• 한국세라믹학회지
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• 제37권5호
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• pp.466-472
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• 2000

As cathode materials of LiMn2O4-based lithium-ion secondary batteries, Li(Mn1-$\delta$M$\delta$)2O4 (M=Ni and Co, $\delta$=0, 0.05, 0.1 and 0.2) materials which Co and Ni are substituted for Mn, were syntehsized by the solid state reaction at 80$0^{\circ}C$ for 48 hours. No second phases were formed in Li(Mn1-$\delta$M$\delta$)2O4 system with substitution of Co. However, substitution of Ni caued to form a second phase of NiO when its composition exceeded over 0.2 of $\delta$ in Li(Mn1-$\delta$M$\delta$)2O4. As the results of charging-discharging test, the maximum capacity of Li(Mn1-$\delta$M$\delta$)2O4 appeared in $\delta$=0.1 for both Co and Ni. Also, Li(Mn1-$\delta$M$\delta$)2O4 electrode showed higher capacity and better cycle performance than LiMn2O4.

• 한국레이저가공학회지
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• 제17권3호
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• pp.1-9
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• 2014

In this study, we analyzed fiber laser welding for the pure copper thin plates in a series of secondary lithium-ion batteries; and performed the experiment for the purpose of the preceding study to replace bolt joints method the with the laser welding method. We have changed the peak power of the laser from 5 to 6kW, the pulse duration by 4, 6, 8, and 10ms, the frequency by 10, 12, 16, and 25Hz, and the focal position by -3, 0, and +3. As a result, when the focal position is at +3, the peak power is 5kW, and the pulse duration and the Frequency are 4ms and 25Hz, respectively, we obtain 2.1 and 2.5 times better tensional strengths, respectively, than the highest values of tensional strengths obtained with the focal positions at 0 and -3.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1571-1578
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• 2013

With the emergence of high-integration array and large area panel process, the need to minimize the generation of particles in the field of semiconductor, LCD and OLED has grown. As an alternative to the conventional roller system, a contactless magnetic conveyor has been proposed to reduce the generation of particles. An EM-PM hybrid which is one of magnetic levitation types is already proposed for the conveyor system. One of problems pointed out with this approach is the vibration caused by the dynamic interaction between conveyor and rail. To reduce the vibration, the introduction of a secondary suspension system which aims to decouple the levitation electromagnet from the main body is proposed. The objective of this study is to develop a dynamic model for the magnetically levitated conveyor, and to investigate the effect of the introduced suspension system. An integrated model of levitation system and rail based on 3D multibody dynamic model is proposed. With the proposed model, the dynamic characteristics of maglev conveyor system are analyzed, and the effect of the secondary suspension and the stiffness and damping are investigated.

• 한국정밀공학회지
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• 제29권10호
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• pp.1078-1088
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• 2012

In this paper, we present research experimental results about the different thickness T-joint welding of the high power continuous wave(CW) Nd:YAG laser for the secondary battery of a vehicle. Although the conventional method used for the secondary battery is a argon TIG welding, we utilize a laser welding to improve Tungsten Inert Gas(TIG) welding's weakness. The laser, which has a couple of advantage such as aspect ratio, low Heat Affected Zone(HAZ), good welding quality and fast productivity utilized in this work is a CW Nd:YAG laser. In order to observe laser welding sections, we used a optical microscope. Through the analysis of the metallographic, hardness, aspect ratio, and heat input, we obtained the desired data in condition of 1800 W laser beam power and 1.8 m/min and 2.0 m/min laser beam travel speeds. In order to compare electric resistances of the argon TIG welding and laser welding, we made an actual battery and the electric resistance of the laser welding is reduced by 40~45% comparing with the argon TIG welding.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.25-28
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• 1998

Lithiated cobalt and nickel oxides are becoming very attractive as active cathode materials for secondary lithium ion secondary battery. $LiCoO_2$ is easily synthesized from lithium cobalt salts, but has a relatively high oxidizing potential on charge. LiNiOz is synthesized by a more complex procedure and its nonstoichiometry significantly degraded the charge-discharge characteristics. But $LiNiO_2$ has a lower charge potential which increases the system stability. Lithiated cobalt and nickel oxides are iso-structure which make the preparation of solid solutions of $LiNi_{1-x}Co_xO_2$ for O$LiCoO_2 and LiNiO_2$ electrode. The aim of the presentb paper is to study the electrochemical behaviour, as weU as the possibilities for practical application of layered Iithiated nickel oxide stabilized by $Co^{3+}$ substitution as active cathode materials in lithium ion secondary battery.

• 자원리싸이클링
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• 제22권2호
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• pp.3-10
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• 2013

인듐은 희유금속으로 주로 ITO제조에 사용된다. 본 총설에서는 인듐을 함유한 2차자원을 침출한 용액으로부터 인듐을 분리하기 위한 용매추출, 이온교환 및 석출법에 대한 공정 조건 및 장단점을 조사했다. 보통 정도의 산성용액에서 인듐의 추출제로 D2EHPA가 가장 많이 사용되고 있으며, 매우 강한 염산용액에서는 아민계 추출제가 사용된다. 일반적으로 이온교환수지의 인듐 흡착량이 낮으므로, 인듐의 농도가 낮은 경우에 한해 이온교환은 용매추출보다 장점이 있다.

• Carbon letters
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• 제25권
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• pp.84-88
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• 2018

At present, an important research area is the search for materials that are compatible with CMOS technology and achieve a satisfactory response rate and modulation efficiency. A strong local field of graphene surface plasmon polariton (SPP) can increase the interaction between light and graphene, reduce device size, and facilitate the integration of materials with CMOS. In this study, we design a new modulator of SPP-based cycle branch graphene waveguide. The structure comprises a primary waveguide of graphene-$LiNbO_3$-graphene, and a secondary cycle branch waveguide is etched on the surface of $LiNbO_3$. Part of the incident light in the primary waveguide enters the secondary waveguide, thus leading to a phase difference with the primary waveguide as reflected at the end of the branch and interaction coupling to enhance output light intensity. Through feature analysis, we discover that the area of the secondary waveguide shows significant localized fields and SPPs. Moreover, the cycle branch graphene waveguide can realize gain compensation, reduce transmission loss, and increase transmission distance. Numerical simulations show that the minimum effective mode field area is about $0.0130{\lambda}^2$, the gain coefficient is about $700cm^{-1}$, and the quality factor can reach 150. The structure can realize the mode field limits of deep subwavelength and achieve a good comprehensive performance.

• 한국세라믹학회지
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• 제47권2호
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• pp.163-168
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• 2010

Effects of compositions on the microwave dielectric properties of the MgO-$TiO_2$ system were investigated as a function of the molar ratio of MgO to $TiO_2$ ($0.9{\leq}MgO/TiO_2\;(x){\leq}1.2$). With the compositional changes, secondary phases of $MgTi_2O_5$ and $Mg_2TiO_4$ were also detected along with $MgTiO_3$. Microwave dielectric properties of the specimens were dependent on the types of phases developed in the sintered specimens. A single phase of $MgTiO_3$ showed a dielectric constant (K) of 18.2, a quality factor (Qf) of 198,000 GHz, and a temperature coefficient of resonant frequency (TCF) of $-51\;ppm/^{\circ}C$. However, the dielectric properties of the specimens with a secondary phase of $MgTi_2O_5$ (K=19.9, Qf=48,000 GHz) and/or $Mg_2TiO_4$ (K=15.6, Qf=56,000 GHz) were worsened. Dependence of the microwave dielectric properties on the secondary phase of the MgO-$TiO_2$ system was also discussed in terms of dielectric mixing rules.

• 한국과학교육학회지
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• 제25권7호
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• pp.754-764
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• 2005

이 연구는 증등학생의 탐구능력 향상을 위한 실생활 소재 탐구모듈 개발 연구이다. 실생활소재를 사용하여 물, 열, 빛, 운동, 물질과 관련된 물리내용으로 모듈을 구성하였는데, 각 모듈 당 4-6개의 관련 활동들이 포함되어 있고, 각 모듈은 학생용 실험서와 교사용 지도서로 구성되어 있다. 모듈을 현장 물리 교사에게 워크삽을 통해 모듈의 목표, 내용, 활용 측면에서 타당도 평가를 받았는데, 모듈의 목표 측면에서는 79%의 긍정적인 평가를 받았고, 내용 측면에서는 77%, 활용 측면에서는 71 %의 긍정적인 평가를 받아, 전체적으로 74 %의 긍정적인 평가를 받았으며, 모듈의 개선점, 보완점등의 설문을 바탕으로 수정보완하여 모듈을 완성하였다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.173.2-173.2
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• 2016

A two-step oxidation method was applied on Al6061 to debate the growth mechanism of plasma electrolytic oxidation (PEO) coating. The specimens were first oxidized in the primary electrolyte solution {$Na_3PO_4$ (8g/l), NaOH (2g/l), consequently, the specimens were transferred into a different electrolyte {$K_2ZrF_6$ (8g/l), NaOH (2g/l), $Na_2SiF_6$ (0.5g/l)} for further oxidation. The processes was conducted for various processing times. It was found the second step electrolyte component were reached to inner layers, in contrast to the primary step components which were thrustle to the outer layer. The presence of the secondary component in the inner layers were significantly varied with processing time which suggest the change in growth properties with processing time. further more the inside growth of the secondary component confirmed the increasing trend in the downward growth of the coating layer. The corrosion and hardness properties of the coatings were found highly improved with change in growth features with increasing the processing time.