• Korean Journal of Materials Research
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• v.4 no.6
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• pp.704-709
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• 1994

The $(LaS)_xCrS_2(x \approx 1.20$) of the incommensurate misfit layer was systhesized from reactant mixture of$La_S_3$,Cr and S at 1273K. Powder X-ray diffration of $(LaS)_xCrS_2(x \approx 1.20$) was indexed as a complex structure consisted with a monoclinic LaS-sublattice, a triclinic $CrS_{2}$-sublattice and their superlattice. The temperature dependence of sublattice dimension was investigated by the X-ray diffraction analysis at low temperature. The magnetic susceptibility of $(LaS)_xCrS_2(x \approx 1.20$) was measured between 77K and room temperature using a Faraday balance method. $(LaS)_xCrS_2(x \approx 1.20$) was paramagnetic on a $\sigma$-H plot at room temperature. The observed effective magnetic moment( p dr) was in fair agreement with the value calculated by spin-only contribution for $Cr^{3+}$ and spin and orbital contribution for $La^{3+}$.

• Journal of the Korean Magnetics Society
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• v.25 no.6
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• pp.175-179
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• 2015

The half-metallicity and magnetism of the (001) surfaces of $(AlP)_1/(CrP)_1$ superlattice were investigated by means of FLAPW (Full-potential Liniarized Augmented Plane Wave) method. We considered four types of (001) surface termination, i.e., Al(S)-, Cr(S)-, P(S)Al(S-1)- and P(S)Cr(S-1)-term systems. We found that only Cr(S)-term system maintains the half-metallicity at the surface as only this system has the calculated magnetic moment of integer number of bohr magnetons. The magnetic moment of Cr(S) atom in the system was $3.02{\mu}_B$ which was increased from the bulk value by the effects of band narrowing and increased spin-splitting at the surface. The electronic density of states of the P(S) atom in the P(S)Al(S-1)-term showed very sharp surface states due to the broken $p_z$ bonds at the surface. We found there is still a strong p-d hybridization between the P(S) and Cr(S-1) layers in the P(S)Cr(S-1)-term which causes a considerable increase of magnetic moment of P(S) atom.

• Nano
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• v.13 no.10
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• pp.1850118.1-1850118.17
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• 2018

Nanoparticles of the semiconductor catalyst $Cd_xZn_{1-x}S$ were embedded into the metal organic framework MIL-101(Cr) to obtain $Cd_xZn_{1-x}S@MIL-101$(Cr) nanocomposites. These materials not only possess high surface areas and mesopores but also show good utilization of light energy. The ultraviolet-visible diffuse reflectance patterns of $Cd_xZn_{1-x}S@MIL-101$(Cr) nanocomposites showed that $Cd_{0.8}Zn_{0.2}S@MIL-101$(Cr) possessed good visible light response ability among the synthesized nanocomposites. The photocatalytic performance of the $Cd_xZn_{1-x}S@MIL-101$(Cr) nanocomposites were tested via degradation and mineralization of methylene blue in neutral water solution under light irradiation using a 300W xenon lamp. As a result, using $Cd_{0.8}Zn_{0.2}S@MIL-101$(Cr) as a catalyst, 99.2% of methylene blue was mineralized within 30 min. Due to the synergistic effect of adsorption by the MIL-101(Cr) component and photocatalytic degradation provided by the $Cd_{0.8}Zn_{0.2}S$ component, the $Cd_{0.8}Zn_{0.2}S@MIL-101$(Cr) catalyst displayed superior photocatalytic performance relative to $Cd_{0.8}Zn_{0.2}S$ and MIL-101(Cr). Furthermore, $Cd_{0.8}Zn_{0.2}S@MIL-101$(Cr) possessed excellent stability during photodegradation and exhibited good reusability. The remarkable photocatalytic performance of $Cd_{0.8}Zn_{0.2}S@MIL-101$(Cr) is likely due to the effective transfer of electrons and holes at the heterojunction interfaces.

• Korean Journal of Materials Research
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• v.7 no.10
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• pp.898-907
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• 1997

Fe-22Cr-5AI-X(X=Zr, Y)합금을 1143K, 고온 황화(P$s_{2}$=1.11x$10^{-7}$atm, P$O_{s}$ =3.11x$10^{-20atm}$) 및 황화/산화 (P$s_{2}$=8.31x$10^{-8}$atm, P$O_{s}$ =3.31x$10^{-18atm}$) 환경의 복합가스 분위기에서 1-30시간동안 노출하여 합금표면에 형성된 부식층을 관찰하여 SEM/EDS로 분석하였다. Fe-22Cr-5AI합금은 고온 부식환경에서 부식 생성물의 성장은 포물선법칙을 따르고 주요 성분은 결함이 많고 다공질인 철과 크롬의 황화물[(Fe, Cr)Sx]이므로 고온 내식성이 감소하였다. Zr을 1wt%첨가한 Fe-22Cr-5AI합금의 고온 부식거동은 Y을 1wt%첨가한 합금과 비슷한 거동을 나타내었다. 황화환경에서는 Cr의 선택 황화에 의한 크롬 황화물(CrS)이 생성되고 노출시간의 경과에 따라 (Fe, Cr)Sx나 (Cr, Fe)Sx 등의 황화물의 성장으로 고온 내식성이 감소하였다. 그러나 황화/산화환경에서는 초기에는 알루미늄산화물(A $I_{2}$ $O_{3}$)및 지르코늄산화물(Zr $O_{2}$)등이 생성되어 보호적이었으나 15시간이후 부터 (Fe, Cr)Sx나 (Cr, Fe)Sx 의 황화물의 성장으로 고온 내식성이 감소하였다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.399-403
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• 1999

Biosorption of Pb and Cr to Sargassum sagamianum was evaluated in the various conditions. An adsorption equilibrium was reached in about 15 min. for Pb and Cr. The uptake capacity was 224.5 mg Pb/g biomass and 77.5 mg Cr/g biomass, respectively. The adsorption parameters for Pb and Cr were determined according to Langmuir and Freundlich model. Biosorption of Pb and Cr was increased with an increase in pH value. Pb and Cr adsorbed by S. sagamianum could be recovered by desorption process with 0.1M HCl, 0.1M $HNO_3$ and 0.1M EDTA and the efficiency of Pb desorption was above $90\%$, whereas the efficiency of Cr desorption was below $51\%$.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.2
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• pp.67-75
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• 2002

The human complement receptor type 1 (CR 1, C3 b/C4b receptor) is a polymorphic membrane glycoprotein expressed on human erythrocytes, peripheral leukocytes, plasma and renal glomerular podocytes, which consists of transmembrane and cytoplasmic domains with 30 repeating homologous protein domains known as short consensus repeats (SCR). CR1 has been used as an inhibitor for inflammatory and immune system for the past several years. Recently; it is reported that CRl was found to suppress the hyper-acute rejection in xeno-transplantation and can be used to cure autoimmune diseases. A soluble form of CRl, called sCRl, is a recombinant CRl by cleaving the transmembrane domain at C-terminus and has been expressed in Chinese Hamster Ovary (CHO) cells. Several purification methods for sCR1 from CHO cells have been reported, but most of them require complicated steps at high cost. Moreover, such methods are mostly performed under the pH condition apt to denaturing sCR1 and causes sCRl losing its activity. We here report a rapid and efficient method to purify sCR1 from CHO cell. The new method consists of a two-stage of cell culture by cultivating cells in serum medium followed by serum-free medium, and a two-stage of column purification by means of heparin and gel filtration column chromatography. By using this novel method, sCR1 can be purified in a simple and effective way with high yield and purity, furthermore, the purified sCR1 was confirmed to retain its activity to suppress the complement activation in vivo and ex vivo.

• The Korean Journal of Nuclear Medicine
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• v.19 no.1
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• pp.127-136
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• 1985

To evaluate change of serum $beta_2-microglobulin$ concentration$(s\beta_2-MG)$ and the usefulness of $s\beta_2-MG$ and $s\beta_2-MG/serum$ creatinine concentration(sCr) ratio in various renal diseases, $s\beta_2-MG$ and sCr were measured in 25 normal controls and 90 patients of various renal diseases(16 cases of glomerulonephritis, 12 cases of acute renal failure, 8 cases of chronic renal failure, 24 cases of nephrotic syndrome, 15 cases of tubulointerstitial diseases and 15 cases of lupus nephritis) using $Phadebas^\circledR$ $Beta_2-Micro$ Test kits. The results were as follows; 1) In normal control, the mean value of $s\beta_2-MG$ was $1.65{\pm}0.41mg/l$ and the mean value of $s\beta_2-MG/sCr$ ratio was $0.14{\pm}0.05$. 2) In various renal diseases, the mean value of $s\beta_2-MG$ was $6.74{\pm}5.47mg/l$. The mean value of $s\beta_2-MG/sCr$ ratio was $0.24{\pm}0.11$ and significantly elevated than that of normal control. (p<0.05) 3) The correlation between $s\beta_2-MG$ and sCr in glomerular and tubulointerstitial disease was log $s\beta_2-MG-0.90$ log sCr-0.48 and its correlation coefficient was 0.78(p<0.05). 4) In glomerular disease, the correlation between $s\beta_2-MG$ and sCr was log $s\beta_2-MG-0.89$ log sCr-0.46(r - 0.76) and in tubulointerstitial disease, it was log, $s\beta2-MG-0.95$ log sCr-0.59 (r-0.87). There was no significant difference between the two groups(p<0.05). 5) Among 32 cases of glomerular and tubulointerstitial disease patients, whose sCr was within normal range, 17 cases showed elevated $s\beta_2-MG$. The mean values of $s\beta_2-MG/sCr$ ratio in these patients was $0.30{\pm}0.14$ and significantly elevated than that of normal control(p<0.05). 6) In 15 cases of lupus nephritis, 12 cases showed elevated $s\beta_2-MG$ with normal sCr and 12 cases showed elevated $s\beta_2-MG/sCr$ ratio. With above results, it was found that the $s\beta_2MG$ can be used as an index of glomerular filtration rate as in the case of sCr and that $s\beta_2-MG/sCr$ ratio can be used as a tool in early detection of slightly decreased glomerular filtration rate and in detection of the renal disease of increased $\beta_2-MG$ production.

• Journal of Magnetics
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• v.8 no.4
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• pp.142-145
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• 2003

Valence states and electronic structures of Cr-doped $Nd_{1/2}A_{1/2}Mn_{1-y}Cr_{y}O_3$(NAMO; A=Ca, Sr) manganites have been investigated using x-ray absorption spectroscopy (XAS) and high-resolution photoemission spectroscopy (PES). All the Cr-doped NAMO systems exhibit the clear metallic Fermi edges in the Mn $e_{g}$ PES spectra near $E_{F}$. The spectral intensity at $E_{F}$ is higher for Cr-doped N $d_{l}$ 2/S $r_{l}$ 2/Mn $O_3$(NSMO) than for Cr-doped N $d_{l}$ 2/C $a_{l}$ 2/Mn $O_3$ (NCMO), reflecting the stronger metallic nature for NSMO than for NCMO. The measured Cr 2p XAS spectra are found to be very similar to that of C $r_2$ $O_3$, indicating that Cr ions in Cr-doped NAMO are in the trivalent C states ( $t^3$$_{2g}$). The Cr 2p XAS data are consistent with the Cr 3d PES spectra located at ∼1.3 eV below $E_{F}$ and having no emission near $E_{F}$.

• Journal of the Korean Magnetics Society
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• v.15 no.5
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• pp.257-260
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• 2005

We investigated the half-metallicity and magnetism for the zinc-blende CrS(001) surfaces by use of the full-potential linearized augmented plane wave (FLAPW) method. We considered two-types of (001) surfaces terminated by Cr (Cr-Term) and S (S-Term) atoms, respectively. From the calculated layer-by-layer density of states, it is found that both of the systems retain the half-metallicity at the (001) surfaces. The calculated magnetic moment ($4.07\;{\mu}_B$) for the CrS(S) atom in Cr-Term is enhanced considerably compared to the bulk value ($3.61\;{\mu}_B$) while that ($3.15\;{\mu}_B$) of the Cr(S-1) in S-Term is much reduced.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.86-93
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• 1997

Purpose: To assess the ability of in vivo H-1 MRS to determine the degree of malignancy and to characterize the histopathologic type of intracranial solid tumors. Materials and Methods: In vivo H-1 MR spectra of the pathologically-proven 81 intracranial soild tumors (low-grade glioma 17 cases, high-grade glioma 31 cases, lymphoma 9 cases, meningioma 8 cases, central neurocytoma 4 cases, medulloblastoma 3 cases, PNET 3 cases, metastasis 2 cases, others 4 cases) were analyzed. H-1 MR spectroscopy was performed on a 1.5T MR unit using PRESS sequence with a TR of 2000ms, a TE of 270 or 135ms and a voxel size of $2{\times}2{\times}2cm^3$ for all spectra. N-acetyl aspartate (NAA)/Creatine complex(Cr), Choline complex (Cho)/Cr, and lactate (Lac)/Cr ratios were measured on the peak heights of each resonance and compared among the different tumors. Results: All intracranial solid tumors demonstrated decreased NAA, elevated Cho and lactate, and variable Cr levels. All tumors showed increased Cho/Cr and Lac/Cr, whereas NAA/Cr level was decreased. Mean Cho/Cr and Lac/Cr ratios were significantly higher in high-grade gliomas than in low-grade gliomas. However, NAA/Cr ratio showed no significant difference between low-grade and high-grade gliomas. Very high Cho peaks were seen in lymphomas, meningiomas, medulloblastomas, and neurocytomas in addition to high-grade gliomas. Conclusion: H-1 MRS may be useful in differentiating between low-grade and high-grade gliomas, however cannot characterize the histologic types or subtypes of tumors.