• Journal of the Korean Ceramic Society
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• v.41 no.10 s.269
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• pp.735-741
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• 2004

$LiMn_{1.92}Co_{0.08}O_4$ and $LiNi_{0.7}Co_{0.3}O_2$ synthesized by a simplified combustion method had good electrochemical properties. Mixtures $LiMn_{1.92}Co_{0.08}O_4$-x wt$\%$ $LiNi_{0.7}Co_{0.3}O_2$ (x=9, 23, 33, 41, and 47) were prepared by milling for 30 min and their electrochemical properties were investigated. The electrode with x=9 had a relatively large first discharge capacity (109.9 mAh/g at 0.1 C) and good cycling performance. The decrease in the discharge capacity of the mixture electrodes with cycling is considered to result mainly from the degradation of $LiNi_{0.7}Co_{0.3}O_2$, caused by coating of $LiNi_{0.7}Co_{0.3}O_2$ with Mn dissolved from $LiMn_{1.92}Co_{0.08}O_4$.

• Korean Journal of Materials Research
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• v.33 no.3
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• pp.95-100
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• 2023

This research examines the effect of adding aluminum on the structural, phasic, and magnetic properties of CoCrFe NiMnAl_x high-entropy alloys. To this aim, the arc-melt process was used under an argon atmosphere for preparing cast samples. The phasic, structural, and magnetic properties of the samples were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrational magnetometry (VSM) analyses. Based on the results, the addition of aluminum to the compound caused changes in the crystalline structure, from FCC solid solution in the CoCrFeNiMn sample to CoCrFeNiMnAl BBC solid solution. It was associated with changes in the magnetic property of CoCrFeNiMnAl_x high-entropy alloys, from paramagnetic to ferromagnetic. The maximum saturation magnetization for the CoCrFeNiMnAl casting sample was estimated to be around 79 emu/g. Despite the phase stability of the FCC solid solution with temperature, the solid solution phase formed in the CrCrFeNiMnAl high-entropy compound was not stable, and changed into FCC solid solution with temperature elevation, causing a reduction in saturation magnetization to about 7 emu/g.

• Proceedings of the Korean Magnestics Society Conference
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• 2000.09a
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• pp.327-328
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• 2000

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.190-191
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• 2002

Granular feromagnets는 non-magnetic maxtrix 안에 nanometer-sized의 ferromagnetic grain들 구성된다. Co-Cu,Co-Ag, Fe-Ag, NiFe-Ag $^1$을 포함하는 이미 알려진 다른 Granular 금속 합금들의 giant magnetoresistance 에 관계하여 Granular feromagnets 에 대해 조사하였다. Bulk상태의 NiFe와 Mn 혼화되기 쉽다.$^2$ 그리고 Mn은 열처리된 다층박막의 NiFe의 lattice에 쉽게 수용되어진다.$^3$ 이번 실험에서는 metastable한 fcc solid solution NiFe-Mn 박막이 열처리 하에서 NiFe과 Mn으로 분리되었다. (중략)

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.2
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• pp.119-126
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• 1979

Rice seeds, suweon 264, were germinated under 5 levels of toxic heavy metals, Cd(0, 0.05, 0.5, 5, 20ppm), Cu(0, 0.05, 0.5, 5, 20, ppm), Cr(0, 0.5, 1, 5, 10ppm), Ni(0, 0.5, 1, 5, 10ppm), Co(0, 0.5, 1, 5, 10ppm), Zn(0, 0.5, 5, 20, 40, ppm), Pb(0, 0.5, 5, 20, 40ppm) and Mn(0, 1, 10, 25, 50, ppm) in culture solution, and then grown with supplying culture solution contained respective concentrations. Germination and growth response to the toxic heavy metals were studied. Results obtained are as follows : 1) The germination injury of rice seeds by excess concentration of toxic heave metal in culture solution occured in Cd and Cu; below 0.05 ppm, Ni; below 0.5 ppm, Mn; below 1.0 ppm, Co and Cr; 0.5-1.0 ppm, and 0.5-5 ppm, Zn and Pb. Thereby, in the order of degrees of the elements toxicity to germination, they were arranged as follows : Cd>Cu>Ni>Co>Cr>Mn>Zn$$\geq_-$$Pb. 2) Toxic heavy metal concentrations in culture solution, which result in decreasing dry weight due to the injury of excess concentration of treated elements, were Cd: below 0.05 ppm, Ni, Cr and Co; below 0.5 ppm, Cu and Zn; 0.5-5 ppm, Pb; 5-20 ppm and Mn; 10-25 ppm. The order was Ni>Cd>Cr>Co>Cu$$\geq_-$$Zn>Pb>Mn. 3) The critical contents of Cd, Ni, Pb, Cu, Zn, Mn, and Co in dry matter, Which result in decreasing dry weight, were considered to be 0.05-15.5, 1.50-25.0, 24.0-28.0, 26.5-62.5, 470-645.0, 231.0-500.0 and below 15.0 ppm, respectively. 4) The contents of Cr, Co, Cd, Pb, Ni, Cu and Zn in dry matter by 0.5 ppm treatment concentration of each heavy metals was trace, 15.0, 17.5, 24.0, 25.0, 84.5 and 470.0 ppm, respectively. Thereby, in the order of each element to uptaked by rice seedlings, they were arranged as follow; Zn>Cu>Ni>Pb>Cd>Co>Cr. 5) The hazardous concentrations of root activity by toxic heavy metals in culture solution were Cd; below 0.05, Cu; 0.05-0.5, Cr; below 0.5, Ni; 0.5-1.0, Co; 0.5-1.0, Zn; above 0.5, Pb; 0.5-5.0 and Mn; 1.0-10.0 ppm. The hazardous degree of root activity by toxic heave metals was in the order of Cd>Cu>Cr>Zn>Ni>Co>Pb>Mn.

• Journal of the Korean Magnetics Society
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• v.9 no.6
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• pp.291-295
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• 1999

$NiFe/Co/Al_2O_3/Co/IrMn$ tunneling junctions were grown on (100)Si wafer and their spin-valve tunneling magnetoresistance (TMR) was studied. The tunneling junctions were grown by using a 5-gun RF/DC magnetron sputter. $Al_2O_3$ barrier layer was formed by exposing Al layer to oxygen atmosphere at 6$0^{\circ}C$ for 72 hours. Strong exchange coupling interaction is observed between the ferromagnetic Co and the antiferromagnetic IrMn of Co/IrMn bilayer when IrMn is 100$\AA$ thick. $NiFe(183\;{\AA})/Co(17\;{\AA})/Al_2O_3(16\;{\AA})/Co(100\;{\AA})/IrMn(100\;{\AA})$ tunneling junction shows best TMR ratio of about 10% in the applied magnetic field range of $\pm$20 Oe. The TMR ratio is improved about 23% and electrical resistance is decreased about 34% when annealed at 200 $^{\circ}C$ for 1 hour in magnetic field of 330 Oe, parallel to the bottom electrode. With increasing the active area of junction the TMR ratio increases while electrical resistance decreases.

• Resources Recycling
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• v.4 no.3
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• pp.26-31
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• 1995

The leaching characteristics of manganese nodules were investigated in dilute hydrochloric acid solution using copper malie as a reductant. Thc capper matte has been found to be an effective reductant for exhacting morc than 96% of Mn, 95% of Ni, 91% of Ca, 88% of Cu and 36% of Fe when leached in 2.5 M HCI at 70$^{\circ}$C for 2hr. The dissolutions of Mu, Co, and Ni depend on thc amaunt of added cappcr matte. 7he ratin of liquid and solid is an important [actor on the extraction of metals during leaching The dissolution af Mn, Co, Ni and Cu incrcascd w~th the increase in temperalure of leachant. The leaching rates of Mn, Co, NI and Cu from manganese nodule m the presznce of copper matte is limited by bath thc surface chemical reaction and pare diffusion processes. Thc activation energies far Mn. Co: Ni and Cu were 17. 61, 12.8, 17.2 and 57.88 KcaUmol, rcspcctively.

• Advances in environmental research
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• v.3 no.4
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• pp.321-335
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• 2014

Eight trace metals, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn, were measured in the urban soil of Guwahati City, Assam, India from 31 sites representing five different types of land use, residential, commercial, industrial, public utilities, and roadside. Cd and Co occurred in very low concentrations (Cd << Co) in all types of land use without any significant variation from one type of land use to another. Ni concentrations were more than those of Co, and the concentrations depended on land use pattern. Average Cr and Cu concentrations were ${\geq}100mg/kg$, but Cr had a significantly higher presence in industrial land use. Pb concentrations showed similar trends. The two metals, Mn and Zn, were present in much larger amounts compared to the others with values ${\geq}300mg/kg$. Industrial and roadside soil contained much more Mn while commercial soil was enriched with Zn. Toxicity Characteristic Leaching Procedure (TCLP) was used for elucidating the mobility characteristics of the eight heavy metals. Mn suffered the highest leaching from commercial land (9.9 mg/kg on average) and also from other types of land. Co, Cu and Pb showed higher leachability from commercial soils but the leached concentrations were less than those of Mn. The two metals, Zn and Ni, were leached from residential land in considerable amounts. The TCLP showed Mn to be the most leachable metal and Cr the least.

• Journal of the Korean Electrochemical Society
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• v.16 no.3
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• pp.162-168
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• 2013

$Li_2MnO_3-LiMO_2$(M=Ni, Co, Mn) nano-composite is a promising cathode material for xEV application due to its high theoretic capacity. However high voltage operating system of $Li_2MnO_3-LiMO_2$(M=Ni, Co, Mn) has worked as a hurdle in its application because of the inherent demerits, such as cycle life degradation and gas evolution. In order to enhance cell performance of $Li_2MnO_3-LiMO_2$(M=Ni, Co, Mn)/graphite cell, we examined electrolyte mainly composed of FEC, fluroalkyl ether and $LiPF_6$ (F-based EL). F-based EL showed much better discharging retention ratio than 1.3 M $LiPF_6$ EC/EMC/DMC (3/4/3, v/v/v) (STD). Furthermore gas evolution, especially CO and $CO_2$ during $60^{\circ}C$ storage for 30 days was dramatically reduced owing to thermal stable SEI formation effect of F-based EL.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.2
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• pp.88-92
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• 2003

The correlationship between heat treatment condition and electrical properties of the Mn-Co-Ni oxide NTC thermistor for fuel level sensor was investigated by the X-ray diffractometry, density measurement, and electrical properties measurement such as resistivity, B constant, and thermal dissipation constant. It was shown that the heat treatment of NTC thermistor was responsible for sinterability of Mn-Co-Ni oxide. The highest density of 5.10 g/㎤ was obtained at $1250^{\circ}C$, 2 hours, at which the densification was almost completed. This is also manifested from the microstructural observation. It is found that the electrical resistivity and B constant are increased at the elevated sintering temperatures. The NTC specimens prepared in this study showed the conventional decrease of resistance with the measured temperature and the linear behavior of output voltage with fuel levels. Therefore, the electrical properties of thermistor were closely correlated with sintering condition. and the Mn-Co-Ni oxide thermistor prepared in this study has a great possibility enough to apply for an automobile fuel level sensor.