• Journal of the Korean Magnetics Society
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• v.25 no.4
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• pp.101-105
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• 2015

Recent theoretical calculations predicted that a system composed exclusively of 3d transition metals without 4d/5d transition metals or rare earth metals can have strong perpendicular magnetocrystalline anisotropy (MCA) if Fe and Ni layers are arranged appropriately. They considered only Fe-terminated surfaces, noting that Fe/MgO(001) and CoFeB/MgO(001) show strong perpendicular MCA. In this paper, we investigate magnetism and MCA of Ni/Fe(001) surface where Ni layer is positioned at the surface, by using complementarily the first principles calculational methods of Vienna Ab-initio Simulation Package (VASP) and Full-potential Linearized Augmented Plane Wave (FLAPW) method. Comparing results of magnetism and MCA obtained by VASP with the results by FLAPW method, we find the VASP results do not show big difference from results by FLAPW method. Magnetic moments of Fe and Ni are enhanced due to strong hybridization between Fe and Ni bands. MCA of Ni/Fe(001) is parallel to the surface, which implies the surface termination plays a crucial role in determining MCA of a system.

• Journal of Adhesion and Interface
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• v.24 no.4
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• pp.136-142
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• 2023

In this study, TEOS was used as a silica source, and a triblock copolymer (P123) was used as a template to produce mesoporous silica with a well-ordered hexagonal mesopore array through a self-assembly method and hydrothermal process under acidic condition. (Surfactant-extracted SBA-15). Surfactant-extracted SBA-15 showed the particle shape of a short rod with a size of approximately 980 nm. The surface area and pore diameter were 730 m²g^-1 and 70.8 Å, respectively. Meanwhile, aminosilane (3-aminopropyltriethoxysilane, APTES) was grafted into the mesopores using a post-synthesis method. Mesoporous silica (APTES-SBA-15) modified with aminosilane had a well-ordered pore structure (p6mm) and well-maintained the particle shape of short rods. The surface area and pore diameter of APTES-SBA-15 decreased to 350 m²g^-1 and 60.7 Å, respectively. APTES-modified mesoporous silica was treated with a solution of rare earth metal ions (Eu³⁺, Tb³⁺) to synthesize a mesoporous silica material in which rare earth metal complexes were introduced into the mesopores. (Eu/APTES-SBA-15, Tb/APTES-SBA-15) These materials exhibited characteristic photoluminescence spectra by λ_ex=250 nm. (⁵D₄→⁷F₅ (543.5 nm), ⁵D₄→⁷F₄ (583.5 nm), ⁵D₄→⁷F₃ (620.2 nm) transitions for Tb/APTES-SBA-15; ⁵D₀→⁷F₀ (577.7 nm), ⁵D₀→⁷F₁ (592.0 nm), ⁵D₀→⁷F₂ (614.9 nm), ⁵D₀→⁷F₃ (650.3 nm) and ⁵D₀→⁷F₄ (698.5 nm) transitions for Eu/APTES-SBA-15)

• Resources Recycling
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• v.23 no.2
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• pp.3-16
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• 2014

Car exhaust $CO_2$ gas reduction and fuel efficiency of the car lighter for the current era is a big challenge. The developments of high-performance Nd magnets, Li-ion secondary battery and exhaust gas purification performance of PGM catalysts used in the lightweight EV and HEV are activated. Country in order to improve the car lighter and function that use the resources of rare metals are ubiquitous imported from China because of export supply control, as soaring prices have unstable supply and demand. Compared to the emissions from the next-generation automotive recycling, waste scarce resources need to be. This study investigated the recycling technology analysis and development of the information technology, or delivered to the researchers by giving national car industry aims to contribute to the development. Findings, pulmonary high-performance motor vehicle emissions in the exhaust gas purification PGM Catalysts, Li-ion battery and Nd magnets recycling technology, such as pre- and post-processing techniques to classify technology, pre-urban mining technology mechanical separation by screening techniques under development, the study and post-processing technology has, pyro and hydro metallurgical smelting technology is established. Waste Recycling in terms of economic efficiency of mechanical components for the intensive study of screening techniques is needed.

• Resources Recycling
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• v.21 no.4
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• pp.76-85
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• 2012

Fluorescent lamps generally involve mercury within their lamp bulbs. Thus if the lamps are disposed as they are, it might cause environmental pollution. On the other hand, as the life of the lamps depends on the degradation of the discharge performance, the fluorescent substance composing the fluorescent substance coating can be recycled by reusing them as the recycled fluorescent substance. Also, the glass material composing the glass bulbs can be reused. The range of search was limited in the open patents of USA (US), European Union (EU), Japan (JP), Korea (KR) and SCI journals from 1977 to 2011. Patents and journals were collected using key-words searching and filtered by filtering criteria. The trends of the patents and journals was analyzed by the years, countries, companies, and technologies. Recovery method of metals from spent fluorescent lamps is mainly the focus on the recovery of precious metals using acid treatment and, detoxification technology is related with controlling process of mercury using a filter system.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.1
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• pp.1-7
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• 2007

Electrorefining experiments were successfully carried out in LiCl-KCl eutectic molten salt with a graphite cathode. It was found that the formation of Uranium-Graphite intercalation compound(U-GIC) helped the self-scraping mechanism of the uranium dendrite and the efficiency of the electrorefiner increased due to an elimination of the stripping step. The contaminations of the uranium deposit by rare earth elements was negligible while about 300 ppm of carbon was observed. The carbon contamination is believed to be eliminated by further purification by yttrium reaction. The morphology characteristics of the recovered U deposit was compared to that of steel cathode. These are only qualitative preliminary experimental results, but we believe that further research on this type of activity change the direction of the electrorefining research on spent nuclear fuel.

• Journal of Environmental Science International
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• v.5 no.2
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• pp.211-220
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• 1996

New thin-and diselena-crown ethers containing two suffer and selenium donor atoms have been prepared. And then, mercury ($Hg^{2+}$) ion-selective electrodes with PVC-plasticizer (STPB) based on some macrocycles as neutral carriers were also made. The electrochemical selectivities for various ions, and the effects for macrocycles, matrix of membranes, ratio of plasticizer to macrowcles, concentration and pH of test solution were investigated on the $Hg^{2+}$ ion-selective electrodes. The 1, 10-diselena-18-crown-6-PVC-STPB (sodium tetraphenylborate) exhibited good linear responses of ${28.2}\pm{0.6}$ decade-1 for $Hg^{2+}$ ion in the conientration ranges of $10^{-2}~10^{-6}$ M $Hg^{2+}$ ion. This electrode exhibited comparatively good selectivities for $Hg^{2+}$ ion in comparison with alkali and alkaline earth metal ions, some heavy metal ions and rare earth metal ion in the range of pH 2.5~6.0. In addition, this electrode was applied as a sensor in the titration of $Hg^{2+}$ ion with $1^-$ ion in water.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.1
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• pp.71-76
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• 2010

The electrorefining process, one of main processes which are composed of pyroprocess to recover the useful elements from spent fuel, and the domestic development of electrorefiner have been reviewed. The electrorefiner is composed of an anode basket containing reduced spent fuel such as uranium, transuranic and rare earth elements, and a solid cathode, which are in LiCl-KCl eutectic electrolyte. Oxidation (dissolution) reaction occurs on the anode and a pure uranium is electrochemically reduced (deposited) on the solid cathode. By application of graphite cathode, which has a self-scrapping characteristics for the uranium deposits, and a recovery of the fallen deposits by a screw conveyer, a high-throughput continuous electrorefiner with a capacity of 20 kgU/day has been developed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.1
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• pp.29-34
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• 2008

In this paper, we investigated electrical and physical characteristics of nickel silicide using rare-earth metals(Er, Yb, Tb, Dy), Incorporated Ytterbium into Ni-silicide is proposed to reduce work function of Ni-silicide for nickel silicided schottky barrier diode (Ni-silicided SBD). Nickel silicide makes ohmic-contact or low schottky barrier height with p-type silicon because of similar work function (${\phi}_M$) in comparison with p-type silicon. However, high schottky barrier height is formed between Ni-silicide and p-type substrate by depositing thin ytterbium layer prior to Ni deposition. Even though the ytterbium is deposited below nickel, ternary phase $Yb_xN_{1-x}iSi$ is formed at the top and inner region of Ni-silicide, which is believed to result in reduction of work function about 0.15 - 0.38 eV.

• Transactions of the Korean hydrogen and new energy society
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• v.8 no.2
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• pp.67-78
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• 1997

현재 가장 널리 사용되고 있는 2차 전지는 Ni/cd 전지이며 카드뮴 전극의 사용으로 인해 공해 유발 문제를 가지고 있다. 그에 따라 공해 유발문제가 작은 전지를 제작하고자 하는 연구가 전세계적으로 진행되었고, 결과적으로 NiMH 전지가 개발되었다. 그러나 NiMH 전지에 사용되는 MH 전극은 희토류 토금속을 사용하기 때문에 전극 제작 비용이 비싼 단점을 가지고 있다. 본 실험에서는 자연 중 존재량이 많은 철 화합물을 음극 물질로 이용하여 공해 유발 문제와 제작비용 문제에 대한 대안을 제시하고자 하였다. 전지의 양극 물질은 Kamath에 의해 개발된 ${\alpha}-Ni(OH)_2$의 합성법을 응용, 제작하였다. 제작된 ${\alpha}-Ni(OH)_2/{\gamma}-FeOOH(an)$ 전지의 충 방전 및 전기화학적 특성을 조사하여 보고하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.508-508
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• 2011

스퍼터링을 이용한 박막 증착기술은 다양한 분야에 걸쳐 적용되어 왔으며, 스퍼터링 타겟 사용효율을 향상시키기 위해 마그네트론 구조 최적화 및 이온 소스 적용 스퍼터링 등의 기술이 연구되어 왔다. 또한 인듐과 같은 희토류 금속의 가격이 최근 상승함에 따라 고효율 스퍼터링기술의 필요성은 더욱 증대되었다. 본 연구에서는 고밀도 플라즈마 소스를 적용한 고효율 스퍼터링 공정을 개발하였다. 동공 음극방전에서 생성된 고밀도 플라즈마는 전자석 코일을 통해 형성된 자기장을 따라 스퍼터링 타겟 표면까지 수송되며, 음전위로 대전된 스퍼터링 타겟 표면에서는 가속되어 입사하는 이온에 의한 스퍼터링이 발생한다. 본 스퍼터링 공정 기술의 경우, 기존 마그네트론 스퍼터링 소스에서 나타나는 약 30%의 타겟 사용 효율을 뛰어넘는 약 80% 이상의 타겟 사용률을 보였다. 또한 고밀도 플라즈마 소스에서 공급되는 이온에 의한 스퍼터링 공정을 개발 함에 따라 스퍼터링 방전전압의 독립적 조절이 가능하다. 이에 따라 200 V 이하의 저전압 스퍼터링 공정을 통해 유연성 폴리머 기판 및 유기소자 상 저에너지 이온 증착이 가능하며, 1 kV 이상의 고전압 스퍼터링을 통해 추가적인 기판 전압 인가 없이 박막 치밀화 구현이 가능하다.