• International Journal of Internet, Broadcasting and Communication
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• 제7권1호
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• pp.75-92
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• 2015

This paper presents the application of the bond valence method to estimate the valence charge distribution in several perovskite systems: $La_{{\tilde{1}}x}Pb_xMnO_3$ (x=0.1-0.5), $La_{0.6}Sr_{0.{\tilde{4}}x}Ti_xMnO_3$ (x=0.0-0.25) and $La_{{\tilde{1}}x}Sr_xCoO_3$ (x=0.1-0.5); the reviewing of their crystal structures is also incorporated. The results showed the failure of the elastic bonding mechanism in all studied systems and revealed the general deficit of the valence charge in their unit cells. This valence deficit was not associated with the structural defects and was not equally localized in all coordination spheres. As the content of substitution increased, the charge deficit declined systematically from balanced level, signifying the transfer of valence charge from the ${\tilde{B}}O_6$ to ${\tilde{A}}O_{12}$ spheres. This transfer depended on the valence deviation of spheres and the average reached near 2 electron per unit cell. The possible impact of the limitted accuracy of the available structural data on the bond valence results has also been considered.

• 한국가금학회지
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• 제31권3호
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• pp.165-170
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• 2004

본 연구는 현미 급여에 대한 닭고기의 도체 및 육질 특성을 구명하기 위하여, 육계 대조구 사료(T1)에서 옥수수를 현미로 50% 대체한 대조구 사료(T2)와 100% 현미(T3) 대체구로 구분하여 사육하고, 도축 후 닭고기의 육질 특성을 평가하였다. 도체 무게는 대조구 사료만 급여하였을 때보다 현미급여 수준을 증가시켰을 때 점차 감소하는 경향을 나타냈다. 부분육에서 가슴살 생산율은 대조구 사료 및 100% 현미 대체구에서 17.3～17.9%를 나타낸 반면, 50% 현미 대체 대체구는 18.6%로 생산율이 증가하는 경향을 나타내었다. 육색에서 명도(L＊)는 대조구 사료만 급여하였을 때보다 현미 급여수준을 높였을 때 점차 감소하는 경향을 나타냈으며, 황색도(b＊)도 대조구 사료 급여구가 8.25, 50% 현미 대체구 4.84, 100% 현미 대체구 4.47으로 현미 수준이 증가할수록 유의적으로 감소하는 경향을 나타내었다(P < 0.05). 전단력은 대조구사료만 급여했을 때보다 현미 급여수준이 높아질수록 증가하는 경향을 나타내었다. 가열감량은 대조구 사료에서 22.90%, 50% 현미 대체구 23.49%, 100% 현미 대체구 24.50%로 현미의 수준이 높아질수록 약간씩 증가하는 경향을 나타내었다. 지방산 조성에서 필수지방산인 linoleic acid( $C_{18：2}$, n6) 함량은 대조구 사료 급여구가 33.21%, 50% 현미 대체구 31.89%, 100% 현미 대체구 27.89%로 현미 급여 수준이 높아질수록 유의적으로 감소하는 경향을 나타내었으며(P < 0.05), 불포화지방산 총량(UFA)은 대조구 사료 급여구가 76.85%, 50% 현미 대체구 77.22%, 100% 현미 대체구 75.49%로 나타났으며, n6/n3의 비율에서는 대조구 사료 급여구의 경우 19.89%로 비교적 높았고, 현미 50% 대체구 17.73%, 현미 100% 대체구 17.01%으로 감소하는 경향을 나타내었다. 이상에서 언급한 바와 같이 도체무게, 육색, 전단력, 지방산등을 고려할 때 현미 급여 수준을 대조구사료의 옥수수를 50%까지 대체하여도 닭고기 품질을 저해하지 않는 것으로 사료된다.다.

• 한국주조공학회지
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• 제35권6호
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• pp.147-154
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• 2015

The effects of Sc and Sr elements on the modification of the eutectic $Mg_2Si$ phase and the castability were investigated in the Al-4wt%Mg-0.9wt%Si-0.3wt%Mn-0.15wt%Fe alloy. Measurements of the cooling curve and microstructure observations were performed to analyze the additional effects of Sc and Sr minor elements during the solidification process. A prominent effect found on the modification of the eutectic $Mg_2Si$ phase with additions of the Sr and Sc elements. Here, a fine eutectic $Mg_2Si$ phase and a decrease in the growth temperature of the eutectic $Mg_2Si$ phase were evident with an addition of Sc element up to 0.2 wt%. The growth temperature of the eutectic $Mg_2Si$ phase decreased and the effect on the modification of the eutectic $Mg_2Si$ phase increased with the addition of Sr element up to 0.02 wt%. The addition of 0.02wt%Sr had the strongest effect on the modification of the eutectic $Mg_2Si$ phase, and the resulting microstructure of the eutectic $Mg_2Si$ phase was found to have a fibrous morphology with a decreased aspect ratio and an increased modification ratio. Fluidity and shrinkage tests were conducted to evaluate the castability of the alloy. The addition of 0.02wt%Sr effectively increased the fluidity of the alloy, while an addition of Sc did not show any effect compared to when nothing was added. The maximum filling length was recorded for 0.01wt%TiB-0.02wt%Sr owing to the effect of the fine ${\alpha}$-Al grains. The macro-shrinkage ratio decreased, while the micro-shrinkage ratio increased with the addition of various eutectic modifiers. The highest ratio of micro-shrinkage was recorded for the 0.02wt%Sr condition. However, the total shrinkage ratio was nearly identical regardless of the amounts added in this study.

• Progress in Superconductivity
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• 제5권1호
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• pp.50-54
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• 2003

We have fabricated $∂^2$$B_{z}$ /$∂x^2$ type planar gradiometers and studied their properties in operation under various field conditions. $YBa_2$$Cu_3$$O_{7}$ film was deposited on $SrTiO_3$ (100) substrate by a pulsed laser deposition (PLD) system and patterned into a device by the photolithography with ion milling technique. The device consists of 3 pickup loops designed symmetrically Inner dimension and the width of the square side loops are 3.6 mm and 1.2 mm, respectively, and the corresponding dimensions of the center loop are 2.0 mm and 1.13 mm. The length of baseline gradiometer is 5.8 mm. Step-edge junction width is 3.0 $\mu\textrm{m}$ and the hole size of the SQUID loop is 3 $\mu\textrm{m}$ ${\times}$ 52 $\mu\textrm{m}$. The SQUID inductance is estimated to be 35 pH. The device was formed on a 20 mm ${\times}$ 10 mm substrate. We have tested the behavior of the device in various field conditions. The unshielded gradiometer was stable under extremely hostile conditions on a laboratory bench. Noise level 0.45 pT/$\textrm{cm}^2$/(equation omitted)Hz and 0.84 pT/$\textrm{cm}^2$/(equation omitted)Hz at 1 Hz for the shielded and the unshielded cases, which correspond to equivalent field noises of 150 fT/(equation omitted)Hz and 280 fT/(equation omitted)Hz, respectively. In spite of the short baseline of 5.8 mm, the high common-mode-rejection-ratio of the gradiometer, $10^3$, allowed us to successfully record magnetocardiogram of a human subject, which demonstrates the feasibility of the design in biomagnetic studies.

• 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.

• 한국세라믹학회지
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• 제41권10호
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• pp.756-765
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• 2004

Colemanite($Ca_2B_6O_{11}{\cdot}5H_2O$)원광을 황산과 반응시켜 붕산을 추출하는 방법과 그 반응 기구에 대하여 연구하였다. colemanite에 황산을 첨가하고 가열하여 colemanite의 칼슘 성분을 황산칼슘으로 분리하고 붕산을 추출할 때, 첨가하는 황산 첨가량 은 colemanite에 존재하는 Ca 성분을 분리할 때 필요한 화학 양론적인 양보다 많아야 되며, 또한 초기 pH가 5 미만이어야 대부분의 colemanite가 분해되었다. 붕산으로 추출 시 영향을 주는 인자로는 분해온도, 분해시간, 황산 첨가량, 황산암모늄 첨가량, pH. 농축 정도 및 건조온도와 시간이었다. 황산 첨가 시 colemanite에 포함되어 있는 불순물 중 CaO와 MgO는 황산과 반응하여 침전을 형성하고, $SiO_2$는 불용 성분으로 황산칼슘과 함께 분리되고, $Al_2O_3,\;Fe_2O_3,\;TiO_2,\;Na_2O$ 등은 황산과 반응하여 액상 상태로 존재하였다. 이 액상에 암모니아를 첨가하여 존재하는 나머지 불순물을 수산화물 형태로 분리, 석출하였으며, pH 조정과 산성화, 농축, 재결정화 과정을 통하여 붕산을 제조하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.193-193
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• 2012

In thin film silicon solar cells, p-i-n structure is adopted instead of p/n junction structure as in wafer-based Si solar cells. PECVD is the most widely used thin film deposition process for a-Si:H or ${\mu}c$-Si:H solar cells. Single-chamber PECVD system for a-Si:H solar cell manufacturing has the advantage of lower initial investment and maintenance cost for the equipment. However, in single-chamber PECVD system, doped and intrinsic layers are deposited in one plasma chamber, which inevitably impedes sharp dopant profiles at the interfaces due to the contamination from previous deposition process. The cross-contamination between layers is a serious drawback of single-chamber PECVD system. In this study, a new plasma process to solve the cross-contamination problem in a single-chamber PECVD system was suggested. In order to remove the deposited B inside of the plasma chamber during p-layer deposition, a high RF power was applied right after p-layer deposition with SiH4 gas off, which is then followed by i-layer, n-layer, and Ag top-electrode deposition without vacuum break. In addition to the p-i interface control, various interface control techniques such as FTO-glass pre-annealing in O2 environment to further reduce sheet resistance of FTO-glass, thin layer of TiO2 deposition to prevent H2 plasma reduction of FTO layer, and hydrogen plasma treatment prior to n-layer deposition, etc. were developed. The best initial solar cell efficiency using single-chamber PECVD system of 10.5% for test cell area of 0.2 $cm^2$ could be achieved by adopting various interface control methods.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.137-137
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• 2009

Thin-film transistors (TFTs) that can be prepared at low temperatures have attracted much attention due to the great potential for flexible electronics. One of the mainstreams in this field is the use of organic semiconductors such as pentacene. But device performance of the organic TFTs is still limited by low field effect mobility or rapidly degraded after exposing to air in many cases. Another approach is amorphous oxide semiconductors. Amorphous oxide semiconductors (AOSs) have exactly attracted considerable attention because AOSs were fabricated at room temperature and used lots of application such as flexible display, electronic paper, large solar cells. Among the various AOSs, a-IGZO was considerable material because it has high mobility and uniform surface and good transparent. The high mobility is attributed to the result of the overlap of spherical s-orbital of the heavy pest-transition metal cations. This study is demonstrated the effect of thickness channel layer from 30nm to 200nm. when the thickness was increased, turn on voltage and subthreshold swing were decreased. a-IGZO TFTs have used a shadow mask to deposit channel and source/drain(S/D). a-IGZO were deposited on SiO2 wafer by rf magnetron sputtering. using power is 150W, working pressure is 3m Torr, and an O2/Ar(2/28 SCCM) atmosphere at room temperature. The electrodes were formed with Electron-beam evaporated Ti(30nm) and Au(70nm) structure. Finally, Al(150nm) as a gate metal was evaporated. TFT devices were heat treated in a furnace at $250^{\circ}C$ in nitrogen atmosphere for an hour. The electrical properties of the TFTs were measured using a probe-station to measure I-V characteristic. TFT whose thickness was 150nm exhibits a good subthreshold swing(S) of 0.72 V/decade and high on-off ratio of 1E+08. Field effect mobility, saturation effect mobility, and threshold voltage were evaluated 7.2, 5.8, 8V respectively.

• 대한치과교정학회지
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• 제28권5호
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• pp.775-782
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• 1998

동소 mRNA 보합결합법을 이용하여 백서의 실험적 치아 이동시 치은 상피에 있어서 견인측과 압박측의 표피성장인자 수용체의 발현을 관찰하여 다음과 같은 결과를 얻었다. 1. 대조군은 구강 상피의 기저세포층, 극세포층, 과립세포층, 각화층의 전층에 걸쳐 미약한 염색상을 보였으며 압박측, 견인측의 차이는 없었다. 2. 장치의 장착 시간 경과에 따라 반응의 정도가 증가하는 양상으로 나타났으며, 그 분포도 하부의 기저세포층에서 상부의 각화층으로 확산되었다. 전반적으로 반응정도에 있어 압박측과 견인측의 차이는 없었으나, 단지 장치 장착후 7일의 견인측 각화층에서만 압박측보다 반응의 정도가 약하게 나타났다. 3. 장치를 제거하면 시간이 경과함에 따라 표피성장인자의 발현 정도가 감소하여 제거후 7일에는 전층에 걸펴 경미한 양성반응을 보였으며 압박측과 견인측간의 차이는 없었다. 이상의 결과에서 미루어 볼 때 치아의 이동시에 EGFR의 증가는 치아 이동시에 가해지는 물리적 stress를 포함한 외부 환경의 변화로부터 치은 상피를 포함한 치주조직의 항상성을 유지하기 위한 반응으로 여겨진다.

• Journal of Periodontal and Implant Science
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• 제37권4호
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• pp.805-824
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• 2007

Purpose: Developments in micro/macrostructures of implants and surgical techniques brought out stable outcomes of implant dentistry. The aim of this study was to evaluate the distributions of implant patients, the types of implanted sites, and the success or survival rates of various implant systems and to analyze the implant placement done at each specificintraoral site and situation. Materials and Methods: The data of dental implantations collected between 1992 and 2006 at the Department of Periodontology in 00000 University Hospital were analyzed. Results: 1. Largest part of the patients were at the age of 40s and 50s in bothgender who lost their teeth mostly by periodontaldiseases and caries at the posterior intraoral sites as major ones. Bone densities of type II(mandible) and III(maxilla) were likely to be seen with quantity of type B. Lengths of the implants between 10 and 15 mm and wide platform took the largest part. 2. Survival rates of $Implantium^{(R)}(98.8%)$, $Xive^{(R)}(100%)$ and ITI $TE^{(R)}(100%)$ were high when $Frialit-2^{(R)}$ showed 82%(poor bone density area) or 87.2%(combined with additional therapy). $IMZ^{(R)}$ had lowest cumulative survival(67.5%) and success rate(49.4%) amongst all. 3. Replacement with 2 wide or 3 regular platforms showed no significant differences in survival rate and marginal bone loss atmandibular posterior area. In single restoration of mandibular second molar, 5-year success rate of machined surface $Br{\aa}nemark^{(R)}(70.37%)$ was lower than that of rough surface $ITI^{(R)}$ SLA(100%). 4. Replacement of single tooth in anterior area showed high survival rate of 94.5%. 5. The success rates of $Br{\aa}nemark$ Ti-Unite and ITI SLA at posterior maxilla with poor bone density both showed stable outcomes. 6. 10-year cumulative survival rate of implants with maxillary sinus augmentation by lateral window approach appeared to be 96.60%. Low survival rate(75%) was shown when there were more than two complications combined. Height of grafted bone remained stable above the implant apex. Conclusions : Rough surfaced implants showed stable outcomes in most of the situation including poor bone density and additional therapy combined.