• The Korean Journal of Ceramics
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• 제4권3호
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• pp.204-206
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• 1998

The Gibbs free energy of formation of $BaThO_3$ from elemental oxides has been measured at temperatures between 853 and 903 K using a $CaF_2$ solid electrolyte galvanic cell. The galvanic cell consisted of Pt, $O_2, CaO+CaF_2 \parallel CaF_2 \parallelBaThO_3+ThO_2+BaF_2, O_2$, Pt EMF gave the standard Gibbs free energy for the reaction $CaF_2+BaThO_3=CaO+BaF_2+ThO_3$ as $\DeltaG^o$,/TEX>=124111.031-117.597 T(J/mol).

• 한국재료학회:학술대회논문집
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• 한국재료학회 1997년도 한국재료학회 추계학술발표회
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• pp.32-32
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• 1997

• Nuclear Engineering and Technology
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• 제52권6호
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• pp.1099-1109
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• 2020

The performance of gadolinium burnable absorber (GdBA) for reactivity control in UO₂ and (U, Th)O₂ fuels and its impact on spent fuel characteristics was performed. Five fuel assemblies: one without GdBA fuel rod and four each containing 16, 24, 34 and 44 GdBA fuel rods in both fuels were investigated. Reactivity swing in all the FAs with GdBA rods in UO₂ fuel was higher than their counterparts with similar GdBA fuel rods in (U, Th)O₂ fuel. The excess reactivity in all FAs with (U, Th)O₂ fuel was higher than UO₂ fuel. At the end of single discharge burn-up (~ 49.64 GWd/tHM), the excess reactivity of (U, Th) O₂ fuel remained positive (16,000 pcm) while UO₂ fuel shows a negative value (-6,000 pcm), which suggest a longer discharge burn-up in (U, Th)O₂ fuel. The concentration of plutonium isotopes and minor actinides were significantly higher in UO₂ fuel than in (U, Th)O₂ fuel except for ²³⁶Np. However, the concentration of non-actinides (gadolinium and iodine isotopes) except for ¹³⁵Xe were respectively smaller in (U, Th)O₂ fuel than in UO₂ fuel but may be two times higher in (U, Th)O₂ fuel due to its potential longer discharge burn-up.

• 한국군사과학기술학회지
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• 제18권2호
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• pp.139-145
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• 2015

In this paper, the flexible piezoelectric nanocomposite generator(NCG) device based on $BaTiO_3$ nanostructures was fabricated via simple and low-cost spin coating method. The $BaTiO_3$ nanostructures synthesized by self-assembly reaction showed dendrite morphologies. To produce the piezoelectric nanocomposite(p-NC layer) which acts as an electric energy source in NCG device, the piezoelectric nanopowders($BaTiO_3$) were dispersed in polydimethylsiloxane(PDMS). Sequently, the p-NC layer was inserted in two dielectric layer of PDMS; these layers enabled the NCG device flexibility as well as durability prohibiting detachment(exfoliation) for significantly mechanical bending motions. The fabricated NCG device shows average maximum open circuit voltage of 6.2 V and average maximum current signals of 300 nA at 20 wt% composition of $BaTiO_3$ nanostructures in p-NC layer. Finally, the flexible energy harvester generates stable output signals at any rate of frequency which were used to operate LCD device without any external energy supply.

• 전자공학회논문지A
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• 제31A권9호
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• pp.121-127
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• 1994

The capability for application of rf magnetron sputterred and post annealed BaTiO$_{3}$ thin films in dielectrics AC drived TFELD(thin film electroluminescent device) was investigated. The dielectric constant of the thin films slightly increased up to about 25 with increase fothe post annealing temperature in the range of 210$^{\circ}C$-480$^{\circ}C$. The dielectric loss was about 0.005-0.01 except for the high frequency range above 100kHz and nearly independent on post annealing temperature. The BaTiO$_{3}$ thin film used for TFELD was annealed at 480.deg. C and Si$_{3}$N$_{4}$ thin film was inserted between BaTiO$_{3}$, lower dielecrics and ZnS:Mn, phosphor layer for stable driving of the device and for fear of interdiffusion. Regardless of the frequency of the applied sine wave voltage, the threshold voltage of the prepared TFELD was 65volt and saturated brightness was about 3000cd/m$^{2}$ at 130volt(2kHz sine wave), 65volt above V$_{TH}$.

• 한국전기전자재료학회논문지
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• 제35권2호
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• pp.103-118
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• 2022

With the recent increase in demand for electronic devices, multi-layer ceramic capacitors (MLCCs) have become the most important core component. In particular, the next-generation MLCC with extremely high reliability is required for the 4^th industrial revolution and electric vehicle applications. Therefore, it is necessary to develop dielectric ceramic materials with high dielectric properties and reliability. During the decades, electrical properties of BaTiO₃ based dielectric ceramics, which have been widely used in MLCC industrial field, have been improved by microstructure and defect chemistry control. However, electrical properties of BaTiO₃ have reached their limits, and new types of dielectric materials have been widely studied. Based on these backgrounds, this report presents the recent development trends of BaTiO₃-based dielectric materials for the next-generation MLCCs, and suggests promising candidates to replace BaTiO₃ ceramics.

• 헤리티지:역사와 과학
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• 제55권3호
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• pp.120-129
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• 2022

본 연구는 조선시대 대형 불화 10점에 사용된 회청 안료에 대하여 에너지분산형X-선분광기를 이용하여 화학 조성 분석을 시행하고, 편광현미경과 주사전자현미경을 이용하여 형태적 특성을 관찰하여 재질 및 특성을 밝히고자 한다. 화학 조성 분석에 의하면, 10개의 대형 불화의 회청은 모두 주제로 SiO₂, 융제로 K₂O를 사용한 포타쉬 유리로 판단된다. 착색제로 사용한 코발트 광석과 관련된 성분 외에도 As₂O₃, BaO, PbO가 높게 검출되는 대형 불화가 확인된다. 회청 입자들은 일정한 형태가 없고, 다양한 색도의 청색을 띤다. 일부 입자에서는 패각상의 깨짐, 구 모양의 기포, 불순물이 관찰된다. 반사전자상을 통해 AD 18세기 초반의 대형 불화에서 나온 회청은 As가 높은 회청만 검출되었으나 AD 18세기 중반 이후의 대형 불화에서 나온 회청에서는 입자마다 다양한 명암 차이가 확인되었으며 As, Ba, Pb 등이 높은 회청이 검출된다. 이상의 결과를 통해 조선시대 대형 불화의 회청 유형은 3가지로 구분된다. A형은 As₂O₃가 높은 유형, B형은 BaO가 높은 유형, C형은 PbO가 높은 유형이다. 회청 안료의 3가지 유형을 대형 불화의 제작 시기별로 살펴보면, A형은 중간에 검출되지 않은 시기도 있지만 1705년부터 1808년까지 사용이 확인되며, B형과 C형은 1750년부터 출현하여 1808년까지 사용된 것을 알 수 있다. 이는 AD 18세기 초반까지는 한 가지 유형의 회청만 사용되었고, AD 18세기 중반부터는 하나의 대형 불화 안에서도 여러 유형의 회청이 혼합되어 사용된 것을 알 수 있다. 이와 같은 연구는 당시 대형 불화를 제작할 때 사용한 회청 안료의 특성을 이해할 수 있는 정보를 제공할 것으로 기대된다.

• 암석학회지
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• 제12권3호
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• pp.119-134
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• 2003

육십령 복운모화강암은 광물학$.$지화학적으로 과알루미나 성질을 특징적으로 나타낸다. 육십령 화강암체는 1.15∼l.20 범위의 높은 알루미나 포화 지수와 2.20∼2.98wt% 범위의 높은 CIPW norm 강옥 함량을 나타낸다. 색지수는 <16%이고, FeO$^{T}$ +MgO+TiO$_2$,는 평균 1.9 wt%로서 우백질화강암에 해당한다. 육십령 복운모 우백질화강암은 SiO$_2$성분이 증가함에 따라, TiO$_2$, $Al_2$O$_3$, FeO, Fe$_2$O$_3$, MgO, CaO, $K_2$O, P$_2$O$_{5}$ , Rb, Ba, Sr 은 감소하는 경향을 나타내는 반면, Zr과 Th는 증가하는 경향을 나타내는데, 이는 장석, 흑운모, 인회석 저어콘의 분별경정작용에 기인한 것으로 해석된다. 거정질 암맥에는 SiO$_2$and P$_2$O$_{5}$ 는 높게, 그 외의 주원소는 결핍되어 나타난다. Manaslu, Hercynian 복운모 우백질화강암, Lachlan습곡대의 S-형 화강암과 비교해 보면, 육십령 복운모 우백질화강암은 낮은 Rb, 높은 Ba, Sr을 나타낸다. 거정질 암맥의 지화학적 특징은 육십령 복운모화강암을 형성했던 멜트로부터 일부 원소들의 제거 혹은 유동성에 의해 높은 Rb, Nb와, 낮은 Ba, Sr, Zr, Th, Pb 함유를 나타낸다. 육십령 복운모 우백질화강암은 총 휘토류 함량이 95.7∼123.3ppm 범위를 나타내며, 운석에 대해 표준해보면, 저 내지 중정도의 Eu 이상(Eu/Eu＊= 0.7∼0.9)을 가지면서 경희토류원소가 풍부하고 중희토류원소가 결핍된 매우 경사가 져 있는((La/Yb)$_{N}$ = 6.9∼24.8) 변화를 보여준다. 반면에 페그마틱 암맥은 총 휘토류원소의 함량이 7.0ppm으로 운석에 대해 표준화하면, 강한 부의 Eu 이상(Eu/Eu＊= 0.2)을 가진 편평한 양상을 나타낸다. 복운모 우백질화강암을 형성했던 멜트의 성분은 기원암 뿐만 아니라 기원암이 녹은 후의 잔류물질의 양에도 의존한다. 특히 CaO/$Na_2$O의 비와 Rb/Sr-Rb/Ba의 비들은 강한 과알루미나질 화강암에서는 기원암의 성분에, 즉, 기원암의 사장석과 점토 함량 비에 주로 의존한다. 육십령 복운모 우백질화강암은 사장석 성분보다 점토 성분이 풍부한 암석에서 기원한 Manaslu와 Hercynian 복운모 우백질화강암들(예를 들면 Millevaches와 Gueret)보다는 더 높은 CaO/$Na_2$O의 비와 더 낮은 Rb/Sr-Rb/Ba 비를 나타내고 있는데, 이러한 지화학적 특징은 점토 성분보다는 사장석이 풍부한 석영장석질 암석으로부터 기원했던 것으로 사료된다.

• 자원환경지질
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• 제30권1호
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• pp.35-49
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• 1997

The coal formation of the Deokpyeong area are interbedded along metapelites of the Ogcheon Supergroup, which are composed mainly of graphite, quartz, muscovite and associated with small amounts of biotite, chlorite, pyrite and barite. The ratios of $SiO_2/Al_2O_3$, $Al_2O_3/Na_2O$ and $K_2O/Na_2O$ of the coaly metapelite are variable and wide range from 1.80 to 10.21, from 27.8 to 388.8 and from 7.6 to 61.8, respectively. These coal formation were deposited in basin of marine environments, and the REE of these rocks are not influenced with metamorphism and hydrothermal alterations on the basis of $Al_2O_3$ versus La, La against Ce, the ratios of La/Ce (0.19 to 0.99) and Th/U (0.02 to 4.75). These rocks also show much variation in $La_N/Yb_N$ (1.19 to 22.89), Th/Yb (0.14 to 21.43) and La/Th (0.44 to 13.67), and their origin is explained by derivation from a mixture of sedimentary and igneous rocks. The wide range in trace and REE element characteristics as Co/Th (0.12 to 2.78), La/Sc (0.33 to 10.18), Sc/Th (0.57 to 5.73), V/Ni (8 to 2347), Cr/V (0.02 to 0.67) and Ni/Co (1.56 to 32.95) of these coaly metapelites argues for inefficient mixing of the various source lithologies during sedimentation. Deep to pale green barium-vanadium muscovites (vanadium-oellacherite) have been found in this coal formations. Modes of occurrence and grain size of muscovite are heterogeneous, but most of the barium and vanadium-bearing muscovites occur along the boundaries between graphite and quartz grains, ranging from 200 to $350{\mu}m$ in length and from 40 to $60{\mu}m$ in width. Results of X-ray diffraction data of the minerals characterized to be monoclinic system with $a=5.249{\AA}$, $b=8.939{\AA}$, $c=20.924{\AA}$ and ${\beta}=95.894^{\circ}$. Representative chemical formula of the muscovite was $(Na_{0.09}K_{1.44}Ba_{0.46})(Al_{2.75}Ti_{0.07}V_{0.56}Fe_{0.08}Mg_{0.50})(Si_{6.12}Al_{1.88})O_{22}$. The V possibly substitute octahedral Al, and the Ba is coupled substitution of $K^+Si^{4+}=Ba^{2+}Na^+Ca^{2+}$, which compositional ranges of V and Ba are from 0.42 to 0.69 and from 0.34 to 0.56 based on $O_{22}$, respectively. Formation mechanism of the barium-vanadium muscovites in the coaly metapelite is shown that the formed by high pressure and temperature from regional metamorphism origanated during diagenesis at the interface between a basinal brine and organic matter.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 춘계학술대회 논문집
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• pp.3-5
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• 1993

It is very important that a spectrum of reflectance is in accord wi th a spectrum of absorbance for a effective heating. Therefore. the objective of this study was to achieve a technical composite for material plan which PTC thermistor increase a radiation property of far-infrared and keep a characteristic of R-T The Ceramic speciman studies had the composition $BaTiO_3$ with additive of 1.67 $Al_2O_3$, 3.75 $SiO_2$, 1.25 $TiO_2$, 0.15 $Sb_2O_3$ and 0.00-0.182 $MnO_2$. $MnO_2$ amounts of additives was both increase on the anomalous resistivity-temperature characteristics and high efficiency on the radiation properties bodies of far-infrared. This result shows that specimens produced high emissivity(average 0.8) of far-infrared at 4.5-15$[{\mu}m]$ by measuring a characteristic of IR and R-T.