• Journal of Biosystems Engineering
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• v.26 no.2
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• pp.177-188
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• 2001

This research was carried out to examine the optimum design conditions of a vertical small-scale milling machine where the rough rice is processed directly into the white rice in one pass. Effects of the main spindle speed, feed screw pitch and ceramic coating length of the roller on various milling characteristics such as white rice processing capacity, electric energy consumption, rice temperature increase, broken rice ratio, moisture reduction, outlet force and crack ratio increase were studied. The results are as follows. 1. The maximum white rice processing capacity and the lowest crack ratio increase, were obtained from a machine with specification: main spindle speed of 970rpm having a feed screw pitch of 19㎜. 2. The minimum electric energy consumption was obtained with the main spindle speeds of 900 and 970rpm respectively having a feed screw pitch of 19㎜. 3. The rice temperature was increased as the feed screw pitch decreased and the main spindle speed increased. 4. Broken rice ratio was relatively low with the range of 0.8∼1.3%. 5. Moisture content loss was with the range of 0.05∼0.4%. 6. The highest outlet force was 0.72kg$\_$f/ with 900rpm of the main spindle speed and 19㎜ of the feed screw pitch and the lowest outlet force was 0.18∼0.34kg$\_$f/ with 970rpm of the main spindle speed and 16㎜ of the feed screw pitch. 7. The optimum design conditions for the vertical small-scale milling machine were obtained at 970rpm of the main spindle speed, 19㎜ of the feed screw pitch and 20㎜ of the ceramics coating length.

• Journal of Welding and Joining
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• v.14 no.6
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• pp.109-118
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• 1996

Al$_2$O$_3$-TiO$_2$powders of six different compositions were plasma-sprayed on Ti substrate. The spray powders and the spray coated layers were analysed and compared using SEM and X-RD. The elastic properties (specific elastic constant and damping coefficient) of the coated specimens were measured in order to select the optimum composition range of ceramics for use in a speaker diaphragm. A correlation between the microstructure and elastic properties was also investigated. When $Al_2$O$_3$powders with 0- 13% TiO$_2$were plasma sprayed, the coated layers were composed of metastable y-Al$_2$O$_3$with small amount of $\alpha$-Al$_2$O$_3$and the content of $\alpha$-Al$_2$O$_3$was increased with TiO$_2$content. Specific elastic constant was rapidly increased with 2 and 13% TiO$_2$addition to $Al_2$O$_3$. The internal damping was nearly unchanged with TiO$_2$content The specific elastic constant seemed to be dependent on the content of $\alpha$-Al$_2$O$_3$in the coated layer.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.306-310
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• 1998

The soluble polyimides(PMDA/diamine/dianhydride) were prepared and investigated. After coating the prepared PMDA/diamine/dianhydride solution into the commercial tubular alumina ceramic membranes, gas permeation characteristics was investigated. $T_g{\prime}s$ of the polyimides were in the range of $337{\sim}358^{\circ}C$ and thermal stability was good. The polymer was soluble in NMP, DMAc, DMSO, THF, and m-cresol. The adhesion between the alumina membrane and the soluble polyimide was excellent. The soluble polyimide/alumina membranes containing 6FDA showed the highest permeability among others. The permeability of nitrogen of PMDA/1,3PDA/6FDA-alumina membrane was about $7.6{\times}10^{-7}(mol/m^2{\cdot}Pa{\cdot}s)$ in the gas permeation experiments. The ideal separation factor of $O_2/N_2$ and $H_2/N_2$ in PMDA/1,3PDA/6FDA-alumina membrane were 6.19, and 70.0, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.210-210
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• 2008

에어로졸 증착법은 상온에서 다양한 기판 상에 고밀도의 세라믹 후막을 코팅할 수 있는 최신 기술로써 다양한 방면으로의 응용이 개대되고 있다. 본 실험에서는 ADM을 이용하여 고주파수 영역에서 사용가능한 기판소재 제조에 관한 연구를 진행하였다. ADM을 통해 형성된 $Al_2O_3$ 막의 유전율은 9-10으로 bulk 시료와 비슷한 특성을 보였으나 후막의 손실률의 경우는 bulk 시료에 비해 상당히 컸으며 주파수 증가에 따라 그 값이 크게 감소하는 경향을 보였다. 본 실험에서는 ADM으로 형성된 $Al_2O_3$의 높은 손실률의 원인에 대해 고찰하고 ADM 을 통해 기판소재로 사용가능한 저손실의 $Al_2O_3$막의 제조를 위한 방법을 제시하고자 하였다.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.663-669
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• 2009

The honeycomb adsorbent was prepared for adsorbing and seadsorbent was prepared by using zeolite sheet, which contained zeolite as component. The steady-state adsorption properties and surface morphologies were analyzed and breakthrough characteristics were ananlyzed by providing 16% carbon dioxide mixed gas. By thermal regeneration, carbon dioxide concentration properties were analyzed, and the adsorptive separation process was compared between thermal swing adsorption and pressure swing adsorption after adsorbent temperature change during heating. The breakthrough results of the honeycomb showed possibility parating carbon dioxide from combustion exhaust gas, which had deep impact on climate change, and the characteristics of the adsorbent were studied. Na-X zeolite was coated on a honeycomb prepared with ceramic sheet or active carbon sheet so that the two honycomb can be used at high temperature. Third honeycomb of rotary adsorptive concentration process.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.330-331
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• 2011

희토류 이온이 첨가된 형광체는 조명, 정보 디스플레이, 태양 에너지 변환 소자에 응용 가능하기 때문에 상당한 주목을 받고 있다. 특히, 결정 입자의 형상과 크기는 산업체 응용에 있어서 중요한 변수 중의 하나이다. 구형의 형광체 입자는 형광층의 광학 및 기하학적 구조를 최적화 시킬 수 있고, 결정 입자의 크기는 양질의 코팅을 위해 필요한 결정 입자의 양에 영향을 미친다. 본 연구에서는, $YVO_4$ 모체 결정에 Eu 이온의 농도를 선택적으로 주입하여 발광 효율이 높은 적색 형광체를 합성하고자 한다. 형광체 분말 시료는 활성체인 Eu의 함량을 0.00, 0.05, 0.10, 0.15, 0.20 mol로 변화시키면서 고상 반응법을 사용하여 합성하였다. 볼밀링 작업을 수행한 후에, 60$^{\circ}C$에서 20시간 건조하였고, 잘게 갈아서 체로 걸러낸 다음에 세라믹 도가니에 넣고 전기로에서 서서히 온도를 승온시켜 500$^{\circ}C$에서 10시간 동안 하소를 실시한 후에 1,100$^{\circ}C$에서 5시간 동안 소결하였다. Eu 이온의 함량비를 변화시켜 합성한 $YVO_4$ : Eu 형광체 분말 시료의 발광 세기의 변화, 결정 구조와 표면 형상을 각각 PL과 PLE, XRD, FE-SEM 장치를 사용하여 측정한 결과들을 종합해 볼 때, Eu 이온의 비가 0.15 mol일때 발광 세기가 최대값을 나타냄을 알 수 있었으며, 더욱 Eu의 함량을 증가시키자 농도 억제 현상에 의하여 발광 세기는 급격히 감소함을 보였다. SEM으로 촬영한 결정 입자의 형상의 경우에, Eu 이온의 함량비가 증가함에 따라 결정 입자들이 더욱 조밀하게 구형에 가까운 형상을 나타냄을 관측할 수 있었다(Fig. 1). 형광체 분말의 형광 스펙트럼의 경우에, 619 nm에 주 피크를 갖는 적색 형광 스펙트럼들이 관측되었으며, Eu 이온의 함량비에 따라 형광 세기는 상당한 의존성을 나타내었다(Fig. 2). Eu 함량에 따른 결정입자의 크기, 형광 세기와 회절 피크의 반치폭 사이의 상관 관계를 제시하고자 한다.

• Polymer(Korea)
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• v.35 no.5
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• pp.375-377
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• 2011

$PbTiO_3$/P(VDF/TrFE) 0~3 composites thin films with 0.10 and 0.13 of ceramic volume fraction factor have been fabricated by two-step spin coating technique and analyzed. 0~3 connectivity of $PbTiO_3$/P(VDF/TrFE) composites film was observed successfully by SEM micrography. The SEM picture confirmed 0~3 connectivity. And, in all the properties, 0~3 $PbTiO_3$/P(VDF/TrFE) composites film was superior to P(VDF/TrFE) copolymer. Therefore, with a good low-dielectric constant and a high pyroelectric coefficient, the composite thin films can be used for a new pyroelectric infrared sensor of higher performance.

• Journal of the Korean institute of surface engineering
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• v.48 no.6
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• pp.315-321
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• 2015

Rare-earth zirconates, such as $La_2Zr_2O_7$ and $Gd_2Zr_2O_7$, have been investigated as one of the candidates for replacing conventional yttria-stabilized zirconia (YSZ) for thermal barrier coating (TBC) applications at higher turbine inlet temperatures. In this study, double-ceramic-layer (DCL) TBCs of YSZ 1st layer and $La_2Zr_2O_7$ top coat layer are fabricated by suspension plasma spray with serial liquid feeders. Microstructures, hardness profiles, and thermal durability of DCL-TBCs are also characterized. Fabricated DCL-TBCs of YSZ/$La_2Zr_2O_7$ exhibit excellent properties, such as adhesion strength (>25 MPa) and electrical thermal fatigue (~1429 cycles), which are comparable with TBCs fabricated by atmospheric plasma spray.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.35-39
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• 1997

스키는 겨울철에 하는 옥외 스포츠로서, 때로는 -30 .deg. C 정도의 저온이나 강풍이 부는 한냉 환경하에서 행하여지는 경우도 있다. 이러한 한냉환경은 신체기능을 저하시켜서 불쾌감을 증가시키므로 의복의 중요성이 더욱 강조된다. 인간과 환경 사이에 놓여 있는 스키웨어는 그 시대의 세련된 패션성이 요구될 뿐만 아니라 운동기능성, 안전성, 내구성 그리고 쾌적성을 구비하지 않으면 안된다. 따라서 환경이 인체에 미치는 영향이나 인간의 생리적 메커니즘을 인식하므로서 비로서 쾌적한 스키웨어를 만들 수 있는 것이다. 다양한 형태의 삶을 추구하는 현대인들의 관심은 점차 여가 시간의 건전한 활용 및 스포츠에 집중 되고 있다. 이러한 사회적인 경향에 발 맞추어 신소재의 스키웨어의 개발이 활발히 진행되고 있다. 예컨데 태양 광선을 흡수하는 세라믹 투입의 신소재의 개발과 체내에서 방출하는 열을 가능한 발산하지 않는, 두 가 지 기능을 합한 축열보온 소재의 스키웨어와 또 탁월한 방수. 방풍의 효과와 운동시 발생되는 수분. 열 배출 을 위한 투습의 능력이 있고 보온의 효과가 매우 높은 힐스포(HEALSPO) 코팅 소재를 사용한 스키웨어도 개발 되고 있다. 그리고 보온성과 심리적 만족감을 위한 원피스, 투피스, 쓰리피스 타입의 디자인 개발도 진행되 고 있다. 본 연구에서는 한냉하 운동시의 축열보온 소재 및 힐스포 소재와 같은 특수소재 스키웨어가 인 체에 미치는 영향을 다른 일반 소재와 비교 고찰하고, 스키웨어의 디자인에 대한 보온성의 효과를 검토하기 위하여, 저온환경에서의 피험자의 온열생리학적 반응을 측정하였다.한 신장/근력 팀의 경우보다 높은 에너지 소비량과 심박수를 보였다.찰한 결과, 세포독성 및 염색체 이상을 유발하지 않았다. 또한 동물약품으로 사용되는 치료용량 및 투약방법에 근거하여 10mg/kg 및 5, 2.5mg/kg을 1일 1회씩 4회 투여한 군에서도 암수에 상관없이 전 농도 군에서 염색체이상을 나타내지 않아 유전독성을 나타내지 않음을 관찰하였다. 특히 vitamin C와 E의 병용투여는 상승적으로 적용하여 간세포손상을 더욱 억제시킴을 알 수 있었다.mance and on TFP(Total Factor Productivity) growth which is a pure measure of firm performance. To utilize the advantage of panel data, FEM(Fixed Effect Model) and REM(Random Effect Model) were used. The empirical result shows that the entropy index as a measurement of inter-business relatedness is not significant but technological relatedness index is significant. OLS estimates on pooled data were considerably different from FEM or REM estimates on panel data. By introducing interaction effect among the three variables for business

• Journal of Auto-vehicle Safety Association
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• v.7 no.3
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• pp.14-18
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• 2015

Toughened glass is known to have about four times larger external impact resistance than that of original glass. This study is aimed to verify that ceramic-printed toughened glass does not meet of GTR(Global Technical Regulations) No. 6 and its strength is lower than that of original glass through tests. The tests were conducted on the test pieces of original glass, toughened glass, and ceramic-printed toughened glass from five glass manufacturers. In Test 1, a 227g steel ball was dropped from a height of 2 meters, and damage was checked according to the test method of GTR No. 6. In Test 2, a steel ball was freely dropped from different heights and limited damage height was determined. In the result of Test 1 according to the test method of GTR No. 6, while all five test pieces of toughened glasses were not damaged, all the ceramic-printed toughened glass from the five manufacturers were damaged. In the result of Test 2, none of the five test pieces of toughened glass were damaged by a 10m ball drop, meanwhile, the original glasses were damaged by an average of 3m ball drop. And the results of the tests show that the ceramic-printed toughened glass does not have the features of toughened glass due to its very low strength. Therefore, this study contributes to the safety of consumers by considering the GTR No. 6, and by revising the toughened glass test method.