• Title/Summary/Keyword: Garnet

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The Crytal-Phase Transition of $Y_xFe_{2-x}O_3(x=0.82)$ ($Y_xFe_{2-x}O_3(x=0.82)$의 결정상 변환)

  • Kim, Jeong-Gi;Kim, Yeong-Jin
    • Korean Journal of Materials Research
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    • v.6 no.3
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    • pp.305-308
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    • 1996
  • YxFe2-xO3(x=0.82)의 결정상 변환을 상온에서의 x선회절과 온도구간 80-541K에서의 Mossbauer 분광 방법에 의해서 연구하였다. Xtjs 회절선은 시료가 orthorhombic 결정상과 garnet 결정상이 공존하고 있으며, 공존비는 실험오차 범위내에서 garnet 구조가 orthorhombic 구조보다 우세함을 보인다. 공존상중에서 garnet 구조의 자기상 변환온도는 536$\pm$5 K로 결정하였다. Debye 모형을 이용한 Mossbauer 스펙트럼의 recoil-free fration 분석결과는 garnet 결정상내의 d자리나 a자리에 vacancy의 존재 가능성을 시사한다. 부가적으로 시료가 포함하는 각 결정상의 Debye 특성온도를 결정하였다.

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Microstructure and Magnetic Characteristics of Yttrium Iron Garnet Thin Films Prepared by RF Magnetron Sputter (고주파 마그네트론 스퍼터법에 의해 제조된 Yttrium Iron Garnet 박막의 미세구조 및 자기적 특성)

  • 박명범;김병진;조남희
    • Journal of the Korean Ceramic Society
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    • v.36 no.3
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    • pp.293-300
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    • 1999
  • 고주파 마그네트론 스퍼터법을 이용한 YIG(yttrium iron garnet)박막 제조시 기판유형, 기판온도, 스퍼터전력, 스퍼터가스 등의 증착변수와 증착후 열처리 조건이 YIG 박막의 결정성, 화학조성, 미세구조 그리고 자기적 특성에 미치는 영향에 대하여 고찰하였다. 75$0^{\circ}C$ 이상의 온도에서 수행한 증착후 열처리에 의하여 비정질 박막이 결정화되었으며, 특히 GGG(gadolinium gallium garnet)기판 위에 제조된 박막은 강한 (111)우선배향성을 나타냈다. 박막조성은 스퍼터가스 내의 산소분율에 민감하게 영향을 받았으며, 산소분율이 20%인 스퍼터가스를 사용하여 제조된 박막은 Y2.88Fe3.84O12의 조성을 나타내었다. 증착후 열처리 온도가 90$0^{\circ}C$로부터 110$0^{\circ}C$로 증가함에 따라, GGG 기판위의 박막의 표면거칠기는 2.5nm에서 40nm로 증가하였으며, 보자력과 강자성 공명 선폭은 감소하였다.

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A Study on Drying Shrinkage of the High-Strength Concrete using the Garnet (가네트를 활용한 고강도 콘크리트의 건조수축 특성 연구)

  • Jang Ju-Young;Yoon Yo-Hyun;Park Jung-Min;Kim Wha-Jung
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.676-679
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    • 2004
  • In this study, we considered the characteristic of drying shrinkage from age of high strength concrete with garnet minute powder to be industry by-product. The factors of experiment are unit water content$(160kg/m^3)$, water-binder ratio(30, $35\%$), fine aggregate ratio(40, 42, $44\%$), admixture replacement ratio(0, 10, $20\%$), admixture type(garnet minute powder, fly ash, blast-furnace slag). We make a comparative study of shrinkage about concrete with a passage of age(1, 3, 7, 14, 28, 56, 91 days). As a result of experiment, we reach a conclusion as follow. In the same mix condition, as unit water content and fine aggregate ratio go up, the drying shrinkage ratio increase. In the drying shrinkage ratio according to admixture replacement ratio, it goes up when admixture replacement Ratio increase in case of fly ash and blast-furnace slag. But, drying shrinkage ratio decrease when admixture replacement ratio increase in case of garnet minute powder.

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Fluorophotometric Determination of Basic Drugs with Lumogallion, Superchrome Garnet Y and Their Alkyl Derivatives (루모갈리온, 슈퍼크롬 가넷 와이 및 그 알킬 유도체에 의한 염기성 의약품의 형광정량)

  • 송만영;김동오;이은엽;안문규
    • YAKHAK HOEJI
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    • v.37 no.3
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    • pp.209-215
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    • 1993
  • Basic drugs could be extracted as ion-paired complexes with Lumogallion, Superchrome Garnet Y and their alkyl derivatives from aqueous acid solution, and then determined fluoro-metrically after addition of aluminum ion. The analysis was carried out as follows; To a 1 ml portion of basic drugs (10$^{-9}$~2$\times$0$^{-8}$mole/ml), 1ml of 0.01w/v% fluorescent reagent solution, and 10ml of dichloroethane are added. The mixture is stirred for 1 minute. After standing for a few minutes, the dichloroethane layer is transfered to 1 ml of 0.1w/v% Al(NO$_{3}$)$_{3}$ ethanol solution. After mixing, and standing for 30 minutes at room temperature, the fluorescence intensity is measured with each maximum excitation and emission wavelength. The reagent blank is run through the whole procedure. From the degree of enhancement of fluorescence intensity, hexyl and dodecyl lumogallion and Superchrome Garnet Y were judged to be the useful one of fluorescent reagent for basic drugs analysis.

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On the Genesis of Skarn-type Scheelite Deposits at the Dongmyoung mine (동명광산(東明鑛山)의 스카른형(型) 회중석(灰重石) 광상(鑛床)의 성인(成因))

  • Oh, Mihn-Soo;Park, Ki-Hwa
    • Economic and Environmental Geology
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    • v.16 no.1
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    • pp.37-49
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    • 1983
  • The skarn type tungsten deposits are developed in the contact aureole of Jurassic biotite-hornblende granodiorite and limestone beds. The latter can be divided into the Great Limestone Series of Joseon System and Gabsan Formation which is correlative to the Hongjeom Series of Pyeongahn System. The skarns are impregnated in the limestone, sandstone, schist and granodiorite, and showing zonal distribution. The five skarn zones are from fresh limestone inwards to wollastonite-skarn, clinopyroxene-skarn, clinopyroxene-garnet skarn, garnet skarn and vesuvianite skarn zone. The ore mineral, scheelite, disseminates in the clinopyroxene-garnet and vesuvianite skarn zone, and the size of the scheelite crystals in vesuvianite skarn zone is larger than in clinopyroxene- garnet skarn zone. According to the mineral paragenesis and the composition of skarn minerals, oxygen fugacity ($fo_2$) is low. Fluid inclusions in quartz comprise much $LCO_2$ and fluid inclusion studies revealed that the homogenization temperatures range $240-290^{\circ}C$.

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Adsorption Characteristics of Malachite Green Employing Waste Garnet as Adsorbent (폐석류석을 흡착제로 이용한 말라카이트그린 흡착 특성)

  • Baek, Mi-Hwa;Kim, Dong-Su
    • Journal of Korean Society on Water Environment
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    • v.23 no.2
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    • pp.216-221
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    • 2007
  • The adsorption characteristics of malachite green on waste garnet have been investigated for its treatment from aqueous solution by employing waste garnet which is generated from the abrasive production process as an adsorbent. The influential factors examined were the initial concentration of malachite green in solution, reaction temperature, and the amount of adsorbent. Also, the effect of the modification of the surface of adsorbent on adsorption was examined. As the initial malachite green was increased with reaction temperature and the color removal of malachite green-containing solution was promoted with the amount of adsorbent. Finaly, increased adsorption of malachite green could be attained when the surface of glass was modified by hexamethyldisilazane.

Synthesis and Characterization of Polyphase Waste Form to Immobilize High Level Radioactive Wastes (고준위 방사성 폐기물의 고정화를 위한 다상 고화체 합성)

  • Chae Soo-Chun;Jang Young-Nam;Bae In-Kook;Ryu Kyung-Won
    • Economic and Environmental Geology
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    • v.39 no.2 s.177
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    • pp.173-180
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    • 2006
  • The synthesis of polyphase waste form, which is an immobilization matrix fur the high level radioactive wastes, was performed with the mixed composition of garnet and spinel $(Gd_3Fe_5O_{12}+(Ni_xMn_{1-x})(Fe_yCr_{1-y})_2O_4)$ in the range of 1200 to $1400^{\circ}C$. The phases synthesized from all stoichiometric compositions were garnet, perovskite, and spinel. Especially, garnet was synthesized only in the composition of the highest content of Fe(y=0.9), whereas it was not synthesized in other compositions. This result indicated that the content of Fe was closely related to the formation of garnet. The composition of garnet revealed that the content of Gd was exceeded and that of Fe was depleted. Preferential distribution of elements in the phases can be attributed to the nonstoichiometric composition of garnet.

A study on the identification of ruby and garnet by optical method (광학적 방법에 의한 루비와 가넷의 감별법에 관한 연구)

  • Hwang Ji-Ho;Choi Jong-Koen
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.15 no.5
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    • pp.182-187
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    • 2005
  • The FT-IR absorption spectrum by the lattice vibrations of ruby and garnet obtained from FT-IR shows quite different characteristics. By the UV-VIS spectroscopy it was found that the ruby has two transmission bands in red and blue region, while garnet has only one transmission band in red region. The color filter to distinguish ruby from garnet was developed and named HWANG JI HO filter. Through the HWANG JI HO filter, ruby was shown in blue color and garnet was shown in dark red color because of the only the blue region transmittance of the filter. Other red stones, such as spinel, tourmaline were shown in dark red color like as garnet. The ruby could be recognized easily from the red stone.