• Journal of Korean Society of Environmental Engineers
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• v.28 no.11
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• pp.1154-1161
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• 2006

Air drying equipment was built as a device for reduction of dewatered cake from wastewater and waterworks sludge and to reproduce it by reusable matter. Dewatered cake was supplied into the air drying equipment which operated by air velocity of 80 m/sec, air rate 30 $m^3/min$ and air temperature of $40^{\circ}C$, and dried to produce the dried powder. The air drying equipment was composed of the air ejector which made high-speed fluid field, and cyclone which made circling fluid field. Dewatered cake was crushed at the high-speed zone as first step, and formed into dried powder of sphere shape by the collision between particles at the circling fluid zone.. Wastewater sludge with water content of 82.5 wt% was supplied 1.0 kg/min into air drying equipment and produced the dried powder which had the water content of 62.3 wt% and mass median diameter of 2.4 mm after process. At that time, it was analyzed that water removal rate was 0.1 $H_2O{\Delta}kg/min{\cdot}DS$ kg and air consumption was 170 $m^3/DS$ kg. Under same experimental conditions, when waterworks sludge was dried, water content of dried powder decrease to 47.5 wt% and mass median diameter decrease 2.1 mm and water removal rate increase 0.13 $H_2O{\Delta}kg/min{\cdot}DS$ kg. Air consumption increase 180 $m^3/DS$ kg with comparison to the results of wastewater sludge. Therefore, this technology was evaluated that drying the dewatered cake of waterworks sludge was more efficient than wastewater sludge, and also economical sludge handling technology due to drying the cake by only air.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.2
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• pp.174-188
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• 1999

The purpose of this study is to evaluate the precision and accuracy of a three dimensional cephalogram constructed by using the frontal and lateral cephalogram of twelve human dry skulls. After achieving the three dimensional image reconstruction program, we tried to apply this program to two dentofacial deformity patients. 1. Conventional nasion relator in cephalostat was used to reproduce the same head position for the same dry skull. The mean difference of the three dimensional cephalogram for the same dry skull was $0.34{\pm}0.33mm$. Closeness of repeated measures to each skull reveals the precision of this method for the three dimensional cephalogram. 2. Concerning the accuracy, the mean difference between the three dimensional reconstruction data and actual lineal measurements was $1.47{\pm}1.45mm$ and the mean magnification ratio was $100.24{\pm}4.68%$. This Diffrerence is attributed mainly to the ill defined cephalometric landmarks, not to the positional change of the dry skull. 3. Cephalometric measurement of lateral and frontal radiographs had no consecutive magnification ratio because of the different focus-object distance. The mean difference between the frontal and lateral cephalogram to the actual lineal measurements was $4.72{\pm}2.01mm$ and $-5.22{\pm}3.36mm$. Vertical measurements were slightly more accurate than horizontal measurements. 4. Applying to the actual patient analysis, it is recommendable to use this program for analyzing the asymmetry or spatial change after operation. The orthodontic bracket would be a favorable cephalometric landmark for constructing the three dimensional images.

• Composites Research
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• v.16 no.1
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• pp.1-12
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• 2003

This study developed SiC$_{p}$/A1$_2$O$_3$$_{f}$/Al composites for electronic packaging to which reinforcements were added with the volume fractions of 49%, 56% and 63% by the squeeze casting method. 0.8 wt. % of the inorganic binder as well as the A1$_2$O$_3$ fiber and SiC Particles with the volume fraction of 1:10 were added to the composites, which were produced in the newly designed mold. For the produced SiC/Al composites, the CTEs (coefficients of thermal expansion) were measured from 30 to 300 and compared with the FEM numerical simulation to analyze the temperature dependent properties. The experiment showed the CTEs of SiC$_{p}$/A1$_2$O$_3$$_{f}$/Al composites that were intermediate values of those of Rule of Mixture and Turner's Model. The CTEs were close to Turner's Model in the room temperature and approached the Rule of Mixture as the temperature increases. These properties analyzed from the difference of the average stress acting between the matrix and the reinforcements proposed in this study.

• Restorative Dentistry and Endodontics
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• v.34 no.6
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• pp.508-514
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• 2009

The purposes of this study were to compare the efficacy of irrigation systems by removing a calcium hydroxide $(Ca(OH)_2)$ paste from the apical third of the root canal and the effect of the patency file. Sixty single rooted human teeth were used in this study. The canals were instrumented by a crown-down manner with .04 taper ProFile to ISO #35. $Ca(OH)_2$ and distilled water were mixed and placed inside the root canals. The teeth were divided into 6 groups according to the root canal irrigation system and the use of patency file as follows: group 1 - conventional method: group 2 - $EndoActivator^{(R)}$: group 3 - $EndoVac^{(R)}$; group 4 - conventional method, patency: group 4 - $EndoActivator^{(R)}$, patency; group 6 - $EndoVac^{(R)}$, patency. All teeth were irrigated with sodium hypochlorite. After the root canal irrigation, the teeth were split in bucco-lingual aspect. Percentage of the root canal surface coverage with residual $Ca(OH)_2$ until 3 mm from working length was analyzed using Image Pro Plus ver. 4.0. Statistical analysis was performed using the One-way ANOVA, t-test and Scheffe's post-hoc test. Conventional groups had significantly more $Ca(OH)_2$ debris than $EndoActivator^{(R)}$, $EndoVac^{(R)}$ groups. There was no significant difference between $EndoActivator^{(R)}$ and $EndoVac^{(R)}$ groups. Groups with patency file showed more effective in removing $Ca(OH)_2$ paste than no patency groups. but. it was no significant difference. This study showed that $EndoActivator^{(R)}$ and $EndoVac^{(R)}$ systems were more effective in removing $Ca(OH)_2$ paste from the apical third of the root canal than conventional method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.279-279
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• 2007

비휘발성 메모리 Fe-RAM은 빠른 정보처리 속도와 전원공급이 차단되었을 때도 계속 정보를 유지할 수 있는 비휘발성 특징과 더불어 저전압, 저전력 구동의 장점이 있어서, 차세대 메모리로 많은 주목을 받고 있다. FeRAM에 사용되는 강유전체는 주로 Pb(Zr,Ti)$O_3$가 적용되었는데, 최근에는 비납계 강유전체의 연구도 활발히 이루어지고 있다. 이러한 비납계 강유전체 중에서 가장 특성이 우수한 물질은 $(Bi,La)_4Ti_3O_{12}$ (BLT) 이다. 그런데 BLT는 결정 방향에 따른 강한 이방성의 강유전 특성을 나타내기 때문에 BLT 박막을 이용하여 Fe-RAM 소자 등을 제작하기 위해서는 결정의 방향성을 세심하게 제어하는 것이 매우 중요하다. 지금까지 연구된 BLT 박막의 방향성 조절결과를 보면, BLT 박막을 스핀 코팅 법 (spin coating method)으로 증착하고, 핵생성 열처리 단계를 조절하여 무작위 방향성을 갖는 박막을 제조하는 방법이 일반적이었다. 그런데 이러한 스핀 코팅법에서의 핵생성 단계의 제어는 공정 조건 확보가 너무 어려운 단점이 있다. 이러한 어려움을 극복할 수 있는 대안은 스퍼터링 증착법(sputtering deposition method), PLD (pulsed laser deposition)법 등과 같은 PVD (physical vapor deposition) 법의 증착방법을 적용하는 것이다. PVD 법으로 증착하는 경우에는 이미 박막 내에 무수한 결정핵이 존재하기 때문에 핵생성 단계가 필요가 없게 된다. PVD 증착법의 적용을 위해서는 타겟의 제조 및 평가 실험이 선행되어야 한다. 그런데 벌크 BLT 재료의 소결공정 조건과 전기적 특성에 관한 연구 결과는 거의 발표가 되지 않고 있다. 본 실험에서는 $Bi_2O_3,\;TiO_2,\;La_2O_3,\;Nb_2O_5\;and\;Al_2O_3$ 분말들을 이용하여 최적의 조성을 구하기 위하여 $Nb^{+5}$ 와 $Al^{+3}$을 $Ti^{+4}$ 자리에 소량 치환시켜 제조하였다. 혼합된 분말을 하소 후 pellet 형태로 성형하여 소결을 실시하였다. 시편을 1mm 두께로 연마하고, 양면에 silver 전극을 인쇄하여 전기적 특성을 측정하였다. 측정결과 $Ti^{+4}$ 자리에 $Nb^{+5}$를 치환하여 제조한 시편에서 $2P_r{\sim}31\;{\mu}c/cm^2$정도의 매우 우수한 특성을 얻었다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.6
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• pp.751-758
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• 2017

The objective of this study was to determine the effects of moisture content and screw speed on the physical properties of extruded soy protein isolate (SPI). Expansion index, water absorption index, texture, integrity index, color, and nitrogen solubility index of extruded SPI were analyzed to determine the relationship with extrusion conditions. Extrusion conditions were moisture content (40, 50, and 60%) at a fixed die temperature ($140^{\circ}C$) and screw speed (250 rpm). The other extrusion conditions were screw speed (150, 250, and 330 rpm) at a fixed moisture content (55%) and die temperature ($140^{\circ}C$). Specific mechanical energy (SME) input decreased as moisture content increased from 40 to 60%. However, SME input increased as screw speed increased from 150 to 330 rpm. Expansion ratio and piece density decreased as moisture content and screw speed increased, and specific length increased as moisture content and screw speed increased. The extruded SPI at 40% moisture content had higher water absorption index, texture, and color differences than those of the extruded SPI at other moisture contents (50 and 60%). however, the extruded SPI at 40% moisture content had lower integrity index and cutting strength than those of the extruded SPI at other moisture contents (50 and 60%). In conclusion, the physical properties of extruded SPI were more affected by moisture content than screw speed.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.3
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• pp.625-633
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• 2015

Olive flounder (Parlichthys olivaceus) is a large carnivorous fish that live at coastal area and shallow seas in Korea. It was good texture and clean taste because of a high collagen content and low lipid content. More than 70% of olive flounder annual production was traded alive, consequently processing food product from olive flounder is rare to be towed. This study was conducted to investigate the best method of olive flounder cutlet processing. Clean fillet (headless, skinless and contain no viscera part) of olive flounder were divided into 5 portion. Every 100 g of olive flounder meat was wrapped with vinyl then flatten with meat hammer. Flatten fillet then was coated with wheat flour, and seasoned with salt and pepper. These were then coated with egg wash and bread crumbs. Two different method of processing was to make this olive flounder cutlet. Cutlet-1 was fried for 1 min in olive oil, then kept in polyethylene film vacuum packaging ($20{\times}30{\times}0.05mm$) and stored at $-20^{\circ}C$ for 7 days. After 7 days the cutlet was thawed and heat up in microwave for 2 min (Sample-1). The other proup is cutlet-2, which is directly stored in polyethylene film vacuum packaging at $-20^{\circ}C$ for 7 days then thawed and fried for 1 min in olive oil (Sample-2). The factors such as pH, TBA value, amino-N, free amino acid, chemical composition, color value (L, a, b), texture profile, sensory evaluation and viable bacterial count of the olive flounder cutlet (Sample-1, Sample-2) were measured. From the result of sensory evaluation, Sample-2 showed a little high scores than Sample-1. But there was no significant differences in color, odor, taste, texture and overall acceptance between Sample-1 and Sample-2 products.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.2
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• pp.112-120
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• 2014

Purpose: This study compared the shear bond strength of heat pressed and feldspathic porcelain to metal. Through thermocycling, the clinical aspect of heat pressed porcelain fused metal was estimated. Materials and Methods: 90 non-precious metal specimens were made ($4{\times}4{\times}8 mm$) and divided to three groups. All spicimens were treated and built-up with the porcelain ($4{\times}4{\times}3 mm$) by 2 different methods according to group: Group I: $Inspiration^{(R)}$, Group II: Ivoclar, IPS $Inline^{(R)}PoM$, Group III: GC Initial IQ-One $Body^{(R)}PoM$. The half of each group's specimens were thermocycled. All specimens' shear bond strength were measured by Instron universal testing machine. Exact measuring point was far 1 mm from porcelain/metal interface to the porcelain side. For the statistical analysis, 2-way ANOVA was used. Results: In no-thermocycling specimens, the shear bond strength showed no statistical significance between each group (P > 0.05). In comparison between nothermocycling and thermocycling specimens in each group, the shear bond strength was decreased according to thermocycling, but there was no statistical significance (P > 0.05). In thermocycling specimens, there was no statistical significance between each group (P > 0.05). Conclusion: In feldspathic porcelain and other two types heat pressed porcelain, there was no statistical difference in the shear bond strength of porcelain to metal. The heat pressed porcelain seems to be clinically useful for the aspect of the shear bond strength.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.11 no.1
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• pp.50-62
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• 1989

This is clinicostatistical study of mandibular fractures. This study was based on a series of 677 patients with mandibular fracture during the period of 1982 to 1987. This results obtained were as follows : 1. In respect of incidence, there were high frequency in May and September, and in large city(63%). 2. The age frequency was the highest in the 20s-year old group (38.7%), and the ratio of male to female was 4.64 : 1. 3. The most common etiologic factor was blow(31.5%), but in children that was traffic accident followed by fall down. 4. The most common site of bone fractures was symphysis, followed by angle, condyle. In comparison of right and left sides, left side was more frequently involved(364 cases) than right side(257 cases). 5. The patients arrived in hospital immediately within 24 hours after accident were 62.9% of all, and 42.4% was arrived via private medical and dental clinic. 6. In respect of treatment, open reduction was 55.5% of all, closed reduction was 37.2%. In children, closed reduction was done in 50.6%.

• Restorative Dentistry and Endodontics
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• v.30 no.2
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• pp.128-137
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• 2005

In this study we measured the amount of light energy that was projected through the tooth material and analyzed the degree of polymerization by measuring the surface hardness of composites. For polymerization, Optilux 501 (Demetron, USA) with two types of light guide was used: a 12 mm diameter light guide with 840 nW/$cm^2$ light intensity and a 7 mm diameter turbo light guide with 1100 nW/$cm^2$. Specimens were divided into three groups according to thickness of penetrating tooth (1 mm, 2 mm, 0 mm). Each group was further divided into four subgroups according to type of light guide and curing time (20 seconds, 40 seconds). Vickers' hardness was measured by using a microhardness tester. In 0 mm and 1 mm penetrating tooth group, which were polymerized by a turbo light guide for 40 seconds, showed the highest hardness values. The specimens from 2 mm penetrating tooth group, which were polymerized for 20 seconds, demonstrated the lowest hardness regardless of the types of light guides (p < 0.05). The results of this study suggest that, when projecting tooth material over a specified thickness, the increase of polymerization will be limited even if light intensity or curing time is increased.