• Journal of the Korean Ceramic Society
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• v.32 no.3
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• pp.394-402
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• 1995

Electrical conductivity and thermoelectric power of the ferrous ferrite system of (Mg0.29-yMnyFe0.71)3-$\delta$O4 have been measured as function of the thermodynamic variables, cationic composition(y), temperature(T) and oxygen partial pressure(Po2) under thermodynamic equilibrium conditions at elevated temperatures. On the basis of the electrical properties-phase stability correlation, the stability regions of the ferrite spinel and its neighboring phases have been subsequently located in the log Po2 vs. y and log Po2 vs. 1/T planes in the ranges of 0 y 0.29, 1100 T/$^{\circ}C$ 1400 and 10-14 Po2/atm 1. The stability region, Δlog Po2(y, 1/T), of the ferrite spinel single phase widens with increasing Mn-content(y) and the boundaries of each region are linear against 1/T with negative slopes.

• Journal of the Korean Ceramic Society
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• v.22 no.6
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• pp.58-70
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• 1985

The bond strength of metal to ceramic sealing in Mo-Mn metallizing was investigated by examining the effects of flux composition in alumina ceramics particle size of molybdenum metal powder wet hydrogen atmosphere and temperature in metallizing. The maximum bond strength was obtained when the glass phase filled almost all the microstructural cavities around the interfacial area with few micropores. Such a favorable microstrcutre waas formed and maximum bond strength was observed between 130$0^{\circ}C$. Also the metal to ceramic bond strength was increased using finer molybdenum metal powder than coarse powder. When content of $SiO_2$ in the flux of alumina ceramics was constant metal to ceramic bond strength was improved with increasing the ratio of CaO to MgO in the flux.

• Journal of the Korean Ceramic Society
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• v.25 no.4
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• pp.321-328
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• 1988

The sintering phenomena, electrical resistivity, dielectric and piezoelectric properties of lead titanate ceramics modified by the partial substitution of La for Pb and Mn for Ti, (Pb1-1.5xLax)(Ti1-yMny)O3 ceramics, have been investigated. In (Pb1-1.5xLax)(Ti1-yMny)O3 system, with increasing lanthanum content, the realtive bulk density increased, but the Curie point and tetragonality (c/a) decreased. The tetragonal-to-cubic phase transition boundary existed in the range of 0.20

• Korean Journal of Pharmacognosy
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• v.22 no.1
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• pp.33-35
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• 1991

Heavy metals may cause trouble(s) in human body. For consideration of the safety of crude drugs cultivated in Korea, we selected some medicinal plants and soils from cultivated site and estimated their heavy metal contents by inductively coupled argon plasma spectrometry (ICAP). Among heavy metals tested, the highest level of Cu and Zn were shown in plants cultivated in Kyung Ki; the highest level of Fe in those in Youngnam and the highest level of Mg and Mn in those in Youngdong. The heavy metal content s were as low as to be permeasible at least for the medicinal plants we selected. There were no significant correlations between heavy metal contents of soils and cultivated medicinal plants.

• Journal of Electrical Engineering and Technology
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• v.2 no.4
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• pp.525-531
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• 2007

Ni(75 wt.%)-Cr(20 wt.%)-Al(3 wt.%)-Mn(4 wt.%)-Si(1 wt.%) alloy thin films were prepared using the DC magnetron sputtering process by varying the sputtering conditions such as power, pressure, substrate temperature, and post-deposition annealing temperature in order to fabricate a precision thin film resistor. For all the thin film resistors, sheet resistance, temperature coefficient of resistance (TCR), and crystallinity were analyzed and the effects of sputtering conditions on their properties were also investigated. The oxygen content and TCR of Ni-Cr-Al-Mn-Si resistors were decreased by increasing the sputtering pressure. Their sheet resistance, TCR, and crystallinity were enhanced by elevating the substrate temperature. In addition, the annealing of the resistor thin films in air at a temperature higher than $300^{\circ}C$ lead to a remarkable rise in their sheet resistance and TCR. This may be attributed to the improved formation of NiO layer on the surface of the resistor thin film at an elevated temperature.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.5
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• pp.455-464
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• 1998

Removal teals of Soxmox were performed using low density ceramic filters doped with various catalysts. Disc type (50 mmO.Dx10 mmt) low density ceramic filters were doped with three different catalysts such as Cu to remove SOx and NOx, and Mn and Co to remove NOx. The air permeabilities and specific surface areas were 40~50cc/min.cm2.cmH2O and 4.1~8.88 m2/g, respectively. Also, the peak pore sizes of catalyst support were 3~5nm. Tests were focused to search optimum operating temperatures for different catalysts. It was found that as the CuO content increases, SOx removal efficiency was increased. NOx removal efficiencies for Mn, Cu and Co, were 85% at 30$0^{\circ}C$, 90% at 40$0^{\circ}C$ and 90% at 45$0^{\circ}C$, respectively.

• 보존과학연구
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• s.6
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• pp.121-196
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• 1985

Atomic absorption spectrophotometer was used for analyzing each 10elements(Cu, Pb, Sn, Zn, Sb, Fe, Ni, Ag, Co and Mn)on 64 Chinese coinsre covered from Shinan seabed sunken ship. The results show that Cu, Pb and Sn were found to be a major elements consisting of coins and its composition ratio was 6 to 2 to 1.The composition of trace elements on coins was classified 3 levels : Sb, Fe and Zn(0.02%-2.2%), Ag, Ni, and Co(50 ppm-5500 ppm) and Mn(Trace). Theam ount of major elements, Cu and Sn were decreased while increased in Pbby the passage of ages (10th - 13th century) in China. There seems to be no systematic compositional change in major elements but content in trace elements was confirmed to increase with age.

• Journal of Forest and Environmental Science
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• v.32 no.1
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• pp.20-26
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• 2016

DTPA (Diethelene-triamine pentaacetic acid) extractable micronutrients of surface soil samples from six different locations of Cox's Bazar and Chittagong districts were studied. All the soils under study were sufficient in DTPA extractable Fe, Mn and Cu contents. The available Zn contents in soils of Dulhazara, Chengchhari and Faissakhali under study were also above the critical limit while soils at Fulchhari, Hasnabad and CU were deficient in available Zn. The study also showed that DTPA extractable Fe content had the significant and positive relationships with clay and soil organic carbon. On the hand, negative and significant relationship was observed between extractable Mn and soil pH while DTPA extractable Zn and Cu were positively and significantly correlated with soil organic carbon of the studied area.

• Journal of the Mineralogical Society of Korea
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• v.1 no.1
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• pp.63-69
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• 1988

Chondrodite form the Wondong mine, Korea, which is the first occurrence from the southern Korea, has been studied for its mineralogical characterization. It occurs in close association with penninite, phlogopite, diopside and garnet within the magnetite ore bodies, which are debeloped along the contact of the Hwajeol Formation and rhyolite. Two kinds of chondrodites are recognized by their different optical properties; the high birefringent untwinned one and the low birefringent twinned one. The former has slightly higher Mn content than the latter. Twinning in chondrodite has been formed in close relation to substitution Mg (Fe, Mn) in the humite solid solution, as evidenced by the chemical variation across the twin lamallae.

• Journal of the Korean Ceramic Society
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• v.25 no.1
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• pp.42-48
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• 1988

Commercially available PTCR (Postive Temperature Coefficient of Resistivity) ceramics which have low room temperature resistance, high PTC effect and temperature coefficient were prepared by La3+ doped semiconducting barium calcium titanate soild solutions. PTCR characteristics were remarkably improved by addition of AST (1/3 Al2O3$.$3/4SiO2$.$1/4TiO2) and MnCl2. That can be explained by formation of liquid phase during sintering and acceptor level on the intergranular layer. Resistivity anormaly increased with decreasing cooling rate. Optimum manufacturing conditions were cooling rate below 100$.$C/hr, Ca and Mn content of 4 mol% &, 0.09-0.12mol% respectively.