• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.10
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• pp.791-797
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• 2012

Mineral insulating oils are an important insulating materials in oil-filled transformer. However, the mineral oil is the cause of the environmental problem. The vegetable oils are substitutes for mineral oil because of its biodegradability characteristic. As large size and high rating of the transformer increases, the losses increase at a faster rate. So insulating oil is forced circulation in the oil-filled transformer by using oil pumps. The flow electrification occurs when insulating oil was forced to be circulated. To check the flow electrification, had conducted experiments varying factors. As a result, the streaming electrification could see the changes according to flow velocity, oil temperature and insulation materials.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.209-211
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• 1996

The dielectric breakdown characteristics of DGEBA/MDA/SN system filled with $Al_2O_3$ under AC high electric field were investigated. As the filler content increased, the dielectric breakdown strength increased, but decreased at higher filler content than 5 phr. The probability of defects such as air bubbles, peel between filler and epoxy resin insulator, etc. increase proportionally to filler contents. Fillers blockade the treeing growth and relax the electric field at the tip of electrical tree and the treeing propagation rate decreases so that the strength showed higher strength at lower filler content than 5 phr.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.129-133
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• 2019

In this paper, we developed a system to monitor the storage capacity of suction-type device such as vacuum cleaner or crop harvesters. The monitoring system consists of load cells and a differential pressure sensor which simultaneously monitor the weight and volume of the stock. Since weighing objects stored in storage containers alone cannot fully monitor the level of filling, more accurate monitoring can be achieved by monitoring volume and fusion with weight information. The volume was monitored using a phenomenon in which the flow rate of the inhaled air varies depending on the volume of the object filled in the storage container. In this paper, we developed a system to monitor the storage in three stages: low, medium and high.

• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.23-244
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• 2022

The Pulpose of this systematic review is aimed to establish the procedure of the injection with saftey and efficiency in the pre-hospital cardiac arrest patient performing the cardiopulmonary resuscitation (CPR), compared with traditional medication administration using Ampoule and medication administration with Prefilled Syringe. Databases were searched for CPR, heart arrest, resuscitation, Pre-filled Syringe, and Ampoule by the electronic data research including Pubmed, EMBASE and Cochran Library of Konyang University Library: 4 articles were selected by three co-authors using EndNote X20 and Covidence (Covidence.org) and were systematically reviewed. The Result of this study, the medication administration using Pre-fillled Syringe improves the safety of patients and Emergency medical workers by reducing the error in administration dose and administering the drug in safe than the medication adminisrtaion using Ampoule, also, contributes to the increment of survival rate of cardiac arrest and severe patients by decreasing the administration time that prevents the delay of medication administration.

• The Journal of the Korean dental association
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• v.14 no.8
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• pp.655-658
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• 1976

The auther had studied dental caries and periodontal disease and other important oral disease in the 806nout patient who came to dental Department in N.M.C. during 1974. The obtained results were as follows ; 1) The dental caries experience rate in the out patient of Dental Departanent in N.M.C. was 8202% and the D.M.F. teeth index was 3.3. 2) The decayed teeth index was 2.18 and the missed teeth index was 0.69 and the filled teeth index was 1065. 3) The periodontal disease rate was 82.8% 4) The oral cancer rate was 2%, mandible and maxillary fracture rate was 4%, and trigeminal neuralgia rate was 0.6%.

• Journal of the korean academy of Pediatric Dentistry
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• v.21 no.2
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• pp.463-468
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• 1994

The purpose of this study was evaluation of the oral health of cerebral palsied children by considering the DMFT index. The 31 cerebral palsied children(Male 20, Female 11) participated in the study, and mean age was 11.3 years. All patient were examined for determination of decayed tooth, missing tooth, filled tooth. For children with only deciduous dentition, the dmf system was used; for children with only permanent dentition, the DMF system was used; for children with mixed dentition, a combination of two systems(dmf and DMF) was used. The results were as follows: 1. In the deciduous dentition, dmft index was 11.60.(dt rate ; 83.62%, mt rate ; 12.07%, ft rate ; 4.31 %) 2. In the mixed dentition, DMFT index was 12.25 and dmft index was 10.75.(DT rate ; 90.00 %, MT rate ; 0 %, FT rate ; 10.00 %, dt rate ; 60.53 %, mt rate ; 28.95 %, ft rate ; 10.52 % ) 3. In the permanent dentition, DMFT index was 8.16.(DT rate ; 87.77 %, MT rate ; 11.51 %, FT rate ; 0.72 %)

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.4
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• pp.379-388
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• 2006

Two mesophilic trickling bed bioreactors filled with two different types of media, hydrophilic- and hydrophobic-cubes, were designed and conducted for hydrogen production under the anaerobic fermentation of sucrose. Each bioreactor consisted of the column packed with polymeric cubes and inoculated with heat-treated sludge obtained from anaerobic digestion tank. A defined medium containing sucrose was fed by the different hydraulic retention time(HRT), and recycle rate. Hydrogen concentrations in gas-phase were constant, averaging 40% of biogas throughout the operation. Hydrogen production rate was increased till $10.5\;L{\cdot}h^{-1}{\cdot}L^{-1}$ of bioreactor when influent sucrose concentrations and recycle rates were varied. At the same time, the hydrogen production rate with hydrophobic media application was higher than its hydrophilic media application. No methane was detected when the reactor was under a normal operation. The major fermentation by-products in the liquid effluent of the both trickling biofilters were acetate, butyrate and lactate. In order to run in the long term operation of both reactor filled with hydrophilic and hydrophobic media, biofilm accumulation on hydrophilic media and biogas produced should be controlled through some process such as periodical backwashing or gas-purging. Four sample were collected from each reactor on the opposite hydrogen production rate, and their bacterial communities were compared by terminal restriction fragment length polymorphism (T-RFLP) analysis of PCR products generated using bacterial 16s rRNA gene primers (8f and 926r). It was expressed a marked difference in bacterial communities of both reactors. The trickling bed bioreactor with hydrophobic media demonstrates the feasibility of the process to produce hydrogen gas. A likely application of this reactor technology can be hydrogen gas recovery from pre-treatment of high carbohydrate-containing wastewaters.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.3
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• pp.71-82
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• 2012

Common bulking agents in composting system include woody materials such as sawdust and woodchips. These bulking agents are mainly used for the purpose of the proper control of C/N ratio and moisture content in the composting. The topic for the effect on air permeability of bulking agents has far received relatively little attention in the composting field. This study investigated the effect of bulk density, moisture content, air-filled porosity, particle size and air flow rate on air permeability of several mixture ratios of sawdust and woodchip bulking agent. Increasing the moisture contents, the air-filled porosity was decreased and the particle size was increased for all kinds of bulking agent mixtures. Especially, with the increasing of mixing ratio of woodchip, these effects were sharply magnified. The air permeability respond to air-filled porosity was very similar to that for moisture content which was anticipated the linear relationship between air-filled porosity and moisture content. Above the region of moisture content 0.25 or 0.43(d.b.)(20 or 30% w.b.), the pressure drop decreased even though air-filled pore spaces were filling with water. Especially, to the particle size of 5 mm the pressure drop was decreased exponentially, so the air permeability was dramatically improved. By the water had the role of binding of the small particles, the macropores less resistances to air flow were created in the matrix. The effect of particle size on air permeability was much stronger than that of air-filled porosity or moisture content. And it is needed the preparing of initial particle size above 5 mm for efficient composting.

• Journal of ILASS-Korea
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• v.12 no.2
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• pp.108-114
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• 2007

This study investigates the influence of energizing duration on the fuel atomization characteristics of biodiesel injected through a high pressure common-rail injector. In order to analyze the effect of energizing duration on the fuel injection rate performance, the injection rate of biodiesel fuel is obtained from the pressure variation in the tube filled with fuel in injection measuring system. On the other hand, the atomization characteristics of biodiesel was measured and compared in terms of Sauter mean diameter(SMD), arithmetic mean diameter(AMD), droplet mean velocity, and detected droplets number by applying a phase Doppler particle analyzer(PDPA). It was revealed that the injection mass and maximum injection rate increase with increase of the energizing duration. Moreover, the increase of energizing duration improves the atomization performance of biodiesel fuel because it induces higher droplets momentum and velocity.

• Journal of Environmental Science International
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• v.7 no.5
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• pp.679-685
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• 1998

The Soysauce wastewater removal characteristics of submerged biofilters filled with two filter media respectively were experimentally examined with constant temperature, pH value and variable BOD loading and recirculation ratio. The decreasing order of BOD removal is Netring(random plastic media), cubic wire meshes(plastic module). This is mainly due to the media characteristics such as void ratio, specific surface area and media shapes. The BOD removal ratio decreases with increasing $BOD_5$/ volumetric loading rate, and the loading rate for the BOD removal over 85% is lower than 1.5kg$BOD_5$ 5/$m^3$d for the plastic media of Netring and cubic wire meshes. The $BOD_5$ removal rate increases with the recirculation ratio, but the rate of increase become smaller as the recirculation ratio increases over 20. When $BOD_5$ volumetric loading is 1.5kg$BOD_5$/$m^3$d, the required recirculation ratio to obtain 85% BOD$_{5}$ removal is about 20 for Netring and it was about 30 for cubic wire meshes.s.