• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.1
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• pp.10-18
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• 2014

This study carried out to evaluate the hydration heat analysis and fundamental characteristics such as air content, slump, compressive strength and dry shrinkage according to concrete with premixed cement, ternary concrete and OPC concrete for using concrete with premixed cement. The results of experiment are founded that concrete with premixed cement have sufficient performances such as workability, compressive strength and dry shrinkage. Also, the results of hydration heat analysis are founded that concrete with premixed cement have more performance than ternary concrete and OPC concrete at a point of view for the quality control such as thermal crack reducing and economic benefit. Therefore, it is desirable that concrete with premixed cement should be used to rise durability performance and convenience of maintenance.

• Current Photovoltaic Research
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• v.4 no.4
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• pp.159-163
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• 2016

Piled snow upon PV module interferes with Photoelectric Effect process through photovoltaic directly. As a result of this phenomenon, its generation efficiencies keep decreasing or are stuck at zero power generating status. In addition, PV facilities have been installed on those places such as water surface, roof-top, and other isolated places, dealing with conditions of "Securing high REC weighted value", "Difficulty of securing land" and so forth. Through this study, we are able to actualize the function of heating over PV modules when it snows. We adopted laminating method through heating film and modules, guaranteeing warranty more than for 25 years. Also we are trying remote control systemically, not by hardware control, to run parallel with automatic driving and monitoring system which enable to control operation time, insolation, amount of snowfall automatically. We applied analysis of actual proof to both snow removal PV system and general PV power system, and these led to bear power consumption analysis while snow-removing, and its comparison after finishing the task as "One stone, two birds." In the long run, we could carry out economic analysis against snow removal system, and this helps to verify the most maximized control method for snow removal conditons on a basis of weather information. this study shall let prevent people from negligent accidents, and improve power generation problems as mentioned from the top. Ultimately, we expect to apply this system to heavy snowfall regions in winter season in spite of its limited system installaion in Korean territory, initially.

• Pediatric Infection and Vaccine
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• v.27 no.1
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• pp.62-68
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• 2020

Acute bacterial sinusitis is one of the most common diseases in children, and 5-13% of patients with viral upper respiratory infection experience secondary bacterial sinusitis as a complication. Isolated sphenoid sinusitis is rarer than frontal, maxillary, and ethmoid sinusitis. However, it presents potentially devastating complications, such as cranial nerve involvement, brain abscess, and meningitis, owing to its anatomical location. Nontypeable Haemophilus influenzae (NTHi) commonly causes acute bacterial sinusitis but rarely causes bacteremia, particularly in immunocompetent patients. We present a rare case of a 14-year-old boy with bacteremia due to isolated sphenoid sinusitis caused by NTHi.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.5
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• pp.81-88
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• 2015

바이오매스는 유망한 신재생 에너지이다. 바이오매스는 액체 및 기체 연료로 전 환 할 수 있고, 다양한 공정을 통해 열 및 전력을 생산시키는데 사용된다. 바이오매스 가스화 공정은 바이오매스를 일산화탄소, 이산화탄소, 수소 및 메탄으로 이루어진 합성 가스로 전환시키는 기술이다. 바이오매스를 이용한 합성 가스 생산 및 활용은 세계적으로 늘어나는 에너지 필요성을 충족시킬 수 있는 대체에너지이다. 현재, 바이오매스 가스화의 주요 원료는 목질계 우드 칩을 주로 사용하고 있지만, 일반적으로 우드칩의 경우 수분을 다량 함유하고 있기 때문에 가스화 공정을 위해서는 별도의 건조처리를 필요로 한다. 우드칩의 건조에는 많은 에너지가 소요되고, 다량의 우드칩 건조에는 시간과 기상 및 공간적인 환경에 영향을 받는다. 본 연구에서는 미건조 우드칩의 가스화 공정을 위하여 미건조 우드칩에 숯을 각각 10, 30, 50 % 비율로 혼합하여 실험을 수행하였고, 실험결과 생산된 합성가스의 CO 농도 는 숯의 비율에 따라 14.9 ~ 25.6 % 증가되는 경향을 나타내었지만, 반대로 $CO_2$ 및 $CH_4$ 농도는 감소하였다. 이에 따라 합성가스 생산을 위한 미건조 우드칩과 숯의 최적혼합비율은 약 30 %로 판단되며, 발열량은 $1285.7kcal/Nm^3$, Gas yield는 $2.3Nm^3/kg$ 로 나타났다. 이에 적절한 숯의 혼합사용은 미건조 우드칩의 직접적인 가스화에 도움이 될 것으로 사료되며, 바이오매스 건조 공정에 필요한 에너지를 절약할 수 있을 것으로 판단된다.

• Fire Science and Engineering
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• v.14 no.1
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• pp.8-12
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• 2000

We had investigated thermal and ignition behaviors of textiles. Decomposition of textiles with temperature was investigated using a DSC and the weight loss according to temperature using a TGA in order to find the thermal hazard of textiles, and the ignition behaviors of textiles according to species and permeation amount of oil. In addition, ignition behaviors of those permeated into oils indicating different iodine value and of those with arid without air in reaction vessel of measuring equipment were studied with constant temperature method among ignition temperature measuring methods. As results, the range of decomposition temperature of synthetic fiber was slightly broad compared with that of natural fiber, pure cotton. Besides, the initiation temperature of heat generation of both samples riced in the case of no air injection in the reaction vessel. On the other hand, in the case of air injection that was lowered according to the increase in permeative amount of oils and fats and decreased quickly as sample was permeated into drying oil.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.463-469
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• 1988

The effects of moisture content and particle size of rice flour on the physical properties of the extrudate were examined by using a autogeneous single screw extruder. The moisture contents tested were in the range of 17-28% and the particle sizes were 18-60mesh and 60-120mesh. Samples were taken at different temperatures from the start-up period to the steady state operation. The expansion ratio increased and bulk density decreased as the moisture content and particle size of the flour decreased. The cutting force decreased and the air cell size became uniform as the moisture content and particle size of the flour decreased. As the moisture content increased, the yellowness of the extrudate powder decreased, while the lightness increased, the apparent viscosity increased and the water soluble index decreased. Gelatinization and partial dextrinization were apparent during the extrusion process, and the degree of dextrinization was appeared to be influenced by the levels of moisture content and particle size of rice flour.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.5
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• pp.340-344
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• 1991

On heating and fleering food-stuffs, it is very important to obtain informations about thermophysical properties of fishes for designing of freezing and heating equipment and analyzing of physico-chemical reaction during storage. It is particularly necessary to measure denaturation enthalpy, temperature, latent heat of freezing, activation energy, enthalpy, entropy and free energy on freezing and heating rate. In this study, DSC was used to study effects of freezing and heating rate on thermophysical properties and denaturation temperature on scanning rate $2.5-10.0^{\circ}C/min$. On increasing scanning rate, denaturation temperature of protein and lipid incresed and freezing point, activation energy, enthalpy, entropy were decreased. In freezing process free energy of fishes were found to be $14.2-18.9 kcal/mol$.

• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.113-121
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• 2020

In batch experiments, the adsorption of 7-epi-10-deacetylpaclitaxel was studied using Sylopute. Experimental equilibrium data were applied to Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. Among the four isotherm models tested, the Langmuir isotherm model gave the highest accuracy. The adsorption capacity was found to decrease with increases in temperature and the adsorption of 7-epi-10-deacetylpaclitaxel onto Sylopute was a favorable physical process. Adsorption kinetic data agreed very well with the pseudo-second-order kinetic model, while boundary layer diffusion and intraparticle diffusion did not play a key role in the adsorption process. The process of 7-epi-10-deacetylpaclitaxel adsorption onto Sylopute was exothermic and nonspontaneous. Also, the adsorption isosteric heat was independent of surface loading indicating an energetically homogeneous adsorbent.

• Solar Energy
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• v.11 no.2
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• pp.63-69
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• 1991

A Steady laminar natural convection heat transfer from two isothermal square beams attached to a vertical adiabatic plate has been studied numerically. The results have been obtained for dimensionless beam spacings, $0.5{\le}D/L{\le}3.0$, and for Gr=5000-10000 at ${\phi}_2/{\phi}_1=1.0$. 1. The local Nusselt number from the beam surface is increased with the dimension-less beam spacing D/L. but that of the downward surface of the lower beam is almost same as the D/L increases. And, the local Nusselt number from the upward surface of a lower beam is greatly increased with D/L. 2. The beam spacings of the maximum mean Nusselt number for the downward surface of an upper beam and the upward surface of a lower beam occur at. D/L =2.6 and 2.0 respectively. 3. The beam spacing for the maximum total mean Nusselt number occurs at D/L = 2.6.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.259-266
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• 2020

Magnetic gears have the same characteristics as mechanical gears, and each rotor does not come in contact, which is advantageous over mechanical gears in friction noise, heat generation, and maintenance. In addition, when the rotor using the coil-winding is applied, it is possible to control the output of the gear as well as to cut off its own drive in the emergency situation and to change its gear ratio. So the application of the magnetic gear is infinite. However, when the coil-winding rotor is used, cogging torque due to the attraction force between the permanent magnet and the iron core appears, which leads to an increase in the torque ripple component causing the rotor vibration. Therefore, in this paper, various shapes of the coil-winding rotor are analyzed to reduce the torque ripple of the rotor, and the optimum shape for reducing the torque ripple of the magnetic gear is presented.