• Journal of Magnetics
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• 제10권1호
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• pp.14-22
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• 2005

Precisely refined Mossbauer study and nano structure observation revealed that intergranular phase formed between a-Fe and Nd₂Fe₁₄B phase in NdFeNbB alloys plays a significant role on the magnetic properties. The intergranular interaction was characterized in term of Henkel Plot (δM plot), and hyperfine field, quardrupole splitting and isomer shift were refined to predict the presence and role of the intergranular phase. By the addition of Nb into Nd₈Fe₈₆B₆ composition, coercivity was found to increase by 25% due to the refinement of average grain size of both the soft and hard magnetic phases which was decreased from 50 nm of virgin Nd/sub 8/Fe/sub 86/B/sub 6/ to 25 nm in Nd₈Fe ₈₅Nb₁B₆ alloys. The role of Nb addition was confirmed to stabilize the Nd₂Fe₁₄B lattice preventing from thermal vibration of the corresponding sites substituted Fe by Nb atoms in all sites in the Nd₂Fe₁₄B lattice. The enhanced coercivity was originated from the exchange hardening of soft and amorphous phases surrounding the hard magnetic Nd₂Fe₁₄B crystal.

• 한국광물학회지
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• 제4권2호
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• pp.129-140
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• 1991

Two illite polytypes, 2M1 and 1Md, have been identified from the sericite deposits of the Bobae mine, Kimhae, Kyungsangnam-do. Each polytype has characteristic grain size, chemical composition, and occurrence. 2M1 illite occurs predominantly in the sericitic alteration zone, while 1Md illite occurs predominantly in the propylitic alteration zone, implying that the former was formed in the higher temperature than the latter. Illites can be subdivided into two types based on their crystal sizes;(1) the $\mu\textrm{m}$-sized illite which is below 0.01mm(100$\mu\textrm{m}$) in size and consists of 2M1 and 1Md type, (2) the mm-sized illite which is above 0.01mm in size and consists only of 2M1 type. Especially illite below 1$\mu\textrm{m}$ is premominantly of 1Md type. Therefore, it seems likely that illite crystal size is to some extent related to the polytype. XRD data show that there is no interstratified layer in illites regardless of the crystal size and polytype. Activity of muscovite component of the $\mu\textrm{m}$-sized illite is 0.843 while that of the mm-sized illite is 0.790. However, the latter is more similar to muscovite in crystal structure than the former is. The mm-sized illite has less Al and more Kthan the $\mu\textrm{m}$-sized illite. In both illites, Si contents show a positive relation to octahedral Mg. Fluid inclusion study and mineral association show that the formation temperature of illite is $270-330^{\circ}C$. The major chemical processes leading to the formation of sericitic deposit as well as the alteration zones are the leaching of SiO2 from the country rock and the addition of Al2O3 and K2O into the sericitic ores.

• 대한전기학회논문지
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• 제41권5호
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• pp.517-524
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• 1992

In this study, 0.10Pb(SbS11/2TSnS11/2T)OS13T-(0.90-x)PbZrOS13T (0.25 x 0.40) ceramics were fabricated by the atmospheric method. The sintering temperature and time were 1250[$^{\circ}C$] and 2[2hr], respectively. The structureal, dielectric and piezoelectric properties with composition of PbTiOS13T were studied. As the results of XRD ans SEM, the crystal structure of a specimen was rhombohedral, lattice constant and average grain size were decreased with increasing the contents of PbTiOS13T. Relative dielectric constant and Curie temperature were increased with increasing the contents of PbTiOS13T, 0.10PSS-0.40PT-0.50PZ specimen had the highest values of 904 and 265[$^{\circ}C$], respectively. In increasing of PbTiOS13T contents form 25[mol%] to 40[mol%], piezoelectric charge constant and electromechanical coupling factors were increased form 114[pC/N] to 142[pC/N], 17[%] to 24[%] and mechanical quality factor were decreased with increasing the contents of PbTiOS13T. In the 0.10PSS-0.40PT-0.50PZ specimens, those values were 14.2[kV/cm] and 9.43[x10S0-6TC/cmS02T], resectively.

• 한국세라믹학회지
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• 제35권10호
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• pp.1040-1048
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• 1998

Ferroelectric properties of{{{{ { { { {SrBi }_{2 }Ta }_{2-x }Nb }_{x }O }_{9 } }} (SBIN) thin films were affected by the amount of Bi content in SBTN. The addition of Bi into the SBTN films could be accomplished by heat treating SBTN/Bi2O3/SBTN het-erostructures fabricated by r.f. magnetron sputtering method. The variation of Bi content was controlled by changing the thickness of the sandwiched Bi2O3 in SBTN/Bi2O3/SBTN heterostructure from 50 to 400$\AA$. As changing the thickness of the sandwiched Bi2O3 in Bi2O3 films was increased from 0 to 100$\AA$ the grain grew faster and the ferroelectric pro-perties were improved. On the other hand when the thickness of Bi2O3 films was thicker than 150$\AA$ the fer-roelectric properties were deteriorated Especially for SBTN thin films inserted by 400$\AA$ Bi2O3 layer a Bi2Phase appeared as a second phase resulting in poor ferroelectric properties. The maximum remanent po-larization (2Pr) and coercive field(Ec) were obtained for the SBTN/Bi2O3/(100$\AA$)/SBTN thin films. In this case 2Pr and Ec were 14.75 $\mu$C/cm2 and 53.4kV/cm at an applied voltage of 3V respectively.

• 한국세라믹학회지
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• 제35권8호
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• pp.871-877
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• 1998

Cu-In 금속증을 증착한 뒤, 이를 selenization하는 이단계 방법에 의하여 $CuInSe_2$ 박막을 형성하였다. CuIn 금속층은 co-sputtering 방법을 이용하여 상온에서 증착하였다. $Cu_{11}In_{9}$ 상과 $CuIn_2$ 상이 공존하였고, Cu의 양이 증가할 수록 $Cu_{11}In_{9}$ 상이 많이 존재하였다. Selenization은 진공과 상압의 두가지 조건에서 증착하였다. 상압하에서 증착할 때보다 진공중에서 증착할 때, 더 소수의 화합물만을 형성하고 낮은 온도에서 $CuInSe_2$ 단일상을 형성하였다. 이로인해 진공중에서 증착하였을 때 표면 거칠기가 적고 입자가 크며 결정성이 좋은 $CuInSe_2$ 박막을 얻을 수 있었다.

• 한국세라믹학회지
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• 제45권4호
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• pp.245-249
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• 2008

The SiC and ZrC are critical and essential materials in TRISO coated fuel particles since they act as protective layers against diffusion of metallic and gaseous fission products and provides mechanical strength for the fuel particle. However, SiC and ZrC have critical disadvantage that SiC loses chemical integrity by thermal dissociation at high temperature and mechanical properties of ZrC are weaker than SiC. In order to complement these problems, we made new combinations of the coating layers that the ZrC layers composed of SiC. In this study, after Silicon carbide(SiC) were chemically vapor deposited on graphite substrate, Zirconium carbide(ZrC) were deposited on SiC/graphite substrate by using Zr reaction technology with Zr sponge materials. The different morphologies of sub-deposited SiC layers were correlated with microstructure, chemical composition and mechanical properties of deposited ZrC films. Relationships between deposition pressure and microstructure of deposited ZrC films were discussed. The deposited ZrC films on SiC of faceted structure with smaller grain size has better mechanical properties than deposited ZrC on another structure due to surface growth trend and microstructure of sub-deposited layer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.154-157
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• 2003

$TiO_2$ thin films were fabricated by RF magnetron sputtering system at by controlling deposition times, ratios of $Ar:O_2$ partial presser ratio and substrate conditions. And the surface, cross-section morphology, microstructure, and composition ratio of the films were analyzed by FE-SEM, TEM and XPS. Besides, the optical absorption and transmittance of the $TiO_2$ films were measured by a UV-VIS-NIR Spectrophotometer, and photocatalytic properties were studied by G${\cdot}$C Analyzer & Data Analysis system. As the result, when $TiO_2$ thin film was made at deposition time of 120[min] and $Ar:O_2$ ratio of 60:40, the best structural and optical properties among many thin films could be accepted. The best results of properties were as follows: thickness; 360~370[nm), grain size; 40[nm], gap between two peak binding energy; $5.8{\pm}0.05[eV]$ ($2_{p3/2}$ peak and $2_{p1/2}$ peak of Ti was show at $458.3{\pm}0.05[eV]$ and $464.1{\pm}0.05[eV]$ respectively), binding energy; $530{\pm}0.05[eV]$, optical energy band gap; 3.4[eV].

• 한국제4기학회지
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• 제23권1호
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• pp.1-24
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• 2009

정동진 지역 단구를 피복하고 있는 고토양층은 배수가 잘 되지만 주기적으로 물에 잠기는 환경에서 형성되었다고 추정된다. 4.5m에 달하는 퇴적단면에서는 모두 6개의 층이 관찰된다. 고토양의 입자는 주로 점토 및 실트 크기이나 부분적으로 모래 크기 입자의 우점 구간이 있다. 주요 구성 광물은 석영, 장석, 운모와 녹니석이다. 고토양의 지화학적 조성은 전 층에 걸쳐 큰 차이가 없으나 화학적 풍화지수는 깊이에 따른 변화를 보여준다. 대자율의 변화는 토양층의 변화와 일치하는 양상이다. 고토양층의 상부 50cm에는 토양쐐기 층이 발달해 있고, 이 층준에서는 약 25,000년 전 분출한 AT 화산재 입자가 집중적으로 발견된다. 고토양층 하부의 사력층에서는 약 11만년의 OSL 연대가 얻어졌다.

• 한국해양환경ㆍ에너지학회지
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• 제5권1호
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• pp.68-75
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• 2002

본 조사는 유기오염원으로 지적되고 있는 진해만내 수하식 양식장을 대상으로 저서생물상을 이용한 환경 평가를 실시하여 저서환경내 유기오염 양상을 측정하였다. 굴과 진주담치 양식장과 양식활동이 이루어지지 않은 대조구 등 세 개 정점을 대상으로 퇴적물 특성과 저서동물을 조사하였다. 세 지역 모두 평균 입도분포가 6.0~6.6Ф로 니질 퇴적상을 나타냈다. 퇴적물 내 유기물 함량은 진주담치 양식장이 2.8%로 놀게 나타났으며, 대조구의 경우 1.5%로 나타났다 총 7개 동물군, 79종의 저서동물이 채집되였으며, 대조구가 양식장에 비하여 저서생물의 종 다양성과 서식밀도가 높은 상이한 군집구조를 나타냈다. 특히, 굴과 진주담치 양식장에서는 퇴적물내 유기물 함량이 높은 지역에 나타나는 기회종으로 알려진 Lumbrlneris longlfolia, Heteromastus. filiformis, Corophium sinenie 등이 우점하였다. 계절별로 종조성과 서식밀도에서 다소 차이를 보임에도 불구하고, 생물상을 이용한 환경평가 결과에서는 진주담치 양식장의 경우 대조구나 굴 양식장에 비해 유기오염이 진행되고 있는 것으로 나타났다.

• Applied Biological Chemistry
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• 제32권3호
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• pp.209-215
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• 1989

숙주나물의 수분함량, 신장도, 질소함량 및 각 단백질 분획들의 전기영동 패턴과 아미노산조성을 비교 분석하여 다음과 같은 결과를 얻었다. 숙주나물의 신장도는 재배방법에 의해 약간 달라질 수 있으나 온도가 높을수록 신장도는 커지고 온도가 낮으면 신장도는 작아지나 우리가 섭취할 수 있는 가식부는 크게 나타난다. Weber 변법에 의한 숙주나물의 분회별 단백질 함량은 glutelin량이 가장 많고 globulin, albumin 순이었다. 발아중에 추출율의 차이는 있었으며 대체로 단백질량은 감소하는 것으로 나타났다. 단백질 분획들을 전기영동하여 관찰한 결과 모든 녹두단백질들이 발아기질로 이용되어 발아기간이 늘어날수록 단백질량의 감소를 확인할 수 있었으며, 발아시간에 의한 숙주나물의 신장도와 단백질변화를 비교해 볼 때 상품적 가치로서는 발아 4일이 최적조건임을 알 수 있었다. 아미노산 조성은 Asp, Glu을 월등히 많이 함유하였으며, 전반적으로 발아가 진행됨에 따라 산성 아미노산은 감소하고 염기성 아미노산은 증가하는 경향을 나타냈으며 다른 아미노산들은 발아중 유의할 만한 변화는 없었다.