• Laser Solutions
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• v.18 no.3
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• pp.14-19
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• 2015

A helical fabricating method using $CO_2$ laser was utilized for producing cone-shaped structure on a silica substrate. Output power and the number of scanning radiation were modified in order to control the structure. The experiment shows that the depth and width of cone-shape were increased with higher output power of the laser and the number of scanning. We demonstrate fabrication of multidirectional side-firing optical fiber with diameter of 440 um using the $CO_2$ laser fabrication technique.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1773-1777
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• 2010

The Application of UV curing technique for poly (vinyl chloride) (PVC) floor tiles coating has improved the quality of PVC floor. Several formulations were made including acrylated oligomers based on a polyurethane were blended with reactive monomers, photoinitiators and other additives. The used oligomers are commercial aliphatic urethane acrylates. Thin films were prepared on PVC tiles by bar coating with different formulations using UV radiation. The coating resins were characterized by FTIR. The properties of UV-cured films such as gloss and adhesion were examined. The properties of UV-cured films dependent on the influence of composition and processing conditions was studied.

• Korean Journal of Head & Neck Oncology
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• v.4 no.1
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• pp.13-19
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• 1988

Brachytherapy is known to be a good modality to achieve local control as a boost treatment following limited external irradiation, which may reduce the external beam related acute radiation sickness, particularly in head and neck cancer. The authors developed iridium-192 ribbons recently to replace the radium needles. Total of 13 head and neck cancer patients had been treated with Ir-192 ribbons during last one year from October 1986 to September 1987, and the results were analysed to assess the applicability of the fabricated sources. The conclusion is as follows; 1) Iridium implant achieved 54% (7/13) of complete response and 69% (9/13) of overall response rate in head and neck cancer. 2) Iridium is superior to radium and cecium in brachytherapy because of easier to use and lesser exposure to the personnel. 3) Afterloading technique is useful to modify dose distribution, to expand treatment site and method, and to develop interstitial hyperthermia.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.113-115
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• 2001

In order to design the power appratus such ac bus bar, the current carrying ampacity should be determined, Since it is limited by maxium operating temperature, it is very important to predict temperature-rise on it. The main causes to raise temperature are joule's loss in the current carrying conductor and induced circulating and eddy current in the tank. The heat transfer is divided into convection and radiation on boundary, determining convection heat transfer coefficient is not easy. This paper propose a new technique that can be used to estimate the temperature rise in the extra high voltage bus bar. The heat transfer coefficient is analytically calculated by applying Nusselt Number depending on temperature as well as model geometry. The analytic method which use heat transfer coefficient is coupled with finite element method. The temperature distribution in the bus bar by the proposed method shows good agreement with experimental data.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.77-81
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• 2006

We report the performance of a four-element, 11.67 GHz, high-Tc superconducting (HTS) microstrip antenna array with corporate feed network and circular polarization for direct broadcasting satellite (DBS) system. Our array antennas were designed and built on a 0.5 mm thick MgO substrate. To compare the superconducting antennas with normal conducting counterpart, One antenna pattern was fabricated from gold thin film, and a second pattern was fabricated from $YBa_2Cu_3O_{7-x}$ (YBCO) superconducting thin film. To improve the axial ratio of circularly polarized arrays, sequential rotation technique were used. Efficiency, radiation pattern, return loss and bandwidth were measured for both antennas at room temperature and at cryogenic temperature. The array produced good circular polarization, and the gain of the array at 77 K, relative to a copper array at room temperature was approximately 1.54 dB. The measured return loss of our HTS antenna array was 35.79 dB at the resonant frequency of 11.67 GHz and The total effective bandwidth was about 3.4 %. The results showed that high-temperature superconductors, when used in microstrip arrays, improved the efficiency of the HTS antenna array for circularly polarization.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.675-676
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• 2006

This paper shows the temperature rise of the high voltage GIS bus bar. The temperature rise in GIS bus bar is due to Joule's losses in the conductor and the induced eddy current in the tank. The power losses of a bus bar calculated from the magnetic field analysis are used as the input data for the thermal analysis to predict the temperature. The required analysis is a couple-field Multiphysics that accounts for the interactions between three-dimensional AC harmonic magnetic and fluid fields. The heat transfer calculation using the fluid analysis is done by considering the natural convection and the radiation from the tank to the atmosphere. Consequently, because temperature distributions by couple-field Multiphysics (coupled magnetic-fluid) have good agreement with results of temperature rise test, the proposed couple-field Multiphysics technique is likely to be used in a conduction design of the single-pole and three pole-encapsulated bus bar in CIS..

• Proceedings of the Plant Resources Society of Korea Conference
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• 1999.10a
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• pp.58-64
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• 1999

As indicated by Chinese letters "사혁" (sha-ji) is the ripe fruit of Seabuckthron (Hippophae rhamnoides Linneus) Family Flaeagnaceae is one of ancient natural medicine used by the Tibetan and Mongolian nationallites with ancient methods to treat desease, It is an effectiv Traditional Tibetan medicine. Bud only now are they beginning to be understood in the world of modern medicine. Hippophae was written in the book of Traditional Tibetan Medicine - "Somalaza" (8th century), "Sibuyidian" (1840) and "Jingzhubencao" (Qing Dynasty). The "Sibuyidien" was trnslated in to the Russian and published at 1903 in the Russian. Then the Russian bigan to study on Hippophae and they have achieved great successes. The Chinese scientists began to study on the chemical constituent and medical action with modern technique at 1952. With more than 40 years painstaking eport they have conceived and used a wide variety of experimental screening systems, achieved successes. Finally the)1 with one's own tests has keen verified that the crude drug being various kind of bioactive substance could Inhibits tumor, increase immunity, wipe out free radical, prevent disease of cardiovascular system, have anti-radiation, anti-inflammeutory effects. At 1977 the Hippophae rhamnoides was written in Chinase Pharmacopoeia.e rhamnoides was written in Chinase Pharmacopoeia.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.74-79
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• 2011

Concentration characteristics of the KIER solar furnace are analyzed with a heat flux measurement technique. Total heat capacity of 40kW was confirmed within 1.04% average error, and the normalized maximum heat flux of 3,452 $kW/m^2$ was proved. Non-Gaussian flux distribution in the vertical direction implies that reflectors should not be random rather inclined downwards. Moreover, we characterized flux distribution variations with furnace blind opening ratio, distance from the focal plane, and misalignment of the measurement system. Based on the results, the heat flux distribution can be simply estimated once reflectivity and direct normal insolation values are known. This study will be helpful to the design and the performance evaluation of receivers or chemical reactors.

• 전자공학회논문지 IE
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• v.48 no.3
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• pp.10-15
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• 2011

In the case of designing an acoustic transducer for high power application, we usually aim to transfer the source electric energy to the output acoustic energy as large as possible. For this purpose, we should match the impedance of the power amplifier to the impedance combined with the acoustic transducer impedance and the radiation impedance. Especially if we have electrical source with almost zero impedance, we need improve the power factor of the acoustic transducer in the load. In this paper, we propose a broad band impedance matching method by the improvement of power factor, which applies ABCD matrix.

• The Microorganisms and Industry
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• v.15 no.1
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• pp.38-42
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• 1989

Industrial strain Improvement is concerned with developing or modifying microorga-nisms used In production of commercially important fermentation products. The aim is to reduce the production cost by improving productivity of a strain and manipulating specific cilarafteristic such as the ability to utilize cheaper raw materials or resist bacteriophages. The traditional empiri-cal approach to strain improvement is mutation combined with selection and breeding techniques. It is still used by us to improve the productivity of organisms in amino acids. organic acids andenzymes production. The breeding of high L-lysine-producing strain Au112 is one of the outstanding examples of this approach. It is it homoserine auxotroph with AEC, TA double metabolicanalogue resistant markers. The yield reaches 100g/1. Resides, the citric acid-producing organism Aspergillus nuger, Co827, its productivity reches the advanced level in the world, is also the result of a series mutations expecially with Co Y-radiation. The thermostable a-amylaseroducing strain A 4041 is the third example. By combining physical and chemical multations. the strain ,A 4041becomes an asporogenous, catabolite derepressed mutant with rifamycin resistant and methionine, arginine auxotroph markers. The a-amylase activity reaches 200 units/ml. The fourth successful example of mutation in strain improvement is the glucoamylase-producing strain Aspergillus nigerSP56 its enzyme activity is 20,000 units/ml, 4 times of that of the parental strain UV_11. Recently recombinant DNA approach Provides a worth while alternative strategy to Industrial strain improve-ment. This technique had been used by us to increase the thermostable a-amylase production and on some genetic researches.