• Resources Recycling
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• v.16 no.5
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• pp.57-64
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• 2007

Triboelectrostatic separation of mixed three kinds of plastics, PVC, PET and PMMA, in the range of similar gravity has been performed through a two-stage separation process. Polypropylene (PP) and high-impact polystyrene (HIPS) were found to be the most effective materials for a tribo-charger in the separation of PVC, PET and PMMA. In the 1st stage using the PP cyclone charger, PVC grade and recovery depended considerably on the air velocity (10 m/s), the relative humidity (<30%), the electric field (>200 kV/m) and the splitter position (+2 cm from the center) in the triboelelctrostatic separator unit. At an optimum condition a PVC grade of 99.6% and a recovery of 97.5% was achieved. In the 2nd stage using the HIPS cyclone charger, a PMMA grade of 98.3% and a recovery of 97.0% was obtained under the conditions of 10m/s air velocity, over 250 kV/m electric field, central splitter position and less than 40% relative humidity.

• Transactions on Electrical and Electronic Materials
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• v.10 no.6
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• pp.203-207
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• 2009

We have investigated the effect of ambient gases on the structural, electrical, and optical characteristics of ITO thin films intended for use as anode contacts in OLED (organic light emitting diodes) devices. These ITO thin films are deposited by radio frequency (RF) magnetron sputtering under different ambient gases (Ar, Ar+$O_2$, and Ar+$H_2$) at $300{^{\circ}C}$. In order to investigate the influences of the oxygen and hydrogen, the flow rate of oxygen and hydrogen in argon mixing gas has been changed from 0.5 sccm to 5 sccm and from 0.01 sccm to 0.25 sccm, respectively. The intensity of the (400) peak in the ITO thin films increased with increasing $O_2$, flow rate whilst the (400) peak was nearly invisible in an atmosphere of Ar+$H_2$. The electrical resistivity of the ITO thin films increased with increasing $O_2$ flow rate, whereas the electrical resistivity decreased sharply under an Ar+$H_2$ atmosphere and was nearly similar regardless of the $H_2$ flow rate. The change of electrical resistivity with changes in the ambient gas composition was mainly interpreted in terms of the charge carrier mobility rather than the charge carrier concentration. All the films showed an average transmittance of over 80% in the visible range. The OLED device was fabricated with different ITO substrates made with the configuration of ITO/$\alpha$-NPD/DPVB/$Alq_3$/LiF/Al in order to elucidate the performance of the ITO substrate. Current density and luminance of OLED devices with ITO thin films deposited in Ar+$H_2$ ambient gas is the highest among all the ITO thin films.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.4
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• pp.309-315
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• 2016

Recently, finite element analysis technique has been widely used for structural and mechanical understandings of human body in the dentistry field. This research proposed an effective finite element modeling method based on CT images, and parametric studies were performed for the occlusal simulation. The analyses were performed considering linear material behaviors and nonlinear geometrical effect, and validated with the experimental results. In addition, the skull models with two different molar relations such as Class I and full-CUSP Class II were generated and the analyses were performed using the proposed analytical method. As results, the relationships between the mandibular movement and occlusal force of both two models showed similar tendency in human occlusal force. However, stress was evenly distributed from teeth to facial bone in the skull model with Class I, while stress concentration was appeared in the model with full-CUSP Class II due to the changes of occlusal surfaces of the model.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.463-470
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• 2013

The objective of this study is to compare hospital performance between Local Government Hospitals and General Hospitals. To compare the result of the financial performance between two groups, there were significant differences in current ratio, Fixed ratio, total assets turnover, personnel expenses to gross revenues, management expenses to gross revenues, return on assets, operating margin. The significant impact relations of ROA(Return on Assets) were formed the total assets turnover, salaries, material costs, administrative expenses. Although two groups are the similar beds, most of LGH are in the red so the managers and local government must consider the financial efficiency of LGH.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.6
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• pp.502-516
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• 2002

Imwonshibyukji is a copying manuscript written around 1825, the 27th year of king Soonjo of the Chosun Period. It is a massive home encyclopedia of total 52 books and 100 volumes. It was quoted from many Chinese literatures The unpublished 'Jeongjoji'of its 17-20th volumes was analyzed to study the cooking methods on the Korean rice cakes (dduck) and studied for the degree of their usefulness and medical values in the light of the cooking and processing science. The book introduced 6 kinds of Korean rice cake: sirudduck (steamed rice cake), chinundduck (steamed and struck rice cake), zizinundduck (small oil fried rice cake), danggui (steamed rice cake mixed with rice power and honey), hondon (=danja: boiled and stuffed rice cake) and butu (fermented rice cake), all of which were composed of total 64 items. The main materials fur the Korean rice cake were as follows: sirudduck and butu were nonwaxy rice powder, chinundduct dinggui and hondon were glutinous rice powder, and zizinundduck was wheat flour. The side material was mainly natural food with the effect of a medicine. The literatures quoted in Imwonshibyukji are as follows: 4 Korean books including Ongheejabji were quoted total 28 times (41.5%), 5 Chinese books including Junsengpaljeon were quoted total 35times (52.2%), and I Japanese book Whawhansamjedohoi was quoted total 4 times (6.0%). The Korean rice cakes quoted in the Korean literature so far exist but the Chinese ones no longer exist. In the comparative analysis of Imwonshibyukji and other contemporary literatures, Chosunmoossangsinsikyorijebub was the most similar one to the book among others.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.6
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• pp.15-20
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• 2017

In this study, the fracture energy and displacement fields characteristics of particulate reinforced composite is evaluated. Wedge splitting test was performed at various temperatures. Fracture energy of material is calculated at room temperature, $-40^{\circ}C$ and $-60^{\circ}C$. Displacement and strain fields of specimen surface were visualized by using digital image correlation. The surface displacement fields of the specimens were analyzed by mark tracking method using digital image correlation. The results showed that, the fracture energy was decreased as temperature decreased. The surface displacement fields at room temperature were similar to there at $-40^{\circ}C$. The surface displacement fields at $-60^{\circ}C$ was significantly reduced because of the brittle behavior. The strain fields of the specimen surface decreased as temperature decreased form room temperature to $-60^{\circ}C$.

• Coupled systems mechanics
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• v.9 no.2
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• pp.163-182
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• 2020

Coupled thermo-mechanical analysis of reinforced concrete slab at elevated temperatures from a fire accounting for nonlinear thermal parameters is carried out. The main focus of the paper is put on a one-way continuous reinforced concrete slab exposed to fire from the single (bottom) side as the most typical working condition under fire loading. Although contemporary techniques alongside the fire protection measures are in constant development, in most cases it is not possible to avoid the material deterioration particularly nearby the exposed surface from a fire. Thereby the structural fire resistance of reinforced concrete slabs is mostly influenced by a relative distance between reinforcement and the exposed surface. A parametric study with variable concrete cover ranging from 15 mm to 35 mm is performed. As the first part of a one-way coupled thermo-mechanical analysis, transient nonlinear heat transfer analysis is performed by applying the net heat flux on the exposed surface. The solution of proposed heat analysis is obtained at certain time steps of interest by α-method using the explicit Euler time-integration scheme. Spatial discretization is done by the finite element method using a 1D 2-noded truss element with the temperature nodal values as unknowns. The obtained results in terms of temperature field inside the element are compared with available numerical and experimental results. A high level of agreement can be observed, implying the proposed model capable of describing the temperature field during a fire. Accompanying thermal analysis, mechanical analysis is performed in two ways. Firstly, using the guidelines given in Eurocode 2 - Part 1-2 resulting in the fire resistance rating for the aforementioned concrete cover values. The second way is a fully numerical coupled analysis carried out in general-purpose finite element software DIANA FEA. Both approaches indicate structural fire behavior similar to those observed in large-scale fire tests.

• Journal of Yeungnam Medical Science
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• v.2 no.1
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• pp.23-30
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• 1985

Keloids are abnormally healed skin wounds that develop in the subpapillary layer of the dermis. They are a lesion with wide, raised and deep scars. They exceed the original dimensions of the wound and grow mounds upon mounds of collagen in a pseudotumor fashion. Their treatment may take several forms such as surgery, intralesional injection of steroid, compression, superficial irradiation, and combination therapy. However, absolute method is nothing until now. Recently, the cryosurgery shows relatively good effect in treatment, so we tried the clinical experience with cryosurgery in the treatment of keloids. Material and methods: During the past 2 years, we treated 20 individuals of the keloids with severe itching and pain. The age ranged from 5 to 45 years old. Only 6 cases were biopsied before and after cryotherapy. The cryosurgery set we used was Toitu model CR 201 $N_2O$ gas (tip temperature is $-80^{\circ}C$) and was applied directly on the lesion about 4 to 5 minutes with slight compression. After cryosurgery in keloids, the following results were obtained: 1. It is both quick and easy method. 2. It causes little or no pain and no loss of blood. 3. Integumentary normalization is rapid. The new scar tissue is smaller, and more elastic and soft. 4. The pain, itching and paresthesia commonly associated with keloid is usually disappeared. 5. Other treatment can be used after cryosurgery. 6. Histologic picture after cryosurgery is similar with the result of steroid injection. 7. The mechanism of the cryosurgery in keloids is the result of the direct tissue destroying action and cryoimmunologic reaction.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.6
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• pp.7-14
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• 2017

This study manufactured a minimum quantity lubrication (MQL) supply system and identified the optimal MQL machining cutting conditions for plastic mold steel (SCM440). A series of experiments were consisted of twice. Optimal cutting conditions were derived using the Taguchi method, and cutting force variance; surface roughness; tool wear; and cutting temperature in dry, wet, and MQL machining were measured experimentally for these optimal conditions. The measured results decreased from dry to wet and MQL machining, being particularly large for dry machining due to increased cutting time. Measured MQL machining metrics were similar to those for wet machining, particularly for surface roughness, which is an index of machining quality.

• Journal of Convergence for Information Technology
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• v.10 no.1
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• pp.243-250
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• 2020

Due to the unique sourness and sweet taste of Aronia, it is necessary to develop it for processing rather than raw. The antioxidant activity and cytotoxin about the aronia powder fermentation extract using lactobacillus are verified. In the case of total polyphenol content, the content of non-fermented extract was 32.15 ㎍/mg fermentation extract, 43.08 ㎍/mg after fermentation, and the flavonoid content was 0.47 ㎍/mg in non-fermented extract and 0.44 ㎍/mg in fermented extract, which was similar to that of non-fermented extract. In the DPPH radical inhibition assay, 77.5% of the non-fermented extract and 89.1% of the fermented extract showed better activity than the non-fermented extract. Nitric oxide (NO) measurement showed a concentration-dependent inhibitory effect. From the above results, it was confirmed that the fermentation of Aronia powder could be utilized based on some antioxidant activities and the possibility of using it as a vegetable extract and fermented cosmetic material in the future.