• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.31-41
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• 2016

Damage to structures, such as bridge piers, are increasing rapidly due to the debris moving along rivers at the time of flooding. Therefore, the debris fin, debris deflector and debris sweeper, which are debris reduction systems, were produced in this study and an accumulation experiment was carried out on the experimental channel according to the existence of the reduction system. The debris fin is the reduction system that creates parallel flow on debris accumulated on the bridge to pass through the bridge, which was produced using wood. In addition, the debris deflector was produced using steel pipes and it has the type of detouring the direction of debris. The debris sweeper passes the debris using the magnetic force rotation of a screw-shaped cylindrical structure by water flow and it was produced using acrylic material. The experiment was carried out by analyzing the level of accumulation according to the hardness and dropping method of the debris and comparing the accumulation rate of reduction systems, and the experiment was carried out 5 times. According to the experimental results, there was a difference in the accumulation rate according to the type of reduction system and the shape of debris, and it often depended significantly on the initial shape of debris accumulation. The direct debris reduction effect on the bridge was higher in the order of the debris deflector, debris sweeper and debris fin, but in case of the debris deflector, damage, such as stream turbulence, changes in water level and river bed, and the loss of deflector can occur due to debris accumulated directly on the debris deflector. Therefore, it is necessary to design the debris deflector considering these issues.

• Journal of Conservation Science
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• v.26 no.1
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• pp.1-12
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• 2010

The crucibles of Baekje Kingdom from the Ssangbukri Site which were used for glass and metal melting had light brown, grayish blue and grayish brown colored bodies. In thin section, the crucibles contained numerous quartz grains and pottery fragments. The surface was covered with fine grained quartz for thermal resistance. Based on decomposition of mica group minerals and formation of mullite detected by X-ray diffraction analysis, it was inferred that all crucibles have been fired over $1,000^{\circ}C$. It was also found that firing temperature has exceeded $1,100^{\circ}C$ in some crucibles because feldspar was not detected. The maximum temperature was assumed at $1,200^{\circ}C$. The magnetic susceptibility values and geochemical characteristics sorted out the crucibles into two groups that differed from the characteristics of the local soils. This reflected geological setting of the site where the alluvium was formed from two kinds of surrounding rock masses, granite gneiss and biotite granite. However, the local soils had similarities with the crucibles in weathering degree and geochemical behavior of major elements. In consequence, it was considered that the raw clay of the crucibles was supplied from the local area of the site.

• Journal of Microbiology and Biotechnology
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• v.23 no.5
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• pp.644-651
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• 2013

The fermented manure derivative known as Preparation 500 is traditionally used as a field spray in biodynamic agriculture for maintaining and increasing soil fertility. This work aimed at characterizing the product from a microbiological standpoint and at assaying its bioactive properties. The approach involved molecular taxonomical characterization of the culturable microbial community; ARISA fingerprints of the total bacteria and fungal communities; chemical elemental macronutrient analysis via a combustion analyzer; activity assays for six key enzymes; bioassays for bacterial quorum sensing and chitolipooligosaccharide production; and plant hormone-like activity. The material was found to harbor a bacterial community of $2.38{\times}10^8$ CFU/g dw dominated by Gram-positives with minor instances of Actinobacteria and Gammaproteobacteria. ARISA showed a coherence of bacterial assemblages in different preparation lots of the same year in spite of geographic origin. Enzymatic activities showed elevated values of ${\beta}$-glucosidase, alkaline phosphatase, chitinase, and esterase. The preparation had no quorum sensing-detectable signal, and no rhizobial nod gene-inducing properties, but displayed a strong auxin-like effect on plants. Enzymatic analyses indicated a bioactive potential in the fertility and nutrient cycling contexts. The IAA activity and microbial degradation products qualify for a possible activity as soil biostimulants. Quantitative details and possible modes of action are discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.138-144
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• 2017

With the increase in power consumption due to the surge in the demand for power, it is necessary to improve the quality or design of the power (supply) for the purpose of reducing the energy consumption and so reduce the power loss. The switchboard is a mechanical device that receives electricity from the electricity generation facilities of KEPCO and divides it into the facilities required for each building. Switchboards generally consist of enclosures, switches, power conductors, and control components. This study deals with energized power conductors, which constitute the main element in the switchboard. Through the measurement of the effective ac resistance, it was confirmed that the vertical array structure of the conventional type plate conductor is inefficient. If the effective AC resistance increases significantly, the sectional area of the conductor becomes relatively large due to the skin effect. In this study, we studied the energy and material savings that could be obtained using the asterisk (*) array structure, which minimizes the effective ac resistance by reducing the skin effect. The core technology principle of this study is the energy saving switchgear based on conductor resistance reduction technology utilizing the asterisk array structure. The present invention involves a plate-shaped conductor arrangement structure capable of canceling out the magnetic field generated on each of the plate conductors (rst or abc) of the AC power supply in the power distribution panel by mutual action. The effect of this structure is to reduce the amount of inductive reactance due to the increase in the cross-sectional area and reduction of the effective AC resistance.

• Journal of Korean Neurosurgical Society
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• v.29 no.10
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• pp.1316-1321
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• 2000

Objectives : The authors analyzed the surgical series of Cushing's disease to evaluate the proper treatment policy and to verify the possible prognostic factors. Material and Methods : Of 50 patients diagnosed as Cushing's disease and operated at Department of Neurosurgery of our institute between 1988 and 1999, 48 patients with available medical records were analyzed retrospectively. Mean follow-up period was 48 months(3 to 109 months). Preoperative diagnosis was made after evaluating the patients with multiple-stage endocrinological studies and 31 selective patients were evaluated with inferior petrosal sinus sampling(IPSS). Magnetic resonance imaging(MRI) and/or high resolution computerized tomography(CT) was done in all patients. A total of 51 transsphenoidal adenomectomy(TSA) were performed including 3 revision for initial surgical failure cases. Remission was decided on the basis of both endocrinological criteria and clinical status. Radiation and/or ketoconazole therapy were applied to failed cases. For the verification of prognostic factors, the authors evaluated the statistical significance of multiple variables over remission rate by chi-square test. Result : Sensitivity of IPSS for central localization was 93.5% which was better than that of MRI(87.5%). But for lateralization, it was 72.4% for IPSS versus MRI 90.5%. Success rate of TSA was 82%(42/51) and recurrence rate was 9%(4/48). When including adjuvant treatments for surgically failed cases, overall success rate was 89.6% and all of 3 reoperated cases(TSA) due to recurrence were successful. Significant complication occurred in 7.8%(4/51) after TSA including hypopituitarism, diabetes insipidus, and visual loss. Non-existence of tumor in MRI and prolonged symptom duration(>3 years) were significant prognostic factors. Conclusion : TSA can be considered as initial treatment for Cushing's disease. In surgically failed cases, multiple treatment modality may improve the overall outcome and repeated TSA for recurrent cases seem to provide similar success.

• Journal of Conservation Science
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• v.30 no.4
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• pp.335-343
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• 2014

This study classified the result of non-metallic inclusion analysis and result of microstructure investigation on the ironware excavated in the Baekje region into Han River, Geum River, and Yeongsan River to estimate the iron making temperature and study the characteristics of regional and temporal characteristics of the heat treatment technology and steel making technology. Regardless of era, bloom iron and sponge iron are judged to be the major method for making as a directreduction process in all three regions. The result of the reinterpretation of the non-metallic inclusion by the oxide ternary constitutional diagram suggest that the temperature inside of the furnace is estimated to be between $1,100{\sim}1,300^{\circ}C$ while making the steel. The magnetic iron ores are the major raw material of steel ore and irons with high $TiO_2$ are estimated to use iron sands. Ironware with $CaO/SiO_2$ rate higher than 0.4% are considered to have artificially added the flux of calcareous materials. It was found that the iron making method is the solid caburizing-steel which caburizes low-carbon steels by the CO gas and $CO_2$ gas created when heating the forging furnace with charcoal. Also, the ironware manufacturers in the Baekje during 3rd century recognized the heat treatment technology as they performed carburizing process and quenching to intentionally increase the strength of necessary parts.

• Journal of Conservation Science
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• v.34 no.3
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• pp.179-193
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• 2018

This study is aimed to investigate the provenance of raw materials and firing temperature of jar coffins excavated from the Oryang-dong kiln site and Jeonchon tomb site, Naju, Korea. Most of jar coffin samples shows same range of magnetic susceptibility and have gray color, while 404 and 405 of Jeongchon site are reddish yellow. In some samples fired at high temperature, the water absorption at the mouth rim and body part of same jar coffin were 3.50% and 7.56% respectively. It means that heat transfer and equilibrium in the kiln was not properly continued and the heat energy transferred to the mouth rim and the body part was different. In the petrographic analysis, As a tempering materials, biotite, weathered quartz and feldspar were added in the jar coffins of Oryang-dong site, and biotite, polycrystalline quartz and feldspar in it of Jeongchon site. Tempering materials were found more in the body than in the mouth rim of same jar coffin of Oryang-dong site. It seemed that some samples were fired at over 1,000 to $1,100^{\circ}C$, which showed vitrified texture in the scanning electron images and the rest of samples were fired at below $900^{\circ}C$. Due to similarity of chemical compositions, it is estimated that jar coffins of Jeongchon tomb were produced and supplied from Oryang-dong kiln site. However, the slight difference of some trace elements distribution of samples is attributed to the selection of clay depending on the location.

• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.436-442
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• 2014

In this study, we developed an optical-fiber sensor using cobalt chloride solution to monitor temperature in real-time between long distance points unaffected by the electro-magnetic wave and the vibration. Cobalt chloride solutions were made using 10% water and 90% ethanol (v/v) solution. The transmittance of these solutions was analyzed on 655 nm using UV-Visible spectrometer regarding temperature change. Also 30.8 mM cobalt chloride solution was gelled by dissolving polyvinyl butyral and the transmittance of this was analyzed on 655 nm regarding temperature change. The results of transmittance and optical power measurement showed decrease of both transmittance and optical power with increase of temperature from 66.8% and 149.5 nW at $25^{\circ}C$ to 7.1% and 48 nW at $70^{\circ}C$, respectively. These results support the possibility of gelled cobalt chloride/polyvinyl butyral as an optical-fiber sensor to monitor temperature change.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.1
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• pp.41-49
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• 1991

The reaction of molten urea with paraformaldehyde in sealed tubes has been examined, and the concentrations of the products obtained from this reaction have been contrasted to previous results from the identical reaction carried out in open beakers. In these studies, high performance liquid chromatography(HPLC) and nuclear magnetic resonance(NMR) spectroscopy were used to analyze the products formed in the reactions. These products were biuret, triuret, dimethylenetriurea, methylenediurea, and biuretmethyleneurea. The results from the HPLC analyses showed that the concentrations of dimethylenetriurea and methylenediurea in the reaction products increased as the amount of the paraformaldehyde starting material increased. However, the amount of biuret formed in the products decreased as the paraformaldehyde concentration was increased in the urea melt. The results from the NMR analyses showed that the $NH_2$ resonance frequencies for urea, methylenediurea, and dimethylenetriurea all occurred at approximately 5.6 ppm, while the $NH_2$ frequencies for biuret and triuret occurred at approximately 6.9ppm. In the case of biuret and triuret, NH protons absorb between 8.5 and 9.5 ppm, whereas the NH protons in methylenediurea and dimethylenetriurea absorb in the 6.5-6.6ppm region. The melt reaction seems to hold promise as a different technique for ureaform preparation in general.

• The Journal of the Petrological Society of Korea
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• v.28 no.4
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• pp.227-236
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• 2019

Medium to coarse-grained biotite granodiorite was used to build the Standing Buddha Statue in the Gwanchoksa temple. An ancient document revealed the period and place of constructing the statue: it was made in the northwest of Mt. Banyasan and then moved eastward. Also, the comparison of standing Buddha statue and basement rock in terms of texture, magnetic susceptibility, and gamma spectrometer shows that they have similar characteristics, which is considered to be the same provenance rock. The damage caused by surface contaminants observed in the statue seems to be a combined effect of environmental factors and aging of the epoxy resin. After removal of the contaminants in 2007, the contamination has resumed, and continuous monitoring is necessary. Algal engraftment becomes faster when biological contamination occurs on the surface of stone cultural heritage. Since the secondary lichen growth forms a symbiosis with mold, it is necessary to observe the spatial and distributional changes. Also, the aging epoxy resin may cause secondary damage due to contaminants generated due to the determination of salts, and deterioration of bonding strength due to breaking out. Thus it is desirable to secure stability through proper conservation management.