The damage extent of caudal fin was increased in more strong light intensity. In body composition, moisture and crude protein were only significantly difference according to light intensity. In body color, L and a were the highest in 0 lx. In blood analysis, the content of AST, ALT, GLU significantly increased in more powerful the intensity groups. It is concluded that the supplement of low light intensity (e.g. 0 lx) recommended for the commercial scale aquaculture of river puffer in land-based tank without growth and survival retardation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.9
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• pp.708-713
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• 2010

In this research a ring light was developed so that a partial shadowless shooting for the patient's affected area at the medical treatment room and surgical operation room using high luminance light emitting diode (LED) for which attention is being paid as new lighting parts for medical purpose. LED which was applied to the development used high luminance three color LED for full color for which various color materialization and the adjustment of radiation intensity are possible and we can get white light in order to emphasize the delicate expression for generic tone of shooting object, strong highlight, simple shadow and three dimensional effect at the time of close-up shadowless shooting of the affected area. And at the time of design of ring light, the characteristics of LED and the loss of light at the time of penetrating light diffusion PC were considered so that intensity of illumination for over 150 lx can be obtained. The result of measurement of the intensity of illumination of the ring light that was developed revealed that maximum intensity of illumination of 225.7 lx was obtained, while smoke index was measured to be maximum 78 Ra in the case of Red(50%) Green(100%) and Blue LED(60%). We could confirm that response speed was also very fast as 1.72 ms.

• Applied Biological Chemistry
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• v.29 no.4
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• pp.366-371
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• 1986

Fatty acid compositions of Panax ginseng leaves (6 year) grown under different light intensity in field and of the detached leaves exposed to high temperature (20 hours) were investigated by gas chromatography. Linoleic, linolenic, palmitic and palmitoleic acid were the major components(80%) of leaf lipid. The higher the growth light intensity, the lower the percentage of unsaturated acids or bonds, indicating metabolic adaptation to high temperature. Pattern similarity of fatty acid composition was little changed until 20% light but significantly different at 30%, suggesting 20% as limitation light intensity. The close similarity of fatty acid composition between the loaves grown under 30% light and the one at harvest rises uncertainty between adaptation to high temperature and senescence. Total fatty acid content decreased with the increase of light intensity. Short term high temperature $(25^{\circ}C\;or\;35^{\circ}C)$ increased total fatty acid content, unsaturated acid percentage and insignificant difference in pattern similarity of composition.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1383-1388
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• 2011

Due to many recent activities on enforcement of the intensified environmental regulation such as the policies of curbing the greenhouse gas and the Restriction of Hazardous Substances (RoHS), the usage of Light emitting diode (LED) has been rapidly increased and energy efficient management of LED light system is regarded as an important technology to enhance the energy efficiency. In this paper, we propose an energy-efficient control scheme of LED light, being composed of multiple light sources. The proposed scheme controls the intensity of LED light source to minimize the total intensity while providing the quality of lighting service. The intensity of light is assumed to be proportional to power consumption, thus the objective is to minimize the total power consumption. A linear programming problem is formulated to find the optimal intensity of each light source and procedure to apply the proposed scheme in the real system is suggested. The performance evaluation results elucidate that the proposed scheme achieves over 20% improvement in power consumption of light intensity in comparison with the conventional dimming control scheme.

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.442-449
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• 2004

Improving the light utilization efficiency of photosynthetic cells in photobioreactors (PBRs) is a major topic in algal biotechnology. Accordingly, in the current study we investigated the effect and suitability of photosynthetic pigment reduction for improving light utilization efficiency. The light-harvesting complex II (LH-II) genes of Rhodobacter sphaeroides were removed to construct a mutant strain with less pigment content. The mutant strain exhibited a slower growth rate than the wild-type under a low light intensity, while the mutant grew faster under a high light intensity. In addition, the specific absorption coefficient was lower in the mutant due to its reduced pigment content, thus it seemed that light penetrated deeper into its culture broth. However, the distance (light penetration depth) from the surface of the PBR to the compensation point did not increase, due to an increase in the compensation irradiance of the mutant strain. Experimental data showed that a reduced photosynthetic pigment content, which lessened the photoinhibition under high-intensity light, helped the volumetric productivity of photosynthetic microorganisms.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.586.2-586
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• 2001

The selection of a curing light is a multifactorial decision. While each method of polymerization presents unique clinical benefits, the optimal light-curing technique remains to be determined. The objective of this study was to check the difference of micro hardness and microleakage according to various light intensity (50, 100, 200, 300, 400, 600 ㎽/$\textrm{cm}^2$) and curing time (10, 20, 40 seconds). A3 color of two composite resin, hybrid type DenFil and submicron type Esthet X were tested.(중략)

• Journal of information and communication convergence engineering
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• v.11 no.4
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• pp.247-252
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• 2013

An intelligent light emitting diode (LED) dimming system is designed and implemented for energy-saving lighting systems. An LED light bulb is powered by an LED driver controlled by a microcontroller using pulse width modulation (PWM) signals. By changing the duty cycle of the PWM signals, the LED driver generates a driving current of up to 1,000 mA. The current consumption by the LED light bulb exhibits a very linear characteristic that indicates that the level of LED dimming can be finely tuned. Multiple sensors-lighting intensity and ultrasonic range sensors-are combined with the LED dimming system to realize an automatically controllable LED lighting system. The light intensity sensor is capable of sensing ambient light. The ultrasonic range sensor can detect objects from 0.15 to 5.6 m at a resolution of 0.0254 m. The collected information by the light intensity and ultrasonic range sensors is processed by the microcontroller that in turn automatically controls the brightness of the LED light bulb. The algorithm of the software for the LED dimming system is also described.

• Journal of Urban Science
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• v.8 no.2
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• pp.29-34
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• 2019

Benzene pollution is becoming increasingly serious, and the treatment technology of benzene has attracted much attention. In this paper, a self-made photocatalytic reactor was used to explore the removal rate of benzene under the ultraviolet light with the wavelength of 253.7nm. The results showed that the degradation rate of benzene decreased from 64.29% to 16.26% when the concentration increased from 43mg/㎥ to 256mg/㎥ under the condition of 28W UV light intensity and 50s residence time. Under the condition of 28W UV light intensity and 103mg/㎥ concentration, the residence time increased from 16.5s to 50s, and the benzene removal rate increased from 13.23% to 42.72%.Under the condition of benzene concentration 103mg/㎥ and residence time of 50s, the removal rate of benzene increased from 29.34% to 52.58% in the process of UV light intensity rising from 28W to 48W.It is concluded that decreasing the concentration and increasing the residence time of gas were beneficial to the removal of benzene and increasing the light intensity can improve the removal rate of benzene.