• Title/Summary/Keyword: 치환원소

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Magnetostriction of B2-structured FeX (X = Al, Si, Ni, Ga, Ge, and Sn) Alloys: A First-principles Study (B2 구조 FeX(X = Al, Si, Ni, Ga, Ge, Sn) 합금의 자기변형에 대한 제일원리계산)

  • Lee, Sunchul;Odkhuu, Dorj;Kwon, Oryong;Hong, Soon Cheol
    • Journal of the Korean Magnetics Society
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    • v.23 no.4
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    • pp.117-121
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    • 2013
  • In this study we investigated magnetism and magnetostriction of B2-structured FeX (X = Al, Si, Ni, Ga, Ge, and Sn) using a first-principles method, in order to survey the possibility of developing a transition metal based magnetostriction material. The Full-potential Linearized Augmented Plane Wave method was employed for solving the Kohn-Sham equation within the generalized gradient approximation for exchange-correlation interaction between electrons. FeX alloys are stabilized in ferromagnetic states except for the FeSi and FeGe alloys. Magnetostrcition coefficients of FeX (X = Al, Ni, Ga, and Sn) were calculated to be -5, +6, -84, -522ppm, respectively. It is noteworthy that the magnetostriction coefficient (-522ppm) of FeSn is larger than that (+400ppm) of Gafenol.

Preparation and Gas Characterization of Poly(phenylene oxide) Containing Imidazolium (이미다졸륨을 포함하는 폴리페닐렌옥사이드 고분자 제조 및 기체 특성평가)

  • Son, Tae Yang;Jo, Jin Woo;Kim, Ji Hyeon;Kim, Tae Hyun;Tocci, Elena;Nam, Sang Yong
    • Membrane Journal
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    • v.27 no.6
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    • pp.528-535
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    • 2017
  • In this study, halogen element was introduced into polyphenylene oxide polymer using bromination reaction, and then halogen element was replaced with imidazolium. Imidazolium corporated polyphenylene oxide polymer was synthesized and the synthesis was confirmed by various instrumental characterization. In addition, gas permeation properties of $O_2$, $N_2$, $CO_2$ were studied with different imidazolium contents. As the content of imidazolium increased, the ion exchange capacity increased and the mechanical strength decreased. The gas permeance showed a tendency to decrease slightly with increaing imidazolium contents. Whereas, it was confirmed that the tendency of $CO_2/N_2$ ideal selectivity increased as the imidazolium contents increased.

A Comparative Study on the Efficient Reordering Methods of Sparse Matrix Problem for Large-scale Surveying Network Adjustment (대규모 측지망 조정을 위한 희소 행렬의 효율적인 재배열 방법에 대한 비교 연구)

  • Woo, Sun-Kyu;Yun, Kong-Hyun;Heo, Joon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.26 no.1
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    • pp.85-91
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    • 2008
  • When a large sparse matrix is calculated for a horizontal geodetic network adjustment, it needs to go through the process of matrix reordering for the efficiency of time and space. In this study, several reordering methods for sparse matrix were tested, using Sparse Matrix Manipulation System(SMMS) program, total processing time and Fill-in number produced in factorization process were measured and compared. As a result, Minimum Degree(MD) and Mutiple Minimum Degree(MMD), which are based on Minimum Degree are better than Gibbs-Poole-Stockmeyer(GPS) and Reverse Cuthill-Mckee(RCM), which are based on Minimum Bandwidth. However, the method of the best efficiency can be changed dependent on distribution of non-zero elements in a matrix. This finding could be applied to heighten the efficiency of time and storage space for national datum readjustment and other large geodetic network adjustment.

Phase Equilibria of the System Pd-Sb-Te and Its Geological Implications (팔라듐-안티몬-테루르 계(系)의 상평형(相平衡)과 지질학적(地質學的) 의의(意義))

  • Kim, Won-Sa;Chao, George Y.
    • Economic and Environmental Geology
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    • v.26 no.3
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    • pp.327-335
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    • 1993
  • Phase relations in the system Pd-Sb-Te were investigated at $1000^{\circ}$, $800^{\circ}$, and $600^{\circ}C$, using the sealed-capsule technique; the quenched products were studied by reflected light microscopy, X-ray diffraction, and electron microprobe analysis. At $1000^{\circ}C$, the solid phases Pd, $Pd_{20}Sb_7$, $Pd_8Sb_3$, $Pd_{31}Sb_{12}$, and $Pd_5Sb_2$ are stable with a liquid phase that occupies most of the isothermal diagram. Additional solid phases at $800^{\circ}C$ are $Pd_5Sb_3$, PdSb, $Pd_8Te_3$, $Pd_7Te_3$, and a continuous $Pd_{20}Te_7-Pd_{20}Sb_7$ solid solution becomes stable. At $600^{\circ}$, $PdSb_2$, $Pd_{17}Te_4$, $Pd_9Te_4$, PdTe, $PdTe_2$, $Sb_2Te_3$, and Sb and continuous PdSb-PdTe and $PdTe-PdTe_2$ solid solutions are stable. All the solid phases exhibit solid solution, mainly by substitution between Sb and Te to an extent that varies with temperature of formation. The maximum substitution (at.%) of Te for Sb in the Pd-Sb phases is: 44.3 in $Pd_8Sb_3$, 52.0 in $Pd_{31}Sb_{12}$, 46.2 in $Pd_5Sb_2$ at $800^{\circ}C$; 15.3 in $Pd_5Sb_3$, 68.3 in $PdSb_2$ at $600^{\circ}C$. The maximum substitution (at.%) of Sb for Te in the Pd-Te phases is 34.5 in $Pd_5Sb_3$ at $800^{\circ}C$, and 41.6 in $Pd_7Te_3$, 5.2 in $Pd_{17}T_4$, 12.4 in $Pd_9Te_4$, and 19.1 in $PdTe_2$ at $600^{\circ}C$. Physical properties and X-ray data of the synthetic $Pd_9Te_4$, PdTe, $PdTe_2$, $Pd_8Sb_3$, PdSb, and $Sb_2Te_3$ correspond very well with those of telluropalladinite, kotulskite, merenskyite, mertieite II, sudburyite, and tellurantimony, respectively. Because X-ray powder diffraction data consistently reveal a 310 peak ($2.035{\AA}$), the $PdSb_2$ phase is most probably of cubic structure with space group $P2_13$. The X-ray powder pattern of a phase with PdSbTe composition, synthesized at $600^{\circ}C$, compares well with that of testibipalladite. Therefore, testibiopalladite may be a member of the $PdSb_2-Pd(Sb_{0.32}Te_{0.68})$ solid solution series which is cubic and $P2_13$ in symmetry. Thus the ideal fonnula for testibiopalladite, presently PdSbTe, must be revised to PdTe(Sb, Te). Borovskite($pd_3SbTe_4$) has not been found in the synthetic system in the temperature range $1000^{\circ}-600^{\circ}C$.

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Influence of Natural Salt Treatments on Soil Chemical Properties and Inorganic Contents of Garlic (천일염 살포가 토양 화학성과 마늘(Allium sativum L.)의 무기성분 함량에 미치는 영향)

  • Kim, Myung-Sook;Kim, Yoo-Hak;Kang, Seong-Soo;Yun, Hong-Bae;Gong, Hyo-Young;Lee, Sang-Beom
    • Korean Journal of Organic Agriculture
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    • v.20 no.2
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    • pp.231-241
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    • 2012
  • Farming using natural salts for supply of nutrients to crops is increasing recently. It is necessary to evaluate the salt accumulation in soil and the effects on crop growth by treatment of natural salt. This study was conducted at the organic cultivation fields which garlics were planted. The treatments were no natural salts (control) and plots applied 100~600 $kg\;ha^{-1}$ with natural salts. Soil samples were taken from the 0 to 25 cm depth at 12 and 107 day (harvest time) after natural salts application. The results showed that electrical conductivity (EC), exchangeable Na (Exch.$-Na^+$) and Cl- were increased by application of natural salts. But, pH and exchangeable cations ($K^+$, $Ca^{2+}$ and $Mg^{2+}$) had not significantly differences among treatments. In 300 $kg\;ha^{-1}$ plots of natural salt, the level of EC, Exch.$-Na^+$ and $Cl^-$ in top soil (0-5 cm) was were increased more 0.3, 3.7, and 12.7 times than control plot, respectively. EC, Exch.$-Na^+$, and $Cl^-$ were highest in the top 5 cm of soil and decreased with depth at 12 days after natural salts application, but were decreased in the plower layer (0-15cm) at the harvest time because they were leached with natural rain. An increasing the application level of natural salt resulted in increasing of sodium adsorption ratio, exchangeable sodium percentage, and percentage of soil dispersion. The concentration of nutrient uptake such as total nitrogen (T-N), chloride (Cl) in garlic had significant difference between control and plots applied with natural salts The content of T-N of garlic in plots with natural salt application was lower than control plot, but Cl is higher than control plot.

The Study on the Additives and Magnetic Property of YIG Ferrites for Circulator/Isolator (서큘레이터/아이솔레이터용 YIG 페라이트의 첨가제와 자기적 특성 연구)

  • 윤휘영;유승규;이수형;윤종남;김정식
    • Journal of the Korean Ceramic Society
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    • v.38 no.12
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    • pp.1155-1161
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    • 2001
  • Yittrium Iron Garnet(YIG) has been used as an important material in the circulator/isolator which is used in RF communication system, mobile phone, adn satellite broadcasting, etc. In this study, we investigated the microstructural and magnetic properties of YIG ferrites with the sintering temperature and additives. We fabricated the YIG ferrites substituted with Ca, In, V by the traditional ceramic sintering method at 1250$\^{C}$, 1275$\^{C}$, 1300$\^{C}$ and 1325$\^{C}$. Powders were granulated by using a spray dryer. Crystallographic and microstructural properties were measured by using XRD and SEM. Magnetic properties were measured by using a VSM for saturation magnetization (4$\pi$M$\_$s/) and FMR (Ferromagnetic Resonance) experiment for ferromagnetic resonance line width (△H). The YIG ferrite, Y$\_$1.6/Ca$\_$1.4/Fe$_4$V$\_$0.7/In$\_$0.3/O$\_$12/, sintered at 1300$\^{C}$, showed higher saturation magnetization and lower ferromagnetic resonance line width than any other sintering temperatures.

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Synthesis of La0.7Sr0.3Mn1-xIrxO3 thin-films in search of superconductivity

  • Byeongjun Seok;Youngdo Kim;Donghan Kim;Jongho Park;Changyoung Kim
    • Progress in Superconductivity and Cryogenics
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    • v.25 no.2
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    • pp.10-13
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    • 2023
  • High-TC superconductivity (HTSC) has been the central issue in the field of condensed matter physics for decades. An essential part of the research on superconductivity is finding new exotic superconductors. It was recently suggested that Ir-substituted La0.7Sr0.3MnO3 (LSMIO) is a new high-TC superconductor. However, systematic studies to experimentally verify the superconductivity have not been done. Here, we report the growth processes of LSMIO thin films and their electrical transport properties. We observed a clear negative correlation between the intensity of the laser utilized for film deposition and the Curie temperature of the deposited film. We attributed this effect to the suppression of Sr concentration in the LSMIO films as the laser intensity increased. However, our LSMIO films show conventional ferromagnetism instead of HTSC. To realize the HTSC in LSMIO systems, further exploration of diverse compositions of LSMIO compounds is essential.

Synthesis of ${\beta}-({\alpha}$-Benzenesulfonamidobenzal)hydrazine and Its Derivatives (${\beta}-({\alpha}$-Benzenesulfonamidobenzal)hydrazine 및 그 유도체의 합성)

  • Tae-Rin Kim;Tae-Seong Huh;In-Sup Han;Yun-Ok Baik
    • Journal of the Korean Chemical Society
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    • v.23 no.5
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    • pp.307-313
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    • 1979
  • Seven new hydrazine derivatives were prepared from N-Aryllsufonylbenzimidoyl chloride. These were: ${\beta}-({\alpha}-Benzenesulfonamidobenzal)hydrazine\;(II),\;{\beta}-({\alpha}-Benzenesulfonamidobenzal)dimethylmethylenehydrazine\;(III),\;{\beta}-({\alpha}-Benzenesulfonamidobenzal)phenylhydrazine\;(VII),\;{\beta}-({\alpha}-Benzenesulfonamidobenzal)-4-nitrophenylhydrazine\;(VIII),\;{\beta}-({\alpha}-Benzenesulfonamidobenzal)-2,4-dinitrophenylhydrazine\;(IX),\;{\beta}-({\alpha}-Benzenesulfonamidobenzal)dimethylhydrazine\;(X),\;{\beta}-({\alpha}-Benzenesulfonamidobenzal)-p-methylphenylhydrazine\;(XI)$. The structure of these derivatives were identified by elemental analysis, spectral data and other chemical methods. In general, it was found that the yields of these reactions were significantly improved in polar solvent and by the electron attracting substituents in phenylhydrazine.

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A Study on the Preparation of Ion-Exchange Membranes with Polyphosphazenes (포스파젠 고분자를 이용한 이온교환 분리막 제조에 관한 연구)

  • Kwon, Suk-Ky;Lee, Byung-Chul
    • Applied Chemistry for Engineering
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    • v.9 no.3
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    • pp.435-439
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    • 1998
  • A new series of ion separation membrane materials based on pheonoxy and trifluoroethoxy co-substituted polyphosphazene has been designed and synthesized. The polymers were characterized by $^{31}P$ NMR, FT-IR spectroscopy, elemental analysis, and get permeation chromatography. The basic phosphazene membranes were sulfonated to obtain better hydrophilicity and ion-selectivity. The membrane from $[NP(OC_6H_4SO_3H)_{1.58}(OCH_2CF_3)_{0.42}]_n$ gave excellent values of ion transport number, area resistivity, and also ion exchange capacity, compared with the commercial membranes.

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Synthesis and Properties of Anionic Tetrakis(pentafluorophenyl)indium(Ⅲ) Complexes (Tetrakis(pentafluorophenyl)indium(Ⅲ) 음이온 착물의 합성과 특성)

  • Choi, Zel Ho
    • Journal of the Korean Chemical Society
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    • v.43 no.1
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    • pp.52-57
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    • 1999
  • The anionic complexes, [ln($C_6F_5)_4$]-, which are thermal and moisture sensitive, have been prepared by the reaction of In($C_6F_5)_3{\cdot}D(D=CH_3CN$, O($C_2H_5)_2$) with the system ($CH_3)_3SiC_6F_5$/CsF, $C_6F_5$MgBr or Cd($C_6F_5)_2$. The stable anionic indium(III) complexes are obtained through cation exchange with PNPCI ([PNP]= bis(triphenylphosphino)ammonium). The pure substance is obtained by column chromatography. These new anionic complexes are unambiguously identifed by NMR-spectroscopy, IR spectroscopy, molecular weight, DTA/TG and elemental analysis.

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