• Journal of Environmental Science International
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• v.8 no.2
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• pp.241-248
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• 1999

The photocatalytic decolorization and photodegradation of wastewater contamininated with dyes such as methyleneblue tetrahydrate(MBT), methyl orange(MO), phenol red(PR) and the mixed dyes have been studied using a batch reactor in the presence of aerotropic and titania. Degussa P25 titanium oxide was used as the photocatalyst and proved to be effective for the dyes-degradation when irradiated with UV-light source emitting the wavelength of 253.7 nm in the presence of air. In addition to removing the color from the wastewater, the photocatalytic reaction simultaneously reduced the COD and optical density which suggests that the dissolved organic compounds have been photooxidized. The reaction rate of disappearance of the dyes were measured as a function of the irradiation times. The photooxidative procedure of the aquatic solution have the first order reaction-kinetics. The rate constants were increased in the order of PR < MBT < $gL^{-1}-TiO_2$ powder were irradiated with the UV -light source.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.352-357
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• 2002

Some interaction characteristics, i.e., light scattering characteristics, of infrared (IR) radiation with small ice crystals are investigated systematically by using the exact T-matrix approach. Some important facts are obtained, which reveal, especially, that the combination of both the 25 and 3.979$\mu$m together has some advantages and potential applications for remote sensing of cirrus and other ice clouds. A new far-IR channel at the wavelength of 25$\mu$m is proposed.

• Proceedings of the Acoustical Society of Korea Conference
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• 1984.12a
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• pp.27-32
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• 1984

When chopped light inpinges on some condenced matters such as HgS, HgI2 and GaSe semiconductors, in an enclosed cell, the acoustic signals are produced within the cell. These acoustic signals were detected by using a gas-phase microphone in order to investigate the physical properties of the samples. In order to carry out investigation, PA-cell was first designed and made so as to produce higher sensitivity to acoustic signals. Second, an analysis of the photoacoustic spectrum of the various compounds was carried out to obtain the intensity of the PA-signal in terms of light wavelength and to calculate the energy band gaps occuring according to energy transitions. The agreement between the results obtained by this conventional PAS technique and the results obtained by the optical spectrum method was good. In additional analysis conducted on the basis of the R-G theory and the Sze theory are capable of determining the characteristics of energy transition of semiconductors.

• Korean Journal of Microbiology
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• v.20 no.1
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• pp.21-26
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• 1982

The disinfection effects of sunlight and predacious microorganisms on enteria of Escherichia coli and Proteus vulgaris were examined in sewage water at 22 to $26^{\circ}C$. The test prganisms were disinfected by 4 to 5 logs during 6-hour a day exposure to sunlight for seven days. The effect was proportional to the light intensity and was proved to be dur to the action of the visible light of short wavelength which can transmit the soft glass of a flask glass. The predacious microorganisms decreased trhe test organisms by about 3 to 4 logs during 7 days. The complex actions of sunlight and predacious microorganisms were variable depending upon the test organisms, but the total effects of those enviromental factors were yet completely understood.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.47-56
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• 2010

For a human being's smooth activity, the clean air and comfortable lighting environment are needed. The suitable lighting environment is obtained generally by making it available for being formed the bright situation easy for seeing object and the visually comfortable atmosphere. In this way, even the lighting environment was changed along with economic development. Even a light source was diversified. Thus, several kinds of new light sources such as LED, OLED, PLS, and CNT came to appear. Halogen lamp, which has low efficiency due to high color rendering among lamps of being used now, is being much used yet. However, owing to radiation of UV and IR, there are many limitations to the subject in general exhibition lighting, museum, and art museum. Accordingly, a research was performed on filter that is blocked UV and IR at the same time, by using halogen lamp that is excellent in color rendering and in life.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.22-26
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• 2007

In the fibre to the home (FTTH) era, it is expected that broadband network provisioning will require thousands of optical fibres to be accommodated in a central office for optical access networks. An optical fibre line testing system could be used to reduce maintenance costs and improve service availability depending on the PON's element manager capabilities and the maintenance procedures adopted by the network supplier. When monitoring optical fibres transmitting communication lights, a wavelength of 1625 nm is used for maintenance testing. The splitter installed optical filters allow the communication light to pass but that cut off the test light in the front of optical line terminals (OLTs) and optical network terminals (ONTs). In the economic point of view, We design new planer lightwave circuit splitter embedded filtter and study it optical property.

• International Journal of Automotive Technology
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• v.1 no.2
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• pp.89-94
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• 2000

As a promising catalyst reducing cold start emissions of automobiles, a photocatalyst systems has been studied. Since the photocatalyst is only activated by UV wavelength light, it needs no heat energy like a conventional TWC, therefore no light-off time. However, as a cold temperature catalyst to treat cold start emissions of a vehicle, previous studies on characteristic of photocatalyst have room for improvement in terms of performance and durability investigated from the viewpoints of performance and durability improvement. Eleven different coating samples were prepared with the combination of six kinds of additives and two kinds of photocatalyst materials. Then these samples were aged with a hydrothermal aging process. The performance of these samples was measured on a model gas apparatus with simulated exhaust gases. The durability was also analyzed with X-ray diffraction meter.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1823-1825
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• 2007

Based on Faraday effect, the variation of current flowing through the conductor can be encoded as that of azimuth angle of light polarization propagating through the fiber coil wound onto the conductor. The amount of current can be obtained by measuring the variation of the light intensity transformed from that of the azimuth angle through a polarization analyzer. In this paper we propose a fiber-optic current sensor system that employs a fiber polarization analyzer as a sensor interrogation device. The fiber polarization analyzer was prepared by inscribing a long-period fiber grating on a high birefringent fiber. At the fixed wavelength of 1522.5 nm, the fabricated fiber device has the polarization extinction ratio of more than 25 dB. The measurement of large current up to 600 Arms was accomplished based on a simple fiber interrogation device and the measurement output of the sensor system showed a good linearity.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.147-149
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• 1999

Biotransformation of exogenous (-)-(4R)-isopiperitenone in cell suspension cultures of Mentha piperita resulted in oxidized products, with (-)-7-hydroxyisopiperitenone being the major compound. The mass of products obtained $unde^{18}O_2$, atmosphere was two units higher than that under normal atmosphere. The biotransformation was inhibited by several cytochrome P450-specific inhibitors as well as by carbon monoxide. Carbon monooxide inhibition was substantially overcome by irradiation of cells with blue light including light at 450nm wavelength. These results suggested that a cytochrome P450-type monooxygenase was involved in the biotransformation.

• Journal of the Korean Applied Science and Technology
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• v.23 no.1
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• pp.70-76
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• 2006

The influence of fluorophor, scatterer, absorber in turbid materials by light scattering were interpreted for the scattered fluorescence intensity and wavelength, it is studied the molecular property by laser induced fluorescence spectroscopy. It can be found that the effects of optical property are penentrated in scattering media by the optical $parameters({\mu}s$, ${\mu}a$, ${\mu}t$, ${\gamma}$, ${\rho})$. The value of scattering coefficient ${\mu}s$ is large appeared by means of the increasing particles of scattering, it can be found that the slope appears exponentially as a function of distance from laser source to detector. It may also utilize in designing the best model for oil chemistry, laser medicine and application of medical engineering.