• Economic and Environmental Geology
• /
• v.45 no.5
• /
• pp.477-486
• /
• 2012

High-resolution bathymetry and physico-chemical properties of manganese nodules were explored to identify the relationship between morphological features and nodule occurrences in the KR1, one of the Korean contract nodule fields located in the NE Pacific. The high-resolution seabed mapping showed that the southwestern sector of the KR1 (KR1-1) was relatively deeper than the northeastern sector (KR1-2) which is occupied by small-scale seamounts. In terms of nodule occurrence, manganese nodules in the KR1-1 were comparatively larger (2-4 cm) with rough surface (t-type) and discoidal shapes (D-type), while those in the KR1-2 were generally small (<2 cm) with smooth surface (s-type) and irregular shapes (I-type). In addition, the nodules in the KR1-1 had higher contents of Cu, Mn and Ni. Such connections of water depths to nodule appearances and metal contents are commonly observed in the Pacific nodule fields. On the other hand, the nodules in the KR1-2 tend to be controled by morphological features. The seamounts in the KR1-2 might continuously provide rock fragments as new nuclei of manganese nodules. As a result, the nodules could not grow over than 2 cm and showed the shapes of a newbie (i.e., smooth surface and irregular shapes). As a result, our observations indicate that occurrence features of manganese nodules could be subjected to water depths and seabed morphology simultaneously.

• Resources Recycling
• /
• v.15 no.4 s.72
• /
• pp.3-12
• /
• 2006

The feasibility for the employment of manganese nodule as an adsorbent for $SO_{2}$ gas has been investigated. The specific surface area of manganese nodule particle, which used in the experiments, was ca. $221.5m^{2}/g$ and the content of sulfur in manganese nodule was observed to significantly increase after $SO_{2}$ was adsorbed on it. The EPMA for the distilled water-washed and methanol-washed manganese nodule particle after $SO_{2}$ adsorption showed that its sulfur content was slightly decreased to 14.7% and 13.1% respectively, from 15.4% before washing. The XRD analysis of manganese nodule showed that todorokite and birnessite, which are manganese oxides, and quartz and anorthite were the major mineralogical components and weak $MnSO_{4}$ peaks were detected after $SO_{2}$ was adsorbed on manganese nodule. For an comparative investigation, limestone was also tested as an adsorbent for $SO_{2}$, however, no peaks for $CaSO_{4}$ were found by XRD analysis after the adsorption of $SO_{2}$. As the size of adsorbent increased, time for breakthrough was decreased and the adsorbed amount of $SO_{2}$ was also diminished. The $SO_{2}$ adsorption was hindered when its flow rate became high and the adsorption capacity of manganese nodule was observed to be superior to that of limestone. In addition, the mixture of manganese nodule and limestone did not show an increase in the adsorption of $SO_{2}$. Finally, as the temperature was raised, the adsorbed amount of adsorbate on manganese nodule was found to be decreased.

• Journal of the Korean Chemical Society
• /
• v.50 no.4
• /
• pp.315-320
• /
• 2006

manganese oxides have been prepared by Chimie Douce redox reaction between permanganate and chalcogen element fine powder under acidic condition (pH = 1). According to powder X-ray diffraction analyses, the S- and Se-doped manganese oxides are crystallized with layered birnessite and tunnel-type -MnO2 structures, respectively. On the contrary, Te-doped compound was found to be X-ray amorphous. According to EDS analyses, these compounds contain chalcogen dopants with the ratio of chalcogen/manganese = 4-7%. We have investigated the chemical bonding character of these materials with X-ray absorption spectroscopic (XAS) analysis. Mn K-edge XAS results clearly demonstrated that the manganese ions are stabilized in octahedral symmetry with the mixed oxidation states of +3/+4. On the other hand, according to Se K- and Te L1-edge XAS results, selenium and tellurium elements have the high oxidation states of +6, which is surely due to the oxidation of neutral chalcogen element by the strong oxidant permanganate ion. Taking into account their crystal structures and Mn oxidation states, the obtained manganese oxides are expected to be applicable as electrode materials for lithium secondary batteries.

• Journal of the Korean Ceramic Society
• /
• v.15 no.2
• /
• pp.89-97
• /
• 1978

The basic mechanism of adherence in sintered high purity alumina ceramic-to-metal bonding was studied. Emphasis was placed on flux composition, porosity of the fired ceramics, and metallizing mixtures. The study was conducted on 95 and 99.5% alumina, using molydbenum-manganese, molybdenum-manganese-silicon dioxide metallizing compositions. Metallizing was performed in wet hydrogen (dew point, ＋17$^{\circ}C$) at 145$0^{\circ}C$ for 45min. This experiment indicated that adhernece mechanism of ultra high purity alumina ceramic was attributed to formation of $MnAl_2O_$4, and in the case of 95% alumina containing glass, the migration of glass from the interface into the void of the metal coating was the main role to the adhrence. It showed also that greater the bond-strength was resulted as porosity was increased.

• Journal of Plant Biology
• /
• v.10 no.3_4
• /
• pp.4-9
• /
• 1967

The aim of present study is to elucidate the effects of manganese and aluminium ions on the germination and seedling growth of Pinus banksiana and Alnus tinctoria and to estimate the limiting level of those ions in the cultivated soils. The rate of germination of Pinus banksiana was increased under the relatively low concentration of Mn and Al (100 p.p.m), however, the germinating activity was not affected. High concentration over 110 p.p.m. of Mn and Al was related to the reduced percentage of germination and seedling growth of Pinus banksiana and Alnus tinctoria. Soils sampled from various parts of Korea contained Mn as much as high level that would be harmful for the seedling growth of Pinus banksiana and Alnus tinctoria.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.6 no.1
• /
• pp.38-44
• /
• 2015

In this paper, a finite element dynamic simulation study was performed to gain an insight about the blast wall test details for the offshore structures. The simulation was verified using qualitative and quantitative comparisons for different materials. Based on in-depth examination of blast simulation recordings, dynamic behaviors occurred in the blast wall against the explosion are determined. Subsequent simulation results present that the blast wall made of high energy absorbing high manganese steel performs much better in the shock absorption. In this paper, the existing finite element shock analysis using the LS-DYNA program is further extended to study the blast wave response of the corrugated blast wall made of the high manganese steel considering strain rate effects. The numerical results for various parameters are verified by comparing different material models with dynamic effects occurred in the blast wall from the explosive simulation.

• Journal of Welding and Joining
• /
• v.34 no.5
• /
• pp.77-82
• /
• 2016

In this study, Microstructure and hardness of 1st layer with crystallographic orientation were investigated about solidification structure in multipass weld using high Mn-Ni flux cored wire. Microstructure of solidification consisted of austenite matrix and a little ${\varepsilon}-phase$ in grain boundaries. Orientation of grains was usually (001), (101), (111). According to crystallographic orientation, morphology of primary dendrite was different. The depletion of Fe and the segregation of Mn, C, Ni, Si, Cu, Cr, O were found along the grain boundaries. The area of segregation was wide with an order of (001), (101), (111) grains. And hardness of grains with crystallographic orientation increased with an order of (001), (101), (111) grains because of the segregation along dendrite boundary.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1996.05a
• /
• pp.93-93
• /
• 1996

• Journal of Ocean Engineering and Technology
• /
• v.26 no.3
• /
• pp.55-60
• /
• 2012

This study was carried out to investigate the effect of the deformation temperature in high manganese austenitic stainless steel. ${\alpha}$'-martensite was formed with a specific direction by deformation. The volume fraction of the deformation induced martensite was increased by increasing the degree of deformation and decreasing the deformation temperature. With the increase in the deformation, the hardness and tensile strength were increased, while the elongation was rapidly decreased at the initial stage of the deformation, and then gradually decreased. The hardness and tensile strength were increased and the elongation was decreased with adecrease in the deformation temperature. The hardness and tensile strength were strongly controlled by the volume fraction of martensite, but the elongation was controlled by the transformation behavior of the deformation induced martensite.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.7
• /
• pp.3015-3023
• /
• 2012

The mitochondrial antioxidant protein manganese superoxide dismutase (MnSOD) may represent a new type of tumor suppressor protein. Overexpression of the cDNA of this gene by plasmid or recombinant lentiviral transfection in various types of cancer leads to growth suppression both in vitro and in vivo. We previously determined that changes in MnSOD expression had bidirectional effects on adriamycin (ADR) when combined with nitric oxide (NO). Radiation induces free radicals in a manner similar to ADR, so we speculated that MnSOD combined with NO would also have a bidirectional effect on cellular radiosensitivity. To examine this hypothesis, TE-1 human esophageal squamous carcinoma cells were stably transfected using lipofectamine with a pLenti6-DEST plasmid containing human MnSOD cDNA at moderate to high overexpression levels or with no MnSOD insert. Blastidicin-resistant colonies were isolated, grown, and maintained in culture. We found that moderate overexpression of MnSOD decreased growth rates, plating efficiency, and increased apoptosis. However, high overexpression increased growth rates, plating efficiency, and decreased apoptosis. When combined with NO, moderate overexpression of MnSOD increased the radiosensitivity of esophageal cancer cells, whereas high MnSOD overexpression had the opposite effect. This finding suggests a potential new method to kill certain radioresistant tumors and to provide radioresistance to normal cells.