• Corrosion Science and Technology
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• v.7 no.6
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• pp.315-318
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• 2008

The atmospheric corrosion performance of Al-alloying, Si-alloying and Al-Si-alloying steel were studied by wet/dry cyclic corrosion tests (CCT) at $30^{\circ}C$ and 60% relative humidity (RH). The corrosion electrolyte used for CCT was 0.052 wt% $NaHSO_{3}$ (pH~4) solution. The result of gravimetry demonstrated that Al-Si-bearing steels showed lower corrosion resistance than other rusted steels. But the rusted 0.7%Si-alloying steel showed a better corrosion resistance than rusted mild steel. Polarization curves demonstrated that Al-/Si-alloying and Al-Si-alloying improved the rest potential of steel at the initial stage; and accelerated the cathodic reduction and anodic dissolution after a rust layer formed on the surfaces of steels. XRD results showed that Al-Si-alloying decreased the volume fraction of $Fe_{3}O_{4}$ and $\alpha-FeOOH$. The recycle of acid accelerated the corrosion of steel at the initial stage. After the rust layer formed on the steel, the leak of rust destabilized the rust layer due to the dissolution of compound containing Al (such as $FeAl_{2}O_{4}$, $(Fe,\;Si)_{2}(Fe,\;Al)O_{4}$). Al-Si-alloying is hence not suitable for improving the anti-corrosion resistance of steel in industrial atmosphere.

• 보존과학연구
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• s.16
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• pp.59-111
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• 1995

Chemical composion and crystal form of Corrosion products found on archaeological iron objects were analyzed using X-ray fluorescence analysis, micro-X-ray powder diffraction analysis and ion chromatographic technique. The nature and behavior of the corrosion products were studied in order to aid in the conservation and restoration of burial iron objects. Twenty-two samples analyzed in this study were collected from iron object found in Korea and Japan. The corrosion products of iron objects from burial mounds contain $\alpha$-FeOOH, $\beta$-FeOOH, $\gamma$-FeOOH, $Fe_3O_4$and amorphous iron hydroxides. The content of $\alpha$-HeOOH is the greatest. Because, Ageing for long period should change the amorphous iron hydroxides is considerably less than that in usual atmospheric corrosion products. The concentration of chlorine and sulfine is remarkably variable ($Cl^-$ : 100- 30,000ppm, $SO_4^-2$ : 20-10,000ppm),but the reasons are unclear. The presence of generally high concentrations of chlorine and sulfine the corrosion products of iron objects seem to be influenced by the marine climatic condition. The presence of high chlorine and sulfine concentrations in the corrosion products of iron objects seem to be influenced by the marine burial environments.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.641-644
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• 1995

We have studied the effect of the nitrogen on the microstructure, thermomagnetic properties and corrosion resistance of Fe-Hf-C-N nanocrystalline thin films with high permeability and high saturation magnetization. These films were fabricated by reactive sputtering in $Ar+N_{2}$ plasma using an rf magnetron sputtering apparatus. As $P_{N2}$ increases, the microstructure changes from amorphous to crystalline $\alpha$-Fe phase and again returns to amorphous one. Spin wave stiffness constant increases with $P_{N2}$ until 5% $P_{N2}$, and then decreases with the further increase. This trend corresponds well with that of the microstructure with increasing $P_{N2}$. The Fe-Hf-C-N films with over 3% $P_{N2}$ show higher corrosion resistance than the N-free Fe-Hf-C films. The Fe-Hf-C-N films are considered to have high potentials for the head core materials suitable for high density recording systems, owing to their excellent soft magnetic properties and corrosion resistance.

• Journal of Powder Materials
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• v.16 no.5
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• pp.336-341
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• 2009

To produce alloy powders with only Sm$_2$Fe$_{17}$ single phase by reduction-diffusion (R-D) method, the effect of excess samarium oxide on the preparation of Sm-Fe alloy powder during R-D heat treatment was studied. The quantity of samarium oxide was varied from 5% to 50% whereas iron and calcium were taken 0% and 200% in excess of chemical equivalent, respectively. The pellet type mixture of samarium, iron powders and calcium granulars was subjected to heat treatment at 1100$^{\circ}C$ for 5 hours. The R-D treated pellet was moved into deionized water and agitated to separate Sm-Fe alloy powders. After washing them in deionized water several times, the powders were washed with acetic acid to remove the undesired reaction products such as CaO. By these washing and acid cleaning treatment, only 0.03 wt% calcium remained in Sm-Fe alloy powders. It was also confirmed that the content of unreacted $\alpha$-Fe in Sm$_2$Fe$_{17}$ matrix gradually decreased as the percentage of samarium oxide is increased. However, there was no significant change above 40% excess samarium oxide.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.3
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• pp.158-162
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• 2000

The high temperature oxidation behavior and the surface defect in Fe-25Mn-1.5A1-0.5C steel was investigated by XRD (X-ray Diffractin) and electron microscopy. The intra- and inter-granular oxides were formed by the selective oxidation of manganese and aluminum, which were identified to MnAl2O4 phase. Aluminum nitride (AlN) was formed in front of these oxides. The ${\gamma}$-matrix was transformed to ${\alpha}$- and ${\varepsilon}$- phases by the selective oxidation of manganese. The surface defect, micro-scab was induced by the difference of the high temperature ductility between the matrix and the inter-granular oxide.

• Journal of Microbiology and Biotechnology
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• v.21 no.10
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• pp.1057-1063
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• 2011

Herein, a novel ginsenosidase, named ginsenosidase type IV, hydrolyzing 6-O-multi-glycosides of protopanaxatriol-type ginsenosides (PPT), such as Re, R1, Rf, and Rg2, was isolated from the Aspergillus sp. 39g strain, purified, and characterized. Ginsenosidase type IV was able to hydrolyze the 6-O-${\alpha}$-L-($1{\rightarrow}2$)-rhamnoside of Re and the 6-O-${\beta}$-D-($1{\rightarrow}2$)-xyloside of R1 into ginsenoside Rg1. Subsequently, it could hydrolyze the 6-O-${\beta}$-D-glucoside of Rg1 into F1. Similarly, it was able to hydrolyze the 6-O-$_{\alpha}$-L-($1{\rightarrow}2$)-rhamnoside of Rg2 and the 6-O-${\beta}$-D-($1{\rightarrow}2$)-glucoside of Rf into Rh1, and then further hydrolyze Rh1 into its aglycone. However, ginsenosidase type IV could not hydrolyze the 3-O- or 20-O-glycosides of protopanaxadiol-type ginsenosides (PPD), such as Rb1, Rb2, Rb3, Rc, and Rd. These exhibited properties are significantly different from those of glycosidases described in Enzyme Nomenclature by the NC-IUBMB. The optimal temperature and pH for ginsenosidase type IV were $40^{\circ}C$ and 6.0, respectively. The activity of ginsenosidase type IV was slightly improved by the $Mg^{2+}$ ion, and inhibited by $Cu^{2+}$ and $Fe^{2+}$ ions. The molecular mass of the enzyme, based on SDS-PAGE, was noted as being approximately 56 kDa.

• Journal of Conservation Science
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• v.6 no.1 s.7
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• pp.15-30
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• 1997

The chamical and physical properties of the fragments of an ancient pottery such as earthenware, gliazed pottery and celadon excavated in Chonnam province has been investigated by X-ray diffraction inductively coupled plasma spectroscopy(ICP), thermal mechanical analysis(TMA). Glazed pottery fragments of Chonnam province are cotaining Fe2O3 $4\~7\%$ by the analyis of ICP, firing temperature range was presumed to $1100-1150^{\circ}C$ by TMA. Celadon fragments of Chonnam province are containing Fe2O3 $2\~3\%$ by the analyis of ICP, firing temperature range was presumed to $1140\~1200^{\circ}C$ by TMA. The charateristics in the trace element composition of an ancient pottery of Chonnam provinceis are similar, it is an reflection of similar geological charateristics. The charateristic elements of Chonnam provincical ancient pottery were Rb, Sr, V, Zr, Y, Nd, Sc, La, Ce, Nb, Sm, Eu, Dy and Yb of the analyzed 21 trace elements. By Fe2O3-Zn ditribution diagram, potteries excavated in Yong-am, celadons excavated in Haenam, Kangjin, Buan and glazed pottery excavated in Hae-nam are grouped into the same class.

• Journal of Applied Biological Chemistry
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• v.56 no.3
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• pp.141-146
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• 2013

Constituents of the essential oil (EO)s and hydrosol of rosemary (Rosmarinus officinalis L.) and lavender (Lavandula angustifolia Mill.) were analyzed by gas chromatography-mass spectrometry (GC-MS). The identified major constituents were ${\alpha}$-pinene (40.96%), camphor (34.44%), verbenone (45.31%), and camphor (67.04%) in rosemary EO, lavender EO, rosemary hydrosol, and lavender hydrosol, respectively. The antioxidant activity of EO and hydrosol extracted from rosemary and lavender were evaluated. Both EO showed di(phenyl)-(2,4,6-trinitrophenyl) iminoazanium (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) free radical scavenging activities as well as $Fe^{2+}$ ion chelating activity but no alkyl radical scavenging activity. Rosemary EO showed higher DPPH radical scavenging activity than lavender, whereas lavender EO showed higher $Fe^{2+}$ ion chelating activity. Both rosemary and lavender hydrosols showed alkyl radical scavenging activity, but only lavender hydrosol showed an activity on $Fe^{2+}$ chelating assay. Both rosemary and lavender hydrosols also protected the dermal fibroblast and the HaCaT keratinocytes against $H_2O_2$-induced cytotoxicity.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.5
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• pp.312-320
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• 2013

Particulates in drinking water distribution system (DWDS) are mostly influenced by internal corrosion of metal pipes and sediment in pipelines due to the solution of this effect is limited. The particle size, component and properties of compounds for particulates in distributed water are different and the difference of these characteristics will be occurred by the kind of facilities, pipe condition, external factors and supply system etc. In this study, conducting the investigation of water quality in DWDS researches with particulates in the water. Monitoring sites were each water supply reservoir and the end of water supply area in DWDS. To collect particulate material at each sampling site, $47{\phi}$ glass microfiber filter type GF/C was performed using a filtration. Substances that the effect of the turbidity in the water according to particulate suspended solids and inorganic materials is due to the increasing particulates in the end of DWDS were increased. The result of compounds analysis by using X-ray diffraction (XRD) were Goethite (${\alpha}$-FeOOH), Magnetite ($Fe_3O_4$) in the end of DWDS and Quartz ($SiO_2$), Yeelimite ($Ca_4Al_6O_{12}SO_4$) at the effluent of waterworks and reservoirs. There were differences the compounds and sediments in the releasing or remaining water distribution facilities.

• Natural Product Sciences
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• v.20 no.3
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• pp.160-169
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• 2014

44 compounds and 9 minerals were isolated from and detected in the New Zealand deer velvet antler Cervus elaphus var. scoticus L$\ddot{o}$nnberg. The chemical structures of (1 - 26) were identified on the basis of the spectroscopic methods and comparisons with literature, respectively. The structures were identified as cholesterol (CS, 6), 7-keto-CS (7), $7{\beta}$-hydroxy-CS (8), and $7{\alpha}$-hydroxy-CS (9), and included 12 steroid $3{\beta}$-O-(palmitic/stearic/myristic acid esters; PM/SA/MS) [CS-$3{\beta}$-O-PM (1 - 1), CS-$3{\beta}$-O-SA (1 - 2), CS-$3{\beta}$-O-MR (1 - 3), 7-keto-CS-$3{\beta}$-O-PM (2 - 1), 7-keto-CS-$3{\beta}$-O-SA (2 - 2), 7-keto-CS-$3{\beta}$-O-MR (2 - 3), $7{\beta}$-hydroxy-CS-$3{\beta}$-O-SA (3 -1), $7{\beta}$-hydroxy-CS-$3{\beta}$-O-PM (3 - 2), $7{\beta}$-hydroxy-CS-$3{\beta}$-O-MR (3 - 3), $7{\alpha}$-hydroxy-CS-$3{\beta}$-O-SA (4 - 1), $7{\alpha}$-hydroxy-CS-$3{\beta}$-O-PM (4 - 2), and $7{\alpha}$-hydroxy-CS-$3{\beta}$-O-MR (4 - 3)], dinonyl phthalate (5), 8 nucleic acids analogues [uracil (10), deoxyguanosine (11), deoxyuridine (12), uridine (13), deoxyadenosine (14), adenosine (15), inosine (16), and guanosine (17)], and the 9 free amino acids [L-phenylalanine (18), L-isoleucine (19), L-leucine (20), L-tyrosine (21), L-valine (22), L-proline (23), L-threonine (24), L-alanine (25), and L-hydroxyproline (26)]. Also, there are 8 kinds of amino acids [asparagine, serine, glutamine, glycine, histidine, arginine, methionine, and lysine], 2 sialic acids [N-acetylneuraminic acid (27), ketodeoxynonulosonic acid (28)], and 9 minerals [Na > K > Ca > Mg > Fe > Zn > B > Al > Cu] were detected from the autoaminoacid analyzer and ICP spectrometer, HPAEC-PAD/HPLC-FLD, respectively. 9 kinds of oxycholesterol-$3{\beta}$-O-fatty acid ester (2 - 1, 2 - 2, 2 - 3, 3 - 1, 3 - 2, 3 - 3, 4 - 1, 4 - 2, and 4 - 3) and 3 nucleic acids (12, 14, and 15) were isolated from the velvet antler for the first time. 6 kinds of steroids (7, 8, 9, 2 - 1, 3 - 1, and 4 - 1) were examined for their anti-proliferative effects against L1210, P388D1, K562, MEG-01, KG-1, MOLT-4, A549, HepG2, MCF-7, SK-OV-3, and SW-620 cancer cell lines. They showed anti-proliferative effects with $IC_{50}$ values of 0.06, 2.16, 2.42, > 50.0, 1.66 and $8.31{\mu}M$ against L1210, while the values were 24.05, 9.44, 5.22, 0.25. 9.48 and $49.77{\mu}M$ against P388D1, respectively. The others were inactive.