• Journal of the Korean Electrochemical Society
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• v.26 no.1
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• pp.1-10
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• 2023

The cathode, which is one of the four major components of a lithium secondary battery, is an important component responsible for the energy density of the battery. The mixing process of active material, conductive material, and polymer binder is very essential in the commonly used wet manufacturing process of the cathode. However, in the case of mixing conditions of the cathode, since there is no systematic method, in most cases, differences in performance occur depending on the manufacturer. Therefore, LiMn₂O₄ (LMO) cathodes were prepared using a commonly used THINKY mixer and homogenizer to optimize the mixing method in the cathode slurry preparation step, and their characteristics were compared. Each mixing condition was performed at 2000 RPM and 7 min, and to determine only the difference in the mixing method during the manufacture of the cathode other experiment conditions (mixing time, material input order, etc.) were kept constant. Among the manufactured THINKY mixer LMO (TLMO) and homogenizer LMO (HLMO), HLMO has more uniform particle dispersion than TLMO, and thus shows higher adhesive strength. Also, the result of the electrochemical evaluation reveals that HLMO cathode showed improved performance with a more stable life cycle compared to TLMO. The initial discharge capacity retention rate of HLMO at 69 cycles was 88%, which is about 4.4 times higher than that of TLMO, and in the case of rate capability, HLMO exhibited a better capacity retention even at high C-rates of 10, 15, and 20 C and the capacity recovery at 1 C was higher than that of TLMO. It's postulated that the use of a homogenizer improves the characteristics of the slurry containing the active material, the conductive material, and the polymer binder creating an electrically conductive network formed by uniformly dispersing the conductive material suppressing its strong electrostatic properties thus avoiding aggregation. As a result, surface contact between the active material and the conductive material increases, electrons move more smoothly, changes in lattice volume during charging and discharging are more reversible and contact resistance between the active material and the conductive material is suppressed.

• Journal of Animal Science and Technology
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• v.45 no.6
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• pp.1079-1088
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• 2003

This study was conducted to test the efficacy of the automatic liquid feeder(designated as NLRI) developed by National Livestock Research Institute, Korea for 7-day old early-weaning piglets. The other automatic liquid feeder imported from USA(designated as IALF) was used for a comparative purpose. A total of sixty piglets of 7 days of age were allotted to three treatments. The control group of 20 piglets was raised by their own sows until 21 days of age, while others were shifted to automatic liquid feeders of either NLRI or IALF on 7 days of age and reared during 14 days post-weaning. After then, all the piglets were fed nutritionally identical mash diets until 70 days of age. Compared with control group, body weight of piglets reared on automatic liquid feeders were lighter(P〈0.05) at 21 days of age [5.55kg (control) vs 4.97 (NLRI) and 4.98kg (IALF)], while heavier(P〈0.05) at 70 days of age(24.82kg vs 30.17 and 29.42kg). The results indicated that pigs reared on liquid feeding showed higher(P〈0.05) average daily gain than control pigs during the whole experimental period [346.7g (control) vs 425.8 (NLRI) and 416.1g (IALF)], while no difference was found in feed/gain (1.67 vs 1.78 and 1.84). There was no difference in growth performance and incidence of diarrhea between two automatic liquid feeders, NLRI and IALF. Compared with control group, intestinal villi tended to be shorter in liquid feeding group during the first week, but were recovered within two weeks. The results suggest that the automatic liquid feeder newly developed by National Livestock Research Institute, Korea can be successfully used for rearing young piglets weaned at very early age.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.12
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• pp.1381-1389
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• 2003

컴퓨터와 첨단영상매체의 발달로 디자인 분야에서도 컴퓨터를 사용하여 색을 자유롭게 선택할 수 있는 그래픽 소프트웨어가 도입되고 있으나 영상정보의 색채 재현성과 영상입출력 장치의 다양화로 인한 색채 불일치에 대한 문제들이 극복해야할 시급한 과제로 부각되고 있다. 따라서, 색채 영상정보 입출력장치의 색채구현 성능과 인간의 색채인지 원리이론을 바탕으로 색보정 알고리즘이 발전하여 색보정 엔진의 개발이 국제적으로 활발히 진행되고 있는 연구 분야임에도 불구하고 국내에서는 그 연구사례가 상대적으로 극히 미비한 실정이며, 더욱이, CAD 시스템을 이용한 패션/텍스타일 디자인 분야에서는 이에 대한 연구가 거의 이루어지지 않고 있다. 본 연구에서는 염색 직물의 색을 CAD시스템을 이용하여 soft-copy로 재현하고 이것을 다시 hard-copy로 출력하여 물리적 측정치와 주관적 색채 인지도간의 일치도를 비교하고, 물리적, 주관적 색차의 한계치를 제시함으로써, 패션/텍스타일 디자인 CAD시스템 운용에 기초가 되는 자료를 제공하려 하였다. 연구의 절차는 객관적 측정과 주관적 평가 두 단계로 나누어 진행되었다 연구에 사용된 직물은 7가지 색상의 면 염직물로써, CAD시스템을 이용하여 각 직물당 5개의 soft-copy를 재현하고, 이것을 다시 hard-copy로 출력하여 spectrophotometer를 이용해 물리적 측정(ΔE, ΔL, Δc, Δh)을 실시하였다. 또한 주관적 평가에는 20명의 의류학 전공 학생들이 참여하였다. 결과 분석에는 분산분석과 Friedman분석이 사용되었다. 연구 결과 색차 측정에 대한 물리적 측정치와 1차 주관적 평가치 사이의 일치도는 90.5%로 나타났으며, 2차 주관적 평가치와의 rank order는 거의 일치하는 것으로 나타났다. 또한 주관적 평가에서 피험자들은 색차인지에 있어 CIELAB 색채공간의 각각의 색요소 차이보다는 전체 색차에 더 영향을 받는 것으로 나타났다.녹색콩풍뎅이의 유충에 의하여 피해를 받는 것이 확인되었다. 녹색콩풍뎅이 유충의 피해를 받은 금잔디는 황화되거나 시들음 증상이 있었고, 이듬해 봄에는 잔디의 회복이 지연되었다.ic conductivity. The changes of $varepsilon$′ and $varepsilon$" were well estimated with this modified Havriliak-Negami model.05). 상기의 결과를 토대로, 성장과 전어체내 지방산조성에 있어서 뱀장어 치어의 사료내 EPA와 DHA의 첨가효과 미약한 것으로 판단되며, 사료내 LNA (n-3)와 LA(n-6) HUFA을 각각 0.35%, 0.65% 첨가했을 때 WG, SGR, FE, PER이 가장 높았으나, 이전의 실험(Takeuchi, 1980)과 동일한 수준인 n-3와 n-6를 각각 0.5%씩 첨가한 실험구와는 유의적인 차이를 보이지 않았다. 이렇게 볼 때, 뱀장어 치어의 필수지방산은 LNA (n-3), LA (n-6)이고, 그 적정수준은 각각 0.35-0.5%, 0.5-0.65%임을 보여준다.George W, Bush)가 새로운 지도자로 취임하여 얼마 되지 않은 2001년 9월 11일 사상 초유로 본토에서 알 카에다 테러리스트 조직에 의해 공격받게 되었다. 뉴욕의 세계무역센터 빌딩 2개가 완전히 붕괴되고, 펜타곤에 민간 여객기가 충돌하여 많은 사람이 살상 당하고, 전체적으로 세계 80여 개국으로부터의 6천여 명이 살상되었다. 전 세계와 미국은 국제 테러리스트들의 야만적 행위에 대해 경악하고 이제 미국은 그 대외정책의 최우선순위를 국제 테러를 발본색원하는 것에 두게 되었다. 본 논문은 1998년 한국에서 새로이 출범한 김대중 행정부가 북한에 대해 실시한 포용정책이 어떠한 성과를 거두고 어떠한 문제점을 간과하고 있는가에 대해 논의하고, 대북 정책의 새로운 지평을 논의하는 것을 목적으로 하고

• Journal of the Korea Concrete Institute
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• v.15 no.1
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• pp.43-51
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• 2003

Recently, to consider financial and constructive aspect usage of Admixture such as Blast-Furnace Slag and Fly-Ash, are increased. Also the use of cold-weather-concrete is increased. Blast-Furnace Slag, a by-product of steel industry, have many advantage to reduce the heat of hydration, increase in ultimate strength and etc. But it also reduces early-age strength, so it is prevented from using of Blast-Furnace Slag at cold-weather-concrete. In this study, for the purpose of increasing usage of Blast-Furnace Slag at cold-weather-concrete, it is investigated the strength properties of concrete subjected to frost damage for the cause of early age curing. The factors of this experience to give early frost damaged were Freezing temperature(-1, -10, $-15^{\circ}C$), Early curing age(0, 12, 24, 48hour), Freezing times(0, 12, 24, 48hour). According to this study, if early curing is carried out before haying frost damage, the strength of concrete used admixture, subjected to frost damage, is recovered. And that properties are considered, the effect of using admixture like blast-furnace-slag, is very high

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.2
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• pp.104-115
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• 2018

Purpose: The purpose of this study is to evaluate the image acquisition ability of intraoral scanners by analyzing the comprehensiveness of scanned images from standardized model, and to identify problems of the model. Materials and Methods: Cast models and 3D-printed models were prepared according to international standards set by ISO12836 and ANSI/ADA no. 132, which were then scanned by model scanner and two different intraoral scanners (TRIOS3 and CS3500). The image acquisition performance of the scanners was classified into three grades, and the study was repeated with varying surface conditions of the models. Results: Model scanner produced the most accurate images in all models. Meanwhile, CS3500 showed good image reproducibility for angled structures and TRIOS3 showed good image reproducibility for rounded structures. As for model ingredients, improved plaster model best reproduced scan images regardless of the type of scanner used. When limited to 3D-printed model, powdered surface condition resulted in higher image quality. Conclusion: When scanning structures beyond FOV (field of view) in standardized models (following ISO12836 and ANSI/ADA 132), lack of reference points to help distinguish different faces confuses the scanning and matching process, resulting in inaccurate display of images. These results imply the need to develop a new standard model not confined to simple pattern repetition and symmetric structure.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.8
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• pp.478-488
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• 2017

Stormwater filtration is widely used for the urban runoff treatment. However, intensive maintenance and lack of information about the performance have resulted in an increased need of proper evaluation. In this study, the performance of an upflow stormwater runoff filtration system, consisting of a supporting unit and a filtration unit filled with a ceramic media, was investigated. The maximum head loss increase was about 3 cm under the suspended solid (SS) load of $30kg/m^2$ and the SS removal was more than 96%, when the filtration velocity was 20-40 m/h. The head loss and the porosity of the media can successfully be described by a power model. It was confirmed that the a significant amount of SS can effectively be removed at supporting unit, minimizing SS load to the filter media bed. Several backwashing strategies have been tested to establish the optimum condition. It was found that the stagnant water discharge is important to minimize the SS release immediately after backwashing. Also, the filter bed loaded with $400-450kg/m^2$ SS can almost completely be washed to reduce the head loss to the that of empty bed. The results in this study indicate that the upflow ceramic media filter is an excellent alternative to stormwater treatment, with high SS removal and long lifespan.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.10a
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• pp.60-61
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• 1996

염색폐수를 처리하기 위하여, 일반적으로 물리.화학적 공정과 호기성 생물학적 공정을 조합한 방법들을 사용하고 있다. 하지만 호기성 생물학적 공정은 난분해성 물질의 제거능력이 낮고, 염색폐수의 주된 오염원인 염료분자가 호기성 미생물에 대한 에너지원으로 적합하지 않아 분해되기 어려우며, 물리.화학적 공정을 이용한 처리방법으로도 높은 처리효율을 얻을 수가 없다. 이러한 문제점을 극복하기 위하여 염색폐수 처리에 혐기-호기공정을 이용하며, 혐기성 공정에서 생물학적으로 분해되기 어려운 고분자 물질들을 가수분해하여 생물학적으로 분해가능한 저분자물질로 전환시키고, 호기성 공정에서 저분자 물질을 효과적으로 처라할 수 있기때문에 기존의 염색폐수 처리공정에 비하여 훨씬 높은 처리효율을 얻을 수 있다. 특히, 혐기성 미생물은 호기성 미생물에 비하여 난분해성 물질에 대한 분해력이 높고, 생물독성 물질에 대한 내성이 강하기 때문에 수중생물에 유해한 염료를 함유한 염색폐수의 색도제거에 효과적인 것으로 기대된다. 또한, 막분리 공정은 유기물 및 미생물이 막표면에 축적, 증식함으로써 막세공에 막힘현상을 초래하여 역세척 등의 물리적인 방법이나 화학약품을 이용한 화학적 세척 방법으로도 투과플럭스의 회복이 불가능한 상태를 유발함으로 막의 수명을 단축시키는 원인이 된다. 따라서, 혐기-호기공정과 조합하면 색도성분 제거 및 막 오염의 원인이 되는 유기물 및 용존성 고형물을 제거하고, 막 오염의 억제를 통한 후 수염의 연장은 물론, 처리수의 수질향상에 활용될 수 있을 것으로 사료된다.1로 강구와 함께 공구강 vial에 장입 후, Spex mixer/mill을 이용하여 기계적 합금화 하였다. 기계적 합금화 공정으로 제조한 분말에 대한 X-선 회절분석과 시차 열분석으로 합금화 정도를 분석하였다. (Bi1-xSbx)2Te3 및 Bi2(Te1-ySey)3 합금분말을 10-5 torr의 진공중에서 300℃∼550℃의 온도로 30분간 가압소결하였다. 가압소결체의 파단면에서의 미세구조를 주사전자현미경으로 관찰하였으며, 상온에서 가압소결체의 열전특성을 측정하였다. (Bi1-xSbx)2Te3의 기계적 합금화에 요구되는 공정시간은 Sb2Te3 함량에 따라 증가하여 x=0.5 조성에서는 4 시간 45분, x=0.75 조성에서는 5 시간, x=1 조성에서는 6 시간 45분의 vibro 밀링이 요구되었다. n형 Bi2(Te1-ySey)3 합금분말의 제조에 요구되는 밀링시간 역시 Bi2Se3 함량 증가에 따라 증가하였으며 Bi2(Te0.95Se0.05)3 합금분말의 제조에는 2시간, Bi2(Te0.9Se0.1)3 및 Bi2(Te0.85Se0.15)3 합금분말의 형성에는 3시간의 bivro 밀링이 요구되었다. 기계적 합금화로 제조한 p형 (Bi0.2Sb0.8)2Te3 및 n형 Bi2(Te0.9Se0.1)3 가압 소결체는 각기 2.9x10-3/K 및 2.1x10-3/K 의 우수한 성능지수를 나타내었다.ering)가 필수적이다. 그러나 침전법에서 얻게 되는 분말은 매우 미세하여 colloid를 형성하게 되며, 이러한 colloid 상태의 미세한 침전입자가 filte

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.1
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• pp.69-75
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• 2017

In this paper, slit ground resonator with slit and capacitor is proposed for practical use of magnetic resonant wireless power transfer(MR-WPT). And this paper presents the performance comparison of conventional loop resonator as Rx resonator to slit ground resonator. The proposed silt ground resonator with 31 cm width, 20.5 cm length, $35{\mu}m$ thickness is designed the crossing slit 1 cm width with only opened edge. And an external capacitors were connected at the opened edge of slit ground resonator for resonating at 6.78 MHz. The transfer efficiencies of MR-WPT were measured at open and short mode, and then the highest transfer efficiencies of MR-WPT according to the Rx resonators were plotted. In result, the transfer efficiency of MR-WPT with loop resonator was the highest. However, when the ground was inserted in receiver part at the bottom of laptop model, the transfer efficiency was closed 0 %. The transfer efficiency recovered the transfer efficiency of 67 % using slit ground resonator. The magnetic field was penetrated through the slit and proposed slit ground resonator works as resonator in MR-WPT.

• Progress in Medical Physics
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• v.20 no.3
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• pp.119-124
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• 2009

Stents are frequently used throughout the human body. They keep pathways open in vascular or nonvascular duct for a long time. Therefore its stability is very important factor. In recent years, aconsiderable amount of research has been carried out in order to estimate mechanical properties of the stent such as expansion pressure behavior, radial recoil and longitudinal recoil using FEM (Finite element analyses). However, published works on simulation of stent fatigue behavior using FEM are relatively rare. In this paper, a nonlinear finite-element methodwas employed to analyses the compression of a stent using external pressure and fatigue behavior. Finite element analyses for the stent system were performed using NASTRAN FX. In conclusion this paper shows how the stent is behaved in the body, and its fatigue behavior.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.881-890
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• 2005

Over for the past 10 years, the increase in geometric progression for the internet traffic, has allowed the IP protocol framework to be the most important network technology. In addition, the internet service is being developed as a service mode differentiated, aiming to support the new-mode real-time multimedia services such as internet phone, video conference, cyber reality, and internet game, focusing on offering a latest service. These days, aiming to solve the need for broad bandwidth along with guaranteeing QoS, the WDM technology of offering multiple gigabit wavelengths is emerging as the core technology of next-generation optical internet backbone network. In the next-generation optical internet backbone network based on WDM, the QoS framework is one of fore subjects aiming to offer a service of guaranteeing QoS This study analyzes the requirements of performance related to QoS framework in IP Subnet and in WDM optical backbone network, and suggests optical QoS service framework differentiated. in order to guarantee end-to-end QoS through the next-generation optical internet backbone network, using GMPLS control protocol.