• Polymer(Korea)
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• v.26 no.2
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• pp.193-199
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• 2002

The dichloro-polyester polyol (DCBAO) which was synthesized in our earlier work was cured at room temperature with two different type of curing agents including Desmodur N-3300 and Desmodur L-75 to get a polyurethane flame-retardant coatings (DCBAO/N-3300=DEBAN and DCBAO/L-75=DCBAL). We could not observe any deterioration of physical properties of the flame-retardant PU coatings (UCBAN and DCBAL) in comparison with the conventional PU coatings. Thermal resistance of DCBAL-type flame-retardant coatings, which was measured by yellowness index difference, was inferior to that of DCBAL-type PU coatings. We believe that this phenomena is attributed to the poor thermal resistance of Desmodur L-75 isocyanate. It was observed that the LOI values were 25∼26% for the PU coatings containing 20∼30 wt% of 2,4-dichlorobenzoic acid.

• Economic and Environmental Geology
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• v.51 no.3
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• pp.213-222
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• 2018

Metasediment-hosted Pb-Zn mineralized zone has been found in Dyusembay of Kazakhstan. Its petrological properties, metal index, alteration index and redox-sensitivity are compared with those of SEDEX type deposit. Mineralization is developed along foliation of host rock (graphitic phyllite) and controlled by folds and faults; major ore minerals including pyrite, pyrrhotite, sphalerite, and galena are disseminated or interlayered with fine-grained quartz. The margin of the mineralized zone is metamorphosed accompanying sericite and chlorite. Hydrothermal brecciation and Pb-Zn mineralization formed in quartz-calcite stockworks are confirmed at the around of Maytyubin granitoid intrusions. The mineralization is classified into three types according to those of occurrence, paragenesis, chemical composition and isotopic characteristics. Type 1 whose fine-grained pyrite, pyrrhotite and sphalerite are formed in parallel yet discontinuous to well-developed foliations of the host rock; its geochemistry is similar to those of the earlier stage in SEDEX-type mineralization. In case of type 2, the ore minerals of which are concentrated being parallel to a foliation by regional metamorphism, and most of them associated with quartz and muscovite (${\pm}$ biotite) paragenetically. Type 3 is formed in the hydrothermal breccia zone whose ore minerals are controlled by foliation and breccia and developed in quartz ${\pm}$ calcite veins having a form such as stratification, stockwork or veinlets. Host rocks in the mineralized zone indicate homogeneous metamorphic grade and there is no specific alteration zonation. Also, all types (type 1, type 2, and type 3) represent similar REEs patterns, it can be interpreted that these are originated from a same source. Sulphides occurred in mineralized zone indicate a limited range of sulphur isotope values (type 2, ${\delta}^{34}S=-13.3{\sim}-11.7$‰; type 3, ${\delta}^{34}S=-13.9{\sim}-8.2$‰), and a result of geothermometry presents different temperature ranges: type 2($251{\pm}38^{\circ}C{\sim}277{\pm}40^{\circ}C$); type 3($360{\pm}2^{\circ}C$ to $537{\pm}29^{\circ}C$). It is estimated to be due to the effect of metamorphism and Maytyubin granitoid intrusions, respectively. In addition, ternary chart of thorium, scandium, and zircon for discrimination of tectonic setting and redox sensitivity using V/Mo values indicate that hydrothermal sediments put on reduction environment after precipitation, before being affected by metamorphism and intrusion activity. Geochemical data are plotted on a distal trend of SEDEX-type with discrimination plot using SEDEX index. As a result, petrological-geochemical properties demonstrate that Dyusembay Pb-Zn mineralized zone is comparable to distal-type of SEDEX deposit.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.156-159
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• 2000

A new analysis method of Tap-Off for CATV, DBS, CS systems was proposed and investigated by using 4-port and Lport equivalent circuits. As an analysis method the even$.$odd-mode theory for a symmetrical coupled-line directional coupler was introduced, and then it was applied to transformer type directional couple By comparing the results of simulation and measurement, the validity of the proposed analysis method was confirmed. Furthermore, the Tap-off has been broadened from 5 MHz to 4,000 MHz by adopting the propose theory.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.1114-1115
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• 2023

이 논문은 해양 안전 및 보트 운항 훈련을 위한 소형선박 시뮬레이터의 개발을 다룬다. 시뮬레이터는 자유 운항, 시험 모드 운항, 초급자 훈련 모드 운항 등 다양한 기능을 제공하며, 사용자의 실력과 선호도에 따라 맞춤 교육을 제공한다. 이를 통해 보트 운항의 안전성을 향상시키고, 비용 효율적인 방법으로 많은 사용자들에게 접근 가능한 학습 도구를 제공한다.

• Economic and Environmental Geology
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• v.51 no.6
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• pp.493-507
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• 2018

The Wooseok deposit in Jecheon belongs to the Hwanggangri Mineralized Distict of the northeastern Ogcheon Metamorphic Belt. Its geology consists mostly of limestone of the Choseon Supergroup and the Cretaceous Muamsa granite intruded at the eastern area of the deposit. The deposit shows vertical occurrence of skarn and hydrothermal vein ores with W-Mo-Fe and Cu-Pb-Zn mineralization and skarn is developed only at lower levels of the deposit. Skarn minerals are replaced or cut by ore minerals in paragenetic sequence of magnetite-hematite, molybdenite-scheelite-wollframite, and higher abundances of pyrrhotite-chalcopyrite-pyrite-sphalerite-galena. Garnet has chemical compositions of $Ad_{65.9-97.8}Gr_{0.3-32.0}Pyr_{0.9-3.0}$, corresponding to andradite series, and pyroxene compositions are $Hd_{4.5-49.7}Di_{42.3-93.9}Jo_{0.5-7.9}$, prevailing in diopside compositions, both of which suggest oxidized conditions of skarnization. On the FeS-MnS-CdS ternary diagram, FeS contents of sphalerite in vein ores decrease with increasing MnS contents from bottom to top levels, possibly relating to W mineralization in deep and Pb-Zn mineralization in shallow level. Sulfur isotope values of sulfide minerals range from 5.1 to 6.8‰, reflecting magmatic sulfur affected by host rocks. W-Mo skarn and Pb-Zn vein mineralization in the Wooseok deposit were established by spatio-temporal variation of decreasing temperature and oxygen fugacity with increasing sulfur fugacity from bottom to top levels.

• Conservation Science in Museum
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• v.27
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• pp.91-102
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• 2022

Silica-based inorganic fillers for restoration of iron objects have been used for the reduction of thermal expansivity and the improvement of melt flow index. However, the higher the amount of filler is applied, the more degradation of mechanical properties and the yellowing occur, which could cause retreatment of the objects with adding stress to them. Thus, research on not only the quantification of a mixture of resin and filler but also the yellowing should be emphasized. Experiments on mechanical properties were carried out with a silica-based light filler, Micro Shell as a comparison group. The results of the experiment showed Micro Shell reduced the number of occurrences of the yellowing by 34% compared to existing fillers. The value of adhesion and specific gravity was also improved depending on the filler amount. The results of this research indicate the possibility of using Micro Shell as a new filler.

• Economic and Environmental Geology
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• v.46 no.2
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• pp.153-163
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• 2013

The Ogcheon Au-Ag deposit consists of two quartz veins that fill the NE or NW-trending fissures in the metasedimentary rocks of unknown age. The quartz veins occur mainly in the massive type with partially breccia and cavity. They can be found along the strike for about minimum 50 m and varied in thickness from 0.1 to 0.3 m. The mineralogy of quartz veins from the Ogcheon deposit is mainly composed of hydrothermal alteration minerals such as pyrite, quartz, sericite, chlorite, clay minerals and sulfides including pyrite, pyrrhotite, arsenopyrite, sphalerite, chalcopyrite and galena. Fluid inclusion data from quartz indicate that homogenization temperatures and salinity of mineralization range from 184 to $362^{\circ}C$ and from 0.0 to 6.6 wt.% eq. NaCl, respectively. These suggest that ore forming fluids were progressively cooled and diluted from mixing with meteoric water. Sulfur(${\delta}^{34}S$: 0.4~8.4‰) isotope composition indicates that ore sulfur was derived from mainly magmatic source although there is a partial derivation from the host rocks. The calculated oxygen(${\delta}^{18}O$: 4.9~12.1‰) and hydrogen(${\delta}D$: -92~-74‰) isotope compositions suggest that magmatic and meteoric ore fluids were equally important for the formation of the Ogcheon deposit and then overlapped to some degree with another type of meteoric water during mineralization.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.346-351
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• 2001

A new analysis method was proposed, where the even . odd-mode theory for a symmetrical coupled-line directional coupler was applied to a transformer-type directional coupler. In addition, the tap-offs were analyzed by the proposed theory, which are widely used in CATV (Cable Television), DBS (Direct Broad- casting Satellite), CS (Communication Satellite) systems. By comparing the calculation results to the measured ones using the even . odd-mode reflection coefficients only, the validity of the proposed analysis method was confirmed. Then, the tap-off has been broadened from 5 MHz over 4,000 MHz by adopting the proposed theory.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.12
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• pp.22-31
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• 2000

A new analysis method of Tap-011 for CATV and DBS systems was proposed and investigated by using 4-port and 3-port equivalent circuits. As an analysis method the even odd-mode theory for a symmetrical coupled-line directional coupler was introduced, and then it was applied to transformer type directional coupler. By comparing the results of simulation and measurement, the validity of the proposed analysis method was confirmed. Furthermore, the Tap-off has been broadened from 5 MHz to 2.500 MHz by adopting the proposed theory.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.4
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• pp.980-990
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• 2003

The effect of Gamigyuibi-tang on the penile erection induced by apomorphine HCI and on the erectile dysfunction induced by p,p-DDE, an environmental hormone derivate of DOT, were monitored using male cats. The changes of penile length, diameter, erectic periods and histological profiles of corpus cavernosum and corpus spongiosum were observed with blood testosterone levels. In conclusion, dose-dependent and significant increase of penile length, diameter, erectic periods and blood testosterone levels were detected in the Gamigyuibitang-dosing groups compared to other groups. In addition, it is also demonstrated that the increasement of congestion of blood vessels and dilation of connective tissues, and decreasement of adipocytes in the corpus cavernosum and/or corpus spongiosum of the Gamigyuibitang-dosing groups. According to these results, it is considered that Gamigyuibitang has some augmentation effect against to apomorphine HCI inducing penile erection and it also suggested that Gamigyuibitang has favorable effect to treatment of erectic dysfunctions induced by p,p-DDE.