• Korean Journal of Crystallography
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• v.19 no.1
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• pp.7-13
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• 2008

고체 표면의 구조해석 방법에는 LEED(저에너지 전자선 회절법)나 RHEED(반사 고에너지 전자선 회절법) 등과 같이 표면의 2차원적 회절상을 해석하는 방법이 있고(역격자 공간의 해석), 또는 ISS(이온산란 분광법), RBS(러더포드 후방산란법) 등과 같이 표면 원자의 실공간에 대한 정보를 직접 얻는 방법이 있다. 실제로는 두 가지 종류의 분석법을 상호 보완적으로 조합하여 효율적인 구조해석을 수행한다. 본고에서는 직충돌 이온산란 분광법(ICISS: Impact Collision Ion Scattering Spectroscopy)에 대한 원리, 장치, 측정방법 등을 소개한 전고에 이어서 이를 이용한 반도체 표면구조 해석에 관하여 기술하고자 한다. 표면의 원자구조를 알아내기 위해서는 산란된 입자의 강도를 입사각도와 출사각도에 대하여 조사하여야 하는데, 이온이 원자와 충돌하여 산란될 때 원자의 후방으로 형성되는 shadow cone에 의하여 생성되는 집속 효과(focusing effect) 및 가리움 효과(blocking effect) 중에서 ICISS는 집속 효과만을 고려하여 해석하면 실공간에서의 원자구조를 해석할 수 있다. 본 고에서는 ICISS를 이용하여 금속 또는 절연체 물질이 반도체 표면 위에서 흡착 또는 성장될 때 초기의 계면 구조 해석, 금속/반도체 계면에서 시간에 따른 동적변화 해석, III-V족 반도체의 표면구조 해석, 반도체 기판 위에서 박막 성장 과정 해석 등에 관한 연구 사례를 소개하고자 한다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.332-341
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• 1998

Reaction kinetics for the solid - state reaction of ${\alpha}-Al_2O_3$with amorphous $SiO_2$to produce mullite ($3Al_2O_3;{cdot};2SiO_2$) was studied in the temperature range of 1450~$1480^{\circ}C$. Rate of kinetic reaction were determined by using $SiO_2$- coated $Al_2O_3$ compact containing 28.16 wt.% $SiO_2$and heating the reactant mixtures in MgO at definite temperature for various times. Amount of products and unreacted reactants were determined by X-ray diffractometry. Data from the volume fraction and ratio of peak intensities of mullite indicated that the reaction of ${\alpha}-;Al_2O_3$ with $SiO_2$to form $3Al_2O_3\;{\cdot}\;2SiO_2$ start between 1450 and $1480^{\circ}C$. The activation energy for solid-state reaction was determined by using the Arrhenius equation; The activation energy was 31.9 kJ/mol.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.109-116
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• 2003

The amount of radioactive waste is expected to be increased continuously because of the rapid growth of the domestic nuclear industry, full power operation of the HANARO reactor and the increased research activities of the nuclear fuel cycle. Accordingly the efforts are focused to achieve the handling of radioactive waste in safe and reduce the volume of radioactive waste. The PIEF is carrying out the PIE (post irradiation examination) of spent fuel rods related to the identification of cause defect and evaluation of integration safety. This study describes the technologies and experiences of compaction, shredding and cutting of the solid radioactive waste used in the PIE. The quantity of the high level waste was reduced by 1/12 using the 100-ton compressor installed in hot-cell. Also middle and low level waste was reduced by 1/8 using the 60-ton compressor installed in intervention area. Plastic drums were shredded by crusher to be compacted in the ratio of 1/5, used filters in the ratio of 1/6 and the number of drum is also reduced by cutting procedure for the non-volatile materials such as metal.

• Journal of the Korean Ceramic Society
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• v.41 no.8
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• pp.593-598
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• 2004

To make the all-solid-state lithium thin film battery having less than 1 fm in thickness, LiCoO$_2$ thin films were deposited on Pt/TiO$_2$/SiO$_2$/Si substrate as a function of Li/Co mole ratio and the deposition temperature by Pulsed Laser Deposition (PLD). Especially, LiCoO$_2$ thin films deposited at 50$0^{\circ}C$ with target of Li/Co=1.2 mole ratio show an initial discharge capacity of 53 $\mu$Ah/cm$^2$-$\mu$m and capacity retention of 67.6％. The microstructural and electrochemical properies of (Li, La)TiO3 thin films grown on LiCoO$_2$Pt/TiO$_2$/SiO$_2$/Si structures by Pulsed Laser Deposition (PLD) were investigated at various deposition temperatures. The thin films grown at 10$0^{\circ}C$ show an initial discharge capacity of approximately 51 $\mu$Ah/cm$^2$-$\mu$m and moreover show excellent discharge capacity retention of 90％ after 100 cycles. An amorphous (Li, La)TiO$_3$ solid electrolyte is possible for application to solid electrolyte for all-solid-state lithium thin film battery below 1 $\mu$m.

• Journal of Life Science
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• v.20 no.8
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• pp.1268-1275
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• 2010

This study was carried out to investigate the anti-proliferative activity of solid-state fermented medicinal herbs which include Phellinus baumii. Methanol extracts were prepared from 36 different medicinal herbs and their fermented counterparts. These extracts were used to treat human colorectal HCT116 cell, human embryonic kidney cell HEK-293, pre-adipocyte cell 3T3-L1, and pre-osteoblast cell MC3T3-E1 for 24 hr. At a concentration of 100 ${\mu}g/ml$, the extracts of Amomum villosum, Cnidium officinale Makino, Dendrobium moniliforme, Dictamnus dasycarpus, Diospyros kaki Thunb, Eucommia ulmoides Oliv, Ginkgo biloba L, Magnolia denudata Desrousseaux, Orostachys japonicus, Panax notoginseng, Pharbitis nil Choisy, Polygala tenuifolia and Trichosanthes kirilowii (seed) led to a < 50% decrease in cell proliferation, and mycelium of P. baumii showed a 46.3% decrease in cell proliferation. Meanwhile, the extracts of the 25 fermented herbs showed similar anti-proliferative activities compared to those of individual non-fermented herbs. However, the extracts of the fermented Drynaria fortunei Kunze (1), Lycium chinense Mill (2), Fritillaria thunbergii Miquel (3) and Prunus persica showed increased anti-proliferative activity. The $IC_{50}s$ of (1), (2) and (3) were especially decreased to 28, 85 and 80 ${\mu}g/ml$ from 394, 917 and 149 ${\mu}g/ml$, respectively. Furthermore, the cytotoxicity of the extracts of fermented (1), (2) and (3) against HEK-293, 3T3-L1, and MC3T3-E1was negligible up to 200 ${\mu}g/ml$. These results suggest that solid-state fermentation using the mycellium of P. baumiiproduce potential anti-cancer agents or strengthen the bioactivity of medicinal herbs.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.2 no.2
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• pp.77-82
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• 1992

When a crystal is grown by FZ process, the melt zone is located at between the solid of upper and lower side and is kept by the solid-liquid interface tension. On the surface of the melt zone, a surface tension gradient is occured by the difference of temperature and solute concentration, it is the driving force of marangoni flow. The crystal even in the steady state growth can become imperfect for the dislocation distribution and the solute concentration in the peripheral region of the crystal are higher than those in the inner part and the probability of the formation of the defects such as voids, bubble penetration, secondary phase creation and crack is high near the solid-liquid interface. This is because the solid -liquid interface becomes irregular because of the local variation of temperature in that region due to marangoni convection.

• Journal of the Korean Vacuum Society
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• v.3 no.2
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• pp.239-246
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• 1994

Cd1-xCoxIn2Se4($\chi$=0.000, 0.001, 0.005, 0.10, 0.50) 단결정을 수직 Bridgman 방법으로 성장시키고 성장된 단결정의 조성 및 결정구조를 조사하고 광학적 특성을 연구하였다. 성장된 단결정은 pesudocubic 구조이고 격자상수는 조성$\chi$가 증가함에 따라 약간씩 감소하였다. 기초 흡수단 영역에서의 광흡수 spectra 측정에서 이 단결정들은 간접전이 및 직접전이 및 직접전이 energy gap을 갖고 있으며 이들 energy gap의 조성의존성은 조성이 $\chi$=0.00에서 $\chi$=0.016까지는 기울기가 같고 $\chi$=0.016에서 기울 기가 변화되어서 $\chi$=0.016에서 $\chi$=0.50까지는 같은 기울기를 갖고 있다. 이러한 현상은 $\chi$=0.016에서부터 CdIn2Se4 내에 cobalt를 포함한 새로운 물질이 형성되고 이 물질과 a-CdIn2Se4 사이에 고체고용체를 형 성하기 때문이다.

• 한국전기화학회:학술대회논문집
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• 2002.07a
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• pp.271-276
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• 2002

고체산화물 연료전지의 구성요소인 전해질의 $(La_{1-x}Sr_x)(Ga_{1-y}Mg_y)O_{3-\delta}$계의 결정상 및 미세구조특성을 연구하였다. Mg의 첨가량이 증가할수록 Sr의 고용량도 증가하였으며 Sr의 함량이 많으면 2차상인 $LaSrGa_3O_7$상이 생성되었으며 Mg의 첨가량이 증가함에 따라서는 $LaSrGaO_4$상이 생성되었다. $LaSrGaO_4$상이 생성된 경우에는 낮은 전도도를 나타내었으며 $LaSrGa_3O_7$상의 경우에는 전기전도도에 큰 영향을 미치지 않았다. 또한 Sr과 Mg 첨가량의 증가는 grain 성장을 억제하였으며 $(La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$는 $1000^{\circ}C$에서 0.1S/cm 정도의 전기전도도를 나타내었다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.2
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• pp.185-197
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• 1999

Heat transfer and solidification of liquid silicon in von-$K{\acute{a}}rm{\acute{a}}n$ swirling flow is investigated. The moving boundary is fixed for all times by a coordinate transformation, and finite difference method Is used to obtain the instantaneous location of the solid-liquid Interface and the heat transfer from the surfaces of solid and liquid. For small Stefan number or low wall temperature, the transient heat transfer from the surface of solid(QS(t)) is much larger than that from the liquid side of solid-liquid interface(QL(t)) and QL(t) reaches its quasi-steady-state value much faster than QS(t).

• The Journal of the Acoustical Society of Korea
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• v.17 no.2
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• pp.79-83
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• 1998

높은 온도에서 금속물질이 응고되는 동안에 물질의 구조는 결정성장속도비율에 따 라 크게 좌우된다. 유도초음파를 기초로 한 펄스-에코 초음파실험기술과 함께 고체-액체 경 계면의 위치와 속도를 실시간으로 측정할 수 있어 고체화되는 동안의 용광로 파라메터들을 조절하는데 사용될 수 있다. 실험은 Bridgman형의 용광로에서 CuMn-막대시료에 대하여 서로 다른 냉각비율로 수행되었다. 열적평형상태에서 경계면의 위치에 대한 측정분해능은 약10㎛이다.