• 한국표면공학회지
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• 제38권4호
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• pp.174-178
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• 2005

Chemical vapor deposition technique has been used to grow epitaxial SiC thin films on Si wafers using tetramethylsilane(TMS) precursor. The films were observed to grow along (110) direction of 3C-SiC at $800^{\circ}C$. The quality of the films was significantly influenced by the TMS flow rate and growth temperature. Nanocrystal SiC films were grown at flow rates of TMS 10 sccm with $H_2$ carrier gas of 100 sccm. The temperature and gas pressure in the reactor have a great influence on the crystallinity and morphology of the SiC film grown. The growth mechanism of the SiC film on the Si substrate without the carbonization process was discussed based on the experimental results.

• 대한방사선치료학회지
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• 제29권2호
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• pp.75-81
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• 2017

목 적: 전립선암 환자에 대한 비침습적이고 피폭선량에 대한 부담이 없는 초음파를 이용한 영상유도방사선치료의 Setup 오차 분석을 통해 치료의 재현성을 평가해 보고자 한다. 대상 및 방법: 치료가 종료된 전립선암 환자 26명의 1,105영상에 대하여 앞-뒤(anterior-posterior, AP), 좌-우(right-left, RL), 위-아래(superior-inferior, SI) 방향의 Setup 오차에 대해 평균, 표준편차와 3D-error을 분석하였다. 또한 오차범위 0-1 mm, 1-3 mm, 3-5 mm, 5 mm 이상에 대한 각 오차 빈도수(frequency, %) 분석을 통하여 AP, RL, SI 방향에 대한 방향성을 확인 하였다. 결 과: Setup 오차는 AP, RL, SI 방향에 대하여 평균과 표준편차는 $1.87{\pm}1.36mm$, $1.73{\pm}1.22mm$, $2.01{\pm}1.40mm$였다. 3D-error는 평균 $3.63{\pm}1.63mm$였다. 각 방향에 대한 Setup 오차값의 빈도(frequency, %)는 AP 방향에 대한 오차범위 0-1 mm에서 29 %, 1-3 mm에서 50.2 %, 3-5 mm에서 19.6 %, 5 mm 이상에서 1.3 %였다. RL 방향에 대하여 오차범위 0-1 mm에서 31.3 %, 1-3 mm에서는 52.5 %, 3-5 mm에서는 15.8 %, 5 mm 이상에서 0.5 %였다. 마지막으로 SI 방향에 대한 오차범위 0-1 mm에서 26.3 %, 1-3 mm에서 50.2 %, 3-5 mm에서 22.4 %, 5 mm 이상에서 1.1 %였다. 결 론: Setup error는 SI 방향에서 $2.01{\pm}1.40mm$로 가장 컸으며 오차 빈도는 모든 방향에서 50 % 이상 오차 범위 1-3 mm에 들어온 것으로 확인되었다. $Clarity^{TM}$ Auto scan을 이용한 초음파영상유도 방사선치료는 치료 전에 방광의 전처치 상태, target의 구조 등을 관찰이 가능하고, 치료 중 target의 움직임을 실시간으로 monitoring하여 빠른 repositioning이 가능하다. 결과적으로 초음파를 이용한 실시간 영상유도방사선치료는 치료의 재현성을 높일 수 있을 것으로 사료된다.

• 한국전기전자재료학회논문지
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• 제18권11호
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• pp.1048-1055
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• 2005

The formula to calculate a variation of optical path length of single crystal by the electric field was derived by this study. The formula was applied to $Bi_{12}SiO_{20}$ single crystal. The results are as follows. In case of the applied electric field in the body diagonal direction and the passing light along the same direction, the variation of optical path length had the largest value. The symmetry of the space distribution of optical path length satisfied $E3C_2\;8C_3$, the set of elements of the symmetry of $Bi_{12}SiO_{20}$ single crystal. The property which gave the largest influence to the variation of optical path length is the strain of length by the Inverse piezoelectric effect. The second influence, is the variation of the refractive index by the electro-optic effect. The variation of optical path length by the inverse piezoelectric effect and by the electro-optic effect have a reverse sign each other.

• 한국재료학회지
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• 제18권9호
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• pp.482-485
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• 2008

Tetragonal-$Ni_{1-x}Pd_x$Si/Si (001) structure was studied by using density functional theory (DFT). An epitaxial interface between $2{\times}2{\times}4$ (001) tetragonal-NiSi supercell and $1{\times}1{\times}2$ (001) Si supercell was first constructed by adjusting the lattice parameters of B2-NiSi structure to match those of the Si structure. We chose Ni atoms as a terminating layer of the B2-NiSi; the equilibrium gap between the tetragonal-NiSi and Si was calculated to be 1.1 ${\AA}$. The Ni atoms in the structure moved away from the original positions along the z-direction in a systematic way during the energy minimization. Two different Ni sites were identified at the interface and the bulk, respectively. The two Ni sites at the interface have 6 and 7 coordination numbers. The Ni sites with coordination number 6 at the interface were located farther away from the interface, and were more favorable for Pd substitution.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.186-186
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• 2011

[100] 방향으로 4$^{\circ}$ 기울어진 Si(001)-2${\times}$1(vicinal surface)을 초고진공하(UHV)에서 청결하게 하고 열처리하면 rebonded-atom을 가진 DB double step과 이 step에 나란한 아홉 개의 dimer를 가진 평균 폭이 4.0 nm인 single-domain의 (001)-2${\times}$1 테라스의 면으로 재구조된다 [그림 a]. 본 연구에서는 이 표면 위에 Sb을 상온에서 증착하여 덮고 후열처리하면(2 ML, 500$^{\circ}C$ 10 분), Sb-dimer가 Si 표면을 한 층 덮고 (001) 테라스의 Sb-dimer 방향이 DA double-step과 수직을 이루는 1${\times}$2 구조를 이룬다는 사실을 STM으로 확인하였다 [그림 b]. 이러한 Sb-passivation의 효과는 표면 Si-dimer의 부분적으로 채워진 dangling-bond를 Sb-dimer의 완전히 채워진 고립쌍(lone-pair)으로 바꿈으로써 표면 자유 에너지를 줄이고, 나아가 계면 Si 층은 bulk에 유사하게 되는 데에 있다. 이 passivation 된 표면은 Ge/Si 등의 heteroepitaxy에 사용할 수 있고, 특히 single-domain을 유지하며 step 방향에 대해 평행인 dimer-row로 이루어져 있어서 원자나 전자의 이동에 비등방적 효과를 증가시킬 것이 예측된다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1263-1265
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• 2007

The electrical characteristics of low temperature poly-Si (LTPS) thin-film transistors (TFT) with channel parallel and perpendicular to the direction of lateral growth were studied. The poly-Si film was crystallized using sequential lateral solidification (SLS) laser crystallization technique. The channel orientation dependent turn-on characteristics were investigated by using gated-diodes and capacitance-voltage measurements

• 한국세라믹학회지
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• 제27권5호
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• pp.698-701
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• 1990

The necessary conditions for the growth of high quality Bi12SiO20 single crystals by the Czochralski method have been determined. The interface of melt and crystal was transformed convex to concave above 7 rpm. For growth <001> and <111> directions, facet morphology exhibited 4-fold and 6-fold symmetry. When the crystal of <001> growth direction was broadened, minor facet {110} was developed outstandingly.

• Journal of Magnetics
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• 제3권2호
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• pp.44-48
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• 1998

Scanning Electron Microscopy with Polarization Analysis (SEMPA) was used to image the surface magnetic domain structure of the 100 ${\mu}{\textrm}{m}$ thick 3% Si-Fe sheet. The thin-gauged 3% Si-Fe strips with magnetic induction ($B_{10}$) from 1.98 to 1.57 Tesla were prepared via conventional metallurgical processes including melting, hot-and cold-rolling, intermediate annealing and final annealing. Using SEMPA, it was observed that the $B_{10}$ (1.98 T) Tesla sample was almost composed of 180$^{\circ}$ stripe domains which are parallel to rolling direction. On the other hand the 3% Si-Fe sheet with $B_{10}$ (1.57 T) Tesla was composed of large 180$^{\circ}$stripe domains that are slanted about 30$^{\circ}$to the rolling direction and complex magnetic domain structures like tree and zigzag pattern. The 180$^{\circ}$stripe domains, which covered a major part of the sample, had (110)<001> Goss texture parallel to the rolling direction. The domain walls between 180$^{\circ}$stripe domains were the conventional Bloch type walls. On the other hand, the 90$^{\circ}$domains, which covered minor part on edge of the sample, were observed in (200) grains. The domain walls between 90$^{\circ}$domains were the Neel type walls. In high magnification, the elliptical singularity at the Neel walls was clearly observed.

• 월간포장계
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• 통권286호
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• pp.42-48
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• 2017

• 반도체디스플레이기술학회지
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• 제7권3호
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• pp.35-39
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• 2008

We study the interaction of acetone molecule $[(CH_3)_2CO]$ on Si(001) surface using density functional theory. An acetone molecule is adsorbed on a Si atom of the Si dimer of the Si(001) surface. The adsorption of the acetone molecule on the Si atom at lower height between the two Si atoms of the dimer is more favorable than that on the Si atoms at upper height. Then we calculate an energy variation of dissociation and four-membered ring structures of the acetone molecule adsorbed on the Si surface. Total energy difference between the two structures is about 0.05 eV, indicating that the two structures are almost equally stable. Energy barrier exists when a hydrogen atom is dissociated and adsorbed on the other Si atom of the dimer, while energy barrier does not exist when the adsorbed acetone molecule changes to four-membered ring structure, except for the rotation of the acetone molecule along z-direction. Therefore, four-membered ring structure is kinetically more favorable than the dissociation structure when the acetone molecule is adsorbed on the Si(001) surface.